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Biomedical subjects

T Tamura

Publications and source records attributed to T Tamura.

At least 37 records · Page 2Linked to original sources

Absorption of mono- and polyglutamyl folates in zinc-depleted man.

The effect of experimental zinc depletion on the intestinal absorption of mono- and polyglutamyl folates was assessed in six healthy male subjects by measuring the increase in serum folate after an oral dose of pteroylmonoglutamate and pteroylheptaglutamate before and after initiation of a zinc-deficient diet. At the beginning of the study, no differences were detected in the absorption of pteroylmono- and heptaglutamate. After zinc depletion, the rise in serum folate after an oral dose of pteroylheptaglutamate was reduced by an average of 53% while pteroylmonoglutamate absorption appeared to be unchanged. These data suggest that zinc depletion results in a decreased intestinal hydrolysis of pteroylpolyglutamate and that intestinal conjugase in man is a zinc-dependent enzyme.

Adult

Modification of immune response in nude mice infected with mouse hepatitis virus.

In nude mice experimentally infected with mouse hepatitis virus (MHV), the numbers of early and later plaque forming cells (PFC) to sheep red blood cells (SRBC) generated in the spleen were 7 to 20 times and 2 to 163 times, respectively, greater than those in non-infected nude mice, when SRBC were given at day 0 to day 21 postinfection. Splenic theta-positive lymphocytes in infected nude mice were shown to increase only at day 10 or more postinfection. PFC response to bacterial lipopolysaccharide, a T cell-independent antigen, was not modified in MHV-infected nude mice.

Animals

Availability of monoglutamyl and polyglutamyl folates in normal subjects and in patients with coeliac sprue.

Intestinal folate absorption was assessed in six normal subjects and in four patients with coeliac sprue who were studied before and after treatment by dietary gluten exclusion. Comparisons were made of the luminal disappearance from the perfused jejunum of 3H-pteroylmonoglutamate and pteroyl 14C-glutamylhexaglutamate, and of the 48-hour urinary recovery of each isotope after perfusion and a tissue saturating dose of folic acid. The labelled urinary folates consisted of folic acid, 10-formyltetrahydrofolate, and 5-methyltetrahydrofolate. In each group urinary recovery of 3H was significantly greater than that of 14C, confirming the evidence from jejunal perfusion that the availability of monoglutamyl folate is greater than that of polyglutamyl folate. According to the urinary recovery data, both folates were poorly absorbed in untreated coeliac sprue, but were normally absorbed after treatment. Assuming uniform displacement of the absorbed labelled folates by the parenteral flushing dose, the finding of greater urinary isotope recovery than of luminal folate disappearance from the perfused proximal jejunal segment suggests an adaptation of the distal small bowel for folate absorption in coeliac sprue.

Adult

Isolation of mouse hepatitis virus from infant mice with fatal diarrhea.

An epizootic of fatal diarrhea occurred in mice which were approximately 10 days of age. The enteric lesions were similar to those reported in lethal intestinal virus of infant mice, but many diseased mice also had necrotic hepatitis. Mouse hepatitis virus antigen was demonstrated in the affected intestine and liver, and a virus that produced syncitium formation in mouse brain tumor cell culture was isolated from the intestines, livers, and brains. The virus was capable of producing intestinal and hepatic lesions similar to the naturally occurring disease after inoculation into suckling mice. Electron microscopy revealed viral particles within affected intestinal epithelial cells of the inoculated mice.

Animals

Occurrence of lanosterol and lanostenol in seeds of red pepper (Capsicum annuum).

Cycloartenol and cycloartanol are the major components of the 4,4-dimethylsterol fraction separated from the seeds of red pepper (Capsicum annuum, Solanaceae). Lanosterol and lanostenol, whose occurrence in higher plants has hitherto been known as extremely rare, are identified in the fraction by gas liquid chromatography, combined gas liquid chromatography-mass spectrometry, and isolation as their epoxides.

Chromatography, Gas