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Biomedical subjects

S Hidaka

Publications and source records attributed to S Hidaka.

175 records · Page 10Linked to original sources

Intrauterine candida infection in premature baby.

An autopsy case of pulmonary candidiasis occurring in an neonatal girl was reported. The mycological examination of the lung take at autopsy revealed only Candida albicans and followed by the elucidation under the microscopic sections prepared with special stains; periodic acid-Schiff and methenamine silver, in the lung, stomach, umbilical cord, and amnion. The presence of candida vaginitis in her mother supported the concept that Candida albicans was the etiological agent of the pulmonary candidiasis.

Adult↗

Mutants of Escherichia coli which block head formation of lambda.

Five mutants of Escherichia coli K12 (lam 24, lam 25, lam 26, lam 27 and lam 646) that block head formation of lambda are described. In vitro complementation tests and electron microscopy demonstrated that in these bacteria phage tails were produced normally, whereas head formation was abnormal, aberrant head-related structures being produced. In lysates prepared from lam 24, lam 25 and lam 26, monsters and empty heads without tail were the predominant structures, whereas in lysates from lam 27 and lam 646, petit lambda and empty heads were the most common structures. The five lam mutations were located in two regions on the bacterial chromosome; lam 24, lam 25 and lam 26 were near the dnaB gene and lam 27 and lam 27 and lam 646 near the lac gene. It was suggested that the former three mutants are new isolates that belong to GroE mutants, whereas the latter two comprise a new group of mutants. Analyses of phage mutants (ov mutants) that overcome the interference by the lam 646 mutation revealed that this mutation blocks normal expression of the gene E of lambda.

Chromosome Mapping↗

Isolation and properties of Escherichia coli mutants which are nonpermissive for the growth of phage lambda.

By selecting survivors of lambda phage infection, mutants of Escherichia coli K12 that block reproduction cycle of the phage have been isolated. Fourteen of these phage-tolerant mutants (lam mutants) were chosen and characterized biochemically and genetically. It was shown that these mutants were tolerant to infection by all the lambdoid phages, except for few cases, but they were susceptible to infection by a non-lambdoid temperate phage (phi299), P1 or T phages. The mutants can be divided into at least three groups: (1) A mutant (lam 16) strain that seems to block normal penetration of phage DNA: (2) Three mutant (lam 64, lam 67 and lam 71) strains that block an "early" step(s) of phage growth, including phage DNA synthesis: (3) Six mutant (lam 24, lam 25, lam 26, lam 27, lam 646 and lam 6) strains that block normal functioning of the gene E products and produce unusual head structures. Some lambdoid phages and lambda mutants that overcome the interference by the lam mutations have been obtained, and were used as tools for characterizing the host mutations. Two (lam 12 and lam 13) mutant strains and one (lam 1) mutant were inferred as affecting the expression of "late" genes, and early gene, respectively, by this test.

Coliphages↗

Comparative effects of diethyldithiocarbamate and N-benzyl-D-glucamine dithiocarbamate on cis-diamminedichloroplatinum-induced toxicity in kidney and gastrointestinal tract in rats.

Sodium diethyldithiocarbamate (DDTC) and sodium N-benzyl-D-glucamine dithiocarbamate (BGD) were compared for their protective effects against cis-diamminedichloroplatinum (DDP)-induced toxicity in kidney and gastrointestinal tract in rats. Rats were injected i.p. with the dithiocarbamates (2.0 mmol kg-1) immediately or 1 h after i.v. injection of DDP (20 mumol kg1). Treatment with BGD immediately or at 1 h after DDP injection effectively prevented the nephrotoxicity of DDP, but administration of DDTC immediately or 1 h after DDP afforded little protection. N-Benzyl-D-glucamine dithiocarbamte significantly reversed the reduction in maltase, sucrase and aminopeptidase activities of jejunal mucosa of rats treated with DDP, whereas treatment with DDTC concurrent with DDP could not reverse the reduction in disaccharidase activity following DDP injection. The platinum concentrations in liver and kidney were significantly decreased by treatment with BGD and DDTC. The treatment with DDTC at 1 h after DDP was more effective on the reduction of platinum concentrations in these tissues than that immediately after DDP. There was no difference between the renal and hepatic concentrations of platinum in two time intervals of BGD. The pharmacokinetic studies indicated that DDTC is more rapidly metabolized than BGD, resulting in larger total clearance and elimination rate constant values. These results reveal that the administration of BGD immediately and at 1 h after DDP can protect against the renal and gastrointestinal toxicities caused by DDP, whereas DDTC afforded little protection, and that the time interval between administration of DDP and DDTC greatly influences its protective effect on DDP-induced toxicity, indicating that the chelation therapy of BGD for DDP is superior to that of DDTC.

Animals↗

The network properties of bipolar-bipolar cell coupling in the retina of teleost fishes.

Retinal bipolar cells exhibit a center-surround antagonistic receptive field to a light stimulus (Werblin & Dowling, 1969; Kaneko, 1970), and thus constitute an early stage of spatial information processing. We injected Lucifer Yellow and a small biotinylated tracer, biocytin, into bipolar cells of the teleost retina to examine electrical coupling in these cells. Lucifer-Yellow coupling was observed in one of 55 stained bipolar cells; the coupling pattern was one injected bipolar cell and three surrounding cells. Biocytin coupling was observed in 16 of 55 stained bipolar cells, six of which were ON center and ten OFF center. Although biocytin usually coupled to three to six bipolar cells, some OFF-center bipolar cells showed strong coupling to more than 20 cells. The biocytin-coupled bipolar cells were morphologically homologous. Membrane appositions resembling gap junctions were found between dendrites and between axon terminals of neighboring bipolar cells. In the strongest biocytin-coupled bipolar cells, the contacts between bipolar cells and cone photoreceptor cells were examined after reconstruction of the dendritic trees of five well-stained, serially sectioned OFF-center bipolar cells. Each of these bipolar cells was in contact with different numbers of cones: 11 to 20 for twin cones and two to four for single cones. This implies that, although these bipolar cells belong to the same category, the signal inputs differ among bipolar cells. Numerical simulation conducted on a hexagonal array network model demonstrated that the electrical coupling of bipolar cells can decrease the difference in input (approximately 80%) without causing significant loss of spatial resolution. Our results suggest that electrical coupling of bipolar cells has the advantage of decreasing the dispersion of input signals from cones, and permits bipolar cells of the same class to respond to light with similar properties.

Animals↗

Effect of different experimental conditions on lipogenesis and substrate oxidation in isolated adipocytes from fattening Holstein steers.

The present study was undertaken to provide further information on lipogenesis in isolated adipocytes from the subcutaneous adipose tissue of fattening steers. The main aims were to compare different incubation media and to clarify the effects of fetal bovine serum (FBS) on lipogenesis and substrate oxidation rate in the adipocytes. The isolated adipocytes were prepared by the collagenase digestion technique. The changes in cellularity, the incorporation rates of acetate or glucose into lipid molecules, and the oxidation rates to CO2 both in fresh and preincubated adipocytes were measured in different media. It was shown that FBS increased significantly both lipogenesis and the oxidation rates of glucose or acetate in the fresh adipocytes but insulin did not. In isolated adipocytes preincubated for 24 and 48 h, the cellularity, the incorporation rate of glucose into lipid molecules, and the oxidation rates of glucose or acetate to CO2 were not different to those in fresh adipocytes, but the incorporation rate of acetate into lipid molecules was significantly lower.

Acetates↗

Production and properties of hemagglutinin of Haemophilus gallinarum.

Production of hemagglutinin (HA) of Haemophilus gallinarum was compared in some media, and its properties were studied. HA was produced in Kato's media, brain heart infusion (BHI) broth containing beta-diphosphopyridine nucleotide, and chicken meat infusion (CMI) broth. The HA in CMI broth different according to the concentration of the chicken serum; no HA titer was found in 0.5% or more chicken serum, but HA was activated by storage in a refrigerator. Cells of H. gallinarum cultured for a long time had markedly decreased HA titer. A weak HA was produced in blood and Kato's agars, but no titer appeared in CMI and BHI agars. HA of H. gallinarum was heat-labile and inactivated by formalin, ethanol, methanol, and ethyl acetate. On the other hand, HA was resistant to chloroform, acetone, and some enzymes. Moreover, the HA titer of cell cultured in CMI broth was enhanced by hyaluronidase. H. gallinarum in Kato's and BHI broths were pleomorphic rods with or without a capsule, but were capsulated ovoid cells in CMI broth, according to electron microscopy.

Agglutinins↗