PubMed Health⌕ Search

Biomedical subjects

J Goto

Publications and source records attributed to J Goto.

At least 19 recordsLinked to original sources
PubMed2006

Analysis of cadmium in food by multiple prompt gamma-ray spectroscopy.

The Cd concentration in food is a public concern related to the human health. In order to remove Cd-polluted food, the development and validation of a rapid and sensitive method of Cd analysis is required. By applying the multiple gamma-ray detection method to prompt gamma-ray analysis (PGA), the influence from nuclei which emit only one prompt gamma-ray at a time at every neutron capture reaction can be reduced, therefore the quantification limit of Cd is improved significantly. The limit of Cd contained in rice in the case of MPGA was evaluated, and under our proposed experimental conditions, it may be possible to quantify Cd content in rice to within 0.2 ppm in 10 min.

Cadmium↗
PubMed2004

Japanese SCA families with an unusual phenotype linked to a locus overlapping with SCA15 locus.

The authors identified two Japanese spinocerebellar ataxia (SCA) families characterized by postural and action tremor and a very slow progression rate. A genome-wide linkage analysis revealed linkage to chromosome 3p26.1-25.3 with the highest multipoint lod score at D3S3728 (Zmax = 3.31 at theta = 0.00). The candidate region was 14.7 cM flanked by D3S1620 and D3S3691, which was partly overlapping with the locus of SCA15 characterized by pure cerebellar ataxia. Despite the difference in phenotypes, there remains a possibility that the causative gene for these Japanese SCA is allelic to SCA15.

Adult↗
PubMed2002

Homozygous Machado-Joseph disease presenting as REM sleep behaviour disorder and prominent psychiatric symptoms.

A male patient carrying the homozygous gene for Machado-Joseph disease (MJD) presented at age 43 with sleep disturbances and psychiatric symptoms followed by ataxic speech and gait. A polysomnogram (PSG) showed decreased rates of sleep time and stage rapid eye movement (REM) and an increased rate of 'stage 1-REM with tonic EMG' (Tachibana et al., 1975); all compatible with REM sleep behaviour disorder (RBD). Molecular gene analysis at age 59 showed that the CAG repeat units in the MJD gene were 60 and 60, smaller than the reported lengths for homozygous MJD patients (63-70 and 66-72). In addition to sleep disturbances, in particular RBD, psychiatric symptoms may be important clinical features in both heterozygous and homozygous MJD.

Diagnosis, Differential↗
PubMed2001

Capillary gas chromatographic behaviour of tert.-hydroxylated steroids by trialkylsilylation.

Capillary gas chromatographic behaviour was studied for a variety of structurally different bile acids and sterols having one to two tert.-hydroxy groups, together with several sec.-hydroxy groups, at positions C-3, -5, -7, -12, -14, -17, -20, -24, and/or -25. The tert.-hydroxylated steroids were subjected to trimethylsilylation with hexamethyldisilazane/trimethylchlorosilane /pyridine and N,O-bis(trimethylsilyl)acetamide/N-trimethylsilylimidazole/trimethylchlorosilane, and dimethylethylsilylation with N,N,-dimethylethylsilylimidazole. The methylene unit values of the resulting trialkylsilylation products were used for determining their structures of partially and/or fully derivatised ethers. The reactivity of the trialkylsilylation of tert.-hydroxy groups was found to be significantly dependent not only on the derivatisation reagents and conditions used, but also on the position and steric factor of the tert.-hydroxy groups. The following general order of the decreasing reactivity of tert.-hydroxy groups in steroids by trialkylsilyl etherification was observed: 25>20, 24>5beta>17alpha>>14alpha.

Chromatography, Gas↗
PubMed2001

Heme oxygenase-1 inhibits atherogenesis in Watanabe heritable hyperlipidemic rabbits.

BACKGROUND: Heme oxygenase-1 (HO-1) is proposed to have a variety of adaptive responses against oxidative stress. To examine the function of HO-1 against atherogenesis in vivo, we observed the effects of HO-1 inhibition on atherosclerotic lesion formation in Watanabe heritable hyperlipidemic rabbits (WHHL). Methods and Results- During 4 weeks of a 1% cholesterol diet, intravenous injections of Sn-protoporphyrin IX to inhibit HO-1 (S group, n=10) and saline as a control (C group, n=10) were given to 3-month-old WHHL rabbits. The percentages of en face atherosclerotic lesion areas in total descending aorta by Sudan IV staining (EFA) and the ratio of intima to media in microscopic atherosclerotic lesions in the ascending aortas (I/M) were calculated. Two different quantitative methods revealed significantly greater atherosclerotic lesions in the S group than the C group (EFA, P<0.001; I/M, P<0.005). HO-1 expression in atherosclerotic lesions was confirmed by Northern blot and immunohistochemical analyses. The dominant cell types expressing HO-1 were macrophages and foam cells, in which oxidized phospholipids were also accumulated. HO inhibition increased plasma and tissue lipid peroxide levels without affecting plasma lipid co osition. CONCLUSIONS: These results suggest the possibilities that HO-1 has antiatherogenic properties in vivo and that the antiatherogenic properties of HO-1 are conducted through the prevention of lipid peroxidation.

Animals↗
PubMed2001

Single cell analysis of CAG repeat in brains of dentatorubral-pallidoluysian atrophy (DRPLA).

Somatic mosaicism of an expanded repeat is present in tissues of patients with triplet repeat diseases. Of the spinocerebellar ataxias associated with triplet repeat expansion, the most prominent heterogeneity of the expanded repeat is seen in dentatorubral-pallidoluysian atrophy (DRPLA). The common feature of this somatic mosaicism is the difference in the repeat numbers found in the cerebellum as compared to other tissues. The expanded allele in the cerebellum shows a smaller degree of expansion. We previously showed by microdissection analysis that the expanded allele in the granular layer in DRPLA cerebellum has less expansion than expanded alleles in the molecular layer and white matter. Whether this feature of lesser expansion in granule cells is common to other types of neurons is yet to be clarified. We used a newly developed excimer laser microdissection system to analyze somatic mosaicism in the brains of two patients, one with early- and another with late-onset DRPLA, and used single cell PCR to observe the cell-to-cell differences in repeat numbers. In the late onset patient, repeat expansion was more prominent in Purkinje cells than in granule cells, but less than that in the glial cells. In the early onset patient, repeat expansion in Purkinje cells was greater than in granule cells but did not differ from that in glial cells. These findings suggest that there is a difference in repeat expansion among neuronal subgroups and that the number of cell division cycles is not the only determinant of somatic mosaicism.

DNA Mutational Analysis↗
PubMed2001

The enantioselective immunoaffinity extraction of an optically active ibuprofen-modified peptide fragment.

Acyl glucuronides are known to produce the covalently bound protein adducts which may be the cause of hypersensitivity and toxic responses to acidic drugs. The structural analysis of the drug-protein adducts is therefore needed. From this point of view, we developed an enantioselective immunoaffinity extraction method, which employs an immobilized antibody to specifically isolate peptide fragments that have been modified with optically active ibuprofen. Rabbits were immunized with (S)-ibuprofen coupled to bovine serum albumin through a beta-alanine group. The elicited antibody strongly recognizes the asymmetric center and the isobutylphenyl moiety of (S)-ibuprofen and its conjugates but has a low affinity for their anti podes. A 0.5-mL aliquot of the immunosorbent (11.5 mg of IgG/mL gel) prepared by immobilization of the antibody was capable of retaining up to 1 microg of (S)-ibuprofen. When a mixture of substance P with (R)- and (S)-ibuprofen-modified substance P was loaded on the immunosorbent, the (S)-ibuprofen-modified substance P was selectively retained. The modified peptide was quantitatively recovered by elution with 10 mM ammonium acetate buffer (pH 5.0)/methanol (5:95, v/v). The proposed method would be useful for the structural characterization of optically active ibuprofen-modified human serum albumin.

Antibodies↗
PubMed2001

Age-dependent and tissue-specific CAG repeat instability occurs in mouse knock-in for a mutant Huntington's disease gene.

Huntington's disease (HD) is a neurodegenerative disorder characterized by the expansion of CAG repeats in exon 1 of the HD gene. To clarify the instability of expanded CAG repeats in HD patients, an HD model mouse has been generated by gene replacement with human exon 1 of the HD gene with expansion to 77 CAG repeats. Chimeric proteins composed of human mutated exon 1 and mouse huntingtin are expressed ubiquitously in brain and peripheral tissues. One or two CAG repeat expansion was found in litters from paternal transmission, whereas contraction of CAG repeat in litters was observed through maternal transmission. Elderly mice show greater CAG repeat instability than younger mice, and a unique case was observed of an expanded 97 CAG repeat mouse. Somatic CAG repeat instability is particularly pronounced in the liver, kidney, stomach, and brain but not in the cerebellum of 100-week-old mice. The same results of expanded CAG repeat instability as observed in this HD model mouse were confirmed in the human brain of HD patients. Glial fibrillary acidic protein (GFAP)-positive cells have been found to be increased in the substantia nigra (SN), globus pallidus (GP), and striatum (St) in the brains of 40-week-old affected mice, although without neuronal cell death. The CAG repeat instability and increase in GFAP-positive cells in this mouse model appear to mirror the abnormalities in HD patients. The HD model mouse may therefore have advantages for investigations of molecular mechanisms underlying instability of CAG repeats.

Age Factors↗
PubMed2001

Prevention of hepatitis C virus infection in a chimpanzee by vaccination and epitope mapping of antiserum directed against hypervariable region 1.

We previously reported on a chimpanzee immunized with both putative envelope glycoproteins (E1 and E2) of hepatitis C virus (HCV), strain HCV-N2, and synthetic peptides of hypervariable region 1 (HVR1) of a different isolate, HCV-#6. The chimpanzee showed complete protection against HCV-#6 infection only when the titer of anti-HVR1 increased, suggesting that an immune response to the HVR1 is more essential in protecting a chimpanzee from HCV infection than an immune response to E1 and E2. In this study, we immunized this chimpanzee with only synthetic HVR1 peptides after anti-E1 and anti-E2 antibody levels dropped and then rechallenged with 10 infectious chimpanzee doses of HCV. The immunized animal was protected, and neutralization of HCV with the antiserum from the protected animal was achieved by inoculating another chimpanzee with HCV preneutralized by this antiserum mixture. Epitope analysis of HVR1 by Pin-ELISA using this antiserum seemed to demonstrate that the antibody response was directed mainly against the C terminus of HVR1. Moreover, our results showed that, if a part of the sequences was conserved, a broad cross-reactivity of the antiserum could be observed, even if amino-acid sequences in this epitope were substituted for those of other HCV strains.

Journal Article↗
PubMed2001

Bile acid acyl adenylate: a possible intermediate to produce a protein-bound bile acid.

The non-enzymatic production of a protein-bound adduct by the action of the acyl adenylate of bile acids is described. On incubation of deoxycholyl adenylate with substance P in phosphate buffer, peptides covalently bound with one or two molecules of the bile acid were detected. The modified peptides were structurally characterized by time-of-flight mass spectrometry with matrix-assisted laser desorption/ionization (MALDI-TOFMS) in the post-source decay mode, and by liquid chromatography/electrospray ionization MS/MS. The deoxycholic acid was bound on substance P through the amino group at Arg-1 and/or Lys-3. The adenylate of cholic acid also produced the protein-bound bile acid on incubation with lysozyme, and the binding sites of the cholic acid appeared to be the lysine residues at 1, 33, 97 and 116. The results clearly suggest that bile acid adenylates in vivo may act as active intermediates to produce covalently bound bile acid adducts with peptides and proteins by nucleophilic displacement of the 5'-adenylic acid through the free amino groups.

Adenosine Monophosphate↗
PubMed2001

Resistance of primary cultured mouse hepatic tumor cells to cellular senescence despite expression of p16(Ink4a), p19(Arf), p53, and p21(Waf1/Cip1).

Primary cultured mouse hepatic cells become senescent within a short period, although rare cells form colonies from which continuously proliferating cell lines can be established. In contrast, hepatic tumor (HT) cells show little senescence and higher colony-forming capacity. To assess this difference, we investigated p16(Ink4a)/p19(Arf)/p53/p21(Waf1/Cip1) expression in primary normal and HT cells, together with cell lines established from both. In primary normal cells, p16(Ink4a)/p19(Arf) were expressed only in association with senescence and disappeared at later stages of colony formation. In contrast, primary HT cells showed sustained p16(Ink4a)/p19(Arf) expression from the beginning. No p16(Ink4a)/p19(Arf) alterations, such as deletion, mutations, or hypermethylation, were detected in the primary HT cells, although most cell lines derived from either normal or HT cell colonies lost p16(Ink4a) or p19(Arf) expression owing to hypermethylation or homozygous deletion of p16(Ink4a)/p19(Arf). On the other hand, primary normal and HT cells and most cell lines showed constitutively elevated expression of p53/p21(Waf1/Cip1), with a further increment after ultraviolet ir-radiation, indicating a functionally normal p53 pathway. These results indicate that primary HT cells are resistant to senescence despite retaining p16(Ink4a)/p19(Arf)/p53/p21(Waf1/Cip1) expression and that loss of p16(Ink4a)/p19(Arf) function is associated only with establishment of the cell lines.

Alkylating Agents↗
PubMed2001

The genomic structure and expression of MJD, the Machado-Joseph disease gene.

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder that is clinically characterized by cerebellar ataxia and various associated symptoms. The disease is caused by an unstable expansion of the CAG repeat in the MJD gene. This gene is mapped to chromosome 14q32.1. To determine its genomic structure, we constructed a contig composed of six cosmid clones and eight bacterial artificial chromosome (BAC) clones. It spans approximately 300kb and includes MJD. We also determined the complete sequence (175,330bp) of B445M7, a human BAC clone that contains MJD. The MJD gene was found to span 48,240bp and to contain 11 exons. Northern blot analysis showed that MJD mRNA is ubiquitously expressed in human tissues, and in at least four different sizes; namely, 1.4, 1.8, 4.5, and 7.5kb. These different mRNA species probably result from differential splicing and polyadenylation, as shown by sequences of the 21 independent cDNA clones isolated after the screening of four human cDNA libraries prepared from whole brain, caudate, retina, and testis. The sequences of these latter clones relative to the MJD gene in B445M7 indicate that there are three alternative splicing sites and eight polyadenylation signals in MJD that are used to generate the differently sized transcripts.

Alternative Splicing↗
PubMed2001

Enantioseparation of chiral amino acids as the N(O,S)-ethoxycarbonylated diastereomeric esters by achiral dual-capillary column gas chromatography.

The enantioseparation of 30 racemic amino acids in a single analysis is described for the determination of their absolute configurations. Two-phase extractive ethoxycarbonyl (EOC) reaction with ethyl chloroformate present in the dichloromethane phase was performed to recover amino acids from alkaline aqueous solutions. The resulting N(O,S)-EOC amino acids extracted into an organic solvent after acidification were reacted with a chiral alcohol such as (S)-(+)-3-methylbutan-2-ol, (S)-(+)-butan-2-ol and (S)-(+)-octan-2-ol for gas chromatographic analysis on achiral dual-capillary DB-5 and DB-17 columns of different polarities. Among the chiral reagents examined, (S)-(+)-3-methylbutan-2-ol provided the best diastereomeric structures in resolving all the racemic amino acids into their enantiomeric pairs with high resolution factors (1.2-8.0). Moreover, the temperature-programmed retention index (I) values measured on the two columns were characteristic of each enantiomer. Hence simple I matching with the reference values was useful in cross-checking for chemical identification and also chiral discrimination. When the present method was applied to a fermented dairy product (Yakult), D-alanine, D-aspartic acid, D-glutamic acid and D-proline were positively detected along with their respective L-forms in addition to glycine.

Amino Acids↗
PubMed2001

Studies on the mechanism of edematous changes at the endometrial stroma for implantation.

The endometrium undergoes edematous changes during the implantation period. Many factors may be involved in these biochemical reactions. We investigated the localization of inducible NO synthase (iNOS), interleukin-8 (IL-8), mast cell tryptase, neutrophil elastase, type III collagen, and CD44 in human endometrium. Immunohistochemical staining was performed by the labeled streptavidin-biotin method. iNOS was stained in the entire endometrial tissue from the midproliferative phase. The IL-8-positive cells, mast cells, and neutrophil elastase in the stroma increased toward the early to midsecretory phase. Type III collagen was arranged regularly in the stromal extracellular matrix during the proliferative phase; however, it was dissected during the secretory phase. CD44 was detected around stromal cells in the midsecretory phase. From these results, we propose the following mechanism. Initially, iNOS, expressed by the entire endometrial tissues from the midproliferative phase, catalyzes the production of NO. NO stimulates cells, supposed to be mast cells, to produce IL-8, which lets neutrophils migrate into the stroma. Neutrophils secrete elastase, which degrades type III collagen, generating spaces in the stroma. Hyaluronic acid adheres to CD44 around the stromal cells and retains water intermolecularly, finally forming the edematous matrix.

Adult↗
PubMed2001

Simultaneous detection of cholyl adenylate and coenzyme A thioester utilizing liquid chromatography/electrospray ionization mass spectrometry.

It has been proposed that acyl adenylate is first formed during activation of the carboxy group into the acyl CoA thioester, an intermediate in the formation of amino acid conjugates. Acyl CoA synthetases may be responsible for this acyl adenylate formation. Recently, we hypothesized the preferential formation of cholic acid adenylate, a major bile acid, preceding production of the corresponding CoA thioester in incubations with rat liver microsomal fractions. To verify this biosynthetic mechanism, monitoring of the incubation mixture of acyl adenylate together with both substrate and acyl CoA thioester is needed. We have developed a detection method for the simultaneous detection of these cholic acid derivatives utilizing liquid chromatography/electrospray ionization mass spectrometry. The CoA thioester of cholic acid forms a chelation complex with the divalent cations remaining on the silica gel packed into the analytical column. Both the addition of a chelating agent, such as EDTA, to the mobile phase and an adjustment of the mobile phase pH to a weak alkaline effectively removed such chelate formation, producing a sharp CoA thioester peak. For a simultaneous mass spectrometric analysis of cholic acid, the corresponding adenylate and CoA thioester, the combined use of a 300 A particle diameter ODS column and 20 mM ammonium acetate buffer (pH 9.0)/2-propanol/acetonitrile as the mobile phase have been proved to be preferable. To avoid any degradation of the chemically unstable adenylate produced in the incubation, we employed a direct injection of the sample onto a preconcentration column. The obtained results indicated a high sensitivity of this method.

Adenosine Monophosphate↗