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Biomedical subjects

A Ohashi

Publications and source records attributed to A Ohashi.

At least 37 records · Page 2Linked to original sources
PubMed2002

Endoscopic transpapillary bile duct biopsy with the combination of intraductal ultrasonography in the diagnosis of biliary strictures.

BACKGROUND: When endoscopic retrograde cholangiopancreatography (ERCP) guided bile duct biopsy fails to demonstrate malignancy, it remains unclear how to manage patients with presumably malignant strictures. AIMS: To evaluate the value of intraductal ultrasonography (IDUS) when bile duct biopsy is negative. METHODS: Sixty two patients with strictures of the bile duct were studied prospectively. During ERCP, IDUS was performed using an ultrasonic probe (diameter 2.0 mm; frequency 20 MHz). Following IDUS, a bile duct biopsy was performed using forceps (diameter 1.8 mm). The IDUS images of the tumour were classified as polypoid lesions, localised wall thickening, intraductal sessile tumours, sessile tumour outside of the bile duct, or absence of apparent lesion. The bile duct wall structures at the site of the tumour as well as the maximum diameter of the tumour were also analysed. The IDUS findings were compared with the histological findings or clinical course. RESULTS: When the IDUS images showed a polypoid lesion (n=19), localised wall thickening (n=8), intraductal sessile tumour (n=13), and sessile tumour outside of the bile duct (n = 20), the sensitivities of the biopsy were 80%, 50%, 92%, and 53%, respectively. Multiple regression analysis showed that the presence of sessile tumour (intraductal or outside of the bile duct: p<0.05), tumour size greater than 10.0 mm (p<0.001), and interrupted wall structure (p<0.05) were independent variables that predicted malignancy. CONCLUSION: When biopsy fails to demonstrate evidence of malignancy, the presence of sessile tumour (intraductal or outside of the bile duct), tumour size greater than 10.0 mm, and interrupted wall structure on IDUS images are factors that can predict malignancy.

Adult↗
PubMed2002

Polyclonal nature of diffuse proliferation of interstitial cells of Cajal in patients with familial and multiple gastrointestinal stromal tumours.

BACKGROUND: Diffuse proliferation of interstitial cells of Cajal (ICCs) in the myenteric plexus layer of the intestine has been described in patients with familial and multiple gastrointestinal stromal tumours (GISTs). However, it is not fully understood whether proliferation is polyclonal or monoclonal. AIMS: To evaluate the clonal nature of diffuse ICC proliferation in familial and multiple GIST cases, we carried out clonal analysis using inactivation at the human androgen receptor (HUMARA) locus. MATERIALS AND METHODS: Diffuse ICC proliferation tissues from three female patients were microdissected using a laser capture microdissection (LCM) system. Normal intestinal mucosal tissues were also microdissected for polyclonal controls and GIST tissues for monoclonal controls from the same patients, and genomic DNA was extracted. After digestion by restriction enzyme HhaI, the HUMARA locus was amplified by a fluorescent polymerase chain reaction (PCR) procedure and the PCR products were analysed. RESULTS: One case was uninformative because it was homozygous at the HUMARA locus. In the two other cases, PCR products from the diffuse ICC proliferation showed two alleles as well as those from normal intestinal mucosal tissues, indicating that ICC proliferation was polyclonal. In contrast, PCR products from associated GIST tissues showed only one allele, indicating that GISTs were monoclonal. CONCLUSION: The results suggested that diffuse ICC proliferation in familial and multiple GIST cases was non-neoplastic hyperplasia.

Cell Division↗
PubMed2002

Molecular and conventional analyses of microbial diversity in mesophilic and thermophilic upflow anaerobic sludge blanket granular sludges.

The microbial community structure of mesophilic (35 degrees C) and thermophilic (55 degrees C) methanogenic granular sludges was surveyed by using both cultivation-independent molecular approach and conventional cultivation technique in order to address the fundamental questions on the microbial populations, i.e. who are present, where they are located, and what they are doing there. To elucidate the microbial constituents within both sludges, we first constructed 16S ribosomal DNA clone libraries, and partial sequencing of the clones was conducted for phylogenetic analysis. In this experiment, we found a number of unidentifiable clones within the domain Bacteria as well as clones that were closely related with 16S rDNAs of cultured microbes. The unidentifiable clones accounted for approximately 60-70% of the total clones in both mesophilic and thermophilic libraries. 16S rRNA-targeted in situ hybridization combined with confocal laser scanning microscopy was subsequently employed to examine where the uncultured populations were located within sludge granules. Spatial organization of uncultured microbes was visualized in thin-sections of both types of granules using fluorescent oligonucleotide probes, which were designed based on the clone sequences of certain novel clusters. This resulted in the detection of two types of uncultured cells in specific locations inside the granules. Finally, the goal-directed conventional cultivation technique was employed to recover such uncultured anaerobes and uncover their physiology and functions. In this approach, a total of five new species of thermophilic microorganisms were isolated, including several types of syntrophs and a novel sugar-fermenting bacterium. In the previous molecular approaches, all of these isolates were suggested to be significant populations within thermophilic granular sludge, hence obtaining these isolates in pure culture decreased the fraction of unknown clones in the previous thermophilic clone library from 70% to 40%. In conclusion, these approaches successfully revealed biodiversity and spatial organization of microbes of interest in sludge granules, and enlarged the fundamental knowledge of microbial constituents functioning as significant populations in the UASB processes.

Bacteria, Anaerobic↗
PubMed2002

Pilot-plant study on anaerobic treatment of a lipid- and protein-rich food industrial wastewater by a thermophilic multi-staged UASB reactor.

An on-site pilot-scale experiment was conducted to investigate the performance of a multi-staged UASB (MS-UASB) reactor by feeding with a food processing wastewater containing high strength of lipid and protein. The reactor was operated at a thermophilic condition (55 degrees C) for a period of 600 days. The reactor finally achieved 50 kgCOD.m(-3) d(-1) with a soluble COD removal of 90% (based on the influent total COD versus the effluent filtered COD), while the overall COD removal (based on the effluent COD-total) as considerably unsatisfactory at around only 60-70%. The presence of high strength of lipid and protein along with high concentration of Mg and Ca ions in the raw wastewater caused a severe scum and/or insolubilized substance formation within the UASB sludge bed, resulting in hindering the contact efficiency between substrate and sludge. The replacement of active microbial granules in the sludge bed with the insolubilized protein and lipid brought about deterioration of sludge methanogenic activity.

Bacteria, Anaerobic↗
PubMed2002

Removal of indigenous coliphages and fecal coliforms by a novel sewage treatment system consisting of UASB and DHS units.

A novel sewage treatment system, which consists of an upflow anaerobic sludge blanket (UASB) pre-treatment unit and the following downflow hanging sponge (DHS) unit for polishing up the UASB effluent, was developed as a cost-effective and easy-maintenance sewage treatment system for developing countries. A long-term experiment with actual sewage was conducted in order to evaluate its treatment efficiency of organic substances, nutrients, and pathogen indicator microorganisms such as total coliphages, F+-specific RNA coliphages (RNA coliphages), and fecal coliforms. The main objective of this paper is to investigate the removal efficiency of those indicator microorganisms by the UASB-DHS combined system. The results obtained from the continuous flow experiment indicated a fairly promising removal of the indicator microorganisms, i.e., the log10 reductions of total coliphages, RNA coliphages, and fecal coliforms (based on sewage and DHS effluent) achieved were 2.01 log, 2.02 log, and 2.57 log, respectively. The UASB-DHS combined system was superior to the conventional activated sludge process in the reduction of fecal coliforms, but in the reductions of total and RNA coliphages, the system showed somewhat less removal efficiency. The vertical reducing patterns of the indicator microorganisms along the DHS reactor were also discussed.

Bacteria, Anaerobic↗
PubMed2001

Highly enantioselective hydrogenation of alpha-dehydroamino acids by rhodium complexes with new unsymmetric P-chirogenic bisphosphine ligands.

[figure: see text] New rhodium catalysts with unsymmetric P-chirogenic bis(phosphino)ethanes, BisP*-Rh, exhibited very high enantioselectivity (98-99%) in the hydrogenation of alpha-dehydroamino acid derivatives. Such high enantioselectivity should result from the asymmetric environment around the Rh atom, as was shown in the molecular structure of the catalyst analyzed by X-rays. The asymmetry can be controlled by the combination of the alkyl groups on the two phosphorus atoms.

Journal Article↗
PubMed2001

Cholangiographic findings of early-stage extrahepatic bile duct carcinoma.

BACKGROUND: To clarify the cholangiographic findings of early-stage (T1, tumor confined to the mucosal or fibromuscular layer) extrahepatic bile duct carcinoma. METHODS: Cholangiographic images were retrospectively analyzed without other information in 55 patients with extrahepatic bile duct carcinoma who underwent surgical treatment. Tumor stages were T1 (n = 10). T2 (n = 17), and T3 (n = 28). Cholangiographic findings were classified as "diffuse sclerosis," "stenosis," "papillary polypoid filling defect," or "nodular polypoid filling defect". "Papillary polypoid filling defect" was the term used when the width of the base was smaller than the width of the polypoid filling defect. RESULTS: T1 patients showed papillary polypoid filling defects (n = 8) or nodular polypoid filling defects (n = 2) on cholangiography. When cholangiography showed papillary polypoid filling defects, 8 of the 14 resected patients showed T1 stage tumor histologically. CONCLUSIONS: In this study, 57% (8/14) of resected patients with papillary polypoid filling defects showed T1 stage tumor. No T1 stage tumor showed stenosis or diffuse sclerosis.

Adult↗
PubMed2001

Looping technique for transpapillary selective biopsy of the left hepatic duct.

PURPOSE: Because biopsy forceps tend to turn towards the right hepatic duct during endoscopic retrograde cholangiopancreatography (ERCP), selective access to the left hepatic duct is difficult. METHODS: In this study, we managed to insert biopsy forceps selectively into the left hepatic duct, by using a looping technique, in three patients. Biopsy forceps were inserted into the right hepatic duct by the conventional method. The elevator of the endoscope was kept down, and the shaft of the biopsy forceps was then advanced to the duodenal cavity until it formed a loop between the endoscope and the papilla. During the procedure, the tip of the forceps was kept at the hepatic hilus. RESULTS: In this condition, we were able to slowly rotate the tip of the forceps and direct the forceps towards the left. Sufficient material from the left hepatic duct was obtained in all patients. CONCLUSIONS: The looping technique was useful for selective access to the left hepatic duct.

Adult↗
PubMed2001

Transpapillary intraductal US prior to biliary drainage in the assessment of longitudinal spread of extrahepatic bile duct carcinoma.

BACKGROUND: The utility of intraductal US via the transpapillary route prior to biliary drainage in the assessment of longitudinal extension of extrahepatic bile duct carcinoma was investigated. METHODS: In 19 patients with extrahepatic bile duct carcinoma who underwent surgical resection, an ultrasonic probe (diameter, 2.0 mm; frequency, 20 MHz) was inserted into the bile duct via the transpapillary route prior to biliary drainage. Longitudinal cancer extension along the bile duct was prospectively determined and compared with the histologic findings in the resected specimens. RESULTS: Results on the hepatic side were as follows: Intraductal US demonstrated more extensive longitudinal cancer spread than cholangiography in 9 of 19 patients with one instance of overdiagnosis. The accuracy of intraductal US in assessing the extent of spread (84%) was superior to that of cholangiography (47%) (p < 0.05). Results on the duodenal side were as follows: In patients with suprapancreatic bile duct cancer (n = 14), intraductal US demonstrated more extensive longitudinal cancer spread than cholangiography in 8 of 14 patients. The accuracy of intraductal US in assessing the extent of the spread (86%) was superior to that of cholangiography (43%) (p < 0.05). CONCLUSIONS: Transpapillary intraductal US prior to biliary drainage is useful in demonstrating longitudinal extension of bile duct cancer. However, the surgical margins were inaccurate in some patients.

Aged↗
PubMed2001

Triterpenoids from Adiantum caudatum.

Three triterpenoids, 8alpha-hydroxyfernan-25,7beta-olide, 3alpha-hydroxy-4alpha-methoxyfilicane and 19alpha-hydroxyferna-7,9(11)-diene were isolated from the fresh fronds of Adiantum caudatum. Their structures were elucidated by spectroscopic techniques. Thirteen known triterpenoids were also identified from this fern.

Ferns↗
PubMed2001

Microbial-ecological significance of sulfide precipitation within anaerobic granular sludge revealed by micro-electrodes study.

Micro-electrodes were applied to anaerobic granular sludge, which was developed in a UASB reactor, to examine intra-granule profiles with respect to pH, glucose and sulfide. When glucose was employed as a bulk liquid substrate, the micro-electrodes study demonstrated the pH behavior along granule depth: pH decrement at the granule exterior portion due to acid formation (buildup of acidity), and subsequent pH increment at the granule inner portion due to the consumption of acid (buildup of alkalinity). Sulfide micro-electrode proved sulfate reduction that mostly occurred at the granule exterior portion. Chemical equilibrium consideration evidently explained the occurrence of ferric sulfide predominantly in the interior portion, which accounts well for the morphology of a representative double-layered structure of granules grown on a low level of sulfite. Inorganic elements distribution within anaerobic granule was examined by electron probe X-ray micro analysis (EPMA) and ICP methods. The presence of crystalline calcium carbonate (calcite) was identified by X-ray diffraction analysis.

Bacteria, Anaerobic↗
PubMed2001

Formation of bioorganic compounds in simulated planetary atmospheres by high energy particles or photons.

Various types of organic compounds have been detected in Jupiter, Titan, and cometary coma. It is probable that organic compounds were formed in primitive Earth and Mars atmospheres. Cosmic rays and solar UV are believed to be two major energy sources for organic formation in space. We examined energetics of organic formation in simulated planetary atmospheres. Gas mixtures including a C-source (carbon monoxide or methane) and a N-source (nitrogen or ammonia) was irradiated with the followings: High energy protons or electrons from accelerators, gamma-rays from 60Co, UV light from a deuterium lamp, and soft X-rays or UV light from an electron synchrotron. Amino acids were detected in the products of particles, gamma-rays and soft X-rays irradiation from each gas mixture examined. UV light gave, however, no amino acid precursors in the gas mixture of carbon monoxide, nitrogen and nitrogen. It gave only a trace of them in the gas mixture of carbon monoxide, ammonia and water or that of methane, nitrogen and water. Yield of amino acid precursors by photons greatly depended on their wavelength. These results suggest that nitrogen-containing organic compounds like amino acid precursors were formed chiefly with high energy particles, not UV photons, in Titan or primitive Earth/Mars atmospheres where ammonia is not available as a predominant N-source.

Alanine↗
PubMed2001

The efficacy of glycolic acid for treating wrinkles: analysis using newly developed facial imaging systems equipped with fluorescent illumination.

The clinical characteristics of photodamaged skin, such as coarse and fine wrinkling, can not be quantitatively evaluated from ordinary photographic records. The purpose of this study was to assess the efficacy of glycolic acid (GA) peeling on facial wrinkling, using computer assisted image analysis. This was accomplished with reproducible imaging techniques, which allowed precise repositioning of the subject's face in front of the camera. Two parameters, the change in wrinkle number and the change in wrinkle length were assessed. Although the clinical improvement of wrinkles correlated with both parameters, wrinkle length more precisely reflected the degree of clinical wrinkles, because the wrinkle number appeared to increase as some shallow wrinkles divided into multiple smaller wrinkles during their improvement. Comparison of responses by different age groups showed that the reduction of total wrinkle length was observed in the order of: 50s>30s and 40s>60s>over 70>under 30. The lack of response by subjects over 70 might be due to the nature of their wrinkles being mainly coarse wrinkles rather than fine ones. We next compared the effect of GA by concentration (35, 50 or 70%), but found no significant differences. As the concentration of GA used for treatment was determined by each subject's erythema reaction, our present result suggests that erythema elicited by GA correlates with improvement of wrinkles and that these two phenomena can be induced by a common pathway of GA treatment. This quantitative analysis clearly shows the efficacy and limitation of GA treatment of wrinkles, and might help to disclose the precise mechanisms of GA effects on the skin structure and function.

Adult↗
PubMed2001

A long-term lifetime amperometric glucose sensor with a perfluorocarbon polymer coating.

We have developed an amperometric glucose sensor whose electrodes are coated with a four-layered membrane: 3-aminopropyltriethoxysilane (gamma-APTES), Nafion, glucose oxidase (GOX), and perfluorocarbon polymer (PFCP). Tests demonstrate the sensor's ability to accurately and successively determine glucose concentrations ranging from 2.8 to 167 mM, over a 66 day period with no increase in response time, while remaining imperviousness to the effects of interference species (2.8 mM ascorbic acid, 0.3 mM uric acid, 0.3 mM p-acetaminophen). Furthermore, tests on diabetic urine samples showed an excellent correlation coefficient of 0.985 (y=1.04x+4.73, n=30) between sensor results and those of Glucose-Dehydrogenase clinical laboratory analyses.

Biosensing Techniques↗
PubMed2001

Comparison of intraductal ultrasonography with percutaneous transhepatic cholangioscopy for the identification of residual bile duct stones during lithotripsy.

BACKGROUND: An imaging modality that can be used to identity small stones after a biliary lithotripsy is required. Intraductal ultrasonography was evaluated by using percutaneous transhepatic cholangioscopy as the gold standard. METHODS: Lithotripsy, under percutaneous transhepatic cholangioscopy guidance, was performed in 20 patients. A thin-caliber ultrasonic probe (2.0 mm in diameter and 20 MHz frequency) was inserted into the bile duct through the percutaneous tract after lithotripsy, and residual stones were identified. This was followed by percutaneous transhepatic cholangioscopy. RESULTS: In the extrahepatic bile ducts, intraductal ultrasonography provided images of all the stones demonstrated on cholangioscopy (n = 11). The sensitivity was superior to that of cholangiography (P < 0.005). However, in the intrahepatic bile ducts, intraductal ultrasonography only visualized the stones located in the cannulated lobe. Extrahepatic stones smaller than 5.0 mm in diameter or in a common hepatic duct larger than 15.0 mm in diameter were missed by cholangiography, but were visualized by the use of intraductal ultrasonography (P < 0.05). CONCLUSIONS: Intraductal ultrasonography is equivalent to cholangioscopy in the extrahepatic bile ducts. Cholangiography and intraductal ultrasonography should be used in combination to image intrahepatic and extrahepatic stones.

Aged↗
PubMed2001

Epinephrine irrigation for the prevention of pancreatic damage after endoscopic balloon sphincteroplasty.

BACKGROUND AND AIM: Endoscopic balloon sphincteroplasty (EBS) is an alternative to sphincterotomy for the treatment of bile duct stones. The purpose of this study was to determine if epinephrine irrigation of the papilla can prevent the pancreatic damage associated with EBS. METHODS: A total of 173 patients with bile duct stones were treated by EBS. After conventional endoscopic retrograde cholangiography, EBS was performed by using a biliary dilatation catheter (balloon diameter: 8 mm). The duct was then cleared by using Dormia baskets or retrieval balloon catheters. Mechanical lithotripsy was performed before extraction when the stones were greater than 8 mm in diameter. In 81 patients, the dilated orifice was irrigated with 40-120 mL (50 +/- 37 mL) of 1:1,000,000 epinephrine (epinephrine group). In the remaining 92 patients, epinephrine irrigation was not performed (control group). Acute pancreatitis was defined by a serum amylase concentration fivefold greater than the upper limits of normal in association with abdominal pain. RESULTS: After EBS, serum amylase concentrations were significantly increased in both groups. However, the degree of hyperamylasemia was less in the epinephrine group than in the control group (617 +/- 611 vs 1037 +/- 1491 IU/L, P < 0.05). The incidence of pancreatitis was lower in the epinephrine group than in the control group (1.2 vs 7.6%, P < 0.05). CONCLUSIONS: Epinephrine irrigation is a simple and useful method to prevent post-EBS pancreatic damage and pancreatitis.

Adult↗
PubMed2001

Intraductal ultrasonography for hepatocellular carcinoma with tumor thrombi in the bile duct: comparison with polypoid cholangiocarcinoma.

BACKGROUND AND AIM: Tumor thrombi in the bile duct caused by hepatocellular carcinoma (HCC), and cholangiocarcinoma show polypoid lesions on cholangiographic findings. This study prospectively compared the images of intraductal ultrasonography between HCC and polypoid cholangiocarcinoma. METHODS: In five patients with tumor thrombi in the bile duct caused by HCC, a 2.0 mm diameter ultrasonic probe with a frequency of 20 MHz was inserted into the bile duct via the transpapillary route (n = 4) or the transhepatic route (n = 1). The images were compared to that of 65 patients with cholangiocarcinoma. RESULTS: In all patients with HCC, intraductal ultrasonography showed a 'polypoid tumor with a narrow base'. In 16 of 65 patients with cholangiocarcinoma, it showed a 'polypoid tumor with a narrow base'. When intraductal ultrasonography showed a 'polypoid tumor with a narrow base', the findings of a positive 'nodule within a nodule' (40 vs 0%; P < 0.05), and the absence of a 'papillary-surface pattern' (80 vs 13%; P < 0.05) were more highly associated with tumor thrombi caused by HCC than to polypoid-type cholangiocarcinoma. CONCLUSIONS: Intraductal ultrasonography was useful to distinguish between tumor thrombi caused by HCC and polypoid-type cholangiocarcinoma.

Aged↗