Persistence of coitus during induced infertility in male rats.
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Biomedical subjects
Publications and source records attributed to R S Ho.
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The present studies were undertaken to investigate the possible mechanism(s) of action of 2,2-dimethyl-1-(4-methylphenyl)-1-propanone (SaH 50-283) on food efficiency in rats. SaH 50-283, unlike phenformin (DBI), did not inhibit glucose absorption. However, hyperglycemia induced by oral maltose, lactose or starch load was markedly inhibited in animals pretreated with SaH 50-283. The ED25 for lowering blood sugar levels following an oral maltose load was calculated to be 12 mg/kg. SaH 50-283 could be administered as long as 7 hr prior to a maltose load and still maintain its effect. Food efficiency was significantly (P less than .01) lowered in rats pretreated with SaH 50-283 1 hr prior to a 2 hr feeding period of a purified high carbohydrate diet. It was concluded that the lowering of maltase activity in the brush border of animals treated with SaH 50-283 could partially account for its mechanism of action in lowering food efficiency in rats.
Evidence suggests that in humans tuberculous disease usually arises at apical or subapical sites in the lungs seeded as a consequence of an early bacillemic phase of the infection. This study examined the fate of bacilli transported via the bloodstream to metastatic sites in the lungs of guinea pigs after aerosol infection with approximately two viable virulent Mycobacterium tuberculosis. The results revealed that, even after logarithmic-phase multiplication of bacilli in primary lesions had been terminated, bacilli seeded via the bloodstream to metastatic sites in the lung were able to multiply. These observations, made in an animal model that mimics the conditions under which tuberculosis develops in human subjects, challenge the relevance of systemic macrophage activation in experimental airborne tuberculosis in guinea pigs.