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Biomedical subjects

Y Wada

Publications and source records attributed to Y Wada.

At least 343 records · Page 19Linked to original sources
PubMed1998

Abnormal functional connectivity in Alzheimer's disease: intrahemispheric EEG coherence during rest and photic stimulation.

Electroencephalography (EEG) coherence provides a measure of functional correlations between two EEG signals. The present study was conducted to examine intrahemispheric EEG coherence at rest and during photic stimulation (PS; 5, 10 and 15 Hz) in ten unmedicated patients with presenile dementia of the Alzheimer type (AD; mean age at onset 56 years). In the resting EEG, the AD patients had significantly lower coherence than gender- and age-matched control subjects in the alpha-1, alpha-2 and beta-1 frequency bands. The EEG analysis during PS also showed that the patients had significantly lower coherence in the frequency corresponding to PS at 10 and 15 Hz. In this study, the changes in coherence from the resting state to the stimulus condition (i.e. PS-related coherence reactivity) were examined. The patients were found to show significantly smaller coherence reactivity to PS at 5 and 15 Hz. These findings suggest that, in addition to the resting state, AD patients have an impairment of intrahemispheric functional connectivity during PS. They also suggest that AD shows a failure of PS-related functional reorganization.

Aged↗
PubMed1998

Evidence of an increased risk of hearing loss in heterozygous carriers in a Wolfram syndrome family.

Wolfram syndrome (MIM 222300) is characterized by juvenile-onset diabetes mellitus and optic atrophy. Previous linkage analyses in the United States and UK families have indicated that the gene for Wolfram syndrome (WFS) is localized on the short arm of chromosome 4. We herein confirm the linkage of the WFS locus to D4S3023 on 4p with a two-point LOD score of 3.42 in a large Japanese family with Wolfram syndrome. Multipoint linkage analysis revealed the maximum LOD score of 4.82 between D4S3023 and D4S394. We also evaluated putative health risks in carriers by multiple logistic analysis with independent variables, age, gender, and numbers of affected haplotypes and with dependent variables, such as hearing loss, diabetes mellitus, polyuria, incontinence, psychological illness, and visual acuity. The results showed that the putative disease haplotype increased a risk of hearing loss (odds ratio =35.68, 95% confidence interval =4.12-308.95) and diabetes mellitus (odds ratio =7.57, 95% confidence interval =2.03-28.23) independently. This is the first report of an increased health risk of illness in carriers, other than for psychiatric disease.

Adolescent↗
PubMed1998

Malignant fibrous histiocytoma of the stomach: report of two cases.

Malignant fibrous histiocytoma (MFH) in the stomach is very rare, and only four cases have been reported. As a result, there is still little understanding of its clinical and pathological features. We recently experienced two cases of gastric MFH. The first case was a 78-year-old man with epigastralgia and a loss of body weight. Endoscopy revealed an ulcerated submucosal tumor. A gastrectomy was performed and the diagnosis of MFH was made histopathologically. The second case was a 77-year-old man with pulmonary symptoms. An image diagnosis indicated a strong suspicion of lung cancer, and a right middle and lower lobectomy was thus performed. One month after the operation, a bleeding gastric tumor was found and therefore a gastrectomy was performed. Both tumors were diagnosed as MFH. From the analysis of six reported cases including ours, a preoperative correct diagnosis is found to be difficult although the lesion has grown to a considerable size at the time of operation. Since a metastatic lung lesion was first detected in two out of six cases, it is thus recommended that the stomach should be examined when lung MFH is found. Considering the high mortality and the short survival in the six cases, the prognosis for gastric MFH seems to be poorer than that in the extremities. However, lymph node metastasis is uncommon, and a curative resection is possible in some cases such as in our second case.

Adult↗
PubMed1998

Tibial deformities and failures of anterior cruciate ligament reconstruction in immature rabbits.

We evaluated the effects of anterior cruciate ligament (ACL) reconstruction on growth and development of the knee in immature New Zealand white rabbits (8 weeks old). In 25 rabbits, the ACL was reconstructed with an autogenous iliotibial band (ITB), and in 31 rabbits an autogenous patellar tendon bone (PTB) graft was used. Reconstructed ACLs failed in 20 of the 25 animals in the ITB group and in 26 of 31 in the PTB group. Gross and histological examinations in the animals with successfully reconstructed ACLs (5 in the ITB group and 5 in the PTB group) showed significant tibial deformity and tibial shortening, with progressive thinning of the epiphyseal plate and disorders of the cartilage column on the medial side of the tibia. These abnormalities were not observed in rabbits whose ACLs were torn. This experiment showed that successful ACL reconstruction in young animals with an open physis may result in deformities and/or shortening of the leg. Accordingly, we believe that special care should be taken when surgically reconstructing an ACL in a young patient whose physes are still open.

Animals↗
PubMed1998

Transposition of the great arteries with anomalous origin of the left coronary artery from the pulmonary artery.

We describe an extremely rare case of successful arterial switch operation for an infantile complete transposition of the great arteries associated with ventricular septal defect and anomalous origin of the left coronary artery from the pulmonary artery in which the left main coronary artery arose from the posterior sinus of the pulmonary artery and the right coronary artery and an accessory branch arose from the aorta.

Cardiac Surgical Procedures↗
PubMed1998

Measurement of acetylcholine released from rabbit detrusor smooth muscle using HPLC with electro-chemical detection coupled with microdialysis procedure.

We measured the amount of acetylcholine (ACh) released from rabbit detrusor smooth muscles induced by electrical field stimulation (EFS) using microdialysis procedure. The dialysis probe was inserted through the detrusor muscle strip and was continuously perfused with a Ringer solution containing physostigmine sulfate, at a rate of 2 microl/min. The strip was suspended in an organ bath filled with the modified Krebs-Henseleit solution and then EFS was delivered. The isometric force was recorded and monitored in each muscle preparation. The dialysates were collected every 10 min. ACh was determined by a high performance liquid chromatography with electro-chemical detection. The contraction of the muscle strip and ACh release induced by EFS were increased in a frequency and duration dependent manner. There were some differences between frequency response curves of contraction and frequency dependent ACh release. In the contractile response, the maximum contractions were observed at lower frequencies, while ACh releases reached the maximum at higher frequencies. There was a significant, but not simple correlation between EFS-induced contraction and ACh release. The results suggest that this new method is useful to investigate the ACh release from rabbit detrusor smooth muscles, and that other neurotransmitters than ACh possibly contribute to EFS-induced contraction.

Acetylcholine↗
PubMed1998

Nitric oxide synthase inhibitor, aminoguanidine, reduces inflammation and demyelination produced by Theiler's virus infection.

This study evaluated effects of the inducible nitric oxide synthase (iNOS) inhibitor, aminoguanidine (AG), on the neuropathology and clinical disease produced by Theiler's murine encephalomyelitis virus (TMEV) DA strain infection. Treatment with AG was started on day 7, 14, 28 or 66 post-inoculation and continued for a minimum of 21 days. Inflammation, demyelination and axonal necrosis were scored in a blinded fashion on spinal cord sections from each mouse. Reduction in inflammation, demyelination and axonal necrosis was observed in mice treated with AG. Apoptosis within the spinal cord parenchyma and perivascular cuffs was significantly decreased. AG treatment resulted in delayed onset of clinical disease.

Animals↗
PubMed1998

Architectural remodeling in deep frozen meniscal allografts after total meniscectomy.

This study assesses the biological characteristics of cell repopulation and matrix remodeling in deep frozen meniscal allografts after total meniscectomy and allograft transplantation. Thirty-two mature New Zealand White rabbits were operated on, and the allografts were assessed at 12 and 26 weeks postsurgery. Before transplantation, fresh medial menisci were placed into liquid nitrogen to kill all intrinsic cells. Frozen meniscal allografts showed collagen remodeling coincident with revascularization and cellular repopulation. Biochemical characterization showed active collagen remodeling of the allografts at 12 and 26 weeks. In situ hybridization showed that expression of types I and III procollagen mRNAs were increased at 12 weeks, especially near the region of the synovial capsule. At 26 weeks after transplantation, the pattern of collagen-type expression progressed toward normal; that is, type I procollagen mRNA expression was prominent, whereas only a small amount of type III procollagen mRNA was observed. These data indicate the adaptation of the repopulating cells from the host to the frozen allograft at 26 weeks after transplantation.

Animals↗
PubMed1998

Changes in osteoblast phenotype during differentiation of enzymatically isolated rat calvaria cells.

Osteoblasts enzymatically isolated from newborn rat calvariae show various phenotypes including formation of mineralized bone nodules in culture. We investigated the temporal changes in osteoblast phenotype in these cells up to day 20 in culture. These cells formed unmineralized nodules by day 5. Mineralization was observed at the center of nodules by day 10, and nodules became larger on day 15. The nodules were surrounded by numerous alkaline phosphatase (ALP)-positive cells. ALP activity gradually increased by day 20. Parathyroid hormone (PTH) responsiveness increased with time in culture. Osteoblasts produced no osteocalcin by day 10, but its synthesis was detected from day 15. These cells expressed substantial levels of ALP and PTH/PTHrP receptor mRNAs as early as day 5 in culture, but very weak expression of osteocalcin mRNA on day 5. The levels of expression of these transcripts increased with time in culture. In situ hybridization demonstrated that PTH/PTHrP receptor and osteocalcin mRNAs were strongly expressed in nodules, but the former appeared much earlier than the latter. BMP-2 and BMP-4 mRNAs also appeared in the cells forming nodules. Immunohistochemical analysis demonstrated that cells expressing either BMP-2/4 or their receptors (BMPR-IA, BMPR-IB, and BMPR-II) preferentially appeared in nodules. These observations suggested that BMPs play an important role in the formation of mineralized bone nodules in an autocrine and/or paracrine fashion in these cells. The present study confirmed that osteoblasts enzymatically isolated from newborn rat calvariae are a useful tool for studying the differentiation process of osteoblasts.

Alkaline Phosphatase↗
PubMed1998

A catalytic antibody that accelerates the hydrolysis of carbonate esters. Prediction of the binding-site structure of the substrate.

Monoclonal antibodies catalyzing the hydrolysis of p-nitrophenyl alkyl carbonate were obtained using p-nitrophenyl phosphonate as hapten. One of the antibodies, 4A1, has a relatively high activity for the substrate having a bulky group. To determine the amino acid residues related to the binding of the bulky group, we determined the amino acid sequences of VL and VH regions of 4A1 by the cycle sequencing method, built the three-dimensional structure of the V regions, labeled 4A1 with [14C]phenyl glyoxal in the presence and absence of I-1 or I-13, and analyzed the labeled incubation mixture with SDS-PAGE. From these results, the possibility that Arg-H28 of the heavy chain is involved in binding the bulky group of the substrate is discussed.

Amino Acid Sequence↗
PubMed1998

Comparison of chromosomal aberrations detected by fluorescence in situ hybridization with clinical parameters, DNA ploidy and Ki 67 expression in renal cell carcinoma.

To evaluate the significance of chromosomal aberrations in renal cell carcinoma, fluorescence in situ hybridization (FISH) was used to determine its prevalence and correlation with clinical parameters of malignancy. In addition, correlation of chromosomal aberration with Ki 67 expression was analysed. We performed FISH with chromosome-specific DNA probes, and the signal number of pericentromeric sequences on chromosomes 3, 7, 9 and 17 was detected within interphase nuclei in touch preparations from tumour specimen. The incidence of loss of chromosome 3 was significantly higher than those of chromosomes 7, 9 and 17 (P < 0.001, P = 0.03 and P < 0.001 respectively). Hyperdiploid aberration of chromosomes 3 and 17 was significantly correlated with tumour stage (P = 0.03, P = 0.02 respectively), whereas hyperdiploid aberration of chromosome 9 was associated with nuclear grade (P = 0.04). Disomy of chromosome 7 was correlated with venous involvement (P = 0.04). Ki 67 expression was significantly associated with hyperdiploid aberration of chromosome 17 (P = 0.01), but not with aberration of chromosome 3. There was a significant relationship between hyperdiploid aberration of chromosome 7 and Ki 67 expression (P = 0.01). In conclusions, gain of chromosome 17 may reflect tumour development, and aberration of chromosome 7 may affect metastatic potential of malignancy, whereas loss of chromosome 3 may be associated with early stage of tumour development in renal cell carcinoma.

Adult↗
PubMed1998

Dipole analysis of epileptic source generator with manual zero potential shifting method.

The dipole tracing method is a technique whereby an electric source generator is estimated as an equivalent current dipole (ECD) based on potential distribution on the scalp. To estimate the electric source generator of low amplitude spikes, a manual zero potential shifting (MZPS) method was introduced in which a zero potential is set manually in dipole analysis. The subjects were three patients with localization-related epilepsy with temporal spikes. When low-amplitude spikes (< 50 microV) were analyzed by the conventional mean zero potential method, the dipolarity, an indicator of ECD reliability, had a low value and its locations were scattered. In contrast, when these low-amplitude spikes were analyzed by the MZPS method, ECD showed a high dipolarity value comparable to that obtained when high-amplitude spikes (> or = 50 microV) were analyzed by the mean zero potential method. Furthermore, the locations of the former ECD tended to converge and were almost identical to those of the latter ECD. These findings suggest the usefulness of the MZPS method in dipole analysis in terms of the dipolarity and ECD locations of low-amplitude spikes.

Action Potentials↗
PubMed1998

Heat-induced membrane damage combined with adriamycin on prostate carcinoma PC-3 cells: correlation of cytotoxicity, permeability and P-glycoprotein or metallothionein expression.

OBJECTIVE: To assess heat-induced membrane damage in a prostate cancer cell line when combined with adriamycin treatment. MATERIALS AND METHODS: The changes in intracellular adriamycin accumulation, cell proliferation and cell-cycle fractions were examined after human prostate carcinoma PC-3 cells were exposed to heat and/or further treatment with adriamycin. Proliferation and the cell cycle were determined using adherent cell analysis and sorting laser cytometry (ACAS) or flow cytometry. P-glycoprotein (PGP) and metallothionein (MT) expression, which may have a physiological role in the transport of or reduction in cytotoxicity of some anticancer drugs, were also analysed after cells were exposed to heat, using immunohistochemical or flow cytometric methods. RESULTS: There was a significant increase in intracellular adriamycin accumulation, related to both influx (P<0.05) and efflux (P<0.01), in cells treated with adriamycin, especially after heating them at 44 degrees C for 1 h. There was a significant decrease in cell proliferation of preheated cells when exposed to adriamycin, especially at 44 degrees C (P<0.05). In the cell-cycle analysis, cells preheated at 44 degrees C showed partial accumulation in the debris or apoptotic fraction at 24 h, and many cells accumulated in these fractions at 48 h. There was significantly less PGP or MT expression in cells preheated at 44 degrees C than in control cells or cells preheated at 41 degrees C (P<0.01). This reduction in PGP or MT level by heating may inhibit drug efflux and thus increase intracellular drug level at elevated temperatures. CONCLUSIONS: These results suggest that hyperthermia may damage the drug-exclusion mechanism in these cells and thus increase the effectiveness of drug action.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1998

Dihydropyrimidinase deficiency: structural organization, chromosomal localization, and mutation analysis of the human dihydropyrimidinase gene.

Dihydropyrimidinase (DHP) deficiency (MIM 222748) is characterized by dihydropyrimidinuria and is associated with a variable clinical phenotype. This disease might be associated with a risk of 5-fluorouracil toxicity, although no cases have been reported. We present here both the molecular characterization of the human DHP gene and, for the first time, the mutations causing DHP deficiency. The human DHP gene spans >80 kb and consists of 10 exons. It has been assigned to 8q22, by FISH. We performed mutation analysis of genomic DNA in one symptomatic and five asymptomatic individuals presenting with dihydropyrimidinuria. We identified one frameshift mutation and five missense mutations. Two related Japanese adult subjects were homozygous for the Q334R substitution, whereas two other, unrelated Japanese infant subjects were heterozygous for the same mutation, but this mutation is not common in the Japanese population. A Caucasian pediatric patient exhibiting epileptic attacks, dysmorphic features, and severe developmental delay was homozygous for W360R. Using a eukaryotic expression system, we showed that all mutations reduced enzyme activity significantly, indicating that these are crucial DHP deficiency-causing mutations. There was no significant difference, in residual activity, between mutations observed in the symptomatic and those observed in the asymptomatic individuals.

Adult↗
PubMed1998

Comparisons of rice field mosquito (Diptera: Culicidae) abundance among areas with different agricultural practices in northern Thailand.

Adult mosquitoes were collected from 3 areas in northern Thailand with different availabilities of rice fields for larval habitats by using blacklight, truck, and pig-baited traps. Culex tritaeniorhynchus Giles and Culex gelidus Theobald were dominant in all samples. Significant study-area differences were found in light and truck trap collections for Cx. tritaeniorhynchus and Cx. gelidus, but not for Culex vishnui Theobald + Culex pseudovishnui Colless. In pig-baited sample area differences were significant only for Cx. gelidus. Adults of Culex fuscocephala Theobald were relatively rare, comprising only 0.6-7.9% of the total mosquitoes collected. When compared with the results from previous studies in the Chiangmai area, we conclude that Cx. fuscocephala has become a minor species and that changes in the mosquito fauna have occurred in northern Thailand.

Agriculture↗
PubMed1998

Diverse roles of single membrane organelles: factors establishing the acid lumenal pH.

Eukaryotic cells have developed an array of endomembrane systems that have differentiated to carry out various functions. They are involved in the pathways of endocytosis and exocytosis, and have an acidic lumenal pH ranging from 4.5 to 6.5. This review describes recent studies on the animal cell organelles and how they relate to the well studied systems of yeast. We focus mainly on (i) the primary proton pump (vacuolar type H+-ATPase) and other factors that establish acidic pH, and (ii) functions of the organelles as related to lumenal acidity.

Animals↗