Search PubMed⌕ Search

Biomedical subjects

T Nitta

Publications and source records attributed to T Nitta.

At least 127 records · Page 7Linked to original sources
PubMed1992

Recovery functions of somatosensory evoked potentials in parkinsonian patients.

The aim of this study was to analyze the recovery functions of median nerve somatosensory evoked potentials (SEPs) and to clarify changes in the somatosensory system of patients with Parkinson's disease (PD). The central and frontal SEPs and the nerve potential of the median nerve were examined. The latencies and amplitudes of SEPs produced by a single shock in patients with PD were normal. The recovery functions of central SEPs showed a low degree of suppression in patients with PD, although the recovery curve of the nerve potential in PD patients was almost normal. The change in recovery curves of SEPs in patients with sensory complaints were more noticeable than that in patients without sensory disturbance. A low degree of suppression of central SEPs might play a role in the sensory complaints of PD patients.

Adult↗
PubMed1992

Lysosomal enzymic activity of astroglial cells.

Using human and rat Glioma cell lines and mouse astrocytes prepared from newborn mice, lysosomal enzymatic activity, which is closely related with phagocytic activity, was assayed by spectrophotometric measurement of p-nitrophenol liberated from the relevant substrate. Lysosomal N-acetyl-beta-D-glucosaminidase and acid phosphatase activity was detected in neoplastic astrocytes at a level of enzymatic activity equal to that of monocyte/macrophage cell lines in certain glioma cells. From the implication of this data, it is suspected that astrocytes may function as phagocytic cells at inflammatory brain lesions.

Acetylglucosaminidase↗
PubMed1992

Expression of Fc gamma receptors on astroglial cell lines and their role in the central nervous system.

Astrocytes have been regarded as the matrix of the central nervous system and as nutritional, metabolic support to neurons. Recently, immunological roles of astrocytes have been reported, especially in multiple sclerosis and experimental allergic encephalitis. One observation shows that human glioma cells, which lack CD4 molecules, can be infected with human immunodeficiency virus in vitro. Another report described that human macrophages can be infected with human immunodeficiency virus through Fc gamma receptors expressed on their cell surfaces. These results prompted us to examine the functioning molecules, especially Fc gamma receptor for immunoglobulin G, expressed on the astroglial cell line. From erythrocyte-antibody rosette assays, redirected cytolysis and flow cytometric analysis, we have shown that human astrocytoma cell lines possess Fc gamma receptors on their cell surfaces. Furthermore, primary cultured murine astrocytes express Fc gamma II receptors, reacting with 2.4G2 monoclonal antibody. Surprisingly, murine astrocytes prepared from newborn BALB/c mice demonstrate killing activity against allogeneic T cell leukemia by antibody-dependent cellular cytotoxicity. After treatment with the macrophage activating factor, interferon-gamma, expression of Fc gamma receptors and killer activity of astrocytes were augmented. From these results, it is suspected that the astroglial cell lines play an important immunological role in the brain.

Animals↗
PubMed1992

[T-cell receptor repertoire in tumor infiltrating lymphocytes within malignant brain tumors].

Expression of T cell receptor (TCR) V alpha and V beta genes in tumor infiltrating lymphocytes (TILs) within human malignant brain tumor was examined. Primers for 18 different human TCR V alpha and 21 V beta families were used to analyze TCRV-(D)-J-C gene rearrangements in TILs in 8 human malignant glioma specimens obtained at surgery. Using the polymerase chain reaction (PCR) method, we detected limited TCR variable region, V alpha gene expression in malignant glial tumors and also V alpha 7 and V alpha 12 TCR genes were preferentially expressed. Usage of TCR V beta gene was not as restricted as in TCR V alpha. These TILs expressing a limited repertoire of TCRs might be isolated, expanded, and used therapeutically for treatment of malignant brain tumors.

Adolescent↗
PubMed1992

[A case of idiopathic ventricular tachycardia with ventricular fibrillation successfully treated with cryoablations and implantable cardioverter defibrillator].

A 16-year-old girl with medically refractory idiopathic ventricular tachycardia (VT) with ventricular fibrillation (VF) underwent cryoablations of the VT origin and received implantable cardioverter defibrillator (ICD). Intraoperative epicardial and endocardial mapping demonstrated the earliest activation site of VT in the infundibular septum of right ventricle. Cryoablations were applied through a pulmonary arteriotomy under mild hypothermic cardiopulmonary bypass with the heart beating. Because of the episodes of VF. ICD implantation was followed. Her postoperative course was uneventful and she remains free from VT and VF.

Adolescent↗
PubMed1992

[Inhibition of c-sis protein synthesis and cell growth with antisense oligonucleotides in human glioma cells].

The protein encoded by the proto-oncogene c-sis is over-amplified in human neuroglial tumors and has been hypothesized as playing an important role in tumorigenesis, but this hypothesis remains to be clarified. In order to address this issue, we examined the effect of 18-bp oligodeoxynucleotides complementary to the sense mRNA of c-sis upon glioma cell growth. First, we investigated the expression of c-sis protooncogenes within cultured human glioma cell lines and also fresh glioma specimens by using polymerase chain reaction. We could detect mRNA transcripts of c-sis in 3 out of 4 glioma cell lines (U138MG, U251MG and A172) and two in 5 glioblastoma multiforme specimens. The antisense oligonucleotides complementary to c-sis mRNA were efficiently incorporated into A172 in vitro and the kinetic study showed that maximum uptake occurred after 48 hours of incubation with antisense oligomers. Exposure of human glioma cell lines to antisense oligodeoxynucleotides targeted against first initiation codon inhibited cell proliferation in a time and dose dependent fashion. From the flow cytometric analysis using anti-c-sis sera, it was demonstrated that the antisense oligomers specifically block the de novo synthesis of intracellular c-sis protein by glioma cells dose-dependently. In contrast to this, the corresponding sense oligomers inhibited neither synthesis of c-sis protein nor glioma cell growth. Taken together, these results clearly support a role of c-sis protein in the proliferation process and show that inducible protein expression can be blocked by means of synthetic oligonucleotides complementary to a coding exon.

Brain Neoplasms↗
PubMed1992

[An analysis of lymphokine gene expression within astrocytoma].

Expression of the lymphokine genes in human astroglial cell lineage was studied. Primers for 9 different human lymphokines, from IL-1 alpha to IL-8, were used to analyze RNA transcripts in 5 cultured human astrocytoma, one neuroblastoma cell line and 4 fresh brain specimens by polymerase chain reaction (PCR). mRNA transcripts of neither IL-1 nor IL-3, the biological activities of which were observed in rat primary cultured astrocytes, could be detected within these cell lines. Two out of 5 unstimulated astrocytomas, U138 and U373, expressed IL-6 genes. IL-8 gene was detected within U87, U138, U251, U373 glioma cells. After stimulation with IL-1 beta, all astrocytoma and one neuroblastoma cell line expressed IL-6 and IL-8 genes. In addition to the cultured cells, we examined IL-6 and IL-8 gene expression within human malignant astrocytoma specimens. The result shows that three out of four glioma specimens expressed IL-6 and IL-8 genes. From these results, it is suspected that astroglial cell-derived IL-6 or IL-8 may participate in local immune reactions accompanying infection, degeneration and malignancies in the central nervous system.

Astrocytoma↗
PubMed1991

An analysis of T-cell-receptor variable-region genes in tumor-infiltrating lymphocytes within malignant tumors.

Expression of T-cell-receptor (TCR) V alpha and V beta genes in tumor-infiltrating lymphocytes (TILs) of 29 patients, 15 melanomas and 14 malignant glial tumors (glioma and medulloblastoma), was investigated. The identification and propagation of T cells with anti-tumor reactivity is crucial to the understanding of the human immune response to tumors, which may possibly be useful in the successful implementation of adoptive immunotherapy against cancer. Despite clinical evidence that a more favorable prognosis is associated with the degree of lymphocyte infiltration within a tumor, the actual role of TIL remains uncertain. In order to address this question, we examined the diversity of the RNA transcripts of TCR genes in TILs within 29 specimens obtained at surgery. Using the polymerase-chain-reaction (PCR) method and primers for 18 different human TCR V alpha and 21 V beta families to analyze TCR V-(D)-J-C gene rearrangements, we detected a limited expression of TCR variable-region V alpha genes of TILs. TCR V beta gene rearrangements were more diverse than those for V alpha. In addition to restricted usage of TCR V alpha genes, preferential expression of V alpha 7 genes was found in 20 out of 29 cases (69%). Predominant usage of V alpha 7 genes was more remarkable in melanoma TILs (14/15) than in glial tumor TILs (6/14). These findings were also confirmed by Southern blot analysis with oligonucleotide probes for the constant (C) region of TCR alpha and beta chains. We suspect that some specific T-cell populations may be directed to antigenic determinants in melanoma cells.

Base Sequence↗
PubMed1991

T-cell receptor V beta gene expression differs in tumor-infiltrating lymphocytes within primary and metastatic melanoma.

Expression of T-cell receptor (TCR) gene rearrangements in tumor-infiltrating lymphocytes (TILs) within primary and metastatic melanoma specimens was studied. In order to analyze TCR gene transcription in TILs within these tissues, we analyzed reverse transcribed complementary DNA from mRNA directly from tissues using the polymerase chain reaction. The polymerase chain reaction-amplified products were confirmed by dot or Southern blot hybridization with C alpha or C beta oligoprobes. First, we investigated the diversity of TCR V alpha and V beta gene usage in human malignant melanoma patients with multiple metastasis. We found in one patient, bearing multiple skin lesions, that the patterns of TCR V alpha and V beta repertoires in different sites of the skin (leg and chest wall) were almost the same. However, in another patient with skin and brain melanomas, different TCR repertoires were presented. Next, we examined the usage of murine TCR V beta genes in TILs within the primary and metastatic sites (liver, lung, and brain) of C57BL/6 mice bearing B16-F10 murine melanoma. The population of TILs in each primary and metastatic site expressed from one to four TCR V beta genes. In each metastatic site, the profile of TCR V beta gene expression was different. A different TCR V beta usage in TILs distributed within metastases of various organs may reflect differences in tumor antigenicity at these sites or may be due to differential homing patterns to these tumors.

Animals↗
PubMed1991

[Dopaminergic control of gonadotropin secretion in male senescence].

To verify the role of the dopaminergic mechanism in the control of gonadotropin secretion and aging of this mechanism in men, we studied serum gonadotropin response to LH-RH (100 micrograms i.v.) in basal condition and during dopamine infusion (DA 4 micrograms/kg/min). Seven young males (24-29yr.) and twenty aged males (50-80yr.) without endocrinological diseases were included in the present study. Aged male subjects were divided into hyperresponders, in whom maximal LH response to LH-RH without DA infusion exceeded 153.5mIU/ml (mean + 2SD of young male subjects), and non-hyperresponders, in whom maximal LH responses to LH-RH without DA infusion were less than 153.5mIU/ml. In hyperresponders, serum LH response at 30 minutes after LH-RH administration was significantly (p less than 0.05) suppressed by DA infusion. In non-hyperresponders and young male subjects, however, serum LH response to LH-RH was not affected by DA infusion. Basal levels of serum LH and FSH in hyperresponders tended to be higher than that of non-hyperresponders. Total serum testosterone, free testosterone and estradiol levels of hyper and non-hyperresponders failed to reveal any significant differences. These observations suggest that 1) DA directly suppresses gonadotroph responsiveness to LH-RH, 2) in aging men, inhibitory tone imposed on gonadotrophs by DA is decreased, and 3) this decline of DA system can cause hypergonadotropism in aging men, independent of serum sex steroids levels.

Adult↗
PubMed1991

Lymphocytes cytotoxic to uveal and skin melanoma cells from peripheral blood of ocular melanoma patients.

To study antitumor immunity in patients with choroidal melanoma, T cells were generated from the peripheral blood of choroidal melanoma patients by mixed lymphocyte/tumor cell culture (MLTC). Because autologous tumors are generally unavailable, an allogeneic choroidal melanoma cell line, OCM-1, was used as the specific stimulus. Lymphocyte cultures from 27 patients were characterized by cell-surface phenotypes, patterns of reactivity towards cells of the melanocytic origin and T-cell-receptor gene usage. Antimelanoma reactivity was found in cell-sorter-purified CD4+ and CD8+ T cell subsets. To analyze this reactivity, sorter-purified CD4+ and CD8+ cells from a MLTC were cloned by limiting dilution in the presence of exogenous interleukin-2 and interleukin-4 as well as irradiated OCM-1. Under these conditions, CD4+ T cells did not proliferate, perhaps because of the absence of antigen-presenting cells. However, CD8+ grew vigorously and 29 cytolytic CD8+ T cell clones were isolated. On the basis of their pattern of lysis of OCM-1, a skin melanoma cell line M-7 and its autologous lymphoblastoid cell line LCL-7, the clones were categorized into three groups. Group 1, representing 52% of the clones, lysed all three target cells, and are alloreactive. However, since OCM-1 and M-7 did not share class I antigens, these clones recognized cross-reactive epitope(s) of the histocompatibility locus antigen (HLA) molecule. Group 2, constituting 28% of the clones, lysed both the ocular and skin melanoma cell lines but not LCL-7, and were apparently melanoma-specific. Unlike classical HLA-restricted cytolytic T lymphocytes, these T cells might mediate the lysis of melanoma cells via other ligands or a more degenerate type of HLA restriction. For the latter, the HLA-A2 and -A28 alleles would have to act interchangeably as the restriction element for shared melanoma-associated antigen(s). Group 3, representing only 10% of the T cell clones, was cytotoxic only to OCM-1, but not to M-7 or LCL-7. These clones may recognize antigens unique to ocular melanoma cells. Our data suggest that choroidal melanoma patients can recognize melanoma-associated antigens common to both ocular and cutaneous melanoma cells, and presumbly their autologous tumor. Thus, choroidal melanoma, like its skin counterpart, may be responsive to immunotherapeutic regimens such as active specific or adoptive cellular immunotherapy.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1991

Transforming growth factor (TGF)-beta like activity of intracranial meningioma and its effect on cell growth.

Polypeptides, characterized by their ability to confer a transformed phenotype on an untransformed indicator cell have been isolated directly from surgical specimens of intracranial meningioma by using an acid/ethanol extraction procedure. Transforming activity in meningeal cells was based on the ability to induce NRK 49F rat kidney fibroblasts to form colonies in soft agar. This polypeptide was separated by gel filtration into two fragments of 15 and 40 kilodalton (kDa) molecular weight. Among other cases of brain neoplasms, one case of glioblastoma multiforme had moderate TGF-beta activity, but medulloblastoma and neurinoma had no activity. Purified TGF-beta also stimulated DNA synthesis in primary cultured meningioma cells, but no effect was seen in U 251MG human glioma cells. While the physiological function of TGF-beta is still ill-defined and the molecular character of its receptor has not been analyzed, intracranial meningiomas are noted to have TGF-beta-like activity. TGF-beta also induces the DNA synthesis of cultured meningioma cells. From these results, TGF-beta would be considered one of the growth promoting factors in meningioma.

Animals↗
PubMed1991

Interleukin-2 activated T cells (T-LAK) express CD16 antigen and are triggered to target cell lysis by bispecific antibody.

Human PBMCs from healthy donors were cultured with 100 U/ml rIL-2 for up to 5 weeks and tested at short and long activation times for the ability to mediate CD3 and CD16 targeted cytotoxicity using chemically cross-linked bispecific antibodies. At each period, LAK activity was augmented with the use of bispecific antibodies (BA), whereas interestingly enough, at later periods (4-5 weeks) when CD16 positive lymphocytes are not present by flow cytometry, CD16 targeted cytotoxicity was induced. We suspected the possibility of CD16 expression on activated T cells and have purified the T cell subpopulations to see the targeted cytotoxicity. Populations enriched for T cells by Percoll density centrifugation, treatment with anti-CD16 plus complement or sorting for CD5+ cells, were all able to mediate CD16 targeted cytotoxicity following activation with rIL-2. These data suggest that IL-2 activated T cells express CD16 in addition to CD3.

Antibody Specificity↗
PubMed1991

Surrogate receptor-mediated cellular cytotoxicity against malignant human glioma cells.

A method for incorporating palmitate-derivatized antibody molecules into effector cells and the influence of these incorporated antibodies (surrogate receptors) on the lytic potential of peripheral blood lymphocytes is described. This surrogate receptor-mediated cellular cytotoxicity provides a means by which killer cells are directed specifically to the desired target glioma cells. The cytotoxic activity does not require the Fc region of the incorporated antibody molecules and shows more lytic potential than ordinary antibody-dependent cellular cytotoxicity. By complement-mediated cell depletion and Percoll gradient separation, the effector cell populations for surrogate receptor-mediated cellular cytotoxicity are found to be natural killer cells, as in the murine system. This strategy of surrogate receptor incorporation into effector cells may provide not only valuable insights into the mechanism of cell-mediated cytotoxicity, but also a means of generating target-specific effector cells for clinical applications in neurosurgery.

Animals↗
PubMed1991

Two distinct steps for spontaneous generation of subprotoplasts from a disintegrated bryopsis cell.

The unusual nature of protoplasm to generate subprotoplasts spontaneously from disintegrated Bryopsis cells was examined. Protoplasm extruded from algal cells aggregated rapidly in cell sap which was derived mainly from huge central vacuoles of the cells. Electron microscopic observations revealed extensive agglutination of algal cellular membranes in the protoplasmic masses, suggesting that this is of primary importance for the wound-healing ability of the alga. Seawater caused spheration of the resultant protoplasmic aggregates. Gelatinous sheaths were formed temporarily surrounding the spherical protoplasmic masses before reformation of cell membrane. Staining with phosphotungstic and chromic acids suggested that new cell membrane was formed by fusion of the disintegrated original cell membrane with cytoplasmic vesicles on the surfaces of the protoplasmic masses. Both pH and salts were found to be essentially important at the two steps of subprotoplast generation. The newly formed cell membranes were responsible for subsequent notable plasmolysis of the wounded cells in seawater. Thus, it is suggested that unicellular marine algae Bryopsis spp. naturally contain effective materials for agglutinating and fusing particular cellular membranes through the sequential aid of acidic cell sap and alkaline seawater after disintegration of the giant cells.

Journal Article↗
PubMed1991

Macrophage-dependent and B-cell-dependent proliferative T-cell populations in the peritoneal exudate cells of immunized mice.

The antigen-dependent proliferative response of the Ia- T lymphocyte population in peritoneal exudate cells (PEC) of C3H/HeN mice immunized with horse red blood cells (HRBC) was examined by determining the uptake of tritiated thymidine ([3H]TdR) into the cells in vitro. Both the antigen and accessory cell population, which was either macrophages or B lymphocytes that had been prepared from the PEC or spleen of unimmunized mice, were necessary for the proliferative response of the Ia- T cell population and also the production of IL-2 by the Ia- T cells, but the Ia- T cell population could proliferate in the absence of antigen and accessory cells, if IL-2 was present. The IL-2-dependent proliferation of the Ia- T cells was augmented in the presence of macrophages, but not B cells. The Ia- T cells that had been treated previously with anti-IL-2 receptor (IL-2R) antibody showed no response to IL-2 in the presence or absence of B cells, but responded to IL-2 in the presence of macrophages. Direct contact of the Ia- T cells with macrophages seemed to be necessary for augmentation of the proliferative response of the Ia- T cells to IL-2 because the separation of these cell populations by a membrane filter in a Marbrook type culture vessel resulted in poor augmentation of the response. Cell-associated IL-1 did not participate in the augmentation because paraformaldehyde-treated macrophages did not help the response. When the Ia- T cells had been previously treated with complement and anti-asialo GM1 antibody, the IL-2-dependent proliferative response was not affected, but the augmentation of the response by macrophages was blocked. Previous treatment of the cells with anti-L3T4 antibody diminished the response to IL-2, but did not affect the augmentation of the response by macrophages. Pretreatment of the cells with anti-Thy-1.2-antibody reduced the response to IL-2 and the augmentation by macrophages. Therefore, we concluded that there are at least two populations, capable of responding to IL-2 in the immune Ia- T cell population; one with L3T4 surface antigen and another with asialo GM1 antigen. The response of the latter cells, but not the former, to IL-2 is augmented in the presence of macrophages.

Animals↗
PubMed1991

[Expression of cytokine genes within astrocytoma cell lines and brain specimens].

Expression of the Cytokine genes in human astroglial cell lineage was studied. Primers for 5 different human cytokine, TNF-alpha, -beta, IFN-gamma, G-CSF and GM-CSF, were used to analyze messenger RNA transcripts in 5 cultured human astrocytoma, one neuroblastoma cell lines and fresh brain specimens by polymerase chain reaction (PCR). Three out of 5 unstimulated astrocytomas, U138, U251, U373 MG and IMR32 neuroblastoma cells expressed TNF-alpha genes. After stimulation with IL-1 beta (1000 U/ml) all these cell lines expressed TNF-alpha genes. TNF-beta genes could not be detected in these cell lines even in the presence of any cytokine stimuli. We were able to detect expression of IFN-gamma genes within 2 astrocytoma cell lines (U87MG and A172), which interestingly did not show TNF-alpha activity. Constitutive expression of mRNA transcripts of GM -CSF could be detected in all astrocytoma and two out of 5 unstimulated astrocytomas, U87MG and U138MG, expressed G-CSF genes. After stimulation with IL-1 beta, all cell lines expressed G-CSF. In addition, we also examined gene expression of these cytokines within 4 human malignant astrocytoma specimens, 2 peritumoral brain and 2 autopsied normal brains. The results show that tumor and surrounding lesions express TNF-alpha (4 of 6), TNF-beta (1/6), IFN-gamma (4/6), G-CSF (3/6) and GM-CSF (5/6) but not normal brains. One tumor specimen also expresses TNF-beta as well as TNF-alpha genes (case 2). From these results, it is suspected that astroglial cell-derived cytokines may participate in local immune reactions accompanying glioma in the brain.

Astrocytoma↗