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T Ogata

Publications and source records attributed to T Ogata.

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

Testis- and developmental stage-specific expression of hnRNP A2/B1 splicing isoforms, B0a/b.

Heterogeneous nuclear ribonucleoproteins (hnRNPs) A2 and B1 are abundant nuclear proteins that bind to nascent RNAs synthesized by RNA polymerase II. Previously we had found that the splicing isoforms hnRNP B0a/b, from which the ninth exon of the A2/B1 gene is excluded, are abundantly expressed in testis. We postulated that B0a/b are testis-specific isoforms, and investigated the expression of A2/B1 and B0a/b in rat tissues and in postnatal development of rat testes using RNase protection assay, immunoblotting, and immunohistochemistry. We found that hnRNP B0a/b mRNAs are expressed in several tissues but that the testis alone expresses B0a/b proteins. A sequential study using neonatal rat testes demonstrated that B0a/b mRNAs are produced after 17 days of age, but not translated until 4 weeks of age when round spermatids appear in addition to spermatogonia and spermatocytes. Immunohistochemically, hnRNP A2/B1 isoforms are expressed during spermatogenesis from spermatogonia through round spermatids, whereas the expression of A1 is restricted to spermatogonia. This expression pattern in the rat testis is maintained from birth through adulthood. These results suggest that the expression of the hnRNP A2/B1 gene is partly regulated by a testis-specific post-transcriptional mechanism, and that the products of the A2/B1 gene, especially hnRNP B0a/b, are involved in spermatogenesis.

Animals↗
PubMed2000

A member of a gene family on Xp22.3, VCX-A, is deleted in patients with X-linked nonspecific mental retardation.

X-linked nonspecific mental retardation (MRX) has a frequency of 0.15% in the male population and is caused by defects in several different genes on the human X chromosome. Genotype-phenotype correlations in male patients with a partial nullisomy of the X chromosome have suggested that at least one locus involved in MRX is on Xp22.3. Previous deletion mapping has shown that this gene resides between markers DXS1060 and DXS1139, a region encompassing approximately 1.5 Mb of DNA. Analyzing the DNA of 15 males with Xp deletions, we were able to narrow this MRX critical interval to approximately 15 kb of DNA. Only one gene, VCX-A (variably charged, X chromosome mRNA on CRI-S232A), was shown to reside in this interval. Because of a variable number of tandem 30-bp repeats in the VCX-A gene, the size of the predicted protein is 186-226 amino acids. VCX-A belongs to a gene family containing at least four nearly identical paralogues on Xp22.3 (VCX-A, -B, -B1, and -C) and two on Yq11.2 (VCY-D, VCY-E), suggesting that the X and Y copies were created by duplication events. We have found that VCX-A is retained in all patients with normal intelligence and is deleted in all patients with mental retardation. There is no correlation between the presence or absence of VCX-B1, -B, and VCX-C and mental status in our patients. These results suggest that VCX-A is sufficient to maintain normal mental development.

Amino Acid Sequence↗
PubMed2000

Imprinting of human GRB10 and its mutations in two patients with Russell-Silver syndrome.

Documentation of maternal uniparental disomy of chromosome 7 in 10% of patients with Russell-Silver syndrome (RSS), characterized by prenatal and postnatal growth retardation and dysmorphic features, has suggested the presence of an imprinted gene on chromosome 7 whose mutation is responsible for the RSS phenotype. Human GRB10 on chromosome 7, a homologue of the mouse imprinted gene Grb10, is a candidate, because GRB10 has a suppressive effect on growth, through its interaction with either the IGF-I receptor or the GH receptor, and two patients with RSS were shown to have a maternally derived duplication of 7p11-p13, encompassing GRB10. In the present study, we first demonstrated that the GRB10 gene is also monoallelically expressed in human fetal brain tissues and is transcribed from the maternally derived allele in somatic-cell hybrids. Hence, human GRB10 is imprinted. A mutation analysis of GRB10 in 58 unrelated patients with RSS identified, within the N-terminal domain of the protein, a P95S substitution in two patients with RSS. In these two cases, the mutant allele was inherited from the mother. The fact that monoallelic GRB10 expression was observed from the maternal allele in this study suggests but does not prove that these maternally transmitted mutant alleles contribute to the RSS phenotype.

Abnormalities, Multiple↗
PubMed2000

Structural analysis of a rare rearranged Y chromosome and its bearing on genotype-phenotype correlation.

We report on a 9-year-old boy with a rare rearranged Y chromosome and borderline short stature (-2.0 SD). Standard metaphase chromosome analysis indicated a 46,X,i(Y)(q1O) karyotype, but high resolution G-banding showed an asymmetric band pattern for the rearranged Y chromosome. FISH and DNA studies for a total of 15 different Y chromosomal loci or regions showed that the rearranged Y chromosome was accompanied by: 1) a partial deletion of the short arm pseudoautosomal region (PAR1) involving SHOX, with the breakpoint distal to DXYS85; and 2) a partial duplication of Yq, with the breakpoint proximal to DAZ. The karyotype was determined as 46,X,?i(Y)(q1O).ish der(Y)(Yqter--> Yp11.3::Yq11.2-->Yqter)(DAZ++,DYZ3+,SRY +, SHOX-). The X chromosome and the autosomes were normal. The results suggest that haploinsufficiency of SHOX is primarily responsible for the borderline short stature, and that the deletion of the PAR1 may result in spermatogenic failure due to defective X-Y pairing and recombination in the PAR1.

Child↗
PubMed2000

Mother and daughter with 45,X/46,X,r(X)(p22.3q28) and mental retardation: analysis of the X-inactivation patterns.

We report on a mother and daughter both with a 45,X/46,X,r(X)(p22. 3q28) karyotype and mental retardation. Fluorescence in situ hybridization (FISH) and microsatellite analyses for 14 loci/region at Xp22.3 and seven loci/region at Xq28 indicated that the ring X chromosome was missing a roughly 12-Mb region from Xp22.3 with the breakpoint between DXS85 and DXS9972, and another region of less than 100 kb from Xq28 with the breakpoint distal to the region defined by the FISH probe c8.2/1. X-inactivation analysis, using the methylation status of the AR gene (exon 1) as an indicator, showed that the normal and ring X chromosomes in the X,r(X)(p22.3q28) cell lineage were randomly inactivated. The Xp22.3 deleted region partially overlaps with the regional intervals of MRX19, MRX21, MRX24, MRX37, MRX43, and MRX49 associated with heterozygote manifestation. Therefore, it is likely that one or more of these MRX genes, subject to X-inactivation, are lost from the ring X chromosome, and that reduced expression of the MRX gene(s) caused by random X-inactivation has resulted in mental retardation in the mother and daughter.

Adult↗
PubMed2000

Morphological studies on the translocation of tubulovesicular system toward the intracellular canaliculus during stimulation of the gastric parietal cell.

The gastric parietal has two characteristic membrane systems. One is the intracellular canaliculus, which is specialized networks of enfolded luminal membrane channels lined with numerous microvilli. The other structures common to all parietal cells are the tubulovesicles or the tubulovesicular membranes, a system of tubules and vesicles. The tubulovesicular compartment is drastically depleted during maximal gastric acid secretion and this is coincident with an increase in the canalicular cell surface membrane. A plausible explanation for this redistribution is the fusion and transfer of tubulovesicular membranes to the plasma membrane. However, for many years there was no convincing evidence of connections between these two membrane systems. The mechanism of the transformation of tubulovesicular membrane into the plasma membrane without demonstrable connections has been an enigma to electron microscopists. Using a recently developed fixation technique for parietal cells [Sugai et al. (1995) Acta Anat Nippon 74:S101], we have investigated the organization of the cytoplasmic membrane systems in the rat resting and tetragastrin stimulated stomachs by ultra-high-resolution scanning electron microscopy (SEM). Gastric mucosae were microwave-fixed in a cacodylate buffer, (334 milliosmoles/kgH(2)O (mOsm)), to which 1.0% glutaraldehyde and 0.5% formaldehyde were added. Specimens examined by TEM of thin sections revealed the cytoplasm packed with tubular membranes similar to images detected by rapid-freeze/freeze-substitution fixation. To render the cytoplasmic membranes visible by SEM, fixed mucosae were treated by the aldehyde-osmium-DMSO-osmium maceration procedure. With much of the cell matrix and filaments removed, SEM revealed numerous 30-60-nm tubules, which formed a meshwork with small cisternae. Vesicles or isolated tubules were not found in adequately macerated parietal cells. The cytoplasmic surface of the intracellular canaliculus was smooth except for round openings representing the bases of macerated microvilli. In favorable sites, connections of the tubular membranes to the canaliculi were clearly visible. Stereo pair views were particularly useful to demonstrate these continuities. Connections between these two membrane compartments suggest the probability of rapid membrane transposition. In this article, the form and distribution of membrane systems of parietal cells in the resting state and after tetragastrin stimulation will be presented and discussed. Special emphasis is made to demonstrate connections between the tubulovesicular system and the intracellular canaliculus.

Animals↗
PubMed2000

Scanning EM of resting gastric parietal cells reveals a network of cytoplasmic tubules and cisternae connected to the intracellular canaliculus.

Using a recently developed fixation technique for parietal cells (Sugai et al., Acta Anat Nippon 1995:70:S79, 1999:74:S101), we have reinvestigated the organization of the cytoplasmic membrane system in the resting stomach by ultra-high-resolution scanning electron microscopy (SEM). Rat gastric mucosae were microwave-fixed in cacodylate buffer [334 milliosmoles/kg H(2)O (mOsm)], to which 1.0% glutaraldehyde and 0.5% formaldehyde were added. Specimens examined by transmission electron microscopy (TEM) of thin sections revealed cytoplasm packed with tubular membranes similar to images detected by rapid-freeze/freeze-substitution fixation which is generally considered to cause minimal structural alterations. To render the cytoplasmic membranes visible by SEM, fixed mucosae were frozen, fractured, and the exposed cytoplasm of parietal cells was macerated by the aldehyde-osmium-DMSO-osmium procedure. With much of the cell matrix and filaments removed, SEM revealed numerous 30-60 nm tubules which formed a meshwork and also small cisternae. The cytoplasmic surface of the tubules was smooth while some cisternal areas had attached polyribosomes. Vesicles or isolated tubules were not found in appropriately macerated parietal cells. The cytoplasmic surface of the intracellular canaliculus was smooth except for round openings representing the bases of macerated microvilli. In favorable sites connections of the tubular membranes to the canaliculi were clearly visible. Stereo pair views were particularly useful to demonstrate these continuities. Connections between these two membrane compartments suggest the probability of rapid membrane transposition.

Animals↗
PubMed2000

Proteome analysis of Oncorhynchus species during embryogenesis.

To understand the molecular mechanisms underlying normal and abnormal development of two salmonids, masu salmon (Oncorhynchus masou) and rainbow trout (O. mykiss), we used two-dimensional (2-D) electrophoresis to construct a series of 2-D maps during the embryonic period. We identified all visible protein spots on the 2-D map by assigning numbers for masu salmon and rainbow trout, and we determined N-terminal sequences of proteins for one hundred of the spots, that appear at very high concentrations in the whole embryos of masu salmon and rainbow trout. We also characterized embryonic stages according to the periods of appearance of spots. Most of the N-terminal sequences were identical or at least highly similar to partial sequences reported for vitellogenin (Vtg) of O. mykiss. A potential proteolytic processing of Vtg for rainbow trout is discussed in relation to the time of appearance and relative position of Vtg fragments within the complete protein sequence.

Amino Acid Sequence↗
PubMed2000

Release characteristics of a short-chain fatty acid, n-butyric acid, from its beta-cyclodextrin ester conjugate in rat biological media.

6(A)-O-(n-Butanoyl)-beta-cyclodextrin was prepared and its hydrolysis behavior in aqueous solutions and in rat intestinal fluids was investigated. Furthermore, the enzymatic hydrolyses of the n-butyric acid-beta-cyclodextrin conjugate using alpha-amylase and esterase were studied to gain insight into the release behavior of n-butyric acid from the conjugate. The hydrolysis of the conjugate proceeded according to a first-order kinetics in aqueous solution, and gave a V-shaped pH profile, indicating a specific acid-base-catalyzed hydrolysis at acidic and neutral-alkaline regions, respectively. The half-lives (t(1/2)) of the conjugate at pH 4.4, 6.8, and 7.4 at 37 degrees C were approximately 580, 43, and 6 days, respectively, indicating that the conjugate is stable in aqueous solution. No appreciable release of n-butyric acid from the conjugate was observed in the stomach and small intestinal contents of rats, or in the small and large intestinal homogenates of rats. On the other hand, a fast disappearance of the conjugate and an appearance of n-butyric acid were observed in the cecal and colonic contents of rats. The t(1/2) values of the disappearance were approximately 4, 1, and 6 h in 10 and 15% cecal contents and 10% colonic contents, respectively, and the appearance of n-butyric acid after 6 h was approximately 10% in the 15% cecal contents. Aspergillus oryzae alpha-amylase hydrolyzed the conjugate to small saccharide conjugates, such as the triose and maltose conjugates, but there was no appreciable release of n-butyric acid. The conjugate was less susceptible to carboxylic esterase (from porcine live), thus releasing no appreciable amounts of n-butyric acid. On the other hand, a fast release of n-butyric acid was observed when the esterase was employed after amylase hydrolysis, suggesting that two types of enzymes, sugar-degrading and ester-hydrolyzing enzymes, are necessary for the release of n-butyric acid from the conjugate in large intestinal contents.

Animals↗
PubMed2000

Testicular volume in Japanese boys up to the age of 15 years.

UNLABELLED: Previous studies have indicated that Japanese children grow and mature significantly faster than Caucasian children, thus calling for a separate reference standard for each skeletal and sexual maturity index. To establish normal reference values for testicular volume in Japanese boys, we studied from 1985 to 1995, 900 healthy male children of 0 to 15 years of age for medical history, physical examination, height, weight, sitting height, and head circumference measurements, Tanner sex maturity stage, and testicular size. The testicular volume was determined using a Prader orchidometer by the same observer (N.M.). Based on these data, we established the cross-sectional percentile growth curves (90th, 50th, 10th percentiles) for testicular volume of Japanese boys. The testicular volume of 3 ml was attained at 9.3 years of age (90th percentile), 11.0 years of age (50th percentile), and 12.1 years of age (10th percentile), respectively. CONCLUSION: Swelling of the testis in Japanese children begins approximately 1 year earlier than in Swiss children in accordance with the earlier skeletal maturation in Japanese children.

Adolescent↗
PubMed2000

Clinical and molecular studies in 15 females with ring X chromosomes: implications for r(X) formation and mental development.

We report clinical and molecular findings in 15 Japanese mosaic females with r(X) chromosomes, 45,X/46,X,r(X), confirmed by fluorescence in situ hybridization (FISH) analysis for DXZ1 and whole X chromosome painting. Cases 1-3, 5-7, and 11-13 had mental retardation (MR), the remaining cases being free from MR. FISH analysis showed that XIST was absent from the r(X) chromosomes in cases 1-4 and was present on the r(X) chromosomes in cases 5-15. X-inactivation analysis for the methylation status of the AR gene indicated that, of eight cases with XIST-positive r(X) chromosomes in more than 10% (23%-62%) of lymphocytes (cases 5-12), cases 5-10 had selective X-inactivation, whereas cases 11 and 12 had active X disomy. Microsatellite analysis for multiple loci on the pericentromeric region revealed that, of 11 cases with r(X) chromosomes in more than 10% (13%-62%) of lymphocytes (cases 1, 2, and 4-12), cases 1, 2, and 5-10 had heterozygous alleles for at least one locus, whereas cases 4, 11, and 12 had single alleles for all the loci examined. The results suggest that the r(X) and normal X chromosomes could be of biparental or uniparental origin, and that mental status in females with r(X) chromosomes is determined by multiple factors, including the presence or absence of XIST on the r(X) chromosomes and the size and frequency of active r(X) chromosomes, in addition to co-incidental genetic and environmental factors.

Adolescent↗
PubMed2000

Del(X)(p21.1) in a mother and two daughters: genotype-phenotype correlation of Turner features.

We report a mother and two daughters with partial Xp monosomy. Clinical assessment for Turner phenotype revealed that the three females manifested low-normal to mild short stature (-1.6 to approximately -2.3 SD) and variable degrees of skeletal features, such as cubitus valgus, short 4th matacarpals, and Madelung deformity, but no soft tissue or visceral anomalies or gonadal dysfunction. Cytogenetic studies for lymphocytes showed that the karyotype was 45,X[3]/46,X,del(X)(p21.1)[27] in the mother and non-mosaic 46,X,del(X)(p21.1) in the two daughters. Fluorescence in situ hybridization and microsatellite analyses for 19 loci/regions on the X chromosome demonstrated that the del(Xp) chromosome was missing SHOX and had the breakpoint between DMD and CYBB. The results are consistent with the recently proposed notion that haploinsufficiency of SHOX results in not only short stature, but also Turner skeletal features in association with maturational effects of gonadal estrogens. The lack of soft tissue or visceral anomalies suggests the presence of the putative lymphogenic gene on the del(Xp) chromosome; the preservation of ovarian function appears to be compatible with meiotic pairing failure being relatively mild.

Adolescent↗
PubMed2000

Inducible expression of basic transcription element-binding protein 2 in proliferating smooth muscle cells at the vascular anastomotic stricture.

OBJECTIVE: The proliferation of vascular smooth muscle cells surrounding a suture line is an important factor in the development of anastomotic stricture that is frequently seen after coronary artery bypass grafting. The aim of this study was to investigate the time course of intimal thickening and to examine the expression of the molecular marker of smooth muscle cell activation surrounding the suture line. METHODS: Longitudinal aortotomy was performed in the abdominal aorta of rats. The rats were put to death 1, 2, 4, and 8 weeks after aortotomy, and the percentage of the lumen occluded by intimal thickening was calculated. All tissues were stained with antibodies against basic transcription element- binding protein 2, human cyclin-dependent kinase (cdk4), and Sp1 for immunohistochemistry. Basic transcription element-binding protein 2 is a transcription factor that is involved in phenotypic modulation of vascular smooth muscle cells. Cdk4 represents a marker for G(1) phase of the cell cycle. Sp1 is a transcription factor known to be expressed in a variety of tissues. Basic transcription element-binding protein 2 messenger RNA expression was confirmed by means of reverse transcriptase-polymerase chain reaction. RESULTS: We noted significant thickening of the intimal layer 1 week after aortotomy. Immunohistochemistry demonstrated that smooth muscle cells in the neointima were strongly positive for basic transcription element-binding protein 2 and human cyclin-dependent kinase 4, which peaked 2 weeks after aortotomy. Basic transcription element-binding protein 2 expression was closely associated with human cyclin-dependent kinase 4 expression in the neointima, although Sp1 was not. Basic transcription element-binding protein 2 messenger RNA levels were significantly up-regulated early after aortotomy. CONCLUSION: The experimental rat aortotomy model is useful to investigate the proliferation of vascular smooth muscle cells around the suture line. Moreover, our results suggest the possible role of basic transcription element-binding protein 2 in the development of vascular anastomotic strictures.

Anastomosis, Surgical↗
PubMed2000

Frequent occurrence of paralytic shellfish poisoning toxins as dominant toxins in marine puffer from tropical water.

Considerably high toxicity was detected in marine puffers collected from Masinloc Bay, Philippines. The toxicity was detected in the liver, intestine, muscle and skin. Noteworthy, the specimens, the muscle of which showed high toxicity, appeared in high frequency, indicating that puffers from this area is not safe for human consumption. These puffer specimens contained paralytic shellfish poisoning (PSP) toxins, often as major toxin components, the profile of which was similar to that of freshwater puffers reported from tropical areas. These results indicate that PSP toxins are common in tropical puffers both from marine and freshwater.

Animals↗
PubMed2000

Dependence of sonochemical luminescence on various sound fields

To understand the effect of the sound field on sonochemical luminescence, the exact sound pressure must be determined in each field. In this study it was determined by the Shlieren method, which measures the sound pressure without mixing the sound fields. We compared the efficiency of the sonochemical luminescence in three different ways: changing the diameter of the transducer, combining two transducers to obtain crossed propagating directions and surrounding the sound field by a glass cylinder. In the last case cylinders with various sizes were studied. We found that (i) at the same sound pressure, the larger transducer induces stronger luminescence per unit volume, (ii) driving two transducers produces stronger luminescence than the sum of each transducer and (iii) a glass cylinder surrounding the sound field induces stronger luminescence.

Journal Article↗
PubMed2000

Novel mutations of the ACTH receptor gene in a female adult patient with adrenal unresponsiveness to ACTH.

We report a 30-year-old female with adrenal unresponsiveness to ACTH. Her clinical features included no adrenal crisis despite poor drug compliance, poor pubic hair development (Tanner stage 2), well-developed breasts (Tanner stage 5), and regular menstrual cycles. Endocrinological data included blood ACTH 1500 pmol/l, cortisol 18 nmol/l, dehydroepiandrosterone sulphate below 0.26 micromol/l, activated renin 0.37 pmol/l, and aldosterone 3.4 nmol/l. Direct sequencing and allele-specific amplification revealed two novel mutations in the ACTH receptor gene. One was transition from guanine to adenine at nucleotide position 1002, resulting in substitution of aspartate for asparagine at codon 103, and the other was transition from cytosine to thymine at nucleotide 1104, leading to substitution of arginine for tryptophan at codon 137. The present findings lend additional credence to the notions that adrenal androgens play an important role in female pubic hair development and that ovarian development takes place independently of adrenarche.

Adrenal Gland Diseases↗