Biomedical subjects

M Hori

Publications and source records attributed to M Hori.

At least 37 records · Page 2Linked to original sources

PubMed2004

Evolutionary history of coastal tiger beetles in Japan based on a comparative phylogeography of four species.

To reveal the phylogeographical patterns of four species of coastal tiger beetles in Japan (Lophyridia angulata, Abroscelis anchoralis, Cicindela lewisii and Chaetodera laetescripta), we conducted phylogenetic and nested clade analysis (NCA) using the mitochondrial DNA sequences of two loci (COI and 16S rRNA), with specimens sampled from Japan and neighbouring countries. Abroscelis anchoralis and L. angulata have similar disjunct distributions in Japan. The NCA indicated past fragmentation involving three isolated areas of A. anchoralis. In contrast, local populations of L. angulata in Japan shared the same haplotype, indicating recent vicariance. Co-occurrence of haplotypes from several divergent clades in Japanese populations of Ch. laetescripta suggested ancient vicariance and subsequent intermixing of local populations. The tree topology of C. lewisii, with shallow branches and little geographical segregation of haplotypes between Japan and Korea or within Japan, suggested that the Japanese population was segregated from the Korean population only recently. Restricted gene flow, with isolation by distance, was inferred for various geographical associations of haplotypes for coastal tiger beetles in the NCA. Based on these phylogeographical patterns, coupled with a molecular clock approach, the evolutionary history of four species of coastal tiger beetles was deduced, with the additional consideration of the competitive relationships among those species. We also discuss the conservation of highly localized A. anchoralis populations in Japan, using the concept of evolutionarily significant units.

Animals↗

PubMed2003

Laparoscopic lymph node dissection for gastric cancer with intraoperative navigation using three-dimensional angio computed tomography images reconstructed as laparoscopic view.

BACKGROUND: Laparoscopic extended lymph node dissection for gastric cancer is difficult to perform because it requires dissection with preservation of vessels. Therefore, an intraoperative navigation system for the angioarchitecture would be helpful. Recent enhanced volume-rendering computed tomography (CT) can produce clear intraluminal three-dimensional (3D) images. This advanced radiological technology can provide 3D angiographic images reconstructed in the same view as would be observed from a laparoscope inserted into the abdominal cavity. We report our experience with laparoscopic gastrectomy with radical lymph node dissection using this advanced radiological technology. METHODS: 3D CT angiographic images from the celiac axis to the proper hepatic artery were reconstructed in two ways preoperatively. The first was only 3D angiographic images that were reconstructed as the laparoscopic view (LapView 3D CT angiography). The second was LapView 3D CT angiography with images of the body of the pancreas, which was more useful for intraoperative navigation in comprehensing anatomy. Two monitors were placed over the shoulder of the patient during surgery. One monitor, which was controlled by the image mixer, projected the laparoscopic images with picture in picture of 3D CT angiographic images. The surgeon performed the surgery with reference to this monitor during lymph node dissection. RESULTS: 3D angiographic CT clearly showed all vessels of interest in laparoscopic lymph node dissection for gastric cancer in 10 cases. The anatomy of vessels appeared as if looking beyond visible surface. LapView 3D CT angiography was useful for laparoscopic navigation surgery.

Adult↗

PubMed2003

Ectopically expressed PDX-1 in liver initiates endocrine and exocrine pancreas differentiation but causes dysmorphogenesis.

To date, the potency of pancreatic and duodenal homeobox gene 1 (PDX-1) in inducing differentiation into insulin-producing cells has been demonstrated in some cells and tissues. In order to carry out efficient screening of somatic tissues and cells that can transdifferentiate into beta-cell-like cells in response to PDX-1, we generated CAG-CAT-PDX1 transgenic mice carrying a transgene cassette composed of the chicken beta-actin gene (CAG) promoter and a floxed stuffer DNA sequence (CAT) linked to PDX-1 cDNA. When the mice were crossed with Alb-Cre mice, which express the Cre recombinase driven by the rat albumin gene promoter, PDX-1 was expressed in more than 50% of hepatocytes and cholangiocytes. The PDX-1 (+) livers expressed a variety of endocrine hormone genes such as insulin, glucagon, somatostatin, and pancreatic polypeptide. In addition, they expressed exocrine genes such as elastase-1 and chymotrypsinogen 1B. However, the mice exhibited marked jaundice due to conjugated hyperbilirubinemia, and the liver tissue displayed abnormal lobe structures and multiple cystic lesions. Thus, the in vivo ectopic expression of PDX-1 in albumin-producing cells was able to initiate but not complete the differentiation of liver cells into pancreatic cells. The conditional PDX-1 transgenic mouse system developed in this study appeared to be useful for efficient screening of PDX-1 responsive somatic tissues and cells.

Animals↗

PubMed2003

Mechanical compression of the extracranial vertebral artery during neck rotation.

Using duplex ultrasonography (US), the authors showed compression of the extracranial vertebral artery (ECVA) during neck rotation in 5.0% of 1,108 patients. Age (per 10-year increase, OR 0.80, 95% CI 0.67 to 0.96), vessel diameters (per 0.5-mm diameter increase, OR 0.63, 95% CI 0.51 to 0.79), and symptoms upon neck rotation (OR 4.01, 95% CI 1.35 to 11.9) were associated with vessel compression. In one case, SPECT revealed decreased cerebral perfusion of the hindbrain during rotation. ECVA US is useful in identifying vessel compression, especially in patients with symptoms on neck rotation.

Aged↗

PubMed2003

Direct measurement of transition frequencies in isolated pHe+ atoms, and new CPT-violation limits on the antiproton charge and mass.

A radio frequency quadrupole decelerator and achromatic momentum analyzer were used to decelerate antiprotons and produce p4He+ and p3He+ atoms in ultra-low-density targets, where collision-induced shifts of the atomic transition frequencies were negligible. The frequencies at near-vacuo conditions were measured by laser spectroscopy to fractional precisions of (6-19) x 10(-8). By comparing these with QED calculations and the antiproton cyclotron frequency, we set a new limit of 1 x 10(-8) on possible differences between the antiproton and proton charges and masses.

Journal Article↗

PubMed2003

Review article: inflammation-related promotion of gastrointestinal carcinogenesis--a perigenetic pathway.

Chronic inflammation has been reported to accelerate neoplasmas in gastrointestinal tract. Certain bacteria including Helicobacter pylori directly interact with host cells, induce proinflammatory cytokines and stimulate production of free radicals. Free radicals cause mutations in target cells so that neoplastic clones are established. Accumulation of such genetic alterations may cause malignant transformation of some established clones. In addition, inflammatory alterations may promote growth, expansion and invasion of gastrointestinal epithelial cells. The latter changes caused by inflammation may occur even without further genetic mutations or epigenetic alterations, and therefore may be categorized as 'perigenetic alterations' of neoplastic cells. For an example, tumour necrosis factor alpha (TNF-alpha) plays pivotal roles not only in the reduction but also in the growth, invasion and metastases of certain neoplasmas. Our studies show that TNF-alpha increases intracellular radical production, degradates E-cadherin / beta-catenin complex and promotes dispersion and migration in epithelial cells transformed with an activated src oncogene (v-src). These data indicate that an inflammatory cytokine induces the malignant potential of src-activated neoplastic cells. Interestingly, TNF-alpha also induced these phenotypic changes in nonmutated cells whose c-Src was activated by TGF-alpha, suggesting that the invasive properties of the cell were not necessarily related to gene mutation. Furthermore, certain radical scavengers suppressed the invasive phenotype of the cells. These results indicate that perigenetic alterations are an important target of pharmacological intervention of carcinogenesis.

Cell Communication↗

PubMed2003

Strong static magnetic field and the induction of mutations through elevated production of reactive oxygen species in Escherichia coli soxR.

PURPOSE: Although strong static magnetic fields (SMF) are supposed to have the potential to affect biological systems, the effects have not been evaluated sufficiently. Experiments should be performed with a powerful SMF-generating apparatus to evaluate the biological effects of SMF. MATERIALS AND METHODS: An Escherichia coli mutation assay was used to assess the mutagenic effects of strong SMF. Various mutant strains of E. coli were exposed to up to 9 Tesla (T) for 24 h and the frequencies of rifampicin-resistant mutations were then determined. The expression of the soxS::lacZ fusion gene was assessed by measurement of beta-galactosidase activity. RESULTS: The results for survival or mutation were obtained with wild-type E. coli strain GC4468 and its derivatives defective in DNA repair enzymes or redox-regulating enzymes were all negative. On the other hand, the mutation frequency was significantly increased by the SMF exposure in soxR and sodAsodB mutants, which are defective in defence mechanisms against oxidative stress. Furthermore, the expression of superoxide-inducible soxS::lacZ fusion gene was stimulated 1.4- and 1.8-fold in E. coli when exposed to 5 and 9 T, respectively. CONCLUSIONS: These results indicate that strong SMF induce mutations through elevated production of intracellular superoxide radicals in E. coli.

Bacterial Proteins↗

PubMed2003

Impaired cardiac response to exercise in post-menopausal women: relationship with peripheral vascular function.

Endothelial dysfunction has been demonstrated in post-menopausal women. To assess the relationship between peripheral vascular reserve and cardiac function during exercise in post-menopausal women, 91 subjects, who had no ischaemic findings on myocardial SPECT, were assigned to four groups: pre-menopausal women (n=13), post-menopausal women (n=33), younger men aged < or =50 years (n=10), and older men aged >50 years (n=35). First-pass radionuclide angiography was performed before and during bicycle exercise to calculate ejection fraction (EF) and peripheral vascular resistance (VR). There were no differences in haemodynamic variables among the groups at baseline. The per cent increase in EF=(exercise EF - resting EF)x100/resting EF, and the per cent decrease in VR=(resting VR - exercise VR)x100/resting VR were depressed in the post-menopausal women (0.4+/-2% and 35+/-3%, respectively) compared to the pre-menopausal women (10+/-3% and 47+/-3%, respectively; P<0.05 each). Although the age dependent impairment is thought to cause this depression, neither the per cent increase in EF nor the per cent decrease in VR in the older men was significantly different from that in the younger men. Post-menopausal women exhibited depressed cardiac function during exercise, which may be related to the impairment of peripheral vascular function after menopause.

Adult↗

PubMed2003

Variation during the week in the incidence of acute myocardial infarction: increased risk for Japanese women on Saturdays.

BACKGROUND: Variations in the incidence of acute myocardial infarction during the week may differ between and within communities, according to lifestyle. OBJECTIVE: To identify potential triggering factors for acute myocardial infarction by examining variations in incidence in the days of the week within the Osaka area of Japan. PATIENTS: Of 2511 consecutive patients in this region who were admitted to hospital for acute myocardial infarction between April 1998 and March 2001 and consented to take part, 2400 who had a definitely identified time of onset were enrolled. RESULTS: For this group as a whole, no significant difference in incidence was noted between days of the week. However, in subgroup analyses women were shown to have significant variation through the week, peaking on Saturday with a 39% increase in relative risk (p = 0.037); working subjects showed a peak on Monday, with a 26% increase in relative risk (p = 0.038). Stratified analyses showed that in working men there was a prominent Monday peak in the onset of infarction, with a 30% increase in relative risk (p = 0.022), while in working women, there was no significant variation through the week. CONCLUSIONS: Earlier findings of a Monday peak linked to increased physical and mental occupational stress are confirmed. There is also an increase in uncertain risk factors on Saturdays for Japanese women, possibly involving a stressful weekend burden for women. Confirmation of this finding in other communities may help identify triggers of acute myocardial infarction and be useful in prevention.

Adult↗

PubMed2002

Hyperfine structure of antiprotonic helium revealed by a laser-microwave-laser resonance method.

Using a newly developed laser-microwave-laser resonance method, we observed a pair of microwave transitions between hyperfine levels of the (n,L)=(37,35) state of antiprotonic helium. This experiment confirms the quadruplet hyperfine structure arising from the interaction of the antiproton orbital angular momentum, the electron spin and the antiproton spin as predicted by Bakalov and Korobov. The measured frequencies of nu(+)(HF)=12.895 96+/-0.000 34 GHz and nu(-)(HF)=12.924 67+/-0.000 29 GHz agree with recent theoretical calculations on a level of 6x10(-5).

Journal Article↗

PubMed2002

Association of (-)786T-C mutation of endothelial nitric oxide synthase gene with insulin resistance.

AIMS/HYPOTHESIS: Endothelial derived nitric oxide synthase ( eNOS) gene polymorphisms affect eNOS activity and are associated with abnormal vasomotility and impaired local blood flow. A decrease in local blood flow has been reported to cause insulin resistance. The aim of this study was to examine a possible association of two eNOS polymorphisms, Glu298Asp (G894T) in exon 7 and (-)786T-C mutation with insulin resistance. METHODS: Genotypes of both Glu298Asp and (-)786T-C mutation were examined by the PCR-RFLP method. Plasma nitrate and nitrite concentrations were also measured. RESULTS: The allele frequencies of both polymorphisms showed no considerable differences in 233 non-diabetic subjects and 301 patients with Type II (non-insulin-dependent) diabetes mellitus. Non-diabetic subjects with the (-)786C allele had (p<0.05) higher fasting plasma insulin and homeostasis model assessment of insulin resistance than those with the (-)786T/ (-)786T genotype. Diabetic subjects with (-)786C allele showed higher HbA(1c) than those with the (-)786T/(-)786T genotype. A euglycaemic hyperinsulinemic clamp study done on 71 of the 301 patients showed a lower glucose infusion rate in diabetic patients with the (-)786C allele than those without it. In diabetic patients with the (-)786C allele, plasma nitrate and nitrite concentrations were lower than in subjects without it (p=0.026). No differences were observed between mutant carriers of Glu298Asp and non-carriers among both non-diabetic subjects and Type II diabetic patients. CONCLUSIONS/INTERPRETATION: The (-)786T-C mutation of the eNOS gene is associated with insulin resistance in both Japanese non-diabetic subjects and Type II diabetic patients.

Adult↗

PubMed2002

Primary populations of metastable antiprotonic (4)He and (3)He atoms.

Initial distributions of metastable antiprotonic (4)He and (3)He atoms over principal (n) and angular momentum (l) quantum numbers have been deduced using laser spectroscopy experiments. The regions n = 37-40 and n = 35-38 in the two atoms account for almost all of the observed fractions [(3.0 +/- 0.1)% and (2.4 +/- 0.1)%] of antiprotons captured into metastable states.

Journal Article↗

PubMed2002

Electron cooling of high-energy protons in a multiring trap with a tank circuit monitoring the electron-plasma oscillations.

Electron cooling of energetic protons in a multiring trap was investigated experimentally with a tank circuit monitoring electron-plasma oscillations in the trap. The energy of protons was determined by time-of-flight measurements. It is found that a simple model can explain the qualitative behavior of both electron and proton energy when the initial energy of protons is less than 2 keV. Monitoring the electron-plasma temperature with a tank circuit can be an effective tool when energetic particles are electron cooled in a multiring trap.

Journal Article↗

PubMed2002

A phosphodiesterase inhibitor, cilostazol, prevents the onset of silent brain infarction in Japanese subjects with Type II diabetes.

AIMS/HYPOTHESIS: This study aimed to evaluate the effect of a phosphodiesterase inhibitor, cilostazol, on the prevention of silent brain infarction in diabetic patients without symptoms of vascular events. METHODS: A total of 89 subjects were allocated at random to the cilostazol group ( n = 43) or the control group ( n = 46). RESULTS: After the study period (3.2 +/- 0.5 years), carotid intima-media thickness (IMT) (means +/- SD) had increased ( p < 0.01) by 0.18 +/- 0.19 mm in the control group. In the cilostazol group, intima-media thickness showed almost no change (-0.00 +/- 0.16 mm). In the control group, 2 out of 46 subjects showed symptomatic brain infarctions and 10 out of 34 subjects without infarct-like region assessed by standard brain MRI examination showed silent brain infarctions after the observation period. On the other hand, no subjects in the cilostazol group showed silent brain infarction or strokes during the study period. Both at the beginning and end of the study period, the number of infarct-like regions positively correlated with IMT ( r = 0.335, p < 0.001 or r = 0.347, p < 0.001 respectively). The progression of infarct-like regions was directly related to the increase in IMT during the study period ( r = 0.299, p = 0.004). CONCLUSION/INTERPRETATION: These data demonstrated that cilostazol could prevent the onset of silent brain infarction in Japanese subjects with Type II (non-insulin-dependent) diabetes mellitus. Also, an increase in intima-media thickness of the carotid artery wall could be able to predict the onset of silent brain infarction.

Aged↗

PubMed2002

Introduction of DNA enzyme for Egr-1 into tubulointerstitial fibroblasts by electroporation reduced interstitial alpha-smooth muscle actin expression and fibrosis in unilateral ureteral obstruction (UUO) rats.

The phenotypic alteration of interstitial fibroblasts into 'myofibroblasts', acquiring characteristics of both fibroblasts and smooth muscle cells is a key event in the formation of tubulointerstitial fibrosis. The up-regulation of the early growth response gene 1 (Egr-1) preceded the increased interstitial expression of alpha-smooth muscle actin (alphaSMA), a marker of phenotypic changes, in obstructed kidney, a model of interstitial fibrosis. To target Egr-1 expression in the interstitium of obstructed kidneys, we introduced a DNA enzyme for Egr-1 (ED5) or scrambled DNA (SCR) into interstitial fibroblasts by electroporation-mediated gene transfer. Northern blot analysis confirmed an increase in the cortical mRNA expression of Egr-1 in the obstructed kidneys from untreated or SCR-treated rats, while ED5 transfection blocked Egr-1 expression with a concomitant reduction in TGF-beta, alphaSMA and type I collagen mRNA expression. Consequently, ED5 inhibited interstitial fibrosis. In conclusion, electroporation-mediated retrograde gene transfer can be an ideal vehicle into interstitial fibroblasts, and molecular intervention of Egr-1 in the interstitium may become a new therapeutic strategy for interstitial fibrosis.

Actins↗

PubMed2002

A single nucleotide polymorphism of the low molecular mass polypeptide 7 gene influences the interferon response in patients with chronic hepatitis C.

Transporter associated with antigen processing (TAP) and low molecular mass polypeptides (LMP) play crucial roles in the human leukocyte antigen (HLA) class I-restricted antigen presenting systems. This study was performed to elucidate whether these antigen-presenting gene polymorphisms could influence the response to interferon (IFN) treatment in patients with chronic hepatitis C. Polymorphisms of TAP and LMP genes in 175 hepatitis C virus (HCV) patients were determined by polymerase chain reaction-restriction fragment length polymorphism. The frequencies of these genes were compared between sustained-responders (n=49) and nonresponders (n=126), classified by biochemical and virological responses to IFN. The distributions of TAP1*, TAP2*, and LMP2 genes between sustained-responders and nonresponders did not differ. However, LMP7-K gene frequency in sustained-responders was higher than that in nonresponders [odds ratio 2.3 (95% confidence interval 1.1-4.6); 16%vs 7.9%]. Multivariate analysis revealed that LMP7-K and HCV-RNA quantity were independent factors influencing the outcome of IFN therapy [4.5 (1.4-14); P=0.011, 0.40 (0.24-0.65); P=0.0003, respectively]. Furthermore, among patients with a low viral load (< or = 2.0 Meq/mL), the LMP7-K positive patients had an even higher ratio of sustained response compared to those without LMP7-K [5.9 (1.6-22); 82%vs 44%; P=0.0062]. These findings suggest that a single nucleotide polymorphism of LMP7 gene is one of the important host factors which independently influence the response to IFN in patients with chronic hepatitis C.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed2002

14 C-deoxyglucose imaging overestimates myocardial viability in subacute infarction of rats.

Clinical studies using 18F-fluorodeoxyglucose suggest that this tracer may overestimate myocardial viability. This study aimed to elucidate whether 2-deoxyglucose accurately indicates myocardial viability at the early phase of myocardial infarction. Autoradiography with 14C-deoxyglucose was performed in fasting rats whose left coronary artery was occluded for 60 min and then reperfused. 14C-deoxyglucose was injected 30 min after the reperfusion (acute; n=10) or 1 week later (subacute; n=9). Infarction and risk areas were identified by triphenyl tetrazolium chloride or haematoxylin-eosin staining and methylene blue, respectively. Immuno-histochemical staining using anti-glucose transporter 1 and 4 antibodies was performed. At the acute stage, the uptake of deoxyglucose was consistent with the grade of anti-glucose transporter 4 expression. At the subacute stage, the uptake of deoxyglucose in poorly viable myocardium (543.4+/-343.7%: normalized with the uptake at the right ventricle) as well as in the viable one (335.2+/-149.8%) in the risk area was significantly greater than that in the remote area (116.4+/-94.9%, P<0.01). Anti-glucose transporter 1 was expressed in the poorly viable area where inflammatory cells infiltrated. It is concluded that deoxyglucose uptake by inflammatory cells which express anti-glucose transporter 1 causes overestimation of myocardial viability at subacute stage.

Acute Disease↗

PubMed2002

Increased smooth muscle contractility of intestine in the genetic null of the endothelin ETB receptor: a rat model for long segment Hirschsprung's disease.

BACKGROUND AND AIMS: The endothelin ETB receptor null rat (ETB(-/-)R) has an intestinal segment without ganglia, and this rat is characterised by intestinal obstruction similar to that observed in human Hirschsprung's disease. In the present study, we have examined the myogenic mechanism responsible for obstruction in the ETB(-/-)R. RESULTS: The ETB(-/-)R had an enlarged belly and the average lifespan was 18.1 days. The bowel from the rectum to the lower part of the small ileum was constricted whereas the upper region was dilated with faecal stasis and thus presented as megaileum. The constricted muscle segments without ganglia had a greater increase in absolute force when stimulated by carbachol, high K+, and endothelin-1 compared with that of normal siblings. In contrast, in the dilated part with ganglia, the absolute contractile force due to these stimulants in the ETB(-/-)R was not different from that in the ETB(+/+)R. Such a functional hypertrophy of the musculature was observed in parts of the colon, caecum, and distal ileum without ganglia but not in the part of the proximal ileum and jejunum with ganglia. Morphological study demonstrated that the thickness of the circular and longitudinal muscle layers was greater in the constricted part of the intestine in the ETB(-/-)R, and these changes were associated with an increase in the number of smooth muscle cells. CONCLUSIONS: Our findings suggest that both increased contractility of smooth muscle and increased thickness of the intestinal muscular wall may contribute to the intestinal obstruction in the ETB(-/-)R.

Animals↗