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Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 1,225 records · Page 68Linked to original sources
PubMed1988

Determination of deoxyspergualin by gas chromatography-selected-ion monitoring.

A gas chromatographic-selected-ion monitoring method was developed for the sensitive and specific determination of deoxyspergualin in dog plasma using a capillary column and a C8-amide homologue of deoxyspergualin as an internal standard. Extraction and purification of deoxyspergualin from its constituents, 7-guanidinoheptanamide and glyoxylylspermidine, and its possible metabolites was achieved by using CM-Sephadex C-25 column chromatography with stepwise elution with sodium chloride solution. Treatment of deoxyspergualin with acetylacetone resulted in the formation of the volatile pyrimidine derivative of 7-guanidinoheptanamide accompanying hydrolytic cleavage in the alpha-hydroxyglycine moiety of deoxyspergualin. Deoxyspergualin could be determined in a concentration of 10 ng/ml in plasma. The method was applied to the determination of deoxyspergualin in plasma during and after intravenous infusion into dogs.

Animals↗
PubMed1988

The position of the microtubule-organizing center relative to the nucleus is independent of the direction of cell migration in Dictyostelium discoideum.

Dictyostelium amoebae can migrate in several different modes. We tested for correlations of the direction of cell locomotion with the relative positions of the nucleus and microtubule-organizing center (MTOC). Five cases were analyzed on electron micrographs with a microcomputer. Each mode of movement showed characteristic locations of the MTOC relative to the nucleus; however, they differed in the various cases. In randomly migrating interphase amoebae, the number of cells with the MTOC located behind the nucleus was twice as great as those with the MTOC located ahead of the nucleus. During chemotactic migration toward folic acid, cells with the MTOC behind the nucleus were more numerous, with a concomitant reduction of anterior MTOCs. When amoebae aggregated on agar plates, a posterior location of the MTOC was most strikingly favored, whereas in cells aggregating under submerged conditions, the MTOC was indifferently anterior or posterior to the nucleus. (It may be significant that EDTA-resistant cell-cell adhesion was fully expressed in the former cells, but weaker in the latter.) Finally, in the case of chemotactically migrating cells from dissociated pseudoplasmodia, which adhere by means of other molecules, the MTOC was consistently ahead of the nucleus. Thus the MTOC shows no necessary preferential position anterior or posterior to the nucleus; its position, rather, correlates with the type of migration and perhaps with the nature of cell-cell adhesion.

Cell Movement↗
PubMed1988

[Cytomegalic inclusion disease of the salivary glands in sudden infant death syndrome].

The parotid gland and/or the submandibular gland in SIDS cases (180 from Berlin und 75 cases from Hamburg) were examined by means of HE staining, immunohistochemical analysis, in situ hybridization and electron microscopy. The SIDS cases were taken from the last 10 years; the age of the children ranged from 2 weeks to 1 year. Typical cytomegaly inclusion bodies were recognized in 10% (18 cases from Berlin; more girls than boys) and 7% (6 cases from Hamburg; more boys than girls). Our files indicate that the frequency of CMV infection was not age-dependent within the first 12 months of life. Using immunohistochemical analysis and in situ hybridization, virus substances were detected in cytomegal cells as well as in morphologically uninfected cells. The literature on the clinical and epidemiological aspects of cytomegaly indicates that a localized CMV infection of the salivary glands does not sufficiently explain the sudden death of these infants; however, it should be emphasized that cytomegaly can influence the immunological status of the organism.

Cytomegalovirus↗
PubMed1988

Experimental studies on the mechanism of ethanol formation in corpses.

Various in vitro experiments were performed for the purpose of clarifying the mechanism of ethanol production in corpses. Whereas a negligible quantity of ethanol was produced in the blood alone, which was left at room temperature, the quantity of ethanol was slightly increased by addition of glucose to the blood. When saprogens were further added, the quantity was markedly increased. Various materials were added to blood-liver homogenates as specimens, and the mixtures were stored in an incubator at 37 degrees C. As a result of the addition of an antibiotic to the mixture every day, there was hardly any production of ethanol. When alcohol dehydrogenase (ADH) and reduced nicotinamide adenine dinucleotide (NADH) were added, ethanol production was slightly increased. When acetaldehyde was added first, ethanol production was inhibited the next day, but on and after day 2, the quantity of ethanol was more than that in the control material. When pyruvic acid was added first, the results were similar to the above. Pyrazole, cyanamide, and disulfiram completely inhibited the production of ethanol. Ethanol production in corpses is believed to take place through a pathway opposite to that of ethanol metabolism in the living body, under the influence of ADH, ALDH, etc., in saprogens using carbohydrates as substrates.

Acetaldehyde↗
PubMed1988

Close relationships between the cells of the immune system and the epithelial cells in the rat small intestine.

A possible contribution of the intestinal epithelium to the immune defense system was studied by electron microscopy in the rat small intestine. The cells of the immune system (CIS) such as lymphocytes, eosinophils and macrophages penetrate the basal lamina into the epithelium and make close relationships with the absorptive cells. At the points of close apposition, the two cell membranes run parallel at a regular distance of about 20 nm. On the other hand, about 5% of the intestinal absorptive cells also penetrate the basal lamina into the lamina propria via their basal protrusions and show a similar close association with CIS. The basal protrusions contain many microfilaments; this indicates that they are structures with a definite function rather than a simple hernia. These findings are discussed with respect to the transport of antigenic molecules and of intercellular communication between CIS and the intestinal epithelium.

Animals↗
PubMed1988

The locus controlling liver GM1(NeuGc) expression is mapped 1 cM centromeric to H-2K.

The polymorphic variation of liver GM1 (NeuGc) ganglioside was found in inbred strains of the mouse. The genetic analysis using C57BL/10 (GM1-negative) and SWR (GM1-positive) mice revealed that a single autosomal gene (Ggm-1) was involved in the expression of liver GM1(NeuGc) and that C57BL/10 mice lacking GM1(NeuGc) expression carried a defective gene on Ggm-1. Since our previous study on H-2 congenic mice indicated that Ggm-1 was linked to the H-2 complex, in this study we measured recombination frequencies among Ggm-1, Glo-1 and H-2K in the backcross progeny between (C57BL/10 X SWR)F1 and C57BL/10. Ggm-1 was mapped 1 cM centromeric to H-2K on chromosome 17.

Animals↗
PubMed1988

Localization of antigen defined by anti-scirrhous gastric carcinoma monoclonal antibody S202 in fixed human cancer tissues.

Monoclonal antibody S202 reactive with scirrhous gastric carcinoma cell line MK-01 was used in an immunoperoxidase assay to characterize the antigenic profile of a variety of fixed samples. Representative sections of malignant tissue from the stomach, colon, esophagus, pancreas, bile duct, gallbladder and breast were examined by the avidin-biotin complex immunoperoxidase technique and compared. The antibody reacted with 90 out of 98 stomach adenocarcinomas, and with 30 out of 32 colon adenocarcinomas with diffuse cytoplasmic staining, whereas it reacted with only 19 out of 37 breast carcinomas, and 5 out of 10 esophageal squamous cell carcinomas. The antigenic determinants appeared to be a carbohydrate, since it was highly sensitive to sodium periodate.

Adenocarcinoma↗
PubMed1988

In vivo generation of lymphokine-activated killer cells by sensitization with interleukin 2-producing syngeneic T-lymphoma cells.

Culture of C57BL/6 mouse spleen cells with syngeneic EL4 lymphoma cells resulted in no induction of killer cells reactive against EL4 cells. However, in vitro sensitization of C57BL/6 mouse spleen cells with interleukin 2 (IL-2)-producing EL4 lymphoma cells caused the generation of lymphokine-activated killer (LAK) cells, which lyse a variety of tumor cells. Consistent with an in vitro system, we demonstrate that Thy 1.2+, Ly2+, asialo GM1+ LAK cells were successfully induced by in vivo immunization with syngeneic IL-2-producing EL4 lymphoma cells.

Animals↗
PubMed1988

The hypocholesterolemic action of the undigested fraction of soybean protein in rats.

Soybean protein was exhaustively digested with endo- and exo-type microbial proteases and the effect of the digestible low molecular fraction (LMF) and the undigested high molecular fraction (HMF) on the serum cholesterol level was compared to that of the intact protein in rats given a cholesterol-enriched diet. The HMF, peptides relatively abundant in hydrophobic amino acids, was found to be substantially hypocholesterolemic when fed at the nitrogen level equivalent to that of the 20% soybean protein diet, and not only serum but also liver cholesterol levels were similar to those usually encountered in rats given diets free of cholesterol. There was a dose-dependent reduction of serum and liver cholesterol when casein was replaced stepwise with HMF. The cholesterol-lowering action could be attributable to an increased fecal steroid excretion.

Animals↗
PubMed1988

The effect of dietary restriction on mouse T cell functions.

Forty percent dietary restriction on 9-weeks-old C3H/He mice caused decrease of the weight of central lymphoid organs in parallel with the reduction of body weight. However, the percentage of splenic T cells was dramatically increased in diet-restricted mouse spleen cells. Generally, normal mouse spleen cells contained about 30% of Thy 1.2+ T cells, but the restricted mouse spleen cells contained 80% Thy 1.2+ T cells. Ly 1+, L3T4+ T cells, but not Ly 2+ T cells, also increased in diet-restricted mouse compared with the unrestricted mice. In parallel with the dramatic changes of splenic T cells, spleen cells obtained from diet-restricted mice showed higher immunological responses against alloantigen and interleukin 2. It was also demonstrated than nylon-passed splenic T cells obtained from diet-restricted mice showed higher levels of T cell responses against r-IL-2 and alloantigen, indicating that dietary restriction modulates T cell functions themselves.

Animals↗
PubMed1988

Further evidence for the correlation between the primary structure and the stain exclusion banding pattern of the segment-long-spacing crystallites of collagen.

Recently, we have noted the direct correlation between the primary structure of type I collagen and the electron microscopical banding pattern of the negatively stained segment-long-spacing (SLS) crystallites (K. Kobayashi, T. Ito, and T. Hoshino (1986), J. Electr. Microsc. 35, 272-275). In this paper, we examined the correlation in the other types of collagen. Unstained light bands (stain excluding bands) of the negatively stained SLSs of type II and type III collagens were located at the clusters of large hydrophobic amino acid residues along the respective molecules. Photographic averaging of the pattern improved the visual comparison of the correlation. We also noted a few occasions of discrepancy from the above-mentioned correlation. Preliminary computer simulation experiments revealed that, among amino acid parameters so far reported, only the hydrophobicity values of G. D. Rose and S. Roy (1980, Proc. Natl. Acad. Sci. USA 77, 4643-4647) explained the ability of amino acids for the negative staining (stain exclusion) of the collagen SLSs.

Amino Acids↗
PubMed1988

Retinobenzoic acids. 1. Structure-activity relationships of aromatic amides with retinoidal activity.

Two types of aromatic amides, terephthalic monoanilides and (arylcarboxamido)benzoic acids, have been shown to possess potent retinoidal activities and can be classified as retinoids. The structure-activity relationships of these amides are discussed on the basis of differentiation-inducing activity on human promyelocytic leukemia cells HL-60. In generic formula 4 (X = NHCO or CONH), the necessary factors to elicit the retinoidal activities are a medium-sized alkyl group (isopropyl, tert-butyl, etc.) at the meta position and a carboxyl group at the para position of the other benzene ring. The bonding of the amide structure can be reversed, this moiety apparently having the role of locating the two benzene rings at suitable positions with respect to each other. Substitution at the ring position ortho to the amide group or N-methylation of the amide group caused loss of activity, presumably owing to the resultant change of conformation. It is clear that the mutual orientation of the benzylic methyl group(s) and the carboxyl group and their distance apart are essential factors determining the retinoidal activity. Among the synthesized compounds, 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carbamoyl]benz oic acid (Am80) and 4-[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carboxamido] benzoic acid (Am580) were several times more active than retinoic acid in the assay. They are structurally related to retinoic acid, as is clear from the biological activity of the hybrid compounds (M2 and R2).

Amides↗
PubMed1988

Regulatory interactions of calmodulin-binding proteins: phosphorylation of calcineurin by autophosphorylated Ca2+/calmodulin-dependent protein kinase II.

The Ca2+/calmodulin (CaM)-dependent protein phosphatase calcineurin is rapidly phosphorylated (0.8 mol of 32PO4 per mol of 60-kDa subunit of calcineurin) by brain Ca2+/CaM-dependent protein kinase II (CaM-kinase II). This reaction requires the autophosphorylated, Ca2+-independent form of CaM-kinase II since Ca2+/CaM binding to calcineurin inhibits phosphorylation. However, the phosphorylation reaction does require Ca2+, presumably acting through the 19-kDa subunit of calcineurin. Calcineurin is a good substrate for CaM-kinase II, with a Km of 19 microM and Vmax of 2.4 mumol/min per mg. Phosphorylation of calcineurin changed its phosphatase activity with either a 2-fold increase in Km (32P-labeled myosin light chain as substrate) or a 50% decrease in Vmax (p-nitrophenyl phosphate as substrate). The phosphorylated calcineurin exhibited very slow autodephosphorylation (0.09 nmol/min per mg) but was effectively dephosphorylated by brain protein phosphatase IIA. Dephosphorylation, like phosphorylation, was blocked by high concentrations of Ca2+/CaM and stimulated by Ca2+ alone. Thus calcineurin has a regulatory phosphorylation site that is phosphorylated by the Ca2+-independent form of CaM-kinase II and blocked by high concentrations of Ca2+/CaM.

Animals↗
PubMed1988

Hepatic cytochrome P-450 isozyme(s) induced by dietary carcinogenic aromatic amines preferentially in female mice of DBA/2 and other strains.

DBA/2, BALB/c or (BALB/c X DBA/2)F1 (CDF1) mice of both sexes were treated for 1 week with a dietary hepatocarcinogenic tryptophan pyrolysate component (Trp P-1 or Trp P-2), and the activity of hepatic microsomal enzyme(s) for mutagenic activations of Trp P-1 and Trp P-2 were assessed by means of a mutation test with Salmonella typhimurium TA98. In both Ah-responsive (BALB/c and CDF1) and Ah-nonresponsive (DBA/2) mice, the dietary treatment with Trp P-1 or Trp P-2 resulted in a significant increase of the enzyme activity for mutagenic activations of Trp P-1 and Trp P-2 in females but not in males, except the case of male BALB/c mice treated with dietary Trp P-1. Also induction of enzyme(s) in female mice was suppressed by an administration of testosterone. The induced hepatic microsomal enzyme(s) was demonstrated to be cytochrome P-450 isozyme(s) (mol. wt of 55,000 daltons) by immunoblots with use of an anti-rat cytochrome P-448 monoclonal antibody and by selective inhibition of the activity by addition of 7,8-benzoflavone into the mutation assay system. These findings indicate that carcinogenic aromatic amines such as Trp P-1 and Trp P-2 are able to induce hepatic cytochrome P-450 isozyme(s) not only in Ah-responsive mice (BALB/c and CDF1) but also in Ah-nonresponsive DBA/2 mice and that the cytochrome P-450 induction is controlled by androgen(s).

Animals↗
PubMed1988

Genetic polymorphism of ganglioside expression in mouse organs.

In previous studies it was demonstrated that there are three variations as to the expression of liver gangliosides in inbred strains of mice; the first group expresses GM3(NeuGc) as a major component, the second group, GM2(NeuGc), and the third group, GM2(NeuGc), GM1 (NeuGc), and GD1a(NeuGc). In the present study, we attempted to determine which organs, if any, exhibit the same polymorphic variations as those observed in the liver. Thus, the gangliosides in spleen, thymus, heart, lung, kidney, testis, and erythrocytes, as well as those in liver, were examined using a TLC-mapping technique or by one-dimensional TLC. WHT/Ht, BALB/c, and ICR mice, which are typical strains as to the polymorphic expression of liver gangliosides, were used for the analysis. The presence of GM1 was confirmed by not only chemical detection on TLC plates but also with a TLC-immunostaining procedure using choleragenoid. These comparative studies indicated that only erythrocytes exhibited the same polymorphic variations of ganglioside expression as those in the liver, but the other six organs showed specific patterns which were not polymorphic. In addition to this, there were the following two interesting findings. Firstly, WHT/Ht mice, in which GM2(NeuGc) and GM1(NeuGc) are not expressed in the liver and erythrocytes, did not express a detectable amount of GM2(NeuGc) but expressed GM1(NeuGc) in all the other organs. Secondly, marked polymorphic variation was found in the expression of GM4(NeuAc) in the erythrocytes.

Animals↗
PubMed1988

Age-dependent changes in GM1 and GD1a expression in mouse liver.

The ganglioside composition in the liver of SWR/J, A/J, and C57BL/10 (B10) mice was quantitatively analyzed at the ages of 2, 4, 6, 8, and 16 or 20 weeks by TLC-densitometric scanning. In all the strains, GM2, GM1, and GD1a were expressed at the age of 2 weeks. The contents of GM1 and GD1a in SWR/J, A/J, and B10 were 30, 10, and 1% at 4 weeks, and had decreased to 20, 5, and 0%, respectively, at 8 weeks. These results indicate that age-dependent changes in GM1 and GD1a expression occur in mouse liver, and that these three strains show different phenotypes as to this age-dependent expression.

Aging↗