Molecular fractionation in melt-crystallized polyethylene: 3. Microscopy of solvent-treated samples

Microscopy of melt-crystallized polyethylenes treated with hot p-xylene has revealed information concerning the morphology of the systems, in particular the distribution of the segregated low molecular weight material in the structure. It seems that this material, in accordance with earlier reports, is concentrated in the spherulite boundaries and between main lamellae within the spherulites. The effect of thermal treatment and the structure of the material on this morphological aspect is reported.     

Essential thrombocythemia at diagnosis: causes of diagnostic evaluation and presence of positive diagnostic findings

Antipsychotic drugs are effective in psychoses, whatever the aetiology of the disorder. The positive symptoms tend to respond more readily. The need for developing new drugs arises from the refractoriness of the negative symptoms, the 10-25% of the patients that are treatment-resistant and the problems of short-, and long-term extrapyramidal side-effects. Thus far, five drugs differing from the classical antipsychotics have been licensed for use: clozapine, olanzepine, risperidone, sertindole and sulpiride, and in at least some European countries quetiapine is now in the final phase of clinical research. This review starts with a brief introduction to symptomatology, is limited to the registered drugs and addresses differences with the classical drugs in pharmacology, pharmacokinetics, clinical aspects and side-effects. Clozapine, risperidone and sulpiride can be considered for clinical use in refractory patients, and these three together with olanzapine and sertindole are candidates when extrapyramidal side-effects cause a clinical problem.     

A rapid method of visualizing the pancreatic islets for studies of islet capillary blood flow using non-radioactive microspheres

A technique is described for visualization of the pancreatic islets in the rat by simple dark field illumination of pieces of the frozen and thawed pancreas. By using this method, microspheres, injected for studies of the capillary blood flow, can be readily located and counted in both the islets and the exocrine parenchyma. The procedure could be useful both for rapid estimations of the total number of islets and for studies of their microcirculation.     

Distribution of reaction in a cell with gas-evolving electrodes. I. Magnesium/silver chloride seawater battery

The effects of gas evolution on the distribution of reaction at high current densities have been studied experimentally in a model Mg-AgCl battery cell. Measurements of current, potential, pH and temperature were made at four vertical locations during discharge at applied pressures between 1–6 bar(g). Temperature and pressure were found to influence local current density with consequences for overall battery lifetime.     

An anomaly in the necking behavior of polyethylene,Part 2

Dumb-bell shaped specimens of three polyethylenes were subjected to constant uniaxial tensile loads at test temperatures from 298 to 353 K. For the high density polyethylenes, a marked transition appeared in the neck/fracture behavior. At a certain stress level, the instantaneous fracture of the neck formed at high loads was replaced by the formation of a neck that resisted fracture for a considerable time. This transition was more gradual for the medium density polyethylene. Furthermore, at all test temperatures the transition shifts towards higher nominal stresses with increasing molecular weight. Mainly on the basis of measurements of the local strain rate in the neck forming region, a hypothesis is proposed which explains the appearance of the marked transition. The draw ratios and the densities of the fractured neck fibers were also measured and are in accordance with current molecular deformation theories.     

Characterization of mixed syngeneic-allogeneic and syngeneic-xenogeneic islet-graft rejections in mice. Evidence of functional impairment of the remaining syngeneic islets in xenograft rejections

Allogeneic mouse islets or xenogeneic rat islets, or fetal porcine islets were implanted under the renal capsule of C57BL/6 mice either alone or carefully mixed with syngeneic islets. With this experimental model the syngeneic islets, although not rejected themselves, are exposed to cytokines and inflammatory mediators released during either allograft or xenograft rejection. No differences in insulin content could be observed between mixed islet grafts and pure syngeneic islet grafts 6 wk after transplantation. Neither was there any morphological evidence of a non-specific destruction of syngeneic islets. These findings suggest that the mechanisms of both allograft and xenograft rejections are highly specific. The hormone release from the mixed syngeneic-allogeneic grafts was similar to that from pure syngeneic islet grafts. In contrast, a pronounced impairment of both the first and second phases of insulin release was observed 2 wk after implantation in mixed syngeneic-xenogeneic islet grafts. When perfusing the mixed islet graft after completed rejection of the concordant xenogeneic rat islets (6 wk after implantation), the insulin release from the remaining syngeneic mouse islets was identical to that of control grafts. However, syngeneic mouse islets exposed to the rejection mechanism of the discordant xenogenic pig islet-like cell clusters did not attain a complete functional recovery.     

Determination of the absolute configuration of sugar residues using gas chromatography. Method with potential for elimination of references

The effects of the benzodiazepine receptor antagonist flumazenil (Ro 15-1799), the benzodiazepine receptor partial inverse agonist Ro 15-4513 and the benzodiazepine receptor inverse agonist beta-CCM on the behaviour of control and small platform stressed mice studied. Small platform stress was induced by placing the animals on small platforms (d = 3.5 cm) surrounded by water for 24 hours. This technique involves several factors of stress such as rapid eye movement sleep-deprivation, isolation, immobilization, falling into the water and soaking. In the plus-maze test small platform stress induced changes indicating anxiolytic action-an increase of the percentage of entries made onto and the percentage of time spent on the open arms. In control mice flumazenil (2.0 and 10.0 mg/kg), Ro 15-4513 (0.5; 1.0; 2.5; 5.0 and 10.0 mg/kg), and beta-CCM (1.0 and 2.0 mg/kg) exerted dose-dependent anxiogenic effect. The small platform stress induced an enhancement of the anxiogenic effect of flumazenil, but not that of Ro 15-4513 and beta-CCM. The selective enhancement of flumazenil's action may be explained with the mode of action of flumazenil. It is proposed that small platform stress causes changes in the concentration of the endogenous benzodiazepine receptor ligand with stress protective activity and flumazenil acts by blocking the effects of this endogenous ligand.     

Experimental haemorrhage and blood component transfusion in humans: no change in plasma concentration of thrombin-antithrombin complex and plasmin-antiplasmin complex

1. To examine whether insulin resistance in vivo is manifest equally in both muscle and adipose tissues, we measured arteriovenous glucose and lactate fluxes across forearm (muscle) and abdominal subcutaneous (adipose) tissue in nine obese, glucose-intolerant subjects and 13 non-obese subjects of similar age and sex. 2. Compared with non-obese subjects, the forearm of the obese subjects was resistant to insulin stimulation of glucose uptake after a mixed meal. In contrast, adipose tissue showed little evidence of insulin stimulation of glucose uptake, and adipose tissue in subjects in both normal and obese groups behaved very similarly (assessed per 100 g of tissue). 3. For lactate flux, adipose tissue behaved very similarly (per 100 g of tissue) in obese and non-obese subjects, and was a consistent lactate exporter. 4. We conclude that insulin resistance of glucose uptake observed in the forearm of obese subjects is not evident in adipose tissue. Adipose tissue glucose uptake in obese, insulin-resistant subjects is similar to that in lean control subjects, although it occurs at elevated circulating insulin and glucose concentrations.     

Type A factors as predictors of changes in the metabolic syndrome precursors in adolescents and young adults: A 3-year follow-up study.

The predictive associations of Type A factors with changes in some essential parameters of the cluster of disorders known as metabolic syndrome (Syndrome X) were studied during a 3-year follow-up period in 1,147 randomly selected healthy adolescents and young adults. Type A behavior was measured with the Hunter Wolf A-B Rating Scale. Physiological parameters studied were serum insulin, high-density and low-density lipoprotein cholesterol, triglycerides (TG), systolic and diastolic blood pressure, body-mass index (BMI), subscapular skinfold thickness (SSF), and centrality index. Among the Type A factors in boys and men, high baseline Aggression predicted an increase in the individual parameters of metabolic syndrome (i.e., insulin, TG, SSF, and BMI) as well as a global aggravation of the cluster of metabolic parameters. In girls and women, increases in Eagerness-Energy and Responsibility across the 3 years of follow-up predicted an increase in serum insulin and a decrease in SSF, respectively (PsycINFO Database Record (c) 2010 APA, all rights reserved)