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Biomedical subjects

J Yoshino

Publications and source records attributed to J Yoshino.

At least 19 recordsLinked to original sources
PubMed2000

Purification and characterization of membrane-bound hydrogenase from Hydrogenobacter thermophilus strain TK-6, an obligately autotrophic, thermophilic, hydrogen-oxidizing bacterium.

A membrane-bound hydrogenase was purified to electrophoretic homogeneity from the cells of Hydrogenobacter thermophilus strain TK-6, an obligately autotrophic, thermophilic, hydrogen-oxidizing bacterium. Solubilization and purification were done aerobically in the presence of Triton X-100. Three chromatography steps were done for purification; Butyl-Sepharose, Mono-Q, and Superose 6, in this order. Purification was completed with 6.73% yield of total activity and with 21.4-fold increase of specific activity when compared with the values for the membrane fraction. The purified hydrogenase was shown to be a tetramer with alpha2beta2 structure, with a molecular mass of 60,000 Da for the large subunit and 38,000 Da for the small subunit. The purified hydrogenase directly reduced methionaquinone with an apparent Km of around 300 microM and with a turnover number around 2900 (min(-1)). Metal analysis and EPR properties of the hydrogenase have shown that the enzyme is one of the [NiFe]-hydrogenases. Also, optimum pH and temperature for reaction, thermal stability, and electron acceptor specificity were reported. Finally, a model is presented for energy and central metabolism of H. thermophilus strain TK-6.

Amino Acid Sequence↗
PubMed2000

[Studies of gastric acid secretion and gastric mucosal change after Helicobacter pylori eradication--the short and long-term observation].

We studied the gastric acid secretion and the histological findings of gastric mucosa in 48 patients with peptic ulcer before and after successful Helicobacter pylori (H. pylori) eradication. The pH of fasting gastric juice significantly decreased from 2.46 to 1.65 four weeks after eradication (p < 0.001). The factors such as disease, atrophic border, inflammatory cell involvement and histological atrophy were analyzed by logistic regression. Only the atrophic border was a significant and independent factor to convert the acidity after eradication, and the pH of gastric juice prominently decreased in the patients with widespread atrophic mucosal area. In the 24-hour intragastric pH monitoring, the pH3 holding time overnight remarkably decreased from 54.1% to 22.3% after eradication (p < 0.005). In the long follow-up of 17 patients (the mean follow-up period was 15.2 months), the pH of gastric juice kept a lower titer of 1.66. The mean atrophic scores in the upper body reduced from 1.5 to 0.9 (p < 0.05). In addition to the functional recovery of parietal cells after eradication, it was considered that the histological improvement of atrophy in oxyntic mucosa was associated with the recovery of pH.

Adult↗
PubMed2000

[Evaluation of chemotherapy for gastric cancer by endoscopic ultrasonography].

We judged the efficacy of chemotherapy using endoscopic ultrasonography (EUS) in 26 cases of gastric cancer. Treatment efficacy was evaluated according to the General Rules for the Gastric Cancer Study, based on the reduction of the largest cross-sectional area of the tumor. A reduction of over 50% was rated as U-PR and a reduction of -25-50% was rated as U-NC. Our findings showed U-PR in 11 cases and U-NC in 15 cases. Three cases initially considered to be NC according to the rules were judged to be U-PR based on EUS findings. Marked therapeutic efficacy in these 3 cases was demonstrated clinically and this was confirmed by EUS findings. Generalized Wilcoxon test showed a significant difference in the cumulative survival rate between U-PR and U-NC cases (p < 0.05). EUS provides an objective means of evaluating the efficacy of chemotherapy in gastric cancer patients, including those with lesions that cannot be evaluated by the General Rules for the Gastric Cancer Study.

Adult↗
PubMed1999

Endoluminal ultrasonography for pancreatic diseases.

Endoluminal ultrasonography was performed on 146 patients with pancreatobiliary diseases by using high-frequency, thin ultrasonic probes, and the usefulness of the new technique in diagnosis of pancreatic diseases was reported. The ultrasound probe could be inserted into the main pancreatic duct in 43 of 46 patients (93.5%), and images of the lesions could be obtained in 42 patients (91.3%). Endoluminal ultrasonography revealed a hypoechoic mass with clear margins and central echogenicity in patients with pancreatic carcinoma. Endoluminal ultrasonography showed normal pancreatic parenchyma as a fine reticular pattern and did not reveal the tumors surrounding the stenosis in patients with focal pancreatitis. Endoluminal ultrasonography in patients with intraductal papillary adenocarcinoma of the pancreas revealed cystic lesions with mural nodules more than 4 mm, mucus echoes, and solid tumors with mixed echo patterns. There were no severe complications, and acute pancreatitis occurred in none of 46 patients, but high-level serum amylase after examination occurred in 5 patients (10.9%). Endoluminal ultrasonography is useful for differential diagnosis in patients with small pancreatic tumors or cystic lesions, especially intraductal papillary tumors of the pancreas. Endoluminal ultrasonography is recommended as a precise examination for the diagnosis of cystic lesions of the pancreas or stenosis of the main pancreatic duct after ERCP and EUS.

Adenocarcinoma, Mucinous↗
PubMed1999

Surface-rendering imaging of gastrointestinal lesions by three-dimensional endoscopic ultrasonography.

BACKGROUND AND STUDY AIMS: In three-dimensional endoscopic ultrasonography (3D-EUS), a surface-rendering method can provide both a surface image and a cross-sectional ultrasonographic image. We evaluated the usefulness of this imaging method for digestive tract lesions. PATIENTS AND METHODS: A total of 30 patients underwent 3D-EUS with surface-rendering using a 3D probe system which arranged individual radial scanning images into 128 points on a computer monitor to outline the surface of a lesion. A complete surface image of the lesion was displayed on the computer monitor using lines obtained from 40 radial scanning images. RESULTS: Surface-rendering images of lesions were similar to endoscopic images. The surface-rendering method permitted precise correlation of two-dimensional images depicting a slice of a lesion with the corresponding surface of the lesion. Unlike conventional endoscopy, this approach permitted observations of lesions at any desired angle. Complete images of lesions were achieved in 14 patients and were half-completed in another five, but could not be obtained in 11 patients: in six the distance between the lesion and the 3D probe was too short to avoid artifacts, while in five the lesion was larger than the longitudinal scanning length of 4 cm or greater than 90 in extent in radial scanning images. Artifacts caused by heartbeat led to irregular images in four patients, including three with esophageal cancer and one with gastric cancer. CONCLUSIONS: Despite some problems, surface-rendering imaging should prove useful for diagnosis, and the method will improve as software is perfected.

Colonic Neoplasms↗
PubMed1999

[Usefulness of DIC-CT in choledocholithiasis].

In order to assess the efficacy of helical CT in drip-infusion cholangiography (DIC-CT) for diagnosis of choledocholithiasis, 82 patients with biliary diseases, including 25 patients with a definite diagnosis of choledocholithiasis obtained by direct cholangiography, were investigated by DIC-CT and EUS. Comparative investigation showed that, of the 25 cases, 94.7% could be imaged by DIC-CT and 87.5% by EUS, with respective sensitivities of 94.7% and 87.5%. The specificities in both cases were 100% and accuracies were 97.8% with DIC-CT and 96% with EUS respectively. Therefore, in diagnosis the choledocholithiasis, DIC-CT displays similar diagnostic efficiency as EUS or ERC, and can be recognized as the non-invasive and useful procedure for pre-operative diagnosis of cholecystolithiasis.

Biliary Tract Diseases↗
PubMed1998

Effect of a monoclonal antibody against interleukin-4 on suppression of antigen-induced arthritis in mice by oral administration of the inducing antigen.

We investigated a role for interleukin-4 (IL-4) in suppression of T-cell-mediated antigen-induced arthritis (AIA) in mice by oral administration of the inducing antigen. For this investigation, a monoclonal antibody (11B11 mAb) that specifically neutralizes IL-4 was employed. AIA was induced by immunization with methylated bovine serum albumin (mBSA) (day 0) followed by intraarticular injection of mBSA into the ankle joint. To induce oral tolerance, mBSA was administered orally once a day from day-5 to-1. The 11B11 mAB was injected i.p.. 30 min before each oral administration of mBSA. Oral administration of mBSA resulted in marked suppression of AIA. Suppression of the joint inflammation of the oral antigen was significantly diminished by treatment with 11B11 mAb. The mAb treatment was also followed by blockade of suppression of proliferative responses of lymphoid cells to mBSA by oral antigen. Furthermore, secretion of IL-4 was significantly increased following oral administration of mBSA and the increased IL-4 secretion was markedly reduced by treatment with 11B11 mAb. There was a decrease in production of IFN-gamma in orally tolerized mice that was blocked by the IL-4-neutralizing mAb. Thus, treatment with an anti-IL-4-mAb appears to be effective in blocking suppression of AIA by oral administration of the inducing antigen. The results also suggest that IL-4 may play a role in down-regulation of T-cell-mediated inflammation by feeding pathogenic antigens.

Administration, Oral↗
PubMed1998

Enhancement of T-cell-mediated arthritis in mice by treatment with a monoclonal antibody against interleukin-4.

We investigated a role for interleukin-4 (IL-4) in T-cell-mediated arthritis by employing a monoclonal antibody against IL-4 (11B11 mAb). As a model of T-cell-mediated arthritis, antigen-induced arthritis (AIA) in mice was used. To induce AIA, mice were immunized with methylated bovine serum albumin (mBSA) (day 0). On day 14, the animals were intraarticularly injected with mBSA into the ankle joint. 11B11 mAb was daily injected i.p. for a period of 10 days, commencing on the day of immunization with mBSA. We found that treatment with 11B11 mAb significantly enhanced the severity of AIA. The enhanced arthritis was also observed in mice injected i.v. with lymphoid cells from mBSA-immunized mice, followed by the intraarticular challenge injection of mBSA. The enhancement of AIA by the anti-IL-4 mAb was associated with a significant increase in the proliferative response of lymphoid cells to mBSA in mice treated with the mAb. The secretion of IL-4 as well as IL-5 decreased in 11B11 mAb-treated mice, while the production of IFN-gamma and IL-2 increased following mAb treatment. Thus, the neutralization of IL-4 by an anti-IL-4 mAb appeared to enhance AIA, suggesting a role for IL-4 in downregulating T-cell-mediated joint inflammation.

Adjuvants, Immunologic↗
PubMed1998

Endoscopic MRI.

We used a new magnetic resonance endoscope with a small radiofrequent (RF) coil attached to the tip. After insertion of the instrument into the second portion of the duodenum, patients were placed in a magnetic resonance imaging (MRI) scanner. Fast spoiled gradient-recalled acquisition (SPGR) pulse sequences were used for this method. After plain scans, six axial scans were performed after intravenous injection of 20 ml of gadolinium-diethylenetriaminepentaacetic acid (DTPA) contrast medium. We performed endo-MRI on 22 patients, 13 with pancreatic carcinoma, four with pancreatic cystoadenoma, and five with other diseases. In the patients with pancreatic carcinoma, tumors were delineated as low-intensity masses after injection of contrast medium. Dilated main pancreatic ducts were clearly defined. In eight patients with carcinoma of the head of the pancreas, tumors were clearly defined in seven (87.5%) cases. In the eighth case, motion artifact prevented acquisition of a clear image of the pancreas. For diagnosis of invasion of the portal vein, the sensitivity of endo-MRI was 80%, the specificity was 100%, and overall accuracy was 87.5%. The new technique of endo-MRI allows the precise diagnosis of pancreatic tumors.

Carcinoma↗
PubMed1998

[Diagnosis of the wall-thickened lesions of the gallbladder with dynamic MRI].

We studied 32 patients with the thickened lesions of the wall of the gallbladder by using dynamic MRI. We tried the differential diagnosis of gallbladder lesions according to the time intensity curve (TIC) and enhanced pattern. TIC of carcinoma was elevated more seeply from plain to arterial phase than the inflammatory diseases. The Inflammatory diseases were keeping three-layer structures of the wall of the gallbladder, but gallbladder carcinoma destroys the wall-structure. We could diagnose as direct liver invasion of the carcinoma clearly. We could exactly diagnose adenomyomatosis in dynamic MRI by small low intensity spots within the wall of the gallbladder. In the patients with gall stones, the wall of the gallbladder were more clearly observed in dynamic MRI compared with US and EUS.

Carcinoma, Adenosquamous↗
PubMed1998

[Application of ultrasound method for hemorrhagic digestive disease].

Ultrasonography for the digestive diseases are consisted of abdominal ultrasonography (US), endoscopic ultrasonography (EUS) and color Doppler endoscopic ultrasonography (CDEUS). These play a supplementary role in comparison with the roentgenography and endoscopy. The information of the ultrasonography is different from these examinations. By US the collateral shunts of esophago-gastric varices are observed. EUS is useful for diagnosis of the properties of esophago-gastric varices and judgement of effects of treatment for these varices, gastric ulcer and vessels in ulcer base and hemorrhagic bowel diseases. CDEUS can show blood streams of esophago-gastric varices and hemorrhagic ulcer.

Duodenal Ulcer↗
PubMed1997

Three-dimensional intraductal ultrasonography: preliminary results of a new technique for the diagnosis of diseases of the pancreatobiliary system.

BACKGROUND AND STUDY AIMS: Intraductal ultrasonography (IDUS) is a useful method for the diagnosis of pancreatobiliary diseases, but the images obtained using the presently available ultrasonic probes are limited by their two-dimensional nature and are sometimes difficult to interpret. The possible application of three-dimensional intraductal ultrasonography (3 D-IDUS) to facilitate the diagnosis of pancreatobiliary disease was therefore studied using a newly developed system. PATIENTS AND METHODS: 3 D-IDUS of the biliary system was performed on 26 patients with benign (n = 100) or malignant pancreatobiliary diseases (n = 16), via percutaneous transhepatic or peroral approaches. Three-dimensional diagnoses were made using both radial and linear images generated on the monitor of this system along with a comparison with conventional IDUS (2 D-IDUS) findings. RESULTS: The courses of vessels surrounding the bile duct could be easily imaged in all cases, and accurate assessment of tumor extension and the relationship with surrounding organs could be achieved for all the malignancies. In four of six cases of bile duct cancers the whole outline of the tumor could be visualized so that the tumor volumes could be measured. CONCLUSIONS: These preliminary results of 3 D-IDUS in the pancreatobiliary system, the first to be reported in the English literature, indicate that this new system has clear advantages over the 2 D-IDUS approach for diagnostic purposes. Further technical improvements can be expected which will ensure a clinical role for 3 D-IDUS.

Adult↗
PubMed1997

[The studies of extracorporeal shock wave lithotripsy (ESWL) for pancreatic ductal stones].

30 patients with main pancreatic duct stones were treated by ESWL. In 18 of 22 patients who had not previously undergone endoscopic pancreatic sphincterotomy (EPST) or endoscopic sphincterotomy (EST), the stone fragments disappeared after ESWL. The fragments were removed endoscopically in the remaining 4 cases. Complete clearance was achieved in 8 cases with endoscopically unextractable stones by ESWL. After the ESWL procedure, absolute relief from pain was reported by in 19 of 22 patients with abdominal complaints. Serum amylase levels decreased significantly, and dilatation of the main pancreatic duct (MPD) was reduced. In the medium-term follow-up period, pancreatic exocrine function and endocrine function had a possibility to be preserved. One case of pancreatic cancer and one case of an intraductal papillary tumor of the pancreas were found, indicating that careful observation is necessary even after complete removal of pancreatic stones. In cases of Santorini duct dominant, multiple stones, or stricture of the MPD, ESWL should be combined with EPST and endoscopic stenting for preventing recurrence of acute pancreatitis and pancreatic stones. In conclusion, ESWL is the first choice of treatment for pancreatolithiasis and useful procedure and the limited complications.

Adult↗