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Biomedical subjects

I Tamura

Publications and source records attributed to I Tamura.

At least 19 recordsLinked to original sources
PubMed2001

Combination effect of adenovirus-mediated pro-apoptotic bax gene transfer with cisplatin or paclitaxel treatment in ovarian cancer cell lines.

To develop a novel therapeutic strategy for ovarian cancer, we constructed a recombinant adenovirus which highly expresses pro-apoptotic Bax protein and examined its therapeutic effect on a series of ovarian cancer cell lines: A2780, A2780/cDDP, OVCAR-3 and SK-OV-3. A recombinant adenovirus carrying the Bax-alpha gene (AxCALNKYbax) induced high expression of the Bax-alpha protein in all the cell lines. The cytotoxic effect of Bax was observed in three ovarian cancer cell lines: the per cent reduction in the number of cells was 40.0% for cisplatin-sensitive A2780, 50.0% for cisplatin-resistant A2780/cDDP, and 64.8% for marginally cisplatin-resistant OVCAR-3. In contrast, it was only 12.3% for cisplatin-resistant SK-OV-3. Cisplatin-resistant A2780/cDDP had a p53 mutation and exhibited attenuated Bax induction after cisplatin treatment, which may explain why supplementation of Bax was effective in this chemoresistant ovarian cancer. Combination with cisplatin or paclitaxel enhanced the cytotoxic effect of Bax induction in all but one cell line including cisplatin-resistant A2780/cDDP. It appears that adenovirus-mediated Bax induction, with or without combination with conventional chemotherapy, useful strategy for the treatment of ovarian cancer.

Adenoviridae↗
PubMed2001

Regulation of Cyr61 gene expression by mechanical stretch through multiple signaling pathways.

The cysteine-rich protein 61 (Cyr61) is a signaling molecule with functions in cell migration, adhesion, and proliferation. This protein is encoded by an immediate early gene whose expression is mainly induced by serum growth factors. Here we show that Cyr61 mRNA levels increase sharply in response to cyclic mechanical stretch applied to cultured bladder smooth muscle cells. Stretch-induced changes of Cyr61 transcripts were transient and accompanied by an increase of the encoded protein that localized mainly to the cytoplasm and nucleus of the cells. With the use of pharmacological agents that interfere with known signaling pathways, we show that transduction mechanisms involving protein kinase C and phosphatidylinositol 3-kinase activation partly blocked stretch-induced Cyr61 gene expression. Selective inhibition of Rho kinase pathways altered this stretch effect as well. Meanwhile, using inhibitors of the actin cytoskeleton, we show that Cyr61 gene expression is sensitive to mechanisms that sense actin dynamics. These results establish the regulation of Cyr61 gene by mechanical stretch and provide clues to the key signaling molecules involved in this process.

Animals↗
PubMed2001

Laparoscopic surgery using a newly designed suction lifter.

The authors describe a simple and available abdominal wall-lift technique for endoscopic surgery that involves a new suction lifter that they designed for laparoscopic surgery. Since July 1998, the authors have used this technique successfully in eight patients with appendicitis, in one patient with a perforated duodenal ulcer, and in one patient with an adenoma of the ascending colon.

Adenoma↗
PubMed1999

Correlation of E-cadherin and alpha-catenin expression with differentiation of oral squamous cell carcinoma.

The precise mechanism of disruption of cell-cell adhesion in oral squamous cell carcinomas has yet to be established. We therefore sought to clearly this mechanism by investigating expression of both E-cadherin (E-CD) and alpha-catenin (alpha-CAT), which is an intracellular CD-binding molecule, in squamous cell carcinomas of the tongue, gingiva and floor of the mouth using immunohistochemical and immunoblotting techniques. We found that reduced expression of both E-CD and alpha-CAT occurred more frequently in moderately- and poorly-differentiated carcinomas than in well-differentiated specimens (p < 0.001), and this reduced expression showed no regional specificity. Relatively frequent loss of alpha-CAT expression in poorly-differentiated carcinomas was detected by both immunohistochemical and immunoblotting analyses. These findings suggest that E-CD and alpha-CAT are both important regulators of intercellular adhesion, and that the reduction of these molecules is also linked to the process of tumor dedifferentiation.

Antibodies, Monoclonal↗
PubMed1998

Segmental mediolytic arteritis [correction of arteries]: a case report with review of the literature.

Segmental mediolytic arteritis is a very rare vascular disease which causes sudden intraabdominal hemorrhage. The disease is characterized by degeneration of the arterial media, followed by aneurysmal dilatation and rupture of the involved artery. Up to now, only 13 cases have been reported, and this unique disease is not fully recognized among general pathologists and physicians. Here, we present a case of segmental mediolytic arteritis involving the propria hepatic artery, which resulted in intraabdominal hemorrhage, and consequently hypovolemic circulatory disturbance. Histologically, the rupture focus showed degeneration and desquamation of the intima and media with fibrin-like material covering the exposed adventitia. Inflammatory infiltrates were only noted in the rupture focus as a secondary reactive change. Other than the rupture focus, there were two foci showing similar findings. This disease has rarely been reported and is seldom recognized as a cause of arterial rupture. In cases of sudden intraabdominal hemorrhage, segmental mediolytic arteritis should be considered as a possible cause in addition to atherosclerotic and mycotic aneurysm, traumatic injury and vasculitis syndromes.

Adult↗
PubMed1998

Long-term follow-up of a patient with hepatocellular carcinoma associated with triple hepatitis virus (HBV, HDV, HCV) infection.

A 69-year-old Japanese man with hepatocellular carcinoma (HCC) associated with triple hepatitis viruses [hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis D virus (HDV)] infection is reported. The patient had a past history of intravenous drug abuse and a tattoo on his back. A liver biopsy, performed in November 1989, showed HCC associated with cirrhosis. HBsAg and anti-HD antibody had been detected repeatedly starting in August 1984 and anti-HCV antibody was detected in 1990. By indirect immunoperoxidase staining the HD antigen was detected in the nuclei of hepatocytes of biopsy specimens and noncancerous liver cells obtained from autopsy specimens. Liver cirrhosis associated with triple hepatitis virus infection developed to hepatocellular carcinoma, and transcatheter arterial embolization treatment for HCC was effective. Despite having HCC and cirrhosis, the patient lived well beyond the expected time.

Aged↗
PubMed1997

Age-related changes in collagen, laminin and tenascin in the infant rat submandibular gland.

We investigated biochemically and immunohistochemically the age-related changes in collagen (types I, III and IV), laminin and tenascin of the extracellular matrix in the submandibular gland of infant rats. The hydroxyproline content markedly increased on day 14 after birth. Electrophoretic profile revealed alpha chains of only type I collagen up to day six after birth. Type III collagen, which was diffusely distributed in interlobular connective tissue, was gradually expressed from day seven after birth. Type IV collagen content increased from day seven. Laminin content gradually increased with age. Tenascin immunohistochemically showed weak expression only around the vessel walls up to day seven. In addition, this expression markedly increased around acinar and ductal walls as basement membrane components on day 14 after birth. These findings suggest that rat submandibular gland types I and IV collagen, and laminin are already present during the fetal stage and relate to construction of tissue, and that type III collagen and tenascin, which increased from day seven after birth, relate to maturation.

Aging↗
PubMed1996

Characteristics and localization of rat submandibular gland proteoglycans.

The submandibular gland proteoglycans were investigated biochemically and immunohistochemically in male Sprague-Dawley rats. Proteoglycans were extracted with 4 M guanidine-HCl, followed by ultracentrifugation in a CsCl density gradient, and fractionated by ion-exchange chromatography and gel filtration. The molecular weight of PGs was estimated by SDS-PAGE and immunoblot analysis with monoclonal antibodies (HepSS-1 or 6-B-6). The glycosaminoglycan side-chains in the proteoglycan fractions were identified by electrophoresis on cellulose acetate membrane. Three proteoglycan fractions were obtained. One was a heparan sulphate proteoglycan that migrated as a diffuse band of about 210 kDa. The other two fractions contained at least two dermatan sulphate proteoglycans of 70-85 kDa and 40-50 kDa. Digestion of these two proteoglycans with chondroitinase ABC, but not heparitinase, produced two bands of 50 and 21 kDa, which were core proteins. The smaller dermatan sulphate proteoglycan may be a portion of the other, as the core protein of both bound to 6-B-6 antibody, and sugar chains of both were the same (20-30 kDa). Heparan sulphates recognized by antibody HepSS-1 were observed widely in the basement membrane, fibrous connective tissue, and striated and excretory ductal cells, while dermatan sulphate proteoglycans recognized by antibody 6-B-6 were located in the connective tissue surrounding striated and excretory ducts.

Animals↗
PubMed1995

Functional localization of bilateral auditory cortices using an MRI-linked whole head magnetoencephalography (MEG) system.

In 20 healthy subjects, auditory evoked magnetic fields were measured over the entire head, using a helmet-shaped 66-channel MEG system linked to MRI. When the left or right ear was stimulated by 60 msec 2 kHz tones, the prominent 100 msec response (N100m) appeared significantly earlier in the contralateral hemisphere than in the ipsilateral one. In 16 cases, the N100m dipolar field patterns were clear in both hemispheres, overlapping each other across the midline. The N100m sources were estimated using a 2-dipole model in a spherical conducting medium with the size and location of the sphere determined individually according to the MRI images. No differences were found between the contralateral and ipsilateral N100m dipole positions in one hemisphere. When superimposed on MRI, the N100m dipoles were located precisely on the upper surface of bilateral temporal lobes with a standard deviation of 2.2 mm in the superior-inferior direction. In 16 right handed males, the right hemispheric N100m dipoles were 6 mm anterior to the left hemispheric dipoles. The whole head MEG is suitable to see small but significant differences of bilateral cerebral function, with exceptionally high spatial resolution, confirmed by the MRI-linked system.

Adult↗
PubMed1995

Acylated anthocyanins from fruits of Sambucus canadensis.

Two new acylated anthocyanin glycosides were isolated from fruits of Sambucus canadensis. The structures were determined to be cyanidin 3-O-(6-O-Z-p-coumaroyl-2-O-beta-D-xylopyranosyl)- beta-D-glucopyranoside)-5-O-beta-D-glucopyranoside and cyanidin 3-O-(6-O-E-p-coumaroyl-2-O-beta-D-xylopyranosyl)-beta-D- glucopyranoside.

Acylation↗
PubMed1994

Hepatitis C virus genotypes, reactivity to recombinant immunoblot assay 2 antigens and liver disease.

To clarify the relationship between hepatitis C virus (HCV) genotypes and liver disease, we typed HCV genomes in the sera of 151 blood donors, 180 patients with type C chronic liver disease (CLD), and 30 haemophiliacs residing in Hiroshima, Japan. All of the subjects were positive for anti-HCV and HCV-RNA, and were examined for seroreactivity to HCV-specific antigens. The HCV genotypes were determined by polymerase chain reaction (PCR) with type-specific primers deduced from the putative core region of the HCV genome. Significantly more (P < 0.001) type III HCV was found in the samples from the CLD patients (80%) than in those from the blood donors (55%). Significantly more (P < 0.001) type III HCV was found in the samples from the blood donors (29.1%) than in those from the CLD patients (11.7%). There was no significant difference in the distribution of the HCV types among the patients with chronic active hepatitis, liver cirrhosis, and hepatocellular carcinoma. A four-antigen recombinant immunoblot assay (RIBA-2) assay was used to compare the serum samples for their reactivity to a range of structural and nonstructural peptides specific for HCV (5-1-1, C100-3, C33c, and C22-3). The frequency of seropositivity to 5-1-1 and C100-3 was significantly higher (P < 0.001) in type II HCV-infected blood donors than in type III HCV-infected donors (68.2% and 65.9% vs. 4.5% and 22.7%, respectively). Among the type III HCV-infected individuals, the CLD patients had a significantly higher (P < 0.01) frequency of seropositivity to 5-1-1 than the blood donors (33.3% vs. 4.5%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Inhibition of flagellar motility of fowl spermatozoa by L-carnitine: its relationship with respiration and phosphorylation of axonemal proteins.

The action of carnitine in regulating fowl sperm motility was investigated. As the concentration of L-carnitine was increased (0-20 mM), the motility of intact and demembranated fowl spermatozoa was reduced at 30 degrees C. Even the presence of 1 mM CaCl2 before the addition of 10 mM carnitine could not prevent the inhibition of motility at 30 degrees C and 40 degrees C. However, motility was restored by reducing the concentrations of carnitine. Carnitine also inhibited the oxygen consumption and ATP concentrations of intact spermatozoa, and caused a reduction in intracellular free Ca2+ concentrations. Phosphorylation of a 50 kDa protein and dephosphorylation of 24 kDa and 30 kDa proteins of demembranated spermatozoa were observed after the addition of carnitine. In contrast, the flagellar ATPase activity of crude dynein extract was not affected by the addition of carnitine. These results suggest that inhibitory effect of carnitine for motility may be directly on the axonemal phosphoproteins, but not directly on the dynein ATPase activity. The physiological role of carnitine for fowl spermatozoa in the ductus deferens is discussed.

Adenosine Triphosphate↗
PubMed1994

[Diagnosis of hepatocellular carcinoma using chicken anti-monoclonal antibody--as tumor marker on the heterophilic hanganutziu-deicher antigen].

The Hanganutziu-Deicher (HD) antigen is a heterophilic antigen with N-glycolylneuraminic acid as the terminal carbohydrate, and has attracted much attention as one of tumor-associated antigens. This antigen is absent from normal tissues of human and chicken but expressed in human neoplasms. Extensive research on HD antigen has not be made yet to show the intimate correlation with human neoplasm, but it is attracting an attention as a diagnostic marker for the definition of cancer. We made two different chicken monoclonal antibodies against HD antigen as a pathological tool for hepatocellular carcinoma (HCC). The hybrid cell, which produced antibodies, were prepared by means of fusion technology with HD3 antigen-immunized chicken spleen cells and HAT-sensitive chicken B cell line termed R27H4. The two antibodies had a different characteristic, one recognized only glycolipid, and the other recognized glycoprotein as well as glycolipid. Glycolipid type HD antigen and glycoprotein type HD antigen were identified by using two chicken anti-HD monoclonal antibodies. Glycolipid type HD antigen was detected by flow cytometry in 4 out of 24 HCC samples (87.5%). In our study, increased serum levels of IgG type and/or IgM type HD antibodies were observed in 21 out of 24 patients with HCC (87.5%). The presence of these antibodies is attributable to the expression of the HD antigen in cells of HCC. Eleven out of 24 patients with HCC were negative for AFP and PIVKA-II, and 10 out of these 11 patients (90.9%) were positive for anti-HD antibodies. We consider that patients with HCC should be screened for HD antigen and antibody for an early diagnosis of hepatocellular carcinoma; the same as for AFP and PIVKA-II both of which are tumor-associated antigens that have been associated with for hepatocellular carcinoma.

Animals↗
PubMed1994

Establishment and characterization of a human tongue cancer xenograft line in nude mice.

We established a human tongue cancer (well-differentiated squamous cell carcinoma) xenograft line, LK-1, in nude mice. LK-1 showed logarithmic growth from 5 to 7 weeks after transplantation, and the take rate for 25 generations was 95.0%. We confirmed the expression of cytokeratins 1, 5, 7, 10, 14, 16, 17, 18 and 19, and type I, III, IV and V collagens by electrophoretical and immunohistochemical analyses. Although the amount of type I, IV and V collagens increased gradually from 5 weeks after transplantation, the distribution of type IV collagen was often discontinuous in the cancer basement membrane. From these data we concluded that LK-1 is an excellent model for the investigation of the cell biology of well-differentiated oral squamous cell carcinoma, and for examining the effects of clinical therapies for this disease.

Adult↗
PubMed1993

Waldenström's macroglobulinemia associated with amyloidosis and membranous nephropathy.

A 61-year-old man with massive proteinuria and hyper gamma-globulinemia was admitted to hospital because of massive edema and pulmonary infection. He showed significantly high level of serum IgM (3244 mg/dl) with lambda-type M-protein and Bence Jones protein detected by immunoelectrophoresis. Renal biopsy specimen showed not only the diffuse amorphous amyloid deposition in mesangial area but global thickening of capillary wall with spike formation by silver staining which was similar to the spicular formation. Immunofluorescence disclosed find granular deposition of IgG and C3 along the capillary wall and the electromicroscopic findings clearly showed both massive amyloid fibril at mesangial area and diffuse epimembranous electron dense deposits. lambda-type Bence Jones protein in macroglobulinemia was suggested not only the cause of renal amyloidosis but also the antigenic origin of membranous nephropathy in this case.

Amyloidosis↗