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PubMed2005

Bone and body composition of children and adolescents with repeated forearm fractures.

UNLABELLED: DXA measurements in 90 children and adolescents with repeated forearm fractures showed reduced ultradistal radius BMC and BMD values and elevated adiposity, suggesting site-specific bone weakness and high body weight increase fracture risk. Symptoms to cow milk, low calcium intakes, early age of first fracture, and overweight were over-represented in the sample. INTRODUCTION: Although many apparently healthy children fracture their forearms repeatedly during growth, no previous studies of their bone health and body composition have been undertaken. Nor has the prevalence of established risk factors for fracture in such a population been assessed. MATERIALS AND METHODS: Ninety children and adolescents (47 girls and 43 boys) 5-19 years of age, who had experienced at least two fractures of the forearm, were studied. Bone size and mineralization were assessed using DXA at the ultradistal radius, one-third radius, neck of femur, hip trochanter, lumbar spine, and total body. Total body lean mass and fat mass were also determined. The prevalence of six risk factors for fracture were also examined, and their influence on ultradistal BMC Z scores was assessed. RESULTS: Participants experienced 295 fractures (74.9% forearm). Children with an early age of first fracture had higher rates of fracture per l00 years of exposure than those fracturing later. Four risk factors for fracture were over-represented in observed versus expected percentages: early age of first fracture (27.7% versus 11.3%), adverse symptoms to cow milk (22.2% versus 6.7%), low dietary calcium intake (20% versus 4.5%), and overweight (33.3% versus 15.5%). However, physical activity levels were similar to the reference population. Z scores for BMC and BMD were reduced, particularly at the ultradistal radius, whereas Z scores for weight, body mass index, fat mass, and body fat percentage were increased. Mean (SD) BMC Z scores were lowest at the ultradistal radius, -0.66 (1.22), where symptoms to milk were associated with reduced values (p < 0.009) and overweight with increased values (p < 0.003). CONCLUSIONS: Our results suggest site-specific weakness and high body weight contribute to fracture risk in children and adolescents who fracture their forearms repeatedly. These findings are consonant with work showing adult Colles fractures increase as ultradistal radius BMD falls and with evidence that overweight children and adolescents are fracture prone.

Absorptiometry, Photon↗
PubMed2003

Quantitative trait loci on chromosomes 2p, 4p, and 13q influence bone mineral density of the forearm and hip in Mexican Americans.

UNLABELLED: We performed a genome scan using BMD data of the forearm and hip on 664 individuals in 29 Mexican-American families. We obtained evidence for QTL on chromosome 4p, affecting forearm BMD overall, and on chromosomes 2p and 13q, affecting hip BMD in men. INTRODUCTION: The San Antonio Family Osteoporosis Study (SAFOS) was designed to identify genes and environmental factors that influence bone mineral density (BMD) using data from large Mexican-American families. MATERIALS AND METHODS: We performed a genome-wide linkage analysis using 416 highly polymorphic microsatellite markers spaced approximately 9.5 cM apart to locate and identify quantitative trait loci (QTL) that affect BMD of the forearm and hip. Multipoint variance components linkage analyses were done using data on all 664 subjects, as well as two subgroups of 259 men and 261 premenopausal women, from 29 families for which genotypic and phenotypic data were available. RESULTS: We obtained significant evidence for a QTL affecting forearm (radius midpoint) BMD in men and women combined on chromosome 4p near D4S2639 (maximum LOD = 4.33, genomic p = 0.006) and suggestive evidence for a QTL on chromosome 12q near locus D12S2070 (maximum conditional LOD = 2.35). We found suggestive evidence for a QTL influencing trochanter BMD on chromosome 6 (maximum LOD = 2.27), but no evidence for QTL affecting the femoral neck in men and women combined. In men, we obtained evidence for QTL affecting neck and trochanter BMD on chromosomes 2p near D2S1780 (maximum LOD = 3.98, genomic p = 0.013) and 13q near D13S788 (maximum LOD = 3.46, genomic p = 0.039), respectively. We found no evidence for QTL affecting forearm or hip BMD in premenopausal women. CONCLUSION: These results provide strong evidence that a QTL on chromosome 4p affects radius BMD in Mexican-American men and women, as well as evidence that QTL on chromosomes 2p and 13q affect hip BMD in men. Our results are consistent with some reports in humans and mice. J Bone Miner Res 2003;18:2245-2252

Adolescent↗
PubMed1996

Discrimination of forearm's motions by surface EMG signals using neural network.

We tried to discriminate different forearm's motions by surface EMG signals using neural network. In order to get a higher discrimination rate, the positions of electrodes were improved. We also tried to discriminate similar motions in order to clarify the limitation of the discrimination by surface EMG signals. Two experiments were carried out. One was to discriminate five different motions: grasp, wrist flexion, wrist extension, forearm pronation, and forearm supination (Experiment 1). The other was to discriminate four similar motions which have different quantitative definitions at grasp, wrist flexion/ extension, or forearm pronation/supination (Experiment 2). Four surface electrodes were placed on the skin above the main active muscles: short radial extensor m. of wrist, supinator m., long radial extensor m. of wrist, and ulnar flexor m. of wrist, considering anatomical functions of the forearm's muscles. EMG signals were recorded during 2 sec while the subjects kept the motions. Recorded EMG signals were sampled at 200 msec intervals after full-wave rectifying and low-pass filtering. Therefore, the number of sampling data patterns of EMG signals was 10 for every motion. Three layers of neural network was used for discrimination. The number of units in the input layer is 4, and the number of units in the output layer is 5 or 4. In order to get the best discrimination rate of the motions, we changed the number of units in the hidden layer from 3 to 12. The neural network was trained by the back-propagation algorithm. In Experiment 1, the best average values of discrimination rates under three patterns of EMG signals for each subject were 96.0%, 98.0%, and 87.2% when the numbers of units in the hidden layer were 10, 11, and 3 respectively. In Experiment 2 using original EMG patterns, the best average values of discrimination rates at grasp, extension/flexion, and pronation/supination were 59.5%, 76.0%, and 25.0% respectively. By using normalized EMG patterns, these were 40.0%, 84.8%, and 55.5% respectively.

Adult↗
PubMed2002

Use of allogenic dermis for radial forearm free flap donor site coverage.

OBJECTIVE: The radial forearm free flap has become the method of choice for reconstruction of head and neck defects following oncologic ablation. Harvesting of a radial forearm free flap leaves a donor site defect. This is most commonly closed with a split-thickness skin graft. Morbidity, most commonly owing to a lack of graft take over the tendons, can be quite high. Recently, an acellular matrix (Alloderm) has been advocated to decrease complications at the radial forearm donor site, as well as obviate taking a split-thickness skin graft from the thigh. MATERIAL AND METHODS: Tertiary referral academic centre. Retrospective chart review of 15 patients. Five patients received allogenic dermis, 10 patients received split-thickness skin grafting to the radial forearm donor site. RESULTS: Patients with allogenic dermis took between 12 and 16 weeks to heal completely. Patients undergoing split-thickness skin graft were completely healed within 4 to 6 weeks. Cosmesis was judged to be marginally better in the allogenic dermis group. Allogenic dermis placement had a greater impact on hand function owing to prolonged healing, whereas patients with split-thickness skin graft required wound care at the thigh for a 2- to 3-week period owing to the harvesting of the skin graft. CONCLUSIONS: Allogenic dermis may be a viable alternative to split-thickness skin grafting and radial forearm free flap donor sites. Prolonged healing with subsequent increased health care services use needs to be addressed.

Aged↗
PubMed2004

Systemic and forearm triglyceride metabolism: fate of lipoprotein lipase-generated glycerol and free fatty acids.

Little is known about the fate of the lipolytic products produced by the action of lipoprotein lipase (LPL) on circulating triglyceride-rich lipoproteins in humans. We studied eight lean, healthy male subjects after an overnight fast. Subjects received infusions of lipid emulsions containing triolein labeled with (3)H on both the glycerol backbone and the fatty acid portion of the molecule; (14)C glycerol and (14)C oleate were coinfused to quantify the systemic and forearm release of (3)H glycerol and (3)H oleate resulting from LPL action. There was significant forearm uptake of both whole plasma triglyceride (presumed to represent primarily VLDL; extraction fraction 2.6 +/- 0.6%, P < 0.005 vs. zero) and radiolabeled triglyceride derived from the lipid emulsion (a surrogate for chylomicrons; extraction fraction 31 +/- 4%, P < 0.005 vs zero). Systemic clearance and forearm fractional extraction of glycerol was greater than that of oleate (P < 0.001 and P < 0.02, respectively). The systemic and forearm fractional release of LPL-generated glycerol were similar at 51 +/- 4 and 59 +/- 1%, respectively (NS). In contrast, the forearm fractional release of LPL-generated oleate was less than systemic fractional release (14 +/- 2 vs. 36 +/- 4%, P < 0.0001). These results indicate that there is escape, or spillover, of the lipolytic products of LPL action on triglyceride-rich lipoproteins in humans. They further suggest that LPL-mediated fatty acid uptake is an inefficient process, but may be more efficient in muscle than in adipose tissue.

Adipose Tissue↗
PubMed2002

Whole-blood glucose testing at alternate sites: glucose values and hematocrit of capillary blood drawn from fingertip and forearm.

OBJECTIVE: To measure hematocrit (Hct) and glucose concentration in capillary blood drawn from the fingertip and forearm of a group of 50 nonfasting subjects with diabetes. RESEARCH DESIGN AND METHODS: Hct was determined indirectly by measuring Hb with the HemoCue B-Hemoglobin Photometer. Glucose was assayed with the HemoCue B-Glucose Analyzer, chosen as the independent control assay, and the Sof-Tact Blood Glucose System. Testing session with each subject lasted approximately 30 min and consisted of a sequence of tests with each device (SofTact, HemoCue Glucose, and HemoCue Hemoglobin), performed on the arm and then on the fingertip. This sequence was performed three times, so all tests were done in triplicate. Additional fingersticks were performed on each subject at the start and end of the session to measure net change of glucose status during the experiment with a YSI Glucose Analyzer. The mean of the triplicate assays was used to calculate each subject's percent of glucose difference between arm and finger [(arm glucose - finger glucose)/finger glucose]. Because of the order in which replicates were performed, time-dependent changes in the glucose status of subjects had little effect on the mean values. Thus, the percent of glucose difference calculated herein reflects the intrinsic difference between forearm and fingertip. RESULTS: Hb concentration and Hct were found to be significantly higher in the arm than in the finger. When intraperson differences were calculated, the difference for Hb and Hct was found to be 1.8 +/- 1.1 g/dl (mean +/- SD) and 5.3 +/- 3.0%, respectively. In contrast to Hb, the percent of glucose difference between arm and finger was statistically insignificant. When measured with HemoCue, the percent of glucose difference was -0.1 +/- 8% for all 50 subjects, -1 +/- 6% for 20 subjects, for whom blood glucose varied <9 mg/dl during the experiment, and 2 +/- 10% for 15 subjects, for whom blood glucose varied >18 mg/dl. Thus, irrespective of how much blood glucose changed among the subjects, the glucose difference between forearm and fingertip was insignificant and less than measurement errors. A major source of error in the calculated differences was variability between replicates. No correlation was observed between an individual's Hct bias and his or her percent of glucose difference, as measured with HemoCue. The results with Sof-Tact were similar, with percent of glucose difference again being statistically insignificant. The measured difference was -4 +/- 13% for all 50 subjects, -1 +/- 15% for 20 subjects, for whom blood glucose varied <9 mg/dl during the experiment, and -1 +/- 12% for 15 subjects, for whom blood glucose varied >18 mg/dl. There was no correlation between a subject's Hct bias and his or her glucose difference, as measured with Sof-Tact. CONCLUSIONS: In this cross-sectional study of 50 nonfasting subjects whose blood glucose concentration changed to various degrees during the experiment, no significant glucose difference was observed between the capillary beds of the forearm and fingertip, regardless of whether glucose was assayed with HemoCue or the Sof-Tact Blood Glucose System. On the other hand, Hb concentration and Hct were found to be significantly higher in the capillary blood of the forearm.

Adolescent↗
PubMed2002

Comparison of static and placebo magnets on resting forearm blood flow in young, healthy men.

STUDY DESIGN: Prospective, randomized, double-blind, placebo-controlled crossover design. OBJECTIVES: To examine the effects of static magnets on resting forearm blood flow and vascular resistance. BACKGROUND: Despite little scientific evidence indicating benefits of wearing static magnets, recent reports have indicated a dramatic increase in the usage of magnets to treat a variety of medical conditions. Magnet manufacturers have proposed that one mechanism for pain reduction involves magnet-related blood flow alterations to the affected area. METHODS AND MEASURES: Twenty young, healthy men (mean age +/- SD = 25 +/- 2 years) wore commercially available static magnets and placebos for 30 minutes on 2 separate occasions. Resting forearm blood flow was assessed in triplicate at minutes 10, 20, and 30, using venous occlusion plethysmography. Forearm vascular resistance was estimated by dividing mean arterial pressure by blood flow. RESULTS: The average blood flow over the 30-minute measurement period was not significantly different between the magnet and placebo sessions (mean +/- SD for magnet session = 1.40 +/- 0.63 ml blood x 100 ml tissue(-1) x min(-1); mean +/- SD for placebo session = 1.36 +/- 0.46 ml blood x 100 ml tissue(-1) x min(-1); P = 0.66). Blood flow measurements at minutes 10, 20, and 30 were also not significantly different between the magnet and placebo sessions, and forearm vascular resistance was not different between the magnet and placebo sessions at any time (P > 0.05). CONCLUSION: Exposure to static magnets for up to 30 minutes had the same effect on resting forearm blood flow and vascular resistance as placebo magnets. These data suggest that static magnets do not result in significant alterations in resting blood flow.

Adult↗
PubMed1996

Donor site morbidity of radial forearm flaps. A clinical and ultrasonographic evaluation.

Harvesting of a forearm flap based on the radial artery has been thought to cause functional or circulatory problems in the donor hand. Eighteen patients were examined three to 24 months after a radial forearm flap had been raised. The function of both hands was studied for grip strength, mobility of the wrist and elbow joints, and sensitivity of the area served by the superficial radial nerve. The patients were interviewed and the cosmetic result was evaluated. Duplex ultrasonography and colour Doppler ultrasonography of both ulnar arteries were done, and the brachial arteries were measured as controls. Angle-corrected peak flow velocity (cm/s) in the ulnar artery of the donor forearm was significantly increased at the level of the wrist compared with the control forearm (100.9 compared with 73.1 cm/s, p = 0.017), as was the ulnar: brachial peak flow velocity ratio (1.18 compared with 0.76, p = 0.001). The grip strength of the donor hand was weaker by 11.9% (86.5 compared with 72.2 Kp), 10 (56%) had areas of sensory loss over the radial nerve distribution, and seven of the 18 patients complained of cold intolerance. Four patients considered the donor site result so bad that they would not have chosen the operation had they known what the result would look like. The radial forearm flap donor site is not without problems, and the patients must be carefully selected and properly informed preoperatively.

Adult↗
PubMed1996

How forearm position affects grip strength.

OBJECTIVE: Several studies have indicated that changing body positions results in altered grip strengths. Although one might expect that grip strength would be influenced by the position of the forearm during gripping due to the biomechanical properties of the forearm and hand muscles, no investigations of this variable have been undertaken. METHOD: This study examined the effect on grip strength of moving the forearm among supinated, neutral, and pronated positions while maintaining the standard position recommended by the American Society of Hand Therapists. The mean of three grip trials in each position was recorded for each of 106 subjects. RESULTS: Grips in forearm supination were the strongest, followed by grips in the neutral position. Grips in pronation were the weakest. CONCLUSIONS: The changes in grip strength observed with variations in forearm position further support the necessity of a standard position for testing grip strength. The knowledge of how changes in body position affect the strength of the grip can be used to design environments and tools to maximize biomechanical abilities.

Adolescent↗
PubMed1999

Symptomatic forearm muscle hernia: repair by autologous fascia lata inlay.

Eleven cases of symptomatic muscle hernias of the forearm requiring surgical intervention have been described previously. Pain on extremity exertion and an unaesthetic bulge of the forearm were the primary indications for surgery. Advocated treatment modalities range from forearm fasciotomy to anatomic repair of the fascial defect. Although fasciotomy relieves the narrow fascial constriction around the herniated muscle reliably, it often yields an unappealing forearm deformity and incomplete resolution of pain on extremity exertion. Anatomic repair provides the theoretical advantage of restoring normal muscle fascia relationships while concomitantly improving the aesthetic appearance of the extremity. The authors report a case of symptomatic forearm muscle herniation treated successfully with an autologous fascia lata inlay graft.

Adult↗
PubMed1999

Effect of mixed meal ingestion on fuel utilization in the whole body and in superficial and deep forearm tissues.

Six healthy lean male adults, given a mixed meal containing 3190 kJ (16% from protein, 44% from carbohydrate and 40% from fat) were studied for the next 370 min using arteriovenous cannulation techniques across superficial and deep forearm tissues. The meal produced no significant change in forearm blood flow or skin temperature. The major differences between superficial and deep forearm tissues were (a) creatinine release by deep tissues but not superficial tissues; (b) the release of non-esterified fatty acids (NEFA) by superficial tissues and uptake by deep tissues; and (c) the more prolonged large positive arteriovenous concentration difference for glucose across deep than superficial tissues. The similarities were (a) general pattern of individual amino acid exchanges and transient positive amino acid N balance after meal ingestion; (b) consistent uptake of glutamate and release of glutamine (the main carrier of N out of superficial and deep forearm tissues); (c) the magnitude of the arteriovenous concentration differences for glucose, NEFA and total amino acids were related to the changes in their circulating concentrations and to the oxidation of carbohydrate, fat, and protein in the whole body; and (d) increases in the arterio-deep venous and arterio-superficial venous differences for glucose did not result in increased release of lactate, alanine or pyruvate, implying no increase in the activity of glucose-lactate and glucose-alanine cycles between forearm tissues and the liver. This study suggests that in a number of ways superficial and deep tissues can be regarded, at least qualitatively, as behaving as a 'single metabolic unit'.

Adipose Tissue↗
PubMed1996

Insulin increases forearm vascular resistance in obese, insulin-resistant hypertensives.

OBJECTIVE: To determine whether acutely lowering insulin levels with somatostatin in obese, insulin-resistant hypertensive individuals reduces arterial pressure and forearm vascular resistance; and whether these changes are reversed by restoring insulin levels during continuing somatostatin infusion. SUBJECTS: Subjects were 11 obese (body mass index 36 +/- 4 kg/m2) insulin-resistant, hypertensive men (systolic/diastolic blood pressures 153 +/- 6/94 +/- 2 mmHg, aged 51 +/- 7 years, fasting insulin level 17 +/- 8 mU/l). METHODS: Arterial pressure, forearm blood flow and vascular resistance were measured during 2 h of somatostatin infusion and during 2h of somatostatin plus insulin infusion (hyperinsulinemic or euglycemic clamp). RESULTS: Somatostatin infusion decreased plasma insulin levels from 17 +/- 2 to <3 mU/l. Insulin infusion raised plasma insulin levels to 86 +/- 7 mU/l. The forearm vascular resistance decreased significantly during somatostatin infusion and increased significantly during infusion of somatostatin plus insulin. Somatostatin also caused small but significant reductions in arterial pressure whereas insulin infusion during somatostatin infusion increased arterial pressure. Control experiments in six obese hypertensives indicated that the changes in forearm vascular resistance (but not in arterial pressure) were caused neither by time nor by vehicle. Control studies in six young normotensives indicated that somatostatin does not block the vasodilator response to insulin previously demonstrated in this group. CONCLUSIONS: The present results suggest that insulin causes forearm vasoconstriction in obese, insulin-resistant hypertensive humans.

Adult↗
PubMed2002

Effect of displacement of ulna-shaft fractures on forearm rotation: a cadaveric model.

Nonoperative treatment of ulna-shaft fractures may result in healing with residual displacement. In the study reported here, we used a cadaveric model to try to determine whether displacement significantly reduces forearm supination and pronation. Transverse osteotomies were made one third, one half, and two thirds of the distance from the proximal end to the distal end of each of 7 fresh cadaveric forearms. Displacements of 50% and 100% were tested at each osteotomy site. Specimens were mounted on a material-testing machine, and forearm rotation was determined. Supination loss was less than 15 degrees for all directions of displacement at all osteotomy sites. Pronation loss was less than 10 degrees at the distal osteotomy site; at the middle osteotomy site, pronation loss was 19 degrees with 100% radial displacement (P < .05) and 20 degrees with 100% ulnar displacement (P< .05); and, at the proximal osteotomy site, pronation loss was 19 degrees with 50% radial displacement (P < .01), 41 degrees with 100% radial displacement (P < .0005), and 33 degrees with 100% ulnar displacement (P < .005). We conclude that large residual displacement in distal fractures and moderate residual displacement in midshaft fractures do not significantly compromise forearm rotation. Proximal displacement was less tolerated in this model and resulted in significantly reduced forearm rotation.

Cadaver↗
PubMed2003

Median and ulnar nerve communication in the forearm: an anatomical and electrophysiological study.

BACKGROUND: We aimed to determine the presence of median and ulnar nerve communication in the forearm by anatomical and electrophysiological examinations in the Anatolian population. MATERIAL/METHODS: 30 forearms from 15 preserved cadavers (2 females, 13 males, 42-65 years of age) were carefully dissected to observe median and ulnar nerve communication. We also performed median and ulnar nerve motor conduction studies by recording the thenar, hypothenar and first dorsal interosseous (FDI) muscles, stimulating both nerves at distal and proximal points, and the recordings were compared in 60 forearms (30 subjects, 17 female, 13 male, 34-67 years of age). RESULTS: Martin-Gruber communication was observed in 2 of 30 forearms (15 cases) by anatomical examination, in 2 of 60 forearms (30 cases) by electrophysiological examination. No Marinacci communication was found in either anatomical or electrophysiological examinations. CONCLUSIONS: In this study group, the ratio of MGC was revealed as 3.3% and 6.6%, in the electrophysiological and anatomical examination, respectively. Knowledge of this crossover is of crucial importance in the clinical evaluation of nerve injuries of the median and ulnar nerves, as well as in accurate interpretation of nerve conduction velocity of these nerves, especially in association with carpal tunnel syndrome. Anatomical and electrophysiological classifications of Martin-Gruber communication are reviewed.

Action Potentials↗
PubMed1992

Complications of forearm-plate removal.

Reconstruction of long-bone fractures with compression plates may give rise to stress shielding under the metal plate, which may be associated with late clinical problems due to insufficiency fractures around the implants. Therefore, it is common practice to remove forearm plates after fracture healing is completed. Increasing concern has been expressed recently about the complications and morbidity associated with forearm-implant removal. A retrospective review of the management of 111 forearm diaphyseal fractures at a major Canadian centre confirmed a substantial complication rate in elective forearm-plate removal. Because the true incidence of late insufficiency fracture is not well defined, elective forearm-plate removal may be contraindicated in the asymptomatic patient.

Bone Plates↗
PubMed2005

Anastomosis between the median and ulnar nerve in the forearm. An anatomic study and literature review.

Anastomosis between the median and ulnar nerve in the forearm has been shown to be of clinical significance. We aimed to determine the presence of median to ulnar nerve communications in the forearm of the Greek population by anatomical studies. At the same time we defined the types and patterns of the anastomoses found and compared them to those reported in similar studies that were retrieved after a wide review of the literature. One hundred and sixty three forearms from 100 cadavers (53 males, 47 females, 25-91 years old) were carefully dissected to observe median and ulnar nerve communication. The anastomosis was found in 10 cadavers; it was bilateral in 4 and unilateral in 6, on the right side in four and on the left side in two. It occurred in 7 of the 53 male cadavers (14%) and in 3 of the 47 females (6.5%). Overall, the anastomosis was found in 14 of the 163 forearms (8.6%). No case of ulnar to median nerve anastomosis in the forearm was found in anatomical examination.

Adult↗
PubMedDate not supplied

Effects of lipid profile on forearm hyperemic response in young subjects.

INTRODUCTION: The role of lipids in atherogenesis is now well established. However, the exact mechanisms by which different lipoproteins affect endothelial function and induce atherogenesis are still not well understood. In the present study we examined the effect of lipid profile on forearm vasodilatory response to reactive hyperemia, an index of endothelial function, in a cohort of young, low-risk adults. METHODS: One hundred sixty seven healthy subjects were included in the study. The effect of total cholesterol, high density lipoprotein (HDL), low density lipoprotein (LDL), triglycerides, apolipoprotein (apo)-A1, apo-B and apo-E on endothelial function and inflammatory process was examined. Endothelial function was evaluated by determining forearm vasodilatory response to reactive hyperemia (RH%) using gauge-strain plethysmography. RH% was defined as the % change of forearm blood flow from baseline to the maximum flow during post-ischemic hyperemia. Endothelium independent dilatation in response to nitroglycerin (NTG%) was defined as the % change of forearm blood flow from baseline to the maximum flow after sublingual nitroglycerin administration. RESULTS: RH% was correlated with HDL (r = 0.267, p = 0.001), LDL (r = 0.355, p = 0.0001), triglycerides (rho = -0.366, p = 0.0001), apo-Al (r = 0.240, p = 0.004) and apo-B (r = -0.277, p = 0.005). NTG% was not affected by serum lipid levels. In multivariate linear regression, LDL (beta = -0.217 [SE: 0.098], p = 0.028), apo-A1 (beta = 0.277 [SE: 0.124], p = 0.027) and age (beta = 0.916 [SE:0.369], p = 0.015) were independent predictors for RH% in this population (R2 for the model: 0.243, p = 0.0001). CONCLUSIONS: Elevated lipid levels decrease forearm vasodilatory response to reactive hyperemia. Apolipoproteins, and especially apo-Al, are important determinants of endothelial function in these subjects, independently of LDL, HDL and triglycerides, implying that full measurement of the lipid profile may be of great importance in risk stratification of young individuals.

Adult↗
PubMed1991

Influence of insulin on leucine kinetics in the whole body and across the forearm in post-absorptive insulin dependent diabetic (type 1) patients.

Acute effects of insulin on protein metabolism (whole body and forearm muscle) were simultaneously assessed using doubly labelled (13C15N) leucine in post-absorptive Type I diabetic patients. Whole body protein kinetics were calculated using either plasma 13C leucine or alpha-ketoisocaproic acid (alpha-KIC) enrichment to represent labelling of the precursor pool. Forearm muscle protein metabolism was measured using a previously described arterio-venous model. Acute insulin infusion (2-3 units per hour) for 2-3 hours reduced whole body protein breakdown (p < 0.01), synthesis (p < 0.05) and oxidation (p < 0.05) irrespective of the basis of calculation. Across forearm muscle, insulin reduced overall net negative protein balance (p < 0.05) by inhibiting protein breakdown, 80% and synthesis, 71%. Insulin reduced the deamination of leucine to alpha-KIC (p < 0.05) and its reamination (p < 0.05). This study demonstrates that whole body protein metabolism is broadly paralleled by events in skeletal muscle though the forearm approach is considerably more sensitive to noise than whole body protein kinetic measurements. This results from the less damped nature of the forearm model and the necessity to measure a greater number of variables required to solve the appropriate balance equations. Failure of insulin per se to promote protein synthesis in man is not model dependent and suggests that the observed differences relating to insulin mediated control of protein kinetics found in man compared with small mammals are both real and species related.

Adult↗