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Biomedical subjects

T Yasuda

Publications and source records attributed to T Yasuda.

At least 505 records · Page 28Linked to original sources
PubMed1993

Solvent dependence of optical rotation of (S)-N-[1-(2-fluorophenyl)- 3,4,6,7-tetrahydro-4-oxo-pyrrolo[3,2,1-jk][1,4]benzodiazepine-3-yl]- 1H-indole-2-carboxamide.

A new cholecystokinin-A antagonist, (S)-N-[1-(2-fluorophenyl)- 3,4,6,7-tetrahydro-4-oxo-pyrrolo[3,2,1-jk][1,4]benzodiazepine-3-yl]- 1H-indole-2-carboxamide (FR120480; 1), is a chiral compound that shows considerable solvent dependence of its optical rotation. Not only the absolute values, but also the signs (+ or -) for this compound change in various solvents. The optical rotation of 1 inherently correlated to the electron donating property characterized by donor number of the solvent. The 1H NMR study implied that hydrogen bonds were formed between electron donor groups of the solvents and the NH groups of indole and amide of 1. In accordance with the NMR results, X-ray crystallography of the tetrahydrofuran solvate of 1 showed that hydrogen bond formation occurred between the oxygen atom of tetrahydrofuran and the amide group of 1.

Benzodiazepinones↗
PubMed1993

Nonurea sodium dodecyl sulfate-polyacrylamide gel electrophoresis with high-molarity buffers for the separation of proteins and peptides.

A sodium dodecyl sulfate-polyacrylamide gel electrophoresis with a discontinuous buffer system for separation of both peptides and proteins, which is a modification of the Laemmli system, is described. In the modified procedure, twofold higher concentrations of buffers in the separating gel and the running buffer solution allow superior resolution for peptides as small as M(r) 5000. The resolution of peptides was dependent on salt concentrations in the systems in which sodium chloride was partially substituted for Tris-HCl buffer and buffer concentrations were varied. In the stacking gel of the modified procedure, detection of peptides and SDS demonstrated a sharp stack of peptides at the trailing edge of the SDS stack. On the other hand, this SDS stack included peptides, forced them to diffuse, and produced a broad starting zone under Laemmli conditions. In addition, following expansion of the SDS stack impaired peptide resolution further in the separating gel. Accordingly, the different interaction with the SDS stack in the stacking process was found to produce different resolution of peptides in the electrophoretic procedures. The modified conditions have potential to provide a superior alternative to the Laemmli system for analysis of various proteins.

Buffers↗
PubMed1993

Activity measurement and multiplicity detection of human secretory-type ribonuclease based on polycytidylic acid/ethidium bromide fluorescence.

Two analytical methods for human secretory-type ribonuclease, which are based on polycytidylic acid/ethidium bromide fluorescence, have been developed. The first is a method for measurement of secretory-type ribonuclease activity utilizing the radial diffusion of ribonuclease in a thin agarose gel plate containing polycytidylic acid and ethidium bromide. Ribonuclease activity was visualized as a dark circle on a fluorescent background under ultraviolet light after immersing the gel in a cooled acidic solution. The radius of the dark circle was proportional to the amount of the enzyme. This method allows quantitation of human secretory-type ribonuclease down to at least 5 x 10(-5) unit, which corresponds to 60 pg. Secretory-type ribonuclease activity in 18 different human tissues and body fluids was measured. The second method is a zymogram technique for detection of secretory-type ribonuclease after isoelectric focusing, which includes placing a dried agarose film containing polycytidylic acid and ethidium bromide on the focused gel. Human secretory-type ribonuclease (less than 3 x 10(-4) unit) was detected with a high band resolution on the same principle as that of the activity assay described above.

Body Fluids↗
PubMed1993

Chronic progressive sensory ataxic neuropathy: clinicopathological features of idiopathic and Sjögren's syndrome-associated cases.

Eleven patients with chronic progressive sensory ataxic neuropathy were examined clinicopathologically. Three cases were associated with primary Sjögren's syndrome (SS-SAN) and the others were considered to be idiopathic (ISAN). The major clinical symptom in both was loss of proprioceptive and kinesthetic sensation with some impairment of superficial sensation, with multifocal and asymmetrical distribution and progression. The truncal and trigeminal nerves were frequently involved. The motor system was substantially preserved. These somatic sensory and motor symptoms did not differ between ISAN and SS-SAN, but autonomic nervous system signs were more frequent in SS-SAN. Polyclonal elevations of serum IgG and/or IgA were seen in 8 patients. One autopsied case with ISAN combined with previous reports suggested that systemic T- and B-cell infiltration into the nervous tissues, as well as a wide variety of the visceral organs, may be a common finding in ISAN and SS-SAN, and could participate in the cause of this neuropathy and polyclonal hypergammaglobulinaemia.

Aged↗
PubMed1993

Postmortem concentrations of thiopental in tissues: a sudden death case.

High-performance liquid chromatography was employed to determine the concentration of thiopental in body fluids and tissues in an individual who had died due to intravenous injection of the clinical dose. The blood concentration of thiopental was 0.6 mg/l. Among the 10 tissues examined, the brain and thymus showed the highest level of the drug; 11.9 mg/kg and 7.66 mg/kg, respectively. The results are discussed in the light of the relevant literature.

Adult↗
PubMed1993

Subclinical phenotypic expressions in heterozygous females of X-linked recessive bulbospinal neuronopathy.

Four of 8 definite heterozygous female carriers determined by PCR amplification of tandem CAG repeat of the AR gene, from 4 families of X-linked recessive bulbospinal neuronopathy (X-BSNP) showed extensive high amplitude motor unit potentials in examined muscles although all subjects were neurologically normal. Plasma creatine kinase, myoglobin, myosin light chain, lactate and pyruvate were all normal even in the carriers who showed EMG abnormalities. Muscle biopsy showed a type 2 fiber preponderance and possible very mild type 2 fiber grouping in a carrier with an EMG abnormality. These results suggest that a mutant AR gene may express subclinical phenotypic manifestations in a subpopulation of the heterozygous females of X-BSNP.

Action Potentials↗
PubMed1993

Cerebrospinal fluid 28-kDa calbindin-D as a possible marker for Purkinje cell damage.

To examine the clinical value of 28-kDa calbindin-D (CaBP) in cerebrospinal fluid (CSF) as a marker for the damage to Purkinje cells, we measured CSF CaBP levels using an enzyme immunoassay method in 107 patients with cerebellar and other neurological diseases, and 26 controls. The mean CaBP level was markedly elevated in patients with cerebellar diseases, and the elevation of CaBP level was more frequent in the diseases involving Purkinje cells, such as multiple system atrophy (MSA) and subacute cerebellar degeneration in association with lung cancer. Further, in MSA patients, the CaBP levels decreased with duration of illness. The mean levels of CaBP were also elevated in some of the other diseases. We conclude that the elevations of CaBP levels are not specific for cerebellar diseases, but CSF CaBP may be a useful marker for examining the Purkinje cell involvement in cerebellar diseases.

Adolescent↗
PubMed1993

Evidence for a rebound coagulation phenomenon after cessation of a 4-hour infusion of a specific thrombin inhibitor in patients with unstable angina pectoris.

OBJECTIVES: In a Phase I clinical trial, we studied the antithrombotic and clinical effects of the synthetic competitive thrombin inhibitor, argatroban, in 43 patients with unstable angina pectoris. BACKGROUND: Thrombin has a pivotal role in platelet-mediated thrombosis associated with atheromatous plaque rupture in patients with an acute ischemic coronary syndrome. However, the efficacy of conventional heparin therapy to prevent ischemic events is limited and has been surpassed by that of specific thrombin inhibitors in experimental models of arterial thrombosis. METHODS: Intravenous infusion of the drug (0.5 to 5.0 micrograms/kg per min) for 4 h was monitored by sequential measurements of coagulation times and of indexes of thrombin activity in vivo followed by a 24-h clinical observation period. RESULTS: Significant dose-related increases in plasma drug concentrations and activated partial thromboplastin times (aPTT), but no bleeding time prolongation or spontaneous bleeding, was observed. Myocardial ischemia did not occur during therapy but, surprisingly, 9 of the 43 patients experienced an episode of unstable angina 5.8 +/- 2.6 h (mean +/- SD) after infusion. This early recurrent angina was correlated significantly with a higher argatroban dose and with greater prolongation of aPTT but not with other demographic, clinical, laboratory and angiographic characteristics. Pretreatment plasma concentrations of thrombin-antithrombin III complex and fibrinopeptide A were elevated two to three times above normal values. During infusion, thrombin-antithrombin III complex levels remained unchanged, whereas a significant 2.3-fold decrease in fibrinopeptide A concentrations was observed. By contrast, 2 h after infusion, thrombin-antithrombin III complex concentrations increased 3.9-fold over baseline measurements together with return of fibrinopeptide A levels to values before treatment with argatroban. CONCLUSIONS: In patients with unstable angina, argatroban inhibits clotting (aPTT prolongation) and thrombin activity toward fibrinogen (fibrinopeptide A decrease), but in vivo thrombin (thrombin-antithrombin III complex) formation is not suppressed. However, cessation of infusion is associated with rebound thrombin (thrombin-antithrombin III complex) generation and with an early dose-related recurrence of unstable angina. Although the mechanism of this clinical and biochemical rebound phenomenon remains to be determined, its implication for the clinical use of specific thrombin inhibitors in the management of ischemic coronary syndromes may be significant.

Aged↗
PubMed1993

Active oxygen-induced modification alters properties of collagen as a substratum for fibroblasts.

Acid-soluble collagen from rat skin was modified by active oxygen in vitro, and properties of the modified collagen as a substratum for fibroblasts were studied. When collagen was treated with ascorbate-copper ion systems, cross-linking and a little degradation occurred rapidly. The cells attached but spread poorly on the modified collagen gel as compared with on the untreated collagen gel. On the other hand, when collagen was treated with H2O2-copper ion systems, only degradation of collagen molecule occurred rapidly. This treatment did not affect the attachment and spreading of the cells on the collagen gel, but when the incubation was continued for a long time, the cells migrated actively and gathered. Thymidine incorporation by the cells was suppressed on both modified collagen gels as compared with that on untreated collagen gel, and the extent of the suppression on the H2O2-copper-treated collagen was larger than that on the ascorbate-copper-treated collagen. These results indicate that the active oxygen-induced cross-linking and degradation significantly alter properties of collagen as a substratum for fibroblasts.

Animals↗
PubMed1993

Successful reconstruction of a high-pressure injection injury of the hand using a first web flap of the foot.

High-pressure injection injury to the hand often results in loss of tissue and hand function. The successful reconstruction of a hand following high-pressure injection injury is reported. A free neurovascular flap was transferred from the first web space of the foot to cover a skin defect in the first web space area of the hand. The digital nerves of the thumb and index finger were repaired using sural nerve grafts.

Adolescent↗
PubMed1993

Suppressive effect of liposomes containing DNA coding for diphtheria toxin A-chain on cells transformed with bovine leukemia virus.

A recombinant plasmid which contained a gene for diphtheria toxin A-chain (DT-A) under the control of the long terminal repeat (LTR) of bovine leukemia virus (BLV) (BLV-LTR) was constructed to test a novel application of liposomes as antiviral agents. The promoter activity of BLV-LTR was estimated by the chloramphenicol acetyltransferase (CAT) assay using a plasmid which contains the coding sequence of CAT under the control of BLV-LTR (pBLVCAT). When BLV-infected cells were transfected with pBLVCAT, CAT activity was detected. BLV-uninfected cell lines, however, showed no detectable CAT activity. The plasmid DNA entrapped in liposomes was added to BLV-infected cells in culture. Syncytium formation induced by BLV-infected cells was effectively suppressed by the liposomes containing the gene for DT-A under the control of BLV-LTR. Conversely, liposomes containing the gene for DT-A without a promoter showed no such effect. DT-A gene-containing liposomes with BLV-LTR did not affect formation of syncytium induced by bovine immunodeficiency virus. These observations indicate that BLV-infected cells were readily targeted on the level of gene expression. This strategy could be applied to the treatment of BLV-induced B-cell proliferation of cattle, and further to other viral/neoplastic diseases where specific gene expression is exerted.

Animals↗
PubMed1993

Studies on hemolytic action of a hemolysin produced by Vibrio mimicus.

Some properties and mechanism of action of a hemolysin (VMH) produced by an enteropathogenic Vibrio mimicus strain was examined. VMH was heat-labile and inhibited by addition of divalent cations, including Ca2+, Mg2+ and Mn2+. The hemolysis by VMH was inhibited by incubating with gangliosides, suggesting that the ganglioside was the binding site on the erythrocyte membrane for VMH. Existence of a galactose moiety on reducing end of the ganglioside molecule and a sialic acid on the galactose moiety was suggested to be important for the binding of VMH molecule. Colloid osmotic manner of the hemolysis by VMH was demonstrated.

Animals↗
PubMed1993

Expression of anticardiolipin cofactor, human beta 2-glycoprotein I, by a recombinant baculovirus/insect cell system.

A full-length cDNA coding a human beta 2-glycoprotein I (beta 2-GPI) was introduced into the baculovirus genome to construct a recombinant baculovirus. Spodoptera frugiperda (Sf9) cells were infected with the recombinant baculovirus. A protein (mol. wt 43,000) reactive with anti-beta 2-GPI antisera was produced in the insect cells and secreted into the culture medium. The recombinant beta 2-GPI was purified from the culture supernatant by sequential cardiolipin (CL)-affinity column chromatography and gel filtration. The N-terminal amino acid sequence of the protein was identical to that of the native beta 2-GPI purified from human sera, and a putative signal peptide was cleaved from the secreted form of the recombinant protein. The purified recombinant protein had a cofactor activity which enhances CL binding of anticardiolipin antibodies (aCL) in systemic lupus erythematosus (SLE) patients, as well as the native beta 2-GPI. Thus, the beta 2-GPI expressed in insect cells is an immunologically active cofactor.

Amino Acid Sequence↗
PubMed1993

Three-dimensional structure of human insulin-like growth factor-I (IGF-I) determined by 1H-NMR and distance geometry.

The three-dimensional structure of human insulin-like growth factor-I has been determined through a combination of NMR measurements and distance geometry calculations. A total of 320 interatomic distance constraints, including 12 related to the disulfide bridges, were used in these calculations. The resulting structure is characterized by the presence of three helical rods corresponding to the sequence regions, Ala8-Cys18, Gly42-Cys48 and Leu54-Cys61. Furthermore, a turn structure and an extended structure exist in the Gly19-Gly22 and Phe23-Asn26 regions, respectively. Neglecting the N- and C-termini, with their expectedly high degree of mobility as well as a fluctuating C-domain, the r.m.s.d. value is 1.9 A for backbone atoms. Those of the three alpha-helical regions are 1.0, 0.9 and 0.8 A, respectively, 1.8 A being that for the total backbone atoms participating in the formation of these three helices, showing the good convergence of their spatial arrangements. The overall structure obtained here shows that the human IGF-I molecule folds into a spatial structure very similar to that of insulin in an aqueous solution.

Amides↗
PubMed1993

Intractable hiccups and sleep apnea syndrome in multiple sclerosis: report of two cases.

Two cases of multiple sclerosis associated with intractable hiccups (IH) and sleep apnea syndrome (SAS) are reported. Lesions were detected in the tegmentum of the medulla oblongata by magnetic resonance imaging. In one case, high dose methylprednisolone was remarkably effective for the IH. For the SAS, amitriptyline was effective in one case. The IH and SAS are thought to be important symptoms when a lesion occurs in the tegmentum of the medulla oblongata, including the paramedian and lateral reticular formations. If IH appears in conjunction with a lesion in the tegmentum of the medulla oblongata, one must be vigilant for the development of SAS.

Amitriptyline↗
PubMed1993

Papillo-choledochectomy in the operative management of mucosal neoplasms of the periampullary region.

Two patients with mucosal cancer of the periampullary region were treated with papillo-choledochectomy, which entails removal of the papilla of Vater and the whole length of the common bile duct. The neoplasm is dissected out through the plane between the duodenal circular and longitudinal muscles, deep to the sphincter of Oddi and the fibromuscular layer of the bile duct. Pathological examination showed that cancer was confined to the mucosal layer without stromal invasion, and that the operation achieved radical cure. For mucosal cancer, papillo-choledochectomy is an alternative to pancreatoduodenectomy, provided that repeated frozen-section studies confirm the completeness of excision.

Adenocarcinoma↗
PubMed1993

Neuron-specific enolase and glial fibrillary acidic protein in vitamin-A-induced mouse myeloschisis: an immunohistochemical study.

In an effort to establish the appropriate timing of myeloschisis repair, changes in the exposed neural tissue were studied during fetal development. Neuron-specific enolase (NSE) and glial fibrillary acidic protein (GFAP) were examined immunohistochemically in mice with vitamin-A-induced myeloschisis. As in the normally developing lumbosacral spinal cord, NSE was already expressed in the cytoplasm of neurons in the basal plate of the neural plaque in 16-day-old embryos. GFAP became positive at day 17 both in normal embryos and at the outer border of the plaques in dysraphic embryos. Expression of both NSE and GFAP in normal controls was unchanged in intensity and localization during later fetal development. In contrast, the expression of GFAP increased during later development in the neural plaque of dysraphic animals and suggests a progressive gliosis of tissue with the passage of time. The expression of NSE in the plaque did not change during this time. These results suggest that the neural plaque retains intact neurons in the face of progressive gliosis. Moreover, the results suggest that repair of the myeloschisis should start before irreversible changes are established by progressive gliosis.

Animals↗