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Biomedical subjects

A Ohta

Publications and source records attributed to A Ohta.

At least 217 records · Page 12Linked to original sources
PubMed1992

Development of physical dependence on morphine not accompanied with tolerance formation.

The development of tolerance induced by daily repeated administration of 10 mg/kg of s.c. morphine was suppressed by combined injection of adrenergic blockers, 10 mg/kg i.p. phentolamine or propranolol, in mice. However, this treatment could not prevent the development of physical dependence as evidenced by the naloxone precipitated abstinence signs. Thus, we provide a new evidence that morphine analgesia, tolerance and physical dependence is dissociable from each other.

Analgesia↗
PubMed1992

Partial sequence of acid phosphatase-1(1) gene (Aps-1(1)) linked to nematode resistance gene (Mi) of tomato.

A partial amino acid sequence of acid phosphatase-1(1) (apase-1(1)), one of acid phosphatase isozymes of tomato, was identified. This information enabled us to synthesize degenerated primer pools of oligonucleotides for polymerase chain reactions (PCR) using cDNA for poly(A)+ RNA of tomato leaves as a template. As a result, a 135-bp, then a 467-bp PCR product were obtained. Nucleotide sequencing of these two PCR products gave a total of 522-bp sequence that was identified as a part of the Asp-1(1) gene judging from the amino acid sequence deduced from it. Using the 135-bp PCR product as a probe, we detected the restriction fragment length polymorphism (RFLP) in two different lines of tomato by genomic Southern blot analysis. We also did pulsed-field gel electrophoresis (PFGE) and Southern blot analysis to search for suitable fragments to clone into a YAC vector. As a result, a single band with a size that could be cloned into a YAC vector was detected when the genomic DNA was digested with some kinds of restriction enzymes.

Acid Phosphatase↗
PubMed1992

Genetic analysis of systemic lupus erythematosus: association with a T cell receptor restriction fragment length polymorphism in Japanese patients.

Many studies have suggested the involvement of multiple genetic loci in the development of systemic lupus erythematosus (SLE). We have analyzed the correlation between various genetic markers and the susceptibility to SLE. In this study, the association of SLE and restriction fragment length polymorphism (RFLP) of T cell receptor gene was evaluated. The cDNA for constant regions of alpha, beta and gamma chain were used as probes and RFLPs were analyzed after digestion with Eco RI, Bam HI, Pst I, Pvu II, Hind III and Bgl II. Among them, polymorphisms were detected using Bgl II- and Hind III-digested DNA and C beta as a probe. Association with SLE in Japanese patients was found only after digestion with Hind III. The absence of the 13 kb polymorphic band appeared to be correlated with the development of SLE (relative risk = 4.78).

Blotting, Southern↗
PubMed1992

Cholesterol polyp of the gallbladder showing rapid growth and atypical changes--a case report.

We report on a case of resected cholesterol polyp with typical ultrasonic findings that became atypical, with a 40% increase in diameter, over a period of about 10 months. The resected specimen revealed a black polyp with a large-nodular appearance. The pathological diagnosis was cholesterol polyp with marked glandular proliferation, and the glandular cavity showed cystic dilatations filled with dark brown fluid. It is suspected that the aggregation of large numbers of these dilated glands explained the black color, the rapid growth, and the development leading to the atypical ultrasonic findings.

Adult↗
PubMed1992

Preliminary criteria for classification of adult Still's disease.

We have attempted to design classification criteria for adult Still's disease by analyzing the data obtained through a multicenter survey of 90 Japanese patients with this disease and of 267 control patients. The proposed criteria consisted of fever, arthralgia, typical rash, and leukocytosis as major, and sore throat, lymphadenopathy and/or splenomegaly, liver dysfunction, and the absence of rheumatoid factor and antinuclear antibody as minor criteria. Requiring 5 or more criteria including 2 or more major criteria yielded 96.2% sensitivity and 92.1% specificity. However, an exclusion process will be needed for an accurate classification, since this disease is relatively rare.

Adolescent↗
PubMed1992

Effects of 2,5-dimethylpyrazine on reproductive and accessory reproductive organs in female rats.

The effects of 2,5-dimethylpyrazine on reproductive and accessory reproductive organs in female rats were studied. Following the administration of 2,5-dimethylpyrazine, uterus weight was significantly decreased while ovary weight was not affected, nor was there any influence on serum level of estradiol. The increase of uterine weight observed following estradiol injection after ovariectomy was inhibited by 2,5-dimethylpyrazine pretreatment. The uptake of 3H-estradiol into the uterus was also significantly decreased by 2,5-dimethylpyrazine. On the other hand, chlorpromazine administration resulted in significant decrease in ovary and uterus weight as well as serum estradiol level. These results suggest that 2,5-dimethylpyrazine may have direct inhibitory action on the uterus of rats.

Animals↗
PubMed1991

Calcium-sensitive cls mutants of Saccharomyces cerevisiae showing a Pet- phenotype are ascribable to defects of vacuolar membrane H(+)-ATPase activity.

Ca(2+)-sensitive mutants of the yeast Saccharomyces cerevisiae showing a Pet- phenotype (cls7-cls11) have lesions in a system for maintaining intracellular Ca2+ homeostasis (Ohya, Y., Ohsumi, Y., and Anraku, Y. (1986) J. Gen. Microbiol. 132, 979-988). Genetic and biochemical studies have demonstrated that these Pet- cls mutants are related to defects in vacuolar membrane H(+)-ATPase. CLS7 and CLS8 were found to be identical with the structural genes encoding subunit c (VMA3) and subunit a (VMA1), respectively, of the enzyme. In addition, these five mutants all had vma defects; no vacuolar membrane ATPase activity was detected in the cls cells, and the cls mutants showed a loss of ability to acidify the vacuole in vivo. Measurements of the cytosolic free Ca2+ concentration [( Ca2+]i) in individual cells showed that the average [Ca2+]i in wild-type cells was 150 +/- 80 nM, whereas that in five Pet- cls cells was 900 +/- 100 nM. These data are consistent with the observation that vacuolar membrane vesicles prepared from the Pet- cls cells have lost ATP-dependent Ca2+ uptake activities. The cls defects of vacuolar membrane H(+)-ATPase resulted in pleiotropic effects on several cellular activities, including Ca2+ homeostasis, glycerol metabolism, and phospholipid metabolism. The mutants showed an inositol-dependent phenotype, possibly due to alteration in regulation of phospholipid biosynthesis; the phosphatidylserine decarboxylase activities of the mutants were 15-50% of that of the wild-type cells and were not repressed by the addition of inositol. In contrast to the majority of previously isolated pet mutants (Tzagoloff, A., and Dieckmann, C. L. (1990) Microbiol. Rev. 54, 211-225), the Pet- cls mutants showed no detectable mitochondrial defects. Taking all these findings into account, we suggest that at least six genes, VMA1 (CLS8, subunit a), VMA2 (subunit b), VMA3 (CLS7, subunit c), VMA11 (CLS9), VMA12 (CLS10), and VMA13 (CLS11), are required for expression of the vacuolar membrane H(+)-ATPase activity.

Aerobiosis↗
PubMed1991

Vascular effects of tetramethylpyrazine: direct interaction with smooth muscle alpha-adrenoceptors.

The interaction of tetramethylpyrazine, a vasoactive ingredient of a Chinese traditional medicinal plant, with the vascular muscle alpha 1-adrenoceptors was investigated by a direct radioligand binding technique using [3H]prazosin and vascular smooth muscle microsomes isolated from dog aorta and mesenteric artery. Tetramethylpyrazine inhibited the binding of [3H]prazosin to vascular muscle membranes in a concentration-dependent manner at a suboptimal concentration of prazosin. Scatchard analysis of the effect of tetramethylpyrazine on the saturation profile of [3H]prazosin binding to vascular muscle microsomes of either arterial muscle indicated a substantial increase of Kd values (the affinity for prazosin) without a change in Bmax (maximal binding sites for prazosin). Thus, the present results provide supporting evidence that the inhibitory effect of tetramethylpyrazine on the vasoconstriction of dog mesenteric artery induced by phenylephrine in the earlier studies may be, at least, in part due to a direct action at the recognition sites of alpha 1-adrenoceptors. Amiloride and amiloride-related compounds, which shares a common pyrazine ring structure with tetramethylpyrazine and other related derivatives, also inhibits the binding of [3H]prazosin to aortic muscle microsomal membranes. Functional studies of dog saphenous vein also indicated that both tetramethylpyrazine and its ethyl derivatives inhibited the responses induced by phenylephrine and B-HT 920 in the presence and absence of extracellular Ca2+. Together with our earlier findings that amiloride also inhibits [3H]prazosin and [3H]rauwolscine binding to vascular muscle alpha 1- and alpha 2-adrenoceptors, the present radioligand binding study in canine arteries and functional study in saphenous veins suggest that the above compounds containing the pyrazine nucleus indeed interacted at the alpha-adrenoceptor sites.

Adrenergic alpha-Agonists↗
PubMed1991

Effects of the mammalian lignan, 2,3-dibenzyl-butane-1,4-diol, on contraction and Ca2+ mobilization induced by noradrenaline in rat aorta.

1. In rat aorta, 2,3-dibenzylbutane-1,4-diol (DBB) inhibited noradrenaline (NA)-induced contraction in a concentration-dependent manner. The inhibitory effect of DBB was observed in verapamil-pretreated muscle, and did not differ from that in the high K+ solution containing verapamil (1.0 microM). 2. DBB inhibited not only contraction, but [Ca2+]i elevation induced by NA (10 microM) with the same potency. 3. The inhibitory effect of DBB on NA-induced contraction was reversed by methylene blue (3.2 microM) and enhanced by M&B 22,948 (10 microM). 4. DBB (100 microM) alone increased cyclic GMP levels. This effect was attenuated by methylene blue (3.2 microM) and augmented by M&B 22,948 (10 microM). 5. From these results, the inhibitory effects of DBB on NA-induced contraction in rat aorta may be caused by an increase of cyclic GMP levels.

Animals↗
PubMed1991

Amplification and substantial purification of cardiolipin synthase of Escherichia coli.

A simple, specific, and sensitive assay procedure for cardiolipin synthase of Escherichia coli has been developed. This measures the radioactivity of glycerol formed from phosphatidyl [2-3H]glycerol and is mainly based on the findings that 400 mM phosphate and 0.015% Triton X-100 markedly activate the enzyme. Cardiolipin synthase was amplified 760-fold upon induction with isopropyl beta-D-thiogalactoside in cells harboring a pBR322 derivative in which the cls gene encoding this enzyme was preceded by the tac promoter. Under these conditions, cardiolipin content increased, membrane potential decreased, spheroplasts became fragile, cells lost viability, and inducer-resistant mutants appeared at a high frequency. The amplification enabled the isolation of an enzyme preparation with a specific activity approximately 10,000-times higher than that of wild-type whole cell lysate. This purification was simply achieved by extraction of the crude membrane fraction with Triton X-100 and a single phosphocellulose column chromatography. This preparation, together with the crude envelope fraction, was used to characterize the basic properties of E. coli cardiolipin synthase, some of which were utilized in setting up the assay conditions.

Detergents↗
PubMed1991

Intraocular microdialysis with permanently implanted probes in rabbit.

The technique of microdialysis in vivo, much used in brain experiments, has been adapted for intraocular use. A new probe was designed, made from a soft tube with the dialysis membrane mounted in a fenestrated protecting sleeve, facing one side. A special surgical procedure was developed for the long-term implantation of the probes. They stay functional in the eyes for several weeks or more. Previously published intraocular microdialysis studies were short-term experiments. The acute surgical trauma is likely to affect the concentration of many compounds in the vitreous, and this effect is minimized with long-term probes.

Amino Acids↗
PubMed1991

In vitro and in vivo antifungal activities of BMY-28864, a water-soluble pradimicin derivative.

BMY-28864, a water-soluble pradimicin derivative, had potent in vitro activity against a wide variety of fungi, including those associated with deep-seated mycosis; it inhibited the growth of standard strains and clinical isolates at concentrations of 12.5 micrograms/ml or less. At the MIC or higher concentrations, BMY-28864 was fungicidal for Candida albicans under both growing and nongrowing conditions. BMY-28864 expressed fungicidal activity only in the presence of Ca2+, and its activity was totally diminished when ethylene glycol-bis(2-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA), a Ca2+ chelator, was added to the test medium. The effectiveness of intravenously administered BMY-28864 in vivo was examined and compared with that of amphotericin B in mouse models of fungal infections. Both normal and cyclophosphamide-treated immunosuppressed mice infected with C. albicans, Cryptococcus neoformans, or Aspergillus fumigatus responded to therapy with BMY-28864 (50% protective doses of 17, 18, and 37 mg/kg of body weight in normal mice and of 32, 35, and 51 mg/kg in cyclophosphamide-treated mice, respectively). Lethal lung infections were also established with C. albicans or A. fumigatus in cyclophosphamide-treated mice. The 50% protective doses of BMY-28864 were 15 and 23 mg/kg per dose against C. albicans and A. fumigatus, respectively. The immunosuppression induced by intraperitoneal administration of 200 mg of cyclophosphamide per kg lasted for 5 days, and total recovery was observed by day 7.

Amphotericin B↗
PubMed1991

Inhibitory effects of tetramethyl and tetraethyl derivatives of pyrazine on dog saphenous vein.

The effects of two structurally similar pyrazine derivatives, tetramethylpyrazine (TMP) and tetraethylpyrazine (TEP) on the contractile responses of dog saphenous vein to KCl (via membrane depolarization), phenylephrine (PHE, alpha 1-adrenergic agonist), and B-HT 920 (alpha 2-adrenergic agonist) were investigated. The relaxant or inhibitory effect of TMP and TEP was most potent on KCl-induced responses and least potent on PHE-induced responses. Their effect on KCl-induced responses was more prominent at 30 mM KCl than at 100 mM KCl. In Ca(2+)-free medium, PHE and B-HT 920 elicited transient responses, which were also markedly and reversibly inhibited by TMP and TEP. Similar results were also obtained when prostaglandin F2 alpha was used as an agonist. In all four types of contractile responses involving different receptors, the inhibitory effect of TEP was consistently more potent than that of TMP. We conclude that both TMP and TEP behave as a nonselective smooth muscle relaxant having similar and multiple actions including their general interference with the processes involving both Ca2+ entry and intracellular Ca2+ release.

Animals↗
PubMed1991

[Coronary vasospastic activity at sites of percutaneous transluminal coronary angioplasty: evaluation using intracoronary acetylcholine administration].

To investigate coronary vasospastic activity after percutaneous transluminal coronary angioplasty (PTCA), we performed intracoronary injection of acetylcholine in 55 patients, mean 3.3 months after successful PTCA. Coronary spasm was defined as transient total or subtotal occlusion of the PTCA sites. Sixty-nine lesions of the 55 patients were examined to determine whether spasm was provoked by incremental doses of acetylcholine. Restenosis was defined as coronary luminal narrowing of > or = 50% after nitroglycerin or isosorbide dinitrate. Twenty of the 55 patients (36%) and 23 of the 69 lesions (33%) had coronary spasm. There was no correlation between the incidence of coronary spasm and the interval from PTCA to the acetylcholine test. The spasm was provoked in 17 lesions of the 50 non-restenotic lesions (34%) and was also provoked in 6 of the 19 restenotic lesions (32%). On the other hand, restenoses occurred in 6 of the 23 spastic lesions (26%) and in 13 of the 43 non-spastic lesions (28%). There was no correlation between the incidence of coronary spasm and the occurrence of restenoses. Twenty-four patients had undergone acetylcholine provocative test before PTCA. Among these 24 patients, 11 had coronary spasm before PTCA, and 7 had coronary spasticity after PTCA. Four patients who had positive evidence of coronary spasm before PTCA did not show negative spasm after PTCA. On the other hand, 3 patients who did not show evidence of coronary spasm showed positive evidence of coronary spasm after PTCA.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1990

Isolation and characterization of three distinct 34 kDa EDTA-extractable proteins from bovine lens.

EDTA-extractable protein (EEP) is known to be a major lens membrane protein with a molecular mass in the range 32 kDa to 38 kDa, and is also known to bind to the lens membrane and phospholipid-containing liposomes in a calcium-dependent manner. Recent results (Russell, P., Zelenka, P., Martensen, J., and Reid, T.W. (1977) Curr. Eye Res. 6, 533-538) on antibody cross-reactivity have demonstrated that a 34-35 kDa component of EEP is identical to calpactin I (lipocortin II). In this study, we have identified and purified three distinct 34 kDa components of EEP (designated as EEP-34A1, EEP-34A2 and EEP-34B) from bovine lens that inhibit phospholipase A2 activity. These proteins bind to phospholipid-containing liposome and F-actin in a calcium-dependent fashion. Two-dimensional electrophoresis demonstrates that the three proteins were distinct from one another. However, immunochemical studies and one-dimensional peptide mapping indicate that EEP-34A1 and EEP-34B are very similar. Our results also indicate that EEP-34A1 is very similar to calpactin II and that EEP-34A2 corresponds to calpactin I. The bovine lens 34-35 kDa component of EEP is a mixture of proteins rather than a single protein.

Actins↗
PubMed1990

Identification of the 32 kDa components of bovine lens EDTA-extractable protein as endonexins I and II.

EDTA-extractable protein (EEP) is a mixture of major lens membrane proteins with molecular masses ranging from 32 kDa to 40 kDa. These bind to the lens membrane in a Ca2(+)-dependent manner. In the present study we have identified and purified two distinct 32 kDa components of EEP (designated as EEP 32-1 and EEP 32-2) from bovine lens that inhibit phospholipase A2 activity. Both EEP 32-1 and EEP 32-2 bind to phospholipid-containing liposomes and actin filaments in a Ca2(+)-dependent fashion. Immunochemical studies and two-dimensional electrophoreses demonstrate that the two proteins are distinct from one another. Both EEP 32-1 and EEP 32-2 are clearly different from calpactin (lipocortin) or its proteolytic fragments because they did not react with anti-[human placenta calpactin (lipocortin)] antibody. Our results also indicate that EEP 32-1 is very similar to endonexin I and that EEP 32-2 corresponds to endonexin II.

Actins↗