Structural and histochemical features of the avian blood-brain barrier

We have investigated the structural and histochemical features of the blood-brain barrier (b-bb) in both adults and embryos of chicken (Gallus domesticus, White Leghorn) and quail (Corturnix coturnix japonica). We found that brain endothelial cells of both species are characterized structurally by tight junctions, a low density of pinocytotic vesicles, and a moderately elevated density of mitochondria. Both alkaline phosphatase and butyryl cholinesterase were found in adult quail brain capillaries, but only alkaline phosphatase was found in adult chick brain capillaries. Aromatic amino acid decarboxylase was not found in brain capillaries of either species. In the chick embryo alkaline phsophatase appeared during the time when b-bb matures functionally; i.e., during the third week of development. However, an elevation in mitochondrial density was not apparent until after hatching. In the quail, alkaline phosphatase and butyrl cholinesterase appeared during the last week of embryonic development. By 2 days posthatching the structural characteristics of the brain capillaries were similar to those in the adult.     

Fibre type characteristics of the lumbar paraspinal muscles in normal healthy subjects and in patients with low back pain

A knowledge of the alteration in the fibre type profile of paraspinal muscle associated with low back pain is essential for the design of successful rehabilitation programmes. In attempting to compare the muscles of patients with low back pain with those of controls, few previous studies have considered factors such as gender, age, and size of the subjects, each of which can potentially confound interpretation of the results. We obtained samples of lumbar paraspinal muscle during spinal surgery from 21 patients with low back pain and, using the percutaneous biopsy technique, from 21 control volunteers matched for gender, age, and body mass. The samples were subject to routine histochemicsl typcal analysis to determine characteristics of muscle fibre type. Compared with controls, the muscle of the patients had a significantly higher proportion of type-IIB (fast-twitch glycolytic) fibres than type- I (slow oxidatve) fibres. The mean size of a given fibre type did not differ between the patients and the controls. Consequently, the relative area of the muscle iccupied by type-IIB fibres was higher and that by type-I fibres Was lower in the patients. The patients had a greater number of muscle samples with more than 1% type-IIC fibres, and abnormalities that could be described as pathological were more marked in the patients than in the controls. In conclusion, the paraspinal muscles of patients who have low back pain display a more glycolytic (faster) profile; this can be expected to render them less resistant to fatigue.     

Breast Cancer Genes

Abstract: The identification of familial breast cancer genes heralds an era of directed breast cancer treatment. Currently, two hereditary breast cancer genes have been identified, BRCA-1 and BRCA-2 . Although accounting for only approximately 5% of all breast cancers, they are being used to identify women with germ-line alterations that are at high risk of developing breast or ovarian cancer. With the identification of such genes comes a need for consideration of the ethical issues associated with testing. These genes are also being examined from a biochemical standpoint encompassing both their biological roles and biochemical pathways in which they reside. Such studies are likely to lead to novel breast cancer therapies.     

The effects of menstrual phase and nicotine abstinence on nicotine intake and on biochemical and subjective measures in women smokers: a A preliminary report

Nicotine intake, menstrual and smoking withdrawal symptomatology, and baseline cortisol and MHPG were assessed in nine women smokers under conditions of ad lib smoking and overnight abstinence in three menstrual phases (early follicular, mid-to-late follicular, and late luteal). A trend towards higher nicotine intake p <0.100 was observed in the mid-to-late follicular phase. Although me menstrual symptomatology was not significantly elevated during the smoking abstinence condition overall, abstinence appeared to prevent the normal reduction in symptomatology during the mid-to-late follicular phase that occurred under conditions of ad lib smoking. Menstrual and withdrawal symptoms were highly correlated, and both were most pronounced during the late luteal/abstinence condition. The smoking-specific item “craving” reflected this pattern, though in attenuated form, suggesting that the observed exacerbation of withdrawal symptomatology was not simply due to generalized dysphoria, as queried in both instruments. MHPG was significantly elevated in the late luteal phase, whereas cortisol was significantly higher during ad lib smoking than during abstinence and tended to be highest in the mid-to-late follicular phase. Further investigation will be needed to determine the functional significance of these findings for understanding and treating smoking in women.     

Correlates of cognitive dysfunction in an ambulatory elderly population

Mini-Mental State Examination (MMSE) scores were studied in an ambulatory elderly population to identify correlates with self-reported signs, symptoms, diseases, drugs and laboratory values. A total of 1,264 subjects were studied including 844 women and 420 men. In this study, 5.0% of men and 5.3% of women scored less than 24 on the MMSE. A linear-regression model revealed eleven factors of significance in predicting scores on the MMSE. The most important predictors were age (p less than 0.0001), self-reported memory loss (p less than 0.0001), complaints of swollen feet or ankles (p less than 0.0010), the total number of diseases reported (0.0006) and the serum lactate dehydrogenase concentration (p less than 0.0098). Results suggest that cognitive function in the elderly is not related to the general level of health or consistently affected by specific disease states.     

Nitric oxide synthase inhibitor,nitro-iminoethyl-L-ornithine,reduces ischemia-reperfusion injury in rabbit skeletal muscle

Nitric oxide (NO), originally identified as the mediator of endothelial-dependent relaxation of vascular smooth muscle, is now known to also have cytotoxic effects under certain conditions. Thus, we have investigated the effects of inhibition of NO synthesis on ischemia/reperfusion injury in the rabbit rectus femoris muscle. Three and a half hours of ischemia and 24 hours of reperfusion resulted in a 56% loss of viability. In muscles receiving an infusion of the nitric oxide synthase inhibitor, L-NIO (30 μM), the loss of viability was reduced to 15%. Post-ischemic blood flow was increased in muscles receiving a saline infusion, whereas there was a marked decrease in blood flow for at least the first 60 minutes of reperfusion in muscles treated with L-NIO (30 μM). The increase in myeloperoxidase levels (indicative of neutrophil accumulation) following 24 hours of reperfusion was attenuated with L-NIO infusion by approximately 50% and the reperfusion-induced edema was also attenuated in L-NIO treated muscle. These findings suggest that endogenous NO production during ischemia/reperfusion injury may be deleterious to muscle survival. © 1994 Wiley-Liss, Inc.