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T Okada

Publications and source records attributed to T Okada.

At least 613 records · Page 34Linked to original sources
PubMed1993

Placental interleukin-6 production is enhanced in intrauterine infection but not in labor.

OBJECTIVE: Because interleukin-6 is an important mediator in the host defense mechanism against infection and tissue damage, we studied the capacity of placentas with or without either labor or chorioamnionitis in the third trimester to produce interleukin-6. STUDY DESIGN: The placental blocks were cultured, and their interleukin-6 titers were measured by a bioassay. RESULTS: Placentas with labor produced a similar amount of interleukin-6 to placentas without labor. In contrast, placentas with chorioamnionitis produced much more interleukin-6 than the placentas with or without labor (p < 0.0001). CONCLUSION: Placental interleukin-6 is thus surmised to participate in potentiation of the placental and fetomaternal defense mechanisms together with placental interleukin-1 during chorioamnionitis.

Chorioamnionitis↗
PubMed1993

Direct visualization of polypeptide shell of ferritin molecule by atomic force microscopy.

The polypeptide shell of the ferritin molecule has been imaged in water by atomic force microscopy (AFM). The central dip and the quaternary structure could be observed on the surface of the ferritin molecule anchored inhomogeneously in two dimensions. These structures observed in the AFM images are quite similar to the electron density map near the top of the apoferritin viewed down from a 4-fold axis structure reported previously (S. H. Banyard, D. K. Stammers, and P. M. Harrison, 1978. Nature (Lond.). 271:282-284). It has been achieved by introducing a "self-screening effect" of the surface charges of the AFM sample (S. Ohnishi, M. Hara, T. Furuno, and H. Sasabe. 1992. Biophys. J. 63:1425-1431) and the specially sharpened stylus of AFM cantilever.

Animals↗
PubMed1993

Development of the proximal tubule of the fetal rat kidney: morphometry and ultrastructural findings.

The development of the kidney in fetal rats was investigated morphometrically and ultrastructurally. Both the length and volume of the proximal tubule increased with age. The total volume of functional glomeruli increased markedly from fetal day 20 onward. The ratio of total glomerular volume to total proximal tubular volume decreased with age and was less than 1 from fetal day 20 onward. The cells of the proximal tubule had numerous microvilli on their free surfaces and vacuoles in the apical region of the cytoplasm after fetal day 20. These findings indicate that the relative growth of the proximal tubule has exceeded that of the glomeruli by fetal day 20, and that increased filtration induces both the growth and the differentiation of the proximal tubule during development of the fetal rat kidney.

Animals↗
PubMed1993

Prevalence of risk factors for sleep apnea in Japan: a preliminary report.

A final goal of the present study is to estimate the prevalence of sleep apnea in the general population of Japan. As the first step, the detailed questionnaires were sent out to the presumably healthy subjects who underwent regular medical checkups at four hospitals in different cities of Japan. The questionnaires included queries about difficulties in initiating and maintaining sleep, habitual snoring, parasomniac symptoms, excess daytime sleepiness, any present illness, consumptions of cigarettes and alcohol and so on. A total of 3,243 replies were obtained so far (2,029 male and 1,214 female; mean age = 50 years). The results were consistent among the four hospitals, and the prevalences of risk factors were as follows: habitual snoring was reported by 12.8-16.0%, excess daytime sleepiness by 8.1-9.4% and frequent awakenings by 7.3-12.6%, respectively. The prevalence of systemic hypertension ranged from 5.3% to 12.9%. Polysomnographic studies are being performed on the possible cases of sleep apnea who were sorted out by the questionnaires.

Adult↗
PubMed1993

Mental health in family members living with elders.

We assessed the mental health conditions of 217 subjects who took care of elders at home, using our depression scale by the surveillance of the elders living at home in Ibaraki Prefecture. An analysis was made on how depression in the caretakers was related with each item of demographical results of the caretakers and the elders living together at home, and with ADL, depression, dementia, personality change and the personality trait of the elders. Our study revealed that depression, personality change and the viscous character of the elders are three factors associated with depression in the female caretakers. Furthermore, we pointed out the necessity of an education campaign to provide the caretakers with information on the elders' personality and personality change for maintenance of the good mental health of the caretakers living with the elders.

Adolescent↗
PubMed1993

Assessment of body composition measured by bioelectrical impedance in children.

Bioelectrical impedance methods have been found to be a valid and reliable way of estimating per cent body fat (%BF) in adults. We applied them to healthy children and compared them with conventional anthropometry methods. One thousand two hundred and sixteen children participated in this study. Impedance and skinfold thickness were measured, and %BF was estimated using these values. Bodyweight and height were measured, and per cent obesity (%OB) and body mass index (BMI) were obtained. The values of %BF by the bioelectrical impedance method (%BFi) were 8.6 +/- 4.0% in the junior male group, 14.2 +/- 2.8% in the junior female group, 7.9 +/- 4.7% in the senior male group and 16.1 +/- 2.9% in the senior female group. The %BFi correlated strongly with skinfold thickness, %OB and BMI. Thus %BFi correlated strongly with variables from conventional methods. It was concluded that it is a reliable way of assessing lipid storage in children.

Adolescent↗
PubMed1993

Induction of endothelium-dependent relaxation in the rat aorta by IRL 1620, a novel and selective agonist at the endothelin ETB receptor.

1. The effects of a novel and selective agonist at the endothelin ETB receptor, IRL 1620 (Suc-[Glu9, Ala11,15] endothelin-1 (8-21)), were examined in the isolated aorta of the rat. 2. IRL 1620 (1-300 nM) changed neither the resting tone nor the cytosolic Ca2+ level ([Ca2+]i) of the aorta without endothelium. In the presence of endothelium, however, IRL 1620 increased endothelial [Ca2+]i with little effect on the muscle tone. In the absence of external Ca2+, IRL 1620 still induced a transient increase in endothelial [Ca2+]i. 3. Noradrenaline (100 nM) increased both muscle [Ca2+]i and tension. IRL 1620 (1-300 nM) relaxed the muscle with an increase in endothelial [Ca2+]i only in the presence of endothelium. An inhibitor of nitric oxide synthase, 100 microM NG-monomethyl-L-arginine, inhibited the relaxant effect of IRL 1620 but not the increase in endothelial [Ca2+]i. 4. In resting and noradrenaline-stimulated aorta, the effects of IRL 1620 were inhibited by a selective antagonist of the ETB receptor, IRL 1038 (0.3-3 microM), although a selective antagonist of the ETA receptor, BQ-123 (3 microM), was ineffective. Verapamil (10 microM) did not alter the effects of IRL 1620. 5. A muscarinic receptor agonist, carbachol (1 microM), also induced endothelium-dependent relaxation with an increase in endothelial [Ca2+]i. However, the effects of carbachol were not inhibited by the ETB antagonist, IRL 1038 (3 microM). 6. These results suggest that IRL 1620 is a selective agonist at the ETB receptor which increases endothelial [Ca2+]i by releasing Ca2+ from storage sites and by opening non-L type Ca2+ channels,activates nitric oxide synthase, releases nitric oxide, and relaxes vascular smooth muscle.

Animals↗
PubMed1993

[Clinical study of patients with deep-seated fungal infection associated with hematological diseases].

An assessment has been made regarding usefulness of measuring beta-D-glucan (beta-glucan) as fungal serodiagnosis in 50 cases of fungal infection with hematological diseases. Further, an assessment has been made regarding relation between hematological findings and therapeutic effect by administering miconazole, an antifungal agent (MCZ: Florid, clinically to the subjects. Positivity of beta-glucan (beta-glucan > or = 10 pg/ml) was observed in 54.5% (24/44), and the effective rate of MCZ in the positive cases was 75.0% (18/24). In the cases in whom fungus was detected, beta-glucan-positive rate was 50.0% (8/16), and MCZ-effective rate in beta-glucan-positive cases was 62.5% (5/8). The total effective rate of MCZ was 80% (40/50). Side effects were observed in 3 cases, but continual administration of MCZ was possible in all of the 3 cases. By the assessment regarding the relation between hematological findings and therapeutic effect of MCZ, it was found that the effective rates in the cases who underwent a transition with neutrophil and lymphocyte counts less than 500/microliters during the period of MCZ administration were 64.7% (11/17) and 50% (5/10), respectively, and large effects were observed in the cases who underwent a transition with the neutrophil and lymphocyte counts more than 500/microliters was 86.7% (19/22) and 91.7% (22/24), respectively. These results suggested that lymphocytes rather than neutrophils had an important role in the morbidity of fungal infection. It was noteworthy that MCZ was effective for the treatment of deep seated mycosis and significant effective rate was obtained in the group of patients who had neutrophils and lymphocytes less than 500/microliters.

Adolescent↗
PubMed1993

Production, characterization, and application of monoclonal antibodies which distinguish three glucosyltransferases from Streptococcus mutans.

Thirty-three murine monoclonal antibodies (MAbs) against the three glucosyltransferases (GTFs) (GTF-I, -SI, and -S) from Streptococcus mutans were obtained by the fusion of murine myeloma cells (P3X63-Ag8-U1) with spleen cells of BALB/c mice immunized with pure GTF-S or partially purified GTF-I from serotype c S. mutans PS14. The immunoreactivities of these MAbs were tested by enzyme-linked immunosorbent assay and Western blotting (immunoblotting) with various GTF preparations. GTF-I and GTF-SI were expressed from two Streptococcus milleri or Escherichia coli transformants harboring gtfB or gtfC, respectively. All of the five MAbs raised against the GTF-S from PS14 reacted only with the homologous enzymes. Of these, 8 MAbs reacted only with the gtfB gene product (GTF-I), 4 MAbs reacted only with the gtfC gene product (GTF-SI), and the remaining 16 MAbs reacted with both gene products. The existence of GTF-SI in the purified GTF-I from PS14 was demonstrated by Western blot analysis using the representative monospecific MAbs. Further, the relative levels of the three GTFs in the extracellular and cellular fractions of S. mutans clinical isolates were examined by immunoblot analysis. The findings indicated that the relative level of GTF-SI, unlike that of GTF-I or GTF-S, differed markedly among isolates although the three GTFs were synthesized extracellularly by all the strains.

Animals↗
PubMed1993

Antibody mimicking the action of RAS proteins on yeast adenylyl cyclase: implication for RAS-effector interaction.

Polyclonal antisera were raised against various subregions of Saccharomyces cerevisiae adenylyl cyclase in order to examine the molecular mechanism of interaction between adenylyl cyclase and RAS proteins. One of the antisera was found to activate adenylyl cyclase to an extent comparable to that activated by saturating amounts of yeast RAS2 protein produced in Escherichia coli. The stimulatory effect of this antiserum was shown to be additive with RAS2 protein when both antisera and RAS2 protein were present at low concentrations. At saturating amounts of RAS2 protein, the antisera did not exhibit additional stimulatory effects, suggesting that the actions of RAS2 protein and the antisera are complementary with each other. The antigenic determinant for the antibody involved in the activation was mapped to a 14-amino-acid segment, 1452-NSVDNGADVANLSY-1465, located between the leucine-rich repeats and the catalytic domain of adenylyl cyclase. Certain missense mutations affecting this 14-amino acid segment significantly reduced the response of adenylyl cyclase to both activating antibody and RAS proteins. These results suggest that this segment of adenylyl cyclase is intimately involved in the mechanism by which RAS proteins activate this downstream effector.

Adenylyl Cyclases↗
PubMed1993

Diffuse proliferative glomerulonephritis with hepatitis C virus-like particles in paramesangial dense deposits in a patient with chronic hepatitis C virus hepatitis.

A 62-year-old man with hepatitis C virus (HCV) infection developed proliferative glomerulonephritis with IgM and C3 deposits. Electron microscopy showed HCV-like particles in the paramesangial dense deposits, which are similar in shape to HCV previously described. These findings suggest HCV-related proliferative glomerulonephritis.

Chronic Disease↗
PubMed1993

Perinatal development of Brunner's glands in the rat: morphometrical study.

Perinatal changes of the Brunner's glands in rats from fetal day 20 through neonatal day 3 were studied morphometrically and electron-microscopically. Percentage volume of secretory granules of the gland cells did not change from fetal day 20 through neonatal day 1 and increased significantly from neonatal days 1-2; this level was maintained through neonatal day 3. Electron-microscopically, the gland cells during the fetal days were rich in free ribosomes. The Golgi apparatus and rough-surfaced endoplasmic reticulum (RER) were poorly developed during fetal days. After birth, however, the cells showed active formation of secretory granules, which was evidenced by well-developed Golgi apparatus, distended RER and accumulation of granules in the apical cytoplasm. Furthermore, light microscopy revealed that strongly PAS-positive material increased for the first time after birth, indicating remarkable formation of the secretory granules. Thus, the present study indicates that the cell of the Brunner's glands become active in secretory granule formation just after birth by responding to ingested material following birth.

Animals↗
PubMed1993

The interleukin-6 (IL-6)/IL-6-receptor system induces human chorionic gonadotropin production by activating tyrosine kinase-dependent signal transduction pathway different from pathways triggered by protein kinase activators including gonadotropin releasing hormone.

Interleukin-6 (IL-6) may play an important role in human CG (hCG) production by activating the IL-6-receptor (-R) system on human trophoblasts. Trophoblasts produced hCG in response to rIL-6 as well as to 8-bromo cAMP (8-Br-cAMP), 12-O-tetradecanoyl phorbol-13-acetate (TPA), and calcium ionophore A23187. To determine whether the signal transduction pathway activated by the IL-6-R system depends on protein kinases such as protein kinase A, protein kinase C, and Ca2+/calmodulin-dependent kinase, trophoblasts were stimulated with recombinant (r-) IL-6 in the presence or absence of protein kinase inhibitors such as N(2-methyl-aminoethyl)-5-isoquinoline sulfonamide dihydrochloride (H8), and 1-(5-isoquinolinesulfomyl)-2-methylpiperazine (H7) and a calmodulin antagonist, N-(6-aminohexyl)-5-chloro-1- napthalenesulfonamide (W7), H8, H7, and W7 failed to suppress rIL-6-induced hCG production but completely inhibited hCG production induced by 8-Br-cAMP, TPA, and the GnRH agonist (GnRHa), respectively. In contrast, genistein, a tyrosine kinase inhibitor, completely suppressed rIL-6-induced hCG production but failed to inhibit hCG production induced by 8-Br-cAMP, TPA, and A23187. Genistein also did not suppress GnRH-induced hCG production. The addition of genistein to rIL-1- and rTNF-alpha-stimulated trophoblasts inhibited rIL-1-induced and rTNF-alpha induced hCG production but maintained rIL-1- and rTNF-alpha-induced IL-6 production. These results show that the IL-6/IL-6-R system-induced signal transduction pathway in the placenta probably stimulates hCG production by activating a tyrosine kinase pathway. The experiment with genistein shows that the GnRH/GnRH-R system activates a signal transduction pathway distinct from that activated by the IL-6/IL-6-R system.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1993

Quantitative structure-activity relationships of antibacterial agents, 7-heterocyclic amine substituted 1-cyclopropyl-6,8-difluoro-4-oxoquinoline-3-carboxylic acids.

Quantitative structure-activity relationships (QSAR) of various 7-(3-substituted-azetidin-1-yl)-1-cyclopropyl-6,8-difluoro-1,4-dih ydro-4- oxoquinoline-3-carboxylic acids, 14-25, were studied to clarify the structural requirements for 3-substituted azetidines to potentiate antibacterial activity. A good parabolic relationship seemed to exist between the relative mean antibacterial activity indices against five representative gram-negative bacteria, GNM, and the calculated hydrophobic parameters, CLOG P, of these molecules. The CLOG P value of the most potent derivative was predicted to be around 2.3. On the other hand, against five representative gram-positive bacteria, the relative mean antibacterial activity indices, GPM, remained high and rather constant regardless of structural variation in the azetidine moiety. In order to confirm these findings, the QSAR analysis was extended with success to the quinolonecarboxylic acids, 26-34, which bear various substituted pyrrolidine, piperazine and piperidine derivatives instead of azetidines. The findings showed that the introduction of any amide substituent group to these heterocyclic amine moieties would lead to marked decrease in GNM, whereas incorporation of some amino substituent groups at a position two or three carbons remote from the N-1 position resulted in great enhancement of GNM. As azetidine quinolones exhibited somewhat low in vivo antibacterial activities, possibly reflecting their lesser bioavailability, we finally selected 3-amino-4-methoxypyrrolidine as one of the most promising C-7 substituent groups based on our QSAR analysis.

Anti-Bacterial Agents↗
PubMed1993

Synthesis and structure-activity relationships of 7-(3'-amino-4'-methoxypyrrolidin-1'-yl)-1-cyclopropyl-6,8-difluoro-1,4- dihydro-4-oxoquinoline-3-carboxylic acids.

A new series of quinolone derivatives 3a--1 bearing 3-amino-4-methoxypyrrolidines of different configurations and chirality were synthesized and their antibacterial activities as well as some of their toxicological properties were examined. As predicted by our previous quantitative structure-activity relationships (QSAR) analysis of C-7 heterocyclic amine substituted quinolonecarboxylic acid antibacterial agents, these pyrrolidine derivatives showed higher in vitro and in vivo antibacterial activities against both gram-positive and gram-negative bacteria than the analogs bearing various 3-substituted azetidines. Furthermore, the amino and methoxy substituent groups on the pyrrolidine ring exhibited strong configurational and chiral effects on the in vitro and in vivo antibacterial activities of these compounds: (1) cis compounds showed higher antibacterial activities against most of the pathogens examined; (2) N-methylation of the 3-amino group on the pyrrolidine ring lowered in vitro but not in vivo antibacterial activities, particularly leading to superior in vivo anti-pseudomonal activity; (3) the (3'S,4'R)-derivative showed substantially higher activity that the (3'R,4'S)-one. These findings led to the selection of compound 3k for further evaluation as it possessed the highest in vivo antibacterial activity and no cytotoxicity.

Anti-Bacterial Agents↗