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.     

Occurrence of thiaminase II in Saccharomyces cerevisiae

It was found that cell-free extracts of Saccharomyces cerevisiae contain thiaminase II which hydrolyzes thiamine and thiamine analogs. The possible involvement of this enzyme and thiamine-synthesizing enzymes in thiamine production from thiamine antagonists is discussed.     

Protein kinase C injection into hippocampal pyramidal cells elicits features of long term potentiation

Long-term potentiation (LTP) in the hippocampus is an interesting example of synaptic plasticity because of its induction by physiological discharge rates and its long duration. Of the possible biochemical mechanisms that regulate prolonged changes in cell function, protein phosphorylation is a particularly attractive candidate. We have therefore examined the effect of intracellular injection of calcium/diacylglycerol-dependent protein kinase (protein kinase C (PKC] in CA1 pyramidal neurones in hippocampal slices. Injection of the active enzyme elicited long-lasting enhancement of synaptic transmission, similar to LTP, whereas inactivated kinase failed to do so. The observed changes included an increased amplitude of the excitatory post-synaptic potential (e.p.s.p.) and an increased probability of firing and a reduced latency of the associated actin potential.     

Effects of chloroiodoquine and lethal doses in various mouse strains]

Chloroiodoquine has been implied in numerous cases of myeloneuropathy in Japan, while in other countries although equally frequently used, only a few cases have been reported after treatment with this drug. Studies on the effect of chloroiodoquine in mice of various inbred strains or from crossings between sensitive and insensitive strains demonstrated a genetic predisposition of sensitivity to chloroiodoquine.