Biomedical subjects
Publications and source records attributed to A Ohashi.
A case of symptomatic duodenal duplication cyst is reported. The patient underwent endoscopic partial resection of the cystic wall using the O-ring ligation kit. After resection, the abdominal pain disappeared. Endoscopic partial resection is useful for diagnosis and treatment of duodenal duplication cyst.
BACKGROUND: Transpapillary procurement of bile duct biopsy specimens is an effective diagnostic technique in cases of biliary structure. The utility of new ropeway-type bile duct biopsy forceps with a side slit for a guidewire was investigated in this study. METHODS: The 12 patients in this study had bile duct cancer (n = 3), cancer of the head of the pancreas (n = 4), gallbladder cancer (n = 1), and benign bile duct stenosis (n = 4). After endoscopic retrograde cholangiography, a guidewire was placed in the bile duct across the stenosis. The new forceps (1.8-mm diameter clamshell-type biopsy forceps without needle) was then introduced through the intact papilla along the guidewire. RESULTS: In all patients, sufficient tissue for histopathologic evaluation was obtained without complication. In one patient, biopsy specimens were selectively obtained of the left hepatic duct, which was impossible with conventional forceps. In another patient, histologic examination of specimens obtained by using this new forceps showed adenocarcinoma, whereas specimens obtained with a conventional forceps did not contain adenocarcinoma. However, in another patient, biopsy specimens obtained with a conventional forceps contained adenocarcinoma that was not evident in specimens obtained with the new forceps. Dislodgement of the guidewire during procurement of biopsy specimens occurred in 1 patient. In the other 11 patients, an endoscopic biliary drain was inserted over the guidewire. CONCLUSION: The new ropeway-type biopsy forceps is useful for selectively obtaining biopsy specimens of the bile duct. With this system, access for subsequent endoscopic biliary drainage is maintained.
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In the present study, the sequential expression and cellular localization of cyclin B1 was examined in two-cell mouse embryos to elucidate the mechanism of the two-cell block. One-cell embryos derived from in vitro fertilization were cultured with oviductal tissue (nonblocking condition) or without oviductal tissue (blocking condition) to establish the experimental conditions in which the embryos either overcome the two-cell block or do not. The amount of cyclin B1 gradually increased through the second cell cycle (through S to G2 phase). However, the difference was not observed between culture conditions. This showed that even embryos exhibiting the two-cell block normally synthesize cyclin B1 through the cell cycle. Cyclin B1 in embryos cultured under nonblocking condition accumulates in the nucleus during the transition from the G2 to the M phase, whereas that in embryos cultured in blocking condition localizes in the cytoplasm throughout the cell cycle. These data indicate that two-cell embryos cultured in blocking condition are able to normally synthesize cyclin B1 but have defects in nuclear accumulation of the protein. However, when two-cell blocked embryos were treated with okadaic acid, an activator of Cdc2 kinase, part of cyclin B1 in the embryos translocated into the nucleus. Moreover, treatment with butyrolactone I, a specific inhibitor of Cdc2 kinase, inhibits nuclear translocation of cyclin B1 in those embryos. These results suggest that Cdc2 kinase regulates the nuclear accumulation of cyclin B1 in mouse two-cell embryos.
We previously showed that very thin filamentous bacteria affiliated with the division green non-sulfur bacteria were abundant in the outermost layer of thermophilic methanogenic sludge granules fed with sucrose and several low-molecular-weight fatty acids (Y. Sekiguchi, Y. Kamagata, K. Nakamura, A. Ohashi, H. Harada, Appl. Environ. Microbiol. 65:1280-1288, 1999). Further 16S ribosomal DNA (rDNA) cloning-based analysis revealed that the microbes were classified within a unique clade, green non-sulfur bacteria (GNSB) subdivision I, which contains a number of 16S rDNA clone sequences from various environmental samples but no cultured representatives. To investigate their function in the community and physiological traits, we attempted to isolate the yet-to-be-cultured microbes from the original granular sludge. The first attempt at isolation from the granules was, however, not successful. In the other thermophilic reactor that had been treating fried soybean curd-manufacturing wastewater, we found filamentous microorganisms to outgrow, resulting in the formation of projection-like structures on the surface of granules, making the granules look like sea urchins. 16S rDNA-cloning analysis combined with fluorescent in situ hybridization revealed that the projections were comprised of the uncultured filamentous cells affiliated with the GNSB subdivision I and Methanothermobacter-like cells and the very ends of the projections were comprised solely of the filamentous cells. By using the tip of the projection as the inoculum for primary enrichment, a thermophilic, strictly anaerobic, filamentous bacterium, designated strain UNI-1, was successfully isolated with a medium supplemented with sucrose and yeast extract. The strain was a very slow growing bacterium which is capable of utilizing only a limited range of carbohydrates in the presence of yeast extract and produced hydrogen from these substrates. The growth was found to be significantly stimulated when the strain was cocultured with a hydrogen-utilizing methanogen, Methanothermobacter thermautotrophicus, suggesting that the strain is a sugar-fermenting bacterium, the growth of which is dependent on hydrogen consumers in the granules.
Uncoupling protein (UCP) is a transporter family present in the mitochondrial inner membrane, and as its name suggests, it uncouples respiration from ATP synthesis by dissipating the transmembrane proton gradient as heat. UCP is now recognized as a key molecule in metabolic thermogenesis such as cold- and diet-induced heat production, which is a significant component of energy expenditure, and its dysfunction contributes to the development of obesity. Among the UCP family, UCP-1 is expressed exclusively in brown adipose tissue (BAT), while UCP-2 is present in many organs and UCP-3 is in skeletal muscle. BAT thermogenesis by UCP-1, which has been studied most extensively, is controlled directly by sympathetic nerves principally through the beta-adrenergic action of norepinephrine. Since the beta 3-adrenoceptor is present primarily in adipose tissues, its selective agonists stimulate BAT thermogenesis and also lipid mobilization in white adipose tissue without any noticeable effect on beta 1- and beta 2-adrenoceptos. Therefore, beta 3-adrenoceptor agonists would be promising for the pharmacotherapy of obesity. UCP gene expression is up regulated by ligands for nuclear receptors such as thyroid hormone receptor, peroxisome proliferator-activated receptors (PPAR) and retinoid-X receptor. Long chain fatty acids and some of their metabolites are known to activate PPAR and thereby lead to abundant expression of UCP, which may also contribute to increase in energy expenditure and prevention of obesity. The activity of UCP is suppressed by purine nucleotides but activated by fatty acids. Thus, fatty acids increase UCP-mediated thermogenesis by direct activation of UCP and also by increased gene expression, implying some specific fatty acids or their derivatives as an effective anti-obesity tool.
A 49-year-old man was referred to our hospital for the treatment of gallstones in 1993. Bilateral adrenal nodular masses were detected incidentally by abdominal computed tomography. He had no clinical signs of Cushing's syndrome such as central obesity, striae of skin and diabetes mellitus. We performed cholecystectomy and partial adrenalectomy of right adrenal gland as a biopsy, and diagnosed him as preclinical Cushing's syndrome due to adrenocorticotropin-independent bilateral adrenal macronodular hyperplasia (AIMAH) based on endocrinological and histological examinations. We followed him up for 7 years. During the observation period, the sizes of both adrenal glands increased gradually, and finally serum cortisol level increased beyond normal range, and he showed a Cushingoid appearance such as moon face and central obesity. His skin became atrophic and very fragile, and the bone mineral density of his lumbar spine was extremely low. Serum cortisol level was elevated, and plasma ACTH level was always suppressed. Urinary excretion of 17-hydroxycorticosteroid and free cortisol were increased. Diurnal rhythm of cortisol and ACTH was completely lost and high dose (8 mg/day) dexamethasone did not suppress urinary 17-hydroxycorticosteroid excretion. He became clinically overt Cushing's syndrome. We recommended total adrenalectomy, but he refused it. It is important to know the natural history of preclinical Cushing's syndrome due to AIMAH when choosing an adequate treatment.
The centrifugal liquid membrane (CLM) method, designed for the rapid sample injection, was applied to the kinetic study of the complexation of palladium(II) with 2-(5-bromo-2-pyridylazo)-5-diethyaminophenol (5-Br-PADAP) in the heptane/water system. The formation rates of Pd(II)-5-Br-PADAP complex, which existed only at the heptane/water interface, could be directly measured by the CLM method combined with transmission spectrophotometry. We found that the formation rates of Pd(II)-5-Br-PADAP complex were accelerated by the protonation of 5-Br-PADAP at the diethylamino-group that did not coordinate to Pd(II) ion and that the rate constant for the reaction of protonated 5-Br-PADAP at the interface was close to that in the aqueous phase. The present study demonstrated that the CLM method was easily applicable for the measurements of relatively fast interfacial reactions.
OBJECTIVE: We clarified the number of biopsies required to determine malignancy of the biliary tract on the basis of the type of bile duct tumor. SUBJECTS AND METHODS: Patients with a biliary tract malignancy (n = 33) and a benign biliary stenosis (n = 3) underwent biopsy via the percutaneous transhepatic route. We performed intraductal sonography using a 20-MHz probe with a 2.0-mm diameter. The sonographic findings were prospectively classified as polypoid, circular, or semicircular. The tip of a long 9-French sheath with a side port was wedged into the stenosis, and six specimens were obtained with a 1.8-mm-diameter forceps with serrated cups. RESULTS: When cholangiography or intraductal sonography showed a polypoid lesion, the sensitivity of two biopsies was 100% (6/6). When cholangiography showed a stenotic lesion, the sensitivity of nine biopsies (96%, 26/27) was superior to that of two biopsies (74%, 20/27; p < 0.05). When intraductal sonography showed a circular lesion, the sensitivity of three biopsies (100%, 14/14) was superior to that of a single biopsy (64%, 9/14; p < 0.05). When it showed a semicircular lesion, the sensitivity of nine biopsies (92%, 12/13) was superior to that of two biopsies (54%, 7/13; p < 0.05). CONCLUSION: Bile duct biopsy using a sheath with a side port has a high sensitivity. However, the number of biopsies required depends on the cholangioscopic and intraductal sonographic appearance of the tumor.
A thermophilic UASB reactor was operated at 55 degrees C for greater than 470 days in order to investigate the effects of feed composition on the changes in microbial community structure where thermophilic granular sludge was used as the inoculum source. The feed compositions were changed with cultivation days; phase 1 (1-70 days), alcohol distillery wastewater; phase 2 (71-281 days), artificial acetate wastewater; phase 3 (282-474 days), artificial sucrose wastewater. During the first one month of each phase, the methanogenic activity and cell density of methanogens quantified by fluorescence in situ hybridization (FISH) drastically changed as a result of shift in feed composition. When artificial acetate wastewater was used as feed, retained granular sludge was partially disintegrated due to a decrease in the number of symbiotic bacterial community members: acetogens (acidogens) and hydrogenotrophic methanogens. In contrast, when the feed was shifted to sucrose (phase 3), granulation of biomass was promoted by a remarkable proliferation of the symbiotic community. The presence of hydrogen-utilizing methanogens and acetogens (acidogens) are shown to be effective for the enhancement of thermophilic granulation. The cell density of methanogens determined by FISH was strongly correlated with the methane-producing potential of the retained thermophilic granular sludge.
In order to examine the feasibility of endoscopic microwave coagulation therapy (MCT) for the treatment of common bile duct cancer in humans, we investigated the safety and effectiveness of endoscopic MCT with the assistance of intraductal ultrasonography (IDUS). We performed MCT in the canine small intestine as a model because of its similarity in size to the obstructed human common bile duct. Multiple coagulation lesions were made in anesthetized dogs, with the endoscope inserted through a jejunostomy. Under condition "A", the tip of the MCT probe was kept in a fixed position in contact with the mucosa of the intestine, and coagulation was performed with an output of 30 or 50 W for 30 or 10 s, respectively. Under condition "B", the tip of the MCT probe was moved along the intestinal mucosa, and coagulation was performed with an output of 50, 40, or 30 W, all for 10 s. After coagulation, a thin-caliber ultrasonic probe was inserted endoscopically for observation of the effects of coagulation. Each coagulation under condition "A" resulted in degeneration of all layers of the intestine. Coagulation under condition "B" resulted in more localized degeneration, extending from the mucosal layer to the proper muscle layer. By comparison with histologic observations, the accuracy of IDUS in assessing depth of degeneration was 87.5%. Endoscopic microwave coagulation was considered safe and effective, and IDUS was able to accurately assess the effects of microwave coagulation.
We investigated the utility and limitations of three-dimensional intraductal ultrasonography (3D-IDUS), for the assessment of the extent of longitudinal cancer spread to the hepatic side by extrahepatic bile duct carcinoma. In eight patients with extrahepatic bile duct carcinoma. 3D-IDUS was used to assess longitudinal cancer extension to the hepatic side prior to resection. When the linear dimension of 3D-IDUS showed bile duct wall thickening that was connected to the tumor and which became thin at a point, it was determined to be the front formation of longitudinal cancer extension. The findings were examined in relation to histologic information from the resected specimen. Although 3D-IDUS showed front formation of wall thickening in two patients, it accurately reflected the histological margin of the longitudinal cancer extension in only one patient. In the other patient, the wall thickening was longer than the histological margin. When 3D-IDUS showed bile duct wall thickening without front formation (n = 2), the wall thickening was longer than the histological margin of the longitudinal cancer extension. Even when 3D-IDUS did not show wall thickening (n = 4), one of these patients showed cancer spread histologically. As a result, the accuracy in assessing longitudinal cancer extension by 3D-IDUS was only 50%. Even if the linear dimension of 3D-IDUS demonstrated front formation of thickening of the bile duct, it reflected not only cancer extension but also inflammatory wall thickening.
Percutaneous recanalization of the bile duct is essential for placing biliary stents and carrying out other interventions. This prospective study was performed to establish safe approaches for percutaneous recanalization of the bile duct when it had previously resulted in failure. Between July 1995 and July 1999, percutaneous recanalization of the bile duct was attempted in 58 patients with a malignant biliary stenosis. When recanalization failed, an endoscopic naso-biliary drainage (ENBD) catheter was placed across the stenosis. The procedure was again attempted along the ENBD catheter. In the period of the study, four patients underwent successful recanalization after ENBD, although attempts prior to ENBD had been unsuccessful. As a result, the success rate of recanalization in the period was 100% (58/58). When recanalization fails, the use of an ENBD catheter may provide access to the biliary tree, and the biliary stenosis can be recanalized safely.
We prospectively investigated whether the placement of endoscopic naso-biliary drainage (ENBD) precluded percutaneous transhepatic biliary drainage (PTBD). In 40 patients, the caliber of the intrahepatic bile duct was measured prior to ENBD by ultrasonography. When PTBD was required after ENBD, the ENBD catheter was clamped for 1 to 2 h before PTBD, and its caliber was again measured at the time of PTBD. When PTBD was performed within 7 days (mean, 1.8 days) after ENBD (n = 27), the size of the intrahepatic bile duct was 5.0 +/- 2.3 mm before and 4.6 +/- 2.3 mm after ENBD. There was no significant difference between these values (P > 0.5). When PTBD was performed 8 to 40 days (mean, 17.8 days) after ENBD (n = 13), the bile duct diameter was significantly reduced, from 4.2 +/- 1.5 mm (pre-ENBD) to 1.8 +/- 1.7 mm (post-ENBD) (P < 0.05). When PTBD was conducted within 7 days (mean, 1.8 days) after ENBD, previous ENBD did not induce collapse of the bile duct, if the ENBD catheter was clamped for 1 to 2 h before the puncture of the bile duct.
BACKGROUND: We assessed the local effects of radiation therapy using intraductal ultrasonography (US) to predict the subsequent patency of metallic stents in bile duct carcinoma. METHODS: Data from 16 patients with extrahepatic-suprapancreatic bile duct carcinoma were prospectively analyzed. Thin-caliber US probes (2.0 mm diameter/20 MHz frequency and 2.8 mm diameter/10 MHz frequency) were inserted into the bile duct via a percutaneous transhepatic approach pre- and postradiation therapy to evaluate the effects of treatment. When intraductal US showed a reduction in bile duct wall thickness of 30% or greater or showed a lessening of vessel (portal vein or right hepatic artery) invasion, radiation therapy was judged to be effective. Noncovered metallic stents were then inserted, and their patency was evaluated over time. RESULTS: When radiation therapy was effective (n = 7), the metallic stent was patent for 522 +/- 571 days. When radiation was ineffective (n = 9), the metallic stent was patent for only 188 +/- 159 days. When radiation therapy was ineffective, stent obstruction occurred in 6 of 9 (66.7%) patients during this period, significantly more frequently than when radiation therapy was effective (14.3%, p < 0.05). CONCLUSIONS: Assessment of local radiation effects by intraductal US is useful for predicting patency of metallic stents in bile duct cancer.
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BACKGROUND: We evaluated the utility of the double-catheter method to establish the track for percutaneous transhepatic cholangioscopy (PTCS). METHODS: Dilatation of the percutaneous transhepatic track to 16F for PTCS was attempted in 105 patients. The results were prospectively analyzed. Using the single-catheter method (n = 22), a 16F PTCS catheter was replaced without the inner catheter. Using the double-catheter method (n = 83), a 7F catheter with a balloon tip was inserted through a 16F PTCS catheter. The balloon was located distal to the major duodenal papilla. The double-catheter method was further subclassified as follows: Method 2A (n = 62), the tip of the outer catheter (16F) was not advanced through biliary stenoses; Method 2B (n = 21), the catheter was advanced through biliary stenoses. RESULTS: In the patients treated by the double-catheter method, dislodgement of the catheter did not occur, whereas the single-catheter became dislodged in 18% (p < 0.0005). The morbidity of method 2A (0%) was less than that of method 2B (14%) (p < 0.005). CONCLUSION: The double-catheter method prevents dislodgement of the PTCS catheter. The outer catheter should not be advanced to the biliary stenosis.
BACKGROUND: Percutaneous transhepatic biliary drainage is required for percutaneous transhepatic cholangioscopy. However, puncture of nondilated bile ducts under ultrasonographic guidance is difficult. METHODS: In 10 patients with no ultrasonographic evidence of intrahepatic bile duct dilatation, percutaneous transhepatic biliary drainage was performed under fluoroscopic guidance using cholangiography obtained via a nasobiliary drainage catheter. Direct puncture was performed by means of a left ventral approach using oblique C-arm fluoroscopy. RESULTS: Bile duct puncture was successful in all patients. There were no procedure-related complications. Subsequent cholangioscopy was successful in all patients. CONCLUSIONS: Direct puncture using nasobiliary drainage cholangiography and oblique fluoroscopy is a useful method when cholangioscopy is necessary in patients with nondilated bile ducts.