Metabolic Response to a Mixed Meal in Obese and Lean Women from Two South African Populations

Objective: Lower lipid and insulin levels are found during a glucose-tolerance test in obese black than obese white South African women. Therefore, β-cell function and lipid metabolism were compared in these populations during a mixed meal. Research Methods and Procedures: Blood concentrations of glucose, free fatty acids (FFAs), insulin, lipograms, and in vivo FFA oxidation were determined at fasting and for 7 hours after oral administration of a mixed emulsion containing glucose-casein-sucrose-lipid and [1-¹³C] palmitic acid in 8 lean black women (LBW), 10 obese black women (OBW), 9 lean white women (LWW), and 10 obese white women (OWW). Subcutaneous and visceral fat mass was assessed by computerized tomography. Results: Visceral fat area was higher in OWW (152.7 ± 17.0 cm²) than OBW (80.0 ± 6.7 cm²; p < 0.01). In OBW, 30-minute insulin levels were higher (604.3 ± 117.6 pM) than OWW (311.0 ± 42.9 pM; p < 0.05). Total triglyceride was higher in OWW (706.7 ± 96.0 mM × 7 hours) than OBW (465.7 ± 48.2 mM × 7 hours; p < 0.05) and correlated with visceral fat area (β = 0.38, p = 0.05). Palmitate oxidation was higher in lean than obese women in both ethnic groups and correlated negatively with fat mass (β = −0.58, p < 0.005). Discussion: The higher 30-minute insulin response in OBW may reflect a higher insulinotropic effect of FFAs or glucose. The elevated triglyceride level of OWW may be due to their higher visceral fat mass and possibly reduced clearance by adipose tissue.     

Evaluation of Body Composition in Patients With and Without Adrenal Tumors and Without Overt Hypersecretory Syndromes

ObjectiveTo compare body composition between patients with autonomous cortisol secretion (ACS), those with nonfunctioning adrenal incidentalomas (NFAIs), and control subjects without adrenal tumors.MethodsA cross-sectional study was performed, incluidng the following 3 groups: patients with ACS (cortisol post–dexamethasone suppression test [DST] >1.8 μg/dL), NFAIs (cortisol post-DST ≤ 1.8 μg/dL), and patients without adrenal tumors (control group). Patients of the 3 groups were matched according to age (±5 years), sex, and body mass index (±5 kg/m²). Body composition was evaluated by bioelectrical impedance and abdominal computed tomography (CT) and urinary steroid profile by gas chromatography mass spectrometry.ResultsThis study enrolled 25 patients with ACS, 24 with NFAIs, and 24 control subjects. Based on CT images, a weak positive correlation between the serum cortisol level post-DST and subcutaneous fat area (r = 0.3, P =.048) was found. As assessed by bioelectrical impedance, lean mass and bone mass were positively correlated with the excretion of total androgens (r = 0.56, P <.001; and r = 0.58, P <.001, respectively); visceral mass was positively correlated with the excretion of glucocorticoid metabolites and total glucocorticoids (r = 0.28, P =.031; and r = 0.42, P =.001, respectively). Based on CT imaging evaluation, a positive correlation was observed between lean mass and androgen metabolites (r = 0.30, P =.036) and between visceral fat area, total fat area, and visceral/total fat area ratio and the excretion of glucocorticoid metabolites (r = 0.34, P =.014; r = 0.29, P =.042; and r = 0.31, P =.170, respectively).ConclusionThe urinary steroid profile observed in adrenal tumors, comprising a low excretion of androgen metabolites and high excretion of glucocorticoid metabolites, is associated with a lower lean mass and bone mass and higher level of visceral mass in patients with adrenal tumors.     

Conditions affecting the differentiation of F9 teratocarcinoma cells: Potentiation of response by cyclic amp

Summary F9 cells maintained in culture were shown to have a reduced ability to differentiate. The cells produced decreased amounts of alphafetoprotein when induced with retinoic acid. We show that consistent responses can be recovered after passage of F9 cells as a tumor. In addition, optimal differentiation of F9 cells to visceral endoderm may be achieved by the addition of very low concentrations of dibutyryl cyclic AMP (dbcAMP) to the medium. This work was supported by grants HD 18782 and P30 CA 30199 from the National Institutes of Health, Bethesda, MD.     

Schistosoma mansoni: a diamidinophenylindole probe for in vitro death of schistosomula

The following fluorochromes were studied as probes for discrimination between living and dead Schistosoma mansoni schistosomula: ethidium bromide (EB), propidium iodide (PI), diamidinophenylindole (DAPI), and carboxyfluoresceine diacetate (C-FDA). While schistosomula stained with EB, PI, or C-FDA showed leakage of fluorochrome into the medium, this was not the case with DAPI. Dead schistosomula, which were stained with DAPI, showed an intense blue fluorescence, while living schistosomula were not stained even after prolonged incubation. In addition, the low DAPI concentration (1 microgram/ml) in the medium proved not to be toxic to the schistosomula, nor did it cause any background fluorescence. These properties make DAPI an ideal probe: the viability of S. mansoni schistosomula in cytotoxicity tests can be continuously monitored in tissue culture trays, using an inverted microscope with simultaneous transmitted light and incident fluorescent light illumination.     

Non-linear multimodal integration in a distributed premotor network controls proprioceptive reflex gain in the insect leg

1. Download : Download high-res image (183KB)
2. Download : Download full-size image

     

Hypokinetic stress-induced modifications of the pain sensitivity in rats

We examined the modifying effect of hypokinetic stress on the duration of behavioral phenomena in rats under conditions of experimentally induced tonic somatic, visceral, acute thermal, and electrostimulation-evoked pain. Stress of the above type (hypokinetic) was found to modify the pain sensitivity in rats related to all tested types of pain stresses of different etiology. Changes in the pain sensitivity of the animals under conditions of experimental pain tests depended on the duration of mobility restriction and could demonstrate opposite directions. Neirofiziologiya/Neurophysiology, Vol. 39, No. 2, pp. 174–183, March–April, 2007.     

Body Compartment and Subcutaneous Adipose Tissue Distribution - Risk Factor Patterns in Obese Subjects

The purpose of this study was to investigate whether upper body obesity and/or visceral obesity are related to cardiovascular risk factors among severely obese subjects, phenomena that have previously been reported in more heterogeneous body weight distri -buttons. 2450 severely obese men and women aged 37 to 59 years, with a body mass index of 39 ± 4.5 kg/m² (mean ± SD) were examined cross-sectionally. Eight cardiovascular risk factors were studied in relation. to the following body composition indicators: four trunk and three limb circumferences, along with weight, height and sagittal trunk diameter. From the latter three measurements lean body mass (LBM, i.e., the non-adipose tissue mass) and the masses of subcutaneous and visceral adipose tissue were estimated by using sex-specific prediction equations previously calibrated by computed tomography. Two risk factor patterns could be distinguished: 1. One body compartment- risk factor pattern in which the subcutaneous adipose tissue (AT) mass and, in particular, the visceral AT mass were positively related to most risk factors while the lean body mass was negatively related to some risk factors. 2. One subcutaneous adipose tissue distribution- risk factor pattern in which the neck circumference was positively and the thigh circumference negatively related to several risk factors. It is concluded that lean body mass (LBM), visceral and subcutaneous adipose tissue masses as well as neck and thigh circumferences, used as indices of subcutaneous adipose tissue distribution, are independently related to cardiovascular risk factors in severely obese men and women.     

海马背部微量注射埃托啡对家兔内脏大神经伤害性刺激引起回缩反应的影响

慢性实验中,电刺激清醒家兔内脏大神经模拟内脏痛刺激,以前肢回缩反应(Withdrawreaction,WR)为痛反应指标,探讨了背海马内微量注射埃托啡对WR阈值的影响。结果表明:(1)单侧海马内微量注射埃托啡2μg/2μl,可显著提高兔WR阈值,作用维持20min。(2)该效应对剂量有依从关系,并能被静脉注射0.4mg/kg纳洛酮拮抗。(3)海马内微量注射埃托啡后,WR阈值提高和呼吸频率抑制呈分离现象。提示:海马内阿片受体可能参与内脏痛的镇痛作用。     

Impact of Visceral Fat on Blood Pressure and Insulin Sensitivity in Hypertensive Obese Women

Objective: The relationship among body fat distribution, blood pressure, serum leptin levels, and insulin resistance was investigated in hypertensive obese women with central distribution of fat. Research Methods and Procedures: We studied 74 hypertensive women (age, 49.8 ± 7.5 years; body mass index, 39.1 ± 5.5 kg/m²; waist-to-hip ratio, 0.96 ± 0.08). All patients were submitted to 24-hour blood pressure ambulatory monitoring (24h-ABPM). Abdominal ultrasonography was used to estimate the amount of visceral fat (VF). Fasting blood samples were obtained for serum leptin and insulin determinations. Insulin resistance was estimated by homeostasis model assessment insulin resistance index (HOMA-r index). Results: Sixty-four percent of the women were postmenopausal, and all patients showed central distribution of fat (waist-to-hip ratio > 0.85). The VF correlated with systolic 24h-ABPM values (r = 0.28, p = 0.01) and with HOMA-r index (r = 0.27; p = 0.01). VF measurement (7.5 ± 2.3 vs. 5.9 ± 2.2 cm, p < 0.001) and the systolic 24h-ABPM (133 ± 14.5 vs. 126 ± 9.8 mm Hg, p = 0.04), but not HOMA-r index, were significantly higher in the postmenopausal group (n = 48) than in the premenopausal group (n = 26). No correlations were observed between blood pressure levels and HOMA-r index, leptin, or insulin levels. In the multiple regression analysis, visceral fat, but not age, body fat mass, or HOMA-r index, correlated with the 24h-ABPM (p = 0.003). Discussion: In centrally obese hypertensive women, the accumulation of VF, more often after menopause, is associated with higher levels of blood pressure and insulin resistance. The mechanism through which VF contributes to higher blood pressure levels seems to be independent of leptin or insulin levels.