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Biomedical subjects

H Iwamoto

Publications and source records attributed to H Iwamoto.

316 records · Page 18Linked to original sources
PubMedDate not supplied

Radial flow bioreactor for the creation of bioartificial liver and kidney.

A radial flow bioreactor (RFB) is used for a three-dimensional perfusion culture of hepatocellular carcinoma (HCC) cells and renal cells, to create a bioartificial liver and kidney. The cylindrical reactor is filled with porous cellulose microcarrier. RFB can be characterized as a system in which the medium flows from the periphery toward the center of the reactor, thereby delivering an adequate supply of oxygen and nutrients to cells at the center as well as at the periphery. HCC cells incubated in the RFB system at high density maintained viability for long periods of time. Proximal tubular cells (LLC-PK1) as well as HCC cells, but not human immortalized mesangial cells (HMC) were cultured in the RFB for more than 14 days. The mRNA expression of some enzymes involved in the urea cycle, cytochrome P450s in HCC cells, and the 1-alpha-hydroxylase (CYP27B1) in LLC-PK1 cells was higher than that in monolayer cultures. These results suggest that the RFB system composed of HCC cells or renal cells may be useful for a bioartificial liver and kidney.

Animals↗
PubMedDate not supplied

HER-2/neu expression in ovarian clear cell carcinomas.

HER-2 /neu is a 185-kDa glycoprotein and a transmembrane receptor with tyrosine kinase activity. Its overexpression is observed in 25-30% of primary breast carcinomas and is associated with a poor clinical prognosis. Recently, the U.S. Food and Drug Administration and the Japanese Ministry of Health, Welfare, and Labor approved the use of trastuzumab (Herceptin, Genentech, South San Francisco, CA) for the treatment of patients with metastatic breast carcinomas overexpressing HER-2 /neu. Results of clinical trials with Herceptin suggest that it may prolong the survival of patients with advanced metastatic breast carcinoma. Relatively little is known concerning the relationship between HER-2 /neu status and ovarian clear cell carcinoma. If HER-2 /neu overexpression status were demonstrable in ovarian clear cell carcinoma and a clinical correlation between overexpression and prognosis could be established, a rationale for clinical use of Herceptin for this tumor could be established. Our aim was to evaluate HER-2 /neu status in ovarian clear cell carcinomas. Fifteen ovarian clear cell carcinoma cases were immunostained for HER-2 /neu using HercepTest (DAKO, Glostrup, Denmark). Overexpression of HER-2 /neu was detected in only one case. Unlike in breast carcinoma, HER-2 /neu overexpression appeared to be uncommon in ovarian clear cell carcinomas. Herceptin may thus target only a small proportion of ovarian clear cell carcinomas and be of limited clinical value for treatment of this carcinoma.

Adenocarcinoma, Clear Cell↗
PubMedDate not supplied

Hepatic epithelioid hemangioendothelioma.

Epithelioid hemangioendothelioma (EHE) is a rare neoplasm of vascular origin with unpredictable malignant potential. We describe two patients with primary EHE of the liver and review 34 cases previously published in Japan and compare them with those in Western countries. The clinical aspects of EHE and relevant treatment results in Japanese patients were similar to those found in Western countries, the exception being the matter of difference in incidence between genders. Although this tumor type has been reported to be more frequent among women, there was no significant difference in incidence between men and women. Hepatic EHE generally behaves as a low-grade malignant tumor with a slow progression phenotype; however, this disease seems to be resistant to chemotherapy and to be lethal in some cases. Surgical resection or liver transplantation is recommended after rapid diagnosis by radiologic examination and histologic findings, including positive staining of tumor cells for factor VIII-related antigen.

Adult↗
PubMedDate not supplied

Carcinosarcoma of the urinary bladder: expression of epithelial markers and different expression of heat shock proteins between epithelial and sarcomatous elements.

A case of carcinosarcoma composed of both adenocarcinoma and sarcomatous elements in the non-trigone region of the urinary bladder is presented. The epithelial element was a well to poorly differentiated adenocarcinoma with focal squamous metaplasia. The sarcomatous elements disclosed spindle cell sarcoma with focal epithelioid pattern and myxoid change in the stroma, together with chondrosarcomatous and rhabdomyosarcomatous elements. By immunohistochemical examination, not only the carcinoma element but also the sarcomatous elements showed a positive immunoreaction for cytokeratin (CK), epithelial membrane antigen (EMA) and carcinoembryonic antigen. Some population of sarcomatous elements expressed smooth muscle actin and muscle specific actin (MSA) and a limited portion of epithelioid area showed a positive immunoreaction for desmin, MSA and myoglobin, indicating leiomyosarcomatous and rhabdomyosarcomatous differentiation, respectively. Unexpectedly, tumor cells in the chondrosarcomatous element revealed a simultaneous positivity of CK and EMA as well as S-100 protein. Both epithelial and sarcomatous elements showed an intensive positive immunoreaction for p53 and heat shock protein (HSP) 70. However, HSP27 and HSP60 were detected in most epithelial elements and only in a small number of tumor cells in the sarcomatous area. These findings indicate that sarcomatous elements, including heterologous elements, may derive from epithelial elements with partial or complete loss of epithelial features, and different factors other than p53 and HSP70 may associate with the morphological alteration of carcinoma.

Biomarkers↗
PubMedDate not supplied

Beta-lipoproteins influence the serum level of hepatitis C virus.

Low density lipoprotein receptor (LDLR) has been proposed as a candidate receptor for hepatitis C virus (HCV). According to previous reports, free beta-lipoproteins in a human serum may regulate the rate of hepatocyte infection by competing with the virus. Therefore, serum HCV levels should be regulated by the rise and fall of serum beta-lipoproteins since the infection rate of virions influences HCV replication in hepatocytes and release of virions by hepatocytes. In this study, we examined the relationship between serum beta-lipoproteins and HCV-antigen (Ag) levels in patients with chronic type C hepatitis. Patients were selected based on strict criteria to eliminate other factors that might influence serum HCV levels. Serum concentrations of beta-lipoproteins and HCV-Ag were measured two or more times within 3 months for each patient. The result showed that HCV-Ag levels were negatively correlated with the increased beta-lipoproteins. The results support the concept that LDLR is a HCV receptor and that beta-lipoproteins competitively inhibit the infection of hepatocytes with HCV through the LDLR.

Binding, Competitive↗
PubMedDate not supplied

Analysis of HBs antigen negative variant of hepatitis B virus: unique substitutions, Glu129 to Asp and Gly145 to Ala in the surface antigen gene.

We analyzed the surface gene (S gene) of a hepatitis B virus (HBV) isolate with mutations of envelope protein that rendered it undetectable by both a monoclonal hepatitis B surface antigen (HBsAg) enzyme-linked immunosorbent assay (ELISA) and polyclonal HBsAg radioimmunoassay (RIA). Sequencing of independently cloned products of HBV polymerase chain reaction revealed several point mutations within the S gene. Rare substitution was identified both at positions 129 (glutamine to asparagine) and at position 145 (glycine to alanine) in the 'a' determinant region, which is considered to be within a larger antigenic area known as the major hydrophilic region (MHR). A computer-assisted analysis of protein secondary structure could not find any significant difference between this mutant and wild-type HBsAg. However, the substitution of substitution glycine to alanine at position 129 introduce a putative glycosylation site (Asn-Gly-Thr), which may interfere with the antigenicity of HbsAg. Also, HBV variant with substitution at position 145 (Gly to Ala) has been recently reported to be antigenically altered and to show impaired recognition by polyclonal hepatitis B hyperimmune globulin in vitro. These genetic mutations in the S gene inside MHR may allow to escape detection by standard HBsAg assays.

Amino Acid Sequence↗
PubMedDate not supplied

Serum leptin levels in patients with nonalcoholic chronic liver disease.

BACKGROUND/AIMS: The elevated serum leptin level of patients with alcoholic cirrhosis has been reported, however, the precise mechanism is still unknown. Leptin expression and protein synthesis have also been detected in activated hepatic stellate cells in cell cultures, which play a major role in hepatic fibrosis. We evaluated the serum leptin levels of patients with nonalcoholic liver diseases including cirrhosis and chronic hepatitis. We also investigated the hepatic clearance of leptin by determining the serum leptin level in blood samples obtained from the portal and hepatic veins. METHODOLOGY: The serum leptin level of 44 patients with nonalcoholic chronic liver disease (male/female = 21/23, cirrhosis/chronic hepatitis = 30/14) and 40 control subjects (male/female = 20/20) was determined in blood samples obtained from the antecubital vein by enzyme-linked immunosorbent assay. We also assessed the relationship between the leptin level and various biochemical tests of liver function. Additionally, we determined the leptin levels in the portal and the hepatic venous blood (nonalcoholic cirrhosis = 10, nonhepatic disease = 4). RESULTS: There were positive correlations between the serum leptin level and body mass index among males and among females in the liver disease group and in the control group. However, the serum leptin level of the liver disease group and control group did not differ significantly. Among the 44 liver disease patients, only the serum cholesterol level was significantly correlated with the serum leptin level after adjusting for sex and body mass index by multiple regression analysis. Furthermore, the leptin level in hepatic venous blood was significantly lower than that in portal venous blood. However, the ratio of [leptin level in hepatic venous blood]/[leptin level in portal venous blood] in the cirrhosis group, and that in the nonhepatic disease group, did not significantly differ. CONCLUSIONS: The serum leptin level of patients with nonalcoholic liver diseases is not elevated. On the other hand, the serum leptin level of patients with alcoholic cirrhosis has been reported to be elevated. The difference in the serum leptin level of patients with nonalcoholic liver disease and that of patients with alcoholic cirrhosis may be due to a difference in factors such as the levels of cytokines or sex steroids, and/or nutrition. Furthermore, it is likely that leptin is cleared in part by the portosystemic circulation through the liver.

Adult↗
PubMedDate not supplied

Fine needle aspiration cytology of primary mediastinal germ cell tumors.

Fine needle aspiration cytology was performed on six patients with malignant mediastinal germ cell tumor: 1 pure seminoma, 1 pure embryonal carcinoma, 1 pure yolk sac tumor and 3 mixed germ cell tumors containing teratoma. Their cytologic features were compared with each other and with the cytologic features of thymoma, which arises commonly in the anterior mediastinum. A definitive cytologic diagnosis could be made only in the cases of seminoma because of its characteristic cytologic features. Cytochemical staining for germ cell alkaline phosphatase was helpful in diagnosing seminoma in the cytologic examination, while the presence of hyaline globule or alpha-fetoprotein immunostaining as the cytologic diagnostic feature of yolk sac tumor were not necessarily found in fine needle aspiration cytology. All epithelial, lymphocytic and mixed type thymomas were easily differentiated from the four types of germ cell tumor examined.

Adolescent↗
PubMedDate not supplied

Suturing techniques for a restricted operating space.

The movements of the needle holder and the needle do not correspond when the needle grip is modified for suturing in awkward sites. In this study the range of movement of the needle holder was determined for three modified grips and the optimum suturing methods were determined for horizontal and vertical suturing fields and for restricted and open operating spaces. Gripping a needle obliquely resulted in a 90 degree counterclockwise rotation of the range of movement of the needle holder. Gripping it after rotation deviated the needle holder without altering the range of movement. A combined grip achieved by rotating after shifting had an intermediate effect. The optimum suturing for a restricted horizontal operating space was to use a half-circle needle in the first half of its range of movement with the rotated grip. With the oblique grip the last half of the range should be used and in the middle the combined grip is used although gripping the needle is most stable with the oblique grip. For a restricted vertical operating space, the third quarter of the movement range was allotted to the rotated grip and the last quarter to the combined grip.

Computer Graphics↗