Chronic administration of theophylline to rats induces a post-insulin binding defect in adipocyte glucose transport

Summary To determine whether adenosine is involved in long-term regulation of glucose transport in adipose tissue, we have investigated effects of administration of an adenosine receptor antagonist (theophylline) on adipocyte glucose transport. Rats were injected with theophylline (30 mg/kg, dissolved in 0.9% NaCl) daily for 7 days. Controls were injected with saline. The rats were then killed, and epididymal adipocytes were isolated. Insulin-stimulated glucose transport rates were decreased by about 25%–30% in the cells from theophylline-treated rats at all insulin concentrations tested. The half-maximally effective concentration of insulin was not altered (6.5±0.5 and 6.7±0.5 mU/l in control and treated cells respectively), suggesting a post-insulin binding defect. This was confirmed by the finding that ¹²⁵I-insulin binding to the cells was not altered. Adenosine receptor number and affinity (measured on detergent-solubilized adipocyte extracts using ¹²⁵I-hydroxyphenylisopropyl adenosine) was also not changed by theophylline treatment. We conclude that theophylline administration causes decreased glucose transport rates in rat adipocytes at a post-insulin binding level. Thus, chronic adenosine receptor blockade impairs adipocyte glucose transport, suggesting that adenosine is involved in long-term regulation of glucose metabolism in adipose tissue.     

High-dose contrast-enhanced computed tomography (CECT) with iopamidol in the detection of cerebral metastases

Summary Intravenously admistered iodinated contrast media have been demostrated, since early experience with computed tomography of the brain, to improve clinical value of the procedure for detecting intracranial lesions. There is no universal agreement about the amount and the method of administration of the contrast medium. Many authors maintain that the use of large doses gives better results for the diagnosis of tumors and metastases. The purpose of this paper is to evaluate the tolerance of iopamidol administered by rapid intravenous infusion in a large number of patients undergoing contrast enhanced computed tomography to detect brain metastases. The authors examined 969 consecutive adult patients suffering from lung cancer, brain metastases have been detected in 17% of cases. Adverse reactions to contrast media occurred in 3 patients. Non ionic contrast media are recommended in this diagnostic procedure.     

High-frequency ventilation (HFV) in hyaline membrane disease —a preliminary report

Eight premature babies affected by hyaline membrane disease and needing mechanical respiratory support were ventilated by means of a VDR 1 (Bird Space Technology) respirator at 10 Hz during a mean time of 51 h. Before HFV 7 infants had been on conventional mechanical ventilation (CMV) and one on nasal CPAP. The values of mean airway pressure (MAP) and oxygenation index (PaO₂/FIO₂) on CMV and HFV were (mean and range): 1. CMV: MAP 15 (4–29) mm Hg, ox. index 15.47 (5.07–23.19) kPa; 2. HFV after 1 h: MAP 15 (10–19) mm Hg, ox. index 24.13 (9.07–46.12) kPa. Improved oxygenation allowed rapid reduction of FIO₂ in the following hours. Only 3 infants were weaned directly from VDR 1, 5 were switched back to CMV mainly because of technical failures of the respirator. The change from HFV to CMV was associated with a fall of PaO₂/FIO₂ from 35.99 (15.86–74.52) to 22.39 (7.33–31.46) kPa. The mean time of artificial ventilation (CMV+HFV) was 121 h (range 46–166). Except for 1 pneumothorax no medical complications were seen during HFV, and all patients survived. Despite impressive improvements in oxygenation it is cautioned against the use of the VDR 1 because of the high incidence of technical problems.     

再论妊娠期糖尿病与胎儿生长发育

目的 研究妊娠期糖尿病与胎儿生长发育中糖代谢特点的关系。方法 选择妊娠期糖尿病25例（GDM组），正常孕妇20例（对照组），分别测孕妇空腹血糖、糖耐量、C肽、IGF－I、新生儿出生2h内空腹血糖，并依据新生儿出生体重分为大于胎龄儿组（LGA组，≥4000g），适于胎龄儿组（AGA组，2500－3999g)。结果 C肽及新生儿出生2h内空腹血糖GDM组与对照组差异有显著性；糖耐量各时点血糖值餐后2h血糖值LGA和AGA组差异有显著性。结论 血糖始终是影响胎儿生长发育的重要因素，孕妇餐后2h血糖水平与巨大儿的发生呈正相关。     

Route of lymphocyte migration through the high endothelial venule (HEV) in human palatine tonsil

Eleven palatine tonsils were collected from subjects who underwent tonsillectomy in Christian Medical College Hospital and the route of migration of lymphocytes through the high endothelial vessel was studied under EM. In the interendothelial route, migration of a lymphocyte through HEV wall began with the adhesion of a lymphocyte to the surface of endothelial cells by means of a short cytoplasmic projection in the vicinity of intercellular space. The projection extended into the cleft between adjacent endothelial cells. The lymphocyte migrated through HEV by diapedesis. After the lymphocyte had traversed the interendothelial space, it occupied the subendothelial space. In the transendothelial route, migration of a lymphocyte through HEV was initiated by adherence of the lymphocyte to the endothelial cell. The adherent lymphocyte compressed or invaginated into the cytoplasm of the endothelial cell, entered the endothelial cell, was completely enclosed within the endothelial cell cytoplasm, and emerged from the endothelial cell to occupy the subendothelial space. Evidence is presented from static transmission electron microscopic pictures for the migration of lymphocytes by both interendothelial and transendothelial routes through the high endothelial venule.     

Altered islet Beta-cell function before the onset of Type 1 (insulin-dependent) diabetes mellitus

Summary To define the glucose to insulin dose-response relationship before the onset of diabetes, we studied 22 nondiabetic co-twins of patients with Type 1 (insulin-dependent) diabetes mellitus and nine control subjects. All had intravenous glucose tests at 0.02, 0.1 and 0.5 g/kg and were followedup prospectively for at least 6 years. Seven twins developed diabetes a mean of 7 months later; the remaining 15 are now unlikely to develop diabetes. The seven pre-diabetic twins had higher fasting insulin levels than control subjects (4.2±2.0 vs 1.8±1.8 nmol/l; p<0.05); but lower glucose clearance (1.0±0.5 vs 1.9±0.7 %/min; p<0.05), first phase insulin response at 0.5 g/kg (21.1±23.2 vs 143±50 nmol/l; p<0.0001), and total insulin responses at 0.1 g/kg (p<0.05) and 0.5 g/kg (p<0.00005). Using a curve-fitting programme, the normal glucose to insulin relationship was lost in prediabetic twins who had lower coefficient of determination (R²) than control subjects (p<0.01). In contrast, 15 low-risk twins and their nine control subjects had similar fasting glucose and insulin levels, glucose clearance, R² and insulin secretory responses to different glucose loads. The positive predictive values of subnormal R² and subnormal first phase insulin response were 67 % and 58 % respectively. These observations demonstrate an altered glucose to insulin dose-response relationship and loss of maximum insulin secretory response to glucose before the onset of Type 1 diabetes.     

甲状腺功能亢进症患儿合并糖代谢紊乱10例临床分析

目的：探讨儿童甲亢患者糖代谢紊乱的特点。方法：用SUPER GLUCOCARD^TM血糖仪和放射免疫方法检测29例甲亢患儿餐前、餐后60min、120min血糖和餐前、餐后60min胰岛素、C肽、胰高糖素、皮质醇及T3、T4、TSH、TGA、TMA（其中10例糖耐量减低为甲亢1组，另19例糖耐量正常为甲亢2组），并与20例健康儿童进行比较。结果：（1）34．5％甲亢患儿出现糖代谢紊乱，病程大于1年和小于1年糖代谢紊乱发生率为50％，9％（P＜0．05）。（2）甲亢1组餐后60min胰岛素、胰岛素／血糖、胰岛素／胰高糖素显著升高（P＜0．05）。结论：甲亢儿童存在糖代谢紊乱现象，表现为葡萄糖耐量减低和胰岛素拮抗，其发生与病程有关，病程较长，发生率较高。糖代谢紊乱可能与自身免疫、胰岛β细胞功能受损及胰岛素拮抗有关。     

Evaluation of local cerebral glucose utilization and the permeability of the blood-brain barrier in the genetically epilepsy-prone rat

Summary The genetically epileptic-prone rat (GEPR) is a valuable model for the study of gene-linked abnormalities involved in epilepsy. In comparison with normal Sprague-Dawley controls, we found, in GEPRs, a marked depression in local cerebral glucose utilization, widespread throughout the brain. This depression was accompanied by a significant increase of blood-brain barrier permeability and a reduction in regional blood volume. Finally GEPRs showed lower plasma levels of total triiodothyronine than normal controls. One can speculate that alterations in cerebral metabolism and microvascular regulation and thyroid hormone imbalance may be gene-linked factors involved in seizure susceptibility.     

Acute actions of insulin-like growth factor II on glucose metabolism in adult rats

Summary The metabolic potency of recombinant human insulin-like growth factor II was studied in anaesthetized adult rats by obtaining dose-response curves for the hypoglycaemic action and for the stimulation of glucose metabolism during euglycaemic clamping. Compared to insulin, about 50 times higher doses of insulin-like growth factor II were required to result in identical in vivo responses, with half-maximally effective serum concentrations for the stimulation of glucose disposal during clamp studies of about 0.8 and 50 pmol/ml, respectively. A similar difference in potency was observed for the dose-dependent stimulatory actions on glucose metabolism in individual target tissues. Half-maximally effective serum concentrations in the range of 0.8 to 3.0 pmol/ml for insulin and of 40 to 70 pmol/ml for insulin-like growth factor II were seen to be required for 2-deoxyglucose uptake, glycogen formation in skeletal muscle and lipogenesis in epididymal fat. Maximal responses were identical with both peptides. These data suggest that in vivo acute metabolic actions of insulin-like growth factor II on carbohydrate metabolism occurred through insulin receptors.     

Glycemic Carbohydrate: An International Perspective

Attention to the different types of carbohydrates and their role in health and disease is relatively recent. FAO and WHO jointly published a report on carbohydrates in human nutrition in 1998, with a number of recommendations about increasing carbohydrate intake as a sound approach to the prevention of obesity. The glycemic index (GI) was recommended as a means of classifying foods on the basis of their potential for raising blood glucose; this concept was based on the understanding that the state of hyperglycemia that is observed following the intake of certain high-GI carbohydrate foods could constitute a risk factor for diseases of lifestyle.