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Biomedical subjects

K Okada

Publications and source records attributed to K Okada.

At least 883 records · Page 49Linked to original sources
PubMed1993

Exanthema subitum and human herpesvirus 6 infection: clinical observations in fifty-seven cases.

Exanthema subitum had been speculated to be a viral disease although its pathogen is unknown. Human herpesvirus 6 (HHV-6), first isolated in 1986, was proved by Yamanishi et al. to be the causal agent of exanthema subitum. To evaluate the role of HHV-6 as the causal agent in clinically diagnosed exanthema subitum, we tested for HHV-6 antibody in 57 infants with clinical exanthema subitum and exanthema subitum-like rash without fever. Of the 53 patients with clinical exanthema subitum 43 showed seroconversion or a significant rise in antibody titer to HHV-6, 7 were seropositive without significant rise and 3 remained seronegative. The clinical manifestations of these 43 infants with serologically confirmed HHV-6 infection were consistent with the classical characteristics of exanthema subitum. The 4 patients with atypical exanthema subitum showed significant rises in antibody titer. Our results therefore show that the majority of cases with typical clinical manifestations of exanthema subitum had HHV-6 infection. Most cases with HHV-6 infection had the typical clinical course of exanthema subitum, and a few cases might show an afebrile exanthema subitum-like rash.

Antibodies, Viral↗
PubMed1993

Trivalent cold recombinant influenza live vaccine in institutionalized children with bronchial asthma and patients with psychomotor retardation.

Twenty asthmatic children and 48 patients with severe psychomotor retardation were inoculated intranasally with trivalent cold-adapted recombinant (CR) influenza vaccine containing CR-125 (H1N1), CR-159 (H3N2) and CRB-117 (B). The vaccinees were mostly seropositive. Severe adverse reactions or asthmatic attacks were not observed, but 7 (15%) of 48 vaccinees with severe psychomotor retardation developed mild to moderate fever. Significant antibody responses in hemagglutination-inhibition tests were demonstrated in 33 (49%) vaccinees to CR-125, 20 (29%) to CR-159 and 8 (12%) to CRB-117. Two nosocomial outbreaks of influenza were observed in the subsequent winter. During an outbreak with H3N2 in one ward of severe psychomotor retardation patients, 2 (11%) of 18 vaccinees became infected compared with 10 (48%) of 21 placebo controls in the same ward (P < 0.05). In the other outbreak, with influenza B virus, 2 (14%) of 14 vaccinees and 13 (52%) of 25 controls in the ward for asthmatic children were infected (P < 0.05). The results indicate that trivalent CR vaccine is safe and effective against nosocomial outbreaks of influenza.

Adolescent↗
PubMed1993

Selective en bloc resection of osteoid osteoma of the superior articular process of the sacral spine. A case report.

Selective en bloc resection of an osteoid osteoma from the superior articular process of the sacral spine was performed, sparing the facet joint. Computed tomography was very useful, both in making a diagnosis and in facilitating precise planning of the operative procedure. The paraspinal approach readily facilitated complete excision of the tumoral nidus with minimal surgical dissection.

Adolescent↗
PubMed1993

Expressions of DNA topoisomerase I and II gene and the genes possibly related to drug resistance in human myeloma cells.

In order to clarify the mechanism of drug resistance in human myeloma cells, we investigated the expressions of DNA topoisomerase I and topoisomerase II gene and the genes possibly related to drug resistance; multi-drug resistant gene 1 (MDR-1), glutathione S-transferase class pi gene (GST-pi), by Northern blotting. Myeloma cells in eight of 15 cases prior to chemotherapy expressed topoisomerase I mRNA considerably, while the expression of topoisomerase II mRNA was detected weakly in only one of 16 myeloma patients. There was not any correlation between expression of topoisomerase I mRNA and clinical drug resistance. Significant expression of MDR-1 mRNA and P-glycoprotein was not detected in 25 cases of multiple myeloma prior to chemotherapy and even after several courses of VAD (vincristine, adriamycin and dexamethasone) therapy by Northern blotting and immunostaining using monoclonal anti-P-glycoprotein antibody (MRK-16), respectively. On the other hand, 16 of 21 myeloma cases showed significant expression of GST-pi protein and GST-pi mRNA with the various strengths, but there was no apparent correlation between GST-pi mRNA expression and clinical response. Therefore these data suggest that expression of the genes we tested may not determine the level of drug resistance in multiple myeloma, but lower or no significant expression of topoisomerase II mRNA in most myeloma cells indicates the possibility that topoisomerase II inhibitors such as VP-16 and topoisomerase II-mediated cytotoxic drugs such as adriamycin, are not so effective for the treatment of multiple myeloma.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1993

Expression of growth hormone receptor gene in rat hypothalamus.

Growth hormone receptor (GHR) mRNA-expressing cells in the hypothalamus were observed using hybridization histochemistry in adult male rats. Digoxigenin-labeled cRNA corresponding to the extracellular part of rat GHR was used as a probe. Northern blotting analysis of hypothalamic total RNA from adult male rats revealed that the 4.5 kilobase (kb) transcript of the GHR gene corresponding to the GHR messenger RNA (mRNA) predominated over the 1.2 kb transcript corresponding to GH-binding protein mRNA. GHR mRNA-containing cells were observed in the arcuate nucleus (ARC), the periventricular nucleus (PeV), ventrolateral region of the ventromedial nucleus, the paraventricular nucleus and the supraoptic nucleus. To further understand the significance of the GHR gene expression in the hypothalamus, the effect of in vivo manipulation of GH on the somatostatin (SS) gene expression in the ARC and PeV, and the GRF gene expression in the ARC was observed among adult male rats using in situ hybridization histochemistry. Ten days after hypophysectomy, the SS mRNA level in the ARC as well as PeV was significantly lower than that in the respective nuclei of sham-operated control rats, while the GRF mRNA level in the ARC was significantly higher than that in the ARC of control animals. Subcutaneous injection of recombinant human GH (0.33 mg) to hypophysectomized rats every 12 h for 5 days restored the SS mRNA level in the ARC and PeV, and reduced the GRF mRNA level in the ARC to that of control animals. The data suggest that GH directly acts on the hypothalamic PeV and ARC, and alters the gene expression of SS and GRF.

Animals↗
PubMed1993

Effects of reserpine on the content and uptake of dopamine and noradrenaline in rabbit arteries.

1. Change with time of the content and uptake of dopamine (DA) and noradrenaline (NA) in the renal, superior mesenteric and femoral arteries and abdominal aorta of rabbit after reserpine administration was examined. Endogenous DA and NA were measured by high performance liquid chromatography coupled with electrochemical detector. 2. A single dose of reserpine (3 mg/kg, i.p.) maximally depleted the endogenous DA and NA contents in the four blood vessels 24 h after the administration; the ratios of reductions were 70-90% and approximately 90% of the normal levels, respectively. The DA contents in all four vessels recovered to the normal level within 4 days after reserpine. However, NA content did not recover to the normal levels within 30 days after reserpine except in the mesenteric artery. 3. The activity of dopamine beta-hydroxylase (DBH) significantly increased in all four blood vessels 1 h after reserpine. Although the DBH activity returned to the normal level after 3 days in the mesenteric artery, it returned within 24 h in the other three vessels. 4. [3H]-Dopamine and [3H]-NA uptake were almost completely depressed 1 h after reserpine. The [3H]-NA uptake in four vessels recovered to the normal level 2-14 days after reserpine, and [3H]-DA uptake recovered after 30-45 days. Thus, the endogenous DA content in blood vessels was completely restored although DA uptake and NA content were still affected. 5. These results suggested that the recovery of stored DA after reserpine was faster than that of stored NA and the recovery of DA uptake after reserpine was slower than NA uptake.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Adenoendocrine cell carcinoma of the gallbladder: a histochemical and immunohistochemical study.

A case of adenoendocrine cell carcinoma of the gallbladder with adenomucous cells and neuroendocrine cells is reported. A histochemical and immunohistochemical study revealed that the primary tumor in the gallbladder was composed of mucus-secreting and/or argyrophil cells. Furthermore, the tumor showed a positive reaction to carcinoembryonic antigen (CEA) in all tumor cells, to chromogranin A and cytokeratin in many tumor cells, to endocrine granule constituent (EGC) in some tumor cells, and to serotonin and somatostatin in a few tumor cells. In addition, a few mucous cells showed argyrophilia and EGC-positivity in their cytoplasms. This case suggests that the adenoendocrine cell tumor is derived from endodermal stem cells as a result of bidirectional (exocrine and endocrine) differentiation.

Adenocarcinoma↗
PubMed1993

Use of the conjugate of disulphated ursodeoxycholic acid with p-aminobenzoic acid for the detection of intestinal bacteria.

The disulphate ester of ursodeoxycholyl-p-aminobenzoic acid (PABA-UCDA) was synthesised and compared with PABA-UDCA for its use in detection of intestinal bacteria. This compound, PABA-UDCA disulphate, had characters in common with PABA-UDCA in that it was deconjugated by cholylglycine hydrolase to release free PABA and bacteria that split glycocholic acid deconjugated PABA-UDCA disulphate. Further, in rat experiments urinary excretions of PABA were measured for six hours after oral administration of 15 mg PABA-UDCA disulphate. Ten control rats excreted (mean (SE) 188.2 (13.6) micrograms of PABA; 10 rats with an intestinal stagnant loop excreted more (530.1 (30.1) micrograms; p < 0.001): whereas 10 rats in each of three groups pretreated by oral administration of various antibiotics excreted less (polymixin B+tinidazole, 4.9 (1.6) micrograms; kanamycin, 31.0 (4.7) micrograms; clindamycin 40.9 (5.5) micrograms; p < 0.001). By contrast with PABA-UDCA, PABA-UDCA disulphate was not actively absorbed from any part of the small intestine in everted gut sac experiments, and showed poor recovery from bile after its intraileal instillation in rats. This indicated that PABA-UDCA disulphate is a single pass type substance in the gut and its oral administration test reflects the sum of the activities of bacteria in the small intestine and colon. The disulphate was easily soluble in water and this allowed its application in an in vitro test involving PABA-UDCA disulphate incubation with intraperitoneal pus (PABA-UDCA disulphate incubation test) from patients with peritonitis. This test was carried out on six patients with peritonitis, and the severity of bacterial peritonitis was expressed quantitatively. From the results obtained PABA-UDCA disulphate was considered a good material to detect intestinal bacteria.

4-Aminobenzoic Acid↗
PubMed1993

Effect of parenteral administration of selected nutrients and central injection of gamma-globulin from antiserum to neuropeptide Y on growth hormone secretory pattern in food-deprived rats.

Serial changes in growth hormone (GH) secretory pattern during 72 h food deprivation and in response to refeeding after 72 h food deprivation were observed in adult male Wistar rats. In addition, the effects of intravenous administration of glucose, fatty acids or amino acids and central injection of gamma-globulin from antiserum to human neuropeptide Y (NPY) on the GH secretory pattern were examined in 72 h food-deprived rats. Rats were provided with chronic indwelling right atrial cannula and serial blood specimens were withdrawn via the cannula every 10 min using an automatic blood-sampling device. The GH secretory pattern was analyzed using a Pulsar computer program. In fed rats, episodic GH secretion with an amplitude exceeding 350 ng/ml occurred at 170-min intervals and intervening trough GH levels were less than 10 ng/ml. During the 72 h food deprivation, the amplitude of pulsatile GH secretion decreased progressively without altering the pulse frequency. When 72 h food-deprived rats were refed lab chow, the pulse frequency and the pulse amplitude increased rapidly and lasted for 6-8 h. Normal pulsatile GH secretion resumed by 10-12 h after refeeding following the 72 h food deprivation. To identify the specific nutrient (i.e. glucose, fatty acids or amino acids) serving as the signal causing restoration of the central drive to GH secretion, glucose solution (2 or 6 kcal), lipid emulsion (2 or 6 kcal) or amino acid solution (2 kcal) was administered intravenously to the 72 h food-deprived rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acids↗
PubMed1993

Enhancement of intracellular sodium by vasopressin in spontaneously hypertensive rats.

The arginine vasopressin-induced increase in intracellular sodium concentration was augmented in cultured rat vascular smooth muscle cells derived from 12-week-old spontaneously hypertensive rats (SHR) compared with those from 12-week-old normotensive Wistar-Kyoto (WKY) rats. This difference was enhanced by treatment with a Na+,K(+)-ATPase inhibitor, ouabain. The calcium-free state did not affect the basal intracellular sodium concentration but completely blocked the arginine vasopressin-induced increase in intracellular sodium concentration in both cell groups. The arginine vasopressin-mobilized cytosolic free calcium was enhanced in SHR compared with WKY rats. This enhancement was diminished but not completely inhibited in the calcium-free state. Also, arginine vasopressin-produced intracellular alkalinization was augmented in SHR. Pretreatment of both cell groups with a calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide, completely blocked arginine vasopressin-induced intracellular alkalinization and increased intracellular sodium concentration. Scatchard analysis showed that the V1 receptor number of either quiescent or proliferative cells of SHR was five to seven times greater than that of WKY rats, without any change in receptor affinity. These findings therefore indicate that the arginine vasopressin-induced increase in intracellular sodium concentration is augmented in vascular smooth muscle cells of SHR mediated through the enhancement of the mobilization of cytosolic free calcium and the activity of sodium-hydrogen exchange, which depends on an increase in V1 receptor number.

Animals↗
PubMed1993

Regulation of Na,K-adenosine triphosphatase gene expression by sodium ions in cultured neonatal rat cardiocytes.

Na,K-ATPase (Na,K-pump) plays an important role in the regulation of intracellular ion composition. The purpose of this study is to determine whether Na+ regulates the levels of mRNA coding for Na,K-ATPase alpha and beta subunits in cultured neonatal rat cardiocytes. We measured intracellular Na+ levels ([Na+]i) in cardiocytes using a Na(+)-sensitive fluorescence dye (SBFI). 1 mM ouabain caused a significant increase in [Na+]i in cardiocytes; from 12.8 +/- 0.3 to 28.8 +/- 1.8 mM. Exposure of cardiocytes to 1 mM ouabain resulted in a three- to fourfold increase in alpha 1, alpha 2, and alpha 3 mRNA accumulation, and an approximate two-fold increase in beta 1 mRNA accumulation. A maximum elevation was reached at 60 min in both cases. The ouabain-induced alpha 1 mRNA accumulation was still observed in the Ca(2+)-free culture medium. Exposure of cardiocytes to 10 microM monensin in the absence of extracellular Ca2+ also resulted in a threefold increase in alpha 1 mRNA accumulation. The increased alpha 1 mRNA expression by 1 mM ouabain was associated with a fourfold increase in alpha 1 subunit protein accumulation. Transfection experiments with chimeric plasmids containing 5'-flanking sequences of alpha 1, alpha 2, and alpha 3 isoform genes and a luciferase reporter gene revealed that 1 mM ouabain caused a twofold increase in luciferase activity in each alpha system. These results suggest that Na+ directly regulates Na,K-ATPase gene expression in cardiocytes. The transfection study further supports the premise that Na(+)-responsive elements are located within the 5'-flanking sequences of each alpha isoform gene.

Animals↗
PubMed1993

Involvement of CD8+ T cells in delayed-type hypersensitivity responses against bovine leukemia virus (BLV) induced in sheep vaccinated with recombinant vaccinia virus expressing BLV envelope glycoprotein.

Delayed-type hypersensitivity responses against bovine leukemia virus (BLV) envelope glycoprotein (gp60) were induced in the skin of sheep vaccinated with recombinant vaccinia virus (RVV) expressing BLV glycoprotein. The lesions were characterized by marked infiltration of lymphocytes, slight migration of neutrophils, eosinophils, and macrophages in the dermis to hypodermis, and partial intercellular edema in the reticular layer. Immunohistochemical analysis with monoclonal antibodies demonstrated that the lymphocytic infiltrates consisted mainly of CD8+ T cells (53.7-55.8% at 48 hours post-challenge of BLV), CD4+ T cells (24.7-26.7%), and B cells (11.5-16.9%). The role of CD4+ and CD8+ T cells in suppressing BLV growth in RVV-vaccinated animals is discussed.

Animals↗
PubMed1993

Somatostatin reduces transcription of the growth hormone gene in rats.

To examine whether somatostatin (SS) exerts influences on the steady state levels of GH-releasing factor (GRF), the effect of SS on GH gene transcription was examined in rats. This approach was used because it has been shown that GRF stimulates GH gene transcription independent of GH release, and SS does not inhibit basal or GRF-stimulated GH gene transcription. Therefore, it is assumed that an effect of SS on GH gene transcription would be mediated by a change in GRF levels. Adult female Sprague-Dawley rats were provided with right atrial cannulae. Studies were performed using unanesthetized rats. Pituitary GH gene transcription was measured by transcription assay. An iv administration of antiserum to rat GRF 150 min previously significantly decreased GH gene transcription compared with that in control rats given normal goat serum. A continuous infusion of SS (300 micrograms/kg.h) via the cannula for 150 min significantly decreased GH gene transcription compared with that in control rats receiving 0.9% NaCl. When GRF (3 micrograms/kg.h) was given simultaneously with SS (300 micrograms/kg.h), GH gene transcription increased significantly compared with that in rats receiving SS infusion alone. After the withdrawal of SS infusion, GH gene transcription rapidly and significantly increased. The data suggest that SS reduces the steady state levels of GRF.

Animals↗