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At least 613 records · Page 34Linked to original sources
PubMed1997

Converting enzyme inhibitor improves forearm reactive hyperemia in essential hypertension.

Endothelial function is known to be impaired in essential hypertensive patients. In this study, we examined whether antihypertensive drugs improve forearm vasodilatory response to reactive hyperemia in 26 patients with essential hypertension (62 +/- 2 years) without diabetes mellitus, hyperlipidemia, coronary heart disease, or cerebrovascular disease. Antihypertensive drugs were never given or were discontinued for at least 4 weeks before the study. Patients were treated with monotherapy of either temocapril (2 or 4 mg, n = 15) or amlodipine (2.5 or 5 mg, n = 11) for 6 months. Forearm blood flow was measured by strain-gauge plethysmography. Vasodilator response to the release of upper arm compression at 300 mm Hg for 5 minutes and to sublingual administration of nitroglycerin (0.3 mg) were assessed. Changes of forearm blood flow response to reactive hyperemia were significantly less in hypertensive patients (99 +/- 18%) than in age-matched normotensive control subjects (150 +/- 22%, P < .01, n = 39). Blood pressure (mm Hg) was similarly decreased by the treatment with temocapril (160 +/- 4/94 +/- 2 to 139 +/- 3/83 +/- 3, P < .001) or amlodipine (165 +/- 5/94 +/- 3 to 141 +/- 4/82 +/- 3, P < .001). Response to nitroglycerin was not changed by either drug. Forearm vasodilatory response to reactive hyperemia was improved by temocapril (102 +/- 20% to 168 +/- 25%, P < .01) but not by amlodipine (97 +/- 16% to 114 +/- 14%, NS). These results indicate that the treatment with the angiotensin-converting enzyme inhibitor temocapril improved forearm vasodilatory response to reactive hyperemia, suggesting its beneficial effect on endothelial function.

Aged↗
PubMed2001

Effects of angiotensin-(1-7) on forearm circulation in normotensive subjects and patients with essential hypertension.

Previous animal studies have shown that angiotensin (Ang)-(1-7) is a biologically active component of the renin-angiotensin system, acting as a vasoactive agent, and may play a role in the blood pressure regulation. There is little information, however, on the effect of Ang-(1-7) on human circulation or the mechanism of its action. To investigate the effect of Ang-(1-7) on forearm circulation and to determine whether this effect is altered in patients with essential hypertension, we measured change in forearm blood flow using venous occlusion plethysmography in response to intra-arterial infusion of Ang-(1-7) (10(-10), 10(-9), and 10(-8) mol/min; for 5 minutes) in normotensive control subjects (n=8) and patients with essential hypertension (n=8). Infusion of Ang-(1-7) significantly increased the forearm blood flow response in a dose-dependent manner in both normotensive control subjects (28.7+/-9.7%, at 10(-8) mol/min; P<0.05) and hypertensive patients (31.8+/-15.2%, at 10(-8) mol/min; P<0.05). The vasodilatory effect of Ang-(1-7) was similar in the two groups. Intra-arterial infusion of N(G)-monomethyl-L-arginine, a nitric oxide synthesis inhibitor, did not alter the forearm blood flow response to Ang-(1-7) in either group. These findings suggest that Ang-(1-7) causes vasodilation in forearm circulation of normotensive subjects and patients with essential hypertension through a pathway that is independent of nitric oxide synthesis.

Analysis of Variance↗
PubMed1986

Augmented cardiopulmonary baroreflex control of forearm vascular resistance in young athletes.

The aim of this study was to examine the effect of exercise training on reflex control of vascular resistance in human males. Forearm vascular responses to lower body negative pressure (LBNP) at -10 and -40 mm Hg were compared between highly trained young athletes (21.5 +/- 0.5 years old, n = 14) and age-matched nonathletes (20.7 +/- 0.5 years old, n = 16). Resting heart rate was lower in athletes than in nonathletes. Resting blood pressure, central venous pressure, forearm blood flow, and forearm vascular resistance were not different between the two groups. The magnitude of reflex forearm vasoconstriction in response to LBNP at -10 mm Hg, which decreased central venous pressure but did not alter blood pressure or heart rate, was greater in athletes than in nonathletes. The slope of the regression line relating changes in central venous pressure and forearm vascular resistance was steeper in athletes than in nonathletes. Vasoconstrictive responses to intraarterially administered norepinephrine and angiotensin II did not differ between athletes and nonathletes. These results suggest that the tonic inhibitory influence of the cardiopulmonary receptors is augmented in athletes. This augmentation may contribute to some of cardiovascular and endocrine adaptations that occur with exercise training.

Adult↗
PubMed2005

Rho-kinase inhibitor improves increased vascular resistance and impaired vasodilation of the forearm in patients with heart failure.

BACKGROUND: Rho-kinase is suggested to have an important role in enhanced vasoconstriction in animal models of heart failure (HF). Patients with HF are characterized by increased vasoconstriction and reduced vasodilator responses to reactive hyperemia and exercise. The aim of the present study was to examine whether Rho-kinase is involved in the peripheral circulation abnormalities of HF in humans with the Rho-kinase inhibitor fasudil. METHODS AND RESULTS: Studies were performed in patients with HF (HF group, n=26) and an age-matched control group (n=26). Forearm blood flow was measured with a strain-gauge plethysmograph during intra-arterial infusion of graded doses of fasudil or sodium nitroprusside. Resting forearm vascular resistance (FVR) was significantly higher in the HF group than in the control group. The increase in forearm blood flow evoked by fasudil was significantly greater in the HF group than in the control group. The increased FVR was decreased by fasudil in the HF group toward the level of the control group. By contrast, FVR evoked by sodium nitroprusside was comparable between the 2 groups. Fasudil significantly augmented the impaired ischemic vasodilation during reactive hyperemia after arterial occlusion of the forearm in the HF group but not in the control group. Fasudil did not augment the increased FVR evoked by phenylephrine in the control group significantly. CONCLUSIONS: These results indicate that Rho-kinase is involved in increased FVR and impaired vasodilation of the forearm in patients with HF.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2002

Barium reduces resting blood flow and inhibits potassium-induced vasodilation in the human forearm.

BACKGROUND: Increasing extracellular K+ concentration within and just above the physiological range hyperpolarizes and relaxes vascular smooth muscle in vitro. These actions involve inwardly rectifying potassium channels (K(IR)) and Na+/K+ ATPase, which are inhibited, respectively, by Ba2+ and ouabain. The role (if any) of K(IR) in controlling human resistance vessel tone is unknown, and we investigated this in the forearm. METHODS AND RESULTS: Blood flow was measured by plethysmography in healthy men. Drugs and electrolytes were infused through the brachial artery. BaCl2 (4 micromol/min, also used in subsequent experiments) increased Ba2+ plasma concentration in the infused forearm to 50+/-0.8 micromol/L (mean+/-SEM) and reduced blood flow by 24+/-4% (n=8, P<0.001) without causing systemic effects. Ouabain (2.7 nmol/min), alone and with BaCl2, reduced flow by 10+/-2% and 28+/-3%, respectively (n=10). Incremental infusions of KCl (0.05, 0.1, and 0.2 mmol/min) increased flow from baseline by 1.0+/-0.2, 2.0+/-0.4, and 4.2+/-0.5 mL/min per deciliter forearm, respectively. Responses to KCl (0.2 mmol/min) were inhibited by BaCl2, alone and plus ouabain, by 60+/-9% and 88+/-6%, respectively (both P< or =0.01). In control experiments, norepinephrine (240 pmol/min) reduced blood flow by 24+/-2% but had no significant effect on K+-induced vasodilation. BaCl2, alone or with ouabain, did not significantly influence responses to verapamil or nitroprusside. CONCLUSIONS: Ba2+ increases forearm vascular resistance. K+-induced vasodilation is selectively inhibited by Ba2+ and almost abolished by Ba2+ plus ouabain, suggesting a role for K(IR) and Na+/K+ ATPase in controlling basal tone and in K+-induced vasorelaxation in human forearm resistance vessels.

Adult↗
PubMed1969

Amino acid balance across tissues of the forearm in postabsorptive man. Effects of insulin at two dose levels.

Amino acid balance across skeletal muscle and across subcutaneous adipose tissue plus skin of the forearm has been quantified in postabsorptive man before and after insulin infusion into the brachial artery. Skeletal muscle released significant amounts of alpha amino nitrogen after an overnight fast. Most individual amino acids were released. Alanine output was by far the greatest. The pattern of release probably reflects both the composition of muscle protein undergoing degradation and de novo synthesis of alanine by transamination. A significant correlation was observed between the extent of release of each amino acid and its ambient arterial concentration. Elevation of forearm insulin in eight subjects from postabsorptive (12 muU/ml) to high physiologic levels (157 muU/ml) in addition to stimulating muscle glucose uptake blocked muscle alpha amino nitrogen release by 74%. Consistent declines in output were seen for leucine, isoleucine, tyrosine, phenylalanine, threonine, glycine, and alpha-aminobutyric acid. Alanine output was insignificantly affected. Doubling forearm insulin levels (from 10 to 20 muU/ml) in eight subjects increased muscle glucose uptake in three and blocked alpha amino nitrogen output in two although both effects were seen concurrently in only one subject. Changes in net amino acid balance after insulin could be accounted for by increased transport of amino acids into muscle cells or retardation of their exit. It is likely that ambient arterial amino acid concentrations are established and maintained primarily by the extent of muscle amino acid release. The individual amino acids whose outputs from forearm muscle decline after forearm insulinization correspond well with those whose levels fall systematically after systemic insulinization. This suggests that declines in amino acid levels after systemic insulinization are due to inhibition of muscle release. Doubling basal insulin approaches the threshold both for blockade of muscle amino acid output and stimulation of glucose uptake, effects which appear to occur independently.

Adipose Tissue↗
PubMed1989

Vasopressin-mediated forearm vasodilation in normal humans. Evidence for a vascular vasopressin V2 receptor.

Arginine vasopressin (AVP) is a potent vasopressor and antidiuretic neurohormone. However, when administered intravenously to humans, AVP causes forearm vasodilation. This effect has been attributed to sympathetic withdrawal, secondary to AVP-induced sensitization of baroreceptors. The possibility that AVP also causes forearm vasodilation directly has not been examined. Accordingly, the direct effect of AVP was determined by studying the forearm blood flow (FBF) response to intraarterial (IA) AVP infusion (0.01-1.0 ng/kg per min). Infusion of IA AVP increased FBF (96%) in the infused arm, but not the control arm, in a dose-dependent manner. The role of specific AVP V1 receptors in mediating this FBF response was determined before and after pretreatment with a V1 antagonist (AVP-A). AVP-A alone had no effect on FBF, but coadministration of AVP and AVP-A potentiated the vasodilatory response (223%). IA infusion of the V2 agonist, 1-desamino[8-D-arginine] vasopressin, caused a dose-dependent increase in FBF. These findings suggest that AVP causes direct, dose-dependent vasodilation in the human forearm that may be mediated by V2 vasopressinergic receptors. In contrast, AVP infusion caused digital vasoconstriction that was blocked by AVP-A, whereas dDAVP did not affect digital blood flow. Thus, AVP induces regionally selective vascular effects, with concurrent forearm vasodilation and digital vasoconstriction.

Adult↗
PubMed1994

Prejunctional angiotensin II receptors. Facilitation of norepinephrine release in the human forearm.

To determine if peripheral angiotensin II (Ang II) prejunctional receptors facilitating NE release exist in humans, we used [3H]NE kinetic methodology to measure forearm NE spillover during intrabrachial arterial Ang II infusions in eight normal male subjects. We used the following protocol to optimize conditions for demonstrating these receptors: (a) lower body negative pressure (-15 mmHg) to increase sympathetic nerve activity to skeletal muscle; and (b) intraarterial nitroprusside to maintain a high constant forearm blood flow (approximately 10 ml/min.100 ml) to maximize the proportion of neuronally released NE that spills over into the circulation. During lower body negative pressure, the following were infused intraarterially for three consecutive 20-min periods: saline, Ang II (4 ng/min), and Ang II (16 ng/min). During the Ang II infusions, forearm venous NE increased significantly from 173 to 189 and 224 pg/ml (P < 0.01), and forearm NE spillover increased from 384 to 439 and 560 ng/min.100 ml (P < 0.05 for high Ang II). Forearm NE clearance was unchanged. During low and high dose Ang II, the plasma venous Ang II concentrations were 25 and 97 pM, respectively. Since normal subjects increase plasma Ang II from 4 to 20-22 pM with exercise, standing, or diuretic administration, and patients with severe congestive heart failure can have a plasma Ang II of approximately 25 pM at rest, we suggest that Ang II might facilitate NE release in severe congestive heart failure, especially under conditions of stress.

Adult↗
PubMed2000

Calf and forearm blood flow in hypercholesterolemic patients.

Patients with hypercholesterolemia without vascular disease have an impaired endothelium-dependent (nitric oxide-mediated) vasodilation in coronary and peripheral vascular beds. This study was designed to establish whether hypercholesterolemia (and its reduction) affects also the microcirculation vasomotion during postischemic hyperemia in both calf and forearm. Thirteen male patients, aged 36.2+/-8.5 years, mean +/-SD, with heterozygous familial hypercholesterolemia and 10 male control subjects, aged 32.2+/-3.6 years free from vascular lesions were studied. Plasma lipids, hematologic parameters, and limb vasoreactivity were evaluated while the patients were treated only with diet and during therapy with simvastatin. Calf and forearm blood flows were determined by venous occlusion strain gauge plethysmography at rest, during reactive hyperemia, and after sublingual isosorbide dinitrate administration. Calf resting flow rate of the hypercholesterolemic patients during and without treatment was similar to that of the controls. Calf resting vascular resistance was greater in the untreated hypercholesterolemic subjects than in the normal controls, but during treatment this difference was abolished. Peak flow during reactive hyperemia and flow debt repayment were lower in the untreated hypercholesterolemic subjects as compared to the controls, but they were normalized following hypocholesterolemic therapy. No differences were observed in forearm blood flow measurements between hypercholesterolemic subjects (without and during therapy) and control subjects. The blood flow and vascular resistance after isosorbide dinitrate were modified in a similar manner in the hypercholesterolemic (without and during therapy) and control subjects at both calf and forearm. Hypercholesterolemia does not affect vasodilation in the forearm as determined by postocclusive reactive hyperemia, while in the calf hypercholesterolemia is associated with higher resting vascular resistance, lower peak flow during reactive hyperemia, and lower flow debt repayment. These abnormalities are corrected by the hypocholesterolemic treatment.

Adult↗
PubMed1984

Abnormal reflex vasoconstriction to cold stimulation in forearm of patients with variant angina.

The responses of the blood vessels of the forearm to cold pressor test and mental stress were examined in patients with variant angina and in control subjects. In response to cold pressor test, blood pressure, heart rate and forearm vascular resistance increased with statistical significance in both groups. Percentage changes in blood pressure and heart rate were not significantly different in patients and control subjects. Percentage change in forearm vascular resistance in patients with variant angina (120 +/- 101%) was significantly greater (p less than 0.05) than that in control subjects (47 +/- 26%). In response to mental stress, percentage change in forearm vascular resistance was -20 +/- 19% in patients with variant angina and -24 +/- 18% in control subjects and there was no significant difference in the two groups. We conclude that, in some patients with variant angina, not only the coronary artery but the forearm vessels show the abnormal reflex vasoconstriction and it may be postulated that it represents the generalized abnormality of vascular smooth muscle or of their neural control which exists in some patients with variant angina.

Adult↗
PubMed2000

The effects of ipsilateral forearm movement and contralateral hand grasp on the spastic hand opened by electrical stimulation.

The purpose of this study was to investigate the effects of ipsilateral arm movement and contralateral hand grasp on the spastic hand opened by open-loop electrical stimulation. The major problem of applying proper electrical stimulation is variable spasticity, the intensity of which changes with posture and movements of other parts of the body. Electrical stimulation was applied to extensor digitorum communis and ulnar nerve to open the affected hand. Different procedures were then used to assess the effects of moving the ipsilateral forearm and contracting the contralateral normal hand. Electrical stimulation opened the spastic hand in more than 95% of trials in all subjects, whether stimulation was applied before or after the movement of the forearm. Moving the ipsilateral forearm did have an effect on opening the hand, and making adjustment of stimulation intensities was necessary in all subjects. The stimulation opened the spastic hand during the contraction of the contralateral normal hand. Electrical stimulation could open the spastic hands most of the time, in the presence of ipsilateral forearm movement and contralateral normal hand contraction. If electrical stimulation was applied before the ipsilateral forearm was moved toward the target, stimulation intensities needed to be adjusted.

Adult↗
PubMed1982

Forearm vascular resistance in the upper and lower quintiles of blood pressure in adolescent boys: The Muscatine Study.

Nineteen 16 year old white boys whose systolic blood pressures were in the upper (r = 9) and lowest (r = 10) quintile of the distribution in two school surveys in 1975 and 1977 were selected. In 1979 forearm blood flow, blood pressure and heart rate were measured at rest, and during peak reactive hyperemia. Minimal forearm vascular resistance during peak reactive hyperemia was used to assess the structural contribution to vascular resistance. At rest the high quintile group again had significantly higher blood pressures than the low quintile group but their forearm vascular resistance was not significantly different. The high quintile group showed significantly higher minimal forearm vascular resistance at peak reactive hyperemia. The latter observation suggests that there is a difference in the structural contribution to forearm vascular resistance in adolescents with blood pressure in the upper versus lower quintile of the distribution.

Adolescent↗
PubMed1999

Dual energy x-ray absorptiometry of the forearm in preterm and term infants: evaluation of the methodology.

The objective of this study was to evaluate the performance of dual energy x-ray absorptiometry (DXA) in forearm measurements of preterm and newborn term infants. The accuracy and linearity of DXA in measuring low mineral content levels (ranging from 30 to 300 mg) was assessed using bone-simulating K2HPO4 phantoms. For in vivo precision, DXA was performed twice on left forearms of four new-born term babies, 21 preterm infants at corrected age 3 mo, and 20 at corrected age 6 mo. Bone mineral content (BMC in mg) and areal bone mineral density (BMD in mg/cm2) at distal forearm and forearm shaft were measured. A special software program allowing a free adjustment of the bone detection threshold was used in the analysis of the scan data. The threshold level affected the overall ability of analysis to detect bone tissue and altered significantly the BMC and BMD values too. Given absolute success in detecting low amounts of bone mineral (BMC > 100 mg), the lowest bone detection threshold evaluated (0.040 g/cm2) became the preferable choice. The relationships between the actual and measured data were highly linear (r was 0.94 for BMC and 0.97 for BMD) but showed underestimation (corresponding slopes were 0.66 and 0.64). In vivo precision expressed as 95% limits of agreement was approximately +/-45 mg for BMC and +/-16 mg/cm2 for BMD. We conclude that DXA provides adequate reliability for in vivo determinations of BMC and areal BMD in the distal and shaft sites of forearm in term and preterm infants and thus strongly supports the clinical utility of DXA in the diagnosis and monitoring of metabolic disease of prematurity. Movements during scanning are typical of pediatric measurements and may decrease the precision considerably. Therefore, every effort must be made to prevent movement artefacts. In addition, special attention must be paid to keeping the analysis procedures consistent.

Absorptiometry, Photon↗
PubMed1986

The influence of graded hyperglycemia with and without physiological hyperinsulinemia on forearm glucose uptake and other metabolic responses in man.

We studied the influence of hyperglycemia on glucose homeostasis in man by determining the effect of graded hyperglycemia on peripheral glucose uptake and systemic metabolism in the presence of basal and increased serum insulin concentrations in 10 normal men. This was achieved by the simultaneous application of forearm and clamp techniques (euglycemic and hyperglycemic) during the combined iv infusion of somatostatin, glucagon, and insulin. While mean (+/- SE) basal serum insulin levels (14 +/- 2 microU/ml) were maintained, the elevation of fasting arterial glucose concentrations (90 +/- 1 mg/dl) to 146 +/- 1 and 202 +/- 1 mg/dl (each for 120 min) increased forearm glucose uptake (FGU) only modestly from 0.06 +/- 0.01 to 0.15 +/- 0.02 and then to 0.24 +/- 0.03 mg/100 ml forearm X min, respectively. During physiological hyperinsulinemia (47 +/- 3 microU/ml), the influence of similar graded hyperglycemia on FGU was considerably enhanced. At plasma glucose concentrations of 90 +/- 1, 139 +/- 1, and 206 +/- 1 mg/dl, FGU rose to 0.33 +/- 0.05, 0.59 +/- 0.07, and 0.83 +/- 0.12 mg/100 ml forearm X min, respectively. The glucose infusion rate required to maintain the glucose clamp with basal insulin levels was 1.08 +/- 0.20 and 2.67 +/- 0.39 mg/kg X min at glucose concentrations of 146 +/- 1 and 202 +/- 1 mg/dl, respectively. During physiological hyperinsulinemia, however, the glucose infusion rate required was 4.15 +/- 0.39, 9.45 +/- 1.05, and 12.70 +/- 0.81 mg/kg X min at glucose levels of 90 +/- 1, 139 +/- 1, and 206 +/- 1 mg/dl, respectively. Lactate concentrations rose significantly during hyperglycemia, but the rise in the presence of increased insulin concentrations (from 0.72 +/- 0.06 to 1.31 +/- 0.11 mmol/liter; P less than 0.001) considerably exceeded the increment (from 0.74 +/- 0.05 to 0.92 +/- 0.03 mmol/liter) with basal insulin levels. While both FFA and glycerol concentrations were immediately reduced by euglycemic hyperinsulinemia, the fall in FFA during hyperglycemia in the presence of basal insulin levels preceded the decrease in glycerol concentrations by 45 min. Forearm oxygen consumption did not change throughout the study.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1995

Somatostatin enhances insulin-stimulated glucose uptake in the perfused human forearm.

Somatostatin is widely used in experimental metabolic studies to control hormone actions. It has also been suggested that, in addition to its well known suppressive effects, somatostatin per se may increase insulin sensitivity. In order to examine this suggestion, we gave six healthy male volunteers (age 33 +/- 1 yr, mean +/- SEM; body mass index, 24.1 +/- 0.6 kg/m2) either a local intraarterial (brachial artery) or a systemic venous infusion of 25 micrograms/h somatostatin twice. The study consisted of a 1-h basal period and a 2-h systemic hyperinsulinemic (0.4 mU/kg.min) euglycemic clamp. Compared with the systemic control infusion, local forearm perfusion with somatostatin caused a 55% increase in insulin-stimulated forearm glucose uptake (0.74 +/- 0.18 vs. 0.47 +/- 0.19 mmol/L, P < 0.05). Intraarterial somatostatin perfusion did not alter basal forearm glucose uptake (0.14 +/- 0.07 vs. 0.17 +/- 0.12 mmol/L), the amount of glucose administered during the clamp (M-value, 3.2 +/- 0.5 vs. 3.0 +/- 0.6 mg/kg.min), or the levels of insulin, C-peptide, glucagon, or GH. Intermediary metabolite exchange across the forearm, total forearm blood flow, and oxygen saturations also remained stable. Glucose concentrations were slightly higher (0.06 +/- 0.01 mmol/L) in arterial than in arterialized blood, whereas lactate concentrations were comparatively decreased (108 +/- 51 mumol/L) in arterial blood. Our data suggest that somatostatin increases insulin-stimulated muscle utilization of glucose through local mechanisms. Although the nature of this increase remains to be established, it should be taken into consideration in metabolic studies using somatostatin.

3-Hydroxybutyric Acid↗
PubMed1997

Magnetic resonance imaging of the forearm as a diagnostic aid in patients with sporadic inclusion body myositis.

Because weakness of finger flexors and atrophy of the forearms are frequent findings in inclusion body myositis (IBM) patients, we examined the forearm muscles by MRI to determine if involvement of the distal musculature has a characteristic diagnostic pattern. We performed MRI of the forearms in 21 randomly selected patients with histologically confirmed IBM and in 9 patients with other, age-matched, neuromuscular diseases who served as controls. In addition, we analyzed axial images of 10 individual forearm muscles blindly without knowledge of the clinical status or diagnosis of the patients. T1-weighted MR images showed marbled brightness of the flexor digitorum profundus (FDP) in 20 of 21 IBM patients, of the flexor carpi ulnaris in 7, the flexor digitorum superficialis (FDS) in 6, the flexor carpi radialis in 4, the supinator in 3, and the brachioradialis in 1. The extensors were normal. The abnormalities of the FDP correlated with the severity but not the duration of the disease and in some patients preceded overt clinical signs of FDP weakness. In contrast, the FDS was spared even late in the disease. We conclude that selective involvement of the FDP may occur early in the course of IBM and can be easily demonstrated by MRI in up to 95% of patients. Because selective FDP involvement appears to be a very frequent and characteristic finding in patients with IBM, MRI of the forearm is a useful noninvasive test in supporting the diagnosis of sporadic IBM.

Adult↗
PubMed1997

L-arginine increases exercise-induced vasodilation of the forearm in patients with heart failure.

To determine whether L-arginine, a precursor of nitric oxide, can improve exercise-induced vasodilation of the forearm in patients with heart failure, we measured forearm blood flow in 9 patients with heart failure and in 7 age-matched control subjects before and after intra-arterial infusion of L-arginine. Resting forearm blood flow was significantly lower in patients with heart failure than in control subjects (2.34 +/- 0.85 (SD) vs 4.76 +/- 0.77 ml/min per 100 ml, p < 0.001). Endothelium-dependent vasodilation induced by acetylcholine was attenuated in patients with heart failure (p < 0.05). Exercise-induced vasodilation after handgrip exercise was significantly lower in patients with heart failure (p < 0.05). Intra-arterial infusion of L-arginine did not change basal forearm blood flow but significantly augmented acetylcholine-induced vasodilation in both patients with heart failure and control subjects (p < 0.05). Although L-arginine did not affect maximum forearm blood flow after handgrip exercise in control subjects (before, 26.2 +/- 13.5; after, 25.7 +/- 14.3; p = NS), it was increased in patients with heart failure (from 15.2 +/- 4.9 to 24.7 +/- 14.6, p < 0.01). The finding that L-arginine increased both acetylcholine- and exercise-induced vasodilation in patients with heart failure suggests that endothelial dysfunction might play an important role in impaired exercise-induced vasodilation in patients with heart failure.

Aged↗
PubMed2001

Treatment of unstable fractures of the forearm in children. Is plating of a single bone adequate?

Unstable fractures of the forearm in children present problems in management and in the indications for operative treatment. In children, unlike adults, the fractures nearly always unite, and up to 10 degrees of angulation is usually considered to be acceptable. If surgical intervention is required the usual practice in the UK is to plate both bones as in an adult. We studied, retrospectively, 32 unstable fractures of the forearm in children treated by compression plating. Group A (20 children) had conventional plating of both forearm bones and group B (12 children) had plating of the ulna only. The mean age was 11 years in both groups and 23 (71%) of the fractures were in the midshaft. In group B an acceptable position of the radius was regarded as less than 10 degrees of angulation in both anteroposterior (AP) and lateral planes, and with the bone ends hitched. This was achieved by closed means in all except two cases, which were therefore included in group A. Union was achieved in all patients, the mean time being 9.8 weeks in group A and 11.5 weeks in B. After a mean interval of at least 12 months, 14 children in group A and nine in group B had their fixation devices removed. We analysed the results after the initial operation in all 32 children. The 23 who had the plate removed were assessed at final review. The results were graded on the ability to undertake physical activities and an objective assessment of loss of rotation of the forearm. In group A, complications were noted in eight patients (40%) after fixation and in six (42%) in relation to removal of the radial plate. No complications occurred in group B. The final range of movement and radiological appearance were compared in the two groups. There was a greater loss of pronation than supination in both. There was, however, no limitation of function in any patient and no difference in the degree of rotational loss between the two groups. The mean radiological angulation in both was less than 10 degrees in both AP and lateral views, which was consistent with satisfactory function. The final outcome for 23 patients was excellent or good in 12 of 14 (90%) in group A, despite the complications, and in eight of nine in group B (90%). If reduction and fixation of the fracture of the ulna alone restores acceptable alignment of the radius in unstable fractures of the forearm, operation on the radius can be avoided.

Adolescent↗