Chronic vitamin E treatment prevents defective endothelium-dependent relaxation in diabetic rat aorta

Summary We examined the effect in rats of 2 months of streptozotocin-induced diabetes mellitus on relaxation and contraction of aortas in vitro. A further diabetic group was treated from time of diabetes induction with a 1% dietary supplement of vitamin E. Diabetes caused a 26.5% deficit (p<0.001) in maximum endothelium-dependent relaxation to acetylcholine in phenylephrine-precontracted aortas. This was 64.3% attenuated (p<0.01) by vitamin E treatment; maximum relaxation was not significantly altered compared to non-diabetic rats. Vitamin E treatment of non-diabetic rats did not significantly affect acetylcholine-induced relaxation. Diabetes or treatment did not significantly alter acetylcholine sensitivity. Endothelium-independent relaxation response to glyceryl trinitrate was not affected by diabetes or vitamin E treatment, indicating that vascular smooth muscle responses to nitric oxide remained unaltered. There was a 35.4% reduction in the maximum contractile response to phenylephrine with diabetes (p<0.05) which was unaffected by vitamin E treatment. The data suggest that the chronic deficit in nitric oxide-mediated endothelium-dependent relaxation in diabetes depends largely upon excess activity of reactive oxygen species. Treatment with vitamin E to increase free radical scavenging specifically protected vascular endothelium although it had no effect on deficits in vascular smooth muscle contractile responses.Abbreviations NO Nitric oxide - ARI aldose reductase inhibitor - ACH acetylcholine - GTN glyceryl trinitrate - GSH reduced form of glutathione - EC₅₀ effective concentration for 50% of the maximal response     

A method to determine the time since last purification of weapons grade plutonium.

A non-destructive technique to determine the time since last purification of weapons grade plutonium based on the 241Pu decay series has been developed and demonstrated to provide results that are consistent with our historical and process knowledge. This method is based on the use of the Bateman equations and the decay chain 241Pu-->237U & 241Am-->237Np-->233Pa. Secular equilibrium is assumed between the (2.1 x 10(6) year) 237Np and the (27 day) 233Pa. The proposed method is dependent upon the efficiency of the plutonium separation process but makes no assumption about the relative abundance of 241Pu in 239Pu. Even though the technique was developed for weapons grade plutonium, it is expected to apply to almost any material that contains plutonium.     

Staging-laparoscopy

Summary. The so-called extended diagnostic laparoscopy (EDL) facilitates the comprehensive exploration of the abdominal cavity, thus improving the precision of the pretherapeutic tumor staging in gastrointestinal malignancies. EDL comprises visual inspection with a specific preparation of all relevant sites, laparoscopic sonography and retrieval of samples for biopsy and cytology. Additional relevant therapeutic information was obtained through EDL in 40.5 % of gastric cancer patients. EDL could be of similar importance for diagnosing esophageal, hepatobiliary and pancreatic malignancies.      

Effects of Helicobacter pylori on histamine and carbachol stimulated acid secretion by human parietal cells.

Helicobacter pylori (H pylori) infection is associated with hypo, normal, and hypersecretory disorders of the gastric mucosa. Pathophysiological pathways by which H pylori interacts with acid secretion are still unclear. The effects of H pylori on (14C) aminopyrine uptake by human parietal cells were examined as an indirect assay for acid secretion. Isolated oxyntic glands were stimulated with submaximal concentrations of histamine or carbachol and incubated with sonicates of different H pylori strains. Omeprazole and sonicates of Campylobacter jejuni served as positive and negative controls, respectively. Two of four H pylori strains reduced hydrochloric acid sequestration within the parietal cells significantly and in a dose dependent manner in up to 80%. Interaction with acid secretion may therefore constitute a factor contributing to a distinct pathogenicity of H pylori strains.     

Physiologic responses to heavy-resistance exercise with very short rest periods

Heavy-resistance exercise utilizing very short rest periods is commonly used by body builders to prepare for competition. The purpose of this study was to compare the acute responses of this type of heavy-resistance exercise protocol in competitive body builders (BB) and power lifters (PL). Nine male BB and eight PL were matched for age, size and experience. A ten-station heavy-resistance exercise protocol was used. Each subject performed three sets of 10 repetition maximum (RM) with 10-s rest between sets and alternated 30-s and 60-s rest periods between exercises. No differences were observed in total work between the groups, but BB used a significantly (P less than 0.05) higher percentage of their 1 RM in the bench press and leg press exercises. Heart rate, ratings of perceived exertion (RPE), and lactate levels were obtained during the exercise protocol; significant (P less than 0.05) increases were observed above rest for these variables. RPE was significantly correlated with lactate levels (r = 0.84). Plasma epinephrine, norepinephrine, dopamine, cortisol, and lactate levels significantly increased from pre- to 5 min post-exercise. Mean plasma volumes were reduced -16.6 (+/- 3.64)% and -20.6 (+/- 8.32)% following the exercise protocol for BB and PL, respectively. Significant (P less than 0.05) decreases in eosinophil counts were observed following exercise. No significant differences were observed between BB and PL for any of the physiologic responses measured. PL exhibited a higher incidence (100%) of clinical symptoms of dizziness and nausea compared to BB (11.1%).(ABSTRACT TRUNCATED AT 250 WORDS)     

A longitudinal study of the effect of different social rearing conditions on cerebrospinal fluid norepinephrine and biogenic amine metabolites in rhesus monkeys

The purpose of this study was to determine whether disruption of early social attachment alters the activity of brain biogenic amine systems in rhesus monkeys (Macaca mulatta). Male rhesus monkey infants were deprived of maternal interaction, peer interaction, or both, during the first 22 months of life. Cerebrospinal fluid (CSF) was collected under rigorously controlled conditions approximately every month and assayed for levels of norepinephrine (NE), its major metabolite, and the metabolites of dopamine and serotonin. Mother-Deprived infants had lower levels of CSF NE than Mother-Reared infants. Mother-Deprived infants also failed to develop the same pattern of intercorrelations between compounds and month-to-month stability in levels of neurotransmitter and metabolites in CSF as the Mother-Reared infants. Finally, there were changes in CSF NE levels associated with social separation and social group formation. The brain NE system appears to be sensitive to changes in the social environment. Its level of activity, as reflected in levels of NE in CSF, appears to depend on both the prevailing social environment and the prior rearing environment.     

The MTT assay for chemosensitivity testing of human tumors of the central nervous system

In this study we assessed the influence of patient- and drug-specific parameters in the short-term MTT-chemosensitivity assay in 150 primary cell cultures derived from human brain tumors. In 45 patients the MTT assay was directly compared with the CFA (Colony Forming Assay). Resistance was 10-20% higher in the MTT assay than in the CFA, but there was a good agreement in both assays, that more malignant gliomas had a higher in vitro chemosensitivity against ACNU and BCNU. Overall the results demonstrate, that there is no uniform correlation between the in vitro chemosensitivity and the histopathological classification of the tumors, which corresponds well to the clinical situation. On the basis of this study we suggest prospective clinical trials with the MTT assay in human brain tumors.