Search PubMed⌕ Search

Biomedical subjects

S Yoshimoto

Publications and source records attributed to S Yoshimoto.

At least 73 records · Page 4Linked to original sources
PubMed1991

Potentiating effect of NH4Cl on vasoconstriction in rat aorta.

The effect on the vasocontractile response of pretreatment with NH4Cl at a concentration (10 mM) that made almost no change in the resting tension was investigated using aortic strips from rats. NH4Cl pretreatment for 10 min significantly potentiated strip contractions induced by KCl (less than or equal to 30 mM), BAY K 8644 (0.1 microM) and phenylephrine (0.01 microM). This potentiating action of NH4Cl was eliminated in presence of nifedipine (1 microM). KCl (14.7 mM)-stimulated 45Ca uptake in rat aorta was significantly potentiated by pretreatment with NH4Cl (10 mM) for 10 min, but this NH4Cl effect was also eliminated in the presence of nifedipine. These results suggest that NH4Cl potentiates contractions induced by KCl and agonists in rat aorta by facilitating calcium influx through the nifedipine-sensitive calcium channel.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1991

The role of cerebral microvessel endothelium in regulation of cerebral blood flow through production of endothelin-1.

We have previously reported the production of endothelin-1 (ET-1) by the cerebral microvessel endothelia and suggested an important role of ET-1 and microvessel endothelia in the regulation of local blood flow within the brain. In the present study, radioimmunoassay of ET-1 revealed that ET-1, produced by cultured cerebral microvessel endothelia grown on a filter, is released mainly to the basal side (corresponding to the basement membrane side), not to the apical side (corresponding to the vascular lumen side). This might indicate that ET-1 constricts arterioles locally at the same place where it is produced by endothelia. The present results also show that cultured cerebral microvessel endothelia produce less ET-1 under low oxygen pressure and that they produce more ET-1 under low carbon dioxide pressure. Taken together, our results may suggest that the negative feedback regulation of cerebral blood flow through oxygen and carbon dioxide pressure is mediated by ET-1 produced locally by cerebral microvessel endothelia.

Capillaries↗
PubMed1991

Effect of carbon dioxide and oxygen on endothelin production by cultured porcine cerebral endothelial cells.

We have previously reported the production of endothelin, a potent vasoconstrictor peptide, by porcine cerebral microvessel endothelia and suggested its important role in the regulation of local blood flow within the brain. In our present study, radioimmunoassay with anti-porcine endothelin antiserum revealed that endothelin, produced by cerebral microvessel endothelia grown on a filter, is released mainly to the basement membrane side, not the vascular lumen side. This finding suggests that endothelin constricts arterioles locally where it is produced by endothelia. We also found that cerebral microvessel endothelia produce less endothelin under low oxygen pressure and more endothelin under low carbon dioxide pressure. Our results suggest that endothelin has a role in the regulation of cerebral blood flow in response to oxygen and carbon dioxide pressure.

Animals↗
PubMed1991

Effects of physical exercise and cold stimulation on serum testosterone level in men.

The concentrations of testosterone (TS) and other related hormones in serum were examined before and after physical exercise with a bicycle ergometer (90 Watts, 20 min.) and a cold water stimulation in 32 19-year-old males. While exercising, the serum TS level significantly increased by 20.8% (p less than 0.05), the luteinizing hormone (LH) level by 3.6% (p less than 0.05) and noradrenaline (NA) level by 140.0% (p less than 0.01). During cold water stimulation, TS decreased by 10.0%, LH increased by 22.1% and NA decreased by 23.8%. Based on changes in hormone levels within the individual during the loads. there was a significant positive correlation coefficient (r) between TS and LH, and between TS and NA, with r (TS-LH) = 0.399 (p less than 0.05) and r (TS-NA) = 0.481 (p less than 0.05) for physical exercise, while r (TS-LH) = 0.403 (p less than 0.05) and r (TS-NA) = 0.431 (p less than 0.05) for cold water stimulation, respectively. These results suggest that physical exercise increases TS level in serum by increasing LH and NA levels, but these tendencies were not found with cold water stimulation.

Adult↗
PubMed1991

[A case of rush dust (IGUSA-SENDO) pneumoconiosis with a large conglomerate mass shadow].

A 61-year-old woman, who had engaged in "tatami" mat production for 20 years, showed a gradually increasing large conglomerate mass shadow associated with small irregular opacities on chest X-ray film. Transbronchial lung biopsy revealed findings consistent with pneumoconiosis, with no suggestion of pulmonary tuberculosis or lung cancer. After 6 years' observation, right upper lobectomy was performed because the mass shadow was still increasing in size. Histological examination revealed a well-defined large mass composed of numerous macrophages containing abundant silicate minerals and fibroblasts proliferating in storiform fashion. No evidence of tuberculosis or malignancy has ever been detected. These findings are compatible with the previously reported pathological findings of "IGUSA-SENDO" pneumoconiosis; however, PR4 type "IGUSA-SENDO" pneumoconiosis has never been previously reported. This is the first reported case of PR4 type "IGUSA-SENDO" pneumoconiosis.

Female↗
PubMed1991

[In vitro activities of newly developed quinolones, fleroxacin, lomefloxacin and sparfloxacin against Mycobacterium tuberculosis].

In vitro antituberculous activities of three newly developed quinolones, fleroxacin (FLRX, AM-833), lomefloxacin (LFLX) and sparfloxacin (SPFX, AT-4140) were evaluated in comparison to that of ofloxacin (OFLX) using M. tuberculosis strains isolated from patients and the Ogawa egg medium. SPFX was apparently more active than OFLX, but both FLRX and LFLX were less active. SPFX inhibited completely the growth of all 20 strains of M. tuberculosis isolated from patients who were not previously treated with OFLX in a concentration of 1.25 micrograms/ml. However, this agent inhibited the growth of only 4 strains (28.6%) of 14 OFLX-resistant M. tuberculosis in a concentration of 1.25 micrograms/ml, suggesting a partial cross-resistance between SPFX and OFLX.

Anti-Infective Agents↗
PubMed1990

Cerebral microvessel endothelium is producing endothelin.

Endothelin, a potent vasoconstrictor peptide, was recently isolated from the supernatant of the cultured endothelia of the porcine aorta and is now supposed to be the most likely candidate for the endothelium-derived contractile factor (EDCF), which is responsible for the endothelium-dependent vasoconstriction by various stimuli. In this study, the production of endothelin by the endothelia of porcine cerebral microvessels was revealed by the Northern blot analysis with porcine endothelin cDNA probe and the enzyme-linked immunosorbent assay (ELISA) with anti-porcine endothelin antibody. Our results raise the possibility that the endothelia of cerebral microvessels regulate the local blood flow within the brain through the production of endothelin.

Animals↗
PubMed1990

Structural characterization of the isoenzymatic forms of human myeloperoxidase: evaluation of the iron-containing prosthetic group.

Myeloperoxidase (MPO) from human neutrophils has been purified and found to exist in three isoenzymatic forms, resolved by ion exchange chromatography. In addition to differences in subunit size and cellular compartmentalization of the isoenzymes, differences have been reported in their activity and susceptibility to inhibition. The structural basis of these isoenzymes is unclear; we attempted to further define their functional characteristics and structural identity. First, we measured respective enzymatic activity using a panel of substrates; MPO I was found to have lower activity with some substrates (pyrogallol, guaiacol, potassium iodide [KI]), but similar activity to the other isoenzymes with 4-aminoantipyrine. These studies confirm that MPO I is enzymatically distinct from MPO II and MPO III. Next, we examined the structural basis of these differences by evaluating the iron-containing prosthetic group in each form using electron paramagnetic resonance (EPR) and determination of the pyridine hemochrome. No significant difference between the isoenzymes was noted in these parameters, suggesting that the prosthetic group is the same in each protein. The cause for any difference in enzymatic activity must lie then in variations extrinsic to the heme, and based on previous studies of the gene and protein analysis, the posttranslational modification of MPO must account for these isoenzymatic species.

Electron Spin Resonance Spectroscopy↗
PubMed1990

Effect of age on contractile response to angiotensin II in rat aorta.

The effects of aging on contractile response to angiotensin II and tachyphylaxis to it were investigated using aortic strips from rats aged 1.5, 4 and 22 months. Whether the endothelium was present or not, the contractile response to angiotensin II was greater and tachyphylaxis to it was less in 1.5-month-old rats than in 4- and 22-month-old rats. The differences between 4- and 22-month-old rats were not significant. Removal of the endothelium enhanced angiotensin II-induced maximal contraction and depressed the tachyphylaxis, these endothelial effects being greater in 4- rather than in 1.5-month-old rats. When the contractile force of angiotensin II was adjusted to a similar level for 1.5- and 4-month-old rats, the endothelial effect on the tachyphylaxis was greater in the 4-month-old rats, but no significant difference was noted in the endothelial effect on the contractile force. These results suggest that during growth, the contractile response of rat aorta to angiotensin II decreases while the endothelial effect on it increases.

Acetylcholine↗
PubMed1990

Relation of serum and erythrocyte magnesium levels to blood pressure and a family history of hypertension. A follow-up study in Japanese children, 12-14 years old.

Serum and erythrocyte magnesium concentrations (S-Mg, E-Mg) were measured in 122 junior high school students followed up for two years from 12 to 14 years of age, and the relationship to blood pressure and a family history of hypertension were investigated. The subjects who had high S-Mg and E-Mg levels at the first examination two years prior tended to show high levels after this follow-up. There were significant positive correlations between two intraindividual values of S-Mg and E-Mg. A similar tendency was found for blood pressure. Tracking phenomena were observed with these measures. The subjects who had high E-Mg levels at the first examination showed no blood pressure elevation during the two-year period. The subjects with a family history of hypertension [FH(+)] showed a higher degree of blood pressure rise during two years than those with no family history [FH(-)], with a significant difference in systolic blood pressure at the age of 14. E-Mg tended to be lower in the FH(+) group than in the FH(-) group with a significant difference in 14-year-old girls. These results suggest that a hereditary predisposition to hypertension is related to magnesium metabolism and that intracellular magnesium deficiency may influence blood pressure elevation in the FH(+) children.

Adolescent↗
PubMed1990

Relationship between molecular structures of sugars and their ability to stimulate the release of glucagon-like peptide-1 from canine ileal loops.

The structure-activity relationship of sugars inducing secretion of glucagon-like peptide-1 from the gut was examined using intestinal loops prepared from the terminal portion of the ileum of dogs. The plasma glucagon-like peptide-1 concentration in a mesenteric vein draining only the looped region of the intestine was increased after infusion of 139 mmol/l solutions of D-glucose, D-galactose, D-glucuronic acid, 3-0-methyl-D-glucose, maltose, sucrose or maltitol into the intestinal lumen, but not after infusion of solutions of D-fructose, D-fucose, D-mannose, D-xylose or lactose. The increases in plasma glucagon-like peptide-1 concentration correlated with the corresponding increases in glucagon-like immunoreactivity induced by these sugars. The plasma glucose level of the regional mesenteric vein increased significantly from the basal level after instillation of D-glucose, but not after instillation of other sugars. It is suggested that cells of the gut have a glucose sensor for release of products of the glucagon gene and that this sensor has specific steric requirements. The sugars that induced glucagon-like peptide-1 release share the molecular features of electron density near C(6), an equatorial hydroxyl at C(2), and an axial hydroxyl at C(1), which could account for their recognition by the glucose sensor to initiate the releases of glucagon-like peptide-1 and glucagon-like immunoreactivity.

3-O-Methylglucose↗
PubMed1990

[Discriminate function of diabetes mellitus (DM) for screening test by serum 3 lipids and glucose].

The purpose of this study was to establish a program to differentiate diabetic patients in computerized health check data using serum lipid test data. We selected 4 items (TC, FC, TG and Glu) as a marker of clusters for further study on the strength of data obtained from cluster analysis using chemical data obtained on 134 patients. Next we tried principal analysis of the 4 items and computed parameters of component 1 & component 2, and obtained a function (D) to discriminate DM. Function (D) is read from comp. 1 and comp. 2. Comp. 1 = (0.89 x TC + 0.95 x FC + 0.75 x TG + 0.24 x Glu) Comp. 2 = (-0.26 x TC -0.21 x FC + 0.27 x TG + 0.93 x Glu) D = (0.2 x comp. 1 + comp. 2-160) DM patients show D greater than = 0 and non-DM patients D less than 0. We applied data on 587 patients (including of 43 DM) incorporating function (D) to check the property. The results proved it useful as a screening test for diabetic patients. The parameters of function (D) are influenced by inter-laboratory differences. However, our parameters were still effective. Data obtained from other laboratories incorporating our parameter gave a diagnostic quality of more than 70%.

Blood Glucose↗
PubMed1989

Identification of glucagon-like peptide-1(7-36) amide in rat brain.

Acid-urea extract of rat brain was examined by glucagon-like peptide-1 (GLP-1) specific radioimmunoassay. A single peak was observed which co-eluted with GLP-1(7-36)amide on gel filtration and anion exchange chromatography. In contrast, GLP-1(1-37) was not detected under our experimental conditions. The fact that GLP-1 (7-36)amide, but not GLP-1(1-37), was present in rat brain suggests that preproglucagon was processed in the brain in the same manner as in the intestine and not as in the pancreas.

Animals↗
PubMed1989

[Group therapy for periodontal disease. 1. Practical application of CPITN and the effects of group therapy].

The purpose of this study was to determine the oral conditions in bakery workers (473 subjects) in addition to the screening system of O'Leary and CPITN, designed for rapid recording of the level of periodontal treatment needs, and to evaluate the periodontal treatments, managed by professional cleaning (scaling) and oral hygiene instruction. The assessment of the prevalence and severity of periodontal disease and resultant treatment needs in this group showed the characteristics of chronic periodontal disease in an advanced stage in persons aged 25-29 and 50-54. 228 patients were selected for treatment for nine months and examined accurately for their periodontal condition. 137 patients continued the following group therapy three times and were reevaluated. Following the group therapy, the oral hygiene status and subjective symptoms of bleeding were improved in all groups, the effectiveness of the treatment on sextants, scoring cord three, four, showed markedly high. To achieve the treatment with few individual appointments, it is necessary to increase our knowledge of how these groups live, depending on the diversity of life style and the differences in ethnic consciousness.

Adult↗
PubMed1989

[Six cases of HTLV-I associated bronchiolo-alveolar disorder (HABA)].

A new clinicopathological state related to HTLV-I infection was found in patients with diffuse panbronchiolitis (DPB) and idiopathic interstitial pneumonia (IIP). This specific state with chronic and progressive respiratory symptoms caused by bronchiolar or alveolar disorder was characterized by smoldering adult T-cell leukemia or the HTLV-I carrier state known as HTLV-I associated bronchiolo-alveolar disorder (HABA). The clinical features of 5 cases with the bronchiolar type of HABA and one case with alveolar type of HABA were described and were compatible with the criteria of DPB and IIP, respectively. Long-term subclinical infection of HTLV-I was suspected to play an important role in the pathogenesis of HABA. Furthermore, the investigation of HABA might yield a clue to the unknown etiology of DPB and IIP.

Adult↗
PubMed1988

An epidemiological study of plasma renin activity in schoolchildren in Japan: distribution and its relation with family history of hypertension.

Plasma renin activity (PRA) was determined in a group of 610 Japanese schoolchildren aged 10-14 years in order to investigate the relationship between PRA distribution and a family history of hypertension. Plasma renin activity was higher in the subjects with a family history of hypertension (FH+) than in those without a family history of hypertension (FH-). Systolic blood pressure (SBP) was also higher in the FH+ group than in the FH- group. The FH- group showed a significant negative correlation between PRA and SBP (boys, r = -0.254, P less than 0.01; girls, r = -0.225, P less than 0.01), whereas the FH+ group showed no correlation between PRA and blood pressure. These results suggested that schoolchildren with a family history of hypertension might have an enhanced renin-aldosterone (R-A) system, resulting in elevation of blood pressure.

Adolescent↗