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Sample records for reducing perfusion pressure

  1. Sodium addition and/or oxygen saturation of iohexol during normal and reduced perfusion pressure

    International Nuclear Information System (INIS)

    Baath, L.

    1990-01-01

    The influence on contractile force (CF) and the propensity for ventricular fibrillation (VF) from infusing the non-ionic contrast medium iohexol during normal (75 cm H 2 O) and reduced perfusion pressure (35 cm H 2 O) were investigated in the isolated rabbit heart. Both during normal and reduced perfusion pressure iohexol (150 mg I/ml) with oxygen saturation caused a smaller reduction of CF than iohexol without oxygen. During reduced pressure iohexol with sodium addition (28 mM NaCl) caused less depression of CF than iohexol without sodium. The combination of sodium addition and oxygen saturation had the least influence on CF. Iohexol (350 mg I/ml) without sodium had a similar fibrillatory propensity during both normal and reduced pressure. Enriching iohexol with 28 mM NaCl decreased the risk of VF. The decrease was similar during both normal and reduced pressure. The risk of VF from oxygen saturation of iohexol (350 mg I/ml, without sodium) was similar during both normal and reduced pressure. It is concluded that a small addition of sodium and/or oxygen saturation of a non-ionic monomeric contrast medium have beneficial effects on the heart both during normal perfusion pressure and during ischemia. (orig.)

  2. Low pulmonary artery flush perfusion pressure combined with high positive end-expiratory pressure reduces oedema formation in isolated porcine lungs

    International Nuclear Information System (INIS)

    Schumann, Stefan; Schließmann, Stephan J; Wagner, Giskard; Goebel, Ulrich; Priebe, Hans-Joachim; Guttmann, Josef; Kirschbaum, Andreas

    2010-01-01

    Flush perfusion of the pulmonary artery with organ protection solution is a standard procedure before lung explantation. However, rapid flush perfusion may cause pulmonary oedema which is deleterious in the lung transplantation setting. In this study we tested the hypotheses that high pulmonary perfusion pressure contributes to the development of pulmonary oedema and positive end-expiratory pressure (PEEP) counteracts oedema formation. We expected oedema formation to increase weight and decrease compliance of the lungs on the basis of a decrease in alveolar volume as fluid replaces alveolar air spaces. The pulmonary artery of 28 isolated porcine lungs was perfused with a low-potassium dextrane solution at low (mean 27 mmHg) or high (mean 40 mmHg) pulmonary artery pressure (PAP) during mechanical ventilation at low (4 cmH 2 O) or high (8 cmH 2 O) PEEP, respectively. Following perfusion and storage, relative increases in lung weight were smaller (p < 0.05) during perfusion at low PAP (62 ± 32% and 42 ± 26%, respectively) compared to perfusion at high PAP (133 ± 54% and 87 ± 30%, respectively). Compared to all other PAP–PEEP combinations, increases in lung weight were smallest (44 ± 9% and 27 ± 12%, respectively), nonlinear intratidal lung compliance was largest (46% and 17% respectively, both p < 0.05) and lung histology showed least infiltration of mononuclear cells in the alveolar septa, and least alveolar destruction during the combination of low perfusion pressure and high PEEP. The findings suggest that oedema formation during pulmonary artery flush perfusion in isolated and ventilated lungs can be reduced by choosing low perfusion pressure and high PEEP. PAP–PEEP titration to minimize pulmonary oedema should be based on lung mechanics and PAP monitoring

  3. Molecular hydrogen ameliorates several characteristics of preeclampsia in the Reduced Uterine Perfusion Pressure (RUPP) rat model.

    Science.gov (United States)

    Ushida, Takafumi; Kotani, Tomomi; Tsuda, Hiroyuki; Imai, Kenji; Nakano, Tomoko; Hirako, Shima; Ito, Yumiko; Li, Hua; Mano, Yukio; Wang, Jingwen; Miki, Rika; Yamamoto, Eiko; Iwase, Akira; Bando, Yasuko K; Hirayama, Masaaki; Ohno, Kinji; Toyokuni, Shinya; Kikkawa, Fumitaka

    2016-12-01

    Oxidative stress plays an important role in the pathogenesis of preeclampsia. Recently, molecular hydrogen (H 2 ) has been shown to have therapeutic potential in various oxidative stress-related diseases. The aim of this study is to investigate the effect of H 2 on preeclampsia. We used the reduced utero-placental perfusion pressure (RUPP) rat model, which has been widely used as a model of preeclampsia. H 2 water (HW) was administered orally ad libitum in RUPP rats from gestational day (GD) 12-19, starting 2 days before RUPP procedure. On GD19, mean arterial pressure (MAP) was measured, and samples were collected. Maternal administration of HW significantly decreased MAP, and increased fetal and placental weight in RUPP rats. The increased levels of soluble fms-like tyrosine kinase-1 (sFlt-1) and diacron reactive oxygen metabolites as a biomarker of reactive oxygen species in maternal blood were decreased by HW administration. However, vascular endothelial growth factor level in maternal blood was increased by HW administration. Proteinuria, and histological findings in kidney were improved by HW administration. In addition, the effects of H 2 on placental villi were examined by using a trophoblast cell line (BeWo) and villous explants from the placental tissue of women with or without preeclampsia. H 2 significantly attenuated hydrogen peroxide-induced sFlt-1 expression, but could not reduce the expression induced by hypoxia in BeWo cells. H 2 significantly attenuated sFlt-1 expression in villous explants from women with preeclampsia, but not affected them from normotensive pregnancy. The prophylactic administration of H 2 attenuated placental ischemia-induced hypertension, angiogenic imbalance, and oxidative stress. These results support the theory that H 2 has a potential benefit in the prevention of preeclampsia. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Plasma-mediated vascular dysfunction in the reduced uterine perfusion pressure model of preeclampsia: a microvascular characterization.

    LENUS (Irish Health Repository)

    Walsh, Sarah K

    2012-01-31

    Preeclampsia is associated with widespread maternal vascular dysfunction, which is thought to be mediated by circulating factor(s). The aim of the study was to characterize vascular function in the reduced uterine perfusion pressure (RUPP) rat model of preeclampsia and to investigate the role of plasma factors in mediating any observed changes in vascular reactivity. Mean arterial blood pressure and vascular function were measured in RUPP and control rats. Mesenteric vessels from both virgin and pregnant rats were exposed for 1 hour or overnight to plasma from both RUPP and control rats and their vascular function assessed. RUPP rats were characterized by severe hypertension, restricted fetal growth, and reduced placental weight (P<0.001). Vasorelaxation was impaired in resistance vessels from RUPP compared with control rats (acetylcholine: R(max) 70+\\/-3 versus 92+\\/-1 [NP] and 93+\\/-3% [sham], P<0.01; bradykinin: 40+\\/-2 versus 62+\\/-2 [NP] and 59+\\/-4% [sham], P<0.001). Incubation of vessels from pregnant (but not virgin) animals with RUPP plasma overnight resulted in an attenuation of vasorelaxant responses (acetylcholine: 63+\\/-7 versus 86+\\/-2%, P<0.05; bradykinin: 35+\\/-5 versus 55+\\/-6%, P<0.001). The residual relaxant response in RUPP plasma-treated vessels was not further attenuated after treatment with N(omega)-nitro-l-arginine methyl ester (acetylcholine: 57+\\/-7 versus 63+\\/-7%, ns; bradykinin: 37+\\/-5 versus 35+\\/-5%, ns). The RUPP rat model is characterized by an impaired response to vasodilators which may be attributable to one or more circulating factors. This plasma-mediated endothelial dysfunction appears to be a pregnancy-dependent effect. Furthermore, nitric oxide-mediated vasorelaxation appears to be absent in RUPP plasma-treated vessels.

  5. Influence of ocular perfusion pressure fluctuation on glaucoma

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    Min-Zi Ren

    2015-12-01

    Full Text Available AIM:To investigate the influence of ocular perfusion pressure fluctuation on glaucoma. METHODS:Forty patients with primary open angle glaucoma from January 2013 to June 2015 in our hospital were used as observation group and 40 families were used as control group. Circadian fluctuation of intraocular pressure, blood pressure and ocular perfusion pressure in 24h were determined to obtain systolic ocular perfusion pressure(SOPP, diastolic ocular perfusion pressure(DOPPand mean ocular perfusion pressure(MOPP. Pearson linear correlation was used to analyze the correlation of circadian MOPP fluctuation with cup-disc ratio, mean defect(MDand the picture standard deviation(PSD. RESULTS:The fluctuation of MOPP, SOPP and DOPP of observation group were significantly higher than those of control group(Pr=-0.389, 95%CI:-0.612~-0.082; P=0.011, was positively correlated with PSD(r=0.512, 95%CI:0.139 ~0.782; P=0.008; no correlation was found between it and the vertical cup-disc ratio(r=0.115, 95%CI:0.056~0.369; P=0.355. CONCLUSION:Ocular perfusion pressure fluctuations in patients with primary open angle glaucoma may reflect the severity of the disease and may make the situation aggravating. Therefore through perfusion pressure monitor in 24h may help us understand the ocular blood flow and the development of primary open-angle glaucoma.

  6. Hypothermic Machine Perfusion of Kidney Grafts: Which Pressure is Preferred?

    NARCIS (Netherlands)

    Doorschodt, B. M.; Schreinemachers, M. C. J. M.; Behbahani, M.; Florquin, S.; Weis, J.; Staat, M.; Tolba, R. H.

    2011-01-01

    To assess the effect of the perfusion pressure (PP) during machine perfusion (MP) on the preservation quality of kidney grafts, we compared mean PPs of 25 and 30 mmHg using a porcine autotransplantation model. After assessment of the microcirculation, animals underwent left nephrectomy. Thereafter,

  7. Carotid artery disease and low cerebral perfusion pressure

    DEFF Research Database (Denmark)

    Schroeder, T; Utzon, N P; Aabech, J

    1990-01-01

    Direct internal carotid artery blood pressure measurements in patients undergoing carotid endarterectomy identified 49 patients, among 239 consecutive cases (21%), who had a reduction in perfusion pressure of 20% or more. The clinical history, objective findings and angiographic data were compared...

  8. Perfusion of veins at arterial pressure increases the expression of KLF5 and cell cycle genes in smooth muscle cells

    International Nuclear Information System (INIS)

    Amirak, Emre; Zakkar, Mustafa; Evans, Paul C.; Kemp, Paul R.

    2010-01-01

    Vascular smooth muscle cell (VSMC) proliferation remains a major cause of veno-arterial graft failure. We hypothesised that exposure of venous SMCs to arterial pressure would increase KLF5 expression and that of cell cycle genes. Porcine jugular veins were perfused at arterial or venous pressure in the absence of growth factors. The KLF5, c-myc, cyclin-D and cyclin-E expression were elevated within 24 h of perfusion at arterial pressure but not at venous pressure. Arterial pressure also reduced the decline in SM-myosin heavy chain expression. These data suggest a role for KLF5 in initiating venous SMCs proliferation in response to arterial pressure.

  9. Endotoxemia reduces cerebral perfusion but enhances dynamic cerebrovascular autoregulation at reduced arterial carbon dioxide tension*

    DEFF Research Database (Denmark)

    Brassard, Patrice; Kim, Yu-Sok; van Lieshout, Johannes

    2012-01-01

    OBJECTIVE:: The administration of endotoxin to healthy humans reduces cerebral blood flow but its influence on dynamic cerebral autoregulation remains unknown. We considered that a reduction in arterial carbon dioxide tension would attenuate cerebral perfusion and improve dynamic cerebral autoreg...

  10. Continuous determination of optimal cerebral perfusion pressure in traumatic brain injury

    NARCIS (Netherlands)

    Aries, M.J.H.; Czosnyka, Marek; Budohoski, Karol P.; Steiner, Luzius A.; Lavinio, Andrea; Kolias, Angelos G.; Hutchinson, Peter J.; Brady, Ken M.; Menon, David K.; Pickard, John D.; Smielewski, Peter

    Objectives: We have sought to develop an automated methodology for the continuous updating of optimal cerebral perfusion pressure (CPPopt) for patients after severe traumatic head injury, using continuous monitoring of cerebrovascular pressure reactivity. We then validated the CPPopt algorithm by

  11. Tissue perfusion as a key underlying concept of pressure ulcer development and treatment.

    Science.gov (United States)

    Wywialowski, E F

    1999-03-01

    The purpose of this article is to refine and advance the theory that tissue perfusion is the key concept in the development and delayed healing of pressure ulcers. The person likely to have (be at risk for) pressure ulcers is at greater risk for inadequate tissue perfusion generally and specifically at pressure points. Accordingly, the tissue perfusion theory of pressure ulcer development states that the factors that contribute to inadequate tissue perfusion should be used to predict (identify risk factors for) pressure ulcer development and delayed healing. Factors influencing a person's adequacy of tissue perfusion need to be assessed to identify risk for pressure ulcers. In addition, adequate tissue perfusion needs to be maintained to provide for healing of such wounds. Current beliefs about the causes and prevention of pressure ulcers are described. Physiologic components of the tissue perfusion theory are discussed: cellular exchange of nutrients and wastes, autoregulation of blood flow at the cellular level, and regulatory mechanisms that affect tissue perfusion when it is significantly compromised. The North American Nursing Diagnosis Association (NANDA) framework is used to classify or group examples of common pathophysiologic, treatment-related, situational, and maturational factors. Implications for research, practice, and education also are discussed.

  12. Reduced Perfusion in Broca’s Area in Developmental Stuttering

    Science.gov (United States)

    Desai, Jay; Huo, Yuankai; Wang, Zhishun; Bansal, Ravi; Williams, Steven C. R.; Lythgoe, David; Zelaya, Fernando O.; Peterson, Bradley S.

    2016-01-01

    Objective To study resting cerebral blood flow in children and adults with developmental stuttering. Methods We acquired pulsed arterial spin labeling magnetic resonance imaging data in 26 participants with stuttering and 36 healthy, fluent controls. While covarying for age, sex, and IQ, we compared perfusion values voxel-wise across diagnostic groups and assessed correlations of perfusion with stuttering severity within the stuttering group and with measures of motor speed in both groups. Results We detected lower regional Cerebral Blood Flow (rCBF) at rest in the stuttering group compared to healthy controls in Broca’s area bilaterally and the superior frontal gyrus. rCBF values in Broca’s area bilaterally correlated inversely with the severity of stuttering and extended posteriorly into other portions of the language loop. We also found increased rCBF in cerebellar nuclei and parietal cortex in the stuttering group compared to healthy controls. Findings were unchanged in child-only analyses and when excluding participants with comorbid illnesses or those taking medication. Conclusions rCBF is reduced in Broca’s region in persons who stutter. More severe stuttering is associated with even greater reductions in rCBF to Broca’s region, additive to the underlying putative trait reduction in rCBF relative to control values. Moreover, a greater abnormality in rCBF in the posterior language loop is associated with more severe symptoms, suggesting that a common pathophysiology throughout the language loop likely contributes to stuttering severity. PMID:28035724

  13. Effects of Constant Flow vs. Constant Pressure Perfusion on Fluid Filtration in Severe Hypothermic Isolated Blood-Perfused Rat Lungs.

    Science.gov (United States)

    Halsøy, Kathrine; Kondratiev, Timofey; Tveita, Torkjel; Bjertnaes, Lars J

    2016-01-01

    Victims of severe accidental hypothermia are prone to fluid extravasation but rarely develop lung edema. We hypothesize that combined hypothermia-induced increase in pulmonary vascular resistance (PVR) and a concomitant fall in cardiac output protect the lungs against edema development. Our aim was to explore in hypothermic-isolated blood-perfused rat lungs whether perfusion at constant pressure influences fluid filtration differently from perfusion at constant flow. Isolated blood-perfused rat lungs were hanging freely in a weight transducer for measuring weight changes (ΔW). Fluid filtration coefficient (Kfc), was determined by transiently elevating left atrial pressure (Pla) by 5.8 mmHg two times each during normothermia (37°C) and during hypothermia (15°C). The lung preparations were randomized to two groups. One group was perfused with constant flow (Constant flow group) and the other group with constant pulmonary artery pressure (Constant PPA group). Microvascular pressure (Pmv) was determined before and during elevation of Pla (ΔPmv) by means of the double occlusion technique. Kfc was calculated with the formula Kfc = ΔW/ΔPmv/min. All Kfc values were normalized to predicted lung weight (P LW ), which was based on body weight (BW) according to the formula: P LW  = 0.0053 BW - 0.48 and presented as Kfc PLW in mg/min/mmHg/g. At cessation, bronchoalveolar lavage (BAL) fluid/perfusate protein concentration (B/P) ratio was determined photometrically. Data were analyzed with parametric or non-parametric tests as appropriate. p  Kfc PLW and B/P ratio increased significantly by more than 10-fold during hypothermia concerted by visible signs of edema in the trachea. Hemoglobin and hematocrit increased within the Constant flow group and between the groups at cessation of the experiments. In hypothermic rat lungs perfused at constant flow, fluid filtration coefficient per gram P LW and B/P ratio increased more than 10-fold concerted by increased

  14. The "Skull Flap" a new conceived device for decompressive craniectomy experimental study on dogs to evaluate the safety and efficacy in reducing intracranial pressure and subsequent impact on brain perfusion.

    Science.gov (United States)

    Salvatore, Chibbaro; Fabrice, Vallee; Marco, Marsella; Leonardo, Tigan; Thomas, Lilin; Benoit, Lecuelle; Bernard, George; Pierre, Kehrli; Eric, Vicaut; Paolo, Diemidio

    2013-10-01

    Decompressive craniectomy (DC) is a procedure performed increasingly often in current neurosurgical practice. Significant perioperative morbidity may be associated to this procedure because of the large skull defect; also, later closure of the skull defect (cranioplasty) may be associated to post-operative morbidity as much as any other reconstructive operation. The authors present a newly conceived/developed device: The "Skull Flap" (SF). This system, placed at the time of the craniectomy, offers the possibility to provide cranial reconstruction sparing patients a second operation. In other words, DC and cranioplasty essentially take place at the same time and in addition, patients retain their own bone flap. The current study conducted on animal models, represents the logical continuation of a prior recent study, realized on cadaver specimens, to assess the efficacy and safety of this recently developed device. This is an experimental pilot study on dogs to assess both safety and efficacy of the SF device. Two groups of experimental raised intracranial pressure animal models underwent DC; in the first group of dogs, the bone flap was left in raised position above the skull defect using the SF device; on the second group the flap was discarded. All dogs underwent transcranial Doppler (TCD) to assess brain perfusion. Head computed tomography (CT) scan to determine flap position was also obtained in the group in which the SF device was placed. SF has proved to be a strong fixation device that allows satisfactory brain decompression by keeping the bone flap elevated from the swollen brain; later on, the SF allows cranial reconstruction in a simple way without requiring a second staged operation. In addition, it is relevant to note that brain perfusion was measured and found to be better in the group receiving the SF (while the flap being in a raised as well as in its natural position) comparing to the other group. The SF device has proved to be very easy to place

  15. The "Skull Flap" a new conceived device for decompressive craniectomy experimental study on dogs to evaluate the safety and efficacy in reducing intracranial pressure and subsequent impact on brain perfusion

    Directory of Open Access Journals (Sweden)

    Chibbaro Salvatore

    2013-01-01

    Full Text Available Background: Decompressive craniectomy (DC is a procedure performed increasingly often in current neurosurgical practice. Significant perioperative morbidity may be associated to this procedure because of the large skull defect; also, later closure of the skull defect (cranioplasty may be associated to post-operative morbidity as much as any other reconstructive operation. The authors present a newly conceived/developed device: The "Skull Flap" (SF. This system, placed at the time of the craniectomy, offers the possibility to provide cranial reconstruction sparing patients a second operation. In other words, DC and cranioplasty essentially take place at the same time and in addition, patients retain their own bone flap. The current study conducted on animal models, represents the logical continuation of a prior recent study, realized on cadaver specimens, to assess the efficacy and safety of this recently developed device. Materials and Methods: This is an experimental pilot study on dogs to assess both safety and efficacy of the SF device. Two groups of experimental raised intracranial pressure animal models underwent DC; in the first group of dogs, the bone flap was left in raised position above the skull defect using the SF device; on the second group the flap was discarded. All dogs underwent transcranial Doppler (TCD to assess brain perfusion. Head computed tomography (CT scan to determine flap position was also obtained in the group in which the SF device was placed. Results: SF has proved to be a strong fixation device that allows satisfactory brain decompression by keeping the bone flap elevated from the swollen brain; later on, the SF allows cranial reconstruction in a simple way without requiring a second staged operation. In addition, it is relevant to note that brain perfusion was measured and found to be better in the group receiving the SF (while the flap being in a raised as well as in its natural position comparing to the other

  16. Reduced perfusion in Broca's area in developmental stuttering.

    Science.gov (United States)

    Desai, Jay; Huo, Yuankai; Wang, Zhishun; Bansal, Ravi; Williams, Steven C R; Lythgoe, David; Zelaya, Fernando O; Peterson, Bradley S

    2017-04-01

    To study resting cerebral blood flow in children and adults with developmental stuttering. We acquired pulsed arterial spin labeling magnetic resonance imaging data in 26 participants with stuttering and 36 healthy, fluent controls. While covarying for age, sex, and IQ, we compared perfusion values voxel-wise across diagnostic groups and assessed correlations of perfusion with stuttering severity within the stuttering group and with measures of motor speed in both groups. We detected lower regional Cerebral Blood Flow (rCBF) at rest in the stuttering group compared with healthy controls in Broca's area bilaterally and the superior frontal gyrus. rCBF values in Broca's area bilaterally correlated inversely with the severity of stuttering and extended posteriorly into other portions of the language loop. We also found increased rCBF in cerebellar nuclei and parietal cortex in the stuttering group compared with healthy controls. Findings were unchanged in child-only analyses and when excluding participants with comorbid illnesses or those taking medication. rCBF is reduced in Broca's region in persons who stutter. More severe stuttering is associated with even greater reductions in rCBF to Broca's region, additive to the underlying putative trait reduction in rCBF relative to control values. Moreover, a greater abnormality in rCBF in the posterior language loop is associated with more severe symptoms, suggesting that a common pathophysiology throughout the language loop likely contributes to stuttering severity. Hum Brain Mapp 38:1865-1874, 2017. © 2017 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  17. Skin Perfusion Pressure Is a Prognostic Factor in Hemodialysis Patients

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    Shingo Hatakeyama

    2012-01-01

    Full Text Available Peripheral arterial disease (PAD is common in hemodialysis patients and predicts a poor prognosis. We conducted a prospective cohort study to identify risk factors for PAD including skin perfusion pressure (SPP in hemodialysis patients. The cohort included 373 hemodialysis patients among 548 patients who received hemodialysis at Oyokyo Kidney Research Institute, Hirosaki, Japan from August 2008 to December 2010. The endpoints were lower limb survival (peripheral angioplasty or amputation events and overall survival of 2 years. Our results showed that <70 mmHg SPP was a poor prognosis for the lower limb survival and overall survival. We also identified age, history of cardiovascular disease, presence of diabetes mellitus, smoking history, and SPP < 70 mmHg as independent risk factors for lower limb survival and overall survival. Then, we constructed risk criteria using the significantly independent risk factors. We can clearly stratify lower limb survival and overall survival of the hemodialysis patients into 3 groups. Although the observation period is short, we conclude that SPP value has the potential to be a risk factor that predicts both lower limb survival and the prognosis of hemodialysis patients.

  18. A Short Period of Ventilation without Perfusion Seems to Reduce Atelectasis without Harming the Lungs during Ex Vivo Lung Perfusion

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    Sandra Lindstedt

    2013-01-01

    Full Text Available To evaluate the lung function of donors after circulatory deaths (DCDs, ex vivo lung perfusion (EVLP has been shown to be a valuable method. We present modified EVLP where lung atelectasis is removed, while the lung perfusion is temporarily shut down. Twelve pigs were randomized into two groups: modified EVLP and conventional EVLP. When the lungs had reached 37°C in the EVLP circuit, lung perfusion was temporarily shut down in the modified EVLP group, and positive end-expiratory pressure (PEEP was increased to 10 cm H2O for 10 minutes. In the conventional EVLP group, PEEP was increased to 10 cm H2O for 10 minutes with unchanged lung perfusion. In the modified EVLP group, the arterial oxygen partial pressure (PaO2 was 18.5 ± 7.0 kPa before and 64.5 ± 6.0 kPa after the maneuver (P<0.001. In the conventional EVLP group, the PaO2 was 16.8 ± 3.1 kPa and 46.8 ± 2.7 kPa after the maneuver (P<0.01; P<0.01. In the modified EVLP group, the pulmonary graft weight was unchanged, while in the conventional EVLP group, the pulmonary graft weight was significantly increased. Modified EVLP with normoventilation of the lungs without ongoing lung perfusion for 10 minutes may eliminate atelectasis almost completely without harming the lungs.

  19. Coronary oscillatory flow amplitude is more affected by perfusion pressure than ventricular pressure.

    Science.gov (United States)

    Krams, R; Sipkema, P; Westerhof, N

    1990-06-01

    In this study on the isolated, maximally vasodilated, blood-perfused cat heart we investigated the relation between left ventricular developed pressure (delta Piv) and coronary oscillatory flow amplitude (diastolic minus systolic flow, delta F) at different levels of constant perfusion pressure (Pp). We hypothesized that the effect of cardiac contraction on the phasic flow results from the changing elastic properties of cardiac muscle. The coronary vessel compartment can, as can the left ventricular lumen compartment, be described by a time-varying elastance. This concept predicts that the effect of left ventricular pressure on delta F is small, whereas the effect of Pp is considerable. Both the waterfall model and the intramyocardial pump model predict the inverse. The relation between delta Piv and delta F at a Pp of 10 kPa is delta F = (4.71 +/- 3.08).delta Piv + 337 +/- 75 (slope in ml.min-1.100 g-1.kPa-1 and intercept in ml.min-1.100 g-1; n = 7); the relation between (constant levels of) Pp and delta F at a constant delta Piv of 10 kPa is delta F = 51.Pp + 211 (slope in ml.min-1.100 g-1.kPa-1 and intercept in ml.min-1.100 g-1; n = 6). The differences in slope are best predicted by the time-varying elastance concept.

  20. A relative study of hepatic perfusion and portal vein pressure in rats with liver cirrhosis

    International Nuclear Information System (INIS)

    Li Jiaping; Yang Jianyong; Chen Wei; Huang Yonghui

    2006-01-01

    Objective: To evaluate spiral CT perfusion in assessing portal vein pressure in rats with different stages of liver cirrhosis. Methods Seventeen rats with early stage of liver cirrhosis, 18 with intermediate stage, 12 with advanced stage, and 13 healthy rats as a control group were selected and recieved hepatic perfusion on a single-row spiral CT scanner. The parameters of hepatic perfusion were calculated using the deconvolution method. The portal vein pressure was measured by multi-physiographer. Results: (1) In study group, the PVP (portal venous perfusion) and THBP (total hepatic blood perfusion) were negatively correlated with FPP, while positively correlated with the HPI (hepatic perfusion index) and MTT (mean transit time). The FPP had a close relation with PVP. The equation, Y 20.671-3.195X, could be conducted with linear regression analysis. (2) According to the linear regression equation mentioned above, the FPP in 47 rats were 16.090±2.150 cmH 2 0, which was highly correlated with the observed valuel6.108±3.662 cmH 2 O (r=0.823 P<0.01). Conclusion: CT perfusion is a new non-invasive and efficient modality for assessment of the portal pressure in liver cirrhosis in various stages. (authors)

  1. Spatial interaction between tissue pressure and skeletal muscle perfusion during contraction.

    Science.gov (United States)

    van Donkelaar, C C; Huyghe, J M; Vankan, W J; Drost, M R

    2001-05-01

    The vascular waterfall theory attributes decreased muscle perfusion during contraction to increased intramuscular pressure (P(IM)) and concomitant increase in venous resistance. Although P(IM) is distributed during contractions, this theory does not account for heterogeneity. This study hypothesises that pressure heterogeneity could affect the interaction between P(IM) rise and perfusion. Regional tissue perfusion during submaximum (100kPa) tetanic contraction is studied, using a finite element model of perfused contracting skeletal muscle. Capillary flow in muscles with one proximal artery and vein (SIM(1)) and with an additional distal artery and vein (SIM(2)) is compared. Blood flow and pressures at rest and P(IM) during contraction ( approximately 25kPa maximally) are similar between simulations, but capillary flow and venous pressure differ. In SIM(2), venous pressure and capillary flow correspond to P(IM) distribution, whereas capillary flow in SIM(1) is less than 10% of flow in SIM(2), in the muscle half without draining vein. This difference is caused by a high central P(IM), followed by central venous pressure rise, in agreement with the waterfall theory. The high central pressure (SIM(1)), obstructs outflow from the distal veins. Distal venous pressure rises until central blood pressure is reached, although local P(IM) is low. Adding a distal vein (SIM(2)) restores the perfusion. It is concluded that regional effects contribute to the interaction between P(IM) and perfusion during contraction. Unlike stated by the vascular waterfall theory, venous pressure may locally exceed P(IM). Although this can be explained by the principles of this theory, the theory does not include this phenomenon as such.

  2. Dynamic Susceptibility Contrast Perfusion Magnetic Resonance Imaging Demonstrates Reduced Periventricular Cerebral Blood Flow in Dogs with Ventriculomegaly

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    Martin J. Schmidt

    2017-08-01

    Full Text Available The nature of ventriculomegaly in dogs is still a matter of debate. Signs of increased intraventricular pressure and atrophy of the cerebral white matter have been found in dogs with ventriculomegaly, which would imply increased intraventricular pressure and, therefore, a pathological condition, i.e., to some extent. Reduced periventricular blood flow was found in people with high elevated intraventricular pressure. The aim of this study was to compare periventricular brain perfusion in dogs with and without ventriculomegaly using perfusion weighted-magnetic-resonance-imaging to clarify as to whether ventriculomegaly might be associated with an increase in intraventricular pressure. Perfusion was measured in 32 Cavalier King Charles spaniels (CKCS with ventriculomegaly, 10 CKCSs were examined as a control group. Cerebral blood flow (CBF was measured using free-hand regions of interest (ROI in five brain regions: periventricular white matter, caudate nucleus, parietal cortex, hippocampus, and thalamus. CBF was significantly lower in the periventricular white matter of the dogs with ventriculomegaly (p = 0.0029 but not in the other ROIs. Reduction of periventricular CBF might imply increase of intraventricular pressure in ventriculomegaly.

  3. Wound healing in below-knee amputations in relation to skin perfusion pressure

    DEFF Research Database (Denmark)

    Holstein, P; Sager, P; Lassen, N A

    1979-01-01

    In 60 below-knee amputations the healing of the stumps was correlated with the local skin perfusion pressure (SPP) measured preoperatively as the external pressure required to stop isotope washout using 131I- or 125I--antipyrine mixed with histamine. Of the eight cases with an SPP below 20 mm...

  4. Skin perfusion pressure as an indicator of tissue perfusion in valvular heart surgery: Preliminary results from a prospective, observational study.

    Directory of Open Access Journals (Sweden)

    Young Song

    Full Text Available Hemodynamic management aims to provide adequate tissue perfusion, which is often altered during cardiac surgery with cardiopulmonary bypass (CPB. We evaluated whether skin perfusion pressure (SPP can be used for monitoring of adequacy of tissue perfusion in patients undergoing valvular heart surgery. Seventy-two patients undergoing valve replacement were enrolled. SPP and serum lactate level were assessed after anaesthesia induction (baseline, during CPB, after CPB-off, end of surgery, arrival at intensive care unit, and postoperative 6 h. Lactate was further measured until postoperative 48 h. Association of SPP with lactate and 30-day morbidity comprising myocardial infarction, acute kidney injury, stroke, prolonged intubation, sternal infection, reoperation, and mortality was assessed. Among the lactate levels, postoperative 6 h peak value was most closely linked to composite of 30-day morbidity. The SPP value during CPB and its % change from the baseline value were significantly associated with the postoperative 6 h peak lactate (r = -0.26, P = 0.030 and r = 0.47, P = 0.001, respectively. Optimal cut-off of % decrease in SPP during CPB from baseline value for the postoperative 6 h hyperlactatemia was 48% (area under curve, 0.808; 95% confidence interval (CI, 0.652-0.963; P = 0.001. Decrease in SPP >48% during CPB from baseline value was associated with a 12.8-fold increased risk of composite endpoint of 30-day morbidity (95% CI, 1.48-111.42; P = 0.021 on multivariate logistic regression. Large decrease in SPP during CPB predicts postoperative 6 h hyperlactatemia and 30-day morbidity, which implicates a promising role of SPP monitoring in the achievement of optimal perfusion during CPB.

  5. Skin perfusion pressure as an indicator of tissue perfusion in valvular heart surgery: Preliminary results from a prospective, observational study.

    Science.gov (United States)

    Song, Young; Soh, Sarah; Shim, Jae-Kwang; Park, Kyoung-Un; Kwak, Young-Lan

    2017-01-01

    Hemodynamic management aims to provide adequate tissue perfusion, which is often altered during cardiac surgery with cardiopulmonary bypass (CPB). We evaluated whether skin perfusion pressure (SPP) can be used for monitoring of adequacy of tissue perfusion in patients undergoing valvular heart surgery. Seventy-two patients undergoing valve replacement were enrolled. SPP and serum lactate level were assessed after anaesthesia induction (baseline), during CPB, after CPB-off, end of surgery, arrival at intensive care unit, and postoperative 6 h. Lactate was further measured until postoperative 48 h. Association of SPP with lactate and 30-day morbidity comprising myocardial infarction, acute kidney injury, stroke, prolonged intubation, sternal infection, reoperation, and mortality was assessed. Among the lactate levels, postoperative 6 h peak value was most closely linked to composite of 30-day morbidity. The SPP value during CPB and its % change from the baseline value were significantly associated with the postoperative 6 h peak lactate (r = -0.26, P = 0.030 and r = 0.47, P = 0.001, respectively). Optimal cut-off of % decrease in SPP during CPB from baseline value for the postoperative 6 h hyperlactatemia was 48% (area under curve, 0.808; 95% confidence interval (CI), 0.652-0.963; P = 0.001). Decrease in SPP >48% during CPB from baseline value was associated with a 12.8-fold increased risk of composite endpoint of 30-day morbidity (95% CI, 1.48-111.42; P = 0.021) on multivariate logistic regression. Large decrease in SPP during CPB predicts postoperative 6 h hyperlactatemia and 30-day morbidity, which implicates a promising role of SPP monitoring in the achievement of optimal perfusion during CPB.

  6. A noninvasive estimation of cerebral perfusion pressure using critical closing pressure.

    Science.gov (United States)

    Varsos, Georgios V; Kolias, Angelos G; Smielewski, Peter; Brady, Ken M; Varsos, Vassilis G; Hutchinson, Peter J; Pickard, John D; Czosnyka, Marek

    2015-09-01

    Cerebral blood flow is associated with cerebral perfusion pressure (CPP), which is clinically monitored through arterial blood pressure (ABP) and invasive measurements of intracranial pressure (ICP). Based on critical closing pressure (CrCP), the authors introduce a novel method for a noninvasive estimator of CPP (eCPP). Data from 280 head-injured patients with ABP, ICP, and transcranial Doppler ultrasonography measurements were retrospectively examined. CrCP was calculated with a noninvasive version of the cerebrovascular impedance method. The eCPP was refined with a predictive regression model of CrCP-based estimation of ICP from known ICP using data from 232 patients, and validated with data from the remaining 48 patients. Cohort analysis showed eCPP to be correlated with measured CPP (R = 0.851, p area under the curve of 0.913 (95% CI 0.883-0.944). When each recording session of a patient was assessed individually, eCPP could predict CPP with a 95% CI of the SD for estimating CPP between multiple recording sessions of 1.89-5.01 mm Hg. Overall, CrCP-based eCPP was strongly correlated with invasive CPP, with sensitivity and specificity for detection of low CPP that show promise for clinical use.

  7. Initial intramuscular perfusion pressure predicts early skeletal muscle function following isolated tibial fractures

    Directory of Open Access Journals (Sweden)

    Haas Norbert P

    2008-04-01

    Full Text Available Abstract Background The severity of associated soft tissue trauma in complex injuries of the extremities guides fracture treatment and decisively determines patient's prognosis. Trauma-induced microvascular dysfunction and increased tissue pressure is known to trigger secondary soft tissue damage and seems to adversely affect skeletal muscle function. Methods 20 patients with isolated tibial fractures were included. Blood pressure and compartment pressure (anterior and deep posterior compartment were measured continuously up to 24 hours. Corresponding perfusion pressure was calculated. After 4 and 12 weeks isokinetic muscle peak torque and mean power of the ankle joint in dorsal and plantar flexion were measured using a Biodex dynamometer. Results A significant inverse correlation between the anterior perfusion pressure at 24 hours and deficit in dorsiflexion at 4 weeks was found for both, the peak torque (R = -0.83; p Conclusion The functional relationship between the decrease in intramuscular perfusion pressures and muscle performance in the early rehabilitation period indicate a causative and prognostic role of early posttraumatic microcirculatory derangements and skeletal muscle function. Therapeutic concepts aimed at effective muscle recovery, early rehabilitation, and decreased secondary tissue damage, should consider the maintenance of an adequate intramuscular perfusion pressure.

  8. Comparing effects of perfusion and hydrostatic pressure on gene profiles of human chondrocyte.

    Science.gov (United States)

    Zhu, Ge; Mayer-Wagner, Susanne; Schröder, Christian; Woiczinski, Matthias; Blum, Helmut; Lavagi, Ilaria; Krebs, Stefan; Redeker, Julia I; Hölzer, Andreas; Jansson, Volkmar; Betz, Oliver; Müller, Peter E

    2015-09-20

    Hydrostatic pressure and perfusion have been shown to regulate the chondrogenic potential of articular chondrocytes. In order to compare the effects of hydrostatic pressure plus perfusion (HPP) and perfusion (P) we investigated the complete gene expression profiles of human chondrocytes under HPP and P. A simplified bioreactor was constructed to apply loading (0.1 MPa for 2 h) and perfusion (2 ml) through the same piping by pressurizing the medium directly. High-density monolayer cultures of human chondrocytes were exposed to HPP or P for 4 days. Controls (C) were maintained in static cultures. Gene expression was evaluated by sequencing (RNAseq) and quantitative real-time PCR analysis. Both treatments changed gene expression levels of human chondrocytes significantly. Specifically, HPP and P increased COL2A1 expression and decreased COL1A1 and MMP-13 expression. Despite of these similarities, RNAseq revealed a list of cartilage genes including ACAN, ITGA10 and TNC, which were differentially expressed by HPP and P. Of these candidates, adhesion related molecules were found to be upregulated in HPP. Both HPP and P treatment had beneficial effects on chondrocyte differentiation and decreased catabolic enzyme expression. The study provides new insight into how hydrostatic pressure and perfusion enhance cartilage differentiation and inhibit catabolic effects. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Postpartum Vascular Dysfunction in the Reduced Uteroplacental Perfusion Model of Preeclampsia.

    Directory of Open Access Journals (Sweden)

    Lesley Brennan

    Full Text Available Preeclampsia is a disorder affecting 2-8% of all pregnancies, characterized by gestational hypertension (≥ 140/90 mmHg and proteinuria (≥300 mg over 24 hours diagnosed following the 20th week of pregnancy, and for which there is currently no available treatment. While the precise cause of preeclampsia is unknown, placental ischemia/hypoxia resulting from abnormal trophoblast invasion and maternal endothelial dysfunction are central characteristics. Preeclampsia is a major cause of both maternal and fetal morbidity and mortality in the perinatal period. In addition, women who have experienced preeclampsia are more likely to suffer cardiovascular disease later in life. The cause of this elevation in cardiovascular risk postpartum, however, is unknown. We hypothesize that there may be lasting vascular dysfunction following exposure to reduced uteroplacental perfusion during pregnancy that may contribute to increased cardiovascular risk postpartum. Using the rat reduced utero-placental perfusion pressure (RUPP model of preeclampsia, blood pressure was assessed in dams at gestational day 20, one and three months postpartum. Mesenteric artery and aortic function were assessed using wire myography. We demonstrated hypertension and increased mesenteric artery responses to phenylephrine at gestational day 20, with the latter due to a decreased contribution of nitric oxide without any change in methylcholine-induced relaxation. At one month postpartum, we demonstrated a small but significant vasoconstrictive phenotype that was due to an underlying loss of basal nitric oxide contribution. At three months postpartum, endothelium-dependent relaxation of the aorta demonstrated sensitivity to oxLDL and mesenteric arteries demonstrated decreased nitric oxide bioavailability with impaired methylcholine-induced relaxation; indicative of an early development of endothelial dysfunction. In summary, we have demonstrated impaired vascular function following

  10. Estimation of bone perfusion as a function of intramedullary pressure in sheep

    International Nuclear Information System (INIS)

    Rosenthal, M.S.; Lehner, C.E.; Pearson, D.W.; Kanikula, T.M.; Adler, G.G.; Venci, R.; Lanphier, E.H.; De Luca, P.M.

    1985-01-01

    It has been reported previously that following decompression (i.e. diving ascents) the intramedullary pressure (IMP) in bone can rise dramatically and possibly by the mechanism which can induce dysbaric osteonecrosis or the ''silent bends''. If the blood supply for the bone transverses the marrow compartment, than an increase in IMP could cause a temporary decrease in perfusion or hemostasis and hence ischemia leading to bone necrosis. To test this hypothesis, the authors measured the perfusion of bone in sheep as a function of IMP. The bone perfusion was estimated by measuring the perfusion-limited clearance of Ar-41 (Eγ=1293 keV, T/sub 1/2/=1.83 h) from the bone mineral matrix of sheep's tibia. The argon gas was formed in vivo by the fast neutron activation of Ca-44 to Ar-41 following the Ca-44(n,α) reaction. Clearance of Ar-41 was measured by time gated gamma-ray spectroscopy. These results indicate that an elevation of intramedullary pressure can decrease perfusion in bone and may cause bone necrosis

  11. Role of pressure in angiotensin II-induced renal injury: chronic servo-control of renal perfusion pressure in rats.

    Science.gov (United States)

    Mori, Takefumi; Cowley, Allen W

    2004-04-01

    Renal perfusion pressure was servo-controlled chronically in rats to quantify the relative contribution of elevated arterial pressure versus angiotensin II (Ang II) on the induction of renal injury in Ang II-induced hypertension. Sprague-Dawley rats fed a 4% salt diet were administered Ang II for 14 days (25 ng/kg per minute IV; saline only for sham rats), and the renal perfusion pressure to the left kidney was continuously servo-controlled to maintain a normal pressure in that kidney throughout the period of hypertension. An aortic occluder was implanted around the aorta between the two renal arteries and carotid and femoral arterial pressure were measured continuously throughout the experiment to determine uncontrolled and controlled renal perfusion pressure, respectively. Renal perfusion pressure of uncontrolled, controlled, and sham kidneys over the period of Ang II or saline infusion averaged 152.6+/-7.0, 117.4+/-3.5, and 110.7+/-2.2 mm Hg, respectively. The high-pressure uncontrolled kidneys exhibited tubular necrosis and interstitial fibrosis, especially prominent in the outer medullary region. Regional glomerular sclerosis and interlobular artery injury were also pronounced. Controlled kidneys were significantly protected from interlobular artery injury, juxtamedullary glomeruli injury, tubular necrosis, and interstitial fibrosis as determined by comparing the level of injury. Glomerular injury was not prevented in the outer cortex. Transforming growth factor (TGF)-beta and active NF-kappaB proteins determined by immunohistochemistry were colocalized in the uncontrolled kidney in regions of interstitial fibrosis. We conclude that the preferential juxtamedullary injury found in Ang II hypertension is largely induced by pressure and is probably mediated through the TGF-beta and NF-kappaB pathway.

  12. Spatial interaction between tissue pressure and skeletal muscle perfusion during contraction

    NARCIS (Netherlands)

    Donkelaar, van C.C.; Huyghe, J.M.R.J.; Vankan, W.J.; Drost, M.R.

    2001-01-01

    The vascular waterfall theory attributes decreased muscle perfusion during contraction to increased intramuscular pressure (P_IM ) and concomitant increase in venous resistance. Although P_IM is distributed during contractions, this theory does not account for heterogeneity.This study hypothesises

  13. Effects of perfusion pressure and insulin on (3H) cytochalasin B (CB) binding to control and diabetic rat hearts

    International Nuclear Information System (INIS)

    Pleta, M.; Chan, T.

    1987-01-01

    Using ( 3 H) CB, they attempted to quantitate the changes in the amount of glucose transporters in the plasma membrane (PM) and intracellular membranes (HSP) prepared from rat hearts perfused with insulin, under low and high pressure. Membranes isolated from non-perfused hearts showed a PM/HSP ratio of (0.593). Hearts perfused with low pressure showed a lower ratio of (0.474). Perfusion with insulin increased the ratio to (1.8), almost a 3-4 fold increase from low perfusion pressure. These data correlate with insulin effects in glucose transport and CB binding in the fat cells. High pressure perfusion increased the PM/HSP ratio by 1-2 fold. ( 3 H) 2-DG transport indicates a comparable increase in glucose uptake with high pressure, but with insulin only a 1.5 fold increase was observed. Initial data obtained from streptozotocin (STZ) injected diabetic rats indicate low CB binding in the PM fraction. Only insulin, but not high perfusion pressure increased PM/HSP ratio in the STZ-diabetic hearts. Their data imply that while both caused apparent translocation of glucose transporters, influences on cardiac glucose metabolism by work load are different. Furthermore, STZ induced diabetes affected only the high perfusion pressure-induced and not the insulin-stimulated change in CB binding

  14. Ischaemic wound complications in above-knee amputations in relation to the skin perfusion pressure

    DEFF Research Database (Denmark)

    Holstein, P

    1980-01-01

    Healing of the stumps in 59 above-knee amputations was correlated with the local skin perfusion pressure (SPP) measured preoperatively as the external pressure required to stop isotope washout using 131I-(-) or 125I-(-) antipyrine mixed with histamine. Out of the 11 cases with an SPP below 30 mm...... ischaemic wound complications in above-knee amputations as has previously been shown to be the case in below-knee amputations....

  15. Study of a new method for the evaluation of portal vein pressure by hepatic perfusion imaging

    International Nuclear Information System (INIS)

    Cheng Muhua; Ling Yunbiao; Pan Zhiheng; Zhang Feng; Chen Weizhen

    2002-01-01

    To study a new method for predication of portal vein pressure (PVP) by hepatic perfusion imaging. 25 hepato-cirrhotic cases and 13 normal controls were performed the hepatic perfusion imaging. According to two compartmental model the values of portal vein indexes (PVI) was calculated using curve slope, area and hepatic heart perfusion ratio methods etc. The relationship of PVI with different method to PVP was also observed. All PVI by three methods in hepatocirrhosis were higher than those in normal controls (P<0.01), and also positively correlated with the PVP, their correlated coefficients was 0.79, 0.60, 0.68 respectively. Among them the slope method was most markedly significant than normal control and closely correlated with PVP. PVI can sensitively reflect the changes of portal vein blood flow. And it was an atraumatic, simple method for the evaluation of PVP

  16. Hydrostatic determinants of cerebral perfusion

    International Nuclear Information System (INIS)

    Wagner, E.M.; Traystman, R.J.

    1986-01-01

    We examined the cerebral blood flow response to alterations in perfusion pressure mediated through decreases in mean arterial pressure, increases in cerebrospinal fluid (CSF) pressure, and increases in jugular venous (JV) pressure in 42 pentobarbital anesthetized dogs. Each of these three pressures was independently controlled. Cerebral perfusion pressure was defined as mean arterial pressure minus JV or CSF pressure, depending on which was greater. Mean hemispheric blood flow was measured with the radiolabeled microsphere technique. Despite 30-mm Hg reductions in mean arterial pressure or increases in CSF or JV pressure, CBF did not change as long as the perfusion pressure remained greater than approximately 60 mm Hg. However, whenever perfusion pressure was reduced to an average of 48 mm Hg, cerebral blood flow decreased 27% to 33%. These results demonstrate the capacity of the cerebral vascular bed to respond similarly to changes in the perfusion pressure gradient obtained by decreasing mean arterial pressure, increasing JV pressure or increasing CSF pressure, and thereby support the above definition of cerebral perfusion pressure

  17. Evaluation of portal hypertension: a comparison of the use of liver perfusion CT with wedge hepatic venous pressure and hepatic

    International Nuclear Information System (INIS)

    Chung, Dong Jin; Kim, Young Joong; Park, Yong Sung; Lee, Tae Hee; Kim, Chong Soo; Kang, Heung Keun

    2008-01-01

    We compared the hepatic perfusion indices obtained using hepatic perfusion CT with the wedge hepatic venous pressure (WHVP) and hepatic venous pressure gradient (HVPG) to determine the efficacy of the use of liver perfusion CT for the evaluation of portal hypertension. Thirty-five patients with liver cirrhosis underwent hepatic vein catheterization to measure WHVP and HVPG and underwent a liver perfusion CT examination. Arterial perfusion, portal perfusion, total perfusion and the hepatic perfusion index (HPI) were calculated by the methods described by Miles and Blomlely. The overall correlation coefficients (r) between the perfusion indices and WHVP and HVPG were calculated. An additional correlation coefficient of 23 alcoholic cirrhosis patients was calculated. Using Blomley's equation, HPI had a positive correlation with WHVP (r = .471; ρ < .05) and HVPG (r = .482; ρ < .05). For the alcoholic liver cirrhosis patients, HPI had a higher positive correlation with WHVP (r = .500; ρ < .05) and HVPG (r = .539; ρ < .05) than for the non-alcoholic cirrhosis patients. There was no statistical difference between the use of Miles' equation and Blomley's equation for the evaluation of portal hypertension. This preliminary study showed that HPI positively correlated with WHVP and HVPG, especially in alcoholic cirrhosis patients. Liver perfusion CT may be useful in the evaluation of portal hypertension

  18. Evaluation of portal hypertension: a comparison of the use of liver perfusion CT with wedge hepatic venous pressure and hepatic

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Dong Jin; Kim, Young Joong; Park, Yong Sung; Lee, Tae Hee [University of Konyang College of Medicine, Daejeon (Korea, Republic of); Kim, Chong Soo; Kang, Heung Keun [Chonbuk National University Medical School, Jeonju (Korea, Republic of)

    2008-09-15

    We compared the hepatic perfusion indices obtained using hepatic perfusion CT with the wedge hepatic venous pressure (WHVP) and hepatic venous pressure gradient (HVPG) to determine the efficacy of the use of liver perfusion CT for the evaluation of portal hypertension. Thirty-five patients with liver cirrhosis underwent hepatic vein catheterization to measure WHVP and HVPG and underwent a liver perfusion CT examination. Arterial perfusion, portal perfusion, total perfusion and the hepatic perfusion index (HPI) were calculated by the methods described by Miles and Blomlely. The overall correlation coefficients (r) between the perfusion indices and WHVP and HVPG were calculated. An additional correlation coefficient of 23 alcoholic cirrhosis patients was calculated. Using Blomley's equation, HPI had a positive correlation with WHVP (r = .471; {rho} < .05) and HVPG (r = .482; {rho} < .05). For the alcoholic liver cirrhosis patients, HPI had a higher positive correlation with WHVP (r = .500; {rho} < .05) and HVPG (r = .539; {rho} < .05) than for the non-alcoholic cirrhosis patients. There was no statistical difference between the use of Miles' equation and Blomley's equation for the evaluation of portal hypertension. This preliminary study showed that HPI positively correlated with WHVP and HVPG, especially in alcoholic cirrhosis patients. Liver perfusion CT may be useful in the evaluation of portal hypertension.

  19. Intraoperative intracranial pressure and cerebral perfusion pressure for predicting surgical outcome in severe traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Tai-Hsin Tsai

    2013-10-01

    Full Text Available Intraoperative intracranial pressure (ICP and cerebral perfusion pressure (CPP were evaluated for use as prognostic indicators after surgery for severe traumatic brain injury (TBI, and threshold ICP and CPP values were determined to provide guidelines for patient management. This retrospective study reviewed data for 66 patients (20 females and 46 males aged 13–83 years (average age, 48 years who had received decompressive craniectomy and hematoma evacuation for severe TBI. The analysis of clinical characteristics included Glascow Coma Scale score, trauma mechanism, trauma severity, cerebral hemorrhage type, hematoma thickness observed on computed tomography scan, Glasgow Outcome Scale score, and mortality. Patients whose treatment included ICP monitoring had significantly better prognosis (p < 0.001 and significantly lower mortality (p = 0.016 compared to those who did not receive ICP monitoring. At all three major steps of the procedure, i.e., creation of the burr hole, evacuation of the hematoma, and closing of the wound, intraoperative ICP and CPP values significantly differed. The ICP and CPP values were also significantly associated with surgical outcome in the severe TBI patients. Between hematoma evacuation and wound closure, ICP and CPP values differed by 6.8 ± 4.5 and 6.5 ± 4.6 mmHg, respectively (mean difference, 6 mmHg. Intraoperative thresholds were 14 mmHg for ICP and 56mmH for CPP. Monitoring ICP and CPP during surgery improves management of severe TBI patients and provides an early prognostic indicator. During surgery for severe TBI, early detection of increased ICP is also crucial for enabling sufficiently early treatment to improve surgical outcome. However, further study is needed to determine the optimal intraoperative ICP and CPP thresholds before their use as subjective guidelines for managing severe TBI patients.

  20. Abnormalities of Microcirculation and Intracranial and Cerebral Perfusion Pressures in Severe Brain Injury

    Directory of Open Access Journals (Sweden)

    Yu. A. Churlyaev

    2008-01-01

    Full Text Available Objective: to evaluate the states of microcirculation, cerebral perfusion intracranial pressures in patients with isolated severe brain injury (SBI and to determine their possible relationships. Subjects and methods. 148 studies were performed in 16 victims with SBI. According to the outcome of brain traumatic disease, the patients were divided into two groups: 1 those who had a good outcome (n=8 and 2 those who had a fatal outcome (n=8. Microcirculation was examined by skin laser Doppler flowmetry using a LAKK-01 capillary blood flow laser analyzer (LAZMA Research-and-Production Association, Russian Federation. All the victims underwent surgical interventions to remove epi-, subdural, and intracerebral hematomas. A Codman subdural/intraparenchymatous intracranial pressure (ICD sensor (Johnson & Johnson, United Kingdom was intraoperatively inserted in the victims. Cerebral perfusion pressure (CPP was calculated using the generally accepted formula: CPP = MBP (mean blood pressure — ICD. ICD, CPP, and microcirculation were studied on postoperative days 1, 3, 5, and 7. Their values were recorded simultaneously. Ninety and 58 studies were conducted in the group of patients with good and fatal outcomes, respectively. Results. No correlation between the changes in MBP, ICD, and microcirculatory parameters suggested that the value of ICD was determined by the nature of brain damage and it was the leading and determining indicator in the diagnosis and treatment of secondary cerebral lesions. The amplitude of low-frequency fluctuations directly correlated with ICD, which indicated that they might be used to evaluate cerebral perfusion and impaired cerebral circulation indirectly in victims with severe brain injury. Conclusion. The laser Doppler flowmetric technique makes it possible not only to qualitatively, but also quantitatively determine changes in the tissue blood flow system in severe brain injury. With this technique, both the local and central

  1. Sulphonylurea drugs reduce hypoxic damage in the isolated perfused rat kidney.

    Science.gov (United States)

    Engbersen, R; Moons, M M; Wouterse, A C; Dijkman, H B; Kramers, C; Smits, P; Russel, F G

    2000-08-01

    Sulphonylurea drugs have been shown to protect against hypoxic damage in isolated proximal tubules of the kidney. In the present study we investigated whether these drugs can protect against hypoxic damage in a whole kidney preparation. Tolbutamide (200 microM) and glibenclamide (10 microM) were applied to the isolated perfused rat kidney prior to changing the gassing from oxygen to nitrogen for 30 min. Hypoxic perfusions resulted in an increased fractional excretion of glucose (FE % glucose 14.3+/-1.5 for hypoxic perfusions vs 4.9+/-1.6 for normoxic perfusions, mean +/- s.e. mean, P<0.05), which could be completely restored by 200 microM tolbutamide (5.7+/-0.4 for tolbutamide vs 14.3+/-1.5 for untreated hypoxic kidneys, P<0.01). Furthermore, tolbutamide reduced the total amount of LDH excreted in the urine (220+/-100 mU for tolbutamide vs. 1220+/-160 mU for untreated hypoxic kidneys, P<0.01). Comparable results were obtained with glibenclamide (10 microM). In agreement with the effect on functional parameters, ultrastructural analysis of proximal tubules showed increased brush border preservation in tolbutamide treated kidneys compared to untreated hypoxic kidneys. We conclude that glibenclamide and tolbutamide are both able to reduce hypoxic damage to proximal tubules in the isolated perfused rat kidney when applied in the appropriate concentrations.

  2. Note: A micro-perfusion system for use during real-time physiological studies under high pressure

    Science.gov (United States)

    Maltas, Jeff; Long, Zac; Huff, Alison; Maloney, Ryan; Ryan, Jordan; Urayama, Paul

    2014-10-01

    We construct a micro-perfusion system using piston screw pump generators for use during real-time, high-pressure physiological studies. Perfusion is achieved using two generators, with one generator being compressed while the other is retracted, thus maintaining pressurization while producing fluid flow. We demonstrate control over perfusion rates in the 10-μl/s range and the ability to change between fluid reservoirs at up to 50 MPa. We validate the screw-pump approach by monitoring the cyanide-induced response of UV-excited autofluorescence from Saccharomyces cerevisiae under pressurization.

  3. Postural influence on intracranial and cerebral perfusion pressure in ambulatory neurosurgical patients

    DEFF Research Database (Denmark)

    Petersen, Lonnie Grove; Petersen, Johan Casper Grove; Andresen, Morten

    2016-01-01

    .4±4.2 mmHg when standing up (Phydrostatic pressure gradient with reference just below the heart, likely reflecting the venous hydrostatic...... indifference point. When upright, the decrease in ICP was attenuated, corresponding to formation of a separate hydrostatic gradient with reference to the base of the skull, likely reflecting the site of venous collapse. ICP therefore seems to be governed by pressure in the draining veins and collapse of neck......We evaluated postural effects on intracranial pressure (ICP) and cerebral perfusion pressure (CPP: mean arterial pressure (MAP) - ICP) in neurosurgical patients undergoing 24-hour ICP monitoring as part of their diagnostic workup. We identified 9 patients (5 women, age 44±20 yrs.; mean±SD) who were...

  4. Wound healing in above-knee amputations in relation to skin perfusion pressure

    DEFF Research Database (Denmark)

    Holstein, P; Dovey, H; Lassen, N A

    1979-01-01

    In 59 above-knee amputations healing of the stumps was correlated with the local skin perfusion pressure (SPP) measured preoperatively as the external pressure required to stop isotope washout using 1318-- or 125I--antipyrine mixed with histamine. Out of the 11 cases with an SPP below 30 mm...... on the stumps was on average only slightly and insignificantly higher than the preoperative values, explaining why the preoperative values related so closely to the postoperative clinical course. We conclude that the SPP can be used to predict ischaemic wound complications in above-knee amputations as has...... previously been shown to be the case in below-knee amputations....

  5. Improvements in the technique of vascular perfusion-fixation employing a fluorocarbon-containing perfusate and a peristaltic pump controlled by pressure feedback

    DEFF Research Database (Denmark)

    Rostgaard, J; Qvortrup, Klaus; Poulsen, Steen Seier

    1993-01-01

    A new improved technique for whole-body perfusion-fixation of rats and other small animals is described. The driving force is a peristaltic pump which is feedback regulated by a pressure transducer that monitors the blood-perfusion pressure in the left ventricle of the heart. The primary perfusate...... to cannulate the heart; the outer and inner barrels of the cannula are connected to the peristaltic pump and to the pressure transducer, respectively. The tissue oxygen tension in the rat is monitored by a subcutaneous oxygen electrode. Measurements showed that tissue hypoxia/anoxia did not develop before......-fixative is composed of a blood substitute--13.3% oxygenated fluorocarbon FC-75--in 0.05 M cacodylate buffer (pH 7.4) with a 2% glutaraldehyde. The secondary perfusate-fixative is composed of 2% glutaraldehyde in 0.05 M cacodylate buffer (pH 7.4) with 20 mM CaCl2. A double-barrelled, self-holding cannula is used...

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

    Science.gov (United States)

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

    2015-01-01

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

  7. Post Traumatic Cerebral Oedema in Severe Head Injury is Related to Intracranial Pressure and Cerebral Perfusion Pressure but not to Cerebral Compliance

    Directory of Open Access Journals (Sweden)

    U Nujaimin

    2009-07-01

    Full Text Available This was a prospective cohort study, carried out in the Neuro Intensive Care Unit, Department of Neurosciences, Hospital Universiti Sains Malaysia, Kubang Kerian Kelantan. The study was approved by the local ethics committee and was conducted between November 2005 and September 2007 with a total of 30 patients included in the study. In our study, univariate analysis showed a statistically significant relationship between mean intracranial pressure (ICP as well as cerebral perfusion pressure (CPP with both states of basal cistern and the degree of diffuse injury and oedema based on the Marshall classification system. The ICP was higher while CPP and compliance were lower whenever the basal cisterns were effaced in cases of cerebral oedema with Marshall III and IV. In comparison, the study revealed lower ICP, higher mean CPP and better mean cerebral compliance if the basal cisterns were opened or the post operative CT brain scan showed Marshall I and II. These findings suggested the surgical evacuation of clots to reduce the mass volume and restoration of brain anatomy may reduce vascular engorgement and cerebral oedema, therefore preventing intracranial hypertension, and improving cerebral perfusion pressure and cerebral compliance. Nevertheless the study did not find any significant relationship between midline shifts and mean ICP, CPP or cerebral compliance even though lower ICP, higher CPP and compliance were frequently observed when the midline shift was less than 0.5 cm. As the majority of our patients had multiple and diffuse brain injuries, the absence of midline shift did not necessarily mean lower ICP as the pathology was bilateral and even when after excluding the multiple lesions, the result remained insignificant. We assumed that the CT brain scan obtained after evacuation of the mass lesion to assess the state basal cistern and classify the diffuse oedema may prognosticate the intracranial pressure and cerebral perfusion pressure

  8. Bernoulli's Principle Applied to Brain Fluids: Intracranial Pressure Does Not Drive Cerebral Perfusion or CSF Flow.

    Science.gov (United States)

    Schmidt, Eric; Ros, Maxime; Moyse, Emmanuel; Lorthois, Sylvie; Swider, Pascal

    2016-01-01

    In line with the first law of thermodynamics, Bernoulli's principle states that the total energy in a fluid is the same at all points. We applied Bernoulli's principle to understand the relationship between intracranial pressure (ICP) and intracranial fluids. We analyzed simple fluid physics along a tube to describe the interplay between pressure and velocity. Bernoulli's equation demonstrates that a fluid does not flow along a gradient of pressure or velocity; a fluid flows along a gradient of energy from a high-energy region to a low-energy region. A fluid can even flow against a pressure gradient or a velocity gradient. Pressure and velocity represent part of the total energy. Cerebral blood perfusion is not driven by pressure but by energy: the blood flows from high-energy to lower-energy regions. Hydrocephalus is related to increased cerebrospinal fluid (CSF) resistance (i.e., energy transfer) at various points. Identification of the energy transfer within the CSF circuit is important in understanding and treating CSF-related disorders. Bernoulli's principle is not an abstract concept far from clinical practice. We should be aware that pressure is easy to measure, but it does not induce resumption of fluid flow. Even at the bedside, energy is the key to understanding ICP and fluid dynamics.

  9. Relationship between systemic hypertension, perfusion pressure and glaucoma: A comparative study in an adult Indian population

    Directory of Open Access Journals (Sweden)

    Amit K Deb

    2014-01-01

    Full Text Available Aims: To study the relationship between blood pressure (BP, intraocular pressure (IOP, mean ocular perfusion pressure (MOPP and primary open angle glaucoma (POAG in patients with hypertension and compare it to a control group of normotensives. Design: Cross-sectional observational study. Materials and Methods: A total of 108 subjects with primary hypertension and 100 age-matched controls without hypertension were enrolled for the study. IOP measurement using Noncontact Tonometer and dilated fundus evaluation using + 90 D lens were done for all cases. Single recording of BP was taken. Gonioscopy, Humphrey′s central visual fields, optical coherence tomography and pachymetry were done for all subjects with IOP > 21 mm Hg or C: D ratio ≥ 0.5 or asymmetry of > 0.2. Statistical Analysis: Univariate and multivariate multinomial regression models were used to determine the association between covariates and risk of glaucoma or glaucoma suspect. Results: There was no difference in the glaucoma status between subjects with and without hypertension. Subjects on antihypertensive medications were 1΍ times more likely to have suspicious glaucoma (odds ratio [OR] =1.56] and nearly twice as likely to have POAG (OR = 1.85. In addition, we found a 31% and 12% reduction in risk of having POAG (95% confidence interval [CI] =13-45%, P = 0.001 and glaucoma suspect (95% CI = 2-21%, P = 0.03 respectively with every 1 mm Hg increment in MOPP. Conclusion: Subjects on antihypertensive medications are more likely to have either glaucoma or glaucoma suspect, and higher ocular perfusion pressure offers relative protection from glaucomatous damage.

  10. The use of hemoglobin saturation ratio as a means of measuring tissue perfusion in the development of heel pressure sores.

    Science.gov (United States)

    Aliano, Kristen A; Stavrides, Steve; Davenport, Thomas

    2013-09-01

    The heel is a common site of pressure ulcers. The amount of pressure and time needed to develop these wounds is dependent on various factors including pressure surface, the patient's anatomy, and co-morbidities. We studied the use of the hemoglobin saturation ratio as a means of assessing heel perfusion in various pressure settings. The mixed perfusion ratio in the heels of 5 volunteers was assessed on 3 pressure surfaces and at the time of off-load. The surfaces studied included: stretcher pad, plastic backboard without padding, and pressure reduction gel. Each surface was measured for 5 minutes with a real-time reading. On the stretcher, the average StO2% decrease for each pressure surface was 26.2 ± 10 (range 18-43). The average StO2% decrease on the backboard was 22.8 ± 12.3 (range 8-37), and 24.0 ± 4.8 (range 19-30) on the gel pad. The StO2% drop plateaued with the stretcher and gel pad, but with the backboard there was a continued slow drop at 5 minutes. This study demonstrates that hemoglobin oxygenation ratio may be effective in assessing a tissue's direct perfusion in the setting of tissue pressure and may also be beneficial to better assess the effects of pressure-reduction surfaces. Further studies will be needed to determine time to skin breakdown as it pertains to pressure and tissue oxygenation.

  11. [How can we determine the best cerebral perfusion pressure in pediatric traumatic brain injury?].

    Science.gov (United States)

    Vuillaume, C; Mrozek, S; Fourcade, O; Geeraerts, T

    2013-12-01

    The management of cerebral perfusion pressure (CPP) is the one of the main preoccupation for the care of paediatric traumatic brain injury (TBI). The physiology of cerebral autoregulation, CO2 vasoreactivity, cerebral metabolism changes with age as well as the brain compliance. Low CPP leads to high morbidity and mortality in pediatric TBI. The recent guidelines for the management of CPP for the paediatric TBI indicate a CPP threshold 40-50 mmHg (infants for the lower and adolescent for the upper). But we must consider the importance of age-related differences in the arterial pressure and CPP. The best CPP is the one that allows to avoid cerebral ischaemia and oedema. In this way, the adaptation of optimal CPP must be individual. To assess this objective, interesting tools are available. Transcranial Doppler can be used to determine the best level of CPP. Other indicators can predict the impairment of autoregulation like pressure reactivity index (PRx) taking into consideration the respective changes in ICP and CPP. Measurement of brain tissue oxygen partial pressure is an other tool that can be used to determine the optimal CPP. Copyright © 2013 Société française d’anesthésie et de réanimation (Sfar). Published by Elsevier SAS. All rights reserved.

  12. Correlation between cerebral hemodynamic and perfusion pressure changes in non-human primates

    Science.gov (United States)

    Ruesch, A.; Smith, M. A.; Wollstein, G.; Sigal, I. A.; Nelson, S.; Kainerstorfer, J. M.

    2017-02-01

    The mechanism that maintains a stable blood flow in the brain despite changes in cerebral perfusion pressure (CPP), and therefore guaranties a constant supply of oxygen and nutrients to the neurons, is known as cerebral auto-regulation (CA). In a certain range of CPP, blood flow is mediated by a vasomotor adjustment in vascular resistance through dilation of blood vessels. CA is known to be impaired in diseases like traumatic brain injury, Parkinson's disease, stroke, hydrocephalus and others. If CA is impaired, blood flow and pressure changes are coupled and thee oxygen supply might be unstable. Lassen's blood flow auto-regulation curve describes this mechanism, where a plateau of stable blood flow in a specific range of CPP corresponds to intact auto-regulation. Knowing the limits of this plateau and maintaining CPP within these limits can improve patient outcome. Since CPP is influenced by both intracranial pressure and arterial blood pressure, long term changes in either can lead to auto-regulation impairment. Non-invasive methods for monitoring blood flow auto-regulation are therefore needed. We propose too use Near infrared spectroscopy (NIRS) too fill this need. NIRS is an optical technique, which measures microvascular changes in cerebral hemoglobin concentration. We performed experiments on non-human primates during exsanguination to demonstrate that thee limits of blood flow auto-regulation can be accessed with NIRS.

  13. Counteracting negative venous line pressures to avoid arterial air bubbles: an experimental study comparing two different types of miniaturized extracorporeal perfusion systems.

    Science.gov (United States)

    Aboud, Anas; Mederos-Dahms, Hendrikje; Liebing, Kai; Zittermann, Armin; Schubert, Harald; Murray, Edward; Renner, Andre; Gummert, Jan; Börgermann, Jochen

    2015-05-29

    Because of its low rate of clinical complications, miniaturized extracorporeal perfusion systems (MEPS) are frequently used in heart centers worldwide. However, many recent studies refer to the higher probability of gaseous microemboli formation by MEPS, caused by subzero pressure values. This is the main reason why various de-airing devices were developed for today's perfusion systems. In the present study, we investigated the potential benefits of a simple one-way-valve connected to a volume replacement reservoir (OVR) for volume and pressure compensation. In an experimental study on 26 pigs, we compared MEPS (n = 13) with MEPS plus OVR (n = 13). Except OVR, perfusion equipment was identical in both groups. Primary endpoints were pressure values in the venous line and the right atrium as well as the number and volume of air bubbles. Secondary endpoints were biochemical parameters of systemic inflammatory response, ischemia, hemodilution and hemolysis. One animal was lost in the MEPS + OVR group. In the MEPS + OVR group no pressure values below -150 mmHg in the venous line and no values under -100 mmHg in right atrium were noticed. On the contrary, nearly 20% of venous pressure values in the MEPS group were below -150 and approximately 10% of right atrial pressure values were below -100 mmHg. Compared with the MEPS group, the bubble counter device showed lower numbers of arterial air bubbles in the MEPS + OVR group (mean ± SD: 13444 ± 5709 vs. 1 ± 2, respectively; p pressures and to reduce the number and volume of arterial air bubbles. This approach may lead to a lower rate of neurological complications.

  14. Endoluminal isoproterenol reduces renal pelvic pressure during semirigid ureterorenoscopy

    DEFF Research Database (Denmark)

    Jakobsen, Jørn S; Jung, Helene U; Gramsbergen, Jan B

    2009-01-01

    OBJECTIVE To investigate the effects on the pressure-flow relation of renal pelvic pressure during semirigid ureterorenoscopy and endoluminal perfusion of isoproterenol (ISO) 0.1 microg/mL, with emphasis on local effects and cardiovascular side-effects, as topically administered ISO effectively...... and dose-dependently causes relaxation of the upper urinary tract in pigs with no concomitant cardiovascular side-effects. MATERIALS AND METHODS In anaesthetized female pigs (60 kg), 16 macroscopically normal upper urinary tract systems were subjected to ureterorenoscopy. Via a subcostal incision a 6-F...... catheter was placed in the renal pelvis for pressure measurements, and a semirigid ureteroscope (7.8 F) was inserted retrogradely in the renal pelvis, through which the pelvis was perfused. The blood pressure and heart rate were recorded. The increase in renal pelvic pressure was examined with increasing...

  15. Directly measuring spinal cord blood flow and spinal cord perfusion pressure via the collateral network: correlations with changes in systemic blood pressure.

    Science.gov (United States)

    Kise, Yuya; Kuniyoshi, Yukio; Inafuku, Hitoshi; Nagano, Takaaki; Hirayasu, Tsuneo; Yamashiro, Satoshi

    2015-01-01

    During thoracoabdominal surgery in which segmental arteries are sacrificed over a large area, blood supply routes from collateral networks have received attention as a means of avoiding spinal cord injury. The aim of this study was to investigate spinal cord blood supply through a collateral network by directly measuring spinal cord blood flow and spinal cord perfusion pressure experimentally. In beagle dogs (n = 8), the thoracoabdominal aorta and segmental arteries L1-L7 were exposed, and a temporary bypass was created for distal perfusion. Next, a laser blood flow meter was placed on the spinal dura mater in the L5 region to measure the spinal cord blood flow. The following were measured simultaneously when the direct blood supply from segmental arteries L2-L7 to the spinal cord was stopped: mean systemic blood pressure, spinal cord perfusion pressure (blood pressure within the aortic clamp site), and spinal cord blood flow supplied via the collateral network. These variables were then investigated for evidence of correlations. Positive correlations were observed between mean systemic blood pressure and spinal cord blood flow during interruption of segmental artery flow both with (r = 0.844, P flow with and without distal perfusion (r = 0.803, P network from outside the interrupted segmental arteries, and high systemic blood pressure (∼1.33-fold higher) was needed to obtain the preclamping spinal cord blood flow, whereas 1.68-fold higher systemic blood pressure was needed when distal perfusion was halted. Spinal cord blood flow is positively correlated with mean systemic blood pressure and spinal cord perfusion pressure under spinal cord ischemia caused by clamping a wide range of segmental arteries. In open and endovascular thoracic and thoracoabdominal surgery, elevating mean systemic blood pressure is a simple and effective means of increasing spinal cord blood flow, and measuring spinal cord perfusion pressure seems to be useful for monitoring

  16. Comparing CT perfusion with oxygen partial pressure in a rabbit VX2 soft-tissue tumor model.

    Science.gov (United States)

    Sun, Chang-Jin; Li, Chao; Lv, Hai-Bo; Zhao, Cong; Yu, Jin-Ming; Wang, Guang-Hui; Luo, Yun-Xiu; Li, Yan; Xiao, Mingyong; Yin, Jun; Lang, Jin-Yi

    2014-01-01

    The aim of this study was to evaluate the oxygen partial pressure of the rabbit model of the VX2 tumor using a 64-slice perfusion CT and to compare the results with that obtained using the oxygen microelectrode method. Perfusion CT was performed for 45 successfully constructed rabbit models of a VX2 brain tumor. The perfusion values of the brain tumor region of interest, the blood volume (BV), the time to peak (TTP) and the peak enhancement intensity (PEI) were measured. The results were compared with the partial pressure of oxygen (PO2) of that region of interest obtained using the oxygen microelectrode method. The perfusion values of the brain tumor region of interest in 45 successfully constructed rabbit models of a VX2 brain tumor ranged from 1.3-127.0 (average, 21.1 ± 26.7 ml/min/ml); BV ranged from 1.2-53.5 ml/100g (average, 22.2 ± 13.7 ml/100g); PEI ranged from 8.7-124.6 HU (average, 43.5 ± 28.7 HU); and TTP ranged from 8.2-62.3 s (average, 38.8 ± 14.8 s). The PO2 in the corresponding region ranged from 0.14-47 mmHg (average, 16 ± 14.8 mmHg). The perfusion CT positively correlated with the tumor PO2, which can be used for evaluating the tumor hypoxia in clinical practice.

  17. A National Trial on Differences in Cerebral Perfusion Pressure Values by Measurement Location.

    Science.gov (United States)

    McNett, Molly M; Bader, Mary Kay; Livesay, Sarah; Yeager, Susan; Moran, Cristina; Barnes, Arianna; Harrison, Kimberly R; Olson, DaiWai M

    2018-04-01

    Cerebral perfusion pressure (CPP) is a key parameter in management of brain injury with suspected impaired cerebral autoregulation. CPP is calculated by subtracting intracranial pressure (ICP) from mean arterial pressure (MAP). Despite consensus on importance of CPP monitoring, substantial variations exist on anatomical reference points used to measure arterial MAP when calculating CPP. This study aimed to identify differences in CPP values based on measurement location when using phlebostatic axis (PA) or tragus (Tg) as anatomical reference points. The secondary study aim was to determine impact of differences on patient outcomes at discharge. This was a prospective, repeated measures, multi-site national trial. Adult ICU patients with neurological injury necessitating ICP and CPP monitoring were consecutively enrolled from seven sites. Daily MAP/ICP/CPP values were gathered with the arterial transducer at the PA, followed by the Tg as anatomical reference points. A total of 136 subjects were enrolled, resulting in 324 paired observations. There were significant differences for CPP when comparing values obtained at PA and Tg reference points (p Differences remained significant in repeated measures model when controlling for clinical factors (mean CPP-PA = 80.77, mean CPP-Tg = 70.61, p identified as adequate with PA values, yet inadequate with CPP values measured at the Tg. Findings identify numerical differences for CPP based on anatomical reference location and highlight importance of a standard reference point for both clinical practice and future trials to limit practice variations and heterogeneity of findings.

  18. Tensile strength decreases and perfusion pressure of 3-holed polyamide epidural catheters increases in long-term epidural infusion.

    Science.gov (United States)

    Kim, Pascal; Meyer, Urs; Schüpfer, Guido; Rukwied, Roman; Konrad, Christoph; Gerber, Helmut

    2011-01-01

    Epidural analgesia is an established method for pain management. The failure rate is 8% to 12% due to technical difficulties (catheter dislocation and/or disconnection; partial or total catheter occlusion) and management. The mechanical properties of the catheters, like tensile strength and flow rate, may also be affected by the analgesic solution and/or the tissue environment. We investigated the tensile strength and perfusion pressure of new (n=20), perioperatively (n=30), and postoperatively (n=73) used epidural catheters (20-gauge, polyamide, closed tip, 3 side holes; Perifix [B. Braun]). To prevent dislocation, epidural catheters were taped (n=5) or fixed by suture (n=68) to the skin. After removal, mechanical properties were assessed by a tensile-testing machine (INSTRON 4500), and perfusion pressure was measured at flow rates of 10, 20, and 40 mL/h. All catheters demonstrated a 2-step force transmission. Initially, a minimal increase of length could be observed at 15 N followed by an elongation of several cm at additional forces (7 N). Breakage occurred in the control group at 23.5±1.5 N compared with 22.4±1.6 N in perioperative and 22.4±1.7 N in postoperative catheters (Ptensile strength, whereas perfusion pressure at clinically used flow rates (10 mL/h) increased significantly from 19±1.3 to 44±72 mm Hg during long-term (≥7 days) epidural analgesia (Ptensile strength or perfusion pressure. Epidural catheter use significantly increases the perfusion pressure and decreases the tensile strength. Copyright © 2011 by American Society of Regional Anesthesia and Pain Medicine

  19. Cerebral Perfusion Pressure Targets Individualized to Pressure-Reactivity Index in Moderate to Severe Traumatic Brain Injury: A Systematic Review.

    Science.gov (United States)

    Needham, Edward; McFadyen, Charles; Newcombe, Virginia; Synnot, Anneliese J; Czosnyka, Marek; Menon, David

    2017-03-01

    Traumatic brain injury (TBI) frequently triggers a disruption of cerebral autoregulation. The cerebral perfusion pressure (CPP) at which autoregulation is optimal ("CPPopt") varies between individuals, and can be calculated based on fluctuations between arterial blood pressure and intracranial pressure. This review assesses the effect of individualizing CPP targets to pressure reactivity index (a measure of autoregulation) in patients with TBI. Cochrane Central Register of Controlled Trials, MEDLINE®, Embase, and Cumulative Index of Nursing and Allied Health Literature were searched in March 2015 for studies assessing the effect of targeting CPPopt in TBI. We included all studies that assessed the impact of targeting CPPopt on outcomes including mortality, neurological outcome, and physiological changes. Risk of bias was assessed using the RTI Item Bank and evidence quality was considered using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) criteria. Eight cohort studies (based on six distinct data sets) assessing the association between CPPopt and mortality, Glasgow Outcome Scale and physiological measures in TBI were included. The quality of evidence was deemed very low based on the GRADE criteria. Although the data suggest an association between variation from CPPopt and poor clinical outcome at 6 months, the quality of evidence prevents firm conclusions, particularly regarding causality, from being drawn. Available data suggest that targeting CPPopt might represent a technique to improve outcomes following TBI, but currently there is insufficient high-quality data to support a recommendation for use in clinical practice. Further prospective, randomized controlled studies should be undertaken to clarify its role in the acute management of TBI.

  20. Effects of the ankle-brachial blood pressure index and skin perfusion pressure on mortality in hemodialysis patients.

    Science.gov (United States)

    Otani, Yumi; Otsubo, Shigeru; Kimata, Naoki; Takano, Mari; Abe, Takayuki; Okajima, Tomoki; Miwa, Naoko; Tsuchiya, Ken; Nitta, Kosaku; Akiba, Takashi

    2013-01-01

    Clinically, the ankle-brachial blood pressure index (ABI) and skin perfusion pressure (SPP) are used to screen for subclinical peripheral artery disease. However, the association between the SPP and mortality in hemodialysis patients has not been previously reported. We investigated these factors and compared the ABI and SPP in patients receiving hemodialysis. A total of 102 patients receiving maintenance hemodialysis were enrolled in this study. The ABI was determined using an ABI-form (Colin, Japan). The SPP was measured using a SensiLase(TM) PAD3000 (Kaneka, Osaka, Japan). The mean follow-up period was 3.2 ± 1.4 years. A multivariate Cox analysis identified a low ABI (p=0.019) and a low SPP (p=0.047) as being independent predictors of mortality. A receiver operating characteristic (ROC) analysis of the ABI revealed a cutoff point of 1.1 and an area under the curve (AUC) of 0.79, with a sensitivity of 90% and a specificity of 62%. A ROC analysis of the SPP revealed a cutoff point of 54.0 mmHg and an AUC of 0.71, with a sensitivity of 55% and a specificity of 84%. Both low ABI and SPP values were found to be independent risk factors for mortality among hemodialysis patients. The cutoff point for ABI as a predictor of mortality was 1.1, while that for SPP was 54.0 mmHg.

  1. Preserved regulation of renal perfusion pressure by small and intermediate conductance K-Ca channels in hypertensive mice with or without renal failure

    DEFF Research Database (Denmark)

    Waeckel, L.; Bertin, F.; Clavreul, N.

    2015-01-01

    -transgenic female mice expressing human angiotensinogen and renin (AR) genes received either control or a high-salt diet associated to a nitric oxide (NO) synthase inhibitor treatment (BLSL and ARSL). Changes in renal perfusion pressure (RPP) were measured in isolated perfused kidneys. BLSL and AR were moderately...

  2. Early effects of combretastatin-A4 disodium phosphate on tumor perfusion and interstitial fluid pressure

    DEFF Research Database (Denmark)

    Ley, C.D.; Horsman, Michael Robert; Kristjansen, P.E.G.

    2007-01-01

    /kg CA4DP by intraperitoneal injection. Tumor perfusion was recorded by laser Doppler flowmetry at separate time points, and IFP was recorded continuously by the wick-in-needle method. In this study, we found that CA4DP treatment resulted in a rapid reduction in tumor perfusion, followed by a decrease...

  3. Perfusion-induced changes in cardiac contractility depend on capillary perfusion.

    Science.gov (United States)

    Dijkman, M A; Heslinga, J W; Sipkema, P; Westerhof, N

    1998-02-01

    The perfusion-induced increase in cardiac contractility (Gregg phenomenon) is especially found in heart preparations that lack adequate coronary autoregulation and thus protection of changes in capillary pressure. We determined in the isolated perfused papillary muscle of the rat whether cardiac muscle contractility is related to capillary perfusion. Oxygen availability of this muscle is independent of internal perfusion, and perfusion may be varied or even stopped without loss of function. Muscles contracted isometrically at 27 degrees C (n = 7). During the control state stepwise increases in perfusion pressure resulted in all muscles in a significant increase in active tension. Muscle diameter always increased with increased perfusion pressure, but muscle segment length was unaffected. Capillary perfusion was then obstructed by plastic microspheres (15 microns). Flow, at a perfusion pressure of 66.6 +/- 26.2 cmH2O, reduced from 17.6 +/- 5.4 microliters/min in the control state to 3.2 +/- 1.3 microliters/min after microspheres. Active tension developed by the muscle in the unperfused condition before microspheres and after microspheres did not differ significantly (-12.8 +/- 29.4% change). After microspheres similar perfusion pressure steps as in control never resulted in an increase in active tension. Even at the two highest perfusion pressures (89.1 +/- 28.4 and 106.5 +/- 31.7 cmH2O) that were applied a significant decrease in active tension was found. We conclude that the Gregg phenomenon is related to capillary perfusion.

  4. Insulin resistance is associated with lower arterial blood flow and reduced cortical perfusion in cognitively asymptomatic middle-aged adults

    Science.gov (United States)

    Hoscheidt, Siobhan M; Kellawan, J Mikhail; Berman, Sara E; Rivera-Rivera, Leonardo A; Krause, Rachel A; Oh, Jennifer M; Beeri, Michal S; Rowley, Howard A; Wieben, Oliver; Carlsson, Cynthia M; Asthana, Sanjay; Johnson, Sterling C; Schrage, William G

    2016-01-01

    Insulin resistance (IR) is associated with poor cerebrovascular health and increased risk for dementia. Little is known about the unique effect of IR on both micro- and macrovascular flow particularly in midlife when interventions against dementia may be most effective. We examined the effect of IR as indexed by the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR) on cerebral blood flow in macro- and microvessels utilizing magnetic resonance imaging (MRI) among cognitively asymptomatic middle-aged individuals. We hypothesized that higher HOMA-IR would be associated with reduced flow in macrovessels and lower cortical perfusion. One hundred and twenty cognitively asymptomatic middle-aged adults (57 ± 5 yrs) underwent fasting blood draw, phase contrast-vastly undersampled isotropic projection reconstruction (PC VIPR) MRI, and arterial spin labeling (ASL) perfusion. Higher HOMA-IR was associated with lower arterial blood flow, particularly within the internal carotid arteries (ICAs), and lower cerebral perfusion in several brain regions including frontal and temporal lobe regions. Higher blood flow in bilateral ICAs predicted greater cortical perfusion in individuals with lower HOMA-IR, a relationship not observed among those with higher HOMA-IR. Findings provide novel evidence for an uncoupling of macrovascular blood flow and microvascular perfusion among individuals with higher IR in midlife. PMID:27488909

  5. Cerebral perfusion pressure, microdialysis biochemistry and clinical outcome in patients with traumatic brain injury

    Directory of Open Access Journals (Sweden)

    Paraforou Theoniki

    2011-12-01

    Full Text Available Abstract Background Traumatic Brain Injury (TBI is a major cause of death and disability. It has been postulated that brain metabolic status, intracranial pressure (ICP and cerebral perfusion pressure (CPP are related to patients' outcome. The aim of this study was to investigate the relationship between CPP, ICP and microdialysis parameters and clinical outcome in TBIs. Results Thirty four individuals with severe brain injury hospitalized in an intensive care unit participated in this study. Microdialysis data were collected, along with ICP and CPP values. Glasgow Outcome Scale (GOS was used to evaluate patient outcome at 6 months after injury. Fifteen patients with a CPP greater than 75 mmHg, L/P ratio lower than 37 and Glycerol concentration lower than 72 mmol/l had an excellent outcome (GOS 4 or 5, as opposed to the remaining 19 patients. No patient with a favorable outcome had a CPP lower than 75 mmHg or Glycerol concentration and L/P ratio greater than 72 mmol/l and 37 respectively. Data regarding L/P ratio and Glycerol concentration were statistically significant at p = 0.05 when patients with favorable and unfavorable outcome were compared. In a logistic regression model adjusted for age, sex and Glasgow Coma Scale on admission, a CPP greater than 75 mmHg was marginally statistically significantly related to outcome at 6 months after injury. Conclusions Patients with favorable outcome had certain common features in terms of microdialysis parameters and CPP values. An individualized approach regarding CPP levels and cut -off points for Glycerol concentration and L/P ratio are proposed.

  6. Comparing CT perfusion with oxygen partial pressure in a rabbit VX2 soft-tissue tumor model

    International Nuclear Information System (INIS)

    Sun Changjin; Li Chao; Lv Haibo

    2014-01-01

    The aim of this study was to evaluate the oxygen partial pressure of the rabbit model of the VX2 tumor using a 64-slice perfusion CT and to compare the results with that obtained using the oxygen microelectrode method. Perfusion CT was performed for 45 successfully constructed rabbit models of a VX2 brain tumor. The perfusion values of the brain tumor region of interest, the blood volume (BV), the time to peak (TTP) and the peak enhancement intensity (PEI) were measured. The results were compared with the partial pressure of oxygen (PO2) of that region of interest obtained using the oxygen microelectrode method. The perfusion values of the brain tumor region of interest in 45 successfully constructed rabbit models of a VX2 brain tumor ranged from 1.3–127.0 (average, 21.1 ± 26.7 ml/min/ml); BV ranged from 1.2–53.5 ml/100g (average, 22.2 ± 13.7 ml/100g); PEI ranged from 8.7–124.6 HU (average, 43.5 ± 28.7 HU); and TTP ranged from 8.2–62.3 s (average, 38.8 ± 14.8 s). The PO2 in the corresponding region ranged from 0.14–47 mmHg (average, 16 ± 14.8 mmHg). The perfusion CT positively correlated with the tumor PO2, which can be used for evaluating the tumor hypoxia in clinical practice. (author)

  7. Dietary red palm oil supplementation reduces myocardial infarct size in an isolated perfused rat heart model

    Directory of Open Access Journals (Sweden)

    Esterhuyse Adriaan J

    2010-06-01

    Full Text Available Abstract Background and Aims Recent studies have shown that dietary red palm oil (RPO supplementation improves functional recovery following ischaemia/reperfusion in isolated hearts. The main aim of this study was to investigate the effects of dietary RPO supplementation on myocardial infarct size after ischaemia/reperfusion injury. The effects of dietary RPO supplementation on matrix metalloproteinase-2 (MMP2 activation and PKB/Akt phosphorylation were also investigated. Materials and methods Male Wistar rats were divided into three groups and fed a standard rat chow diet (SRC, a SRC supplemented with RPO, or a SRC supplemented with sunflower oil (SFO, for a five week period, respectively. After the feeding period, hearts were excised and perfused on a Langendorff perfusion apparatus. Hearts were subjected to thirty minutes of normothermic global ischaemia and two hours of reperfusion. Infarct size was determined by triphenyltetrazolium chloride staining. Coronary effluent was collected for the first ten minutes of reperfusion in order to measure MMP2 activity by gelatin zymography. Results Dietary RPO-supplementation decreased myocardial infarct size significantly when compared to the SRC-group and the SFO-supplemented group (9.1 ± 1.0% versus 30.2 ± 3.9% and 27.1 ± 2.4% respectively. Both dietary RPO- and SFO-supplementation were able to decrease MMP2 activity when compared to the SRC fed group. PKB/Akt phosphorylation (Thr 308 was found to be significantly higher in the dietary RPO supplemented group when compared to the SFO supplemented group at 10 minutes into reperfusion. There was, however, no significant changes observed in ERK phosphorylation. Conclusions Dietary RPO-supplementation was found to be more effective than SFO-supplementation in reducing myocardial infarct size after ischaemia/reperfusion injury. Both dietary RPO and SFO were able to reduce MMP2 activity, which suggests that MMP2 activity does not play a major role in

  8. Postural effects on intraocular pressure and ocular perfusion pressure in patients with non-arteritic anterior ischemic optic neuropathy.

    Science.gov (United States)

    Yang, Jee Myung; Park, Sang Woo; Ji, Yong Sok; Kim, Jaeryung; Yoo, Chungkwon; Heo, Hwan

    2017-04-20

    To investigate postural effects on intraocular pressure (IOP) and ocular perfusion pressure (OPP) in patients with non-arteritic ischemic optic neuropathy (NAION). IOP and blood pressure (BP) were measured in 20 patients with unilateral NAION 10 min after changing to each of the following positions sequentially: sitting, supine, right lateral decubitus position (LDP), supine, left LDP, and supine. IOP was measured using a rebound tonometer and OPP was calculated using formulas based on mean BP. The dependent LDP (DLDP) was defined as the position when the eye of interest (affected or unaffected eye) was placed on the dependent side in the LDP. IOPs were significantly higher (P = 0.020) and OPPs were significantly lower (P = 0.041) in the affected eye compare with the unaffected eye, with the affected eye in DLDP. Compared with the mean IOP of the unaffected eyes, the mean IOP of the affected eyes increased significantly (+2.9 ± 4.4 versus +0.7 ± 3.1 mmHg, respectively; P = 0.003) and the mean OPP decreased significantly (-6.7 ± 9.4 versus -4.9 ± 8.0 mmHg, respectively; P = 0.022) after changing positions from supine to DLDP. In addition, changing position from supine to DLDP showed significantly larger absolute changes in IOP (4.13 ± 3.19 mmHg versus 2.51 ± 1.92 mmHg, respectively; P = 0.004) and OPP (9.86 ± 5.69 mmHg versus 7.50 ± 5.49 mmHg, respectively; P = 0.009) in the affected eye compared with the unaffected eye. In the affected eye, there was a significant positive correlation between absolute change in IOP and OPP when changing position from supine to DLDP (Rho = 0.512, P = 0.021). A postural change from supine to DLDP caused significant fluctuations in IOP and OPP of the affected eye, and may significantly increase IOP and decrease OPP. Posture-induced IOP changes may be a predisposing factor for NAION development.

  9. Adding attenuation corrected images in myocardial perfusion imaging reduces the need for a rest study

    International Nuclear Information System (INIS)

    Trägårdh, Elin; Valind, Sven; Edenbrandt, Lars

    2013-01-01

    The American Society of Nuclear Cardiology and the Society of Nuclear Medicine conclude that incorporation of attenuation corrected (AC) images in myocardial perfusion scintigraphy (MPS) will improve diagnostic accuracy. The aim was to investigate the value of adding AC stress-only images for the decision whether a rest study is necessary or not. 1,261 patients admitted to 99m Tc MPS were studied. The stress studies were interpreted by two physicians who judged each study as “no rest study necessary” or “rest study necessary”, by evaluating NC stress-only and NC + AC stress-only images. When there was disagreement between the two physicians, a third physician evaluated the studies. Thus, agreement between 2 out of 3 physicians was evaluated. The physicians assessed 214 more NC + AC images than NC images as “no rest study necessary” (17% of the study population). The number of no-rest-study-required was significantly higher for NC + AC studies compared to NC studies (859 vs 645 cases (p < 0.0001). In the final report according to clinical routine, ischemia or infarction was reported in 23 patients, assessed as “no rest study necessary” (22 NC + AC cases; 8 NC cases), (no statistically significant difference). In 11 of these, the final report stated “suspected/possible ischemia or infarction in a small area”. Adding AC stress-only images to NC stress-only images reduce the number of unnecessary rest studies substantially

  10. Closed-loop control of renal perfusion pressure in physiological experiments.

    Science.gov (United States)

    Campos-Delgado, D U; Bonilla, I; Rodríguez-Martínez, M; Sánchez-Briones, M E; Ruiz-Hernández, E

    2013-07-01

    This paper presents the design, experimental modeling, and control of a pump-driven renal perfusion pressure (RPP)-regulatory system to implement precise and relatively fast RPP regulation in rats. The mechatronic system is a simple, low-cost, and reliable device to automate the RPP regulation process based on flow-mediated occlusion. Hence, the regulated signal is the RPP measured in the left femoral artery of the rat, and the manipulated variable is the voltage applied to a dc motor that controls the occlusion of the aorta. The control system is implemented in a PC through the LabView software, and a data acquisition board NI USB-6210. A simple first-order linear system is proposed to approximate the dynamics in the experiment. The parameters of the model are chosen to minimize the error between the predicted and experimental output averaged from eight input/output datasets at different RPP operating conditions. A closed-loop servocontrol system based on a pole-placement PD controller plus dead-zone compensation was proposed for this purpose. First, the feedback structure was validated in simulation by considering parameter uncertainty, and constant and time-varying references. Several experimental tests were also conducted to validate in real time the closed-loop performance for stepwise and fast switching references, and the results show the effectiveness of the proposed automatic system to regulate the RPP in the rat, in a precise, accurate (mean error less than 2 mmHg) and relatively fast mode (10-15 s of response time).

  11. Predictive value of skin perfusion pressure after endovascular therapy for wound healing in critical limb ischemia.

    Science.gov (United States)

    Utsunomiya, Makoto; Nakamura, Masato; Nagashima, Yoshinori; Sugi, Kaoru

    2014-10-01

    To determine the predictive value of skin perfusion pressure (SPP) for wound healing after endovascular therapy (EVT). Between May 2004 and March 2011, 113 consecutive patients (84 men; mean age 71.5±12.5 years) with CLI (123 limbs) underwent successful balloon angioplasty ± stenting (flow from >1 vessel to the foot without bypass) and were physically able to undergo SPP measurement before and within 48 hours after EVT. The status of wound healing was recorded over a mean follow-up of 17.4±12.4 months. The wound healing rate was 78.9% (97 limbs of 89 patients). SPP values after EVT were significantly higher in these patients than in the 24 patients (26 limbs) without wound healing (44.2±15.6 mmHg vs. 27.5±10.4 mmHg, pwound healing had an area under the curve of 0.81 (95% CI 0.723 to 0.899, pwound healing was 30 mmHg, with a sensitivity of 81.4% and a specificity of 69.2%. Binary logistic regression analysis demonstrated SPP after EVT to be an independent predictor of wound healing (pwound healing with SPP values >30 mmHg, 40 mmHg, and 50 mmHg were 69.8%, 86.3%, and 94.5%, respectively. SPP after EVT is an independent predictor of wound healing in patients with CLI. In our study, an SPP value of 30 mmHg was shown to be the best cutoff for prediction of wound healing after EVT.

  12. Effects of topical hypotensive drugs on circadian IOP, blood pressure, and calculated diastolic ocular perfusion pressure in patients with glaucoma.

    Science.gov (United States)

    Quaranta, Luciano; Gandolfo, Federico; Turano, Raffaele; Rovida, Federico; Pizzolante, Teodoro; Musig, Andrea; Gandolfo, Enrico

    2006-07-01

    To compare the short-term effects of timolol 0.5%, brimonidine 0.2%, dorzolamide 2%, and latanoprost 0.005% on intraocular pressure (IOP), blood pressure (BP), and diastolic ocular perfusion pressure (DOPP), calculated as the difference between the diastolic blood pressure (DBP) and IOP. According to a 4 x 4 Latin squares design for repeated measures, 27 untreated patients and patients with newly diagnosed primary open-angle glaucoma (POAG) were treated with timolol 0.5% at 8 AM and 8 PM; brimonidine 0.2% at 8 AM and 8 PM; dorzolamide 2% at 8 AM, 2 PM, and 8 PM; and latanoprost 0.005% at 8 PM. The duration of each treatment course was 6-weeks, with a 4-week washout between each treatment. IOP and BP were measured at baseline and at the end of each treatment period. IOP was measured every 2 hours throughout a 24-hour period. Sitting IOP was measured from 8 AM to 10 PM by Goldmann applanation tonometry. Supine IOP was assessed from 12 to 6 AM by means of a handheld electronic tonometer (TonoPen XL; Mentor, Norwell, MA). BP monitoring was performed by means of an automated portable device (TM-2430; A & D Co., Saitama, Japan). All the drugs tested decreased the IOP significantly at all time points in comparison with baseline pressure. The mean 24-hour IOP after latanoprost administration (16.62+/-0.98 mm Hg) was significantly lower than that after timolol, brimonidine, or dorzolamide (P=0.0001). During the 24-hour period, brimonidine induced a significant decrease in systolic BP (SBP) and DBP at all time points when compared with baseline measurements and with those after administration of the other drugs (P<0.0001). Timolol caused a significant decrease in DBP and SBP at all the 24-hour time points when compared with the baseline and with the dorzolamide- and latanoprost-induced changes (P<0.0001). The mean 24-hour DOPPs were 50.7+/-5.9 mm Hg at baseline, 53+/-5.5 mm Hg with timolol, 46.2+/-5.4 mm Hg with brimonidine, 55.9+/-4.6 mm Hg with dorzolamide, and 56

  13. Effect of altered arterial perfusion pressure on vascular conductance and muscle blood flow dynamic response during exercise in humans.

    Science.gov (United States)

    Villar, Rodrigo; Hughson, Richard L

    2013-03-01

    Changes in vascular conductance (VC) are required to counter changes in muscle perfusion pressure (MPP) to maintain muscle blood flow (MBF) during exercise. We investigated the recruitment of VC as a function of peak VC measured in three body positions at two different work rates to test the hypothesis that adaptations in VC compensated changes in MPP at low-power output (LPO), but not at high-power output (HPO). Eleven healthy volunteers exercised at LPO and HPO (repeated plantar flexion contractions at 20-30% maximal voluntary contraction, respectively) in horizontal (HOR), 35° head-down tilt (HDT), and 45° head-up tilt (HUT). Muscle blood flow velocity and popliteal diameter were measured by ultrasound to determine MBF, and VC was estimated by dividing MBF flow by MPP. Peak VC was unaffected by body position. The rates of increase in MBF and VC were significantly faster in HUT and slower in HDT than HOR, and rates were faster in LPO than HPO. During LPO exercise, the increase in, and steady-state values of, MBF were less for HUT and HDT than HOR; the increase in VC was less in HUT than HOR and HDT. During HPO exercise, MBF in the HDT was reduced compared with HOR and HUT, even though VC reached 92% VC peak, which was greater than HOR, which was, in turn, greater than HUT. Reduced MBF during HPO HDT exercise had the functional consequence of a significant increase in muscle electromyographic index, revealing the effects of MPP on O2 delivery during exercise.

  14. Normothermic machine perfusion reduces bile duct injury and improves biliary epithelial function in rat donor livers.

    Science.gov (United States)

    Op den Dries, Sanna; Karimian, Negin; Westerkamp, Andrie C; Sutton, Michael E; Kuipers, Michiel; Wiersema-Buist, Janneke; Ottens, Petra J; Kuipers, Jeroen; Giepmans, Ben N; Leuvenink, Henri G D; Lisman, Ton; Porte, Robert J

    2016-07-01

    Bile duct injury may occur during liver procurement and transplantation, especially in livers from donation after circulatory death (DCD) donors. Normothermic machine perfusion (NMP) has been shown to reduce hepatic injury compared to static cold storage (SCS). However, it is unknown whether NMP provides better preservation of bile ducts. The aim of this study was to determine the impact of NMP on bile duct preservation in both DCD and non-DCD livers. DCD and non-DCD livers obtained from Lewis rats were preserved for 3 hours using either SCS or NMP, followed by 2 hours ex vivo reperfusion. Biomarkers of bile duct injury (gamma-glutamyltransferase and lactate dehydrogenase in bile) were lower in NMP-preserved livers compared to SCS-preserved livers. Biliary bicarbonate concentration, reflecting biliary epithelial function, was 2-fold higher in NMP-preserved livers (P bile was significantly higher in NMP-preserved livers (7.63 ± 0.02 and 7.74 ± 0.05 for non-DCD and DCD livers, respectively) compared with SCS-preserved livers (7.46 ± 0.02 and 7.49 ± 0.04 for non-DCD and DCD livers, respectively). Scanning and transmission electron microscopy of donor extrahepatic bile ducts demonstrated significantly decreased injury of the biliary epithelium of NMP-preserved donor livers (including the loss of lateral interdigitations and mitochondrial injury). Differences between NMP and SCS were most prominent in DCD livers. Compared to conventional SCS, NMP provides superior preservation of bile duct epithelial cell function and morphology, especially in DCD donor livers. By reducing biliary injury, NMP could have an important impact on the utilization of DCD livers and outcome after transplantation. Liver Transplantation 22 994-1005 2016 AASLD. © 2016 American Association for the Study of Liver Diseases.

  15. Extracellular Vesicles from Human Liver Stem Cells Reduce Injury in an Ex Vivo Normothermic Hypoxic Rat Liver Perfusion Model.

    Science.gov (United States)

    Rigo, Federica; De Stefano, Nicola; Navarro-Tableros, Victor; David, Ezio; Rizza, Giorgia; Catalano, Giorgia; Gilbo, Nicholas; Maione, Francesca; Gonella, Federica; Roggio, Dorotea; Martini, Silvia; Patrono, Damiano; Salizzoni, Mauro; Camussi, Giovanni; Romagnoli, Renato

    2018-05-01

    The gold standard for organ preservation before transplantation is static cold storage, which is unable to fully protect suboptimal livers from ischemia/reperfusion injury. An emerging alternative is normothermic machine perfusion (NMP), which permits organ reconditioning. Here, we aimed to explore the feasibility of a pharmacological intervention on isolated rat livers by using a combination of NMP and human liver stem cells-derived extracellular vesicles (HLSC-EV). We established an ex vivo murine model of NMP capable to maintain liver function despite an ongoing hypoxic injury induced by hemodilution. Livers were perfused for 4 hours without (control group, n = 10) or with HLSC-EV (treated group, n = 9). Bile production was quantified; perfusate samples were collected hourly to measure metabolic (pH, pO2, pCO2) and cytolysis parameters (AST, alanine aminotransferase, lactate dehydrogenase). At the end of perfusion, we assessed HLSC-EV engraftment by immunofluorescence, tissue injury by histology, apoptosis by terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, tissue hypoxia-inducible factor 1-α, and transforming growth factor-beta 1 RNA expression by quantitative reverse transcription-polymerase chain reaction. During hypoxic NMP, livers were able to maintain homeostasis and produce bile. In the treated group, AST (P = 0.018) and lactate dehydrogenase (P = 0.032) levels were significantly lower than those of the control group at 3 hours of perfusion, and AST levels persisted lower at 4 hours (P = 0.003). By the end of NMP, HLSC-EV had been uptaken by hepatocytes, and EV treatment significantly reduced histological damage (P = 0.030), apoptosis (P = 0.049), and RNA overexpression of hypoxia-inducible factor 1-α (P < 0.0001) and transforming growth factor-beta 1 (P = 0.014). HLSC-EV treatment, even in a short-duration model, was feasible and effectively reduced liver injury during hypoxic NMP.

  16. Effects of Topical Bimatoprost 0.01% and Timolol 0.5% on Circadian IOP, Blood Pressure and Perfusion Pressure in Patients with Glaucoma or Ocular Hypertension: A Randomized, Double Masked, Placebo-Controlled Clinical Trial.

    Directory of Open Access Journals (Sweden)

    Francesco Oddone

    Full Text Available To compare the 24-hour (24h effects on intraocular pressure (IOP and cardiovascular parameters of timolol 0.5% and bimatoprost 0.01% in open angle glaucoma and ocular hypertensive subjects.In this prospective, randomized, double masked, crossover, clinical trial, after washout from previous medications enrolled subjects underwent 24h IOP, blood pressure (BP and heart rate (HR measurements and were randomized to either topical bimatoprost 0.01% at night plus placebo in the morning or to timolol 0.5% bid. After 8 weeks of treatment a second 24h assessment of IOP, BP and HR was performed and then subjects switched to the opposite treatment for additional 8 weeks when a third 24h assessment was performed. The primary endpoint was the comparison of the mean 24h IOP after each treatment. Secondary endpoints included the comparisons of IOP at each timepoint of the 24h curve and the comparison of BP, HR, ocular perfusion pressure and tolerability.Mean untreated 24h IOP was 20.3 mmHg (95%CI 19.0 to 21.6. Mean 24h IOP was significantly lower after 8 weeks of treatment with bimatoprost 0.01% than after 8 weeks of treatment with timolol 0.5% bid (15.7 vs 16.8 mmHg, p = 0.0003. Mean IOP during the day hours was significantly reduced from baseline by both drugs while mean IOP during the night hours was reduced by -2.3 mmHg (p = 0.0002 by bimatoprost 0.01% plus placebo and by -1.1 mmHg by timolol 0.5% bid (p = 0.06. Timolol 0.5% significantly reduced the mean 24h systolic BP from baseline, the diastolic BP during the day hours, the HR during the night hours, and the mean 24h systolic ocular perfusion pressure.Both Bimatoprost 0.01% and Timolol 0.5% are effective in reducing the mean 24h IOP from an untreated baseline but Bimatoprost 0.01% is more effective than timolol 0.5% throughout the 24h. Timolol 0.5% effect on IOP is reduced during the night hours and is associated with reduced BP, HR and ocular perfusion pressure.EU Clinical Trial Register and Eudra

  17. Does Improvised Waterbed Reduce the Incidence of Pressure ...

    African Journals Online (AJOL)

    Does Improvised Waterbed Reduce the Incidence of Pressure Ulcers in Patients with Spinal Injury? ... The use of bed replacements markedly reduces the incidence of pressure ... Keywords: Neurological deficits, plastic sachet, table water ...

  18. Overexpression of thrombospondin-1 reduces growth and vascular index but not perfusion in glioblastoma

    DEFF Research Database (Denmark)

    Kragh, Michael; Quistorff, Bjørn; Tenan, Mirna

    2002-01-01

    Little is known about the effects of antiangiogenic therapy on perfusion of human tumors and the mechanisms by which tumors can adapt to these treatments and recur. Here, we examined the effects of serial passaging of LN-229 human glioma xenografts overexpressing thrombospondin (TSP)-1 on tumor...... vascularity was estimated by noninvasive near infrared spectroscopy measuring blood volume at 800 +/- 10 nm and by histological vessel scores in CD31-immunostained cryosections. The tumor perfusion was assessed by noninvasive laser Doppler flowmetry. Overexpression of TSP-1 significantly inhibited tumor....... Elucidation of the mechanisms that allow this to happen has important consequences for the understanding of tumor recurrence after antiangiogenic therapy....

  19. Heat-washout measurements compared to distal blood pressure and perfusion in orthopaedic patients with foot ulcers

    DEFF Research Database (Denmark)

    Midttun, M; Azad, B B S; Broholm, R

    2015-01-01

    Distal blood pressure and local skin perfusion pressure were compared to measurement of blood flow rate (BFR) measured by the heat-washout method in orthopaedic patients with and without diabetes, all with a foot ulcer in one foot, compared to healthy controls. The correlation was good between heat......-washout and distal blood pressure in patients with diabetes with and without an ulcer (P = 0·024 and 0·059, respectively). The correlation was weak in patients without diabetes with and without an ulcer, most probably due to power problems (P = 0·118 and 0·116, respectively). The correlation in the healthy controls...... the surrounding tissue, and therefore, measurements are easier made in these subjects. BFR in the first toe increased significantly in all patients when the foot was moved from heart level to 50 cm below heart level (P = between 0·03 and 0·05) as previously seen in patients with claudication...

  20. Reduced myocardial perfusion reserve in myocardium having coronary artery aneurysm of Kawasaki disease

    International Nuclear Information System (INIS)

    Yoon, S. N.; Lee, D. S.; Choi, J. Y.; Kil, H. R.; Jeong, Z. K.; Lee, M. C.; Ko, C. S.

    1997-01-01

    Kawasaki disease is a systemic vasculitis involving the coronary arteries at early childhood and cause coronary artery aneurysms and thrombotic occlusions. These coronary artery aneurysms were usually transformed later into stenotic or obstructive lesions, however, the majority of these aneurysms, even the giant ones, are known to be associated with normal epicardial coronary flow. Flow reserve is difficult to assess in aneurysmal arteries with echo or angiography. We performed this study to question if there are abnormalities in flow reserve in myocardial tissue with normal epicardial arterial flow on angiography in patients with Kawasaki disease, dipyridamole stress and rest Tc-99m-sestamibi SPECT were performed in 37 patients (28 boys, 9 girls, mean age 6.6 years). We compared SPECT findings with coronary angiography (CAG) findings in 21 patients who did both studies after finding abnormality on echocardiaography. On CAG, aneurysms were found in 26 arteries of 16 patients, i.e., 10 left main arteries, 6 left anterior descending arteries (LAD), 2 left circumflex arteries (LCX), and 8 right coronary arteries (RCA). Localized and segmental stenotic lesions were found in 11 arteries in 9 patients (LAD: 4, LCX: 1, RCA: 6). Eight of the 10 patients with aneurysms had no obvious stenosis. On stress-rest SPECT, 16(43%) out of 37 patients showed normal perfusion and the other 21(57%) showed reversible or persistent decrease. Among 11 stenotic artery territories, 3(27%) showed persistent and/or reversible perfusion defects. The other 8 were normal. Among 26 aneurysmal artery territories, 12 artery territories showe perfusion decrease. Three of the 5 patients with normal CAG showed persistent and/or transient perfusion defects. Among 14 artery territories with perfusion decrease in the 16 patients, 3(21%) could be localized to vascular territory having stenosis of supplying coronary arteries, 12(86%) were related to the coronary artery aneurysms. Two were not related to

  1. Increased perfusion pressure enhances the expression of endothelin (ETB) and angiotensin II (AT1, AT2) receptors in rat mesenteric artery smooth muscle cells

    DEFF Research Database (Denmark)

    Lindstedt, Isak; Xu, Cang-Bao; Zhang, Yaping

    2009-01-01

    and luminally perfused in a perfusion chamber. After either exposure to no ("organ culture" (0 mmHg)), normal (85/75 mmHg) or high pressure (160/150 mmHg) at constant flow for 1-17 h, the vessel segments were snap frozen and real-time polymerase chain reaction was performed to quantify the ET- and AT-receptor m...

  2. Reducing pressure oscillations in discrete fluid power systems

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen

    2016-01-01

    Discrete fluid power systems featuring transmission lines inherently include pressure oscillations. Experimental verification of a discrete fluid power power take off system for wave energy converters has shown the cylinder pressure to oscillate as force shifts are performed. This article investi...... investigates how cylinder pressure oscillations may be reduced by shaping the valve opening trajectory without the need for closed loop pressure feedback. Furthermore the energy costs of reducing pressure oscillations are investigated....

  3. Haemoadsorption reduces the inflammatory response and improves blood flow during ex vivo renal perfusion in an experimental model.

    Science.gov (United States)

    Hosgood, Sarah A; Moore, Tom; Kleverlaan, Theresa; Adams, Tom; Nicholson, Michael L

    2017-10-25

    Ex-vivo normothermic perfusion strategies are a promising new instrument in organ transplantation. The perfusion conditions are designed to be protective however the artificial environment can induce a local inflammatory response. The aim of this study was to determine the effect of incorporating a Cytosorb adsorber into an isolated kidney perfusion system. Porcine kidneys were subjected to 22 h of cold ischaemia then reperfused for 6 h on an ex vivo reperfusion circuit. Pairs of kidneys were randomised to either control (n = 5) or reperfusion with a Cytosorb adsorber (n = 5) integrated into the circuit. Tissue, blood and urine samples were taken for the measurement of inflammation and renal function. Baseline levels of cytokines (IL-6, TNFα, IL-8, IL-10, IL-1β, IL-1α) were similar between groups. Levels of IL-6 and IL-8 in the perfusate significantly increased during reperfusion in the control group but not in the Cytosorb group (P = 0.023, 0.049). Levels of the other cytokines were numerically lower in the Cytosorb group; however, this did not reach statistical significance. The mean renal blood flow (RBF) was significantly higher in the Cytosorb group (162 ± 53 vs. 120 ± 35 mL/min/100 g; P = 0.022). Perfusate levels of prostaglandin E2 were significantly lower in the Cytosorb group (642 ± 762 vs. 3258 ± 980 pg/mL; P = 0.0001). Levels of prostacyclin were significantly lower in the Cytosorb group at 1, 3 and 6 h of reperfusion (P = 0.008, 0.003, 0.0002). Levels of thromboxane were also significantly lower in the Cytosorb group throughout reperfusion (P = 0.005). Haemoadsorption had no effect on creatinine clearance (P = 0.109). Haemoadsorption can reduce the inflammatory response and improve renal blood flow during perfusion. Nonetheless, in this model haemoadsorption had no influence on renal function and this may relate to the broad-spectrum action of the Cytosorb adsorber that also removes potentially important anti

  4. Corona discharge ion mobility spectrometry at reduced pressures

    International Nuclear Information System (INIS)

    Tabrizchi, Mahmoud; Rouholahnejad, Fereshteh

    2004-01-01

    Ion mobility spectrometers (IMSs) normally operate at ambient pressure. In this work an IMS cell has been designed and constructed to allow the pressure to be reduced inside the IMS cell. In this cell, corona discharge was employed as the ionization source. Reducing pressure affected both the discharge and the performance of the IMS. The discharge current was observed to increase with reducing pressure while the ignition potential decreased. The ion current received at the collector plate was also increased about 50 times when the pressure was reduced from ambient pressure to 15 Torr. The higher ion current can lead to an extended dynamic range. IMS spectra were recorded at various pressures and the results show that the drift times shift perfectly linear with pressure. This suggests that unlike temperature, pressure correction for ion mobility spectra is as simple as multiplying the drift times by a factor of 760/P

  5. Reducing maternal mortality: Systolic blood pressure

    African Journals Online (AJOL)

    2006-03-21

    Mar 21, 2006 ... While deaths due to fluid overload have ... of better fluid balance management, we have made .... systolic blood pressure plays a significant role in the .... one looks at the work of Martin et al.5 ... Promoting Healthy Life.

  6. Perfusion Pressure Cerebral Infarct (PPCI) trial - the importance of mean arterial pressure during cardiopulmonary bypass to prevent cerebral complications after cardiac surgery

    DEFF Research Database (Denmark)

    Vedel, Anne G.; Holmgaard, Frederik; Rasmussen, Lars Simon

    2016-01-01

    Background: Debilitating brain injury occurs in 1.6–5 % of patients undergoing cardiac surgery with cardiopulmonary bypass. Diffusion-weighted magnetic resonance imaging studies have reported stroke-like lesions in up to 51 % of patients after cardiac surgery. The majority of the lesions seem...... to be caused by emboli, but inadequate blood flow caused by other mechanisms may increase ischaemia in the penumbra or cause watershed infarcts. During cardiopulmonary bypass, blood pressure can be below the lower limit of cerebral autoregulation. Although much debated, the constant blood flow provided...... by the cardiopulmonary bypass system is still considered by many as appropriate to avoid cerebral ischaemia despite the low blood pressure. Methods/design: The Perfusion Pressure Cerebral Infarct trial is a single-centre superiority trial with a blinded outcome assessment. The trial is randomising 210 patients...

  7. Acute retinal ischemia caused by controlled low ocular perfusion pressure in a porcine model. Electrophysiological and histological characterisation

    DEFF Research Database (Denmark)

    Kyhn, Maria Voss; Warfvinge, Karin; Scherfig, Erik

    2009-01-01

    The purpose of this study was to establish, and characterize a porcine model of acute, controlled retinal ischemia. The controlled retinal ischemia was produced by clamping the ocular perfusion pressure (OPP) in the left eye to 5 mm Hg for 2 h. The OPP was defined as mean arterial blood pressure...... of the amplitudes obtained in the experimental, left eye, and the control, right eye. Quantitative histology was performed to measure the survival of ganglion cells, amacrine cells and horizontal cells 2-6 weeks after the ischemic insult. An OPP of 5 mm Hg for 2h induced significant reductions in the amplitudes...... the ischemic insult. This model seems to be suitable for investigations of therapeutic initiatives in diseases involving acute retinal ischemia....

  8. Time Course of Changes in Extravascular Lung Water Index, Intracranial and Cerebral Perfusion Pressures in Acute Cerebral Circulatory Disorders

    Directory of Open Access Journals (Sweden)

    Yu. A. Churlyaev

    2009-01-01

    Full Text Available Objective: to study the time course of changes in extravascular lung water index (ELWI and intracranial and cerebral perfusion pressures (ICP and CPP and to determine their possible relationships in acute cerebral circulatory disorders (ACCD. Subject and methods. ELWI, pulmonary vascular permeability index (PVPI, ICP, CPP, and central hemodynamics were studied by transpulmonary thermodilution and current X-ray studies were conducted in 18 patients on days 1, 3, 5, and 7 of ACCD. Results. Examinations revealed a supratentorial dislocation of the brain in 6 persons; its subtento-rial dislocation was found in 1 case; supra- and subtentorial dislocations were seen in 6. In patients, ELWI and PVPI increased from days 1 and 5, respectively. The high baseline ICP increased over time. CPP remained unchanged. Preserved left ventricular contractility, enhanced myocardial one, a significant direct correlation between ELWI and PVPI, as well as their increase confirmed that the noncardiogenic genesis was responsible for increased ELWI. A direct significant correlation was found between ICP and ELWI, ICP and PVPI. Against this background, acute respiratory distress syndrome developed in 14 patients with pneumonia evolving in its presence in 7 patients. Conclusion. In ACCD, ELWI increases in the first 24 hours of the acute period. One of its causes is, along with others, primary and/or secondary damage to the brainstem structures with elevated ICP and progressive brain dislocation. The determination of ICP, unlike CPP, is crucial in the diagnosis and treatment of primary/secondary brain injuries and in prognosis. Key words: acute cerebral circulatory disorder, extravascular lung fluid, pulmonary vascular permeability, intracranial pressure, cerebral perfusion pressure, acute respiratory distress syndrome.

  9. Evaluation of a breath-motion-correction technique in reducing measurement error in hepatic CT perfusion imaging

    International Nuclear Information System (INIS)

    He Wei; Liu Jianyu; Li Xuan; Li Jianying; Liao Jingmin

    2009-01-01

    Objective: To evaluate the effect of a breath-motion-correction (BMC) technique in reducing measurement error of the time-density curve (TDC) in hepatic CT perfusion imaging. Methods: Twenty-five patients with suspected liver diseases underwent hepatic CT perfusion scans. The right branch of portal vein was selected as the anatomy of interest and performed BMC to realign image slices for the TDC according to the rule of minimizing the temporal changes of overall structures. Ten ROIs was selected on the right branch of portal vein to generate 10 TDCs each with and without BMC. The values of peak enhancement and the time-to-peak enhancement for each TDC were measured. The coefficients of variation (CV) of peak enhancement and the time-to-peak enhancement were calculated for each patient with and without BMC. Wilcoxon signed ranks test was used to evaluate the difference between the CV of the two parameters obtained with and without BMC. Independent-samples t test was used to evaluate the difference between the values of peak enhancement obtained with and without BMC. Results: The median (quartiles) of CV of peak enhancement with BMC [2.84% (2.10%, 4.57%)] was significantly lower than that without BMC [5.19% (3.90%, 7.27%)] (Z=-3.108,P<0.01). The median (quartiles) of CV of time-to-peak enhancement with BMC [2.64% (0.76%, 4.41%)] was significantly lower than that without BMC [5.23% (3.81%, 7.43%)] (Z=-3.924, P<0.01). In 8 cases, TDC demonstrated statistically significant higher peak enhancement with BMC (P<0.05). Conclusion: By applying the BMC technique we can effectively reduce measurement error for parameters of the TDC in hepatic CT perfusion imaging. (authors)

  10. Increased blood pressure can reduce fatigue of thenar muscles paralyzed after spinal cord injury

    NARCIS (Netherlands)

    Butler, JE; Ribot-Ciscar, E; Zijdewind, Inge; Thomas, CK

    The aim of this study was to evaluate whether increases in blood pressure, and presumably muscle perfusion pressure, improve the endurance of thenar muscles paralyzed chronically by cervical spinal cord injury (SCI). Resting mean arterial pressure (MAP) was low in all eight subjects (64 +/- 2 mmHg).

  11. Air Circulation and Heat Exchange Under Reduced Pressures

    Science.gov (United States)

    Rygalov, V.; Wheeler, R.; Dixon, M.; Fowler, P.; Hillhouse, L.

    2010-01-01

    Heat exchange rates decrease non-linearly with reductions in atmospheric pressure. This decrease creates risk of thermal stress (elevated leaf temperatures) for plants under reduced pressures. Forced convection (fans) significantly increases heat exchange rate under almost all pressures except below 10 kPa. Plant cultivation techniques under reduced pressures will require forced convection. The cooling curve technique is a reliable means of assessing the influence of environmental variables like pressure and gravity on gas exchange of plant. These results represent the extremes of gas exchange conditions for simple systems under variable pressures. In reality, dense plant canopies will exhibit responses in between these extremes. More research is needed to understand the dependence of forced convection on atmospheric pressure. The overall thermal balance model should include latent and radiative exchange components.

  12. Acute volume expansion attenuates hyperthermia-induced reductions in cerebral perfusion during simulated hemorrhage

    DEFF Research Database (Denmark)

    Schlader, Zachary J; Seifert, Thomas; Wilson, Thad E

    2013-01-01

    Hyperthermia reduces the capacity to withstand a simulated hemorrhagic challenge, but volume loading preserves this capacity. This study tested the hypotheses that acute volume expansion during hyperthermia increases cerebral perfusion and attenuates reductions in cerebral perfusion during...... infusion while hyperthermic. Primary dependent variables were mean middle cerebral artery blood velocity (MCAvmean), serving as an index of cerebral perfusion; mean arterial pressure (MAP); and cardiac output (thermodilution). During baseline, hyperthermia reduced MCAvmean (P = 0.001) by 12 ± 9% relative...

  13. Importance of pressure reducing valves (PRVs) in water supply networks.

    Science.gov (United States)

    Signoreti, R. O. S.; Camargo, R. Z.; Canno, L. M.; Pires, M. S. G.; Ribeiro, L. C. L. J.

    2016-08-01

    Challenged with the high rate of leakage from water supply systems, these managers are committed to identify control mechanisms. In order to standardize and control the pressure Pressure Reducing Valves (VRP) are installed in the supply network, shown to be more effective and provide a faster return for the actual loss control measures. It is known that the control pressure is while controlling the occurrence of leakage. Usually the network is sectored in areas defined by pressure levels according to its topography, once inserted the VRP in the same system will limit the downstream pressure. This work aims to show the importance of VRP as loss reduction for tool.

  14. Comparison of Optic Nerve Head Blood Flow Autoregulation among Quadrants Induced by Decreased Ocular Perfusion Pressure during Vitrectomy

    Directory of Open Access Journals (Sweden)

    Ryuya Hashimoto

    2017-01-01

    Full Text Available Purpose. The present study aimed to examine changes in optic nerve head (ONH blood flow autoregulation in 4 quadrants (superior, nasal, inferior, and temporal with decreased ocular perfusion pressure (OPP during vitrectomy in order to determine whether there is a significant difference of autoregulatory capacity in response to OPP decrease at each ONH quadrant. Methods. This study included 24 eyes with an epiretinal membrane or macular hole that underwent vitrectomy at Toho University Sakura Medical Center. Following vitrectomy, the tissue mean blur rate (MBR, which reflects ONH blood flow, was measured. Mean tissue MBRs in the four quadrants were generated automatically in the software analysis report. Measurements were conducted before and 5 and 10 min after intraocular pressure (IOP elevation of approximately 15 mmHg in the subjects without systemic disorders. Results. The baseline tissue MBR of the temporal quadrant was significantly lower than that of the other 3 quadrants (all P<0.05. However, the time courses of tissue MBR in response to OPP decrease were not significantly different among the four quadrants during vitrectomy (P=0.23. Conclusions. There is no significant difference in the autoregulatory capacity of the four ONH quadrants in patients without systemic disorders during vitrectomy.

  15. Reducing body fat with altitude hypoxia training in swimmers: role of blood perfusion to skeletal muscles.

    Science.gov (United States)

    Chia, Michael; Liao, Chin-An; Huang, Chih-Yang; Lee, Wen-Chih; Hou, Chien-Wen; Yu, Szu-Hsien; Harris, M Brennan; Hsu, Tung-Shiung; Lee, Shin-Da; Kuo, Chia-Hua

    2013-02-28

    Swimmers tend to have greater body fat than athletes from other sports. The purpose of the study was to examine changes in body composition after altitude hypoxia exposure and the role of blood distribution to the skeletal muscle in swimmers. With a constant training volume of 12.3 km/day, young male swimmers (N = 10, 14.8 ± 0.5 years) moved from sea-level to a higher altitude of 2,300 meters. Body composition was measured before and after translocation to altitude using dual-energy X-ray absorptiometry (DXA) along with 8 control male subjects who resided at sea level for the same period of time. To determine the effects of hypoxia on muscle blood perfusion, total hemoglobin concentration (THC) was traced by near-infrared spectroscopy (NIRS) in the triceps and quadriceps muscles under glucose-ingested and insulin-secreted conditions during hypoxia exposure (16% O2) after training. While no change in body composition was found in the control group, subjects who trained at altitude had unequivocally decreased fat mass (-1.7 ± 0.3 kg, -11.4%) with increased lean mass (+0.8 ± 0.2 kg, +1.5%). Arterial oxygen saturation significantly decreased with increased plasma lactate during hypoxia recovery mimicking 2,300 meters at altitude (~93% versus ~97%). Intriguingly, hypoxia resulted in elevated muscle THC, and sympathetic nervous activities occurred in parallel with greater-percent oxygen saturation in both muscle groups. In conclusion, the present study provides evidence that increased blood distribution to the skeletal muscle under postprandial condition may contribute to the reciprocally increased muscle mass and decreased body mass after a 3-week altitude exposure in swimmers.

  16. Hyperventilation, cerebral perfusion, and syncope

    DEFF Research Database (Denmark)

    Immink, R V; Pott, F C; Secher, N H

    2014-01-01

    dioxide (PaCO2) and oxygen (PaO2) partial pressures so that hypercapnia/hypoxia increases and hypocapnia/hyperoxia reduces global cerebral blood flow. Cerebral hypoperfusion and TLOC have been associated with hypocapnia related to HV. Notwithstanding pronounced cerebrovascular effects of PaCO2...... the contribution of a low PaCO2 to the early postural reduction in middle cerebral artery blood velocity is transient. HV together with postural stress does not reduce cerebral perfusion to such an extent that TLOC develops. However when HV is combined with cardiovascular stressors like cold immersion or reduced...... cardiac output brain perfusion becomes jeopardized. Whether, in patients with cardiovascular disease and/or defect, cerebral blood flow cerebral control HV-induced hypocapnia elicits cerebral hypoperfusion, leading to TLOC, remains to be established....

  17. A comparative analysis of the postural and diurnal ocular perfusion pressure of young healthy individuals of different ethnicities

    Directory of Open Access Journals (Sweden)

    Alvin J. Munsamy

    2018-06-01

    Full Text Available Purpose: Ocular perfusion pressure (OPP regulates the flow of blood to the optic nerve and is determined by the interaction between intraocular pressure (IOP and blood pressure (BP. Low OPP increases the incidence of primary open-angle glaucoma (POAG. The aim is to compare the diurnal (i.e. morning vs. afternoon and postural (i.e. seated vs. supine OPP in healthy individuals from different ethnicities aged between 18 and 30 years. Methodology: Averaged IOP and BP measurements were obtained with an ICare rebound tonometer and an automated sphygmomanometer, respectively. Measurements were taken in the morning and afternoon, in the supine and seated positions in healthy young adults: Africans (n = 10, white people (n = 10, mixed-race people (n = 10 and Indians (n = 10. Results: The whole sample (N = 40 displayed a statistically significant reduction in postural and diurnal OPP both in the supine position and in the morning, respectively. A comparative analysis revealed that Africans displayed statistically significant reduction in OPP when compared to other ethnicities. Discussion: A change in posture to the supine position has a greater impact on the reduction of OPP when compared to diurnal changes. Africans displayed clinically significant reduction in OPP which may increase the incidence of POAG in this ethnicity at an early age. Conclusion: Our findings question whether OPP should be considered as a biomarker in the dark-skinned individuals. An evaluation of BP and IOP in the supine position is recommended for all patients to obtain more conclusive readings.

  18. Skin perfusion pressure on the legs measured as the external pressure required for skin reddening after blanching

    DEFF Research Database (Denmark)

    Holstein, P; Nielsen, P.E.; Lund, P

    1980-01-01

    -187) compared to 80.8 mmHg (range 18-158) (P > 0.1). A normal material was obtained from twenty-four subjects measured on the thigh, calf and ankle; the average gradients between the auscultatory brachial mean blood pressure and the BTEP were: thigh 10.7 mmHg (SD 12.7); calf 4.0 mmHg (SD 12.1); ankle 5.1 mm...

  19. Hypothermic oxygenated machine perfusion reduces bile duct reperfusion injury after transplantation of donation after circulatory death livers

    Science.gov (United States)

    van Rijn, Rianne; van Leeuwen, Otto B.; Matton, Alix P. M.; Burlage, Laura C.; Wiersema‐Buist, Janneke; van den Heuvel, Marius C.; de Kleine, Ruben H. J.; de Boer, Marieke T.; Gouw, Annette S. H.

    2018-01-01

    Dual hypothermic oxygenated machine perfusion (DHOPE) of the liver has been advocated as a method to reduce ischemia/reperfusion injury (IRI). This study aimed to determine whether DHOPE reduces IRI of the bile ducts in donation after circulatory death (DCD) liver transplantation. In a recently performed phase 1 trial, 10 DCD livers were preserved with DHOPE after static cold storage (SCS; http://www.trialregister.nl NTR4493). Bile duct biopsies were obtained at the end of SCS (before DHOPE; baseline) and after graft reperfusion in the recipient. Histological severity of biliary injury was graded according to an established semiquantitative grading system. Twenty liver transplantations using DCD livers not preserved with DHOPE served as controls. Baseline characteristics and the degree of bile duct injury at baseline (end of SCS) were similar between both groups. In controls, the degree of stroma necrosis (P = 0.002) and injury of the deep peribiliary glands (PBG; P = 0.02) increased after reperfusion compared with baseline. In contrast, in DHOPE‐preserved livers, the degree of bile duct injury did not increase after reperfusion. Moreover, there was less injury of deep PBG (P = 0.04) after reperfusion in the DHOPE group compared with controls. In conclusion, this study suggests that DHOPE reduces IRI of bile ducts after DCD liver transplantation. Liver Transplantation 24 655–664 2018 AASLD. PMID:29369470

  20. Skin Perfusion Pressure Measurement to Assess Improvement in Peripheral Circulation after Arterial Reconstruction for Critical Limb Ischemia

    Science.gov (United States)

    Watanabe, Yoshiko; Onozuka, Atsuko; Obitsu, Yukio; Komai, Hiroyoshi; Koizumi, Nobusato; Saiki, Naozumi; Shigematsu, Hiroshi

    2011-01-01

    Aim: To assess the utility of skin perfusion pressure (SPP) measurement in evaluating the outcome of vascular constructions for critical limb ischemia (CLI) patients. Methods: We retrospectively studied 19 lower limbs in 18 patients who underwent arterial reconstruction for CLI from whom SPP measurements had been obtained pre- and postoperatively between 2008 and 2010. Six limbs whose ulcers had healed postoperatively were classified into group H, 7 limbs whose ulcers had not healed into group U, and 6 limbs without ulcers into group N. SPP values were compared among these groups. Results: The preoperative SPP values in all groups were <30 mmHg, without significant differences among the groups. The SPP values in groups H and N significantly improved after operation, and those in group U were significantly lower than those in the other groups. Conclusions: SPP measurement before and after arterial reconstruction is useful to assess improvement in tissue circulation and to predict the likelihood of wound healing. An SPP value ≥30 mmHg was considered necessary for wound healing, supporting the findings of the few reports in the literature on the usefulness of SPP for assessing vascular reconstruction effects on ulcer wound healing. PMID:23555459

  1. Increasing preferred step rate during running reduces plantar pressures.

    Science.gov (United States)

    Gerrard, James M; Bonanno, Daniel R

    2018-01-01

    Increasing preferred step rate during running is a commonly used strategy in the management of running-related injuries. This study investigated the effect of different step rates on plantar pressures during running. Thirty-two healthy runners ran at a comfortable speed on a treadmill at five step rates (preferred, ±5%, and ±10%). For each step rate, plantar pressure data were collected using the pedar-X in-shoe system. Compared to running with a preferred step rate, a 10% increase in step rate significantly reduced peak pressure (144.5±46.5 vs 129.3±51 kPa; P=.033) and maximum force (382.3±157.6 vs 334.0±159.8 N; P=.021) at the rearfoot, and reduced maximum force (426.4±130.4 vs 400.0±116.6 N; P=.001) at the midfoot. In contrast, a 10% decrease in step rate significantly increased peak pressure (144.5±46.5 vs 161.5±49.3 kPa; P=.011) and maximum force (382.3±157.6 vs 425.4±155.3 N; P=.032) at the rearfoot. Changing step rate by 5% provided no effect on plantar pressures, and no differences in plantar pressures were observed at the medial forefoot, lateral forefoot or hallux between the step rates. This study's findings indicate that increasing preferred step rate by 10% during running will reduce plantar pressures at the rearfoot and midfoot, while decreasing step rate by 10% will increase plantar pressures at the rearfoot. However, changing preferred step rate by 5% will provide no effect on plantar pressures, and forefoot pressures are unaffected by changes in step rate. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  2. Effect of Hemodialysis on Eye Coats, Axial Length, and Ocular Perfusion Pressure in Patients with Chronic Renal Failure

    Directory of Open Access Journals (Sweden)

    Ling Wang

    2018-01-01

    Full Text Available Purpose. To investigate changes in eye coats, axial length, and ocular perfusion pressure (OPP in hemodialysis (HD patients with chronic renal failure (CRF. Methods. We included HD patients who were diagnosed with CRF in our hospital from January to December 2015. Fifty-two patients met the inclusion criteria; all right eyes were used for observation. Systolic and diastolic blood pressures were recorded to calculate OPP. Approximately 30 minutes before and after HD, we recorded multiple parameters, including lens thickness (LT, axial length of vitreous (VAL, axial length of eye (EAL, ciliary body thickness (CBT, choroidal thickness (CT, and retinal thickness (RT. Results. After HD, OPP significantly decreased (P<0.01, F=7.023 and CBT became significantly thinner (P<0.01, t=3.461. CT was significantly thinner and differed among measurement locations (P<0.01, t=6.240; P<0.01, t=6.169; P<0.01, t=3.405, respectively, fovea, nasal, and temporal side 1500 μm beside the fovea. Further, RT thickened and differed among measurement locations (P<0.05, t=−2.265; P<0.05, t=−2.624; P<0.05, t=−2.220, respectively, fovea, nasal, and temporal side 1500 μm beside fovea, whereas LT, VAL, and EAL significantly increased after HD (P<0.05, t=−2.076; P<0.01, t=−3.817; P<0.01, t=−4.010. Conclusions. HD impacts the thickness of the eye coats and VAL, particularly affecting CBT, CT, and RT. OPP transiently decreases during HD, which may contribute to an ischemic state.

  3. Skin peripheral perfusion pressure (SPPP) in the leg using a technique of 133Xe clearance method

    International Nuclear Information System (INIS)

    Ito, Hidetoshi; Tanaka, Sanae; Shimada, Takao; Isogai, Yukihide; Mori, Yutaka; Kawakami, Kenji

    1990-01-01

    We developed a new technique for measuring skin peripheral pressure (SPPP) in the leg by 133 Xe clearance method and studied the SPPP in 50 normal volunteers and 86 diabetic patients, including 16 diabetics with gangrene. The SPPP in normal subjects, diabetics without gangrene and diabetics with gangrene were 41.9±8.6 cmH 2 O, 30.2±12.7 cmH 2 O and 19.4±10.3 cmH 2 O, respectively. Our result revealed that the SPPP in diabetics with gangrene was significantly lowest in three groups. The decrease of the SPPP in the diabetics may be due to the steal phenomenon of the blood flow through the abnormally dilated arteriovenous shunt vessels caused by the diabetic neuropathy. The measurement of the SPPP is very useful to assess the impairment of peripheral circulation. (author)

  4. Van der Waals pressure sensors using reduced graphene oxide composites

    Science.gov (United States)

    Jung, Ju Ra; Ahn, Sung Il

    2018-04-01

    Reduced graphene oxide (RGO) films intercalated with various polymers were fabricated by reaction-based self-assembly, and their characteristics as vacuum pressure sensors based on van der Waals interactions were studied. At low temperature, the electrical resistances of the samples decrease linearly with increasing vacuum pressure, whereas at high temperature the variation of the electrical resistance shows secondary order curves. Among all samples, the poly vinyl alcohol intercalated RGO shows the highest sensitivity, being almost two times more sensitive than reference RGO. All samples show almost the same signal for repetitive sudden pressure changes, indicating reasonable reproducibility and durability.

  5. Air Circulation and Heat Exchange under Reduced Pressures

    Science.gov (United States)

    Rygalov, Vadim; Wheeler, Raymond; Dixon, Mike; Hillhouse, Len; Fowler, Philip

    Low pressure atmospheres were suggested for Space Greenhouses (SG) design to minimize sys-tem construction and re-supply materials, as well as system manufacturing and deployment costs. But rarified atmospheres modify heat exchange mechanisms what finally leads to alter-ations in thermal control for low pressure closed environments. Under low atmospheric pressures (e.g., lower than 25 kPa compare to 101.3 kPa for normal Earth atmosphere), convection is becoming replaced by diffusion and rate of heat exchange reduces significantly. During a period from 2001 to 2009, a series of hypobaric experiments were conducted at Space Life Sciences Lab (SLSLab) NASA's Kennedy Space Center and the Department of Space Studies, University of North Dakota. Findings from these experiments showed: -air circulation rate decreases non-linearly with lowering of total atmospheric pressure; -heat exchange slows down with pressure decrease creating risk of thermal stress (elevated leaf tem-peratures) for plants in closed environments; -low pressure-induced thermal stress could be reduced by either lowering system temperature set point or increasing forced convection rates (circulation fan power) within certain limits; Air circulation is an important constituent of controlled environments and plays crucial role in material and heat exchange. Theoretical schematics and mathematical models are developed from a series of observations. These models can be used to establish optimal control algorithms for low pressure environments, such as a space greenhouse, as well as assist in fundamental design concept developments for these or similar habitable structures.

  6. Myocardial kinetics of thallium-201 after stress in normal and perfusion-reduced canine myocardium

    International Nuclear Information System (INIS)

    Okada, R.D.

    1985-01-01

    Despite the emerging use of quantitative computer programs for assessing myocardial thallium uptake and clearance after exercise, little is known about the kinetics of thallium after exercise stress. Accordingly, 11 mongrel dogs with experimental left anterior descending coronary stenoses were given thallium during norepinephrine infusion to simulate exercise. The infusion was discontinued and thallium activity was monitored regionally using miniature radiation detectors for 3 hours. Heart rate, arterial pressure and double product all increased significantly during norepinephrine infusion. The mean fractional myocardial thallium clearance was lower (0.47 +/- 0.03 [+/- standard error of the mean]) for the stenosis zone than for the no-stenosis zone (0.57 +/- 0.03) (p less than 0.0001). The stress blood flow ratio (stenosis/no-stenosis zone = 0.27 +/- 0.06) was significantly lower than the final thallium activity ratio (0.68 +/- 0.07) (p less than 0.001), consistent with thallium redistribution occurring over the 3-hour period. Myocardial thallium activity in the stenosis zone peaked in a mean of 2.2 minutes, then washed out biexponentially with a final decay constant of 0.0035 +/- 0.0005 min-1. Myocardial thallium activity in the no-stenosis zone peaked within 1 minute in all dogs, then washed out biexponentially, with a final decay constant of 0.0043 +/- 0.0003 (p less than 0.001 compared with stenosis zone). In conclusion, fractional clearance of thallium can differentiate myocardium distal to a coronary artery stenosis from that supplied by a normal coronary vessel

  7. High-Dose, Single-Fraction Irradiation Rapidly Reduces Tumor Vasculature and Perfusion in a Xenograft Model of Neuroblastoma

    Energy Technology Data Exchange (ETDEWEB)

    Jani, Ashish; Shaikh, Fauzia; Barton, Sunjay [Department of Radiation Oncology, Columbia University Medical Center, New York, New York (United States); Willis, Callen [Department of Surgery, Columbia University Medical Center, New York, New York (United States); Banerjee, Debarshi [Department of Pediatrics, Columbia University Medical Center, New York, New York (United States); Mitchell, Jason [Department of Surgery, Columbia University Medical Center, New York, New York (United States); Hernandez, Sonia L. [Department of Surgery, University of Chicago, Chicago, Illinois (United States); Hei, Tom [Department of Radiation Oncology, Columbia University Medical Center, New York, New York (United States); Kadenhe-Chiweshe, Angela [Department of Surgery, Columbia University Medical Center, New York, New York (United States); Yamashiro, Darrell J. [Department of Surgery, Columbia University Medical Center, New York, New York (United States); Department of Pediatrics, Columbia University Medical Center, New York, New York (United States); Department of Pathology and Cell Biology, Columbia University Medical Center, New York, New York (United States); Connolly, Eileen P., E-mail: epc2116@cumc.columbia.edu [Department of Radiation Oncology, Columbia University Medical Center, New York, New York (United States)

    2016-04-01

    Purpose: To characterize the effects of high-dose radiation therapy (HDRT) on neuroblastoma tumor vasculature, including the endothelial cell (EC)–pericyte interaction as a potential target for combined treatment with antiangiogenic agents. Methods and Materials: The vascular effects of radiation therapy were examined in a xenograft model of high-risk neuroblastoma. In vivo 3-dimensional contrast-enhanced ultrasonography (3D-CEUS) imaging and immunohistochemistry (IHC) were performed. Results: HDRT significantly reduced tumor blood volume 6 hours after irradiation compared with the lower doses used in conventionally fractionated radiation. There was a 63% decrease in tumor blood volume after 12-Gy radiation compared with a 24% decrease after 2 Gy. Analysis of tumor vasculature by lectin angiography showed a significant loss of small vessel ends at 6 hours. IHC revealed a significant loss of ECs at 6 and 72 hours after HDRT, with an accompanying loss of immature and mature pericytes at 72 hours. Conclusions: HDRT affects tumor vasculature in a manner not observed at lower doses. The main observation was an early reduction in tumor perfusion resulting from a reduction of small vessel ends with a corresponding loss of endothelial cells and pericytes.

  8. Does chocolate reduce blood pressure? A meta-analysis

    Directory of Open Access Journals (Sweden)

    Ried Karin

    2010-06-01

    Full Text Available Abstract Background Dark chocolate and flavanol-rich cocoa products have attracted interest as an alternative treatment option for hypertension, a known risk factor for cardiovascular disease. Previous meta-analyses concluded that cocoa-rich foods may reduce blood pressure. Recently, several additional trials have been conducted with conflicting results. Our study summarises current evidence on the effect of flavanol-rich cocoa products on blood pressure in hypertensive and normotensive individuals. Methods We searched Medline, Cochrane and international trial registries between 1955 and 2009 for randomised controlled trials investigating the effect of cocoa as food or drink compared with placebo on systolic and diastolic blood pressure (SBP/DBP for a minimum duration of 2 weeks. We conducted random effects meta-analysis of all studies fitting the inclusion criteria, as well as subgroup analysis by baseline blood pressure (hypertensive/normotensive. Meta-regression analysis explored the association between type of treatment, dosage, duration or baseline blood pressure and blood pressure outcome. Statistical significance was set at P Results Fifteen trial arms of 13 assessed studies met the inclusion criteria. Pooled meta-analysis of all trials revealed a significant blood pressure-reducing effect of cocoa-chocolate compared with control (mean BP change ± SE: SBP: -3.2 ± 1.9 mmHg, P = 0.001; DBP: -2.0 ± 1.3 mmHg, P = 0.003. However, subgroup meta-analysis was significant only for the hypertensive or prehypertensive subgroups (SBP: -5.0 ± 3.0 mmHg; P = 0.0009; DBP: -2.7 ± 2.2 mm Hg, P = 0.01, while BP was not significantly reduced in the normotensive subgroups (SBP: -1.6 ± 2.3 mmHg, P = 0.17; DBP: -1.3 ± 1.6 mmHg, P = 0.12. Nine trials used chocolate containing 50% to 70% cocoa compared with white chocolate or other cocoa-free controls, while six trials compared high- with low-flavanol cocoa products. Daily flavanol dosages ranged from 30

  9. Energy-Recovery Pressure-Reducer in District Heating System

    Directory of Open Access Journals (Sweden)

    Dariusz Borkowski

    2018-06-01

    Full Text Available Already existing man-made infrastructures that create water flow and unused pressure are interesting energy sources to which micro-hydropower plants can be applied. Apart from water supply systems (WSSs, which are widely described in the literature, significant hydropower potential can also be found in district heating systems (DHSs. In this paper, a prototype, a so-called energy-recovery pressure-reducer (ERPR, utilized for a DHS, is presented. It consisted of a pump as a turbine coupled to a permanent magnet synchronous generator (PMSG. The latter was connected to the power grid through the power electronic unit (PEU. The variable-speed operation allowed one to modify the turbine characteristics to match the substation’s hydraulic conditions. The proposed ERPR device could be installed in series to the existing classic pressure reducing valve (PRV as an independent device that reduces costs and simplifies system installation. The test results of the prototype system located in a substation of Cracow’s DHS are presented. The steady-state curves and regulation characteristics show the prototype’s operating range and efficiency. In this study, the pressure-reducer impact on the electrical and hydraulic systems, and on the environment, were analyzed. The operation tests during the annual heating season revealed an average system’s efficiency of 49%.

  10. Microcirculatory Imaging in Cardiac Anesthesia: Ketanserin Reduces Blood Pressure But Not Perfused Capillary Density

    NARCIS (Netherlands)

    Elbers, Paul W. G.; Ozdemir, Alaattin; van Iterson, Mat; van Dongen, Eric P. A.; Ince, Can

    2009-01-01

    Objectives: It has become possible to image the human microcirculation at the bedside using sidestream dark field (SDF) imaging. This may help the clinician when correlation between global and microvascular hemodynamics may not be straightforward. Ketanserin, a serotonin and alpha-1 adrenoceptor

  11. Does chocolate reduce blood pressure? A meta-analysis.

    Science.gov (United States)

    Ried, Karin; Sullivan, Thomas; Fakler, Peter; Frank, Oliver R; Stocks, Nigel P

    2010-06-28

    Dark chocolate and flavanol-rich cocoa products have attracted interest as an alternative treatment option for hypertension, a known risk factor for cardiovascular disease. Previous meta-analyses concluded that cocoa-rich foods may reduce blood pressure. Recently, several additional trials have been conducted with conflicting results. Our study summarises current evidence on the effect of flavanol-rich cocoa products on blood pressure in hypertensive and normotensive individuals. We searched Medline, Cochrane and international trial registries between 1955 and 2009 for randomised controlled trials investigating the effect of cocoa as food or drink compared with placebo on systolic and diastolic blood pressure (SBP/DBP) for a minimum duration of 2 weeks. We conducted random effects meta-analysis of all studies fitting the inclusion criteria, as well as subgroup analysis by baseline blood pressure (hypertensive/normotensive). Meta-regression analysis explored the association between type of treatment, dosage, duration or baseline blood pressure and blood pressure outcome. Statistical significance was set at P chocolate compared with control (mean BP change +/- SE: SBP: -3.2 +/- 1.9 mmHg, P = 0.001; DBP: -2.0 +/- 1.3 mmHg, P = 0.003). However, subgroup meta-analysis was significant only for the hypertensive or prehypertensive subgroups (SBP: -5.0 +/- 3.0 mmHg; P = 0.0009; DBP: -2.7 +/- 2.2 mm Hg, P = 0.01), while BP was not significantly reduced in the normotensive subgroups (SBP: -1.6 +/- 2.3 mmHg, P = 0.17; DBP: -1.3 +/- 1.6 mmHg, P = 0.12). Nine trials used chocolate containing 50% to 70% cocoa compared with white chocolate or other cocoa-free controls, while six trials compared high- with low-flavanol cocoa products. Daily flavanol dosages ranged from 30 mg to 1000 mg in the active treatment groups, and interventions ran for 2 to 18 weeks. Meta-regression analysis found study design and type of control to be borderline significant but possibly indirect predictors

  12. Evaluation of an isotope washout technique to measure skin vascular resistance and skin perfusion pressure: influence of age, site and arterial surgery

    International Nuclear Information System (INIS)

    Duncan, H.J.; Faris, I.B.

    1986-01-01

    1. A simplified isotope (sup(99m)Tc) washout technique has been devised to calculate the skin perfusion pressure (SPP) and skin vascular resistance (SVR). This test is simple, requires inexpensive equipment and is well tolerated by patients. 2. SPP and SVR were calculated in 20 patients 30 years of age and in 15 patients with peripheral vascular disease (PVD). With increasing age the SPP and SVP were increased. The SPP was similar to the mean arterial pressure in normal individuals but was decreased in patients with PVD. The SPP is a useful indicator of the severity of the PVD. 3. The SPP and SVR were higher in the calf than in the foot. This is probably related to the decrease in pressure in the distal arterial tree. 4. SPP was increased by 110% and skin blood flow by 190% by arterial reconstructive surgery. This test may be of use in assessing the effectiveness of arterial surgery. (author)

  13. Reducing uncertainty in geostatistical description with well testing pressure data

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, A.C.; He, Nanqun [Univ. of Tulsa, OK (United States); Oliver, D.S. [Chevron Petroleum Technology Company, La Habra, CA (United States)

    1997-08-01

    Geostatistics has proven to be an effective tool for generating realizations of reservoir properties conditioned to static data, e.g., core and log data and geologic knowledge. Due to the lack of closely spaced data in the lateral directions, there will be significant variability in reservoir descriptions generated by geostatistical simulation, i.e., significant uncertainty in the reservoir descriptions. In past work, we have presented procedures based on inverse problem theory for generating reservoir descriptions (rock property fields) conditioned to pressure data and geostatistical information represented as prior means for log-permeability and porosity and variograms. Although we have shown that the incorporation of pressure data reduces the uncertainty below the level contained in the geostatistical model based only on static information (the prior model), our previous results assumed did not explicitly account for uncertainties in the prior means and the parameters defining the variogram model. In this work, we investigate how pressure data can help detect errors in the prior means. If errors in the prior means are large and are not taken into account, realizations conditioned to pressure data represent incorrect samples of the a posteriori probability density function for the rock property fields, whereas, if the uncertainty in the prior mean is incorporated properly into the model, one obtains realistic realizations of the rock property fields.

  14. Subnormothermic ex vivo liver perfusion reduces endothelial cell and bile duct injury after donation after cardiac death pig liver transplantation.

    Science.gov (United States)

    Knaak, Jan M; Spetzler, Vinzent N; Goldaracena, Nicolas; Boehnert, Markus U; Bazerbachi, Fateh; Louis, Kristine S; Adeyi, Oyedele A; Minkovich, Leonid; Yip, Paul M; Keshavjee, Shaf; Levy, Gary A; Grant, David R; Selzner, Nazia; Selzner, Markus

    2014-11-01

    An ischemic-type biliary stricture (ITBS) is a common feature after liver transplantation using donation after cardiac death (DCD) grafts. We compared sequential subnormothermic ex vivo liver perfusion (SNEVLP; 33°C) with cold storage (CS) for the prevention of ITBS in DCD liver grafts in pig liver transplantation (n = 5 for each group). Liver grafts were stored for 10 hours at 4°C (CS) or preserved with combined 7-hour CS and 3-hour SNEVLP. Parameters of hepatocyte [aspartate aminotransferase (AST), international normalized ratio (INR), factor V, and caspase 3 immunohistochemistry], endothelial cell (EC; CD31 immunohistochemistry and hyaluronic acid), and biliary injury and function [alkaline phosphatase (ALP), total bilirubin, and bile lactate dehydrogenase (LDH)] were determined. Long-term survival (7 days) after transplantation was similar between the SNEVLP and CS groups (60% versus 40%, P = 0.13). No difference was observed between SNEVLP- and CS-treated animals with respect to the peak of serum INR, factor V, or AST levels within 24 hours. CD31 staining 8 hours after transplantation demonstrated intact EC lining in SNEVLP-treated livers (7.3 × 10(-4) ± 2.6 × 10(-4) cells/μm(2)) but not in CS-treated livers (3.7 × 10(-4) ± 1.3 × 10(-4) cells/μm(2) , P = 0.03). Posttransplant SNEVLP animals had decreased serum ALP and serum bilirubin levels in comparison with CS animals. In addition, LDH in bile fluid was lower in SNEVLP pigs versus CS pigs (14 ± 10 versus 60 ± 18 μmol/L, P = 0.02). Bile duct histology revealed severe bile duct necrosis in 3 of 5 animals in the CS group but none in the SNEVLP group (P = 0.03). Sequential SNEVLP preservation of DCD grafts reduces bile duct and EC injury after liver transplantation. © 2014 American Association for the Study of Liver Diseases.

  15. Skin perfusion pressure measured with a photo sensor in an air-filled plastic balloon: validity and reproducibility on the lower leg in normal subjects and patients suspected of obliterative arterial disease

    DEFF Research Database (Denmark)

    Nielsen, Steen Levin; Nielsen, Anne Lerberg; Vind, Susanne Haase

    2011-01-01

    An inflatable small plastic bag including a photo sensor was constructed for measurement of skin perfusion pressure avoiding the rim of the photo sensor over bony and tendineous surfaces of the tibia below the knee, at the ankle, and on the dorsal forefoot. Compression was obtained using a conical...... blood pressure cuff with continuous decrease from suprasystolic arm pressure. The validity of skin perfusion pressure with the new device was compared to that of isotope washout below the knee in normal subjects and in patients with an ischemic forefoot with acceptable agreement. The method had a high...... reproducibility within and between days in normal subjects. Compared to systolic arterial pressure measured using a strain gauge with a cuff on the ankle in normal subjects and patients with intermittent claudication the new device showed blood pressure in the skin closer to the diastolic pressure. The new...

  16. Simple motion correction strategy reduces respiratory-induced motion artifacts for k-t accelerated and compressed-sensing cardiovascular magnetic resonance perfusion imaging.

    Science.gov (United States)

    Zhou, Ruixi; Huang, Wei; Yang, Yang; Chen, Xiao; Weller, Daniel S; Kramer, Christopher M; Kozerke, Sebastian; Salerno, Michael

    2018-02-01

    Cardiovascular magnetic resonance (CMR) stress perfusion imaging provides important diagnostic and prognostic information in coronary artery disease (CAD). Current clinical sequences have limited temporal and/or spatial resolution, and incomplete heart coverage. Techniques such as k-t principal component analysis (PCA) or k-t sparcity and low rank structure (SLR), which rely on the high degree of spatiotemporal correlation in first-pass perfusion data, can significantly accelerate image acquisition mitigating these problems. However, in the presence of respiratory motion, these techniques can suffer from significant degradation of image quality. A number of techniques based on non-rigid registration have been developed. However, to first approximation, breathing motion predominantly results in rigid motion of the heart. To this end, a simple robust motion correction strategy is proposed for k-t accelerated and compressed sensing (CS) perfusion imaging. A simple respiratory motion compensation (MC) strategy for k-t accelerated and compressed-sensing CMR perfusion imaging to selectively correct respiratory motion of the heart was implemented based on linear k-space phase shifts derived from rigid motion registration of a region-of-interest (ROI) encompassing the heart. A variable density Poisson disk acquisition strategy was used to minimize coherent aliasing in the presence of respiratory motion, and images were reconstructed using k-t PCA and k-t SLR with or without motion correction. The strategy was evaluated in a CMR-extended cardiac torso digital (XCAT) phantom and in prospectively acquired first-pass perfusion studies in 12 subjects undergoing clinically ordered CMR studies. Phantom studies were assessed using the Structural Similarity Index (SSIM) and Root Mean Square Error (RMSE). In patient studies, image quality was scored in a blinded fashion by two experienced cardiologists. In the phantom experiments, images reconstructed with the MC strategy had higher

  17. Influence of antihypertensive therapy on cerebral perfusion in patients with metabolic syndrome: relationship with cognitive function and 24-h arterial blood pressure monitoring.

    Science.gov (United States)

    Efimova, Nataliya Y; Chernov, Vladimir I; Efimova, Irina Y; Lishmanov, Yuri B

    2015-08-01

    To investigate the regional cerebral blood flow, cognitive function, and parameters of 24-h arterial blood pressure monitoring in patients with metabolic syndrome before and after combination antihypertensive therapy. The study involved 54 patients with metabolic syndrome (MetS) investigated by brain single-photon emission computed tomography, 24-h blood pressure monitoring (ABPM), and comprehensive neuropsychological testing before and after 24 weeks of combination antihypertensive therapy. Patients with metabolic syndrome had significantly poorer regional cerebral blood flow compared with control group: by 7% (P = 0.003) in right anterior parietal cortex, by 6% (P = 0.028) in left anterior parietal cortex, by 8% (P = 0.007) in right superior frontal lobe, and by 10% (P = 0.00002) and 7% (P = 0.006) in right and left temporal brain regions, correspondingly. The results of neuropsychological testing showed 11% decrease in mentation (P = 0.002), and 19% (P = 0.011) and 20% (P = 0.009) decrease in immediate verbal and visual memory in patients with MetS as compared with control group. Relationships between the indices of ABPM, cerebral perfusion, and cognitive function were found. Data showed an improvement of regional cerebral blood flow, ABPM parameters, and indicators of cognitive functions after 6 months of antihypertensive therapy in patients with MetS. The study showed the presence of diffuse disturbances in cerebral perfusion is associated with cognitive disorders in patients with metabolic syndrome. Combination antihypertensive treatment exerts beneficial effects on the 24-h blood pressure profile, increases cerebral blood flow, and improves cognitive function in patients with MetS. © 2015 John Wiley & Sons Ltd.

  18. Skin perfusion pressure measured with a photo sensor in an air-filled plastic balloon: validity and reproducibility on the lower leg in normal subjects and patients suspected of obliterative arterial disease

    International Nuclear Information System (INIS)

    Nielsen, Steen Levin; Nielsen, Anne Lerberg; Vind, Susanne Haase; Thomassen, Anders

    2011-01-01

    An inflatable small plastic bag including a photo sensor was constructed for measurement of skin perfusion pressure avoiding the rim of the photo sensor over bony and tendineous surfaces of the tibia below the knee, at the ankle, and on the dorsal forefoot. Compression was obtained using a conical blood pressure cuff with continuous decrease from suprasystolic arm pressure. The validity of skin perfusion pressure with the new device was compared to that of isotope washout below the knee in normal subjects and in patients with an ischemic forefoot with acceptable agreement. The method had a high reproducibility within and between days in normal subjects. Compared to systolic arterial pressure measured using a strain gauge with a cuff on the ankle in normal subjects and patients with intermittent claudication the new device showed blood pressure in the skin closer to the diastolic pressure. The new pressure device thus had acceptable validity and reproducibility for estimation of the skin perfusion pressure and can be used on bony and tendineous sites on the lower limb in regions where critical wound healing is frequent, e.g. ankle and forefoot

  19. Renal perfusion scintiscan

    Science.gov (United States)

    ... Radionuclide renal perfusion scan; Perfusion scintiscan - renal; Scintiscan - renal perfusion Images Kidney anatomy Kidney - blood and urine flow Intravenous pyelogram References Rottenberg G, Andi AC. Renal ...

  20. Coronary perfusion pressure and compression quality in maternal cardiopulmonary resuscitation in supine and left-lateral tilt positions: A prospective, crossover study using mannequins and swine models.

    Science.gov (United States)

    Dohi, Satoshi; Ichizuka, Kiyotake; Matsuoka, Ryu; Seo, Kohei; Nagatsuka, Masaaki; Sekizawa, Akihiko

    2017-09-01

    The risk of maternal and fetal mortality is high if cardiopulmonary arrest occurs during pregnancy. To assess the best position for maternal cardiopulmonary resuscitation (CPR), a prospective randomized crossover study was undertaken, involving basic life support mannequin-based simulation (BLS-MS) and a swine model of pulseless electrical activity (an unstable cardiac state) incorporating a fetal mannequin (PEA-FM). The BLS-MS (performed by certified rescuers) served to evaluate the quality of chest compressions in 30° left lateral tilt (LLT) and supine positions. Based on a 5-point scale, each rescuer subjectively graded their experience. The PEA-FM model was used to compare coronary perfusion pressure readings during CPR in supine, supine with left uterine displacement, 30° LLT, and 30° right lateral tilt positions. Compression rate and correctness of hand position, compression depth, and recoil were measures of compression quality (BLS-MS). Compared with LLT position, supine position enabled correct hand position (rate: 0.99 vs 0.88; p<0.05) and compression depth (rate: 0.76 vs 0.36; p<0.001) significantly more often. Moreover, BLS-MS rescuers found chest compressions significantly easier to perform with the mannequin in supine (vs LLT) position (difficulty score: 1.75 vs 3.95; p<0.001). In the PEA-FM study arm, supine position with left uterine displacement and right lateral tilt positions had the highest and lowest recorded coronary perfusion pressure readings, respectively. Supine position with left uterine displacement is optimal for maternal CPR. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  1. Developing a Customized Perfusion Bioreactor Prototype with Controlled Positional Variability in Oxygen Partial Pressure for Bone and Cartilage Tissue Engineering.

    Science.gov (United States)

    Lee, Poh Soo; Eckert, Hagen; Hess, Ricarda; Gelinsky, Michael; Rancourt, Derrick; Krawetz, Roman; Cuniberti, Gianaurelio; Scharnweber, Dieter

    2017-05-01

    Skeletal development is a multistep process that involves the complex interplay of multiple cell types at different stages of development. Besides biochemical and physical cues, oxygen tension also plays a pivotal role in influencing cell fate during skeletal development. At physiological conditions, bone cells generally reside in a relatively oxygenated environment whereas chondrocytes reside in a hypoxic environment. However, it is technically challenging to achieve such defined, yet diverse oxygen distribution on traditional in vitro cultivation platforms. Instead, engineered osteochondral constructs are commonly cultivated in a homogeneous, stable environment. In this study, we describe a customized perfusion bioreactor having stable positional variability in oxygen tension at defined regions. Further, engineered collagen constructs were coaxed into adopting the shape and dimensions of defined cultivation platforms that were precasted in 1.5% agarose bedding. After cultivating murine embryonic stem cells that were embedded in collagen constructs for 50 days, mineralized constructs of specific dimensions and a stable structural integrity were achieved. The end-products, specifically constructs cultivated without chondroitin sulfate A (CSA), showed a significant increase in mechanical stiffness compared with their initial gel-like constructs. More importantly, the localization of osteochondral cell types was specific and corresponded to the oxygen tension gradient generated in the bioreactor. In addition, CSA in complementary with low oxygen tension was also found to be a potent inducer of chondrogenesis in this system. In summary, we have demonstrated a customized perfusion bioreactor prototype that is capable of generating a more dynamic, yet specific cultivation environment that could support propagation of multiple osteochondral lineages within a single engineered construct in vitro. Our system opens up new possibilities for in vitro research on human

  2. A Retrospective study of Pressure ulcers in critically ill patients in a ...

    African Journals Online (AJOL)

    A Retrospective study of Pressure ulcers in critically ill patients in a ... reduced tissue perfusion, neurologic deficits, faecal or urinary incontinence. This study determined the prevalence and risk factors for the development of pressure ulcer in ...

  3. Effects of dexamethasone and cox inhibitors on intracranial pressure and cerebral perfusion in the lipopolysaccharide treated rats with hyperammonemia

    DEFF Research Database (Denmark)

    Rohde, Johan; Pedersen, Hans; Bjerring, Peter N

    2015-01-01

    INTRODUCTION: Systemic inflammation may affect the brain by aggravating the stage of encephalopathy and increasing intracranial pressure (ICP) especially if liver insufficiency with hyperammonemia is present. The aim of this study was to determine if the influence of concomitant hyperammonemia...

  4. [An automatic system controlled by microcontroller for carotid sinus perfusion].

    Science.gov (United States)

    Yi, X L; Wang, M Y; Fan, Z Z; He, R R

    2001-08-01

    To establish a new method for controlling automatically the carotid perfusion pressure. A cheap practical automatic perfusion unit based on AT89C2051 micro controller was designed. The unit, LDB-M perfusion pump and the carotid sinus of an animal constituted an automatic perfusion system. This system was able to provide ramp and stepwise updown perfusion pattern and has been used in the research of baroreflex. It can insure the precision and reproducibility of perfusion pressure curve, and improve the technical level in corresponding medical field.

  5. Enhancing Documentation of Pressure Ulcer Prevention Interventions: A Quality Improvement Strategy to Reduce Pressure Ulcers.

    Science.gov (United States)

    Jacobson, Therese M; Thompson, Susan L; Halvorson, Anna M; Zeitler, Kristine

    2016-01-01

    Prevention of hospital-acquired pressure ulcers requires the implementation of evidence-based interventions. A quality improvement project was conducted to provide nurses with data on the frequency with which pressure ulcer prevention interventions were performed as measured by documentation. Documentation reports provided feedback to stakeholders, triggering reminders and reeducation. Intervention reports and modifications to the documentation system were effective both in increasing the documentation of pressure ulcer prevention interventions and in decreasing the number of avoidable hospital-acquired pressure ulcers.

  6. A potential to reduce pulmonary toxicity: The use of perfusion SPECT with IMRT for functional lung avoidance in radiotherapy of non-small cell lung cancer

    International Nuclear Information System (INIS)

    Lavrenkov, Konstantin; Christian, Judith A.; Partridge, Mike; Niotsikou, Elena; Cook, Gary; Parker, Michelle; Bedford, James L.; Brada, Michael

    2007-01-01

    Background and purpose: The study aimed to examine specific avoidance of functional lung (FL) defined by a single photon emission computerized tomography (SPECT) lung perfusion scan, using intensity modulated radiotherapy (IMRT) and three-dimensional conformal radiotherapy (3-DCRT) in patients with non-small cell lung cancer (NSCLC). Materials and methods: Patients with NSCLC underwent planning computerized tomography (CT) and lung perfusion SPECT scan in the treatment position using fiducial markers to allow co-registration in the treatment planning system. Radiotherapy (RT) volumes were delineated on the CT scan. FL was defined using co-registered SPECT images. Two inverse coplanar RT plans were generated for each patient: 4-field 3-DCRT and 5-field step-and-shoot IMRT. 3-DCRT plans were created using automated AutoPlan optimisation software, and IMRT plans were generated employing Pinnacle 3 treatment planning system (Philips Radiation Oncology Systems). All plans were prescribed to 64 Gy in 32 fractions using data for the 6 MV beam from an Elekta linear accelerator. The objectives for both plans were to minimize the volume of FL irradiated to 20 Gy (fV 20 ) and dose variation within the planning target volume (PTV). A spinal cord dose was constrained to 46 Gy. Volume of PTV receiving 90% of the prescribed dose (PTV 90 ), fV 20 , and functional mean lung dose (fMLD) were recorded. The PTV 90 /fV 20 ratio was used to account for variations in both measures, where a higher value represented a better plan. Results: Thirty-four RT plans of 17 patients with stage I-IIIB NSCLC suitable for radical RT were analysed. In 6 patients with stage I-II disease there was no improvement in PTV 90 , fV 20 , PTV/fV 20 ratio and fMLD using IMRT compared to 3-DCRT. In 11 patients with stage IIIA-B disease, the PTV was equally well covered with IMRT and 3-DCRT plans, with IMRT producing better PTV 90 /fV 20 ratio (mean ratio - 7.2 vs. 5.3, respectively, p = 0.001) and reduced f

  7. Reduced Lung Cancer Mortality With Lower Atmospheric Pressure.

    Science.gov (United States)

    Merrill, Ray M; Frutos, Aaron

    2018-01-01

    Research has shown that higher altitude is associated with lower risk of lung cancer and improved survival among patients. The current study assessed the influence of county-level atmospheric pressure (a measure reflecting both altitude and temperature) on age-adjusted lung cancer mortality rates in the contiguous United States, with 2 forms of spatial regression. Ordinary least squares regression and geographically weighted regression models were used to evaluate the impact of climate and other selected variables on lung cancer mortality, based on 2974 counties. Atmospheric pressure was significantly positively associated with lung cancer mortality, after controlling for sunlight, precipitation, PM2.5 (µg/m 3 ), current smoker, and other selected variables. Positive county-level β coefficient estimates ( P atmospheric pressure were observed throughout the United States, higher in the eastern half of the country. The spatial regression models showed that atmospheric pressure is positively associated with age-adjusted lung cancer mortality rates, after controlling for other selected variables.

  8. Does Improvised Waterbed Reduce the Incidence of Pressure ...

    African Journals Online (AJOL)

    Jul‑Dec 2015 | Volume 21 | Issue 2. Address for ... There is little evidence that using a pressure ulcer risk scale is better than clinical judgment.[4]. In our center ... plastic bags, with each plastic bag containing exactly 20 sealed sachets of water.

  9. Methods and means for reducing pressure in systems for fire fighting and water spraying in mines

    Energy Technology Data Exchange (ETDEWEB)

    Kozlyuk, A I; Grin' , G V; Yushchenko, Yu N

    1986-01-01

    Valves are evaluated used in water systems for fire fighting and dust suppression in underground black coal mines in the USSR. Specifications of the KR-2, the KR-3 and the R-86 pressure-reducing valves used in deep mines are analyzed. The valves are characterized by low reliability, low capacity and low pressure reducing range. Therefore groups (parallel arrangement) of pressure-reducing valves are used. Using valve groups increases equipment cost. The pressure-reducing systems should consist of no more than 2 valves. The VNIIGD Institute developed the RKGD pressure-reducing valve with the following specifications: inlet pressure 6.87 MPa, outlet pressure from 0.98 to 2.45 MPa, water discharge 100 m/sup 3//h). The RKGD valves are characterized by high reliability but extremely high weight. Therefore, the VNIIGD Institute developed a modified version of pressure-reducing valve, called the PRK (with maximum inlet pressure of 5 MPa, outlet pressure ranging from 0.5 to 1.5 MPa, water discharge 80 m/sup 3//h and weighing 5 kg). Design of the PRK pressure-reducing valve is shown.

  10. Rationale and Design of the Reduce Elevated Left Atrial Pressure in Patients With Heart Failure (Reduce LAP-HF) Trial

    DEFF Research Database (Denmark)

    Hasenfuss, Gerd; Gustafsson, Finn; Kaye, David

    2015-01-01

    OBJECTIVE: Heart failure with preserved ejection fraction (HFpEF) is characterized by elevated left atrial pressure during rest and/or exercise. The Reduce LAP-HF (Reduce Elevated Left Atrial Pressure in Patients With Heart Failure) trial will evaluate the safety and performance of the Interatrial...... Shunt Device (IASD) System II, designed to directly reduce elevated left atrial pressure, in patients with HFpEF. METHODS: The Reduce LAP-HF Trial is a prospective, nonrandomized, open-label trial to evaluate a novel device that creates a small permanent shunt at the level of the atria. A minimum of 60...... patients with ejection fraction ≥40% and New York Heart Association functional class III or IV heart failure with a pulmonary capillary wedge pressure (PCWP) ≥15 mm Hg at rest or ≥25 mm Hg during supine bike exercise will be implanted with an IASD System II, and followed for 6 months to assess the primary...

  11. Pulmonary artery perfusion versus no pulmonary perfusion during cardiopulmonary bypass in patients with COPD

    DEFF Research Database (Denmark)

    Buggeskov, Katrine B; Sundskard, Martin M; Jonassen, Thomas

    2016-01-01

    INTRODUCTION: Absence of pulmonary perfusion during cardiopulmonary bypass (CPB) may be associated with reduced postoperative oxygenation. Effects of active pulmonary artery perfusion were explored in patients with chronic obstructive pulmonary disease (COPD) undergoing cardiac surgery. METHODS: 90...... perfusion with normothermic oxygenated blood during cardiopulmonary bypass appears to improve postoperative oxygenation in patients with COPD undergoing cardiac surgery. Pulmonary artery perfusion with hypothermic HTK solution does not seem to improve postoperative oxygenation. TRIAL REGISTRATION NUMBER...

  12. Liver perfusion scintigraphy prior to and after transjugular intrahepatic portosystemic shunts (TIPS) in patients with portal hypertension

    International Nuclear Information System (INIS)

    Willkomm, P.; Schomburg, A.; Reichmann, K.; Bangard, M.; Overbeck, B.; Biersack, H.J.; Brensing, K.A.; Sauerbruch, T.

    2000-01-01

    Purpose: This investigation was performed to compare the hemodynamic results of the transjugular intrahepatic portosystemic shunt, a new interventional treatment for portal hypertension, with those observed after the established surgical shunt interventions. Methods: We examined 22 patients with portal hypertension due to liver cirrhosis before and after elective TIPS by liver perfusion scintigraphy. The relative portal perfusion was determined before and after the shunt procedure. Additionally, we measured the portal pressure gradient (PPG: Portal-central venous pressure, mmHg). Results: Prior to TIPS, the relative portal perfusion was significantly reduced to 22±9.1%. After the intervention we calculated values of 23.1±10.7% in the TIPS-group (p=0.67; not significant). In spite of unchanged portal perfusion, the portal pressure was significantly (p [de

  13. Work Turbochargers under Reduced Pressure in the Suction Pipe

    Directory of Open Access Journals (Sweden)

    I. V. Filippov

    2014-01-01

    Full Text Available In case consumers have a significant need in the compressed air, the use of turbochargers is a promising direction. The turbocharger operation is largely defined by its running conditions, namely parameters of the intake air and cooling conditions.The paper presents the results of experimental studies of turbochargers type 4CI 425MX4 of series "CENTAC" manufactured by INGERSOL-RAND, which were performed under industrial conditions in a mountainous area with difficult climatic conditions. There were, essentially, no researches of running turbochargers in mountainous areas. The combination of low atmospheric pressure, high temperature of intake air, and specific cooling conditions causes abnormal mode of turbocharger operation. The results of theoretical studies of such modes are found only in N.M. Barannikov’s work while there is no mentioned empirical research at all.Experimental studies were conducted under industrial conditions in the form of passive experiment. All measurements were carried out using a standard measuring system included in the system of compressor monitor and control. During the experimental studies temperature regimes at the turbocharger stage were controlled, and turbocharger pressure ratio and weight output were determined.The results of the research can be formulated as follows:- highland conditions and seasonal variations of atmospheric air have a negative impact on the operation of the turbochargers;- specific work value as an indicator of the economical efficiency exceeds that of the nameplate by 12...21 % depending on the climatic conditions.The problem of functioning normalization of the turbochargers seems to be relevant not only for the considered type of compressor, but also for that of the less power. It is proposed to consider two ways:- installation of the fifth additional stage;- mechanical pressurization in the suction pipe by means of blowers of high power.To make final decision it is necessary to conduct

  14. Skin peripheral perfusion pressure (SPPP) in the leg using a technique of sup 133 Xe clearance method

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Hidetoshi; Tanaka, Sanae; Shimada, Takao; Isogai, Yukihide; Mori, Yutaka; Kawakami, Kenji (Jikei Univ., Tokyo (Japan). School of Medicine)

    1990-10-01

    We developed a new technique for measuring skin peripheral pressure (SPPP) in the leg by {sup 133}Xe clearance method and studied the SPPP in 50 normal volunteers and 86 diabetic patients, including 16 diabetics with gangrene. The SPPP in normal subjects, diabetics without gangrene and diabetics with gangrene were 41.9{plus minus}8.6 cmH{sub 2}O, 30.2{plus minus}12.7 cmH{sub 2}O and 19.4{plus minus}10.3 cmH{sub 2}O, respectively. Our result revealed that the SPPP in diabetics with gangrene was significantly lowest in three groups. The decrease of the SPPP in the diabetics may be due to the steal phenomenon of the blood flow through the abnormally dilated arteriovenous shunt vessels caused by the diabetic neuropathy. The measurement of the SPPP is very useful to assess the impairment of peripheral circulation. (author).

  15. Viscoelastic properties of doped-ceria under reduced oxygen partial pressure

    DEFF Research Database (Denmark)

    Teocoli, Francesca; Esposito, Vincenzo

    2014-01-01

    The viscoelastic properties of gadolinium-doped ceria (CGO) powder compacts are characterized during sintering and cooling under reduced oxygen partial pressure and compared with conventional sintering in air. Highly defective doped ceria in reducing conditions shows peculiar viscoelastic...

  16. Noise reducing screen devices for in-flow pressure sensors

    Science.gov (United States)

    Schmitz, Fredric (Inventor); Liu, Sandy (Inventor); Jaeger, Stephen (Inventor); Horne, W. Clifton (Inventor)

    1997-01-01

    An acoustic sensor assembly is provided for sensing acoustic signals in a moving fluid such as high speed fluid stream. The assembly includes one or more acoustic sensors and a porous, acoustically transparent screen supported between the moving fluid stream and the sensor and having a major surface disposed so as to be tangent to the moving fluid. A layer of reduced velocity fluid separating the sensor from the porous screen. This reduced velocity fluid can comprise substantially still air. A foam filler material attenuates acoustic signals arriving at the assembly from other than a predetermined range of incident angles.

  17. Electronic SSKIN pathway: reducing device-related pressure ulcers.

    Science.gov (United States)

    Campbell, Natalie

    2016-08-11

    This article describes how an interprofessional project in a London NHS Foundation Trust was undertaken to develop an intranet-based medical device-related pressure ulcer prevention and management pathway for clinical staff working across an adult critical care directorate, where life-threatening events require interventions using medical devices. The aim of this project was to improve working policies and processes to define key prevention strategies and provide clinicians with a clear, standardised approach to risk and skin assessment, equipment use, documentation and reporting clinical data using the Trust's CareVue (electronic medical records), Datix (incident reporting and risk-management tool) and eTRACE (online clinical protocol ordering) systems. The process included the development, trial and local implementation of the pathway using collaborative teamwork and the SSKIN care bundle tool. The experience of identifying issues, overcoming challenges, defining best practice and cascading SSKIN awareness training is shared.

  18. Perfusion CT in acute stroke

    International Nuclear Information System (INIS)

    Eckert, Bernd; Roether, Joachim; Fiehler, Jens; Thomalla, Goetz

    2015-01-01

    Modern multislice CT scanners enable multimodal protocols including non-enhanced CT, CT angiography, and CT perfusion. A 64-slice CT scanner provides 4-cm coverage. To cover the whole brain, a 128 - 256-slice scanner is needed. The use of perfusion CT requires an optimized scan protocol in order to reduce exposure to radiation. As compared to non-enhanced CT and CT angiography, the use of CT perfusion increases detection rates of cerebral ischemia, especially small cortical ischemic lesions, while the detection of lacunar and infratentorial stroke lesions remains limited. Perfusion CT enables estimation of collateral flow in acute occlusion of large intra- or extracranial arteries. Currently, no established reliable thresholds are available for determining infarct core and penumbral tissue by CT perfusion. Moreover, perfusion parameters depend on the processing algorithms and the software used for calculation. However, a number of studies point towards a reduction of cerebral blood volume (CBV) below 2 ml/100 g as a critical threshold that identifies infarct core. Large CBV lesions are associated with poor outcome even in the context of recanalization. The extent of early ischemic signs on non-enhanced CT remains the main parameter from CT imaging to guide acute reperfusion treatment. Nevertheless, perfusion CT increases diagnostic and therapeutic certainty in the acute setting. Similar to stroke MRI, perfusion CT enables the identification of tissue at risk of infarction by the mismatch between infarct core and the larger area of critical hypoperfusion. Further insights into the validity of perfusion parameters are expected from ongoing trials of mechanical thrombectomy in stroke.

  19. Voxel-based analysis of Tc-99 m ECD brain perfusion SPECT in patients with normal pressure hydrocephalus

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Bora [Department of Neurology, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Yang, Dong-Won [Department of Neurology, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of)], E-mail: neuroman@catholic.ac.kr; Shim, Yong-Soo; Chung, Sung-Woo [Department of Neurology, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Ahn, Kook-Jin; O, Joo-Hyun; Kim, Sung-Hoon; Sohn, Hyung-Sun; Chung, Soo-Kyo [Department of Radiology, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of); Chung, Yong-An [Department of Radiology, College of Medicine, Catholic University of Korea, Seoul 137-701 (Korea, Republic of); East-West Research Institute of Translational Medicine (EWTM), Incheon St. Mary' s Hospital, Incheon 403-720 (Korea, Republic of)], E-mail: nm@catholic.ac.kr

    2009-07-15

    Idiopathic normal pressure hydrocephalus (iNPH) is a reversible dementia characterized by gait disturbance, incontinence and dementia. This study investigates the neuropsychological characteristics and changes of regional cerebral blood flow (rCBF) in patients with iNPH. Ten patients who met the criteria of probable iNPH and 13 normal control subjects were evaluated. The general cognitive function and detailed neuropsychological functions were measured by K-MMSE and comprehensive neuropsychological battery. Tc-99m-ethyl cysteinate dimmer (Tc-99m-ECD) single photon emission computed tomography (SPECT) was performed to measure the rCBF and statistical parametric mapping (SPM) and statistical probabilistic brain anatomic map (SPAM) was applied to the objective analysis of SPECT data. On the neuropsychological examination, all the patients showed abnormality in memory, psychomotor speed and frontal executive function. SPM analysis of SPECT images revealed that rCBF in bilateral thalami, right prefrontal area, bilateral anterior and posterior cingulate gyri, right caudate nucleus, and left parahippocampal gyrus was significantly decreased in patients with iNPH compared to normal controls (uncorrected P<0.005). In SPAM analysis, rCBF reduction was observed in bilateral prefrontal area, anterior, posterior cingulate gyri and caudate nuclei. We have found that rCBF changes occurred predominantly in prefrontal and subcortical areas, the changes were associated with frontal subcortical circuit, and the affected frontal subcortical circuit may contribute to the cognitive decline seen in the iNPH patients. The reduction of rCBF and clinical cognitive impairment are closely connected in patients with iNPH.

  20. Voxel-based analysis of Tc-99 m ECD brain perfusion SPECT in patients with normal pressure hydrocephalus

    International Nuclear Information System (INIS)

    Yoon, Bora; Yang, Dong-Won; Shim, Yong-Soo; Chung, Sung-Woo; Ahn, Kook-Jin; O, Joo-Hyun; Kim, Sung-Hoon; Sohn, Hyung-Sun; Chung, Soo-Kyo; Chung, Yong-An

    2009-01-01

    Idiopathic normal pressure hydrocephalus (iNPH) is a reversible dementia characterized by gait disturbance, incontinence and dementia. This study investigates the neuropsychological characteristics and changes of regional cerebral blood flow (rCBF) in patients with iNPH. Ten patients who met the criteria of probable iNPH and 13 normal control subjects were evaluated. The general cognitive function and detailed neuropsychological functions were measured by K-MMSE and comprehensive neuropsychological battery. Tc-99m-ethyl cysteinate dimmer (Tc-99m-ECD) single photon emission computed tomography (SPECT) was performed to measure the rCBF and statistical parametric mapping (SPM) and statistical probabilistic brain anatomic map (SPAM) was applied to the objective analysis of SPECT data. On the neuropsychological examination, all the patients showed abnormality in memory, psychomotor speed and frontal executive function. SPM analysis of SPECT images revealed that rCBF in bilateral thalami, right prefrontal area, bilateral anterior and posterior cingulate gyri, right caudate nucleus, and left parahippocampal gyrus was significantly decreased in patients with iNPH compared to normal controls (uncorrected P<0.005). In SPAM analysis, rCBF reduction was observed in bilateral prefrontal area, anterior, posterior cingulate gyri and caudate nuclei. We have found that rCBF changes occurred predominantly in prefrontal and subcortical areas, the changes were associated with frontal subcortical circuit, and the affected frontal subcortical circuit may contribute to the cognitive decline seen in the iNPH patients. The reduction of rCBF and clinical cognitive impairment are closely connected in patients with iNPH.

  1. The effect of dexmedetomidine on cerebral perfusion and oxygenation in healthy piglets with normal and lowered blood pressure anaesthetized with propofol-remifentanil total intravenous anaesthesia

    DEFF Research Database (Denmark)

    Mikkelsen, Mai Louise Grandsgaard; Ambrus, Rikard; Rasmussen, Rune

    2017-01-01

    Background During anaesthesia and surgery, in particular neurosurgery, preservation of cerebral perfusion and oxygenation (CPO) is essential for normal postoperative brain function. The isolated effects on CPO of either individual anaesthetic drugs or entire anaesthetic protocols are of importance...

  2. High protein flexibility and reduced hydration water dynamics are key pressure adaptive strategies in prokaryotes

    KAUST Repository

    Martinez, N.

    2016-09-06

    Water and protein dynamics on a nanometer scale were measured by quasi-elastic neutron scattering in the piezophile archaeon Thermococcus barophilus and the closely related pressure-sensitive Thermococcus kodakarensis, at 0.1 and 40 MPa. We show that cells of the pressure sensitive organism exhibit higher intrinsic stability. Both the hydration water dynamics and the fast protein and lipid dynamics are reduced under pressure. In contrast, the proteome of T. barophilus is more pressure sensitive than that of T. kodakarensis. The diffusion coefficient of hydration water is reduced, while the fast protein and lipid dynamics are slightly enhanced with increasing pressure. These findings show that the coupling between hydration water and cellular constituents might not be simply a master-slave relationship. We propose that the high flexibility of the T. barophilus proteome associated with reduced hydration water may be the keys to the molecular adaptation of the cells to high hydrostatic pressure.

  3. High protein flexibility and reduced hydration water dynamics are key pressure adaptive strategies in prokaryotes

    KAUST Repository

    Martinez, N.; Michoud, Gregoire; Cario, A.; Ollivier, J.; Franzetti, B.; Jebbar, M.; Oger, P.; Peters, J.

    2016-01-01

    Water and protein dynamics on a nanometer scale were measured by quasi-elastic neutron scattering in the piezophile archaeon Thermococcus barophilus and the closely related pressure-sensitive Thermococcus kodakarensis, at 0.1 and 40 MPa. We show that cells of the pressure sensitive organism exhibit higher intrinsic stability. Both the hydration water dynamics and the fast protein and lipid dynamics are reduced under pressure. In contrast, the proteome of T. barophilus is more pressure sensitive than that of T. kodakarensis. The diffusion coefficient of hydration water is reduced, while the fast protein and lipid dynamics are slightly enhanced with increasing pressure. These findings show that the coupling between hydration water and cellular constituents might not be simply a master-slave relationship. We propose that the high flexibility of the T. barophilus proteome associated with reduced hydration water may be the keys to the molecular adaptation of the cells to high hydrostatic pressure.

  4. Application of a stir-tank bioreactor for perfusion culture and ...

    African Journals Online (AJOL)

    STORAGESEVER

    2010-01-18

    Jan 18, 2010 ... The bioreactor we used could be an efficient cell culture system and demonstrates industrial potential. ... overcoming the harmful effects of browning have no conclusive .... solvent under reduced pressure, the ethanol extract liquids was re- ... was detected in the exhaust medium with a perfusion rate of more ...

  5. Hypothermic machine perfusion reduces delayed graft function and improves one-year graft survival of kidneys from expanded criteria donors: a meta-analysis.

    Directory of Open Access Journals (Sweden)

    Baoping Jiao

    Full Text Available BACKGROUND: Expanded criteria donors (ECDs are currently accepted as potential sources to increase the donor pool and to provide more chances of kidney transplantation for elderly recipients who would not survive long waiting periods. Hypothermic machine perfusion (HMP is designed to mitigate the deleterious effects of simple cold storage (CS on the quality of preserved organs, particularly when the donor is in a marginal status. METHODS: We compared the transplant outcomes in patients receiving ECD kidneys with either HMP or CS graft preservation. Articles from the MEDLINE, EMBASE and Cochrane Library databases were searched and all studies reporting outcomes from HMP versus CS methods of kidney preservation were included in this meta-analysis. The parameters analyzed included the incidence of delayed graft function (DGF, primary non-function (PNF and one-year graft and patient survival. RESULTS: A total of seven studies qualified for the review, involving 2374 and 8716 kidney grafts with HMP or CS preservation respectively, all from ECD donors. The incidence of delayed graft function (DGF was significantly reduced with an odd ratio(OR of 0.59 (95% CI 0.54-0.66, P<0.001 and one-year graft survival was significantly improved with an OR of 1.12 (95% CI 1.03-1.21, P = 0.005 in HMP preservation compared to CS. However, there was no difference in the incidence of PNF (OR 0.54, 95% CI 0.21-1.40, P = 0.20, and one-year patient survival (OR 0.98, 95% CI 0.94-1.02, P = 0.36 between HMP and CS preservation. CONCLUSIONS: HMP was associated with a reduced incidence of DGF and an with increased one-year graft survival, but it was not associated with the incidence of PNF and one-year patient survival.

  6. Large-Animal Biventricular Working Heart Perfusion System with Low Priming Volume-Comparison between in vivo and ex vivo Cardiac Function.

    Science.gov (United States)

    Abicht, Jan-Michael; Mayr, Tanja Axinja Jelena; Jauch, Judith; Guethoff, Sonja; Buchholz, Stefan; Reichart, Bruno; Bauer, Andreas

    2018-01-01

    Existing large-animal, ex vivo, cardiac perfusion models are restricted in their ability to establish an ischemia/reperfusion condition as seen in cardiac surgery or transplantation. Other working heart systems only challenge one ventricle or require a substantially larger priming volume. We describe a novel biventricular cardiac perfusion system with reduced priming volume. Juvenile pig hearts were cardiopleged, explanted, and reperfused ex vivo after 150 minutes of cold ischemia. Autologous whole blood was used as perfusate (minimal priming volume 350 mL). After 15 minutes of Langendorff perfusion (LM), the system was switched into a biventricular working mode (WM) and studied for 3 hours. During reperfusion, complete unloading of both ventricles and constant-pressure coronary perfusion was achieved. During working mode perfusion, the preload and afterload pressure of both ventricles was controlled within the targeted physiologic range. Functional parameters such as left ventricular work index were reduced in ex vivo working mode (in vivo: 787 ± 186 vs. 1 h WM 498 ± 66 mm Hg·mL/g·min; p  hours while functional and blood parameters are easily accessible. Moreover, because of the minimal priming volume, the novel ex vivo cardiac perfusion circuit allows for autologous perfusion, using the limited amount of blood available from the organ donating animal. Georg Thieme Verlag KG Stuttgart · New York.

  7. Choking under monitoring pressure: being watched by the experimenter reduces executive attention.

    Science.gov (United States)

    Belletier, Clément; Davranche, Karen; Tellier, Idriss S; Dumas, Florence; Vidal, Franck; Hasbroucq, Thierry; Huguet, Pascal

    2015-10-01

    Performing more poorly given one's skill level ("choking") is likely in situations that offer an incentive if a certain outcome is achieved (outcome pressure) or when one is being watched by others-especially when one's performance is being evaluated (monitoring pressure). According to the choking literature, outcome pressure is associated with reduced executive control of attention, whereas monitoring pressure is associated with increased, yet counterproductive, attention to skill processes. Here, we show the first evidence that monitoring pressure-being watched by the experimenter-may lead individuals with higher working memory to choke on a classic measure of executive control-just the task effect thought to result from outcome pressure. Not only does this finding help refine our understanding of the processes underlying choking under monitoring pressure, but it also leads to a new look at classic audience effects, with an important implication for experimental psychology.

  8. Physiologic Evaluation of Ventilation Perfusion Mismatch and Respiratory Mechanics at Different Positive End-expiratory Pressure in Patients Undergoing Protective One-lung Ventilation.

    Science.gov (United States)

    Spadaro, Savino; Grasso, Salvatore; Karbing, Dan Stieper; Fogagnolo, Alberto; Contoli, Marco; Bollini, Giacomo; Ragazzi, Riccardo; Cinnella, Gilda; Verri, Marco; Cavallesco, Narciso Giorgio; Rees, Stephen Edward; Volta, Carlo Alberto

    2018-03-01

    Arterial oxygenation is often impaired during one-lung ventilation, due to both pulmonary shunt and atelectasis. The use of low tidal volume (VT) (5 ml/kg predicted body weight) in the context of a lung-protective approach exacerbates atelectasis. This study sought to determine the combined physiologic effects of positive end-expiratory pressure and low VT during one-lung ventilation. Data from 41 patients studied during general anesthesia for thoracic surgery were collected and analyzed. Shunt fraction, high V/Q and respiratory mechanics were measured at positive end-expiratory pressure 0 cm H2O during bilateral lung ventilation and one-lung ventilation and, subsequently, during one-lung ventilation at 5 or 10 cm H2O of positive end-expiratory pressure. Shunt fraction and high V/Q were measured using variation of inspired oxygen fraction and measurement of respiratory gas concentration and arterial blood gas. The level of positive end-expiratory pressure was applied in random order and maintained for 15 min before measurements. During one-lung ventilation, increasing positive end-expiratory pressure from 0 cm H2O to 5 cm H2O and 10 cm H2O resulted in a shunt fraction decrease of 5% (0 to 11) and 11% (5 to 16), respectively (P ventilation, high positive end-expiratory pressure levels improve pulmonary function without increasing high V/Q and reduce driving pressure.

  9. Reduced local immune response with continuous positive airway pressure during one-lung ventilation for oesophagectomy

    NARCIS (Netherlands)

    Verhage, R. J. J.; Boone, J.; Rijkers, G. T.; Cromheecke, G. J.; Kroese, A. C.; Weijs, T. J.; Borel Rinkes, I. H. M.; van Hillegersberg, R.

    2014-01-01

    Background. Transthoracic oesophagectomy requires prolonged one-lung ventilation causing systemic and local inflammatory responses. Application of continuous positive airway pressure (CPAP) to the collapsed lung potentially reduces pulmonary damage, hypoxia, and consequent inflammation. This

  10. Intravenous clonidine administration and its ability to reduce pulmonary arterial pressure in patients undergoing heart surgery

    Directory of Open Access Journals (Sweden)

    Benedito Barbosa João

    2014-01-01

    Full Text Available Objective: Evaluate the ability of clonidine to reduce pulmonary arterial pressure in patients with pulmonary hypertension undergoing heart surgery, either by reducing the pressure values from the direct measurement of pulmonary arterial pressure or by reducing or eliminating the need for intraoperative dobutamine and nitroprusside. Method: Randomized, double-blind, placebo-controlled, comparative study conducted in 30 patients with pulmonary arterial hypertension type 2 undergoing cardiac surgery. Mean pulmonary arterial pressure and dosage of dobutamine and sodium nitroprusside were assessed four times: before intravenous administration of clonidine (2 μg/kg or placebo (T0, 30 min after tested treatment and before cardiopulmonary bypass (T1, immediately after CPB (T2, 10 min after protamine injection (T3. Results: There were no significant differences regarding mean pulmonary arterial pressure at any time of evaluation. There was no significant difference between groups regarding other variables, such as mean systemic arterial pressure, heart rate, total dose of dobutamine, total dose of sodium nitroprusside, and need for fentanyl. Conclusion: Data analysis from patients included in this study allows us to conclude that intravenous clonidine (2 μg/kg was not able to reduce the mean pulmonary arterial pressure in patients with pulmonary hypertension in group 2 (pulmonary venous hypertension, undergoing heart surgery, or reduce or eliminate the need for intraoperative administration of dobutamine and sodium nitroprusside. Keywords: Clonidine, Pulmonary hypertension, Heart surgery

  11. The Groningen hypothermic liver perfusion pump : Functional evaluation of a new machine perfusion system

    NARCIS (Netherlands)

    van der Plaats, A.; Maathuis, M. H. J.; Hart, N. A. 't; Bellekom, A. A.; Hofker, H. S.; van der Houwen, E. B.; Verkerke, G. J.; Leuvenink, H. G. D.; Verdonck, P.; Ploeg, R. J.; Rakhorst, G.

    2006-01-01

    To improve preservation of donor livers, we have developed a portable hypothermic machine perfusion (HMP) system as an alternative for static cold storage. A prototype of the system was built and evaluated on functionality. Evaluation criteria included 24 h of adequate pressure controlled perfusion,

  12. Intensive Blood Pressure Control Affects Cerebral Blood Flow in Type 2 Diabetes Mellitus Patients

    NARCIS (Netherlands)

    Kim, Yu-Sok; Davis, Shyrin C. A. T.; Truijen, Jasper; Stok, Wim J.; Secher, Niels H.; van Lieshout, Johannes J.

    2011-01-01

    Type 2 diabetes mellitus is associated with microvascular complications, hypertension, and impaired dynamic cerebral autoregulation. Intensive blood pressure (BP) control in hypertensive type 2 diabetic patients reduces their risk of stroke but may affect cerebral perfusion. Systemic hemodynamic

  13. Kupffer cell depletion attenuates leptin-mediated methoxamine-stimulated portal perfusion pressure and thromboxane A2 release in a rodent model of NASH-cirrhosis.

    Science.gov (United States)

    Yang, Ying-Ying; Huang, Yi-Tsau; Tsai, Tung-Hu; Hou, Ming-Chih; Lee, Fa-Yauh; Lee, Shou-Dong; Lin, Han-Chieh

    2012-12-01

    Cirrhotic portal hypertension is characterized by increased hepatic oxidative stress, AA (arachidonic acid)-derived TXA(2) (thromboxane A(2)) release and exaggerated hepatic response to the α-adrenergic agonist MTX (methoxamine). Besides promoting hepatic fibrosis, the role of hyperleptinaemia in the modulation of vascular response in NASH (non-alcoholic steatohepatitis) rat livers remains unknown. The aim of the present study was to explore the possible links between hyperleptinaemia and the disarrangement in the hepatic microcirculation. NASH-cirrhosis with hyperleptinaemia was induced in lean rats by feeding with an HF/MCD (high-fat/methionine-choline-deficient) diet. Portal haemodynamics, various substances, protein and mRNA expression and PUFA (polyunsaturated fatty acid) composition were measured. Finally, the effects of leptin pre-infusion on TXA(2) release and concentration-PPP (portal perfusion pressure) curves in response to MTX were evaluated by simultaneously pre-treatment with the Kupffer cell inactivators GdCl(3) (gadolinium chloride) or EC (encapsulated clodronate), the TXS (TXA(2) synthase) inhibitor furegrelate, the TP receptor (TXA(2) receptor) antagonist SQ29548 and the dual TXS/TP receptor antagonist BM567. In HF/MCD+leptin-lean rats, cirrhosis-induced PPP and MTX hyper-responsiveness were associated with increased hepatic TXA(2) production, TBARS (thiobarbituric acid-reacting substances) levels and the AA (arachidonic acid)/n-3 PUFA ratio, and up-regulation of hepatic leptin, FAS (fatty acid synthase), NADPH oxidase subunits, TXS, TP receptor, TGFβ(1) (transforming growth factor β(1)) proteins and mRNAs. Pre-infusion of leptin significantly enhanced MTX-stimulated PPP elevation and TXA(2) release, which were attenuated by GdCl(3) and EC pre-treatment. Concomitantly pre-incubation with BM567, but not furegrelate or SQ29548, significantly abolished the leptin-enhanced MTX-stimulated increase in PPP in NASH-cirrhotic rats. Hyperleptinaemia

  14. Chemical vapor deposition of hexagonal boron nitride films in the reduced pressure

    International Nuclear Information System (INIS)

    Choi, B.J.

    1999-01-01

    Hexagonal boron nitride (h-BN) films were deposited onto a graphite substrate in reduced pressure by reacting ammonia and boron tribromide at 800--1,200 C. The growth rate of h-BN films was dependent on the substrate temperature and the total pressures. The growth rate increased with increasing the substrate temperature at the pressure of 2 kPa, while it showed a maximum value at the pressures of 4 and 8 kPa. The temperature at which the maximum growth rate occurs decreased with increasing total pressure. With increasing the substrate temperature and total pressure, the apparent grain size increased and the surface morphology showed a rough, cauliflower-like structure

  15. Improved visualization of delayed perfusion in lung MRI

    International Nuclear Information System (INIS)

    Risse, Frank; Eichinger, Monika; Kauczor, Hans-Ulrich; Semmler, Wolfhard; Puderbach, Michael

    2011-01-01

    Introduction: The investigation of pulmonary perfusion by three-dimensional (3D) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was proposed recently. Subtraction images are generated for clinical evaluation, but temporal information is lost and perfusion defects might therefore be masked in this process. The aim of this study is to demonstrate a simple analysis strategy and classification for 3D-DCE-MRI perfusion datasets in the lung without omitting the temporal information. Materials and methods: Pulmonary perfusion measurements were performed in patients with different lung diseases using a 1.5 T MR-scanner with a time-resolved 3D-GRE pulse sequence. 25 3D-volumes were acquired after iv-injection of 0.1 mmol/kg KG Gadolinium-DTPA. Three parameters were determined for each pixel: (1) peak enhancement S n,max normalized to the arterial input function to detect regions of reduced perfusion; (2) time between arterial peak enhancement in the large pulmonary artery and tissue peak enhancement τ to visualize regions with delayed bolus onset; and (3) ratio R = S n,max /τ was calculated to visualize impaired perfusion, irrespectively of whether related to reduced or delayed perfusion. Results: A manual selection of peak perfusion images is not required. Five different types of perfusion can be found: (1) normal perfusion; (2) delayed non-reduced perfusion; (3) reduced non-delayed perfusion; (4) reduced and delayed perfusion; and (5) no perfusion. Types II and IV could not be seen in subtraction images since the temporal information is necessary for this purpose. Conclusions: The analysis strategy in this study allows for a simple and observer-independent visualization and classification of impaired perfusion in dynamic contrast-enhanced pulmonary perfusion MRI by using the temporal information of the datasets.

  16. Switching strategy between HP (high pressure)- and LPEGR (low pressure exhaust gas recirculation) systems for reduced fuel consumption and emissions

    International Nuclear Information System (INIS)

    Luján, José Manuel; Guardiola, Carlos; Pla, Benjamín; Reig, Alberto

    2015-01-01

    EGR (Exhaust gas recirculation) plays a major role in current Diesel internal combustion engines as a cost-effective solution to reduce NO_x emissions. EGR systems will suffer a significant evolution with the introduction of NO_x after-treatment and the proliferation of more complex EGR architectures such as low pressure EGR or dual EGR. In this paper the combination of HPEGR (high pressure EGR) LPEGR (low pressure EGR) is presented as a method to minimise fuel consumption with reduced NO_x emissions. Particularly, the paper proposes to switch between HPEGR and LPEGR architectures depending on the engine operating conditions in order to exploit the potential of both systems. In this sense, given a driving cycle, in the case at hand the NEDC, the proposed strategy seeks the EGR layout to use at each instant of the cycle to minimise the fuel consumption such that NO_x emissions are kept below a certain limit. The experimental results obtained show that combining both EGR systems sequentially along the NEDC allows to keep NO_x emission below a much lower limit with minimum fuel consumption. - Highlights: • The combination of HP–LPEGR reduces the NO_x with a small impact on consumption. • The switching strategy between HP – LPEGR is derived from Optimal Control Theory. • The proposed strategy is validated experimentally.

  17. Automatic Detection of Myocardial Boundaries in MR Cardio Perfusion Images

    NARCIS (Netherlands)

    Spreeuwers, Luuk; Breeuwer, Marcel

    2001-01-01

    Cardiovascular diseases often result in reduced blood perfusion of the myocardium (MC). Recent advances in MR allow fast recordingof contrast enhanced myocardial perfusion scans. For perfusion analysis the myocardial boundaries must be traced. Currently this is done manually. In this paper a method

  18. Phosphorus atomic layer doping in SiGe using reduced pressure chemical vapor deposition

    International Nuclear Information System (INIS)

    Yamamoto, Yuji; Heinemann, Bernd; Murota, Junichi; Tillack, Bernd

    2014-01-01

    Phosphorus (P) atomic layer doping in SiGe is investigated at temperatures between 100 °C to 600 °C using a single wafer reduced pressure chemical vapor deposition system. SiGe(100) surface is exposed to PH 3 at different PH 3 partial pressures by interrupting SiGe growth. The impact of the SiGe buffer/cap growth condition (total pressure/SiGe deposition precursors) on P adsorption, incorporation, and segregation are investigated. In the case of SiH 4 -GeH 4 -H 2 gas system, steeper P spikes due to lower segregation are observed by SiGe cap deposition at atmospheric (ATM) pressure compared with reduced pressure (RP). The steepness of P spike of ∼ 5.7 nm/dec is obtained for ATM pressure without reducing deposition temperature. This result may be due to the shift of equilibrium of P adsorption/desorption to desorption direction by higher H 2 pressure. Using Si 2 H 6 -GeH 4 -H 2 gas system for SiGe cap deposition in RP, lowering the SiGe growth temperature is possible, resulting in higher P incorporation and steeper P profile due to reduced desorption and segregation. In the case of Si 2 H 6 -GeH 4 -H 2 gas system, the P dose could be simulated assuming a Langmuir-type kinetics model. Incorporated P shows high electrical activity, indicating P is adsorbed mostly in lattice position. - Highlights: • Phosphorus (P) atomic layer doping in SiGe (100) is investigated using CVD. • P adsorption is suppressed by the hydrogen termination of Ge surface. • By SiGe cap deposition at atmospheric pressure, P segregation was suppressed. • By using Si 2 H 6 -based SiGe cap, P segregation was also suppressed. • The P adsorption process is self-limited and follows Langmuir-type kinetics model

  19. Charge Accumulation in LDPE and XLPE Conditioned at 80oC under Reduced Pressure

    DEFF Research Database (Denmark)

    Fleming, Robert J.; Henriksen, Mogens; Holbøll, Joachim T.

    1997-01-01

    The effects of thermal conditioning, under reduced pressure, on space accumulation in planar LDPE and XLPE samples under DC stress, have been investigated. The samples were conditioned prior to voltage application by being held at 80oC for 2-3 days in short circuit at rotary pump pressure. Some...... were then cooled to room temperature over a period of at least 6hr, still under rotary pump pressure and in short circuit, while others were cooled to room temperature in less than 1.5hr in the laboratory air. DC fields of 18kV/mm were then applied at room temperature, and space charge accumulation...

  20. Combined non-adaptive light and smell stimuli lowered blood pressure, reduced heart rate and reduced negative affect.

    Science.gov (United States)

    Dong, Shan; Jacob, Tim J C

    2016-03-15

    Bright light therapy has been shown to have a positive impact on seasonal affective disorder (SAD), depression and anxiety. Smell has also has been shown to have effects on mood, stress, anxiety and depression. The objective of this study was to investigate the effect of the combination of light and smell in a non-adaptive cycle. Human subjects were given smell (lemon, lavender or peppermint) and light stimuli in a triangular wave (60scycle) for 15min. Blood pressure and heart rate were monitored before and after each session for 5 consecutive days and a Profile of Mood States (POMS) test was administered before and after the sensory stimulation on days 1, 3 and 5. The light-smell stimulus lowered blood pressure, both systolic and diastolic, and reduced heart rate for all odours compared to control. Of the two sensory stimuli, the odour stimulus contributed most to this effect. The different aromas in the light-smell combinations could be distinguished by their different effects on the mood factors with lemon inducing the greatest mood changes in Dejection-Depression, Anger-Hostility, Tension-Anxiety. In conclusion, combined light and smell stimulation was effective in lowering blood pressure, reducing heart rate and improving mood. The combination was more effective than either smell or light stimuli alone, suggesting that a light-smell combination would be a more robust and efficacious alternative treatment for depression, anxiety and stress. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  1. Reducing the incidence of pressure ulcers in critical care units: a 4-year quality improvement.

    Science.gov (United States)

    Richardson, Annette; Peart, Joanna; Wright, Stephen E; McCullagh, Iain J

    2017-06-01

    Critical care patients often have several risk factors for pressure ulceration and implementing prevention interventions have been shown to decrease risk. We identified a high incidence of pressure ulcers in the four adult critical care units in our organization. Therefore, avoiding pressure ulceration was an important quality priority. We undertook a quality improvement programme aimed at reducing the incidence of pressure ulceration using an evidence-based bundle approach. A bundle of technical and non-technical interventions were implemented supported by clinical leadership on each unit. Important components were evidence appraisals; changes to mattresses; focussed risk assessment alongside mandating patients at very high risk to be repositioned two hourly; and staff training to increase awareness of how to prevent pressure ulcers. Pressure ulcer numbers, incidence and categories were collected continuously and monitored monthly by unit staff. Pressure ulcer rates reduced significantly from 8.08/100 patient admissions to 2.97/100 patient admissions, an overall relative rate reduction of 63% over 4 years. The greatest reduction was seen in the most severe category of pressure ulceration. The average estimated cost saving was £2.6 million (range £2.1-£3.1). A quality improvement programme including technical and non-technical interventions, data feedback to staff and clinical leadership was associated with a sustained reduction in the incidence of pressure ulceration in the critically ill. Strategies used in this programme may be transferable to other critical care units to bring more widespread patient benefit. © The Author 2017. Published by Oxford University Press in association with the International Society for Quality in Health Care. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com

  2. Reducing pressure ulcers in patients with prolonged acute mechanical ventilation: a quasi-experimental study.

    Science.gov (United States)

    Loudet, Cecilia Inés; Marchena, María Cecilia; Maradeo, María Roxana; Fernández, Silvia Laura; Romero, María Victoria; Valenzuela, Graciela Esther; Herrera, Isabel Eustaquia; Ramírez, Martha Teresa; Palomino, Silvia Rojas; Teberobsky, Mariana Virginia; Tumino, Leandro Ismael; González, Ana Laura; Reina, Rosa; Estenssoro, Elisa

    2017-01-01

    To determine the effectiveness of a quality management program in reducing the incidence and severity of pressure ulcers in critical care patients. This was a quasi-experimental, before-and-after study that was conducted in a medical-surgical intensive care unit. Consecutive patients who had received mechanical ventilation for ≥ 96 hours were included. A "Process Improvement" team designed a multifaceted interventional process that consisted of an educational session, a pressure ulcer checklist, a smartphone application for lesion monitoring and decision-making, and a "family prevention bundle". Fifty-five patients were included in Pre-I group, and 69 were included in the Post-I group, and the incidence of pressure ulcers in these groups was 41 (75%) and 37 (54%), respectively. The median time for pressure ulcers to develop was 4.5 [4 - 5] days in the Pre-I group and 9 [6 - 20] days in the Post-I group after admission for each period. The incidence of advanced-grade pressure ulcers was 27 (49%) in the Pre-I group and 7 (10%) in the Post-I group, and finally, the presence of pressure ulcers at discharge was 38 (69%) and 18 (26%), respectively (p pressure ulcers. The duration of mechanical ventilation and the presence of organ failure were positively associated with the development of pressure ulcers, while the multifaceted intervention program acted as a protective factor. A quality program based on both a smartphone application and family participation can reduce the incidence and severity of pressure ulcers in patients on prolonged acute mechanical ventilation.

  3. Scaling of two-phase flow transients using reduced pressure system and simulant fluid

    International Nuclear Information System (INIS)

    Kocamustafaogullari, G.; Ishii, M.

    1987-01-01

    Scaling criteria for a natural circulation loop under single-phase flow conditions are derived. Based on these criteria, practical applications for designing a scaled-down model are considered. Particular emphasis is placed on scaling a test model at reduced pressure levels compared to a prototype and on fluid-to-fluid scaling. The large number of similarty groups which are to be matched between modell and prototype makes the design of a scale model a challenging tasks. The present study demonstrates a new approach to this clasical problen using two-phase flow scaling parameters. It indicates that a real time scaling is not a practical solution and a scaled-down model should have an accelerated (shortened) time scale. An important result is the proposed new scaling methodology for simulating pressure transients. It is obtained by considerung the changes of the fluid property groups which appear within the two-phase similarity parameters and the single-phase to two-phase flow transition prameters. Sample calculations are performed for modeling two-phase flow transients of a high pressure water system by a low-pressure water system or a Freon system. It is shown that modeling is possible for both cases for simulation pressure transients. However, simulation of phase change transitions is not possible by a reduced pressure water system without distortion in either power or time. (orig.)

  4. Double Contact During Drop Impact on a Solid Under Reduced Air Pressure

    KAUST Repository

    Li, Erqiang

    2017-11-20

    Drops impacting on solid surfaces entrap small bubbles under their centers, owing to the lubrication pressure which builds up in the thin intervening air layer. We use ultrahigh-speed interference imaging, at 5 Mfps, to investigate how this air layer changes when the ambient air pressure is reduced below atmospheric. Both the radius and the thickness of the air disc become smaller with reduced air pressure. Furthermore, we find the radial extent of the air disc bifurcates, when the compressibility parameter exceeds similar to 25. This bifurcation is also imprinted onto some of the impacts, as a double contact. In addition to the central air disc inside the first ring contact, this is immediately followed by a second ring contact, which entraps an outer toroidal strip of air, which contracts into a ring of bubbles. We find this occurs in a regime where Navier slip, due to rarefied gas effects, enhances the rate gas can escape from the path of the droplet.

  5. A Sharp-Interface Immersed Boundary Method with Improved Mass Conservation and Reduced Spurious Pressure Oscillations.

    Science.gov (United States)

    Seo, Jung Hee; Mittal, Rajat

    2011-08-10

    A method for reducing the spurious pressure oscillations observed when simulating moving boundary flow problems with sharp-interface immersed boundary methods (IBMs) is proposed. By first identifying the primary cause of these oscillations to be the violation of the geometric conservation law near the immersed boundary, we adopt a cut-cell based approach to strictly enforce geometric conservation. In order to limit the complexity associated with the cut-cell method, the cut-cell based discretization is limited only to the pressure Poisson and velocity correction equations in the fractional-step method and the small-cell problem tackled by introducing a virtual cell-merging technique. The method is shown to retain all the desirable properties of the original finite-difference based IBM while at the same time, reducing pressure oscillations for moving boundaries by roughly an order of magnitude.

  6. Does improvised waterbed reduce the incidence of pressure ulcers in patients with spinal injury?

    Directory of Open Access Journals (Sweden)

    Jude-Kennedy C Emejulu

    2015-01-01

    Full Text Available Background: Pressure ulcers are lesions caused by unrelieved pressure over bony prominences, resulting in damage to underlying tissues. The etiology is multifactorial including prolonged immobility. They usually complicate spinal cord injuries with long periods of bed confinement. The use of bed replacements markedly reduces the incidence of pressure ulcers, but the unaffordability of these replacements in low-income countries has necessitated the need to explore cheaper alternatives. Aim and Objective: The aim of this study was to ascertain whether the use of our cheap and locally improvised waterbeds would reduce the incidence of pressure ulcers in patients on prolonged bed confinement due to spinal injury. Methodology: Over a 16-month period, 51 patients (age range 1-80 years with spinal injuries were managed conservatively in our service using improvised waterbeds in 21 (41.2%, while using the regular hospital bed/foam in 30 (58.8%. Biodata, the time interval between injury and presentation to the hospital, nature of the injury, use of improvised waterbed and development of pressure ulcer, were collected, collated, and analyzed. Statistical significance was calculated with the Chi-square test. Results: Most were males (98%, in the age range of 21-30 years (25.5%, and due to fall from heights (35.3%. Of 21 patients who were managed on improvised waterbeds, 6 (28.6% had pressure ulcers, and of the 30 who did not use the waterbed, 17 (56.7% developed ulcers. The c2 = 3.9381, while P = 0.0472. This difference was statistically significant. Conclusion: The improvised waterbed, which is much cheaper than the standard waterbed, was observed to have significantly reduced the incidence of pressure ulcers among our patients. Nonetheless, further studies would still be needed to confirm this observation.

  7. Local charge transport properties of hydrazine reduced monolayer graphene oxide sheets prepared under pressure condition

    DEFF Research Database (Denmark)

    Ryuzaki, Sou; Meyer, Jakob Abild Stengaard; Petersen, Søren Vermehren

    2014-01-01

    Charge transport properties of chemically reduced graphene oxide (RGO) sheets prepared by treatment with hydrazine were examined using conductive atomic force microscopy. The current-voltage (I-V) characteristics of monolayer RGO sheets prepared under atmospheric pressure followed an exponentially...

  8. TU-G-204-01: BEST IN PHYSICS (IMAGING): Dynamic CT Myocardial Perfusion Measurement and Its Comparison to Fractional Flow Reserve

    Energy Technology Data Exchange (ETDEWEB)

    Ziemer, B; Hubbard, L; Groves, E; Sadeghi, B; Javan, H; Lipinski, J; Molloi, S [University of California, Irvine, CA (United States)

    2015-06-15

    Purpose: To evaluate a first pass analysis (FPA) technique for CT perfusion measurement in a swine animal and its validation using fractional flow reserve (FFR) as a reference standard. Methods: Swine were placed under anesthesia and relevant physiologic parameters were continuously recorded. Intra-coronary adenosine was administered to induce maximum hyperemia. A pressure wire was advanced distal to the first diagonal branch of the left anterior descending (LAD) artery for FFR measurements and a balloon dilation catheter was inserted over the pressure wire into the proximal LAD to create varying levels of stenosis. Images were acquired with a 320-row wide volume CT scanner. Three main coronary perfusion beds were delineated in the myocardium using arteries extracted from CT angiography images using a minimum energy hypothesis. The integrated density in the perfusion bed was used to calculate perfusion using the FPA technique. The perfusion in the LAD bed over a range of stenosis severity was measured. The measured fractional perfusion was compared to FFR and linear regression was performed. Results: The measured fractional perfusion using the FPA technique (P-FPA) and FFR were related as P-FPA = 1.06FFR – 0.06 (r{sup 2} = 0.86). The perfusion measurements were calculated with only three to five total CT volume scans, which drastically reduces the radiation dose as compared with the existing techniques requiring 15–20 volume scans. Conclusion: The measured perfusion using the first pass analysis technique showed good correlation with FFR measurements as a reference standard. The technique for perfusion measurement can potentially make a substantial reduction in radiation dose as compared with the existing techniques.

  9. TU-G-204-01: BEST IN PHYSICS (IMAGING): Dynamic CT Myocardial Perfusion Measurement and Its Comparison to Fractional Flow Reserve

    International Nuclear Information System (INIS)

    Ziemer, B; Hubbard, L; Groves, E; Sadeghi, B; Javan, H; Lipinski, J; Molloi, S

    2015-01-01

    Purpose: To evaluate a first pass analysis (FPA) technique for CT perfusion measurement in a swine animal and its validation using fractional flow reserve (FFR) as a reference standard. Methods: Swine were placed under anesthesia and relevant physiologic parameters were continuously recorded. Intra-coronary adenosine was administered to induce maximum hyperemia. A pressure wire was advanced distal to the first diagonal branch of the left anterior descending (LAD) artery for FFR measurements and a balloon dilation catheter was inserted over the pressure wire into the proximal LAD to create varying levels of stenosis. Images were acquired with a 320-row wide volume CT scanner. Three main coronary perfusion beds were delineated in the myocardium using arteries extracted from CT angiography images using a minimum energy hypothesis. The integrated density in the perfusion bed was used to calculate perfusion using the FPA technique. The perfusion in the LAD bed over a range of stenosis severity was measured. The measured fractional perfusion was compared to FFR and linear regression was performed. Results: The measured fractional perfusion using the FPA technique (P-FPA) and FFR were related as P-FPA = 1.06FFR – 0.06 (r 2 = 0.86). The perfusion measurements were calculated with only three to five total CT volume scans, which drastically reduces the radiation dose as compared with the existing techniques requiring 15–20 volume scans. Conclusion: The measured perfusion using the first pass analysis technique showed good correlation with FFR measurements as a reference standard. The technique for perfusion measurement can potentially make a substantial reduction in radiation dose as compared with the existing techniques

  10. An ex vivo porcine skin model to evaluate pressure-reducing devices of different mechanical properties used for pressure ulcer prevention.

    Science.gov (United States)

    Yeung, Ching-Yan C; Holmes, David F; Thomason, Helen A; Stephenson, Christian; Derby, Brian; Hardman, Matthew J

    2016-11-01

    Pressure ulcers are complex wounds caused by pressure- and shear-induced trauma to skin and underlying tissues. Pressure-reducing devices, such as dressings, have been shown to successfully reduce pressure ulcer incidence, when used in adjunct to pressure ulcer preventative care. While pressure-reducing devices are available in a range of materials, with differing mechanical properties, understanding of how a material's mechanical properties will influence clinical efficacy remains limited. The aim of this study was to establish a standardized ex vivo model to allow comparison of the cell protection potential of two gel-like pressure-reducing devices with differing mechanical properties (elastic moduli of 77 vs. 35 kPa). The devices also displayed differing energy dissipation under compressive loading, and resisted strain differently under constant load in compressive creep tests. To evaluate biological efficacy we employed a new ex vivo porcine skin model, with a confirmed elastic moduli closely matching that of human skin (113 vs. 119 kPa, respectively). Static loads up to 20 kPa were applied to porcine skin ex vivo with subsequent evaluation of pressure-induced cell death and cytokine release. Pressure application alone increased the percentage of epidermal apoptotic cells from less than 2% to over 40%, and increased cellular secretion of the pro-inflammatory cytokine TNF-alpha. Co-application of a pressure-reducing device significantly reduced both cellular apoptosis and cytokine production, protecting against cellular damage. These data reveal new insight into the relationship between mechanical properties of pressure-reducing devices and their biological effects. After appropriate validation of these results in clinical pressure ulcer prevention with all tissue layers present between the bony prominence and external surface, this ex vivo porcine skin model could be widely employed to optimize design and evaluation of devices aimed at reducing pressure

  11. Evaluation of general-purpose collimators against high-resolution collimators with resolution recovery with a view to reducing radiation dose in myocardial perfusion SPECT: A preliminary phantom study.

    Science.gov (United States)

    Armstrong, Ian S; Saint, Kimberley J; Tonge, Christine M; Arumugam, Parthiban

    2017-04-01

    There is a growing focus on reducing radiation dose to patients undergoing myocardial perfusion imaging. This preliminary phantom study aims to evaluate the use of general-purpose collimators with resolution recovery (RR) to allow a reduction in patient radiation dose. Images of a cardiac torso phantom with inferior and anterior wall defects were acquired on a GE Infinia and Siemens Symbia T6 using both high-resolution and general-purpose collimators. Imaging time, a surrogate for administered activity, was reduced between 35% and 40% with general-purpose collimators to match the counts acquired with high-resolution collimators. Images were reconstructed with RR with and without attenuation correction. Two pixel sizes were also investigated. Defect contrast was measured. Defect contrast on general-purpose images was superior or comparable to the high-resolution collimators on both systems despite the reduced imaging time. Infinia general-purpose images required a smaller pixel size to be used to maintain defect contrast, while Symbia T6 general-purpose images did not require a change in pixel size to that used for standard myocardial perfusion SPECT. This study suggests that general-purpose collimators with RR offer a potential for substantial dose reductions while providing similar or better image quality to images acquired using high-resolution collimators.

  12. Water cycle and its management for plant habitats at reduced pressures

    Science.gov (United States)

    Rygalov, Vadim Y.; Fowler, Philip A.; Wheeler, Raymond M.; Bucklin, Ray A.

    2004-01-01

    Experimental and mathematical models were developed for describing and testing temperature and humidity parameters for plant production in bioregenerative life support systems. A factor was included for analyzing systems operating at low (10-101.3 kPa) pressure to reduce gas leakage and structural mass (e.g., inflatable greenhouses for space application). The expected close relationship between temperature and relative humidity was observed, along with the importance of heat exchanger coil temperature and air circulation rate. The presence of plants in closed habitats results in increased water flux through the system. Changes in pressure affect gas diffusion rates and surface boundary layers, and change convective transfer capabilities and water evaporation rates. A consistent observation from studies with plants at reduced pressures is increased evapotranspiration rates, even at constant vapor pressure deficits. This suggests that plant water status is a critical factor for managing low-pressure production systems. The approach suggested should help space mission planners design artificial environments in closed habitats.

  13. Does dysfunction of the autonomic nervous system affect success of renal denervation in reducing blood pressure?

    Science.gov (United States)

    Fricke, Lisa; Petroff, David; Desch, Steffen; Lurz, Philipp; Reinhardt, Sebastian; Sonnabend, Melanie; Classen, Joseph; Baum, Petra

    2017-01-01

    Renal denervation is an interventional approach aiming to reduce high blood pressure. Its efficacy is subject of controversial debate. We analyzed autonomic function in patients undergoing renal denervation to identify responders. A total of 21 patients with treatment-resistant hypertension scheduled for renal denervation were included. Heart rate variability, pupillary function and sympathetic skin response were examined prior to intervention. Before and 1 or 3 months after intervention, 24-h ambulatory blood pressure readings were taken. Patients were stratified according to sympathetic nervous system function. Sympathetic activity was reduced in 12 participants (group 1) and normal or enhanced in nine patients (group 2). The mean of daytime systolic blood pressure decreased in groups 1 and 2 from 168 to 157 mmHg (95% confidence interval for difference, 1-21 mmHg, p = 0.035) and from 166 to 145 mmHg (8-34 mmHg, p = 0.005), respectively. In a linear model, blood pressure reduction was 11.3 mmHg (0.3-22 mmHg) greater in group 2 than in group 1 (p = 0.045). Patients with preexisting reduced activity of the sympathetic nervous system benefited less from renal denervation.

  14. Using the adaptive SMA composite cylinder concept to reduce radial dilation in composite pressure vessels

    Science.gov (United States)

    Paine, Jeffrey S.; Rogers, Craig A.

    1995-05-01

    Composite materials are widely used in the design of pressurized gas and fluid vessels for applications ranging from underground gasoline storage tanks to rocket motors for the space shuttle. In the design of a high pressure composite vessel (Pi > 12 Ksi), thick-wall (R/h short term dilation and long term creep are not problematic for applications requiring only the containment of the pressurized fluid. In applications where metallic liners are required, however, substantial dilation and creep causes plastic yielding which leads to reduced fatigue life. To applications such as a hydraulic accumulator, where a piston is employed to fit and seal the fluid in the composite cylinder, the dilation and creep may allow leakage and pressure loss around the piston. A concept called the adaptive composite cylinder is experimentally presented. Shape memory alloy wire in epoxy resin is wrapped around or within polymer matrix composite cylinders to reduce radial dilation of the cylinder. Experimental results are presented that demonstrate the ability of the SMA wire layers to reduce radial dilation. Results from experimental testing of the recovery stress fatigue response of nitinol shape memory alloy wires is also presented.

  15. Does dysfunction of the autonomic nervous system affect success of renal denervation in reducing blood pressure?

    Directory of Open Access Journals (Sweden)

    Lisa Fricke

    2017-04-01

    Full Text Available Objectives: Renal denervation is an interventional approach aiming to reduce high blood pressure. Its efficacy is subject of controversial debate. We analyzed autonomic function in patients undergoing renal denervation to identify responders. Methods: A total of 21 patients with treatment-resistant hypertension scheduled for renal denervation were included. Heart rate variability, pupillary function and sympathetic skin response were examined prior to intervention. Before and 1 or 3 months after intervention, 24-h ambulatory blood pressure readings were taken. Results: Patients were stratified according to sympathetic nervous system function. Sympathetic activity was reduced in 12 participants (group 1 and normal or enhanced in nine patients (group 2. The mean of daytime systolic blood pressure decreased in groups 1 and 2 from 168 to 157 mmHg (95% confidence interval for difference, 1–21 mmHg, p = 0.035 and from 166 to 145 mmHg (8–34 mmHg, p = 0.005, respectively. In a linear model, blood pressure reduction was 11.3 mmHg (0.3–22 mmHg greater in group 2 than in group 1 (p = 0.045. Conclusion: Patients with preexisting reduced activity of the sympathetic nervous system benefited less from renal denervation.

  16. Energy and exergy analysis of electricity generation from natural gas pressure reducing stations

    International Nuclear Information System (INIS)

    Neseli, Mehmet Alparslan; Ozgener, Onder; Ozgener, Leyla

    2015-01-01

    Highlights: • Forecasting the recoverable energy from natural gas pressure reduction stations. • Electricity generation through pressure reduction stations via turboexpanders. • A thermodynamics analysis of PRS. - Abstract: Electricity generation or power recovery through pressure reduction stations (PRS) for general use has not been realized in Izmir. The main objective of the present study was to do a case study for calculating electricity to be recovered in one natural gas pressure reduction stations in Izmir. It is the first forecasting study to obtain energy from natural gas pressure-reducing stations in Izmir. Energy can be obtained from natural gas PRS with turbo-expanders instead of using throttle valves or regulators from the PRS. The exergy performance of PRS with TE is evaluated in this study. Exergetic efficiencies of the system and components are determined to assess their individual performances. Based upon pressure change and volumetric flow rate, it can be obtained by recovering average estimated installed capacity and annual energy 494.24 kW, 4113.03 MW h, respectively. In terms of estimated installed capacity power and annual energy, the highest level is 764.88 kW, approximately 6365.34 MW h, in Aliaga PRS. Also it can be seen that CO 2 emission factor average value is 295.45 kg/MW h

  17. Skin perfusion pressure measured by isotope washout in legs with arterial occlusive disease. Evaluation of different tracers, comparison to segmental systolic pressure, angiography and transcutaneous oxygen tension and variations during changes in systemic blood pressure

    DEFF Research Database (Denmark)

    Holstein, P; Trap-Jensen, J; Bagger, H

    1983-01-01

    Hg (range 18-98) (P less than 0.02). The average washout constant for the three different tracers were approximately equal and correlated statistically significant with the SPP; (2) In 59 legs with AOD, segmental SPP was compared to segmental systolic blood pressures on the thigh, calf, ankle and first...... digit (strain gauge technique). The two different methods correlated statistically significant at all four levels, but the systolic blood pressures were higher than the SPP in particular in diabetic legs; (3) Angiograms in 35 legs with AOD showed that the SPP on the ankle was only consistently decreased...

  18. Regional myocardial perfusion of cardioplegic solutions

    International Nuclear Information System (INIS)

    Eugene, J.; Lyons, K.P.; Ott, R.A.; Gelezunas, V.L.; Chang, C.W.; Kowall, M.G.; Haiduc, N.J.

    1987-01-01

    We compared the regional myocardial perfusion of blood cardioplegic solution (BCP) and crystalloid cardioplegic solution (CCP) in 14 mongrel dogs. Cardiopulmonary bypass was established at 28 degrees C, and a hydraulic occluder was placed around the proximal left anterior descending (LAD) coronary artery. In group 1 (N = 7) collateral coronary arteries were ligated; in group 2 (N = 7) collateral coronary arteries were left in situ. After the aorta was clamped, BCP and CCP were alternately perfused at 200 ml/min. The occluder was inflated to produce moderate, severe, and critical LAD stenosis, and regional perfusion was measured by xenon-133 washout with the Silicon Avalanche Radiation Detector. BCP infusion produced a consistently higher aortic pressure, but CCP flow was better than BCP flow under all conditions, particularly without coronary collaterals. Regional myocardial perfusion of CCP is superior to BCP

  19. Strength training reduces arterial blood pressure but not sympathetic neural activity in young normotensive subjects

    Science.gov (United States)

    Carter, Jason R.; Ray, Chester A.; Downs, Emily M.; Cooke, William H.

    2003-01-01

    The effects of resistance training on arterial blood pressure and muscle sympathetic nerve activity (MSNA) at rest have not been established. Although endurance training is commonly recommended to lower arterial blood pressure, it is not known whether similar adaptations occur with resistance training. Therefore, we tested the hypothesis that whole body resistance training reduces arterial blood pressure at rest, with concomitant reductions in MSNA. Twelve young [21 +/- 0.3 (SE) yr] subjects underwent a program of whole body resistance training 3 days/wk for 8 wk. Resting arterial blood pressure (n = 12; automated sphygmomanometer) and MSNA (n = 8; peroneal nerve microneurography) were measured during a 5-min period of supine rest before and after exercise training. Thirteen additional young (21 +/- 0.8 yr) subjects served as controls. Resistance training significantly increased one-repetition maximum values in all trained muscle groups (P < 0.001), and it significantly decreased systolic (130 +/- 3 to 121 +/- 2 mmHg; P = 0.01), diastolic (69 +/- 3 to 61 +/- 2 mmHg; P = 0.04), and mean (89 +/- 2 to 81 +/- 2 mmHg; P = 0.01) arterial blood pressures at rest. Resistance training did not affect MSNA or heart rate. Arterial blood pressures and MSNA were unchanged, but heart rate increased after 8 wk of relative inactivity for subjects in the control group (61 +/- 2 to 67 +/- 3 beats/min; P = 0.01). These results indicate that whole body resistance exercise training might decrease the risk for development of cardiovascular disease by lowering arterial blood pressure but that reductions of pressure are not coupled to resistance exercise-induced decreases of sympathetic tone.

  20. Orthogonal optimization of a water hydraulic pilot-operated pressure-reducing valve

    Science.gov (United States)

    Mao, Xuyao; Wu, Chao; Li, Bin; Wu, Di

    2017-12-01

    In order to optimize the comprehensive characteristics of a water hydraulic pilot-operated pressure-reducing valve, numerical orthogonal experimental design was adopted. Six parameters of the valve, containing diameters of damping plugs, volume of spring chamber, half cone angle of main spool, half cone angle of pilot spool, mass of main spool and diameter of main spool, were selected as the orthogonal factors, and each factor has five different levels. An index of flowrate stability, pressure stability and pressure overstrike stability (iFPOS) was used to judge the merit of each orthogonal attempt. Embedded orthogonal process turned up and a final optimal combination of these parameters was obtained after totally 50 numerical orthogonal experiments. iFPOS could be low to a fairly low value which meant that the valve could have much better stabilities. During the optimization, it was also found the diameters of damping plugs and main spool played important roles in stability characteristics of the valve.

  1. Vertical sleeve gastrectomy reduces blood pressure and hypothalamic endoplasmic reticulum stress in mice

    Directory of Open Access Journals (Sweden)

    Anne K. McGavigan

    2017-03-01

    Full Text Available Bariatric surgery, such as vertical sleeve gastrectomy (VSG, causes remarkable improvements in cardiometabolic health, including hypertension remission. However, the mechanisms responsible remain undefined and poorly studied. Therefore, we developed and validated the first murine model of VSG that recapitulates the blood pressure-lowering effect of VSG using gold-standard radiotelemetry technology. We used this model to investigate several potential mechanisms, including body mass, brain endoplasmic reticulum (ER stress signaling and brain inflammatory signaling, which are all critical contributors to the pathogenesis of obesity-associated hypertension. Mice fed on a high-fat diet underwent sham or VSG surgery and radiotelemeter implantation. Sham mice were fed ad libitum or were food restricted to match their body mass to VSG-operated mice to determine the role of body mass in the ability of VSG to lower blood pressure. Blood pressure was then measured in freely moving unstressed mice by radiotelemetry. VSG decreased energy intake, body mass and fat mass. Mean arterial blood pressure (MAP was reduced in VSG-operated mice compared with both sham-operated groups. VSG-induced reductions in MAP were accompanied by a body mass-independent decrease in hypothalamic ER stress, hypothalamic inflammation and sympathetic nervous system tone. Assessment of gut microbial populations revealed VSG-induced increases in the relative abundance of Gammaproteobacteria and Enterococcus, and decreases in Adlercreutzia. These results suggest that VSG reduces blood pressure, but this is only partly due to the reduction in body weight. VSG-induced reductions in blood pressure may be driven by a decrease in hypothalamic ER stress and inflammatory signaling, and shifts in gut microbial populations.

  2. Watermelon extract reduces blood pressure but does not change sympathovagal balance in prehypertensive and hypertensive subjects.

    Science.gov (United States)

    Massa, Nayara Moreira Lacerda; Silva, Alexandre Sérgio; Toscano, Luciana Tavares; Silva, Joanna D'arc Gomes Rodrigues; Persuhn, Darlene Camati; Gonçalves, Maria Da Conceição Rodrigues

    2016-08-01

    Previous studies have shown that watermelon extract reduces blood pressure through vasodilation. However, those studies have not verified whether sympathetic nervous activity is influenced by watermelon extract. This study aimed to evaluate the effect of supplementation with watermelon extract for 6 weeks on blood pressure and sympathovagal balance of prehypertensive and hypertensive individuals. Forty volunteers participated in a randomized, double-blind, experimental and placebo-controlled study. They consumed 6 g of watermelon extract daily (n = 20; age 48.7 ± 1.9 years, 10 men) or a placebo (n = 20; age 47.4 ± 1.2 years, 11 men) for 6 weeks. Blood pressure and cardiac autonomic modulation were measured. Watermelon extract promoted a significant reduction in systolic (137.8 ± 3.9 to 126.0 ± 4.0 mmHg, p watermelon extract reduces systolic and diastolic blood pressure in prehypertensive and hypertensive individuals, but does not alter the cardiac autonomic modulation of these individuals.

  3. A novel, intelligent, pressure-sensing colostomy plug for reducing fecal leakage.

    Science.gov (United States)

    Chen, Fei; Li, Zhi-Chao; Li, Qiang; Liang, Fei-Xue; Guo, Xiong-Bo; Huang, Zong-Hai

    2015-06-01

    This study aims to describe and report the effectiveness of a novel, pressure-sensing colostomy plug for reducing fecal leakage. Nine miniature Tibetan pigs, aged 6-8 months, were given colostomies and divided into three groups (n = 3 each group). A novel pressure-sensing colostomy plug was placed in each pig and set to indicate when intestinal pressures of either 5, 10, or 15 mm Hg, respectively, were reached. When the pressure thresholds were reached, the animals' bowels were examined for the presence of stool and/or stomal leakage, and the data were recorded at weeks 1, 4, and 8 after surgery. The colostomy plug calibrated to 15 mm Hg pressure demonstrated the greatest accuracy in predicting the presence of stool in the bowels of study animals, averaging >90% sensitivity. In general, the sensitivity for predicting the presence of stool did not vary significantly over time, though there was a slight increase in accuracy in the 5 mm Hg group at later time-points. The sensitivity for predicting stool in the bowel did not change significantly over time in any of the three groups. Stomal leakage was found to be inversely proportional to the pressure-sensor setting, in that the 15 mm Hg group exhibited the greatest amount of leakage. This difference, however, was found to be significant only at week 1 postsurgery. The intelligent, pressure-sensing colostomy plug was able to accurately predict the presence of stool in the bowel and maintain continence, allowing negligible leakage. Copyright © 2015 International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  4. Indigeneous design and development of differential pressure reducing valves for PHWRs (Paper No. 055)

    International Nuclear Information System (INIS)

    Soni, N.L.; Agrawal, R.C.; Chandra, Rajesh

    1987-02-01

    On load fuelling of Pressurised Heavy Water Reactors (PHWRs) is being achieved with the help of Fuelling Machine (F/M). Various actuations are to be carried out inside the F/M magazine pressure housing with the help of high pressure water hydraulic actuators. A constant differential pressure is required to be maintained between pressurized magazine housing and the actuators-supply line for proper operation of the actuators which are to be located inside it. This is achieved with the help of the Differential Pressure Reducing Valve (DPRV). So far these valves have been procured only from a single foreign supplier. In March 1980, the price of each valve was US dollars 3100.00. Dependence on a single foreign supplier may create problems of timely procurement. An effort was made to design and manufacture the DPRV indigensouly meeting the stringent specifications. Theoretical study of single acting DPRV was carried out and design criteria were established. The valve was tested for its performance and was found satisfactory. (author). 8 figs

  5. Abstracts of 2. international conference C-BN and diamond crystallization under reduced pressure

    International Nuclear Information System (INIS)

    1995-01-01

    The important problem and the last advanced one from the view point of electronic materials sciences is the new A III B V compounds creation and investigation of their properties. This domain was the main subject of the 2. International Conference on C-BN and diamond crystallization under reduced pressure. The conference has been divided into 8 sessions. They were: opening address, c-BN, new materials, posters, diamond, applications, posters

  6. Reducing water losses via intelligent pressure management; Reduzierung von Wasserverlusten durch intelligentes Druckmanagement

    Energy Technology Data Exchange (ETDEWEB)

    Oppinger, Peter [VAG-Armaturen GmbH, Mannheim (Germany). Marketing

    2008-03-15

    Leaks in water pipes and leaking municipal water-transmission and piping systems, particularly in developing and threshold countries account for water-losses of up to 50% of the water supplied by the waterworks. This article examines three different solutions for effective pressure management on the basis of an intelligent control system, by means of which water-losses can be reduced to a stable and economically rational level. (orig.)

  7. Encapsulation of azithromycin into polymeric microspheres by reduced pressure-solvent evaporation method

    DEFF Research Database (Denmark)

    Li, Xiujuan; Chang, Si; Du, Guangsheng

    2012-01-01

    Azithromycin loaded microspheres with blends of poly-l-lactide and ploy-D,L-lactide-co-glycolide as matrices were prepared by the atmosphere-solvent evaporation (ASE) and reduced pressure-solvent evaporation (RSE) method. Both the X-ray diffraction spectra and DSC thermographs demonstrated...... characteristics and release profiles of microspheres. In conclusion, the overall improvement of microspheres in appearance, encapsulation efficiency and controlled drug release through the RSE method could be easily fulfilled under optimal preparation conditions....

  8. Blood pressure reducing effects of Phalaris canariensis in normotensive and spontaneously hypertensive rats.

    Science.gov (United States)

    Passos, Clévia Santos; Carvalho, Lucimeire Nova; Pontes, Roberto Braz; Campos, Ruy Ribeiro; Ikuta, Olinda; Boim, Mirian Aparecida

    2012-02-01

    The birdseed Phalaris canariensis (Pc) is popularly used as an antihypertensive agent. The aqueous extract of Pc (AEPc) was administered in adult normotensive Wistar rats and spontaneously hypertensive rats (SHR) and in prehypertensive young SHR (SHR(Y), 3 weeks old). Animals received AEPc (400 mg·kg(-1)·day(-1), by gavage) for 30 days, then groups were divided into 2 subgroups: one was treated for another 30 days and the other received water instead of AEPc for 30 days. AEPc reduced systolic blood pressure (SBP) in both adult groups; however, treatment interruption was followed by a gradual return of the SBP to baseline levels. SHR(Y) became hypertensive 30 days after weaning. AEPc minimized the increase in SBP in SHR(Y), but blood pressure rose to levels similar to those in the untreated group with treatment interruption. There were no changes in renal function, diuresis, or Na(+) excretion. Pc is rich in tryptophan, and the inhibition of the metabolism of tryptophan to kynurenine, a potential vasodilator factor, prevented the blood pressure reducing effect of AEPc. Moreover, AEPc significantly reduced sympathoexcitation. Data indicate that the metabolic derivative of tryptophan, kynurenine, may be a mediator of the volume-independent antihypertensive effect of Pc, which was at least in part mediated by suppression of the sympathetic tonus.

  9. Pressure-reducing interventions among persons with pressure ulcers: results from the first three national pressure ulcer prevalence surveys in Sweden.

    Science.gov (United States)

    Bååth, Carina; Idvall, Ewa; Gunningberg, Lena; Hommel, Ami

    2014-02-01

    The overall aim of this study was to describe preventive interventions among persons with pressure ulcer (PU) in three nationwide PU prevalence surveys in Sweden. A cross-sectional research design was used; more than 70 000 persons from different hospitals and nursing homes participated in the three prevalence surveys conducted in March 2011, October 2011 and March 2012. The methodology used was that recommended by the European Pressure Ulcers Advisory Panel. The overall prevalence of PU categories I-IV in hospitals was 16.6%, 14.4% and 16.1%, respectively. Corresponding figures for nursing homes were 14.5%, 14.2% and 11.8%, respectively. Heel protection/floating heels and sliding sheets were more frequently planned for persons with PU category I. Despite the three prevalence studies that have showed high prevalence of PU the use of preventing interventions is still not on an acceptable level. Heel protection/floating heels and sliding sheets were more frequently planned for persons with PUs, and individual-planned repositioning also increased. However, when persons already have a PU they should all have pressure-reducing preventive interventions to prevent the development of more PUs. Preventing PUs presents a challenge even when facilities have prevention programmes. A PU prevention programme requires an enthusiastic leader who will maintain the team's focus and direction for all staff involved in patient care. © 2013 John Wiley & Sons, Ltd.

  10. Surgical treatment reduces blood pressure in children with unilateral congenital hydronephrosis.

    Science.gov (United States)

    Al-Mashhadi, Ammar; Nevéus, Tryggve; Stenberg, Arne; Karanikas, Birgitta; Persson, A Erik G; Carlström, Mattias; Wåhlin, Nils

    2015-04-01

    Renal disorders can cause hypertension, but less is known about the influence of hydronephrosis on blood pressure. Hydronephrosis due to pelvo-ureteric junction obstruction (PUJO) is a fairly common condition (incidence in newborns of 0.5-1%). Although hypertensive effects of hydronephrosis have been suggested, this has not been substantiated by prospective studies in humans [1-3]. Experimental studies with PUJO have shown that animals with induced hydronephrosis develop salt-sensitive hypertension, which strongly correlate to the degree of obstruction [4-7]. Moreover, relief of the obstruction normalized blood pressure [8]. In this first prospective study our aim was to study the blood pressure pattern in pediatric patients with hydronephrosis before and after surgical correction of the ureteral obstruction. Specifically, we investigated if preoperative blood pressure is reduced after surgery and if split renal function and renographic excretion curves provide any prognostic information. Twelve patients with unilateral congenital hydronephrosis were included in this prospective study. Ambulatory blood pressure (24 h) was measured preoperatively and six months after surgery. Preoperative evaluations of bilateral renal function by Tc99m-MAG3 scintigraphy, and renography curves, classified according to O'Reilly, were also performed. As shown in the summary figure, postoperative systolic (103 ± 2 mmHg) and diastolic (62 ± 2 mmHg) blood pressure were significantly lower than those obtained preoperatively (110 ± 4 and 69 ± 2 mmHg, respectively), whereas no changes in circadian variation or pulse pressure were observed. Renal functional share of the hydronephrotic kidney ranged from 11 to 55%. There was no correlation between the degree of renal function impairment and the preoperative excretory pattern, or between the preoperative excretory pattern and the blood pressure reduction postoperatively. However, preoperative MAG3 function of the affected kidney correlated

  11. [A project to reduce the incidence of facial pressure ulcers caused by prolonged surgery with prone positioning].

    Science.gov (United States)

    Lee, Wen-Yi; Lin, Pao-Chen; Weng, Chia-Hsing; Lin, Yi-Lin; Tsai, Wen-Lin

    2012-06-01

    We observed in our institute a 13.6% incidence of prolonged surgery (>4 hours) induced facial pressure ulcers that required prone positioning. Causes identified included: (1) customized silicon face pillows used were not suited for every patient; (2) our institute lacked a standard operating procedure for prone positioning; (3) our institute lacked a postoperative evaluation and audit procedure for facial pressure ulcers. We designed a strategy to reduce post-prolonged surgery facial pressure ulcer incidence requiring prone positioning by 50% (i.e., from 13.6% to 6.8%). We implemented the following: (1) Created a new water pillow to relieve facial pressure; (2) Implemented continuing education pressure ulcer prevention and evaluation; (3) Established protocols on standard care for prone-position patients and proper facial pressure ulcer identification; (4) Established a face pressure ulcers accident reporting mechanism; and (5) Established an audit mechanism facial pressure ulcer cases. After implementing the resolution measures, 116 patients underwent prolonged surgery in a prone position (mean operating time: 298 mins). None suffered from facial pressure ulcers. The measures effectively reduced the incidence of facial pressure ulcers from 13.6% to 0.0%. The project used a water pillow to relieve facial pressure and educated staff to recognize and evaluate pressure ulcers. These measures were demonstrated effective in reducing the incidence of facial pressure ulcers caused by prolonged prone positioning.

  12. Perfusion dyssynchrony analysis

    NARCIS (Netherlands)

    Chiribiri, A.; Villa, A.D.M.; Sammut, E.; Breeuwer, M.; Nagel, E.

    2015-01-01

    AIMS: We sought to describe perfusion dyssynchrony analysis specifically to exploit the high temporal resolution of stress perfusion CMR. This novel approach detects differences in the temporal distribution of the wash-in of contrast agent across the left ventricular wall. METHODS AND RESULTS:

  13. Evidence-based blood pressure reducing actions of electroacupuncture: mechanisms and clinical application.

    Science.gov (United States)

    Longhurst, John C; Tjen-A-Looi, Stephanie C

    2017-10-25

    Hypertension is a serious world-wide health problem as it increases cardiovascular atherosclerotic risk, stroke and attending morbidity and mortality. Both systolic and diastolic blood pressures and particularly systolic pressure increase with aging. The downsides from pharmacological therapy have led to consideration of additional treatments, including acupuncture, which evokes endogenous neural-hormonal systems to lower blood pressure. Using basic science studies to guide clinical approaches to research, it is apparent that low frequency, low intensity electroacupuncture reduces sympathetic outflow in approximately 70% of patients with mild to moderate hypertension who are off antihypertensive drugs. Systolic and, to a lesser extent, diastolic arterial blood pressures can be lowered over two to four weeks for prolonged periods, lasting as long as one month, after cessation of an eight weeks of once weekly stimulation. Many questions about long-term therapy, treatment of resistant patients and efficacy in patients on medication remain to be studied. Current data, however, suggest that there may be a role of acupuncture in treatment of hypertension.

  14. Are Pressure Vests Beneficial at Reducing Stress in Anxious and Fearful Dogs?

    Directory of Open Access Journals (Sweden)

    Louise Anne Buckley

    2018-03-01

    Full Text Available PICO questionIn fearful or anxious dogs does wearing a pressure vest, compared to not wearing one, result in reduced behavioural and physiological signs of stress? Clinical bottom lineFour studies of variable quality and limitations were identified that investigated the use of pressure vests, using various physiological and behavioural proxy measures of anxiety. Most behavioural outcome measures associated with a positive effect were subjective assessments, with unblinded assessors. Subjectively, many of the owners believed that pressure vests had a positive effect on their dogs’ anxiety levels.The take home message for the veterinary professional is that pressure vests may have small but beneficial effects on canine anxiety click to tweet and that habituating the dog to the vest, assessing for comfort and using repeatedly may improve the likelihood of any benefit. However, the owner should be cautioned that they should not expect their dog’s anxiety to be fully alleviated or prevented, and it may have no beneficial effect at all. 

  15. Intelligent Pressure Management to Reduce Leakage in Urban Water Supply Networks, A Case Study of Sarafrazan District, Mashhad

    OpenAIRE

    Mohammad Soltani Asl; Mahmoud Faghfour Maghrebi

    2009-01-01

    Water losses are inevitable in urban water distribution systems. The two approaches adopted nowadays to combat this problem include management of hydraulic parameters such as pressure and leakage detection in the network. Intellitgent pressure management is a suitable technique for controlling leakage and reducing damages due to high operating pressures in a network. This paper aims to investigate the effects of pressure reduction on leakage. The EPANET 2.10 software is used to simulate the w...

  16. Laser doppler perfusion imaging

    International Nuclear Information System (INIS)

    Waardell, K.

    1992-01-01

    Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light. A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software. A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.2%. The median sampling depth of the laser beam was simulated by a Monte Carlo technique and estimated to 235 μm. The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation. The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. 22 refs

  17. Intelligent Pressure Management to Reduce Leakage in Urban Water Supply Networks, A Case Study of Sarafrazan District, Mashhad

    Directory of Open Access Journals (Sweden)

    Mohammad Soltani Asl

    2009-09-01

    Full Text Available Water losses are inevitable in urban water distribution systems. The two approaches adopted nowadays to combat this problem include management of hydraulic parameters such as pressure and leakage detection in the network. Intellitgent pressure management is a suitable technique for controlling leakage and reducing damages due to high operating pressures in a network. This paper aims to investigate the effects of pressure reduction on leakage. The EPANET 2.10 software is used to simulate the water distribution network in the Sarafrazan District,Mashhad, assuming leakage from network nodes. The results are then used to develop a pressure variation program based on the patterns obtained from the simulation, which is applied to the pressure reducing valve. The results show that pressure management can reduce nightly leakage by up to 35% while maintaining a more uniform pressure distribution. Implementation of the time-dependent pressure pattern by applying programmable pressure reducing valves in a real urban water distribution network is feasible and plays a key role in reducing water losses to leakage.

  18. Highly sensitive micromachined capacitive pressure sensor with reduced hysteresis and low parasitic capacitance

    DEFF Research Database (Denmark)

    Pedersen, Thomas; Fragiacomo, Giulio; Hansen, Ole

    2009-01-01

    This paper describes the design and fabrication of a capacitive pressure sensor that has a large capacitance signal and a high sensitivity of 76 pF/bar in touch mode operation. Due to the large signal, problems with parasitic capacitances are avoided and hence it is possible to integrate the sensor...... bonding to create vacuum cavities. The exposed part of the sensor is perfectly flat such that it can be coated with corrosion resistant thin films. Hysteresis is an inherent problem in touch mode capacitive pressure sensors and a technique to significantly reduce it is presented....... with a discrete components electronics circuit for signal conditioning. Using an AC bridge electronics circuit a resolution of 8 mV/mbar is achieved. The large signal is obtained due to a novel membrane structure utilizing closely packed hexagonal elements. The sensor is fabricated in a process based on fusion...

  19. Oxidation of C/SiC Composites at Reduced Oxygen Partial Pressures

    Science.gov (United States)

    Opila, Elizabeth J.; Serra, Jessica

    2009-01-01

    Carbon-fiber reinforced SiC (C/SiC) composites are proposed for leading edge applications of hypersonic vehicles due to the superior strength of carbon fibers at high temperatures (greater than 1500 C). However, the vulnerability of the carbon fibers in C/SiC to oxidation over a wide range of temperatures remains a problem. Previous oxidation studies of C/SiC have mainly been conducted in air or oxygen, so that the oxidation behavior of C/SiC at reduced oxygen partial pressures of the hypersonic flight regime are less well understood. In this study, both carbon fibers and C/SiC composites were oxidized over a wide range of temperatures and oxygen partial pressures to facilitate the understanding and modeling of C/SiC oxidation kinetics for hypersonic flight conditions.

  20. Placental Growth Factor Reduces Blood Pressure in a Uteroplacental Ischemia Model of Preeclampsia in Nonhuman Primates.

    Science.gov (United States)

    Makris, Angela; Yeung, Kristen R; Lim, Shirlene M; Sunderland, Neroli; Heffernan, Scott; Thompson, John F; Iliopoulos, Jim; Killingsworth, Murray C; Yong, Jim; Xu, Bei; Ogle, Robert F; Thadhani, Ravi; Karumanchi, S Ananth; Hennessy, Annemarie

    2016-06-01

    An imbalance in the angiogenesis axis during pregnancy manifests as clinical preeclampsia because of endothelial dysfunction. Circulating soluble fms-like tyrosine kinase 1 (sFLT-1) increases and placental growth factor (PlGF) reduces before and during disease. We investigated the clinical and biochemical effects of replenishing the reduced circulating PlGF with recombinant human PlGF (rhPlGF) and thus restoring the angiogenic balance. Hypertensive proteinuria was induced in a nonhuman primate (Papio hamadryas) by uterine artery ligation at 136 days gestation (of a 182-day pregnancy). Two weeks after uteroplacental ischemia, rhPlGF (rhPlGF, n=3) or normal saline (control, n=4) was administered by subcutaneous injection (100 μg/kg per day) for 5 days. Blood pressure was monitored by intra-arterial radiotelemetry and sFLT-1 and PlGF by ELISA. Uteroplacental ischemia resulted in experimental preeclampsia evidenced by increased blood pressure, proteinuria, and endotheliosis on renal biopsy and elevated sFLT-1. PlGF significantly reduced after uteroplacental ischemia. rhPlGF reduced systolic blood pressure in the treated group (-5.2±0.8 mm Hg; from 132.6±6.6 mm Hg to 124.1±7.6 mm Hg) compared with an increase in systolic blood pressure in controls (6.5±3 mm Hg; from 131.3±1.5 mm Hg to 138.6±1.5 mm Hg). Proteinuria reduced in the treated group (-72.7±55.7 mg/mmol) but increased in the control group. Circulating levels of total sFLT-1 were not affected by the administration of PlGF; however, a reduction in placental sFLT-1 mRNA expression was demonstrated. There was no significant difference between the weights or lengths of the neonates in the rhPlGF or control group; however, this study was not designed to assess fetal safety or outcomes. Increasing circulating PlGF by the administration of rhPlGF improves clinical parameters in a primate animal model of experimental preeclampsia. © 2016 American Heart Association, Inc.

  1. Mozart, but not the Beatles, reduces systolic blood pressure in patients with myocardial infarction.

    Science.gov (United States)

    Gruhlke, Luiza Carolina; Patrício, Marcelo Coelho; Moreira, Daniel Medeiros

    2015-12-01

    Music reduces systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) in various clinical situations, but it is unclear whether these changes occur in post-infarction patients. The aim is to evaluate the effects of music on patients with acute myocardial infarction (MI). We evaluated patients with MI and we measured SBP, DBP, HR and double product (DP) two times before the intervention and one time every fifteen minutes with an ambulatory blood pressure monitor. We divided the patients into 3 groups: a group listening to music by Mozart; another listening to a Beatles collection and a third one listening to the radio news. Outcomes were the change in mean SBP, DBP, HR and DP with intervention. We enrolled 60 patients (20 in each group). SBP was significantly reduced in the Mozart group (variation of –7.2 ± 8.5 mmHg) compared to the Beatles group (–1.3 ± 6.2 mmHg) (P = 0.021) and the radio news group (0.6 ± 8.7 mmHg) (P = 0.003). DP was significantly reduced in the Mozart group compared with the News group (–668.5 ± 773.2 vs 31.6 ± 722.1 mmHg) (P = 0.006). There were no differences in DBP and HR. Patients with MI who listened Mozart had a reduction in SBP and DP compared to those who listened to the Beatles or the news.

  2. Using the area under the curve to reduce measurement error in predicting young adult blood pressure from childhood measures.

    Science.gov (United States)

    Cook, Nancy R; Rosner, Bernard A; Chen, Wei; Srinivasan, Sathanur R; Berenson, Gerald S

    2004-11-30

    Tracking correlations of blood pressure, particularly childhood measures, may be attenuated by within-person variability. Combining multiple measurements can reduce this error substantially. The area under the curve (AUC) computed from longitudinal growth curve models can be used to improve the prediction of young adult blood pressure from childhood measures. Quadratic random-effects models over unequally spaced repeated measures were used to compute the area under the curve separately within the age periods 5-14 and 20-34 years in the Bogalusa Heart Study. This method adjusts for the uneven age distribution and captures the underlying or average blood pressure, leading to improved estimates of correlation and risk prediction. Tracking correlations were computed by race and gender, and were approximately 0.6 for systolic, 0.5-0.6 for K4 diastolic, and 0.4-0.6 for K5 diastolic blood pressure. The AUC can also be used to regress young adult blood pressure on childhood blood pressure and childhood and young adult body mass index (BMI). In these data, while childhood blood pressure and young adult BMI were generally directly predictive of young adult blood pressure, childhood BMI was negatively correlated with young adult blood pressure when childhood blood pressure was in the model. In addition, racial differences in young adult blood pressure were reduced, but not eliminated, after controlling for childhood blood pressure, childhood BMI, and young adult BMI, suggesting that other genetic or lifestyle factors contribute to this difference. 2004 John Wiley & Sons, Ltd.

  3. Spontaneous condensation of CHF2Cl vapour at high reduced pressures

    International Nuclear Information System (INIS)

    Bier, K.; Ehrler, F.; Kissau, G.; Lippig, V.; Schorsch, R.

    1977-01-01

    Spontaneous condensation at high reduced pressures was investigated in stationary jets of difluoromonochlormethane vapour (refrigerant R 22) expanding within an annular Laval nozzle. The onset of condensation in the so-called Wilson point was determined by measuring the static pressure along the nozzle axis. For 33 expansions carried out with the same nozzle geometry at different stagnation conditions - with dew points ranging from 32 to 64 per cent of the critical pressure - the Wilson points can be represented by a common Wilson line, which can be extended to the critical point. Considering the real gas properties of the supersaturated vapour, one obtains nucleation rates for the states on the measured Wilson line, which are considerably lower than those resulting from the usual ideal-gas calculation, the difference amounting from 4 to 9 orders of magnitude in the investigated region. A comparison with the collision rate of single molecules shows that the nucleation rates calculated for the real gas according to the classical Volmer-Frenkel thoery are plausible. An adequate interpretation of the experimental results on CHF 2 Cl with the Lothe-Pound theory, however, seems not possible, since the nucleation rate due to that theory would nearly attain and - at higher densities - even exceed the molecular collision rate. (orig.) [de

  4. The application of air pressure difference in reducing indoor radon concentration

    International Nuclear Information System (INIS)

    Leung, J.K.C.; Tso, M.Y.W.

    2000-01-01

    In densely populated tropical cities like Hong Kong, people usually live and work inside high-rise buildings. And because of the hot and humid climate, air conditioning systems are used throughout the year, particularly in commercial buildings. Previous territory-wide surveys have shown that over 10% of commercial buildings in Hong Kong have indoor radon concentrations above 200 Bq m -3 . Since the major source of indoor radon in high-rise buildings is the building materials, increasing ventilation and applying radon barriers on wall surfaces seem to be the only ways to reduce the indoor radon concentration. But it was noted that the ventilation rate the many commercial buildings are not efficient enough to remove the radon because of various reasons such as energy saving, lack of maintenance, etc. In this study, radon mitigation was achieved by reducing the rate of radon exhaled from the building materials. A special laboratory, which has the capability of simulating any meteorological conditions that could be faced by high-rise buildings in Hong Kong, was built. The reduction of radon exhalation rate by applying pressure difference and temperature difference across walls was studied in the laboratory. This paper summarizes the results and tactics for applying pressure difference in existing commercial buildings. A new technique of reducing radon exhalation rate in new buildings by depressurizing the interior of walls was also developed. Tunnels can be embedded in the concrete walls of new buildings during construction. By using simple vacuum pumps, radon exhalation rate from the walls can be reduced significantly by depressurizing the tunnels. The feasibility and applicability of the technique is presented in this paper. (author)

  5. Resistance Exercise Restores Endothelial Function and Reduces Blood Pressure in Type 1 Diabetic Rats

    Directory of Open Access Journals (Sweden)

    Marcelo Mendonça Mota

    2014-07-01

    Full Text Available Background: Resistance exercise effects on cardiovascular parameters are not consistent. Objectives: The effects of resistance exercise on changes in blood glucose, blood pressure and vascular reactivity were evaluated in diabetic rats. Methods: Wistar rats were divided into three groups: control group (n = 8; sedentary diabetic (n = 8; and trained diabetic (n = 8. Resistance exercise was carried out in a squat device for rats and consisted of three sets of ten repetitions with an intensity of 50%, three times per week, for eight weeks. Changes in vascular reactivity were evaluated in superior mesenteric artery rings. Results: A significant reduction in the maximum response of acetylcholine-induced relaxation was observed in the sedentary diabetic group (78.1 ± 2% and an increase in the trained diabetic group (95 ± 3% without changing potency. In the presence of NG-nitro-L-arginine methyl ester, the acetylcholine-induced relaxation was significantly reduced in the control and trained diabetic groups, but not in the sedentary diabetic group. Furthermore, a significant increase (p < 0.05 in mean arterial blood pressure was observed in the sedentary diabetic group (104.9 ± 5 to 126.7 ± 5 mmHg as compared to that in the control group. However, the trained diabetic group showed a significant decrease (p < 0.05 in the mean arterial blood pressure levels (126.7 ± 5 to 105.1 ± 4 mmHg as compared to the sedentary diabetic group. Conclusions: Resistance exercise could restore endothelial function and prevent an increase in arterial blood pressure in type 1 diabetic rats.

  6. Resistance Exercise Restores Endothelial Function and Reduces Blood Pressure in Type 1 Diabetic Rats

    Energy Technology Data Exchange (ETDEWEB)

    Mota, Marcelo Mendonça; Silva, Tharciano Luiz Teixeira Braga da; Fontes, Milene Tavares; Barreto, André Sales; Araújo, João Eliakim dos Santos [Departamento de Fisiologia - Universidade Federal de Sergipe (UFS), São Cristóvão, SE (Brazil); Oliveira, Antônio Cesar Cabral de; Wichi, Rogério Brandão [Departamento de Educação Física - UFS, São Cristóvão, SE (Brazil); Santos, Márcio Roberto Viana, E-mail: marciorvsantos@bol.com.br [Departamento de Fisiologia - Universidade Federal de Sergipe (UFS), São Cristóvão, SE (Brazil)

    2014-07-15

    Resistance exercise effects on cardiovascular parameters are not consistent. The effects of resistance exercise on changes in blood glucose, blood pressure and vascular reactivity were evaluated in diabetic rats. Wistar rats were divided into three groups: control group (n = 8); sedentary diabetic (n = 8); and trained diabetic (n = 8). Resistance exercise was carried out in a squat device for rats and consisted of three sets of ten repetitions with an intensity of 50%, three times per week, for eight weeks. Changes in vascular reactivity were evaluated in superior mesenteric artery rings. A significant reduction in the maximum response of acetylcholine-induced relaxation was observed in the sedentary diabetic group (78.1 ± 2%) and an increase in the trained diabetic group (95 ± 3%) without changing potency. In the presence of NG-nitro-L-arginine methyl ester, the acetylcholine-induced relaxation was significantly reduced in the control and trained diabetic groups, but not in the sedentary diabetic group. Furthermore, a significant increase (p < 0.05) in mean arterial blood pressure was observed in the sedentary diabetic group (104.9 ± 5 to 126.7 ± 5 mmHg) as compared to that in the control group. However, the trained diabetic group showed a significant decrease (p < 0.05) in the mean arterial blood pressure levels (126.7 ± 5 to 105.1 ± 4 mmHg) as compared to the sedentary diabetic group. Resistance exercise could restore endothelial function and prevent an increase in arterial blood pressure in type 1 diabetic rats.

  7. Resistance Exercise Restores Endothelial Function and Reduces Blood Pressure in Type 1 Diabetic Rats

    International Nuclear Information System (INIS)

    Mota, Marcelo Mendonça; Silva, Tharciano Luiz Teixeira Braga da; Fontes, Milene Tavares; Barreto, André Sales; Araújo, João Eliakim dos Santos; Oliveira, Antônio Cesar Cabral de; Wichi, Rogério Brandão; Santos, Márcio Roberto Viana

    2014-01-01

    Resistance exercise effects on cardiovascular parameters are not consistent. The effects of resistance exercise on changes in blood glucose, blood pressure and vascular reactivity were evaluated in diabetic rats. Wistar rats were divided into three groups: control group (n = 8); sedentary diabetic (n = 8); and trained diabetic (n = 8). Resistance exercise was carried out in a squat device for rats and consisted of three sets of ten repetitions with an intensity of 50%, three times per week, for eight weeks. Changes in vascular reactivity were evaluated in superior mesenteric artery rings. A significant reduction in the maximum response of acetylcholine-induced relaxation was observed in the sedentary diabetic group (78.1 ± 2%) and an increase in the trained diabetic group (95 ± 3%) without changing potency. In the presence of NG-nitro-L-arginine methyl ester, the acetylcholine-induced relaxation was significantly reduced in the control and trained diabetic groups, but not in the sedentary diabetic group. Furthermore, a significant increase (p < 0.05) in mean arterial blood pressure was observed in the sedentary diabetic group (104.9 ± 5 to 126.7 ± 5 mmHg) as compared to that in the control group. However, the trained diabetic group showed a significant decrease (p < 0.05) in the mean arterial blood pressure levels (126.7 ± 5 to 105.1 ± 4 mmHg) as compared to the sedentary diabetic group. Resistance exercise could restore endothelial function and prevent an increase in arterial blood pressure in type 1 diabetic rats

  8. The role of magnetic energy on plasma localization during the glow discharge under reduced pressure

    Directory of Open Access Journals (Sweden)

    Chodun Rafal

    2016-06-01

    Full Text Available In this work, we present the first results of our research on the synergy of fields, electric and magnetic, in the initiation and development of glow discharge under reduced pressure. In the two-electrode system under reduced pressure, the breakdown voltage characterizes a minimum energy input of the electric field to initiate and sustain the glow discharge. The glow discharge enhanced by the magnetic field applied just above the surface of the cathode influences the breakdown voltage decreasing its value. The idea of the experiment was to verify whether the contribution of potential energy of the magnetic field applied around the cathode is sufficiently effective to locate the plasma of glow discharge to the grounded cathode, which, in fact, is the part of a vacuum chamber wall (the anode is positively biased in this case. In our studies, we used the grounded magnetron unit with positively biased anode in order to achieve favorable conditions for the deposition of thin films on fibrous substrates such as fabrics for metallization, assuming that locally applied magnetic field can effectively locate plasma. The results of our studies (Paschen curve with the participation of the magnetic field seem to confirm the validity of the research assumption. What is the most spectacular - the glow discharge was initiated between introduced into the chamber anode and the grounded cathode of magnetron ‘assisted’ by the magnetic field (discharge did not include the area of the anode, which is a part of the magnetron construction.

  9. Ethylene: Response of Fruit Dehiscence to CO(2) and Reduced Pressure.

    Science.gov (United States)

    Lipe, J A; Morgan, P W

    1972-12-01

    These studies were conducted to determine whether ethylene serves as a natural regulator of fruit wall dehiscence, a major visible feature of ripening in some fruits. We employed treatments to inhibit ethylene action or remove ethylene and observed their effect on fruit dehiscence. CO(2) (13%), a competitive inhibitor of ethylene action in many systems, readily delayed dehiscence of detached fruits of cotton (Gossypium hirsutum L.), pecan (Carya illinoensis [Wang.] K. Koch), and okra (Hibiscus esculentus L.). The CO(2) effect was duplicated by placing fruits under reduced pressure (200 millimeters mercury), to promote the escape of ethylene from the tissue. Dehiscence of detached fruits of these species as well as attached cotton fruits was delayed. The delay of dehiscence of cotton and okra by both treatments was achieved with fruit harvested at intervals from shortly after anthesis until shortly before natural dehiscence. Pecan fruits would not dehisce until approximately 1 month before natural dehiscence, and during that time, CO(2) and reduced pressure delayed dehiscence. CO(2) and ethylene were competitive in their effects on cotton fruit dehiscence. All of the results are compatible with a hypothetical role of ethylene as a natural regulator of dehiscence, a dominant aspect of ripening of cotton, pecan, and some other fruits.

  10. Ethylene: Response of Fruit Dehiscence to CO2 and Reduced Pressure 1

    Science.gov (United States)

    Lipe, John A.; Morgan, Page W.

    1972-01-01

    These studies were conducted to determine whether ethylene serves as a natural regulator of fruit wall dehiscence, a major visible feature of ripening in some fruits. We employed treatments to inhibit ethylene action or remove ethylene and observed their effect on fruit dehiscence. CO2 (13%), a competitive inhibitor of ethylene action in many systems, readily delayed dehiscence of detached fruits of cotton (Gossypium hirsutum L.), pecan (Carya illinoensis [Wang.] K. Koch), and okra (Hibiscus esculentus L.). The CO2 effect was duplicated by placing fruits under reduced pressure (200 millimeters mercury), to promote the escape of ethylene from the tissue. Dehiscence of detached fruits of these species as well as attached cotton fruits was delayed. The delay of dehiscence of cotton and okra by both treatments was achieved with fruit harvested at intervals from shortly after anthesis until shortly before natural dehiscence. Pecan fruits would not dehisce until approximately 1 month before natural dehiscence, and during that time, CO2 and reduced pressure delayed dehiscence. CO2 and ethylene were competitive in their effects on cotton fruit dehiscence. All of the results are compatible with a hypothetical role of ethylene as a natural regulator of dehiscence, a dominant aspect of ripening of cotton, pecan, and some other fruits. PMID:16658260

  11. Environmental response nanosilica for reducing the pressure of water injection in ultra-low permeability reservoirs

    Science.gov (United States)

    Liu, Peisong; Niu, Liyong; Li, Xiaohong; Zhang, Zhijun

    2017-12-01

    The super-hydrophobic silica nanoparticles are applied to alter the wettability of rock surface from water-wet to oil-wet. The aim of this is to reduce injection pressure so as to enhance water injection efficiency in low permeability reservoirs. Therefore, a new type of environmentally responsive nanosilica (denote as ERS) is modified with organic compound containing hydrophobic groups and "pinning" groups by covalent bond and then covered with a layer of hydrophilic organic compound by chemical adsorption to achieve excellent water dispersibility. Resultant ERS is homogeneously dispersed in water with a size of about 4-8 nm like a micro-emulsion system and can be easily injected into the macro or nano channels of ultra-low permeability reservoirs. The hydrophobic nanosilica core can be released from the aqueous delivery system owing to its strong dependence on the environmental variation from normal condition to injection wells (such as pH and salinity). Then the exposed silica nanoparticles form a thin layer on the surface of narrow pore throat, leading to the wettability from water-wet to oil-wet. More importantly, the two rock cores with different permeability were surface treated with ERS dispersion with a concentration of 2 g/L, exhibit great reduce of water injection pressure by 57.4 and 39.6%, respectively, which shows great potential for exploitation of crude oil from ultra-low permeability reservoirs during water flooding. [Figure not available: see fulltext.

  12. Escherichia coli morphological changes and lipid A removal induced by reduced pressure nitrogen afterglow exposure.

    Directory of Open Access Journals (Sweden)

    Hayat Zerrouki

    Full Text Available Lipid A is a major hydrophobic component of lipopolysaccharides (endotoxin present in the membrane of most Gram-negative bacteria, and the major responsible for the bioactivity and toxicity of the endotoxin. Previous studies have demonstrated that the late afterglow region of flowing post-discharges at reduced pressure (1-20 Torr can be used for the sterilization of surfaces and of the reusable medical instrumentation. In the present paper, we show that the antibacterial activity of a pure nitrogen afterglow can essentially be attributed to the large concentrations of nitrogen atoms present in the treatment area and not to the UV radiation of the afterglow. In parallel, the time variation of the inactivation efficiency quantified by the log reduction of the initial Escherichia coli (E. coli population is correlated with morphologic changes observed on the bacteria by scanning electron microscopy (SEM for increasing afterglow exposure times. The effect of the afterglow exposure is also studied on pure lipid A and on lipid A extracted from exposed E. coli bacteria. We report that more than 60% of lipid A (pure or bacteria-extracted are lost with the used operating conditions (nitrogen flow QN2 = 1 standard liter per minute (slpm, pressure p = 5 Torr, microwave injected power PMW = 200 W, exposure time: 40 minutes. The afterglow exposure also results in a reduction of the lipid A proinflammatory activity, assessed by the net decrease of the redox-sensitive NFκB transcription factor nuclear translocation in murine aortic endothelial cells stimulated with control vs afterglow-treated (pure and extracted lipid A. Altogether these results point out the ability of reduced pressure nitrogen afterglows to neutralize the cytotoxic components in Gram-negative bacteria.

  13. Estabilishing requirements for the next generation of pressurized water reactors--reducing the uncertainty

    International Nuclear Information System (INIS)

    Chernock, W.P.; Corcoran, W.R.; Rasin, W.H.; Stahlkopf, K.E.

    1987-01-01

    The Electric Power Research Institute is managing a major effort to establish requirements for the next generation of U.S. light water reactors. This effort is the vital first step in preserving the viability of the nuclear option to contribute to meet U.S. national electric power capacity needs in the next century. Combustion Engineering, Inc. and Duke Power Company formed a team to participate in the EPRI program which is guided by a Utility Steering committee consisting of experienced utility technical executives. A major thrust of the program is to reduce the uncertainties which would be faced by the utility executives in choosing the nuclear option. The uncertainties to be reduced include those related to safety, economic, operational, and regulatory aspects of advanced light water reactors. This paper overviews the Requirements Document program as it relates to the U.S. Advanced Light Water Reactor (ALWR) effort in reducing these uncertainties and reports the status of efforts to establish requirements for the next generation of pressurized water reactors. It concentrates on progress made in reducing the uncertainties which would deter selection of the nuclear option for contributing to U.S. national electric power capacity needs in the next century and updates previous reports in the same area. (author)

  14. Steam Pressure-Reducing Station Safety and Energy Efficiency Improvement Project

    Energy Technology Data Exchange (ETDEWEB)

    Lower, Mark D [ORNL; Christopher, Timothy W [ORNL; Oland, C Barry [ORNL

    2011-06-01

    The Facilities and Operations (F&O) Directorate is sponsoring a continuous process improvement (CPI) program. Its purpose is to stimulate, promote, and sustain a culture of improvement throughout all levels of the organization. The CPI program ensures that a scientific and repeatable process exists for improving the delivery of F&O products and services in support of Oak Ridge National Laboratory (ORNL) Management Systems. Strategic objectives of the CPI program include achieving excellence in laboratory operations in the areas of safety, health, and the environment. Identifying and promoting opportunities for achieving the following critical outcomes are important business goals of the CPI program: improved safety performance; process focused on consumer needs; modern and secure campus; flexibility to respond to changing laboratory needs; bench strength for the future; and elimination of legacy issues. The Steam Pressure-Reducing Station (SPRS) Safety and Energy Efficiency Improvement Project, which is under the CPI program, focuses on maintaining and upgrading SPRSs that are part of the ORNL steam distribution network. This steam pipe network transports steam produced at the ORNL steam plant to many buildings in the main campus site. The SPRS Safety and Energy Efficiency Improvement Project promotes excellence in laboratory operations by (1) improving personnel safety, (2) decreasing fuel consumption through improved steam system energy efficiency, and (3) achieving compliance with applicable worker health and safety requirements. The SPRS Safety and Energy Efficiency Improvement Project being performed by F&O is helping ORNL improve both energy efficiency and worker safety by modifying, maintaining, and repairing SPRSs. Since work began in 2006, numerous energy-wasting steam leaks have been eliminated, heat losses from uninsulated steam pipe surfaces have been reduced, and deficient pressure retaining components have been replaced. These improvements helped ORNL

  15. Pulmonary perfusion ''without ventilation''

    International Nuclear Information System (INIS)

    Chapman, C.N.; Sziklas, J.J.; Spencer, R.P.; Rosenberg, R.J.

    1983-01-01

    An 88-yr-old man, with prior left upper lobectomy and phrenic nerve injury, had a ventilation/perfusion lung image. Both wash-in and equilibrium ventilation images showed no radioactive gas in the left lung. Nevertheless, the left lung was perfused. A similar result was obtained on a repeat study 8 days later. Delayed images, during washout, showed some radioactive gas in the left lung. Nearly absent ventilation (but continued perfusion) of that lung might have been related to altered gas dynamics brought about by the prior lobectomy, a submucosal bronchial lesion, phrenic nerve damage, and limited motion of the left part of the diaphragm. This case raises the issue of the degree of ventilation (and the phase relationship between the lungs) required for the entry of radioactive gas into a diseased lung, and the production of a ''reversed ventilation/perfusion mismatch.''

  16. Myocardial perfusion in type 2 diabetes with left ventricular hypertrophy

    DEFF Research Database (Denmark)

    Hesse, Birger; Meyer, Christian; Nielsen, Flemming S

    2004-01-01

    The purpose of this study was to assess whether acute angiotensin-converting enzyme (ACE) inhibition would improve myocardial perfusion and perfusion reserve in a subpopulation of normotensive patients with diabetes and left ventricular hypertrophy (LVH), both independent risk factors of coronary...... disease. Using positron emission tomography (PET), we investigated the response of regional myocardial perfusion to acute ACE inhibition with i.v. infusion of perindoprilat (vs saline infusion as control, minimum interval 3 days) in 12 diabetic patients with LVH. Myocardial perfusion was quantified...... with controls, maximal perfusion was reduced in patients (1.8+/-0.6 vs 2.5+/-1.0 ml min(-1) g(-1); P2.7+/-1.0 vs 3.6+/-1.3; P=0.059). During perindoprilat infusion, myocardial perfusion reserve in patients increased to 3.9+/-0.9 ( P

  17. Thalidomide ameliorates portal hypertension via nitric oxide synthase independent reduced systolic blood pressure.

    Science.gov (United States)

    Theodorakis, Nicholas G; Wang, Yining N; Korshunov, Vyacheslav A; Maluccio, Mary A; Skill, Nicholas J

    2015-04-14

    NOS(-/-) and iNOS(-/-) PVL mice, after which time levels returned to the respective baseline. Thalidomide does not reduce portal pressure in the murine PVL model by modulation of NO biosynthesis. Rather, thalidomide reduces PHT by decreasing MAP by an undetermined mechanism.

  18. Reduced-pressure chemical vapor deposition of boron-doped Si and Ge layers

    International Nuclear Information System (INIS)

    Bogumilowicz, Y.; Hartmann, J.M.

    2014-01-01

    We have studied the in-situ boron (B) doping of germanium (Ge) and silicon (Si) in Reduced Pressure-Chemical Vapor Deposition. Three growth temperatures have been investigated for the B-doping of Ge: 400, 600 and 750 °C at a constant growth pressure of 13300 Pa (i.e. 100 Torr). The B concentration in the Ge:B epilayer increases linearly with the diborane concentration in the gaseous phase. Single-crystalline Ge:B layers with B concentrations in-between 9 ∙ 10 17 and 1 ∙ 10 20 cm −3 were achieved. For the in-situ B doping of Si at 850 °C, two dichlorosilane mass flow ratios (MFR) have been assessed: F[SiH 2 Cl 2 ]/F[H 2 ] = 0.0025 and F[SiH 2 Cl 2 ]/F[H 2 ] = 0.0113 at a growth pressure of 2660 Pa (i.e. 20 Torr). Linear boron incorporation with the diborane concentration in the gas phase has been observed and doping levels in-between 3.5 ∙ 10 17 and 1 ∙ 10 20 cm −3 were achieved. We almost kept the same ratio of B versus Si atoms in the gas phase and in the Si epilayer. By contrast, roughly half of the B atoms present in the gas phase were incorporated in the Ge:B layers irrespective of the growth temperature. X-Ray Diffraction (XRD) allowed us to extract from the angular position of the Ge:B layer diffraction peak the substitutional B concentration. Values close to the B concentrations obtained by 4-probe resistivity measurements were obtained. Ge:B layers were smooth (< 1 m root mean square roughness associated with 20 × 20 μm 2 Atomic Force Microscopy images). Only for high F[B 2 H 6 ]/F[GeH 4 ] MFR (3.2 10 −3 ) did the Ge:B layers became rough; they were however still mono-crystalline (XRD). Above this MFR value, Ge:B layers became polycrystalline. - Highlights: • Boron doping of germanium and silicon in Reduced Pressure-Chemical Vapor Deposition • Linear boron incorporation in Ge:B and Si:B with the diborane flow • Single-crystal Ge:B layers with B concentrations in-between 9 ∙ 10 17 and 1 ∙ 10 20 cm −3 • Single-crystal Si

  19. Regional cerebral perfusion in cardiovascular reflex syncope

    International Nuclear Information System (INIS)

    Toeyry, J.P.; Kuikka, J.T.; Laensimies, E.A.

    1997-01-01

    Little is known about the regional cerebral perfusion in subjects with presyncope or syncope, and the impact that autonomic nervous dysfunction has on it. Seven subjects with cardiovascular vasodepressor reflex syncope were studied. A baseline test was performed with the patients standing in the 70 upright position, while the passive head-up tilt table test with and without isoprenaline infusion was employed for provocation. Regional cerebral perfusion was assessed by means of single-photon emission tomography with technetium-99m labelled V-oxo-1,2-N,N 1 -ethylenedylbis-l-cysteine diethylester (baseline, and during blood pressure decline in the provocation test) and the autonomic nervous function by means of spectral analysis of heart rate variability (baseline, and before blood pressure decline in the provocation test). Every subject showed an abrupt decline in blood pressure in the provocation test (five with presyncope and two with syncope). The systolic and diastolic blood pressures decreased significantly (P<0.001) between the baseline and the provocation study time points (radiopharmaceutical injection and lowest systolic blood pressure). Mean cerebral perfusion as average count densities decreased upon provocation as compared with baseline (190±63 vs 307±90 counts/voxel, respectively, P=0.013). Hypoperfusion was most pronounced in the frontal lobe. These results suggest that cerebral perfusion decreases markedly during presyncope or syncope with systemic blood pressure decline in subjects with cardiovascular vasodepressor syncope. Furthermore, the autonomic nervous function remains unchanged before the systemic blood pressure decline. (orig.). With 3 figs., 2 tabs

  20. Maca reduces blood pressure and depression, in a pilot study in postmenopausal women.

    Science.gov (United States)

    Stojanovska, L; Law, C; Lai, B; Chung, T; Nelson, K; Day, S; Apostolopoulos, V; Haines, C

    2015-02-01

    Lepidium meyenii (Maca) has been used for centuries for its fertility-enhancing and aphrodisiac properties. In an Australian study, Maca improved anxiety and depressive scores. The effects of Maca on hormones, lipids, glucose, serum cytokines, blood pressure, menopausal symptoms and general well-being in Chinese postmenopausal women were evaluated. A randomized, double-blind, placebo-controlled, cross-over study was conducted in 29 postmenopausal Hong Kong Chinese women. They received 3.3 g/day of Maca or placebo for 6 weeks each, in either order, over 12 weeks. At baseline, week 6 and week 12, estradiol, follicle stimulating hormone (FSH), sex hormone binding globulin (SHBG), thyroid stimulating hormone (TSH), full lipid profiles, glucose and serum cytokines were measured. The Greene Climacteric, SF-36 Version 2, Women's Health Questionnaire and Utian Quality of Life Scales were used to assess the severity of menopausal symptoms and health-related quality of life. There were no differences in estradiol, FSH, TSH, SHBG, glucose, lipid profiles and serum cytokines amongst those who received Maca as compared to the placebo group; however, significant decreases in diastolic blood pressure and depression were apparent after Maca treatment. Maca did not exert hormonal or immune biological action in the small cohort of patients studied; however, it appeared to reduce symptoms of depression and improve diastolic blood pressure in Chinese postmenopausal women. Although results are comparable to previous similar published studies in postmenopausal women, there might be a cultural difference among the Chinese postmenopausal women in terms of symptom reporting.

  1. Focusing polycapillary to reduce parasitic scattering for inelastic x-ray measurements at high pressure

    International Nuclear Information System (INIS)

    Chow, P.; Xiao, Y. M.; Rod, E.; Bai, L. G.; Shen, G. Y.; Sinogeikin, S.; Gao, N.; Ding, Y.; Mao, H.-K.

    2015-01-01

    The double-differential scattering cross-section for the inelastic scattering of x-ray photons from electrons is typically orders of magnitude smaller than that of elastic scattering. With samples 10-100 μm size in a diamond anvil cell at high pressure, the inelastic x-ray scattering signals from samples are obscured by scattering from the cell gasket and diamonds. One major experimental challenge is to measure a clean inelastic signal from the sample in a diamond anvil cell. Among the many strategies for doing this, we have used a focusing polycapillary as a post-sample optic, which allows essentially only scattered photons within its input field of view to be refocused and transmitted to the backscattering energy analyzer of the spectrometer. We describe the modified inelastic x-ray spectrometer and its alignment. With a focused incident beam which matches the sample size and the field of view of polycapillary, at relatively large scattering angles, the polycapillary effectively reduces parasitic scattering from the diamond anvil cell gasket and diamonds. Raw data collected from the helium exciton measured by x-ray inelastic scattering at high pressure using the polycapillary method are compared with those using conventional post-sample slit collimation

  2. Knee arthritis pain is reduced and range of motion is increased following moderate pressure massage therapy.

    Science.gov (United States)

    Field, Tiffany; Diego, Miguel; Gonzalez, Gladys; Funk, C G

    2015-11-01

    The literature on massage therapy effects on knee pain suggests that pain was reduced based on self-report, but little is known about range of motion (ROM) effects. Medical School staff and faculty who had knee arthritis pain were randomly assigned to a moderate pressure massage therapy or a waitlist control group (24 per group). Self-reports included the WOMAC (pain, stiffness and function) and the Pittsburgh Sleep Quality Index. ROM and ROM-related pain were assessed before and after the last sessions. The massage group showed an immediate post-massage increase in ROM and a decrease in ROM-associated pain. On the last versus the first day of the study, the massage group showed greater increases in ROM and decreases in ROM-related pain as well as less self-reported pain and sleep disturbances than the waitlist control group. These data highlight the effectiveness of moderate pressure massage therapy for increasing ROM and lessening ROM-related pain and long-term pain and sleep disturbances. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Pressure drop characteristics in tight-lattice bundles for reduced-moderation water reactors

    International Nuclear Information System (INIS)

    Tamai, Hidesada; Kureta, Masatoshi; Yoshida, Hiroyuki; Akimoto, Hajime

    2004-01-01

    The reduced-moderation water reactor (RMWR) consists of several distinctive structures; a triangular tight-lattice configuration and a double-flat core. In order to design the RMWR core from the point of view of thermal-hydraulics, an evaluation method on pressure drop characteristics in the rod bundles at the tight-lattice configuration is required. In this study, calculated results by the Martinelli-Nelson's and Hancox's correlations were compared with experimental results in 4 x 5 rod bundles and seven-rod bundles. Consequently, the friction loss in two-phase flows becomes smaller at the tight-lattice configuration with the hydraulic diameter less than about 3 mm. This reason is due to the difference of the configuration between the multi-rod bundle and the circular tube and due to the effect of the small hydraulic diameter on the two-phase multiplier. (author)

  4. A jazz-based approach for optimal setting of pressure reducing valves in water distribution networks

    Science.gov (United States)

    De Paola, Francesco; Galdiero, Enzo; Giugni, Maurizio

    2016-05-01

    This study presents a model for valve setting in water distribution networks (WDNs), with the aim of reducing the level of leakage. The approach is based on the harmony search (HS) optimization algorithm. The HS mimics a jazz improvisation process able to find the best solutions, in this case corresponding to valve settings in a WDN. The model also interfaces with the improved version of a popular hydraulic simulator, EPANET 2.0, to check the hydraulic constraints and to evaluate the performances of the solutions. Penalties are introduced in the objective function in case of violation of the hydraulic constraints. The model is applied to two case studies, and the obtained results in terms of pressure reductions are comparable with those of competitive metaheuristic algorithms (e.g. genetic algorithms). The results demonstrate the suitability of the HS algorithm for water network management and optimization.

  5. Preparation of carbon nanotubes by DC arc discharge process under reduced pressure in an air atmosphere

    International Nuclear Information System (INIS)

    Kim, Hyeon Hwan; Kim, Hyeong Joon

    2006-01-01

    Carbon nanotubes (CNTs) were grown using a DC arc discharge process in an air atmosphere and relevant process parameters were investigated. Without using an inert gas, multi walled carbon nanotubes could be synthesized in the deposit area of the cathode even in an air atmosphere, but single walled carbon nanotubes were not detected in the soot area despite using the same process conditions as in the inert gas. The air pressure for the highest yield of multi walled CNTs was 300 Torr. In addition, the quantity of amorphous carbon and other nanoparticles in the process chamber was remarkably reduced by this technique, showing that an efficient, feasible method of large scale CNT fabrication could be achieved by the arc discharge process

  6. Flexible Pressure Sensor Based on PVDF Nanocomposites Containing Reduced Graphene Oxide-Titania Hybrid Nanolayers

    Directory of Open Access Journals (Sweden)

    Aisha Al-Saygh

    2017-01-01

    Full Text Available A novel flexible nanocomposite pressure sensor with a tensile strength of about 47 MPa is fabricated in this work. Nanolayers of titanium dioxide (titania nanolayers, TNL synthesized by hydrothermal method are used to reinforce the polyvinylidene fluoride (PVDF by simple solution mixing. A hybrid composite is prepared by incorporating the TNL (2.5 wt % with reduced graphene oxide (rGO (2.5 wt % synthesized by improved graphene oxide synthesis to form a PVDF/rGO-TNL composite. A comparison between PVDF, PVDF/rGO (5 wt %, PVDF/TNL (5 wt % and PVDF/rGO-TNL (total additives 5 wt % samples are analyzed for their sensing, thermal and dielectric characteristics. The new shape of additives (with sharp morphology, good interaction and well distributed hybrid additives in the matrix increased the sensitivity by 333.46% at 5 kPa, 200.7% at 10.7 kPa and 246.7% at 17.6 kPa compared to the individual PVDF composite of TNL, confirming its possible application in fabricating low cost and light weight pressure sensing devices and electronic devices with reduced quantity of metal oxides. Increase in the β crystallinity percentage and removal of α phase for PVDF was detected for the hybrid composite and linked to the improvement in the mechanical properties. Tensile strength for the hybrid composite (46.91 MPa was 115% higher than that of the neat polymer matrix. Improvement in the wettability and less roughness in the hybrid composites were observed, which can prevent fouling, a major disadvantage in many sensor applications.

  7. Sodium-glucose co-transporter type 2 inhibitors reduce evening home blood pressure in type 2 diabetes with nephropathy.

    Science.gov (United States)

    Takenaka, Tsuneo; Kishimoto, Miyako; Ohta, Mari; Tomonaga, Osamu; Suzuki, Hiromichi

    2017-05-01

    The effects of sodium-glucose co-transporter type 2 inhibitors on home blood pressure were examined in type 2 diabetes with nephropathy. The patients with diabetic nephropathy were screened from medical records in our hospitals. Among them, 52 patients who measured home blood pressure and started to take sodium-glucose co-transporter type 2 inhibitors were selected. Clinical parameters including estimated glomerular filtration rate, albuminuria and home blood pressure for 6 months were analysed. Sodium-glucose co-transporter type 2 inhibitors (luseogliflozin 5 mg/day or canagliflozin 100 mg/day) reduced body weight, HbA1c, albuminuria, estimated glomerular filtration rate and office blood pressure. Although sodium-glucose co-transporter type 2 inhibitors did not alter morning blood pressure, it reduced evening systolic blood pressure. Regression analyses revealed that decreases in evening blood pressure predicted decrements in albuminuria. The present data suggest that sodium-glucose co-transporter type 2 inhibitors suppress sodium overload during daytime to reduce evening blood pressure and albuminuria.

  8. Differing prognostic value of pulse pressure in patients with heart failure with reduced or preserved ejection fraction

    DEFF Research Database (Denmark)

    Jackson, Colette E; Castagno, Davide; Maggioni, Aldo P

    2015-01-01

    ) and 5008 with HF-PEF (828 deaths). Pulse pressure was analysed in quintiles in a multivariable model adjusted for the previously reported Meta-Analysis Global Group in Chronic Heart Failure prognostic variables. Heart failure and reduced ejection fraction patients in the lowest pulse pressure quintile had...... in patients with HF-PEF [ejection fraction (EF) ≥ 50%] and HF-REF. METHODS AND RESULTS: Data from 22 HF studies were examined. Preserved left ventricular ejection fraction (LVEF) was defined as LVEF ≥ 50%. All-cause mortality at 3 years was evaluated in 27 046 patients: 22 038 with HF-REF (4980 deaths......AIMS: Low pulse pressure is a marker of adverse outcome in patients with heart failure (HF) and reduced ejection fraction (HF-REF) but the prognostic value of pulse pressure in patients with HF and preserved ejection fraction (HF-PEF) is unknown. We examined the prognostic value of pulse pressure...

  9. Creatine supplementation reduces sleep need and homeostatic sleep pressure in rats.

    Science.gov (United States)

    Dworak, Markus; Kim, Tae; Mccarley, Robert W; Basheer, Radhika

    2017-06-01

    Sleep has been postulated to promote brain energy restoration. It is as yet unknown if increasing the energy availability within the brain reduces sleep need. The guanidine amino acid creatine (Cr) is a well-known energy booster in cellular energy homeostasis. Oral Cr-monohydrate supplementation (CS) increases exercise performance and has been shown to have substantial effects on cognitive performance, neuroprotection and circadian rhythms. The effect of CS on cellular high-energy molecules and sleep-wake behaviour is unclear. Here, we examined the sleep-wake behaviour and brain energy metabolism before and after 4-week-long oral administration of CS in the rat. CS decreased total sleep time and non-rapid eye movement (NREM) sleep significantly during the light (inactive) but not during the dark (active) period. NREM sleep and NREM delta activity were decreased significantly in CS rats after 6 h of sleep deprivation. Biochemical analysis of brain energy metabolites showed a tendency to increase in phosphocreatine after CS, while cellular adenosine triphosphate (ATP) level decreased. Microdialysis analysis showed that the sleep deprivation-induced increase in extracellular adenosine was attenuated after CS. These results suggest that CS reduces sleep need and homeostatic sleep pressure in rats, thereby indicating its potential in the treatment of sleep-related disorders. © 2017 European Sleep Research Society.

  10. Reduced-order modellin for high-pressure transient flow of hydrogen-natural gas mixture

    Science.gov (United States)

    Agaie, Baba G.; Khan, Ilyas; Alshomrani, Ali Saleh; Alqahtani, Aisha M.

    2017-05-01

    In this paper the transient flow of hydrogen compressed-natural gas (HCNG) mixture which is also referred to as hydrogen-natural gas mixture in a pipeline is numerically computed using the reduced-order modelling technique. The study on transient conditions is important because the pipeline flows are normally in the unsteady state due to the sudden opening and closure of control valves, but most of the existing studies only analyse the flow in the steady-state conditions. The mathematical model consists in a set of non-linear conservation forms of partial differential equations. The objective of this paper is to improve the accuracy in the prediction of the HCNG transient flow parameters using the Reduced-Order Modelling (ROM). The ROM technique has been successfully used in single-gas and aerodynamic flow problems, the gas mixture has not been done using the ROM. The study is based on the velocity change created by the operation of the valves upstream and downstream the pipeline. Results on the flow characteristics, namely the pressure, density, celerity and mass flux are based on variations of the mixing ratio and valve reaction and actuation time; the ROM computational time cost advantage are also presented.

  11. Clinical indicators to monitor patients with risk for ineffective cerebral tissue perfusion

    Directory of Open Access Journals (Sweden)

    Miriam de Abreu Almeida

    2015-04-01

    Full Text Available Objective. Select and validate the clinical indicators to monitor patients on risk for ineffective cerebral tissue perfusion, according to the Nursing Outcomes Classification (NOC. Methodology. Validation study carried out between November 2012 and August 2013, in a Brazilian hospital. Seventeen judges nurses evaluated the clinical indicators of Nursing Outcomes, according to NOC for patients on risk for ineffective cerebral tissue perfusion. In the first stage, were selected the nursing results for the assessment of the studied diagnosis and, in the second nurses assessment the importance of the indicators of the validated results in the previous step through a five points Likert scale (1 = not important to 5 = extremely important. Were used the content validity index (CVI that corresponds to the calculation of weighted averages of them marks awarded for each indicator, as it considered the following weights: 1=0.00, 2=0.25, 3=0.50; 4=0.75; 5=1.00. For categorization, the CVI considered as critical = ≥0.80; supplementary =≥0.50 to 0.79 and were disposed results <0.50. Results. Of the 9 nursing results, only the cerebral tissue perfusion obtained a 100% consensus. The CVI of the 18 indicators of this result showed that five were validated as critical (impaired neurological reflexes, systolic blood pressure, diastolic blood pressure, reduced level of consciousness and mean arterial pressure, 12 were validated as supplementary (Agitation, Impaired cognition, Intracranial pressure, Syncope, Vomiting, Findings of cerebral angiography, Headache, Restlessness, Fever, Unexplained anxiety, listlessness and Hiccughs and one was disposed (carotid bruit. Conclusions. The validation of information about the conditions of risk may allow early intervention to minimize the consequences of ineffective cerebral tissue perfusion.

  12. Correlation between thallium-201 myocardial perfusion defects and the functional severity of coronary artery stenosis as assessed by pressure-derived myocardial fractional flow reserve

    International Nuclear Information System (INIS)

    Yanagisawa, Hidefumi; Chikamori, Taishiro; Tanaka, Nobuhiro

    2002-01-01

    Although a relationship between the coronary pressure-derived fractional flow reserve (FFR) and the presence of myocardial ischemia as demonstrated by radionuclide imaging has been reported in a select group of patients, it remains to be established whether this relation also holds true in actual clinical settings with a heterogeneous group of patients. Accordingly, 194 coronary vessels and their supply territories were evaluated in 165 consecutive patients with suspected or known coronary artery disease. An FFR 201 Tl (p 201 Tl reversibility score (r=-0.62; p<0.0001). These results suggest that the FFR has a significant relationship with scintigraphic evidence of myocardial ischemia and can be regarded as a marker of its presence or absence in patients in actual clinical settings. (author)

  13. Proposal and design of a natural gas liquefaction process recovering the energy obtained from the pressure reducing stations of high-pressure pipelines

    Science.gov (United States)

    Tan, Hongbo; Zhao, Qingxuan; Sun, Nannan; Li, Yanzhong

    2016-12-01

    Taking advantage of the refrigerating effect in the expansion at an appropriate temperature, a fraction of high-pressure natural gas transported by pipelines could be liquefied in a city gate station through a well-organized pressure reducing process without consuming any extra energy. The authors proposed such a new process, which mainly consists of a turbo-expander driven booster, throttle valves, multi-stream heat exchangers and separators, to yield liquefied natural gas (LNG) and liquid light hydrocarbons (LLHs) utilizing the high-pressure of the pipelines. Based on the assessment of the effects of several key parameters on the system performance by a steady-state simulation in Aspen HYSYS, an optimal design condition of the proposed process was determined. The results showed that the new process is more appropriate to be applied in a pressure reducing station (PRS) for the pipelines with higher pressure. For the feed gas at the pressure of 10 MPa, the maximum total liquefaction rate (ytot) of 15.4% and the maximum exergy utilizing rate (EUR) of 21.7% could be reached at the optimal condition. The present process could be used as a small-scale natural gas liquefying and peak-shaving plant at a city gate station.

  14. Laws of physics help explain capillary non-perfusion in diabetic retinopathy.

    Science.gov (United States)

    Stefánsson, E; Chan, Y K; Bek, T; Hardarson, S H; Wong, D; Wilson, D I

    2018-02-01

    The purpose is to use laws of physics to elucidate the mechanisms behind capillary non-perfusion in diabetic retinopathy. In diabetic retinopathy, loss of pericytes weakens capillary walls and the vessel dilates. A dilated capillary has reduced resistance to flow, therefore increased flow in that vessel and decreased in adjoining capillaries. A preferential shunt vessel is thus formed from the dilated capillary and the adjacent capillaries become non-perfused. We apply the laws of Laplace and Hagen-Poiseuille to better understand the phenomena that lead to capillary non-perfusion. These laws of physics can give a foundation for physical or mathematical models to further elucidate this field of study. The law of Laplace predicts that a weaker vessel wall will dilate, assuming constant transmural pressure. The Hagen-Poiseuille equation for flow and the Ostwald-de Waele relationship for viscosity predict that a dilated vessel will receive a higher portion of the fluid flow than the adjoining capillaries. Viscosity will decrease in the dilated vessel, furthering the imbalance and resulting in a patch of non-perfused capillaries next to the dilated 'preferential' shunt vessel. Physical principles support or inspire novel hypotheses to explain poorly understood phenomena in ophthalmology. This thesis of pericyte death and capillary remodelling, which was first proposed by Cogan and Kuwabara, already agrees with histological and angiographical observations in diabetic retinopathy. We have shown that it is also supported by classical laws of physics.

  15. Recent developments in gamma camera technology for myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Bengel, Frank M.

    2010-01-01

    Economic pressure, competition from alternative modalities and an increasing awareness of patient radiation exposure have triggered a rapid development of novel technology for cardiac single-photon emission computed tomography (SPECT) in recent years. The trend clearly goes towards systems with higher sensitivity and resolution, and towards faster acquisition protocols. Those goals are achieved by various measures: On the one hand, several manufacturers have integrated novel semiconductor detector materials together with innovative collimators into dedicated cardiac scanners. On the other hand, new collimators and reconstruction algorithms have lead to increased speed and accuracy of conventional gamma cameras. Imaging times now can be reduced to as much as 10% of that of previous standard protocols, and/or injected activity can be reduced. This is achieved without loss of diagnostic accuracy. These novel developments are still in early phases of clinical implementation. Their potential for a profound change of the clinical practice of myocardial perfusion scintigraphy, however, becomes increasingly obvious. (orig.)

  16. The effect of perfusion and irrigation flow rate variations on NaCl efflux from the isolated, perfused head of the marine teleost, Myoxocephalus octodecimspinosus

    International Nuclear Information System (INIS)

    Claiborne, J.B.; Evans, D.H.

    1981-01-01

    In vivo branchial blood pressure and unidirectional efflux values for NaCl were determined in the marine teleost, Myoxocephalus octodecimspinosus. Utilizing an isolated, perfused head preparation, perfused at in vivo pressure levels, NaCl efflux was measured and compared to in vivo values. The effect of variations in perfusion or irrigation rates on the ion efflux across the gills of the isolated head was also studied. The efflux of 22 Na from the isolated, perfused head was found to be similar to in vivo values and dependent on perfusion flow and pressure. In vitro 36 Cl efflux was lower than the efflux from intact animals and was determined to be flow/pressure independent. Irrigation rate changes at all rates tested did not affect the unidirectional efflux of either ion. (Auth.)

  17. Effect of perfusion and irrigation flow rate variations on NaCl efflux from the isolated, perfused head of the marine teleost, Myoxocephalus octodecimspinosus

    Energy Technology Data Exchange (ETDEWEB)

    Claiborne, J.B. (Miami Univ., Coral Gables, FL (USA)); Evans, D.H. (Mt. Desert Island Biological Laboratory, Salsbury Cove, ME, USA)

    1981-06-01

    In vivo branchial blood pressure and unidirectional efflux values for NaCl were determined in the marine teleost, Myoxocephalus octodecimspinosus. Utilizing an isolated, perfused head preparation, perfused at in vivo pressure levels, NaCl efflux was measured and compared to in vivo values. The effect of variations in perfusion or irrigation rates on the ion efflux across the gills of the isolated head was also studied. The efflux of /sup 22/Na from the isolated, perfused head was found to be similar to in vivo values and dependent on perfusion flow and pressure. In vitro /sup 36/Cl efflux was lower than the efflux from intact animals and was determined to be flow/pressure independent. Irrigation rate changes at all rates tested did not affect the unidirectional efflux of either ion.

  18. Spatio-temporal analysis of blood perfusion by imaging photoplethysmography

    Science.gov (United States)

    Zaunseder, Sebastian; Trumpp, Alexander; Ernst, Hannes; Förster, Michael; Malberg, Hagen

    2018-02-01

    Imaging photoplethysmography (iPPG) has attracted much attention over the last years. The vast majority of works focuses on methods to reliably extract the heart rate from videos. Only a few works addressed iPPGs ability to exploit spatio-temporal perfusion pattern to derive further diagnostic statements. This work directs at the spatio-temporal analysis of blood perfusion from videos. We present a novel algorithm that bases on the two-dimensional representation of the blood pulsation (perfusion map). The basic idea behind the proposed algorithm consists of a pairwise estimation of time delays between photoplethysmographic signals of spatially separated regions. The probabilistic approach yields a parameter denoted as perfusion speed. We compare the perfusion speed versus two parameters, which assess the strength of blood pulsation (perfusion strength and signal to noise ratio). Preliminary results using video data with different physiological stimuli (cold pressure test, cold face test) show that all measures are influenced by those stimuli (some of them with statistical certainty). The perfusion speed turned out to be more sensitive than the other measures in some cases. However, our results also show that the intraindividual stability and interindividual comparability of all used measures remain critical points. This work proves the general feasibility of employing the perfusion speed as novel iPPG quantity. Future studies will address open points like the handling of ballistocardiographic effects and will try to deepen the understanding of the predominant physiological mechanisms and their relation to the algorithmic performance.

  19. Measurement of Outflow Facility Using iPerfusion.

    Directory of Open Access Journals (Sweden)

    Joseph M Sherwood

    Full Text Available Elevated intraocular pressure (IOP is the predominant risk factor for glaucoma, and reducing IOP is the only successful strategy to prevent further glaucomatous vision loss. IOP is determined by the balance between the rates of aqueous humour secretion and outflow, and a pathological reduction in the hydraulic conductance of outflow, known as outflow facility, is responsible for IOP elevation in glaucoma. Mouse models are often used to investigate the mechanisms controlling outflow facility, but the diminutive size of the mouse eye makes measurement of outflow technically challenging. In this study, we present a new approach to measure and analyse outflow facility using iPerfusion™, which incorporates an actuated pressure reservoir, thermal flow sensor, differential pressure measurement and an automated computerised interface. In enucleated eyes from C57BL/6J mice, the flow-pressure relationship is highly non-linear and is well represented by an empirical power law model that describes the pressure dependence of outflow facility. At zero pressure, the measured flow is indistinguishable from zero, confirming the absence of any significant pressure independent flow in enucleated eyes. Comparison with the commonly used 2-parameter linear outflow model reveals that inappropriate application of a linear fit to a non-linear flow-pressure relationship introduces considerable errors in the estimation of outflow facility and leads to the false impression of pressure-independent outflow. Data from a population of enucleated eyes from C57BL/6J mice show that outflow facility is best described by a lognormal distribution, with 6-fold variability between individuals, but with relatively tight correlation of facility between fellow eyes. iPerfusion represents a platform technology to accurately and robustly characterise the flow-pressure relationship in enucleated mouse eyes for the purpose of glaucoma research and with minor modifications, may be applied

  20. Reducing energy consumption and leakage by active pressure control in a water supply system

    NARCIS (Netherlands)

    Bakker, M.; Rajewicz, T.; Kien, H.; Vreeburg, J.H.G.; Rietveld, L.C.

    2013-01-01

    WTP Gruszczyn supplies drinking water to a part of the city of Pozna?, in the Midwest of Poland. For the optimal automatic pressure control of the clear water pumping station, nine pressure measuring points were installed in the distribution network, and an active pressure control model was

  1. Optimization of perfusion studies using Atropine

    International Nuclear Information System (INIS)

    Alvarado, A.N.; Valle, V.M.; Montoya, M.J.; Eskenazi, E.S.; Montiel, M.L.; Cueto, C.C.

    2002-01-01

    The studies of myocardial perfusion require an adequate stress; exercise or pharmacological. Every day, more pharmacological studies are performed, specially in some group of patients (women, AMI, etc). There some drugs that are used for this purpose, as adenosine and dobutamine. However, their cost and the lack of availability and infrastructure in our country do not allow there routinely use. We performed dipyridamol as a pharmacological stress, however in some patients there is a doubt regarding if the pharmacological effect was adequate. Atropine is a drug that is frequently used for different purpose and it is well know its tachycardic response. We present and alternative technique, using dipyridamol-atropine as a protocol of stress perfusion study. Our goal was to correlate the standard dipyridamol -thallium perfusion study and the dipyridamol -atropine-perfusion in patients with chronic coronary disease. We evaluated 6 patients (5 males) with stable angina and chronic coronary disease. A standard dipyridamol-thallium study was performed in all of them. Dipyridamole was administered intravenously at a rate of 0.14 mg/kg/min over 6 min for a total of 0.84 mg/kg body weight. Blood pressure, heart rate, EKG and symptoms were monitored before, during and after the pharmacological infusion. Two minutes after the infusion was completed, the radiotracer was injected intravenously. In the next 6 months, without any modification of the clinical situation (symptoms and therapy) a new dipyridamol study was performed, using 1 mg of atropine after the administration of dipyridamol. There were no differences in the collateral effects and we observed and average increase of 30% in the heart rate in relation with the study using dipyridamol alone. The addition of atropine to the standard dipyridamol perfusion study is safe, cheaper and improved the detection of perfusion defects in patients with coronary artery disease

  2. Compression therapy in mixed ulcers increases venous output and arterial perfusion.

    Science.gov (United States)

    Mosti, Giovanni; Iabichella, Maria Letizia; Partsch, Hugo

    2012-01-01

    This study was conducted to define bandage pressures that are safe and effective in treating leg ulcers of mixed arterial-venous etiology. In 25 patients with mixed-etiology leg ulcers who received inelastic bandages applied with pressures from 20 to 30, 31 to 40, and 41 to 50 mm Hg, the following measurements were performed before and after bandage application to ensure patient safety throughout the investigation: laser Doppler fluxmetry (LDF) close to the ulcer under the bandage and at the great toe, transcutaneous oxygen pressure (TcPo(2)) on the dorsum of the foot, and toe pressure. Ejection fraction (EF) of the venous pump was performed to assess efficacy on venous hemodynamics. LDF values under the bandages increased by 33% (95% confidence interval [CI], 17-48; P pressure ranges applied. At toe level, a significant decrease in flux of -20% (95% CI, -48 to 9; P bandage pressure >41 mm Hg. Toe pressure values and TcPo(2) showed a moderate increase, excluding a restriction to arterial perfusion induced by the bandages. Inelastic bandages were highly efficient in improving venous pumping function, increasing the reduced ejection fraction by 72% (95% CI, 50%-95%; P pressure of 21 to 30 mm Hg and by 103% (95% CI, 70%-128%; P ulceration, an ankle-brachial pressure index >0.5 and an absolute ankle pressure of >60 mm Hg, inelastic compression of up to 40 mm Hg does not impede arterial perfusion but may lead to a normalization of the highly reduced venous pumping function. Such bandages are therefore recommended in combination with walking exercises as the basic conservative management for patients with mixed leg ulcers. Copyright © 2012 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.

  3. Evaluating optimal superficial limb perfusion at different angles using non-invasive micro-lightguide spectrophotometry.

    Science.gov (United States)

    Darmanin, Geraldine; Jaggard, Matthew; Hettiaratchy, Shehan; Nanchahal, Jagdeep; Jain, Abhilash

    2013-06-01

    It is common practice to elevate the limbs postoperatively to reduce oedema and hence optimise perfusion and facilitate rehabilitation. However, elevation may be counterproductive as it reduces the mean perfusion pressure. There are no clear data on the optimal position of the limbs even in normal subjects. The optimal position of limbs was investigated in 25 healthy subjects using a non-invasive micro-lightguide spectrophotometry system "O2C", which indirectly measures skin and superficial tissue perfusion through blood flow, oxygen saturation and relative haemoglobin concentration. We found a reduction in skin and superficial tissue blood flow of 17% (p=0.0001) on arm elevation (180° shoulder flexion) as compared to heart level and an increase in skin and superficial tissue blood flow of 25% (p=0.02) on forearm elevation of 45°. Lower limb skin and superficial tissue blood flow decreased by 15% (p=0.004) on elevation to 47 cm and by 70% on dependency (p=0.0001) compared to heart level. However, on elevation of the lower limb there was also a 28% reduction in superficial venous pooling (p=0.0001) compared to heart level. In the normal limb, the position for optimal superficial perfusion of the upper limb is with the arm placed at heart level and forearm at 45°. In the lower limb the optimal position for superficial perfusion would be at heart level. However, some degree of elevation may be useful if there is an element of venous congestion. Copyright © 2013 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  4. Consideration of the Intracranial Pressure Threshold Value for the Initiation of Traumatic Brain Injury Treatment: A Xenon CT and Perfusion CT Study.

    Science.gov (United States)

    Honda, Mitsuru; Ichibayashi, Ryo; Suzuki, Ginga; Yokomuro, Hiroki; Seiki, Yoshikatsu; Sase, Shigeru; Kishi, Taichi

    2017-12-01

    Monitoring of intracranial pressure (ICP) is considered to be fundamental for the care of patients with severe traumatic brain injury (TBI) and is routinely used to direct medical and surgical therapy. Accordingly, some guidelines for the management of severe TBI recommend that treatment be initiated for ICP values >20 mmHg. However, it remained to be accounted whether there is a scientific basis to this instruction. The purpose of the present study was to clarify whether the basis of ICP values >20 mmHg is appropriate. We retrospectively reviewed 25 patients with severe TBI who underwent neuroimaging during ICP monitoring within the first 7 days. We measured cerebral blood flow (CBF), mean transit time (MTT), cerebral blood volume (CBV), and ICP 71 times within the first 7 days. Although the CBF, MTT, and CBV values were not correlated with the ICP value at ICP values ≤20 mmHg, the CBF value was significantly negatively correlated with the ICP value (r = -0.381, P values >20 mmHg. The MTT value was also significantly positively correlated with the ICP value (r = 0.638, P values >20 mmHg. The cerebral circulation disturbance increased with the ICP value. We demonstrated the cerebral circulation disturbance at ICP values >20 mmHg. This study suggests that an ICP >20 mmHg is the threshold to initiate treatments. An active treatment intervention would be required for severe TBI when the ICP was >20 mmHg.

  5. Perfusion lung scintigraphy in primary pulmonary hypertension

    International Nuclear Information System (INIS)

    Ogawa, Y.; Hayashida, K.; Uehara, T.; Shimonagata, T.; Nishimura, T.; Osaka Univ., Suita

    1993-01-01

    15 cases of primary pulmonary hypertension were classified into two groups by patterns of perfusion lung scintigraphy. Perfusion scintigrams showed multiple, small, ill-defined defects (mottled + ve) pattern in eight cases, and the remaining seven cases had a normal (mottled - ve) pattern. The mean pulmonary arterial pressure in patients with a mottled pattern (54 ± 10 mmHg) was higher than in those with a normal pattern (42 ± 9 mmHg, p < 0.05). There were no significant differences between the two groups in right ventricular ejection fraction, partial pressures of oxygen in the arterial blood or alveolo-arterial oxygen difference. All the patients with a mottled pattern died within 2 years following the lung scintigraphy. There was a significant difference in the survival curves between the two groups. (author)

  6. Reverse ventilation--perfusion mismatch

    International Nuclear Information System (INIS)

    Palmaz, J.C.; Barnett, C.A.; Reich, S.B.; Krumpe, P.E.; Farrer, P.A.

    1984-01-01

    Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a ''reversed'' ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients

  7. Electrochemical Testing of Gas Tungsten Arc Welded and Reduced Pressure Electron Beam Welded Alloy 22

    International Nuclear Information System (INIS)

    Day, S D; Wong, F G; Gordon, S R; Wong, L L; Rebak, R B

    2006-01-01

    Alloy 22 (N06022) is the material selected for the fabrication of the outer shell of the nuclear waste containers for the Yucca Mountain high-level nuclear waste repository site. A key technical issue in the waste package program has been the integrity of the container weld joints. The currently selected welding process for fabricating and sealing the containers is the traditional gas tungsten arc welding (GTAW) or TIG method. An appealing faster alternative technique is reduced pressure electron beam (RPEB) welding. It was of interest to compare the corrosion properties of specimens prepared using both types of welding techniques. Standard electrochemical tests were carried on GTAW and RPEB welds as well as on base metal (non-welded) to determine their relative corrosion behavior in simulated concentrated water (SCW) at 90 C (alkaline), 1 M HCl at 60 C (acidic) and 1 M NaCl at 90 C (neutral) solutions. Results show that for all practical purposes, the three tested materials had the same electrochemical behavior in the three tested electrolytes

  8. Diet and exercise training reduce blood pressure and improve autonomic modulation in women with prehypertension.

    Science.gov (United States)

    Sales, Allan R K; Silva, Bruno M; Neves, Fabricia J; Rocha, Natália G; Medeiros, Renata F; Castro, Renata R T; Nóbrega, Antonio C L

    2012-09-01

    Despite mortality from heart disease has been decreasing, the decline in death in women remains lower than in men. Hypertension (HT) is a major risk factor for cardiovascular disease. Therefore, approaches to prevent or delay the onset of HT would be valuable in women. Given this background, we investigated the effect of diet and exercise training on blood pressure (BP) and autonomic modulation in women with prehypertension (PHT). Ten women with PHT (39 ± 6 years, mean ± standard deviation) and ten with normotension (NT) (35 ± 11 years) underwent diet and exercise training for 12 weeks. Autonomic modulation was assessed through heart rate (HR) and systolic BP (SBP) variability, using time and frequency domain analyses. At preintervention, women with PHT had higher SBP (PHT: 128 ± 7 vs. NT: 111 ± 6 mmHg, p 0.05). Moreover, reduction in SBP was associated with augmentation in SDNN (r = -0.46, p diet and exercise training reduced SBP in women with PHT, and this was associated with augmentation in parasympathetic and probably reduction in sympathetic cardiac modulation.

  9. Electrochemical Testing of Gas Tungsten ARC Welded and Reduced Pressure Electron Beam Welded Alloy 22

    International Nuclear Information System (INIS)

    S. Daniel Day; Frank M.G. Wong; Steven R. Gordon; Lana L. Wong; Raul B. Rebak

    2006-01-01

    Alloy 22 (N06022) is the material selected for the fabrication of the outer shell of the nuclear waste containers for the Yucca Mountain high-level nuclear waste repository site. A key technical issue in the waste package program has been the integrity of the container weld joints. The currently selected welding process for fabricating and sealing the containers is the traditional gas tungsten arc welding (GTAW) or TIC method. An appealing faster alternative technique is reduced pressure electron beam (RPEB) welding. It was of interest to compare the corrosion properties of specimens prepared using both types of welding techniques. Standard electrochemical tests were carried on GTAW and RPEB welds as well as on base metal (non-welded) to determine their relative corrosion behavior in simulated concentrated water (SCW) at 90 C (alkaline), 1 M HCI at 60 C (acidic) and 1 M NaCl at 90 C (neutral) solutions. Results show that for all practical purposes, the three tested materials had the same electrochemical behavior in the three tested electrolytes

  10. Usefulness of the convexity apparent hyperperfusion sign in 123I-iodoamphetamine brain perfusion SPECT for the diagnosis of idiopathic normal pressure hydrocephalus.

    Science.gov (United States)

    Ohmichi, Takuma; Kondo, Masaki; Itsukage, Masahiro; Koizumi, Hidetaka; Matsushima, Shigenori; Kuriyama, Nagato; Ishii, Kazunari; Mori, Etsuro; Yamada, Kei; Mizuno, Toshiki; Tokuda, Takahiko

    2018-03-16

    OBJECTIVE The gold standard for the diagnosis of idiopathic normal pressure hydrocephalus (iNPH) is the CSF removal test. For elderly patients, however, a less invasive diagnostic method is required. On MRI, high-convexity tightness was reported to be an important finding for the diagnosis of iNPH. On SPECT, patients with iNPH often show hyperperfusion of the high-convexity area. The authors tested 2 hypotheses regarding the SPECT finding: 1) it is relative hyperperfusion reflecting the increased gray matter density of the convexity, and 2) it is useful for the diagnosis of iNPH. The authors termed the SPECT finding the convexity apparent hyperperfusion (CAPPAH) sign. METHODS Two clinical studies were conducted. In study 1, SPECT was performed for 20 patients suspected of having iNPH, and regional cerebral blood flow (rCBF) of the high-convexity area was examined using quantitative analysis. Clinical differences between patients with the CAPPAH sign (CAP) and those without it (NCAP) were also compared. In study 2, the CAPPAH sign was retrospectively assessed in 30 patients with iNPH and 19 healthy controls using SPECT images and 3D stereotactic surface projection. RESULTS In study 1, rCBF of the high-convexity area of the CAP group was calculated as 35.2-43.7 ml/min/100 g, which is not higher than normal values of rCBF determined by SPECT. The NCAP group showed lower cognitive function and weaker responses to the removal of CSF than the CAP group. In study 2, the CAPPAH sign was positive only in patients with iNPH (24/30) and not in controls (sensitivity 80%, specificity 100%). The coincidence rate between tight high convexity on MRI and the CAPPAH sign was very high (28/30). CONCLUSIONS Patients with iNPH showed hyperperfusion of the high-convexity area on SPECT; however, the presence of the CAPPAH sign did not indicate real hyperperfusion of rCBF in the high-convexity area. The authors speculated that patients with iNPH without the CAPPAH sign, despite showing

  11. A low-carbohydrate/high-fat diet reduces blood pressure in spontaneously hypertensive rats without deleterious changes in insulin resistance

    OpenAIRE

    Bosse, John D.; Lin, Han Yi; Sloan, Crystal; Zhang, Quan-Jiang; Abel, E. Dale; Pereira, Troy J.; Dolinsky, Vernon W.; Symons, J. David; Jalili, Thunder

    2013-01-01

    Previous studies reported that diets high in simple carbohydrates could increase blood pressure in rodents. We hypothesized that the converse, a low-carbohydrate/high-fat diet, might reduce blood pressure. Six-week-old spontaneously hypertensive rats (SHR; n = 54) and Wistar-Kyoto rats (WKY; n = 53, normotensive control) were fed either a control diet (C; 10% fat, 70% carbohydrate, 20% protein) or a low-carbohydrate/high-fat diet (HF; 20% carbohydrate, 60% fat, 20% protein). After 10 wk, SHR-...

  12. Hepatic artery perfusion imaging

    International Nuclear Information System (INIS)

    Thrall, J.H.; Gyves, J.W.; Ziessman, H.A.; Ensminger, W.D.

    1985-01-01

    Organ and region-selective intra-arterial chemotherapy have been used for more than two decades to treat malignant neoplasms in the extremities, head and neck region, pelvis, liver, and other areas. Substantial evidence of improved response to regional chemotherapy now exists, but there are stringent requirements for successful application of the regional technique. First, the chemotherapeutic agent employed must have appropriate pharmacokinetic and pharmacodynamic properties. Second, the drug must be reliably delivered to the tumor-bearing area. This typically requires an arteriographic assessment of the vascular supply of the tumor, followed by placement of a therapeutic catheter and confirmation that the ''watershed'' perfusion distribution from the catheter truly encompasses the tumor. Optimal catheter placement also minimizes perfusion of nontarget organs. Radionuclide perfusion imaging with technetium 99m-labeled particles, either microspheres or macroaggregates of albumin, has become the method of choice for making these assessments. Catheter placement itself is considered by many to represent a type of ''therapeutic'' intervention. However, once the catheter is in the hepatic artery the radionuclide perfusion technique can be used to assess adjunctive pharmacologic maneuvers designed to further exploit the regional approach to chemotherapy. This chapter presents the technetium Tc 99m macroaggregated albumin method for assessing catheter placement and the pharmacokinetic rationale for regional chemotherapy, and discusses two promising avenues for further intervention

  13. Extremity perfusion for sarcoma

    NARCIS (Netherlands)

    Hoekstra, Harald Joan

    2008-01-01

    For more than 50 years, the technique of extremity perfusion has been explored in the limb salvage treatment of local, recurrent, and multifocal sarcomas. The "discovery" of tumor necrosis factor-or. in combination with melphalan was a real breakthrough in the treatment of primarily irresectable

  14. Isolated limb perfusion.

    Science.gov (United States)

    Gillespie, Rosalyn; Chantier, Nariane

    1994-12-08

    Growing concern over the rising incidence of malignant melanoma has brought about a need for information on this disorder and the treatment available. Isolated limb perfusion is a relatively new technique used in only a few hospitals. An increased knowledge base will lead to a better understanding of the nursing care required and to a more in-depth care plan.

  15. Complete inhibition of creatine kinase in isolated perfused rat hearts

    International Nuclear Information System (INIS)

    Fossel, E.T.; Hoefeler, H.

    1987-01-01

    Transient exposure of an isolated isovolumic perfused rat heart to low concentrations (0.5 mM) of perfusate-born iodoacetamide resulted in complete inhibition of creatine kinase and partial inhibition of glyceraldehyde-3-phosphate dehydrogenase in the heart. At low levels of developed pressure, hearts maintained mechanical function, ATP, and creatine phosphate levels at control values. However, iodoacetamide-inhibited hearts were unable to maintain control values of end diastolic pressure or peak systolic pressure as work load increased. Global ischemia resulted in loss of all ATP without loss of creatine phosphate, indicating lack of active creatine kinase. These results indicate that isovolumic perfused rat hearts are able to maintain normal function and normal levels of high-energy phosphates without active creatine kinase at low levels of developed pressure. 31 P-NMR of the heart was carried out

  16. Reducing risk of pressure sores: effects of watch prompts and alarm avoidance on wheelchair push-ups.

    Science.gov (United States)

    White, G W; Mathews, R M; Fawcett, S B

    1989-01-01

    People who use wheelchairs are at risk for developing pressure sores. Regular pressure relief, in the form of a wheelchair push-up, is one way to reduce the likelihood of pressure sores. We examined the effects of antecedent (i.e., instructions, audible prompts) and consequent (i.e., alarm avoidance) events on wheelchair push-ups, using a multiple baseline analysis with 2 participants with spina bifida. Results suggest that the combined procedure was more effective than either antecedent or consequent events alone, and there is some evidence suggesting maintenance of effects over time. PMID:2793635

  17. Reducing Fatigue Loading Due to Pressure Shift in Discrete Fluid Power Force Systems

    DEFF Research Database (Denmark)

    Hansen, Anders Hedegaard; Pedersen, Henrik Clemmensen

    2016-01-01

    power force system. The current paper investigates the correlation between pressure oscillations in the cylinder chambers and valve flow in the manifold. Furthermore, the correlation between the pressure shifting time and the pressure overshoot is investigated. The study therefore focus on how to shape......Discrete Fluid Power Force Systems is one of the topologies gaining focus in the pursuit of lowering energy losses in fluid power transmission systems. The cylinder based Fluid Power Force System considered in this article is constructed with a multi-chamber cylinder, a number of constant pressure...... oscillations in the cylinder chamber, especially for systems with long connections between the cylinder and the valve manifold. Hose pressure oscillations will induce oscillations in the produced piston force. Hence, pressure oscillations may increase the fatigue loading on systems employing a discrete fluid...

  18. Sulphate chemistry under pressurized oxidizing, reducing and fluctuating conditions; Sulfatkemi under trycksatta oxiderande, reducerande och fluktuerande foerhaallanden

    Energy Technology Data Exchange (ETDEWEB)

    Hupa, M.; Yrjas, P.; Backman, P. [Aabo Akademi, Turku (Finland). Combustion Chemistry Research Group

    1997-10-01

    In the literature it has been reported that sulfur capture with limestone (CaCO{sub 3}) under atmospheric fluidized bed combustion conditions reaches a maximum at about 850 deg C. Previously, the maximum has been attributed to the sintering of sorbent particles which decreases the reactive surface area. Lately, also another explanation has been reported. In this case the sulfur capture decrease at higher temperatures was concluded to be due to fluctuating oxidizing/reducing conditions in the atmospheric combustor. In this work the influence of alternating oxidizing/reducing conditions on SO{sub 2} capture at atmospheric and elevated pressure (15 bar) has been studied. In the pressurized case, the CO{sub 2} partial pressure was kept high enough to prevent CaCO{sub 3} from calcining and therefore the CaSO{sub 4} would not form CaO but CaCO{sub 3} under reducing conditions. The experiments were done with a pressurized TGA by periodically changing the gas environment between oxidizing (O{sub 2}. SO{sub 2}, CO{sub 2} and N{sub 2}) and slightly reducing (CO, SO{sub 2}, CO{sub 2} and N{sub 2}) gas mixtures at different temperatures. The results from the experiments showed that under normal pressure and slightly reducing conditions CaO formation from CaSO{sub 4} increased with temperature as expected. However, no significant amounts of CaCO{sub 3} were formed from CaSO{sub 4} at elevated pressure. It was also concluded that since the formation of CaO from CaSO{sub 4} was relatively slow it could not explain the sharp sulfur capture maximum at about 850 deg C. Therefore, it was assumed that the strongly reducing zones, where CaS thermodynamically is the stable compound, play a more important role concerning the sulfur capture in fluidized bed combustors. (orig.)

  19. Perfusion-weighted MR imaging of uterine leiomyoma

    Energy Technology Data Exchange (ETDEWEB)

    Takase, Hiroyasu; Munechika, Hirotsugu [Showa Univ., Tokyo (Japan). School of Medicine

    2001-06-01

    Serial images of uterine leiomyoma in gradient-echo, echo-planar, magnetic resonance imaging were taken to draw a {delta}R2{sup *} curve after intravenous bolus injection of Gd-DTPA. The {delta}R2{sup *} integral was calculated from a {delta}R2{sup *} curve to have relative perfusion of uterine leiomyoma. We then, evaluated the amount of perfusion correlated with MR findings, size and number of leiomyoma or the clinical symptoms and established that perfusion was correlated positively with the findings of T2 weighted images and clinical symptoms but not with other MR findings or size and number of leiomyoma. In conclusion, we presumed that the clinical symptoms could be reduced by decreasing of an amount of perfusion of uterine leiomyoma in some means. However, it remained uncertain why severe clinical symptoms were associated with a high amount of perfusion in uterine leiomyomas. (author)

  20. Pressure reducing capacity of felt: a feasibility study using a new portable system with thin sensors.

    Science.gov (United States)

    Deschamps, Kevin; Messier, Benjamin

    2015-03-01

    Pressure redistribution and off-loading is a vital component in the management of the foot in diabetes. In the present study, a new portable system encompassing thin piezoresistors was tested for clinical utility and efficacy with respect to a commonly used pressure relieving dressing for the foot in diabetes. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  1. Chronic renin inhibition lowers blood pressure and reduces upright muscle sympathetic nerve activity in hypertensive seniors

    Science.gov (United States)

    Okada, Yoshiyuki; Jarvis, Sara S; Best, Stuart A; Bivens, Tiffany B; Adams-Huet, Beverley; Levine, Benjamin D; Fu, Qi

    2013-01-01

    Cardiovascular risk remains high in patients with hypertension even with adequate blood pressure (BP) control. One possible mechanism may be sympathetic activation via the baroreflex. We tested the hypothesis that chronic inhibition of renin reduces BP without sympathetic activation, but diuresis augments sympathetic activity in elderly hypertensives. Fourteen patients with stage-I hypertension (66 ± 5 (SD) years) were treated with a direct renin inhibitor, aliskiren (n= 7), or a diuretic, hydrochlorothiazide (n= 7), for 6 months. Muscle sympathetic nerve activity (MSNA), BP, direct renin and aldosterone were measured during supine and a graded head-up tilt (HUT; 5 min 30° and 20 min 60°), before and after treatment. Sympathetic baroreflex sensitivity (BRS) was assessed. Both groups had similar BP reductions after treatment (all P < 0.01), while MSNA responses were different between hydrochlorothiazide and aliskiren (P= 0.006 pre/post × drug). Both supine and upright MSNA became greater after hydrochlorothiazide treatment (supine, 72 ± 18 post vs. 64 ± 15 bursts (100 beats)−1 pre; 60° HUT, 83 ± 10 vs. 78 ± 13 bursts (100 beats)−1; P= 0.002). After aliskiren treatment, supine MSNA remained unchanged (69 ± 13 vs. 64 ± 8 bursts (100 beats)−1), but upright MSNA was lower (74 ± 15 vs. 85 ± 10 bursts (100 beats)−1; P= 0.012 for pre/post × posture). Direct renin was greater after both treatments (both P < 0.05), while upright aldosterone was greater after hydrochlorothiazide only (P= 0.002). The change in upright MSNA by the treatment was correlated with the change of aldosterone (r= 0.74, P= 0.002). Upright sympathetic BRS remained unchanged after either treatment. Thus, chronic renin inhibition may reduce upright MSNA through suppressed renin activity, while diuresis may evoke sympathetic activation via the upregulated renin–angiotensin–aldosterone system, without changing intrinsic sympathetic baroreflex function in elderly hypertensive

  2. What role can nurse leaders play in reducing the incidence of pressure sores?

    Science.gov (United States)

    Wurster, Joan

    2007-01-01

    Pressure sores have plagued the nursing profession for many years as a major health care problem in terms of a patient's suffering and financial cost. Pressure sores are increasingly common in hospitalized patients in the United States with a 63% increase from 1993 to 2003. The nurse leader is accountable for the occurrence of pressure sores, a nurse-sensitive indicator, by a scorecard which is benchmarked against other facilities. The nurse leader must take a systematic approach in the prevention of pressure sores, with the strategy being consistent and motivating to the staff in order to improve patient outcome. The chief nursing officer, the unit manager, and the bedside nurse must all collaborate to prevent tissue injury in patients at risk for developing pressure sores and to promote wound healing in patients with existing breakdown.

  3. Reduced injection pressures using a compressed air injection technique (CAIT): an in vitro study.

    Science.gov (United States)

    Tsui, Ban C H; Knezevich, Mark P; Pillay, Jennifer J

    2008-01-01

    High injection pressures have been associated with intraneural injection and persistent neurological injury in animals. Our objective was to test whether a reported simple compressed air injection technique (CAIT) would limit the generation of injection pressures to below a suggested 1,034 mm Hg limit in an in vitro model. After ethics board approval, 30 consenting anesthesiologists injected saline into a semiclosed system. Injection pressures using 30 mL syringes connected to a 22 gauge needle and containing 20 mL of saline were measured for 60 seconds using: (1) a typical "syringe feel" method, and (2) CAIT, thereby drawing 10 mL of air above the saline and compressing this to 5 mL prior to and during injections. All anesthesiologists performed the syringe feel method before introduction and demonstration of CAIT. Using CAIT, no anesthesiologist generated pressures above 1,034 mm Hg, while 29 of 30 produced pressures above this limit at some time using the syringe feel method. The mean pressure using CAIT was lower (636 +/- 71 vs. 1378 +/- 194 mm Hg, P = .025), and the syringe feel method resulted in higher peak pressures (1,875 +/- 206 vs. 715 +/- 104 mm Hg, P = .000). This study demonstrated that CAIT can effectively keep injection pressures under 1,034 mm Hg in this in vitro model. Animal and clinical studies will be needed to determine whether CAIT will allow objective, real-time pressure monitoring. If high pressure injections are proven to contribute to nerve injury in humans, this technique may have the potential to improve the safety of peripheral nerve blocks.

  4. Brief pressure overload of the left ventricle reduces myocardial infarct size via activation of protein kinase C.

    Science.gov (United States)

    Tang, Chia-Yu; Lai, Chang-Chi; Chiang, Shu-Chiung; Tseng, Kuo-Wei; Huang, Cheng-Hsiung

    2015-09-01

    We have previously reported that brief pressure overload of the left ventricle reduced myocardial infarct (MI) size. However, the role of protein kinase C (PKC) remains uncertain. In this study, we investigated whether pressure overload reduces MI size by activating PKC. MI was induced by a 40-minute occlusion of the left anterior descending coronary artery and a 3-hour reperfusion in anesthetized Sprague-Dawley rats. MI size was determined using triphenyl tetrazolium chloride staining. Brief pressure overload was achieved by two 10-minute partial snarings of the ascending aorta, raising the systolic left ventricular pressure 50% above the baseline value. Ischemic preconditioning was elicited by two 10-minute coronary artery occlusions and 10-minute reperfusions. Dimethyl sulfoxide (vehicle) or calphostin C (0.1 mg/kg, a specific inhibitor of PKC) was administered intravenously as pretreatment. The MI size, expressed as the percentage of the area at risk, was significantly reduced in the pressure overload group and the ischemic preconditioning group (19.0 ± 2.9% and 18.7 ± 3.0% vs. 26.1 ± 2.6% in the control group, where p overload and ischemic preconditioning (25.2 ± 2.4% and 25.0 ± 2.3%, where p overload of the left ventricle reduced MI size. Since calphostin C significantly limited the decrease of MI size, our results suggested that brief pressure overload reduces MI size via activation of PKC. Copyright © 2015. Published by Elsevier Taiwan.

  5. Temperature and pressure adaptation of a sulfate reducer from the deep subsurface

    Directory of Open Access Journals (Sweden)

    Katja eFichtel

    2015-10-01

    Full Text Available Microbial life in deep marine subsurface faces increasing temperatures and hydrostatic pressure with depth. In this study, we have examined growth characteristics and temperature-related adaptation of the Desulfovibrio indonesiensis strain P23 to the in situ pressure of 30 MPa. The strain originates from the deep subsurface of the eastern flank of the Juan de Fuca Ridge (IODP Site U1301. The organism was isolated at 20 °C and atmospheric pressure from ~61 °C-warm sediments approximately five meters above the sediment-basement interface. In comparison to standard laboratory conditions (20 °C and 0.1 MPa, faster growth was recorded when incubated at in situ pressure and high temperature (45 °C, while cell filamentation was induced by further compression. The maximum growth temperature shifted from 48°C at atmospheric pressure to 50°C under high-pressure conditions. Complementary cellular lipid analyses revealed a two-step response of membrane viscosity to increasing temperature with an exchange of unsaturated by saturated fatty acids and subsequent change from branched to unbranched alkyl moieties. While temperature had a stronger effect on the degree of fatty acid saturation and restructuring of main phospholipids, pressure mainly affected branching and length of side chains. The simultaneous decrease of temperature and pressure to ambient laboratory conditions allowed the cultivation of our moderately thermophilic strain. This may in turn be one key to a successful isolation of microorganisms from the deep subsurface adapted to high temperature and pressure.

  6. Low internal pressure in femtoliter water capillary bridges reduces evaporation rates.

    Science.gov (United States)

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

    2016-03-01

    Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges.

  7. Reducing non value adding aluminium alloy in production of parts through high pressure die casting

    CSIR Research Space (South Africa)

    Pereira, MFVT

    2010-10-01

    Full Text Available in the cast part feed system, including overflows. CSIR intends using the results of this research for further development and application of high temperature die construction materials in high pressure die casting processes of light metal alloys...

  8. Low internal pressure in femtoliter water capillary bridges reduces evaporation rates

    Science.gov (United States)

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

    2016-01-01

    Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges. PMID:26928329

  9. A glucagon-like peptide-1 receptor agonist reduces intracranial pressure in a rat model of hydrocephalus

    DEFF Research Database (Denmark)

    Botfield, Hannah F; Uldall, Maria S; Westgate, Connar S J

    2017-01-01

    Current therapies for reducing raised intracranial pressure (ICP) under conditions such as idiopathic intracranial hypertension or hydrocephalus have limited efficacy and tolerability. Thus, there is a pressing need to identify alternative drugs. Glucagon-like peptide-1 receptor (GLP-1R) agonists...

  10. Positioning bedridden patients to reduce interface pressures over the sacrum and great trochanter.

    Science.gov (United States)

    Yoshikawa, Y; Maeshige, N; Sugimoto, M; Uemura, M; Noguchi, M; Terashi, H

    2015-07-01

    In this study, we evaluated the effect of hip-joint rotation on the interface pressure over the sacrum and greater trochanter with a new protocol for positioning of bedridden elderly patients. The interface pressure values over the sacrum and greater trochanter in bedridden patients were evaluated. These were collected in the supine position, 90° lateral position, and 30° and 40° laterally inclined positions with external rotation or neutral positioning of the hip joint. Each interface pressure was assessed with a device measuring pressure distribution, after which, the peak pressure index (PPI) was calculated. In the 17 patients examined, the PPI over the sacrum in the supine position was significantly greater than that in other positions. In the 30° and 40° laterally inclined positions, the PPIs over the greater trochanter were significantly lower in the neutral position of the hip joint compared with those in the external rotation position. Our findings revealed the effects of hip-joint rotation on the interface pressure for the greater trochanter, possibly due to the increased distance between the greater trochanter and the sacrum caused by neutral position of the hip joint. The results demonstrate that it is to best place the hip joint in a neutral position when the legs are in contact with the bed in order to distribute the pressure over the greater trochanter in the 30° and 40° laterally inclined positions. These results can be applied to the clinical setting to improve patient positioning and decrease pressure ulcers. The authors declare that they have no competing financial interests.

  11. The turn team: a novel strategy for reducing pressure ulcers in the surgical intensive care unit.

    Science.gov (United States)

    Still, Mary D; Cross, Linda C; Dunlap, Martha; Rencher, Rugenia; Larkins, Elizabeth R; Carpenter, David L; Buchman, Timothy G; Coopersmith, Craig M

    2013-03-01

    Pressure ulcers cause significant morbidity and mortality in the surgical intensive care unit (SICU). The purpose of this study was to determine if a dedicated team tasked with turning and repositioning all hemodynamically stable SICU patients could decrease the formation of pressure ulcers. A total of 507 patients in a 20-bed SICU in a university hospital were assessed for pressure ulcers using a point prevalence strategy, between December 2008 and September 2010, before and after implementation of a team tasked with turning and repositioning all hemodynamically stable patients every 2 hours around the clock. At baseline, when frequent turning was encouraged but not required, a total of 42 pressure ulcers were identified in 278 patients. After implementation of the turn team, a total of 12 pressure ulcers were identified in 229 patients (p < 0.0001). The preintervention group included 34 stage I and II ulcers and 8 higher stage ulcers. After implementation of the turn team, there were 7 stage I and II ulcers and 5 higher stage ulcers. The average Braden score was 16.5 in the preintervention group and 13.4 in the postintervention group (p = 0.04), suggesting that pressure ulcers were occurring in higher risk patients after implementation of the turn team. A team dedicated to turning SICU patients every 2 hours dramatically decreased the incidence of pressure ulcers. The majority of stage I and stage II ulcers appear to be preventable with an aggressive intervention aimed at pressure ulcer prevention. Copyright © 2013 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  12. Captopril improves tumor nanomedicine delivery by increasing tumor blood perfusion and enlarging endothelial gaps in tumor blood vessels.

    Science.gov (United States)

    Zhang, Bo; Jiang, Ting; Tuo, Yanyan; Jin, Kai; Luo, Zimiao; Shi, Wei; Mei, Heng; Hu, Yu; Pang, Zhiqing; Jiang, Xinguo

    2017-12-01

    Poor tumor perfusion and unfavorable vessel permeability compromise nanomedicine drug delivery to tumors. Captopril dilates blood vessels, reducing blood pressure clinically and bradykinin, as the downstream signaling moiety of captopril, is capable of dilating blood vessels and effectively increasing vessel permeability. The hypothesis behind this study was that captopril can dilate tumor blood vessels, improving tumor perfusion and simultaneously enlarge the endothelial gaps of tumor vessels, therefore enhancing nanomedicine drug delivery for tumor therapy. Using the U87 tumor xenograft with abundant blood vessels as the tumor model, tumor perfusion experiments were carried out using laser Doppler imaging and lectin-labeling experiments. A single treatment of captopril at a dose of 100 mg/kg significantly increased the percentage of functional vessels in tumor tissues and improved tumor blood perfusion. Scanning electron microscopy of tumor vessels also indicated that the endothelial gaps of tumor vessels were enlarged after captopril treatment. Immunofluorescence-staining of tumor slices demonstrated that captopril significantly increased bradykinin expression, possibly explaining tumor perfusion improvements and endothelial gap enlargement. Additionally, imaging in vivo, imaging ex vivo and nanoparticle distribution in tumor slices indicated that after a single treatment with captopril, the accumulation of 115-nm nanoparticles in tumors had increased 2.81-fold with a more homogeneous distribution pattern in comparison to non-captopril treated controls. Finally, pharmacodynamics experiments demonstrated that captopril combined with paclitaxel-loaded nanoparticles resulted in the greatest tumor shrinkage and the most extensive necrosis in tumor tissues among all treatment groups. Taken together, the data from the present study suggest a novel strategy for improving tumor perfusion and enlarging blood vessel permeability simultaneously in order to improve

  13. Perfusion lung scintigraphy in primary pulmonary hypertension

    International Nuclear Information System (INIS)

    Ogawa, Yoji; Nishimura, Tsunehiko; Kumita, Shin-ichirou; Hayashida, Kohei; Uehara, Toshiisa; Shimonagata, Tsuyoshi; Ohno, Akira

    1991-01-01

    Fifteen cases with primary pulmonary hypertension (PPH) were classified into two groups by using the perfusion lung scan pattern. Eight cases had multiple, small, ill-defined defects (mottled pattern), and remaining seven cases had no mottled pattern. These two groups were compared with mean pulmonary arterial pressure (mean PAP), right ventricular ejection fraction (RVEF), blood gas at room air (PaO 2 ), and alveolar-arterial O 2 difference (A-aDo 2 ). The cases with mottled pattern showed a significant increase in mean PAP. There were no significant differences in RVEF, PaO 2 , and A-aDo 2 , between the groups. The survival rate of the patients with mottled pattern was significantly lower than that without mottled pattern (p<0.05). We concluded that perfusion lung scan is very useful for evaluation of the prognosis in primary pulmonary hypertension. (author)

  14. Brownfield management opportunities to reduce the back pressure effects on the gas wells

    Directory of Open Access Journals (Sweden)

    Stefanescu Dan-Paul

    2017-01-01

    Full Text Available Gas mature fields are associated with challenges to optimize the hydrocarbon flow from reservoir to the sales point in a cost effective manner due to declining well productivity. Laslau Mare field is a mature gas field in Transylvanian basin (Mures County developed in 1970s and is producing∼99% methane with low water-gas ratio. As any brown field, the state of depleted reservoir will generate several constraints for gas flow from formation to surface facilities and further to delivery point. During the exploitation has been observed that the operation conditions are facing with unstable pressure in the system due to low demand. Therefore, the back pressure effect will affect the wells in terms of inability to unload the bottomhole accumulated liquids and the reservoir will suffer a higher pressure drawdown. The best fit-for-purpose solution to overcome the above challenges is represented by installation of group compressor. Laslau Mare field has 3 group compressors running and shows positive results, especially when external pressure fluctuates continuously. This paper explain the challenges seen in 2016 in Laslau Mare field with back pressure effects and how the compression overcome them, and also other solutions that should be considered to optimize the well production.

  15. Leakage Reduction in Water Distribution Systems with Efficient Placement and Control of Pressure Reducing Valves Using Soft Computing Techniques

    Directory of Open Access Journals (Sweden)

    A. Gupta

    2017-04-01

    Full Text Available Reduction of leakages in a water distribution system (WDS is one of the major concerns of water industries. Leakages depend on pressure, hence installing pressure reducing valves (PRVs in the water network is a successful techniques for reducing leakages. Determining the number of valves, their locations, and optimal control setting are the challenges faced. This paper presents a new algorithm-based rule for determining the location of valves in a WDS having a variable demand pattern, which results in more favorable optimization of PRV localization than that caused by previous techniques. A multiobjective genetic algorithm (NSGA-II was used to determine the optimized control value of PRVs and to minimize the leakage rate in the WDS. Minimum required pressure was maintained at all nodes to avoid pressure deficiency at any node. Proposed methodology is applied in a benchmark WDS and after using PRVs, the average leakage rate was reduced by 6.05 l/s (20.64%, which is more favorable than the rate obtained with the existing techniques used for leakage control in the WDS. Compared with earlier studies, a lower number of PRVs was required for optimization, thus the proposed algorithm tends to provide a more cost-effective solution. In conclusion, the proposed algorithm leads to more favorable optimized localization and control of PRV with improved leakage reduction rate.

  16. Perfusion based cell culture chips

    DEFF Research Database (Denmark)

    Heiskanen, Arto; Emnéus, Jenny; Dufva, Martin

    2010-01-01

    Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium composition, long term unattended cultures...... and tissue like structuring of the cultures. However, as this chapter illustrates, many issues remain to be identified regarding perfusion cell culture such as design, material choice and how to use these systems before they will be widespread amongst biomedical researchers....

  17. Alternative Shape of Suction Caisson to Reduce Risk of Buckling under high Pressure

    DEFF Research Database (Denmark)

    Madsen, Søren; Andersen, Lars Vabbersgaard; Ibsen, Lars Bo

    2013-01-01

    Using large suction caissons for offshore wind turbines is an upcoming technology also referred to as bucket foundations. During operation the bucket foundation is loaded by a large overturning moment from the wind turbine and the wave loads. However, during installation the bucket is loaded...... cylindrical monopod foundation made of steel. In this paper, an alternative design/shape of the suction caisson, having a smaller risk of buckling under high pressure is presented. The risk of structural buckling is addressed using numerical methods to determine the buckling pressures of the re...

  18. Reducing the pressure drag of a D-shaped bluff body using linear feedback control

    Science.gov (United States)

    Dalla Longa, L.; Morgans, A. S.; Dahan, J. A.

    2017-12-01

    The pressure drag of blunt bluff bodies is highly relevant in many practical applications, including to the aerodynamic drag of road vehicles. This paper presents theory revealing that a mean drag reduction can be achieved by manipulating wake flow fluctuations. A linear feedback control strategy then exploits this idea, targeting attenuation of the spatially integrated base (back face) pressure fluctuations. Large-eddy simulations of the flow over a D-shaped blunt bluff body are used as a test-bed for this control strategy. The flow response to synthetic jet actuation is characterised using system identification, and controller design is via shaping of the frequency response to achieve fluctuation attenuation. The designed controller successfully attenuates integrated base pressure fluctuations, increasing the time-averaged pressure on the body base by 38%. The effect on the flow field is to push the roll-up of vortices further downstream and increase the extent of the recirculation bubble. This control approach uses only body-mounted sensing/actuation and input-output model identification, meaning that it could be applied experimentally.

  19. RCS pressure under reduced inventory conditions following a loss of residual heat removal

    International Nuclear Information System (INIS)

    Palmrose, D.E.; Hughes, E.D.; Johnsen, G.W.

    1992-01-01

    The thermal-hydraulic response of a closed-reactor coolant system to loss of residual heat removal (RHR) cooling is investigated. The processes examined include: core coolant boiling and steam generator reflux condensation, pressure increase on the primary side, heat transfer mechanisms on the steam generator primary and secondary sides, and effects of noncondensible gas on heat transfer processes

  20. [Reduced risk of stroke recurrence due to hypotensive medication, irrespective of the initial blood pressure

    NARCIS (Netherlands)

    Lenders, J.W.M.; Thien, Th.

    2002-01-01

    The 'Perindopril protection against recurrent stroke study' (PROGRESS) demonstrated that for patients with a history of stroke or transient ischaemic attack during the previous 5 years, a blood-pressure-lowering regimen based on the combination of a diuretic and an angiotensin-converting enzyme

  1. Dynamic (4D) CT perfusion offers simultaneous functional and anatomical insights into pulmonary embolism resolution

    Energy Technology Data Exchange (ETDEWEB)

    Mirsadraee, Saeed, E-mail: saeed.mirsadraee@ed.ac.uk [Clinical Research Imaging Centre, Queen' s Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ (United Kingdom); Reid, John H.; Connell, Martin [Clinical Research Imaging Centre, Queen' s Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ (United Kingdom); MacNee, William; Hirani, Nikhil [The Queen' s Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ (United Kingdom); Murchison, John T. [Department of Radiology, Royal Infirmary of Edinburgh, 51 Little France Crescent, Edinburgh EH16 4SA (United Kingdom); Beek, Edwin J. van [Clinical Research Imaging Centre, Queen' s Medical Research Institute, University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ (United Kingdom)

    2016-10-15

    Objective: Resolution and long-term functional effects of pulmonary emboli are unpredictable. This study was carried out to assess persisting vascular bed perfusion abnormalities and resolution of arterial thrombus in patients with recent pulmonary embolism (PE). Methods and materials: 26 Patients were prospectively evaluated by dynamic (4D) contrast enhanced CT perfusion dynamic pulmonary CT perfusion. Intermittent volume imaging was performed every 1.5–1.7 s during breath-hold and perfusion values were calculated by maximum-slope technique. Thrombus load (modified Miller score; MMS) and ventricular diameter were determined. Perfusion maps were visually scored and correlated with residual endoluminal filling defects. Results: The mean initial thrombus load was 13.1 ± 4.6 MMS (3–16), and 1.2 ± 2.1 MMS (0–8) at follow up. From the 24 CTPs with diagnostic quality perfusion studies, normal perfusion was observed in 7 (29%), and mildly-severely abnormal in 17 (71%). In 15 patients with no residual thrombus on follow up CTPA, normal perfusion was observed in 6, and abnormal perfusion in 9. Perfusion was abnormal in all patients with residual thrombus on follow up CTPA. Pulmonary perfusion changes were classified as reduced (n = 4), delayed (systemic circulation pattern; n = 5), and absent (no-flow; n = 5). The right ventricle was dilated in 12/25 (48%) at presentation, and normal in all 26 follow up scans. Weak correlation was found between initial ventricular dilatation and perfusion abnormality at follow up (r = 0.15). Conclusions: Most patients had substantial perfusion abnormality at 3–6 months post PE. Abnormal perfusion patterns were frequently observed in patients and in regions with no corresponding evidence of residual thrombus on CTPA. Some defects exhibit delayed, presumed systemic, enhancement (which we have termed ‘stunned’ lung). CT perfusion provides combined anatomical and functional information about PE resolution.

  2. Hydrogen ion changes and contractile behavior in the perfused rat heart

    NARCIS (Netherlands)

    Cingolani, H.E.; Maas, A.H.J.; Zimmerman, A.N.E.; Meijler, F.L.

    1975-01-01

    The effect of acid-base alterations was analyzed using isolated rat hearts perfused at constant coronary perfusion pressure, and stimulated to contract at constant rate. The amount of shortening in the major axis and its derivative were measured to assess myocardial contractility. Both the

  3. Altered carnitine transport in pressure-overload hypertrophied rat hearts

    International Nuclear Information System (INIS)

    O'Rourke, B.; Foster, K.; Reibel, D.K.

    1986-01-01

    The authors have previously observed reduced carnitine levels in hypertrophied hearts of rats subjected to aortic constriction. In an attempt to determine the mechanism for reduced myocardial carnitine content, carnitine transport was examined in isolated perfused hearts. Hearts were excised from sham-operated and aortic-constricted rats 3 weeks following surgery and perfused at 60 mm Hg aortic pressure with buffer containing various concentrations of L- 14 C-carnitine. Carnitine uptake by control and hypertrophied hearts was linear throughout 30 minutes of perfusion with 40 μM carnitine. Total carnitine uptake was significantly reduced by 25% in hypertrophied hearts at each time point examined. The reduction in uptake by hypertrophied hearts was also evident when hearts were perfused with 100 or 200 μM carnitine. When 0.05 mM mersalyl acid was included in the buffer to inhibit the carrier-mediated component of transport, no difference in carnitine uptake was observed indicating that the transport of carnitine by diffusion was unaltered in the hypertrophied myocardium. Carrier-mediated carnitine uptake (total uptake - uptake by diffusion) was significantly reduced by approximately 40% in hypertrophied hearts at all concentrations examined. Thus, the reduction in carnitine content in the pressure-overload hypertrophied rat heart appears to be due to a reduction in carrier-mediated carnitine uptake by the heart

  4. Gammagraphy of cerebral perfusion

    International Nuclear Information System (INIS)

    Vazquez, Silvia

    2003-01-01

    Important aspects of the gammagraphy of cerebral perfusion and the diverse clinical applications in the neurological diseases are comment in this article. We focus in the usefulness of the photon emission cerebral tomography (SPECT) and its capacity to cross the hemato encephalic barrier through the use of radiopharmacons like 99 mTc-H M-PAO and 99mTc-EDC, thus managing to offer functional data on the captantes neurons of the radiopharmacon. The clinical applications of SPECT are studied; cerebrovascular disease, transient ischemic attacks, dementias, Alzheimer disease, as well as other neurological diseases are referred. (The author)

  5. Detectable perfusion changes in MAG3 studies

    International Nuclear Information System (INIS)

    Shuter, B.; Bernar, A.; Roach, P.

    1998-01-01

    Full text: The use of 120 MBq 99m Tc-MAG 3 instead of 600 MBq 99m Tc-DTPA in renal imaging has degraded the images obtained during the perfusion phase. An increase of the minimum detectable change (MDC) in blood flow (BF) would also be expected. In transplant patients, renal BF is an important factor in patient management and the MDC should be small to allow early detection of reduced perfusion. We determined the mean and coefficient of variation (CoV: standard deviation/mean) of three renal perfusion indices as a function of counts in the time-activity curves (TACs). Transplant patients were given a dose of about 300 MBq of 99m Tc-MAG3 and images acquired at 8 fps for 60s. TACs made up from 8, 4, 2 or I images per second allowed calculation of renal perfusion indices as if doses of 300, 150, 75 and 38 MBq had been administered. Perfusion indices based on area under the TACs up to the arterial peak (API), the maximum slopes of the TACs (SPI) and the maximum slope of renal TAC and height of arterial TAC (BPI) were calculated by our routine renal software package. As the administered dose decreased, the CoV rose for all indices, least for BPI and most for API. BPI CoV increased from ∼10% at 300 MBq to 20% at 75 MBq, but API CoV rose from 6% to 46%. Mean BPI was stable over the dose range, but mean API showed a systematic increase of about 50% over the 300 MBq result. We conclude that at 120 MBq the MDC (expressed as 2*CoV) in BF is 30-60%, whereas at 600 MBq it may be as low as 10%, allowing earlier confident detection of a change in BF. The BPI was the preferred perfusion index as its mean value changed little and it had the least CoV at lower activities. The data also imply that relative kidney perfusion in the one individual will be much less accurate with 120 MBq of MAG 3

  6. Isoflurane rescue therapy for bronchospasm reduces intracranial pressure in a patient with traumatic brain injury.

    Science.gov (United States)

    Gradisek, Primoz; Dolenc, Simon

    2016-01-01

    To assess the unusual use of a volatile anaesthetic for treatment of life-threatening bronchospasm in a patient with traumatic brain injury (TBI). Case report. This study presents a previously healthy 30-year-old man with severe TBI and bronchospasm-induced acute hypercapnia. He was treated with inhaled isoflurane in combination with monitoring of intracranial pressure (ICP) and regional cerebral blood flow (rCBF). Three-day-long isoflurane treatment resolved drug-refractory bronchospasm, decreased airway pressure and improved gas exchange, even at a low end-tidal concentration (0.3-0.5 vol%). Although rCBF was increased by 18 ml min(-1) 100 g(-1) during isoflurane treatment, there was a significant decrease in ICP (21 (SD = 3) mmHg, 9 (SD = 5) mmHg, 2 (SD = 3) mmHg; during pre-treatment, treatment and post-treatment, respectively; p < 0.001). Improved autoregulation due to lower partial pressure of carbon dioxide, restoration of carbon dioxide reactivity, isoflurane-induced regional differences in rCBF and improved microcirculation may have been responsible for the prompt and long-lasting normalization of ICP. The patient had no TBI-related disability at 6 months post-injury. Isoflurane at a low dose can be an effective and safe treatment option for drug-refractory bronchospasm in a patient with traumatic intracranial hypertension, provided that multimodality neuromonitoring is used.

  7. An information, education and communication module to reduce dietary salt intake and blood pressure among tea garden workers of Assam

    Directory of Open Access Journals (Sweden)

    Prasanta K. Borah

    2018-03-01

    Full Text Available Objective: High salt diet increases blood pressure. Tea garden workers (TGW of Assam, India have high (60.8% prevalence of hypertension (HTN, which may be due to consumption of extra salt (salt as side dish and salted tea at work place and home. The present study evaluated an information, education and communication (IEC module to reduce salt intake and blood pressure among TGW. Methods: Two tea gardens (usual care and intervention were selected at random covering a total population of 13,458. The IEC module consisting of poster display, leaflets, health rally, documentary show, individual and group discussion was introduced in the intervention garden targeting study participants, health care providers, key stake holders, school children and teachers. IEC intervention was continued for one year. Participants from usual care and intervention were followed at three monthly intervals and BP and other information were compared after one year. Results: A total of 393 study participants (Non intervention: 194; intervention: 199 were included. After one year of follow up, consumption of extra salt was reduced significantly in the intervention participants (66.3 vs. 45.5%, p = 0.000. Intention to treat analysis revealed significant reduction in systolic [−6.4 (−8.6 to −4.2] and diastolic [−6.9 (−8.1 to −5.7] blood pressure after one year. Prevalence of HTN was reduced significantly (52.5 vs. 40.0%, p = 0.02 among them. Conclusions: Our IEC module created awareness about risk of hypertension associated with high salt intake and could reduce dietary salt intake and BP. Keywords: Blood pressure, Dietary salt, Hypertension, Tea garden worker

  8. CT perfusion imaging in the management of posterior reversible encephalopathy

    International Nuclear Information System (INIS)

    Casey, S.O.; McKinney, A.; Teksam, M.; Liu, H.; Truwit, C.L.

    2004-01-01

    A 13-year-old girl with a renal transplant presented with hypertension and seizures. CT and MRI demonstrated typical bilateral parietal, occipital and posterior frontal cortical and subcortical edema, thought to represent posterior reversible encephalopathy syndrome. The cause was presumed to be hypertension. Antihypertensive therapy was started, lowering of the blood pressure in the range of 110-120 mmHg systolic. However, stable xenon (Xe) CT perfusion imaging revealed ischemia within the left parietal occipital region. The antihypertensive was adjusted which increased both the systolic and diastolic blood pressure by 31 mm Hg. The patient was re-imaged with Xe CT and was found to have resolution of the ischemic changes within the left parietal occipital region. In this report, we present a case in which stable Xe CT was used to monitor the degree of cerebral perfusion and guide titration of antihypertensive therapy. Such brain perfusion monitoring may have helped to prevent infarction of our patient. (orig.)

  9. A low-carbohydrate/high-fat diet reduces blood pressure in spontaneously hypertensive rats without deleterious changes in insulin resistance.

    Science.gov (United States)

    Bosse, John D; Lin, Han Yi; Sloan, Crystal; Zhang, Quan-Jiang; Abel, E Dale; Pereira, Troy J; Dolinsky, Vernon W; Symons, J David; Jalili, Thunder

    2013-06-15

    Previous studies reported that diets high in simple carbohydrates could increase blood pressure in rodents. We hypothesized that the converse, a low-carbohydrate/high-fat diet, might reduce blood pressure. Six-week-old spontaneously hypertensive rats (SHR; n = 54) and Wistar-Kyoto rats (WKY; n = 53, normotensive control) were fed either a control diet (C; 10% fat, 70% carbohydrate, 20% protein) or a low-carbohydrate/high-fat diet (HF; 20% carbohydrate, 60% fat, 20% protein). After 10 wk, SHR-HF had lower (P vs. 159 ± 3 mmHg) but a similar degree of cardiac hypertrophy (33.4 ± 0.4 vs. 33.1 ± 0.4 heart weight/tibia length, mg/mm). Mesenteric arteries and the entire aorta were used to assess vascular function and endothelial nitric oxide synthase (eNOS) signaling, respectively. Endothelium-dependent (acetylcholine) relaxation of mesenteric arteries was improved (P vs. SHR-C, whereas contraction (potassium chloride, phenylephrine) was reduced (P vs. SHR-C. Plasma glucose, insulin, and homoeostatic model of insulin assessment were lower (P vs. SHR-C, whereas peripheral insulin sensitivity (insulin tolerance test) was similar. After a 10-h fast, insulin stimulation (2 U/kg ip) increased (P vs. SHR-HF. In conclusion, a low-carbohydrate/high-fat diet reduced blood pressure and improved arterial function in SHR without producing signs of insulin resistance or altering insulin-mediated signaling in the heart, skeletal muscle, or vasculature.

  10. Advanced Cookware and Techniques for Food Preparation at Reduced Pressure and Gravity, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Makel Engineering and Cornell University propose to develop a galley architecture taking into account the design constraints of the space habitat, such as reduced...

  11. Reduced Pressure-Chemical Vapour Deposition of Si/SiGe heterostructures for nanoelectronics

    International Nuclear Information System (INIS)

    Hartmann, J.M.; Andrieu, F.; Lafond, D.; Ernst, T.; Bogumilowicz, Y.; Delaye, V.; Weber, O.; Rouchon, D.; Papon, A.M.; Cherkashin, N.

    2008-01-01

    We have first of all quantified the impact of pressure on Si and SiGe growth kinetics. Definite growth rate and Ge concentration increases with the pressure have been evidenced at low temperatures (650-750 deg. C). By contrast, the high temperature (950-1050 deg. C) Si growth rate either increases or decreases with pressure (gaseous precursor depending). We have then described the selective epitaxial growth process we use to form Si or Si 0.7 Ge 0.3 :B raised sources and drains on ultra-thin patterned Silicon-On-Insulator (SOI) substrates. We have afterwards presented the specifics of SiGe virtual substrates and of the tensile-strained Si layers grown on top (used as templates for the elaboration of tensily strained-SOI wafers). The tensile strain, which can be tailored from 1.3 up to 3 GPa, leads to an electron mobility gain by a factor of 2 in n-Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) built on top. High Ge content SiGe virtual substrates can also be used for the elaboration of compressively strained Ge channels, with impressive hole mobility gains (x9) compared to bulk Si. After that, we have described the main structural features of thick Ge layers grown directly on Si (that can be used as donor wafers for the elaboration of GeOI wafers or as the active medium of near infrared photo-detectors). Finally, we have shown how Si/SiGe multilayers can be used for the formation of high performance 3D devices such as multi-bridge channel or nano-beam gate-all-around FETs, the SiGe sacrificial layers being removed thanks to plasma dry etching, wet etching or in situ gaseous HCl etching

  12. A Review of Liver Perfusion Method in Toxicology Studies

    Directory of Open Access Journals (Sweden)

    M karami

    2014-06-01

    Full Text Available Introduction: The isolated perfused rat liver is an accepted method in toxicology studies. The isolated perfused rat liver (IPRL is a useful experimental system for evaluating hepatic function without the influence of other organ systems, undefined plasma constituents, and neural-hormonal effects. Methods: The untreated male rats (180-220gr body weight were anesthetised with ether and then surgery with proper method. The abdomen was opened through a midline and one transversal incision and the bile duct was cannulated. Heparin sodium solution (0.5 ml; 500 U/ml in 0.9% NaCl was injected via the abdominal vena cava to prevent blood clotting. The liver inferior venacava was cannulated with PE-10 tubing and secured. The portal vein was immediately cannulated with an 23gr catheter which was secured and then liver was perfused in situ by Krebs- Henseleit buffer (pH 7.4; saturated with 95% O2 and 5% CO2; 37°C at a flow rate of 20 ml/min for 3hr. Temperature, perfusion pressure, flow rate and perfusion fluid pH were closely monitored during the perfusion. Results: Transferase enzymes (ALT, AST alterations can be widely used as a measure of biochemical alterations in order to assess liver damage due to use of drugs such as isoniazid (INH and animal and plant toxins. Accumulated material in gallbladder are valuable samples to assess the level of Glutathione (GSH. Sections of perfused liver tissue can also be effectively analyzed for pathological aspects such as necrosis, fibrosis, cellularity. Conclusion: The isolated perfused rat liver (IPRL is a useful and Sutible experimental system for evaluating hepatic function. In this system, the effects of adjacent organs, on the liver is minimized

  13. Renal perfusion in chronic liver diseases: Evaluation by radiotechnetium renography

    International Nuclear Information System (INIS)

    Fanfani, G.; Fratello, A.; Mele, M.; Conte, E.; D'Addabbo, A.; Greco, L.

    1985-01-01

    Twenty-four patients with chronic liver diseases and seven normal controls were studied using renal and hepatic radiotechnetium angiography. The time-activity histograms generated were employed to calculate both the renal perfusion index (RPI) and the hepatic perfusion index (HPI). Renal perfusion proved to be reduced not only in cirrhotic patients but also in patients with aggressive chronic hepatitis, as well as in those with persistent chronic hepatitis. The HPI, which is to be considered as being strictly dependent on portal flow, only fell significantly in the group of cirrhotic patients. In all patient groups, the correlation coefficient between the HPI and RPI (mean of the two kidneys) was low (r=0.275) and not significant (P>0.05). After Warren's splenorenal derivation, renal perfusion did not improve but worsened, particularly in the left kidney where derivation anastomosis probably caused a venous overload. (orig.)

  14. The value of reducing hospital-acquired pressure ulcer prevalence: an illustrative analysis.

    Science.gov (United States)

    Spetz, Joanne; Brown, Diane S; Aydin, Carolyn; Donaldson, Nancy

    2013-04-01

    The aim of this study was to assess the cost savings associated with implementing nursing approaches to prevent hospital-acquired pressure ulcers (HAPU). Hospitals face substantial costs associated with the treatment of HAPUs. Interventions have been demonstrated as effective for HAPU prevention and management, but it is widely perceived that preventative measures are expensive and, thus, may not be a good use of resources. A return-on-investment (ROI) framework from the Agency for Healthcare Research and Quality (AHRQ) Quality Indicators Toolkit was used for this study. The researchers identified achievable improvements in HAPU rates from data from the Collaborative Alliance for Nursing Outcomes and measured costs and savings associated with HAPU reduction from published literature. The analysis produced a baseline ROI ratio of 1.61 and net savings of $127.51 per patient. Hospital-acquired pressure ulcer surveillance and prevention can be cost saving for hospitals and should be considered by nurse executives as a strategy to support quality outcomes.

  15. Oxidation of SiC/BN/SiC Composites in Reduced Oxygen Partial Pressures

    Science.gov (United States)

    Opila, Elizabeth J.; Boyd, Meredith

    2010-01-01

    SiC fiber-reinforced SiC composites with a BN interphase are proposed for use as leading edge structures of hypersonic vehicles. The durability of these materials under hypersonic flight conditions is therefore of interest. Thermogravimetric analysis was used to characterize the oxidation kinetics of both the constituent fibers and composite coupons at four temperatures: 816, 1149, 1343, and 1538 C (1500, 2100, 2450, and 2800 F) and in oxygen partial pressures between 5% and 0.1% (balance argon) at 1 atm total pressure. One edge of the coupons was ground off so the effects of oxygen ingress into the composite could be monitored by post-test SEM and EDS. Additional characterization of the oxidation products was conducted by XPS and TOF-SIMS. Under most conditions, the BN oxidized rapidly, leading to the formation of borosilicate glass. Rapid initial oxidation followed by volatilization of boria lead to protective oxide formation and further oxidation was slow. At 1538C in 5% oxygen, both the fibers and coupons exhibited borosilicate glass formation and bubbling. At 1538C in 0.1% oxygen, active oxidation of both the fibers and the composites was observed leading to rapid SiC degradation. BN oxidation at 1538C in 0.1% oxygen was not significant.

  16. Lower blasthole pressures: a means of reducing costs when blasting rocks of low to moderate strength

    Energy Technology Data Exchange (ETDEWEB)

    Hagan, T.N.; Gibson, I.M.

    1988-03-01

    From a purely mechanical viewpoint, each explosive charge should produce a peak blasthole pressure (P/sub b/) that just fails to crush (i.e. pulverise or plastically deform) the rock which surrounds it. Where P/sub b/ exceeds a critical value, some explosion energy is wasted in crushing an annular section of rock immediately around each charge. As a rock's dynamic compressive breaking strain decreases, so should P/sub b/ (Hagan, 1977b). This paper reviews information on, and anticipates the blasting performance of, bulk charges having effective densities which are as low as about 40% of that for ammonium nitrate fuel oil (ANFO). It also outlines the potential advantages of extending the reaction periods of charges, even to the extent that explosive reactions continue after the blasthole wall and stemming have started to move. The paper then proceeds to define situations in which the use of such lower-pressure charges is likely to result in greatest reductions in mining costs. Some methods of applying bulk charges having effective densities in the 0.3-0.8 g cm/sup -3/ range and/or lower reaction rates are suggested. 15 refs., 3 figs.

  17. Development of a test method for distillation of diesel-biodiesel-alcohols mixtures at reduced pressure

    Science.gov (United States)

    Niculescu, R.; Iosub, I.; Clenci, A.; Zaharia, C.; Iorga-Simăn, V.

    2017-10-01

    Increased environmental awareness and depletion of fossil petroleum resources are driving the automotive industry to seek out and use alternative fuels. For instance, the biofuel is a major renewable energy source to supplement declining fossil fuel resources. The addition of alcohols like methanol and ethanol is practical in biodiesel blends due to its miscibility with the pure biodiesel. Alcohols also improve physico-chemical properties of biodiesel blends, which lead to improved combustion efficiency. Proper volatility of fuels is critical to the operation of internal combustion engines with respect to both performance and emissions. Volatility may be characterised by various measurements, the most common of which are vapour pressure, distillation and the vapour/liquid ratio. The presence of ethanol or other oxygenates may affect these properties and, as a result, performance and emissions, as well. However, in the case of diesel-biodiesel-alcohols mixtures, the variance of component volatility makes difficult the analysis of the overall volatility. Thus, the paper presents an experimental method of distilling diesel-biodiesel-alcohols mixtures by adjusting the boiler pressure of an i-Fischer Dist equipment.

  18. Brain perfusion CT in acute stroke: current status

    Energy Technology Data Exchange (ETDEWEB)

    Koenig, Matthias E-mail: matthias.koenig@ruhr-uni-bochum.de

    2003-03-01

    Dynamic perfusion CT has become a widely accepted imaging modality for the diagnostic workup of acute stroke patients. Although compared with standard spiral CT the use of multislice CT has broadened the range from which perfusion data may be derived in a single scan run. The advent of multidetector row technology has not really overcome the limited 3D capability of this technique. Multidetector CT angiography (CTA) of the cerebral arteries may in part compensate for this by providing additional information about the cerebrovascular status. This article describes the basics of cerebral contrast bolus scanning with a special focus on optimization of contrast/noise in order to ensure high quality perfusion maps. Dedicated scan protocols including low tube voltage (80 kV) as well as the use of highly concentrated contrast media are amongst the requirements to achieve optimum contrast signal from the short bolus passage through the brain. Advanced pre and postprocessing algorithms may help reduce the noise level, which may become critical in unconscious stroke victims. Two theoretical concepts have been described for the calculation of tissue perfusion from contrast bolus studies, both of which can be equally employed for brain perfusion imaging. For each perfusion model there are some profound limitations regarding the validity of perfusion values derived from ischemic brain areas. This makes the use of absolute quantitative cerebral blood flow (CBF) values for the discrimination of the infarct core from periinfarct ischemia questionable. Multiparameter imaging using maps of CBF, cerebral blood volume (CBV), and a time parameter of the local bolus transit enables analyzing of the cerebral perfusion status in detail. Perfusion CT exceeds plain CT in depicting cerebral hypoperfusion at its earliest stage yielding a sensitivity of about 90% for the detection of embolic and hemodynamic lesions within cerebral hemispheres. Qualitative assessment of brain perfusion can be

  19. Enhanced magnetic resonance pulmonary perfusion imaging in diagnosing pulmonary embolism: preliminary investigation

    International Nuclear Information System (INIS)

    Huang Xiaoyong; Du Jing; Zhang Zhaoqi; Guo Xi; Yan Zixu; Jiang Hong; Wang Wei

    2005-01-01

    Objective: This study was designed to investigate the sensitivity and specificity of magnetic resonance pulmonary perfusion imaging (MRPP) in diagnosing pulmonary embolism (PE) compared with enhanced magnetic resonance pulmonary angiography (MRPA) and pulmonary radionuclide perfusion imaging. Methods: Fourteen patients were definitely diagnosed as PE, whose ages were from 19 to 71 years old and mean 45.5 ± 19.8 years old. All patients under went MRPA and MRPP and 3 patients were examined again after thrombolytic treatment. Five patients underwent pulmonary radionuclide perfusion imaging. Setting ROI in top, middle, bottom of lung area and abnormal area respectively, we detected signal intensity and time-signal curve to obtain the transformation rate of signal (TROS) during perfusion peak value. Results: In 14 pulmonary embolism patients, MRPA found 62 branches of pulmonary artery obstruction. Fifty-five abnormal pulmonary perfusion zones were found by MRPP, and the above results were very alike. The coincidence was 88.71%. In 14 cases, MRPP could show 25 subsegments lesion below segments. In 5 patients who had both results Of MRPP and ECT at the same time. MRPP shows 33 perfusion defect zones and 37 segments were found by ECT, the sensitivity was 89.19%. After thrombolytic treatment, both the status of the affected pulmonary artery improved markedly and perfusion defect zones reduced obviously in 3 cases by MRPP and MRPA. TROS in normal perfusion zones perfusion defect zones and low perfusion zones had significant difference (t=22.882, P<0.01). Conclusion: Contrast enhanced MR pulmonary perfusion can show both perfusion defect zones and low perfusion zones in pulmonary embolism. Time-signal curve can show the period of maximum no perfusion zones in pulmonary artery embolism zones. And the amplitude of fluctuation is small with miminum TROS. MRPP has significant values especially in showing pulmonary artery embolism in segments and subsegments. Using both MRPP and

  20. The benefits of prone SPECT myocardial perfusion imaging in reducing both artifact defects and patient radiation exposure; Beneficio da aquisicao de imagem na posicao Prona em perfusao miocardica com SPECT para reducao de artefatos e exposicao do paciente a radiacao

    Energy Technology Data Exchange (ETDEWEB)

    Stathaki, Maria; Koukouraki, Sophia; Papadaki, Emmanouela; Tsaroucha, Angeliki; Karkavitsas, Nikolaos, E-mail: mariast_cha@yahoo.gr [Department of Nuclear Medicine, University Hospital of Heraklion, Crete (Greece)

    2015-10-15

    Background: Prone imaging has been demonstrated to minimize diaphragmatic and breast tissue attenuation. Objectives: To determine the role of prone imaging on the reduction of unnecessary rest perfusion studies and coronary angiographies performed, thus decreasing investigation time and radiation exposure. Methods: We examined 139 patients, 120 with an inferior wall and 19 with an anterior wall perfusion defect that might represented attenuation artifact. Post-stress images were acquired in both the supine and prone position. Coronary angiography was used as the 'gold standard' for evaluating coronary artery patency. The study was terminated and rest imaging was obviated in the presence of complete improvement of the defect in the prone position. Quantitative interpretation was performed. Results were compared with clinical data and coronary angiographic findings. Results: Prone acquisition correctly revealed defect improvement in 89 patients (89/120) with inferior wall and 12 patients (12/19) with anterior wall attenuation artifact. Quantitative analysis demonstrated statistically significant difference in the mean summed stress scores (SSS) of supine and mean SSS of prone studies in patients with disappearing inferior wall defect in the prone position and patent right coronary artery (true negative results). The mean difference between SSS in supine and in prone position was higher with disappearing than with remaining defects. Conclusion: Technetium-99m (Tc-99m) tetrofosmin myocardial perfusion imaging with the patient in the prone position overcomes soft tissue attenuation; moreover it provides an inexpensive, accurate approach to limit the number of unnecessary rest perfusion studies and coronary angiographies performed. (author)

  1. Method of purifying metallurgical grade silicon employing reduced pressure atmospheric control

    Science.gov (United States)

    Ingle, W. M.; Thompson, S. W.; Chaney, R. E. (Inventor)

    1979-01-01

    A method in which a quartz tube is charged with chunks of metallurgical grade silicon and/or a mixture of such chunks and high purity quartz sand, and impurities from a class including aluminum, boron, as well as certain transition metals including nickel, iron, and manganese is described. The tube is then evacuated and heated to a temperature within a range of 800 C to 1400 C. A stream of gas comprising a reactant, such as silicon tetrafluoride, is continuously delivered at low pressures through the charge for causing a metathetical reaction of impurities of the silicon and the reactant to occur for forming a volatile halide and leaving a residue of silicon of an improved purity. The reactant which included carbon monoxide gas and impurities such as iron and nickel react to form volatile carbonyls.

  2. Leptin receptor blockade reduces intrahepatic vascular resistance and portal pressure in an experimental model of rat liver cirrhosis.

    Science.gov (United States)

    Delgado, María Gabriela; Gracia-Sancho, Jordi; Marrone, Giusi; Rodríguez-Vilarrupla, Aina; Deulofeu, Ramon; Abraldes, Juan G; Bosch, Jaume; García-Pagán, Juan Carlos

    2013-10-01

    Increased hepatic vascular resistance mainly due to elevated vascular tone and to fibrosis is the primary factor in the development of portal hypertension in cirrhosis. Leptin, a hormone associated with reduction in nitric oxide bioavailability, vascular dysfunction, and liver fibrosis, is increased in patients with cirrhosis. We aimed at evaluating whether leptin influences the increased hepatic resistance in portal hypertension. CCl4-cirrhotic rats received the leptin receptor-blocker ObR antibody, or its vehicle, every other day for 1 wk. Hepatic and systemic hemodynamics were measured in both groups. Hepatic nitric oxide production and bioavailability, together with oxidative stress, nitrotyrosinated proteins, and liver fibrosis, were evaluated. In cirrhotic rats, leptin-receptor blockade significantly reduced portal pressure without modifying portal blood flow, suggesting a reduction in the intrahepatic resistance. Portal pressure reduction was associated with increased nitric oxide bioavailability and with decreased O2(-) levels and nitrotyrosinated proteins. No changes in systemic hemodynamics and liver fibrosis were observed. In conclusion, the present study shows that blockade of the leptin signaling pathway in cirrhosis significantly reduces portal pressure. This effect is probably due to a nitric oxide-mediated reduction in the hepatic vascular tone.

  3. Instability of supercritical porosity in highly doped ceria under reduced oxygen partial pressure

    DEFF Research Database (Denmark)

    Teocoli, Francesca; Ni, De Wei; Esposito, Vincenzo

    2015-01-01

    The thermomechanical behavior and microstructural evolution of low relative density (∼0.40) gadolinium-doped ceria are characterized under oxidative and reducing conditions at high temperatures. The electronic defects generated in the structure by Ce4+ to Ce3+ reduction play an important role on ...

  4. Strategies to reduce the environmental impact of an aluminium pressure die casting plant: A scenario analysis

    NARCIS (Netherlands)

    Neto, B.; Kroeze, C.; Hordijk, L.; Costa, C.; Pulles, M.P.J.

    2009-01-01

    This study explores a model (MIKADO) to analyse scenarios for the reduction of the environmental impact of an aluminium die casting plant. Our model calculates the potential to reduce emissions, and the costs associated with implementation of reduction options. In an earlier paper [Neto, B., Kroeze,

  5. Pressure overload-induced mild cardiac hypertrophy reduces leftventricular transmural differences in mitochondrial respiratory chainactivity and increases oxidative stress

    Directory of Open Access Journals (Sweden)

    Michel eKINDO

    2012-08-01

    Full Text Available Objective: Increased mechanical stress and contractility characterizes normal left ventricular subendocardium (Endo but whether Endo mitochondrial respiratory chain complex activities is reduced as compared to subepicardium (Epi and whether pressure overload-induced left ventricular hypertrophy (LVH might modulate transmural gradients through increased reactive oxygen species (ROS production is unknown. Methods: LVH was induced by 6 weeks abdominal aortic banding and cardiac structure and function were determined with echocardiography and catheterization in sham-operated and LVH rats (n=10 for each group. Mitochondrial respiration rates, coupling, content and ROS production were measured in LV Endo and Epi, using saponin-permeabilised fibres, Amplex Red fluorescence and citrate synthase activity.Results: In sham, a transmural respiratory gradient was observed with decreases in endo maximal oxidative capacity (-36.7%, P<0.01 and complex IV activity (-57.4%, P<0.05. Mitochondrial hydrogen peroxide (H2O2 production was similar in both LV layers.Aortic banding induced mild LVH (+31.7% LV mass, associated with normal LV fractional shortening and end diastolic pressure. LVH reduced maximal oxidative capacity (-23.6 and -33.3%, increased mitochondrial H2O2 production (+86.9 and +73.1%, free radical leak (+27.2% and +36.3% and citrate synthase activity (+27.2% and +36.3% in Endo and Epi, respectively.Transmural mitochondrial respiratory chain complex IV activity was reduced in LVH (-57.4 vs –12.2%; P=0.02. Conclusions: Endo mitochondrial respiratory chain complexes activities are reduced compared to LV Epi. Mild LVH impairs mitochondrial oxidative capacity, increases oxidative stress and reduces transmural complex IV activity. Further studies will be helpful to determine whether reduced LV transmural gradient in mitochondrial respiration might be a new marker of a transition from uncomplicated toward complicated LVH.

  6. Brain perfusion: computed tomography applications

    International Nuclear Information System (INIS)

    Miles, K.A.

    2004-01-01

    Within recent years, the broad introduction of fast multi-detector computed tomography (CT) systems and the availability of commercial software for perfusion analysis have made cerebral perfusion imaging with CT a practical technique for the clinical environment. The technique is widely available at low cost, accurate and easy to perform. Perfusion CT is particularly applicable to those clinical circumstances where patients already undergo CT for other reasons, including stroke, head injury, subarachnoid haemorrhage and radiotherapy planning. Future technical developments in multi-slice CT systems may diminish the current limitations of limited spatial coverage and radiation burden. CT perfusion imaging on combined PET-CT systems offers new opportunities to improve the evaluation of patients with cerebral ischaemia or tumours by demonstrating the relationship between cerebral blood flow and metabolism. Yet CT is often not perceived as a technique for imaging cerebral perfusion. This article reviews the use of CT for imaging cerebral perfusion, highlighting its advantages and disadvantages and draws comparisons between perfusion CT and magnetic resonance imaging. (orig.)

  7. High-Pressure-High-Temperature Processing Reduces Maillard Reaction and Viscosity in Whey Protein-Sugar Solutions.

    Science.gov (United States)

    Avila Ruiz, Geraldine; Xi, Bingyan; Minor, Marcel; Sala, Guido; van Boekel, Martinus; Fogliano, Vincenzo; Stieger, Markus

    2016-09-28

    The aim of the study was to determine the influence of pressure in high-pressure-high-temperature (HPHT) processing on Maillard reactions and protein aggregation of whey protein-sugar solutions. Solutions of whey protein isolate containing either glucose or trehalose at pH 6, 7, and 9 were treated by HPHT processing or conventional high-temperature (HT) treatments. Browning was reduced, and early and advanced Maillard reactions were retarded under HPHT processing at all pH values compared to HT treatment. HPHT induced a larger pH drop than HT treatments, especially at pH 9, which was not associated with Maillard reactions. After HPHT processing at pH 7, protein aggregation and viscosity of whey protein isolate-glucose/trehalose solutions remained unchanged. It was concluded that HPHT processing can potentially improve the quality of protein-sugar-containing foods, for which browning and high viscosities are undesired, such as high-protein beverages.

  8. Statin therapy reduces the likelihood of suboptimal blood pressure control among Ugandan adult diabetic patients

    Directory of Open Access Journals (Sweden)

    Lumu W

    2017-02-01

    Full Text Available William Lumu,1 Leaticia Kampiire,2 George Patrick Akabwai,3 Daniel Ssekikubo Kiggundu,4 Davis Kibirige5 1Department of Medicine and Diabetes/Endocrine Unit, Mengo Hospital, 2Infectious Disease Research Collaboration, 3Baylor College of Medicine Children’s Foundation, 4Nephrology Unit, Mulago National Referral and Teaching Hospital, 5Department of Medicine, Uganda Martyrs Hospital Lubaga, Kampala, Uganda Background: Hypertension is one of the recognized risk factors of cardiovascular diseases in adult diabetic patients. High prevalence of suboptimal blood pressure (BP control has been well documented in the majority of studies assessing BP control in diabetic patients in sub-Saharan Africa. In Uganda, there is a dearth of similar studies. This study evaluated the prevalence and correlates of suboptimal BP control in an adult diabetic population in Uganda.Patients and methods: This was a cross-sectional study that enrolled 425 eligible ambulatory adult diabetic patients attending three urban diabetic outpatient clinics over 11 months. Data about their sociodemographic characteristics and clinical history were collected using pre-tested questionnaires. Suboptimal BP control was defined according to the 2015 American Diabetes Association standards of diabetes care guideline as BP levels ≥140/90 mmHg.Results: The mean age of the study participants was 52.2±14.4 years, with the majority being females (283, 66.9%. Suboptimal BP control was documented in 192 (45.3% study participants and was independently associated with the study site (private hospitals; odds ratio 2.01, 95% confidence interval 1.18–3.43, P=0.01 and use of statin therapy (odds ratio 0.5, 95% confidence interval 0.26–0.96, P=0.037.Conclusion: Suboptimal BP control was highly prevalent in this study population. Strategies to improve optimal BP control, especially in the private hospitals, and the use of statin therapy should be encouraged in adult diabetic patients

  9. A Clinical Nurse Specialist-Led Interprofessional Quality Improvement Project to Reduce Hospital-Acquired Pressure Ulcers.

    Science.gov (United States)

    Fabbruzzo-Cota, Christina; Frecea, Monica; Kozell, Kathryn; Pere, Katalin; Thompson, Tamara; Tjan Thomas, Julie; Wong, Angela

    2016-01-01

    The purpose of this clinical nurse specialist-led interprofessional quality improvement project was to reduce hospital-acquired pressure ulcers (HAPUs) using evidence-based practice. Hospital-acquired pressure ulcers (PUs) have been linked to morbidity, poor quality of life, and increasing costs. Pressure ulcer prevention and management remain a challenge for interprofessional teams in acute care settings. Hospital-acquired PU rate is a critical nursing quality indicator for healthcare organizations and ties directly with Mount Sinai Hospital's (MSH's) mission and vision, which mandates providing the highest quality care to patients and families. This quality improvement project, guided by the Donabedian model, was based on the Registered Nurses' Association of Ontario Best Practice Guideline Risk Assessment & Prevention of Pressure Ulcers. A working group was established to promote evidence-based practice for PU prevention. Initiatives such as documentation standardization, development of staff education and patient and family educational resources, initiation of a hospital-wide inventory for support surfaces, and procurement of equipment were implemented to improve PU prevention and management across the organization. An 80% decrease in HAPUs has been achieved since the implementation of best practices by the Best Practice Guideline Pressure Ulcer working group. The implementation of PU prevention strategies led to a reduction in HAPU rates. The working group will continue to work on building interprofessional awareness and collaboration in order to prevent HAPUs and promote an organizational culture that supports staff development, teamwork and communication. This quality improvement project is a successful example of an interprofessional clinical nurse specialist-led initiative that impacts patient/family and organization outcomes through the identification and implementation of evidence-based nursing practice.

  10. Cocoa reduces blood pressure and insulin resistance and improves endothelium-dependent vasodilation in hypertensives.

    Science.gov (United States)

    Grassi, Davide; Necozione, Stefano; Lippi, Cristina; Croce, Giuseppe; Valeri, Letizia; Pasqualetti, Paolo; Desideri, Giovambattista; Blumberg, Jeffrey B; Ferri, Claudio

    2005-08-01

    Consumption of flavanol-rich dark chocolate (DC) has been shown to decrease blood pressure (BP) and insulin resistance in healthy subjects, suggesting similar benefits in patients with essential hypertension (EH). Therefore, we tested the effect of DC on 24-hour ambulatory BP, flow-mediated dilation (FMD), and oral glucose tolerance tests (OGTTs) in patients with EH. After a 7-day chocolate-free run-in phase, 20 never-treated, grade I patients with EH (10 males; 43.7+/-7.8 years) were randomized to receive either 100 g per day DC (containing 88 mg flavanols) or 90 g per day flavanol-free white chocolate (WC) in an isocaloric manner for 15 days. After a second 7-day chocolate-free period, patients were crossed over to the other treatment. Noninvasive 24-hour ambulatory BP, FMD, OGTT, serum cholesterol, and markers of vascular inflammation were evaluated at the end of each treatment. The homeostasis model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), and insulin sensitivity index (ISI) were calculated from OGTT values. Ambulatory BP decreased after DC (24-hour systolic BP -11.9+/-7.7 mm Hg, Pbenefit if included as part of a healthy diet for patients with EH.

  11. Performance of core modifications to reduce the reactor pressure vessel fluence

    International Nuclear Information System (INIS)

    Kiehlmann, H.D.; Lisdat, R.; Sommer, D.

    1997-01-01

    It's often discussed that nuclear power plants (NPP) are designed for an operation of 40 years equivalent to 32 full power years (FPY) assuming a load factor of 0.8. Such fixed plant life times are subjects of US operating licenses but not, as in most other countries, in the Federal Republic of Germany. Here the operating licenses are issued for an indefinite period. However, the German utilities are continuously upgrading their plants to attain a safety level that meets all current requirements. These upgrading measures also include the replacement of bigger components like e.g. the steam generator. The reactor pressure vessel (RPV), however, has a special status. Unlike most other components of a NPP which most likely will be exchanged during its service life a replacement or annealing treatment of the RPV certainly require more efforts to be economically justified. Thus the embrittlement of the RPV has an essential impact on the life time of a NPP. The end-of-life (EOL) RPV material toughness in essential depends on the steel quality and the accumulated neutron fluence. For a given NPP the reduction of the neutron flux at the inner surface of the RPV is the only way to limit its embrittlement. The resulting modifications for the core loadings in combination with the insertion of additional core components like steel elements are described and the impact on core performance and RPV fluence considered. (UK)

  12. Placental perfusion - a human alternative

    DEFF Research Database (Denmark)

    Mose, Tina; Knudsen, Lisbeth E

    2006-01-01

    Foetal exposures to environmental and medicinal products have impact on the growth of the foetus (e.g. cigarette smoke) and development of organs (e.g. methylmercury and Thalidomide). Perfusion studies of the human term placenta enable investigation of placental transport of chemical substances...... between the mother and foetus. Dual perfusion of a single cotyledon in the human placenta can contribute to a better understanding of the placental barrier, transport rate and mechanisms of different substances and placental metabolism. The perfusion system has recently been established in Copenhagen...

  13. Microdialysis to optimize cord perfusion and drug delivery in spinal cord injury.

    OpenAIRE

    Phang, I; Zoumprouli, A; Papadopoulos, MC; Saadoun, S

    2016-01-01

    OBJECTIVE: There is lack of monitoring from the injury site to guide management of patients with acute traumatic spinal cord injury. Here we describe a bedside microdialysis monitoring technique for optimizing spinal cord perfusion and drug delivery at the injury site. METHODS: 14 patients were recruited within 72 hours of severe spinal cord injury. We inserted intradurally at the injury site a pressure probe, to monitor continuously spinal cord perfusion pressure, and a microdialysis cathete...

  14. Nuclear magnetic resonance of perfused tissue

    International Nuclear Information System (INIS)

    Harpen, M.D.; Allison, R.C.

    1986-01-01

    The effect of perfusion on the NMR signal observed in NMR imaging is studied in a phantom and in two isolated perfused canine lungs. It is observed that perfusion in tissue has little effect on longitudinal relaxation times. Transverse relaxation rates are observed to correlate linearly with rates of perfusion, in accordance with a model presented. (author)

  15. Low LET radiolysis escape yields for reducing radicals and H2 in pressurized high temperature water

    Science.gov (United States)

    Sterniczuk, Marcin; Yakabuskie, Pamela A.; Wren, J. Clara; Jacob, Jasmine A.; Bartels, David M.

    2016-04-01

    Low Linear Energy Transfer (LET) radiolysis escape yields (G values) are reported for the sum (G(radH)+G(e-)aq) and for G(H2) in subcritical water up to 350 °C. The scavenger system 1-10 mM acetate/0.001 M hydroxide/0.00048 M N2O was used with simultaneous mass spectroscopic detection of H2 and N2 product. Temperature-dependent measurements were carried out with 2.5 MeV electrons from a van de Graaff accelerator, while room temperature calibration measurements were done with a 60Co gamma source. The concentrations and dose range were carefully chosen so that initial spur chemistry is not perturbed and the N2 product yield corresponds to those reducing radicals that escape recombination in pure water. In comparison with a recent review recommendation of Elliot and Bartels (AECL report 153-127160-450-001, 2009), the measured reducing radical yield is seven percent smaller at room temperature but in fairly good agreement above 150 °C. The H2 escape yield is in good agreement throughout the temperature range with several previous studies that used much larger radical scavenging rates. Previous analysis of earlier high temperature measurements of Gesc(radOH) is shown to be flawed, although the actual G values may be nearly correct. The methodology used in the present report greatly reduces the range of possible error and puts the high temperature escape yields for low-LET radiation on a much firmer quantitative foundation than was previously available.

  16. Digoxin derivatives with selectivity for the α2β3 isoform of Na,K-ATPase potently reduce intraocular pressure.

    Science.gov (United States)

    Katz, Adriana; Tal, Daniel M; Heller, Dan; Habeck, Michael; Ben Zeev, Efrat; Rabah, Bilal; Bar Kana, Yaniv; Marcovich, Arie L; Karlish, Steven J D

    2015-11-03

    The ciliary epithelium in the eye consists of pigmented epithelial cells that express the α1β1 isoform of Na,K-ATPase and nonpigmented epithelial cells that express mainly the α2β3 isoform. In principle, a Na,K-ATPase inhibitor with selectivity for α2β3 that penetrates the cornea could effectively reduce intraocular pressure, with minimal systemic or local toxicity. We have recently synthesized perhydro-1,4-oxazepine derivatives of digoxin by NaIO4 oxidation of the third digitoxose and reductive amination with various R-NH2 substituents and identified derivatives with significant selectivity for human α2β1 over α1β1 (up to 7.5-fold). When applied topically, the most α2-selective derivatives effectively prevented or reversed pharmacologically raised intraocular pressure in rabbits. A recent structure of Na,K-ATPase, with bound digoxin, shows the third digitoxose approaching one residue in the β1 subunit, Gln84, suggesting a role for β in digoxin binding. Gln84 in β1 is replaced by Val88 in β3. Assuming that alkyl substituents might interact with β3Val88, we synthesized perhydro-1,4-oxazepine derivatives of digoxin with diverse alkyl substituents. The methylcyclopropyl and cyclobutyl derivatives are strongly selective for α2β3 over α1β1 (22-33-fold respectively), as determined either with purified human isoform proteins or intact bovine nonpigmented epithelium cells. When applied topically on rabbit eyes, these derivatives potently reduce both pharmacologically raised and basal intraocular pressure. The cyclobutyl derivative is more efficient than Latanoprost, the most widely used glaucoma drug. Thus, the conclusion is that α2β3-selective digoxin derivatives effectively penetrate the cornea and inhibit the Na,K-ATPase, hence reducing aqueous humor production. The new digoxin derivatives may have potential for glaucoma drug therapy.

  17. Quantitative lung perfusion evaluation using Fourier decomposition perfusion MRI.

    Science.gov (United States)

    Kjørstad, Åsmund; Corteville, Dominique M R; Fischer, Andre; Henzler, Thomas; Schmid-Bindert, Gerald; Zöllner, Frank G; Schad, Lothar R

    2014-08-01

    To quantitatively evaluate lung perfusion using Fourier decomposition perfusion MRI. The Fourier decomposition (FD) method is a noninvasive method for assessing ventilation- and perfusion-related information in the lungs, where the perfusion maps in particular have shown promise for clinical use. However, the perfusion maps are nonquantitative and dimensionless, making follow-ups and direct comparisons between patients difficult. We present an approach to obtain physically meaningful and quantifiable perfusion maps using the FD method. The standard FD perfusion images are quantified by comparing the partially blood-filled pixels in the lung parenchyma with the fully blood-filled pixels in the aorta. The percentage of blood in a pixel is then combined with the temporal information, yielding quantitative blood flow values. The values of 10 healthy volunteers are compared with SEEPAGE measurements which have shown high consistency with dynamic contrast enhanced-MRI. All pulmonary blood flow (PBF) values are within the expected range. The two methods are in good agreement (mean difference = 0.2 mL/min/100 mL, mean absolute difference = 11 mL/min/100 mL, mean PBF-FD = 150 mL/min/100 mL, mean PBF-SEEPAGE = 151 mL/min/100 mL). The Bland-Altman plot shows a good spread of values, indicating no systematic bias between the methods. Quantitative lung perfusion can be obtained using the Fourier Decomposition method combined with a small amount of postprocessing. Copyright © 2013 Wiley Periodicals, Inc.

  18. Reduced-impact sliding pressure control valve for pneumatic hammer drill

    Science.gov (United States)

    Polsky, Yarom [Oak Ridge, TN; Grubelich, Mark C [Albuquerque, NM; Vaughn, Mark R [Albuquerque, NM

    2012-05-15

    A method and means of minimizing the effect of elastic valve recoil in impact applications, such as percussive drilling, where sliding spool valves used inside the percussive device are subject to poor positioning control due to elastic recoil effects experienced when the valve impacts a stroke limiting surface. The improved valve design reduces the reflected velocity of the valve by using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact.

  19. Process and device for reducing the pressure in the saftey containment of a nuclear reactor plant

    International Nuclear Information System (INIS)

    Stiefel, M.

    1984-01-01

    Part of the gaseous contents of the safety containment are drawn off. Hydrogen up to a maximum of 3.5% by volume is added to this gas. Part of the oxygen content of the gas is burnt with the hydrogen in the well-known way. The gas reduced in oxygen content is returned to the safety containment. The water produced in the reaction is taken back with the gas to the safety containment in the form of steam and is condensed there. (orig./HP) [de

  20. Goal-directed-perfusion in neonatal aortic arch surgery.

    Science.gov (United States)

    Cesnjevar, Robert Anton; Purbojo, Ariawan; Muench, Frank; Juengert, Joerg; Rueffer, André

    2016-07-01

    Reduction of mortality and morbidity in congenital cardiac surgery has always been and remains a major target for the complete team involved. As operative techniques are more and more standardized and refined, surgical risk and associated complication rates have constantly been reduced to an acceptable level but are both still present. Aortic arch surgery in neonates seems to be of particular interest, because perfusion techniques differ widely among institutions and an ideal form of a so called "total body perfusion (TBP)" is somewhat difficult to achieve. Thus concepts of deep hypothermic circulatory arrest (DHCA), regional cerebral perfusion (RCP/with cardioplegic cardiac arrest or on the perfused beating heart) and TBP exist in parallel and all carry an individual risk for organ damage related to perfusion management, chosen core temperature and time on bypass. Patient safety relies more and more on adequate end organ perfusion on cardiopulmonary bypass, especially sensitive organs like the brain, heart, kidney, liver and the gut, whereby on adequate tissue protection, temperature management and oxygen delivery should be visualized and monitored.

  1. Hepatic perfusion during hepatic artery infusion chemotherapy: Evaluation with perfusion CT and perfusion scintigraphy

    International Nuclear Information System (INIS)

    Miller, D.L.; Carrasquillo, J.A.; Lutz, R.J.; Chang, A.E.

    1989-01-01

    The standard method for the evaluation of hepatic perfusion during hepatic artery infusion (HAI) chemotherapy is planar hepatic artery perfusion scintigraphy (HAPS). Planar HAPS was performed with 2 mCi of [99mTc] macroaggregated albumin infused at 1 ml/min and compared with single photon emission CT (SPECT) HAPS and with a new study, CT performed during the slow injection of contrast material through the HAI catheter (HAI-CT). Thirteen patients underwent 16 HAI-CT studies, 14 planar HAPS studies, and 9 SPECT HAPS studies. In 13 of 14 studies (93%) HAI-CT and planar HAPS were in complete agreement as to the perfusion pattern of intrahepatic metastases and normal liver. In nine studies where all modalities were performed, the findings identified by HAI-CT and planar HAPS agreed in all cases, whereas the results of two SPECT scans disagreed with the other studies. With respect to perfusion of individual metastases, 14 of 14 HAI-CT studies, 12 of 13 planar HAPS studies, and 9 of 9 SPECT HAPS studies correctly demonstrated the perfusion status of individual lesions as indicated by the pattern of changes in tumor size determined on CT obtained before and after the perfusion studies. Hepatic artery infusion CT was superior for delineation of individual metastases, particularly small lesions, and for the evaluation of nonperfused portions of the liver. Planar HAPS detected extrahepatic perfusion in four patients, and this was not detected by HAI-CT. We conclude that HAI-CT and scintigraphy are complementary techniques. Hepatic artery infusion CT has advantages for the evaluation of intrahepatic perfusion, and planar HAPS is superior to HAI-CT for the detection of extrahepatic perfusion

  2. Methods to reduce intraocular pressure on secondary glaucoma after severe eye burns

    Directory of Open Access Journals (Sweden)

    A. V. Solovieva

    2014-07-01

    Full Text Available Purpose: Show the results of treatment of secondary glaucoma after severe eye burns.Methods: We observed 70 patients (108 eyes with severe burns the eyes and their consequences, secondary glaucoma was observed in 40 patients (58 eyes. All patients with secondary glaucoma received traditional antihypertensive therapy, with its failure to resort to antiglaucomatous surgery. Cataract extraction performed in 24 cases, 16 of them in combination with other surgery: the reconstruction of the anterior chamber, penetrating keratoplasty, sinustrabeculectomy, diode laser cyclocoagulation. Diode laser cy- clocoagulation performed 42 times in 8 of them in combination with other antiglaucomatous surgery: cataract surgery, reconstruction of the anterior chamber. Sinustrabeculectomy in patients with secondary glaucoma was performed in 7 cases, 4 of them with collagen implant drainage. Ahmed glaucoma drainage implant performed in 5 cases.Results: In 23 out of 58 (39.6% of long-term compensation glaucoma IOP was achieved antihypertensive therapy without sur- gery. After cataract extraction resistant compensated IOP was achieved in 10 cases, a temporary (1 to 42 months — in 11 cases, IOP is not reduced in 2 cases. After completing diode laser cyclocoagulation stable normalization of IOP occurred in 16 cases, the temporary (from 1 month to 2 years — in 20 cases, 4 cases of IOP reduction was not achieved. As a result sinustrabeculectomy in 4 cases IOP decreased, in one case the hypotensive effect is not there. After implantation Ahmed glaucoma valve in 2 cases was achieved stable normalization of IOP, in the 2 cases — the temporary; in 1 case developed endophthalmitis, and the device was removed.Conclusion: the immediate effect of antiglaucomatous treatment was 96.6%, but the high incidence of IOP decompensation (73.7% suggesting the need for continuous follow-up patients after severe eye burn injury, and a readiness to use other methods to reduce IOP.

  3. Methods to reduce intraocular pressure on secondary glaucoma after severe eye burns

    Directory of Open Access Journals (Sweden)

    A. V. Solovieva

    2012-01-01

    Full Text Available Purpose: Show the results of treatment of secondary glaucoma after severe eye burns.Methods: We observed 70 patients (108 eyes with severe burns the eyes and their consequences, secondary glaucoma was observed in 40 patients (58 eyes. All patients with secondary glaucoma received traditional antihypertensive therapy, with its failure to resort to antiglaucomatous surgery. Cataract extraction performed in 24 cases, 16 of them in combination with other surgery: the reconstruction of the anterior chamber, penetrating keratoplasty, sinustrabeculectomy, diode laser cyclocoagulation. Diode laser cy- clocoagulation performed 42 times in 8 of them in combination with other antiglaucomatous surgery: cataract surgery, reconstruction of the anterior chamber. Sinustrabeculectomy in patients with secondary glaucoma was performed in 7 cases, 4 of them with collagen implant drainage. Ahmed glaucoma drainage implant performed in 5 cases.Results: In 23 out of 58 (39.6% of long-term compensation glaucoma IOP was achieved antihypertensive therapy without sur- gery. After cataract extraction resistant compensated IOP was achieved in 10 cases, a temporary (1 to 42 months — in 11 cases, IOP is not reduced in 2 cases. After completing diode laser cyclocoagulation stable normalization of IOP occurred in 16 cases, the temporary (from 1 month to 2 years — in 20 cases, 4 cases of IOP reduction was not achieved. As a result sinustrabeculectomy in 4 cases IOP decreased, in one case the hypotensive effect is not there. After implantation Ahmed glaucoma valve in 2 cases was achieved stable normalization of IOP, in the 2 cases — the temporary; in 1 case developed endophthalmitis, and the device was removed.Conclusion: the immediate effect of antiglaucomatous treatment was 96.6%, but the high incidence of IOP decompensation (73.7% suggesting the need for continuous follow-up patients after severe eye burn injury, and a readiness to use other methods to reduce IOP.

  4. An eco design strategy for high pressure die casting components: microstructural analysis applied to mass reducing processes

    International Nuclear Information System (INIS)

    Suarez-Pena, B.; Asensio-Lozano, J.

    2009-01-01

    In this work the study focused on the possibility of use of new aluminium alloys with optimized microstructures that ensure the mechanical properties requested for cast components made by high pressure die casting. The objective was to check the possibility of manufacture of structurally sound eco-steps for escalators with reduced structural integrity. The former arises as a result of a new redesign of the traditional steps aiming at a significant weight reduction. The experimental results show that it is feasible to cut the use of materials during processing and therefore to reduce the impact of the components during its lifetime, whilst the performance and safety standards are kept identical or even improved. (Author) 17 refs

  5. Acute cerebral stroke imaging and brain perfusion with the use of high-concentration contrast media

    Energy Technology Data Exchange (ETDEWEB)

    Miles, K.A. [Wesley Research Inst., The Wesley Hospital, Brisbane (Australia); Brighton and Sussex Medical School, Univ. of Sussex, Falmer, Brighton (United Kingdom)

    2003-12-01

    Acute cerebral stroke remains a major cause of death among adults and the emergence of new therapies has created a need for early and rapid imaging at a time when conventional CT is either normal or demonstrates subtle abnormalities that are easy to misinterpret. Perfusion CT uses the temporal changes in cerebral and blood attenuation during a rapid series of images acquired without table movement following an intravenous bolus of contrast medium to generate images of mean transit time (MTT) cerebral blood volume (CBV) and perfusion. Reduced perfusion with preserved CBV is indicative of reversible ischaemia, whereas a matched reduction in perfusion and CBV implies infarction. The CT perfusion imaging can positively identify patients with non-haemorrhagic stroke in the presence of a normal conventional CT, provide an indication as to prognosis and potentially select those patients for whom thrombolysis is appropriate. Perfusion CT offers a powerful adjunct to MDCT based imaging of cerebrovascular disease, but further clinical validation is required. (orig.)

  6. How to reduce hospital-acquired pressure ulcers on a neuroscience unit with a skin and wound assessment team.

    Science.gov (United States)

    McGuinness, Janice; Persaud-Roberts, Sherry; Marra, Susan; Ramos, Jeannine; Toscano, Diane; Policastro, Linda; Epstein, Nancy E

    2012-01-01

    In 2008, the incidence of hospital acquired pressure ulcers (HAPUs) continued to increase on a neuroscience unit that included both neurosurgical and neurological patients in a 14-bed intensive care unit, and in a 18-bed floor unit. To reduce HAPUs, several changes were instituted in 2008; (1) turning patients every 1-2 h/repositioning, (2) specialty beds, and (3) a "skin and wound assessment team (SWAT)" that included one (or two) "expert" nurses/nursing assistants who made rounds on all the patients in the unit at least once a week. They would examine patients from "head to toe", document/measure all pressure ulcers, and educate primary nurses/nurse assistants on the plan/products needed for the patients wound care based on their assessments. In 2010, further measures included: (1) adding eight Stryker beds, (2) adding pressure relieving heel protector boots, and (3) requiring that all new hospital orientees work one shift (7.5 h) shadowing the SWAT team. The SWAT team initially decreased HAPUs by 48% in 2009; this reduction was further increased in 2010 (57%), and 2011 (61%). Additionally, in 2010, the SWAT team was required to educate nurses in all other units. By 2011, all nurses had to complete the hospital acquired pressure ulcer prevention tutorial. Since instituting a specialized SWAT team for our neuroscience unit, the incidence of HAPUs (cost estimated for grade IV, US $129,248) was decreased by 48% in 2009, by 57% in 2010, and by 61% in 2011. The SWAT program is now hospital-wide.

  7. Resistance training alone reduces systolic and diastolic blood pressure in prehypertensive and hypertensive individuals: meta-analysis.

    Science.gov (United States)

    de Sousa, Evitom Corrêa; Abrahin, Odilon; Ferreira, Ana Lorena Lima; Rodrigues, Rejane Pequeno; Alves, Erik Artur Cortinhas; Vieira, Rodolfo Paula

    2017-11-01

    The purpose of this study was to evaluate the effects of resistance training alone on the systolic and diastolic blood pressure in prehypertensive and hypertensive individuals. Our meta-analysis, followed the guidelines of PRISMA. The search for articles was realized by November 2016 using the following electronic databases: BIREME, PubMed, Cochrane Library, LILACS and SciELO and a search strategy that included the combination of titles of medical affairs and terms of free text to the key concepts: 'hypertension' 'hypertensive', 'prehypertensive', 'resistance training', 'strength training', and 'weight-lifting'. These terms were combined with a search strategy to identify randomized controlled trials (RCTs) and identified a total of 1608 articles: 644 articles BIREME, 53 SciELO, 722 PubMed, 122 Cochrane Library and 67 LILACS. Of these, five RCTs met the inclusion criteria and provided data on 201 individuals. The results showed significant reductions for systolic blood pressure (-8.2 mm Hg CI -10.9 to -5.5;I 2 : 22.5% P valor for heterogeneity=0.271 and effect size=-0.97) and diastolic blood pressure (-4.1 mm Hg CI -6.3 to -1.9; I 2 : 46.5% P valor for heterogeneity=0.113 and effect size=-0.60) when compared to group control. In conclusion, resistance training alone reduces systolic and diastolic blood pressure in prehypertensive and hypertensive subjects. The RCTs studies that investigated the effects of resistance training alone in prehypertensive and hypertensive patients support the recommendation of resistance training as a tool for management of systemic hypertension.

  8. Arctigenin reduces blood pressure by modulation of nitric oxide synthase and NADPH oxidase expression in spontaneously hypertensive rats.

    Science.gov (United States)

    Liu, Ying; Wang, Guoyuan; Yang, Mingguang; Chen, Haining; zhao, Yan; Yang, Shucai; Sun, Changhao

    2015-12-25

    Arctigenin is a bioactive constituent from dried seeds of Arctium lappa L., which was traditionally used as medicine. Arctigenin exhibits various bioactivities, but its effects on blood pressure regulation are still not widely studied. In this study, we investigated antihypertensive effects of arctigenin by long-term treatment in spontaneously hypertensive rats (SHRs). Arctigenin (50 mg/kg) or vehicle was administered to SHRs or Wistar rats as negative control by oral gavage once a day for total 8 weeks. Nifedipine (3 mg/kg) was used as a positive drug control. After treatment, hemodynamic and physical parameters, vascular reactivity in aorta, the concentration of plasma arctigenin and serum thromboxane B2, NO release and vascular p-eNOS, p-Akt, caveolin-1 protein expression, and vascular superoxide anion generation and p47phox protein expression were detected and analyzed. The results showed that arctigenin significantly reduced systolic blood pressure and ameliorated endothelial dysfunction of SHRs. Arctigenin reduced the levels of thromboxane B2 in plasma and superoxide anion in thoracic aorta of SHRs. Furthermore, arctigenin increased the NO production by enhancing the phosphorylation of Akt and eNOS (Ser 1177), and inhibiting the expression of NADPH oxidase in thoracic aorta of SHRs. Our data suggested that antihypertensive mechanisms of arctigenin were associated with enhanced eNOS phosphorylation and decreased NADPH oxidase-mediated superoxide anion generation. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. A model for calculation of RCS pressure during reflux boiling under reduced inventory conditions and its assessment against PKL data

    International Nuclear Information System (INIS)

    Palmrose, D.E.; Mandl, R.

    1991-01-01

    Based on the occurrence of a number of plant incidents during low power and shutdown operating conditions, the Nuclear Regulatory Commission (NRC) has initiated several programs to better quantify risk during these periods. One specific issue of interest is the loss of residual heat removal (RHR) under reduced coolant inventory conditions. This issue is also of interest in the Federal Republic of Germany and an experiment was performed in the integral PKL-3 experimental facility at Siemens-KWU to supply applicable data. Recently, an effort has been undertaken at the Idaho National Engineering Laboratory (INEL) to identify and analyze the important thermal-hydraulic phenomena in pressurized water reactors following loss of vital AC power and consequent loss of the RHR system during reduced inventory operation. The thermal-hydraulic response of a nuclear steam supply system (NSSS) with a closed reactor coolant system (RCS) to loss of residual heat removal cooling capability is investigated in this report. The specific processes investigated include: boiling of the coolant in the core and reflux condensation in the steam generators, the corresponding pressure increase in the reactor coolant system, the heat transfer mechanisms on the primary and secondary sides of the steam generators, the effects of air or other noncondensible gas on the heat transfer processes, and void fraction distributions on the primary side of the system. Mathematical models of these physical processes were developed and validated against experimental data from the PKL 3B 4.5 Experiment

  10. Antenatal hypoxia induces programming of reduced arterial blood pressure response in female rat offspring: role of ovarian function.

    Directory of Open Access Journals (Sweden)

    DaLiao Xiao

    Full Text Available In utero exposure to adverse environmental factors increases the risk of cardiovascular disease in adulthood. The present study tested the hypothesis that antenatal hypoxia causes a gender-dependent programming of altered arterial blood pressure response (BP in adult offspring. Time-dated pregnant rats were divided into normoxic and hypoxic (10.5% O2 from days 15 to 21 of gestation groups. The experiments were conducted in adult offspring. Antenatal hypoxia caused intrauterine growth restriction, and resulted in a gender-dependent increase Angiotensin II (Ang II-induced BP response in male offspring, but significant decrease in BP response in female offspring. The baroreflex sensitivity was not significantly altered. Consistent with the reduced blood pressure response, antenatal hypoxia significantly decreased Ang II-induced arterial vasoconstriction in female offspring. Ovariectomy had no significant effect in control animals, but significantly increased Ang II-induced maximal BP response in prenatally hypoxic animals and eliminated the difference of BP response between the two groups. Estrogen replacement in ovariectomized animals significantly decreased the BP response to angiotensin II I only in control, but not in hypoxic animals. The result suggests complex programming mechanisms of antenatal hypoxia in regulation of ovary function. Hypoxia-mediated ovary dysfunction results in the phenotype of reduced vascular contractility and BP response in female adult offspring.

  11. Transient influence of end-tidal carbon dioxide tension on the postural restraint in cerebral perfusion

    DEFF Research Database (Denmark)

    Immink, R.V.; Truijen, J.; Secher, Niels H.

    2009-01-01

    In the upright position, cerebral blood flow is reduced, maybe because arterial carbon dioxide partial pressure (Pa(CO(2))) decreases. We evaluated the time-dependent influence of a reduction in Pa(CO(2)), as indicated by the end-tidal Pco(2) tension (Pet(CO(2))), on cerebral perfusion during head......-up tilt. Mean arterial pressure, cardiac output, middle cerebral artery mean flow velocity (MCA V(mean)), and dynamic cerebral autoregulation at supine rest and 70 degrees head-up tilt were determined during free breathing and with Pet(CO(2)) clamped to the supine level. The postural changes in central...... hemodynamic variables were equivalent, and the cerebrovascular autoregulatory capacity was not significantly affected by tilt or by clamping Pet(CO(2)). In the first minute of tilt, the decline in MCA V(mean) (10 +/- 4 vs. 3 +/- 4 cm/s; mean +/- SE; P

  12. High-nitrate vegetable diet increases plasma nitrate and nitrite concentrations and reduces blood pressure in healthy women.

    Science.gov (United States)

    Ashworth, Ann; Mitchell, Klaus; Blackwell, Jamie R; Vanhatalo, Anni; Jones, Andrew M

    2015-10-01

    Epidemiological studies suggest that green leafy vegetables, which are high in dietary nitrate, are protective against CVD such as stroke. High blood pressure (BP) is a major risk factor for stroke and inorganic nitrate has been shown to reduce BP. The objective of the present study was to test the hypothesis that diets containing high-nitrate (HN) vegetables would increase plasma nitrate and nitrite concentrations and reduce BP in healthy women. A randomized, crossover trial, where participants received HN vegetables (HN diet) or avoided HN vegetables (Control diet) for 1 week. Before and after each intervention, resting BP and plasma nitrate and nitrite concentrations were measured. University of Exeter, UK. Nineteen healthy women (mean age 20 (sd 2) years; mean BMI 22·5 (sd 3·8) kg/m2). The HN diet significantly increased plasma nitrate concentration (before HN diet: mean 24·4 (sd 5·6) µmol/l; after HN diet: mean 61·0 (sd 44·1) µmol/l, Pdiet: mean 98 (sd 91) nmol/l; after HN diet: mean 185 (sd 34) nmol/l, Pdiet. The HN diet significantly reduced resting systolic BP (before HN diet: mean 107 (sd 9) mmHg; after HN diet: mean 103 (sd 6) mmHg, Pdiet (before Control diet: mean 106 (sd 8) mmHg; after Control diet: mean 106 (sd 8) mmHg). Consumption of HN vegetables significantly increased plasma nitrate and nitrite concentrations and reduced BP in normotensive women.

  13. Reactivity of the isolated perfused rat tail vascular bed

    Directory of Open Access Journals (Sweden)

    A.S. França

    1997-07-01

    Full Text Available Isolated segments of the perfused rat tail artery display a high basal tone when compared to other isolated arteries such as the mesenteric and are suitable for the assay of vasopressor agents. However, the perfusion of this artery in the entire tail has not yet been used for functional studies. The main purpose of the present study was to identify some aspects of the vascular reactivity of the rat tail vascular bed and validate this method to measure vascular reactivity. The tail severed from the body was perfused with Krebs solution containing different Ca2+ concentrations at different flow rates. Rats were anesthetized with sodium pentobarbital (65 mg/kg and heparinized (500 U. The tail artery was dissected near the tail insertion, cannulated and perfused with Krebs solution plus 30 µM EDTA at 36oC and 2.5 ml/min and the procedures were started after equilibration of the perfusion pressure. In the first group a dose-response curve to phenylephrine (PE (0.5, 1, 2 and 5 µg, bolus injection was obtained at different flow rates (1.5, 2.5 and 3.5 ml/min. The mean perfusion pressure increased with flow as well as PE vasopressor responses. In a second group the flow was changed (1.5, 2, 2.5, 3 and 3.5 ml/min at different Ca2+ concentrations (0.62, 1.25, 2.5 and 3.75 mM in the Krebs solution. Increasing Ca2+ concentrations did not alter the flow-pressure relationship. In the third group a similar protocol was performed but the rat tail vascular bed was perfused with Krebs solution containing PE (0.1 µg/ml. There was an enhancement of the effect of PE with increasing external Ca2+ and flow. PE vasopressor responses increased after endothelial damage with air and CHAPS, suggesting an endothelial modulation of the tone of the rat tail vascular bed. These experiments validate the perfusion of the rat tail vascular bed as a method to investigate vascular reactivity

  14. Characterization of micro-invasive trabecular bypass stents by ex vivo perfusion and computational flow modeling

    Directory of Open Access Journals (Sweden)

    Hunter KS

    2014-03-01

    Full Text Available Kendall S Hunter,1 Todd Fjield,2 Hal Heitzmann,2 Robin Shandas,1 Malik Y Kahook3 1Department of Bioengineering, University of Colorado Denver, Aurora, CO, USA; 2Glaukos Corporation, Laguna Hills, CA, USA; 3University of Colorado Hospital Eye Center, Aurora, CO, USA Abstract: Micro-invasive glaucoma surgery with the Glaukos iStent® or iStent inject® (Glaukos Corporation, Laguna Hills, CA, USA is intended to create a bypass through the trabecular meshwork to Schlemm's canal to improve aqueous outflow through the natural physiologic pathway. While the iStent devices have been evaluated in ex vivo anterior segment models, they have not previously been evaluated in whole eye perfusion models nor characterized by computational fluid dynamics. Intraocular pressure (IOP reduction with the iStent was evaluated in an ex vivo whole human eye perfusion model. Numerical modeling, including computational fluid dynamics, was used to evaluate the flow through the stents over physiologically relevant boundary conditions. In the ex vivo model, a single iStent reduced IOP by 6.0 mmHg from baseline, and addition of a second iStent further lowered IOP by 2.9 mmHg, for a total IOP reduction of 8.9 mmHg. Computational modeling showed that simulated flow through the iStent or iStent inject is smooth and laminar at physiological flow rates. Each stent was computed to have a negligible flow resistance consistent with an expected significant decrease in IOP. The present perfusion results agree with prior clinical and laboratory studies to show that both iStent and iStent inject therapies are potentially titratable, providing clinicians with the opportunity to achieve lower target IOPs by implanting additional stents. Keywords: glaucoma, iStent, trabecular bypass, intraocular pressure, ab-interno, CFD

  15. Edaravone inhibits pressure overload-induced cardiac fibrosis and dysfunction by reducing expression of angiotensin II AT1 receptor

    Directory of Open Access Journals (Sweden)

    Zhang WW

    2017-10-01

    Full Text Available Wei-Wei Zhang,1,2 Feng Bai,1 Jin Wang,1 Rong-Hua Zheng,1 Li-Wang Yang,1 Erskine A James,3 Zhi-Qing Zhao1,4 1Department of Physiology, Shanxi Medical University, 2Department of Anesthesiology, Shanxi Provincial People’s Hospital, Taiyuan, Shanxi, China; 3Department of Internal Medicine, Navicent Health, Macon, 4Department of Basic Biomedical Sciences, Mercer University School of Medicine, Savannah, GA, USA Abstract: Angiotensin II (Ang II is known to be involved in the progression of ventricular dysfunction and heart failure by eliciting cardiac fibrosis. The purpose of this study was to demonstrate whether treatment with an antioxidant compound, edaravone, reduces cardiac fibrosis and improves ventricular function by inhibiting Ang II AT1 receptor. The study was conducted in a rat model of transverse aortic constriction (TAC. In control, rats were subjected to 8 weeks of TAC. In treated rats, edaravone (10 mg/kg/day or Ang II AT1 receptor blocker, telmisartan (10 mg/kg/day was administered by intraperitoneal injection or gastric gavage, respectively, during TAC. Relative to the animals with TAC, edaravone reduced myocardial malonaldehyde level and increased superoxide dismutase activity. Protein level of the AT1 receptor was reduced and the AT2 receptor was upregulated, as evidenced by the reduced ratio of AT1 over AT2 receptor (0.57±0.2 vs 3.16±0.39, p<0.05 and less locally expressed AT1 receptor in the myocardium. Furthermore, the protein level of angiotensin converting enzyme 2 was upregulated. In coincidence with these changes, edaravone significantly decreased the populations of macrophages and myofibroblasts in the myocardium, which were accompanied by reduced levels of transforming growth factor beta 1 and Smad2/3. Collagen I synthesis was inhibited and collagen-rich fibrosis was attenuated. Relative to the TAC group, cardiac systolic function was preserved, as shown by increased left ventricular systolic pressure (204±51 vs 110±19

  16. Low-Dose Dextromethorphan, a NADPH Oxidase Inhibitor, Reduces Blood Pressure and Enhances Vascular Protection in Experimental Hypertension

    Science.gov (United States)

    Wu, Tao-Cheng; Chao, Chih-Yu; Lin, Shing-Jong; Chen, Jaw-Wen

    2012-01-01

    Background Vascular oxidative stress may be increased with age and aggravate endothelial dysfunction and vascular injury in hypertension. This study aimed to investigate the effects of dextromethorphan (DM), a NADPH oxidase inhibitor, either alone or in combination treatment, on blood pressure (BP) and vascular protection in aged spontaneous hypertensive rats (SHRs). Methodology/Principal Findings Eighteen-week-old WKY rats and SHRs were housed for 2 weeks. SHRs were randomly assigned to one of the 12 groups: untreated; DM monotherapy with 1, 5 or 25 mg/kg/day; amlodipine (AM, a calcium channel blocker) monotherapy with 1 or 5 mg/kg/day; and combination therapy of DM 1, 5 or 25 mg/kg/day with AM 1 or 5 mg/kg/day individually for 4 weeks. The in vitro effects of DM were also examined. In SHRs, AM monotherapy dose-dependently reduced arterial systolic BP. DM in various doses significantly and similarly reduced arterial systolic BP. Combination of DM with AM gave additive effects on BP reduction. DM, either alone or in combination with AM, improved aortic endothelial function indicated by ex vivo acetylcholine-induced relaxation. The combination of low-dose DM with AM gave most significant inhibition on aortic wall thickness in SHRs. Plasma total antioxidant status was significantly increased by all the therapies except for the combination of high-dose DM with high-dose AM. Serum nitrite and nitrate level was significantly reduced by AM but not by DM or the combination of DM with AM. Furthermore, in vitro treatment with DM reduced angiotensin II-induced reactive oxygen species and NADPH oxidase activation in human aortic endothelial cells. Conclusions/Significance Treatment of DM reduced BP and enhanced vascular protection probably by inhibiting vascular NADPH oxidase in aged hypertensive animals with or without AM treatment. It provides the potential rationale to a novel combination treatment with low-dose DM and AM in clinical hypertension. PMID:23049937

  17. Low-dose dextromethorphan, a NADPH oxidase inhibitor, reduces blood pressure and enhances vascular protection in experimental hypertension.

    Directory of Open Access Journals (Sweden)

    Tao-Cheng Wu

    Full Text Available BACKGROUND: Vascular oxidative stress may be increased with age and aggravate endothelial dysfunction and vascular injury in hypertension. This study aimed to investigate the effects of dextromethorphan (DM, a NADPH oxidase inhibitor, either alone or in combination treatment, on blood pressure (BP and vascular protection in aged spontaneous hypertensive rats (SHRs. METHODOLOGY/PRINCIPAL FINDINGS: Eighteen-week-old WKY rats and SHRs were housed for 2 weeks. SHRs were randomly assigned to one of the 12 groups: untreated; DM monotherapy with 1, 5 or 25 mg/kg/day; amlodipine (AM, a calcium channel blocker monotherapy with 1 or 5 mg/kg/day; and combination therapy of DM 1, 5 or 25 mg/kg/day with AM 1 or 5 mg/kg/day individually for 4 weeks. The in vitro effects of DM were also examined. In SHRs, AM monotherapy dose-dependently reduced arterial systolic BP. DM in various doses significantly and similarly reduced arterial systolic BP. Combination of DM with AM gave additive effects on BP reduction. DM, either alone or in combination with AM, improved aortic endothelial function indicated by ex vivo acetylcholine-induced relaxation. The combination of low-dose DM with AM gave most significant inhibition on aortic wall thickness in SHRs. Plasma total antioxidant status was significantly increased by all the therapies except for the combination of high-dose DM with high-dose AM. Serum nitrite and nitrate level was significantly reduced by AM but not by DM or the combination of DM with AM. Furthermore, in vitro treatment with DM reduced angiotensin II-induced reactive oxygen species and NADPH oxidase activation in human aortic endothelial cells. CONCLUSIONS/SIGNIFICANCE: Treatment of DM reduced BP and enhanced vascular protection probably by inhibiting vascular NADPH oxidase in aged hypertensive animals with or without AM treatment. It provides the potential rationale to a novel combination treatment with low-dose DM and AM in clinical hypertension.

  18. n-3 fatty acids reduce plasma 20-hydroxyeicosatetraenoic acid and blood pressure in patients with chronic kidney disease.

    Science.gov (United States)

    Barden, Anne E; Burke, Valerie; Mas, Emilie; Beilin, Lawrence J; Puddey, Ian B; Watts, Gerald F; Irish, Ashley B; Mori, Trevor A

    2015-09-01

    Metabolism of arachidonic acid by cytochrome P450 ω-hydroxylase leads to the formation of 20-hydroxyeicosatetraenoic acid (20-HETE) that regulates vascular function, sodium homeostasis and blood pressure (BP). Supplementation with n-3 fatty acids is known to alter arachidonic acid metabolism and reduce the formation of the lipid peroxidation products F2-isoprostanes, but the effect of n-3 fatty acids on 20-HETE has not been studied. We previously reported a significant effect of n-3 fatty acids but not coenzyme Q10 (CoQ) to reduce BP in a double-blind, placebo-controlled intervention, wherein patients with chronic kidney disease (CKD) were randomized to n-3 fatty acids (4 g), CoQ (200 mg), both supplements or control (4 g olive oil), daily for 8 weeks. This study examined the effect of n-3 fatty acids on plasma and urinary 20-HETE in the same study, as well as plasma and urinary F2-isoprostanes, and relate these to changes in BP. Seventy-four patients completed the 8-week intervention. n-3 fatty acids but not CoQ significantly reduced plasma 20-HETE (P = 0.001) and F2-isoprostanes (P fatty acids. This is the first report that n-3 fatty acid supplementation reduces plasma 20-HETE in humans and that this associates with reduced BP. These results provide a plausible mechanism for the reduction in BP observed in patients with CKD following n-3 fatty acid supplementation.

  19. The impact of high hydrostatic pressure on the functionality and consumer acceptability of reduced sodium naturally cured wieners.

    Science.gov (United States)

    Pietrasik, Z; Gaudette, N J; Johnston, S P

    2017-07-01

    The effects of high pressure processing (HPP; 600MPa for 3min at 8°C) on the quality and shelf life of reduced sodium naturally-cured wieners was studied. HPP did not negatively impact processing characteristics and assisted in extending shelf life of all wiener treatments up to a 12week storage period. At week 8, HPP wieners received higher acceptability scores, indicating HPP can effectively extend the sensory quality of products, including sodium reduced formulations containing natural forms of nitrite. Substitution of 50% NaCl with modified KCl had negative effect on textural characteristics of conventionally cured wieners but not those processed with celery powder as a source of nitrite. Celery powder favorably affected hydration of textural properties of wieners, and consumer acceptability of juiciness and texture was higher compared to nitrite. Sodium reduction, independent of curing agent, negatively impacted flavor acceptability, while only nitrite containing reduced sodium wieners scored significantly lower than both regular salt wieners for texture, juiciness and saltiness. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Chemical vapour deposition of silicon under reduced pressure in a hot-wall reactor: Equilibrium and kinetics

    International Nuclear Information System (INIS)

    Langlais, F.; Hottier, F.; Cadoret, R.

    1982-01-01

    Silicon chemical vapour deposition (SiH 2 Cl 2 /H 2 system), under reduced pressure conditions, in a hot-wall reactor, is presented. The vapour phase composition is assessed by evaluating two distinct equilibria. The homogeneous equilibrium , which assumes that the vapour phase is not in equilibrium with solid silicon, is thought to give an adequate description of the vapour phase in the case of low pressure, high gas velocities, good temperature homogeneity conditions. A comparison with heterogeneous equilibrium enables us to calculate the supersaturation so evidencing a highly irreversible growth system. The experimental determination of the growth rates reveals two distinct temperature ranges: below 1000 0 C, polycrystalline films are usually obtained with a thermally activated growth rate (+40 kcal mole -1 ) and a reaction order, with respect to the predominant species SiCl 2 , close to one; above 1000 0 C, the films are always monocrystalline and their growth rate exhibits a much lower or even negative activation energy, the reaction order in SiCl 2 remaining about one. (orig.)

  1. Control of substrate oxidation in MOD cerawwwmic coating on low-activation ferritic steel with reduced-pressure atmosphere

    Science.gov (United States)

    Tanaka, Teruya; Muroga, Takeo

    2014-12-01

    An Er2O3 ceramic coating fabricated using the metal-organic decomposition (MOD) method on a Cr2O3-covered low-activation ferritic steel JLF-1 substrate was examined to improve hydrogen permeation barrier performance of the coating. The Cr2O3 layer was obtained before coating by heat treating the substrate at 700 °C under reduced pressures of baking. Preprocessing to obtain a Cr2O3 layer would provide flexibility in the coating process for blanket components and ducts. Moreover, the Cr2O3 layer suppressed hydrogen permeation through the JLF-1 substrate. While further optimization of the coating fabrication process is required, it would be possible to suppress hydrogen permeation significantly by multilayers of Cr2O3 and MOD oxide ceramic.

  2. Early application of airway pressure release ventilation may reduce the duration of mechanical ventilation in acute respiratory distress syndrome.

    Science.gov (United States)

    Zhou, Yongfang; Jin, Xiaodong; Lv, Yinxia; Wang, Peng; Yang, Yunqing; Liang, Guopeng; Wang, Bo; Kang, Yan

    2017-11-01

    Experimental animal models of acute respiratory distress syndrome (ARDS) have shown that the updated airway pressure release ventilation (APRV) methodologies may significantly improve oxygenation, maximize lung recruitment, and attenuate lung injury, without circulatory depression. This led us to hypothesize that early application of APRV in patients with ARDS would allow pulmonary function to recover faster and would reduce the duration of mechanical ventilation as compared with low tidal volume lung protective ventilation (LTV). A total of 138 patients with ARDS who received mechanical ventilation for mechanical ventilation from enrollment to day 28. The secondary endpoints included oxygenation, P plat , respiratory system compliance, and patient outcomes. Compared with the LTV group, patients in the APRV group had a higher median number of ventilator-free days {19 [interquartile range (IQR) 8-22] vs. 2 (IQR 0-15); P mechanical ventilation and ICU stay.

  3. A self-ordered, body-centered tetragonal superlattice of SiGe nanodot growth by reduced pressure CVD

    Science.gov (United States)

    Yamamoto, Yuji; Zaumseil, Peter; Capellini, Giovanni; Schubert, Markus Andreas; Hesse, Anne; Albani, Marco; Bergamaschini, Roberto; Montalenti, Francesco; Schroeder, Thomas; Tillack, Bernd

    2017-12-01

    Self-ordered three-dimensional body-centered tetragonal (BCT) SiGe nanodot structures are fabricated by depositing SiGe/Si superlattice layer stacks using reduced pressure chemical vapor deposition. For high enough Ge content in the island (>30%) and deposition temperature of the Si spacer layers (T > 700 °C), we observe the formation of an ordered array with islands arranged in staggered position in adjacent layers. The in plane periodicity of the islands can be selected by a suitable choice of the annealing temperature before the Si spacer layer growth and of the SiGe dot volume, while only a weak influence of the Ge concentration is observed. Phase-field simulations are used to clarify the driving force determining the observed BCT ordering, shedding light on the competition between heteroepitaxial strain and surface-energy minimization in the presence of a non-negligible surface roughness.

  4. (−-Epicatechin Reduces Blood Pressure and Improves Left Ventricular Function and Compliance in Deoxycorticosterone Acetate-Salt Hypertensive Rats

    Directory of Open Access Journals (Sweden)

    Douglas Jackson

    2018-06-01

    Full Text Available (−-Epicatechin (E is a flavanol found in green tea and cocoa and has been shown to attenuate tumour necrosis factor alpha (TNF-α-mediated inflammation, improve nitric oxide levels, promote endothelial nitric oxide synthase (eNOS activation and inhibit NADPH oxidase. This study investigated the effect of 28 days of low epicatechin dosing (1 mg/kg/day on the cardiovascular function of deoxycorticosterone acetate (DOCA-salt hypertensive rats. Wistar rats (n = 120, 8 weeks of age underwent uninephrectomy and were randomised into four groups (uninephrectomy (UNX, UNX + E, DOCA, DOCA + E. DOCA and DOCA + E rats received 1% NaCl drinking water along with subcutaneous injections of 25 mg deoxycorticosterone-acetate (in 0.4 mL of dimethylformamide every fourth day. UNX + E and DOCA + E rats received 1 mg/kg/day of epicatechin by oral gavage. Single-cell micro-electrode electrophysiology, Langendorff isolated-heart assessment and isolated aorta and mesenteric organ baths were used to assess cardiovascular parameters. Serum malondialdehyde concentration was used as a marker of oxidative stress. Myocardial stiffness was increased and left ventricular compliance significantly diminished in the DOCA control group, and these changes were attenuated by epicatechin treatment (p < 0.05. Additionally, the DOCA + E rats showed significantly reduced blood pressure and malondialdehyde concentrations; however, there was no improvement in left ventricular hypertrophy, electrophysiology or vascular function. This study demonstrates the ability of epicatechin to reduce blood pressure, prevent myocardial stiffening and preserve cardiac compliance in hypertrophied DOCA-salt rat hearts.

  5. Fluctuation-Coupling of Cathode Cavity Pressure and Arc Voltage in a dc Plasma Torch with a Long Inter-Electrode Channel at Reduced Pressure

    International Nuclear Information System (INIS)

    Cao Jin-Wen; Huang He-Ji; Pan Wen-Xia

    2014-01-01

    Fluctuations of cathode cavity pressure and arc voltage are observed experimentally in a dc plasma torch with a long inter-electrode channel. The results show that they have the same frequency of around 4 kHz under typical experimental conditions. The observed phase difference between the pressure and the voltage, which is influenced by the path length between the pressure sensor and the cathode cavity, varies with different input powers. Combined with numerical simulation, the position of the pressure perturbation origin is estimated, and the results show that it is located at 0.01–0.05 m upstream of the inter-electrode channel outlet

  6. [Intratympanic corticosteroid perfusion in the therapy of Meniere's disease].

    Science.gov (United States)

    Sanković-Babić, Snezana; Kosanović, Rade; Ivanković, Zoran; Babac, Snezana; Tatović, Milica

    2014-01-01

    Over the last two decades the intratympanic perfusion of corticosteroids has been used as a minimally invasive surgical therapy of Meniere's disease. According to experimental studies the antiinflammatory, immunoprotective, antioxidant and neuroprotective role of the locally perfused corticosteroids was noticed in the inner ear structures. The recovery of action potentials in the cells of the Corti organ was confirmed as well as a decreased expression of aquaporine-1, a glycoprotein responsible for labyrinth hydrops and N and K ions derangement. The study showed results of intratympanic perfusion therapy with dexamethasone in patients with retractable Meniere's disease who are resistant to conservative treatment. Single doses of 4 mg/ml dexamethasone were given intratympanically in 19 patients with retractable Meniere's disease. Six single successive doses of dexamethasone were administered in the posteroinferior quadrant of the tympanic membrane. Follow-up of the patients was conducted by using a clinical questionnaire a month after completed perfusion series as well as on every third month up to one year. One month after completed first course of perfusions, in 78% of patients, vertigo problems completely ceased or were markedly reduced. The recovery of hearing function was recorded in 68% and marked tinnitus reduction in 84% of patients. After a year of follow-up, in 63% of patients the reduction of vertigo persisted, while hearing function was satisfactory in 52%. Tinitus reduction was present in 73% of patients. Intratympanic perfusion of dexamethasone in patients with Meniere's disease is a minimally invasive therapeutic method that contributes to the reduction of the intensity of vertigo recurrent attacks, decrease of the intensity of tinnitus and improvement of the average hearing threshold. Patients with chronic diseases and Meniere's disease who are contraindicted for systemic administration of cortocosteroids (hypertension, diabetes, glaucoma, peptic

  7. Palmitoylethanolamide treatment reduces blood pressure in spontaneously hypertensive rats: involvement of cytochrome p450-derived eicosanoids and renin angiotensin system.

    Directory of Open Access Journals (Sweden)

    Giuseppina Mattace Raso

    Full Text Available Palmitoylethanolamide (PEA, a peroxisome proliferator-activated receptor-α agonist, has been demonstrated to reduce blood pressure and kidney damage secondary to hypertension in spontaneously hypertensive rat (SHR. Currently, no information is available concerning the putative effect of PEA on modulating vascular tone. Here, we investigate the mechanisms underpinning PEA blood pressure lowering effect, exploring the contribution of epoxyeicosatrienoic acids, CYP-dependent arachidonic acid metabolites, as endothelium-derived hyperpolarizing factors (EDHF, and renin angiotensin system (RAS modulation. To achieve this aim SHR and Wistar-Kyoto rats were treated with PEA (30 mg/kg/day for five weeks. Functional evaluations on mesenteric bed were performed to analyze EDHF-mediated vasodilation. Moreover, mesenteric bed and carotid were harvested to measure CYP2C23 and CYP2J2, the key isoenzymes in the formation of epoxyeicosatrienoic acids, and the soluble epoxide hydrolase, which is responsible for their degradation in the corresponding diols. Effect of PEA on RAS modulation was investigated by analyzing angiotensin converting enzyme and angiotensin receptor 1 expression. Here, we showed that EDHF-mediated dilation in response to acetylcholine was increased in mesenteric beds of PEA-treated SHR. Western blot analysis revealed that the increase in CYP2C23 and CYP2J2 observed in SHR was significantly attenuated in mesenteric beds of PEA-treated SHR, but unchanged in the carotids. Interestingly, in both vascular tissues, PEA significantly decreased the soluble epoxide hydrolase protein level, accompanied by a reduced serum concentration of its metabolite 14-15 dihydroxyeicosatrienoic acid, implying a reduction in epoxyeicosatrienoic acid hydrolisis. Moreover, PEA treatment down-regulated angiotensin receptor 1 and angiotensin converting enzyme expression, indicating a reduction in angiotensin II-mediated effects. Consistently, a damping of the

  8. Value and limitation of digital subtraction angiography for assessment of myocardial perfusion with varying coronary stenosis

    International Nuclear Information System (INIS)

    Ohtani, Nozomu

    1988-01-01

    We examined the value of digital subtraction angiography (DSA) for the assessment of regional myocardial perfusion by comparing with regional myocardial function in 10 anesthetized dogs. With varying degrees of reduction in left circumflex coronary artery (LCX) blood flow (CBF:categories of stenosis (S1-S5)), myocardial perfusion was assessed by injecting the contrast medium(1ml by power injector) selectively into LCX, and the regional myocardium with contrast was imaged with DSA. We recorded aortic pressure (AOP) and systolic wall thickening (%WTh: sonomicrometry) in the left ventricular posterior wall simultaneously with cine pulse. On the time-density curve obtained from the myocardial regin of interest, we calculated a time interval from the contrast injection to peak concentration (TPC) and exponential washout rate (T). Under varying LCX stenosis, there were no significant change of heart rate and mean AOP and a significant linear correlations were found between %WTh and both 1/TPC(r=0.51)and 1/T(r=0.55). At S1(CBF:100-90% of control), neither %WTh nor 1/TPC differed from control, but 1/T was significantly decreased (80% of contral p<0.01). At S3(CRF:79-60%) to S5(CBF:39-0%), all%WTh, 1/TPC and 1/T were significantly decreased from control (all p<0.01), however, at S5(CBF:39-0%) the value of 1/TPC(71% of control) and 1/T(33%) were not different from that at S4, whereas %WTh was markedly reduced and took place to systolic thinning.. Therefore, in critical coronary stenosis, 1/T was more sensitive than 1/TPC or wall dynamics for assessing myocardial perfusion, however, these indices from DSA had a considerable limitation for evaluating the severity of myocardial ischemia when CBF was markedly reduced. (author)

  9. Machine Perfusion of Porcine Livers with Oxygen-Carrying Solution Results in Reprogramming of Dynamic Inflammation Networks

    Directory of Open Access Journals (Sweden)

    David Sadowsky

    2016-11-01

    Full Text Available Background: Ex vivo machine perfusion (MP can better preserve organs for transplantation. We have recently reported on the first application of a MP protocol in which liver allografts were fully oxygenated, under dual pressures and subnormothermic conditions, with a new hemoglobin-based oxygen carrier solution specifically developed for ex vivo utilization. In those studies, MP improved organ function post-operatively and reduced inflammation in porcine livers. Herein, we sought to refine our knowledge regarding the impact of MP by defining dynamic networks of inflammation in both tissue and perfusate. Methods: Porcine liver allografts were preserved either with MP (n = 6 or with cold static preservation (CSP; n = 6, then transplanted orthotopically after 9 h of preservation. Fourteen inflammatory mediators were measured in both tissue and perfusate during liver preservation at multiple time points, and analyzed using Dynamic Bayesian Network (DyBN inference to define feedback interactions, as well as Dynamic Network Analysis (DyNA to define the time-dependent development of inflammation networks.Results: Network analyses of tissue and perfusate suggested an NLRP3 inflammasome-regulated response in both treatment groups, driven by the pro-inflammatory cytokine interleukin (IL-18 and the anti-inflammatory mediator IL-1 receptor antagonist (IL-1RA. Both DyBN and DyNA suggested a reduced role of IL-18 and increased role of IL-1RA with MP, along with increased liver damage with CSP. DyNA also suggested divergent progression of responses over the 9 h preservation time, with CSP leading to a stable pattern of IL-18-induced liver damage and MP leading to a resolution of the pro-inflammatory response. These results were consistent with prior clinical, biochemical, and histological findings after liver transplantation. Conclusion: Our results suggest that analysis of dynamic inflammation networks in the setting of liver preservation may identify novel

  10. Dynamic CT myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Caruso, Damiano; Eid, Marwen; Schoepf, U. Joseph; Jin, Kwang Nam; Varga-Szemes, Akos; Tesche, Christian; Mangold, Stefanie

    2016-01-01

    Highlights: • CT myocardial perfusion provides functional assessment of the myocardium. • CCTA is limited in determining the hemodynamic significance of coronary stenosis. • CT-MPI can accurately detect hemodynamically significant coronary artery stenosis. - Abstract: Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

  11. Dynamic CT myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Caruso, Damiano [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiological Sciences, Oncological and Pathological Sciences, University of Rome “Sapienza”, Latina (Italy); Eid, Marwen [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Schoepf, U. Joseph, E-mail: schoepf@musc.edu [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Division of Cardiology, Department of Medicine, Medical University of South Carolina, Charleston, SC (United States); Jin, Kwang Nam [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Radiology, Seoul Metropolitan Government-Seoul National University Boramae Medical Center, Seoul (Korea, Republic of); Varga-Szemes, Akos [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Tesche, Christian [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Cardiology and Intensive Care Medicine, Heart Center Munich-Bogenhausen, Munich (Germany); Mangold, Stefanie [Division of Cardiovascular Imaging, Department of Radiology and Radiological Science, Medical University of South Carolina, Charleston, SC (United States); Department of Diagnostic and Interventional Radiology, University Hospital of Tuebingen, Tuebingen (Germany); and others

    2016-10-15

    Highlights: • CT myocardial perfusion provides functional assessment of the myocardium. • CCTA is limited in determining the hemodynamic significance of coronary stenosis. • CT-MPI can accurately detect hemodynamically significant coronary artery stenosis. - Abstract: Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

  12. Lung perfusion scintigraphy by SPECT

    International Nuclear Information System (INIS)

    Hirayama, Takanobu

    1990-01-01

    The initial study reports the characteristic performance using lung segmental phantom filled in Tc-99m pertechnetate. To evaluate the segmental defect in lung perfusion scintigraphy, we applied Bull's-eye analysis in addition to planar image set. Bull's-eye analysis especially facilitated the interpretation in both middle and lower lobes. Subsequently, to evolute the clinical application of Bull's-eye analysis, pulmonary scintigraphy was performed on 10 normal subjects and 60 patients with several pulmonary diseases. Of interest, Bull's-eye analysis, however, encouraged the interpretation in both lower lobes. To calculate the extention and severity of perfusion defect, the present study describes Bull's-eye analysis. Quantitative scoring showed higher in patients with lung cancer than those with pulmonary tuberculosis. The present study focus that Bull's-eye analysis can be useful for evaluating perfusion in patients with a couple of pulmonary diseases. (author)

  13. Establishment of a hepatic cirrhosis and portal hypertension model by hepatic arterial perfusion with 80% alcohol.

    Science.gov (United States)

    Wang, Lei; He, Fu-Liang; Liu, Fu-Quan; Yue, Zhen-Dong; Zhao, Hong-Wei

    2015-08-28

    To determine the feasibility and safety of establishing a porcine hepatic cirrhosis and portal hypertension model by hepatic arterial perfusion with 80% alcohol. Twenty-one healthy Guizhou miniature pigs were randomly divided into three experimental groups and three control groups. The pigs in the three experimental groups were subjected to hepatic arterial perfusion with 7, 12 and 17 mL of 80% alcohol, respectively, while those in the three control groups underwent hepatic arterial perfusion with 7, 12 and 17 mL of saline, respectively. Hepatic arteriography and direct portal phlebography were performed on all animals before and after perfusion, and the portal venous pressure and diameter were measured before perfusion, immediately after perfusion, and at 2, 4 and 6 wk after perfusion. The following procedures were performed at different time points: routine blood sampling, blood biochemistry, blood coagulation and blood ammonia tests before surgery, and at 2, 4 and 6 wk after surgery; hepatic biopsy before surgery, within 6 h after surgery, and at 1, 2, 3, 4 and 5 wk after surgery; abdominal enhanced computed tomography examination before surgery and at 6 wk after surgery; autopsy and multi-point sampling of various liver lobes for histological examination at 6 wk after surgery. In experimental group 1, different degrees of hepatic fibrosis were observed, and one pig developed hepatic cirrhosis. In experimental group 2, there were cases of hepatic cirrhosis, different degrees of increased portal venous pressure, and intrahepatic portal venous bypass, but neither extrahepatic portal-systemic bypass circulation nor death occurred. In experimental group 3, two animals died and three animals developed hepatic cirrhosis, and different degrees of increased portal venous pressure and intrahepatic portal venous bypass were also observed, but there was no extrahepatic portal-systemic bypass circulation. It is feasible to establish an animal model of hepatic cirrhosis and

  14. CT perfusion imaging of the liver and the spleen in patients with cirrhosis: Is there a correlation between perfusion and portal venous hypertension?

    International Nuclear Information System (INIS)

    Talakic, Emina; Schoellnast, Helmut; Schaffellner, Silvia; Kniepeiss, Daniela; Mueller, Helmut; Stauber, Rudolf; Quehenberger, Franz

    2017-01-01

    To correlate hepatic and splenic CT perfusion parameters with hepatic venous pressure gradient (HVPG) measurements in patients with cirrhosis. Twenty-one patients with cirrhosis (males, 17; females, 4; mean ± SD age, 57 ± 7 years) underwent hepatic and splenic perfusion CT on a 320-detector row volume scanner as well as invasive measurement of HVPG. Different CT perfusion algorithms (maximum slope analysis and Patlak plot) were used to measure hepatic arterial flow (HAF), portal venous flow (PVF), hepatic perfusion index (HPI), splenic arterial flow (SAF), splenic blood volume (SBV) and splenic clearance (SCL). Hepatic and splenic perfusion parameters were correlated with HVPG, and sensitivity and specificity for detection of severe portal hypertension (≥12 mmHg) were calculated. The Spearman correlation coefficient was -0.53 (p < 0.05) between SAF and HVPG, and -0.68 (p < 0.01) between HVPG and SCL. Using a cut-off value of 125 ml/min/100 ml for SCL, sensitivity for detection of a HVPG of ≥12 mmHg was 94%, and specificity 100%. There was no significant correlation between hepatic perfusion parameters and HVPG. CT perfusion in patients with cirrhosis showed a strong correlation between SCL and HVPG and may be used for detection of severe portal hypertension. (orig.)

  15. CT perfusion imaging of the liver and the spleen in patients with cirrhosis: Is there a correlation between perfusion and portal venous hypertension?

    Energy Technology Data Exchange (ETDEWEB)

    Talakic, Emina; Schoellnast, Helmut [Medical University of Graz, Division of General Radiology, Department of Radiology, Graz (Austria); Schaffellner, Silvia; Kniepeiss, Daniela; Mueller, Helmut [Medical University of Graz, Department of Surgery, Division of Transplantation Surgery, Graz (Austria); Stauber, Rudolf [Medical University of Graz, Department of Internal Medicine, Division of Gastoenterology and Hepatology, Graz (Austria); Quehenberger, Franz [Medical University of Graz, Institute for Medical Informatics, Statistics and Documentation, Graz (Austria)

    2017-10-15

    To correlate hepatic and splenic CT perfusion parameters with hepatic venous pressure gradient (HVPG) measurements in patients with cirrhosis. Twenty-one patients with cirrhosis (males, 17; females, 4; mean ± SD age, 57 ± 7 years) underwent hepatic and splenic perfusion CT on a 320-detector row volume scanner as well as invasive measurement of HVPG. Different CT perfusion algorithms (maximum slope analysis and Patlak plot) were used to measure hepatic arterial flow (HAF), portal venous flow (PVF), hepatic perfusion index (HPI), splenic arterial flow (SAF), splenic blood volume (SBV) and splenic clearance (SCL). Hepatic and splenic perfusion parameters were correlated with HVPG, and sensitivity and specificity for detection of severe portal hypertension (≥12 mmHg) were calculated. The Spearman correlation coefficient was -0.53 (p < 0.05) between SAF and HVPG, and -0.68 (p < 0.01) between HVPG and SCL. Using a cut-off value of 125 ml/min/100 ml for SCL, sensitivity for detection of a HVPG of ≥12 mmHg was 94%, and specificity 100%. There was no significant correlation between hepatic perfusion parameters and HVPG. CT perfusion in patients with cirrhosis showed a strong correlation between SCL and HVPG and may be used for detection of severe portal hypertension. (orig.)

  16. Is Assessment of Femoral Head Perfusion During Modified Dunn for Unstable Slipped Capital Femoral Epiphysis an Accurate Indicator of Osteonecrosis?

    Science.gov (United States)

    Novais, Eduardo N; Sink, Ernest L; Kestel, Lauryn A; Carry, Patrick M; Abdo, João C M; Heare, Travis C

    2016-08-01

    The modified Dunn procedure, which is an open subcapital realignment through a surgical dislocation approach, has gained popularity for the treatment of unstable slipped capital femoral epiphysis (SCFE). Intraoperative monitoring of the femoral head perfusion has been recommended as a method of predicting osteonecrosis; however, the accuracy of this assessment has not been well documented. We asked (1) whether intraoperative assessment of femoral head perfusion would help identify hips at risk of developing osteonecrosis; (2) whether one of the four methods of assessment of femoral head perfusion is more accurate (highest area under the curve) at identifying hips at risk of osteonecrosis; and (3) whether specific clinical features would be associated with osteonecrosis occurrence after a modified Dunn procedure for unstable SCFE. Between 2007 and 2014, we performed 29 modified Dunn procedures for unstable SCFE (16 boys, 11 girls; median age, 13 years; range, 8-17 years); two were lost to followup before 1 year. During this period, six patients with unstable SCFE were treated by other procedures. All patients undergoing modified Dunn underwent assessment of epiphyseal perfusion by the presence of active bleeding and/or by intracranial pressure (ICP) monitoring. In the initial five patients perfusion was recorded once, either before dissection of the retinacular flap or after fixation by one of the two methods. In the remaining 22 patients (81%), perfusion was systematically assessed before dissection of the retinacular flap and after fixation by both methods. Minimum followup was 1 year (median, 2.5 years; range, 1-8 years) because osteonecrosis typically develops within the first year after surgery. Patients were assessed for osteonecrosis by the presence of femoral head collapse at radiographs obtained every 3 months during the first year after surgery. Seven (26%) of the 27 patients developed osteonecrosis. Measures of diagnostic accuracy including sensitivity

  17. Design modification and optimisation of the perfusion system of a tri-axial bioreactor for tissue engineering.

    Science.gov (United States)

    Hussein, Husnah; Williams, David J; Liu, Yang

    2015-07-01

    A systematic design of experiments (DOE) approach was used to optimize the perfusion process of a tri-axial bioreactor designed for translational tissue engineering exploiting mechanical stimuli and mechanotransduction. Four controllable design parameters affecting the perfusion process were identified in a cause-effect diagram as potential improvement opportunities. A screening process was used to separate out the factors that have the largest impact from the insignificant ones. DOE was employed to find the settings of the platen design, return tubing configuration and the elevation difference that minimise the load on the pump and variation in the perfusion process and improve the controllability of the perfusion pressures within the prescribed limits. DOE was very effective for gaining increased knowledge of the perfusion process and optimizing the process for improved functionality. It is hypothesized that the optimized perfusion system will result in improved biological performance and consistency.

  18. Characterizing potential heart agents with an isolated perfused heart system

    International Nuclear Information System (INIS)

    Pendleton, D.B.; Sands, H.; Gallagher, B.M.; Camin, L.L.

    1984-01-01

    The authors have used an isolated perfused heart system for characterizing potential myocardial perfusion radiopharamaceuticals. Rabbit or guinea pig (GP) hearts are removed and perfused through the aorta with a blood-free buffer. Heart rate and ventricular pressure are monitored as indices of viability. Tc-99m-MAA is 96-100% retained in these hearts, and Tc-99m human serum albumin shows less than 5% extraction. Tl-201 is 30-40% extracted. It is known that in-vivo, Tc-99m(dmpe)/sub 2/Cl/sub 2//sup +/ is taken up by rabbit heart but not by GP or human heart. Analogous results are obtained with the isolated perfused heart model, where the complex is extracted well by the isolated rabbit heart (24%) but not by the GP heart (<5%). Values are unchanged if human, rabbit or GP blood is mixed and co-injected with the complex. Tc-99m)dmpe)/sub 3//sup +/ is also taken up by rabbit but not by GP hearts in-vivo. However, isolated perfused hearts of both species extract this complex well (45-52%). Heart uptake is diminished to <7% if the complex is pre-equilibrated with human blood. GP blood produces a moderate inhibition (in GP hearts only) and rabbit blood has no effect. This suggests that a human or GP blood factor may have a significant effect on heart uptake of this complex. Tc-99m(CN-t-butyl)/sub 6//sup +/ is taken up well by both rabbit and GP hearts in-vivo, and is extracted 100% by both isolated perfused hearts. Heart retention remains high (73-75%) in the presence of human blood

  19. Associations between muscle perfusion and symptoms in knee osteoarthritis

    DEFF Research Database (Denmark)

    Bandak, E; Boesen, M; Bliddal, H

    2015-01-01

    -MRI and clinical data were analyzed in 94 patients. The typical participant was a woman with a mean age of 65 years, and a body mass index (BMI) of 32 kg/m(2). Reduced multiple regression models analyzing the association between KOOS and DCE-MRI perfusion variables of Total Muscle Volume showed a statistically...... significant association between Nvoxel% and KOOS pain (0.41 (SE 0.14); P = 0.0048). Nvoxel% was defined as the proportion of highly perfused voxels; i.e., the voxels that show an early and rapid increase on the signal intensity vs time curves, reach a plateau state (plateau pattern) and then showing...

  20. Dynamic CT myocardial perfusion imaging identifies early perfusion abnormalities in diabetes and hypertension : Insights from a multicenter registry

    NARCIS (Netherlands)

    Vliegenthart, Rozemarijn; De Cecco, Carlo N.; Wichmann, Julian L.; Meinel, Felix G.; Pelgrim, Gert Jan; Tesche, Christian; Ebersberger, Ullrich; Pugliese, Francesca; Bamberg, Fabian; Choe, Yeon Hyeon; Wang, Yining; Schoepf, U. Joseph

    2016-01-01

    Background: To identify patients with early signs of myocardial perfusion reduction, a reference base for perfusion measures is needed. Objective: To analyze perfusion parameters derived from dynamic computed tomography perfusion imaging (CTPI) in patients with suspected coronary artery disease

  1. Improved perfusion quantification in FAIR imaging by offset correction

    DEFF Research Database (Denmark)

    Sidaros, Karam; Andersen, Irene Klærke; Gesmar, Henrik

    2001-01-01

    Perfusion quantification using pulsed arterial spin labeling has been shown to be sensitive to the RF pulse slice profiles. Therefore, in Flow-sensitive Alternating-Inversion Recovery (FAIR) imaging the slice selective (ss) inversion slab is usually three to four times thicker than the imaging...... slice. However, this reduces perfusion sensitivity due to the increased transit delay of the incoming blood with unperturbed spins. In the present article, the dependence of the magnetization on the RF pulse slice profiles is inspected both theoretically and experimentally. A perfusion quantification...... model is presented that allows the use of thinner ss inversion slabs by taking into account the offset of RF slice profiles between ss and nonselective inversion slabs. This model was tested in both phantom and human studies. Magn Reson Med 46:193-197, 2001...

  2. Phase correction of MR perfusion/diffusion images

    International Nuclear Information System (INIS)

    Chenevert, T.L.; Pipe, J.G.; Brunberg, J.A.; Yeung, H.N.

    1989-01-01

    Apparent diffusion coefficient (ADC) and perfusion MR sequences are exceptionally sensitive to minute motion and, therefore, are prone to bulk motions that hamper ADC/perfusion quantification. The authors have developed a phase correction algorithm to substantially reduce this error. The algorithm uses a diffusion-insensitive data set to correct data that are diffusion sensitive but phase corrupt. An assumption of the algorithm is that bulk motion phase shifts are uniform in one dimension, although they may be arbitrarily large and variable from acquisition to acquisition. This is facilitated by orthogonal section selection. The correction is applied after one Fourier transform of a two-dimensional Fourier transform reconstruction. Imaging experiments on rat and human brain demonstrate significant artifact reduction in ADC and perfusion measurements

  3. Reduced density of the herbivorous urchin Diadema antillarum inside a Caribbean marine reserve linked to increased predation pressure by fishes

    Science.gov (United States)

    Harborne, A. R.; Renaud, P. G.; Tyler, E. H. M.; Mumby, P. J.

    2009-09-01

    Disease has dramatically reduced populations of the herbivorous urchin Diadema antillarum Philippi on Caribbean reefs, contributing to an increased abundance of macroalgae and reduction of coral cover. Therefore, recovery of D. antillarum populations is critically important, but densities are still low on many reefs. Among the many potential factors limiting these densities, the focus of this study is on predation pressure by fishes. Marine reserves provide opportunities to examine large-scale manipulations of predator-prey interactions and, therefore, D. antillarum densities were compared inside and outside a reserve in The Bahamas (Exuma Cays Land and Sea Park; ECLSP). Urchins and their fish predators were surveyed at nine sites inside and outside the ECLSP. Because of lower fishing effort, the total biomass of urchin predators, weighted by their dietary preferences for urchins, was significantly higher inside the ECLSP. Furthermore, fish community structure was significantly different inside the Park because of the increased biomass of the majority of species. No urchins were seen inside the ECLSP and this was significantly lower than the density of 0.04 urchin m-2 outside the Park. Regression analysis indicated that the relationship between the biomass of urchin predators and the proportion of transects containing urchins was non-linear, suggesting that small increases in fish biomass dramatically reduce urchin abundances. The link between lower density of urchins and higher density of their predators inside the ECLSP is strengthened by discounting five alternative primary mechanisms (variations in macroalgal cover, larval supply, environmental setting, density of other urchin species and abundance of predators not surveyed). Caribbean marine reserves have an important conservation role, but increased fish predation appears to reduce densities of D. antillarum. Urchins currently have limited functional significance on Bahamian reefs, but any future recovery of

  4. Local cooling reduces skin ischemia under surface pressure in rats: an assessment by wavelet analysis of laser Doppler blood flow oscillations

    International Nuclear Information System (INIS)

    Jan, Yih-Kuen; Liao, Fuyuan; Lee, Bernard; Foreman, Robert D

    2012-01-01

    The objectives of this study were to investigate the effects of local cooling on skin blood flow response to prolonged surface pressure and to identify associated physiological controls mediating these responses using the wavelet analysis of blood flow oscillations in rats. Twelve Sprague–Dawley rats were randomly assigned to three protocols, including pressure with local cooling (Δt = −10 °C), pressure with local heating (Δt = 10 °C) and pressure without temperature changes. Pressure of 700 mmHg was applied to the right trochanter area of rats for 3 h. Skin blood flow was measured using laser Doppler flowmetry. The 3 h loading period was divided into non-overlapping 30 min epochs for the analysis of the changes of skin blood flow oscillations using wavelet spectral analysis. The wavelet amplitudes and powers of three frequencies (metabolic, neurogenic and myogenic) of skin blood flow oscillations were calculated. The results showed that after an initial loading period of 30 min, skin blood flow continually decreased under the conditions of pressure with heating and of pressure without temperature changes, but maintained stable under the condition of pressure with cooling. Wavelet analysis revealed that stable skin blood flow under pressure with cooling was attributed to changes in the metabolic and myogenic frequencies. This study demonstrates that local cooling may be useful for reducing ischemia of weight-bearing soft tissues that prevents pressure ulcers. (paper)

  5. Acanthopanax divaricatus var. chiisanensis reduces blood pressure via the endothelial nitric oxide synthase pathway in the spontaneously hypertensive rat model.

    Science.gov (United States)

    Park, Soo-Yeon; Do, Gyeong-Min; Lee, Sena; Lim, Yeni; Shin, Jae-Ho; Kwon, Oran

    2014-09-01

    In this study, we investigated the antihypertensive effects of Acanthopanax divaricatus var. chiisanensis extract (AE) and its active compound, acanthoside D (AD), on arterial blood pressure (BP) in vivo and endothelial function in vitro. We hypothesized that AE has antihypertensive effects, which is attributed to enhancement of endothelial function via the improvement of nitric oxide synthesis or the angiotensin II (Ang II) response. Spontaneously hypertensive rats (SHRs) and Wistar-Kyoto rats (WKYs) were randomly divided into 7 groups and then fed the following diets for 14 weeks: WKY fed a normal diet (WN); SHR fed a normal diet (SN); SHR fed a high-cholesterol (HC) diet (SH); SHR fed a HC diet with AE of 150, 300, 600 mg/kg body weight (SH-L, SH-M, SH-H); and SHR fed an HC diet with AD of 600 μg/kg body weight (SH-D). Blood pressure was significantly reduced in the SH-H compared with the SH from week 10 until week 14; BP was also significantly decreased in the SHR fed a HC diet with AE of 300 at week 14. Aortic wall thickness showed a tendency to decrease by AE and AD treatment. The SH-H showed increased endothelial nitric oxide synthase (eNOS) expression in the intima and media, compared with the SH. Furthermore, a significant increase in intracellular nitric oxide production was induced by AE and AD treatment in human umbilical vein endothelial cells. A significant increase of phospho-eNOS was found with a high dose of AE in human umbilical vein endothelial cells but not with AD. These results suggest that AE can regulate BP and improve endothelial function via eNOS-dependent vasodilation. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Noninvasive study of extremity perfusion by 43K scanning

    International Nuclear Information System (INIS)

    Miyamoto, A.T.; Mishkin, F.S.; Maxwell, T.M.

    1975-01-01

    In nine patients with lower extremity symptoms of arterial insufficiency, potassium chloride 43 K was injected intravenously during rest, reactive hyperemia, or exercise. Decreased radioactivity in muscle tissue was observed to correspond with symptoms, physical findings, Doppler ultrasound pressures, and angiographic findings in all six who had the procedure. Studies following surgical endarterectomies in two, a bypass procedure in one, and exploration without attempted reconstruction in one showed good correlation with postoperative symptoms, physical findings, and pressure measurements using Doppler ultrasound in three of four patients. The fourth patient showed no change on the postoperative study despite clinical improvement. These findings suggest that intravenously administered radioactive potassium provides a noninvasive means for demonstrating the perfused muscle mass of the extremities with delineation of ischemic areas. The risk of arterial puncture is eliminated, and the ability to visualize perfusion patterns during exercise is unique to this method. (U.S.)

  7. Automatic assessment of cardiac perfusion MRI

    DEFF Research Database (Denmark)

    Ólafsdóttir, Hildur; Stegmann, Mikkel Bille; Larsson, Henrik B.W.

    2004-01-01

    In this paper, a method based on Active Appearance Models (AAM) is applied for automatic registration of myocardial perfusion MRI. A semi-quantitative perfusion assessment of the registered image sequences is presented. This includes the formation of perfusion maps for three parameters; maximum up...

  8. Electrical stimulation-induced Gluteal and Hamstring muscle activation can reduce sitting pressure in individuals with a spinal cord injury

    NARCIS (Netherlands)

    Janssen, T. W J; De Koning, A.; Legemate, K. J A; Smit, C. A J

    2010-01-01

    Individuals with spinal cord injury (SCI) are at high risk of developing pressure sores, in part due to high sitting pressures under the buttocks. PURPOSE: To evaluate the effect of ES-induced activation of the gluteal and hamstring muscles on the sitting pressure in individuals with SCI. METHODS:

  9. Control of substrate oxidation in MOD ceramic coating on low-activation ferritic steel with reduced-pressure atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Teruya, E-mail: teru@nifs.ac.jp; Muroga, Takeo

    2014-12-15

    Highlights: • A Cr{sub 2}O{sub 3} layer was produced on a ferritic steel substrate with a reduced-pressure. • The Cr{sub 2}O{sub 3} layer prevents further substrate oxidation in following coating process. • The Cr{sub 2}O{sub 3} layer has a function as a hydrogen permeation barrier. • A smooth MOD Er{sub 2}O{sub 3} coating was successfully made on the Cr{sub 2}O{sub 3} layer by dip coating. • The Cr{sub 2}O{sub 3} layer would enhance flexibility in MOD coating process and performances. - Abstract: An Er{sub 2}O{sub 3} ceramic coating fabricated using the metal–organic decomposition (MOD) method on a Cr{sub 2}O{sub 3}-covered low-activation ferritic steel JLF-1 substrate was examined to improve hydrogen permeation barrier performance of the coating. The Cr{sub 2}O{sub 3} layer was obtained before coating by heat treating the substrate at 700 °C under reduced pressures of <5 × 10{sup −3} Pa and 5 Pa. The Cr{sub 2}O{sub 3} layer was significantly stable even with heat treatment at 700 °C in air. This layer prevented further production of Fe{sub 2}O{sub 3}, which has been considered to degrade coating performance. An MOD Er{sub 2}O{sub 3} coating with a smooth surface was successfully obtained on a Cr{sub 2}O{sub 3}-covered JLF-1 substrate by dip coating followed by drying and baking. Preprocessing to obtain a Cr{sub 2}O{sub 3} layer would provide flexibility in the coating process for blanket components and ducts. Moreover, the Cr{sub 2}O{sub 3} layer suppressed hydrogen permeation through the JLF-1 substrate. While further optimization of the coating fabrication process is required, it would be possible to suppress hydrogen permeation significantly by multilayers of Cr{sub 2}O{sub 3} and MOD oxide ceramic.

  10. Pulmonary ventilation/perfusion scan

    Science.gov (United States)

    ... to stop eating (fast), be on a special diet, or take any medicines before the test. A chest x-ray is usually done before or after a ventilation and perfusion scan. You wear a hospital gown or comfortable clothing that does not have ...

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

    Science.gov (United States)

    Hauge, A; Nicolaysen, G

    1980-07-01

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

  12. Continuous positive airway pressure reduces blood pressure in patients with obstructive sleep apnea; a systematic review and meta-analysis with 1000 patients.

    Science.gov (United States)

    Schein, Andressa S O; Kerkhoff, Alessandra C; Coronel, Christian C; Plentz, Rodrigo D M; Sbruzzi, Graciele

    2014-09-01

    Obstructive sleep apnea (OSA) may lead to the development of hypertension and therapy with continuous positive airway pressure (CPAP) can promote reduction in blood pressure. The objective of this study is to review systematically the effects of CPAP on blood pressure in patients with OSA. The search was conducted in the following databases, from their beginning until February 2013: MEDLINE, Embase, Cochrane CENTRAL, Lilacs and PEDro. In addition, a manual search was performed on references of published studies. Randomized clinical trials (RCTs) that used CPAP compared with placebo CPAP or subtherapeutic CPAP for treatment of patients with OSA and that evaluated office SBP and DBP and 24-h ambulatory blood pressure were selected. Sixteen RCTs were included among 3409 publications, totaling 1166 patients. The use of CPAP resulted in reductions in office SBP [-3.20  mmHg; 95% confidence interval (CI) -4.67 to -1.72] and DBP (-2.87  mmHg; 95% CI -5.18 to -0.55); in night-time SBP (-4.92  mmHg; 95% CI -8.70 to -1.14); in mean 24-h blood pressure (-3.56  mmHg; 95% CI -6.79 to -0.33), mean night-time blood pressure (-2.56  mmHg; 95% CI -4.43 to -0.68) and 24-h DBP (-3.46  mmHg; 95% CI -6.75 to -0.17). However, no significant change was observed in daytime SBP (-0.74  mmHg; 95% CI -3.90 to 2.41) and daytime DBP (-1.86  mmHg; 95% CI -4.55 to 0.83). Treatment with CPAP promoted significantly but small reductions in blood pressure in individuals with OSA. Further studies should be performed to evaluate the effects of long-term CPAP and the impact on cardiovascular risk.

  13. Combination therapy with lercanidipine and enalapril reduced central blood pressure augmentation in hypertensive patients with metabolic syndrome.

    Science.gov (United States)

    Ghiadoni, Lorenzo; Bruno, Rosa Maria; Cartoni, Giulia; Stea, Francesco; Magagna, Armando; Virdis, Agostino; Grassi, Davide; Ferri, Claudio; Taddei, Stefano

    2017-05-01

    Arterial stiffness and blood pressure (BP) augmentation are independent predictors of cardiovascular events. In a randomized, open, parallel group study we compared the effect on these parameters of combination therapy with an ACE-inhibitor plus calcium channel blocker or thiazide diuretic in 76 hypertensive patients with metabolic syndrome uncontrolled by ACE-inhibitor monotherapy. After 4weeks run-in with enalapril (ENA, 20mg), patients were randomized to a combination therapy with lercanidipine (LER, 10-20mg) or hydrochlorothiazide (HCT, 12.5-25mg) for 24weeks. Aortic stiffness (carotid to femoral pulse wave velocity, PWV), central BP values and augmentation (augmentation index, AIx) were measured by applanation tonometry. The two groups showed similar office and central BP after run-in. Office (ENA/LER: from 149.1±4.9/94.5±1.5 to 131.7±8.1/82.2±5.3; ENA/HCT: from 150.3±4.7/94.7±2.1 to 133.1±7.1/82.8±5.3mmHg) and central BP (ENA/LER 127.4±17.1/85.2±12.1 to 120.5±13.5/80.0±9.5mmHg; ENA/HCT 121.6±13.4/79.3±9.5mmHg) were similarly reduced after 24weeks. PWV was comparable after run-in and not differently reduced by the two treatments (ENA/LER from 8.6±1.5 to 8.1±1.3m/s, pmetabolic syndrome not controlled by ENA alone. These results indicate a positive effect of the combination of ENA/LER on central BP augmentation, suggesting a potential additive role for cardiovascular protection. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. C and Si delta doping in Ge by CH_3SiH_3 using reduced pressure chemical vapor deposition

    International Nuclear Information System (INIS)

    Yamamoto, Yuji; Ueno, Naofumi; Sakuraba, Masao; Murota, Junichi; Mai, Andreas; Tillack, Bernd

    2016-01-01

    C and Si delta doping in Ge are investigated using a reduced pressure chemical vapor deposition system to establish atomic-order controlled processes. CH_3SiH_3 is exposed at 250 °C to 500 °C to a Ge on Si (100) substrate using H_2 or N_2 carrier gas followed by a Ge cap layer deposition. At 350 °C, C and Si are uniformly adsorbed on the Ge surface and the incorporated C and Si form steep delta profiles below detection limit of SIMS measurement. By using N_2 as carrier gas, the incorporated C and Si doses in Ge are saturated at one mono-layer below 350 °C. At this temperature range, the incorporated C and Si doses are nearly the same, indicating CH_3SiH_3 is adsorbed on the Ge surface without decomposing the C−Si bond. On the other hand, by using H_2 as carrier gas, lower incorporated C is observed in comparison to Si. CH_3SiH_3 injected with H_2 carrier gas is adsorbed on Ge without decomposing the C−Si bond and the adsorbed C is reduced by dissociation of the C−Si bond during temperature ramp up to 550 °C. The adsorbed C is maintained on the Ge surface in N_2 at 550 °C. - Highlights: • C and Si delta doping in Ge is investigated using RPCVD system by CH_3SiH_3 exposure. • Atomically flat C and Si delta layers are fabricated at 350 °C. • Incorporated C and Si doses are saturated at one mono-layer below 350 °C. • CH_3SiH_3 adsorption occurred without decomposing C−Si bond. • Adsorbed C is desorbed due to dissociation by hydrogen during postannealing at 550 °C.

  15. A Comprehensive Program to Reduce Rates of Hospital-Acquired Pressure Ulcers in a System of Community Hospitals.

    Science.gov (United States)

    Englebright, Jane; Westcott, Ruth; McManus, Kathryn; Kleja, Kacie; Helm, Colleen; Korwek, Kimberly M; Perlin, Jonathan B

    2018-03-01

    The prevention of hospital-acquired pressure ulcers (PrUs) has significant consequences for patient outcomes and the cost of care. Providers are challenged with evaluating available evidence and best practices, then implementing programs and motivating change in various facility environments. In a large system of community hospitals, the Reducing Hospital Acquired-PrUs Program was developed to provide a toolkit of best practices, timely and appropriate data for focusing efforts, and continuous implementation support. Baseline data on PrU rates helped focus efforts on the most vulnerable patients and care situations. Facilities were empowered to use and adapt available resources to meet local needs and to share best practices for implementation across the system. Outcomes were measured by the rate of hospital-acquired PrUs, as gathered from patient discharge records. The rate of hospital-acquired stage III and IV PrUs decreased 66.3% between 2011 and 2013. Of the 149 participating facilities, 40 (27%) had zero hospital-acquired stage III and IV PrUs and 77 (52%) had a reduction in their PrU rate. Rates of all PrUs documented as present on admission did not change during this period. A comparison of different strategies used by the most successful facilities illustrated the necessity of facility-level flexibility and recognition of local workflows and patient demographics. Driven by the combination of a repository of evidence-based tools and best practices, readily available data on PrU rates, and local flexibility with processes, the Reducing Hospital Acquired-PrUs Program represents the successful operationalization of improvement in a wide variety of facilities.

  16. Nasal continuous positive airway pressure therapy in a non-tertiary neonatal unit: reduced need for up-transfers.

    Science.gov (United States)

    Kiran, Sai; Murki, Srinivas; Pratap, Oleti Tejo; Kandraju, Hemasree; Reddy, Anupama

    2015-02-01

    To evaluate the need for up-transfer after starting of nasal continuous positive airway pressure (n-CPAP) services in a Level II special newborn care unit (SNCU). Five hundred fifty infants admitted to Level II SNCU, 252 infants during one year prior to introduction of n-CPAP (retrospective data from case records and electronic data base) and 298 infants during one year after introduction of n-CPAP services (prospective data in predefined case reporting form) were evaluated in this before and after intervention trial. The primary outcome was proportion of infants needing up-transfers from Level II SNCU for any indication. Baseline demographic data like birth weight, gestation and other perinatal factors were similar between the two epochs. Among the infants admitted to Level II SNCU, up-transfer for any reason was significantly higher in the pre-CPAP epoch compared with CPAP epoch (n = 93, 36 % vs. n = 74, 24.8 %, p = 0.002, OR 0.56, 95 % CI 0.38 to 0.83). However parent desired up-transfers were similar between the two epochs (n = 9, 3 % vs. n = 16, 5 %, p = 0.40). Introduction of n-CPAP treatment modality reduced up-transfers in subgroups of very low birth weight infants (VLBW) (n = 20, 74 % vs. n = 15, 37 %, p = 0.003) and also in preterm infants (n = 50, 54 % vs. n = 34, 32 %, p = 0.002). Introduction of n-CPAP services in a non-tertiary care neonatal unit, significantly reduced the need for up-transfers, especially in VLBW and preterm infants.

  17. Experimental study of the processes accompanying argon breakdown in a long discharge tube at a reduced pressure

    Energy Technology Data Exchange (ETDEWEB)

    Meshchanov, A. V.; Ionikh, Yu. Z., E-mail: y.ionikh@spbu.ru; Shishpanov, A. I.; Kalinin, S. A. [St. Petersburg State University (Russian Federation)

    2016-10-15

    Results are presented from experimental studies of the breakdown stage of a low-pressure discharge (1 and 5 Torr) in a glass tube the length of which (75 cm) is much larger than its diameter (2.8 cm). Breakdowns occurred under the action of positive voltage pulses with an amplitude of up to 9.4 kV and a characteristic rise time of 2–50 μs. The discharge current in the steady-state mode was 10–120 mA. The electrode voltage, discharge current, and radiation from the discharge gap were detected simultaneously. The dynamic breakdown voltage was measured, the prebreakdown ionization wave was recorded, and its velocity was determined. The dependence of the discharge parameters on the time interval between voltage pulses (the socalled “memory effect”) was analyzed. The memory effect manifests itself in a decrease or an increase in the breakdown voltage and a substantial decrease in its statistical scatter. The time interval between pulses in this case can reach 0.5 s. The effect of illumination of the discharge tube with a light source on the breakdown was studied. It is found that the irradiation of the anode region of the tube by radiation with wavelengths of ≤500 nm substantially reduces the dynamic breakdown voltage. Qualitative explanations of the obtained results are offered.

  18. Application of high pressure processing to reduce verotoxigenic E. coli in two types of dry-fermented sausage.

    Science.gov (United States)

    Omer, M K; Alvseike, O; Holck, A; Axelsson, L; Prieto, M; Skjerve, E; Heir, E

    2010-12-01

    The effect of high pressure processing (HPP) on the survival of verotoxigenic Escherichia coli (VTEC) in two types of Norwegian type dry-fermented sausages was studied. Two different types of recipes for each sausage type were produced. The sausage batter was inoculated with 6.8 log(10) CFU/g of VTEC O103:H25. After fermentation, drying and maturation, slices of finished sausages were vacuum packed and subjected to two treatment regimes of HPP. One group was treated at 600 MPa for 10 min and another at three cycles of 600 MPa for 200 s per cycle. A generalized linear model split by recipe type showed that these two HPP treatments on standard recipe sausages reduced E. coli by 2.9 log(10) CFU/g and 3.3 log(10) CFU/g, respectively. In the recipe with higher levels of dextrose, sodium chloride and sodium nitrite E. coli reduction was 2.7 log(10) CFU/g in both treatments. The data show that HPP has a potential to make the sausages safer and also that the effect depends somewhat on recipe. Copyright © 2010 The American Meat Science Association. Published by Elsevier Ltd. All rights reserved.

  19. Reduced-Pressure Chemical Vapor Deposition Growth of Isolated Ge Crystals and Suspended Layers on Micrometric Si Pillars.

    Science.gov (United States)

    Skibitzki, Oliver; Capellini, Giovanni; Yamamoto, Yuji; Zaumseil, Peter; Schubert, Markus Andreas; Schroeder, Thomas; Ballabio, Andrea; Bergamaschini, Roberto; Salvalaglio, Marco; Miglio, Leo; Montalenti, Francesco

    2016-10-05

    In this work, we demonstrate the growth of Ge crystals and suspended continuous layers on Si(001) substrates deeply patterned in high aspect-ratio pillars. The material deposition was carried out in a commercial reduced-pressure chemical vapor deposition reactor, thus extending the "vertical-heteroepitaxy" technique developed by using the peculiar low-energy plasma-enhanced chemical vapor deposition reactor, to widely available epitaxial tools. The growth process was thoroughly analyzed, from the formation of small initial seeds to the final coalescence into a continuous suspended layer, by means of scanning and transmission electron microscopy, X-ray diffraction, and μ-Raman spectroscopy. The preoxidation of the Si pillar sidewalls and the addition of hydrochloric gas in the reactants proved to be key to achieve highly selective Ge growth on the pillars top only, which, in turn, is needed to promote the formation of a continuous Ge layer. Thanks to continuum growth models, we were able to single out the different roles played by thermodynamics and kinetics in the deposition dynamics. We believe that our findings will open the way to the low-cost realization of tens of micrometers thick heteroepitaxial layer (e.g., Ge, SiC, and GaAs) on Si having high crystal quality.

  20. Hemodynamic study on liver cirrhosis: clinical application of CT perfusion imaging

    International Nuclear Information System (INIS)

    Jiang Li; Yang Jianyong; Xie Hongbo; Yang Xufeng; Yan Chaogui; Li Ziping; Zeng Fang

    2004-01-01

    Objective: To estimate hepatic perfusion parameters with helical CT, and to study the relationship between hepatic perfusion parameters and the severity of liver cirrhosis. Methods: Dynamic single-section computed tomography (CT) of the liver was performed in 40 participants, including 27 patients with liver cirrhosis and 13 patients without liver disease (control subjects). CT scans were obtained at a single level to include the liver, spleen, aorta, and portal vein. On each CT scan, the attenuation of these organs was measured in regions of interest to provide time-density curves. The arterial, portal venous, and total perfusion of the liver and the hepatic perfusion index were assessed. Results: In the control group, hepatic arterial perfusion, portal venous perfusion, and total hepatic perfusion were (0.2823 ± 0.0969) ml·min -1 ·ml -1 , (1.1788 ± 0.4004) ml·min -1 ·ml -1 , and (1.4563 ± 0.4439) ml·min -1 ·ml -1 , respectively. Hepatic perfusion index was (19.73 ±5.81)%. These hepatic perfusion parameters correlated significantly with the severity of liver cirrhosis. Hepatic arterial perfusion decreased in Child A and B cirrhotic patients [ (0.1685 ± 0.1068) ml·min -1 ·ml -1 and (0.1921 ± 0.0986) ml·min -1 ·ml -1 , respectively]. Comparing to Child A and B cirrhotic patients, hepatic arterial perfusion in Child C cirrhotic patients [(0.3072 · 0.1145) ml·min -1 ·ml -1 ] raised significantly. Portal venous perfusion decreased significantly in Child B and C cirrhotic patients [(0.6331±0.2070) ml·min -1 ·ml -1 and (0.5702 ± 0.3562) ml·min -1 ·ml -1 , respectively]. Total hepatic blood flow reduced markedly in Child B and C cirrhotic patients [(0.8252 ± 0.2952) ml·min -1 ·ml -1 and (0.8774 ± 0.4118) ml·min -1 ·ml -1 , respectively]. Hepatic perfusion index increased in Child C cirrhotic patients (37.48 ± 16.65)%. Conclusion: Dynamic single-section CT showed potential in quantifying hepatic perfusion parameters, and hepatic perfusion

  1. Contralateral thalamic hypoperfusion on brain perfusion SPECT

    International Nuclear Information System (INIS)

    Lee, Seok Mo; Bae, Sang Kyun; Yoo, Kyung Moo; Yum, Ha Yong

    2000-01-01

    Brain perfusion single photon emission computed tomography (SPECT) is useful for the localization of cerebrovascular lesion and sometimes reveals more definite lesion than radiologic imaging modality such as CT or MRI does. The purpose of this study was to evaluate the diagnostic usefulness of brain perfusion SPECT in patients with hemisensory impairment. Thirteen consecutive patients (M:F= 8:5, mean age = 48) who has hemisensory impairment were included. Brain perfusion SPECT was performed after intravenous injection of 1110 MBq of Tc-99m ECD. The images were obtained using a dual-head gamma camera with ultra-high resolution collimator. Semiquantitative analysis was performed after placing multiple ROIs on cerebral cortex, basal ganglia, thalamus and cerebellum. There were 10 patients with left hemisensory impairment and 3 patients with right-sided symptom. Only 2 patients revealed abnormal signal change in the thalamus on MRI. But brain perfusion SPECT showed decreased perfusion in the thalamus in 9 patients. Six patients among 10 patients with left hemisensory impairment revealed decreased perfusion in the contralateral thalamus on brain SPECT. The other 4 patients revealed no abnormality. Two patients among 3 patients with right hemisensory impairment also showed decreased perfusion in the contralateral thalamus on brain SPECT. One patients with right hemisensory impairment showed ipsilateral perfusion decrease. Two patients who had follow-up brain perfusion SEPCT after treatment revealed normalization of perfusion in the thalamus. Brain perfusion SPECT might be a useful tool in diagnosing patients with hemisensory impairment

  2. Magnetic resonance perfusion imaging without contrast media

    International Nuclear Information System (INIS)

    Martirosian, Petros; Graf, Hansjoerg; Schick, Fritz; Boss, Andreas; Schraml, Christina; Schwenzer, Nina F.; Claussen, Claus D.

    2010-01-01

    Principles of magnetic resonance imaging techniques providing perfusion-related contrast weighting without administration of contrast media are reported and analysed systematically. Especially common approaches to arterial spin labelling (ASL) perfusion imaging allowing quantitative assessment of specific perfusion rates are described in detail. The potential of ASL for perfusion imaging was tested in several types of tissue. After a systematic comparison of technical aspects of continuous and pulsed ASL techniques the standard kinetic model and tissue properties of influence to quantitative measurements of perfusion are reported. For the applications demonstrated in this paper a flow-sensitive alternating inversion recovery (FAIR) ASL perfusion preparation approach followed by true fast imaging with steady precession (true FISP) data recording was developed and implemented on whole-body scanners operating at 0.2, 1.5 and 3 T for quantitative perfusion measurement in various types of tissue. ASL imaging provides a non-invasive tool for assessment of tissue perfusion rates in vivo. Images recorded from kidney, lung, brain, salivary gland and thyroid gland provide a spatial resolution of a few millimetres and sufficient signal to noise ratio in perfusion maps after 2-5 min of examination time. Newly developed ASL techniques provide especially high image quality and quantitative perfusion maps in tissues with relatively high perfusion rates (as also present in many tumours). Averaging of acquisitions and image subtraction procedures are mandatory, leading to the necessity of synchronization of data recording to breathing in abdominal and thoracic organs. (orig.)

  3. Mediterranean diet reduces 24-hour ambulatory blood pressure, blood glucose, and lipids: one-year randomized, clinical trial.

    Science.gov (United States)

    Doménech, Mónica; Roman, Pilar; Lapetra, José; García de la Corte, Francisco J; Sala-Vila, Aleix; de la Torre, Rafael; Corella, Dolores; Salas-Salvadó, Jordi; Ruiz-Gutiérrez, Valentina; Lamuela-Raventós, Rosa-María; Toledo, Estefania; Estruch, Ramón; Coca, Antonio; Ros, Emilio

    2014-07-01

    The PREvención con DIeta MEDiterránea (PREDIMED) trial showed that Mediterranean diets (MedDiets) supplemented with either extravirgin olive oil or nuts reduced cardiovascular events, particularly stroke, compared with a control, lower fat diet. The mechanisms of cardiovascular protection remain unclear. We evaluated the 1-year effects of supplemented MedDiets on 24-hour ambulatory blood pressure (BP), blood glucose, and lipids. Randomized, parallel-design, controlled trial was conducted in 2 PREDIMED sites. Diets were ad libitum, and no advice on increasing physical activity or reducing sodium intake was given. Participants were 235 subjects (56.5% women; mean age, 66.5 years) at high cardiovascular risk (85.4% with hypertension). Adjusted changes from baseline in mean systolic BP were -2.3 (95% confidence interval [CI], -4.0 to -0.5) mm Hg and -2.6 (95% CI, -4.3 to -0.9) mm Hg in the MedDiets with olive oil and the MedDiets with nuts, respectively, and 1.7 (95% CI, -0.1 to 3.5) mm Hg in the control group (P<0.001). Respective changes in mean diastolic BP were -1.2 (95% CI, -2.2 to -0.2), -1.2 (95% CI, -2.2 to -0.2), and 0.7 (95% CI, -0.4 to 1.7) mm Hg (P=0.017). Daytime and nighttime BP followed similar patterns. Mean changes from baseline in fasting blood glucose were -6.1, -4.6, and 3.5 mg/dL (P=0.016) in the MedDiets with olive oil, MedDiets with nuts, and control diet, respectively; those of total cholesterol were -11.3, -13.6, and -4.4 mg/dL (P=0.043), respectively. In high-risk individuals, most with treated hypertension, MedDiets supplemented with extravirgin olive oil or nuts reduced 24-hour ambulatory BP, total cholesterol, and fasting glucose. http://www.clinicaltrials.gov. Unique identifier: ISRCTN35739639. © 2014 American Heart Association, Inc.

  4. Sleep Apnea Related Risk of Motor Vehicle Accidents is Reduced by Continuous Positive Airway Pressure: Swedish Traffic Accident Registry Data

    Science.gov (United States)

    Karimi, Mahssa; Hedner, Jan; Häbel, Henrike; Nerman, Olle; Grote, Ludger

    2015-01-01

    Study Objectives: Obstructive sleep apnea (OSA) is associated with an increased risk of motor vehicle accidents (MVAs). The rate of MVAs in patients suspected of having OSA was determined and the effect of continuous positive airway pressure (CPAP) was investigated. Design: MVA rate in patients referred for OSA was compared to the rate in the general population using data from the Swedish Traffic Accident Registry (STRADA), stratified for age and calendar year. The risk factors for MVAs, using demographic and polygraphy data, and MVA rate before and after CPAP were evaluated in the patient group. Setting: Clinical sleep laboratory and population based control (n = 635,786). Patients: There were 1,478 patients, male sex 70.4%, mean age 53.6 (12.8) y. Interventions: CPAP. Measurements and Results: The number of accidents (n = 74) among patients was compared with the expected number (n = 30) from a control population (STRADA). An increased MVA risk ratio of 2.45 was found among patients compared with controls (P accident risk was most prominent in the elderly patients (65–80 y, seven versus two MVAs). In patients, driving distance (km/y), EDS (Epworth Sleepiness score ≥ 16), short habitual sleep time (≤ 5 h/night), and use of hypnotics were associated with increased MVA risk (odds ratios 1.2, 2.1, 2.7 and 2.1, all P ≤ 0.03). CPAP use ≥ 4 h/night was associated with a reduction of MVA incidence (7.6 to 2.5 accidents/1,000 drivers/y). Conclusions: The motor vehicle accident risk in this large cohort of unselected patients with obstructive sleep apnea suggests a need for accurate tools to identify individuals at risk. Sleep apnea severity (e.g., apnea-hypopnea index) failed to identify patients at risk. Citation: Karimi M, Hedner J, Häbel H, Nerman O, Grote L. Sleep apnea related risk of motor vehicle accidents is reduced by continuous positive airway pressure: Swedish traffic accident registry data. SLEEP 2015;38(3):341–349. PMID:25325460

  5. Comparing kidney perfusion using noncontrast arterial spin labeling MRI and microsphere methods in an interventional swine model.

    Science.gov (United States)

    Artz, Nathan S; Wentland, Andrew L; Sadowski, Elizabeth A; Djamali, Arjang; Grist, Thomas M; Seo, Songwon; Fain, Sean B

    2011-02-01

    The purpose of this study was to assess the ability of a flow-sensitive alternating inversion recovery-arterial spin labeling (FAIR-ASL) technique to track renal perfusion changes during pharmacologic and physiologic alterations in renal blood flow using microspheres as a gold standard. Fluorescent microsphere and FAIR-ASL perfusion were compared in the cortex of the kidney for 11 swine across 4 interventional time points: (1) under baseline conditions, (2) during an acetylcholine and fluid bolus challenge to increase perfusion, (3) initially after switching to isoflurane anesthesia, and (4) after 2 hours of isoflurane anesthesia. In 10 of the 11 swine, a bag of ice was placed on the hilum of 1 kidney at the beginning of isoflurane administration to further reduce perfusion in 1 kidney. Both ASL and microspheres tracked the expected cortical perfusion changes (P values were systematically lower compared with microsphere perfusion. Very good correlation (r = 0.81, P values in the expected physiologic range (microsphere perfusion values saturated for perfusion >550 mL/min/100 g. Cortical perfusion measured with ASL correlated with microspheres and reliably detected changes in renal perfusion in response to physiologic challenge.

  6. Prognostic value of myocardial perfusion SPECT imaging in elderly patients without history of coronary artery disease and low prevalence of them

    International Nuclear Information System (INIS)

    Arja, V.J.; Balestrini, V.R.; Sandrin, A.L.; Conci, E.C.; Serra, C.M.; Joekes, S.

    2002-01-01

    Elderly patients without history of coronary artery disease are difficult to characterized because the clinical symptoms are often atypical, occult or absent. On the other hand, these patients frequently cannot achieve adequate level of exercise during stress testing and this limitation can compromise the diagnostic and prognostic ability of the test. Generally the prognostic value of myocardial perfusion SPECT is well established for a general population but not for elderly patients. Aim: This study assessed the prognostic value of Tc99m-sestamibi SPECT in a group of patients older than 65 years with low prevalence of coronary artery disease. Material and Methods: Population: 161 consecutive patients older than 65 years without history of coronary artery disease and low prevalence of them were studied with Tc99m-sestamibi SPECT perfusion imaging. Mean age 71 years old (65-87), male 55%, mean pretest likelihood 11%. Risk factors: diabetes 17%, high blood pressure 74%, high cholesterol 45%, smokers 88%. Stress test: bicycle exercise 39% and dipyridamole 61%. Myocardial perfusion SPECT: semiquantitative analysis to evaluate perfusion defects with a 14-segments model and 4-point scoring system for uptake reduction. Scintigraphic indices: SSS (sum of the stress scores), SRS (sum of the rest scores) and SDS (SSS-SRS). Follow up: cardiac events: hard (acute myocardial infarction and cardiac death) and soft (need for PTCA/CABG and angina). Results: Mean follow up: 508 days. Events rate: hard 0.6% (1 acute myocardial infarction), soft 5.6%. Univariate analysis identified sex (p=0.017) and SDS (p=0.009) as cardiac events predictors. Complete or reduced (independent variables which predicted events) logistic regression analysis correctly predicted the absence of events but did not predict the presence of events. Conclusion: In this elderly population with a low clinical risk where the stress test is a suboptimal method of study for coronary artery disease, semiquantitative

  7. Correlation of the perfusion scintigram with pulmonary functions in chronic obstructive pulmonary disease

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Kou; Ashitaka, Tsuyoshi; Uchibori, Shigeyasu [Toho Univ., Tokyo (Japan). School of Medicine; Takano, Masaaki

    1992-11-01

    The authors carried out ventilation-perfusion scintigraphy and pulmonary function tests in 21 patients with chronic obstructive pulmonary disease. It was used [sup 99m]Tc-macroaggregate for perfusion scintigram and [sup 133]Xe gas for ventilation scintigram. It was added the radioactivities of rebreathing phase and made lung volume image using a computer. Regions of interest (ROIs) were derived from radioactivities in each image. ROIs on lung volume image included each whole lung and those on perfusion image included the areas which had relatively high radioactivity. The authors counted the area of ROIs on lung volume (L) and perfusion (P) images. Then it was used the ratio of perfusion to lung volume (P/L) as a parameter of pulmonary perfusion. P/L had the significant correlations with the vital capacity, the actual FFV[sub 1.0], arterial oxygen partial pressure, diffusing capacity, RV/TLC and peak flow rate. These results suggested that P/L was a useful parameter of pulmonary perfusion in chronic obstructive pulmonary disease. (author).

  8. Combined exercise reduces arterial stiffness, blood pressure, and blood markers for cardiovascular risk in postmenopausal women with hypertension.

    Science.gov (United States)

    Son, Won-Mok; Sung, Ki-Dong; Cho, Jae-Min; Park, Song-Young

    2017-03-01

    Postmenopausal women exhibit elevated brachial-ankle pulse wave velocity (baPWV), an indicator of arterial stiffness, which is associated with an increased risk of cardiovascular events and mortality. The purpose of this study is to examine the impact of combined resistance and aerobic exercise training on baPWV, blood pressure (BP), and cardiovascular fitness in postmenopausal women with stage 1 hypertension. Twenty postmenopausal women (age, 75 ± 2 y; systolic BP, 152 ± 2 mm Hg, diastolic BP, 95 ± 3 mm Hg) were randomly assigned to a "no-exercise" (CON, n = 10) or combined exercise (EX, n = 10) group. The EX group performed resistance and aerobic exercise for 12 weeks, 3 times per week. Exercise intensity was increased gradually, from 40% to 70% of heart rate reserve, every 4 weeks. BaPWV, BP, blood nitrite/nitrate, endothelin-1 (ET-1), cardiovascular fitness, and body composition were measured before and after the 12-week intervention. BP, baPWV (-1.2 ± 0.4 m/s), ET-1 (-2.7 ± 0.3 μmol/mL), nitrite/nitrate (+4.5 ± 0.5 μM), functional capacity, and body composition were significantly improved (P exercise training improves arterial stiffness, BP, ET-1, blood nitrite/nitrate, functional capacity, and body composition in postmenopausal women with stage 1 hypertension. Thus, this study provides evidence that combined exercise training is a useful therapeutic method to improve cardiovascular health which can reduce cardiovascular disease risk in postmenopausal women with hypertension.

  9. Dermal application of nitric oxide releasing acidified nitrite-containing liniments significantly reduces blood pressure in humans.

    Science.gov (United States)

    Opländer, Christian; Volkmar, Christine M; Paunel-Görgülü, Adnana; Fritsch, Thomas; van Faassen, Ernst E; Mürtz, Manfred; Grieb, Gerrit; Bozkurt, Ahmet; Hemmrich, Karsten; Windolf, Joachim; Suschek, Christoph V

    2012-02-15

    Vascular ischemic diseases, hypertension, and other systemic hemodynamic and vascular disorders may be the result of impaired bioavailability of nitric oxide (NO). NO but also its active derivates like nitrite or nitroso compounds are important effector and signal molecules with vasodilating properties. Our previous findings point to a therapeutical potential of cutaneous administration of NO in the treatment of systemic hemodynamic disorders. Unfortunately, no reliable data are available on the mechanisms, kinetics and biological responses of dermal application of nitric oxide in humans in vivo. The aim of the study was to close this gap and to explore the therapeutical potential of dermal nitric oxide application. We characterized with human skin in vitro and in vivo the capacity of NO, applied in a NO-releasing acidified form of nitrite-containing liniments, to penetrate the epidermis and to influence local as well as systemic hemodynamic parameters. We found that dermal application of NO led to a very rapid and significant transepidermal translocation of NO into the underlying tissue. Depending on the size of treated skin area, this translocation manifests itself through a significant systemic increase of the NO derivates nitrite and nitroso compounds, respectively. In parallel, this translocation was accompanied by an increased systemic vasodilatation and blood flow as well as reduced blood pressure. We here give evidence that in humans dermal application of NO has a therapeutic potential for systemic hemodynamic disorders that might arise from local or systemic insufficient availability of NO or its bio-active NO derivates, respectively. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. High-Pressure-High-Temperature Processing Reduces Maillard Reaction and Viscosity in Whey Protein-Sugar Solutions

    NARCIS (Netherlands)

    Avila Ruiz, Geraldine; Xi, Bingyan; Minor, Marcel; Sala, Guido; Boekel, van Tiny; Fogliano, Vincenzo; Stieger, Markus

    2016-01-01

    The aim of the study was to determine the influence of pressure in high-pressure-high-temperature (HPHT) processing on Maillard reactions and protein aggregation of whey protein-sugar solutions. Solutions of whey protein isolate containing either glucose or trehalose at pH 6, 7, and 9 were

  11. Leukocytic Toll-Like Receptor 2 Deficiency Preserves Cardiac Function And Reduces Fibrosis In Sustained Pressure Overload

    NARCIS (Netherlands)

    Wang, Jiong-Wei; Fontes, Magda S. C.; Wang, Xiaoyuan; Chong, Suet Yen; Kessler, Elise L.; Zhang, Ya-Nan; de Haan, Judith J.; Arslan, Fatih; de Jager, Saskia C. A.; Timmers, Leo; van Veen, Toon A. B.; Lam, Carolyn S. P.; de Kleijn, Dominique P. V.

    2017-01-01

    An involement of Toll-like receptor 2 (TLR2) has been established in cardiac dysfunction after acute myocardial infarction; however, its role in chronic pressure overload is unclear. We sought to evaluate the role of TLR2 in cardiac hypertrophy, fibrosis and dysfunction in sustained pressure

  12. Acetylcysteine reduces plasma homocysteine concentration and improves pulse pressure and endothelial function in patients with end-stage renal failure

    DEFF Research Database (Denmark)

    Scholze, Alexandra; Rinder, Christiane; Beige, Joachim

    2004-01-01

    Increased oxidative stress, elevated plasma homocysteine concentration, increased pulse pressure, and impaired endothelial function constitute risk factors for increased mortality in patients with end-stage renal failure.......Increased oxidative stress, elevated plasma homocysteine concentration, increased pulse pressure, and impaired endothelial function constitute risk factors for increased mortality in patients with end-stage renal failure....

  13. A quantitative analysis of microcirculation in sore-prone pressure areas on conventional and pressure relief hospital mattresses using laser Doppler flowmetry and tissue spectrophotometry.

    Science.gov (United States)

    Rothenberger, Jens; Krauss, Sabrina; Held, Manuel; Bender, Dominik; Schaller, Hans-Eberhard; Rahmanian-Schwarz, Afshin; Constantinescu, Mihai Adrian; Jaminet, Patrick

    2014-11-01

    Pressure ulcers are associated with severe impairment for the patients and high economic load. With this study we wanted to gain more insight to the skin perfusion dynamics due to external loading. Furthermore, we evaluated the effect of different types of pressure relief mattresses. A total of 25 healthy volunteers were enrolled in the study. Perfusion dynamics of the sacral and the heel area were assessed using the O2C-device, which combines a laser light, to determine blood flow, and white light to determine the relative amount of hemoglobin. Three mattresses were evaluated compared to a hard surface: a standard hospital foam mattress bed, a visco-elastic foam mattress, and an air-fluidized bed. In the heel area, only the air-fluidized bed was able to maintain the blood circulation (mean blood flow of 13.6 ± 6 versus 3.9 ± 3 AU and mean relative amount of hemoglobin of 44.0 ± 14 versus 32.7 ± 12 AU.) In the sacral area, all used mattresses revealed an improvement of blood circulation compared to the hard surface. The results of this study form a more precise pattern of perfusion changes due to external loading on various pressure relief mattresses. This knowledge may reduce the incidence of pressure ulcers and may be an influencing factor in pressure relief mattress selection. Copyright © 2014 Tissue Viability Society. Published by Elsevier Ltd. All rights reserved.

  14. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

    Larsson, H B; Fritz-Hansen, T; Rostrup, Egill

    1996-01-01

    In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...... turbo-FLASH (fast low-angle shot) sequence and Gd-DTPA has been presented. Here, an extension of the model is presented taking into account fast and slow water exchange between the compartments, enabling the calculation of the unidirectional influx constant (Ki) for Gd-DTPA, the distribution volume...... of Gd-DTPA (lambda), the vascular blood volume (Vb), and the time delay through the coronary arteries (delta T). The model was evaluated by computer simulation and used on experimental results from seven healthy subjects. The results in the healthy volunteers for a region of interest placed...

  15. Cholecalciferol treatment to reduce blood pressure in older patients with isolated systolic hypertension: the VitDISH randomized controlled trial.

    Science.gov (United States)

    Witham, Miles D; Price, Rosemary J G; Struthers, Allan D; Donnan, Peter T; Messow, Claudia-Martina; Ford, Ian; McMurdo, Marion E T

    2013-10-14

    Observational data link low 25-hydroxyvitamin D levels to both prevalent blood pressure and incident hypertension. No clinical trial has yet examined the effect of vitamin D supplementation in isolated systolic hypertension, the most common pattern of hypertension in older people. To test whether high-dose, intermittent cholecalciferol supplementation lowers blood pressure in older patients with isolated systolic hypertension. Parallel group, double-blind, placebo-controlled randomized trial. Primary care clinics and hospital clinics. Patients 70 years and older with isolated systolic hypertension (supine systolic blood pressure >140 mm Hg and supine diastolic blood pressure blood pressure, 24-hour blood pressure, arterial stiffness, endothelial function, cholesterol level, insulin resistance, and b-type natriuretic peptide level during 12 months. A total of 159 participants were randomized (mean age, 77 years). Mean baseline office systolic blood pressure was 163/78 mm Hg. Mean baseline 25-hydroxyvitamin D level was 18 ng/mL. 25-Hydroxyvitamin D levels increased in the treatment group compared with the placebo group (+8 ng/mL at 1 year, P blood pressure (−1 [−6 to 4]/−2 [−4 to 1] mm Hg at 3 months and 1 [−2 to 4]/0 [−2 to 2] mm Hg overall treatment effect). No significant treatment effect was evident for any of the secondary outcomes (24-hour blood pressure, arterial stiffness, endothelial function, cholesterol level, glucose level, and walking distance). There was no excess of adverse events in the treatment group, and the total number of falls was nonsignificantly lower in the group receiving vitamin D (36 vs 46, P = .24). Vitamin D supplementation did not improve blood pressure or markers of vascular health in older patients with isolated systolic hypertension. isrctn.org Identifier: ISRCTN92186858.

  16. Dosimetry in myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Toledo, Janine M.; Trindade, Bruno; Ribeiro, Tarcisio P.C. [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte (Brazil). Dept. de Engenharia Nuclear. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares

    2011-07-01

    This paper conducts a dosimetric investigation on the myocardial perfusion image protocol, together with a literature reviewing, motivated by the significant statistic increasing on mortality, morbidity and disability associated with cardiovascular disease, surpassing infectious diseases. Nuclear Cardiology plays a role n the diagnostic functional evaluation of the heart and in the prognostic of patients with suspected or known cardiac ischemia. In the context of unstable myocardial ischemic syndrome, myocardial perfusion scintigraphy is a non-invasive procedure performed by administering a radiopharmaceutical targeted to the heart. As tool for this study are that the images obtained by thoracic angiotomography and abdominal aorta as a anatomic and functional information for model reproduction in SISCODES - System of Codes for Absorbed Dose Calculations based on Stochastic Methods. Data were manipulated in order to create a voxel computational model of the heart to be running in MCNP - Monte Carlo Neutron Particle Code. . It was assumed a homogeneous distribution of Tl-201 in cardiac muscle. Simulations of the transport of particles through the voxel and the interaction with the heart tissue were performed. As a result, the isodose curves in the heart model are displayed as well as the dose versus volume histogram of the heart muscle. We conclude that the present computational tools can generate doses distributed in myocardial perfusion. (author)

  17. Dosimetry in myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Toledo, Janine M.; Trindade, Bruno; Ribeiro, Tarcisio P.C.

    2011-01-01

    This paper conducts a dosimetric investigation on the myocardial perfusion image protocol, together with a literature reviewing, motivated by the significant statistic increasing on mortality, morbidity and disability associated with cardiovascular disease, surpassing infectious diseases. Nuclear Cardiology plays a role n the diagnostic functional evaluation of the heart and in the prognostic of patients with suspected or known cardiac ischemia. In the context of unstable myocardial ischemic syndrome, myocardial perfusion scintigraphy is a non-invasive procedure performed by administering a radiopharmaceutical targeted to the heart. As tool for this study are that the images obtained by thoracic angiotomography and abdominal aorta as a anatomic and functional information for model reproduction in SISCODES - System of Codes for Absorbed Dose Calculations based on Stochastic Methods. Data were manipulated in order to create a voxel computational model of the heart to be running in MCNP - Monte Carlo Neutron Particle Code. . It was assumed a homogeneous distribution of Tl-201 in cardiac muscle. Simulations of the transport of particles through the voxel and the interaction with the heart tissue were performed. As a result, the isodose curves in the heart model are displayed as well as the dose versus volume histogram of the heart muscle. We conclude that the present computational tools can generate doses distributed in myocardial perfusion. (author)

  18. Physiologic Pressure and Flow Changes During Parabolic Flight (Pilot Study)

    Science.gov (United States)

    Pantalos, George; Sharp, M. Keith; Mathias, John R.; Hargens, Alan R.; Watenpaugh, Donald E.; Buckey, Jay C.

    1999-01-01

    The objective of this study was to obtain measurement of cutaneous tissue perfusion central and peripheral venous pressure, and esophageal and abdominal pressure in human test subjects during parabolic flight. Hemodynamic data recorded during SLS-I and SLS-2 missions have resulted in the paradoxical finding of increased cardiac stroke volume in the presence of a decreased central venous pressure (CVP) following entry in weightlessness. The investigators have proposed that in the absence of gravity, acceleration-induced peripheral vascular compression is relieved, increasing peripheral vascular capacity and flow while reducing central and peripheral venous pressure, This pilot study seeks to measure blood pressure and flow in human test subjects during parabolic flight for different postures.

  19. Ventilation and ventilation/perfusion ratios

    International Nuclear Information System (INIS)

    Valind, S.O.

    1989-01-01

    The thesis is based on five different papers. The labelling of specific tracer compounds with positron emitting radionuclides enables a range of structural, physiological and biochemical parameters in the lung to be measured non-invasively, using positron emission tomography. This concept affords a unique opportunity for in vivo studies of different expressions of pulmonary pathophysiology at the regional level. The present thesis describes the application of positron emission tomography to the measurements of ventilation and ventilation/perfusion ratios using inert gas tracers, neon-19 and nitrogen-13 respectively. The validity of the methods applied was investigated with respect to the transport of inert gas tracers in the human lung. Both ventilation and the ventilation/perfusion ratio may be obtained with errors less than 10 % in the normal lung. In disease, however, errors may increase in those instances where the regional ventilation is very low or the intra-regional gas flow distribution is markedly nonuniform. A 2-3 fold increase in ventilation was demonstrated in normal nonsmoking subjects going from ventral to dorsal regions in the supine posture. These large regional differences could be well explained by the intrinsic elastic properties of lung tissue, considering the gravitational gradient in transpulmonary pressure. In asymptomatic smokers substantial regional ventilatroy abnormalities were found whilst the regional gas volume was similar in smokers and nonsmokers. The uncoupling between ventilation and gas volume probably reflects inflammatory changes in the airways. The regional differences in dV/dt/dQ/dt were relatively small and blood flow was largely matched to ventilation in the supine posture. However, small regions of lung with very low ventilation, unmatched by blood flow commonly exists in the most dependent parts of the lung in both smokers and nonsmokers. (29 illustrations, 7 tables, 113 references)

  20. Efficacy of a brief multifactorial adherence-based intervention on reducing the blood pressure of patients with poor adherence: protocol for a randomized clinical trial

    Directory of Open Access Journals (Sweden)

    Llobera Joan

    2010-09-01

    Full Text Available Abstract Background Lowering of blood pressure by antihypertensive drugs reduces the risks of cardiovascular events, stroke, and total mortality. However, poor adherence to antihypertensive medications reduces their effectiveness and increases the risk of adverse events. In terms of relative risk reduction, an improvement in medication adherence could be as effective as the development of a new drug. Methods/Design The proposed randomized controlled trial will include patients with a low adherence to medication and uncontrolled blood pressure. The intervention group will receive a multifactorial intervention during the first, third, and ninth months, to improve adherence. This intervention will include motivational interviews, pill reminders, family support, blood pressure self-recording, and simplification of the dosing regimen. Measurement The primary outcome is systolic blood pressure. The secondary outcomes are diastolic blood pressure, proportion of patients with adequately controlled blood pressure, and total cost. Discussion The trial will evaluate the impact of a multifactorial adherence intervention in routine clinical practice. Ethical approval was given by the Ethical Committee on Human Research of Balearic islands, Spain (approval number IB 969/08 PI. Trial registration Current controlled trials ISRCTN21229328

  1. Integrating a hip belt with body armour reduces the magnitude and changes the location of shoulder pressure and perceived discomfort in soldiers.

    Science.gov (United States)

    Lenton, Gavin K; Doyle, Tim L A; Saxby, David J; Billing, Dan; Higgs, Jeremy; Lloyd, David G

    2018-04-01

    Soldiers carry heavy loads that may cause general discomfort, shoulder pain and injury. This study assessed if new body armour designs that incorporated a hip belt reduced shoulder pressures and improved comfort. Twenty-one Australian soldiers completed treadmill walking trials wearing six different body armours with two different loads (15 and 30 kg). Contact pressures applied to the shoulders were measured using pressure pads, and qualitative assessment of comfort and usability were acquired from questionnaires administered after walking trials. Walking with hip belt compared to no hip belt armour resulted in decreased mean and maximum shoulder pressures (p armour and backpack designs should integrate a hip belt and distribute load closer to shoulder midline to reduce load carriage discomfort and, potentially, injury risk. Practitioner Summary: Soldiers carry heavy loads that increase their risk of discomfort and injury. New body armour designs are thought to ease this burden by transferring the load to the hips. This study demonstrated that designs incorporating a hip belt reduced shoulder pressure and shoulder discomfort compared to the current armour design.

  2. Normothermic extracorporeal perfusion of isolated porcine liver after warm ischaemia: a preliminary report.

    Science.gov (United States)

    Bellomo, Rinaldo; Suzuki, Satoshi; Marino, Bruno; Starkey, Graeme K; Chambers, Brenton; Fink, Michael A; Wang, Bao Zhong; Houston, Shane; Eastwood, Glenn; Calzavacca, Paolo; Glassford, Neil; Skene, Alison; Jones, Daryl A; Jones, Robert

    2012-09-01

    Liver transplantation is a major life-saving procedure, and donation after cardiac death (DCD) has increased the pool of potential liver donors. However, DCD livers are at increased risk of primary graft dysfunction and biliary tract ischaemia. Normothermic extracorporeal liver perfusion (NELP) may increase the ability to protect, evaluate and, in future, transplant DCD livers. We conducted proof-of-concept experiments using a DCD model in the pig to assess the short-term (4 hours) feasibility and functional efficacy of NELP. Using extracorporeal membrane oxygenation, parenteral nutrition, separate hepatic artery and portal vein perfusion, and physiological perfusion pressures, we achieved NELP and evidence of function (bile production, paracetamol removal, maintenance of normal ammonia and lactate levels) for 4 hours in pig livers subjected to 15 and 30 minutes of cardiac arrest before explantation. Our experiments justify further investigations of the feasibility and efficacy of human DCD liver preservation by ex-vivo perfusion.

  3. Extended normothermic extracorporeal perfusion of isolated human liver after warm ischaemia: a preliminary report.

    Science.gov (United States)

    Bellomo, Rinaldo; Marino, Bruno; Starkey, Graeme; Fink, Michael; Wang, Bao Zhong; Eastwood, Glenn M; Peck, Leah; Young, Helen; Houston, Shane; Skene, Alison; Opdam, Helen; Jones, Robert

    2014-09-01

    Donation after circulatory death (DCD) livers are at markedly increased risk of primary graft dysfunction and biliary tract ischaemia. Normothermic extracorporeal liver perfusion (NELP) may increase the ability to transplant DCD livers and may allow their use for artificial extracorporeal liver support of patients with fulminant liver failure. We conducted two proof-of-concept experiments using human livers after DCD to assess the feasibility and functional efficacy of NELP over an extended period. We applied extracorporeal membrane oxygenation, parenteral nutrition, separate hepatic artery and portal vein perfusion and physiological perfusion pressures to two livers obtained after DCD. We achieved NELP and evidence of liver function (bile production, paracetamol removal and maintenance of normal lactate levels) in both livers; one for 24 hours and the other for 43 hours. Histological examination showed areas of patchy ischaemia but preserved biliary ducts and canaliculi. Our experiments justify further investigations of the feasibility and efficacy of extended DCD liver preservation by ex-vivo perfusion.

  4. Perfusion abnormalities in congenital and neoplastic pulmonary disease: comparison of MR perfusion and multislice CT imaging

    International Nuclear Information System (INIS)

    Boll, Daniel T.; Lewin, Jonathan S.; Young, Philip; Gilkeson, Robert C.; Siwik, Ernest S.

    2005-01-01

    The aim of this work was to assess magnetic resonance (MR) perfusion patterns of chronic, nonembolic pulmonary diseases of congenital and neoplastic origin and to compare the findings with results obtained with pulmonary, contrast-enhanced multislice computed tomography (CT) imaging to prove that congenital and neoplastic pulmonary conditions require MR imaging over the pulmonary perfusion cycle to successfully and directly detect changes in lung perfusion patterns. Twenty-five patients underwent concurrent CT and MR evaluation of chronic pulmonary diseases of congenital (n=15) or neoplastic (n=10) origin. Analysis of MR perfusion and contrast-enhanced CT datasets was realized by defining pulmonary and vascular regions of interest in corresponding positions. MR perfusion calculated time-to-peak enhancement, maximal enhancement and the area under the perfusion curve. CT datasets provided pulmonary signal-to-noise ratio measurements. Vessel centerlines of bronchial arteries were determined. Underlying perfusion type, such as pulmonary arterial or systemic arterial supply, as well as regions with significant variations in perfusion were determined statistically. Analysis of the pulmonary perfusion pattern detected pulmonary arterial supply in 19 patients; six patients showed systemic arterial supply. In pulmonary arterial perfusion, MR and multislice CT imaging consistently detected the perfusion type and regions with altered perfusion patterns. In bronchial arterial supply, MR perfusion and CT imaging showed significant perfusion differences. Patients with bronchial arterial supply had bronchial arteries ranging from 2.0 to 3.6 mm compared with submillimeter diameters in pulmonary arterial perfusion. Dynamic MR imaging of congenital and neoplastic pulmonary conditions allowed characterization of the pulmonary perfusion type. CT imaging suggested the presence of systemic arterial perfusion by visualizing hypertrophied bronchial arteries. (orig.)

  5. MR-based assessment of pulmonary ventilation-perfusion in animal models

    International Nuclear Information System (INIS)

    Yang Jian; Wan Mingxi; Guo Youmin

    2003-01-01

    Objective: To show the feasibility and value in the diagnosis of airway obstruction and pulmonary embolism with MR oxygen-enhanced ventilation combined with pulmonary perfusion imaging. Methods: Eight canines were implemented for peripheral pulmonary embolism by intravenous injection of gelfoam granules at pulmonary segmental arterial level, and five of them were formed airway obstruction models by inserting self-made balloon catheter at second-bronchia. The oxygen-enhanced MR ventilation imaging was introduced by subtracting the images of pre- and post- inhaled pure oxygen. The MR pulmonary perfusion imaging was achieved by the first-pass contrast agent method. Moreover, the manifestation of MR ventilation and perfusion imaging was observed and contradistinguished with that of general pathologic anatomy, ventilation-perfusion scintigraphy, and pulmonary angiography. Results: The manifestations of airway obstruction regions in MR ventilation and perfusion imaging were matched, but those of pulmonary embolism regions were dismatched. The defect range of airway obstruction in MR ventilation image was smaller than that in ventilation scintigraphy. The abnormal perfusion regions of pulmonary embolism were divided into defect regions and reduce regions based on the time courses of signal intensity changes. The sensitivity and specificity of diagnosis on pulmonary embolism by MR ventilation combined with perfusion technique were 75.0% and 98.1%. The diagnostic results were in good coherence with ventilation-perfusion scintigraphy and pulmonary angiography (K=0.743, 0.899). Conclusion: The MR oxygen-enhanced ventilation combined with pulmonary perfusion imaging can be used to diagnose the airway and vascular abnormity in lung. This technique resembles the ventilation-perfusion scintigraphy. It can provide quantitative functional information and better spatial and temporal resolution, and possesses the value of clinical application

  6. Reducing the fuel temperature for pressure-tube supercritical-water-cooled reactors and the effect of fuel burnup

    Energy Technology Data Exchange (ETDEWEB)

    Nichita, E., E-mail: eleodor.nichita@uoit.ca; Kovaltchouk, V., E-mail: vitali.kovaltchouk@uoit.ca

    2015-12-15

    Highlights: • Typical PT-SCWR fuel uses single-region pins consisting of a homogeneous mixture of ThO{sub 2} and PuO{sub 2}. • Using two regions (central for the ThO{sub 2} and peripheral for the PuO{sub 2}) reduces the fuel temperature. • Single-region-pin melting-to-average power ratio is 2.5 at 0.0 MW d/kg and 2.3 at 40 MW d/kg. • Two-region-pin melting-to-average power ratio is 36 at 0.0 MW d/kg and 10.5 at 40 MW d/kg. • Two-region-pin performance drops with burnup due to fissile-element buildup in the ThO{sub 2} region. - Abstract: The Pressure-Tube Supercritical-Water-Cooled Reactor (PT-SCWR) is one of the concepts under investigation by the Generation IV International Forum for its promise to deliver higher thermal efficiency than nuclear reactors currently in operation. The high coolant temperature (>625 K) and high linear power density employed by the PT-SCWR cause the fuel temperature to be fairly high, leading to a reduced margin to fuel melting, thus increasing the risk of actual melting during accident scenarios. It is therefore desirable to come up with a fuel design that lowers the fuel temperature while preserving the high linear power ratio and high coolant temperature. One possible solution is to separate the fertile (ThO{sub 2}) and fissile (PuO{sub 2}) fuel materials into different radial regions in each fuel pin. Previously-reported work found that by locating the fertile material at the centre and the fissile material at the periphery of the fuel pin, the fuel centreline temperature can be reduced by ∼650 K for fresh fuel compared to the case of a homogeneous (Th–Pu)O{sub 2} mixture for the same coolant temperature and linear power density. This work provides a justification for the observed reduction in fuel centreline temperature and suggests a systematic approach to lower the fuel temperature. It also extends the analysis to the dependence of the radial temperature profile on fuel burnup. The radial temperature profile is

  7. Correlation of the myocardial perfusion corrected by attenuation with the coronariography. Preliminary results; Correlacion de la perfusion miocardica corregida por atenuacion con la coronariografia

    Energy Technology Data Exchange (ETDEWEB)

    Garcia C, S.E.; Garcia O, R. [Servicio de Medicina Nuclear, Centro Medico ABC, Campis Observatorio, IAP (Mexico)

    2005-07-01

    The attenuation that suffers the radiation in the soft tissues of the hinders the appropriate interpretation of the myocardial perfusion studies, for what have been implemented attenuation correction systems to reduce the attenuation for soft tissues and to provide myocardial perfusion images more accurate in the diagnosis of coronary illness. The objective was to evaluate the utility of an attenuation correction system (with source of Gadolinium 153) to minimize the devices that look like true defects of myocardial perfusion, caused by soft tissues (mammary tissue, thoracic wall, abdomen, left hemi diaphragm), and to compare those interpretations of the studies with the interpretations of the corresponding coronariographies. The method consists of 95 electronic files which were revised with the concept of heart catheterization, being identified 20 patients from the masculine sex to those that underwent coronariography among May 1999 and December 2002, and that they had study of myocardial perfusion in a maximum period of 3 months foresaw to the invasive procedure. (Author)

  8. Short communication: Is consumption of a cheese rich in angiotensin-converting enzyme-inhibiting peptides, such as the Norwegian cheese Gamalost, associated with reduced blood pressure?

    Science.gov (United States)

    Nilsen, R; Pripp, A H; Høstmark, A T; Haug, A; Skeie, S

    2014-05-01

    Epidemiological and clinical studies have shown that angiotensin-converting enzyme (ACE)-inhibiting peptides derived from dairy products may decrease blood pressure. These peptides have been identified in many cheeses, and Gamalost, a traditional Norwegian cheese, is particularly rich in these peptides. The aim of this cross-sectional study was to examine whether frequency of Gamalost intake was associated with blood pressure in a Norwegian population sample. Blood pressure and other clinical measurements, including the factors of metabolic syndrome, were obtained from 168 participants (56% female, mean age = 51 yr) who completed a questionnaire about dietary habits and other health-related factors. Mean Gamalost intake was 2 servings per week. The prevalence of hypertension was 23.8% in the population, with mean systolic and diastolic blood pressures of 128 and 78 mmHg, respectively. Intake of Gamalost was inversely associated with systolic blood pressure. Each increase in frequency unit of Gamalost intake corresponded to a reduction in systolic blood pressure of 0.72 mmHg, after controlling for sex, age, education, waist circumference, physical activity, smoking status, and dairy food intake. Results from this study indicate that consumption of Gamalost (or other foods rich in ACE-inhibiting peptides) may reduce blood pressure. Copyright © 2014 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  9. Development of a higher capacity, lower pressure drop steam/water separator with reduced primary-to-secondary spacing

    International Nuclear Information System (INIS)

    Pruster, W.P.; Kidwell, J.H.; Eaton, A.M.; Wall, J.R.

    1985-01-01

    The goal of this development effort was to double the steam flow capacity of an existing module steam/water separator design without significantly increasing the pressure drop while simultaneously minimizing the vertical distance (spacing) between the primary and secondary separation stages. The development work included extensive air/water and steam/water testing. The steam/water tests were performed at a common pressure of 300 psia (2.1 MPa) with comparable water and steam flows

  10. Camphor-Crataegus berry extract combination dose-dependently reduces tilt induced fall in blood pressure in orthostatic hypotension.

    Science.gov (United States)

    Belz, G G; Butzer, R; Gaus, W; Loew, D

    2002-10-01

    In order to test the efficacy of a combination of natural D-camphor and an extract of fresh crataegus berries (Korodin Herz-Kreislauf-Tropfen) on orthostatic hypotension, two similar, controlled, randomized studies were carried out in a balanced crossover design in 24 patients each with orthostatic dysregulation. The camphor-crataegus berry combination (CCC) was orally administered as a single regimen in 3 different dosages of 5 drops, 20 drops and 80 drops; a placebo with 20 drops of a 60% alcoholic solution served as control. Orthostatic hypotension was assessed with the tilt table test before and after medication. Source data of both studies were pooled and meta-analytically evaluated for all 48 patients. CCC drops decreased the orthostatic fall in blood pressure versus placebo, as almost uniformly established at all times by mean arterial pressure and diastolic blood pressure. Mean arterial pressure demonstrated the very fast onset of action by a clearly dose-dependent statistically significant effect even after 1-minute orthostasis. Increase of mean arterial pressure as compared to the orthostasis test before medication was on average 4.5 mmHg. CCC affected diastolic blood pressure after 1 minute of orthostasis in all dosages as compared to placebo. A statistically significant effect of the highest dose of 80 drops on diastolic blood pressure could be demonstrated after 1-, 3-, and 5-minute orthostasis. The hemodynamic findings of a stabilizing effect on arterial pressure in orthostasis corroborate the long-term medical experience with CCC and justify the indication orthostatic hypotension.

  11. TIPS bilateral noise reduction in 4D CT perfusion scans produces high-quality cerebral blood flow maps

    NARCIS (Netherlands)

    A. Mendrik (Adrienne); E.J.P.A. Vonken; B.T.J. van Ginneken (Berbke); J.R. Riordan (John ); H.W.A.M. de Jong (Hugo); T. van Seeters (Tom); E.J. Smit (Ewoud); M.A. Viergever (Max); M. Prokop (Mathias)

    2011-01-01

    textabstractCerebral computed tomography perfusion (CTP) scans are acquired to detect areas of abnormal perfusion in patients with cerebrovascular diseases. These 4D CTP scans consist of multiple sequential 3D CT scans over time. Therefore, to reduce radiation exposure to the patient, the amount of

  12. Effect of forced-air heaters on perfusion and temperature distribution during and after open-heart surgery

    NARCIS (Netherlands)

    Severens, Natascha M. W.; van Marken Lichtenbelt, Wouter D.; van Leeuwen, Gerard M. J.; Frijns, Arjan J. H.; van Steenhoven, Anton A.; de Mol, Bas A. J. M.; van Wezel, Harry B.; Veldman, Dirk J.

    2007-01-01

    OBJECTIVES: After cardiopulmonary bypass, patients often show redistribution hypothermia, also called afterdrop. Forced-air blankets help to reduce afterdrop. This study explores the effect of forced-air blankets on temperature distribution and peripheral perfusion. The blood perfusion data is used

  13. Effect of forced-air heaters on perfusion and and temperature distribution during and after open-heart surgery

    NARCIS (Netherlands)

    Severens, N.M.W.; Marken Lichtenbelt, van W.; Leeuwen, van G.M.J.; Frijns, A.J.H.; Steenhoven, van A.A.; Mol, de B.A.J.M.; Wezel, H.B.; Veldman, D.J.

    2007-01-01

    Objectives: After cardiopulmonary bypass, patients often show redistribution hypothermia, also called afterdrop. Forced-air blankets help to reduce afterdrop. This study explores the effect of forced-air blankets on temperature distribution and peripheral perfusion. The blood perfusion data is used

  14. Physical activity reduces systemic blood pressure and improves early markers of atherosclerosis in pre-pubertal obese children.

    Science.gov (United States)

    Farpour-Lambert, Nathalie J; Aggoun, Yacine; Marchand, Laetitia M; Martin, Xavier E; Herrmann, François R; Beghetti, Maurice

    2009-12-15

    The aim of this study was to determine the effects of physical activity on systemic blood pressure (BP) and early markers of atherosclerosis in pre-pubertal obese children. Hypertension and endothelial dysfunction are premature complications of obesity. We performed a 3-month randomized controlled trial with a modified crossover design: 44 pre-pubertal obese children (age 8.9 + or - 1.5 years) were randomly assigned (1:1) to an exercise (n = 22) or a control group (n = 22). We recruited 22 lean children (age 8.5 + or - 1.5 years) for baseline comparison. The exercise group trained 60 min 3 times/week during 3 months, whereas control subjects remained relatively inactive. Then, both groups trained twice/week during 3 months. We assessed changes at 3 and 6 months in office and 24-h BP, arterial intima-media thickness (IMT) and stiffness, endothelial function (flow-mediated dilation), body mass index (BMI), body fat, cardiorespiratory fitness (maximal oxygen consumption [VO(2)max]), physical activity, and biological markers. Obese children had higher BP, arterial stiffness, body weight, BMI, abdominal fat, insulin resistance indexes, and C-reactive protein levels, and lower flow-mediated dilation, VO(2)max, physical activity, and high-density lipoprotein cholesterol levels than lean subjects. At 3 months, we observed significant changes in 24-h systolic BP (exercise -6.9 + or - 13.5 mm Hg vs. control 3.8 + or - 7.9 mm Hg, -0.8 + or - 1.5 standard deviation score [SDS] vs. 0.4 + or - 0.8 SDS), diastolic BP (-0.5 + or - 1.0 SDS vs. 0 + or - 1.4 SDS), hypertension rate (-12% vs. -1%), office BP, BMI z-score, abdominal fat, and VO(2)max. At 6 months, change differences in arterial stiffness and IMT were significant. A regular physical activity program reduces BP, arterial stiffness, and abdominal fat; increases cardiorespiratory fitness; and delays arterial wall remodeling in pre-pubertal obese children. (Effects of Aerobic Exercise Training on Arterial Function and

  15. Normal anatomy of lung perfusion SPECT scintigraphy

    International Nuclear Information System (INIS)

    Moskowitz, G.W.; Levy, L.M.

    1987-01-01

    Ten patients studies for possible pulmonary embolic disease had normal lung perfusion planar and SPECT scintigraphy. A computer program was developed to superimpose the CT scans on corresponding SPECT images. Superimposition of CT scans on corresponding SPECT transaxial cross-sectional images, when available, provides the needed definition and relationships of adjacent organs. SPECT transaxial sections provide clear anatomic definition of perfusion defects without foreground and background lung tissue superimposed. The location, shape, and size of the perfusion defects can be readily assessed by SPECT. An algorithm was developed for the differentiation of abnormal pulmonary perfusion patterns from normal structures on variation

  16. Irradiated ignition over solid materials in reduce pressure environment: Fire safety issue in man-made enclosure system

    Science.gov (United States)

    Nakamura, N.; Aoki, A.

    Effects of ambient pressure and oxygen yield on irradiated ignition characteristics over solid combustibles have been studied experimentally Aim of the present study is to elucidate the flammability and chance of fire in depressurized enclosure system and give ideas for the fire safety and fire fighting strategies in such environment Thin cellulosic paper is considered as the solid combustible since cellulose is one of major organic compounds and flammables in the nature Applied atmosphere consists of inert gas either CO2 or N2 and oxygen and various mixture ratios are of concerned Total ambient pressure level is varied from 0 1MPa standard atmospheric pressure to 0 02MPa Ignition is initiated by external thermal flux exposed into the solid surface as a model of unexpected thermal input to initiate the localized fire Thermal degradation of the solid induces combustible gaseous products e g CO H2 or other low class of HCs and the gas mixes with ambient oxygen to form the combustible mixture over the solid Heat transfer from the hot irradiated surface into the mixture accelerates the local exothermic reaction in the gas phase and finally thermal runaway ignition is achieved Ignition event is recorded by high-speed digital video camera to analyze the ignition characteristics Flammable map in partial pressure of oxygen Pox and total ambient pressure Pt plane is made to reveal the fire hazard in depressurized environment Results show that wider flammable range is obtained depending on the imposed ambient

  17. Self-regulation and social pressure reduce prejudiced responding and increase the motivation to be non-prejudiced.

    Science.gov (United States)

    Buzinski, Steven G; Kitchens, Michael B

    2017-01-01

    Self-regulation constrains the expression of prejudice, but when self-regulation falters, the immediate environment can act as an external source of prejudice regulation. This hypothesis derives from work demonstrating that external controls and internal self-regulation can prompt goal pursuit in the absence of self-imposed controls. Across four studies, we found support for this complementary model of prejudice regulation. In Study 1, self-regulatory fatigue resulted in less motivation to be non-prejudiced, compared to a non-fatigued control. In Study 2, strong (vs. weak) perceived social pressure was related to greater motivation to be non-prejudiced. In Study 3, dispositional self-regulation predicted non-prejudice motivation when perceived social pressure was weak or moderate, but not when it was strong. Finally, in Study 4 self-regulatory fatigue increased prejudice when social pressure was weak but not when it was strong.

  18. Laminar burning velocity and Markstein length of nitrogen diluted natural gas/hydrogen/air mixtures at normal, reduced and elevated pressures

    Energy Technology Data Exchange (ETDEWEB)

    Miao, Haiyan [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Eng., Xi' an Jiaotong University (China); Institute of High Performance Computing, A-star (Singapore); Ji, Min; Jiao, Qi; Huang, Qian; Huang, Zuohua [State Key Laboratory of Multiphase Flow in Power Engineering, School of Energy and Power Eng., Xi' an Jiaotong University (China)

    2009-04-15

    Flame propagation of premixed nitrogen diluted natural gas/hydrogen/air mixtures was studied in a constant volume combustion bomb under various initial pressures. Laminar burning velocities and Markstein lengths were obtained for the diluted stoichiometric fuel/air mixtures with different hydrogen fractions and diluent ratios under various initial pressures. The results showed that both unstretched flame speed and unstretched burning velocity are reduced with the increase in initial pressure (except when the hydrogen fraction is 80%) as well as diluent ratio. The velocity reduction rate due to diluent addition is determined mainly by hydrogen fraction and diluent ratio, and the effect of initial pressure is negligible. Flame stability was studied by analyzing Markstein length. It was found that the increase of initial pressure and hydrogen fraction decreases flame stability and the flame tends to be more stable with the addition of diluent gas. Generally speaking, Markstein length of a fuel with low hydrogen fraction is more sensitive to the change of initial pressure than that of a one with high hydrogen fraction. (author)

  19. Cerebral perfusion alterations in epileptic patients during peri-ictal and post-ictal phase: PASL vs DSC-MRI.

    Science.gov (United States)

    Pizzini, Francesca B; Farace, Paolo; Manganotti, Paolo; Zoccatelli, Giada; Bongiovanni, Luigi G; Golay, Xavier; Beltramello, Alberto; Osculati, Antonio; Bertini, Giuseppe; Fabene, Paolo F

    2013-07-01

    Non-invasive pulsed arterial spin labeling (PASL) MRI is a method to study brain perfusion that does not require the administration of a contrast agent, which makes it a valuable diagnostic tool as it reduces cost and side effects. The purpose of the present study was to establish the viability of PASL as an alternative to dynamic susceptibility contrast (DSC-MRI) and other perfusion imaging methods in characterizing changes in perfusion patterns caused by seizures in epileptic patients. We evaluated 19 patients with PASL. Of these, the 9 affected by high-frequency seizures were observed during the peri-ictal period (within 5hours since the last seizure), while the 10 patients affected by low-frequency seizures were observed in the post-ictal period. For comparison, 17/19 patients were also evaluated with DSC-MRI and CBF/CBV. PASL imaging showed focal vascular changes, which allowed the classification of patients in three categories: 8 patients characterized by increased perfusion, 4 patients with normal perfusion and 7 patients with decreased perfusion. PASL perfusion imaging findings were comparable to those obtained by DSC-MRI. Since PASL is a) sensitive to vascular alterations induced by epileptic seizures, b) comparable to DSC-MRI for detecting perfusion asymmetries, c) potentially capable of detecting time-related perfusion changes, it can be recommended for repeated evaluations, to identify the epileptic focus, and in follow-up and/or therapy-response assessment. Copyright © 2013 Elsevier Inc. All rights reserved.

  20. Intravoxel incoherent motion perfusion imaging in acute stroke: initial clinical experience

    International Nuclear Information System (INIS)

    Federau, C.; Becce, F.; Maeder, P.; Meuli, R.; Sumer, S.; Wintermark, M.; O'Brien, K.

    2014-01-01

    Intravoxel incoherent motion (IVIM) imaging is an MRI perfusion technique that uses a diffusion-weighted sequence with multiple b values and a bi-compartmental signal model to measure the so-called pseudo-diffusion of blood caused by its passage through the microvascular network. The goal of the current study was to assess the feasibility of IVIM perfusion fraction imaging in patients with acute stroke. Images were collected in 17 patients with acute stroke. Exclusion criteria were onset of symptoms to imaging >5 days, hemorrhagic transformation, infratentorial lesions, small lesions 2 . Image quality was assessed by two radiologists, and quantitative analysis was performed in regions of interest placed in the stroke area, defined by thresholding the apparent diffusion coefficient maps, as well as in the contralateral region. IVIM perfusion fraction maps showed an area of decreased perfusion fraction f in the region of decreased apparent diffusion coefficient. Quantitative analysis showed a statistically significant decrease in both IVIM perfusion fraction f (0.026 ± 0.019 vs. 0.056 ± 0.025, p = 2.2 . 10 -6 ) and diffusion coefficient D compared with the contralateral side (3.9 ± 0.79 . 10 -4 vs. 7.5 ± 0.86 . 10 -4 mm 2 /s, p = 1.3 . 10 -20 ). IVIM perfusion fraction imaging is feasible in acute stroke. IVIM perfusion fraction is significantly reduced in the visible infarct. Further studies should evaluate the potential for IVIM to predict clinical outcome and treatment response. (orig.)

  1. Transplacental pharmacokinetics of diclofenac in perfused human placenta.

    Science.gov (United States)

    Shintaku, Kyohei; Hori, Satoko; Tsujimoto, Masayuki; Nagata, Hideaki; Satoh, Shoji; Tsukimori, Kiyomi; Nakano, Hitoo; Fujii, Tomoyuki; Taketani, Yuji; Ohtani, Hisakazu; Sawada, Yasufumi

    2009-05-01

    The aims of this study were to evaluate the transplacental transfer properties of diclofenac and to determine the effect of L-lactic acid on the transplacental transfer of diclofenac. The maternal and fetal vessels of human placenta were perfused in a single-pass mode with a solution containing diclofenac and antipyrine. The transplacental pharmacokinetic model was fitted to the time profiles of the drug concentrations in the effluent and placenta to obtain transplacental pharmacokinetic parameters. In addition, chloride ion in the perfusate was partially replaced with L-lactic acid to see the change in the transplacental transfer properties of diclofenac. The TPT(ss) value (ratio of the rate of amount transferred across the placenta to that infused in the steady state) of diclofenac was 2.22%, which was approximately one-third that of antipyrine and was significantly reduced in the presence of L-lactic acid. The transplacental pharmacokinetic model could adequately explain the transplacental transfer of diclofenac with influx clearances from maternal and fetal perfusates to placental tissue of 0.276 and 0.0345 ml/min/g cotyledon and efflux rate constants from placental tissue to maternal and fetal perfusates of 0.406 and 0.0337 min(-1), respectively. By taking into account protein binding, the placental tissue/plasma concentration ratio in humans for diclofenac was estimated to be 0.108 ml/g of cotyledon and was smaller than that of antipyrine. In conclusion, human placental perfusion and transplacental pharmacokinetic modeling allowed us to determine the transplacental transfer properties of diclofenac quantitatively. Diclofenac may share transplacental transfer system(s) with L-lactic acid.

  2. Effects of an alveolar recruitment maneuver on subdural pressure, brain swelling, and mean arterial pressure in patients undergoing supratentorial tumour resection: a randomized crossover study.

    Science.gov (United States)

    Flexman, Alana M; Gooderham, Peter A; Griesdale, Donald E; Argue, Ruth; Toyota, Brian

    2017-06-01

    Although recruitment maneuvers have been advocated as part of a lung protective ventilation strategy, their effects on cerebral physiology during elective neurosurgery are unknown. Our objectives were to determine the effects of an alveolar recruitment maneuver on subdural pressure (SDP), brain relaxation score (BRS), and cerebral perfusion pressure among patients undergoing supratentorial tumour resection. In this prospective crossover study, patients scheduled for resection of a supratentorial brain tumour were randomized to undergo either a recruitment maneuver (30 cm of water for 30 sec) or a "sham" maneuver (5 cm of water for 30 sec), followed by the alternative intervention after a 90-sec equilibration period. Subdural pressure was measured through a dural perforation following opening of the cranium. Subdural pressure and mean arterial pressure (MAP) were recorded continuously. The blinded neurosurgeon provided a BRS at baseline and at the end of each intervention. During each treatment, the changes in SDP, BRS, and MAP were compared. Twenty-one patients underwent the study procedure. The increase in SDP was higher during the recruitment maneuver than during the sham maneuver (difference, 3.9 mmHg; 95% confidence interval [CI], 2.2 to 5.6; P < 0.001). Mean arterial pressure decreased further in the recruitment maneuver than in the sham maneuver (difference, -9.0 mmHg; 95% CI, -12.5 to -5.6; P < 0.001). Cerebral perfusion pressure decreased 14 mmHg (95% CI, 4 to 24) during the recruitment maneuver. The BRS did not change with either maneuver. Our results suggest that recruitment maneuvers increase subdural pressure and reduce cerebral perfusion pressure, although the clinical importance of these findings is thus far unknown. This trial was registered with ClinicalTrials.gov, NCT02093117.

  3. CHF experiments of tight pitch lattice rod bundles under PWR pressure condition for development of reduced moderation water reactor

    International Nuclear Information System (INIS)

    Araya, Fumimasa; Nakatsuka, Toru; Yoritsune, Tsutomu

    2002-10-01

    In order to improve plutonium utilization, design studies of reduced moderation water reactors which have hard neutron energy spectrum have been carried out at Division of Energy System Research of Japan Atomic Energy Research Institute (JAERI). At present, triangle, tight pitch lattice cores with about 1 mm gap width between fuel rods have been focused in the neutronic core design. Since a degradation of the heat removal from the fuel rods is worried, an evaluation of heat removal capability i.e. critical heat flux becomes one of important evaluation items in the feasibility study. However, any of published data base, which can be applicable to the evaluation on such narrow gap width cores, does not exist. Therefore, in the present study, in order to accumulate applicable data and to confirm applicability of an evaluation methodology of critical heat flux, basic experiments on the critical heat flux were performed using the test sections consisted of 7 heater rods bundles with the gap widths of 1.5, 1.0 and 0.6 mm under the PWR pressure conditions. The present report describes the experimental apparatus, experimental conditions and accumulated data. Analysis results of the data and the applicability of the evaluation methodology used for the design work are also discussed in this report. As the results of the experiment, it was found that the critical heat flux increased as the mass flux and the inlet subcooling increased. In the region of the mass flux less than about 2,000 kg/m 2 /s, the critical heat flux decreased as the gap width decreased. In the larger mass flux region, obvious trend of effects of the gap width on critical heat flux were not observed due to data scatterings. The flow-area-averaged thermal-equilibrium quality at the CHF position was in the higher ranges from 0.3 to 0.8 in the cases of gap widths of 1.0 and 0.6 mm, and 0.1 to 0.3 in the 1.5 mm case. Based on the experimental results such that the CHFs occurred in the higher quality range and

  4. Effects of the repeated administration of adenosine and heparin on myocardial perfusion in patients with chronic stable angina pectoris.

    Science.gov (United States)

    Barron, H V; Sciammarella, M G; Lenihan, K; Michaels, A D; Botvinick, E H

    2000-01-01

    The mechanism by which ischemia stimulates angiogenesis is unknown. Adenosine is released during myocardial ischemia and may be a mediator of this process. Experimental data suggest that heparin may enhance this effect. The purpose of this open-labeled, placebo-controlled trial was to determine whether repeated intravenous administration of adenosine and heparin could mimic physiologic angiogenesis and reduce the amount of exercise-induced myocardial ischemia in patients with coronary artery disease. Subjects with chronic stable angina refractory to conventional medical therapy and not suitable for revascularization received either adenosine (140 microg/kg/min for 6 minutes) and heparin (10,000 U bolus), (n = 14), or placebo, (n = 7) daily for 10 days. All patients underwent baseline and follow-up exercise testing with thallium-201 single-photon emission computed tomography myocardial perfusion imaging. A semiquantitative assessment of the extent and severity of the perfusion abnormalities was calculated by 2 blinded investigators. There was no significant change in exercise duration or in the peak heart rate systolic blood pressure product associated with adenosine and heparin compared with placebo treatment. There was, however, a 9% reduction in the extent (60.6 +/- 4.0 vs 54.9 +/- 4.1, p = 0.03) and a 14% improvement in severity (41.5 +/- 3.2 vs 35.7 +/- 2.9, p = 0.01) of the myocardial perfusion abnormalities seen in patients who received adenosine and heparin compared with placebo. Thus, in this pilot study, repeated administration of adenosine and heparin reduced the amount of exercise-induced ischemia in patients with chronic stable angina refractory to conventional treatment.

  5. Quantification of absolute myocardial perfusion at rest and during exercise with positron emission tomography after human cardiac transplantation

    International Nuclear Information System (INIS)

    Krivokapich, J.; Stevenson, L.W.; Kobashigawa, J.; Huang, S.C.; Schelbert, H.R.

    1991-01-01

    The maximal exercise capacity of cardiac transplant recipients is reduced compared with that of normal subjects. To determine if this reduced exercise capacity is related to inadequate myocardial perfusion during exercise, myocardial perfusion was measured noninvasively with use of positron emission tomography and nitrogen (N)-13 ammonia. Twelve transplant recipients with no angiographic evidence of accelerated coronary atherosclerosis were studied. Serial N-13 ammonia imaging was performed at rest and during supine bicycle exercise. The results were compared with those from 10 normal volunteers with a low probability of having cardiac disease. A two-compartment kinetic model for estimating myocardial perfusion was applied to the data. Transplant recipients achieved a significant lower exercise work load than did the volunteers (42 ± 16 vs. 128 ± 22 W), but a higher venous lactate concentration (31.3 ± 14.9 vs. 13.7 ± 4.1 mg/100 ml). Despite the difference in exercise work load, there was no significant difference in the cardiac work achieved by transplant recipients and normal subjects as evidenced by similar rate-pressure products of 24,000 ± 3,400 versus 21,300 ± 2,800 betas/min per mm Hg, respectively. In addition, myocardial blood flow during exercise was not significantly different between the two groups (1.70 ± 0.60 vs. 1.56 ± 0.71 ml/min per g, respectively). This study demonstrates that the myocardial flow response to the physiologic stress of exercise is appropriate in transplant recipients and does not appear to explain the decreased exercise capacity in these patients

  6. Tyrosine improves cognitive performance and reduces blood pressure in cadets after one week of combat training course

    NARCIS (Netherlands)

    Deijen, J.B.; Wientjes, C.J.E.; Vullinghs, H.F.M.; Cloin, P.A.; Langeveld, J.J.

    1999-01-01

    The effect of the amino acid tyrosine on cognitive task performance were studied on a group of 21 cadets during a demanding military combat training course. In addition, the effects on mood, blood pressure and the norepinephrine metabolite MHPG were determined. Ten subjects received five daily doses

  7. WATER EXTRACT OF PURPLE SWEET POTATO TUBERS REDUCES BLOOD PRESSURE 0F HYPERTENSIVE RATS INDUCED BY NaCl

    Directory of Open Access Journals (Sweden)

    I MADE JAWI

    2013-04-01

    Full Text Available Compliance of hypertensive patients to take medication is one of many determinant factors to achieve successful treatment. Side effects and the expensive price of drugs are the causes of the incompliance of patients taking the medication. Utilization of herbal medicine is a new hope to resolve the issue. Purple sweet potato tuber is a plant part that expected has beneficial effect in lowering blood pressure because it contains anthocyanins which are antioxidants and can preserve endothelial function. To prove these hypothesis, a study was conducted with randomized control group pre and post-test design. The  study was done on 20 adult male Wistar rats that were divided into two groups of 10 rats.  Both groups of rats were made hypertensive by administering high doses of NaCl. Control group of rats given only NaCl alone for 14 days. Treatment group were given NaCl and water extract of purple sweet potato tuber with a dose of 4 cc per day for 14 days. Before treatment and during treatment, blood pressure were taken everyday with special sphygmomanometer. The results indicate a significant difference in blood pressure between the control group with treatment (P = 0.0001. In the treatment group, it was observed that there was a significant decrease in blood pressure compared to the control group (P=0.0001. From the results of this study, it can be concluded that administration of purple sweet potato tuber water extract may lower high blood pressure of rats induced by NaCl.

  8. Blood pressure and the contractility of a human leg muscle.

    Science.gov (United States)

    Luu, Billy L; Fitzpatrick, Richard C

    2013-11-01

    These studies investigate the relationships between perfusion pressure, force output and pressor responses for the contracting human tibialis anterior muscle. Eight healthy adults were studied. Changing the height of tibialis anterior relative to the heart was used to control local perfusion pressure. Electrically stimulated tetanic force output was highly sensitive to physiological variations in perfusion pressure showing a proportionate change in force output of 6.5% per 10 mmHg. This perfusion-dependent change in contractility begins within seconds and is reversible with a 53 s time constant, demonstrating a steady-state equilibrium between contractility and perfusion pressure. These stimulated contractions did not produce significant cardiovascular responses, indicating that the muscle pressor response does not play a major role in cardiovascular regulation at these workloads. Voluntary contractions at forces that would require constant motor drive if perfusion pressure had remained constant generated a central pressor response when perfusion pressure was lowered. This is consistent with a larger cortical drive being required to compensate for the lost contractility with lower perfusion pressure. The relationship between contractility and perfusion for this large postural muscle was not different from that of a small hand muscle (adductor pollicis) and it responded similarly to passive peripheral and active central changes in arterial pressure, but extended over a wider operating range of pressures. If we consider that, in a goal-oriented motor task, muscle contractility determines central motor output and the central pressor response, these results indicate that muscle would fatigue twice as fast without a pressor response. From its extent, timing and reversibility we propose a testable hypothesis that this change in contractility arises through contraction- and perfusion-dependent changes in interstitial K(+) concentration.

  9. Fatty acid utilization in pressure-overload hypertrophied rat hearts

    International Nuclear Information System (INIS)

    Reibel, D.K.; O'Rourke, B.

    1986-01-01

    The authors have previously shown that the levels of total tissue coenzyme A and carnitine are reduced in hypertrophied hearts of rats subjected to aortic constriction. It was therefore of interest to determine if these changes were associated with alterations in fatty acid oxidation by the hypertrophied myocardium. Hearts were excised from sham-operated and aortic-constricted rats and perfused at 10 cm H 2 O left atrial filling pressure with a ventricular afterload of 80 cm of H 2 O with buffer containing 1.2 mM 14 C-linoleate. Heart rate and peak systolic pressure were not different in control and hypertrophied hearts. 14 CO 2 production was linear in both groups of hearts between 10 and 30 minutes of perfusion. The rate of fatty acid oxidation determined by 14 CO 2 production during this time was 0.728 +/- 0.06 μmoles/min/g dry in control hearts and 0.710 +/- 0.02 μmoles/min/g dry in hypertrophied hearts. Comparable rates of fatty acid oxidation were associated with comparable rates of O 2 consumption in the two groups of hearts (39.06 +/- 3.50 and 36.78 +/- 2.39 μmoles/g dry/min for control and hypertrophied hearts, respectively). The data indicate that the ability of the hypertrophied heart to oxidize fatty acids under these perfusion conditions is not impaired in spite of significant reductions in tissue levels of coenzyme A and carnitine

  10. Magnetic resonance myocardial perfusion imaging-First experience at 3.0 T

    Energy Technology Data Exchange (ETDEWEB)

    Klumpp, B. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: bernhard.klumpp@med.uni-tuebingen.de; Hoevelborn, T. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Cardiology, Otfried-Mueller-Str. 10, 72076 Tuebingen (Germany)], E-mail: tobias.hoevelborn@gmx.de; Fenchel, M. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: michael.fenchel@med.uni-tuebingen.de; Stauder, N.I. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: norbert.stauder@stgag.ch; Kramer, U. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: ulrich.kramer@med.uni-tuebingen.de; May, A. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Cardiology, Otfried-Mueller-Str. 10, 72076 Tuebingen (Germany)], E-mail: andreas.may@med.uni-tuebingen.de; Gawaz, M.P. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Cardiology, Otfried-Mueller-Str. 10, 72076 Tuebingen (Germany)], E-mail: meinrad.gawaz@med.uni-tuebingen.de; Claussen, C.D. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: claus.claussen@med.uni-tuebingen.de; Miller, S. [Eberhard-Karls-University Tuebingen, University Hospital Tuebingen, Department of Diagnostic Radiology, Hoppe-Seyler-Str. 3, 72076 Tuebingen (Germany)], E-mail: stephan.miller@med.uni-tuebingen.de

    2009-01-15

    Objective: MR myocardial perfusion imaging (MRMPI) is an established technique for the evaluation of the hemodynamical relevance of coronary artery disease. Perfusion imaging at 3.0 T provides certain advantages compared to 1.5 T. Aim of this study was to evaluate myocardial MR perfusion imaging at 3.0 T. Materials and methods: Twelve patients with stable Angina pectoris and known or suspected coronary artery disease were examined at 3.0 T. Myocardial perfusion was assessed using a saturation recovery gradient echo 2D sequence (TR 1.9 ms, TE 1.0 ms, FA 12 deg.) with 0.05 mmol Gd-DTPA per kg body weight at stress during injection of 140 {mu}g adenosine/kg body weight/min and at rest in short axis orientation. Perfusion analysis was based on a least square fit of the signal/time curve (peak signal intensity, slope). Perfusion series were assessed by two independent observers. Reference for the presence of relevant coronary artery stenoses was invasive coronary angiography. Two experienced observers evaluated the coronary angiograms in biplane projections for the presence and grade of stenoses. Results were compared with the MR perfusion analysis. Results: All MR examinations could be safely performed and yielded high image quality. In eight patients stress-induced hypoperfusion was detected (stenosis >70% in coronary angiography). In four patients myocardial hypoperfusion was ruled out (stenosis <70%). The myocardial perfusion reserve index was significantly reduced in hypoperfused myocardium with 1.9 {+-} 1.6 compared to 2.5 {+-} 1.6 in regularly perfused myocardium (p < 0.05). In coronary angiography, eight patients were found to suffer from coronary artery disease, whereas in four patients coronary artery disease was ruled out. Conclusion: Our initial results show that MRMPI at 3.0 T provides reliably high-image quality and diagnostic accuracy.

  11. Quality assessment of a placental perfusion protocol

    DEFF Research Database (Denmark)

    Mathiesen, Line; Mose, Tina; Mørck, Thit Juul

    2010-01-01

    mlh(-1) from the fetal reservoir) when adding 2 (n=7) and 20mg (n=9) FITC-dextran/100ml fetal perfusion media. Success rate of the Copenhagen placental perfusions is provided in this study, including considerations and quality control parameters. Three checkpoints suggested to determine success rate...

  12. Regional Cerebral Perfusion in Progressive Supranuclear Palsy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Yong; Lee, Ki Hyeong; Yoon, Byung Woo; Lee, Sang Bok; Jeon, Beom S. [Samsung Medical Center, Seoul (Korea, Republic of); Lee, Kyung Han; Lee, Myung Chul [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1996-03-15

    Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p<0.05). There was no correlation between the severity of the motor abnormality and any of the regional cerebral perfusion indices (p>0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

  13. Computed Tomography (CT) Perfusion in Abdominal Cancer

    DEFF Research Database (Denmark)

    Hansen, Martin Lundsgaard; Norling, Rikke; Lauridsen, Carsten

    2013-01-01

    Computed Tomography (CT) Perfusion is an evolving method to visualize perfusion in organs and tissue. With the introduction of multidetector CT scanners, it is now possible to cover up to 16 cm in one rotation, and thereby making it possible to scan entire organs such as the liver with a fixed...

  14. Clinical application of cerebral dynamic perfusion studies

    International Nuclear Information System (INIS)

    DeLand, F.H.

    1975-01-01

    Radionuclide cerebral perfusion studies are assuming a far greater importance in the detection and differential diagnosis of cerebral lesions. Perfusion studies not only contribute to the differential diagnosis of lesions but in certain cases are the preferred methods by which more accurate clinical interpretations can be made. The characteristic blood flow of arterio-venous malformations readily differentiates this lesion from neoplasms. The decreased perfusion or absent perfusion observed in cerebral infarctions is diagnostic without concurrent evidence from static images. Changes in rates and direction of blood flow contribute fundamental information to the status of stenosis and vascular occlusion and, in addition, offer valuable information on the competency and routes of collateral circulation. The degree of cerebral perfusion after cerebral vascular accidents appears to be directly related to patient recovery, particularly muscular function. Cerebral perfusion adds a new parameter in the diagnosis of subdural haematomas and concussion and in the differentiation of obscuring radioactivity from superficial trauma. Although pictorial displays of perfusion blood flow will offer information in most cerebral vascular problems, the addition of computer analysis better defines temporal relationships of regional blood flow, quantitative changes in flow and the detection of the more subtle increases or decreases in cerebral blood flow. The status of radionuclide cerebral perfusion studies has taken on an importance making it the primary modality for the diagnosis of cerebral lesions. (author)

  15. Normothermic perfusion: a new paradigm for organ preservation.

    Science.gov (United States)

    Brockmann, Jens; Reddy, Srikanth; Coussios, Constantin; Pigott, David; Guirriero, Dino; Hughes, David; Morovat, Alireza; Roy, Debabrata; Winter, Lucy; Friend, Peter J

    2009-07-01

    Transplantation of organs retrieved after cardiac arrest could increase the donor organ supply. However, the combination of warm ischemia and cold preservation is highly detrimental to the reperfused organ. Our objective was to maintain physiological temperature and organ function during preservation and thereby alleviate this injury and allow successful transplantation. We have developed a liver perfusion device that maintains physiological temperature with provision of oxygen and nutrition. Reperfusion experiments suggested that this allows recovery of ischemic damage. In a pig liver transplant model, we compared the outcome following either conventional cold preservation or warm preservation. Preservation periods of 5 and 20 hours and durations of warm ischemia of 40 and 60 minutes were tested. After 20 hours preservation without warm ischemia, post-transplant survival was improved (27%-86%, P = 0.026), with corresponding differences in transaminase levels and histological analysis. With the addition of 40 minutes warm ischemia, the differences were even more marked (cold vs. warm groups 0% vs. 83%, P = 0.001). However, with 60 minutes warm ischemia and 20 hours preservation, there were no survivors. Analysis of hemodynamic and liver function data during perfusion showed several factors to be predictive of posttransplant survival, including bile production, base excess, portal vein flow, and hepatocellular enzymes. Organ preservation by warm perfusion, maintaining physiological pressure and flow parameters, has enabled prolonged preservation and successful transplantation of both normal livers and those with substantial ischemic damage. This technique has the potential to address the shortage of organs for transplantation.

  16. Pequi fruit (Caryocar brasiliense Camb.) pulp oil reduces exercise-induced inflammatory markers and blood pressure of male and female runners.

    Science.gov (United States)

    Miranda-Vilela, Ana L; Pereira, Luiz C S; Gonçalves, Carlos A; Grisolia, Cesar K

    2009-12-01

    The objective of this study was to investigate the anti-inflammatory properties of pequi (Caryocar brasiliense) fruit oil and its effects on the postprandial lipidemia and arterial blood pressure of male and female athletes. These athletes were evaluated after races in the same environment and under the same type, intensity, and length of weekly training conditions, both before and after ingestion of 400 mg pequi oil capsules for 14 days. Pequi fruit contains several antioxidants, and its oil has been associated with anti-inflammatory properties in other pequi species. Because the oil of pequi is mostly composed of oleic and palmitic fatty acids, the oil may alter the ratio of triglyceride to cholesterol in postprandial lipidemia. Epidemiologic studies suggest that an increased intake of monounsaturated fatty acids (such as oleic acid) is inversely related to blood pressure. Thus, we hypothesize that pequi oil could reduce exercise-induced inflammation and blood pressure, and modulate postprandial lipidemia in runners. To test this hypothesis, arterial blood pressures were checked before races; blood samples were taken after the races and submitted for analysis of leukocytes and platelets analysis, high-sensitivity C-reactive protein values, and postprandial lipids. Pequi oil resulted in anti-inflammatory effects and reduced the total cholesterol and low-density lipoprotein in the age group older than 45 years, mainly for men. The results showed a general trend for reduced arterial pressure, suggesting that pequi oil may have a hypotensive effect. However, this finding needs additional investigation. Thus, pequi oil, besides possessing many nutritional properties, may be a good candidate supplement for athletes.

  17. Validation of a methodology to develop a test facility in reduced scale related to boron dispersion in a pressurizer of an iPWR

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, Samira R.V.; Lira, Carlos A.B.O.; Lapa, Celso M.F.; Lima, Fernando R.A.; Bezerra, Jair L.; Silva, Mário A.B., E-mail: cabol@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Centro de Tecnologia e Geociências. Departamento de Energia Nuclear; Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil); Centro Regional de Ciências Nucleares do Nordeste (CRCN/CNEN-PE), Recife, PE (Brazil)

    2017-11-01

    The conception and the project of a 1:200 reduced scale test facility have been developed in earlier researches. Such a facility aims to investigate boron homogenization process inside the pressurizer of an iPWR (integral PWR) by considering water mixing from this component with that coming from the reactor core. For this kind of reactor, the pressurizer is located at the top of the pressure vessel demanding the need of identifying the proper mechanisms in order to warrant an adequate homogenization for the water mixture. Once the installation of the experimental setup was concluded, its behavior has been analyzed by considering the concentration of a tracer diluted in the circulation water, whose measurements were obtained at the pressurizer outlet orifices. Two experiments representing boration(boron concentration increase)/deboration(boron concentration decrease) scenarios have been accomplished. Sample acquisition was carried out for every ten minutes during a total time equal to 180 minutes. Results showed that the combination of Fractional Scaling Analysis with local Froude number consisted of an appropriate methodology to provide the reduced scale test facility parameters, inasmuch the measured concentrations from the experiments reproduced the theoretical behavior with sufficient accuracy. (author)

  18. Validation of a methodology to develop a test facility in reduced scale related to boron dispersion in a pressurizer of an iPWR

    International Nuclear Information System (INIS)

    Nascimento, Samira R.V.; Lira, Carlos A.B.O.; Lapa, Celso M.F.; Lima, Fernando R.A.; Bezerra, Jair L.; Silva, Mário A.B.

    2017-01-01

    The conception and the project of a 1:200 reduced scale test facility have been developed in earlier researches. Such a facility aims to investigate boron homogenization process inside the pressurizer of an iPWR (integral PWR) by considering water mixing from this component with that coming from the reactor core. For this kind of reactor, the pressurizer is located at the top of the pressure vessel demanding the need of identifying the proper mechanisms in order to warrant an adequate homogenization for the water mixture. Once the installation of the experimental setup was concluded, its behavior has been analyzed by considering the concentration of a tracer diluted in the circulation water, whose measurements were obtained at the pressurizer outlet orifices. Two experiments representing boration(boron concentration increase)/deboration(boron concentration decrease) scenarios have been accomplished. Sample acquisition was carried out for every ten minutes during a total time equal to 180 minutes. Results showed that the combination of Fractional Scaling Analysis with local Froude number consisted of an appropriate methodology to provide the reduced scale test facility parameters, inasmuch the measured concentrations from the experiments reproduced the theoretical behavior with sufficient accuracy. (author)

  19. Methodology for ventilation/perfusion SPECT

    DEFF Research Database (Denmark)

    Bajc, Marika; Neilly, Brian; Miniati, Massimo

    2010-01-01

    radiolabeled liquid aerosols are not restricted to the presence of obstructive lung disease. Radiolabeled macroaggregated human albumin is the imaging agent of choice for perfusion scintigraphy. An optimal combination of nuclide activities and acquisition times for ventilation and perfusion, collimators......Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas over......, and imaging matrix yields an adequate V/Q SPECT study in approximately 20 minutes of imaging time. The recommended protocol based on the patient remaining in an unchanged position during the initial ventilation study and the perfusion study allows presentation of matching ventilation and perfusion slices...

  20. Assessment of right liver graft perfusion effectiveness between one and two-catheter infusion methods.

    Science.gov (United States)

    Jung, Bo-Hyun; Hwang, Shin; Ha, Tae-Yong; Song, Gi-Won; Jung, Dong-Hwan; Kim, Ki-Hun; Ahn, Chul-Soo; Moon, Deok-Bog; Park, Gil-Chun; Kang, Sung-Hwa; Yoon, Young-In; Lee, Sung-Gyu

    2014-05-01

    Conventional graft perfusion method using one small-caliber catheter takes a relatively long time for right liver graft perfusion, thus some modification is needed. In this study, we intended to assess the effectiveness of right liver graft perfusion methods through comparison of different infusion catheters. The study consisted of two parts including one bench experiment to obtain data of hydraulic infusion and one clinical trial of 40 cases on graft perfusion with one- versus two-catheter infusion methods. These two graft infusion methods were compared in terms of the perfusion time and washing-out efficiency. At bench experiment, the infusion flow rate and infusion pressure were 3.3 ml/sec and 1.9 cmH20 in one blood transfusion catheter group, and 11.7 ml/sec and 3.1 cmH20 in single transurethral resection of prostate irrigation catheter group, and 6.6 ml/sec and 2.0 cmH20 in two blood transfusion catheters group, respectively. In clinical trial with 40 right liver grafts, two-catheter group had a shorter graft portal perfusion time for the first 2 L of histidine-tryptophan-ketoglutarate (HTK) solution than the conventional one-catheter group (375±25 seconds vs. 662±34 seconds; p=0.001) and a lower rate of incomplete blood washing-out after the initial 2 L portal perfusion (40% vs. 85%; p=0.03). The two-catheter infusion method appears to be more effective than the conventional one-catheter infusion method for right liver graft perfusion at the back table. Large size of right liver grafts seems to be its good indication.

  1. Effect of a DC external electric field on the properties of a nonuniform microwave discharge in hydrogen at reduced pressures

    Energy Technology Data Exchange (ETDEWEB)

    Lebedev, Yu. A., E-mail: lebedev@ips.ac.ru; Krashevskaya, G. V.; Tatarinov, A. V.; Titov, A. Yu.; Epshtein, I. L. [Russian Academy of Sciences, Topchiev Institute of Petrochemical Synthesis (Russian Federation)

    2017-01-15

    The effect of a dc external electrical field on the properties of a highly nonuniform electrode microwave discharge in hydrogen at a pressure of 1 Torr was studied using optical emission spectroscopy and selfconsistent two-dimensional simulations. It is shown that the negative voltage applied to the antenna electrode with respect to the grounded chamber increases the discharge radiation intensity, while the positive voltage does not affect the discharge properties. The simulation results agree well with the experimental data.

  2. Effect of a DC external electric field on the properties of a nonuniform microwave discharge in hydrogen at reduced pressures

    International Nuclear Information System (INIS)

    Lebedev, Yu. A.; Krashevskaya, G. V.; Tatarinov, A. V.; Titov, A. Yu.; Epshtein, I. L.

    2017-01-01

    The effect of a dc external electrical field on the properties of a highly nonuniform electrode microwave discharge in hydrogen at a pressure of 1 Torr was studied using optical emission spectroscopy and selfconsistent two-dimensional simulations. It is shown that the negative voltage applied to the antenna electrode with respect to the grounded chamber increases the discharge radiation intensity, while the positive voltage does not affect the discharge properties. The simulation results agree well with the experimental data.

  3. Gradual reintroduction of oxygen reduces reperfusion injury in cat stomach

    International Nuclear Information System (INIS)

    Perry, M.A.; Wadhwa, S.S.

    1988-01-01

    Recent studies have shown that oxygen-derived free radicals are responsible for a major portion of ischemia-reperfusion injury in the stomach. The oxygen radicals are produced during perfusion when oxygen delivery to the tissue increases. In the present study the authors investigate the effect on mucosal injury of regulating the rate of reintroduction of oxygen to the stomach after ischemia. Local gastric ischemia was achieved by reducing celiac artery pressure to 30 mmHg for 1 h. Ischemic injury was assessed by measuring the loss of 51 Cr-labeled red blood cells across the gastric mucosa. Mucosal blood loss was negligible before and during the ischemia period but increased during reperfusion. When blood flow to the stomach was gradually returned to normal after ischemia, the mucosal blood loss was reduced. If the stomach was vascularly perfused with low Po 2 blood for 1 h after ischemia before being returned to normal arterial perfusion, the mucosal blood loss was also reduced. When the stomach was made hypoxemic for 1 h rather than ischemic by perfusing the vasculature with low Po 2 blood then reperfused with normoxic blood, there was very little mucosal bleeding. The data indicate that gastric mucosal bleeding after ischemia is reduced if the tissue is returned slowly to a normal Po 2 . These findings support the concept that reperfusion injury is due largely to the production of oxygen radicals. The low level of injury produced by hypoxemia indicates that hypoxia per se makes only a minor contribution to reperfusion injury in the stomach

  4. Brain Perfusion Changes in Intracerebral Hemorrhage

    International Nuclear Information System (INIS)

    Mititelu, R.; Mazilu, C.; Ghita, S.; Rimbu, A.; Marinescu, G.; Codorean, I.; Bajenaru, O.

    2006-01-01

    Full text: Purpose: Despite the latest advances in medical treatment and neuro critical care, patients suffering spontaneous intracerebral hemorrhage (SICH) still have a very poor prognosis, with a greater mortality and larger neurological deficits at the survivors than for ischemic stroke. Many authors have shown that there are many mechanisms involved in the pathology of SICH: edema, ischemia, inflammation, apoptosis. All of these factors are affecting brain tissue surrounding hematoma and are responsible of the progressive neurological deterioration; most of these damages are not revealed by anatomical imaging techniques. The aim of our study was to asses the role of brain perfusion SPECT in demonstrating perfusion changes in SICH patients. Method: 17 SICH pts were studied. All pts underwent same day CT and brain SPECT with 99mTcHMPAO, 24h-5d from onset of stroke. Results: 14/17 pts showed a larger perfusion defect than expected after CT. In 2 pts hematoma diameter was comparable on CT and SPECT; 1pt had quasinormal aspect of SPECT study. In pts with larger defects, SPECT revealed a large cold spot with similar size compared with CT, and a surrounding hypo perfused area. 6/17 pts revealed cortical hyper perfusion adjacent to hypo perfused area and corresponding to a normal-appearing brain tissue on CT. In 3 pts we found crossed cerebellar diaskisis.In 2 pts we found cortical hypo perfused area in the contralateral cortex, with normal appearing brain tissue on CT. Conclusions: Brain perfusion SPECT revealed different types of perfusion changes in the brain tissue surrounding hematoma. These areas contain viable brain tissue that may be a target for future ne uroprotective strategies. Further studies are definitely required to demonstrate prognostic significance of these changes, but we can conclude that brain perfusion SPECT can play an important role in SICH, by early demonstrating functional changes responsible of clinical deterioration, thus allowing prompt

  5. Correlation of the myocardial perfusion corrected by attenuation with the coronariography. Preliminary results

    International Nuclear Information System (INIS)

    Garcia C, S.E.; Garcia O, R.

    2005-01-01

    The attenuation that suffers the radiation in the soft tissues of the hinders the appropriate interpretation of the myocardial perfusion studies, for what have been implemented attenuation correction systems to reduce the attenuation for soft tissues and to provide myocardial perfusion images more accurate in the diagnosis of coronary illness. The objective was to evaluate the utility of an attenuation correction system (with source of Gadolinium 153) to minimize the devices that look like true defects of myocardial perfusion, caused by soft tissues (mammary tissue, thoracic wall, abdomen, left hemi diaphragm), and to compare those interpretations of the studies with the interpretations of the corresponding coronariographies. The method consists of 95 electronic files which were revised with the concept of heart catheterization, being identified 20 patients from the masculine sex to those that underwent coronariography among May 1999 and December 2002, and that they had study of myocardial perfusion in a maximum period of 3 months foresaw to the invasive procedure. (Author)

  6. Simulation evaluation of quantitative myocardial perfusion assessment from cardiac CT

    Science.gov (United States)

    Bindschadler, Michael; Modgil, Dimple; Branch, Kelley R.; La Riviere, Patrick J.; Alessio, Adam M.

    2014-03-01

    Contrast enhancement on cardiac CT provides valuable information about myocardial perfusion and methods have been proposed to assess perfusion with static and dynamic acquisitions. There is a lack of knowledge and consensus on the appropriate approach to ensure 1) sufficient diagnostic accuracy for clinical decisions and 2) low radiation doses for patient safety. This work developed a thorough dynamic CT simulation and several accepted blood flow estimation techniques to evaluate the performance of perfusion assessment across a range of acquisition and estimation scenarios. Cardiac CT acquisitions were simulated for a range of flow states (Flow = 0.5, 1, 2, 3 ml/g/min, cardiac output = 3,5,8 L/min). CT acquisitions were simulated with a validated CT simulator incorporating polyenergetic data acquisition and realistic x-ray flux levels for dynamic acquisitions with a range of scenarios including 1, 2, 3 sec sampling for 30 sec with 25, 70, 140 mAs. Images were generated using conventional image reconstruction with additional image-based beam hardening correction to account for iodine content. Time attenuation curves were extracted for multiple regions around the myocardium and used to estimate flow. In total, 2,700 independent realizations of dynamic sequences were generated and multiple MBF estimation methods were applied to each of these. Evaluation of quantitative kinetic modeling yielded blood flow estimates with an root mean square error (RMSE) of ~0.6 ml/g/min averaged across multiple scenarios. Semi-quantitative modeling and qualitative static imaging resulted in significantly more error (RMSE = ~1.2 and ~1.2 ml/min/g respectively). For quantitative methods, dose reduction through reduced temporal sampling or reduced tube current had comparable impact on the MBF estimate fidelity. On average, half dose acquisitions increased the RMSE of estimates by only 18% suggesting that substantial dose reductions can be employed in the context of quantitative myocardial

  7. Effect of beam hardening on transmural myocardial perfusion quantification in myocardial CT imaging

    Science.gov (United States)

    Fahmi, Rachid; Eck, Brendan L.; Levi, Jacob; Fares, Anas; Wu, Hao; Vembar, Mani; Dhanantwari, Amar; Bezerra, Hiram G.; Wilson, David L.

    2016-03-01

    The detection of subendocardial ischemia exhibiting an abnormal transmural perfusion gradient (TPG) may help identify ischemic conditions due to micro-vascular dysfunction. We evaluated the effect of beam hardening (BH) artifacts on TPG quantification using myocardial CT perfusion (CTP). We used a prototype spectral detector CT scanner (Philips Healthcare) to acquire dynamic myocardial CTP scans in a porcine ischemia model with partial occlusion of the left anterior descending (LAD) coronary artery guided by pressure wire-derived fractional flow reserve (FFR) measurements. Conventional 120 kVp and 70 keV projection-based mono-energetic images were reconstructed from the same projection data and used to compute myocardial blood flow (MBF) using the Johnson-Wilson model. Under moderate LAD occlusion (FFR~0.7), we used three 5 mm short axis slices and divided the myocardium into three LAD segments and three remote segments. For each slice and each segment, we characterized TPG as the mean "endo-to-epi" transmural flow ratio (TFR). BH-induced hypoenhancement on the ischemic anterior wall at 120 kVp resulted in significantly lower mean TFR value as compared to the 70 keV TFR value (0.29+/-0.01 vs. 0.55+/-0.01 pvalues on segments moderately affected or unaffected by BH. In the entire ischemic LAD territory, 120 kVp mean endocardial flow was significantly reduced as compared to mean epicardial flow (15.80+/-10.98 vs. 40.85+/-23.44 ml/min/100g; p<1e-04). At 70 keV, BH was effectively minimized resulting in mean endocardial MBF of 40.85+/-15.3407 ml/min/100g vs. 74.09+/-5.07 ml/min/100g (p=0.0054) in the epicardium. We also found that BH artifact in the conventional 120 kVp images resulted in falsely reduced MBF measurements even under non-ischemic conditions.

  8. CT perfusion imaging of the liver and the spleen in patients with cirrhosis: Is there a correlation between perfusion and portal venous hypertension?

    Science.gov (United States)

    Talakić, Emina; Schaffellner, Silvia; Kniepeiss, Daniela; Mueller, Helmut; Stauber, Rudolf; Quehenberger, Franz; Schoellnast, Helmut

    2017-10-01

    To correlate hepatic and splenic CT perfusion parameters with hepatic venous pressure gradient (HVPG) measurements in patients with cirrhosis. Twenty-one patients with cirrhosis (males, 17; females, 4; mean ± SD age, 57 ± 7 years) underwent hepatic and splenic perfusion CT on a 320-detector row volume scanner as well as invasive measurement of HVPG. Different CT perfusion algorithms (maximum slope analysis and Patlak plot) were used to measure hepatic arterial flow (HAF), portal venous flow (PVF), hepatic perfusion index (HPI), splenic arterial flow (SAF), splenic blood volume (SBV) and splenic clearance (SCL). Hepatic and splenic perfusion parameters were correlated with HVPG, and sensitivity and specificity for detection of severe portal hypertension (≥12 mmHg) were calculated. The Spearman correlation coefficient was -0.53 (p portal hypertension. • SAF and SCL are statistically significantly correlated with HVPG • SCL showed stronger correlation with HVPG than SAF • 125 ml/min/100 ml SCL-cut-off yielded 94 % sensitivity, 100 % specificity for severe PH • HAF, PVF and HPI showed no statistically significant correlation with HVPG.

  9. Assessment of foot perfusion in patients with a diabetic foot ulcer.

    Science.gov (United States)

    Forsythe, Rachael O; Hinchliffe, Robert J

    2016-01-01

    Assessment of foot perfusion is a vital step in the management of patients with diabetic foot ulceration, in order to understand the risk of amputation and likelihood of wound healing. Underlying peripheral artery disease is a common finding in patients with foot ulceration and is associated with poor outcomes. Assessment of foot perfusion should therefore focus on identifying the presence of peripheral artery disease and to subsequently estimate the effect this may have on wound healing. Assessment of perfusion can be difficult because of the often complex, diffuse and distal nature of peripheral artery disease in patients with diabetes, as well as poor collateralisation and heavy vascular calcification. Conventional methods of assessing tissue perfusion in the peripheral circulation may be unreliable in patients with diabetes, and it may therefore be difficult to determine the extent to which poor perfusion contributes to foot ulceration. Anatomical data obtained on cross-sectional imaging is important but must be combined with measurements of tissue perfusion (such as transcutaneous oxygen tension) in order to understand the global and regional perfusion deficit present in a patient with diabetic foot ulceration. Ankle-brachial pressure index is routinely used to screen for peripheral artery disease, but its use in patients with diabetes is limited in the presence of neuropathy and medial arterial calcification. Toe pressure index may be more useful because of the relative sparing of pedal arteries from medial calcification but may not always be possible in patients with ulceration. Fluorescence angiography is a non-invasive technique that can provide rapid quantitative information about regional tissue perfusion; capillaroscopy, iontophoresis and hyperspectral imaging may also be useful in assessing physiological perfusion but are not widely available. There may be a future role for specialized perfusion imaging of these patients, including magnetic resonance

  10. Simultaneous maximal exercise radionuclide angiography and thallium stress perfusion imaging

    International Nuclear Information System (INIS)

    Narahara, K.A.; Mena, I.; Maublant, J.C.; Brizendine, M.; Criley, J.M.

    1984-01-01

    Gold-195m is a new ultra-short-lived radionuclide that can be used for cardiac studies. Accurate, reproducible ejection fraction and ventricular wall motion studies can be obtained from first-transit angiography using commercially available imaging and image-processing equipment. The short half-life of gold-195m (30.5 seconds) makes simultaneous dual isotope imaging possible and substantially reduces the radiation exposure from the isotope angiography. The feasibility and possible benefits of performing dual radionuclide studies were evaluated during a single exercise stress test in 24 subjects with known coronary artery disease (CAD) and in 20 normal volunteers. High-quality first-transit angiograms were obtained in all subjects. An 83% sensitivity and 95% specificity for detecting CAD with thallium-201 imaging was noted in this investigation, suggesting that its diagnostic accuracy was not altered by simultaneous dual isotone imaging. When segmental left ventricular (LV) wall motion was compared with thallium-201 perfusion imaging, divergent results were noted in 15 of 44 subjects. An analysis of the ejection fraction (EF) results at rest and stress provided additional information that could be useful in assessing the clinical significance of such differences in segmental wall motion and perfusion. Simultaneous dual isotope imaging appears to be appropriate for situations in which both LV perfusion and function require evaluation. The use of gold-195m allows such information to be obtained from a single exercise test and can thereby reduce the cost and time required for noninvasive evaluations of patients for CAD

  11. Pressure Ulcers

    OpenAIRE

    Monfre, Jill M.

    2016-01-01

    Unrelieved pressure or friction of the skin, particularly over bony prominences, can lead to pressure ulcers, which affect up to one third of people in hospitals or community care, and one fifth of nursing home residents. Pressure ulcers are more likely in people with reduced mobility and poor skin condition, such as older people or those with vascular disease.

  12. A Technique to Perfuse Cadavers that Extends the Useful Life of Fresh Tissues: The Duke Experience

    Science.gov (United States)

    Messmer, Caroline; Kellogg, Ryan T.; Zhang, Yixin; Baiak, Andresa; Leiweke, Clinton; Marcus, Jeffrey R.; Levin, L. Scott; Zenn, Michael R.; Erdmann, Detlev

    2010-01-01

    The demand for laboratory-based teaching and training is increasing worldwide as medical training and education confront the pressures of shorter training time and rising costs. This article presents a cost-effective perfusion technique that extends the useful life of fresh tissue. Refrigerated cadavers are preserved in their natural state for up…

  13. Perfusion magnetic resonance imaging in pediatric brain tumors

    Energy Technology Data Exchange (ETDEWEB)

    Dallery, F.; Michel, D.; Constans, J.M.; Gondry-Jouet, C. [University Hospital, Department of Radiology, Amiens (France); Bouzerar, R.; Promelle, V.; Baledent, O. [University Hospital, Department of Imaging and Biophysics, Amiens (France); Attencourt, C. [University Hospital, Departement of Pathology, Amiens (France); Peltier, J. [University Hospital, Departement of Neurosurgery, Amiens (France)

    2017-11-15

    The use of DSC-MR imaging in pediatric neuroradiology is gradually growing. However, the number of studies listed in the literature remains limited. We propose to assess the perfusion and permeability parameters in pediatric brain tumor grading. Thirty children with a brain tumor having benefited from a DSC-MR perfusion sequence have been retrospectively explored. Relative CBF and CBV were computed on the ROI with the largest lesion coverage. Assessment of the lesion's permeability was also performed through the semi-quantitative PSR parameter and the K2 model-based parameter on the whole-lesion ROI and a reduced ROI drawn on the permeability maps. A statistical comparison of high- and low-grade groups (HG, LG) as well as a ROC analysis was performed on the histogram-based parameters. Our results showed a statistically significant difference between LG and HG groups for mean rCBV (p < 10{sup -3}), rCBF (p < 10{sup -3}), and for PSR (p = 0.03) but not for the K2 factor (p = 0.5). However, the ratio K2/PSR was shown to be a strong discriminating factor between the two groups of lesions (p < 10{sup -3}). For rCBV and rCBF indicators, high values of ROC AUC were obtained (> 0.9) and mean value thresholds were observed at 1.07 and 1.03, respectively. For K2/PSR in the reduced area, AUC was also superior to 0.9. The implementation of a dynamic T2* perfusion sequence provided reliable results using an objective whole-lesion ROI. Perfusion parameters as well as a new permeability indicator could efficiently discriminate high-grade from low-grade lesions in the pediatric population. (orig.)

  14. Fluctuation characteristics of arc voltage and jet flow in a non-transferred dc plasma generated at reduced pressure

    International Nuclear Information System (INIS)

    Pan, W X; Guo, Z Y; Meng, X; Huang, H J; Wu, C K

    2009-01-01

    A torch with a set of inter-electrode inserts between the cathode and the anode/nozzle with a wide nozzle exit was designed to generate plasma jets at chamber pressures of 500-10 000 Pa. The variation of the arc voltage was examined with the change in working parameters such as gas flow rate and chamber pressure. The fluctuation in the arc voltage was recorded with an oscilloscope, and the plasma jet fluctuation near the torch exit was observed with a high-speed video camera and detected with a double-electrostatic probe. Results show that the 300 Hz wave originated from the tri-phase rectified power supply was always detected under all generating conditions. Helmholtz oscillations over 3000 Hz was detected superposed on the 300 Hz wave at gas flow rates higher than 8.8 slm with a peak to valley amplitude lower than 5% of the average voltage value. No appreciable voltage fluctuation caused by the irregular arc root movement is detected, and mechanisms for the arc voltage and jet flow fluctuations are discussed.

  15. Paradoxical perfusion metrics of high-grade gliomas with an oligodendroglioma component: quantitative analysis of dynamic susceptibility contrast perfusion MR imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sunwoo, Leonard; Park, Sun-Won [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul Metropolitan Government - Seoul National University Boramae Medical Center, Department of Radiology, Seoul (Korea, Republic of); Choi, Seung Hong [Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Seoul National University, Center for Nanoparticle Research, Institute for Basic Science, and School of Chemical and Biological Engineering, Seoul (Korea, Republic of); Yoo, Roh-Eul; Kang, Koung Mi; Yun, Tae Jin; Kim, Ji-hoon; Sohn, Chul-Ho [Seoul National University College of Medicine, Department of Radiology, Seoul (Korea, Republic of); Seoul National University Hospital, Department of Radiology, Seoul (Korea, Republic of); Kim, Tae Min; Lee, Se-Hoon [Seoul National University Hospital, Department of Internal Medicine, Seoul (Korea, Republic of); Park, Chul-Kee [Seoul National University Hospital, Department of Neurosurgery, Seoul (Korea, Republic of); Won, Jae-Kyung; Park, Sung-Hye [Seoul National University Hospital, Department of Pathology, Seoul (Korea, Republic of); Kim, Il Han [Seoul National University Hospital, Department of Radiation Oncology, Seoul (Korea, Republic of)

    2015-11-15

    The aim of this study is to investigate perfusion characteristics of glioblastoma with an oligodendroglioma component (GBMO) compared with conventional glioblastoma (GBM) using dynamic susceptibility contrast (DSC) perfusion magnetic resonance (MR) imaging and microvessel density (MVD). The study was approved by the institutional review board. Newly diagnosed high-grade glioma patients were enrolled (n = 72; 20 GBMs, 14 GBMOs, 19 anaplastic astrocytomas (AAs), 13 anaplastic oligodendrogliomas (AOs), and six anaplastic oligoastrocytomas (AOAs)). All participants underwent preoperative MR imaging including DSC perfusion MR imaging. Normalized cerebral blood volume (nCBV) values were analyzed using a histogram approach. Histogram parameters were subsequently compared across each tumor subtype and grade. MVD was quantified by immunohistochemistry staining and correlated with perfusion parameters. Progression-free survival (PFS) was assessed according to the tumor subtype. GBMO displayed significantly reduced nCBV values compared with GBM, whereas grade III tumors with oligodendroglial components (AO and AOA) exhibited significantly increased nCBV values compared with AA (p < 0.001). MVD analyses revealed the same pattern as nCBV results. In addition, a positive correlation between MVD and nCBV values was noted (r = 0.633, p < 0.001). Patients with oligodendroglial tumors exhibited significantly increased PFS compared with patients with pure astrocytomas in each grade. In contrast to grade III tumors, the presence of oligodendroglial components in grade IV tumors resulted in paradoxically reduced perfusion metrics and MVD. In addition, patients with GBMO exhibited a better clinical outcome compared with patients with GBM. (orig.)

  16. Vasoactive mediators and splanchnic perfusion.

    Science.gov (United States)

    Reilly, P M; Bulkley, G B

    1993-02-01

    To provide an overview of the splanchnic hemodynamic response to circulatory shock. Previous studies performed in our own laboratory, as well as a computer-assisted search of the English language literature (MEDLINE, 1966 to 1991), followed by a selective review of pertinent articles. Studies were selected that demonstrated relevance to the splanchnic hemodynamic response to circulatory shock, either by investigating the pathophysiology or documenting the sequelae. Article selection included clinical studies as well as studies in appropriate animal models. Pertinent data were abstracted from the cited articles. The splanchnic hemodynamic response to circulatory shock is characterized by a selective vasoconstriction of the mesenteric vasculature mediated largely by the renin-angiotensin axis. This vasospasm, while providing a natural selective advantage to the organism in mild-to-moderate shock (preserving relative perfusion of the heart, kidneys, and brain), may, in more severe shock, cause consequent loss of the gut epithelial barrier, or even hemorrhagic gastritis, ischemic colitis, or ischemic hepatitis. From a physiologic standpoint, nonpulsatile cardiopulmonary bypass, a controlled form of circulatory shock, has been found experimentally to significantly increase circulating levels of angiotensin II, the hormone responsible for this selective splanchnic vasoconstriction. While angiotensin II has been viewed primarily as the mediator responsible for the increased total vascular resistance seen during (and after) cardiopulmonary bypass, it may also cause the disproportionate decrease in mesenteric perfusion, as measured in human subjects by intraluminal gastric tonometry and galactose clearance by the liver, as well as the consequent development of the multiple organ failure syndrome seen in 1% to 5% of patients after cardiac surgery.

  17. Regional Cerebral Perfusion in Progressive Supranuclear Palsy

    International Nuclear Information System (INIS)

    Lee, Won Yong; Lee, Ki Hyeong; Yoon, Byung Woo; Lee, Sang Bok; Jeon, Beom S.; Lee, Kyung Han; Lee, Myung Chul

    1996-01-01

    Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p 0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

  18. Computerized analysis of brain perfusion parameter images

    International Nuclear Information System (INIS)

    Turowski, B.; Haenggi, D.; Wittsack, H.J.; Beck, A.; Aurich, V.

    2007-01-01

    Purpose: The development of a computerized method which allows a direct quantitative comparison of perfusion parameters. The display should allow a clear direct comparison of brain perfusion parameters in different vascular territories and over the course of time. The analysis is intended to be the basis for further evaluation of cerebral vasospasm after subarachnoid hemorrhage (SAH). The method should permit early diagnosis of cerebral vasospasm. Materials and Methods: The Angiotux 2D-ECCET software was developed with a close cooperation between computer scientists and clinicians. Starting from parameter images of brain perfusion, the cortex was marked, segmented and assigned to definite vascular territories. The underlying values were averages for each segment and were displayed in a graph. If a follow-up was available, the mean values of the perfusion parameters were displayed in relation to time. The method was developed under consideration of CT perfusion values but is applicable for other methods of perfusion imaging. Results: Computerized analysis of brain perfusion parameter images allows an immediate comparison of these parameters and follow-up of mean values in a clear and concise manner. Values are related to definite vascular territories. The tabular output facilitates further statistic evaluations. The computerized analysis is precisely reproducible, i. e., repetitions result in exactly the same output. (orig.)

  19. Biofeedback effectiveness to reduce upper limb muscle activity during computer work is muscle specific and time pressure dependent

    DEFF Research Database (Denmark)

    Vedsted, Pernille; Søgaard, Karen; Blangsted, Anne Katrine

    2011-01-01

    trapezius (TRA) can reduce bilateral TRA activity but not extensor digitorum communis (EDC) activity; (2) biofeedback from EDC can reduce activity in EDC but not in TRA; (3) biofeedback is more effective in no time constraint than in the time constraint working condition. Eleven healthy women performed......Continuous electromyographic (EMG) activity level is considered a risk factor in developing muscle disorders. EMG biofeedback is known to be useful in reducing EMG activity in working muscles during computer work. The purpose was to test the following hypotheses: (1) unilateral biofeedback from...... computer work during two different working conditions (time constraint/no time constraint) while receiving biofeedback. Biofeedback was given from right TRA or EDC through two modes (visual/auditory) by the use of EMG or mechanomyography as biofeedback source. During control sessions (no biofeedback), EMG...

  20. Concomitant administration of nitrous oxide and remifentanil reduces oral tissue blood flow without decreasing blood pressure during sevoflurane anesthesia in rabbits.

    Science.gov (United States)

    Kasahara, Masataka; Ichinohe, Tatsuya; Okamoto, Sota; Okada, Reina; Kanbe, Hiroaki; Matsuura, Nobuyuki

    2015-06-01

    To determine whether continuous administration of nitrous oxide and remifentanil—either alone or together—alters blood flow in oral tissues during sevoflurane anesthesia. Eight male tracheotomized Japanese white rabbits were anesthetized with sevoflurane under mechanical ventilation. Heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean arterial pressure (MAP), common carotid arterial blood flow (CCBF), tongue mucosal blood flow (TMBF), mandibular bone marrow blood flow (BBF), masseter muscle blood flow (MBF), upper alveolar tissue blood flow (UBF), and lower alveolar tissue blood flow (LBF) were recorded in the absence of all test agents and after administration of the test agents (50 % nitrous oxide, 0.4 μg/kg/min remifentanil, and their combination) for 20 min. Nitrous oxide increased SBP, DBP, MAP, CCBF, BBF, MBF, UBF, and LBF relative to baseline values but did not affect HR or TMBF. Remifentanil decreased all hemodynamic variables except DBP. Combined administration of nitrous oxide and remifentanil recovered SBP, DBP, MAP, and CCBF to baseline levels, but HR and oral tissue blood flow remained lower than control values. Our findings suggest that concomitant administration of nitrous oxide and remifentanil reduces blood flow in oral tissues without decreasing blood pressure during sevoflurane anesthesia in rabbits.

  1. Dynamic contrast enhanced MRI for perfusion quantification

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke

    2002-01-01

    Magnetic resonance imaging, during bolus passage of a paramagnetic contrast agent, is used world-wide to obtain parameters that reflect the pathological state of tissue. Abnormal perfusion occurs in diseases such as stoke and tumour. Consequently, perfusion quantication could have signi cant...... clinical value both in diagnosis and treatment of such pathologies. One approach for perfusion quanti cation involves using the contrast mechanism that a ects the transverse relaxation rates of the magnetization, R2 or R 2 , since this provides the most pronounced effect. However, the linearity between...

  2. REDUCING REJECTION/REWORK IN PRESSURE DIE CASTING PROCESS BY APPLICATION OF DMAIC METHODOLOGY OF SIX SIGMA

    Directory of Open Access Journals (Sweden)

    Javedhusen Malek

    2015-12-01

    Full Text Available In today's ever-changing customer driven market, industries are needed to improve their products and processes to satisfy customer requirements. The Six Sigma approach has set a new paradigm of business excellence. Six Sigma as a process driven improvement methodology has been adopted successfully by many industries. From the review of various literatures, it is revealed that Six Sigma is well adopted in large scale enterprise but having less evidence of adoption in Indian SMEs. This paper is focused on providing path to Indian SMEs for initiating Six Sigma approach in their industries. The paper discusses the real life case where Six Sigma has been successfully applied at one of the Indian small-scale unit to improve rejection/rework rate in manufacturing products by pressure die casting process. This paper describes phase wise application of all the phases of define-measure-analyse-improve-control (DMAIC which also shows impact of Six Sigma in quality improvement.

  3. Chronic hypoxia increases arterial blood pressure and reduces adenosine and ATP induced vasodilatation in skeletal muscle in healthy humans

    DEFF Research Database (Denmark)

    Calbet, J A L; Boushel, Robert Christopher; Robach, P

    2014-01-01

    into the femoral artery at sea level and then after 8-12 days of residence at 4559 m above sea level. At sea level, the infusions were carried out while the subjects breathed room air, acute hypoxia (FI O2 = 0.11) and hyperoxia (FI O2 = 1); and at altitude (FI O2 = 0.21 and 1). Skeletal muscle P2Y2 receptor...... protein expression was determined in muscle biopsies after 4 weeks at 3454 m by Western blot. RESULTS: At altitude, mean arterial blood pressure was 13% higher (91 ± 2 vs. 102 ± 3 mmHg, P sea level and was unaltered by hyperoxic breathing. Baseline leg vascular conductance was 25% lower...... at altitude than at sea level (P sea level by 24 and 38%, during the low and high ATP doses...

  4. Assessment of the relationship between lung parenchymal destruction and impaired pulmonary perfusion on a lobar level in patients with emphysema

    International Nuclear Information System (INIS)

    Ley-Zaporozhan, Julia; Ley, Sebastian; Eberhardt, Ralf; Weinheimer, Oliver; Fink, Christian; Puderbach, Michael; Eichinger, Monika; Herth, Felix; Kauczor, Hans-Ulrich

    2007-01-01

    Purpose: To assess the relationship between lung parenchymal destruction and impaired pulmonary perfusion on a lobar level using CT and MRI in patients with emphysema. Material and methods: Forty-five patients with severe emphysema (GOLD III and IV) underwent inspiratory 3D-HRCT and contrast-enhanced MR-perfusion (1.5T; 3.5 mm x 1.9 mm x 4 mm). 3D-HRCT data was analyzed using a software for detection and visualization of emphysema. Emphysema was categorized in four clusters with different volumes and presented as overlay on the CT. CT and lung perfusion were visually analyzed for three lobes on each side using a four-point-score to grade the abnormalities on CT (1: predominantly small emphysema-clusters to 4: >75% large emphysema-clusters) and MRI (1: normal perfusion to 4: no perfusion). Results: A total of 270 lobes were evaluated. At CT, the score was 1 for 9 lobes, 2 for 43, 3 for 77, and 4 for 141 lobes. At MRI, the score was 1 for 13 lobes, 2 for 45, 3 for 92, and 4 for 120 lobes. Matching of lung parenchymal destruction and reduced perfusion was found in 213 lobes (weighted kappa = 0.8). The score was higher on CT in 44, and higher on MRI in 13 lobes. Conclusion: 3D-HRCT and 3D MR-perfusion show a high lobar agreement between parenchymal destruction and reduction of perfusion in patients with severe emphysema

  5. Preventing Ischial Pressure Ulcers: I. Review of Neuromuscular Electrical Stimulation

    Directory of Open Access Journals (Sweden)

    Hilton M. Kaplan

    2011-01-01

    Full Text Available Objective: Pressure ulcers (PUs are common and debilitating wounds that arise when immobilized patients cannot shift their weight. Treatment is expensive and recurrence rates are high. Pathophysiological mechanisms include reduced bulk and perfusion of chronically atrophic muscles as well as prolonged occlusion of blood flow to soft tissues from lack of voluntary postural shifting of body weight. This has suggested that PUs might be prevented by reanimating the paralyzed muscles using neuromuscular electrical stimulation (NMES. A review of the published literature over the past 2 decades is detailed.

  6. Reliable experimental setup to test the pressure modulation of Baerveldt Implant tubes for reducing post-operative hypotony

    Science.gov (United States)

    Ramani, Ajay

    Glaucoma encompasses a group of conditions that result in damage to the optic nerve and can cause loss of vision and blindness. The nerve is damaged due to an increase in the eye's internal (intraocular) pressure (IOP) above the nominal range of 15 -- 20 mm Hg. There are many treatments available for this group of diseases depending on the complexity and stage of nerve