Endothelial dysfunction and metabolic control in streptozotocin-induced diabetic rats

1. The aim of this work was to study the influence of the metabolic control, estimated by the levels of glycosylated haemoglobin in total blood samples (HbA1c), in developing vascular endothelial dysfunction in streptozotocin-induced diabetic rats. Four groups of animals with different levels of insulin treatment were established, by determining HbA1c values in 5.5 to 7.4%, 7.5 to 9.4%, 9.5 to 12% and > 12%, respectively. 2. The parameters analysed were: (1) the endothelium-dependent relaxations to acetylcholine (ACh) in isolated aorta and mesenteric microvessels; (2) the vasodilator responses to exogenous nitric oxide (NO) in aorta: and (3) the existence of oxidative stress by studying the influence of the free radical scavenger superoxide dismutase (SOD) on the vasodilator responses to both ACh and NO. 3. In both isolated aortic segments and mesenteric microvessels, the endothelium-mediated concentration-dependent relaxant responses elicited by ACh were significantly decreased when the vessels were obtained from diabetic animals but only with HbA1c values higher than 7.5%. There was a high correlation between HbA1c levels and the impairment of ACh-induced relaxations, measured by pD2 values. 4. The concentration-dependent vasorelaxant responses to NO in endothelium-denuded aortic segments were significantly reduced only in vessels from diabetic animals with HbA1c values higher than 7.5%. Again, a very high correlation was found between the HbA1c values and pD2 for NO-evoked responses. 5. In the presence of SOD, the responses to ACh or NO were only increased in the segments from diabetic rats with HbA1c levels higher than 7.5%, but not in those from non-diabetic or diabetic rats with a good metabolic control (HbA1c levels <7.5%). 6. These results suggest the existence of: (1) a close relation between the degree of endothelial dysfunction and the metabolic control of diabetes, estimated by the levels of HbA1c; and (2) an increased production of superoxide anions in the vascular wall of the diabetic rats, which is also related to the metabolic control of the disease.     

Intracardiac thrombi associated with antiphospholipid antibodies

Two cases of intracardiac thrombi associated with antiphospholipid antibodies are presented, one in the right atrium and the other in the left ventricle, the latter occurring in the presence of normal left ventricular function. In each, the diagnosis was made by transthoracic echocardiography. Both patients had contraindications to thrombolytic therapy and underwent successful surgical thrombectomy. We suggest that serial transthoracic echocardiography may be warranted in the follow-up of patients with primary hypercoagulable states.     

Regulation and function of Bcl-2 during differentiation-induced cell death in HL-60 promyelocytic cells

Polymorphonuclear leukocytes are generated by differentiation of early myeloid precursors. Once fully differentiated, blood neutrophils are programmed to die rapidly and are removed by tissue macrophages. In normal myeloid cells, the death mechanism seems to be coupled to the differentiation pathway and is accomplished by a process termed apoptosis. In the present study, we have examined the role of Bcl-2 in the differentiation pathways of the promyelocytic cell line HL-60. Treatment of HL-60 with retinoic acid or phorbol ester, which induced neutrophil or macrophage-like cell differentiation, respectively, resulted in progressive loss of cellular viability and internucleosomal DNA degradation. In HL-60, differentiation and apoptosis were coupled to down-regulation of the Bcl-2 protein. Overexpression of Bcl-2 by gene transfer inhibited apoptosis triggered by terminal differentiation of HL-60. Yet, Bcl-2 did not alter the expression of surface markers or other phenotypic changes that are induced upon myeloid differentiation. In contrast to HL-60, another immature myeloid cell line, K562, did not produce Bcl-2 but expressed a related protein, Bcl-xL, that functions as a repressor of apoptotic cell death. K562 has been shown to be relatively resistant to a variety of apoptotic stimuli. Incubation of HL-60 and K562 with inhibitors of macromolecular synthesis induced apoptosis, which appeared earlier in HL-60 than in K562. Interestingly, Bcl-2 overexpression protected K562 cells from apoptosis induced by inhibitor of macromolecular synthesis but it had little or no effect on HL-60 cells. We conclude that although differentiation and apoptosis proceed simultaneously, they can be uncoupled by expression of Bcl-2. Down-regulation of Bcl-2 appears to be part of the differentiation pathway and may serve to facilitate the apoptotic response.     

A clearer view of upper motor neuron dysfunction in amyotrophic lateral sclerosis

The Arrhenius and z-value models were compared for thermal inactivation analysis of a mesophilic bacterium. The models produced a linear curve for the thermal inactivation data. Concerning the rate constant of inactivation, the D and k values predicted by the models at a constant temperature were similar. For extrapolated temperatures the z-value model predicted an insignificant decrease in the survival ratio compared to the Arrhenius model. The dynamic temperature survival curves predicted by the models were similar, and the models characterized the results. These results demonstrated that the models can be used for thermal inactivation analysis of mesophiles at various temperatures.     

A comparison of Escherichia coli levels at four sampling sites on turkey carcasses

The objective of this study was to investigate the levels of Escherichia coli on different sites of turkey carcasses by sponge sampling using a 50 cm2 template. The breast, thigh, back, and cavity sites were sampled to determine which sites would be suitable for quantifying E. coli levels for the purpose of assessing control of the slaughtering and chilling processes. Results show that the breast and cavity sites have the lowest levels of E. coli (2.6 and 2.7 cfu/cm2, respectively), whereas thigh and back sites have the highest (6.7 and 7.6 cfu/cm2, respectively). Data analyses indicate that E. coli levels at the breast and cavity site are lower (P < 0.05) than the other sites. A composite sample consisting of thigh and back sites for E. coli testing is recommended for assessing process control in turkey slaughtering facilities.     

Decrease of the incidence of sepsis syndrome after early enteral nutrition of patients with severe burns

The objective of this study was to evaluate the effect of early enteral nutrition on the incidence of the septic syndrome as well as its tolerance, in patients with severe burns. We retrospectively studied 64 patients older than 15 years of age, with a greater than 20% burned body surface area. They were divided into 2 groups as a function of the time elapsed between the beginning of Enteral Nutrition and the time of the burning: 23 patients were given Enteral Nutrition within 24 hours after the burn, and in 41 patients the enteral nutrition was started later than 24 hours after sustaining the thermal injury. Both groups were similar with respect to age, sex, percentage of 2nd and 3rd degree burns, incidence of inhalation, and deaths. All patients received the Enteral Nutrition through a nasogastric tube, with administration of a polymeric, hyperprotein and hypocaloric formula through a continuous infusion pump. In our study we saw a reduction of the incidence of the septic syndrome in the patients who received early enteral Nutrition (26%; 6 patients of a total of 23), with respect to those who did non receive early Enteral Nutrition (54%; 22 patients of a total of 41), with a statistical significance of p > 0.05. There were no differences between both groups with respect to the digestive tolerance to Enteral Nutrition. From our study we can deduce that early Enteral Nutrition reduces the incidence of septic complications, without this increasing the digestive intolerance to the same.     

Pharmacokinetics, safety, and activity of nevirapine in human immunodeficiency virus type 1-infected children

The challenge of useful serial photographic documentation of hair loss can be met by using a regimented approach at each photographic session. Patient outcomes that are better documented allow for more informed decisions to be made about the course of therapy by both the physician and the patient.     

Effects of frusemide on the urinary excretion of dopamine and 5-hydroxytryptamine in normal man

The effects of frusemide on the urinary excretion of dopamine and 5-hydroxytryptamine (5-HT) were investigated in eight healthy male subjects in a randomized, placebo-controlled, cross-over study. Frusemide produced the expected rise in urinary dopamine excretion but it did not affect 5-HT excretion when compared with placebo. The lack of an effect on 5-HT excretion in man contrasts with studies in the rat which have reported a marked increase in 5-HT excretion after administration of this loop diuretic.