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T Oura

Publications and source records attributed to T Oura.

At least 19 recordsLinked to original sources
PubMed2001

Cloning of a fatty acid synthase component FAS1 gene from Saccharomyces kluyveri and its functional complementation of S. cerevisiae fas1 mutant.

A gene encoding a fatty acid synthase component, FAS1, has been cloned from a genomic library of the polyunsaturated fatty acid (PUFA)-producing yeast Saccharomyces kluyveri. This gene (named Sk-FAS1) was found to contain an open reading frame of 6150 bp, coding for 2049 amino acids. The deduced Sk-FAS1 protein showed significant (75-59%) homology with FAS proteins from the other yeasts, including S. cerevisiae, Candida albicans and Yarrowia lipolytica. The substrate-binding sites of the acetyl transferase and malonyl/palmitoyl transferase domains, and the FMN- and NADPH-binding sites of the enoyl reductase domain, were all highly conserved. Expression of the Sk-FAS1 gene in S. cerevisiae complemented genetic disruption of the S. cerevisiae FAS1 gene (Sc-FAS1), suggesting the formation of a heterogeneous complex of Sk-FAS1 (beta) and Sc-FAS2 (alpha), which is able to function to synthesize fatty acids. Compared with the isogenic wild-type of S. cerevisiae, as well as S. kluyveri, the S. cerevisiae fas1 mutant carrying the Sk-FAS1 gene showed an increase in the relative amount of 16-carbon fatty acids and a decrease in 18-carbon fatty acids.

Amino Acid Sequence↗
PubMed2000

Quantitative Beutler test for newborn mass screening of galactosemia using a fluorometric microplate reader.

BACKGROUND: The Beutler enzyme spot test is an effective assay for newborn mass screening of galactosemia, but it is qualitative and relies on visual interpretation. We describe a quantitative, instrumental modification of the assay. METHODS: We modified the macroscopic visual Beutler enzyme spot test by adding extraction of blood components from filter paper, deproteinization with acetone-methanol, and quantification and recording by a fluorescent microplate reader and personal computer. All handling was performed in microplates. The measurement time was 90 min. RESULTS: Fluorescence intensity (FI) of healthy controls correlated with hematocrit and galactose-1-phosphate uridyltransferase (GALT) activity. Patients with GALT deficiency were distinguished clearly from healthy subjects and heterozygous carriers by FI. FI decreased to 75% of the initial activity after storage at 25 degrees C for 3 days and to 40% after storage at 37 degrees C for 7 days. Screening of 46 742 newborns yielded 1 false-positive result (in a heterozygous carrier), 1 patient with glucose-6-phosphate dehydrogenase deficiency, and no apparent false negatives as judged by concurrent measurements of galactose and galactose-1-phosphate. CONCLUSIONS: The quantitative Beutler test can provide precise GALT activity in newborn mass screening, and can take into consideration the influence of high temperature and humidity, duration between sampling and testing, and anemia. This method is clinically useful, simple, automated, and highly reliable for newborn mass screening of galactosemia.

Blood Specimen Collection↗
PubMed1999

Life-long treatment for phenylketonuria.

Life-long low-phenylalanine diet is recommended as an additional determinant to achieve the maximal success in the treatment of phenylketonuria (PKU). In this context education of teenage patients with PKU is essential.

Adolescent↗
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

Evaluation of highly sensitive thyrotropin assay for detecting thyroid diseases in neonatal screening: preliminary studies.

TSH concentrations in dried blood samples on filter paper were determined by a conventional enzyme-linked immunosorbent assay (ELISA), used for routine neonatal screening for primary hypothyroidism, and a highly sensitive bioluminescence ELISA (BL-ELISA) using firefly luciferase to examine whether central hypothyroidism and hyperthyroidism can be efficiently detected as cases of primary hypothyroidism. Samples were obtained from 3 patients with congenital central hypothyroidism, 5 patients with congenital primary hypothyroidism, 6 patients with hyperthyroidism, 31 neonatal babies with low birth weight (premature babies) and 242 newborn babies with normal birth weight from the general population (normal babies). The TSH values were low in central hypothyroidism and hyperthyroidism. Their deviations from the mean TSH value for normal babies by the BL-ELISA method (-3.12 SD and -4.79 SD in central hypothyroidism and hyperthyroidism respectively) were greater than those by the ELISA method (-2.00 SD and -2.97 SD respectively). The TSH values were high in primary hypothyroidism and normal in premature babies while deviations were the same when BL-ELISA and ELISA were used. These findings indicate that the highly sensitive TSH assay (BL-ELISA) can be used for detecting both primary and central hypothyroidism as well as hyperthyroidism in neonatal screening.

Adult↗
PubMed1997

Single amino acid residue as a functional determinant of rod and cone visual pigments.

The visual transduction processes in rod and cone photoreceptor cells begin with photon absorption by the different types of visual pigments. Cone visual pigments exhibit faster regeneration from 11-cis-retinal and opsin and faster decay of physiologically active intermediate (meta II) than does the rod visual pigment, rhodopsin, as expected, due to the functional difference between rod and cone photoreceptor cells. To identify the amino acid residue(s) responsible for the difference in molecular properties between rod and cone visual pigments, we selected three amino acid positions (64, 122, and 150), where cone visual pigments have amino acid residues electrically different from those of rhodopsin, and prepared mutants of rhodopsin and chicken green-sensitive cone visual pigment. The results showed that the replacement of Glu-122 of rhodopsin by the residue containing green- or red-sensitive cone pigment converted rhodopsin's rates of regeneration and meta II decay into those of the respective cone pigments, whereas the introduction of Glu-122 into green-sensitive cone visual pigment changed the rates of these processes into rates similar to those of rhodopsin. Furthermore, exchange of the residue at position 122 between rhodopsin and chicken green-sensitive cone pigment interchanges their efficiencies in activating retinal G protein transducin. Thus, the amino acid residue at position 122 is a functional determinant of rod and cone visual pigments.

Animals↗
PubMed1997

Low diastolic blood pressure, hypoalbuminemia, and risk of death in a cohort of chronic hemodialysis patients.

In a previous report, we showed that nutritional status and especially serum albumin had great predictive value for death in chronic hemodialysis patients, whereas blood pressure did not. In the present study, we analyzed the causes of death in consideration of the relationship between serum albumin and blood pressure. A total of 1,243 Okinawan patients (719 males, 524 females) undergoing hemodialysis in January 1991 were followed up through the end of 1995. Three hundred forty-two of the patients died, 45 received transplants, and 12 were transferred by the end of the follow-up period. The total duration of observation was 5,110.3 patient-years. Blood pressure as well as clinical and laboratory variables were determined immediately prior to the first dialysis session in January 1991. The crude death rate was 40.0% when the diastolic blood pressure (DBP) <70 mm Hg, 35.0% at 70 to 79 mm Hg, 25.0% at 80 to 89 mm Hg, 25.0% at 90 to 99 mm Hg, and 13.0% at >100 mm Hg. The death rate showed an inverse correlation with DBP. DBP showed a significant positive correlation with serum albumin (r = 0.137, P < 0.001) and age (r = -0.325, P < 0.0001). The adjusted odds ratio (95% confidence interval) of death was 0.84 (0.71 to 0.99) with 10 mm Hg increments in DBP when the reference DBP was less than 69 mm Hg. Low DBP may be a manifestation of malnutrition and/or cardiovascular disease in chronic hemodialysis patients. Target DBP levels may be higher levels in chronic hemodialysis patients than the general population.

Blood Pressure↗
PubMed1996

Molecular properties of chimerical mutants of gecko blue and bovine rhodopsin.

In spite of the high similarity in amino acid sequence between rod visual pigment rhodopsin and gecko blue-sensitive pigment (gecko blue), not only the spectral sensitivities but also the thermal decay rates of the meta II- and III-intermediates are noticeably different from one another [Kojima et al. (1995) Biochemistry 34, 1096-1106]. In order to identify the protein region(s) that contain(s) key residue being responsible for the functional difference, we constructed six chimerical mutants derived from gecko blue and bovine rhodopsin, with the aid of protein production in a human embryonic kidney cell line (293S). While the absorption maximum of every mutant was located in between gecko blue (466 nm) and bovine rhodopsin (500 nm), a large blue-shift (18 nm) was observed when the helices I-III of rhodopsin were replaced with those of gecko blue. A time resolved spectroscopic study demonstrated that this replacement also accelerated the decay rate of the meta II-intermediate. The decay of the meta III-intermediate of the mutants became faster as the compartment of gecko blue was increased. Thus, the faster decay of the meta II-intermediate of gecko blue is largely attributed to residues within helices I-III, while the decay of the meta III-intermediate apparently depends on the overall structure of the protein.

Animals↗
PubMed1994

An epidemiologic analysis of end-stage lupus nephritis.

We analyzed 566 patients (515 females and 51 males) with systemic lupus erythematosus who were treated in Okinawa, Japan, from 1972 to 1991 and followed until April 1993. One hundred four patients (95 females and 9 males) died, and 51 were considered to have end-stage lupus nephritis. The annual incidence and prevalence, per million population in each sex, were increased from 16.0 and 66.0 in 1972 to 46.7 and 683.9 in 1991 in the female patients, and from 4.2 and 8.3 in 1973 to 8.3 and 70.0 in 1991 in the male patients, respectively. Cox proportional hazard analysis was done to determine the effects of several covariates on patients and renal survival. The patients' survival rate improved, as the hazard ratio (HR) was decreased to 0.69 (year of diagnosis, 1982 to 1986) and to 0.48 (year of diagnosis, 1987 to 1991) when the HR in patients diagnosed before 1981 was taken as 1.00. Similarly, we examined renal survival by using the Cox proportional model. For this analysis, the date of start of dialysis therapy was regarded as the time of renal death. Male patients had significantly poor renal survival; the HR was 3.64 (95% confidence interval, 1.89 to 6.98) when the HR in the females was taken as 1.00. However, age at diagnosis and year of diagnosis did not significantly affect renal survival. The cumulated incidence of end-stage lupus nephritis from the time of diagnosis of systemic lupus erythematosus was 3.1% at 5 years, 9.4% at 10 years, 15.5% at 15 years, and 21.0% at 20 years.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Fetal liver biopsy for prenatal diagnosis of carbamoyl phosphate synthetase deficiency.

Carbamoyl phosphate synthetase deficiency is a type of an inborn error of metabolism with a poor prognosis. Carbamoyl phosphate synthetase is a liver-specific enzyme, and its deficiency can only be diagnosed by enzyme assay using liver biopsy specimens. A pregnant woman at risk for carbamoyl phosphate synthetase deficiency was evaluated for the purpose of prenatal diagnosis of the condition. Fetal liver biopsy was performed at the 22nd week of gestation. The results of enzyme assays on fetal liver biopsy revealed normal enzymatic activity and the diagnosis of carbamoyl phosphate synthetase deficiency was ruled out prenatally. Methods and safety of fetal liver biopsy are discussed. Measurements of activity of liver-specific enzymes were evaluated with respect to methodology and manner of assessment. Prenatal diagnosis of deficiencies in liver-specific enzymes, which have hitherto been considered difficult to detect before birth, has now become possible.

Adult↗
PubMed1992

Frequency and distribution of phenylketonuric mutations in Orientals.

The frequency and distribution of eight mutations (R111X, IVS4nt-1, Y204C, R243Q, IVS7nt-2, W326X, Y356X, and R413P) in the phenylalanine hydroxylase gene of Orientals in Japan and Korea were examined by allele-specific oligonucleotide hybridization. The mutant alleles comprised 54 and 55% of the phenylketonuria (PKU) chromosomes examined in 36 patients in Japan and 10 patients in Korea, respectively. The spectrum of PKU mutations in Japan was similar to that in China, particularly in northern China, but different from that in Korea. The IVS4nt-1 mutation had a high frequency in Korea and southern China, due to the result of the founder effect and genetic drift. The R413P mutation, which may have originated in the regions surrounding the Baikal, expanded to northern China and Japan. We did not find Caucasian mutations in the Japanese or Korean PKU chromosomes. Thus, PKU mutations occurred after racial divergence between Caucasians and Mongoloids, and there were different founding populations for PKU in the two populations.

Alleles↗