Biomedical subjects

A Horii

Publications and source records attributed to A Horii.

At least 19 recordsLinked to original sources

PubMed2007

Quantitative evaluation of adhesion of lactobacilli isolated from human intestinal tissues to human colonic mucin using surface plasmon resonance (BIACORE assay).

AIMS: To isolate lactobacilli from the mucus layer of the human intestine and evaluate their adhesion abilities using a BIACORE assay. METHODS AND RESULTS: Thirty strains of lactobacilli were isolated from the mucus layer of normal human intestinal tissues using conventional plate culture. The strains were identified using homology comparisons of the 16S rDNA sequence to databases as Lactobacillus salivarius (26%), Lactobacillus fermentum (13%), Lactobacillus gasseri (10%), Lactobacillus paracasei (7%), Lactobacillus casei (3%), Lactobacillus mucosae (3%) and Lactobacillus plantarum (3%). Lactobacillus plantarum LA 318 shows the highest adhesion to human colonic mucin (HCM) using the BIACORE assay at 115.30 +/- 12.37 resonance unit (RU). The adhesion of cell wall surface proteins from strain LA 318 was significantly higher to HCM than to bovine serum albumin (BSA; P < 0.05). CONCLUSIONS: We isolated 30 strains of lactobacilli. Lactobacillus salivarius was the predominant species of lactobacilli isolated in this study. The adhesion of strain LA 318 isolated from human transverse colon to its mucin was shown. The adhesion could be mediated by lectin-like components on the bacterial cell surface. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first study where lactobacilli were isolated from human intestinal tissues and shown to adhere to HCM.

Bacterial Adhesion↗

PubMed2006

Genome-wide profiling of promoter methylation in human.

DNA methylation in the promoter region of a gene is associated with a loss of that gene's expression and plays an important role in gene silencing. The inactivation of tumor-suppressor genes by aberrant methylation in the promoter region is well recognized in carcinogenesis. However, there has been little study in this area when it comes to genome-wide profiling of the promoter methylation. Here, we developed a genome-wide profiling method called Microarray-based Integrated Analysis of Methylation by Isoschizomers to analyse the DNA methylation of promoter regions of 8091 human genes. With this method, resistance to both the methylation-sensitive restriction enzyme HpaII and the methylation-insensitive isoschizomer MspI was compared between samples by using a microarray with promoter regions of the 8091 genes. The reliability of the difference in HpaII resistance was judged using the difference in MspI resistance. We demonstrated the utility of this method by finding epigenetic mutations in cancer. Aberrant hypermethylation is known to inactivate tumour suppressor genes. Using this method, we found that frequency of the aberrant promoter hypermethylation in cancer is higher than previously hypothesized. Aberrant hypomethylation is known to induce activation of oncogenes in cancer. Genome-wide analysis of hypomethylated promoter sequences in cancer demonstrated low CG/GC ratio of these sequences, suggesting that CpG-poor genes are sensitive to demethylation activity in cancer.

Adenocarcinoma↗

PubMed2006

Enhancement of seed vigour following insecticide and phenolic elicitor treatment.

Thiamethoxam (CGA 293'343) is a novel broad-spectrum neonicotinoid insecticide. It is commercially used as a seed treatment under the trademark Cruiser (CRZ). Although many reports detail its insecticidal, plant-protecting properties, there are minimal reports concerning the effect on seed germination activities which can be key control points of seedling vigour. In this report, we investigated the effect of CRZ, fish protein hydrolysates (FPH; a known elicitor of pentose-phosphate pathway) and the combination of CRZ and FPH (CF) on seed vigour of pea, soybean and corn. Seed vigour was investigated by estimating germination percentage, shoot height, shoot weight, total soluble phenolic content, antioxidant content, G6PDH (glucose-6-phosphate dehydrogenase) activity, and GPX (guaiacol peroxidase) activity. Addition of FPH to CRZ (CF) seemed to have a slightly positive effect on seed vigour, especially, CF and FPH treatment for corn and FPH treatment for pea, suggesting that pre-sowing treatments may cause positive/negative effects on seed vigour, depending on the concentration of treatments. Further research will be needed to determine their effects and the optimal concentration for seed priming.

Antioxidants↗

PubMed2006

AURKA is one of the downstream targets of MAPK1/ERK2 in pancreatic cancer.

DUSP6/MKP-3, a specific inhibitor of MAPK1/ERK2, frequently loses its expression in primary pancreatic cancer tissues. This evidence suggests that constitutive activation of MAPK1 synergistically induced by frequent mutation of KRAS2 and the loss of function of DUSP6 plays key roles in pancreatic carcinogenesis and progression. By profiling of gene expressions associated with downregulation of MAPK1 induced by exogenous overexpression of DUSP6 in pancreatic cancer cells, we found that AURKA/STK15, the gene encoding Aurora-A kinase, which plays key roles in cellular mitosis, was among the downregulated genes along with its related genes, which included AURKB, TPX2 and CENPA. An association of expression and promoter activity of AURKA with MAPK activity was verified. Knockdown of ETS2 resulted in a reduction of AURKA expression. These results indicate that AURKA is a direct target of the MAPK pathway and that its overexpression in pancreatic cancer is induced by hyperactivation of the pathway, at least via ETS2.

Aurora Kinase A↗

PubMed2006

Effects of vascular occlusion on maximal force, exercise-induced T2 changes, and EMG activities of quadriceps femoris muscles.

The purpose of our study was to determine the effect of vascular occlusion on neuromuscular activation and/or the energy metabolic characteristics of the quadriceps femoris (QF) muscles during muscle contractions. Seven men participated in the study. An occlusion cuff was attached to the proximal end of the right thigh, so that blood flow in the anterior medial malleolar artery was reduced to approximately 88 % of the non-occluded flow. Muscle functional magnetic resonance imaging and maximal voluntary contraction (MVC) were carried out before and immediately after 5 sets of 10 repetitions of knee extension exercises at 50 % of the 10 repetitions maximum, from which transverse relaxation times (T2) and maximal force were measured, respectively. Integrated electromyography (iEMG) activity was recorded from the belly of the rectus femoris, vastus lateralis, and vastus medialis muscles during MVC and repetitive exercises. The percentage change in T2 was significantly increased for individual QF muscles, and there was a significant increase in iEMG activity over the 5 sets of repetitive exercises under conditions of vascular occlusion, but there was no significant effect on isometric force and iEMG activity during MVC. These results are consistent with the idea that there is greater osmolite accumulation during exercise with occlusion, although increased neural activation cannot be ruled out.

Adult↗

PubMed2005

The effects of ice application over the vastus medialis on the activity of quadriceps femoris assessed by muscle function magnetic resonance imaging.

AIM: The purpose of this study was to investigate the effect of ice application for the muscle vastus medialis (VM) on the activation pattern of the quadriceps femoris muscle during repetitive knee extensions using muscle function magnetic resonance imaging (mfMRI) technique. METHODS: Seven men underwent transverse relaxation time (T2)-weighted magnetic resonance imaging (spin echo, TR/TE=1500/25, 80 ms, 10 mm slice thickness and gap) of their right thigh at rest and immediately after isotonic knee extension exercise with 5 sets of 10 repetitions at a load equal to 70% of their 10 repetitions with and without skin cooling. Cooling over surface skin of the VM was carried out for 3 min before and during 60-s of each rest interval between the knee extension exercise. RESULTS: The relative change in T2 of the muscle vastus intermedius increased significantly more by skin cooling than the control (p<0.01), but not the muscle rectus femoris (RF), muscle vastus lateralis, and VM. CONCLUSION: These results suggest that selective skin cooling combined with repeated muscle contraction facilitates the activation of other synergistic muscles, making this technique useful for activating the agonist muscles expected for injured muscle in training and rehabilitation.

Adult↗

PubMed2004

Vestibular function and vasopressin.

OBJECTIVE: To investigate the relation between the vestibular system and vasopressin (AVP). MATERIAL AND METHODS: We examined the effects of electrical and caloric vestibular stimulation on plasma AVP levels in anesthetized rats. Plasma AVP levels of patients with intractable Ménière's disease who were subjected to endolymphatic drainage and steroid instillation surgery (EDSS) or intratympanic gentamicin (GM) injection were measured before and after these interventions. RESULTS: Electrical vestibular stimulation increased plasma AVP levels in a current intensity-dependent manner. Plasma AVP levels were also increased by caloric stimulation with cold water. Plasma AVP levels decreased rapidly after EDSS, and were maintained at a low level even 6-12 months following EDSS or intratympanic GM injection. CONCLUSIONS: Vestibular activation or inhibition-induced imbalance of intervestibular activities increased plasma AVP levels in rats. Therefore, vestibular disorder would seem to increase plasma AVP and thus worsen endolymphatic hydrops. EDSS rapidly decreased plasma AVP and would seem to reduce hydrops. Inhibition of vertigo spells by EDSS or intratympanic GM injection would reduce a possible stress response, resulting in a decrease in plasma AVP levels a long time after the treatments. This resultant decrease in AVP would beneficially inhibit the formation and/or maintenance of hydrops and thus prevent vertigo spells.

Animals↗

PubMed2002

Overexpression of the p53-inducible brain-specific angiogenesis inhibitor 1 suppresses efficiently tumour angiogenesis.

The brain-specific angiogenesis inhibitor 1 gene has been isolated in an attempt to find fragments with p53 "functional" binding sites. As reported herein and by others, brain-specific angiogenesis inhibitor 1 expression is present in some normal tissues, but is reduced or lost in tumour tissues. Such data and its particular structure prompted the hypothesis that brain-specific angiogenesis inhibitor 1 may act as a mediator in the local angiogenesis balance. We herein demonstrate that brain-specific angiogenesis inhibitor 1 over-expression suppresses tumour angiogenesis, delaying significantly the human tumour growth in immunodeficient mice. The inhibitory effect of brain-specific angiogenesis inhibitor 1 was documented using our intravital microscopy system, strongly implicating brain-specific angiogenesis inhibitor 1 as a mediator in the control of tumour angiogenesis. In contrast, in vitro tumour cell proliferation was not inhibited by brain-specific angiogenesis inhibitor 1 transfection, whereas some level of cytotoxicity was assessed for endothelial cells. Immunohistochemical analysis of tumour samples confirmed a reduction in the microvessel density index in brain-specific angiogenesis inhibitor 1-overexpressing tumours. At messenger level, moderate changes could be detected, involving the down-regulation of vascular endothelial growth factor and collagenase-1 expression. Furthermore, brain-specific angiogenesis inhibitor 1 expression that was lost in a selection of human cancer cell lines could be restored by wild-type p53 adenoviral transfection. Brain-specific angiogenesis inhibitor 1 should be considered for gene therapy and development of efficient drugs based on endogenous antiangiogenic molecules.

Adenocarcinoma↗

PubMed2001

Vestibular modulation of plasma vasopressin levels in rats.

Recent studies, which have shown an increase of plasma vasopressin (VP) in experimental motion sickness and the efficacy of VP antagonists for motion sickness, suggest an important role of VP in the development of vestibulo-autonomic responses. We have recently found evidence of the co-existence of vasopressinergic neurons with the stress-sensitive chemokinergic neuronal system in the hypothalamo-pituitary pathway in rats, which uses cytokine-induced neutrophil chemoattractant (CINC) as an effector molecule. In this study, to elucidate possible roles of VP and CINC in the vestibulo-autonomic responses, we simultaneously measured plasma VP and CINC concentrations after electrical or caloric vestibular stimulation in urethane-anesthetized rats. Electrical vestibular stimulation with more than 200 microA increased the plasma levels of VP in a current intensity-dependent manner, and stimulation with 500 microA increased the plasma VP levels to 350% of the normal control group, which received no stimulation. Caloric vestibular stimulation with cold water increased the plasma VP levels to 262% of the control group, which received caloric stimulation with water at 37 degrees C, and stimulation with warm water tended to increase the plasma VP levels. Plasma CINC levels were neither affected by electrical nor caloric vestibular stimulation. These findings indicate that vestibular stimulation increased plasma levels of VP but not CINC, and this vestibular-induced activation of VP neurons may be involved in a mechanism of vestibulo-autonomic responses.

Animals↗

PubMed2001

A BAC-based STS-content map spanning a 35-Mb region of human chromosome 1p35-p36.

We have devised a mapping method for rapid assembly and ordering of bacterial artificial chromosome (BAC) clones on a radiation hybrid (RH) panel, using sequence-tagged sites (STSs) and PCR. The protocol consists of two rounds of two-dimensional screening from a limited number of BACs to correspond each to an STS. In the first round, STSs are assembled in the RH bins and ordered according to PCR signals derived from 384-well microtiter plates (MTPs) in which BAC clones have been arrayed. In the second round, individual BAC clones are isolated from the MTPs to build a contig. We applied this method to a 35-Mb region spanning human chromosome 1p35-p36 and assembled 1366 BACs in 11 contigs, the longest being about 20 Mb. The working draft sequences of the human genome have been integrated into the contigs to validate the accuracy.

Chromosome Mapping↗

PubMed2001

The interacting domains of three MutL heterodimers in man: hMLH1 interacts with 36 homologous amino acid residues within hMLH3, hPMS1 and hPMS2.

In human cells, hMLH1, hMLH3, hPMS1 and hPMS2 are four recognised and distinctive homologues of MutL, an essential component of the bacterial DNA mismatch repair (MMR) system. The hMLH1 protein forms three different heterodimers with one of the other MutL homologues. As a first step towards functional analysis of these molecules, we determined the interacting domains of each heterodimer and tried to understand their common features. Using a yeast two-hybrid assay, we show that these MutL homologues can form heterodimers by interacting with the same amino acid residues of hMLH1, residues 492-742. In contrast, three hMLH1 partners, hMLH3, hPMS1 and hPMS2 contain the 36 homologous amino acid residues that interact strongly with hMLH1. Contrary to the previous studies, these homologous residues reside at the N-terminal regions of three subdomains conserved in MutL homologues in many species. Interestingly, these residues in hPMS2 and hMLH3 may form coiled-coil structures as predicted by the MULTICOIL program. Furthermore, we show that there is competition for the interacting domain in hMLH1 among the three other MutL homologues. Therefore, the quantitative balance of these three MutL heterodimers may be important in their functions.

Adaptor Proteins, Signal Transducing↗

PubMed2001

Differences in NOS protein expression and activity in the rat vestibular nucleus following unilateral labyrinthectomy.

We used Western blotting to analyse the expression of different isoforms of nitric oxide synthase (NOS) in the rat vestibular nucleus complex (VNC) at various times following unilateral vestibular deafferentation (UVD), together with a radioenzymatic assay to compare NOS activity at the same time points. nNOS expression did not change significantly in the ipsilateral or contralateral VNC at any time following UVD. However, eNOS expression decreased significantly (P<0.05) in the contralateral VNC at 6 h post-UVD, recovering to normal levels by 50 h. iNOS was not expressed at any time following UVD. NOS activity demonstrated a significant increase in the contralateral VNC at 6 h post-UVD (P<0.05), recovering toward normal levels by 50 h.

Animals↗

PubMed2001

Frequent nuclear accumulation of beta-catenin in pituitary adenoma.

BACKGROUND: Beta-catenin (CTNNB1) is known to be a member of the cadherin-catenin superfamily and to function in cell-cell adhesion. However, it also has been reported that CTNNB1 plays an important role in carcinogenesis. In the current study, the authors observed expression of the CTNNB1 protein in primary pituitary adenomas to investigate the role of CTNNB1 in the development of pituitary adenomas. METHODS: A total of 37 pituitary adenomas were analyzed. Expression of CTNNB1 and the cell proliferation marker Ki-67 were observed immunohistochemically. In addition, the authors performed direct sequencing to detect somatic mutations of exon 3 of the CTNNB1 gene. RESULTS: Twenty-one of 37 pituitary adenomas (57%) demonstrated abnormal nuclear accumulation of CTNNB1. It is interesting to note that tumors with an accumulation of CTNNB1 in the nucleus showed a statistical tendency toward an association with increased immunoreactivity of Ki-67 (P < 0.05) whereas no significant correlation was detected between the status of CTNNB1 and other clinicopathologic features. Missense mutations in exon 3 of the CTNNB1 gene also were detected in the cases with abnormal nuclear accumulation of the CTNNB1 protein. CONCLUSIONS: The results of the current study suggest that up-regulation of the Wnt signaling pathway, including accumulation of mutant CTNNB1 in the nuclei, plays an important role in the tumorigenesis and development of adenoma in the pituitary gland.

Adenoma↗

PubMed2001

Exclusion of SMAD4 mutation as an early genetic change in human pancreatic ductal tumorigenesis.

Pancreatic ductal carcinoma is one of the malignant diseases with the poorest prognosis. To develop effective methods for better treatment of pancreatic cancer patients, we tried to analyze the course of multistep carcinogenesis of the pancreatic ductal cells. IPMT (intraductal papillary-mucinous tumor) is thought to be one of the premalignant lesions of the pancreas, which would transform into carcinomas. Loss of 18q at the SMAD4 locus is known to be an early genetic change in pancreatic ductal carcinomas. It is not clear, however, whether or not the target gene for inactivation is SMAD4. Using 18 IPMTs, we analyzed LOH at the SMAD4 locus and observed frequent LOH (7/14, 50%). No mutations were observed in any of the tumors. Moreover, the expression level of the SMAD4 protein did not show a reduction in IPMTs. These results suggested that (i) inactivating mutation of the SMAD4 gene is a rather late genetic change in pancreatic carcinogenesis, and (ii) there may be an unknown tumor suppressor gene in 18q, other than SMAD4, that is involved in pancreatic ductal carcinogenesis.

Carcinoma, Pancreatic Ductal↗

PubMed2001

Homozygous deletion in a neuroblastoma cell line defined by a high-density STS map spanning human chromosome band 1p36.

Recent molecular studies have shown a relatively high rate of loss of heterozygosity (LOH) in neuroblastoma (NB) as well as other types of tumors in human chromosome band 1p36. To identify candidate tumor suppressor genes in NB, we searched for homozygous deletions in NB cell lines with PCR according to a high-density sequence tagged site (STS)-content map spanning 1p35-36. Among 25 NB cell lines examined, only one cell line, NB-1, showed no signal with 27 STSs in a 480 kb region in 1p36.2. The sequence analysis has revealed that the defective region included seven known genes (E4, KIF1B, SCYA5, PGD, Cortistatin, DFF45, and PEX14), nine expressed sequence tags (ESTs), and two microsatellite markers. These genes are related to apoptosis, an ubiquitin-proteasome pathway, a neuronal microtubule-associated motor molecule, and components of a common translocation machinery. The region between the DFF45 and KIF1B genes was defined as homozygous deletion by Southern blotting. The search in LOH regions with high-density STSs may be useful for the isolation and identification of tumor suppressor genes in other tumors as well as NBs.

Child, Preschool↗

PubMed2001

Allelic loss of the NF1 gene in anal malignant melanoma in a patient with neurofibromatosis type 1.

A 64-year-old man with neurofibromatosis type 1 (NF1) developed a primary malignant melanoma of the anus. Genetic analysis of the resected tumor confirmed loss of heterozygosity (LOH) of the NF1 gene. Anorectal malignant melanoma in NF1 is extremely rare, and genetic studies of the NF1 gene in such patients have not been reported. The allelic loss detected in the present patient supports the previously raised idea that NF1 can function as a tumor suppressor gene in the development of malignant melanoma in patients with NF1.

Anus Neoplasms↗

PubMed2001

Quantitative changes in gene expression of glutamate receptor subunits/subtypes in the vestibular nucleus, inferior olive and flocculus before and following unilateral labyrinthectomy in the rat: real-time quantitative PCR method.

Spontaneous recovery from the oculomotor and postural symptoms of unilateral labyrinthectomy (UL) is known as vestibular compensation, which is a useful model for investigation of the mechanisms of lesion-induced CNS plasticity. In the present study, to elucidate the molecular biological basis of vestibular compensation, we investigated changes in the mRNA expression of glutamate receptor subunit/subtypes in the rat central vestibular system, including the vestibular nucleus complex (VNC), inferior olive (IO), and cerebellar flocculus following UL, using a real-time quantitative polymerase chain reaction (PCR) method. In normal control animals, regional differences in the expression of several glutamate receptor subunit/subtypes, e.g., NR1 and NR2A subunits of the N-methyl-D-aspartic acid (NMDA) receptor, GluR2 and KA2 subtypes of non-NMDA receptors, and mGluR1 and mGluR7 metabotropic glutamate receptors, were consistent with previous results from studies using in situ hybridization histochemistry, suggesting that the real-time quantitative PCR method was a reliable procedure for evaluation of changes in mRNA expression. In the vestibular nucleus complex, NR2A, GluR2 and mGluR7 mRNA were ipsilaterally downregulated by 6 h following UL (P<0.05, P<0.05 and P<0.01, respectively). In the inferior olive, no changes in gene expression were observed. In the ipsilateral flocculus, KA2 mRNA expression was increased by 50 h post-UL (P<0.05). However, in the contralateral flocculus, mGluR1 mRNA was downregulated by 6 h post-UL (P<0.005). Both the increase in KA2 mRNA expression in the ipsilateral flocculus and the decrease in mGluR1 mRNA expression in the contralateral flocculus may have had the effect of reducing Purkinje cell inhibition of ipsilateral VNC neurons, thereby contributing to the rebalancing of spontaneous resting activity between the ipsilateral and contralateral VNCs. It is suggested that such changes in the activities of the floccular-VNC pathways may be important to the vestibular compensation process.

Animals↗

PubMed2001

Analysis of the human pancreatic secretory trypsin inhibitor (PSTI) gene mutations in Japanese patients with chronic pancreatitis.

Chronic pancreatitis (CP) is a continuing or relapsing inflammatory disease of the pancreas. Several studies have demonstrated that mutations in the cationic trypsinogen (PRSS1) gene and the cystic fibrosis transmembrane conductance regulator (CFTR) gene are causative of the pathogenesis in a subset of hereditary and/or idiopathic CP cases. Recently, the N34S alteration of the pancreatic secretory trypsin inhibitor (PSTI) gene has been suggested to be closely associated with the pathogenesis of hereditary and/or idiopathic CP. Herein we analyzed genetic alterations of the PSTI gene in 32 unrelated Japanese CP patients who developed juvenile-onset CP or had a family history of CP; 5 patients were found to harbor alterations in this gene. In 3 of these 5 patients, heterozygous N34S alterations were found; this frequency is significantly lower than that in Caucasian patients reported previously. Moreover, a novel homozygous G-to-A transition in the promoter region of PSTI at 215bp upstream from the translation initiation site (-215G>A) was observed in 2 patients. We further surveyed the -215G>A alteration in 117 normal individuals; none of these individuals harbored this alteration. Our results suggested that the -215G>A alteration, as well as the N34S alteration, is a predisposing factor for CP.

Adolescent↗