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Biomedical subjects

K Isobe

Publications and source records attributed to K Isobe.

At least 217 records · Page 12Linked to original sources
PubMed1993

[Clinical problems in the management of aged patients with severe head injury: analysis of neurological findings and CT findings].

Aged patients were defined as those of 65 years or more of age. Among 457 patients with severe head injury [Glasgow Coma Scale score (GCS) of 8 or less], sixty-five aged patients (14%) were analyzed with special reference to their pretreatment neurological status, CT findings and outcome in comparison with 141 (31%) of those from 40 to 64 years of age. As a cause of injury, the incidence of traffic accidents and falls and tumbles did not differ statistically in both groups. Neither did the severity (GCS score) significantly differ in the two groups. Three important neurological findings [pupillary abnormality, impaired or absent oculocephalic reflex and poor motor response (GCS motor score < or = 3)], were analyzed as the prognostic factors. Poor motor response was the sole finding that was significantly more frequent in the aged. On CT in the aged, acute subdural hematoma was most common among the extraparenchymal hematoma. Hemorrhagic lesions were the more common parenchymal lesions. On the other hand, diffuse cerebral swelling was rare in the aged. The outcome was significantly poor in the aged; only 6% had good outcome (good recovery and moderate disability), and 80% died. In conclusion, these results suggested that the poor outcome was due to severe primary brain damage added to poor brain plasticity in the aged.

Adult↗
PubMed1993

Transforming growth factor-beta 1 enhances the generation of allospecific cytotoxic T lymphocytes.

We investigated the effects of transforming growth factor-beta 1 (TGF-beta 1) on the proliferation and generation of murine T lymphocytes in vitro. TGF-beta 1 suppressed T- and B-lymphocyte proliferation, mixed lymphocyte reaction (MLR), and the generation of natural killer (NK) cells and lymphokine-activated killer (LAK) cells. On the other hand, TGF-beta 1 significantly enhanced the generation of allospecific cytotoxic T lymphocytes (CTL) at low concentrations (0.01-1 ng/ml) in a dose-dependent manner and restored it to the control level at higher concentrations (10-40 ng/ml). Allospecific CTL generation by TGF-beta 1 was maximally enhanced when added at the beginning of culture. Less enhancement occurred when the addition was delayed. Anti-TGF-beta 1 antibody completely abolished the enhancing effects of TGF-beta 1. Furthermore, platelet-derived TGF-beta (pTGF-beta) as well as recombinant TGF-beta 1 similarly enhanced the generation of allospecific CTL. These data demonstrate that TGF-beta has not only immunosuppressive effects but also immuno-enhancing effects in vitro.

Animals↗
PubMed1993

Glycyrrhizin as a promoter of the late signal transduction for interleukin-2 production by splenic lymphocytes.

Cellular and molecular mechanisms of the immunomodulatory action of glycyrrhizin (GL) were studied. We demonstrated that GL displays a unique action to prolong the duration of the T-cell receptor-mediated in vitro splenic T-lymphocyte growth response to anti-CD3 monoclonal antibody (mAb) or concanavalin A (Con A) through enhancement of interleukin-2 (IL-2) secretion and IL-2 receptor (IL-2R) expression. The augmentation by GL of IL-2 production was also found in spleen cells stimulated with A23187 plus phorbol 12-myristate 13-acetate (PMA), suggesting that GL primarily affects some post-receptor stage of the signal transduction. We also found that the time of GL action for promoting IL-2 production and growth response was 2 hr or more after receptor activation. Correspondingly, GL did not augment the anti-CD3 mAb or Con A-mediated protein tyrosine phosphorylation and c-fos transcription. We concluded from these results that GL acts as a promoter of the late signal transduction of T lymphocytes for IL-2 production.

Animals↗
PubMed1993

[Pathogenesis and management of secondary neural damage in head trauma patients: analysis of patients who talk and deteriorate "fulminantly"].

To clarify the pathogenesis and management of secondary neural damage after head trauma, we characterized the clinical features and CT findings in nine patients who talked and deteriorated "fulminantly". The patient who talks and deteriorates "fulminantly" is defined as a patient who talks (verbal score of Glasgow Coma Scale > or = 4) on admission, and subsequently shows a rapid neurological deterioration to develop an anisocoria and/or a decerebrated posture within 24 hours after trauma. Nine (8%) out of 118 patients with severe head trauma satisfied the definition mentioned above. The mechanism of injury was a fall in 5 patients and a road traffic accident in 4. Plain skull X-ray manifested a linear skull fracture in 8 out of 9 (89%). Although they were almost alert and talked on admission, all of these 9 patients developed an anisocoria within 6 hours after trauma. Prior to the rapid neurological deterioration, in spite of their good consciousness, they characteristically showed a variety of CT abnormalities including subdural hematoma (SDH), intracerebral hematoma (ICH) and subarachnoid hemorrhage. Following the rapid neurological deterioration, 7 out of 9 patients underwent surgical treatment for hematoma evacuation using a large decompressive craniectomy. Clinical outcomes were 2 good recoveries, 1 moderate disability, and 6 deaths. Causes of the rapid neurological deterioration determined by CT and surgery were: 1) an enlarged SDH in 6 patients, 2) an enlarged ICH in 4 patients, and 3) a worsened brain swelling associated with SDH in 3 cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Delivery of an accessory signal for cell activation by exogenous phosphatidylinositol-specific phospholipase C.

Digestion of phosphatidylinositol (PI) or glycosylphosphatidylinositol (GPI) anchors of membrane proteins on the external cell surface with exogenous PI-specific phospholipase C (PIPLC) from Bacillus thuringiensis was shown to transmit a signal into the thymocyte to modulate the TCR/CD3 complex-induced signal delivery for cell activation. This was demonstrated for very early protein tyrosine phosphorylation, early c-fos transcription and late DNA synthesis. For this effect preincubation of the cells with PIPLC was required, but there was no evidence of involvement of any soluble products released from the cell surface by PIPLC in the signaling, suggesting a crucial role of the membrane-bound counterpart (diacylglycerol or diradylglycerol) of the PI/GPI hydrolysate. A possible role for this accessory signal in the microorganism-linked control of the (diacylglycerol or diradylglycerol) of the PI/GPI hydrolysate. A possible role for this accessory signal in the microorganism-linked control of the T cell receptor function is discussed.

Animals↗
PubMed1992

Expression of MDR1 and glutathione S transferase-pi genes and chemosensitivities in human gastrointestinal cancer.

The relationship was analyzed between drug resistance and MDR1 (with MDR signifying multiple drug resistance) and glutathione S transferase-pi (GST-pi) gene expression in four stomach and four colon cancer cell lines. Northern blot analysis by pmdr1 probe showed that stomach cancer cell lines had no detectable level of MDR1 mRNA expression. By contrast, some levels of MDR1 mRNA expression were found in two colon cancer cell lines, indicating doxorubicin resistance. To examine the MDR1 mRNA in each cell level, in situ hybridization was used. It was found that all colon cell lines and two stomach cell lines had more silver grains per cell than KB cells (a human KB kidney epidermoid carcinoma cell line). However, the number of silver grains in each cell was heterogeneous in the colon and stomach cell lines. Low-level MDR1 mRNA expression could be detected even in cell lines without MDR1 mRNA expression by northern blot hybridization. These results suggest the possibility that all gastrointestinal cell lines can acquire multiple drug resistance. In addition, all examined gastrointestinal cell lines had high GST-pi mRNA expression. This GST-pi gene expression shows cisplatin resistance in the examined cell lines. Heterogeneity of GST-pi mRNA expression also was shown at the cellular level.

Adenocarcinoma↗
PubMed1992

Crystallization and characterization of monoacylglycerol and diacylglycerol lipase from Penicillium camembertii.

A new lipase from Penicillium camembertii U-150, which is specific for monoacylglycerols and diacylglycerols, but not triacylglycerols, was purified as four active components using concanavalin-A-Sepharose column chromatography, crystallized in the form of needles, and its properties investigated. No significant difference was observed in substrate specificity, but molecular mass and other enzymatic properties, such as pH, heat stability and optimum pH and temperature, were clearly different between the unadsorbed and the three adsorbed components on concanavalin-A-Sepharose; the three adsorbed components were similar to each other and more stable than the unadsorbed component. On the other hand, after enzymatic removal of carbohydrates from the three adsorbed components, their enzymatic properties became similar to those of the unadsorbed component. The carbohydrates of this lipase contribute to the stability of the enzyme, but not to its enzyme activity. The amino acid compositions of the four components did not differ from each other, and tryptic mapping of the deglycosylated components and amino acid composition of the tryptic fragments were identical. The carbohydrate compositions of four intact components were, however, different from each other. All four components have the same polypeptide backbone and multiple forms of this lipase are due to the differences in composition of the carbohydrates bound in this lipase.

Amino Acids↗
PubMed1992

Bidirectional control by glycyrrhizin of the growth response of lymphocytes stimulated through a receptor-bypassed pathway.

This study demonstrates a unique action of glycyrrhizin (GL) in bidirectionally controlling the growth response of lymphocytes stimulated through a receptor-bypassed pathway by calcium ionophore A23187 and phorbol 12-myristate 13-acetate (PMA). GL up-regulated the response of lymphocytes in vitro to lower concentrations of A23187 and PMA, and down-regulated the response to higher concentrations. We also provide evidence that GL controls the response of lymphocytes of different cell types or maturation stages in different ways, probably because these lymphocytes require different levels of signals as optimum. Finally, the GL-mediated bidirectional controls of the lymphocyte growth response were shown to be adherent cell-independent. The bidirectional controls demonstrated may be significant in normalizing the lymphocyte responses to very weak or very high stimuli.

Animals↗
PubMed1992

Determination of the molecular weights of ribonuclease isozymes in a cell-free crude extract of Dictyostelium discoideum, by activity-staining of gels after SDS-PAGE.

1. In a previous report we described three isozymes of intracellular ribonuclease in Dictyostelium discoideum, which were found in vegetative cells. Here we report that the molecular weights of the three isozymes from vegetative cells. 2. They are 14.3 kDa, 60 kDa and 80 kDa, as determined by activity-staining of gels after SDS-PAGE. 3. For renaturation of ribonucleolytic activity from D. discoideum cells after SDS-PAGE, fibrinogen-containing gels were used and gels were washed in aqueous isopropanol to remove detergent. Results of studies by this method suggest that each of these isozymes is composed of only a single polypeptide. 4. The effect of the buffer system on this technique is discussed.

Animals↗
PubMed1992

Prediction of doxorubicin resistance in gastrointestinal cancer by P-glycoprotein staining.

Feasibility of immunohistochemical staining of P-glycoprotein for the prediction of doxorubicin resistance in gastrointestinal cancers was examined. Among 10 cancer cell lines which consist of two gastric cancer cell lines and eight colon cancer cell lines, seven cell lines were stained positively by the monoclonal antibody to P-glycoprotein, C219. In consequence of the evaluation on the effect of doxorubicin on these tumour cells by means of succinic dehydrogenase inhibition test (SDI test), zero out of seven cell lines stained positively by C219 was sensitive to doxorubicin, but two out of three cell lines stained negatively were sensitive. Among 23 fresh surgical specimens of gastrointestinal cancers which consisted of 15 gastric cancers and eight colon cancers, seven tumour tissues were stained positively by C219. All P-glycoprotein positive tumours were resistant to doxorubicin. On the other hand, four of 16 P-glycoprotein tumours were sensitive to doxorubicin. These data indicate that positively stained cancer cells by C219 are resistant to doxorubicin.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1992

T cell maturation stage-linked heterogeneity of the glycosylphosphatidylinositol membrane anchor of Thy-1.

We showed that some of Thy-1 molecules on murine thymocytes are resistant to phosphatidylinositol-specific phospholipase C (PI-PLC) derived from Bacillus thuringiensis. Both immature thymocytes with low CD3 expression and mature thymic T lymphocytes with high CD3 expression carried the PI-PLC-resistant Thy-1, and the PI-PLC-sensitivity of Thy-1 extensively varied among thymocyte subpopulations. In contrast, the same PI-PLC fully hydrolysed the anchor of Thy-1 on peripheral T lymphocytes. When the latter cells were activated with mitogen in vitro, however, some Thy-1 on them became resistant to PI-PLC. We then found that virtually all Thy-1 molecules on thymocytes became sensitive to PI-PLC when they were treated with hydroxylamine that should cleave ester-linked lipids. The result ruled out the possibility that the PI-PLC-resistant Thy-1 had a transmembranous peptide sequence, and suggested the presence of an additional fatty acyl group on the inositol ring of the Thy-1 anchor. In addition, the molecular size of the PI-PLC-resistant membrane-bound Thy-1 was only marginally larger than that of the PI-PLC-sensitive solubilized Thy-1 in detergent-partitioning SDS-PAGE analysis.

Animals↗
PubMed1992

Mechanical stability of the pedicle screw fixation systems for the lumbar spine.

Five different pedicle screw systems: AO Fixator Interne, VSP Steffee plate, Luque ISF, modified Zielke, and Chiba-type plate screw system (experimental device), were evaluated for biomechanical strength. A fatigue test for the screw, compressive, and torsional tests for the pedicle screw systems and a pull-out test of the pedicle screw were done. Even the Schanz screw, which showed the highest endurance limit, may be broken under the continuous loading condition in the body. The AO Fixator Interne and Steffee plate system themselves are rigid and are indicated for injuries that need reduction. The Luque ISF, modified Zielke, and Chiba-type plate screw systems, however, are indicated for degenerative lumbar disease requiring in situ fusion. There was a linear positive correlation between the bone mineral density of the vertebral body and the pull-out strength of the pedicle screw (correlation coefficient, 0.68). The fixation strength of the pedicle screw to the bone decreased remarkably in osteoporosis.

Biomechanical Phenomena↗
PubMed1992

Further evaluation of the pregnancy-linked down-regulation of the paternal antigen-specific splenic cytotoxic T lymphocyte activity in allogeneically pregnant mice.

Cytotoxic T lymphocyte (CTL) activity directed against paternal alloantigen was examined in allogeneically pregnant mice using various allogeneic combinations. The spleen cells from pregnant C57BL/6 (H-2b) mice mated with BALB/c (H-2d) male mice generated less anti-H-2d CTL after in vitro sensitization than those from unpregnant or syngeneically mated C57BL/6 mice. Different allogeneic combinations including the incompatibility at only D region of H-2 or minor histocompatibility loci were effective for downregulating the anti-paternal CTL activity in pregnancy. The downregulation of anti-paternal CTL activity induced by allogeneic pregnancy occurred at day 10 to day 18 of pregnancy, most extensively at day 14. The allogeneic pregnancy also downregulated the allogeneic CTL activities that had been amplified by injecting alloantigens before mating.

Animals↗
PubMed1992

Establishment of transplantable tumor lines and in vitro cell lines of malignant thymoma developed in a BUF/Mna rat.

A spontaneous malignant thymoma was found in an 18-month-old female BUF/Mna rat and serially transplanted subcutaneously in both syngeneic BUF/Mna rats (designated as MTH-R) and KSN nude mice (MTH-NM) for more than 5 years. Both tumors shared the histological appearance of sarcomatoid carcinoma as seen in the original tumor. However, MTH-NM grew faster than MTH-R in the respective hosts. The MTH-NM grew in both KSN-nude mice and BUF/Mna-rnu/rnu rats but not in BUF/Mna rats, the host of the original tumor. Three continuous tissue culture cell lines (MTHC-1, MTHC-2 and MTHC-3) were established from the MTH-NM tumors at the 2nd, 15th and 17th transplantation generations, respectively. The MTH-NM tumors and latter two tissue culture cell lines carried one or more mouse chromosomes, probably acquired by cell fusion with mouse cells during passages in vivo. The presence of the mouse chromosomes was confirmed by the presence of mouse DNA and of antibodies to the MTHC-2 and MTHC-3 cells in the sera of BUF/Mna rats transplanted with MTH-NM.

Animals↗
PubMed1992

Transfer of specific IgG and IgG subclasses to herpes simplex virus across the blood-brain barrier and placenta in preterm and term newborns.

The kinetics of virus-specific IgG subclasses (IgG 1-4) among newborns and their mothers has not yet been determined. In this report, we examined anti-herpes simplex virus IgG activities (HSV-IgG) and its subclasses in CSF and serum of premature or term newborns without HSV infection and in the serum of their mothers using ELISA. We found that CSF/serum ratios of HSV-IgG and IgG subclasses (IgG 1-4) in newborns with a gestational age less than 38 weeks were higher than those of term newborns. These findings indicate that the blood-brain barrier against HSV-IgG and IgG subclasses is insufficient in newborns. Furthermore, we found that HSV-IgG subclasses, which were transferred across the placenta and later transferred across the blood-brain barrier had a tendency to be proportional to each of the maternal HSV-IgG subclasses.

Antibodies, Viral↗
PubMed1992

Feedback suppression of staphylococcal enterotoxin-stimulated T-lymphocyte proliferation by macrophages through inductive nitric oxide synthesis.

Staphylococcal enterotoxin A (SEA)- or SEB-stimulated T-lymphocyte proliferation was suppressed by the addition of high numbers of murine peritoneal macrophages or rat peritoneal or alveolar macrophages, whereas lower numbers of murine peritoneal macrophages enhanced the T-lymphocyte response. Suppression was associated with the increase of accumulation of nitrite, a product of nitric oxide, in the culture supernatants. This macrophage-mediated suppression was totally reversed by the addition of NG-monomethyl-L-arginine, a homolog of L-arginine, indicating that macrophage-mediated suppression of T-lymphocyte proliferation was mediated through the nitric oxide-synthesizing pathway activity. Macrophages in large numbers spontaneously produced nitric oxide in culture supernatant fluids. By the addition of autologous or allogeneic spleen cells but not thymocytes to SEA- or SEB-stimulated macrophage culture, nitric oxide production was greatly increased. When T lymphocytes in spleen cells were killed by antibody before addition to macrophage culture, nitric oxide production was diminished to the basal level. These results suggest that in addition to the action to support the process of T-lymphocyte activation by SEA or SEB, macrophages display a feedback regulatory action on the SEA- or SEB-stimulated T-cell proliferative response by releasing nitric oxide through interaction between macrophages and activated T lymphocytes.

Animals↗
PubMed1992

Klinefelter's syndrome accompanied by diabetes mellitus and diabetes insipidus.

The first case of Klinefelter's syndrome accompanied by diabetes insipidus and diabetes mellitus is reported. A 41-year-old man admitted for hyperosmolar diabetic coma with a past history of diabetes insipidus was diagnosed as having Klinefelter's syndrome by endocrinological examination and sex chromosome analysis. In this case, glucose tolerance test was normalized half a year later and blood glucose was well controlled with diet therapy alone.

Adult↗