Predicting cerebral ischemia during carotid endarterectomy

We reviewed 86 consecutive patients undergoing elective carotid endarterectomy to determine whether preoperative clinical and angiographic data could be used to predict the risk of intraoperative cerebral ischemia during carotid occlusion. Electroencephalographic (EEG) monitoring with on-line Berg-Fourier transformation was carried out in all patients. A total of 32 patients (37.2%) underwent intraoperative shunting. Of these, 13 had no EEG changes but underwent shunting because of the surgeon's preference, while 19 patients underwent shunting because of EEG changes consistent with cerebral ischemia. There was one permanent (1.2%) and one transient (1.2%) neurologic deficit. Angiographic findings, clinical histories, and intraoperative EEGs were retrospectively reviewed to determine which risk factors best predicted the occurrence of intraoperative cerebral ischemia. Stroke within six weeks increased the risk of intraoperative cerebral ischemia 20-fold. Intracranial disease and contralateral carotid stenosis increased the risk of ischemia 17-fold and 16-fold, respectively. Statistical summation of all risk factors yielded a probability equation for EEG change that accurately quantitated pre-operative risk. Prospective application of this probability equation may simplify operative decision making if EEG monitoring is not available.     

Activity of some naphthoquinones on blood stream forms of Trypanosoma cruzi

Accidental transmission of Chagas disease to man by blood transfusion is a serious problem in Latin America. This paper describes the testing of several naphthoquinones, some of which were active against blood trypomastigotes in vitro at 4 degrees C and might therefore warrant further study for preventing transmission of Chagas disease by blood transfusion.     

Stress selectively influences center region activity of mice in an open field

Effects of immobilization and footshock stress on locomotor activity in different areas of an open field were examined in mice. Center region activity, peripheral region activity and total activity were used as measurement indices. These results indicate that both immobilization and footshock stress significantly increased total activity across 24 min of behavioral testing. Further analyses revealed that the difference in total activity between the experimental and control groups were mainly attributal to an increase in center region activity. Both stress manipulations markedly augmented peripheral region activity for only the first 6 min. More important, when the proportion of center to peripheral activity was used as an index, both experimental groups manifested an inverted U shape relationship with the maximum effect occurring between 13-18 min of behavioral testing. Similarities of these activity measures in response to different stressors suggests that common neurochemical and/or neurohormonal mechanisms may mediate these behavioral changes.     

Histopathology in tropical medicine: a perspective

Histopathology may serve a wide spectrum of diagnostic purposes in tropical medicine other than for infectious and parasitic diseases. In addition, it is essential in defining new pathological entities and collecting statistical data on morbidity and mortality. It should also constitute a basic support for advancement and research in tropical diseases. For practical purposes, both histopathology and cytopathology are often more effective than clinical chemistry and microbiology in providing the clinician with a final diagnosis. They do not rely on complicated and delicate equipment, and the few reagents they require can be stored indefinitely. Formalin fixation permits most histological methods to be used, including special stains and immunohistochemistry. Formalin-fixed material can be examined several days after excision. Implementing pathology laboratories in tropical countries may constitute a practical, cost-effective approach to the planning of diagnostic services at the regional or district level. A fraction of the medical graduates in developing countries should be devoted to the staffing of these laboratories.     

Carotid surgery in stroke prevention

Extracranial carotid disease accounts for up to 50 percent of strokes. Transient ischemic attacks are associated with a 30 to 35 percent risk of stroke within five years of the initial episode. Carotid endarterectomy is a safe and effective way of reducing the risk of stroke in patients with TIAs. It is also helpful in patients with amaurosis fugax, and may benefit selected patients with acute stroke or those with asymptomatic but hemodynamically significant stenosis.     

Further evidence of preserved memory function in Alzheimer's disease

Memory performance of elderly patients in the early stages of Alzheimer's disease (DAT) was compared with that of elderly control subjects. In explicit tests of recognition memory, which involve conscious recollection, the DAT patients were grossly impaired. In implicit tests of anagram solution and wordstem completion, which do not require conscious recollection, the DAT patients were not impaired. These findings further support the idea that a separate memory system, episodic memory, underlies conscious recollection, that it is this system which is most commonly damaged in amnesia, and that memory systems not involving conscious recollection may be spared in the early stages of Alzheimer's disease.