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Biomedical subjects

H Shibata

Publications and source records attributed to H Shibata.

At least 289 records · Page 16Linked to original sources
PubMed1996

The health status of elderly people and the new direction of health services.

The projected increase of people in Japan aged 75 years and older in the years to come implies the increase of the disabled elderly. Thus, the core of societal preparation for the aging of the population is generally considered to be the expansion of services for the disabled elderly. However, gerontological studies on the health status of the elderly conducted in Japan show that the prevalence of disability is quite low and even decreasing. Relative to the services for the disabled elderly, preventive services for the healthy elderly have long been overlooked. In 1994, the Metropolitan Tokyo Government organized a task force to develop a new health education program as the preventive health service for the healthy urban elderly. A preliminary plan outlining the health education program--consisting of propagation with a booklet, on-the-job training of practitioners, and development of new curricula and teaching materials--was proposed by the authors for discussion within the task force. Although the inquiry has just begun and the plan is still nascent, it seems adequate to fit the needs for preventive health services in the near future.

Aged↗
PubMed1996

Two distinct signaling pathways activated by activin A in glucose-responsive pancreatic beta-cell lines.

Activin A stimulates insulin secretion in pancreatic beta-cells by a calcium-dependent mechanism. The present study was conducted to further characterize the effects of activin A in two glucose-responsive insulinoma cell lines, MIN6 and HIT-T15 cells. In HIT-T15 cells, activin A evoked an increase in cytoplasmic free calcium concentration, stimulated insulin secretion, maintained glucose responsiveness of the cells and inhibited DNA synthesis. However, activin A did not have any effect in MIN6 cells. Measurement of 125I-labeled activin A binding in MIN6 cells revealed that the number of binding sites was markedly reduced, suggesting that the refractoriness was due, at least partly, to the reduced numbers of the activin receptor. Stable transfectants of MIN6 cells that overexpressed the type II activin receptor were then developed. The transfected cells (MIN6-ActR cells) expressed ten times more 125I-labeled activin A-binding sites than parental cells and the apparent Kd was 1.15 nM, which was nearly identical to that in parental cells. Affinity cross-linking in MIN6-ActR cells showed that a 90 kDa type II receptor as well as a 52 kDa protein, presumably follistatin, was markedly labeled with 125I-labeled activin A. Although MIN6-ActR cells expressed significant numbers of activin receptors, activin A did not induce immediate calcium-dependent responses in these cells. In contrast, activin A was capable of inducing long-term effects in MIN6-ActR cells; thus, reduction of the glucose concentration in culture medium from 25 to 5.5 mM for 4 days resulted in a remarkable loss of insulin response to glucose stimulation but this decline in response to glucose was prevented by the addition of activin A during culture. In addition, activin A inhibited DNA synthesis in MIN6-ActR cells. Hence, although activin A did not induce calcium-dependent responses, it evoked some calcium-independent effects in MIN6-ActR cells. Taken together, activin A elicits various effects in beta-cells by both calcium-dependent and -independent mechanisms.

Activin Receptors↗
PubMed1996

Longitudinal change in serum cholesterol levels among isolated hypertriglyceridemic cases.

The present study investigated longitudinal change in serum cholesterols of isolated hypertriglyceridemic cases (54 males, 34 females) and age-matched controls (115 males, 98 females) based on a 4-year longitudinal observation. At the baseline, the level of triglyceride was significantly higher in hypertriglyceridemic cases (329 +/- 133mg/dl in males, 274 +/- 76mg/dl in females) than in the controls (81 +/- 18 mg/dl in males, 73 +/- 16mg/dl in females). Further, body mass index (BMI) was also significantly higher than that of the controls. There were no statistical differences in total cholesterol(TC) between the cases (197 +/- 23mg/dl males, 211 +/- 30mg/dl females) and the controls (189 +/- 19mg/dl males, 202 +/- 18mg/dl females). In hypertriglyceridemic cases, both TC and low density lipoprotein plus very low density lipoprotein cholesterols significantly increased between the baseline and the four years later (TC: 197 +/- 23mg/dl to 205 +/- 26mg/dl in males, p < 0.05. 211 +/- 30mg/dl to 227 +/- 44mg/dl in females, p < 0.01), whereas no change was observed in the controls. The BMI of the cases and the controls were unchanged throughout the study period. The present study shows that isolated hypertriglyceridemia with normocholesterolemia proceeds to hypercholesterolemia, which is compatible with endogenous lipoprotein metabolism.

Adult↗
PubMed1996

[Comparison of bone mineral levels in healthy Japanese perimenopausal women measured by dual energy X-ray absorptiometry and ultrasound methods].

One hundred and seventy Japanese perimenopausal women, 44 to 65 years old (average 55.3), living in the Tokyo metropolitan area were evaluated for bone minerals by two methods of measurement--DXA (dual energy x-ray absorptiometry) measured at the 2nd-4th lumbar spine and three areas of proximal femur, and US (ultrasound bone densitometry) measured at the calcaneal area of the foot. Menopausal status was determined by interview, and anthropometric measurements, grip strength and various foot measurements including length, breadth, girth, area, and angles were taken. The relationship between these physical factors and bone minerals measured by DXA and US was considered in comparisons of evaluations of bone mineral condition by these two different methods. The results were as follows: 1) The means of bone mineral density (BMD) at four sites by DXA and of broadband ultrasound attenuation (BUA) by US decreased with age significantly in a graded fashion. The mean of speed of sound (SOS) by US, however, did not show a significant decrease by age. 2) All measurements but one (SOS by US) showed significant differences among three groups of menopausal status (premenopause, < 6 years after menopause, and > or = 6 years after menopause) by ANOVA. 3) Concerning the relationship between physical variables and bone measurements, all measurements for bone mineral showed significant correlations with body weight (positive) and age (negative) except SOS by US. Grip strength had significantly positive correlations to all bone measurements. BUA by US showed strong correlations with several of the foot measurements. 4) Correlations between bone measurements by DXA and US, were all strong and positive particularly in the combinations within the measurement by DXA. 5) Multiple regression analysis of the physical variables to each bone measurement as the dependent variable, showed significant relationship of age (negative) and body weight or BMI (positive) to each bone measurements except for SOS. The foot area remained significant for BUA. The significant relationship of combinations of physical factors that persisted for US were somewhat different from those in DXA. These results indicate that the level of accuracy of measurements of bone mineral by ultrasound may not necessarily be equivalent to that of dual energy x-ray absorptiometry measurements and must be utilized with caution especially in risk factor analysis of osteoporosis.

Absorptiometry, Photon↗
PubMed1996

Blockade of DNA synthesis induced by platelet-derived growth factor by tranilast, an inhibitor of calcium entry, in vascular smooth muscle cells.

The present study was conducted to establish a pharmacological method of controlling growth of vascular smooth muscle cells (VSMC) by blocking calcium entry. In cultured rat VSMC, 1 nM platelet-derived growth factor (PDGF) induced a biphasic elevation of cytoplasmic free calcium concentration, ([Ca2+]c). The second sustained phase of [Ca2+]c was dependent on extracellular calcium. At lower concentrations, PDGF induced oscillatory changes in [Ca2+]c, and reduction of extracellular calcium attenuated the oscillation. An antiallergic compound, tranilast, abolished the sustained phase of [Ca2+]c induced by 1 nM PDGF. Tranilast also inhibited the oscillatory changes in [Ca2+]c induced by 200 pM PDGF. In addition, PDGF-induced calcium influx in the late G1 phase, as assessed by measuring the initial uptake of 45Ca, was inhibited by tranilast in a concentration-dependent manner. Tranilast also inhibited PDGF-augmented DNA synthesis; the ID50 for the inhibition of DNA synthesis was nearly identical to that for calcium influx. Although tranilast blocked PDGF-induced calcium entry, it did not affect PDGF-mediated autophosphorylation of the PDGF receptor, activation of phosphatidylinositol 3-kinase, activation of Ras or mitogen-activated protein kinase. Similarly, PDGF-induced elevation of diacylglycerol was not affected by tranilast. These results suggest that the antiallergic drug tranilast inhibits PDGF-induced DNA synthesis by blocking PDGF-mediated calcium entry. Tranilast may be of use in controlling PDGF-induced DNA synthesis in VSMC.

Animals↗
PubMed1996

[Social factors related to awareness of public health care services among elderly adults].

This article presents findings on the association between social ties and the awareness in elderly of seven services. A total of 1,200 persons aged 60 and over were subjects of an interview survey of when 856 subjects provided necessary data for analysis. Subjects lived in two separate communities, Nerima-Ward (a metropolitan area) and Kashimadai-Cho (a rural area). Social ties were classified into six types: living with a person, contact with child (ren) living separately, contact with friend, contact with neighbor, and participation in a community group. The elderly metropolitan residents were significantly less likely to be aware of a greater number of services. Contacts with neighbor and participation in community group predicted service awareness. There were no regional differences in the effect of those ties on service awareness.

Aged↗
PubMed1996

[Diagnostic cytology for detection of early cancer].

Cytologic methods for detection of early cancers of the uterine cervix, lung and various other organs are discussed. The scraping smear method using a spatula is more effective than the cotton swab or vaginal pool smear method for detection of preinvasive intraepithelial lesions, such as, carcinoma in situ and dysplasias of various degrees of the uterine cervix. The use of sputum specimens pooled for three to five days is recommended for cytologic examination in population screening of lung cancer. Good cytopreparatory techniques, suitable screening and cytodiagnostic classifications of malignancy are also described and emphasized, especially, the importance of properly fixed cytologic material for correct cytopathological diagnosis.

Biopsy↗
PubMed1996

[Examination of the degree of agreement among dental findings used for personal identification (report 5)--canonical correlation between dental findings on dental charts and those on radiographs].

Findings obtained from dental charts and from radiograph taken one year later for the same individuals were examined and classified according to different criteria. Similarities between the two sources investigated by the canonical correlation method. The results obtained were as follows: 1. The correlation coefficient and the squared multiple correlations (R2) were calculated. Consequently, high similarities were seen between the two sources for the mandibular anterior teeth [sequence: see text], maxillary incisor teeth [sequence: see text], mandibular and maxillary first premolar teeth [sequence: see text], and the corresponding teeth of the same jaws. 2. Three roots showed high elucidative values by the canonical correlation method. The first root was understood to be the mandibular incisor factor, the second the maxillary incisor factor, and the third the first premolar factor. This seemed to indicate, that the similarities between the two sources in these regions were very high. 3. A study of the similarities between the two sources was done based on the individual scores of canonical variable loadings calculated in this analysis. High similarities were seen at [sequence: see text] in category 1 (intact & C1) for chart findings and category 1'(intact, C1-C3 & resin filling) for radiographic findings: at [sequence: see text] in category 2 (C2-C4, inlay & filling of repair) for chart findings and category 3'(stump of tooth) for radiographic findings; and at [sequence: see text] in category 3 (complete crown, jacket crown & post crown) for chart findings and category 3'(stump of tooth) for radiographic findings. 4. The present results suggest that if proper case in taken, one set of information can serve as a substitute for the other. In personal identification, higher efficiency may be achieved if this is borne in mind.

Adult↗
PubMed1996

Seroepidemiological study of Toxoplasma infection in central and western regions in Nepal.

The present study was carried out to ascertain the seroprevalence rate in different geographical areas in Central and Western Regions in Nepal. A total of 1,237 serum samples collected from Nuwakot (217), Kathmandu valley (402) and Chitawan (159) districts in Central Region, and Mustang (143), Surkhet (64) and Banke (252) districts in Western Region in Nepal were included in this study. Toxoplasma antibodies were detected by micro-latex agglutination (MLA) and enzyme linked immunosorbent assay (IgM-ELISA) methods. The seropositive rate in Central and Western Regions were found to be 48% and 49%, respectively; with an overall positive rate of 48 percent. Districtwise, the seropositive rate in Nuwakot, Kathmandu valley, Chitawan, Mustang, Surkhet and Banke districts were 38, 46, 64, 51, 67 and 44%, respectively. Interestingly, the relatively newly inhabited Surkhet district in Western Region and Chitawan district in Central Region showed significantly higher seropositive rate compared with those of two other districts in the respective Regions (p < 0.05). Ethnically, Tibeto-Burmans showed higher seropositive rates in Central Region (p > 0.05). In contrast, Indo-Aryans showed higher seropositive rate in Western Region (p > 0.05). Age related increase in seropositivity was observed only in Central Region. One percent of Toxoplasma antibody positive samples also showed Toxoplasma IgM antibody positivity.

Adult↗
PubMed1995

Chlorogenic acid as a natural scavenger for hypochlorous acid.

The effect of chlorogenic acid (CGA) on the killing of Escherichia coli by hypochlorous acid (HOCI) was examined. CGA prevented E. coli from bactericidal action of HOCI in a concentration-dependent manner. HOCI reacted rapidly with CGA. By comparison with the one- and two-electron oxidation products produced by peroxidase and phenolase reactions, respectively, the main product was identified as o-quinone of CGA via the formation of o-semiquinone of CGA as an intermediate The quinone form of CGA reacted further with HOCI to yield unstable product(s).

Blood Bactericidal Activity↗
PubMed1995

The suppression of the N-nitrosating reaction by chlorogenic acid.

N-Nitrosation of a model aromatic amine (2,3-diamino-naphthalene) by the N-nitrosating agent produced by nitrite in acidic solution was inhibited by a polyphenol, chlorogenic acid, which is an ester of caffeic acid quinic acid. Caffeic acid also inhibited the N-nitrosation, but quinic acid did not. 1,2-Benzenediols and 3,4-dihydroxybenzoic acid had inhibitory activities. Chlorogenic acid, caffeic acid, 1,2-benzenediols and 3,4-dihydroxybenzoic acid were able to scavenge the stable free radical, 1,1-diphenyl-2-picrylhydrazyl. Chlorogenic acid was found to be nitrated by acidic nitrite. The kinetic studies and the nitration observed only by bubbling of nitric oxide plus nitrogen dioxide gases indicated that the nitrating agent was nitrogen sesquioxide. The observations showed that the mechanism by which chlorogenic acid inhibited N-nitrosation of 2,3-diamino-naphthalene is due to its ability to scavenge the nitrosating agent, nitrogen sesquioxide. Chlorogenic acid may be effective not only in protecting against oxidative damage but also in inhibiting potentially mutagenic and carcinogenic reactions in vivo.

2-Naphthylamine↗
PubMed1995

Identification of Schizosaccharomyces pombe gene psk1+, encoding a novel putative serine/threonine protein kinase, whose mutation conferred resistance to phenylarsine oxide.

We have identified a novel putative protein kinase-encoding gene from Schizosaccharomyces pombe (Sp), designated psk1+, by using a highly conserved amino acid (aa) sequence motif to design amplification of DNA fragments using PCR. The putative translation product of psk1+ contains 436 aa, with a molecular mass of 49,317 Da. A single psk1+ was identified by genomic Southern blot analysis, and the genomic mapping indicated that psk1+ was localized in Sp chromosome III. Growth of wild-type Sp cells was inhibited by 0.5 microM phenylarsine oxide, a protein tyrosine phosphatase inhibitor, but psk1- cells were relatively resistant to this drug.

Amino Acid Sequence↗
PubMed1995

Effect of dietary chloride on aldosterone synthase induction and angiotensin II receptors in rat adrenals.

Effects of dietary chloride ions on the levels of both cytochrome P-450aldo (CYP11B2) and angiotensin II receptors were examined in rat adrenals. Capsular adrenal CYP11B2 protein levels significantly increased in previously chloride-depleted animals treated with either ammonium- or choline chloride. No changes in CYP11B2 protein levels were detected in previously chloride-depleted rats replenished with either ammonium acetate or choline bromide. The induction of CYP11B2 by chloride-repletion was not concurrent with either increased plasma renin activity or elevated serum potassium levels. None of the above dietary manipulations affected angiotensin II receptor number and affinity, respectively. Treatment of chloride-repleted animals with an angiotensin II receptor antagonist (TCV116) significantly attenuated the increase of CYP11B2 protein levels. In addition, chloride-repletion of previously chloride-depleted animals increased mRNA levels encoding angiotensin II type 1B receptor, but decreased mRNA levels encoding the type 1A form of the receptor. Thus, the presented data are supportive of the notion that the regulation of CYP11B2 expression in the capsular portion of the rat adrenal is, in part, mediated via induction of the angiotensin II type 1B receptor.

Adrenal Glands↗
PubMed1995

Structural studies on a cell wall polysaccharide from Bifidobacterium longum YIT4028.

The major fraction of rhamnogalactan was isolated from the cell wall of Bifidobacterium longum YIT4028 by treatment with N-acetylmuramidase. This polysaccharide was composed of rhamnose and galactose in a molar ratio of about 2:3. The 13C NMR spectrum indicated that it contained a pentasaccharides repeating unit. This observation, and the results of Smith degradation, partial acid hydrolysis and methylation analysis led to the conclusion that its structure is [formula: see text]

Bifidobacterium↗
PubMed1995

Purification and characterization of a fatty acid-activated protein kinase (PKN) from rat testis.

PKN, a novel protein kinase with a catalytic domain homologous to that of the protein kinase C (PKC) family and unique N-terminal leucine-zipper-like sequences, was identified by molecular cloning from a human hippocampus cDNA library [Mukai and Ono (1994) Biochem. Biophys. Res. Commun. 199, 897-904]. Recently we partially purified recombinant PKN from COS7 cells transfected with the cDNA construct encoding human PKN, and demonstrated that the recombinant PKN was activated by unsaturated fatty acids and limited proteolysis [Mukai, Kitagawa, Shibata et al. (1994) Biochem. Biophys. Res. Commun. 204, 348-356]. The present work has focused on the further purification and characterization of PKN from native rat tissue. Immunochemical measurement revealed that PKN was found in every tissue, and was especially abundant in testis, spleen and brain; subcellular fractionation of rat brain showed that half of the PKN was localized in the soluble cytosolic fraction. PKN was purified approx. 8000-fold to apparent homogeneity from the cytosolic fraction of rat testis by DEAE-cellulose chromatography, ammonium sulphate fractionation and chromatography on butyl-Sepharose, heparin-Sepharose, Mono Q and protamine-CH-Sepharose. The enzyme migrates as a band of apparent molecular mass 120 kDa. Using serine-containing peptides based on the pseudosubstrate sequence of PKC-delta as phosphate acceptors, the kinase activity was stimulated several-fold by 40 microM unsaturated fatty acids or by detergents such as 0.04% sodium deoxycholate and 0.004% SDS. In the absence of modifiers, protamine sulphate, myelin basic protein and synthetic peptides based on the pseudosubstrate site of PKCs or ribosomal S6 protein were good substrates for phosphorylation by the kinase. In the presence of 40 microM arachidonic acid the kinase activity of PKN for these phosphate acceptors was increased 2-18-fold. The autophosphorylation activity of purified PKN was partially inhibited by pretreatment with alkaline phosphatase. These properties appear to distinguish PKN from many protein kinases isolated previously.

Amino Acid Sequence↗