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K Shiga

Publications and source records attributed to K Shiga.

At least 19 recordsLinked to original sources
PubMed2006

Exploration of genes showing intramuscular fat deposition-associated expression changes in musculus longissimus muscle.

Marbling, as defined by the amount of intramuscular fat, is an economically important trait in beef cattle. Intramuscular fat deposition is postulated to arise mainly from a series of adipogenic events in intramuscular adipocyte-lineage cells and in the physiological or anatomical milieux surrounding them. This study was designed to investigate gene-expression patterns associated with fat deposition in musculus longissimus muscle, including adipocyte-lineage cells and part of the milieux. Differential-display PCR (ddPCR) was used to examine expression differences between low-marbled and high-marbled steer groups at 8, 10, 12 and 14 months of age, encompassing the time that marbling starts to appear. Seventy-four of 2114 total bands on ddPCR gel-bands were significant (P < 0.05) for the group effect, the interaction effect between group and age, or both the group and the interaction effects. Sequence analysis of 72 of these bands revealed 77 genes, including 35 annotated genes and 42 novel sequences. Among the 35 annotated genes, 6 (BTG2, PDHB, SORBS1, TRDN, TTN and MGP) have been related to changes in intramuscular fat deposition, possibly by exerting effects on adipocyte-lineage cells or on the milieux surrounding them.

Adipose Tissue↗
PubMed2005

Effect of copper and diethyldithiocarbamate combination therapy on the macular mouse, an animal model of Menkes disease.

Menkes disease (MD) is a neurodegenerative disorder characterized by a copper deficiency in the brain. It is caused by the defective intestinal absorption of copper resulting from a deficiency of a copper-transporting ATPase, ATP7A. This gives rise to an accumulation of copper in the intestine. The copper deficiency in the brain of MD patients cannot be improved by copper injections, because the administered copper accumulates at the blood-brain barrier and is not transported across to the neurons. To resolve this problem, we investigated the effect of a combination therapy of copper and sodium diethyldithiocarbamate (DEDTC), a lypophilic chelator, in an animal model of MD, the macular mouse. Four-week-old macular mice treated with 50 mug of CuCl2 on the 7th day after birth were used. Experimental mice were given a subcutaneous injection of CuCl2 (4 microg) and an intraperitoneal injection of DEDTC (0.2 mg/g body weight) twice a week for 4 weeks and then sacrificed. Copper concentrations and cytochrome-c oxidase activity in the brains of treated mice were higher than those of control macular mice, which received only copper or saline. The ratios of brain noradrenaline to dopamine and of adrenaline to dopamine were also increased by the treatment, suggesting that the activity of dopamine beta-hydroxylase, a copper-dependent enzyme, was improved by the treatment. Liver and renal function tests showed no abnormalities in the treated mice, although copper concentrations in the kidneys of treated mice were higher than those of control macular mice. These results suggest that DEDTC facilitates the passage of copper across the blood-brain barrier and that the combination therapy of copper and DEDTC may be an effective treatment for the neurological disturbances suffered by patients with MD.

Animals↗
PubMed2005

A survey of Japanese patients with Menkes disease from 1990 to 2003: incidence and early signs before typical symptomatic onset, pointing the way to earlier diagnosis.

Menkes disease (MNK) is a lethal, X-linked recessive disorder of copper metabolism dominated by neurodegenerative symptoms and connective tissue disturbances. The incidence of MNK in Asia is not known. Most patients die by the age of 3 years if adequate treatment is not carried out. Early parenteral administration of copper can prevent the neurological disturbances and lead to a better outcome. In the present study, a survey on MNK in Japan was performed. There were in total 53 live-born Japanese patients with MNK collected from 1990 to 2003, including two females. The incidence of live-born MNK patients between 1992 and 2002 was 2.8 per million live births (95% confidence interval (CI): 1.8 to 3.7), 4.9 per million male live births (95% CI: 3.2 to 6.6). One-third of the patients were born before 37 weeks or weighing less than 2500 g. Seventeen per cent were born both before 37 gestational weeks and weighing less than 2500 g. These proportions were higher than those in Japanese live-birth babies according to a nationwide estimate. The hair on these Japanese patients appeared not only as white or grey but also brown and blond. We also found that many signs had been noted before the patient was brought to a hospital with typical symptoms. These signs may be a clue to early diagnosis of MNK.

Age Factors↗
PubMed2005

Linkage analysis reveals two independent loci for ocular disorders in a local Japanese Black cattle population.

A vision-impairing ocular disorder was observed in a local Japanese Black cattle population, and assumed to be an autosomal recessive disease based on the presence of a founder cow. A genome scan using seven affected half-sib pairs revealed a linkage to BTA5 (Z(max) = 7.0, LOD(max) = 2.0), designated the bovine ocular disorder 1 (bod1) locus. Of the seven animals, three were heterozygous at the bod1 locus. Analysis in these three animals revealed linkage to markers on BTA18, and this locus was designated bod2. Detailed haplotype inspection of 16 affected animals indicated linkage to BTA5 in 12 animals, BTA18 in three animals, and linkage to both BTA5 and BTA18 in one animal. The bod1 locus was mapped to a 25 cM interval between DIK5237 and DIK5210 on BTA5 (Z(max) = 17.0, LOD(max) = 11.8), and bod2 was mapped to a 7 cM interval between DIK5411 and INRA038 on BTA18 (Z(max) = 13.0, LOD(max) = 4.0). This study demonstrated that the independent involvement of loss of function mutations in two loci is likely responsible for this genetic heterogeneity.

Animals↗
PubMed2001

Crystallization and preliminary X-ray characterization of rat liver acyl-CoA oxidase.

A recombinant form of the flavoenzyme acyl-CoA oxidase from rat liver has been crystallized by the hanging-drop vapour-diffusion technique using PEG 20 000 as a precipitating agent. The crystals grew as yellow prisms, with unit-cell parameters a = 71.05, b = 87.29, c = 213.05 A, alpha = beta = gamma = 90 degrees. The crystals exhibit the symmetry of space group P2(1)2(1)2(1) and are most likely to contain a dimer in the asymmetric unit, with a V(M) value of 2.21 A(3) Da(-1). The crystals diffract to a resolution of 2.5 A at beamline BL6A of the Photon Factory. Two heavy-atom derivatives have been identified.

Acyl-CoA Oxidase↗
PubMed2001

Massive large bowel resection decreases bone strength and magnesium content but not calcium content of the femur in rats.

We examined the effects of massive large bowel resection (cecocolonectomy) on calcium and magnesium absorption and bone characteristics in rats. Male Sprague-Dawley rats were divided into two groups: sham-operated and cecocolonectomized rats. The rats were fed a sucrose-based diet containing casein at 250 g/kg diet for 10 d after a 9- to 10-d postoperative recovery period. Apparent magnesium absorption but not calcium absorption was lower in the resection group than in the sham group. There was a tendency of lower serum magnesium concentration (P = 0.070) but not calcium concentration (P = 0.418) in the resection group compared with the sham group. The maximum breaking force and magnesium content but not the calcium content of the femur were lower in the resection group than in the sham group. These results suggest that massive large bowel resection influences magnesium kinetics and decreases bone strength through reduction of the magnesium content of the femur in rats. Femoral breaking force was positively correlated (r = 0.617, P = 0.011) with only the magnesium content. We conclude that the changes in magnesium kinetics caused by cecocolonectomy could contribute to the fragility of bone.

Animals↗
PubMed2001

Why the all-electron full-potential approach is suitable for calculations on fullerenes and nanotubes?

Already 30 years have passed since the first prediction of C60 by Professor Osawa. A family of cage-type fullerenes and carbon nanotubes were experimentally found as the third form of carbon molecules in the 1980s. After this discovery, much research has been conducted experimentally and theoretically on these new materials. The all-electron full-potential approach is important for fully understanding the quantum mechanical behavior of the fullerenes and related molecules. We show some results of band calculations and ab initio molecular dynamics.

Carbon↗
PubMed2001

On the ligands in charge-transfer complexes of porcine kidney flavoenzyme D-amino acid oxidase in three redox states: a resonance Raman study.

To investigate the structural modulation of ligands and their interaction in the active-site nanospace when they form charge-transfer (CT) complexes with D-amino acid oxidase (DAO) in three redox states, we compared Raman bands of the ligands in complex with DAO with those of ligands free in solution. Isotope-labeled ligands were synthesized for assignments of observed bands. The COO(-) stretching of ligands observed around, 1,370 cm(-1) downshifted by about 17 cm(-1) upon complexation with oxidized, semiquinoid and reduced DAO, except for the case of reduced DAO-N-methylisonicotinate complex (8 cm(-1) downward shift); the interaction mode of the carboxylate group with the guanidino group of Arg283 and the hydroxy moiety of Tyr228 of DAO is similar in the three redox states. The C=N stretching mode (1,704 cm(-1)) of Delta(1)-piperideine-2-carboxylate (D1PC) downshifted to 1,675 and 1,681 cm(-1) upon complexation with reduced and semiquinoid DAO, respectively. The downward shifts indicate that the C=N bond is weakened upon the complexation. This is probably due mainly to charge-transfer (CT) interaction between D1PC and semiquinoid or reduced flavin, i.e., the partial electron donation from the highest occupied molecular orbital (HOMO) of reduced flavin or a singly occupied molecular orbital (SOMO) of semiquinoid flavin to the lowest unoccupied molecular orbital (LUMO), an antibonding orbital, of D1PC. This speculation was supported by the finding that the magnitude of the shift is smaller by 5 cm(-1) (observed at 1,680 cm(-1)) in the case of reduced DAO reconstituted with 7,8-Cl(2)-FAD, whose reduced form has lower electron-donating ability than natural reduced FAD. The amount of electron flow was estimated by applying the theory of Friedrich and Person [(1966) J. Chem. Phys. 44, 2166-2170] to these complexes; the amounts of charge transfer from reduced FAD and reduced 7,8-Cl(2)-FAD to D1PC were estimated to be about 10 and 8% of one electron, respectively, in the CT complexes of reduced DAO with D1PC.

Animals↗
PubMed2000

The cecum and dietary short-chain fructooligosaccharides are involved in preventing postgastrectomy anemia in rats.

Dietary short-chain fructooligosaccharides (Sc-FOS) stimulate absorption of calcium and magnesium in the large intestine of rats. In this study, we examined whether Sc-FOS stimulate iron absorption in the large intestine by monitoring recovery from anemia in gastrectomized rats, with or without cecectomy. The rats were divided into four groups, i.e., sham-operated (Sham), gastrectomized only (GX), cecectomized only (CX) and both gastrectomized and cecectomized (GCX). Half of the rats in each group were fed a control diet (AIN-93G) and the other half were fed a Sc-FOS-containing diet (75 g/kg diet) for 28 d. Hematocrit (Ht) and hemoglobin concentration (Hb) were measured at the start, and on d 14 and 28 after the start of feeding. On the final day of the study, total blood was collected. Gastrectomy significantly decreased Ht and Hb, but cecectomy did not influence these variables. Dietary Sc-FOS prevented the decrease in Ht and Hb significantly. In the gastrectomized rats, the effectiveness of Sc-FOS in preventing postgastrectomy anemia was significantly diminished by cecectomy. These results suggest that the effect of Sc-FOS in increasing absorption of iron in gastrectomized rats takes place in part in the cecum. The cecum plays an important role in the mechanism by which Sc-FOS prevent postgastrectomy anemia.

Analysis of Variance↗
PubMed2000

Three-dimensional structure of the purple intermediate of porcine kidney D-amino acid oxidase. Optimization of the oxidative half-reaction through alignment of the product with reduced flavin.

The three-dimensional structure of the purple intermediate of porcine kidney D-amino acid oxidase (DAO) was solved by cryo-X-ray crystallography; the purple intermediate is known to comprise a complex between the dehydrogenated product, an imino acid, and the reduced form of DAO. The crystalline purple intermediate was obtained by anaerobically soaking crystals of oxidized DAO in a buffer containing excess D-proline as the substrate. The dehydrogenated product, delta(1)-pyrrolidine-2-carboxylate (DPC), is found sandwiched between the phenol ring of Tyr 224 and the planar reduced flavin ring. The cationic protonated imino nitrogen is within hydrogen-bonding distance of the backbone carbonyl oxygen of Gly 313. The carboxyl group of DPC is recognized by the Arg 283 guanidino and Tyr 228 hydroxyl groups through ion-pairing and hydrogen-bonding, respectively. The (+)HN=C double bond of DPC overlaps the N(5)-C(4a) bond of reduced flavin. The electrostatic effect of the cationic nitrogen of DPC is suggested to shift the resonance hybridization of anionic reduced flavin toward a canonical form with a negative charge at C(4a), thereby augmenting the electron density at C(4a), from which electrons are transferred to molecular oxygen during reoxidation of reduced flavin. The reactivity of reduced flavin in the purple intermediate, therefore, is enhanced through the alignment of DPC with respect to reduced flavin.

Animals↗
PubMed2000

Substrate recognition and activation mechanism of D-amino acid oxidase: a study using substrate analogs.

We investigated the mechanism of recognition and activation of substrate by D-amino acid oxidase (DAO) by thermodynamical and spectrophotometric methods using zwitterionic ligands [N-methylisonicotinate (NMIN), trigonelline, and homarine] and monoanionic ligands as model compounds of the substrate and the product. In terms of the charge within the substrate D-amino acid, monoanionic (e.g., benzoate), zwitterionic (e.g., NMIN), and dianionic (e.g., terephthalate) ligands are thought to be good models for neutral, basic, and acidic amino acids, respectively, because when a substrate binds to DAO, as previously reported, the a-ammonium group (-NH(3)(+)) probably loses a proton to become neutral (-NH(2)) before the oxidation. Zwitterionic ligands can also be good model compounds of product in the purple complex (the complex of reduced DAO with the product imino acid), because the imino nitrogen of the imino acid is in a protonated cationic form. We also discuss electrostatic interaction, steric effect, and charge-transfer interaction as factors which affect the affinity of substrate/ligand for DAO. Monoanionic ligands have high affinity for neutral forms of oxidized and semiquinoid DAO, while zwitterionic ligands have high affinity for anionic forms of oxidized, semiquinoid, and reduced DAO; this difference was explained by the electrostatic interaction in the active site. The low affinity of homarine (N-methylpicolinate) for oxidized DAO, as in the case of o-methylbenzoate, is due to steric hindrance: one of the ortho carbons of benzoate is near the phenol carbons of Tyr228 and the other ortho carbon is near the carbonyl oxygen of Gly313. The correlation of the affinity of meta- and para-substituted benzoates for oxidized DAO with their Hammet's s values are explained by the HOMO-LUMO interaction between the phenol group of Tyr224 and the benzene ring of benzoate derivative. The pK(a) of neutral flavin [N(3)-H of oxidized flavin, N(5)-H of semiquinoid flavin, and N(1)-H of reduced flavin] decreases by its binding to the apoenzyme. The magnitude of the decrement is oxidized flavin < semiquinoid flavin < reduced flavin. The largest factor in the substantially low pK(a) of reduced flavin in DAO is probably the steric hindrance between the hydrogen atom of H-N(1)(flavin) and the hydrogen atom of H-N of Gly315, which becomes significant when a hydrogen is bound to N(1) of flavin.

Alkaloids↗
PubMed2000

A unique junctional palindromic sequence in mitochondrial DNA from a patient with progressive external ophthalmoplegia.

A polymerase chain reaction (PCR) based procedure was modified to determine the deletion of mitochondrial DNA (mtDNA). The protocol consists of coamplification both of deleted and wild-type segments of mtDNA using a long PCR technique; evaluation of the deleted portion within the amplified DNA segments by restriction enzyme digestion followed by densitometrical analysis; and direct subcloning into a plasmid vector for DNA sequencing. The procedure revealed a 5.3 kb deletion of mtDNA in the biopsied muscle tissue obtained from a patient clinically diagnosed with progressive external ophthalmoplegia. The 5' and 3' sequences at both sides of the breakpoint comprise a 17 bp palindrome and 5 bp tandem repeats, suggesting that the deletion might occur through slipped mispairing and other novel mechanisms. This improved procedure has the potential to detect deletions occurring in the entire length of mtDNA, and mighty be useful for clinical screening of progressive external ophthalmoplegia.

DNA, Mitochondrial↗
PubMed2000

A clinical study of oral tongue cancer.

Thirty-nine previously untreated patients with squamous cell carcinoma of the oral tongue treated with curative intent in our hospital from 1993 through 1998 are reviewed. Of these patients, those in the early stage (stages I and II) constituted 64%. The over all 5-year survival rate of all the patients was 60%. The 5-year survival rate of the patients with early stage cancers was unsatisfactory (stage I: 73%; II: 56%). This was thought to be related to the absence of elective neck dissection and the administration of chemotherapy in the patients with early stage cancer. We concluded that elective neck dissection for levels I, II and III is the first choice of treatment strategy for patients with stage II cancer. Our data indicate that chemotherapy in patients with early stage cancer was not beneficial and might have increased the risk of late lymph node metastasis in the clinically NO patients without neck dissection. There were 9 patients younger than 40 years of age and their survival rate at 5 years was 80%, which was better than that of the older patients. The treatment strategy for patients younger than 40 years of age was similar to that of older patients.

Adult↗
PubMed2000

Streptococcus anginosus in head and neck squamous cell carcinoma: implication in carcinogenesis.

It has been suggested that Helicobacter pylori (H. pylori) infection might be associated with not only gastric ulcers but also gastric malignancies. Recently, it was reported that the Streptococcus anginosus (S. anginosus) DNA sequence was found in DNA samples extracted from esophageal cancers. Because smoking and alcohol abuse are regarded as risk factors for both esophgeal cancer and head and neck cancer, infection of S. anginosus might be associated with carcinogenesis of head and neck cancer. To investgate the involvement of S. anginosus infection in head and neck cancer, we analyzed 217 DNA samples prepared from head and neck squamous cell carcinomas. We performed PCR analysis with S. anginosus-16S ribosomal DNA-specific primers, and Southern blot analysis. For detection of S. anginosus in the oral and pharyngeal cavities, we used oropharyngeal bacteriological culture and PCR analysis of gingival smears of the patients. By PCR analysis, the S. anginosus DNA sequence was found in 217 out of 217 (100%) DNA samples obtained from head and neck cancers. By Southern blot analysis, positive bands were detected in 41 out of 125 (33%) samples. We could find no S. anginosus colony in oropharyngeal bacteriological culture dishes of 53 patients with and without head and neck cancer. On the other hand, we found the S. anginosus DNA fragment in 8 out of 8 DNA samples obtained from gingival smears by PCR analysis. These data indicate that the upper aerodigestive environment of the patients permitting S. anginosus infection was implicated in the carcinogenesis of head and neck squamous cell carcinoma.

Adult↗
PubMed1999

Production of calves by transfer of nuclei from cultured somatic cells obtained from Japanese black bulls.

We investigated the possibility of producing calves from transferable bovine embryos obtained by nuclear transfer using somatic cell-derived cell lines. Muscle cells obtained from 2 Japanese Black bulls were dispersed in Hank's solution supplemented with collagenase Type-I. The separated muscle cells were cultured in Dulbecco's Modified Eagle's medium (D-MEM) supplemented with 10% fetal bovine serum (FBS) at 39 degrees C in an atmosphere of 5% CO2 in air. Cells were passaged at least 4 times, and for 5 d prior to nuclear transfer they (donor cells: karyoplasts) were cultured in D-MEM supplemented with 0.5% FBS (to induce quiescence) or 10% FBS. Recipient oocytes were produced by in vitro culture of bovine oocytes that were obtained at a slaughterhouse and then enucleated in modified phosphate buffered saline supplemented with cytochalasin B. Embryos were reconstructed by 3 protocols using karyoplasts cultured in the medium with 0.5% FBS. 1) Group A: recipient oocytes (cytoplasts; n = 157) were treated with Ca ionophore A 23187, ethanol and cycloheximide, and then a karyoplast was fused to an activated cytoplast. 2) Group B: karyoplasts were transferred to cytoplasts (n = 117), and the couplets were treated with electric stimulation and then Ca ionophore A 23187 and cycloheximide. 3) Group C: cytoplasts (n = 104) were cultured for a further 12 h before fusion, and then the couplets were treated with electric stimulation and cycloheximide. 4) Group D: in addition to the above 3 groups, karyoplasts cultured in the medium with 10% FBS were transferred to recipient cytoplasts (n = 137) and treated as in Protocol 2. Reconstructed embryos were cultured in modified CR1aa for 8 d, and the development of embryos was assessed. In total 73 blastocysts were obtained, and the frequency of development to the blastocyst stage in Group A (2.5%) was lower than that of Groups B, C and D (20.5, 18.3 and 19.0%, respectively; P < 0.01). Of these the sex of 21 blastocysts was determined by rapid Y-chromosome detection assay, and all were male, suggesting that nuclear replacement had been achieved successfully. When 26 blastocysts were transferred to 20 recipient cows, 8 of them became pregnant; 4 cows subsequently aborted about 60 d after embryo transfer while the remaining 4 cows calved. These results indicate that reconstructed embryos obtained by nuclear transfer of muscle cell-derived cell lines can develop to the blastocyst stage, and some are sufficiently competent to develop to term. Particularly important was the finding that special culture protocols for somatic cells prior to nuclear transfer were not necessary in our system.

Animals↗