Biomedical subjects

M Mizutani

Publications and source records attributed to M Mizutani.

At least 37 records · Page 2Linked to original sources

PubMed2001

Limited association between a catechol-O-methyltransferase (COMT) polymorphism and breast cancer risk in Japan.

BACKGROUND: Catechol-O-methyltransferase (COMT) inactivates the estradiol metabolites, 2-hydroxy estradiol and 4-hydroxy estradiol. To date, three studies in Caucasians and one study in Chinese have been conducted to determine the association with breast cancer risk of a functional polymorphism (G-to-A, Val158Met) of this enzyme, but the results were inconsistent. In order to examine the impact of this polymorphism on breast cancer risk in Japan, a case-control study was conducted, at Aichi Cancer Center Hospital. METHODS: The cases were 150 patients with histologically confirmed breast cancer who had been diagnosed within 4 years before enrollment at this hospital. The controls were 165 non-cancer patients, mainly from the gastroenterology and breast surgery clinics at the hospital. COMT-H (Val) is the wild-type allele, with high enzyme activity, while the COMT-L (Met) allele has low activity. Genotyping was conducted by a polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method. RESULTS: The allele frequency of COMT-L was 36.0% for cases and 33.0% for controls. Age-adjusted odds ratios relative to the COMT-HH genotype were 1.46 (95% confidence interval [CI], 0.90-2.36) for COMT-HL, and 0.99 (95% CI, 0.49-2.02) for the COMT-LL genotype. Significant odds ratios were not observed for any subgroup stratified by menopausal status, age at menarche, age at birth of first child, body mass index, and breast cancer history of mother and/or sister(s). CONCLUSION: The present study suggested that any association of the COMT polymorphism with breast cancer risk is limited in Japanese.

Adult↗

PubMed2001

Effect of digoxin noncompliance on hospitalization and mortality in patients with heart failure in long-term therapy: a prospective cohort study.

BACKGROUND: As outpatients with long-term chronic illness often show a high incidence of medication noncompliance, we investigated the influence of digoxin noncompliance on hospitalization, left ventricular ejection fraction, and mortality in outpatients in long-term therapy having congestive heart failure with tachycardia at a rate over 100 beats/min before starting digoxin therapy, but abnormal sinus rhythm. METHODS: Before starting this study, the digoxin compliance/noncompliance of patients was determined by measuring the serum digoxin concentration (SDC). SDC was determined once a month, followed for six consecutive months, and patients were defined as noncompliant if their SDC was zero (0.0 ng/ml) on at least three consecutive occasions. According to SDC data, 218 patients were assigned to the compliant group and 213 patients were assigned to the noncompliant group. All 431 patients received diuretics, angiotensin converting-enzyme inhibitors, or nitrates as well as conventional therapy with digoxin throughout the trial. The duration of follow-up was 72 months. FINDINGS: After 72 months of follow-up, the digoxin noncompliant patients showed significant increases in the number and duration of hospitalizations compared with the compliant patients. The digoxin noncompliant patients had a marked decrease in the left ventricular ejection fraction from 49.1% to 41.8%. The cumulative rate of mortality from any cause in noncompliant patients was twofold higher (15.0%) than in compliant patients (7.8%; risk ratio when noncompliant was compared with compliant: 1.95; 95% confidence interval 1.11, 3.45; P = 0.029) at the 72-month follow-up. The higher mortality in digoxin noncompliant patients was exclusively attributed to worsening heart failure rather than other cardiac and noncardiac causes (risk ratio 2.13; 95% confidence interval 1.12, 4.07; P = 0.033). In addition, multiple regression analyses demonstrated that patient noncompliance as well as lower left ventricular ejection fraction at baseline were significantly involved in increased mortality. CONCLUSION: These results indicate that digoxin noncompliance, at least in part, increases the rate of both hospitalization and mortality due to worsening heart failure in outpatients who have congestive heart failure with tachycardia in long-term therapy.

Aged↗

PubMed2001

Analysis of 168 short tandem repeat loci in the Japanese population, using a screening set for human genetic mapping.

We devised a multiplex polymerase chain reaction (PCR) amplification and loading system for the convenient typing of 168 short tandem repeat (STR) polymorphic markers in a commercially available screening primer set for human linkage analysis. We genotyped all these 168 STR loci with 32 healthy unrelated Japanese, calculated allele frequencies at each STR locus, and performed three kinds of tests for Hardy-Weinberg equilibrium (HWE). Significant deviations from HWE in all three tests were observed at only three loci, and the average heterozygosity in the Japanese (0.733) was slightly lower than that in Caucasians (0.773). We also examined 32 Caucasians at some selected loci, to be compared with Japanese. Some markers showed greatly different heterozygosities or allelic distributions in Japanese and Caucasian populations. In two groups of STRs, those with and without irregular alleles (or interalleles), the former had a higher proportion of bimodal allelic distribution and possessed more alleles per locus than the latter. However, no significant differences in the observed and expected heterozygosities, or in the powers of discrimination, were found between the two groups. The present basic study of allele frequency databases of these STRs will contribute to further applications in forensic science and human genetics.

Gene Frequency↗

PubMed2001

Electrophysiological measures of auditory function in the neurofilament-deficient mutant quail (Quv).

Auditory pathway electrophysiological studies were performed on the mutant quail 'Quv'. This mutation is known to result in neurofilament deficiencies of both the peripheral and central nervous systems. Auditory evoked brainstem responses (ABRs), electrocochleograms (EcochGs) and middle latency responses (MLRs) were evaluated. ABRs in Quv quails demonstrated markedly altered waveforms exhibiting longer latencies, absence of the later peaks and lower amplitudes. The EcochG showed normal cochlear microphonics with no obvious abnormalities in amplitude or latency and normal latencies for peak N1. Quv quails had a mild threshold elevation with a normal latency for the first peak of the ABR (P1). The Quv MLRs showed no significant differences in amplitude but they revealed a latency prolongation for peaks N0, Pa and Na relative to the controls. We have discovered abnormal findings of auditory evoked potentials in the neurofilament-deficient quail (Quv). We suggest that the smaller axonal size and axonal hypotrophy due to altered neurofilament expression underlies these abnormal auditory evoked potential responses.

Acoustic Stimulation↗

PubMed2001

Auditory nerve fiber differences in the normal and neurofilament deficient Japanese quail.

A primary axonal disease affecting the central and peripheral nervous system was discovered in a mutant strain of the Japanese quail, named quiver (Quv). We have previously demonstrated altered auditory evoked potentials in the neurofilament (NF) deficient quail. In this current study we attempt to find relationships between the auditory evoked potential results and the histo-pathological abnormalities of the auditory neurons. No abnormalities in the external auditory meatus and tympanic cavity were observed in either Quv or control quails and the ganglion cell bodies and their nuclei appeared normal by light microscopy. The myelin staining pattern was found to be similar in both strains with hematoxylin and eosin and Klüver-Barrera staining. The frequency histograms of fiber and axonal diameters of myelinated fibers showed an unimodal pattern in both strains. In Quv quails myelinated fibers and their axoplasm were smaller in diameter than in controls resulting in smaller neural tissue mass. In electron microscopic observation the axons of the Quv quail were composed of mitochondria and microtubules and smooth endoplasmic reticuli. In Quv quail electron micrographs of cochlear nerve myelinated fibers NFs were not seen in the axons and the neuronal cell bodies. Our current findings indicate that the previously reported reduction of conduction velocity of auditory evoked potentials may be due to smaller fiber and/or axonal diameter. The g-ratio, myelin thickness and fiber circularity were found to be the same for both strains. In conclusion, loss of axonal cytoskeletal elements (NFs) correlates well with our electrophysiological findings. Reduced conduction velocity and severely distorted auditory evoked potentials in NF deficient quails seem to be primarily due to axonal hypotrophy.

Animals↗

PubMed2001

Chicken microsatellite primers are not efficient markers for Japanese quail.

Domestic fowl or chicken (Gallus gallus) and Japanese quail (Coturnix japonica) belong to the family Phasianidae. The exchange of marker information between chicken and quail is an important step towards the construction of a high-resolution comparative genetic map in Phasianidae, which includes several poultry species of agricultural importance. We tested chicken microsatellite markers to see if they would be suitable as genetic linkage markers in Japanese quail. Twenty-six per cent (31/120) of chicken primers amplified individual loci in Japanese quail and 65% (20/31) of the amplified loci were found to be polymorphic. Eleven of the polymorphic loci were excluded as uninformative because of the lack of amplification in some individuals or high frequency of nonspecific amplification. The sequence information of the remaining nine loci revealed six of them to contain microsatellites that were nearly identical with those of the orthologous regions in chicken. For these six loci, allele frequencies were estimated in 50 unrelated quails. Although the very few chicken markers that do work well in quail could be used as anchor points for a comparative mapping, most chicken markers are not useful for studies in quail. Therefore, more effort should be committed to developing quail-specific markers rather than attempting to adapt chicken markers for work in quail.

Animals↗

PubMed2001

Analysis of tyrosine phosphorylation-dependent protein-protein interactions in TrkB-mediated intracellular signaling using modified yeast two-hybrid system.

Activated receptor tyrosine kinases induce a large number of tyrosine phosphorylation-dependent protein-protein interactions through which they mediate their various ligand-exerted functions including regulation of proliferation, differentiation and survival. TrkB receptor tyrosine kinase activated by binding of brain-derived neurotrophic factor (BDNF) also stimulates various protein interactions in a tyrosine phosphorylation-dependent manner in neuronal cells. To examine tyrosine phosphorylation-dependent interactions stimulated by active TrkB, we developed a modified yeast two-hybrid system, which we call the yeast two-and-a-half-hybrid system. In this system, yeast was engineered to express a tyrosine kinase domain of TrkB as an effector, in addition to two fusion proteins with GAL4 DNA-binding and GAL4 activation domains as bait and prey proteins, respectively. Using this system with Shp2 as the bait, we demonstrated that Shp2 interacts directly with BIT/SHPS-1 (also called SIRP) and Grb2 depending on tyrosine phosphorylation mediated by TrkB. Furthermore, we screened an adult human brain cDNA library with the yeast two-and-a-half-hybrid system in order to identify other Shp2-binding proteins in TrkB-stimulated tyrosine phosphorylation signaling. We found that fibroblast growth factor receptor substrate 2beta (FRS2beta), also called SNT2, interacts with Shp2 dependently on TrkB-mediated tyrosine phosphorylation of FRS2beta/SNT2. Therefore, we show that the two-and-a-half-hybrid system is a powerful tool for studying tyrosine phosphorylation-dependent protein-protein interactions in intracellular signaling pathways stimulated by TrkB receptor tyrosine kinase.

Adaptor Proteins, Signal Transducing↗

PubMed2001

Substrate specificity of beta-primeverosidase, a key enzyme in aroma formation during oolong tea and black tea manufacturing.

We synthesized nine kinds of diglycosides and a monoglycoside of 2-phenylethanol to investigate the substrate specificity of the purified beta-primeverosidase from fresh leaves of a tea cultivar (Camellia sinensis var. sinensis cv. Yabukita) in comparison with the apparent substrate specificity of the crude enzyme extract from tea leaves. The crude enzyme extract mainly showed beta-primeverosidase activity, although monoglycosidases activity was present to some extent. The purified beta-primeverosidase showed very narrow substrate specificity with respect to the glycon moiety, and especially prominent specificity for the beta-primeverosyl (6-O-beta-D-xylopyranosyl-beta-D-glucopyranosyl) moiety. The enzymes hydrolyzed naturally occurring diglycosides such as beta-primeveroside, beta-vicianoside, beta-acuminoside, beta-gentiobioside and 6-O-alpha-L-arabinofuranosyl-beta-D-glucopyranoside, but were unable to hydrolyze synthetic unnatural diglycosides. The purified enzyme was inactive toward 2-phenylethyl beta-D-glucopyranoside. The enzyme hydrolyzed each of the diglycosides into the corresponding disaccharide and 2-phenylethanol. These results indicate the beta-primeverosidase, a diglycosidase, to be a key enzyme involved in aroma formation during the tea manufacturing process.

Carbohydrate Sequence↗

PubMed2001

Effects of brewer's yeast cell wall on constipation and defecation in experimentally constipated rats.

Brewer's yeast cell wall (BYC) was tested on constipated male Sprague-Dawley rats that had been induced by loperamide (2 mg/kg of body weight). The preventive effect of BYC on constipation was examined and compared with that of a non-fiber diet (NF) as the control. The dose-response of BYC and the effect on defecation by constipated experimental rats were also compared with the characteristics of cellulose diet (CE) group which served as a control. Defecation was observed to be greater by the rats fed with BYC than by those fed with NF or CE. The fecal water content and level of volatile fatty acids (VFA) in the cecal contents were likewise higher in the rats fed with BYC. These results indicate that the administration of BYC was effective for improving defecation and other parameters related to defecation. These favorable effects of BYC supplemented to the diet are attributed to the fermentation ability, water holding capacity and swelling force in the large intestine.

Antidiarrheals↗

PubMed2001

Histopathologic features of masseter muscle in the distrophic hamster (UM-X7.1 Syrian hamster).

Dystrophic hamster has been regarded as the useful model animal for Severe childhood autosomal recessive muscular dystrophy (SCARMD). Although, many studies on Dystrophic hamster have utilized the muscular tissue of the trunk, however no study have been analyzed for the masticatory muscle. For this study, we used a Dystrophic hamster (UM-X7.1 Syrian hamster) to histochemically investigate the effect of muscular dystrophy on the masseter muscle. Large and small regenerated muscle fibers, and necrotic fibers were detected almost in all areas. Opaque fiber, hypertrophic fiber with fiber splitting structure and necrotic fiber filled up by mononuclear phagocytes were recognized. The region, in which the mononuclear phagocytic cells infiltrated, showed strong positivity to acid phosphatase, and lysosome enzyme. There were many muscle fibers with reduced levels of succinate dehydrogenase (SDH) activities in the muscle fiber. Some TUNEL-positive cells were confirmed in both necrotic and non-necrotic areas. It was suggested that a part of TUNEL-positive cells are the cells originated from the connective tissue or immunocytes. In this result, histopathologic changes of the masseter muscle of the UM-X7.1 Syrian hamster was similar to muscle of the body trunk in the past reports. As the result, it was suggested that jaw closing movements may be negatively affected caused by the decline of the masseter muscle twitch. And, the point of view by which apoptosis is the trigger for the muscle fiber collapse were not seen in the Dystrophic hamster masseter muscle. We suggest that apoptosis is a one step in the process of regeneration of muscle fibers.

Acid Phosphatase↗

PubMed2001

Effects of yogurt supplemented with brewer's yeast cell wall on constipation and intestinal microflora in rats.

Brewer's yeast cell wall (BYC) is a valuable foodstuff that prevents constipation in rats. In this study, the effects of yogurt supplemented with brewer's yeast cell wall (BYC-Y) on constipated male Sprague-Dawley rats induced by loperamide (2 mg/kg body weight) were investigated. The preventive effect of BYC-Y on experimentally constipated rats was examined and compared with that of nonfiber diet (Control) and standard yogurt (Yogurt) as the control diets. The number of feces and fecal dry weight were greater in rats fed with BYC-Y than in those fed with Control or Yogurt. Moreover, the effect of BYC on the improvement of cecal microflora in constipated experimental model rats was evaluated. The number of Lactobacillus, Eubacterium, and total anaerobes per unit cecal contents increased (p<0.03) as a result of BYC ingestion. These findings indicate that BYC-Y or BYC is effective for the alleviation of constipation and bowel environment.

Animals↗

PubMed2001

The application of minisatellite variant repeat mapping by PCR (MVR-PCR) in a paternity case showing false exclusion due to STR mutation.

A boy and a girl with their mother brought a paternity suit against an alleged but deceased father. We tested six conventional genetic markers, the AmpliType PM+ DQA1 and twelve STR loci the children and mother together with the alleged paternal grandparents. We also DNA typed the bloodstain found later in the alleged father's medical record. Only the result at D3S1358 in a nineplex STR system excluded the alleged father from parentage of the boy, whereas all markers were inclusive for the girl. Accordingly, we performed sequence analysis at D3S1358 to confirm the presence of a paternal exclusion or mutation. The sequence analysis indicated that the boy's allele 17 could have originated from either of the alleged father's allele 16 or 18 by a single-step mutation associated with slippage mutation in STR loci. We carried out minisatellite variant repeat mapping by PCR (MVR-PCR) at loci D1S8 (MS32) and D7S21 (MS31A) and mapped allele haplotypes of all individuals except the deceased alleged father. The MVR-PCR analysis showed that the boy has no inconsistency with the relationship between the alleged grandparents, and was very effective at increasing the paternity index (PI) value. We conclude that there is biological relationship between not only the girl but also the boy and the alleged father.

Adult↗

PubMed2001

A new triplex STR system without irregular alleles by silver staining and its potential application to forensic analysis.

In order to increase the discriminating power of DNA analysis in forensic science, we devised a new triplex STR system using three novel STR loci we previously reported, D14S299 (wglc5), D15S233 (wgldl), and 9q2h2. We designated this system a CDH triplex system. The CDH triplex system showed a high discriminating power, especially in Caucasians. This system is composed of three STR loci showing only regular tetranucleotide repeat alleles. We easily enlarged the databases mainly of Japanese, using this system, and compared them with those of Caucasian and Chinese. This CDH triplex system therefore appears to be useful for forensic practice.

Alleles↗

PubMed2000

2',5'-oligoadenylate synthetase gene in chicken: gene structure, distribution of alleles and their expression.

We have cloned the gene for chicken 2',5'-oligoadenylate synthetase (ChOAS) by the method of polymerase chain reaction with use of ChOAS cDNA sequence. The ChOAS gene is composed of five introns and six exons containing all of the sequence of the ChOAS cDNA from the start to the stop codon. The first five exons of ChOAS gene which encode the OAS catalytic domain have a similar structure to HuOAS1 gene including the exon-intron boundaries. However, the length of introns of ChOAS gene is only 1/7 of those of HuOAS1 gene. The sixth exon of the ChOAS gene encodes the ubiquitin-like (UbL) domain of two consecutive sequence (UbL1 and UbL2) homologous to ubiquitin. ChOAS encoded in a single copy gene has at least two alleles, OAS(*)A and OAS(*)B. The differences between these two alleles are in the sixth exon of the gene; a 96-nucleotide sequence in the UbL1 portion of OAS(*)A is deleted from OAS(*)B. No OAS(*)B gene was detected in nine lines of chickens tested other than Leghorns. Almost the same levels of ChOAS-A and -B proteins induced physiologically in erythrocytes were detected in infant chickens (2-week-old), but in grown-up chickens (6-month-old) the level of erythrocyte OAS-B was markedly reduced in most of B/B chickens. Thus, the UbL domain of ChOAS is responsible for the maintenance of the OAS level in the tissue.

2',5'-Oligoadenylate Synthetase↗

PubMed2000

Selected mutations in a mesophilic cytochrome c confer the stability of a thermophilic counterpart.

Mesophilic cytochrome c(551) of Pseudomonas aeruginosa (PA c(551)) became as stable as its thermophilic counterpart, Hydrogenobacter thermophilus cytochrome c(552) (HT c(552)), through only five amino acid substitutions. The five residues, distributed in three spatially separated regions, were selected and mutated with reference to the corresponding residues in HT c(552) through careful structure comparison. Thermodynamic analysis indicated that the stability of the quintuple mutant of PA c(551) could be partly attained through an enthalpic factor. The solution structure of the mutant showed that, as in HT c(552), there were tighter side chain packings in the mutated regions. Furthermore, the mutant had an increased total accessible surface area, resulting in great negative hydration free energy. Our results provide a novel example of protein stabilization in that limited amino acid substitutions can confer the overall stability of a natural highly thermophilic protein upon a mesophilic molecule.

Bacteria↗

PubMed2000

The effect of SK-896 on post-operative ileus in dogs: gastrointestinal motility pattern and transit.

The aim of this study was to investigate the effect of SK-896 (Phe-Val-Pro-Ile-Phe-Thr-Try-Gly-Glu-Leu-Gln-Arg-Leu-Gln-Glu-Lys-Glu- Arg-Asn-Lys-Gly-Gln-Hse), a new motilin analogue, on gastrointestinal motility and transit in dogs with post-operative ileus, and to compare the effects of this agent on these parameters with the effects of prostaglandin F(2alpha), a well-known gastroprokinetic agent. We used chronically implanted force transducers to measure motility and radiography of radio-opaque markers to measure transit. Infusion of SK-896 1 microgram/kg/h, for 20 min twice a day induced interdigestive migrating contractions-like motility. Infusion of prostaglandin F(2alpha), 20 microgram/kg/h, for 1 h twice a day induced continuous contractions in the distal part of the small intestine. The time of first appearance of interdigestive migrating contractions in the stomach (gastric-interdigestive migrating contractions) and the gastric emptying time of the solid marker with the administration of SK-896 were significantly less than those noted with the administration of prostaglandin F(2alpha). It appears that gastric-interdigestive migrating contractions play an important role in the transit of substances, especially solid substances, in the gastrointestinal tract. We conclude that SK-896, which induced gastric-interdigestive migrating contractions, is effective to induce early recovery from post-operative ileus.

Amino Acid Sequence↗

PubMed2000

Effect of hypoxia on nitric oxide production and its synthase gene expression in rat smooth muscle cells.

It has not been clarified yet as to whether hypoxia and inflammation affect NO synthesis. In this study, we investigated the transcription of inducible nitric oxide synthase (iNOS) mRNA and the production of nitric oxide (NO) in rat smooth muscle cells (SMCs) cultured under hypoxic conditions in the presence and absence of proinflammatory cytokine interferon-gamma (IFN-gamma) and lipopolysaccharide (LPS). We found that hypoxia inhibited the production of NO but did not affect the transcription of iNOS mRNA in rat SMCs treated with IFN-gamma, LPS, or both. These results indicate that O(2) is involved in the regulation of NO synthesis in inflammatory tissues.

Animals↗

PubMed2000

A case of metastatic breast cancer achieving complete response by combination therapy with 5'-deoxy-5-fluorouridine and cyclophosphamide.

Recently there have been several reports on the effectiveness of combination chemotherapy with 5'-deoxy-5-fluorouridine (5'-DFUR) and cyclophosphamide (CPA) for treating recurrent breast cancer. We report a case in which treatment of local recurrence and lung metastases responded was remarkably effective by this combination chemotherapy. A 45-year-old woman underwent modified radical mastectomy for left breast cancer (T2N0M0) three years previously. Involvement of a left supraclavicular lymph node (ScLN) and multiple lung metastases were revealed 2 years and 6 months after the operation. First, we opted for systemic endocrine therapy with local irradiation for the lung metastases and ScLN. However the lung metastases were found to have increased on chest x-ray 2 months after treatment, showing progressive disease (PD). A locally recurrent new lesion sized 2 x 2 cm had also developed. Thus, we changed the treatment to combination chemotherapy with 5'-DFUR 800 mg/body and oral CPA 100 mg/body once a day. The lung metastases had disappeared on chest x-ray and the local recurrence was not palpable after 7 weeks of the new treatment. Thymidine phosphorylase (dThdPase) immunostaining of the primary tumor was strongly positive in almost all cancer cells. We discuss the mechanism of the increased efficacy of combination chemotherapy with 5'-DFUR and CPA.

Antineoplastic Combined Chemotherapy Protocols↗