Changes in mammary tissue lipid metabolism in the goats during the first 2 months of lactation]

5 French Alpine Goats were studied after normal or premature parturition. Mammary tissue acetyl-C oA carboxylase, glucose-6-phosphate dehydrogenase, malic enzyme and lipoprotein lipase (LPL) activities varied in parallel with milk fat secretion from the 3rd to the 9th week of lactation. Variations of mammary LPL activity and of long chain fatty acid secretion were positively highly correlated during that period. In goats with normal parturition, lipogenic activities seemed to reach a maximum level shortly after parturition. There was a positive correlation between mammary Ll activities and plasma non esterified fatty acid contents, possibly reflecting a relationship between adipose tissue mobilisation and mammary metabolism.     

Hypertrophy of pulmonary arteries and arterioles with cor pulmonale in rats induced by seneciphylline,a pyrrolizidine alkaloid

Summary Seneciphylline, one of the hepatotoxic pyrolizidine alkaloids, induced, as do also monoclotaline, etc., a marked arterial and arteriolar hypertrophy of the lung of young Wistar rats a month after a single s. c. injection of 50–80 mg/kg. Cor pulmonale with leftward shift of the ventricular septum was also noted.     

Inhibitory effect of exogenous histones on cellular growth and DNA synthesis in Chlamydomonas reinhardtii.]

The addition of exogenous histones to synchronous culture of Chlamydomonas reinhardtii, at the beginning of the cell cycle, leads to the death of the cells. The same amount of histones added in the middle of the cycle, only blocks the cell division. The mechanism of this inhibition effect of the histones could involve a block at the level of the chloroplast DNA replication.     

Effect of the type of diet on the distribution of 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase in rat small intestine

Summary The jejunoileal gradient for the HMG-CoA reductase activity in the microsomal fraction of the epithelial cells of the small intestine of rats given commercial pellets was reserved within a few days after changing the ration to a semipurified diet. The response of the reductase was essentially the same in villus and crypt cells.     

Local aggregation of hormone-receptor complexes is required for activation by epidermal growth factor.

An analogue of epidermal growth factor (EGF) which is virtually devoid of biological activity retains receptor binding activity but cannot form cell surface clusters or patches. Bivalent anti-EGF antibodies restore both bioactivity and patch formation. The sensitivity of fibroblasts to native EGF can also be enhanced greatly by these antibodies, especially in hormone-resistant cell lines.     

Persistence of orientation-selective cells of the primary visual cortex in kittens enucleated unilaterally at birth and reared in darkness]

In kittens dark reared (6 weeks old) orientation selective cells are no longer recorded in the primary visual cortex, while in kittens of same age, enucleated at birth unilaterally and reared in identical conditions, 30% of visual cortical cells are shown to be orientation selective and in addition respond preferentially to horizontal and vertical orientations.     

Unusually strong lipophilicity of ‘fat’ or ‘super’ amino-acids,including a new reference value for glycine

Summary Lipophilic, steric, electronic, and enzyme resistance characteristics of carboranylalanine, adamantylalanine, neopentylglycine and tert-butylglycine are described. The first 2 amino-acids display lipophilicities 2 orders of magnitude higher than tryptophan.This work was supported by research grants to Prof. R. Schwyzer from the Swiss National Science Foundation.