Biomedical subjects

K Taguchi

Publications and source records attributed to K Taguchi.

480 records · Page 27Linked to original sources

PubMedDate not supplied

Reliability of slow vertex response audiometry in young children with sensorineural hearing loss.

In order to supplement our previous report on the reliability and validity of slow vertex response (SVR) audiometry, the detectability of the response, the agreement among scorers and test-retest reliability were studied in 6 children aged 2-4 years who have sensorineural hearing loss of 60-75 dB for the test frequency (1 000 Hz). Mean percentage of positive response increased from 20.6 to 62.2% as stimulus intensity was increased from 60 to 80 dB. Such a sharp increase in the detectability of the response at a level of stimulus intensity close to the auditory threshold of the subjects was not observed in normal children. The results indicate that SVR audiometry is more reliable and valid in children with sensorineural hearing loss than in normal children.

Acoustic Stimulation↗

PubMedDate not supplied

Risk factors of the recurrence of hepatocellular carcinoma originating from residual cancer cells after hepatectomy.

BACKGROUND/AIMS: Little has been documented to differentiate between recurrence originating from microscopic residual tumor cells and recurrence due to metachronous multicentric origin of hepatocellular carcinoma (HCC). The aim of this study was to clarify the risk factors of HCC recurrence closely related to residual tumor cells. METHODOLOGY: A retrospective review of hepatic resections for HCC during the period between April 1985 and April 1997 was undertaken at a University Hospital with a long history of hepatectomy for HCC. Three hundred and thirteen HCC patients without any definite multicentric recurrence, who underwent hepatectomy, were retrospectively investigated. Main outcome measures were: (Study 1) Risk factors for recurrence were univariately and multivariately investigated among various clinicopathological variables, including the vi factor as a new indicator of the potential malignancy of HCC (i.e., the presence of both microscopic portal vein invasion and intrahepatic metastasis). (Study 2). The risk factors for recurrence were then analyzed according to the period of recurrence. RESULTS: (Study 1) Independent risk factors were: (tumor factors) a positive vi factor, alpha-fetoprotein > 100 ng/ml, and poorly differentiated histology; (host factors) albumin < 3.8 g/dl, the presence of diabetes mellitus, platelet count < 14 x 10(4)/microliter, Y-globulin fraction > 20%. In those risk factors, the relative risk of the vi factor (2.6) was the largest. (Study 2) Within 1 year after hepatectomy, only tumor factors, including the vi factor and poorly differentiated histology, were significant risk factors, tumor factors were significant only up to 2 years after hepatectomy, and thereafter only host factors were significant. CONCLUSIONS: The risk factors for non-multicentric recurrence of HCC are considered to be a positive vi factor, alpha-fetoprotein, and poorly differentiated histology, and the vi factor is considered to be a new prognostic indicator expressing the potential malignancy of HCC such as invasion and metastasis.

Carcinoma, Hepatocellular↗

PubMedDate not supplied

Clinicopathological characteristics of surgically resected minute hepatocellular carcinomas.

BACKGROUND/AIMS: The multistep development of overt hepatocellular carcinoma from very well-differentiated early hepatocellular carcinoma, and of early hepatocellular carcinoma from adenomatous hyperplasia has been strongly suggested. The clinicopathologic and immunohistochemical characteristics of solitary minute hepatocellular carcinomas smaller than 1 cm in size have yet to be clarified. METHODOLOGY: Fourteen minute hepatocellular carcinomas were divided into 2 groups consisting of: 1) hepatocellular carcinoma of hepatitis B surface antigen positive patients (B-HCC) (n = 5), and 2) hepatocellular carcinoma of hepatitis C virus antibody positive patients (C-HCC) (n = 9), then they were all analyzed histopathologically and clinicopathologically. Immunohistochemical studies were also performed using the antibodies against p53 protein. RESULTS: Six of the 14 minute hepatocellular carcinoma were demonstrated to be moderately or poorly differentiated tumors. Among the 8 well-differentiated minute hepatocellular carcinomas, 2 tumors already contained less differentiated components. B-HCC tended to be less differentiated than C-HCC (P < 0.05). Adenomatous hyperplasia was detected in only 2 cases of C-HCC. Small cell liver dysplasia was detected significantly more frequently in C-HCC than in B-HCC (P < 0.05). The prognosis of the 14 minute hepatocellular carcinomas varied considerably. Immunohistochemically, some tumor cells were positive for p53 in 3 cases. CONCLUSIONS: Our study suggests that 1) the multistep carcinogenesis through adenomatous hyperplasia may not be so frequent, 2) De novo carcinogenesis from not only well-differentiated hepatocellular carcinoma, but also from less differentiated hepatocellular carcinoma, especially B-HCC, may be present, 3) the carcinogenesis in the B-HCC cases may behave differently from that in C-HCC cases, and 4) minute hepatocellular carcinomas demonstrate varying prognoses after hepatectomy.

Adult↗

PubMedDate not supplied

Immunohistochemical detection of cytokeratin 18 and its neo-epitope in human salivary glands and pleomorphic adenomas.

An immunohistochemical method using a monoclonal antibody M30 (MAb M30), which reacts with the product released by the cleavage of cytokeratin 18 (CK18) by activated caspase, was used to investigate the extent of apoptosis in human salivary glands and pleomorphic adenomas. The distribution of CK18 in the salivary glands and adenomas was also determined and compared with that of the product detected by MAb M30. CK18 was detected in the cytoplasm of serous acinar and ductal cells in normal human salivary glands. In pleomorphic adenomas, CK18 was observed mainly in the tumor cells of duct-like structures, but not in those of myxomatous or chondroid tissues. Positive MAb M30 reaction products were found in the cytoplasm of acinar cells in the restricted lobules of normal salivary glands and in the luminal contents of duct-like structures in pleomorphic adenomas. These results suggest that a mechanism which suppresses apoptosis may be linked to the growth of human pleomorphic adenomas.

Adenoma, Pleomorphic↗

PubMedDate not supplied

Characteristics of sarcomatous cholangiocarcinoma of the liver.

BACKGROUND/AIMS: The aim of this study was to clarify the clinicopathological characteristics of intrahepatic cholangiocarcinoma with sarcomatous changes. METHODOLOGY: Four cases of cholangiocarcinoma with sarcomatous change were identified and investigated. The clinicopathological findings, including the results of immunohistochemical staining, were investigated in comparison with those of ordinary cholangiocarcinoma. RESULTS: Two of them exhibited pyrexia as the initial symptom. The serum alkaline phosphatase level in sarcomatous cholangiocarcinoma was significantly lower than that in ordinary cholangiocarcinoma. Both the serum carcinoembryonic antigen and carbohydrate 19-9 level in sarcomatous cholangiocarcinoma also tended to be lower than those in ordinary cholangiocarcinoma. The carcinomatous component of all tumors was mostly poorly differentiated adenocarcinoma. The associated microscopic findings were as follows: lymphocyte infiltration in the tumor, accompanied by both necrosis and extensive lymph node metastases. Three of them predominantly exhibited spindle-shaped sarcomatous changes, whereas the other case predominantly demonstrated pleomorphic-type sarcomatous changes. The sarcomatous area was positive for both vimentin, a mesenchymal marker, and for epithelial markers, furthermore, in 3 of 4 cases, the carcinoma portions were also positive for vimentin. The overall survival curves were not significantly different between the 2 groups, however, no long-term survivor was found in sarcomatous cholangiocarcinoma. CONCLUSIONS: The main characteristics of cholangiocarcinoma with sarcomatous changes are considered to be as follows: 1) often demonstrating pyrexia as a symptom; 2) not always demonstrating remarkable abnormal findings in the laboratory data including tumor markers; 3) histologically showing poorly differentiated adenocarcinoma; and 4) showing a very poor prognosis (especially, in a pleomorphic-type).

Aged↗

PubMedDate not supplied

Small hepatocellular carcinoma with minute satellite nodules.

BACKGROUND/AIMS: To investigate the clinicopathologic characteristics of small hepatocellular carcinoma with minute satellite nodules. METHODOLOGY: We investigated the clinicopathologic characteristics of 131 solitary small (< or = 2.0 cm in diameter) hepatocellular carcinomas including 105 hepatocellular carcinomas without minute satellite nodules and 17 hepatocellular carcinomas with minute satellite nodules smaller than 5 mm, and also discuss the clinical significance. RESULTS: None of the clinical backgrounds of the patients and pathologic features of the main tumor, except for the average of preoperative serum alpha-fetoprotein, were significantly different between the two groups. Firstly, minute satellite nodules demonstrated that the maximum diameter of all minute satellite nodules was 1.5-4.0 mm, secondly, the moderately to poorly differentiated hepatocellular carcinomas had 4 or more minute satellite nodules within 1 cm from the main tumor, while well differentiated hepatocellular carcinomas may have 1 or 2 minute satellite nodules 6 cm or more away, and thirdly, 4 or more minute satellite nodules may present within 1 cm in intrahepatic metastasis cases, while 1 or 2 minute satellite nodules may be present 6 cm or more away from the main tumor in multicentric occurrence cases. CONCLUSIONS: At least 13% of solitary small hepatocellular carcinomas had preoperatively undetectable minute satellite nodules. In case of moderately to poorly differentiated hepatocellular carcinomas, hepatic resection as well as percutaneous ethanol injection should be performed including the surrounding liver tissue at least 1.0 cm from the main nodule. On the other hand, in well-differentiated hepatocellular carcinomas, which may indicate multicentric occurrence, closer observation and careful follow-up after therapy are recommended.

Carcinoma, Hepatocellular↗

PubMedDate not supplied

Effect of athrombogenic therapy, especially high dose therapy of dipyridamole, after prosthetic valve replacement.

In order to prevent thrombo-embolism after prosthetic valve replacement, a high dose therapy with 450 mg/day of Dipyridamole and 3,000 mg/day of Aspirin was carried out for 1 year and 2 months in 91 cases (26 cases with aortic valve replacement, 40 cases with mitral valve replacement and 25 cases with multiple valve replacement). In the treated group, the incidence was 1.9% in cases more than 5 years after valve replacement and 2.9% in cases less than 5 years after valve replacement. In contrast, in the control group of 89 cases (47 cases of aortic valve replacement, 30 cases of mitral valve replacement and 12 cases of multiple valve replacement), the incidence was 9.1% and 14.7%, respectively. Thus, in both time intervals following prosthetic valve replacement the incidence of thrombo-embolism in the treated group was significantly lower than in the control group.

Aortic Valve↗

PubMedDate not supplied

Spontaneous regression of hepatocellular carcinoma--a case report.

We report a 72-year-old man with hepatocellular carcinoma, which showed spontaneous regression. He was diagnosed as having chronic hepatitis type C five years before admission. In January 1998, a liver mass was found by ultrasonography. In February, computed tomography showed a low-density mass, 3.5 cm in diameter in the S5 region. Although liver biopsy was not performed, findings obtained by computed tomography and ultrasonography indicated that the tumor was hepatocellular carcinoma. The levels of alpha-fetoprotein and PIVKA (protein induced by vitamin K antagonist)-II were increased to 1000 ng/mL and 2000 mAU/mL, respectively. The patient was admitted to our hospital in March 1998. At the time, the size of liver mass was reduced to 2.5 cm in diameter on computed tomography, and the tumor markers, alpha-fetoprotein and PIVKA-II, spontaneously decreased to the normal range. We considered that hepatocellular carcinoma of this patient regressed spontaneously. Because it was hard to exclude the possibility that the mass contained residual malignant cells, we resected the mass on April 28, 1998. Microscopically, the resected mass did not contain any malignant cells. The parenchyma surrounding tumor necrosis, which is reflected by severe inflammatory infiltration with lymphocytes, indicates spontaneous regression. Although the precise mechanism regarding spontaneous regression of hepatocellular carcinoma is not fully understood, either ischemia due to rapid growth of the tumor or some inflammatory mechanism may be involved in regression of hepatocellular carcinoma.

Aged↗

PubMedDate not supplied

A tricuspid polyurethane heart valve as an alternative to mechanical prostheses or bioprostheses.

The main disadvantages of today's heart valve prostheses are the need for lifelong anticoagulation for mechanical valves and problems with biodegradation for tissue valves. Therefore, a new valve type devoid of these problems would be a major step forward. In order to evaluate a new valve design made by dipmolding with different PU materials, an animal test series was carried out in which two valves from each material were implanted into the mitral position of growing Jersey calves. The surgical procedure and postoperative catheterization data are presented. The survival times ranged between 127 and 291 days. Organs and explanted valves were examined post mortem according to general pathology standards. Specifically, the valves were histologically examined for calcium deposits and investigated by light microscopy, REM and EDAX. All explanted valves showed calcification and immobilization, but the results suggest that at least two PU materials attain survival times which are far beyond the lifetime of bioprostheses under the same implant conditions, justifying further in vivo studies in adult animals.

Animals↗

PubMedDate not supplied

Basic concept for implantation technique of total artificial heart in humans: a review from cadaver implantations.

To develop the application technique of the total artificial heart in humans, it is important to establish a concept about the implantation procedures. Based on cadaver experiments with various types of prosthetic ventricles, some aspects in solving the surgical difficulties were described. Special interest was directed to the geometric topography, the optimal design of the prosthetic ventricles, and the possible surgical solution. Under consideration of spatial differences, especially from that of experimental animals, a proposal was made to place the left and right artificial ventricle with the goal of avoiding compression of the inflow tract or obstruction of the outflow. The design of the connection parts and the angles of the inflow and outflow tracts of the artificial ventricles is essential for good results.

Cadaver↗

PubMedDate not supplied

Immunologic considerations in the use of cultured porcine hepatocytes as a hybrid artificial liver. Anti-porcine hepatocyte human serum.

Cultured porcine hepatocytes with reasonable metabolic functions are a promising bioreactor for a hybrid artificial liver in the treatment of liver failure. A cytotoxic human serum (t-serum) against cultured porcine hepatocytes was accidentally discovered during preliminary experiments, however, which prompted the authors to study the mechanism of the cytotoxicity and the frequency of occurrence of the cytotoxic sera. Among 103 individual sera examined, seven (6.8%) sera showed cytotoxicity to cultured porcine hepatocytes. T-serum heated at 56 degrees C for 30 min completely lost its cytotoxic activity, but the inactivated cytotoxicity was restored by the addition of rabbit complement to the inactivated t-serum. IgM-depleted t-serum produced by 2-mercaptoethanol treatment abolished the cytotoxicity to porcine hepatocytes. The cytotoxic reactions were therefore thought to be mediated by IgM capable of complement activation. Although IgM binding to porcine hepatocytes was also seen in nontoxic sera, the IgM did not activate complement. This implies differences in hepatocyte surface antigens recognized by IgM from t- and nontoxic sera. Before clinical application of a hybrid artificial liver using cultured porcine hepatocytes, detection of cytotoxic human IgM against porcine hepatocytes is necessary, and the means of eliminating the cytotoxic IgM from the hybrid artificial liver system, or of inactivating complement in the system, will be desirable in cases positive for cytotoxic IgM.

Adult↗

PubMedDate not supplied

Chelating effect of human serum proteins on metal-catalyzed ascorbate radical generation.

Purified human serum albumin and immunoglobulin G (IgG) were investigated for their metal-chelating activity, using ESR spectroscopy. Both copper (Cu2+) and iron ions (Fe3+) enhanced the radical intensity of both sodium ascorbate and sodium 5,6-benzylidene-L-ascorbate (SBA). Albumin significantly reduced the stimulation effect of copper, but not that of iron. On the other hand, IgG effectively reduced the radical intensity of iron, without affecting that of copper. The present study demonstrates the specific chelating action of these serum proteins, suggesting their possible preventive effects on metal-catalyzed pathogenic diseases.

Adult↗