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OBJECTIVE: Smoking is a major public health problem. The doctor should be at the forefront in the fight against tobacco. Our study aims to determine the prevalence of smoking among medical students and to evaluate their attitudes towards this problem. PATIENTS AND METHODS: A cross-sectional survey was conducted among 736 medical students enrolled in the faculty of medicine and pharmacy of Casablanca in the academic year 2009/2010. RESULTS: The prevalence of smoking was 7.9%. It was significantly higher in men (16% against 3% in women) and varied little from one age group to another (7-8%). The average number of cigarettes smoked per day was eight. More than half of the students (58%) had attempted to quit smoking. The main motivation was the occurrence of certain symptoms (66%). Ex-smokers accounted for 10% of the total. Moroccan anti-smoking law was poorly understood by more than half of our students (72%). The majority was in favor of prohibition of tobacco sales to children (92%) and the training of health professionals to help patients who want to quit smoking (86%). CONCLUSION: Compared with previous years this study shows a marked decrease in the prevalence of smoking among medical students in Casablanca as well as a better understanding of its ill effects. This is due not only to greater awareness of this problem among medical students but also to the introduction of the teaching of the pathologies related to tobacco.

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Kuwaiti diet is exceptionally rich in fat, carbohydrates and proteins. In addition, subjects in Kuwait are exposed to extreme heat and sun light. Fatty acid profiles of human milk obtained from 19 full breast feeding Kuwaiti mothers were analyzed. Dietary patterns for individual mothers were determined by 24 h dietary recall and food frequency questionnaire. The fatty acid content of human milk was affected by the diet consumed by the lactating mother. The content of long chain polyunsaturated fatty acids (LCP) in human milk lipids did not correlate with their parent fatty acids like linoleic and alpha-linolenic acids. However the human milk LCP were related to the of content of LCP in the maternal diet. Mothers reporting a high fish consumption showed significant amounts of C22:6, omega 3 and C20:5, omega 3 fatty acids. As a general conclusion, breast milk produced by a well nourished mother is better suited to meet the lipid requirements of infants.

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Hepatocellular carcinoma were recognized in the toad, Bufo viridis, in 14 cases out of 50 by injection of 1 mg 7,12 dimethylbenz(a)anthracene (DMBA)/toad twice/week for 12 weeks. In contrast, toads treated with DMB at the same dose level and beta-carotene (betaC), 0.05 mg (3 hr prior to the carcinogen)/toad, twice/week for 12 weeks showed no tumor incidence. However, betaC at the same dose level was less effective when administered 3 hr. after the carcinogen (DMBA). In 8 cases out of 50 cases neither tumor growth nor neoplastic changes were observed in toads treated with betaC alone or olive oil. It is concluded that betaC completely blocked hepatocarcinogenesis in toads when given 3 hr. before initiation.

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Drinking of both green and black tea as the only liquid ingested resulted in significant decreases in the activity of transketolase in whole blood of rats both before and after the in vitro addition of thiamin diphosphate. Liver transketolase activity was decreased only by green tea. Mucosal transketolase activity was not affected by either type of tea. The activity of lactate dehydrogenase (LDH) was not affected by either type of tea, while whole blood LDH was decreased by both green and black tea. Neither tea had any affect on mucosal alkaline phosphatase, but thiamin diphosphatase activity was decreased by both teas. An increase in liver total thiamin resulted from the drinking of both types of tea.

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Rat heart mitochondria became permeabilized to sucrose when incubated with 100 nmol of Ca2+/mg of protein in the presence of Pi. Ca2+ chelation with EGTA restored impermeability to sucrose, which became entrapped in the matrix space. t-Butylhydroperoxide markedly promoted permeabilization in the presence of Ca2+ but not in its absence, and Ca2+-plus-t-butylhydroperoxide-induced permeabilization was reversed by EGTA. The data suggest that Ca2+ and oxidative stress synergistically promote the reversible opening of an inner membrane pore.

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The technique of reversible Ca2+-induced permeabilization [Al Nasser & Crompton (1986) Biochem. J. 239, 19-29, 31-40] has been applied to the preparation of heart mitochondria loaded with the Ca2+ indicator arsenazo III (2 nmol of arsenazo III/mg of mitochondrial protein). The loaded mitochondria ('mitosomes') were used to study the control of the Na+-Ca2+ carrier by extramitochondrial Ca2+ mediated by putative regulatory sites. The Vmax. of the Na+-Ca2+ carrier and the degree of regulatory-site-mediated inhibition were similar to normal heart mitochondria. Ca2+ occupation of the sites in mitosomes yields partial inhibition, which is half-maximal with 0.8 microM external free Ca2+. The inhibition consists of a small decrease in Vmax. and a relatively large increase in apparent Km for internal Ca2+. Mg2+ also appears to interact with the sites, but this is largely abolished by ATP and ADP (but not AMP) under conditions in which the free [Mg2+] is maintained constant. The results indicate that the regulatory sites are effective in controlling the Na+-Ca2+ carrier at physiological concentrations of adenine nucleotides, Mg2+, intra- and extra-mitochondrial free Ca2+.

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The interaction of trifluoperazine and extramitochondrial Ca2+ with the heart mitochondrial Na+-Ca2+ carrier has been investigated. External Ca2+ inhibits the carrier equally in mitochondria and mitoplasts in which the outer membrane is lysed. Sensitivity to Ca2+ is not removed by washing mitoplasts under varied conditions. Trifluoperazine is a potent inhibitor of the carrier in mitoplasts but not in mitochondria. Trifluoperazine inhibition in mitoplasts depends markedly on the presence of extramitochondrial Ca2+ (2 microM).

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The Na+-induced efflux of Ca2+ catalysed by the Na+/Ca2+ carrier of cardiac mitochondria is strongly inhibited by extramitochondrial Ca2+. The nature of this inhibition was investigated as follows. (a) The apparent association of external Na+ and the Ca2+ analogue Sr2+ with substrate-binding sites (i.e. those sites involved in cation translocation) is promoted markedly by K+. The inhibition of Na+/Ca2+ exchange by external Ca2+ is affected little by K+. (b) There is a competitive relationship between the binding of external Na+ and external Ca2+ to substrate-binding sites, whereas at low concentrations (less than 4 microM) extramitochondrial Ca2+ is a partial non-competitive inhibitor with respect to external Na+. (c) This inhibiton by external Ca2+ is characterized by a maximal decrease of about 70% in the Vmax of Na+/Ca2+ exchange and by cooperative binding of external Ca2+ to sites that are half saturated by 0.7-0.8 microM free Ca2+. The binding of Ca2+ and Sr2+ to substrate-binding sites shows no co-operativity. These criteria suggest that the Na+/Ca2+ carrier may contain regulatory sites that render the carrier sensitive to changes in extramitochondrial [Ca2+] within the physiological range.

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