WorldWideScience

Sample records for suppress pulsatile release

  1. Interleukin 1α inhibits prostaglandin E2 release to suppress pulsatile release of luteinizing hormone but not follicle-stimulating hormone

    International Nuclear Information System (INIS)

    Rettori, V.; McCann, S.M.; Gimeno, M.F.; Karara, A.; Gonzalez, M.C.

    1991-01-01

    Interleukin 1α (IL-1α), a powerful endogenous pyrogen released from monocytes and macrophages by bacterial endotoxin, stimulates corticotropin, prolactin, and somatotropin release and inhibits thyrotropin release by hypothalamic action. The authors injected recombinant human IL-1α into the third cerebral ventricle, to study its effect on the pulsatile release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) in conscious, freely moving, ovariectomized rats. Intraventricular injection of 0.25 pmol of IL-1α caused an almost immediate reduction of plasma LH concentration. To determine the mechanism of the suppression of LH release, mediobasal hypothalamic fragments were incubated in vitro with IL-1α (10 pM) and the release of LH-releasing hormone (LHRH) and prostaglandin E 2 into the medium was measured by RIA in the presence or absence of nonrepinephrine. 1α reduced basal LHRH release and blocked LHRH release induced by nonrepinephrine. In conclusion, IL-1α suppresses LH but not FSH release by an almost complete cessation of pulsatile release of LH in the castrated rat. The mechanism of this effect appears to be by inhibition of prostaglandin E 2 -mediated release of LHRH

  2. Pulsatile luteinising hormone releasing hormone for ovulation induction in subfertility associated with polycystic ovary syndrome

    NARCIS (Netherlands)

    Bayram, N.; van Wely, M.; Vandekerckhove, P.; Lilford, R.; van der Veen, F.

    2000-01-01

    BACKGROUND: In normal menstrual cycles, gonadotrophin releasing hormone (GnRH) secretion is pulsatile, with intervals of 60-120 minutes in the follicular phase. Treatment with pulsatile GnRH infusion by the intra-venous or subcutaneous route using a portable pump has been used successfully in

  3. Pulsatile gonadotrophin releasing hormone for ovulation induction in subfertility associated with polycystic ovary syndrome

    NARCIS (Netherlands)

    Bayram, N.; van Wely, M.; van der Veen, F.

    2004-01-01

    BACKGROUND: In normal menstrual cycles, gonadotrophin releasing hormone (GnRH) secretion is pulsatile, with intervals of 60-120 minutes in the follicular phase. Treatment with pulsatile GnRH infusion by the intravenous or subcutaneous route using a portable pump has been used successfully in

  4. Colon-specific pulsatile drug release provided by electrospun shellac nanocoating on hydrophilic amorphous composites.

    Science.gov (United States)

    Yang, Yao-Yao; Liu, Zhe-Peng; Yu, Deng-Guang; Wang, Ke; Liu, Ping; Chen, Xiaohong

    2018-01-01

    Colon-specific pulsatile drug release, as a combined drug controlled-release model, is a useful drug delivery manner for a series of diseases. New nanomedicines and related preparation methods are highly desired. With diclofenac sodium (DS) as a model drug, a new type of structural nanocomposite (SC), in which composite polyvinylpyrrolidone (PVP)-DS core was coated by shellac, was fabricated via modified coaxial electrospinning. For comparison, traditional PVP-DS monolithic hydrophilic nanocomposites (HCs) were generated using a traditional blending process. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), attenuated total reflectance-Fourier transform infrared (ATR-FTIR), water contact angle (WCA), and in vitro dissolution and ex vivo permeation tests were conducted to characterize the composites. SEM images demonstrated that both composites were linear nanofibers with smooth surface morphology and cross sections. TEM disclosed that the SCs had a thin shellac sheath layer of approximately 12 nm. XRD and ATR-FTIR results demonstrated that the crystalline DS was converted into amorphous composites with PVP because of favorable secondary interactions. WCA and in vitro dissolution tests demonstrated that the sheath shellac layers in SC could resist acid conditions and provide typical colon-specific pulsatile release, rather than a pulsatile release of HC under acid conditions. Ex vivo permeation results demonstrated that the SCs were able to furnish a tenfold drug permeation rate than the DS particles on the colon membrane. A new SC with a shellac coating on hydrophilic amorphous nanocomposites could furnish a colon-specific pulsatile drug release profile. The modified coaxial process can be exploited as a useful tool to create nanocoatings.

  5. New trends in combined use of gonadotropin-releasing hormone antagonists with gonadotropins or pulsatile gonadotropin-releasing hormone in ovulation induction and assisted reproductive technologies.

    Science.gov (United States)

    Gordon, K; Danforth, D R; Williams, R F; Hodgen, G D

    1992-10-01

    The use of gonadotropin-releasing hormone agonists as adjunctive therapy with gonadotropins for ovulation induction in in vitro fertilization and other assisted reproductive technologies has become common clinical practice. With the recent advent of potent gonadotropin-releasing hormone antagonists free from the marked histamine-release effects that stymied earlier compounds, an attractive alternative method may be available. We have established the feasibility of combining gonadotropin-releasing hormone antagonist-induced inhibition of endogenous gonadotropins with exogenous gonadotropin therapy for ovulation induction in a nonhuman primate model. Here, the principal benefits to be gained from using the gonadotropin-releasing hormone antagonist rather than the gonadotropin-releasing hormone agonist are the immediate inhibition of pituitary gonadotropin secretion without the "flare effect," which brings greater safety and convenience for patients and the medical team and saves time and money. We have also recently demonstrated the feasibility of combining gonadotropin-releasing hormone antagonist with pulsatile gonadotropin-releasing hormone therapy for the controlled restoration of gonadotropin secretion and gonadal steroidogenesis culminating in apparently normal (singleton) ovulatory cycles. This is feasible only with gonadotropin-releasing hormone antagonists because, unlike gonadotropin-releasing hormone agonists, they achieve control of the pituitary-ovarian axis without down regulation of the gonadotropin-releasing hormone receptor system. This capacity to override gonadotropin-releasing hormone antagonist-induced suppression of pituitary-ovarian function may allow new treatment modalities to be employed for women who suffer from chronic hyperandrogenemia with polycystic ovarian disease.

  6. A Novel Approach to Flurbiprofen Pulsatile Colonic Release: Formulation and Pharmacokinetics of Double-Compression-Coated Mini-Tablets.

    Science.gov (United States)

    Vemula, Sateesh Kumar

    2015-12-01

    A significant plan is executed in the present study to study the effect of double-compression coating on flurbiprofen core mini-tablets to achieve the pulsatile colonic delivery to deliver the drug at a specific time as per the patho-physiological need of the disease that results in improved therapeutic efficacy. In this study, pulsatile double-compression-coated tablets were prepared based on time-controlled hydroxypropyl methylcellulose K100M inner compression coat and pH-sensitive Eudragit S100 outer compression coat. Then, the tablets were evaluated for both physical evaluation and drug-release studies, and to prove these results, in vivo pharmacokinetic studies in human volunteers were conducted. From the in vitro drug-release studies, F6 tablets were considered as the best formulation, which retarded the drug release in the stomach and small intestine (3.42 ± 0.12% in 5 h) and progressively released to the colon (99.78 ± 0.74% in 24 h). The release process followed zero-order release kinetics, and from the stability studies, similarity factor between dissolution data before and after storage was found to be 88.86. From the pharmacokinetic evaluation, core mini-tablets producing peak plasma concentration (C max) was 14,677.51 ± 12.16 ng/ml at 3 h T max and pulsatile colonic tablets showed C max = 12,374.67 ± 16.72 ng/ml at 12 h T max. The area under the curve for the mini and pulsatile tablets was 41,238.52 and 72,369.24 ng-h/ml, and the mean resident time was 3.43 and 10.61 h, respectively. In conclusion, development of double-compression-coated tablets is a promising way to achieve the pulsatile colonic release of flurbiprofen.

  7. [Spermatogenesis of pulsatile gonadotropin-releasing hormone infusion versus gonadotropin therapy in male idiopathic hypogonadotropic hypogonadism].

    Science.gov (United States)

    Huang, Bingkun; Mao, Jiangfeng; Xu, Hongli; Wang, Xi; Liu, Zhaoxiang; Nie, Min; Wu, Xueyan

    2015-05-26

    To compare the efficacies of pulsatile gonadotropin-releasing hormone (GnRH) versus human chorionic gonadotropin/human menopausal gonadotropin (HCG/HMG) for spermatogenesis in male idiopathic hypogonadotropic hypogonadism (IHH). For this retrospective study, a total of 92 male IHH outpatients from May 2010 to October 2014 were recruited and categorized into GnRH (n = 40) and HCG/HMG (n = 52) groups. Each subject selected one specific therapy voluntarily. The gonadotropin levels were measured in the first week and monthly post-treatment in GnRH group. And serum total testosterone (TT), testicular volume (TV) and rate of spermatogenesis were observed monthly post-treatment in two groups. Spermatogenesis, TT and TV were compared between two groups. All IHH patients were treated for over 3 months. The median follow-up periods in GnRH and HCG/HMG groups was 8.2 (3.0-18.4) and 9.2 (3.0-18.6) months respectively (P = 0.413). In GnRH group, LH ((0.5 ± 0.6) vs (3.4 ± 2.4) U/L, P treatment. In GnRH group, at the end of follow-up, TT ((1.0 ± 1.0) vs (7.4 ± 5.2) nmol/L, P treatment time for initial sperm appearance than HCG/HMG group ((6.5 ± 3.1) vs (10.8 ± 3.7) months, P = 0.001). Pulsatile GnRH requires a shorter time for initiation of spermatogenesis than gonadotropin therapy in IHH male patients.

  8. Development and optimization of press coated tablets of release engineered valsartan for pulsatile delivery.

    Science.gov (United States)

    Shah, Sunny; Patel, Romik; Soniwala, Moinuddin; Chavda, Jayant

    2015-01-01

    The present work is aimed to develop and optimize pulsatile delivery during dissolution of an improved formulation of valsartan to coordinate the drug release with circadian rhythm. Preliminary studies suggested that β cyclodextrin could improve the solubility of valsartan and showed AL type solubility curve. A 1:1 stoichiometric ratio of valsartan to β cyclodextrin was revealed from phase solubility studies and Job's plot. The prepared complex showed significantly better dissolution efficiency (p valsartan β cyclodextrin complex was significantly higher (p valsartan β cyclodextrin complex were subsequently prepared and application of the Plackett-Burman screening design revealed that HPMC K4M and EC showed significant effect on lag time. A 3(2) full factorial design was used to measure the response of HPMC K4M and EC on lag time and time taken for 90% drug release (T90). The optimized batch prepared according to the levels obtained from the desirability function had a lag time of 6 h and consisted of HPMC K4M:ethylcellulose in a 1:1.5 ratio with 180 mg of coating and revealed a close agreement between observed and predicted value (R(2 )= 0.9694).

  9. Ovulation induction with pulsatile gonadotropin-releasing hormone (GnRH) or gonadotropins in a case of hypothalamic amenorrhea and diabetes insipidus.

    Science.gov (United States)

    Georgopoulos, N A; Markou, K B; Pappas, A P; Protonatariou, A; Vagenakis, G A; Sykiotis, G P; Dimopoulos, P A; Tzingounis, V A

    2001-12-01

    Hypothalamic amenorrhea is a treatable cause of infertility. Our patient was presented with secondary amenorrhea and diabetes insipidus. Cortisol and prolactin responded normally to a combined insulin tolerance test (ITT) and thyrotropin-releasing hormone (TRH) challenge, while thyroid-stimulating hormone (TSH) response to TRH was diminished, and no response of growth hormone to ITT was detected. Both luteinizing hormone (LH) and follicle-stimulating hormone (FSH) levels increased following gonadotropin-releasing hormone (GnRH) challenge. No response of LH to clomiphene citrate challenge was detected. Magnetic resonance imaging findings demonstrated a midline mass occupying the inferior hypothalamus, with posterior lobe not visible and thickened pituitary stalk. Ovulation induction was carried out first with combined human menopausal gonadotropins (hMG/LH/FSH) (150 IU/day) and afterwards with pulsatile GnRH (150 ng/kg/pulse). Ovulation was achieved with both pulsatile GnRH and combine gonadotropin therapy. Slightly better results were achieved with the pulsatile GnRH treatment.

  10. Induction of spermatogenesis and fertility in hypogonadotropic azoospermic men by intravenous pulsatile gonadotropin-releasing hormone (GnRH).

    Science.gov (United States)

    Blumenfeld, Z; Makler, A; Frisch, L; Brandes, J M

    1988-06-01

    Gonadotropin-releasing hormone (GnRH) has only recently become a helpful tool in the medication of hypogonadotropic hypogonadism (HH). Two azoospermic patients with HH who had previously been treated with hCG/hMG because of delayed puberty and each of whom had fathered a child after previous gonadotropin therapy were referred due to secondary failure of hCG/hMG treatment to induce spermatogenesis and fertility. A pulse study where blood was drawn every 15 minutes for LH, FSH and PRL RIAs was performed in each patient, and afterwards a bolus of i.v. GnRH was injected to assess gonadotropin responsiveness. A portable GnRH pump was connected to each patient so that it administered 5-20 micrograms of GnRH i.v. every 89 minutes. Spermatogenesis was first detected after 42 and 78 days respectively in the 2 treated HH men and 4 1/2 months from the start of treatment their wives became pregnant. No thrombophlebitis or other complications of the i.v. therapy occurred. In the case of the first patient, the semen was washed and concentrated and intra-uterine inseminations were carried out in an attempt to shorten the time needed to achieve fertility. The first pregnancy was successfully terminated at 38 weeks with the delivery of 2 heterozygotic normal male babies. The second pregnancy ended in spontaneous delivery of a healthy female. We conclude that i.v. pulsatile, intermittent GnRH administration is a safe, efficient and highly successful means of treating azoospermic men with HH.

  11. Pulsatile gonadotropin-releasing hormone therapy is associated with earlier spermatogenesis compared to combined gonadotropin therapy in patients with congenital hypogonadotropic hypogonadism

    Directory of Open Access Journals (Sweden)

    Jiang-Feng Mao

    2017-01-01

    Full Text Available Both pulsatile gonadotropin-releasing hormone (GnRH infusion and combined gonadotropin therapy (human chorionic gonadotropin and human menopausal gonadotropin [HCG/HMG] are effective to induce spermatogenesis in male patients with congenital hypogonadotropic hypogonadism (CHH. However, evidence is lacking as to which treatment strategy is better. This retrospective cohort study included 202 patients with CHH: twenty had received pulsatile GnRH and 182 had received HCG/HMG. Patients had received therapy for at least 12 months. The total follow-up time was 15.6 ± 5.0 months (range: 12-27 months for the GnRH group and 28.7 ± 13.0 months (range: 12-66 months for the HCG/HMG group. The median time to first sperm appearance was 6 months (95% confidence interval [CI]: 1.6-10.4 in the GnRH group versus 18 months (95% CI: 16.4-20.0 in the HCG/HMG group (P 1 × 10 6 ml−1 was 43.7% ± 20.4% (16 samples in the GnRH group versus 43.2% ± 18.1% (153 samples in the HCG/HMG group (P = 0.921. Notably, during follow-up, the GnRH group had lower serum testosterone levels than the HCG/HMG group (8.3 ± 4.6 vs 16.2 ± 8.2 nmol l−1 , P < 0.001. Our study found that pulsatile GnRH therapy was associated with earlier spermatogenesis and larger testicular size compared to combined gonadotropin therapy. Additional prospective randomized studies would be required to confirm these findings.

  12. Treatment of idiopathic hypogonadotropic hypogonadism in men with luteinizing hormone-releasing hormone: a comparison of treatment with daily injections and with the pulsatile infusion pump.

    Science.gov (United States)

    Shargil, A A

    1987-03-01

    Thirty husbands in childless couples, aged 24 to 35 years, were treated with luteinizing hormone-releasing hormone (LH-RH) for idiopathic hypogonadotropic hypogonadism (IHH) of peripubertal (incomplete) type. They were azoospermic or oligospermic, with less than 1.5 X 10(6)/ml nonmotile spermatozoa. The diagnosis of IHH was based on clinical and laboratory features and testicular biopsy specimen study and was further supported by results of stimulation tests and gonadotropin-releasing hormone (GnRH) test. Two treatment modalities were used: subcutaneous injections of 500 micrograms LH-RH twice daily; and perpetual subcutaneous injection, via portable infusion pump, of 25 ng/kg LH-RH, at 90-minute intervals. Two patients required a short second period of pulsatile treatment to cause a second pregnancy of their spouses. The pump proved to yield better results, compared with intermittent injections, in respect to endocrine responses, spermatogenesis, and fertility capacity. Normal levels of luteinizing hormone and follicle-stimulating hormone were reached in 2 to 3 weeks and normal testosterone levels in 8 to 10 weeks from the start of treatment. Sperm counts rose to greater than 60 X 10(6)/ml viable spermatozoa with less than 15% of abnormal forms in 3 to 5 months, and the wives conceived. Of a total of 18 deliveries of healthy infants, 12 offspring were identified genetically with their fathers. Four women were still pregnant at the conclusion of the study. The pump was well tolerated, without special operational problems to the patients. Pulsatile treatment is therefore recommended in the treatment of well-diagnosed and carefully selected cases of incomplete IHH.

  13. A mathematical model for LH release in response to continuous and pulsatile exposure of gonadotrophs to GnRH

    Directory of Open Access Journals (Sweden)

    Reed Michael C

    2004-09-01

    Full Text Available Abstract In a previous study, a model was developed to investigate the release of luteinizing hormone (LH from pituitary cells in response to a short pulse of gonadotropin-releasing hormone (GnRH. The model included: binding of GnRH to its receptor (R, dimerization and internalization of the hormone receptor complex, interaction with a G protein, production of inositol 1,4,5-trisphosphate (IP3, release of calcium from the endoplasmic reticulum (ER, entrance of calcium into the cytosol via voltage gated membrane channels, pumping of calcium out of the cytosol via membrane and ER pumps, and release of LH. The extended model, presented in this paper, also includes the following physiologically important phenomena: desensitization of calcium channels; internalization of the dimerized receptors and recycling of some of the internalized receptors; an increase in Gq concentration near the plasma membrane in response to receptor dimerization; and basal rates of synthesis and degradation of the receptors. With suitable choices of the parameters, good agreement with a variety of experimental data of the LH release pattern in response to pulses of various durations, repetition rates, and concentrations of GnRH were obtained. The mathematical model allows us to assess the effects of internalization and desensitization on the shapes and time courses of LH response curves.

  14. Concomitant inhibition of pulsatile luteinizing hormone (LH) and stimulation of prolactin release by prostacyclin (PGI2) in ovariectomized (OVX) conscious rats

    International Nuclear Information System (INIS)

    Ottlecz, A.; McCann, S.M.

    1988-01-01

    Prostacyclin (PGI 2 ) or its stable metabolite, 6-keto-PGF/sub 1 alpha/ in 2.5 μl 0.05 M phosphate buffer, was injected into the third ventricle (3 V) of ovariectomized (OVX), freely moving rats. Control animals received 2.5 μl of buffer. In the initial experiments a control blood sample was taken and then the PGI 2 was injected and frequent samples taken thereafter. With this protocol injection of 2 μg of PGI 2 produced a significant decrease in mean plasma LH only at 60 min after its injection, while the higher dose decreased plasma LH concentration at 30 and 60 min. In subsequent experiments, blood was removed from indwelling external jugular vein cannulae every 5-6 min during 2 hours and plasma LH and PRL levels were determined by radioimmunoassay. LH pulses were monitored and several parameters of LH pulsation were calculated during the hour before and after injection of phosphate buffer, PGI 2 or 6-keto-PGF/sub 1a/. Intraventricular injection of phosphate buffer failed to modify the characteristic pulsatile release of LH and did not alter plasma PRL levels. The amplitude of LH pulses was significantly reduced by PGI 2 and the inhibitory effect was dose-related. Even a dose of 1 μg produced a significant reduction in pulse height and the response was graded with maximal reduction occurring with the 5 μg dose which essentially abolished the LH pulses

  15. Imaging in pulsatile tinnitus

    International Nuclear Information System (INIS)

    Madani, G.; Connor, S.E.J.

    2009-01-01

    Tinnitus may be continuous or pulsatile. Vascular lesions are the most frequent radiologically demonstrable cause of pulsatile tinnitus. These include congenital vascular anomalies (which may be arterial or venous), vascular tumours, and a variety of acquired vasculopathies. The choice of imaging depends on the clinical findings. If a mass is present at otoscopy, thin-section computed tomography (CT) is indicated. In the otoscopically normal patient, there is a range of possible imaging approaches. However, combined CT angiography and venography is particularly useful

  16. Imaging in pulsatile tinnitus

    Energy Technology Data Exchange (ETDEWEB)

    Madani, G. [Radiology Department, St Mary' s Hospital, London (United Kingdom)], E-mail: gittamadani@yahoo.com; Connor, S E.J. [Neuroradiology Department, King' s College Hospital, London (United Kingdom)

    2009-03-15

    Tinnitus may be continuous or pulsatile. Vascular lesions are the most frequent radiologically demonstrable cause of pulsatile tinnitus. These include congenital vascular anomalies (which may be arterial or venous), vascular tumours, and a variety of acquired vasculopathies. The choice of imaging depends on the clinical findings. If a mass is present at otoscopy, thin-section computed tomography (CT) is indicated. In the otoscopically normal patient, there is a range of possible imaging approaches. However, combined CT angiography and venography is particularly useful.

  17. Continuous 24-hour intravenous infusion of recombinant human growth hormone (GH)-releasing hormone-(1-44)-amide augments pulsatile, entropic, and daily rhythmic GH secretion in postmenopausal women equally in the estrogen-withdrawn and estrogen-supplemented states.

    Science.gov (United States)

    Evans, W S; Anderson, S M; Hull, L T; Azimi, P P; Bowers, C Y; Veldhuis, J D

    2001-02-01

    How estrogen amplifies GH secretion in the human is not known. The present study tests the clinical hypothesis that estradiol modulates the stimulatory actions of a primary GH feedforward signal, GHRH. To this end, we investigated the ability of short-term (7- to 12-day) supplementation with oral estradiol vs. placebo to modulate basal, pulsatile, entropic, and 24-h rhythmic GH secretion driven by a continuous iv infusion of recombinant human GHRH-(1--44)-amide vs. saline in nine healthy postmenopausal women. Volunteers underwent concurrent blood sampling every 10 min for 24 h on four occasions in a prospectively randomized, single blind, within-subject cross-over design (placebo/saline, placebo/GHRH, estradiol/saline, estradiol/GHRH). Intensively sampled serum GH concentrations were quantitated by ultrasensitive chemiluminescence assay. Basal, pulsatile, entropic (feedback-sensitive), and 24-h rhythmic modes of GH secretion were appraised by deconvolution analysis, the approximate entropy (ApEn) statistic, and cosine regression, respectively. ANOVA revealed that continuous iv infusion of GHRH in the estrogen-withdrawn (control) milieu 1) amplified individual basal (P = 0.00011) and pulsatile (P < 10(-13)) GH secretion rates by 12- and 11-fold, respectively; 2) augmented GH secretory burst mass and amplitude each by 10-fold (P < 10(-11)), without altering GH secretory burst frequency, duration, or half-life; 3) increased the disorderliness (ApEn) of GH release patterns (P = 0.0000002); 4) elevated the mesor (cosine mean) and amplitude of the 24-h rhythm in serum GH concentrations by nearly 30-fold (both P < 10(-12)); 5) induced a phase advance in the clocktime of the GH zenith (P = 0.021); and 6) evoked a new 24-h rhythm in GH secretory burst mass with a maximum at 0018 h GH (P < 10(-3)), while damping the mesor of the 24-h rhythm in GH interpulse intervals (P < 0.025). Estradiol supplementation alone 1) increased the 24-h mean and integrated serum GH concentration

  18. Efficacy and safety of pulsatile gonadotropin-releasing hormone therapy among patients with idiopathic and functional hypothalamic amenorrhea: a systematic review of the literature and a meta-analysis.

    Science.gov (United States)

    Tranoulis, Anastasios; Laios, Alexandros; Pampanos, Andreas; Yannoukakos, Drakoulis; Loutradis, Dimitrios; Michala, Lina

    2018-04-01

    To systematically review and appraise the existing evidence in relation to the efficacy and safety of pulsatile gonadotropin-releasing hormone (pGnRH) for the treatment of women with hypothalamic amenorrhea (HA). Systematic review and meta-analysis. Not applicable. A total of 35 studies (three randomized and 32 observational) encompassing 1,002 women with HA. None. Primary outcomes: ovulation rate (OvR), pregnancy per ovulatory cycle rate (POR), and live birth per ovulatory cycle rate (LBOR). multiple gestation (MG), ovarian hyperstimulation syndrome (OHSS), and superficial thrombophlebitis (ST) rates. The summary measures were expressed as proportions and 95% confidence intervals (CI). Pulsatile GnRH treatment appears to achieve high OvRs. A trend toward high PORs and LBORs among women with HA is demonstrated. SC pGnRH achieves comparable OvR compared with IV pGnRH. The incidence of OHSS is low and of mild severity. Treatment with pGnRH is associated with low but slightly higher MG rates compared with the general population. IV administered pGnRH is rarely associated with ST. The high OvRs leading to a high rate of singleton pregnancies and the low likelihood of OHSS render the pGnRH treatment modality both effective and safe for the treatment of women with HA of either primary or secondary origin. Copyright © 2017 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  19. Suppressing Resistance to Bt Cotton with Sterile Insect Releases

    Energy Technology Data Exchange (ETDEWEB)

    Tabashnik, B E [Department of Entomology, University of Arizona, Tucson, AZ (United States); Sisterson, M S [USDA-ARS, San Joaquin Valley Agricultural Sciences Center, Parlier, CA (United States); Ellsworth, P C [Department of Entomology, University of Arizona, Maricopa Agricultural Center, Maricopa, AZ (United States)

    2011-01-15

    Genetically engineered crops that produce insecticidal toxins from Bacillus thuringiensis (Bt) are grown widely for pest control. However, insect adaptation can reduce the toxins' efficacy. The predominant strategy for delaying pest resistance to Bt crops requires refuges of non-Bt host plants to provide susceptible insects to mate with resistant insects. Variable farmer compliance is one of the limitations of this approach. Here we report the benefits of an alternative strategy where sterile insects are released to mate with resistant insects and refuges are scarce or absent. Computer simulations show that this approach works in principle against pests with recessive or dominant inheritance of resistance. During a largescale, four-year field deployment of this strategy in Arizona, resistance of pink bollworm (Pectinophora gossypiella) to Bt cotton did not increase. A multitactic eradication program that included the release of sterile moths reduced pink bollworm abundance by >99%, while eliminating insecticide sprays against this key invasive pest. (author)

  20. The Aversive Agent Lithium Chloride Suppresses Phasic Dopamine Release Through Central GLP-1 Receptors.

    Science.gov (United States)

    Fortin, Samantha M; Chartoff, Elena H; Roitman, Mitchell F

    2016-02-01

    Unconditioned rewarding stimuli evoke phasic increases in dopamine concentration in the nucleus accumbens (NAc) while discrete aversive stimuli elicit pauses in dopamine neuron firing and reductions in NAc dopamine concentration. The unconditioned effects of more prolonged aversive states on dopamine release dynamics are not well understood and are investigated here using the malaise-inducing agent lithium chloride (LiCl). We used fast-scan cyclic voltammetry to measure phasic increases in NAc dopamine resulting from electrical stimulation of dopamine cell bodies in the ventral tegmental area (VTA). Systemic LiCl injection reduced electrically evoked dopamine release in the NAc of both anesthetized and awake rats. As some behavioral effects of LiCl appear to be mediated through glucagon-like peptide-1 receptor (GLP-1R) activation, we hypothesized that the suppression of phasic dopamine by LiCl is GLP-1R dependent. Indeed, peripheral pretreatment with the GLP-1R antagonist exendin-9 (Ex-9) potently attenuated the LiCl-induced suppression of dopamine. Pretreatment with Ex-9 did not, however, affect the suppression of phasic dopamine release by the kappa-opioid receptor agonist, salvinorin A, supporting a selective effect of GLP-1R stimulation in LiCl-induced dopamine suppression. By delivering Ex-9 to either the lateral or fourth ventricle, we highlight a population of central GLP-1 receptors rostral to the hindbrain that are involved in the LiCl-mediated suppression of NAc dopamine release.

  1. Chrono pharmacotherapy: A pulsatile Drug Delivery

    Directory of Open Access Journals (Sweden)

    Huma Hameed

    2015-01-01

    Full Text Available Chronopharmacotherapy refers to a treatment in which controlled drug delivery is achieved according to circadian rhythms of disease by enhancing therapeutic outcomes and minimizing side effects. Colon targeting has gained great importance not only for the treatment of local diseases such as Crohn’s disease, inflammatory bowel disease and ulcerative colitis but also very important in systemic delivery of proteins/peptides, antiasthmatic drugs, antidiabetic agents and antihypertensive drugs, which mostly show their efficacy based on circadian rhythms of the body.Colon drug delivery is one of the difficult approaches to achieve the targeted and desired outcomes through pulsatile drug delivery by avoiding dose dumping.The main reasonbehind the use of pulsatile delivery is provision ofconstant drug release where a zero-order release is notpreferred. Chronopharmacotherapy in colon targeting play its role bymany systems such ascapsular systems, pulsatile system and osmotic systems, which are based on use of rupturable membranes and biodegradable polymers.The objective of this review article is to provide latest knowledge about drugs with chrono-pharmacological behavior entails night time dosing specially to the colon.

  2. Suppression of the Mediterranean fruit fly in Tunisia with released sterile insects

    International Nuclear Information System (INIS)

    Cheikh, M.; Howell, J.F.; Harris, E.J.; Salah, H.B.; Soria, F.

    1975-01-01

    The Government of Tunisia, U. S. Agency for International Development, and U. S. Department of Agriculture cooperatively developed a program for suppression of Ceratitis capitata (Wiedemann) in Tunisia. Mediterranean fruit flies were reared on an artificial diet, sterilized with 10 krad irradiation from a cobalt source, and the emerged adults were marked and then distributed by hand throughout the release area, 600 ha in the vicinity of Porto-Farina. Some aerial releases were made late in the season. Winter larval hosts were removed to lower the overwintering population, and sterile fly releases were begun early (Mar.1) to prevent fertile matings of flies that emerged during warm winter days. All fruit on the periphery of the release area was sprayed periodically (5 applications), as was the major fruit-growing areas within the region but outside the test zone, to minimize the possibility of fertile flies entering the release area. Daily from March to November, ca. 1,000,000 sterile flies were released. Trap catches indicated that the suppression obtained was about equal to that obtained using poison bait sprays. The early preferred host crops had no or negligible infestation (loquats, apricots, early peaches, and figs). The infestation of preferred summer fruits (peaches and figs) was reduced but not controlled. Less susceptible summer fruits were seldom infested. The estimated population was ca. 82.3 percent lower than in the previous year when no releases were made. Isolation and sterile fly distribution was inadequate to completely suppress the Mediterranean fruit fly population. (U.S.)

  3. Acute Stress Suppresses Synaptic Inhibition and Increases Anxiety via Endocannabinoid Release in the Basolateral Amygdala.

    Science.gov (United States)

    Di, Shi; Itoga, Christy A; Fisher, Marc O; Solomonow, Jonathan; Roltsch, Emily A; Gilpin, Nicholas W; Tasker, Jeffrey G

    2016-08-10

    Stress and glucocorticoids stimulate the rapid mobilization of endocannabinoids in the basolateral amygdala (BLA). Cannabinoid receptors in the BLA contribute to anxiogenesis and fear-memory formation. We tested for rapid glucocorticoid-induced endocannabinoid regulation of synaptic inhibition in the rat BLA. Glucocorticoid application to amygdala slices elicited a rapid, nonreversible suppression of spontaneous, but not evoked, GABAergic synaptic currents in BLA principal neurons; the effect was also seen with a membrane-impermeant glucocorticoid, but not with intracellular glucocorticoid application, implicating a membrane-associated glucocorticoid receptor. The glucocorticoid suppression of GABA currents was not blocked by antagonists of nuclear corticosteroid receptors, or by inhibitors of gene transcription or protein synthesis, but was blocked by inhibiting postsynaptic G-protein activity, suggesting a postsynaptic nongenomic steroid signaling mechanism that stimulates the release of a retrograde messenger. The rapid glucocorticoid-induced suppression of inhibition was prevented by blocking CB1 receptors and 2-arachidonoylglycerol (2-AG) synthesis, and it was mimicked and occluded by CB1 receptor agonists, indicating it was mediated by the retrograde release of the endocannabinoid 2-AG. The rapid glucocorticoid effect in BLA neurons in vitro was occluded by prior in vivo acute stress-induced, or prior in vitro glucocorticoid-induced, release of endocannabinoid. Acute stress also caused an increase in anxiety-like behavior that was attenuated by blocking CB1 receptor activation and inhibiting 2-AG synthesis in the BLA. Together, these findings suggest that acute stress causes a long-lasting suppression of synaptic inhibition in BLA neurons via a membrane glucocorticoid receptor-induced release of 2-AG at GABA synapses, which contributes to stress-induced anxiogenesis. We provide a cellular mechanism in the basolateral amygdala (BLA) for the rapid stress

  4. In vitro effect of Δ9-tetrahydrocannabinol to stimulate somatostatin release and block that of luteinizing hormone-releasing hormone by suppression of the release of prostaglandin E2

    International Nuclear Information System (INIS)

    Rettori, V.; Aguila, M.C.; McCann, S.M.; Gimeno, M.F.; Franchi, A.M.

    1990-01-01

    Previous in vivo studies have shown that Δ 9 -tetrahydrocannabinol (THC), the principal active ingredient in marijuana, can suppress both luteinizing hormone (LH) and growth hormone (GH) secretion after its injection into the third ventricle of conscious male rats. The present studies were deigned to determine the mechanism of these effects. Various doses of THC were incubated with either stalk median eminence fragments (MEs) or mediobasal hypothalamic (MBH) fragments in vitro. Although THC (10 nM) did not alter basal release of LH-releasing hormone (LHRH) from MEs in vitro, it completely blocked the stimulatory action of dopamine or nonrepinephrine on LHRH release. The effective doses to block LHRH release were associated with a blockade of synthesis and release of prostaglandin E 2 (PGE 2 ) from MBH in vitro. In contrast to the suppressive effect of THC on LHRH release, somatostatin release from MEs was enhanced in a dose-related manner with a minimal effective dose of 1 nM. Since PGE 2 suppresses somatostatin release, this enhancement may also be related to the suppressive effect of THC on PGE 2 synthesis and release. The authors speculate that these actions are mediated by the recently discovered THC receptors in the tissue. The results indicate that the suppressive effect of THC on LH release is mediated by a blockade of LHRH release, whereas the suppressive effect of the compound on growth hormone release is mediated, at least in part, by a stimulation of somatostatin release

  5. Suppression of grasshopper sound production by nitric oxide-releasing neurons of the central complex

    Science.gov (United States)

    Weinrich, Anja; Kunst, Michael; Wirmer, Andrea; Holstein, Gay R.

    2008-01-01

    The central complex of acridid grasshoppers integrates sensory information pertinent to reproduction-related acoustic communication. Activation of nitric oxide (NO)/cyclic GMP-signaling by injection of NO donors into the central complex of restrained Chorthippus biguttulus females suppresses muscarine-stimulated sound production. In contrast, sound production is released by aminoguanidine (AG)-mediated inhibition of nitric oxide synthase (NOS) in the central body, suggesting a basal release of NO that suppresses singing in this situation. Using anti-citrulline immunocytochemistry to detect recent NO production, subtypes of columnar neurons with somata located in the pars intercerebralis and tangential neurons with somata in the ventro-median protocerebrum were distinctly labeled. Their arborizations in the central body upper division overlap with expression patterns for NOS and with the site of injection where NO donors suppress sound production. Systemic application of AG increases the responsiveness of unrestrained females to male calling songs. Identical treatment with the NOS inhibitor that increased male song-stimulated sound production in females induced a marked reduction of citrulline accumulation in central complex columnar and tangential neurons. We conclude that behavioral situations that are unfavorable for sound production (like being restrained) activate NOS-expressing central body neurons to release NO and elevate the behavioral threshold for sound production in female grasshoppers. PMID:18574586

  6. Suppressed eye growth following diffuser removal from myopic birds is not due to increased dopamine release

    International Nuclear Information System (INIS)

    Morgan, I.; Boelen, M.; Megaw, P.; Miethke, P.

    2001-01-01

    Full text: Myopia can be induced in developing chickens by fitting a diffuser over the eye. If the diffuser is removed, the restoration of normal visual input results in rapid suppression of eye growth, with ultimate restoration of normal vision. We have investigated whether the suppression of eye growth after the removal of a diffuser from a myopic eye results from an increased rate of release of dopamine from the retina. Chickens were maintained on a 12:12 light-dark cycle, and were fitted with a diffuser from day 7 to day 21. After removal of the diffuser, the rate of dopamine release was then followed by measuring the kinetics of accumulation of DOPAC in the vitreous during the light phase. The rate of scleral glycosaminoglycan synthesis (SGS) was followed by measuring the rate of incorporation of 35 S-sulphate into scleral buttons incubated in vitro. At the end of the period of development of form-deprivation myopia,dopamine release rates were very low in the myopic eyes compared to those in the contralateral control eyes. In contrast, SGS rates were higher in the sclera from myopic eyes. After removal of the diffusers, the rate of SGS declined rapidly to below that in the control eyes within 72h. In contrast, dopamine release rates remained low for up to 10 days after removal of the occluders. These results show that there is a correlation between reduced dopamine release and increased SGS during the development of myopia, but that there is not a symmetrical relationship during the suppression of SGS following occluder removal. These results therefore suggest that dopamine is not a crucial signalling molecule in the visually mediated control of eye growth. Copyright (2001) Australian Neuroscience Society

  7. Subtype-specific suppression of Shiga toxin 2 released from Escherichia coli upon exposure to protein synthesis inhibitors

    DEFF Research Database (Denmark)

    Pedersen, Malene Gantzhorn; Hansen, Claus; Riise, Erik

    2008-01-01

    Shiga toxins (Stx) are important virulence factors in the pathogenesis of severe disease including hemolytic-uremic syndrome, caused by Stx-producing Escherichia coli (STEC). STEC strains increase the release of Stx in vitro following the addition of fluoroquinolones, whereas protein synthesis...... inhibitors previously have been reported to suppress the release of Stx. The amount of Stx released from wild-type STEC strains incubated with protein synthesis inhibitors was examined by a Vero cell cytotoxicity assay. The amounts released were compared to the Stx type (Stx1 or Stx2) and additionally...... to the individual subtypes and toxin variants of Stx2. In general, Stx2 release was suppressed significantly upon exposure to protein synthesis inhibitors at MICs, which was not observed in the case of Stx1. Also, the average amount of different Stx2 toxin variants released was suppressed to various levels ranging...

  8. Surface obstacles in pulsatile flow

    Science.gov (United States)

    Carr, Ian A.; Plesniak, Michael W.

    2017-11-01

    Flows past obstacles mounted on flat surfaces have been widely studied due to their ubiquity in nature and engineering. For nearly all of these studies, the freestream flow over the obstacle was steady, i.e., constant velocity, unidirectional flow. Unsteady, pulsatile flows occur frequently in biology, geophysics, biomedical engineering, etc. Our study is aimed at extending the comprehensive knowledge base that exists for steady flows to considerably more complex pulsatile flows. Characterizing the vortex and wake dynamics of flows around surface obstacles embedded in pulsatile flows can provide insights into the underlying physics in all wake and junction flows. In this study, we experimentally investigate the wake of two canonical obstacles: a cube and a circular cylinder with an aspect ratio of unity. Our previous studies of a surface-mounted hemisphere in pulsatile flow are used as a baseline for these two new, more complex geometries. Phase-averaged PIV and hot-wire anemometry are used to characterize the dynamics of coherent structures in the wake and at the windward junction of the obstacles. Complex physics occur during the deceleration phase of the pulsatile inflow. We propose a framework for understanding these physics based on self-induced vortex propagation, similar to the phenomena exhibited by vortex rings.

  9. A neurokinin 3 receptor-selective agonist accelerates pulsatile luteinizing hormone secretion in lactating cattle.

    Science.gov (United States)

    Nakamura, Sho; Wakabayashi, Yoshihiro; Yamamura, Takashi; Ohkura, Satoshi; Matsuyama, Shuichi

    2017-07-01

    Pulsatile gonadotropin-releasing hormone (GnRH) secretion, which is indispensable for follicular development, is suppressed in lactating dairy and beef cattle. Neurokinin B (NKB) neurons in the arcuate nucleus of the hypothalamus are considered to play an essential role in generating the pulsatile mode of GnRH/luteinizing hormone (LH) secretion. The present study aimed to clarify the role of NKB-neurokinin 3 receptor (NK3R) signaling in the pulsatile pattern of GnRH/gonadotropin secretion in postpartum lactating cattle. We examined the effects of the administration of an NK3R-selective agonist, senktide, on gonadotropin secretion in lactating cattle. The lactating cattle, at approximately 7 days postpartum, were intravenously infused with senktide (30 or 300 nmol/min) or vehicle for 24 h. The administration of 30 or 300 nmol/min senktide significantly increased LH pulse frequency compared to in the control group during 0-4 or 20-24 h after infusion, respectively. Moreover, LH and follicle-stimulating hormone levels were gradually increased by 300 nmol/min administration of senktide during the 0-4-h sampling period. Ultrasonography of the ovaries was performed to identify the first postpartum ovulation in senktide-administered lactating cattle. The interval from calving to first postpartum ovulation was significantly shorter in the 300 nmol/min senktide-administered group than in the control group. Taken together, these findings suggest that senktide infusion elicits an increase in LH pulse frequency that may stimulate follicular development and, in turn, induce the first postpartum ovulation in lactating cattle. © The Authors 2017. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Kisspeptin and LH pulsatile temporal coupling in PCOS patients.

    Science.gov (United States)

    Katulski, Krzysztof; Podfigurna, Agnieszka; Czyzyk, Adam; Meczekalski, Blazej; Genazzani, Alessandro D

    2018-05-04

    To evaluate the temporal coupling between spontaneous kisspeptin and luteinizing hormone (LH) pulsatile releases in polycystic ovary syndrome (PCOS) patients. We examined 71 patients diagnosed with PCOS. A 2 h pulsatility study was performed to evaluate serum kisspeptin and LH pulse frequency and concentration, sampled every 10 min; baseline follicle-stimulating hormone (FSH), estradiol (E2), prolactin (PRL), cortisol, 17-hydroksy-progesterone (17OHP), testosterone (T), free testosterone index (FTI, and insulin levels were also measured. Detect and Specific Concordance (SC) algorithms were used to evaluate the temporal coupling associations between spontaneous episodic secretion of kisspeptin and LH. All PCOS patients demonstrated LH and kisspeptin pulsatile secretions. When the SC index was calculated across the sample of PCOS patients (n = 71), no temporal coupling was observed between kisspeptin and LH pulses. When PCOS patients were subdivided according to their menstrual cyclicity, oligomenorrheic patients demonstrated elevated kisspeptin pulse frequency. Additionally, the SC index reveled a temporal coupling between kisspeptin and LH secretory peaks only in eumenorrheic patients (n = 30, intermenstrual interval PCOS patients (intermenstrual interval > 45 days) did not demonstrate temporal coupling between kisspeptin and LH secretory peaks. The study of the endogenous kisspeptin and LH pulsatile release revealed the temporal coupling of kisspeptin with LH secretory pulses only in eumenorrheic. This data supports the hypothesis that neuroendocrine impairments in PCOS affect the coupling of kisspeptin with LH pulses and potentially worsen as the disease progresses, becoming unequivocally evident in oligomenorrheic PCOS patients.

  11. In vitro effect of. Delta. sup 9 -tetrahydrocannabinol to stimulate somatostatin release and block that of luteinizing hormone-releasing hormone by suppression of the release of prostaglandin E sub 2

    Energy Technology Data Exchange (ETDEWEB)

    Rettori, V.; Aguila, M.C.; McCann, S.M. (Univ. of Texas Southwestern Medical Center at Dallas (United States)); Gimeno, M.F.; Franchi, A.M. (Centro de Estudios Farmacologicos y de Principios Naturales, Buenos Aires (Argentina))

    1990-12-01

    Previous in vivo studies have shown that {Delta}{sup 9}-tetrahydrocannabinol (THC), the principal active ingredient in marijuana, can suppress both luteinizing hormone (LH) and growth hormone (GH) secretion after its injection into the third ventricle of conscious male rats. The present studies were deigned to determine the mechanism of these effects. Various doses of THC were incubated with either stalk median eminence fragments (MEs) or mediobasal hypothalamic (MBH) fragments in vitro. Although THC (10 nM) did not alter basal release of LH-releasing hormone (LHRH) from MEs in vitro, it completely blocked the stimulatory action of dopamine or nonrepinephrine on LHRH release. The effective doses to block LHRH release were associated with a blockade of synthesis and release of prostaglandin E{sub 2} (PGE{sub 2}) from MBH in vitro. In contrast to the suppressive effect of THC on LHRH release, somatostatin release from MEs was enhanced in a dose-related manner with a minimal effective dose of 1 nM. Since PGE{sub 2} suppresses somatostatin release, this enhancement may also be related to the suppressive effect of THC on PGE{sub 2} synthesis and release. The authors speculate that these actions are mediated by the recently discovered THC receptors in the tissue. The results indicate that the suppressive effect of THC on LH release is mediated by a blockade of LHRH release, whereas the suppressive effect of the compound on growth hormone release is mediated, at least in part, by a stimulation of somatostatin release.

  12. Hypersensitivity reaction with intravenous GnRH after pulsatile subcutaneous GnRH treatment in male hypogonadotrophic hypogonadism.

    OpenAIRE

    Popović, V.; Milosević, Z.; Djukanović, R.; Micić, D.; Nesović, M.; Manojlović, D.; Djordjević, P.; Mićić, J.

    1988-01-01

    Chronic pulsatile subcutaneous administration of low doses of gonadotrophin releasing hormone (GnRH) is an effective therapy for men with hypogonadotrophic hypogonadism. Hypersensitivity reactions to GnRH are rare. We wish to report hypersensitivity reactions with intravenous GnRH after low dose subcutaneous pulsatile GnRH treatment in two men with hypogonadotrophic hypogonadism due to suprasellar disease.

  13. Recent Advancement and Technological Aspects of Pulsatile Drug Delivery System - A Laconic Review.

    Science.gov (United States)

    Pandit, Vinay; Kumar, Ajay; Ashawat, Mahendra S; Verma, Chander P; Kumar, Pravin

    2017-01-01

    Pulsatile drug delivery system (PDDS) shows potential significance in the field of drug delivery to release the maximum amount of drug at a definite site and at specific time. PDDS are mainly time controlled delivery devices having a definite pause period for drug release, which is not affected by acidity, alkalinity, motility and enzymes present in the gastrointestinal tract. Pulsatile medication possess the potential to deliver the drugs in the therapy of diseases where drug dose is essential during sleep, drugs having greater first pass metabolism and absorption at precise location in digestive tract. The review article, discuss the general concepts, marketed formulations and patents or any other recent advancement in pulsatile release technology. It also highlights on diseases requiring therapy by pulsatile release, various researches on herbal pulsatile formulations and quality control aspects of PDDS. Pulsatile medication possess the potential to deliver the drugs in the therapy of diseases where drug dose is essential during sleep, drugs having greater first pass metabolism and absorption at precise location in digestive tract. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  14. The cauliflower Orange gene enhances petiole elongation by suppressing expression of eukaryotic release factor 1.

    Science.gov (United States)

    Zhou, Xiangjun; Sun, Tian-Hu; Wang, Ning; Ling, Hong-Qing; Lu, Shan; Li, Li

    2011-04-01

    The cauliflower (Brassica oleracea var. botrytis) Orange (Or) gene affects plant growth and development in addition to conferring β-carotene accumulation. This study was undertaken to investigate the molecular basis for the effects of the Or gene mutation in on plant growth. The OR protein was found to interact with cauliflower and Arabidopsis eukaryotic release factor 1-2 (eRF1-2), a member of the eRF1 family, by yeast two-hybrid analysis and by bimolecular fluorescence complementation (BiFC) assay. Concomitantly, the Or mutant showed reduced expression of the BoeRF1 family genes. Transgenic cauliflower plants with suppressed expression of BoeRF1-2 and BoeRF1-3 were generated by RNA interference. Like the Or mutant, the BoeRF1 RNAi lines showed increased elongation of the leaf petiole. This long-petiole phenotype was largely caused by enhanced cell elongation, which resulted from increased cell length and elevated expression of genes involved in cell-wall loosening. These findings demonstrate that the cauliflower Or gene controls petiole elongation by suppressing the expression of eRF1 genes, and provide new insights into the molecular mechanism of leaf petiole regulation. © 2010 The Authors. New Phytologist © 2010 New Phytologist Trust.

  15. Extended Release of an Anti–Heparan Sulfate Peptide From a Contact Lens Suppresses Corneal Herpes Simplex Virus-1 Infection

    Science.gov (United States)

    Jaishankar, Dinesh; Buhrman, Jason S.; Valyi-Nagy, Tibor; Gemeinhart, Richard A.; Shukla, Deepak

    2016-01-01

    Purpose To prolong the release of a heparan sulfate binding peptide, G2-C, using a commercially available contact lens as a delivery vehicle and to demonstrate the ability of the released peptide to block herpes simplex virus-1 (HSV-1) infection using in vitro, ex vivo, and in vivo models of corneal HSV-1 infection. Methods Commercially available contact lenses were immersed in peptide solution for 5 days prior to determining the release of the peptide at various time points. Cytotoxicity of the released samples was determined by MTT and cell cycle analysis, and the functional activity of the released samples were assessed by viral entry, and viral spread assay using human corneal epithelial cells (HCE). The ability to suppress infection in human and pig cornea ex vivo and mouse in vivo models were also assessed. Results Peptide G2-C was released through the contact lens. Following release for 3 days, the peptide showed significant activity by inhibiting HSV-1 viral entry and spread in HCE cells. Significant suppression of infection was also observed in the ex vivo and in vivo experiments involving corneas. Conclusions Extended release of an anti–HS peptide through a commercially available contact lens can generate significant anti–HSV-1 activity and provides a new and effective way to control corneal herpes. PMID:26780322

  16. Effect of corticotropin-releasing factor receptor antagonist on psychologically suppressed masculine sexual behavior in rats.

    Science.gov (United States)

    Miwa, Yoshiji; Nagase, Keiko; Oyama, Nobuyuki; Akino, Hironobu; Yokoyama, Osamu

    2011-03-01

    Corticotropin-releasing factor (CRF) coordinates various responses of the body to stress, and CRF receptors are important targets of treatment for stress-related disorders. To investigate the effect of a nonselective CRF receptor antagonist, astressin, on suppression of masculine sexual behavior by psychological stress in rats. First, we investigated the influence of psychological stress, induced 2 hours per day for three consecutive days, on sexual behavior. Then, rats were divided into 4 groups: a control group, an astressin administration group (A), a psychological stress loading group (PS), and a psychological stress loading and astressin administration group (PS + A). The rats were exposed to sham or psychological stress for three consecutive days. After the last stress loading, the rats were injected with vehicle or astressin, and their sexual behavior was observed. We also measured serum levels of adrenocorticotropic hormone (ACTH). The effects of astressin on sexual behavior and serum levels of ACTH in rats affected by psychological stress were determined. Sexual behavior was reduced after psychological stress loading. The PS rats had significantly longer mount, intromission, and ejaculation latencies and lower ejaculation frequency than did the control, A, and PS + A rats. The intromission latency and ejaculation frequency in the PS + A rats did not achieve the level observed in the controls. There was no significant difference in these parameters between the control and A rats. Serum ACTH levels were significantly lower in PS + A rats than in PS rats. Psychologically suppressed masculine sexual behavior could be partially recovered with astressin administration in rats. These data provide a rationale for the further study of CRF receptor antagonists as novel agents for treating psychological sexual disorders. © 2010 International Society for Sexual Medicine.

  17. Rehabilitation of Understocked Loblolly-Shortleaf Pine Stands - II. Development of Intermediate and Suppressed Trees Following Release in Natural Stands

    Science.gov (United States)

    James B. Baker; Michael G. Shelton

    1998-01-01

    Development of 86 intermediate and suppressed loblolly pine (Pinus taeda L.) trees, that had been recently released from overtopping pines and hardwoods, was monitored over a 15 year period. The trees were growing in natural stands on good sites (site index = 90 ft at 50 years) that had been recently cut to stocking levels ranging from 10 to 50 percent. At time of...

  18. Curcumin suppression of cytokine release and cytokine storm. A potential therapy for patients with Ebola and other severe viral infections.

    Science.gov (United States)

    Sordillo, Peter P; Helson, Lawrence

    2015-01-01

    The terminal stage of Ebola and other viral diseases is often the onset of a cytokine storm, the massive overproduction of cytokines by the body's immune system. The actions of curcumin in suppressing cytokine release and cytokine storm are discussed. Curcumin blocks cytokine release, most importantly the key pro-inflammatory cytokines, interleukin-1, interleukin-6 and tumor necrosis factor-α. The suppression of cytokine release by curcumin correlates with clinical improvement in experimental models of disease conditions where a cytokine storm plays a significant role in mortality. The use of curcumin should be investigated in patients with Ebola and cytokine storm. Intravenous formulations may allow achievement of therapeutic blood levels of curcumin. Copyright © 2015 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved.

  19. Rosiglitazone Suppresses In Vitro Seizures in Hippocampal Slice by Inhibiting Presynaptic Glutamate Release in a Model of Temporal Lobe Epilepsy.

    Directory of Open Access Journals (Sweden)

    Shi-Bing Wong

    Full Text Available Peroxisomal proliferator-activated receptor gamma (PPARγ is a nuclear hormone receptor whose agonist, rosiglitazone has a neuroprotective effect to hippocampal neurons in pilocarpine-induced seizures. Hippocampal slice preparations treated in Mg2+ free medium can induce ictal and interictal-like epileptiform discharges, which is regarded as an in vitro model of N-methyl-D-aspartate (NMDA receptor-mediated temporal lobe epilepsy (TLE. We applied rosiglitazone in hippocampal slices treated in Mg2+ free medium. The effects of rosiglitazone on hippocampal CA1-Schaffer collateral synaptic transmission were tested. We also examined the neuroprotective effect of rosiglitazone toward NMDA excitotoxicity on cultured hippocampal slices. Application of 10 μM rosiglitazone significantly suppressed amplitude and frequency of epileptiform discharges in CA1 neurons. Pretreatment with the PPARγ antagonist GW9662 did not block the effect of rosiglitazone on suppressing discharge frequency, but reverse the effect on suppressing discharge amplitude. Application of rosiglitazone suppressed synaptic transmission in the CA1-Schaffer collateral pathway. By miniature excitatory-potential synaptic current (mEPSC analysis, rosiglitazone significantly suppressed presynaptic neurotransmitter release. This phenomenon can be reversed by pretreating PPARγ antagonist GW9662. Also, rosiglitazone protected cultured hippocampal slices from NMDA-induced excitotoxicity. The protective effect of 10 μM rosiglitazone was partially antagonized by concomitant high dose GW9662 treatment, indicating that this effect is partially mediated by PPARγ receptors. In conclusion, rosiglitazone suppressed NMDA receptor-mediated epileptiform discharges by inhibition of presynaptic neurotransmitter release. Rosiglitazone protected hippocampal slice from NMDA excitotoxicity partially by PPARγ activation. We suggest that rosiglitazone could be a potential agent to treat patients with TLE.

  20. Luteinizing hormone pulsatility in females following radiation therapy for central nervous system malignancies

    International Nuclear Information System (INIS)

    Brasacchio, R.A.; Constine, L.S.; Woolf, P.; Raubertas, R.F.; Veldhuis, J.D.; Muhs, A.G.

    1997-01-01

    Purpose: Females incidentally irradiated to the hypothalamic-pituitary axis (H/P-A) during radiation therapy (RT) for brain tumors may become oligoamenorrheic. We previously demonstrated that these women are hypoestrogenemic but frequently have near normal or only moderately decreased basal luteinizing hormone (LH) levels and maintain appropriate peak pituitary responses to exogenous gonadotropin releasing hormone (GnRH). We postulated that hypothalamic injury resulting in abnormal LH pulsatility could explain this complex of findings. This investigation intended to characterize this hypothalamic injury and test two potentially corrective pharmacologic interventions. Catecholamines (specifically dopamine) and opiates are known to suppress pituitary LH release through inhibition of the pituitary gonadotropes or of the GnRH neuronal terminals in the hypothalamus. Radiation-induced dysfunction of the catecholaminergic or opiate control mechanisms might translate into an increase in dopamine or opiate release or receptor responsiveness, which in turn would inhibit pulsatile gonadotropin secretion, leading to reduced LH pulsatility and to gonadal dysfunction. We therefore determined the pattern of LH release in normal controls and in patients, at baseline as well as after administration of the dopamine receptor antagonist metoclopramide (MCP), and the opiate-receptor antagonist naloxone (NAL). Methods: Patient eligibility criteria included RT to the H/P-A for a non-H/P-A CNS tumor, usually astrocytoma, with subsequent hypoestrogenemia and oligo-amenorrhea. Patients and normal volunteers were studied first under control conditions and then using MCP and NAL in a randomized cross-over manner at monthly intervals. Serum samples for LH determination were taken every 10 minutes for 12 hours during an overnight hospital stay. MCP (10 mg) was administered as an IV bolus every 4.5 hours, and NAL was administered as a continuous infusion (1.6 mg/hour). The following morning each

  1. 21 CFR 870.4320 - Cardiopulmonary bypass pulsatile flow generator.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass pulsatile flow generator... Cardiopulmonary bypass pulsatile flow generator. (a) Identification. A cardiopulmonary bypass pulsatile flow generator is an electrically and pneumatically operated device used to create pulsatile blood flow. The...

  2. Retention on buprenorphine is associated with high levels of maximal viral suppression among HIV-infected opioid dependent released prisoners.

    Directory of Open Access Journals (Sweden)

    Sandra A Springer

    Full Text Available HIV-infected prisoners lose viral suppression within the 12 weeks after release to the community. This prospective study evaluates the use of buprenorphine/naloxone (BPN/NLX as a method to reduce relapse to opioid use and sustain viral suppression among released HIV-infected prisoners meeting criteria for opioid dependence (OD.From 2005-2010, 94 subjects meeting DSM-IV criteria for OD were recruited from a 24-week prospective trial of directly administered antiretroviral therapy (DAART for released HIV-infected prisoners; 50 (53% selected BPN/NLX and were eligible to receive it for 6 months; the remaining 44 (47% selected no BPN/NLX therapy. Maximum viral suppression (MVS, defined as HIV-1 RNA<50 copies/mL, was compared for the BPN/NLX and non-BPN/NLX (N = 44 groups.The two groups were similar, except the BPN/NLX group was significantly more likely to be Hispanic (56.0% v 20.4%, from Hartford (74.4% v 47.7% and have higher mean global health quality of life indicator scores (54.18 v 51.40. MVS after 24 weeks of being released was statistically correlated with 24-week retention on BPN/NLX [AOR = 5.37 (1.15, 25.1], having MVS at the time of prison-release [AOR = 10.5 (3.21, 34.1] and negatively with being Black [AOR = 0.13 (0.03, 0.68]. Receiving DAART or methadone did not correlate with MVS.In recognition that OD is a chronic relapsing disease, strategies that initiate and retain HIV-infected prisoners with OD on BPN/NLX is an important strategy for improving HIV treatment outcomes as a community transition strategy.

  3. Investigation of the pulsatile pipe flow

    Czech Academy of Sciences Publication Activity Database

    Adamec, J.; Nožička, J.; Kořenář, Josef

    2000-01-01

    Roč. 18, č. 2 (2000), s. 17-22 ISSN 0392-8764 Institutional research plan: CEZ:AV0Z2060917 Keywords : pulsatile flow * laminar-turbulent transition * reynolds normal stress Subject RIV: BK - Fluid Dynamics

  4. AN OVERVIEW ON PULSATILE FLOW DYNAMICS

    OpenAIRE

    Çarpinlioğlu, Melda Özdinç

    2015-01-01

    Pulsatile flow dynamics in reference to the relevant experimental research on the manner between the time periods of 1997- 2015 is presented in this paper. The flow field under discussion is generated through a rigid circular cross-sectional pipe as an axial slightly- compressible and sinusoidal one in a controlled range of the oscillation parameters. Laminar and turbulent flow regimes are considered with a particular emphasis devoted to the transitional characteristics of laminar pulsatile f...

  5. Neural processes mediating the preparation and release of focal motor output are suppressed or absent during imagined movement

    Science.gov (United States)

    Eagles, Jeremy S.; Carlsen, Anthony N.

    2016-01-01

    Movements that are executed or imagined activate a similar subset of cortical regions, but the extent to which this activity represents functionally equivalent neural processes is unclear. During preparation for an executed movement, presentation of a startling acoustic stimulus (SAS) evokes a premature release of the planned movement with the spatial and temporal features of the tasks essentially intact. If imagined movement incorporates the same preparatory processes as executed movement, then a SAS should release the planned movement during preparation. This hypothesis was tested using an instructed-delay cueing paradigm during which subjects were required to rapidly release a handheld weight while maintaining the posture of the arm or to perform first-person imagery of the same task while holding the weight. In a subset of trials, a SAS was presented at 1500, 500, or 200 ms prior to the release cue. Task-appropriate preparation during executed and imagined movements was confirmed by electroencephalographic recording of a contingent negative variation waveform. During preparation for executed movement, a SAS often resulted in premature release of the weight with the probability of release progressively increasing from 24 % at −1500 ms to 80 % at −200 ms. In contrast, the SAS rarely (movement. However, the SAS frequently evoked the planned postural response (suppression of bicep brachii muscle activity) irrespective of the task or timing of stimulation (even during periods of postural hold without preparation). These findings provide evidence that neural processes mediating the preparation and release of the focal motor task (release of the weight) are markedly attenuated or absent during imagined movement and that postural and focal components of the task are prepared independently. PMID:25744055

  6. Oral contraceptive therapy for polycystic ovary disease after chronic gonadotropin-releasing agonist administration. Predictors of continued ovarian suppression.

    Science.gov (United States)

    Elkind-Hirsch, K E; Anania, C; Malinak, R

    1996-09-01

    To study the beneficial effects of oral contraceptive (OC) therapy following gonadotropin-releasing hormone agonist (GnRH-a) administration in women with polycystic ovary disease (PCOD). Twenty-three hyperandrogenic women (aged 15-39) were randomized into two groups; GnRH-a (depot every 28 days) for six months or combination therapy (GnRH-a plus OC "addback") for six months. Following six months of treatment with either therapy, all patients received OC therapy for at least six months. The hormonal state was evaluated at three-month intervals. Hormone levels of luteinizing hormone (LH), testosterone (T) and free T remained suppressed within the normal range in 11 of 17 patients (65%) during the six months of OC only therapy, while the other six patients showed "escape" from suppression, with the LH, T and free T concentrations rising to pre-GnRH-a treatment levels. Use of OC addback therapy did not potentiate the long-acting therapeutic effect of GnRH-a pretreatment; three of six patients in the escape group were pretreated with combination therapy and three with GnRH-a only. In the majority of women with PCOD, OC therapy following GnRH-a administration was effective in maintaining ovarian androgen suppression. Failure to maintain ovarian suppression in this patient population was associated with higher elevations of baseline free T concentrations.

  7. Suppressed histamine release from rat peritoneal mast cells by ultraviolet B irradiation: decreased diacylglycerol formation as a possible mechanism

    International Nuclear Information System (INIS)

    Danno, K.; Fujii, K.; Tachibana, T.; Toda, K.; Horio, T.

    1988-01-01

    This study was designed to investigate the effect of ultraviolet B (UVB) irradiation on mast cell functions. Purified mast cells obtained from rat peritoneal cavity were irradiated with UVB and subsequently exposed to a degranulator, compound 48/80, or the calcium ionophore A-23187. The amount of histamine released from mast cells measured by the enzyme isotopic assay was significantly decreased by UVB irradiation (100-400 mJ/cm2). Within this dose range, UVB alone was not cytotoxic to the cells because it did not induce histamine release. The suppression was observed when mast cells were subjected to degranulation without intervals after UVB irradiation, and even after 5 h postirradiation. The wavelength of 300 nm from a monochromatic light source showed the maximum effect. When mast cells prelabeled with [ 3 H]arachidonate were irradiated and challenged by compound 48/80, label accumulation in diacylglycerol produced by the phosphatidylinositol cycle was considerably decreased by UVB irradiation. From these results, we hypothesize that, within an adequate irradiation dose, UVB irradiation suppresses histamine release from mast cells, probably by causing noncytotoxic damage to the membrane phospholipid metabolism, which is tied to the degranulation mechanisms

  8. Estradiol-Dependent Stimulation and Suppression of Gonadotropin-Releasing Hormone Neuron Firing Activity by Corticotropin-Releasing Hormone in Female Mice.

    Science.gov (United States)

    Phumsatitpong, Chayarndorn; Moenter, Suzanne M

    2018-01-01

    Gonadotropin-releasing hormone (GnRH) neurons are the final central regulators of reproduction, integrating various inputs that modulate fertility. Stress typically inhibits reproduction but can be stimulatory; stress effects can also be modulated by steroid milieu. Corticotropin-releasing hormone (CRH) released during the stress response may suppress reproduction independent of downstream glucocorticoids. We hypothesized CRH suppresses fertility by decreasing GnRH neuron firing activity. To test this, mice were ovariectomized (OVX) and either implanted with an estradiol capsule (OVX+E) or not treated further to examine the influence of estradiol on GnRH neuron response to CRH. Targeted extracellular recordings were used to record firing activity from green fluorescent protein-identified GnRH neurons in brain slices before and during CRH treatment; recordings were done in the afternoon when estradiol has a positive feedback effect to increase GnRH neuron firing. In OVX mice, CRH did not affect the firing rate of GnRH neurons. In contrast, CRH exhibited dose-dependent stimulatory (30 nM) or inhibitory (100 nM) effects on GnRH neuron firing activity in OVX+E mice; both effects were reversible. The dose-dependent effects of CRH appear to result from activation of different receptor populations; a CRH receptor type-1 agonist increased firing activity in GnRH neurons, whereas a CRH receptor type-2 agonist decreased firing activity. CRH and specific agonists also differentially regulated short-term burst frequency and burst properties, including burst duration, spikes/burst, and/or intraburst interval. These results indicate that CRH alters GnRH neuron activity and that estradiol is required for CRH to exert both stimulatory and inhibitory effects on GnRH neurons. Copyright © 2018 Endocrine Society.

  9. Exposure of alveolar macrophages to polybrominated diphenyl ethers suppresses the release of pro-inflammatory products in vitro.

    Science.gov (United States)

    Hennigar, Stephen R; Myers, Jay L; Tagliaferro, Anthony R

    2012-04-01

    Inhalation of chemical pollutants has been associated with a reduced immune response in humans. Inhalation of dust is a major route of exposure for one endocrine-disrupting chemical and suspected xenoestrogen, polybrominated diphenyl ethers (PBDEs); however, the impact of PBDEs on immune function is unclear. The objective of this study was to investigate the action of PBDEs on cytokine and eicosanoid release by alveolar macrophages and determine whether the effects are mediated via the estrogen receptor. The production of tumor necrosis factor (TNF)-α, interleukin (IL)-6, IL-1β, IL-10 and prostaglandin E(2) (PGE(2)) by porcine alveolar macrophages exposed to different concentrations of the pentabrominated diphenyl ether mixture, DE-71, were measured; cells were also exposed to varying concentrations of 17β-estradiol and the selective estrogen receptor-modulating agent, tamoxifen. Cells exposed to PBDEs released significantly less pro-inflammatory cytokines (TNF-α and IL-6) and PGE(2) compared with controls; IL-1β and IL-10 were not detected in the culture medium. Cells exposed to 17β-estradiol released significantly less TNF-α compared with controls, an effect that was reversed by the addition of tamoxifen; tamoxifen had no effect on the inhibition of TNF-α release by PBDEs. Although the suppression of TNF-α with DE-71 was similar to that of estrogen, the inhibitory effects of DE-71 were not found to be dependent on the estrogen receptor. Findings of this study suggest that chronic exposure to PBDEs suppressed innate immunity in vitro. Whether the immunosuppressant effects of PBDEs occur in vivo, remains to be determined.

  10. Suppressed Release of Clarithromycin from Tablets by Crystalline Phase Transition of Metastable Polymorph Form I.

    Science.gov (United States)

    Fujiki, Sadahiro; Watanabe, Narumi; Iwao, Yasunori; Noguchi, Shuji; Mizoguchi, Midori; Iwamura, Takeru; Itai, Shigeru

    2015-08-01

    The pharmaceutical properties of clarithromycin (CAM) tablets containing the metastable form I of crystalline CAM were investigated. Although the dissolution rate of form I was higher than that of stable form II, the release of CAM from form I tablet was delayed. Disintegration test and liquid penetration test showed that the disintegration of the tablet delayed because of the slow penetration of an external solution into form I tablet. Investigation by scanning electron microscopy revealed that the surface of form I tablet was covered with fine needle-shaped crystals following an exposure to the external solution. These crystals were identified as form IV crystals by powder X-ray diffraction. The phenomenon that CAM releases from tablet was inhibited by fine crystals spontaneously formed on the tablet surface could be applied to the design of sustained-release formulation systems with high CAM contents by minimizing the amount of functional excipients. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.

  11. Spermidine Suppresses Age-Associated Memory Impairment by Preventing Adverse Increase of Presynaptic Active Zone Size and Release.

    Directory of Open Access Journals (Sweden)

    Varun K Gupta

    2016-09-01

    Full Text Available Memories are assumed to be formed by sets of synapses changing their structural or functional performance. The efficacy of forming new memories declines with advancing age, but the synaptic changes underlying age-induced memory impairment remain poorly understood. Recently, we found spermidine feeding to specifically suppress age-dependent impairments in forming olfactory memories, providing a mean to search for synaptic changes involved in age-dependent memory impairment. Here, we show that a specific synaptic compartment, the presynaptic active zone (AZ, increases the size of its ultrastructural elaboration and releases significantly more synaptic vesicles with advancing age. These age-induced AZ changes, however, were fully suppressed by spermidine feeding. A genetically enforced enlargement of AZ scaffolds (four gene-copies of BRP impaired memory formation in young animals. Thus, in the Drosophila nervous system, aging AZs seem to steer towards the upper limit of their operational range, limiting synaptic plasticity and contributing to impairment of memory formation. Spermidine feeding suppresses age-dependent memory impairment by counteracting these age-dependent changes directly at the synapse.

  12. Release of suppressed red spruce using canopy gap creation—Ecological restoration in the Central Appalachians

    Science.gov (United States)

    Rentch, J.S.; Ford, W. Mark; Schuler, T.S.; Palmer, J.; Diggins, Corinne A.

    2016-01-01

    Red spruce (Picea rubens) and red spruce-northern hardwood mixed stands once covered as much as 300,000 ha in the Central Appalachians, but now comprise no more than 21,000 ha. Recently, interest in restoration of this forest type has increased because red spruce forests provide habitat for a number of rare animal species. Our study reports the results of an understory red spruce release experiment in hardwood-dominated stands that have a small component of understory red spruce. In 2005, 188 target spruce were identified in sample plots at six locations in central West Virginia. We projected a vertical cylinder above the crown of all target spruces, and in 2007, we performed a release treatment whereby overtopping hardwoods were treated with herbicide using a stem injection technique. Release treatments removed 0–10% (Control), 11–50% (Low), 51–89% (Medium), and ≤90% (High) of the basal area of overtopping trees. We also took canopy photographs at the time of each remeasurement in 2007, 2010, and 2013, and compared basal removal treatments and resulting 2010 canopy openness and understory light values. The high treatment level provided significantly greater six-year dbh and height growth than the other treatment levels. Based on these results, we propose that a tree-centered release approach utilizing small canopy gaps that emulate the historical, gap-phase disturbance regime provides a good strategy for red spruce restoration in hardwood forests where overstory spruce are virtually absent, and where red spruce is largely relegated to the understory.

  13. Differential Effects of Continuous Exposure to the Investigational Metastin/Kisspeptin Analog TAK-683 on Pulsatile and Surge Mode Secretion of Luteinizing Hormone in Ovariectomized Goats

    Science.gov (United States)

    TANAKA, Tomomi; OHKURA, Satoshi; WAKABAYASHI, Yoshihiro; KUROIWA, Takenobu; NAGAI, Kiyosuke; ENDO, Natsumi; TANAKA, Akira; MATSUI, Hisanori; KUSAKA, Masami; OKAMURA, Hiroaki

    2013-01-01

    Abstract The aim of the present study was to determine if the estradiol-induced luteinizing hormone (LH) surge is influenced by the constant exposure to TAK-683, an investigational metastin/kisspeptin analog, that had been established to depress the pulsatile gonadotropin-releasing hormone (GnRH) and LH secretion in goats. Ovariectomized goats subcutaneously received TAK-683 (TAK-683 group, n=6) or vehicle (control group, n=6) constantly via subcutaneous implantation of an osmotic pump. Five days after the start of the treatment, estradiol was infused intravenously in both groups to evaluate the effects on the LH surge. Blood samples were collected at 6-min intervals for 4 h prior to the initiation of either the TAK-683 treatment or the estradiol infusion, to determine the profiles of pulsatile LH secretion. They were also collected at 2-h intervals from –4 h to 32 h after the start of estradiol infusion for analysis of LH surges. The frequency and mean concentrations of LH pulses in the TAK-683 group were remarkably suppressed 5 days after the start of TAK-683 treatment compared with those of the control group (P<0.05). On the other hand, a clear LH surge was observed in all animals of both groups. There were no significant differences in the LH concentrations for surge peak and the peak time of the LH surge between the TAK-683 and control groups. These findings suggest that the effects of continuous exposure to kisspeptin or its analog on the mechanism(s) that regulates the pulsatile and surge mode secretion of GnRH/LH are different in goats. PMID:24047956

  14. LC for analysis of two sustained-release mixtures containing cough cold suppressant drugs.

    Science.gov (United States)

    El-Gindy, Alaa; Sallam, Shehab; Abdel-Salam, Randa A

    2010-07-01

    A liquid chromatographic method was applied for the analysis of two sustained-release mixtures containing dextromethorphane hydrobromide, carbinoxamine maleate with either phenylephrine hydrochloride in pharmaceutical capsules (Mix 1) or phenyl-propanolamine, methylparaben, and propylparaben, which bonds as a drug base to ion exchange resin in pharmaceutical syrup (Mix 2). The method was used for their simultaneous determination using a CN column with a mobile phase consisting of acetonitrile-12 mM ammonium acetate in the ratio of 60:40 (v/v, pH 6.0) for Mix 1 and 45:55 (v/v, pH 6.0) for Mix 2.

  15. Suppression of the release of arsenic from arsenopyrite by carrier-microencapsulation using Ti-catechol complex.

    Science.gov (United States)

    Park, Ilhwan; Tabelin, Carlito Baltazar; Magaribuchi, Kagehiro; Seno, Kensuke; Ito, Mayumi; Hiroyoshi, Naoki

    2018-02-15

    Arsenopyrite is the most common arsenic-bearing sulfide mineral in nature, and its weathering contributes to acid mine drainage (AMD) formation and the release of toxic arsenic (As). To mitigate this problem, carrier-microencapsulation (CME) using titanium (Ti)-catechol complex (i.e., Ti-based CME) was investigated to passivate arsenopyrite by forming a protective coating. Ti 4+ ion dissolved in sulfuric acid and catechol were used to successfully synthesize Ti(IV) tris-catecholate complex, [Ti(Cat) 3 ] 2- , which was stable in the pH range of 5-12. Electrochemical studies on the redox properties of this complex indicate that its oxidative decomposition was a one-step, irreversible process. The leaching of As from arsenopyrite was suppressed by CME treatment using the synthesized Ti-catechol complex. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX) and diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) indicate that this suppression was primarily due to the formation of an anatase (β-TiO 2 )-containing coating. Based on these results, a detailed 4-step mechanism to explain the decomposition of [Ti(Cat) 3 ] 2- and formation of TiO 2 coating in Ti-based CME is proposed: (1) adsorption, (2) partial oxidation-intermediate formation, (3) non electrochemical dissociation, and (4) hydrolysis-precipitation. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Pulsatile pipe flow transition: Flow waveform effects

    Science.gov (United States)

    Brindise, Melissa C.; Vlachos, Pavlos P.

    2018-01-01

    Although transition is known to exist in various hemodynamic environments, the mechanisms that govern this flow regime and their subsequent effects on biological parameters are not well understood. Previous studies have investigated transition in pulsatile pipe flow using non-physiological sinusoidal waveforms at various Womersley numbers but have produced conflicting results, and multiple input waveform shapes have yet to be explored. In this work, we investigate the effect of the input pulsatile waveform shape on the mechanisms that drive the onset and development of transition using particle image velocimetry, three pulsatile waveforms, and six mean Reynolds numbers. The turbulent kinetic energy budget including dissipation rate, production, and pressure diffusion was computed. The results show that the waveform with a longer deceleration phase duration induced the earliest onset of transition, while the waveform with a longer acceleration period delayed the onset of transition. In accord with the findings of prior studies, for all test cases, turbulence was observed to be produced at the wall and either dissipated or redistributed into the core flow by pressure waves, depending on the mean Reynolds number. Turbulent production increased with increasing temporal velocity gradients until an asymptotic limit was reached. The turbulence dissipation rate was shown to be independent of mean Reynolds number, but a relationship between the temporal gradients of the input velocity waveform and the rate of turbulence dissipation was found. In general, these results demonstrated that the shape of the input pulsatile waveform directly affected the onset and development of transition.

  17. Semiochemicals released by pecan alleviate physiological suppression in overwintering larvae of Acrobasis nuxvorella (Lepidoptera: Pyralidae).

    Science.gov (United States)

    Vargas-Arispuro, I; Corella-Madueño, M A G; Harris, M K; Martínez-Téllez, M A; Gardea, A A; Fu-Castillo, A; Orozco-Avitia, A

    2013-10-01

    Acrobasis nuxvorella Neunzig (pecan nut casebearer) is a monophagous herbivore of Carya illinoinensis (Wang.) K. Koch (pecan); both are indigenous to North America, where Carya has evolved for ≈60 million years. We hypothesized that this close association may have resulted in a parallel evolution allowing casebearer to use pecan volatiles to synchronize seasonality. Casebearer overwinters in diapause as a first-instar larva in a hibernaculum attached to a dormant pecan bud. Larval emergence from this structure after diapause or postdiapause quiescence coincides with the onset of pecan bud growth in the spring, and this interaction was the subject of this study. Dormant pecan twigs with hibernacula-infested buds were exposed to a water control or pecan volatiles from 'Western Schley' cultivar, and monitored to observe larval response by using a microcalorimeter. Initial testing showed that metabolic heat produced by overwintering larvae remained low and unchanged when exposed to water vapor and significantly increased within a few hours after exposure to volatiles from new pecan foliage. This shows that these larvae in hibernacula are in a physiologically suppressed state of diapause or postdiapause quiescence, from which they detect and respond to these pecan volatiles. Further studies to quantify larval responses showed that 90 and 80% of the larvae became active and emerged from their hibernacula ≈6 d after exposure to Western Schley and 'Wichita' volatiles, respectively. Mixtures of 13 sesquiterpenes from those pecan volatiles were identified to induce physiological activity within larvae after hours of exposure, followed some days later by larval emergence from hibernacula. Host volatiles, to our knowledge, have not previously been reported to induce early instar larvae in hibernacula to rouse from a state of physiological arrest to resume normal growth and development. This also has potential for use in pest management.

  18. Increased plasma ghrelin suppresses insulin release in wethers fed with a high-protein diet.

    Science.gov (United States)

    Takahashi, T; Sato, K; Kato, S; Yonezawa, T; Kobayashi, Y; Ohtani, Y; Ohwada, S; Aso, H; Yamaguchi, T; Roh, S G; Katoh, K

    2014-06-01

    Ghrelin is a multifunctional peptide that promotes an increase of food intake and stimulates GH secretion. Ghrelin secretion is regulated by nutritional status and nutrients. Although a high-protein (HP) diet increases plasma ghrelin secretion in mammals, the mechanisms and the roles of the elevated ghrelin concentrations due to a HP diet have not been fully established. To clarify the roles of elevated acylated ghrelin upon intake of a HP diet, we investigated the regulation of ghrelin concentrations in plasma and tissues in wethers fed with either the HP diet or the control (CNT) diet for 14 days, and examined the action of the elevated plasma ghrelin by using a ghrelin-receptor antagonist. The HP diet gradually increased the plasma acylated-ghrelin concentrations, but the CNT diet did not. Although the GH concentrations did not vary significantly across the groups, an injection of ghrelin-receptor antagonist enhanced insulin levels in circulation in the HP diet group. In the fundus region of the stomach, the ghrelin levels did not differ between the HP and CNT diet groups, whereas ghrelin O-acyltransferase mRNA levels were higher in the group fed with HP diet than those of the CNT diet group were. These results indicate that the HP diet elevated the plasma ghrelin levels by increasing its synthesis; this elevation strongly suppresses the appearance of insulin in the circulation of wethers, but it is not involved in GH secretion. Overall, our findings indicate a role of endogenous ghrelin action in secretion of insulin, which acts as a regulator after the consumption of a HP diet. © 2014 Society for Endocrinology.

  19. Gonadotropin-releasing hormone 2 suppresses food intake in the zebrafish, Danio rerio

    Directory of Open Access Journals (Sweden)

    Ryo eNishiguchi

    2012-10-01

    Full Text Available Gonadotropin-releasing hormone (GnRH is an evolutionarily conserved neuropeptide with 10 amino acid residues, of which several structural variants exist. A molecular form known as GnRH2 ([His5 Trp7 Tyr8]GnRH, also known as chicken GnRH II is widely distributed in vertebrates except for rodents, and has recently been implicated in the regulation of feeding behavior in goldfish. However, the influence of GnRH2 on feeding behavior in other fish has not yet been studied. In the present study, therefore, we investigated the role of GnRH2 in the regulation of feeding behavior in a zebrafish model, and examined its involvement in food intake after intracerebroventricular (ICV administration. ICV injection of GnRH2 at 0.1 and 1 pmol/g body weight (BW induced a marked decrease of food consumption in a dose-dependent manner during 30 min after feeding. Cumulative food intake was significantly decreased by ICV injection of GnRH2 at 1 pmol/g BW during the 30-min post-treatment observation period. The anorexigenic action of GnRH2 was completely blocked by treatment with the GnRH type I receptor antagonist Antide at 50 pmol/g BW. We also examined the effect of feeding condition on the expression level of the GnRH2 transcript in the hypothalamus. Levels of GnRH2 mRNA obtained from fish that had been provided excess food for 7 days were higher than those in fish that had been fed normally. These results suggest that, in zebrafish, GnRH2 acts as an anorexigenic factor, as is the case in goldfish.

  20. Influence of hormonal control on LH pulsatility and secretion in women with classical congenital adrenal hyperplasia.

    Science.gov (United States)

    Bachelot, Anne; Chakhtoura, Zeina; Plu-Bureau, Geneviève; Coudert, Mathieu; Coussieu, Christiane; Badachi, Yasmina; Dulon, Jérome; Charbit, Beny; Touraine, Philippe

    2012-10-01

    Women with classical congenital adrenal hyperplasia (CAH) exhibit reduced fertility due to several factors including anovulation. This has been attributed to a disturbed gonadotropic axis as in polycystic ovary syndrome (PCOS), but there is no precise evaluation. Our aim was to evaluate the gonadotropic axis and LH pulsatility patterns and to determine factor(s) that could account for the potential abnormality of LH pulsatility. Case/control study. Sixteen CAH women (11 with the salt-wasting form and five with the simple virilizing form), aged from 18 to 40 years, and 16 age-matched women, with regular menstrual cycles (28 ± 3 days), were included. LH pulse patterns over 6 h were determined in patients and controls. No differences were observed between patients and controls in terms of mean LH levels, LH pulse amplitude, or LH frequency. In CAH patients, LH pulsatility patterns were heterogeneous, leading us to perform a clustering analysis of LH data, resulting in a two-cluster partition. Patients in cluster 1 had similar LH pulsatility patterns to the controls. Patients in cluster 2 had: lower LH pulse amplitude and frequency and presented menstrual cycle disturbances more frequently; higher 17-OH progesterone, testosterone, progesterone, and androstenedione levels; and lower FSH levels. LH pulsatility may be normal in CAH women well controlled by hormonal treatment. Undertreatment is responsible for hypogonadotropic hypogonadism, with low LH pulse levels and frequency, but not PCOS. Suppression of progesterone and androgen concentrations during the follicular phase of the menstrual cycle should be a major objective in these patients.

  1. Electroresponsive polymer-carbon nanotube hydrogel hybrids for pulsatile drug delivery in vivo.

    Science.gov (United States)

    Servant, Ania; Methven, Laura; Williams, Rhodri P; Kostarelos, Kostas

    2013-06-01

    Drug release triggered by an external non-invasive stimulus is of great interest for the development of new drug delivery systems. The preparation of an electroresponsive multiwalled carbon nanotube/poly(methylacrylic acid) (MWNT/PMAA)-based hybrid material is reported. The hydrogel hybrids achieve a controlled drug release upon the ON/OFF application of an electric field, giving rise to in vitro and in vivo pulsatile release profiles. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. The Use of a Combined Regimen of GnRH Agonist Plus a Low-Dose Oral Contraceptive Improves the Spontaneous Pulsatile LH Secretory Characteristics in Patients with Polycycstic Ovary Disease After Discontinuation of Treatment

    OpenAIRE

    Genazzani, Alessandro D.; Battaglia, Cesare; Gamba, Ombretta; Petraglia, Felice; Malavasi, Barbara; Genazzani, Andrea R.

    2000-01-01

    Purpose: The fertility rate in women with polycystic ovarydisease (PCOD) is influenced by the type of treatmentreceived. The present study evaluated the possiblecorrelation between treatment and pulsatile release ofgonadotropins.

  3. ATP Release from Chemotherapy-Treated Dying Leukemia Cells Elicits an Immune Suppressive Effect by Increasing Regulatory T Cells and Tolerogenic Dendritic Cells.

    Science.gov (United States)

    Lecciso, Mariangela; Ocadlikova, Darina; Sangaletti, Sabina; Trabanelli, Sara; De Marchi, Elena; Orioli, Elisa; Pegoraro, Anna; Portararo, Paola; Jandus, Camilla; Bontadini, Andrea; Redavid, Annarita; Salvestrini, Valentina; Romero, Pedro; Colombo, Mario P; Di Virgilio, Francesco; Cavo, Michele; Adinolfi, Elena; Curti, Antonio

    2017-01-01

    Chemotherapy-induced immunogenic cell death can favor dendritic cell (DC) cross-priming of tumor-associated antigens for T cell activation thanks to the release of damage-associated molecular patterns, including ATP. Here, we tested the hypothesis that in acute myeloid leukemia (AML), ATP release, along with its well-known immune stimulatory effect, may also contribute to the generation of an immune suppressive microenvironment. In a cohort of AML patients, undergoing combined daunorubicin and cytarabine chemotherapy, a population of T regulatory cells (Tregs) with suppressive phenotype, expressing the immune checkpoint programmed cell death protein 1 (PD-1), was significantly increased. Moving from these results, initial in vitro data showed that daunorubicin was more effective than cytarabine in modulating DC function toward Tregs induction and such difference was correlated with the higher capacity of daunorubicin to induce ATP release from treated AML cells. DCs cultured with daunorubicin-treated AML cells upregulated indoleamine 2,3-dioxygenase 1 (IDO1), which induced anti-leukemia Tregs. These data were confirmed in vivo as daunorubicin-treated mice show an increase in extracellular ATP levels with increased number of Tregs, expressing PD-1 and IDO1 + CD39 + DCs. Notably, daunorubicin failed to induce Tregs and tolerogenic DCs in mice lacking the ATP receptor P2X7. Our data indicate that ATP release from chemotherapy-treated dying cells contributes to create an immune suppressive microenvironment in AML.

  4. ATP Release from Chemotherapy-Treated Dying Leukemia Cells Elicits an Immune Suppressive Effect by Increasing Regulatory T Cells and Tolerogenic Dendritic Cells

    Directory of Open Access Journals (Sweden)

    Mariangela Lecciso

    2017-12-01

    Full Text Available Chemotherapy-induced immunogenic cell death can favor dendritic cell (DC cross-priming of tumor-associated antigens for T cell activation thanks to the release of damage-associated molecular patterns, including ATP. Here, we tested the hypothesis that in acute myeloid leukemia (AML, ATP release, along with its well-known immune stimulatory effect, may also contribute to the generation of an immune suppressive microenvironment. In a cohort of AML patients, undergoing combined daunorubicin and cytarabine chemotherapy, a population of T regulatory cells (Tregs with suppressive phenotype, expressing the immune checkpoint programmed cell death protein 1 (PD-1, was significantly increased. Moving from these results, initial in vitro data showed that daunorubicin was more effective than cytarabine in modulating DC function toward Tregs induction and such difference was correlated with the higher capacity of daunorubicin to induce ATP release from treated AML cells. DCs cultured with daunorubicin-treated AML cells upregulated indoleamine 2,3-dioxygenase 1 (IDO1, which induced anti-leukemia Tregs. These data were confirmed in vivo as daunorubicin-treated mice show an increase in extracellular ATP levels with increased number of Tregs, expressing PD-1 and IDO1+CD39+ DCs. Notably, daunorubicin failed to induce Tregs and tolerogenic DCs in mice lacking the ATP receptor P2X7. Our data indicate that ATP release from chemotherapy-treated dying cells contributes to create an immune suppressive microenvironment in AML.

  5. Hydrogen sulfide-releasing naproxen suppresses colon cancer cell growth and inhibits NF-κB signaling

    Directory of Open Access Journals (Sweden)

    Kodela R

    2015-08-01

    Full Text Available Ravinder Kodela,1 Niharika Nath,2 Mitali Chattopadhyay,1 Diandra E Nesbitt,1 Carlos A Velázquez-Martínez,3 Khosrow Kashfi11Department of Physiology, Pharmacology and Neuroscience, Sophie Davis School of Biomedical Education, City University of New York Medical School, 2Department of Life Sciences, New York Institute of Technology, New York, NY, USA; 3Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, Edmonton, AB, Canada Abstract: Colorectal cancer (CRC is the second leading cause of death due to cancer and the third most common cancer in men and women in the USA. Nuclear factor kappa B (NF-κB is known to be activated in CRC and is strongly implicated in its development and progression. Therefore, activated NF-κB constitutes a bona fide target for drug development in this type of malignancy. Many epidemiological and interventional studies have established nonsteroidal anti-inflammatory drugs (NSAIDs as a viable chemopreventive strategy against CRC. Our previous studies have shown that several novel hydrogen sulfide-releasing NSAIDs are promising anticancer agents and are safer derivatives of NSAIDs. In this study, we examined the growth inhibitory effect of a novel H2S-releasing naproxen (HS-NAP, which has a repertoire as a cardiovascular-safe NSAID, for its effects on cell proliferation, cell cycle phase transitions, and apoptosis using HT-29 human colon cancer cells. We also investigated its effect as a chemopreventive agent in a xenograft mouse model. HS-NAP suppressed the growth of HT-29 cells by induction of G0/G1 arrest and apoptosis and downregulated NF-κB. Tumor xenografts in mice were significantly reduced in volume. The decrease in tumor mass was associated with a reduction of cell proliferation, induction of apoptosis, and decreases in NF-κB levels in vivo. Therefore, HS-NAP demonstrates strong anticancer potential in CRC. Keywords: nonsteroidal anti-inflammatory drugs, cell cycle, apoptosis, xenograft, NF

  6. Nanoscaffold matrices for size-controlled, pulsatile transdermal testosterone delivery: nanosize effects on the time dimension

    International Nuclear Information System (INIS)

    Malik, Ritu; Misra, Amit; Tondwal, Shailesh; Venkatesh, K S

    2008-01-01

    Pulsatile transdermal testosterone (T) has applications in hormone supplementation and male contraception. Pulsatile T delivery was achieved by assembling crystalline and nanoparticulate T in nucleation-inhibiting polymer matrices of controlled porosity. Different interference patterns observed from various polymeric films containing T were due to the various particle sizes of T present in the polymer matrices. Scanning electron microscopy was used to determine the size and shape of T crystals. Skin-adherent films containing T nanoparticles of any size between 10-500 nm could be prepared using pharmaceutically acceptable vinylic polymers. Drug release and skin permeation profiles were studied. The dissolution-diffusion behavior of nanoparticles differed from crystalline and molecular states. Nanosize may thus be used to engineer chronopharmacologically relevant drug delivery.

  7. Nanoscaffold matrices for size-controlled, pulsatile transdermal testosterone delivery: nanosize effects on the time dimension

    Science.gov (United States)

    Malik, Ritu; Tondwal, Shailesh; Venkatesh, K. S.; Misra, Amit

    2008-10-01

    Pulsatile transdermal testosterone (T) has applications in hormone supplementation and male contraception. Pulsatile T delivery was achieved by assembling crystalline and nanoparticulate T in nucleation-inhibiting polymer matrices of controlled porosity. Different interference patterns observed from various polymeric films containing T were due to the various particle sizes of T present in the polymer matrices. Scanning electron microscopy was used to determine the size and shape of T crystals. Skin-adherent films containing T nanoparticles of any size between 10-500 nm could be prepared using pharmaceutically acceptable vinylic polymers. Drug release and skin permeation profiles were studied. The dissolution-diffusion behavior of nanoparticles differed from crystalline and molecular states. Nanosize may thus be used to engineer chronopharmacologically relevant drug delivery.

  8. Chronotherapeutically Modulated Pulsatile System of Valsartan Nanocrystals-an In Vitro and In Vivo Evaluation.

    Science.gov (United States)

    Biswas, Nikhil; Kuotsu, Ketousetuo

    2017-02-01

    The objective was to improve the dissolution of valsartan by developing valsartan nanocrystals and design a pulsed release system for the chronotherapy of hypertension. Valsartan nanocrystals were prepared by sonication-anti-solvent precipitation method and lyophilized to obtain dry powder. Nanocrystals were directly compressed to minitablets and coated to achieve pulsatile valsartan release. Pharmacokinetic profiles of optimized and commercial formulations were compared in rabbit model. The mean particle size and PDI of the optimized nanocrystal batch V4 was reported as 211 nm and 0.117, respectively. DSC and PXRD analysis confirmed the crystalline nature of valsartan in nanocrystals. The dissolution extent of valsartan was markedly enhanced with both nanocrystals and minitablets as compared to pure valsartan irrespective of pH of the medium. Core minitablet V4F containing 5% w/w polyplasdone XL showed quickest release of valsartan, over 90% within 15 min. Coated formulation CV4F showed two spikes in release profile after successive lag times of 235 and 390 min. The pharmacokinetic study revealed that the bioavailability of optimized formulation (72.90%) was significantly higher than the commercial Diovan tablet (30.18%). The accelerated stability studies showed no significant changes in physicochemical properties, release behavior, and bioavialability of CV4F formulation. The formulation was successfully designed to achieve enhanced bioavailability and dual pulsatile release. Bedtime dosing will more efficiently control the circadian spikes of hypertension in the morning.

  9. Pulsatile luteinizing hormone secretion in patients with Addison's disease. Impact of glucocorticoid substitution

    DEFF Research Database (Denmark)

    Hangaard, J; Andersen, M; Grodum, E

    1998-01-01

    The physiological and pathophysiological role of cortisol in pulsatile LH release was investigated in 14 patients (5 men, 6 premenopausal women, and 3 postmenopausal women) with Addison's disease. The explicit effect of cortisol in relation to the effect of corticotropin-releasing factor (CRF......), ACTH, and opioids was ensured by hypo-, normo-, and hypercortisolism. Hypocortisolism was obtained by 24-h discontinuation of hydrocortisone (HC) followed by 23-h saline infusion. Eucortisolism was secured by infusion of HC (0.5 mg/kg) over 23 h. Stress-appropriate hypercortisolism was obtained...

  10. Pulsatile flow in ventricular catheters for hydrocephalus

    Science.gov (United States)

    Giménez, Á.; Galarza, M.; Thomale, U.; Schuhmann, M. U.; Valero, J.; Amigó, J. M.

    2017-05-01

    The obstruction of ventricular catheters (VCs) is a major problem in the standard treatment of hydrocephalus, the flow pattern of the cerebrospinal fluid (CSF) being one important factor thereof. As a first approach to this problem, some of the authors studied previously the CSF flow through VCs under time-independent boundary conditions by means of computational fluid dynamics in three-dimensional models. This allowed us to derive a few basic principles which led to designs with improved flow patterns regarding the obstruction problem. However, the flow of the CSF has actually a pulsatile nature because of the heart beating and blood flow. To address this fact, here we extend our previous computational study to models with oscillatory boundary conditions. The new results will be compared with the results for constant flows and discussed. It turns out that the corrections due to the pulsatility of the CSF are quantitatively small, which reinforces our previous findings and conclusions. This article is part of the themed issue `Mathematical methods in medicine: neuroscience, cardiology and pathology'.

  11. Positron emission particle tracking in pulsatile flow

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Nitant; Ruggles, Arthur [University of Tennessee-Knoxville, Department of Nuclear Engineering, Knoxville, TN (United States); Wiggins, Cody [University of Tennessee-Knoxville, Department of Physics and Astronomy, Knoxville, TN (United States)

    2017-05-15

    Positron emission particle tracking (PEPT) is increasingly used to understand the flow characteristics in complex systems. This research utilizes PEPT to measure pulsatile flow of frequency 2.1 Hz in an elastic Masterkleer PVC tube of 19 mm inner diameter and 3.2 mm wall thickness. Anion exchange resin beads are labeled with {sup 18}F and delivered to a pump driven flow loop with motorized ball valve used to develop the pulsatile flow. Data are collected in the tube with circular cross section, and measurements are also collected with a section of the tube pinched. Nominal flow velocities are near 1 m/s and Reynolds numbers near 20,000. Many thousand PEPT particle traces are collected and synchronized with the flow pulsation. These Lagrangian data are presented as a series of 20 still frames depicting the 3-D velocity field present during each phase of the flow pulsation. Pressure data are also collected to resolve the pressure wave front moving through the open elastic tube at velocity 15.2 m/s. (orig.)

  12. Pulmonary O2 transfer during pulsatile and non-pulsatile perfusion.

    Science.gov (United States)

    Hauge, A; Nicolaysen, G

    1980-07-01

    The importance of the perfusion pattern for the oxygen transfer has been examined in isolated rabbit lungs perfused with plasma at constant volume inflow. The lungs were ventilated with constant tidal volume and constant end-expiratory pressure. Following a standardized rise in FIO2 the rate of rise in pulmonary venous PO2 (delta PO2/delta t) was measured during alternately pulsatile and non-pulsatile perfusion in normal lungs and in lungs made edematous by elevation of left atrial pressure. In normal lungs there was no difference in delta PO2/delta t when the two modes of perfusion were compared. In edematous lungs delta PO/delta t was statistically higher during pulsatile perfusion, indicating a beneficial effect of flow- and pressure pulsations, e.g. a better distribution of V/Q ratios throughout the lungs. In a separate series of expts. the advancement of a high O2 front through the airways was measured, and the two perfusion patterns compared. Since no difference was found, we suggest that the phenomenon of "cardiogenic gas mixing" in the airways in vivo is a result of a direct action of the heart on the lungs rather than arterial pulsations.

  13. Pulsatile spiral blood flow through arterial stenosis.

    Science.gov (United States)

    Linge, Fabian; Hye, Md Abdul; Paul, Manosh C

    2014-11-01

    Pulsatile spiral blood flow in a modelled three-dimensional arterial stenosis, with a 75% cross-sectional area reduction, is investigated by using numerical fluid dynamics. Two-equation k-ω model is used for the simulation of the transitional flow with Reynolds numbers 500 and 1000. It is found that the spiral component increases the static pressure in the vessel during the deceleration phase of the flow pulse. In addition, the spiral component reduces the turbulence intensity and wall shear stress found in the post-stenosis region of the vessel in the early stages of the flow pulse. Hence, the findings agree with the results of Stonebridge et al. (2004). In addition, the results of the effects of a spiral component on time-varying flow are presented and discussed along with the relevant pathological issues.

  14. Anti-inflammatory effect with high intensity focused ultrasound-mediated pulsatile delivery of diclofenac.

    Science.gov (United States)

    Wang, Chih-Yu; Yang, Chih-Hui; Lin, Yung-Sheng; Chen, Chih-Hsin; Huang, Keng-Shiang

    2012-02-01

    A pulsatile ultrasound controlled drug release platform with diclofenac-loaded alginate microcapsules (fabricated with a home-made electrostatic device, 75% embedded rate) was established to evaluate anti-inflammation efficiency. Better anti-inflammation efficiency was found using the ultrasound system and the drug delivery can be adjusted based on the programmed ultrasound cycle. The results of the in vitro study show that an approx. 30% higher drug release rate was obtained by using continuous ultrasound irradiation (9-Watt, 180 min), and an approx. 16% higher drug release rate was obtained by using pulsatile ultrasound irradiation (9-Watt, 60 min) compared to without ultrasound activation. For the in vivo study, the anti-inflammatory test with carrageenan-induced rat's paw edema shows that diclofenac-loaded microcapsules followed by ultrasound irradiation (9-Watt, 60 min) contributed to an 81% inhibition rate, which was significantly higher than diclofenac only (approx. 60% higher). In addition, because of their heat conducting properties, gold nanoparticles encapsulated in the diclofenac-loaded microcapsules resulted in better drug release efficiency, but tended to depress the anti-inflammation effect. Copyright © 2011 Elsevier Ltd. All rights reserved.

  15. Demonstration of uneven distribution of intracranial pulsatility in hydrocephalus patients.

    Science.gov (United States)

    Eide, Per K

    2008-11-01

    Data from intracranial pressure (ICP) recordings in patients with hydrocephalus were reviewed to determine whether intracranial pulsatility within the cerebrospinal fluid (CSF) of cerebral ventricles (ICP(LV)) may differ from that within the brain parenchyma (ICP(PAR)), and whether pulsatility may differ between noncommunicating ventricles. The authors retrieved data from recordings previously obtained in 7 patients with hydrocephalus (noncommunicating in 4 and communicating in 3) and shunt failure who received both an external ventricular drainage (EVD) and an ICP sensor as part of surveillance during intensive care. Simultaneous ICP(LV) and ICP(PAR) signals were available in 6 cases, and simultaneous signals from the lateral and fourth ventricles (ICP(LV) and ICP4V, respectively) were recorded in 1 case. The recordings with both signals were parsed into 6-second time windows. Pulsatility was characterized by the wave amplitude and rise time coefficient, and differences in pulsatility between the ICP(LV) and ICP(PAR) signals (6 cases) or ICP(LV) and ICP4V signals (1 case) were determined. There was uneven distribution of intracranial pulsatility in all 7 patients, shown as significantly elevated pulsatility (that is, higher wave amplitudes and rise time coefficients) within the ventricles (ICP(LV)) than within brain parenchyma (ICP(PAR)) in 6 patients, and significantly higher pulsatility in the fourth (ICP4V) than in the lateral (ICP(LV)) ventricles in 1 patient. Differences > or = 1 mm Hg in ICP wave amplitude were found in 0.5-100% (median 9.4%) of observations in the 7 patients (total number of 6-second time windows, 68,242). The present observations demonstrate uneven distribution of intracranial pulsatility in patients with hydrocephalus, higher pulse pressure amplitudes within the ventricular CSF (ICP(LV)) than within the brain parenchyma (ICP(PAR)). This may be one mechanism behind ventricular enlargement in hydrocephalus.

  16. C–C Chemokines Released by Lipopolysaccharide (LPS)-stimulated Human Macrophages Suppress HIV-1 Infection in Both Macrophages and T Cells

    Science.gov (United States)

    Verani, Alessia; Scarlatti, Gabriella; Comar, Manola; Tresoldi, Eleonora; Polo, Simona; Giacca, Mauro; Lusso, Paolo; Siccardi, Antonio G.; Vercelli, Donata

    1997-01-01

    Human immunodeficiency virus-1 (HIV-1) expression in monocyte-derived macrophages (MDM) infected in vitro is known to be inhibited by lipopolysaccharide (LPS). However, the mechanisms are incompletely understood. We show here that HIV-1 suppression is mediated by soluble factors released by MDM stimulated with physiologically significant concentrations of LPS. LPS-conditioned supernatants from MDM inhibited HIV-1 replication in both MDM and T cells. Depletion of C–C chemokines (RANTES, MIP-1α, and MIP-1β) neutralized the ability of LPS-conditioned supernatants to inhibit HIV-1 replication in MDM. A combination of recombinant C–C chemokines blocked HIV-1 infection as effectively as LPS. Here, we report an inhibitory effect of C–C chemokines on HIV replication in primary macrophages. Our results raise the possibility that monocytes may play a dual role in HIV infection: while representing a reservoir for the virus, they may contribute to the containment of the infection by releasing factors that suppress HIV replication not only in monocytes but also in T lymphocytes. PMID:9120386

  17. Suppression of MMP activity in bovine cartilage explants cultures has little if any effect on the release of aggrecanase-derived aggrecan fragments

    Directory of Open Access Journals (Sweden)

    Sondergaard Bodil-Cecilie

    2009-12-01

    Full Text Available Abstract Background Progressive loss of articular cartilage is a central hallmark in many joint disease, however, the relative importance of individual proteolytic pathways leading to cartilage erosion is at present unknown. We therefore investigated the time-dependant release ex vivo of MMP- and aggrecanase-derived fragments of aggrecan and type II collagen into the supernatant of bovine cartilage explants cultures using neo-epitope specific immunoassays, and to associate the release of these fragments with the activity of proteolytic enzymes using inhibitors. Findings Bovine cartilage explants were cultured in the presence or absence of the catabolic cytokines oncostatin M (OSM and tumor necrosis factor alpha (TNFα. In parallel, explants were co-cultured with protease inhibitors such as GM6001, TIMP1, TIMP2 and TIMP3. Fragments released into the supernatant were determined using a range of neo-epitope specific immunoassays; (1 sandwich 342FFGVG-G2 ELISA, (2 competition NITEGE373ELISA (3 sandwich G1-NITEGE373 ELISA (4 competition 374ARGSV ELISA, and (5 sandwich 374ARGSV-G2 ELISA all detecting aggrecan fragments, and (6 sandwich CTX-II ELISA, detecting C-telopeptides of type II collagen. We found that (1 aggrecanase-derived aggrecan fragments are released in the early (day 2-7 and mid phase (day 9-14 into the supernatant from bovine explants cultures stimulated with catabolic cytokines, (2 the release of NITEGE373 neo-epitopes are delayed compared to the corresponding 374ARGSV fragments, (3 the MMP inhibitor GM6001 did not reduce the release of aggrecanase-derived fragment, but induced a further delay in the release of these fragments, and finally (4 the MMP-derived aggrecan and type II collagen fragments were released in the late phase (day 16-21 only. Conclusion Our data support the model, that aggrecanases and MMPs act independently in the processing of the aggrecan molecules, and furthermore that suppression of MMP-activity had little if

  18. Measuring pulsatile forces on the human cranium.

    Science.gov (United States)

    Goldberg, Cory S; Antonyshyn, Oleh; Midha, Rajiv; Fialkov, Jeffrey A

    2005-01-01

    The cyclic stresses in the cranium caused by pulsation of the brain play an important role in the design of materials for cranioplasty, as well as craniofacial development. However, these stresses have never been quantified. In this study, the force in the epidural space against the cranium was measured intraoperatively in 10 patients using a miniature force probe. Heart and ventilatory rates computed from the force tracing correlated closely with the corresponding measured values in the patients, confirming that the forces measured were indeed a result of brain pulsation. The mean outward systolic normal and tangential stresses were 54.2 kilo-Pascals (kPa) and 345.4 kPa, respectively. The systolic shear stress was 199.8 kPa. Through mechanotransduction, these stresses play a role in cranial development. The calculated yield stress of a cranioplasty repair was 0.4 MPa, which is within one order of magnitude of the known strength of common calcium-phosphate cements. This indicates a possible relation of these pulsatile forces and occult failure of calcium-phosphate cement cranioplasties through material fatigue.

  19. Arduino control of a pulsatile flow rig.

    Science.gov (United States)

    Drost, S; de Kruif, B J; Newport, D

    2018-01-01

    This note describes the design and testing of a programmable pulsatile flow pump using an Arduino micro-controller. The goal of this work is to build a compact and affordable system that can relatively easily be programmed to generate physiological waveforms. The system described here was designed to be used in an in-vitro set-up for vascular access hemodynamics research, and hence incorporates a gear pump that delivers a mean flow of 900 ml/min in a test flow loop, and a peak flow of 1106 ml/min. After a number of simple identification experiments to assess the dynamic behaviour of the system, a feed-forward control routine was implemented. The resulting system was shown to be able to produce the targeted representative waveform with less than 3.6% error. Finally, we outline how to further increase the accuracy of the system, and how to adapt it to specific user needs. Copyright © 2017 IPEM. Published by Elsevier Ltd. All rights reserved.

  20. Large indoor cage study of the suppression of stable Aedes aegypti populations by the release of thiotepa-sterilised males

    Directory of Open Access Journals (Sweden)

    René Gato

    2014-06-01

    Full Text Available The sterile insect technique (SIT is a promising pest control method in terms of efficacy and environmental compatibility. In this study, we determined the efficacy of thiotepa-sterilised males in reducing the target Aedes aegypti populations. Treated male pupae were released weekly into large laboratory cages at a constant ratio of either 5:1 or 2:1 sterile-to-fertile males. A two-to-one release ratio reduced the hatch rate of eggs laid in the cage by approximately a third and reduced the adult catch rate by approximately a quarter, but a 5:1 release drove the population to elimination after 15 weeks of release. These results indicate that thiotepa exposure is an effective means of sterilising Ae. aegypti and males thus treated are able to reduce the reproductive capacity of a stable population under laboratory conditions. Further testing of the method in semi-field enclosures is required to evaluate the mating competitiveness of sterile males when exposed to natural environmental conditions. If proven effective, SIT using thiotepa-sterilised males may be incorporated into an integrated programme of vector control to combat dengue in Cuba.

  1. Suppress orthotopic colon cancer and its metastasis through exact targeting and highly selective drug release by a smart nanomicelle.

    Science.gov (United States)

    Zhu, Chunqi; Zhang, Hanbo; Li, Wei; Luo, Lihua; Guo, Xiaomeng; Wang, Zuhua; Kong, Fenfen; Li, Qingpo; Yang, Jie; Du, Yongzhong; You, Jian

    2018-04-01

    The treatment of metastatic cancer is a huge challenge at the moment. Highly precise targeting delivery and drug release in tumor have always been our pursuit in cancer therapy, especially to advance cancer with metastasis, for increasing the efficacy and biosafety. We established a smart nanosized micelle, formed by tocopherol succinate (TOS) conjugated hyaluronic acid (HA) using a disulfide bond linker. The micelle (HA-SS-TOS, HSST) can highly specifically bind with CD44 receptor over-expressed tumor, and response selectively to high GSH level in the cells, inducing disulfide bond breakage and the release of the payload (paclitaxel, PTX). To predict the antitumor efficacy of the micelles more clinically, we established an orthotopic colon cancer model with high metastasis rate, which could be visualized by the luciferase bioluminescence. Our data confirmed CD44 high expression in the colon cancer cells. Highly matching between the micellar fluorescence and bioluminescence of cancer cells in intestines demonstrated an exact recognition of our micelles to orthotopic colon tumor and its metastatic cells, attributing to the mediation of CD44 receptors. Furthermore, the fluorescence of the released Nile Red from the micelles was found only in the tumor and its metastatic cells, and almost completely overlapped with the bioluminescence of the cancer cells, indicating a highly selective drug release. Our micelles presented an excellent therapeutic effect against metastatic colon cancer, and induced significantly prolonged survival time for the mice, which might become a promising nanomedicine platform for the future clinical application against advanced cancers with high CD44 receptor expression. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. Inhibition of Mitochondrial Cytochrome c Release and Suppression of Caspases by Gamma-Tocotrienol Prevent Apoptosis and Delay Aging in Stress-Induced Premature Senescence of Skin Fibroblasts

    Directory of Open Access Journals (Sweden)

    Suzana Makpol

    2012-01-01

    Full Text Available In this study, we determined the molecular mechanism of γ-tocotrienol (GTT in preventing cellular aging by focusing on its anti-apoptotic effect in stress-induced premature senescence (SIPS model of human diploid fibroblasts (HDFs. Results obtained showed that SIPS exhibited senescent-phenotypic characteristic, increased expression of senescence-associated β-galactosidase (SA β-gal and promoted G0/G1 cell cycle arrest accompanied by shortening of telomere length with decreased telomerase activity. Both SIPS and senescent HDFs shared similar apoptotic changes such as increased Annexin V-FITC positive cells, increased cytochrome c release and increased activation of caspase-9 and caspase-3 (P<0.05. GTT treatment resulted in a significant reduction of Annexin V-FITC positive cells, inhibited cytochrome c release and decreased activation of caspase-9 and caspase-3 (P<0.05. Gene expression analysis showed that GTT treatment down regulated BAX mRNA, up-regulated BCL2A1 mRNA and decreased the ratio of Bax/Bcl-2 protein expression (P<0.05 in SIPS. These findings suggested that GTT inhibits apoptosis by modulating the upstream apoptosis cascade, causing the inhibition of cytochrome c release from the mitochondria with concomitant suppression of caspase-9 and caspase-3 activation. In conclusion, GTT delays cellular senescence of human diploid fibroblasts through the inhibition of intrinsic mitochondria-mediated pathway which involved the regulation of pro- and anti-apoptotic genes and proteins.

  3. Effects of continuous and pulsatile PTH treatments on rat bone marrow stromal cells

    International Nuclear Information System (INIS)

    Yang Chiming; Frei, Hanspeter; Burt, Helen M.; Rossi, Fabio

    2009-01-01

    Bone marrow stromal cells (MSCs) differentiation and proliferation are controlled by numerous growth factors and hormones. Continuous parathyroid hormone (PTH) treatment has been shown to decrease osteoblast differentiation, whereas pulsatile PTH increases osteoblast differentiation. However, the effects of PTH treatments on MSCs have not been investigated. This study showed continuous PTH treatment in the presence of dexamethasone (DEX) promoted osteogenic differentiation of rat MSCs in vitro, as demonstrated by increased alkaline phosphatase (ALP) activity, number of ALP expressing cells, and up-regulation of PTH receptor-1, ALP, and osteocalcin mRNA expressions. In contrast, pulsatile PTH treatment was found to suppress osteogenesis of rat MSCs, possibly by promoting the maintenance of undifferentiated cells. Additionally, the observed effects of PTH were strongly dependent on the presence of DEX. MSC proliferation however was not influenced by PTH independent of treatment regimen and presence or absence of DEX. Furthermore, our work raised the possibility that PTH treatment may modulate stem/progenitor cell activity within MSC cultures.

  4. Impaired crosstalk between pulsatile insulin and glucagon secretion in prediabetic individuals

    DEFF Research Database (Denmark)

    Rohrer, Stefan; Menge, Björn A; Grüber, Lena

    2012-01-01

    Postprandial hyperglucagonemia is frequently found in patients with diabetes. Recently, a loss of the inverse relationship between pulsatile insulin and glucagon secretion has been reported in patients with type 2 diabetes. The crosstalk between pulsatile islet hormone secretion in prediabetic...

  5. Suppression of basophil histamine release and other IgE-dependent responses in childhood Schistosoma mansoni/hookworm coinfection

    DEFF Research Database (Denmark)

    Pinot de Moira, Angela; Fitzsimmons, Colin M; Jones, Frances M

    2014-01-01

    (HR), plus helminth- and HDM-specific IgE and IgG4 responses were measured pre- and post-treatment. RESULTS: Nonspecific- and helminth-specific-HR, and associations between helminth-specific IgE and helminth-specific HR increased post-treatment. Hookworm infection appeared to modify the relationship...... between circulating levels of HDM-IgE and HR: a significant positive association was observed among children without detectable hookworm infection, but no association was observed among infected children. In addition, hookworm infection was associated with a significantly reduced risk of wheeze, and IgG4...... in Ugandan schoolchildren coinfected with Schistosoma mansoni and hookworm. METHODS: Skin prick test (SPT) sensitivity to house dust mite allergen (HDM) and current wheeze were assessed pre-anthelmintic treatment. Nonspecific (anti-IgE), helminth-specific, and HDM-allergen-specific basophil histamine release...

  6. Glucose uptake and pulsatile insulin infusion: euglycaemic clamp and [3-3H]glucose studies in healthy subjects

    International Nuclear Information System (INIS)

    Schmitz, O.; Arnfred, J.; Hother Nielsen, O.; Beck-Nielsen, H.; Oerskov, H.

    1986-01-01

    To test the hypothesis that insulin has a greater effect on glucose metabolism when given as pulsatile than as continuous infusion, a 354-min euglycaemic clamp study was carried out in 8 healthy subjects. At random order soluble insulin was given intravenously either at a constant rate of 0.45mU/kg · min or in identical amounts in pulses of 1 1 / 2 to 2 1 / 4 min followed by intervals of 10 1 / 2 to 9 3 / 4 min. Average serum insulin levels were similar during the two infusion protocols, but pulsatile administration induced oscillations ranging between 15 and 62 μU/ml. Glucose uptake expressed as metabolic clearance rate (MCR) for glucose was significantly increased during pulsatile insulin delivery as compared with continuous administration (270-294 min: 8.7±0.7 vs 6.8±0.9 ml/kg · min, P 3 H]glucose infusion technique was suppressed to insignificant values. Finally, the effect of insulin on endogenous insulin secretion and lipolysis as assessed by changes in serum C-peptide and serum FFA was uninfluenced by the infusion mode. In conclusion, insulin infusion resulting in physiological serum insulin levels enhances glucose uptake in peripheral tissues in healthy subjects to a higher degree when given in a pulsed pattern mimicking that of the normal endocrine pancreas than when given as a continuous infusion. (author)

  7. Heme Oxygenase-1 Induction by Carbon Monoxide Releasing Molecule-3 Suppresses Interleukin-1β-Mediated Neuroinflammation

    Directory of Open Access Journals (Sweden)

    Chih-Chung Lin

    2017-11-01

    Full Text Available Neurodegenerative disorders and brain damage are initiated by excessive production of reactive oxygen species (ROS, which leads to tissue injury, cellular death and inflammation. In cellular anti-oxidant systems, heme oxygenase-1 (HO-1 is an oxidative-sensor protein induced by ROS generation or carbon monoxide (CO release. CO releasing molecules (CORMs, including CORM-3, exert anti-oxidant and anti-inflammatory effects. However, the molecular mechanisms of CORM-3-induced HO-1 expression and protection against interleukin (IL-1β-induced inflammatory responses have not been fully elucidated in rat brain astrocytes (RBA-1. To study the regulation of CORM-3-induced HO-1 expression, signaling pathways, promoter activity, mRNA and protein expression were assessed following treatment with pharmacological inhibitors and gene-specific siRNA knockdown. We found that CORM-3 mediated HO-1 induction via transcritional and translational processes. Furthermore, CORM-3-induced HO-1 expression was mediated by phosphorylation of several protein kinases, such as c-Src, Pyk2, protein kinase Cα (PKCα and p42/p44 mitogen-activated protein kinase (MAPK, which were inhibited by respective pharmacological inhibitors or by gene-specific knockdown with siRNA transfections. Next, we found that CORM-3 sequentially activated the c-Src/Pyk2/PKCα/p42/p44 MAPK pathway, thereby up-regulating mRNA for the activator protein (AP-1 components c-Jun and c-Fos; these effects were attenuated by an AP-1 inhibitor (Tanshinone IIA; TSIIA and other relevant inhibitors. Moreover, CORM-3-induced upregulation of HO-1 attenuated the IL-1β-induced cell migration and matrix metallopeptidase-9 mRNA expression in RBA-1 cells. These effects were reversed by an matrix metalloproteinase (MMP2/9 inhibitor or by transfection with HO-1 siRNA.

  8. Loss of inverse relationship between pulsatile insulin and glucagon secretion in patients with type 2 diabetes

    DEFF Research Database (Denmark)

    Menge, Björn A; Grüber, Lena; Jørgensen, Signe M

    2011-01-01

    In patients with type 2 diabetes, glucagon levels are often increased. Furthermore, pulsatile secretion of insulin is disturbed in such patients. Whether pulsatile glucagon secretion is altered in type 2 diabetes is not known.......In patients with type 2 diabetes, glucagon levels are often increased. Furthermore, pulsatile secretion of insulin is disturbed in such patients. Whether pulsatile glucagon secretion is altered in type 2 diabetes is not known....

  9. Pulsatile operation of a continuous-flow right ventricular assist device (RVAD) to improve vascular pulsatility.

    Science.gov (United States)

    Ng, Boon C; Kleinheyer, Matthias; Smith, Peter A; Timms, Daniel; Cohn, William E; Lim, Einly

    2018-01-01

    Despite the widespread acceptance of rotary blood pump (RBP) in clinical use over the past decades, the diminished flow pulsatility generated by a fixed speed RBP has been regarded as a potential factor that may lead to adverse events such as vasculature stiffening and hemorrhagic strokes. In this study, we investigate the feasibility of generating physiological pulse pressure in the pulmonary circulation by modulating the speed of a right ventricular assist device (RVAD) in a mock circulation loop. A rectangular pulse profile with predetermined pulse width has been implemented as the pump speed pattern with two different phase shifts (0% and 50%) with respect to the ventricular contraction. In addition, the performance of the speed modulation strategy has been assessed under different cardiovascular states, including variation in ventricular contractility and pulmonary arterial compliance. Our results indicated that the proposed pulse profile with optimised parameters (Apulse = 10000 rpm and ωmin = 3000 rpm) was able to generate pulmonary arterial pulse pressure within the physiological range (9-15 mmHg) while avoiding undesirable pump backflow under both co- and counter-pulsation modes. As compared to co-pulsation, stroke work was reduced by over 44% under counter-pulsation, suggesting that mechanical workload of the right ventricle can be efficiently mitigated through counter-pulsing the pump speed. Furthermore, our results showed that improved ventricular contractility could potentially lead to higher risk of ventricular suction and pump backflow, while stiffening of the pulmonary artery resulted in increased pulse pressure. In conclusion, the proposed speed modulation strategy produces pulsatile hemodynamics, which is more physiologic than continuous blood flow. The findings also provide valuable insight into the interaction between RVAD speed modulation and the pulmonary circulation under various cardiovascular states.

  10. Generation of tunable and pulsatile concentration gradients via microfluidic network

    KAUST Repository

    Zhou, Bingpu

    2014-06-04

    We demonstrate a compact Polydimethylsiloxane microfluidic chip which can quickly generate ten different chemical concentrations simultaneously. The concentration magnitude of each branch can be flexibly regulated based on the flow rate ratios of the two injecting streams. The temporal/pulsatile concentration gradients are achieved by integrating on-chip pneumatic actuated valves controlled by the external signals. The temporal concentration gradients can also be tuned precisely by varying applied frequency and duty cycle of the trigger signal. It is believed that such microdevice will be potentially used for some application areas of producing stable chemical gradients as well as allowing fast, pulsatile gradient transformation in seconds.

  11. Does the location of a vascular loop in the cerebellopontine angle explain pulsatile and non-pulsatile tinnitus?

    International Nuclear Information System (INIS)

    Nowe, V.; Wang, X.L.; Gielen, J.; Goethem, J.Van; Oezsarlak, Oe.; De Schepper, A.M.; Parizel, P.M.; Ridder, D. De; Heyning, P.H.Van de

    2004-01-01

    The purpose was to investigate patients with unexplained pulsatile and non-pulsatile tinnitus by means of MR imaging of the cerebellopontine angle (CPA) and to correlate the clinical subtype of tinnitus with the location of a blood vessel (in the internal auditory canal or at the cisternal part of the VIIIth cranial nerve). Clinical presentation of tinnitus and perceptive hearing loss were correlated. In 47 patients with unexplained tinnitus, an MR examination of the CPA was performed. Virtual endoscopy reconstructions were obtained using a 3D axial thin-section high-resolution heavily T2-weighted gradient echo constructive interference in steady state (CISS) data-set. High-resolution T2-weighted CISS images showed a significantly higher number of vascular loops in the internal auditory canal in patients with arterial pulsatile tinnitus compared to patients with non-pulsatile tinnitus (P<0.00001). Virtual endoscopy images were used to investigate vascular contacts at the cisternal part of the VIIIth cranial nerve in patients with low pitch and high pitch non-pulsatile tinnitus. A significantly different distribution of the vascular contacts (P=0.0320) was found. Furthermore, a correlation between the clinical presentation of non-pulsatile tinnitus (high pitch and low pitch) and the perceptive hearing loss was found (P=0.0235). High-resolution heavily T2-weighted CISS images and virtual endoscopy of the CPA can be used to evaluate whether a vascular contact is present in the internal auditory canal or at the cisternal part of the VIIIth cranial nerve and whether the location of the vascular contact correlates with the clinical subtype of tinnitus. Our findings suggest that there is a tonotopical structure of the cisternal part of the VIIIth cranial nerve. A correlation between the clinical presentation of tinnitus and hearing loss was found. (orig.)

  12. Does the location of a vascular loop in the cerebellopontine angle explain pulsatile and non-pulsatile tinnitus?

    Energy Technology Data Exchange (ETDEWEB)

    Nowe, V; Wang, X L; Gielen, J; Goethem, J Van; Oezsarlak, Oe; De Schepper, A M; Parizel, P M [University of Antwerp, Department of Radiology, Edegem (Belgium); Ridder, D De [University of Antwerp, Department of Neurosurgery, Edegem (Belgium); Heyning, P.H.Van de [University of Antwerp, Department of Otorhinolaryngology, Edegem (Belgium)

    2004-12-01

    The purpose was to investigate patients with unexplained pulsatile and non-pulsatile tinnitus by means of MR imaging of the cerebellopontine angle (CPA) and to correlate the clinical subtype of tinnitus with the location of a blood vessel (in the internal auditory canal or at the cisternal part of the VIIIth cranial nerve). Clinical presentation of tinnitus and perceptive hearing loss were correlated. In 47 patients with unexplained tinnitus, an MR examination of the CPA was performed. Virtual endoscopy reconstructions were obtained using a 3D axial thin-section high-resolution heavily T2-weighted gradient echo constructive interference in steady state (CISS) data-set. High-resolution T2-weighted CISS images showed a significantly higher number of vascular loops in the internal auditory canal in patients with arterial pulsatile tinnitus compared to patients with non-pulsatile tinnitus (P<0.00001). Virtual endoscopy images were used to investigate vascular contacts at the cisternal part of the VIIIth cranial nerve in patients with low pitch and high pitch non-pulsatile tinnitus. A significantly different distribution of the vascular contacts (P=0.0320) was found. Furthermore, a correlation between the clinical presentation of non-pulsatile tinnitus (high pitch and low pitch) and the perceptive hearing loss was found (P=0.0235). High-resolution heavily T2-weighted CISS images and virtual endoscopy of the CPA can be used to evaluate whether a vascular contact is present in the internal auditory canal or at the cisternal part of the VIIIth cranial nerve and whether the location of the vascular contact correlates with the clinical subtype of tinnitus. Our findings suggest that there is a tonotopical structure of the cisternal part of the VIIIth cranial nerve. A correlation between the clinical presentation of tinnitus and hearing loss was found. (orig.)

  13. Carbon monoxide-releasing molecule-3 suppresses Prevotella intermedia lipopolysaccharide-induced production of nitric oxide and interleukin-1β in murine macrophages.

    Science.gov (United States)

    Choi, Eun-Young; Choe, So-Hui; Hyeon, Jin-Yi; Choi, Jeom-Il; Choi, In Soon; Kim, Sung-Jo

    2015-10-05

    This study was performed to analyze the effect of carbon monoxide (CO)-releasing molecule-3 (CORM-3) in alleviating the production of proinflammatory mediators in macrophages treated with lipopolysaccharide (LPS) from Prevotella intermedia, a pathogen associated with periodontal disease, and its possible mechanisms of action. LPS was isolated using the hot phenol-water method. Culture supernatants were assayed for nitric oxide (NO) and interleukin-1β (IL-1β). Gene expression was quantified by real-time PCR, and protein expression by immunoblotting. DNA-binding activities of NF-κB subunits were determined using an ELISA-based kit. CORM-3 suppressed the production of inducible NO synthase (iNOS)-derived NO and IL-1β at both gene transcription and translation levels in P. intermedia LPS-activated RAW264.7 cells. CORM-3 enhanced heme oxygenase-1 (HO-1) expression in cells stimulated with P. intermedia LPS, and inhibition of HO-1 activity by SnPP notably reversed the suppressive effect of CORM-3 on LPS-induced production of NO. LPS-induced phosphorylation of p38 and JNK was not affected by CORM-3. CORM-3 did not influence P. intermedia LPS-induced degradation of IκB-α. Instead, nuclear translocation of NF-κB p65 and p50 subunits was blocked by CORM-3 in LPS-treated cells. In addition, CORM-3 reduced LPS-induced p65 and p50 binding to DNA. Besides, CORM-3 significantly suppressed P. intermedia LPS-induced phosphorylation of STAT1. Overall, this study indicates that CORM-3 suppresses the production of NO and IL-1β in P. intermedia LPS-activated murine macrophages via HO-1 induction and inhibition of NF-κB and STAT1 pathways. The modulation of host inflammatory response by CORM-3 would be an attractive therapeutic approach to attenuate the progression of periodontal disease. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Experimental Investigation of Pulsatile Flow in Circular Tubes

    Czech Academy of Sciences Publication Activity Database

    Adamec, J.; Nožička, J.; Hanus, D.; Kořenář, Josef

    2001-01-01

    Roč. 17, č. 5 (2001), s. 1133-1136 ISSN 0748-4658 Institutional research plan: CEZ:AV0Z2060917 Keywords : pulsatile flow * laminar-turbulent transition * reynolds normal stress Subject RIV: BK - Fluid Dynamics Impact factor: 0.418, year: 2001

  15. Pulsatile thyrotropin secretion in patients with Cushing's syndrome

    NARCIS (Netherlands)

    Adriaanse, R.; Brabant, G.; Endert, E.; Wiersinga, W. M.

    1994-01-01

    Pulsatile and circadian thyrotropin (TSH) secretion were studied in 16 healthy controls and in three patients with Cushing's syndrome who were studied twice (before and after treatment). Blood was sampled every 10 minutes over 24 hours for TSH (immunoradiometric assay [IRMA]). Mean 24-hour TSH in

  16. Leaback of Pulsatile Flow of Particle Fluid Suspension Model of ...

    African Journals Online (AJOL)

    Leaback of Pulsatile Flow of Particle Fluid Suspension Model of Blood Under Periodic Body Acceleration. ... The variation in body acceleration amplitude though affects the velocity profile in the capillary tubes, it has no effect on the leakback in the tubes. Leakback is mainly determined by the balance of the viscous drag and ...

  17. Pulsatile versus steady infusions for hepatic artery chemotherapy

    International Nuclear Information System (INIS)

    Kim, E.E.; Haynie, T.P.; Wright, K.C.; Chaynsangavej, C.; Gianturco, C.; Lamki, L.; Wallace, S.

    1984-01-01

    Hepatic artery chemotherapy for unresectable liver tumors requires an even distribution of the drugs in the tumor or vascular bed. This cannot be determined angiographically because the drugs are infused at a much lower rate than the contrast media. It is easy, however, to determine the quality of the perfusion by injecting a small volume of Tc-99m MAA in one of the side ports while chemotherapeutic agent is being infused at the same rate. Usually this shows a uniform, satisfactory distribution of isotope. Occasionally, however, some areas fail to receive Tc-99m in spite of what appears to be a good position of the catheter tip. Since ''streaming'' of the infused drugs has been blamed for their uneven distribution, the authors decided to compare the usual steady flow infusions with infusions made pulsatile by the addition of a pulsing device (Gianturco Pump) attached to the infusion tubing. Eighty-three patients were studied with steady as well as pulsatile infusions. In 16 of these patients the perfusion pattern was definitely changed by the pulsatile infusion. In one patient the pulsatile mode resulted in an unwanted gastric perfusion. In 5 patients the distribution was improved in one hepatic lobe and in 10 patients it was improved in both lobes. These results show that hepatic artery perfusions can occasionally be improved by pulsing the infusate. However, pulsing can produce the unwanted perfusion of extra-hepatic areas

  18. In vitro differentiation of human monocytes to macrophages: change of PDE profile and its relationship to suppression of tumour necrosis factor-α release by PDE inhibitors

    Science.gov (United States)

    Gantner, Florian; Kupferschmidt, Rochus; Schudt, Christian; Wendel, Albrecht; Hatzelmann, Armin

    1997-01-01

    During in vitro culture in 10% human AB serum, human peripheral blood monocytes acquire a macrophage-like phenotype. The underlying differentiation was characterized by increased activities of the macrophage marker enzymes unspecific esterase (NaF-insensitive form) and acid phosphatase, as well as by a down-regulation in surface CD14 expression. In parallel, a dramatic change in the phosphodiesterase (PDE) profile became evident within a few days that strongly resembled that previously described for human alveolar macrophages. Whereas PDE1 and PDE3 activities were augmented, PDE4 activity, which represented the major cyclic AMP-hydrolysing activity of peripheral blood monocytes, rapidly declined. Monocytes and monocyte-derived macrophages responded to lipopolysaccharide (LPS) with the release of tumour necrosis factor-α (TNF). In line with the change in CD14 expression, the EC50 value of LPS for induction of TNF release increased from approximately 0.1 ng ml−1 in peripheral blood monocytes to about 2 ng ml−1 in macrophages. Both populations of cells were equally susceptible towards inhibition of TNF release by cyclic AMP elevating agents such as dibutyryl cyclic AMP, prostaglandin E2 (PGE2) or forskolin, which all led to a complete abrogation of TNF production in a concentration-dependent manner and which were more efficient than the glucocorticoid dexamethasone. In monocytes, PDE4 selective inhibitors (rolipram, RP73401) suppressed TNF formation by 80%, whereas motapizone, a PDE3 selective compound, exerted a comparatively weak effect (10–15% inhibition). Combined use of PDE3 plus PDE4 inhibitors resulted in an additive effect and fully abrogated LPS-induced TNF release as did the mixed PDE3/4 inhibitor tolafentrine. In monocyte-derived macrophages, neither PDE3- nor PDE4-selective drugs markedly affected TNF generation when used alone (<15% inhibition), whereas in combination, they led to a maximal inhibition of TNF formation by about 40–50

  19. Pulsatile blood flow, shear force, energy dissipation and Murray's Law

    Directory of Open Access Journals (Sweden)

    Bengtsson Hans-Uno

    2006-08-01

    Full Text Available Abstract Background Murray's Law states that, when a parent blood vessel branches into daughter vessels, the cube of the radius of the parent vessel is equal to the sum of the cubes of the radii of daughter blood vessels. Murray derived this law by defining a cost function that is the sum of the energy cost of the blood in a vessel and the energy cost of pumping blood through the vessel. The cost is minimized when vessel radii are consistent with Murray's Law. This law has also been derived from the hypothesis that the shear force of moving blood on the inner walls of vessels is constant throughout the vascular system. However, this derivation, like Murray's earlier derivation, is based on the assumption of constant blood flow. Methods To determine the implications of the constant shear force hypothesis and to extend Murray's energy cost minimization to the pulsatile arterial system, a model of pulsatile flow in an elastic tube is analyzed. A new and exact solution for flow velocity, blood flow rate and shear force is derived. Results For medium and small arteries with pulsatile flow, Murray's energy minimization leads to Murray's Law. Furthermore, the hypothesis that the maximum shear force during the cycle of pulsatile flow is constant throughout the arterial system implies that Murray's Law is approximately true. The approximation is good for all but the largest vessels (aorta and its major branches of the arterial system. Conclusion A cellular mechanism that senses shear force at the inner wall of a blood vessel and triggers remodeling that increases the circumference of the wall when a shear force threshold is exceeded would result in the observed scaling of vessel radii described by Murray's Law.

  20. Pulsatile fluidic pump demonstration and predictive model application

    International Nuclear Information System (INIS)

    Morgan, J.G.; Holland, W.D.

    1986-04-01

    Pulsatile fluidic pumps were developed as a remotely controlled method of transferring or mixing feed solutions. A test in the Integrated Equipment Test facility demonstrated the performance of a critically safe geometry pump suitable for use in a 0.1-ton/d heavy metal (HM) fuel reprocessing plant. A predictive model was developed to calculate output flows under a wide range of external system conditions. Predictive and experimental flow rates are compared for both submerged and unsubmerged fluidic pump cases

  1. Pulsatility role in cylinder flow dynamics at low Reynolds number

    KAUST Repository

    Qamar, Adnan

    2012-01-01

    We present dynamics of pulsatile flow past a stationary cylinder characterized by three non-dimensional parameters: the Reynolds number (Re), non-dimensional amplitude (A) of the pulsatile flow velocity, and Keulegan-Carpenter number (KC = Uo/Dωc). This work is motivated by the development of total artificial lungs (TAL) device, which is envisioned to provide ambulatory support to patients. Results are presented for 0.2 ≤ A ≤ 0.6 and 0.57 ≤ KC ≤ 2 at Re = 5 and 10, which correspond to the operating range of TAL. Two distinct fluid regimes are identified. In both regimes, the size of the separated zone is much greater than the uniform flow case, the onset of separation is function of KC, and the separation vortex collapses rapidly during the last fraction of the pulsatile cycle. The vortex size is independent of KC, but with an exponential dependency on A. In regime I, the separation point remains attached to the cylinder surface. In regime II, the separation point migrates upstream of the cylinder. Two distinct vortex collapse mechanisms are observed. For A < 0.4 and all KC and Re values, collapse occurs on the cylinder surface, whereas for A > 0.4 the separation vortex detaches from the cylinder surface and collapses at a certain distance downstream of the cylinder. The average drag coefficient is found to be independent of A and KC, and depends only on Re. However, for A > 0.4, for a fraction of the pulsatile cycle, the instantaneous drag coefficient is negative indicating a thrust production. © 2012 American Institute of Physics.

  2. Imaging findings of pulsatile tinnitus caused by sigmoid sinus abnormalities

    International Nuclear Information System (INIS)

    Liang Xihong; Wang Zhenchang; Gong Shusheng; Xia Yin; Wang Zhengyu; Yang Bentao; Yan Fei; Li Jing; Xian Junfang; Chen Guangli

    2010-01-01

    Objective: To study a rare CT finding of pulsatile tinnitus (PT) caused by sigmoid sinus abnormalities. Methods: The imaging data of PT caused by sigmoid sinus abnormalities were analyzed retrospectively in 15 patients (15 female). The median age was 45 years (24 to 63 years). The duration of persistence pulsatile tinnitus was from 0.5 year to 36.0 years (median time, 2.0 years). The tinnitus was at left side in 5 patients and right side in 10 patients. Fifteen patients underwent HRCT of the temporal bone. Of them, 12 patients underwent cerebral CT angiography and CT venogram (CTA/CTV), and 9 patients underwent cerebral digital subtraction angiography (DSA). Nine patients underwent transmastoid reconstruction surgery of the sigmoid sinus. Of them, the tinnitus was at left side in 2 patients and right side in 7 patients. Paired rank sum test was used to compare the cross-sectional area of the sigmoid sinus of the tinnitus side and normal side.Results: On HRCT, foca bony coarse defect is shown in the anterior sigmoid wall in 11 patients and anterolateral sigmoid wall in 4 patients. On CTA/CTV, the sigmoid sinus focally protuded into the adjacent mastoid air cells and formed diverticulum in 10 patients. The pulsatile tinnitus disappeared immediately after transmastoid reconstruction surgery of the sigmoid sinus in all 9 patients. The cross-sectional area of the sigmoid sinus of the tinnitus side was 100.6 (41.5-96.2)mm 2 , it was 77.0 (92.1-122.4)mm 2 in the nonmal side (Z=2.158, P=0.031). Conclusion: Focal bony defect of the sigmoid wall with sigmoid sinus diverticula is one of the causes which lead to pulsatile tinnitus, which can be easily identified by imaging examination. (authors)

  3. Imaging findings of pulsatile tinnitus caused by sigmoid sinus abnormalities

    Energy Technology Data Exchange (ETDEWEB)

    Xihong, Liang; Zhenchang, Wang; Shusheng, Gong; Yin, Xia; Zhengyu, Wang; Bentao, Yang; Fei, Yan; Jing, Li; Junfang, Xian; Guangli, Chen [Department of Radiology, Beijing Tongren Hospital, Capital University of Medical Science, Beijing (China)

    2010-04-15

    Objective: To study a rare CT finding of pulsatile tinnitus (PT) caused by sigmoid sinus abnormalities. Methods: The imaging data of PT caused by sigmoid sinus abnormalities were analyzed retrospectively in 15 patients (15 female). The median age was 45 years (24 to 63 years). The duration of persistence pulsatile tinnitus was from 0.5 year to 36.0 years (median time, 2.0 years). The tinnitus was at left side in 5 patients and right side in 10 patients. Fifteen patients underwent HRCT of the temporal bone. Of them, 12 patients underwent cerebral CT angiography and CT venogram (CTA/CTV), and 9 patients underwent cerebral digital subtraction angiography (DSA). Nine patients underwent transmastoid reconstruction surgery of the sigmoid sinus. Of them, the tinnitus was at left side in 2 patients and right side in 7 patients. Paired rank sum test was used to compare the cross-sectional area of the sigmoid sinus of the tinnitus side and normal side.Results: On HRCT, foca bony coarse defect is shown in the anterior sigmoid wall in 11 patients and anterolateral sigmoid wall in 4 patients. On CTA/CTV, the sigmoid sinus focally protuded into the adjacent mastoid air cells and formed diverticulum in 10 patients. The pulsatile tinnitus disappeared immediately after transmastoid reconstruction surgery of the sigmoid sinus in all 9 patients. The cross-sectional area of the sigmoid sinus of the tinnitus side was 100.6 (41.5-96.2)mm{sup 2}, it was 77.0 (92.1-122.4)mm{sup 2} in the nonmal side (Z=2.158, P=0.031). Conclusion: Focal bony defect of the sigmoid wall with sigmoid sinus diverticula is one of the causes which lead to pulsatile tinnitus, which can be easily identified by imaging examination. (authors)

  4. Closing in on the Mechanisms of Pulsatile Insulin Secretion.

    Science.gov (United States)

    Bertram, Richard; Satin, Leslie S; Sherman, Arthur S

    2018-03-01

    Insulin secretion from pancreatic islet β-cells occurs in a pulsatile fashion, with a typical period of ∼5 min. The basis of this pulsatility in mouse islets has been investigated for more than four decades, and the various theories have been described as either qualitative or mathematical models. In many cases the models differ in their mechanisms for rhythmogenesis, as well as other less important details. In this Perspective, we describe two main classes of models: those in which oscillations in the intracellular Ca 2+ concentration drive oscillations in metabolism, and those in which intrinsic metabolic oscillations drive oscillations in Ca 2+ concentration and electrical activity. We then discuss nine canonical experimental findings that provide key insights into the mechanism of islet oscillations and list the models that can account for each finding. Finally, we describe a new model that integrates features from multiple earlier models and is thus called the Integrated Oscillator Model. In this model, intracellular Ca 2+ acts on the glycolytic pathway in the generation of oscillations, and it is thus a hybrid of the two main classes of models. It alone among models proposed to date can explain all nine key experimental findings, and it serves as a good starting point for future studies of pulsatile insulin secretion from human islets. © 2018 by the American Diabetes Association.

  5. Development of a gastroretentive pulsatile drug delivery platform.

    Science.gov (United States)

    Thitinan, Sumalee; McConville, Jason T

    2012-04-01

    To develop a novel gastroretentive pulsatile drug delivery platform by combining the advantages of floating dosage forms for the stomach and pulsatile drug delivery systems. A gastric fluid impermeable capsule body was used as a vessel to contain one or more drug layer(s) as well as one or more lag-time controlling layer(s). A controlled amount of air was sealed in the innermost portion of the capsule body to reduce the overall density of the drug delivery platform, enabling gastric floatation. An optimal mass fill inside the gastric fluid impermeable capsule body enabled buoyancy in a vertical orientation to provide a constant surface area for controlled erosion of the lag-time controlling layer. The lag-time controlling layer consisted of a swellable polymer, which rapidly formed a gel to seal the mouth of capsule body and act as a barrier to gastric fluid ingress. By varying the composition of the lag-time controlling layer, it was possible to selectively program the onset of the pulsatile delivery of a drug. This new delivery platform offers a new method of delivery for a variety of suitable drugs targeted in chronopharmaceutical therapy. This strategy could ultimately improve drug efficacy and patient compliance, and reduce harmful side effects by scaling back doses of drug administered. © 2012 The Authors. JPP © 2012 Royal Pharmaceutical Society.

  6. The use of gonadotrophin-releasing hormone antagonists in polycystic ovarian disease.

    Science.gov (United States)

    Lubin, V; Charbonnel, B; Bouchard, P

    1998-12-01

    Polycystic ovarian disease (PCOD) is characterized by anovulation, eventually high luteinizing hormone (LH) levels, with increased LH pulse frequency, and hyperandrogenism. As the aetiology of the disease is still unknown, gonadotrophin-releasing hormone (GnRH) antagonists, competitive inhibitors of GnRH for its receptor, are interesting tools in order to study and treat the role of increased LH levels and pulse frequency in this disease. Their administration provokes a rapid decrease in bioactive and immunoactive LH followed by a slower decrease in follicle-stimulating hormone (FSH). In patients with PCOD, the suppression of gonadotrophin secretion eradicates the symptoms of the disease as long as the treatment lasts. Several authors have suggested that increased plasma LH levels have deleterious effects on the fertility of women with PCOD. Indeed, fewer spontaneous pregnancies with more miscarriages are observed when plasma LH levels are high. Assisted reproduction techniques such as in vitro fertilization (IVF) have provided other clues to the role of the LH secretory pattern in women with PCOD. The number of oocytes retrieved, the fertilization rate and the cleavage rate are lower in PCOD patients undergoing IVF and this is inversely correlated with FSH:LH ratio. These abnormalities are corrected when endogenous secretion of LH is suppressed. On the other hand, implantation and pregnancy rates after IVF are similar to those observed in control women. New GnRH antagonists are devoid of side effects and suppress LH secretion within a few hours without a flare-up effect. This action lasts for 10-100 hours. When GnRH antagonists are associated with i.v. pulsatile GnRH, this combination both suppresses the effect of endogenous GnRH and because of the competition for GnRH receptors restores a normal frequency of LH secretion. We have studied two women with PCOD, administering first 10 mg s.c. every 72 hours for 7 days of the GnRH antagonist Nal-Glu, then adding on

  7. SHP-1, a novel peptide isolated from seahorse inhibits collagen release through the suppression of collagenases 1 and 3, nitric oxide products regulated by NF-kappaB/p38 kinase.

    Science.gov (United States)

    Ryu, BoMi; Qian, Zhong-Ji; Kim, Se-Kwon

    2010-01-01

    Considerable efforts have been taken to identify natural peptides as potential bioactive substances. In this study, novel peptide (SHP-1) derived from seahorse (Hippocampus, Syngnathidae) hydrolysate was explored for its inhibitory effects on collagen release in arthritis with the investigation of its underlying mechanism of action. The efficacy of SHP-1 was determined on cartilage protective effects such as inhibition of collagen and GAG release. SHP-1 was able to suppress not only the expression of collagenases 1 and 3, but also the production of NO via down-regulation of iNOS. However, it presented an irrelevant effect on the level of GAG release in chondrocytic and osteoblastic cells. Inhibition of collagen release by SHP-1 is associated with restraining the phosphorylation of NF-kappaB and p38 kinase cascade. Therefore, it could be suggested that SHP-1 has a potential to be used in arthritis treatment.

  8. Neonatal testosterone suppresses a neuroendocrine pulse generator required for reproduction

    Science.gov (United States)

    Israel, Jean-Marc; Cabelguen, Jean-Marie; Le Masson, Gwendal; Oliet, Stéphane H.; Ciofi, Philippe

    2014-02-01

    The pituitary gland releases hormones in a pulsatile fashion guaranteeing signalling efficiency. The determinants of pulsatility are poorly circumscribed. Here we show in magnocellular hypothalamo-neurohypophyseal oxytocin (OT) neurons that the bursting activity underlying the neurohormonal pulses necessary for parturition and the milk-ejection reflex is entirely driven by a female-specific central pattern generator (CPG). Surprisingly, this CPG is active in both male and female neonates, but is inactivated in males after the first week of life. CPG activity can be restored in males by orchidectomy or silenced in females by exogenous testosterone. This steroid effect is aromatase and caspase dependent, and is mediated via oestrogen receptor-α. This indicates the apoptosis of the CPG network during hypothalamic sexual differentiation, explaining why OT neurons do not burst in adult males. This supports the view that stereotypic neuroendocrine pulsatility is governed by CPGs, some of which are subjected to gender-specific perinatal programming.

  9. Heat Transfer to Pulsatile Slip Flow in a Porous Channel Filled With ...

    African Journals Online (AJOL)

    This paper investigate the effect of slip on the hydromagnetic pulsatile flow through a porous channel filled with saturated porous medium with time dependent boundary condition on the heated wall. Based on the pulsatile flow nature, the dimensionless flow governing equations are resolved to harmonic and non-harmonic ...

  10. Effect of Acute Resistance Exercise on Carotid Artery Stiffness and Cerebral Blood Flow Pulsatility

    Directory of Open Access Journals (Sweden)

    Wesley K Lefferts

    2014-03-01

    Full Text Available Arterial stiffness is associated with cerebral flow pulsatility. Arterial stiffness increases following acute resistance exercise (RE. Whether this acute RE-induced vascular stiffening affects cerebral pulsatility remains unknown. Purpose: To investigate the effects of acute RE on common carotid artery (CCA stiffness and cerebral blood flow velocity (CBFv pulsatility. Methods: Eighteen healthy men (22 ± 1 yr; 23.7 ± 0.5 kg∙m-2 underwent acute RE (5 sets, 5-RM bench press, 5 sets 10-RM bicep curls with 90 s rest intervals or a time control condition (seated rest in a randomized order. CCA stiffness (β-stiffness, Elastic Modulus (Ep and hemodynamics (pulsatility index, forward wave intensity and reflected wave intensity were assessed using a combination of Doppler ultrasound, wave intensity analysis and applanation tonometry at baseline and 3 times post-RE. CBFv pulsatility index was measured with transcranial Doppler at the middle cerebral artery (MCA. Results: CCA β-stiffness, Ep and CCA pulse pressure significantly increased post-RE and remained elevated throughout post-testing (p 0.05. There were significant increases in forward wave intensity post-RE (p0.05. Conclusion: Although acute RE increases CCA stiffness and pressure pulsatility, it may not affect CCA or MCA flow pulsatility. Increases in pressure pulsatility may be due to increased forward wave intensity and not pressure from wave reflections.

  11. Active spice-derived components can inhibit inflammatory responses of adipose tissue in obesity by suppressing inflammatory actions of macrophages and release of monocyte chemoattractant protein-1 from adipocytes.

    Science.gov (United States)

    Woo, Hae-Mi; Kang, Ji-Hye; Kawada, Teruo; Yoo, Hoon; Sung, Mi-Kyung; Yu, Rina

    2007-02-13

    Inflammation plays a key role in obesity-related pathologies such as cardiovascular disease, type II diabetes, and several types of cancer. Obesity-induced inflammation entails the enhancement of the recruitment of macrophages into adipose tissue and the release of various proinflammatory proteins from fat tissue. Therefore, the modulation of inflammatory responses in obesity may be useful for preventing or ameliorating obesity-related pathologies. Some spice-derived components, which are naturally occurring phytochemicals, elicit antiobesity and antiinflammatory properties. In this study, we investigated whether active spice-derived components can be applied to the suppression of obesity-induced inflammatory responses. Mesenteric adipose tissue was isolated from obese mice fed a high-fat diet and cultured to prepare an adipose tissue-conditioned medium. Raw 264.7 macrophages were treated with the adipose tissue-conditioned medium with or without active spice-derived components (i.e., diallyl disulfide, allyl isothiocyanate, piperine, zingerone and curcumin). Chemotaxis assay was performed to measure the degree of macrophage migration. Macrophage activation was estimated by measuring tumor necrosis factor-alpha (TNF-alpha), nitric oxide, and monocyte chemoattractant protein-1 (MCP-1) concentrations. The active spice-derived components markedly suppressed the migration of macrophages induced by the mesenteric adipose tissue-conditioned medium in a dose-dependent manner. Among the active spice-derived components studied, allyl isothiocyanate, zingerone, and curcumin significantly inhibited the cellular production of proinflammatory mediators such as TNF-alpha and nitric oxide, and significantly inhibited the release of MCP-1 from 3T3-L1 adipocytes. Our findings suggest that the spice-derived components can suppress obesity-induced inflammatory responses by suppressing adipose tissue macrophage accumulation or activation and inhibiting MCP-1 release from adipocytes

  12. Experimental and theoretical investigations of Lantana camara oil diffusion from polyacrylonitrile membrane for pulsatile drug delivery system

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Vivek [Department of Chemistry, Indian Institute of Science Education and Research (IISER), Pune 411008 (India); Balasubramanian, K., E-mail: meetkbs@gmail.com [Department of Materials Engineering, Defence Institute of Advance Technology (DIAT), Ministry of Defence, Girinagar, Pune 411025 (India)

    2014-08-01

    Porous composite membrane of polyacrylonitrile (PAN) and Lantana camara essential oil was synthesized by solvent casting method. Stability of oil in PAN solution was measured by XiGo nano tool indicating constant relaxation time of 1487 time/s. Pore size of few microns confirmed by electron microscopy was supported by atomic force microscopy indicating roughness factor of 0.9 nm. Contact angle of 2° inveterates superhydrophilicity of the composite membrane. Membrane showed excellent antibacterial activity against both Gram-positive Bacillus subtilis and Gram-negative Escherichia coli with a 7–10 mm zone of inhibition. In vitro release of Lantana oil from the composite membrane was carried out in isotonic phosphate buffer solution (pH = 7.4). Lantana oil was released for 9 h, lag time of 3 h with constant 33% release confirmed PAN membranes as potential system for pulsatile drug delivery applications. Diffusion of E-caryophyllene (antibacterial component of oil) which was studied through molecular simulation using Material Studio software ensued diffusion coefficient value of 1.11 ∗ 10{sup −9} m{sup 2}/s. Biocompatibility of the composite membrane was assessed by mouse embryonic fibroblast cell line (NIH 3T3) through MTT assay indicating more than 91% viable cell even at 200 μg/mL concentration. Such membranes can be efficiently used in biomedical applications as antibacterial and antifungal agent. - Highlights: • Pulsatile release • Lantana oil–PAN composite membrane as antibacterial material • Enhanced bactericidal activity of the membrane.

  13. Induction of pulsatile secretion of leptin in horses following thyroidectomy.

    Science.gov (United States)

    Buff, Preston R; Messer, Nat T; Cogswell, Andria M; Wilson, David A; Johnson, Philip J; Keisler, Duane H; Ganjam, Venkataseshu K

    2007-02-01

    Endocrine characteristics of Quarter Horse-type mares were determined during a 68 h feed deprivation and again in the same mares following surgical thyroidectomy (THX). A crossover experimental design was implemented, in which mares received brome hay available ad libitum (FED) or were food deprived (RES) for 68 h. Blood samples were collected every 20 min for 48 h, beginning 20 h after the onset of food deprivation. Concentrations of triiodothyronine and thyroxine were undetectable post-THX. Plasma concentrations of thyrotropin were greater post-THX versus pre-THX (P<0 x 001). Plasma concentrations of leptin were greater in the THX FED group than in the THX RES group (P<0 x 01). The existence of leptin pulse secretion was found only in post-THX compared with the same horses pre-THX (P=0 x 02). We theorize that non-pulsatile secretion of leptin may have contributed to the survival of this species, as it evolved in the regions of seasonal availability of food. Lack of pulsatile secretion of leptin may contribute to the accumulation of energy stores by modulating leptin sensitivity.

  14. A study of doppler waveform using pulsatile flow model

    International Nuclear Information System (INIS)

    Chung, Hye Won; Chung, Myung Jin; Park, Jae Hyung; Chung, Jin Wook; Lee, Dong Hyuk; Min, Byoung Goo

    1997-01-01

    Through the construction of a pulsatile flow model using an artificial heart pump and stenosis to demonstrate triphasic Doppler waveform, which simulates in vivo conditions, and to evaluate the relationship between Doppler waveform and vascular compliance. The flow model was constructed using a flowmeter, rubber tube, glass tube with stenosis, and artificial heart pump. Doppler study was carried out at the prestenotic, poststenotic, and distal segments;compliance was changed by changing the length of the rubber tube. With increasing proximal compliance, Doppler waveforms show decreasing peak velocity of the first phase and slightly delayed acceleration time, but the waveform itself did not change significantly. Distal compliance influenced the second phase, and was important for the formation of pulsus tardus and parvus, which without poststenotic vascular compliance, did not develop. The peak velocity of the first phase was inversely proportional to proximal compliance, and those of the second and third phases were directly proportional to distal compliance. After constructing this pulsatile flow model, we were able to explain the relationship between vascular compliance and Doppler waveform, and also better understand the formation of pulsus tardus and parvus

  15. Endocrine dynamics during pulsatile GnRH administration in patients with hypothalamic amenorrhea and polycystic ovarian disease.

    Science.gov (United States)

    Rossmanith, W G; Wirth, U; Benz, R; Wolf, A S

    1989-01-01

    The LH secretory patterns and ovarian endocrine responses have been determined during pulsatile gonadotropin-releasing hormone (GnRH) administration for induction of ovulation in patients with hypothalamic amenorrhea (HA). However, until now these endocrine dynamics during GnRH therapy have not been thoroughly investigated in patients with polycystic ovarian disease (PCOD). Seven patients with HA and 4 patients with PCOD have therefore been studied to determine changes in LH pulsatile activity and in serum sex steroid levels in response to chronic intermittent GnRH stimulation. GnRH was administered intravenously (5-10 micrograms/90 minutes) by means of a portable infusion pump. Blood samples were obtained at 15-minute intervals for 4 hours on the day before the start of GnRH stimulation (control day) and on treatment days 5, 10 and 15. LH was determined in all samples and FSH, serum androgens and estrogens were measured in baseline samples by RIA. While 8 (62%) ovulations and 5 conceptions were observed in 13 treatment cycles in patients with HA, no ovulations were achieved during 9 treatment cycles in patients with PCOD. On the control day significantly (p less than 0.05) higher basal LH and testosterone (T) levels and significantly (p less than 0.05) lower FSH levels were found in the PCOD patients. The LH pulsatile profiles of the PCOD patients showed significantly (p less than 0.05) higher pulse amplitudes and areas under the curve (integrated responses). Pulsatile GnRH administration induced a significant (p less than 0.05) increase in LH pulse amplitudes in both HA and PCOD patients, and also increased (p less than 0.05) the integrated responses in patients with HA. During the GnRH stimulation, the LH interpulse intervals of both HA and PCOD patients were found to be similar to the frequency in which exogenous GnRH was administered. FSH levels rose continuously (p less than 0.001) during stimulation in patients with HA, but remained unchanged in patients

  16. Doppler of the uterine arteries combined with endometrial thickness correlate well with the degree of pituitary suppression in women treated with long-acting GnRH agonists.

    Science.gov (United States)

    Geber, Selmo; Vaintraub, Marco Túlio; Rotschild, Gisele; Sampaio, Marcos

    2013-02-01

    The aim of this study was to evaluate the use of Doppler velocimetry of the uterine arteries and its association to endometrial thickness as a method to confirm pituitary suppression after administration of gonadotropin-releasing hormone analogues in assisted reproduction treatment cycles. A total of 70 patients using gonadotropin-releasing hormone analogues for pituitary suppression for in vitro fertilization treatment were studied. To confirm down-regulation, serum estradiol levels and endometrial thickness were evaluated 10 days after gonadotropin-releasing hormone analogues administration. When estradiol was 30 pg/ml the mean PI was 2.22 ± 0.8 (p = 0.005). For the patients who had endometrial thickness ≤5 mm the mean PI was 2.86 ± 0.82 and for those with endometrial thickness >5 mm the mean PI was 2.17 ± 0.79 (p = 0.004). Using a cut-off point of 2.51 for the pulsatility index, to compare to estradiol levels, we observed a sensitivity of 72.7 % and specificity of 71 %. The combination of Doppler velocimetric and endometrial thickness showed a sensitivity of 94 % and specificity of 82.3 %. Doppler velocimetric analysis of the uterine arteries can be an important tool in the diagnosis of the down-regulation after the use of gonadotropin-releasing hormone analogues and might help simplify assisted reproduction programmes.

  17. Extrinsic nerves are not involved in branchial 5-HT dynamics or pulsatile urea excretion in Gulf toadfish, Opsanus beta.

    Science.gov (United States)

    Cartolano, Maria C; Amador, Molly H B; Tzaneva, Velislava; Milsom, William K; McDonald, M Danielle

    2017-12-01

    Gulf toadfish (Opsanus beta) can switch from continuously excreting ammonia as their primary nitrogenous waste to excreting predominantly urea in distinct pulses. Previous studies have shown that the neurotransmitter serotonin (5-HT) is involved in controlling this process, but it is unknown if 5-HT availability is under central nervous control or if the 5-HT signal originates from a peripheral source. Following up on a previous study, cranial nerves IX (glossopharyngeal) and X (vagus) were sectioned to further characterize their role in controlling pulsatile urea excretion and 5-HT release within the gill. In contrast to an earlier study, nerve sectioning did not result in a change in urea pulse frequency. Total urea excretion, average pulse size, total nitrogen excretion, and percent ureotely were reduced the first day post-surgery in nerve-sectioned fish but recovered by 72h post-surgery. Nerve sectioning also had no effect on toadfish urea transporter (tUT), 5-HT transporter (SERT), or 5-HT 2A receptor mRNA expression or 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) abundance in the gill, all of which were found consistently across the three gill arches except 5-HIAA, which was undetectable in the first gill arch. Our findings indicate that the central nervous system does not directly control pulsatile urea excretion or local changes in gill 5-HT and 5-HIAA abundance. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Modeling of pulsatile flow-dependent nitric oxide regulation in a realistic microvascular network.

    Science.gov (United States)

    Wang, Ruofan; Pan, Qing; Kuebler, Wolfgang M; Li, John K-J; Pries, Axel R; Ning, Gangmin

    2017-09-01

    Hemodynamic pulsatility has been reported to regulate microcirculatory function. To quantitatively assess the impact of flow pulsatility on the microvasculature, a mathematical model was first developed to simulate the regulation of NO production by pulsatile flow in the microcirculation. Shear stress and pressure pulsatility were selected as regulators of endothelial NO production and NO-dependent vessel dilation as feedback to control microvascular hemodynamics. The model was then applied to a real microvascular network of the rat mesentery consisting of 546 microvessels. As compared to steady flow conditions, pulsatile flow increased the average NO concentration in arterioles from 256.8±93.1nM to 274.8±101.1nM (Pflow as compared to steady flow conditions. Network perfusion and flow heterogeneity were improved under pulsatile flow conditions, and vasodilation within the network was more sensitive to heart rate changes than pulse pressure amplitude. The proposed model simulates the role of flow pulsatility in the regulation of a complex microvascular network in terms of NO concentration and hemodynamics under varied physiological conditions. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Pulsatile flow of viscous and viscoelastic fluids in constricted tubes

    Energy Technology Data Exchange (ETDEWEB)

    Javadzadegan, A.; Esmaeili, M.; Majidi, S. [University of Tehran, Tehran (Iran, Islamic Republic of); Fakhimghanbarzadeh, B. [Sharif University of Technology, Tehran (Iran, Islamic Republic of)

    2009-09-15

    The unsteady flow of blood through stenosed artery, driven by an oscillatory pressure gradient, is studied. An appropriate shape of the time-dependent stenoses which are overlapped in the realm of the formation of arterial narrowing is constructed mathematically. A mathematical model is developed by treating blood as a non-Newtonian fluid characterized by the Oldroyd-B and Cross models. A numerical scheme has been used to solve the unsteady nonlinear Navier- stokes equations in cylindrical coordinate system governing flow, assuming axial symmetry under laminar flow condition so that the problem effectively becomes two-dimensional. Finite difference technique was used to investigate the effects of parameters such as pulsatility, non-Newtonian properties and the flow time on the velocity components, the rate of flow, and the wall shear stress through their graphical representations quantitatively at the end of the paper in order to validate the applicability of the present improved mathematical model under consideration

  20. Pulsatile flow of viscous and viscoelastic fluids in constricted tubes

    International Nuclear Information System (INIS)

    Javadzadegan, A.; Esmaeili, M.; Majidi, S.; Fakhimghanbarzadeh, B.

    2009-01-01

    The unsteady flow of blood through stenosed artery, driven by an oscillatory pressure gradient, is studied. An appropriate shape of the time-dependent stenoses which are overlapped in the realm of the formation of arterial narrowing is constructed mathematically. A mathematical model is developed by treating blood as a non-Newtonian fluid characterized by the Oldroyd-B and Cross models. A numerical scheme has been used to solve the unsteady nonlinear Navier- stokes equations in cylindrical coordinate system governing flow, assuming axial symmetry under laminar flow condition so that the problem effectively becomes two-dimensional. Finite difference technique was used to investigate the effects of parameters such as pulsatility, non-Newtonian properties and the flow time on the velocity components, the rate of flow, and the wall shear stress through their graphical representations quantitatively at the end of the paper in order to validate the applicability of the present improved mathematical model under consideration

  1. Mathematical Modelling of CSF Pulsatile Flow in Aqueduct Cerebri.

    Science.gov (United States)

    Czosnyka, Zofia; Kim, Dong-Joo; Balédent, Olivier; Schmidt, Eric A; Smielewski, Peter; Czosnyka, Marek

    2018-01-01

    The phase-contrast MRI technique permits the non-invasive assessment of CSF movements in cerebrospinal fluid cavities of the central nervous system. Of particular interest is pulsatile cerebrospinal fluid (CSF) flow through the aqueduct cerebri. It is allegedly increased in hydrocephalus, having potential diagnostic value, although not all scientific reports contain unequivocally positive conclusions. For the mathematical simulation of CSF flow, we used a computational model of cerebrospinal blood/fluid circulation designed by a former student as his PhD project. With this model, cerebral blood flow and CSF may be simulated in various vessels using a system of non-linear differential equations as time-varying signals. The amplitude of CSF flow seems to be positively related to the amplitude of pulse waveforms of intracranial pressure (ICP) in situations where mean ICP increases, such as during simulated infusion tests and following step increases of resistance to CSF outflow. An additional positive association between the pulse amplitude of ICP and CSF flow can be seen during simulated increases in the amplitude of arterial pulses (without changes in mean arterial pressure, MAP). The opposite effect can be observed during step increases in the resistance of the aqueduct cerebri and with decreasing elasticity of the system, where the CSF flow amplitude and the ICP pulse amplitude are related inversely. Vasodilatation caused by both gradual decreases in MAP and by increases in PaCO2 provokes an elevation in the observed amplitude of pulsatile CSF flow. Preliminary results indicate that the pulsations of CSF flow may carry information about both CSF-circulatory and cerebral vasogenic components. In most cases, the pulsations of CSF flow are positively related to the pulse amplitudes of both arterial pressure and ICP and to a degree of cerebrovascular dilatation.

  2. Combining the Sterile Insect Technique with Wolbachia-Based Approaches: II--A Safer Approach to Aedes albopictus Population Suppression Programmes, Designed to Minimize the Consequences of Inadvertent Female Release.

    Directory of Open Access Journals (Sweden)

    Dongjing Zhang

    Full Text Available Due to the absence of a perfect method for mosquito sex separation, the combination of the sterile insect technique and the incompatible insect technique is now being considered as a potentially effective method to control Aedes albopictus. In this present study first we examine the minimum pupal irradiation dose required to induce complete sterility in Wolbachia triple-infected (HC, double-infected (GUA and uninfected (GT female Ae. albopictus. The HC line is a candidate for Ae. albopictus population suppression programmes, but due to the risk of population replacement which characterizes this triple infected line, the individuals to be released need to be additionally irradiated. After determining the minimum irradiation dose required for complete female sterility, we test whether sterilization is sufficient to prevent invasion of the triple infection from the HC females into double-infected (GUA populations. Our results indicate that irradiated Ae. albopictus HC, GUA and GT strain females have decreased fecundity and egg hatch rate when irradiated, inversely proportional to the dose, and the complete sterilization of females can be acquired by pupal irradiation with doses above 28 Gy. PCR-based analysis of F1 and F2 progeny indicate that the irradiated HC females, cannot spread the new Wolbachia wPip strain into a small cage GUA population, released at a 1:5 ratio. Considering the above results, we conclude that irradiation can be used to reduce the risk of population replacement caused by an unintentional release of Wolbachia triple-infected Ae. albopictus HC strain females during male release for population suppression.

  3. The 5-HT(1A) receptor agonist, 8-OH-DPAT, attenuates stress-induced anorexia in conjunction with the suppression of hypothalamic serotonin release in rats.

    Science.gov (United States)

    Shimizu, N; Hori, T; Ogino, C; Kawanishi, T; Hayashi, Y

    2000-12-22

    The effect of the selective 5-HT(1A) receptor agonist 8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) on stress-induced anorexia and serotonin (5-HT) release in the rat hypothalamus was studied with brain microdialysis. Subcutaneous injection of 8-OH-DPAT (1 mg/kg) significantly attenuated the immobilization-induced anorexia for 3 h, but had no effect during the following 9 h. Injection of 8-OH-DPAT itself had no effect on basal release of 5-HT, while it significantly blocked the immobilization-induced 5-HT release in the lateral hypothalamus. The results suggest that 8-OH-DPAT attenuated the stress-induced anorexia through the activation of 5-HT(1A) autoreceptors in dorsal raphe nucleus.

  4. MR imaging of pulsatile CSF movement in hydrocephalus communicans before and after CSF shunt implantation

    International Nuclear Information System (INIS)

    Goldmann, A.; Kunz, U.; Rotermund, F.; Friedrich, J.M.; Schnarkowski, P.

    1992-01-01

    16 patients with hydrocephalus communicans and 5 healthy volunteers were examined to demonstrate the pattern of the pulsatile CSF flow. After implantation of a CSF shunt system the same patients were examined again to show the influence of the shunt on the CSF pulsations. We used a flow-sensitised, cardiac-gated 2D FLASH sequence and analysed the phase and magnitude images. It could be shown that most patients (n=12) had a hyerdynamic pulsatile flow preoperatively. After shunt implantation the pulsatile CSF motion and the clinical symptoms were improved in 8 of these patients. MRI of pulsatile CSF flow movement seems to be a helpful noninvasive tool to estimate the prognosis of a shunt implantation in patients with hydrocephalus communicans. (orig.) [de

  5. Measurement of real pulsatile blood flow using X-ray PIV technique with CO2 microbubbles.

    Science.gov (United States)

    Park, Hanwook; Yeom, Eunseop; Seo, Seung-Jun; Lim, Jae-Hong; Lee, Sang-Joon

    2015-03-06

    Synchrotron X-ray imaging technique has been used to investigate biofluid flows in a non-destructive manner. This study aims to investigate the feasibility of the X-ray PIV technique with CO2 microbubbles as flow tracer for measurement of pulsatile blood flows under in vivo conditions. The traceability of CO2 microbubbles in a pulsatile flow was demonstrated through in vitro experiment. A rat extracorporeal bypass loop was used by connecting a tube between the abdominal aorta and jugular vein of a rat to obtain hemodynamic information of actual pulsatile blood flows without changing the hemorheological properties. The decrease in image contrast of the surrounding tissue was also investigated for in vivo applications of the proposed technique. This technique could be used to accurately measure whole velocity field information of real pulsatile blood flows and has strong potential for hemodynamic diagnosis of cardiovascular diseases.

  6. Measurement of real pulsatile blood flow using X-ray PIV technique with CO2 microbubbles

    Science.gov (United States)

    Park, Hanwook; Yeom, Eunseop; Seo, Seung-Jun; Lim, Jae-Hong; Lee, Sang-Joon

    2015-01-01

    Synchrotron X-ray imaging technique has been used to investigate biofluid flows in a non-destructive manner. This study aims to investigate the feasibility of the X-ray PIV technique with CO2 microbubbles as flow tracer for measurement of pulsatile blood flows under in vivo conditions. The traceability of CO2 microbubbles in a pulsatile flow was demonstrated through in vitro experiment. A rat extracorporeal bypass loop was used by connecting a tube between the abdominal aorta and jugular vein of a rat to obtain hemodynamic information of actual pulsatile blood flows without changing the hemorheological properties. The decrease in image contrast of the surrounding tissue was also investigated for in vivo applications of the proposed technique. This technique could be used to accurately measure whole velocity field information of real pulsatile blood flows and has strong potential for hemodynamic diagnosis of cardiovascular diseases. PMID:25744850

  7. DsbA-L prevents obesity-induced inflammation and insulin resistance by suppressing the mtDNA release-activated cGAS-cGAMP-STING pathway

    Science.gov (United States)

    Chronic inflammation in adipose tissue plays a key role in obesity-induced insulin resistance. However, the mechanisms underlying obesity-induced inflammation remain elusive. Here we show that obesity promotes mtDNA release into the cytosol, where it triggers inflammatory responses by activating the...

  8. Suppression of MMP activity in bovine cartilage explants cultures has little if any effect on the release of aggrecanase-derived aggrecan fragments

    DEFF Research Database (Denmark)

    Wang, Bijue; Chen, Pingping; Jensen, Anne-Christine Bay

    2009-01-01

    BACKGROUND: Progressive loss of articular cartilage is a central hallmark in many joint disease, however, the relative importance of individual proteolytic pathways leading to cartilage erosion is at present unknown. We therefore investigated the time-dependant release ex vivo of MMP- and aggreca......BACKGROUND: Progressive loss of articular cartilage is a central hallmark in many joint disease, however, the relative importance of individual proteolytic pathways leading to cartilage erosion is at present unknown. We therefore investigated the time-dependant release ex vivo of MMP......- and aggrecanase-derived fragments of aggrecan and type II collagen into the supernatant of bovine cartilage explants cultures using neo-epitope specific immunoassays, and to associate the release of these fragments with the activity of proteolytic enzymes using inhibitors. FINDINGS: Bovine cartilage explants were...... cultured in the presence or absence of the catabolic cytokines oncostatin M (OSM) and tumor necrosis factor alpha (TNFalpha). In parallel, explants were co-cultured with protease inhibitors such as GM6001, TIMP1, TIMP2 and TIMP3. Fragments released into the supernatant were determined using a range of neo...

  9. Effectiveness, pharmacokinetics, and safety of a new sustained-release leuprolide acetate 3.75-mg depot formulation for testosterone suppression in patients with prostate cancer: a Phase III, open-label, international multicenter study.

    Science.gov (United States)

    Marberger, Michael; Kaisary, Amir V; Shore, Neal D; Karlin, Gary S; Savulsky, Claudio; Mis, Ricard; Leuratti, Chiara; Germa, Josep R

    2010-04-01

    A microencapsulated, sustained-release formulation of leuprolide acetate 3.75 mg has been developed. This study investigated the effectiveness, pharmacokinetics, and safety profile of a 1-month leuprolide acetate 3.75-mg depot formulation for suppressing testosterone concentrations in patients with prostate cancer. This was a Phase III, open-label, international multicenter clinical trial. Patients with prostate cancer who, in the judgment of the investigators, could benefit from androgen deprivation therapy received 6 monthly intramuscular injections of leuprolide acetate 3.75-mg depot. Plasma testosterone concentrations were determined at specific times throughout the study. The primary end point was the proportion of successful patients over the total number of evaluable patients (ie, patients with evaluable testosterone concentrations at all monthly assessments and no missing values due to treatment-related adverse events). Treatment success was defined as testosterone suppression below the clinical castration level (ie, n = 12), showed sustained release of leuprolide from the formulation. Values for AUC(0-t) calculated from day 0 to day 28, days 28 to 56, and days 56 to 84 were 25,976.5 (7892.0), 30,685.5 (9348.4), and 31,030.9 (10,745.0) pg/mL per day, respectively. The most common treatment-related adverse event was hot flashes (45.0% [72/160]). Fatigue, hyperhidrosis, night sweats, and headache each occurred in suppression and was well tolerated throughout the study in this cohort of patients with prostate cancer. ClinicalTrials.gov identifier: NCT00128531.

  10. Cerebrovascular blood oxygenation level dependent pulsatility at baseline and following acute exercise among healthy adolescents.

    Science.gov (United States)

    Theyers, Athena E; Goldstein, Benjamin I; Metcalfe, Arron Ws; Robertson, Andrew D; MacIntosh, Bradley J

    2018-01-01

    Arterial stiffness is linked to cerebral small vessel damage and neurodegeneration, but barriers to accessing deep cerebrovascular anatomy limit our ability to assess the brain. This study describes an adaptation of a cardiac-related scrubbing method as a means of generating blood oxygenation level-dependent pulsatility maps based on the cardiac cycle. We examine BOLD pulsatility at rest, based on the non-parametric deviation from null metric, as well as changes following acute physiological stress from 20 min of moderate-intensity cycling in 45 healthy adolescents. We evaluate the influence of repetition time (TR) and echo time (TE) using simulated and multi-echo empirical data, respectively. There were tissue-specific and voxel-wise BOLD pulsatility decreases 20 min following exercise cessation. BOLD pulsatility detection was comparable over a range of TR and TE values when scan volumes were kept constant; however, short TRs (≤500 ms) and TEs (∼14 ms) acquisitions would yield the most efficient detection. Results suggest cardiac-related BOLD pulsatility may represent a robust and easily adopted method of mapping cerebrovascular pulsatility with voxel-wise resolution.

  11. Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects

    Energy Technology Data Exchange (ETDEWEB)

    Waahlin, Anders

    2012-07-01

    During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects.Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation. A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies. The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found. Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile

  12. Cerebral blood flow and intracranial pulsatility studied with MRI: measurement, physiological and pathophysiological aspects

    International Nuclear Information System (INIS)

    Waahlin, Anders

    2012-01-01

    During each cardiac cycle pulsatile arterial blood inflates the vascular bed of the brain, forcing cerebrospinal fluid (CSF) and venous blood out of the cranium. Excessive arterial pulsatility may be part of a harmful mechanism causing cognitive decline among elderly. Additionally, restricted venous flow from the brain is suggested as the cause of multiple sclerosis. Addressing hypotheses derived from these observations requires accurate and reliable investigational methods. This work focused on assessing the pulsatile waveform of cerebral arterial, venous and CSF flows. The overall aim of this dissertation was to explore cerebral blood flow and intracranial pulsatility using MRI, with respect to measurement, physiological and pathophysiological aspects.Two-dimensional phase contrast magnetic resonance imaging (2D PCMRI) was used to assess the pulsatile waveforms of cerebral arterial, venous and CSF flow. The repeatability was assessed in healthy young subjects. The 2D PCMRI measurements of cerebral arterial, venous and CSF pulsatility were generally repeatable but the pulsatility decreased systematically during the investigation. A method combining 2D PCMRI measurements with invasive CSF infusion tests to determine the magnitude and distribution of compliance within the craniospinal system was developed and applied in a group of healthy elderly. The intracranial space contained approximately two thirds of the total craniospinal compliance. The magnitude of craniospinal compliance was less than suggested in previous studies. The vascular hypothesis for multiple sclerosis was tested. Venous drainage in the internal jugular veins was compared between healthy controls and multiple sclerosis patients using 2D PCMRI. For both groups, a great variability in the internal jugular flow was observed but no pattern specific to multiple sclerosis could be found. Relationships between regional brain volumes and potential biomarkers of intracranial cardiac-related pulsatile

  13. 1,5-Anhydro-D-fructose attenuates lipopolysaccharide-induced cytokine release via suppression of NF-κB p65 phosphorylation

    International Nuclear Information System (INIS)

    Meng Xiaojie; Kawahara, Ko-ichi; Nawa, Yuko; Miura, Naoki; Shrestha, Binita; Tancharoen, Salunya; Sameshima, Hisayo; Hashiguchi, Teruto; Maruyama, Ikuro

    2009-01-01

    Lipopolysaccharide (LPS) stimulates macrophages by activating NF-κB, which contributes to the release of tumor necrosis factor (TNF)-α and interleukin (IL)-6. 1,5-anhydro-D-fructose (1,5-AF), a monosaccharide formed from starch and glycogen, exhibits anti-oxidant activity and enhances insulin secretion. This study examined the effects of 1,5-AF on LPS-induced inflammatory reactions and elucidated its molecular mechanisms. Before LPS challenge, mice were pretreated with 1,5-AF (38.5 mg/kg). We found that 1,5-AF pretreatment attenuated cytokine release into the serum, including TNF-α, IL-6 and macrophage chemoattractant protein (MCP)-1. Furthermore, pretreatment with 1,5-AF (500 μg/ml) attenuated cytokine release, and 1,5-AF directly inhibited the nuclear translocalization of the NF-κB p65 subunit in LPS-stimulated murine macrophage-like RAW264.7 cells. This inhibition was responsible for decreased LPS-induced phosphorylation on Ser536 of the NF-κB p65 subunit, which is a posttranslational modification involved in the non-canonical pathway. Collectively, these findings indicate that the anti-inflammatory activity of 1,5-AF occurs via inactivation of NF-κB.

  14. PLATELET ADHESION TO POLYURETHANE UREA UNDER PULSATILE FLOW CONDITIONS

    Science.gov (United States)

    Navitsky, Michael A.; Taylor, Joshua O.; Smith, Alexander B.; Slattery, Margaret J.; Deutsch, Steven; Siedlecki, Christopher A.; Manning, Keefe B.

    2014-01-01

    Platelet adhesion to a polyurethane urea surface is a precursor to thrombus formation within blood-contacting cardiovascular devices, and platelets have been found to adhere strongly to polyurethane surfaces below a shear rate of approximately 500 s−1. The aim of the current work is to determine platelet adhesion properties to the polyurethane urea surface as a function of time varying shear exposure. A rotating disk system is used to study the influence of steady and pulsatile flow conditions (e.g. cardiac inflow and sawtooth waveforms) for platelet adhesion to the biomaterial surface. All experiments retain the same root mean square angular rotation velocity (29.63 rad/s) and waveform period. The disk is rotated in platelet rich bovine plasma for two hours with adhesion quantified by confocal microscopy measurements of immunofluorescently labeled bovine platelets. Platelet adhesion under pulsating flow is found to exponentially decay with increasing shear rate. Adhesion levels are found to depend upon peak platelet flux and shear rate regardless of rotational waveform. In combination with flow measurements, these results may be useful for predicting regions susceptible to thrombus formation within ventricular assist devices. PMID:24721222

  15. CT evaluation of sigmoid plate dehiscence causing pulsatile tinnitus

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Pengfei; Lv, Han; Dong, Cheng; Wang, Zhenchang [Capital Medical University, Department of Radiology, Beijing Friendship Hospital, Beijing (China); Niu, Yantao; Xian, Junfang [Capital Medical University, Department of Radiology, Beijing Tongren Hospital, Beijing (China)

    2016-01-15

    To evaluate the characteristics of sigmoid plate dehiscence (SPD) causing pulsatile tinnitus (PT) on CT arteriography and venography (CTA + V). Thirty PT patients treated successfully with SPD reconstruction were enrolled. Sixty asymptomatic patients were matched. The location, extent, number of SPD cases and concomitant signs, including venous outflow dominance, transverse sinus stenosis, high jugular bulb, temporal bone pneumatization, height of pituitary gland and pituitary fossa, abnormal mastoid emissary vein, were detected and compared using CTA + V. More than one SPD was found on the symptomatic side in 13/30 PT patients (43.3 %). The upper segment of the sigmoid plate was involved in 29/44 SPDs in the vertical direction (65.9 %); the lateral wall was involved in 38/44 SPDs in the horizontal direction (86.4 %). Singular SPD was detected in 3/60 asymptomatic patients (1.67 ± 0.35 mm{sup 2}), less so in PT patients (7.97 ± 5.17 mm{sup 2}). Compared with the control group, ipsilateral venous outflow dominance, high jugular bulb and bilateral transverse sinus stenosis were more common in the PT group, together with deeper pituitary fossa and flatter pituitary glands. SPD causing PT has characteristic CT findings. It may be generated by vascular or intracranial pressure abnormalities and act as a common key to triggering PT's perception. (orig.)

  16. Observation of the CSF pulsatile flow on MRI, (2)

    International Nuclear Information System (INIS)

    Ohara, Shigeki; Nagai, Hajime; Suzuka, Tomonao; Matsumoto, Takashi; Banno, Tatsuo

    1988-01-01

    In a retrospective study of the MR images of 289 neurosurgical patients, a loss of the signal intensity (the signal-void phenomenon =SVP) of the cerebrospinal fluid in the mesencephalic aqueduct was observed in 77 patients. The CSF in the cranial cavity flows toward the spinal sac in a to-and-fro manner in response to the pulsations of the brain. Because the intracranial compliance is lower than the intraspinal compliance, the systolic expansions and diastolic reductions in the brain volume are buffered by the spinal cavity via this to-and-fro flow of CSF. The SVP reflects the CSF pulsatile flow forced out of the intracranial space into the intraspinal space by the brain's pulsations. Intracranial abnormalities can be divided into two categories according to the craniospinal compliance (CC): normal CC (communicating hydrocephalus) and decreased CC (supratentorial tumor). We may expect those conditions which increase compliance to increase the CSF flow and yield a more prominent SVP. Conversely, conditions which decrease compliance may be expected to decrease the flow and extinguish the SVP. Both the brain's pulsations and the compliance of the craniospinal cavity are closely related to the presence of the SVP in CSF, as revealed by MRI. The SVP in CSF may reflect the pressure-buffering capacity of the cranio-spinal cavity. If further investigation supports our hypothesis, it may be possible to estimate the intracranial pressure noninvasively. (author)

  17. Pulsatile pressure driven rarefied gas flow in long rectangular ducts

    Science.gov (United States)

    Tsimpoukis, Alexandros; Valougeorgis, Dimitris

    2018-04-01

    The pulsatile pressure driven fully developed flow of a rarefied gas through an orthogonal duct is investigated, based on the time-dependent linear Bhatnagar, Gross, and Krook equation, by decomposing the flow into its steady and oscillatory parts. The investigation is focused on the oscillatory part, which is characterized by the gas rarefaction and oscillation parameters, the duct aspect ratio, and the accommodation coefficient. As the oscillation frequency is increased, the amplitude of all macroscopic quantities is decreased, while their phase angle lag is increased reaching the limiting value of π/2. As the gas becomes more rarefied, higher frequencies are needed to trigger this behavior. At small and moderate frequencies, there is a critical degree of gas rarefaction, where a maximum flow rate is obtained. As the duct aspect ratio is decreased and tends to zero, the flow rate and mean wall shear stress amplitudes are increased, while their phase angle lags are slightly affected. The accommodation coefficient has a significant effect on the amplitude and a very weak one on the phase angle of the macroscopic quantities. The computation of the inertia and viscous forces clarifies when the flow consists of only one oscillating viscous region or of two regions, namely, the inviscid piston flow in the core and the oscillating Stokes layer at the wall with the velocity overshooting. Finally, the time average oscillatory pumping power is increased as the oscillation frequency is reduced and its maximum value is one half of the corresponding steady one.

  18. Measurement of pulsatile motion with millisecond resolution by MRI.

    Science.gov (United States)

    Souchon, Rémi; Gennisson, Jean-Luc; Tanter, Mickael; Salomir, Rares; Chapelon, Jean-Yves; Rouvière, Olivier

    2012-06-01

    We investigated a technique based on phase-contrast cine MRI combined with deconvolution of the phase shift waveforms to measure rapidly varying pulsatile motion waveforms. The technique does not require steady-state displacement during motion encoding. Simulations and experiments were performed in porcine liver samples in view of a specific application, namely the observation of transient displacements induced by acoustic radiation force. Simulations illustrate the advantages and shortcomings of the methods. For experimental validation, the waveforms were acquired with an ultrafast ultrasound scanner (Supersonic Imagine Aixplorer), and the rates of decay of the waveforms (relaxation time) were compared. With bipolar motion-encoding gradient of 8.4 ms, the method was able to measure displacement waveforms with a temporal resolution of 1 ms over a time course of 40 ms. Reasonable agreement was found between the rate of decay of the waveforms measured in ultrasound (2.8 ms) and in MRI (2.7-3.3 ms). Copyright © 2011 Wiley-Liss, Inc.

  19. CT evaluation of sigmoid plate dehiscence causing pulsatile tinnitus

    International Nuclear Information System (INIS)

    Zhao, Pengfei; Lv, Han; Dong, Cheng; Wang, Zhenchang; Niu, Yantao; Xian, Junfang

    2016-01-01

    To evaluate the characteristics of sigmoid plate dehiscence (SPD) causing pulsatile tinnitus (PT) on CT arteriography and venography (CTA + V). Thirty PT patients treated successfully with SPD reconstruction were enrolled. Sixty asymptomatic patients were matched. The location, extent, number of SPD cases and concomitant signs, including venous outflow dominance, transverse sinus stenosis, high jugular bulb, temporal bone pneumatization, height of pituitary gland and pituitary fossa, abnormal mastoid emissary vein, were detected and compared using CTA + V. More than one SPD was found on the symptomatic side in 13/30 PT patients (43.3 %). The upper segment of the sigmoid plate was involved in 29/44 SPDs in the vertical direction (65.9 %); the lateral wall was involved in 38/44 SPDs in the horizontal direction (86.4 %). Singular SPD was detected in 3/60 asymptomatic patients (1.67 ± 0.35 mm 2 ), less so in PT patients (7.97 ± 5.17 mm 2 ). Compared with the control group, ipsilateral venous outflow dominance, high jugular bulb and bilateral transverse sinus stenosis were more common in the PT group, together with deeper pituitary fossa and flatter pituitary glands. SPD causing PT has characteristic CT findings. It may be generated by vascular or intracranial pressure abnormalities and act as a common key to triggering PT's perception. (orig.)

  20. DsbA-L prevents obesity-induced inflammation and insulin resistance by suppressing the mtDNA release-activated cGAS-cGAMP-STING pathway.

    Science.gov (United States)

    Bai, Juli; Cervantes, Christopher; Liu, Juan; He, Sijia; Zhou, Haiyan; Zhang, Bilin; Cai, Huan; Yin, Dongqing; Hu, Derong; Li, Zhi; Chen, Hongzhi; Gao, Xiaoli; Wang, Fang; O'Connor, Jason C; Xu, Yong; Liu, Meilian; Dong, Lily Q; Liu, Feng

    2017-11-14

    Chronic inflammation in adipose tissue plays a key role in obesity-induced insulin resistance. However, the mechanisms underlying obesity-induced inflammation remain elusive. Here we show that obesity promotes mtDNA release into the cytosol, where it triggers inflammatory responses by activating the DNA-sensing cGAS-cGAMP-STING pathway. Fat-specific knockout of disulfide-bond A oxidoreductase-like protein (DsbA-L), a chaperone-like protein originally identified in the mitochondrial matrix, impaired mitochondrial function and promoted mtDNA release, leading to activation of the cGAS-cGAMP-STING pathway and inflammatory responses. Conversely, fat-specific overexpression of DsbA-L protected mice against high-fat diet-induced activation of the cGAS-cGAMP-STING pathway and inflammation. Taken together, we identify DsbA-L as a key molecule that maintains mitochondrial integrity. DsbA-L deficiency promotes inflammation and insulin resistance by activating the cGAS-cGAMP-STING pathway. Our study also reveals that, in addition to its well-characterized roles in innate immune surveillance, the cGAS-cGAMP-STING pathway plays an important role in mediating obesity-induced metabolic dysfunction.

  1. Pressure suppression device

    International Nuclear Information System (INIS)

    Mizumachi, Wataru; Fukuda, Akira; Kitaguchi, Hidemi; Shimizu, Toshiaki.

    1976-01-01

    Object: To relieve and absorb impact wave vibrations caused by steam and non-condensed gases releasing into the pressure suppression chamber at the time of an accident. Structure: The reactor container is filled with inert gases. A safety valve attached main steam pipe is provided to permit the excessive steam to escape, the valve being communicated with the pressure suppression chamber through an exhaust pipe. In the pressure suppression chamber, a doughnut-like cylindrical outer wall is filled at its bottom with pool water to condense the high temperature vapor released through the exhaust pipe. A head portion of a vent tube which leads the exhaust pipe is positioned at the top, and a down comer and an exhaust vent tube are locked by means of steady rests. At the bottom is mounted a pressure adsorber device which adsorbs a pressure from the pool water. (Kamimura, M.)

  2. Endotoxin-Induced Inflammation Suppresses the Effect of Melatonin on the Release of LH from the Ovine Pars Tuberalis Explants—Ex Vivo Study

    Directory of Open Access Journals (Sweden)

    Karolina Wojtulewicz

    2017-11-01

    Full Text Available The secretion of the hormone melatonin reliably reflects environmental light conditions. Among numerous actions, in seasonal breeders, melatonin may regulate the secretion of the gonadotropins acting via its corresponding receptors occurring in the Pars Tuberalis (PT. However, it was previously found that the secretory activity of the pituitary may be dependent on the immune status of the animal. Therefore, this study was designed to determine the role of melatonin in the modulation of luteinizing hormone (LH secretion from the PT explants collected from saline- and endotoxin-treated ewes in the follicular phase of the oestrous cycle. Twelve Blackhead ewes were sacrificed 3 h after injection with lipopolysaccharide (LPS; 400 ng/kg or saline, and the PTs were collected. Each PT was cut into 4 explants, which were then divided into 4 groups: I, incubated with ‘pure’ medium 199; II, treated with gonadotropin-releasing hormone (GnRH (100 pg/mL; III, treated with melatonin (10 nmol/mL; and IV, incubated with GnRH and melatonin. Melatonin reduced (p < 0.05 GnRH-induced secretion of LH only in the PT from saline-treated ewes. Explants collected from LPS-treated ewes were characterized by lower (p < 0.05 GnRH-dependent response in LH release. It was also found that inflammation reduced the gene expression of the GnRH receptor and the MT1 melatonin receptors in the PT. Therefore, it was shown that inflammation affects the melatonin action on LH secretion from the PT, which may be one of the mechanisms via which immune/inflammatory challenges disturb reproduction processes in animals.

  3. Cerebrovascular pulsatility in patients with sleep-disordered breathing.

    Science.gov (United States)

    Ramos, Alberto R; Cabral, Digna; Lee, David J; Sacco, Ralph L; Rundek, Tatjana

    2013-05-01

    The aim of our study is to determine the association between the pulsatility index (PI), a surrogate of cerebral small vessel disease and sleep-disordered breathing (SDB). We conducted a transcranial Doppler ultrasound (TCD) study of 19 consecutive patients free of stroke and cardiovascular disease, referred for the evaluation of SDB. TCD was performed by a certified technologist. Subsequent polysomnography was performed according to the practice parameters of the American Academy of Sleep Medicine. We evaluated the association between the apnea-hypopnea index (AHI), the oxygen nadir, the blood flow velocities, and the Gosling PI, for the middle cerebral artery. We performed Spearman's rank correlation and nonparametric regression to evaluate the relationship between AHI, oxygen levels, and the PI. Median age was 48 years (range 37-83), with 52 % male sex (n = 10), and median BMI of 29.9 (range 25-40.4). The median AHI was 16.4 (0.2-69). The median PI was 0.97 (0.72-1.89) cm/s. The PI correlated with the AHI (rho = 0.44; p = 0.004) and with age (rho = 0.57; p = 0.001). Nonparametric regression adjusting for age showed a positive association between the AHI and the PI (standardized estimate = 0.88; p = 0.002). There was no relation between the oxygen nadir and the PI. We observed increased PI in patients with SDB during wakefulness. The PI could potentially be an estimate of cerebral small vessel disease in patients with SDB and hence allow evaluating cerebral hemodynamics during wakefulness with a clinically relevant device.

  4. Pulsatile flow effects on the hemodynamics of intracranial aneurysms.

    Science.gov (United States)

    Le, Trung B; Borazjani, Iman; Sotiropoulos, Fotis

    2010-11-01

    High-resolution numerical simulations are carried out to systematically investigate the effect of the incoming flow waveform on the hemodynamics and wall shear stress patterns of an anatomic sidewall intracranial aneurysm model. Various wave forms are constructed by appropriately scaling a typical human waveform such that the waveform maximum and time-averaged Reynolds numbers, the Womersley number (α), and the pulsatility index (PI) are systematically varied within the human physiologic range. We show that the waveform PI is the key parameter that governs the vortex dynamics across the aneurysm neck and the flow patterns within the dome. At low PI, the flow in the dome is similar to a driven cavity flow and is characterized by a quasi-stationary shear layer that delineates the parent artery flow from the recirculating flow within the dome. At high PI, on the other hand, the flow is dominated by vortex ring formation, transport across the neck, and impingement and breakdown at the distal wall of the aneurysm dome. We further show that the spatial and temporal characteristics of the wall shear stress field on the aneurysm dome are strongly correlated with the vortex dynamics across the neck. We finally argue that the ratio between the characteristic time scale of transport by the mean flow across the neck and the time scale of vortex ring formation can be used to predict for a given sidewall aneurysm model the critical value of the waveform PI for which the hemodynamics will transition from the cavity mode to the vortex ring mode.

  5. Investigation of pulsatile flowfield in healthy thoracic aorta models.

    Science.gov (United States)

    Wen, Chih-Yung; Yang, An-Shik; Tseng, Li-Yu; Chai, Jyh-Wen

    2010-02-01

    Cardiovascular disease is the primary cause of morbidity and mortality in the western world. Complex hemodynamics plays a critical role in the development of aortic dissection and atherosclerosis, as well as many other diseases. Since fundamental fluid mechanics are important for the understanding of the blood flow in the cardiovascular circulatory system of the human body aspects, a joint experimental and numerical study was conducted in this study to determine the distributions of wall shear stress and pressure and oscillatory WSS index, and to examine their correlation with the aortic disorders, especially dissection. Experimentally, the Phase-Contrast Magnetic Resonance Imaging (PC-MRI) method was used to acquire the true geometry of a normal human thoracic aorta, which was readily converted into a transparent thoracic aorta model by the rapid prototyping (RP) technique. The thoracic aorta model was then used in the in vitro experiments and computations. Simulations were performed using the computational fluid dynamic (CFD) code ACE+((R)) to determine flow characteristics of the three-dimensional, pulsatile, incompressible, and Newtonian fluid in the thoracic aorta model. The unsteady boundary conditions at the inlet and the outlet of the aortic flow were specified from the measured flowrate and pressure results during in vitro experiments. For the code validation, the predicted axial velocity reasonably agrees with the PC-MRI experimental data in the oblique sagittal plane of the thoracic aorta model. The thorough analyses of the thoracic aorta flow, WSSs, WSS index (OSI), and wall pressures are presented. The predicted locations of the maxima of WSS and the wall pressure can be then correlated with that of the thoracic aorta dissection, and thereby may lead to a useful biological significance. The numerical results also suggest that the effects of low WSS and high OSI tend to cause wall thickening occurred along the inferior wall of the aortic arch and the

  6. Uric acid association with pulsatile and steady components of central and peripheral blood pressures.

    Science.gov (United States)

    Lepeytre, Fanny; Lavoie, Pierre-Luc; Troyanov, Stéphan; Madore, François; Agharazii, Mohsen; Goupil, Rémi

    2018-03-01

    Whether the cardiovascular risk attributed to elevated uric acid levels may be explained by changes in central and peripheral pulsatile and/or steady blood pressure (BP) components remains controversial. In a cross-sectional analysis of normotensive and untreated hypertensive participants of the CARTaGENE populational cohort, we examined the relationship between uric acid, and both pulsatile and steady components of peripheral and central BP, using sex-stratified linear regressions. Of the 20 004 participants, 10 161 individuals without antihypertensive or uric acid-lowering drugs had valid pulse wave analysis and serum uric acid levels. In multivariate analysis, pulsatile components of BP were not associated with uric acid levels, whereas steady components [mean BP (MBP), peripheral and central DBP] were all associated with higher levels of uric acid levels in women and men (all P uric acid levels but not for MBP-adjusted cSBP. Peripheral and cSBP, which are aggregate measures of pulsatile and steady BP, were also associated with uric acid levels in women (β = 0.063 and 0.072, respectively, both P uric acid levels. Serum uric acid levels appear to be associated with both central and peripheral steady but not pulsatile BP, regardless of sex.

  7. Chronic suppression of testicular function by constant infusion of gonadotropin-releasing hormone agonist and testosterone supplementation in the bonnet monkey (Macaca radiata).

    Science.gov (United States)

    Ravindranath, N; Ramesh, V; Krishnamurthy, H N; Rao, A J; Moudgal, R N

    1992-03-01

    To study the efficacy of long-term buserelin acetate infusion to desensitize pituitary and block testicular function in adult male monkeys (Macaca radiata). Proven fertile male monkeys exhibiting normal testicular function. Each of the control (n = 5) and experimental monkeys (n = 10) received a fresh miniosmotic pump every 21 days, whereas pumps in controls delivered vehicle of experimentals released 50 micrograms buserelin acetate every 24 hours. On day 170 (renewed every 60 days) a silastic capsule containing crystalline testosterone (T) was implanted in the experimental monkeys. At the end of 3 years, treatment was stopped, and recovery of testicular function and fertility monitored. (1) Treatment resulted in marked reduction of nocturnal but not basal serum T; (2) the pituitary remained desensitized to buserelin acetate throughout the 3-year period; (3) animals were largely azoospermic with occasional oligospermia exhibited by two monkeys; and (4) withdrawal of treatment restored testicular function, with 70% of animals regaining fertility. Long-term infertility (but restorable) can be induced in male monkeys by constant infusion of buserelin acetate and T.

  8. Lack of Outer Membrane Protein A Enhances the Release of Outer Membrane Vesicles and Survival of Vibrio cholerae and Suppresses Viability of Acanthamoeba castellanii

    Directory of Open Access Journals (Sweden)

    Soni Priya Valeru

    2014-01-01

    Full Text Available Vibrio cholerae, the causative agent of the diarrhoeal disease cholera, survives in aquatic environments. The bacterium has developed a survival strategy to grow and survive inside Acanthamoeba castellanii. It has been shown that V. cholerae expresses outer membrane proteins as virulence factors playing a role in the adherence to interacted host cells. This study examined the role of outer membrane protein A (OmpA and outer membrane vesicles (OMVs in survival of V. cholerae alone and during its interaction with A. castellanii. The results showed that an OmpA mutant of V. cholerae survived longer than wild-type V. cholerae when cultivated alone. Cocultivation with A. castellanii enhanced the survival of both bacterial strains and OmpA protein exhibited no effect on attachment, engulfment, and survival inside the amoebae. However, cocultivation of the OmpA mutant of V. cholerae decreased the viability of A. castellanii and this bacterial strain released more OMVs than wild-type V. cholerae. Surprisingly, treatment of amoeba cells with OMVs isolated from the OmpA mutant significantly decreased viable counts of the amoeba cells. In conclusion, the results might highlight a regulating rule for OmpA in survival of V. cholerae and OMVs as a potent virulence factor for this bacterium towards eukaryotes in the environment.

  9. On the pulsatile nature of intracranial and spinal CSF-circulation demonstrated by MR imaging

    International Nuclear Information System (INIS)

    Greitz, D.; Franck, A.; Nordell, B.

    1993-01-01

    Cerebrospinal fluid (CSF) flow was studied in 24 healthy volunteers using gated MR phase imaging. The subarachnoid space (SAS) was divided into 5 compartments depending on the magnitude of the pulsatile CSF flows: a high velocity compartment in the area of the brain stem and spinal cord, 2 slow ones at the upper and lower extremes of the SAS, and finally 2 intermediate velocity compartments in between. The main pulsatile spinal flow channel had a meandering pattern. The extraventricular CSF-circulation can be explained by pulsatile CSF flow without the necessity of assuming existence of a net flow. A successive time offset during the cardiac cycle has been found in the fronto-occipital direction of the interplay between the arterial expansion, brain expansion, volume changes of the CSF spaces and of the veins. It is proposed to name this time offset the intracranial ''volume wave'' (VoW). (orig.)

  10. Superior vena cava syndrome after pulsatile bidirectional Glenn shunt procedure: Perioperative implications

    Directory of Open Access Journals (Sweden)

    Neema Praveen

    2009-01-01

    Full Text Available Bidirectional superior cavopulmonary shunt (bidirectional Glenn shunt is generally performed in many congenital cardiac anomalies where complete two ventricle circulations cannot be easily achieved. The advantages of BDG shunt are achieved by partially separating the pulmonary and systemic venous circuits, and include reduced ventricular preload and long-term preservation of myocardium. The benefits of additional pulsatile pulmonary blood flow include the potential growth of pulmonary arteries, possible improvement in arterial oxygen saturation, and possible prevention of development of pulmonary arteriovenous malformations. However, increase in the systemic venous pressure after BDG with additional pulsatile blood flow is known. We describe the peri-operative implications of severe flow reversal in the superior vena cava after pulsatile BDG shunt construction in a child who presented for surgical interruption of the main pulmonary artery.

  11. [Effectiveness and safety of pulsatile GnRH pump therapy on female patients with IHH].

    Science.gov (United States)

    Liu, Zhaoxiang; Mao, Jiangfeng; Wu, Xueyan; Nie, Min; Huang, Bingkun; Xu, Hongli; Wang, Xi; Zheng, Junjie

    2015-11-10

    To investigate the therapeutic effect of pulsatile GnRH (gonadorelin) pump on female patients with idiopathic hypogonadotropic hypogonadism (IHH). In this retrospective study, five female IHH patients were recruited. Patients were treated with pulsatile gonadorelin (10 µg per 90 min) via a pump for at least 12 weeks. Serum gonadotropins and sex steroid levels were measured, and menses were recorded. After one-week treatment, luteinizing hormone (LH) level increased from (2.2 ± 2.0) U/L to (5.4 ± 2.5) U/L (P=0.028), follicle-stimulating hormone(FSH) level increased from (3.7 ± 2.7) U/L to(6.3 ± 1.0) U/L (P=0.162), and estradiol (E2) level increased from (58 ± 13) pmol/L to (260 ± 97) pmol/L (P=0.011). Menstrual bleeding was observed in 4 patients after starting treatment for 35-55 days and two natural pregnancies were reported. No menstrual bleeding was reported in another patient. The frequency of pulsatile GnRH had to be adjusted according to endogenous GnRH secretion during the follicular phase of normal women and regular menses were induced. Pulsatile GnRH is effective in treating female IHH. A constant frequency of pulsatile GnRH is suitable for most of IHH patients. However, for those who failed to produce regular menses, adjusting pulsatile frequency to imitate the physiological rhythm of GnRH may be an alternative option.

  12. Evaluation of hepatic venous pulsatility and portal venous velocity with doppler ultrasonography during the puerperium

    Energy Technology Data Exchange (ETDEWEB)

    Pekindil, Goekhan [Department of Radiology, Trakya University School of Medicine, 22030 Edirne (Turkey); Varol, Fuesun G. [Department of Obstetrics and Gynecology, Trakya University School of Medicine, 22030 Edirne (Turkey); Ali Yuece, M. [Department of Obstetrics and Gynecology, Trakya University School of Medicine, 22030 Edirne (Turkey); Yardim, Turgut [Department of Obstetrics and Gynecology, Trakya University School of Medicine, 22030 Edirne (Turkey)

    1999-03-01

    Objective: The aim of this study is to evaluate pregnancy-induced changes of hepatic venous pulsatility and portal venous velocity in the puerperium and to determine if these changes disappeared by the end of the puerperium. Methods and material: Healthy normal volunteers (90) were examined on the 2nd and 7th days of puerperium and between the 6th and 8th weeks postpartum. Doppler waveform patterns were obtained in the middle hepatic vein and main portal vein. The hepatic venous pulsatility was named as normal, damped or flat. Results: On the 2nd day postpartum, the hepatic vein pulsatility was shown as normal in 8 (26%), damped in 11 (37%) and flat in 11 (37%) cases. On the 7th day postpartum, 15 (50%) cases had normal, 9 (30%) cases had dampened, and 6 (20%) cases had still flat pattern. The majority of the cases (60%) displayed normal hepatic venous pulsatility in the 6th and 8th weeks of puerperium, whereas 23% had still dampened and 17% had flat patterns. There was a trend toward normal pulsatility with increasing puerperal age. The mean portal venous velocity was still higher than the non-pregnant levels and did not showed significant alterations during puerperium. Conclusion: This study emphasised that, since pregnancy-induced alterations in hepatic venous pulsatility and portal venous velocity had not completely returned to normal in most cases until the end of the puerperium, these physiological changes should be considered whenever hepatic and portal systems are interpreted with Doppler sonography during the puerperal period.

  13. Evaluation of hepatic venous pulsatility and portal venous velocity with doppler ultrasonography during the puerperium

    International Nuclear Information System (INIS)

    Pekindil, Goekhan; Varol, Fuesun G.; Ali Yuece, M.; Yardim, Turgut

    1999-01-01

    Objective: The aim of this study is to evaluate pregnancy-induced changes of hepatic venous pulsatility and portal venous velocity in the puerperium and to determine if these changes disappeared by the end of the puerperium. Methods and material: Healthy normal volunteers (90) were examined on the 2nd and 7th days of puerperium and between the 6th and 8th weeks postpartum. Doppler waveform patterns were obtained in the middle hepatic vein and main portal vein. The hepatic venous pulsatility was named as normal, damped or flat. Results: On the 2nd day postpartum, the hepatic vein pulsatility was shown as normal in 8 (26%), damped in 11 (37%) and flat in 11 (37%) cases. On the 7th day postpartum, 15 (50%) cases had normal, 9 (30%) cases had dampened, and 6 (20%) cases had still flat pattern. The majority of the cases (60%) displayed normal hepatic venous pulsatility in the 6th and 8th weeks of puerperium, whereas 23% had still dampened and 17% had flat patterns. There was a trend toward normal pulsatility with increasing puerperal age. The mean portal venous velocity was still higher than the non-pregnant levels and did not showed significant alterations during puerperium. Conclusion: This study emphasised that, since pregnancy-induced alterations in hepatic venous pulsatility and portal venous velocity had not completely returned to normal in most cases until the end of the puerperium, these physiological changes should be considered whenever hepatic and portal systems are interpreted with Doppler sonography during the puerperal period

  14. Non-invasive assessment of pulsatile intracranial pressure with phase-contrast magnetic resonance imaging.

    Directory of Open Access Journals (Sweden)

    Geir Ringstad

    Full Text Available Invasive monitoring of pulsatile intracranial pressure can accurately predict shunt response in patients with idiopathic normal pressure hydrocephalus, but may potentially cause complications such as bleeding and infection. We tested how a proposed surrogate parameter for pulsatile intracranial pressure, the phase-contrast magnetic resonance imaging derived pulse pressure gradient, compared with its invasive counterpart. In 22 patients with suspected idiopathic normal pressure hydrocephalus, preceding invasive intracranial pressure monitoring, and any surgical shunt procedure, we calculated the pulse pressure gradient from phase-contrast magnetic resonance imaging derived cerebrospinal fluid flow velocities obtained at the upper cervical spinal canal using a simplified Navier-Stokes equation. Repeated measurements of the pulse pressure gradient were also undertaken in four healthy controls. Of 17 shunted patients, 16 responded, indicating high proportion of "true" normal pressure hydrocephalus in the patient cohort. However, there was no correlation between the magnetic resonance imaging derived pulse pressure gradient and pulsatile intracranial pressure (R = -.18, P = .43. Pulse pressure gradients were also similar in patients and healthy controls (P = .26, and did not differ between individuals with pulsatile intracranial pressure above or below established thresholds for shunt treatment (P = .97. Assessment of pulse pressure gradient at level C2 was therefore not found feasible to replace invasive monitoring of pulsatile intracranial pressure in selection of patients with idiopathic normal pressure hydrocephalus for surgical shunting. Unlike invasive, overnight monitoring, the pulse pressure gradient from magnetic resonance imaging comprises short-term pressure fluctuations only. Moreover, complexity of cervical cerebrospinal fluid flow and -pulsatility at the upper cervical spinal canal may render the pulse pressure gradient a poor surrogate

  15. Obstructive Hydrocephalus Secondary to Enlarged Virchow-Robin Spaces: A Rare Cause of Pulsatile Tinnitus.

    Science.gov (United States)

    Donaldson, Christopher; Chatha, Gurkirat; Chandra, Ronil V; Goldschlager, Tony

    2017-05-01

    Obstructive hydrocephalus secondary to enlarged Virchow-Robin Spaces (VRS) is a rare entity, with only a few cases reported in the literature. Presenting symptoms vary widely from headaches to dizziness. We report a case of a 31-year-old man who presented with pulsatile tinnitus and magnetic resonance imaging showing obstructive hydrocephalus secondary to tumefactive VRS. After a cerebrospinal fluid diversion procedure in the form of an endoscopic third ventriculostomy, he had almost complete resolution of his symptoms. This is the first case of obstructive hydrocephalus secondary to enlarged VRS, presenting with pulsatile tinnitus. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. The Characteristics of Turbulence in Curved Pipes under Highly Pulsatile Flow Conditions

    Science.gov (United States)

    Kalpakli, A.; Örlü, R.; Tillmark, N.; Alfredsson, P. Henrik

    High speed stereoscopic particle image velocimetry has been employed to provide unique data from a steady and highly pulsatile turbulent flow at the exit of a 90 degree pipe bend. Both the unsteady behaviour of the Dean cells under steady conditions, the so called "swirl switching" phenomenon, as well as the secondary flow under pulsations have been reconstructed through proper orthogonal decomposition. The present data set constitutes - to the authors' knowledge - the first detailed investigation of a turbulent, pulsatile flow through a pipe bend.

  17. Controlled drug release for tissue engineering.

    Science.gov (United States)

    Rambhia, Kunal J; Ma, Peter X

    2015-12-10

    Tissue engineering is often referred to as a three-pronged discipline, with each prong corresponding to 1) a 3D material matrix (scaffold), 2) drugs that act on molecular signaling, and 3) regenerative living cells. Herein we focus on reviewing advances in controlled release of drugs from tissue engineering platforms. This review addresses advances in hydrogels and porous scaffolds that are synthesized from natural materials and synthetic polymers for the purposes of controlled release in tissue engineering. We pay special attention to efforts to reduce the burst release effect and to provide sustained and long-term release. Finally, novel approaches to controlled release are described, including devices that allow for pulsatile and sequential delivery. In addition to recent advances, limitations of current approaches and areas of further research are discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Suppressed Belief

    Directory of Open Access Journals (Sweden)

    Komarine Romdenh-Romluc

    2009-12-01

    Full Text Available Moran’s revised conception of conscious belief requires us to reconceptualise suppressed belief. The work of Merleau-Ponty offers a way to do this. His account of motor-skills allows us to understand suppressed beliefs as pre-reflective ways of dealing with the world.

  19. Pulsatile secretion of thyrotropin during fasting: a decrease of thyrotropin pulse amplitude

    NARCIS (Netherlands)

    Romijn, J. A.; Adriaanse, R.; Brabant, G.; Prank, K.; Endert, E.; Wiersinga, W. M.

    1990-01-01

    The effect of fasting on circadian and pulsatile TSH secretion was investigated in eight healthy subjects (four men and four women in the follicular phase). Each subject was studied twice, once during 24 h with normal food intake and once during the last 24 h of a 60-h fast. Blood was sampled every

  20. INFLUENCE OF PULSATILE FLOW ON THE BEHAVIOR OF HUMAN FIBROBLASTS ADHERED TO GLASS

    NARCIS (Netherlands)

    VANKOOTEN, TG; SCHAKENRAAD, JM; VANDERMEI, HC; BUSSCHER, HJ

    1993-01-01

    In the human body, cells contacting biomaterials surfaces are frequently exposed to pulsatile shear stresses, e.g. blood vessel prostheses. Most studies involving shear, however, try to achieve a steady, pulse-free shear stress in studying cell-biomaterial interactions. In this study, human

  1. Tissue Doppler Imaging in the evaluation of abdominal aortic pulsatility: a useful tool for the neonatologist.

    Science.gov (United States)

    Valerio, Enrico; Grison, Alessandra; Capretta, Anna; Golin, Rosanna; Ferrarese, Paola; Bellettato, Massimo

    2017-03-01

    Sonographic cardiac evaluation of newborns with suspected aortic coarctation (AoC) should tend to demonstrate a good phasic and pulsatile flow and the absence of pressure gradient along a normally conformed aortic arch from the modified left parasternal and suprasternal echocardiographic views; these findings, however, may not necessarily rule out a more distal coarctation in the descending aorta. For this reason, the sonographic exam of newborns with suspected AoC should always include a Doppler evaluation of abdominal aortic blood flow from the subcostal view. Occasionally, however, a clearly pulsatile Doppler flow trace in abdominal aorta may be difficult to obtain due to the bad insonation angle existing between the probe and the vessel. In such suboptimal ultrasonic alignment situation, the use of Tissue Doppler Imaging instead of classic Doppler flow imaging may reveal a preserved aortic pulsatility by sampling the aortic wall motion induced by normal flow. We propose to take advantage of the TDI pattern as a surrogate of a normal pulsatile Doppler flow trace in abdominal aorta when the latter is difficult to obtain due to malalignment with the insonated vessel.

  2. Partial thickness autologus calvarial bone orbitocranioplasty for a sphenorbital encephalocele presenting as pulsatile exophthalmos

    OpenAIRE

    Trivedi, Adarsh; Garg, Amrish Kumar; Hiran, Subodh

    2015-01-01

    Basal encephalocele accounts only 1.5% of all encephaloceles. But Sphenorbital encephalocele is the rarest cause of herniation of brain into orbit leading to pulsatile exphothalmos. Authors presenting a case of sphenorbital encephalocele in a 16 yrs old girl successsfully managed by orbitcranioplasty by partilal thickness autologus calvarial bone graft.

  3. Does Flexible Arterial Tubing Retain More Hemodynamic Energy During Pediatric Pulsatile Extracorporeal Life Support?

    Science.gov (United States)

    Wang, Shigang; Kunselman, Allen R; Ündar, Akif

    2017-01-01

    The objective of this study was to evaluate the hemodynamic performance and energy transmission of flexible arterial tubing as the arterial line in a simulated pediatric pulsatile extracorporeal life support (ECLS) system. The ECLS circuit consisted of a Medos Deltastream DP3 diagonal pump head, Medos Hilite 2400 LT oxygenator, Biomedicus arterial/venous cannula (10 Fr/14 Fr), 3 feet of polyvinyl chloride (PVC) arterial tubing or latex rubber arterial tubing, primed with lactated Ringer's solution and packed red blood cells (hematocrit 40%). Trials were conducted at flow rates of 300 to 1200 mL/min (300 mL/min increments) under nonpulsatile and pulsatile modes at 36°C using either PVC arterial tubing (PVC group) or latex rubber tubing (Latex group). Real-time pressure and flow data were recorded using a custom-based data acquisition system. Mean pressures and energy equivalent pressures (EEP) were the same under nonpulsatile mode between the two groups. Under pulsatile mode, EEPs were significantly great than mean pressure, especially in the Latex group (P tubing retained more hemodynamic energy passing through it under pulsatile mode while mean pressures and pressure drops across the ECLS circuit were similar between PVC and latex rubber arterial tubing. Further studies are warranted to verify our findings. © 2016 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  4. Pulsatile hyperglucagonemia fails to increase hepatic glucose production in normal man

    International Nuclear Information System (INIS)

    Paolisso, G.; Scheen, A.J.; Luyckx, A.S.; Lefebvre, P.J.

    1987-01-01

    To study the metabolic effects of pulsatile glucagon administration, six male volunteers were submitted to a 260-min glucose-controlled glucose intravenous infusion using the Biostator. The endogenous secretion of the pancreatic hormones was inhibited by somatostatin, basal insulin secretion was replaced by a continuous insulin infusion, and glucagon was infused intravenously in two conditions at random: either continuously or intermittently. Blood glucose levels and glucose infusion rate were monitored continuously by the Biostator, and classical methodology using a D-[3- 3 H]glucose infusion allowed the authors to study glucose turnover. While basal plasma glucagon levels were similar in both conditions, they plateaued at 189 +/- 38 pg ml -1 during continuous infusion and varied between 95 and 501 pg x ml -1 during pulsatile infusion. When compared with continuous administration, pulsatile glucagon infusion 1) initially induced a similar increase in endogenous (hepatic) glucose production and blood glucose, 2) did not prevent the so-called evanescent effect of glucagon on blood glucose, and 3) after 3 h tended to reduce rather than increase hepatic glucose production. In conclusion, in vivo pulsatile hyperglucanemia in normal man fails to increase hepatic glucose production

  5. Tolerance to continuous intrathecal baclofen infusion can be reversed by pulsatile bolus infusion

    NARCIS (Netherlands)

    Heetla, H. W.; Staal, M. J.; van Laar, T.

    Study design: Pilot study. Objective: To study the effect of pulsatile bolus infusion of intrathecal baclofen (ITB) on daily ITB dose, in patients showing dose increases, probably due to tolerance. Setting: Department of neurology and neurosurgery, University Medical Center Groningen, the

  6. An in vitro experimental study of flow past aortic valve under varied pulsatile conditions

    Science.gov (United States)

    Zhang, Ruihang; Zhang, Yan

    2017-11-01

    Flow past aortic valve represents a complex fluid-structure interaction phenomenon that involves pulsatile, vortical, and turbulent conditions. The flow characteristics immediately downstream of the valve, such as the variation of pulsatile flow velocity, formation of vortices, distribution of shear stresses, are of particular interest to further elucidate the role of hemodynamics in various aortic diseases. However, the fluid dynamics of a realistic aortic valve is not fully understood. Particularly, it is unclear how the flow fields downstream of the aortic valve would change under varied pulsatile inlet boundary conditions. In this study, an in vitro experiment has been conducted to investigate the flow fields downstream of a silicone aortic valve model within a cardiovascular flow simulator. Phased-locked Particle Image Velocimetry measurements were performed to map the velocity fields and Reynolds normal and shear stresses at different phases in a cardiac cycle. Temporal variations of pressure across the valve model were measured using high frequency transducers. Results have been compared for different pulsatile inlet conditions, including varied frequencies (heart rates), magnitudes (stroke volumes), and cardiac contractile functions (shapes of waveforms).

  7. Pulsatile Lavage of Musculoskeletal Wounds Causes Muscle Necrosis and Dystrophic Calcification in a Rat Model.

    Science.gov (United States)

    Chiaramonti, Alexander M; Robertson, Astor D; Nguyen, Thao P; Jaffe, David E; Hanna, E Lex; Holmes, Robert; Barfield, William R; Fourney, William L; Stains, Joseph P; Pellegrini, Vincent D

    2017-11-01

    Adequate irrigation of open musculoskeletal injuries is considered the standard of care to decrease bacterial load and other contaminants. While the benefit of debris removal compared with the risk of further seeding by high-pressure lavage has been studied, the effects of irrigation on muscle have been infrequently reported. Our aim in the present study was to assess relative damage to muscle by pulsatile lavage compared with bulb-syringe irrigation. In an animal model of heterotopic ossification, 24 Sprague-Dawley rats underwent hindlimb blast amputation via detonation of a submerged explosive, with subsequent through-the-knee surgical amputation proximal to the zone of injury. All wounds were irrigated and underwent primary closure. In 12 of the animals, pulsatile lavage (20 psi [138 kPa]) was used as the irrigation method, and in the other 12 animals, bulb-syringe irrigation was performed. A third group of 6 rats did not undergo the blast procedure but instead underwent surgical incision into the left thigh muscle followed by pulsatile lavage. Serial radiographs of the animals were made to monitor the formation of soft-tissue radiopaque lesions until euthanasia at 6 months. Image-guided muscle biopsies were performed at 8 weeks and 6 months (at euthanasia) on representative animals from each group. Histological analysis was performed with hematoxylin and eosin, alizarin red, and von Kossa staining on interval biopsy and postmortem specimens. All animals managed with pulsatile lavage, with or without blast injury, developed soft-tissue radiopaque lesions, whereas no animal that had bulb-syringe irrigation developed these lesions (p = 0.001). Five of the 12 animals that underwent blast amputation with pulsatile lavage experienced wound complications, whereas no animal in the other 2 groups experienced wound complications (p = 0.014). Radiopaque lesions appeared approximately 10 days postoperatively, increased in density until approximately 16 weeks, then

  8. Enhancement of Arterial Pressure Pulsatility by Controlling Continuous-Flow Left Ventricular Assist Device Flow Rate in Mock Circulatory System.

    Science.gov (United States)

    Bozkurt, Selim; van de Vosse, Frans N; Rutten, Marcel C M

    Continuous-flow left ventricular assist devices (CF-LVADs) generally operate at a constant speed, which reduces pulsatility in the arteries and may lead to complications such as functional changes in the vascular system, gastrointestinal bleeding, or both. The purpose of this study is to increase the arterial pulse pressure and pulsatility by controlling the CF-LVAD flow rate. A MicroMed DeBakey pump was used as the CF-LVAD. A model simulating the flow rate through the aortic valve was used as a reference model to drive the pump. A mock circulation containing two synchronized servomotor-operated piston pumps acting as left and right ventricles was used as a circulatory system. Proportional-integral control was used as the control method. First, the CF-LVAD was operated at a constant speed. With pulsatile-speed CF-LVAD assistance, the pump was driven such that the same mean pump output was generated. Continuous and pulsatile-speed CF-LVAD assistance provided the same mean arterial pressure and flow rate, while the index of pulsatility increased significantly for both arterial pressure and pump flow rate signals under pulsatile speed pump support. This study shows the possibility of improving the pulsatility of CF-LVAD support by regulating pump speed over a cardiac cycle without reducing the overall level of support.

  9. Increasing awareness with recognition of pulsatile tinnitus for nurse practitioners in the primary care setting: A case study.

    Science.gov (United States)

    Vecchiarelli, Kelly; Amar, Arun Paul; Emanuele, Donna

    2017-09-01

    Pulsatile tinnitus is a whooshing sound heard synchronous with the heartbeat. It is an uncommon symptom affecting fewer than 10% of patients with tinnitus. It often goes unrecognized in the primary care setting. Failure to recognize this symptom can result in a missed or delayed diagnosis of a potentially life-threatening condition known as a dural arteriovenous fistula. The purpose of this case study is to provide a structured approach to the identification of pulsatile tinnitus and provide management recommendations. A case study and review of pertinent literature. Pulsatile tinnitus usually has a vascular treatable cause. A comprehensive history and physical examination will alert the nurse practitioner (NP) when pulsatile tinnitus is present. Auscultation in specific areas of the head can detect audible or objective pulsatile tinnitus. Pulsatile tinnitus that is audible to the examiner is an urgent medical condition requiring immediate consultation and referral. Knowledge of pulsatile tinnitus and awareness of this often treatable condition directs the NP to perform a detailed assessment when patients present with tinnitus, directs appropriate referral for care and treatment, and can reduce the risk of delayed or missed diagnosis. ©2017 American Association of Nurse Practitioners.

  10. Is the use of low-pressure pulsatile lavage for pressure ulcer management associated with environmental contamination with Acinetobacter baumannii?

    Science.gov (United States)

    Ho, Chester H; Johnson, Tova; Miklacic, Joan; Donskey, Curtis J

    2009-10-01

    Ho CH, Johnson T, Miklacic J, Donskey CJ. Is the use of low-pressure pulsatile lavage for pressure ulcer management associated with environmental contamination with Acinetobacter baumannii? To determine the extent of environmental contamination associated with low-pressure pulsatile lavage of stage III or IV pressure ulcers in patients with spinal cord injury (SCI) when routine infection control precautions are used for wounds colonized or infected with Acinetobacter baumannii. Prospective investigation in which pressure ulcer cultures and environmental cultures were obtained before and after low-pressure pulsatile lavage treatment, and before and after regular dressing changes. Environmental cultures included the patient's bedrail and settle plates placed 0.6, 1.5, and 2.4m from the wound to assess airborne spread of A. baumannii. SCI inpatient unit in a Department of Veterans Affairs Medical Center. Inpatients (N=15) with SCI receiving daily low-pressure pulsatile lavage treatment for stage III or IV pressure ulcers with standard dressing change, as well as regular dressing changes without low-pressure pulsatile lavage at other times of the day. Standard, regular dressing changes and dressing changes with low-pressure pulsatile lavage. Comparison of frequency of environmental contamination with A. baumannii associated with low-pressure pulsatile lavage versus regular dressing changes. Of the 15 SCI inpatients meeting inclusion criteria, 9 (60%) grew A. baumannii from their wounds. Of the 9 patients with wound cultures positive for A. baumannii, only 1 (11%) had environmental contamination with this organism after performance of low-pressure pulsatile lavage, and the same patient had environmental contamination after a standard dressing change. The antibiotic susceptibility patterns of the wound and environmental A. baumannii isolates were identical. Low-pressure pulsatile lavage using the infection control methods described is not associated with an increased

  11. Effects of acute aerobic exercise on arterial stiffness and cerebrovascular pulsatility in adults with and without hypertension.

    Science.gov (United States)

    Lefferts, Wesley K; DeBlois, Jacob P; Receno, Candace N; Barreira, Tiago V; Brutsaert, Tom D; Carhart, Robert L; Heffernan, Kevin S

    2018-04-19

    Stiffer central arteries, as seen in hypertension (HTN), foster transmission of pulsatile hemodynamics into fragile cerebral vessels. Aerobic exercise is recommended for adults with HTN, but its effects on arterial stiffness and pulsatility in this group are unclear. This study sought to investigate the effect of acute aerobic exercise on arterial stiffness and cerebrovascular pulsatility in 30 adults with treated HTN and 30 age, sex, and BMI-matched adults without HTN (56 ± 6 years, BMI 28.2 ± 2.9 kg/m; 28 women). Patients underwent hemodynamic measures before/after 30-min cycling (≈55% peak oxygen consumption). Aortic stiffness was measured using carotid-femoral pulse wave velocity, and carotid artery stiffness was assessed with β-stiffness via ultrasound. Aortic/carotid pulse pressure (aortic via radial generalized transfer function) was measured by tonometry and calibrated to brachial mean pressure and diastolic pressure. Carotid/middle cerebral artery (MCA) blood velocity pulsatility indices were measured using Doppler. Carotid wave intensity analysis was used to derive forward wave intensity (W1). Exercise impacted hemodynamics similarly in HTN compared to no-HTN. Carotid-femoral pulse wave velocity, MCA pulsatility index, carotid pulsatility index, and W1 increased similarly after exercise in both groups (P < 0.05). Carotid pulse pressure and β-stiffness were unaltered after exercise. Postexercise changes in W1 were positively associated with carotid pulsatility index, which was further associated with MCA pulsatility index. These data suggest adults with treated HTN experience similar increases in aortic stiffness and cerebrovascular hemodynamic pulsatility during early recovery from acute aerobic exercise as their counterparts without HTN.

  12. Sigmoid Sinus Diverticulum, Dehiscence, and Venous Sinus Stenosis: Potential Causes of Pulsatile Tinnitus in Patients with Idiopathic Intracranial Hypertension?

    Science.gov (United States)

    Lansley, J A; Tucker, W; Eriksen, M R; Riordan-Eva, P; Connor, S E J

    2017-09-01

    Pulsatile tinnitus is experienced by most patients with idiopathic intracranial hypertension. The pathophysiology remains uncertain; however, transverse sinus stenosis and sigmoid sinus diverticulum/dehiscence have been proposed as potential etiologies. We aimed to determine whether the prevalence of transverse sinus stenosis and sigmoid sinus diverticulum/dehiscence was increased in patients with idiopathic intracranial hypertension and pulsatile tinnitus relative to those without pulsatile tinnitus and a control group. CT vascular studies of patients with idiopathic intracranial hypertension with pulsatile tinnitus ( n = 42), without pulsatile tinnitus ( n = 37), and controls ( n = 75) were independently reviewed for the presence of severe transverse sinus stenosis and sigmoid sinus diverticulum/dehiscence according to published criteria. The prevalence of transverse sinus stenosis and sigmoid sinus diverticulum/dehiscence in patients with idiopathic intracranial hypertension with pulsatile tinnitus was compared with that in the nonpulsatile tinnitus idiopathic intracranial hypertension group and the control group. Further comparisons included differing degrees of transverse sinus stenosis (50% and 75%), laterality of transverse sinus stenosis/sigmoid sinus diverticulum/dehiscence, and ipsilateral transverse sinus stenosis combined with sigmoid sinus diverticulum/dehiscence. Severe bilateral transverse sinus stenoses were more frequent in patients with idiopathic intracranial hypertension than in controls ( P tinnitus within the idiopathic intracranial hypertension group. Sigmoid sinus dehiscence (right- or left-sided) was also more common in patients with idiopathic intracranial hypertension compared with controls ( P = .01), but there was no significant association with pulsatile tinnitus within the idiopathic intracranial hypertension group. While our data corroborate previous studies demonstrating increased prevalence of sigmoid sinus diverticulum

  13. Low-Dose Pulsatile Interleukin-6 As a Treatment Option for Diabetic Peripheral Neuropathy

    Directory of Open Access Journals (Sweden)

    Gautam Ghatnekar

    2017-05-01

    Full Text Available Diabetic peripheral neuropathy (DPN remains one of the most common and serious complications of diabetes. Currently, pharmacological agents are limited to treating the pain associated with DPN, and do not address the underlying pathological mechanisms driving nerve damage, thus leaving a significant unmet medical need. Interestingly, research conducted using exercise as a treatment for DPN has revealed interleukin-6 (IL-6 signaling to be associated with many positive benefits such as enhanced blood flow and lipid metabolism, decreased chronic inflammation, and peripheral nerve fiber regeneration. IL-6, once known solely as a pro-inflammatory cytokine, is now understood to signal as a multifunctional cytokine, capable of eliciting both pro- and anti-inflammatory responses in a context-dependent fashion. IL-6 released from muscle in response to exercise signals as a myokine and as such has a unique kinetic profile, whereby levels are transiently elevated up to 100-fold and return to baseline levels within 4 h. Importantly, this kinetic profile is in stark contrast to long-term IL-6 elevation that is associated with pro-inflammatory states. Given exercise induces IL-6 myokine signaling, and exercise has been shown to elicit numerous beneficial effects for the treatment of DPN, a causal link has been suggested. Here, we discuss both the clinical and preclinical literature related to the application of IL-6 as a treatment strategy for DPN. In addition, we discuss how IL-6 may directly modulate Schwann and nerve cells to explore a mechanistic understanding of how this treatment elicits a neuroprotective and/or regenerative response. Collectively, studies suggest that IL-6, when administered in a low-dose pulsatile strategy to mimic the body’s natural response to exercise, may prove to be an effective treatment for the protection and/or restoration of peripheral nerve function in DPN. This review highlights the studies supporting this assertion and

  14. A Three-Pulse Release Tablet for Amoxicillin: Preparation, Pharmacokinetic Study and Physiologically Based Pharmacokinetic Modeling.

    Science.gov (United States)

    Li, Jin; Chai, Hongyu; Li, Yang; Chai, Xuyu; Zhao, Yan; Zhao, Yunfan; Tao, Tao; Xiang, Xiaoqiang

    2016-01-01

    Amoxicillin is a commonly used antibiotic which has a short half-life in human. The frequent administration of amoxicillin is often required to keep the plasma drug level in an effective range. The short dosing interval of amoxicillin could also cause some side effects and drug resistance, and impair its therapeutic efficacy and patients' compliance. Therefore, a three-pulse release tablet of amoxicillin is desired to generate sustained release in vivo, and thus to avoid the above mentioned disadvantages. The pulsatile release tablet consists of three pulsatile components: one immediate-release granule and two delayed release pellets, all containing amoxicillin. The preparation of a pulsatile release tablet of amoxicillin mainly includes wet granulation craft, extrusion/spheronization craft, pellet coating craft, mixing craft, tablet compression craft and film coating craft. Box-Behnken design, Scanning Electron Microscope and in vitro drug release test were used to help the optimization of formulations. A crossover pharmacokinetic study was performed to compare the pharmacokinetic profile of our in-house pulsatile tablet with that of commercial immediate release tablet. The pharmacokinetic profile of this pulse formulation was simulated by physiologically based pharmacokinetic (PBPK) model with the help of Simcyp®. Single factor experiments identify four important factors of the formulation, namely, coating weight of Eudragit L30 D-55 (X1), coating weight of AQOAT AS-HF (X2), the extrusion screen aperture (X3) and compression forces (X4). The interrelations of the four factors were uncovered by a Box-Behnken design to help to determine the optimal formulation. The immediate-release granule, two delayed release pellets, together with other excipients, namely, Avicel PH 102, colloidal silicon dioxide, polyplasdone and magnesium stearate were mixed, and compressed into tablets, which was subsequently coated with Opadry® film to produce pulsatile tablet of

  15. Estrogen receptor beta and 2-arachydonoylglycerol mediate the suppressive effects of estradiol on frequency of postsynaptic currents in gonadotropin-releasing hormone neurons of metestrous mice: an acute slice electrophysiological study

    Directory of Open Access Journals (Sweden)

    Flóra eBálint

    2016-03-01

    Full Text Available Gonadotropin-releasing hormone (GnRH neurons are controlled by 17β-estradiol (E2 contributing to the steroid feedback regulation of the reproductive axis. In rodents, E2 exerts a negative feedback effect upon GnRH neurons throughout the estrus-diestrus phase of the ovarian cycle. The present study was undertaken to reveal the role of estrogen receptor subtypes in the mediation of the E2 signal and elucidate the downstream molecular machinery of suppression. The effect of E2 administration at low physiological concentration (10 pM on GnRH neurons in acute brain slices obtained from metestrous GnRH-GFP mice was studied under paradigms of blocking or activating estrogen receptor subtypes and interfering with retrograde 2-arachydonoylglycerol (2-AG signaling. Whole-cell patch clamp recordings revealed that E2 significantly diminished the frequency of spontaneous postsynaptic currents (sPSCs in GnRH neurons (49. 62±7.6% which effect was abolished by application of the ERα/β blocker Faslodex (1 µM. Pretreatment of the brain slices with cannabinoid receptor type 1 (CB1 inverse agonist AM251 (1 µM and intracellularly applied endocannabinoid synthesis blocker THL (10 µM significantly attenuated the effect of E2 on the sPSCs. E2 remained effective in the presence of TTX indicating a direct action of E2 on GnRH cells. The ERβ specific agonist DPN (10 pM also significantly decreased the frequency of miniature postsynaptic currents (mPSCs in GnRH neurons. In addition, the suppressive effect of E2 was completely blocked by the selective ERβ antagonist PHTPP (1 µM indicating that ERβ is required for the observed rapid effect of the E2. In contrast, the ERα agonist PPT (10 pM or the membrane-associated G protein-coupled estrogen receptor (GPR30 agonist G1 (10 pM had no significant effect on the frequency of mPSCs in these neurons. AM251 and THL significantly abolished the effect of E2 whereas AM251 eliminated the action of DPN on the mPSCs. These

  16. Pulsatile dry cupping in chronic low back pain - a randomized three-armed controlled clinical trial.

    Science.gov (United States)

    Teut, M; Ullmann, A; Ortiz, M; Rotter, G; Binting, S; Cree, M; Lotz, F; Roll, S; Brinkhaus, B

    2018-04-02

    We aimed to investigate the effectiveness of two different forms of dry pulsatile cupping in patients with chronic low back pain (cLBP) compared to medication on demand only in a three-armed randomized trial. 110 cLBP patients were randomized to regular pulsatile cupping with 8 treatments plus paracetamol on demand (n = 37), minimal cupping with 8 treatments plus paracetamol on demand (n = 36) or the control group with paracetamol on demand only (n = 37). Primary outcome was the pain intensity on a visual analogue scale (VAS, 0-100 mm) after 4 weeks, secondary outcome parameter included VAS pain intensity after 12 weeks, back function as measured with the 'Funktionsfragebogen Hannover Rücken' (FFbH-R) and health related quality of life questionnaire Short form 36 (SF-36) after 4 and 12 weeks. The mean baseline-adjusted VAS after 4 weeks was 34.9 mm (95% CI: 28.7; 41.2) for pulsatile cupping, 40.4 (34.2; 46.7) for minimal cupping and 56.1 (49.8; 62.4) for control group, resulting in statistically significant differences between pulsatile cupping vs. control (21.2 (12.2; 30.1); p back function after 4 weeks, but not after 12 weeks (- 5.4 (- 11.7;0.8); p = 0.088), pulsatile cupping also showed better improvements on SF-36 physical component scale compared to control at 4 and 12 weeks (- 5.6 (- 9.3;-2.0); p = 0.003; - 6.1 (- 9.9;-2.4); p = 0.002). For back function and quality of life minimal cupping group was not statistically different to control after 4 and 12 weeks. Paracetamol intake did not differ between the groups (cupping vs. control (7.3 (- 0.4;15.0); p = 0.063); minimal cupping vs. control (6.3 (- 2.0;14.5); p = 0.133). Both forms of cupping were effective in cLBP without showing significant differences in direct comparison after four weeks, only pulsatile cupping showed effects compared to control after 12 weeks. The study was registered at ClinicalTrials.gov (identifier: NCT02090686 ).

  17. 2',3-dihydroxy-5-methoxybiphenyl suppresses fMLP-induced superoxide anion production and cathepsin G release by targeting the β-subunit of G-protein in human neutrophils.

    Science.gov (United States)

    Liao, Hsiang-Ruei; Chen, Ih-Sheng; Liu, Fu-Chao; Lin, Shinn-Zhi; Tseng, Ching-Ping

    2018-06-15

    This study investigates the effect and the underlying mechanism of 2',3-dihydroxy-5-methoxybiphenyl (RIR-2), a lignan extracted from the roots of Rhaphiolepis indica (L.) Lindl. ex Ker var. tashiroi Hayata ex Matsum. & Hayata (Rosaceae), on N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP)-induced respiratory burst and cathepsin G in human neutrophils. Signaling pathways regulated by RIR-2 which modulated fMLP-induced respiratory burst were evaluated by an interaction between β subunit of G-protein (Gβ) with downstream signaling induced by fMLP and by immunoblotting analysis of the downstream targets of Gβ-protein. RIR-2 inhibited fMLP-induced superoxide anion production (IC 50 :2.57 ± 0.22 μM), cathepsin G release (IC 50 :18.72 ± 3.76 μM) and migration in a concentration dependent manner. RIR-2 specifically suppresses fMLP-induced Src family kinases phosphorylation by inhibiting the interaction between Gβ-protein with Src kinases without inhibiting Src kinases activities, therefore, RIR-2 attenuated the downstream targets of Src kinase, such as phosphorylation of Raf/ERK, AKT, P38, PLCγ2, PKC and translocation Tec, p47 ph ° x and P40 ph ° x from the cytosol to the inner leaflet of the plasma membrane. Furthermore, RIR-2 attenuated fMLP-induced intracellular calcium mobilization by inhibiting the interaction between Gβ-protein with PLCβ2. RIR-2 was not a competitive or allosteric antagonist of fMLP. On the contrary, phorbol 12-myristate 13-acetate (PMA)-induced phosphorylation of Src, AKT, P38, PKC and membrane localization of p47 ph ° x and P40 ph ° x remained unaffected. RIR-2 specifically modulates fMLP-mediated neutrophil superoxide anion production and cathepsin G release by inhibiting the interaction between Gβ-protein with downstream signaling which subsequently interferes with the activation of intracellular calcium, PLCγ2, AKT, p38, PKC, ERK, p47 ph ° x and p40 phox . Copyright © 2018 Elsevier B.V. All rights reserved.

  18. Interocular suppression

    Science.gov (United States)

    Tuna, Ana Rita; Almeida Neves Carrega, Filipa; Nunes, Amélia Fernandes

    2017-08-01

    The objective of this work is to quantify the suppressive imbalance, based on the manipulation of ocular luminance, between a group of subjects with normal binocular vision and a group of subjects with amblyopia. The result reveals that there are statistically significant differences in interocular dominance between two groups, evidencing a greater suppressive imbalance in amblyopic subjects. The technique used, proved to be a simple, easy to apply and economic method, for quantified ocular dominance. It is presented as a technique with the potential to accompany subjects with a marked dominance in one of the eyes that makes fusion difficult.

  19. Precise position control of a helical magnetic robot in pulsatile flow using the rotating frequency of the external magnetic field

    Directory of Open Access Journals (Sweden)

    Jongyul Kim

    2017-05-01

    Full Text Available We propose a position control method for a helical magnetic robot (HMR that uses the rotating frequency of the external rotating magnetic field (ERMF to minimize the position fluctuation of the HMR caused by pulsatile flow in human blood vessels. We prototyped the HMR and conducted several experiments in pseudo blood vessel environments with a peristaltic pump. We experimentally obtained the relation between the flow rate and the rotating frequency of the ERMF required to make the HMR stationary in a given pulsatile flow. Then we approximated the pulsatile flow by Fourier series and applied the required ERMF rotating frequency to the HMR in real time. Our proposed position control method drastically reduced the position fluctuation of the HMR under pulsatile flow.

  20. Suppression of the hypothalamic-pituitary-gonadal axis by TAK-385 (relugolix), a novel, investigational, orally active, small molecule gonadotropin-releasing hormone (GnRH) antagonist: studies in human GnRH receptor knock-in mice.

    Science.gov (United States)

    Nakata, Daisuke; Masaki, Tsuneo; Tanaka, Akira; Yoshimatsu, Mie; Akinaga, Yumiko; Asada, Mari; Sasada, Reiko; Takeyama, Michiyasu; Miwa, Kazuhiro; Watanabe, Tatsuya; Kusaka, Masami

    2014-01-15

    TAK-385 (relugolix) is a novel, non-peptide, orally active gonadotropin-releasing hormone (GnRH) antagonist, which builds on previous work with non-peptide GnRH antagonist TAK-013. TAK-385 possesses higher affinity and more potent antagonistic activity for human and monkey GnRH receptors compared with TAK-013. Both TAK-385 and TAK-013 have low affinity for the rat GnRH receptor, making them difficult to evaluate in rodent models. Here we report the human GnRH receptor knock-in mouse as a humanized model to investigate pharmacological properties of these compounds on gonadal function. Twice-daily oral administration of TAK-013 (10mg/kg) for 4 weeks decreased the weights of testes and ventral prostate in male knock-in mice but not in male wild-type mice, demonstrating the validity of this model to evaluate antagonists for the human GnRH receptor. The same dose of TAK-385 also reduced the prostate weight to castrate levels in male knock-in mice. In female knock-in mice, twice-daily oral administration of TAK-385 (100mg/kg) induced constant diestrous phases within the first week, decreased the uterus weight to ovariectomized levels and downregulated GnRH receptor mRNA in the pituitary after 4 weeks. Gonadal function of TAK-385-treated knock-in mice began to recover after 5 days and almost completely recovered within 14 days after drug withdrawal in both sexes. Our findings demonstrate that TAK-385 acts as an antagonist for human GnRH receptor in vivo and daily oral administration potently, continuously and reversibly suppresses the hypothalamic-pituitary-gonadal axis. TAK-385 may provide useful therapeutic interventions in hormone-dependent diseases including endometriosis, uterine fibroids and prostate cancer. Copyright © 2013 Elsevier B.V. All rights reserved.

  1. Pulsatile turbulent flow through pipe bends at high Dean and Womersley numbers

    Science.gov (United States)

    Kalpakli, Athanasia; Örlü, Ramis; Tillmark, Nils; Alfredsson, P. Henrik

    2011-12-01

    Turbulent pulsatile flows through pipe bends are prevalent in internal combustion engine components which consist of bent pipe sections and branching conduits. Nonetheless, most of the studies related to pulsatile flows in pipe bends focus on incompressible, low Womersley and low Dean number flows, primarily because they aim in modeling blood flow, while internal combustion engine related flows have mainly been addressed in terms of integral quantities and consist of single point measurements. The present study aims at bridging the gap between these two fields by means of time-resolved stereoscopic particle image velocimetry measurements in a pipe bend with conditions that are close to those encountered in exhaust manifolds. The time/phase-resolved three-dimensional cross-sectional flow-field 3 pipe diameters downstream the pipe bend is captured and the interplay between different secondary motions throughout a pulse cycle is discussed.

  2. Pulsatile turbulent flow through pipe bends at high Dean and Womersley numbers

    International Nuclear Information System (INIS)

    Kalpakli, Athanasia; Örlü, Ramis; Tillmark, Nils; Alfredsson, P Henrik

    2011-01-01

    Turbulent pulsatile flows through pipe bends are prevalent in internal combustion engine components which consist of bent pipe sections and branching conduits. Nonetheless, most of the studies related to pulsatile flows in pipe bends focus on incompressible, low Womersley and low Dean number flows, primarily because they aim in modeling blood flow, while internal combustion engine related flows have mainly been addressed in terms of integral quantities and consist of single point measurements. The present study aims at bridging the gap between these two fields by means of time-resolved stereoscopic particle image velocimetry measurements in a pipe bend with conditions that are close to those encountered in exhaust manifolds. The time/phase-resolved three-dimensional cross-sectional flow-field 3 pipe diameters downstream the pipe bend is captured and the interplay between different secondary motions throughout a pulse cycle is discussed.

  3. Feasibility Study of Ex Ovo Chick Chorioallantoic Artery Model for Investigating Pulsatile Variation of Arterial Geometry.

    Directory of Open Access Journals (Sweden)

    Kweon-Ho Nam

    Full Text Available Despite considerable research efforts on the relationship between arterial geometry and cardiovascular pathology, information is lacking on the pulsatile geometrical variation caused by arterial distensibility and cardiomotility because of the lack of suitable in vivo experimental models and the methodological difficulties in examining the arterial dynamics. We aimed to investigate the feasibility of using a chick embryo system as an experimental model for basic research on the pulsatile variation of arterial geometry. Optical microscope video images of various arterial shapes in chick chorioallantoic circulation were recorded from different locations and different embryo samples. The high optical transparency of the chorioallantoic membrane (CAM allowed clear observation of tiny vessels and their movements. Systolic and diastolic changes in arterial geometry were visualized by detecting the wall boundaries from binary images. Several to hundreds of microns of wall displacement variations were recognized during a pulsatile cycle. The spatial maps of the wall motion harmonics and magnitude ratio of harmonic components were obtained by analyzing the temporal brightness variation at each pixel in sequential grayscale images using spectral analysis techniques. The local variations in the spectral characteristics of the arterial wall motion were reflected well in the analysis results. In addition, mapping the phase angle of the fundamental frequency identified the regional variations in the wall motion directivity and phase shift. Regional variations in wall motion phase angle and fundamental-to-second harmonic ratio were remarkable near the bifurcation area. In summary, wall motion in various arterial geometry including straight, curved and bifurcated shapes was well observed in the CAM artery model, and their local and cyclic variations could be characterized by Fourier and wavelet transforms of the acquired video images. The CAM artery model with

  4. Augmentative effect of pulsatility on the wall shear stress in tube flow.

    Science.gov (United States)

    Nakata, M; Tatsumi, E; Tsukiya, T; Taenaka, Y; Nishimura, T; Nishinaka, T; Takano, H; Masuzawa, T; Ohba, K

    1999-08-01

    Wall shear stress (WSS) has been considered to play an important role in the physiological and metabolic functions of the vascular endothelial cells. We investigated the effects of the pulse rate and the maximum flow rate on the WSS to clarify the influence of pulsatility. Water was perfused in a 1/2 inch transparent straight cylinder with a nonpulsatile centrifugal pump and a pulsatile pneumatic ventricular assist device (VAD). In nonpulsatile flow (NF), the flow rate was changed 1 to 6 L/min by 1 L/min increments to obtain standard values of WSS at each flow rate. In pulsatile flow (PF), the pulse rate was controlled at 40, 60, and 80 bpm, and the maximum flow rate was varied from 3.3 to 12.0 L/min while the mean flow rate was kept at 3 L/min. The WSS was estimated from the velocity profile at measuring points using the laser illuminated fluorescence method. In NF, the WSS was 12.0 dyne/cm2 at 3 L/min and 33.0 dyne/cm2 at 6 L/min. In PF, the pulse rate change with the same mean, and the maximum flow rate did not affect WSS. On the other hand, the increase in the maximum flow rate at the constant mean flow rate of 3 L/min augmented the mean WSS from 13.1 to 32.9 dyne/cm2. We concluded that the maximum flow rate exerted a substantial augmentative effect on WSS, and the maximum flow rate was a dominant factor of pulsatility in this effect.

  5. Renal artery pulsatility index and renal volume: Normal fetuses versus growth-retarded fetuses

    International Nuclear Information System (INIS)

    Lee, Kyung Soon; Woo, Bock Hi

    2001-01-01

    To evaluate the blood flow velocity waveform of the renal artery and renal volume of growth-retarded fetuses and to compare them with those of normal fetuses. Pulsatility index of the renal artery and renal volume measured by three-dimensional ultrasonography were obtained from seventy eight normal fetuses at the gestational age from twenty five to thirty nine weeks and eighteen intrauterine growth retarded fetuses whose weight was below ten percentile at birth. We studied changes of the pulsatility index of the renal artery and renal volume according to the gestational age and compared with those of growth-retarded fetuses. Pulsatility index (PI) of the fetal renal artery decreased throughout the gestational period (r=0.703, p<0.0001). In growth-retarded fetuses, despite of abnormal doppler velocity waveform of the middle cerebral artery, which was showing fetal hypoxia, the renal PI was not increased significantly. The fetal renal volume increased throughout the gestational period (r=0.834, p<0.0001) whereas in growth-retarded fetuses, all renal volume was below fifth percentile of normal fetuses. In growth-retarded fetuses, fetal renal volume was decreased significantly without change of the renal vascular flow. Therefore, the fetal renal volume measured by three-dimensional ultrasonography may be a helpful parameter in the diagnosis of growth-retarded fetuses.

  6. An intriguing design concept to enhance the pulsatile fatigue life of self-expanding stents.

    Science.gov (United States)

    Hsiao, Hao-Ming; Yin, Ming-Ting

    2014-02-01

    Intravascular stenting has emerged as the primary treatment for vascular diseases and has received great attention from the medical community since its introduction two decades ago. The endovascular self-expanding stent is used to treat peripheral artery diseases; however, once implanted, these stents suffer from various cyclic motions caused by pulsatile blood pressure and daily activities. Due to this challenging environment, fatigue performance has become a critical issue for stent design. In this paper, a simple yet intriguing concept of stent design aimed at enhancing pulsatile fatigue life is investigated. The concept of this design is to shift the highly concentrated stresses/strains away from the crown and re-distribute them along the stress-free bar arm by tapering its strut width. Finite element models were developed to evaluate the mechanical integrity and pulsatile fatigue resistance of the stent to various loading conditions. Results show that the fatigue safety factor jumped to 2.5-3.0 times that of the standard stent with constant strut width. This is astonishing considering that the stent profile and scaffolding were not compromised. The findings of this paper provide an excellent approach to the optimization of future stent design to greatly improve stent fatigue performance.

  7. A durability study of a paracorporeal pulsatile electro-mechanical pneumatic biventricular assist device.

    Science.gov (United States)

    Choi, Hyuk; Lee, Heung-Man; Nam, Kyoung Won; Choi, Jaesoon; Lee, Jung-Joo; Kim, Ho Chul; Song, Seung Joon; Ahn, Chi Bum; Son, Ho Sung; Lim, Choon Hak; Son, Kuk Hui; Park, Yong Doo; Jeong, Gi Seok; Sun, Kyung

    2011-06-01

    In 2002, the paracorporeal pulsatile electro-mechanical pneumatic ventricular assist device (VAD) began to be developed by the Korea Artificial Organ Center at Korea University under a Health & Medical Technology Research and Development program which finished in 2008. In vitro durability testing was conducted on the paracorporeal pulsatile pneumatic VAD to determine device durability and to evaluate device failures. The 1- and 2-year reliability of the paracorporeal pulsatile pneumatic VAD was shown to be 91.2% and 54.9%, respectively, with an 80% confidence level. Failure modes were analyzed using fault tree analysis, with customized software continuously acquiring data during the test period. After this period, 21 in vivo animal tests were done, with 14 cases of left atrium to left ventricle (LV) inflow cannulation (36Fr)/outflow grafting to descending aorta, and seven cases of apex cannulation of LV to descending aorta (12 mm). The longest postoperative day (182 days) in Korea was recently recorded in in vivo animal testing (bovine, 90 kg, male, 3.5-4.0 L/min flow rate, and 55 bpm). © 2011, Copyright the Authors. Artificial Organs © 2011, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  8. Generating pulsatility by pump speed modulation with continuous-flow total artificial heart in awake calves.

    Science.gov (United States)

    Fukamachi, Kiyotaka; Karimov, Jamshid H; Sunagawa, Gengo; Horvath, David J; Byram, Nicole; Kuban, Barry D; Dessoffy, Raymond; Sale, Shiva; Golding, Leonard A R; Moazami, Nader

    2017-12-01

    The purpose of this study was to evaluate the effects of sinusoidal pump speed modulation of the Cleveland Clinic continuous-flow total artificial heart (CFTAH) on hemodynamics and pump flow in an awake chronic calf model. The sinusoidal pump speed modulations, performed on the day of elective sacrifice, were set at ±15 and ± 25% of mean pump speed at 80 bpm in four awake calves with a CFTAH. The systemic and pulmonary arterial pulse pressures increased to 12.0 and 12.3 mmHg (±15% modulation) and to 15.9 and 15.7 mmHg (±25% modulation), respectively. The pulsatility index and surplus hemodynamic energy significantly increased, respectively, to 1.05 and 1346 ergs/cm at ±15% speed modulation and to 1.51 and 3381 ergs/cm at ±25% speed modulation. This study showed that it is feasible to generate pressure pulsatility with pump speed modulation; the platform is suitable for evaluating the physiologic impact of pulsatility and allows determination of the best speed modulations in terms of magnitude, frequency, and profiles.

  9. Renal artery pulsatility index and renal volume: Normal fetuses versus growth-retarded fetuses

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyung Soon; Woo, Bock Hi [Ewha Womans University College of Medicine, Seoul (Korea, Republic of)

    2001-06-15

    To evaluate the blood flow velocity waveform of the renal artery and renal volume of growth-retarded fetuses and to compare them with those of normal fetuses. Pulsatility index of the renal artery and renal volume measured by three-dimensional ultrasonography were obtained from seventy eight normal fetuses at the gestational age from twenty five to thirty nine weeks and eighteen intrauterine growth retarded fetuses whose weight was below ten percentile at birth. We studied changes of the pulsatility index of the renal artery and renal volume according to the gestational age and compared with those of growth-retarded fetuses. Pulsatility index (PI) of the fetal renal artery decreased throughout the gestational period (r=0.703, p<0.0001). In growth-retarded fetuses, despite of abnormal doppler velocity waveform of the middle cerebral artery, which was showing fetal hypoxia, the renal PI was not increased significantly. The fetal renal volume increased throughout the gestational period (r=0.834, p<0.0001) whereas in growth-retarded fetuses, all renal volume was below fifth percentile of normal fetuses. In growth-retarded fetuses, fetal renal volume was decreased significantly without change of the renal vascular flow. Therefore, the fetal renal volume measured by three-dimensional ultrasonography may be a helpful parameter in the diagnosis of growth-retarded fetuses.

  10. Experimental study on quantitative evaluation of slow pulsatile flow of CSF with cine MRI

    International Nuclear Information System (INIS)

    Matsuda, Masao

    1991-01-01

    The present study was designed to evaluate the slow pulsatile flow of cerebrospinal fluid (CSF) quantitatively with cine MRI in phantom experiment for the clinical application. The flow phantom was constructed from a plastic tube with a narrow channel to represent the central aqueduct. The phantom was filled with water to represent the CSF. The second tube filled with stationary water was positioned beside the flow phantom and acted as a control for no-flow signal strength. The ratio of signal intensity in regions of interest for the flow phantom and the control was measured. Not only the actual velocity curve of the flowing water through the phantom but also the temporal profile of signal intensity showed two main peaks with other small peaks in one cycle. This suggested a close relationship between signal intensity of cine MRI and flow velocity. A significant correlation between the signal intensity ratio and the velocity was obtained on cine MRI pulse sequences. Cine MRI was thus found to have the ability to give quantitative information about slow pulsatile flow. The most suitable pulse sequence was fast imaging with steady state free precession pulse sequence at the flip angle between 50 and 90 degrees. This preliminary study suggests that the slow pulsatile flow of CSF passing along the aqueduct can be visualized and measured. Thus, the sequence proposed has a potential for the investigation of normal and disturbed CSF circulation and the mapping of the flow pattern in different pathological conditions. (N.K.)

  11. Estimating right ventricular stroke work and the pulsatile work fraction in pulmonary hypertension.

    Science.gov (United States)

    Chemla, Denis; Castelain, Vincent; Zhu, Kaixian; Papelier, Yves; Creuzé, Nicolas; Hoette, Susana; Parent, Florence; Simonneau, Gérald; Humbert, Marc; Herve, Philippe

    2013-05-01

    The mean pulmonary artery pressure (mPAP) replaces mean systolic ejection pressure (msePAP) in the classic formula of right ventricular stroke work (RVSW) = (mPAP - RAP) × stroke volume, where RAP is mean right atrial pressure. Only the steady work is thus taken into account, not the pulsatile work, whereas pulmonary circulation is highly pulsatile. Our retrospective, high-fidelity pressure study tested the hypothesis that msePAP was proportional to mPAP, and looked at the implications for RVSW. Eleven patients with severe, precapillary pulmonary hypertension (PH) (six patients with idiopathic pulmonary arterial hypertension and five with chronic thromboembolic PH; mPAP = 57 ± 10 mm Hg) were studied at rest and during mild to moderate exercise. Eight non-PH control subjects were also studied at rest (mPAP = 16 ± 2 mm Hg). The msePAP was averaged from end diastole to dicrotic notch. In the full data set (53 pressure-flow points), mPAP ranged from 14 to 99.5 mm Hg, cardiac output from 2.38 to 11.1 L/min, and heart rate from 53 to 163 beats/min. There was a linear relationship between msePAP and mPAP (r² = 0.99). The msePAP matched 1.25 mPAP (bias, -0.5 ± 2.6 mm Hg). Results were similar in the resting non-PH group and in resting and the exercising PH group. This implies that the classic formula markedly underestimates RVSW and that the pulsatile work may be a variable 20% to 55% fraction of RVSW, depending on RAP and mPAP. At rest, RVSW in patients with PH was twice as high as that of the non-PH group (P work fraction was similar between the two groups (26 ± 4% vs 24 ± 1%) because of the counterbalancing effects of high RAP (11 ± 5 mm Hg vs 4 ± 2 mm Hg), which increases the fraction, and high mPAP, which decreases the fraction. Our study favored the use of an improved formula that takes into account the variable pulsatile work fraction: RVSW = (1.25 mPAP - RAP) × stroke volume. Increased RAP and increased mPAP have opposite effects on the pulsatile work

  12. Non-dimensional physics of pulsatile cardiovascular networks and energy efficiency.

    Science.gov (United States)

    Yigit, Berk; Pekkan, Kerem

    2016-01-01

    In Nature, there exist a variety of cardiovascular circulation networks in which the energetic ventricular load has both steady and pulsatile components. Steady load is related to the mean cardiac output (CO) and the haemodynamic resistance of the peripheral vascular system. On the other hand, the pulsatile load is determined by the simultaneous pressure and flow waveforms at the ventricular outlet, which in turn are governed through arterial wave dynamics (transmission) and pulse decay characteristics (windkessel effect). Both the steady and pulsatile contributions of the haemodynamic power load are critical for characterizing/comparing disease states and for predicting the performance of cardiovascular devices. However, haemodynamic performance parameters vary significantly from subject to subject because of body size, heart rate and subject-specific CO. Therefore, a 'normalized' energy dissipation index, as a function of the 'non-dimensional' physical parameters that govern the circulation networks, is needed for comparative/integrative biological studies and clinical decision-making. In this paper, a complete network-independent non-dimensional formulation that incorporates pulsatile flow regimes is developed. Mechanical design variables of cardiovascular flow systems are identified and the Buckingham Pi theorem is formally applied to obtain the corresponding non-dimensional scaling parameter sets. Two scaling approaches are considered to address both the lumped parameter networks and the distributed circulation components. The validity of these non-dimensional number sets is tested extensively through the existing empirical allometric scaling laws of circulation systems. Additional validation studies are performed using a parametric numerical arterial model that represents the transmission and windkessel characteristics, which are adjusted to represent different body sizes and non-dimensional haemodynamic states. Simulations demonstrate that the proposed non

  13. The use of a combined regimen of GnRH agonist plus a low-dose oral contraceptive improves the spontaneous pulsatile LH secretory characteristics in patients with polycycstic ovary disease after discontinuation of treatment.

    Science.gov (United States)

    Genazzani, A D; Battaglia, C; Gamba, O; Petraglia, F; Malavasi, B; Genazzani, A R

    2000-05-01

    The fertility rate in women with polycystic ovary disease (PCOD) is influenced by the type of treatment received. The present study evaluated the possible correlation between treatment and pulsatile release of gonadotropins. Spontaneous episodic secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) and hormonal parameters were monitored before and after 1, 3, and 6 months after treatments suspension. Twenty-four PCOD patients were randomly divided into two groups of 12 subjects. Group A was treated with gonadotropin-releasing hormone (GnRH)-analogue plus oral contraceptive (OC). Group B was treated only with OC. Both groups were treated for 6 months and followed up for 6 months. In all subjects the therapeutic regimens reduced the androgenic milieau and the gonadotropin plasma levels. Spontaneous pulsatile secretion of LH and FSH was significantly modified in both groups, but patients who received the combined regimen showed a significantly greater reduction of LH plasma levels and a significantly greater decrease of LH pulse amplitude throughout the 6 months after treatment suspension. Ferriman-Gallway score and ovarian volumes were significantly reduced in patients who received the combined treatment than in the OC-treated patients. These data support the evidence of a higher efficacy of the combination of GnRH-a + OC than OC alone in restoring a normal and adequate spontaneous episodic gonadotropin discharge and in decreasing Ferriman-Gallway score and ovarian volumes in patients with PCOD.

  14. Radiation effluent suppression system

    International Nuclear Information System (INIS)

    Watanabe, Atsushi.

    1992-01-01

    In a radiation release suppression system upon accident, an electromotive valve, a pneumatic operation valve or a manual operation valve is disposed to gas ventilation pipelines which are extended from both of a dry well and a wet well of a reactor container to a stuck. In addition, a combination filter of a metal fiber filter made of stainless steel etc. and an activated carbon fiber filter is disposed in the midway of pipelines in a reactor building. With such a constitution, the inside of the container can be depressurized (prevention of ruptures) and the amount of radioactive substances released to circumstances is remarkably suppressed by the effect of radioactive substance capturing effect of the metal fiber filter made of stainless steel etc. disposed in the vent pipe in the container and a radioactive substance capturing effect by the combination filter of the metal fiber filter made of stainless steel, etc. and the activated carbon fiber filter disposed in the gas ventilation pipelines even upon occurrence of an accident exceeding design basis. Systems can be simplified and minimized, and cost down can also be attained. (N.H.)

  15. Tonsillar pulsatility before and after surgical decompression for children with Chiari malformation type 1: an application for true fast imaging with steady state precession

    International Nuclear Information System (INIS)

    Radmanesh, Alireza; Greenberg, Jacob K.; Smyth, Matthew D.; Limbrick, David D.; Chatterjee, Arindam; Sharma, Aseem

    2015-01-01

    We hypothesize that surgical decompression for Chiari malformation type 1 (CM-1) is associated with statistically significant decrease in tonsillar pulsatility and that the degree of pulsatility can be reliably assessed regardless of the experience level of the reader. An Institutional Review Board (IRB)-approved Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study was performed on 22 children with CM-1 (8 males; mean age 11.4 years) who had cardiac-gated true-FISP sequence and phase-contrast cerebrospinal fluid (CSF) flow imaging as parts of routine magnetic resonance (MR) imaging before and after surgical decompression. The surgical technique (decompression with or without duraplasty) was recorded for each patient. Three independent radiologists with different experience levels assessed tonsillar pulsatility qualitatively and quantitatively and assessed peritonsillar CSF flow qualitatively. Results were analyzed. To evaluate reliability, Fleiss kappa for multiple raters on categorical variables and intra-class correlation for agreement in pulsatility ratings were calculated. After surgical decompression, the degree of tonsillar pulsatility appreciably decreased, confirmed by t test, both qualitatively (p values <0.001, <0.001, and 0.045 for three readers) and quantitatively (amount of decrease/p value for three readers 0.7 mm/<0.001, 0.7 mm/<0.001, and 0.5 mm/0.022). There was a better agreement among the readers in quantitative assessment of tonsillar pulsatility (kappa 0.753-0.834), compared to qualitative assessment of pulsatility (kappa 0.472-0.496) and qualitative assessment of flow (kappa 0.056 to 0.203). Posterior fossa decompression with duraplasty led to a larger decrease in tonsillar pulsatility, compared to posterior fossa decompression alone. Tonsillar pulsatility in CM-1 is significantly reduced after surgical decompression. Quantitative assessment of tonsillar pulsatility was more reliable across readers than

  16. Tonsillar pulsatility before and after surgical decompression for children with Chiari malformation type 1: an application for true fast imaging with steady state precession

    Energy Technology Data Exchange (ETDEWEB)

    Radmanesh, Alireza [University of California, San Francisco, Department of Radiology and Biomedical Imaging, San Francisco, CA (United States); Washington University School of Medicine, Mallinckrodt Institute of Radiology, St Louis, MO (United States); Greenberg, Jacob K.; Smyth, Matthew D.; Limbrick, David D. [Washington University School of Medicine, Department of Neurosurgery, St Louis, MO (United States); Chatterjee, Arindam; Sharma, Aseem [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St Louis, MO (United States)

    2015-04-01

    We hypothesize that surgical decompression for Chiari malformation type 1 (CM-1) is associated with statistically significant decrease in tonsillar pulsatility and that the degree of pulsatility can be reliably assessed regardless of the experience level of the reader. An Institutional Review Board (IRB)-approved Health Insurance Portability and Accountability Act (HIPAA)-compliant retrospective study was performed on 22 children with CM-1 (8 males; mean age 11.4 years) who had cardiac-gated true-FISP sequence and phase-contrast cerebrospinal fluid (CSF) flow imaging as parts of routine magnetic resonance (MR) imaging before and after surgical decompression. The surgical technique (decompression with or without duraplasty) was recorded for each patient. Three independent radiologists with different experience levels assessed tonsillar pulsatility qualitatively and quantitatively and assessed peritonsillar CSF flow qualitatively. Results were analyzed. To evaluate reliability, Fleiss kappa for multiple raters on categorical variables and intra-class correlation for agreement in pulsatility ratings were calculated. After surgical decompression, the degree of tonsillar pulsatility appreciably decreased, confirmed by t test, both qualitatively (p values <0.001, <0.001, and 0.045 for three readers) and quantitatively (amount of decrease/p value for three readers 0.7 mm/<0.001, 0.7 mm/<0.001, and 0.5 mm/0.022). There was a better agreement among the readers in quantitative assessment of tonsillar pulsatility (kappa 0.753-0.834), compared to qualitative assessment of pulsatility (kappa 0.472-0.496) and qualitative assessment of flow (kappa 0.056 to 0.203). Posterior fossa decompression with duraplasty led to a larger decrease in tonsillar pulsatility, compared to posterior fossa decompression alone. Tonsillar pulsatility in CM-1 is significantly reduced after surgical decompression. Quantitative assessment of tonsillar pulsatility was more reliable across readers than

  17. Algorithmic complexity of growth hormone release in humans

    Energy Technology Data Exchange (ETDEWEB)

    Prank, K.; Wagner, M.; Brabant, G. [Medical School Hannover (Germany)

    1996-12-31

    Most hormones are secreted in an pulsatile rather than in a constant manner. This temporal pattern of pulsatile hormone release plays an important role in the regulation of cellular function and structure. In healthy humans growth hormone (GH) secretion is characterized by distinct pulses whereas patients bearing a GH producing tumor accompanied with excessive secretion (acromegaly) exhibit a highly irregular pattern of GH release. It has been hypothesized that this highly disorderly pattern of GH release in acromegaly arises from random events in the GH-producing tumor under decreased normal control of GH secretion. Using a context-free grammar complexity measure (algorithmic complexity) in conjunction with random surrogate data sets we demonstrate that the temporal pattern of GH release in acromegaly is not significantly different from a variety of stochastic processes. In contrast, normal subjects clearly exhibit deterministic structure in their temporal patterns of GH secretion. Our results support the hypothesis that GH release in acromegaly is due to random events in the GH-producing tumorous cells which might become independent from hypothalamic regulation. 17 refs., 1 fig., 2 tabs.

  18. On heat transfer to pulsatile flow of a two-phase fluid

    Directory of Open Access Journals (Sweden)

    S. P. Chakraborty

    2005-09-01

    Full Text Available The problem of heat transfer to pulsatile flow of a two-phase fluid-particle system contained in a channel bounded by two infinitely long rigid impervious parallel walls has been studied in this paper. The solutions for the steady and the fluctuating temperature distributions are obtained. The rates of heat transfer at the walls are also calculated. The results are discussed numerically with graphical presentations. It is shown that the presence of the particles not only diminishes the steady and unsteady temperature fields but also decreases the reversal of heat flux at the hotter wall irrespective of the influences of other flow parameters.

  19. Pulsatile and steady-state hemodynamics of the human patella bone by diffuse optical spectroscopy

    International Nuclear Information System (INIS)

    Farzam, Parisa; Zirak, Peyman; Durduran, Turgut; Binzoni, Tiziano

    2013-01-01

    The cardiac cycle related pulsatile behavior of the absorption and scattering coefficients of diffuse light and the corresponding alterations in hemoglobin concentrations in the human patella was studied. The pulsations in scattering is considerably smaller than absorption. The difference in amplitude of absorption coefficient pulsations for different wavelengths was translated to pulsations in oxygenated and deoxygenated hemoglobin, which leads to strong pulsations in the total hemoglobin concentration and oxygen saturation. The physiological origin of the observed signals was confirmed by applying a thigh-cuff. Moreover, we have investigated the optical and physiological properties of the patella bone and their changes in response to arterial cuff occlusion. (paper)

  20. Pulsatile and steady-state hemodynamics of the human patella bone by diffuse optical spectroscopy.

    Science.gov (United States)

    Farzam, Parisa; Zirak, Peyman; Binzoni, Tiziano; Durduran, Turgut

    2013-08-01

    The cardiac cycle related pulsatile behavior of the absorption and scattering coefficients of diffuse light and the corresponding alterations in hemoglobin concentrations in the human patella was studied. The pulsations in scattering is considerably smaller than absorption. The difference in amplitude of absorption coefficient pulsations for different wavelengths was translated to pulsations in oxygenated and deoxygenated hemoglobin, which leads to strong pulsations in the total hemoglobin concentration and oxygen saturation. The physiological origin of the observed signals was confirmed by applying a thigh-cuff. Moreover, we have investigated the optical and physiological properties of the patella bone and their changes in response to arterial cuff occlusion.

  1. Pulsatile atheroprone shear stress affects the expression of transient receptor potential channels in human endothelial cells

    DEFF Research Database (Denmark)

    Thilo, Florian; Vorderwülbecke, Bernd J; Marki, Alex

    2012-01-01

    in comparison with endothelial cells grown under static conditions. There was a significant association between the expression of TRPC6 and tumor necrosis factor-α mRNA in human vascular tissue. No-flow and atheroprone flow conditions are equally characterized by an increase in the expression of tumor necrosis......The goal of the study was to assess whether pulsatile atheroprone shear stress modulates the expression of transient receptor potential (TRP) channels, TRPC3, TRPC6, TRPM7, and TRPV1 mRNA, in human umbilical vascular endothelial cells. Exposure of cultured vascular endothelial cells to defined...

  2. Association between the extent of sigmoid sinus dehiscence and an occurrence of pulsatile tinnitus: a retrospective imaging study

    International Nuclear Information System (INIS)

    Dong, C.; Zhao, P.; Liu, Z.; Xu, W.; Lv, H.; Pang, S.; Wang, Z.

    2016-01-01

    Aim: To assess the extent of sigmoid sinus dehiscence (SSD) on high-resolution computed tomography venography (HRCTV) or high-resolution computed tomography (HRCT) images in pulsatile tinnitus (PT) and non-PT groups to determine whether there is an association between the extent of SSD and occurrence of PT. Materials and methods: Twenty-eight SSD patients with ipsilateral PT and 28 age- and gender-matched SSD patients without PT who underwent HRCTV or HRCT were enrolled in this study and categorised into two groups: “PT group” and “non-PT group”. The extent of SSD in each group was calculated and compared. Results: The largest transverse diameter and largest vertical diameter of SSD in the PT group were 6.21±1.7 and 6.15±2.19 mm, respectively. The largest transverse diameter and largest vertical diameter of SSD in the non-PT group were 3.06±1.38 and 2.51±1.03 mm, respectively. The extent of SSD was statistically different between the two groups (p<0.001; p<0.001). Conclusions: As a cause of PT, SSD can also occur in individuals without PT symptoms. Preliminary findings suggest that there may be a potential correlation between the extent of SSD and an occurrence of PT. - Highlights: • We compared the extent of sigmoid sinus dehiscence in pulsatile tinnitus and non-pulsatile tinnitus groups. • The sigmoid sinus dehiscence in the pulsatile tinnitus patients was larger than those in non-pulsatile tinnitus patients. • There may be a potential correlation between the extent of sigmoid sinus dehiscence and an occurrence of pulsatile tinnitus.

  3. Correlation between vortices and wall shear stress in a curved artery model under pulsatile flow conditions

    Science.gov (United States)

    Cox, Christopher; Plesniak, Michael W.

    2017-11-01

    One of the most physiologically relevant factors within the cardiovascular system is the wall shear stress. The wall shear stress affects endothelial cells via mechanotransduction and atherosclerotic regions are strongly correlated with curvature and branching in the human vasculature, where the shear stress is both oscillatory and multidirectional. Also, the combined effect of curvature and pulsatility in cardiovascular flows produces unsteady vortices. In this work, our goal is to assess the correlation between multiple vortex pairs and wall shear stress. To accomplish this, we use an in-house high-order flux reconstruction Navier-Stokes solver to simulate pulsatile flow of a Newtonian blood-analog fluid through a rigid 180° curved artery model. We use a physiologically relevant flow rate and generate results using both fully developed and uniform entrance conditions, the latter motivated by the fact that flow upstream to a curved artery may not be fully developed. Under these two inflow conditions, we characterize the evolution of various vortex pairs and their subsequent effect on several wall shear stress metrics. Supported by GW Center for Biomimetics and Bioinspired Engineering.

  4. A pulsatile flow model for in vitro quantitative evaluation of prosthetic valve regurgitation

    Directory of Open Access Journals (Sweden)

    S. Giuliatti

    2000-03-01

    Full Text Available A pulsatile pressure-flow model was developed for in vitro quantitative color Doppler flow mapping studies of valvular regurgitation. The flow through the system was generated by a piston which was driven by stepper motors controlled by a computer. The piston was connected to acrylic chambers designed to simulate "ventricular" and "atrial" heart chambers. Inside the "ventricular" chamber, a prosthetic heart valve was placed at the inflow connection with the "atrial" chamber while another prosthetic valve was positioned at the outflow connection with flexible tubes, elastic balloons and a reservoir arranged to mimic the peripheral circulation. The flow model was filled with a 0.25% corn starch/water suspension to improve Doppler imaging. A continuous flow pump transferred the liquid from the peripheral reservoir to another one connected to the "atrial" chamber. The dimensions of the flow model were designed to permit adequate imaging by Doppler echocardiography. Acoustic windows allowed placement of transducers distal and perpendicular to the valves, so that the ultrasound beam could be positioned parallel to the valvular flow. Strain-gauge and electromagnetic transducers were used for measurements of pressure and flow in different segments of the system. The flow model was also designed to fit different sizes and types of prosthetic valves. This pulsatile flow model was able to generate pressure and flow in the physiological human range, with independent adjustment of pulse duration and rate as well as of stroke volume. This model mimics flow profiles observed in patients with regurgitant prosthetic valves.

  5. A High Performance Pulsatile Pump for Aortic Flow Experiments in 3-Dimensional Models.

    Science.gov (United States)

    Chaudhury, Rafeed A; Atlasman, Victor; Pathangey, Girish; Pracht, Nicholas; Adrian, Ronald J; Frakes, David H

    2016-06-01

    Aortic pathologies such as coarctation, dissection, and aneurysm represent a particularly emergent class of cardiovascular diseases. Computational simulations of aortic flows are growing increasingly important as tools for gaining understanding of these pathologies, as well as for planning their surgical repair. In vitro experiments are required to validate the simulations against real world data, and the experiments require a pulsatile flow pump system that can provide physiologic flow conditions characteristic of the aorta. We designed a newly capable piston-based pulsatile flow pump system that can generate high volume flow rates (850 mL/s), replicate physiologic waveforms, and pump high viscosity fluids against large impedances. The system is also compatible with a broad range of fluid types, and is operable in magnetic resonance imaging environments. Performance of the system was validated using image processing-based analysis of piston motion as well as particle image velocimetry. The new system represents a more capable pumping solution for aortic flow experiments than other available designs, and can be manufactured at a relatively low cost.

  6. Visualization and quantitative analysis of the CSF pulsatile flow with cine MR phase imaging

    International Nuclear Information System (INIS)

    Katayama, Shinji; Itoh, Takahiko; Kinugasa, Kazushi; Asari, Shoji; Nishimoto, Akira; Tsuchida, Shohei; Ono, Atsushi; Ikezaki, Yoshikazu; Yoshitome, Eiji.

    1991-01-01

    The visualization and the quantitative analysis of the CSF pulsatile flow were performed on ten healthy volunteers with cine MR phase imaging, a combination of the phase-contrast technique and the cardiac-gating technique. The velocities appropriate for the visualization and the quantitative analysis of the CSF pulsatile flow were from 6.0 cm/sec to 15.0 cm/sec. The applicability of this method for the quantitative analysis was proven with a steady-flow phantom. Phase images clearly demonstrated a to-and-fro motion of the CSF flow in the anterior subarachnoid space and in the posterior subarachnoid space. The flow pattern of CSF on healthy volunteers depends on the cardiac cycle. In the anterior subarachnoid space, the cephalic CSF flow continued until a 70-msec delay after the R-wave of the ECG and then reversed to caudal. At 130-190 msec, the caudal CSF flow reached its maximum velocity; thereafter it reversed again to cephalic. The same turn appeared following the phase, but then the amplitude decreased. The cephalic peaked at 370-430 msec, while the caudal peaked at 490-550 msec. The flow pattern of the CSF flow in the posterior subarachnoid space was almost identical to that in the anterior subarachnoid space. Cine MR phase imaging is thus useful for the visualization and the quantitative analysis of the CSF pulsative flow. (author)

  7. Laser Doppler anemometer measurements of pulsatile flow in a model carotid bifurcation.

    Science.gov (United States)

    Ku, D N; Giddens, D P

    1987-01-01

    Hemodynamics at the human carotid bifurcation is important to the understanding of atherosclerotic plaque initiation and progression as well as to the diagnosis of clinically important disease. Laser Doppler anemometry was performed in a large scale model of an average human carotid. Pulsatile waveforms and physiologic flow divisions were incorporated. Disturbance levels and shear stresses were computed from ensemble averages of the velocity waveform measurements. Flow in the common carotid was laminar and symmetric. Flow patterns in the sinus, however, were complex and varied considerably during the cycle. Strong helical patterns and outer wall flow separation waxed and waned during each systole. The changing flow patterns resulted in an oscillatory shear stress at the outer wall ranging from -13 to 9 dyn cm-2 during systole with a time-averaged mean of only -0.5 dyn cm-2. This contrasts markedly with an inner wall shear stress range of 17-50, (mean 26) dyn cm-2. The region of transient separation was confined to the carotid sinus outer wall with no reverse velocities detected in the distal internal carotid. Notable disturbance velocities were also time-dependent, occurring only during the deceleration phase of systole and the beginning of diastole. The present pulsatile flow studies have aided in identifying hemodynamic conditions which correlate with early intimal thickening and predict the physiologic level of flow disturbances in the bulb of undiseased internal carotid arteries.

  8. Biological time series analysis using a context free language: applicability to pulsatile hormone data.

    Directory of Open Access Journals (Sweden)

    Dennis A Dean

    Full Text Available We present a novel approach for analyzing biological time-series data using a context-free language (CFL representation that allows the extraction and quantification of important features from the time-series. This representation results in Hierarchically AdaPtive (HAP analysis, a suite of multiple complementary techniques that enable rapid analysis of data and does not require the user to set parameters. HAP analysis generates hierarchically organized parameter distributions that allow multi-scale components of the time-series to be quantified and includes a data analysis pipeline that applies recursive analyses to generate hierarchically organized results that extend traditional outcome measures such as pharmacokinetics and inter-pulse interval. Pulsicons, a novel text-based time-series representation also derived from the CFL approach, are introduced as an objective qualitative comparison nomenclature. We apply HAP to the analysis of 24 hours of frequently sampled pulsatile cortisol hormone data, which has known analysis challenges, from 14 healthy women. HAP analysis generated results in seconds and produced dozens of figures for each participant. The results quantify the observed qualitative features of cortisol data as a series of pulse clusters, each consisting of one or more embedded pulses, and identify two ultradian phenotypes in this dataset. HAP analysis is designed to be robust to individual differences and to missing data and may be applied to other pulsatile hormones. Future work can extend HAP analysis to other time-series data types, including oscillatory and other periodic physiological signals.

  9. Pulsatile flow of blood and heat transfer with variable viscosity under magnetic and vibration environment

    International Nuclear Information System (INIS)

    Shit, G.C.; Majee, Sreeparna

    2015-01-01

    Unsteady flow of blood and heat transfer characteristics in the neighborhood of an overlapping constricted artery have been investigated in the presence of magnetic field and whole body vibration. The laminar flow of blood is taken to be incompressible and Newtonian fluid with variable viscosity depending upon temperature with an aim to provide resemblance to the real situation in the physiological system. The unsteady flow mechanism in the constricted artery is subjected to a pulsatile pressure gradient arising from systematic functioning of the heart and from the periodic body acceleration. The numerical computation has been performed using finite difference method by developing Crank–Nicolson scheme. The results show that the volumetric flow rate, skin-friction and the rate of heat transfer at the wall are significantly altered in the downstream of the constricted region. The axial velocity profile, temperature and flow rate increases with increase in temperature dependent viscosity, while the opposite trend is observed in the case of skin-friction and flow impedance. - Highlights: • We have investigated the pulsatile MHD flow of blood and heat transfer in arteries. • The influence of periodic body acceleration has been taken into account. • The temperature dependent viscosity of blood is considered. • The variable viscosity has an increasing effect on blood flow and heat transfer. • The overall temperature distribution enhances in the presence of magnetic field

  10. Pulsatile flow of blood and heat transfer with variable viscosity under magnetic and vibration environment

    Energy Technology Data Exchange (ETDEWEB)

    Shit, G.C., E-mail: gopal_iitkgp@yahoo.co.in; Majee, Sreeparna

    2015-08-15

    Unsteady flow of blood and heat transfer characteristics in the neighborhood of an overlapping constricted artery have been investigated in the presence of magnetic field and whole body vibration. The laminar flow of blood is taken to be incompressible and Newtonian fluid with variable viscosity depending upon temperature with an aim to provide resemblance to the real situation in the physiological system. The unsteady flow mechanism in the constricted artery is subjected to a pulsatile pressure gradient arising from systematic functioning of the heart and from the periodic body acceleration. The numerical computation has been performed using finite difference method by developing Crank–Nicolson scheme. The results show that the volumetric flow rate, skin-friction and the rate of heat transfer at the wall are significantly altered in the downstream of the constricted region. The axial velocity profile, temperature and flow rate increases with increase in temperature dependent viscosity, while the opposite trend is observed in the case of skin-friction and flow impedance. - Highlights: • We have investigated the pulsatile MHD flow of blood and heat transfer in arteries. • The influence of periodic body acceleration has been taken into account. • The temperature dependent viscosity of blood is considered. • The variable viscosity has an increasing effect on blood flow and heat transfer. • The overall temperature distribution enhances in the presence of magnetic field.

  11. Ocular Perfusion Pressure and Pulsatile Ocular Blood Flow in Normal and Systemic Hypertensive Patients.

    Science.gov (United States)

    Kanadani, Fabio N; Figueiredo, Carlos R; Miranda, Rafaela Morais; Cunha, Patricia Lt; M Kanadani, Tereza Cristina; Dorairaj, Syril

    2015-01-01

    Glaucomatous neuropathy can be a consequence of insufficient blood supply, increase in intraocular pressure (IOP), or other risk factors that diminish the ocular blood flow. To determine the ocular perfusion pressure (OPP) in normal and systemic hypertensive patients. One hundred and twenty-one patients were enrolled in this prospective and comparative study and underwent a complete ophthalmologic examination including slit lamp examination, Goldmann applanation tonometry, stereoscopic fundus examination, and pulsatile ocular blood flow (POBF) measurements. The OPP was calculated as being the medium systemic arterial pressure (MAP) less the IOP. Only right eye values were considered for calculations using Student's t-test. The mean age of the patients was 57.5 years (36-78), and 68.5% were women. There was a statistically significant difference in the OPP of the normal and systemic hypertensive patients (p cite this article: Kanadani FN, Figueiredo CR, Miranda RM, Cunha PLT, Kanadani TCM, Dorairaj S. Ocular Perfusion Pressure and Pulsatile Ocular Blood Flow in Normal and Systemic Hypertensive Patients. J Curr Glaucoma Pract 2015;9(1):16-19.

  12. Computational fluid dynamics analysis and PIV validation of a bionic vortex flow pulsatile LVAD.

    Science.gov (United States)

    Xu, Liang; Yang, Ming; Ye, Lin; Dong, Zhaopeng

    2015-01-01

    Hemocompatibility is highly affected by the flow field in Left Ventricular Assistant Devices (LVAD). An asymmetric inflow and outflow channel arrangement with a 45° intersection angle with respect to the blood chamber is proposed to approximate the vascular structure of the aorta and left atrium on the left ventricle. The structure is expected to develop uninterruptible vortex flow state which is similar to the flow state in human left ventricle. The Computational Fluid Dynamics (CFD) asymmetric model is simulated using ANSYS workbench. To validate the velocity field calculated by CFD, a Particle Image Velocimetry (PIV) experiment is conducted. The CFD results show that the proposed blood chamber could generate a shifting vortex flow that would be redirected to the aorta during ejection to form a persistent recirculating flow state, which is similar to the echocardiographic flow state in left ventricle. Both the PIV and the CFD results show the development of a persistent vortex during the pulsatile period. Comparison of the qualitative flow pattern and quantitative probed velocity histories in a pulsatile period shows a good agreement between the CFD and PIV data. The goal of developing persistent quasi intra-ventricle vortex flow state in LVAD is realized.

  13. Aneurysm pulsatility after endovascular exclusion: an experimental study using human aortic aneurysms

    Directory of Open Access Journals (Sweden)

    Hussein Amin Orra

    2008-01-01

    Full Text Available OBJECTIVE: To measure the pulsatility of human aneurysms before and after complete exclusion with an endograft. METHOD: Five aortic aneurysms obtained during necropsy were submitted to pulsatile perfusion before and after implantation of a bifurcated endograft. The specimens were contained in a closed chamber filled with saline solution. A vertical tube attached to the chamber was used to measure volume dislocation in each systole. Mural thrombus was kept intact, and the space around the device was filled with human blood. After each experiment, the aneurysm was opened to check for the correct positioning and attachment of the device. RESULTS: The level of the saline column oscillated during pulsation in each case, with respective amplitudes of 17, 16, 13, 7, and 25 cm before the endograft insertion. After the insertion, the amplitudes dropped to 13, 12, 9, 3.5, and 23 cm, respectively. The differences were not significant. During the post-experimental examination, all devices were found to be in position and well attached to the neck and iliacs. No endoleak was detected during perfusion or by visual inspection. CONCLUSION: Pulsation of an endograft is transmitted to the aneurysm wall even in the absence of endoleak, and should not be interpreted as procedural failure.

  14. Supplementation with a recombinant human chorionic gonadotropin microdose leads to similar outcomes in ovarian stimulation with recombinant follicle-stimulating hormone using either a gonadotropin-releasing hormone agonist or antagonist for pituitary suppression.

    Science.gov (United States)

    Cavagna, Mario; Maldonado, Luiz Guilherme Louzada; de Souza Bonetti, Tatiana Carvalho; de Almeida Ferreira Braga, Daniela Paes; Iaconelli, Assumpto; Borges, Edson

    2010-06-01

    To compare the outcomes of protocols for ovarian stimulation with recombinant hCG microdose, with GnRH agonists and antagonists for pituitary suppression. Prospective nonrandomized clinical trial. A private assisted reproduction center. We studied 182 patients undergoing intracytoplasmic sperm injection (ICSI) cycles, allocated into two groups: GnRH agonist group, in which patients received a GnRH agonist (n = 73), and a GnRH antagonist group, in which patients were administered a GnRH antagonist for pituitary suppression (n = 109). Pituitary suppression with GnRH agonist or GnRH antagonist. Ovarian stimulation carried out with recombinant FSH and supplemented with recombinant hCG microdose. Total dose of recombinant FSH and recombinant hCG administered; E(2) concentrations and endometrial width on the day of hCG trigger; number of follicles aspirated, oocytes and mature oocytes retrieved; fertilization, pregnancy (PR), implantation, and miscarriage rates. The total dose of recombinant FSH and recombinant hCG administered were similar between groups, as were the E(2) concentrations and endometrial width. The number of follicles aspirated, oocytes, and metaphase II oocytes collected were also comparable. There were no statistically significant differences in fertilization, PR, implantation, and miscarriage rates in the GnRH agonist and GnRH antagonist groups. When using recombinant hCG microdose supplementation for controlled ovarian stimulation (COS), there are no differences in laboratory or clinical outcomes with the use of either GnRH antagonist or agonist for pituitary suppression. Copyright (c) 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

  15. Jointly Amplified Basal and Pulsatile Growth Hormone (GH) Secretion and Increased Process Irregularity in Women with Anorexia Nervosa

    DEFF Research Database (Denmark)

    Støving, R K; Veldhuis, J D; Flyvbjerg, A

    1999-01-01

    Anorexia nervosa (AN) is associated with multiple endocrine alterations. In the majority of AN patients, basal and GHRH-stimulated serum GH levels are increased. The metabolic effects of GH are known to be related to its pulsatile secretory pattern. The present study was performed to examine GH...

  16. Pulsatile drug delivery to ileo-colonic segments by structured incorporation of disintegrants in pH-responsive polymer coatings

    NARCIS (Netherlands)

    Schellekens, R.C.A.; Stellaard, F.; Mitrovic, D.; Stuurman, F.E.; Kosterink, J.G.W.; Frijlink, H.W.

    2008-01-01

    Conventional pH-responsive coatings used for oral drug delivery to the lower parts of the gastro-intestinal tract often show a poor performance. A new system for site-specific pulsatile delivery in the ileo-colonic regions is described. The system is based on the non-percolating incorporation of

  17. Enhancement of arterial pressure pulsatility by controlling continuous-flow left ventricular assist device flow rate in mock circulatory system

    NARCIS (Netherlands)

    Bozkurt, S.; van de Vosse, F.N.; Rutten, M.C.M.

    Continuous-flow left ventricular assist devices (CF-LVADs) generally operate at a constant speed, which reduces pulsatility in the arteries and may lead to complications such as functional changes in the vascular system, gastrointestinal bleeding, or both. The purpose of this study is to increase

  18. Fluid-structure interaction modeling of aneurysmal arteries under steady-state and pulsatile blood flow: a stability analysis.

    Science.gov (United States)

    Sharzehee, Mohammadali; Khalafvand, Seyed Saeid; Han, Hai-Chao

    2018-02-01

    Tortuous aneurysmal arteries are often associated with a higher risk of rupture but the mechanism remains unclear. The goal of this study was to analyze the buckling and post-buckling behaviors of aneurysmal arteries under pulsatile flow. To accomplish this goal, we analyzed the buckling behavior of model carotid and abdominal aorta with aneurysms by utilizing fluid-structure interaction (FSI) method with realistic waveforms boundary conditions. FSI simulations were done under steady-state and pulsatile flow for normal (1.5) and reduced (1.3) axial stretch ratios to investigate the influence of aneurysm, pulsatile lumen pressure and axial tension on stability. Our results indicated that aneurysmal artery buckled at the critical buckling pressure and its deflection nonlinearly increased with increasing lumen pressure. Buckling elevates the peak stress (up to 118%). The maximum aneurysm wall stress at pulsatile FSI flow was (29%) higher than under static pressure at the peak lumen pressure of 130 mmHg. Buckling results show an increase in lumen shear stress at the inner side of the maximum deflection. Vortex flow was dramatically enlarged with increasing lumen pressure and artery diameter. Aneurysmal arteries are more susceptible than normal arteries to mechanical instability which causes high stresses in the aneurysm wall that could lead to aneurysm rupture.

  19. Polycystic ovarian disease unmasked by pulsatile GnRH therapy in a subgroup of women with hypothalamic amenorrhea.

    Science.gov (United States)

    Mattle, Verena; Bilgyicildirim, Aysen; Hadziomerovic, Dijana; Ott, Helmut W; Zervomanolakis, Ioannis; Leyendecker, Gerhard; Wildt, Ludwig

    2008-02-01

    To present the observation in six out of 120 women treated with pulsatile GnRH for ovulation induction, who developed hyperandrogenemia and polycystic ovaries during treatment. Clinical observation. Department of Gynecologic Endocrinology and Reproductive Medicine, Medical University of Innsbruck, Austria. A total of 120 women initially diagnosed as suffering from primary or secondary hypothalamic amenorrhea were treated for ovulation induction with pulsatile administration of GnRH for up to 140 days. There was no indication of the presence of polycystic ovaries or hyperandrogenemia before therapy. Pulsatile GnRH therapy using the Zyklomat pump. Ovulatory menstrual cycles. Initially, all patients responded to pulsatile GnRH administration with ovulation and corpus luteum formation. During continuation of treatment, 6 patients developed an increase in LH and LH/FSH ratio as well as a progressive rise in serum T levels resulting in hyperandrogenemia. This was accompanied by the development of polycystic ovaries and cessation of follicular maturation. We conclude from these observations that restoration of normal GnRH stimulation of the pituitary gland can result in the development of hyperandrogenemia and polycystic ovaries, suggesting a pituitary or ovarian defect underlying the pathogenesis of this disorder.

  20. Pulsatile delivery of a leucine supplement during long-term continuous enteral feeding enhances lean growth in term neonatal pigs

    Science.gov (United States)

    Neonatal pigs are used as a model to study and optimize the clinical treatment of infants who are unable to maintain oral feeding. Using this model, we have previously shown that pulsatile administration of leucine during continuous feeding over 24 h via orogastric tube enhanced protein synthesis in...

  1. Secondary flow structures in a 180∘ elastic curved vessel with torsion under steady and pulsatile inflow conditions

    Science.gov (United States)

    Najjari, Mohammad Reza; Plesniak, Michael W.

    2017-11-01

    Secondary flow vortical structures were investigated in an elastic 180° curved pipe with and without torsion under steady and pulsatile flow using particle image velocimetry (PIV). The elastic thin-walled curved pipes were constructed using Sylgard 184, and inserted into a bath of refractive index matched fluid to perform PIV. A vortex identification method was employed to identify various vortical structures in the flow. The secondary flow structures in the planar compliant model with dilatation of 0.61%-3.23% under pulsatile flow rate were compared with the rigid vessel model results, and it was found that local vessel compliance has a negligible effect on secondary flow morphology. The secondary flow structures were found to be more sensitive to out of plane curvature (torsion) than to vessel compliance. Torsion distorts the symmetry of secondary flow and results in more complex vortical structures in both steady and pulsatile flows. In high Re number steady flow with torsion, a single dominant vortical structure can be detected at the middle of the 90° cross section. In pulsatile flow with torsion, the split-Dean and Lyne-type vortices with same rotation direction originating from opposite sides of the cross section tend to merge together. supported by GW Center for Biomimetics and Bioinspired Engineering.

  2. Force Trends and Pulsatility for Catheter Contact Identification in Intracardiac Electrograms during Arrhythmia Ablation.

    Science.gov (United States)

    Rivas-Lalaleo, David; Muñoz-Romero, Sergio; Huerta, Mónica; Erazo-Rodas, Mayra; Sánchez-Muñoz, Juan José; Rojo-Álvarez, José Luis; García-Alberola, Arcadi

    2018-05-02

    The intracardiac electrical activation maps are commonly used as a guide in the ablation of cardiac arrhythmias. The use of catheters with force sensors has been proposed in order to know if the electrode is in contact with the tissue during the registration of intracardiac electrograms (EGM). Although threshold criteria on force signals are often used to determine the catheter contact, this may be a limited criterion due to the complexity of the heart dynamics and cardiac vorticity. The present paper is devoted to determining the criteria and force signal profiles that guarantee the contact of the electrode with the tissue. In this study, we analyzed 1391 force signals and their associated EGM recorded during 2 and 8 s, respectively, in 17 patients (82 ± 60 points per patient). We aimed to establish a contact pattern by first visually examining and classifying the signals, according to their likely-contact joint profile and following the suggestions from experts in the doubtful cases. First, we used Principal Component Analysis to scrutinize the force signal dynamics by analyzing the main eigen-directions, first globally and then grouped according to the certainty of their tissue-catheter contact. Second, we used two different linear classifiers (Fisher discriminant and support vector machines) to identify the most relevant components of the previous signal models. We obtained three main types of eigenvectors, namely, pulsatile relevant, non-pulsatile relevant, and irrelevant components. The classifiers reached a moderate to sufficient discrimination capacity (areas under the curve between 0.84 and 0.95 depending on the contact certainty and on the classifier), which allowed us to analyze the relevant properties in the force signals. We conclude that the catheter-tissue contact profiles in force recordings are complex and do not depend only on the signal intensity being above a threshold at a single time instant, but also on time pulsatility and trends. These

  3. Stability of Carotid Artery Under Steady-State and Pulsatile Blood Flow: A Fluid–Structure Interaction Study

    Science.gov (United States)

    Saeid Khalafvand, Seyed; Han, Hai-Chao

    2015-01-01

    It has been shown that arteries may buckle into tortuous shapes under lumen pressure, which in turn could alter blood flow. However, the mechanisms of artery instability under pulsatile flow have not been fully understood. The objective of this study was to simulate the buckling and post-buckling behaviors of the carotid artery under pulsatile flow using a fully coupled fluid–structure interaction (FSI) method. The artery wall was modeled as a nonlinear material with a two-fiber strain-energy function. FSI simulations were performed under steady-state flow and pulsatile flow conditions with a prescribed flow velocity profile at the inlet and different pressures at the outlet to determine the critical buckling pressure. Simulations were performed for normal (160 ml/min) and high (350 ml/min) flow rates and normal (1.5) and reduced (1.3) axial stretch ratios to determine the effects of flow rate and axial tension on stability. The results showed that an artery buckled when the lumen pressure exceeded a critical value. The critical mean buckling pressure at pulsatile flow was 17–23% smaller than at steady-state flow. For both steady-state and pulsatile flow, the high flow rate had very little effect (<5%) on the critical buckling pressure. The fluid and wall stresses were drastically altered at the location with maximum deflection. The maximum lumen shear stress occurred at the inner side of the bend and maximum tensile wall stresses occurred at the outer side. These findings improve our understanding of artery instability in vivo. PMID:25761257

  4. Stability of carotid artery under steady-state and pulsatile blood flow: a fluid-structure interaction study.

    Science.gov (United States)

    Saeid Khalafvand, Seyed; Han, Hai-Chao

    2015-06-01

    It has been shown that arteries may buckle into tortuous shapes under lumen pressure, which in turn could alter blood flow. However, the mechanisms of artery instability under pulsatile flow have not been fully understood. The objective of this study was to simulate the buckling and post-buckling behaviors of the carotid artery under pulsatile flow using a fully coupled fluid-structure interaction (FSI) method. The artery wall was modeled as a nonlinear material with a two-fiber strain-energy function. FSI simulations were performed under steady-state flow and pulsatile flow conditions with a prescribed flow velocity profile at the inlet and different pressures at the outlet to determine the critical buckling pressure. Simulations were performed for normal (160 ml/min) and high (350 ml/min) flow rates and normal (1.5) and reduced (1.3) axial stretch ratios to determine the effects of flow rate and axial tension on stability. The results showed that an artery buckled when the lumen pressure exceeded a critical value. The critical mean buckling pressure at pulsatile flow was 17-23% smaller than at steady-state flow. For both steady-state and pulsatile flow, the high flow rate had very little effect (<5%) on the critical buckling pressure. The fluid and wall stresses were drastically altered at the location with maximum deflection. The maximum lumen shear stress occurred at the inner side of the bend and maximum tensile wall stresses occurred at the outer side. These findings improve our understanding of artery instability in vivo.

  5. Does polycystic ovarian morphology influence the response to treatment with pulsatile GnRH in functional hypothalamic amenorrhea?

    Science.gov (United States)

    Dumont, Agathe; Dewailly, Didier; Plouvier, Pauline; Catteau-Jonard, Sophie; Robin, Geoffroy

    2016-04-29

    Pulsatile GnRH therapy is the gold standard treatment for ovulation induction in women having functional hypothalamic amenorrhea (FHA). The use of pulsatile GnRH therapy in FHA patients with polycystic ovarian morphology (PCOM), called "FHA-PCOM", has been little studied in the literature and results remain contradictory. The aim of this study was to compare the outcomes of pulsatile GnRH therapy for ovulation induction between FHA and "FHA-PCOM" patients in order to search for an eventual impact of PCOM. Retrospective study from August 2002 to June 2015, including 27 patients with FHA and 40 "FHA-PCOM" patients (85 and 104 initiated cycles, respectively) treated by pulsatile GnRH therapy for induction ovulation. The two groups were similar except for markers of PCOM (follicle number per ovary, serum Anti-Müllerian Hormone level and ovarian area), which were significantly higher in patients with "FHA-PCOM". There was no significant difference between the groups concerning the ovarian response: with equivalent doses of GnRH, both groups had similar ovulation (80.8 vs 77.7 %, NS) and excessive response rates (12.5 vs 10.6 %, NS). There was no significant difference in on-going pregnancy rates (26.9 vs 20 % per initiated cycle, NS), as well as in miscarriage, multiple pregnancy or biochemical pregnancy rates. Pulsatile GnRH seems to be a successful and safe method for ovulation induction in "FHA-PCOM" patients. If results were confirmed by prospective studies, GnRH therapy could therefore become a first-line treatment for this specific population, just as it is for women with FHA without PCOM.

  6. Implantable batteryless device for on-demand and pulsatile insulin administration

    Science.gov (United States)

    Lee, Seung Ho; Lee, Young Bin; Kim, Byung Hwi; Lee, Cheol; Cho, Young Min; Kim, Se-Na; Park, Chun Gwon; Cho, Yong-Chan; Choy, Young Bin

    2017-04-01

    Many implantable systems have been designed for long-term, pulsatile delivery of insulin, but the lifetime of these devices is limited by the need for battery replacement and consequent replacement surgery. Here we propose a batteryless, fully implantable insulin pump that can be actuated by a magnetic field. The pump is prepared by simple-assembly of magnets and constituent units and comprises a drug reservoir and actuator equipped with a plunger and barrel, each assembled with a magnet. The plunger moves to noninvasively infuse insulin only when a magnetic field is applied on the exterior surface of the body. Here we show that the dose is easily controlled by varying the number of magnet applications. Also, pump implantation in diabetic rats results in profiles of insulin concentration and decreased blood glucose levels similar to those observed in rats treated with conventional subcutaneous insulin injections.

  7. PIV Measurement of Pulsatile Flows in 3D Curved Tubes Using Refractive Index Matching Method

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Hyeon Ji; Ji, Ho Seong; Kim, Kyung Chun [Pusan Nat’l Univ., Busan (Korea, Republic of)

    2016-08-15

    Three-dimensional models of stenosis blood vessels were prepared using a 3D printer. The models included a straight pipe with axisymmetric stenosis and a pipe that was bent 10° from the center of stenosis. A refractive index matching method was utilized to measure accurate velocity fields inside the 3D tubes. Three different pulsatile flows were generated and controlled by changing the rotational speed frequency of the peristaltic pump. Unsteady velocity fields were measured by a time-resolved particle image velocimetry method. Periodic shedding of vortices occurred and moves depended on the maximum velocity region. The sizes and the positions of the vortices and symmetry are influenced by mean Reynolds number and tube geometry. In the case of the bent pipe, a recirculation zone observed at the post-stenosis could explain the possibility of blood clot formation and blood clot adhesion in view of hemodynamics.

  8. PIV Measurement of Pulsatile Flows in 3D Curved Tubes Using Refractive Index Matching Method

    International Nuclear Information System (INIS)

    Hong, Hyeon Ji; Ji, Ho Seong; Kim, Kyung Chun

    2016-01-01

    Three-dimensional models of stenosis blood vessels were prepared using a 3D printer. The models included a straight pipe with axisymmetric stenosis and a pipe that was bent 10° from the center of stenosis. A refractive index matching method was utilized to measure accurate velocity fields inside the 3D tubes. Three different pulsatile flows were generated and controlled by changing the rotational speed frequency of the peristaltic pump. Unsteady velocity fields were measured by a time-resolved particle image velocimetry method. Periodic shedding of vortices occurred and moves depended on the maximum velocity region. The sizes and the positions of the vortices and symmetry are influenced by mean Reynolds number and tube geometry. In the case of the bent pipe, a recirculation zone observed at the post-stenosis could explain the possibility of blood clot formation and blood clot adhesion in view of hemodynamics.

  9. Seasonal and pulsatile dynamics of thyrotropin and leptin in mares maintained under a constant energy balance.

    Science.gov (United States)

    Buff, P R; Messer, N T; Cogswell, A M; Johnson, P J; Keisler, D H; Ganjam, V K

    2007-11-01

    The objective of this study was to determine if seasonal and/or pulsatile variations occur in plasma concentrations of thyrotropin (TSH) and leptin in mares while maintaining a constant energy balance. Blood samples were collected every 20 min during a 24h period in winter and again in summer from six Quarter Horse type mares. Plasma concentrations of TSH, leptin, and T(4) were determined by radioimmunoassay. No differences were observed in body weight between winter (388.1+/-12.5 kg) and summer (406.2+/-12.5 kg; P=0.11). Plasma concentrations of TSH were greater in the summer (2.80+/-0.07 ng/ml) when compared to winter (0.97+/-0.07 ng/ml; P<0.001). Pulse frequency of TSH was not different between winter (6.17+/-0.78 pulses/24h) and summer (5.33+/-0.78 pulses/24h; P=0.49). Mean TSH pulse amplitude, pulse area, and area under the curve were all greater in summer compared to winter (3.11+/-0.10 ng/ml versus 1.20+/-0.10 ng/ml, 24.86+/-0.10 ng/ml min versus 13.46+/-1.90 ng/ml min, 3936+/-72.93 ng/ml versus 1284+/-72.93 ng/ml, respectively; P<0.01). Mean concentrations of leptin were greater in summer (2.48+/-0.17 ng/ml) compared to winter (0.65+/-0.17 ng/ml; P<0.001). Pulsatile secretion patterns of leptin were not observed in any horses during experimentation. Mean concentrations of T(4) were greater in winter (20.3+/-0.4 ng/ml) compared to summer (18.2+/-0.4 ng/ml; P<0.001). These seasonal differences between winter and summer provide evidence of possible seasonal regulation of TSH and leptin.

  10. Cardiac-driven Pulsatile Motion of Intracranial Cerebrospinal Fluid Visualized Based on a Correlation Mapping Technique.

    Science.gov (United States)

    Yatsushiro, Satoshi; Sunohara, Saeko; Hayashi, Naokazu; Hirayama, Akihiro; Matsumae, Mitsunori; Atsumi, Hideki; Kuroda, Kagayaki

    2018-04-10

    A correlation mapping technique delineating delay time and maximum correlation for characterizing pulsatile cerebrospinal fluid (CSF) propagation was proposed. After proofing its technical concept, this technique was applied to healthy volunteers and idiopathic normal pressure hydrocephalus (iNPH) patients. A time-resolved three dimensional-phase contrast (3D-PC) sampled the cardiac-driven CSF velocity at 32 temporal points per cardiac period at each spatial location using retrospective cardiac gating. The proposed technique visualized distributions of propagation delay and correlation coefficient of the PC-based CSF velocity waveform with reference to a waveform at a particular point in the CSF space. The delay time was obtained as the amount of time-shift, giving the maximum correlation for the velocity waveform at an arbitrary location with that at the reference location. The validity and accuracy of the technique were confirmed in a flow phantom equipped with a cardiovascular pump. The technique was then applied to evaluate the intracranial CSF motions in young, healthy (N = 13), and elderly, healthy (N = 13) volunteers and iNPH patients (N = 13). The phantom study demonstrated that root mean square error of the delay time was 2.27%, which was less than the temporal resolution of PC measurement used in this study (3.13% of a cardiac cycle). The human studies showed a significant difference (P correlation coefficient between the young, healthy group and the other two groups. A significant difference (P correlation coefficients in intracranial CSF space among all groups. The result suggests that the CSF space compliance of iNPH patients was lower than that of healthy volunteers. The correlation mapping technique allowed us to visualize pulsatile CSF velocity wave propagations as still images. The technique may help to classify diseases related to CSF dynamics, such as iNPH.

  11. Ultrasound enhanced release of therapeutics from drug-releasing implants based on titania nanotube arrays.

    Science.gov (United States)

    Aw, Moom Sinn; Losic, Dusan

    2013-02-25

    A non-invasive and external stimulus-driven local drug delivery system (DDS) based on titania nanotube (TNT) arrays loaded with drug encapsulated polymeric micelles as drug carriers and ultrasound generator is described. Ultrasound waves (USW) generated by a pulsating sonication probe (Sonotrode) in phosphate buffered saline (PBS) at pH 7.2 as the medium for transmitting pressure waves, were used to release drug-loaded nano-carriers from the TNT arrays. It was demonstrated that a very rapid release in pulsatile mode can be achieved, controlled by several parameters on the ultrasonic generator. This includes pulse length, time, amplitude and power intensity. By optimization of these parameters, an immediate drug-micelles release of 100% that spans a desirable time of 5-50 min was achieved. It was shown that stimulated release can be generated and reproduced at any time throughout the TNT-Ti implant life, suggesting considerable potential of this approach as a feasible and tunable ultrasound-mediated drug delivery system in situ via drug-releasing implants. It is expected that this concept can be translated from an in vitro to in vivo regime for therapeutic applications using drug-releasing implants in orthopedic and coronary stents. Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.

  12. Volatile suppressing method for radioactive iodine

    International Nuclear Information System (INIS)

    Ohara, Atsushi; Haruguchi, Keiko.

    1997-01-01

    In the present invention, a metal plate is disposed above the pool water surface of a suppression chamber disposed to a reactor container in order to reduce evaporation of radioactive iodine released from a suppression pool. A metal plate is disposed above the pool water surface of the suppression chamber disposed to the reactor container. In addition, a metal plate is disposed around the space connecting a bent tube extending from a dry well to underwater of suppression pool water and a gas bent tube extending from the suppression chamber to an emergency gas processing system. Spray water is supplied for cooling the suppression chamber d as a means for cooling the metal plate. Then, among iodine released to the suppression chamber, elemental iodine liberated from the pool water is deposited on the surface of the metal plate, and the amount of iodine to be flown into and processed by an emergency gas processing system or a filter bent system can be reduced. (T.M.)

  13. Arterial stiffness, pressure and flow pulsatility and brain structure and function: the Age, Gene/Environment Susceptibility--Reykjavik study.

    Science.gov (United States)

    Mitchell, Gary F; van Buchem, Mark A; Sigurdsson, Sigurdur; Gotal, John D; Jonsdottir, Maria K; Kjartansson, Ólafur; Garcia, Melissa; Aspelund, Thor; Harris, Tamara B; Gudnason, Vilmundur; Launer, Lenore J

    2011-11-01

    Aortic stiffness increases with age and vascular risk factor exposure and is associated with increased risk for structural and functional abnormalities in the brain. High ambient flow and low impedance are thought to sensitize the cerebral microcirculation to harmful effects of excessive pressure and flow pulsatility. However, haemodynamic mechanisms contributing to structural brain lesions and cognitive impairment in the presence of high aortic stiffness remain unclear. We hypothesized that disproportionate stiffening of the proximal aorta as compared with the carotid arteries reduces wave reflection at this important interface and thereby facilitates transmission of excessive pulsatile energy into the cerebral microcirculation, leading to microvascular damage and impaired function. To assess this hypothesis, we evaluated carotid pressure and flow, carotid-femoral pulse wave velocity, brain magnetic resonance images and cognitive scores in participants in the community-based Age, Gene/Environment Susceptibility--Reykjavik study who had no history of stroke, transient ischaemic attack or dementia (n = 668, 378 females, 69-93 years of age). Aortic characteristic impedance was assessed in a random subset (n = 422) and the reflection coefficient at the aorta-carotid interface was computed. Carotid flow pulsatility index was negatively related to the aorta-carotid reflection coefficient (R = -0.66, Pwave velocity were each associated with increased risk for silent subcortical infarcts (hazard ratios of 1.62-1.71 per standard deviation, Pwave velocity was associated with higher white matter hyperintensity volume (0.108 ± 0.045 SD/SD, P = 0.018). Pulsatility index was associated with lower whole brain (-0.127 ± 0.037 SD/SD, Pwave velocity (-0.095 ± 0.043 SD/SD, P = 0.028) and carotid pulse pressure (-0.114 ± 0.045 SD/SD, P = 0.013) were associated with lower memory scores. Pulsatility index was associated with lower memory scores (-0.165 ± 0.039 SD/SD, Pwave

  14. [Ovulation induction by pulsatile GnRH therapy in 2014: literature review and synthesis of current practice].

    Science.gov (United States)

    Gronier, H; Peigné, M; Catteau-Jonard, S; Dewailly, D; Robin, G

    2014-10-01

    The hypogonadotropic hypogonadism is an easily treatable form of female infertility. The most common cause of hypogonadotropic hypogonadism is functional hypothalamic amenorrhea. The GnRH pump is a simple and effective treatment to restore fertility of patients with hypothalamic amenorrhea: cumulative pregnancy rate is estimated between 70 and 100% after 6 cycles, compared to a low rate of complications and multiple pregnancies. While only 2.8 cycles are on average required to achieve a pregnancy with a pump, this induction of ovulation stays underused in France. The objective of this paper is to propose a practical manual of pulsatile GnRH, in order to improve the accessibility of pulsatile GnRH for patients with hypogonadotropic hypogonadism. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  15. Prediction of low birth weight: the placental T2* estimated by MRI versus the uterine artery pulsatility index

    DEFF Research Database (Denmark)

    Sinding, Marianne Munk; Peters, David Alberg; Frøkjær, Jens Brøndum

    (MRI) variable T2* reflects the placental oxygenation and thereby placental function. Therefore, we aimed to evaluate the performance of placental T2* in the prediction of low birth weight using the uterine artery (UtA) pulsatility index (PI) as gold standard. Methods: The study population......CONTROL ID: 2516296 ABSTRACT FINAL ID: P22.05 TITLE: Prediction of low birth weight: the placental T2* estimated by MRI versus the uterine artery pulsatility index AUTHORS (FIRST NAME, LAST NAME): Marianne Sinding1, David Peters2, Jens B. Frøkjær3, 4, Ole B. Christiansen1, 4, Astrid Petersen5...... had an EFW T2* was measured by MRI at 1.5T. A gradient recalled echo MRI sequence with readout at 16 echo times was used, and the placental T2* value was obtained by fitting the signal intensity as a function of the echo times...

  16. Flow Visualization of Three-Dimensionality Inside the 12 cc Penn State Pulsatile Pediatric Ventricular Assist Device

    OpenAIRE

    Roszelle, Breigh N.; Deutsch, Steven; Manning, Keefe B.

    2010-01-01

    In order to aid the ongoing concern of limited organ availability for pediatric heart transplants, Penn State has continued development of a pulsatile Pediatric Ventricular Assist Device (PVAD). Initial studies of the PVAD observed an increase in thrombus formation due to differences in flow field physics when compared to adult sized devices, which included a higher degree of three-dimensionality. This unique flow field brings into question the use of 2D planar particle image velocimetry (PIV...

  17. Externally controlled triggered-release of drug from PLGA micro and nanoparticles.

    Directory of Open Access Journals (Sweden)

    Xin Hua

    Full Text Available Biofilm infections are extremely hard to eradicate and controlled, triggered and controlled drug release properties may prolong drug release time. In this study, the ability to externally control drug release from micro and nanoparticles was investigated. We prepared micro/nanoparticles containing ciprofloxacin (CIP and magnetic nanoparticles encapsulated in poly (lactic-co-glycolic acid PLGA. Both micro/nanoparticles were observed to have narrow size distributions. We investigated and compared their passive and externally triggered drug release properties based on their different encapsulation structures for the nano and micro systems. In passive release studies, CIP demonstrated a fast rate of release in first 2 days which then slowed and sustained release for approximately 4 weeks. Significantly, magnetic nanoparticles containing systems all showed ability to have triggered drug release when exposed to an external oscillating magnetic field (OMF. An experiment where the OMF was turned on and off also confirmed the ability to control the drug release in a pulsatile manner. The magnetically triggered release resulted in a 2-fold drug release increase compared with normal passive release. To confirm drug integrity following release, the antibacterial activity of released drug was evaluated in Pseudomonas aeruginosa biofilms in vitro. CIP maintained its antimicrobial activity after encapsulation and triggered release.

  18. Externally controlled triggered-release of drug from PLGA micro and nanoparticles.

    Science.gov (United States)

    Hua, Xin; Tan, Shengnan; Bandara, H M H N; Fu, Yujie; Liu, Siguo; Smyth, Hugh D C

    2014-01-01

    Biofilm infections are extremely hard to eradicate and controlled, triggered and controlled drug release properties may prolong drug release time. In this study, the ability to externally control drug release from micro and nanoparticles was investigated. We prepared micro/nanoparticles containing ciprofloxacin (CIP) and magnetic nanoparticles encapsulated in poly (lactic-co-glycolic acid) PLGA. Both micro/nanoparticles were observed to have narrow size distributions. We investigated and compared their passive and externally triggered drug release properties based on their different encapsulation structures for the nano and micro systems. In passive release studies, CIP demonstrated a fast rate of release in first 2 days which then slowed and sustained release for approximately 4 weeks. Significantly, magnetic nanoparticles containing systems all showed ability to have triggered drug release when exposed to an external oscillating magnetic field (OMF). An experiment where the OMF was turned on and off also confirmed the ability to control the drug release in a pulsatile manner. The magnetically triggered release resulted in a 2-fold drug release increase compared with normal passive release. To confirm drug integrity following release, the antibacterial activity of released drug was evaluated in Pseudomonas aeruginosa biofilms in vitro. CIP maintained its antimicrobial activity after encapsulation and triggered release.

  19. Transition to turbulence in pulsatile flow through heart valves--a modified stability approach.

    Science.gov (United States)

    Bluestein, D; Einav, S

    1994-11-01

    The presence of turbulence in the cardiovascular system is generally an indication of some type of abnormality. Most cardiologists agree that turbulence near a valve indicates either valvular stenosis or regurgitation, depending on the phase of its occurrence during the cardiac cycle. As no satisfying analytical solutions of the stability of turbulent pulsatile flow exist, accurate, unbiased flow stability criteria are needed for the identification of turbulence initiation. The traditional approach uses a stability diagram based upon the stability of a plane Stokes layer where alpha (the Womersley parameter) is defined by the fundamental heart rate. We suggest a modified approach that involves the decomposition of alpha into its frequency components, where alpha is derived from the preferred modes induced on the flow by interaction between flow pulsation and the valve. Transition to turbulence in pulsatile flow through heart values was investigated in a pulse duplicator system using three polymer aortic valve models representing a normal aortic valve, a 65 percent stenosed valve and a 90 percent severely stenosed valve, and two mitral valve models representing a normal mitral valve and a 65 percent stenosed valve. Valve characteristics were closely simulated as to mimic the conditions that alter flow stability and initiate turbulent flow conditions. Valvular velocity waveforms were measured by laser Doppler anemometry (LDA). Spectral analysis was performed on velocity signals at selected spatial and temporal points to produce the power density spectra, in which the preferred frequency modes were identified. The spectra obtained during the rapid closure stage of the valves were found to be governed by the stenosis geometry. A shift toward higher dominant frequencies was correlated with the severity of the stenosis. According to the modified approach, stability of the flow is represented by a cluster of points, each corresponding to a specific dominant mode apparent

  20. Reference Curve for the Mean Uterine Artery Pulsatility Index in Singleton Pregnancies.

    Science.gov (United States)

    Weichert, Alexander; Hagen, Andreas; Tchirikov, Michael; Fuchs, Ilka B; Henrich, Wolfgang; Entezami, Michael

    2017-05-01

    Doppler sonography of the uterine artery (UA) is done to monitor pregnancies, because the detected flow patterns are useful to draw inferences about possible disorders of trophoblast invasion. Increased resistance in the UA is associated with an increased risk of preeclampsia and/or intrauterine growth restriction (IUGR) and perinatal mortality. In the absence of standardized figures, the normal ranges of the various available reference curves sometimes differ quite substantially from one another. The causes for this are differences in the flow patterns of the UA depending on the position of the pulsed Doppler gates as well as branching of the UA. Because of the discrepancies between the different reference curves and the practical problems this poses for guideline recommendations, we thought it would be useful to create our own reference curves for Doppler measurements of the UA obtained from a singleton cohort under standardized conditions. This retrospective cohort study was carried out in the Department of Obstetrics of the Charité - Universitätsmedizin Berlin, the Department for Obstetrics and Prenatal Medicine of the University Hospital Halle (Saale) and the Center for Prenatal Diagnostics and Human Genetics Kurfürstendamm 199. Available datasets from the three study locations were identified and reference curves were generated using the LMS method. Measured values were correlated with age of gestation, and a cubic model and Box-Cox power transformation (L), the median (M) and the coefficient of variation (S) were used to smooth the curves. 103 720 Doppler examinations of the UA carried out in singleton pregnancies from the 11th week of gestation (10 + 1 GW) were analyzed. The mean pulsatility index (Mean PI) showed a continuous decline over the course of pregnancy, dropping to a plateau of around 0.84 between the 23rd and 27th GW, after which it decreased again. Age of gestation, placental position, position of pulsed Doppler gates and branching of

  1. Assessment of turbulence models for pulsatile flow inside a heart pump.

    Science.gov (United States)

    Al-Azawy, Mohammed G; Turan, A; Revell, A

    2016-02-01

    Computational fluid dynamics (CFD) is applied to study the unsteady flow inside a pulsatile pump left ventricular assist device, in order to assess the sensitivity to a range of commonly used turbulence models. Levels of strain and wall shear stress are directly relevant to the evaluation of risk from haemolysis and thrombosis, and thus understanding the sensitivity to these turbulence models is important in the assessment of uncertainty in CFD predictions. The study focuses on a positive displacement or pulsatile pump, and the CFD model includes valves and moving pusher plate. An unstructured dynamic layering method was employed to capture this cyclic motion, and valves were simulated in their fully open position to mimic the natural scenario, with in/outflow triggered at control planes away from the valves. Six turbulence models have been used, comprising three relevant to the low Reynolds number nature of this flow and three more intended to investigate different transport effects. In the first group, we consider the shear stress transport (SST) [Formula: see text] model in both its standard and transition-sensitive forms, and the 'laminar' model in which no turbulence model is used. In the second group, we compare the one equation Spalart-Almaras model, the standard two equation [Formula: see text] and the full Reynolds stress model (RSM). Following evaluation of spatial and temporal resolution requirements, results are compared with available experimental data. The model was operated at a systolic duration of 40% of the pumping cycle and a pumping rate of 86 BPM (beats per minute). Contrary to reasonable preconception, the 'transition' model, calibrated to incorporate additional physical modelling specifically for these flow conditions, was not noticeably superior to the standard form of the model. Indeed, observations of turbulent viscosity ratio reveal that the transition model initiates a premature increase of turbulence in this flow, when compared with

  2. Treatment of cellulite with a bipolar radiofrequency, infrared heat, and pulsatile suction device: a pilot study.

    Science.gov (United States)

    Wanitphakdeedecha, Rungsima; Manuskiatti, Woraphong

    2006-12-01

    Very few therapeutic options have proven effective in the treatment of cellulite. To evaluate the effectiveness and adverse effects of a bipolar radiofrequency (RF), infrared (IR) heat and pulsatile suction device for the treatment of cellulite. Twelve subjects were treated with the RF-light-based device. All subjects were treated twice weekly for a total number of eight to nine treatments. Subjects were evaluated using standardized photographs, and measurements of body weight and circumference of treatment sites at baseline, immediately after the last treatment, and four weeks and one year after the last treatment. Clinical improvement scores of comparable photographs using a quartile grading scale (0 = 75% improvement) were judged independently by two non-treating dermatologists after the series of treatment. The average body weights at baseline, immediately after the last treatment, and four weeks and one year after the complete treatment were 56.30, 56.05, 56.23, and 56.53 kg, respectively. The average circumferential reductions of the abdomen and thigh at the last treatment visit were 5.17 +/- 1.04 cm (6.32%+/- 1.82%) and 3.50 +/- 2.16 cm (6.23 +/- 3.58%), respectively. At four weeks after the last treatment, the average circumferential reductions of the abdomen and thigh were sustained at 3.17 +/- 2.75 cm (4.04%+/- 3.69%) and 3.50 +/- 2.04 cm (6.26%+/- 3.52%), respectively. At one year follow-up visit, the average circumferential reductions of the abdomen and thigh were maintained at 3.83 +/- 0.76 cm (4.64%+/- 1.15%) and 3.13 +/- 3.54 (5.50%+/- 6.12%), respectively. Average clinical improvement scores of the abdomen and thigh after the series of treatments were 0.75 (corresponding to approximately 25% improvement), and 1.75 (corresponding to approximately 50% improvement), respectively. A bipolar RF, IR heat and pulsatile suction device provides a beneficial effect on reduction of abdomen and thigh circumference, and smoothening of the cellulite.

  3. EIT based pulsatile impedance monitoring during spontaneous breathing in cystic fibrosis.

    Science.gov (United States)

    Krueger-Ziolek, Sabine; Schullcke, Benjamin; Gong, Bo; Müller-Lisse, Ullrich; Moeller, Knut

    2017-06-01

    Evaluating the lung function in patients with obstructive lung disease by electrical impedance tomography (EIT) usually requires breathing maneuvers containing deep inspirations and forced expirations. Since these maneuvers strongly depend on the patient's co-operation and health status, normal tidal breathing was investigated in an attempt to develop continuous maneuver-free measurements. Ventilation related and pulsatile impedance changes were systematically analyzed during normal tidal breathing in 12 cystic fibrosis (CF) patients and 12 lung-healthy controls (HL). Tidal breaths were subdivided into three inspiratory (In1, In2, In3) and three expiratory (Ex1, Ex2, Ex3) sections of the same amplitude of global impedance change. Maximal changes of the ventilation and the pulsatile impedance signal occurring during these sections were determined (▵I V and ▵I P ). Differences in ▵I V and ▵I P among sections were ascertained in relation to the first inspiratory section. In addition, ▵I V /▵I P was calculated for each section. Medians of changes in ▵I V were  <0.05% in all sections for both subject groups. Both groups showed a similar pattern of ▵I P changes during tidal breathing. Changes in ▵I P first decreased during inspiration (In2), then increased towards the end of inspiration (In3) and reached a maximum at the beginning of expiration (Ex1). During the last two sections of expiration (Ex2, Ex3) ▵I P changes decreased. The CF patients showed higher variations in ▵I P changes compared to the controls (CF:  -426.5%, HL:  -158.1%, coefficient of variation). Furthermore, ▵I V /▵I P significantly differed between expiratory sections for the CF patients (Ex1-Ex2, p  <  0.01; Ex1-Ex3, p  <  0.001; Ex2-Ex3, p  <  0.05), but not for the controls. No significant differences in ▵I V /▵I P between inspiratory sections were determined for both groups. Differences in ▵I P changes and in ▵I V /▵I P between

  4. Neuroanatomical Alterations in Patients with Early Stage of Unilateral Pulsatile Tinnitus: A Voxel-Based Morphometry Study

    Directory of Open Access Journals (Sweden)

    Yawen Liu

    2018-01-01

    Full Text Available During the past several years, the rapid development of neuroimaging techniques has contributed greatly in the noninvasive imaging studies of tinnitus. The aim of the present study was to explore the brain anatomical alterations in patients with right-sided unilateral pulsatile tinnitus (PT in the early stage of PT symptom using voxel-based morphometry (VBM analysis. Twenty-four patients with right-sided pulsatile tinnitus and 24 age- and gender-matched normal controls were recruited to this study. Structural image data preprocessing was performed using VBM8 toolbox. Tinnitus Handicap Inventory (THI score was acquired in the tinnitus group to assess the severity of tinnitus and tinnitus-related distress. Two-sample t-test and Pearson’s correlation analysis were used in statistical analysis. Patients with unilateral pulsatile tinnitus had significantly increased gray matter (GM volume in bilateral superior temporal gyrus compared with the normal controls. However, the left cerebellum posterior lobe, left frontal superior orbital lobe (gyrus rectus, right middle occipital gyrus (MOG, and bilateral putamen showed significantly decreased brain volumes. This was the first study which demonstrated the features of neuroanatomical changes in patients with unilateral PT during their early stages of the symptom.

  5. Local pulsatile contractions are an intrinsic property of the myosin 2A motor in the cortical cytoskeleton of adherent cells.

    Science.gov (United States)

    Baird, Michelle A; Billington, Neil; Wang, Aibing; Adelstein, Robert S; Sellers, James R; Fischer, Robert S; Waterman, Clare M

    2017-01-15

    The role of nonmuscle myosin 2 (NM2) pulsatile dynamics in generating contractile forces required for developmental morphogenesis has been characterized, but whether these pulsatile contractions are an intrinsic property of all actomyosin networks is not known. Here we used live-cell fluorescence imaging to show that transient, local assembly of NM2A "pulses" occurs in the cortical cytoskeleton of single adherent cells of mesenchymal, epithelial, and sarcoma origin, independent of developmental signaling cues and cell-cell or cell-ECM interactions. We show that pulses in the cortical cytoskeleton require Rho-associated kinase- or myosin light chain kinase (MLCK) activity, increases in cytosolic calcium, and NM2 ATPase activity. Surprisingly, we find that cortical cytoskeleton pulses specifically require the head domain of NM2A, as they do not occur with either NM2B or a 2B-head-2A-tail chimera. Our results thus suggest that pulsatile contractions in the cortical cytoskeleton are an intrinsic property of the NM2A motor that may mediate its role in homeostatic maintenance of tension in the cortical cytoskeleton of adherent cells. © 2017 Baird et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  6. Long-Term Durability Test for the Left Ventricular Assist System EVAHEART under the Physiologic Pulsatile Load.

    Science.gov (United States)

    Kitano, Tomoya; Iwasaki, Kiyotaka

    The EVAHEART Left Ventricular Assist System (LVAS) was designed for the long-term support of a patient with severe heart failure. It has an original water lubrication system for seal and bearing and wear on these parts was considered one of its critical failure modes. A durability test focusing on wear was designed herein. We developed a mock loop, which generates a physiologic pulsatile flow and is sufficiently durable for a long-term test. The pulsatile load and the low fluid viscosity enable the creation of a severe condition for the mechanical seal. A total of 18 EVAHEART blood pumps completed 2 years of operation under the pulsatile condition without any failure. It indicated the EVAHEART blood pump had a greater than 90% reliability with a 88% confidence level. The test was continued with six blood pumps and achieved an average of 8.6 years, which was longer than the longest clinical use in Japan. The test result showed that no catastrophic, critical, marginal, or minor failures of the blood pump or their symptoms were observed. The seal performance was maintained after the test. Moreover, the surface roughness did not change, which showed any burn or abnormal wear occurred. The original water lubrication system equipped in EVAHEART LVAS prevent severe wear on the seal and the bearing, and it can be used in the bridge to transplant and destination therapy.

  7. Secondary flow vortical structures in a 180∘ elastic curved vessel with torsion under steady and pulsatile inflow conditions

    Science.gov (United States)

    Najjari, Mohammad Reza; Plesniak, Michael W.

    2018-01-01

    Secondary flow structures in a 180∘ curved pipe model of an artery are studied using particle image velocimetry. Both steady and pulsatile inflow conditions are investigated. In planar curved pipes with steady flow, multiple (two, four, six) vortices are detected. For pulsatile flow, various pairs of vortices, i.e., Dean, deformed-Dean, Lyne-type, and split-Dean, are present in the cross section of the pipe at 90∘ into the bend. The effects of nonplanar curvature (torsion) and vessel dilatation on these vortical structures are studied. Torsion distorts the symmetric secondary flows (which exist in planar curvatures) and can result in formation of more complex vortical structures. For example, the split-Dean and Lyne-type vortices with same rotation direction originating from opposite sides of the cross section tend to merge together in pulsatile flow. The vortical structures in elastic vessels with dilatation (0.61%-3.23%) are also investigated and the results are compared with rigid model results. It was found that the secondary flow structures in rigid and elastic models are similar, and hence the local compliance of the vessel does not affect the morphology of secondary flow structures.

  8. Dexamethasone suppression test

    Science.gov (United States)

    DST; ACTH suppression test; Cortisol suppression test ... During this test, you will receive dexamethasone. This is a strong man-made (synthetic) glucocorticoid medicine. Afterward, your blood is drawn ...

  9. Deconstructing continuous flash suppression

    OpenAIRE

    Yang, Eunice; Blake, Randolph

    2012-01-01

    In this paper, we asked to what extent the depth of interocular suppression engendered by continuous flash suppression (CFS) varies depending on spatiotemporal properties of the suppressed stimulus and CFS suppressor. An answer to this question could have implications for interpreting the results in which CFS influences the processing of different categories of stimuli to different extents. In a series of experiments, we measured the selectivity and depth of suppression (i.e., elevation in co...

  10. Nonlinear dynamics of shells conveying pulsatile flow with pulse-wave propagation. Theory and numerical results for a single harmonic pulsation

    Science.gov (United States)

    Tubaldi, Eleonora; Amabili, Marco; Païdoussis, Michael P.

    2017-05-01

    In deformable shells conveying pulsatile flow, oscillatory pressure changes cause local movements of the fluid and deformation of the shell wall, which propagate downstream in the form of a wave. In biomechanics, it is the propagation of the pulse that determines the pressure gradient during the flow at every location of the arterial tree. In this study, a woven Dacron aortic prosthesis is modelled as an orthotropic circular cylindrical shell described by means of the Novozhilov nonlinear shell theory. Flexible boundary conditions are considered to simulate connection with the remaining tissue. Nonlinear vibrations of the shell conveying pulsatile flow and subjected to pulsatile pressure are investigated taking into account the effects of the pulse-wave propagation. For the first time in literature, coupled fluid-structure Lagrange equations of motion for a non-material volume with wave propagation in case of pulsatile flow are developed. The fluid is modeled as a Newtonian inviscid pulsatile flow and it is formulated using a hybrid model based on the linear potential flow theory and considering the unsteady viscous effects obtained from the unsteady time-averaged Navier-Stokes equations. Contributions of pressure and velocity propagation are also considered in the pressure drop along the shell and in the pulsatile frictional traction on the internal wall in the axial direction. A numerical bifurcation analysis employs a refined reduced order model to investigate the dynamic behavior of a pressurized Dacron aortic graft conveying blood flow. A pulsatile time-dependent blood flow model is considered by applying the first harmonic of the physiological waveforms of velocity and pressure during the heart beating period. Geometrically nonlinear vibration response to pulsatile flow and transmural pulsatile pressure, considering the propagation of pressure and velocity changes inside the shell, is here presented via frequency-response curves, time histories, bifurcation

  11. A Novel Pulsatile Bioreactor for Mechanical Stimulation of Tissue Engineered Cardiac Constructs

    Directory of Open Access Journals (Sweden)

    Günther Eissner

    2011-07-01

    Full Text Available After myocardial infarction, the implantation of stem cell seeded scaffolds on the ischemic zone represents a promising strategy for restoration of heart function. However, mechanical integrity and functionality of tissue engineered constructs need to be determined prior to implantation. Therefore, in this study a novel pulsatile bioreactor mimicking the myocardial contraction was developed to analyze the behavior of mesenchymal stem cells derived from umbilical cord tissue (UCMSC colonized on titanium-coated polytetrafluorethylene scaffolds to friction stress. The design of the bioreactor enables a simple handling and defined mechanical forces on three seeded scaffolds at physiological conditions. The compact system made of acrylic glass, Teflon®, silicone, and stainless steel allows the comparison of different media, cells and scaffolds. The bioreactor can be gas sterilized and actuated in a standard incubator. Macroscopic observations and pressure-measurements showed a uniformly sinusoidal pulsation, indicating that the bioreactor performed well. Preliminary experiments to determine the adherence rate and morphology of UCMSC after mechanical loadings showed an almost confluent cellular coating without damage on the cell surface. In summary, the bioreactor is an adequate tool for the mechanical stress of seeded scaffolds and offers dynamic stimuli for pre-conditioning of cardiac tissue engineered constructs in vitro.

  12. Numerical investigation of flow parameters for solid rigid spheroidal particle in a pulsatile pipe flow

    Science.gov (United States)

    Varghese, Joffin; Jayakumar, J. S.

    2017-09-01

    Quantifying, forecasting and analysing the displacement rates of suspended particles are essential while discussing about blood flow analysis. Because blood is one of the major organs in the body, which enables transport phenomena, comprising of numerous blood cells. In order to model the blood flow, a flow domain was created and numerically simulated. Flow field velocity in the stream is solved utilizing Finite Volume Method utilizing FVM unstructured solver. In pulsatile flow, the effect of parameters such as average Reynolds number, tube radius, particle size and Womersley number are taken into account. In this study spheroidal particle trajectory in axial direction is simulated at different values of pulsating frequency including 1.2 Hz, 3.33 Hz and 4.00 Hz and various densities including 1005 kg/m3 and 1025 kg/m3 for the flow domain. The analysis accomplishes the interaction study of blood constituents for different flow situations which have applications in diagnosis and treatment of cardio vascular related diseases.

  13. Cerebral Pulsatility Index Is Elevated in Patients with Elevated Right Atrial Pressure.

    Science.gov (United States)

    Lahiri, Shouri; Schlick, Konrad H; Padrick, Matthew M; Rinsky, Brenda; Gonzalez, Nestor; Jones, Heather; Mayer, Stephan A; Lyden, Patrick D

    2018-01-01

    Extracerebral venous congestion can precipitate intracranial hypertension due to obstruction of cerebral blood outflow. Conditions that increase right atrial pressure, such as hypervolemia, are thought to increase resistance to jugular venous outflow and contribute to cerebro-venous congestion. Cerebral pulsatility index (CPI) is considered a surrogate marker of distal cerebrovascular resistance and is elevated with intracranial hypertension. Thus, we sought to test the hypothesis that elevated right atrial pressure is associated with increased CPI compared to normal right atrial pressure. We retrospectively reviewed 61 consecutive patients with subarachnoid hemorrhage. We calculated CPI from transcranial Doppler studies and correlated these with echocardiographic measures of right atrial pressure. CPIs were compared from patients with elevated and normal right atrial pressure. There was a significant difference between CPI obtained from all patients with elevated right atrial pressure compared to those with normal right atrial pressure (P right and left hemispheric CPI from patients with both elevated and normal right atrial pressure. Patients with elevated right atrial pressure had significantly higher CPI compared to patients with normal right atrial pressure. These findings suggest that cerebro-venous congestion due to impaired jugular venous outflow may increase distal cerebrovascular resistance as measured by CPI. Since elevated CPI is associated with poor outcome in numerous neurological conditions, future studies are needed to elucidate the significance of these results in other populations. Copyright © 2017 by the American Society of Neuroimaging.

  14. Mathematical Modeling of Rotary Blood Pumps in a Pulsatile In Vitro Flow Environment.

    Science.gov (United States)

    Pirbodaghi, Tohid

    2017-08-01

    Nowadays, sacrificing animals to develop medical devices and receive regulatory approval has become more common, which increases ethical concerns. Although in vivo tests are necessary for development and evaluation of new devices, nonetheless, with appropriate in vitro setups and mathematical models, a part of the validation process can be performed using these models to reduce the number of sacrificed animals. The main aim of this study is to present a mathematical model simulating the hydrodynamic function of a rotary blood pump (RBP) in a pulsatile in vitro flow environment. This model relates the pressure head of the RBP to the flow rate, rotational speed, and time derivatives of flow rate and rotational speed. To identify the model parameters, an in vitro setup was constructed consisting of a piston pump, a compliance chamber, a throttle, a buffer reservoir, and the CentriMag RBP. A 40% glycerin-water mixture as a blood analog fluid and deionized water were used in the hydraulic circuit to investigate the effect of viscosity and density of the working fluid on the model parameters. First, model variables were physically measured and digitally acquired. Second, an identification algorithm based on regression analysis was used to derive the model parameters. Third, the completed model was validated with a totally different set of in vitro data. The model is usable for both mathematical simulations of the interaction between the pump and heart and indirect pressure measurement in a clinical context. © 2017 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  15. Obesity, serum steroid levels, and pulsatile gonadotropin secretion in polycystic ovarian disease.

    Science.gov (United States)

    Laatikainen, T; Tulenheimo, A; Andersson, B; Kärkkäinen, J

    1983-04-01

    Serum binding capacity of sex-hormone binding globulin (SHBG-BC), steroid concentrations, and secretion patterns of LH and FSH were compared between groups of seven nonobese and seven obese patients with polycystic ovarian disease (PCOD). Obese patients with PCOD differed from those with normal weight in having very low SHBG-BC and elevated serum levels of free and albumin bound testosterone. Compared to healthy women in the follicular phase, both nonobese and obese patients with PCOD showed equally elevated serum levels of androstenedione, estrone, and albumin-bound and free estradiol. Pattern of gonadotropin secretion was studied from blood samples taken at 15 min intervals for 6 h. In 6 patients of both groups low pulses of FSH were found coincidently with pulses of LH. Serum level of LH showed a clear pulsatile pattern in all patients with PCOD, varying from 4.5 to 7.5 pulses per 6 h. The mean pulse rate in the groups of nonobese and obese patients with PCOD was similar, 5.9 pulses per 6 h. In the obese patients the mean LH levels were, however, less elevated and the pulse amplitudes were smaller than those in the nonobese patients. We suggest that this difference is due to high levels of biologically active testosterone in obese patients with PCOD.

  16. Pulsatile Flow and Transport of Blood past a Cylinder: Basic Transport for an Artificial Lung.

    Science.gov (United States)

    Zierenberg, Jennifer R.

    2005-11-01

    The fluid mechanics and transport for flow of blood past a single cylinder is investigated using CFD. This work refers to an artificial lung in which oxygen travels through fibers oriented perpendicularly to the incoming blood flow. A pulsatile blood flow was considered: Ux=U0[ 1+A( φt ) ], where Ux is the velocity far from the cylinder. The Casson equation was used to describe the shear thinning and yield stress properties of blood. The presence of hemoglobin (i.e. facilitated diffusion) was considered. We examined the effect of A, U0 and φ on the flow and transport by varying the dimensionless parameters: A; Reynolds number, Re; and Womersley parameter, α. Two different feed gases were considered: pure O2 and air. The flow and concentration fields were computed for Re = 5, 10, and 40, 0 transport is found to primarily depend on Re and to increase with increasing Re, α and decreasing A. The presence of hemoglobin increases mass transport. Supported by NIH HL69420, NSF Fellowship

  17. A study of the pulsatile flow and its interaction with rectangular leaflets

    Science.gov (United States)

    Ledesma, Rene; Zenit, Roberto; Pulos, Guillermo

    2009-11-01

    To avoid the complexity and limited understanding of the 3D pulsatile flow field through heart valves, a cardiac-like flow circuit and a test channel were designed to study the behavior of bidimensional leaflets made of hyperelastic materials. We study a simple 2D arrangement to understand the basic physics of the flow-leaflet interaction. Creating a periodic pressure gradient, measurements of leaflet deflection were obtained for different flow conditions, geometries and materials. Using PIV and Phase Locking techniques, we have obtained the leaflet motion and the time-dependent flow velocity fields. The results show that two dimensionless parameters determine the performance of a simple bi-dimensional valve, in accordance with the flow conditions applied: π1=f(sw)^1/2(E/ρ)^1/2 and π2=V/(2slw), where f is the pulsation frequency, V is the stroke volume, s, w and l are the dimensions on the leaftlet and E and ρ are the elastic modulus and density of the material, respectively. Furthermore, we have identified the conditions for which the fluid stresses can be minimized. With these results we propose a new set of parameters to improve the performance of prosthetic heart valves and, in consequence, to reduce blood damage.

  18. Bioavailability assessment of hydroxymethylglutaryl coenzyme A reductase inhibitor utilizing pulsatile drug delivery system: a pilot study.

    Science.gov (United States)

    Taha, Ehab I

    2016-09-01

    Chronotherapy or pulsatile drug delivery system could be achieved by increasing drug plasma concentration exactly at the time of disease incidence. Cholesterol synthesis shows a circadian rhythm being high at late night and early in the morning. Simvastatin (SIM) inhibits hydroxymethylglutaryl coenzyme A reductase, which is responsible for cholesterol synthesis. In this study, SIM lipid-based formulation filled in gelatin capsules and coated with aqueous Eudragit® S100 dispersion was prepared for chronotherapeutic treatment of hypercholesterolemia. The pharmacokinetic parameters of SIM capsules were studied in human volunteers after a single oral dose and compared with that of Zocor® tablets as a reference in a randomized cross-over study. Pharmacokinetic parameters such as AUC 0-∞ , C max , T max , t 1/2 and elimination rate constant were determined from plasma concentration-time profile for both formulations. The tested formulation had the ability to delay drug absorption and provide higher drug concentrations from 3 up to 10 h after oral administration compared to that of commercial tablets. The data in this study revealed that the prepared formulation could be effective in chronotherapeutic treatment of hypercholesterolemia. Moreover, the tested formulation was found to enhance SIM bioavailability by 29% over the reference tablets.

  19. Pulsatility Index as a Diagnostic Parameter of Reciprocating Wall Shear Stress Parameters in Physiological Pulsating Waveforms.

    Directory of Open Access Journals (Sweden)

    Idit Avrahami

    Full Text Available Arterial wall shear stress (WSS parameters are widely used for prediction of the initiation and development of atherosclerosis and arterial pathologies. Traditional clinical evaluation of arterial condition relies on correlations of WSS parameters with average flow rate (Q and heart rate (HR measurements. We show that for pulsating flow waveforms in a straight tube with flow reversals that lead to significant reciprocating WSS, the measurements of HR and Q are not sufficient for prediction of WSS parameters. Therefore, we suggest adding a third quantity-known as the pulsatility index (PI-which is defined as the peak-to-peak flow rate amplitude normalized by Q. We examine several pulsating flow waveforms with and without flow reversals using a simulation of a Womersley model in a straight rigid tube and validate the simulations through experimental study using particle image velocimetry (PIV. The results indicate that clinically relevant WSS parameters such as the percentage of negative WSS (P[%], oscillating shear index (OSI and the ratio of minimum to maximum shear stress rates (min/max, are better predicted when the PI is used in conjunction with HR and Q. Therefore, we propose to use PI as an additional and essential diagnostic quantity for improved predictability of the reciprocating WSS.

  20. Dynamic time warping and machine learning for signal quality assessment of pulsatile signals

    International Nuclear Information System (INIS)

    Li, Q; Clifford, G D

    2012-01-01

    In this work, we describe a beat-by-beat method for assessing the clinical utility of pulsatile waveforms, primarily recorded from cardiovascular blood volume or pressure changes, concentrating on the photoplethysmogram (PPG). Physiological blood flow is nonstationary, with pulses changing in height, width and morphology due to changes in heart rate, cardiac output, sensor type and hardware or software pre-processing requirements. Moreover, considerable inter-individual and sensor-location variability exists. Simple template matching methods are therefore inappropriate, and a patient-specific adaptive initialization is therefore required. We introduce dynamic time warping to stretch each beat to match a running template and combine it with several other features related to signal quality, including correlation and the percentage of the beat that appeared to be clipped. The features were then presented to a multi-layer perceptron neural network to learn the relationships between the parameters in the presence of good- and bad-quality pulses. An expert-labeled database of 1055 segments of PPG, each 6 s long, recorded from 104 separate critical care admissions during both normal and verified arrhythmic events, was used to train and test our algorithms. An accuracy of 97.5% on the training set and 95.2% on test set was found. The algorithm could be deployed as a stand-alone signal quality assessment algorithm for vetting the clinical utility of PPG traces or any similar quasi-periodic signal. (paper)

  1. Dynamic time warping and machine learning for signal quality assessment of pulsatile signals.

    Science.gov (United States)

    Li, Q; Clifford, G D

    2012-09-01

    In this work, we describe a beat-by-beat method for assessing the clinical utility of pulsatile waveforms, primarily recorded from cardiovascular blood volume or pressure changes, concentrating on the photoplethysmogram (PPG). Physiological blood flow is nonstationary, with pulses changing in height, width and morphology due to changes in heart rate, cardiac output, sensor type and hardware or software pre-processing requirements. Moreover, considerable inter-individual and sensor-location variability exists. Simple template matching methods are therefore inappropriate, and a patient-specific adaptive initialization is therefore required. We introduce dynamic time warping to stretch each beat to match a running template and combine it with several other features related to signal quality, including correlation and the percentage of the beat that appeared to be clipped. The features were then presented to a multi-layer perceptron neural network to learn the relationships between the parameters in the presence of good- and bad-quality pulses. An expert-labeled database of 1055 segments of PPG, each 6 s long, recorded from 104 separate critical care admissions during both normal and verified arrhythmic events, was used to train and test our algorithms. An accuracy of 97.5% on the training set and 95.2% on test set was found. The algorithm could be deployed as a stand-alone signal quality assessment algorithm for vetting the clinical utility of PPG traces or any similar quasi-periodic signal.

  2. Computational Fluid Dynamics Analysis of Pulsatile Blood Flow Behavior in Modelled Stenosed Vessels with Different Severities

    Directory of Open Access Journals (Sweden)

    Mohsen Mehrabi

    2012-01-01

    Full Text Available This study focuses on the behavior of blood flow in the stenosed vessels. Blood is modelled as an incompressible non-Newtonian fluid which is based on the power law viscosity model. A numerical technique based on the finite difference method is developed to simulate the blood flow taking into account the transient periodic behaviour of the blood flow in cardiac cycles. Also, pulsatile blood flow in the stenosed vessel is based on the Womersley model, and fluid flow in the lumen region is governed by the continuity equation and the Navier-Stokes equations. In this study, the stenosis shape is cosine by using Tu and Devil model. Comparing the results obtained from three stenosed vessels with 30%, 50%, and 75% area severity, we find that higher percent-area severity of stenosis leads to higher extrapressure jumps and higher blood speeds around the stenosis site. Also, we observe that the size of the stenosis in stenosed vessels does influence the blood flow. A little change on the cross-sectional value makes vast change on the blood flow rate. This simulation helps the people working in the field of physiological fluid dynamics as well as the medical practitioners.

  3. The Relationship Between Pulsatile Flow Impingement and Intraluminal Thrombus Deposition in Abdominal Aortic Aneurysms.

    Science.gov (United States)

    Lozowy, Richard J; Kuhn, David C S; Ducas, Annie A; Boyd, April J

    2017-03-01

    Direct numerical simulations were performed on four patient-specific abdominal aortic aneurysm (AAA) geometries and the resulting pulsatile blood flow dynamics were compared to aneurysm shape and correlated with intraluminal thrombus (ILT) deposition. For three of the cases, turbulent vortex structures impinged/sheared along the anterior wall and along the posterior wall a zone of recirculating blood formed. Within the impingement region the AAA wall was devoid of ILT and remote to this region there was an accumulation of ILT. The high wall shear stress (WSS) caused by the impact of vortexes is thought to prevent the attachment of ILT. WSS from impingement is comparable to peak-systolic WSS in a normal-sized aorta and therefore may not damage the wall. Expansion occurred to a greater extent in the direction of jet impingement and the wall-normal force from the continuous impact of vortexes may contribute to expansion. It was shown that the impingement region has low oscillatory shear index (OSI) and recirculation zones can have either low or high OSI. No correlation could be identified between OSI and ILT deposition since different flow dynamics can have similar OSI values.

  4. On the Evolution of Pulsatile Flow Subject to a Transverse Impulse Body Force

    Science.gov (United States)

    di Labbio, Giuseppe; Keshavarz-Motamed, Zahra; Kadem, Lyes

    2014-11-01

    In the event of an unexpected abrupt traffic stop or car accident, automotive passengers will experience an abrupt body deceleration. This may lead to tearing or dissection of the aortic wall known as Blunt Traumatic Aortic Rupture (BTAR). BTAR is the second leading cause of death in automotive accidents and, although quite frequent, the mechanisms leading to BTAR are still not clearly identified, particularly the contribution of the flow field. As such, this work is intended to provide a fundamental framework for the investigation of the flow contribution to BTAR. In this fundamental study, pulsatile flow in a three-dimensional, straight pipe of circular cross-section is subjected to a unidirectional, transverse, impulse body force applied on a strictly bounded volume of fluid. These models were simulated using the Computational Fluid Dynamics (CFD) software FLUENT. The evolution of fluid field characteristics was investigated during and after the application of the force. The application of the force significantly modified the flow field. The force induces a transverse pressure gradient causing the development of secondary flow structures that dissipate the energy added by the acceleration. Once the force ceases to act, these structures are carried downstream and gradually dissipate their excess energy.

  5. Impedance cardiography: Pulsatile blood flow and the biophysical and electrodynamic basis for the stroke volume equations

    Directory of Open Access Journals (Sweden)

    Donald P Bernstein

    2010-01-01

    Full Text Available Impedance cardiography (ICG is a branch of bioimpedance pimarily concerned with the determination of left ventricular stroke volume (SV. As implemented, using the transthoracic approach, the technique involves applying a current field longitudinally across a segment of thorax by means of a constant magnitude, high frequency, low amplitude alternating current (AC. By Ohm's Law, the voltage difference measured within the current field is proportional to the electrical impedance Z (Ω. Without ventilatory or cardiac activity, Z is known as the transthoracic, static base impedance Z0. Upon ventricular ejection, a characteristic time dependent cardiac-synchronous pulsatile impedance change is obtained, ΔZ(t, which, when placed electrically in parallel with Z0, constitutes the time-variable total transthoracic impedance Z(t. ΔZ(t represents a dual-element composite waveform, which comprises both the radially-oriented volumetric expansion of and axially-directed forward blood flow within both great thoracic arteries. In its majority, however, ΔZ(t is known to primarily emanate from the ascending aorta. Conceptually, commonly implemented methods assume a volumetric origin for the peak systolic upslope of ΔZ(t, (i.e. dZ/dtmax, with the presumed units of Ω·s-1. A recently introduced method assumes the rapid ejection of forward flowing blood in earliest systole causes significant changes in the velocity-induced blood resistivity variation (Δρb(t, Ωcm·s-1, and it is the peak rate of change of the blood resistivity variation dρb(t/dtmax (Ωcm·s-2 that is the origin of dZ/dtmax. As a consequence of dZ/dtmax peaking in the time domain of peak aortic blood acceleration, dv/dtmax (cm·s-2, it is suggested that dZ/dtmax is an ohmic mean acceleration analog (Ω·s-2 and not a mean flow or velocity surrogate as generally assumed. As conceptualized, the normalized value, dZ/dtmax/Z0, is a dimensionless ohmic mean acceleration equivalent (s-2

  6. Development of self-assembled molecular structures on polymeric surfaces and their applications as ultrasonically responsive barrier coatings for on-demand, pulsatile drug delivery

    Science.gov (United States)

    Kwok, Connie Sau-Kuen

    Nature in the form of DNA, proteins, and cells has the remarkable ability to interact with its environment by processing biological information through specific molecular recognition at the interface. As such, materials that are capable of triggering an appropriate biological response need to be engineered at the biomaterial surface. Chemically and structurally well-defined self-assembled monolayers (SAMs), biomimetics of the lipid bilayer in cell membranes, have been created and studied mostly on rigid metallic surfaces. This dissertation is motivated by the lack of methods to generate a molecularly designed surface for biomedical polymers and thus provides an enabling technology to engineer a polymeric surface precisely at a molecular and cellular level. To take this innovation one step further, we demonstrated that such self-assembled molecular structure coated on drug-containing polymeric devices could act as a stimulus-responsive barrier for controlled drug delivery. A simple, one-step procedure for generating ordered, crystalline methylene chains on polymeric surfaces via urethane linkages was successfully developed. The self-assemblies and molecular structures of these crystalline methylene chains are comparable to the SAM model surfaces, as evidenced by various surface characterization techniques (XPS, TOF-SIMS, and FTIR-ATR). For the first time, these self-assembled molecular structures are shown to function collectively as an ultrasound-responsive barrier membrane for pulsatile drug delivery, including delivery of low-molecular-weight ciprofloxacin and high-molecular-weight insulin. Encouraging results, based on the insulin-activated deoxyglucose uptakes in adipocytes, indicate that the released insulin remained biologically active. Both chemical and acoustic analyses suggest that the ultrasound-assisted release mechanism is primarily induced by transient cavitation, which causes temporary disruption of the self-assembled overlayer, and thus allows

  7. Increased pulsatility index supports diagnosis of vascular parkinsonism versus idiopathic Parkinson's disease.

    Science.gov (United States)

    Caba, L M; Ferrairó, J I T; Torres, I M; Costa, J F V; Muñoz, R B; Martin, A L

    2017-12-29

    The diagnosis of vascular parkinsonism (VP) is based on a series of clinical criteria and neuroimaging findings. An increase in transcranial Doppler ultrasonography pulsatility index (PI) has been described as a frequent finding in patients with VP. We aimed to confirm this association and to determine the PI value with the highest sensitivity and specificity for diagnosis of VP. PI was determined in all patients admitted to Hospital Universitari i Politècnic La Fe due to parkinsonism between January 2012 and June 2016. We assessed the probability of having VP based on PI values in patients with a definite diagnosis of either VP or idiopathic Parkinson's disease (IPD). A ROC curve was created to determine the PI value with the highest sensitivity and specificity. We assessed a total of 146 patients with suspected parkinsonism; 54 (37%) were diagnosed with IPD and 15 (10%) with VP. Patients with VP were significantly older than those with IPD (mean age of 79 vs 68.5, P=.00144) and had a higher PI (median of 1.29 [IQR: 1.09-1.38] vs 0.96 [IQR: 0.89-1.16], P=.01328). In our sample, a PI of 1.09 conferred 84% sensitivity and 70% specificity. In our series, the PI was significantly higher in patients with VP than in those with IPD. We therefore support the use of transcranial Doppler ultrasonography for the initial assessment of elderly patients with akinetic-rigid syndrome. Copyright © 2017 Sociedad Española de Neurología. Publicado por Elsevier España, S.L.U. All rights reserved.

  8. Contact-Free Screening of Atrial Fibrillation by a Smartphone Using Facial Pulsatile Photoplethysmographic Signals.

    Science.gov (United States)

    Yan, Bryan P; Lai, William H S; Chan, Christy K Y; Chan, Stephen Chun-Hin; Chan, Lok-Hei; Lam, Ka-Ming; Lau, Ho-Wang; Ng, Chak-Ming; Tai, Lok-Yin; Yip, Kin-Wai; To, Olivia T L; Freedman, Ben; Poh, Yukkee C; Poh, Ming-Zher

    2018-04-05

    We aimed to evaluate a novel method of atrial fibrillation (AF) screening using an iPhone camera to detect and analyze photoplethysmographic signals from the face without physical contact by extracting subtle beat-to-beat variations of skin color that reflect the cardiac pulsatile signal. Patients admitted to the cardiology ward of the hospital for clinical reasons were recruited. Simultaneous facial and fingertip photoplethysmographic measurements were obtained from 217 hospital inpatients (mean age, 70.3±13.9 years; 71.4% men) facing the front camera and with an index finger covering the back camera of 2 independent iPhones before a 12-lead ECG was recorded. Backdrop and background light intensity was monitored during signal acquisition. Three successive 20-second (total, 60 seconds) recordings were acquired per patient and analyzed for heart rate regularity by Cardiio Rhythm (Cardiio Inc, Cambridge, MA) smartphone application. Pulse irregularity in ≥1 photoplethysmographic readings or 3 uninterpretable photoplethysmographic readings were considered a positive AF screening result. AF was present on 12-lead ECG in 34.6% (n=75/217) patients. The Cardiio Rhythm facial photoplethysmographic application demonstrated high sensitivity (95%; 95% confidence interval, 87%-98%) and specificity (96%; 95% confidence interval, 91%-98%) in discriminating AF from sinus rhythm compared with 12-lead ECG. The positive and negative predictive values were 92% (95% confidence interval, 84%-96%) and 97% (95% confidence interval, 93%-99%), respectively. Detection of a facial photoplethysmographic signal to determine pulse irregularity attributable to AF is feasible. The Cardiio Rhythm smartphone application showed high sensitivity and specificity, with low negative likelihood ratio for AF from facial photoplethysmographic signals. The convenience of a contact-free approach is attractive for community screening and has the potential to be useful for distant AF screening. © 2018 The

  9. Sigmoid sinus diverticulum and pulsatile tinnitus - Analysis of CT scans from 15 cases

    International Nuclear Information System (INIS)

    Liu, Zhaohui; Wang, Zhenchang; Xian, Junfang; Wang, Yongzhe; Liang, Xihong; Chen, Chengfang; Gong, Shusheng; Ma, Xiaobo; Li, Yi

    2013-01-01

    Background: Although the imaging features of sigmoid sinus diverticulum induced pulsatile tinnitus (PT) have been presented in some extent, detailed imaging findings still have not been systematically evaluated and precise diagnostic radiographic criteria has not been established. Purpose: To examine the computed tomography (CT) characteristics of sigmoid sinus diverticulum accompanied with PT. Material and Methods: Fifteen PT patients with sigmoid sinus diverticula proven by surgery were recruited after consenting. CT images of 15 patients were obtained and analyzed, including features of diverticula, brain venous systems, integrity of the sigmoid plate, and the degree of temporal bone pneumatization. Results: Sigmoid sinus diverticulum was located on the same side of PT in 15 patients. Diverticula originated at the superior curve of the sigmoid sinus in 11 patients and the descending segment of the sigmoid sinus in four patients. Sigmoid sinus diverticula focally eroded into the adjacent mastoid air cells in 12 patients and mastoid cortex in three patients. Among eight patients with unilateral dominant brain venous systems, the diverticula were seen on the dominant side in seven patients and non-dominant side in one patient. In contrast, the other seven patients showed co-dominant brain venous systems, with three presenting diverticula on the right side and four on the left. More notably, dehiscent sigmoid plate on the PT side was demonstrated in all patients. In addition, temporal bone hyper-pneumatization was found in nine patients, good and moderate pneumatization in three patients, respectively. Conclusion: Dehiscent sigmoid plate and extensive temporal bone pneumatization are two important imaging characteristics of the PT induced by sigmoid sinus diverticulum

  10. The Use of Fluid Mechanics to Predict Regions of Microscopic Thrombus Formation in Pulsatile VADs.

    Science.gov (United States)

    Topper, Stephen R; Navitsky, Michael A; Medvitz, Richard B; Paterson, Eric G; Siedlecki, Christopher A; Slattery, Margaret J; Deutsch, Steven; Rosenberg, Gerson; Manning, Keefe B

    2014-03-01

    We compare the velocity and shear obtained from particle image velocimetry (PIV) and computational fluid dynamics (CFD) in a pulsatile ventricular assist device (VAD) to further test our thrombus predictive methodology using microscopy data from an explanted VAD. To mimic physiological conditions in vitro , a mock circulatory loop is used with a blood analog that matched blood's viscoelastic behavior at 40% hematocrit. Under normal physiologic pressures and for a heart rate of 75 bpm, PIV data is acquired and wall shear maps are produced. The resolution of the PIV shear rate calculations are tested using the CFD and found to be in the same range. A bovine study, using a model of the 50 cc Penn State V-2 VAD, for 30 days at a constant beat rate of 75 beats per minute (bpm) provides the microscopic data whereby after the 30 days, the device is explanted and the sac surface analyzed using scanning electron microscopy (SEM) and, after immunofluorescent labeling for platelets and fibrin, confocal microscopy. Areas are examined based on PIV measurements and CFD, with special attention to low shear regions where platelet and fibrin deposition are most likely to occur. Data collected within the outlet port in a direction normal to the front wall of the VAD shows that some regions experience wall shear rates less than 500 s -1 , which increases the likelihood of platelet and fibrin deposition. Despite only one animal study, correlations between PIV, CFD, and in vivo data show promise. Deposition probability is quantified by the thrombus susceptibility potential, a calculation to correlate low shear and time of shear with deposition.

  11. Pulsatility index variations using two different transit-time flowmeters in coronary artery bypass surgery.

    Science.gov (United States)

    Nordgaard, Håvard B; Vitale, Nicola; Astudillo, Rafael; Renzulli, Attilio; Romundstad, Pål; Haaverstad, Rune

    2010-05-01

    Transit-time flow measurement is widely accepted as an intra-operative assessment in coronary artery bypass grafting (CABG). However, the two most commonly applied flowmeters, manufactured by MediStim ASA and Transonic Inc., have different default filter settings of 20 and 10 Hz, respectively. This may cause different flow measurements, which will influence the reported results. The aim was to compare pulsatility index (PI) values recorded by the MediStim and Transonic flowmeters in two different clinical settings: (1) analysis of the flow patterns recorded simultaneously by both flowmeters in the same CABGs; and (2) evaluation of flow patterns under different levels of filter settings in the same grafts. Graft flow and PI were measured using the two different flowmeters simultaneously in 19 bypass grafts. Finally, eight grafts were assessed under different digital filter settings at 5, 10, 20, 30, 50 and 100 Hz. The Transonic flowmeter provided substantially lower PI as compared with the MediStim flowmeter. By increasing the filter setting in the flowmeter, PI increased considerably. The Transonic flowmeter displayed a lower PI than the MediStim, due to a lower filter setting. In the Transonic,flow signals are filtered at a lower level, rendering a 'smoother' pattern of flow curves. Because different filter settings determine different PIs, caution must be taken when flow values and flowmeters are compared. The type of flowmeter should be indicated whenever graft flow measurements and derived indexes are provided [corrected]. Copyright 2009 European Association for Cardio-Thoracic Surgery. All rights reserved.

  12. Gas exchange efficiency of an oxygenator with integrated pulsatile displacement blood pump for neonatal patients.

    Science.gov (United States)

    Schlanstein, Peter C; Borchardt, Ralf; Mager, Ilona; Schmitz-Rode, Thomas; Steinseifer, Ulrich; Arens, Jutta

    2014-01-01

    Oxygenators have been used in neonatal extracorporeal membrane oxygenation (ECMO) since the 1970s. The need to develop a more effective oxygenator for this patient cohort exists due to their size and blood volume limitations. This study sought to validate the next design iteration of a novel oxygenator for neonatal ECMO with an integrated pulsatile displacement pump, thereby superseding an additional blood pump. Pulsating blood flow within the oxygenator is generated by synchronized active air flow expansion and contraction of integrated silicone pump tubes and hose pinching valves located at the oxygenator inlet and outlet. The current redesign improved upon previous prototypes by optimizing silicone pump tube distribution within the oxygenator fiber bundle; introduction of an oval shaped inner fiber bundle core, and housing; and a higher fiber packing density, all of which in combination reduced the priming volume by about 50% (50 to 27 mL and 41 to 20 mL, respectively). Gas exchange efficiency was tested for two new oxygenators manufactured with different fiber materials: one with coating and one with smaller pore size, both capable of long-term use (OXYPLUS® and CELGARD®). Results demonstrated that the oxygen transfer for both oxygenators was 5.3-24.7 mlO2/min for blood flow ranges of 100-500 mlblood/min. Carbon dioxide transfer for both oxygenators was 3.7-26.3 mlCO2/min for the same blood flow range. These preliminary results validated the oxygenator redesign by demonstrating an increase in packing density and thus in gas transfer, an increase in pumping capacity and a reduction in priming volume.

  13. Sigmoid sinus diverticulum and pulsatile tinnitus - Analysis of CT scans from 15 cases

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Zhaohui; Wang, Zhenchang; Xian, Junfang; Wang, Yongzhe; Liang, Xihong [Dept. of Radiology, Capital Medical Univ., Beijing Tongren Hospital, Beijing (China); Chen, Chengfang; Gong, Shusheng; Ma, Xiaobo; Li, Yi [Dept. of Otolaryngology Head and Neck Surgery, Capital Medical Univ., Beijing Tongren Hospital, Beijing (China)

    2013-09-15

    Background: Although the imaging features of sigmoid sinus diverticulum induced pulsatile tinnitus (PT) have been presented in some extent, detailed imaging findings still have not been systematically evaluated and precise diagnostic radiographic criteria has not been established. Purpose: To examine the computed tomography (CT) characteristics of sigmoid sinus diverticulum accompanied with PT. Material and Methods: Fifteen PT patients with sigmoid sinus diverticula proven by surgery were recruited after consenting. CT images of 15 patients were obtained and analyzed, including features of diverticula, brain venous systems, integrity of the sigmoid plate, and the degree of temporal bone pneumatization. Results: Sigmoid sinus diverticulum was located on the same side of PT in 15 patients. Diverticula originated at the superior curve of the sigmoid sinus in 11 patients and the descending segment of the sigmoid sinus in four patients. Sigmoid sinus diverticula focally eroded into the adjacent mastoid air cells in 12 patients and mastoid cortex in three patients. Among eight patients with unilateral dominant brain venous systems, the diverticula were seen on the dominant side in seven patients and non-dominant side in one patient. In contrast, the other seven patients showed co-dominant brain venous systems, with three presenting diverticula on the right side and four on the left. More notably, dehiscent sigmoid plate on the PT side was demonstrated in all patients. In addition, temporal bone hyper-pneumatization was found in nine patients, good and moderate pneumatization in three patients, respectively. Conclusion: Dehiscent sigmoid plate and extensive temporal bone pneumatization are two important imaging characteristics of the PT induced by sigmoid sinus diverticulum.

  14. Simulation of a pulsatile total artificial heart: Development of a partitioned Fluid Structure Interaction model

    Science.gov (United States)

    Sonntag, Simon J.; Kaufmann, Tim A. S.; Büsen, Martin R.; Laumen, Marco; Linde, Torsten; Schmitz-Rode, Thomas; Steinseifer, Ulrich

    2013-04-01

    Heart disease is one of the leading causes of death in the world. Due to a shortage in donor organs artificial hearts can be a bridge to transplantation or even serve as a destination therapy for patients with terminal heart insufficiency. A pusher plate driven pulsatile membrane pump, the Total Artificial Heart (TAH) ReinHeart, is currently under development at the Institute of Applied Medical Engineering of RWTH Aachen University.This paper presents the methodology of a fully coupled three-dimensional time-dependent Fluid Structure Interaction (FSI) simulation of the TAH using a commercial partitioned block-Gauss-Seidel coupling package. Partitioned coupling of the incompressible fluid with the slender flexible membrane as well as a high fluid/structure density ratio of about unity led inherently to a deterioration of the stability (‘artificial added mass instability’). The objective was to conduct a stable simulation with high accuracy of the pumping process. In order to achieve stability, a combined resistance and pressure outlet boundary condition as well as the interface artificial compressibility method was applied. An analysis of the contact algorithm and turbulence condition is presented. Independence tests are performed for the structural and the fluid mesh, the time step size and the number of pulse cycles. Because of the large deformation of the fluid domain, a variable mesh stiffness depending on certain mesh properties was specified for the fluid elements. Adaptive remeshing was avoided. Different approaches for the mesh stiffness function are compared with respect to convergence, preservation of mesh topology and mesh quality. The resulting mesh aspect ratios, mesh expansion factors and mesh orthogonalities are evaluated in detail. The membrane motion and flow distribution of the coupled simulations are compared with a top-view recording and stereo Particle Image Velocimetry (PIV) measurements, respectively, of the actual pump.

  15. An original valveless artificial heart providing pulsatile flow tested in mock circulatory loops.

    Science.gov (United States)

    Tozzi, Piergiorgio; Maertens, Audrey; Emery, Jonathan; Joseph, Samuel; Kirsch, Matthias; Avellan, François

    2017-11-24

    We present the test bench results of a valveless total artificial heart that is potentially compatible with the pediatric population. The RollingHeart is a valveless volumetric pump generating pulsatile flow. It consists of a single spherical cavity divided into 4 chambers by 2 rotating disks. The combined rotations of both disks produce changes in the volumes of the 4 cavities (suction and ejection). The blood enters/exits the spherical cavity through 4 openings that are symmetrical to the fixed rotation axis of the first disk.Mock circulatory system: The device pumps a 37% glycerin solution through 2 parallel circuits, simulating the pulmonary and systemic circulations. Flow rates are acquired with a magnetic inductive flowmeter, while pressure sensors collect pressure in the left and right outflow and inflow tracts.In vitro test protocol: The pump is run at speeds ranging from 20 to 180 ejections per minute. The waveform of the pressure generated at the inflow and outflow of the 4 chambers and the flow rate in the systemic circulation are measured. At an ejection rate of 178 min-1, the RollingHeart pumps 5.3 L/min for a systemic maximal pressure gradient of 174 mmHg and a pulmonary maximal pressure gradient of 75 mmHg. The power input was 14 W, corresponding to an efficiency of 21%. The RollingHeart represents a new approach in the domain of total artificial heart. This preliminary study endorses the feasibility of a single valveless device acting as a total artificial heart.

  16. Verification of a computational cardiovascular system model comparing the hemodynamics of a continuous flow to a synchronous valveless pulsatile flow left ventricular assist device.

    Science.gov (United States)

    Gohean, Jeffrey R; George, Mitchell J; Pate, Thomas D; Kurusz, Mark; Longoria, Raul G; Smalling, Richard W

    2013-01-01

    The purpose of this investigation is to use a computational model to compare a synchronized valveless pulsatile left ventricular assist device with continuous flow left ventricular assist devices at the same level of device flow, and to verify the model with in vivo porcine data. A dynamic system model of the human cardiovascular system was developed to simulate the support of a healthy or failing native heart from a continuous flow left ventricular assist device or a synchronous pulsatile valveless dual-piston positive displacement pump. These results were compared with measurements made during in vivo porcine experiments. Results from the simulation model and from the in vivo counterpart show that the pulsatile pump provides higher cardiac output, left ventricular unloading, cardiac pulsatility, and aortic valve flow as compared with the continuous flow model at the same level of support. The dynamic system model developed for this investigation can effectively simulate human cardiovascular support by a synchronous pulsatile or continuous flow ventricular assist device.

  17. Negative feedback governs gonadotrope frequency-decoding of gonadotropin releasing hormone pulse-frequency.

    Directory of Open Access Journals (Sweden)

    Stefan Lim

    Full Text Available The synthesis of the gonadotropin subunits is directed by pulsatile gonadotropin-releasing hormone (GnRH from the hypothalamus, with the frequency of GnRH pulses governing the differential expression of the common alpha-subunit, luteinizing hormone beta-subunit (LHbeta and follicle-stimulating hormone beta-subunit (FSHbeta. Three mitogen-activated protein kinases, (MAPKs, ERK1/2, JNK and p38, contribute uniquely and combinatorially to the expression of each of these subunit genes. In this study, using both experimental and computational methods, we found that dual specificity phosphatase regulation of the activity of the three MAPKs through negative feedback is required, and forms the basis for decoding the frequency of pulsatile GnRH. A fourth MAPK, ERK5, was shown also to be activated by GnRH. ERK5 was found to stimulate FSHbeta promoter activity and to increase FSHbeta mRNA levels, as well as enhancing its preference for low GnRH pulse frequencies. The latter is achieved through boosting the ultrasensitive behavior of FSHbeta gene expression by increasing the number of MAPK dependencies, and through modulating the feedforward effects of JNK activation on the GnRH receptor (GnRH-R. Our findings contribute to understanding the role of changing GnRH pulse-frequency in controlling transcription of the pituitary gonadotropins, which comprises a crucial aspect in regulating reproduction. Pulsatile stimuli and oscillating signals are integral to many biological processes, and elucidation of the mechanisms through which the pulsatility is decoded explains how the same stimulant can lead to various outcomes in a single cell.

  18. Observation of the CSF pulsatile flow in the aqueduct using cine MRI with presaturation bolus tracking, 3

    International Nuclear Information System (INIS)

    Nakajima, Satoshi

    1992-01-01

    The to-and-fro motion patterns of the CSF flow in the aqueduct in ten normal adults, ten patients with secondary normal-pressure hydrocephalus (NPH), and fourteen patients with idiopathic ventriculomegaly were analyzed using cine MRI with presaturation bolus tracking. The to-and-fro motion patterns of the CSF flow in the aqueduct were thus classified into four types according to their maximum velocity and the relative time duration of their flow in the rostral and caudal directions. The correlation between the clinical symptoms, the CT findings, the RI-cisternography findings, the results of the ICP monitorings, and the CSF pulsatile-flow patterns were then analyzed. In secondary NPH disclosing frequent B waves on ICP monitoring, the maximum velocity of the CSF flow in the aqueduct was over 15 mm/sec, and the duration of the CSF flow was longer in the caudal direction than in the rostral direction. Furthermore, the faster the maximum velocity of the CSF flow, the larger the ventricular size on CT and the more severe the CSF malabsorption on cisternography. In idiopathic ventriculomegaly, only two cases demonstrated the same CSF flow pattern as was shown in secondary NPH; the other cases demonstrated other CSF flow patterns, which were considered to indicate hydrocephalus ex vacuo or arrested hydrocephalus. The CSF pulsatile-flow pattern was assumed to change according to the degree of the CSF circulatory disorder, its compensatory process, and the plasticity of the brain. The investigation of the CSF pulsatile flow gives important information for the evaluation of various hydrocephalic conditions. (author)

  19. Deconstructing continuous flash suppression.

    Science.gov (United States)

    Yang, Eunice; Blake, Randolph

    2012-03-08

    In this paper, we asked to what extent the depth of interocular suppression engendered by continuous flash suppression (CFS) varies depending on spatiotemporal properties of the suppressed stimulus and CFS suppressor. An answer to this question could have implications for interpreting the results in which CFS influences the processing of different categories of stimuli to different extents. In a series of experiments, we measured the selectivity and depth of suppression (i.e., elevation in contrast detection thresholds) as a function of the visual features of the stimulus being suppressed and the stimulus evoking suppression, namely, the popular "Mondrian" CFS stimulus (N. Tsuchiya & C. Koch, 2005). First, we found that CFS differentially suppresses the spatial components of the suppressed stimulus: Observers' sensitivity for stimuli of relatively low spatial frequency or cardinally oriented features was more strongly impaired in comparison to high spatial frequency or obliquely oriented stimuli. Second, we discovered that this feature-selective bias primarily arises from the spatiotemporal structure of the CFS stimulus, particularly within information residing in the low spatial frequency range and within the smooth rather than abrupt luminance changes over time. These results imply that this CFS stimulus operates by selectively attenuating certain classes of low-level signals while leaving others to be potentially encoded during suppression. These findings underscore the importance of considering the contribution of low-level features in stimulus-driven effects that are reported under CFS.

  20. RELEASE AND MUCOADHESION PROPERTIES OF DICLOFENAC MATRIX TABLETS FROM NATURAL AND SYNTHETIC POLYMER BLENDS.

    Science.gov (United States)

    Odeniyi, Michael A; Khan, Nasir H; Peh, Kok K

    2015-01-01

    The delayed release and mucoadhesive properties of Cedrela gum and hydroxypropylmethylcellulose blend in diclofenac sodium tablet formulations were evaluated. Tablets were prepared by direct compression and the crushing strength and detachment force were found to increase from 74.49 ± 1.22 to 147.25 ± 2.57 N and 0.302 ± 0.36 to 1.141 ± 0.05 N from low to high level of polymers, respectively. The release kinetics followed Korsmeyer-Peppas release and the n varied between 0.834 and 1.273, indicating that the release mechanism shifts from Fickian to super case I (anomalous release). The drug release profile fits a pulsatile-release pattern characterized by a lag time followed by a more or less rapid and complete drug release. The Cedrela gum-hydroxypropylmethylcelluse blend tablets delayed diclofenac release for 2 h and sustained the release for 12 h. The polymer blend delayed drug release in the 0.1 M HCl simulating gastric environment and subsequent release pH 6.8 phosphate buffer.

  1. Increased basal and pulsatile secretion of FSH and LH in young men with 47,XXY or 46,XX karyotypes

    DEFF Research Database (Denmark)

    Aksglaede, L.; Jensen, Rikke Bodin Beck; Carlsen, E.

    2008-01-01

    testicular failure due to supernumerary X chromosomes. DESIGN: Cross-sectional study. METHODS: In this study, 7 untreated patients with primary gonadal insufficiency due to SRY-positive 46,XX (n=4) and 46,XXY karyotypes (n=3) aged 18.8 years and 25 age-matched healthy controls participated. Reproductive...... basal, pulsatile, and total LH and FSH secretion were associated with significantly more LH peaks per 24 h in comparison with healthy controls. Thus, our data indicate that in patients with Klinefelter syndrome and XX male karyotypes the entire hypothalamic-pituitary-gonadal axis has undergone...

  2. The pulsatility index and the resistive index in renal arteries. Associations with long-term progression in chronic renal failure

    DEFF Research Database (Denmark)

    Petersen, L J; Petersen, J R; Talleruphuus, U

    1997-01-01

    The pulsatility index (PI) and the resistive index (RI) are used as pulsed-wave Doppler measurements of downstream renal artery resistance. PI and RI have been found to correlate with renal vascular resistance, filtration fraction and effective renal plasma flow in chronic renal failure. The aim...... of the present study was to evaluate the potential relationship between these indices and the rate of decline in renal function, as reflected by changes in different parameters of renal function in patients with chronic renal failure....

  3. The pulsatility index and the resistive index in renal arteries in patients with hypertension and chronic renal failure

    DEFF Research Database (Denmark)

    Petersen, L J; Petersen, J R; Ladefoged, S D

    1995-01-01

    The pulsatility index (PI) and the resistive index (RI) are used as pulsed-wave Doppler measurement of downstream renal artery resistance. Little information is available on their value in chronic renal failure and their correlation to parameters of renal function and haemodynamics. The aim...... was to compare PI and RI of renal arteries in healthy volunteers and in patients with hypertension and chronic renal failure, and furthermore to study the correlation of these indices to measurements of renal haemodynamics and function by standard methods in patients with renal failure and hypertension....

  4. Pulsatile Hyperglycaemia Induces Vascular Oxidative Stress and GLUT 1 Expression More Potently than Sustained Hyperglycaemia in Rats on High Fat Diet

    DEFF Research Database (Denmark)

    Rakipovski, Gunaj; Lykkesfeldt, Jens; Raun, Kirsten

    2016-01-01

    expression of glucose transporter 1 (GLUT1), gp-91(PHOX) and super oxide dismutase (SOD), while only the PLG group showed increased accumulation of oxidative stress and oxidised low density lipoprotein (oxLDL) in aorta. Conclusion Pulsatile hyperglycaemia induced relatively higher levels of oxidative stress......Introduction Pulsatile hyperglycaemia resulting in oxidative stress may play an important role in the development of macrovascular complications. We investigated the effects of sustained vs. pulsatile hyperglycaemia in insulin resistant rats on markers of oxidative stress, enzyme expression...... and glucose metabolism in liver and aorta. We hypothesized that liver's ability to regulate the glucose homeostasis under varying states of hyperglycaemia may indirectly affect oxidative stress status in aorta despite the amount of glucose challenged with. Methods Animals were infused with sustained high (SHG...

  5. Real time monitoring of pulsatile change in hemoglobin concentrations of cerebral tissue by a portable tissue oximeter with a 10-Hz sampling rate

    Science.gov (United States)

    Shiga, Toshikazu; Chihara, Eiichi; Tanabe, Kazuhisa; Tanaka, Yoshifumi; Yamamoto, Katsuyuki

    1998-01-01

    A portable CW tissue oximeter of a 10-Hz sampling rate was developed for examination of pulsatile components of the output signals as a mean of checking the signal reliability during long-term monitoring. Feasible studies were performed on a healthy subject. Changes in Hb and HbO2 signals of cerebral tissue were continuously measured by placing a photoprobe on the forehead during 6-hour sleep. Pulsatile changes in Hb and HbO2 were steadily observed over a whole period of the recording. The phase relation of pulsation in Hb and HbO2 was almost inverse. Not only information for reliable monitoring but also physiological parameters with respect to cerebral circulation and metabolism could be obtained by measuring the pulsatile components.

  6. Methane release

    International Nuclear Information System (INIS)

    Seifert, M.

    1999-01-01

    The Swiss Gas Industry has carried out a systematic, technical estimate of methane release from the complete supply chain from production to consumption for the years 1992/1993. The result of this survey provided a conservative value, amounting to 0.9% of the Swiss domestic output. A continuation of the study taking into account new findings with regard to emission factors and the effect of the climate is now available, which provides a value of 0.8% for the target year of 1996. These results show that the renovation of the network has brought about lower losses in the local gas supplies, particularly for the grey cast iron pipelines. (author)

  7. Fetal umbilical artery Doppler pulsatility index and childhood neurocognitive outcome at 12 years.

    Science.gov (United States)

    Mone, Fionnuala; McConnell, Barbara; Thompson, Andrew; Segurado, Ricardo; Hepper, Peter; Stewart, Moira C; Dornan, James C; Ong, Stephen; McAuliffe, Fionnuala M; Shields, Michael D

    2016-06-15

    To determine whether an elevated fetal umbilical artery Doppler (UAD) pulsatility index (PI) at 28 weeks' gestation, in the absence of fetal growth restriction (FGR) and prematurity, is associated with adverse neurocognitive outcome in children aged 12 years. Prospective cohort study, comparing children with a normal fetal UAD PI (<90th centile) (n=110) and those with an elevated PI (≥90th centile) (n=40). UAD was performed at 28, 32 and 34 weeks gestation. At 12 years of age, all children were assessed under standardised conditions at Queen's University, Belfast, UK to determine cognitive and behavioural outcomes using the British Ability Score-II and Achenbach Child Behavioural Checklist Parent Rated Version under standardised conditions. Regression analysis was performed, controlling for confounders such as gender, socioeconomic status and age at assessment. The mean age of follow-up was 12.4 years (±0.5 SD) with 44% of children male (n=63). When UAD was assessed at 28 weeks, the elevated fetal UAD group had lower scores in cognitive assessments of information processing and memory. Parameters included (1) recall of objects immediate verbal (p=0.002), (2) delayed verbal (p=0.008) and (3) recall of objects immediate spatial (p=0.0016). There were no significant differences between the Doppler groups at 32 or 34 weeks' gestation. An elevated UAD PI at 28 weeks' gestation in the absence of FGR or prematurity is associated with lower scores of declarative memory in children aged 12 years. A potential explanation for this is an element of placental insufficiency in the presence of the appropriately grown fetus, which affects the development of the fetal hippocampus and information processing and memory long-term. These findings, however, had no impact on overall academic ability, mental processing and reasoning or overall behavioural function. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a

  8. Impaired Central Pulsatile Hemodynamics in Children and Adolescents With Marfan Syndrome.

    Science.gov (United States)

    Grillo, Andrea; Salvi, Paolo; Marelli, Susan; Gao, Lan; Salvi, Lucia; Faini, Andrea; Trifirò, Giuliana; Carretta, Renzo; Pini, Alessandro; Parati, Gianfranco

    2017-11-07

    Marfan syndrome is characterized by aortic root dilation, beginning in childhood. Data about aortic pulsatile hemodynamics and stiffness in pediatric age are currently lacking. In 51 young patients with Marfan syndrome (12.0±3.3 years), carotid tonometry was performed for the measurement of central pulse pressure, pulse pressure amplification, and aortic stiffness (carotid-femoral pulse wave velocity). Patients underwent an echocardiogram at baseline and at 1 year follow-up and a genetic evaluation. Pathogenetic fibrillin-1 mutations were classified between "dominant negative" and "haploinsufficient." The hemodynamic parameters of patients were compared with those of 80 sex, age, blood pressure, and heart-rate matched controls. Central pulse pressure was significantly higher (38.3±12.3 versus 33.6±7.8 mm Hg; P =0.009), and pulse pressure amplification was significantly reduced in Marfan than controls (17.9±15.3% versus 32.3±17.4%; P Marfan and controls (4.98±1.00 versus 4.75±0.67 m/s). In the Marfan group, central pulse pressure and pulse pressure amplification were independently associated with aortic diameter at the sinuses of Valsalva (respectively, β=0.371, P =0.010; β=-0.271, P =0.026). No significant difference in hemodynamic parameters was found according to fibrillin-1 genotype. Patients who increased aortic Z-scores at 1-year follow-up presented a higher central pulse pressure than the remaining (42.7±14.2 versus 32.3±5.9 mm Hg; P =0.004). Central pulse pressure and pulse pressure amplification were impaired in pediatric Marfan syndrome, and associated with aortic root diameters, whereas aortic pulse wave velocity was similar to that of a general pediatric population. An increased central pulse pressure was present among patients whose aortic dilatation worsened at 1-year follow-up. © 2017 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.

  9. Reference ranges for uterine artery pulsatility index during the menstrual cycle: a cross-sectional study.

    Directory of Open Access Journals (Sweden)

    Luís Guedes-Martins

    Full Text Available Cyclic endometrial neoangiogenesis contributes to changes in local vascular patterns and is amenable to non-invasive assessment with Doppler sonography. We hypothesize that the uterine artery (UtA impedance, measured by its pulsatility index (PI, exhibits a regular pattern during the normal menstrual cycle. Therefore, the main study objective was to derive normative new day-cycle-based reference ranges for the UtA-PI during the entire cycle from days 1 to 34 according to the isolated time effect and potential confounders such as age and parity.From January 2009 to December 2012, a cross-sectional study of 1,821 healthy women undergoing routine gynaecological ultrasound was performed. The Doppler flow of the right and left UtA-PI was studied transvaginally by colour and pulsed Doppler imaging. The mean right and left values and the presence or absence of a bilateral protodiastolic notch were recorded. Reference intervals for the PI according to the cycle day were generated by classical linear regression.The majority of patients (97.5% presented unilateral or bilateral UtA notches. The crude 5th, 50th, and 95th reference percentile curves of the UtA-PI at 1-34 days of the normal menstrual cycle were derived. In all curves, a progressive significant decrease occurred during the first 13 days, followed by an increase and recovery in the UtA-PI. The adjusted 5th, 50th, and 95th reference percentile curves for the effects of age and parity were also obtained. These two conditions generated an approximately identical UtA-PI pattern during the cycle, except with small but significant reductions at the temporal extremes.The median, 5th, and the 95th percentiles of the UtA-PI decrease during the first third of the menstrual cycle and recover to their initial values during the last two thirds of the cycle. The rates of decrease and recovery depend significantly on age and parity.

  10. Pulsatility of Lenticulostriate Arteries Assessed by 7 Tesla Flow MRI-Measurement, Reproducibility, and Applicability to Aging Effect.

    Science.gov (United States)

    Schnerr, Roald S; Jansen, Jacobus F A; Uludag, Kamil; Hofman, Paul A M; Wildberger, Joachim E; van Oostenbrugge, Robert J; Backes, Walter H

    2017-01-01

    Characterization of flow properties in cerebral arteries with 1.5 and 3 Tesla MRI is usually limited to large cerebral arteries and difficult to evaluate in the small perforating arteries due to insufficient spatial resolution. In this study, we assessed the feasibility to measure blood flow waveforms in the small lenticulostriate arteries with 7 Tesla velocity-sensitive MRI. The middle cerebral artery was included as reference. Imaging was performed in five young and five old healthy volunteers. Flow was calculated by integrating time-varying velocity values over the vascular cross-section. MRI acquisitions were performed twice in each subject to determine reproducibility. From the flow waveforms, the pulsatility index and damping factor were deduced. Reproducibility values, in terms of the intraclass correlation coefficients, were found to be good to excellent. Measured pulsatility index of the lenticulostriate arteries significantly increased and damping factor significantly decreased with age. In conclusion, we demonstrate that blood flow through the lenticostriate arteries can be precisely measured using 7 Tesla MRI and reveal effects of arterial stiffness due to aging. These findings hold promise to provide relevant insights into the pathologies involving perforating cerebral arteries.

  11. Non-invasive estimation of pulsatile flow and differential pressure in an implantable rotary blood pump for heart failure patients

    International Nuclear Information System (INIS)

    AlOmari, A H; Savkin, A V; Karantonis, D M; Lim, E; Lovell, N H

    2009-01-01

    We propose dynamical models for pulsatile flow and head estimation in an implantable rotary blood pump. Pulsatile flow and head data were obtained using a circulatory mock loop where fluid solutions with different values of viscosities were used as a blood analogue with varying haematocrit (HCT). Noninvasive measurements of power and pump speed were used with HCT values as inputs to the flow model while the estimated flow was used with the speed as inputs to a head estimation model. Linear regression analysis between estimated and measured flows obtained from a mock loop resulted in a highly significant correlation (R 2 = 0.982) and a mean absolute error (e) of 0.323 L min −1 , while for head, R 2 = 0.933 and e = 7.682 mmHg were obtained. R 2 = 0.849 and e = 0.584 L min −1 were obtained when the same model derived in the mock loop was used for flow estimation in ex vivo porcine data (N = 6). Furthermore, in the steady state, the solution of the presented flow model can be described by a previously designed and verified static model. The models developed herein will play a vital role in developing a robust control system of the pump flow coping with changing physiological demands

  12. Changes in Bone Mineral Density and Metabolic Parameters after Pulsatile Gonadorelin Treatment in Young Men with Hypogonadotropic Hypogonadism

    Directory of Open Access Journals (Sweden)

    Chen-Xi Li

    2015-01-01

    Full Text Available To assess the prevalence of osteoporosis in young men with hypogonadotropic hypogonadism (HH and to investigate the changes of BMD and metabolic parameters, a total of 22 young male patients with HH and 20 healthy controls were enrolled in the study. BMD, biochemical, and hormonal parameters were measured in two groups. Osteoporosis was more prevalent in HH patients (45.45% than the control subjects (10.00% (P<0.001. The patients with HH had lower BMD in lumbar spine 2–4, femoral neck, and total hip (P<0.001, for all and higher fasting insulin (P=0.001, HOMA-IR (P=0.002, and SHBG (P<0.001 compared to the controls. After 6 months of pulsatile gonadorelin treatment, BMI (P=0.021 and BMD in lumbar spine 2–4, femoral neck, and total hip (P=0.002, P=0.003, and P=0.003, resp. increased dramatically and total cholesterol (P=0.034, fasting insulin (P=0.025, HOMA-IR (P=0.021, and SHBG (P=0.001 decreased significantly in HH patients. The study shows a higher prevalence of osteoporosis in young men with HH. Long-term pulsatile gonadorelin treatment indicates a positive effect on BMD and metabolic parameters of HH patients.

  13. The induction of ovulation by pulsatile administration of GnRH: an appropriate method in hypothalamic amenorrhea.

    Science.gov (United States)

    Christou, Fotini; Pitteloud, Nelly; Gomez, Fulgencio

    2017-08-01

    The induction of ovulation by the means of a pump which assures the pulsatile administration of GnRH is a well-known method that applies to women suffering from amenorrhea of hypothalamic origin. Although a simple and efficient method to establish fertility, it is underused. Twelve patients suffering from this condition, 1 Kallmann syndrome, 4 normosmic isolated hypogonadotropic hypogonadism, and 7 functional hypothalamic amenorrhea desiring pregnancy were treated. They underwent one or more cycles of pulsatile GnRH, at a frequency of 90 minutes, either by the intravenous or the subcutaneous route. An initial dose of 5 μg per pulse in the intravenous route was administered and of 15 μg per pulse in the subcutaneous route. The treatment was monitored by regular dosing of gonadotropins, estradiol and progesterone, and the development of follicles and ovulation was monitored by intra-vaginal ultrasonography. All the patients had documented ovulation, after a mean of 17 days on pump stimulation. Single ovulation occurred in 30 of 33 treatment cycles, irrespective of the route of administration. Ovulation resulted in 10 pregnancies over 7 patients (2 pregnancies in 3 of them), distributed in the 3 diagnostic categories. For comparison, a patient with PCOS treated similarly, disclosed premature LH surge without ovulation.

  14. Anti-Mullerian hormone levels do not predict response to pulsatile GnRH in women with hypothalamic amenorrhea.

    Science.gov (United States)

    Billington, Emma O; Corenblum, Bernard

    2016-09-01

    Pulsatile GnRH is used to induce ovulation in women with hypothalamic amenorrhea (HA), but tools to predict response are lacking. We assessed whether baseline AMH levels are associated with response to pulsatile GnRH in 16 women with HA. AMH levels were compared between non-responders and women who achieved follicular development or pregnancy. Median AMH for the cohort was 2.2 ng/mL. AMH levels were undetectable or low in four women, normal in nine and high in three. Follicular development was observed in 13 (81%) women (82% of cycles) and pregnancy achieved in 10 (63%) women (29% of cycles). All four women with low or undetectable AMH had follicular response and three achieved pregnancy. Of the 12 women with normal or high AMH, 10 had a follicular response and seven achieved pregnancy. Median AMH levels were comparable in those who achieved follicular development and those who did not (2.2 ng/mL versus 1.3 ng/mL, p = 0.78) and in those who became pregnant and those who did not (2.2 ng/mL versus 1.9 ng/mL, p = 0.52). In summary, low AMH does not preclude response to ovulation induction in women with HA, suggesting that ovarian potential may not be the primary determinant of AMH concentrations in this population.

  15. Highly Efficient Thermoresponsive Nanocomposite for Controlled Release Applications

    KAUST Repository

    Yassine, Omar

    2016-06-23

    Highly efficient magnetic release from nanocomposite microparticles is shown, which are made of Poly (N-isopropylacrylamide) hydrogel with embedded iron nanowires. A simple microfluidic technique was adopted to fabricate the microparticles with a high control of the nanowire concentration and in a relatively short time compared to chemical synthesis methods. The thermoresponsive microparticles were used for the remotely triggered release of Rhodamine (B). With a magnetic field of only 1 mT and 20 kHz a drug release of 6.5% and 70% was achieved in the continuous and pulsatile modes, respectively. Those release values are similar to the ones commonly obtained using superparamagnetic beads but accomplished with a magnetic field of five orders of magnitude lower power. The high efficiency is a result of the high remanent magnetization of the nanowires, which produce a large torque when exposed to a magnetic field. This causes the nanowires to vibrate, resulting in friction losses and heating. For comparison, microparticles with superparamagnetic beads were also fabricated and tested; while those worked at 73 mT and 600 kHz, no release was observed at the low field conditions. Cytotoxicity assays showed similar and high cell viability for microparticles with nanowires and beads.

  16. Highly Efficient Thermoresponsive Nanocomposite for Controlled Release Applications

    KAUST Repository

    Yassine, Omar; Zaher, Amir; Li, Erqiang; Alfadhel, Ahmed; Perez, Jose E.; Kavaldzhiev, Mincho; Contreras, Maria F.; Thoroddsen, Sigurdur T; Khashab, Niveen M.; Kosel, Jü rgen

    2016-01-01

    Highly efficient magnetic release from nanocomposite microparticles is shown, which are made of Poly (N-isopropylacrylamide) hydrogel with embedded iron nanowires. A simple microfluidic technique was adopted to fabricate the microparticles with a high control of the nanowire concentration and in a relatively short time compared to chemical synthesis methods. The thermoresponsive microparticles were used for the remotely triggered release of Rhodamine (B). With a magnetic field of only 1 mT and 20 kHz a drug release of 6.5% and 70% was achieved in the continuous and pulsatile modes, respectively. Those release values are similar to the ones commonly obtained using superparamagnetic beads but accomplished with a magnetic field of five orders of magnitude lower power. The high efficiency is a result of the high remanent magnetization of the nanowires, which produce a large torque when exposed to a magnetic field. This causes the nanowires to vibrate, resulting in friction losses and heating. For comparison, microparticles with superparamagnetic beads were also fabricated and tested; while those worked at 73 mT and 600 kHz, no release was observed at the low field conditions. Cytotoxicity assays showed similar and high cell viability for microparticles with nanowires and beads.

  17. Mathematical modeling of gonadotropin-releasing hormone signaling.

    Science.gov (United States)

    Pratap, Amitesh; Garner, Kathryn L; Voliotis, Margaritis; Tsaneva-Atanasova, Krasimira; McArdle, Craig A

    2017-07-05

    Gonadotropin-releasing hormone (GnRH) acts via G-protein coupled receptors on pituitary gonadotropes to control reproduction. These are G q -coupled receptors that mediate acute effects of GnRH on the exocytotic secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH), as well as the chronic regulation of their synthesis. GnRH is secreted in short pulses and GnRH effects on its target cells are dependent upon the dynamics of these pulses. Here we overview GnRH receptors and their signaling network, placing emphasis on pulsatile signaling, and how mechanistic mathematical models and an information theoretic approach have helped further this field. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  18. Sodium fire suppression

    Energy Technology Data Exchange (ETDEWEB)

    Malet, J C [DSN/SESTR, Centre de Cadarache, Saint-Paul-lez-Durance (France)

    1979-03-01

    Ignition and combustion studies have provided valuable data and guidelines for sodium fire suppression research. The primary necessity is to isolate the oxidant from the fuel, rather than to attempt to cool the sodium below its ignition temperature. Work along these lines has led to the development of smothering tank systems and a dry extinguishing powder. Based on the results obtained, the implementation of these techniques is discussed with regard to sodium fire suppression in the Super-Phenix reactor. (author)

  19. Sodium fire suppression

    International Nuclear Information System (INIS)

    Malet, J.C.

    1979-01-01

    Ignition and combustion studies have provided valuable data and guidelines for sodium fire suppression research. The primary necessity is to isolate the oxidant from the fuel, rather than to attempt to cool the sodium below its ignition temperature. Work along these lines has led to the development of smothering tank systems and a dry extinguishing powder. Based on the results obtained, the implementation of these techniques is discussed with regard to sodium fire suppression in the Super-Phenix reactor. (author)

  20. Point-of-Care Ultrasonography to Assess Portal Vein Pulsatility and the Effect of Inhaled Milrinone and Epoprostenol in Severe Right Ventricular Failure: A Report of 2 Cases.

    Science.gov (United States)

    Tremblay, Jan-Alexis; Beaubien-Souligny, William; Elmi-Sarabi, Mahsa; Desjardins, Georges; Denault, André Y

    2017-10-15

    This article describes 2 patients with severe acute right ventricular failure causing circulatory shock. Portal vein pulsatility assessed by bedside ultrasonography suggested clinically relevant venous congestion. Management included cardiac preload reduction and combined inhalation of milrinone and epoprostenol to reduce right ventricular afterload. Portal vein ultrasonography may be useful in assessing right ventricular function in the acutely ill patient.

  1. Pulmonary artery pulsatility and effect on vessel diameter assessment in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Shariat, Masoud; Schantz, Daryl; Yoo, Shi-Joon; Wintersperger, Bernd J.; Seed, Mike; Alnafisi, Bahiyah; Chu, Leysia; MacGowan, Christopher K.; Amerom, Joshua van; Grosse-Wortmann, Lars

    2014-01-01

    systolic cine SSFP or MRA in both groups (p < 0.0001). Vessel diameters measured on systolic SSFP were significantly larger than measurements made on diastolic SSFP (p < 0.0001). There was no significant difference between vessel measurements on MRA and measurements on systolic cine SSFP (p = 0.44 for the TOF group and p = 0.79 for ARVC group). Measurements on the MRA datasets were significantly larger than those on diastolic SSFP images (p < 0.0001). Conclusion: Black blood, white blood and MRA sequences are all reproducible CMR methods for the assessment of arterial diameters in children and adolescents. Measurements from systolic phase SSFP images are comparable to those from contrast-enhanced MRA. Therefore, the administration of contrast medium is not necessary in every case. Cine SSFP images offer the additional advantage over the other methods in such that both the largest and the smallest diameter of the vessel during the cardiac cycle can be assessed using this technique. This is even more relevant in highly pulsatile circulations, such as patients with repaired TOF and significant pulmonary insufficiency

  2. Pulmonary artery pulsatility and effect on vessel diameter assessment in magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Shariat, Masoud, E-mail: masoudshariat@gmail.com [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Schantz, Daryl, E-mail: daryl.schantz@gmail.com [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Yoo, Shi-Joon, E-mail: shi-joon.yoo@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Wintersperger, Bernd J., E-mail: bernd.wintersperger@uhn.ca [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Seed, Mike, E-mail: mike.seed@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Department of Cardiology, Hospital for Sick Children, Toronto, Ontario (Canada); Alnafisi, Bahiyah, E-mail: bahiyah.alnafisi@uhn.ca [Department of Medical Imaging, University Health Network, University of Toronto, Toronto, Ontario (Canada); Chu, Leysia, E-mail: leysia_99@yahoo.com [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); MacGowan, Christopher K., E-mail: christopher.macgowan@sickkids.ca [Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Ontario (Canada); Amerom, Joshua van, E-mail: Joshu.vanamerom@sickkids.ca [Department of Physiology and Experimental Medicine, Hospital for Sick Children, Toronto, Ontario (Canada); Grosse-Wortmann, Lars, E-mail: lars.grosse-wortmann@sickkids.ca [Department of Diagnostic Imaging, Hospital for Sick Children, Toronto, Ontario (Canada); Department of Cardiology, Hospital for Sick Children, Toronto, Ontario (Canada)

    2014-02-15

    systolic cine SSFP or MRA in both groups (p < 0.0001). Vessel diameters measured on systolic SSFP were significantly larger than measurements made on diastolic SSFP (p < 0.0001). There was no significant difference between vessel measurements on MRA and measurements on systolic cine SSFP (p = 0.44 for the TOF group and p = 0.79 for ARVC group). Measurements on the MRA datasets were significantly larger than those on diastolic SSFP images (p < 0.0001). Conclusion: Black blood, white blood and MRA sequences are all reproducible CMR methods for the assessment of arterial diameters in children and adolescents. Measurements from systolic phase SSFP images are comparable to those from contrast-enhanced MRA. Therefore, the administration of contrast medium is not necessary in every case. Cine SSFP images offer the additional advantage over the other methods in such that both the largest and the smallest diameter of the vessel during the cardiac cycle can be assessed using this technique. This is even more relevant in highly pulsatile circulations, such as patients with repaired TOF and significant pulmonary insufficiency.

  3. Gonadotropin-releasing hormone for infertility in women with primary hypothalamic amenorrhea. Toward a more-interventional approach.

    Science.gov (United States)

    Kesrouani, A; Abdallah, M A; Attieh, E; Abboud, J; Atallah, D; Makhoul, C

    2001-01-01

    To assess the effectiveness of a protocol of pulsatile gonadotropin releasing-hormone (GnRH) in treating infertility in women with primary hypothalamic amenorrhea. Retrospective analysis of 44 cycles treated at an infertility center. Twenty-four patients with primary hypothalamic amenorrhea were treated intravenously with pulsatile GnRH using 5 micrograms per bolus every 90 minutes. Ultrasound monitoring and cervical assessment by Insler's scoring system allowed timed injection of human chorionic gonadotropin (hCG) and intrauterine insemination if needed. Luteal support was provided with hCG. The ovulation rate was 95% with the 5-microgram dose. A single follicle was produced in 91% of cycles. The overall pregnancy rate per ovulatory cycle was 45%, and the pregnancy rate per patient was 83%. In patients treated previously with exogenous gonadotropins, poor results were observed. Only one case of mild overstimulation was reported. Pulsatile GnRH is an effective and safe method of treating infertility in women with primary hypothalamic amenorrhea, thus simulating normal ovulation; however, more-interventional management, including the qualitative estrogenic response, may lead to optimal results and increase the pregnancy rate.

  4. The Effect of Pulsatile Flow on bMSC-Derived Endothelial-Like Cells in a Small-Sized Artificial Vessel Made by 3-Dimensional Bioprinting

    Directory of Open Access Journals (Sweden)

    Kang Woog Lee

    2018-01-01

    Full Text Available Replacement of small-sized vessels is still challenging. This study is aimed at investigating the possibility of small-sized artificial vessels made by 3-dimensional bioprinting and the effect of pulsatile flow on bMSC-derived endothelial-like cells. Cells were harvested from rabbit bone marrow and primary cultured with or without growth factors. Endothelial differentiation was confirmed by the Matrigel tube formation assay, Western blot, and qRT-PCR. In addition, embedment of endothelial-like cells in an artificial vessel was made by 3-dimensional bioprinting, and the pulsatile flow was performed. For pumped and nonpumped groups, qRT-PCR was performed on CD31 and VE-cadherin gene expression. Endothelial-like cells showed increased gene expression of CD31 and VE-cadherin, and tube formation is observed at each week. Endothelial-like cells grow well in a small-sized artificial vessel made by 3-dimensional bioprinting and even express higher endothelial cell markers when they undergo pulsatile flow condition. Moreover, the pulsatile flow condition gives a positive effect for cell observation not only on the sodium alginate hydrogel layer but also on the luminal surface of the artificial vessel wall. We have developed an artificial vessel, which is a mixture of cells and carriers using a 3-dimensional bioprinting method, and applied pulsatile flow using a peristaltic pump, and we also demonstrated cell growth and differentiation into endothelial cells. This study suggests guidelines regarding a small-sized artificial vessel in the field of tissue engineering.

  5. Basic study of intrinsic elastography: Relationship between tissue stiffness and propagation velocity of deformation induced by pulsatile flow

    Science.gov (United States)

    Nagaoka, Ryo; Iwasaki, Ryosuke; Arakawa, Mototaka; Kobayashi, Kazuto; Yoshizawa, Shin; Umemura, Shin-ichiro; Saijo, Yoshifumi

    2015-07-01

    We proposed an estimation method for a tissue stiffness from deformations induced by arterial pulsation, and named this proposed method intrinsic elastography (IE). In IE, assuming that the velocity of the deformation propagation in tissues is closely related to the stiffness, the propagation velocity (PV) was estimated by spatial compound ultrasound imaging with a high temporal resolution of 1 ms. However, the relationship between tissue stiffness and PV has not been revealed yet. In this study, the PV of the deformation induced by the pulsatile pump was measured by IE in three different poly(vinyl alcohol) (PVA) phantoms of different stiffnesses. The measured PV was compared with the shear wave velocity (SWV) measured by shear wave imaging (SWI). The measured PV has trends similar to the measured SWV. These results obtained by IE in a healthy male show the possibility that the mechanical properties of living tissues could be evaluated by IE.

  6. Evaluation of the renal resistive index and pulsatility index in patients with pleural effusion by duplex Doppler ultrasonography.

    Science.gov (United States)

    Değirmenci, Nevbahar Akcar; Metintaş, Muzaffer; Atlanoglu, Sahinde; Yıldırım, Huseyin

    2013-01-01

    The aim of the study was to evaluate the renal resistive index (RI) and pulsatility index (PI) in patients with pleural effusion (PE). We studied the mean renal RI and PI in 50 patients with PE and 30 healthy volunteers by Doppler sonography. We grouped effusion as unilateral and bilateral. Statistical analysis was done by independent t test and correlation coefficient analysis. The mean RI/PI in healthy volunteers and in PE patients was 0.58/0.93 and 0.72/1.35, respectively. We observed a significantly higher RI and PI in patients when compared with healthy volunteers (all p effusion (0.74 or 1.55, respectively) (p > 0.05). Pleural effusion might result in increased renal impedance as seen in cirrhosis, which is a rather complicated pathophysiological process, without causing any morphological changes in kidneys.

  7. Experience With a Long-term Pulsatile Ventricular Assist Device as a Bridge to Heart Transplant in Adults.

    Science.gov (United States)

    Gómez Bueno, Manuel; Segovia Cubero, Javier; Serrano Fiz, Santiago; Ugarte Basterrechea, Juan; Hernández Pérez, Francisco José; Goirigolzarri Artaza, Josebe; Castedo Mejuto, Evaristo; Burgos Lázaro, Raúl; García Montero, Carlos; Moñivas Palomero, Vanessa; Mingo Santos, Susana; González Román, Ana Isabel; Álvarez Avelló, José Manuel; Vidal Fernández, Mercedes; Forteza Gil, Alberto; Alonso-Pulpón, Luis

    2017-09-01

    Most long-term ventricular assist devices (VADs) that are currently implanted are intracorporeal continuous-flow devices. Their main limitations include their high cost and inability to provide biventricular support. The aim of this study was to describe the results of using paracorporeal pulsatile-flow VADs as a bridge to transplant (BTT) in adult patients. Retrospective analysis of the characteristics, complications, and outcomes of a single-center case series of consecutive patients treated with the EXCOR VAD as BTT between 2009 and 2015. During the study period, 25 VADs were implanted, 6 of them biventricular. Ventricular assist devices were indicated directly as a BTT in 12 patients and as a bridge to decision in 13 due to the presence of potentially reversible contraindications or chance of heart function recovery. Twenty patients (80%) were successfully bridged to heart transplant after a median of 112 days (range, 8-239). The main complications included infectious (52% of patients), neurological events (32%, half of them fatal), bleeding (28%), and VAD malfunction requiring component replacement (28%). Eighty percent of patients with the EXCOR VAD as BTT achieved the goal after an average of almost 4 months of support. The most frequent complications were infectious, and the most severe were neurological. In our enivonment, the use of these pulsatile-flow VAD as BTT is a feasible strategy that obtains similar outcomes to those of intracorporeal continuous-flow devices. Copyright © 2016 Sociedad Española de Cardiología. Published by Elsevier España, S.L.U. All rights reserved.

  8. Thyroxin hormone suppression treatment

    International Nuclear Information System (INIS)

    Samuel, A.M.

    1999-01-01

    One of the important modalities of treatment of thyroid cancer (TC) after surgery is the administration of thyroxin as an adjuvant treatment. The analysis supports the theory that thyroid suppression plays an important role in patient management. 300 μg of thyroxin, as this is an adequate dose for suppression is given. Ideally the dose should be tailored by testing s-TSH levels. However, since a large number of the patients come from out station cities and villages this is impractical. We therefore depend on clinical criteria of hyperthyroid symptoms and adjust the dose. Very few patients need such adjustment

  9. Pressure suppressing device

    International Nuclear Information System (INIS)

    Naito, Makoto.

    1980-01-01

    Purpose: To prevent the pressure in the reactor container from excessively increasing even when vapor leaks from the dry well to a space of the suppression chamber, without passing though the suppression pool at the time of loss of coolant accident. Constitution: When vapor of a high temperature and a high pressure at the time of loss of coolant accident flows from the dry well to the suppression chamber without passing through suppression pool water, vapor dose not condense with pool water, and therefore the pressure within the chamber abnormally increases. For this reason, this abnormal pressure is detected by a pressure detector thereby to start the operations of a blower and a pump. By starting the blower, the pressure in the dry well becomes lower than the pressure in the chamber, and vapor entirely passes through the pool water and entirely condenses with the pool water. By starting the pump, the pool water is sprayed over the space of the chamber, and vapor in the space is condensed. (Yoshino, Y.)

  10. Gliclazide directly inhibits arginine-induced glucagon release

    DEFF Research Database (Denmark)

    Cejvan, Kenan; Coy, David H; Holst, Jens Juul

    2002-01-01

    Arginine-stimulated insulin and somatostatin release is enhanced by the sulfonylurea gliclazide. In contrast, gliclazide inhibits the glucagon response. The aim of the present study was to investigate whether this inhibition of glucagon release was mediated by a direct suppressive effect of glicl......Arginine-stimulated insulin and somatostatin release is enhanced by the sulfonylurea gliclazide. In contrast, gliclazide inhibits the glucagon response. The aim of the present study was to investigate whether this inhibition of glucagon release was mediated by a direct suppressive effect....... In islet perifusions with DC-41-33, arginine-induced glucagon release was inhibited by 66%. We therefore concluded that gliclazide inhibits glucagon release by a direct action on the pancreatic A cell....

  11. Variable impact of CSF flow suppression on quantitative 3.0T intracranial vessel wall measurements.

    Science.gov (United States)

    Cogswell, Petrice M; Siero, Jeroen C W; Lants, Sarah K; Waddle, Spencer; Davis, L Taylor; Gilbert, Guillaume; Hendrikse, Jeroen; Donahue, Manus J

    2018-03-31

    Flow suppression techniques have been developed for intracranial (IC) vessel wall imaging (VWI) and optimized using simulations; however, simulation results may not translate in vivo. To evaluate experimentally how IC vessel wall and lumen measurements change in identical subjects when evaluated using the most commonly available blood and cerebrospinal fluid (CSF) flow suppression modules and VWI sequences. Prospective. Healthy adults (n = 13; age = 37 ± 15 years) were enrolled. A 3.0T 3D T 1 /proton density (PD)-weighted turbo-spin-echo (TSE) acquisition with post-readout anti-driven equilibrium module, with and without Delay-Alternating-with-Nutation-for-Tailored-Excitation (DANTE) was applied. DANTE flip angle (8-12°) and TSE refocusing angle (sweep = 40-120° or 50-120°) were varied. Basilar artery and internal carotid artery (ICA) wall thicknesses, CSF signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and signal ratio (SR) were assessed. Measurements were made by two readers (radiology resident and board-certified neuroradiologist). A Wilcoxon signed-rank test was applied with corrected two-sided P CSF suppression. Addition of the DANTE preparation reduced CSF SNR from 17.4 to 6.7, thereby providing significant (P CSF suppression. The DANTE preparation also resulted in a significant (P CSF CNR improvement (P = 0.87). There was a trend for a difference in blood SNR with vs. without DANTE (P = 0.05). The outer vessel wall diameter and wall thickness values were lower (P CSF suppression and CNR of the approaches evaluated. However, improvements are heterogeneous, likely owing to intersubject vessel pulsatility and CSF flow variations, which can lead to variable flow suppression efficacy in these velocity-dependent modules. 2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2018. © 2018 International Society for Magnetic Resonance in Medicine.

  12. News/Press Releases

    Data.gov (United States)

    Office of Personnel Management — A press release, news release, media release, press statement is written communication directed at members of the news media for the purpose of announcing programs...

  13. J/Ψ suppression

    International Nuclear Information System (INIS)

    Giubellino, P.; Abreu, M.C.; Alessandro, B.; Alexa, C.; Arnaldi, R.; Astruc, J.; Atayan, M.; Baglin, C.; Baldit, A.; Bedjidian, M.; Bellaiche, F.; Beole, S.; Boldea, V.; Bordalo, P.; Bussiere, A.; Capony, V.; Casagrande, L.; Castor, J.; Chambon, T.; Chaurand, B.; Chevrot, I.; Cheynis, B.; Chiavassa, E.; Cicalo, C.; Comets, M.P.; Constantinescu, S.; Cruz, J.; De Falco, A.; De Marco, N.; Dellacasa, G.; Devaux, A.; Dita, S.; Drapier, O.; Espagnon, B.; Fargeix, J.; Filippov, S.N.; Fleuret, F.; Force, P.; Gallio, M.; Gavrilov, Y.K.; Gerschel, C.; Giubellino, P.; Golubeva, M.B.; Gonin, M.; Grigorian, A.A.; Grossiord, J.Y.; Guber, F.F.; Guichard, A.; Gulkaninan, H.; Hakobyan, R.; Haroutunian, R.; Idzik, M.; Jouan, D.; Karavitcheva, T.L.; Kluberg, L.; Kurepin, A.B.; Le Bornec, Y.; Lourenco, C.; Mac Cormick, M.; Macciotta, P.; Marzari-Chiesa, A.; Masera, M.; Masoni, A.; Mehrabyan, S.; Mourgues, S.; Musso, A.; Ohlsson-Malek, F.; Petiau, P.; Piccotti, A.; Pizzi, J.R.; Prado da Silva, W.L.; Puddu, G.; Quintans, C.; Racca, C.; Ramello, L.; Ramos, S.; Rato-Mendes, P.; Riccati, L.; Romana, A.; Sartori, S.; Saturnini, P.; Scomparin, E.; Serci, S.; Shahoyan, R.; Silva, S.; Soave, C.; Sonderegger, P.; Tarrago, X.; Temnikov, P.; Topilskaya, N.S.; Usai, G.; Vale, C.; Vercellin, E.; Willis, N.

    1999-01-01

    The cross section for J/Ψ production in Pb-Pb interactions at 158 GeV per nucleon is measured at the CERN SPS by the NA50 experiment. The final results from the 1995 run are presented here together with preliminary ones from the high-statistics 1996 run. An anomalous J/Ψ suppression is observed in Pb-Pb collisions as compared to extrapolations of the previous results obtained by the NA38 experiment with proton and lighter ion beams. The results of the two runs are in good agreement. The results from the 1996 run allow the study of the onset of the anomalous suppression within the same set of data, showing evidence of a sharp change of behaviour around a value of neutral transverse energy, as measured by our electromagnetic calorimeter, of about 50 GeV

  14. Pressure suppression system for a nuclear reactor

    International Nuclear Information System (INIS)

    Jost, N.

    1977-01-01

    The invention pertains to a pressure suppression system for PWR reactors where the parts enclosing the primary coolant are contained in two pressure-tight separate chambers. According to the invention, these chambers are partly filled with water and are connected with each other below the water surface. This way, gases cannot escape from the containment, not even if a valve and a line are damaged at the same time, as the vapours released condensate in the water of at least one of the other chambers. (HP) [de

  15. Young Adult Psychological Outcome After Puberty Suppression and Gender Reassignment

    NARCIS (Netherlands)

    de Vries, A.L.C.; McGuire, J.K.; Steensma, T.D.; Wagenaar, E.C.F.; Doreleijers, T.A.H.; Cohen-Kettenis, P.T.

    2014-01-01

    BACKGROUND: In recent years, puberty suppression by means of gonadotropin-releasing hormone analogs has become accepted in clinical management of adolescents who have gender dysphoria (GD). The current study is the first longer-term longitudinal evaluation of the effectiveness of this approach.

  16. Engineered Surfaces to Control Secondary Electron Yield for Multipactor Suppression

    Science.gov (United States)

    2017-09-14

    Air Force Institute of Technology AFIT Scholar Theses and Dissertations 9-14-2017 Engineered Surfaces to Control Secondary Electron Yield for...Multipactor Suppression James M. Sattler Follow this and additional works at: https://scholar.afit.edu/etd Part of the Electrical and Electronics Commons... TECHNOLOGY Wright-Patterson Air Force Base, Ohio DISTRIBUTION STATEMENT A. APPROVED FOR PUBLIC RELEASE; DISTRIBUTION UNLIMITED

  17. Puberty suppression in gender identity disorder: the Amsterdam experience

    NARCIS (Netherlands)

    Kreukels, B.P.C.; Cohen-Kettenis, P.T.

    2011-01-01

    The use of gonadotropin-releasing hormone analogs (GnRHa) to suppress puberty in adolescents with gender dysphoria is a fairly new intervention in the field of gender identity disorders or transsexualism. GnRHa are used to give adolescents time to make balanced decisions on any further treatment

  18. Validation of SPARC, a suppression pool aerosol capture model

    International Nuclear Information System (INIS)

    Owczarski, P.C.; Winegardner, W.K.

    1985-09-01

    A study of the potential for atmospheric release in hypothetical severe core melt accidents in BWRs with suppression pools was recently completed using a prototype of the SPARC code. The process of validating SPARC using an experimental data base is the concern of this paper

  19. Comparison between induction effect with pulsatile and continuous oxytocin administration on outcomes of pregnancy in the pregnant women referring to Tabriz 29 Bahman hospital in 2006

    Directory of Open Access Journals (Sweden)

    fahimeh Sehhati

    2008-04-01

    Full Text Available Abstract Background: Insufficient uterine activity or hypotonic uterine contraction is a common reason and the cause of abnormal labor progress that can be corrected with oxytocin. Realizing this fact that undue prolongation of labor may contribute to prenatal morbidity has resulted in using oxytocin infusion in different kinds of ineffective uterine contractions. Materials and methods: In this study, one hundred pregnant women in 29 Bahman hospital participated in a quasi-experimental research and were divided randomly into 2 groups of pulsatile induction as well as continuous induction and were compared in terms of pregnancy outcomes including progress of labor, hyperstimulation, mood of delivery, third stage duration, newborn’s Apgar score, and hyperbilirobinemia. Results: There were no significant differences between the two groups in progress of labor, hyperstimulation rate, newborn’s Apgar score, and hyperbilirobinemia (p>0.05 however, significant differences were observed in labor duration (p=0.022, mood of delivery (p=0.008, and dose of oxytocin (p<0.0005. Conclusion: According to the findings of this study, administration of oxytocin with the feedback pulsatile oxytocin system is easier and more physiologic to establish the effective uterine contraction and reduces duration of labor and cesarean section rate. Moreover, the average dose of oxytocin administered is significantly less in the pulsatile induction group.

  20. Radioimmunoassay of thyrotropin-releasing hormone in euthyroid subjects and in patients with thyroid diseases

    International Nuclear Information System (INIS)

    Foeldes, J.; Tarjan, G.; Varga, F.; Mohari, K.; Janoki, G.

    1992-01-01

    An episodic pattern of fluctuation in serum TRH level was demonstrated in euthyroid males. It is suggested that these rises in serum TRH-IR are due to its pulsatile hypothalamic release, however, it must be remembered that a high proportion of circulating TRH is derived from extrahypothalamic sources. The conception that the TSH surge during late evening is secondary to an increased TRH release could not be proved in the present study. In the euthyroid and primary hypothyroid groups the mean values of serum TRH-IR did not differ, while its level was slightly, but not significantly lower in hyperthyroid patients. The evaluation of a single TRH determination is impeded by the short half-life, low serum level and its production in extrahypothalamic sites, too. (authors)

  1. Drug delivery systems with modified release for systemic and biophase bioavailability.

    Science.gov (United States)

    Leucuta, Sorin E

    2012-11-01

    This review describes the most important new generations of pharmaceutical systems: medicines with extended release, controlled release pharmaceutical systems, pharmaceutical systems for the targeted delivery of drug substances. The latest advances and approaches for delivering small molecular weight drugs and other biologically active agents such as proteins and nucleic acids require novel delivery technologies, the success of a drug being many times dependent on the delivery method. All these dosage forms are qualitatively superior to medicines with immediate release, in that they ensure optimal drug concentrations depending on specific demands of different disease particularities of the body. Drug delivery of these pharmaceutical formulations has the benefit of improving product efficacy and safety, as well as patient convenience and compliance. This paper describes the biopharmaceutical, pharmacokinetic, pharmacologic and technological principles in the design of drug delivery systems with modified release as well as the formulation criteria of prolonged and controlled release drug delivery systems. The paper presents pharmaceutical prolonged and controlled release dosage forms intended for different routes of administration: oral, ocular, transdermal, parenteral, pulmonary, mucoadhesive, but also orally fast dissolving tablets, gastroretentive drug delivery systems, colon-specific drug delivery systems, pulsatile drug delivery systems and carrier or ligand mediated transport for site specific or receptor drug targeting. Specific technologies are given on the dosage forms with modified release as well as examples of marketed products, and current research in these areas.

  2. Abnormal Baseline Brain Activity in Patients with Pulsatile Tinnitus: A Resting-State fMRI Study

    Directory of Open Access Journals (Sweden)

    Lv Han

    2014-01-01

    Full Text Available Numerous investigations studying the brain functional activity of the tinnitus patients have indicated that neurological changes are important findings of this kind of disease. However, the pulsatile tinnitus (PT patients were excluded in previous studies because of the totally different mechanisms of the two subtype tinnitus. The aim of this study is to investigate whether altered baseline brain activity presents in patients with PT using resting-state functional magnetic resonance imaging (rs-fMRI technique. The present study used unilateral PT patients (n=42 and age-, sex-, and education-matched normal control subjects (n=42 to investigate the changes in structural and amplitude of low-frequency (ALFF of the brain. Also, we analyzed the relationships between these changes with clinical data of the PT patients. Compared with normal controls, PT patients did not show any structural changes. PT patients showed significant increased ALFF in the bilateral precuneus, and bilateral inferior frontal gyrus (IFG and decreased ALFF in multiple occipital areas. Moreover, the increased THI score and PT duration was correlated with increased ALFF in precuneus and bilateral IFG. The abnormalities of spontaneous brain activity reflected by ALFF measurements in the absence of structural changes may provide insights into the neural reorganization in PT patients.

  3. Pulsatility Index of Blood Echogenicity of the Human Radial and Common Carotid Arteries: Relation with Age and Stroke

    International Nuclear Information System (INIS)

    Bok, Tae Hoon; Kong, Qi; Nam, Kweon Ho; Choi, Jay Chol; Paeng, Dong Guk

    2012-01-01

    In the present paper, the ultrasound blood images were measured at both the human radial artery(RA) and common carotid artery(CCA), depending on the age, and the pulsatility index of blood echogenicity(PIBE) was analyzed. In addition, the ultrasound blood images were measured at both RA and CCA of both the stroke patients and the control group, and PIBE was compared. PIBE of RA for the young group was similar with that for the old group (0.13±0.21 and 0.16±0.03). PIBE of CCA for the young group, however, was larger than that for the old group (0.70±0.21 and 0.32±0.01), and was more variable depending on the subject. Similarly, the fibrinogen concentrations of the patients (336±61 and 340±126 mg/dl) were more than that of the control group (264±38 and 43 mg/dl), for both RA and CCA. The results indicate the possibility of the ultrasonic test on the correlation between erythrocyte aggregation and stroke, and it is expected that the in-vivo EA measurement would be clinically useful.

  4. Vascular Ehlers-Danlos Syndrome Presenting as a Pulsatile Neck Mass: a Case Report and Review of Literature.

    Science.gov (United States)

    Maraj, Bharat; Harding-Theobald, Emily; Karaki, Fatima

    2018-04-26

    Ehlers-Danlos syndrome refers to a spectrum of connective tissue disorders typically caused by mutations in genes responsible for the synthesis of collagen. Patients with Ehlers-Danlos syndrome often exhibit hyperflexibility of joints, increased skin elasticity, and tissue fragility. Vascular Ehlers-Danlos (vEDS) is a subtype of Ehlers-Danlos syndrome with a predilection to involve blood vessels. As such, it often manifests as vascular aneurysms and vessel rupture leading to hemorrhage. There are few reports describing primary prevention of aneurysms in the setting of undiagnosed, suspected vEDS. We present a case of a 30-year-old woman who presents with a pulsatile neck mass found to have multiple arterial aneurysms on imaging, hyperflexibility, and characteristic facial features consistent with vEDS. As described in this case, management of a suspected connective tissue disorder is a multidisciplinary approach including vascular surgery, medical therapy, and genetic testing to confirm the diagnosis. We review literature regarding the care of patients with vascular Ehlers-Danlos as it might pertain to hospitalized patients.

  5. Carotid flow pulsatility is higher in women with greater decrement in gait speed during multi-tasking.

    Science.gov (United States)

    Gonzales, Joaquin U; James, C Roger; Yang, Hyung Suk; Jensen, Daniel; Atkins, Lee; Al-Khalil, Kareem; O'Boyle, Michael

    2017-05-01

    Central arterial hemodynamics is associated with cognitive impairment. Reductions in gait speed during walking while performing concurrent tasks known as dual-tasking (DT) or multi-tasking (MT) is thought to reflect the cognitive cost that exceeds neural capacity to share resources. We hypothesized that central vascular function would associate with decrements in gait speed during DT or MT. Gait speed was measured using a motion capture system in 56 women (30-80y) without mild-cognitive impairment. Dual-tasking was considered walking at a fast-pace while balancing a tray. Multi-tasking was the DT condition plus subtracting by serial 7's. Applanation tonometry was used for measurement of aortic stiffness and central pulse pressure. Doppler-ultrasound was used to measure blood flow velocity and β-stiffness index in the common carotid artery. The percent change in gait speed was larger for MT than DT (14.1±11.2 vs. 8.7±9.6%, p decrement (third tertile) as compared to women with less decrement (first tertile) in gait speed during MT after adjusting for age, gait speed, and task error. Carotid pulse pressure and β-stiffness did not contribute to these tertile differences. Elevated carotid flow pulsatility and resistance are characteristics found in healthy women that show lower cognitive capacity to walk and perform multiple concurrent tasks. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Zumbido pulsátil: tratamento com clonazepan e propranolol Pulsatile tinnitus: treatment with clonazepam and propranolol

    Directory of Open Access Journals (Sweden)

    Sergio Albertino

    2005-02-01

    Full Text Available O zumbido pulsátil sincrônico com os batimentos cardíacos é pouco freqüente, sendo de etiologia tanto vascular arterial (malformações, fístulas artério-venosas ou venosa (anormalidades do bulbo jugular, tumor glômico jugular ou timpânico. A identificação precoce da etiologia é essencial para que a terapêutica adequada possa ser instituída. A angioressonância possibilita a identificação de alterações vasculares com maior precisão. Relatamos um caso onde, após o diagnóstico de uma alteração vascular arterial, foi instituído o tratamento com propranolol e clonazepam, com melhora da sintomatologia.Pulsatile tinnitus synchronous with heartbeat is rare and normally has vascular origin: arterial (malformation, arterial anatomical variation or venous (aberrant jugular bulb, glomus tumors, tympanic glomus tumor. Early etiology identification is essential for appropriate treatment to be established. Magnetic angioresonance makes the vascular identification possible and precise. We report a case of arterial anatomical variation in which the treatment was propranolol and clonazepam, showing tinnitus improvement.

  7. Flow visualization of three-dimensionality inside the 12 cc Penn State pulsatile pediatric ventricular assist device.

    Science.gov (United States)

    Roszelle, Breigh N; Deutsch, Steven; Manning, Keefe B

    2010-02-01

    In order to aid the ongoing concern of limited organ availability for pediatric heart transplants, Penn State has continued development of a pulsatile Pediatric Ventricular Assist Device (PVAD). Initial studies of the PVAD observed an increase in thrombus formation due to differences in flow field physics when compared to adult sized devices, which included a higher degree of three-dimensionality. This unique flow field brings into question the use of 2D planar particle image velocimetry (PIV) as a flow visualization technique, however the small size and high curvature of the PVAD make other tools such as stereoscopic PIV impractical. In order to test the reliability of the 2D results, we perform a pseudo-3D PIV study using planes both parallel and normal to the diaphragm employing a mock circulatory loop containing a viscoelastic fluid that mimics 40% hematocrit blood. We find that while the third component of velocity is extremely helpful to a physical understanding of the flow, particularly of the diastolic jet and the development of a desired rotational pattern, the flow data taken parallel to the diaphragm is sufficient to describe the wall shear rates, a critical aspect to the study of thrombosis and design of such pumps.

  8. The pressure suppression system

    International Nuclear Information System (INIS)

    Aust, E.

    1985-01-01

    Nuclear plants with boiling water reactors have a safety containment with a pressure suppression system (PSS). Proceeding on significant self-developments, today the three PSS-lines of General Electric Co. (GE), Kraftwerk Union AG (KWU) and ASEA-ATOM are predominant, which are currently represented by the MARK III type, the KWU type 72 and the BWR 75 containment. In addition, there are special developments for the nuclear ship propulsion and for the pressurized water reactors in the Soviet Union. Key design values of the PSS allow a first valuation of its loads during a hypothetical loss-of-coolant accident. (orig.) [de

  9. Cold suppresses agonist-induced activation of TRPV1.

    Science.gov (United States)

    Chung, M-K; Wang, S

    2011-09-01

    Cold therapy is frequently used to reduce pain and edema following acute injury or surgery such as tooth extraction. However, the neurobiological mechanisms of cold therapy are not completely understood. Transient receptor potential vanilloid 1 (TRPV1) is a capsaicin- and heat-gated nociceptive ion channel implicated in thermosensation and pathological pain under conditions of inflammation or injury. Although capsaicin-induced nociception, neuropeptide release, and ionic currents are suppressed by cold, it is not known if cold suppresses agonist-induced activation of recombinant TRPV1. We demonstrate that cold strongly suppressed the activation of recombinant TRPV1 by multiple agonists and capsaicin-evoked currents in trigeminal ganglia neurons under normal and phosphorylated conditions. Cold-induced suppression was partially impaired in a TRPV1 mutant that lacked heat-mediated activation and potentiation. These results suggest that cold-induced suppression of TRPV1 may share a common molecular basis with heat-induced potentiation, and that allosteric inhibition may contribute, in part, to the cold-induced suppression. We also show that combination of cold and a specific antagonist of TRPV1 can produce an additive suppression. Our results provide a mechanistic basis for cold therapy and may enhance anti-nociceptive approaches that target TRPV1 for managing pain under inflammation and tissue injury, including that from tooth extraction.

  10. Planck-suppressed operators

    International Nuclear Information System (INIS)

    Assassi, Valentin; Baumann, Daniel; Green, Daniel; McAllister, Liam

    2014-01-01

    We show that the recent Planck limits on primordial non-Gaussianity impose strong constraints on light hidden sector fields coupled to the inflaton via operators suppressed by a high mass scale Λ. We study a simple effective field theory in which a hidden sector field is coupled to a shift-symmetric inflaton via arbitrary operators up to dimension five. Self-interactions in the hidden sector lead to non-Gaussianity in the curvature perturbations. To be consistent with the Planck limit on local non-Gaussianity, the coupling to any hidden sector with light fields and natural cubic couplings must be suppressed by a very high scale Λ > 10 5 H. Even if the hidden sector has Gaussian correlations, nonlinearities in the mixing with the inflaton still lead to non-Gaussian curvature perturbations. In this case, the non-Gaussianity is of the equilateral or orthogonal type, and the Planck data requires Λ > 10 2 H

  11. Pulsatile blood flow in human bone assessed by laser-Doppler flowmetry and the interpretation of photoplethysmographic signals

    International Nuclear Information System (INIS)

    Binzoni, Tiziano; Tchernin, David; Hyacinthe, Jean-Noël; Van De Ville, Dimitri; Richiardi, Jonas

    2013-01-01

    Human bone blood flow, mean blood speed and the number of moving red blood cells were assessed (in arbitrary units), as a function of time, during one cardiac cycle. The measurements were obtained non-invasively on five volunteers by laser-Doppler flowmetry at large interoptode spacing. The investigated bones included: patella, clavicle, tibial diaphysis and tibial malleolus. As hypothesized, we found that in all bones the number of moving cells remains constant during cardiac cycles. Therefore, we concluded that the pulsatile nature of blood flow must be completely determined by the mean blood speed and not by changes in blood volume (vessels dilation). Based on these results, it is finally demonstrated using a mathematical model (derived from the radiative transport theory) that photoplethysmographic (PPG) pulsations observed by others in the literature, cannot be generated by oscillations in blood oxygen saturation, which is physiologically linked to blood speed. In fact, possible oxygen saturation changes during pulsations decrease the amplitude of PPG pulsations due to specific features of the PPG light source. It is shown that a variation in blood oxygen saturation of 3% may induce a negative change of ∼1% in the PPG signal. It is concluded that PPG pulsations are determined by periodic ‘positive’ changes of the reduced scattering coefficient of the tissue and/or the absorption coefficient at constant blood volume. No explicit experimental PPG measurements have been performed. As a by-product of this study, an estimation of the arterial pulse wave velocity obtained from the analysis of the blood flow pulsations give a value of 7.8 m s −1 (95% confidence interval of the sample mean distribution: [6.7, 9.5] m s −1 ), which is perfectly compatible with data in the literature. We hope that this note will contribute to a better understanding of PPG signals and to further develop the domain of the vascular physiology of human bone. (note)

  12. CTA/V detection of bilateral sigmoid sinus dehiscence and suspected idiopathic intracranial hypertension in unilateral pulsatile tinnitus

    International Nuclear Information System (INIS)

    Xu, Shuaishuai; Xu, Jianrong; Ruan, Shidong; Liu, Shanfeng; Gong, Ruozhen

    2018-01-01

    This aimed to evaluate the prevalence and extent of bilateral sigmoid sinus dehiscence (SSD) and to explore the presence of idiopathic intracranial hypertension (IIH) in patients with unilateral pulsatile tinnitus (PT) with CTA/V. Sixty PT patients (52 females; 40.4 ± 11.6 years [20-72]) who underwent CTA/V and 30 non-PT patients (27 females; 38.4 ± 14.7 years [12-62]) were enrolled in this study. The primary outcome measure was the radiographic presence of SSD. The index of transverse sinus stenosis (ITSS) was obtained by multiplying the stenosis scale values for each transverse sinus, and once was ≥ 4, the presence of IIH was suspected. The prevalence and extent of SSD on symptomatic side (78%; maximum transverse diameter, MTD 0.49 ± 0.23; maximum vertical diameter, MVD 0.50 ± 0.26 cm) were significantly higher and larger than those on asymptomatic side (50%, P < 0.001; MTD 0.35 ± 0.18, P = 0.006; MVD 0.30 ± 0.15 cm, P < 0.001) in the study group and those (20%, P < 0.001; MTD 0.36 ± 0.18, P = 0.073; MVD 0.30 ± 0.22 cm, P < 0.048) in the control group. The presence of SSD showed significant correlation with both PT (logistic regression analysis, OR 4.167 [1.450-11.97]; P = 0.008) and suspected IIH (OR 16.25 [1.893-139.5]; P = 0.011). In PT patients, SSD has a significant correlation with PT and a potential correlation with IIH. (orig.)

  13. Association between idiopathic intracranial hypertension and sigmoid sinus dehiscence/diverticulum with pulsatile tinnitus: a retrospective imaging study

    Energy Technology Data Exchange (ETDEWEB)

    Zhaohui, Liu; Qing, Li [Capital Medical University, Beijing Tongren Hospital, Department of Radiology, Beijing (China); Cheng, Dong; Xiao, Wang; Xiaoyi, Han; Pengfei, Zhao; Han, Lv; Zhenchang, Wang [Capital Medical University, Beijing Friendship Hospital, Department of Radiology, Beijing (China)

    2015-07-15

    The mechanism of occurrence of sigmoid sinus dehiscence/diverticulum (SSDD) in pulsatile tinnitus (PT) patients remains under debate. Its association with idiopathic intracranial hypertension (IIH) lacks evidence, which is important for therapeutic planning and improving the clinical outcome. This study aimed to evaluate the association between SSDD and IIH by comparing the prevalence of several established imaging features of IIH between PT patients with SSDD and healthy volunteers. Thirty-three unilateral PT patients with SSDD identified on CT images and 33 age- and sex-matched healthy volunteers underwent T1-weighted volumetric magnetic resonance imaging (MRI). The optic nerve, pituitary gland, transverse sinus, and ventricles were assessed. The prevalence of established IIH imaging features was compared between the two groups. Furthermore, the PT patients were divided into two subgroups: PT patients with dehiscence only and PT patients with diverticulum. The same statistical analysis was performed on each pathophysiologic entity respectively. The PT patients with SSDD showed a significantly higher prevalence of empty sella (P < 0.001), flattened posterior sclera (P = 0.001), vertical tortuosity of the optic nerve (P = 0.001), protrusion of the optic nerve (P = 0.006), transverse sinus stenosis (P = 0.011), and distension of the optic nerve sheath (P = 0.000). There were no significant differences between the PT and control groups in the maximum widths of the third and fourth ventricles and the lateral ventricle size. In contrast to controls, the imaging findings persisted in both of pathophysiologic entities, except for transverse sinus stenosis. Several IIH imaging features occur more frequently in PT patients with SSDD than in healthy individuals, which suggests a potential correlation between SSDD with PT and IIH. (orig.)

  14. Does the Pulsatile Preservation Machine Have Any Impact in the Discard Rate of Kidneys From Older Donors After Brain Death?

    Science.gov (United States)

    Paredes-Zapata, D; Ruiz-Arranz, A; Rodriguez-Villar, C; Roque-Arda, R; Peri-Cusi, L; Saavedra-Escobar, S; Vizcaino-Elias, F; Garcia-Rodriguez, X; Bohils-Valle, M; Rodriguez-Peña, S; Quijada-Martorell, M; Gonzalez-Rodriguez, J-J; Oppenheimer-Salinas, F; Alcaraz-Asensio, A; Adalia-Bartolome, R

    2015-10-01

    Donors after brain death (DBD) older than 60 years have become 46.8% of our current activity, with higher risk of renal discard rate (RDR). Assessment of kidney suitability requires complementary strategies: macroscopic evaluation, kidney biopsy score (KBS), and renal hemodynamic evaluation with the Pulsatile Perfusion Machine (PPM). Descriptive, cross-sectional, comparative study of kidneys procured and RDR, comparing 3 time periods: 2000 to June 2004, when only KBS were used; July 2004 to 2008 (introduction of PPM and learning period); and 2009 to 2013 (experienced use of PPM). Transplantation criteria were KBS 70 mL/min. Between 2000 and 2013, a 59.2% reduction in DBD kidneys was observed. However, older kidneys had an increase from 33.5% to 46.8%. The RDR had increased, comparing the first to the third period from 25.4% to 38.3%. However, the RDR was lower when kidneys were evaluated with PPM than those evaluated only with KBS and preserved in cold storage (CS) (21.4% versus 43.7%). There was a significant difference in cold ischemia time, because CS kidney was grafted before PPM. During the third period, more kidneys with KBS ≥4 were assigned to PPM. Notwithstanding the decrease in DBD-procured kidneys and the increase in older kidneys during last period, the use of PPM allowed low DR compared with CS. A bias in the results of PPM could be generated when kidneys with higher KBS were excluded from PPM. The use of KBS only to decide acceptance could preclude the use of an additional tool to evaluate suitability. Copyright © 2015 Elsevier Inc. All rights reserved.

  15. Lateralization effects on functional connectivity of the auditory network in patients with unilateral pulsatile tinnitus as detected by functional MRI.

    Science.gov (United States)

    Lv, Han; Zhao, Pengfei; Liu, Zhaohui; Liu, Xuehuan; Ding, Heyu; Liu, Liheng; Wang, Guopeng; Xie, Jing; Zeng, Rong; Chen, Yuchen; Yang, Zhenghan; Gong, Shusheng; Wang, Zhenchang

    2018-02-02

    Unilateral pulsatile tinnitus (PT) was proved to be a kind of disease with brain functional abnormalities within and beyond the auditory network (AN). However, changes in patterns of the lateralization effects of PT are yet to be established. Relationship between the AN and other brain networks in PT patients is also a scientific question need to be answered. In this study, we recruited 23 left-sided, 23 right-sided PT (LSPT, RSPT) patients and 23 normal controls (NC). We combined applied independent component analysis and seed-based functional connectivity (FC) analysis to investigate alteration feature of the FC of the AN by using resting-state functional magnetic resonance imaging (rs-fMRI). Compared with NC, LSPT patients demonstrated disconnected FC within the AN on both sides. Disrupted network integrity between AN and several brain functional networks, including executive control network, self-perceptual network and the limbic network, was also demonstrated in LSPT patient group bilaterally. In contrast, compared with NC, RSPT demonstrated decreased FC within the AN on the left side, but significant increased FC within the AN on the right side (symptomatic side). Enhanced FC between AN and executive control network, self-perceptual network and limbic network was also found mainly on the right side in patients with RSPT. Positive FC between the auditory network and the limbic network may be a reason to explain why RSPT patients are willing to be in the clinic. Briefly, LSPT exhibit disrupted network integrity in brain functional networks. But RSPT is featured by enhanced FC within AN and between networks, especially on the right (symptomatic) side. Corroboration of featured FC helps to reveal the pathophysiological changing process of the brain in patients with PT, providing imaging-based biomarker to distinguish PT from other kind of tinnitus. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Superior semicircular canal dehiscence in relation to the superior petrosal sinus: a potential cause of pulsatile tinnitus

    International Nuclear Information System (INIS)

    Liu, Z.; Bi, W.; Li, J.; Li, Q.; Dong, C.; Zhao, P.; Lv, H.; Wang, Z.

    2015-01-01

    Aim: To examine the association between superior semicircular canal dehiscence (SSCD) and pulsatile tinnitus (PT). Materials and methods: Two SSCD groups included 408 unilateral persistent PT patients, and 511 controls undergoing head and neck dual-phase contrast-enhanced computed tomography (DP-CECT) for reasons other than PT. The prevalence of type I (no the superior petrosal sinus running through the dehiscence) and type II (superior semicircular canal dehiscence in relation to the superior petrosal sinus) SSCD was analysed using chi-square test. Results: SSCD was identified in 5.1% (21/408) of PT ears, significantly different from 2% (8/408) of non-PT ears and 0.7% (7/1022) of controls. There was no significant difference in SSCD prevalence between non-PT ears in the PT group and controls. In the PT group, 15/21 ears were type II SSCD; 6/21 ears were type I. Fifteen combined non-PT and control ears with SSCD included two type II and 13 type I SSCD. The prevalence of type II SSCD in PT ears was significantly higher than that of non-PT ears in both groups, and the prevalence of type I SSCD in PT ears was similar to that of non-PT ears in both groups. Conclusion: Compared with type I SSCD, there may be a causal relationship between type II SSCD and PT. -- Highlights: •The prevalence of type II SSCD in PT ears was significantly higher than that in non-PT ears in both the PT group and controls. •The prevalence of type I SSCD was similar among the PT ears and non-PT ears. •The superior petrosal sinus running through the dehiscence may be essential for SSCD to induce PT. •Venous phase CT images with bone window settings is the modality method to differentiate type II from type I SSCD

  17. Association between idiopathic intracranial hypertension and sigmoid sinus dehiscence/diverticulum with pulsatile tinnitus: a retrospective imaging study

    International Nuclear Information System (INIS)

    Zhaohui, Liu; Qing, Li; Cheng, Dong; Xiao, Wang; Xiaoyi, Han; Pengfei, Zhao; Han, Lv; Zhenchang, Wang

    2015-01-01

    The mechanism of occurrence of sigmoid sinus dehiscence/diverticulum (SSDD) in pulsatile tinnitus (PT) patients remains under debate. Its association with idiopathic intracranial hypertension (IIH) lacks evidence, which is important for therapeutic planning and improving the clinical outcome. This study aimed to evaluate the association between SSDD and IIH by comparing the prevalence of several established imaging features of IIH between PT patients with SSDD and healthy volunteers. Thirty-three unilateral PT patients with SSDD identified on CT images and 33 age- and sex-matched healthy volunteers underwent T1-weighted volumetric magnetic resonance imaging (MRI). The optic nerve, pituitary gland, transverse sinus, and ventricles were assessed. The prevalence of established IIH imaging features was compared between the two groups. Furthermore, the PT patients were divided into two subgroups: PT patients with dehiscence only and PT patients with diverticulum. The same statistical analysis was performed on each pathophysiologic entity respectively. The PT patients with SSDD showed a significantly higher prevalence of empty sella (P < 0.001), flattened posterior sclera (P = 0.001), vertical tortuosity of the optic nerve (P = 0.001), protrusion of the optic nerve (P = 0.006), transverse sinus stenosis (P = 0.011), and distension of the optic nerve sheath (P = 0.000). There were no significant differences between the PT and control groups in the maximum widths of the third and fourth ventricles and the lateral ventricle size. In contrast to controls, the imaging findings persisted in both of pathophysiologic entities, except for transverse sinus stenosis. Several IIH imaging features occur more frequently in PT patients with SSDD than in healthy individuals, which suggests a potential correlation between SSDD with PT and IIH. (orig.)

  18. Toxics Release Inventory (TRI)

    Data.gov (United States)

    U.S. Environmental Protection Agency — The Toxics Release Inventory (TRI) is a dataset compiled by the U.S. Environmental Protection Agency (EPA). It contains information on the release and waste...

  19. Screening for suppression in young children: the Polaroid Suppression test

    NARCIS (Netherlands)

    Pott, J.W.R.; Oosterveen, DK; Van Hof-van Duin, J

    1998-01-01

    Background: Assessment of monocular visual impairment during screening of young children is often hampered by lack of cooperation. Because strabismus, amblyopia, or anisometropia may lead to monocular suppression during binocular viewing conditions, a test was developed to screen far suppression in

  20. Leptin does not mediate short-term fasting-induced changes in growth hormone pulsatility but increases IGF-I in leptin deficiency states.

    Science.gov (United States)

    Chan, Jean L; Williams, Catherine J; Raciti, Patricia; Blakeman, Jennifer; Kelesidis, Theodore; Kelesidis, Iosif; Johnson, Michael L; Thorner, Michael O; Mantzoros, Christos S

    2008-07-01

    States of acute and chronic energy deficit are characterized by increased GH secretion and decreased IGF-I levels. The objective of the study was to determine whether changes in levels of leptin, a key mediator of the adaptation to starvation, regulate the GH-IGF system during energy deficit. We studied 14 healthy normal-weight men and women during three conditions: baseline fed and 72-h fasting (to induce hypoleptinemia) with administration of placebo or recombinant methionyl human leptin (r-metHuLeptin) (to reverse the fasting associated hypoleptinemia). We also studied eight normal-weight women with exercise-induced chronic energy deficit and hypothalamic amenorrhea at baseline and during 2-3 months of r-metHuLeptin treatment. GH pulsatility, IGF levels, IGF and GH binding protein (GHBP) levels were measured. During short-term energy deficit, measures of GH pulsatility and disorderliness and levels of IGF binding protein (IGFBP)-1 increased, whereas leptin, insulin, IGF-I (total and free), IGFBP-4, IGFBP-6, and GHBP decreased; r-metHuLeptin administration blunted the starvation-associated decrease of IGF-I. In chronic energy deficit, total and free IGF-I, IGFBP-6, and GHBP levels were lower, compared with euleptinemic controls; r-metHuLeptin administration had no major effect on GH pulsatility after 2 wk but increased total IGF-I levels and tended to increase free IGF-I and IGFBP-3 after 1 month. The GH/IGF system changes associated with energy deficit are largely independent of leptin deficiency. During acute energy deficit, r-metHuLeptin administration in replacement doses blunts the starvation-induced decrease of IGF-I, but during chronic energy deficit, r-metHuLeptin administration increases IGF-I and tends to increase free IGF-I and IGFBP-3.

  1. Stimulatory effects of neuronally released norepinephrine on renin release in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, Yasuo; Kawazoe, Shinka; Ichihara, Toshio; Shinyama, Hiroshi; Kageyama, Masaaki; Morimoto, Shiro (Osaka Univ. of Pharmaceutical Sciences (Japan))

    1988-10-01

    Extracellular high potassium inhibits renin release in vitro by increasing calcium concentrations in the juxtaglomerular cells. The authors found that the decreased response of renin release from rat kidney cortical slices in high potassium solution changed to a strikingly increased one in the presence of nifedipine at doses over 10{sup {minus}6} M. They then examined the stimulatory effect of extracellular high potassium in the presence of nifedipine on renin release. The enhancement of release was significantly suppressed either by propranolol or by metoprolol but not by prazosin. High potassium plus nifedipine-induced increase in renin release was markedly attenuated by renal denervation. The enhancing effect was not observed when the slices were incubated in calcium-free medium. Divalent cations such as Cd{sup 2+}, Co{sup 2+}, and Mn{sup 2+} blocked this enhancement in a concentration-dependent manner. High potassium elicited an increase in {sup 3}H efflux from the slices preloaded with ({sup 3}H)-norepinephrine. The increasing effect was not influenced by nifedipine but was abolished by the removal of extracellular calcium or by the addition of divalent cations. These observations suggest to us that the high potassium plus nifedipine-induced increase in renin release from the slices is mediated by norepinephrine derived from renal sympathetic nerves and that this neuronally released norepinephrine stimulates renin release via activation of {beta}-adrenoceptors.

  2. Pressure suppression device

    International Nuclear Information System (INIS)

    Yoshida, Toyokazu.

    1976-01-01

    Purpose: To provide a pressure suppression device for a gas cooled reactor wherein the coolant is discharged in a reactor building by a loss-of-coolant accident or the like, the increase in the pressure and temperature is controlled and thermal energy of the discharged coolant of high temperature and high pressure can be absorbed. Constitution: A low heat source unit is provided at the upper part in an inner space of a reactor building provided around the reactor, and at the upper part of the low heat source unit a stirring fan for mixing gas within the building, and a low heat source circulating the low heat source through a pipe is connected to the low heat source unit. The low heat source unit is provided with the pipe arranged in a spiral shape at the upper part of the space of the unit, and a large number of fins are provided at the outer surface of the pipe for increasing the transmission area and improve the heat exchange. When the coolant of high temperature and high pressure has been lost in the building, the thermal energy of the coolant is absorbed by the low heat source unit. (Aizawa, K.)

  3. Novel/conceptual floating pulsatile system using high internal phase emulsion based porous material intended for chronotherapy.

    Science.gov (United States)

    Sher, Praveen; Ingavle, Ganesh; Ponrathnam, Surendra; Benson, James R; Li, Nai-Hong; Pawar, Atmaram P

    2009-01-01

    The aim of the present study was to design a novel/conceptual delivery system using ibuprofen, anticipated for chronotherapy in arthritis with porous material to overcome the formulation limits (multiple steps, polymers, excipients) and to optimize drug loading for a desired release profile suitable for in vitro investigations. The objective of this delivery system lies in the availability of maximum drug amount for absorption in the wee hours as recommended. Drug loading using 3(2) factorial design on porous carrier, synthesized by high internal phase emulsion technique using styrene and divinylbenzene, was done via solvent evaporation using methanol and dichloromethane. The system was evaluated in vitro for drug loading, encapsulation efficiency, and surface characterization by scanning electron, atomic force microscopy, and customized drug release study. This study examined critical parameters such as solvent volume, drug amount, and solvent polarity on investigations related to drug adsorption and release mostly favoring low-polarity solvent dichloromethane. Overall release in all batches ranged 0.98-52% in acidic medium and 71-94% in basic medium. These results exhibit uniqueness in achieving the least drug release of 0.98%, an ideal one, without using any release modifiers, making it distinct from other approaches/technologies for time and controlled release and for chronotherapy.

  4. MR angiography of stenosis and aneurysm models in the pulsatile flow: variation with imaging parameters and concentration of contrast media

    International Nuclear Information System (INIS)

    Park, Kyung Joo; Park, Jae Hyung; Lee, Hak Jong; Won, Hyung Jin; Lee, Dong Hyuk; Min, Byung Goo; Chang, Kee Hyun

    1997-01-01

    The image quality of magnetic resonance angiography (MRA) varies according to the imaging techniques applied and the parameters affected by blood flow patterns, as well as by the shape of the blood vessels. This study was designed to assess the influence on signal intensity and its distribution of the geometry of these vessels, the imaging parameters, and the concentration of contrast media in MRA of stenosis and aneurysm models. MRA was performed in stenosis and aneurysm models made of glass tubes, using pulsatile flow with viscosity and flow profile similar to those of blood. Slice and maximum intensity projection (MIP) images were obtained using various imaging techniques and parameters;there was variation in repetition time, flip angle, imaging planes, and concentrations of contrast media. On slice images of three-dimensional (3D) time-of-flight (TOF) techniques, flow signal intensity was measured at five locations in the models, and contrast ratio was calculated as the difference between flow signal intensity (SI) and background signal intensity (SIb) divided by background signal intensity or (SI-SIb)/SIb. MIP images obtained by various techniques and using various parameters were also analyzed, with emphasis in the stenosis model on demonstrated degree of stenosis, severity of signal void and image distortion, and in the aneurysm model, on degree of visualization, distortion of contour and distribution of signals. In 3D TOF, the shortest TR (36 msec) and the largest FA (50 deg ) resulted in the highest contrast ratio, but larger flip angles did not effectively demonstrate the demonstration of the peripheral part of the aneurysm. Loss of signal was most prominent in images of the stenosis model obtained with parallel or oblique planes to the flow direction. The two-dimensional TOF technique also caused signal void in stenosis, but precisely demonstrated the aneurysm, with dense opacification of the peripheral part. The phase contrast technique showed some

  5. Suppression of fertility in adult cats

    DEFF Research Database (Denmark)

    Goericke-Pesch, Sandra Kathrin; Wehrend, A.; Georgiev, P.

    2014-01-01

    /needed? (iii) sex of the animal? New effective and available methods for hormonal contraception include melatonin implants for short-term post ponement of oestrus in adult queens and slow-release GnRH-agonist implants containing deslorelin (Suprelorin®) for short- and long-term contraception in male and female......Contents: Cats are animals with highly efficient reproduction, clearly pointing to a need for suppression of fertility. Although surgical contraception is highly effective, it is not always the method of choice. This is predominantly because it is cost-intensive, time-consuming and irreversible......, with the latter being of major importance for cat breeders. This article reviews the use of progestins, scleroting agents, immunocontraception, melatonin, GnRH antagonists and finally, GnRH agonists, in adult male and female cats in detail, according to the present state of the art. By now, various scientific...

  6. HIV Care Saves Lives: Viral Suppression is Key PSA (:60)

    Centers for Disease Control (CDC) Podcasts

    2014-11-25

    This 60 second Public Service Announcement is based on the December 2014 Vital Signs. For people living with HIV, Viral suppression is critical. By getting tested and taking HIV medicines, individuals living with HIV can achieve very low levels of HIV in the body.  Created: 11/25/2014 by National Center for Injury Prevention and Control (NCIPC).   Date Released: 11/25/2014.

  7. Safety and efficacy of the Aperio thrombectomy device when compared to the Solitaire AB/FR and the Revive devices in a pulsatile flow system.

    Science.gov (United States)

    Saleh, Mahdi; Spence, John Nathan; Nayak, Sanjeev; Pearce, Gillian; Tennuci, Christopher; Roffe, Christine

    2012-01-01

    There are a limited number of studies comparing the Aperio mechanical thrombectomy device to other stent-based devices. In this paper, we compared the Aperio thrombectomy device to the Solitaire AB, FR and Revive devices in a model of the middle cerebral artery (MCA) within a modified pulsatile flow system. Thrombi made of lamb's blood were placed into a pulsatile flow system perfused with Hartmann's solution at 80 bpm with a mean pressure of 90 mm Hg. 30 experiments were run with each device. Recanalization rates were similar for all three devices (90% with the Solitaire AB, FR, 80% with the Revive, and 90% with the Aperio). The mean number of attempts to retrieve the thrombus was also similar for all three devices (1.7 with the Solitaire AB, FR, 2.1 with the Revive, 1.6 with the Aperio). Clot fragmentation and embolization rates revealed no statistical significance but there was a trend towards lower embolization rates with the Aperio (23% compared to 40% with the Solitaire AB, FR and 47% with the Revive). The Aperio was the fastest to recanalize the MCA (mean of 66 seconds compared to 186 seconds for the Solitaire AB, FR and 169 seconds for the Revive). In this in vitro setting, the Aperio device seems to be an efficacious and safe device when compared to other similar clinically used mechanical thrombectomy devices. Larger clinical trials are warranted.

  8. Suppressive effects of ketamine on macrophage functions

    International Nuclear Information System (INIS)

    Chang Yi; Chen, T.-L.; Sheu, J.-R.; Chen, R.-M.

    2005-01-01

    Ketamine is an intravenous anesthetic agent. Clinically, induction of anesthesia with ketamine can cause immunosuppression. Macrophages play important roles in host defense. In this study, we attempted to evaluate the effects of ketamine on macrophage functions and its possible mechanism using mouse macrophage-like Raw 264.7 cells as the experimental model. Exposure of macrophages to 10 and 100 μM ketamine, which correspond to 0.1 and 1 times the clinically relevant concentration, for 1, 6, and 24 h had no effect on cell viability or lactate dehydrogenase release. When the administered concentration reached 1000 μM, ketamine caused a release of lactate dehydrogenase and cell death. Ketamine, at 10 and 100 μM, did not affect the chemotactic activity of macrophages. Administration of 1000 μM ketamine in macrophages resulted in a decrease in cell migration. Treatment of macrophages with ketamine reduced phagocytic activities. The oxidative ability of macrophages was suppressed by ketamine. Treatment with lipopolysaccharide induced TNF-α, IL-1β, and IL-6 mRNA in macrophages. Administration of ketamine alone did not influence TNF-α, IL-1β, or IL-6 mRNA production. Meanwhile, cotreatment with ketamine and lipopolysaccharide significantly inhibited lipopolysaccharide-induced TNF-α, IL-1β, and IL-6 mRNA levels. Exposure to ketamine led to a decrease in the mitochondrial membrane potential. However, the activity of mitochondrial complex I NADH dehydrogenase was not affected by ketamine. This study shows that a clinically relevant concentration of ketamine (100 μM) can suppress macrophage function of phagocytosis, its oxidative ability, and inflammatory cytokine production possibly via reduction of the mitochondrial membrane potential instead of direct cellular toxicity

  9. Suppression of soil nitrification by plants.

    Science.gov (United States)

    Subbarao, Guntur Venkata; Yoshihashi, Tadashi; Worthington, Margaret; Nakahara, Kazuhiko; Ando, Yasuo; Sahrawat, Kanwar Lal; Rao, Idupulapati Madhusudhana; Lata, Jean-Christophe; Kishii, Masahiro; Braun, Hans-Joachim

    2015-04-01

    Nitrification, the biological oxidation of ammonium to nitrate, weakens the soil's ability to retain N and facilitates N-losses from production agriculture through nitrate-leaching and denitrification. This process has a profound influence on what form of mineral-N is absorbed, used by plants, and retained in the soil, or lost to the environment, which in turn affects N-cycling, N-use efficiency (NUE) and ecosystem health and services. As reactive-N is often the most limiting in natural ecosystems, plants have acquired a range of mechanisms that suppress soil-nitrifier activity to limit N-losses via N-leaching and denitrification. Plants' ability to produce and release nitrification inhibitors from roots and suppress soil-nitrifier activity is termed 'biological nitrification inhibition' (BNI). With recent developments in methodology for in-situ measurement of nitrification inhibition, it is now possible to characterize BNI function in plants. This review assesses the current status of our understanding of the production and release of biological nitrification inhibitors (BNIs) and their potential in improving NUE in agriculture. A suite of genetic, soil and environmental factors regulate BNI activity in plants. BNI-function can be genetically exploited to improve the BNI-capacity of major food- and feed-crops to develop next-generation production systems with reduced nitrification and N2O emission rates to benefit both agriculture and the environment. The feasibility of such an approach is discussed based on the progresses made. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  10. Center for Corporate Climate Leadership: Direct Fugitive Emissions from Refrigeration, Air Conditioning, Fire Suppression, and Industrial Gases

    Science.gov (United States)

    This guidance document focuses on several fugitive emissions sources that are common for organizations in many sectors: refrigeration and air conditioningsystems, fire suppression systems, and the purchase and release of industrial gases.

  11. Population suppression in support of the sterile insect technique

    International Nuclear Information System (INIS)

    Mangan, R.L.

    2005-01-01

    Suppression or eradication of insect pest populations by the release of sterile insects is often dependent on supplementary methods of pest reduction to levels where the target pest population can be overflooded with sterile insects. Population suppression activities take place in advance of, or coincide with, the production of sterile insects. Supplementary methods to remove breeding opportunities, or management methods that prevent access of pests to the hosts, may reduce the population or prevent damage. Insecticides have been used widely in direct applications or applied as baits, in traps, or on specific sites where the pest makes contact or reproduces. As sterile insect release does not kill the pest, adult biting pests or fertile mated females of the pests will continue to attack hosts after the release of sterile insects. Thus supplementary pest suppression programmes and quarantine measures are essential to prevent damage or the spread of disease. Eradication or effective pest management requires that the entire population of the pest be treated, or that the programme apply immigration barriers. When supplementary pest control activities benefit the human population in areas being treated, such as in mosquito or screwworm eradication programmes, these activities are usually acceptable to the public, but when the public receives no direct benefit from supplementary control activities such as in fruit fly programmes, social resistance may develop. (author)

  12. Atrial distension, haemodilution, and acute control of renin release during water immersion in humans

    DEFF Research Database (Denmark)

    Gabrielsen, A; Pump, B; Bie, P

    2002-01-01

    immersion. During WI, central venous pressure (CVP) and left atrial diameter (LAD) increased (P ... is not the single pivotal stimulus for the acute suppression of renin release in response to intravascular volume expansion by water immersion in humans. Haemodilution constitutes a significant and conceivably the principal stimulus for the acute immersion-induced suppression of renin-angiotensin system activity....

  13. Compton suppression gamma ray spectrometry

    International Nuclear Information System (INIS)

    Landsberger, S.; Iskander, F.Y.; Niset, M.; Heydorn, K.

    2002-01-01

    In the past decade there have been many studies to use Compton suppression methods in routine neutron activation analysis as well as in the traditional role of low level gamma ray counting of environmental samples. On a separate path there have been many new PC based software packages that have been developed to enhance photopeak fitting. Although the newer PC based algorithms have had significant improvements, they still suffer from being effectively used in weak gamma ray lines in natural samples or in neutron activated samples that have very high Compton backgrounds. We have completed a series of experiments to show the usefulness of Compton suppression. As well we have shown the pitfalls when using Compton suppression methods for high counting deadtimes as in the case of neutron activated samples. We have also investigated if counting statistics are the same both suppressed and normal modes. Results are presented in four separate experiments. (author)

  14. Thyroid suppression test with dextrothyroxine

    International Nuclear Information System (INIS)

    Rosenthal, D.; Fridman, J.; Ribeiro, H.B.

    1978-01-01

    The classic thyroid suppression test with triiodothyronine (l-T 3 ) has been shown to be efficient as an auxiliary method in the diagnosis of thyroid diseases, but should not be performed on elderly patients or on those with heart disease or a tendency to tachycardia. Since these subjects seem able to support a short period of dextro-thyronine (d-T 4 ) feeding, we compared the effect of d-T 4 and l-T 3 on the 24 hours thyroid uptake in euthyroid and hyperthyroid subjects. After basal radio-iodine uptake determination, 99 patients without hyperthyroidism and 27 with Graves' disease were randomly divided in 2 groups; one received 100μg of l-T 3 per day and the other 4 mg of d-T 4 per day, both groups being treated for a period of 10 days. At the end of this suppression period the 24 hours radio-iodine uptake was measured again and the percentual suppression index (S.I.) calculated. Since the comparison of the two groups showed no difference between the suppressive effect of l-T 3 and d-T 4 in euthyroid subjects, while dextro-thyronine, as levo-triiodothyronine, did not suppress the 24 hours uptake of hyperthyroid patients, l-T 3 or d-T 4 can be used interchangeably to test thyroid suppressibility. In the euthyroid subjects the normal range for the post-suppression uptake was 0-17.1% and for the suppression index 54,7.100% [pt

  15. Control of anoplophora glabripennis by releasing sterile insects

    International Nuclear Information System (INIS)

    Liu Xiaohui; Li Yongjun; Zhang Shuyong; Wang Endong; Lu Daguang

    2003-01-01

    An experiment to evaluate the effect of released sterile insects on reproduction of natural A. glabripennis population was conducted at a 30-hectare poplar tree forest in Ying County of Shanxi Province from July 10 to August 29, 2001. Though the releasing ratio was only about 2-5, results from different methods showed that the reproduction of natural A. glabripennis population was suppressed effectively by releasing sterile insects, and that hatch ratio of eggs laid by parent generation was about 20% and survival ratio of F1 progeny about 27%. (authors)

  16. Suppressed Charmed B Decay

    Energy Technology Data Exchange (ETDEWEB)

    Snoek, Hella Leonie [Vrije Univ., Amsterdam (Netherlands)

    2009-06-02

    This thesis describes the measurement of the branching fractions of the suppressed charmed B0 → D*- a0+ decays and the non-resonant B0 → D*- ηπ+ decays in approximately 230 million Υ(4S) → B$\\bar{B}$ events. The data have been collected with the BABAR detector at the PEP-II B factory at the Stanford Linear Accelerator Center in California. Theoretical predictions of the branching fraction of the B0 → D*- a{sub 0}+ decays show large QCD model dependent uncertainties. Non-factorizing terms, in the naive factorization model, that can be calculated by QCD factorizing models have a large impact on the branching fraction of these decay modes. The predictions of the branching fractions are of the order of 10-6. The measurement of the branching fraction gives more insight into the theoretical models. In general a better understanding of QCD models will be necessary to conduct weak interaction physics at the next level. The presence of CP violation in electroweak interactions allows the differentiation between matter and antimatter in the laws of physics. In the Standard Model, CP violation is incorporated in the CKM matrix that describes the weak interaction between quarks. Relations amongst the CKM matrix elements are used to present the two relevant parameters as the apex of a triangle (Unitarity Triangle) in a complex plane. The over-constraining of the CKM triangle by experimental measurements is an important test of the Standard Model. At this moment no stringent direct measurements of the CKM angle γ, one of the interior angles of the Unitarity Triangle, are available. The measurement of the angle γ can be performed using the decays of neutral B mesons. The B0 → D*- a0+ decay is sensitive to the angle γ and, in comparison to the current decays that are being employed, could significantly

  17. Large scientific releases

    International Nuclear Information System (INIS)

    Pongratz, M.B.

    1981-01-01

    The motivation for active experiments in space is considered, taking into account the use of active techniques to obtain a better understanding of the natural space environment, the utilization of the advantages of space as a laboratory to study fundamental plasma physics, and the employment of active techniques to determine the magnitude, degree, and consequences of artificial modification of the space environment. It is pointed out that mass-injection experiments in space plasmas began about twenty years ago with the Project Firefly releases. Attention is given to mass-release techniques and diagnostics, operational aspects of mass release active experiments, the active observation of mass release experiments, active perturbation mass release experiments, simulating an artificial modification of the space environment, and active experiments to study fundamental plasma physics

  18. Prospective, randomized comparison between pulsatile GnRH therapy and combined gonadotropin (FSH+LH) treatment for ovulation induction in women with hypothalamic amenorrhea and underlying polycystic ovary syndrome.

    Science.gov (United States)

    Dubourdieu, Sophie; Fréour, Thomas; Dessolle, Lionel; Barrière, Paul

    2013-05-01

    To compare the efficacy of pulsatile GnRH therapy versus combined gonadotropins for ovulation induction in women with both hypothalamic amenorrhoea and polycystic ovarian syndrome (HA/PCOS) according to their current hypothalamic status. This single-centre, prospective, randomized study was conducted in the Nantes University Hospital, France. Thirty consecutive patients were treated for ovulation induction with either pulsatile GnRH therapy or combined gonadotropins (rFSH+rLH). Frequency of adequate ovarian response (mono- or bi-follicular) and clinical pregnancy rate were then compared between both groups. Ovarian response was similar in both groups with comparable frequency of adequate ovarian response (73% vs 60%), but the clinical pregnancy rate was significantly higher in the pulsatile GnRH therapy group than in the combined gonadotropin group (46% vs 0%). HA/PCOS is a specific subgroup of infertile women. Pulsatile GnRH therapy is an effective and safe method of ovulation induction that can be used successfully in these patients. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  19. Evaluation of pulsatility index and diameter of the jugular vein and superficial body temperature as physiological indices of temperament in weaned beef calves: relationship with serum cortisol concentrations, rectal temp..

    Science.gov (United States)

    The relationship between temperament, pulsatility index and diameter of the jugular vein, and body temperature was assessed in Angus crossbred calves (262±24.9 days old). Temperament scores were used to classify calves as calm (n=31), intermediate (n=32), or temperamental (n=28). Blood samples were ...

  20. Psychological Support, Puberty Suppression, and Psychosocial Functioning in Adolescents with Gender Dysphoria

    OpenAIRE

    Costa, Rosalia; Dunsford, Michael; Skagerberg, Elin; Holt, Victoria; Carmichael, Polly; Colizzi, Marco

    2015-01-01

    INTRODUCTION: Puberty suppression by gonadotropin-releasing hormone analogs (GnRHa) is prescribed to relieve the distress associated with pubertal development in adolescents with gender dysphoria (GD) and thereby to provide space for further exploration. However, there are limited longitudinal studies on puberty suppression outcome in GD. Also, studies on the effects of psychological support on its own on GD adolescents' well-being have not been reported.AIM: This study aimed to assess GD ado...

  1. Smoke suppression properties of ferrite yellow on flame retardant thermoplastic polyurethane based on ammonium polyphosphate

    International Nuclear Information System (INIS)

    Chen, Xilei; Jiang, Yufeng; Jiao, Chuanmei

    2014-01-01

    Highlights: • Smoke suppression of FeOOH on flame retardant TPU composites has been investigated. • FeOOH has excellent smoke suppression abilities for flame retardant TPU composites. • FeOOH has good ability of char formation, hence improved smoke suppression property. -- Abstract: This article mainly studies smoke suppression properties and synergistic flame retardant effect of ferrite yellow (FeOOH) on flame retardant thermoplastic polyurethane (TPU) composites using ammonium polyphosphate (APP) as a flame retardant agent. Smoke suppression properties and synergistic flame retardant effect of FeOOH on flame retardant TPU composites were intensively investigated by smoke density test (SDT), cone calorimeter test (CCT), scanning electron microscopy (SEM), and thermal-gravimetric analysis (TGA). Remarkably, the SDT results show that FeOOH can effectively decrease the amount of smoke production with or without flame. On the other hand, the CCT data reveal that the addition of FeOOH can apparently reduce heat release rate (HRR), total heat release (THR), and total smoke release (TSR), etc. Here, FeOOH is considered to be an effective smoke suppression agent and a good synergism with APP in flame retardant TPU composites, which can greatly improve the structure of char residue realized by TGA and SEM results

  2. The Two Populations of Kisspeptin Neurons Are Involved in the Ram-Induced LH Pulsatile Secretion and LH Surge in Anestrous Ewes.

    Science.gov (United States)

    Fabre-Nys, Claude; Cognié, Juliette; Dufourny, Laurence; Ghenim, Meriem; Martinet, Stephanie; Lasserre, Olivier; Lomet, Didier; Millar, Robert P; Ohkura, Satoshi; Suetomi, Yuta

    2017-11-01

    Exposure to a ram during spring stimulates luteinizing hormone (LH) secretion and can induce ovulation in sexually quiescent ewes ("ram effect"). Kisspeptin (Kiss) present in the arcuate nucleus (ARC) and the preoptic area (POA) is a potent stimulators of LH secretion. Our aim was to investigate whether Kiss neurons mediate the increase in LH secretion during the ram effect. With double immunofluorescent detection, we identified Kiss neurons (Kiss IR) activated (Fos IR) by exposure to a ram for 2 hours (M2) or 12 hours (M12) or to ewes for 2 hours (C). The density of cells Kiss + Fos IR and the proportion of Kiss IR cells that were also Fos IR cells were higher in M2 and M12 than in C in ARC (P populations of Kiss neurons are involved in the ram-induced pulsatile LH secretion and in the LH surge. Copyright © 2017 Endocrine Society.

  3. Beyond viral suppression of HIV

    DEFF Research Database (Denmark)

    Lazarus, Jeffrey V.; Safreed-Harmon, Kelly; Barton, Simon E

    2016-01-01

    BACKGROUND: In 2016, the World Health Organization (WHO) adopted a new Global Health Sector Strategy on HIV for 2016-2021. It establishes 15 ambitious targets, including the '90-90-90' target calling on health systems to reduce under-diagnosis of HIV, treat a greater number of those diagnosed......, and ensure that those being treated achieve viral suppression. DISCUSSION: The WHO strategy calls for person-centered chronic care for people living with HIV (PLHIV), implicitly acknowledging that viral suppression is not the ultimate goal of treatment. However, it stops short of providing an explicit target...... for health-related quality of life. It thus fails to take into account the needs of PLHIV who have achieved viral suppression but still must contend with other intense challenges such as serious non-communicable diseases, depression, anxiety, financial stress, and experiences of or apprehension about HIV...

  4. The 2017 Release Cloudy

    Science.gov (United States)

    Ferland, G. J.; Chatzikos, M.; Guzmán, F.; Lykins, M. L.; van Hoof, P. A. M.; Williams, R. J. R.; Abel, N. P.; Badnell, N. R.; Keenan, F. P.; Porter, R. L.; Stancil, P. C.

    2017-10-01

    We describe the 2017 release of the spectral synthesis code Cloudy, summarizing the many improvements to the scope and accuracy of the physics which have been made since the previous release. Exporting the atomic data into external data files has enabled many new large datasets to be incorporated into the code. The use of the complete datasets is not realistic for most calculations, so we describe the limited subset of data used by default, which predicts significantly more lines than the previous release of Cloudy. This version is nevertheless faster than the previous release, as a result of code optimizations. We give examples of the accuracy limits using small models, and the performance requirements of large complete models. We summarize several advances in the H- and He-like iso-electronic sequences and use our complete collisional-radiative models to establish the densities where the coronal and local thermodynamic equilibrium approximations work.

  5. EIA new releases

    International Nuclear Information System (INIS)

    1994-09-01

    This report is a compliation of news releases from the Energy Information Administration. The september-october report includes articles on energy conservation, energy consumption in commercial buildings, and a short term energy model for a personal computer

  6. Abnormal resting-state functional connectivity study in unilateral pulsatile tinnitus patients with single etiology: A seed-based functional connectivity study

    Energy Technology Data Exchange (ETDEWEB)

    Lv, Han [Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050 (China); Neuroradiology Division, Department of Radiology, Stanford University, CA, 94305 (United States); Zhao, Pengfei [Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050 (China); Liu, Zhaohui [Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 (China); Li, Rui; Zhang, Ling; Wang, Peng [Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050 (China); Yan, Fei [Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 (China); Liu, Liheng [Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050 (China); Wang, Guopeng; Zeng, Rong [Department of Otolaryngology Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing 100050 (China); Li, Ting [Department of Radiology, Beijing Tongren Hospital, Capital Medical University, Beijing, 100730 (China); Dong, Cheng [Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050 (China); Gong, Shusheng, E-mail: gongss@ccmu.edu.cn [Department of Otolaryngology Head and Neck Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing 100050 (China); Wang, Zhenchang, E-mail: cjr.wzhch@vip.163.com [Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050 (China)

    2016-11-15

    Objective: Previous studies demonstrated altered regional neural activations in several brain areas in patients with pulsatile tinnitus (PT), especially indicating an important role of posterior cingulate cortex (PCC). However, few studies focused on the degree of functional connectivity (FC) of this area in PT patients. In this study, we will compare the FC of PCC in patients affected with this condition and normal controls by using resting-state functional magnetic resonance imaging (fMRI). Methods: Structural and functional MRI data were obtained from 36 unilateral PT patients with single etiology and 36 matched healthy controls. FC feature of the region of interest (PCC) were characterized using a seed-based correlation method with the voxels in the whole-brain. Results: Compared with healthy controls, patients showed significant decreased FC to the right middle temporal gyrus (MTG), right thalamus and bilateral insula. By contrast, PCC demonstrated increased functional connectivity between the precuneus, bilateral inferior parietal lobule and middle occipital gyrus. We also found correlations between the disease duration of PT and FC of PCC-right MTG (r = −0.616, p < 0.001). Conclusions: Unilateral PT patients could have abnormal FC to the PCC bilaterally in the brain. PCC, as a highly integrated brain area, is an example of nucleus that was involved in mediation between different neural networks. It might be a modulation core between visual network and auditory network. The decreased FC of MTG to PCC may indicate a down regulation of activity between PCC and auditory associated brain cortex. Decreased FC between limbic system (bilateral AI) and PCC may reflect the emotional message control in patient group. This study facilitated understanding of the underlying neuropathological process in patients with pulsatile tinnitus.

  7. Abnormal resting-state functional connectivity study in unilateral pulsatile tinnitus patients with single etiology: A seed-based functional connectivity study

    International Nuclear Information System (INIS)

    Lv, Han; Zhao, Pengfei; Liu, Zhaohui; Li, Rui; Zhang, Ling; Wang, Peng; Yan, Fei; Liu, Liheng; Wang, Guopeng; Zeng, Rong; Li, Ting; Dong, Cheng; Gong, Shusheng; Wang, Zhenchang

    2016-01-01

    Objective: Previous studies demonstrated altered regional neural activations in several brain areas in patients with pulsatile tinnitus (PT), especially indicating an important role of posterior cingulate cortex (PCC). However, few studies focused on the degree of functional connectivity (FC) of this area in PT patients. In this study, we will compare the FC of PCC in patients affected with this condition and normal controls by using resting-state functional magnetic resonance imaging (fMRI). Methods: Structural and functional MRI data were obtained from 36 unilateral PT patients with single etiology and 36 matched healthy controls. FC feature of the region of interest (PCC) were characterized using a seed-based correlation method with the voxels in the whole-brain. Results: Compared with healthy controls, patients showed significant decreased FC to the right middle temporal gyrus (MTG), right thalamus and bilateral insula. By contrast, PCC demonstrated increased functional connectivity between the precuneus, bilateral inferior parietal lobule and middle occipital gyrus. We also found correlations between the disease duration of PT and FC of PCC-right MTG (r = −0.616, p < 0.001). Conclusions: Unilateral PT patients could have abnormal FC to the PCC bilaterally in the brain. PCC, as a highly integrated brain area, is an example of nucleus that was involved in mediation between different neural networks. It might be a modulation core between visual network and auditory network. The decreased FC of MTG to PCC may indicate a down regulation of activity between PCC and auditory associated brain cortex. Decreased FC between limbic system (bilateral AI) and PCC may reflect the emotional message control in patient group. This study facilitated understanding of the underlying neuropathological process in patients with pulsatile tinnitus.

  8. Sellafield (release of radioactivity)

    Energy Technology Data Exchange (ETDEWEB)

    Cunningham, J; Goodlad, A; Morris, M

    1986-02-06

    A government statement is reported, about the release of plutonium nitrate at the Sellafield site of British Nuclear Fuels plc on 5 February 1986. Matters raised included: details of accident; personnel monitoring; whether radioactive material was released from the site; need for public acceptance of BNFL activities; whether plant should be closed; need to reduce level of radioactive effluent; number of incidents at the plant.

  9. Aging and repeated thought suppression success.

    Directory of Open Access Journals (Sweden)

    Ann E Lambert

    Full Text Available Intrusive thoughts and attempts to suppress them are common, but while suppression may be effective in the short-term, it can increase thought recurrence in the long-term. Because intentional suppression involves controlled processing, and many aspects of controlled processing decline with age, age differences in thought suppression outcomes may emerge, especially over repeated thought suppression attempts as cognitive resources are expended. Using multilevel modeling, we examined age differences in reactions to thought suppression attempts across four thought suppression sequences in 40 older and 42 younger adults. As expected, age differences were more prevalent during suppression than during free monitoring periods, with younger adults indicating longer, more frequent thought recurrences and greater suppression difficulty. Further, younger adults' thought suppression outcomes changed over time, while trajectories for older adults' were relatively stable. Results are discussed in terms of older adults' reduced thought recurrence, which was potentially afforded by age-related changes in reactive control and distractibility.

  10. Accentuation-suppression and scaling

    DEFF Research Database (Denmark)

    Sørensen, Thomas Alrik; Bundesen, Claus

    2012-01-01

    The limitations of the visual short-term memory (VSTM) system have become an increasingly popular field of study. One line of inquiry has focused on the way attention selects objects for encoding into VSTM. Using the framework of the Theory of Visual Attention (TVA; Bundesen, 1990 Psychological...... a scaling mechanism modulating the decision bias of the observer and also through an accentuation-suppression mechanism that modulates the degree of subjective relevance of objects, contracting attention around fewer, highly relevant objects while suppressing less relevant objects. These mechanisms may...

  11. Microscopic bubble behaviour in suppression pool during wetwell venting

    Science.gov (United States)

    Zablackaite, G.; Nagasaka, H.; Kikura, H.

    2017-10-01

    During a severe accident PCV failure should be avoided and fission products inside PCV should be confined as much as possible. In order to minimize FPs release, Wetwell venting is conducted by releasing steam-non-condensable gas mixture carrying FPs from the Drywell to Suppression Pool. Steam is condensed by subcooled water in the pool, and most of FPs are retained into water. The removal of FP in the water pool is referred to as “Pool Scrubbing effect”. Hydrodynamic parameters of bubbles have impact on pool scrubbing effect. However, there is only few data available to evaluate quantitatively the bubble behaviour under depressurization and/or thermal stratification conditions. Series of experiments were conducted to evaluate the influence of temperature distribution, non-condensable gas content and pressure in the Wetwell on bubble behaviour. Bubbles were visualized using High Speed Camera and adopting shadowgraphy technique. Applying Particle Tracking Velocimetry, bubble velocity and size distribution were obtained from recorded images. Experimental results show that with increasing suppression pool temperature, bubbles reaching the pool surface decreased in size and traveling velocity became slower. In pressurized wetwell, bubble behaviour was similar to that in the heated up suppression pool case, although bubble parameters were similar to the low temperature case. Higher air content induced water surface movement and bubbles were smaller due to break up.

  12. ATP Release Channels

    Directory of Open Access Journals (Sweden)

    Akiyuki Taruno

    2018-03-01

    Full Text Available Adenosine triphosphate (ATP has been well established as an important extracellular ligand of autocrine signaling, intercellular communication, and neurotransmission with numerous physiological and pathophysiological roles. In addition to the classical exocytosis, non-vesicular mechanisms of cellular ATP release have been demonstrated in many cell types. Although large and negatively charged ATP molecules cannot diffuse across the lipid bilayer of the plasma membrane, conductive ATP release from the cytosol into the extracellular space is possible through ATP-permeable channels. Such channels must possess two minimum qualifications for ATP permeation: anion permeability and a large ion-conducting pore. Currently, five groups of channels are acknowledged as ATP-release channels: connexin hemichannels, pannexin 1, calcium homeostasis modulator 1 (CALHM1, volume-regulated anion channels (VRACs, also known as volume-sensitive outwardly rectifying (VSOR anion channels, and maxi-anion channels (MACs. Recently, major breakthroughs have been made in the field by molecular identification of CALHM1 as the action potential-dependent ATP-release channel in taste bud cells, LRRC8s as components of VRACs, and SLCO2A1 as a core subunit of MACs. Here, the function and physiological roles of these five groups of ATP-release channels are summarized, along with a discussion on the future implications of understanding these channels.

  13. Effect of methylmercury on histamine release from rat mast cells

    Energy Technology Data Exchange (ETDEWEB)

    Graevskaya, Elizabeth E.; Rubin, Andrew B. [Moscow State University, Biological Faculty, Department of Biophysics, 119899, Vorobjovy Gory, Moscow (Russian Federation); Yasutake, Akira; Aramaki, Ryoji [National Institute for Minamata Disease, 4058-18 Hama, Minamata, Kumamoto 867-0008 (Japan)

    2003-01-01

    Methylmercury chloride (MeHgCl) is well known as a significant environmental hazard, particularly as a modulator of the immune system. As it is acknowledged that the critical effector cells in the host response participating in various biological responses are mast cells, we tried to define the possible contribution of mast cells in the development of methylmercury-evoked effects. We investigated the effects of methylmercury on the rat mast cell degranulation induced by non-immunological stimuli (the selective liberator of histamine, compound 48/80, and calcium ionophore A23187) both in vivo and in vitro. Using the cells prepared from methylmercury-intoxicated rats through a 5-day treatment of MeHgCl (10 mg/kg/day), we observed the suppression of calcium ionophore A23187- and 48/80-induced histamine release, which was enhanced with time after treatment. Similar suppression was observed in the ionophore-stimulated release, when cells were prepared from rat with a single treatment of MeHgCl (20 mg/kg). It should be noted that when cells from the control rat were pre-incubated with methylmercury in vitro at a 10{sup -8} M concentration for 10 min, A23187 and compound 48/80-stimulated histamine release was significantly enhanced. However, when the pre-incubation period was prolonged to 30 min, the release was suppressed. An increase in the methylmercury concentration to 10{sup -6} M also suppressed the histamine release. These results show that methylmercury treatment can modify mast cell function depending on concentration and time, and might provide an insight into the role of mast cells in the development of methylmercury-stimulated effects. (orig.)

  14. Distinguishing among potential mechanisms of singleton suppression.

    Science.gov (United States)

    Gaspelin, Nicholas; Luck, Steven J

    2018-04-01

    Previous research has revealed that people can suppress salient stimuli that might otherwise capture visual attention. The present study tests between 3 possible mechanisms of visual suppression. According to first-order feature suppression models , items are suppressed on the basis of simple feature values. According to second-order feature suppression models , items are suppressed on the basis of local discontinuities within a given feature dimension. According to global-salience suppression models , items are suppressed on the basis of their dimension-independent salience levels. The current study distinguished among these models by varying the predictability of the singleton color value. If items are suppressed by virtue of salience alone, then it should not matter whether the singleton color is predictable. However, evidence from probe processing and eye movements indicated that suppression is possible only when the color values are predictable. Moreover, the ability to suppress salient items developed gradually as participants gained experience with the feature that defined the salient distractor. These results are consistent with first-order feature suppression models, and are inconsistent with the other models of suppression. In other words, people primarily suppress salient distractors on the basis of their simple features and not on the basis of salience per se. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  15. Consequences of stereotype suppression and internal suppression motivation : A self-regulation approach

    NARCIS (Netherlands)

    Gordijn, Ernestine H; Hindriks, Inge; Koomen, W; Dijksterhuis, Ap; van Knipppenberg, A.

    The present research studied the effects of suppression of stereotypes on subsequent stereotyping. Moreover, the moderating influence of motivation to suppress stereotypes was examined. The first three experiments showed that suppression of stereotypes leads to the experience of engaging in

  16. RAVEN Beta Release

    International Nuclear Information System (INIS)

    Rabiti, Cristian; Alfonsi, Andrea; Cogliati, Joshua Joseph; Mandelli, Diego; Kinoshita, Robert Arthur; Wang, Congjian; Maljovec, Daniel Patrick; Talbot, Paul William

    2016-01-01

    This documents the release of the Risk Analysis Virtual Environment (RAVEN) code. A description of the RAVEN code is provided, and discussion of the release process for the M2LW-16IN0704045 milestone. The RAVEN code is a generic software framework to perform parametric and probabilistic analysis based on the response of complex system codes. RAVEN is capable of investigating the system response as well as the input space using Monte Carlo, Grid, or Latin Hyper Cube sampling schemes, but its strength is focused toward system feature discovery, such as limit surfaces, separating regions of the input space leading to system failure, using dynamic supervised learning techniques. RAVEN has now increased in maturity enough for the Beta 1.0 release.

  17. RAVEN Beta Release

    Energy Technology Data Exchange (ETDEWEB)

    Rabiti, Cristian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Alfonsi, Andrea [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cogliati, Joshua Joseph [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mandelli, Diego [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kinoshita, Robert Arthur [Idaho National Lab. (INL), Idaho Falls, ID (United States); Wang, Congjian [Idaho National Lab. (INL), Idaho Falls, ID (United States); Maljovec, Daniel Patrick [Idaho National Lab. (INL), Idaho Falls, ID (United States); Talbot, Paul William [Idaho National Lab. (INL), Idaho Falls, ID (United States)

    2016-02-01

    This documents the release of the Risk Analysis Virtual Environment (RAVEN) code. A description of the RAVEN code is provided, and discussion of the release process for the M2LW-16IN0704045 milestone. The RAVEN code is a generic software framework to perform parametric and probabilistic analysis based on the response of complex system codes. RAVEN is capable of investigating the system response as well as the input space using Monte Carlo, Grid, or Latin Hyper Cube sampling schemes, but its strength is focused toward system feature discovery, such as limit surfaces, separating regions of the input space leading to system failure, using dynamic supervised learning techniques. RAVEN has now increased in maturity enough for the Beta 1.0 release.

  18. BWR Mark III pressure suppression containment response to hydrogen deflagration

    International Nuclear Information System (INIS)

    Fuls, G.M.; Gunter, A.D.

    1982-01-01

    The CLASIX-3 computer program has been used to evaluate the temperature and pressure response of the BWR Mark III Suppression Containment System to hydrogen deflagration resulting from a degraded core condition. The CLASIX-3 computer program is an extension of the CLASIX program which was originally developed to analyze ice condenser containments. A brief description is given of the modifications made to CLASIX to increase its flexibility and versatility to include the capability of analyzing the Mark III Containment. Analytical results are presented for the two base case transients. The two base cases are the stuck open steam relief valve and the small break LOCA, both of which are assumed to lead to a degraded core condition and the release of hydrogen to the containment. Results include pressure and temperature response, gas concentrations and suppression pool response

  19. Suppression and repression: A theoretical discussion illustrated by a movie

    Directory of Open Access Journals (Sweden)

    Maria Lucia de Souza Campos Paiva

    2012-02-01

    Full Text Available The first translations of Freud's work into Portuguese have presented problems because they were not translated from the German language. More than a hundred years after the beginning of Psychoanalysis, there are still many discussions on Freud's metapsychology and a considerable difficulty in obtaining a consensus on the translation of some concepts. This paper refers back to Freud's concepts of primal repression, repression and suppression. In order to discuss such concepts, we have made use of a film, co-produced by Germans and Argentineans, which is named "The Song in me" (Das Lied in mir, released to the public in 2011 and directed by Florian Micoud Cossen. Through this motion picture, the following of Freud's concepts are analyzed, and the differentiation between them is discussed: suppression and repression, as well as the importance of their precise translation.

  20. Simultaneous initiation of degranulation and inhibition of leukotriene release by soman in human basophils

    Energy Technology Data Exchange (ETDEWEB)

    Meier, H.L.; Warner, J.; MacGlashan, D.W.

    1995-12-31

    Previous studies noted that the serine esterase inhibitor, soman, could induce histamine release from human basophils. To investigate the mechanisms by which soman causes histamine release (a preformed mediator), we also examined its ability to induce leukotriene release (a newly synthesized mediator) from basophils. We found that no leukotriene release followed activation with soman, while histamine release was usually greater than 70%. In addition, soman and diisopropyl-fluorophosphate were found actively to suppress low level spontaneous leukotriene release as well as ongoing leukotriene release induced by anti-IgE antibody. Soman (0.3 mM) was able to stop leukotriene release as rapidly as the calcium chelator, EDTA. In a series of control experiments, it was noted that soman did not influence the metabolism of LTC4 to LTD4 or LTE4 (for which little metabolism occurred), eliminating the possibility that reduced LTC4 release could have resulted from its enhanced metabolism. Therefore, using one compound (soman), basophils could be simultaneously activated to degranulate while having the pathway leading to leukotriene release actively suppressed. These results provide further evidence that histamine and leukotriene release are independent pathways resulting from the activation of basophils.

  1. Assessing the efficiency of Wolbachia driven Aedes mosquito suppression by delay differential equations.

    Science.gov (United States)

    Huang, Mugen; Luo, Jiaowan; Hu, Linchao; Zheng, Bo; Yu, Jianshe

    2017-12-14

    To suppress wild population of Aedes mosquitoes, the primary transmission vector of life-threatening diseases such as dengue, malaria, and Zika, an innovative strategy is to release male mosquitoes carrying the bacterium Wolbachia into natural areas to drive female sterility by cytoplasmic incompatibility. We develop a model of delay differential equations, incorporating the strong density restriction in the larval stage, to assess the delicate impact of life table parameters on suppression efficiency. Through mathematical analysis, we find the sufficient and necessary condition for global stability of the complete suppression state. This condition, combined with the experimental data for Aedes albopictus population in Guangzhou, helps us predict a large range of releasing intensities for suppression success. In particular, we find that if the number of released infected males is no less than four times the number of mosquitoes in wild areas, then the mosquito density in the peak season can be reduced by 95%. We introduce an index to quantify the dependence of suppression efficiency on parameters. The invariance of some quantitative properties of the index values under various perturbations of the same parameter justifies the applicability of this index, and the robustness of our modeling approach. The index yields a ranking of the sensitivity of all parameters, among which the adult mortality has the highest sensitivity and is considerably more sensitive than the natural larvae mortality. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Installation for the suppression of sodium fires

    International Nuclear Information System (INIS)

    Newman, R.N.; Payne, J.F.B.; Lee, C.J.; Rowe, D.M.J.

    1979-01-01

    The basic operating principles are discussed of a passive baffle-catch tray fire suppression system for sodium fires. A new design is described incorporating increased compartmentalization of the collecting and drainage parts of the device. The burning and smoke generation rates from trays with varying aperture sizes were measured. From the experiments it was found that the burning rate and smoke generation rates could be related satisfactorily to the aperture areas. For the smallest aperture size ( 2 ) it was found that the smoke release was considerably less than that from a fire of the same area, because the smoke deposited on the underside of the baffle. A re-ignition problem was found, where pillars of sodium oxide (wicks) grow upward from the surface of the drained sodium and begin to burn when level with the baffle aperature. From a knowledge of the rate of growth of the wicks, trays may be made sufficiently deep to avoid the problem. Self acting valves were developed which allow the passage of sodium through the aperture and close when drainage is complete. These devices were shown to effect complete extinction of the drained sodium. Using the designs proposed it is possible to construct a system that will reduce the smoke emission from the drained sodium by a factor approaching 10 3 , without the use of valves, or with the self acting valves developed, reduce the emission from the drained sodium to approximately zero. (author)

  3. Suppression of stratified explosive interactions

    Energy Technology Data Exchange (ETDEWEB)

    Meeks, M.K.; Shamoun, B.I.; Bonazza, R.; Corradini, M.L. [Wisconsin Univ., Madison, WI (United States). Dept. of Nuclear Engineering and Engineering Physics

    1998-01-01

    Stratified Fuel-Coolant Interaction (FCI) experiments with Refrigerant-134a and water were performed in a large-scale system. Air was uniformly injected into the coolant pool to establish a pre-existing void which could suppress the explosion. Two competing effects due to the variation of the air flow rate seem to influence the intensity of the explosion in this geometrical configuration. At low flow rates, although the injected air increases the void fraction, the concurrent agitation and mixing increases the intensity of the interaction. At higher flow rates, the increase in void fraction tends to attenuate the propagated pressure wave generated by the explosion. Experimental results show a complete suppression of the vapor explosion at high rates of air injection, corresponding to an average void fraction of larger than 30%. (author)

  4. Strangeness Suppression and Color Deconfinement

    Science.gov (United States)

    Satz, Helmut

    2018-02-01

    The relative multiplicities for hadron production in different high energy collisions are in general well described by an ideal gas of all hadronic resonances, except that under certain conditions, strange particle rates are systematically reduced. We show that the suppression factor γs, accounting for reduced strange particle rates in pp, pA and AA collisions at different collision energies, becomes a universal function when expressed in terms of the initial entropy density s0 or the initial temperature T of the produced thermal medium. It is found that γs increases from about 0.5 to 1.0 in a narrow temperature range around the quark-hadron transition temperature Tc ≃ 160 MeV. Strangeness suppression thus disappears with the onset of color deconfinement; subsequently, full equilibrium resonance gas behavior is attained.

  5. Hydraulic release oil tool

    International Nuclear Information System (INIS)

    Mims, M.G.; Mueller, M.D.; Ehlinger, J.C.

    1992-01-01

    This patent describes a hydraulic release tool. It comprises a setting assembly; a coupling member for coupling to drill string or petroleum production components, the coupling member being a plurality of sockets for receiving the dogs in the extended position and attaching the coupling member the setting assembly; whereby the setting assembly couples to the coupling member by engagement of the dogs in the sockets of releases from and disengages the coupling member in movement of the piston from its setting to its reposition in response to a pressure in the body in exceeding the predetermined pressure; and a relief port from outside the body into its bore and means to prevent communication between the relief port and the bore of the body axially of the piston when the piston is in the setting position and to establish such communication upon movement of the piston from the setting position to the release position and reduce the pressure in the body bore axially of the piston, whereby the reduction of the pressure signals that the tool has released the coupling member

  6. APASS Data Release 10

    Science.gov (United States)

    Henden, Arne A.; Levine, Stephen; Terrell, Dirk; Welch, Douglas L.; Munari, Ulisse; Kloppenborg, Brian K.

    2018-06-01

    The AAVSO Photometric All-Sky Survey (APASS) has been underway since 2010. This survey covers the entire sky from 7.5 knowledge of the optical train distortions. With these changes, DR10 includes many more stars than prior releases. We describe the survey, its remaining limitations, and prospects for the future, including a very-bright-star extension.

  7. Release the Prisoners Game

    Science.gov (United States)

    Van Hecke, Tanja

    2011-01-01

    This article presents the mathematical approach of the optimal strategy to win the "Release the prisoners" game and the integration of this analysis in a math class. Outline lesson plans at three different levels are given, where simulations are suggested as well as theoretical findings about the probability distribution function and its mean…

  8. Chk1 suppressed cell death

    Directory of Open Access Journals (Sweden)

    Meuth Mark

    2010-09-01

    Full Text Available Abstract The role of Chk1 in the cellular response to DNA replication stress is well established. However recent work indicates a novel role for Chk1 in the suppression of apoptosis following the disruption of DNA replication or DNA damage. This review will consider these findings in the context of known pathways of Chk1 signalling and potential applications of therapies that target Chk1.

  9. Puberty suppression in adolescents with gender identity disorder: a prospective follow-up study

    NARCIS (Netherlands)

    de Vries, A.L.C.; Steensma, T.D.; Doreleijers, T.A.H.; Cohen-Kettenis, P.T.

    2011-01-01

    Introduction. Puberty suppression by means of gonadotropin-releasing hormone analogues (GnRHa) is used for young transsexuals between 12 and 16 years of age. The purpose of this intervention is to relieve the suffering caused by the development of secondary sex characteristics and to provide time to

  10. Puberty suppression and executive functioning : An fMRI-study in adolescents with gender dysphoria

    NARCIS (Netherlands)

    Staphorsius, Annemieke S; Kreukels, Baudewijntje P C; Cohen-Kettenis, Peggy T; Veltman, Dick J; Burke, Sarah M; Schagen, Sebastian E E; Wouters, Femke M; Delemarre-van de Waal, Henriëtte A; Bakker, J.

    Adolescents with gender dysphoria (GD) may be treated with gonadotropin releasing hormone analogs (GnRHa) to suppress puberty and, thus, the development of (unwanted) secondary sex characteristics. Since adolescence marks an important period for the development of executive functioning (EF), we

  11. Puberty suppression and executive functioning: An fMRI-study in adolescents with gender dysphoria

    NARCIS (Netherlands)

    Staphorsius, A.S.; Kreukels, B.P.C.; Cohen-Kettenis, P.T.; Veltman, D.J.; Burke, S.M.; Schagen, S.E.E.; Wouters, F.M.; Delemarre-van de Waal, H.A.; Bakker, J.

    2015-01-01

    Adolescents with gender dysphoria (GD) may be treated with gonadotropin releasing hormone analogs (GnRHa) to suppress puberty and, thus, the development of (unwanted) secondary sex characteristics. Since adolescence marks an important period for the development of executive functioning (EF), we

  12. Perceptions of Sex, Gender, and Puberty Suppression: A Qualitative Analysis of Transgender Youth

    NARCIS (Netherlands)

    Vrouenraets, L.J.; Fredriks, A.M.; Hannema, S.E.; Cohen-Kettenis, P.T.; Vries, M.C. de

    2016-01-01

    International guidelines recommend the use of Gonadotropin-Releasing Hormone (GnRH) agonists in adolescents with gender dysphoria (GD) to suppress puberty. Little is known about the way gender dysphoric adolescents themselves think about this early medical intervention. The purpose of the present

  13. In-Flight Suppressant Deployment Temperatures

    National Research Council Canada - National Science Library

    Bein, Donald

    2006-01-01

    .... An assessment is made of the model output versus some aircraft measurement data, fire suppressant boiling point criterion, as well as the history of altitude/temperature at which fire suppressants have been deployed...

  14. Zinc release from Schaffer collaterals and its significance.

    Science.gov (United States)

    Takeda, Atsushi; Nakajima, Satoko; Fuke, Sayuri; Sakurada, Naomi; Minami, Akira; Oku, Naoto

    2006-02-15

    On the basis of the evidence that approximately 45% of Schaffer collateral boutons are zinc-positive, zinc release from Schaffer collaterals and its action were examined in hippocampal slices. When zinc release from Schaffer collaterals was examined using ZnAF-2, a membrane-impermeable zinc indicator, ZnAF-2 signal in the stratum radiatum of the CA1 was increased by tetanic stimuli at 100 Hz for 1s, suggesting that zinc is released from Schaffer collaterals in a calcium- and impulse-dependent manner. An in vivo microdialysis experiment indicated that the perfusion with 10 microM zinc significantly decreases extracellular glutamate concentration in the CA1. When tetanic stimuli at 100 Hz for 5s were delivered to the dentate granule cells, the increase in calcium signal in the stratum radiatum of the CA1, as well as in the stratum lucidum of the CA3, was attenuated by addition of 10 microM zinc, while enhanced by addition of 1mM CaEDTA, a membrane-impermeable zinc chelator. The increase in calcium signal in the CA1, in which Schaffer collateral synapses exist, during delivery of tetanic stimuli at 100 Hz for 1s to the Schaffer collateral-commissural pathway was also significantly enhanced by addition of 1mM CaEDTA. These results suggest that zinc released from Schaffer collaterals suppressively modulates presynaptic and postsynaptic calcium signaling in the CA1, followed by the suppression of glutamate release.

  15. In the suppression of regge cut contributions

    International Nuclear Information System (INIS)

    Chia, S.P.

    1975-07-01

    It is shown that contributions of reggeon-pomeron cuts are suppressed in amplitudes with opposite natural to the reggeon. This suppression grows logarithmically with energy. The suppression in the πP cut is, however, found to be weak. Consequence on conspiracy is discussed

  16. Spatial-temporal three-dimensional ultrasound plane-by-plane active cavitation mapping for high-intensity focused ultrasound in free field and pulsatile flow.

    Science.gov (United States)

    Ding, Ting; Hu, Hong; Bai, Chen; Guo, Shifang; Yang, Miao; Wang, Supin; Wan, Mingxi

    2016-07-01

    Cavitation plays important roles in almost all high-intensity focused ultrasound (HIFU) applications. However, current two-dimensional (2D) cavitation mapping could only provide cavitation activity in one plane. This study proposed a three-dimensional (3D) ultrasound plane-by-plane active cavitation mapping (3D-UPACM) for HIFU in free field and pulsatile flow. The acquisition of channel-domain raw radio-frequency (RF) data in 3D space was performed by sequential plane-by-plane 2D ultrafast active cavitation mapping. Between two adjacent unit locations, there was a waiting time to make cavitation nuclei distribution of the liquid back to the original state. The 3D cavitation map equivalent to the one detected at one time and over the entire volume could be reconstructed by Marching Cube algorithm. Minimum variance (MV) adaptive beamforming was combined with coherence factor (CF) weighting (MVCF) or compressive sensing (CS) method (MVCS) to process the raw RF data for improved beamforming or more rapid data processing. The feasibility of 3D-UPACM was demonstrated in tap-water and a phantom vessel with pulsatile flow. The time interval between temporal evolutions of cavitation bubble cloud could be several microseconds. MVCF beamformer had a signal-to-noise ratio (SNR) at 14.17dB higher, lateral and axial resolution at 2.88times and 1.88times, respectively, which were compared with those of B-mode active cavitation mapping. MVCS beamformer had only 14.94% time penalty of that of MVCF beamformer. This 3D-UPACM technique employs the linear array of a current ultrasound diagnosis system rather than a 2D array transducer to decrease the cost of the instrument. Moreover, although the application is limited by the requirement for a gassy fluid medium or a constant supply of new cavitation nuclei that allows replenishment of nuclei between HIFU exposures, this technique may exhibit a useful tool in 3D cavitation mapping for HIFU with high speed, precision and resolution

  17. Decontamination for free release

    Energy Technology Data Exchange (ETDEWEB)

    Simpson, K A; Elder, G R [Bradtec Ltd., Bristol (United Kingdom)

    1997-02-01

    Many countries are seeking to treat radioactive waste in ways which meet the local regulatory requirements, but yet are cost effective when all contributing factors are assessed. In some countries there are increasing amounts of waste, arising from nuclear plant decommissioning, which are categorized as low level waste: however with suitable treatment a large part of such wastes might become beyond regulatory control and be able to be released as non-radioactive. The benefits and disadvantages of additional treatment before disposal need to be considered. Several processes falling within the overall description of decontamination for free release have been developed and applied, and these are outlined. In one instance the process seeks to take advantage of techniques and equipment used for decontaminating water reactor circuits intermittently through reactor life. (author). 9 refs, 1 fig., 3 tabs.

  18. Atmospheric Release Advisory Capability

    International Nuclear Information System (INIS)

    Dickerson, M.H.; Gudiksen, P.H.; Sullivan, T.J.

    1983-02-01

    The Atmospheric Release Advisory Capability (ARAC) project is a Department of Energy (DOE) sponsored real-time emergency response service available for use by both federal and state agencies in case of a potential or actual atmospheric release of nuclear material. The project, initiated in 1972, is currently evolving from the research and development phase to full operation. Plans are underway to expand the existing capability to continuous operation by 1984 and to establish a National ARAC Center (NARAC) by 1988. This report describes the ARAC system, its utilization during the past two years, and plans for its expansion during the next five to six years. An integral part of this expansion is due to a very important and crucial effort sponsored by the Defense Nuclear Agency to extend the ARAC service to approximately 45 Department of Defense (DOD) sites throughout the continental US over the next three years

  19. Border cell release

    DEFF Research Database (Denmark)

    Mravec, Jozef

    2017-01-01

    Plant border cells are specialised cells derived from the root cap with roles in the biomechanics of root growth and in forming a barrier against pathogens. The mechanism of highly localised cell separation which is essential for their release to the environment is little understood. Here I present...... in situ analysis of Brachypodium distachyon, a model organism for grasses which possess type II primary cell walls poor in pectin content. Results suggest similarity in spatial dynamics of pectic homogalacturonan during dicot and monocot border cell release. Integration of observations from different...... species leads to the hypothesis that this process most likely does not involve degradation of cell wall material but rather employs unique cell wall structural and compositional means enabling both the rigidity of the root cap as well as detachability of given cells on its surface....

  20. Energy released in fission

    International Nuclear Information System (INIS)

    James, M.F.

    1969-05-01

    The effective energy released in and following the fission of U-235, Pu-239 and Pu-241 by thermal neutrons, and of U-238 by fission spectrum neutrons, is discussed. The recommended values are: U-235 ... 192.9 ± 0.5 MeV/fission; U-238 ... 193.9 ± 0.8 MeV/fission; Pu-239 ... 198.5 ± 0.8 MeV/fission; Pu-241 ... 200.3 ± 0.8 MeV/fission. These values include all contributions except from antineutrinos and very long-lived fission products. The detailed contributions are discussed, and inconsistencies in the experimental data are pointed out. In Appendix A, the contribution to the total useful energy release in a reactor from reactions other than fission are discussed briefly, and in Appendix B there is a discussion of the variations in effective energy from fission with incident neutron energy. (author)

  1. Slow-release fertilizer

    Science.gov (United States)

    Ming, Douglas W.; Golden, D. C.

    1992-10-01

    A synthetic apatite containing agronutrients and a method for making the apatite are disclosed. The apatite comprises crystalline calcium phosphate having agronutrients dispersed in the crystalline structure. The agronutrients can comprise potassium, magnesium, sulfur, iron, manganese, molybdenum, chlorine, boron, copper and zinc in amounts suited for plant growth. The apatite can optionally comprise a carbonate and/or silicon solubility control agent. The agronutrients are released slowly as the apatite dissolves.

  2. EIA new releases

    International Nuclear Information System (INIS)

    1994-12-01

    This report was prepared by the Energy Information Administration. It contains news releases on items of interest to the petroleum, coal, nuclear, electric and alternate fuels industries ranging from economic outlooks to environmental concerns. There is also a listing of reports by industry and an energy education resource listing containing sources for free or low-cost energy-related educational materials for educators and primary and secondary students

  3. Atmospheric release advisory capability

    International Nuclear Information System (INIS)

    Sullivan, T.J.

    1981-01-01

    The ARAC system (Atmospheric Release Advisory Capability) is described. The system is a collection of people, computers, computer models, topographic data and meteorological input data that together permits a calculation of, in a quasi-predictive sense, where effluent from an accident will migrate through the atmosphere, where it will be deposited on the ground, and what instantaneous and integrated dose an exposed individual would receive

  4. Slow-release fertilizer

    Science.gov (United States)

    Ming, Douglas W. (Inventor); Golden, Dadigamuwage C. (Inventor)

    1995-01-01

    A synthetic apatite containing agronutrients and a method for making the apatite are disclosed. The apatite comprises crystalline calcium phosphate having agronutrients dispersed in the crystalline structure. The agronutrients can comprise potassium, magnesium, sulfur, iron, manganese, molybdenum, chlorine, boron, copper and zinc in amounts suited for plant growth. The apatite can optionally comprise a carbonate and/or silicon solubility control agent. The agronutrients are released slowly as the apatite dissolves.

  5. Corticotropin-releasing hormone induces depression-like changes of sleep electroencephalogram in healthy women.

    Science.gov (United States)

    Schüssler, P; Kluge, M; Gamringer, W; Wetter, T C; Yassouridis, A; Uhr, M; Rupprecht, R; Steiger, A

    2016-12-01

    We reported previously that repetitive intravenous injections of corticotropin-releasing hormone (CRH) around sleep onset prompt depression-like changes in certain sleep and endocrine activity parameters (e.g. decrease of slow-wave sleep during the second half of the night, blunted growth hormone peak, elevated cortisol concentration during the first half of the night). Furthermore a sexual dimorphism of the sleep-endocrine effects of the hormones growth hormone-releasing hormone and ghrelin was observed. In the present placebo-controlled study we investigated the effect of pulsatile administration of 4×50μg CRH on sleep electroencephalogram (EEG) and nocturnal cortisol and GH concentration in young healthy women. After CRH compared to placebo, intermittent wakefulness increased during the total night and the sleep efficiency index decreased. During the first third of the night, REM sleep and stage 2 sleep increased and sleep stage 3 decreased. Cortisol concentration was elevated throughout the night and during the first and second third of the night. GH secretion remained unchanged. Our data suggest that after CRH some sleep and endocrine activity parameters show also depression-like changes in healthy women. These changes are more distinct in women than in men. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Contact: Releasing the news

    Science.gov (United States)

    Pinotti, Roberto

    The problem of mass behavior after man's future contacts with other intelligences in the universe is not only a challenge for social scientists and political leaders all over the world, but also a cultural time bomb as well. In fact, since the impact of CETI (Contact with Extraterrestrial Intelligence) on human civilization, with its different cultures, might cause a serious socio-anthropological shock, a common and predetermined worldwide strategy is necessary in releasing the news after the contact, in order to keep possible manifestations of fear, panic and hysteria under control. An analysis of past studies in this field and of parallel historical situations as analogs suggests a definite "authority crisis" in the public as a direct consequence of an unexpected release of the news, involving a devastating "chain reaction" process (from both the psychological and sociological viewpoints) of anomie and maybe the collapse of today's society. The only way to prevent all this is to prepare the world's public opinion concerning contact before releasing the news, and to develop a long-term strategy through the combined efforts of scientists, political leaders, intelligence agencies and the mass media, in order to create the cultural conditions in which a confrontation with ETI won't affect mankind in a traumatic way. Definite roles and tasks in this multi-level model are suggested.

  7. Palmitoylethanolamide Inhibits Glutamate Release in Rat Cerebrocortical Nerve Terminals

    Directory of Open Access Journals (Sweden)

    Tzu-Yu Lin

    2015-03-01

    Full Text Available The effect of palmitoylethanolamide (PEA, an endogenous fatty acid amide displaying neuroprotective actions, on glutamate release from rat cerebrocortical nerve terminals (synaptosomes was investigated. PEA inhibited the Ca2+-dependent release of glutamate, which was triggered by exposing synaptosomes to the potassium channel blocker 4-aminopyridine. This release inhibition was concentration dependent, associated with a reduction in cytosolic Ca2+ concentration, and not due to a change in synaptosomal membrane potential. The glutamate release-inhibiting effect of PEA was prevented by the Cav2.1 (P/Q-type channel blocker ω-agatoxin IVA or the protein kinase A inhibitor H89, not affected by the intracellular Ca2+ release inhibitors dantrolene and CGP37157, and partially antagonized by the cannabinoid CB1 receptor antagonist AM281. Based on these results, we suggest that PEA exerts its presynaptic inhibition, likely through a reduction in the Ca2+ influx mediated by Cav2.1 (P/Q-type channels, thereby inhibiting the release of glutamate from rat cortical nerve terminals. This release inhibition might be linked to the activation of presynaptic cannabinoid CB1 receptors and the suppression of the protein kinase A pathway.

  8. Peptide secreted by human alveolar macrophages releases neutrophil granule contents

    International Nuclear Information System (INIS)

    MacArthur, C.K.; Miller, E.J.; Cohen, A.B.

    1987-01-01

    A monoclonal antibody was developed against an 8000-kDa enzyme-releasing peptide (ERP) released from human alveolar macrophages. ERP was isolated on an immunoaffinity column containing the antibody bound to staphylococcal protein A-Sepharose, and by autoradiography. Release of ERP from the macrophages is not changed by plastic adherence, phagocytosis, calcium ionophore, or phorbol esters. The peptide was not antigenically similar to interferon-γ, tumor necrosis factor, or interleukin lα or 1β. The release of constituents from azurophilic and specific granules was the main identified biologic function of ERP. ERP was a more effective secretagogue in the untreated neutrophils and f-met-leu-phe was more effective in the cytochalasin B-treated neutrophils. Absorption of ERP from macrophage-conditioned medium removed a small amount of the chemotactic activity; however, the immunopurified peptide was not chemotactic or chemokinetic for neutrophils, and at high concentrations, it suppressed base line chemokinesis. Treatment of washed macrophages with trypsin released active ERP of approximately the same m.w. of spontaneously secreted ERP. These studies showed that human alveolar macrophages release a peptide which is a secretagogue for human neutrophils under conditions which may be encountered in the lungs during certain disease states. Proteolytic enzymes which are free in the lungs may release the peptide and lead to the secretion of neutrophil enzymes

  9. Suppress flashover of GRP fire with water mist inside ISO 9705 Room

    Directory of Open Access Journals (Sweden)

    Qiang Xu

    2011-01-01

    Full Text Available Water mist suppression tests for glass-reinforced polyester (GRP panels were conducted in ISO 9705 room. GRP panels covered part of the room and a wood crib fire was used as fire source to ignite GRP fire. A four-nozzle water mist suppression equipment was used inside test room on the time of flashover. Heat release rate of the combustion inside the room, room temperature, surface temperature of GRP panels, total heat flux to wall, ceiling and floor in specific positions were measured. Gas concentration of O2, CO, and CO2 was also measured in the corner of the room at two different levels. A thermal image video was used to record the suppression procedure inside room. Test results show that the water mist system is efficient in suppressing the flashover of GRP fire and cooling the room within short time.

  10. Polypyrrole Actuators for Tremor Suppression

    DEFF Research Database (Denmark)

    Skaarup, Steen; Mogensen, Naja; Bay, Lasse

    2003-01-01

    Neurological tremor affecting limbs can be divided into at least 6 different types with frequencies ranging from 2 to about 20 Hz. In order to alleviate the symptoms by suppressing the tremor, sensing and actuation systems able to perform at these frequencies are needed. Electroactive polymers...... exemplify 'soft actuator' technology that may be especially suitable for use in conjunction with human limbs. The electrochemical and mechanical properties of polypyrrole dodecyl benzene sulphonate actuator films have been studied with this application in mind. The results show that the time constants...

  11. Suppression effects on musical and verbal memory.

    Science.gov (United States)

    Schendel, Zachary A; Palmer, Caroline

    2007-06-01

    Three experiments contrasted the effects of articulatory suppression on recognition memory for musical and verbal sequences. In Experiment 1, a standard/comparison task was employed, with digit or note sequences presented visually or auditorily while participants remained silent or produced intermittent verbal suppression (saying "the") or musical suppression (singing "la"). Both suppression types decreased performance by equivalent amounts, as compared with no suppression. Recognition accuracy was lower during suppression for visually presented digits than during that for auditorily presented digits (consistent with phonological loop predictions), whereas accuracy was equivalent for visually presented notes and auditory tones. When visual interference filled the retention interval in Experiment 2, performance with visually presented notes but not digits was impaired. Experiment 3 forced participants to translate visually presented music sequences by presenting comparison sequences auditorily. Suppression effects for visually presented music resembled those for digits only when the recognition task required sensory translation of cues.

  12. Protecting privacy in data release

    CERN Document Server

    Livraga, Giovanni

    2015-01-01

    This book presents a comprehensive approach to protecting sensitive information when large data collections are released by their owners. It addresses three key requirements of data privacy: the protection of data explicitly released, the protection of information not explicitly released but potentially vulnerable due to a release of other data, and the enforcement of owner-defined access restrictions to the released data. It is also the first book with a complete examination of how to enforce dynamic read and write access authorizations on released data, applicable to the emerging data outsou

  13. Triggered Release from Polymer Capsules

    Energy Technology Data Exchange (ETDEWEB)

    Esser-Kahn, Aaron P. [Univ. of Illinois, Urbana, IL (United States). Beckman Inst. for Advanced Science and Technology and Dept. of Chemistry; Odom, Susan A. [Univ. of Illinois, Urbana, IL (United States). Beckman Inst. for Advanced Science and Technology and Dept. of Chemistry; Sottos, Nancy R. [Univ. of Illinois, Urbana, IL (United States). Beckman Inst. for Advanced Science and Technology and Dept. of Materials Science and Engineering; White, Scott R. [Univ. of Illinois, Urbana, IL (United States). Beckman Inst. for Advanced Science and Technology and Dept. of Aerospace Engineering; Moore, Jeffrey S. [Univ. of Illinois, Urbana, IL (United States). Beckman Inst. for Advanced Science and Technology and Dept. of Chemistry

    2011-07-06

    Stimuli-responsive capsules are of interest in drug delivery, fragrance release, food preservation, and self-healing materials. Many methods are used to trigger the release of encapsulated contents. Here we highlight mechanisms for the controlled release of encapsulated cargo that utilize chemical reactions occurring in solid polymeric shell walls. Triggering mechanisms responsible for covalent bond cleavage that result in the release of capsule contents include chemical, biological, light, thermal, magnetic, and electrical stimuli. We present methods for encapsulation and release, triggering methods, and mechanisms and conclude with our opinions on interesting obstacles for chemically induced activation with relevance for controlled release.

  14. High-flavanol and high-theobromine versus low-flavanol and low-theobromine chocolate to improve uterine artery pulsatility index: a double blind randomized clinical trial.

    Science.gov (United States)

    Bujold, Emmanuel; Leblanc, Vicky; Lavoie-Lebel, Élise; Babar, Asma; Girard, Mario; Poungui, Lionel; Blanchet, Claudine; Marc, Isabelle; Lemieux, Simone; Belkacem, Abdous; Sidi, Elhadji Laouan; Dodin, Sylvie

    2017-09-01

    To evaluate the impact of high-flavanol and high-theobromine (HFHT) chocolate in women at risk of preeclampsia (PE). We conducted a single-center randomized controlled trial including women with singleton pregnancy between 11 and 14 weeks gestation who had bilateral abnormal uterine artery (UtA) waveforms (notching) and elevated pulsatility index (PI). Participants were randomized to either HFHT or low-flavanol and low-theobromine (LFLT) chocolate (30 grams daily for a total of 12 weeks). UtA PI, reported as multiple of medians (MoM) adjusted for gestational age, was assessed at baseline and 12 weeks after randomization. One hundred thirty-one women were randomized with mean gestational age of 12.4 ± 0.6 weeks and a mean UtA PI of 1.39 ± 0.31 MoM. UtA PI adjusted for gestational age significantly decreased from baseline to the second visit (12 weeks later) in the two groups (p chocolate, daily intake of HFHT chocolate was not associated with significant changes of UtA PI. Nevertheless, the improvement observed in both groups suggests that chocolate could improve placental function independently of flavanol and/or theobromine content.

  15. Menstrual phase-related differences in the pulsatility index on the central retinal artery suggest an oestrogen vasodilatation effect that antagonizes with progesterone.

    Science.gov (United States)

    Viana, Luiz Carlos; Faria, Marcos; Pettersen, Heverton; Sampaio, Marcos; Geber, Selmo

    2011-03-01

    The actual effect of steroid hormones on cerebral microcirculation is still controversial. Therefore, the aim of our study was to investigate vascular flow variations in the central retinal artery that may exist during the ovulatory menstrual cycle. A total of 34 healthy women were included in this observational, longitudinal, and prospective study. All participants were submitted to dopplerfluxometric evaluation of the eyes in order to study the pulsatility index (PI) of the central retinal arteries, during four phases of the menstrual cycle: early follicular, mid follicular, periovulatory, and mid luteal phases. Subjects' ages ranged from 14 to 47 years old (mean: 29.7 ± 10.1) and PI did not differ among age groups. The PI of the central retinal artery was different among the four phases of the menstrual cycle. PI showed a significant decrease from early follicular phase (1.72) to mid follicular phase (1.57) (p = 0.037), and was similar during periovulatory phase (1.56) and significantly increased in mid luteal phase (1.70). After that it returned to the values observed in the early follicular phase. Our results suggest the existence of an oestrogen vasodilatation effect on the central retinal artery that is menstrual phase-related and antagonized by progesterone.

  16. Analysis of pulsatile retinal movements by spectral-domain low-coherence interferometry: influence of age and glaucoma on the pulse wave.

    Directory of Open Access Journals (Sweden)

    Carolyne Dion

    Full Text Available Recent studies have shown that ocular hemodynamics and eye tissue biomechanical properties play an important role in the pathophysiology of glaucoma. Nevertheless, better, non-invasive methods to assess these characteristics in vivo are essential for a thorough understanding of degenerative mechanisms. Here, we propose to measure ocular tissue movements induced by cardiac pulsations and study the ocular pulse waveform as an indicator of tissue compliance. Using a novel, low-cost and non-invasive device based on spectral-domain low coherence interferometry (SD-LCI, we demonstrate the potential of this technique to differentiate ocular hemodynamic and biomechanical properties. We measured the axial movement of the retina driven by the pulsatile ocular blood flow in 11 young healthy individuals, 12 older healthy individuals and 15 older treated glaucoma patients using our custom-made SD-OCT apparatus. The cardiac pulse was simultaneously measured through the use of an oximeter to allow comparison. Spectral components up to the second harmonic were obtained and analyzed. For the different cohorts, we computed a few parameters that characterize the three groups of individuals by analyzing the movement of the retinal tissue at two locations, using this simple, low-cost interferometric device. Our pilot study indicates that spectral analysis of the fundus pulsation has potential for the study of ocular biomechanical and vascular properties, as well as for the study of ocular disease.

  17. Comparison between pulsatile GnRH therapy and gonadotropins for ovulation induction in women with both functional hypothalamic amenorrhea and polycystic ovarian morphology.

    Science.gov (United States)

    Dumont, Agathe; Dewailly, Didier; Plouvier, Pauline; Catteau-Jonard, Sophie; Robin, Geoffroy

    2016-12-01

    Ovulation induction in patients having both functional hypothalamic amenorrhea (FHA) and polycystic ovarian morphology (PCOM) has been less studied in the literature. As results remain contradictory, no recommendations have yet been established. To compare pulsatile GnRH therapy versus gonadotropins for ovulation induction in "FHA-PCOM" patients and to determine if one treatment strikes as superior to the other. A 12-year retrospective study, comparing 55 "FHA-PCOM" patients, treated either with GnRH therapy (38 patients, 93 cycles) or with gonadotropins (17 patients, 53 cycles). Both groups were similar, defined by low serum LH and E2 levels, low BMI, excessive follicle number per ovary and/or high serum AMH level. Ovulation rates were significantly lower with gonadotropins (56.6% versus 78.6%, p = 0.005), with more cancellation and ovarian hyper-responses (14% versus 34% per initiated cycle, p < 0.005). Pregnancy rates were significantly higher with GnRH therapy, whether per initiated cycle (26.9% versus 7.6%, p = 0.005) or per patient (65.8% versus 23.5%, p = 0.007). In our study, GnRH therapy was more successful and safer than gonadotropins, for ovulation induction in "FHA-PCOM" patients. If results were confirmed by prospective studies, it could become a first-line treatment for this population, just as it is for FHA women without PCOM.

  18. Central Pulsatile Pressure and Flow Relationship in the Time and Frequency Domain to Characterise Hydraulic Input to the Brain and Cerebral Vascular Impedance.

    Science.gov (United States)

    Kim, Mi Ok; O'Rourke, Michael F; Adji, Audrey; Avolio, Alberto P

    2016-01-01

    In the time domain, pulsatile flow and pressure can be characterised as the ratio of the late systolic boost of flow or pressure to the pulse amplitude so as to estimate the hydraulic input to the brain. While vascular impedance has been widely used to represent the load presented to the heart by the systemic circulation, it has not been applied to the cerebral circulation.We set out to study the relationship between the pressure and the flow augmentation index (AIx) in the time domain and to determine cerebral vascular impedance using aortic blood pressure and cerebral blood flow waveforms in the frequency domain. Twenty-four young subjects (aged 21-39 years) were recruited; aortic pressure was derived using SphygmoCor from radial pressure. Flow waveforms were recorded from the middle cerebral artery. In three subjects, we performed the Valsalva manoeuvre to investigate their response to physiological intervention. There was a linear relationship between flow and pressure AIx, and cerebral impedance values were similar to those estimated for low resistance vascular beds. Substantial change in pressure and flow wave contour was observed during the Valsalva manoeuvre; however, the relationship in both the time and the frequency domains were unchanged. This confirms that aortic pressure and cerebral flow waveform can be used to study cerebral impedance.

  19. The dopamine beta-hydroxylase inhibitor nepicastat increases dopamine release and potentiates psychostimulant-induced dopamine release in the prefrontal cortex.

    Science.gov (United States)

    Devoto, Paola; Flore, Giovanna; Saba, Pierluigi; Bini, Valentina; Gessa, Gian Luigi

    2014-07-01

    The dopamine-beta-hydroxylase inhibitor nepicastat has been shown to reproduce disulfiram ability to suppress the reinstatement of cocaine seeking after extinction in rats. To clarify its mechanism of action, we examined the effect of nepicastat, given alone or in association with cocaine or amphetamine, on catecholamine release in the medial prefrontal cortex and the nucleus accumbens, two key regions involved in the reinforcing and motivational effects of cocaine and in the reinstatement of cocaine seeking. Nepicastat effect on catecholamines was evaluated by microdialysis in freely moving rats. Nepicastat reduced noradrenaline release both in the medial prefrontal cortex and in the nucleus accumbens, and increased dopamine release in the medial prefrontal cortex but not in the nucleus accumbens. Moreover, nepicastat markedly potentiated cocaine- and amphetamine-induced extracellular dopamine accumulation in the medial prefrontal cortex but not in the nucleus accumbens. Extracellular dopamine accumulation produced by nepicastat alone or by its combination with cocaine or amphetamine was suppressed by the α2 -adrenoceptor agonist clonidine. It is suggested that nepicastat, by suppressing noradrenaline synthesis and release, eliminated the α2 -adrenoceptor mediated inhibitory mechanism that constrains dopamine release and cocaine- and amphetamine-induced dopamine release from noradrenaline or dopamine terminals in the medial prefrontal cortex. © 2012 The Authors, Addiction Biology © 2012 Society for the Study of Addiction.

  20. Fatal attraction? Intraguild facilitation and suppression among predators

    Science.gov (United States)

    Sivy, Kelly J.; Pozzanghera, Casey B.; Grace, James B.; Prugh, Laura R.

    2017-01-01

    Competition and suppression are recognized as dominant forces that structure predator communities. Facilitation via carrion provisioning, however, is a ubiquitous interaction among predators that could offset the strength of suppression. Understanding the relative importance of these positive and negative interactions is necessary to anticipate community-wide responses to apex predator declines and recoveries worldwide. Using state-sponsored wolf (Canis lupus) control in Alaska as a quasi experiment, we conducted snow track surveys of apex, meso-, and small predators to test for evidence of carnivore cascades (e.g., mesopredator release). We analyzed survey data using an integrative occupancy and structural equation modeling framework to quantify the strengths of hypothesized interaction pathways, and we evaluated fine-scale spatiotemporal responses of nonapex predators to wolf activity clusters identified from radio-collar data. Contrary to the carnivore cascade hypothesis, both meso- and small predator occupancy patterns indicated guild-wide, negative responses of nonapex predators to wolf abundance variations at the landscape scale. At the local scale, however, we observed a near guild-wide, positive response of nonapex predators to localized wolf activity. Local-scale association with apex predators due to scavenging could lead to landscape patterns of mesopredator suppression, suggesting a key link between occupancy patterns and the structure of predator communities at different spatial scales.

  1. Fatal Attraction? Intraguild Facilitation and Suppression among Predators.

    Science.gov (United States)

    Sivy, Kelly J; Pozzanghera, Casey B; Grace, James B; Prugh, Laura R

    2017-11-01

    Competition and suppression are recognized as dominant forces that structure predator communities. Facilitation via carrion provisioning, however, is a ubiquitous interaction among predators that could offset the strength of suppression. Understanding the relative importance of these positive and negative interactions is necessary to anticipate community-wide responses to apex predator declines and recoveries worldwide. Using state-sponsored wolf (Canis lupus) control in Alaska as a quasi experiment, we conducted snow track surveys of apex, meso-, and small predators to test for evidence of carnivore cascades (e.g., mesopredator release). We analyzed survey data using an integrative occupancy and structural equation modeling framework to quantify the strengths of hypothesized interaction pathways, and we evaluated fine-scale spatiotemporal responses of nonapex predators to wolf activity clusters identified from radio-collar data. Contrary to the carnivore cascade hypothesis, both meso- and small predator occupancy patterns indicated guild-wide, negative responses of nonapex predators to wolf abundance variations at the landscape scale. At the local scale, however, we observed a near guild-wide, positive response of nonapex predators to localized wolf activity. Local-scale association with apex predators due to scavenging could lead to landscape patterns of mesopredator suppression, suggesting a key link between occupancy patterns and the structure of predator communities at different spatial scales.

  2. Biological control of olive fruit fly in California - release, establishment and impact of Psyttalia lounsburyi and Psyttalia humilis

    Science.gov (United States)

    Geographic strains of the African endoparasitoids Psyttalia lounsburyi and Psyttalia humilis (Hymenoptera: Braconidae) were released to suppress the olive fruit fly, Bactrocera oleae, in California from 2006 – 2016. Both parasitoid species were recovered post-release within the same fruit season; ho...

  3. Pressure suppression pool thermal mixing

    International Nuclear Information System (INIS)

    Cook, D.H.

    1984-01-01

    A model is developed and verified to describe the thermal mixing that occurs in the pressure suppression pool (PSP) of a commercial BWR. The model is designed specifically for a Mark-I containment and is intended for use in severe accident sequence analyses. The model produces space and time dependent temperature results throughout the PSP and is useful for evaluating the bulk PSP thermal mixing, the condensation effectiveness of the PSP, and the long-term containment integrity. The model is designed to accommodate single or multiple discharging T-quenchers, a PSP circumferential circulation induced by the residual heat removal system discharge, and the thermal stratification of the pool that occurs immediately after the relief valves close. The PSP thermal mixing model is verified by comparing the model predicted temperatures to experimental temperatures that were measured in an operating BWR suppression pool. The model is then used to investigate several PSP thermal mixing problems that include the time to saturate at full relief valve flow, the temperature response to a typical stuck open relief valve scenario, and the effect of operator rotation of the relief valve discharge point

  4. SU-F-19A-08: Optimal Time Release Schedule of In-Situ Drug Release During Permanent Prostate Brachytherapy

    International Nuclear Information System (INIS)

    Cormack, R; Ngwa, W; Makrigiorgos, G; Tangutoori, S; Rajiv, K; Sridhar, S

    2014-01-01

    Purpose: Permanent prostate brachytherapy spacers can be used to deliver sustained doses of radiosentitizing drug directly to the target, in order to enhance the radiation effect. Implantable nanoplatforms for chemo-radiation therapy (INCeRTs) have a maximum drug capacity and can be engineered to control the drug release schedule. The optimal schedule for sensitization during continuous low dose rate irradiation is unknown. This work studies the optimal release schedule of drug for both traditional sensitizers, and those that work by suppressing DNA repair processes. Methods: Six brachytherapy treatment plans were used to model the anatomy, implant geometry and calculate the spatial distribution of radiation dose and drug concentrations for a range of drug diffusion parameters. Three state partial differential equations (cells healthy, damaged or dead) modeled the effect of continuous radiation (radiosensitivities α,β) and cellular repair (time tr) on a cell population. Radiosensitization was modeled as concentration dependent change in α,β or tr which with variable duration under the constraint of fixed total drug release. Average cell kill was used to measure effectiveness. Sensitization by means of both enhanced damage and reduced repair were studied. Results: Optimal release duration is dependent on the concentration of radiosensitizer compared to the saturation concentration (csat) above which additional sensitization does not occur. Long duration drug release when enhancing α or β maximizes cell death when drug concentrations are generally over csat. Short term release is optimal for concentrations below saturation. Sensitization by suppressing repair has a similar though less distinct trend that is more affected by the radiation dose distribution. Conclusion: Models of sustained local radiosensitization show potential to increase the effectiveness of radiation in permanent prostate brachytherapy. INCeRTs with high drug capacity produce the greatest

  5. Riola release report

    Energy Technology Data Exchange (ETDEWEB)

    Woodward, E.C.

    1983-08-04

    Eleven hours after execution of the Riola Event (at 0826 PDT on 25 September 1980) in hole U2eq of the Nevada Test Site (NTS), a release of radioactivity began. When the seepage stopped at about noon the following day, up to some 3200 Ci of activity had been dispersed by light variable winds. On 26 September, examination of the geophone records showed six hours of low-level, but fairly continuous, activity before the release. Electrical measurements indicated that most cables were still intact to a depth below the stemming platform. A survey of the ground zero area showed that the seepage came through cracks between the surface conductor and the pad, through cracks in the pad, and through a crack adjacent to the pad around the mousehole (a small hole adjacent to the emplacement hole). To preclude undue radiation exposure or injury from a surprise subsidence, safety measures were instituted. Tritium seepage was suffucient to postpone site activities until a box and pipeline were emplaced to contain and remove the gas. Radiation release modeling and calculations were generally consistent with observations. Plug-hole interaction calculations showed that the alluvium near the bottom of the plug may have been overstressed and that improvements in the design of the plug-medium interface can be made. Experimental studies verified that the surface appearance of the plug core was caused by erosion, but, assuming a normal strength for the plug material, that erosion alone could not account for the disappearance of such a large portion of the stemming platform. Samples from downhole plug experiments show that the plug may have been considerably weaker than had been indicted by quality assurance (QA) samples. 19 references, 32 figures, 10 tables.

  6. Riola release report

    International Nuclear Information System (INIS)

    Woodward, E.C.

    1983-01-01

    Eleven hours after execution of the Riola Event (at 0826 PDT on 25 September 1980) in hole U2eq of the Nevada Test Site (NTS), a release of radioactivity began. When the seepage stopped at about noon the following day, up to some 3200 Ci of activity had been dispersed by light variable winds. On 26 September, examination of the geophone records showed six hours of low-level, but fairly continuous, activity before the release. Electrical measurements indicated that most cables were still intact to a depth below the stemming platform. A survey of the ground zero area showed that the seepage came through cracks between the surface conductor and the pad, through cracks in the pad, and through a crack adjacent to the pad around the mousehole (a small hole adjacent to the emplacement hole). To preclude undue radiation exposure or injury from a surprise subsidence, safety measures were instituted. Tritium seepage was suffucient to postpone site activities until a box and pipeline were emplaced to contain and remove the gas. Radiation release modeling and calculations were generally consistent with observations. Plug-hole interaction calculations showed that the alluvium near the bottom of the plug may have been overstressed and that improvements in the design of the plug-medium interface can be made. Experimental studies verified that the surface appearance of the plug core was caused by erosion, but, assuming a normal strength for the plug material, that erosion alone could not account for the disappearance of such a large portion of the stemming platform. Samples from downhole plug experiments show that the plug may have been considerably weaker than had been indicted by quality assurance (QA) samples. 19 references, 32 figures, 10 tables

  7. Allegheny County Toxics Release Inventory

    Data.gov (United States)

    Allegheny County / City of Pittsburgh / Western PA Regional Data Center — The Toxics Release Inventory (TRI) data provides information about toxic substances released into the environment or managed through recycling, energy recovery, and...

  8. The role of suppression in amblyopia.

    Science.gov (United States)

    Li, Jingrong; Thompson, Benjamin; Lam, Carly S Y; Deng, Daming; Chan, Lily Y L; Maehara, Goro; Woo, George C; Yu, Minbin; Hess, Robert F

    2011-06-13

    This study had three main goals: to assess the degree of suppression in patients with strabismic, anisometropic, and mixed amblyopia; to establish the relationship between suppression and the degree of amblyopia; and to compare the degree of suppression across the clinical subgroups within the sample. Using both standard measures of suppression (Bagolini lenses and neutral density [ND] filters, Worth 4-Dot test) and a new approach involving the measurement of dichoptic motion thresholds under conditions of variable interocular contrast, the degree of suppression in 43 amblyopic patients with strabismus, anisometropia, or a combination of both was quantified. There was good agreement between the quantitative measures of suppression made with the new dichoptic motion threshold technique and measurements made with standard clinical techniques (Bagolini lenses and ND filters, Worth 4-Dot test). The degree of suppression was found to correlate directly with the degree of amblyopia within our clinical sample, whereby stronger suppression was associated with a greater difference in interocular acuity and poorer stereoacuity. Suppression was not related to the type or angle of strabismus when this was present or the previous treatment history. These results suggest that suppression may have a primary role in the amblyopia syndrome and therefore have implications for the treatment of amblyopia.

  9. Caffeine-Induced Suppression of GABAergic Inhibition and Calcium-Independent Metaplasticity

    Directory of Open Access Journals (Sweden)

    Masako Isokawa

    2016-01-01

    Full Text Available GABAergic inhibition plays a critical role in the regulation of neuron excitability; thus, it is subject to modulations by many factors. Recent evidence suggests the elevation of intracellular calcium ([Ca2+]i and calcium-dependent signaling molecules underlie the modulations. Caffeine induces a release of calcium from intracellular stores. We tested whether caffeine modulated GABAergic transmission by increasing [Ca2+]i. A brief local puff-application of caffeine to hippocampal CA1 pyramidal cells transiently suppressed GABAergic inhibitory postsynaptic currents (IPSCs by 73.2 ± 6.98%. Time course of suppression and the subsequent recovery of IPSCs resembled DSI (depolarization-induced suppression of inhibition, mediated by endogenous cannabinoids that require a [Ca2+]i rise. However, unlike DSI, caffeine-induced suppression of IPSCs (CSI persisted in the absence of a [Ca2+]i rise. Intracellular applications of BAPTA and ryanodine (which blocks caffeine-induced calcium release from intracellular stores failed to prevent the generation of CSI. Surprisingly, ruthenium red, an inhibitor of multiple calcium permeable/release channels including those of stores, induced metaplasticity by amplifying the magnitude of CSI independently of calcium. This metaplasticity was accompanied with the generation of a large inward current. Although ionic basis of this inward current is undetermined, the present result demonstrates that caffeine has a robust Ca2+-independent inhibitory action on GABAergic inhibition and causes metaplasticity by opening plasma membrane channels.

  10. Agmatine suppresses peripheral sympathetic tone by inhibiting N-type Ca(2+) channel activity via imidazoline I2 receptor activation.

    Science.gov (United States)

    Kim, Young-Hwan; Jeong, Ji-Hyun; Ahn, Duck-Sun; Chung, Seungsoo

    2016-08-26

    Agmatine, a putative endogenous ligand of imidazoline receptors, suppresses cardiovascular function by inhibiting peripheral sympathetic tone. However, the molecular identity of imidazoline receptor subtypes and its cellular mechanism underlying the agmatine-induced sympathetic suppression remains unknown. Meanwhile, N-type Ca(2+) channels are important for the regulation of NA release in the peripheral sympathetic nervous system. Therefore, it is possible that agmatine suppresses NA release in peripheral sympathetic nerve terminals by inhibiting Ca(2+) influx through N-type Ca(2+) channels. We tested this hypothesis by investigating agmatine effect on electrical field stimulation (EFS)-evoked contraction and NA release in endothelium-denuded rat superior mesenteric arterial strips. We also investigated the effect of agmatine on the N-type Ca(2+) current in superior cervical ganglion (SCG) neurons in rats. Our study demonstrates that agmatine suppresses peripheral sympathetic outflow via the imidazoline I2 receptor in rat mesenteric arteries. In addition, the agmatine-induced suppression of peripheral vascular sympathetic tone is mediated by modulating voltage-dependent N-type Ca(2+) channels in sympathetic nerve terminals. These results suggest a potential cellular mechanism for the agmatine-induced suppression of peripheral sympathetic tone. Furthermore, they provide basic and theoretical information regarding the development of new agents to treat hypertension. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Metabolic control of vesicular glutamate transport and release.

    Science.gov (United States)

    Juge, Narinobu; Gray, John A; Omote, Hiroshi; Miyaji, Takaaki; Inoue, Tsuyoshi; Hara, Chiaki; Uneyama, Hisayuki; Edwards, Robert H; Nicoll, Roger A; Moriyama, Yoshinori

    2010-10-06

    Fasting has been used to control epilepsy since antiquity, but the mechanism of coupling between metabolic state and excitatory neurotransmission remains unknown. Previous work has shown that the vesicular glutamate transporters (VGLUTs) required for exocytotic release of glutamate undergo an unusual form of regulation by Cl(-). Using functional reconstitution of the purified VGLUTs into proteoliposomes, we now show that Cl(-) acts as an allosteric activator, and the ketone bodies that increase with fasting inhibit glutamate release by competing with Cl(-) at the site of allosteric regulation. Consistent with these observations, acetoacetate reduced quantal size at hippocampal synapses and suppresses glutamate release and seizures evoked with 4-aminopyridine in the brain. The results indicate an unsuspected link between metabolic state and excitatory neurotransmission through anion-dependent regulation of VGLUT activity. Copyright © 2010 Elsevier Inc. All rights reserved.

  12. Safety system for pressure suppression

    International Nuclear Information System (INIS)

    Wood, L.E.; Ludwig, G.J.; Tulsa, O.

    1975-01-01

    The rupture disk with rated breaking points is constrained by two supporting elements and has a convex-concave shape. For pressure suppression, it is reversable inversely to its bulging. Its surface has notches which are the rated breaking points and respond to higher pressures. The centre of the rupture disk contains an area of relatively smaller thickness that will burst at lower pressure and thus makes it applicable for lower pressures. For the response of the rupture disk centre, a thrust ring with a central opening may also be used. Its edge is formed into a convex-concave section supported on the edge of the rupture disk on the exit side. The free centre of the rupture disk is then the area of relative weakness. (RW/AK) [de

  13. Cold urticaria: inhibition of cold-induced histamine release by doxantrazole.

    Science.gov (United States)

    Bentley-Phillips, C B; Eady, R A; Greaves, M W

    1978-10-01

    Thirteen patients with cold urticaria were studied to assess the effect of the systemic drug doxantrazole, which has actions resembling disodium cromoglycate, on cold evoked histamine release. The patients, all of whom developed an immediate local whealing response after cooling of the forearm, demonstrated release of histamine into venous blood draining that forearm. Following doxantrazole treatment, significant suppression of histamine release occurred. In some but not all patients this was accompanied by diminution of urtication in response to cooling. A double-blind study was carried out in 3 subjects, all of whom showed diminished cold-stimulated histamine release after doxantrazole. Two of these showed clinical improvement. Doxantrazole had no effect on erythema due to intradermal histamine, but did suppress the erythematous reaction to intradermal injection of compound 48/80. Our results suggest that doxantrazole or related anti-allergic agents might be useful in the treatment of cold urticaria.

  14. Cold urticaria. Dissociation of cold-evoked histamine release and urticara following cold challenge.

    Science.gov (United States)

    Keahey, T M; Greaves, M W

    1980-02-01

    Nine patients with acquired cold urticaria were studied to assess the effects of beta-adrenergic agents, xanthines, and corticosteroids on cold-evoked histamine release from skin in vivo. The patients, in all of whom an immediate urticarial response developed after cooling of the forearm, demonstrated release of histamine into the venous blood draining that forearm. Following treatment with aminophylline and albuterol in combination or prednisone alone, suppression of histamine release occurred in all but one patient. In some patients, this was accompanied by a subjective diminution in pruritus or buring, but there was no significant improvement in the ensuing edema or erythema. In one patient, total suppression of histamine release was achieved without any effect on whealing and erythema in response to cold challenge. Our results suggest that histamine is not central to the pathogenesis of vascular changes in acquired cold urticaria.

  15. MEK5 suppresses osteoblastic differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Kaneshiro, Shoichi [Department of Orthopaedic Surgery, Japan Community Health Care Organization Osaka Hospital, 4-2-78 Fukushima, Fukushima Ward, Osaka City, Osaka 553-0003 (Japan); Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Otsuki, Dai; Yoshida, Kiyoshi; Yoshikawa, Hideki [Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan); Higuchi, Chikahisa, E-mail: c-higuchi@umin.ac.jp [Department of Orthopaedic Surgery, Graduate School of Medicine, Osaka University, 2-2 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2015-07-31

    Extracellular signal-regulated kinase 5 (ERK5) is a member of the mitogen-activated protein kinase (MAPK) family and is activated by its upstream kinase, MAPK kinase 5 (MEK5), which is a member of the MEK family. Although the role of MEK5 has been investigated in several fields, little is known about its role in osteoblastic differentiation. In this study, we have demonstrated the role of MEK5 in osteoblastic differentiation in mouse preosteoblastic MC3T3-E1 cells and bone marrow stromal ST2 cells. We found that treatment with BIX02189, an inhibitor of MEK5, increased alkaline phosphatase (ALP) activity and the gene expression of ALP, osteocalcin (OCN) and osterix, as well as it enhanced the calcification of the extracellular matrix. Moreover, osteoblastic cell proliferation decreased at a concentration of greater than 0.5 μM. In addition, knockdown of MEK5 using siRNA induced an increase in ALP activity and in the gene expression of ALP, OCN, and osterix. In contrast, overexpression of wild-type MEK5 decreased ALP activity and attenuated osteoblastic differentiation markers including ALP, OCN and osterix, but promoted cell proliferation. In summary, our results indicated that MEK5 suppressed the osteoblastic differentiation, but promoted osteoblastic cell proliferation. These results implied that MEK5 may play a pivotal role in cell signaling to modulate the differentiation and proliferation of osteoblasts. Thus, inhibition of MEK5 signaling in osteoblasts may be of potential use in the treatment of osteoporosis. - Highlights: • MEK5 inhibitor BIX02189 suppresses proliferation of osteoblasts. • MEK5 knockdown and MEK5 inhibitor promote differentiation of osteoblasts. • MEK5 overexpression inhibits differentiation of osteoblasts.

  16. Cobalt release from inexpensive jewellery

    DEFF Research Database (Denmark)

    Thyssen, Jacob Pontoppidan; Jellesen, Morten Stendahl; Menné, Torkil

    2010-01-01

    . Conclusions: This study showed that only a minority of inexpensive jewellery purchased in Denmark released cobalt when analysed with the cobalt spot test. As fashion trends fluctuate and we found cobalt release from dark appearing jewellery, cobalt release from consumer items should be monitored in the future......Objectives: The aim was to study 354 consumer items using the cobalt spot test. Cobalt release was assessed to obtain a risk estimate of cobalt allergy and dermatitis in consumers who would wear the jewellery. Methods: The cobalt spot test was used to assess cobalt release from all items...

  17. Charmonium formation and suppression in nuclear matter

    International Nuclear Information System (INIS)

    Xu Jiajun; Wang Jia; Zhuang Chao; Zhuang Pengfei

    2005-01-01

    The coupling Schroedinger equations describing the evolution of cc-bar states in nuclear matter are analytically and systematically solved via perturbation method, and the correlation between charmonium formation and nuclear absorption is investigated. After calculating J/Ψ and Ψ' suppression in nucleon-nucleus collisions and comparing with experiment data, it is found that the formation time effect plays an important rule in charmonium suppression, especially in Ψ' suppression. (authors)

  18. Poppers: more evidence of suppressed immunity.

    Science.gov (United States)

    James, J S

    1999-08-20

    Evidence from studies in mice shows that exposure to isobutyl nitrite suppresses the immune system. This immune suppression allows for bacterial growth in the lungs and livers of infected mice and can inhibit the ability of mediastinal lymph nodes to respond to antigen-specific stimulation. The mechanism for immune suppression may be a reduction in CD4+ and CD8+ T cell populations in the mediastinal lymph nodes following pulmonary infection with Listeria monocytogenes.

  19. Components of Streptococcus pneumoniae suppress allergic airways disease and NKT cells by inducing regulatory T cells.

    Science.gov (United States)

    Thorburn, Alison N; Foster, Paul S; Gibson, Peter G; Hansbro, Philip M

    2012-05-01

    Asthma is an allergic airways disease (AAD) caused by dysregulated immune responses and characterized by eosinophilic inflammation, mucus hypersecretion, and airway hyperresponsiveness (AHR). NKT cells have been shown to contribute to AHR in some mouse models. Conversely, regulatory T cells (Tregs) control aberrant immune responses and maintain homeostasis. Recent evidence suggests that Streptococcus pneumoniae induces Tregs that have potential to be harnessed therapeutically for asthma. In this study, mouse models of AAD were used to identify the S. pneumoniae components that have suppressive properties, and the mechanisms underlying suppression were investigated. We tested the suppressive capacity of type-3-polysaccharide (T3P), isolated cell walls, pneumolysoid (Ply) and CpG. When coadministered, T3P + Ply suppressed the development of: eosinophilic inflammation, Th2 cytokine release, mucus hypersecretion, and AHR. Importantly, T3P + Ply also attenuated features of AAD when administered during established disease. We show that NKT cells contributed to the development of AAD and also were suppressed by T3P + Ply treatment. Furthermore, adoptive transfer of NKT cells induced AHR, which also could be reversed by T3P + Ply. T3P + Ply-induced Tregs were essential for the suppression of NKT cells and AAD, which was demonstrated by Treg depletion. Collectively, our results show that the S. pneumoniae components T3P + Ply suppress AAD through the induction of Tregs that blocked the activity of NKT cells. These data suggest that S. pneumoniae components may have potential as a therapeutic strategy for the suppression of allergic asthma through the induction of Tregs and suppression of NKT cells.

  20. Platelet activating factor receptor binding plays a critical role in jet fuel-induced immune suppression

    International Nuclear Information System (INIS)

    Ramos, Gerardo; Kazimi, Nasser; Nghiem, Dat X.; Walterscheid, Jeffrey P.; Ullrich, Stephen E.

    2004-01-01

    Applying military jet fuel (JP-8) or commercial jet fuel (Jet-A) to the skin of mice suppresses the immune response in a dose-dependant manner. The release of biological response modifiers, particularly prostaglandin E 2 (PGE 2 ), is a critical step in activating immune suppression. Previous studies have shown that injecting selective cyclooxygenase-2 inhibitors into jet fuel-treated mice blocks immune suppression. Because the inflammatory phospholipid mediator, platelet-activating factor (PAF), up-regulates cyclooxygenase-2 production and PGE 2 synthesis by keratinocytes, we tested the hypothesis that PAF-receptor binding plays a role in jet fuel-induced immune suppression. Treating keratinocyte cultures with PAF and/or jet fuel (JP-8 and Jet-A) stimulates PGE 2 secretion. Jet fuel-induced PGE 2 production was suppressed by treating the keratinocytes with specific PAF-receptor antagonists. Injecting mice with PAF, or treating the skin of the mice with JP-8, or Jet-A, induced immune suppression. Jet fuel-induced immune suppression was blocked when the jet fuel-treated mice were injected with PAF-receptor antagonists before treatment. Jet fuel treatment has been reported to activate oxidative stress and treating the mice with anti-oxidants (Vitamins C, or E or beta-hydroxy toluene), before jet fuel application, interfered with immune suppression. These findings confirm previous studies showing that PAF-receptor binding can modulate immune function. Furthermore, they suggest that PAF-receptor binding may be an early event in the induction of immune suppression by immunotoxic environmental agents that target the skin

  1. Deconstructing Interocular Suppression: Attention and Divisive Normalization.

    Directory of Open Access Journals (Sweden)

    Hsin-Hung Li

    2015-10-01

    Full Text Available In interocular suppression, a suprathreshold monocular target can be rendered invisible by a salient competitor stimulus presented in the other eye. Despite decades of research on interocular suppression and related phenomena (e.g., binocular rivalry, flash suppression, continuous flash suppression, the neural processing underlying interocular suppression is still unknown. We developed and tested a computational model of interocular suppression. The model included two processes that contributed to the strength of interocular suppression: divisive normalization and attentional modulation. According to the model, the salient competitor induced a stimulus-driven attentional modulation selective for the location and orientation of the competitor, thereby increasing the gain of neural responses to the competitor and reducing the gain of neural responses to the target. Additional suppression was induced by divisive normalization in the model, similar to other forms of visual masking. To test the model, we conducted psychophysics experiments in which both the size and the eye-of-origin of the competitor were manipulated. For small and medium competitors, behavioral performance was consonant with a change in the response gain of neurons that responded to the target. But large competitors induced a contrast-gain change, even when the competitor was split between the two eyes. The model correctly predicted these results and outperformed an alternative model in which the attentional modulation was eye specific. We conclude that both stimulus-driven attention (selective for location and feature and divisive normalization contribute to interocular suppression.

  2. Deconstructing Interocular Suppression: Attention and Divisive Normalization.

    Science.gov (United States)

    Li, Hsin-Hung; Carrasco, Marisa; Heeger, David J

    2015-10-01

    In interocular suppression, a suprathreshold monocular target can be rendered invisible by a salient competitor stimulus presented in the other eye. Despite decades of research on interocular suppression and related phenomena (e.g., binocular rivalry, flash suppression, continuous flash suppression), the neural processing underlying interocular suppression is still unknown. We developed and tested a computational model of interocular suppression. The model included two processes that contributed to the strength of interocular suppression: divisive normalization and attentional modulation. According to the model, the salient competitor induced a stimulus-driven attentional modulation selective for the location and orientation of the competitor, thereby increasing the gain of neural responses to the competitor and reducing the gain of neural responses to the target. Additional suppression was induced by divisive normalization in the model, similar to other forms of visual masking. To test the model, we conducted psychophysics experiments in which both the size and the eye-of-origin of the competitor were manipulated. For small and medium competitors, behavioral performance was consonant with a change in the response gain of neurons that responded to the target. But large competitors induced a contrast-gain change, even when the competitor was split between the two eyes. The model correctly predicted these results and outperformed an alternative model in which the attentional modulation was eye specific. We conclude that both stimulus-driven attention (selective for location and feature) and divisive normalization contribute to interocular suppression.

  3. Numerical modelling on pulsatile flow of Casson nanofluid through an inclined artery with stenosis and tapering under the influence of magnetic field and periodic body acceleration

    Science.gov (United States)

    Ponalagusamy, R.; Priyadharshini, S.

    2017-11-01

    The present study investigates the pulsatile flow of Casson nanofluid through an inclined and stenosed artery with tapering in the presence of magnetic field and periodic body acceleration. The iron oxide nanoparticles are allowed to flow along with it. The governing equations for the flow of Casson fluid when the artery is tapered slightly having mild stenosis are highly non-linear and the momentum equations for temperature and concentration are coupled and are solved using finite difference numerical schemes in order to find the solutions for velocity, temperature, concentration, wall shear stress, and resistance to blood flow. The aim of the present study is to analyze the effects of flow parameters on the flow of nanofluid through an inclined arterial stenosis with tapering. These effects are represented graphically and concluded that the wall shear stress profiles enhance with increase in yield stress, magnetic field, thermophoresis parameter and decreases with Brownian motion parameter, local temperature Grashof number, local nanoparticle Grashof number. The significance of the model is the existence of yield stress and it is examined that when the rheology of blood changes from Newtonian to Casson fluid, the percentage of decrease in the flow resistance is higher with respect to the increase in the parameters local temperature Grashof number, local nanoparticle Grashof number, Brownian motion parameter, and Prandtl number. It is pertinent to observe that increase in the Brownian motion parameter leads to increment in concentration and temperature profiles. It is observed that the concentration of nanoparticles decreases with increase in the value of thermophoresis parameter.

  4. [Revelation of a polymicrocystic ovary syndrome after one month's treatment by pulsatile GnRH in a patient presenting with functional hypothalamic amenorrhea].

    Science.gov (United States)

    Reyss, A C; Merlen, E; Demerle, C; Dewailly, D

    2003-12-01

    Polycystic ovary syndrome (PCOS) and hypothalamic amenorrhea (HA) are the most frequent causes of endocrine infertility, but their association is an uncommon occurrence. We report the case of a 28-year old woman suffering from infertility and amenorrhea. Her weight was normal (BMI = 19) and she had no hirsutism. She self-reported food restriction and a 10 kg weight loss 5 years ago, concomitant with the onset of amenorrhea. At the initial evaluation, the patient was considered as having HA due to food restriction. At ultrasonography, ovaries were small and multifollicular (right and left area: 2.2 and 2.5 cm(2), respectively; number of cysts 2-9 mm in diameter: 15 and 12, respectively), and no stromal hypertrophy was noted. She has been treated for 1 month by intravenous pulsatile GnRH administration. Although the doses were increased from 5 to 15 microg/pulse every 90 min, no E2 response and no follicular development were observed. Hormonal re-evaluation revealed normal levels of serum LH, FSH and androgens, and a normal LH/FSH ratio. However, a typical aspect of PCO was found at ultrasound (right and left area: 6.5 and 5.5 cm(2), respectively, and more than 15 small cysts arranged peripherally around an increased central stroma in each ovary). The treatment has been then switched to hMG, using the low dose step-up regimen and starting with 75 U/day. In the absence of response after 2 weeks, the dose was increased to 112.5 U/day and a multifollicular reaction occurred, leading to cancellation. In conclusion, we hypothesize that this patient had a "hidden" PCOS when she was hypogonadotrophic and that it developed very rapidly after restitution of a normal gonadotropin level under exogenous GnRH. This occurred despite a low insulin level, showing that hyperinsulinism is not a prerequisite for the development of PCOS in every case.

  5. Low-dose prospectively electrocardiogram-gated axial dual-source CT angiography in patients with pulsatile bilateral bidirectional Glenn Shunt: an alternative noninvasive method for postoperative morphological estimation.

    Directory of Open Access Journals (Sweden)

    Xiaopeng Ji

    Full Text Available To explore the clinical value of low-dose prospectively electrocardiogram-gated axial dual-source CT angiography (low-dose PGA scanning, CTA in patients with pulsatile bilateral bidirectional Glenn shunt (bBDG as an alternative noninvasive method for postoperative morphological estimation.Twenty patients with pulsatile bBDG (mean age 4.2±1.6 years underwent both low-dose PGA scanning and conventional cardiac angiography (CCA for the morphological changes. The morphological evaluation included the anatomy of superior vena cava (SVC and pulmonary artery (PA, the anastomotic location, thrombosis, aorto-pulmonary collateral circulation, pulmonary arteriovenous malformations, etc. Objective and subjective image quality was assessed. Bland-Altman analysis and linear regression analyses were used to evaluate the correlation on measurements between CTA and CCA. Effective radiation dose of both modalities was calculated.The CT attenuation value of bilateral SVC and PA was higher than 300 HU. The average subjective image quality score was 4.05±0.69. The morphology of bilateral SVC and PA was displayed completely and intuitively by CTA images. There were 24 SVC above PA and 15 SVC beside PA. Thrombosis was found in 1 patient. Collateral vessels were detected in 13 patients. No pulmonary arteriovenous malformation was found in our study. A strong correlation (R2>0.8, P0.The mean effective dose of CTA and CCA was 0.50±0.17 mSv and 4.85±1.34 mSv respectively.CT angiography with a low-dose PGA scanning is an accurate and reliable noninvasive examination in the assessment of morphological changes in patients with pulsatile bBDG.

  6. Boiling Suppression in Convective Flow

    International Nuclear Information System (INIS)

    Aounallah, Y.

    2004-01-01

    The development of convective boiling heat transfer correlations and analytical models has almost exclusively been based on measurements of the total heat flux, and therefore on the overall two-phase heat transfer coefficient, when the well-known heat transfer correlations have often assumed additive mechanisms, one for each mode of heat transfer, convection and boiling. While the global performance of such correlations can readily be assessed, the predictive capability of the individual components of the correlation has usually remained elusive. This becomes important when, for example, developing mechanistic models for subcooled void formation based on the partitioning of the wall heat flux into a boiling and a convective component, or when extending a correlation beyond its original range of applications where the preponderance of the heat transfer mechanisms involved can be significantly different. A new examination of existing experimental heat transfer data obtained under fixed hydrodynamic conditions, whereby the local flow conditions are decoupled from the local heat flux, has allowed the unequivocal isolation of the boiling contribution over a broad range of thermodynamic qualities (0 to 0.8) for water at 7 MPa. Boiling suppression, as the quality increases, has consequently been quantified, thus providing valuable new insights on the functionality and contribution of boiling in convective flows. (author)

  7. Release of Suppressed Red Spruce Using Canopy Gap Creation--Ecological Restoration in the Central Appalachians

    Science.gov (United States)

    J.S. Rentch; W.M. Ford; Thomas Schuler; Jeff Palmer; C.A. Diggins

    2016-01-01

    Red spruce (Picea rubens) and red spruce-northern hardwood mixed stands once covered as much as 300,000 ha in the Central Appalachians, but now comprise no more than 21,000 ha. Recently, interest in restoration of this forest type has increased because red spruce forests provide habitat for a number of rare animal species. Our study reports the...

  8. Released radioactivity reducing facility

    International Nuclear Information System (INIS)

    Tanaka, Takeaki.

    1992-01-01

    Upon occurrence of a reactor accident, penetration portions of a reactor container, as a main leakage source from a reactor container, are surrounded by a plurality of gas-tight chambers, the outside of which is surrounded by highly gas-tightly buildings. Branched pipelines of an emergency gas processing system are introduced to each of the gas-tight chambers and they are joined and in communication with an emergency gas processing device. With such a constitution, radioactive materials are prevented from leaking directly from the buildings. Further, pipeline openings of the emergency gas processing facility are disposed in the plurality highly gas-tight penetration chambers. If the radioactive materials are leaked from the reactor to elevate the pressure in the penetration chambers, the radioactive materials are introduced to a filter device in the emergency gas processing facility by way of the branched pipelines, filtered and then released to the atmosphere. Accordingly, the reliability and safety of the system can be improved. (T.M.)

  9. Containment and release management

    International Nuclear Information System (INIS)

    Lehner, J.R.; Pratt, W.T.

    1988-01-01

    Reducing the risk from potentially severe accidents by appropriate accident management strategies is receiving increased attention from the international reactor safety community. Considerable uncertainty still surrounds some of the physical phenomena likely to occur during a severe accident. The USNRC, in developing its research plan for accident management, wants to ensure that both the developers and implementers of accident management strategies are aware of the uncertainty associated with the plant operators' ability to correctly diagnose an accident, as well as the uncertainties associated with various preventive and mitigative strategies. The use of a particular accident management strategy can have both positive and negative effects on the status of a plant and these effects must be carefully weighed before a particular course of action is chosen and implemented. By using examples of severe accident scenarios, initial insights are presented here regarding the indications plant operators may have to alert them to particular accident states. Insights are also offered on the various management actions operators and plant technical staff might pursue for particular accident situations and the pros and cons associated with such actions. The examples given are taken for the most part from the containment and release phase of accident management, since this is the current focus of the effort in the accident management area at Brookhaven National Laboratory. 2 refs

  10. Released radioactivity reducing device

    International Nuclear Information System (INIS)

    Miyamoto, Yumi.

    1995-01-01

    A water scrubber is disposed in a scrubber tank and a stainless steel fiber filter is disposed above the water scrubber. The upper end of the scrubber tank is connected by way of a second bent tube to a capturing vessel incorporating a moisture removing layer and an activated carbon filter. The exit of the capturing vessel is connected to a stack. Upon occurrence of an accident of a BWR-type power plant, gases containing radioactive materials released from a reactor container are discharged into the water scrubber from a first bent tube through a venturi tube nozzle, and water soluble and aerosol-like radioactive materials are captured in the water. Aerosol and splashes of water droplets which can not be captured thoroughly by the water scrubber are captured by the stainless steel fiber filter. Gases passing through the scrubber tank are introduced to a capturing vessel through a second bent tube, and organic iodine is captured by the activated carbon filter. (I.N.)

  11. COMMERCIAL SNF ACCIDENT RELEASE FRACTIONS

    Energy Technology Data Exchange (ETDEWEB)

    S.O. Bader

    1999-10-18

    The purpose of this design analysis is to specify and document the total and respirable fractions for radioactive materials that are released from an accident event at the Monitored Geologic Repository (MGR) involving commercial spent nuclear fuel (CSNF) in a dry environment. The total and respirable release fractions will be used to support the preclosure licensing basis for the MGR. The total release fraction is defined as the fraction of total CSNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. The radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses. This subset of the total release fraction is referred to as the respirable release fraction. Potential accidents may involve waste forms that are characterized as either bare (unconfined) fuel assemblies or confined fuel assemblies. The confined CSNF assemblies at the MGR are contained in shipping casks, canisters, or disposal containers (waste packages). In contrast to the bare fuel assemblies, the container that confines the fuel assemblies has the potential of providing an additional barrier for diminishing the total release fraction should the fuel rod cladding breach during an accident. However, this analysis will not take credit for this additional bamer and will establish only the total release fractions for bare unconfined CSNF assemblies, which may however be

  12. COMMERCIAL SNF ACCIDENT RELEASE FRACTIONS

    International Nuclear Information System (INIS)

    S.O. Bader

    1999-01-01

    The purpose of this design analysis is to specify and document the total and respirable fractions for radioactive materials that are released from an accident event at the Monitored Geologic Repository (MGR) involving commercial spent nuclear fuel (CSNF) in a dry environment. The total and respirable release fractions will be used to support the preclosure licensing basis for the MGR. The total release fraction is defined as the fraction of total CSNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. The radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses. This subset of the total release fraction is referred to as the respirable release fraction. Potential accidents may involve waste forms that are characterized as either bare (unconfined) fuel assemblies or confined fuel assemblies. The confined CSNF assemblies at the MGR are contained in shipping casks, canisters, or disposal containers (waste packages). In contrast to the bare fuel assemblies, the container that confines the fuel assemblies has the potential of providing an additional barrier for diminishing the total release fraction should the fuel rod cladding breach during an accident. However, this analysis will not take credit for this additional bamer and will establish only the total release fractions for bare unconfined CSNF assemblies, which may however be

  13. Underground water stress release models

    Science.gov (United States)

    Li, Yong; Dang, Shenjun; Lü, Shaochuan

    2011-08-01

    The accumulation of tectonic stress may cause earthquakes at some epochs. However, in most cases, it leads to crustal deformations. Underground water level is a sensitive indication of the crustal deformations. We incorporate the information of the underground water level into the stress release models (SRM), and obtain the underground water stress release model (USRM). We apply USRM to the earthquakes occurred at Tangshan region. The analysis shows that the underground water stress release model outperforms both Poisson model and stress release model. Monte Carlo simulation shows that the simulated seismicity by USRM is very close to the real seismicity.

  14. Flash release an alternative for releasing complex MEMS devices

    NARCIS (Netherlands)

    Deladi, S.; Krijnen, Gijsbertus J.M.; Elwenspoek, Michael Curt

    2004-01-01

    A novel time-saving and cost-effective release technique has been developed and is described. The physical nature of the process is explained in combination with experimental observations. The results of the flash release process are compared with those of freeze-drying and supercritical CO2

  15. Anaphylatoxin C3a induced mediator release from mast cells

    International Nuclear Information System (INIS)

    Herrscher, R.; Hugli, T.E.; Sullivan, T.J.

    1986-01-01

    The authors investigated the biochemical and functional consequences of the binding of highly purified human C3a to isolated rat serosal mast cells. C3a caused a dose-dependent (1-30 μM), noncytotoxic release of up to 64% (+/- 7 SEM) of the mast cell histamine content. C3a (10μM) increased 45 Ca ++ uptake 8.2- fold (+/- 2.2 SEM) above unstimulated control values within 10 minutes. Arachidonyl-diacylglycerol and arachidonyl-monoacylglycerol levels increased significantly within 2 minutes after C3a (10 μM) stimulation. Turnover of phosphatidylinositol, phosphatidic acid, and phosphatidylcholine were increased within 15 minutes. In contrast to antigen, C3a stimulation (10 μM) was not enhanced by exogenous phosphatidylserine, and was not inhibited by ethanol (100 μmM). C3a suppressed arachidonic acid (AA) release to 38% (+/- 9 SEM) below baseline, and did not cause PGD 2 formation. C3a and the desarginine form of C3a caused identical responses in all experiments. These studies indicate that C3a stimulation activates mast cell preformed mediator release in a manner very similar to antigen-IgE stimulation, but C3a suppresses free AA levels and does not stimulate PGD 2 synthesis

  16. Mechanisms of inhibition of vasopressin release during moderate antiorthostatic posture change in humans

    DEFF Research Database (Denmark)

    Pump, B.; Gabrielsen, A.; Christensen, N.J.

    1999-01-01

    The hypothesis was tested that the carotid baroreceptor stimulation caused by a posture change from upright seated with legs horizontal (Seat) to supine (Sup) participates in the suppression of arginine vasopressin (AVP) release. Ten healthy males underwent this posture change for 30 min without...... decreased from 0.9 +/- 0.2 to 0.5 +/- 0.1 pg/ml (P posture...

  17. Evidence that shock-induced immune suppression is mediated by adrenal hormones and peripheral beta-adrenergic receptors.

    Science.gov (United States)

    Cunnick, J E; Lysle, D T; Kucinski, B J; Rabin, B S

    1990-07-01

    Our previous work has demonstrated that presentations of mild foot-shock to Lewis rats induces a suppression of splenic and peripheral blood lymphocyte responses to nonspecific T-cell mitogens. The present study demonstrated that adrenalectomy prevented the shock-induced suppression of the mitogenic response of peripheral blood T-cells but did not attenuate the suppression of splenic T-cells. Conversely, the beta-adrenergic receptor antagonists, propranolol and nadolol, attenuated the shock-induced suppression of splenic T-cells in a dose-dependent manner but did not attenuate suppression of the blood mitogen response. These data indicate that distinct mechanisms mediate the shock-induced suppression of T-cell responsiveness to mitogens in the spleen and the peripheral blood. The results indicate that the peripheral release of catecholamines is responsible for splenic immune suppression and that adrenal hormones, which do not interact with beta-adrenergic receptors, are responsible for shock-induced suppression of blood mitogenic responses.

  18. Burst suppression probability algorithms: state-space methods for tracking EEG burst suppression

    Science.gov (United States)

    Chemali, Jessica; Ching, ShiNung; Purdon, Patrick L.; Solt, Ken; Brown, Emery N.

    2013-10-01

    Objective. Burst suppression is an electroencephalogram pattern in which bursts of electrical activity alternate with an isoelectric state. This pattern is commonly seen in states of severely reduced brain activity such as profound general anesthesia, anoxic brain injuries, hypothermia and certain developmental disorders. Devising accurate, reliable ways to quantify burst suppression is an important clinical and research problem. Although thresholding and segmentation algorithms readily identify burst suppression periods, analysis algorithms require long intervals of data to characterize burst suppression at a given time and provide no framework for statistical inference. Approach. We introduce the concept of the burst suppression probability (BSP) to define the brain's instantaneous propensity of being in the suppressed state. To conduct dynamic analyses of burst suppression we propose a state-space model in which the observation process is a binomial model and the state equation is a Gaussian random walk. We estimate the model using an approximate expectation maximization algorithm and illustrate its application in the analysis of rodent burst suppression recordings under general anesthesia and a patient during induction of controlled hypothermia. Main result. The BSP algorithms track burst suppression on a second-to-second time scale, and make possible formal statistical comparisons of burst suppression at different times. Significance. The state-space approach suggests a principled and informative way to analyze burst suppression that can be used to monitor, and eventually to control, the brain states of patients in the operating room and in the intensive care unit.

  19. Simulation of Axial Combustion Instability Development and Suppression in Solid Rocket Motors

    Directory of Open Access Journals (Sweden)

    David R. Greatrix

    2009-03-01

    Full Text Available In the design of solid-propellant rocket motors, the ability to understand and predict the expected behaviour of a given motor under unsteady conditions is important. Research towards predicting, quantifying, and ultimately suppressing undesirable strong transient axial combustion instability symptoms necessitates a comprehensive numerical model for internal ballistic simulation under dynamic flow and combustion conditions. An updated numerical model incorporating recent developments in predicting negative and positive erosive burning, and transient, frequency-dependent combustion response, in conjunction with pressure-dependent and acceleration-dependent burning, is applied to the investigation of instability-related behaviour in a small cylindrical-grain motor. Pertinent key factors, like the initial pressure disturbance magnitude and the propellant's net surface heat release, are evaluated with respect to their influence on the production of instability symptoms. Two traditional suppression techniques, axial transitions in grain geometry and inert particle loading, are in turn evaluated with respect to suppressing these axial instability symptoms.

  20. Suppression Pools: paradigm of the thermalhydraulic effect on severe accidents

    International Nuclear Information System (INIS)

    Herranz, L. E.; Lopez del Pra, C.

    2016-01-01

    Influence of thermal-hydrualic phenomena on severe accident unforlding is beyond question. The present paper supports this statement on two key aspects of a severe accident: preservation of containment integrity and transport of fission products once released from fuel. To illustrate them, the attention is focused on suppression pools performance and, particularly, on some recent findings stemming from authors research of Fukushima scenarios. Gas behvaior at the injection point and its later evolution, potential axial and/or azimuthal stratification of the aqueous body or water saturation state, are some of the processes tha more strongly affect the role of pools as a mass and energy sink. They are described and discussed in detail. (Author)

  1. Psychopathology and Thought Suppression: A Quantitative Review

    Science.gov (United States)

    Magee, Joshua C.; Harden, K. Paige; Teachman, Bethany A.

    2012-01-01

    Recent theories of psychopathology have suggested that thought suppression intensifies the persistence of intrusive thoughts, and proposed that difficulty with thought suppression may differ between groups with and without psychopathology. The current meta-analytic review evaluates empirical evidence for difficulty with thought suppression as a function of the presence and specific type of psychopathology. Based on theoretical proposals from the psychopathology literature, diagnosed and analogue samples were expected to show greater recurrence of intrusive thoughts during thought suppression attempts than non-clinical samples. However, results showed no overall differences in the recurrence of thoughts due to thought suppression between groups with and without psychopathology. There was, nevertheless, variation in the recurrence of thoughts across different forms of psychopathology, including relatively less recurrence during thought suppression for samples with symptoms of Obsessive-Compulsive Disorder, compared to non-clinical samples. However, these differences were typically small and provided only mixed support for existing theories. Implications for cognitive theories of intrusive thoughts are discussed, including proposed mechanisms underlying thought suppression. PMID:22388007

  2. Vital Signs-HIV Care Saves Lives: Viral Suppression is Key

    Centers for Disease Control (CDC) Podcasts

    2014-11-25

    This podcast is based on the December 2014 CDC Vital Signs report. For people living with HIV, Viral suppression is critical. By getting tested and taking HIV medicines, individuals living with HIV can achieve very low levels of HIV in the body.  Created: 11/25/2014 by National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 11/25/2014.

  3. Tracks FAQs: What Are Suppressed Data And How Can It Be Used?

    Centers for Disease Control (CDC) Podcasts

    2011-03-09

    In this podcast, CDC Tracking experts address how you can get a better view of suppressed data. Do you have a question for our Tracking experts? Please e-mail questions to trackingsupport@cdc.gov.  Created: 3/9/2011 by National Center for Environmental Health, Division of Environmental Hazards and Health Effects, Environmental Health Tracking Branch.   Date Released: 3/9/2011.

  4. To treat or not to treat: puberty suppression in childhood-onset gender dysphoria

    OpenAIRE

    Costa, Rosalia; Carmichael, Polly; Colizzi, Marco

    2016-01-01

    Puberty suppression using gonadotropin-releasing-hormone analogues (GnRHa) has become increasingly accepted as an intervention during the early stages of puberty (Tanner stage 2-3) in individuals with clear signs of childhood-onset gender dysphoria. However, lowering the age threshold for using medical intervention for children with gender dysphoria is still a matter of contention, and is more controversial than treating the condition in adolescents and adults, as children with gender dysphor...

  5. Regional Extent of Peripheral Suppression in Amblyopia.

    Science.gov (United States)

    Babu, Raiju J; Clavagnier, Simon; Bobier, William R; Thompson, Benjamin; Hess, Robert F

    2017-04-01

    Previously, we have mapped amblyopic eye suppression within the central 20° of the visual field and observed a gradient of suppression that is strongest in central vision and weakens with increasing eccentricity. In this study, using a large dichoptic display, we extend our novel suppression mapping approach further into the periphery (from 20°-60°) to assess whether suppression continues to decline with eccentricity or plateaus. Sixteen participants with amblyopia (10 with strabismus, 6 with anisometropia without strabismus; mean age: 37.9 ± 11 years) and six normal observers (mean age: 28.3 ± 5 years) took part. The visual stimulus (60° diameter), viewed from 57 cm, was composed of four concentric annuli (5° radius) with alternate contrast polarities starting from an eccentricity of 10°. Each annulus was divided into eight sectors subtending 45° of visual angle. Participants adjusted the contrast of a single sector presented to the fellow eye to match the perceived contrast of the remaining stimulus elements that were presented to the amblyopic eye. A matching contrast that was lower in the fellow eye than the amblyopic eye indicated suppression. Patients with strabismus exhibited significantly stronger interocular suppression than controls across all eccentricities (P = 0.01). Patients with anisometropia did not differ from controls (P = 0.58). Suppression varied significantly with eccentricity (P = 0.005) but this effect did not differ between patient groups (P = 0.217). In amblyopia, suppression is present beyond the central 10° in patients with strabismus. Suppression becomes weaker at greater eccentricities and this may enable peripheral fusion that could be used by binocular treatment methods.

  6. Sustained release of radioprotective agents

    International Nuclear Information System (INIS)

    Shani, J.

    1980-11-01

    New pharmaceutical formulations for the sustained release into the G.I. tract of radioprotective agents have been developed by the authors. The experimental method initially consisted in the production of methylcellulose microcapsules. This method failed apparently because of the premature ''explosion'' of the microcapsules and the consequent premature release of massive amounts of the drug. A new method has been developed which consists in drying and pulverising cysteamine and cysteine preparations, mixing them in various proportions with stearic acid and ethylcellulose as carriers. The mixture is then compressed into cylindrical tablets at several pressure values and the leaching rate of the radioprotective agents is then measured by spectrophotometry. The relation between the concentration of the active drug and its rate of release, and the effect on the release rate of the pressure applied to the tablet during its formation were also investigated. Results indicating that the release rate was linearly related to the square root of ''t'' seem to be in agreement with what is predictable, according to Higuchi's equation, save for the very initial and terminal phases. A clear correlation was also established between the stearic acid/ethylcellulose ratios and the release of 20% cysteine, namely a marked decrease in the rate of cysteine release was observed with increasing concentrations of stearic acid. Finally, it was observed that a higher formation pressure results in quicker release of the drug

  7. Press Oil Final Release Survey

    Energy Technology Data Exchange (ETDEWEB)

    Whicker, Jeffrey Jay [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ruedig, Elizabeth [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-05-11

    There are forty-eight 55 gallon barrels filled with hydraulic oil that are candidates for release and recycle. This oil needs to be characterized prior to release. Principles of sampling as provided in MARSAME/MARSSIM approaches were used as guidance for sampling.

  8. Workload Control with Continuous Release

    NARCIS (Netherlands)

    Phan, B. S. Nguyen; Land, M. J.; Gaalman, G. J. C.

    2009-01-01

    Workload Control (WLC) is a production planning and control concept which is suitable for the needs of make-to-order job shops. Release decisions based on the workload norms form the core of the concept. This paper develops continuous time WLC release variants and investigates their due date

  9. Suppression of autoimmune retinal inflammation by an antiangiogenic drug.

    Directory of Open Access Journals (Sweden)

    Takeru Yoshimura

    Full Text Available Chronic and recurrent uveitis account for approximately 10% of legal blindness in the western world. Autoimmune uveitis is driven by activated CD4(+ T cells that differentiate into effector T helper cells (Th1, Th2, and Th17 which release proinflammatory cytokines that damage the retina. In this study we investigated the effect of the methionine aminopeptidase 2 (MetAP2 inhibitor, Lodamin, on T cell activation and differentiation. MetAp2 is an enzyme which regulates cellular protein synthesis and is highly expressed in T cells. Lodamin was found to suppress T cell receptor (TCR mediated T cell proliferation and reduced the production of Th1 and Th17 cells. Further, Lodamin suppressed overall inflammation in the mouse model of experimental autoimmune uveitis (EAU by a six fold. This effect was attributed in part to a reduction in retinal proinflammatory cytokines, down regulation of MetAP2 expression in purified lymph node CD4(+ T cells, and a general normalization of the systemic immune reaction.

  10. Suppression of Autoimmune Retinal Inflammation by an Antiangiogenic Drug

    Science.gov (United States)

    Bazinet, Lauren; D’Amato, Robert J.

    2013-01-01

    Chronic and recurrent uveitis account for approximately 10% of legal blindness in the western world. Autoimmune uveitis is driven by activated CD4+ T cells that differentiate into effector T helper cells (Th1, Th2, and Th17) which release proinflammatory cytokines that damage the retina. In this study we investigated the effect of the methionine aminopeptidase 2 (MetAP2) inhibitor, Lodamin, on T cell activation and differentiation. MetAp2 is an enzyme which regulates cellular protein synthesis and is highly expressed in T cells. Lodamin was found to suppress T cell receptor (TCR) mediated T cell proliferation and reduced the production of Th1 and Th17 cells. Further, Lodamin suppressed overall inflammation in the mouse model of experimental autoimmune uveitis (EAU) by a six fold. This effect was attributed in part to a reduction in retinal proinflammatory cytokines, down regulation of MetAP2 expression in purified lymph node CD4+ T cells, and a general normalization of the systemic immune reaction. PMID:23785488

  11. Puberty suppression in gender identity disorder: the Amsterdam experience.

    Science.gov (United States)

    Kreukels, Baudewijntje P C; Cohen-Kettenis, Peggy T

    2011-05-17

    The use of gonadotropin-releasing hormone analogs (GnRHa) to suppress puberty in adolescents with gender dysphoria is a fairly new intervention in the field of gender identity disorders or transsexualism. GnRHa are used to give adolescents time to make balanced decisions on any further treatment steps, and to obtain improved results in the physical appearance of those who opt to continue with sex reassignment. The effects of GnRHa are reversible. However, concerns have been raised about the risk of making the wrong treatment decisions, as gender identity could fluctuate during adolescence, adolescents in general might have poor decision-making abilities, and there are potential adverse effects on health and on psychological and psychosexual functioning. Proponents of puberty suppression emphasize the beneficial effects of GnRHa on the adolescents' mental health, quality of life and of having a physical appearance that makes it possible for the patients to live unobtrusively in their desired gender role. In this Review, we discuss the evidence pertaining to the debate on the effects of GnRHa treatment. From the studies that have been published thus far, it seems that the benefits outweigh the risks. However, more systematic research in this area is needed to determine the safety of this approach.

  12. Benzoxazole derivatives suppress lipopolysaccharide-induced mast cell activation.

    Science.gov (United States)

    Cho, Kyung-Ah; Park, Minhwa; Kim, Yu-Hee; Choo, Hea-Young Park; Lee, Kyung Ho

    2018-05-01

    Mast cells are central regulators of allergic inflammation that function by releasing various proallergic inflammatory mediators, including histamine, eicosanoids and proinflammatory cytokines. Occasionally, bacterial infections may initiate or worsen allergic inflammation. A number of studies have indicated that activation of lipoxygenase in mast cells positive regulates allergic inflammatory responses by generating leukotrienes and proinflammatory cytokines. In the present study, the effects of benzoxazole derivatives on the lipopolysaccharide (LPS)‑induced expression of proinflammatory cytokines, production of histamine and surface expression of co‑stimulatory molecules on bone marrow-derived mast cells (BMMCs) were studied. The benzoxazole derivatives significantly reduced the expression of interleukin (IL)‑1β, IL‑6, IL‑13, tumor necrosis factor‑α, perilipin (PLIN) 2, and PLIN3 in BMMCs treated with LPS. Furthermore, histamine production was suppressed in BMMCs treated with LPS, or treated with phorbol-12-myristate-13-acetate/ionomycin. Benzoxazole derivatives marginally affected the surface expression of cluster of differentiation (CD)80 and CD86 on BMMCs in the presence of LPS, although LPS alone did not increase the expression of those proteins. Therefore, benzoxazole derivatives inhibited the secretion of proinflammatory cytokines in mast cells and may be potential candidate anti‑allergic agents to suppress mast cell activation.

  13. Toxic releases from power plants

    International Nuclear Information System (INIS)

    Rubin, E.S.

    1999-01-01

    Beginning in 1998, electric power plants burning coal or oil must estimate and report their annual releases of toxic chemicals listed in the Toxics Release Inventory (TRI) published by the US Environmental Protection Agency (EPA). This paper identifies the toxic chemicals of greatest significance for the electric utility sector and develops quantitative estimates of the toxic releases reportable to the TRI for a representative coal-fired power plant. Key factors affecting the magnitude and types of toxic releases for individual power plants also are discussed. A national projection suggests that the magnitude of electric utility industry releases will surpass those of the manufacturing industries which current report to the TRI. Risk communication activities at the community level will be essential to interpret and provide context for the new TRI results

  14. Better and faster velocity pulsatility assessment in cerebral white matter perforating arteries with 7T quantitative flow MRI through improved slice profile, acquisition scheme, and postprocessing.

    Science.gov (United States)

    Geurts, Lennart; Biessels, Geert Jan; Luijten, Peter; Zwanenburg, Jaco

    2018-03-01

    A previously published cardiac-gated 2D Qflow protocol at 7 T in cerebral perforating arteries was optimized to reduce velocity underestimation and improve temporal resolution. First, the signal-to-noise ratio (SNR) gain of the velocity measurement (SNR v ) was tested for two signal averages versus one. Second, the decrease in velocity underestimation with a tilted optimized nonsaturating excitation (TONE) pulse was tested. Third, the decrease in pulsatility index (PI) underestimation through improved temporal resolution was tested. Test-retest agreement was measured for the resulting acquisition in older volunteers (mean age 63 years), and the results were compared with the other volunteers (mean age 26 years). Using two signal averages increased SNR v by only 12% (P = 0.04), probably due to motion of the subvoxel-size arteries. The TONE decreased velocity underestimation, thereby increasing the mean velocity from 0.52 to 0.67 cm/s (P < 0.001). The PI increased substantially with increasing temporal resolution. The test-retest agreement showed good coefficients of repeatability of 0.18 cm/s for velocity and 0.14 for PI. The measured velocity was lower in the older group: 0.42 versus 0.51 cm/s (P = 0.05). The optimized sequence yields better velocity and PI estimates in small vessels, has twice as good test-retest agreement, and has a suitable scan time for use in patients. Magn Reson Med 79:1473-1482, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for

  15. Endogenous Glucagon-like Peptide-1 Suppresses High-Fat Food Intake by Reducing Synaptic Drive onto Mesolimbic Dopamine Neurons

    Directory of Open Access Journals (Sweden)

    Xue-Feng Wang

    2015-08-01

    Full Text Available Glucagon-like peptide-1 (GLP-1 and its analogs act as appetite suppressants and have been proven to be clinically efficacious in reducing body weight in obese individuals. Central GLP-1 is expressed in a small population of brainstem cells located in the nucleus tractus solitarius (NTS, which project to a wide range of brain areas. However, it remains unclear how endogenous GLP-1 released in the brain contributes to appetite regulation. Using chemogenetic tools, we discovered that central GLP-1 acts on the midbrain ventral tegmental area (VTA and suppresses high-fat food intake. We used integrated pathway tracing and synaptic physiology to further demonstrate that activation of GLP-1 receptors specifically reduces the excitatory synaptic strength of dopamine (DA neurons within the VTA that project to the nucleus accumbens (NAc medial shell. These data suggest that GLP-1 released from NTS neurons can reduce highly palatable food intake by suppressing mesolimbic DA signaling.

  16. Physiologic Doses of Bilirubin Contribute to Tolerance of Islet Transplants by Suppressing the Innate Immune Response.

    Science.gov (United States)

    Adin, Christopher A; VanGundy, Zachary C; Papenfuss, Tracey L; Xu, Feng; Ghanem, Mostafa; Lakey, Jonathan; Hadley, Gregg A

    2017-01-24

    Bilirubin has been recognized as a powerful cytoprotectant when used at physiologic doses and was recently shown to have immunomodulatory effects in islet allograft transplantation, conveying donor-specific tolerance in a murine model. We hypothesized that bilirubin, an antioxidant, acts to suppress the innate immune response to islet allografts through two mechanisms: 1) by suppressing graft release of damage-associated molecular patterns (DAMPs) and inflammatory cytokines, and 2) by producing a tolerogenic phenotype in antigen-presenting cells. Bilirubin was administered intraperitoneally before pancreatic procurement or was added to culture media after islet isolation in AJ mice. Islets were exposed to transplant-associated nutrient deprivation and hypoxia. Bilirubin significantly decreased islet cell death after isolation and hypoxic stress. Bilirubin supplementation of islet media also decreased the release of DAMPs (HMGB1), inflammatory cytokines (IL-1β and IL-6), and chemokines (MCP-1). Cytoprotection was mediated by the antioxidant effects of bilirubin. Treatment of macrophages with bilirubin induced a regulatory phenotype, with increased expression of PD-L1. Coculture of these macrophages with splenocytes led to expansion of Foxp3+ Tregs. In conclusion, exogenous bilirubin supplementation showed cytoprotective and antioxidant effects in a relevant model of islet isolation and hypoxic stress. Suppression of DAMP release, alterations in cytokine profiles, and tolerogenic effects on macrophages suggest that the use of this natural antioxidant may provide a method of preconditioning to improve outcomes after allograft transplantation.

  17. Modulatory action of taurine on the release of GABA in cerebellar slices of the guinea pig

    Energy Technology Data Exchange (ETDEWEB)

    Namima, M.; Okamoto, K.; Sakai, Y.

    1983-01-01

    For the purpose of demonstrating the action of taurine as a neuromodulator in addition to its suggested neurotransmitter function, the effects of taurine and muscimol on the depolarization-induced Ca-dependent release of (/sup 3/H) gamma-aminobutyric acid ((/sup 3/H)GABA) and L-(/sup 3/H)glutamate in cerebellar slices from guinea pigs were investigated. The release of (/sup 3/H)GABA was found to be greatly decreased by a GABA agonist, muscimol, and by taurine, but not by glycine. The release of L-(/sup 3/H)glutamate was little affected by taurine. The release of (/sup 3/H)GABA, was enhanced by bicuculline and strychnine, but not by picrotoxin, and the suppressive action of muscimol on the GABA release was antagonized by bicuculline, picrotoxin, and strychnine, suggesting the possible existence of presynaptic autoreceptors for GABA in the cerebellum. The suppressive action of taurine on the release of (/sup 3/H)GABA, on the other hand, was blocked only by bicuculline. These results suggest that taurine reduced the release of (/sup 3/H)GABA from cerebellar slices by acting on the GABA autoreceptors or, more likely, on other types of receptors that are sensitive to bicuculline. As a possible mechanism for this modulatory action of taurine, the blockade by this amino acid of the influx of Ca/sup 2 +/ into cerebellar tissues was tentatively suggested.

  18. Evaluation of growth hormone release and human growth hormone treatment in children with cranial irradiation-associated short stature

    International Nuclear Information System (INIS)

    Romshe, C.A.; Zipf, W.B.; Miser, A.; Miser, J.; Sotos, J.F.; Newton, W.A.

    1984-01-01

    We studied nine children who had received cranial irradiation for various malignancies and subsequently experienced decreased growth velocity. Their response to standard growth hormone stimulation and release tests were compared with that in seven children with classic GH deficiency and in 24 short normal control subjects. With arginine and L-dopa stimulation, six of nine patients who received radiation had a normal GH response (greater than 7 ng/ml), whereas by design none of the GH deficient and all of the normal children had a positive response. Only two of nine patients had a normal response to insulin hypoglycemia, with no significant differences in the mean maximal response of the radiation and the GH-deficient groups. Pulsatile secretion was not significantly different in the radiation and GH-deficient groups, but was different in the radiation and normal groups. All subjects in the GH-deficient and radiation groups were given human growth hormone for 1 year. Growth velocity increased in all, with no significant difference in the response of the two groups when comparing the z scores for growth velocity of each subject's bone age. We recommend a 6-month trial of hGH in children who have had cranial radiation and are in prolonged remission with a decreased growth velocity, as there is no completely reliable combination of GH stimulation or release tests to determine their response

  19. Suppression of outgassing from spindt-type cold-cathode by heat treatment

    International Nuclear Information System (INIS)

    Miyo, Yasuhiko; Ogiwara, Norio; Saidoh, Masahiro; Hayashi, Naoki; Turuta, Kouichi.

    1995-01-01

    In Spindt type cold cathode electron source (hereafter, referred to as FEA), field emission is used for extracting electrons. It was made clear that the FEA is an excellent electron source that never causes gas release by heating peripheral parts. But the gas release form the FEA was confirmed though it was slight accompanying the extraction of current. This gas release becomes a problem when pressure measurement is carried out by using the FEA in ultrahigh or extremely high vacuum. If the gas release occurs by the effect of the heat generation at the tip of an emitter accompanying the extraction of electron current, it is possible to reduce the gas release by carrying out the heat treatment of the FEA was attempted, and as the result, it was elucidated that by the heat treatment at 400degC, the gas release form the FEA was able to be suppressed. However, a new problem that the insulation between gate and emitter deteriorated and broke during the extraction of current occurred. The experimental method and the results of the reduction of gas release by heat treatment and the observation of the broken FEA with a scanning electron microscope are reported. Also the problem that in the FEA which was heat-treated at 400degC, the current has decreased from 500 μA to 100 μA in about 100 hours occurred. As to these problems, it is necessary to continue the experiment further. (K.I.)

  20. Um sistema de ventrículo pulmonar produzindo pressão pulsátil em único ventrículo: modelo experimental A pulmonary ventricle system producing pulsatile pressure in single ventricle: experimental model

    Directory of Open Access Journals (Sweden)

    Bilgein Emrecan

    2006-09-01

    Full Text Available OBJETIVO: Pacientes com ventrículo único funcional têm prognóstico ruim, que resulta em insuficiência cardíaca, mesmo após tratamento cirúrgico. As operações derivação cavo-pulmonar (exceto pelas conexões do átrio direito ao ventrículo direito não apresentam sistema ventricular pulmonar com pressão pulsátil, além do fluxo reduzido ao ventrículo único. Para resolver o problema, tentamos criar um ventrículo pulmonar que produza pressão pulsátil experimentalmente. MÉTODO: Tentamos criar um sistema ventricular direito que produzisse pressão pulsátil. O modelo experimental foi realizado em seis ovelhas. As pressões do ventrículo pulmonar criado, da artéria pulmonar e do ventrículo esquerdo foram medidas após a saída da circulação extracorpórea. RESULTADOS: A média das pressões arteriais pulmonares sistólica e diastólica foi 15,6 ± 2,0 mmHg e 4,5 ± 1,5 mmHg. A média da pressão sistólica ventricular esquerda foi 76,6 ± 4,4 mmHg. CONCLUSÃO: Um ventrículo que produza pressão pulsátil é necessário para a regulação do fluxo da artéria pulmonar, com pressão venosa central e pressão pulmonar não pulsátil nas anomalias como ventrículos únicos funcionais.OBJECTIVE: Patients with functional single ventricle show bad survey, most of which result in cardiac failure even in the case that they are operated. The right heart bypass operations except for right atrium and right ventricle connections lack pulsatile pulmonary ventricle system besides the volume lack coming to the common ventricle. To solve the problem, we tried to create a pulmonary ventricle which produces pulsatile pressure experimentally. METHODS: We tried to form a right ventricle system which produces pulsatile pressure. The experimental model was carried on six sheep. The pressures of the created pulmonary ventricle, pulmonary artery and the left ventricle were measured after leaving the cardiopulmonary bypass. RESULTS: The mean of the

  1. Chondromalacia patellae: fat-suppressed MR imaging.

    Science.gov (United States)

    Rose, P M; Demlow, T A; Szumowski, J; Quinn, S F

    1994-11-01

    To evaluate the accuracy of fat-suppressed magnetic resonance (MR) imaging in diagnosing chondromalacia patellae. Seventy-one patients underwent fat-suppressed MR imaging and arthroscopy of the patellofemoral compartment. Findings were classified as early or advanced chondromalacia or as normal and were correlated with arthroscopic findings. Early and advanced stages of chondromalacia patellae were reliably detected, with positive predictive values of 85% and 92%, respectively. Specificity in early stages was 94% and in late stages was 98%. However, the overall accuracies did not differ substantially from those reported in studies that did not use fat-suppressed imaging. Axial, fat-suppressed MR imaging accurately depicts changes caused by chondromalacia patellae. Early stages can be seen as intrasubstance changes of increased signal intensity. Results of this study suggest a high degree of specificity in excluding both early and advanced changes.

  2. METHOD OF SUPPRESSING GASTROINTESTINAL UREASE ACTIVITY

    Science.gov (United States)

    Visek, W.J.

    1963-04-23

    This patent shows a method of increasing the growth rate of chicks. Certain diacyl substituted ureas such as alloxan, murexide, and barbituric acid are added to their feed, thereby suppressing gastrointestinal urease activity and thus promoting growth. (AEC)

  3. Suppression factors in diffractive photoproduction of dijets

    International Nuclear Information System (INIS)

    Klasen, Michael; Kramer, Gustav

    2010-06-01

    After new publications of H1 data for the diffractive photoproduction of dijets, which overlap with the earlier published H1 data and the recently published data of the ZEUS collaboration, have appeared, we have recalculated the cross sections for this process in next-to-leading order (NLO) of perturbative QCD to see whether they can be interpreted consistently. The results of these calculations are compared to the data of both collaborations. We find that the NLO cross sections disagree with the data, showing that factorization breaking occurs at that order. If direct and resolved contributions are both suppressed by the same amount, the global suppression factor depends on the transverse-energy cut. However, by suppressing only the resolved contribution, also reasonably good agreement with all the data is found with a suppression factor independent of the transverse-energy cut. (orig.)

  4. Attention modulates sensory suppression during back movements.

    Science.gov (United States)

    Van Hulle, Lore; Juravle, Georgiana; Spence, Charles; Crombez, Geert; Van Damme, Stefaan

    2013-06-01

    Tactile perception is often impaired during movement. The present study investigated whether such sensory suppression also occurs during back movements, and whether this would be modulated by attention. In two tactile detection experiments, participants simultaneously engaged in a movement task, in which they executed a back-bending movement, and a perceptual task, consisting of the detection of subtle tactile stimuli administered to their upper or lower back. The focus of participants' attention was manipulated by raising the probability that one of the back locations would be stimulated. The results revealed that tactile detection was suppressed during the execution of the back movements. Furthermore, the results of Experiment 2 revealed that when the stimulus was always presented to the attended location, tactile suppression was substantially reduced, suggesting that sensory suppression can be modulated by top-down attentional processes. The potential of this paradigm for studying tactile information processing in clinical populations is discussed. Copyright © 2013 Elsevier Inc. All rights reserved.

  5. Suppression of instability in rotatory hydromagnetic convection

    Indian Academy of Sciences (India)

    first time by Lord Rayleigh [9] for the idealized case of two free boundaries. Rayleigh's theory shows that the gravity-dominated thermal instability in liquid layer ... suppressed for oscillatory perturbations by the simultaneous application of a ...

  6. Combustion suppressing device for leaked sodium

    International Nuclear Information System (INIS)

    Ooto, Akihiro.

    1985-01-01

    Purpose: To suppress the atmospheric temperature to secure the building safety and shorten the recovery time after the leakage in a chamber for containing sodium leaked from coolant circuit equipments or pipeways of LMFBR type rector by suppressing the combustion of sodium contained in the chamber. Constitution: To the inner wall of a chamber for containing sodium handling equipments, are vertically disposed a panel having a coolant supply port at the upper portion and a coolant discharge port at the lower portion thereof and defined with a coolant flowing channel and a panel for sucking the coolant discharged from the abovementioned panel and exhausting the same externally. Further, a corrugated combustion suppressing plate having apertures for draining the condensated leaked sodium is disposed near the sodium handling equipments. If ruptures are resulted to the sodium handling equipments or pipeway, leaked sodium is passed through the drain apertures in the suppressing plate and stored at the bottom of the containing chamber. (Horiuchi, T.)

  7. Pest persistence and eradication conditions in a deterministic model for sterile insect release.

    Science.gov (United States)

    Gordillo, Luis F

    2015-01-01

    The release of sterile insects is an environment friendly pest control method used in integrated pest management programmes. Difference or differential equations based on Knipling's model often provide satisfactory qualitative descriptions of pest populations subject to sterile release at relatively high densities with large mating encounter rates, but fail otherwise. In this paper, I derive and explore numerically deterministic population models that include sterile release together with scarce mating encounters in the particular case of species with long lifespan and multiple matings. The differential equations account separately the effects of mating failure due to sterile male release and the frequency of mating encounters. When insects spatial spread is incorporated through diffusion terms, computations reveal the possibility of steady pest persistence in finite size patches. In the presence of density dependence regulation, it is observed that sterile release might contribute to induce sudden suppression of the pest population.

  8. Suppressing Tsetse Flies to Improve Lives

    International Nuclear Information System (INIS)

    Potterton, Louise; Pavlicek, Petr; Parker, Andrew

    2013-01-01

    In 2009, the government-run Southern Tsetse Eradication Project (STEP) in Ethiopia, with the support of the IAEA, started to carry out intensive activities to suppress the fly population using insecticides. The fly population is now down by 90%. The benefits of tsetse suppression can be seen all over the region. Diary produce is now widely available at markets and healthy animals can be seen everywhere in farming and transport

  9. Gamma camera scatter suppression unit WAM

    International Nuclear Information System (INIS)

    Kishi, Haruo; Shibahara, Noriyuki; Hirose, Yoshiharu; Shimonishi, Yoshihiro; Oumura, Masahiro; Ikeda, Hozumi; Hamada, Kunio; Ochi, Hironobu; Itagane, Hiroshi.

    1990-01-01

    In gamma camera imaging, scattered radiation is one of big factors to decrease image contrast. Simply, scatter suppression makes signal to noise ratio larger, but it makes statistics error because of radionuclide injection limit to the human body. EWA is a new method that suppresses scattered radiation and improves image contrast. In this article, WAM which is commercialized EWA method by Siemens Gammasonics Inc. is presented. (author)

  10. Release plan for Big Pete

    International Nuclear Information System (INIS)

    Edwards, T.A.

    1996-11-01

    This release plan is to provide instructions for the Radiological Control Technician (RCT) to conduct surveys for the unconditional release of ''Big Pete,'' which was used in the removal of ''Spacers'' from the N-Reactor. Prior to performing surveys on the rear end portion of ''Big Pete,'' it shall be cleaned (i.e., free of oil, grease, caked soil, heavy dust). If no contamination is found, the vehicle may be released with the permission of the area RCT Supervisor. If contamination is found by any of the surveys, contact the cognizant Radiological Engineer for decontamination instructions

  11. Commercial SNF Accident Release Fractions

    Energy Technology Data Exchange (ETDEWEB)

    J. Schulz

    2004-11-05

    The purpose of this analysis is to specify and document the total and respirable fractions for radioactive materials that could be potentially released from an accident at the repository involving commercial spent nuclear fuel (SNF) in a dry environment. The total and respirable release fractions are used to support the preclosure licensing basis for the repository. The total release fraction is defined as the fraction of total commercial SNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. Radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses; this subset of the total release fraction is referred to as the respirable release fraction. Accidents may involve waste forms characterized as: (1) bare unconfined intact fuel assemblies, (2) confined intact fuel assemblies, or (3) canistered failed commercial SNF. Confined intact commercial SNF assemblies at the repository are contained in shipping casks, canisters, or waste packages. Four categories of failed commercial SNF are identified: (1) mechanically and cladding-penetration damaged commercial SNF, (2) consolidated/reconstituted assemblies, (3) fuel rods, pieces, and debris, and (4) nonfuel components. It is assumed that failed commercial SNF is placed into waste packages with a mesh screen at each end (CRWMS M&O 1999). In contrast to bare unconfined fuel assemblies, the

  12. Commercial SNF Accident Release Fractions

    International Nuclear Information System (INIS)

    Schulz, J.

    2004-01-01

    The purpose of this analysis is to specify and document the total and respirable fractions for radioactive materials that could be potentially released from an accident at the repository involving commercial spent nuclear fuel (SNF) in a dry environment. The total and respirable release fractions are used to support the preclosure licensing basis for the repository. The total release fraction is defined as the fraction of total commercial SNF assembly inventory, typically expressed as an activity inventory (e.g., curies), of a given radionuclide that is released to the environment from a waste form. Radionuclides are released from the inside of breached fuel rods (or pins) and from the detachment of radioactive material (crud) from the outside surfaces of fuel rods and other components of fuel assemblies. The total release fraction accounts for several mechanisms that tend to retain, retard, or diminish the amount of radionuclides that are available for transport to dose receptors or otherwise can be shown to reduce exposure of receptors to radiological releases. The total release fraction includes a fraction of airborne material that is respirable and could result in inhalation doses; this subset of the total release fraction is referred to as the respirable release fraction. Accidents may involve waste forms characterized as: (1) bare unconfined intact fuel assemblies, (2) confined intact fuel assemblies, or (3) canistered failed commercial SNF. Confined intact commercial SNF assemblies at the repository are contained in shipping casks, canisters, or waste packages. Four categories of failed commercial SNF are identified: (1) mechanically and cladding-penetration damaged commercial SNF, (2) consolidated/reconstituted assemblies, (3) fuel rods, pieces, and debris, and (4) nonfuel components. It is assumed that failed commercial SNF is placed into waste packages with a mesh screen at each end (CRWMS M andO 1999). In contrast to bare unconfined fuel assemblies, the

  13. Suppression sours sacrifice: emotional and relational costs of suppressing emotions in romantic relationships.

    Science.gov (United States)

    Impett, Emily A; Kogan, Aleksandr; English, Tammy; John, Oliver; Oveis, Christopher; Gordon, Amie M; Keltner, Dacher

    2012-06-01

    What happens when people suppress their emotions when they sacrifice for a romantic partner? This multimethod study investigates how suppressing emotions during sacrifice shapes affective and relationship outcomes. In Part 1, dating couples came into the laboratory to discuss important romantic relationship sacrifices. Suppressing emotions was associated with emotional costs for the partner discussing his or her sacrifice. In Part 2, couples participated in a 14-day daily experience study. Within-person increases in emotional suppression during daily sacrifice were associated with decreases in emotional well-being and relationship quality as reported by both members of romantic dyads. In Part 3, suppression predicted decreases