Biomedical subjects

T Okado

Publications and source records attributed to T Okado.

At least 19 recordsLinked to original sources

PubMed2001

Glucocorticoids stimulate p21(CIP1) in mesangial cells and in anti-GBM glomerulonephritis.

BACKGROUND: Glucocorticoids are widely used for the treatment of glomerulonephritis, but the mechanism of cell cycle inhibition by glucocorticoids is poorly understood at a molecular level. METHODS: The effects of dexamethasone on cell cycle progression were examined in rat mesangial cells. To investigate the mechanisms of cell cycle inhibition by dexamethasone, we transfected the -2.3 kb p21(CIP1) promoter-CAT construct to mesangial cells using an electroporation METHOD: We also examined whether glucocorticoids stimulate the expression of p21(CIP1) and inhibit cell proliferation in glomeruli of anti-glomerular basement membrane (GBM) glomerulonephritis in rats. RESULTS: Dexamethasone inhibited 3H-thymidine uptake and the percentages of S and G2/M phases in rat mesangial cells. Dexamethasone stimulated CAT activity of the p21(CIP1) promoter 4.5-fold. Deletion analysis of the p21(CIP1) promoter revealed that the glucocorticoid-responsive region (GRE) is present between -1.4 and -1.1 kb upstream of the transcription initiation site. Dexamethasone inducibility of p21(CIP1) promoter activity requires the presence of the C/EBP alpha DNA binding site in the GRE of the p21(CIP1) promoter and C/EBP alpha protein. Intravenous injection of anti-GBM antibody caused mesangial proliferation, crescent formation, and proteinuria in rats. Ten days of administration of prednisolone (1 mg/kg/day) reduced proteinuria and inhibited mesangial cell proliferation and crescent formation. The glomerular-sieving method revealed that prednisolone increased p21(CIP1) expression in glomeruli. CONCLUSION: These data suggest that the cell cycle arrest of mesangial cells is mediated by a functional link between the glucocorticoid receptor and the transcriptional control of p21(CIP1) not only in vitro but also in vivo. Our observations provide new insights into the molecular mechanisms of glucocorticoid action in glomerulonephritis.

Animals↗

PubMed2001

Efficient and ligand-dependent regulated erythropoietin production by naked dna injection and in vivo electroporation.

The development of an in vivo gene transfer approach to deliver physiologic levels of recombinant proteins to the systemic circulation would represent a significant advance in the treatment of protein deficiencies-disorders. However, the ability to regulate transgene expression will become paramount for safety and efficacy in gene transfer therapy. We have described the construction of an efficient and ligand-dependently regulated erythropoietin (EPO) production system using naked plasmid and in vivo electroporation. Two plasmids, one encoding the chimeric GeneSwitch protein and the other encoding an inducible transgene for human EPO, were developed. Modulation of the level of secretion of EPO into the serum was achieved by intraperitoneal administration of mifepristone (MFP). Rats were divided into 4 groups: one group received EPO plasmid with MFP for 30 days, a second group received with EPO plasmid MFP for 9 days, a third group received EPO plasmid without MFP, and a fourth group received control plasmid. A pair of electrodes was inserted into the muscle of the right thigh and 100 micrograms of each plasmid was injected. In vivo electrporation (8 times at 100 V for 50 milliseconds) was performed. The presence of vector-derived EPO mRNA was detected by reverse transcriptase-polymerase chain reaction only in the EPO and MFP(+) group. The hematocrit levels increased continuously from the preinjection level of 42.7% to 53.8% on day 28 in the EPO and MFP(+) group. The serum EPO levels increased only in the EPO and MFP(+) group. There was no significant change in hematocrit levels and EPO levels in the EPO and MFP(-) group. These results demonstrate that EPO gene transfer with the GeneSwitch system by in vivo electroporation is a useful procedure for efficient and drug-dependent regulated delivery of EPO.

Animals↗

PubMed2000

Seasonal changes in human sleep-wake rhythm in Antarctica and Japan.

The subjects were eight men of the Japanese Antarctic Research Expedition (average age 35.8 years), and 10 healthy people living around Kofu, Japan (28.9 years). They completed a sleep log for 12 to 18 months, and the sleep-wake state was scored in 10-min epochs. Q24 values calculated by chi2 periodgram were low in the Antarctic midwinter. This means that there was difficulty in synchronizing to a 24-h period in the Antarctic midwinter. In Antarctica, sleep onset and offset times were delayed mostly in the midwinter. In Japan, sleep offset time was delayed mostly around the winter solstice.

Adult↗

PubMed1999

Validity of sleep log compared with actigraphic sleep-wake state II.

Twenty-five young people (Y group), three elderly people and seven people with various sleep disorders (SD group) kept a sleep log for 2-7 days, and their wrist-activity was monitored simultaneously. The sensitivity and specificity of the sleep log, and the ratio of agreement between the sleep log and actigraphic sleep-wake state were calculated. The sensitivity and specificity in Y group were 87.93+/-6.49% and 96.51+/-2.37%, respectively. The sensitivity in SD group was significantly lower than in Y group. Even in Y group one-hour agreement ratios dropped during the sleep onset period.

Adult↗

PubMed1998

Validity of sleep log compared with actigraphic sleep-wake state.

Seven women and 11 men, mean age 30.1 years, kept a sleep log for 5-7 days, and their wrist activity was monitored each minute. Sleep-wake state in the sleep log and actigraphic sleep-wake state were compared, and the sensitivity and specificity of the sleep log were calculated for each subject. The ratio of agreement between these two parameters was computed for each subject. The sensitivity and specificity of the sleep log were 72.73-97.56% (mean 86.71%) and 92.85-99.68% (mean 97.04%), respectively. The agreement ratio was 87.30-97.85% (93.48%), but 1-h agreement ratios from midnight dropped during the sleep onset period.

Activity Cycles↗

PubMed1998

A novel cell-free system for peptide synthesis driven by pyridine.

Previously we demonstrated that ribosomes can synthesize polypeptides in the presence of high concentrations (40-60%) of pyridine without any protein factors. Here we analyze additional ribosomal parameters in 60% pyridine using Escherichia coli ribosomes. Ribosomal subunits once exposed to pyridine failed to re-associate to 70S ribosomes in aqueous buffer systems even in the presence of 20 mM Mg2+, whereas they formed 70S complexes in the presence of 60% pyridine. Two-dimensional gel electrophoresis of ribosomal proteins revealed that some proteins located at the protuberances of the large subunit, e. g. L7/L12 and L11 forming the elongation factor-binding domain, were released in the pyridine system. The aminoglycoside neomycin, a strong inhibitor of the ribosomal (factor-independent) translocation reaction, completely blocked poly(Phe) synthesis and translocation activities in the pyridine system, whereas these activities were not affected at all by gypsophilin, a ribotoxin that inhibits factor-dependent translocation. Another inhibitor of the ribosomal translocation, thiostrepton, had no effect concerning the two activities, which is consistent with the fact that this antibiotic requires L11 for its binding to the ribosome. These results suggest that the ribosomes can perform a translocation reaction in the pyridine system, but in a factor-independent (spontaneous) manner.

Cell-Free System↗

PubMed1989

Enzyme-linked immunosorbent assay for human autoantibody to glial fibrillary acidic protein: higher titer of the antibody is detected in serum of patients with Alzheimer's disease.

We have developed an enzyme-linked immunosorbent assay (ELISA) to detect anti-glial fibrillary acidic protein (GFAP) autoantibody in human sera. The ELISA was prepared by coating microtest plates with purified GFAP from bovine spinal cord. The autoantibody activities were assayed in the serum from 219 control subjects, 39 Alzheimer's disease patients and 39 cerebrovascular dementia patients. Higher titer of the antibody was observed in the serum of Alzheimer's disease patients. Since the titer showed no significant change with aging or with sex in the control serum, we could determine a certain normal value of the antibody titer. The percentage of abnormal subjects whose antibody levels were over the normal value was 53.8% in Alzheimer's disease (presenile onset) patients, 30.8% in Alzheimer's disease (senile onset) patients, 10.3% in cerebrovascular dementia patients and 5.5% in control subjects. We discuss the relationship between the anti-GFAP autoantibody and the pathogenesis of Alzheimer's disease and suggest that the evaluation of anti-GFAP autoantibody level may be useful in diagnosing Alzheimer's disease.

Aged↗

PubMed1989