Cigarette smoking increases white blood cell aggregation in whole blood.

We studied the effect of chronic cigarette smoking on white blood cell aggregation, increased aggregation predisposes to microvascular occlusion and damage. Current smokers had significantly increased white blood cell aggregation when compared with non smokers. The presence of chronically activated white blood cells in current smokers may be relevant in the pathogenesis of ischaemic vascular disease.     

Central nervous system site of action for the hypotensive effect of clonidine in the cat

The purpose of our study was to determine whether clonidine exerts its centrally mediated hypotensive action at three sites that influence arterial pressure located in the medulla, specifically associated with the intermediate area of the ventrolateral medulla. The "intermediate area" lies approximately 1.5 mm caudal to the border of the trapezoid body (caudal border) and 4 mm lateral to the midline. One of the sites that influence arterial pressure lies in the nucleus reticularis rostroventrolateralis. The second site lies in close proximity to the rostral part of the nucleus reticularis lateralis (rLRN) and also near the A1 area. The third site lies in the most rostral area and medial to the nucleus reticularis rostroventrolateralis, that is in the nucleus paragigantocellularis lateralis. Unilateral microinjections of 0.22 and 0.43 nmol of clonidine into the rLRN produced dose-dependent decreases in arterial pressure. The 0.43 nmol dose of clonidine had no effect when unilaterally or bilaterally microinjected into either the nucleus reticularis rostroventrolateralis or into the nucleus paragigantocellularis lateralis. Microinjection of the alpha-2 adrenoceptor antagonist, idazoxan (16.6 nmol), unilaterally into rLRN had no effect per se, but prevented the hypotensive effect of a subsequent microinjection of clonidine. Similarly, bilateral microinjection of idazoxan into rLRN counteracted the hypotensive effect of i.v. administered clonidine. These data indicate that clonidine acts at alpha-2 adrenoceptors in the rLRN to produce hypotension.     

Seniors' assessment of their health and life satisfaction: the case for contextual evaluation.

Health care professionals have been puzzled by the highly positive statements on health and life satisfaction made by seniors, particularly when compared to professionally collected data. In 1987-1988, a stratified, random sample of 520 seniors living independently in the community (70-99 years) were interviewed in their own homes. The above response pattern again held. However, it was apparent that opinions on life satisfaction vary with type of health problem. Content analysis of the spontaneous remarks made by the participants indicates that the overall, current, and anticipated levels of satisfaction expressed were associated significantly with the historical perspective or lifeview of the participants, and with their state of health. Utilizing the theoretical concept "sense of coherence" gives direction to understanding these phenomena.     

Neuropsychological and biomedical assessment of depression-dementia syndromes

Evaluating the clinical significance of cognitive dysfunction in patients who exhibit signs of both depression and dementia is one of the more formidable challenges in psychiatry. This article reviews cognitive dysfunction associated with depression, the concept of "pseudodementia," and the syndromal phenomenology of coexisting depression and Alzheimer's-type dementia. The state of the art in neuropsychologic, electroencephalographic, metabolic, and neuroradiographic techniques for evaluating dementia and depression syndromes will be discussed, as will implications for the treatment of such patients.     

Immunosuppression with cis-Platinum (II) Diammino-dichloride: Effect on Antibody Plaque-Forming Spleen Cells

A new antitumor compound, cis-platinum (II) diamminodichloride, suppressed antibody plaque-forming cells in C(3)H mice when given in a single dose of 10 mg per kg of body weight within 2 days before or after sensitization.     

Selection of biomaterials for peripheral nerve regeneration using data from the nerve chamber model

Peripheral nerve regeneration has been studied in a variety of animal models. Of these, the nerve chamber model has clearly dominated. It has been used to generate a large base of data that, however, cannot be analyzed usefully due to lack of standardization of experimental conditions and assays. Lack of standardization of critical experimental parameters of the model has, however, greatly limited the opportunity to compare directly data from independent investigators; as a result, progress in understanding conditions for optimal nerve regeneration has been stunted. In this article, we provide an overview of the major experimental parameters that must be controlled in order to generate data from independent investigators that can be compared directly (normalized data). Such parameters include the gap length, animal species, and the identity of assays used to evaluate the product of the regenerative process. Use of the recently introduced concept of critical axon elongation, the gap length at which the probability of axonal outgrowth (reinnervation) across the gap is 50%, leads to generation of a normalized database that includes data from several independent investigators. Conclusions are drawn about the relative efficacy of the various biomaterials and devices employed. Nerve chamber configurations that had the highest regenerative activity were those in which the tube wall comprised collagen and certain synthetic biodegradable polymers rather than silicone, and was cell-permeable rather than protein-permeable. In addition, the following tube fillings showed very high regenerative activity: suspensions of Schwann cells; a solution either of acidic or basic fibroblast growth factor; insoluble ECM substrates rather than solutions or gels; polyamide filaments oriented along the tube axis; highly porous, insoluble analogs of the ECM with specific structure and controlled degradation rate.     

Relative carriage rates of nuclear dehydrogenating clostridia in two populations of different colorectal cancer risk

Carriage of nuclear dehydrogenating clostridia has been associated with colon cancer and implicated in its aetiology. This study has compared the carriage of these organisms in a British population at high risk for the development of colon cancer with a low risk Nigerian population. Clostridia were found in all of the stools from both populations. Nuclear dehydrogenating clostridia were only found in the stools of the British subjects (32%). These results support the suggestion that the carriage rate of nuclear dehydrogenating clostridia in a population is related to the risk of colon cancer.