Biomedical subjects

S Yoshihara

Publications and source records attributed to S Yoshihara.

At least 55 records · Page 3Linked to original sources

PubMed1999

[Characterization of hepatic bile mucus glycoprotein in hepatolithiasis].

To study the characterization of hepatic bile mucus glycoprotein in hepatolithiasis cases, we isolated glycoprotein from the bile of patients with intrahepatic gallstones by gel filtration and ultracentrifugation. The carbohydrate chains of mucus glycoprotein were released by hydrazinolysis. The properties of the hepatolithiasis carbohydrate chains were compared with those of a control group. The mucus glycoprotein concentration in bile in hepatolithiasis patients (299.9 micrograms/ml) was higher than that in the controls (28.0 micrograms/ml). Both groups had no evident changes in molecular weight or amino acid composition. The quantities of N-Galactosamine and sulfate in the hepatolithiasis group were larger than in those of the control group. Carbohydrate chain lengths in the hepatolithiasis group were shorter than those in the control group. This phenomenon suggests that mucus glycoprotein of the bile in hepatolithiasis patients has a different metabolism and biological function from that of normal bile.

Amino Acids↗

PubMed1999

[Cytomegalovirus infection associated with immunosuppressive therapy in collagen vascular diseases].

OBJECTIVE: We investigated the frequency of cytomegalovirus (CMV) infection during immunosuppressive therapy in collagen vascular disease by using CMV antigenemia assay. METHODS: CMV antigenemia in fifteen patients with collagen vascular disease were analyzed before and one month after immunosuppressive therapy with more than 30 mg/day of prednisolone. RESULTS: CMV antigenemia were detected in 9 patients (60%), however no CMV antigenemia detected in all patients before treatment. In 7 of 9 patients CMV infection occurred such as fever, leucocytopenia, thrombocytopenia, liver injury, interstitial pneumonia. In 2 patients of polymyositis/dermatomyositis, creatine phosphokinase (CPK) levels which had decreased once just after treatment started, elevated again although initial dose of prednisolone continued. After ganciclovir administration because of the positive results of CMV antigenemia, elevated CPK levels were normalized immediately. CONCLUSION: Our results showed that CMV infection occurred with high frequency during immunosuppressive therapy, and might mimic the exacerbation of collagen vascular disease. It is important to differentiate CMV infection from increased activity of collagen vascular disease during the treatment.

Adult↗

PubMed1998

Involvement of hepatic aldehyde oxidase in conversion of 1-methyl-4-phenyl-2,3-dihydropyridinium (MPDP+) to 1-methyl-4-phenyl-5,6-dihydro-2-pyridone.

To obtain direct evidence of the involvement of aldehyde oxidase (AO), a cytosolic molybdoflavoenzyme, in the metabolism of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), we investigated the in vitro metabolism of MPTP and the two-electron-oxidized 1-methyl-4-phenyl-2,3-dihydropyridinium species (MPDP+) by using mouse liver enzyme preparations. Incubation of MPTP with mitochondrial fraction gave exclusively 1-methyl-4-phenylpyridinium (MPP+); this reaction was inhibited by deprenyl, a monoamine oxidase (MAO)-B inhibitor, and KCN. When the mitochondrial fraction was combined with the cytosolic fraction, MPP+ formation was markedly decreased, while a large amount of 1-methyl-4-phenyl-5, 6-dihydro-2-pyridone (MPTP lactam) was newly formed. Incubation of MPDP+ with the cytosolic fraction led to rapid formation of MPTP lactam with concomitant disappearance of the substrate. The cytosol-dependent formation of MPTP lactam was inhibited by known AO inhibitors, such as menadione, norharman, and KCN. The activity of cytosol in MPTP lactam formation was completely duplicated by purified mouse liver AO. These results indicate that AO catalyzes the metabolic conversion of MPDP+, produced from MPTP by MAO-B, to MPTP lactam. This metabolic pathway might be an important detoxification route, averting the formation of toxic MPP+.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed1998

PACAP 1-38 as an inhaled bronchodilator in guinea pigs in vivo.

The effect on total pulmonary resistance (R1) was examined for inhaled PACAP 1-38, PACAP 1-27 and VIP in anesthetized, ventilated guinea pigs. Two minutes after inhalation, PACAP 1-38 (36 +/- 6%), PACAP 1-27 (42 +/- 9%) and VIP (48 +/- 19%) inhibited the increase in R1 (% inhibition of histamine-induced R1 prior to inhalation) caused by histamine i.v., whereas the vehicle (-1 +/- 10%) did not. This inhibitory effect lasted five times longer for PACAP 1-38 (> 50 min) than for PACAP 1-27 and VIP (< 10 min). The inhaled peptides caused no sustained effects on heart rate or blood pressure. Infusion of PACAP 1-38 i.v. dose-dependently inhibited the increase in R1 caused by inhaled histamine and by carbachol i.v..

Administration, Inhalation↗

PubMed1998

A novel long-acting VIP analog in the guinea pig trachea in vitro.

The relaxant effect of a novel VIP analog, [Arg15,20,21Leu17]-VIP-Gly-Lys-Arg-NH2 was compared with that of the original VIP in the same guinea pig trachea precontracted by carbachol in vitro. The VIP analog caused significantly and concentration-dependent relaxation similarly to the original VIP. In contrast to the original VIP, the VIP analog demonstrated a slow onset and offset of action, with more than 90% of its maximum relaxation remaining 6 h after administration. Peptidase inhibition by captopril and phosphoramidon increased the relaxant effect and duration of action for original VIP but not for the VIP analog.

Albuterol↗

PubMed1998

Age-related changes in transiently evoked otoacoustic emissions and distortion product otoacoustic emissions in normal-hearing ears.

Age-related changes in transiently evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) were evaluated in normal-hearing ears. The TEOAE was elicited by a non-linear click with a stimulus level of 82 +/- 1 dB SPL using ILO 88 in 251 normal-hearing ears. The DPOAE at the frequency of 2f1-f2 was measured with stimulus levels of 70 dB SPL (f1) and 60 dB SPL (f2) and with an f2/f1 ratio of 1.2 using ILO 92 in 64 normal-hearing ears. The results obtained showed that TEOAE and DPOAE were decreased with increasing age. Moreover, the same pattern of gradual decrease in TEOAE and in DPOAE suggests the possibility of the same generating mechanism associated with outer hair cells (OHCs).

Acoustic Stimulation↗

PubMed1998

An erratic parasitism found in the lungs of sheep during experimental infection with Fasciola gigantica (Japanese strain).

An erratic parasitism was observed in the lungs of sheep experimentally infected with Fasciola gigantica at autopsy 14 weeks after inoculation. Macroscopically, several hyperaemia of 7.5-12.5 mm in diameter were found on the surface of the lungs. Juvenile flukes detected in the lungs were much smaller than those in the liver of the same sheep. A slight inflammatory reaction was observed in the lungs and it is likely that the flukes had migrated in the pleural cavity for some time. Occasionally, a mixed thrombus with many eosinophils was found in the blood vessels adjacent to the bronchia, although no cough was observed clinically. This suggests that diagnosis of juvenile fluke is difficult not only by parasitological but also serological methods.

Animals↗

PubMed1998

MPO-ANCA-positive crescentic necrotizing glomerulonephritis and tubulointerstitial nephritis with renal eosinophilic infiltration and peripheral blood eosinophilia.

We present the case of a 67-year-old woman with myeloperoxidase (MPO)-antineutrophil cytoplasmic antibody (ANCA)-positive pauci-immune crescentic necrotizing glomerulonephritis and tubulointerstitial nephritis with renal eosinophilic infiltration and peripheral blood eosinophilia. Staining for eosinophil cationic protein indicated that activated eosinophils were involved in the tubulitis, as well as in the glomerular injury. Marked peripheral blood eosinophilia is uncommon in ANCA-positive crescentic necrotizing glomerulonephritis associated with tubulointerstitial nephritis, except in Churg-Strauss syndrome. However, our patient had no clinical history or signs of asthma, no other signs suggestive of allergic diseases, and no histologic findings of granulomas in the kidney, thus failing to fulfill the criteria for Churg-Strauss syndrome.

Aged↗

PubMed1998

Endogenous nitric oxide inhibits bronchoconstriction induced by cold-air inhalation in guinea pigs: role of kinins.

Inhalation of cold air in guinea pigs increases total pulmonary resistance (RL), an effect that is mediated by kinins and tachykinins. Bronchoconstriction induced by bradykinin (BK) inhalation in guinea pigs is markedly inhibited by nitric oxide (NO) release from the airway epithelium. We investigated whether endogenous NO modulates the increase in RL induced by inhalation of cold air. In anesthetized and artificially ventilated guinea pigs pretreated with atropine, cold-air inhalation (13 degrees C in the trachea) for 5 min did not increase RL. Pretreatment with intravenous N(G)-nitro-L-arginine methyl ester (L-NAME) (but not with its inactive enantiomer, D-NAME) increased RL, an effect reversed by L-Arg. The increase in RL induced by cold air after L-NAME was abolished by the tachykinin NK2-receptor antagonist SR 48968 or the kinin B2-receptor antagonist, HOE 140. After administration of SR 48968, inhalation of cold air reduced baseline airway tone. However, after HOE 140, cold-air inhalation did not affect baseline airway tone. L-NAME exaggerated the bronchoconstriction induced by BK. However, L-NAME did not affect capsaicin-induced bronchoconstriction. BK increased cyclic guanosine monophosphate (cGMP) levels in strips of guinea pig trachealis muscle in vitro, whereas the selective tachykinin NK2-receptor agonist [betaAla8]neurokinin A (4-10) was without effect. The present data suggest that bronchoconstriction induced by cold-air inhalation and mediated by kinin and tachykinin release is inhibited by endogenous NO, and that kinins, but not tachykinins or cold air alone, release bronchorelaxant NO.

Air↗

PubMed1998

Effect of a novel PACAP-27 analogue on muscarinic airway responsiveness in guinea-pigs in vivo.

A recent study showed that the novel pituitary adenylate cyclase-activating peptide (PACAP)-27 analogue [Arg15,20,21,Leu17]-PACAP-27-Gly-Lys-Arg-NH2 causes sustained airway smooth muscle relaxation in vitro. This study examined whether this analogue also has bronchoprotective effects, by inhibiting muscarinic airway responsiveness in vivo. Total lung resistance was measured in anaesthetized, tracheostomized and ventilated guinea-pigs. Increasing doses of acetylcholine were given i.v. once before and thereafter repeatedly each hour after intratracheal instillation of either the PACAP-27 analogue or the clinical beta2-agonist bronchodilator salbutamol. Mean arterial blood pressure (MAP) was monitored to detect cardiovascular side-effects. Both the PACAP-27 analogue and salbutamol significantly attenuated the airway responsiveness to acetylcholine. The total inhibitory effect of the PACAP-27 analogue (350 nmol) corresponded to that of salbutamol (35 nmol). The inhibitory effect of salbutamol (35 nmol) peaked during the second hour and disappeared prior to 5 h after administration. In contrast, the corresponding effect of the analogue (350 nmol) gradually increased and peaked during the fifth hour after administration, whereas it did not fade during the observation period. Both the PACAP-27 analogue (350 nmol) and salbutamol (35 nmol) produced a transient decrease in MAP within 6 min after administration. In conclusion, the novel pituitary adenylate cyclase-activating peptide-27 analogue has bronchoprotective properties, by decreasing muscarinic airway responsiveness in guinea pigs in vivo. The time course of its effect is compatible with a more sustained duration of action compared with salbutamol.

Acetylcholine↗

PubMed1998

Seroprevalence and field isolation of bovine immunodeficiency virus.

A seroprevalence study of bovine lentivirus, known as bovine immunodeficiency virus (BIV), was conducted in 12 different dairy herds in Hokkaido, where some herds were a high prevalence of bovine leukemia virus (BLV) infection. Amongst 611 cattle, 28.6% of cattle were BLV-seropositive, and 11.7% of cattle were seropositive for BIV, while 4.2% of cattle were seropositive for both BIV and BLV. For the isolation of BIV, 19 samples of peripheral blood mononuclear cells (PBMC) and one sample of milk-derived leukocytes were prepared from BIV-seropositive cows. These PBMC and leukocyte preparations were then co-cultivated with cc81 cells, a cat cell line transformed by mouse sarcoma virus. BIV was isolated from 17 PBMC and one milk-derived leukocyte samples. The isolated viruses showed slow replication and syncytia formation. Major core antigen, p26 from these isolates were reacted with anti-BIV (American isolate R-29) serum. In addition, proviral DNA was detected in blood and milk samples by nested polymerase chain reaction and subsequent Southern blot hybridization. Nucleotide sequence analysis of the amplified pol gene products showed its 99.0 to 99.7% homology to that of BIV R-29. These results indicate that the Japanese BIV isolates appear to be antigenically and genetically similar to the American R-29. Since BIV was isolated from milk samples, BIV could possibly be transmitted through milk. This is the first report of BIV isolation in Japan.

Amino Acid Sequence↗

PubMed1998

Immunoblot analysis of humoral immune responses to Leucocytozoon caulleryi in chickens.

The humoral antibody responses of chickens infected or immunized with Leucocytozoon caulleryi were analyzed by immunoblot comparing with protection against challenge infection, agar-gel precipitation (AGP) test, enzyme-linked immunosorbent assay (ELISA), and parasitemia. IgG antibodies in the sera from chickens infected with L. caulleryi were found to react with 20-35 bands of approximate molecular weights 25-300 kDa, such as 33, 44, 58, 79, 94, and 141 kDa from 3 to 50 wk after infection. In chickens immunized with schizont antigens from L. caulleryi, several bands were reacted with sera 2 wk after the second immunization, e.g., 36, 58, 71, 81, 97, 112, and 123 kDa. Chickens that recovered from the primary infection showed complete protection against reinfection, whereas immunized chickens showed partial protection against challenge infection. These results suggest that the difference in antibody response to schizont antigen might cause the difference in protection between immunized and infected chickens.

Animals↗

PubMed1997

Identification of a novel nuclear localization signal in Sam68.

Sam68, a nuclear RNA binding protein, binds to Src and is phosphorylated at tyrosine residues in an M-phase specific manner. Here we identified a stretch of 24 amino acid residues in the COOH-terminal portion of Sam68 which function as a nuclear localization signal. This signal sequence bears no apparent homology to any other known nuclear localization sequence. However, this sequence was found to contain a motif, PPXXR (P, Pro; R, Arg), which is conserved in various RNA binding proteins including hnRNP proteins. Replacement of Arg in this motif with Ala abolished the nuclear accumulation of a GFP fusion protein, suggesting that this residue is important in translocating the protein to the nucleus.

3T3 Cells↗

PubMed1997

Involvement of growth hormone as a regulating factor in sex differences of mouse hepatic aldehyde oxidase.

The participation of circulating growth hormone (GH) as a regulator of sex differences in hepatic aldehyde oxidase (AO) activity in ddy mice was examined. The 2- to 3-fold higher activities in adult male mice compared with adult female mice were decreased to the female levels by neonatal pretreatment with monosodium glutamate (MSG) or monosodium aspartate (MSA), either of which is known to reduce circulating GH levels. A decline of the activities in the MSG-treated male mice was restored nearly to the male control levels by subsequent injections of human GH every 12 hr for 7 days. These changes in AO activities in male mice caused by the excitotoxic amino acids were not observed in females. Hypophysectomy markedly decreased hepatic AO activities in male mice and partially in female mice. The activities in hypophysectomized male mice were restored again to levels similar to the control males by intermittent injections of human GH. Administration of testosterone propionate (TP) significantly increased the activities of hepatic AO in intact female mice, but not in MSA-treated or hypophysectomized females. On the other hand, the AO activities in adult male mice were decreased partially by the administration of estradiol benzoate. These results indicate that the pituitary GH is involved as one of the major regulatory factors of sex differences in the activities of hepatic AO in mice and TP also contributes to maintaining the higher activity in male mice mainly through the hypothalamus-pituitary system.

Aldehyde Oxidase↗

PubMed1997

Purification and characterization of hepatic aldehyde oxidase in male and female mice.

To examine whether the hepatic aldehyde oxidases of male and female mice, which exhibit sex-related differences in benzaldehyde oxidation, are qualitatively different, we purified the enzymes from untreated male and female ddy mice and testosterone-pretreated female mice by sequential chromatography of benzamidine-Sepharose 6B and DEAE-5PW columns and characterized the enzymes. Purified enzymes from untreated male and female mice and from testosterone-treated females gave a single protein band at M(r) 265K and M(r) 138K on native and SDS-polyacrylamide gradient gel electrophoresis, respectively. The susceptibilities of the enzymes from both sexes to inhibitors such as menadione, norharman, quinacrine, estradiol, and SKF 525-A were also indistinguishable. However, the K(m) values for benzaldehyde, p-dimethylaminocinnamaldehyde, and 2-hydroxypyrimidine were two- to fourfold higher in the untreated female enzyme than in the untreated male enzyme, while the testosterone-induced female enzyme showed K(m) values similar to those of the male enzyme. These results indicate that the hepatic aldehyde oxidases of the sexes are quite similar with respect to molecular size and susceptibility to inhibitors, but their kinetic properties are somewhat different, suggesting the existence of microheterogeneity in sex differences. It also suggests that treatment of female mice with testosterone might induce the male-type enzyme.

Aldehyde Oxidase↗

PubMed1997

Effect of retained placenta on subsequent bacteriological and cytological intrauterine environment and reproduction in Holstein dairy cows.

To determine the effect of retained placenta on the characteristics of the intrauterine environment in dairy cows, bacteriological and cytological tests were performed on intrauterine perfusion fluid. The rate of cows with more than 70% neutrophils or fewer than 40% lymphocytes in inflammatory cells was 48.0% (12/25), while the rate and with more than 50 bacterial colonies/0.1 ml of perfusate was 96.0% (24/25) at 30 d after parturition. Actinomyces pyogenes was isolated from 56.0% (14/25). At 60 d after parturition, however, these values were significantly improved to 20.0% (5/25), 48.0% (12/25) and 12.0% (3/25), respectively. No significant differences in subsequent reproductive performance were observed between cows with and without retained placenta. The results suggest that injury to the intrauterine environment caused by retained placenta is largely healed by 60 d after parturition.

Journal Article↗

PubMed1997

Characterization of glycosaminoglycans in regenerating canine liver.

BACKGROUND/AIMS: Liver regeneration after partial hepatectomy is accompanied by hepatocyte proliferation and alteration of the extracellular matrix. Glycosaminoglycans, which are components of the extracellular matrix, interact with other matrix components, and are related to hepatocyte growth. The aim of this study was to investigate the relationship between hepatocyte proliferation and changes in glycosaminoglycan. METHODS: Hepatocyte proliferation and changes in glycosaminoglycan were investigated in dogs after 55% partial hepatectomy. Hepatocyte mitosis was investigated by immunohistochemistry using anti-proliferating cell nuclear antigen antibody. The amount of glycosaminoglycan was determined by the carbazole-sulfuric acid method. We used a new method for analysis of glycosaminoglycan chains, involving endo-beta-xylosidase digestion and fluorescence labelling, to investigate the components of glycosaminoglycan. RESULTS: Hepatocyte mitosis was increased after hepatectomy, reaching a peak at postoperative day 7. The total amount of hepatic glycosaminoglycan reached a maximum at 1 to 2 weeks afer hepatectomy, and the ratio of the components showed a concomitant change, the amount of heparan sulfate increasing, and that of chondroitin sulfate/dermatan sulfate decreasing. Increased heparan sulfate has shorter chains at 1 to 2 weeks after hepatectomy. CONCLUSIONS: These results suggest that the transient changes in heparan sulfate with a decreased chain length and chondroitin sulfate/dermatan sulfate and observed during liver regeneration are associated with hepatocyte proliferation.

Animals↗

PubMed1997

Functional type II VIP-PACAP receptors in human airway epithelial-like cells.

VIP-PACAP receptors were characterized in a human airway epithelial-like cell line (Calu-3), Pituitary adenylate cyclase activating polypeptide (PACAP) 1-27, PACAP 1-38, vasoactive intestinal polypeptide (VIP) and the beta 1- and beta 2-adrenoceptor agonist isoproterenol (3 nM-1 microM) increased cAMP concentration dependently. The peptides and isoproterenol displayed similar potencies (range of means pEC50[M]: 6.5-7.1). The maximum increase in cAMP (Emax in % of basal cAMP level) was similar for the peptides (range of means Emax: 2500-5100%). Pretreatment with the peptidase inhibitors captopril (10 microM) and phosphoramidon (1 microM) significantly increased the cAMP response to PACAP 1-38 (to 480% of control) only.

Captopril↗