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H Nishimura

Publications and source records attributed to H Nishimura.

At least 739 records · Page 41Linked to original sources
PubMed1985

Effect of a phenyl group in quaternary ammonium compounds on thiamine uptake in isolated rat hepatocytes.

The inhibitory effect of a phenyl group in quaternary ammonium compounds on thiamine uptake in isolated rat hepatocytes was investigated. The phenyltrimethylammonium ion was a more potent inhibitor than the tetramethylammonium ion, while the dibenzyldimethylammonium ion was the most potent inhibitor of thiamine uptake among those compounds examined. A kinetic study showed that this compound was a competitive inhibitor. The cetyltrimethylammonium ion was a less effective inhibitor than the benzyltrimethylammonium ion, and the palmitoylcholine ion was a weak inhibitor. These results indicate that the lipophilicity of a quaternary ammonium compound is not always correlated with its affinity for thiamine-carrier binding, but the presence of a phenyl group plays a significant role in affinity. The inhibitory effect of the series of (CH3)3N+ (CH2)nC6H5 (n = 0-6) compounds on thiamine uptake in isolated rat hepatocytes was studied. The maximal inhibitory activity occurred at n = 5. These results suggest that the phenyl group in a quaternary ammonium compound has a specific interaction with the thiamine-binding site in rat liver plasma membrane.

Animals↗
PubMed1985

The inhibitory effect of choline and other quaternary ammonium compounds on thiamine transport in isolated rat hepatocytes.

Quaternary ammonium compounds, such as choline and acetylcholine significantly inhibited thiamine uptake in isolated rat hepatocytes. Kinetic analysis using Lineweaver-Burk and Dixon plots of inhibition experiments revealed that choline and acetylcholine were purely competitive inhibitors for thiamine uptake with Ki values of 0.61 mM and 0.31 mM, respectively. Among quaternary ammonium compounds, hemicholinium-3 and curare were the strongest inhibitors, and kinetic studies showed that these compounds were also purely competitive inhibitors with Ki values of 12.5 microM and 4.3 microM, respectively. These results indicate that choline, acetylcholine and their structural analogs share a common binding site with thiamine in isolated rat hepatocytes. On the other hand, choline uptake by isolated rat hepatocytes occurred by a saturable mechanism with a Kt of 162 +/- 3.85 microM and Vmax of 80.1 +/- 1.30 pmol/10(5) cells per min as well as by a nonsaturable mechanism. Thiamine, pyrithiamine, oxythiamine, chloroethylthiamine and dimethialium inhibited choline uptake, while thiamine phosphates such as thiamine monophosphate and thiamine pyrophosphate insignificantly inhibited uptake. Although a Lineweaver-Burk plot of choline uptake in the presence of thiamine showed that thiamine also competitively inhibited choline uptake, a Dixon plot of the inhibition experiment was hyperbolic and indicated that the inhibition of choline uptake by thiamine was 'pseudo-competitive'. On the basis of these results, it is suggested that in isolated rat hepatocytes thiamine and choline do not share common transport sites.

Animals↗
PubMed1985

Effect of aloe lectin on deoxyribonucleic acid synthesis in baby hamster kidney cells.

A homogeneous glycoprotein (mol. wt 40,000) containing 34% carbohydrate was isolated from Aloe arborescens var. natalensis. At a concentration of 5 micrograms/ml, this glycoprotein was shown to stimulate deoxyribonucleic acid (DNA) synthesis in baby hamster kidney (BHK) cells and to have the properties of a lectin which reacts with sheep blood cells. The chemical and physical properties of the glycoprotein (aloe lectin) are also discussed.

Aloe↗
PubMed1985

Variation in the clinical courses of adult T-cell leukemia.

Twenty-nine cases of adult T-cell leukemia were classified into four types according to the clinical features and course: smoldering, chronic, crisis, and acute. Only 2 of 14 patients with the acute type responded to therapy. The four types showed apparent differences in clinical features, complications, and prognosis, suggesting the need for different therapeutic regimens. For smoldering and chronic cases, no chemotherapy is recommended. However, in crisis and acute cases, aggressive chemotherapy is necessary, although the acute type cases showed extremely poor prognosis despite the most aggressive chemotherapy.

Acute Disease↗
PubMed1985

Familial adult T-cell leukemia.

Two siblings who developed adult T-cell leukemia (ATL) are presented. The patient and 7 of 26 healthy family members examined had the serum antibodies against ATL-associated antigens (ATLA). This family study shows that two main routes of transmission of human T-cell leukemia virus (HTLV) may be involved: one is the route from parents to children and the other is horizontal transmission among spouses, especially from husband to wife; the anti-ATLA-positive family is considered to be a high-risk group for ATL.

Adult↗
PubMed1985

Gonadal dysgenesis induced by prenatal exposure to ethinyl estradiol in mice.

Daily oral administration of ethinyl estradiol (0.02, 0.2, or 2.0 mg/kg of body weight) to pregnant Jc1:ICR mice resulted in ovotestis and intra-abdominal testis with persistent Müllerian duct and Wolffian duct in male fetuses and ovarian hypoplasia in female fetuses when it was given from day 11 through day 17 of gestation (before gonadal differentiation in the fetus). The ovotestis consisted of testicular and ovarian portions. In the testicular portion, a few solid seminiferous tubules containing spermatogonia, some with pachytene nuclei with Sertoli cells and compact interstitial tissue including Leydig cells, were seen. In the ovarian portion, pachytene nuclei were seen. The intra-abdominal testis was smaller and contained more spermatogonia per tubule in cross section than the control testis. These findings suggest that in male fetuses ethinyl estradiol affects Sertoli cell differentiation resulting in suppression of Müllerian inhibiting factor. On the other hand, in the ovarian hypoplasia, the primordial follicles and follicular cells in a primordial follicle were significantly decreased in number, and the number of the degenerated primordial follicles was significantly increased. It seems likely that ethinyl estradiol affects the intimate contact between follicular cells and oocytes to cause degeneration of primordial follicles.

Animals↗
PubMed1985

Identification and synthesis of [1-asparagine, 5-valine, 9-glycine] angiotensin I produced from plasma of American eel Anguilla rostrata.

The major peptide produced by incubation of American eel (Anguilla rostrata) plasma with the eel kidney extract was identified as [1-asparagine, 5-valine, 9-glycine] angiotensin I (I). Two minor peptides were also identified as [1-aspartic acid, 5-valine, 9-glycine] angiotensin I (II) and [5-valine, 9-glycine] angiotensin I-(3-10)-octapeptide (III). These structures were further confirmed by comparison of these peptides on high-pressure liquid chromatography (HPLC) and high-performance thin-layer chromatography (HPTLC) with the synthetic peptides and the tryptic and chymotryptic digests of the synthetic and natural angiotensins. In the rat pressor bioassays, the synthetic decapeptides I and II possessed 45.4 and 52.2%, respectively, of the pressor activity of [1-aspartic acid, 5-isoleucine] angiotensin II. The pressor activity of I and II was blocked with the converting enzyme inhibitor captopril. Study of the conversion of asparaginyl decapeptide into aspartyl decapeptide in eel plasma indicated that the presence of thimerosal (sodium ethylmercurithiosalicylate) in the incubation mixture inhibited the conversion of I into II. These results suggest that (a) I is the natural form of angiotensin inherent in the American eel while II may be formed during incubation with plasma; (b) eel plasma contains an enzyme which is capable of converting asparaginyl angiotensins into aspartyl angiotensins; and (c) pressor activity of I and II is due to their conversion into the corresponding octapeptides. In a previous work when thimerosal was not included in the incubation mixture, the major peptide produced by incubation of Japanese eel (Anguilla japonica) plasma with its kidney extract was identified as II. (Y. Hasegawa, T. Nakajima, and H. Sokabe, 1983, Biomed. Res. 4, 417-420).

Angiotensin I↗
PubMed1985

Ampicillin concentrations in human serum, gingiva, the mandibular bone, and dental follicle following a single oral administration.

Ampicillin (ABPC) concentrations in human serum, gingiva, the mandibular bone, and dental follicle after a single oral administration of ampicillin (500 mg) were assayed by the agar diffusion (paper disc) method. The peak times of all specimens were identical, being 120 min after administration. The peak concentrations of the respective specimens were 2.01 micrograms/ml, 1.03, 0.34, and 0.72 micrograms/g, respectively. The concentration ratios of gingiva, the mandibular bone, and dental follicle to their corresponding serum at the peak time were 0.51, 0.16, and 0.35, respectively.

Administration, Oral↗
PubMed1985

Concentrations of ampicillin and cefadroxil in human serum and mixed saliva following a single oral administration of talampicillin and cefadroxil, and relationships between serum and mixed saliva concentrations.

The concentrations of ampicillin (ABPC) from talampicillin (TAPC) and cefadroxil (CDX) in serum and mixed saliva were assayed by the thin layer disc plate method. Talampicillin and cefadroxil (500 mg) were given by a single oral administration. The relationships between serum and mixed saliva ampicillin and cefadroxil concentrations were evaluated in the paired specimens collected from 10 different persons, respectively. The means of concentration ratios of mixed saliva to serum ampicillin and cefadroxil were 0.006 +/- 0.003 and 0.025 +/- 0.010 (mean +/- SD), respectively. Significant correlation coefficients between mixed saliva and serum concentrations were found for both ampicillin and cefadroxil, which were r = 0.78, P less than 0.001, and r = 0.67, P less than 0.001, respectively.

Adult↗
PubMed1985

Incorporation of glycerol in the organ of Corti: predominance in hair cells and effects of kanamycin.

A biochemical study revealed that [3H]glycerol was incorporated into various kinds of phospholipids in the guinea pig cochlea. The sites of incorporation of [3H]glycerol injected into the scala tympani were localized autoradiographically. The most active incorporation occurred in the hair cells, especially in the outer ones, followed by the inner ones and the nerve endings attached to hair cells. Glycerol incorporation into hair cells appeared to increase as the apex was approached. Chronic intoxication with kanamycin selectively suppressed glycerol incorporation in the hair cells. The site of glycerol incorporation shown by the present autoradiographic study is likely to reflect the site of phospholipid synthesis. Autoradiographic studies could constitute a new approach to understanding the possible involvement of phospholipid metabolism in the function and pathology of the cochlea.

Animals↗
PubMed1985

Left ventricular diastolic function of spontaneously hypertensive rats and its relationship to structural components of the left ventricle.

Left ventricular (LV) diastolic function was investigated in three different age groups (15, 28 and 50 weeks) of paired spontaneously hypertensive (SHR) and normotensive (WKY) rats under pentobarbital anaesthesia. A time constant of LV pressure decay, represented by T, was used as an index of LV relaxation. We assessed the relationship between haemodynamic parameters and LV structural components as quantified by microspectrophotometry (MSP), using multivariate analysis. T was significantly prolonged in the 28 and 50 week old SHR compared with their normotensive counterparts (P less than 0.05 and P less than 0.01, respectively). T was prolonged by volume loading but was not affected with afterload elevation by angiotensin infusion in all age groups of the SHR and WKY. LV wall thickness was greater in the SHR at all ages and was positively correlated with T (r = 0.42, P less than 0.05). A significant correlation was found between the increase in cardiac muscle fibre and collagen, the decrease in elastin and glycoprotein, and T on multivariate analysis (r = 0.53, P less than 0.05). We conclude that LV relaxation of SHR is disturbed from a relatively young age (28 weeks), for which we consider myocardial hypertrophy and LV structural changes found by MSP as being responsible.

Animals↗