Biomedical subjects

T Arakawa

Publications and source records attributed to T Arakawa.

At least 37 records · Page 2Linked to original sources

PubMed2003

Mast cell chymase expression in Helicobacter pylori-associated gastritis.

AIMS: To study the role of mast cell chymase in the inflammatory processes of human chronic gastritis. Experimental studies have shown that mast cell chymase stimulates inflammatory cell accumulation, and contributes to angiotensin II formation. METHODS AND RESULTS: Tissue sections from human stomachs with Helicobacter pylori-associated gastritis (surgery/autopsy n = 20; biopsy n = 16) and normal stomachs (n = 10) were studied using immunohistochemical single and double labelling techniques. Monoclonal antibodies used were directed against mast cell chymase, tryptase, neutrophils (CD66b, elastase, and myeloperoxidase), macrophages, T-lymphocytes, and interleukin (IL)-4. The expression of angiotensin-converting enzyme and angiotensin II type 1 receptor was investigated using immunohistochemical analysis and the reverse transcription-polymerase chain reaction. The number of chymase-positive mast cells was significantly higher (P < 0.0001) in H. pylori-associated gastritis than in normal stomachs. Increased expression of chymase in inflamed mucosa was closely related to an increase in the accumulation of neutrophils, macrophages, T-lymphocytes, and IL-4-positive cells. The expression of angiotensin-converting enzyme and angiotensin II type 1 receptor was not altered in gastritis specimens. CONCLUSIONS: These observations suggest that mast cell chymase may be an important mediator in the inflammatory processes of human H. pylori-associated gastritis.

Chronic Disease↗

PubMed2002

Platelet recovery after eradication of Helicobacter pylori in patients with idiopathic thrombocytopenic purpura.

The association between Helicobacter pylori ( H. pylori) infection and idiopathic thrombocytopenic purpura (ITP) has been reported by several groups. We investigated the prevalence of H. pylori infection and the effectiveness of its eradication in Japanese patients with ITP. H. pylori infection was found in 21 of 30 patients (70.0%) by (13)C urea breath test and presence of serum antibodies to H. pylori. H. pylori was eradicated in 18 of the 21 infected patients (85.7%) by administration of a proton pump inhibitor and two kinds of antibiotics. In only one patient was medication discontinued due to skin rash on the 4th day of treatment. Platelet recovery was obtained in ten patients (55.6%). In two patients with treatment failure, platelet recovery was obtained after successful re-eradication. In three patients without H. pylori infection, platelet counts did not significantly increase with the same treatment. On the other hand, eradication therapy did not affect platelet counts in patients with gastric ulcer. In conclusion, H. pylori eradication can be used for initial treatment with tolerable adverse effects in some ITP patients.

Adult↗

PubMed2002

Differential gene expression of vascular endothelial growth factor isoforms and their receptors in the development of the rat masseter muscle.

The capillary network in the masseter muscle develops dramatically with the differentiation of muscle fibres after birth, especially around weaning. Here, developmental changes in mRNA expression for four splicing variants of vascular endothelial growth factor (VEGF) and for two distinct VEGF receptors (Fms-like tyrosine kinase (Flt-1) and kinase insert domain-containing receptor/fetal liver kinase-1 (KDR/Flk-1)) were studied in rat masseter. The relative abundance of VEGF (120) mRNA was the highest, representing 35% of total VEGF mRNA on day 7 after birth and gradually decreased with age to become approximately 5% on day 37. In contrast, VEGF (188) mRNA was very low in the newborn rat, but increased sharply before weaning and reached 40-50% of the total on day 50. Neither VEGF (144) nor VEGF(164) mRNA showed any significant change in abundance after birth. The expression of KDR/Flk-1 mRNA was transiently high in the early postnatal stage and gradually decreased with age, Flt-1 mRNA was stably expressed at a constant level after birth. These findings suggest that different combinations of VEGF isoforms and their receptors regulate angiogenesis in the development of the masseter muscle.

Alternative Splicing↗

PubMed2002

Endoscopic resection of a cavernous haemangioma of the stomach.

A lesion, suspected, from the endoscopic appearance, to be an isolated gastric haemangioma was incidentally detected in a 66-year-old male. At follow-up endoscopy, 5 years later, tumour size had increased and its appearance had changed with respect to previous examinations. On endoscopic ultrasonography, the tumour was solid and confined mainly to the submucosal layer of the gastric wall. Examination of biopsy specimens failed to provide any useful information. After biopsy, tumour size and the area of reddish discoloration decreased and endoscopic ultrasonography revealed multiple small cystic lesions in the tumour. Endoscopic resection was then performed with complete excision of the tumour without complications or recurrence. Pathological examination of resected tissue demonstrated cavernous haemangioma of the stomach.

Aged↗

PubMed2002

High molecular protein of Helicobacter pylori responsible for inhibition of ornithine decarboxylase activity of human gastric cultured cells.

BACKGROUND: Ornithine decarboxylase (ODC), a rate-limiting enzyme of polyamine biosynthesis, mediates epithelial cell proliferation and plays a critical role in the optimal repair of gastric mucosal damage. Several studies have shown that Helicobacter pylori inhibits the growth and proliferation of gastric cells in vitro. AIM: To test whether H. pylori extract affects ODC mRNA expression and its enzyme activity in gastric cells and to examine the partial characterization of the molecule responsible for this effect. METHODS: Human gastric cells (MKN-45) were used. Bacterial extracts from various E. coli or H. pylori strains, namely (1) cagA+, vacA+, CagA+, VacA+; (2) cagA+, vacA+, CagA+ VacA-; or (3) cagA-, vacA+, CagA-, VacA- were added to the cells. Cell proliferation was assessed by [3H]-thymidine incorporation, viability by MTT assay and LDH release test, ODC enzyme activity by 14CO2 counts from L-[1(14)C]ornithine, and ODC mRNA by Northern blotting. RESULTS: H. pylori and E. coli extract did not affect viability of gastric cells. H. pylori extract, especially extracts containing a protein greater than 50 kDa, significantly inhibited proliferation and ODC activity of gastric cells while E. coli extract had no effect. Inhibition of ODC activity was found in extracts of all H. pylori strains, irrespective of CagA and VacA protein expression. Serum stimulation induces an increase in ODC mRNA while H. pylori extract did not affect ODC mRNA expression. CONCLUSION: High molecular weight (greater than 50 kDa) proteins of H. pylori extract without CagA or VacA protein inhibited proliferation and ODC activity of human gastric cells, but did not affect ODC mRNA expression, suggesting that inhibition of ODC activity is regulated at the post-transcriptional level.

Antigens, Bacterial↗

PubMed2002

Increased expression of epidermal growth factor receptors in basal cell hyperplasia of the oesophagus after acid reflux oesophagitis in rats.

BACKGROUND: Epidermal growth factor (EGF), which binds to EGF receptors (EGF-R), stimulates oesophageal epithelial cell proliferation, enabling rapid repair after mucosal injury. In the normal human oesophageal epithelium, EGF-R expression is present and confined to the basal layer. AIM: To examine histological changes in and dynamics of EGF-R expression during healing after acid reflux oesophagitis in a rat model. METHODS: Gastric acid reflux oesophagitis was induced in Wistar rats by ligation of the pylorus and the transitional region between the forestomach and the grandular portion for 5 h, followed by release of both ligations. Rats were killed 7 and 14 days after production of oesophagitis to examine macroscopic and histological changes as well as dynamics of EGF-R expression. Epithelial cell proliferation was assessed by bromodeoxyuridine (BrdU) uptake, and expression of EGF-R mRNA and protein by RT-PCR and Western blotting or immunohistochemistry. RESULTS: Gastric acid reflux induced erosive and ulcerative mucosal lesions in the lower and middle part of the oesophagus. These lesions were healed by 14 days and histologically showed thickening of the oesophageal epithelium from 41.11 +/- 3.09 microm in controls to 142.73 +/- 11.59 microm (P < 0.001) in ligated rats, as well as elongation of papillae and basal cell hyperplasia. The number of BrdU-positive cells among basal cells on day 14 was significantly increased from 7.1 +/- 0.8/field in controls to 30.9 +/- 3.0/field in ligated rats. Expression of EGF-R mRNA and protein was significantly increased on day 14 and most basal cells were immunohistochemically positive in both BrdU and EGF-R staining. CONCLUSION: Acid reflux-induced oesophageal injury caused basal cell hyperplasia with an increase in cell proliferation and EGF-R expression. Activation of EGF-R gene and protein in response to acid reflux-induced injury may facilitate mucosal healing. These results suggest that epidermal growth factor receptors play a crucial role in healing after acid reflux oesophagitis in rats.

Amino Acid Sequence↗

PubMed2002

Effects of ecabet sodium, an antiulcer drug, on gastric adaptive relaxation in isolated guinea-pig stomachs.

Disturbances in the reservoir function of the stomach may cause epigastric fullness or early satiety, which are the main symptoms in patients with dysmotility-like functional dyspepsia. Gastric adaptive relaxation is involved in the reservoir function of the proximal stomach. Ecabet sodium, synthesized from abietic acid, is widely used in Japan as an antiulcer drug. The purpose of this study was to evaluate the effects of ecabet on gastric adaptive relaxation in isolated guinea-pig stomachs. Changes in intragastric volume and pressure were recorded in the presence of atropine and guanethidine. Gastric adaptive relaxation was triggered by luminal distention. Ecabet at the dose of 20 mmol/l in solutions at two pHs (pH 3.0 and 7.4) significantly lowered the threshold pressure needed for such relaxation and increased intragastric volume, but lower doses had little or no effect. The results suggested that this antiulcer drug might improve symptoms in patients with dysmotility-like functional dyspepsia.

Abietanes↗

PubMed2001

Determination of carbohydrate contents from excess light scattering.

In the light scattering technique, glycosylation gives rise to excess light scattering for glycoproteins. Assuming additivity of refractive index and using an appropriate refractive index increment for carbohydrate, one can determine the degree of glycosylation from the excess light scattering. Here we have used size-exclusion chromatography in combination with online light scattering, UV absorbance, and refractive index. The results show that the technique accurately determines the carbohydrate content of recombinant stem cell factor.

Animals↗

PubMed2001

The membrane-anchored MMP inhibitor RECK is a key regulator of extracellular matrix integrity and angiogenesis.

Matrix metalloproteinases (MMPs) are essential for proper extracellular matrix remodeling. We previously found that a membrane-anchored glycoprotein, RECK, negatively regulates MMP-9 and inhibits tumor invasion and metastasis. Here we show that RECK regulates two other MMPs, MMP-2 and MT1-MMP, known to be involved in cancer progression, that mice lacking a functional RECK gene die around E10.5 with defects in collagen fibrils, the basal lamina, and vascular development, and that this phenotype is partially suppressed by MMP-2 null mutation. Also, vascular sprouting is dramatically suppressed in tumors derived from RECK-expressing fibrosarcoma cells grown in nude mice. These results support a role for RECK in the regulation of MMP-2 in vivo and implicate RECK downregulation in tumor angiogenesis.

Animals↗

PubMed2001

NaCl-activated nucleoside diphosphate kinase from extremely halophilic archaeon, Halobacterium salinarum, maintains native conformation without salt.

Enzymes from extremely halophilic archaea are readily denatured in the absence of a high salt concentration. However, we have observed here that a nucleoside diphosphate kinase prepared from Halobacterium salinarum was active and stable in the absence of salt, though it has the amino acid composition characteristic of halophilic enzymes. Recombinant nucleoside diphosphate kinase expressed in Escherichia coli requires salt for activation in vitro, but once it acquires the proper folding, it no longer requires the presence of salts for its activity and stability.

Amino Acid Sequence↗

PubMed2001

Factors affecting short-term and long-term stabilities of proteins.

Proteins are marginally stable and, hence, are readily denatured by various stresses encountered in solution, or in the frozen or dried states. Various additives are known to minimize damage and enhance the stability of proteins. This review discusses the current knowledge of the mechanisms by which these additives stabilize proteins against acute stresses, and also the various factors to be considered for long-term storage of proteins in solution.

Drug Stability↗

PubMed2001

Functional annotation of a full-length mouse cDNA collection.

The RIKEN Mouse Gene Encyclopaedia Project, a systematic approach to determining the full coding potential of the mouse genome, involves collection and sequencing of full-length complementary DNAs and physical mapping of the corresponding genes to the mouse genome. We organized an international functional annotation meeting (FANTOM) to annotate the first 21,076 cDNAs to be analysed in this project. Here we describe the first RIKEN clone collection, which is one of the largest described for any organism. Analysis of these cDNAs extends known gene families and identifies new ones.

Animals↗

PubMed2001

Expression and purification of cytokine receptor homology domain of human granulocyte-colony-stimulating factor receptor fusion protein in Escherichia coli.

Direct expression of the cytokine receptor homology (CRH) domain of granulocyte-colony-stimulating factor (G-CSF) receptor is lethal to Escherichia coli. For the efficient and stable production of an active CRH domain in E. coli, we fused the CRH domain with different proteins, such as maltose-binding protein (MalE), glutathione S-transferase, and thioredoxin (Trx). Among these, Trx appeared to be the best in terms of the protein expression level, purification efficiency by affinity chromatography, and binding activity to its ligand, G-CSF. The yield of active Trx-CRH fusion protein increased about 200-fold compared to that of previously reported MalE-CRH fusion.

ATP-Binding Cassette Transporters↗

PubMed2001

Expression, purification, and characterization of the active immunoglobulin-like domain of human granulocyte-colony-stimulating factor receptor in Escherichia coli.

We succeeded in the expression, purification, and refolding of the immunoglobulin-like (Ig) domain of human granulocyte-colony-stimulating factor (G-CSF) receptor with amino-terminal His-tag in Escherichia coli. The refolded Ig domain bound to a G-CSF affinity column and could be eluted with free G-CSF as a receptor-ligand complex, demonstrating that the Ig domain has the information necessary for binding its ligand, G-CSF. The eluted His-Ig/G-CSF complex could be separated from excess G-CSF by Ni-NTA column chromatography. The yield of this active recombinant His-Ig protein is about 0.72 mg per liter of culture. Its small size and the ease of production make this receptor fragment a useful reagent for the structural analysis of its complex with G-CSF.

Amino Acid Substitution↗

PubMed2001

Gene expression analysis in colorectal cancer using practical DNA array filter.

PURPOSE: We examined the usability of a newly developed, compact-sized DNA array filter for studying the gene expression pattern of individual colorectal cancer. METHODS: Complementary DNA probes were prepared from mRNA extracted from colonic cancer specimens and adjacent normal mucosa and then were labeled with chemiluminescence. These labeled probes were allowed to bind to the gene fragments on the filter. A specialized scanning charge-coupled device camera measured the intensity of each chemiluminescent spot, which is an indicator of the degree to which a specific gene is expressed. Gene expression image was quantified into intensity of signals by using computer software. RESULTS: Characteristic gene expression patterns were obtained from the colonic cancer cell line, RPMI4788, and the leukemia cell line, HL60, by using this compact-sized DNA array filter in the preliminary experiment. Up-regulation of nm23, TIMP1, VEGF, and cyclin E and down-regulation of some tumor suppressor genes (p53, TOSO, and SIVA), beta-catenin, and metallothionein were observed in colonic cancer specimen when compared with those of normal mucosa. CONCLUSIONS: We have obtained unique gene expression patterns from colorectal cancer and normal tissue by using a newly developed compact-sized DNA array filter system. Collecting, storing, and analyzing of gene expression data from many samples of colorectal cancer will enable us to identify distinct subsets of patients based on molecular characteristics in the near future.

Cell Line↗

PubMed2001

Prevalence of Helicobacter pylori infection in gastric remnant after distal gastrectomy for primary gastric cancer.

BACKGROUND: The development of a second primary cancer in the gastric remnant after gastrectomy for early gastric carcinoma is a problem, and eradication of Helicobacter pylori after the operation has been recommended. However, to date, practical indications for H. pylori eradication after gastric cancer surgery have not yet been reported. METHODS: We examined H. pylori infection in the gastric remnant after distal gastrectomy for primary gastric cancer. One hundred and nine patients who had had a gastrectomy were studied. Endoscopic findings and results from the urease test, bacteriologic assessment, serological test, and histopathological examination were analyzed. RESULTS: Seventy-one patients (65.1%) were judged to be positive for H. pylori infection. The prevalence of H. pylori infection was found to be significantly decreased in older patients, patients in whom the operation had been performed a long time before examination, patients with symptoms, and patients with severe reflux gastritis. On the other hand, histologically, chronic and acute gastritis correlated significantly with H. pylori infection. H. pylori prevalence was highest in mildly atrophic mucosa and decreased with more extensive atrophic changes of the mucosa. CONCLUSIONS: The persistence of H. pylori-related active gastritis in the gastric remnant after gastric cancer surgery was suggested in younger patients with mild atrophic gastritis and without reflux gastritis. These patients may be the best candidates for H. pylori eradication therapy.

Adult↗

PubMed2001

Differential expression of human beta-defensin 2 in keratinized and non-keratinized oral epithelial lesions; immunohistochemistry and in situ hybridization.

Human beta-defensin(hBD)-2, an antimicrobial peptide, is produced by various epithelial cells. Because hBD-2 expression in the oral epithelium has not been assessed, we investigated its localization in normal oral epithelium and epithelial lesions. hBD-2 expression was studied using immunohistochemistry and in situ hybridization on formalin-fixed, paraffin-embedded tissue sections from 30 cases of squamous cell carcinoma and 6 cases of leukoplakia. Immunostaining for hBD-2 was more intense in hyperkeratinized than in ortho- or non-keratinized epithelium. In contrast, signals for hBD-2 mRNA were frequently stronger in non-keratinized epithelium than in hyper- or ortho-keratinized epithelium. The results suggest that keratinization in oral epithelium plays an important role in the biological function of hBD-2 both at the mRNA level and in the retention of the peptide in the epithelium.

Carcinoma, Squamous Cell↗

PubMed2001

Arterial remodeling influences the development of intimal hyperplasia after stent implantation.

OBJECTIVES: We examined whether preinterventional arterial remodeling influenced the interventional results after stenting. BACKGROUND: Arterial remodeling is seen in atherosclerotic lesions, and it may play an important role in the early stage of atherosclerosis. METHODS: We examined 113 lesions that underwent elective stenting using tubular slotted stents under intravascular ultrasound guidance. The lesions were divided into three groups--adequate, intermediate and inadequate remodeling group--according to preinterventional arterial remodeling. The patients were subjected to coronary angiography and intravascular ultrasound evaluation on average 6.4 months after stenting. RESULTS: At baseline and immediately after stenting, there were no differences in quantitative angiographic analysis among remodeling groups. However, the plaque cross-sectional area (CSA) in the minimal lumen CSA at preintervention and intimal hyperplasia CSA at follow-up were significantly larger in the adequate remodeling group than in the inadequate remodeling group. The restenosis rate of stenting for the lesions with inadequate arterial remodeling was very low (9.4%). A significant positive correlation was found between preinterventional plaque CSA and intimal hyperplasia CSA at follow-up (r = 0.47, p < 0.0001). Moreover, remodeling index significantly correlated with relative intimal hyperplasia CSA (r = 0.28, p < 0.01). CONCLUSIONS: Preinterventional arterial remodeling influenced the development of intimal hyperplasia after stenting.

Aged↗