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Biomedical subjects

T Yasuda

Publications and source records attributed to T Yasuda.

At least 487 records · Page 27Linked to original sources
PubMed1994

Antithrombotic effects and bleeding time prolongation with synthetic platelet GPIIb/IIIa inhibitors in animal models of platelet-mediated thrombosis.

Cyclic Arg-Gly-Asp (RGD) containing synthetic peptides such as L-cysteine, N-(mercaptoacetyl)-D-tyrosyl-L-arginylglycyl-L-alpha-aspartyl- cyclic (1-->5)-sulfide, 5-oxide (G4120) and acetyl-L-cysteinyl-L-asparaginyl-L-propyl-L-arginyl-glycyl-L-alpha- aspartyl-[0-methyltyrosyl]-L-arginyl-L-cysteinamide, cyclic 1-->9-sulfide (TP9201) bind with high affinity to the platelet GPIIb/IIIa receptor. The relationship between antithrombotic effect, ex vivo platelet aggregation and bleeding time prolongation with both agents was studied in hamsters with a standardized femoral vein endothelial cell injury predisposing to platelet-rich mural thrombosis, and in dogs with a carotid arterial eversion graft inserted in the femoral artery. Intravenous administration of G4120 in hamsters inhibited in vivo thrombus formation with a 50% inhibitory bolus dose (ID50) of approximately 20 micrograms/kg, ex vivo ADP-induced platelet aggregation with ID50 of 10 micrograms/kg, and bolus injection of 1 mg/kg prolonged the bleeding time from 38 +/- 9 to 1,100 +/- 330 s. Administration of TP9201 in hamsters inhibited in vivo thrombus formation with ID50 of 30 micrograms/kg, ex vivo platelet aggregation with an ID50 of 50 micrograms/kg and bolus injection of 1 mg/kg did not prolong the template bleeding time. In the dog eversion graft model, infusion of 100 micrograms/kg of G4120 over 60 min did not fully inhibit platelet-mediated thrombotic occlusion but was associated with inhibition of ADP-induced ex vivo platelet aggregation and with prolongation of the template bleeding time from 1.3 +/- 0.4 to 12 +/- 2 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1994

Prognostic value of cerebrospinal fluid neuron-specific enolase and S-100b protein in Guillain-Barré syndrome.

We measured the cerebrospinal fluid (CSF) concentrations of neuron-specific enolase (NSE) and S-100b protein (S-100b) using enzyme immunoassay methods, in 24 patients with Guillain-Barré syndrome and 46 controls, and examined their prognostic values. Sixteen of 24 patients showed elevated levels (> the mean + 2SD levels of controls) of NSE, S-100b, or both, and in those with higher NSE or S-100b levels there was a rather longer duration of disease, whereas 8 patients with the normal levels showed an early recovery. Further, NSE or S-100b levels were significantly correlated with months to recovery. Thus, NSE and S-100b in CSF may be useful markers for predicting the outcome of Guillain-Barré syndrome.

Adolescent↗
PubMed1994

[Antibacterial activity of tosufloxacin against fresh clinical isolates].

The antibacterial activity of tosufloxacin (TFLX) was compared with those of other new quinolones (ofloxacin, ciprofloxacin, sparfloxacin and fleroxacin) against clinical isolates. These isolates had been collected from May to June 1993 (22 species, 260 strains) and from June to July 1992 (Staphylococcus aureus and Pseudomonas aeruginosa, 87 strains) in Toyama municipal hospital. TFLX showed the most potent activities against methicillin-susceptible S. aureus, methicillin-susceptible Staphylococcus epidermidis, methicillin-resistant S. epidermidis, Enterococcus faecalis and Escherichia coli in 1993, at MIC50 levels. The MIC50's of TFLX for these species ranged from 0.025 to 0.39 microgram/ml. TFLX showed potent activities against Klebsiella pneumoniae and P. aeruginosa, and the MIC50's of TFLX were 0.05 and 0.39 microgram/ml, respectively. However, new quinolone resistant strains (MIC > or = 6.25 micrograms/ml) were found among some species. Especially, the number of methicillin-resistant S. aureus (MRSA) strains resistant to new quinolone exceeded 60% of all the S. aureus isolates in 1993. More MRSA strains resistant to new quinolones were isolated in 1993 than in 1992, and similar result was observed for P. aeruginosa. The coagulase typing was done, and all MRSA strains of resistant to new quinolones produced coagulase type II.

Anti-Infective Agents↗
PubMed1994

[Pharmacokinetics and changes of reduced folate levels in tumor after administration of cisplatin].

Cisplatin acts as a biochemical modulator of 5-FU to increase the intracellular concentration of reduced folates. To determine the optimum schedule for administering cisplatin as a 5-FU modulator, we analyzed pharmacokinetics of platinum and changes of reduced folate levels in the tumor following administration of cisplatin in Yoshida sarcoma-bearing rats. Clinical kinetics of cisplatin was also investigated. The reduced folate level in the tumor was temporarily increased 2-1.6 fold of the control level 1-2 hours after the rapid injection of cisplatin (4 mg/kg). The folate level 2 hours after the rapid injection of cisplatin increased dose-dependently within the dose of 1mg/kg and reached to the plateau with the doses of 1, 2, 4, 8 mg/kg, although the platinum concentration in plasma and tumor increased linearly correlated with the dose of cisplatin. These findings suggest the modulatory effect through rapid injection of cisplatin is transiently exerted only in the early phase, and not dose-dependently but limitatively with the dose of 1 mg/kg or more. Therefore, repeated administration with low dose or continuous infusion of cisplatin simultaneous with 5-FU derivatives is desirable for combination chemotherapy. Clinically, the minimum effective dose of cisplatin as a modulator was thought to be 10-20 mg/body judging from experimental as well as clinical kinetic study of cisplatin.

Animals↗
PubMed1994

[Relationship between thermal threshold and population of peripheral nerve fibers].

The relationship skin thermal threshold (TT) and density of both myelinated and unmyelinated fibers were investigated in 12 patients with various peripheral nerve diseases including Crow-Fukase syndrome, carcinomatous neuropathy and Charcot-Marie-Tooth disease. The TT was measured at a site above the medial tibial condyle using a thermal threshold tester. The TT was defined as the threshold at which a slight rise or fall in temperature could be detected. The size of the skin stimulation area was 13.5 cm2, the temperature change rate was 1 degrees C/sec, and the basal temperature was set at 34 degrees C. A sural nerve biopsy was performed and an image processor (IBAS) was used to measure the nerve fiber density. The TT in the patients with peripheral nerve disease was found to be elevated when compared with that of the 74 healthy controls (mean age of 38.1 +/- 13.3 years). Elevation of the TT has an intimate relation to damage of the small myelinated nerve fibers. In conclusion, unmyelinated fibers may play a relatively minor role in conveying thermal sensation.

Adult↗
PubMed1994

[Common carotid artery thrombosis--clinical and radiological evaluation].

Common carotid artery thrombosis (CCAT) is not common. We studied 4 patients with CCAT to clarify the clinical and radiological features of this disorder. Case 1 had only episodes of TIA. Case 2 was diagnosed by chance as having CCAT at the time of admission due to cerebellar infarction. On the contrary, Cases 3 and 4 were admitted because of disturbance of consciousness and hemiparesis. Case 4 died soon after his stroke because of complications. We evaluated cases 1, 2 and 3 using head CT, head MRI, neck MRI, MR angiography, SPECT and cerebral angiography. Case 4, who was evaluated with head CT and cerebral angiography, was autopsied to confirm the occlusion of the common carotid artery. The clinical severity of CCAT varies from asymptomatic to severe, because each differs in the time taken for complete occlusion of the common carotid artery; the development of collateral circulation; and hemodynamics of the brain. As for the collaterals their contribution is variable; for example, the thyrocervical and other arteries function as the bypass. We can diagnose CCAT easily and noninvasively using MR angiography and neck MRI based on disappearance of the flow void in the common carotid artery or internal carotid artery. On physical examination, it is important to detect faded pulsation of the superficial temporal artery that is ipsilateral to the occluded common carotid artery.

Aged↗
PubMed1994

[Magnetic resonance imaging of spinal cord lesions in 22 multiple sclerosis patients].

We reviewed MRI findings in 22 patients (37 cases) with clinically diagnosed multiple sclerosis (MS) with spinal cord lesions. The spinal cord lesions were detected in 17 (46%) of these 37 cases on MRI. The cervical cord lesions were more detectable than other spinal cord lesions. At the thoracic level, the upper lesions were more detectable than the lower ones. In this study, no correlation was found between the disease duration, the rate of functional disturbance and the detectable rate of spinal cord lesions. The characteristic findings of the lesions were swelling and the enhancement effect of Gd-DTPA in the patient group with a disease duration of less than three years, and atrophic change in the patient group with a disease duration of greater than seven years. The period of the enhancement effect of Gd-DTPA varied in each case, and it may reflect the clinical course. Syrinx-like lesions were found in four cases. In one of them, atrophic change was found in the same region six months after the follow up study. Although the precise reason for the syrinx-like lesion was unclear, a relationship between syrinx-like lesion and atrophy of the spinal cord was suggested. The MRI findings of the spinal cord lesions in MS varied in each case and in each stage of the disease.

Adolescent↗
PubMed1993

Two distinct secretory ribonucleases from human cerebrum: purification, characterization and relationships to other ribonucleases.

Two RNAases from human cerebrum were purified to an electrophoretically homogeneous state and their molecular masses were 22.0 kDa (tentatively called RNAase HB-1) and 19.0 kDa (RNAase HB-2). Analyses of the amino acid compositions, N-terminal amino acid sequences and catalytic properties of these enzymes provided strong evidence that they were strictly related to the secretory (sec) RNAases, such as the pancreatic enzyme, very similar immunologically to urinary sec RNAase, but clearly distinguishable from urinary non-secretory (nonsec) RNAase. There were several differences between HB-1 and HB-2, namely their immunological reactivities with specific antibodies, heat-stabilities, attached carbohydrate moieties and molecular masses. In particular, HB-2 appeared to be nonglycosylated, in view of its lack of affinity for several conjugated lectins, the absence of hexosamine and no change in electrophoretic mobility before and after peptide:N-glycosidase F digestion, whereas HB-1 and human sec RNAases purified from kidney, pancreas and urine all appeared to be glycosylated, as they moved to the same position as HB-2 when electrophoresed after glycosidase digestion. An antibody against urinary sec RNAase inhibited 75% and 20% of the total activity of the crude cerebral extract against RNA at pH 8.0 and 6.0 respectively, whereas an antibody against urinary nonsec RNAase had no such inhibitory effect. These findings suggest that yet another type(s) of cerebral RNAase, which is unable to cross-react immunologically with sec and nonsec RNAases, may exist. Two RNAases corresponding to HB-1 and HB-2 were identified in fresh cerebrospinal fluid.

Amino Acid Sequence↗
PubMed1993

Kappa marker typing with high-performance liquid chromatography: identification of kappa marker specific tryptic peptide from the kappa light chain of immunoglobulin G.

Human serum immunoglobulin G was separated into its heavy and light chains by sodium dodecyl sulfate polyacrylamide gel electrophoresis and transferred electrophoretically to a polyvinylidenedifluoride membrane. Peptide fragments liberated from the light chain by in situ digestion with trypsin were then analyzed by reversed-phase high-performance liquid chromatography (HPLC). On comparing the HPLC patterns of these fragments derived from three major kappa marker (Km) types, two distinct peaks specific for the Km types were detected. Sequencing of the two specific peak peptides confirmed that they were identical to a stretch comprising residues 191-207 of the immunoglobulin kappa light chain, which contains valine/leucine allotypic variation at position 191.

Amino Acid Sequence↗
PubMed1993

Specific expression of the pancreatic-secretory-trypsin-inhibitor (PSTI) gene in hepatocellular carcinoma.

Twenty hepatocellular carcinomas (HCC) were analyzed by Northern blotting to test the expression of pancreatic secretory trypsin inhibitor (PSTI). This gene was expressed in all HCCs, but not in other tumors, including mammary, thyroid, pulmonary and ovarian cancers. Some gastric and colonic cancers weakly expressed PSTI. Among cell lines examined in a similar manner, PSTI was expressed in all of 4 derived from hepatoma. On the other hand, among 15 cell lines derived from cancers other than hepatoma, only 3, derived from pancreatic, colonic and gastric cancers, weakly expressed PSTI. A CAT assay using a deletion set of the 5' region from the cloned PSTI gene has shown that in hepatoma cell lines, the expression of this gene is dependent on the presence of 2 regulatory regions that include an IL-6 responsive elements and an AP-I-binding site. However, in non-hepatoma cell lines, the 2 regulatory regions are not necessary for expression. The blood level of PSTI in 27 patients with HCC was significantly increased, and it was positively correlated with tumor size, suggesting that specific expression of PSTI in HCC causes this effect and that elevated blood level of PSTI without inflammation indicates the presence of HCC.

Adult↗
PubMed1993

Human seminal deoxyribonuclease I (DNase I): purification, enzymological and immunological characterization and origin.

Deoxyribonuclease I (DNase I) was purified from the semen of a 38-year-old male and then characterized. The catalytic properties of the purified enzyme closely resembled those of DNase I purified from the urine of this individual and the following other similarities were observed: molecular masses, iodoacetic acid inactivation kinetics, desialylated isoenzyme patterns. However, the behavior of the purified enzymes determined on several different lectin-affinity chromatography columns differed, which suggests that organ-specific glycosylation of DNase I occurs. Multiple forms of the purified seminal DNase I were demonstrated, each of which had a different pI value separated by isoelectric focusing, which is compatible with the reported existence of genetic polymorphism of seminal DNase I (Sawazaki et al., Forensic Sci Int 1992;57:39-44). Furthermore, enzymological and immunological comparisons of purified seminal and urinary and partially purified prostatic DNases I indicated that the prostate may be one of seminal enzyme source tissues.

Adult↗
PubMed1993

Identification of the IL-6-responsive element in an acute-phase-responsive human pancreatic secretory trypsin inhibitor-encoding gene.

Pancreatic secretory trypsin inhibitor (PSTI) has been suggested to be an acute-phase reactant in humans and to be induced by inflammatory cytokines such as the interleukins IL-1 and IL-6. We report that PSTI is synthesized in hepatoma cells and that the gene expression is augmented by IL-6. The start points (tsp) for basal and augmented transcription are exactly the same as the tsp in normal pancreas. Analysis of the PSTI gene revealed that a 40-bp DNA fragment located between kb -3.84 and -3.80 carries the element responsible for both transcriptional activity and IL-6-induced gene expression. This 40-bp fragment contains TTGNNGNAATG, the consensus sequence for the NF-IL6-binding site, which is also known as the IL-6-responsive element that is conserved among various acute-phase genes. The basal activity was augmented by another sequence that lies between kb -4.0 and -3.9.

Acute-Phase Proteins↗
PubMed1993

Identification and characterization of a nuclear scaffold protein that binds the matrix attachment region DNA.

The association of nuclear DNA with the nuclear matrix (scaffold) is mediated by defined segments of DNA called matrix association region (MAR). By using a plasmid harboring a portion of the Ig kappa gene within which MAR had been located, we searched for proteins recognizing MAR in the nuclear scaffold components electrophoretically separated and blotted onto a membrane. In the presence of nonspecific competitor DNA, the labeled plasmid selectively bound to a protein with apparent molecular weight of 120,000 (designated SP120). The protein was purified directly from SDS-polyacrylamide gels and renatured by a guanidine hydrochloride procedure. The DNA region in the plasmid responsible for the binding to the solubilized SP120 coincided with the 365-base pair HindIII-HinfI fragment that had been identified as MAR. In solution, SP120 exhibited a cooperative mode of interaction with the end-labeled MAR fragment. Measurement of relative affinities of MAR subfragments to SP120 showed that the whole region is required for efficient binding. This is consistent with the minimal length for MAR estimated thus far by in situ mapping experiments. The MAR derived from another gene, fushitarazu, also bound specifically to SP120. Immunostaining of whole cells and isolated nuclei with a monoclonal antibody raised against SP120 indicated that the protein is localized in a nuclear skeletal structure. These results suggest the involvement of SP120 in the MAR-mediated anchorage of nuclear DNA to the nuclear scaffold.

Animals↗
PubMed1993

Salivary deoxyribonuclease I polymorphism separated by polyacrylamide gel-isoelectric focusing and detected by the dried agarose film overlay method.

Isoelectric focusing of whole saliva samples on polyacrylamide gels (pH 3.5-5), followed by dried agarose film overlay detection, was employed to determine the type of salivary deoxyribonuclease I (DNase I). Since this detection method had not only a high sensitivity, but also a high band resolution, it was possible to determine DNase I types from saliva samples of 2-5 microL. Pretreatment of saliva samples with neuraminidase simplified the isozyme pattern and enhanced the sensitivity. The DNase I types in all 30 saliva samples showed a good correlation with the types found in the corresponding blood, semen, and urine samples. This preliminary trial indicates that DNase I typing from saliva samples is a new and promising method for individualization of casework samples in the field of forensic biology.

Deoxyribonuclease I↗