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Biomedical subjects

Y Uematsu

Publications and source records attributed to Y Uematsu.

At least 73 records · Page 4Linked to original sources
PubMed1991

Hepatocellular carcinoma with tumor thrombus extending into the right atrium: report of a successful resection with the use of cardiopulmonary bypass.

Hepatocellular carcinoma with a tumor thrombus extending into the right atrium has been considered beyond the reach of resection. These patients usually die within a short period because of pulmonary embolism, heart failure, or cancer progression. The only treatment is hepatic resection with removal of the tumor thrombus. A 38-year-old woman underwent left lobectomy with removal of the tumor thrombus with the use of cardiopulmonary bypass. The patient had an uneventful course and is doing well 15 months after surgery, without signs of recurrence. We have proved that hepatic resection with removal of a tumor thrombus extending into the right atrium can be carried out successfully. The next problem is whether the lives of these patients can be prolonged by this operation.

Adult↗
PubMed1990

Epithelial cysts in the central nervous system, characteristic expression of cytokeratins in an immunohistochemical study.

Nineteen epithelial cysts in the central nervous system including six colloid cysts of the third ventricle, seven Rathke's cleft cysts in the sella, two enterogenous cysts in the posterior fossa, two epithelial cysts in the spinal canal and two neuroectodermal cysts in the cerebrum were examined immunohistochemically for expression of intermediate filament proteins-simple type, stratified type and skin type cytokeratins and GFAP. Colloid cysts of the third ventricle, Rathke's cleft cysts in the sella and epithelial cysts in the spinal canal expressed complex type cytokeratins while enterogenous cysts and neuro-ectodermal cysts showed only simple type cytokeratins. In addition, Rathke's cleft cysts expressed GFAP in occasional lining cells. The characteristic composition and distribution of cytokeratins in various kinds of epithelial cysts in the central nervous system are demonstrated and discussed with regard to their origins.

Adult↗
PubMed1990

[Epithelial cyst in the central nervous system--characteristic expression of cytokeratin].

Twenty one cases of epithelial cysts in the central nervous system including six colloid cysts of the third ventricle, eight Rathke's cleft cysts in the sella, two enterogenous cysts in the posterior fossa, two epithelial cysts in the spinal canal and three neuroectodermal cysts in the cerebrum were examined immunohistochemically for expression of intermediate filamentous proteins-simple type, stratified type and skin type cytokeratins and GFAP. Colloid cysts of the third ventricle. Rathke's cleft cysts in the sella and epithelial cysts in the spinal canal expressed complexed type cytokeratins while enterogenous cysts and neuroectodermal cysts showed only simple type cytokeratins. In addition, several Rathke's cleft cysts demonstrated skin type differentiation and expressed GFAP in occasional lining cells. The characteristic composition and distribution of cytokeratins in various kinds of epithelial cysts in the central nervous system are demonstrated and discussed with regards to their origins.

Adult↗
PubMed1989

Distribution of epithelial membrane antigen in normal and neoplastic human ependyma.

The ependyma and choroid plexus of 23 normal brains and 20 ependymal tumors were examined immunohistochemically for expression of epithelial membrane antigen (EMA) using a specific monoclonal antibody. The ependyma of normal brains showed three patterns of immunoreactivity: membrane immunoreactivity confined to the luminal surface; irregular punctate intracytoplasmic immunoreactivity in the subependymal layer; and spherical and ring-like intracytoplasmic immunoreactivity in the subependymal layer. Of 13 differentiated ependymomas 11 reflected the immunoreactive patterns of normal ependyma. The anaplastic ependymomas and ependymoblastomas had no immunoreactivity. Our results indicate that EMA has a highly selective distribution in the ependyma, and is a marker for differentiated ependymoma.

Adult↗
PubMed1989

Gross genetic differences among substrains of NZB mice.

Substrains of NZB mice have been compared by Southern blot analysis using several probes. The restriction fragment length polymorphism of probes derived from the Igh-V, Igk-V, Tcr alpha-C loci and of the long terminal repeat of the mouse mammary tumour virus revealed that NZB/BlLwPtIbm were grossly different from NZB/BlNJ and NZB/BlOla. Comparison with mouse strains of the Igk-V haplotypes a and d suggested that NZB/BlLwPtIbm contain genetic material of the C58 mouse strain.

Animals↗
PubMed1989

Transgenic mice to study T-cell receptor gene regulation and repertoire formation.

Transgenic mice have been obtained with genes coding for an alpha beta T-cell receptor that recognizes the male-specific antigen H-Y in association with the Db class I major histocompatibility complex molecule. Most if not all of the T-cells express the beta chain encoded by the transgene and show allelic exclusion of endogenous beta genes. In contrast, the expression of the alpha transgene does not completely block rearrangement and formation of functional endogenous alpha genes. In H-2b transgenic female mice the transgenic T-cell receptor is functionally expressed on at least 30% of CD8+ peripheral T-lymphocytes as indicated by their ability to lyse male target cells. Also in transgenic H-2b male mice a large proportion of peripheral T-cells appear to express the transgenic receptor. However, these cells do not react with male target cells because they show only low level or no expression of CD8 cell interaction molecules. Tolerance is established in the male transgenic thymus through deletion of CD4+CD8+ immature thymocytes.

Animals↗
PubMed1989

[The astrocyte-endothelial interface in cerebellar astrocytoma].

The astrocyte-endothelial interface is a component of the anatomical blood-brain barrier in the central nervous system and is of interest in neoplastic lesions. We, therefore, investigated the fine structure of this interface in five, well-differentiated cerebellar astrocytomas. The astrocyte-endothelial interface in cerebellar astrocytomas revealed various abnormalities. The perivascular space is usually wide and contains various amounts of collagen fibers, fibroblasts and pericytes. The basal lamina of the endothelial cell is mostly single-layered and continuous, but sometimes multilayered and discontinuous. The basal lamina of the neoplastic astrocytic cell is usually single-layered and continuous, but is occasionally absent in foci. The basal lamina of the endothelial cell is more prominent than that of the astrocyte. The neoplastic astrocyte has not so well developed cell junctions and poorly formed peripheral expansions of the processes. The relationship between the basal lamina of the endothelial cell and that of the astrocyte in cerebellar astrocytomas is compared to that in ependymomas.

Adult↗
PubMed1989

[A case of pseudotumor cerebri associated with colon cancer].

A case of pseudotumor cerebri associated with iron deficiency anemia due to colon cancer is reported in a 37-year-old woman. Her initial symptoms were vomiting and severe headache. On physical examination, no lymph nodes and abdominal mass were palpable but marked anemia was noted in her skin and conjunctiva . Neurological examination revealed papilledema in her both eyes and stiff neck. There was no abnormal findings on CT scan on admission. Spinal puncture revealed CSF pressure as high as 620 mmH2O with normal cells, protein, sugar and chloride levels. Hematological examination revealed iron deficiency anemia and thrombocytosis. Angiography at third day revealed no sinus occlusion, but retention of contrast media was seen on the cortical vein of parietal lobe and right transverse sinus. Brain scintigram at sixth day revealed mild accumulation in left parietal lobe, so small venous infarction was suggested. There were two circumscribed stenotic lesions of right ascending colon in the barium enema, and right hemicolectomy was achieved. The pathological diagnosis was adenocarcinoma. The symptoms of pseudotumor cerebri was completely disappeared soon after the surgery together with resolution of anemia. She lives with no deficits now 1 year 3 months after surgery. In conclusion much attention is necessary to a patient of pseudotumor cerebri with iron deficiency anemia for the presence of cancer, because not only this central nervous system lesion is reversible and curable but also the cancer itself may be curable by surgery.

Adenocarcinoma↗
PubMed1988

Thymic major histocompatibility complex antigens and the alpha beta T-cell receptor determine the CD4/CD8 phenotype of T cells.

T-cell receptors and T-cell subsets were analysed in T-cell receptor transgenic mice expressing alpha and beta T-cell receptor genes isolated from a male-specific, H-2Db-restricted CD4-8+ T-cell clone. The results indicate that the specific interaction of the T-cell receptor on immature thymocytes with thymic major histocompatibility complex antigens determines the differentiation of CD4+8+ thymocytes into either CD4+8- or CD4-8+ mature T cells.

Animals↗
PubMed1988

T-cell-specific deletion of T-cell receptor transgenes allows functional rearrangement of endogenous alpha- and beta-genes.

In B cells the loci encoding immunoglobulin chains usually show allelic exclusion; a given B cell transcribes and translates only one productively rearranged allele of the heavy and light chain loci. This ensures that each B cell expresses only one antigen receptor. The loci encoding T-cell receptor (TCR) alpha- and beta-genes may behave similarly. We have previously reported that the expression of a transgenic TCR beta-chain prevents functional and nonfunctional V beta rearrangements in the endogenous beta-chain loci but not D beta J beta rearrangements. We have also been unable to detect the expression of the TCR gamma-chain locus in thymocytes of these mice (unpublished observations). To study the mechanisms involved in forming a mature T-cell repertoire further, we have constructed mice expressing alpha- and beta-TCR transgenes derived from a cytotoxic T-cell clone that is specific for the male antigen H-Y in the context of H-2Db MHC molecules. Here we show that in these mice rearrangement of endogenous alpha-chain loci is also suppressed, although to a lesser extent than rearrangement of beta-chain loci. In addition, in male alpha beta TCR transgenic mice we observed T-cell clones which had deleted both transgenic alpha- and beta-chain genes and expressed endogenous alpha- and beta-chain TCR genes. These cells are presumably derived from rare thymocytes that leave the male thymus because their TCR no longer recognizes self antigen. The vast majority of CD4+8+ nonmature thymocytes expressing alpha- and beta-transgenes are deleted in the male thymus.

Animals↗
PubMed1988

In transgenic mice the introduced functional T cell receptor beta gene prevents expression of endogenous beta genes.

Transgenic mice were constructed with a functional T cell receptor beta gene. Transcription of the introduced gene is largely confined to T cells, but low levels of transcripts are also seen in B cells and in other tissues. Serological analyses show that most, if not all, of the T lymphocytes express the transgenic beta chain on the cell surface and lack beta chains encoded by endogenous beta genes. Molecular genetic analyses of uncloned and cloned T lymphocytes demonstrate that rearrangement of endogenous beta genes is incomplete. Partial D beta 1-J beta 1 rearrangements are found preferentially, while complete VDJ rearrangements are not seen. These findings show that expression of the transgene regulates the rearrangement of endogenous beta genes. Although the alpha beta T cell receptors of the transgenic mice are homogeneous with respect to the beta chain, they are fully functional, at least in a variety of allogeneic responses.

Animals↗
PubMed1988

Transcription of T cell receptor beta-chain genes is controlled by a downstream regulatory element.

To characterize cis-acting elements controlling the expression of T cell receptor beta-chains we generated a number of transgenic mouse lines harboring a rearranged T cell receptor beta-chain with different extensions of 5' and 3' flanking sequences. Transcriptional analysis of transgenic mice carrying these clones showed that sequences located downstream of the polyadenylation signal of the C beta 2 region are indispensable for expression in transgenic mice. The sequences conferring enhancer activity in this fragment were further defined by transient CAT assays. Strong enhancer activity was found to reside in a 550 bp fragment located 5 kb downstream from C beta 2. The nucleotide sequence of this fragment revealed a number of oligonucleotide motifs characteristic for enhancer elements.

Animals↗
PubMed1988

The same MHC recombinational hot spots are active in crossing-over between wild/wild and wild/inbred mouse chromosomes.

Four recombinational breakpoints were mapped in the K-A interval of the mouse major histocompatibility complex (MHC) by Southern blot analysis. The breakpoint in B10.SBR, containing a b/s recombinant MHC haplotype, is located about 45 kb upstream of the A beta 2 gene close to the breakpoint in B10.AQR. Crossover in two cas3/cas4 and one cas4/cas3 recombinant haplotypes has taken place in the previously identified K/A beta 3 and A beta 3/A beta 2 recombinational hot spots. The same hot spots are thus active in crossover between two Mus musculus castaneus MHC haplotypes and in crossover between a laboratory and a M. m. castaneus MHC haplotype.

Animals↗
PubMed1988

Pineoblastoma with an unusually long survival. Case report.

The authors report a case of pineoblastoma with a 9-year follow-up period after stereotaxic biopsy, a shunting procedure, and radiotherapy. Light and electron microscopic studies of biopsy and autopsy specimens revealed no cell differentiation of the pineoblastoma. The possible factors predisposing to long survival are discussed in comparison with the course in patients with medulloblastoma.

Adult↗