Biomedical subjects

K Ohshima

Publications and source records attributed to K Ohshima.

At least 163 records · Page 9Linked to original sources

PubMed1998

Inhibition of ovarian follicular development associated with a decrease in luteinizing hormone levels during the estrous cycle of the rat.

To examine the importance of tonic LH secretion in ovarian follicular development, plasma concentrations of LH were lowered by administering antiserum to GnRH (GnRH AS). At 1100 h on metestrus or diestrus of the 4-day estrous cycle, rats were injected with GnRH AS, and blood samples were collected at 6 h intervals until 1100 h on the next metestrus. Separately, rats were injected with hCG after the administration of GnRH AS to examine the effect of lowered LH on the number of ovulatory follicles. Treatment with GnRH AS on either metestrus or diestrus lowered plasma concentrations of LH, inhibin, and estradiol. In contrast, the plasma concentrations of FSH increased after the GnRH AS treatment, probably due to a decrease in plasma levels of inhibin associated with suppression of ovarian follicular development. Administration of GnRH AS on metestrus noticeably reduced the number of ovulatory follicles in spite of the high FSH secretion. Such a reduction in the number of ovulatory follicles was blocked by replacing rat LH with ovine LH. These data indicate that tonic secretion of LH plays an important role in the regulation of follicular development during the estrous cycle of the rat.

Animals↗

PubMed1998

Intravascular large cell lymphoma associated with hypoalbuminemia.

We report here a 71-yr-old Japanese woman who presented with severe anasarca and hypoalbuminemia. She had a postmortem diagnosis of intravascular large B-cell lymphoma, which is a rare type of lymphoma characterized by an intravascular proliferation of lymphoma cells. Severe generalized edema was thought to be attributed to vascular and/or lymphatic obstruction due to proliferation of lymphoma cells within the lumina and/or an increase in catabolism induced by tumor proliferation.

Aged↗

PubMed1998

Comparison of coat protein epitopes of two zucchini yellow mosaic virus isolates.

Serological differences between two zucchini yellow mosaic virus (ZYMV) isolates (ZYMV-169 and ZYMV-M) obtained from two distinct geographical locations in Japan were determined by mapping epitopes on the coat proteins (CPs) of the two isolates. A total of 45 monoclonal antibodies (MAbs) against the two isolates were produced and the epitopes on the CPs were delineated by reacting these MAbs with trypsin-treated ZYMV particles and Escherichia coli-expressed ZYMV CP fragments. Six MAbs of groups I-a and I-b, specific for ZYMV-169, recognised two epitopes in the N-terminal region at amino acids (aa) 1-28 and 6-41 of ZYMV-169 CP. Fourteen MAbs of group II, specific for ZYMV-M, recognised epitopes in the N-terminal region of ZYMV-M CP. Twenty-one MAbs of groups III-a, III-b(i), III-b(ii), and III-b(iii), reacting with both isolates, recognised four epitopes; one epitope was located in the N-terminal region at aa 6-28 and the remaining three epitopes were located in the core region at aa 42-95, 171-227 and 228-259 of ZYMV CPs.

Amino Acid Sequence↗

PubMed1997

SINEs and LINEs share common 3' sequences: a review.

There are now five reported examples in which the 3' ends of tRNA-derived SINEs are derived from the 3' ends of LINEs. These examples include representative sequences from turtles, fish, mammals and plants (Ohshima et al., 1996, Mol. Cell. Biol., 16, 3756 3764; Okada and Hamada, 1997, J. Mol. Evol. 44, Suppl 1:S52-S56). In this review, we discuss the generality of this architecture of SINEs, adding new examples of pairs of SINEs and LINEs, which include one complete and two probable examples from this laboratory and one complete example from the laboratory of Arian Smit. This organization of SINEs and LINEs provides the basis for a simple general scheme by which SINEs might acquire retropositional activity.

Amino Acid Sequence↗

PubMed1997

Molecular evidence from retroposons that whales form a clade within even-toed ungulates.

The origin of whales and their transition from terrestrial life to a fully aquatic existence has been studied in depth. Palaeontological, morphological and molecular studies suggest that the order Cetacea (whales, dolphins and porpoises) is more closely related to the order Artiodactyla (even-toed ungulates, including cows, camels and pigs) than to other ungulate orders. The traditional view that the order Artiodactyla is monophyletic has been challenged by molecular analyses of variations in mitochondrial and nuclear DNA. We have characterized two families of short interspersed elements (SINEs) that were present exclusively in the genomes of whales, ruminants and hippopotamuses, but not in those of camels and pigs. We made an extensive survey of retropositional events that might have occurred during the divergence of whales and even-toed ungulates. We have characterized nine retropositional events of a SINE unit, each of which provides phylogenetic resolution of the relationships among whales, ruminants, hippopotamuses and pigs. Our data provide evidence that whales, ruminants and hippopotamuses form a monophyletic group.

Animals↗

PubMed1997

Clonal HTLV-I-infected CD4+ T-lymphocytes and non-clonal non-HTLV-I-infected giant cells in incipient ATLL with Hodgkin-like histologic features.

Lymph nodes from the incipient or early neoplastic phase of adult T-cell leukemia/lymphoma (ATLL) histologically resemble Hodgkin's disease. Integrated proviral human T-lymphotrophic virus type I (HTLV-I) has been demonstrated in such lesions. We studied 18 patients with this disease, and about half of the cases developed typical ATLL within 2 or 3 years. In all cases, either mono- or oligoclonal cell populations with proviral HTLV-I DNA were detected by Southern blot analysis and/or inverse polymerase chain reaction (IPCR). In addition, either a mono- or oligoclonal rearrangement of T-cell receptor genes was demonstrated. Giant cells with Reed-Sternberg-like histological features revealed CD15 and CD30 positivity. The background infiltrating lymphocytes represented either no or only minimal nuclear abnormalities with a CD4+ T-cell phenotype. In less than half of all cases, Epstein-Barr virus (EBV) infected the giant cells. A mixed EBV-A and -B type was found in 3, and a multiple genotype of EBV lymphocyte-determined membrane antigen (LYDMA) was found in 6 cases. These results could have been due to the immunodeficient status of the patients. A single-cell PCR of the giant cell, B cell, CD4+ or CD8+ T cells could be performed after cell sorting in 4 cases. HTLV-I infection was frequently found in the CD4+ T cells, but in neither the giant cells nor the B cells. The CD4+ T cells exhibited clonality. The giant cells showed various PCR products of IgH, and also expressed recombination activating genes (RAG). In summary, the giant cells were reactive cells, which resembled the immature B-lineage cells, while HTLV-I infected the CD4+ T cells, which demonstrated clonality. Based on these above findings, we consider CD4+ cells to play an important role in ATLL tumorigenesis.

Adolescent↗

PubMed1997

Interleukin-10 expression and cytotoxic-T-cell response in Epstein-Barr-virus-associated nasopharyngeal carcinoma.

Interleukin-10 (IL-10) is an inhibitory cytokine produced by various cell types. It exhibits strong sequence homology to BCRF-1 (viral IL-10, vIL-10), an open reading frame in the Epstein-Barr-virus (EBV) genome. Using in situ hybridization (ISH), polymerase chain reaction (PCR) and immunohistochemistry, we checked 41 cases of nasopharyngeal carcinoma (NPC), to study the presence of EBV in the tumor cells, as well as to clarify the relationship between IL-10 expression of the tumor cells and the response of cytotoxic T cells. IL-10 expression was studied by immunohistochemistry; as a result, 29 of 41 cases expressed EBER-1 RNA of EBV by ISH. In addition, 19 of the 29 with EBV and 9 of 12 without EBV cases expressed IL-10 in the tumor cells. The number of cytotoxic T cells increased in the tumor tissue, and the increase in the intratumoral stroma was stronger than in the remaining normal epithelia. The number of cytotoxic T cells also significantly increased in the cases with EBV. On the other hand, in the IL-10-positive series, the number of cytotoxic T cells decreased significantly more than in IL-10-negative series. In view of the established inhibitory effects of IL-10, expression of IL-10 may therefore be one of the mechanisms for NPC cells as well as EBV to counter local immune defense. However, we could not conclude whether or not IL-10 expression was directly induced by EBV.

Adolescent↗

PubMed1997

Flexible DNA: genetically unstable CTG.CAG and CGG.CCG from human hereditary neuromuscular disease genes.

The properties of duplex CTG.CAG and CGG.CCG, which are involved in the etiology of several hereditary neurodegenerative diseases, were investigated by a variety of methods, including circularization kinetics, apparent helical repeat determination, and polyacrylamide gel electrophoresis. The bending moduli were 1.13 x 10(-19) erg.cm for CTG and 1.27 x 10(-19) erg.cm for CGG, approximately 40% less than for random B-DNA. Also, the persistence lengths of the triplet repeat sequences were approximately 60% the value for random B-DNA. However, the torsional moduli and the helical repeats were 2.3 x 10(-19) erg.cm and 10.4 base pairs (bp)/turn for CTG and 2.4 x 10(-19) erg.cm and 10.3 bp/turn for CGG, respectively, all within the range for random B-DNA. Determination of the apparent helical repeat by the band shift assay indicated that the writhe of the repeats was different from that of random B-DNA. In addition, molecules of 224-245 bp in length (64-71 triplet repeats) were able to form topological isomers upon cyclization. The low bending moduli are consistent with predictions from crystallographic variations in slide, roll, and tilt. No unpaired bases or non-B-DNA structures could be detected by chemical and enzymatic probe analyses, two-dimensional agarose gel electrophoresis, and immunological studies. Hence, CTG and CGG are more flexible and highly writhed than random B-DNA and thus would be expected to act as sinks for the accumulation of superhelical density.

DNA↗

PubMed1997

Hairpin formation during DNA synthesis primer realignment in vitro in triplet repeat sequences from human hereditary disease genes.

Genetic expansion of DNA triplet repeat sequences (TRS) found in neurogenetic disorders may be due to abnormal DNA replication. We have previously observed strong DNA synthesis pausings at specific loci within the long tracts (> approximately 70 repeats) of CTG.CAG and CGG.CCG as well as GTC.GAC by primer extensions in vitro using DNA polymerases (the Klenow fragment of Escherichia coli DNA polymerase I, the modified T7 DNA polymerase (Sequenase), and human DNA polymerase beta). Herein, we have isolated and analyzed the products of stalled synthesis found at approximately 30-40 triplets from the beginning of the TRS. DNA sequence analyses revealed that the stalled products contained short tracts of homogeneous TRS (6-12 repeats) in the middle of the sequence corresponding to the flanking region of the primer-template sequence. The sequence at the 3'-side terminated at the end of the primer, indicating that the primer molecule had served as a template. In addition, chemical probe and polyacrylamide gel electrophoretic analyses revealed that the stalled products existed in hairpin structures. We postulate that these products of the DNA polymerases are caused by the existence of an unusual DNA conformation(s) within the TRS, during the in vitro DNA synthesis, enhancing the DNA slippages and the hairpin formations in the TRS due to primer realignment. The consequence of these steps is DNA synthesis to the end of the primer and termination. Primer realignment including hairpin formation may play an important intermediate role in the replication of TRS in vivo to elicit genetic expansions.

Betaine↗

PubMed1997

Increased expression of low density lipoprotein receptor-related protein/alpha2-macroglobulin receptor in human malignant astrocytomas.

Low-density lipoprotein receptor-related protein (LRP) plays an important role in regulating proteinase activity, which is necessary for cellular invasive processes. In this study, we investigated the presence of both LRP and urokinase-type plasminogen activator receptor (uPAR) in astrocytoma tissues and in glioma cell lines by PCR and immunohistochemical analysis. LRP mRNA was expressed frequently in glioblastomas, as compared with low-grade astrocytomas by PCR analysis and was well correlated with uPAR expression. These results were consistent with the immunohistochemical localization of LRP in glioblastomas. Immunohistochemistry of LRP on sequential frozen sections showed that neoplastic glial cells and endothelial cells of glioblastomas exhibited intense LRP immunoreactivity, whereas LRP was almost undetectable in low-grade astrocytomas and in normal glial cells and endothelial cells of normal brain tissues. In normal brain tissues, LRP immunoreactivity was identified in the pyramidal neurons of the cerebral cortex. In metastatic brain tumors (metastatic lung adenocarcinomas) and primary lung adenocarcinomas, LRP expression was low to undetectable, suggesting that LRP expression is regulated differently in these tumors than in malignant astrocytomas. These results indicate that LRP is overexpressed in malignant astrocytomas, especially in glioblastomas, and the increased expression of LRP appears to correlate with the expression of uPAR and the malignancy of astrocytomas. Our results suggest strongly that LRP may play a role in facilitating glioblastoma invasiveness and neovascularization within tumor tissues by regulating cell surface proteolytic activity.

Adenocarcinoma↗

PubMed1997

Integrated Epstein-Barr virus (EBV) and chromosomal abnormality in chronic active EBV infection.

In order to examine the role of Epstein-Barr virus (EBV) in the pathogenesis of chronic active EBV infection (CAEBV), we investigated whether or not EBV integration into the human genome is associated with any chromosonal abnormality. We therefore analyzed 4 cases of CAEBV: 2 cases showed a normal karyotype, while one had an oligo-clonal 6th chromosomal abnormality and the fourth had a clonal 6th deletion (q15q23). In addition, the case with an oligo-clonal abnormality also had oligo-clonal EBV terminal repeat (TR) bands, while the case with a clonal abnormality showed a clonal TR band. In contrast, the 2 cases with a normal karyotype showed no clonal band. Two-color fluorescence in situ hybridization (FISH) was used to detect the integrated EBV and the 6th chromosomal site. The presence of integrated EBV into the 6th chromosome was not frequent in the 2 cases with a normal karyotype, but it was statistically frequent in the case with an oligo-clonal 6th abnormality. In the case with a clonal 6th deletion, integration in the 6th chromosome was also slightly higher than that in the other chromosomes. In CAEBV, integrated EBV might thus be associated both with chromosomal abnormality and with pathogenesis.

Chromosome Aberrations↗

PubMed1997

Regulation by interleukin-10 and interleukin-4 of cyclooxygenase-2 expression in human neutrophils.

Neutrophils are important effector cells of acute inflammation because of their potential capacity to synthesize various proinflammatory mediators, and inhibition of their production is expected to result in anti-inflammatory effects. In this study, we investigate the effects of the anti-inflammatory cytokines, interleukin-10 (IL-10) and IL-4, on prostanoid synthesis in human neutrophils. Neutrophils isolated from healthy donors constitutively produced a small amount of prostaglandin E2 (PGE2) without any stimulations, whereas they produced a large amount of PGE2 after lipopolysaccharide (LPS) stimulation. IL-10 and IL-4 selectively inhibited their LPS-induced PGE2 production. Inhibition by both cytokines occurred at an early stage of LPS stimulation. Anti-IL-10 treatment of LPS-stimulated neutrophils resulted in enhanced PGE2 production. LPS-induced PGE2 and thromboxane B2 (TXB2) production in aspirin-treated neutrophils was significantly inhibited by IL-10, IL-4, and NS-398. Moreover, IL-10 and IL-4 inhibited LPS-induced cyclooxygenase (COX) activity in neutrophils. Western blot and immunocytochemical analysis showed that COX-2 protein was clearly induced in LPS-stimulated neutrophils and that its induction was inhibited by both IL-10 and IL-4. Moreover, both of these cytokines inhibited COX-2 mRNA expression in LPS-stimulated neutrophils. These results raise the possibility that these two cytokines may both offer potent clinical utility as anti-inflammatory agents in the future.

Cells, Cultured↗

PubMed1997

Clonal integration and expression of human T-cell lymphotropic virus type I in carriers detected by polymerase chain reaction and inverse PCR.

Adult T-cell leukemia (ATL) is a neoplasm of mature helper (CD4) T lymphocytes, and human T-cell lymphotropic virus type-I (HTLV-I) has been suggested to be the causative virus of ATL. HTLV-I integrates its proviruses into random sites in host chromosomal DNA. Clonal integration has been observed in patients with ATL, including smoldering, chronic, and acute states. However, random and/or polyclonal integration has only been reported in a few asymptomatic HTLV-I carriers. To clarify the clonality of HTLV-I-infected cells in carriers, we used an inverse polymerase chain reaction (IPCR), which is more sensitive than Southern blot analysis. We used the peripheral blood momonuclear cells (PBMC) from 16 asymptomatic carriers and the separated CD4-positive cells. No cases showed either a monoclonal or polyclonal integration of the HTLV-I provirus by Southern blot. But, using IPCR, 7 of 16 cases showed either mono- or oligoclonal integration. In addition, the populations of clonal provirus in the total PBMC were frequently different from those in the CD4-positive cells. Three cases showed expression of HTLV-I tax/rex mRNA in the total PBMC, but no such expression was found in CD4-positive cells. In this study, an unexpected frequency of clonal HTLV-I provirus DNA was observed in HTLV-I carriers. These findings indicate that the clonal but nonmalignant proliferation of HTLV-I-infected cells already occurs even in HTLV-I carriers, and therefore that some other step is necessary to induce malignant proliferation.

Adolescent↗

PubMed1997

Terminal deoxynucleotidyl transferase staining of malignant lymphomas in paraffin sections: a useful method for the diagnosis of lymphoblastic lymphoma.

Terminal deoxynucleotidyl transferase (TdT) is a DNA polymerase located in the cell nucleus which catalyses the polymerization of deoxynucleotides at the 3'hydroxyl ends of oligo- or polydeoxynucleotide initiators without a template. TdT is known as a useful marker for the diagnosis of acute lymphoblastic leukaemia/lymphoma, but its detection usually requires fresh tissue specimens or cell suspensions, using either an enzyme analysis or immuno-fluorescence or -peroxidase staining. Until the recent development of the use of microwave-treated paraffin sections for immunoperoxidase staining, detection of TdT in paraffin sections required rather complicated processes. This new simple technique was applied to paraffin sections from the tumour tissue specimens of 16 patients with lymphoblastic lymphoma and of seven patients with non-endemic Burkitt's lymphoma, which is sometimes difficult to differentiate from lymphoblastic lymphoma because of their similar clinicopathological characteristics. In addition, as a control, ten cases each were examined of adult T-cell leukaemia/lymphoma (ATLL) and angioimmunoblastic lymphoma (AILD), which are both peripheral T-cell lymphomas. The tumour cells from 15 of the 16 (94 per cent) patients with lymphoblastic lymphoma were found to be TdT-positive. The specificity of the anti-TdT antibody used was confirmed by immunoblot and the specific 60 kD band was detected only in a specimen of lymphoblastic lymphoma. These results show that the immunostaining of TdT on paraffin-embedded sections is a useful method for differentiating lymphoblastic lymphoma from other lymphomas. This method is applicable to a routine diagnostic service.

Adolescent↗

PubMed1997

Pancreatic tumor formed by infiltration of adult T-cell leukemia cells.

CONCLUSION: We have described a case of pancreatic tumor formed by adult T-cell leukemia (ATL) cell infiltration. BACKGROUND: The patient was diagnosed as chronic ATL hematologically with the findings of increased number of atypical lymphocytes, ATL cells in the peripheral blood, and positive human T-cell leukemia virus type I (HTLV-I) antibody in the serum. The pancreatic tumor was identified by ultrasonography and computed tomography as a diffusely swollen tumor from the body to the tail of the pancreas. Biopsy specimen confirmed the ATL cell infiltration into the pancreas immunohistochemically, and Southern blot analysis showed the integration of HTLV-I proviral DNA both in the pancreas and in the peripheral blood. RESULTS: The pancreatic tumor diminished spontaneously without chemotherapy when ATL cells in the peripheral blood disappeared by spontaneous regression.

Aged↗

PubMed1997

T-stem cell leukemia/lymphoma with both myeloid lineage conversion and T-specific delta recombination.

We evaluated retrospectively the clinical and biological characteristics of six patients with CD7+ early T-acute lymphoblastic leukemia and lymphoma (T-ALL/LBL) originating from prothymocyte stage I (pro-T I) or II cells. Patients exhibited mediastinal mass (five of six) and lymphoadenopathy (five of six) but without leukocytosis and circulating blast cells (six of six). All patients achieved a complete remission. All but one had a relapse with a transformation to the mixed type (triphenotype--three cases, biphenotype-two cases) including myeloid features in three patients. The altered phenotypes were myeloperoxidase (MPO)+ (three of five), CD13+ (four of five), CD33+ (three of five) and CD19+ (three of five). The difference for MPO-positivity were observed between the bone marrow (BM)- and lymph node (LN)-blast cells (three of three). On cytogenetic analysis, there is no common abnormality in these patients. Immunomolecular analysis revealed T-cell lineage specific delta gene rearrangements [D delta 2-J delta 1 (five of six) and V delta 1-J delta 1 (one of six)] in all cases. Furthermore, D delta 2-J delta 1 occurred even in the cases with the pro-T I phenotype. Rearrangements of TCR beta, gamma or immunoglobulin heavy chain genes occurred in three patients. The same rearranged band(s) appeared at both diagnosis and relapse, indicating the same originality of the pro-T leukemic cell clone (three of three). We suggest that this type of CD7+ early T-ALL/LBL was transformed from a pro-T I or II cell, such as T-stem cell leukemia/lymphoma, which is a subtype of CD7+ stem cell leukemia as defined by Kurtzberg et al. This study reveals that pro-T I and II cells might be capable of myeloid, T- and B-lymphoid differentiation, and T-cell lineage specific TCR delta recombination occurs.

Adult↗

PubMed1997

Heterogeneity of systemic extra-nodal Epstein-Barr virus-associated lympho-histiocytic tumor--ten autopsy cases of human immunodeficiency virus-negative Japanese.

Epstein-Barr virus associated T-Cell lymphoma mimicking malignant histiocytosis (MH) has been previously reported. We selected 10 autopsy cases of extranodal lymphoma or histiocytic tumor, which showed an EBV presence in the tumor cells as well as a fulminant clinical course. The detailed clinicopathologic features were thus clarified. A retrospective study was performed on ten adult patients, eight males and two females, and almost all cases presented with a fulminant clinical course, revealing pancytopenia, liver dysfunction and disseminated intravascular coagulopathy. Immunophenotypic and genotypic studies along with in situ hybridization (ISH) were performed. The autopsy findings mainly showed extra nodal involvement in the liver (10 patients), spleen (9 patients), intestinal tract (5 patients), bone marrow (5 patients), nasal cavity, lungs, adrenal glands, kidneys (2 patients) and brain. Histologically atypical pleomorphic lymphoid cells were observed to infiltrate with reactive histiocytes, some of which showed hemophagocytosis. Based on the histological and clinical findings, diagnosis of malignant histiocytosis was made. ISH showed an EBV-presence in almost all the tumor cells. The immunophenotype and/or genotype studies demonstrated T-cell lymphoma (2 patients), Histiocytic tumors (2 patients), B-cell lymphoma (1 patients), natural killer (NK) cell lymphoma (3 patients), and T/NK lymphoma (2 patients), in which T or NK could not be confirmed, due to a lack of fresh materials. Based on the above findings, the histological appearance of EBV-associated MH previously defined was shown to be common to extra-nodal malignant lymphomas having origin in various organs, although the cytological and genetic features were heterogenous.

Adolescent↗

PubMed1997

Parvovirus B19-associated haemophagocytic syndrome with lymphadenopathy resembling histiocytic necrotizing lymphadenitis (Kikuchi's disease).

A 15-year-old girl developed a haemophagocytic syndrome caused by human parvovirus B19 (PVB19). The cervical lymph node histology, resembling that of histiocytic necrotizing lymphadenitis (HNL, Kikuchi's disease), included several transformed lymphocytes, numerous histocytes, and massive necrosis. We detected PVB19-positive cells in the lymph node by immunohistochemistry. Possible autoimmune mechanisms in HNL-like diseases triggered by PVB19 are discussed.

Adolescent↗