Biomedical subjects

T Adachi

Publications and source records attributed to T Adachi.

At least 271 records · Page 15Linked to original sources

PubMed1996

Mitogen-activated protein kinase activation in hepatocyte growth factor-stimulated rat hepatocytes: involvement of protein tyrosine kinase and protein kinase C.

Hepatocyte growth factor (HGF) stimulated mitogen-activated protein (MAP) kinases and MAP kinase kinase in primary cultured rat hepatocytes. Inhibitors for protein kinase C (PKC), Ro31-8425, H-7, and calphostin C, reduced HGF-induced MAP kinase activity. A PKC activator, phorbol myristate acetate (PMA), induced MAP kinase activation in a concentration-dependent manner. Protein tyrosine kinase (PTK) inhibitors, genistein, and ST638 also inhibited HGF-induced MAP kinase activation. Furthermore, HGF increased formation of Ras guanosine triphosphate (GTP) complex, indicating Ras activation. Genistein inhibited HGF-induced Ras activation, but Ro31-8425 was without effect. On the other hand, Ro31-8425 decreased HGF-induced [3H]arachidonic acid (AA) release and [3H]thymidine incorporation. Genistein also prevented [3H]AA release and [3H]-thymidine incorporation. Moreover, a commonly used phospholipase A2 (PLA2) inhibitor, quinacrine, decreased HGF-induced [3H]AA release and [3H]thymidine incorporation. The inhibitory profile of [3H]AA release was well correlated with that of [3H]thymidine incorporation in Ro31-8425-, genistein-, and quinacrine-treated cells. A cyclooxygenase inhibitor, indomethacin, which suppressed HGF-induced DNA synthesis, had minimal effect on MAP kinase activation. In contrast, prostaglandin (PG) E1, E2, or F2 alpha, which stimulate [3H]thymidine incorporation to the same level as that caused by HGF in hepatocytes, caused very weak activation of MAP kinases. These results suggest that PTK, Ras, and PKC play roles in MAP kinase activation induced by HGF and that MAP kinase activation resulting in AA release is involved in DNA synthesis in rat hepatocytes.

Animals↗

PubMed1996

Phospholipase D activation in hepatocyte growth factor-stimulated rat hepatocytes mediates the expressions of c-jun and c-fos: involvement of protein tyrosine kinase, protein kinase C, and Ca2+.

Hepatocyte growth factor (HGF) activated phospholipase D (PLD) in primary-cultured rat hepatocytes, as assessed by the formation of phosphatidylbutanol (PBut), a specific and stable product of PLD activity in the presence of 0.3% butanol. PLD hydrolyzes phosphatidylcholine to choline and phosphatidic acid (PA), which is further metabolized to diacylglycerol (DG) by PA phosphohydrolase (PAP). In HGF-stimulated hepatocytes, butanol prevented the formation of PA and DG. A PAP inhibitor, propranolol, inhibited DG production with a reciprocal increase of PA, implying that PLD played a role in the formation of not only PA but DG. Inhibitors for protein kinase C (PKC), Ro31-8425, H-7, and calphostin C, reduced HGF-induced PLD activation. A protein tyrosine kinase (PTK) inhibitor, genistein but not its inactive analogue daidzein, inhibited PLD activation by HGF. Moreover, depletion of extracellular Ca2+ by omission of Ca2+ or by chelating residual Ca2+ with ethyleneglycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid (EGTA) abolished HGF-induced PLD activation. HGF, phorbol myristate acetate (PMA) and a DG analog, oleylacetylglycerol (OAG), activated the expression of c-jun and c-fos messenger RNAs (mRNAs). Ro31-8425, calphostin C, and genistein, which prevented HGF-induced PLD activation, inhibited induction of these immediate early genes. Butanol and propranolol at concentrations which effectively inhibited the formation of DG, suppressed HGF-induced expression of c-jun and c-fos mRNAs. However, HGF-induced mitogen-activated protein kinase (MAPK) activation was not affected by both butanol and propranolol. These results suggest that PTK, PKC, and Ca2+ regulate HGF-induced PLD activation, and that DG produced by PLD pathway may play a role in the induction of immediate early genes, which is activated in MAPK-independent manner, in rat hepatocytes.

Animals↗

PubMed1996

Prevention of coprophagy modifies magnesium absorption in rats fed with fructo-oligosaccharides.

We developed a new type of anal cup for prevention of coprophagy and determined whether the absorption of Ca and Mg and the stimulatory effects of feeding fructo-oligosaccharides (FO) on the absorption of Ca and Mg were altered by prevention of coprophagy in rats. Rats were fed on a FO-free diet or a diet containing 50 g FO/kg for 2 weeks with or without prevention of coprophagy. FO-feeding increased the apparent absorptive ratio of Ca and Mg in rats with or without prevention of coprophagy. However, in the FO-fed groups the absorptive ratio of Mg in rats with prevention of coprophagy was higher than in rats without prevention of coprophagy. The Ca content of the femur was higher in rats fed on the FO-diet than in rats fed on the FO-free diet both with and without coprophagy. In conclusion, FO-feeding increased the absorption of Ca and Mg in rats both with and without coprophagy. Moreover, prevention of coprophagy enhanced the absorption of Mg in rats fed with FO. Coprophagy has to be considered when the effects of luminal fermentation or mineral absorption are examined in rats.

Animals↗

PubMed1996

Sevoflurane, enflurane and isoflurane have no persistent postanaesthetic effects on the central nervous system in cats.

Several reports have appeared on postanaesthetic convulsive disorders in humans after enflurane and isoflurane anaesthesia. However, it is controversial if enflurane induces epileptiform electroencephalogram (EEG), abnormal behaviour, or both, lasting for several days after anaesthesia in laboratory animals. We chronically implanted electrodes for EEG recording in the cortex, medial amygdala and dorsal hippocampus, and for reticular multi-unit activity (R-MUA) in the midbrain reticular formation in five cats. Two weeks later they were anaesthetized with 5.0% sevoflurane, 3.5% enflurane or 4.8% isoflurane for 3-4 h. EEG recordings, R-MUA and behaviour were observed for 1-3 h, during both wakefulness and sleep, every day for 5-7 days after anaesthesia. None of the cats showed abnormal behaviour, or EEG or R-MUA abnormalities after any of the anaesthetics, not only during wakefulness but during slow-wave and paradoxical phases of sleep. These results suggest that if seizures occur after anaesthesia, volatile anaesthesia itself may not be the cause.

Amygdala↗

PubMed1996

An arginine-213 to glycine mutation in human extracellular-superoxide dismutase reduces susceptibility to trypsin-like proteinases.

Molecular genetic studies of extracellular-superoxide dismutase (EC-SOD) have shown that individuals with high serum EC-SOD content have a single base substitution generating the exchange of glycine for arginine-213 (R213G) in the heparin-binding domain of this enzyme [Sandström, J. et al. (1994) J. Biol. Chem. 269, 19163-19166], which causes the impairment of its binding ability to endothelial cell surface [Adachi, T. et al. (1996) Biochem. J. 313, 235-239]. Serum EC-SOD in healthy individuals without the above mutation is heterogeneous with regard to heparin affinity and consists of five fractions, forms (I) to (V), of which (IV) and (V) are the main fractions with high affinity for heparin [Adachi, T. et al. (1995) J. Biochem. 117, 586-590], whereas the major fraction in hemodialysis patients was serum EC-SOD form (I), which is thought to be the proteolytic truncated form. On the other hand, serum EC-SOD in both healthy individuals and hemodialysis patients with the R213G mutation consisted mainly of the high heparin-affinity type. This observation suggests that the susceptibility of EC-SOD to proteinases is reduced by the R213G mutation. The affinity of normal EC-SOD (n-EC-SOD) for heparin decreased by the treatment with trypsin, accompanied by a reduction in the molecular mass. The IC50 of trypsin for the heparin affinity of R213G mutant EC-SOD (m-EC-SOD) was 0.15 microgram/ml, fivefold that for n-EC-SOD. Heparin affinity of n-EC-SOD was again more susceptible to neutrophils than that of m-EC-SOD. These results suggested that m-EC-SOD is more resistant to trypsin and neutrophil-release trypsin-like proteinases than n-EC-SOD, which causes the heparin affinity of serum EC-SOD to differ in individuals with and without the R213G mutation.

Animals↗

PubMed1996

Effects of insulin-like growth factor-I on follicle growth, oocyte maturation, and ovarian steroidogenesis and plasminogen activator activity in the rabbit.

We examined the effects of insulin-like growth factor (IGF)-I on follicular growth, oocyte maturation, and ovarian steroidogenesis and plasminogen activator (PA) activity in vitro, using a perfused rabbit ovary preparation in order to determine whether the follicle-stimulating effects of growth hormone (GH) are mediated by IGF-I. The addition of IGF-I to the perfusate stimulated follicular growth and the resumption of meiosis in follicular oocytes in a dose-dependent manner. There was no significant difference in the production of progesterone by perfused rabbit ovaries between IGF-I-treated and control ovaries, whereas IGF-I increased the production of estradiol (E2) by perfused rabbit ovaries in a dose-dependent manner. The concomitant addition of a monoclonal antibody recognizing the type I IGF receptor, alpha IR-3, to the perfusate significantly blocked IGF-I-stimulated follicular growth, oocyte maturation, and E2 production. Intrafollicular PA activity increased significantly 4 h after exposure to 10 or 100 ng/ml of IGF-I and reached maximal levels at 6 h. The percentage increase in follicle diameter at 6 h after exposure to IGF-I was significantly correlated with the intrafollicular PA activity. Treatment with GH resulted in a 2.7-fold increase in intrafollicular levels of IGF-I mRNA. The binding of [125I]-IGF-I to rabbit ovarian membrane preparations was inhibited by unlabeled IGF-I and IGF-II in a concentration-dependent manner. The relative affinity of the IGF-I receptor for IGF-I, IGF-II, and insulin was typical of type I binding (IGF-I > IGF-II > insulin). Affinity cross-linking of ovarian membranes with [125I]-IGF-I revealed a radiolabeled band corresponding to a molecular weight of 135,000, the alpha subunit of the type I IGF receptor. This band was totally displaced by IGF-I and alpha IR-3. It was concluded that IGF-I stimulated follicular development, E2 production, and oocyte maturation by interacting with its specific receptor located in rabbit ovarian membranes.

Animals↗

PubMed1996

Halothane and diazepam inhibit ketamine-induced c-fos expression in the rat cingulate cortex.

BACKGROUND: Ketamine, a noncompetitive N-methyl-D-aspartate antagonist, has psychotomimetic side effects. Recent studies have shown that noncompetitive N-methyl-D-aspartate antagonists cause morphologic damage to the cingulate and retrosplenial cortices and induce c-fos protein (c-Fos) in the same regions. Although benzodiazepines are effective in preventing these side effects, the neural basis of the drug interactions has not been established. METHODS: The effects of diazepam and halothane on c-Fos expression induced by ketamine were studied. Diazepam (1 and 5 mg/kg) or vehicle were administered subcutaneously, followed 7 min later by 100 mg/kg ketamine given intraperitoneally. Halothane (1.0 and 1.8%), was administered continuously from 10 min before ketamine administration until brain fixation. Two hours after ketamine injection, rats were perfused and their brains fixed and extracted. Brain sections were prepared in a cryostat and c-Fos expression was detected using immunohistochemical methods. RESULTS: Ketamine induced c-Fos-like immunoreactivity in the cingulate and retrosplenial cortices, thalamus, and neocortex. Diazepam suppressed the ketamine-induced c-Fos-like immunoreactivity in the cingulate and retrosplenial cortices in a dose-dependent manner, leaving the thalamus and neocortex less affected. Halothane suppressed the ketamine-induced c-Fos-like immunoreactivity in the cingulate and retrosplenial cortices and the neocortex in a dose-dependent manner, leaving the thalamus relatively unaffected. CONCLUSION: Halothane and diazepam inhibited ketamine-induced c-Fos expression in the cingulate and retrosplenial cortices, leaving the thalamus relatively unaffected.

Anesthetics, Inhalation↗

PubMed1996

[Two cases of Listeria monocytogenes infection in Osaka Municipal Hospital].

We report two cases of sepsis and meningoencephalitis with listeriosis. They died in despite of administering sensitive antibiotics. A 2 day old girl was admitted to our hospital because of fever and cyanosis. Listeria monocytogenes type 4b was cultured from blood, CSF, throat, urine, ear. She was treated with twice exchange transfusion and sensitive antibiotics (ABPC, TOB), but died from DIC. A 48 year old man suddenly experienced an unconscious condition. A CSF culture grew L. monocytogenes type 1/2a. He was treated with sensitive antibiotics (ABPC, CEZ etc), but went bad conditions. Listeria infection of this cases developed as unfortunate infection.

Female↗

PubMed1996

Physiological role of insulin-like-growth-factor-binding protein-4 in human folliculogenesis.

Insulin-like growth factor (IGF)-I and IGF-II, and their binding proteins (IGFBPs) have been demonstrated to play important roles in follicular development as intraovarian regulators. Previous studies have demonstrated that the follicular fluid of atretic follicles contains high levels of IGFBP-2 and IGFBP-4, which are known to inhibit the action of IGFs. In this study, we identified IGFBP-4 protease activity in the follicular fluid of developing but not atretic follicles. To elucidate the regulation mechanism of IGFBP-4 proteolytic activity in the ovary, cultured luteinized granulosa cells (GCs) were incubated with various hormones, and proteolyzed IGFBP-4 in the medium was analyzed. IGFBP-4 proteolytic activity was increased when GCs were incubated with IGFs, estradiol or follicle-stimulating hormone (FSH) but not with testosterone. We also showed that IGFBP-4 inhibited IGF-1-induced estradiol release by GCs while proteolyzed IGFBP-4 did not. These results suggest that human luteinized GCs produce IGFBP-4 protease, and that FSH and IGFs may stimulate folliculogenesis by modulating IGFBP-4 degradation in the ovary.

Cells, Cultured↗

PubMed1996

Serum and tissue levels of manganese superoxide dismutase in testicular germ cell tumors.

OBJECTIVE: To investigate the potential of manganese superoxide dismutase (MnSOD) as a tumor marker for seminoma. MATERIALS: A total of 44 patients with testicular germ cell tumors were assessed for serum and tissue levels of MnSOD in comparison with levels of placental alkaline phosphatase (PLAP). RESULTS: Positive rates of serum MnSOD were 11% for stage I, 25% for stage II and 80% for stage III. No difference was observed in serum MnSOD between seminoma and NSGCT. No difference was demonstrated in tissue MnSOD level between seminoma and NSGCT, or between tumors and their normal counterparts. CONCLUSION: Since serum MnSOD was shown to have lower sensitivity than PLAP, and MnSOD concentration did not differ significantly between tumors and their normal counterparts, the role of MnSOD as a marker for seminoma appears to be limited.

Alkaline Phosphatase↗

PubMed1996

Factors that affect calorie-sensitive and calorie-insensitive reduction in blood pressure during short-term calorie restriction in overweight hypertensive women.

This study was performed to elucidate the factors that affect the reduction in blood pressure produced by calorie restriction in overweight women with essential hypertension. Fifty-one subjects were admitted to the metabolic ward of the hospital. After being fed a standard diet (6.3 to 8.4 MJ/d) for 2 weeks, the calorie-restricted group (n=34) was fed a low-calorie diet (1.9 MJ/d) for an additional 2 weeks. The calorie-nonrestricted group (n=17) was fed the standard diet for 4 weeks. Sodium and potassium intake was kept constant, as was the level of exercise activity. The calorie-restricted group was subdivided into "calorie-sensitive" and "calorie-insensitive" groups based on an average 5 mm Hg reduction in mean blood pressure during the low-calorie diet. The mean age was 51+/-6 years (mean+/-SD) in the calorie-sensitive group (n=16), which was significantly lower than the mean age of 61+/-6 years in the calorie-insensitive group (n=18). Multiple regression analysis indicated that age and change in body weight exhibited significant correlations with blood pressure reduction produced by calorie restriction among 17 parameters. Findings suggest that age can predict the extent of blood pressure reduction that would be obtained during 2 weeks of calorie restriction in overweight hypertensive women. The reduction in blood pressure may be related in part to the amount of weight loss.

Adult↗

PubMed1996

Role of interleukin-4 and vascular cell adhesion molecule-1 in selective eosinophil migration into the airways in allergic asthma.

Recent in vitro studies have suggested that interleukin-4 (IL-4) may be involved in the preferential migration of eosinophils into the airways in allergic asthma through its capacity to selectively increase vascular cell adhesion molecule-1 (VCAM-1) expression on vessels. To test this hypothesis, we studied the expression of VCAM-1, E-selectin, and intercellular adhesion molecule-1 (ICAM-1) on vascular endothelium in bronchial mucosal biopsies from 20 allergic asthmatics using an immunohistochemistry technique and related the observations to IL-4 levels in bronchoalveolar lavage (BAL) fluid simultaneously obtained and to eosinophil infiltration in the bronchial mucosa. IL-4 was detectable in BAL fluid from nine subjects (range, 15.1 to 110 pg/ml in 20-fold concentrated BAL fluid) (IL-4-positive asthmatics) but unmeasurable in the remaining 11 subjects (IL-4-negative asthmatics). The IL-4-positive asthmatics showed a significantly increased expression of VCAM-1 but not E-selectin and ICAM-1 on vessels as compared with both IL-4-negative asthmatics (P < 0.001) and diseased control subjects (P < 0.001). In asthmatics, VCAM-1 expression was positively correlated with BAL IL-4 levels (rs = 0.89; P < 0.0001). Moreover, there was a significant correlation between the endothelial expression of VCAM-1 and the number of eosinophils, but not neutrophils, in the bronchial submucosa (r2 = 0.76; P < 0.001). A significant correlation was also found between BAL IL-4 levels and the number of eosinophils. These results suggest that IL-4 is a VCAM-1-selective activator also in human airways and the VCAM-1-dependent pathways play a role in selective migration of eosinophils into the airways in allergic asthma, and support the hypothesis described above.

Adult↗

PubMed1996

Variable glyceryl dinitrate formation as a function of glutathione S-transferase.

Nitroglycerin (GTN) has been used as the drug of choice in the treatment of angina pectoris. It has been shown that some glutathione S-transferases (GSTs) catalyze the metabolic conversion from GTN to glyceryl dinitrates (GDNs). In this study, we examined the substrate specificity of GSTs for GTN. Alpha and mu GSTs were isolated from porcine liver and intestinal mucosa by means of CM-cellulose and glutathione-affinity column chromatography. Mu GSTs degraded GTN time-dependently and formed 1,3-GDN in preference to 1,2-GDN as a ratio (1,2-GDN/ 1,3-GDN) of 0.61, whereas alpha GSTs formed twice as much 1,2-GDN as 1,3-GDN. These results showed that two GST families participate in the metabolic conversion of GTN at different hydrolyzing portions of the nitrogroups.

Amino Acid Sequence↗

PubMed1996

A comparative study of (Ca(2+)-Mg2+)-ATPase on the lysosomal membrane and ecto-ATPase on the plasma membrane from rat liver.

We showed that rat liver lysosomes possess at least two types of ATPase besides H(+)-translocating ATPase (H(+)-ATPase); namely, N-ethylmaleimide (NEM)-sensitive and bafilomycin A1-insensitive Mg(2+)-ATPase [ATPase I] and NEM- and bafilomycin A1-insensitive (Ca(2+)-Mg2+)-ATPase [ATPase II] [Hayashi H., et al. Chem. Pharm. Bull., 37, 2783-2786 (1992)]. Subcellular fractionation showed the presence of similar activity of (Ca(2+)-Mg2+)-ATPase not only in the Golgi but also in the plasma membrane fractions, of which plasma membrane had the highest activity, most probably due to the ecto-ATPase. In this study, we partially purified the (Ca(2+)-Mg2+)-ATPases from both lysosomal and plasma membranes and compared their properties. Both enzymes had quite similar characteristics including: (1) broad pH-activity profiles with two pH optima at 4.5 and 7.0, (2) K(m) values for ATP being 21-27 microM (at pH 4.5) and 18-14 microM (at pH 7.0) (in the presence of CaCl2), (3) hydrolysis of both nucleoside triphosphates and diphosphate (ADP), (4) inhibition only by vanadate and 4,4'-diisothiocyanatostilbene 2,2'-disulfonic acid (DIDS) at pH 4.0 (but not at pH 7.0), (5) acidic pI values that were shifted by neuraminidase digestion, and (6) a positive reaction against an antibody to the N-terminal peptide of ecto-ATPase.

Adenosine Triphosphatases↗

PubMed1996

Inhibition of purified human sucrase and isomaltase by ethanolamine derivatives.

Sucrase-isomaltase complex was purified from human intestinal mucosa. Immunostaining shows that sucrase-isomaltase is confined to the area of the striated cell borders of human small intestinal absorptive cells of the villus. Inhibition of sucrase and isomaltase activity by ethanolamine derivatives was investigated. Tris inhibits both types of enzyme activity and is the strongest inhibitor of the ethanolamine derivatives investigated. Bis-Tris inhibited sucrase more than isomaltase. On the other hand, mono-, di- and tri-ethanolamine were weak inhibitors of sucrase but not isomaltase.

Electrophoresis, Polyacrylamide Gel↗

PubMed1996

Immunochemical and biochemical identification of the rice seed protein encoded by cDNA clone A3-12.

Previously isolated cDNA clone A3-12 that was expressed in E. coli as the fusion protein with Trp E showed immunoreactivity with the mouse antibody raised against isolated alpha-globulin from rice seed. The N-terminal amino acid sequences determined for the purified alpha-globulin and its tryptic peptides were identical with the deduced amino acid sequence reported, except for two residues at the protein N terminus. An error in the reported sequence was confirmed by re-sequencing the cDNA, the nucleotide sequence for the two N-terminal residues being shown to be CAGCTG and not CACGTG. Thus, the protein encoded by cDNA clone A3-12 was identified to be the major rice seed globulin, alpha-globulin, with an apparent molecular mass of 26kDa.

Alpha-Globulins↗

PubMed1996

Characterization of the bovine kappa-casein gene promoter.

kappa-Casein gene promoter was localized within a 570-bp fragment (-552/+18) of a 5'-flanking region by the gene transfection assay. Deletion mutation analysis in mammary epithelial cell line, HC11, suggested that there are regulatory element in a region from -439 through -125. Some nuclear proteins from lactating rate mammary gland bind to this region specifically. One of them expressed preferentially during pregnancy bound to a 132-bp fragment (-439/-308) and another expressed preferentially during lactation bound to a 183-bp fragment (-307/-125).

Animals↗

PubMed1996

The integrative transformation of Pleurotus ostreatus using bialaphos resistance as a dominant selectable marker.

A plasmid pLC-bar containing the bialaphos resistance gene derived from Streptomyces hygroscopicus between the Lentinus edodes ras gene promoter and priA gene terminator was constructed. When protoplasts of Pleurotus ostreatus were mixed with the plasmid DNA in the presence of polyethylene glycol and CaCl2, bialaphos-resistant colonies were obtained. This indicated that transformation was successful. Southern blot analysis of total DNAs from transformants showed that the introduced plasmid DNA was integrated into the host chromosome and partly rearranged. A plasmid, pLC-GUS, containing the Escherichia coli beta-glucuronidase (GUS) gene under the control of the L. edodes ras gene promoter and priA gene terminator was constructed and introduced into protoplasts of P. ostreatus with pLC-bar by co-transformation. Two of 5 transformants obtained as bialaphos-resistant colonies showed two to twenty times higher specific activity of GUS than the recipient. Southern blot analysis of total DNAs from transformants indicated the presence of the GUS gene only in the two transformants. These results indicated that co-transformation of P. ostreatus was successful, and that the GUS gene was expressed in P. ostreatus. This transformation system will enable us to breed commercial strains of P. ostreatus at the molecular level.

DNA, Fungal↗