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Sample records for analyzing pulsatile hormone

  1. A comparison of methods for analyzing time series of pulsatile hormone data.

    Science.gov (United States)

    Carlson, N E; Horton, K W; Grunwald, G K

    2013-11-20

    Many endocrine systems are regulated by pulsatile hormones - hormones that are secreted intermittently in boluses rather than continuously over time. To study pulsatile secretion, blood is drawn every few minutes for an extended period. The result is a time series of hormone concentrations for each individual. The goal is to estimate pulsatile hormone secretion features such as frequency, location, duration, and amount of pulsatile and non-pulsatile secretion and compare these features between groups. Various statistical approaches to analyzing these data have been proposed, but validation has generally focused on one hormone. Thus, we lack a broad understanding of each method's performance. By using simulated data with features seen in reproductive and stress hormones, we investigated the performance of three recently developed statistical approaches for analyzing pulsatile hormone data and compared them to a frequently used deconvolution approach. We found that methods incorporating a changing baseline modeled both constant and changing baseline shapes well; however, the added model flexibility resulted in a slight increase in bias in other model parameters. When pulses were well defined and baseline constant, Bayesian approaches performed similar to the existing deconvolution method. The increase in computation time of Bayesian approaches offered improved estimation and more accurate quantification of estimation variation in situations where pulse locations were not clearly identifiable. Within the class of deconvolution models for fitting pulsatile hormone data, the Bayesian approach with a changing baseline offered adequate results over the widest range of data.

  2. Active acromegaly enhances spontaneous parathyroid hormone pulsatility.

    Science.gov (United States)

    Mazziotti, Gherardo; Cimino, Vincenzo; De Menis, Ernesto; Bonadonna, Stefania; Bugari, Giovanna; De Marinis, Laura; Veldhuis, Johannes D; Giustina, Andrea

    2006-06-01

    In healthy subjects, parathyroid hormone (PTH) is secreted in a dual fashion, with low-amplitude and high-frequency pulses superimposed on tonic secretion. These 2 components of PTH secretion seem to have different effects on target organs. The aim of our study was to evaluate whether growth hormone excess in acromegaly may modify the spontaneous pulsatility of PTH. Five male patients with newly diagnosed active acromegaly and 8 healthy subjects were evaluated by 3-minute blood sampling for 6 hours. Plasma PTH concentrations were evaluated by multiparameter deconvolution analysis. Plasma PTH release profiles were also subjected to an approximate entropy (ApEn) estimate, which provides an ensemble measure of the serial regularity or orderliness of the release process. In acromegalic patients, baseline serum PTH values were not significantly different from those measured in the healthy subjects, as well as tonic PTH secretion rate, number of bursts, fractional pulsatile PTH secretion, and ApEn ratio. Conversely, PTH pulse half-duration was significantly longer in acromegalic patients vs healthy subjects (11.8+/-0.95 vs 6.9+/-1.6 minutes; P=.05), whereas PTH pulse mass showed a tendency (P=.06) to be significantly greater in acromegalic patients. These preliminary data suggest that growth hormone excess may affect PTH secretory dynamics in patients with acromegaly. Potentially negative bone effects of the modifications of PTH secretory pattern in acromegaly should be investigated.

  3. Single dose and pulsatile treatment with human growth hormone in growth hormone deficiency.

    OpenAIRE

    Smith, P J; Pringle, P J; Brook, C G

    1987-01-01

    The growth and growth hormone profiles in four children receiving three different regimens of treatment with human growth hormone (hGH) were compared. There was no significant difference in the rate of growth between the regimens; the rate of growth fell dramatically after treatment. Pulsatile administration of hGH was no better than conventional treatment.

  4. One hundred pregnancies after treatment with pulsatile luteinizing-hormone releasing hormone to induce ovulation

    OpenAIRE

    Homburg, R.; Eshel, A.; Armar, NA; Tucker, M.; Mason, PW; Adams, J.; Kilborn, J.; Sutherland, IA; Jacobs, HS

    1989-01-01

    OBJECTIVE--To review treatment with pulsatile luteinising hormone releasing hormone in infertile women who do not ovulate and are resistant to clomiphene after 100 pregnancies achieved with this treatment. DESIGN--Retrospective analysis of 146 courses of treatment over 434 cycles. SETTING--Infertility clinic. PATIENTS--118 Women whose failure to ovulate was due to idiopathic hypogonadotrophic hypogonadism (n = 39), amenorrhoea related to low weight (n = 17), organic pituitary disease (n = 15)...

  5. Pulsatile glycoprotein hormone secretion in glycoprotein-producing pituitary tumors.

    Science.gov (United States)

    Samuels, M H; Henry, P; Kleinschmidt-Demasters, B K; Lillehei, K; Ridgway, E C

    1991-12-01

    To study patterns of hormone production and secretion in glycoprotein-producing pituitary tumors, 12 patients with such tumors underwent the following studies. Preoperatively, all patients had serum TSH, LH, FSH, and alpha-subunit levels measured every 15 min for 24 h. Hormone pulses were located by cluster analysis, and pulse parameters were compared to those in healthy young men, healthy young women, healthy postmenopausal women, and subjects with primary hypothyroidism. After surgery, immunocytochemistry for the four glycoproteins was performed on all tumors, and Northern blot analysis was performed in six tumors with probes for the four subunits. By immunocytochemistry, 42% of the tumors were positive for TSH beta, 83% for LH beta, 75% for FSH beta, and 92% for alpha-subunit. Preoperative serum hormone levels varied widely between patients and were not well correlated with the intensity of immunocytochemical staining. Northern blot analysis did not appear to be as sensitive as immunocytochemistry for detection of the glycoproteins. All patients had pulsatile glycoprotein secretion, with pulses of normal frequency but varied amplitude. These results suggest that in patients with glycoprotein tumors, hormone pulses may be an integral part of autonomous secretion, or that hypothalamic control is involved in glycoprotein secretion and, perhaps, in the pathogenesis of these tumors. PMID:1955510

  6. Endogenous opiates modulate the pulsatile secretion of biologically active luteinizing hormone in man.

    Science.gov (United States)

    Veldhuis, J D; Rogol, A D; Johnson, M L

    1983-12-01

    We studied the secretion of physiological pools of immunoreactive and biologically active luteinizing hormone in response to endogenous pulses of gonadotropin-releasing hormone (GNRH) in eugonadal men. Concentrations of immunoactive and bioactive luteinizing hormone (LH) were determined in blood drawn at 20-min intervals for 8 h in eight normal men under two conditions: (a) after placebo, in order to evaluate spontaneous LH pulsations in the basal state, and (b) after administration of the opiate-receptor antagonist, naltrexone, which is believed to amplify the pulsatile release of endogenous GNRH. Spontaneous and naltrexone-stimulated secretion of LH occurred in pulses of high biological activity, as measured in the RICT (rat interstitial cell testosterone bioassay), i.e., bioactive:immunoactive LH ratios within both spontaneous and naltrexone-stimulated LH pulses were higher than corresponding interpulse ratios (P less than 0.001). Quantitative characterization of the pulsatile release of bioactive LH revealed the following specific effects of opiate-receptor blockade: increased 8-h mean and integrated serum concentrations of bioactive LH (P less than 0.002), enhanced pulse frequency of bioactive LH release (P less than 0.001), and augmented peak amplitude of bio-LH pulses (P less than 0.01). Moreover, this increase in episodic secretion of bioactive LH was associated with increased 8-h mean and integrated serum testosterone concentrations in these men (P less than 0.05). We conclude the following: (a) LH is normally released in spontaneous pulses of high biological activity in men; (b) when the endogenous GNRH signal is amplified by opiate-receptor blockade, the pituitary gland releases more frequent bioactive LH pulses, which are of high amplitude and contain a high bioactive:immunoactive LH ratio. This increase in pulsatile release of bioactive LH quantitated in the RICT assay in vitro is reflected by acutely increased serum testosterone concentrations in vivo

  7. Role of endogenous opiates in the expression of negative feedback actions of androgen and estrogen on pulsatile properties of luteinizing hormone secretion in man.

    OpenAIRE

    Veldhuis, J D; Rogol, A D; Samojlik, E; Ertel, N H

    1984-01-01

    We have tested the participation of endogenous opiate pathways in the negative feedback actions of gonadal steroids on pulsatile properties of luteinizing (LH) hormone release in normal men. To this end, sex steroid hormones were infused intravenously at dosages that under steady state conditions selectively suppressed either the frequency or the amplitude of the pulsatile LH signal. The properties of pulsatile LH secretion were assessed quantitatively by computerized analysis of LH series de...

  8. Frequency-Dependent Regulation of Follicle-Stimulating Hormone β by Pulsatile Gonadotropin-Releasing Hormone Is Mediated by Functional Antagonism of bZIP Transcription Factors ▿

    Science.gov (United States)

    Ciccone, Nick A.; Xu, Shuyun; Lacza, Charlemagne T.; Carroll, Rona S.; Kaiser, Ursula B.

    2010-01-01

    Oscillatory synthesis and secretion of the gonadotropins, follicle-stimulating hormone (FSH) and luteinizing hormone (LH), under the control of pulsatile hypothalamic gonadotropin-releasing hormone (GnRH), is essential for normal reproductive development and fertility. The molecular mechanisms by which various patterns of pulsatile GnRH regulate gonadotrope responsiveness remain poorly understood. In contrast to the α and LHβ subunit genes, FSHβ subunit transcription is preferentially stimulated at low rather than high frequencies of pulsatile GnRH. In this study, mutation of a cyclic AMP response element (CRE) within the FSHβ promoter resulted in the loss of preferential GnRH stimulation at low pulse frequencies. We hypothesized that high GnRH pulse frequencies might stimulate a transcriptional repressor(s) to attenuate the action of CRE binding protein (CREB) and show that inducible cAMP early repressor (ICER) fulfills such a role. ICER was not detected under basal conditions, but pulsatile GnRH stimulated ICER to a greater extent at high than at low pulse frequencies. ICER binds to the FSHβ CRE site to reduce CREB occupation and abrogates both maximal GnRH stimulation and GnRH pulse frequency-dependent effects on FSHβ transcription. These data suggest that ICER production antagonizes the stimulatory action of CREB to attenuate FSHβ transcription at high GnRH pulse frequencies, thereby playing a critical role in regulating cyclic reproductive function. PMID:20008557

  9. Effects of a Growth Hormone-Releasing Hormone Analog on Endogenous GH Pulsatility and Insulin Sensitivity in Healthy Men

    OpenAIRE

    Stanley, Takara L.; Chen, Cindy Y.; Branch, Karen L.; Makimura, Hideo; GRINSPOON, Steven K.

    2010-01-01

    Context and Objective: Strategies to augment pulsatile GH may be beneficial in patients with excess visceral adiposity, in whom GH secretion is reduced. The objective of this study was to determine the effects of a novel GHRH (GHRH1–44) analog, tesamorelin, on endogenous GH pulsatility and insulin sensitivity in healthy men.

  10. Negative feedback regulation of pulsatile growth hormone secretion by insulin-like growth factor I. Involvement of hypothalamic somatostatin.

    OpenAIRE

    Bermann, M; Jaffe, C A; Tsai, W.; DeMott-Friberg, R; Barkan, A. L.

    1994-01-01

    To investigate the mechanisms of the negative feedback inhibition of growth hormone (GH) secretion by IGF-I, we studied parameters of GH pulsatility in six normal, fed men before and during a 48-h infusion of recombinant human IGF-I (rhIGF-I) (10-15 micrograms/kg per h). Plasma levels of IGF-I increased from the baseline value of 163.5 +/- 9.3 micrograms/liter (mean +/- SE) to a new steady state of 452.0 +/- 20.9 micrograms/liter during the infusion. Plasma GH concentrations were measured eve...

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

    International Nuclear Information System (INIS)

    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 E2 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 E2-mediated release of LHRH

  12. Interleukin 1. alpha. inhibits prostaglandin E sub 2 release to suppress pulsatile release of luteinizing hormone but not follicle-stimulating hormone

    Energy Technology Data Exchange (ETDEWEB)

    Rettori, V.; McCann, S.M. (Univ. of Texas Southwestern Medical Center, Dallas (United States)); Gimeno, M.F. (CEFYBO, Buenos Aires (Argentina)); Karara, A. (Vanderbilt Univ., Nashville, TN (United States)); Gonzalez, M.C. (Univ. de La Laguno, Tenerife (Spain))

    1991-04-01

    Interleukin 1{alpha} (IL-1{alpha}), 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-1{alpha} 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-1{alpha} 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-1{alpha} (10 pM) and the release of LH-releasing hormone (LHRH) and prostaglandin E{sub 2} into the medium was measured by RIA in the presence or absence of nonrepinephrine. 1{alpha} reduced basal LHRH release and blocked LHRH release induced by nonrepinephrine. In conclusion, IL-1{alpha} 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{sub 2}-mediated release of LHRH.

  13. Endogenous opiates modulate the pulsatile secretion of biologically active luteinizing hormone in man.

    OpenAIRE

    Veldhuis, J D; Rogol, A D; Johnson, M. L.

    1983-01-01

    We studied the secretion of physiological pools of immunoreactive and biologically active luteinizing hormone in response to endogenous pulses of gonadotropin-releasing hormone (GNRH) in eugonadal men. Concentrations of immunoactive and bioactive luteinizing hormone (LH) were determined in blood drawn at 20-min intervals for 8 h in eight normal men under two conditions: (a) after placebo, in order to evaluate spontaneous LH pulsations in the basal state, and (b) after administration of the op...

  14. Different effects of subnormal levels of progesterone on the pulsatile and surge mode secretion of luteinizing hormone in ovariectomized goats.

    Science.gov (United States)

    Kim, Seungjoon; Tanaka, Tomomi; Kamomae, Hideo

    2003-07-01

    This study tested the hypothesis that endocrinological threshold levels of progesterone that induce negative feedback effects on the pulsatile and surge modes of LH secretion are different. Our approach was to examine the effects of subnormal progesterone concentrations on LH secretion. Long-term ovariectomized Shiba goats that had received implants of silastic capsules containing estradiol were divided into three groups. The high progesterone (high P) group received a subcutaneous implant of a silastic packet (50 x 70 mm) containing progesterone, and the low progesterone (low P) group received a similar implant of a small packet (25 x 40 mm) containing progesterone. The control (non-P) group received no treatment with exogenous progesterone. Blood samples were collected daily throughout the experiment for the analysis of gonadal steroid hormone levels and at 10-min intervals for 8 h on Days 0, 3, and 7 (Day 0: just before progesterone treatment) for analysis of the pulsatile frequency of LH secretion. Then estradiol was infused into the jugular vein of all animals at a rate of 3 microg/h for 16 h on Day 8 to determine whether an LH surge was induced. Blood samples were collected every 2 h from 4 h before the start of the estradiol infusion until 48 h after the start of the infusion. In each group, the mean +/- SEM concentration after progesterone implant treatment was 3.3 +/- 0.1 ng/ml for the high P group, 1.1 +/- 0.1 ng/ml for the low P group, and <0.1 ng/ml for the non-P group, concentrations similar to the luteal levels, subluteal levels, and follicular phase levels of the normal estrous cycle, respectively. The estradiol concentration ranged from 4 to 8 pg/ml after estradiol capsule implants in all groups. The LH pulse frequency was significantly (P < 0.05) suppressed on Day 3 (6.2 +/- 0.5 pulses/8 h) and on Day 7 (2.6 +/- 0.9 pulses/8 h) relative to Day 0 (9.0 +/- 0.5 pulses/8 h) in the high P group. In both the low P and non-P groups, however, the changes

  15. Evaluation of pulsatile plasma concentrations of growth hormone in healthy dogs and dogs with dilated cardiomyopathy

    NARCIS (Netherlands)

    Beijerink, N.J.; Lee, W.M.; Stokhof, A.A.; Voorhout, G.; Mol, J.A.; Kooistra, H.S.

    2011-01-01

    Abstract OBJECTIVE: To evaluate plasma concentrations of growth hormone (GH) and insulin-like growth factor I (IGF-I) in healthy dogs and large-breed dogs with dilated cardiomyopathy (DCM). ANIMALS: 8 dogs with DCM and 8 healthy control dogs of comparable age and body weight. PROCEDURES: Blood sampl

  16. Effects of alcohol on pulsatile luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion in the adult male rat

    Energy Technology Data Exchange (ETDEWEB)

    Badger, T.M.; Abdallah, M.M.; Hayden, J.B. (Univ. of Arkansas for Medical Sciences, Little Rock (USA))

    1989-02-09

    To determine possible hypothalamic actions of alcohol on hormone secretion, the effects of acute intragastric alcohol on plasma LH and FSH pulsations were studied. One jugular and one intragastric cannula were surgically implanted into adult male Sprague Dawley rats. Eight days later, rats were bilaterally castrated at 1400 h and infused intragastrically with either saline or 3 g/kg ethanol between 0700 h 0800 h the next days. Blood samples (300 microliters) were collected every 5 min for 3 h (starting at 0800 h), centrifuged and the plasma was frozen for LH and FSH radioimmunoassay. The blood cells were resuspended in saline and returned to the animal immediately following the next sample collection. While the mean plasma LH or FSH concentration did not vary significantly between the alcohol-treated and saline-treated rats, the mean LH (but not FSH) pulse frequency was lower in ethanol-treated rats (3.3 {plus minus} 0.25 pulses/3 h) than saline-treated controls (7.2 {plus minus} 0.3 pulses/3 h). In addition, mean area under the OH pulses were significantly greater in ethanol-treated than saline controls. These data suggest that: (1) ethanol acts to reduce the frequency of LHRH release for the hypothalamus and increase the area under each LH pulse; and (2) LH and FSH secretion are differentially regulated.

  17. Actions of NPY, and its Y1 and Y2 receptors on pulsatile growth hormone secretion during the fed and fasted state.

    Science.gov (United States)

    Huang, Lili; Tan, Hwee Y; Fogarty, Matthew J; Andrews, Zane B; Veldhuis, Johannes D; Herzog, Herbert; Steyn, Frederik J; Chen, Chen

    2014-12-01

    The hypothalamic NPY system plays an important role in regulating food intake and energy expenditure. Different biological actions of NPY are assigned to NPY receptor subtypes. Recent studies demonstrated a close relationship between food intake and growth hormone (GH) secretion; however, the mechanism through which endogenous NPY modulates GH release remains unknown. Moreover, conclusive evidence demonstrating a role for NPY and Y-receptors in regulating the endogenous pulsatile release of GH does not exist. We used genetically modified mice (germline Npy, Y1, and Y2 receptor knock-out mice) to assess pulsatile GH secretion under both fed and fasting conditions. Deletion of NPY did not impact fed GH release; however, it reversed the fasting-induced suppression of pulsatile GH secretion. The recovery of GH secretion was associated with a reduction in hypothalamic somatotropin release inhibiting factor (Srif; somatostatin) mRNA expression. Moreover, observations revealed a differential role for Y1 and Y2 receptors, wherein the postsynaptic Y1 receptor suppresses GH secretion in fasting. In contrast, the presynaptic Y2 receptor maintains normal GH output under long-term ad libitum-fed conditions. These data demonstrate an integrated neural circuit that modulates GH release relative to food intake, and provide essential information to address the differential roles of Y1 and Y2 receptors in regulating the release of GH under fed and fasting states.

  18. 促性腺激素释放激素脉冲治疗的研究进展%Research progress of pulsatile gonadotrophin releasing hormone therapy

    Institute of Scientific and Technical Information of China (English)

    符梅(综述); 徐克惠(审校)

    2015-01-01

    Pulsatile gonadotrophin releasing hormone (GnRH)therapy is to stimulate pituitary gland to produce physiological gonadotropin by ntravenous or subcutaneous infusion which giving GnRH analogue in pulsation.Sequentially,gonadotropin could promote development of gonad,compound sex hormone, make reproductive cell growth and mature.Pulsatile GnRH therapy is particularly appropriate for patients with idiopathic hypogonadotropic hypogonadism (IHH)whose lesion is located hypothalamus with normal pituitary function.Pulsatile GnRH therapy could produce physiological positive and negative regulation, which are adjacent to physiological regulation mechanism in hypothalamic-pituitary-gonadal axis.Pulsatile GnRH therapy is a good way to treat infertility,becoming a research focus.This article reviews literatures on the characteristics,clinical applications,therapeutic dosage and frequency,influence factors,advantages and disadvantages of pulsatile GnRH therapy.%促性腺激素释放激素(GnRH)脉冲治疗是通过静脉滴注或者皮下给药的方式连续脉冲式给予 GnRH 类似物,兴奋垂体产生接近生理性的促性腺激素脉冲,进一步促进性腺发育,合成性激素并维持生殖细胞发育及成熟。GnRH 脉冲治疗尤其适用于下丘脑病变,且垂体功能正常而导致的低促性腺激素型性腺功能减退症(IHH)患者,GnRH 脉冲治疗方案最接近下丘脑-垂体-性腺轴的生理调节机制,可以模拟正常的生理模式产生内源性的正、负反馈调节。GnRH 脉冲治疗是治疗不孕不育的满意方法,也是目前学者研究的热点。笔者拟就 GnRH 脉冲分泌的特点,GnRH 脉冲治疗的应用、治疗剂量和频率、影响因素、优点及缺点进行综述如下。

  19. Role of endogenous opiates in the expression of negative feedback actions of androgen and estrogen on pulsatile properties of luteinizing hormone secretion in man.

    Science.gov (United States)

    Veldhuis, J D; Rogol, A D; Samojlik, E; Ertel, N H

    1984-07-01

    We have tested the participation of endogenous opiate pathways in the negative feedback actions of gonadal steroids on pulsatile properties of luteinizing (LH) hormone release in normal men. To this end, sex steroid hormones were infused intravenously at dosages that under steady state conditions selectively suppressed either the frequency or the amplitude of the pulsatile LH signal. The properties of pulsatile LH secretion were assessed quantitatively by computerized analysis of LH series derived from serial blood sampling over 12 h of observation. When the pure (nonaromatizable) androgen, 5-alpha-dihydrotestosterone, was infused continuously for 108 h at the blood production rate of testosterone, we were able to achieve selective inhibition of LH pulse frequency akin to that observed in experimental animals after low-dosage androgen replacement. Under these conditions, serum concentrations of testosterone and estradiol-17 beta did not change significantly, but serum 5 alpha-dihydrotestosterone concentrations increased approximately two- to threefold, with a corresponding increase in levels of its major metabolite, 5 alpha-androstan-3 alpha, 17 beta-diol. In separate experiments, the infusion of estradiol-17 beta at its blood production rate over a 4.5-d interval selectively suppressed LH pulse amplitude without influencing LH pulse frequency. Estrogen infusion increased serum estradiol-17 beta levels approximately twofold without significantly altering blood androgen concentrations. We then used these schedules of selective androgen or estrogen infusion to investigate the participation of endogenous opiates in the individual inhibitory feedback actions of pure androgen or estrogen on pulsatile LH release by administering a potent and specific opiate-receptor antagonist, naltrexone, during the infusions. Our observations indicate that, despite the continuous infusion of a dosage of 5 alpha-dihydrotestosterone that significantly suppresses LH pulse frequency, co

  20. Basal, But Not Pulsatile, Growth Hormone Secretion Determines the Ambient Circulating Levels of Insulin-Like Growth Factor-I

    OpenAIRE

    Faje, Alexander T.; Barkan, Ariel L.

    2010-01-01

    Context: Previous studies have shown that mean 24-h GH concentrations determine plasma IGF-I levels in patients with acromegaly. However, we have recently shown that continuous GH infusion, mimicking the interpulse GH levels, was significantly more effective than the pulsatile GH administration at increasing IGF-I concentrations.

  1. Jointly amplified basal and pulsatile growth hormone (GH) secretion and increased process irregularity in women with anorexia nervosa: indirect evidence for disruption of feedback regulation within the GH-insulin-like growth factor I axis

    DEFF Research Database (Denmark)

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

    1999-01-01

    pulsatility in AN using the techniques of deconvolution analysis and approximate entropy, which quantify secretory activity and serial irregularity of underlying hormone release not reflected in peak occurrence or amplitudes. To this end, 24-h GH profiles were obtained by continuous blood sampling aliquoted....... Accordingly, GH secretion in AN probably reflects altered neuroendocrine feedback regulation, e.g. associated with increased hypothalamic GHRH discharge superimposed on reduced hypothalamic somatostatinergic tone....

  2. Glucocorticoid pulsatility : implications for brain functioning

    NARCIS (Netherlands)

    Sarabdjitsingh, Ratna Angela

    2010-01-01

    Pronounced ultradian and circadian rhythms in the hormones of the hypothalamic-pituitary-adrenal (HPA) axis (i.e. glucocorticoids), one of the body’s major neuroendocrine axes, were already demonstrated several decades ago. Until now, the clinical relevance of the pulsatile nature of glucocorticoids

  3. Objective pulsatile tinnitus

    OpenAIRE

    Yacovino, Dario A.; Casas, Pablo

    2015-01-01

    Key Clinical Message Tinnitus is the usually unwanted perception of sound, in most cases there is no genuine physical source of sound. Less than 10% of tinnitus patients suffer from pulsatile tinnitus. Objective Pulsatile tinnitus can also be the first indication of dural arteriovenous fistula, so examination for such vascular origin must be performed.

  4. 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.

  5. Human growth hormone and prolactin secreting pituitary adenomas analyzed by in situ hybridization.

    Science.gov (United States)

    Lloyd, R V; Cano, M; Chandler, W F; Barkan, A L; Horvath, E; Kovacs, K

    1989-03-01

    Acidophilic pituitary adenomas commonly produce growth hormone (GH) or prolactin (PRL), according to studies employing immunohistochemical and ultrastructural methods. To examine this question, in situ hybridization with oligonucleotide probes was done on routinely processed tissues received in the pathology laboratory to analyze for the presence of GH and PRL messenger RNA (mRNA) in 4 normal pituitaries, 10 prolactinomas, and 16 GH-secreting adenomas. Most acidophilic cells in normal pituitaries expressed either GH or PRL hormone and the respective mRNAs, but GH mRNA and PRL hormone were also detected in some of the same cells. Patients with a clinical diagnosis of prolactinoma had cells with only PRL mRNA in their tumors, while most (14 of 16) patients with a clinical diagnosis of acromegaly or gigantism had both GH and PRL mRNAs in their tumors. The GH adenomas varied in these studies. In situ hybridization was helpful in characterizing the adenoma from a patient with acromegaly who had immunoreactive PRL, but no immunoreactive GH in the resected tumor; in situ hybridization analysis revealed mRNAs for both GH and PRL in the same tumor cells. Our findings indicate that pituitary adenomas from patients with acromegaly commonly express PRL mRNA. It is concluded that in situ hybridization provides new information about the clinical biology and the histopathologic classification of pituitary adenomas. PMID:2466405

  6. Abscisic acid signaling: thermal stability shift assays as tool to analyze hormone perception and signal transduction.

    Directory of Open Access Journals (Sweden)

    Fen-Fen Soon

    Full Text Available Abscisic acid (ABA is a plant hormone that plays important roles in growth and development. ABA is also the central regulator to protect plants against abiotic stresses, such as drought, high salinity, and adverse temperatures, and ABA signaling is therefore a promising biotechnological target for the generation of crops with increased stress resistance. Recently, a core signal transduction pathway has been established, in which ABA receptors, type 2C protein phosphatases, and AMPK-related protein kinases control the regulation of transcription factors, ion channels, and enzymes. Here we use a simple protein thermal stability shift assay to independently validate key aspects of this pathway and to demonstrate the usefulness of this technique to detect and characterize very weak (Kd ≥ 50 µM interactions between receptors and physiological and synthetic agonists, to determine and analyze protein-protein interactions, and to screen small molecule inhibitors.

  7. Hormones

    Science.gov (United States)

    Hormones are your body's chemical messengers. They travel in your bloodstream to tissues or organs. They work ... glands, which are special groups of cells, make hormones. The major endocrine glands are the pituitary, pineal, ...

  8. Efecto de melatonina sobre la secreción pulsátil de hormona luteinizante y de hormona del crecimiento en borregas con restricción alimenticia Effect of melatonin on the pulsatile luteinizing hormone and growth hormone secretion in ewe lambs under food restriction

    Directory of Open Access Journals (Sweden)

    S. E. RECABARREN

    2000-01-01

    Full Text Available El objetivo del presente trabajo fue caracterizar la secreción pulsátil de LH y GH en borregas sometidas a restricción alimenticia (n=5, grupo R-MEL, a las 20, 26 y 30 semanas de edad, tratadas diariamente con melatonina (3 mg/día, a las 16:00 h, desde las 10 semanas de edad. La restricción alimenticia se inició a las 16 semanas de edad. Borregas de la misma edad con restricción alimenticia sin administración de melatonina actuaron como grupo comparativo (n=6, R-SOL. El promedio transversal de LH tendió a aumentar desde 0,35± 0,04 a las 20 sem. hasta 0,61±0,15 ng/ml/6h a las 30 sem en las borregas del grupo R-MEL, mientras que en las borregas del grupo R-SOL el promedio no cambió entre ambas edades: 0,34± 0,03 a las 20 sem y 0,25±0,05 ng/ml/6h a las 30 sem. La frecuencia de pulsos de LH no cambió y no fue diferente entre los 2 grupos. La amplitud de pulsos de LH tendió a ser mayor en las borregas R-MEL a las 30 sem: 0,76± 0,28 y 0,38± 0,09 ng/ml respectivamente (PThe aim of the present work was to characterize the pulsatile LH and GH secretion in food restricted Suffolk ewe lambs (n=5, R-MEL group receiving daily oral administration of melatonin (3mg/20 mL, at 16:00 h, at 20-26- and 30 weeks of age, after 4,10 and 14 weeks of food restriction. Melatonin treatment was initiated at 10 weeks of age. Food restricted lambs of the same age, without melatonin treatment acted as comparative group (n=6, R-SOL. Blood samples were collected from a jugular vein by means of an indwelling catheter at 10 min-intervals for 6 hours, from 09:00 h. LH and GH were measured by radioimmunoassay. Plasma concentrations of both hormones were analyzed by the Cluster program to define pulse frequency (n° pulses/6h, and pulse amplitude (ng/mL. The transversal mean of LH and GH was also calculated (ng/mL/6h. In the R-MEL group, the transversal mean of LH tended to increase from 0.35± 0.04 in 20 weeks old lambs to 0.61± 0.15 ng/mL/6h in 30 weeks old

  9. ANALYSIS OF PULSATILE BLOOD FLOW IN AXIALLY MOVING ARTERIES

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In order to study motional properties of pulsatile blood flow in axially moving arteries, the authors derived some expressions of the pulsatile blood flow from the basic equations of motion for blood and vascular walls, including an axial blood velocity equation, a flow rate equation and a wall shear stress equation, which described not only the overall axial movement of the arteries but also the elastic properties of the vascular walls, discussed the effects of the arterial wall elasticity on the wall shear stress in coronary arteries in terms of these expressions, and analyzed changes of motional properties of pulsatile blood flow between an elastic arterial tube model and a rigid tube model. The results proved the inference by J.E. Moore Jr. et al. (1994) that the axial movement of arteries be as important in determining coronary artery hemodynamics as the elastic property of the vascular wall.

  10. CURRENT TRENDS IN PULSATILE DRUG DELIVERY SYSTEMS

    OpenAIRE

    S. R. Tajane et al.

    2012-01-01

    The purpose for this review on pulsatile drug delivery systems (PDDS) is to compile the recent literatures with special focus on the different types and approaches involved in the development of the formulation. Pulsatile drug delivery system is the most interesting time and site-specific system. This system is designed for chronopharmacotherapy. Thus, to mimic the function of living systems and in view of emerging chronotherapeutic approaches, pulsatile delivery, which is meant to release a ...

  11. ANALYSIS OF PULSATILE FLOW IN THE PARALLEL-PLATE FLOW CHAMBER WITH SPATIAL SHEAR STRESS GRADIENT

    Institute of Scientific and Technical Information of China (English)

    QIN Kai-rong; HU Xu-qu; LIU Zhao-rong

    2007-01-01

    The Parallel-Plate Flow Chamber (PPFC), of which the height is far smaller than its own length and width, is one of the main apparatus for the in-vitro study of the mechanical behavior of cultured vascular Endothelical Cells (ECs) exposed to fluid shear stress. The steady flow in different kinds of PPFC has been extensively investigated, whereas, the pulsatile flow in the PPFC has little attention. In consideration of the characteristics of geometrical size and pulsatile flow in the PPFC, the 3-D pulsatile flow was decomposed into a 2-D pulsatile flow in the vertical plane, and an incompressible plane potential flow in the horizontal plane. A simple method was then proposed to analyze the pulsatile flow in the PPFC with spatial shear stress gradient. On the basis of the method, the pulsatile fluid shear stresses in several reported PPFCs with spatial shear stress gradients were calculated. The results were theoretically meaningful for applying the PPFCs in-vitro, to simulate the pulsatile fluid shear stress environment, to which cultured ECs were exposed.

  12. PULSATILE DRUG DELIVERY SYSTEM: A REVIEW

    OpenAIRE

    Jamil Faraz; Singh Arjun; Kumar Sunil; Sharma Ritika

    2012-01-01

    The purpose for this review on pulsatile drug delivery systems (PDDS) is to compile the recent literatures with special focus on the different types and approaches involved in the development of the formulation. Pulsatile drug delivery system is the most interesting time and site-specific system. Diseases wherein PDDS are promising include asthma, peptic ulcer, cardiovascular diseases, arthritis,attention deficit syndrome in children, and hypercholesterolemia. PDDS can be classified into time...

  13. [Hematologic and endocrinologic effects of pulsatile cardiopulmonary bypass using a centrifugal pump].

    Science.gov (United States)

    Komoda, T; Maeta, H; Imawaki, S; Shiraishi, Y; Tanaka, S

    1992-06-01

    The effects of pulsatile and nonpulsatile flow during cardiopulmonary bypass (CPB) with of centrifugal pump (Sarns) and membrane oxygenator, on blood cells, hemodynamics, and hormonal response were studied. In the pulsatile group (group P) in which pulsatile flow was generated by centrifugal pump and a 20 Fr arterial cannula was used, hemolysis and reduction of platelet count during CPB were more marked than in the nonpulsatile group (group NP), in which the same type of circuit was used. When the 20 Fr arterial cannula was replaced with a 24 Fr cannula (group Pc), the rate of hemolysis during CPB was significantly reduced compared with that in group P (p less than 0.05). The rate of rise in plasma free hemoglobin from 10 to 70 minutes CPB in group Pc was 15.0 mg/dl/hr, this value did not exceed that in either group NP or in group Pr, in which a roller pump rather than centrifugal pump was used to generate pulsatile flow. These findings show that pulsatile CPB with a centrifugal pump produces no deleterious hematologic effect in clinical use. The rise in the level of angiotensin II in group P was significantly smaller than that in group NP (p less than 0.05), and the rise in plasma renin activity and levels of angiotensin I, adrenalin and noradrenaline were smaller than those in group NP, although these differences were no significance. These findings indicate that the centrifugal pump generates pulsatile flow effectively, although not so effectively as to prevent the rise in peripheral vascular resistance. During CPB, there was no change in levels of thyroid hormones, including free T3, free T4 and reverse T3, in either pulsatile groups P and Pc or nonpulsatile group. TSH level in group Pc was significantly elevated in contrast with that in the nonpulsatile group (p less than 0.05), in which no change in TSH level was seen. It is suggested that pulsatile perfusion using a centrifugal pump might maintain sufficient hypothalamic-pituitary function to permit

  14. 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.

  15. Hemodynamic responses to continuous versus pulsatile mechanical unloading of the failing left ventricle.

    Science.gov (United States)

    Bartoli, Carlo R; Giridharan, Guruprasad A; Litwak, Kenneth N; Sobieski, Michael; Prabhu, Sumanth D; Slaughter, Mark S; Koenig, Steven C

    2010-01-01

    Debate exists regarding the merits and limitations of continuous versus pulsatile flow mechanical circulatory support. To characterize the hemodynamic differences between each mode of support, we investigated the acute effects of continuous versus pulsatile unloading of the failing left ventricle in a bovine model. Heart failure was induced in male calves (n = 14). During an acute study, animals were instrumented through thoracotomy for hemodynamic measurement. A continuous flow (n = 8) and/or pulsatile flow (n = 8) left ventricular assist device (LVAD) was implanted and studied during maximum support ( approximately 5 L/min) and moderate support ( approximately 2-3 L/min) modes. Pulse pressure (PP), surplus hemodynamic energy (SHE), and (energy equivalent pressure [EEP]/mean aortic pressure (MAP) - 1) x 100% were derived to characterize hemodynamic energy profiles during the different support modes. Standard hemodynamic parameters of cardiac performance were also derived. Data were analyzed by repeated measures one-way analysis of variance within groups and unpaired Student's t-tests across groups. During maximum and moderate continuous unloading, PP, SHE, and (EEP/MAP - 1) x 100% were significantly decreased compared with baseline and compared with pulsatile unloading. As a result, continuous unloading significantly altered left ventricular peak systolic pressure, aortic systolic and diastolic pressure, +/-dP/dt, and rate x pressure product, whereas pulsatile unloading preserved a normal profile of physiologic values. As continuous unloading increased, the pressure-volume relationship collapsed, and the aortic valve remained closed. In contrast, as pulsatile unloading increased, a comparable decrease in left ventricular volumes was noted. However, a normal range of left ventricular pressures was preserved. Continuous unloading deranged the physiologic profile of myocardial and vascular hemodynamic energy utilization, whereas pulsatile unloading preserved more

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

    Energy Technology Data Exchange (ETDEWEB)

    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-/sup 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/sup -1/ during continuous infusion and varied between 95 and 501 pg x ml/sup -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.

  17. 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)

    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

  18. 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

  19. CURRENT TRENDS IN PULSATILE DRUG DELIVERY SYSTEMS

    Directory of Open Access Journals (Sweden)

    S. R. Tajane et al.

    2012-01-01

    Full Text Available The purpose for this review on pulsatile drug delivery systems (PDDS is to compile the recent literatures with special focus on the different types and approaches involved in the development of the formulation. Pulsatile drug delivery system is the most interesting time and site-specific system. This system is designed for chronopharmacotherapy. Thus, to mimic the function of living systems and in view of emerging chronotherapeutic approaches, pulsatile delivery, which is meant to release a drug following programmed lag phase, has increasing interest in the recent years. Diseases wherein PDDS are promising include asthma, peptic ulcer, cardiovascular diseases, arthritis, and attention deficit syndrome in children, cancer, diabetes, and hypercholesterolemia. Pulsatile drug delivery system divided into 2 types’ preplanned systems and stimulus induced system, preplanned systems based on osmosis, rupturable layers, and erodible barrier coatings. Stimuli induced system based on electrical, temperature and chemically induced systems. This review also summarizes some current PDDS already available in the market. These systems are useful to several problems encountered during the development of a pharmaceutical dosage form.

  20. Film coatings for oral pulsatile release.

    Science.gov (United States)

    Maroni, Alessandra; Zema, Lucia; Loreti, Giulia; Palugan, Luca; Gazzaniga, Andrea

    2013-12-01

    Pulsatile delivery is generally intended as a release of the active ingredient that is delayed for a programmable period of time to meet particular chronotherapeutic needs and, in the case of oral administration, also target distal intestinal regions, such as the colon. Most oral pulsatile delivery platforms consist in coated formulations wherein the applied polymer serves as the release-controlling agent. When exposed to aqueous media, the coating initially performs as a protective barrier and, subsequently, undergoes a timely failure based on diverse mechanisms depending on its physico-chemical and formulation characteristics. Indeed, it may be ruptured because of the gradual expansion of the core, swell and/or erode due to the glassy-rubbery polymer transition or become permeable thus allowing the drug molecules to diffuse outwards. Otherwise, when the coating is a semipermeable membrane provided with one or more orifices, the drug is released through the latter as a result of an osmotic water influx. The vast majority of pulsatile delivery systems described so far have been prepared by spray-coating, which offers important versatility and feasibility advantages over other techniques such as press- and dip-coating. In the present article, the design, manufacturing and performance of spray-coated pulsatile delivery platforms is thus reviewed. PMID:23506956

  1. Effects of the pulsatile flow settings on pulsatile waveforms and hemodynamic energy in a PediVAS centrifugal pump.

    Science.gov (United States)

    Wang, Shigang; Rider, Alan R; Kunselman, Allen R; Richardson, J Scott; Dasse, Kurt A; Undar, Akif

    2009-01-01

    The objective of this study was to test different pulsatile flow settings of the PediVAS centrifugal pump to seek an optimum setting for pulsatile flow to achieve better pulsatile energy and minimal backflow. The PediVAS centrifugal pump and the conventional pediatric clinical circuit, including a pediatric membrane oxygenator, arterial filter, arterial cannula, and 1/4 in circuit tubing were used. The circuit was primed with 40% glycerin water mixture. Postcannula pressure was maintained at 40 mm Hg by a Hoffman clamp. The experiment was conducted at 800 ml/min of pump flow with a modified pulsatile flow setting at room temperature. Pump flow and pressure readings at preoxygenator and precannula sites were simultaneously recorded by a data acquisition system. The results showed that backflows appeared at flow rates of 200-800 ml/min (200 ml/min increments) with the default pulsatile flow setting and only at 200 ml/min with the modified pulsatile flow setting. With an increased rotational speed difference ratio and a decreased pulsatile width, the pulsatility increased in terms of surplus hemodynamic energy and total hemodynamic energy at preoxygenator and precannula sites. Backflows seemed at preoxygenator and precannula sites at a 70% of rotational speed difference ratio. The modified pulsatile flow setting was better than the default pulsatile flow setting in respect to pulsatile energy and backflow. The pulsatile width and the rotational speed difference ratio significantly affected pulsatility. The parameter of the rotational speed difference ratio can automatically increase pulsatility with increased rotational speeds. Further studies will be conducted to optimize the pulsatile flow setting of the centrifugal pump.

  2. Defining pulsatility during continuous-flow ventricular assist device support.

    Science.gov (United States)

    Soucy, Kevin G; Koenig, Steven C; Giridharan, Guruprasad A; Sobieski, Michael A; Slaughter, Mark S

    2013-06-01

    Continuous-flow ventricular assist devices (CVADs) have gained widespread use as an effective clinical therapy for patients with advanced-stage heart failure. Axial and centrifugal CVADs have been successfully used as bridge-to-transplant and destination therapy. CVADs are smaller, more reliable, and less complex than the first-generation pulsatile-flow ventricular assist devices. Despite their recent clinical success, arteriovenous malformations, gastrointestinal bleeding, hemorrhagic strokes, aortic valve insufficiency, and valve fusion have been reported in heart failure patients supported by CVADs. It has been hypothesized that diminished arterial pressure and flow pulsatility delivered by CVAD may be a contributing factor to these adverse events. Subsequently, the clinical significance of vascular pulsatility continues to be highly debated. Studies comparing pulsatile-flow and continuous-flow support have presented conflicting findings, largely due to variations in device operation, support duration, and the criteria used to quantify pulsatility. Traditional measurements of pulse pressure and pulsatility index are less effective at quantifying pulsatility for mechanically derived flows, particularly with the growing trend of CVAD speed modulation to achieve various pulsatile flow patterns. Kinetic measurements of energy equivalent pressure and surplus hemodynamic energy can better quantify pulsatile energies, yet technologic and conceptual challenges are impeding their clinical adaption. A review of methods for quantifying vascular pulsatility and their application as a research tool for investigating physiologic responses to CVAD support are presented. PMID:23540401

  3. Pulsatile lipid vesicles under osmotic stress

    CERN Document Server

    Chabanon, Morgan; Liedberg, Bo; Parikh, Atul N; Rangamani, Padmini

    2016-01-01

    The response of lipid bilayers to osmotic stress is an important part of cellular function. Previously, in [Oglecka et al. 2014], we reported that cell-sized giant unilamellar vesicles (GUVs) exposed to hypotonic media, respond to the osmotic assault by undergoing a cyclical sequence of swelling and bursting events, coupled to the membrane's compositional degrees of freedom. Here, we seek to deepen our quantitative understanding of the essential pulsatile behavior of GUVs under hypotonic conditions, by advancing a comprehensive theoretical model for vesicle dynamics. The model quantitatively captures our experimentally measured swell-burst parameters for single-component GUVs, and reveals that thermal fluctuations enable rate dependent pore nucleation, driving the dynamics of the swell-burst cycles. We further identify new scaling relationships between the pulsatile dynamics and GUV properties. Our findings provide a fundamental framework that has the potential to guide future investigations on the non-equili...

  4. Arterial tree asymmetry reduces cerebral pulsatility.

    Science.gov (United States)

    Vrselja, Zvonimir; Brkic, Hrvoje; Curic, Goran

    2015-11-01

    With each heartbeat, pressure wave (PW) propagates from aorta toward periphery. In cerebral circulation, at the level of circle of Willis (CW), four arteries and four PWs converge. Since the interference is an elemental property of the wave, PWs interfere at the level of CW. We hypothesize that the asymmetry of brain-supplying arteries (that join to form CW) creates phase difference between the four PWs that interfere at the level of CW and reduce downstream cerebral pulsatility. To best of our knowledge, the data about the sequence of PWs' arrival into the cerebral circulation is lacking. Evident imperfect bilateral symmetry of the vessels results with different path length of brain-supplying arteries, hence, PWs should arrive into the head at different times. The probabilistic calculation shows that asynchronous arrival is more probable than synchronous. The importance of PWs for the cerebral circulation is highlighted by the observation that barotrauma protection mechanisms are more influenced by the crest of PW (pulse pressure) than by the mean arterial pressure. In addition, an increased arterial pulsatility is associated with several brain pathologies. We created simple computational models of four converging arteries and found that asynchronous arrival of the PWs results with lower maximum pressure, slower rate of pressure amplification and lower downstream pulsatility. In analogy, the asynchronous arrival of the pressure waves into the cerebral circulation should decrease blood flow pulsatility and lower transmission of kinetic energy on arterial wall. We conclude that asynchronous arrival of PWs into the cerebral circulation influences cerebral hemodynamics and represents a physiological necessity. PMID:26277658

  5. PULSATILE DRUG DELIVERY SYSTEM: A REVIEW

    Directory of Open Access Journals (Sweden)

    Jamil Faraz

    2012-07-01

    Full Text Available The purpose for this review on pulsatile drug delivery systems (PDDS is to compile the recent literatures with special focus on the different types and approaches involved in the development of the formulation. Pulsatile drug delivery system is the most interesting time and site-specific system. Diseases wherein PDDS are promising include asthma, peptic ulcer, cardiovascular diseases, arthritis,attention deficit syndrome in children, and hypercholesterolemia. PDDS can be classified into time controlled systems wherein the drug release is controlled primarily by the delivery system; stimuli induced PDDS in which release is controlled by the stimuli, like the pH or enzymes present in the Intestinal tract or enzymes present in the drug delivery system and externally regulated system where release is programmed by external stimuli like magnetism, ultrasound, electrical effect and irradiation. Marketed product like Pulsicap®, Ritalin® and Pulsys® are based on pulsatile release system. The aim of this review is to describe several types of drug delivery systems. This review also summarizes some current PDDS already available in the market. These systems are useful to several problems encountered during the development of a pharmaceutical dosage form.

  6. Detection and measurement of retinal blood vessel pulsatile motion

    Science.gov (United States)

    Xiao, Di; Frost, Shaun; Vignarajan, Janardhan; An, Dong; Tay-Kearney, Mei-Ling; Kanagasingam, Yogi

    2016-03-01

    Retinal photography is a non-invasive and well-accepted clinical diagnosis of ocular diseases. Qualitative and quantitative assessment of retinal images is crucial in ocular diseases related clinical application. Pulsatile properties caused by cardiac rhythm, such as spontaneous venous pulsation (SVP) and pulsatile motion of small arterioles, can be visualized by dynamic retinal imaging techniques and provide clinical significance. In this paper, we aim at vessel pulsatile motion detection and measurement. We proposed a novel approach for pulsatile motion measurement of retinal blood vessels by applying retinal image registration, blood vessel detection and blood vessel motion detection and measurement on infrared retinal image sequences. The performance of the proposed methods was evaluated on 8 image sequences with 240 images. A preliminary result has demonstrated the good performance of the method for blood vessel pulsatile motion observation and measurement.

  7. Pulsatile dynamics in the yeast proteome.

    Science.gov (United States)

    Dalal, Chiraj K; Cai, Long; Lin, Yihan; Rahbar, Kasra; Elowitz, Michael B

    2014-09-22

    The activation of transcription factors in response to environmental conditions is fundamental to cellular regulation. Recent work has revealed that some transcription factors are activated in stochastic pulses of nuclear localization, rather than at a constant level, even in a constant environment [1-12]. In such cases, signals control the mean activity of the transcription factor by modulating the frequency, duration, or amplitude of these pulses. Although specific pulsatile transcription factors have been identified in diverse cell types, it has remained unclear how prevalent pulsing is within the cell, how variable pulsing behaviors are between genes, and whether pulsing is specific to transcriptional regulators or is employed more broadly. To address these issues, we performed a proteome-wide movie-based screen to systematically identify localization-based pulsing behaviors in Saccharomyces cerevisiae. The screen examined all genes in a previously developed fluorescent protein fusion library of 4,159 strains [13] in multiple media conditions. This approach revealed stochastic pulsing in ten proteins, all transcription factors. In each case, pulse dynamics were heterogeneous and unsynchronized among cells in clonal populations. Pulsing is the only dynamic localization behavior that we observed, and it tends to occur in pairs of paralogous and redundant proteins. Taken together, these results suggest that pulsatile dynamics play a pervasive role in yeast and may be similarly prevalent in other eukaryotic species.

  8. Microprocessor-controlled pulsatile flow loop for hemodynamic studies.

    Science.gov (United States)

    Lynch, T G; Hobson, R W; Pawel, H E

    1986-03-01

    Validation of spectral analytic techniques in the clinical assessment and quantitation of vascular stenoses has been aided by use of in vitro flow loops. We have used a recently developed microprocessor-controlled pulsatile flow model to examine the influence of varying stenoses on Doppler-shifted peak systolic frequencies. A nonaxisymmetric, vertically oriented stenosis was produced by extrinsic compression of latex rubber tubing 12 mm in diameter, reducing the cross-sectional area (CSA) by 25, 40, 50, 60, 70, 85, and 97%. A rolling diaphragm pump, driven through a slider-crank mechanism by a microprocessor-controlled stepper motor, generated characteristic arterial pulse waves at a rate of 75 cycles per minute. Using an 8 MHz, continuous-wave, directional Doppler velocimeter, the Doppler-shifted frequencies were recorded at the stenosis. Four sets of observations were made at each of the stenoses, and the peak systolic frequency (PSF) was determined using a spectrum analyzer. The PSF in the absence of an obstructing stenosis was 2.56 +/- 0.03 (KHz +/- SEM). This increased significantly (P less than 0.05) to 4.80 +/- 0.09 when the CSA was reduced by 50%, to 5.90 +/- 0.37 when the CSA was reduced by 60% (P less than 0.05), to 8.40 +/- 0.10 when the CSA was reduced by 70% (P less than 0.05), and to 17.84 +/- 0.89 when the CSA was reduced by 85% (P less than 0.05). These data establish the utility of this pulsatile flow model, confirming the direct relationship between the Doppler-shifted PSF and the percentage reduction in CSA.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3951221

  9. Slip Effects on Pulsatile Flow of Blood through a Stenosed Arterial Segment under Periodic Body Acceleration

    OpenAIRE

    Sinha, A; Shit, G. C.; Kundu, P.K.

    2013-01-01

    A theoretical investigation concerning the influence of externally imposed periodic body acceleration on the flow of blood through a time-dependent stenosed arterial segment by taking into account the slip velocity at the wall of the artery has been carried out. A mathematical model is developed by treating blood as a non-Newtonian fluid obeying the Casson fluid model. The pulsatile flow is analyzed by considering a periodic pressure gradient and the inertial effects as negligibly small. A su...

  10. Decreased hypothalamic growth hormone-releasing hormone content and pituitary responsiveness in hypothyroidism.

    OpenAIRE

    Katakami, H; Downs, T R; Frohman, L A

    1986-01-01

    The effects of thyroidectomy (Tx) and thyroxine replacement (T4Rx) on pituitary growth hormone (GH) secretion and hypothalamic GH-releasing hormone (GRH) concentration were compared to define the mechanism of hypothyroid-associated GH deficiency. Thyroidectomized rats exhibited a complete loss of pulsatile GH secretion with extensive reduction in GRH responsiveness and pituitary GH content. Cultured pituitary cells from Tx rats exhibited reduced GRH sensitivity, maximal GH responsiveness, and...

  11. A hemodynamic evaluation of the Levitronix Pedivas centrifugal pump and Jostra Hl-20 roller pump under pulsatile and nonpulsatile perfusion in an infant CPB model.

    Science.gov (United States)

    Ressler, Noel; Rider, Alan R; Kunselman, Allen R; Richardson, J Scott; Dasse, Kurt A; Wang, Shigang; Undar, Akif

    2009-01-01

    The hemodynamic comparison of the Jostra HL-20 and the Levitronix PediVAS blood pumps is the focus this study, where pressure-flow waveforms and hemodynamic energy values are analyzed in the confines of a pediatric cardiopulmonary bypass circuit.The pseudo pediatric patient was perfused with flow rates between 500 and 900 ml/min (100 ml/min increments) under pulsatile and nonpulsatile mode. The Levitronix continuous flow pump utilized a customized controller to engage in pulsatile perfusion with equivalent pulse settings to the Jostra HL-20 roller pump. Hemodynamic measurements and waveforms were recorded at the precannula location, while the mean arterial pressure was maintained at 40 mm Hg for each test. Glycerin water was used as the blood analog circuit perfusate. At each flow rate 24 trials were conducted yielding a total of 120 experiments (n=60 pulsatile and n=60 nonpulsatile).Under nonpulsatile perfusion the Jostra roller pump produced small values for surplus hemodynamic energy (SHE) due to its inherent pulsatility, while the Levitronix produced values of essentially zero for SHE. When switching to pulsatile perfusion, the SHE levels for both the Jostra and Levitronix pump made considerable increases. In comparing the two pumps under pulsatile perfusion, the Levitronix PediVAS produced significantly more surplus and total hemodynamic energy than did the Jostra roller pump each pump flow rate.The study suggests that the Levitronix PediVAS centrifugal pump has the capability of achieving quality pulsatile waveforms and delivering more SHE to the pseudo patient than the Jostra HL-20 roller pump. Further studies are warranted to investigate the Levitronix under bovine blood studies and with various pulsatile settings.

  12. ORAL MULTIPARTICULATE PULSATILE DRUG DELIVERY SYSTEMS: A REVIEW

    OpenAIRE

    Shaji Jessy; Shinde Amol B

    2011-01-01

    Pulsatile drug delivery aims to release drugs in a planned pattern i.e. at appropriate time and/or at a suitable site of action. Pharmaceutical invention and research are increasingly focusing on delivery systems which enhance desirable therapeutic objectives while minimising side effects. However, in recent pharmaceutical applications involving pulsatile delivery, multiparticulate dosage forms are gaining much favour over single-unit dosage forms because of their potential benefits like pred...

  13. Mathematical modeling of fluid dynamics in pulsatile cardiopulmonary bypass.

    Science.gov (United States)

    Pennati, Giancarlo; Fiore, Gianfranco B; Laganà, Katia; Fumero, Roberto

    2004-02-01

    The design criteria of an extracorporeal circuit suitable for pulsatile flow are quite different and more entangled than for steady flow. The time and costs of the design process could be reduced if mutual influences between the pulsatile pump and other extracorporeal devices were considered without experimental trial-and-error activities. With this in mind, we have developed a new lumped-parameter mathematical model of the hydraulic behavior of the arterial side of an extracorporeal circuit under pulsatile flow conditions. Generally, components feature a resistant-inertant-compliant behavior and the most relevant nonlinearities are accounted for. Parameter values were derived either by experimental tests or by analytical analysis. The pulsatile pump is modeled as a pure pulsatile flow generator. Model predictions were compared with flow rate and pressure tracings measured during hydraulic tests on two different circuits at various flow rates and pulse frequencies. The normalized root mean square error did not exceed 24% and the model accurately describes the changes that occur in the basic features of the pressure and flow wave propagating from the pulsatile pump to the arterial cannula. PMID:14961960

  14. Optimum Heart Rate to Minimize Pulsatile External Cardiac Power

    Science.gov (United States)

    Pahlevan, Niema; Gharib, Morteza

    2011-11-01

    The workload on the left ventricle is composed of steady and pulsatile components. Clinical investigations have confirmed that an abnormal pulsatile load plays an important role in the pathogenesis of left ventricular hypertrophy (LVH) and progression of LVH to congestive heart failure (CHF). The pulsatile load is the result of the complex dynamics of wave propagation and reflection in the compliant arterial vasculature. We hypothesize that aortic waves can be optimized to reduce the left ventricular (LV) pulsatile load. We used an in-vitro experimental approach to investigate our hypothesis. A unique hydraulic model was used for in-vitro experiments. This model has physical and dynamical properties similar to the heart-aorta system. Different compliant models of the artificial aorta were used to test the hypothesis under various aortic rigidities. Our results indicate that: i) there is an optimum heart rate that minimizes LV pulsatile power (this is in agreement with our previous computational study); ii) introducing an extra reflection site at the specific location along the aorta creates constructive wave conditions that reduce the LV pulsatile power.

  15. Optimization studies on compression coated floating-pulsatile drug delivery of bisoprolol.

    Science.gov (United States)

    Jagdale, Swati C; Bari, Nilesh A; Kuchekar, Bhanudas S; Chabukswar, Aniruddha R

    2013-01-01

    The purpose of the present work was to design and optimize compression coated floating pulsatile drug delivery systems of bisoprolol. Floating pulsatile concept was applied to increase the gastric residence of the dosage form having lag phase followed by a burst release. The prepared system consisted of two parts: a core tablet containing the active ingredient and an erodible outer shell with gas generating agent. The rapid release core tablet (RRCT) was prepared by using superdisintegrants with active ingredient. Press coating of optimized RRCT was done by polymer. A 3² full factorial design was used for optimization. The amount of Polyox WSR205 and Polyox WSR N12K was selected as independent variables. Lag period, drug release, and swelling index were selected as dependent variables. Floating pulsatile release formulation (FPRT) F13 at level 0 (55 mg) for Polyox WSR205 and level +1 (65 mg) for Polyox WSR N12K showed lag time of 4 h with >90% drug release. The data were statistically analyzed using ANOVA, and P < 0.05 was statistically significant. Release kinetics of the optimized formulation best fitted the zero order model. In vivo study confirms burst effect at 4 h in indicating the optimization of the dosage form. PMID:24367788

  16. Optimization Studies on Compression Coated Floating-Pulsatile Drug Delivery of Bisoprolol

    Directory of Open Access Journals (Sweden)

    Swati C. Jagdale

    2013-01-01

    Full Text Available The purpose of the present work was to design and optimize compression coated floating pulsatile drug delivery systems of bisoprolol. Floating pulsatile concept was applied to increase the gastric residence of the dosage form having lag phase followed by a burst release. The prepared system consisted of two parts: a core tablet containing the active ingredient and an erodible outer shell with gas generating agent. The rapid release core tablet (RRCT was prepared by using superdisintegrants with active ingredient. Press coating of optimized RRCT was done by polymer. A 32 full factorial design was used for optimization. The amount of Polyox WSR205 and Polyox WSR N12K was selected as independent variables. Lag period, drug release, and swelling index were selected as dependent variables. Floating pulsatile release formulation (FPRT F13 at level 0 (55 mg for Polyox WSR205 and level +1 (65 mg for Polyox WSR N12K showed lag time of 4 h with >90% drug release. The data were statistically analyzed using ANOVA, and P<0.05 was statistically significant. Release kinetics of the optimized formulation best fitted the zero order model. In vivo study confirms burst effect at 4 h in indicating the optimization of the dosage form.

  17. 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

  18. A new method of providing pulsatile flow in a centrifugal pump: assessment of pulsatility using a mock circulatory system.

    Science.gov (United States)

    Herreros, Jesús; Berjano, Enrique J; Sales-Nebot, Laura; Más, Pedro; Calvo, Irene; Mastrobuoni, Stefano; Mercé, Salvador

    2008-06-01

    Previous studies have demonstrated the potential advantages of pulsatile flow as compared with continuous flow. However, to date, physiologic pumps have been technically complex and their application has therefore remained in the experimental field. We have developed a new type of centrifugal pump, which can provide pulsatile as well as continuous flow. The inner wall of a centrifugal pump is pulsed by means of a flexible membrane, which can be accurately controlled by means of either a hydraulic or pneumatic driver. The aim of this study was to assess the hydraulic behavior of the new pump in terms of surplus hemodynamic energy (SHE). We conducted experiments using a mock circulatory system including a membrane oxygenator. No differences were found in the pressure-flow characteristics between the new pump and a conventional centrifugal pump, suggesting that the inclusion of the flexible membrane does not alter hydraulic performance. The value of SHE rose when systolic volume was increased. However, SHE dropped when the percentage of ejection time was reduced and also when the continuous flow (programmed by the centrifugal console) increased. Mean flow matched well with the continuous flow set by the centrifugal console, that is, the pulsatile component of the flow was exclusively controlled by the pulsatile console, and was therefore independent of the continuous flow programmed by the centrifugal console. The pulsatility of the new pump was approximately 25% of that created with a truly pulsatile pump.

  19. Evaluating microcirculation by pulsatile laser Doppler signal

    Science.gov (United States)

    Chao, P. T.; Jan, M. Y.; Hsiu, H.; Hsu, T. L.; Wang, W. K.; Wang, Y. Y. Lin

    2006-02-01

    Laser Doppler flowmetry (LDF) is a popular method for monitoring the microcirculation, but it does not provide absolute measurements. Instead, the mean flux response or energy distribution in the frequency domain is generally compared before and after stimulus. Using the heartbeat as a trigger, we investigated whether the relation between pressure and flux can be used to discriminate different microcirculatory conditions. We propose the following three pulsatile indices for evaluating the microcirculation condition from the normalized pressure and flux segment with a synchronized-averaging method: peak delay time (PDT), pressure rise time and flux rise time (FRT). The abdominal aortic blood pressure and renal cortex flux (RCF) signals were measured in spontaneously hypertensive rats (SHR) and Wistar Kyoto rats (WKY). The mean value of the RCF did not differ between SHR and WKY. However, the PDT was longer in SHR (87.14 ± 5.54 ms, mean ± SD) than in WKY (76.92 ± 2.62 ms; p discriminate RCF signals that cannot be discriminated using traditional methods.

  20. Pulsatile blood flow in Abdominal Aortic Aneurysms

    Science.gov (United States)

    Salsac, Anne-Virginie; Lasheras, Juan C.; Singel, Soeren; Varga, Chris

    2001-11-01

    We discuss the results of combined in-vitro laboratory measurements and clinical observations aimed at determining the effect that the unsteady wall shear stresses and the pressure may have on the growth and eventual rupturing of an Abdominal Aortic Aneurysm (AAA), a permanent bulging-like dilatation occurring near the aortic bifurcation. In recent years, new non-invasive techniques, such as stenting, have been used to treat these AAAs. However, the development of these implants, aimed at stopping the growth of the aneurysm, has been hampered by the lack of understanding of the effect that the hemodynamic forces have on the growth mechanism. Since current in-vivo measuring techniques lack the precision and the necessary resolution, we have performed measurements of the pressure and shear stresses in laboratory models. The models of the AAA were obtained from high resolution three-dimensional CAT/SCANS performed in patients at early stages of the disease. Preliminary DPIV measurements show that the pulsatile blood flow discharging into the cavity of the aneurysm leads to large spikes of pressure and wall shear stresses near and around its distal end, indicating a possible correlation between the regions of high wall shear stresses and the observed location of the growth of the aneurysm.

  1. Pulsatile instability in rapid directional solidification - Strongly-nonlinear analysis

    Science.gov (United States)

    Merchant, G. J.; Braun, R. J.; Brattkus, K.; Davis, S. H.

    1992-01-01

    In the rapid directional solidification of a dilute binary alloy, analysis reveals that, in addition to the cellular mode of Mullins and Sekerka (1964), there is an oscillatory instability. For the model analyzed by Merchant and Davis (1990), the preferred wavenumber is zero; the mode is one of pulsation. Two strongly nonlinear analyses are performed that describe this pulsatile mode. In the first case, nonequilibrium effects that alter solute rejection at the interface are taken asymptotically small. A nonlinear oscillator equation governs the position of the solid-liquid interface at leading order, and amplitude and phase evolution equations are derived for the uniformly pulsating interface. The analysis provides a uniform description of both subcritical and supercritical bifurcation and the transition between the two. In the second case, nonequilibrium effects that alter solute rejection are taken asymptotically large, and a different nonlinear oscillator equation governs the location of the interface to leading order. A similar analysis allows for the derivation of an amplitude evolution equation for the uniformly pulsating interface. In this case, the bifurcation is always supercritical. The results are used to make predictions about the characteristics of solute bands that would be frozen into the solid.

  2. Growth Hormone

    Science.gov (United States)

    ... page: Was this page helpful? Also known as: GH; Human Growth Hormone; HGH; Somatotropin; Growth Hormone Stimulation Test; Growth Hormone ... I should know? How is it used? Growth hormone (GH) testing is primarily used to identify growth hormone ...

  3. Rotary pumps and diminished pulsatility: do we need a pulse?

    Science.gov (United States)

    Soucy, Kevin G; Koenig, Steven C; Giridharan, Guruprasad A; Sobieski, Michael A; Slaughter, Mark S

    2013-01-01

    Ventricular assist devices (VADs) have been successfully used as a bridge to heart transplant and destination therapy (DT) for congestive heart failure (HF) patients. Recently, continuous flow VAD (CVAD) has emerged as an attractive clinical option for long-term mechanical support of HF patients, with bridge-to-transplant outcomes comparable with pulsatile flow VAD (PVAD). Continuous flow VADs are smaller, more reliable, and less complex than the first-generation PVAD. Despite the widespread clinical use, CVAD support has been associated with gastrointestinal bleeding, hemorrhagic strokes, and aortic valve insufficiency. Speculation that diminished arterial pressure pulsatility associated with continuous flow devices may be contributing to these complications has sparked much debate over CVAD support. Studies comparing pulsatile flow and continuous flow (CF) support have presented conflicting findings, and the relevance to CVAD as DT is uncertain due to variations in device operation, support duration, and the criteria used to quantify pulsatility. Currently, there is interest in developing control algorithms for CVAD to increase the delivered pulsatility as a strategy to mitigate adverse event risks associated with CVAD therapy. There may also be the added benefit of specific control strategies for managing CVAD therapy, potentially improving the rate of myocardial recovery and successful weaning of mechanical circulatory support. PMID:23820272

  4. Secreción pulsátil diurna y nocturna de hormona del crecimiento en ovejas prepúberes con y sin restricción alimentaria Diurnal and nocturnal pulsatile growth hormone secretion in ewe lambs with and without food restriction

    Directory of Open Access Journals (Sweden)

    S.E. RECABARREN

    1998-01-01

    Full Text Available Estudios sobre las características de la secreción pulsátil ultradiana de GH en la borrega en crecimiento son escasos, y en particular, respecto de posibles diferencias entre la secreción diurna y nocturna, y si la restricción alimentaria es capaz de modificar los patrones de secreción pulsátil. En el presente estudio se comparó la frecuencia y la amplitud de pulsos de hormona del crecimiento (GH diurnos y nocturnos durante el desarrollo prepuberal de borregas Suffolk con y sin restricción alimentaria Para ello, se realizaron estudios de pulsatilidad de GH a las 20, 26 y 30 semanas de edad, en borregas sometidas a restricción alimentaria (GR por 5, 11 y 15 semanas. Borregas de la misma edad sirvieron de control (GC. El estudio de pulsatilidad de GH se repitió en las borregas GR luego de 2 semanas de realimentación. El estudio de pulsatilidad de GH consistió en la colección de muestras de sangre desde la vena yugular cada 10 min por seis horas desde las 08:00 h para la determinación de la pulsatilidad diurna y desde las 20:00 h para la pulsatilidad nocturna. La definición de las características de la secreción pulsátil de GH se obtuvo con el programa CLUSTER. La concentración promedio (ng/ml, la amplitud de pulsos (ng/ml y la frecuencia de pulsos (nº de pulsos/6h diurna fue similar a la nocturna tanto en las borregas GC como en las borregas GR, en las 3 edades estudiadas. Aunque los parámetros de secreción diurnos y nocturnos fueron iguales entre sí en cada grupo, la concentración promedio diurna y nocturna del grupo GR fue siempre mayor (p The aim of the study was to characterise and to compare diurnal (D and nocturnal (N GH secretion in normal growing and in food-restricted Suffolk ewe lambs. Pulsatile GH secretion was studied in 6, 20, 26 and 30 week-old lambs (group GC and in six other lambs of the same age, after 5, 11 and 15 weeks of food restriction (group GR. At the end of the food restriction period, GR lambs

  5. 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.

  6. 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.)

  7. Case of a non-pulsatile groin swelling.

    Science.gov (United States)

    Razif, M A Mohamed; Rajasingam, V; Abdullah, B J J

    2002-12-01

    We report a case of a non-pulsatile groin swelling in a 38 years old male drug addict without the typical clinical signs of an aneurysm. Ultrasound revealed a left femoral artery pseudo-aneurysm. He was surgically treated and the vessels were ligated without revascularisation.

  8. Augmentation of abdominal organ perfusion during cardiopulmonary bypass with a novel intra-aortic pulsatile catheter pump

    NARCIS (Netherlands)

    Gu, YJ; De Kroon, T; Elstrodt, JM; van Oeveren, W; Boonstra, PW; Rakhorst, G

    2005-01-01

    Background: Current pulsatile pumps for cardiopulmonary bypass (CPB) are far from satisfactory because of the poor pulsatility. This study was undertaken to examine the efficiency of a novel pulsatile catheter pump on pulsatility and its effect on abdominal organ perfusion during CPB. Methods: Twelv

  9. Automatic segmentation and co-registration of gated CT angiography datasets: measuring abdominal aortic pulsatility

    Science.gov (United States)

    Wentz, Robert; Manduca, Armando; Fletcher, J. G.; Siddiki, Hassan; Shields, Raymond C.; Vrtiska, Terri; Spencer, Garrett; Primak, Andrew N.; Zhang, Jie; Nielson, Theresa; McCollough, Cynthia; Yu, Lifeng

    2007-03-01

    Purpose: To develop robust, novel segmentation and co-registration software to analyze temporally overlapping CT angiography datasets, with an aim to permit automated measurement of regional aortic pulsatility in patients with abdominal aortic aneurysms. Methods: We perform retrospective gated CT angiography in patients with abdominal aortic aneurysms. Multiple, temporally overlapping, time-resolved CT angiography datasets are reconstructed over the cardiac cycle, with aortic segmentation performed using a priori anatomic assumptions for the aorta and heart. Visual quality assessment is performed following automatic segmentation with manual editing. Following subsequent centerline generation, centerlines are cross-registered across phases, with internal validation of co-registration performed by examining registration at the regions of greatest diameter change (i.e. when the second derivative is maximal). Results: We have performed gated CT angiography in 60 patients. Automatic seed placement is successful in 79% of datasets, requiring either no editing (70%) or minimal editing (less than 1 minute; 12%). Causes of error include segmentation into adjacent, high-attenuating, nonvascular tissues; small segmentation errors associated with calcified plaque; and segmentation of non-renal, small paralumbar arteries. Internal validation of cross-registration demonstrates appropriate registration in our patient population. In general, we observed that aortic pulsatility can vary along the course of the abdominal aorta. Pulsation can also vary within an aneurysm as well as between aneurysms, but the clinical significance of these findings remain unknown. Conclusions: Visualization of large vessel pulsatility is possible using ECG-gated CT angiography, partial scan reconstruction, automatic segmentation, centerline generation, and coregistration of temporally resolved datasets.

  10. Frequency-Dependent Neural Activity in Patients with Unilateral Vascular Pulsatile Tinnitus

    Directory of Open Access Journals (Sweden)

    Han Lv

    2016-01-01

    Full Text Available Previous resting-state functional magnetic resonance imaging (rs-fMRI studies have shown that neurological changes are important findings in vascular pulsatile tinnitus (PT patients. Here, we utilized rs-fMRI to measure the amplitude of low-frequency fluctuations (ALFF in forty patients with unilateral PT and forty age-, gender-, and education-matched normal control subjects. Two different frequency bands (slow-4, 0.027–0.073 Hz, and slow-5, 0.010–0.027 Hz, which are more sensitive to subcortical and cortical neurological signal changes, resp. were analyzed to examine the intrinsic brain activity in detail. Compared to controls, PT patients had increased ALFF values mainly in the PCu, bilateral IPL (inferior parietal lobule, left IFG (inferior frontal gyrus, and right IFG/anterior insula and decreased ALFF values in the multiple occipital areas including bilateral middle-inferior occipital lobe. For the differences of the two frequency bands, widespread ALFF differences were observed. The ALFF abnormalities in aMPFC/ACC, PCu, right IPL, and some regions of occipital and parietal cortices were greater in the slow-5 band compared to the slow-4 band. Additionally, the THI score of PT patients was positively correlated with changes in slow-5 and slow-4 band in PCu. Pulsatile tinnitus is a disease affecting the neurological activities of multiple brain regions. Slow-5 band is more sensitive in detecting the alternations. Our results also indicated the importance of pathophysiological investigations in patients with pulsatile tinnitus in the future.

  11. Frequency-Dependent Neural Activity in Patients with Unilateral Vascular Pulsatile Tinnitus.

    Science.gov (United States)

    Lv, Han; Zhao, Pengfei; Liu, Zhaohui; Wang, Guopeng; Zeng, Rong; Yan, Fei; Dong, Cheng; Zhang, Ling; Li, Rui; Wang, Peng; Li, Ting; Gong, Shusheng; Wang, Zhenchang

    2016-01-01

    Previous resting-state functional magnetic resonance imaging (rs-fMRI) studies have shown that neurological changes are important findings in vascular pulsatile tinnitus (PT) patients. Here, we utilized rs-fMRI to measure the amplitude of low-frequency fluctuations (ALFF) in forty patients with unilateral PT and forty age-, gender-, and education-matched normal control subjects. Two different frequency bands (slow-4, 0.027-0.073 Hz, and slow-5, 0.010-0.027 Hz, which are more sensitive to subcortical and cortical neurological signal changes, resp.) were analyzed to examine the intrinsic brain activity in detail. Compared to controls, PT patients had increased ALFF values mainly in the PCu, bilateral IPL (inferior parietal lobule), left IFG (inferior frontal gyrus), and right IFG/anterior insula and decreased ALFF values in the multiple occipital areas including bilateral middle-inferior occipital lobe. For the differences of the two frequency bands, widespread ALFF differences were observed. The ALFF abnormalities in aMPFC/ACC, PCu, right IPL, and some regions of occipital and parietal cortices were greater in the slow-5 band compared to the slow-4 band. Additionally, the THI score of PT patients was positively correlated with changes in slow-5 and slow-4 band in PCu. Pulsatile tinnitus is a disease affecting the neurological activities of multiple brain regions. Slow-5 band is more sensitive in detecting the alternations. Our results also indicated the importance of pathophysiological investigations in patients with pulsatile tinnitus in the future. PMID:27413554

  12. Frequency-Dependent Neural Activity in Patients with Unilateral Vascular Pulsatile Tinnitus

    Science.gov (United States)

    Lv, Han; Zhao, Pengfei; Liu, Zhaohui; Wang, Guopeng; Zeng, Rong; Yan, Fei; Dong, Cheng; Zhang, Ling; Li, Rui; Wang, Peng; Li, Ting

    2016-01-01

    Previous resting-state functional magnetic resonance imaging (rs-fMRI) studies have shown that neurological changes are important findings in vascular pulsatile tinnitus (PT) patients. Here, we utilized rs-fMRI to measure the amplitude of low-frequency fluctuations (ALFF) in forty patients with unilateral PT and forty age-, gender-, and education-matched normal control subjects. Two different frequency bands (slow-4, 0.027–0.073 Hz, and slow-5, 0.010–0.027 Hz, which are more sensitive to subcortical and cortical neurological signal changes, resp.) were analyzed to examine the intrinsic brain activity in detail. Compared to controls, PT patients had increased ALFF values mainly in the PCu, bilateral IPL (inferior parietal lobule), left IFG (inferior frontal gyrus), and right IFG/anterior insula and decreased ALFF values in the multiple occipital areas including bilateral middle-inferior occipital lobe. For the differences of the two frequency bands, widespread ALFF differences were observed. The ALFF abnormalities in aMPFC/ACC, PCu, right IPL, and some regions of occipital and parietal cortices were greater in the slow-5 band compared to the slow-4 band. Additionally, the THI score of PT patients was positively correlated with changes in slow-5 and slow-4 band in PCu. Pulsatile tinnitus is a disease affecting the neurological activities of multiple brain regions. Slow-5 band is more sensitive in detecting the alternations. Our results also indicated the importance of pathophysiological investigations in patients with pulsatile tinnitus in the future. PMID:27413554

  13. A Meta-Analysis of Renal Function After Adult Cardiac Surgery With Pulsatile Perfusion.

    Science.gov (United States)

    Nam, Myung Ji; Lim, Choon Hak; Kim, Hyun-Jung; Kim, Yong Hwi; Choi, Hyuk; Son, Ho Sung; Lim, Hae Ja; Sun, Kyung

    2015-09-01

    The aim of this meta-analysis was to determine whether pulsatile perfusion during cardiac surgery has a lesser effect on renal dysfunction than nonpulsatile perfusion after cardiac surgery in randomized controlled trials. MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials were used to identify available articles published before April 25, 2014. Meta-analysis was conducted to determine the effects of pulsatile perfusion on postoperative renal functions, as determined by creatinine clearance (CrCl), serum creatinine (Cr), urinary neutrophil gelatinase-associated lipocalin (NGAL), and the incidences of acute renal insufficiency (ARI) and acute renal failure (ARF). Nine studies involving 674 patients that received pulsatile perfusion and 698 patients that received nonpulsatile perfusion during cardiopulmonary bypass (CPB) were considered in the meta-analysis. Stratified analysis was performed according to effective pulsatility or unclear pulsatility of the pulsatile perfusion method in the presence of heterogeneity. NGAL levels were not significantly different between the pulsatile and nonpulsatile groups. However, patients in the pulsatile group had a significantly higher CrCl and lower Cr levels when the analysis was restricted to studies on effective pulsatile flow (P < 0.00001, respectively). The incidence of ARI was significantly lower in the pulsatile group (P < 0.00001), but incidences of ARF were similar. In conclusion, the meta-analysis suggests that the use of pulsatile flow during CPB results in better postoperative renal function.

  14. A COMPREHENSIVE REVIEW OF PULSATILE DRUG DELIVERY SYSTEMS

    Directory of Open Access Journals (Sweden)

    Rompicharla Bhargavi

    2012-03-01

    Full Text Available Pulsatile drug delivery systems are gaining popularity in the field of pharmaceutical formulation, research and development. The prime advantage in this drug delivery is that the drug is released as per the pathophysiological need of the disease. As a result the change of development of drug resistance which is seen in conventional and sustained released formulations can be reduced. This therapy is mainly applicable where sustained action is not required and the drugs are toxic. Basic point of development of this formulation is to find out the circadian rhythms that is a suitable indicator that will trigger the release of drug from the device. Clock genes are the genes that control the circadian rhythms in human physiology. Pulsatile drug delivery systems are promising incase of asthma, cardiovascular diseases, peptic ulcers, arthritis, and hypercholesterolemic conditions.

  15. The dynamics of pulsatile flow in distensible model arteries.

    Science.gov (United States)

    Liepsch, D W; Zimmer, R

    1995-12-01

    Deposits and blockages are often found in the carotid, coronary, renal and femoral arteries. This paper deals with laser-Doppler velocity measurements in models of bifurcations of the human femoral arteries. Several models were prepared for the studies: a simplified 35 degrees glass model, two elastic-silicone-rubber models with a wall thickness of 1 mm and 2 mm, and true-to-scale rigid and elastic models. These measurements give a clearer picture of how hemodynamics influences the formation of atherosclerotic plaques where there is a hardening of the arterial walls and a loss of elasticity. In addition to the effects of elasticity, the influence of the flow's pulsatility were studied. The measurements were done in steady and pulsatile flow. From the velocity measurements the shear stresses were calculated.

  16. Influence of vascular function and pulsatile hemodynamics on cardiac function.

    Science.gov (United States)

    Bell, Vanessa; Mitchell, Gary F

    2015-09-01

    Interactions between cardiac and vascular structure and function normally are optimized to ensure delivery of cardiac output with modest pulsatile hemodynamic overhead. Aortic stiffening with age or disease impairs optimal ventricular-vascular coupling, increases pulsatile load, and contributes to left ventricular (LV) hypertrophy, reduced systolic function, and impaired diastolic relaxation. Aortic pulse pressure and timing of peak systolic pressure are well-known measures of hemodynamic ventricular-vascular interaction. Recent work has elucidated the importance of direct, mechanical coupling between the aorta and the heart. LV systolic contraction results in displacement of aortic and mitral annuli, thereby producing longitudinal stretch in the ascending aorta and left atrium, respectively. Force associated with longitudinal stretch increases systolic load on the LV. However, the resulting energy stored in the elastic elements of the proximal aorta during systole facilitates early diastolic LV recoil and rapid filling. This review discusses current views on hemodynamics and mechanics of ventricular-vascular coupling. PMID:26164466

  17. Numerical computation of pulsatile flow through a locally constricted channel

    Science.gov (United States)

    Bandyopadhyay, S.; Layek, G. C.

    2011-01-01

    This paper deals with the numerical solution of a pulsatile laminar flow through a locally constricted channel. A finite difference technique has been employed to solve the governing equations. The effects of the flow parameters such as Reynolds number, flow pulsation in terms of Strouhal number, constriction height and length on the flow behaviour have been studied. It is found that the peak value of the wall shear stress has significantly changed with the variation of Reynolds numbers and constriction heights. It is also noted that the Strouhal number and constriction length have little effect on the peak value of the wall shear stress. The flow computation reveals that the peak value of the wall shear stress at maximum flow rate time in pulsatile flow situation is much larger than that due to steady flow. The constriction and the flow pulsation produce flow disturbances at the vicinity of the constriction of the channel in the downstream direction.

  18. CFD modeling of pulsatile hemodynamics in the total cavopulmonary connection

    Science.gov (United States)

    Zobaer, S. M. Tareq; Hasan, A. B. M. Toufique

    2016-07-01

    Total cavopulmonary connection is a blood flow pathway which is created surgically by an operation known as Fontan procedure, performed on children with single ventricle heart defects. Recent studies have shown that the hemodynamics in the connection can be strongly influenced by the presence of pulsatile flow. The aim of this paper is model the pulsatile flow patterns, and to calculate the vorticity field and power losses in an idealized 1.5D offset model of Total Cavopulmonary Connection. A three-dimensional polyhedral mesh was constructed for the numerical simulation. The rheological properties of blood were considered as Newtonian, and flow in the connection was assumed to be laminar. The results demonstrated complex flow patterns in the connection. The outcomes of the simulation showed reasonable agreement with the results available in the literature for a similar model.

  19. Arterial Stiffness, Central Pulsatile Hemodynamic Load, and Orthostatic Hypotension.

    Science.gov (United States)

    Liu, Kai; Wang, Si; Wan, Shixi; Zhou, Yufei; Pan, Pei; Wen, Bo; Zhang, Xin; Liao, Hang; Shi, Di; Shi, Rufeng; Chen, Xiaoping; Jangala, Tulasiram

    2016-07-01

    The association between central pulsatile hemodynamic load, arterial stiffness, and orthostatic hypotension (OH) is unclear. The authors recruited 1099 participants from the community. Questionnaire, physical examination, and laboratory tests were performed. To assess the correlation between central pulsatile hemodynamic load, arterial stiffness, and OH, multiple logistic regression analysis was performed, and the discriminatory power was assessed by the area under the receiver operating curve. The prevalence of OH in this population was 5.6%. After adjusting for potential confounders, brachial-ankle pulse wave velocity (BaPWV) was significantly and positively correlated with OH in both the hypertension and nonhypertension groups (all Ppower than CSBP in both subgroups. BaPWV appears to be a better indicator of OH than CSBP in routine clinical practice. PMID:26543017

  20. INTERVENTIONAI DIAGNOSIS AND TREATMENT OF VASCULOGENEIC PULSATILE TINNITUS

    Institute of Scientific and Technical Information of China (English)

    LI Baomin; CAO Xiangyu; LIU Xinfeng; LI Sheng; WANG Jun; LIANG Yongping; GE Aili; ZHANG Alan; FENG Huimin

    2014-01-01

    Objective To retrospectively study clinical features and diagnostic imaging of vasculogeneic pulsatile tin-nitus, and the feasibility and efficacy of transvascular interventional treatment for this condition. Methods Data from 82 cases of arterial or venous pulsatile tinnitus were reviewed. DSA characteristics and possible pathophysiological mechanisms of pulsatile tinnitus in these cases were studied. Diagnoses in this group in-cluded intracranial arterovenous fistula (AVF) (n=3), spontaneous skull base dural AVF (n=16), traumatic ca-rotid-cavernous sinus fistula (n=5), subclavian artery stenosis (n=2), internal carotid artery stenosis (n=3), in-tracranial arterial stenosis (n=1), kinked and/or elongated vertebrobasilar artery (n=2), venous sinus divertic-ulum (n=2), venous sinus stenosis on the dominant drainage side (n=46) and occipital sinus stenosis (n=2). Treatments included embolization and stenting using coils, NBCA glue, Balt balloons, self-expansion stents and intracranial micro-stents via either the femoral artery or femoral vein. Results Procedures were suc-cessful in all cases with no surgery-related complications. Tinnitus disappeared within 2 days after the pro-cedure in all cases. Follow up duration was 5-36 months. Recurrence occurred in 4 cases of arterial tinnitus within 3 months following the initial procedure, which improved after revision embolization or symptom management. There was no recurrence in venous tinnitus cases following stent plastic or stent-coiling embo-lization treatments. Conclusions Endovascular intervention provides a new approach to the diagnosis and treatment of intractable pulsatile tinnitus. It is also effective in differentiating and studying other types of tinnitus.

  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. Non-invasive monitoring of reproduction in male lesser mouse deer (Tragulus javanicus): Analyzing hormon testosterone and its metabolites in faeces using HPLC and enzyme immunoassay

    International Nuclear Information System (INIS)

    The lesser mouse deer (Tragulus javanicus, family Tragulidae) is a ruminant that inhabits the tropical rain forest of the South East Asia (Medway, 1969). The animal is regarded as the smallest ruminant and has been proposed to be a model in the biomedical and ruminant research (Kudo et al., 1997). On the other hand, this animal is an interesting collection in the zoo and other conservation areas for the purpose of education and tourism, showed larger proportion of carcasses and therefore suitable as an alternative meat source. Recently, the population of the lesser mouse deer is threatened by illegal hunting and habitat destruction. Therefore, conservation and management of the animal is becoming important. One success key on the conservation and breeding strategy of wild animal include the management and knowledge of the reproductive system. Only limited information are available on the reproductive physiology of the lesser mouse deer although several studies have been undertaken on the reproductive system of the male and female lesser mouse deer (Haron et al., 2000; Kimura et al., 2004; Agungpriyono et al., 2005). Previous studies on the male lesser mouse deer revealed the sperm quality (Haron et al., 2000; Agungpriyono et al., 2005), spermatozoa morphology and histochemical properties (Agungpriyono et al., 2005). Furthermore, it has also been reported that intermandibular scent gland may play important roles in the communication and sexual behaviour of mouse deer (Ralls et al., 1975; Agungpriyono et al., 2006). Attempts at natural breeding of lesser mouse deer in captive are still unsuccessful. This may be due to the lack of information about animal reproduction, both male and female of lesser mouse deer, the unstable behaviour, aggressiveness, stress and less attraction and ability to mount during the captive breeding (Haron et al 2000, Kudo et al 1997). Testosterone is the main hormone concerning the male reproductive biology that it indicates the age of

  3. Visualization of pulsatile flow for magnetic nanoparticle based therapies

    Science.gov (United States)

    Wentzel, Andrew; Yecko, Philip

    2015-11-01

    Pulsatile flow of blood through branched, curved, stenosed, dilated or otherwise perturbed vessels is more complex than flow through a straight, uniform and rigid tube. In some magnetic hyperthermia and magnetic chemo-therapies, localized regions of magnetic nanoparticle laden fluid are deliberately formed in blood vessels and held in place by magnetic fields. The effect of localized magnetic fluid regions on blood flow and the effect of the pulsatile blood flow on such magnetic fluid regions are poorly understood and difficult to examine in vivo or by numerical simulation. We present a laboratory model that facilitates both dye tracer and particle imaging velocimetry (PIV) studies of pulsatile flow of water through semi-flexible tubes in the presence of localized magnetic fluid regions. Results on the visualization of flows over a range of Reynolds and Womersley numbers and for several different (water-based) ferrofluids are compared for straight and curved vessels and for different magnetic localization strategies. These results can guide the design of improved magnetic cancer therapies. Support from the William H. Sandholm Program of Cooper Union's Kanbar Center for Biomedical Engineering is gratefully acknowledged.

  4. Pulsatile drug delivery systems: An approach for controlled drug delivery

    Directory of Open Access Journals (Sweden)

    Arora Shweta

    2006-01-01

    Full Text Available Pulsatile systems are gaining a lot of interest as they deliver the drug at the right site of action at the right time and in the right amount, thus providing spatial and temporal delivery and increasing patient compliance. These systems are designed according to the circadian rhythm of the body. The principle rationale for the use of pulsatile release is for the drugs where a constant drug release, i.e., a zero-order release is not desired. The release of the drug as a pulse after a lag time has to be designed in such a way that a complete and rapid drug release follows the lag time. Various systems like capsular systems, osmotic systems, single- and multiple-unit systems based on the use of soluble or erodible polymer coating and use of rupturable membranes have been dealt with in the article. It summarizes the latest technological developments, formulation parameters, and release profiles of these systems. Products available as once-a-daily formulation based on Pulsatile release like Pulsincap ®, Ritalin ®, and Pulsys ® are also covered in the review. These systems are beneficial for the drugs having chronopharmacological behaviour where night time dosing is required and for the drugs having high first-pass effect and having specific site of absorption in GIT. Drugs used in asthmatic patients and patients suffering from rheumatoid arthritis are also discussed along with many other examples.

  5. 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.

  6. Specificity of synergistic coronary flow enhancement by adenosine and pulsatile perfusion in the dog.

    Science.gov (United States)

    Pagliaro, P; Senzaki, H; Paolocci, N; Isoda, T; Sunagawa, G; Recchia, F A; Kass, D A

    1999-10-01

    1. Coronary flow elevation from enhanced perfusion pulsatility is synergistically amplified by adenosine. This study determined the specificity of this interaction and its potential mechanisms. 2. Mean and phasic coronary flow responses to increasing pulsatile perfusion were assessed in anaesthetized dogs, with the anterior descending coronary artery servoperfused to regulate real-time physiological flow pulsatility at constant mean pressure. Pulsatility was varied between 40 and 100 mmHg. Hearts ejected into the native aorta whilst maintaining stable loading. 3. Increasing pulsatility elevated mean coronary flow +11.5 +/- 1.7 % under basal conditions. Co-infusion of adenosine sufficient to raise baseline flow 66 % markedly amplified this pulsatile perfusion response (+82. 6 +/- 14.3 % increase in mean flow above adenosine baseline), due to a leftward shift of the adenosine-coronary flow response curve at higher pulsatility. Flow augmentation with pulsatility was not linked to higher regional oxygen consumption, supporting direct rather than metabolically driven mechanisms. 4. Neither bradykinin, acetylcholine nor verapamil reproduced the synergistic amplification of mean flow by adenosine and higher pulsatility, despite being administered at doses matching basal flow change with adenosine. 5. ATP-sensitive potassium (KATP) activation (pinacidil) amplified the pulse-flow response 3-fold, although this remained significantly less than with adenosine. Co-administration of the phospholipase A2 inhibitor quinacrine virtually eliminated adenosine-induced vasodilatation, yet synergistic interaction between adenosine and pulse perfusion persisted, albeit at a reduced level. 6. Thus, adenosine and perfusion pulsatility specifically interact to enhance coronary flow. This synergy is partially explained by KATP agonist action and additional non-flow-dependent mechanisms, and may be important for modulating flow reserve during exercise or other high output states where

  7. 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

    OBJECTIVE: The regulation of normal sexual maturation and reproductive function is dependent on a precise hormonal regulation at hypothalamic, pituitary, and gonadal levels. The aim of this study was to investigate the neuroendocrine integrity of the pituitary-gonadal axis in patients with primary...... 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...... 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...

  8. Regulatory mechanisms of growth hormone secretion are sexually dimorphic.

    OpenAIRE

    Jaffe, C A; Ocampo-Lim, B; Guo, W; Krueger, K.; Sugahara, I; DeMott-Friberg, R; Bermann, M; Barkan, A. L.

    1998-01-01

    Sexually dimorphic growth hormone (GH) secretory pattern is important in the determination of gender-specific patterns of growth and metabolism in rats. Whether GH secretion in humans is also sexually dimorphic and the neuroendocrine mechanisms governing this potential difference are not fully established. We have compared pulsatile GH secretion profiles in young men and women in the baseline state and during a continuous intravenous infusion of recombinant human insulin-like growth factor I ...

  9. An Optimization Formulation for Characterization of Pulsatile Cortisol Secretion

    Directory of Open Access Journals (Sweden)

    Rose Taj Faghih

    2015-08-01

    Full Text Available Cortisol is released to relay information to cells to regulate metabolism and reaction to stress and inflammation. In particular, cortisol is released in the form of pulsatile signals. This low-energy method of signaling seems to be more efficient than continuous signaling. We hypothesize that there is a controller in the anterior pituitary that leads to pulsatile release of cortisol, and propose a mathematical formulation for such controller, which leads to impulse control as opposed to continuous control. We postulate that this controller is minimizing the number of secretory events that result in cortisol secretion, which is a way of minimizing the energy required for cortisol secretion; this controller maintains the blood cortisol levels within a specific circadian range while complying with the first order dynamics underlying cortisol secretion. We use an l0-norm cost function for this controller, and solve a reweighed l1-norm minimization algorithm for obtaining the solution to this optimization problem. We use 4 examples to illustrate the performance of this approach: (i a toy problem that achieves impulse control, (ii two examples that achieve physiologically plausible pulsatile cortisol release, (iii an example where the number of pulses is not within the physiologically plausible range for healthy subjects while the cortisol levels are within the desired range. This novel approach results in impulse control where the impulses and the obtained blood cortisol levels have a circadian rhythm and an ultradian rhythm that are in agreement with the known physiology of cortisol secretion. The proposed formulation is a first step in developing intermittent controllers for curing cortisol deficiency. This type of bio-inspired pulse controllers can be employed for designing non-continuous controllers in brain-machine interface design for neuroscience applications.

  10. Observation of the CSF pulsatile flow in the aqueduct using cine MRI with presaturation bolus tracking, 3; The pathophysiological significance of the pulsatile flow patterns in adult patients with ventriculomegaly

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Satoshi (Tokyo Medical Coll. (Japan))

    1992-06-01

    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).

  11. Automatic Germination Evaluation and Qualitative Analysis of Essential Oil of Mentha × piperita L. under the Influence of High Frequency Pulsatile Electromagnetic and Ultrasound Pulsatile Fields

    Directory of Open Access Journals (Sweden)

    Valentin SINGUREANU

    2015-04-01

    Full Text Available The study illustrates the influence of high frequency pulsatile electromagnetic fields and ultrasound pulsatile fields on Mentha × piperita L. seed germination and the quality of its essential oil. The physiological role of the above mentioned experimental factors was considered to be a catalyticall base point, improving germination percent, SVI (seedling vigor index, GVI (germination velocity index. All the biometric aspects of the germination process (seed area, seed perimeter, seed development on x and y radius, radicele length, hypocotyl length where determined using open free software, consolidating the general idea that scientific communities can improve and perfect open source projects. High frequency pulsatile electromagnetic fields (91.75% and ultrasound pulsatile fields (64.75% experimental variants gave higher germination percent compared to control (47.00%. Following the main terpenes determination, the same experimental variants obtained high accumulations of menthol, eugenol, thymol, eucalyptol, linalool and other components. These aspects can be scientifically sustained by the seedling vigor index marks obtained at high frequency pulsatile electromagnetic fields (1985.47 and ultrasound pulsatile fields (1480.09, creating the general premises for better development stages in the nursery sector. Raised accumulation of main therapeutical terpenes in Mentha × piperita L. must be supervised in further studies, when microscopically imagery of glandular trichomes and their density may lead to more profound conclusions.

  12. Fluid-structure interaction for nonlinear response of shells conveying pulsatile flow

    Science.gov (United States)

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

    2016-06-01

    Circular cylindrical shells with flexible boundary conditions conveying pulsatile flow and subjected to pulsatile pressure are investigated. The equations of motion are obtained based on the nonlinear Novozhilov shell theory via Lagrangian approach. The flow is set in motion by a pulsatile pressure gradient. The fluid is modeled as a Newtonian pulsatile flow and it is formulated using a hybrid model that contains the unsteady effects obtained from the linear potential flow theory and the pulsatile viscous effects obtained from the unsteady time-averaged Navier-Stokes equations. A numerical bifurcation analysis employs a refined reduced order model to investigate the dynamic behavior. The case of shells containing quiescent fluid subjected to the action of a pulsatile transmural pressure is also addressed. Geometrically nonlinear vibration response to pulsatile flow and transmural pressure are here presented via frequency-response curves and time histories. The vibrations involving both a driven mode and a companion mode, which appear due to the axial symmetry, are also investigated. This theoretical framework represents a pioneering study that could be of great interest for biomedical applications. In particular, in the future, a more refined model of the one here presented will possibly be applied to reproduce the dynamic behavior of vascular prostheses used for repairing and replacing damaged and diseased thoracic aorta in cases of aneurysm, dissection or coarctation. For this purpose, a pulsatile time-dependent blood flow model is here considered by applying physiological waveforms of velocity and pressure during the heart beating period. This study provides, for the first time in literature, a fully coupled fluid-structure interaction model with deep insights in the nonlinear vibrations of circular cylindrical shells subjected to pulsatile pressure and pulsatile flow.

  13. Pulsatile Drug Delivery System: Method and Technology Review

    Directory of Open Access Journals (Sweden)

    Kumar Amit

    2012-12-01

    Full Text Available Traditionally, drugs are released in an immediate or extended manner. A pulsatile drug release, where the drug is released rapidly after a well defined lag-time, could be advantageous for many drugs or therapies. As the pulsatile drug delivery achieve desired therapeutic effect and reducing side effect, so patient compliance can be obtained along with lowering dose frequency. These systems are designed according to the circadian rhythm of the body and the drug is released as a pulse. Diseases like asthma, peptic ulcers, cardiovascular ailments, arthritis and attention deficit syndrome in children and hypercholesterolemia can be cured by drugs, released by PDDS. Recent trends include Multiparticulate drug delivery systems that are especially suitable for achieving controlled or delayed release oral formulations with low risk of dose dumping, flexibility of blending to attain different release patterns as well as reproducible and short gastric residence time. Various methods and marketed technologies of PDDS such as Pulsincap TM, Diffucaps, CODAS, OROS and PULSYSTM are covered in this review.

  14. In vitro heart valve testing: steady versus pulsatile flow.

    Science.gov (United States)

    Black, M M; Hose, D R; Lamb, C J; Lawford, P V; Ralph, S J

    1994-03-01

    The design of artificial heart valves has traditionally been based on the development of a prototype device which was then subjected to extensive laboratory testing in order to confirm its suitability for clinical use. In the past the in vitro assessment of a valve's performance was based principally on the measurement of parameters such as pressure difference, regurgitation and, more recently, energy losses. Such measurements can be defined as being at the 'macro' level and rarely show any clinically significant differences amongst currently available prostheses. The analytical approach to flow through heart valves has previously been hampered by difficulties experienced in solving the relevant equations of flow particularly in the case of pulsatile conditions. Computational techniques are now available which enable appropriate solutions to be obtained for these problems and consequently provide an opportunity for detailed examination of the 'micro' level of flow disturbances exhibited by the different valves. This present preliminary study is designed to illustrate the use of such an analytical approach to the flow through prosthetic valves. A single topic has been selected for this purpose which is the comparative value of steady versus pulsatile flow testing. A bileaflet valve was chosen for the analysis and a mathematical model of this valve in the aortic position of the Sheffield Pulse Duplicator was created. The theoretical analysis was carried out using a commercially available Computational Fluid Dynamics package, namely, FIDAP, on a SUN MICROSYSTEMS 10-30 workstation.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Cinematics and sticking of heart valves in pulsatile flow test.

    Science.gov (United States)

    Köhler, J; Wirtz, R

    1991-05-01

    The aim of the project was to develop laboratory test devices for studies of the cinematics and sticking behaviour of technical valve protheses. The second step includes testing technical valves of different types and sizes under static and dynamic conditions. A force-deflection balance was developed in order to load valve rims by static radial forces until sticking or loss of a disc (sticking- and clamping-mould point) with computer-controlled force deflection curves. A second deflection device was developed and used for prosthetic valves in the aortic position of a pulsatile mock circulation loop with simultaneous video-cinematography. The stiffness of technical valve rims varied between 0.20 (St. Jude) and about 1.0 N/micron (metal rim valves). The stiffness decreased significantly with increasing valve size. Sticking under pulsatile flow conditions was in good agreement with the static deflection measurements. Hence, valve sticking with increasing danger of thrombus formation is more likely with a less stiff valve rim. In the case of forces acting perpendicularly to the pendulum axis, the clamping mould-point of the valve can be reached, followed by disc dislodgement. PMID:1864654

  16. Predictable pulsatile release of tramadol hydrochloride for chronotherapeutics of arthritis.

    Science.gov (United States)

    Dabhi, Chandu; Randale, Shivsagar; Belgamwar, Veena; Gattani, Surendra; Tekade, Avinash

    2010-07-01

    The present investigation deals with the development of a pH and time-dependent press-coated pulsatile drug delivery system for delivering drugs into the colon. The system consists of a drug containing core, coated by a combination of natural polymer Delonix regia gum (DRG) and hydroxypropyl methylcellulose (HPMC K4M) in various proportions, which controls the onset of release. The whole system was coated with methacrylic acid copolymers, which not only prevents the drug release in the stomach, but also prolongs the lag time. Tramadol HCl was used as a model drug and varying combinations of DRG and HPMC K4M were used to achieve the desired lag time before rapid and complete release of the drug in the colon. It was observed that the lag time depends on the coating ratio of DRG to HPMC and also on press coating weight. Drug release was found to be increased by 15-30% in the presence of colonic microbial flora. The results showed the capability of the system in achieving pulsatile release for a programmable period of time and pH-dependent release to attain colon-targeted delivery. PMID:20524906

  17. Increasing pulmonary artery pulsatile flow improves hypoxic pulmonary hypertension in piglets.

    Science.gov (United States)

    Courboulin, Audrey; Kang, Chantal; Baillard, Olivier; Bonnet, Sebastien; Bonnet, Pierre

    2015-01-01

    Pulmonary arterial hypertension (PAH) is a disease affecting distal pulmonary arteries (PA). These arteries are deformed, leading to right ventricular failure. Current treatments are limited. Physiologically, pulsatile blood flow is detrimental to the vasculature. In response to sustained pulsatile stress, vessels release nitric oxide (NO) to induce vasodilation for self-protection. Based on this observation, this study developed a protocol to assess whether an artificial pulmonary pulsatile blood flow could induce an NO-dependent decrease in pulmonary artery pressure. One group of piglets was exposed to chronic hypoxia for 3 weeks and compared to a control group of piglets. Once a week, the piglets underwent echocardiography to assess PAH severity. At the end of hypoxia exposure, the piglets were subjected to a pulsatile protocol using a pulsatile catheter. After being anesthetized and prepared for surgery, the jugular vein of the piglet was isolated and the catheter was introduced through the right atrium, the right ventricle and the pulmonary artery, under radioscopic control. Pulmonary artery pressure (PAP) was measured before (T0), immediately after (T1) and 30 min after (T2) the pulsatile protocol. It was demonstrated that this pulsatile protocol is a safe and efficient method of inducing a significant reduction in mean PAP via an NO-dependent mechanism. These data open up new avenues for the clinical management of PAH. PMID:25993379

  18. 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

  19. Pulsatile Drug Delivery System Based on Electrohydrodynamic Method

    CERN Document Server

    Zheng, Yi; Hu, Junqiang; Gao, Wenle

    2012-01-01

    Electrohydrodynamic (EHD) generation, a commonly used method in BioMEMS, plays a significant role in the pulsatile drug delivery system for a decade. In this paper, an EHD based drug delivery system is well designed, which can be used to generate a single drug droplet as small as 2.83 nL in 8.5 ms with a total device of 2\\times2\\times3 mm^3, and an external supplied voltage of 1500 V. Theoretically, we derive the expressions for the size and the formation time of a droplet generated by EHD method, while taking into account the drug supply rate, properties of liquid, gap between two electrodes, nozzle size, and charged droplet neutralization. This work proves a repeatable, stable and controllable droplet generation and delivery system based on EHD method experimentally as well as theoretically.

  20. EFFECTS OF VASCULAR ZERO-STRESS STATE ON PULSATILE BLOOD FLOW

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In this paper, blood flow in artery was treated as the flow under equilibrium state (the steady flow under mean pressure) combined with the periodically small pulsatile flow. Based on vascular zero-stress state[1], the pulsatile strains according to the radial and axial displacements of blood vessel were obtained. With the use of Hooke’s law, the pulsatile strains and the corresponding Cauchy stresses were connected, so the corresponding wall motion equations could be established here. By solving the linearized Navier-Stokes equations, the analytic expressions of the blood flow velocities and the vascular displacements could be obtained, and the influence of the circumferential and axial stretch ratio on pulsatile blood flow and vascular motion was discussed in details.

  1. Design and In Vitro Evaluation of Compression-coated Pulsatile Release Tablets of Losartan Potassium

    OpenAIRE

    Bajpai, M.; Singh, D. C. P.; Bhattacharya, A.; Singh, A.

    2012-01-01

    In majority of individuals blood pressure rises in the early morning hours, which lead to serious cardiovascular complications. Formulation of pulsatile system makes it possible to deliver drug at definite period of time when symptoms of the disease condition are most critical. The purpose of the present work was to develop pulsatile release tablet of losartan potassium for chronotherapy in hypertension. The prepared system consisted of a core tablet coated with versatile and safe hydrophilic...

  2. Optimization Studies on Compression Coated Floating-Pulsatile Drug Delivery of Bisoprolol

    OpenAIRE

    Swati C. Jagdale; Bari, Nilesh A.; Kuchekar, Bhanudas S.; Chabukswar, Aniruddha R.

    2013-01-01

    The purpose of the present work was to design and optimize compression coated floating pulsatile drug delivery systems of bisoprolol. Floating pulsatile concept was applied to increase the gastric residence of the dosage form having lag phase followed by a burst release. The prepared system consisted of two parts: a core tablet containing the active ingredient and an erodible outer shell with gas generating agent. The rapid release core tablet (RRCT) was prepared by using superdisintegrants w...

  3. Three-dimensional shape construction of pulsatile tissue from ultrasonic movies for assistance of clinical diagnosis

    Science.gov (United States)

    Fukuzawa, Masayuki; Kawaguchi, Hikari; Yamada, Masayoshi; Nakamori, Nobuyuki; Kitsunezuka, Yoshiki

    2010-02-01

    Three-dimensional shape of pulsatile tissue due to blood flow, which is one of key diagnostic features in ischemia, has been constructed from 2D ultrasonic movies for assisting clinical diagnosis. The 2D ultrasonic movies (640x480pixels/frame, 8bits/pixel, 33ms/frame) were taken with a conventional ultrasonic apparatus and an ultrasonic probe, while measuring the probe orientations with a compact tilt-sensor. The 2D images of pulsatile strength were obtained from each 2D ultrasonic movie by evaluating a heartbeat-frequency component calculated by Fourier transform of a series of pixel values sampled at each pixel. The 2D pulsatile images were projected into a 3D domain to obtain a 3D grid of pulsatile strength according to the probe orientations. The 3D shape of pulsatile tissue was constructed by determining the iso-surfaces of appropriate strength in the 3D grid. The shapes of pulsatile tissue examined in neonatal crania clearly represented the 3D structures of several arteries such as middle cerebral artery, which is useful for diagnosis of ischemic diseases. Since our technique is based on feature extraction in tissue dynamics, it is also useful for homogeneous tissue, for which conventional 3D ultrasonogram is unsuitable due to unclear tissue boundary.

  4. Beneficial Effect of Short Pretransplant Period of Hypothermic Pulsatile Perfusion of the Warm-Ischemic Kidney after Cold Storage: Experimental Study

    Directory of Open Access Journals (Sweden)

    Alberto Lázaro

    2016-01-01

    Full Text Available Warm ischemia (WI produces a significant deleterious effect in potential kidney grafts. Hypothermic machine perfusion (HMP seems to improve immediate graft function after transplant. Our aim was to analyze the effect of short pretransplant periods of pulsatile HMP on histology and renal injury in warm-ischemic kidneys. Twelve minipigs were used. WI was achieved in the right kidney by applying a vascular clamp for 45 min. After nephrectomy, autotransplant was performed following one of two strategies: cold storage of the kidneys or cold storage combined with perfusion in pulsatile HMP. The graft was removed early to study renal morphology, inflammation (fibrosis, and apoptosis. Proinflammatory activity and fibrosis were less pronounced after cold storage of the kidneys with HMP than after cold storage only. The use of HMP also decreased apoptosis compared with cold storage only. The detrimental effects on cells of an initial and prolonged period of WI seem to improve with a preservation protocol that includes a short period of pulsatile HMP after cold storage and immediately before the transplant, in comparison with cold storage only.

  5. 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

  6. A pulsatile pump for cardiopulmonary bypass and its clinical use.

    Science.gov (United States)

    Sasaki, Y; Kawai, T; Nishiyama, K; Murayama, Y; Toda, S; Wada, T; Kitaura, K; Sato, S; Kadowaki, M; Kanki, Y

    1988-09-01

    A pulsatile pump driven by a coil spring, which was designed and constructed by us, is described in this report. It consists of two main parts, a disposable blood chamber and a driving section. The blood chamber has two leaflet valves and a piston, which is covered with two bellofram rolling diaphragms and moves into the housing to draw in and eject the blood. The driving section consists of three cams, an electric motor and a coil spring. The ejection force is wholly produced by the compressed coil spring and is transmitted to the piston in the blood chamber by a rod. This pump allows the ejection pressure, the beat rates, and the stroke volume all to be changed independently. The performance of the pump was tested by using a circulation model where the beat rate was adjusted from 30 to 250 bpm. The output subsequently increased from 0.8 l/min to 5.7 l/min and the stroke volume, from 20.4 ml to 36.7 ml. This new pump has been used for clinical cardiopulmonary bypasses in 24 patients of open heart surgery and the pressure traces during perfusion resembled those of the patients' own hearts. PMID:3230723

  7. 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.)

  8. Kisspeptin regulates gonadotropin-releasing hormone secretion in gonadotropin-releasing hormone/enhanced green fluorescent protein transgenic rats

    Institute of Scientific and Technical Information of China (English)

    Haogang Xue; Chunying Yang; Xiaodong Ge; Weiqi Sun; Chun Li; Mingyu Qi

    2013-01-01

    Kisspeptin is essential for activation of the hypothalamo-pituitary-gonadal axis. In this study, we established gonadotropin-releasing hormone/enhanced green fluorescent protein transgenic rats. Rats were injected with 1, 10, or 100 pM kisspeptin-10, a peptide derived from full-length kisspeptin, into the arcuate nucleus and medial preoptic area, and with the kisspeptin antagonist peptide 234 into the lateral cerebral ventricle. The results of immunohistochemical staining revealed that pulsatile luteinizing hormone secretion was suppressed after injection of antagonist peptide 234 into the lateral cerebral ventricle, and a significant increase in luteinizing hormone level was observed after kisspeptin-10 injection into the arcuate nucleus and medial preoptic area. The results of an enzyme-linked immunosorbent assay showed that luteinizing hormone levels during the first hour of kisspeptin-10 infusion into the arcuate nucleus were significantly greater in the 100 pM kisspeptin-10 group than in the 10 pM kisspeptin-10 group. These findings indicate that kisspeptin directly promotes gonadotropin-releasing hormone secretion and luteinizing hormone release in gonadotropin-releasing hormone/enhanced green fluorescent protein transgenic rats. The arcuate nucleus is a key component of the kisspeptin-G protein-coupled receptor 54 signaling pathway underlying regulating luteinizing hormone pulse secretion.

  9. Bioidentical Hormones and Menopause

    Science.gov (United States)

    ... Balance › Bioidentical Hormones and Menopause Fact Sheet Bioidentical Hormones and Menopause January, 2012 Download PDFs English Espanol ... take HT for symptom relief.) What are bioidentical hormones? Bioidentical hormones are identical to the hormones that ...

  10. Hormone Data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Hormones quantified from marine mammal and sea turtle tissue provide information about the status of each animal sampled, including its sex, reproductive status and...

  11. Pulsatile Flow through Annular Space Bounded by Outer Porous Cylinder and an Inner Cylinder of Permeable Material

    Science.gov (United States)

    Rashidi, M. M.; Keimanesh, M.; Rajvanshi, S. C.; Wasu, S.

    2012-10-01

    This study investigates the problem of pulsatile flow of an incompressible Newtonian fluid through annular space bounded by an outer porous cylinder and an inner cylinder of permeable material. The coupled flow has been analyzed by solving Navier-Stokes equations in the free fluid region and Darcy's equation in the porous region. Beaver-Joseph slip-condition has been used at the free fluid-permeable medium interface. The similarity transformation for the governing equations gives a system of nonlinear ordinary differential equations which are analytically solved by the homotopy analysis method (HAM). The analytical solutions have been obtained in the form of a series. An admissible interval for the convergence of the series solutions has been indicated. Graphical results are presented to show the influence of different parameters on velocity profiles, pressure drop, and skin friction. Comparison between the solutions obtained by the HAM and the numerical solution shows good agreement.

  12. In vitro pulsatility analysis of axial-flow and centrifugal-flow left ventricular assist devices.

    Science.gov (United States)

    Stanfield, J Ryan; Selzman, Craig H

    2013-03-01

    Recently, continuous-flow ventricular assist devices (CF-VADs) have supplanted older, pulsatile-flow pumps, for treating patients with advanced heart failure. Despite the excellent results of the newer generation devices, the effects of long-term loss of pulsatility remain unknown. The aim of this study is to compare the ability of both axial and centrifugal continuous-flow pumps to intrinsically modify pulsatility when placed under physiologically diverse conditions. Four VADs, two axial- and two centrifugal-flow, were evaluated on a mock circulatory flow system. Each VAD was operated at a constant impeller speed over three hypothetical cardiac conditions: normo-tensive, hypertensive, and hypotensive. Pulsatility index (PI) was compared for each device under each condition. Centrifugal-flow devices had a higher PI than that of axial-flow pumps. Under normo-tension, flow PI was 0.98 ± 0.03 and 1.50 ± 0.02 for the axial and centrifugal groups, respectively (p centrifugal pumps, respectively (p = 0.01). Under hypotension, PI was 0.73 ± 0.02 and 0.78 ± 0.02 for the axial and centrifugal groups, respectively (p = 0.13). All tested CF-VADs were capable of maintaining some pulsatile-flow when connected in parallel with our mock ventricle. We conclude that centrifugal-flow devices outperform the axial pumps from the basis of PI under tested conditions.

  13. FORMULATION AND EVALUATION OF PULSATILE DRUG DELIVERY SYSTEM CONTAINING INDOMETHACIN USING NATURAL POLYMERS

    Directory of Open Access Journals (Sweden)

    Kamat Akshay Ramesh

    2013-02-01

    Full Text Available Aim of the present work was to formulate and evaluate an oral pulsatile drug delivery system using natural superdisintegrants and natural polymers to achieve time release of Indomethacin, based on chronopharmaceutical approach for the treatment of rheumatoid arthritis. Pulsatile delivery system is capable of delivering drug when and where it required most. By administering the system at bedtime, but releasing drug as a burst after the lag time (during peak morning hours thereby delivering the drug when and where it is required the most with decreased side effects, dose size and prolonged action. The press-coated pulsatile release tablet contains Indomethacin in the inner rapid release core tablet formulated by direct compression method using plantago ovata mucilage and modified agar as superdisintegrants and the external coat formulated using natural polymers such as dammar gum, chitosan, xanthan gum and gaur gum by both direct and wet granulation method. The prepared press-coated pulsatile tablets were evaluated for various pre-compressional and post-compressional parameters. In-vitro release profiles of pulsatile device during 10 h studies were found to have very good sustaining efficacy. Formulation code A1, A8, B2 and B7 were selected as the best formulations with formulation B2 containing xanthan gum and dammar gum in the ratio 2:1 having maximum lag time of 7 h 15 min.

  14. 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

  15. 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.

  16. Algorithmic complexity of growth hormone release in humans.

    Science.gov (United States)

    Prank, K; Wagner, M; Brabant, G

    1997-01-01

    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. 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.

  18. Analytical and experimental characterization of a miniature calorimetric sensor in pulsatile flow

    CERN Document Server

    Gelderblom, H; Haartsen, J R; Rutten, M C M; van de Ven, A A F; van de Vosse, F N; 10.1017/S0022112010004234

    2011-01-01

    The behaviour of a miniature calorimetric sensor, which is under consideration for catheter-based coronary artery flow assessment, is investigated in both steady and pulsatile tube flow. The sensor is composed of a heating element operated at constant power, and two thermopiles that measure flow-induced temperature differences over the sensor surface. An analytical sensor model is developed, which includes axial heat conduction in the fluid and a simple representation of the solid wall, assuming a quasi-steady sensor response to the pulsatile flow. To reduce the mathematical problem, described by a two-dimensional advection-diffusion equation, a spectral method is applied. A Fourier transform is then used to solve the resulting set of ordinary differential equations and an analytical expression for the fluid temperature is found. To validate the analytical model, experiments with the sensor mounted in a tube have been performed in steady and pulsatile water flow with various amplitudes and Strouhal numbers. E...

  19. 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.

  20. Evaluation of a physiologic pulsatile pump system for neonate-infant cardiopulmonary bypass support.

    Science.gov (United States)

    Undar, A; Masai, T; Inman, R; Beyer, E A; Mueller, M A; McGarry, M C; Frazier, O H; Fraser, C D

    1999-01-01

    An alternate physiologic pulsatile pump (PPP) system was designed and evaluated to produce sufficient pulsatility during neonate-infant open heart surgery. This hydraulically driven pump system has a unique "dual" pumping chamber mechanism. The first chamber is placed between the venous reservoir and oxygenator and the second chamber between the oxygenator and patient. Each chamber has two unidirectional tricuspid valves. Stroke volume (0.2-10 ml), upstroke rise time (10-350 msec), and pump rate (2-250 beats per minute [bpm]) can be adjusted independently to produce adequate pulsatility. This system has been tested in 3-kg piglets (n = 6), with a pump flow of 150 ml/kg/min, a pump rate of 150 bpm, and a pump ejection time of 110 msec. After initiation of cardiopulmonary bypass (CPB), all animals were subjected to 25 minutes of hypothermia to reduce the rectal temperatures to 18 degrees C, 60 minutes of deep hypothermic circulatory arrest (DHCA), then 10 minutes of cold perfusion with a full pump flow, and 40 minutes of rewarming. During CPB, mean arterial pressures were kept at less than 50 mm Hg. Mean extracorporeal circuit pressure (ECCP), the pressure drop of a 10 French aortic cannula, and the pulse pressure were 67+/-9, 21+/-6, and 16+/-2 mm Hg, respectively. All values are represented as mean+/-SD. No regurgitation or abnormal hemolysis has been detected during these experiments. The oxygenator had no damping effect on the quality of the pulsatility because of the dual chamber pumping mechanism. The ECCP was also significantly lower than any other known pulsatile system. We conclude that this system, with a 10 French aortic cannula and arterial filter, produces adequate pulsatility in 3 kg piglets. PMID:9952008

  1. Behavioral treatment of pulsatile tinnitus and headache following traumatic head injury. Objective polygraphic assessment of change.

    Science.gov (United States)

    Hegel, M T; Martin, J B

    1998-10-01

    Pulsatile tinnitus is a disorder that can be extremely disabling. Nonetheless, it has not been well-researched in the fields of psychology or behavioral therapy. This article describes the evaluation and behavioral treatment of a gentleman with pulsatile tinnitus. The evaluation included polygraphic assessment of vasomotor and electromyographic function both before and after treatment. The results show that the combination of lifestyle modifications and specific behavioral interventions were successful in modifying not only self-report indices of functioning, but also the underlying physiology related to the disorder. The potential role of the various treatment components and the value of including polygraphic assessment for informing treatment and evaluating outcome are discussed.

  2. Clinical evaluation of pulsatile flow mode of Terumo Capiox centrifugal pump.

    Science.gov (United States)

    Nishida, H; Uesugi, H; Nishinaka, T; Uwabe, K; Aomi, S; Endo, M; Koyanagi, H; Oshiyama, H; Nogawa, A; Akutsu, T

    1997-07-01

    The Terumo Capiox centrifugal pump system possesses an automatic priming function in which the motor repeatedly stops and runs intermittently to eliminate air bubbles in the circuit through the micropores of the hollow-fiber membrane oxygenator. By modifying this mechanism, we have developed a pulsatile flow mode. In this mode, maximum and minimum pump rotational speeds can be independently set every 20 rpm in the range of 0 to 3,000 rpm. The duration of the pump run at maximum and minimum speeds can also be independently set every 0.1 s in the range of 0.2 to 15 s. In a clinical trial, after obtaining the desired flow rate, 2.4 L/min/m2 in nonpulsatile flow mode, a pulsatile flow mode of 60 cycles/min (with 1 cycle being maximum speed for 0.4 s and minimum speed for 0.6 s) was obtained by adding and subtracting 500 rpm to and from the rotational speed in nonpulsatile flow mode. Pulse pressures in the femoral artery and in the circuit just proximal to the perfusion cannula (6.5 mm Sarns high flow cannula with metal tip) were measured in 5 patients who underwent pulsatile cardiopulmonary bypass (CPB) for a coronary artery bypass graft (CABG), and compared to pulse pressures obtained by intraaortic balloon pumping (IABP) in 3 patients and by the pulsatile mode of the 3M Delphin pump in 3 patients. The platelet count, free hemoglobin, and beta-thromboglobulin (beta-TG) were measured and compared with measurements from another 5 patients who underwent nonpulsatile CPB. Although the pulse pressure measured in the circuit was 180 mm Hg on average, the pressure in the femoral artery was only 15 to 40 mm Hg with a mean of 20 mm Hg. In the same patients, 60 to 80 mm Hg pulse pressure was obtained with IABP. The pulse pressure obtained with the Delphin pump was not more than that obtained with the Terumo pump. There were no significant differences in percents of preoperative levels of platelet counts (pulsatile, 87.6 +/- 15.8% and nonpulsatile, 72.4 +/- 40.6%), free

  3. Beyond the Virtual Intracranial Stenting Challenge 2007: non-Newtonian and flow pulsatility effects.

    Science.gov (United States)

    Cavazzuti, Marco; Atherton, Mark; Collins, Michael; Barozzi, Giovanni

    2010-09-17

    The Virtual Intracranial Stenting Challenge 2007 (VISC'07) is becoming a standard test case in computational minimally invasive cerebrovascular intervention. Following views expressed in the literature and consistent with the recommendations of a report, the effects of non-Newtonian viscosity and pulsatile flow are reported. Three models of stented cerebral aneurysms, originating from VISC'07 are meshed and the flow characteristics simulated using commercial computational fluid dynamics (CFD) software. We conclude that non-Newtonian and pulsatile effects are important to include in order to discriminate more effectively between stent designs.

  4. Hormone impostors

    Energy Technology Data Exchange (ETDEWEB)

    Colborn, T.; Dumanoski, D.; Myers, J.P.

    1997-01-01

    This article discusses the accumulating evidence that some synthetic chemicals disrupt hormones in one way or another. Some mimic estrogen and others interfere with other parts of the body`s control or endocrine system such as testosterone and thyroid metabolism. Included are PCBs, dioxins, furans, atrazine, DDT. Several short sidebars highlight areas where there are or have been particular problems.

  5. 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)], e-mail: gongs@ccmu.edu.cn

    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.

  6. Endocrine Glands & Their Hormones

    Science.gov (United States)

    ... Characteristics of Hormones Endocrine Glands & Their Hormones Pituitary & Pineal Glands Thyroid & Parathyroid Glands Adrenal Gland Pancreas Gonads Other ... hormone secretion. « Previous (Characteristics of Hormones) Next (Pituitary & Pineal Glands) » Contact Us | Privacy Policy | Accessibility | FOIA | File Formats ...

  7. Oxygen analyzer

    Science.gov (United States)

    Benner, William H.

    1986-01-01

    An oxygen analyzer which identifies and classifies microgram quantities of oxygen in ambient particulate matter and for quantitating organic oxygen in solvent extracts of ambient particulate matter. A sample is pyrolyzed in oxygen-free nitrogen gas (N.sub.2), and the resulting oxygen quantitatively converted to carbon monoxide (CO) by contact with hot granular carbon (C). Two analysis modes are made possible: (1) rapid determination of total pyrolyzable oxygen obtained by decomposing the sample at 1135.degree. C., or (2) temperature-programmed oxygen thermal analysis obtained by heating the sample from room temperature to 1135.degree. C. as a function of time. The analyzer basically comprises a pyrolysis tube containing a bed of granular carbon under N.sub.2, ovens used to heat the carbon and/or decompose the sample, and a non-dispersive infrared CO detector coupled to a mini-computer to quantitate oxygen in the decomposition products and control oven heating.

  8. Development of a new introduction technique for the pulsatile catheter pump

    NARCIS (Netherlands)

    Mihaylov, D; Kik, C; Elstrodt, J; Verkerke, GJ; Blanksma, PK; Rakhorst, G

    1997-01-01

    The pulsatile catheter (PUCA) pump is an intraventricular blood pump that can be introduced into the left ventricular cavity through a superficial artery (trans arterially) or directly through the thoracic aorta during open chest conditions. When positioned, the pump aspirates blood from the left ve

  9. Evaluation of the optimal driving mode during left ventricular assist with pulsatile catheter pump in calves

    NARCIS (Netherlands)

    Mihaylov, D; Verkerke, GJ; Blanksma, PK; Elstrodt, J; de Jong, ED; Rakhorst, G

    1999-01-01

    The pulsatile catheter (PUCA) pump, a left ventricular assist device, was tested during acute experiments in calves using asynchronous and EGG-synchronous assist modes. The aim of the study is to compare ECG-synchronous and asynchronous assist and to find the optimal driving mode for the PUCA pump w

  10. IN-VITRO EVALUATION OF THE INFLUENCE OF PULSATILE INTRAVENTRICULAR PUMPING ON VENTRICULAR PRESSURE PATTERNS

    NARCIS (Netherlands)

    RAKHORST, G; VERKERKE, GJ; HENSENS, AG; DEMUINCK, ED; BLANKSMA, PK; PILLON, M; JUFER, M

    1994-01-01

    The Pulsatile catheter (PUCA) pump consists of a single port membrane pump connected to an indwelling valved catheter. This so-called transarterial blood pump was originally designed to be introduced through a superficial artery into the left ventricular cavity to pump blood from the left ventricle

  11. The effect of pulsatile cardiopulmonary bypass on lung function in elderly patients

    NARCIS (Netherlands)

    Engels, Gerwin E.; Dodonov, Mikhail; Rakhorst, Gerhard; van Oeveren, Willem; Milano, Aldo D.; Gu, Y. John; Faggian, Giuseppe

    2014-01-01

    Purpose: Cardiopulmonary bypass is still a major cause of lung injury and delay in pulmonary recovery after cardiac surgery. Although it has been shown that pulsatile flow induced by intra-aortic balloon pumping is beneficial for preserving lung function, it is not clear if the same beneficial effec

  12. Three-dimensional flow separation over a surface-mounted hemisphere in pulsatile flow

    Science.gov (United States)

    Carr, Ian A.; Plesniak, Michael W.

    2016-01-01

    Flow separation over a surface-mounted obstacle is prevalent in numerous applications. Previous studies of 3D separation around protuberances have been limited to steady flow. In biological and geophysical flows, pulsatile conditions are frequently encountered, yet this situation has not been extensively studied. Primarily motivated by our previous studies of the flow patterns observed in various human vocal fold pathologies such as polyps, our research aimed to fill this gap in the knowledge concerning unsteady 3D flow separation. This is achieved by characterizing velocity fields surrounding the obstacle, focused primarily on the vortical flow structures and dynamics that occur around a hemispheroid in pulsatile flow. As part of this study, two-dimensional, instantaneous and phase-averaged particle image velocimetry data in both steady and pulsatile flows are presented and compared. Coherent vortical flow structures have been identified by their swirling strength. This analysis revealed flow structures with dynamics dependent on the pulsatile forcing function. A mechanism to explain the formation and observed dynamics of these flow structures based on the self-induced velocity of vortex rings interacting with the unsteady flow is proposed.

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

    NARCIS (Netherlands)

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

    2010-01-01

    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 Netherland

  14. A new pulsatile total artificial heart using a single centrifugal pump.

    Science.gov (United States)

    Imachi, K; Chinzei, T; Abe, Y; Mabuchi, K; Imanishi, K; Yonezawa, T; Kouno, A; Ono, T; Atsumi, K; Isoyama, T

    1991-01-01

    A new pulsatile total artificial heart (TAH) system, combining a single centrifugal pump (CFP) with two three-way valves, was developed. One port of each three-way valve was connected to the inlet and outlet of a CFP, respectively. The other two ports of each valve ware connected to the right and left atrium, pulmonary artery, and aorta. The CFP can perfuse the pulmonary and systemic circulation alternately with pulsatile flow. A prototype system composed of a Sarns' CFP and solenoid valves was connected to a mock circulatory system resulting in 1) a pulsatile TAH that could be produced with a single CFP, 2) 5 L/min of pulsatile output with a normal flow wave form that can be obtained alternately on the right and left side by switching the solenoid valves, and 3) flow balance between the left and the right that could be controlled easily by the length of switching duration. This new system could be miniaturized and is feasible for a totally implantable TAH.

  15. A pulsatile cardiopulmonary bypass system that prevents negative pressure at the membrane oxygenator.

    Science.gov (United States)

    Komoda, T; Maeta, H; Imawaki, S; Shiraishi, Y; Arioka, I; Fukunaga, S; Tanaka, S; Nasu, N

    1993-01-01

    Negative pressure is a problem in pulsatile cardiopulmonary bypass (CPB). To avoid this, the authors designed a pulsatile CPB system containing a Sarns centrifugal pump (CP) and a Univox membrane oxygenator, in which the inertial flow is not obstructed by the CP. In both an in vitro study and a clinical study, negative pressure was not observed in the arterial line of the CPB circuit when this system was used. When a roller pump (RP) was used, however, instead of a CP, negative pressure did occur. In a clinical study using this system, mean pulse pressure was 36 mmHg and hemolysis, expressed as the rate of rise in plasma free hemoglobin from 10 to 70 min of CPB, was 26.2 mg/dl/hr, which did not exceed that seen with a pulsatile CPB using an RP instead of a CP. The hemolysis seen in the study caused no clinical problems. Thus, pulsatile CPB using a CP and Univox membrane oxygenator should be considered for clinical use to prevent the occurrence of negative pressure.

  16. Feasibility of Pump Speed Modulation for Restoring Vascular Pulsatility with Rotary Blood Pumps.

    Science.gov (United States)

    Ising, Mickey S; Sobieski, Michael A; Slaughter, Mark S; Koenig, Steven C; Giridharan, Guruprasad A

    2015-01-01

    Continuous flow (CF) left ventricular assist devices (LVAD) diminish vascular pressure pulsatility, which may be associated with clinically reported adverse events including gastrointestinal bleeding, aortic valve insufficiency, and hemorrhagic stroke. Three candidate CF LVAD pump speed modulation algorithms designed to augment aortic pulsatility were evaluated in mock flow loop and ischemic heart failure (IHF) bovine models by quantifying hemodynamic performance as a function of mean pump speed, modulation amplitude, and timing. Asynchronous and synchronous copulsation (high revolutions per minute [RPM] during systole, low RPM during diastole) and counterpulsation (low RPM during systole, high RPM during diastole) algorithms were tested for defined modulation amplitudes (±300, ±500, ±800, and ±1,100 RPM) and frequencies (18.75, 37.5, and 60 cycles/minute) at low (2,900 RPM) and high (3,200 RPM) mean LVAD speeds. In the mock flow loop model, asynchronous, synchronous copulsation, and synchronous counterpulsation algorithms each increased pulse pressure (ΔP = 931%, 210%, and 98% and reduced left ventricular external work (LVEW = 20%, 22%, 16%). Similar improvements in vascular pulsatility (1,142%) and LVEW (40%) were observed in the IHF bovine model. Asynchronous modulation produces the largest vascular pulsatility with the advantage of not requiring sensor(s) for timing pump speed modulation, facilitating potential clinical implementation. PMID:26102173

  17. Development and optimization of press coated floating pulsatile drug delivery of sumatriptan succinate.

    Science.gov (United States)

    Jagdale, Swati C; Pawar, Chandrakala R

    2014-01-01

    Floating pulsatile is combined approach designed according to circadian rhythm to deliver the drug at right time, in right quantity and at right site as per pathophysiological need of disease with prolong gastric residence and lag phase followed by burst release. As the migraine follows circadian rhythm in which headache is more painful at the awakening time, the dosage form should be given during night time to release drug when pain get worsen. Present work deals with formulation and optimization of floating pulsatile tablet of sumatriptan succinate. Core tablet containing crospovidone as superdisintegrant (10%) showed burst release. Lag time was maintained using swellable polymer as polyoxN12K and xanthum gum. 3(2) experimental design was carried out. Developed formulations were evaluated for physical characteristics, in vitro and in vivo study. Optimized batch F2 with concentration of polyox N12K (73.43%) and xanthum gum (26.56%) of total polymer weight showed floating lag time 15±2 sec, drug content 99.58±0.2 %, hardness 6±0.2 Kg/cm(2) and drug release 99.54±2% with pulsatile manner followed lag period of 7±0.1h. In vivo x-ray study confirms prolong gastric residence of system. Programmable pulsatile release has been achieved by formulation F2 which meet demand of chronotherapeutic objective of migraine. PMID:24893996

  18. Clinical effectiveness of centrifugal pump to produce pulsatile flow during cardiopulmonary bypass in patients undergoing cardiac surgery.

    Science.gov (United States)

    Gu, Y John; van Oeveren, Willem; Mungroop, Hubert E; Epema, Anne H; den Hamer, Inez J; Keizer, Jorrit J; Leuvenink, Ron P; Mariani, Massimo A; Rakhorst, Gerhard

    2011-02-01

    Although the centrifugal pump has been widely used as a nonpulsatile pump for cardiopulmonary bypass (CPB), little is known about its performance as a pulsatile pump for CPB, especially on its efficacy in producing hemodynamic energy and its clinical effectiveness. We performed a study to evaluate whether the Rotaflow centrifugal pump produces effective pulsatile flow during CPB and whether the pulsatile flow in this setting is clinically effective in adult patients undergoing cardiac surgery. Thirty-two patients undergoing CPB for elective coronary artery bypass grafting were randomly allocated to a pulsatile perfusion group (n = 16) or a nonpulsatile perfusion group (n = 16). All patients were perfused with the Rotaflow centrifugal pump. In the pulsatile group, the centrifugal pump was adjusted to the pulsatile mode (60 cycles/min) during aortic cross-clamping, whereas in the nonpulsatile group, the pump was kept in its nonpulsatile mode during the same period of time. Compared with the nonpulsatile group, the pulsatile group had a higher pulse pressure (P centrifugal pump is associated with a small gain of EEP and SHE, which does not seem to be clinically effective in adult cardiac surgical patients.

  19. 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

  20. Formulation and Evaluation of Chronomodulated Pulsatile Drug Delivery System of Salbutamol Sulphate

    Directory of Open Access Journals (Sweden)

    Anusha V

    2015-12-01

    Full Text Available Chronotherapy denotes the therapy in which the release of the drug in the body is allowed to match with the circadian rhythm of the disease, such that the required action of the drug is shown with minimal side effects. The main interesting fact of chronotherapy is its ability to deliver the drug in required concentrations during the time of its greatest need such that synchronizing circadian rhythm of diseases or symptoms. Pulsatile drug delivery system for Salbutamol sulphate was formulated initially as core tablets followed by formulation of pulsatile tablets using press-coated technology. Core tablets were formulated using various concentrations of superdisintegrant (Sodium starch glycolate, cross povidone and diluents (MCC & Dicalcium phosphate. The core tablets were then compressed into pulsatile tablets using combinations of HPMC K 100M and Eudragit L 100, Eudragit S 100 in various concentrations. Core tablets were evaluated and based on the dissolution studies trial T3was optimized as it shows lower disintegration time and faster drug release. Then the pulsatile tablets were evaluated for various tests and drug release studies were conducted for 2 hours in 0.1N HCl followed by pH 6.8 buffer and the trial S6 was optimized which showed satisfactory greater lag time of about 6 hours with satisfactory drug release which contains a combination of HPMC K15M (20mg, Eudragit L 100 (50mg, Eudragit S100 (60mg. Pulsatile tablets were formulated utilizing press coated technology and the combination of polymers provided required lag time with satisfactory dissolution profile.

  1. Hormonal changes in humans during spaceflight.

    Science.gov (United States)

    Strollo, F

    1999-01-01

    Readers of this review may feel that there is much more that we do not know about space endocrinology than what we know. Several reasons for this state of affairs have been given: 1. the complexity of the field of endocrinology with its still increasing number of known hormones, releasing factors and precursors, and of the interactions between them through various feedback mechanisms 2. the difficulty in separating the microgravity effects from the effects of stress from launch, isolation and confinement during flight, reentry, and postflight re-adaptation 3. the experimental limitations during flight, such as limited number of subjects, limited number of samples, impossibility of collecting triple samples for pulsatile hormones like growth hormone 4. the disturbing effects of countermeasures used by astronauts 5. the inadequacy of postflight samples for conclusions about inflight values 6. limitations of conclusions from animal experiments and space simulation studies The endocrinology field is divided in to nine systems or axes, which are successively reviewed: 1. Rapid bone demineralization in the early phase of spaceflight that, when unopposed, leads to catastrophic effects after three months but that slows down later. The endocrine mechanism, apart from the effect of exercise as a countermeasure, is not yet understood. 2. The hypothalamic-pituitary-adrenal axis is involved in stress reactions, which complicate our understanding and makes postflight analysis dubious. 3. In the hypothalamic-pituitary-gonadal axis, pulsatility poses a problem for obtaining representative values (e.g., for luteinizing hormone). Reproduction of rats in space is possible, but much more needs to be known about this aspect, particularly in women, before the advent of space colonies, but also in males because some evidence for reversible testicular dysfunction in space has been found. 4. The hypothalamic-pituitary-somato-mammotrophic axis involves prolactin and growth hormone. The

  2. DynPeak : An algorithm for pulse detection and frequency analysis in hormonal time series

    CERN Document Server

    Vidal, Alexandre; Médigue, Claire; Fabre, Stéphane; Clément, Frédérique

    2011-01-01

    The endocrine control of the reproductive function is often studied from the analysis of luteinizing hormone (LH) pulsatile secretion by the pituitary gland. Whereas measurements in the cavernous sinus cumulate anatomical and technical difficulties, LH levels can be easily assessed from jugular blood. However, plasma levels result from a convolution process due to clearance effects when LH enters the general circulation. Simultaneous measurements comparing LH levels in the cavernous sinus and jugular blood have revealed clear differences in the pulse shape, the amplitude and the baseline. Besides, experimental sampling occurs at a relatively low frequency (typically every 10 min) with respect to LH highest frequency release (one pulse per hour) and the resulting LH measurements are noised by both experimental and assay errors. As a result, the pattern of plasma LH may be not so clearly pulsatile. Yet, reliable information on the InterPulse Intervals (IPI) is a prerequisite to study precisely the steroid feedb...

  3. The effect of the pulsatile electromagnetic field in children suffering from bronchial asthma.

    Science.gov (United States)

    Sadlonova, J; Korpas, J; Salat, D; Miko, L; Kudlicka, J

    2003-01-01

    From the bibliography it is well known that pulsatile electromagnetic field has an anti-inflammatory and analgesic effect. It causes vasodilatation, myorelaxation, hyper-production of connective tissue and activation of the cell membrane. Therefore our aim was to study the possible therapeutic effect of pulsatile electromagnetic field in asthmatic children. Forty-two children participating in this study were divided in two groups. The 1st group consisting of 21 children (11 females, 10 males, aged 11.8 +/- 0.4 yr) was treated by pulsatile electromagnetic field and pharmacologically. The 2nd group served as control, consisting also of 21 children (11 females, 10 males, aged 11.7 +/- 0.3 yr) and was treated only pharmacologically. Therapeutic effect of the pulsatile electromagnetic field was assessed on the basis of pulmonary tests performed by means of a Spirometer 100 Handi (Germany). The indexes FVC, IVC, ERV, IRV, FEV1, FEV1/FVC%, MEF75,50,25, PEF, PIF and the changes of the flow-volume loop were also registered. The pulsatile electromagnetic field was applied by means of the device MTU 500H, Therapy System (Brno, Czech Republic) for 5 days, two times daily for 30 minutes (magnetic induction: 3 mT, frequency: 4 Hz as recommended by the manufacturer). The results in children of the 1st group showed an improvement of FVC of about 70 ml, IVC of about 110 ml, FEV1 of about 80 ml, MEF75 of about 30 ml, PEF of about 480 ml, PIF of about 550 ml. The increases of ERV, IRV and FEV1/FVC and decreases of MEF25,50 were statistically insignificant. The results in the 2nd group were less clear. The flow-volume loop showed a mild improvement in 14 children. This improvement in the 2nd group was less significant. The clinical status of children and their mood became better. We believe that the pulsatile electro-magnetotherapy in children suffering from asthma is effective. On the basis of our results we can recommend it as a complementary therapy. PMID:14708875

  4. Evaluation of pulsatile and nonpulsatile flow in capillaries of goat skeletal muscle using intravital microscopy.

    Science.gov (United States)

    Lee, J J; Tyml, K; Menkis, A H; Novick, R J; Mckenzie, F N

    1994-11-01

    It is commonly believed that pulsatile flow generated by the pumping action of the heart is dampened out by the time it reaches the microcirculation. In clinical practice, most of the cardiopulmonary bypass pumps and ventricular assist devices are nonpulsatile. To test the hypothesis that pulsatile flow generated by the heart does exist at the microvascular level, intravital microscopy of a large animal model (goat) was developed to visualize and to videorecord the surface microcirculation of the flexor carpi ulnaris muscle from the right forelimb. Density of perfused capillaries and red blood cell velocity in capillaries were measured in five goats during pulsatile perfusion provided by the heart and during a subsequent 3-hr period of nonpulsatile perfusion provided by a centrifugal ventricular assist device (Centrimed, Sarns 3M) that bypassed the heart. Throughout the experiment, the heart rate, innominate artery mean blood pressure, and flow remained unchanged. During the pulsatile regimen, velocities showed regular fluctuations that coincided with the period of the cardiac cycle (range of periods: 0.5-0.8 sec). The peak velocity amplitudes (range: 0.25-0.55 mm/sec) correlated directly with the amplitude of the pulse pressure. During the nonpulsatile regimen, no such correlations were seen. During pulsatile flow and during the 3-hr nonpulsatile period, capillary density remained stable at 24 capillaries/mm of test line but there were significant increases in red cell velocity, from 0.8 to 1.2 mm/sec (P < 0.05), and in coefficient of variation of velocity (used as an index of flow heterogeneity), from 19 to 34% (P < 0.05). We conclude that (1) pulsatility exists in the capillary bed and that it directly correlates with the pumping action of the heart and (2) nonpulsatile flow produced by the ventricular assist device does not cause an acute deterioration in microvascular perfusion. We interpret the increase in heterogeneity of flow as an early sign of

  5. The Effect of Pulsatile Versus Nonpulsatile Blood Flow on Viscoelasticity and Red Blood Cell Aggregation in Extracorporeal Circulation

    OpenAIRE

    Ahn, Chi Bum; Kang, Yang Jun; Kim, Myoung Gon; Yang, Sung; Lim, Choon Hak; Son, Ho Sung; Kim, Ji Sung; Lee, So Young; Son, Kuk Hui; Sun, Kyung

    2016-01-01

    Background Extracorporeal circulation (ECC) can induce alterations in blood viscoelasticity and cause red blood cell (RBC) aggregation. In this study, the authors evaluated the effects of pump flow pulsatility on blood viscoelasticity and RBC aggregation. Methods Mongrel dogs were randomly assigned to two groups: a nonpulsatile pump group (n=6) or a pulsatile pump group (n=6). After ECC was started at a pump flow rate of 80 mL/kg/min, cardiac fibrillation was induced. Blood sampling was perfo...

  6. Reproducibility of aortic pulsatility measurements from ECG-gated abdominal CTA in patients with abdominal aortic aneurysms

    Science.gov (United States)

    Manduca, Armando; Fletcher, Joel G.; Wentz, Robert J.; Shields, Raymond C.; Vrtiska, Terri J.; Siddiki, Hassan; Nielson, Theresa

    2009-02-01

    Purpose: ECG-gated abdominal CT angiography with reconstruction of multiple, temporally overlapping CT angiography datasets has been proposed for measuring aortic pulsatility. The purpose of this work is to develop algorithms to segment the aorta from surrounding structures from CTA datasets across cardiac phases, calculate registered centerlines and measurements of regional aortic pulsatility in patients with AAA, and to assess the reproducibility of these measurements. Methods: ECG-gated CTA was performed with a temporal resolution of 165 ms, reconstructed to 1 mm slices ranging at 14 cardiac phase points. Data sets were obtained from 17 patients on which two such scans were performed 6 to 12 months apart. Automated segmentation, centerline generation, and registration of centerlines between phases was performed, followed by calculation of cross-sectional areas and regional and local pulsatility. Results: Pulsatility calculations for the supraceliac region were very reproducible between earlier and later scans of the same patient, with average differences less than 1% for pulsatility values ranging from 2% to 13%. Local radial pulsatilities were also reproducible to within ~1%. Aneurysm volume changes between scans can also be quantified. Conclusion: Automated segmentation, centerline generation, and registration of temporally resolved CTA datasets permit measurements of regional changes in cross-sectional area over the course of the cardiac cycle (i.e., regional aortic pulsatility). These measurements are reproducible between scans 6-12 months apart, with differences in aortic areas reflecting both aneurysm remodeling and changes in blood pressure. Regional pulsatilities ranged from 2 to 13% but were reproducible at the 1% level.

  7. Numerical reconstruction of pulsatile blood flow from 4D computer tomography angiography data

    CERN Document Server

    Lovas, Attila; Csobo, Elek; Szilágyi, Brigitta; Sótonyi, Péter

    2015-01-01

    We present a novel numerical algorithm developed to reconstuct pulsatile blood flow from ECG-gated CT angiography data. A block-based optimization method was constructed to solve the inverse problem corresponding to the Riccati-type ordinary differential equation that can be deduced from conservation principles and Hooke's law. Local flow rate for 5 patients was computed in 10cm long aorta segments that are located 1cm below the heart. The wave form of the local flow rate curves seems to be realistic. Our approach is suitable for estimating characteristics of pulsatile blood flow in aorta based on ECG gated CT scan thereby contributing to more accurate description of several cardiovascular lesions.

  8. Analysis of Pulsatile Flow of Blood in a Porous Channel under Effect of Magnetic Field

    Directory of Open Access Journals (Sweden)

    Mitali Sarma

    2011-11-01

    Full Text Available To study the effect of magnetic field on pulsatile flow of blood in a porous channel a numerical model has been developed. An approximate solution is presented to the problem of pulsatile flow of blood in a porous channel in presence of transverse magnetic field. The blood is assumed to be an incompressible non Newtonian fluid. To reduce the equation of motion to an ordinary differential equation, a dimensionless variable is used. Numerical results were obtained for different values of the magnetic parameter, frequency parameter and Reynolds number. It is observed that when the Hartmann number increases, the fluid velocity as well as magnitude as well as magnitude of mass flux decrease.

  9. Artificial Heart Rejects High Tech? Lessens Learnt from Non-pulsatile VAD with Straight Impeller Vanes

    OpenAIRE

    Qian, Kun-xi

    2007-01-01

    Despite the progresses in developing pulsatile impeller pump and impeller total heart, as well as in applying streamlined impeller vanes, the best results in application of artificial heart pumps have been achieved by nonpulsatile univentricular assist pump with straight impeller vanes until now. It seems all efforts and successes have been done in vain because artificial heart rejects Hi-Tech! This paper recalls some important achievements in R&D of artificial heart in past 25 years and shar...

  10. Pulsatile ocular blood flow among normal subjects and patients with high tension glaucoma

    OpenAIRE

    Agarwal Harish; Gupta Viney; Sihota Ramanjit; Singh Kulwant

    2003-01-01

    Purpose: To estimate pulsatile ocular blood flow (POBF) among normal subjects and to compare various parameters in eyes of primary open angle glaucoma with high intraocular pressure (IOP). Methods: POBF was estimated in 95 eyes of 95 normal subjects above the age of 40 years and in 35 eyes of 35 primary open angle glaucoma patients using the OBF system (OBF Labs Ltd., UK). Correlation of age, gender, IOP, pulse amplitude, pulse volume and pulse rate with POBF was studied. POBF values were ...

  11. Vortex propagation around a wall-mounted obstacle in pulsatile flow

    Science.gov (United States)

    Carr, Ian A.; Plesniak, Michael W.

    2015-11-01

    Wall-mounted obstacles are prevalent in nature and engineering applications. Physiological flows observed in human vocal fold pathologies, such as polyps, can be modeled by flow over a wall-mounted protuberance. Despite their prevalence, studies of wall-mounted obstacles have been restricted to steady (constant velocity) freestream flow. In biological and geophysical applications, pulsatile flow is much more common, yet effects of pulsatility on the wake of a wall-mounted obstacle remain to be extensively studied. This study aims to characterize the complex physics produced in this unsteady, separated flow. Experiments were performed in a low-speed wind tunnel with a set of rotating vanes, which produce the pulsatile inflow waveform. Instantaneous and phase-averaged particle image velocimetry (PIV) results acquired around a hemispherical obstacle are presented and compared. A mechanism based on self-induced vortex propagation, analogous to that in vortex rings, is proposed to explain the observed dynamics of coherent structures. Predictions of the propagation velocity based on analytical expressions for vortex rings in a viscous fluid are compared to the experimentally measured propagation velocity. Effects of the unsteady boundary layer on the observed physics are explored. This material is based in part upon work supported by the National Science Foundation under Grant Number CBET-1236351, and GW Center for Biomimetics and Bioinspired Engineering (COBRE).

  12. FABRICATION OF PULSATILE DELIVERY MULTIPARTICULATE SYSTEM OF POORLY WATER SOLUBLE CARVEDILOL PHOSPHATE

    Directory of Open Access Journals (Sweden)

    Singh DK

    2012-09-01

    Full Text Available Pulsatile drug delivery system is required to satisfy the needs of chronotherapy. Among solids, multiparticulates have its own advantages. Pulsatile drug delivery system provides better therapy with many of the actives. Rupturable pulsatile drug delivery system consists of a drug core; swelling layer of a super disintegrant; and an insoluble, water-permeable polymeric coating. Upon water ingress, the swellable layer expands, resulting in the rupturing of outer membrane followed by drug release. The active pharmaceutical ingredient selected was Carvedilol Phosphate, deposited on sugar pellets as first layer. The second layer composed of swelling excipient, had crospovidone, L–substituted hydroxy propyl cellulose and sodium starch glycolate. Third and the outer most layer was based on ethyl cellulose. The release after lag time was fast and complete, when crospovidone was used as a swelling agent. In contrast, a sustained release was achieved after the lag time, when L–substituted hydroxy propyl cellulose and sodium starch glycolate were used as swelling agents. Fast release would be preferable in the present case. Optimal level of crospovidone to achieve a fast and complete release of Carvedilol phosphate was 33%. Outer membrane, formed using aqueous dispersion of ethyl cellulose was suitable enough to rupture sufficiently ensuring fast drug release, compared to stronger ethyl cellulose membrane formed using organic solution. It was possible to design multiparticulates of carvedilol phosphate having a suitable release profile.

  13. An experimental study of pressure losses in pulsatile flows through rigid and pulsating stenosis.

    Science.gov (United States)

    Rabinovitz, R; Degani, D; Gutfinger, C; Milo, S

    1984-11-01

    The time-dependent pressure curves of a pulsatile flow across rigid and pulsating stenoses were investigated experimentally in a laboratory simulator of the outflow tract of the heart right ventricle. The experiments were performed within the range of physiological conditions of frequency and flow rate. The experimental setup consisted of a closed flow system which was operated by a pulsatile pump, and a test chamber which enabled checking different modes of stenosis. Rigid constrictions were simulated by means of axisymmetric blunt-ended annular plugs with moderate-to-severe area reductions. The pulsating stenosis consisted of a short starling resistor device operated by a pulsating external pressure which was synchronized by the pulsatile flow. It was found that the shape of the time-dependent pressure curve upstream of the stenosis was different in the case of rigid stenosis than in the pulsating one. Potential clinical applications of the work may relate to diagnosis of the type of stenosis in the congenital heart disease known as Tetralogy of Fallot. PMID:6513525

  14. Alkaline phosphatase in osteoblasts is down-regulated by pulsatile fluid flow

    Science.gov (United States)

    Hillsley, M. V.; Frangos, J. A.

    1997-01-01

    It is our hypothesis that interstitial fluid flow plays a role in the bone remodeling response to mechanical loading. The fluid flow-induced expression of three proteins (collagen, osteopontin, and alkaline phosphatase) involved in bone remodeling was investigated. Rat calvarial osteoblasts subjected to pulsatile fluid flow at an average shear stress of 5 dyne/cm2 showed decreased alkaline phosphatase (AP) mRNA expression after only 1 hour of flow. After 3 hours of flow, AP mRNA levels had decreased to 30% of stationary control levels and remained at this level for an additional 5 hours of flow. Steady flow (4 dyne/cm2 fluid shear stress), in contrast, resulted in a delayed and less dramatic decrease in AP mRNA expression to 63% of control levels after 8 hours of flow. The reduced AP mRNA expression under pulsatile flow conditions was followed by reduced AP enzyme activity after 24 hours. No changes in collagen or osteopontin mRNA expression were detected over 8 hours of pulsatile flow. This is the first time fluid flow has been shown to affect gene expression in osteoblasts.

  15. Hormone Replacement Therapy

    Science.gov (United States)

    ... before and during menopause, the levels of female hormones can go up and down. This can cause ... hot flashes and vaginal dryness. Some women take hormone replacement therapy (HRT), also called menopausal hormone therapy, ...

  16. Thyroid Hormone Treatment

    Science.gov (United States)

    ... Giving Workplace Giving Other Ways to Donate Thyroid Hormone Treatment Thyroid hormone is used in two situations: ... prevent recurrence or progression of their cancer. THYROID HORMONE REPLACEMENT THERAPY Many people have a thyroid gland ...

  17. Growth hormone test

    Science.gov (United States)

    ... page: //medlineplus.gov/ency/article/003706.htm Growth hormone test To use the sharing features on this page, please enable JavaScript. The growth hormone test measures the amount of growth hormone in ...

  18. 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

  19. Cyclic variations of high-frequency ultrasonic backscattering from blood under pulsatile flow.

    Science.gov (United States)

    Huang, Chih-Chung

    2009-08-01

    It was shown previously that ultrasonic scattering from whole blood varies during the flow cycle under pulsatile flow both in vitro and in vivo. It has been postulated that the cyclic variations of the backscattering signal are associated with red blood cell (RBC) aggregation in flowing whole blood. To obtain a better understanding of the relationship between blood backscattering and RBC aggregation behavior for pulsatile flowing blood, the present study used high-frequency ultrasound to characterize blood properties. The backscattering signals from both whole blood and an RBC suspension at different peak flow velocities (from 10 to 30 cm/s) and hematocrits (20% and 40%) under pulsatile flow (stroke rate of 20 beats/min) were measured with 3 single-element transducers at frequencies of 10, 35, and 50 MHz in a mock flow loop. To avoid the frequency response problem of a Doppler flowmeter, the integrated backscatter (IB) and flow velocity as functions of time were calculated directly using RF signals from flowing blood. The experimental results showed that cyclic variations of the IB curve were clearly observed at a low flow velocity and a hematocrit of 40% when using 50 MHz ultrasound, and that these variations became weaker as the peak flow velocity increased. However, these cyclic variations were detected only at 10 cm/s when using 10 MHz ultrasound. These results demonstrate that a high flow velocity can stop the formation of rouleaux and that a high hematocrit can promote RBC aggregation to produce cyclic variations of the backscattering signal under pulsatile flow. In addition, slight cyclic variations of the IB curve for an RBC suspension were observed at 35 and 50 MHz. Furthermore, the peak of the IB curve from whole blood led the peak of the velocity waveform when using high-frequency ultrasound, which could be explained by the assumption that a rapid flow can promote RBC aggregation under pulsatile flow. Together, the experimental results showed that the

  20. Pulsatility Index of Blood Echogenicity of the Human Radial and Common Carotid Arteries: Relation with Age and Stroke

    Energy Technology Data Exchange (ETDEWEB)

    Bok, Tae Hoon; Kong, Qi; Nam, Kweon Ho; Choi, Jay Chol; Paeng, Dong Guk [Department of Ocean System Engineering, Jeju National University, Jeju (Korea, Republic of)

    2012-10-15

    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.

  1. Impact of the postpump resistance on pressure-flow waveform and hemodynamic energy level in a neonatal pulsatile centrifugal pump.

    Science.gov (United States)

    Wang, Shigang; Haines, Nikkole; Richardson, J Scott; Dasse, Kurt A; Undar, Akif

    2009-01-01

    This study tested the impact of different postpump resistances on pulsatile pressure-flow waveforms and hemodynamic energy output in a mock extracorporeal system. The circuit was primed with a 40% glycerin-water mixture, and a PediVAS centrifugal pump was used. The pre- and postpump pressures and flow rates were monitored via a data acquisition system. The postpump resistance was adjusted using a Hoffman clamp at the outlet of the pump. Five different postpump resistances and rotational speeds were tested with nonpulsatile (NP: 5000 RPM) and pulsatile (P: 4000 RPM) modes. No backflow was found when using pulsatile flow. With isoresistance, increased arterial resistances decreased pump flow rates (NP: from 1,912 ml/min to 373 ml/min; P: from 1,485 ml/min to 288 ml/min), increased postpump pressures (NP: from 333 mm Hg to 402 mm Hg; P: from 223 mm Hg to 274 mm Hg), and increased hemodynamic energy output with pulsatile mode. Pump flow rate correlated linearly with rotational speed (RPMs) of the pump, whereas postpump pressures and hemodynamic energy outputs showed curvilinear relationships with RPMs. The maximal pump flow rate also increased from 618 ml/min to 4,293 ml/min with pulsatile mode and from 581 ml/min to 5,665 ml/min with nonpulsatile mode. Results showed that higher postpump resistance reduced the pump flow range, and increased postpump pressure and surplus hemodynamic energy output with pulsatile mode. Higher rotational speeds also generated higher pump flow rates, postpump pressures, and increased pulsatility.

  2. [Hormonal dysnatremia].

    Science.gov (United States)

    Karaca, P; Desailloud, R

    2013-10-01

    Because of antidiuretic hormone (ADH) disorder on production or function we can observe dysnatremia. In the absence of production by posterior pituitary, central diabetes insipidus (DI) occurs with hypernatremia. There are hereditary autosomal dominant, autosomal recessive or X- linked forms. When ADH is secreted but there is an alteration on his receptor AVPR2, it is a nephrogenic diabetes insipidus in acquired or hereditary form. We can make difference on AVP levels and/or on desmopressine response which is negative in nephrogenic forms. Hyponatremia occurs when there is an excess of ADH production: it is a euvolemic hypoosmolar hyponatremia. The most frequent etiology is SIADH (syndrome of inappropriate secretion of ADH), a diagnostic of exclusion which is made after eliminating corticotropin deficiency and hypothyroidism. In case of brain injury the differential diagnosis of cerebral salt wasting (CSW) syndrome has to be discussed, because its treatment is perfusion of isotonic saline whereas in SIADH, the treatment consists in administration of hypertonic saline if hyponatremia is acute and/or severe. If not, fluid restriction demeclocycline or vaptans (antagonists of V2 receptors) can be used in some European countries. Four types of SIADH exist; 10 % of cases represent not SIADH but SIAD (syndrome of inappropriate antidiuresis) due to a constitutive activation of vasopressin receptor that produces water excess. c 2013 Published by Elsevier Masson SAS. PMID:24356291

  3. Effect of Ubiquinol on Serum Reproductive Hormones of Amenorrhic Patients.

    Science.gov (United States)

    Thakur, A S; Littaru, G P; Funahashi, I; Painkara, U S; Dange, N S; Chauhan, P

    2016-07-01

    In neuroendocrine system the increase in oxidative status is produced by a glucocorticoid-dependent and transcriptional increase in pro-oxidative drive, with concurrent inhibition of the antioxidant defense system, ultimately leading to increased neuronal cell death. Functional hypothalamic disturbances and neuroendocirne aberrations have both short and long term consequences for reproductive health. Understandably, an impaired or diminished hypothalamic-pituitary-ovarian axis leads to anovulation and hypoestrogenism. Anovulation is directly linked to the neurohormonal and hormonal background of Functional Hypothalamic Amenorrhea. Impairment of pulsatile Gonadotropin Releasing Hormone secretion causes the impairment of pulsatile Lutenizing Hormone (LH) and Follicle Stimulating Hormone (FSH) secretion. The importance of oxidative stress in various pituitary disorders suggesting a possible clinical usefulness of antioxidant molecules like the lipophilic antioxidant Ubiquinol. Coenzyme Q10 or Ubiquinol is an essential part of the cell energy-producing system of mitochondria. However, it is also a powerful lipophilic antioxidant, protecting lipoproteins and cell membranes from autooxidation. Due to these unique actions Ubiquinol is used in clinical practice as an antioxidants for neurodegenerative diseases. So to identify the role of Ubiquinol on reproductive hormones FSH and LH, we have included 50 infertile patients of age group of 20-40, which are mostly amenorrhic. Out of 50 only 30 patients were in continuous follow up after supplementing them with 150 mg of Ubiquinol every day for 4 months. The hormonal levels were estimated by Enzyme Linked Immuno Sorbent Assay technique at follicular phase. The result suggests that FSH concentration is increased up to three times (from 3.10 ± 2.70 to 10.09 ± 6.93) but remains within the normal limit (P  0.05). The supplementation of 150 mg of Ubiquinol may reduce the oxidative stress in neuroendocrine system which

  4. Dynamic, Sex-Differential STAT5 and BCL6 Binding to Sex-Biased, Growth Hormone-Regulated Genes in Adult Mouse Liver

    OpenAIRE

    Zhang, Yijing; Laz, Ekaterina V.; Waxman, David J.

    2012-01-01

    Sex-dependent pituitary growth hormone (GH) secretory patterns determine the sex-biased expression of >1,000 genes in mouse and rat liver, affecting lipid and drug metabolism, inflammation, and disease. A fundamental biological question is how robust differential expression can be achieved for hundreds of sex-biased genes simply based on the GH input signal pattern: pulsatile GH stimulation in males versus near-continuous GH exposure in females. STAT5 is an essential transcriptional mediator ...

  5. Strategies for the Determination of Plant Hormones.

    Science.gov (United States)

    Davis, Gregory C.; And Others

    1985-01-01

    Describes methods for isolating, purifying, and analyzing plant hormones (molecules involved in plant growth regulation and development). The presentation reflects the historical development of analyses, beginning with bioassays and ending with novel immunochemical assays. (JN)

  6. Dendro-dendritic bundling and shared synapses between gonadotropin-releasing hormone neurons

    OpenAIRE

    Campbell, Rebecca E.; Gaidamaka, Galina; Han, Seong-Kyu; Herbison, Allan E.

    2009-01-01

    The pulsatile release of gonadotropin-releasing hormone (GnRH) is critical for mammalian fertility, but the mechanisms underlying the synchronization of GnRH neurons are unknown. In the present study, the full extent of the GnRH neuron dendritic tree was visualized by patching and filling individual GnRH neurons with biocytin in acute brain slices from adult GnRH-green fluorescent protein (GFP) transgenic mice. Confocal analysis of 42 filled GnRH neurons from male and female adult mice reveal...

  7. DEVELOPMENT OF BIPHASIC PULSATILE RELEASE MINI-TABLETS SYSTEM OF POORLY WATER SOLUBLE CARVEDILOL PHOSPHATE

    Directory of Open Access Journals (Sweden)

    D. K. Singh

    2015-05-01

    Full Text Available Objective: Carvedilol Phosphate is indicated for the treatment of mild-to-severe chronic heart failure of ischemic or cardiomyopathic origin. The ultimate goal of pulsatile release mini-tablets to deliver a drug to the specific site and then to maintain the desired plasma drug concentration at particular site in chronotherapeutic manner. Among solids, multiparticulate delivery have its own advantages. Pulsatile drug delivery system provides better therapy with many of the actives. Rupturable pulsatile mini-tablet consists of a drug core; swelling layer of a super disintegrant; an insoluble, water-permeable polymeric and enteric coating. Upon water access, the swellable layer expands, resulting in the rupturing of outer membrane followed by drug release. There were no drug release ob served in acid phase. The active pharmaceutical ingredient selected was Carvedilol Phosphate, in core mini-tablets. The second layer composed of swelling excipient, had crospovidone, Croscarmellose sodium and sodium starch glycolate. Third and the outer most layer was based on ethyl cellulose and enteric polymer. The release after lag time was fast and complete, when crospovidone was used as a swelling agent. In contrast, a sustained release was achieved after the lag time, when croscarmellose sodium and sodium starch glycolate were used as swelling agents. Fast release would be preferable in the present case. Optimal level of crospovidone to achieve a fast and complete release of Carvedilol phosphate was 30%. Outer membrane, formed using ethyl cellulose was suitable enough to rupture sufficiently ensuring fast drug release in upper portion of small intestine. It was possible to design multiparticulate of carvedilol phosphate having a suitable release profile.

  8. Pulsatile flow with heat transfer of dusty magnetohydrodynamic Ree-Eyring fluid through a channel

    Energy Technology Data Exchange (ETDEWEB)

    Shawky, Hameda Mohammed [Faculty of Women, AL-Azhar University, Department of Mathematics, Cairo (Egypt)

    2009-08-15

    The flow due to the pulsatile pressure gradient of dusty non-Newtonian fluid with heat transfer in a channel is considered. The system is stressed by an external magnetic field. The non-Newtonian fluid under consideration is obeying the rheological equation of state due to Ree-Eyring's stress-strain relation. The equations of momentum and energy have been solved by using Lightill method. The velocity and temperature distributions of the two phase of the dusty fluid are obtained. The effects of various physical parameters of distributions the problem on these distributions are discussed and illustrated graphically through a set of figure. (orig.)

  9. A Pulsatile Flow Phantom for Image-Guided HIFU Hemostasis of Blood Vessels

    Science.gov (United States)

    Greaby, Robyn; Vaezy, Shahram

    2005-03-01

    A pulsatile flow phantom for studying ultrasound image-guided acoustic hemostasis in a controlled environment has been developed. An ex vivo porcine carotid artery was attached to the phantom and embedded in a visually and ultrasonically transparent gel. Heparinized porcine blood was pumped through the phantom. Power-Doppler and B-mode ultrasound were used to remotely target the HIFU focus to the site of a needle puncture. In nine trials, complete hemostasis was achieved after an average HIFU application of 55 +/- 34 seconds. The vessels remained patent after treatment. With this phantom, it will be possible to do controlled studies of ultrasound image-guided acoustic hemostasis.

  10. Effect of Applied Magnetic Field on Pulsatile Flow of Blood in a Porous Channel

    Directory of Open Access Journals (Sweden)

    Sarfraz Ahmed

    2011-11-01

    Full Text Available An approximate solution is presented to the problem of pulsatile flow of blood in porous channel in presence of induced magnetic field. The blood is assumed to be an incompressible Non Newtonian fluid. To reduce the equation of motion to an ordinary differential equation, a dimensionless variable is used. Numerical results were obtained for different values of the magnetic parameter, frequency parameter and Reynolds number. It is observed that when the magnetic parameter, the Hartmann number increases, the velocity as well as magnitude of mass flux decreases. For non magnetic case the paper reduces to the problem investigated by Wang

  11. Neoglycoenzyme-Gated Mesoporous Silica Nanoparticles: Toward the Design of Nanodevices for Pulsatile Programmed Sequential Delivery.

    Science.gov (United States)

    Díez, Paula; Sánchez, Alfredo; de la Torre, Cristina; Gamella, María; Martínez-Ruíz, Paloma; Aznar, Elena; Martínez-Máñez, Ramón; Pingarrón, José M; Villalonga, Reynaldo

    2016-03-01

    We report herein the design of a stimulus-programmed pulsatile delivery system for sequential cargo release based on the use of a lactose-modified esterase as a capping agent in phenylboronic acid functionalized mesoporous silica nanoparticles. The dual-release mechanism was based on the distinct stability of the cyclic boronic acid esters formed with lactose residues and the long naturally occurring glycosylation chains in the modified neoglycoenzyme. Cargo delivery in succession was achieved using glucose and ethyl butyrate as triggers. PMID:26966914

  12. THE STEADY/PULSATILE FLOW AND MACROMOLECULAR TRANSPORT IN T-BIFURCATION BLOOD VESSELS

    Institute of Scientific and Technical Information of China (English)

    李丁; 温功碧

    2003-01-01

    A numerical analysis of the steady and pulsatile, macromolecular( such as lowdensity lipopotein ( LDL ), Albumin ) transport in T-bifurcation was proposed. Theinfluence of Reynolds number and mass flow ratio etc. parameters on the velocity field andmass transport were calculated. The computational results predict that the blood flow factorsaffect the macromolecular distribution and the transport across the wall, it shows thathemodynamic play an important role in the process of atherosclerosis . The LDL and Albuminconcentration on the wall varies most greatly in flow bifurcation area where the wall shearstress varies greatly at the branching vessel and the atherosclerosis often appears there.

  13. Frequency-Dependent Neural Activity in Patients with Unilateral Vascular Pulsatile Tinnitus

    OpenAIRE

    Lv, Han; Zhao, Pengfei; Liu, Zhaohui; Wang, Guopeng; Zeng, Rong; Yan, Fei; Dong, Cheng; Zhang, Ling; Li, Rui; Wang, Peng; Li, Ting; Gong, Shusheng; Wang, Zhenchang

    2016-01-01

    Previous resting-state functional magnetic resonance imaging (rs-fMRI) studies have shown that neurological changes are important findings in vascular pulsatile tinnitus (PT) patients. Here, we utilized rs-fMRI to measure the amplitude of low-frequency fluctuations (ALFF) in forty patients with unilateral PT and forty age-, gender-, and education-matched normal control subjects. Two different frequency bands (slow-4, 0.027–0.073 Hz, and slow-5, 0.010–0.027 Hz, which are more sensitive to subc...

  14. Physiologic benefits of pulsatile perfusion during mechanical circulatory support for the treatment of acute and chronic heart failure in adults.

    Science.gov (United States)

    Guan, Yulong; Karkhanis, Tushar; Wang, Shigang; Rider, Alan; Koenig, Steven C; Slaughter, Mark S; El Banayosy, Aly; Undar, Akif

    2010-07-01

    A growing population experiencing heart failure (100,000 patients/year), combined with a shortage of donor organs (less than 2200 hearts/year), has led to increased and expanded use of mechanical circulatory support (MCS) devices. MCS devices have successfully improved clinical outcomes, which are comparable with heart transplantation and result in better 1-year survival than optimal medical management therapies. The quality of perfusion provided during MCS therapy may play an important role in patient outcomes. Despite demonstrated physiologic benefits of pulsatile perfusion, continued use or development of pulsatile MCS devices has been widely abandoned in favor of continuous flow pumps owing to the large size and adverse risks events in the former class, which pose issues of thrombogenic surfaces, percutaneous lead infection, and durability. Next-generation MCS device development should ideally implement designs that offer the benefits of rotary pump technology while providing the physiologic benefits of pulsatile end-organ perfusion.

  15. Pulsatile Support Mode of BJUT-II Ventricular Assist Device (VAD) has Better Hemodynamic Effects on the Aorta than Constant Speed Mode: A Primary Numerical Study.

    Science.gov (United States)

    Gu, Kaiyun; Gao, Bin; Chang, Yu; Zeng, Yi

    2016-01-01

    BACKGROUND BJUT-II VAD is a novel left ventricular assist device (LVADs), directly implanted into the ascending aorta. The pulsatile support mode is proposed to achieve better unloading performance than constant speed mode. However, the hemodynamic effects of this support mode on the aorta are still unclear. The aim of this study was to clarify the hemodynamic effects BJUT-II VAD under pulsatile support mode on the aorta. MATERIAL AND METHODS Computational fluid dynamics (CFD) studies, based on a patient-specific aortic geometric model, were conducted. Wall shear stress (WSS), averaged WSS (avWSS), oscillatory shear index (OSI), and averaged helicity density (Ha) were calculated to compare the differences in hemodynamic effects between pulsatile support mode and constant speed mode. RESULTS The results show that avWSS under pulsatile support mode is significantly higher than that under constant speed mode (0.955Pa vs. 0.675Pa). Similarly, the OSI value under pulsatile mode is higher than that under constant speed mode (0.104 vs. 0.057). In addition, Ha under pulsatile mode for all selected cross-sections is larger than that under constant mode. CONCLUSIONS BJUT-II VAD, under pulsatile control mode, may prevent atherosclerosis lesions and aortic remodeling. The precise effects of pulsatile support mode on atherosclerosis and aortic remodeling need to be further studied in animal experiments. PMID:27363758

  16. Pulsatile microvascular blood flow imaging by short-time Fourier transform analysis of ultrafast laser holographic interferometry

    CERN Document Server

    Puyo, L; Rancillac, A; Simonutti, M; Paques, M; Sahel, J A; Fink, M; Atlan, M

    2015-01-01

    We report on wide-field imaging of pulsatile microvascular blood flow in the exposed cerebral cortex of a mouse by holographic interferometry. We recorded interferograms of laser light backscattered by the tissue, beating against an off-axis reference beam with a 50 kHz framerate camera. Videos of local Doppler contrasts were rendered numerically by Fresnel transformation and short-time Fourier transform analysis. This approach enabled instantaneous imaging of pulsatile blood flow contrasts in superficial blood vessels over 256 x 256 pixels with a spatial resolution of 10 microns and a temporal resolution of 20 ms.

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

    OpenAIRE

    Vemula, Sateesh Kumar

    2015-01-01

    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...

  18. Pulsatile flow simulator for comparison of cardiac output measurements by electromagnetic flow meter and thermodilution.

    Science.gov (United States)

    Jebson, P J; Karkow, W S

    1986-01-01

    This study examined a pulsatile flow simulator for the purpose of evaluating two measurement devices, an extracorporeal flow probe with an electromagnetic flow meter and several thermodilution catheters. We measured the performance of these devices in a range of low to high flows. Using either saline or blood as a perfusate, we obtained different results with these fluids (p less than 0.001). Each catheter behaved in a linear manner, although variation occurred among the catheters with both saline (minimum slope 1.090, maximum slope 1.190) and blood (minimum slope 1.107, maximum slope 1.154). An increase in rate and stroke volumes of the simulator did not demonstrate an identifiable trend in error. The thermodilution catheters were most accurate at 5.0 L/min irrespective of rate, stroke volume, or perfusate used. In contrast, the electromagnetic flow meter accurately represented flows across the wide range of outputs examined (2.4 to 10.7 L/min). (Slope with saline 1.091, slope with blood 1.080) Throughout the range of flow, the flow meter gave a calibration line 5% higher with blood than with saline. The results indicate that accurate measurement of pulsatile blood flow can be achieved in vitro with an electromagnetic flow meter using saline as a perfusate, provided a correction factor is determined and applied to convert values for saline to accurate values for blood. PMID:2940345

  19. 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. PMID:26983961

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

    International Nuclear Information System (INIS)

    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

  1. Enteric-coating of pulsatile-release HPC capsules prepared by injection molding.

    Science.gov (United States)

    Macchi, E; Zema, L; Maroni, A; Gazzaniga, A; Felton, L A

    2015-04-01

    Capsular devices based on hydroxypropyl cellulose (Klucel® LF) intended for pulsatile release were prepared by injection molding (IM). In the present work, the possibility of exploiting such capsules for the development of colonic delivery systems based on a time-dependent approach was evaluated. For this purpose, it was necessary to demonstrate the ability of molded cores to undergo a coating process and that coated systems yield the desired performance (gastric resistance). Although no information was available on the coating of IM substrates, some issues relevant to that of commercially-available capsules are known. Thus, preliminary studies were conducted on molded disks for screening purposes prior to the spray-coating of HPC capsular cores with Eudragit® L 30 D 55. The ability of the polymeric suspension to wet the substrate, spread, start penetrating and initiate hydration/swelling, as well as to provide a gastroresistant barrier was demonstrated. The coating of prototype HPC capsules was carried out successfully, leading to coated systems with good technological properties and able to withstand the acidic medium with no need for sealing at the cap/body joint. Such systems maintained the original pulsatile release performance after dissolution of the enteric film in pH 6.8 fluid. Therefore, they appeared potentially suitable for the development of a colon delivery platform based on a time-dependent approach. PMID:25585355

  2. In vivo assessment of a new method of pulsatile perfusion based on a centrifugal pump.

    Science.gov (United States)

    Herreros, Jesús; Ubilla, Matías; Berjano, Enrique J; Vila-Nuñez, Juan E; Páramo, José A; Sola, Josu; Mercé, Salvador

    2010-02-01

    The aim of this study was to assess platelet dysfunction and damage to organs after extracorporeal circulation using a pump based on a new method that adds a pulsatile flow to the continuous flow provided by a centrifugal pump. The continuous component of the total flow (2-3 L/min) is created by a Bio-Pump centrifugal pump, while the pulsatile component is created by the pulsating of an inner membrane pneumatically controlled by an intra-aortic counterpulsation balloon console (systolic volume of 37.5 mL in an asynchronous way with a frequency of 60 bpm). Six pigs were subjected to a partial cardiopulmonary bypass lasting 180 min and were sacrificed 60 min after extracorporeal circulation was suspended. The hematological study included the measurement of hematocrit, hemoglobin, leukocytes, and platelet function. The new pump did not significantly alter either platelet count or platelet function. In contrast, hematocrit and hemoglobin were significantly reduced during extracorporeal circulation (approximately 5% P = 0.011, and 2 g/dL P = 0.01, respectively). The leukocyte count during extracorporeal circulation showed a tendency to decrease, but this was not significant. In general, the short-term use of the new pump (4 h) did not cause any serious morphological damage to the heart, lung, kidney, or liver. The results suggest that the hemodynamic performance of the new pump is similar to a conventional centrifugal pump and could therefore be appropriate for use in extracorporeal circulation.

  3. 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.

  4. Elderly depression diagnostic of diabetic patients by brain tissue pulsatility imaging

    Science.gov (United States)

    Hachemi, Mélouka Elkateb; Remeniéras, Jean-pierre; Desmidt, Thomas; Camus, Vincent; Tranquart, François

    2010-01-01

    Pulsatile motion of brain parenchyma results from cardiac and breathing cycles and consists in a rapid displacement in systole, with slow diastolic recovery. Based on the vascular depression concept and recent studies where a correlation was found between cerebral haemodynamics and depression in the elderly, we emitted the hypothesis that tissue brain motion due to perfusion is correlated to elderly depression associated with cardiovascular risk factors. Tissue Pulsatlity Imaging (TPI) is a new ultrasound technique developed firstly at the University of Washington to assess the brain tissue motion. We used TPI technique to measure the brain displacement of two groups of elderly patients with diabetes as a vascular risk factor. The first group is composed of 11 depressed diabetic patients. The second group is composed of 12 diabetic patients without depressive symptoms. Transcranial acquisitions were performed with a 1.8 MHz ultrasound phased array probe through the right temporal bone window. The acquisition of six cardiac cycles was realized on each patient with a frame rate of 23 frames/s. Displacements estimation was performed by off-line analysis. A significant decrease in brain pulsatility was observed in the group of depressed patients compared to the group of non depressed patients. Mean displacement magnitude was about 44±7 μm in the first group and 68±13 μm in the second group.

  5. An approach to the intelligent drug delivery systems: Thermo-responsive membrane for pulsatile drug delivery

    Directory of Open Access Journals (Sweden)

    Evren Atlihan Gundogdu

    2013-09-01

    Full Text Available In this study, the potential use of thermotropic liquid crystals as a responsive release system was investigated. Cholesteryl oleyl carbonate liquid crystal (COC has been embedded in nylon membranes by using vacuum filtration methods. In vitro drug release studies were performed by using a fluid/fluid diffusion cell. Sodium salicylate as a model drug penetration study was performed in nylon membrane with or without COC that is prepared at 25 and 37°C. Also the penetration studies were performed by repeatedly exchanging the temperature cycle (10, 25, 37°C of the water bath at predetermined intervals. It was observed that COC and temperature have effects on the penetration of sodium salicylate. At 37 °C, the penetration rate of sodium salicylate was found higher than 25 °C and 10 °C, respectively. Also, the penetration amount of sodium salicylate has changed as pulsatile drug delivery in the presence of COC. As a result, according to the patients’ requirements, it seems that the penetration rate and profile can be adjusted by developing pulsatile drug delivery as a new system.

  6. Flow dynamics in anatomical models of abdominal aortic aneurysms: computational analysis of pulsatile flow.

    Science.gov (United States)

    Finol, Ender A; Amon, Cristina H

    2003-01-01

    Blood flow in human arteries is dominated by time-dependent transport phenomena. In particular, in the abdominal segment of the aorta under a patient's average resting conditions, blood exhibits laminar flow patterns that are influenced by secondary flows induced by adjacent branches and in irregular vessel geometries. The flow dynamics becomes more complex when there is a pathological condition that causes changes in the normal structural composition of the vessel wall, for example, in the presence of an aneurysm. An aneurysm is an irreversible dilation of a blood vessel accompanied by weakening of the vessel wall. This work examines the importance of hemodynamics in the characterization of pulsatile blood flow patterns in individual Abdominal Aortic Aneurysm (AAA) models. These patient-specific computational models have been developed for the numerical simulation of the momentum transport equations utilizing the Finite Element Method (FEM) for the spatial and temporal discretization. We characterize pulsatile flow dynamics in AAAs for average resting conditions by means of identifying regions of disturbed flow and quantifying the disturbance by evaluating wall pressure and wall shear stresses at the aneurysm wall. PMID:14515766

  7. Design and in vitro evaluation of compression-coated pulsatile release tablets of losartan potassium

    Directory of Open Access Journals (Sweden)

    M Bajpai

    2012-01-01

    Full Text Available In majority of individuals blood pressure rises in the early morning hours, which lead to serious cardiovascular complications. Formulation of pulsatile system makes it possible to deliver drug at definite period of time when symptoms of the disease condition are most critical. The purpose of the present work was to develop pulsatile release tablet of losartan potassium for chronotherapy in hypertension. The prepared system consisted of a core tablet coated with versatile and safe hydrophilic cellulosic ethers such as, hydroxypropyl methylcellulose, hydroxypropyl cellulose and sodium carboxy methylcellulose to produce burst release after predetermined lag time. Various formulation factors were studied through series of test and in vitro dissolution study. It was found that core tablets containing superdisintegrant failed to produce burst drug release pattern while effervescent agent was able to do so. Results also reveal that coating composition and coating level affects lag time. Formulation containing effervescent agent in core and coated with 200 mg hydroxypropyl cellulose provide lag time of 4.5 h with 73% drug release in 6 h that followed a sigmoidal release pattern. These values were close to the desired objective of producing lag time of 5-6 h followed by fast drug release. This approach can thus provide a useful means for timed release of losartan and is helpful for patients with morning surge.

  8. Observation of the CSF pulsatile flow in an aqueduct using cine MRI with presaturation bolus tracking, (2); The classification of pulsatile-flow patterns in adult patients with ventriculomegaly

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, Satoshi; Akada, Shouhiro; Deguchi, Itaru; Miwa, Tetsurou; Itoh, Hiroshi (Tokyo Medical Coll. (Japan))

    1991-12-01

    Various to-and-fro motion patterns of the CSF flow in an aqueduct were analyzed in ten normal volunteers, in ten patients with secondary normal-pressure hydrocephalus, in nine patients with idiopathic ventriculomegaly, and in five cases of brain atrophy using cine MRI with presaturation bolus tracking. The to-and-fro motion patterns were classified into four types. Type I; in which the velocity of the CSF in the aqueduct is slower than 15 mm/sec, and the duration of the flow in the caudal direction is longer than in the rostral. Type II; in which the velocity of the CSF in the aqueduct is faster than 15 mm/sec, and the duration of the flow in the caudal direction is longer than in the rostral. Type III; in which the velocity is relatively faster than Type I, but the duration of the flow in the caudal direction is shorter than in the rostral. Type IV; in which the velocity is slower than 15 mm/sec, and the duration of the flow in the caudal direction is shorter than in the rostral. In secondary normal-pressure hydrocephalus (NPH), the flow patterns were all of Type II. In idiopathic ventriculomegaly, the cases of which showed ventricular reflux on RI-cisternography, the flow patterns were divided into three types (II, III and IV). In the cases of brain atrophy, who did not show ventricular reflux on RI-cisternography, the flow patterns were all of Type I. We conclude that the evaluation of the CSF pulsatile flow in the aqueduct can give new clinical information for use in investigating the pathogenesis of the ventriculomegaly. (author).

  9. Hormone Health Network

    Science.gov (United States)

    ... Cuidadores Hormones and Health Journey Through the Endocrine System Endocrine Disrupting Chemicals (EDCs) Endocrine Glands and Types of ... Health Hormones and Health Journey Through the Endocrine System Endocrine Disrupting Chemicals (EDCs) Endocrine Glands and Types of ...

  10. Hormones and Obesity

    Science.gov (United States)

    ... Balance › Hormones and Obesity Fact Sheet Hormones and Obesity March, 2010 Download PDFs English Espanol Editors Caroline Apovian, MD Judith Korner, MD, PhD What is obesity? Obesity is a chronic (long-term) medical problem ...

  11. Menopause and Hormones

    Science.gov (United States)

    ... Consumer Information by Audience For Women Menopause and Hormones: Common Questions Share Tweet Linkedin Pin it More ... reproduction and distribution. Learn More about Menopause and Hormones Menopause--Medicines to Help You Links to other ...

  12. Hormones and Hypertension

    Science.gov (United States)

    Fact Sheet Hormones and Hypertension What is hypertension? Hypertension, or chronic (long-term) high blood pressure, is a main cause of ... tobacco, alcohol, and certain medications play a part. Hormones made in the kidneys and in blood vessels ...

  13. Hormone therapy in acne

    OpenAIRE

    Chembolli Lakshmi

    2013-01-01

    Underlying hormone imbalances may render acne unresponsive to conventional therapy. Relevant investigations followed by initiation of hormonal therapy in combination with regular anti-acne therapy may be necessary if signs of hyperandrogenism are present. In addition to other factors, androgen-stimulated sebum production plays an important role in the pathophysiology of acne in women. Sebum production is also regulated by other hormones, including estrogens, growth hormone, insulin, insulin-l...

  14. Lattice-Boltzmann simulation for bubble pulsatile flow in capillary tube%毛细管内多相脉动流动的格子-Boltzmann模拟

    Institute of Scientific and Technical Information of China (English)

    马强; 张莹; 曾建邦; 韩婧潇; 贾国瑞

    2011-01-01

    基于伪势模型理论,建立毛细管内汽液两相工质脉动流动的等温格子-Boltzmann模型.将利用该模型取得的静态液滴形态以及表面张力、大空间和窄空间内气泡浮升运动时的形态模拟结果与文献的研究结果进行对比,验证了模型的可靠性.对毛细管内泡状流和柱塞流两种流型在边界正弦压力波作用下绝热脉动流动情况进行了数值模拟.通过模拟研究了毛细管内不同压力波振幅下液相Reynolds数和气泡位移幅度周期性变化规律;获得了汽液界面形态在脉动过程中的变化;观察到在边界液相速度方向发生改变时,边界附近区域的Reynolds数振荡现象;分析了重力对脉动运动过程的影响.模拟结果为分析以毛细管为主要构件的脉动热管内汽液两相工质的工作过程提供了一定依据.%Based on the theory of pseudo-potential, an isothermal lattice-Boltzmann model for multiphase pulsatile flow in capillary tube was established. By selecting the appropriate dimensionless parameters, the simulation unit was loaded into an actual unit. Simulation results obtained by this model, such as surface tension of static drop, shape of rising bubble in large space and narrow space, were compared with theory and other scholars' research results, and the reliability of this model was verified. Bubbly flow driven by the sinusoidal pressure wave in capillary tube was simulated. The relationship between pressure wave amplitude and periodic variation of liquid phase Re number and bubble displacement was investigated. Shape changes of vapor-liquid interface in the periodic pulsatile process was obtained. The oscillation of Re number near the boundary area was observed when the direction of liquid velocity on the boundary was changed. The reason for this phenomenon was discussed in this paper. The effect of gravity on the pulsatile process was analyzed. Simulation results validated the empirical law that the flow

  15. Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model

    NARCIS (Netherlands)

    P. Symersky; R.P.J. Budde; P. Westers; B.A.J.M. de Mol; M. Prokop

    2011-01-01

    Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. A Medtronic Hall ti

  16. Clinical Effectiveness of Centrifugal Pump to Produce Pulsatile Flow During Cardiopulmonary Bypass in Patients Undergoing Cardiac Surgery

    NARCIS (Netherlands)

    Gu, Y. John; van Oeveren, Willem; Mungroop, Hubert E.; Epema, Anne H.; den Hamer, Inez J.; Keizer, Jorrit J.; Leuvenink, Ron P.; Mariani, Massimo A.; Rakhorst, Gerhard

    2011-01-01

    Although the centrifugal pump has been widely used as a nonpulsatile pump for cardiopulmonary bypass (CPB), little is known about its performance as a pulsatile pump for CPB, especially on its efficacy in producing hemodynamic energy and its clinical effectiveness. We performed a study to evaluate w

  17. Multidetector CT imaging of mechanical prosthetic heart valves : quantification of artifacts with a pulsatile in-vitro model

    NARCIS (Netherlands)

    Symersky, Petr; Budde, Ricardo P. J.; Westers, Paul; de Mol, Bas A. J. M.; Prokop, Mathias

    2011-01-01

    Objectives Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. Methods

  18. Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model

    NARCIS (Netherlands)

    Symersky, P.; Budde, R.P.; Westers, P.; Mol, B.A. de; Prokop, M.

    2011-01-01

    OBJECTIVES: Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. METHODS

  19. 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...

  20. 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 dis

  1. First-trimester measurement of the ductus venosus pulsatility index and the prediction of congenital heart defects

    NARCIS (Netherlands)

    Timmerman, E.; Clur, S. A.; Pajkrt, E.; Bilardo, C. M.

    2010-01-01

    Objective This study was carried out to evaluate the additional predictive value of ductus venosus pulsatility index for veins (DV-PIV) in the identification of congenital heart defects (CHDs) in fetuses with an enlarged nuchal translucency (NT) and a normal karyotype. Methods All chromosomally norm

  2. Hormones, genes, and behavior

    OpenAIRE

    Pfaff, Donald W.

    1997-01-01

    With assays of hormone-sensitive behaviors, it is possible to demonstrate both direct and indirect actions of genes on mammalian social behaviors. Direct effects of estrogen receptor gene expression and progesterone receptor gene expression figure prominently in well analyzed neuroendocrine mechanisms for sex behavior, operating through a neural circuit that has been delineated. Indirect effects, notably the consequences of sexual differentiation, display complex d...

  3. Hormonal therapies in acne.

    Science.gov (United States)

    Shaw, James C

    2002-07-01

    Hormones, in particular androgen hormones, are the main cause of acne in men, women, children and adults, in both normal states and endocrine disorders. Therefore, the use of hormonal therapies in acne is rational in concept and gratifying in practice. Although non-hormonal therapies enjoy wide usage and continue to be developed, there is a solid place for hormonal approaches in women with acne, especially adult women with persistent acne. This review covers the physiological basis for hormonal influence in acne, the treatments that are in use today and those that show promise for the future. The main treatments to be discussed are oral contraceptives androgen receptor blockers like spironolactone and flutamide, inhibitors of the enzyme 5 alpha-reductase and topical hormonal treatments. PMID:12083987

  4. 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.

  5. 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. PMID:26017285

  6. Estimation of pressure gradients in pulsatile flow from magnetic resonance acceleration measurements.

    Science.gov (United States)

    Tasu, J P; Mousseaux, E; Delouche, A; Oddou, C; Jolivet, O; Bittoun, J

    2000-07-01

    A method for estimating pressure gradients from MR images is demonstrated. Making the usual assumption that the flowing medium is a Newtonian fluid, and with appropriate boundary conditions, the inertial forces (or acceleration components of the flow) are proportional to the pressure gradients. The technique shown here is based on an evaluation of the inertial forces from Fourier acceleration encoding. This method provides a direct measurement of the total acceleration defined as the sum of the velocity derivative vs. time and the convective acceleration. The technique was experimentally validated by comparing MR and manometer pressure gradient measurements obtained in a pulsatile flow phantom. The results indicate that the MR determination of pressure gradients from an acceleration measurement is feasible with a good correlation with the true measurements (r = 0.97). The feasibility of the method is demonstrated in the aorta of a normal volunteer. Magn Reson Med 44:66-72, 2000. PMID:10893523

  7. Arterial pulsatility as an index of cerebral microangiopathy in diabetes type 2.

    Science.gov (United States)

    Agha, M S; Alboudi, A

    2014-01-09

    Transcranial doppler is an inexpensive, non-invasive investigation. This study assessed its validity in determining cerebral small vessel disease in patients with type 2 diabetes mellitus. Flow velocity and pulsatility index were measured in the middle cerebral, basilar and intracranial internal carotid arteries of a sample of 141 diabetic patients with no other risk factors, and 132 age- and sex-matched healthy controls. The patients were divided into 2 groups: 73 with complicated and 68 with uncomplicated diabetes. There was a statistically significant difference between the complicated diabetes and control groups for the 3 arteries and most indices. The differences between the uncomplicated diabetes patients and the controls were also statistically significant but less strongly. Transcranial doppler may be useful in early diagnosis of cerebral small vessel disease in patients with type 2 diabetes mellitus.

  8. Non-invasive Estimation of Pressure Gradients in Pulsatile Flow using Ultrasound

    DEFF Research Database (Denmark)

    Olesen, Jacob Bjerring; Villagómez Hoyos, Carlos Armando; Traberg, Marie Sand;

    2014-01-01

    This paper investigates how pressure gradients in a pulsatile flow environment can be measured non-invasively using ultrasound. The presented set-up is based on vector velocity fields measured on a blood mimicking fluid moving at a peak flow rate of 1 ml/s through a constricted vessel. Fields...... of pressure gradients are calculated using the Navier-Stokes equations. Flow data are acquired to a depth of 3 cm using directional synthetic aperture flow imaging on a linear array transducer producing 1500 image frames of velocity estimates per second. Scans of a carotid bifurcation phantom with a 70......% constriction are performed using an experimental scanner. The performance of the presented estimator is evaluated by comparing its results to a numerical simulation model, which geometry is reconstructed from MRI data. The study showed pressure gradients varying from 0 kPa/m to 4.5 kPa/m with a maximum bias...

  9. Development and Evaluation of Dual Cross-Linked Pulsatile Beads for Chronotherapy of Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Abanesh kumar Bansal

    2013-01-01

    Full Text Available In the present investigation, pulsatile release beads were prepared by ionic gelation technique. Lornoxicam dual cross-linked beads were prepared by dropping dispersed phase of lornoxicam, pectin, and sodium alginate into the dispersion phase of different concentrations of calcium chloride solution followed by aluminium chloride solution. The formulated beads were further coated by Eudragit L & S 100 in the ratio 1 : 2 w/w in order to achieve desired lag time. In vitro release study showed lag time of 5–8 h before release of lornoxicam from the formulated beads. Thus, formulated dual cross-linked beads when administered at bed time may release lornoxicam when needed most for chronotherapeutics of early morning rheumatoid arthritis attacks in chronic patients.

  10. Hormones and the pilosebaceous unit

    OpenAIRE

    Chen, Wen-Chieh; Zouboulis, Christos C

    2009-01-01

    Hormones can exert their actions through endocrine, paracrine, juxtacrine, autocrine and intracrine pathways. The skin, especially the pilosebaceous unit, can be regarded as an endocrine organ meanwhile a target of hormones, because it synthesizes miscellaneous hormones and expresses diverse hormone receptors. Over the past decade, steroid hormones, phospholipid hormones, retinoids and nuclear receptor ligands as well as the so-called stress hormones have been demonstrated to play pivotal rol...

  11. Hormonal therapy for acne.

    Science.gov (United States)

    George, Rosalyn; Clarke, Shari; Thiboutot, Diane

    2008-09-01

    Acne affects more than 40 million people, of which more than half are women older than 25 years of age. These women frequently fail traditional therapy and have high relapse rates even after isotretinoin. Recent advances in research have helped to delineate the important role hormones play in the pathogenesis of acne. Androgens such as dihydrotestosterone and testosterone, the adrenal precursor dehydroepiandrosterone sulfate, estrogens, growth hormone, and insulin-like growth factors may all contribute to the development of acne. Hormonal therapy remains an important part of the arsenal of acne treatments available to the clinician. Women dealing with acne, even those without increased serum androgens, may benefit from hormonal treatments. The mainstays of hormonal therapy include oral contraceptives and antiandrogens such as spironolactone, cyproterone acetate, or flutamide. In this article, we discuss the effects of hormones on the pathogenesis of acne, evaluation of women with suspected endocrine abnormalities, and the myriad of treatment options available. PMID:18786497

  12. Hormones and endometrial carcinogenesis.

    Science.gov (United States)

    Kamal, Areege; Tempest, Nicola; Parkes, Christina; Alnafakh, Rafah; Makrydima, Sofia; Adishesh, Meera; Hapangama, Dharani K

    2016-02-01

    Endometrial cancer (EC) is the commonest gynaecological cancer in the Western World with an alarmingly increasing incidence related to longevity and obesity. Ovarian hormones regulate normal human endometrial cell proliferation, regeneration and function therefore are implicated in endometrial carcinogenesis directly or via influencing other hormones and metabolic pathways. Although the role of unopposed oestrogen in the pathogenesis of EC has received considerable attention, the emerging role of other hormones in this process, such as androgens and gonadotropin-releasing hormones (GnRH) is less well recognised. This review aims to consolidate the current knowledge of the involvement of the three main endogenous ovarian hormones (oestrogens, progesterone and androgens) as well as the other hormones in endometrial carcinogenesis, to identify important avenues for future research. PMID:26966933

  13. Need for Comprehensive Hormonal Workup in the Management of Adrenocortical Tumors in Children

    OpenAIRE

    Gönç, E. Nazlı; Özön, Zeynep Alev; Çakır, Meltem Didem; Alikaşifoğlu, Ayfer; Kandemir, Nurgün

    2014-01-01

    Ob­jec­ti­ve: Clinical findings do not reflect the excess hormonal status in adrenocortical tumors (ACTs) in children. Identification of abnormal hormone secretion may help provide the tumor marker and delineate those patients with a risk of adrenal suppression following tumor removal. To analyze the impact of complete hormonal assessment regardless of the clinical presentation in hormone-secreting ACTs in childhood. Methods: Association of hormonal workup at diagnosis with the clinical findi...

  14. Adult growth hormone deficiency

    OpenAIRE

    Vishal Gupta

    2011-01-01

    Adult growth hormone deficiency (AGHD) is being recognized increasingly and has been thought to be associated with premature mortality. Pituitary tumors are the commonest cause for AGHD. Growth hormone deficiency (GHD) has been associated with neuropsychiatric-cognitive, cardiovascular, neuromuscular, metabolic, and skeletal abnormalities. Most of these can be reversed with growth hormone therapy. The insulin tolerance test still remains the gold standard dynamic test to diagnose AGHD. Growth...

  15. Modelling plant hormone gradients.

    OpenAIRE

    S. Moore; Zhang, X.; Liu, J; Lindsey, K.

    2015-01-01

    Cellular patterning in the Arabidopsis root is coordinated via a localised auxin concentration maximum in the root tip, requiring the regulated expression of specific genes. The activities of plant hormones such as auxin, ethylene and cytokinin depend on cellular context and exhibit either synergistic or antagonistic interactions. Due to the complexity and nonlinearity of spatiotemporal interactions between both hormones and gene expression in root development, modelling plant hormone gradien...

  16. MR imaging of pulsatile CSF movement in hydrocephalus communicans before and after CSF shunt implantation. Magnetresonanztomographische Darstellung der Liquorpulsbewegung bei Hydrozephalus communicans vor und nach Shuntanlage

    Energy Technology Data Exchange (ETDEWEB)

    Goldmann, A. (Abt. Radiologie 1, Ulm Univ. (Germany)); Kunz, U. (Abt. Neurochirurgie, Bundeswehrkrankenhaus Ulm (Germany)); Rotermund, F. (Abt. Neurochirurgie, Bundeswehrkrankenhaus Ulm (Germany)); Friedrich, J.M. (Abt. Radiologie 1, Ulm Univ. (Germany)); Schnarkowski, P. (Abt. Radiologie 1, Ulm Univ. (Germany))

    1992-12-01

    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.)

  17. 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.

  18. Pulsatile blood flow in large arteries:comparative study of Burton’s and McDonald’s models

    Institute of Scientific and Technical Information of China (English)

    K.GAYATHRI; K.SHAILENDHRA

    2014-01-01

    To get a clear picture of the pulsatile nature of blood flow and its role in the pathogenesis of atherosclerosis, a comparative study of blood flow in large arteries is carried out using the two widely used models, McDonald’s and Burton’s models, for the pressure gradient. For both models, the blood velocity in the lumen is obtained analytically. Elaborate investigations on the wall shear stress (WSS) and oscillatory shear index (OSI) are carried out. The results are in good agreement with the available data in the literature. The superiority of McDonald’s model in capturing the pulsatile nature of blood flow, especially the OSI, is highlighted. The present investigation supports the hypothesis that not only WSS but also OSI are the essential features determining the pathogenesis of atherosclerosis. Finally, by reviewing the limitations of the present investigation, the possibility of improvement is explored.

  19. 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;

    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....... Department of Clinical Medicine, Aalborg University Hospital, Aalborg, Denmark. 5. Department of Pathology, Aalborg University Hospital, Aalborg, Denmark. 6. Department of Obstetrics and Gynecology, Aarhus University Hospital Skejby, Skejby, Denmark. ABSTRACT BODY: Objectives: The Magnetic Resonance Imaging...... (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...

  20. Effects of growth hormone administration on the body composition and hormone levels of genetically fat sheep

    International Nuclear Information System (INIS)

    Coopworth sheep selected for low (lean) or high (fat) backfat have large differences in plasma GH profiles. Fat genotype ram lambs (5 months old) were treated with growth hormone (GH) to simulate the plasma GH profiles of lean sheep and investigate whether exogenous GH could modify carcass fatness. For 77 days, bovine GH was administered at 25mug/kg live weight per day either as a single, daily subcutaneous bolus (fat bolus) or via portable pulsatile infusion pumps (fat pump) which delivered GH solution at 90-min intervals into a jugular catheter. Measurements of body composition were made by computed tomography (CT) and ultrasonic scanning during the trial, with linear carcass measurements and proximate analysis undertaken at the end of the experiment. Before treatments began, mean plasma GH levels were lower (P < 0.01) in fat control (0.34 mug/l) than in lean lambs (1.1 mug/l). Several weeks after the start of the trial, mean plasma GH had increased in both fat bolus (1.2mug/l) and fat pump (0.45mug/l) treatment lambs with major changes in the pulsatility relative to the fat control lambs. Although these changes were maintained in the fat bolus lambs, by the end of the trial there was no significant difference in mean plasma GH between fat pump and fat control sheep. Throughout the trial, plasma IGF-1 levels were higher in fat bolus, fat pump and lean lambs than in fat control lambs. Analysis of body composition data over the GH treatment period revealed that the slope of the allometric equation for total fat relative to empty body weight was lower in the fat bolus lambs (1.07) than in the lean lambs (1.50) with fat control and fat pump treatment lambs intermediate (1.30 and 1.36, respectively). Subcutaneous fat was later maturing in lean lambs than in fat control and bolus treatment lambs when regressed against total fat, with the fat pump treatment lambs being intermediate. Linear carcass measurements revealed changes due to GH administration in the

  1. Plant Hormone Binding Sites

    OpenAIRE

    Napier, Richard

    2004-01-01

    • Aims Receptors for plant hormones are becoming identified with increasing rapidity, although a frustrating number remain unknown. There have also been many more hormone‐binding proteins described than receptors. This Botanical Briefing summarizes what has been discovered about hormone binding sites, their discovery and descriptions, and will not dwell on receptor functions or activities except where these are relevant to understand binding.

  2. Hemostatic Disorders in Hormonally Active Pituitary Tumors.

    Science.gov (United States)

    Świątkowska-Stodulska, R; Babińska, A; Mital, A; Stodulski, D; Sworczak, K

    2015-10-01

    Endocrinopathies encompass heterogeneous diseases that can lead to hemostasis disorders at various stages over their clinical course. Normal hemostasis requires an equilibrium between the processes of coagulation and fibrinolysis, which depend on multiple activators and inhibitors. To date, the influence of various hormonal disorders on the hemostatic system has been assessed many times. The aim of this review was to analyze hemostasis abnormalities that occur in patients with hormonally active pituitary tumors: corticotropinoma, somatotropinoma, prolactinoma, gonadotropinoma and thyrotropinoma. Authors discuss studies that examined coagulation and hemostasis parameters among patients with these tumors, as well as analyze antithrombotic prophylaxis approach for endogenous hypercortisolemia subjects in particular. PMID:26285071

  3. Surgical treatment of severe chronic venous insufficiency caused by pulsatile varicose veins in a patient with tricuspid regurgitation.

    Science.gov (United States)

    Casian, D; Gutsu, E; Culiuc, V

    2009-04-01

    A case of severe chronic venous insufficiency caused by pulsatile varicose veins in a 46-year-old man with tricuspid regurgitation is presented. Active venous leg ulcer complicated with recurrent venous bleeding and inefficacy of conservative management serve as indications for surgical treatment. This case demonstrates the possibility of radical surgical correction of pathological venous reflux by means of saphenofemoral ligation, foam sclerotherapy and subfascial endoscopic perforator surgery.

  4. Particle Image Velocimetry Study of Pulsatile Flow in Bi-leaflet Mechanical Heart Valves with Image Compensation Method

    OpenAIRE

    Shi, Yubing; Yeo, Tony Joon Hock; Zhao, Yong; Hwang, Ned H. C.

    2006-01-01

    Particle Image Velocimetry (PIV) is an important technique in studying blood flow in heart valves. Previous PIV studies of flow around prosthetic heart valves had different research concentrations, and thus never provided the physical flow field pictures in a complete heart cycle, which compromised their pertinence for a better understanding of the valvular mechanism. In this study, a digital PIV (DPIV) investigation was carried out with improved accuracy, to analyse the pulsatile flow field ...

  5. Osteoblasts respond to pulsatile fluid flow with short-term increases in PGE(2) but no change in mineralization

    Science.gov (United States)

    Nauman, E. A.; Satcher, R. L.; Keaveny, T. M.; Halloran, B. P.; Bikle, D. D.

    2001-01-01

    Although there is no consensus as to the precise nature of the mechanostimulatory signals imparted to the bone cells during remodeling, it has been postulated that deformation-induced fluid flow plays a role in the mechanotransduction pathway. In vitro, osteoblasts respond to fluid shear stress with an increase in PGE(2) production; however, the long-term effects of fluid shear stress on cell proliferation and differentiation have not been examined. The goal of this study was to apply continuous pulsatile fluid shear stresses to osteoblasts and determine whether the initial production of PGE(2) is associated with long-term biochemical changes. The acute response of bone cells to a pulsatile fluid shear stress (0.6 +/- 0.5 Pa, 3.0 Hz) was characterized by a transient fourfold increase in PGE(2) production. After 7 days of static culture (0 dyn/cm(2)) or low (0.06 +/- 0.05 Pa, 0.3 Hz) or high (0.6 +/- 0.5 Pa, 3.0 Hz) levels of pulsatile fluid shear stress, the bone cells responded with an 83% average increase in cell number, but no statistical difference (P > 0.53) between the groups was observed. Alkaline phosphatase activity per cell decreased in the static cultures but not in the low- or high-flow groups. Mineralization was also unaffected by the different levels of applied shear stress. Our results indicate that short-term changes in PGE(2) levels caused by pulsatile fluid flow are not associated with long-term changes in proliferation or mineralization of bone cells.

  6. Evaluation of growth hormone release and human growth hormone treatment in children with cranial irradiation-associated short stature

    International Nuclear Information System (INIS)

    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

  7. Luteinizing hormone (LH) blood test

    Science.gov (United States)

    ICSH - blood test; Luteinizing hormone - blood test; Interstitial cell stimulating hormone - blood test ... medicines you take. These include: Birth control pills Hormone therapy Testosterone DHEA (a supplement) If you are ...

  8. Aging changes in hormone production

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/004000.htm Aging changes in hormone production To use the sharing ... that produce hormones are controlled by other hormones. Aging also changes this process. For example, an endocrine ...

  9. Hormone therapy for prostate cancer

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000908.htm Hormone therapy for prostate cancer To use the sharing ... helps slow the growth of prostate cancer. Male Hormones and Prostate Cancer Androgens are male sex hormones. ...

  10. The Aging Male Hypothalamic-Pituitary-Gonadal Axis: pulsatility and feedback

    OpenAIRE

    Veldhuis, Johannes D.; Keenan, Daniel M.; Liu, Peter Y.; Iranmanesh, Ali; Takahashi, Paul Y; Nehra, Ajay X.

    2008-01-01

    Aging results in insidious decremental changes in hypothalamic, pituitary and gonadal function. The foregoing three main anatomic loci of control are regulated by intermittent time-delayed signal exchange, principally via gonadotropin-releasing hormone (GnRH), luteinizing hormone (LH) and testosterone/estradiol (Te/E2). A mathematical framework is required to embody these dynamics. The present review highlights integrative adaptations in the aging male hypothalamic-pituitary-gonadal axis, as ...

  11. Graphical User Interface (GUI In MatLab for Solving The Pulsatile Flow in Blood Vessel

    Directory of Open Access Journals (Sweden)

    badreddin giuma elghariani

    2009-08-01

    Full Text Available

    Abstract

     

    Blood flow analysis is a study of measuring the blood pressure and finding its equivalent flow rate, velocity profile and wall shear stress. In this article, we determined the relationship between blood pressure gradient, velocity profile, centerline velocity, volumetric flow rate and wall shear stress analytically  through a Graphical User Interface (GUI. If one of these time-dependent blood flow properties is known, i.e. pressure gradient, velocity profile, volumetric flow rate or wall shear stress, then the remaining properties can be calculated. We developed a code to solve these blood flow properties. Any time-dependent blood properties can be used as  input data. These data are then digitized and saved in our code. Subsequently, these data are curve-fitted using the Fourier series. The corresponding coefficients of Fourier series are then used to calculate the blood property. Once this is obtained, the remaining three other flow properties can be subsequently calculated. This GUI serves as a learning tool for  students who wish to pursue his/her knowledge in understanding the relationship of various blood flow properties of pulsatile blood flow as well as the mathematics governing pulsatile flows.

  12. [Preliminary study of a new heart valve prostheses implanted with minimally invasive techniques: pulsatile-flow testing in vitro].

    Science.gov (United States)

    Tang, Jinglong; Wang, Shuo; Liu, Li; Wang, Jian; Wang, Chunren

    2013-02-01

    The aim of this study was to investigate the pulsatile-flow performance in vitro of a new heart valve prostheses implanted with minimally invasive techniques (HVPMIT). Three HVPMITs were tested valves and another three original biological heart valve prostheses acted as reference valves. The pulsatile-flow parameters (including mean pressure drop, regurgitant percentage of stroke volume, and effective orifice area) were tested in a pulse duplicator according to the methods listed in ISO5840-2005 and GB 12279-2008. The results demonstrated that the regurgitant percentage of stroke volume of tested valves was up to 13%. It was significantly higher than that of the reference valves. This result suggested that paravalvular leakage had occurred in the tested valves. It was found in the further analysis that because HVPMIT was not sewn into the heart tissue when the HVPMIT was implanted in vivo and there was not a sewing ring in the HVPMIT, when tested valves were fixed in the pulse duplicator, some gaps might exist between the stent of HVPMIT and the fix gasket, and the paravalvular leakage could therefore take place through these gaps. This study demonstrated that there are significant differences in the shape, structure, fixation in vivo and clinical operational methods between HVPMIT and original biological heart valve prostheses. It is necessary to establish new test methods which adapt for HVPMIT to evaluate its pulsatile-flow performance according to its own features. PMID:23488159

  13. Pulsatile dynamic stiffness of cartilage-like materials and use of agarose gels to validate mechanical methods and models.

    Science.gov (United States)

    Scandiucci de Freitas, P; Wirz, D; Stolz, M; Göpfert, B; Friederich, N-F; Daniels, A U

    2006-08-01

    Stiffness is a fundamental indicator of the functional state of articular cartilage. Reported test modes include compressive incremental strain to determine the equilibrium modulus, and sinusoidal strain to determine the dynamic modulus and stress/strain loss angle. Here, initial development is described for a method recognizing that gait is pulsatile. Agarose gels have been used by others for validation or comparison of mechanical test methods and models for cartilage and proteoglycan aggregate. Accordingly, gels ranging from 0.5 to 20% agarose were prepared. Pulsatile stiffness in both indentation and unconfined compression were closely reproducible. Stiffness as a function of agarose concentration rose exponentially, as found using other methods. Indentation stiffness was higher than for unconfined compression and ranged from approximately 2.0 kPa for 0.5% gel to approximately 3,800 kPa for 20% gel. Pulsatile dynamic stiffness appears to be a useful method, although further development is needed. Agarose gel stiffness values obtained by other methods were reviewed for comparison. Unfortunately, reported values for a given agarose concentration ranged widely (e.g. fourfold) even when test methods were similar. Causes appear to include differences in molecular weight and gel preparation time-temperature regimens. Also, agarose is hygroscopic, leading to unintended variations in gel composition. Agarose gels are problematic materials for validation or comparison of cartilage mechanical test methods and models. PMID:16470817

  14. Hormones and female sexuality

    Directory of Open Access Journals (Sweden)

    Bjelica Artur L.

    2003-01-01

    Full Text Available Introduction In contrast to animal species in which linear relationships exist between hormonal status and sexual behaviour sexuality in human population is not determined so simply by the level of sexual steroids. The article analyses female sexuality in the light of hormonal status. Administration of sexual steroids during pregnancy and sexual differentiation High doses of gestagens, especially those with high androgen activity, widely used against miscarriages may lead to tomboys, but without differences in sexual orientation. However, it has been observed that the frequency of bisexual and lesbian women is higher in women with congenital adrenogenital syndrome. Hormones sexual desire and sexuality during menstrual cycle It has been established that sexual desire, autoeroticism and sexual fantasies in women depend on androgen levels. There are a lot of reports claiming that sexual desire varies during the menstrual cycle. Hormonal contraception and sexuality Most patients using birth control pills present with decreased libido. But, there are reports that progestagens with antiandrogenic effect in contraceptive pills do not affect sexual desire. Hormonal changes in peri- and postmenopausal period and sexuality Decreased levels of estrogen and testosterone in older women are associated with decreased libido, sensitivity and erotic stimuli. Sexuality and hormone replacement therapy Hormonal therapy with estrogen is efficient in reference to genital atrophy, but not to sexual desire. Really increased libido is achieved using androgens. Also, therapy with dehydroepiandrosterone (DHEA and tibolone have positive effects on female libido. Conclusion Effect of sexual steroids on sexual sphere of women is very complex. The association between hormones and sexuality is multidimensional, as several hormones are important in regulation of sexual behaviour. Still, it should be pointed out that sexuality is in the domain of hormonal, emotional

  15. Experiment K-7-22: Growth Hormone Regulation Synthesis and Secretion in Microgravity. Part 3; Plasma Analysis Hormone Measurements

    Science.gov (United States)

    Grindeland, R. E.; Popova, I. A.; Grossman, E.; Rudolph, I.

    1994-01-01

    Plasma from space flight and tail suspended rats was analyzed for a number of constituents in order to evaluate their metabolic status and endocrine function. The data presented here cover plasma hormone measurements. Corticosterone, thyroxine, and testosterone were measured by radioimmunoassay. Prolactin and growth hormone were measured by double antibody immunoassays using hormones and antisera prepared in house. Data were evaluated by analysis of variance.

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

    International Nuclear Information System (INIS)

    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)

  17. 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

    shear stress, producing a constant laminar flow (generating a shear stress of 6 dyne/cm(2)), laminar pulsatile atheroprotective flow (with a mean shear stress of 20 dyne/cm(2)), or laminar atheroprone bidirectional flow (with a mean shear stress of 0 dyne/cm(2)) differentially induced TRPC6 and TRPV1 m......RNA as measured by quantitative real-time RT-PCR and normalized to GAPDH expression. Thereby, TRPC6 and TRPV1 mRNA expressions were significantly increased after 24 hours of exposure to an atheroprone flow profile compared with an atheroprotective flow profile. Furthermore, the expression of transcription factors...... GATA1 and GATA4 was significantly correlated with the expression of TRPC6 mRNA. In contrast, after 24 hours of constant laminar flow, the expression of TRPC6 and TRPV1 mRNA was unchanged, whereas the expression of TRPC3 and TRPM7 was significantly higher in endothelial cells exposed to shear stress...

  18. In vitro Doppler ultrasound investigation of turbulence intensity in pulsatile flow with simulated cardiac variability.

    Science.gov (United States)

    Thorne, Meghan L; Poepping, Tamie L; Nikolov, Hristo N; Rankin, Richard N; Steinman, David A; Holdsworth, David W

    2009-01-01

    An in vitro investigation of turbulence intensity (TI) associated with a severe carotid stenosis in the presence of physiological cardiac variability is described. The objective of this investigation was to determine if fluctuations due to turbulence could be quantified with conventional Doppler ultrasound (DUS) in the presence of normal physiological cycle-to-cycle cardiac variability. An anthropomorphic model of a 70% stenosed carotid bifurcation was used in combination with a programmable flow pump to generate pulsatile flow with a mean flow rate of 6 mL/s. Utilizing the pump, we studied normal, nonrepetitive cycle-to-cycle cardiac variability (+/-3.9%) in flow, as well as waveform shapes with standard deviations equal to 0, 2 and 3 times the normal variation. Eighty cardiac cycles of Doppler data were acquired at two regions within the model, representing either laminar or turbulent flow; each measurement was repeated six times. Turbulence intensity values were found to be 11 times higher (p laminar region, with a mean difference of 24 cm/s. Twenty cardiac cycles were required for confidence in TI values. In conclusion, these results indicate that it is possible to quantify TI in vitro, even in the presence of normal and exaggerated cycle-to-cycle cardiac variability.

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

    Science.gov (United States)

    Shit, G. C.; Majee, Sreeparna

    2015-08-01

    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.

  20. A Pulsatile Bioreactor for Conditioning of Tissue-Engineered Cardiovascular Constructs under Endoscopic Visualization.

    Science.gov (United States)

    König, Fabian; Hollweck, Trixi; Pfeifer, Stefan; Reichart, Bruno; Wintermantel, Erich; Hagl, Christian; Akra, Bassil

    2012-07-19

    Heart valve disease (HVD) is a globally increasing problem and accounts for thousands of deaths yearly. Currently end-stage HVD can only be treated by total valve replacement, however with major drawbacks. To overcome the limitations of conventional substitutes, a new clinical approach based on cell colonization of artificially manufactured heart valves has been developed. Even though this attempt seems promising, a confluent and stable cell layer has not yet been achieved due to the high stresses present in this area of the human heart. This study describes a bioreactor with a new approach to cell conditioning of tissue engineered heart valves. The bioreactor provides a low pulsatile flow that grants the correct opening and closing of the valve without high shear stresses. The flow rate can be regulated allowing a steady and sensitive conditioning process. Furthermore, the correct functioning of the valve can be monitored by endoscope surveillance in real-time. The tubeless and modular design allows an accurate, simple and faultless assembly of the reactor in a laminar flow chamber. It can be concluded that the bioreactor provides a strong tool for dynamic pre-conditioning and monitoring of colonized heart valve prostheses physiologically exposed to shear stress.

  1. A thrombus susceptibility comparison of two pulsatile Penn State 50 cc left ventricular assist device designs.

    Science.gov (United States)

    Navitsky, Michael A; Deutsch, Steven; Manning, Keefe B

    2013-01-01

    Left ventricular assist devices (LVADs) have proven successful as bridge to transplant devices for patients awaiting donor organs. While survival rates continue to increase, destination therapy remains hindered by thrombus formation within the device. Research has shown that thrombosis is correlated to the fluid dynamics within the device and may be a result of sustained shear rates below 500 s(-1) on the polyurethane blood sac used in the Penn State pulsatile LVAD. Particle image velocimetry is used to compare flow within two 50 cc LVAD designs to assess fluid patterns and quantify wall shear rates in regions known from in vivo studies to be susceptible to thrombus formation. The two designs differ in their front face geometry. The V-1 model has an outward-facing "dome" whereas the face of the V-2 model is flat. A thrombus susceptibility metric, which uses measured wall shear rates and exposure times, was applied to objectively compare pump designs over the entire cardiac cycle. For each design, there are regions where wall shear rates remained below 500 s(-1) for the entire cardiac cycle resulting in high thrombus susceptibility potential. Results of this study indicate that the V-2 device had an overall lower propensity for thrombus formation in the current region of interest. PMID:22825798

  2. Measurement of pulsatile turbulent flow downstream of polyurethane heart valve prosthesis using particle image velocimetry

    Energy Technology Data Exchange (ETDEWEB)

    Kim, J.K.; Sung, J.Y. [Graduate School, Seoul National University, Seoul (Korea); Chang, J.K.; Min, B.G.; Yoo, J.Y. [Seoul National University, Seoul (Korea)

    1998-11-01

    In-vitro flow characteristics downstream of a polyurethane artificial heart valve under a pulsatile flow condition were investigated using Particle Image Velocimetry (PIV). With a triggering system and a time-delay circuit the velocity field downstream of the valve was evaluated in conjunction with the opening behavior of a flexible valve leaflet during a cardiac cycle.. Reynolds shear stress distribution was calculated from the velocity fields at a peak systolic phase. Direct measurements of the wall shear stress by hot-film anemometry (HFA) were compared with the PIV data. The possibilities of vascular complications, such as the thrombus formation and red blood cell damage, could be estimated from the overall view of the instantaneous velocity and stress fields obtained. A correlation between the flow pattern downstream of the valve and the corresponding opening posture of the polyurethane valve membrane gives useful data necessary for the improved design of the frame structure and leaflet geometry of the valve. (author). 11 refs., 8 figs., 5 tabs.

  3. 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.

  4. Pulsatile ocular blood flow among normal subjects and patients with high tension glaucoma

    Directory of Open Access Journals (Sweden)

    Agarwal Harish

    2003-01-01

    Full Text Available Purpose: To estimate pulsatile ocular blood flow (POBF among normal subjects and to compare various parameters in eyes of primary open angle glaucoma with high intraocular pressure (IOP. Methods: POBF was estimated in 95 eyes of 95 normal subjects above the age of 40 years and in 35 eyes of 35 primary open angle glaucoma patients using the OBF system (OBF Labs Ltd., UK. Correlation of age, gender, IOP, pulse amplitude, pulse volume and pulse rate with POBF was studied. POBF values were measured in glaucomatous patients before IOP control and one month later after control of IOP to Results: The mean POBF among normal subjects was 1382.2 + 413ml/min (range 636-2291m/min. Females had a significantly higher mean POBF (1512 + 347ml/min than males (1193 + 312ml/min. The mean IOP among normal subjects was 12.6mmHg and in glaucoma patients, 29.1mmHg. Mean POBF in glaucomatous eyes with initially elevated IOP was 718.9 + 322.6 ml/min, which improved after IOP control to 1129 + 291ml/min. IOP had a strong (P Conclusions: POBF among eyes of normal subjects in this study is higher than reported among Caucasian eyes. Primary open angle glaucoma eyes with high IOP have significantly reduced ocular blood flow. Therapy aimed at lowering IOP has a positive effect on ocular haemodynamics.

  5. 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.

  6. Phantom-based ground-truth generation for cerebral vessel segmentation and pulsatile deformation analysis

    Science.gov (United States)

    Schetelig, Daniel; Säring, Dennis; Illies, Till; Sedlacik, Jan; Kording, Fabian; Werner, René

    2016-03-01

    Hemodynamic and mechanical factors of the vascular system are assumed to play a major role in understanding, e.g., initiation, growth and rupture of cerebral aneurysms. Among those factors, cardiac cycle-related pulsatile motion and deformation of cerebral vessels currently attract much interest. However, imaging of those effects requires high spatial and temporal resolution and remains challenging { and similarly does the analysis of the acquired images: Flow velocity changes and contrast media inflow cause vessel intensity variations in related temporally resolved computed tomography and magnetic resonance angiography data over the cardiac cycle and impede application of intensity threshold-based segmentation and subsequent motion analysis. In this work, a flow phantom for generation of ground-truth images for evaluation of appropriate segmentation and motion analysis algorithms is developed. The acquired ground-truth data is used to illustrate the interplay between intensity fluctuations and (erroneous) motion quantification by standard threshold-based segmentation, and an adaptive threshold-based segmentation approach is proposed that alleviates respective issues. The results of the phantom study are further demonstrated to be transferable to patient data.

  7. A Pulsatile Bioreactor for Conditioning of Tissue-Engineered Cardiovascular Constructs under Endoscopic Visualization

    Directory of Open Access Journals (Sweden)

    Bassil Akra

    2012-07-01

    Full Text Available Heart valve disease (HVD is a globally increasing problem and accounts for thousands of deaths yearly. Currently end-stage HVD can only be treated by total valve replacement, however with major drawbacks. To overcome the limitations of conventional substitutes, a new clinical approach based on cell colonization of artificially manufactured heart valves has been developed. Even though this attempt seems promising, a confluent and stable cell layer has not yet been achieved due to the high stresses present in this area of the human heart. This study describes a bioreactor with a new approach to cell conditioning of tissue engineered heart valves. The bioreactor provides a low pulsatile flow that grants the correct opening and closing of the valve without high shear stresses. The flow rate can be regulated allowing a steady and sensitive conditioning process. Furthermore, the correct functioning of the valve can be monitored by endoscope surveillance in real-time. The tubeless and modular design allows an accurate, simple and faultless assembly of the reactor in a laminar flow chamber. It can be concluded that the bioreactor provides a strong tool for dynamic pre-conditioning and monitoring of colonized heart valve prostheses physiologically exposed to shear stress.

  8. Numerical Study of Turbulent Pulsatile Blood Flow through Stenosed Artery Using Fluid-Solid Interaction

    Directory of Open Access Journals (Sweden)

    Mehdi Jahangiri

    2015-01-01

    Full Text Available The turbulent pulsatile blood flow through stenosed arteries considering the elastic property of the wall is investigated numerically. During the numerical model validation both standard k-ε model and RNG K-ε model are used. Compared with the RNG K-ε model, the standard K-ε model shows better agreement with previous experimental results and is better able to show the reverse flow region. Also, compared with experimental data, the results show that, up to 70% stenosis, the flow is laminar and for 80% stenosis the flow becomes turbulent. Assuming laminar or turbulent flow and also rigid or elastic walls, the results are compared with each other. The investigation of time-averaged shear stress and the oscillatory shear index for 80% stenosis show that assuming laminar flow will cause more error than assuming a rigid wall. The results also show that, in turbulent flow compared with laminar flow, the importance of assuming a flexible artery wall is more than assuming a rigid artery wall.

  9. Numerical analysis of bypass model geometrical parameters influence on pulsatile blood flow

    Directory of Open Access Journals (Sweden)

    Jonášová A.

    2011-06-01

    Full Text Available The present study is focused on the analysis of pulsatile blood flow in complete idealized 3D bypass models in dependence on three main geometrical parameters (stenosis degree, junction angle and diameter ratio. Assuming the blood to be an incompressible Newtonian fluid, the non-linear system of Navier-Stokes equations is integrated in time by a fully implicit second-order accurate fractional-step method. The space discretization is performed with the help of the cell-centred finite volume method formulated for unstructured tetrahedral grids. In order to model a realistic coronary blood flow, a time-dependent flow rate taken from corresponding literature is considered. For the analysis of obtained numerical results, special emphasis is placed on their comparison in the form of velocity isolines at several selected cross-sections during systolic and diastolic phases. The remainder of this paper is devoted to discussion of walls shear stress distribution and its oscillatory character described by the oscillatory shear index with regard to areas prone to development of intimal hyperplasia or to thrombus formation.

  10. 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 press-coated tablets of 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). PMID:25721985

  11. Superficial temporal artery pseudoaneurysm presenting as a growing, pulsatile, and tender mass

    Science.gov (United States)

    Seferi, Arsen; Alimehmeti, Ridvan; Pajaj, Ermira; Vyshka, Gentian

    2016-01-01

    Background: Superficial temporal artery (STA) pseudoaneurysms have been reported in the literature since the mid of seventeenth century from Bartholin, however, there is an increasing number of cases, suggesting a diversity of etiological factors. Among these, traumatic events, even of an iatrogenic nature, have been identified as causative factors for nonspontaneous STA pseudoaneurysms. Regional pain and tenderness, troublesome pulsations of the mass, cosmetic concerns as well as the risk of bleeding warrant a thorough evaluation and a definite interventional approach to the condition. Case Description: A 21-year-old Caucasian male searched medical advice for a growing, tender, and pulsatile mass on his right temple, with isolated and short episodes of lancinating sensations, after sustaining a blunt trauma following a hit with a stick half a year before the admission. Enhanced cranial computed tomography and angiography confirmed the diagnosis of an STA pseudoaneurysm. A direct percutaneous aspiration, as well as ultrasonography, was performed prior to the neurosurgical intervention, with the complete removal of the mass. Conclusions: STA pseudoaneurysms require a careful evaluation and a conclusive approach in order to avoid the risk of a growing mass and other nonremote complications such as bone erosions and bleeding. Different treatment options are available, including endovascular obliteration and embolization, however, surgical removal after ligation of the afferent and efferent segments of the vessel seem to be highly effective.

  12. How to use and interpret hormone ratios.

    Science.gov (United States)

    Sollberger, Silja; Ehlert, Ulrike

    2016-01-01

    Hormone ratios have become increasingly popular throughout the neuroendocrine literature since they offer a straightforward way to simultaneously analyze the effects of two interdependent hormones. However, the analysis of ratios is associated with statistical and interpretational concerns which have not been sufficiently considered in the context of endocrine research. The aim of this article, therefore, is to demonstrate and discuss these issues, and to suggest suitable ways to address them. In a first step, we use exemplary testosterone and cortisol data to illustrate that one major concern of ratios lies in their distribution and inherent asymmetry. As a consequence, results of parametric statistical analyses are affected by the ultimately arbitrary decision of which way around the ratio is computed (i.e., A/B or B/A). We suggest the use of non-parametric methods as well as the log-transformation of hormone ratios as appropriate methods to deal with these statistical problems. However, in a second step, we also discuss the complicated interpretation of ratios, and propose moderation analysis as an alternative and oftentimes more insightful approach to ratio analysis. In conclusion, we suggest that researchers carefully consider which statistical approach is best suited to investigate reciprocal hormone effects. With regard to the hormone ratio method, further research is needed to specify what exactly this index reflects on the biological level and in which cases it is a meaningful variable to analyze.

  13. LH (Luteinizing Hormone) Test

    Science.gov (United States)

    ... reason for the delayed puberty. Some of the causes for delayed puberty can include: Failure of the ovaries or testicles Hormone deficiency Turner syndrome Klinefelter syndrome Chronic infections Cancer Eating disorder (anorexia nervosa) ^ Back to top Is there anything ...

  14. Growth hormone deficiency - children

    Science.gov (United States)

    ... be done include: Insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein ... themselves the shot. Treatment with growth hormone is long-term, often lasting for several years. During this ...

  15. Hormones and female sexuality

    OpenAIRE

    Bjelica Artur L.; Kapamadžija Aleksandra; Maticki-Sekulić Milana

    2003-01-01

    Introduction In contrast to animal species in which linear relationships exist between hormonal status and sexual behaviour sexuality in human population is not determined so simply by the level of sexual steroids. The article analyses female sexuality in the light of hormonal status. Administration of sexual steroids during pregnancy and sexual differentiation High doses of gestagens, especially those with high androgen activity, widely used against miscarriages may lead to tomboys, but with...

  16. Bioidentical Hormone Therapy

    OpenAIRE

    Files, Julia A.; Ko, Marcia G.; Pruthi, Sandhya

    2011-01-01

    The change in hormonal milieu associated with perimenopause and menopause can lead to a variety of symptoms that can affect a woman's quality of life. Postmenopausal hormone therapy (HT) is an effective, well-tolerated treatment for these symptoms. However, combined HT consisting of conjugated equine estrogen and medroxyprogesterone acetate has been associated with an increased number of health risks when compared with conjugated equine estrogen alone or placebo. As a result, some women are t...

  17. Gastrointestinal hormones regulating appetite

    OpenAIRE

    Chaudhri, Owais; Small, Caroline; Bloom, Steve

    2006-01-01

    The role of gastrointestinal hormones in the regulation of appetite is reviewed. The gastrointestinal tract is the largest endocrine organ in the body. Gut hormones function to optimize the process of digestion and absorption of nutrients by the gut. In this capacity, their local effects on gastrointestinal motility and secretion have been well characterized. By altering the rate at which nutrients are delivered to compartments of the alimentary canal, the control of food intake arguably cons...

  18. Body segments and growth hormone.

    OpenAIRE

    Bundak, R; Hindmarsh, P. C.; Brook, C G

    1988-01-01

    The effects of human growth hormone treatment for five years on sitting height and subischial leg length of 35 prepubertal children with isolated growth hormone deficiency were investigated. Body segments reacted equally to treatment with human growth hormone; this is important when comparing the effect of growth hormone on the growth of children with skeletal dysplasias or after spinal irradiation.

  19. Treatment with thyroid hormone.

    Science.gov (United States)

    Biondi, Bernadette; Wartofsky, Leonard

    2014-06-01

    Thyroid hormone deficiency can have important repercussions. Treatment with thyroid hormone in replacement doses is essential in patients with hypothyroidism. In this review, we critically discuss the thyroid hormone formulations that are available and approaches to correct replacement therapy with thyroid hormone in primary and central hypothyroidism in different periods of life such as pregnancy, birth, infancy, childhood, and adolescence as well as in adult patients, the elderly, and in patients with comorbidities. Despite the frequent and long term use of l-T4, several studies have documented frequent under- and overtreatment during replacement therapy in hypothyroid patients. We assess the factors determining l-T4 requirements (sex, age, gender, menstrual status, body weight, and lean body mass), the major causes of failure to achieve optimal serum TSH levels in undertreated patients (poor patient compliance, timing of l-T4 administration, interferences with absorption, gastrointestinal diseases, and drugs), and the adverse consequences of unintentional TSH suppression in overtreated patients. Opinions differ regarding the treatment of mild thyroid hormone deficiency, and we examine the recent evidence favoring treatment of this condition. New data suggesting that combined therapy with T3 and T4 could be indicated in some patients with hypothyroidism are assessed, and the indications for TSH suppression with l-T4 in patients with euthyroid multinodular goiter and in those with differentiated thyroid cancer are reviewed. Lastly, we address the potential use of thyroid hormones or their analogs in obese patients and in severe cardiac diseases, dyslipidemia, and nonthyroidal illnesses.

  20. Hormonal control of inflammatory responses

    OpenAIRE

    Garcia-Leme, J.; Farsky, Sandra P

    1993-01-01

    Almost any stage of inflammatory and immunological responses is affected by hormone actions. This provides the basis for the suggestion that hormones act as modulators of the host reaction against trauma and infection. Specific hormone receptors are detected in the reactive structures in inflamed areas and binding of hormone molecules to such receptors results in the generation of signals that influence cell functions relevant for the development of inflammatory responses. Diversity of hormon...

  1. The clinical research on the variation of fetal pulmonary artery pulsatility index in late pregnancy%中晚孕胎肺动脉搏动指数变化规律的实验研究

    Institute of Scientific and Technical Information of China (English)

    方凌峰; 姜凡; 彭梅; 罗平; 顾莉莉; 张志华

    2013-01-01

    Objective To observe the changes of normal fetal distal branch pulsatility index of pulmonary artery (PIPA )in pregnancy, in order to explore the clinical value of PIPA in fetal lung maturity prediction. Methods 217 cases of normal fetuses had been collected, by using color Doppler technology;the left and right pulmonary artery distal PIPA of each case were detected to analyze its relationship with the gestational age. Results The left and right pulmonary artery PIPA of normal fetuses before 37 weeks of gestation had a gradually rising trend,and gestation-al age and the left and right pulmonary artery PIPA was correlated (left pulmonary artery r=0.521, P  化有一定规律性,可能成为无创性评估胎肺成熟度的指标。

  2. 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

  3. 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.

  4. Pulsatility Index in Aortic Coarctation: A Possible Way to Evaluate Factors Affecting Stenting Outcome

    Directory of Open Access Journals (Sweden)

    Mohammad Reza Keramati

    2012-03-01

    Full Text Available Background: The pulsatility index (PI shows continuous blood flow to the end organs and is a significant factor believed to decrease in aortic coarctation. Correction of this factor is of great importance in the treatment of stenotic lesions of the aorta. However, there are minimal data regarding the trend of changes in the PI after stent implantation. Furthermore, the association between the PI and other echocardiographic indices in patients undergoing stent implantation is unclear. This study was designed to evaluate changes in the PI following stenting and its correlation with other echocardiographic indices. Methods: Twenty-three patients with a diagnosis of aortic coarctation consecutively underwent two-dimensional and Doppler echocardiographic imaging modalities twice (before and after stenting. The patients were divided into two groups based on the percentage of increase in the PI after stenting ( < 50% or ≥ 50%. The relation between the post-stenting PI and the baseline echocardiographic indices was assessed. Results: The PI was increased from 0.89 (SD = 0.30 to 1.75 (SD = 0.51 after stenting (p value < 0.001. Baseline diastolic/systolic velocity (D/S velocity ratio of the abdominal aorta (p value = 0.013, mean velocity (p value = 0.033, and peak gradient of the descending aorta (p value = 0.033 were significantly higher in the patients with ≥ 50% increase in the PI after stenting. Conclusion: Our findings showed that elevation in the PI after stenting was a predictable criterion in patients with aortic coarctation: it was predicted by some baseline clinical and echocardiographic indices. Baseline D/S ratio velocity of the abdominal aorta, mean velocity and peak gradient of the descending aorta, and baseline systolic blood pressure were the statistically significant indices to predict ≥ 50% increase in the PI in our patients.

  5. 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

    2016-01-01

    Objective 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. Methods 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. Results 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. Conclusions 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. PMID:27311899

  6. Development of press-coated, floating-pulsatile drug delivery of lisinopril.

    Science.gov (United States)

    Jagdale, Swati C; Suryawanshi, Vishnu M; Pandya, Sudhir V; Kuchekar, Bhanudas S; Chabukswar, Aniruddha R

    2014-06-01

    Lisinopril is an angiotensin-converting enzyme (ACE) inhibitor, primarily used for the treatment of hypertension, congestive heart failure, and heart attack. It belongs to BCS class III having a half-life of 12 hrs and 25% bioavailability. The purpose of the present work was to develop a press-coated, floating-pulsatile drug delivery system. The core tablet was formulated using the super-disintegrants crosprovidone and croscarmellose sodium. A press-coated tablet (barrier layer) contained the polymer carrageenan, xanthan gum, HPMC K4M, and HPMC K15M. The buoyant layer was optimized with HPMC K100M, sodium bicarbonate, and citric acid. The tablets were evaluated for physical characteristics, floating lag time, swelling index, FTIR, DSC, and in vitro and in vivo behavior. The 5% superdisintgrant showed good results. The FTIR and DSC study predicted no chemical interactions between the drug and excipients. The formulation containing xanthan gum showed drug retaining abilities, but failed to float. The tablet containing HPMC K15M showed a high swelling index. The lag time for the tablet coated with 200 mg carrageenan was 3±0.1 hrs with 99.99±1.5% drug release; with 140 mg HPMC K4M, the lag time was 3±0.1 hrs with 99.71±1.2% drug release; and with 120 mg HPMC K15M, the lag time was 3±0.2 hrs with 99.98±1.7% drug release. The release mechanism of the tablet followed the Korsmeyer-Peppas equation and a first-order release pattern. Floating and lag time behavior have shown good in vitro and in vivo correlations. PMID:24959410

  7. Amoxicillin pulsatile - MiddleBrook: APC 111, APC-111, PULSYS-enhanced amoxicillin.

    Science.gov (United States)

    2007-01-01

    MiddleBrook Pharmaceuticals (formerly Advancis Pharmaceutical) is developing an improved version of amoxicillin using its pulsatile oral drug delivery technology, called PULSYS. Amoxicillin PULSYS is intended to provide a lower treatment dose, once-daily alternative to currently approved amoxicillin and penicillin regimens for the treatment of adolescents/adults with pharyngitis and/or tonsillitis. If amoxicillin PULSYS is approved, it will be the first and only once-daily amoxicillin therapy approved for use in the US. Regulatory submissions for the treatment of pharyngitis/tonsillitis have been made in the US. Amoxicillin PULSYS is in clinical development for the treatment of pharyngitis and/or tonsillitis due to group A streptococcal infections in adolescents/adults as a tablet formulation. MiddleBrook was conducting clinical development of a sprinkle formulation for children. However, this has been put on hold for financial reasons. MiddleBrook is seeking regulatory approval for this product as a 505(b)(2) product, which is one that is not considered to be a completely new product, but is also not a generic product. It is a product with some differences from a previously approved product and clinical data to support such differences are required; however, the basic safety and efficacy studies may have been conducted by other organisations. In June 2007, Advancis Pharmaceutical was renamed as MiddleBrook Pharmaceuticals, Inc. MiddleBrook and Par Pharmaceuticals entered a co-promotion agreement for this product in June 2004. Par was to fund future development in exchange for co-exclusive marketing rights and exclusive rights to sell amoxicillin PULSYS. MiddleBrook retained responsibility for the manufacturing programme and also retained all patents and brand names and was responsible for their enforcement. However, this collaboration was subsequently terminated in August 2005 by Par Pharmaceutical. MiddleBrook received the US $4.75 million R&D reimbursement

  8. Headache And Hormones

    Directory of Open Access Journals (Sweden)

    Shukla Rakesh

    2002-01-01

    Full Text Available There are many reasons to suggest a link between headache and hormones. Migraine is three times common in women as compared to men after puberty, cyclic as well as non-cyclic fluctuations in sex hormone levels during the entire reproductive life span of a women are associated with changes in frequency or severity of migraine attack, abnormalities in the hypothalamus and pineal gland have been observed in cluster headache, oestrogens are useful in the treatment of menstrual migraine and the use of melatonin has been reported in various types of primary headaches. Headache associated with various endocrinological disorders may help us in a better understanding of the nociceptive mechanisms involved in headache disorders. Prospective studies using headache diaries to record the attacks of headache and menstrual cycle have clarified some of the myths associated with menstrual migraine. Although no change in the absolute levels of sex hormones have been reported, oestrogen withdrawal is the most likely trigger of the attacks. Prostaglandins, melatonin, opioid and serotonergic mechanisms may also have a role in the pathogenesis of menstrual migraine. Guidelines have been published by the IHS recently regarding the use of oral contraceptives by women with migraine and the risk of ischaemic strokes in migraineurs on hormone replacement therapy. The present review includes menstrual migraine, pregnancy and migraine, oral contraceptives and migraine, menopause and migraine as well as the hormonal changes in chronic migraine.

  9. Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model

    OpenAIRE

    Symersky, P.; Budde, R. P. J.; Westers, P.; Mol, de, B.A.J.M.; Prokop, M

    2011-01-01

    Objectives Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. Methods A Medtronic Hall tilting disc (MH), and Carbomedics (CM), St Jude (SJM), and ON-X bileaflet valves underwent CT in an in-vitro model using retrospective gating with a 64 detector CT system in stati...

  10. 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....

  11. 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....

  12. 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....

  13. 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....

  14. Evolution of vortical structures in a curved artery model with non-Newtonian blood-analog fluid under pulsatile inflow conditions

    Science.gov (United States)

    Najjari, Mohammad Reza; Plesniak, Michael W.

    2016-06-01

    Steady flow and physiological pulsatile flow in a rigid 180° curved tube are investigated using particle image velocimetry. A non-Newtonian blood-analog fluid is used, and in-plane primary and secondary velocity fields are measured. A vortex detection scheme ( d 2-method) is applied to distinguish vortical structures. In the pulsatile flow case, four different vortex types are observed in secondary flow: deformed-Dean, Dean, Wall and Lyne vortices. Investigation of secondary flow in multiple cross sections suggests the existence of vortex tubes. These structures split and merge over time during the deceleration phase and in space as flow progresses along the 180° curved tube. The primary velocity data for steady flow conditions reveal additional vortices rotating in a direction opposite to Dean vortices—similar to structures observed in pulsatile flow—if the Dean number is sufficiently high.

  15. High Frequency Pulsatile Electromagnetic Fields and Ultrasound Pulsatile Fields Impact on Germination Dynamic at Ocimum basilicum L. and O. basilicum var. purpurascens Benth., Observed with Open Source Software’s

    Directory of Open Access Journals (Sweden)

    Ioan ONAC

    2016-06-01

    Full Text Available Basil (Ocimum sp., generally knowned as “king of herbs” due to its pharmaceutical and culinary properties, is considered to be a native plant derived from Africa and Asia. Ocimum sp. grows in tropical and sub-tropical regions with more than 50 species knowned till present time. Germination percent of Ocimum sp. is considered to be between 85-95%. Even though Ocimum sp. are considered to have fast germination velocity index (GVI, short mean germination time (MGT and increased seedling vigor index (SVI values, their experimental monitoring is done with specialized software’s that are expensive. Low cost scientific solutions are keen on open source software germination protocols. For observing the accuracy of open source C.A.D. software’s Ocimum sp. seeds where submitted to high frequency pulsatile electromagnetic fields (300 impulses/3 peak penetrance - 293 W and ultrasound pulsatile fields (1/2 pulses by 0.5 W/cm2. All sequence images where taken using a positive/negative photo filter enhancing differences in seed development. At the end of the experiment all images where transformed into vector formats (dwg. On the dwg extension, selective free plug-ins such as Face Centroid and Area Properties help to collect data like seed development on X/Y scale, area, perimeter, no. of germinated seeds, length of seedling root, hypocotyl length.

  16. Stress and hormones

    Directory of Open Access Journals (Sweden)

    Salam Ranabir

    2011-01-01

    Full Text Available In the modern environment one is exposed to various stressful conditions. Stress can lead to changes in the serum level of many hormones including glucocorticoids, catecholamines, growth hormone and prolactin. Some of these changes are necessary for the fight or flight response to protect oneself. Some of these stressful responses can lead to endocrine disorders like Graves′ disease, gonadal dysfunction, psychosexual dwarfism and obesity. Stress can also alter the clinical status of many preexisting endocrine disorders such as precipitation of adrenal crisis and thyroid storm.

  17. Transdermal iontophoresis of gonadotropin releasing hormone (LHRH) and two analogues.

    Science.gov (United States)

    Miller, L L; Kolaskie, C J; Smith, G A; Rivier, J

    1990-06-01

    Gonadotropin releasing hormone (GnRH), as well as an antagonist [Ac-D2Nal,1 D4ClPhe,2 D3Pal,3 NicLys,5 DNicLys,6 ILys,8 DAla10] GnRH.HOAc (1) and a superagonist [DTrp6, Pro9-NHEt]GnRH (2), have been electrochemically driven across excised hairless mouse skin. Determined by HPLC analysis, the delivery rate from aqueous solution into isotonic saline at 0.5 mA cm-2 was as high as 19 nM cm-2 h-1 for 2. Because of its insolubility in water, analogue 1 could only be delivered from an acidic donor solution. Analogue 2 was also delivered in pulsatile fashion using current on/off cycles. For all three peptides, passive transport was negligible and stability is evident when in contact with the stratum corneum. Slow metabolism occurs when GnRH contacts the dermal side of hairless mouse skin. PMID:2203894

  18. Numerical simulation of pulsatile flow with newtonian and non-newtonian behavior in arterial stenosis

    Directory of Open Access Journals (Sweden)

    MM Movahedi

    2008-03-01

    Full Text Available Background: There is considerable evidence that vascular fluid dynamics plays an important role in the developmentand prevalence of atherosclerosis which is one of the most widespread disease in humans .The onset and prevalence of atherosclerosis hemodynamic parameter are largely affected by geometric parameters. If any obstacle interferes with the blood flow, the above parameters change dramatically. Most of the arterial diseases, such as atherosclerosis, occur in the arteries with complex patterns of fluid flow where the blood dynamics plays an important role. Arterial stenosis mostly occurs in an area with a complex pattern of fluid flow, such as coronary artery, aorta bifurcation, carotid and vessels of lower limbs. During the past three decades, many experimental studies have been performed on the hemodynamic role of the blood in forming sediment in the inner wall of the vessels. It has been shown that forming sediment in the inner wall of vessels depends on the velocity of fluid and also on the amount of wall shear stress.Methods: We have examined the effect on the blood flow of local stenosis in carotid artery in numerical form using the incompressible Navier-Stockes equations. The profile of the velocity in different parts and times in the pulsatile cycle, separation and reattachment points on the wall, the distance stability of flow and also alteration caused by the wall shear stress in entire vessel were shown and compared with two behaviors flow (Newtonian and Non-Newtonian.Finally we describe the influence of the severity of the stenosis on the separation and reattachmentpoints for a Non-Newtonian fuid. Results: In the present study, we have pointed very low and high oscillating WSS (Wall Shear Stress values play a significant role in the development of forming sediment in the inner wall of vessels. Also, we obtain this probability is higher for Newtonian than Non-Newtonian fluid behavior.Conclusion: Based on our results, the

  19. 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.

  20. Pulsatile flow in the aorta of the LVAD supported heart studied using particle image velocimetry

    Science.gov (United States)

    Moyedi, Zahra

    Currently many patients die because of the end-stage heart failure, mainly due to the reduced number of donor heart transplant organs. Studies show that a permanent left ventricular assist device (LVAD), a battery driven pump which is surgically implanted, increased the survival rate of patients with end-stage heart failure and improved considerably their quality of life. The inlet conduit of the LVAD is attached to the left ventricle and the outflow conduit anastomosed to the ascending aorta. The purpose of LVAD support is to help a weakened heart to pump blood to the rest of the body. However LVAD can cause some alterations of the natural blood flow. When your blood comes in contact with something that isn't a natural part of your body blood clots can occur and disrupt blood flow. Aortic valve integrity is vital for optimal support of left ventricular assist LVAD. Due to the existence of high continuous transvalvular pressure on the aortic valve, the opening frequency of the valve is reduced. To prevent the development of aortic insufficiency, aortic valve closure during LVAD implantation has been performed. However, the closed aortic valve reduces wash out of the aortic root, which causes blood stagnation and potential thrombus formation. So for this reason, there is a need to minimize the risks of occurring blood clot, by having more knowledge about the flow structure in the aorta during LVAD use. The current study focuses on measuring the flow field in the aorta of the LVAD assisted heart with two different types of aortic valve (Flat and Finned) using the SDSU cardiac simulator. The pulsatile pump that mimics the natural pulsing action of the heart also added to the system. The flow field is visualized using Particle Image Velocimetry (PIV). Furthermore, The fluid mechanics of aorta has been studied when LVAD conduit attached to two different locations (proximal and distal to the aortic valve) with pump speeds of 8,000 to 10,000 revolutions per minute (RPM

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

    International Nuclear Information System (INIS)

    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 ∗ 10−9 m2/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

  2. Simultaneous assessment of red blood cell aggregation and oxygen saturation under pulsatile flow using high-frequency photoacoustics

    Science.gov (United States)

    Bok, Tae-Hoon; Hysi, Eno; Kolios, Michael C.

    2016-01-01

    We investigate the feasibility of photoacoustic (PA) imaging for assessing the correlation between red blood cell (RBC) aggregation and the oxygen saturation (sO2) in a simulated pulsatile blood flow system. For the 750 and 850 nm illuminations, the PA amplitude (PAA) increased and decreased as the mean blood flow velocity decreased and increased, respectively, at all beat rates (60, 120 and 180 bpm). The sO2 also cyclically varied, in phase with the PAA for all beat rates. However, the linear correlation between the sO2 and the PAA at 850 nm was stronger than that at 750 nm. These results suggest that the sO2 can be correlated with RBC aggregation induced by decreased mean shear rate in pulsatile flow, and that the correlation is dependent on the optical wavelength. The hemodynamic properties of blood flow assessed by PA imaging may be used to provide a new biomarker for simultaneous monitoring blood viscosity related to RBC aggregation, oxygen delivery related to the sO2 and their clinical correlation.

  3. Multidetector CT imaging of mechanical prosthetic heart valves: quantification of artifacts with a pulsatile in-vitro model

    Energy Technology Data Exchange (ETDEWEB)

    Symersky, Petr [Onze Lieve Vrouwe Gasthuis, Department of Cardiothoracic Surgery, Oosterpark 9, P.O box 95500, Amsterdam (Netherlands); Academic Medical Center, Department of Cardiothoracic Surgery, Amsterdam (Netherlands); Budde, Ricardo P.J. [University Medical Center, Department of Radiology, Utrecht (Netherlands); Westers, Paul [Julius Center for Health Sciences and Primary Care, Department of Biostatistics, Utrecht (Netherlands); Mol, Bas A.J.M. de [Academic Medical Center, Department of Cardiothoracic Surgery, Amsterdam (Netherlands); University of Technology Eindhoven, Department of Biomedical Engineering, Eindhoven (Netherlands); Prokop, Mathias [Radboud University Nijmegen Medical Center, Department of Radiology, Nijmegen (Netherlands)

    2011-10-15

    Multidetector computed tomography (MDCT) can detect the cause of prosthetic heart valve (PHV) dysfunction but is hampered by valve-induced artifacts. We quantified artifacts of four PHV using a pulsatile in-vitro model and assessed the relation to leaflet motion and valve design. A Medtronic Hall tilting disc (MH), and Carbomedics (CM), St Jude (SJM), and ON-X bileaflet valves underwent CT in an in-vitro model using retrospective gating with a 64 detector CT system in stationary and pulsatile conditions. Artifacts and radiopaque component volumes were quantified with thresholds based on surrounding structures and valvular components. Hypodense artifacts volumes (mm{sup 3}) were 1,029 {+-} 147, 535 {+-} 53, 371 {+-} 16, and 366 {+-} 18 for the SJM, MH, CM and ON-X valves (p < 0.001 except for the latter two valves p = 0.43). Hyperdense artifact volumes were 3,546 {+-} 141, 2,387 {+-} 103, 2,003 {+-} 102, and 3,033 {+-} 31 for the SJM, MH, CM and ON-X valve, respectively (all differences p < 0.001). Leaflet motion affected hypodense (F = 41.5, p < 0.001) and hyperdense artifacts (F = 53.7, p < 0.001). Closed and moving leaflets were associated with the least and the most artifacts respectively (p < 0.001, both artifact types). Both valve design and leaflet motion affect PHV-induced artifacts. Best imaging results may be expected for the CM valve during phases in which the leaflets are closed. (orig.)

  4. Simultaneous assessment of red blood cell aggregation and oxygen saturation under pulsatile flow using high-frequency photoacoustics.

    Science.gov (United States)

    Bok, Tae-Hoon; Hysi, Eno; Kolios, Michael C

    2016-07-01

    We investigate the feasibility of photoacoustic (PA) imaging for assessing the correlation between red blood cell (RBC) aggregation and the oxygen saturation (sO2) in a simulated pulsatile blood flow system. For the 750 and 850 nm illuminations, the PA amplitude (PAA) increased and decreased as the mean blood flow velocity decreased and increased, respectively, at all beat rates (60, 120 and 180 bpm). The sO2 also cyclically varied, in phase with the PAA for all beat rates. However, the linear correlation between the sO2 and the PAA at 850 nm was stronger than that at 750 nm. These results suggest that the sO2 can be correlated with RBC aggregation induced by decreased mean shear rate in pulsatile flow, and that the correlation is dependent on the optical wavelength. The hemodynamic properties of blood flow assessed by PA imaging may be used to provide a new biomarker for simultaneous monitoring blood viscosity related to RBC aggregation, oxygen delivery related to the sO2 and their clinical correlation. PMID:27446705

  5. Methicillin Resistant Staphylococcus Aureus Biofilm Formation Over A Separated Flow Region Under Steady And Pulsatile Flow Conditions

    Science.gov (United States)

    Salek, M. Mehdi; Martinuzzi, Robert

    2012-02-01

    Several researchers have observed that the formation, morphology and susceptibility of bacterial biofilms are affected by the local hydrodynamic condition and, in particular, shear stresses acting on the fluid-biofilm interface. A backwards facing step (BFS) experimental model has been widely utilized as an in vitro model to examine and characterize the effect of flow separation and recirculation zones comparable to those present within various medical devices as well as those observed in vivo. The specific geometry of BFS covers a vide range of flow features observed in physiological or environmental conditions. The hypothesis of this study is that the flow behavior and structures can effectively contribute to the transport and attachment of cells and affecting the morphology of adhered colonies as well as suspended structures (i.e. biofilm streamers). Hence, the formation of the recirculation region occurring within a backward facing step (BFS) under steady and pulsatile conditions as well as three-dimensional flow structures arising close to the side walls are investigated to correlate to biofilms behavior. This hypothesis is investigated using a backward facing step incorporated into a flow cell under steady and pulsatile flow regimes to study the growth of methicillin resistant Staphylococcus aureus (MRSA) UC18 as the study microorganism.

  6. An Ultrasound Simulation Model for the Pulsatile Blood Flow Modulated by the Motion of Stenosed Vessel Wall.

    Science.gov (United States)

    Zhang, Qinghui; Zhang, Yufeng; Zhou, Yi; Zhang, Kun; Zhang, Kexin; Gao, Lian

    2016-01-01

    This paper presents an ultrasound simulation model for pulsatile blood flow, modulated by the motion of a stenosed vessel wall. It aims at generating more realistic ultrasonic signals to provide an environment for evaluating ultrasound signal processing and imaging and a framework for investigating the behaviors of blood flow field modulated by wall motion. This model takes into account fluid-structure interaction, blood pulsatility, stenosis of the vessel, and arterial wall movement caused by surrounding tissue's motion. The axial and radial velocity distributions of blood and the displacement of vessel wall are calculated by solving coupled Navier-Stokes and wall equations. With these obtained values, we made several different phantoms by treating blood and the vessel wall as a group of point scatterers. Then, ultrasound echoed signals from oscillating wall and blood in the axisymmetric stenotic-carotid arteries were computed by ultrasound simulation software, Field II. The results show better consistency with corresponding theoretical values and clinical data and reflect the influence of wall movement on the flow field. It can serve as an effective tool not only for investigating the behavior of blood flow field modulated by wall motion but also for quantitative or qualitative evaluation of new ultrasound imaging technology and estimation method of blood velocity. PMID:27478840

  7. Application of design of experiment for polyox and xanthan gum coated floating pulsatile delivery of sumatriptan succinate in migraine treatment.

    Science.gov (United States)

    Jagdale, Swati C; Pawar, Chandrakala R

    2014-01-01

    Migraine follows circadian rhythm in which headache is more painful at the awakening time. This needs administration of dosage form at night time to release drug after lag period when pain gets worse. Sumatriptan succinate is a drug of choice for migraine. Sumatriptan succinate has bitter taste, low oral bioavailability, and shorter half-life. Present work deals with application of design of experiment for polyox and xanthan gum in development of press coated floating pulsatile tablet. Floating pulsatile concept was applied to increase gastric residence of the dosage form. Burst release was achieved through immediate release tablet using crospovidone as superdisintegrant (10%). Pulse lag time was achieved using swellable polymer polyox WSR 205 and xanthan gum. 3(2) experimental design was applied. Optimized formulation was evaluated for physical characteristics and in-vitro and in-vivo study. From results, it can be concluded that optimized batch F8 containing polyox WSR205 (72.72%) and xanthan gum (27.27%) of total weight of polymer has shown floating lag time of 55 ± 2 sec, drug content of 100.35 ± 0.4%, hardness of 6 ± 0.1 Kg/cm(2), and 98.69 ± 2% drug release in pulse manner with lag time of 7 ± 0.1 h. Optimized batch showed prolong gastric residence which was confirmed by in-vivo X-ray study. PMID:25530963

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

    International Nuclear Information System (INIS)

    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 (R2 = 0.982) and a mean absolute error (e) of 0.323 L min−1, while for head, R2 = 0.933 and e = 7.682 mmHg were obtained. R2 = 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

  9. Hormonal contraception and venous thromboembolism

    DEFF Research Database (Denmark)

    Lidegaard, Øjvind; Milsom, Ian; Geirsson, Reynir Tomas;

    2012-01-01

    New studies about the influence of hormonal contraception on the risk of venous thromboembolism (VTE) have been published.......New studies about the influence of hormonal contraception on the risk of venous thromboembolism (VTE) have been published....

  10. SHBG (Sex Hormone Binding Globulin)

    Science.gov (United States)

    ... as: Testosterone-estrogen Binding Globulin; TeBG Formal name: Sex Hormone Binding Globulin Related tests: Testosterone , Free Testosterone, ... I should know? How is it used? The sex hormone binding globulin (SHBG) test may be used ...

  11. Growth Hormone Deficiency in Children

    Science.gov (United States)

    ... which the body does not make enough growth hormone (GH). GH is made by the pituitary gland, a ... blood test checks levels of IGF-1, a hormone that reflects GH levels. • GH stimulation test. The child is given ...

  12. Thyroid hormone deiodination

    NARCIS (Netherlands)

    T.J. Visser (Ton)

    1980-01-01

    textabstractThe enzymatic deiodination of thyroid hormone is an important process since it concerns- among other things- the regulation of thyromimetic activity at the site of the target organ. To understand the mechanism of this regulation it is necessary to have a detailed knowledge of the mode of

  13. The Intermodulation Lockin Analyzer

    CERN Document Server

    Tholen, Erik A; Forchheimer, Daniel; Schuler, Vivien; Tholen, Mats O; Hutter, Carsten; Haviland, David B

    2011-01-01

    Nonlinear systems can be probed by driving them with two or more pure tones while measuring the intermodulation products of the drive tones in the response. We describe a digital lock-in analyzer which is designed explicitly for this purpose. The analyzer is implemented on a field-programmable gate array, providing speed in analysis, real-time feedback and stability in operation. The use of the analyzer is demonstrated for Intermodulation Atomic Force Microscopy. A generalization of the intermodulation spectral technique to arbitrary drive waveforms is discussed.

  14. Miniature mass analyzer

    CERN Document Server

    Cuna, C; Lupsa, N; Cuna, S; Tuzson, B

    2003-01-01

    The paper presents the concept of different mass analyzers that were specifically designed as small dimension instruments able to detect with great sensitivity and accuracy the main environmental pollutants. The mass spectrometers are very suited instrument for chemical and isotopic analysis, needed in environmental surveillance. Usually, this is done by sampling the soil, air or water followed by laboratory analysis. To avoid drawbacks caused by sample alteration during the sampling process and transport, the 'in situ' analysis is preferred. Theoretically, any type of mass analyzer can be miniaturized, but some are more appropriate than others. Quadrupole mass filter and trap, magnetic sector, time-of-flight and ion cyclotron mass analyzers can be successfully shrunk, for each of them some performances being sacrificed but we must know which parameters are necessary to be kept unchanged. To satisfy the miniaturization criteria of the analyzer, it is necessary to use asymmetrical geometries, with ion beam obl...

  15. Analyzing in the present

    DEFF Research Database (Denmark)

    Revsbæk, Line; Tanggaard, Lene

    2015-01-01

    the interdependency between researcher and researched. On this basis, we advocate an explicit “open-state-of mind” listening as a key aspect of analyzing qualitative material, often described only as a matter of reading transcribed empirical materials, reading theory, and writing. The article contributes......The article presents a notion of “analyzing in the present” as a source of inspiration in analyzing qualitative research materials. The term emerged from extensive listening to interview recordings during everyday commuting to university campus. Paying attention to the way different parts...... of various interviews conveyed diverse significance to the listening researcher at different times became a method of continuously opening up the empirical material in a reflexive, breakdown-oriented process of analysis. We argue that situating analysis in the present of analyzing emphasizes and acknowledges...

  16. Analyzing binding data.

    Science.gov (United States)

    Motulsky, Harvey J; Neubig, Richard R

    2010-07-01

    Measuring the rate and extent of radioligand binding provides information on the number of binding sites, and their affinity and accessibility of these binding sites for various drugs. This unit explains how to design and analyze such experiments.

  17. Software Design Analyzer System

    Science.gov (United States)

    Tausworthe, R. C.

    1985-01-01

    CRISP80 software design analyzer system a set of programs that supports top-down, hierarchic, modular structured design, and programing methodologies. CRISP80 allows for expression of design as picture of program.

  18. Hormone Therapy for Breast Cancer in Men

    Science.gov (United States)

    ... Topic Targeted therapy for breast cancer in men Hormone therapy for breast cancer in men Hormone therapy ... fatigue, and pain at the injection site. Luteinizing hormone-releasing hormone (LHRH) analogs and anti-androgens LHRH ...

  19. [Hormonal contraception in autoimmpne diseases].

    Science.gov (United States)

    Matyszkiewicz, Anna; Jach, Robert; Rajtar-Ciosek, Agnieszka; Basta, Tomasz

    2016-01-01

    The onset and the course of autoimmune diseases is influenced among other factors by the sex hormones. Hormonal contraception might affect the course of the autoimmune disease. The paper summarises the manner of save application of hormonal contraception in patients with autoimmune disease. PMID:27526427

  20. Growth Hormone: Use and Abuse

    Science.gov (United States)

    ... is huma n gr owth hormone? Human growth hormone (GH) is a substance that controls your body’s growth. ... prescribed for the FDA-approved conditions. In children, GH is used to treat • Growth hormone deficiency • Conditions that cause short stature (being shorter ...

  1. Transmastoid reshaping of the sigmoid sinus: preliminary study of a novel surgical method to quiet pulsatile tinnitus of an unrecognized vascular origin.

    Science.gov (United States)

    Kim, Chong Sun; Kim, So Young; Choi, Hyunseok; Koo, Ja-Won; Yoo, Shin-Young; An, Gwang Seok; Lee, Kyogu; Choi, Inyong; Song, Jae-Jin

    2016-08-01

    OBJECTIVE A dominant sigmoid sinus with focal dehiscence or thinning (DSSD/T) of the overlying bony wall is a commonly encountered, but frequently overlooked, cause of vascular pulsatile tinnitus (VPT). Also, the pathophysiological mechanism of sound perception in patients with VPT remains poorly understood. In the present study, a novel surgical method, termed transmastoid SS-reshaping surgery, was introduced to ameliorate VPT in patients with DSSD/T. The authors reviewed a case series, analyzed the surgical outcomes, and suggested the pathophysiological mechanism of sound perception. The theoretical background underlying VPT improvement after transmastoid SS-reshaping surgery was also explored. METHODS Eight patients with VPT that was considered attributable to DSSD/T underwent transmastoid SS-reshaping surgery between February 2010 and February 2015. The mean postoperative follow-up period was 9.5 months (range 4-13 months). Transmastoid SS-reshaping surgery featured simple mastoidectomy, partial compression of the SS using harvested cortical bone chips, and reinforcement of the bony SS wall with bone cement. Perioperative medical records, imaging results, and audiological findings were comprehensively reviewed. RESULTS In 7 of the 8 patients (87.5%), the VPT abated immediately after surgery. Statistically significant improvements in tinnitus loudness and distress were evident on numeric rating scales. Three patients with preoperative ipsilesional low-frequency hearing loss exhibited postoperative improvements in their low-frequency hearing thresholds. No major postoperative complications were encountered except in the first subject, who experienced increased intracranial pressure postoperatively. This subsided after a revision operation for partial decompression of the SS. CONCLUSIONS Transmastoid SS-reshaping surgery may be a good surgical option in patients with DSSD/T, a previously unrecognized cause of VPT. Redistribution of severely asymmetrical blood flow

  2. A quantitative study of CSF pulsatile flow in normal pressure hydrocephalus; An analysis of flow patterns before and after a shunting procedure using cine MR phase imaging

    Energy Technology Data Exchange (ETDEWEB)

    Katayama, Shinji; Makabe, Tetsuo; Itoh, Takahiko (Okayama Univ. (Japan). School of Medicine) (and others)

    1992-06-01

    In the previous report, we described the visualization and quantitative analysis of a normal CSF pulsatile flow using cine MR phase imaging. In the present study, CSF flow velocities were measured in patients with normal pressure hydrocephalus (NPH) before and after a shunting procedure. All of the healthy subjects showed a similar flow pattern in the time-velocity flow profiles (TVFP). However, patients with NPH showed a variable pattern of TVFP and could be divided into the following four types: Type 0: the CSF flow pattern was similar to that of the healthy subjects. Type I: the caudal peak flow was delayed more than 190 msec on TVFP. Type II: the caudal peak flow was not apparent, but the CSF flow through the aqueduct was remarkable on phase images. Type III: the amplitude of TVFP was very small, and no CSF flow through the aqueduct was identified. The patients with Type III TVFP showed significantly lower NPH scores. The lumbar CSF pressures tended to be high in the patients with Type III TVFP, but nevertheless failed to reach a statistically significant level. The amplitude of TVFP increased in the patients who improved clinically after the shunting procedure. Some of the Type III patients changed into Type II, I, and 0; also, one of the Type II patients changed into a Type I patients after the shunting procedure. We conclude that cine MR phase imaging is useful for analyzing the CSF flow of the patients with NPH before and after the shunting procedure as well as for evaluating shunt patency. (author).

  3. Total organic carbon analyzer

    Science.gov (United States)

    Godec, Richard G.; Kosenka, Paul P.; Smith, Brian D.; Hutte, Richard S.; Webb, Johanna V.; Sauer, Richard L.

    1991-01-01

    The development and testing of a breadboard version of a highly sensitive total-organic-carbon (TOC) analyzer are reported. Attention is given to the system components including the CO2 sensor, oxidation reactor, acidification module, and the sample-inlet system. Research is reported for an experimental reagentless oxidation reactor, and good results are reported for linearity, sensitivity, and selectivity in the CO2 sensor. The TOC analyzer is developed with gravity-independent components and is designed for minimal additions of chemical reagents. The reagentless oxidation reactor is based on electrolysis and UV photolysis and is shown to be potentially useful. The stability of the breadboard instrument is shown to be good on a day-to-day basis, and the analyzer is capable of 5 sample analyses per day for a period of about 80 days. The instrument can provide accurate TOC and TIC measurements over a concentration range of 20 ppb to 50 ppm C.

  4. Bedside assistance in freehand ultrasonic diagnosis by real-time visual feedback of 3D scatter diagram of pulsatile tissue-motion

    Science.gov (United States)

    Fukuzawa, M.; Kawata, K.; Nakamori, N.; Kitsunezuka, Y.

    2011-03-01

    By real-time visual feedback of 3D scatter diagram of pulsatile tissue-motion, freehand ultrasonic diagnosis of neonatal ischemic diseases has been assisted at the bedside. The 2D ultrasonic movie was taken with a conventional ultrasonic apparatus (ATL HDI5000) and ultrasonic probes of 5-7 MHz with the compact tilt-sensor to measure the probe orientation. The real-time 3D visualization was realized by developing an extended version of the PC-based visualization system. The software was originally developed on the DirectX platform and optimized with the streaming SIMD extensions. The 3D scatter diagram of the latest pulsatile tissues has been continuously generated and visualized as projection image with the ultrasonic movie in the current section more than 15 fps. It revealed the 3D structure of pulsatile tissues such as middle and posterior cerebral arteries, Willis ring and cerebellar arteries, in which pediatricians have great interests in the blood flow because asphyxiated and/or low-birth-weight neonates have a high risk of ischemic diseases such as hypoxic-ischemic encephalopathy and periventricular leukomalacia. Since the pulsatile tissue-motion is due to local blood flow, it can be concluded that the system developed in this work is very useful to assist freehand ultrasonic diagnosis of ischemic diseases in the neonatal cranium.

  5. Analyzing radioligand binding data.

    Science.gov (United States)

    Motulsky, Harvey; Neubig, Richard

    2002-08-01

    Radioligand binding experiments are easy to perform, and provide useful data in many fields. They can be used to study receptor regulation, discover new drugs by screening for compounds that compete with high affinity for radioligand binding to a particular receptor, investigate receptor localization in different organs or regions using autoradiography, categorize receptor subtypes, and probe mechanisms of receptor signaling, via measurements of agonist binding and its regulation by ions, nucleotides, and other allosteric modulators. This unit reviews the theory of receptor binding and explains how to analyze experimental data. Since binding data are usually best analyzed using nonlinear regression, this unit also explains the principles of curve fitting with nonlinear regression.

  6. Pulsatile compared with nonpulsatile perfusion using a centrifugal pump for cardiopulmonary bypass during coronary artery bypass grafting. Effects on systemic haemodynamics, oxygenation, and inflammatory response parameters.

    Science.gov (United States)

    Driessen, J J; Dhaese, H; Fransen, G; Verrelst, P; Rondelez, L; Gevaert, L; van Becelaere, M; Schelstraete, E

    1995-01-01

    The present study investigated the influence of pulsatile or nonpulsatile flow delivery with a centrifugal pump for cardiopulmonary bypass (CPB) during coronary artery bypass grafting (CABG) in two randomized groups of 19 patients each. All patients received a standard anaesthetic and surgical protocol. Pulsatile perfusion during CPB was created by accelerating the baseline pump speed of the Sarns centrifugal pump at a rate of 50 cycles per minute. Measurements included perioperative systemic haemodynamics and oxygen exchange, total haemolytic complement (CH50), polymorphonuclear (neutrophil) granulocyte (PMN) count and plasma granulocyte elastase bound to alpha 1-proteinase inhibitor (E-alpha 1-PI). Laboratory measurements were corrected for haemodilution. During and after CPB there were only a few significant differences between the groups in systemic haemodynamics and oxygenation, i.e. a lower mean arterial blood pressure after the end of CPB in the nonpulsatile group (65 mmHg, SD = 11 vs 76 mmHg, SD = 11) and a lower SvO2 during rewarming on CPB in the nonpulsatile group (62%, SD = 8 vs 67%, SD = 8). The decrease in percentage of PMNs in the total white blood cell count during CPB was greater in the nonpulsatile group than in the pulsatile group (from 61 to 46% vs 63 to 53% of prebypass value). The steep increase of PMN count at the end of CPB and postoperatively was comparable in both groups. The maximal decrease of CH50 levels, occurring after surgery, was significantly higher in the nonpulsatile group (70% SD = 15 vs 79%, SD = 16, of baseline value), suggesting a greater complement activation. E-alpha 1-PI levels increased significantly in both groups during and after CPB with higher peak levels, obtained at one hour after admission to an intensive care unit, in the nonpulsatile group (316 micrograms/l, SD = 102) than in the pulsatile group (247 micrograms/l, SD = 106). There was a partly inverse correlation between the peak postoperative elastase levels and

  7. Gastrointestinal hormones and their targets

    DEFF Research Database (Denmark)

    Rehfeld, Jens F.

    2014-01-01

    , paracrine, spermiocrine secretion etc.), so the same peptide may act as a blood-borne hormone, a neurotransmitter, a local growth factor, or a fertility factor. The molecular targets of each bioactive peptide are specific G-protein coupled receptors expressed in the cell membranes of different target cells......Gastrointestinal hormones are peptides released from endocrine cells and neurons in the digestive tract. More than 30 hormone genes are currently known to be expressed in the gastrointestinal tract, which makes the gut the largest hormone producing organ in the body. Modern biology makes...... it feasible to conceive the hormones under five headings: The structural homology groups a majority of the hormones into nine families, each of which is assumed to originate from one ancestral gene. The individual hormone gene often has multiple phenotypes due to alternative splicing, tandem organization...

  8. Biosimilar growth hormone.

    Science.gov (United States)

    Saenger, Paul

    2012-01-01

    As the first wave of biopharmaceuticals is expiring, biosimilars or follow-on -protein products (FOPP's) have emerged. Biosimilar drugs are cheaper than the originator/comparator drug. The regulatory foundation for these products is more advanced and better codified in Europe than in the US. Biosimilar soamtropin has been approved in both the US and Europe. The scientific viability of biosimilar drugs and especially growth hormone has been proven by several rigorously conducted clinical trials. Efficacy and safety data (growth rates, IGF-1 generation) for up to 7 y for pediatric indications measure up favorably to previously approved growth hormones which served as reference comparators. The Obama Administration appears to be committed to establish innovative pathways for the approval of biologics and biosimilars in the US. The cost savings in health care expenditures will be substantial as the global sales of biologics have reached $ 93 billion in 2009.

  9. Hormones in pregnancy

    Directory of Open Access Journals (Sweden)

    Pratap Kumar

    2012-01-01

    Full Text Available The endocrinology of human pregnancy involves endocrine and metabolic changes that result from physiological alterations at the boundary between mother and fetus. Progesterone and oestrogen have a great role along with other hormones. The controversies of use of progestogen and others are discussed in this chapter. Progesterone has been shown to stimulate the secretion of Th2 and reduces the secretion of Th1 cytokines which maintains pregnancy. Supportive care in early pregnancy is associated with a significant beneficial effect on pregnancy outcome. Prophylactic hormonal supplementation can be recommended for all assisted reproduction techniques cycles. Preterm labor can be prevented by the use of progestogen. The route of administration plays an important role in the drug′s safety and efficacy profile in different trimesters of pregnancy. Thyroid disorders have a great impact on pregnancy outcome and needs to be monitored and treated accordingly. Method of locating review: Pubmed, scopus

  10. Analyzing Workforce Education. Monograph.

    Science.gov (United States)

    Texas Community & Technical Coll. Workforce Education Consortium.

    This monograph examines the issue of task analysis as used in workplace literacy programs, debating the need for it and how to perform it in a rapidly changing environment. Based on experiences of community colleges in Texas, the report analyzes ways that task analysis can be done and how to implement work force education programs more quickly.…

  11. List mode multichannel analyzer

    Science.gov (United States)

    Archer, Daniel E.; Luke, S. John; Mauger, G. Joseph; Riot, Vincent J.; Knapp, David A.

    2007-08-07

    A digital list mode multichannel analyzer (MCA) built around a programmable FPGA device for onboard data analysis and on-the-fly modification of system detection/operating parameters, and capable of collecting and processing data in very small time bins (<1 millisecond) when used in histogramming mode, or in list mode as a list mode MCA.

  12. Centrifugal analyzer development

    International Nuclear Information System (INIS)

    The development of the centrifuge fast analyzer (CFA) is reviewed. The development of a miniature CFA with computer data analysis is reported and applications for automated diagnostic chemical and hematological assays are discussed. A portable CFA system with microprocessor was adapted for field assays of air and water samples for environmental pollutants, including ammonia, nitrates, nitrites, phosphates, sulfates, and silica. 83 references

  13. Analyzing business models

    DEFF Research Database (Denmark)

    Nielsen, Christian

    2014-01-01

    , because the costs of processing and analyzing it exceed the benefits indicating bounded rationality. Hutton (2002) concludes that the analyst community’s inability to raise important questions on quality of management and the viability of its business model inevitably led to the Enron debacle. There seems...

  14. 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.

  15. Hormones in pregnancy

    OpenAIRE

    Pratap Kumar; Navneet Magon

    2012-01-01

    The endocrinology of human pregnancy involves endocrine and metabolic changes that result from physiological alterations at the boundary between mother and fetus. Progesterone and oestrogen have a great role along with other hormones. The controversies of use of progestogen and others are discussed in this chapter. Progesterone has been shown to stimulate the secretion of Th2 and reduces the secretion of Th1 cytokines which maintains pregnancy. Supportive care in early pregnancy is associated...

  16. The wound hormone jasmonate

    OpenAIRE

    Koo, Abraham J.K.; Howe, Gregg A.

    2009-01-01

    Plant tissues are highly vulnerable to injury by herbivores, pathogens, mechanical stress, and other environmental insults. Optimal plant fitness in the face of these threats relies on complex signal transduction networks that link damage-associated signals to appropriate changes in metabolism, growth, and development. Many of these wound-induced adaptive responses are triggered by de novo synthesis of the plant hormone jasmonate (JA). Recent studies provide evidence that JA mediates systemic...

  17. Lear CAN analyzer

    OpenAIRE

    Peiró Ibañez, Felipe

    2013-01-01

    Since it was introduced in the automotive industry, the protocol CAN (Controller Area Network) has been widely used for its benefits. This has led many companies to offer several hardware and software solutions in order to monitor the communications that gives this protocol. The current master thesis presents the Lear CAN Analyzer as a software tool developed within the company LEAR Corporation. It is designed to be used in the automobile industry as a complement or substitute for other co...

  18. Analyzing business process management

    OpenAIRE

    Skjæveland, Børge

    2013-01-01

    Within the Oil & Gas Industry, the market is constantly growing more competitive, forcing companies to continually adapt to changes. Companies need to cut costs and improve the business efficiency. One way of successfully managing these challenges is to implement business process management in the organization. This thesis will analyze how Oceaneering Asset Integrity AS handled the implementation of a Business Process Management System and the effects it had on the employees. The main goal...

  19. Radioisotope analyzer of barium

    International Nuclear Information System (INIS)

    Principle of operation and construction of radioisotope barium sulphate analyzer type MZB-2 for fast determination of barium sulphate content in barite ores and enrichment products are described. The gauge equipped with Am-241 and a scintillation detector enables measurement of barium sulphate content in prepared samples of barite ores in the range 60% - 100% with the accuracy of 1%. The gauge is used in laboratories of barite mine and ore processing plant. 2 refs., 2 figs., 1 tab. (author)

  20. IPv6 Protocol Analyzer

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    With the emerging of next generation Intemet protocol (IPv6), it is expected to replace the current version of Internet protocol (IPv4) that will be exhausted in the near future. Besides providing adequate address space, some other new features are included into the new 128 bits of IP such as IP auto configuration, quality of service, simple routing capability, security, mobility and multicasting. The current protocol analyzer will not be able to handle IPv6 packets. This paper will focus on developing protocol analyzer that decodes IPv6 packet. IPv6 protocol analyzer is an application module,which is able to decode the IPv6 packet and provide detail breakdown of the construction of the packet. It has to understand the detail construction of the IPv6, and provide a high level abstraction of bits and bytes of the IPv6 packet.Thus it increases network administrators' understanding of a network protocol,helps he/she in solving protocol related problem in a IPv6 network environment.

  1. An efficient approach to study the pulsatile blood flow in femoral and coronary arteries by Differential Quadrature Method

    Science.gov (United States)

    Ghasemi, Seiyed E.; Hatami, M.; Hatami, J.; Sahebi, S. A. R.; Ganji, D. D.

    2016-02-01

    In this paper, flow analysis for a non-Newtonian third grade blood in coronary and femoral arteries is simulated numerically. Blood is considered as the third grade non-Newtonian fluid under periodic body acceleration motion and pulsatile pressure gradient. Differential Quadrature Method (DQM) and Crank Nicholson Method (CNM) are used to solve the Partial Differential Equation (PDE) governing equation by which a good agreement between them was observed in the results. The influences of some physical parameters such as amplitude, lead angle and body acceleration frequency on non-dimensional velocity and profiles are considered. For instance, the results show that increasing the amplitude, Ag, and reducing the lead angle of body acceleration, ϕ, make higher velocity profiles in the center line of both arteries.

  2. 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.

  3. Fluorescence analyzer for lignin

    Science.gov (United States)

    Berthold, John W.; Malito, Michael L.; Jeffers, Larry

    1993-01-01

    A method and apparatus for measuring lignin concentration in a sample of wood pulp or black liquor comprises a light emitting arrangement for emitting an excitation light through optical fiber bundles into a probe which has an undiluted sensing end facing the sample. The excitation light causes the lignin concentration to produce fluorescent emission light which is then conveyed through the probe to analyzing equipment which measures the intensity of the emission light. Measures a This invention was made with Government support under Contract Number DOE: DE-FC05-90CE40905 awarded by the Department of Energy (DOE). The Government has certain rights in this invention.

  4. Analyzing Chinese Financial Reporting

    Institute of Scientific and Technical Information of China (English)

    SABRINA; ZHANG

    2008-01-01

    If the world’s capital markets could use a harmonized accounting framework it would not be necessary for a comparison between two or more sets of accounting standards. However,there is much to do before this becomes reality.This article aims to pres- ent a general overview of China’s General Accepted Accounting Principles(GAAP), U.S.General Accepted Accounting Principles and International Financial Reporting Standards(IFRS),and to analyze the differ- ences among IFRS,U.S.GAAP and China GAAP using fixed assets as an example.

  5. Ring Image Analyzer

    Science.gov (United States)

    Strekalov, Dmitry V.

    2012-01-01

    Ring Image Analyzer software analyzes images to recognize elliptical patterns. It determines the ellipse parameters (axes ratio, centroid coordinate, tilt angle). The program attempts to recognize elliptical fringes (e.g., Newton Rings) on a photograph and determine their centroid position, the short-to-long-axis ratio, and the angle of rotation of the long axis relative to the horizontal direction on the photograph. These capabilities are important in interferometric imaging and control of surfaces. In particular, this program has been developed and applied for determining the rim shape of precision-machined optical whispering gallery mode resonators. The program relies on a unique image recognition algorithm aimed at recognizing elliptical shapes, but can be easily adapted to other geometric shapes. It is robust against non-elliptical details of the image and against noise. Interferometric analysis of precision-machined surfaces remains an important technological instrument in hardware development and quality analysis. This software automates and increases the accuracy of this technique. The software has been developed for the needs of an R&TD-funded project and has become an important asset for the future research proposal to NASA as well as other agencies.

  6. Field Deployable DNA analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Wheeler, E; Christian, A; Marion, J; Sorensen, K; Arroyo, E; Vrankovich, G; Hara, C; Nguyen, C

    2005-02-09

    This report details the feasibility of a field deployable DNA analyzer. Steps for swabbing cells from surfaces and extracting DNA in an automatable way are presented. Since enzymatic amplification reactions are highly sensitive to environmental contamination, sample preparation is a crucial step to make an autonomous deployable instrument. We perform sample clean up and concentration in a flow through packed bed. For small initial samples, whole genome amplification is performed in the packed bed resulting in enough product for subsequent PCR amplification. In addition to DNA, which can be used to identify a subject, protein is also left behind, the analysis of which can be used to determine exposure to certain substances, such as radionuclides. Our preparative step for DNA analysis left behind the protein complement as a waste stream; we determined to learn if the proteins themselves could be analyzed in a fieldable device. We successfully developed a two-step lateral flow assay for protein analysis and demonstrate a proof of principle assay.

  7. A nonpeptidyl growth hormone secretagogue.

    Science.gov (United States)

    Smith, R G; Cheng, K; Schoen, W R; Pong, S S; Hickey, G; Jacks, T; Butler, B; Chan, W W; Chaung, L Y; Judith, F

    1993-06-11

    A nonpeptidyl secretagogue for growth hormone of the structure 3-amino-3-methyl-N-(2,3,4,5-tetrahydro-2-oxo-1-([2'-(1H-tetrazol-5 -yl) (1,1'-biphenyl)-4-yl]methyl)-1H-1-benzazepin-3(R)-yl)-butanamid e (L-692,429) has been identified. L-692,429 synergizes with the natural growth hormone secretagogue growth hormone-releasing hormone and acts through an alternative signal transduction pathway. The mechanism of action of L-692,429 and studies with peptidyl and nonpeptidyl antagonists suggest that this molecule is a mimic of the growth hormone-releasing hexapeptide His-D-Trp-Ala-Trp-D-Phe-Lys-NH2 (GHRP-6). L-692,429 is an example of a nonpeptidyl specific secretagogue for growth hormone.

  8. Quo vadis plant hormone analysis?

    OpenAIRE

    Tarkowská, D. (Danuše); Novák, O. (Ondřej); Floková, K. (Kristýna); Tarkowski, P.; Turečková, V. (Veronika); Grúz, J. (Jiří); Rolčík, J. (Jakub); Strnad, M.

    2014-01-01

    Plant hormones act as chemical messengers in the regulation of myriads of physiological processes that occur in plants. To date, nine groups of plant hormones have been identified and more will probably be discovered. Furthermore, members of each group may participate in the regulation of physiological responses in planta both alone and in concert with members of either the same group or other groups. The ideal way to study biochemical processes involving these signalling molecules is 'hormon...

  9. Mammalian sex hormones in plants

    OpenAIRE

    Andrzej Skoczowski; Anna Janeczko

    2011-01-01

    The occurrence of mammalian sex hormones and their physiological role in plants is reviewed. These hormones, such as 17β-estradiol, androsterone, testosterone or progesterone, were present in 60-80% of the plant species investigated. Enzymes responsible for their biosynthesis and conversion were also found in plants. Treatment of the plants with sex hormones or their precursors influenced plant development: cell divisions, root and shoot growth, embryo growth, flowering, pollen tube ...

  10. Hormones and Borderline Personality Features

    OpenAIRE

    Evardone, Milagros; Alexander, Gerianne M.; Morey, Leslie C.

    2008-01-01

    Borderline personality is diagnosed in clinical settings three times more often in women than in men, and symptom severity in women appears sensitive to circulating sex steroid levels. In non-human mammals, prenatal hormones contribute to the development of sex-linked behavior and their responsiveness to postnatal hormones. Therefore, this study examined the hypothesis that prenatal hormones may influence the development of borderline personality traits by measuring a marker of perinatal andr...

  11. Growth hormone and aging

    OpenAIRE

    Bartke, Andrzej; Brown-Borg, Holly; Kinney, Beth; Mattison, Julie; Wright, Chris; Hauck, Steven; Coschigano, Karen; Kopchick, John

    2000-01-01

    The potential usefulness of growth hormone (GH) as an anti-aging therapy is of considerable current interest. Secretion of GH normally declines during aging and administration of GH can reverse age-related changes in body composition. However, mutant dwarf mice with congenital GH deficiency and GH resistant GH-R-KO mice live much longer than their normal siblings, while a pathological elevation of GH levels reduces life expectancy in both mice and men. We propose that the actions of GH on gro...

  12. Residual gas analyzer calibration

    Science.gov (United States)

    Lilienkamp, R. H.

    1972-01-01

    A technique which employs known gas mixtures to calibrate the residual gas analyzer (RGA) is described. The mass spectra from the RGA are recorded for each gas mixture. This mass spectra data and the mixture composition data each form a matrix. From the two matrices the calibration matrix may be computed. The matrix mathematics requires the number of calibration gas mixtures be equal to or greater than the number of gases included in the calibration. This technique was evaluated using a mathematical model of an RGA to generate the mass spectra. This model included shot noise errors in the mass spectra. Errors in the gas concentrations were also included in the valuation. The effects of these errors was studied by varying their magnitudes and comparing the resulting calibrations. Several methods of evaluating an actual calibration are presented. The effects of the number of gases in then, the composition of the calibration mixture, and the number of mixtures used are discussed.

  13. Analyzing architecture articles

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    In the present study, we express the quality, function, and characteristics of architecture to help people comprehensively understand what architecture is. We also reveal the problems and conflict found in population, land, water resources, pollution, energy, and the organization systems in construction. China’s economy is transforming. We should focus on the cities, architectural environment, energy conservation, emission-reduction, and low-carbon output that will result in successful green development. We should macroscopically and microscopically analyze the development, from the natural environment to the artificial environment; from the relationship between human beings and nature to the combination of social ecology in cities, and farmlands. We must learn to develop and control them harmoniously and scientifically to provide a foundation for the methods used in architecture research.

  14. PDA: Pooled DNA analyzer

    Directory of Open Access Journals (Sweden)

    Lin Chin-Yu

    2006-04-01

    Full Text Available Abstract Background Association mapping using abundant single nucleotide polymorphisms is a powerful tool for identifying disease susceptibility genes for complex traits and exploring possible genetic diversity. Genotyping large numbers of SNPs individually is performed routinely but is cost prohibitive for large-scale genetic studies. DNA pooling is a reliable and cost-saving alternative genotyping method. However, no software has been developed for complete pooled-DNA analyses, including data standardization, allele frequency estimation, and single/multipoint DNA pooling association tests. This motivated the development of the software, 'PDA' (Pooled DNA Analyzer, to analyze pooled DNA data. Results We develop the software, PDA, for the analysis of pooled-DNA data. PDA is originally implemented with the MATLAB® language, but it can also be executed on a Windows system without installing the MATLAB®. PDA provides estimates of the coefficient of preferential amplification and allele frequency. PDA considers an extended single-point association test, which can compare allele frequencies between two DNA pools constructed under different experimental conditions. Moreover, PDA also provides novel chromosome-wide multipoint association tests based on p-value combinations and a sliding-window concept. This new multipoint testing procedure overcomes a computational bottleneck of conventional haplotype-oriented multipoint methods in DNA pooling analyses and can handle data sets having a large pool size and/or large numbers of polymorphic markers. All of the PDA functions are illustrated in the four bona fide examples. Conclusion PDA is simple to operate and does not require that users have a strong statistical background. The software is available at http://www.ibms.sinica.edu.tw/%7Ecsjfann/first%20flow/pda.htm.

  15. [Hormone replacement therapy--growth hormone, melatonin, DHEA and sex hormones].

    Science.gov (United States)

    Fukai, Shiho; Akishita, Masahiro

    2009-07-01

    The ability to maintain active and independent living as long as possible is crucial for the healthy longevity. Hormones responsible for some of the manifestations associated with aging are growth hormone, insulin-like growth factor-1 (IGF-1), melatonin, dehydroepiandrosterone (DHEA), sex hormones and thyroid hormones. These hormonal changes are associated with changes in body composition, visceral obesity, muscle weakness, osteoporosis, urinary incontinence, loss of cognitive functioning, reduction in well being, depression, as well as sexual dysfunction. With the prolongation of life expectancy, both men and women today live the latter third life with endocrine deficiencies. Hormone replacement therapy may alleviate the debilitating conditions of secondary partial endocrine deficiencies by preventing or delaying some aspects of aging.

  16. Pseudostupidity and analyzability.

    Science.gov (United States)

    Cohn, L S

    1989-01-01

    This paper seeks to heighten awareness of pseudostupidity and the potential analyzability of patients who manifest it by defining and explicating it, reviewing the literature, and presenting in detail the psychoanalytic treatment of a pseudostupid patient. Pseudostupidity is caused by an inhibition of the integration and synthesis of thoughts resulting in a discrepancy between intellectual capacity and apparent intellect. The patient's pseudostupidity was determined in part by his need to prevent his being more successful than father, i.e., defeating his oedipal rival. Knowing and learning were instinctualized. The patient libidinally and defensively identified with father's passive, masochistic position. He needed to frustrate the analyst as he had felt excited and frustrated by his parents' nudity and thwarted by his inhibitions. He wanted to cause the analyst to feel as helpless as he, the patient, felt. Countertransference frustration was relevant and clinically useful in the analysis. Interpretation of evolving relevant issues led to more anxiety and guilt, less pseudostupidity, a heightened alliance, and eventual working through. Negative therapeutic reactions followed the resolution of pseudostupidity. PMID:2708771

  17. Downhole Fluid Analyzer Development

    Energy Technology Data Exchange (ETDEWEB)

    Bill Turner

    2006-11-28

    A novel fiber optic downhole fluid analyzer has been developed for operation in production wells. This device will allow real-time determination of the oil, gas and water fractions of fluids from different zones in a multizone or multilateral completion environment. The device uses near infrared spectroscopy and induced fluorescence measurement to unambiguously determine the oil, water and gas concentrations at all but the highest water cuts. The only downhole components of the system are the fiber optic cable and windows. All of the active components--light sources, sensors, detection electronics and software--will be located at the surface, and will be able to operate multiple downhole probes. Laboratory testing has demonstrated that the sensor can accurately determine oil, water and gas fractions with a less than 5 percent standard error. Once installed in an intelligent completion, this sensor will give the operating company timely information about the fluids arising from various zones or multilaterals in a complex completion pattern, allowing informed decisions to be made on controlling production. The research and development tasks are discussed along with a market analysis.

  18. Analyzing Spacecraft Telecommunication Systems

    Science.gov (United States)

    Kordon, Mark; Hanks, David; Gladden, Roy; Wood, Eric

    2004-01-01

    Multi-Mission Telecom Analysis Tool (MMTAT) is a C-language computer program for analyzing proposed spacecraft telecommunication systems. MMTAT utilizes parameterized input and computational models that can be run on standard desktop computers to perform fast and accurate analyses of telecommunication links. MMTAT is easy to use and can easily be integrated with other software applications and run as part of almost any computational simulation. It is distributed as either a stand-alone application program with a graphical user interface or a linkable library with a well-defined set of application programming interface (API) calls. As a stand-alone program, MMTAT provides both textual and graphical output. The graphs make it possible to understand, quickly and easily, how telecommunication performance varies with variations in input parameters. A delimited text file that can be read by any spreadsheet program is generated at the end of each run. The API in the linkable-library form of MMTAT enables the user to control simulation software and to change parameters during a simulation run. Results can be retrieved either at the end of a run or by use of a function call at any time step.

  19. The role of kisspeptin and gonadotropin inhibitory hormone in the seasonal regulation of reproduction in sheep.

    Science.gov (United States)

    Smith, J T

    2012-08-01

    Sheep are seasonal breeders, experiencing an annual period of reproductive quiescence in response to increased photoperiod during the late-winter into spring and renaissance during the late summer. The nonbreeding (anestrous) season is characterized by a reduction in the pulsatile secretion of GnRH from the brain, in part because of an increase in negative feedback activity of estrogen. Neuronal populations in the hypothalamus that produce kisspeptin and gonadotropin-inhibitory hormone (GnIH) appear to be important for the seasonal shift in reproductive activity, and the former are also mandatory for puberty onset. Kisspeptin cells in the arcuate nucleus (ARC) and preoptic area appear to regulate GnRH neurons and transmit sex-steroid feedback signals to these neurons. Moreover, kisspeptin expression in the ARC is markedly up-regulated at the onset of the breeding season, as too are the number of kisspeptin fibers in close apposition to GnRH neurons. The lower levels of kisspeptin seen during the nonbreeding season can be "corrected" by infusion of kisspeptin, which causes ovulation in seasonally acyclic females. The role of GnIH is less clear, but mounting evidence supports a role for this neuropeptide in the inhibitory regulation of both GnRH secretion and gonadotropin release from the pituitary gland. Contrary to kisspeptin, GnIH expression is markedly reduced at the onset of the breeding season. In addition, the number of GnIH fibers in close apposition to GnRH neurons also decreases during this time. Importantly, exogenous GnIH treatment can block both the pulsatile release of LH and the preovulatory LH surge during the breeding season. In summary, it is most likely the integrated function of both these neuropeptide systems that modulate the annual shift in photoperiod to a physiological change in fertility.

  20. Sex hormones, sex hormone binding globulin, and vertebral fractures in older men.

    Science.gov (United States)

    Cawthon, Peggy M; Schousboe, John T; Harrison, Stephanie L; Ensrud, Kristine E; Black, Dennis; Cauley, Jane A; Cummings, Steven R; LeBlanc, Erin S; Laughlin, Gail A; Nielson, Carrie M; Broughton, Augusta; Kado, Deborah M; Hoffman, Andrew R; Jamal, Sophie A; Barrett-Connor, Elizabeth; Orwoll, Eric S

    2016-03-01

    The association between sex hormones and sex hormone binding globin (SHBG) with vertebral fractures in men is not well studied. In these analyses, we determined whether sex hormones and SHBG were associated with greater likelihood of vertebral fractures in a prospective cohort study of community dwelling older men. We included data from participants in MrOS who had been randomly selected for hormone measurement (N=1463, including 1054 with follow-up data 4.6years later). Major outcomes included prevalent vertebral fracture (semi-quantitative grade≥2, N=140, 9.6%) and new or worsening vertebral fracture (change in SQ grade≥1, N=55, 5.2%). Odds ratios per SD decrease in sex hormones and per SD increase in SHBG were estimated with logistic regression adjusted for potentially confounding factors, including age, bone mineral density, and other sex hormones. Higher SHBG was associated with a greater likelihood of prevalent vertebral fractures (OR: 1.38 per SD increase, 95% CI: 1.11, 1.72). Total estradiol analyzed as a continuous variable was not associated with prevalent vertebral fractures (OR per SD decrease: 0.86, 95% CI: 0.68 to 1.10). Men with total estradiol values ≤17pg/ml had a borderline higher likelihood of prevalent fracture than men with higher values (OR: 1.46, 95% CI: 0.99, 2.16). There was no association between total testosterone and prevalent fracture. In longitudinal analyses, SHBG (OR: 1.42 per SD increase, 95% CI: 1.03, 1.95) was associated with new or worsening vertebral fracture, but there was no association with total estradiol or total testosterone. In conclusion, higher SHBG (but not testosterone or estradiol) is an independent risk factor for vertebral fractures in older men.

  1. Radioimmunoassay of bovine, ovine and porcine luteinizing hormone with a monoclonal antibody and a human tracer

    International Nuclear Information System (INIS)

    A radioimmunoassay for bovine (bLH), ovine (oLH) and porcine (pLH) luteinizing hormone was developed using a human 125ILH tracer from a commercial kit and a monoclonal antibody (518B7) specific for LH but with low species specificity. Standard curves demonstrated similar binding kinetics when bLH, oLH and pLH were incubated with tracer and antibody for 2 h at room temperature. A 30-min delay in the addition of the tracer gave sufficient sensitivity when analysing pLH. Separation of antibody-bound LH from free hormone was achieved by using second antibody-coated micro Sepharose beads. The assay was validated and the performance compared with that of an RIA currently in use for determination of bLH (coefficient of correlation: 0.99 and 0.98). Regardless of the standards used, intra-assay coefficients of variation were <10% for LH concentrations exceeding 1 μg/L. The inter-assay coefficients of variation were <15%. The assay was used for clinical evaluation demonstrating the pre-ovulatory LH surge in two cyclic cows, LH pulsatility in an oophorectomized ewe and LH response to GnRH injection in a boar. (au) (7 refs.)

  2. Trial of Recombinant Follicle-Stimulating Hormone Pretreatment for GnRH-Induced Fertility in Patients with Congenital Hypogonadotropic Hypogonadism

    Science.gov (United States)

    Dwyer, Andrew A.; Sykiotis, Gerasimos P.; Hayes, Frances J.; Boepple, Paul A.; Lee, Hang; Loughlin, Kevin R.; Dym, Martin; Sluss, Patrick M.; Crowley, William F.

    2013-01-01

    Context and Objective: The optimal strategy for inducing fertility in men with congenital hypogonadotropic hypogonadism (CHH) is equivocal. Albeit a biologically plausible approach, pretreatment with recombinant FSH (rFSH) before GnRH/human chorionic gonadotropin administration has not been sufficiently assessed. The objective of the study was to test this method. Design and Setting: This was a randomized, open-label treatment protocol at an academic medical center. Patients and Interventions: GnRH-deficient men (CHH) with prepubertal testes (<4 mL), no cryptorchidism, and no prior gonadotropin therapy were randomly assigned to either 24 months of pulsatile GnRH therapy alone (inducing endogenous LH and FSH release) or 4 months of rFSH pretreatment followed by 24 months of GnRH therapy. Patients underwent serial testicular biopsies, ultrasound assessments of testicular volume, serum hormone measurements, and seminal fluid analyses. Results: rFSH treatment increased inhibin B levels into the normal range (from 29 ± 9 to 107 ± 41 pg/mL, P < .05) and doubled testicular volume (from 1.1 ± 0.2 to 2.2 ± 0.3 mL, P < .005). Histological analysis showed proliferation of both Sertoli cells (SCs) and spermatogonia, a decreased SC to germ cell ratio (from 0.74 to 0.35), and SC cytoskeletal rearrangements. With pulsatile GnRH, the groups had similar hormonal responses and exhibited significant testicular growth. All men receiving rFSH pretreatment developed sperm in their ejaculate (7 of 7 vs 4 of 6 in the GnRH-only group) and showed trends toward higher maximal sperm counts. Conclusions: rFSH pretreatment followed by GnRH is successful in inducing testicular growth and fertility in men with CHH with prepubertal testes. rFSH not only appears to maximize the SC population but also induces morphologic changes, suggesting broader developmental roles. PMID:24037890

  3. Digital Microfluidics Sample Analyzer

    Science.gov (United States)

    Pollack, Michael G.; Srinivasan, Vijay; Eckhardt, Allen; Paik, Philip Y.; Sudarsan, Arjun; Shenderov, Alex; Hua, Zhishan; Pamula, Vamsee K.

    2010-01-01

    Three innovations address the needs of the medical world with regard to microfluidic manipulation and testing of physiological samples in ways that can benefit point-of-care needs for patients such as premature infants, for which drawing of blood for continuous tests can be life-threatening in their own right, and for expedited results. A chip with sample injection elements, reservoirs (and waste), droplet formation structures, fluidic pathways, mixing areas, and optical detection sites, was fabricated to test the various components of the microfluidic platform, both individually and in integrated fashion. The droplet control system permits a user to control droplet microactuator system functions, such as droplet operations and detector operations. Also, the programming system allows a user to develop software routines for controlling droplet microactuator system functions, such as droplet operations and detector operations. A chip is incorporated into the system with a controller, a detector, input and output devices, and software. A novel filler fluid formulation is used for the transport of droplets with high protein concentrations. Novel assemblies for detection of photons from an on-chip droplet are present, as well as novel systems for conducting various assays, such as immunoassays and PCR (polymerase chain reaction). The lab-on-a-chip (a.k.a., lab-on-a-printed-circuit board) processes physiological samples and comprises a system for automated, multi-analyte measurements using sub-microliter samples of human serum. The invention also relates to a diagnostic chip and system including the chip that performs many of the routine operations of a central labbased chemistry analyzer, integrating, for example, colorimetric assays (e.g., for proteins), chemiluminescence/fluorescence assays (e.g., for enzymes, electrolytes, and gases), and/or conductometric assays (e.g., for hematocrit on plasma and whole blood) on a single chip platform.

  4. Alternatives of menopausal hormone therapy

    OpenAIRE

    Kutlešić Ranko M.; Popović Jasmina; Stefanović Milan; Vukomanović Predrag; Lukić Bojan; Lilić Goran

    2016-01-01

    Introduction. It has been generally accepted that the benefits of menopausal hormone therapy outweigh the risks, but there are still some concerns about the administration of menopausal hormone therapy, which has introduced alternative treatments. Pharmacological Alternatives. Central alpha-2 agonist clonidine is only marginally more effective than placebo, and significantly less effective than estrogen. Antiepileptic drug gabapentin reduces hot flashes; ho...

  5. Hormonal control of inflammatory responses

    Directory of Open Access Journals (Sweden)

    J. Garcia-Leme

    1993-01-01

    Full Text Available Almost any stage of inflammatory and immunological responses is affected by hormone actions. This provides the basis for the suggestion that hormones act as modulators of the host reaction against trauma and infection. Specific hormone receptors are detected in the reactive structures in inflamed areas and binding of hormone molecules to such receptors results in the generation of signals that influence cell functions relevant for the development of inflammatory responses. Diversity of hormonal functions accounts for recognized pro- and anti-inflammatory effects exerted by these substances. Most hormone systems are capable of influencing inflammatory events. Insulin and glucocorticoids, however, exert direct regulatory effects at concentrations usually found in plasma. Insulin is endowed with facilitatory actions on vascular reactivity to inflammatory mediators and inflammatory cell functions. Increased concentrations of circulating glucocorticoids at the early stages of inflammation results in downregulation of inflammatory responses. Oestrogens markedly reduce the response to injury in a variety of experimental models. Glucagon and thyroid hormones exert indirect anti-inflammatory effects mediated by the activity of the adrenal cortex. Accordingly, inflammation is not only merely a local response, but a hormone-controlled process.

  6. Measurement of the incretin hormones

    DEFF Research Database (Denmark)

    Kuhre, Rune Ehrenreich; Wewer Albrechtsen, Nicolai Jacob; Hartmann, Bolette;

    2015-01-01

    concentrations of GLP-1 and GIP is often an important endpoint in both clinical and preclinical studies and, therefore, accurate measurement of these hormones is important. Here, we provide an overview of current approaches for the measurement of the incretin hormones, with particular focus on immunological...

  7. Recent advances in hormonal contraception

    OpenAIRE

    Li, HW Raymond; Richard A. Anderson

    2010-01-01

    This report reviews some of the new studies regarding new hormonal contraceptive formulations (e.g., Yaz, Qlaira®, extended-cycle or continuous combined contraceptives, subcutaneous depot medroxyprogesterone acetate, and ulipristal acetate as an emergency contraceptive). Recent data on the relationship between hormonal contraceptive use and bone health are also reviewed. © 2010 Medicine Reports Ltd.

  8. Sex Hormones and Ischemic Stroke

    DEFF Research Database (Denmark)

    Holmegard, Haya N; Nordestgaard, Børge G; Jensen, Gorm B;

    2016-01-01

    CONTEXT AND OBJECTIVE: Whether endogenous sex hormones are associated with ischemic stroke (IS) is unclear. We tested the hypothesis that extreme concentrations of endogenous sex hormones are associated with risk of IS in the general population. DESIGN, SETTING, AND PARTICIPANTS: Adult men (n...

  9. Characterization of the hormone-binding domain of the chicken c-erbA/thyroid hormone receptor protein

    DEFF Research Database (Denmark)

    Muñoz, A; Zenke, M; Gehring, U;

    1988-01-01

    To identify and characterize the hormone-binding domain of the thyroid hormone receptor, we analyzed the ligand-binding capacities of proteins representing chimeras between the normal receptor and P75gag-v-erbA, the retrovirus-encoded form deficient in binding ligand. Our results show that severa......gag-v-erbA and that renders it biologically inactive fails to affect hormone binding by the c-erbA protein. These results suggest that the mutation changed the ability of P75gag-v-erbA to affect transcription since it also had no effect on DNA binding. Our data also suggest that hormone......-independent activity of P75gag-v-erbA provided a selective advantage to the avian erythroblastosis virus during the original selection for a highly oncogenic strain of the virus....

  10. Crew Activity Analyzer

    Science.gov (United States)

    Murray, James; Kirillov, Alexander

    2008-01-01

    The crew activity analyzer (CAA) is a system of electronic hardware and software for automatically identifying patterns of group activity among crew members working together in an office, cockpit, workshop, laboratory, or other enclosed space. The CAA synchronously records multiple streams of data from digital video cameras, wireless microphones, and position sensors, then plays back and processes the data to identify activity patterns specified by human analysts. The processing greatly reduces the amount of time that the analysts must spend in examining large amounts of data, enabling the analysts to concentrate on subsets of data that represent activities of interest. The CAA has potential for use in a variety of governmental and commercial applications, including planning for crews for future long space flights, designing facilities wherein humans must work in proximity for long times, improving crew training and measuring crew performance in military settings, human-factors and safety assessment, development of team procedures, and behavioral and ethnographic research. The data-acquisition hardware of the CAA (see figure) includes two video cameras: an overhead one aimed upward at a paraboloidal mirror on the ceiling and one mounted on a wall aimed in a downward slant toward the crew area. As many as four wireless microphones can be worn by crew members. The audio signals received from the microphones are digitized, then compressed in preparation for storage. Approximate locations of as many as four crew members are measured by use of a Cricket indoor location system. [The Cricket indoor location system includes ultrasonic/radio beacon and listener units. A Cricket beacon (in this case, worn by a crew member) simultaneously transmits a pulse of ultrasound and a radio signal that contains identifying information. Each Cricket listener unit measures the difference between the times of reception of the ultrasound and radio signals from an identified beacon

  11. Soft Decision Analyzer

    Science.gov (United States)

    Steele, Glen; Lansdowne, Chatwin; Zucha, Joan; Schlensinger, Adam

    2013-01-01

    The Soft Decision Analyzer (SDA) is an instrument that combines hardware, firmware, and software to perform realtime closed-loop end-to-end statistical analysis of single- or dual- channel serial digital RF communications systems operating in very low signal-to-noise conditions. As an innovation, the unique SDA capabilities allow it to perform analysis of situations where the receiving communication system slips bits due to low signal-to-noise conditions or experiences constellation rotations resulting in channel polarity in versions or channel assignment swaps. SDA s closed-loop detection allows it to instrument a live system and correlate observations with frame, codeword, and packet losses, as well as Quality of Service (QoS) and Quality of Experience (QoE) events. The SDA s abilities are not confined to performing analysis in low signal-to-noise conditions. Its analysis provides in-depth insight of a communication system s receiver performance in a variety of operating conditions. The SDA incorporates two techniques for identifying slips. The first is an examination of content of the received data stream s relation to the transmitted data content and the second is a direct examination of the receiver s recovered clock signals relative to a reference. Both techniques provide benefits in different ways and allow the communication engineer evaluating test results increased confidence and understanding of receiver performance. Direct examination of data contents is performed by two different data techniques, power correlation or a modified Massey correlation, and can be applied to soft decision data widths 1 to 12 bits wide over a correlation depth ranging from 16 to 512 samples. The SDA detects receiver bit slips within a 4 bits window and can handle systems with up to four quadrants (QPSK, SQPSK, and BPSK systems). The SDA continuously monitors correlation results to characterize slips and quadrant change and is capable of performing analysis even when the

  12. Types of Cancer Treatment: Hormone Therapy

    Science.gov (United States)

    Describes how hormone therapy slows or stops the growth of breast and prostate cancers that use hormones to grow. Includes information about the types of hormone therapy and side effects that may happen.

  13. Genetics Home Reference: combined pituitary hormone deficiency

    Science.gov (United States)

    ... Genetics Home Health Conditions combined pituitary hormone deficiency combined pituitary hormone deficiency Enable Javascript to view the ... boxes. Print All Open All Close All Description Combined pituitary hormone deficiency is a condition that causes ...

  14. Leptin: a multifunctional hormone

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Leptin is the protein product encoded by the obese (ob)gene. It is a circulating hormone produced primarily by the adipose tissue. ob/ob mice with mutations of the gene encoding leptin become morbidly obese, infertile, hyperphagic, hypothermic,and diabetic. Since the cloning of leptin in 1994, our knowledge in body weight regulation and the role played by leptin has increased substantially. We now know that leptin signals through its receptor, OB-R, which is a member of the cytokine receptor superfamily. Leptin serves as an adiposity signal to inform the brain the adipose tissue mass in a negative feedback loop regulating food intake and energy expenditure. Leptin also plays important roles in angiogenesis, immune function, fertility, and bone formation. Humans with mutations in the gene encoding leptin are also morbidly obese and respond to leptin treatment,demonstrating that enhancing or inhibiting leptin's activities in vivo may have potential therapeutic benefits.

  15. Turbulence detection in a stenosed artery bifurcation by numerical simulation of pulsatile blood flow using the low-Reynolds number turbulence model.

    Science.gov (United States)

    Ghalichi, Farzan; Deng, Xiaoyan

    2003-01-01

    The pulsatile blood flow in a partially blocked artery is significantly altered as the flow regime changes through the cardiac cycle. This paper reports on the application of a low-Reynolds turbulence model for computation of physiological pulsatile flow in a healthy and stenosed carotid artery bifurcation. The human carotid artery was chosen since it has received much attention because atherosclerotic lesions are frequently observed. The Wilcox low-Re k-omega turbulence model was used for the simulation since it has proven to be more accurate in describing transition from laminar to turbulent flow. Using the FIDAP finite element code a validation showed very good agreement between experimental and numerical results for a steady laminar to turbulent flow transition as reported in a previous publication by the same authors. Since no experimental or numerical results were available in the literature for a pulsatile and turbulent flow regime, a comparison between laminar and low-Re turbulent calculations was made to further validate the turbulence model. The results of this study showed a very good agreement for velocity profiles and wall shear stress values for this imposed pulsatile laminar flow regime. To explore further the medical aspect, the calculations showed that even in a healthy or non-stenosed artery, small instabilities could be found at least for a portion of the pulse cycle and in different sections. The 40% and 55% diameter reduction stenoses did not significantly change the turbulence characteristics. Further results showed that the presence of 75% stenoses changed the flow properties from laminar to turbulent flow for a good portion of the cardiac pulse. A full 3D simulation with this low-Re-turbulence model, coupled with Doppler ultrasound, can play a significant role in assessing the degree of stenosis for cardiac patients with mild conditions.

  16. Pulsatile flow and heat transfer of a magneto-micropolar fluid through a stenosed artery under the influence of body acceleration

    OpenAIRE

    Shit, G. C.; Roy, M.

    2012-01-01

    With an aim to investigate the effect of externally imposed body acceleration and magnetic field on pulsatile flow of blood through an arterial segment having stenosis is under consideration in this paper. The flow of blood is presented by a unsteady micropolar fluid and the heat transfer characteristics have been taken into account. The non-linear equations that governing the flow are solved numerically using finite difference technique by employing a suitable coordinate transformation. The ...

  17. Dogmas and controversies in the handling of nitrogenous wastes: 5-HT2-like receptors are involved in triggering pulsatile urea excretion in the gulf toadfish, Opsanus beta.

    Science.gov (United States)

    McDonald, M Danielle; Walsh, Patrick J

    2004-05-01

    When injected arterially, serotonin (5-hydroxytryptamine; 5-HT) has been shown to elicit naturally sized urea pulse events in the gulf toadfish, Opsanus beta. The goal of the present study was to determine which 5-HT receptor(s) was involved in mediating this serotonergic stimulation of the pulsatile excretion mechanism. Toadfish were surgically implanted with caudal arterial catheters and intraperitoneal catheters and injected with either 8-OH-DPAT (1 micro mol kg(-1)), a selective 5-HT(1A) receptor agonist, alpha-methyl-5-HT (1 micro mol kg(-1)), a 5-HT(2) receptor agonist, or ketanserin, a 5-HT(2) receptor antagonist (0.01, 0.1, 1 and 10 micro mol kg(-1)) plus alpha-methyl-5-HT. 8-OH-DPAT injection did not mediate an increase in urea excretion, ruling out the involvement of 5-HT(1A) receptors in pulsatile excretion. However, within 5 min, alpha-methyl-5-HT injection caused an increase in the excretion of urea in >95% (N=27) of the fish injected, with an average pulse size of 652+/-102 micro mol N kg(-1) (N=26). With alpha-methyl-5-HT injection there was no corresponding increase in ammonia or [(3)H]PEG 4000 permeability. Urea pulses elicited by alpha-methyl-5-HT were inhibited in a dose-dependent fashion by the 5-HT(2) receptor antagonist ketanserin, which at low doses caused a significant inhibition of pulse size and at higher doses significantly inhibited the occurrence of pulsatile excretion altogether. However, neither 8-OH-DPAT nor alpha-methyl 5-HT injection had an effect on plasma cortisol or plasma urea concentrations. These findings suggest the involvement of a 5-HT(2)-like receptor in the regulation of pulsatile urea excretion. PMID:15143134

  18. Pre-Treatment Objective Diagnosis and Post-Treatment Outcome Evaluation in Patients with Vascular Pulsatile Tinnitus Using Transcanal Recording and Spectro-Temporal Analysis

    Science.gov (United States)

    Choi, Inyong; Koo, Ja-Won; Lee, Kyogu

    2016-01-01

    Objective Although vascular pulsatile tinnitus (VPT) has been classified as “objective”, VPT is not easily recognizable or documentable in most cases. In response to this, we have developed transcanal sound recording (TSR) and spectro-temporal analysis (STA) for the objective diagnosis of VPT. By refining our initial method, we were able to apply TSR/STA to post-treatment outcome evaluation, as well as pre-treatment objective diagnosis. Methods TSR was performed on seven VPT patients and five normal controls before and after surgical or interventional treatment. VPT was recorded using an inserted microphone with the subjects placed in both upright and supine positions with 1) a neutral head position, 2) head rotated to the tinnitus side, 3) head rotated to the non-tinnitus side, and 4) a neutral position with ipsi-lesional manual cervical compression. The recorded signals were analyzed in both time and time-frequency domains by performing a short-time Fourier transformation. Results The pre-treatment ear canal signals of all VPT patients demonstrated pulse-synchronous periodic structures and acoustic characteristics that were representative of their presumptive vascular pathologies, whereas those the controls exhibited smaller peaks and weak periodicities. Compared with the pre-treatment signals, the post-treatment signals exhibited significantly reduced peak- and root mean square amplitudes upon time domain analysis. Additionally, further sub-band analysis confirmed that the pulse-synchronous signal of all subjects was not identifiable after treatment and, in particular, that the signal decrement was statistically significant at low frequencies. Moreover, the post-treatment signals of the VPT subjects revealed no significant differences when compared to those of the control group. Conclusion We reconfirmed that the TSR/STA method is an effective modality to objectify VPT. In addition, the potential role of the TSR/STA method in the objective evaluation of

  19. GnRH脉冲治疗对男性垂体柄中断综合征患者垂体-睾丸轴功能的影响%Effect of pulsatile GnRH therapy on pituitary-testicular axis function in male patients with pituitary stalk interruption syndrome

    Institute of Scientific and Technical Information of China (English)

    郑俊杰; 茅江峰; 伍学焱; 王曦; 刘兆祥; 黄炳昆

    2016-01-01

    Objective To evaluate the efficacy of pulsatile gonadotropin-releasing hormone(GnRH) therapy in male patients with pituitary stalk interruption syndrome (PSIS).Methods Fourteen male PSIS patients,who had received subcutaneous pulsatile GnRH therapy for at least four weeks at Peking Union Medical College Hospital from April 2014 to September 2015,were included in the study.Serum luteinizing hormone (LH),follicle-stimulating hormone (FSH),testosterone level,testicular volume and sperm in ejaculation were measured.After treatment for four weeks,subjects with serum LH ≥ 1.24 U/L were classified as "good response group",and others were classified as "poor response group".Results All patients were born by breech delivery and presented with absent pubertal development.Laboratory findings showed combined pituitary hormone deficiency in all patients.Pituitary stalk interruption syndrome was diagnosed based on MRI findings.Totally 11 out of 14 patients showed good response to pulsatile GnRH therapy.Their LH level increased from 0.32 (0.15,0.61) U/L to 4.34 (2.52,7.39) U/L(P < 0.001),FSH from 0.84 (0.30,1.50) U/L to 7.12 (4.53,10.09) U/L (P < 0.001);serum testosterone level from 0 (0,0.45) nmol/L to 2.46 (0.56,11.45) nmol/L (P =0.004) and testicular volume from 2.0 (2.0,4.0) ml to 4.0 (3.0,6.0) ml (P =0.005).Sperm was detected in seminal samples after treatment for 8 weeks in two patients and for 12 weeks in one patients.Three out of 14 patients showed poor response to pulsatile GnRH therapy.Conclusion Pulsatile GnRH therapy can effectively establish the pituitarytesticular axis function for most patients with pituitary stalk interruption syndrome,indicating enough reserve of gonadotrophs in the pituitary.%目的 评价促性腺激素释放激素(GnRH)脉冲治疗对男性垂体柄中断综合征(PSIS)患者垂体-睾丸轴功能的影响.方法 回顾性分析北京协和医院内分泌科2014年4月至2015年9月14例男性PSIS患者,应用GnRH皮下脉冲输注治

  20. Pulsatile flow and simple flow control method during weaning period in centrifugal pump: toward more expanded usage in open heart surgery.

    Science.gov (United States)

    Nishida, H; Koyanagi, H; Endo, M; Suzuki, S; Oshiyama, H; Nojiri, C; Fukasawa, H; Akutsu, T

    1994-09-01

    To expand the usage of the centrifugal pump (CP) in open heart surgery, we performed two studies. In the first, we evaluated pulsatile flow in the CP. In vitro pump performance of the Terumo Capiox pump (TCP) and the Sarns Delphin pump (SDP) and increase of free hemoglobin (mg/dl) after driving 6 h were investigated using bovine blood. A roller pump (RP) was used as a comparison. Equally effective pulsatile flow was obtained in both CPs. Hemolysis was less severe in TCP (120 mg/dl) than SDP (210 mg/dl) and RP (320 mg/dl). In the second study, we evaluated a simple flow control method. Flow rate was easily controlled with step-wise clamping of 3-pronged tubing (Triple-flow) without changing rotational speed, regardless of afterload. Fluctuation of flow was much less with this method than with the rotational speed change method. The use of pulsatile flow of TCP, with its minimum increase of hemolysis and the easier flow control method during the weaning process, may expand the usage of CP in open heart surgery.

  1. Genetics Home Reference: isolated growth hormone deficiency

    Science.gov (United States)

    ... deficiency dwarfism, pituitary growth hormone deficiency dwarfism isolated GH deficiency isolated HGH deficiency isolated human growth hormone deficiency isolated somatotropin deficiency isolated somatotropin deficiency disorder ...

  2. Hormonal contraception and platelet function.

    Science.gov (United States)

    Saleh, A A; Ginsburg, K A; Duchon, T A; Dorey, L G; Hirata, J; Alshameeri, R S; Dombrowski, M P; Mammen, E F

    1995-05-15

    73 healthy women (29 controls, 25 using OCs, and 19 using Norplant) were selected from the clinic population at North Oakland Medical Center for inclusion in this study after obtaining informed consent. Age, race, height, weight, blood pressure, and cigarette smoking were recorded for each subject. 12 patients were on monophasic OCs while 13 were on triphasic preparations. Both hormonal contraceptive groups had used their particular contraceptive for at least 3 months prior to blood drawing. Platelet tests were performed within 2 hours of sample collection: platelet counts (PLC) and mean platelet volume (MPV) were determined on an Automated Platelet Counter (Baker 810 Platelet Analyzer). Whole blood aggregation was performed on a platelet aggregometer (Chrono-Log, Model 550) using both ADP (ADP, 5 mM) and collagen (COLL, 2 mcg/ml) as inducing agents. Demographic differences were not significant (p 0.05) among the 3 treatment groups, whose average age was 25.3-25.8 years old. Furthermore, no significant differences (p 0.05) in platelet function were detected among controls or subjects receiving either oral contraceptives or Norplant, compared to control patients. The mean platelet counts (X 10/9/L) were 223 for OC users, 231 for Norplant users, and 232 for controls. The respective platelet aggregation (ADP, ohms) values were 12.5, 18.0, and 19.2 as well as (COLL, ohms) 35.6, 40.7, and 39.0. These results demonstrated that there is no evidence for altered platelet function, with the testing methods employed, in women using either Norplant or combination low dose oral contraceptives. To date, several studies have examined this issue, with contradictory reports about the effects of hormonal contraceptives in platelet function. After controlling for differences between various steroid preparations and other such confounding variables, some of these conflicting conclusions could be the result of a lack of uniformity among the methods used to evaluate platelet aggregation

  3. Genotoxic potential of nonsteroidal hormones

    Directory of Open Access Journals (Sweden)

    Topalović Dijana

    2015-01-01

    Full Text Available Hormones are cellular products involved in the regulation of a large number of processes in living systems, and which by their actions affect the growth, function and metabolism of cells. Considering that hormones are compounds normally present in the organism, it is important to determine if they can, under certain circumstances, lead to genetic changes in the hereditary material. Numerous experimental studies in vitro and in vivo in different systems, from bacteria to mammals, dealt with the mutagenic and genotoxic effects of hormones. This work presents an overview of the research on genotoxic effects of non­steroidal hormones, although possible changes of genetic material under their influence have not still been known enough, and moreover, investigations on their genotoxic influence have given conflicting results. The study results show that mechanisms of genotoxic effect of nonsteroidal hormones are manifested through the increase of oxidative stress by arising reactive oxygen species. A common mechanism of ROS occurence in thyroid hormones and catecholamines is through metabolic oxidation of their phenolic groups. Manifestation of insulin genotoxic effect is based on production of ROS by activation of NADPH isophorms, while testing oxytocin showed absence of genotoxic effect. Considering that the investigations on genotoxicity of nonsteroidal hormones demonstrated both positive and negative results, the explanation of this discordance involve limitations of test systems themselves, different cell types or biological species used in the experiments, different level of reactivity in vitro and in vivo, as well as possible variations in a tissue-specific expression. Integrated, the provided data contribute to better understanding of genotoxic effect of nonsteroidal hormones and point out to the role and mode of action of these hormones in the process of occurring of effects caused by oxidative stress. [Projekat Ministarstva nauke Republike

  4. [Hormonal therapy of advanced or relapsed ovarian granulosa cell tumor].

    Science.gov (United States)

    Sun, H; Bai, P

    2016-07-01

    Ovarian granulosa cell tumor is a rare gynecologic malignancy with hormonal activity. Surgical excision is the standard treatment for this disease. Most patients present excellent short term prognosis, however, late relapse often occurs, even after many years. Viable treatments of advanced or relapsed granulosa cell tumor are still limited, and the optimal therapy method has not been established. Compared with chemotherapy and radiotherapy, hormonal therapy is a well-tolerated treatment which can be administrated over a long period of time without serious side effects, and the combined application of hormones may achieve a better outcome. Therefore, hormonal therapy has been suggested as a potential treatment option for patients with advanced or relapsed granulosa cell tumor, and to extend the tumor-free interval and attenuate the disease progression. Future researches should be focused on the identification of the hormonal therapy which may provide the greatest clinical benefit, comparing and analyzing the effects of different combined therapeutic regimens of hormone drugs, and on the synthesis of drugs highly activating estrogen receptor β expressed in the granulosa cell tumor cells. PMID:27531259

  5. Discrimination ability and reproducibility of a new index reflecting autonomic nervous function based on pulsatile amplitude of photoplethysmography.

    Science.gov (United States)

    Kano, Yusuke; Yoshizawa, Makoto; Sugita, Norihiro; Abe, Makoto; Homma, Noriyasu; Tanaka, Akira; Yamauchi, Tsuyoshi; Miura, Hidekazu; Shiraishi, Yasuyuki; Yambe, Tomoyuki

    2014-01-01

    A new physiological index (μ(PA)) is proposed to represent the autonomic nervous system (ANS) function. The index μ(PA) is defined as the natural logarithm of the ratio between two different frequency components of the pulsatile amplitude of the photoplethysmogram (PPG) signal. The discrimination ability and the reproducibility of μ(PA) have been compared with other traditional ANS indices. In the experiment, the electrocardiogram, the PPG and continuous blood pressure were measured in 59 healthy young subjects (age 25.7 ± 6.3) and 86 healthy elderly subjects (age 70.2 ± 4.1) at rest. The discrimination ability and the reproducibility were evaluated by Cohen's d between young and elderly groups and by the interclass correlation coefficient, respectively. The results showed that the elderly subjects were significantly (p<;0.001) lower than young subjects in μ(PA) and a few traditional indices introduced to be compared with μ(PA). Therefore, it suggests that μ(PA) is associated with the decrease in the ANS function accompanied by aging. Moreover, it showed that the discrimination ability and the reproducibility of the proposed index are comparable or larger than those of traditional indices. The proposed index based on the PPG signal will be applied to tele-healthcare systems for monitoring people's health in daily life in combination with the ratio of the standard deviation of the R-R intervals to their average value (CVRR). PMID:25570325

  6. Sensitivity Analysis of Pulsatile Hydromagnetic Biofluid Flow and Heat Transfer with Non Linear Darcy-Forchheimer Drag

    Directory of Open Access Journals (Sweden)

    S. Rawat

    2016-01-01

    Full Text Available In the present paper we examine the pulsatile hydromagnetic flow and heat transfer of a non-Newtonian biofluid through a saturated non-Darcian porous medium channel. The upper plate of the channel is heated and the lower plate is cooled. The Nakamura-Sawada rheological model is employed which provides a higher yield stress than the Casson model. A Darcy-Forchheimer porous medium drag force model is incorporated to simulate blood vessel blockage with deposits in the cardiovascular system. Viscous heating is also included in the energy equation. The governing conservation equations for mass, momentum and energy equation are transformed into a system of nonlinear, coupled ordinary differential equations and these are solved numerically using finite element method. The effect of other important parameters such as magnetohydrodynamic parameter (Nm, Reynolds number (Re, Eckert number (Ec, Darcian parameter (, Forchheimer parameter (NF and Prandtl number on velocity and temperature profiles are studied graphically. Spatial-temporal velocity and temperature profile visualizations are also presented. Numerical results shows that normalized fluid velocity (U increases throughout the channel (-1 < Y < 1 with an increase in Reynolds number, Darcian parameter, steady pressure gradient parameter and rheological parameter; conversely velocity is decreased with the increase in magnetic parameter and Forchheimer quadratic drag parameter. Higher Eckert number (Ec = 3 is also found to have a considerable effect on temperature ( profile. Finite difference numerical computations are also compared with the finite element solutions to verify efficiency and accuracy.

  7. Pulsatile magneto-hydrodynamic blood flows through porous blood vessels using a third grade non-Newtonian fluids model.

    Science.gov (United States)

    Akbarzadeh, Pooria

    2016-04-01

    In this paper, the unsteady pulsatile magneto-hydrodynamic blood flows through porous arteries concerning the influence of externally imposed periodic body acceleration and a periodic pressure gradient are numerically simulated. Blood is taken into account as the third-grade non-Newtonian fluid. Besides the numerical solution, for small Womersley parameter (such as blood flow through arterioles and capillaries), the analytical perturbation method is used to solve the nonlinear governing equations. Consequently, analytical expressions for the velocity profile, wall shear stress, and blood flow rate are obtained. Excellent agreement between the analytical and numerical predictions is evident. Also, the effects of body acceleration, magnetic field, third-grade non-Newtonian parameter, pressure gradient, and porosity on the flow behaviors are examined. Some important conclusions are that, when the Womersley parameter is low, viscous forces tend to dominate the flow, velocity profiles are parabolic in shape, and the center-line velocity oscillates in phase with the driving pressure gradient. In addition, by increasing the pressure gradient, the mean value of the velocity profile increases and the amplitude of the velocity remains constant. Also, when non-Newtonian effect increases, the amplitude of the velocity profile. PMID:26792174

  8. Gastroretentive Pulsatile Release Tablets of Lercanidipine HCl: Development, Statistical Optimization, and In Vitro and In Vivo Evaluation

    Directory of Open Access Journals (Sweden)

    Gagganapalli Santhoshi Reddy

    2014-01-01

    Full Text Available The present study was aimed at the development of gastroretentive floating pulsatile release tablets (FPRTs of lercanidipine HCl to enhance the bioavailability and treat early morning surge in blood pressure. Immediate release core tablets containing lercanidipine HCl were prepared and optimized core tablets were compression-coated using buoyant layer containing polyethylene oxide (PEO WSR coagulant, sodium bicarbonate, and directly compressible lactose. FPRTs were evaluated for various in vitro physicochemical parameters, drug-excipient compatibility, buoyancy, swelling, and release studies. The optimized FPRTs were tested in vivo in New Zealand white rabbits for buoyancy and pharmacokinetics. DoE optimization of data revealed FPRTs containing PEO (20% w/w with coat weight 480 mg were promising systems exhibiting good floating behavior and lag time in drug release. Abdominal X-ray imaging of rabbits after oral administration of the tablets, confirmed the floating behavior and lag time. A quadratic model was suggested for release at 7th and 12th h and a linear model was suggested for release lag time. The FPRT formulation improved pharmacokinetic parameters compared to immediate release tablet formulation in terms of extent of absorption in rabbits. As the formulation showed delay in drug release both in vitro and in vivo, nighttime administration could be beneficial to reduce the cardiovascular complications due to early morning surge in blood pressure.

  9. 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.

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

    Science.gov (United States)

    Verma, Vivek; Balasubramanian, K

    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 7-10mm 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 9h, lag time of 3h 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(-9) m(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. PMID:24907763

  11. Comparison of the standard roller pump and a pulsatile centrifugal pump for extracorporeal circulation during routine coronary artery bypass grafting.

    Science.gov (United States)

    Driessen, J J; Fransen, G; Rondelez, L; Schelstraete, E; Gevaert, L

    1991-01-01

    The present prospective study compared the standard nonpulsatile twin roller pump with the Sarns centrifugal pump, in the pulsatile mode, as arterial pumps for extracorporeal circulation during coronary artery bypass grafting (CABG). The study was conducted in two consecutive groups of 25 patients receiving a standard anaesthetic and surgical protocol. The investigated parameters included haemodynamic profiles, oxygen exchange, blood gas and acid-base homeostasis, haematology, coagulation and complement consumption. With comparable settings for pump flow, gas flow and delivered oxygen concentrations, there was no difference between the groups in the main haemodynamic parameters during cardiopulmonary bypass (CPB). However, a tenfold lower dose of sodium nitroprusside was required to keep systemic vascular resistance within physiologic limits during CPB in the centrifugal group (C group) compared with the roller group (R group). During rewarming oxygen extraction was higher in the C group than in the R group. During the first eight hours after CPB no differences in haemodynamics, oxygenation parameters and pulmonary shunt between the groups were observed. During, as well as after, CPB there was no significant difference in blood gas and acid-base homeostasis between either group. Average postoperative blood loss via chest tubes, total transfusions of blood products, haemoglobin and coagulation did not differ between the two groups. However, the white blood cell count, corrected for changes in haematocrit, decreased during the early phase of CPB in the R group, but not in the C group.(ABSTRACT TRUNCATED AT 250 WORDS)

  12. Fluid Dynamic Characterization of a Polymeric Heart Valve Prototype (Poli-Valve) tested under Continuous and Pulsatile Flow Conditions

    Science.gov (United States)

    De Gaetano, Francesco; Serrani, Marta; Bagnoli, Paola; Brubert, Jacob; Stasiak, Joanna; Moggridge, Geoff D.; Costantino, Maria Laura

    2016-01-01

    Introduction Only mechanical and biological heart valve prostheses are currently commercially available. The former show longer durability but require anticoagulant therapy, the latter display better fluid dynamic behaviour but do not have adequate durability. New Polymeric Heart Valves (PHVs) could potentially combine the haemodynamic properties of biological valves with the durability of mechanical valves. This work presents a hydrodynamic evaluation of two groups of newly developed supra-annular tri-leaflet prosthetic heart valves made from styrenic block copolymers (SBC): Poli-Valves. Methods Two types of Poli-Valves made of SBC differing in polystyrene fraction content were tested under continuous and pulsatile flow conditions as prescribed by ISO 5840 Standard. An ad - hoc designed pulse duplicator allowed the valve prototypes to be tested at different flow rates and frequencies. Pressure and flow were recorded; pressure drops, effective orifice area (EOA), and regurgitant volume were computed to assess the valve’s behaviour. Results Both types Poli-Valves met the minimum requirements in terms of regurgitation and EOA as specified by ISO 5840 Standard. Results were compared with five mechanical heart valves (MHVs) and five tissue heart valves (THVs), currently available on the market. Conclusion Based on these results, polymeric heart valves based on styrenic block copolymers, as Poli-Valves are, can be considered as promising alternative for heart valve replacement in near future. PMID:26689146

  13. Placental Transfer of Perfluoroalkyl Substances and Associations with Thyroid Hormones: Beijing Prenatal Exposure Study

    Science.gov (United States)

    Yang, Lin; Li, Jingguang; Lai, Jianqiang; Luan, Hemi; Cai, Zongwei; Wang, Yibaina; Zhao, Yunfeng; Wu, Yongning

    2016-02-01

    Perfluoroalkyl substances (PFASs) have been detected in wildlife and human samples worldwide. Toxicology research showed that PFASs could interfere with thyroid hormone homeostasis. In this study, eight PFASs, fifteen PFAS precursors and five thyroid hormones were analyzed in 157 paired maternal and cord serum samples collected in Beijing around delivery. Seven PFASs and two precursors were detected in both maternal and cord sera with significant maternal-fetal correlations (r = 0.336 to 0.806, all P hormone (TSH) was negatively correlated with most maternal PFASs (r = -0.261 to -0.170, all P hormone homeostasis in humans.

  14. Specific involvement of gonadal hormones in the functional maturation of growth hormone releasing hormone (GHRH) neurons.

    Science.gov (United States)

    Gouty-Colomer, Laurie-Anne; Méry, Pierre-François; Storme, Emilie; Gavois, Elodie; Robinson, Iain C; Guérineau, Nathalie C; Mollard, Patrice; Desarménien, Michel G

    2010-12-01

    Growth hormone (GH) is the key hormone involved in the regulation of growth and metabolism, two functions that are highly modulated during infancy. GH secretion, controlled mainly by GH releasing hormone (GHRH), has a characteristic pattern during postnatal development that results in peaks of blood concentration at birth and puberty. A detailed knowledge of the electrophysiology of the GHRH neurons is necessary to understand the mechanisms regulating postnatal GH secretion. Here, we describe the unique postnatal development of the electrophysiological properties of GHRH neurons and their regulation by gonadal hormones. Using GHRH-eGFP mice, we demonstrate that already at birth, GHRH neurons receive numerous synaptic inputs and fire large and fast action potentials (APs), consistent with effective GH secretion. Concomitant with the GH secretion peak occurring at puberty, these neurons display modifications of synaptic input properties, decrease in AP duration, and increase in a transient voltage-dependant potassium current. Furthermore, the modulation of both the AP duration and voltage-dependent potassium current are specifically controlled by gonadal hormones because gonadectomy prevented the maturation of these active properties and hormonal treatment restored it. Thus, GHRH neurons undergo specific developmental modulations of their electrical properties over the first six postnatal weeks, in accordance with hormonal demand. Our results highlight the importance of the interaction between the somatotrope and gonadotrope axes during the establishment of adapted neuroendocrine functions.

  15. Revisiting Thyroid Hormones in Schizophrenia

    Directory of Open Access Journals (Sweden)

    Nadine Correia Santos

    2012-01-01

    Full Text Available Thyroid hormones are crucial during development and in the adult brain. Of interest, fluctuations in the levels of thyroid hormones at various times during development and throughout life can impact on psychiatric disease manifestation and response to treatment. Here we review research on thyroid function assessment in schizophrenia, relating interrelations between the pituitary-thyroid axis and major neurosignaling systems involved in schizophrenia’s pathophysiology. These include the serotonergic, dopaminergic, glutamatergic, and GABAergic networks, as well as myelination and inflammatory processes. The available evidence supports that thyroid hormones deregulation is a common feature in schizophrenia and that the implications of thyroid hormones homeostasis in the fine-tuning of crucial brain networks warrants further research.

  16. Sex Hormones and Immune Dimorphism

    Science.gov (United States)

    Bhatia, Aruna; Sekhon, Harmandeep Kaur; Kaur, Gurpreet

    2014-01-01

    The functioning of the immune system of the body is regulated by many factors. The abnormal regulation of the immune system may result in some pathological conditions. Sex hormones of reproductive system are one of the major factors that regulate immune system due to the presence of hormone receptors on immune cells. The interaction of sex hormones and immune cells through the receptors on these cells effect the release of cytokines which determines the proliferation, differentiation, and maturation of different types of immunocytes and as a result the outcome of inflammatory or autoimmune diseases. The different regulations of sex hormones in both sexes result in immune dimorphism. In this review article the mechanism of regulation of immune system in different sexes and its impact are discussed. PMID:25478584

  17. Sex Hormones and Immune Dimorphism

    Directory of Open Access Journals (Sweden)

    Aruna Bhatia

    2014-01-01

    Full Text Available The functioning of the immune system of the body is regulated by many factors. The abnormal regulation of the immune system may result in some pathological conditions. Sex hormones of reproductive system are one of the major factors that regulate immune system due to the presence of hormone receptors on immune cells. The interaction of sex hormones and immune cells through the receptors on these cells effect the release of cytokines which determines the proliferation, differentiation, and maturation of different types of immunocytes and as a result the outcome of inflammatory or autoimmune diseases. The different regulations of sex hormones in both sexes result in immune dimorphism. In this review article the mechanism of regulation of immune system in different sexes and its impact are discussed.

  18. Hormone Therapy for Prostate Cancer

    Science.gov (United States)

    ... agonists , which are sometimes called LHRH analogs, are synthetic proteins that are structurally similar to LHRH and ... gland to stop producing luteinizing hormone, which prevents testosterone from being produced. Treatment with an LHRH agonist ...

  19. Discrepancies between Antimullerian Hormone and Follicle Stimulating Hormone in Assisted Reproduction

    Directory of Open Access Journals (Sweden)

    Munawar Hussain

    2013-01-01

    Full Text Available Data from 107 women undergoing their first IVF/ICSI were analyzed. Relationships between antimullerian hormone (AMH and follicle stimulating hormone (FSH were analyzed after dividing patients into four groups according to AMH/FSH levels. Concordance was noted in 57% of women (both AMH/FSH either normal or abnormal while 43%of women had discordant values (AMH/FSH one hormone normal and the other abnormal. Group 1 (AMH and FSH in normal range and group 2 (normal AMH and high FSH were younger compared to group 3 (low AMH and normal FSH and group 4 (both AMH/FSH abnormal. Group 1 showing the best oocyte yield was compared to the remaining three groups. Groups 3 and 4 required higher dose of gonadotrophins for controlled ovarian hyperstimulation showing their low ovarian reserve. There was no difference in cycle cancellation, clinical pregnancy, and live birth/ongoing pregnancy rate in all groups. These tests are useful to predict ovarian response but whether AMH is a substantially better predictor is not yet established.

  20. Semen quality and reproductive hormones before orchiectomy in men with testicular cancer

    DEFF Research Database (Denmark)

    Petersen, P M; Skakkebaek, N E; Vistisen, K;

    1999-01-01

    cancer (TGCC) investigated before orchiectomy, semen analysis was carried out in 63 patients and hormonal investigations, including measurement of follicle-stimulating hormone, luteinizing hormone (LH), testosterone, estradiol, sex hormone-binding globulin (SHBG), inhibin B, and human chorionic...... gonadotropin (hCG), in 71 patients. Hormone levels in patients with elevated hCG (n = 41) were analyzed separately. To discriminate between general cancer effects and specific effects associated with TGCC, the same analyses were carried out in a group of 45 consecutive male patients with malignant lymphoma...... (group 2). Group 3 comprised 141 men employed in a Danish company who served as controls in the comparison of semen parameters. As a control group in hormone investigations, 193 men were selected randomly from the Danish National Personal Register to make up group 4. RESULTS: We found significantly lower...

  1. The Language of Journalism in Treatments of Hormone Replacement News

    Science.gov (United States)

    MacDonald, Susan Peck

    2005-01-01

    Researchers studying science communication have criticized the sensationalism that often appears in journalistic accounts of science news. This article looks at the linguistic sources of that sensationalism by analyzing the journalistic coverage of the Women's Health Initiative (WHI) study of hormone replacement research, which was abruptly…

  2. Stress hormones and physical activity

    OpenAIRE

    Editorial Office

    1991-01-01

    Hormone secretion during physical activity of specific duration and intensity is part of the stress response. In a study to investigate the secretion of ß-endorphin, leucine enkephalin and other recognised stress hormones during physical exercise, blood samples were taken from fourteen (14) healthy, male athletes who competed in a 21 km roadrace. Blood samples were collected before and after completion of the race. This study shows that ß-endorphin/ß-lipotropin, leucine enkephalin, prolact...

  3. Fatigue and cognition - hormonal perspectives

    OpenAIRE

    Möller, Marika

    2013-01-01

    Fatigue is a common complaint and considered a very challenging symptom to cope with in many different medical diseases. The assessment of fatigue is bound up with the problems of both conceptualization and definition. In addition, few studies have investigated suitable neuropsychological tests to examine fatigue and its consequences. This thesis evaluates whether neuropsychological tests can elicit cognitive fatigue. It also investigates whether specific hormones and hormon...

  4. Does growth hormone cause cancer?

    OpenAIRE

    Jenkins, P.J.; Mukherjee, A.; Shalet, S. M.

    2006-01-01

    KEYWORDS - CLASSIFICATION: adverse effects;Acromegaly;Adult;Animals;cancer epidemiology;complications;Child;Child Development;Colorectal Neoplasms;deficiency;epidemiology;etiology;Evaluation;Growth Hormone;Human Growth Hormone;Humans;Insulin-Like Growth Factor I;mechanisms of carcinogenesis;Neoplasm Recurrence,Local;Neoplasms;Neoplasms,Multiple Primary;physiology;physiopathology;Risk Factors;secretion;therapy. The ability of GH, via its mediator peptide IGF-1, to influence regulation of ce...

  5. Revisiting Thyroid Hormones in Schizophrenia

    OpenAIRE

    Nadine Correia Santos; Patrício Costa; Dina Ruano; António Macedo; Maria João Soares; José Valente; Ana Telma Pereira; Maria Helena Azevedo; Joana Almeida Palha

    2012-01-01

    Thyroid hormones are crucial during development and in the adult brain. Of interest, fluctuations in the levels of thyroid hormones at various times during development and throughout life can impact on psychiatric disease manifestation and response to treatment. Here we review research on thyroid function assessment in schizophrenia, relating interrelations between the pituitary-thyroid axis and major neurosignaling systems involved in schizophrenia’s pathophysiology. These include the ser...

  6. Plant hormone receptors: new perceptions

    OpenAIRE

    Spartz, Angela K.; William M Gray

    2008-01-01

    Plant growth and development require the integration of a variety of environmental and endogenous signals that, together with the intrinsic genetic program, determine plant form. Central to this process are several growth regulators known as plant hormones or phytohormones. Despite decades of study, only recently have receptors for several of these hormones been identified, revealing novel mechanisms for perceiving chemical signals and providing plant biologists with a much clearer picture of...

  7. History of growth hormone therapy

    OpenAIRE

    Vageesh S Ayyar

    2011-01-01

    Although the importance of the pituitary gland for growth was recognized in late 19 th century, Growth hormone (GH) therapy was made available for severely GH-deficient children and adolescents only in late 1950s. Use of GH for other conditions was limited because of the limited supply of human pituitary-derived hormone. With unlimited availability of recombinant human GH (rhGH), the scenario of GH treatment has been changed enormously. Currently there is ever increasing list of indications o...

  8. Short Stature and Growth Hormone Deficiency

    OpenAIRE

    Matemi, Sezer

    1994-01-01

    This paper summarizes the importance of measurements of height and weight in normal children and emphasizes the role of growth increments for the diagnosis of short stature Causes of short stature methods for diagnosis of GH hormone deficiency actions of growth hormone treatment of growth hormone deficiency and doses for biosynthetic GH treatment are described Key words: Short Stature Growth Hormone

  9. Hormone therapy and ovarian borderline tumors

    DEFF Research Database (Denmark)

    Mørch, Lina Steinrud; Løkkegaard, Ellen; Andreasen, Anne Helms;

    2012-01-01

    Little is known about the influence of postmenopausal hormone therapy on the risk of ovarian borderline tumors. We aimed at assessing the influence of different hormone therapies on this risk.......Little is known about the influence of postmenopausal hormone therapy on the risk of ovarian borderline tumors. We aimed at assessing the influence of different hormone therapies on this risk....

  10. Growth Hormone and Endocrinopathies

    International Nuclear Information System (INIS)

    This is an analysis of 39 patients studied at the Yonsei Medical Center from January, 1976 to March 1979. Of these 35 patient were suspected of having hypothalamic insufficiency and subjected to the L-Dopa stimulation test to observe growth hormone secretary function while four acromegaly patient received the glucose loading test and L-Dopa stimulation test. The results are as follows: 1) The basal level of GH in the various disease was as follows: a) The basal level was lower than the control level but was not statistically significant b) In diabetes the mean value tended to higher than the control level but was not significant statistically c) In all four acromegaly patients the GH level was significantly higher than the control level 2) Of 13 patients with diabetes, nine had diabetic retinopathy, and of those nine, six showed increased L-Dopa response. However, of the four non retinopathic DM patients, only one showed increased response to L-Dopa. 3) Two patients out of ten with Sheehan's syndrome responded to L-Dopa stimulation. 4) One Patient of eight with pituitary chromophobe adenoma responded to L-Dopa stimulation. 5) Four acromegaly patients revealed 3 acidophilic adenoma and one chromophobe adenoma histologically. Of patients receiving the L-Dopa stimulation test. Two showed a paradoxical response. Two patients who received the glucose loading test showed suppressed response. 6) Of two craniopharyngioma patients, one showed increased GH response after L-Dopa stimulation. Increased response of GH after L-Dopa stimulation was seen in one two craniopharyngioma patients and also in one of two patients with short structure.

  11. Percentage of peak-to-peak pulsatility of portal blood flow can predict right-sided congestive heart failure

    Institute of Scientific and Technical Information of China (English)

    Jui-Ting Hu; Sien-Sing Yang; Yun-Chih Lai; Cheng-Yen Shih; Cheng-Wen Chang

    2003-01-01

    AIM: To study the change of portal blood flow for the prediction of the status of right-sided heart failure by using non-invasive way.METHODS: We studied 20 patients with rheumatic and atherosclerotic heart diseases. All the patients had constant systemic blood pressure and body weight 1 week prior to the study. Cardiac index (CI), left ventricular end-diastolic pressure (LVEDP), mean aortic pressure (AOP), pulmonary wedge pressure (PWP), mean pulmonary arterial pressure (PAP), mean right atrial pressure (RAP), right ventricular end-diastolic pressure (RVEDP) were recorded during cardiac catheterization. Ten patients with RAP<10 mmHg were classified as Group 1. The remaining 10 patients with RAP ≥ 10 mmHg were classified as Group 2. Portal blood velocity profiles were studied using an ultrasonic Doppler within 12h after cardiac catheterization.RESULTS: CI, AOP, and LVEDP had no difference between two groups. Patients in Group 1 had normal PWP (14.6±7.3mmHg), PAP (25.0±8.2 mmHg), RAP (4.7±2.4 mmHg), and RVEDP (6.4±2.7 mmHg). Patients in Group 2 had increased PWP (29.9±9.3 mmHg), PAP (46.3±13.2 mmHg), RAP (17.5±5.7 mmHg), and RVEDP (18.3±5.6 mmHg) (P<0.001).Mean values of maximum portal blood velocity (Vmax), mean portal blood velocity (Vmean), cross-sectional area (Area)and portal blood flow volume (PBF) had no difference between 2 groups. All the patients in Group 1 had a continuous antegrade portal flow with a mean percentage of peak-topeak pulsatility (PP) 27.0±8.9 % (range: 17-40 %). All the patients in Group 2 had pulsatile portal flow with a mean PP 86.6±45.6 (range: 43-194 %). One patient had a transient stagnant and three patients had a transient hepatofugal portal flow, which occurred mainly during the ventricular systole. Vmax, Vmean and PBF had a positive correlation with CO (P<0.001) but not with AOP, LVEDP, PWP, PAP,RAP, and RVEDP.PP showed a good correlation (P<0.001)with PWP, PAP, RAP, and RVEDP but not with CI, AOP, and LVEDP. All

  12. Thyroid Hormone Deiodinases and Cancer

    Directory of Open Access Journals (Sweden)

    Antonio eBianco

    2012-06-01

    Full Text Available Deiodinases constitute a group of thioredoxin-containing selenoenzymes that play an important function in thyroid hormone homeostasis and control of thyroid hormone action. There are three known deiodinases: D1 and D2 activate the pro-hormone thyroxine (T4 to T3, the most active form of thyroid hormone, while D3 inactivates thyroid hormone and terminates T3 action. A number of studies indicate that deiodinase expression is altered in several types of cancers, suggesting that (i they may represent a useful cancer marker and/or (ii could play a role in modulating cell proliferation - in different settings thyroid hormone modulates cell proliferation. For example, although D2 is minimally expressed in human and rodent skeletal muscle, its expression level in rhabdomyosarcoma (RMS-13 cells is 3-4 fold higher. In basal cell carcinoma (BCC cells, sonic hedgehog (Shh-induced cell proliferation is accompanied by induction of D3 and inactivation of D2. Interestingly a 5-fold reduction in the growth of BCC in nude mice was observed if D3 expression was knocked down. A decrease in D1 activity has been described in renal clear cell carcinoma, primary liver cancer, lung cancer, and some pituitary tumors, while in breast cancer cells and tissue there is an increase in D1 activity. Furthermore D1 mRNA and activity were found to be decreased in papillary thyroid cancer while D1 and D2 activities were significantly higher in follicular thyroid cancer tissue, in follicular adenoma and in anaplastic thyroid cancer. It is conceivable that understanding how deiodinase dysregulation in tumor cells affect thyroid hormone signaling and possibly interfere with tumor progression could lead to new antineoplastic approaches.

  13. Alternatives of menopausal hormone therapy

    Directory of Open Access Journals (Sweden)

    Kutlešić Ranko M.

    2016-01-01

    Full Text Available Introduction. It has been generally accepted that the benefits of menopausal hormone therapy outweigh the risks, but there are still some concerns about the administration of menopausal hormone therapy, which has introduced alternative treatments. Pharmacological Alternatives. Central alpha-2 agonist clonidine is only marginally more effective than placebo, and significantly less effective than estrogen. Antiepileptic drug gabapentin reduces hot flashes; however, it is less effective than estrogen. Selective serotonin reuptake inhibitors (paroxetine and fluoxetine and selective noradrenaline reuptake inhibitors (venlafaxine reduce vasomotor symptoms and improve depression, anxiety and sleep. Results of studies about dehydroepiandrosterone effects on menopausal symptoms are inconsistent and additional investigations are needed. Non-Pharmacological Alternatives. Stellatum ganglion blockade is a successful treatment for reducing vasomotor symptoms in patients with contraindications for menopausal hormone therapy. Efficacy of acupuncture, homeopathy and reflexology should be proved by adequate studies. Phytoestrogens could reduce vasomotor symptoms but to a lesser extent than conventional menopausal hormone therapy. However, they have not been proved yet to provide cardiovascular protection and prevention of osteoporosis, nor they could be recommended instead of traditional menopausal hormone therapy. There is a concern about their undesirable effects. Adequate diet, unchanging body weight within ideal values and adequate physical activities have beneficial long-term effects, first of all on preservation of bone density. Alternatives for Atrophic Changes of Vaginal Epithelium. Menopausal symptoms resulting from vaginal atrophy could be resolved by use of hydrophilic preparations, lubricants and topical lidocaine cream or 4% lidocaine water solution for dyspareunia. Conclusion. If there are contrain­dications to menopausal hormone therapy or

  14. Pulsatile blood flow in human bone assessed by laser-Doppler flowmetry and the interpretation of photoplethysmographic signals

    International Nuclear Information System (INIS)

    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)

  15. Pulsatile Stress in Middle-Aged Patients With Type 1 or Type 2 Diabetes Compared With Nondiabetic Control Subjects

    Science.gov (United States)

    Philips, Jean-Christophe; Marchand, Monique; Scheen, André J.

    2010-01-01

    OBJECTIVE Arterial pulse pressure is considered to be an independent cardiovascular risk factor. We compared pulse pressure during an active orthostatic test in middle-aged patients with type 1 diabetes and with type 2 diabetes and corresponding nondiabetic control subjects. RESEARCH DESIGN AND METHODS Forty patients with type 1 diabetes (mean age 50 years, diabetes duration 23 years, and BMI 23.0 kg/m2) were compared with 40 nonhypertensive patients with type 2 diabetes (respectively, 50 years, 8 years, and 29.7 kg/m2). Patients taking antihypertensive agents or with renal insufficiency were excluded. All patients were evaluated with a continuous noninvasive arterial blood pressure monitoring (Finapres) in standing (1 min), squatting (1 min), and again standing position (1 min). Patients with type 1 or type 2 diabetes were compared with two groups of 40 age-, sex- and BMI-matched healthy subjects. RESULTS Patients with type 1 diabetes and patients with type 2 diabetes showed significantly higher pulse pressure, heart rate, and double product of pulse pressure and heart rate (PP×HR) (type 1: 5,263 vs. 4,121 mmHg/min, P = 0.0004; type 2: 5,359 vs. 4,321 mmHg, P = 0.0023) levels than corresponding control subjects. There were no significant differences between patients with type 1 diabetes and type 2 diabetes regarding pulse pressure (59 vs. 58 mmHg), heart rate (89 vs. 88/min), and PP×HR (5,263 vs. 5,359 mmHg/min). CONCLUSIONS Patients with type 1 diabetes have increased levels of peripheral PP, an indirect marker of arterial stiffness, and PP×HR, an index of pulsatile stress, comparable to those of nonhypertensive patients with type 2 diabetes at similar mean age of 50 years. PMID:20693351

  16. 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.)

  17. Presence and concentration of 17 hormones in human placenta processed for encapsulation and consumption.

    Science.gov (United States)

    Young, Sharon M; Gryder, Laura K; Zava, David; Kimball, David W; Benyshek, Daniel C

    2016-07-01

    Human maternal placentophagy is a rare but growing practice in several industrialized countries among postpartum mothers seeking a variety of purported health benefits attributed to the practice. These postpartum mothers typically consume their placenta as a processed, encapsulated supplement. To determine whether free (unconjugated) steroid hormones and melatonin in placenta can survive the encapsulation process (namely steaming and dehydration), we analyzed 28 placenta samples processed for encapsulation using liquid chromatography tandem-mass spectrometry (LC-MS/MS) to evaluate the concentration of 17 hormones. The results revealed detectable concentrations for 16 of the hormones analyzed, some in concentrations that could conceivably yield physiological effects. PMID:27324105

  18. Hormone therapy and ovarian cancer

    DEFF Research Database (Denmark)

    Mørch, Lina Steinrud; Løkkegaard, Ellen; Andreasen, Anne Helms;

    2009-01-01

    CONTEXT: Studies have suggested an increased risk of ovarian cancer among women taking postmenopausal hormone therapy. Data are sparse on the differential effects of formulations, regimens, and routes of administration. OBJECTIVE: To assess risk of ovarian cancer in perimenopausal and postmenopau......CONTEXT: Studies have suggested an increased risk of ovarian cancer among women taking postmenopausal hormone therapy. Data are sparse on the differential effects of formulations, regimens, and routes of administration. OBJECTIVE: To assess risk of ovarian cancer in perimenopausal...... and postmenopausal women receiving different hormone therapies. DESIGN AND SETTING: Nationwide prospective cohort study including all Danish women aged 50 through 79 years from 1995 through 2005 through individual linkage to Danish national registers. Redeemed prescription data from the National Register...... bands included hormone exposures as time-dependent covariates. PARTICIPANTS: A total of 909,946 women without hormone-sensitive cancer or bilateral oophorectomy. MAIN OUTCOME MEASURE: Ovarian cancer. RESULTS: In an average of 8.0 years of follow-up (7.3 million women-years), 3068 incident ovarian...

  19. Radioimmunological and clinical studies with luteinizing hormone releasing hormone (LRH)

    International Nuclear Information System (INIS)

    Radioimmunoassay for Luteinizing Hormone Releasing Hormone (LRH) has been established, tested and applied. Optimal conditions for the performance with regards to incubation time, incubation temperature, concentration of antiserum and radiolabelled LRH have been established. The specificity of the LRH immunoassay was investigated. Problems with direct measurement of LRH in plasmas of radioimmunoassay are encountered. The LRH distribution in various tissues of the rat are investigated. By means of a system for continuous monitoring of LH and FSH in women the lowest effective dose of LRH causing a significant release of LH and FSH could be established. (Auth.)

  20. The pulsatile motion of a semi-infinite bubble in a channel: flow fields, and transport of an inactive surface-associated contaminant

    Science.gov (United States)

    Zimmer, Maximillian E.; Williams, Harvey A. R.; Gaver, Donald P.

    2005-08-01

    We investigate a theoretical model of the pulsatile motion of a contaminant-doped semi-infinite bubble in a rectangular channel. We examine the fluid mechanical behaviour of the pulsatile bubble, and its influence on the transport of a surface-inactive contaminant (termed surfinactant). This investigation is used to develop a preliminary understanding of surfactant responses during unsteady pulmonary airway reopening. Reopening is modelled as the pulsatile motion of a semi-infinite gas bubble in a horizontal channel of width 2a filled with a Newtonian liquid of viscosity mu and constant surface tension gamma. A modified Langmuir sorption model is assumed, which allows for the creation and respreading of a surface multilayer. The bubble is forced via a time-dependent volume flux Q(t) with mean and oscillatory components (Q_{M} and Q_{omega }, respectively) at frequency omega . The flow behaviour is governed by the dimensionless parameters: Ca_{M} {=} mu Q_{M}/(2agamma ), a steady-state capillary number, which represents the ratio of viscous to surface tension forces; Ca_{Omega } {=} mu Q_{omega }/(2agamma ), an oscillatory forcing magnitude; Omega {=} omega mu a/gamma , a dimensionless frequency that represents the ratio of viscous relaxation to oscillatory-forcing timescales; and A {=} 2Ca_{Omega }/Omega , a dimensionless oscillation amplitude. Our simulations indicate that contaminant deposition and retention in the bubble cap region occurs at moderate frequencies if retrograde bubble motion develops during the oscillation cycle. However, if oscillations are too rapid the ensuing large forward tip velocities cause a net loss of contaminant from the bubble tip. Determination of an optimal oscillation range may be important in reducing ventilator-induced lung injury associated with infant and adult respiratory distress syndromes by increasing surfactant transport to regions of collapsed airways.

  1. 阿莫西林克拉维酸钾脉冲胶囊的制备%Preparation of Amoxicillin and Clavulanate Potassium Pulsatile Capsules

    Institute of Scientific and Technical Information of China (English)

    刘杰; 张涛; 黄华

    2011-01-01

    Amoxicillin and clavulanate potassium pellets were prepared by extrude-spheronization method.The pH-dependent pulsatile capsules were prepared by the above pellets uncoated, Eudragit(R) L30D-55 coated pellets and Eudragit S100 coated pellets with the ratio of 1 ∶ 1∶ 1. The in vitro release of pH dependent pulsatile capsules was discussed. The effects of coating level and HPMC insulation layer on in vitro released were performed. The pulsatile capsules exhibited an excellent pH dependent release profile in pH 2.0, pH 6.0 and pH 7.8 phosphate buffer solution.%采用挤出滚圆法制备阿莫西林克拉维酸钾微丸,再分别以Eudragit(R)L30D-55和Eudragit(R)S100包衣.将上述3种在不同pH条件下释放的微丸按等比例混匀后装入囊壳,得脉冲胶囊.并进行了体外释放度研究.考察了包衣增重以及pH敏感型材料包衣后添加HPMC隔离层对体外释放度的影响.结果显示,制备的脉冲胶囊在pH 2.0、6.0和7.8的磷酸盐缓冲液中,呈pH依赖型的脉冲释药.

  2. Gastrointestinal hormone research - with a Scandinavian annotation

    DEFF Research Database (Denmark)

    Rehfeld, Jens F

    2015-01-01

    as a blood-borne hormone, a neurotransmitter, a local growth factor or a fertility factor. The targets of gastrointestinal hormones are specific G-protein-coupled receptors that are expressed in the cell membranes also outside the digestive tract. Thus, gut hormones not only regulate digestive functions......Gastrointestinal hormones are peptides released from neuroendocrine cells in the digestive tract. More than 30 hormone genes are currently known to be expressed in the gut, which makes it the largest hormone-producing organ in the body. Modern biology makes it feasible to conceive the hormones...... under five headings: The structural homology groups a majority of the hormones into nine families, each of which is assumed to originate from one ancestral gene. The individual hormone gene often has multiple phenotypes due to alternative splicing, tandem organization or differentiated posttranslational...

  3. 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...... 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...

  4. Internal Jugular Vein Cross-Sectional Area and Cerebrospinal Fluid Pulsatility in the Aqueduct of Sylvius: A Comparative Study between Healthy Subjects and Multiple Sclerosis Patients.

    Directory of Open Access Journals (Sweden)

    Clive B Beggs

    Full Text Available Constricted cerebral venous outflow has been linked with increased cerebrospinal fluid (CSF pulsatility in the aqueduct of Sylvius in multiple sclerosis (MS patients and healthy individuals. This study investigates the relationship between CSF pulsatility and internal jugular vein (IJV cross-sectional area (CSA in these two groups, something previously unknown.65 relapsing-remitting MS patients (50.8% female; mean age = 43.8 years and 74 healthy controls (HCs (54.1% female; mean age = 43.9 years were investigated. CSF flow quantification was performed on cine phase-contrast MRI, while IJV-CSA was calculated using magnetic resonance venography. Statistical analysis involved correlation, and partial least squares correlation analysis (PLSCA.PLSCA revealed a significant difference (p<0.001; effect size = 1.072 between MS patients and HCs in the positive relationship between CSF pulsatility and IJV-CSA at C5-T1, something not detected at C2-C4. Controlling for age and cardiovascular risk factors, statistical trends were identified in HCs between: increased net positive CSF flow (NPF and increased IJV-CSA at C5-C6 (left: r = 0.374, p = 0.016; right: r = 0.364, p = 0.019 and C4 (left: r = 0.361, p = 0.020; and increased net negative CSF flow and increased left IJV-CSA at C5-C6 (r = -0.348, p = 0.026 and C4 (r = -0.324, p = 0.039, whereas in MS patients a trend was only identified between increased NPF and increased left IJV-CSA at C5-C6 (r = 0.351, p = 0.021. Overall, correlations were weaker in MS patients (p = 0.015.In healthy adults, increased CSF pulsatility is associated with increased IJV-CSA in the lower cervix (independent of age and cardiovascular risk factors, suggesting a biomechanical link between the two. This relationship is altered in MS patients.

  5. Resistance training & beta-hydroxy-beta-methylbutyrate supplementation on hormones

    Directory of Open Access Journals (Sweden)

    Hamid Arazi

    2015-10-01

    Full Text Available RESUMOIntroduction:In recent years, there was an increased interest on the effects of beta-hydroxy-beta-methylbutyrate (HMB supplementation on skeletal muscle due to its anti-catabolic effects.Objectives:To investigate the effect of HMB supplementation on body composition, muscular strength and anabolic-catabolic hormones after resistance training.Methods:Twenty amateur male athletes were randomly assigned to supplement and control groups in a double-blind crossover design and participated in four weeks resistance training. Before and after the test period fasting blood samples were obtained to determine anabolic (the growth hormone and testosterone and catabolic (cortisol hormones, and fat mass, lean body mass (LBM and muscular strength were measured. Dependent and independent t-tests were used to analyze data.Results:After the training period, there were no significant differen-ces between the groups with respect to fat mass, LBM and anabolic-catabolic hormones. HMB supplementation resulted in a significantly greater strength gain (p≤0.05.Conclusion:Greater increase in strength for HMB group was not accompanied by body composition and basal circulating anabolic-catabolic hormonal changes. It seems that HMB supplementation may have beneficial effects on neurological adaptations of strength gain.

  6. RELATIONSHIP BETWEEN PROLACTIN HORMONE LEVEL, MOLTING AND DUCK EGG PRODUCTION

    Directory of Open Access Journals (Sweden)

    T. Susanti

    2012-09-01

    Full Text Available The aims of this study were to obtain information on the mechanism of molting and the prolactin hormone levels affecting egg production. The study utilized AP (crossbred of Alabio ♂ with Peking ♀ and PA (crossbred of Peking ♂ and Alabio ♀ ducks with a total of 180 birds. The observed variables were the duration of cessation of egg production before and after molting, the prolactin hormone level in the period of molting, the egg production period before and after molting. The data was analyzed using ANOVA, regression and correlation. The results showed that AP crossbred had fewer molting (23.33% compared to PA (50.00%. The mechanism of molting is always preceded by cessation of egg production, molting and relaying. The prolactin hormone concentrations of AP and PA in the period before and after molting were significantly higher than in the period of molting. At the egg production period before molting, the prolactin hormone concentration of AP ducks was higher than the PA ducks. So that the egg production of AP before molting (0-16 weeks was higher than the PA. The egg production of AP was higher than PA, 256.66±6.00 vs 232.22±6.64 eggs for 48 weeks. So it can be concluded that the prolactin hormone affects the molting and egg production.

  7. Pathology of growth hormone excess.

    Science.gov (United States)

    Kovacs, K

    1988-09-01

    This paper briefly reviews the pathology of growth hormone excess. Prolonged oversecretion of growth hormone is associated with elevated serum growth hormone as well as somatomedian C levels and the clinical signs and symptoms of acromegaly or gigantism. Morphologic studies, including immunohistochemistry and electron microscopy, revealed that several distinct morphologic lesions can be present in the pituitary gland of patients with acromegaly or gigantism. Although substantial progress has been achieved during the last two decades, more work is required to correlate the morphologic features of adenoma cells with their biologic behavior. We feel that the future can be viewed with optimism and further exciting results can be expected by the interaction of pathologists, clinical endocrinologists and basic scientists. PMID:3070506

  8. Stress hormones and physical activity

    Directory of Open Access Journals (Sweden)

    Editorial Office

    1991-07-01

    Full Text Available Hormone secretion during physical activity of specific duration and intensity is part of the stress response. In a study to investigate the secretion of ß-endorphin, leucine enkephalin and other recognised stress hormones during physical exercise, blood samples were taken from fourteen (14 healthy, male athletes who competed in a 21 km roadrace. Blood samples were collected before and after completion of the race. This study shows that ß-endorphin/ß-lipotropin, leucine enkephalin, prolactin, and melatonin may be classified as stress hormones in physical activity of duration 80 to 120 minutes and intensity exceeding 75%-V0₂max. Widespread intra-individual variation in serum cortisol concentrations prevent definite conclusion. The un­expected increase in serum testosterone levels warrants further research.

  9. Menopausal Women's Access Path to Bioidentical Hormone Replacement Therapy: An Exploratory.

    Science.gov (United States)

    Moro, Doris; Young, Wendy; Stein, Richard; Isaac, Winston; Goodman, Deborah

    2010-01-01

    The objective of this exploratory qualitative study was to describe (1) the key factors affecting women's initial decision to explore the use of bioidentical hormone, (2) where women gather their information on bioidentical hormones, (3) the enablers and barriers to obtaining bioidentical hormones, and (4) how to improve the bioidentical hormone replacement therapy access path. The study was conducted in a compounding pharmacy located in a large urban area in southern Ontario, Canada. The participants included four postmenopausal women between the ages of 46 and 72 who self-identified as users of bioidentical hormone replacement therapy and with comprehensive provincial healthcare coverage. Participants were recruited at a compounding pharmacy with the use of tri-fold brochures, tear-sheets, and posters. The women participated in an audio-taped mini focus group. Discussion was guided by six open-ended questions. Verbatim quotes were analyzed using an affinity diagram. Participants identified three key factors related to their initial decision: (1) symptoms unalleviated by synthetic hormone replacement therapy, (2) side effects from synthetic hormone replacement therapy, and (3) personal preference. They obtained information and support from many sources, including: family/friends, publications, and specialists in menopausal health. Once participants had made a decision, they obtained a prescription and accessed bioidentical hormone replacement therapy at a compounding pharmacy. Knowledgeable primary care physicians and compounding pharmacists were seen as enablers. Lack of support/Information and costs were identifies as barriers. Improvements to bioidentical hormone replacement therapy access path were suggested. The results of this study suggest that there may be value in implementing strategies to further encourage family physicians and other specialists in menopausal health to discuss options regarding hormone replacement therapy with patients. For example, the

  10. Menopausal Women's Access Path to Bioidentical Hormone Replacement Therapy: An Exploratory.

    Science.gov (United States)

    Moro, Doris; Young, Wendy; Stein, Richard; Isaac, Winston; Goodman, Deborah

    2010-01-01

    The objective of this exploratory qualitative study was to describe (1) the key factors affecting women's initial decision to explore the use of bioidentical hormone, (2) where women gather their information on bioidentical hormones, (3) the enablers and barriers to obtaining bioidentical hormones, and (4) how to improve the bioidentical hormone replacement therapy access path. The study was conducted in a compounding pharmacy located in a large urban area in southern Ontario, Canada. The participants included four postmenopausal women between the ages of 46 and 72 who self-identified as users of bioidentical hormone replacement therapy and with comprehensive provincial healthcare coverage. Participants were recruited at a compounding pharmacy with the use of tri-fold brochures, tear-sheets, and posters. The women participated in an audio-taped mini focus group. Discussion was guided by six open-ended questions. Verbatim quotes were analyzed using an affinity diagram. Participants identified three key factors related to their initial decision: (1) symptoms unalleviated by synthetic hormone replacement therapy, (2) side effects from synthetic hormone replacement therapy, and (3) personal preference. They obtained information and support from many sources, including: family/friends, publications, and specialists in menopausal health. Once participants had made a decision, they obtained a prescription and accessed bioidentical hormone replacement therapy at a compounding pharmacy. Knowledgeable primary care physicians and compounding pharmacists were seen as enablers. Lack of support/Information and costs were identifies as barriers. Improvements to bioidentical hormone replacement therapy access path were suggested. The results of this study suggest that there may be value in implementing strategies to further encourage family physicians and other specialists in menopausal health to discuss options regarding hormone replacement therapy with patients. For example, the

  11. Growth Hormone and Cerebral Amyloidosis.

    Science.gov (United States)

    Benvenga, S; Guarneri, F

    2016-08-01

    Great interest has recently been focused on a paper reporting characteristic deposits of amyloid-β protein associated with Alzheimer's disease in brains of adults who died of Creutzfeldt-Jakob disease. As they had contracted such disease after treatment with prion-contaminated human growth hormone extracted from cadaver-derived pituitaries, the authors have suggested that interhuman transmission of Alzheimer's disease had occurred. Our previous research led us to find that amyloid-forming peptides share amino acid sequence homology, summarized by a motif. Here, we probed the amino acid sequence of human growth hormone for such a motif, and found that 2 segments fit the motif and are potentially amyloid-forming. This finding was confirmed by Aggrescan, another well-known software for the prediction of amyloidogenic peptides. Our results, taken together with data from the literature that are missing in the aforementioned paper and associated commentaries, minimize the contagious nature of the iatrogenically-acquired coexistence of Creutzfeldt-Jakob disease and Alzheimer's disease. In particular, the above mentioned paper misses literature data on intratumoral amyloidosis in growth hormone- and prolactin-secreting adenomas, tumors relatively frequent in adults, which are often silent. It cannot be excluded that some pituitaries used to extract growth hormone contained clinically silent microadenomas, a fraction of which containing amyloid deposits, and patients might had received a fraction of growth hormone (with or without prolactin) that already was an amyloid seed. The intrinsic amyloidogenicity of growth hormone, in the presence of contaminating prion protein (and perhaps prolactin as well) and amyloid-β contained in some cadavers' pituitaries, may have led to the observed co-occurring of Creutzfeldt-Jakob disease and Alzheimer's disease. PMID:27214308

  12. Hormonal interaction in diabetic pregnancy

    International Nuclear Information System (INIS)

    Serum glucose, human placental lactogen (HPL), prolactin (PRL), estradiol (E2), progesterone (P), cortisol and human growth hormone (HGH) were determined in nondiabetic (19 cases) and diabetic (19 cases) pregnant women during the 32nd and 36th week of gestation. Significant elevation of HPL, PRL, HGH and cortisol was found in the diabetic pregnant women during the 32nd week while E2 and P were not significantly changed from the corresponding levels in the nondiabetic group. One can conclude that the changes in the hormonal pattern during gestation may induce carbohydrate intolerance observed in diabetic pregnancies. (author)

  13. Advances in male hormonal contraception.

    Science.gov (United States)

    Costantino, Antonietta; Gava, Giulia; Berra, Marta; Meriggiola Maria, Cristina

    2014-11-01

    Contraception is a basic human right for its role on health, quality of life and wellbeing of the woman and of the society as a whole. Since the introduction of female hormonal contraception the responsibility of family planning has always been with women. Currently there are only a few contraceptive methods available for men, but recently, men have become more interested in supporting their partners actively. Over the last few decades different trials have been performed providing important advances in the development of a safe and effective hormonal contraceptive for men. This paper summarizes some of the most recent trials. PMID:25673544

  14. Hormonal interaction in diabetic pregnancy

    Energy Technology Data Exchange (ETDEWEB)

    Hafiez, A.R.A.; Abdel-Hafez, M.A.; Osman, E.A. (Cairo Univ. (Egypt)); Ibrahim, M.S. (Al-Azhar Univ., Cairo (Egypt))

    1984-08-01

    Serum glucose, human placental lactogen (HPL), prolactin (PRL), estradiol (E/sub 2/), progesterone (P), cortisol and human growth hormone (HGH) were determined in nondiabetic (19 cases) and diabetic (19 cases) pregnant women during the 32nd and 36th week of gestation. Significant elevation of HPL, PRL, HGH and cortisol was found in the diabetic pregnant women during the 32nd week while E/sub 2/ and P were not significantly changed from the corresponding levels in the nondiabetic group. One can conclude that the changes in the hormonal pattern during gestation may induce carbohydrate intolerance observed in diabetic pregnancies.

  15. Advances in male hormonal contraception

    Directory of Open Access Journals (Sweden)

    Costantino Antonietta

    2014-01-01

    Full Text Available Contraception is a basic human right for its role on health, quality of life and wellbeing of the woman and of the society as a whole. Since the introduction of female hormonal contraception the responsibility of family planning has always been with women. Currently there are only a few contraceptive methods available for men, but recently, men have become more interested in supporting their partners actively. Over the last few decades different trials have been performed providing important advances in the development of a safe and effective hormonal contraceptive for men. This paper summarizes some of the most recent trials.

  16. Afferent neuronal control of type-I gonadotropin releasing hormone (GnRH neurons in the human

    Directory of Open Access Journals (Sweden)

    Erik eHrabovszky

    2013-09-01

    Full Text Available Understanding the regulation of the human menstrual cycle represents an important ultimate challenge of reproductive neuroendocrine research. However, direct translation of information from laboratory animal experiments to the human is often complicated by strikingly different and unique reproductive strategies and central regulatory mechanisms that can be present in even closely related animal species. In all mammals studied so far, type-I gonadotropin releasing hormone (GnRH synthesizing neurons form the final common output way from the hypothalamus in the neuroendocrine control of the adenohypophysis. Under various physiological and pathological conditions, hormonal and metabolic signals either regulate GnRH neurons directly or act on upstream neuronal circuitries to influence the pattern of pulsatile GnRH secretion into the hypophysial portal circulation. Neuronal afferents to GnRH cells convey important metabolic-, stress-, sex steroid-, lactational- and circadian signals to the reproductive axis, among other effects. This article gives an overview of the available neuroanatomical literature that described the afferent regulation of human GnRH neurons by peptidergic, monoaminergic and amino acidergic neuronal systems. Recent studies of human genetics provided evidence that central peptidergic signaling by kisspeptins and neurokinin B play particularly important roles in puberty onset and later, in the sex steroid-dependent feedback regulation of GnRH neurons. This review article places special emphasis on the topographic distribution, sexual dimorphism, aging-dependent neuroanatomical changes and plastic connectivity to GnRH neurons of the critically important human hypothalamic kisspeptin and neurokinin B systems.

  17. Control of puberty onset and fertility by gonadotropin-releasing hormone neurons.

    Science.gov (United States)

    Herbison, Allan E

    2016-08-01

    The gonadotropin-releasing hormone (GnRH) neuronal network generates pulse and surge modes of gonadotropin secretion critical for puberty and fertility. The arcuate nucleus kisspeptin neurons that innervate the projections of GnRH neurons in and around their neurosecretory zone are key components of the pulse generator in all mammals. By contrast, kisspeptin neurons located in the preoptic area project to GnRH neuron cell bodies and proximal dendrites and are involved in surge generation in female rodents (and possibly other species). The hypothalamic-pituitary-gonadal axis develops embryonically but, apart from short periods of activation immediately after birth, remains suppressed through a combination of gonadal and non-gonadal mechanisms. At puberty onset, the pulse generator reactivates, probably owing to progressive stimulatory influences on GnRH neurons from glial and neurotransmitter signalling, and the re-emergence of stimulatory arcuate kisspeptin input. In females, the development of pulsatile gonadotropin secretion enables final maturation of the surge generator that ultimately triggers the first ovulation. Representation of the GnRH neuronal network as a series of interlocking functional modules could help conceptualization of its functioning in different species. Insights into pulse and surge generation are expected to aid development of therapeutic strategies ameliorating pubertal disorders and infertility in the clinic. PMID:27199290

  18. Investigation of the effects of dynamic change in curvature and torsion on pulsatile flow in a helical tube.

    Science.gov (United States)

    Selvarasu, N K C; Tafti, Danesh K

    2012-07-01

    Cardiovascular diseases are the number one cause of death in the world, making the understanding of hemodynamics and the development of treatment options imperative. The effect of motion of the coronary artery due to the motion of the myocardium is not extensively studied. In this work, we focus our investigation on the localized hemodynamic effects of dynamic changes in curvature and torsion. It is our objective to understand and reveal the mechanism by which changes in curvature and torsion contribute towards the observed wall shear stress distribution. Such adverse hemodynamic conditions could have an effect on circumferential intimal thickening. Three-dimensional spatiotemporally resolved computational fluid dynamics (CFD) simulations of pulsatile flow with moving wall boundaries were carried out for a simplified coronary artery with physiologically relevant flow parameters. A model with stationary walls is used as the baseline control case. In order to study the effect of curvature and torsion variation on local hemodynamics, this baseline model is compared to models where the curvature, torsion, and both curvature and torsion change. The simulations provided detailed information regarding the secondary flow dynamics. The results suggest that changes in curvature and torsion cause critical changes in local hemodynamics, namely, altering the local pressure and velocity gradients and secondary flow patterns. The wall shear stress (WSS) varies by a maximum of 22% when the curvature changes, by 3% when the torsion changes, and by 26% when both the curvature and torsion change. The oscillatory shear stress (OSI) varies by a maximum of 24% when the curvature changes, by 4% when the torsion changes, and by 28% when both the curvature and torsion change. We demonstrate that these changes are attributed to the physical mechanism associating the secondary flow patterns to the production of vorticity (vorticity flux) due to the wall movement. The secondary flow patterns

  19. 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.

  20. The 'Love Hormone' May Quiet Tinnitus

    Science.gov (United States)

    ... medlineplus.gov/news/fullstory_161110.html The 'Love Hormone' May Quiet Tinnitus Small, preliminary study suggests oxytocin ... tinnitus -- may find some relief by spraying the hormone oxytocin in their nose, a small initial study ...

  1. Mortality and reduced growth hormone secretion

    DEFF Research Database (Denmark)

    Stochholm, Kirstine; Christiansen, Jens; Laursen, Torben;

    2007-01-01

    BACKGROUND: Data regarding the mortality rates of patients with growth hormone deficiency (GHD), whether or not treated with growth hormone (GH), are limited, but an increased mortality rate among hypopituitary patients compared with the general population has been documented. Cardiovascular...

  2. Investigation of suspected growth hormone deficiency

    OpenAIRE

    Milner, R. D. G.; Burns, E C

    1982-01-01

    This paper describes views of the Health Services Human Growth Hormone Committee on how a child suspected of growth hormone deficiency should be investigated in a district general hospital or in a regional growth centre.

  3. Hormone May Be Linked to Teenage Obesity

    Science.gov (United States)

    ... 159014.html Hormone May Be Linked to Teenage Obesity Researchers suspect low levels of spexin might play ... reduced levels of this hormone in adults with obesity. Overall, our findings suggest spexin may play a ...

  4. Hormone May Be Linked to Teenage Obesity

    Science.gov (United States)

    ... page: https://medlineplus.gov/news/fullstory_159014.html Hormone May Be Linked to Teenage Obesity Researchers suspect ... may have lower levels of a weight-regulating hormone than normal-weight teens, a new study says. " ...

  5. Sex hormone binding globulin phenotypes

    DEFF Research Database (Denmark)

    Cornelisse, M M; Bennett, Patrick; Christiansen, M;

    1994-01-01

    Human sex hormone binding globulin (SHBG) is encoded by a normal and a variant allele. The resulting SHBG phenotypes (the homozygous normal SHBG, the heterozygous SHBG and the homozygous variant SHBG phenotype) can be distinguished by their electrophoretic patterns. We developed a novel detection...

  6. Parathyroid hormone and bone healing

    DEFF Research Database (Denmark)

    Ellegaard, M; Jørgensen, N R; Schwarz, P

    2010-01-01

    , no pharmacological treatments are available. There is therefore an unmet need for medications that can stimulate bone healing. Parathyroid hormone (PTH) is the first bone anabolic drug approved for the treatment of osteoporosis, and intriguingly a number of animal studies suggest that PTH could be beneficial...

  7. Hormonal crosstalk in plant immunity

    NARCIS (Netherlands)

    van der Does, A.

    2012-01-01

    The plant hormones salicylic acid (SA), also known as plant aspirin, and jasmonic acid (JA) play major roles in the regulation of the plant immune system. In general, SA is important for defense against pathogens with a biotrophic lifestyle, whereas JA is essential for defense against insect herbivo

  8. Hormonal contraceptives and venous thrombosis

    NARCIS (Netherlands)

    Stegeman, Berendina Hendrika (Bernardine)

    2013-01-01

    Oral contraceptive use is associated with venous thrombosis. However, the mechanism behind this remains unclear. The aim of this thesis was to evaluate genetic variation in the first-pass metabolism of contraceptives, to identify the clinical implications of hormonal contraceptive use after a thromb

  9. Hormonal determinants of pubertal growth.

    NARCIS (Netherlands)

    Delamarre-van Waal, H.A.; Coeverden, S.C. van; Rotteveel, J.J.

    2001-01-01

    Pubertal growth results from increased sex steroid and growth hormone (GH) secretion. Estrogens appear to play an important role in the regulation of pubertal growth in both girls and boys. In girls, however, estrogens cannot be the only sex steroids responsible for pubertal growth, as exogenous est

  10. Pulsatile flow characterization in a vessel phantom with elastic wall using ultrasonic particle image velocimetry technique: the impact of vessel stiffness on flow dynamics.

    Science.gov (United States)

    Qian, Ming; Niu, Lili; Wong, Kelvin Kian Loong; Abbott, Derek; Zhou, Qifa; Zheng, Hairong

    2014-09-01

    This study aims to experimentally investigate the impact of vessel stiffness on the flow dynamics of pulsatile vascular flow. Vessel phantoms with elastic walls were fabricated using polyvinyl alcohol cryogel to result in stiffness ranging from 60.9 to 310.3 kPa and tested with pulsatile flows using a flow circulation set-up. Two-dimensional instantaneous and time-dependent flow velocity and shear rate vector fields were measured using ultrasonic particle image velocimetry (EchoPIV). The waveforms of peak velocities measured by EchoPIV were compared with the ultrasonic pulse Doppler spectrum, and the measuring accuracy was validated. The cyclic vessel wall motion and flow pressure were obtained as well. The results showed that vessel stiffening influenced the waveforms resulting from vessel wall distension and flow pressure, and the fields of flow velocity and shear rate. The stiffer vessel had smaller inner diameter variation, larger pulse pressure and median pressure. The velocity and shear rate maximized at peak systole for all vessels. The results showed a decrease in wall shear stress for a stiffer vessel, which can initiate the atherosclerotic process. Our study elucidates the impact of vessel stiffness on several flow dynamic parameters, and also demonstrates the EchoPIV technique to be a useful and powerful tool in cardiovascular research.

  11. The Barrier Within: Endothelial Transport of Hormones

    OpenAIRE

    Kolka, Cathryn M.; Richard N Bergman

    2012-01-01

    Hormones are involved in a plethora of processes including development and growth, metabolism, mood, and immune responses. These essential functions are dependent on the ability of the hormone to access its target tissue. In the case of endocrine hormones that are transported through the blood, this often means that the endothelium must be crossed. Many studies have shown that the concentrations of hormones and nutrients in blood can be very different from those surrounding the cells on the t...

  12. Influence of ovarian hormones on urogenital infection

    OpenAIRE

    Sonnex, C

    1998-01-01

    Numerous studies have examined the influence of hormones on infectious diseases and there is now a wealth of data relating to the more specific effect of the sex hormones, oestrogen and progesterone, on urogenital infections. The interaction between these hormones and the immune system is complex and the variation of hormonal effect between species further complicates the true picture as related to humans. Although it is difficult therefore to draw general conclusions regarding predomin...

  13. Developing a model of plant hormone interactions

    OpenAIRE

    Wang, Yu Hua; Helen R Irving

    2011-01-01

    Plant growth and development is influenced by mutual interactions among plant hormones. The five classical plant hormones are auxins, cytokinins, gibberellins, abscisic acid and ethylene. They are small diffusible molecules that easily penetrate between cells. In addition, newer classes of plant hormones have been identified such as brassinosteroids, jasmonic acid, salicylic acid and various small proteins or peptides. These hormones also play important roles in the regulation of plant growth...

  14. Endocrine disruptors and thyroid hormone physiology

    OpenAIRE

    Jugan, Mary-Line; Levi, Yves; Blondeau, Jean-Paul

    2010-01-01

    Abstract Endocrine disruptors are man-made chemicals that can disrupt the synthesis, circulating levels, and peripheral action of hormones. The disruption of sex hormones was subject of intensive research, but thyroid hormone synthesis and signaling are now also recognized as important targets of endocrine disruptors. The neurological development of mammals is largely dependent on normal thyroid hormone homeostasis, and it is likely to be particularly sensitive to disruption of the...

  15. Interactions between intakes of alcohol and postmenopausal hormones on risk of breast cancer

    DEFF Research Database (Denmark)

    Nielsen, Naja Rod; Grønbaek, Morten

    2008-01-01

    Alcohol and postmenopausal hormone use are well-established modifiable risk factors for breast cancer. Alcohol may decrease the metabolic clearance of estradiol, whereby the risk of breast cancer associated with hormone use may depend on blood alcohol levels. The objective is to determine whether...... alcohol interacts with hormone use on risk of breast cancer. The 5,035 postmenopausal women who participated in the Copenhagen City Heart Study were asked about their alcohol intake and hormone use at baseline in 1981-1983 and were followed until 2002 in the Danish cancer registry, with ... to follow-up. Proportional hazard models were used to analyze data. During follow-up, 267 women developed breast cancer. Alcohol consumption was associated with a small increased risk of breast cancer (hazard ratio = 1.11 per drink/day, 95% CI: 0.99-1.25). Women who used hormones also had a higher risk...

  16. Analyzing Valuation Practices through Contracts

    DEFF Research Database (Denmark)

    Tesnière, Germain; Labatut, Julie; Boxenbaum, Eva

    This paper seeks to analyze the most recent changes in how societies value animals. We analyze this topic through the prism of contracts between breeding companies and farmers. Focusing on new valuation practices and qualification of breeding animals, we question the evaluation of difficult...... commensurable entities (animal, embryo, mating) and the impacts of these valuation and qualifications on government of living entities....

  17. Analyzing data files in SWAN

    CERN Document Server

    Gajam, Niharika

    2016-01-01

    Traditionally analyzing data happens via batch-processing and interactive work on the terminal. The project aims to provide another way of analyzing data files: A cloud-based approach. It aims to make it a productive and interactive environment through the combination of FCC and SWAN software.

  18. Melatonin effects on luteinizing hormone in postmenopausal women: a pilot clinical trial NCT00288262

    Directory of Open Access Journals (Sweden)

    Kline Lawrence E

    2006-05-01

    Full Text Available Abstract Background In many mammals, the duration of the nocturnal melatonin elevation regulates seasonal changes in reproductive hormones such as luteinizing hormone (LH. Melatonin's effects on human reproductive endocrinology are uncertain. It is thought that the same hypothalamic pulse generator may both trigger the pulsatile release of GnRH and LH and also cause hot flashes. Thus, if melatonin suppressed this pulse generator in postmenopausal women, it might moderate hot flashes. This clinical trial tested the hypothesis that melatonin could suppress LH and relieve hot flashes. Methods Twenty postmenopausal women troubled by hot flashes underwent one week of baseline observation followed by 4 weeks of a randomized controlled trial of melatonin or matched placebo. The three randomized treatments were melatonin 0.5 mg 2.5–3 hours before bedtime, melatonin 0.5 mg upon morning awakening, or placebo capsules. Twelve of the women were admitted to the GCRC at baseline and at the end of randomized treatment for 24-hour sampling of blood for LH. Morning urine samples were collected twice weekly to measure LH excretion. Subjective responses measured throughout baseline and treatment included sleep and hot flash logs, the CESD and QIDS depression self-ratings, and the SAFTEE physical symptom inventory. Results Urinary LH tended to increase from baseline to the end of treatment. Contrasts among the 3 randomized groups were statistically marginal, but there was relative suppression combining the groups given melatonin as contrasted to the placebo group (p Conclusion The data are consistent with the hypothesis that melatonin suppresses LH in postmenopausal women. An effect related to the duration of nocturnal melatonin elevation is suggested. Effects of melatonin on reproductive endocrinology should be studied further in younger women and in men. Larger studies of melatonin effects on postmenopausal symptoms would be worthwhile.

  19. "Sex Hormones" in Secondary School Biology Textbooks

    Science.gov (United States)

    Nehm, Ross H.; Young, Rebecca

    2008-01-01

    This study explores the extent to which the term "sex hormone" is used in science textbooks, and whether the use of the term "sex hormone" is associated with pre-empirical concepts of sex dualism, in particular the misconceptions that these so-called "sex hormones" are sex specific and restricted to sex-related physiological functioning. We found…

  20. Peptide Hormones in the Gastrointestinal Tract

    DEFF Research Database (Denmark)

    Rehfeld, Jens F.

    2015-01-01

    Gastrointestinal hormones are peptides released from endocrine cells and neurons in the digestive tract. More than 30 hormone genes are currently known to be expressed in the gastrointestinal tract, which makes the gut the largest hormone-producing organ in the body. Modern biology makes it feasi...

  1. The hormonal regulation of life processes in insects (2.) The anti-juvenile hormones (1.)

    International Nuclear Information System (INIS)

    Those compounds that decrease either the level or activity of natural endogenous juvenile hormones in insects are called anti-juvenile hormones (AJH). The possible effects of anti-juvenile hormones are manifold: they may inhibit special enzymes or the bindings of juvenile hormones to receptors and transport proteins or may cause the destruction of corpora allata, the sources of juvenile hormones. The most obvious possibility to elicit an anti-juvenile hormone effect lies in the inhibition of enzymes participating in the biosynthesis of juvenile hormones

  2. Nuclear fuel microsphere gamma analyzer

    Science.gov (United States)

    Valentine, Kenneth H.; Long, Jr., Ernest L.; Willey, Melvin G.

    1977-01-01

    A gamma analyzer system is provided for the analysis of nuclear fuel microspheres and other radioactive particles. The system consists of an analysis turntable with means for loading, in sequence, a plurality of stations within the turntable; a gamma ray detector for determining the spectrum of a sample in one section; means for analyzing the spectrum; and a receiver turntable to collect the analyzed material in stations according to the spectrum analysis. Accordingly, particles may be sorted according to their quality; e.g., fuel particles with fractured coatings may be separated from those that are not fractured, or according to other properties.

  3. Growth hormone state after completion of treatment with growth hormone.

    OpenAIRE

    Clayton, P E; Price, D. A.; Shalet, S M

    1987-01-01

    After completion of treatment with growth hormone (GH) 19 patients with isolated 'idiopathic' GH deficiency and 15 with post-irradiation GH deficiency underwent retesting of GH secretion with an insulin tolerance test or an arginine stimulation test, or both. Patients with post-irradiation GH deficiency comprised 13 patients with central nervous system tumours distant from the hypothalamo-pituitary axis and two with acute lymphoblastic leukaemia, who had received cranial or craniospinal irrad...

  4. Thyroid hormone receptors bind to defined regions of the growth hormone and placental lactogen genes.

    OpenAIRE

    Barlow, J W; Voz, M L; Eliard, P H; Mathy-Harter, M; De Nayer, Philippe; Economidis, I V; Belayew, A; Martial, J A; Rousseau, Guy

    1986-01-01

    The intracellular receptor for thyroid hormone is a protein found in chromatin. Since thyroid hormone stimulates transcription of the growth hormone gene through an unknown mechanism, the hypothesis that the thyroid hormone-receptor complex interacts with defined regions of this gene has been investigated in a cell-free system. Nuclear extracts from human lymphoblastoid IM-9 cells containing thyroid hormone receptors were incubated with L-3,5,3'-tri[125I]iodothyronine and calf thymus DNA-cell...

  5. The menopause and hormone replacement therapy: views of women in general practice receiving hormone replacement therapy.

    OpenAIRE

    Roberts, P J

    1991-01-01

    Women's views on the menopause and hormone replacement therapy were explored using a questionnaire given to women attending one general practice who were having hormone replacement therapy under the supervision of their doctor. Sixty four women (67%) responded. Although only 5% of women had requested hormone replacement therapy from their general practitioner the majority of women indicated that they had been helped by hormone replacement therapy. Eight per cent of women were using hormone re...

  6. Reproductive Hormones and Mood Disorders

    Directory of Open Access Journals (Sweden)

    Sermin Kesebir

    2010-12-01

    Full Text Available During the menstrual cycle, pregnancy and breast-feeding periods, as well as in menopausal and post-menopausal periods, the physiological and psychological processes that change according to the hormonal fluctuations influence every women similarly and each one differently. These physiological processes are controlled by neuroendocrine sequences, of which the hypothalamo-pituitary-adrenal axis and the hypothalamo-pituitary-gonadal axis are the most important ones. The hypothalamo-pituitary-gonadal axis affects mood, anxiety, cognition and pain. The interaction of these hormones with mood and behavior is bidirectional. The differences in phenomenology and epidemiology of mood disorders with regards to gender can be explained with the effects of hormones. All of the periods mentioned above are related with mood disorders at terms of risk factors, disease symptoms, progress of disease and response to treatment. Epidemiologic data supports the relationship between the mood disorders and reproductive processes. The prevalence of major depression increases in women with the menarche and ceases in post- menopausal period. Similarly, the initial symptoms of bipolar disorder begins around the menarche period in 50% of the cases. Despite proper treatment, some female patients with major depression experience recurrence during the premenstrual period of their menstrual cycles. The conformity and change in a woman’s brain during pregnancy is controlled dominantly by the neuroendocrine systems, while it is controlled by the external stimuli actively related to the baby during nursing period. The changes that occur are closely related to postpartum mood disorders. Again, all the changes and suspension of medication during this procedure are risk factors for early depressive and dysphoric situations. Variables of a wide range, from follicle stimulating hormone, melatonin, and sleep to body mass index interact with mood disorders in menopausal and post

  7. Effects of EDTA and Sodium Citrate on hormone measurements by fluorometric (FIA and immunofluorometric (IFMA methods

    Directory of Open Access Journals (Sweden)

    Lando Valeria

    2002-05-01

    Full Text Available Abstract Background Measurements of hormonal concentrations by immunoassays using fluorescent tracer substance (Eu3+ are susceptible to the action of chemical agents that may cause alterations in its original structure. Our goal was to verify the effect of two types of anticoagulants in the hormone assays performed by fluorometric (FIA or immunofluorometric (IFMA methods. Methods Blood samples were obtained from 30 outpatients and were drawn in EDTA, sodium citrate, and serum separation Vacutainer®Blood Collection Tubes. Samples were analyzed in automatized equipment AutoDelfia™ (Perkin Elmer Brazil, Wallac, Finland for the following hormones: Luteinizing hormone (LH, Follicle stimulating homone (FSH, prolactin (PRL, growth hormone (GH, Sex hormone binding globulin (SHBG, thyroid stimulating hormone (TSH, insulin, C peptide, total T3, total T4, free T4, estradiol, progesterone, testosterone, and cortisol. Statistical analysis was carried out by Kruskal-Wallis method and Dunn's test. Results No significant differences were seen between samples for LH, FSH, PRL and free T4. Results from GH, TSH, insulin, C peptide, SHBG, total T3, total T4, estradiol, testosterone, cortisol, and progesterone were significant different between serum and EDTA-treated samples groups. Differences were also identified between serum and sodium citrate-treated samples in the analysis for TSH, insulin, total T3, estradiol, testosterone and progesterone. Conclusions We conclude that the hormonal analysis carried through by FIA or IFMA are susceptible to the effects of anticoagulants in the biological material collected that vary depending on the type of assay.

  8. Hormonal treatment of acne vulgaris: an update.

    Science.gov (United States)

    Elsaie, Mohamed L

    2016-01-01

    Acne vulgaris is a common skin condition associated with multiple factors. Although mostly presenting alone, it can likewise present with features of hyperandrogenism and hormonal discrepancies. Of note, hormonal therapies are indicated in severe, resistant-to-treatment cases and in those with monthly flare-ups and when standard therapeutic options are inappropriate. This article serves as an update to hormonal pathogenesis of acne, discusses the basics of endocrinal evaluation for patients with suspected hormonal acne, and provides an overview of the current hormonal treatment options in women. PMID:27621661

  9. Hormonal treatment of acne vulgaris: an update

    Science.gov (United States)

    Elsaie, Mohamed L

    2016-01-01

    Acne vulgaris is a common skin condition associated with multiple factors. Although mostly presenting alone, it can likewise present with features of hyperandrogenism and hormonal discrepancies. Of note, hormonal therapies are indicated in severe, resistant-to-treatment cases and in those with monthly flare-ups and when standard therapeutic options are inappropriate. This article serves as an update to hormonal pathogenesis of acne, discusses the basics of endocrinal evaluation for patients with suspected hormonal acne, and provides an overview of the current hormonal treatment options in women. PMID:27621661

  10. Analysis of Paired Primary-Metastatic Hormone-Receptor Positive Breast Tumors (HRPBC Uncovers Potential Novel Drivers of Hormonal Resistance.

    Directory of Open Access Journals (Sweden)

    Luis Manso

    Full Text Available We sought to identify genetic variants associated with disease relapse and failure to hormonal treatment in hormone-receptor positive breast cancer (HRPBC. We analyzed a series of HRPBC with distant relapse, by sequencing pairs (n = 11 of tumors (primary and metastases at >800X. Comparative genomic hybridization was performed as well. Top hits, based on the frequency of alteration and severity of the changes, were tested in the TCGA series. Genes determining the most parsimonious prognostic signature were studied for their functional role in vitro, by performing cell growth assays in hormonal-deprivation conditions, a setting that mimics treatment with aromatase inhibitors. Severe alterations were recurrently found in 18 genes in the pairs. However, only MYC, DNAH5, CSFR1, EPHA7, ARID1B, and KMT2C preserved an independent prognosis impact and/or showed a significantly different incidence of alterations between relapsed and non-relapsed cases in the TCGA series. The signature composed of MYC, KMT2C, and EPHA7 best discriminated the clinical course, (overall survival 90,7 vs. 144,5 months; p = 0.0001. Having an alteration in any of the genes of the signature implied a hazard ratio of death of 3.25 (p<0.0001, and early relapse during the adjuvant hormonal treatment. The presence of the D348N mutation in KMT2C and/or the T666I mutation in the kinase domain of EPHA7 conferred hormonal resistance in vitro. Novel inactivating mutations in KMT2C and EPHA7, which confer hormonal resistance, are linked to adverse clinical course in HRPBC.

  11. Lutropin alpha, recombinant human luteinizing hormone, for the stimulation of follicular development in profoundly LH-deficient hypogonadotropic hypogonadal women: a review

    Directory of Open Access Journals (Sweden)

    Bernd Th Krause

    2009-06-01

    Full Text Available Bernd Th Krause1, Ralf Ohlinger2, Annette Haase31Center for Endocrinology and Reproductive Medicine, MVZ Uhlandstr, Berlin, Germany; 2Ernst-Moritz-Arndt-University, Department of Gynecology and Obstetrics, Greifswald, Germany; 3Uhlandstr. 162, 10719 BerlinAbstract: Hypogonadotropic hypogonadism is defined as a medical condition with low or undetectable gonadotropin secretion, associated with a complete arrest of follicular growth and very low estradiol. The main cause can be traced back to an irregular or absent hypothalamic GnRH secretion, whereas only a minority suffers from a pituitary disorder. The choice of treatment to reverse this situation is a pulsatile GnRH application or a direct ovarian stimulation using gonadotropin injections. The goal is to achieve a proper ovarian function in these cases for a short time to allow ovulation and chance of pregnancy. Since the pulsatile GnRH treatment lost its former importance, several gonadotropins are in use to stimulate follicular growth, such as urine-derived human menopausal gonadotropin, highly purified follicle stimulating hormone (FSH or recombinant FSH, all with different success. The introduction of recombinant luteinizing hormone (LH and FSH provided an opportunity to investigate the distinct influences of LH and FSH alone and in combination on follicular growth in monofollicular ovulation induction cycles, and additionally on oocyte maturation, fertilization competence of the oocyte and embryo quality in downregulated IVF patients. Whereas FSH was known to be indispensable for normal follicular growth, the role of LH remained questionable. Downregulated IVF patients with this short-term gonadotropin depletion displayed no advance in stimulation success with the use of recombinant LH. Patients with hypogonadotropic hypogonadism undergoing monofollicular stimulation for ovulation induction showed clearly a specific role and need for both hormones in normal follicular growth. Therefore, a

  12. 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 ...

  13. Hormonal contraception, thrombosis and age

    DEFF Research Database (Denmark)

    Lidegaard, Øjvind

    2014-01-01

    INTRODUCTION: This paper reviews the risk of thrombosis with use of different types of hormonal contraception in women of different ages. AREAS COVERED: Combined hormonal contraceptives with desogestrel, gestodene, drospirenone or cyproterone acetate (high-risk products) confer a sixfold increased......: First choice in women below 35 years should be a combined low-risk pill, that is, with a second-generation progestin, with the lowest compliable dose of estrogen. Young women with risk factors of thrombosis such as age above 35 years, genetic predispositions, adiposity, polycystic ovary syndrome......, diabetes, smoking, hypertension or migraine with aura should not use high-risk products, but should primarily consider progestin-only products, and be careful to use low-risk combined products....

  14. Radioactive labelling of peptidic hormones

    International Nuclear Information System (INIS)

    The labelling of peptidic hormones requires stability, specificity and sensitivity of the label. Introduction of a radioactive atome is one way to satisfy these criteria. Several processes have been described to prepare radioactive TRF: synthesis of the peptide with labelled aminoacids or introduction of the label into the hormone. In that approach, tritium can be substituted in the imidazole ring, via precursors activating the proper carbon. Monoiodo TRF leads essentially to tritium labelling of the 5 positions whereas monoazo TRF allows the preparation of 3H TRF labelled in the 2 positions. Di-substituted TRF leads to labelling into the 2 and 5 carbons. Labelled analogs of TRF can be prepared with labelled iodine; further developments of peptide labelling, will be presented. In particular, the homolytic scission of the C-iodine, bond by photochemical activation. The nascent carbon radical can be stabilized by a tritiated scavenger. This approach eliminates the use of heavy metal catalysts

  15. Growth hormone and its disorders

    OpenAIRE

    Ayuk, J.; Sheppard, M C

    2006-01-01

    Growth hormone (GH) is synthesised and secreted by the somatotroph cells of the anterior lobe of the pituitary gland. Its actions involve multiple organs and systems, affecting postnatal longitudinal growth as well as protein, lipid, and carbohydrate metabolism. GH hypersecretion results in gigantism or acromegaly, a condition associated with significant morbidity and mortality, while GH deficiency results in growth retardation in children and the GH deficiency syndrome in adults. This articl...

  16. Parathyroid Hormone Levels and Cognition

    Science.gov (United States)

    Burnett, J.; Smith, S.M.; Aung, K.; Dyer, C.

    2009-01-01

    Hyperparathyroidism is a well-recognized cause of impaired cognition due to hypercalcemia. However, recent studies have suggested that perhaps parathyroid hormone itself plays a role in cognition, especially executive dysfunction. The purpose of this study was to explore the relationship of parathyroid hormone levels in a study cohort of elders with impaied cognition. Methods: Sixty community-living adults, 65 years of age and older, reported to Adult Protective Services for self-neglect and 55 controls matched (on age, ethnicity, gender and socio-economic status) consented and participated in this study. The research team conducted in-home comprehensive geriatric assessments which included the Mini-mental state exam (MMSE), the 15-item geriatric depression scale (GDS) , the Wolf-Klein clock test and a comprehensive nutritional panel, which included parathyroid hormone and ionized calcium. Students t tests and linear regression analyses were performed to assess for bivariate associations. Results: Self-neglecters (M = 73.73, sd=48.4) had significantly higher PTH levels compared to controls (M =47.59, sd=28.7; t=3.59, df=98.94, plevels. Overall, PTH was correlated with the MMSE (r=-.323, p=.001). Individual regression analyses revealed a statistically significant correlation between PTH and MMSE in the self-neglect group (r=-.298, p=.024) and this remained significant after controlling for ionized calcium levels in the regression. No significant associations were revealed in the control group or among any of the other cognitive measures. Conclusion: Parathyroid hormone may be associated with cognitive performance.

  17. Reproductive Hormones and Mood Disorders

    OpenAIRE

    Sermin Kesebir; Arzu Etlik Aksoy

    2010-01-01

    During the menstrual cycle, pregnancy and breast-feeding periods, as well as in menopausal and post-menopausal periods, the physiological and psychological processes that change according to the hormonal fluctuations influence every women similarly and each one differently. These physiological processes are controlled by neuroendocrine sequences, of which the hypothalamo-pituitary-adrenal axis and the hypothalamo-pituitary-gonadal axis are the most important ones. The hypothalamo-pituitary-go...

  18. Growth hormone, inflammation and aging

    Directory of Open Access Journals (Sweden)

    Michal M. Masternak

    2012-04-01

    Full Text Available Mutant animals characterized by extended longevity provide valuable tools to study the mechanisms of aging. Growth hormone and insulin-like growth factor-1 (IGF-1 constitute one of the well-established pathways involved in the regulation of aging and lifespan. Ames and Snell dwarf mice characterized by GH deficiency as well as growth hormone receptor/growth hormone binding protein knockout (GHRKO mice characterized by GH resistance live significantly longer than genetically normal animals. During normal aging of rodents and humans there is increased insulin resistance, disruption of metabolic activities and decline of the function of the immune system. All of these age related processes promote inflammatory activity, causing long term tissue damage and systemic chronic inflammation. However, studies of long living mutants and calorie restricted animals show decreased pro-inflammatory activity with increased levels of anti-inflammatory adipokines such as adiponectin. At the same time, these animals have improved insulin signaling and carbohydrate homeostasis that relate to alterations in the secretory profile of adipose tissue including increased production and release of anti-inflammatory adipokines. This suggests that reduced inflammation promoting healthy metabolism may represent one of the major mechanisms of extended longevity in long-lived mutant mice and likely also in the human.

  19. Thyroid hormone and seasonal rhythmicity

    Directory of Open Access Journals (Sweden)

    Hugues eDardente

    2014-02-01

    Full Text Available Living organisms show seasonality in a wide array of functions such as reproduction, fattening, hibernation and migration. At temperate latitudes, changes in photoperiod maintain the alignment of annual rhythms with predictable changes in the environment. The appropriate physiological response to changing photoperiod in mammals requires retinal detection of light and pineal secretion of melatonin, but extraretinal detection of light occurs in birds. A common mechanism across all vertebrates is that these photoperiod-regulated systems alter hypothalamic thyroid hormone conversion. Here we review the evidence that a circadian clock within the pars tuberalis of the adenohypophysis links photoperiod decoding to local changes of thyroid hormone signalling within the medio-basal hypothalamus through a conserved thyrotropin/deiodinase axis. We also focus on recent findings which indicate that, beyond the photoperiodic control of its conversion, thyroid hormone might also be involved in longer term timing processes of seasonal programs. Finally, we examine the potential implication of kisspeptin and RFRP3, two RF-amide peptides expressed within the medio-basal hypothalamus, in seasonal rhythmicity.

  20. SU-D-18C-04: The Feasibility of Quantifying MRI Contrast Agent in Pulsatile Flowing Blood Using DCE-MRI

    Energy Technology Data Exchange (ETDEWEB)

    N, Gwilliam M; J, Collins D; O, Leach M; R, Orton M [Institute of Cancer Research, London (United Kingdom)

    2014-06-01

    Purpose: To assess the feasibility of accurately quantifying the concentration of MRI contrast agent (CA) in pulsatile flowing blood by measuring its T{sub 1}, as is common for the purposes of obtaining a patientspecific arterial input function (AIF). Dynamic contrast enhanced (DCE) - MRI and pharmacokinetic (PK) modelling is widely used to produce measures of vascular function but accurate measurement of the AIF undermines their accuracy. A proposed solution is to measure the T{sub 1} of blood in a large vessel using the Fram double flip angle method during the passage of a bolus of CA. This work expands on previous work by assessing pulsatile flow and the changes in T{sub 1} seen with a CA bolus. Methods: A phantom was developed which used a physiological pump to pass fluid of a known T{sub 1} (812ms) through the centre of a head coil of a clinical 1.5T MRI scanner. Measurements were made using high temporal resolution sequences suitable for DCE-MRI and were used to validate a virtual phantom that simulated the expected errors due to pulsatile flow and bolus of CA concentration changes typically found in patients. Results: : Measured and virtual results showed similar trends, although there were differences that may be attributed to the virtual phantom not accurately simulating the spin history of the fluid before entering the imaging volume. The relationship between T{sub 1} measurement and flow speed was non-linear. T{sub 1} measurement is compromised by new spins flowing into the imaging volume, not being subject to enough excitations to have reached steady-state. The virtual phantom demonstrated a range of recorded T{sub 1} for various simulated T{sub 1} / flow rates. Conclusion: T{sub 1} measurement of flowing blood using standard DCE-MRI sequences is very challenging. Measurement error is non-linear with relation to instantaneous flow speed. Optimising sequence parameters and lowering baseline T{sub 1} of blood should be considered.

  1. BLOOD METABOLIC HORMONES AND LEPTIN IN GROWING LAMBS

    Directory of Open Access Journals (Sweden)

    Zvonko Antunović

    2010-12-01

    Full Text Available The aim of this paper is to determine the concentration of blood metabolic hormones and leptin levels in growing lambs. The research was carried out on Tsigai lambs in two periods (suckling and fattening during the winter feeding season. Lambs were suckling and ate a food mixture and alfalfa hay ad libitum, while during the fattening period they were fed only with the above mentioned mixture and alfalfa hay ad libitum. Their blood was analyzed on 35th and 75th day of age. Concentrations of minsulin, leptin and thyroid hormones were determined in the blood serum of lambs during both periods. In the blood of fattening lambs significantly higher (P0.05 insulin concentrations (1.05 and 0.54 μU/mL, were determined, compared to suckling lambs. A significant strong positive correlation between serum leptin and insulin (r = 0.85, P0.05. The concentration of thyroid hormones did not significantly differ depending on the period of measurement. These changes indicate that the measurement concentrations of metabolic hormones and leptin in blood are very important in order to understand the changes of metabolism and nutrient supply in growing lambs.

  2. Hormonal Regulation and Expression Profiles of Wheat Genes Involved during Phytic Acid Biosynthesis Pathway

    OpenAIRE

    Sipla Aggarwal; Vishnu Shukla; Kaushal Kumar Bhati; Mandeep Kaur; Shivani Sharma; Anuradha Singh; Shrikant Mantri; Ajay Kumar Pandey

    2015-01-01

    Phytic acid (PA) biosynthesis pathway genes were reported from multiple crop species. PA accumulation was enhanced during grain filling and at that time, hormones like Abscisic acid (ABA) and Gibberellic acid (GA3) interplay to control the process of seed development. Regulation of wheat PA pathway genes has not yet been reported in seeds. In an attempt to find the clues for the regulation by hormones, the promoter region of wheat PA pathway genes was analyzed for the presence of cis-elements...

  3. The Biological Effects of Sex Hormones on Rabbit Articular Chondrocytes from Different Genders

    OpenAIRE

    Shwu Jen Chang; Shyh Ming Kuo; Yen Ting Lin; Shan-Wei Yang

    2014-01-01

    The aim of this study was to investigate the biological effects of sex hormones (17 β -estradiol and testosterone) on rabbit articular chondrocytes from different genders. We cultured primary rabbit articular chondrocytes from both genders with varying concentration of sex hormones. We evaluate cell proliferation and biochemical functions by MTT and GAG assay. The chondrocyte function and phenotypes were analyzed by mRNA level using RT-PCR. Immunocytochemical staining was also used to evaluat...

  4. Loviisa nuclear power plant analyzer

    International Nuclear Information System (INIS)

    The APROS Simulation Environment has been developed since 1986 by Imatran Voima Oy (IVO) and the Technical Research Centre of Finland (VTT). It provides tools, solution algorithms and process components for use in different simulation systems for design, analysis and training purposes. One of its main nuclear applications is the Loviisa Nuclear Power Plant Analyzer (LPA). The Loviisa Plant Analyzer includes all the important plant components both in the primary and in the secondary circuits. In addition, all the main control systems, the protection system and the high voltage electrical systems are included. (orig.)

  5. Analyzing the Grammar of English

    CERN Document Server

    Teschner, Richard V

    2007-01-01

    Analyzing the Grammar of English offers a descriptive analysis of the indispensable elements of English grammar. Designed to be covered in one semester, this textbook starts from scratch and takes nothing for granted beyond a reading and speaking knowledge of English. Extensively revised to function better in skills-building classes, it includes more interspersed exercises that promptly test what is taught, simplified and clarified explanations, greatly expanded and more diverse activities, and a new glossary of over 200 technical terms.Analyzing the Grammar of English is the only English gram

  6. The Convertible Arbitrage Strategy Analyzed

    NARCIS (Netherlands)

    Loncarski, I.; Ter Horst, J.R.; Veld, C.H.

    2006-01-01

    This paper analyzes convertible bond arbitrage on the Canadian market for the period 1998 to 2004.Convertible bond arbitrage is the combination of a long position in convertible bonds and a short position in the underlying stocks. Convertible arbitrage has been one of the most successful strategies

  7. Software-Design-Analyzer System

    Science.gov (United States)

    Tausworthe, Robert C.

    1991-01-01

    CRISP-90 software-design-analyzer system, update of CRISP-80, is set of computer programs constituting software tool for design and documentation of other software and supporting top-down, hierarchical, modular, structured methodologies for design and programming. Written in Microsoft QuickBasic.

  8. FORTRAN Static Source Code Analyzer

    Science.gov (United States)

    Merwarth, P.

    1984-01-01

    FORTRAN Static Source Code Analyzer program, SAP (DEC VAX version), automatically gathers statistics on occurrences of statements and structures within FORTRAN program and provides reports of those statistics. Provisions made for weighting each statistic and provide an overall figure of complexity.

  9. Pulsatile flow and heat transfer of a magneto-micropolar fluid through a stenosed artery under the influence of body acceleration

    CERN Document Server

    Shit, G C

    2012-01-01

    With an aim to investigate the effect of externally imposed body acceleration and magnetic field on pulsatile flow of blood through an arterial segment having stenosis is under consideration in this paper. The flow of blood is presented by a unsteady micropolar fluid and the heat transfer characteristics have been taken into account. The non-linear equations that governing the flow are solved numerically using finite difference technique by employing a suitable coordinate transformation. The numerical results have been observed for axial and microrotation component of velocity, fluid acceleration, wall shear stress(WSS), flow resistance, temperature and the volumetric flow rate. It thus turns out that the rate of heat transfer increases with the increase of Hartmann number $H$, while the wall shear stress has a reducing effect on the Hartmann number $H$ and an enhancing effect on microrotation parameter $K$ as well as the constriction height $\\delta$.

  10. Effect of growth hormone replacement therapy on pituitary hormone secretion and hormone replacement therapies in GHD adults

    DEFF Research Database (Denmark)

    Hubina, Erika; Mersebach, Henriette; Rasmussen, Ase Krogh;

    2004-01-01

    We tested the impact of commencement of GH replacement therapy in GH-deficient (GHD) adults on the circulating levels of other anterior pituitary and peripheral hormones and the need for re-evaluation of other hormone replacement therapies, especially the need for dose changes.......We tested the impact of commencement of GH replacement therapy in GH-deficient (GHD) adults on the circulating levels of other anterior pituitary and peripheral hormones and the need for re-evaluation of other hormone replacement therapies, especially the need for dose changes....

  11. Methods for Analyzing Social Media

    DEFF Research Database (Denmark)

    Jensen, Jakob Linaa

    2013-01-01

    Social media is becoming increasingly attractive for users. It is a fast way to communicate ideas and a key source of information. It is therefore one of the most influential mediums of communication of our time and an important area for audience research. The growth of social media invites many...... new questions such as: How can we analyze social media? Can we use traditional audience research methods and apply them to online content? Which new research strategies have been developed? Which ethical research issues and controversies do we have to pay attention to? This book focuses on research...... strategies and methods for analyzing social media and will be of interest to researchers and practitioners using social media, as well as those wanting to keep up to date with the subject....

  12. Introduction: why analyze single cells?

    Science.gov (United States)

    Di Carlo, Dino; Tse, Henry Tat Kwong; Gossett, Daniel R

    2012-01-01

    Powerful methods in molecular biology are abundant; however, in many fields including hematology, stem cell biology, tissue engineering, and cancer biology, data from tools and assays that analyze the average signals from many cells may not yield the desired result because the cells of interest may be in the minority-their behavior masked by the majority-or because the dynamics of the populations of interest are offset in time. Accurate characterization of samples with high cellular heterogeneity may only be achieved by analyzing single cells. In this chapter, we discuss the rationale for performing analyses on individual cells in more depth, cover the fields of study in which single-cell behavior is yielding new insights into biological and clinical questions, and speculate on how single-cell analysis will be critical in the future.

  13. The Statistical Loop Analyzer (SLA)

    Science.gov (United States)

    Lindsey, W. C.

    1985-01-01

    The statistical loop analyzer (SLA) is designed to automatically measure the acquisition, tracking and frequency stability performance characteristics of symbol synchronizers, code synchronizers, carrier tracking loops, and coherent transponders. Automated phase lock and system level tests can also be made using the SLA. Standard baseband, carrier and spread spectrum modulation techniques can be accomodated. Through the SLA's phase error jitter and cycle slip measurements the acquisition and tracking thresholds of the unit under test are determined; any false phase and frequency lock events are statistically analyzed and reported in the SLA output in probabilistic terms. Automated signal drop out tests can be performed in order to trouble shoot algorithms and evaluate the reacquisition statistics of the unit under test. Cycle slip rates and cycle slip probabilities can be measured using the SLA. These measurements, combined with bit error probability measurements, are all that are needed to fully characterize the acquisition and tracking performance of a digital communication system.

  14. Satellite-based interference analyzer

    Science.gov (United States)

    Varice, H.; Johannsen, K.; Sabaroff, S.

    1977-01-01

    System identifies terrestrial sources of radiofrequency interference and measures their frequency spectra and amplitudes. Designed to protect satellite communication networks, system measures entire noise spectrum over selected frequency band and can raster-scan geographical region to locate noise sources. Once interference is analyzed, realistic interference protection ratios are determined and mathematical models for predicting ratio-frequency noise spectra are established. This enhances signal-detection and locates optimum geographical positions and frequency bands for communication equipment.

  15. Anabolic hormone profiles in elite military men.

    Science.gov (United States)

    Taylor, Marcus K; Kviatkovsky, Shiloah A; Hernández, Lisa M; Sargent, Paul; Segal, Sabrina; Granger, Douglas A

    2016-06-01

    We recently characterized the awakening responses and daily profiles of the catabolic stress hormone cortisol in elite military men. Anabolic hormones follow a similar daily pattern and may counteract the catabolic effects of cortisol. This companion report is the first to characterize daily profiles of anabolic hormones dehydroepiandrosterone (DHEA) and testosterone in this population. Overall, the men in this study displayed anabolic hormone profiles comparable to that of healthy, athletic populations. Consistent with the cortisol findings in our prior report, summary parameters of magnitude (hormone output) within the first hour after awakening displayed superior stability versus summary parameters of pattern for both DHEA (r range: 0.77-0.82) and testosterone (r range: 0.62-0.69). Summary parameters of evening function were stable for the two hormones (both panabolic balance and resultant effects upon health and human performance in this highly resilient yet chronically stressed population. PMID:27083310

  16. Anabolic hormone profiles in elite military men.

    Science.gov (United States)

    Taylor, Marcus K; Kviatkovsky, Shiloah A; Hernández, Lisa M; Sargent, Paul; Segal, Sabrina; Granger, Douglas A

    2016-06-01

    We recently characterized the awakening responses and daily profiles of the catabolic stress hormone cortisol in elite military men. Anabolic hormones follow a similar daily pattern and may counteract the catabolic effects of cortisol. This companion report is the first to characterize daily profiles of anabolic hormones dehydroepiandrosterone (DHEA) and testosterone in this population. Overall, the men in this study displayed anabolic hormone profiles comparable to that of healthy, athletic populations. Consistent with the cortisol findings in our prior report, summary parameters of magnitude (hormone output) within the first hour after awakening displayed superior stability versus summary parameters of pattern for both DHEA (r range: 0.77-0.82) and testosterone (r range: 0.62-0.69). Summary parameters of evening function were stable for the two hormones (both panabolic balance and resultant effects upon health and human performance in this highly resilient yet chronically stressed population.

  17. Ectopic acromegaly due to growth hormone releasing hormone.

    Science.gov (United States)

    Ghazi, Ali A; Amirbaigloo, Alireza; Dezfooli, Azizollah Abbasi; Saadat, Navid; Ghazi, Siavash; Pourafkari, Marina; Tirgari, Farrokh; Dhall, Dheepti; Bannykh, Serguei; Melmed, Shlomo; Cooper, Odelia

    2013-04-01

    Acromegaly secondary to extra-pituitary tumors secreting growth hormone releasing hormone (GHRH) is rarely encountered. We review the literature on ectopic acromegaly and present the index report of ectopic acromegaly secondary to GHRH secretion from a mediastinal paraganglioma. Clinical and pathological manifestations and therapeutic management of 99 patients with ectopic acromegaly are reviewed. Acromegaly secondary to ectopic GHRH secretion is usually caused by a neuroendocrine tumor in the lung and pancreas. We report an additional cause of ectopic acromegaly from a mediastinal paraganglioma. Diagnostic criteria of ectopic GHRH syndrome include biochemical and pathologic tumoral confirmation of GHRH secretion and expression. Management of ectopic acromegaly consists of surgical resection of the primary tumor and biochemical normalization, with possible adjuvant use of somatostatin analogs. The review demonstrates that there are several tumor types, including paragangliomas which may secrete GHRH, leading to acromegaly. Clinical and laboratory manifestations of the syndrome and challenges in diagnosis and management of these rarely encountered patients require early diagnosis and appropriate treatment to prevent long-term morbidity and mortality with ectopic acromegaly. PMID:22983831

  18. Analyzing Big Data in Psychology: A Split/Analyze/Meta-Analyze Approach.

    Science.gov (United States)

    Cheung, Mike W-L; Jak, Suzanne

    2016-01-01

    Big data is a field that has traditionally been dominated by disciplines such as computer science and business, where mainly data-driven analyses have been performed. Psychology, a discipline in which a strong emphasis is placed on behavioral theories and empirical research, has the potential to contribute greatly to the big data movement. However, one challenge to psychologists-and probably the most crucial one-is that most researchers may not have the necessary programming and computational skills to analyze big data. In this study we argue that psychologists can also conduct big data research and that, rather than trying to acquire new programming and computational skills, they should focus on their strengths, such as performing psychometric analyses and testing theories using multivariate analyses to explain phenomena. We propose a split/analyze/meta-analyze approach that allows psychologists to easily analyze big data. Two real datasets are used to demonstrate the proposed procedures in R. A new research agenda related to the analysis of big data in psychology is outlined at the end of the study.

  19. Analyzing Big Data in Psychology: A Split/Analyze/Meta-Analyze Approach

    Science.gov (United States)

    Cheung, Mike W.-L.; Jak, Suzanne

    2016-01-01

    Big data is a field that has traditionally been dominated by disciplines such as computer science and business, where mainly data-driven analyses have been performed. Psychology, a discipline in which a strong emphasis is placed on behavioral theories and empirical research, has the potential to contribute greatly to the big data movement. However, one challenge to psychologists—and probably the most crucial one—is that most researchers may not have the necessary programming and computational skills to analyze big data. In this study we argue that psychologists can also conduct big data research and that, rather than trying to acquire new programming and computational skills, they should focus on their strengths, such as performing psychometric analyses and testing theories using multivariate analyses to explain phenomena. We propose a split/analyze/meta-analyze approach that allows psychologists to easily analyze big data. Two real datasets are used to demonstrate the proposed procedures in R. A new research agenda related to the analysis of big data in psychology is outlined at the end of the study. PMID:27242639

  20. Analyzing Big Data in Psychology: A Split/Analyze/Meta-Analyze Approach

    Directory of Open Access Journals (Sweden)

    Mike W.-L. Cheung

    2016-05-01

    Full Text Available Big data is a field that has traditionally been dominated by disciplines such as computer science and business, where mainly data-driven analyses have been performed. Psychology, a discipline in which a strong emphasis is placed on behavioral theories and empirical research, has the potential to contribute greatly to the big data movement. However, one challenge to psychologists – and probably the most crucial one – is that most researchers may not have the necessary programming and computational skills to analyze big data. In this study we argue that psychologists can also conduct big data research and that, rather than trying to acquire new programming and computational skills, they should focus on their strengths, such as performing psychometric analyses and testing theories using multivariate analyses to explain phenomena. We propose a split/analyze/meta-analyze approach that allows psychologists to easily analyze big data. Two real datasets are used to demonstrate the proposed procedures in R. A new research agenda related to the analysis of big data in psychology is outlined at the end of the study.

  1. Aluminum, parathyroid hormone, and osteomalacia

    Energy Technology Data Exchange (ETDEWEB)

    Burnatowska-Hledin, M.A.; Kaiser, L.; Mayor, G.H.

    1983-01-01

    Aluminum exposure in man is unavoidable. The occurrence of dialysis dementia, vitamin D-resistant osteomalacia, and hypochromic microcytic anemia in dialysis patients underscores the potential for aluminum toxicity. Although exposure via dialysate and hyperalimentation leads to significant tissue aluminum accumulation, the ubiquitous occurrence of aluminum and the severe pathology associated with large aluminum burdens suggest that smaller exposures via the gastrointestinal tract and lungs could represent an important, though largely unrecognized, public health problem. It is clear that some aluminum absorption occurs with the ingestion of small amounts of aluminum in the diet and medicines, and even greater aluminum absorption is seen in individuals consuming large amounts of aluminum present in antacids. Aluminum absorption is enhanced in the presence of elevated circulating parathyroid hormone. In addition, elevated PTH leads to the preferential deposition of aluminum in brain and bone. Consequently, PTH is likely to be involved in the pathogenesis of toxicities in those organs. PTH excess also seems to lead to the deposition of aluminum in the parathyroid gland. The in vitro demonstration that aluminum inhibits parathyroid hormone release is consistent with the findings of a euparathyroid state in dialysis patients with aluminum related vitamin D-resistant osteomalacia. Nevertheless, it seems likely that hyperparathyroidism is at least initially involved in the pathogenesis of aluminum neurotoxicity and osteomalacia; the increases in tissue aluminum stores are followed by suppression of parathyroid hormone release, which is required for the evolution of osteomalacia. Impaired renal function is not a prerequisite for increased tissue aluminum burdens, nor for aluminum-related organ toxicity. Consequently, it is likely that these diseases will be observed in populations other than those with chronic renal disease.

  2. Human growth hormone (HGH), ch. 6

    International Nuclear Information System (INIS)

    A radioimmunoassay method for the human growth hormone (HGH) is described. The requirements are discussed in detail and a scheme for the preparation of incubation mixtures is given. HGH is labelled with 125I by the chloramine T method and purified by gel filtration or electrophoresis. Separation of bound and free-labelled hormones is performed by absorption of the free hormone, using talc or charcoal

  3. Hormones and aggression in childhood and adolescence

    OpenAIRE

    Ramirez, J. Martin

    2003-01-01

    This review is a survey on recent psychobiosocial studies on association between hormones and aggression/violence in children and adolescents, with a special focus on puberty, given the rapid changes in both hormones and behavior occurring during that developmental period. Since it cannot be assumed that all readers have much background knowledge, it inevitably begins with some comments about the concept and multifaceted nature of aggression, as well as with a brief reminding about hormone ca...

  4. Plant Hormones: Metabolism, Signaling and Crosstalk

    Institute of Scientific and Technical Information of China (English)

    Li-Jia Qu; Yunde Zhao

    2011-01-01

    @@ Plants synthesize various hormones in response to environmental cues and developmental signals to ensure their proper growth and development.Elucidation of the molecular mechanisms by which plant hormones control growth and development contributes to our understanding of fundamental plant biology and provides tools to improve crops.Because of their critical roles in plant growth and development, plant hormones have been studied extensively since the early days of plant biology.

  5. Monitoring Plant Hormones During Stress Responses

    OpenAIRE

    Engelberth, Marie J.; Engelberth, Jurgen

    2009-01-01

    Plant hormones and related signaling compounds play an important role in the regulation of plant responses to various environmental stimuli and stresses. Among the most severe stresses are insect herbivory, pathogen infection, and drought stress. For each of these stresses a specific set of hormones and/or combinations thereof are known to fine-tune the responses, thereby ensuring the plant's survival. The major hormones involved in the regulation of these responses are jasmonic acid (JA), sa...

  6. Gastric emptying, glucose metabolism and gut hormones

    DEFF Research Database (Denmark)

    Vermeulen, Mechteld A R; Richir, Milan C; Garretsen, Martijn K;

    2011-01-01

    To study the gastric-emptying rate and gut hormonal response of two carbohydrate-rich beverages. A specifically designed carbohydrate-rich beverage is currently used to support the surgical patient metabolically. Fruit-based beverages may also promote recovery, due to natural antioxidant...... and carbohydrate content. However, gastric emptying of fluids is influenced by its nutrient composition; hence, safety of preoperative carbohydrate loading should be confirmed. Because gut hormones link carbohydrate metabolism and gastric emptying, hormonal responses were studied....

  7. Pharmacologic development of male hormonal contraceptive agents.

    Science.gov (United States)

    Roth, M Y; Amory, J K

    2011-01-01

    The world population continues to increase dramatically despite the existence of contraceptive technology. The use of male hormonal contraception may help in preventing un intended pregnancies and managing future population growth. Male hormonal contraception relies on the administration of exogenous hormones to suppress spermatogenesis. Clinical trials have tested several regimens using testosterone, alone or in combination with a progestin. These regimens were shown to be >90% effective in preventing conception and were not associated with serious adverse events.

  8. Growth hormone and its disorders.

    Science.gov (United States)

    Ayuk, J; Sheppard, M C

    2006-01-01

    Growth hormone (GH) is synthesised and secreted by the somatotroph cells of the anterior lobe of the pituitary gland. Its actions involve multiple organs and systems, affecting postnatal longitudinal growth as well as protein, lipid, and carbohydrate metabolism. GH hypersecretion results in gigantism or acromegaly, a condition associated with significant morbidity and mortality, while GH deficiency results in growth retardation in children and the GH deficiency syndrome in adults. This article, aimed at non-paediatric physicians, examines the clinical features, diagnosis, and current concepts in the management of these conditions. PMID:16397076

  9. [Laboratory diagnosis of growth hormone].

    Science.gov (United States)

    Macchia, V; Mariano, A

    1993-09-01

    The role of Clinical Pathology Laboratory in normal and altered growth hormone secretion is discussed. In particular, it is reported that the normal GH secretion can be studied by serum and urine GH determinations whereas the diagnosis of GH deficiency rests upon the demonstration of an inadequate rise serum GH after provocative stimuli and serum measurement of somatomedins (IGF-I) by radioimmunoassay method. As it concerns increase GH secretion the diagnosis is clinically made (acromegaly and gigantism) and the laboratory has only the role to confirm it by the assessment of basal and stimulated GH secretion. PMID:7910655

  10. Hormonal contraceptives and venous thrombosis

    OpenAIRE

    Stegeman, Berendina Hendrika (Bernardine)

    2013-01-01

    Oral contraceptive use is associated with venous thrombosis. However, the mechanism behind this remains unclear. The aim of this thesis was to evaluate genetic variation in the first-pass metabolism of contraceptives, to identify the clinical implications of hormonal contraceptive use after a thrombotic event and to provide an overview of the risk of venous thrombosis per combined oral contraceptive. We found that the UGT2B7 gene in the first-pass metabolism may at least in part explain the r...

  11. Leptin and Hormones: Energy Homeostasis.

    Science.gov (United States)

    Triantafyllou, Georgios A; Paschou, Stavroula A; Mantzoros, Christos S

    2016-09-01

    Leptin, a 167 amino acid adipokine, plays a major role in human energy homeostasis. Its actions are mediated through binding to leptin receptor and activating JAK-STAT3 signal transduction pathway. It is expressed mainly in adipocytes, and its circulating levels reflect the body's energy stores in adipose tissue. Recombinant methionyl human leptin has been FDA approved for patients with generalized non-HIV lipodystrophy and for compassionate use in subjects with congenital leptin deficiency. The purpose of this review is to outline the role of leptin in energy homeostasis, as well as its interaction with other hormones. PMID:27519135

  12. Predicting the Probability of Abnormal Stimulated Growth Hormone Response in Children After Radiotherapy for Brain Tumors

    Energy Technology Data Exchange (ETDEWEB)

    Hua Chiaho, E-mail: Chia-Ho.Hua@stjude.org [Department of Radiological Sciences, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Wu Shengjie [Department of Biostatistics, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Chemaitilly, Wassim [Division of Endocrinology, Department of Pediatric Medicine, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States); Lukose, Renin C.; Merchant, Thomas E. [Department of Radiological Sciences, St. Jude Children' s Research Hospital, Memphis, Tennessee (United States)

    2012-11-15

    Purpose: To develop a mathematical model utilizing more readily available measures than stimulation tests that identifies brain tumor survivors with high likelihood of abnormal growth hormone secretion after radiotherapy (RT), to avoid late recognition and a consequent delay in growth hormone replacement therapy. Methods and Materials: We analyzed 191 prospectively collected post-RT evaluations of peak growth hormone level (arginine tolerance/levodopa stimulation test), serum insulin-like growth factor 1 (IGF-1), IGF-binding protein 3, height, weight, growth velocity, and body mass index in 106 children and adolescents treated for ependymoma (n = 72), low-grade glioma (n = 28) or craniopharyngioma (n = 6), who had normal growth hormone levels before RT. Normal level in this study was defined as the peak growth hormone response to the stimulation test {>=}7 ng/mL. Results: Independent predictor variables identified by multivariate logistic regression with high statistical significance (p < 0.0001) included IGF-1 z score, weight z score, and hypothalamic dose. The developed predictive model demonstrated a strong discriminatory power with an area under the receiver operating characteristic curve of 0.883. At a potential cutoff point of probability of 0.3 the sensitivity was 80% and specificity 78%. Conclusions: Without unpleasant and expensive frequent stimulation tests, our model provides a quantitative approach to closely follow the growth hormone secretory capacity of brain tumor survivors. It allows identification of high-risk children for subsequent confirmatory tests and in-depth workup for diagnosis of growth hormone deficiency.

  13. Steroid hormone runoff from agricultural test plots applied with municipal biosolids

    Science.gov (United States)

    Yang, Yun-Ya; Gray, James L.; Furlong, Edward T.; Davis, Jessica G.; ReVollo, Rhiannon C.; Borch, Thomas

    2012-01-01

    The potential presence of steroid hormones in runoff from sites where biosolids have been used as agricultural fertilizers is an environmental concern. A study was conducted to assess the potential for runoff of seventeen different hormones and two sterols, including androgens, estrogens, and progestogens from agricultural test plots. The field containing the test plots had been applied with biosolids for the first time immediately prior to this study. Target compounds were isolated by solid-phase extraction (water samples) and pressurized solvent extraction (solid samples), derivatized, and analyzed by gas chromatography–tandem mass spectrometry. Runoff samples collected prior to biosolids application had low concentrations of two hormones (estrone -1 and androstenedione -1) and cholesterol (22.5 ± 3.8 μg L-1). In contrast, significantly higher concentrations of multiple estrogens (-1), androgens (-1), and progesterone (-1) were observed in runoff samples taken 1, 8, and 35 days after biosolids application. A significant positive correlation was observed between antecedent rainfall amount and hormone mass loads (runoff). Hormones in runoff were primarily present in the dissolved phase (hormones from biosolids-amended agricultural fields, directly to surface waters or redistributed to terrestrial sites away from the point of application via runoff. Although concentrations decrease over time, 35 days is insufficient for complete degradation of hormones in soil at this site.

  14. Gender-specific regulation of response to thyroid hormone in aging

    Directory of Open Access Journals (Sweden)

    Suzuki Satoru

    2012-01-01

    Full Text Available Abstract Background Similar to other systems, the endocrine system is affected by aging. Thyroid hormone, the action of which is affected by many factors, has been shown to be associated with longevity. The most useful marker for the assessment of thyroid hormone action is TSH level. Although age and gender are believed to modify the pituitary set point or response to free thyroid hormone concentration, the precise age- and gender-dependent responses to thyroid hormone have yet to be reported. Methods We analyzed the results of 3564 thyroid function tests obtained from patients who received medication at both out- and inpatient clinics of Shinshu University Hospital. Subjects were from among those with thyroid function test results in the normal or mildly abnormal range. Based on a log-linear relationship between the concentrations of FHs and TSH, we established the putative resistance index to assess the relation between serum FH and TSH levels. Results Free thyroid hormone and TSH concentration showed an inverse log-linear relation. In males, there was a negative relationship between the free T3 resistance index and age. In females, although there were no relationships between age and FHs, the indices were positively related to age. Conclusions These findings indicated that there is a gender-specific response to thyroid hormone with aging. Although the TSH level is a useful marker for the assessment of peripheral thyroid hormone action, the values should be interpreted carefully, especially with regard to age- and gender-related differences.

  15. Pituitary hormone circadian rhythm alterations in cirrhosis patients with subclinical hepatic encephalopathy

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    AIM: To analyze pituitary hormone and melatonin cir- cadian rhythms, and to correlate hormonal alterations with clinical performance, hepatic disease severity and diagnostic tests used for the detection of hepatic en- cephalopathy in cirrhosis. METHODS: Twenty-six patients with cirrhosis were enrolled in the study. Thirteen patients hospitalized for systemic diseases not affecting the liver were included as controls. Liver disease severity was assessed by the Child-Pugh score. All patients underwent detailed neurological assessment, electroencephalogram (EEG), brain magnetic resonance imaging (MRI), assays of pi- tuitary hormone, cortisol and melatonin, and complete blood chemistry evaluation. RESULTS: Pituitary hormone and melatonin circadian patterns were altered in cirrhosis patients without clinical encephalopathy. Circadian hormone alterations were different in cirrhosis patients compared with con- trois. Although cortisol secretion was not altered in any patient with cirrhosis, the basal cortisol levels were low and correlated with EEG and brain MRI abnormalities. Melatonin was the only hormone associated with the severity of liver insufficiency. CONCLUSION: Abnormal pituitary hormone and mel- atonin circadian patterns are present in cirrhosis before the development of hepatic encephalopathy. These abnormalities may be early indicators of impending hepatic encephalopathy. Factors affecting the human biologic clock at the early stages of liver insufficiency require further study.

  16. The Aqueduct Global Flood Analyzer

    Science.gov (United States)

    Iceland, Charles

    2015-04-01

    As population growth and economic growth take place, and as climate change accelerates, many regions across the globe are finding themselves increasingly vulnerable to flooding. A recent OECD study of the exposure of the world's large port cities to coastal flooding found that 40 million people were exposed to a 1 in 100 year coastal flood event in 2005, and the total value of exposed assets was about US 3,000 billion, or 5% of global GDP. By the 2070s, those numbers were estimated to increase to 150 million people and US 35,000 billion, or roughly 9% of projected global GDP. Impoverished people in developing countries are particularly at risk because they often live in flood-prone areas and lack the resources to respond. WRI and its Dutch partners - Deltares, IVM-VU University Amsterdam, Utrecht University, and PBL Netherlands Environmental Assessment Agency - are in the initial stages of developing a robust set of river flood and coastal storm surge risk measures that show the extent of flooding under a variety of scenarios (both current and future), together with the projected human and economic impacts of these flood scenarios. These flood risk data and information will be accessible via an online, easy-to-use Aqueduct Global Flood Analyzer. We will also investigate the viability, benefits, and costs of a wide array of flood risk reduction measures that could be implemented in a variety of geographic and socio-economic settings. Together, the activities we propose have the potential for saving hundreds of thousands of lives and strengthening the resiliency and security of many millions more, especially those who are most vulnerable. Mr. Iceland will present Version 1.0 of the Aqueduct Global Flood Analyzer and provide a preview of additional elements of the Analyzer to be released in the coming years.

  17. Fuel analyzer; Analisador de combustiveis

    Energy Technology Data Exchange (ETDEWEB)

    Cozzolino, Roberval [RS Motors, Indaiatuba, SP (Brazil)

    2008-07-01

    The current technology 'COMBUSTIMETRO' aims to examine the fuel through performance of the engine, as the role of the fuel is to produce energy for the combustion engine in the form of which is directly proportional to the quality and type of fuel. The 'COMBUSTIMETRO' has an engine that always keeps the same entry of air, fuel and fixed point of ignition. His operation is monitored by sensors (Sonda Lambda, RPM and Gases Analyzer) connected to a processor that performs calculations and records the information, generate reports and graphs. (author)

  18. [Examination of the olfactory analyzer].

    Science.gov (United States)

    Domrachev, A A; Afon'kin, V Iu

    2002-01-01

    A method of threshold olfactometry is proposed consisting in the use of three olfactive substances (tincture of valerian, acetic acid, liquid ammonia) in selected concentrations. This allows to investigate the thresholds of certain modality. Each concentration of the olfactive substance is placed into a glass bottle (100 ml) and stored at the temperature 18-20 degrees C. The examination of the state of the olfactory analyzer within a 24-h working day showed stability of threshold olfactometry when the organism is tired. Utilization of threshold olfactometry in some diagnostic areas is shown. PMID:12056163

  19. Antimüllerian hormone in gonadotropin releasing-hormone antagonist cycles

    DEFF Research Database (Denmark)

    Arce, Joan-Carles; La Marca, Antonio; Mirner Klein, Bjarke;

    2013-01-01

    To assess the relationships between serum antimüllerian hormone (AMH) and ovarian response and treatment outcomes in good-prognosis patients undergoing controlled ovarian stimulation using a gonadotropin-releasing hormone (GnRH) antagonist protocol.......To assess the relationships between serum antimüllerian hormone (AMH) and ovarian response and treatment outcomes in good-prognosis patients undergoing controlled ovarian stimulation using a gonadotropin-releasing hormone (GnRH) antagonist protocol....

  20. Anomalies in the hormonal status of athymic nude mice.

    Science.gov (United States)

    Köpf-Maier, P; Mboneko, V F

    1990-01-01

    The serum levels of hormones that are known to influence growth, development, and differentiation of the skin and its appendages were analyzed in female haired (NMRI) and nude (NMRI, nu/nu) mice. Whereas the concentrations of testosterone, prolactin, and triiodothyronine did not differ in nude animals from those found in normal mice of the same age in the anestrous phase of the sexual cycle, the serum levels of estradiol, progesterone, and thyroxine were found in female nude mice at significantly lower levels than in normally haired animals. These results point to a hormonal situation that contributes to the poor fertility of homozygous (nu/nu) female mice and may promote impairment of growth and differentiation of skin and hair, resulting in the macroscopic nudity of athymic, nude mice. PMID:2370246