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Biomedical subjects

H Okuda

Publications and source records attributed to H Okuda.

At least 55 records · Page 3Linked to original sources
PubMed2000

Cloning and characterization of erythroid-specific DNase I-hypersensitive site in human rhesus-associated glycoprotein gene.

Rhesus-associated glycoprotein is a critical co-factor in the expression of rhesus blood group antigens. We identified and cloned an erythroid-specific major DNase I-hypersensitive site located about 10 kilobases upstream from the translation start site of the RHAG gene. A short core enhancer sequence of 195 base pairs that corresponded with the major hypersensitive site and possessed position- and orientation-independent enhancer activity in K562 cells. In vitro DNase I footprint analysis revealed four protected regions in the core enhancer; two GATA motifs, an Ets-like motif and an unknown motif. The GATA motifs bound GATA-1 and mutagenesis analysis revealed that the proximal one is critical for the enhancing activity. Homology plot analysis using the 5' sequence of the mouse RHAG gene revealed four homologous stretches and multiple insertions of repetitive sequences among them; four LINE/L1 and four Alu in the human and as well as one LINE/L1 and one LTR/MaLR in the mouse gene. The highly conservative enhancer region was flanked by SINE and LINE/L1 in both species. These results suggest that the 5'-flanking sequence of RHAG gene is a preferable target sequence for retroviral transposition and that the enhancer was inserted in the same manner, resulting in the acquisition of erythroid dominant expression.

Animals↗
PubMed2000

Substrate-dependent lipolysis induced by isoproterenol.

The relationship between isoproterenol-induced lipolysis and the phosphorylation of perilipin and hormone-sensitive lipase (HSL) was examined using cell-free systems consisting of lipid droplets isolated from rat fat cells and HSL, and/or trioleoylglycerol emulsified with gum arabic and HSL. Isoproterenol was found to stimulate lipolysis in the cell-free system with the lipid droplets without an increase in the phosphorylation of either perilipin or HSL. On the other hand, no stimulation of lipolysis was found in the cell-free system containing lipid droplets despite increases in the phosphorylation of perilipin and HSL. In the cell-free system consisting of trioleoylglycerol emulsified with gum arabic and HSL, neither isoproterenol nor increases in the phosphorylation of perilipin and HSL accelerated lipolysis. These results suggest that isoproterenol-induced lipolysis may not be mediated through the phosphorylation of perilipin and HSL, and may rather be dependent on the substrate of HSL.

Adrenergic beta-Agonists↗
PubMed2000

The analysis of nucleotide substitutions, gaps, and recombination events between RHD and RHCE genes through complete sequencing.

We determined the entire nucleotide sequences of all introns within the RHD and RHCE genes by amplifying genomic DNA using long PCR methods. The RHD and RHCE genes were 57,295 and 57,831 bp in length, respectively. Aligning both genes revealed 138 gaps (insertions and deletions) below 100 bp, 1116 substitutions in all introns and all exons (coding region), and 5 gaps of over 100 bp. Homologies (%) between the RH genes were 93.8% over all introns and coding exons and 91.7% over all exons and introns. Various short tandem repeats (STRs) and many interspersed nuclear elements were identified in both genes. The proportions of Alu sequences in the RHD and RHCE genes were 25.9 and 25.7%, respectively and these Alu sequences were concentrated in several regions. We confirmed multiple recombinations in introns 1 and 2. Such multiple recombination, which probably arose due to the concentrations of Alu sequences and the high level of the homology (%), is one of most important factors in the formation and evolution of RH gene. The variability of the Rh system may be generated because of these features of RH genes. Apparent mutational hotspots and regions with low of K values (the numbers of substitutions per nucleotide site) caused by recombinations as well as true mutational hotspots may be found in human genome. Accordingly, in searching for and identifying single nucleotide polymorphisms (SNPs) especially in noncoding regions, apparent mutational hotspots and areas of low K values by recombination should be noted since the unequal distribution of SNPs will reduce the power of SNPs as genetic maker. Combining the complete sequences' data of both RH genes with serological findings will provide beneficial information with which to elucidate the mechanism of recombination, mutation, polymorphism, and evolution of other genes containing the RH gene as well as to analyze Rh variants and develop new methods of Rh genotyping.

Base Sequence↗
PubMed2000

Serum levels of des-gamma-carboxy prothrombin measured using the revised enzyme immunoassay kit with increased sensitivity in relation to clinicopathologic features of solitary hepatocellular carcinoma.

BACKGROUND: Des-gamma-carboxy prothrombin (DCP) is an established marker for hepatocellular carcinoma (HCC), but the conventional enzyme immunoassay (EIA) kit lacks adequate sensitivity. Thus, a revised EIA kit with increased sensitivity has been developed. In this kit, the sensitivity has increased while high specificity to HCC has been maintained. The authors have already reported the clinical usefulness of this revised EIA kit. In this study, they examined the serum levels of DCP measured by this revised EIA kit in relation to the clinicopathologic features of solitary HCC. METHODS: Fifty-six patients with solitary HCC who underwent hepatectomy were studied. The relation between the greatest dimension and the histologic differentiation of HCC was investigated in these 56 patients, as were the serum levels of DCP measured by the revised EIA kit (Sensitive DCP), alpha-fetoprotein (AFP), and DCP measured by the conventional EIA kit (DCP). The cutoff value for Sensitive DCP was set at 40 mAU/mL, and the values for AFP and DCP were 20 ng/mL and 100 mAU/mL (0.1 AU/mL), respectively. RESULTS: The positivity rates for Sensitive DCP, AFP, and DCP (n = 56) were 53.6%, 53.6%, and 35.7%, respectively, and the rate was 73.2% when Sensitive DCP was used in combination with AFP (Sensitive DCP + AFP). The positivity rates for these markers were as follows: 1) When the greatest dimension of HCC was more than 3 cm (n = 16) and less than 2 cm (n = 23), the rates were 81.3% and 30.4% for Sensitive DCP, 68. 8% and 39.1% for AFP, 56.3% and 13.0% for DCP, and 93.8% and 56.5% for Sensitive DCP + AFP. 2) When HCC was moderately to poorly differentiated (n = 41) and well differentiated (n = 15), the rates were 68.3% and 13.3% for Sensitive DCP, 61.0% and 33.3% for AFP, 48. 8% and 0% for DCP, and 85.4% and 40% for Sensitive DCP + AFP. 3) When HCC was either more than 3 cm or moderately to poorly differentiated (n = 42) and either less than 2 cm or well differentiated (n = 27), the rates were 69.0% and 29.6% for Sensitive DCP, 61.9% and 37.0% for AFP, 47.6% and 11.1% for DCP, and 85.7% and 51.9% for Sensitive DCP + AFP. CONCLUSIONS: DCP measured by the revised EIA kit with increased sensitivity has a stronger correlation than AFP with size and histologic differentiation of HCC. This Sensitive DCP is a very useful marker for HCC and should be used in combination with AFP.

Adult↗
PubMed2000

A Japanese propositus with D-- phenotype characterized by the deletion of both the RHCE gene and D1S80 locus situated in chromosome 1p and the existence of a new CE-D-CE hybrid gene.

In a family study of a Japanese propositus with the D-- phenotype, the serological data of her D-- phenotype and those of her parents were discrepant. Gene analysis of the propositus showed a gross deletion of the RHCE gene and a new rearrangement of RHCE to yield the CE-D-CE hybrid. It was demonstrated that the hybrid CE-D-CE gene consisted of exon 1 from the RHCE gene, followed by exons 3 to 7 from the RHD gene and exons 8 to 10 from the RHCE gene. However, whether or not exon 2 of the RHD or the RHCE gene was contained in the CE-D-CE gene remained unclear. Moreover, spacer analysis between both RH genes and the family study suggested that the D-- gene complex from the paternal and maternal sides consisted of only the CE-D-CE hybrid gene and a single RHD gene, respectively. For the purpose of confirming the parent-child relationship, a paternity test using DNA fingerprint and polymerase chain reaction (PCR) analysis at the D1S80 locus were performed. DNA fingerprints with two kinds of DNA minisatellite probes (33.15 and 33.6) confirmed that the parent-child relationship in the D-- propositus was compatible. However, in the present case, at the D1S80 locus, the PCR product derived from the mother was lacking, thereby negating a parent-child relationship. It is probable that the RH genes and D1S80 locus exist in close proximity, because they are situated in chromosomes 1p 34.3-36.1 and 1p 36.1-36.3, respectively. These data suggested that at the stage of gametogenesis, both the RHCE gene and the D1S80 locus from the maternal side may have been deleted, thereby producing the D-- gene complex.

Chimera↗
PubMed2000

Inhibitory effects of chondroitin sulfate prepared from salmon nasal cartilage on fat storage in mice fed a high-fat diet.

OBJECTIVE: Chondroitin sulfate is an acidic polymer consisting of repeating D-glucuronic acid and D-N-acetylgalactosamine units, and the N-acetylgalactosamine is substituted with the sulfate at either the 4' or 6' position, with approximately one sulfate being present per disaccharide unit. The present study assessed the effects of chondroitin sulfate on the activity of pancreatic lipase and lipid uptake into brush border membrane vesicles of the rat small intestine in vitro, and on the degree of fat storage induced in mice by the oral administration of a high-fat diet for 8 weeks. DESIGN AND MEASUREMENTS: Experiments were carried out to clarify whether or not chondroitin sulfate inhibited pancreatic lipase activity in assay systems using triolein emulsified with phosphatidylcholine or gum arabic. In addition, the effects of chondroitin sulfate on lipid absorption by brush border membrane vesicles were examined. Moreover, mice were fed a high-fat diet and treated with chondroitin sulfate for 8 weeks. RESULTS: Chondroitin sulfate dose-dependently inhibited the pancreatic lipase activity in an assay system using triolein emulsified with phosphatidylcholine. In addition, chondroitin sulfate inhibited the palmitic acid uptake into the brush border membrane vesicles of the rat jejunum. Chondroitin sulfate caused the reduction of body weight and parametrial adipose tissue weight, and prevention of fatty liver and hyperlipidemia in mice fed a high-fat diet. CONCLUSION: The reduction of fat storage and the antihyperlipidemic action of chondroitin sulfate might be due to the inhibition of small intestinal absorption of dietary fat through the inhibition of pancreatic lipase activity and fatty acid uptake through brush border membrane.

Adipose Tissue↗
PubMed2000

Platycodi radix affects lipid metabolism in mice with high fat diet-induced obesity.

An aqueous extract of Platycodi radix inhibited the hydrolysis of triolein emulsified with phosphatidylcholine by pancreatic lipase in vitro and it reduced the elevation of rat plasma triacylglycerol level 2-4 h after oral administration of a lipid emulsion containing corn oil. These preliminary results suggested that the aqueous extract of Platycodi radix may inhibit the intestinal absorption of dietary fat by inhibiting its hydrolysis. Therefore, we examined the antiobesity activity of the aqueous extract of Platycodi radix by testing whether the extract prevented the obesity induced by feeding a high fat diet to mice for 8 wk. Body weights at 3-8 wk and the final parametrial adipose tissue weights were significantly lower in mice fed the high fat diet containing 5% aqueous extract of Platycodi radix than in the controls fed the high fat diet. The aqueous extract of Platycodi radix also significantly reduced hepatic triacylglycerol concentrations that were elevated in mice fed the high fat diet alone. Inulin, which is a major component of Platycodi radix, had no effect on the hydrolysis of triolein emulsified with phosphatidylcholine by pancreatic lipase in vitro, and did not prevent obesity or the fatty liver induced by the high fat diet. On the other hand, the total saponin fraction of the aqueous extract inhibited pancreatic lipase activity in vitro. Therefore, the antiobesity effect of the aqueous extract of Platycodi radix in mice fed a high fat diet may be due in part to the inhibition of intestinal absorption of dietary fat by the saponins of Platycodi radix.

Analysis of Variance↗
PubMed2000

Comparison of metabolic risk factors in patients with recurrent urolithiasis stratified according to age and gender.

OBJECTIVE: Little is known regarding the metabolic features associated with aging and gender in urolithiais patients. We compared the metabolic characteristics among 3 generations (young, middle-aged and old) with recurrent calcium-containing urinary stones. METHODS: One hundred and eighty-one patients with recurrent calcium-containing stones, including 71 patients aged </=45 years (group 1), 71 patients aged 46-60 years (group 2) and 39 patients aged >/=61 years (group 3), were investigated by metabolic evaluation. The frequencies of metabolic abnormalities, the value of each urinary constituent and the supersaturation index (AP(CaOx) index) were compared among subgroups of the 3 generations, containing both males and females. RESULTS: The number of metabolic abnormalities was the greatest in group 1, followed by group 2 and group 3. Hyperoxaluria was the most common abnormality in each group. Group 1 females showed a lower frequency of hypocitraturia than group 3 females. This was the only characteristic that showed a significant difference between the groups. Urinary calcium excretion was significantly greater in group 1 than in group 3. Urinary citrate excretion and the AP(CaOx) index were significantly higher in group 1 than in group 3 in females. Male patients had a significantly higher number of metabolic abnormalities than female patients, especially in group 1. CONCLUSION: Multiple metabolic abnormalities, particularly a high calcium excretion appear to be crucial factors in the development and recurrence of urolithiasis in young patients. Low urinary citrate excretion could play an important role in the occurrence of urolithiasis in elderly females.

Age Factors↗