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Biomedical subjects

T Yasuda

Publications and source records attributed to T Yasuda.

At least 595 records · Page 33Linked to original sources
PubMed1991

Geometry of adult rat sensory neurons in culture; its modulation by laminin.

Geometrical analysis of highly-purified and low-density adult rat dorsal root ganglion (DRG) neuron culture proved that laminin enhanced the total neurite length and the maximal extension of neurites, but did not significantly increase the neurite branching nor soma size particularly after 4 days of culture. Survival rates of adult DRG neurons were not affected by laminin. These results suggest that laminin is a potent modulator of neurite geometry in adult rat DRG neurons, which promotes neurite elongation rather than neurite branching.

Animals↗
PubMed1991

Use of inactive beta-D-galactosidase for elimination of interference by anti-beta-D-galactosidase antibodies in immune complex transfer enzyme immunoassay for anti-thyroglobulin IgG in serum using beta-D-galactosidase from Escherichia coli as label.

A novel enzyme immunoassay (immune complex transfer enzyme immunoassay) for anti-thyroglobulin IgG using beta-D-galactosidase from Escherichia coli as label was reported previously. This immunoassay was highly sensitive in demonstrating anti-thyroglobulin IgG not only in all patients with Graves' disease and chronic thyroiditis but also in a large proportion of healthy subjects. However, the detection of anti-thyroglobulin IgG at low levels in some serum samples was difficult, probably due to the presence of anti-beta-D-galactosidase antibodies. In the present study, the use of inactive beta-D-galactosidase was tested for elimination of interference by anti-beta-D-galactosidase antibodies. Preincubation of serum samples with excess of inactive beta-D-galactosidase resulted in sufficiently low backgrounds to detect low levels of anti-thyroglobulin IgG with little effect on the dose-response of anti-thyroglobulin IgG. As a result, it was revealed that anti-thyroglobulin IgG was present in almost all healthy subjects as well as all patients with Graves' disease and chronic thyroiditis.

Adult↗
PubMed1991

X-ray structural studies and physicochemical characterization of (E)-6-(3,4-dimethoxyphenyl)-1-ethyl-4-mesitylimino-3-methyl- 3,4-dihydro-2(1H)-pyrimidinone polymorphs.

The polymorphism of (E)-6-(3,4-dimethoxyphenyl)-1-ethyl-4-mesitylimino-3-methyl-3,4-di hydro- 2(1 H)-pyrimidinone (FK664; 1) was characterized by using X-ray powder diffractometry, differential scanning calorimetry (DSC), and IR spectroscopy. Structures of two polymorphs (Forms A and B) were determined by X-ray crystallographic analysis. Form A crystallized in the monoclinic space group P2(1)/c, with a = 13.504(2), b = 6.733(1), c = 24.910(8) A, beta = 96.55(4) degrees, z = 4, and dcal = 1.203 g/cm3, while Form B crystallized in the same space group, with a = 8.067(2), b = 15.128(4), c = 18.657(4) A, beta = 102.34(3) degrees, z = 4, and dcal = 1.216 g/cm3. The conformational features of 1 were very similar between the two polymorphs. Compound 1, in both crystal forms, took an energetically reasonable conformation in three rigid planes, such as 2-pyrimidone, trimethylphenyl, and dimethoxyphenyl rings, but the molecules were packed in different ways between the two polymorphs. In the Form B crystal, a short contact was possible, to form pi-pi interactions between two dimethoxyphenyl groups related with the inversion center in the crystal lattice; this interaction seems to contribute to stabilizing the crystal structure of Form B. Both Forms A and B showed only one endothermic peak due to fusion at 115 and 140 degrees C, respectively, on the DSC thermograms; therefore, it is suggested that there are no transition points between the two polymorphs. The heats of fusion obtained from the DSC thermograms were 33.2(2) kJ/mol for Form A and 36.8(1) kJ/mol for Form B.(ABSTRACT TRUNCATED AT 250 WORDS)

Chemical Phenomena↗
PubMed1991

Human peripheral nerve sheath neoplasm: expression of Schwann cell-related markers and their relation to malignant transformation.

We immunohistochemically examined the expression of Schwann cell-related markers, nerve growth factor (NGF) receptor, S-100 alpha- and beta-proteins, glial fibrillary acidic protein (GFAP), and galactocerebroside (gal C) in 5 malignant schwannomas, 21 benign peripheral nerve sheath tumors, and 4 apparently normal sural nerves. NGF receptor was expressed in the malignant schwannomas and benign peripheral nerve sheath tumors, but not in the endoneurium of apparently normal peripheral nerves. S-100 alpha-protein was observed in malignant schwannomas and in some neurofibroma cells. All cases were strongly positive for S-100 beta-protein but were negative for GFAP and gal C. Our results suggest that these Schwann cell-related markers may be useful in identifying peripheral nerve sheath neoplasma as well as their malignant transformation.

Adult↗
PubMed1991

Myocardial accumulation and clearance of technetium 99m teboroxime at 100%, 75%, 50% and zero coronary blood flow in dogs.

Sequential changes in the regional distribution of technetium 99m Teboroxime (SQ30217) were evaluated in nine dogs with graded coronary artery stenosis, occlusion and reperfusion of either the left anterior descending or left circumflex arteries. 99mTc-Teboroxime accumulation recorded by planar imaging was compared with directly measured coronary blood flow (Doppler) and regional myocardial perfusion (microspheres). Serial images were recorded beginning at the time of injection and continuing for the next 18 min. The data were summed from minutes 2-3, 3-6, 4-8 and 9-18 after injection for comparison with the other parameters. Myocardial clearance of Teboroxime was analysed at each level of blood flow. There was a linear relationship between the Teboroxime activity ratio (abnormal/normal) and coronary blood flow (r = 0.96) and regional myocardial perfusion (r = 0.99). Zones of diminished perfusion were least apparent in the summed images recorded during minutes 2-3. In later images, the lesions were well visualized. The myocardial clearance half-times at 100%, 75% and 50% flow were not significantly different, while clearance half-time at total occlusion was significantly (P less than 0.01) faster. In the 3-6, 4-8 and 9-18 minutes summed images, the Teboroxime activity ratio increased significantly (P less than 0.01) after reperfusion compared with total occlusion.

Animals↗
PubMed1991

Genetic polymorphism of human glutamate oxaloacetate transaminase (GOT1) detected using isoelectric focusing and a sensitive and positive staining method.

Genetic polymorphism of glutamate oxaloacetate transaminase (GOT1) was demonstrated in human erythrocytes by isoelectric focusing in thin layer polyacrylamide gels and a sensitive and positive detection method. Using this technique, five phenotypes, GOT1 1, 2, 2-1, 3-1 and 3-2 were determined and the estimated gene frequencies of GOT1*1, GOT1*2 and GOT1*3 in the Japanese population were 0.9740, 0.0173 and 0.0087, respectively.

Aspartate Aminotransferases↗
PubMed1991

Transferrin subtyping of bloodstains and semen using isoelectric focusing and immunoblotting.

Transferrin (TF) subtyping was carried out on bloodstains that had been made on cotton sheeting and stored under a variety of conditions ranging from -20 degrees C to +37 degrees C. The time limit of detection was longer than 54 weeks after dry storage under each condition. Moreover the correlation between isoprotein types of the TF in blood and semen samples from the same individual was determined in 103 men. All three TF common types and two rare types in all semen samples correlated with the type found in the corresponding blood sample. A combination of isoelectric focusing separation and immuno-enzyme-linked detection may prove to be very useful for forensic TF subtyping.

Blood Stains↗
PubMed1991

Nasal administration of salmon calcitonin for prevention of glucocorticoid-induced osteoporosis in children with nephrosis.

To determine the effect of intranasal administration of salmon calcitonin on glucocorticoid-induced osteoporosis in children with nephrosis, we gave 100 U of calcitonin intranasally on alternate days with 1 alpha-hydroxyvitamin D3 to five children, 8 to 12 years of age, with frequently relapsing nephrosis. Four patients with osteoporosis, 10 to 14 years of age, were treated only with 1 alpha-hydroxyvitamin D3 and served as control subjects. Both groups were treated with an almost equal amount of glucocorticoids previously and during this study period. Bone mineral content of the spine was measured by a quantitative computed tomographic technique. The bone mineral content was preserved in both cortical and spongeous areas of the vertebrae during the 16-month period in the calcitonin-treated group but was decreased significantly in the control group. Urinary hydroxyproline and calcium excretion decreased significantly in the calcitonin-treated group. The serum calcium and phosphorus concentrations and the parathyroid function did not change significantly in either group. We conclude that calcitonin suppressed bone resorption and might be useful for the long-term treatment of osteoporosis, in combination with 1 alpha-hydroxyvitamin D3, in children with nephrosis requiring long-term glucocorticoid therapy.

Administration, Intranasal↗
PubMed1991

Molecular definition of human beta 2-glycoprotein I (beta 2-GPI) by cDNA cloning and inter-species differences of beta 2-GPI in alternation of anticardiolipin binding.

Human beta 2-glycoprotein I (beta 2-GPI) is involved in cardiolipin (CL) binding of anticardiolipin antibodies (aCL) in systemic lupus erythematosus (SLE). We examined the inter-species differences of beta 2-GPI in alternation of CL binding of aCL. beta 2-GPI preparations were obtained from human, bovine, and rat sera by sequential CL--polyacrylamide affinity, DEAE--cellulose, and anti-human IgG-conjugated Sepharose CL-4B column chromatography, and they had apparent molecular weights of 50, 53, and 55 kDa respectively. Human beta 2-GPI not only enhanced CL binding by aCL in SLE but also depressed it by those in syphilis. Either bovine and rat beta 2-GPI exerted no or quite small inhibition of the binding of syphilitic aCL compared with human beta 2-GPI whereas all three species of beta 2-GPI generated binding of aCL in SLE to a similar degree. Further, a complete cDNA clone, p beta 2-GPI, was isolated from a human hepatoma cell line, HepG2, and its nucleotide sequence was analyzed. The sequences of bovine and rat counterpart molecules (beta 2-GPI) are highly homologous to that of the deduced sequence, and their corresponding regions are 84.0 and 82.5% identical to the complete domain and to the amino acid sequence 53-326 of human beta 2-GPI respectively. One of major differences appears at position 154 in human beta 2-GPI, and might be associated with the inhibitory effect on the binding of syphilitic aCL. The sequencing analysis of these beta 2-GPI proteins might provide leads to functional sites of domains which would be associated with such serological phenomena.

Amino Acid Sequence↗
PubMed1991

Purification and characterization of genetically polymorphic deoxyribonuclease I from human kidney.

Deoxyribonuclease I (DNase I) was purified about 850,000-fold from human kidney using a rabbit anti-human urine DNase I antibody and sensitive DNase I activity assay. On SDS-PAGE, the purified kidney DNase I gave a single major band, and its molecular mass was estimated to be 38,000 Da. The activity of purified kidney DNase I was dependent on the presence of Mg2+ and Ca2+. G-Actin inhibited the activity, as did the anti-urine DNase I antibody. The properties of the kidney DNase I were the same as those of urine DNase I.

Actins↗
PubMed1991

Production of monoclonal antibodies specific for ganglioside GD3.

Four kinds of anti-GD3 monoclonal antibodies, DSG-1, -2, -3, and -4, of the IgM class were obtained by the immunization of BALB/c mice with enzootic bovine leukosis tumor tissue-derived ganglioside GD3 inserted into liposomes with Salmonella minnesota R595 lipopolysaccharides. The specificities of the monoclonal antibodies obtained were defined by complement-dependent liposome immune lysis assay and by enzyme immunostaining on thin-layer chromatography. The reactivities of the monoclonal antibodies obtained to four ganglioside GD3 variants [GD3(NeuAc-NeuAc), GD3(NeuAc-NeuGc), GD3(NeuGc-NeuAc), and GD3(NeuGc-NeuGc)] were tested. All of the monoclonal antibodies were found to react with GD3(NeuAc-NeuAc) and GD3(NeuAc-NeuGc) but not with GD3(NeuGc-NeuAc) or GD3(NeuGc-NeuGc). Furthermore, various purified glycosphingolipids were used to determine the specificity of these monoclonal antibodies. All 4 antibodies reacted only with ganglioside GD3 [GD3(NeuAc-NeuAc) and GD3(NeuAc-NeuGc)], but not with several gangliosides linking the GalNAc, Gal beta 1-3GalNAc, NeuAc alpha 2-3Gal beta 1-3GalNAc, or NeuAc alpha 2-8NeuAc alpha 2-3Gal beta 1-3GalNAc residue to the Gal moiety of ganglioside GD3 (GD2, GD1b, GT1b, or GQ1b, respectively), ganglioside GT1a having the same terminal NeuAc alpha 2-8NeuAc alpha 2-3Gal residue as ganglioside GD3, other gangliosides, and neutral glycosphingolipids. These findings suggest that the 4 monoclonal antibodies obtained may be specific for the epitope of NeuAc-alpha 2-8Sia alpha 2-3Gal beta 1-4Glc residue of ganglioside GD3.

Animals↗
PubMed1991

Differentiation of regional perfusion and fatty acid uptake in zones of myocardial injury.

The relative myocardial distribution of 201Tl and modified fatty acid (123I-labelled 3-methyl-p-[iodo]-phenyl pentadecanoic acid, MFA) was determined in eight patients with unstable angina (UA) and six patients with acute myocardial infarction treated with reperfusion therapy within 4.1 h (MI). The results of radionuclide imaging were correlated with coronary angiography and quantitative left ventriculography performed within 10 days of the radionuclide procedures. Zones of injury were identified as areas with diminished 201Tl uptake distal to sites of coronary narrowing. A nearly parallel reduction in regional fatty acid concentration was observed in these areas. Comparison of the regional distributions of the two agents revealed subtle differences in their distributions in the ischaemic zones. Three patterns were recognized: (a) MFA uptake greater than Tl (MFA greater than Tl), (b) matched decrease of MFA and Tl (MFA = Tl), (c) MFA uptake less than Tl (MFA less than Tl). Seven of eight patients with UA had normokinesis or hypokinesis on quantitative left ventriculography. Five of the seven showed the MFA greater than Tl pattern, while one had the MFA less than Tl pattern and one had the MFA = Tl pattern. The eighth patient with UA had akinesis and the MFA = Tl pattern. All six patients with acute infarction had akinesis on ventriculography. One of these patients had the MFA greater than Tl pattern, two had the MFA = Tl pattern and three had the MFA less than Tl pattern. These results suggest that fatty acid and thallium have grossly similar distributions in areas of acute myocardial ischaemia. On careful inspection, zones of slight relative excess fatty acid concentration are observed more often in areas of acute ischaemia with normal wall motion.

Adult↗
PubMed1991

Significance of inducible cephalosporinase remaining in the experimentally infected rat granuloma pouch after beta-lactam therapy.

We studied the influence of inducible cephalosporinase on levels of secondarily administered beta-lactam antibiotics in exudates using experimentally infected rat granuloma pouches. Cefoperazone or cefmetazole was administered intramuscularly at a dose of 100 mg/kg of body weight to rats at 2 and 8 h after infection of rat pouches with Serratia marcescens W-24, which possesses an inducible type I beta-lactamase (cephalosporinase). Subsequently, cefotaxime or cefbuperazone was administered at an intravenous dose of 100 mg/kg to rats at 24 h postinfection. Levels of cefotaxime in the pouch exudates of the cefmetazole-pretreated group were lower than those in the control group, which was infected but not pretreated with antibiotics. This was due to the inactivation of cefotaxime by extracellular cephalosporinase which was induced by cefmetazole and which remained in the rat pouches. However, cefotaxime concentrations were not reduced in the cefoperazone-pretreated group because of the low inducibility of cefoperazone against cephalosporinase production. On the other hand, cefbuperazone concentrations were similar in all groups (control, cefoperazone pretreated, and cefmetazole pretreated), because cefbuperazone is more stable against this enzyme than cefotaxime is. In conclusion, concentrations of secondarily administered beta-lactam antibiotics are affected by inducibly produced cephalosporinase at the infection site when a good inducer like cefmetazole is administered beforehand.

Animals↗
PubMed1991

Kistrin, a polypeptide platelet GPIIb/IIIa receptor antagonist, enhances and sustains coronary arterial thrombolysis with recombinant tissue-type plasminogen activator in a canine preparation.

BACKGROUND: Kistrin is a 68-amino acid polypeptide from the venom of the Malayan pit viper Agkistrodon rhodostoma, which inhibits the platelet GPIIb/IIIa receptor. Its effect on thrombolysis, reocclusion, and bleeding associated with administration of recombinant tissue-type plasminogen activator (rt-PA) was studied in a canine model of coronary artery thrombosis. METHODS AND RESULTS: Coronary patency was monitored for 2 hours by ultrasonic flow probe and repeated coronary angiography. The rt-PA was given as 0.45-mg/kg bolus injections at 15-minute intervals until recanalization or to a maximum of four boluses. Four groups of four or five dogs were studied: a control group that received intravenous heparin (4,000-unit bolus and 1,000 units each hour) and three groups that received heparin and 0.48, 0.24, or 0.12 mg/kg kistrin, administered as a 10% bolus injection and an infusion during a 60-minute period. In the control group, reflow occurred in four of five dogs within 37 +/- 47 minutes but was followed by cyclic reflow and reocclusion. Kistrin at a dose of 0.48 and 0.24 mg/kg reduced the time to reflow to 6 +/- 5 and 10 +/- 3 minutes, respectively, and abolished reocclusion. With 0.12 mg/kg kistrin, reflow occurred in all four animals, within 27 +/- 23 minutes, and reocclusion occurred in two animals. Kistrin induced a dose-related prolongation of the template bleeding time: with 0.48 mg/kg kistrin, the bleeding time was prolonged from 3.8 +/- 1.3 minutes before infusion to 29 +/- 2 minutes during infusion, but it was shortened to 8.3 +/- 2.6 minutes at 90 minutes after the end of infusion. Kistrin also caused a dose-related inhibition of platelet aggregation with ADP and collagen: with 0.48 mg/kg kistrin, platelet aggregation was abolished during the infusion but had partially recovered toward the end of the observation period. Pathological examination of recanalized coronary arterial segments of dogs given 0.48 or 0.24 mg/kg kistrin revealed widely patent arteries with some platelets layered on the damaged intimal surface. CONCLUSIONS: Kistrin increases the rate and extent of thrombolysis with a reduced dose of rt-PA, and it prevents reocclusion. At an effective dose, it is associated with a transient prolongation of the bleeding time and inhibition of platelet aggregation. Kistrin may offer promise as adjunctive treatment to thrombolytic agents in patients with acute myocardial infarction.

Animals↗
PubMed1991

Novel detection method for human protein C inhibitor (PCI) using immunoblotting with antibodies specific to synthetic peptides corresponding to the N-terminal and C-terminal amino acid sequences of human PCI.

Three types of antibody, which were specific to the purified human protein C inhibitor (PCI) and to two synthetic peptides, which corresponded to the N-terminal 15 amino acid residues (PCI-N) and C-terminal 15 residues (PCI-C) of PCI, were produced. Plasma PCI patterns, which were shown by means of polyacrylamide gel isoelectric focusing followed by immunoblotting with the antibody to purified PCI, were almost identical to those obtained with the antibodies to the peptides, PCI-N and PCI-C. The latter antibodies against the synthetic peptides proved very useful for biochemical or genetic analysis of human plasma PCI, as such peptide antigens could be produced without any of the tedious procedures necessary to obtain purified PCI as an immunogen.

Amino Acid Sequence↗