Liver enzymes of serine metabolism during neonatal development of the rat.

The developmental patterns of L-serine hydroxymethyltransferase, L-phosphoserine aminotransferase, L-serine aminotransferase and L-serine dehydratase were determined in rat liver. The results point to an increased capacity for serine biosynthesis de novo in the perinatal period. It is suggested that serine at this time, and also at weaning, may serve as a precursor, via the serine hydroxymethyltransferase reaction, for nucleotide biosynthesis to support the rapid phases of liver growth.

Role of exotoxin and protease as possible virulence factors in experimental infections with Pseudomonas aeruginosa.

Evidence is presented which suggests that both the proteases and the exotoxin produced by Pseudomonas aeruginosa multiplying in situ in a burned mouse model are virulence factors. A 50% decrease in functional elongation factor 2 (EF-2) was seen 16 h postinfection in the liver of mice infected with the toxigenic, protease-producing P. aeruginosa strain M-2; at the time of death EF-2 was depleted by 80%.

Glucose metabolism in the newborn rat: the role of insulin.

The effect of the administration of anti-insulin serum to newborn rats, surgically delivered under ether anaesthesia at term, was examined with respect to liver glycogen concentration and plasma concentrations of glucose, lactate and free fatty acids. Newborn rats thus treated showed decreased liver glycogen concentrations and elevated plasma concentrations of glucose, lactate and free fatty acids compared to untreated control animals one hour later. These effects were dose-dependent with respect to the amount of anti-insulin serum administered.

Experimental studies on the pathogenesis of infections due to Pseudomonas aeruginosa: direct evidence for toxin production during Pseudomonas infection of burned skin tissues.

Direct evidence is presented for the production of an exotoxin by Pseudomonas aeruginosa multiplying at the burned site in an infected mouse. Pseudomonas toxin was assayed by measurement of its ability to catalyze the transfer of radioactivity from [14C]adenine-labeled nicotinamide adenine dinucleotide to elongation factor 2 (adenosine diphosphate ribosylation activity). This enzyme activity was found in saline extracts of burned infected skin but was not present in similar extracts of burned uninfected skin.

The release of alanine by rat diaphragm muscle in vitro.

Alanine release by rat diaphragm muscle in vitro is stimulated by glutamate, valine, leucine and glucose. The stimulation by glutamate and valine (but not leucine) is inhibited by 3-mercaptopicolinate. These results suggest a metabolic route involving phosphoenolpyruvate carboxykinase which directs amino acid carbon skeletons towards pyruvate synthesis for alanine formation.

Granular cell tumors of the central nervous system of rats.

On the basis of our study of 12 cases of granular cell tumors in the brains of rats of different inbred strains, it seems that granular cell tumors are not rate in the central nervous system of untreated, aging BN/Bi rats. In none were metastases found. Awareness of the occurrence of these tumors in the central nervous system of these rats may stimulate further studies into the cellular origin of granular cell tumors that form in the central nervous system of the rat and might help to elucidate the origin of these tumors in general.

Argyrophilic carcinoids in two Syrian hamsters (Mesocricetus auratus).

Argyrophilic carcinoids were found in 2 Syrian hamsters (Mesocricetus auratus). A solitary neoplasm was located in the glandular stomach of a 25.5-month-old animal that had ingested for 12 months laboratory chow to which arecoline and calcium hydroxide [Ca(OH)2] had been added.