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Biomedical subjects

C Hayashi

Publications and source records attributed to C Hayashi.

At least 37 records · Page 2Linked to original sources
PubMed1997

[A study of the association between the aortic pulse wave velocity and atherosclerotic risk factors among Japanese Americans in Seattle, U.S.A].

Cardiovascular disease prevention screening was conducted among 1389 Japanese Americans in Seattle, Washington, U.S.A. from 1989 to 1994. The association between atherosclerotic risk factors and the aortic pulse wave velocity (PWV), an indicator of atherosclerosis, was examined by using multiple logistic regression method. Based on a study in 1996 by Suzuki et al. on the association between PWV and atherosclerotic indicators, abnormally high PWV was defined as 8.0 m/sec. and over for those less than 60 years of age and 9.0 m/sec. and over for those 60 years of age and older Significant odds ratios to estimate the risk for the presence of abnormally high PWV were found in age >or= 60 years (4.31, p < 0.001), hypertension (2.00, p < 0.001), diabetes (5.65, p < 0.001), current drinker (0.44, p < 0.001), ex-drinker (0.49, p < 0.05), and ex-smoker (1.82, p < 0.01) among men. Women showed a similar association: age > or = 60 years (3.03, p < 0.001), hypertension (1.94, p < 0.01), diabetes (2.47, p < 0.05), TC/HDL-C >or= 4.5 (1.98, p < 0.001), current drinker (0.47, p < 0.001), and ex-drinker (0.45, p < 0.05). Our findings are almost identical to those from other studies showing the association between coronary heart disease and its risk factors. The question of whether PWV can be a predictor of atherosclerotic diseases, particularly coronary heart disease, remains to be answered by additional studies. However, PWV may serve as a simple and valuable indicator to estimate the extent and severity of asymptomatic atherosclerosis in the large artery.

Alcohol Drinking↗
PubMed1996

Singlet oxygen (1 delta g) generation from coproporphyrin in Propionibacterium acnes on irradiation.

Although singlet oxygen has been postulated to be a highly reactive and toxic intermediate, there has been no evidence of considerable generation of singlet oxygen in vivo level except for special cases. In this work, we firstly measured the near-infrared emission spectra corresponding to the O2(1 delta g) --> O2(3 epsilon g-) transition of singlet oxygen of cutaneous Propionibacterium acnes (P. acnes) porphyrin under laser excitation. A comparison of the singlet oxygen production of coproporphyrin, which is produced predominantly from P. acnes, with that of other photosensitizers revealed coproporphyrin to be a highly efficient singlet oxygen generator under ultraviolet light A irradiation on the skin. These results suggest that singlet oxygen can be generated on the skin surface from P. acnes porphyrin under ultraviolet irradiation and induce serious damage to the skin.

Coproporphyrins↗
PubMed1996

Evidence from milk casein genes that cetaceans are close relatives of hippopotamid artiodactyls.

The inferred transition from terrestrial hoofed mammal to fully aquatic cetacean has been intensively studied with fossil evidence. However, large sections of this remarkable evolutionary sequence are missing. Phylogenetic analysis of extant taxa may help to fill in some of these gaps. In this report, kappa-casein (exon 4) and beta-casein (exon 7) milk protein genes from cetaceans and other placental mammals were PCR-amplified, sequenced, and aligned to previously published sequences. Phylogenetic analyses of the casein data suggest that hippopotamid artiodactyls are more closely related to cetaceans than to other artiodactyls (even-toed hoofed mammals). An analysis of the nuclear casein sequences combined with published mitochondrial cytochrome b DNA sequences also supports the Cetacea/Hippopotamidae sister group. This affinity implies that some of the aquatic traits of cetaceans were derived in the common ancestor of Cetacea and Hippopotamidae. An extant "missing link" to Cetacea may have been overlooked by science since the description of the semiaquatic Hippopotamus in 1758. Paleontological information is grossly inconsistent with this hypothesis. If the casein phylogeny is accurate, large gaps in the fossil record as well as extensive morphological reversals and convergences must be acknowledged.

Amino Acid Sequence↗
PubMed1996

Effects of head cooling on sweat rate in exercising subjects wearing protective clothing and mask for pesticide.

This study examined the effects of the head cooling on the sweat rates in 6 healthy female subjects at an ambient temperature of 28 degrees C and a relative humidity of 60%. The exercising subjects wore protective clothing and a mask for pesticide. Head cooling was made by putting frozen gel strips on the parietal and the front head which were held by a net-bandage (with cooling). On separate days, the same experiments were made without head cooling (without cooling). The total weight of the frozen gel strips was 250 g. After the subjects rested for 15 min in a chair, they repeated three times the work/rest schedule of 15 min exercise on a bicycle ergometer (50 W) followed by 5 min rest. Frozen gel strips were put on the head just before the first exercise bout. Main results were summarized as follows: 1) The forearm sweat rate, heart rate and the changes in Tre from the initial level (delta Tre) were significantly lower "with cooling" than "without cooling". 2) The amount of sweat adhered to the clothing ensemble was significantly lower "with cooling" than "without cooling". 3) The changes in Tty from the initial level (delta Tty) tended to be clearly lower "with cooling" than "without cooling". 4) Skin temperatures of the forehead and the cheek under a mask tended to be lower "with cooling" than "without cooling". 5) Subjective sensation ratings seemed to be improved in most subjects "with cooling". Thus, it was concluded that head cooling seemed to be more effective in reducing thermal strain in working subjects wearing the protective clothing and a mask for pesticide at hot environments.

Adult↗
PubMed1996

Cholesterol levels among Japanese Americans and other populations: Seattle Nikkei Health Study.

The purpose of this study was to compare average cholesterol levels between Seattle based Japanese Americans and three other populations: U.S. population, native Japanese population and native Japanese urban workers. A total of 1,466 Japanese Americans (724 men and 742 women) participated in cardiovascular disease screening in the Seattle area during 1989 94. Data sources for comparisons are from the Third National Health and Nutrition Examination Survey for 1988-91, the results of the National Cardiovascular Disease Examination Survey in Japan for 1990, and cardiovascular disease screening conducted by the Epidemiological Arteriosclerosis Research Institute in Japan for 1989. Total cholesterol and triglyceride levels of Seattle Japanese American men and women were highest among the four populations. Among men, high density lipoprotein cholesterol (HDL-C) levels for Seattle Japanese Americans and native Japanese were similar and fell between those of urban Japanese workers and the U.S. population. In women, the average HDL C levels were highest in the Japanese urban workers, second highest in Seattle Japanese Americans, and lowest in both the U.S. population and native Japanese population. These differences in lipid levels may be caused by both genetic and environmental factors, which are now under investigation.

Adult↗
PubMed1996

Heliquinomycin, a new inhibitor of DNA helicase, produced by Streptomyces sp. MJ929-SF2 I. Taxonomy, production, isolation, physico-chemical properties and biological activities.

Heliquinomycin was isolated as a part of a program designed to find inhibitors of DNA helicase from microbial sources. It was purified from the culture broth of Streptomyces sp. MJ929-SF2 by solvent extraction and serial chromatographies of centrifugal partition chromatography, Sephadex LH-20 and Capcell Pak C18 (HPLC). The isolated red powder was analyzed to have the molecular formula of C33H30O17. It inhibited partially purified DNA helicase from HeLa cell in a non-competitive manner with the inhibition constant (Ki) of 6.8 mM. Heliquinomycin exhibited biological activity against microorganisms including MRSA, and cultured cell lines.

Animals↗
PubMed1995

Multi-enzyme reference material from established human cell lines and human sources.

A multi-enzyme reference material was prepared from seven enzymes of asparatate aminotransferase (AST, EC 2.6.1.1), alanine aminotransferase (ALT, EC 2.6.1.2), alkaline phosphatase (ALP, EC 3.1.3.1), lactate dehydrogenase (LD, EC 1.1.1.27), creatine kinase (CK, EC 2.7.2.2), gamma-glutamyltranspeptidase (gamma-GT, EC 2.3.2.2) and amylase (AMY, EC 3.2.1.1) which were purified from human sources including established human cell lines. The enzymatic properties of the material closely resembled those of human serum. In lyophilized form the preparation was stable for at least 200 days when stored at 40 degrees C. Intermethod comparisons of the enzyme activities in 80 clinical specimens were done by correcting the mean values with calibration constants for different assay methods resulting from use of a human serum, the multi-enzyme reference and a commercial control serum. The results from the comparison for the six enzymes of AST, ALT, LD, CK, gamma-GT and AMY in use of the multi-enzyme reference were almost the same as those with use of a human serum as a calibrator, but were not satisfactory for ALP. Even though further search for more reliable material for ALP is required the multi-enzyme reference material can be used for standardization in clinical chemistry.

Alanine Transaminase↗
PubMed1995

Protein kinase C inhibitor potentiates the agonist-induced GTPase activity in COS cell membranes expressing delta-opioid receptor.

In COS-7 cell membranes expressing cloned delta-opioid receptor, [D-Ser2, Leu5]enkephalin-Thr6, an opioid delta-agonist, showed no significant stimulation of high-affinity GTPase, while this agonist binding showed a guanine nucleotide sensitivity. Significant stimulation of GTPase activity by this agonist was observed only when the cells were pretreated with 0.1 microM calphostin C, a protein kinase C inhibitor, and when this inhibitor was further added to the reaction mixture at 1 microM. These findings suggest that protein kinase C is involved in the heterologous desensitization of delta-opioid receptor in the cells.

Analgesics↗
PubMed1995

Sweat responses to pesticide-proof clothing influenced by textile materials.

Themoregulatory responses were compared at an ambient temperature of 30 degrees C and a relative humidity of 50% between two kinds of protective clothing for pesticide spraying. One was made of nylon with wet coating polyurethane (A) and another was made of cotton with water repellent finish (B). The clothing ensemble was composed of a short-sleeved cotton shirt, long cotton underpants, cotton socks, shoes and the protective clothing. Five young female adults served as subjects. They took a rest with protective clothing ensemble for 15 min and then walked on a motor-driven treadmill (80m/min, 5% uphill grade) for 40 min, followed by 20-min rest. The increase of forearm sweat rate was higher in clothing A than in clothing B in 4 out of 5 subjects, although the average values were not significantly different. The total sweat rate of the whole body was also significantly larger in clothing A. Mean skin temperature and local skin temperatures in the arm, the chest and the thigh were significantly higher in clothing A than in clothing B. Clothing microclimate humidity was significantly higher in clothing A, while clothing microclimate temperature tended to be higher in clothing A. Individual observations about thermal, humidity and comfort sensation disclosed that the sensation was improved as a whole in clothing B. Local sweat rate was linearly related to mean body temperature and the regression line for clothing A was located above that for clothing B in 4 out of 5 subjects.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Protein kinase C involvement in homologous desensitization of delta-opioid receptor coupled to Gi1-phospholipase C activation in Xenopus oocytes.

We have developed the coexpression system of both delta-opioid receptor (DOR1) and M2-muscarinic receptor (M2) which mediate agonist-evoked currents due to common post-receptor mechanisms including Gi1 and phospholipase C (PLC) activation in Xenopus oocytes reconstituted with Gi1 alpha. The DOR1-currents by 100 nM D-Ser2-leu-enkephalin-Thr6 (DSLET) were selectively desensitized by 10 nM phorbol 12-myristate 13-acetate (PMA). The PMA-desensitization of DSLET-currents was abolished in the presence of calphostin C, a protein kinase C inhibitor, or reversed by an intracellular injection of calcineurin, a protein phosphatase 2B. When a higher concentration (3 microM) of DSLET was used, DSLET-currents were rapidly desensitized by repeated challenges of DSLET itself. However, repeated challenges of 10 microM ACh caused no influence on such DSLET- or M2-currents. The desensitization of DSLET-currents was selectively reversed by protein kinase C inhibitors. Similar results were also obtained with various delta-opioid agonists. These results suggest that protein kinase C is involved in the homologous desensitization of delta-opioid receptors.

Animals↗
PubMed1994

Species and age-dependent differences of functional coupling between opioid delta-receptor and G-proteins and possible involvement of protein kinase C in striatal membranes.

[D-Ser2,Leu5]-enkephalin-Thr6 (DSLET) and [D-Pen2,5]-enkephalin (DPDPE), both delta-agonists, stimulated the high affinity GTPase in the rat striatal membranes in a naltrindole-reversible manner. Similar stimulation was also observed in the striatal membrane preparations of 16-week-old guinea pigs, while not in those preparations of 4-week-old ones. When calphostin C, a protein kinase C inhibitor, was added to the reaction mixture, DSLET showed a marked stimulation in this activity in 4-week guinea pig striatal membranes. There was no effect of KT5720, a cyclic AMP-dependent protein kinase inhibitor, on such delta-opioid-mediated responses. These findings suggest that protein kinase C is locally involved in the functional uncoupling of delta-receptors to G-proteins in the striatum of young guinea pigs.

Aging↗
PubMed1994

Alterations of fibroblast metabolism in early ligature-induced periodontitis in the cynomolgus monkey.

Cellular and biochemical observations were made of fibroblasts harvested from ligature-induced periodontitis and treated gingivitis areas in four adult female cynomolgus monkeys (Macaca fascicularis) to define the changes that occur in the early periodontitis lesion. Compared with fibroblasts from the treated sites, fibroblasts from the diseased areas had a significantly higher rate of proliferation, produced about two-thirds the amount of total protein and collagen, and failed to respond to TGF-beta, which normally stimulates extracellular matrix formation in mesenchymal cells. The diseased cells were also deficient in the activity of poly(ADP-ribose) synthetase, an enzyme involved in the repair of DNA breaks such as occur from the insults of superoxide and other active radicals present in inflamed areas. Although the precise nature of these biochemical defects is not fully elucidated, they may have an important bearing on chronic periodontitis cases with a "downhill" course.

Animals↗
PubMed1993

Dephostatin, a novel protein tyrosine phosphatase inhibitor produced by Streptomyces. I. Taxonomy, isolation, and characterization.

A novel inhibitor of protein tyrosine phosphatase, dephostatin, was isolated from the culture broth of a strain of Streptomyces. The active principle was extracted from the broth filtrate with ethyl acetate and purified by silica gel chromatography and by HPLC. Dephostatin inhibited protein tyrosine phosphatase prepared from a human neoplastic T-cell line with an IC50 at 7.7 microM. The inhibitory pattern of dephostatin was competitive against the substrate. Dephostatin inhibited the growth of Jurkat cells.

Cell Division↗
PubMed1992

The binding of nonmuscle caldesmon from brain to microtubules. Regulations by Ca(2+)-calmodulin and cdc2 kinase.

Nonmuscle caldesmon from bovine brain bound to microtubules with a stoichiometry of five tubulin dimers to one molecule of caldesmon with values of Ka 4.5 x 10(5) M-1. The binding of caldesmon to microtubules was inhibited in the presence of Ca2+ and calmodulin. The phosphorylation of caldesmon by cdc2 kinase also eliminated the microtubule-binding activity. These results suggest that caldesmon may play a physiological role in the functions of microtubules.

Animals↗
PubMed1992

Characterization of smooth muscle caldesmon as a microtubule-associated protein.

We have previously shown that nonmuscle caldesmon copurified with brain microtubules binds to microtubules in vitro [Ishikawa et al.: FEBS Lett. 299:54-56, 1992]. To explore the role of caldesmon in the functions of microtubules, further characterization was performed using smooth muscle caldesmon, whose molecular structure and function have been best-characterized in all caldesmon species. Smooth muscle caldesmon bound to microtubules with a stoichiometry of five tubulin dimers to one molecule of caldesmon with the binding constant of 1.1 x 10(6) M-1. The binding of caldesmon to microtubules was inhibited in the presence of Ca2+ and calmodulin. Partial digestion of the caldesmon with alpha-chymotrypsin revealed that the binding site of the caldesmon for microtubules lay in the 34-kDa C-terminal domain. When the caldesmon was in the dimeric form in the absence of a reducing agent, the caldesmon cross-linked microtubules to form bundles. Further, the caldesmon potentiated the polymerization of tubulin, and inhibited the in vitro movement of microtubules on dynein. These results suggest that caldesmon may be involved in the regulation by Ca2+ of the functions of microtubules.

Animals↗
PubMed1992

Detection of interleukin-1 beta in human periapical lesions.

Interleukins are involved in modulating bone cell activity. Interleukin-1 (IL-1) has been shown to be potent stimuli of bone resorption in organ culture. This hormone-peptide is produced primarily by monocytes and macrophages. Diverse inflammatory cell types are clearly present in periapical lesions. The purpose of this study was to detect IL-1 beta activity in human periapical lesions. Eight human periapical lesions were examined for the presence of IL-1 beta. Pulp tissue of clinically impacted teeth were used as controls. Each specimen was quick-frozen and stored in liquid nitrogen. IL-1 beta activity was measured with, an IL-1 beta enzyme-linked immunosorbent assay that used monoclonal antibodies specific for IL-1 beta. Periapical samples exhibited significant activity of IL-1 beta (mean 604.4 +/- 563.0 pg/mg protein), whereas normal pulp had no activity. These results demonstrate that IL-1 beta is produced and released locally in inflammatory periapical lesions to mediate bone resorption.

Adult↗
PubMed1992

Benarthin: a new inhibitor of pyroglutamyl peptidase. I. Taxonomy, fermentation, isolation and biological activities.

We found benarthin, a new inhibitor of pyroglutamyl peptidase, in the fermentation broth of Streptomyces xanthophaeus MJ244-SF1. It was purified by column chromatography and centrifugal partition chromatography (CPC) and then was isolated as a colorless powder. The binding of benarthin was competitive with substrate and its inhibition constant (Ki) was 1.2 x 10(-6) M.

Classification↗