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Biomedical subjects

Y Okano

Publications and source records attributed to Y Okano.

At least 73 records · Page 4Linked to original sources
PubMed1998

Human UDP-galactose 4' epimerase (GALE) gene and identification of five missense mutations in patients with epimerase-deficiency galactosemia.

The galactosemias are a series of three inborn errors of metabolism caused by deficiency of any one of the three human galactose-metabolic enzymes: galactokinase (GALK), galactose-1-phosphate uridyl transferase (GALT), and UDP-galactose 4' epimerase (GALE). We report here the characterization of the entire coding sequence of the GALE gene and screening for mutations in epimerase-deficient individuals. The human GALE gene is about 4 kb in size and is divided into 11 exons on chromosome band 1p36. We have identified five mutations in the GALE gene of epimerase-deficient galactosemia patients. The patients were either homozygotes or compound heterozygotes for mutations. These results confirm that epimerase-deficiency galactosemia is the result of missense mutations in the GALE gene and indicate that the disease is characterized by extensive allelic heterogeneity.

Base Sequence↗
PubMed1998

Usefulness of per-rectal portal scintigraphy with Tc-99m pertechnetate for galactosemia in infants.

Galactosemia discovered by newborn screening is rarely caused by enzyme deficiency. It has recently been reported that among patients without enzyme deficiency portosystemic shunting may be a cause of galactosemia in some patients. We did per-rectal portal scintigraphy in patients with such galactosemia detected during screening of newborns to examine the usefulness of this method for the diagnosis of portosystemic shunts via the inferior mesenteric vein. The subjects were eight neonates with galactosemia without enzyme deficiency detected during screening. A solution containing technetium-99m pertechnetate was instilled into the rectum, and serial scintigrams were taken while radioactivity curves for the liver and heart were recorded sequentially. The per-rectal portal shunt index was determined by calculating the ratio for counts of the liver to counts for the heart integrated for 24 seconds immediately after the appearance of the liver time-activity curve. A portosystemic shunt was detected in both of the patients with a shunt index of 30% or more, but not in the six patients with a shunt index less than 30%. The blood galactose levels of these six patients later entered the reference range. This method is noninvasive and there is little exposure to the radionuclide. It seemed to be useful for the diagnosis of portosystemic shunt in newborns with galactosemia without enzyme deficiency.

Child, Preschool↗
PubMed1998

Possible involvement of cysteine and histidine residues in the (NH4+ + Na+)-activated ATPase of an anaerobic alkaliphile, Amphibacillus xylanus.

Effect of various inhibitors on the (NH4+ + Na+)-activated ATPase of an anaerobic alkaliphile, Ep01(a strain of Amphibacillus xylanus), was examined. Among the chemicals tested, the enzyme was drastically inactivated by p-chloromercuribenzoic acid and diethyl pyrocarbonate. The ATPase activity of the enzyme, which was inactivated by p-chloromercuribenzoic acid and diethyl pyrocarbonate, was remarkably restored by beta-mercaptoethanol and hydroxylamine, respectively, suggesting the involvement of cysteine and histidine residues in the enzyme activity. Analysis of the inhibition kinetics by diethyl pyrocarbonate indicated that modification of a single histidine residue per ATPase molecule was sufficient to inactivate the enzyme.

Adenosine Triphosphatases↗
PubMed1998

Differential role of catalase and glutathione peroxidase in cultured human fibroblasts under exposure of H2O2 or ultraviolet B light.

The purpose of this study was to elucidate the differential contribution of catalase and glutathione peroxidase (GSH-Px) to H2O2 scavenging in cultured human dermal fibroblasts. Responses of the cells in terms of both enzyme activities were examined by using two sorts of inhibitors, 3-amino-1H-1,2,4-triazole (AT) for catalase and DL-buthionine-[S,R]-sulfoximine (BSO) for GSH-Px, under exposure to H2O2 or ultraviolet (UV) B radiation. AT treatment resulted in a decrease in H2O2 scavenging activity, while BSO treatment did not affect H2O2 scavenging. When fibroblasts were exposed to a low concentration of H2O2 (100 microM). AT treatment resulted in a significant decrease in cell survival, but BSO treatment did not affect survival. At higher concentrations of H2O2 ranging from 500 microM to 1 mM, BSO-treated fibroblasts showed reduced survival. In addition, AT treatment was much more cytotoxic in the presence of UVB than BSO treatment. The intracellular levels of H2O2 in fibroblasts treated with AT or BSO were also determined. BSO-treated cells showed similar H2O2 levels to control cells, but the intracellular H2O2 levels of AT-treated fibroblasts were 1.4-fold higher than found in control cells. These results with human dermal fibroblasts indicate that catalase acts as a primary defence against oxidative stress from exogenous or endogenous H2O2 at low concentrations. In contrast, GSH-Px helps protect the cell from damage during exposure to high concentrations of H2O2.

Amitrole↗
PubMed1998

Molecular characterization of phenylketonuria in Japanese patients.

We characterized phenylalanine hydroxylase (PAH) genotypes of Japanese patients with phenylketonuria (PKU) and hyperphenylalaninemia (HPA). PKU and HPA mutations in 41 Japanese patients were identified by denaturing gradient gel electrophoresis and direct sequencing, followed by restriction fragment length polymorphism analysis to find a large deletion involving exons 5 and 6. Of 82 mutant alleles, 76 (92%) were genotyped showing 21 mutations. The major mutations were R413P (30.5%), R243Q (7.3%), R241 C (7.3%), IVS4nt-1 (7.3%), T2781 (7.3%), E6nt-96A-->g (6.1%), Y356X (4.9%), R111X (3.7%), and 442-706delE5/6 (2.4%). Eight new mutations (L52 S, delS70, S70P, Y77X, IVS3nt-1, A132 V, W187 C, and C265Y) and a polymorphism of IVS10nt-14 were detected. In vitro PAH activities of mutant PAH cDNA constructs were determined by a COS cell expression system. Six mutations, viz., R408Q, L52 S, R241 C, S70P, V388 M, and R243Q, had 55%, 27%, 25%, 20%, 16% and 10% of the in vitro PAH activity of normal constructs, respectively. The mean pretreatment phenylalanine concentration (0.83+/-0.21 mmol/l) of patients carrying the R408Q, R241 C, or L52 S mutation and a null mutation was significantly lower (P<0.0005) than that (1.99+/-0.65 mmol/l) of patients with both alleles carrying mutations associated with a severe genotype. Simple linear regression analysis showed a correlation between pretreatment phenylalanine concentrations and predicted PAH activity in 29 Japanese PKU patients (y=31.9-1.03x, r=0.59, P<0.0001). Genotype determination is useful in the prediction of biochemical and clinical phenotypes in PKU and can be of particular help in managing patients with this disorder.

Animals↗
PubMed1998

Plasma brain natriuretic peptide levels increase in proportion to the extent of right ventricular dysfunction in pulmonary hypertension.

OBJECTIVES: This study sought to investigate the influence of right ventricular (RV) hemodynamic variables and function on the secretion of brain natriuretic peptide (BNP) in patients with isolated RV overload. BACKGROUND: Plasma BNP is known to increase in proportion to the degree of left ventricular (LV) overload. However, whether BNP secretion is also regulated in the presence of RV overload remains unknown. METHODS: Plasma BNP and atrial natriuretic peptide (ANP) levels in the pulmonary artery were measured in 44 patients with RV overload: 18 with RV volume overload (RVVO) due to atrial septal defect and 26 with RV pressure overload (RVPO) due to primary or thromboembolic pulmonary hypertension. Right heart catheterization was performed in all patients. RV and LV ejection fraction, myocardial mass and volume of the four chambers were determined by using electron beam computed tomography. RESULTS: Although both plasma BNP and ANP levels were significantly elevated in patients with RV overload compared with values in control subjects, plasma BNP and the BNP/ANP ratio were significantly higher in patients with RVPO than with RVVO (BNP 294 +/- 72 vs. 48 +/- 14 pg/ml; BNP/ANP 1.6 +/- 0.2 vs. 0.8 +/- 0.2, both p < 0.05). Plasma BNP correlated positively with mean pulmonary artery pressure (r = 0.73), total pulmonary resistance (r = 0.79), mean right atrial pressure (r = 0.79), RV end-diastolic pressure (r = 0.76) and RV myocardial mass (r = 0.71); it correlated negatively with cardiac output (r = -0.33) and RV ejection fraction (r = -0.71). Plasma BNP significantly decreased from 315 +/- 120 to 144 +/- 54 pg/ml with long-term vasodilator therapy (total pulmonary resistance decreased from 23 +/- 4 to 15 +/- 3 Wood U). CONCLUSIONS: Plasma BNP increases in proportion to the extent of RV dysfunction in pulmonary hypertension.

Adult↗
PubMed1998

Noninvasive differential diagnosis between chronic pulmonary thromboembolism and primary pulmonary hypertension by means of Doppler ultrasound measurement.

OBJECTIVES: The purpose of this investigation was to differentiate chronic pulmonary thromboembolism (CPTE) from primary pulmonary hypertension (PPH) by using noninvasive Doppler ultrasound techniques. BACKGROUND: A recent investigation in our laboratory has indicated that the pulmonary artery (PA) pressure waveform conveys significant information that can be used to differentiate CPTE from PPH. Pulse pressure was markedly larger in CPTE than in PPH, indicating that the major occlusive site is central in CPTE and peripheral in PPH. METHODS: In 19 patients with CPTE and 16 patients with PPH, we estimated PA systolic pressure and diastolic pressure from the velocities of tricuspid regurgitation and pulmonary regurgitation, respectively. RESULTS: Estimated systolic pressure was not significantly different between CPTE and PPH (mean [+/-SD] 81+/-20 and 79+/-21 mm Hg, respectively, p=NS). Pulse pressure normalized by systolic pressure was higher in CPTE than in PPH (0.82+/-0.05 vs. 0.63+/-0.10, respectively, p < 0.01). Pulse pressure normalized by mean pressure was also higher in CPTE than in PPH (1.65+/-0.30 vs. 0.94+/-0.25, respectively, p < 0.01). Receiver operating characteristic analysis indicated that pulse pressure normalized by systolic pressure separated CPTE from PPH, with a sensitivity of 0.95 and a specificity of 1.00. Pulse pressure normalized by mean pressure also separated them, with a sensitivity of 0.95 and a specificity of 1.00. CONCLUSIONS: Normalized pulse pressures estimated from Doppler ultrasound measurements enable us to noninvasively differentiate between CPTE and PPH.

Adult↗
PubMed1998

Expression of GTP-binding proteins and protein kinase C isozymes in platelet-like particles derived from megakaryoblastic leukemia cells (MEG-01).

The expression of the various GTP-binding proteins and protein kinase C (PKC) in the platelet-like particles produced by MEG-01 cells was analyzed by RT-PCR and immunoblotting. We selected 14 human low Mr GTPbinding proteins (LMW-GPs) and nine PKCs expressed in platelets and/or megakaryocytes, and designed specific primer pairs for the proteins. RT-PCR analysis revealed that the particles express the mRNAs of many LMW-GPs such as rap 1A, rap 1B, rap 2B, ral A, rho A, rac 1, rac 2, Cdc 42, rab 1, rab 3B, rab 6, ram/rab 27 and ran . By immunoblotting analysis, Rap1, RhoA, Rac, Cdc42, Rab6 and Rab8 were identified in the particles. As for PKCs, the particles were observed to express the mRNAs of PKC-alpha,-beta I, -beta-II, -delta, epsilon, eta and theta, but not-gamma and zeta. Using immunoblot analysis, PKC-beta I, -beta II and zeta were shown to exist in the particles, although the contents were lower than those in platelets. Furthermore, the presence of Gi2-alpha, a heterotrimeric G protein that is the major pertussis toxin substrate in human platelets, and beta subunits was observed in the particles. Taken together, the particles possess some similarity to human platelets based on the expression profiles of GTP-binding proteins and PKCs.

Journal Article↗
PubMed1998

Identification and characterization of STK12/Aik2: a human gene related to aurora of Drosophila and yeast IPL1.

Mutations in aurora of Drosophila and related Saccharomyces cerevisiae IPL1 protein kinases are known to cause abnormal chromosome segregation. We earlier isolated a cDNA encoding a novel human protein kinase Aik which shares high amino acid identity with the Aurora/Ipl1 protein kinase family. In the present study, a second human cDNA highly homologous to aurora/IPL1 (Aik2) was identified and the nucleotide sequence was determined (gene symbol STK12). The C-terminal kinase domain of the STK12 encoded protein shares high amino acid sequence identity with those of mouse STK-1 (90%), rat AIM-1 (90%), human Aik (69%), mouse IAK1/Ayk1 (69%), Xenopus pEg2 (68%), Drosophila Aurora (62%), and yeast Ipl1 (45%), whereas the N-terminal domain of the STK12 protein shares little homology with those of Aurora/Ipl1 family members except for AIM-1 and STK-1. Northern blotting analyses revealed that STK12 expression was high in thymus, while low level expression was detected in small intestine, testis, colon, spleen, and brain. The STK12 protein content in HeLa cells is low in S phase, but it accumulates during M phase. STK12 was mapped to human chromosome 17p13.1 by fluorescence in situ hybridization. The chromosome location of STK12 was further defined using a radiation hybrid panel (Stanford G3), that showed a linkage with marker WI-7901 (LOD Score 7.83) located between D17S938 and D17S786.

Animals↗
PubMed1998

Interleukin-12 inhibits production of interleukin-5 but not of granulocyte/macrophage colony-stimulating factor by antigen-stimulated blood mononuclear cells in allergic bronchial asthmatics.

Bronchial asthma, characterized by eosinophilic inflammation in airways, may involve Th2-type cytokines such as interleukin-5 (IL-5). IL-12, a newly established cytokine, induces IFN-gamma production, which may have a regulatory effect on the production of Th2-type cytokines. We examined the effects of IL-12 on the productions of IL-5 and granulocyte/macrophage colony-stimulating factor (GM-CSF) by antigen (Dermatophagoides farinae, Df)-stimulated mononuclear cells (MNCs) from asthmatic patients in vitro. IL-12 enhanced IFN-gamma production and inhibited the production of IL-5 but not of GM-CSF by Df-stimulated MNCs from asthmatic patients. Exogenous IFN-gamma directly inhibited IL-5 production by Df-stimulated MNCs and the inhibition of IL-5 production by IL-12 was partially blocked by anti-IFN-gamma antibody in culture, indicating that inhibitory effect of IL-12 on IL-5 production by antigen-stimulated MNCs is partially dependent on IFN-gamma production. IL-12 also inhibited the release of eosinophil survival-stimulating factor from MNCs. These results indicate that IL-12 may be therapeutically beneficial in correcting Th1/Th2 imbalance in bronchial asthma.

Adult↗
PubMed1998

Protective effects of baicalein against cell damage by reactive oxygen species.

Baicalein (5,6,7-trihydroxy-2-phenyl-4H-1-benzopyran-4-one), a naturally occurring flavonoid, was found to prevent human dermal fibroblast cell damage induced by reactive oxygen species such as hydrogen peroxide (H2O2), tert-butyl hydroperoxide (BuOOH) and superoxide anions (.O2-) in a concentration-dependent manner, and was more effective than the iron chelator, deferoxamine, hydroxyl radical (.OH) scavengers such as dimethyl sulfoxide (DMSO) and ethanol (EtOH), the lipid peroxidation chain blocker, alpha-tocopherol (Vit. E) and the xanthine oxidase inhibitor, allopurinol. To probe the mechanism of cell defense, the reaction of baicalein with oxygen free radicals was investigated using electron spin resonance (ESR) spectrometry. Baicalein decreased the signal intensities due to the 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) spin adducts of .OH, .O2- and tert-butyl peroxyl (BuOO.) radicals in a concentration-dependent manner. The IC50 values, which are the 50% inhibition concentrations of baicalein for the free radicals, were 10, 45 and 310 microM, respectively. These results suggested that baicalein possesses free radical scavenging ability which prevents the fibroblast damage induced by these free radical species.

Cyclic N-Oxides↗
PubMed1998

Effect of mental stress on hemodynamics and left ventricular diastolic function in patients with ischemic heart disease.

Mental stress is an important factor affecting cardiac function. We evaluated the effect of a mental calculation stress (MS) test on hemodynamics and left ventricular (LV) diastolic function in patients with ischemic heart disease, and compared the hemodynamic responses with a treadmill exercise test. Fifteen patients were studied. Seven had old myocardial infarction with significant coronary artery stenosis (group I) and 8 had chest pain syndrome with non-significant coronary artery stenosis (group II). The MS test was performed as follows: after memorizing 6 random numeral digits, patients repeated these numbers in reverse order for 5 min followed by serial subtraction of 1000 minus 17 for 5 min. Blood pressure (BP) and heart rate (HR) were measured every 1-5 min. Doppler mitral flow velocity (MFV) was recorded every 2-5 min. During the MS test, BP, HR, and rate pressure product increased by 38.3%, 17.3%, and 62.1% on average, respectively. Early diastolic MFV decreased by 10.0% in group I and 3.3% in group 11. First third filling rate of MFV decreased by 32.3% in group I and 22.8% in group II. A/E ratio increased by 39.3% in group I and 25.8% in group II. These data indicate that the MS test led to a deterioration in LV diastolic function. The MS test induced LV diastolic dysfunction to a greater extent in patients with significant coronary artery stenosis than in those without significant coronary stenosis. Myocardial ischemia may be induced by increased left ventricular afterload and/or vasoconstrictive reflex of coronary microcirculation.

Adult↗
PubMed1998

[A clinical study of superficial bladder cancer with grade 3 components].

A retrospective study was done on 33 patients treated for superficial bladder cancer, pTa and pT1, with grade 3 components between 1986 and 1995. All patients had undergone transurethral resection of the tumor (TUR-Bt), which was followed by total cystectomy in 7 patients. Three patients died of pulmonary diseases or heart attack and 6 patients subsequently died of bladder cancer. The 2-year and 5-year disease-specific survival rates of these patients were 83% and 75%, respectively, and the mean duration of follow-up was 50 months. Comparison of the disease-specific survival rates for several factors revealed that the configuration and size of the tumors were significantly predictable factors for prognosis. In well-selected patients with grade 3 superficial bladder cancer, bladder preservation seems to be possible by TUR with or without adjuvant therapies. Hence further studies on a larger series are needed to elucidate more feasible and reliable prognostic factors to avoid unnecessary cystectomy and improve the quality of life of the patients.

Adult↗
PubMed1998

[Clinical studies on the quality of life in patients with ileal conduit].

Between August, 1985 and December. 1995 ileal conduit was performed in 36 cases of bladder cancer (30 males, 6 females). A survey based on a questionnaire was carried out on 15 patients to assess their quality of life (QOL) after the surgery. The questionnaire dealt with the working situation, appetite, sleep, defecation, bathing, travel, general health condition, satisfaction, sexual life and erection. Although only 64.0% of the patients returned to work, appetite, hours of sleep and bathing frequency showed only a slight decrease. We performed total cystectomy without using the nerve sparing method. After the operation, three patients could have an erection and enjoy sexual life. Because the ileal conduit resulted in few complications and only a slight reduction in QOL, it was considered an appropriate operation.

Activities of Daily Living↗
PubMed1998

[Effectiveness of continuous intravenous prostaglandin E 1 against pulmonary hypertension].

Pulmonary hypertension is a progressive disease for which no effective therapy has been found. Short-team treatment with alprostadil alfadex (PGE 1) can improve hemodynamics but the effects of long-term treatment have not been reported. We administered intravenous PGE 1 to 16 patients with pulmonary hypertension for 4 weeks in addition to conventional therapy. Hemodynamic and symptomatic effects were evaluated. The infusion was interrupted in 7 patients (44%) because of fever and an increase in levels of C-reactive protein in serum. In the remaining 9 patients, the drug lowered pulmonary artery pressure and resistance, and imareased cardiac output significantly in 7 patients. PGE 1 can improve hemodynamics and relieve symptoms in patients with pulmonary hypertension, barring severe side effects.

Adult↗