Rapid reversal of adaptive increases in muscle GLUT-4 and glucose transport capacity after training cessation

Previous studies have shown that when exercise is stopped there is a rapid reversal of the training-induced adaptive increase in muscle glucose transport capacity. Endurance exercise training brings about an increase in GLUT-4 in skeletal muscle. The primary purpose of this study was to determine whether the rapid reversal of the increase in maximally insulin-stimulated glucose transport after cessation of training can be explained by a similarly rapid decrease in GLUT-4. A second purpose was to evaluate the possibility, suggested by previous studies, that the magnitude of the adaptive increase in muscle GLUT-4 decreases when exercise training is extended beyond a few days. We found that both GLUT-4 and maximally insulin-stimulated glucose transport were increased approximately twofold in epitrochlearis muscles of rats trained by swimming for 6 h/day for 5 days or 5 wk. GLUT-4 was 90% higher, citrate synthase activity was 23% higher, and hexokinase activity was 28% higher in triceps muscle of the 5-day trained animals compared with the controls. The increases in GLUT-4 protein and in insulin-stimulated glucose transport were completely reversed within 40 h after the last exercise bout, after both 5 days and 5 wk of training. In contrast, the increases in citrate synthase and hexokinase activities were unchanged 40 h after 5 days of exercise. These results support the conclusion that the rapid reversal of the increase in the insulin responsiveness of muscle glucose transport after cessation of training is explained by the short half-life of the GLUT-4 protein.     

Bifurcation of singly symmetric columns

The paper derives the governing equations for the fundamental and bifurcated states of members with singly symmetric cross-sections that locally buckle in the fundamental state. The members are subject to pure compression and assumed to be geometrically perfect in the overall sense. It is shown using the fundamental state equations that fixed-ended columns exhibit overall bifurcation behaviour while pin-ended columns do not. The bifurcation equation is applied to plain channel sections and the results are compared with tests of fixed-ended columns. The variation of the bifurcation loads with the length is shown to be in good agreement with the tests. The results are shown to be sensitive to the magnitudes of local and overall geometric imperfections.     

Long-term results of macular pucker surgery

Response to treatment with antibiotics was compared with serologic reactivity and clinical symptoms in a pediatric population with presumptive diagnoses of Lyme borreliosis. The population analyzed for this study consisted of a subset of a larger Lyme clinic population being monitored as part of a prospective study on pediatric Lyme borreliosis. All patients resided in an area in which Ixodes scapularis and Borrelia burgdorferi are considered endemic. Serum from patients was tested by enzyme-linked immunosorbent assay and Western blotting. Response to antibiotics was evaluated by members of a pediatric Lyme clinic. Results showed that positive serologic test results correlate with a favorable response to antibiotics, as does the presence of erythema migrans (EM), regardless of serologic status. Seronegative patients without EM had chronic fatigue and arthralgia and/or myalgia as primary symptoms and did not respond to antibiotics, even when multiple courses of treatment were given. These results indicate that serologic tests designed to have high specificity can reliably rule out Lyme borreliosis in patients with chronic symptoms, thus preventing unnecessary treatment with antibiotics.     

Renal and vascular actions of equol in the rat

BACKGROUND: The urinary isoflavonoid equol inhibits membrane Na-K-Cl cotransporters at similar concentrations to those at which furosemide inhibits them, but the significance of this action is not known. OBJECTIVE: To investigate the potential salidiuretic and vascular actions of equol in the rat. METHODS: Renal functioning was assessed in vitro in the isolated perfused kidney and in vivo in conscious rats. The vascular contractility of isolated aorta was assessed. RESULTS: In the isolated perfused kidney equol was concentrated 50- to 70-fold in the urinary fluid, it was 3-4 times less potent than furosemide at increasing diuresis, natriuresis and kaliuresis (the difference was due to its higher protein-binding affinity), and it induced a modest but significant increase in glomerular filtration rate. In vivo, orally administered equol was a modest natriuretic agent, about 8-fold less potent than orally administered furosemide (in molar terms). In isolated aortic rings precontracted by administration of phenylephrine, administration of equol relaxed the contracted aorta at 10-fold lower concentrations (concentration for half-maximal activity 58.9 +/- 16 micromol/l, n = 3) than did furosemide (concentration for half-maximal activity 633 +/- 145 micromol/l, n = 3). CONCLUSIONS: Equol is a modest natriuretic and vasorelaxant agent in the rat. Further studies are required in order to investigate the potential natriuretic and perhaps hypotensive actions of dietary equol precursors (daidzein).     

High HIV prevalence, low condom use and gender differences in sexual behaviour among patients with STD-related complaints at a Nairobi primary health care clinic

Of 22,274 patients > or = 12 years old attending a Nairobi primary health care (PHC) clinic, 1076 (4.8%) had STD-related complaints, of whom 980 underwent assessment of risk factors for human immunodeficiency virus (HIV) infection and infrequent condom use. Gonorrhoea, chancroid, syphilis seroactivity, trichomoniasis, or objective signs of STD were found in 78%, and HIV seropositivity in 15% of men and 19% of women. Most women were married, living with a spouse; while most men were single, or married, but living separated from a spouse. Among married men, last sex was with a female sex worker (FSW) or casual partner for 60% not living with a spouse and 26% living with a spouse (P<0.005). Two or more partners during the past year were reported by 82% of men and 25% of women (P <0.001), and 55% of men and 11% of women reported the last partner was high risk. HIV seropositivity among both genders was associated with numbers of partners, and among women, with being widowed or divorced. Only 3% reported use of a condom with the last partner. Among men whose last sex was with a FSW, 74% said the reason for not using a condom was not having one. Thus, infrequent condom use, low condom availability, and gender differences in behaviour necessitate modifying development policies that separate families; and better coordination between family planning, PHC, and AIDS/STD programmes, with improved supply, social marketing and community-based distribution of condoms in high-risk settings for STD/HIV prevention.     

Abnormal colonic fermentation in irritable bowel syndrome

BACKGROUND: The cause of irritable bowel syndrome (IBS) is unknown. It may follow gastroenteritis and be associated with an abnormal gut flora and with food intolerance. Our study was designed to assess whether these factors were associated with colonic malfermentation. METHODS: We carried out a crossover controlled trial of a standard diet and an exclusion diet matched for macronutrients in six female IBS patients and six female controls. During the final 72 h on each diet, faecal excretion of fat, nitrogen, starch, and non-starch polysaccharide NSP was measured, and total excretion of hydrogen and methane collected over 24 h in a purpose-built 1.4 m3 whole-body calorimeter. Breath hydrogen and methane excretion were then measured for 3 h after 20 g oral lactulose. FINDINGS: The maximum rate of gas excretion was significantly greater in patients than in controls (2.4 mL/min IQR 1.7-2.6 vs 0.6, 0.4-1.1). Although total gas production in patients was not greater than in controls (median 527 mL/24 h IQR 387-660 vs 412, 234-507), hydrogen production was higher (332, 318-478 vs 162, 126-217, p=0.009). In patients, the exclusion diet reduced symptoms and produced a fall in maximum gas excretion (0.5 mL/min IQR 0.3-0.7). After lactulose, breath hydrogen was greater on the standard than on the exclusion diet. INTERPRETATION: Colonic-gas production, particularly of hydrogen, is greater in patients with IBS than in controls, and both symptoms and gas production are reduced by an exclusion diet. This reduction may be associated with alterations in the activity of hydrogen-consuming bacteria. Fermentation may be an important factor in the pathogenesis of IBS.     

Possible modulatory effect of browned yam flour diet on chemically-induced toxicity in the rat

The possible modulatory effect of browned yam flour, a local dietary staple in south western Nigeria, on the toxicity of 7,12-dimethylbenzanthracene (DMBA), 3-methylcholanthrene (3-MC), carbon tetrachloride (CCl4) and bromobenzene (BrB) in rats was investigated. Feeding rats with 25% browned yam flour 2 wk before treatment with 65 mg/kg DMBA (single dose) and 5 mg/kg 3-MC and continued for 3 wk significantly decreased the reduction in final body weight or weight gain and organ weights caused by the two compounds. Similarly, the diet decreased the reduction in body weight or weight gain and the increase in relative liver weight mediated by oral treatment with 0.5 ml CCl4/kg and 2.5 mmol BrB/kg body weight. Incorporation of 25% browned yam flour into rat diet significantly reduced the DMBA-mediated decrease in haemoglobin content, packed cell volume, red blood cell count and white blood cell count by 7, 5, 20 and 10%, respectively; while the diet reduced the 3-MC-mediated decrease in these parameters by 15, 28, 9 and 17%, respectively. The same diet elicited 23, 45, 13 and 33% decreases in CCl4 mediated reduction in these parameters and 23, 18, 16 and 29% in the case of BrB. Browned yam flour diet caused 10, 14 (P < 0.001) and 4% (P < 0.05) reductions in the DMBA-mediated increase in serum aspartate aminotransferase, alanine aminotransferase and serum alkaline phosphatase, respectively; and 32, 31 (P < 0.05) and 13% (P < 0.001) in the case of the 3-MC-mediated increase. Also, the diet reduced CCl4-mediated increase in the activities of these by 40, 34 and 31%, respectively and by 23, 30 and 29% following BrB treatment. These results suggest that browned yam flour diet could possibly be a modulator of chemically induced toxicity.     

Effects of age on the biomechanics and physiology of gait

There are significant changes in gait across the life span, but particularly after the age of 70 years. This article reviews the physiology of gait and the motor control challenges during gait. The kinematics (motion) and the kinetics (moment and power) of normal gait of a database of healthy young and older adults are compared. Older subjects generate significantly lower peak ankle plantar flexor power during gait. The clinical significance of the reduction in ankle plantar flexion power is discussed.     

Microangiopathy of the brain, retina, and cochlea (Susac syndrome). A report of five cases and a review of the literature

OBJECTIVE: This study reports five new cases of microangiopathy of the brain, retina, and cochlea (Susac syndrome) and reviews the world's literature. DESIGN: Five cases were systematically studied by the authors. The cases in the literature were identified through Medline searches for Susac syndrome; microangiopathy of the brain, retina, or ear; and cross-referencing the indexes of each retrieved article. PARTICIPANTS: The number of new patients studied in this report was five. An additional 41 patients were culled from the literature. INTERVENTION: Patients were treated with corticosteroids, antineoplastic agents, and other methods in a noncontrolled, nonrandomized fashion. MAIN OUTCOME MEASURES: With respect to therapeutic intervention, the main clinical outcome measures were return of vision, improvement of neurologic and psychiatric manifestations, and recovery of auditory function. Alterations of abnormalities observed by cranial magnetic resonance imaging also were monitored. RESULTS: Of 46 identified patients, 39 were women. The mean age of the patients was 30 years. Forty-one patients (89%) had arterial occlusions, which were bilateral in 60%. Thirty-one patients (67%) reported hearing loss. Twenty patients (44%) had a global encephalopathy, but other neurologic manifestations were common. The mean duration of the illness was 46.7 months. CONCLUSION: This rare syndrome is more common than previously thought, has a strong female preponderance, and often can be identified at an early stage with a careful history and physical examination. Magnetic resonance imaging of the brain often shows lesions suggestive of multiple sclerosis. Fluorescein angiography may show arteriolar wall hyperfluorescence. Early treatment with corticosteroids often is, although not invariably, associated with a good prognosis. The disease appears to be self-limited in most patients.