Biomedical subjects

T Takeda

Publications and source records attributed to T Takeda.

At least 577 records · Page 32Linked to original sources

PubMed1994

Production and cross-reactivity patterns of a panel of high affinity monoclonal antibodies to Vibrio cholerae O139 Bengal.

A series of monoclonal antibodies of different isotypes specific for Vibrio cholerae O139, the new pandemic strain of cholera, was produced. These mAbs reacted only with the reference strain (MO45) representing serovar O139 but did not react with any of the other reference strains representing serovars O1 to O140. Significantly, the mAbs did not agglutinate the R-cultures of V. cholerae (CA385, 20-93) which demonstrated the exceptional specificity of these mAbs and indicated that the mAbs recognized antigenic determinants unique for the O139 serovar. There was heterogeneity in the intensity of reactivity of the mAbs with strains of V. cholerae O139 isolated from diverse sources. Apart from 4H6, the other mAbs agglutinated all the O139 strains examined. 2D12 and 2F8 were the best mAbs based on the intensity of agglutination with all the O139 strains. Evaluation of 3A10 in comparison with a polyclonal anti-O139 antibody raised in rabbit using the slide agglutination format revealed that 3A10 fared as well as the polyclonal antibody for the laboratory identification of the O139 serovar. The acquisition of these mAbs provide reagents which would be very useful in the development of simple immunodiagnostic assays for the diagnosis of V. cholerae O139 infections.

Agglutination Tests↗

PubMed1994

Accumulation of blood-borne horseradish peroxidase in medial portions of the mouse hippocampus.

The intracerebral distribution of intravenously injected horseradish peroxidase (HRP) in young adult DDD mice was examined. HRP-tetramethylbenzidine reaction products were observed in the medial portions of the hippocampus, particularly the medial CA1 region and medial dentate gyrus. Reaction products were observed in the subfornical organ in mice decapitated 5 min after HRP injection, and then also progressively more caudally in the medial portions of the hippocampus as postinjection survival time increased. These findings suggest that blood-borne macromolecules have ready access to the medial portions of the hippocampus, particularly the medial CA1 region and medial dentate gyrus.

Animals↗

PubMed1994

Direct evidence of neuron impairment by oral infection with verotoxin-producing Escherichia coli O157:H- in mitomycin-treated mice.

We developed a mouse model of acute encephalopathy induced by verotoxin 2 variant (VT2v)-producing Escherichia coli. Three-week-old mice were inoculated intragastrically with approximately 10(10) CFU of E. coli O157:H- strain E32511/HSC and simultaneously given an intraperitoneal injection of mitomycin (MMC; 2.5 mg/kg). Drinking water containing 5 g of streptomycin sulfate per liter was given ad libitum from 3 days before the infection. From 1 to 2 days after bacterial inoculation, clinical features including weight loss, weakness, and flaccid paralysis of the extremities developed, usually culminating in death within 4 days. Diarrhea was not observed during the course of disease. No mice died in the absence of streptomycin or MMC treatment for 2 weeks after the oral bacterial infection. Judging from the clinical course and the biochemical and histological examination, the cause of death was not likely to be attributable to renal failure or to a side effect of MMC. To better understand the cause of death, we examined the brain cortex and spinal cord of the moribund mice by electron microscopy. Mice showing mortal symptoms were given horseradish peroxidase intravenously. The tracer was present in the endothelial basal lamina, in the surrounding extracellular spaces, and even in the neuron fibers of the brain cortex. Furthermore, immunoreactivity of VT2v, proved by the use of rabbit anti-VT2 serum, was localized selectively in the damaged myelin sheaths of neuron fibers which were accompanied by edematous axons in the brain cortex and spinal cord. These findings strongly suggest that VT2v is toxic to both endothelial cells and neurons in the central nervous system and subsequently causes fatal acute encephalopathy.

Acute Disease↗

PubMed1994

Role of endogenous atrial natriuretic peptide on systemic and renal hemodynamics in heart failure rats.

To investigate the role of endogenous atrial natriuretic peptide (ANP) in rats with heart failure (HF), we administered HS-142-1 (HS; 3 mg/kg body wt iv), a novel nonpeptide ANP-receptor antagonist, to rats with surgically induced myocardial infarction and sham-operated rats. HF was characterized by a higher left ventricular end-diastolic pressure and higher plasma ANP concentration vs. controls. HS administration significantly reduced the plasma and urinary levels of guanosine 3',5'-cyclic monophosphate in rats with HF [plasma concentration 10.6 +/- 2.6 vs. 2.7 +/- 0.4 nM (P < 0.05); urinary excretion 48 +/- 8 vs. 12 +/- 2 pmol/min (P < 0.05)]. Systemic and renal hemodynamics were unaffected by HS administration. Urine flow (-35%) and urinary sodium excretion (-50%) were significantly decreased after HS only in those rats with HF that had no changes in systemic and renal hemodynamics. These results suggest that the elevated ANP levels in HF do not contribute directly to the maintenance of systemic hemodynamics but rather compensate for the HF mainly via diuresis and natriuresis, achieved by the inhibition of renal tubular reabsorption rather than by renal vasodilatation.

Animals↗

PubMed1994

Cardiac hypertrophy and brain natriuretic peptide in experimental hypertension.

The blood pressure was decreased after chronic treatment with enalapril, MK-954, and hydralazine in deoxycorticosterone acetate (DOCA)-salt-induced malignant hypertension of spontaneously hypertensive rats (SHR); however, ventricular weight and plasma brain natriuretic peptide (BNP) concentration were decreased after enalapril and MK-954 but not after hydralazine. The BNP secretory rates from the ventricle in enalapril- and MK-954-treated DOCA-salt SHR were decreased to approximately 50% of those in untreated DOCA-salt SHR. The BNP secretory rate from the ventricle was positively correlated with ventricular weight in untreated and treated DOCA-salt SHR. In contrast, acute administration of captopril or MK-954 did not decrease the BNP secretory rate from the heart. Results suggest that the decrease in plasma BNP after enalapril and MK-954 is attributed to a decline in the secretion from the ventricle but not from the atrium. The reduction in ventricular mass appeared to be related to this decline.

Animals↗

PubMed1994

Dopamine DA1 receptors on vascular smooth muscle cells are regulated by glucocorticoid and sodium chloride.

The modulation of dopamine DA1 receptors of cultured rat renal arterial smooth muscle cells by glucocorticoid and sodium chloride was studied. At a concentration of 10 nM, the synthetic glucocorticoid dexamethasone increased maximum receptor binding but had no effect on the dissociation constant. However, the maximum binding of [3H]Sch-23390 in cells treated with 100 mM sodium chloride did not change. However, the dissociation constant for DA1 receptor was increased by adding sodium chloride. The glucocorticoid effect on DA1 of arterial smooth muscle cells became apparent after hours of incubation in the presence of the steroid and was significantly inhibited by cycloheximide (10 micrograms/ml) or by the glucocorticoid receptor antagonist RU-38486, indicating that the effect required protein synthesis through glucocorticoid receptors. Treatment of cells with 1 microM dexamethasone for 24 h increased basal and DA1-stimulated adenylate cyclase activity. Basal adenylate cyclase was decreased by sodium chloride in a dose-dependent manner. These results suggest differential control of DA1 receptors on vascular smooth muscle cells by glucocorticoid or sodium chloride.

Adenylyl Cyclases↗

PubMed1994

Phosphoinositide turnover signaling stimulated by ET-3 in endothelial cells from spontaneously hypertensive rats.

Endothelin (ET) B-type receptor-mediated signal transduction after stimulation with ET-3 was examined in cultured aortic endothelial cells obtained from spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats. The purpose of this study was to elucidate ETB receptor-mediated response in endothelial cells from hypertensive rat models. Non-isopeptide-selective displacement and affinity in these binding experiments suggest that aortic endothelial cell receptors for ET-3 correspond to ETB receptor subtypes. These receptors for ET-3 were similar in WKY and SHR endothelial cells. ETB receptor mRNA expression in cultured endothelial cells was also similar in WKY and SHR. However, the cytosolic free Ca2+ level in the absence of extracellular Ca2+ as well as the inositol 1,4,5-trisphosphate level in response to ET-3 were greater in endothelial cells from SHR than in those from WKY. Phospholipase C and protein kinase C activities after stimulation with ET-3 were also greater in SHR than in WKY. The 6-ketoprostaglandin F1 alpha production was also augmented in SHR, although nitric oxide formation and guanosine 3',5'-cyclic monophosphate production after stimulation with ET-3 were similar in WKY and SHR. We conclude that the phosphoinositide turnover signaling stimulated by ET-3 is augmented in cultured aortic endothelial cells from SHR compared with those from WKY.

Animals↗

PubMed1994

Endothelin modulates the mitogenic effect of PDGF on glomerular mesangial cells.

We showed that two isoforms of platelet-derived growth factor (PDGF), AB and BB, stimulate the secretion of endothelin (ET)-1 from cultured rat mesangial cells. Then, we examined whether PDGF AB and BB stimulate mesangial cell proliferation through the modulation of the endogenous production of ET-1 in these cells. Mitogenesis experiments were assessed by tritiated thymidine incorporation into DNA under highest concentrations (10 ng/ml) of PDGF AB and BB in the presence and absence of anti-ET-1 antiserum or a selective A-type endothelin receptor (ETA receptor) antagonist, BQ-123. PDGF AB and BB potently stimulate thymidine incorporation. This stimulation was significantly attenuated in the presence of either anti-ET-1 antiserum or BQ-123 (10(-7)-10(-5)M). Results suggest that PDGF AB and BB stimulate ET-1 secretion in rat mesangial cells through PDGF beta-receptors, and endogenously produced ET-1 serves to modulate the mitogenic effect of PDGF AB and BB, probably via ETA receptors in these cells.

Animals↗

PubMed1994

Age-related changes in lung structure and function in the senescence-accelerated mouse (SAM): SAM-P/1 as a new murine model of senile hyperinflation of lung.

Age-related changes in lung structure and function were investigated in murine models of accelerated senescence (SAM-P/1) and of normal aging (SAM-R/1). In morphometric studies, most of the parameters examined, including lung volume, mean linear intercept, total alveolar duct air volume, and total alveolar air volume, began to increase and the internal surface area per unit lung volume and total elastic fiber length per unit lung volume began to decrease from 2 months of age, and these changes continued to progress up to 10 months of age in SAM-P/1. In SAM-R/1, there were no significant changes in these parameters from 2 to 6 months of age, thereafter slight but steady changes were observed up to 25 months of age. Thus, significant differences in these parameters between SAM-P/1 and SAM-R/1 became evident in mice 6 to 17 months of age. Internal surface area and total elastic fiber length showed no age-related changes after 2 months of age, and total alveolar air volume showed no age-related changes after 6 months of age in either strain. All morphometric parameters examined showed similar levels at 17 months of age in SAM-P/1 and 25 months of age in SAM-R/1. Histologic observations revealed no evidence of destruction of the alveolar wall or elastic fibers in the lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗

PubMed1994

Differential aging pattern of cerebral accumulation of radiolabeled glucose and amino acid in the senescence accelerated mouse (SAM), a new model for the study of memory impairment.

Using an accelerated senescence-prone model mouse strain, SAMP8, with spontaneously occurring age-related deficits in learning and memory, cerebral glucose and amino acid accumulation were investigated to study the metabolic abnormalities in relation to age. The findings were compared with those in an accelerated senescence-resistant mouse strain, SAMR1, without deterioration of ability in learning and memory. [14C]-2-Deoxyglucose accumulation in the SAMP8 brain was normal at 1 month of age but decreased from 2-3 months of age onwards. In contrast, tyrosine accumulation was unchanged from 1 to 5 months of age. The impairment of memory in the SAMP8 at 2-3 months of age corresponded with the decrease in [14C]-2-deoxyglucose accumulation, but was not related to Tyr. This animal model may help provide new information on the metabolic changes in aging.

Aging↗

PubMed1994

Studies on the constituents of Calliandra anomala (Kunth) Macbr. II. Structure elucidation of four acylated triterpenoidal saponins.

Four new triterpenoidal saponins, called calliandra saponins B (8), C (9), D (10), and F (12), were isolated from the branches of Calliandra anomala (Kunth) Macbr. The structures of these compounds were established on the basis of NMR spectra, FAB-MS, and the chemical evidence. These saponins, interestingly, have a N-acetyl glucosamine at the 3 position of the genin, and one or two monoterpene glycosides at the position of the sugar chain.

Acetylglucosamine↗

PubMed1994

Development and application of an enzyme immunoassay for karasurin A, an effective protein component of Trichosanthes kirilowii Max. var. japonicum Kitam.

A method was developed for specific estimation of the content of a non-enzymatic protein, karasurin A, in fractions taken during the extraction and purification processes from a natural source. Anti-karokon serum was elicited in rabbits immunized with fragments of karokon, a dried root tuber of Trichosanthes kirilowii Max. var. japonicum Kitam. Rabbit antibody specific for karasurin A was identified in anti-karokon serum by the Western blotting method. After separation by SDS-PAGE, protein bands of purified karasurin A and extracted proteins from a medicinal herb which is a karasurin A source were reacted with anti-karokon serum followed by treatment with horseradish peroxidase (HRP)-labeled Fab' of goat anti-rabbit IgG, and then bound HRP-labeled second antibody on protein bands was developed to brown by reaction with a substrate solution of the used enzyme. A novel selected antibody enzyme immunoassay (SAEIA) for karasurin A was developed using selective binding of anti-karasurin A antibody in anti-karokon serum to solid phase karasurin A and HRP-labeled Fab' of the second antibody as the tracer. Specific estimation of the content of karasurin A in several fractions taken during the isolation and purification processes of the protein were possible using the SAEIA method.

Animals↗

PubMed1994

Bryonolic acid production in hairy roots of Trichosanthes kirilowii Max. var Japonica Kitam. Transformed with Agrobacterium rhizogenes and its cytotoxic activity.

The hairy roots of Trichosanthes kirilowii Max, var. japonica Kitam. were induced by Agrobacterium rhizogenes (TCC 15834) on sterile shoots. The axenic culture of hairy roots proliferated 30 to 60-fold based on the initial fresh weight after three weeks of culture in Murashige & Skoog liquid media. Bryonolic acid as the main triterpenoid was isolated in a high yield, together with chondrillasterol from the hairy roots of this plant. Bryonolic acid showed strong inhibition of the growth of B-16 melanoma cells.

Antineoplastic Agents, Phytogenic↗

PubMed1994

[Inhibitory effect on anti-lipid IV antiserum binding activity of various synthetic oligosaccharides].

The inhibitory effects of various synthetic oligosaccharides (1-8) on anti-lipid IV antiserum binding activity were examined by ELISA (enzyme linked immunosorbent assay). Compound 8, containing an epitope GlcA-4Me beta 1-4Fuc of lipid IV, inhibited but precursors (1-5) of lipid IV did not inhibit the binding activity. In addition to the nonreducing end disaccharide derivative (6) having a methyl group at position 4 of glucuronic acid, its analogous compound (7) having no methyl groups was synthesized and their inhibition activities were compared. Moreover, the inhibitory effects of compounds (1-5) were examined using each antiserum.

Acidic Glycosphingolipids↗

PubMed1994

Comparison of the effects of dobutamine and isoproterenol in ischemic hearts by phosphorus-31 nuclear magnetic resonance spectroscopy.

We compared the effects of 2 inotropic agents, dobutamine and isoproterenol on regional coronary blood flow, contractile function, hemodynamics and levels of phosphate compounds in the acutely ischemic canine heart. Dogs were instrumented to determine regional coronary blood flow (non-radioactive microsphere method), contractile function (sonomicrometry), and hemodynamics. Myocardial phosphate compounds were measured simultaneously by the phosphate-31 (31P) magnetic resonance spectroscopic technique. Both drugs augmented the global performance of the heart, but produced no significant improvement in regional contractile function in the ischemic region. Isoproterenol significantly increased the ratio of inorganic phosphate to phosphocreatine in the ischemic region, as compared to dobutamine. However, no significant differences were seen in myocardial lactate consumption with inotropic stimulation between the 2 groups. 31P magnetic resonance spectroscopy could be used to differentiate between the effects of dobutamine and isoproterenol on energy metabolism in ischemic myocardium despite the lack of significant differences in regional function and myocardial lactate consumption. The significant tachycardia without an augmentation of systemic blood pressure induced by isoproterenol may account for this unfavorable effect on myocardial energy metabolism.

Animals↗

PubMed1994

Time course of the recovery of adenosine triphosphate content with adenosine in post-ischemic hearts--a 31P magnetic resonance spectroscopy study.

Restoration of the ATP level after brief ischemia is limited by slow de novo ATP synthesis and substrate loss in a salvage pathways for ATP synthesis, and complete recovery requires several days in the stunned heart. Adenosine is a substrate for myocardial ATP synthesis. We measured myocardial ATP in both ex vivo and in vivo experiments by 31P magnetic resonance spectroscopy (31P-MRS) and investigated the time course of ATP content recovery after application of adenosine. Guinea-pig perfused hearts were subjected to 30 min of global ischemia and reperfused for 3 h with 50 microM adenosine. The ATP level increased from 54 +/- 5% to 117 +/- 4% of the pre-ischemic value (p < 0.01). In dogs, we occluded the left anterior descending coronary artery for 40 min to produce regional ischemia. Afterwards, we administered 100 mumol/h adenosine into the left ventricle for 2 h. ATP levels increased from 63 +/- 4% to 77 +/- 5% of the pre-ischemic value with adenosine (p < 0.05). However, ATP levels did not increase for a few hours after reperfusion both ex vivo and in vivo. Our 31P-MRS studies demonstrated that brief ischemia depressed ATP levels and that administration of adenosine accelerated ATP formation in post-ischemic hearts.

Adenosine↗

PubMed1994

Compositional analysis of the oligosaccharide units of xyloglucans from suspension-cultured poplar cells.

Xyloglucan which was isolated from the walls of suspension-cultured poplar cells showed an average mol wt of 45,000; the extracellular xyloglucan is 25,000 mol wt. Compositional analysis of the oligosaccharide units with Streptomyces endo-1,4-beta-glucanase indicated that the polysaccharides were mainly constructed of four kinds of oligosaccharide repeating units, XLFG, XXFG, XXLG, and XXXG. Poplar xyloglucans contain these four units distributed at random, but primarily at the same ratio among their molecules.

Carbohydrate Sequence↗

PubMed1994

Response of hepatic proteins to 3,5,3'-tri-iodo-L-thyronine in diabetic rats.

In order to study whether peripheral action of thyroid hormones is altered in insulin deficiency and to elucidate the biological consequences of alteration of the cytosolic 3,5,3'-tri-iodo-L-thyronine (T3) binding protein (CTBP), we measured malic enzyme, T3-responsive nuclear n protein, CTBP and nuclear thyroid hormone receptor in the liver and kidney of streptozotocin (STZ)-induced diabetic rats that were treated with or without insulin and/or a receptor-saturating dose of T3. The following results were obtained. 1. Induction of malic enzyme by T3 was apparently diminished in diabetic rats. However, supplementary injection of insulin enabled previously given T3 to take effect in diabetic rats. 2. T3-responsiveness of other hepatic proteins (n protein and CTBP) was not altered by insulin in diabetic rats. 3. The level of n protein was increased by insulin in diabetic rats in vivo and in perfused rat liver, indicating that the hepatic n protein is a novel insulin-responsive protein. T3 and insulin increased the level of n protein non-synergistically in diabetic rat liver. 4. Hepatic nuclear receptor levels were not altered in diabetic rats. 5. Hepatic CTBP levels were decreased in diabetic rats. This was not due to the toxic effect of STZ. Low CTBP level was only partially increased by insulin after 30 days of diabetic period. Renal CTBP levels were not altered in diabetic rats with or without insulin treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗