Biomedical subjects

K Ohsawa

Publications and source records attributed to K Ohsawa.

At least 55 records · Page 3Linked to original sources

PubMed1997

Two cases of transiently TSBAb-positive hypothyroidism induced by interferon-alpha therapy for chronic hepatitis C.

A 34-year-old woman and a 54-year-old woman were treated with interferon-alpha (IFN-alpha) for chronic hepatitis C. Three months after the cessation of the IFN-alpha therapy, each patient developed hypothyroidism with the presence of thyroid-stimulation-blocking antibody (TSBAb) and TSH-binding inhibitor immunoglobulin (TBII). These two patients were treated with thyroxine, and both TSBAb and TBII activities gradually decreased. Although both TSBAb and TBII became negative several months after the start of the replacement therapy, the replacement dosage of L-thyroxine could not be reduced. Thyroid biopsies showed that the follicular epitheliums were flattened in both cases with lymphocytic infiltration. These findings suggest that IFN-alpha may induce hypothyroidism and the transient emergence of TSBAb and TBII.

Adult↗

PubMed1997

Generation and characterization of a microglial cell line, MG5, derived from a p53-deficient mouse.

We have established a cell line cloned from primary-cultured microglia obtained from p53-deficient mice. The cell line, MG5, could be grown in astrocyte-conditioned medium and has been maintained for more than a year. MG5 cells are immunocytochemically positive for Mac-1 and F4/80 antibody and express the major histocompatibility complex (MHC) class I antigen, leukocyte function-associated antigen-1, leukocyte common antigen, and intercellular adhesion molecular-1 mRNA. Interferon-gamma enhanced the expression of MHC class II antigen mRNA in MG5 cells. We previously identified a novel calcium-binding protein, Iba1 (ionized calcium-binding adapter molecule 1), which is highly and specifically expressed in cultured microglia. Iba1 protein was also immunocytochemically demonstrated in MG5 cells. The cells retained non-specific esterase activity, 5'-nucleotidase activity, acid phosphatase activity, and phagocytic ability. Like primary cultured microglia from wild-type mice, MG5 cells released nitric oxide in response to lipopolysaccharide, and actively proliferated in the presence of mitogenic factors such as macrophage-colony stimulating factor (M-CSF), granulocyte/macrophage-CSF (GM-CSF), and interleukin-3 (IL-3). Tyrosine-phosphorylation of M-CSF receptor in MG5 cells was induced by the addition of M-CSF or astrocyte-conditioned medium. These findings indicate that MG5 cells preserve the morphological, biochemical, and physiological properties of primary-cultured microglia well. The MG5 cell line will be a useful tool for studying microglial function.

5'-Nucleotidase↗

PubMed1996

A novel gene iba1 in the major histocompatibility complex class III region encoding an EF hand protein expressed in a monocytic lineage.

We successfully isolated a rat cDNA clone encoding a novel EF hand protein with a molecular weight of about 17 kDa and designated this gene iba1 (ionized calcium binding adapter molecule 1). The genomic copy of the iba1 gene was located within a segment of the major histocompatibility complex class III region between the Bat2 and TNF alpha genes. The iba1 gene was shown to be highly expressed in testis and spleen, but weakly expressed in brain, lung, and kidney. Among brain cells, the iba1 gene was specifically expressed in microglia. A screening of hemopoietic cell lines showed that the Iba1 protein was clearly expressed in monoblastic cell lines but only very weakly expressed in myeloid cell lines. Iba1 protein is therefore suggested to act as an adapter molecule, mediating calcium signals that may function in a monocytic lineage including microglia.

Amino Acid Sequence↗

PubMed1996

Molecular cloning and characterization of annexin V-binding proteins with highly hydrophilic peptide structure.

We previously reported that annexin V promoted the survival of cultured rat neocortical neurons. In an effort to elucidate the mechanism underlying this neurotrophic activity of annexin V, we have attempted to identify the target or binding proteins of annexin V in neuronal cells. Herein, we screened an embryonic day 17 rat brain cDNA library by western blot using glutathione S-transferase-annexin V fusion protein as a probe and then isolated four clones showing binding to annexin V in a Ca2+ - and phospholipid-dependent manner. Although these cDNAs encoded different polypeptides, all four polypeptides shared the unique feature of containing highly hydrophilic stretches with high Lys, Glu, and Ser contents. Deduced amino acid sequences of two clones showed high homology with human X-linked Helicase2 (XH2) and DNA (cytosine-5) methyltransferase (DMTase) sequences, whereas the other two were not related to any known peptide sequence. These results suggest that XH2 and DMTase are candidates for annexin V-binding proteins and thus may mediate the biological activity of annexin V.

Animals↗

PubMed1996

The first case of insulin-dependent diabetes mellitus with prominent spurious hyperglucagonemia due to interference of immunoglobulin G in glucagon radioimmunoassay (OAL-123) system.

A 51-year-old male was admitted to our hospital because of diabetic ketoacidosis. His symptoms were promptly improved with intensive insulin therapy, but his plasma glucagon immunoreactivity measured by the OAL-123 radioimmunoassay (RIA) system showed persistently high values (3,090-3,210 pg/ml). A computed tomographic scan, abdominal angiography and endoscopic examination of his gastrointestinal tract showed no evidence of glucagonoma. After removing the immunoglobulin fraction from the plasma, his immunoreactive plasma glucagon level returned to normal. Moreover, the immunoglobulin G fraction purified from the patient's plasma inhibited the binding of [125I]glucagon to rabbit antiglucagon antiserum, OAL-123. Dot-blot analysis demonstrated that the immunoglobulin G of this patient cross-reacted against OAL-123. Therefore, it was considered that the prominent hyperglucagonemia in this patient was due to the presence of IgG, which interfered with the measurement of plasma-immunoreactive glucagon.

Diabetes Mellitus, Type 1↗

PubMed1996

[A simultaneous determination of various main components in oriental pharmaceutical decoction "heii-san" by ion-pair high-performance liquid chromatography].

A simple and precise method was established for the simultaneous determination of five selected marker components in oriental pharmaceutical decoction "Heii-San" by means of high-performance liquid chromatography using tetra-n-amylammonium bromide (TAA) as an ion-pair reagent. For the separation of these five components, such as hesperidin (1), 6-gingerol (2), honokiol (3), glycyrrhizin (4) and magnolol (5), an ODS column was used with multi-step gradient elution with 10 mM TAA (H3PO4, pH 4.0)-acetonitrile. The acetonitrile content linearly increased from 25 to 90%. This method was compared with other three methods, i.e. a water-acetonitrile method, a phosphate buffer method and an ion-suppression method. Five main components were eluted within 50 min without interference from co-existing components.

Chromatography, High Pressure Liquid↗

PubMed1996

[A simultaneous determination of evodiamine and rutaecarpine in oriental pharmaceutical decoctions containing Evodia fruit by ion-pair high-performance liquid chromatography].

A simple and precise method was established for the simultaneous determination of evodiamine and rutaecarpine in oriental pharmaceutical decoctions containing Evodia Fruit using high-performance liquid chromatography with sodium dodecyl sulfate (SDS) as an ion-pair reagent. Evodiamine and rutaecarpine were eluted within 60 min without interference from co-existing components using an ODS column and a mixture of water-methanol-acetonitrile-SDS-phosphoric acid (600:330:70:5:0.01, v/v/v/w/v, pH 5.0) as a mobile phase.

Alkaloids↗

PubMed1996

Effect of interferon-beta on thyroid function in patients of chronic hepatitis C without preexisting autoimmune thyroid disease.

The effect of interferon-beta (IFN-beta) on thyroid function was studied in patients with chronic hepatitis who had no preexisting thyroid disease. Eleven patients (9 males and 2 females) aged 20 to 65 years, with a mean age of 47.7 +/- 13.5 years, were treated with 6 million units of IFN-beta intravenously every day for 8 weeks. During IFN-beta administration (4th to 8th week of treatment), both serum free thyroxine (FT4) and free triiodothyronine (FT3) concentrations decreased significantly (P < 0.0005 and P < 0.05, respectively): FT4, 1.37 +/- 0.17 to 1.09 +/- 0.12 ng/dl, and FT3, 3.71 +/- 0.45 to 3.28 +/- 0.34 pg/ml. On the other hand, serum TSH increased significantly from a baseline of 1.70 +/- 0.82 to 3.34 +/- 1.98 microU/ml during IFN-beta administration (P < 0.005). Four to eight weeks after cessation of treatment, the mean serum FT4 concentration was similar to that during IFN-beta administration (1.04 +/- 0.14 ng/dl), but mean serum FT3 and TSH concentrations returned to pre-treatment levels (FT3, 3.57 +/- 0.42 pg/ml and TSH, 1.60 +/- 0.84 microU/ml). Both reverse T3 and thyroglobulin were essentially unchanged. Tests for anti-thyroglobulin and anti-microsomal antibodies were negative in all the patients. These results indicate that IFN-beta may inhibit thyroid function in patients without preexisting thyroid disease irrespective of humoral immune responses.

Adult↗

PubMed1996

Replication of rat coronaviruses in intestinal cell line, RCN-9, derived from F344 rats.

To examine the susceptibility of the epithelial cell line to rat coronavirus (RCV), we inoculated sialodacryoadenitis virus and Parker's RCV into five cell lines; JTC-19, rat L2, LLC, RCN-9 and LBC cells originating in the lungs, intestines and mammary tumors of rodents. Both RCVs were replicated in LBC and RCN-9 cells, but not in the others. The infectivity titers of both RCVs grown in RCN-9 cells were significantly higher than those in LBC cells in every passage (2.5-3.9 log rate). Both RCVs replicated in LBC cells showed higher tropism to RCN-9 cells than to LBC cells, suggesting that RCN-9 cells are more suitable for the replication of RCVs than LBC cells. The RCN-9 cell line would be useful for the investigation of RCV infection in rodents.

Animals↗

PubMed1996

Inhibitory effect of cyclosporin A on prolactin synthesis in GH3 cells.

Cyclosporin A (CsA), a potent immunosuppressant, is known to have various effects on the endocrine system, including the pituitary gland, the adrenal cortex, the testes, and the pancreatic islets. In this study, the effects of CsA on prolactin (PRL) synthesis and release were investigated in GH3 cells, a clonal strain of rat pituitary tumor. After incubation of confluent GH3 cells with various concentrations of CsA for 24 hr, the PRL content of the media decreased in a dose-dependent manner: by 28.5% with 100 ng/ml CsA (p < 0.01); and 45.8% with 2,000 ng/ml CsA (p < 0.001), compared with control. However, no significant change was observed in the intracellular PRL content. After removal of CsA from the medium, GH3 cells fully recovered normal secretory activity within 24-48 hr, thus indicating that the inhibitory effect of CsA on PRL secretion was reversible. Northern blot analysis revealed a decrease in the PRL mRNA level in cells treated with CsA. In conclusion, these data suggest that CsA inhibits PRL secretion by reducing the rate of biosynthesis. A possible site of action is on PRL gene expression at the level of mRNA transcription.

Animals↗

PubMed1996

[Contingent negative variations associated with vocalization in humans].

We investigated the late negative components of the contingent negative variations (CNVs) in the verbalization task. Six subjects were instructed to perform three different motor tasks, jaw opening, vocalization of a meaningless sound and that of a word, in response to a sound stimulus following a visual warning stimulus with interstimulus interval of 4.0 sec. The electroencephalograms (EEGs) were recorded from the midline-central (Cz), left and right temporal areas (T3 and T4) and frontal areas (F7 and F8). EEGs were averaged 16 times using the visual stimulus pulse as a trigger to obtain the CNVs in each motor task. There was no significant difference between the tasks of the jaw opening and vocalization of the sound in the CNV amplitudes at bilateral electrodes. However, the amplitudes of the CNVs at the left frontal and temporal areas were significantly larger in the case of vocalization of the word than in that of jaw opening (p < 0.05). On the other hand, there was no significant difference between these two tasks in the CNV amplitudes at the right frontal and temporal areas. Our results suggested that the CNVs generated over the left hemisphere might reflect the brain activities involved in language production.

Adult↗

PubMed1995

Receptor-mediated toxicity to pericytes of advanced glycosylation end products: a possible mechanism of pericyte loss in diabetic microangiopathy.

The influence of advanced glycosylation end products (AGE) on bovine retinal pericytes was investigated. When pericytes were cultured with AGE-bovine serum albumin (BSA), pericyte growth was significantly retarded in a dose-dependent manner. They also exhibited an immediate toxicity to pericytes. However, MRC-5 human fibroblasts were totally resistant to AGE-BSA. Moreover, antisense oligonucleotides complementary to mRNA coding for AGE receptor were found to reverse the AGE-induced decrease in viable pericyte number, although the mRNA level was about one order of magnitude lower in pericytes than in the fibroblasts. These results indicate that pericytes may possess a peculiar sensitivity to AGE, and that AGE ligand-receptor interactions may play an important role in the pathogenesis of pericyte loss, the principal change in diabetic microangiopathies.

Animals↗

PubMed1995

Urinary and biliary metabolites of puerarin in rats.

Examination was made of the urinary and biliary excretion of the metabolites of puerarin, the major component of the roots of Pueraria lobata OHWI (Leguminosae) in rats. The urine of rats administered puerarin orally contained puerarin and four major metabolites, daidzein 4',7-di-O-sulfate (M-I), daidzein 7-O-beta-D-glucuronide (M-II), daidzein 4'-O-sulfate (M-III), daidzein (M-IV), as determined from spectroscopic and chemical data. Total cumulative amounts of the puerarin and four metabolites excreted in the urine at 48 h following the oral administration of puerarin were approximately 3.6% the doses administered. The bile of rats administered puerarin orally contained puerarin and two major metabolites, which were identified as puerarin 4'-O-sulfate (PB1) and puerarin 7-O-beta-D-glucuronide (PB2) on the basis of chemical and spectroscopic data. These experimental data suggest that C-glycoside puerarin is partially hydrolyzed to aglycone in the body, but mainly excreted in the urine as unchanged puerarin.

Animals↗

PubMed1995

Hantaan virus persistently infects marmoset B-lymphoblastoid cell line.

To investigate lymphoid cell Hantavirus (HV) interaction, we examined the replication of the HV strains, Hantaan 76-118 (HTN), SR-11, and B-1 with the B95a, LYM-1, CGM1, JM, Jurkat, MOLT-4, AT(L)5KY, BW5147, L1210, and Vero/E6 cells. HV-growth was determined by immunofluorescence and focus-forming assays. LYM-1 and Vero/E6 supported the growth of all HV strains, and B95a only HTN, while remaining cells did not sustain these strains. This is the first report to indicate the HV-replication in lymphoid cell lines. B95a and LYM-1 cells may be useful for revealing the mechanism of HV-infection in animals.

Animals↗

PubMed1995

An adult case of neurohypophyseal ectopy presenting ACTH deficiency and partial GH deficiency.

A case of ACTH deficiency and partial GH deficiency associated with neurohypophyseal ectopy is described. A 42-year-old woman of short stature was admitted for hypoglycemic coma. The patient had hypocortisolemia, an increase in urinary 17-OHCS after consecutive injections of ACTH-Z, and a low plasma ACTH level which showed no response to corticotropin-releasing factor. This indicated the presence of ACTH deficiency. The plasma GH level showed a blunted response to insulin-induced hypoglycemia, but its response to GRF was preserved. Other hypothalamo-pituitary axes were intact. T1-weighted magnetic resonance imaging demonstrated ectopic neurohypophyseal tissue and a tiny anterior pituitary remnant. ACTH deficiency and partial GH deficiency might have developed as a consequence of pituitary stalk injury and inadequate regeneration of the anterior lobe.

Adrenocorticotropic Hormone↗

PubMed1995

New isolates of pneumonia virus of mice (PVM) from Japanese rat colonies and their characterization.

Two virus strains were isolated from the lungs of athymic rats and mice used as sentinel animals in 2 colonies of laboratory rats in Japan in which antibodies to the pneumonia virus of mice (PVM) had been detected. The new isolates were identified as PVM by the following characteristics: RNA virus, susceptibility to ether treatment, long filamentous viral structure in the cytoplasm of infected cells, and hemagglutinating activity in various erythrocytes, including those of mice and rats. In addition, cross neutralization with the prototype of PVM (No. 15 strain) was observed. This is the first report of the isolation of PVM from laboratory animals in Japan.

Animals↗

PubMed1994

Synthetic peptide corresponding to 30 amino acids of the C-terminal of neuron-specific enolase promotes survival of neocortical neurons in culture.

Neuron-specific enolase (NSE), one of the glycolytic enzymes, is a gamma gamma-isozyme of enolase that is specifically expressed in neurons. Our previous studies demonstrated that NSE promotes survival of rat embryonic neocortical neurons in culture but that the alpha alpha-isozyme (non-neuronal enolase; NNE) has no effect. In this study, we found that a synthetic peptide corresponding to the C-terminal portion of NSE (404-433) also promotes the survival of neocortical neurons. By contrast, a synthetic peptide of the C-terminal portion of NNE (404-433) has no effect on neuronal survival. These findings would be important for further analysis of the neurotrophic mechanism of NSE.

Amino Acid Sequence↗

PubMed1994

Neurotrophic effects of annexin V on cultured neurons from embryonic rat brain.

Recombinant human annexin V showed survival promoting activity in embryonic rat neocortical and mesencephalic neurons in vitro. The neurotrophic effect was observed from a relatively low dose and in a dose-dependent manner. The neurotrophic activity of annexin V was completely blocked by anti-annexin V antibody. Northern blot analysis demonstrated that annexin V mRNA is expressed in non-neuronal cells in the CNS. These results suggest that annexin V plays certain roles in the CNS as a paracrine-type neurotrophic factor.

Amino Acid Sequence↗