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Biomedical subjects

K Furuta

Publications and source records attributed to K Furuta.

At least 19 recordsLinked to original sources
PubMed2006

A comparative study of intragastric acidity during post-breakfast and pre-dinner administration of low-dose proton pump inhibitors: a randomized three-way crossover study.

BACKGROUND: The absorption and bioavailability of proton pump inhibitors is influenced by food intake. Proton pump inhibitors bind to the parietal cell active proton pump, which is maximally stimulated after dinner: usually the largest meal of the day. However, it has not been fully clarified whether the efficacy of proton pump inhibitors differs between post-breakfast and pre-dinner dosing. AIM: To perform a pH-monitoring study to clarify this issue for two low-dose proton pump inhibitors. SUBJECTS AND METHODS: The subjects were 20 healthy male volunteers (seven Helicobacter pylori-positive and 13 H. pylori-negative), who were divided into two groups of 10 and administered 15 mg lansoprazole or 10 mg rabeprazole, respectively. All subjects underwent ambulatory intragastric 24-h pH- monitoring under three conditions allocated randomly: (i) without medication, (ii) seventh day of post-breakfast administration and (iii) eighth day of pre-dinner administration of each drug. RESULTS: There was no significant difference in the percentage time during which pH > or =4.0 in the 24-h period between post-breakfast and pre-dinner administration of both drugs (56.6% vs. 55.8%; P = 0.557), although intragastric acidity during administration of both drugs was significantly lower than that without medication. CONCLUSIONS: The timing of drug administration does not significantly influence the efficacy of low-dose proton pump inhibitors.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2006

Evaluation of modified crystal violet chromoendoscopy procedure using new mucosal pit pattern classification for detection of Barrett's dysplastic lesions.

BACKGROUND: Pit pattern diagnosis is important for endoscopic detection of dysplastic Barrett's lesions, though using magnification endoscopy can be difficult and laborious. We investigated the usefulness of a modified crystal violet chromoendoscopy procedure and utilised a new pit pattern classification for diagnosis of dysplastic Barrett's lesions. METHODS: A total of 1,030 patients suspected of having a columnar lined oesophagus were examined, of whom 816 demonstrated a crystal violet-stained columnar lined oesophagus. The early group of patients underwent 0.05% crystal violet chromoendoscopy, while the later group was examined using 0.03% crystal violet with 3.0% acetate. A targeted biopsy of the columnar lined oesophagus was performed using crystal violet staining after making a diagnosis of closed or open type pit pattern with a newly proposed system of classification. The relationship between type of pit pattern and histologically identified dysplastic Barrett's lesions was evaluated. RESULTS: Dysplastic Barrett's lesions were identified in biopsy samples with an open type pit pattern with a sensitivity of 96.0%. Further, Barrett's mucosa with the intestinal predominant mucin phenotype was closely associated with the open type pit pattern (sensitivity 81.9%, specificity 95.6%). CONCLUSIONS: The new pit pattern classification for diagnosis of Barrett's mucosa was found to be useful for identification of cases with dysplastic lesions and possible malignant potential using a crystal violet chromoendoscopic procedure.

Acetates↗
PubMed2006

Activation of the Keap1/Nrf2 pathway for neuroprotection by electrophilic [correction of electrophillic] phase II inducers.

Electrophilic neurite outgrowth-promoting prostaglandin (NEPP) compounds protect neurons from oxidative insults. At least part of the neuroprotective action of NEPPs lies in induction of hemeoxygenase-1 (HO-1), which, along with other phase II enzymes, serve as a defense system against oxidative stress. Here, we found that, by using fluorescent tags and immunoprecipitation assays, NEPPs are taken up preferentially into neurons and bind in a thiol-dependent manner to Keap1, a negative regulator of the transcription factor Nrf2. By binding to Keap1, NEPPs prevent Keap1-mediated inactivation of Nrf2 and, thus, enhance Nrf2 translocation into the nucleus of cultured neuronal cells. In turn, Nrf2 binds to antioxidant/electrophile-responsive elements of the HO-1 promoter to induce HO-1 expression. Consistent with this notion, NEPP induction of an HO-1 reporter construct is prevented if the antioxidant-responsive elements are mutated. We show that NEPPs are neuroprotective both in vitro from glutamate-related excitotoxicity and in vivo in a model of cerebral ischemia/reperfusion injury (stroke). Our results suggest that NEPPs prevent excitotoxicity by activating the Keap1/Nrf2/HO-1 pathway. Because NEPPs accumulate preferentially in neurons, they may provide a category of neuroprotective compounds, distinct from other electrophilic compounds such as tert-butylhydroquinone, which activates the antioxidant-responsive element in astrocytes. NEPPs thus represent a therapeutic approach for stroke and neurodegenerative disorders.

Cell Line↗
PubMed2006

Membrane orientation of the precursor 74-kDa form of L-histidine decarboxylase.

OBJECTIVE: We previously demonstrated that, when expressed in COS-7 cells, L-histidine decarboxylase (HDC), which has neither an amino terminal signal sequence nor a hydrophobic membrane anchor, was localized in the endoplasmic reticulum (ER), although its orientation in the membrane remains to be clarified. METHODS & RESULTS: Protease digestion and immunofluorescence analyses of the cells, of which plasma membrane was selectively permeabilized, revealed that the amino terminal 50-kDa portion of HDC is hardly accessible to proteases and antibodies added exogenously from the cytosolic side. Green fluorescent protein fused with the carboxyl terminal 20-kDa region of HDC at its carboxyl terminus exhibited the same characteristics as native HDC. CONCLUSION: These results indicate that HDC is tightly associated with the ER membrane with its carboxyl terminal region exposed on the cytosolic side.

Animals↗
PubMed2006

Interobserver agreement on classifying endoscopic diagnoses of nonerosive esophagitis.

BACKGROUND AND STUDY AIMS: The majority of patients with gastroesophageal reflux disease in Japan have low-grade esophagitis, including minimal changes. A modified Los Angeles classification of esophagitis, consisting of erosive esophagitis (grades A - D) and nonerosive esophagitis (grades M and N) has been proposed and is in clinical use in Japan. However, it is unclear whether nonerosive esophagitis with only undemarcated mucosal discoloration (grade M) is clinically significant, since interobserver variations in classification have not been investigated. The aim of the present study was therefore to evaluate interobserver variance and diagnostic agreement in the diagnosis of nonerosive esophagitis (grades M and N). MATERIALS AND METHODS: A total of 84 endoscopists were enrolled to assess the grade of esophagitis in 30 patients by viewing endoscopic images of the gastroesophageal junction. The images were projected onto a screen, and all of the endoscopists reviewed them concurrently. The diagnosis was selected from the following three categories in the modified Los Angeles classification: grades N, M, or A. The endoscopists were grouped according to their experience, whether they had a board license, and whether they had received specialist training in esophagitis. The kappa coefficient of reliability was calculated. RESULTS: The kappa coefficient of reliability for all the endoscopists in the diagnosis of cases of grade M and N nonerosive esophagitis was unacceptably low at 0.22 (95 % CI, 0.21 - 0.24). Endoscopists with a board license and those who had completed a special esophagitis diagnostic course had slightly higher kappa values (0.26; 95 % CI, 0.23 - 0.30 and 0.29; 95 % CI, 0.26 - 0.32), respectively. CONCLUSIONS: Interobserver agreement on the endoscopic diagnosis of nonerosive esophagitis (grades M and N) is too low to be of clinical value.

Clinical Competence↗
PubMed2005

Helicobacter pylori infection influences symptomatic response to anti-secretory therapy in patients with GORD--crossover comparative study with famotidine and low-dose lansoprazole.

BACKGROUND AND AIM: Helicobacter pylori infection was reported to affect gastric acid secretion. We investigated the heartburn symptoms of patients with gastro-oesophageal reflux disease during sequential treatment with 40 mg of famotidine or 15 mg of lansoprazole to clarify whether H. pylori infection influences symptomatic response to anti-secretory therapy. SUBJECTS AND METHODS: The subjects were 33 gastro-oesophageal reflux disease patients, who had already been treated with a full dose of H2 receptor antagonist. First, famotidine at 20 mg b.i.d. was administered to the patients for 8 weeks. Second, famotidine was replaced with 15 mg of lansoprazole once in the morning for 8 weeks. Finally, 20 mg of famotidine was administered b.i.d. for 8 weeks instead of lansoprazole. Gastro-oesophageal reflux disease symptoms were assessed using an original visual analogue scale. RESULTS: The sequential symptomatic responses to famotidine and lansoprazole administration indicated that gastro-oesophageal reflux disease symptoms of patients during low-dose lansoprazole treatment were significantly less than those during famotidine treatment. Remission of symptoms was obtained significantly more often by famotidine therapy in patients with H. pylori infection than in patients without H. pylori infection. CONCLUSION: Low-dose lansoprazole is more effective than full-dose famotidine for the control of symptoms in patients with gastro-oesophageal reflux disease, and H. pylori infection influences the symptomatic response to H2 receptor antagonists.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed2005

A practical approach to the clinical diagnosis of Ewing's sarcoma/primitive neuroectodermal tumour and other small round cell tumours sharing EWS rearrangement using new fluorescence in situ hybridisation probes for EWSR1 on formalin fixed, paraffin wax embedded tissue.

BACKGROUND: Over 90% of Ewing's sarcoma/primitive neuroectodermal tumour (ES/PNET) cases have the t(11;22) chromosomal rearrangement, which is also found in other small round cell tumours, including desmoplastic small round cell tumour (DSRCT) and clear cell sarcoma (CCS). Although this rearrangement can be analysed by fluorescence in situ hybridisation (FISH) using routinely formalin fixed, paraffin wax embedded (FFPE) tissues when fresh or frozen tissues are not available, a sensitive and convenient detection method is needed for routine clinical diagnosis. AIMS: To investigate the usefulness of newly developed probes for detecting EWS rearrangement resulting from chromosomal translocations using FISH and FFPE tissue in the clinical diagnosis of ES/PNET, DSRCT, and CCS. METHODS: Sixteen ES/PNETs, six DSRCTs, and six CCSs were studied. Three poorly differentiated synovial sarcomas, three alveolar rhabdomyosarcomas, and three neuroblastomas served as negative controls. Interphase FISH analysis was performed on FFPE tissue sections with a commercially available EWSR1 (22q12) dual colour, breakapart rearrangement probe. RESULTS: One fused signal and one split signal of orange and green, demonstrating rearrangement of the EWS gene, was detected in 14 of 16 ES/PNETs, all six DRSCTs, and five of six CCSs, but not in the negative controls. CONCLUSIONS: Interphase FISH using this newly developed probe is sensitive and specific for detecting the EWS gene on FFPE tissues and is of value in the routine clinical diagnosis of ES/PNET, DSRCT, and CCS.

Adolescent↗
PubMed2005

Frequent overexpression of epidermal growth factor receptor (EGFR) in mammary high grade ductal carcinomas with myoepithelial differentiation.

AIMS: To evaluate the expression of common biological markers and the epidermal growth factor receptor (EGFR) in mammary high grade ductal carcinomas with myoepithelial differentiation (DCMDs). MATERIALS/METHODS: Thirty DCMDs were clinicopathologically and immunohistochemically analysed and compared with 36 control cases of high grade conventional invasive ductal carcinoma (IDC). RESULTS: EGFR, HER2/neu, oestrogen receptor, progesterone receptor, and p53 expression was seen in 21, one, three, four, and 20 of the 30 DCMDs, compared with eight, nine, 18, 17, and five of the 36 conventional IDCs (p<0.05), respectively. In 16 of the 30 DCMDs, metastases were found in the brain, lung, bone, and liver, within a maximum of 47 months (mean, 13.9) after initial surgery, whereas only four of the 36 conventional IDCs metastasised to the lung and bone within a maximum of 27 months (mean, 18.0) after initial surgery (p=0.0001). There was a significant difference in disease free survival between DCMD and conventional IDC (p=0.001). EGFR was frequently overexpressed in DCMD compared with conventional IDC, whereas the expression of HER2/neu and hormone receptors was lower in DCMD. Fluorescent in situ hybridisation revealed that the mean EGFR to chromosome 7 centromere (CEP7) ratio of the 24 DCMD cases available for evaluation was 1.03, and EGFR gene amplification was not detected in the 21 DCMD cases with EGFR overexpression. CONCLUSION: Immunohistochemistry for myoepithelial markers and EGFR is useful for the accurate diagnosis and molecular target treatment of high grade DCMD.

Adult↗
PubMed2004

Helicobacter pylori infection prevents the occurrence of the tolerance phenomenon of histamine H2 receptor antagonists.

BACKGROUND: The attenuated anti-secretory activity of H2 receptor antagonists (H2RA) during continuous administration is referred to as the tolerance phenomenon. However, it is not clarified whether Helicobacter pylori infection affects the occurrence of tolerance to H2RA. It is also not clarified whether the tolerance phenomenon occurs to a new H2RA, lafutidine. AIM: To investigate the occurrence of the tolerance phenomenon in subjects with and without H. pylori infection during the continuous administration of lafutidine and famotidine. SUBJECTS AND METHODS: Subjects were 20 healthy male volunteers (seven H. pylori positive and 13 H. pylori negative cases). All subjects were examined by ambulatory intragastric pH monitoring five times without medication, on the first and 15th day of the administration of 20 mg b.d. famotidine and 10 mg b.d. lafutidine in a cross-over fashion. RESULTS: The tolerance phenomenon was not observed in H. pylori-positive subjects during the 15-day-long administration of both H2RAs. In contrast, the tolerance phenomenon was observed in H. pylori negative subjects, which has been previously reported. CONCLUSIONS: This study demonstrated that H. pylori infection affects the tolerance phenomenon during continuous administration of H2RAs.

Acetamides↗
PubMed2004

Activation-induced cytidine deaminase expression in follicular lymphoma: association between AID expression and ongoing mutation in FL.

Activation-induced cytidine deaminase (AID) is required for somatic hypermutation (SHM) and class switch recombination (CSR) of the immunoglobulin (Ig) gene. AID has been reported to be specifically expressed in the germinal center (GC). Follicular lymphoma (FL) cells are known to be exposed to GC reaction, as characterized by a high degree of SHM with some heterogeneity in terms of intraclonal microheterogeneity and antigen selection. The heterogeneity of SHM pattern in FL intrigued us to investigate the AID expression. AID expression was investigated in 19 FL materials consisting of 15 cases of FL fresh cells and four cell lines. In all, 10 fresh cells and three cell lines expressed AID, but the others did not. SHM was investigated in 12 fresh cells and four cell lines. The ongoing mutation was significantly different between AID-positive and AID-negative FL fresh cells (unpaired Student's t-test, P=0.047). Ongoing mutation was not seen in any of the cell lines. AID expression was associated with the ongoing mutation in FL fresh cells (two-tailed Pearson's coefficient correlation, r=0.899, P=0.01). The switch off of AID expression may start in the B-lineage differentiation stage counterpart of FL after optimizing SHM, indicated by the cessation of the ongoing mutation in AID-negative FL fresh cells.

Aged↗
PubMed2001

Expression of the lysosome-associated membrane proteins in myopathies with rimmed vacuoles.

Lysosome-associated membrane proteins (LAMPs) are structural glycoproteins located on the lysosomal membrane and are thought to have an important role in protein degradation. Increased lysosomal activity is associated with the formation of rimmed vacuoles, which are observed in various muscle disorders such as inclusion body myositis (IBM) and distal myopathy with rimmed vacuole (DMRV). In the present study, we examined LAMP-1 and LAMP-2 in biopsied muscle specimens from four cases of sporadic IBM and two of DMRV, as well as six of myopathies without rimmed vacuoles. In all cases of IBM and DMRV, immunohistochemistry showed accumulation of LAMPs in the rimmed vacuoles and the subsarcolemmal portion of the vacuolated fibers. Immunoreactivities of LAMPs in the vacuolated fibers were often associated with those of cathepsin D; however, cathepsin D was not expressed on some LAMP-positive fibers. Further, atrophic muscle fibers were sometimes positive for LAMPs expression. These findings were more prominent in LAMP-2 than in LAMP-1. Thus, LAMP-2 may play an important role in the increased protein degradation in diseased muscle fibers. The increased expression of LAMPs in the vacuolated muscle fibers may be associated with the formation of rimmed vacuoles in IBM and DMRV.

Adult↗
PubMed2001

Expression of fas/fas ligand (fasL) and its involvement in infiltrating lymphocytes in hepatocellular carcinoma (HCC).

BACKGROUND: This study was conducted to examine the expression of Fas/Fas ligand (FasL), to elucidate its relationship with tumor-infiltrating lymphocytes (TILs), and to detect possible gene mutation of Fas/FasL in patients with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC). METHODS: Indirect immunohistochemical staining was performed on formalin-fixed, paraffin-embedded sections of liver biopsy and surgery specimens from five normal livers, and from the livers of 30 patients with HCC. Fas/FasL mRNA-expressing cells and apoptotic cells were detected by in situ hybridization and DNA nick end labeling (TUNEL), respectively. We also performed polymerase chain reaction (PCR)-amplifying and direct sequencing for the Fas/FasL gene. RESULTS: Fas/FasL and its mRNA were localized on the membrane or in the cytoplasm in some HCC cells, as well as hepatocytes. Their expression was enhanced in areas with infiltrating inflammatory cells in the noncancerous regions of liver tissue and on the margins of the cancerous tissue. The positivity rate for TUNEL was elevated along these margins. The labeling index of Fas/FasL was lower in the cancerous liver tissue than in the surrounding noncancerous region (P < 0.01), and tended to decrease in proportion to the malignancy of tumor cells; Fas/FasL expression was not found on poorly differentiated type cancer cells. Fas(-)/FasL(+), FasL-mRNA(+) HCC cells were seen in one specimen of moderately differentiated type. Some CD8+T lymphocytes were TUNEL-positive around the cancerous region. In this study, cancerous and noncancerous tissues in HCC revealed no genetic mutations in any exons of Fas/FasL. CONCLUSIONS: These findings suggest that Fas/FasL expression was decreased in proportion to the malignancy of tumor cells, and that infiltrating CD8+ T lymphocytes play a role in apoptosis in HCC. The apoptosis in HCC could be regulated by the suppression of Fas/FasL expression, or, sometimes, by the enhancement of FasL expression.

Aged↗
PubMed2001

Expression of lysosome-associated membrane proteins in human colorectal neoplasms and inflammatory diseases.

The lysosome-associated membrane proteins (LAMPs)-1 and -2 are major constituents of the lysosomal membrane. These molecules are known to be among the most glycosylated proteins of several types of cells and cancer cells, and their expression in cancer cells is marked by a distinct difference in the structures of the oligosaccharides as compared to nonmalignant cells. We analyzed by immunohistochemistry the intensity and distribution of LAMP-1 and LAMP-2 in 9 human colorectal cancer cases and in 16 control cases, including inflammatory diseases (diverticulitis, ulcerative colitis, and Crohn's disease). LAMP proteins were expressed more intensely in the epithelium of colorectal neoplasms than in normal mucosa (P < 0.05), and no significant differences were found between adenoma and cancer cells (P > 0.05) in the same tissue section. Further, in sites of inactive inflammatory diseases and nonneoplastic areas in cancer specimens, no significant increases in epithelial LAMP proteins were observed, even in the proliferative zone of the lower crypt epithelium. Northern blot analysis showed increased expression of LAMP-1 and LAMP-2A in two of three colorectal cancers examined and increased LAMP-2B in all three cancers. Our findings suggest that LAMPs are related to neoplastic progression, but there is no direct association between the expression of LAMP molecules and cell proliferation.

Adenocarcinoma↗
PubMed2001

Evidence for distinct membrane traffic pathways to melanosomes and lysosomes in melanocytes.

We report here morphologic and biochemical evidence that melanosomes are distinct from lysosomes. Immunofluorescence analysis revealed that TRP-1, a melanosomal membrane protein, did not colocalize with lysosomal membrane proteins LAMP1 and LGP85 in melan-a cells. Wortmannin treatment of melanocytes enhanced the distinct compartmentalization of these melanosomal/lysosomal membrane proteins by the swelling of the endosomal-lysosomal systems. The heavily melanized melanosomes did not have an altered shape, which suggests a lesser degree of membrane dynamics of stage IV melanosomes. Terminal lysosomes loaded with TR-dextran are also distinct from melanosomes, thus indicating that melanosomes are isolated from the endocytic pathway that is a representative route to lysosomes. Because AP-3 mutation leads to mistargeting of both melanosome and lysosome membrane proteins, we propose that there is a late sorting step for melanosomes and lysosomes in melanocytes after AP-3 sorting.

Androstadienes↗
PubMed2001

Neurotrophic actions of novel compounds designed from cyclopentenone prostaglandins.

Previously we found that some cyclopentenone prostaglandin derivatives promoted neurite outgrowth from PC12 cells and dorsal root ganglia explants in the presence of nerve growth factor; and so we referred to them as neurite outgrowth-promoting prostaglandins (NEPPs). In this study, NEPPs protected HT22 cells against oxidative glutamate toxicity. NEPP6, one of the most effective promoters of neurite outgrowth in PC12 cells, protected the cells most potently among NEPPs 1--10. Several derivatives, NEPPs 11--19, were newly synthesized based on the chemical structure of NEPP6. NEPP11 had a more potent neuroprotective effect than NEPP6. NEPP11 also prevented the death of cortical neurons induced by various stimuli and reduced ischemic brain damage in mice. Biotinylated compounds of NEPPs were synthesized to investigate their cellular accumulation. NEPP6-biotin protected the cells and emitted potent signals from the cells. In contrast, biotinylated non-neuroprotective derivatives emitted much weaker signals. These results suggest that NEPPs are novel types of neurotrophic compounds characterized by their dual biological activities of promoting neurite outgrowth and preventing neuronal death and that their accumulation in the cells is closely associated with their neuroprotective actions.

Animals↗
PubMed2001

A mutation of the Wilson disease protein, ATP7B, is degraded in the proteasomes and forms protein aggregates.

BACKGROUND & AIMS: Wilson disease is a genetic disorder characterized by the accumulation of copper in the body as a result of a defect of copper excretion from hepatocytes. The intracellular localization of the Wilson disease gene product, ATP7B, was recently identified as the late endosomes. Various mutations have been documented in patients with Wilson disease. The clinical manifestations vary greatly among the patients; however, there is little information on the genotype-phenotype correlation. METHODS: We investigated the distribution of a common ATP7B mutant His1069Gln and a mutant Asp1270Ser by expressing the mutants tagged with green fluorescent protein in Huh7 and HEK293 cells. Intracellular organelles were visualized by fluorescence microscopy. RESULTS: Although the wild-type ATP7B and Asp1270Ser mutant localized in the late endosomes, His1069Gln mutant did not locate in the late endosomes and was degraded by the proteasomes in the cytoplasm. Furthermore, His1069Gln formed aggresomes composed of the degradates and intermediate filaments at the microtubule-organizing center. These aggresomes were similar to Mallory bodies on electron microscopy. CONCLUSIONS: The different protein properties of ATP7B mutants may explain the variety of clinical spectrums in patients with Wilson disease.

Acetylcysteine↗