Search PubMed⌕ Search

Biomedical subjects

S Yamaguchi

Publications and source records attributed to S Yamaguchi.

At least 793 records · Page 44Linked to original sources
PubMed1991

Urinary oligosaccharide excretion and severity of galactosialidosis and sialidosis.

Urinary oligosaccharides of galactosialidosis and sialidosis patients were investigated by the Bio-Gel P-4 column chromatography in order to delineate each clinical subtype biochemically. The levels of urinary oligosaccharides (nmol/mg creatinine) in late infantile-type galactosialidosis patients with early onset and severe clinical manifestations were 2.5 times the levels in juvenile/adult-type patients. Galactosyl oligosaccharides which had not been reported in the analysis of galactosialidosis urine were identified in the urine of patients of both subtypes. The structures of the urinary oligosaccharides in late infantile-type patients were the same as those in the juvenile/adult-type patients. The levels of urinary oligosaccharides in the infantile-type sialidosis patients were 3.5 times the levels in late-type patients who were less severely affected. The structures of oligosaccharides in the urine of infantile-type patients were the same as those in the urine of late-type patients, but more high-molecular weight sialyl oligosaccharides were excreted in the urine of infantile-type patients than in the urine of late-type patients. The structures of 7 different kinds of sialyl oligosaccharides that have not been previously reported were identified in the urine of both galactosialidosis and sialidosis patients. Sialidosis patients excreted relatively more sialyl oligosaccharides than did galactosialidosis patients.

Adolescent↗
PubMed1991

Second meiotic nondisjunction of the rearranged chromosome in a familial reciprocal 5/13 translocation.

We describe a 20-week-gestation male fetus with partial dup(5p) and proximal dup(13q), 47,XY,t(5;13)(p15;q21), + der(13)t(5;13)(p15;q21) mat. This finding is attributable to second meiotic nondisjunction of the rearranged chromosome in a maternal balanced reciprocal translocation. To the best of our knowledge, there have been only 3 previous reports of a similar error in the segregation of the rearranged chromosomes. For the first time evidence has been given that this unusual segregation is due to maternal second meiotic nondisjunction, using QFQ banding heteromorphisms. Second meiotic malsegregation should be taken into account in the consideration of reproductive problems in carriers of balanced translocations.

Abnormalities, Multiple↗
PubMed1991

Evidence for a structural mutation (347Ala to Thr) in a German family with 3-ketothiolase deficiency.

The molecular basis of 3-ketothiolase deficiency (3KTD) was examined in a 3KTD family. Immunochemical analyses showed that mitochondrial acetoacetyl-CoA thiolase (T2) biosynthesized in the patient's fibroblasts (GK06) was unstable and that the parents and brother were obligatory carriers of 3KTD. When sequencing the PCR-amplified patient's T2 cDNA, we noted a G to A replacement which caused 347Ala to Thr substitution of the mature T2 subunit. Transfection analysis revealed that this substitution resulted in an instability of the T2 protein. Analyses of the T2 cDNA and gene of the family indicated that the patient was a compound heterozygote; the allele that derived from the mother had a point mutation (347Ala to Thr) and the other allele from the father has a mutation which would abolish the T2 gene expression. This report is apparently the first definition of a mutant allele for 3KTD, at the gene level.

Acetyl-CoA C-Acyltransferase↗
PubMed1991

Cloning and structure of the mono- and diacylglycerol lipase-encoding gene from Penicillium camembertii U-150.

A gene (mdlA) encoding mono- and diacylglycerol lipase (MDGL) from Penicillium camembertii U-150 has been cloned using a 0.9-kb DNA fragment, generated by mixed oligodeoxyribonucleotide (oligo)-primed polymerase chain reaction (PCR), as a probe. Comparison of the nucleotide sequence of the gene and its cDNA clone, obtained by PCR, revealed the presence of two short introns (56 and 53 bp). Two transcription start points (tsp) were localized by primer extension analysis at 37 and 30 bp upstream from the ATG start codon and were preceded by the canonical TATAAA and CAAT sequences. The deduced amino acid (aa) sequence corresponds to 305 aa including a putative signal peptide of 26 aa. Despite significant differences in substrate specificity, the primary structure of the mature region shows homology (29% and 40%) to the triacylglycerol lipases from Mucor miehei and Humicola lanuginosa. Furthermore, the three residues presumed to form the catalytic site, serine, aspartic acid and histidine, are conserved. Primary structure comparisons of MDGL and triacylglycerol lipases are shown.

Amino Acid Sequence↗
PubMed1991

Amino acids responsible for flagellar shape are distributed in terminal regions of flagellin.

The shape of the flagellar filaments of the bacterium Salmonella typhimurium under ordinary conditions is a left-handed helix. In addition to the normal wild-type filament, non-helical (i.e. straight), right-handed helical (early), or circular (semi-coiled and coiled) filaments and filament with small amplitude (fl-type) have been found in mutants or in filaments reconstituted in vitro. We analysed wild-type flagellin and flagellins from 17 flagellar-shape mutants (6 with straight filaments, 6 with curly filaments, 4 with coiled filaments and 1 with fl-type filament) by amino acid sequencing to identify the mutational sites. All mutant flagellins except that of the fl-type filament had single mutations; the fl-type flagellin had two mutations in the molecule. The sites of these mutations were localized in alpha-helical segments of the terminal regions of flagellin. A possible mechanism of the polymorphism of the flagellar filament is discussed.

Amino Acid Sequence↗
PubMed1991

Effects of sodium 2-[5-(4-chlorophenyl)pentyl]-oxirane-2-carboxylate (POCA) on fatty acid oxidation in fibroblasts from patients with peroxisomal diseases.

The effects of sodium 2-[5-(4-chlorophenyl)pentyl]oxirane-2-carboxylate (POCA), a potent inhibitor of carnitine palmitoyltransferase I, on fatty acid oxidation were investigated using fibroblasts from control subjects and from patients with peroxisomal disorders. [1-14C]Palmitate oxidation was inhibited by 8% of the control value when 15 microM POCA was added to the medium. The inhibition by POCA was significantly (P less than 0.05) stronger in fibroblasts from patients with Zellweger syndrome or with neonatal adrenoleukodystrophy, in which peroxisomes and peroxisomal beta-oxidation enzymes were absent. However, the inhibition in fibroblasts from patients with X-linked adrenoleukodystrophy, in which a specific defect of peroxisomal lignoceroyl-CoA synthetase was speculated, was similar to that in the controls. [1-14C]Lignocerate oxidation was not influenced by the addition of POCA, in samples from the controls and from the patients. These results indicate that peroxisomes account for a small but demonstrable proportion of palmitate oxidation, and add new evidence to the concept that lignocerate is oxidized exclusively in the peroxisomes. Our findings also support the hypotheses that the activity of palmitoyl-CoA synthetase and the enzymes of beta-oxidation cycle in peroxisomes are normal in patients with X-linked adrenoleukodystrophy and that a specific defect of lignoceroyl-CoA synthetase is responsible for the accumulation of very long chain fatty acids in these patients.

Adrenoleukodystrophy↗
PubMed1991

High-intensity area in the deep white matter indicating hemodynamic compromise in internal carotid artery occlusive disorders.

We used positron emission tomography and magnetic resonance imaging to evaluate 16 patients with transient ischemic attacks or minor strokes and unilateral internal carotid occlusive disease, five with stenosis, and 11 with occlusion. Cerebral blood flow, cerebral metabolic rate of oxygen, oxygen extraction fraction, cerebral blood volume, and T2-weighted magnetic resonance images obtained at 1.5-T were analyzed. Irrespective of vascular disease, patients with a confluent high-intensity area in the middle centrum semiovale had substantially decreased cerebral blood flow and ratio of cerebral blood flow to blood volume in the middle cerebral artery distribution of the cortex, with a substantially increased oxygen extraction fraction. We concluded that the confluent high-intensity area in the deep white matter region indicates hemodynamic compromise in the affected hemisphere in internal carotid artery occlusive disease.

Aged↗
PubMed1991

Mass spectrometric analysis of metabolite excretion in five Japanese patients with the late-onset form of glutaric aciduria type II.

The variability of clinical and biochemical features in five Japanese patients with the late-onset form of glutaric aciduria type II (GAII) was studied using mass spectrometric procedures. The age at onset ranged from 5 months to five years, presenting acute episodes such as lethargy, hypotonia, hyperammonaemia, hypoglycaemia or Reye's syndrome-like illness, while one of the five cases was asymptomatic at 1 year of age. Organic acid analysis as oxime-trimethylsilyl derivatives by gas chromatography/mass spectrometry revealed the presence of several abnormalities characteristic of GAII in clinically asymptomatic conditions of three patients but not of the two others. Quantitative acylglycine analysis using a stable isotope dilution method and qualitative acylcarnitine analysis by fast atom bombardment mass spectrometry provided diagnostic information in all five patients, regardless of their clinical conditions. However, significant differences in the respective metabolite profiles as well as in their clinical pictures were noted. Although an increased excretion of both isovalerylglycine and isovalerylcarnitine was found in four patients, the fifth showed normal isovalerylglycine excretion during both the acute stage and in remission, despite the increased amount of isovalerylcarnitine in urine. From these results, it was suggested that the variations in clinical severity and metabolite excretion among GAII patients may be attributed not only to the residual enzyme activity at the defective site but also to differences in the capability to conjugate accumulated acyl-coenzyme A.

Acids↗
PubMed1991

Dose response study of N-nitrosodiethanolamine initiation of rat hepatocarcinogenesis.

Initiating activity of N-nitrosodiethanolamine (NDELA) for rat liver carcinogenesis was investigated using an 8-weeks bioassay system. Male F344 rats were initially treated with a single intraperitoneal injection of NDELA at one of five dose levels: 1,600, 800, 400, 200, or 100 mg/kg. Two weeks later, the rats were placed on 0.02% 2-acetylaminofluorene (2-AAF) or 0.05% phenobarbital (PB) containing diet for 6 weeks. All animals were subjected to 2/3 partial hepatectomy 4 weeks after the NDELA treatment, and killed at the end of the eighth week. NDELA itself exerted low toxicity in terms of body weight gain. Clear dose-dependent initiating activity of NDELA was observed in terms of development of glutathione S-transferase placental form (GST-P) positive liver cell foci, this being more apparent with PB promotion than with 2-AAF where the enhancing regimen itself caused multiple lesion development. Initiating potential of NDELA, however, was much lower than that observed for diethylnitrosamine in our previous work.

2-Acetylaminofluorene↗
PubMed1991

P300 generation by novel somatosensory stimuli.

Event-related potentials (ERPs) to task-relevant target and task-irrelevant novel stimuli were recorded in a somatosensory discrimination task. Subjects pressed a button to mechanical taps of the fifth finger (targets, P = 0.12), randomly interposed in sequences of taps to the second finger (standards, P = 0.76). Two types of infrequent novel stimuli were delivered; one was a mechanical tap to the third or fourth finger (tactile novels, P = 0.06), another was an electric shock at the wrist (shock novels, P = 0.06). Correctly detected targets generated a parietal maximal P300 (P3b, latency 335 msec). Shock novels generated a central maximal P300 with a shorter peak latency (298 msec) than the P3b. Tactile novels generated a P300 with a scalp distribution comparable to the shock novels. Unlike the P3b, P300 amplitude to both the shock and tactile novel stimuli habituated by 20-30% across the first several stimulus presentations. These results indicate that, similar to the auditory and visual modality, task-irrelevant novel somatosensory stimuli generate a novelty P300 ERP. Differences in scalp distribution, latency and habituation characteristics suggest that the novelty P300 may have contributions from intracranial generators independent from target P300 sources.

Adolescent↗
PubMed1991

Age effects on the P300 to novel somatosensory stimuli.

Event-related brain potentials (ERPs) to somatosensory task-relevant targets and task-irrelevant novel (tactile and shock) stimuli were studied in 30 subjects between the ages of 18 and 79. Target and novel P300 latencies increased linearly with age at comparable rates. P300 amplitudes and scalp topographies also changed with age. P300 amplitudes remained constant at frontal sites and decreased at central and parietal sites for both target and novel stimuli with increasing age. The current results extend the age-related novel P300 changes reported in the auditory and visual modalities to the somatosensory system. The age-related amplitude reduction at posterior scalp sites supports independent contributions of frontal and posterior association cortex to P300 generation.

Adolescent↗
PubMed1991

Coronal reconstruction images of glucose metabolism in Alzheimer's disease.

Coronal images of position emission tomography (PET) by 18F-labelled deoxyglucose reconstructed from interpolated scan in Alzheimer's disease clearly indicated suppression of glucose metabolism in the parietal lobe and lateral part of the temporal lobes, compared to normal controls. The medial part of the temporal lobes in Alzheimer's disease did show a mildly lower glucose metabolic rate than that in normal controls; therefore it is suggested that the parietal and lateral parts of the temporal lobes are primary affected regions in Alzheimer's disease, not the medial part of the temporal lobe, including the hippocampus.

Adult↗
PubMed1991

Basic properties of umami and effects on humans.

This is a review of the taste of umami substances, and some related findings. The data demonstrate that, though the taste of the common umami substances such as MSG and IMP is mainly caused by their anions, the effects of their cations, such as Na, should not be ignored. The effects of cations approach the taste thresholds of umami substances. Although the taste threshold of MSG was slightly lower than that of Na, the threshold of IMP was found to be controlled by Na. However, the degree of saltiness was less than 10% above the threshold of the equivalent weight of NaCl. It was also found that the taste of IMP was probably caused by glutamic acid in saliva, since IMP itself has no umami taste. That is, IMP enhances the umami taste of MSG. Finally, comparison of umami sensitivity of Japanese and Americans revealed no difference.

Cross-Cultural Comparison↗
PubMed1991

Induction of the interleukin-2 receptor (p55) by interferons.

The effect of human interferon (IFN) on the interleukin-2 receptor (IL-2R, p55) expression by peripheral blood mononuclear cells was investigated both in vitro and in vivo. IL-2R induction was assessed by the soluble IL-2R level in vitro and in vivo, which was measured by ELISA using two monoclonal antibodies to IL-2R(p55). Serum levels of sIL-2R increased significantly during IFN-alpha or IFN-beta therapy in 13 patients with chronic hepatitis B. When mononuclear cells were cultured with IFNs-alpha, -beta, or -gamma, the sIL-2R levels in the supernatant increased significantly. Dual flow cytometric analysis demonstrated that IL-2R was expressed on CD4+ and CD20+ mononuclear cells treated with IFN-alpha in vitro. CD4+ T cells and B cells may release sIL-2R when these cells are stimulated with IFN-alpha. RNA isolated from mononuclear cells treated with IFN-alpha contained increased levels of IL-2R-specific mRNA, as indicated by Northern blot analysis using an IL-2R-specific mRNA probe. These findings help to indicate how IFN plays a role in the regulation of the immune response, because IL-2R induction is known to be associated with lymphocyte activation.

CD4-Positive T-Lymphocytes↗
PubMed1991

Comparative significance in systolic ventricular interaction.

STUDY OBJECTIVE: The aim was to measure the systolic coupling between the ventricles and to determine the relative importance of ventricular interaction in the pressure development of each ventricle. DESIGN: Acute studies were done in dogs to measure the changes in right and left ventricular pressures (dPr, dPl) caused by sudden changes in left ventricular pressure (dPl') with release of an aortic constriction, and sudden changes in right ventricular pressure (dPr') with release of a pulmonary artery constriction, respectively. The instantaneous cross talk gain [dPr/dPl' (Klr) or dPl/dPr' (Krl)] was calculated during the ejection phase. The potential systolic pressure generated by the contralateral ventricle was evaluated as the cross talk gain multiplied by the contralateral systolic developed pressure. EXPERIMENTAL MATERIAL: Studies were done in eight random source dogs (12-18 kg), anaesthetised with sodium pentobarbitone. MEASUREMENTS AND MAIN RESULTS: The maximal Klr was lower than the maximal Krl, at 0.09 (SD 0.05) v 0.25 (0.06), and the mean Klr also was lower than the mean Krl, at 0.04 (0.02) v 0.10 (0.03), p less than 0.05. The potential right ventricular pressures developed by the left ventricle [maximum 10.3(5.6), mean 4.8(2.7) mm Hg] were not significantly different from the potential left ventricular pressures developed by the right ventricle [maximum 8.8(2.7), mean 3.4(0.7) mm Hg]. However, the ratio between the potential transmitted pressure and the measured developed pressure was greater in the right ventricle [maximum 39.0(21.1), mean 17.8(8.9)%] than in the left ventricle [maximum 11.1(7.1)%, p less than 0.05; mean 3.9(1.5)%, p less than 0.01]. This suggests that about 20-40% of the right ventricular systolic pressure may result from the left ventricle and about 4-10% of the left ventricular systolic pressure may result from right ventricle. CONCLUSIONS: Although the pressure coupling was greater in right to left ventricular interaction, right ventricular pressure generation may be more dependent on the left ventricle. Systolic ventricular interaction may be more important for right ventricular systolic function. Further, the parameters of right ventricular systolic function currently used may be considerably affected by the left ventricle.

Animals↗