Influence of venous emptying on reactive hyperemic blood flow

Recent work by Tschakovsky & Hughson (Am J Physiol Heart Circ Physiol 279: H1007, 2000) indicates that venous emptying serves as a stimulus for vasodilation. This suggests the importance of recognizing the potential influence of venous volume on reactive hyperemic blood flow (RHBF) following occlusion. Purpose: To examine the influence of venous emptying on RHBF. Methods: Non-dominant forearm in-flow, venous capacitance and outflow were examined in 21 individuals [age=23±2.27y]. Forearm arterial inflow, venous capacitance, and outflow were obtained two times using strain gauge plethysmography. Forearm blood inflow was estimated at rest and following 5 min of upper arm occlusion. Forearm venous capacitance and outflow were obtained following 5 min of upper arm venous occlusion pressure at 7 mmHg below diastolic blood pressure. Prior to the second measure the arm was passively elevated for 2 minutes. Immediately before returning the arm to its original position the upper arm cuff was again inflated to 240mmHg. Subsequently, RHBF and venous measures were obtained. Results: Average resting in-flow was 2.84±1.22 ml/100ml/min. RHBF was significantly greater following venous emptying (Before: 18.15±3.80; After: 23.70±5.93 ml/100ml/min, p=0.0001). Venous capacitance was also greater (Before: 1.96±0.82; After: 2.94±0.82 %, p=0.0001), whereas venous outflow (Before: 37.06±10.50; After: 39.00±10.72 ml/100ml/min, p=0.17) remained unaffected after venous emptying. Summary: Venous emptying prior to upper arm occlusion results in a significant greater RHBF response and venous capacitance. A potential explanation for the observation is a decrease in the pressure gradient across the tissue bed and/or withdrawal of the venoarteriolar reflex constriction

Influence of venous emptying on the reactive hyperemic blood flow response

BACKGROUND: Previous research indicates that venous emptying serves as a stimulus for vasodilation in the human forearm. This suggests the importance of recognizing the potential influence of venous volume on reactive hyperemic blood flow (RHBF) following occlusion. The purpose of this study was to examine the influence of venous emptying on forearm vascular function. METHODS: Forearm RHBF, venous capacitance and venous outflow were examined in 35 individuals (age = 22 ± 2 years), using mercury in-Silastic strain gauge plethysmography, at rest and following five minutes of upper arm occlusion using standard procedures (Control). In addition, the same measures were obtained following five minutes of upper arm occlusion preceded by two minutes of passive arm elevation (Pre-elevation). RESULTS: Average resting arterial inflow was 2.42 ± 1.11 ml·100 ml(-1)·min(-1). RHBF and venous capacitance were significantly greater during Pre-elevation compared to Control (RHBF; Pre-elevation: 23.76 ± 5.95 ml·100 ml(-1 )·min(-1 )vs. Control: 19.33 ± 4.50; p = 0.001), (venous capacitance; Pre-elevation: 2.74 ± 0.89 % vs. Control: 2.19 ± 0.97, p = 0.001). Venous outflow did not differ between the two conditions. CONCLUSION: Venous emptying prior to upper arm occlusion results in a significant greater RHBF response and venous capacitance. Recognition of the influence of venous volume on RHBF is particularly important in studies focusing on arterial inflow, and also provides further evidence for the interplay between the venous and arterial system

Association of Venous Function and Post-Exercise Oxygen Consumption

International Journal of Exercise Science 6(1) : 63-73, 2013. Excess post-exercise oxygen consumption (EPOC) has been attributed to metabolic, hemodynamic, neuroendocrine, and pulmonary factors. Interestingly, few studies have examined the role of venous system on EPOC. The purpose of this study was to examine the relationship between measures of vascular function and EPOC. Measures of vascular function and VO2 recovery kinetics were examined in 20 individuals [age=22+2.41 yrs]. Nondominant forearm arterial inflow, venous capacitance and venous outflow were evaluated at rest and after 5 minutes of upper arm occlusion, using strain gauge plethysmography. VO2 recovery kinetics was assessed using gas exchange analysis following a six-minute constant work rate protocol at 60 percent of VO2peak (VO2@60%), on a cycle ergometer. The average VO2peak was 33.48±8.22 ml×kg-1×min-1 (Range: 18.7 to 46.1 ml×kg-1×min-1). Following the six-minute constant work rate protocol, recovery half-time (T1/2VO2) and Tau were 17.01±3.51 seconds and 54.45±11.28 seconds, respectively. Arterial resting inflow was 2.77±1.51 ml×100ml-1×min-1, reactive hyperemic blood flow was 17.72±3.65 ml×100ml-1×min-1, venous capacitance was 2.86±0.72 percent, and venous outflow was 34.19±10.03 ml×100ml-1×min-1. Bivariate correlations revealed significant inverse associations between T1/2VO2 and the reactive hyperemic response (r=-0.48, p=0.03) and T1/2VO2 and venous outflow post-occlusion (r=-0.50, p=0.02). In conclusion, these findings suggest an important role of both the arterial and venous circulation on EPOC

Vibrational and theoretical analysis of pentyl-4-benzoyl-1[2,4-dinitrophenyl]-5phenyl-1H-pyrazole-3-carboxylate

Infrared spectrum of the compound, penty1-4-benzoyl-1-[2,4-dinitrophenyl]-5-phenyl-1H-pyrazole-3carboxylate (PBDPPC) has been measured. Conformational search through relaxed scan has been carried out to find the most stable conformational isomer. After the full geometry optimization for the most stable conformer using B3LYP and BLYP hybrid functionals of Density Functional Theory (OFT), vibrational normal modes have been calculated at the same theoretical levels. Potential Energy Distribution (PED) of each normal mode has been calculated by means of VEDA4 to obtain contributions of internal coordinates to the normal modes. Natural Bond Orbital (NBO) analysis has been performed to get insights into the possible hydrogen bonding sites for all the conformational isomers. (C) 2013 Elsevier B.V. All rights reserved

THE VALUE AND PROGNOSTIC SIGNIFICANCE OF PREOPERATIVE HEMOGLOBIN AND ALBUMIN LEVELS, AND THE LYMPHOCYTE AND PLATELET COUNT (HALP) SCORES IN PREDICTING PANCREATIC FISTULA IN PATIENTS UNDERGOING PANCREATICODUODENECTOMY DUE TO PERIAMPULLARY REGION TUMORS

Introduction.- The prognostic significance of the hemoglobin, albumlymphocyte and platelet(HALF) score has beert previously derytortstrated in 'Flatly types of malignant tumors. In this study, we aimed o determine the clinical value of MALE score in predicting postoperative pancreatic fistula and its relationship with survival patterns who underwent curative surgical resection due. to 1)eriampullary region tumors

The effect of genetic polymorphisms TLR2 and TLR4 in Turkish patients with coronary artery disease

Coronary artery disease (CAD), being a multifactorial disease process, has been suggested to be associated by the interaction of both environmental and genetic risk factors. Toll-like receptors (TLRs) are related to the receptors of the innate immune system which serves as the recognition of the conserved pathogen motifs and the activation of the signals that stimulate inflammatory genes. In this study, we investigated the relationship between the polymorphisms in the TLR2-Arg753Gly, TLR4-Asp299Gly and gene and CAD. The study population consisted of 300 patients (149 men, 151 women) with angiographically documented CAD. The polymorphisms were genotyped by real time PCR. No association between TLR2-Arg677Trp or TLR4-Asp299Gly and -Thr39911e gene polymorphisms and the presence or the severity of CAD was observed. On the other hand, the TLR2-Arg753Arg genotype seemed to have a protective effect against development of CAD (OR = 0.17; 95% Cl = 0.04-0.83). Our findings suggest that TLR2-Arg753Gly polymorphism is associated with CAD susceptibility in Turkish patients. (C) 2014 Elsevier B.V. All rights reserve

A preliminary study on the manufacturing aluminum–potassium feldspar metal matrix composite materials Eine vorläufige Studie zur Herstellung von Aluminium-Kalium-Feldspat-Metallmatrix-Verbundwerkstoffen

© 2023 Wiley-VCH GmbH.This study reports the results of a preliminary study of manufacturing aluminum–potassium feldspar metal matrix composites including its castability and mechanical properties. The material was composed considering 0.25 %, 0.5 %, and 0.75 % additive ratios to examine the impact of the amount of potassium feldspar on the material and mechanical properties of the manufactured aluminum metal matrix composite material. Aluminum alloy (A356) was utilized as the matrix of the composition. The composite material was manufactured by the stir casting technique. The modulus of elasticity, yield strength, tensile strength, elongation, density, and quality index of the material parameters was taken into account to determine the materials′ practicality. The preliminary results indicated that potassium feldspar is a promising mineral to be utilized as an additive for aluminum metal matrix composites since it has a positive impact on mechanical properties. By optimizing the casting parameters, the positive aspects of the potassium feldspar may make the material more practical to be utilized in vast engineering applications