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Biomedical subjects

T Hosoda

Publications and source records attributed to T Hosoda.

At least 19 recordsLinked to original sources
PubMed2000

Cloning of murine glycosyl phosphatidylinositol anchor attachment protein, GPAA1.

Glycosyl phosphatidylinositols (GPIs) are used to anchor many proteins to the cell surface membrane and are utilized in all eukaryotic cells. GPI anchoring units are attached to proteins via a transamidase reaction mediated by a GPI transamidase complex. We isolated one of the components of this complex, mGPAA1 (murine GPI anchor attachment), by the signal sequence trap method. mGPAA1 cDNA is about 2 kb in length and encodes a putative 621 amino acid protein. The mGPAA1 gene has 12 small exons and 11 small introns. mGPAA1 mRNA is ubiquitously expressed in mammalian cells, and in situ hybridization analysis revealed that it is abundant in the choroid plexus, skeletal muscle, osteoblasts of rib, and occipital bone in mouse embryos. Its expression levels and transamidation efficiency decreased with differentiation of embryonic stem cells. The 3T3 cell lines expressing antisense mGPAA1 failed to express GPI-anchored proteins on the cell surface membrane.

3T3 Cells↗
PubMed2000

Determination of the complete nucleotide sequence and haplotypes in the D-loop region of the mitochondrial genome in the oriental white stork, Ciconia boyciana.

The complete nucleotide sequence of the mitochondrial genome of the Oriental white stork, Ciconia boyciana, has been determined from captive storks by a novel method incorporating Long PCR and shotgun sequencing. 13 protein-coding genes, two ribosomal RNA genes and 22 transfer RNA genes were identified as in other vertebrate mitochondrial genomes. The position and direction of the NADH6 and tRNA-Glu genes were the same as previously reported for avian mitochondrial genomes. A 71 bp direct repeat and long CAAA repeat sequences were found at the 3' end of the D-loop region, together with SCB-1, SCB-2, SCB-3, and three TAS sequences. Direct sequencing of the PCR fragments in the D-loop region in 26 captive Oriental white storks originating from Japan, China, and Russia revealed nucleotide differences at 18 sites along 1,248 bp, and a total of nine haplotypes have been identified. It was found that one pair of individuals in the Japanese captive breeding program were of the same haplotype, suggesting that they were caught from the same nest. The pair has since been dissolved in consideration of the possibility of inbreeding depression.

Animals↗
PubMed1999

Differential age effect of oral administration of an antigen on antibody response: an induction of tolerance in young mice but enhancement of immune response in old mice.

Sheep red blood cells (SRBC) were orally administered to young (4 months old) and old (22 months old) mice, and its effect on the antibody production after systemic immunization was compared between young and old mice. The results showed that the dose-dependent suppression of antibody response (oral tolerance) was observed in young mice which had been previously treated with oral administration of SRBC. On the contrary, the enhancement of antibody production was observed in old mice which had been treated in the same way. The enhanced level of IgG antibody in old mice was higher than that of young mice. The critical age determining either suppression or enhancement of antibody response after the oral administration of the antigen was present between 6.5 and 10.5 months of age. When the oral administration of the antigen was performed in young (3 months old) and middle-aged mice (12 months old), the oral tolerance for young and the enhanced antibody response for middle-aged mice were observed even at 6 months after the treatment. The analysis by in vitro antibody response using T and B cells prepared from young and old mice showed that age-related alteration of T and B cells is responsible for the suppression and the enhancement of antibody response after oral administration of SRBC, respectively.

Administration, Oral↗
PubMed1999

Bone morphogenetic proteins induce cardiomyocyte differentiation through the mitogen-activated protein kinase kinase kinase TAK1 and cardiac transcription factors Csx/Nkx-2.5 and GATA-4.

Bone morphogenetic proteins (BMPs) have been shown to induce ectopic expression of cardiac transcription factors and beating cardiomyocytes in nonprecardiac mesodermal cells in chicks, suggesting that BMPs are inductive signaling molecules that participate in the development of the heart. However, the precise molecular mechanisms by which BMPs regulate cardiac development are largely unknown. In the present study, we examined the molecular mechanisms by which BMPs induce cardiac differentiation by using the P19CL6 in vitro cardiomyocyte differentiation system, a clonal derivative of P19 embryonic teratocarcinoma cells. We established a permanent P19CL6 cell line, P19CL6noggin, which constitutively overexpresses the BMP antagonist noggin. Although almost all parental P19CL6 cells differentiate into beating cardiomyocytes when treated with 1% dimethyl sulfoxide, P19CL6noggin cells did not differentiate into beating cardiomyocytes nor did they express cardiac transcription factors or contractile protein genes. The failure of differentiation was rescued by overexpression of BMP-2 or addition of BMP protein to the culture media, indicating that BMPs were indispensable for cardiomyocyte differentiation in this system. Overexpression of TAK1, a member of the mitogen-activated protein kinase kinase kinase superfamily which transduces BMP signaling, restored the ability of P19CL6noggin cells to differentiate into cardiomyocytes and concomitantly express cardiac genes, whereas overexpression of the dominant negative form of TAK1 in parental P19CL6 cells inhibited cardiomyocyte differentiation. Overexpression of both cardiac transcription factors Csx/Nkx-2.5 and GATA-4 but not of Csx/Nkx-2.5 or GATA-4 alone also induced differentiation of P19CL6noggin cells into cardiomyocytes. These results suggest that TAK1, Csx/Nkx-2.5, and GATA-4 play a pivotal role in the cardiogenic BMP signaling pathway.

Bone Morphogenetic Proteins↗
PubMed1999

Familial atrial septal defect and atrioventricular conduction disturbance associated with a point mutation in the cardiac homeobox gene CSX/NKX2-5 in a Japanese patient.

Atrial septal defect (ASD) is the most common form of congenital cardiac defect in humans. Recently, point mutations in the cardiac homeobox gene CSX/NKX2-5 have been reported to cause the autosomal dominant form of familial ASD. Notably, all the affected patients exhibit atrioventricular conduction disturbance and some of them died suddenly. The first case of familial ASD with a mutation of the CSX/NKX2-5 gene in a Japanese patient is reported here. Identification of CSX/NKX2-5 mutations in ASD patients would be very important because the existence of such mutations may predict sudden cardiac death.

Heart Block↗
PubMed1998

Molecular cloning of human homolog of yeast GAA1 which is required for attachment of glycosylphosphatidylinositols to proteins.

Anchoring proteins to cell surface membranes by glycosylphosphatidylinositols (GPIs) is important. We have isolated a component of the putative transamidase machinery, hGaa1p (human GPI anchor attachment protein). hGAA1 cDNA is approximately 2 kb in length and codes 621 amino acids. The amino acid sequence of hGaa1p is 25%, identical and 57% homologous to that of yeast Gaa1p. Moreover, Kite-Dolittle hydrophobicity plots of both proteins show marked similarity. hGAA1 gene is expressed ubiquitously and mRNA levels are higher in the undifferentiated state. Overexpression of antisense hGAA1 in human K562 cells significantly reduced the production of a reporter GPI-anchored protein.

Amino Acid Sequence↗
PubMed1997

Identification of the sex of Oriental white stork, Ciconia boyciana, by the polymerase chain reaction based on its sex chromosome-specific DNA sequences.

Southern blotting of HindIII-digested genomic DNAs from the female and male Oriental white stork (Ciconia boyciana) with the EE0.6 probe cloned from the W chromosome of chicken (Gallus domesticus) produced a 3.0-kb W chromosome-derived band specific to the female and a 3.5-kb Z chromosome-derived band common to both sexes. These two genomic fragments were cloned and the counterpart sequences to that of EE0.6 in these fragments, XH0.6 and XH0.6RSM (XH0.6-related sequence in the male), respectively, were subcloned. Nucleotide sequences of XH0.6 and XH0.6RSM showed 92% identity. PCR using a set of primer sequences from XH0.6, which differed several nucleotides from those in XH0.6RSM, amplified an about 300-bp genomic sequence only from the female C. boyciana. This method was applied successfully to identify the sex of individual young birds of C. boyciana, an endangered special natural monument in Japan and whose sexes are unidentifiable from their external morphology.

Animals↗
PubMed1995

[A case of pulmonary infiltration with eosinophilia (PIE) syndrome associated with syndrome of inappropriate secretion of ADH (SIADH) in the elderly patient].

A 76-year-old woman was admitted to our hospital because of productive cough, fever and anorexia in January 1995. She had suffered from bronchial asthma for 25 years. From 1983, exacerbation of PIE was recorded three times, on which occasions prednisolone and antibiotics were quite effective. On admission, marked leukocytosis (28,000/microliters) and eosinophilia (18,000/microliters) were found. However, plasma IgE level was normal, and specific antigen for eosinophilia was not detected by RAST or the skin allergic reaction test. Chest X-ray film and CT scan revealed extensive bilateral pulmonary infiltration. Increase in eosinophils (33%) was demonstrated in bronchoalveolar lavage. Furthermore, biopsy specimen of the affected lung revealed diffuse infiltration of eosinophils into alveolar septa. On the basis of these findings, the patient was diagnosed as chronic eosinophilic pneumonia (PIE syndrome). Hyponatremia (117 mEq/l) was persistent after the hydration with normal saline. Plasma ADH was not suppressed (2.29 pg/ml) in spite of hypoosmolality of plasma. Laboratory examination showed that renal, adrenal and thyroid function as well as plasma renin activity were normal. Taking these findings together, she was diagnosed as having SIADH. Treatment with prednisolone improved not only the PIE syndrome but also SIADH.

Aged↗
PubMed1994

Phylogenetic relationship between the Iriomote cat and the leopard cat, Felis bengalensis, based on the ribosomal DNA.

We analyzed the restriction fragment length polymorphisms in the spacer regions of ribosomal DNA (rDNA), using twelve restriction enzymes, to examine whether the Iriomote cat is related to the leopard cat (Felis bengalensis). A restriction map for each taxon was constructed and the major taxon-specific types of repeating unit (repetypes) were characterized on the basis of the arrangements of restriction sites. The Iriomote cat and the leopard cat share a common repetype but this repetype is different from that of the domestic cat (F. catus) with an estimated sequence divergence of 1.5% and from that of the ocelot (F. paradalis) with an estimated sequence divergence of 2.5%. These results indicate that, phylogenetically, the Iriomote cat is closely related to the leopard cat and that the ancestral population moved from the continent to Iriomote Island quite recently. The rDNA arrays of the leopard cat exhibit considerable intragenomic size-variation, which is thought to have emerged as a result of differences in numbers of repeated DNA segments, whereas the extent of such size-variation is much lower in the rDNA of the Iriomote cat. It appears that, even though migration of the Iriomote cat occurred relatively recently, the population has diverged to some extent from its continental counterpart, perhaps via fixation of preexistent intraspecific variations rather than by generation of new variations.

Animals↗
PubMed1993

[HCV subtypes and their clinical significance].

We immunologically isolated a clone with a 177-bp DNA fragment, designated as #2-22, that had homology to the NS-5 region of a HCV genome. To classify this HCV isolate, we sequenced several clones (2028 bases in total) from a cDNA library constructed from a #2-22-positive patient's blood. They showed distinct similarity to the HC-J8 genome (type II b), among the known HCV subtypes. Using this #2-22 sequence for PCR, we screened the HCV-positive blood samples from Southern Kyushu, we could identify 27% of them as type II b. In another cDNA library, from a single blood donor, who did not have multiple infections of HCV, we found two clones that might have arisen from an ancestral (or previous or historical) intergenomic recombination. They had reversed orders of similarity to different HCV subtypes, that is, the first 149-bp clone had 94% identical bases with a segment of HC-J8 and 78% with the corresponding sequence of HC-J6, but the second 814-bp clone had 85% identical bases with a segment of HC-J8 and 94% to the corresponding sequence of HC-J6. The importance of subtype analysis is discussed in relation to its clinical application, such as diagnostics development.

Amino Acid Sequence↗
PubMed1992

Characterization of cationic acid phosphatase isozyme from rat liver mitochondria.

Acid phosphatase isozyme was highly purified from rat liver mitochondrial fraction. The enzyme showed an isoelectric point value of above 9.5 on isoelectric focusing, and the apparent molecular weight was estimated to be 32000 by Sephadex G-100 gel filtration or 16000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The enzyme catalyzed the hydrolysis of adenosine 5'-triphosphate, adenosine 5'-diphosphate, thiamine pyrophosphate, inorganic pyrophosphate, and phosphoprotein such as casein and phosvitin, but not of several phosphomonoesters, except for p-nitrophenyl phosphate and o-phosphotyrosine. The enzyme was not inhibited by L-(+)-tartrate, and was significantly activated by Fe2+ and reducing agents such as ascorbic acid, L-cysteine,and dithiothreitol. The enzyme was found to be distributed in various rat tissues including liver, spleen, kidney, small intestine, lung, stomach, brain and heart, but not in skeletal muscle.

Acid Phosphatase↗
PubMed1991

[Ileal absorption of various amino acids and dipeptides in rats administered cyclophosphamide--using the short-circuit current method].

Transport of amino acids; glycine, L-alanine, L-leucine, L-proline, L-lysine and dipeptides; gly-gly, gly-L-pro, gly-L-leu, L-leu-gly was investigated by measuring the short-circuit current in control rats and the rats 3 days after intraperitoneal injection of cyclophosphamide (CPM) 300 mg/kg. For determining active transport using the short-circuit current method in injured intestinal epithelia the short-circuit current measured should be corrected for the decrease in the mucosal resistance of CPM group. Jmax values for transport of glycine and L-alanine in ileum are significantly decreased in CPM group than in control group. Contrariwise, there are no differences in Jmax values for peptides transport in ileum between two groups. The results indicate that the glycine transport carrier is more sensitive to CPM injury than the peptide transport carrier for glycine-containing dipeptide, suggesting the clinical usefulness of the peptide nutrition during chemotherapy.

Amino Acids↗
PubMed1991

[A case of sarcoidosis with increased CD3+ WT31- CD16+ lymphocytes].

Increase of CD16+ cells in the peripheral blood is not uncommon for sarcoidosis. However, further subclassification of such cells have not been reported yet. Here, we report a case of sarcoidosis developed in 71 year-old female who had abundant CD16+ lymphocytes in the peripheral blood and most of them were revealed to be CD3+ WT31- by analysis using cell sorting. Although exact role of these cells is remained to be solved, they seem to be implicated in the immune disorder of this disease.

Aged↗
PubMed1989

Cell-mediated suppression of human hematopoiesis: evaluation by limiting-dilution analysis of hematopoietic progenitors.

We have used limiting-dilution clonal analysis (LDA) in microwells to study the inhibitory effects of T lymphocytes (T-cells) or natural killer (NK) cells on human marrow progenitor cell growth. In four subjects with normal hematopoiesis, the growth of progenitors showed single-hit kinetics both before and after T-cell removal, indicating that, in the presence of colony-stimulating activity, T-cell have no effect on progenitor growth. In a patient with marrow hypoplasia associated with thymoma, hypogammaglobulinemia, and an increased number of suppressor T-cells (Good's syndrome), the progenitor growth deviated from linearity, demonstrating the presence of cells with suppressor activity. After T-cells were removed from this sample, the progenitor growth showed single-hit kinetics. The suppressive action of E-rosette-positive cells with NK or cytotoxic activities was also suggested in a patient with severe combined immune deficiency and in a patient with T gamma lymphocytosis. Poor progenitor-cell growth in three other patients with aplastic anemia was not significantly altered by T-cell removal. Thus, LDA of human hematopoietic progenitors is useful for evaluating cell-mediated interactions affecting hematopoiesis. This method may facilitate elucidation of mechanisms of myelosuppression in clinical settings.

Anemia, Aplastic↗