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T Takeda

Publications and source records attributed to T Takeda.

At least 811 records · Page 45Linked to original sources
PubMed1991

A polyclonal-monoclonal antibody based sensitive sandwich enzyme linked immunosorbent assay for specific detection of cholera toxin.

A sensitive sandwich enzyme-linked immunosorbent assay (ELISA) for specific detection of prototype cholera toxin (CT) elaborated by Vibrio cholerae serovar O1 has been developed. The use of a high affinity monoclonal antibody (MAb) for capturing of CT epitopes permitted a high efficiency. Using this ELISA, we sought in vitro production of CT from clinical strains of V. cholerae O1, Non-O1 and from LT-producing E. coli. All culture supernatants of V. cholerae O1 were positive for CT whereas V. cholerae non-O1 and LT producing E. coli were found negative for CT. This ELISA will be particularly useful in specifically designed studies where detection of CT and not of related labile toxins is mandatory.

Animals↗
PubMed1991

Nucleosides and nucleotides. 96. Synthesis and antitumor activity of 5-ethynyl-1-beta-D-ribofuranosylimidazole-4-carboxamide (EICAR) and its derivatives.

The palladium-catalyzed cross-coupling reaction of 5-iodo-1-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)imidazole-4- carboxamide (8) with various terminal alkynes in the presence of bis(benzonitrile)palladium dichloride in acetonitrile containing triethylamine gave the desired 5-alkynyl derivatives 9 in high yields. However, when (trimethylsilyl)acetylene was used, the only isolable product was the undesired dimer, 1,2-bis(4-carbamoyl-1-beta-D-ribofuranosylimidazol-5-yl)acetylene derivative 10a. To circumvent such dimer formation, the reaction was done with use of trimethyl-[(tributylstannyl)ethynyl]silane in the absence of triethylamine to afford the desired 5-(2-trimethylsilyl)ethynyl derivative 9a in good yield. Furthermore, the similar cross-coupling reaction of 5-iodo-1-(2,3,5-tri-O-acetyl-beta-D-ribofuranosyl)imidazole-4-carboni tri le (12) with (trimethylsilyl)acetylene also afforded the desired nucleoside 13a. Deprotection of these compounds furnished 5-alkynyl-1-beta-D-ribofuranosylimidazole-4-carboxamides (6b-k) and -carbonitriles (14b-f). Among these, 5-ethynyl-1-beta-D-ribofuranosylimidazole-4-carboxamide (6b, EICAR) is the most potent inhibitor of growth of the various tumor cells in culture including human solid tumor cells. Preliminary results of in vivo antitumor activity against murine leukemias L1210 and P388 are also described.

Animals↗
PubMed1991

Endothelin-secreting tumor.

Recently, we have reported two cases with endothelin (ET)-secreting tumor presenting with hypertension and elevated plasma endothelin-1 (ET-1) levels. The present study examines the histopathology of the ET-secreting tumor in one of these cases. The neoplasm was located in the skin and microscopically characterized as a malignant hemangioendothelioma by remarkable intravascular proliferations of atypical endothelium with the expression of Factor VIII-related antigen in the tumor cells. The tumor enlarged rapidly with rising ET-1 and blood pressure levels. The ET-1 content and its messenger RNA expression in the tumor extract were higher than those from normal parts of skin. ET-1 may play a pathophysiological role in patients with ET-secreting malignant hemangioendothelioma.

Aged↗
PubMed1991

Risk determination in cases with an extra minute chromosome: prenatal diagnosis.

The interpretation of an extra minute chromosome (EMC) detected in utero presents both diagnostic and prognostic problems. Two EMC cases are presented and a flow-chart guideline is proposed for the determination of developmental risk. A prenatally detected EMC was familially inherited through a normal phenotype father. The pregnancy was continued and a normal baby boy was delivered. At one year his development was within normal ranges. The second EMC case was a mentally retarded girl examined at 4 years and 7 months of age. The EMC was identified with a combination of various staining techniques to be an inversion duplication (15). The importance of differential diagnosis of EMCs by DA/DAPI staining is emphasized.

Adult↗
PubMed1991

Can a patient with neuroblastoma be diagnosed by a single urine sample collected randomly?

We have observed that a fairly large amount of vanillylmandelic acid and homovanillic acid in urine samples taken randomly from patients with a tumor of about 10 g was less than the cutoff values and overlapped with the respective ranges of normal infants. Consequently, with only a single random urine sample there is a risk of overlooking a patient, especially in cases where the tumor is small. However, according to theoretical calculation, several random urine samples may enable us to discriminate a patient from a normal infant and can replace the 24-hour urine accumulation for 3 days which is currently performed for final judgement in the mass screening of neuroblastoma.

Homovanillic Acid↗
PubMed1991

Plasma immunoreactive endothelin-1 in experimental malignant hypertension.

We measured plasma concentrations of immunoreactive endothelin-1 (irET-1) in the prehypertensive and hypertensive phases in spontaneously hypertensive rats (SHR) and in malignant hypertension caused by deoxycorticosterone acetate (DOCA)-salt administration in SHR. We also measured concentrations of this peptide in another model of malignant hypertension, the two-kidney, one clip (2K1C) renovascular hypertensive rats chronically given caffeine. Plasma irET-1 concentrations in young (6-week-old) and mature (18-week-old) SHR did not differ from those of age-matched Wistar-Kyoto (WKY) rats. Four weeks of treatment with DOCA-salt increased blood pressure, blood urea nitrogen, serum creatinine, and plasma irET-1 in SHR but not in WKY rats. Eight weeks of DOCA-salt treatment further increased these values in SHR. Plasma irET-1 concentrations were not increased in the 2K1C rats. Six weeks of caffeine administration increased blood pressure, blood urea nitrogen, serum creatinine, plasma renin activity, and plasma irET-1 in the 2K1C rats but not in the sham-operated rats. High-performance liquid chromatographic profiles of plasma extracts pooled from these rats with malignant hypertension showed that a major component of irET-1 eluted in the position of synthetic ET-1 (1-21). Furthermore, acute hypertension induced by angiotensin II or phenylephrine did not affect the plasma irET-1 concentration in rats. The results suggested that the plasma ET-1 concentration is increased in rat models of malignant hypertension and that the high blood pressure itself is not the main factor involved in the increase of plasma ET-1.

Aging↗
PubMed1991

Endothelin-3 regulates endothelin-1 production in cultured human endothelial cells.

Effects of endothelin-3 on the secretion of endothelin-1 and other endothelium-derived substances were investigated in cultured human umbilical vein endothelial cells. The present binding study showed two distinct subpopulations of binding sites for endothelin-3 with higher and lower affinities in cultured human endothelial cells. Endothelin-3 caused an increase in intracellular Ca2+ and inositol 1,4,5-trisphosphate levels and activated protein kinase C in a dose-dependent manner. Endothelin-3 also caused an increase in [3H]thymidine incorporation into cellular DNA and stimulated the production of cyclic guanosine 3',5'-monophosphate, 6-ketoprostaglandin F1 alpha, and immunoreactive endothelin-1 in cultured human endothelial cells. NG-Monomethyl L-arginine (3 x 10(-4) mol/l) and indomethacin (10(-5) mol/l) enhanced endothelin-3-induced endothelin-1 production. These results suggest that endothelin-3 bound to its specific receptors and then caused phosphoinositide breakdown, subsequently mobilizing intracellular Ca2+ and leading to protein kinase C activation and the initiation of DNA synthesis, resulting in the stimulation of endothelin-1 production by human endothelial cells. Furthermore, this endothelin-1 production may be suppressed by endothelium-derived relaxing factor and prostacyclin produced in response to endothelin-3 in cultured human endothelial cells.

Calcium↗
PubMed1991

Inhibition by atrial and brain natriuretic peptides of endothelin-1 secretion after stimulation with angiotensin II and thrombin of cultured human endothelial cells.

We examined the inhibition by atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) of endothelin-1 secretion stimulated by angiotensin II (ANGII) and thrombin using cultured human umbilical-vein endothelial cells. ANGII and thrombin dose-dependently stimulated immunoreactive (ir) endothelin-1 secretion. Human ANP(1-28) and human BNP-32 both inhibited such secretion in a dose-dependent way. Inhibition of this secretion by ANP and BNP was paralleled by an increase in the level of cyclic guanosine 5'-monophosphate (GMP). The addition of a cyclic GMP analogue, 8-bromo cyclic GMP, reduced this stimulated secretion. Rat ANP(5-25) was weaker than human ANP(1-28) at inhibiting ir-endothelin-1 secretion and increasing cyclic GMP in the cells. ir-Endothelin-1 in the medium consisted of two components separated by high pressure liquid chromatography; the major one corresponded to endothelin-1(1-21) and the minor one corresponded to big endothelin-1(1-38). Treatment with ANP and BNP did not affect this profile. These findings suggest that human ANP and BNP inhibit endothelin-1 secretion stimulated by ANGII and thrombin in these cells through a cyclic GMP-dependent process. Taken together with endothelin stimulation of ANP and BNP secretion from the heart, our results suggest the existence of a cardiac-endothelium feedback.

Angiotensin II↗
PubMed1991

Pressure relationship between perilymph and endolymph associated with endolymphatic infusion.

The pressure difference between the perilymph and the endolymph following infusion of artificial endolymph into the endolymphatic space was studied in guinea pigs. Both the perilymphatic and the endolymphatic pressures were measured simultaneously with use of two sets of a servo-nulling system. Endolymphatic infusion caused pressure increases in both the endolymphatic and the perilymphatic spaces, but no measurable pressure difference between them. Soon after the endolymphatic infusion, both pressures returned nearly to the initial levels. We conclude that 1) the endolymphatic and the perilymphatic pressures are very closely related, and 2) if a physiologically significant pressure difference exists between endolymph and perilymph in endolymphatic hydrops, it is below the resolving power of the methods used in this study (+/- 0.1 mm Hg).

Animals↗
PubMed1991

Morphologic aspects and morphogenesis of blood cysts on canine cardiac valves.

We investigated retrospectively the morphologic aspects of blood cysts of the atrioventricular valve in eight Beagle dogs and clarified the morphogenesis of the lesions. Study of serial sections revealed that the cysts communicate with the blood vessels; however, they showed no connection with the valve surface. Immunohistochemically, the thin endothelium of the lesions showed positive staining for factor VIII-related antigen. Histologic studies of a variety of sizes of blood cysts revealed four basic stages of blood cyst formation: 1) initially, the involved blood vessel undergoes only a slight enlargement that is not grossly detectable; 2) next, the vessel becomes moderately or markedly dilated and contains a large number of erythrocytes. The changes of this stage are macroscopically detectable; and 3) then, blood flow is arrested partly in the cystic lesion, followed by degeneration and necrosis of the cyst. At this third stage, fibrous tissue or dense collagenous connective tissue is usually seen surrounding the cyst; 4) and finally, metaplastic bone is formed within the lesion. Colloidal carbon infusion into the valves of normal canine hearts revealed the presence of an extensive, dense arrangement of blood vessels in the septal leaflet of the tricuspid valve, which usually is the recognized site to develop blood cysts.

Animals↗
PubMed1991

Purification and characterization of thyroid hormone-responsive rat hepatic proteins.

Bernal et al. identified two proteins in rat hepatic nuclear extract, t- and n-proteins, that were enriched by thyroidectomy or T3 treatment, respectively. We purified these proteins, raised monospecific antibodies, and characterized them by Western blotting. Anti-n and anti-t-protein antibodies did not recognize t- and n-proteins, respectively. The n-protein was present in nuclear and cytosolic fractions, was present at low levels in the microsomal fraction, and was absent in the mitochondrial fraction of rat liver. The t-protein was more abundant in mitochondrial and microsomal fractions than in the nuclear fraction. The t-protein had the same molecular mass and shared immunological properties with peroxisomal enoyl-coenzyme-A (CoA) hydratase-3-hydroxyacyl-CoA dehydrogenase bifunctional enzyme. The total cellular amount of n-protein increased 12 h after the administration of 1 microgram T3/100 g BW to thyroidectomized rats. Induction was obvious at 0.1 microgram T3/100 g BW after 24 h. Maximal induction was observed at 0.3 microgram T3/100 g BW. The n-protein was induced when thyroidectomized rat liver was perfused with 10(-7) M T3 for 6 h, excluding the possibility that the effect of T3 was mediated by an extrahepatic factor. The n-protein was detected in liver and brain, but not in kidney, heart, testis, or spleen. However, the amount of n-protein in brain was not thyroid hormone dependent. Hepatic n-protein does not correspond to any other T3-responsive protein in terms of its molecular mass and intracellular localization and may be a novel T3-responsive protein.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1991

A novel NADPH-dependent cytosolic 3,5,3'-triiodo-L-thyronine-binding protein (CTBP; 5.1S) in rat liver: a comparison with 4.7S NADPH-dependent CTBP.

A novel NADPH-dependent cytosolic 3,5,3'-triiodo-L-thyronine (T3)-binding protein (CTBP) was purified by sequential fractionation of rat liver cytosol on Q-Sepharose, phenyl-Sepharose, red-Sepharose, and polyacrylamide gel electrophoresis under nondenaturing conditions. The CTBP had a sedimentation coefficient of 5.1S, a Stokes' radius of 35 A, and a calculated mol wt of 76,000. The apparently homogenous protein consisted of a dimer of a polypeptide chain with a mol wt of 38,000 as estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. NADPH increased both the affinity and maximal binding capacity for T3 in the 5.1S CTBP. The maximal activity to bind T3 was obtained by 3.0 x 10(-8) M NADPH. The calculated maximal affinity constant was 2.4 x 10(9) M-1, and the maximal binding capacity was 21,000 pmol T3/mg 5.1S CTBP. The order of affinity of iodothyronine analogs to the 5.1S CTBP was as follows: D-T3 greater than L-T3 greater than L-T4 greater than triiodothyroacetic acid. The optimal pH for T3 binding was 7.2-7.5. Ca2+, Mg2+, and Mn2+ (0.1-10 mM) did not influence T3 binding to CTBP. Zn2+ (1.0 mM), however, inhibited the binding. These results suggested that 5.1S NADPH-dependent CTBP, which is distinct from 4.7S CTBP that had been purified in our laboratory from rat kidney, is present in rat liver.

Animals↗
PubMed1991

Ontogenesis of the high affinity NADPH-dependent cytosolic 3,5,3'-triiodo-L-thyronine-binding protein in rat.

Studies were undertaken to define the concentration of the high affinity NADPH-dependent cytosolic 3,5,3'-triiodo-L-thyronine (T3)-binding protein (CTBP) in various tissues of adult rats and in those of developing rats. The maximal binding capacity (MBC) for T3 binding was calculated from the data obtained by Scatchard analysis of T3 binding to the charcoal-extracted cytosol in the presence of 50 microM NADPH. There were no significant differences in the affinity constant among various tissues, whereas the MBC was different among tissues in adult rats. When the levels of MBC were expressed by moles/DNA concentration, the order was as follows; kidney greater than heart greater than or equal to cerebrum greater than or equal to liver much greater than testis greater than cerebellum greater than spleen. The CTBP was not detected before birth in liver, heart, and spleen. The CTBP in these tissues emerged 5 days after the birth, and increased during 6 weeks after the birth. The CTBP in kidney was not detected before birth but was detected at the time of birth. The level of MBC in kidney increased during 3 weeks after the birth. In contrast, the CTBP was detected 5 days before birth, and the level of MBC increased at the time of birth both in cerebrum and cerebellum. The MBC in cerebrum gradually decreased after birth, but began to increase again 2 weeks after the birth. The level of MBC in cerebellum did not increase again. These results suggested that the target tissues of thyroid hormone are enriched with NADPH-dependent CTBP, and that the changes in the concentration of the CTBP are related to the growth of tissues. It was speculated that the CTBP has a specific function in cerebrum at the time of birth although the action of the CTBP is not certain.

Animals↗
PubMed1991

The complete amino acid sequence of an abortifacient protein, karasurin.

The complete amino acid sequence of a new abortifacient protein, karasurin, was determined. Karasurin, which was isolated from fresh root tubers of Trichosanthes kirilowii Maximowicz var, japonicum Kitamura (Cucurbitaceae), was a highly basic protein with pI 10.1 and molecular weight of 28,000. Intact karasurin was cleaved with cyanogen bromide, lysyl endopeptidase, formic acid and 2-(2'-nitrophenyl-sulfenyl)-3-methyl-3-bromoindolenine (BNPS-skatole), respectively. Cleavages with N-bromosuccinimide (NBS), trypsin and pepsin were performed for the fragments. The resultant peptide fragments were separated by gel filtration chromatography, reversed-phase high performance liquid chromatography (HPLC) or gel filtration HPLC following sequence analyses by automated Edman methods. Karasurin consists of 246 or 247 amino acid residues with a calculated molecular weight of 27,144 or 27,215 differing only at the C-terminus with the addition of alanyl residue. Two C-terminal sequences were identified as Asn-Asn-Met-OH and Asn-Asn-Met-Ala-OH by sequence analyses and hydrazinolysis, but there was no micro-heterogeneity in other peptides analysed. The sequence of karasurin revealed a considerable similarity to that of trichosanthin and alpha-trichosanthin, which are known as abortifacient, ribosome-inactivating and anti human immunodeficiency virus (HIV) (the virus causing acquired immunodeficiency syndrome (AIDS) proteins, with 93% and 98% identity, respectively.

Abortifacient Agents, Nonsteroidal↗
PubMed1991

Presence of protein polymorphism in karasurin, an abortifacient and anti-tumor protein, identified with physicochemical properties.

Karasurin is an abortifacient plant protein isolated from fresh root tubers of Trichosanthes kirilowii Maximowicz var. japonicum Kitamrra (Cucurbitaceae). This study describes the presence of protein polymorphism in karasurin (karasurin-A and karasurin-B) separated by ion-exchange chromatography. Two components showed no differences in the molecular weight (ca. 28000), the amino acid composition, the neutral sugar content and part of the amino acid sequence. A unique difference was observed in their isoelectric points (10.1 for karasurin-A and 10.2 for karasurin-B). However, modifications of glycosylation or phosphorylation were not found. Biological assays for inducing mid-term abortion in pregnant mice and inhibition of the growth of BeWo cells gave no significant differences between them. The presence of protein polymorphism in karasurin, whose biological significance is not yet understood, is a first finding among several abortifacient proteins.

Abortifacient Agents, Nonsteroidal↗
PubMed1991

The nephritogenic glycopeptide from rat glomerular basement membrane. X. Synthesis of an N-triglycosyl dipeptide and characteristics of its cis-trans isomers.

Isomers of O-alpha-D-glucopyranosyl-(1----6)-O-beta-D-glucopyranosyl- (1----6)-N-[L-aspart-1-oyl-(L-proline)-4-oyl]-alpha-D-glucopyranos ylamine have been prepared, as models for a derivative possibly present in the glomerular basement membrane of rats, by condensation of the corresponding dipeptide derivative (5) with triglycosylamine (4) in the presence of O,O-diethylcyanophosphonate, followed by deprotection of the trisaccharide-dipeptide derivative. During the deprotection process, cis- and trans-isomers containing proline were separated by silica gel column chromatography and also reversed-phase high performance liquid chromatography.

Amino Acid Sequence↗