Biomedical subjects

A Hachisuka

Publications and source records attributed to A Hachisuka.

7 recordsLinked to original sources

PubMed2005

Postnatal expression profile of OBCAM implies its involvement in visual cortex development and plasticity.

This study examined the expression of a neuron-specific cell adhesion molecule, OBCAM (opioid-binding cell adhesion molecule), at both the mRNA and protein levels in the cat primary visual cortex at various postnatal ages, using cDNA array analysis and immunocytochemistry. Results obtained using both methods showed that the expression level of OBCAM was high in young and low in older and adult visual cortex. OBCAM-immunoreactivities were associated predominantly with perikarya and dendrites of pyramidal neurons, and OBCAM-immunopositive neurons were present in all cortical layers. Immunostaining of OBCAM in adult visual cortex showed a reduced number of immunopositive neurons and neurites and relatively lower staining intensities as compared with younger animals. In addition, the number of OBCAM-immunopositive neurons was significantly higher in the visual cortex of 4-month-old animals dark-reared from birth than those in age-matched normally reared animals. These results suggest that OBCAM may play an important role in visual cortex development and plasticity.

Aging↗

PubMed2002

Gene expression patterns during enhanced periods of visual cortex plasticity.

During a critical period in its postnatal development the mammalian visual cortex displays susceptibility to experience-dependent alterations of neuronal response properties. Plasticity represents an integrated set of developmental processes controlled by a transcriptional hierarchy that coordinates the action of many genes. To illuminate the expression of these critical genes, we examined gene expression patterns of 18371 non-redundant cDNAs in the visual cortex of cats at birth, at eye opening, at the peak of the critical period of eye dominance plasticity and in the adult cat using filter-based cDNA arrays and software-based hierarchical cluster analysis. We identified a small set of genes that were selectively expressed during the peak of the critical period for plasticity. We further examined the patterns of expression of these genes by analyzing the gene expression pattern of dark-reared chronologically older animals that are known to retain this ocular dominance plasticity beyond the chronologically defined critical period. This additional cluster assessment allowed us to separate age-related changes in the patterns of gene expression from plasticity-related changes, thus identifying a subset of genes that we define as plasticity candidate genes. Those plasticity candidate genes that have previously characterized functions include participants in second messenger systems, in cell adhesion, in transmitter recycling and cytokines, among others. Comparison of cDNA array quantitation with reverse transcription-polymerase chain reaction showed almost identical expression profiles for three genes that we examined. The expression pattern of one identified gene, opioid binding cell adhesion molecule, from the cDNA array analysis, is also in agreement with immunocytochemical results. We conclude that the approach of high-density cDNA array hybridization can be used as a useful tool for examining a complex phenomenon of developmental plasticity since it is amenable to multiple developmental stage gene expression comparisons.

Animals↗

PubMed2000

Developmental expression of opioid-binding cell adhesion molecule (OBCAM) in rat brain.

Opioid-binding cell adhesion molecule (OBCAM), a neuron-specific protein, consists of three immunoglobulin (Ig)-like domains anchored to the membrane through a glycosylphosphatidylinositol (GPI)-tail. OBCAM has been presumed to play a role as a cell adhesion/recognition molecule, but its function has not been fully elucidated. We investigated the developmental expression of OBCAM in rat brain by using a monoclonal anti-OBCAM peptide antibody (OBC53). OBCAM was clearly detectable on embryonic day 16 (E16) as assessed by immunoblotting. The expression level increased by the second postnatal week and was maintained at a constant level until week 17. During the early developmental period OBCAM was found to be expressed on postmitotic neurons and to be strongly expressed in at the fiber tracts containing expanding axons, in contrast to the adult brain, in which OBCAM is principally expressed in the gray matter. These findings suggest that the function of OBCAM involves axonal outgrowth.

Aging↗

PubMed1999

Localization of opioid-binding cell adhesion molecule (OBCAM) in adult rat brain.

We investigated the tissue distribution and brain localization of opioid-binding cell adhesion molecule (OBCAM) in the adult rats by immunoblotting and immunohistochemistry using a monoclonal anti-OBCAM peptide antibody that is specific for OBCAM. OBCAM was preferentially expressed in the central nervous system (CNS) and at a very low level in the spleen. Within the brain, OBCAM was distributed in almost all the gray matter, but little or no immunoreactive OBCAM was found in the white matter. Morphologically, the distribution pattern of OBCAM immunoreactivity was very similar to that of synaptophysin, suggesting a role in the synaptic machinery.

Animals↗

PubMed1997

Expression of opioid-binding cell adhesion molecule (OBCAM) and neurotrimin (NTM) in E. coli and their reactivity with monoclonal anti-OBCAM antibody.

Opioid-binding cell adhesion molecule (OBCAM), neurotrimin (NTM) and limbic system-associated membrane protein (LAMP) are homologous and are the members of the IgLON family which is a subfamily within the immunoglobulin superfamily. We cloned the cDNAs for OBCAM and NTM, prepared recombinant proteins, and examined the reactivity of the previously prepared monocolonal anti-OBCAM antibody, OBC53, with the recombinant proteins by immunoblotting. These experiments revealed that OBC53 recognizes OBCAM about 1000 times as efficiently as NTM. Moreover, the NTM and LAMP peptides which have sequences homologous to the OBCAM peptide used for the preparation of OBC53 were 150 times less reactive to OBC53. Thus, the OBC53 antibody is a useful tool for specifically detecting OBCAM in immunochemical experiments.

Amino Acid Sequence↗

PubMed1996

Characterization and tissue distribution of opioid-binding cell adhesion molecule (OBCAM) using monoclonal antibodies.

Monoclonal antibodies to opioid-binding cell adhesion molecule (OBCAM) were produced against a synthetic OBCAM peptide. Immunoblotting analysis revealed that the antibodies reacted with 58 and/or 51 kDa proteins in P2 membranes from bovine, rat, mouse, guinea pig and rabbit brains. In bovine brain, the 58 and 51 kDa proteins were present in the striatum and cerebral cortex at high levels, but not in the pituitary. OBCAM was also detected in the cerebellum mainly in the 51 kDa form. In other tissues, the proteins were found in the spleen at very low levels, but not at all in the liver or kidney of the rat. OBCAM was effectively solubilized from bovine P2 membranes by bacterial phosphatidylinositol specific-phospholipase C (PI-PLC), indicating that OBCAM is a glycosylphosphatidylinositol (GPI)-anchored protein. PI-PLC treatment, however, had little effect on the opioid binding activity of the residual P2 membranes. The molecular weight of the proteins (58 and 51 kDa) was reduced to 36 kDa following treatment with N-glycanase but not further reduced after subsequent treatment with neuraminidase and O-glycanase, suggesting that OBCAM has N-glycosylated carbohydrate chains and that its two isoforms are different, at least, in the degree of N-glycosylation. Taken together, these results suggest that OBCAM consists of 58/51 kDa GPI-anchored glycoproteins which are highly N-glycosylated and are expressed mainly in the nervous system.

Amino Acid Sequence↗

PubMed1993

[Evaluation of immunotoxicity tests using cyclosporin A-treated rats: the International Collaborative Immunotoxicity Study II (cyclosporin A)].

Immunotoxicological effects of cyclosporin A (CsA) were studied by enhanced histopathological and functional tests in rats. Male F344 rats were orally administered with CsA in doses of 0, 2.5, 10, and 40 mg/kg/day for 28 successive days. Hematological examination revealed that the CsA treatment brought about a marked dose-dependent decrease in the number of WBCs, which was attributed to a decrease in the number of lymphocytes. In the femoral bone marrow, a significant reduction in the number of nucleated cells was observed, which was attributed to a decrease in the number of lymphocytes and erythroblasts. Histopathologically, diminution of thymic medullas, appearance of tangible body macrophages in thymic cortices, and calcification and basophilic changes in kidneys were observed in the middle and high dose groups. Immunohistological examination with anti-rat T lymphocyte antibody showed a decrease in the number of T cells at the periarterial lymphatic sheaths in the spleens. As for the functional tests, CsA treatment remarkably reduced the PFC number even in the low dose group. The Con A response of spleen cells was decreased in the middle and high dose groups. The STM response was reduced only in the high dose group. The NK activity was little affected. Thus, in the CsA-treated F344 rats, the enhanced histopathological and some functional tests which were proposed by ICICIS, were found to be useful to detect damages to the immune system.

Administration, Oral↗