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Biomedical subjects

Y Ohashi

Publications and source records attributed to Y Ohashi.

At least 595 records · Page 33Linked to original sources
PubMed1987

Nucleotide sequence of the PR-1 gene of Nicotiana tabacum.

A gene encoding one of the pathogenesis-related proteins, PR1a, and two related pseudogenes were isolated from Nicotiana tabacum. The cloned PR1a gene (pPR-gamma) and one of the pseudogenes (pPR-alpha) were sequenced and found to have similar structures. The sequence of pPR-gamma was quite similar to that of the cDNA clone of PR1a. The plasmid pPR-gamma did not contain an intron and had a typical promoter sequence in the 5'-flanking region.

Base Sequence↗
PubMed1987

Acute phase responses of plasma angiotensinogen and T-kininogen in rats.

Acute phase responses of plasma angiotensinogen and kininogen were studied in rats. Plasma angiotensinogen levels increased about 3-fold during the first 8 hr, and returned to normal at 48 hr, following the induction of acute inflammation by lipopolysaccharide (LPS). Plasma kininogen reached maximum levels at 48 hr following LPS administration. In adrenalectomized rats, plasma angiotensinogen levels decreased significantly, and the administration of LPS did not elevate plasma angiotensinogen levels. In contrast, plasma kininogen levels were increased by adrenalectomy, as well as by sham-operation. Dexamethasone significantly increased plasma angiotensinogen levels in adrenalectomized rats as well as in normal rats, but aldosterone did not. Plasma kininogen levels of normal rats were not changed by the administration of dexamethasone or aldosterone. From these results, it was concluded that the acute phase response of plasma angiotensinogen is mediated by glucocorticoid, but that of plasma kininogen is not.

Acute-Phase Reaction↗
PubMed1987

Involvement of leukocyte and glucocorticoid in the acute-phase response of angiotensinogen.

Plasma levels of angiotensinogen were significantly increased in rats following treatment with lipopolysaccharide (LPS). However, no such acute-phase response in the plasma angiotensinogen level was induced in hypophysectomized rats. Implantation of peritoneal exudate cells (PEC), which had been collected from rats treated with i.p. injection of LPS and glycogen, into the peritoneal cavities of normal rats also caused elevation of plasma angiotensinogen levels. No significant changes in plasma levels of corticosterone were observed in rats receiving either LPS or LPS-stimulated PEC. These results indicate that the acute-phase response of angiotensinogen is mediated by leukocytes-derived cytokine, and glucocorticoid is essential for its stimulatory effect on the hepatic production of angiotensinogen.

Angiotensin I↗
PubMed1987

Analysis of long-chain bases in sphingolipids by positive ion fast atom bombardment or matrix-assisted secondary ion mass spectrometry.

The structures of long-chain bases are expressed as [CH2C(NH2) = CHR]+ (Z+) in the positive ion mode spectra obtained on fast atom bombardment (FAB) mass spectrometry or liquid-matrix-assisted secondary ion mass spectrometry (SIMS) [Benninghoven, A., Ed. (1983) Ion Formation from Organic Solids, Springer, Berlin]. This phenomenon is common to sphingolipids in general: glycosphingolipids [see reviews by Sweeley and Nunez [Sweeley, C. C., & Nunez, H. A. (1985) Annu. Rev. Biochem. 54, 765] and Kanfer and Hakomori [Kanfer, J. N., & Hakomori, S. (1983) Handb. Lipid Res. 3]] and phosphonosphingolipids [Hayashi, A., & Matsubara, T. (1982) in New Vistas in Glycolipid Research (Makita, A., Handa, S., Taketomi, T., & Nagai, Y., Eds.) p 103, Plenum, New York], inclusive. Phytosphingosine compounds show the same type of fragmentation without additional dehydration if a neutral matrix is used. A Z+ ion is easily detected in the lower mass region (m/z 200-400) as an even mass number fragment ion, and confirmation is made by means of B/E constant and B2/E constant linked scan techniques [Boyd, R. K., & Beynon, J. H. (1977) Org. Mass Spectrom. 12, 163; Boyd, R. K., & Shushan, B. (1981) Int. J. Mass Spectrom. Ion Phys. 37, 355; Macdonald, C. G., & Lacey, M. J. (1984) Org. Mass Spectrom. 19, 55]. [Principles of linked scannings are explicitly summarized by Jennings and Mason [Jennings, K. R., & Mason, R. S. (1983) in Tandem Mass Spectrometry (McLafferty, F. W., Ed.) p 197, Wiley, New York] besides the cited literature.]

Animals↗
PubMed1987

ADP-ribosylation by type C1 and D botulinum neurotoxins: stimulation by guanine nucleotides and inhibition by guanidino-containing compounds.

We recently reported that type D botulinum neurotoxin ADP-ribosylates a specific protein of Mr 21,000 in membrane fractions of various tissues (Ohashi, Y. and Narumiya, S. (1987) J. Biol. Chem. in press). We examined similar enzyme activities in other types (types A, B, C1 and E) of botulinum neurotoxins. Of these, only type C1 toxin showed the activity similar to type D toxin and ADP-ribosylated the same Mr 21,000 protein in membranes of mouse brain. No enzyme activities were detected in type A, B and E toxins under the present experimental conditions. GTP stimulated ADP-ribosylation by the two toxins in a concentration dependent manner from 10 nM to 100 microM. The maximum stimulation was about 6 fold. GDP was 10 times less potent than GTP and achieved similar maximum at 1 mM, while GMP, ADP and ATP had little effect. Several guanidino-containing compounds dose-dependently inhibited the activities of both toxins. The IC50 values were 8.5, 14.5 and 45 mM for agmatine, L-arginine methyl ester and guanidine, respectively.

Adenosine Diphosphate Ribose↗
PubMed1987

ADP-ribosylation of a Mr 21,000 membrane protein by type D botulinum toxin.

When crude membrane fraction from bovine adrenal gland was incubated with type D botulinum toxin in the presence of NAD, a membrane protein with a molecular weight of 21,000 was specifically ADP-ribosylated. This ADP-ribosylation occurred dependent on the dose of the toxin and was abolished by prior boiling ADP-ribose transfer to the membrane protein was significantly suppressed when agmatine and L-arginine methyl ester were included in the reaction mixture. Dithiothreitol stimulated this ADP-ribosylation about 3-fold. Incubation of membrane fractions from mouse brain and pancreas with this toxin also resulted in ADP-ribosylation of a protein of the same molecular weight. These results suggested that type D botulinum toxin catalyzed transfer of an ADP-ribose moiety of NAD to the specific membrane protein common to secretory cells.

Adenosine Diphosphate Ribose↗
PubMed1987

Acute effects of isopropyl alcohol exposure on the middle ear mucosa.

Guinea pigs were exposed to 400 ppm or 5500 ppm of isopropyl alcohol (IPA) for 24 successive hours, and then middle ear mucosal samples in both proximal and distal sites to the eustachian tube were obtained for functional and morphological examinations. The ciliary activity was examined according to the photoelectric method of Ohashi and Nakai. The morphology of the middle ear lining was examined by transmission electron microscopy. The results showed that IPA at the allowable level of 400 ppm has an acute effect on the mucociliary system of the middle ear mucosa. Recovery from damage occurs within two weeks. At higher levels of exposure to IPA (more than 10 times the allowable level) moderate deterioration of the ciliary activity and severe damage of epithelial cells were observed and recovery within two weeks was not seen. It is concluded that IPA at the allowable level of 400 ppm does not cause significant middle ear disorders, but workers exposed to higher levels of IPA should be given careful otolaryngological examinations and follow-up observations.

1-Propanol↗
PubMed1987

Recovery process of tracheal mucosa of guinea pigs exposed to isopropyl alcohol.

The toxicity of isopropyl alcohol (IPA) on the tracheal mucosa was studied experimentally with special reference to the recovery process of the organ. The results showed that 400 ppm IPA has an acute effect on the mucociliary system in the tracheal mucosa, and that recovery from such degeneration can occur in 2 weeks. When functional and morphological damage was induced by a higher level (5500 ppm) of IPA, recovery did not occur in 2 weeks. The conclusion is that the present allowable level of IPA is reasonable from the viewpoint of the effects of short-term exposure to IPA on the tracheal mucosa. In addition, a higher level of IPA exposure has longer-term effects on the tracheal mucosa, and workers exposed to such a higher level of IPA vapor should be given careful otolaryngological follow-up observations.

1-Propanol↗
PubMed1987

Effects of bacterial endotoxin on the ciliary activity in the in vitro eustachian tube.

We have used a tissue culture technique and a photoelectric method to examine the direct effect of lipopolysaccharide (LPS) on the ciliary activity present in the eustachian tube. Since LPS possesses the major part of the biological activity of endotoxin, our results show clearly that LPS deteriorates the ciliary activity in a dose-response fashion: LPS does not deteriorate the ciliary activity up to 168 h if its concentration is 1 ng/ml or less; 10 ng/ml LPS can cause deterioration of the ciliary activity with extended exposure (more than 96 h); LPS can cause dysfunction of the cilia rather quickly if the concentration is 100 ng/ml or more. Our results show that the ciliary activity in the eustachian tube under clinical conditions can be affected by endotoxin.

Animals↗
PubMed1987

Classification and Structural Comparison of Full-Length cDNAs for Pathogenesis-Related Proteins.

Fourteen cDNA clones of pathogenesis-related (PR) proteins, PR1a and PR1b of tobacco were obtained and classified into six groups based on restriction enzyme maps. To assign the groups to different classes of PR1 proteins, all the clones were partially sequenced and compared with amino acid sequences of PR1a and PR1b. Two groups of these corresponded to PR1a and four to PR1b. The results indicate that there are at least two kinds of PR1a mRNAs and four kinds of PR1b mRNAs. In fact, one cDNA insert hybridized to at least six to seven DNA fragments in restriction enzyme fragments of Samsun NN genomic DNA, indicating that the PR1 protein genes exist as a multigene family in the tobacco genome. Two sequences of essentially full-length cDNAs for PR1a and PR1b were determined and compared. The coding sequences of two cDNAs share 93% homology and the deduced amino acid sequences of PR1a and PR1b precursors, which are synthesized as larger precursors containing signal peptides, are 91% homologous. The homology of mature PR1a and PR1b regions is higher than that of larger precursors, 94% in the nucleotide sequence and 93% in the amino acid sequence, whereas that of the signal peptide regions is 80 and 90%, respectively. The hydropathy patterns and the secondary structures predicted by Chou-Fasman rules are similar to tomato PR protein in the half-side of the C terminus, which suggests that the half-C terminus side is important for the function of PR1 proteins.

Journal Article↗
PubMed1987

Nasal allergen sensitivity and mucosal IgE antibodies.

Skin tests, nasal provocation tests, nasal smear tests, and serum-radioallergosorbent tests were performed on 17 patients with perennial allergic rhinitis, who had suffered nasal congestion without receiving any antiallergic treatment. After the above tests, tissue-radioallergosorbent tests (t-RAST) were conducted to determine IgE antibody levels in inferior turbinate mucosal samples taken peroperatively. The results obtained in this study suggest that the allergen sensitivity of the nasal mucosa correlates to some extent with the mucosal IgE antibody level, and that the t-RAST can provide us with objective data about nasal allergen sensitivity.

Humans↗
PubMed1987

Herpetic keratitis therapy to reduce recurrence.

Since the herpes simplex virus locates latently in the ganglia and is reactivated by certain triggers, the important problem in treatment is to prevent or reduce recurrence. The present study investigates the role of mechanical debridement in lessening the recurrence of dendritic keratitis in patients with herpetic epithelial keratitis. Group A was treated with mechanical debridement plus IDU, Group B with IDU alone. Also studied was the effect of steroid subconjunctival injection on herpetic recurrence in patients with herpetic stromal keratitis: Group C was treated with intravenous infusion of pepsin-treated gamma-globulin (PTGG) and steroid subconjunctival injection, Group D with steroid subconjunctival injection alone and Group E with intravenous infusion of PTGG alone. The recurrence rates of dendritic keratitis were 19% in Group A and 40% in Group B (average follow-up periods: 24 and 25 months). The recurrence rates of stromal keratitis were 61% in Group C, 64% in Group D, and 36% in Group E (average follow-up periods: 20, 19 and 15 months). The difference between Groups D and E was statistically significant (chi 2 test, P less than 0.05). The recurrence rates of dendritic keratitis were 18% in Group C, 21% in Group D and 7% in Group E. In conclusion, mechanical debridement tended to reduce the recurrence of herpetic epithelial keratitis and steroid subconjunctival injection to increase the recurrence of epithelial or stromal keratitis.

Administration, Topical↗
PubMed1987

Protective effect of passive immunization on herpetic retinitis of newborn rabbits.

We studied the protective effects of passive immunization with virus specific antibody in newborn rabbits inoculated subcutaneously with type 2 herpes simplex virus (HSV-2). Newborn rabbits given anti-HSV-2 antibody intraperitoneally (IP) on days 0, 2 and 4 post infection had smaller herpetic skin lesions and reduced mortality when compared to controls. In addition, the IP treatment using this schedule reduced virus growth in the skin lesions and virus dissemination, so that it decreased the frequency of herpetic retinitis. When the IP antibody administration was started at 24 hours post virus inoculation, according to the schedule days 1, 3 and 5, there was less protection; larger skin lesions, higher mortality, and greater evidence of virus dissemination. Also HSV-infected mononuclear cells (MNCs) treated with anti-HSV serum resulted in a significant reduction in the number of infected MNCs. The results of these studies suggest that anti-HSV-2 antibody contributes to protection against HSV-2 infection of skin as well as eyes, probably by inactivation of the virus locally at the skin inoculation site, and by combating the hematogenous spread of HSV-infected MNCs as well as free virus to various organs including the eye.

Animals↗
PubMed1987

The effects of aldose reductase inhibitor on the corneal endothelial morphology in diabetic rats.

Diabetic rats were produced by intravenous injection of streptozotocin. Of these, eleven rats were treated with topical instillation of 0.5% aldose reductase inhibitor (ARI), while ten received vehicle alone. The corneal endothelium of these diabetic rats was examined by specular microscopy and compared to age-matched nondiabetic rats (ten rats). Computerized morphometric analysis of individual cells demonstrated that the endothelium of the untreated diabetic rats had marked polymegathism (increased coefficient of variation in cell area) and pleomorphism (decreased percentage of hexagonal cells), as previously observed in diabetic patients. Similar endothelial changes were also noted in the ARI-treated diabetic rats, but to a significantly lesser extent. These results suggest that topically applied ARI can be effective in reducing morphologic changes of the diabetic endothelium, and that activation of the sorbitol pathway may be implicated in the etiology of such endothelial changes.

Aldehyde Reductase↗
PubMed1987

Interferon enhances the natural killer cell activity of the retinoblastoma patients to autologous retinoblastoma cells.

The cytotoxic activities of the peripheral lymphocytes prepared from two retinoblastoma patients to freshly isolated autologous tumor cells were measured using 51Cr-release assay. The retinoblastoma cells of the two patients resisted lysis by unstimulated effectors, whereas interferon(IFN)-stimulated effector cells gave a significantly higher cytotoxicity. This result implies that IFN therapy may be potent in treating high-risk retinoblastoma patients.

Cytotoxicity, Immunologic↗