The effects of hyponatraemia and subarachnoid haemorrhage on the cerebral vasomotor responses of the rabbit

Impairment of cerebral autoregulation and development of hyponatraemia are both implicated in the pathogenesis of delayed cerebral ischaemia and infarction following subarachnoid haemorrhage (SAH) but the pathophysiology and interactions involved are not fully understood. We have studied the effects of hyponatraemia and SAH on the cerebral vasomotor responses of the rabbit. Cerebrovascular reactivity to hypercapnia and cerebral autoregulation to trimetaphan-induced hypotension were determined in normal and hyponatraemic rabbits before and 6 days after experimental SAH produced by two intracisternal injections of autologous blood. Hyponatraemia (mean plasma sodium of 119 mM) was induced gradually over 48 h by administration of Desmopressin and intraperitoneal 5% dextrose. Sham animals received normal saline. The cerebrovascular reactivity (% change +/- SD in cortical CBF/mm Hg PaCO2, measured by hydrogen clearance) of hyponatraemic (4.8 +/- 3.0%) and SAH (1.3 +/- 2.0%) animals was significantly less (p less than 0.05) than control (11.6 +/- 4.0%) and sham (8 +/- 2.0%) animals, whereas the reactivity of hyponatraemic-SAH animals was preserved (9.8 +/- 6.0%). Hyponatraemia and SAH alone each significantly impaired CBF autoregulation but their combined effects were not additive. Systemic hyponatraemia impairs normal cerebral vasomotor responses but does not augment the effects of experimental SAH in the rabbit.     

Administration of kainic acid and colchicine alters mu and lambda opiate binding in rat hippocampus

Quantitative in vitro autoradiography was used to assess the effects of kainic acid (KA) and colchicine (COL) on mu and lambda opiate binding in the rat hippocampus. Rats were treated with either systemic KA, a neurotoxin that damages CA3 pyramidal cells and causes seizures and wet-dog shakes, or intrahippocampal COL to destroy dentate granule cells and their mossy fibers, or both toxins. Moderate levels of mu binding were detected in the pyramidal layer and in the stratum lacunosum-moleculare; binding was greater in the ventral hippocampus. Levels of mu binding were markedly increased in all regions 48 h after treatment with KA. Two weeks after COL treatment, there was a modest decrease in mu binding; COL plus KA gave results similar to COL alone. Dense lambda binding was present over the mossy fibers in the stratum lucidum, but was absent over the pyramidal layer. In contrast to mu binding, lambda binding was greater in the dorsal hippocampus. KA alone had little effect on lambda binding, whereas COL alone caused large decreases. KA plus COL caused even larger decreases in lambda binding, to as much as 85% below control. These results demonstrate that mu and lambda binding are localized to different parts of the hippocampus, respond differently to neurotoxin lesions, and likely serve different roles in this brain region. The number of mu sites is responsive to the release of enkephalin; these receptors appear to be linked to opiate-induced hippocampal seizure activity, especially wet-dog shakes. Lambda sites may serve as autoreceptors on mossy fibers.     

Results of prevention programs with adolescents

Programs for preventing smoking and alcohol and drug abuse have radically changed in the past decade. Instead of being regarded as a health or discipline problem that involves only a few deviant adolescents, drug use has begun to be viewed as social behavior that is functional for adolescents, not capricious, and is normative for that population. The most successful prevention programs have sought to delay the onset of tobacco use. Based on theoretical and etiological research, these programs target factors that have repeatedly been predictive of adolescent smoking, alcohol and drug use. The programs teach adolescents (1) why people their age smoke tobacco or use alcohol and drugs; (2) how these meanings get established by peers, older role models and advertising; (3) how to resist these influences to smoke or to use alcohol and drugs; and (4) life skills and competencies to counterbalance the functions that drug use serves. Because of the association with the onset of smoking and the onset of using other drugs, these strategies are being studied for alcohol use and other drugs. In addition, elected peer leaders are trained to conduct these activities with their classmates and act as new role models for non-use. Evaluations of these approaches are optimistic. Studies in northern California and Minnesota reveal 50-70% reductions in the onset of smoking. Botvin's 'Life Skills Training' program demonstrates success in delaying heavy alcohol and marijuana use.     

Costs and benefits of routine follow-up after curative treatment for endometrial cancer

OBJECTIVE: To examine the costs of routine outpatient follow-up after curative treatment of endometrial cancer, and to determine whether this leads to early detection of recurrence or survival. The impact of specific disease characteristics on survival is examined. DESIGN: Retrospective chart review, and calculation of costs. SETTING: Ottawa Regional Cancer Centre-Civic Division (ORCC-C). PATIENTS: All 432 patients referred to the ORCC-C with endometrial cancer between 1982 and 1991 who received treatment with curative intent and who continued with routine follow-up. RESULTS: Cancer recurred in 50 patients (11.57%). There was no statistically significant difference in overall survival between patients with symptomatic and asymptomatic recurrences, or between those with recurrences detected during routine follow-up visits or in the interval between routine visits. Of 4830 Papanicolaou (Pap) smears performed routinely, cancer was detected in 6 cases. The mean cost of the routine follow-up procedures for each patient with a recurrence was $19,200. CONCLUSION: Intensive follow-up of women with endometrial cancer does not result in improved survival. A prospective randomized study is warranted to evaluate other potential benefits of follow-up, such as improved quality of life or decreased morbidity. There is no economic or clinical justification for the routine use of the Pap smear in the follow-up of patients with endometrial cancer. The potential benefits of routine follow-up in endometrial cancer and other types of cancer with favourable prognoses warrant critical evaluation.