A probable new pathway for the biosynthesis of putrescine in Escherichia coli.

Some cultures of Escherichia coli BGA8, a mutant unable to synthesize putrescine, showed a change of behaviour and could grow almost equally well in either the absence or the presence of polyamines after repeated periods of polyamine starvation. Experiments in vivo with radioactive precursors showed that the bacteria which evaded the polyamine requirement had recovered their ability to synthesize putrescine from glucose or glutamic acid, but not from ornithine or arginine. These results are in agreement with the fact that the polyamine-independent cells were still deficient in the enzymes ornithine decarboxylase and agmatinase.

Positive inotropic effects of ibopamine in patients with congestive heart failure. A multicenter investigation.

A multicenter double-blind placebo-controlled investigation was carried out in 42 patients with severe congestive heart failure who were given ibopamine (SB-7505), the 3,4-diisobutyryl ester of N-methyldopamine, for a period of 10 days in addition to previous treatment with digitalis and diuretics. Symptoms were evaluated by using a suitable score; some patients were submitted to an exercise test along with other clinical tests. Compared with placebo, ibopamine induced no significant changes in heart rate and arterial blood pressure.

[Characterization of the convoluted seminiferous tubule wall. I. Ultrastructural aspects after the ligation of the vas deferens and the efferent tubules].

The structure of the wall of the rat seminiferous tubules has been studied by electron microscopy. No significant modifications have been revealed after the ligature of the vas deferens while on the contrary the ligature of the efferent ductules produces a reduction of the contractile filaments and of the pinocytosis vesicles, as well as an increase of the amount of collagen fibers in the basal membrane.