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Biomedical subjects

M Yamamura

Publications and source records attributed to M Yamamura.

At least 325 records · Page 18Linked to original sources
PubMed1978

A new semiquantitative radiometric opsonin assay. Selective measurement of opsonizing capacity of the alternative pathway.

A new semiquantitative radiometric opsonin assay is described. It was found that the opsonin activity generated by incubating brewer's yeast, Saccharomyces cerevisiae, in medium containing less than 5% human serum was exclusively complement dependent. In contrast, C. albicans was effectively opsonized in the absence of complement. Antibodies and the early classical complement pathway did not contribute to the opsonization of S. cerevisiae and neither did C5-9. The brewer's yeast assay can therefore be used for measuring selectively the opsonizing capacity of the alternative pathway. Sera from approximately 7% of apparently healthy adult controls consistently failed to generate significant opsonin activity while 8 out of 26 patients with suspected immune deficiency of unknown cause were defective in this assay. All opsonin deficient sera so far tested had haemolytically normal alternative pathway and Factor B activity.

Adult↗
PubMed1977

Microbody of n-alkane-grown yeast. Enzyme localization in the isolated microbody.

Microbodies appearing abundantly in n-alkane-grown cells of Candida tropicalis pK 233 were isolated by means of sucrose density gradient centrifugation. Electron microscopical observation showed that the microbodies isolated were intact. Localization of catalase and D-amino acid oxidase in the isolated microbodies was confirmed. Isocitrate lyase, melate synthase and NADP-linked isocitrate dehydrogenase were also located in the microbody, but malate dehydrogenase, citrate synthase, aconitase and NAD-linked isocitrate dehydrogenase were not. Neither cytochrome P-450 not NADPH-cytochrome c reductase, the components involved in the n-alkane hydroxylation system of the yeast, were detected in the microbody fraction.

Alkanes↗
PubMed1977

Phagocytosis measured as inhibition of uridine uptake by Candida albicans.

Inhibition of 3H-uridine incorporation into Candida albicans can be used as a sensitive index of phagocytic function because: 1) there is a linear correlation between uridine incorporation and yeast number; 2) phagocytic cells do not incorporate significant amounts of uridine in short term cultures; and 3) C. albicans replicating inside phagocytic cells does not take up uridine from culture medium. Appropriate conditions for measuring phagocytic capacity of human polymorphonuclear cells (PMN's) were 5 x 10(5) C. albicans and 5 x 10(4) PMNs in 0.5 ml of medium containing 2.5% AB serum. This mixture was incubated for 30 min at 37 degrees C. Aliquots were then transferred into microtiter wells and incubated for a further 60 min in the presence of 3H-uridine. Under these conditions PMN leucocytes from 25 healthy individuals caused suppression of uridine incorporation ranging from 33 to 75% (50 +/- 12).

Candida albicans↗
PubMed1977

Participation of C3 in intracellular killing of Candida albicans.

Using new objective methods for measuring, independently, phagcytosis and killing, it was demonstrated that Candida albicans opsonized by C3-deficient serum was ingested by not killed in vitro by human polymorphonuclear leukocytes. Killing could be induced by adding purified C3 to the C3-deficient serum. It is concluded that C3 participates directely in the intracellular process leading to phagocytic killing of C. albicans.

Candida albicans↗
PubMed1977

Production of uricase by Candida tropicalis using n-alkane as a substrate.

Production of uricase (urate oxidase, EC 1.7.3.3) by n-alkane-utilizing Candida tropicalis pK233 was studied. Although the yeast showed very low enzyme productivity under growing conditions on glucose or an n-alkane mixture (C10 to C13) (less than 2 U/g of dry cells), enzyme formation was enhanced markedly in an induction medium consisting of potassium phosphate buffer, MgSO4, uric acid, and an n-alkane mixture (47 U/g of dry cells) or glucose (21 U/g of dry cells). Of the carbon sources tested, the n-alkane mixture was the most suitable for enzyme production. Appropriate aeration also stimulated uricase formation. In addition to uric acid, xanthine, guanine, adenine, and hypoxanthine were also effective for inducing uricase. Under optimum conditions, the maximum yield of the enzyme was 91 U/g of dry cells. Uricase thus induced was localized in the microbodies of the yeast.

Alkanes↗
PubMed1976

Standardisation of the mixed lymphocyte reaction.

The mixed lymphocyte reaction has been optimised with Ficoll--Triosil separated lymphocytes: 100,000 responding cells with 100,000 mitomycin-C-blocked stimulating cells, in 0.2 ml of TC 199 with 10% AB-negative known normal serum in Cook microplates. After incubation at 37 degree C for 120 h, 2 muCi of [3H]thymidine was added, harvesting after a further 15 h at 37 degree C. A pool of stimulating cells, freshly separated from 5 normal subjects (usable up to 36 h if kept at 4 degree C), produced a Gaussian normal range of increment in CPM from 17,000--88,000, with a between-batch coefficient of variation for triplicates of 22%. For tests against stimulating cells from a single donor a transformation index above 1.64 was significant.

Humans↗
PubMed1976

A chromium release assay for phagocytic killing of Candida albicans.

Intracellular killing of Candida albicans was measured by a chromium release technique. Appropriate conditons were equal numbers of polymorphonuclear leucocytes (PMN) and 51Chromium labelled C. albicans (10 6/ml), fresh plasma at a final concentration of 2.5%, incubated at 37degreesC for 60 min. Using normal PMNs, 35-71% of releasable chromium was liberated into the supernatant under these conditions. This assay is easy to perform, requires a small amount of blood and offers and objective measurement of intracellular killing of C. albicans.

Candida albicans↗
PubMed1976

The elective treatment of graft-versus-host disease following a bone marrow graft from a father to a son with severe combined immunodeficiency.

The details of the first successful bone marrow graft from father to son are described. The recipient developed an acute graft-versus-host reaction on the seventh day which was successfully treated with anit-lymphocyte globulin and methotrexate. This regime did not destroy the graft and the child is alive and well with normal immunological function some 2 1/2 years later.

Antilymphocyte Serum↗
PubMed1976

[Pharmacological studies of an antipschotic agent, penfluridol. (1). The central pharmacological actions].

Neuropharmacological properties of penfluridol (TLP-607) were investigated in experimental animals and were compared with those of haloperidol and chlorpromazine. Locomotor activity of mice significantly decreased at doses of 16-32 mg/kg p.o. Like haloperidol and chlorpromazine, TLP-607 (4-16 mg/kg p.o.) demonstrated catalepsy lasting for 48-72 hr in rats. TLP-607 strongly inhibited apomorphine-induced emesis in dogs and the ED50 was 0.016 mg/kg p.o. This effect lasted for 192 hr when administered 0.04 mg/kg p.o. TLP-607 antagnonized methamphetamine-induced stereotyped behavior in rats, and the ED50 was 1.83 ng/kg p.o. TLP-607 also inhibited conditioned avoidance responses in rats, and the ED50's in the pole climbing and Sidman avoidance methods were 6.73 and 3.4 mg/kg p.o., respectively. TLP-607 neither inhibited motor coordination nor enhanced hexobarbital-induced anesthesia in mice. These results suggest that TLP-607 is a potent and long-acting antipsychotic drug which has less neurotoxic side-effects.

Agonistic Behavior↗
PubMed1975

Effects of penfluridol and other drugs on apomorphine-induced stereotyped behavior in monkeys.

The effects of some drugs on apomorphine-induced stereotyped behavior were studied in male cynomolgus monkeys. Apomorphine produced the dose-dependent stereotyped behavior characterized mainly by continuous licking and biting, and repetitive movements of the hands, head and body in the monkeys. Penfluridol as well as haloperidol showed a clear antagonistic effect on the apomorphine-induced stereotyped behavior, while chlorpromazine was less antagonistic than haloperidol. The antagonistic effect of penfluridol lasted longer than that of haloperidol. Reserpine did not inhibit the apomorphine-induced stereotyped behavior though the drug elicited markedly the behavioral depression and alpha-methyl-p-tyrosine also did not block the stereotyped behavior. Nialamide did not depress the apomorphine-induced stereotyped behavior. In provoking the stereotyped behavior in monkeys, apomorphine probably acts directly on dopamine receptors in the extrapyramidal system, and penfluridol is suggested to act as a dopamine receptor blocker with a long action. The results indicate that protection against apomorphine-induced stereotyped behavior in monkeys may be a useful method for evaluating neuroleptic drugs.

Animals↗