PubMed Health⌕ Search

Biomedical subjects

I Inoue

Publications and source records attributed to I Inoue.

At least 19 recordsLinked to original sources
PubMed2006

Pathophysiological role of endothelin in ectopic ossification of human spinal ligaments induced by mechanical stress.

Ossification of the posterior longitudinal ligament (OPLL) of the spine is characterized by progressive ectopic bone formation in the spinal ligament. To identify the genes related to ossification affected by mechanical stress during OPLL, analyses using cDNA microarray were carried out using cultured human spinal ligament cells that had been subjected to uniaxial cyclic stretching. Samples were obtained from a total of 14 patients: seven cervical or thoracic OPLL patients and seven control patients. Spinal ligament cells derived from tissues of OPLL (OPLL cells) and control (non-OPLL cells) patients were subjected to uniaxial sinusoidal cyclic stretching (0.5 Hz, 20% stretch) for various time periods (0-9 hours). cDNA microarrays revealed that ranges of distribution of both up- and downregulated genes evoked by cyclic stretching were significantly wider in OPLL cells than in non-OPLL cells. Increases in the mRNA expression of endothelin-1 (ET-1) as well as various marker genes related to ossification were also observed. mRNA expression of ET-1 and alkaline phosphatase was increased by mechanical stress in a time-dependent manner, while addition of ET-1 to static cultures of OPLL cells increased mRNA expression of alkaline phosphatase in a dose-dependent manner. During 9 hours of cyclic stretching, ET-1 release increased to about sixfold the amount observed in nonstretched cells. In non-OPLL cells, neither cyclic stretching nor ET-1 induced any increase in alkaline phosphatase expression. These results suggest that mechanical stress promotes the progression of ossification in OPLL cells through autocrine and/or paracrine mechanisms of ET-1.

Aged↗
PubMed2005

Evidence for natural selection in the HAVCR1 gene: high degree of amino-acid variability in the mucin domain of human HAVCR1 protein.

The family of genes encoding T-cell immunoglobulin and mucin-domain containing proteins (Tim), which are cell-surface molecules expressed in CD4(+) T helper cells, has important roles in the immune system. Here, we report three unusual patterns of genetic variation in the human hepatitis A virus cellular receptor 1 gene (HAVCR1) that are similar to patterns observed in major histocompatibility complex loci. First, levels of polymorphism in exon 4 of HAVCR1 were exceptionally high in humans (nucleotide diversity (pi)=45.45 x 10(-4)). Second, nonsynonymous substitutions and insertion/deletion variants were more frequent than synonymous substitutions in that exon (10 out of 12 variants). The rate of the mean number of nucleotide substitutions at nonsynonymous sites to synonymous sites at HAVCR1-exon 4 is >1 (P(A)/P(S)=1.92 and pi(A)/pi(S)=2.23). Third, levels of divergence among human, chimp, and gorilla sequences were unusually high in HAVCR1-exon 4 sequences. These features suggest that patterns of variation in HAVCR1 have been shaped by both positive and balancing natural selection in the course of primate evolution. Evidence that the effects of natural selection are largely restricted to the mucin domain of HAVCR1 suggests that this region may be of particular evolutionary and epidemiological interest.

Base Sequence↗
PubMed2005

Genome-wide linkage analysis of mandibular prognathism in Korean and Japanese patients.

The existence of familial aggregation of mandibular prognathism (MP) suggests that genetic components play an important role in its etiology. In this study, a genome-wide linkage analysis to identify loci susceptible to MP was conducted with 90 affected sibling-pairs in 42 families, comprised of 40 Korean sibling-pairs and 50 Japanese sibling-pairs. Two non-parametric linkage analyses, GENEHUNTER-PLUS and SIBPAL, were applied and detected nominal statistical significance of linkage to MP at chromosomes 1p36, 6q25, and 19p13.2. The best evidence of linkage was detected near D1S234 (maximum Z(lr) = 2.51, P = 0.0012). In addition, evidence of linkage was observed near D6S305 (maximum Z(lr) = 2.23, P = 0.025) and D19S884 (maximum Z(lr) = 1.93, P = 0.0089). Identification of the susceptible genes in the linkage regions will pave the way for insights into the molecular pathways that cause MP, especially overgrowth of the mandible, and may lead to the development of novel therapeutic tools.

Adolescent↗
PubMed2004

Local adaptation and population differentiation at the interleukin 13 and interleukin 4 loci.

A 25.6 kb region at chromosome 5q31, covering the entire human interleukin 13 (IL-13) and interleukin 4 (IL-4) genes, has been reported to be associated with bronchial asthma. We have examined nucleotide variations at this locus in African, European American, and Japanese populations, using 120 diallelic variants. A block of strong linkage disequilibrium (LD) (mid R:D'mid R:>0.7) spans a 10 kb region containing IL-4 in European American and Japanese populations, and is present but less clear in African samples. Two major haplotypes at IL-4 account for >80% of haplotypes in European Americans and Japanese. These haplotypes are common and quite diverged from each other and the ancestral haplotype, resulting in highly significant deviations from neutrality. F(ST) statistics show that European American and Japanese populations are unusually distinct at the IL-4 locus. The most common haplotype in the European American population is much less common in the Japanese population, and vice versa. This implies that natural selection has acted on IL-4 haplotypes differently in different populations. This selected variation at IL-4 may account for some genetic variance underlying susceptibility to asthma and other allergic diseases. The strong LD observed in the IL-4 region may allow more efficient disease-association studies using this locus.

Adaptation, Physiological↗
PubMed2003

Two cases with transient lipoprotein lipase (LPL) activity impairment: evidence for the possible involvement of an LPL inhibitor.

UNLABELLED: Two independent severe hypertriglyceridemic infants with transiently impaired lipoprotein lipase (LPL) activity were observed and the causes were explored. Both infants were female, born prematurely with low birth weight and developed hypertriglyceridemia (Fredrickson type V hyperlipidemia: high VLDL and low LDL/HDL) a few months after birth. While mass levels of their post-heparin plasma LPL and apoprotein C-II (apo C-II), a physiological activator of LPL, were normal, their post-heparin plasma LPL activities were remarkably impaired. Both of their mothers' post-heparin plasma LPL activities were slightly or moderately impaired as well, without a decrease in the LPL mass level. No mutations in the genes for LPL and apo C-II were detected in either patient. In an in vitro study with their serum at onset, we could not detect any distinct circulating inhibitors for LPL. There was no data supporting infection or autoimmune diseases, which might have an impact on LPL activity, during the follow-up period. Levels of their plasma triglyceride (TG) and total cholesterol (TC) were decreased quickly by a dietary intervention with medium-chain triglyceride (MCT) milk and kept normal even after stopping the intervention at around age 1 year. However, their low post-heparin LPL activity persisted and returned to normal at around age 2 years. Their low HDL cholesterol levels persisted even after recovery of the TG and TC levels, although lecithin:cholesterol acyltransferase (LCAT) and cholesterol-ester-transfer protein (CETP), two key enzymes of HDL metabolism, were normal throughout the course. The exact reasons why their post-heparin LPL activities were impaired for a certain period and why their HDL cholesterol levels have remained low are still unclear. CONCLUSION: Transiently impaired LPL activity with no defect in LPL enzyme induced severe hypertriglyceridemia in infants. The transient occurrence of inhibitor(s) for LPL was proposed.

Child↗
PubMed2002

Excitation-contraction coupling in isolated locomotor muscle fibres from the pelagic tunicate Doliolum which lack both sarcoplasmic reticulum and transverse tubular system.

In the locomotor muscle of the pelagic tunicate Doliolum, both the sarcoplasmic reticulum (SR) and the transverse-tubular (T-tubular) system are absent. The mechanism of excitation-contraction (E-C) coupling was studied in single muscle fibres enzymatically dissociated from Doliolum denticulatum. Whole cell voltage clamp experiments demonstrated an inward ionic current associated with membrane depolarisation. This current was blocked by 5 mmol.l(-1)Co(2+), a calcium current blocker, and suppressed by nifedipine, a specific L-type calcium channel blocker. An increase in the external K(+) concentration to 200 mmol.l(-1) (K(+)-depolarisation) induced a rise in the intracellular Ca(2+) level detected with fluo-3, a Ca(2+)-sensitive dye. However, when 5-10 mmol.l(-1) Co(2+) or 10-15 micro mol.l(-1) nifedipine was present in the external solution, K(+)-depolarisation did not induce a rise in the intracellular Ca(2+) level. Externally applied 5-10 mmol.l(-1) caffeine or 20 micro mol.l(-1) ryanodine had no effect on the intracellular Ca(2+) level. K(+)-depolarisation induced a rise in the intracellular Ca(2+) level in the presence of caffeine or ryanodine. Replacement of external Na(+) with Li(+) increased intracellular Ca(2+) levels. Our results show that contraction of the locomotor muscle in Doliolum is solely due to the influx of Ca(2+) through L-type calcium channels, and that relaxation is due to extrusion of Ca(2+) by Na(+)/Ca(2+) exchange across the sarcolemma.

Animals↗
PubMed2002

Association between gastric myoelectrical activity and intraluminal nitric oxide.

BACKGROUND: We have previously shown that the intraluminal concentration of NO in H. pylori-positive patients is significantly reduced compared to that in H. pylori-negative patients. AIM: The aim of this study was to evaluate the effect of H. pylori infection on gastric motor activity in relation to the level of NO and nitrite in the stomach in humans. METHODS: Thirty-two H. pylori-negative and 32 H. pylori-positive patients with dyspepsia were studied. Gastric myoelectrical activity was recorded for 24 h using surface electrogastrography. Intraluminal gas and juice were endoscopically collected from the stomach to determine NO and nitrite and nitrate (NOx) levels using a chemiluminescence system. RESULTS: The percentage of tachygastria in the morning preprandial state was significantly higher (P = 0.005) in H. pylori-positive than -negative patients. In H. pylori-negative patients, there was a significant positive correlation between NO levels and the percentage of bradygastria (r = 0.56, P = 0.001) and a significant negative correlation between NOx levels and the percentage of normal electrical activity (r = - 0.57, P=0.001) in the preprandial state. CONCLUSIONS: Gastric motor activity is associated with NO and NOx levels in the gastric lumen. H. pylori infection may play a role in the pathogenesis of abnormal gastric myoelectrical activity.

Adolescent↗
PubMed2001

Glycated high-density lipoprotein induces apoptosis of endothelial cells via a mitochondrial dysfunction.

Glycation of plasma proteins may contribute to an excess risk of developing atherosclerosis in patients with diabetes mellitus. Although it is believed that high-density lipoprotein (HDL) is nonenzymatically glycosylated at an increased level in diabetic individuals, little is known about a possible linkage between glycated HDL and endothelium dysfunction in diabetes. This study set out to clarify whether glucose-modified HDL affects the function of endothelial cells by examining the apoptosis of cultured human aortic endothelial cells (HAECs) exposed to a glycated-oxidized HDL (gly-ox-HDL) prepared in vitro. Incubation of HAECs with 100 microg/ml of gly-ox-HDL for 48 h showed apoptotic features, such as cell shrinkage, membrane blebbing, and concentration and fragmentation of the nucleus, and the degree of apoptosis was dose-dependent on the glucose used in the preparation of gly-ox-HDL. Stimulation of HAECs with gly-ox-HDL elicited a marked increase in caspase 3 activity and the expressions of active caspase 3 and caspase 9, whereas concomitant treatment with a caspase 3 inhibitor significantly blocked gly-ox-HDL-induced apoptosis of HAECs. The release of cytochrome c into cytosols markedly increased in HAECs during the treatment with gly-ox-HDL. The increased expressions of Bax and Bad were detected in HAECs incubated for 24 h with gly-ox-HDL, but gly-ox-HDL failed to interfere with the expression of Bcl-2 and Bcl-x. Moreover, in vitro experiments with HDL (gly-HDL) glycated in the presence of 2 mM EDTA and Cu(2+)-oxidized HDL suggested that the apoptotic effect of gly-ox-HDL on endothelial cells might be due to an additional oxidative modification of gly-HDL. Taken altogether, additional oxidation of HDL under hyperglycemic conditions may induce endothelial apoptosis through a mitochondrial dysfunction, following the deterioration of vascular function.

Aorta↗
PubMed2001

Genomewide-linkage and haplotype-association studies map intracranial aneurysm to chromosome 7q11.

Rupture of intracranial aneurysms (IAs) causes subarachnoid hemorrhage, a devastating condition with high morbidity and mortality. Angiographic and autopsy studies show that IA is a common disorder, with a prevalence of 3%-6%. Although IA has a substantial genetic component, little attention has been given to the genetic determinants. We report here a genomewide linkage study of IA in 104 Japanese affected sib pairs in which positive evidence of linkage on chromosomes 5q22-31 (maximum LOD score [MLS] 2.24), 7q11 (MLS 3.22), and 14q22 (MLS 2.31) were found. The best evidence of linkage is detected at D7S2472, in the vicinity of the elastin gene (ELN), a candidate gene for IA. Fourteen distinct single-nucleotide polymorphisms (SNPs) were identified in ELN, and no obvious allelic association between IA and each SNP was observed. The haplotype between the intron-20/intron-23 polymorphism of ELN is strongly associated with IA (P=3.81x10-6), and homozygous patients are at high risk (P=.002), with an odds ratio of 4.39. These findings suggest that a genetic locus for IA lies within or close to the ELN locus on chromosome 7.

3' Untranslated Regions↗
PubMed2001

On-chip culture system for observation of isolated individual cells.

To investigate the properties of isolated single cells with their environment, we developed the differential analysis method for single cells using an on-chip microculture system. The advantages of the system are, (i). continuous cultivation of a series of isolated single cells or a group of cells under contamination free conditions, (ii). continuous observation and comparison of those cells with 0.2 microm spatial resolution by a phase-contrast/fluorescent microscopy system with digital image processing. The core of the system is an n x n (n = 20-50) array of chambers, where each is 20-70 microm in diameter and 5-30 microm deep holes etched into a biotin-coated 0.17 mm thick glass slide. The biotin-coated glass slide is covered with the streptavidin coated cellulose semipermeable membrane, which is fixed on the surface of the glass slide by streptavidin-biotin attachment, separating those holes from the nutrient medium circulating through a 'cover chamber' above. A single cell or group of cells can thus be isolated from environment perfused with the same medium, and the medium in each chamber can be changed within the diffusion time (<1/30 s). In addition, the microchamber volumes of specific cells or cell groups can be controlled by the sizes of the chambers. By using this system we found that the length of isolated Escherichia coli increased at 0.06 microm min(-1) between cell divisions regardless of the chamber volume, and that the cell concentration reached 10(12) cells ml(-1) under contamination free conditions. The system is thus particularly useful for one cell level analysis because the direct descendants of single cells can be cultured and compared in the isolated microchambers, and the physical properties of the cells in each microchamber can be continuously observed and compared.

Buffers↗
PubMed2001

Mutations in the small heterodimer partner gene are associated with mild obesity in Japanese subjects.

Mutations in several genes encoding transcription factors of the hepatocyte nuclear factor (HNF) cascade are associated with maturity-onset diabetes of the young (MODY), a monogenic form of early-onset diabetes mellitus. The ability of the orphan nuclear receptor small heterodimer partner (SHP, NR0B2) to modulate the transcriptional activity of MODY1 protein, the nuclear receptor HNF-4alpha, suggested SHP as a candidate MODY gene. We screened 173 unrelated Japanese subjects with early-onset diabetes for mutations in this gene and found five different mutations (H53fsdel10, L98fsdel9insAC, R34X, A195S, and R213C) in 6 subjects as well as one apparent polymorphism (R216H), all present in the heterozygous state. Interestingly, all of the subjects with the mutations were mildly or moderately obese at onset of diabetes, and analysis of the lineages of these individuals indicated that the SHP mutations were associated with obesity rather than with diabetes. Therefore, an additional group of 101 unrelated nondiabetic subjects with early-onset obesity was screened for mutations in the SHP gene. Two of the previously observed mutations (R34X and A195S) and two additional mutations (R57W and G189E) were identified in 6 subjects, whereas no mutations were identified in 116 young nondiabetic lean controls (P = 0.0094). Functional studies of the mutant proteins show that the mutations result in the loss of SHP activity. These results suggest that genetic variation in the SHP gene contributes to increased body weight and reveal a pathway leading to this common metabolic disorder in Japanese.

Adolescent↗
PubMed2001

Analysis of single-cell differences by use of an on-chip microculture system and optical trapping.

A method is described for continuous observation of isolated single cells that enables genetically identical cells to be compared; it uses an on-chip microculture system and optical tweezers. Photolithography is used to construct microchambers with 5-microm-high walls made of thick photoresist (SU-8) on the surface of a glass slide. These microchambers are connected by a channel through which cells are transported, by means of optical tweezers, from a cultivation microchamber to an analysis microchamber, or from the analysis microchamber to a waste microchamber. The microchambers are covered with a semi-permeable membrane to separate them from nutrient medium circulating through a "cover chamber" above. Differential analysis of isolated direct descendants of single cells showed that this system could be used to compare genetically identical cells under contamination-free conditions. It should thus help in the clarification of heterogeneous phenomena, for example unequal cell division and cell differentiation.

Bacteria↗