Locomotor activity and catecholamine receptor binding in adult normotensive and spontaneously hypertensive rats

Summary The binding of³H-WB 4101, an ₁-adrenoceptor antagonist, to membranes of the cerebral cortex, the hypothalamus, and the lower brainstem was examined in adult spontaneously hypertensive (SH) rats and in normotensive Wistar Kyoto (WK) controls. The specific binding of³H-WB 4101 (0.33 nM) was significantly higher in homogenates from the cerebral cortex of SH rats as compared to WK rats. No differences were detected between SH and WK rats in the specific binding of³H-spiroperidol (0.25 nM), a dopamine receptor antagonist, to membranes from the corpus striatum and the limbic forebrain. The locomotor activity was significantly higher in SH rats as compared to WK controls, in all probability due to a lack of habituation to environmental change. It is suggested that the high reactivity of SH rats is related to a dysfunction in the noradrenergic neurons in the central nervous system.     

Research approaches in health professions education: problems and prospects

Research in health professions education has been dominated by a research paradigm emphasizing controlled experimentation. Widespread criticism has been voiced by leaders in the research community concerning the adequacy of the paradigm to deal with complex human behavior occurring in complex social environments. This article is concerned with exploring the implications of controlled studies for health professions education and proposing an alternative research strategy.     

Quantitative analysis of a licensing examination using adverse impact

Does licensure restrict entry fairly, or does it serve as a discriminatory barrier for minorities? The use of the concept of adverse impact, a legally mandated, quantitative tool to assess selection procedures, is a useful mechanism to make such determinations. The results of a study in Michigan of the nursing examination for licensure show how adverse impact may be used. The implications of the outcome of the adverse impact study weigh heavily not only on the nursing examination but also on the use of such tools in other health professions.     

Combined chemotherapy-radiotherapy study of small cell bronchial carcinoma: chemo-/radiotherapy vs radio-/chemotherapy

The authors studied the effect of a chemo-/radiotherapy or radio-/chemotherapy on 52 cases of microcellular bronchial carcinoma, classification "limited disease". The survival curves were slightly better for the patients submitted to primary chemotherapy, but the difference was not statistically significant, and the curves coincided again after 18 months. 60 to 80% of the patients had no complaints or only unimportant complaints during more than half of their survival time. In 23 patients with "extensive disease" who received only a symptomatic therapy or a combined palliative chemotherapy, chemotherapy had a slightly better effect, but this was not statistically significant.     

The effect of bipolar electrosurgical coagulation waveform on a rat uterine model of fallopian tube sterilization

Laparoscopic bipolar electrosurgical sterilization has been employed for nearly two decades. This bipolar procedure was intended to reduce the incidence of unintended complications, such as bowel burns. However, compared to the monopolar procedure, it produced a higher failure rate. This study examines the role of the low power-high voltage coagulation waveform on the effectiveness of electrosurgical desiccation on the rat uterine model of the fallopian tube. Desiccations were performed with both Kleppinger and Storz forceps using generator settings from 2 to 6. Desiccations performed to the visual endpoint (blanch, swell, and collapse) required from 23.8 to 30.0 joules, although procedures performed at a generator setting of 2 required long application times, an average 15.4 sec (Storz) and 28.2 (Kleppinger). All bipolar procedures led to a loss of tissue at the desiccation site at 12 weeks postsurgery. Therefore, the electrosurgical coagulation waveform proved to be effective in producing adequate in vivo tissue destruction even at very low generator settings.     

Expression of 65-kd heat shock proteins in the inflammatory myopathies.

In normal muscle, 65-kd heat shock proteins (hsp) were detected on capillary endothelial cells, the mural elements of larger vessels, and some intracellular organelles, probably mitochondria. In the inflammatory myopathies, the 65-kd hsp were detected on inflammatory cells, degenerating and regenerating fibers, and on many but not all nonnecrotic muscle fibers invaded by T cells. The expression of the 65-kd hsp may be an immune-nonspecific response to cellular "stress," but hsp determinants could possibly also serve as autoantigen(s) recognized by autoreactive T cells.     

AlphaB-crystallin immunolocalization yields new insights into inclusion body myositis

OBJECTIVE: To study the expression of the small heat shock protein, alphaB-crystallin (alphaBC), in inclusion body myositis (IBM). BACKGROUND: In humans, alphaBC is constitutively expressed in the eye lens, muscle, and heart, but not in lymphoid tissues. Induced expression of alphaBC occurs under metabolic stress, in virus-infected lymphocytes, and in degenerative brain lesions, including neurofibrillary tangles and senile plaques in AD. The previously reported pathologic similarities between AD and IBM prompted us to study alphaBC expression in IBM. METHODS: Immunolocalization of alphaBC in muscle of 11 patients with IBM, 50 patients with other muscle diseases, and 4 controls; and quantitative analysis of the frequency of fibers with 1) increased alphaBC expression in IBM and polymyositis and 2) structural abnormality (vacuolated, non-necrotic and invaded by mononuclear cells, Congo red-positive, SMI-31 positive, and ubiquitin positive) in IBM. RESULTS: We detected enhanced expression of alphaBC not only in all structurally abnormal IBM fibers, but also, and with severalfold higher frequency, in IBM fibers without significant structural abnormality (X fibers) (p values in paired t-tests < 0.001). We also found enhanced alphaBC in abnormal fibers in other diseases; X fibers, however, were extremely sparse or absent, except in two atypical cases of polymyositis refractory to immunotherapy. CONCLUSION: That the X fibers are much more frequent than the structurally abnormal fibers in IBM points to a pathogenic stressor acting upstream to the development of structural abnormalities. The identification of this stressor is now of paramount importance for deciphering the enigma of IBM.