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At least 847 records · Page 47Linked to original sources
PubMed1985

The effect of acute and chronic nicardipine therapy on forearm arterial haemodynamics in essential hypertension.

By using simultaneous recording curves obtained with pulsed Doppler velocimetry and strain gauge mechanography, forearm arterial haemodynamics were studied in 26 patients with mild to moderate essential hypertension. Fifteen patients received a single oral dose of nicardipine 40 mg, and 11 patients were treated with nicardipine 30 mg three times daily for 3 months. In both groups of patients there was a similar and significant (P less than 0.001) reduction in mean, systolic, and diastolic pressures. There was a slight increase in heart rate (P less than 0.05) after the single dose, but no change after 3 months of treatment. The diameter, blood velocity, and blood flow of the brachial artery increased significantly in both treatment groups. The decrease in forearm vascular resistance was significant for both treatment groups. Brachial artery compliance increased (P less than 0.01) and characteristic impedance decreased (P less than 0.01) after both single-dose and long-term therapy with nicardipine. In patients who received nicardipine for 3 months, there were close correlations between the baseline serum calcium level and the percent change in vascular resistance (r = -0.73, P less than 0.01), blood flow (r = 0.89, P less than 0.001), and blood velocity (r = 0.91. P less than 0.001) of the forearm. No correlation was found between the baseline serum calcium and the change in arterial pressure. This study provided evidence that the blood-pressure-lowering effect of nicardipine was accompanied by a direct vasodilatory action in the small and large arteries of the forearm. An increase in peripheral blood flow with concomitant improvement of arterial compliance are the consequences of these arterial actions.

Blood Pressure↗
PubMed1994

Effect of NG-monomethyl-L-arginine on kinin-induced vasodilation in the human forearm.

1. We compared effects of NG-monomethyl-L-arginine (L-NMMA), an NO synthase inhibitor, on vasodilator responses to intra-arterial infusion of bradykinin and substance P in the human forearm. 2. Bradykinin (100 pmol min-1) increased forearm blood flow when infused into the brachial artery of eight healthy male volunteers, from 2.8 +/- 0.2 (mean +/- s.e. mean) to 9.3 +/- 1.0 ml min-1 per 100 ml forearm volume. 3. Co-infusion of L-NMMA (2 mumol min-1 and 4 mumol min-1) with bradykinin (100 pmol min-1) for 6 min produced respectively a 9 +/- 14% and 42 +/- 14% inhibition (compared with L-NMMA vehicle) in the response to bradykinin. 4. Substance P (1 pmol min-1) when infused into the brachial artery of a further eight male subjects increased forearm blood flow from 3.4 +/- 0.2 to 6.3 +/- 0.7 ml min-1 100 ml-1. 5. Co-infusion of L-NMMA (2 mumol min-1 and 4 mumol min-1) with substance P (1 pmol min-1) for 6 min produced respectively a 27 +/- 8% and 70 +/- 13% inhibition (compared with L-NMMA vehicle) in the response to substance P. 6. These results demonstrate that vasodilator responses to both bradykinin and substance P are mediated in part via the L-arginine/NO pathway. Bradykinin and substance P may be useful agonists with which to study endothelial function in this vascular bed.

Adult↗
PubMed1994

Local L-NG-monomethyl-arginine attenuates the vasodilator action of bradykinin in the human forearm.

1. Studies in animals indicate that bradykinin relaxes blood vessels directly through an action on smooth muscle and indirectly through the release of endothelium-derived mediators. Its precise mechanism of action in the human arterial circulation is not yet known. 2. In this study the effects of a specific inhibitor of nitric oxide synthase, L-NG-monomethyl-arginine (L-NMMA) and noradrenaline on the vasodilator responses to bradykinin were examined in the forearm arterial bed of healthy volunteers. Noradrenaline was used as a control for vasoconstriction by L-NMMA; glyceryl trinitrate (GTN) as a control vasodilator acting independently of the NO synthase enzyme. 3. L-NMMA (4 mumol min-1; 5 min) alone reduced resting forearm blood flow by 44% (P < 0.01; n = 6) confirming that nitric oxide plays an important role in regulating vascular tone. 4. Bradykinin (10 and 100 pmol min-1; 3 min each dose) and GTN (2 and 5 nmol min-1; 3 min each dose) increased forearm blood flow in a dose-dependent manner (percentage changes 171 +/- 17% and 398 +/- 35%, and 176 +/- 21% and 268 +/- 42%, respectively; n = 6). 5. The response to bradykinin, but not that to GTN, was attenuated by L-NMMA compared with noradrenaline (P < 0.05; n = 6), suggesting that bradykinin-induced vasodilatation in the forearm is mediated, at least in part, by stimulating release of nitric oxide.

Adult↗
PubMed1994

Angiotensin converting enzyme inhibition does not affect the response to exogenous angiotensin II in the human forearm.

Suppression of endogenous levels of angiotensin II by angiotensin converting enzyme inhibition, may result in up-regulation of vascular AT1 receptors. We have evaluated the effects of orally administered enalapril on angiotensin II induced vasoconstriction in the human forearm. Subjects received in random order, enalapril (20 mg) or matched placebo daily for 2 weeks. Forearm blood flow response to increasing doses of angiotensin II was measured using venous occlusion plethysmography at the beginning of the study and at the end of each 2 week treatment period. Treatment with enalapril significantly reduced plasma angiotensin II levels and supine blood pressure compared with placebo. The percentage reductions in forearm blood flow in the infused arm, in response to the maximum dose of angiotensin II (50,000 fmol min-1) were 48.1 +/- 3.6% at baseline, 57.5 +/- 3.6% on placebo and 54.5 +/- 4.2% on enalapril. The differences were not significantly different. This demonstrates that suppression of plasma angiotensin II for a 14 day period does not enhance the response to exogenous intra-arterial angiotensin II in the human forearm of healthy salt replete subjects.

Administration, Oral↗
PubMed1992

Sensitivity of different areas of the flexor aspect of the human forearm to corticosteroid-induced skin blanching.

The intensity of corticosteroid-induced blanching has been found to vary at different areas of the flexor aspect of the human forearm. A retrospective analysis of 38,880 observations of skin blanching in 56 volunteers was conducted to assess the sensitivity of forearm skin to betamethasone 17-valerate. The mid-forearm appears to be more sensitive to the blanching response than do the areas close to the wrist or elbow. These results indicate that each preparation under evaluation should be applied to several sites along the forearm when using the human skin blanching assay in order to obtain an accurate comparative assessment of corticosteroid release from topical delivery vehicles.

Administration, Topical↗
PubMed1995

Pretreatment of photoaged forearm skin with topical tretinoin accelerates healing of full-thickness wounds.

Pretreatment of skin with all-trans retinoic acid (tretinoin) has been shown to enhance wound healing. Previous studies have mainly used animal models to demonstrate this effect. We wanted to determine whether pretreatment could promote wound healing in severely photoaged dorsal forearm skin. Four elderly men with severely actinically damaged forearms were treated daily for 16 weeks. One arm was treated with 0.05-0.1% tretinoin cream (Retin A, Ortho), and the other with Purpose cream (Ortho) as a vehicle control. Four-millimetre punch biopsies were taken from both dorsal forearms prior to treatment. After 16 weeks, full-thickness 2-mm punch biopsies were taken from both sides. Serial photographs were taken, and healing of the wounds quantitatively assessed by image analysis. On the 11th day, the wounds were excised using a 4-mm biopsy punch. Biopsies were processed for light microscopy. After 16 weeks, the tretinoin-treated forearms showed moderate erythema and scaling. Polarized light photographs revealed multiple, red, vascularized foci and/or a diffuse network of small vessels. The histological effects were typical for tretinoin, i.e. compaction of the stratum corneum, epidermal acanthosis with correction of atypia, an increase in small vessels, and increased cellularity in the upper dermis. Purpose cream had no effect, either clinically or histologically. On the tretinoin-treated side, the wound areas were 35-37% smaller on days 1 and 4, and 47-50% smaller on days 6, 8, 11, compared with the controls. Clinically and histologically, reepithelialization occurred more rapidly. Thus tretinoin dramatically accelerated wound healing in photodamaged skin.

Administration, Cutaneous↗
PubMed1985

Direct determination of leucine metabolism and protein breakdown in humans using L-[1-13C, 15N]-leucine and the forearm model.

We have used the forearm model to study protein metabolism in six normal healthy subjects in the fed state using L-[1-13C, 15N]-leucine as the substrate tracer. Deep venous and arterialized venous blood samples from the forearm were collected at 10-min intervals 2.5 h into a primed-continuous infusion of the dilabelled tracer. Arterialized venous blood was obtained using a 'hot-box' technique and forearm blood flow was measured by mercury strain-gauge plethysmography. The concentration and isotope enrichment of leucine and its metabolites, alpha-ketoisocaproic acid and CO2, in deep venous and arterialized venous blood were measured by gas chromatography-mass spectrometry and isotope ratio-mass spectrometry. The rates of leucine deamination and reamination were 388 +/- 24 (mean +/- SEM) and 330 +/- 23 nmol (100 ml)-1 min-1 respectively, whilst protein synthesis and breakdown rates were 127 +/- 11 and 87 +/- 10 nmol (100 ml)-1 min-1 respectively across the forearm in the fed state. We have demonstrated that the use of doubly labelled leucine as tracer and application of the mathematical model developed in this study, permits the comprehensive quantification of leucine kinetics including protein breakdown.

Adult↗
PubMed1991

Spinal and forearm bone mass in relation to ageing and menopause in healthy Italian women.

Most studies concerning bone status have been performed in Nordic and Anglo-Saxon countries and few data are available on southern European populations. We performed a cross-sectional study on spine and forearm bone mass in 234 healthy Italian women and related the results to age and time since menopause. Forearm bone mass does not decline in premenopausal age, whereas, as far as the spine is concerned, a significant reduction appears 3 years before the mean age of menopause; in both cases, the occurrence of menopause accounted for an accelerated phase of bone loss. In postmenopausal women both spine and forearm bone mass show a stronger correlation with years since menopause than with age. According to a linear exponential model, the rate of spinal bone loss per year since menopause is around 4% in the first 3 years which slows down to around 2% in the 5th year; the corresponding rates of forearm bone loss are 2% and 1.3%, respectively.

Adult↗
PubMed2006

Forearm vasoconstrictor response in uncomplicated type 1 diabetes mellitus.

BACKGROUND: According to the 'haemodynamic hypothesis', increased tissue perfusion predisposes to microangiopathy in diabetic patients. We hypothesized that the typical haemodynamic changes underlying the increased tissue perfusion can be explained by a decreased sympathetic nerve activity caused by chronic hyperglycaemia. In this study we investigated sympathetic activity in patients with uncomplicated type 1 diabetes mellitus (DM). MATERIALS AND METHODS: In 15 DM patients (DM duration 6.3 +/- 3.8 year; HbA1c 7.9 +/- 1.3%) and 16 age- and sex-matched healthy volunteers (Control), sympathetic nervous system activity was measured at rest (baseline) and during sympathoneural stimulation (lower body negative pressure (LBNP)) by means of interstitial and plasma noradrenaline (NA) sampling and power spectral analysis. Muscle sympathetic nerve activity (MSNA) was measured before (baseline) and during a cold pressure test. Forearm blood flow was measured during forearm vascular alpha- and beta-adrenergic receptor blockade. RESULTS: At baseline, forearm vascular resistance (FVR), plasma NA concentrations, MSNA and heart rate variability were similar in both groups. LBNP-induced vasoconstriction was significantly attenuated in the DM group compared with the Control group (DeltaFVR: 12 +/- 4 vs. 19 +/- 3 arbitrary units, P < 0.05). The responses of plasma NA and heart rate variability did not differ. CONCLUSIONS: Baseline FVR and sympathetic nerve activity are normal in patients with uncomplicated type 1 diabetes. However, the forearm vasoconstrictor response to sympathetic stimulation is attenuated, which cannot be attributed to an impaired sympathetic responsiveness.

Adrenergic Antagonists↗
PubMed2006

Effects of oral beraprost sodium, a prostaglandin I2 analogue, on endothelium dependent vasodilatation in the forearm of patients with coronary artery disease.

1. Previous clinical studies with prostaglandin I(2) (PGI(2)) analogue beraprost sodium suggested the potential effects on protection of cardiovascular events in patients with peripheral artery disease. Although the mechanism is not well known, experimental studies have shown protective effects of endothelial cells. This study was designed to examine the effects of beraprost sodium on vascular endothelial function in the forearm of patients with coronary artery disease. 2. Beraprost sodium (120 microg/day) was orally administered to 14 coronary artery disease patients for 4 weeks and then stopped for 4 weeks. Eleven control patients did not receive beraprost sodium treatment. Reactive hyperemia was induced in the forearm, endothelium-dependent vasodilatation was assessed by plethysmography, and urinary 8-iso-prostaglandin F(2alpha) (8-iso-PGF(2alpha)) was measured at baseline, 4 weeks and 8 weeks. 3. Both groups had similar reactive hyperemic responses at baseline. In the control group, reactive hyperemic response and urinary 8-iso-PGF(2alpha) remained unchanged for 8 weeks. In the beraprost group, maximum forearm blood flow increased significantly (P = 0.01) after 4 weeks of treatment and returned to baseline at 8 weeks. Duration of hyperemia increased significantly (P = 0.003) after 4 weeks, and remained greater than baseline at 8 weeks (P = 0.02). Urinary 8-iso-PGF(2alpha) decreased significantly (P = 0.03) after 4 weeks, and tended to be lower at 8 weeks (P = 0.07). Changes in reactive hyperemia correlated weakly but significantly with changes in 8-iso-PGF(2alpha) (P < 0.001). 4. Beraprost sodium decreased oxidative stress and improved forearm endothelium-dependent vasodilatation in coronary artery disease patients. The favorable effects on vascular endothelium could potentially lead to a decrease in vascular events.

Aged↗
PubMed1996

Laser doppler-recorded reactive hyperaemia in the forearm skin during the menstrual cycle.

OBJECTIVE: By means of laser Doppler flowmetry to describe the changes in resting microvascular perfusion and post-occlusive reactive hyperaemia in skin of the forearm and finger pulp throughout the menstrual cycle. DESIGN: Prospective descriptive study. SETTING: University Hospital of Tromso, Norway. SAMPLE: Fifteen nonsmoking healthy women were studied in the follicular (days 2 to 7) and the luteal (days 19 to 24) phase of the menstrual cycle. RESULTS: Resting perfusion in forearm and finger pulp as well as post-occlusive reactive hyperaemia in finger pulp were unchanged from the follicular to the luteal phase. The peak perfusion value of the reactive hyperaemic response after 1 min of arterial occlusion was significantly reduced from the follicular to the luteal phase (P<0.01) in forearm skin. The repayment for the blood flow debt, which is the hyperaemic response in percentage of the ischaemic build-up, was also reduced (P<0.01). After 3 min of arterial occlusion, significant reductions in peak post-occlusive flow (P<0.01), recovery time, which is the total duration of the hyperaemic response (P<0.01), and the repayment (P<0.01) were observed. A significant correlation was found between the ratio serum oestradiol/progesterone and repayment after 3 min of arterial occlusion in forearm skin (r=0.71,P<0.001). CONCLUSIONS: Vascular reactivity is altered during the menstrual cycle. In the luteal phase, significant reductions in peak perfusion, repayment and recovery time were seen. The mechanisms behind these findings are unclear, but probably involve changes in both serum oestradiol and progesterone levels.

Adolescent↗
PubMed1986

Forearm composition and muscle function in trained and untrained limbs.

The influence of a period of training, which lasts for several years, on the proportions of muscle, fat and bone present in the human forearm has been investigated by comparing trained and untrained limbs of nine experienced male tennis players. Ten healthy but untrained males of similar age served as a control group. Computed tomography (CT) scans of the forearm were made at intervals along its length to identify fat, muscle and bone and to calculate the volumes occupied by each of these components. Total forearm volume was greater in the dominant limb compared with the contralateral side in both trained (by 135 +/- 59 cm3, mean +/- SD, P less than 0.001) and untrained subjects (by 41 +/- 45 cm3, P less than 0.02). Forearm muscle volume was also greater in dominant limbs of trained (by 117 +/- 52 cm3, P less than 0.001) and untrained by 35 +/- 41 cm3, P less than 0.025) subjects. Muscle accounted for 75.4 +/- 2.7% of the total volume in the dominant arm of trained subjects compared with 71.4 +/- 4.2% in the control group (P less than 0.05). There was a greater proportion of muscle (P less than 0.05) and a smaller proportion of fat (P less than 0.001) in the trained limb compared with the contralateral limb of the same subjects. No differences in proportions of fat, muscle and bone were observed in dominant and non-dominant limbs of the control subjects. Trained subjects were able to exert a greater isometric force with the dominant limb (549 +/- 76N) than with the non-dominant limb (496 +/- 48N; P less than 0.005). There was no difference in grip strength between the arms of the untrained group (dominant: 516 +/- 107N; non-dominant: 491 +/- 91N). The ratio of strength to muscle volume was, however, the same in dominant and non-dominant arms of both groups of subjects.

Adult↗
PubMed2006

Forearm blood flow and oxygen consumption in patients with bilateral repetitive strain injury measured by near-infrared spectroscopy.

Despite the social impact of repetitive strain injury (RSI), little is known about its pathophysiological mechanism. The main objective of this study was to assess the local muscle oxygenation (mVO2) and blood flow (mBF) of the forearm in individuals with RSI during isometric contractions of the forearm. We employed the non-invasive optical technique near-infrared spectroscopy to assess forearm VO2 and BF. These variables were assessed at 10%, 20%, and 40% of their individual maximal voluntary strength. Twenty-two patients with RSI symptoms in both arms (bilateral RSI) and 30 healthy age-matched subjects participated in this cross-sectional study. The results showed lower mVO2 during exercise and a reduced mBF after exercise. The results suggest that mVO2 and mVO2 are lower in the forearms of individuals with RSI compared with their controls at similar working intensities. This finding indicates that the underlying vasculature may be impaired. Although these findings contribute to the understanding of RSI, future research is necessary to further unravel the mechanisms of this area.

Adult↗
PubMed1993

Differential inhibition by NG-monomethyl-L-arginine of vasodilator effects of acetylcholine and methacholine in human forearm vasculature.

1. We compared the effects of NG-monomethyl-L-arginine (L-NMMA), an NO synthase inhibitor, on vasodilatation produced by acetylcholine and methacholine in human forearm vasculature. 2. Acetylcholine (83 nmol min-1) infused into the brachial artery of 8 healthy volunteers caused a submaximal increase in forearm blood flow, measured by venous occlusion plethysmography, from 3.3 +/- 0.5 (mean +/- s.e. mean) to 13.3 +/- 1.7 ml min-1 100 ml-1. 3. Co-infusion of L-NMMA (4 mumol min-1) with acetylcholine (83 nmol min-1) over 6 min resulted in a 58% +/- 12% fall in the response to acetylcholine whereas during co-infusion of saline over the same time period in the same subjects (n = 8) on a different day the response to acetylcholine fell by only 9% +/- 17% (P < 0.01). 4. Methacholine (1.5 and 15 nmol min-1) increased forearm blood flow from 2.5 +/- 0.4 to 5.9 +/- 0.9 and from 3.2 +/- 0.4 to 17.0 +/- 1.9 ml min-1 100 ml-1 respectively. 5. Co-infusion of L-NMMA (4 mumol min-1) had no significant effect on the response to methacholine (1.5 or 15 nmol min-1) when compared with saline control (n = 8). Co-infusion of a higher dose of L-NMMA (8 mumol min-1) with methacholine (1.5 nmol min-1) did not significantly inhibit the vasodilator response (n = 7). 6. These results suggest that, in human forearm vasculature, methacholine acts predominantly through mechanisms other than the L-arginine/nitric oxide pathway.

Acetylcholine↗
PubMed1994

Effects of dietary marine oil supplementation on reactivity of human buttock subcutaneous arteries and forearm veins in vitro.

1. The vascular reactivity of resistance arteries isolated from gluteal skin biopsies and veins isolated from forearms of subjects fed marine oils were examined. 2. Twenty seven healthy adult males were randomly allocated to one of two different treatment groups. The first group received maxEPA (eicosapentaenoic acid 0.178 g g-1; docosahexaenoic acid 0.116 g g-1) capsules 10 g per day for 28 days while the second group received an equivalent amount of mixed oil placebo capsules. Biopsies were performed on day 29 (13 for gluteal sections; 14 for forearm vein biopsies). Subcutaneous arteries and veins were mounted in myographs and standard organ baths, respectively. 3. The internal diameter of the subcutaneous arteries at a calculated transmural pressure of 100 mmHg averaged 183.7 +/- 10.3 microns in the maxEPA group and 182.6 +/- 19.8 microns in the placebo controls. Arteries from subjects on maxEPA demonstrated increased sensitivity to angiotensin II (maxEPA vs placebo: -log EC50 (M) -8.36 +/- 0.18 vs -7.91 +/- 0.14) but not to noradrenaline or 5-hydroxytryptamine. Concentration-response curves to acetylcholine, substance P and sodium nitroprusside obtained for noradrenaline precontracted vessels were unaltered with marine oil treatment as was the concentration-response curve to calcium in K(+)-depolarized vessels. 4. Vein internal diameter at a calculated transmural pressure of 20 mmHg averaged 3.06 +/- 0.23 mm in the maxEPA group and 2.96 +/- 0.89 in the placebo group. Responses to noradrenaline, 5-hydroxytryptamine, angiotensin II and endothelin-1 were obtained in the absence and presence of indomethacin (1 microM) in veins from both maxEPA and placebo-treated subjects. Neither dietary supplementation with marine oils nor indomethacin had any effect on the responses obtained to these agonists.5. The major finding of the present study was that in general, maxEPA supplementation did not affect responses to various vasoactive substances on isolated subcutaneous arteries or forearm veins. An exception was the observation of an enhanced response to angiotensin II in subcutaneous resistance arteries studied in vitro. This effect was selective for angiotensin II and was not apparent in veins isolated from the forearm.

Adolescent↗
PubMed2004

Forearm reactive hyperemia and mortality in end-stage renal disease.

BACKGROUND: Reports on the general population indicated that decreased endothelial-mediated vasodilation has a prognostic impact on cardiovascular (CV) morbidity and mortality. Flow-dependent vasodilation of conduit arteries and ischemia-induced forearm reactive hyperemia are impaired in end-stage renal disease (ESRD). Whether deterioration of vasodilator function in ESRD patients has a prognostic impact has not been documented. The aim of this study was to determine whether the impaired forearm postischemic vasodilation is an independent predictor of mortality in ESRD patients, independently from CV end-organ damages, which are usually associated with decreased vasodilatory response. METHODS: Common carotid artery intima-media thickness (CCA-IMT), aortic stiffness (pulse wave velocity-PWV), and LV mass (LVM) were determined for 78 stable ESRD patients on hemodialysis. Forearm postischemic vasodilation [flow debt repayment (FDR)] was measured by venous plethysmography. All-cause mortality served as the outcome variable over a median follow-up of 60 +/- 27 months. RESULTS: Twenty-four deaths occurred (16 of CV origin). According to Cox regression adjusted for age, CCA-IMT, LVM, and PWV, all-cause mortality was independently associated with decreased FDR (RR 0.69 for every 10% increase; 95% CI 0.56-0.85; P= 0.0006) and increased aortic PWV (RR 1.16 for 1 m/s increase; 95% CI 1.04-1.29; P= 0.0091). CONCLUSION: Our data indicate that lower postischemic forearm reactive hyperemia is associated with all-cause mortality of ESRD patients, independently of the presence of end-organ damage such as LVH or arteriosclerosis.

Adolescent↗
PubMed1987

Blood flow in skin, subcutaneous adipose tissue and skeletal muscle in the forearm of normal man during an oral glucose load.

Blood flow to the forearm, and the subcutaneous tissue and skin in the forearm were measured by strain gauge plethysmography, 133Xe-elimination and Laser Doppler flowmetry during an oral glucose load (I g glucose kg-1 lean body mass) and during control conditions. The forearm blood flow remained constant during both experiments. Glucose induced a two-fold vasodilatation in subcutaneous tissue. In skin, glucose induced a relative vasodilatation and later a relative vasoconstriction compared with control experiments. When estimated from forearm blood flow and subcutaneous and skin blood flows, muscle blood flow decreased about 20-30% during both experiments. Proximal nervous blockade did not abolish the glucose-induced vasodilatation in subcutaneous tissue. In the glucose experiment, arterial glucose concentration increased to 7.8 +/- 1.17 mmol l-1 30 min after the load was given and then decreased to 4.5 +/- 0.34 mmol l-1 at the end of the experiment. In the control experiments glucose concentration was constant. Arterial noradrenaline concentration increased significantly from 1.0 +/- 0.13 to about 1.5 +/- 0.3 nmol l-1 120 min after glucose and remained at this level during the experiment. Similarly adrenaline increased from 0.16 +/- 0.11 to about 0.4 +/- 0.16 nmol l-1 180 min after glucose. It is hypothesized that the vasodilating effect of glucose in subcutaneous tissue is secondary to metabolic events connected to glucose uptake and energy deposition in adipose tissue.

Adipose Tissue↗
PubMed1988

Muscle capillary permeability for [14C]inulin and [51Cr]EDTA in human forearm.

Capillary permeability of [14C]inulin and [51Cr]EDTA was examined in human forearm in five healthy, subjects by indicator diffusion technique. Injections of, initially [125I]albumin and [14C]inulin, and after 30 min resting, of [125I]albumin and [51Cr]EDTA, were given in a brachial artery. During light exercise of the forearm, blood was sampled in 2-s periods from a deep cubital vein primarily draining muscles. The plasma flow rate, calculated as the dose of [125I]albumin in the injectate divided by the area under the curve for the venous concentration of 125I, was, on average, 8.5 ml min-1 100 g-1 forearm. Assuming [125I]albumin is a partially permeable tracer, a correction for extraction of albumin was performed. This gave extraction fractions of 0.107 +/- 0.015 (mean +/- SEM) for [14C]inulin and 0.377 +/- 0.033 for [51Cr]EDTA, respectively. The capillary permeability surface area product per 100 g tissue (CDC) was for [14C]inulin 0.90 +/- 0.19, and for [51Cr]EDTA 3.31 +/- 0.38 ml min-1 100 g-1 forearm. The average of the ratios of the CDC values of [51Cr]EDTA to those of [14C]inulin, 4.0 +/- 0.5, is significantly higher than the corresponding ratio between the measured free diffusion coefficients in water at 37 degrees C, 3.07 +/- 0.002 (N = 36 and 17, respectively). This indicates that there is some degree of restriction for [14C]inulin (MW 5200) relative to [51Cr]EDTA (MW 340.2) and it points to an 'equivalent pore radius estimate' of about 160 A in human muscle capillaries.

Adult↗