Biomedical subjects

M Ohta

Publications and source records attributed to M Ohta.

At least 739 records · Page 41Linked to original sources

PubMed1991

Successful treatment of adult Henoch-Schönlein purpura with factor XIII concentrate.

We report the cases of three adult patients with severe abdominal complications of Henoch-Schönlein purpura who had low activity of factor XIII during the acute phase of the disease. In all three cases, abdominal symptoms and purpura immediately responded to heat-treated, placenta-derived factor XIII concentrate. No adverse effects were experienced. Factor XIII concentrate replacement should be considered as the initial treatment for severe abdominal symptoms in adult Henoch-Schönlein purpura associated with a decreased level of factor XIII activity.

Acute Disease↗

PubMed1991

Developmental change in ganglioside expression in primary culture of rat neurons.

Developmental changes in ganglioside levels and patterns were investigated in neuronal cells dissociated from 17-day-old fetal rat hemispheres for up to 7 days of culture. Increases in ganglioside contents and the onset of GM3 synthesis, which is associated with proliferation of glial cells, were observed as the neuronal network was established in cell cultures. The distribution of gangliosides in developing neurons was monitored by the indirect immunofluorescent technique using three anti-ganglioside antibodies. Anti-GM1 antibody showed immunofluorescence only on the cell soma 1 and 3 days after plating and additional binding between cell aggregates by 7 days in culture. GD3 ganglioside, the predominant species in embryonic neurons, was not detected on the neuronal cell surface, whereas the number of positively stained non-neuronal cells was increased at 7 days. Monoclonal A2B5 antibody suggested that polysialogangliosides play a role in neuronal network formation. In 1-day-old culture, however, all antibodies bound poorly to cell surface antigens and strongly to cells, the membranes of which were permeabilized with acetone. These results suggest that a substantial amount of gangliosides are retained, transformed within the cell to more complex gangliosides, and translocated to the cell surface following neurite outgrowth and morphological changes.

Animals↗

PubMed1991

Inhibition by prostacyclin and carbacyclins of endothelin-induced DNA synthesis in cultured vascular smooth muscle cells.

Effects of prostacyclin and carbacyclins on endothelin-induced DNA synthesis were investigated in vascular smooth muscle cells. DNA synthesis was estimated by [3H]thymidine incorporation. Five carbacyclins used in this report were 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-3-hydroxy-1-octenyl]bicyclo [3.3.0]oct-2-en-3-yl) pentanoic acid (TEI-7165), methyl 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-3-hydroxy-1-octenyl]bicyclo[3.3.0]oct-2-en-3- yl]pentanoate (TEI-9090), 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(3S, 5S)-3-hydroxy-5-methyl-1-nonenyl]bicyclo[3.3.0]oct-2-en-3-yl)penta noic acid (TEI-9063), methyl 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(3S, 5S)-3-hydroxy-5-methyl-1- nonenyl]bicyclo[3.3.0]oct-2-en-3-yl)pentanoate (TEI-1324), 5-[(1S, 5S, 6R, 7R)-7-hydroxy-6-[(E)-(S)-4-hydroxy-4-methyl-1- octenyl]bicyclo[3.3.0]oct-2-en-3-yl] pentanoic acid (TEI-3356). Prostacyclin and the carbacyclins inhibited the endothelin-induced DNA synthesis within the nanomolar range. These results suggest that prostacyclin and carbacyclins are possibly effective in inhibiting the proliferation of vascular smooth muscle cells under some situations in vivo.

Animals↗

PubMed1991

Bovine adrenal cytochrome P-450(11 beta)-mediated conversion of 11-deoxycortisol to 18- and 19-hydroxy derivatives; structural analysis by 1H-NMR.

Incubation of 11-deoxycortisol with a cytochrome P-450(11 beta)-reconstituted system yielded, in addition to cortisol, several new steroid products. In this study, structures of the three steroid products were elucidated. Retention time of the first product (Peak 2 substance) coincided with that of authentic 18-hydroxycortisol on reverse phase HPLC. To further confirm the chemical identity of this product, the purified sample was subjected to 1H-NMR analysis. The spectrum was essentially identical to that of 18-hydroxycortisol. The retention time of the second product (Peak 3 substance) did not coincide with those of commonly occurring steroids. The one- and two-dimension 1H-NMR spectra provided strong evidence for its structure of 19-hydroxy-11-deoxycortisol. The retention time of the third product (Peak 4 substance) did not coincide with those of commonly occurring steroids. The 1H-NMR spectrum showed the presence of signals of 19-CH3 and 18-CH2 protons. There was also evidence that this product is not hydroxylated at the 11-position. Further analysis of the COSY spectra identified its structure as 18-hydroxy-11-deoxycortisol. From these results, we conclude that bovine P-450(11 beta) can catalyze the hydroxylation of 11-deoxycortisol at 11 beta-, 18- and 19-positions and produce cortisol, 18-hydroxy-11-deoxycortisol, 18-hydroxycortisol and 19-hydroxy-11-deoxycortisol.

Adrenal Cortex↗

PubMed1991

Three-dimensional structure-activity relationships and receptor mapping of N1-substituents of quinolone antibacterials.

Quantitative structure-activity relationships for quinolone antibacterials have been previously examined and a steric parameter L for the N1-substituents found to be important in QSAR equations. But some compounds for which previous QSAR equations could not predict the activity have appeared recently. In this study, conformations of a variety of N1-substituents of quinolone antibacterials were analyzed by a molecular modeling method. An active conformation of each of the compounds was estimated with information of the energy profile calculated by molecular orbital methods and of its biological activity. A model of a receptor corresponding to the N1-substituents was constructed by superposing van der Waals volumes of active conformer of highly active compounds. As a result of these conformational analyses and receptor mapping, it is proposed that there are two different optimum volumes for increasing the activity of quinolone antibacterials and two unfavorable regions for reducing the activity. It is suggested that the steric parameter L which appeared in previous QSAR equations corresponds to one of the optimum volumes of the proposed receptor model. With this receptor model, a relation between structure and activity of the compounds, including those mispredicted compounds in previous QSAR equations is able to be rationalized qualitatively and elegantly. We believe that this receptor model is useful for a prediction of the activity of compounds not yet synthesized as well as for designing new quinolone antibacterials.

4-Quinolones↗

PubMed1991

Passage and digestibility of lucerne (Medicago sativa) hay in Japanese sika deer (Cervus nippon) and sheep under restricted feeding.

The mean retention time (MRT) of stained hay through the whole digestive tract and its digestibility were measured in Japanese sika deer (Cervus nippon) and were compared with those in sheep when lucerne (Medicago sativa) hay was fed at 10, 20 and 30 g/kg body-weight. The recoveries in faeces of plastic particles with five specific gravities were also measured in deer. MRT for deer was significantly shorter than that for sheep at 10 and 20 g/kg feeding levels. The digestibilities of dry matter, organic matter, and neutral-detergent fibre were significantly lower for deer than for sheep at 30, 30 and 10 g/kg feeding levels respectively. The recovery rates of plastic particles were increased, but the ruminated rates were decreased, with increasing specific gravity in deer. These results suggest that the lower digestibility of lucerne hay in Japanese deer may be due to a shorter MRT compared with sheep.

Animals↗

PubMed1991

Aspirin test for differentiation of unilateral renovascular hypertension from hyperreninemic essential hypertension.

Responses of renin release and blood pressure to aspirin DL-lysine (ASP) were examined to find out if the responses could help in the differentiation between unilateral renovascular hypertension (RVH) and hyperreninemic essential hypertension (EHT). The two studies involved ten patients with unilateral RVH, eight with hyperreninemic EHT, and five with hyporeninemic EHT. In a radiological study, before and 30 min after an intravenous injection of ASP (18 mg/kg), renal venous and abdominal aortic plasma was sampled and assayed for prostaglandin (PG) E2 and plasma renin activity (PRA). Systemic blood pressure was measured serially. The reproducibility of the responses to ASP was confirmed in a bedside study. In unilateral RVH, ASP suppressed renin release from the stenotic kidney and reduced the renal vein PRA ratio to less than 1.5 via the inhibition of PG synthesis, which is accelerated in that kidney. The mean suppression of aortic PRA at this dose of ASP was 35% in these patients, and their blood pressure decreased in proportion to the suppression of PRA. However, in the two EHT groups, ASP elevated the mean blood pressure. The renal synthesis of PGE2 was inhibited by ASP in all patients, but the suppression of PRA, while small, was significant (19% in the aorta) in the patients with hyperreninemic EHT, and not significant in patients with hyporeninemic EHT. The different responses of blood pressure and PRA to ASP between RVH and EHT were reproducible in the bedside study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

Inhibition of endothelin-1-induced DNA synthesis by prostacyclin and its stable analogues in vascular smooth muscle cells.

The effects of prostacyclin and its stable analogues on endothelin-induced DNA synthesis were investigated in cultured vascular smooth muscle cells. Aortic smooth muscle cells were obtained from male Wistar rats. In order to eliminate endothelial cells, the cells were cloned. DNA synthesis in intact cells was estimated by [3H]thymidine incorporation. Prostacyclin and its stable analogues (TEI-7165, TEI-9090, TEI-1324, TEI-3356, and TEI-9063) inhibited the endothelin-induced DNA synthesis with an IC50 of 1-30 nM. These results indicate that prostacyclin and its stable analogues are possibly effective in preventing the proliferation of vascular smooth muscle cells under some pathological situations, including atherosclerosis.

Animals↗

PubMed1991

Central effects of endothelin-1 on vasopressin and atrial natriuretic peptide release and cardiovascular and renal function in conscious rats.

In order to investigate the central effect of endothelin-1 (ET-1) on arginine vasopressin (AVP) and atrial natriuretic peptide (ANP) release and cardiovascular and renal function, either a high dose of ET-1 (3.5 ng/kg/min, HET-1) or a low dose (0.35 ng/kg/min, LET-1) was administered into the cerebral third ventricle in conscious rats. ET-1 increased the mean arterial blood pressure, but not heart rate, in a dose-related manner. LET-1 slightly stimulated AVP release, but not ANP release. HET-1 increased plasma AVP and ANP. Pretreatment with a V1-antagonist (TMeAVP) attenuated the blood pressure response to ET-1 and completely abolished increases in plasma ANP. Moreover, prazosin given i.v. completely prevented the residual pressure response. ET-1 did not significantly affect renal electrolytes and water handling. These results suggest that centrally administered ET-1 may increase the activity of the sympathetic nervous system and vasopressinergic neurons, resulting in an increase in blood pressure.

Animals↗

PubMed1991

Penetration of lysophosphatidylcholine into the dermis.

The ability of Lysophosphatidylcholine (LPC) to penetrate into the dermis and its degradation were investigated in vivo using hairless rats. Phosphatidylcholine (PC) was used as a control. Radioactively labelled LPC and PC were applied on the surface of skin, and the radioactivities of the epidermis and dermis were measured at 8, 24, and 48 hours. The recoveries of radioactive materials of LPC and PC within the area of epidermis and dermis at 8 hours were 0.21% and 0.25%; at 24 hours, 0.68% and 0.31%; and at 48 hours, 0.42% and 0.92%. No radioactivity was detected in serum. The radioactive substances which had penetrated were identified as LPC, PC, diglycerides, and free fatty acids. It was also found that topical application of LPC did not change the structure of skin as seen by microscopical examination. These findings indicate that a small amount of LPC can penetrate without the damaging skin structure and is enzymatically degraded into several lipids. Since LPC has bactericidal and antiviral activity, this substance could be an useful agent for dermatological use.

Animals↗

PubMed1991

Cloning and expression of the rfe-rff gene cluster of Escherichia coli.

We have cloned a 13 kb Escherichia coli DNA fragment which complemented the rfe mutation to recover the biosynthesis of E. coli O9 polysaccharide. Using Tn5 insertion inactivation, the rfe gene was localized at the 1.5 kb HindIII-EcoRI region flanking the rho gene. We constructed an rfe-deficient E. coli K-12 mutant by site-directed inactivation using a DNA fragment of the cloned 1.5 kb rfe gene. This also confirmed the presence of the rfe gene in the 1.5 kb region. By simultaneous introduction of both the rfe plasmid and the plasmid of our previously cloned E. coli O9 rfb into this rfe mutant, we succeeded in achieving in vivo reconstitution of O9 polysaccharide biosynthesis. From sequence analysis of the rfe gene, a putative promoter followed by an open reading frame (ORF) was identified downstream of the rho gene. This ORF coincided with the position of the rfe gene determined by Tn5 analysis and site-directed mutagenesis. Furthermore, we identified the rff genes in the 10.5 kb DNA flanking the rfe gene. We recognized at least two functional domains on this cloned rff region. Region I complemented a newly found K-12 rff mutant, A238, to synthesize the enterobacterial common antigen (ECA). Deletion of region II resulted in the synthesis of ECAs with shorter sugar chains. When the 10.5 kb rff genes of the plasmid were inactivated by either deletion or Tn5 insertion, the plasmid lost its ability to give rise to transformants of the rfe mutants.

Amino Acid Sequence↗

PubMed1991

[Bacterial survey of patients with bacteremia during the ten years (1978-1987) in Nagoya University Hospital].

We analyzed the changes of frequency of bacterial positive cases on the basis of blood cultures, clinical background and administrated antibiotics for the patients with bacteremia in Nagoya University Hospital from January 1978 to December 1987. During the ten years, the number of samples increased from 330 in 1978 to 1231 in 1987. Moreover, bacterial positive cases increased from 27 (8.2%) in 1978 to 152 (12.3%) in 1987. Organisms isolated consisted of 138 strains of coagulase negative Staphylococci (CNS), 81 Staphylococcus aureus, 60 Candida sp., 58 Escherichia coli, 47 Pseudomonas aeruginosa, and other species. During the period of 1986-1987, of the 92 patients with bacteremia, 85 patients (92.4%) had underlying diseases including leukemia, solid tumor, cardiovascular disease, diabetes mellitus or other diseases. In addition, 67 patients (73.9%) underwent intravascular catheters, urethral catheters, postoperative drainages or other prosthetic insertions. Fourteen patients died of septicemia within a week after recovery of the organism in the blood culture. The recovery rate for gram positive cocci in blood culture increased in the 1980's. It may partly be due to the prevalent use of these prosthetic insertions, and the preferable use of second and third generation cephalosporin antibiotics.

Adolescent↗

PubMed1991

[Occurrence of Escherichia coli in urinary tract infection].

Regarding P-fimbriae, K1 antigen, sero O-type and factors on the host (age, sex and morbidity) with are the pathogenic factors in E. coli, an assessment has been made as to what relations these factors have in urinary tract infection. By age, cases of P-fimbriae is seen in large numbers among pregnant women and infants but less among the people aged 16-30. A similar trend was observed regarding K1 antigen. An assessment made by sex show a trend that E. coli which carries P-fimbriae tends to emerge frequently in males. By morbidity, P-fimbriated strain was seen in many severe cases among pregnant women and infants. The fact has become evident further as a result of making an investigation with K1 antigen added. However, the result of an assessment made in adult cases showed that P-fimbriae was seen frequently in simple cystitis conversely. As the reason for P-fimbriae being observed more in males, participations of immunological stage and anatomical factors on the host side in the pathogenicity was resumed, and the main cause that P-fimbriae is seen more in severe pregnant and infantile cases was presumed to be vesicoureteral reflux. Regarding group sero O-type and morbidity, the types reported so far were detected also at our hospital, but a very interesting finding we have obtained was that the stains P-fimbriae and K1 antigen were observed in types 2, 12, 18 and 75.

ABO Blood-Group System↗

PubMed1991

[Molecular epidemiology of Vibrio cholerae O-1 from outbreak and sporadic patients in Nagoya in 1989].

Enterotoxigenic strains of Vibrio cholerae O-1 biotype eltor, isolated from three sporadic cases of cholera in Nagoya in 1989 and an outbreak of cholera in Nagoya in 1989 were analyzed for their similarities. All isolates of V. cholerae O-1 were indistinguishable in bacteriophage types, serovars, biovars and drug resistance patterns. Because the epidemiological investigation based on a primary structure of chromosomal DNA is more reliable, we isolated chromosomal DNA from these isolates and compared electrophoretic patterns of restriction endonuclease-digested DNA fragments. Furthermore, Southern hybridization of the cholera toxin gene was performed. Since no difference among six strains in these sporadic was observed, it was strongly suggested that both the independent cases and the outbreak of cholera were caused by the same strain.

Cholera↗

PubMed1991

Increased resistance to multiple drugs by introduction of the Enterobacter cloacae romA gene into OmpF porin-deficient mutants of Escherichia coli K-12.

Introduction of the romA gene cloned from Enterobacter cloacae into Escherichia coli K-12 resulted in almost complete inhibition of OmpF expression and a concomitant increase in resistance to quinolones, beta-lactams, chloramphenicol, and tetracyclines. In addition, the romA gene reduced the susceptibility to these multiple drugs even in the OmpF porin-deficient mutants of E. coli K-12. Results indicate the presence of romA-sensitive penetration pathway(s) for these multiple drugs other than the OmpF porin in E. coli.

Anti-Bacterial Agents↗

PubMed1991

Possible mechanisms underlying the slow lactose fermentation phenotype in Shigella spp.

A Southern hybridization analysis revealed that the region homologous to Escherichia coli lacZ was present on the chromosomal DNAs of beta-galactosidase-positive Shigella strains, such as Shigella dysenteriae serovar 1 and Shigella sonnei strains, whereas this region was absent from chromosomal DNAs of beta-galactosidase-negative strains of Shigella flexneri and Shigella boydii. We found that the lacY-A region was deficient in S. dysenteriae serovar 1 and believe that this is the reason for the slow fermentation of lactose by this strain. S. sonnei strains possessed the region which hybridized with E. coli lacY-A despite their slow hydrolysis of lactose. The whole lactose-fermenting region was cloned from S. sonnei and compared with the cloned lac operon of E. coli K-12. Both clones directed the synthesis of beta-galactosidase in an E. coli K-12 strain lacking indigenous beta-galactosidase activity (strain JM109-1), and we observed no difference in the expression of beta-galactosidase activity in S. sonnei and E. coli. However, E. coli JM109-1 harboring the lactose-fermenting genes of S. sonnei exhibited the slow lactose fermentation phenotype like the parental strain. S. sonnei strains had no detectable lactose permease activities. E. coli JM109-1 harboring the lactose-fermenting genes of S. sonnei had a detectable permease activity, possibly because of the multicopy nature of the cloned genes, but this permease activity was much lower than that of strain JM109-1 harboring the lac operon of E. coli K-12. From these results we concluded that slow lactose fermentation by S. sonnei is due to weak lactose permease activity.

Blotting, Southern↗

PubMed1991

Biosynthesis of Klebsiella K2 capsular polysaccharide in Escherichia coli HB101 requires the functions of rmpA and the chromosomal cps gene cluster of the virulent strain Klebsiella pneumoniae Chedid (O1:K2).

The genes determining the biosynthesis of type 2 (K2) capsular polysaccharide [3----beta Glc1,4----beta Man(1,3----beta GlcUA) 1,4----alpha Glc1----] of Klebsiella pneumoniae Chedid (O1:K2), which is highly virulent for mice, were cloned and introduced into Escherichia coli HB101 and into four noncapsulated mutants derived from K. pneumoniae reference strains of K1, K7, K9, and K28. The recombinant plasmid pCPS7B06 carried 23 kb of a chromosomal DNA fragment of strain Chedid and encoded a part of the Klebsiella cps gene cluster. However, pCPS7B06 encoded enough genetic information for the production of Klebsiella K2 capsular polysaccharide on the cell surfaces of four noncapsulated mutants of K. pneumoniae. On the other hand, both pCPS7B06 and pROJ3 carrying the rmpA gene locus derived from a resident large plasmid of Chedid were required for the biosynthesis of Klebsiella K2 capsular polysaccharide on the cell surface of E. coli HB101. The insertion inactivation analysis using Tn5 revealed that the cps gene cluster occupied more than 15 kb of the chromosome of Chedid. We conclude that rmpA, which has been known to enhance the biosynthesis of colanic acid in E. coli, is also involved in the biosynthesis of Klebsiella capsular polysaccharide in E. coli HB101.

Animals↗

PubMed1991

Expression of the cloned Escherichia coli O9 rfb gene in various mutant strains of Salmonella typhimurium.

To investigate the effect of chromosomal mutation on the synthesis of rfe-dependent Escherichia coli O9 lipopolysaccharide (LPS), the cloned E. coli O9 rfb gene was introduced into Salmonella typhimurium strains defective in various genes involved in the synthesis of LPS. When E. coli O9 rfb was introduced into S. typhimurium strains possessing defects in rfb or rfc, they synthesized E. coli O9 LPS on their cell surfaces. The rfe-defective mutant of S. typhimurium synthesized only very small amounts of E. coli O9 LPS after the introduction of E. coli O9 rfb. These results confirmed the widely accepted idea that the biosynthesis of E. coli O9-specific polysaccharide does not require rfc but requires rfe. By using an rfbT mutant of the E. coli O9 rfb gene, the mechanism of transfer of the synthesized E. coli O9-specific polysaccharide from antigen carrier lipid to the R-core of S. typhimurium was investigated. The rfbT mutant of the E. coli O9 rfb gene failed to direct the synthesis of E. coli O9 LPS in the rfc mutant strain of S. typhimurium, in which rfaL and rfbT functions are intact, but directed the synthesis of the precursor. Because the intact E. coli O9 rfb gene directed the synthesis of E. coli O9 LPS in the same strain, it was suggested that the rfaL product of S. typhimurium and rfbT product of E. coli O9 cooperate to synthesize E. coli O9 LPS in S. typhimurium.

Agglutination↗