Microvascular permeability change induced by platelet-activating factor is impaired in diabetic mice.
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
K Wada
Publications and source records attributed to K Wada.
Protein kinase C mediates tumor necrosis factor-alpha-induced inhibition of obese gene expression and leptin secretion in brown adipocytes.
Previously we showed that tumor necrosis factor-alpha (TNF-alpha) inhibits lipoprotein lipase (LPL) activity and its gene expression, an early marker of adipocyte differentiation, in cultured brown adipocytes. To know whether TNF-alpha also affects late events in brown adipocyte maturation, we examined the effect of TNF-alpha on obese gene expression and leptin secretion in mouse brown adipocytes differentiated in culture. TNF-alpha caused a concentration-dependent decrease in leptin accumulation in culture medium and leptin mRNA amount in brown adipocytes which constitutively express the ob gene. Time-course study showed that TNF-alpha significantly suppressed leptin secretion during incubation for 16, 24 and 48 h. Since some effect of TNF-alpha is mediated by activation of protein kinase C (PKC), the role of PKC in TNF-alpha-induced downregulation of ob gene expression and leptin secretion was studied. The suppressive effect of TNF-alpha on both ob gene expression and leptin secretion was blocked by PKC inhibitors such as bisindolylmaleimide I (BIM) and 1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride (H-7). Incubation of brown adipocytes with TNF-alpha (20 ng/ml, 15 min) caused a rapid shift of PKC activity from the cytosolic to the membrane fraction, suggesting an activation of PKC by TNF-alpha in brown adipocytes. This effect of TNF-alpha was blocked by a selective PKC inhibitor, BIM. These results suggest that TNF-alpha promotes dedifferentiation of the brown adipocytes as evidenced by a downregulation in ob gene expression and leptin secretion via PKC-dependent mechanisms.
1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
Expression of transforming growth factor (TGF)-alpha, TGF-beta(2) and interleukin 8 messenger RNA in postsurgical and cultured lens epithelial cells obtained from patients with senile cataracts.
BACKGROUND: Testing our hypothesis that residual lens epithelial cells (LEC) participate in the pseudophakic inflammation by producing cytokines, prostaglandins (PG) or both, we detected interleukin-1 (IL-1), IL-6, b-FGF and PGE(2) in the incubation medium of cultured LEC. This paper describes our subsequent work on the expression of TGF-alpha, TGF-beta(2), IL-4 and IL-8 mRNA in postsurgical and cultured LEC. METHODS: The anterior lens capsule with attached LEC was obtained by anterior capsulotomy during cataract surgery and cultured. Specimens in serum-free medium immediately after surgery or those in serum-added medium after 2 weeks of culture were used. Reverse transcriptase-polymerase chain reaction (PCR) and electrophoresis were used to detect mRNA coding for TGF-alpha, TGF-beta(2), IL-4 and IL-8 in human cataract LEC. RESULTS: Electrophoresis of the PCR products showed that appropriately sized amplification products were specific for TGF-alpha and TGF-beta(2) in the specimens immediately after surgery and after culturing, and IL-8 in the cultured LEC. IL-4 was not detected in either group of specimens. CONCLUSIONS: Human cataract LEC synthesize TGF-alpha and TGF-beta(2) mRNA in situ and after culturing, and the cultured LEC also synthesize IL-8 mRNA. These cytokines may be synthesized by LEC in vitro and play an important role in an autocrine or paracrine manner in the proliferative process of LEC after cataract surgery, which can cause inflammation and aftercataract.
Aged↗
AVP-induced mitogenic responses of Chinese hamster ovary cells expressing human V1A or V1B receptors.
Arginine vasopressin (AVP) induces cell proliferation and hypertrophy; however, the human receptor subtype and the intracellular signaling pathways responsible for this mitogenic activity remain unclear. Experiments were conducted to determine which AVP receptor is linked to mitogen-activated protein (MAP) kinase activation and the mitogenic effect seen in Chinese hamster ovary (CHO) cells expressing human V1A or V1B receptors. Adding AVP to CHO cells transfected with human V1A or V1B cDNA significantly and concentration-dependently induced activation of MAP kinase and increased DNA synthesis, as measured by [3H]thymidine incorporation. These effects were inhibited by AVP receptor antagonists and the potency order of antagonists in vitro was similar to that observed in radioligand binding assays. These results suggest that AVP induces the MAP kinase cascade leading to cell proliferation through either human V1A or V1B receptors, and that these cloned, expressed AVP receptors may prove an invaluable tool for probing the physiologic and pathophysiologic effects of AVP.
Animals↗
Antibacterial action of bile acids against Helicobacter pylori and changes in its ultrastructural morphology: effect of unconjugated dihydroxy bile acid.
Although it has been shown that bile acids possess antibacterial activity against Helicobacter pylori, few reports on their activity have been published. We determined the minimum inhibitory concentration at 72 h of various unconjugated and conjugated bile acids against laboratory standard strains and clinical isolates of H. pylori, and studied morphologic changes of H. pylori under the scanning electron microscope during treatment with deoxycholic acid and ursodeoxycholic acid at the minimum inhibitory concentrations for 24 h. We found that only the unconjugated form of dihydroxy bile acid has antibacterial activity. The minimum inhibitory concentration of deoxycholic acid is 200-400 microg/ml, that of chenodeoxycholic acid is similar to that of deoxycholic acid, and that of ursodeoxycholic acid is 400-800 microg/ml. The morphology of H. pylori changed from its primary rodlike shape to a spherical shape with blebs on the cell surface, and was further degraded to an irregularly condensed mass, following an increase in bile acid. This morphologic change in H. pylori was different from the change to a spherical shape caused by amoxicillin. On the basis of these results, it seems that unconjugated dihydroxy bile acid might be a candidate drug for eradication of H. pylori, but further investigations of the clinical usefulness of bile acid for this purpose should be done.
Bile Acids and Salts↗
New adipogenic cell lines derived from C3H10T1/2.
Explore the source record for details and available documents.
Adipocytes↗
Expression of heregulin alpha, erbB2, and erbB3 and their influences on proliferation of gastric epithelial cells.
BACKGROUND & AIMS: Heregulins (HRGs) regulate the proliferation and differentiation of various cell types. However, very little is known about their function in the gastrointestinal tract. The aim of this study was to investigate the role of HRGs on gastrointestinal cells. METHODS: We examined the expression of erbB receptors and HRG-alpha in human gastric cancer cell lines, rat gastrointestinal epithelial cells, and human gastric fibroblasts by Western blot analysis or reverse-transcription polymerase chain reaction. Receptor phosphorylation and heterodimerization induced by HRG-alpha were detected by Western blot analysis. We also evaluated the in vitro effects of HRG-alpha on cell proliferation and restitution. RESULTS: Cancer cell lines and rat epithelial cells expressed erbB2 and erbB3, but protein expression of erbB4 was not detected. HRG-alpha was detected only in gastric fibroblasts. HRG-alpha activated tyrosine phosphorylation of epidermal growth factor receptor (EGFR), erbB2, and erbB3 and induced not only erbB3/erbB2 but also erbB3/EGFR and erbB2/EGFR heterodimer formation in MKN-28 cancer cells. Simultaneous cultivation of MKN-28 cells with gastric fibroblasts resulted in tyrosine phosphorylation of erbB3 in MKN-28 cells. HRG-alpha also stimulated proliferation of MKN-28 cells and gastric epithelial cells. CONCLUSIONS: The data suggest that HRG-alpha may affect epithelial cell proliferation through mesenchymal-epithelial interaction in the gastric mucosa.
Animals↗
Effect of suplatast tosilate (IPD-1151T) on cytokine production by allergen-specific human Th1 and Th2 cell lines.
Suplatast tosilate (IPD-1151T) is an antiallergic agent that suppresses airway eosinophil infiltration in asthma. We investigated the effects of IPD-1151T on proliferative response and cytokine production by human antigen-specific T cell lines. Purified protein derivatives (PPD)-specific T helper 1 (Th1) cell lines and Dermatophagoides farinae (Der f)-specific T helper 2 (Th2) cell lines were established from patients with asthma sensitized with house dust mite. Stimulation of PPD-specific and Der f-specific T cell lines with relevant antigens resulted in production of mostly interferon (IFN)-gamma and of interleukin (IL)-4 and IL-5, respectively. IPD-1151T did not inhibit the proliferative responses of either the Th1 or Th2 cell line to antigens. Although IPD-1151T did not inhibit IFN-gamma production by PPD-specific Th1 cell lines, it did inhibit IL-4 and IL-5 production by antigen-stimulated Der f-specific Th2 cell lines in a dose-dependent manner. IPD-1151T directly inhibited cytokine production by Der f-specific Th2 cell lines stimulated with immobilized anti-CD3 antibodies. Although IPD-1151T did not inhibit the clonal expansion of memory T cells among PBMCs into PPD-specific Th1 and Th2 cell lines, it did inhibit IL-4 and IL-5 production by Der f-specific Th2 cell lines but not IFN-gamma production by PPD-specific Th1 cell lines. These results suggest that IPD-1151T selectively inhibits Th2-type cytokine production.
Allergens↗
Interaction between purinoceptor subtypes on hippocampal serotonergic transmission using in vivo microdialysis.
The effects of purinoceptor subtypes on hippocampal extracellular serotonin levels were determined by using in vivo microdialysis. Perfusion with adenosine-5'-triphosphate (ATP) for 20 min produced concentration-dependent changes in hippocampal extracellular serotonin levels, which consisted of an initial rise phase, with levels increasing to 309% of control with 100 microM ATP, followed by a later rebound reduction phase, with levels decreasing to 6% of control. The P2X1-7 active P2 purinoceptor agonist, 2-methylthioATP (2-MeSATP: 100 microM) increased the extracellular serotonin level drastically (638%), while the P2X1,3 active P2 purinoceptor agonist, alpha, beta-methylene-L-ATP (alpha, beta-meATP: 100 microM) produced a small increase (132%) in the serotonin level. The P2X1,2,3,5,7 active P2 purinoceptor antagonist, suramin (100 microM), reduced the basal serotonin level (86%) and the ATP-evoked initial rise phase (from 309 to 254%) without affecting the late reduction phase. The adenosine A1 receptor antagonist, 8-cyclopentyl-1,3-dimethylxanthine (CPT: 50 microM) potentiated the rising phase (167%) and abolished the subsequent ATP-evoked reduction phase. Perfusion with CPT and an adenosine A2 receptor antagonist, 3,7-dimethyl-1-propargylxanthine (DMPX: 10 microM), reduced the ATP-evoked initial rise (to 181%) and abolished the late reduction phases of serotonin release. These results indicate that ATP-evoked hippocampal serotonin release is composed of an initial rise phase and a later reduction phase. The ATP-evoked initial rise phase might be produced by an activation of P2X purinoceptor function, whereas the late reduction phase was modulated by the activation of adenosine A1 receptor function by adenosine, metabolized from ATP in the synaptic cleft.
Adenosine Triphosphate↗
Hyperresponsiveness to palatable and aversive taste stimuli in genetically obese (bombesin receptor subtype-3-deficient) mice.
Taste preference in obese mice was examined using genetically obese (bombesin receptor subtype-3: BRS-3 deficient) animals. Preference for either sodium saccharin (0.2%). sodium chloride (0.9%), citric acid (0.1%), or quinine sulfate (0.002%) solution was examined using a two-bottle test situation, and BRS-3 deficient mice not only showed a stronger preference for saccharin solution, but also a stronger aversive response to quinine solution, relative to wild-type littermates. Furthermore, a conditioned taste-aversion test measured the consumption of sodium saccharin (0.2%) and sodium chloride (0.9%) solutions after intraperitoneal injection of LiCl (0.3 M, 1 mg/kg), and BRS-3-deficient mice exhibited stronger aversion to both solutions than did control animals. In situ hybridization demonstrated that the BRS-3 gene is expressed in the parabrachial nucleus, the medial and central nuclei of the amygdala, and the hypothalamic nuclei such as paraventricular nucleus, all of which are known to be involved in taste perception. These results suggest that expression of the BRS-3 gene in these nuclei is important for the modulation of taste preference, as well as the development of obesity.
Analysis of Variance↗
Identification of break points in mutated PMP22 gene in a new Trembler (Tr-Ncnp) mouse.
Explore the source record for details and available documents.
Animals↗
Effects of bilobalide, a sesquiterpene in Ginkgo biloba leaves, on population spikes in rat hippocampal slices.
The effects of bilobalide, a sesquiterpene isolated from the leaves of Ginkgo biloba L., were investigated in a rat hippocampal slice preparation. Bilobalide (10-500 microM) significantly increased the amplitude of population spikes evoked by electrical stimulation of Schaffer collateral/commissural fibers in a concentration-dependent manner. Paired-pulse inhibition at interpulse intervals of 10-50 ms was significantly reduced in the presence of bilobalide (50 microM). The inhibitory action of muscimol (1 microM) was attenuated by bilobalide (100 microM). These results suggest that bilobalide induces an enhancement of excitability of CA1 pyramidal neurons, which involves, at least in part, a reduction in GABAergic inhibition in rat hippocampus.
Action Potentials↗
Congenital malformations due to antiepileptic drugs.
To identify the major risk factors for the increased incidence of congenital malformations in offspring of mothers being treated for epilepsy with antiepileptic drugs (AEDs) during pregnancy and, to determine the relative teratogenic risk of AEDs, we prospectively analyzed 983 offspring born in Japan, Italy, and Canada. The incidence of congenital malformations in offspring without drug exposure was 3.1%, versus an incidence with drug exposure of 9.0%. The highest incidence in offspring exposed to a single AED occurred with primidone (PRM; 14.3%), which was followed by valproate (VPA; 11.1%), phenytoin (PHT; 9.1%), carbamazepine (CBZ; 5.7%), and phenobarbital (PB; 5.1%). The VPA dose and level positively correlated with the incidence of malformations. This study first determined a cut-off value of VPA dose and level at 1000 mg/day and 70 microg/ml, respectively, to avoid the occurrence of malformations. The incidence of malformations increases as the number of drugs increases, and as the total daily dose increases. Specific combinations of AEDs such as VPA + CBZ and PHT + PRM + PB produced a higher incidence of congenital malformations. The incidence of malformations was not associated with any background factors studied except for the presence of malformations in siblings. These results indicate that the increased incidence of congenital malformations was caused primarily by AEDs, suggesting that malformations can be prevented by improvements in drug regimen, and by avoiding polypharmacy and high levels of VPA (more than 70 microg/ml) in the treatment of epileptic women of childbearimg age.
Abnormalities, Drug-Induced↗
Biphasic effects of zonisamide on serotonergic system in rat hippocampus.
To study the mechanisms of antiepileptic action of zonisamide (ZNS), we determined the effects of ZNS on extracellular, total levels and re-uptake activity of serotonin (5-HT) in rat striatum and hippocampus. After acute administrations, plasma ZNS concentrations associated with anticonvulsive action (effective concentrations) increased the total levels of 5-HT, its metabolise (5-hydroxyindoleacetic acid: 5-HIAA) and precursor (5-hydroxytryptophan: 5-HTP). After chronic administration of ZNS, effective plasma concentrations also increased the extracellular and total levels of 5-HT, 5-HIAA, and 5-HTP. On the other hand, after both acute and chronic administrations of ZNS, a supra-effective ZNS concentration either decreased or did not affect the total levels of these substances. Therefore, the stimulatory effects of ZNS on the 5-HT system were reduced by an increase in ZNS concentration to supra-effective concentrations. ZNS concentrations of 30-1000 microM did not affect hippocampal 5HT re uptake activity in vitro. These results suggest that ZNS has biphasic effects on the 5-HT system, in that effective concentrations of ZNS enhance and supra-effective concentrations of ZNS reduce the function of the 5-HT system. These biphasic effects of ZNS on the 5-HT system may be involved in the mechanisms of action of the antiepileptic and psychotropic effects, and side effects of ZNS.
5-Hydroxytryptophan↗
Effects of zonisamide on K+ and Ca2+ evoked release of monoamine as well as K+ evoked intracellular Ca2+ mobilization in rat hippocampus.
To clarify the effects of zonisamide (ZNS) on neurotransmission and intracellular Ca2+ mobilization, both Ca2+ and K+ evoked hippocampal releases of dopamine (DA) and serotonin (5-HT) were determined by in vivo microdialysis, and K+ (25 and 50 mM) evoked elevation of intracellular Ca2+ level was determined by fluorescence microscopy in vitro. Therapeutic concentrations of ZNS had different effects on Ca2+ and K+ evoked release of monoamine. ZNS stimulated Ca2+ evoked monoamine release, while ZNS inhibited K+ evoked monoamine release. ZNS inhibited K+ evoked elevation of hippocampal intracellular Ca2+ levels in a concentration dependent manner. These results suggest that ZNS inhibits the depolarization induced by neuronal excitation, whereas ZNS might enhance the N-type Ca2+ channel activity or N-type Ca2+ channel related exocytosis mechanisms.
Animals↗
Intragenic deletion in the gene encoding ubiquitin carboxy-terminal hydrolase in gad mice.
The gracile axonal dystrophy (gad) mouse is an autosomal recessive mutant that shows sensory ataxia at an early stage, followed by motor ataxia at a later stage. Pathologically, the mutant is characterized by 'dying-back' type axonal degeneration and formation of spheroid bodies in nerve terminals. Recent pathological observations have associated brain ageing and neurodegenerative diseases with progressive accumulation of ubiquitinated protein conjugates. In gad mice, accumulation of amyloid beta-protein and ubiquitin-positive deposits occur retrogradely along the sensory and motor nervous systems. We previously reported that the gad mutation was transmitted by a gene on chromosome 5 (refs 10,11). Here we find that the gad mutation is caused by an in-frame deletion including exons 7 and 8 of Uchl1, encoding the ubiquitin carboxy-terminal hydrolase (UCH) isozyme (Uch-l1) selectively expressed in the nervous system and testis. The gad allele encodes a truncated Uch-l1 lacking a segment of 42 amino acids containing a catalytic residue. As Uch-l1 is thought to stimulate protein degradation by generating free monomeric ubiquitin, the gad mutation appears to affect protein turnover. Our data suggest that altered function of the ubiquitin system directly causes neurodegeneration. The gad mouse provides a useful model for investigating human neurodegenerative disorders.
Amino Acid Sequence↗
HIV and HCV infection among drug users in Japan.
AIMS: To assess seroprevalence of human immunodeficiency virus (HIV), hepatitis C virus, injecting drug use, unsafe sexual behaviours, self-mutilation and tattoos in patients attending a drug and alcohol treatment centre in Japan. DESIGN: Cross-sectional survey. SETTING: The work was carried out at the National Sanitarium of Shimousa, Chiba, Japan, a 32-bed inpatient centre specializing in drug and alcohol treatment. MEASUREMENTS: Laboratory analyses for HIV antibody, hepatitis C antibody, hepatitis B antigen and antibody; questionnaires for history of sexual activities, needle and syringe use; physical examination with assessment of self-amputated finger joints, tattoos, scars from lacerations and cigarette burns. FINDINGS: No patients tested positive for anti-HIV. The seroprevalence of anti-HCV positives was 53.8% of methamphetamine-dependent patients, 18.4% of solvent-dependent patients and 5.6% of alcohol-dependent patients. Past needle sharing was reported by 82.1% of methamphetamine-dependent patients, 18.4% of solvent-dependent patients and 5.6% of alcohol-dependent patients. A history of syringe sharing was reported by 87.2% of methamphetamine-dependent patients. More than two-thirds of all patients reported contact with commercial sex workers. Casual sexual contacts were more common among solvent and methamphetamine-dependent patients than those dependent on alcohol. Tattoos and cigarette burns were more common among methamphetamine and solvent-dependent patients than among alcohol-dependent patients. Among the methamphetamine-dependent patients, 20.5% reported self-amputated finger joints compared with none in the other patient groups. CONCLUSIONS: HCV prevalence is a significant problem among methamphetamine users in Japan, probably because of a high rate of needle and/or syringe sharing. Although HIV infection is currently negligible, the very high rate of needle and syringe sharing could give rise to a significant increase in the HIV rate among drug users in the future.
Adult↗
Biological functions of proline in morphogenesis and osmotolerance revealed in antisense transgenic Arabidopsis thaliana.
Many organisms, including higher plants, accumulate free proline (Pro) in response to osmotic stress. Although various studies have focused on the ability of Pro as a compatible osmolyte involved in osmotolerance, its specific role throughout plant growth is still unclear. It has been reported that Pro is synthesized from Glu catalyzed by a key enzyme, delta 1-pyrroline-5-carboxylate synthetase (P5CS), in plants. To elucidate essential roles of Pro, we generated antisense transgenic Arabidopsis plants with a P5CS cDNA. Several transgenics accumulated Pro at a significantly lower level than wild-type plants, providing direct evidence for a key role of P5CS in Pro production in Arabidopsis. These antisense transgenics showed morphological alterations in leaves and a defect in elongation of inflorescences. Furthermore, transgenic leaves were hypersensitive to osmotic stress. Microscopic analysis of transgenic leaves, in which the mutated phenotype clearly occurred, showed morphological abnormalities of epidermal and parenchymatous cells and retardation of differentiation of vascular systems. These phenotypes were suppressed by exogenous L-Pro but not by D-Pro or other Pro analogues. In addition, Pro deficiency did not broadly affect all proteins but specifically affected structural proteins of cell walls in the antisense transgenic plants. These results indicate that Pro is not just an osmoregulator in stressed plants but has a unique function involved in osmotolerance as well as in morphogenesis as a major constituent of cell wall structural proteins in plants.
Adaptation, Physiological↗