Biomedical subjects

M Yasuda

Publications and source records attributed to M Yasuda.

At least 181 records · Page 10Linked to original sources

PubMed1998

A carbon-centered radical as a reaction species in the DNA strand-breakage by D-glucosamine.

Electron spin resonance(ESR) studies using 5,5-dimethyl-1-pyrroline N-oxide (DMPO) and sodium 3,5-dibromo-4-nitrosobenzensulfonate (DBNBS) as a spin-trapping agent revealed the formation of both hydroxyl and carbon-centered radical-derived spin adducts in Cu2+-containing 50 mM Tris-HCl buffered solutions (pH 7.1) of D-glucosamine, D-mannosamine, and D-galactosamine, which were previously shown to have the ability to break the single-strand of plasmid pBR322 DNA in a nucleotide sequence-specific manner. HCl-free D-glucosamine has higher DNA breaking activity, and this activity is promoted more by the presence of Cu2+ than the original D-glucosamine hydrochloride, exhibits stronger radical signals in the ESR spectrum. It is suggested that D-glucosamine is unstable around neutral pH, being converted into certain intermediate(s) such as a dihydropyrazine compound, which generate(s) carbon-centered radicals, and that, besides the hydroxyl radical, the intermediate(s) is/are responsible for DNA strand breakage.

Benzenesulfonates↗

PubMed1998

Relationship between MLR blocking antibodies and the outcome of the third pregnancy in patients with two consecutive spontaneous abortions.

To determine the relationship between mixed lymphocyte culture reaction (MLR) blocking antibodies (BAbs), immunological humoral factors, which generated in pregnant women and the outcome of pregnancy, the natural outcome of the third pregnancy in fifty-five patients with primary twice consecutive abortion was evaluated, and MLR-BAbs in sera were examined during their third pregnancy. The third pregnancy in 39 of 55 patients (70.9%) continued successfully, and remaining 16 patients (29.1%) experienced repeated abortion at the first trimester. Out of these 55 patients, MLR-BAbs were examined in 27 (17 with successful outcome and 10 with repeated abortion). The positive rate of MLR-BAbs was 82.4% in patients with successful outcome (15 of 17 cases), and that in patients with repeated abortion was 10% (one of 10 cases). The positive rate of MLR-BAbs was significantly higher in the successful pregnancy group compared with that in the repeated abortion group (p < 0.001). The blocking effect on MLR significantly increased along with the prenatal course in patients with successful outcome. Thus, MLR-BAbs are strongly associated with the outcome of pregnancy in patients with primary twice consecutive spontaneous abortions.

Abortion, Habitual↗

PubMed1998

Anti-cardiolipin antibody and anti-cardiolipin beta-2-glycoprotein I antibody in patients with recurrent fetal miscarriage.

To elucidate the association between anticardiolipin antibody (aCL-Ab) or anti-cardiolipin beta-2-glycoprotein I-antibody (aCL-beta-2-GP I-Ab) and recurrent fetal miscarriage, the positive rates of aCL-Ab were assessed in 667 patients with recurrent fetal miscarriages and those of aCL-beta-2-GP I-Ab were assessed in 208 patients. The rates were then compared with the control group. The positive rate of aCL-Ab in the patients group (17.4%) was significantly higher than that in the control group (4.0%). The rate of aCL-Ab was especially high in patients who had experienced two or more fetal miscarriages including at least one or more intrauterine fetal deaths during the second or third trimester (41.3%). The positive rate of aCL-beta-2-GP I-Ab in patients with recurrent fetal miscarriage (3/208 cases, 1.4%) was not significantly different from the control group (0/100 cases, 0%). However, the rate of aCL-beta-2-GP I-Ab was significantly higher in patients who had experienced two or more fetal miscarriages including at least one or more intrauterine fetal deaths during the second or third trimester (8.3%) compared with the control group. In conclusion, the implication of aCL-Ab in the genesis of recurrent fetal miscarriage was confirmed. It was suggested that aCL-beta-2-GP I-Ab was associated with the generation of intrauterine fetal death, although it had little association with the genesis of recurrent fetal miscarriage during the first trimester.

Abortion, Habitual↗

PubMed1998

Correlation between NO-induced ATP depletion and cytotoxicity in PC12 cells.

To ascertain whether NO-elicited cell death is mediated by decreased intracellular ATP, the effect of sodium nitroprusside (SNP), a NO-generator, on ATP content in PC12 cells was examined. After treatment with SNP, the ATP content in PC12 cells was found to decline in a time- and concentration-dependent manner. The decline of ATP content in PC12 cells caused by SNP was found to occur before the appearance of cytotoxicity estimated by MTT staining. In addition, the ATP content of neuronally differentiated PC12 cells, which has been shown to have a higher resistance to SNP than the undifferentiated cells (Nakamura et al., 1997), was less affected by SNP treatment than the undifferentiated cells. These findings suggest that reduction of intracellular ATP content may be one of the mechanisms responsible for the NO toxicity in PC12 cells.

Adenosine Triphosphate↗

PubMed1998

NO depletes cellular ATP contents via inactivation of glyceraldehyde-3-phosphate dehydrogenase in PC12 cells.

Recently, we demonstrated that nitric oxide (NO) reduces ATP generation via oxidative phosphorylation coupled with the mitochondrial respiratory chain in PC12 cells resulting in induction of apoptotic cell death. To further study the correlation between NO-induced ATP depletion and neuronal death, we examined the effect of NO on glycolytic ATP generation in PC12 cells, a neuronal model. When the oxidative phosphorylation was maximally suppressed by DNP and oligomycin, which are inhibitors of the mitochondrial respiratory chain, the cellular ATP contents were reduced by sodium nitroprusside (SNP). In addition, the cellular ATP contents were further decreased along with a decrease in the activity of glyceraldehyde-3-phosphate dehydrogenase (G3PDH), a key enzyme in the glycolytic pathway. Benzamide, an inhibitor of poly (ADP-ribose) synthetase, could protect the depletion of NAD but had no effect on the depletion of ATP in PC12 cells induced by NO. These results suggest that the depletion of ATP in PC12 cells caused via the inhibition of G3PDH by NO is one of the mechanisms responsible for NO neurotoxicity.

Adenosine Triphosphate↗

PubMed1998

A case of the scalenus anterior muscle lying behind the fifth cervical nerve root.

Muscle slip composition and innervation was minutely examined in the case of the scalenus anterior muscle lying behind the 5th cervical nerve root. This minor change of topography deeply involved the muscle-nerve relationships of the entire muscle. Critical observations were as follows: (1) lower and unusual origins of the muscle; (2) irregular innervation with regard to the nerve elements and their approach to the muscle. This evidence suggested that abnormal migration, splitting and fusion of the muscle anlage had occurred during the development of the variant.

Aged↗

PubMed1998

[Anticancer susceptibility test method using general-purpose dissolved oxygen meter].

Drug susceptibility of cell can be rapidly measured by continuously monitoring its metabolic changes. We focused on respiration volume as a signal of metabolic change, and developed a new dissolved oxygen measuring system which can detect respiration volume of cells. The main feature of the system is the use of a new type bare oxygen electrode which can easily detect the changing rate of dissolved oxygen concentration. In this study, single type electrode was used to evaluate this rapid anticancer drug susceptibility test. The result obtained was almost equivalent to that with MTT method, which is a conventional method for susceptibility test of HL-60 to various kinds of anticancer drugs. We have also developed multi-type electrode plate with oxygen electrodes embedded in the bottom of 96-well plate, with which clinical evaluation of this method can be easily made.

Antineoplastic Agents↗

PubMed1998

Enhancement of tissue factor following ischemic-reperfusion injury in rats.

To evaluate the involvement of tissue factor (TF) in blood coagulation reflecting injury of the blood vessels induced by reperfusion following ischemic treatment in rat abdominal blood vessels in vivo, both TF expression and prothrombin time (PTT), which is used as a marker of coagulation, were measured after ischemic-reperfusion treatment. TF expression was significantly increased at 0 and 5 min after reperfusion following a 30 min period of vessel ligation, while the PTT was significantly shortened at 5 and 10 min. On the other hand, the change of TF expression and PTT were not detected in the animals ligated vessel for 15 min. These results suggest that TF plays an important role in the injury after reperfusion following ischemia.

Abdomen↗

PubMed1998

Can the liver with Gilbert's syndrome be used as graft of living-related liver transplantation?

Gilbert's syndrome is the common cause of non hemolytic unconjugated hyperbilirubinemia with a prevalance of 3-7%. Gilbert's syndrome may introduce a selection of potential liver donors from brain death patients. We present a case of living-related liver transplantation (LRLT) from a donor with Gilbert's syndrome. A 22-year-old woman had been diagnosed as having liver cirrhosis at the age of 5. She underwent liver transplantation with the donor's left lobe as the graft. The donor, who was the father of the patient, had been diagnosed with Gilbert's syndrome. Although the recipient was well until 11 months after surgery, she died of subacute fulminant hepatitis 16 months after surgery. However, it was clear that the liver with Gilbert's syndrome could be used as a graft of living-related liver transplantation for adult recipients.

Adult↗

PubMed1998

[Intraarterial chemotherapy via reservoir system for far-advanced bladder and prostate cancer].

A clinical study was performed on the efficacy of intraarterial chemotherapy using reservoir system for far-advanced urological malignancy. The reservoir system was indwelled in the femoral subcutaneous layer using Seldinger's method. Fifteen cases with inoperable complicated advanced bladder cancer and ten cases with postoperative local recurrent bladder cancer received intraarterial chemotherapy using the reservoir system. Then, 23 cases with local relapsed prostate cancer and two cases with endocrine-resistant prostate cancer received chemotherapy. The administered anti-cancerous agents were methotrexate, cis-platinum and adriamycin, and 5-FU or carboplatin were administered as maintenance therapy. The mean courses of chemotherapy were six for bladder cancer and four for prostate cancer. During stabilization of the local lesion, no distant deterioration was recognized. Overall clinical efficacy was as follows: PR:18 cases and NC:7 cases for bladder cancer; then, PR:11 cases and 14 cases for prostate cancer. The median duration of stabilization was as follows: 23 months for bladder cancer and 12 months for prostate cancer. Complications were fewer than with systemic chemotherapy.

Adenocarcinoma↗

PubMed1998

[A case of congenital mesoblastic nephroma in adulthood].

A 20-year-old man was referred to our hospital with a complaint of asymptomatic macrohematuria. A diagnosis of a right renal tumor was made after several radiographic examinations and right radical nephrectomy was performed. Histopathologically the tumor was a congenital mesoblastic nephroma. Congenital mesoblastic nephroma is a relatively rare renal tumor predominantly of childhood. Occurrence in adults is exceedingly rare and 18 cases have been reported to date.

Adult↗

PubMed1998

[Dorso-ventral patterning of the vertebrate limb and dermatoglyphs with special reference to the pad pattern of mice].

The proximo-distal (P-D), antero-posterior (A-P) and dorso-ventral (D-V) axes are important for normal limb development in vertebrates. It has been reported that D-V axis is decided by Wnt-7a, Lmx-1 and Engrailed-1 (En-1) which are expressed in the limb bud along D-V axis. These factors are thought to be required for formation of the apical ectodermal ridge (AER) which is necessary for outgrowth of the limb. The results from spontaneous mutant mice meromelia (mem), which exhibits double-dorsality of the distal limb, suggested that other factors, not only En-1 and Wnt-7a are required for decision of AER, and mem was probed to be novel gene regulating En-1 and Wnt-7a directly or indirectly. The dorsalized ventral structures in meromelia were found by observation of the pad pattern. Pad pattern is always constant in normal mice, and each pad indicates particular part of the limb. So pad pattern is useful to detect and describe anomalies even in the limbs without skeletal defects. The process of pad development is associated with the limb patterning, and abnormal pad pattern may indicate pathogenesis of abnormal limb development. The mouse pad pattern is usable as the model for human dermatoglyphs, and it is also important to investigate mechanisms of human diseases.

Animals↗

PubMed1997

Simultaneous determination of creatinine, creatine, and guanidinoacetic acid in human serum and urine using liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

A rapid and direct method for simultaneous determination of creatinine, creatine, and guanidinoacetic acid in biological samples has been developed by using column liquid chromatography-mass spectrometry (LC/APCI-MS). The determinations of creatinine, creatine, and guanidinoacetic acid in the samples of human urine and serum were carried out by scanning the [M + H]+ ions of each compound. The recoveries of authentic compounds were 93.87 +/- 6.00% (n = 5) for creatinine, 94.80 +/- 8.93% (n = 5) for creatine, and 90. 92 +/- 7.96% (n = 5) for guanidinoacetic acid after ion-exchange resin treatment. The content of creatinine in human urine and serum was also measured by the Jaffé method, a common method of determination of creatinine currently used in hospitals. The contents of creatinine, creatine, and guanidinoacetic acid obtained using LC/APCI-MS coincided well with those reported in previous papers.

Atmospheric Pressure↗

PubMed1997

Fyn-kinase as a determinant of ethanol sensitivity: relation to NMDA-receptor function.

Animals vary in their sensitivity to ethanol, a trait at least partly determined by genetic factors. In order to identify possible responsible genes, mice lacking Fyn, a non-receptor type tyrosine kinase, were investigated. These mice were hypersensitive to the hypnotic effect of ethanol. The administration of ethanol enhanced tyrosine phosphorylation of the N-methyl-D-aspartate receptor (NMDAR) in the hippocampus of control mice but not in Fyn-deficient mice. An acute tolerance to ethanol inhibition of NMDAR-mediated excitatory postsynaptic potentials in hippocampal slices developed in control mice but not in Fyn-deficient mice. These results indicate that Fyn affects behavioral, biochemical, and physiological responses to ethanol.

Animals↗

PubMed1997

Mutations in the gyrA and parC genes associated with fluoroquinolone resistance in clinical isolates of Citrobacter freundii.

We determined partial sequences of the gyrA and parC genes of Citrobacter freundii type strain, and then examined 38 C. freundii clinical strains isolated from patients with urinary tract infections for the association of alterations in GyrA and ParC with susceptibility to fluoroquinolones. Our results suggest that in C. freundii DNA gyrase may be a primary target of quinolones, that an amino acid change at Thr-83 or Asp-87 in GyrA is sufficient to decrease susceptibility to fluoroquinolones, and that accumulation of changes in GyrA with the simultaneous presence of an alteration at Ser-80 or Glu-84 in ParC may be associated with the development of high-level fluoroquinolone resistance in C. freundii clinical isolates.

Amino Acid Sequence↗

PubMed1997

A novel missense mutation in the presenilin-1 gene in a familial Alzheimer's disease pedigree with abundant amyloid angiopathy.

A number of missense mutations associated with early-onset familial Alzheimer's disease have been reported in the presenilin-1 gene. The mutations were demonstrated to cluster in specific regions of the the protein. We report here a novel missense mutation at the C-terminus of the third transmembrane domain in the presenilin-1 protein in a family of Japanese origin with early-onset Alzheimer's disease. This mutation is located at a site that is different from the sites at which mutations are known to cluster. Although the clinical phenotype is similar to those of pedigrees associated with other presenilin-1 mutations, postmortem examination of this pedigree revealed heavy amyloid deposits in the walls of small meningeal arteries as well as around small vessels within the brain parenchyma. These results indicate that a mutation at the C-terminus of the third transmembrane domain in the presenilin-1, which is a novel site for mutations, may play a key role in Alzheimer's pathogenesis.

Adult↗

PubMed1997

Reduction of radiation-induced xerostomia in nasopharyngeal carcinoma using CT simulation with laser patient marking and three-field irradiation technique.

PURPOSE: Tumor control and reduction of postirradiation xerostomia in patients with nasopharyngeal carcinoma (NPC) using the three-field irradiation technique based on the CT-based simulation with laser patient marking was investigated. METHODS AND MATERIALS: Seventy-eight patients with NPC were consecutively treated between 1983 and 1993. In 33 patients treated before 1987, target volume was determined using a conventional x-ray simulator with a reference of CT images, and the primary site was treated by the conventional parallel-opposed two-field technique (Group I). In 45 patients treated from 1987, target volume was determined using a CT simulator slice by slice, the treatment field was projected onto the patient's skin by a laser beam projector mounted on a C-arm, and the primary site was irradiated by a three-fields (anterior and bilateral) technique (Group II). In Group II, the shape of each field was determined using a beam's eye view to reduce the dose to the bilateral parotid glands. The three-field technique reduced the dose to the superficial lobe of parotid gland to about two-thirds of the dose given by the two-field technique. Radiation-induced xerostomia was evaluated by clinical symptoms and radioisotope sialography. RESULTS: The 5-year survival rate and disease-free survival rate were 46.6 and 31.2% in Group I, and 46.8 and 46.5% in Group II. A large variation in the volume of parotid glands were demonstrated, ranging from 9 cm3 to 61 cm3 among patients treated with CT simulation. Forty percent of the patients in Group II showed no or mild xerostomia, whereas all of the patients in Group I showed moderate to severe xerostomia (p < 0.01). The radioisotope sialography study showed that the mean secretion ratio by acid stimulation was improved from 3.8% in the Group I to 15.2% in the Group II (p < 0.01). CONCLUSIONS: CT simulation was useful to determine the size and shape of each field to reduce the dose to the parotid gland, of which size varies largely among individual patients. The three-field technique based on CT simulation with laser patient markings is suggested to result in superior complication-free survival in terms of salivary dysfunction than did the conventional two-field technique with x-ray simulatior for NPC.

Adolescent↗

PubMed1997

Simultaneous determination of phospholipid hydroperoxides and cholesteryl ester hydroperoxides in human plasma by high-performance liquid chromatography with chemiluminescence detection.

A method was developed for the simultaneous determination of phosphatidylcholine hydroperoxides (PCOOH) and cholesteryl ester hydroperoxides (CEOOH). Lipid hydroperoxides (LOOH) were quantitatively extracted from human plasma with a mixture of n-hexane and ethyl acetate, and separated by column-switching high-performance liquid chromatography using one aminopropyl column and two octyl columns followed by chemiluminescence detection. LOOHs could be completely separated from each other and detected at picomole levels. The results of method validation tests were satisfactory. This method was then applied to determine LOOH in normal human plasma; the levels of PCOOH and CEOOH found were 36.0+/-4.0 nM (mean+/-S.D., n=6) and 12.3+/-3.1 nM (mean+/-S.D., n=6), respectively.

Cholesterol Esters↗