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Biomedical subjects

Y Tani

Publications and source records attributed to Y Tani.

At least 73 records · Page 4Linked to original sources
PubMed2000

Characterization of a flavinogenic mutant of methanol yeast Candida boidinii and its extracellular secretion of riboflavin.

A flavinogenic mutant was derived from Candida boidinii by mutagenesis. The mutant was smaller than the wild type, did not grow on a minimal medium, and required l-tryptophan, l-leucine, inositol, and nicotinate for growth. The mutant was defective in the oxidative pentose phosphate pathway, lacking glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. The specific activities of the transaldolase and transketolase of the mutant were higher than those of the wild type. These high activities might direct the flux of the carbon source to the nonoxidative pathway with formation of a large amount of pentose phosphates, increasing riboflavin synthesis. Under microaerobic conditions at 25 degrees C, 90 mg/l riboflavin was obtained.

Journal Article↗
PubMed1999

Regulation of intestinal Na+-dependent phosphate co-transporters by a low-phosphate diet and 1,25-dihydroxyvitamin D3.

In a study of the rat intestinal P(i) transport system, an activator protein for rat Na/P(i) co-transport system (PiUS) was isolated and characterized. We also investigated the effects of restriction of vitamin D and P(i) (two of the most important physiological and pathophysiological regulators of P(i) absorption in the small intestine) on intestinal P(i) transport activity and the expression of Na/P(i) co-transporters that are expressed in rat small intestine. Rat PiUS encodes a 424-residue protein with a calculated molecular mass of 51463 Da. The microinjection of rat PiUS into Xenopus oocytes markedly stimulated Na(+)-dependent P(i) co-transport activity. In rats fed with a low-P(i) diet, Na(+)-dependent P(i) co-transport activity was increased approx. 2-fold compared with that of rats fed a normal P(i) diet. Kinetic studies demonstrated that this increased activity was due to an elevation of V(max) but not K(m). The PiUS mRNA levels showed an approximate doubling in the rats fed with the low-P(i) diet compared with those fed with the normal P(i) diet. In addition, after the administration of 1, 25-dihydroxyvitamin D(3) [1,25-(OH)(2)D(3)] to vitamin D-deficient animals, the P(i) uptake was significantly increased in the Na(+)-dependent component in the brush border membrane vesicle (BBMV) at 24 and 48 h. In addition, we found a further high-affinity Na/P(i) co-transport system in the BBMV isolated from the vitamin D-replete animals. The levels of type III Na/P(i) co-transporter PiT-2 mRNA were increased 24 and 48 h after 1,25-(OH)(2)D(3) administration to vitamin D-deficient animals, whereas PiUS and the type IIb Na/P(i) co-transporter mRNA levels were unchanged. In conclusion, we first cloned a rat activator protein, PiUS, and then studied its role along with that of other type III Na/P(i) co-transporters. PiUS and PiT-2 might be important components in the regulation of the intestinal P(i) transport system by P(i) restriction and 1,25-(OH)(2)D(3).

Amino Acid Sequence↗
PubMed1999

Hepatic cytochrome P450 and flavin-containing monooxygenase in male Nts:Mini rat, a transgenic rat carrying antisense RNA transgene for rat growth hormone.

We investigated the characteristics of hepatic cytochrome P450s and flavin-containing monooxygenase 1 (FMO1) in male Nts:Mini rats, a Wistar/Jcl-derived transgenic rat strain showing less plasma GH concentration than the parental strain. The total hepatic P450 contents of Mini rats were significantly reduced. A suppression was observed in the activities and protein expression of male-specific P450s (CYP3A and CYP2C11) and was speculated to be a potential cause of the reduction in total P450 contents. The activity and protein expression of CYP2B1 were suppressed and those of CYP2E1 and CYP2B2 were enhanced. With the exception of our data on CYP2B1, these results largely agreed with previous reports concerning GH-depletion rat models (hypophysectomized rats, rats neonatally treated with glutamate, and dwarf rats), implying that the changes in Mini rats were caused by GH insufficiency. The liver FMO1 protein expression in Mini rats was higher than that in Wistar rats but the activity was comparable, suggesting that GH is not a positive regulator of FMO expression. With their insufficient but not depleted levels of plasma GH, Mini rats may thus become another candidate for use in the investigation of GH regulation of hepatic mixed-function monooxygenases.

Animals↗
PubMed1999

A novel frameshift mutation in the McLeod syndrome gene in a Japanese family.

We report a novel mutation in the XK gene (XK) in a Japanese patient with McLeod syndrome. A 50-year-old man showed progressive muscular atrophy, choreic movement, elevated level of serum creatinine kinase, and acanthocytosis. The expression level of all the Kell antigens in erythrocyte was decreased and molecular analysis revealed a single-base (T) deletion at the nucleotide position 1095 in XK. This deletion caused a frameshift in translation, leading to a premature stop codon at the amino acid position 408. We conclude this single-base deletion causes defective Kx protein, which is responsible for the McLeod phenotype in this patient.

Amino Acid Transport Systems, Neutral↗
PubMed1999

The genomic organization of the partial D category DVa: the presence of a new partial D associated with the DVa phenotype.

Within the Rh blood group, the partial D phenotype is a well known RhD variant, that induces Rh-incompatible blood transfusion and hemolytic diseases in the newborn. The partial D category DVa phenotype (DVa Kou.) results from a hybrid of RhD-CE-D transcript. We demonstrated a genomic organization of the hybrid RHD-CE-D gene leading to the DVa phenotype, and showed that the DVa gene were generated from gene conversion between the RHD and the RHCE genes in relatively small regions. This study also revealed that the presence of a new partial D associated with the DVa phenotype, which we termed the DVa-like phenotype. In this phenotype, five RHD-specific nucleotides were replaced with the corresponding RHCE-derived nucleotides on the exon 5 of the RHD gene. In addition, two variants of the mutated RHD genes at nucleotide 697 were revealed in the RhD variant samples. These results will provide useful information for future research into the diversification of the Rh polypeptides.

Alleles↗
PubMed1999

Characterization of a biosurfactant, mannosylerythritol lipid produced from Candida sp. SY16.

One yeast strain, SY16, was selected as a potential producer of a biosurfactant, and identified as a Candida species. A biosurfactant produced from Candida sp. SY16 was purified and confirmed to be a glycolipid. This glycolipid-type biosurfactant lowered the surface tension of water to 29 dyne/cm at critical micelle concentration of 10 mg/l (1.5 x 10(-5) M), and the minimum interfacial tension was 0.1 dyne/cm against kerosene. Thin-layer and high-pressure liquid chromatography studies demonstrated that the glycolipid contained mannosylerythritol as a hydrophilic moiety. The hydrophilic sugar moiety of the biosurfactant was determined to be beta-D-mannopyranosyl-(1-->4)-O-meso-erythritol by nuclear magnetic resonance (NMR) and fast atom bombardment mass-spectroscopy analyses. The hydrophobic moiety, fatty acids, of the biosurfactant was determined to be hexanoic, dodecanoic, tetradecanoic, and tetradecenoic acid by gas chromatography-mass spectroscopy. The structure of the native biosurfactant was determined to be 6-O-acetyl-2,3-di-O-alkanoyl-beta-D-mannopyranosyl-(1-->4)-O-meso- erythritol by NMR analyses. We newly determined that an acetyl group was linked to the C-6 position of the D-mannose unit in the hydrophilic sugar moiety.

Candida↗
PubMed1999

Locking of metacarpophalangeal joints in a patient with acromegaly.

A 39-year-old man with acromegaly exhibited locking of metacarpophalangeal (MCP) joints of both index fingers. Large osteophytes were found at the metacarpal heads by radiography and computerized tomography (CT). Magnetic resonance (MR) images revealed hypertrophy of volar plates. We suggest that these characteristic acromegalic features caused locking of MCP joints. Surgery was required on one of the joints to release the locking.

Acromegaly↗
PubMed1999

Sociodemographic factors and failure of hip arthroplasty.

To identify the sociodemographic and lifestyle factors related to development of aseptic loosening after a cemented total hip arthroplasty (THA), 151 consecutive primary THAs performed at a single hospital in a rural district of Japan, at a mean follow-up of 7.5 years, were reviewed. Based on the medical records collected during hospital admission for THA, in which sociodemographic and lifestyle backgrounds had been recorded by the nurse, answers regarding residence, education, employment, engagement in agricultural work, marital status, family members living together, religion, recreational activity, smoking, and alcohol intake were analyzed in relation to the development of loosening, using a multivariate Cox proportional hazards model. With adjustment for cementing technique, diagnosis, age, and sex, agricultural work had a significant relation with prosthetic loosening (relative risk=2.85, P=0.03). Restriction of physical work in agriculture for patients undergoing THA should be considered.

Adult↗
PubMed1999

The STR polymorphisms in intron 8 may provide information about the molecular evolution of RH haplotypes.

We identified simple-sequence repeat polymorphisms in intron 8 of the RHD and RHCE genes, both of which contained the 5-bp repeat unit (AAAAT)n. We analyzed the polymorphisms of this short tandem repeat (STR) in 104 Japanese RhD-positive and 124 RhD-negative (87 RHD gene negative and 37 nonfunctional RHD gene positive) donors by the polymerase chain reaction (PCR) and subsequent typing by electrophoresis and silver staining. We found five alleles (10, 11, 12, 13, and 14 repeats) in the RHD gene and four (7, 8, 9, and 10 repeats) in the RHCE gene. The Rh phenotypes were closely associated with polymorphisms of the STR. The Ce allele had 12 repeats in the RHD gene and 9 repeats in the RHCE gene at high frequency. The cE allele frequently had 10-12 repeats in the RHD gene and 10 repeats in the RHCE gene. The 10 repeats in the RHCE gene were identified exclusively in the 87 RHD gene-negative donors and 9 repeats were identified only in those with the RhC antigen. These results indicate that both haplotypes of dce and dcE arose from single RHD gene deletion and recombination events, respectively. In the 37 RhD-negative donors with a nonfunctional RHD gene, 12 repeats in the RHD gene and 9 repeats in the RHCE gene were frequently observed. Thus, the RhD-negative with a nonfunctional RHD gene combination might have arisen from the DCe haplotype via a mutation that abolished RHD gene expression. These findings suggest that the STR polymorphisms might shed light upon the molecular evolution of RH haplotypes.

Alleles↗
PubMed1999

Comparative study of intramuscular and intraskeletal osteogenesis by recombinant human bone morphogenetic protein-2.

OBJECTIVE: The purpose of this study was to compare the osteoinducing activity of recombinant human bone morphogenetic protein-2 (rhBMP-2) at intramuscular and intraskeletal sites in rats. STUDY DESIGN: Five tg of rhBMP-2 was implanted into the right calf muscle of each of 20 rats and into a hole (4 mm in diameter, 1.5 mm in depth) that was made in the mandibular body of each of 20 other rats, with atelopeptide type I collagen as a carrier. The alkaline phosphatase activity and calcium content were quantitatively analyzed 1, 3, 7, and 21 days after the implantation of rhBMP-2 into either mandibular bone (in the intraskeletal group) or calf muscle (in the intramuscular group). The new bone formation was evaluated histologically 21 days after implantation. RESULTS: On days 1 and 3, the alkaline phosphatase activity and calcium content in the intraskeletal group showed no significant differences from those in the intramuscular group. On the 7th and 21st days after implantation, however, the alkaline phosphatase activity and calcium content in the intraskeletal group were significantly higher than those in the intramuscular group. Histometry of the microscopic views showed that the mean trabecular area was 0.87 mm2 in the intramuscular group and 2.66 mm2 in the intraskeletal group. CONCLUSIONS: These results suggest that the new bone formation stimulated by rhBMP-2 in the intraskeletal group was greater than in the intramuscular group.

Alkaline Phosphatase↗
PubMed1999

Purification and characterization of an enzyme that has dihydroxyacetone-reducing activity from methanol-grown Hansenula ofunaensis.

An intracellular enzyme having reduction activity towards dihydroxyacetone (DHA), and that was induced by DHA, was purified and characterized from a methanol-grown yeast, Hansenula ofunaensis. After harvesting cells grown in a 1% methanol medium until the early stationary phase, the enzyme was purified through ammonium sulfate fractination and a series of ion-exchange, hydrophobic, and gel-filtration column chromatographies. SDS-PAGE and HPLC showed the enzyme to be a homo dimer composed of two identical subunits, each with a molecular mass of 38 kDa. The optimum pHs for DHA reduction and glycerol oxidation were 6.0 and 7.0, respectively. The optimum temperature for enzyme activity was 55 degrees C. The enzyme reduced several other compounds, including acetaldehyde, acetol, 2-butanone and 3-methyl-2-butanone, more effectively than it did DHA, while its oxidation activity was higher towards ethanol, 2-propanol, 1,2-propanediol, 2,3-butanediol and 1,3-butanediol than towards glycerol. The K(m) values for DHA in reduction and glycerol in oxidation were 430 mM and 4 M, respectively. The K(m) values for DHA in reduction and glycerol in oxidation were 430 mM and 4 M, respectively. The purified enzyme had high K(m) values for glycerol and DHA and low K(m) values for 2-butanol and butanone, although physiologically it had a role in DHA metabolism. There were similarities between the purified enzyme and sec-alcohol dehydrogenases reported previously in their behavior towards inhibitors and metal ions, as well as in their K(m) values for 2-butanol and 2-butanone, but differences in their subunit molecular masses and activities for ethanol. At pH 9.8, the oxidative activity of the purified enzyme for l-2-butanol was about eleven times higher than that for d-2-butanol.

Journal Article↗
PubMed1999

Comparison of recombinant and purified human bone morphogenetic protein.

Clinically, it would be more convenient to use recombinant than purified preparations of bone morphogenetic protein (BMP). Recently, recombinant human BMP (rhBMP) has attracted the attention of many investigators, but it has not been fully characterized. We examined the bone-inducing activity of rhBMP-2 and compared it with that of purified BMP derived from human bone matrix (phBMP). Two, 10, or 50 microg of rhBMP-2 or phBMP was mixed with 3 mg of atelopeptide type I collagen (carrier), and specimens were implanted in the calf muscles of Wistar rats (n=5 in each group). Four weeks later, new bone had formed in all the rhBMP-2- and phBMP-implanted muscles and was visible radiographically and histologically. The quantitative analysis indicated that the activity of rhBMP-2 was less than one tenth that of phBMP. It is necessary to find out why rhBMP-2 has fewer activities than phBMP.

Alkaline Phosphatase↗
PubMed1999

Analysis of receptor for Vibrio cholerae El tor hemolysin with a monoclonal antibody that recognizes glycophorin B of human erythrocyte membrane.

El Tor hemolysin (ETH), a pore-forming toxin secreted by Vibrio cholerae O1 biotype El Tor and most Vibrio cholerae non-O1 isolates, is able to lyse erythrocytes and other mammalian cells. To study the receptor for this toxin or the related molecule(s) on erythrocyte, we first isolated a monoclonal antibody, B1, against human erythrocyte membrane, which not only blocks the binding of ETH to human erythrocyte but also inhibits the hemolytic activity of ETH. Biochemical characterization and immunoblotting revealed that this antibody recognized an epitope on the extracellular domain of glycophorin B, a sialoglycoprotein of erythrocyte membrane. Erythrocytes lacking glycophorin B but not glycophorin A were less sensitive to the toxin than were normal human erythrocytes. These results indicate that glycophorin B is a receptor for ETH or at least an associated molecule of the receptor for ETH on human erythrocytes.

Antibodies, Monoclonal↗
PubMed1999

[Intra-arterial chemotherapy for invasive bladder cancer].

The present investigation was conducted to examine the effects of intra-arterial chemotherapy (IAC) for patients with invasive bladder cancer. A total of 37 patients were treated with IAC at Nara Medical University and its affiliated hospitals between January, 1993 and August, 1997. There were 27 patients in the poor risk group. The remaining 10 patients underwent anti-tumor IAC. Thirty of the 37 patients received chemotherapeutic agents via a reservoir, and the remaining 7 patients received a one-shot injection of agents followed by transcatheter arterial embolization (TAE). In the reservoir group, there were 18 patients who received IAC in combination with radiation therapy. As a result, reduction of tumor size was noted in 53%, and the 3-year cause-specific survival rate was 54% in all cases. There was a significant difference in the 3-year survival rate between the radiation-treated group and the group without radiation. The adverse events included anemia, leukopenia, thrombocytopenia and gastrointestinal symptoms, but none of them were severe. The results of the present study indicate that IAC is useful in the treatment of invasive bladder cancer for poor risk patients.

Aged↗
PubMed1999

Production of secretory component and pathogenesis of gastric cancer in Helicobacter pylori-infected stomach.

The purpose of this study was to examine the production of secretory component (SC) and immunoglobulin A (IgA) in the gastric mucosa with Helicobacter pylori infection and to investigate the influence of immunological reactions on various phases of infection (gastritis, intestinal metaplasia, gastric cancer). Production of SC and IgA was assessed by immunohistochemical staining in (1) endoscopic biopsy samples of H. pylori-eradicated cases (n = 25), and (2) surgically resected stomach tissues of H. pylori-positive gastric cancer cases, intestinal type (IGC, n = 25) and diffuse type (DGC, n = 25). Before eradication therapy, all samples showed positive staining of SC and IgA in epithelial cells, and IgA was also positive in plasma cells in the mucosal layer. H. pylori bacteria were positively stained for SC and IgA. After treatment, the degree of SC and IgA staining in epithelial cells was reduced with successful eradication; but with intestinal metaplasia, SC staining was positive regardless of the results of treatment. In nonmetaplastic mucosa, SC-positive cells were increased in the glandular neck zone to the surface mucosal layer; and the intensity of SC staining was increased in proportion to the degree of mucosal inflammation and IgA-positive cell aggregation. In intestinal metaplasia, SC was positive irrespective of the degree of inflammation. Most cancer foci also showed positive staining of SC, irrespective of histological type. Production of SC and IgA was thought to be a specific reaction against H. pylori infection, occurring from the early to the late stages and not limited to intestinal metaplasia. It was suggested that immunological reactions against H. pylori infection might generally be involved with the pathogenesis of intestinal metaplasia and both histological types of gastric cancer (IGC and DGC).

Gastric Mucosa↗
PubMed1998

Identification of three isoforms for the Na+-dependent phosphate cotransporter (NaPi-2) in rat kidney.

We have isolated three unique NaPi-2-related protein cDNAs (NaPi-2alpha, NaPi-2beta, and NaPi-2gamma) from a rat kidney library. NaPi-2alpha cDNA encodes 337 amino acids which have high homology to the N-terminal half of NaPi-2 containing 3 transmembrane domains. NaPi-2beta encodes 327 amino acids which are identical to the N-terminal region of NaPi-2 containing 4 transmembrane domains, whereas the 146 amino acids in the C-terminal region are completely different. In contrast, NaPi-2gamma encodes 268 amino acids which are identical to the C-terminal half of NaPi-2. An analysis of phage and cosmid clones indicated that the three related proteins were produced by alternative splicing in the NaPi-2 gene. In a rabbit reticulocyte lysate system, NaPi-2 alpha, beta, and gamma were found to be 36, 36, and 29 kDa amino acid polypeptides, respectively. NaPi-2alpha and NaPi-2gamma were glycosylated and revealed to be 45- and 35-kDa proteins, respectively. In isolated brush-border membrane vesicles, an N-terminal antibody was reacted with 45- and 40-kDa, and a C-terminal antibody was reacted with 37-kDa protein. The sizes of these proteins corresponded to those in glycosylated forms. A functional analysis demonstrated that NaPi-2gamma and -2alpha markedly inhibited NaPi-2 activity in Xenopus oocytes. The results suggest that these short isoforms may function as a dominant negative inhibitor of the full-length transporter.

Amino Acid Sequence↗