Assessment of basal insulin requirement using fasting tests in insulin-treated patients with type 2 diabetes mellitus.

AIMS: Characterizing the time course of the rise of blood glucose concentrations in the fasting state during the day and night in patients with type 2 diabetes. METHODS: 40 consecutive insulin-treated patients with type 2 diabetes underwent fasting tests on two different days with either no breakfast and lunch (fasting time of 20 hours) or no dinner (fasting time of 21 hours). Glucose-lowering medication was stopped prior to the test according to the half-life of the medication prescribed. At the start of the fasting tests, blood glucose concentrations were lowered to below 7 mmol/L using an insulin infusion. RESULTS: 26 men and 14 women were included in the study. Mean (+/-SD) age was 61+/-10 years, BMI 31+/-7 kg/m (2), and HbA1c 7.5+/-1%. Diabetes duration was 14+/-8 years and duration of insulin therapy had been prescribed for a mean of 6+/-6 years. During the daytime fast, plasma glucose concentrations rose by a mean of 0.8+/-1.6 mmol/L. During the nighttime fast, plasma glucose concentrations increased particularly after midnight, by 4.3+/-2.1 mmol/L, i.e. significantly more than during the daytime fast. CONCLUSIONS: Fasting blood glucose concentrations in the majority of insulin-treated patients with type 2 diabetes increase markedly after midnight. No similar increase is observed during the day. Thus, for most patients with type 2 diabetes, an intermediate- or long-acting insulin injected at bedtime with a peak action six to eight hours after injection should be appropriate.     

The autoinhibitory feedback control of acetylcholine release in human neocortex tissue.

Slices of human neocortex prelabelled with [3H]choline were superfused and stimulated electrically (3 Hz, 2 ms, 24 mA) in order to investigate the autoreceptor-mediated modulation of acetylcholine (ACh) release. The concentration-response curve of the muscarinic agonist oxotremorine (pKd = 6.76 +/- 0.06), which was equipotent to ACh, was shifted to the right in a parallel manner by atropine (pA2 = 8.56 +/- 0.11), as evaluated by non-linear regression analysis. Calculation of the biophase concentration of ACh showed that no ACh could be assumed to be present under these conditions, whereas following inhibition of the acetylcholinesterase by physostigmine (0.1 microM) a biophase concentration of 10(-6.89 +/- 0.11) M was estimated. The depression of ACh release due to physostigmine and tacrine, another anticholinesterase, was antagonized by atropine. When the autoinhibition was operative atropine and the M2 subtype specific muscarinic antagonists, AF-DX 116 and methoctramine, significantly increased the release of ACh whereas the 'facilitatory' effects of the M1 and M3-specific drugs, pirenzepine and hexahydrosiladifenidol, were not significant. Although different disinhibitory effects of the subtype-specific antagonists were found, they did, however, not show a pattern which would allow a clear characterisation of the subtype of muscarinic receptor associated with the autoreceptor. The release of ACh from neocortex tissue of the (non-demented) neurosurgical patients decreased with their age. This finding is consistent with the hypothesis that the normal aging process resembles a delayed and attenuated disease process of senile dementia of Alzheimer's type.(ABSTRACT TRUNCATED AT 250 WORDS)     

缺血－再灌注兔心肌肌浆网自由基的测定

应用电子自旋共振波谱仪（ＥＳＲ）直接检测了缺血－再灌注兔心肌肌浆网自由基的变化，以探讨肌质网系统与氧自由基的关系。实验中将２０只兔随机分为再灌注对照组、超氧化物歧化酶（ＳＯＤ）组、ＡＴＰ－氯化镁组和人参皂甙Ｒｅ组。实验结果，ｇ值２．００４６处为半醌自由基波谱，其相对浓度各组依次为７８．９４±２．１２６，１４．４６±２．８６，２０．６５±７．６５，１４．６６±３．６７（ｘ±ＳＤ），对照组与用药组均有显著性差异（Ｐ＜０．０５），表明缺血－再灌注兔心肌肌浆网产生大量的自由基，用ＥＳＲ可以直接检测到半醌自由基，外源性高能磷酸盐制剂ＡＴＰ－氯化镁及人参皂甙Ｒｅ与超氧化物歧化酶一样，发挥清除兔心肌肌浆网自由基的作用。     

The use of amorphous silicon flat panels as detector in neutron imaging.

A first test for neutron detection with a flat panel device based on the amorphous silicon technology is described in this report. The most important parameters defining the performance for neutron imaging are described. The first findings are encouraging for further improvements.