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Biomedical subjects

K Isono

Publications and source records attributed to K Isono.

At least 127 records · Page 7Linked to original sources
PubMed1996

Reduced messenger RNA expression level of p21 CIP1 in human colorectal carcinoma tissues and its association with p53 gene mutation.

p21 Cip1 was first isolated as one of the cyclin-dependent kinase (Cdk) interacting proteins induced by wild-type p53 gene product, and it appears to play an essential regulatory role in the control of cell proliferation as a potent, tight-binding inhibitor of cyclin-Cdk complex that blocks the G1/S transition of the cell cycle. We have now examined the p21 Cip1 mRNA expression levels in 16 surgically excised human colorectal tumor and non-tumor tissues by Northern-blot analysis with reference to the identification of p53 gene mutations. p53 gene mutations were detected in 6 tumor tissues but not in the other 10 tissues by the polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) method and following direct sequencing. The mean p21 Cip1 mRNA expression level in tumor tissues was significantly suppressed compared to that of non-tumor tissues, irrespective of p53 gene mutations. In p53 gene mutation-detected cases, the mean expression level of p21 Cip1 mRNAs of tumor tissues was about 60% of that of cases without p53 gene mutation. Moreover, the relative mRNA expression levels of p21 Cip1 significantly decreased as the pathohistological stages progressed by Dukes' staging system, while in patients with liver metastasis these levels were significantly suppressed compared to those of patients without organ metastasis. These results indicate that reduced expression of p21 Cip1 mRNA is critical for growth activity and malignant potential of human colorectal carcinoma, and that the decrease in p21 Cip1 mRNA level is due to p53 gene mutation as well as other mechanisms during human colorectal carcinogenesis.

Adult↗
PubMed1996

Detection of DCC and Ki-ras gene alterations in colorectal carcinoma tissue as prognostic markers for liver metastatic recurrence.

BACKGROUND: The mortality of patients with colorectal carcinoma depends mainly upon subsequent liver metastasis even after curative operation. However, it is very difficult to predict the incidence of liver metastasis by analyzing conventional tumor markers or pathologic findings. In the current study, the authors examined the genetic alterations of p53/DCC loci and Ki-ras in colorectal carcinoma in relation to liver metastasis, and investigated whether these gene alterations could be prognostic markers for liver metastasis. METHODS: Primary tumor tissue samples were collected at surgery from 30 patients with no liver metastasis and 24 patients with liver metastasis. Among the 30 patients with no liver metastasis at surgery, 9 developed liver metastasis after surgery. After the extraction of DNA, we investigated the loss of heterozygosity at p53/DCC loci and mutations of Ki-ras codon 12 in the colorectal carcinoma tissue from these patients. RESULTS: The incidence of allelic loss of the DCC locus was significantly greater for patients with liver metastasis that for patients who had no liver metastasis for more than 2 years (19/20:95% vs 2/5:40%, P < 0.05). However, mutations of Ki-ras codon 12 were significantly less in patients with liver metastasis than in patients with no liver metastasis for more than 2 years (6/33:18% vs 6/11:55%, P < 0.05). CONCLUSION: The current study indicated that detection of allelic loss of DCC and absence of Ki-ras codon 12 mutations are associated with the metastatic potential of colorectal carcinoma in the liver. These results suggested that these gene alterations might be reliable biologic markers for assessing the potential of liver metastasis after colorectal resection.

Adenocarcinoma↗
PubMed1996

Antitumor effect induced by the expression of granulocyte macrophage-colony stimulating factor gene in murine colon carcinoma cells.

Murine colon carcinoma cells which secrete several kinds of cytokine after retroviral transduction with corresponding genes, were examined for their antitumor effects in syngeneic mice. The mice inoculated with granulocyte macrophage-colony stimulating factor (GM-CSF) producer cells showed not only prolonged survival but also reduced tumorigenicity. The antitumor effect caused by the expression of interleukin-4 was less than that of GM-CSF, and interleukin-6 producer cells did not show any effects on the survival of the host animals. Histological examination of the GM-CSF-producing tumor revealed predominant infiltration of neutrophils and necrotic change of the tumor. The present study indicates the feasibility of cancer gene therapy with the expression of GM-CSF gene in tumor cells.

Animals↗
PubMed1996

Murine colon carcinoma cells engineered to produce human interleukin-2 induce tumor-specific anti-tumor response.

Murine colon carcinoma cells (colon 26) transduced by a retrovirus vector with the human interleukin-2 (IL-2) cDNA were studied for their tumorigenicity. Although cell growth in vitro was not affected by integration of the IL-2 gene, s.c. tumors of IL-2-producing colon 26 cells (H2) in syngeneic mice regressed spontaneously after producing small masses. Histological examination of the sites of tumor rejection revealed predominant infiltration of macrophages around the tumor necrotic mass. Subsequent challenge with parent colon 26 cells, but not with Meth A cells (fibrosarcoma of the same genetic background), did not result in tumor formation in mice which had been protected against H2 cells. Inoculation of H2 cells into syngeneic nude mice resulted in tumors with a retarded growth rate. Taken together, T cell-dependent, tumor-specific immunity is obtained by local IL-2 secretion around colon tumors, and this experimental animal model gives us a clue(s) for investigating host anti-tumor responses by cytokine production.

Animals↗
PubMed1996

Systematic mapping of autonomously replicating sequences on chromosome V of Saccharomyces cerevisiae using a novel strategy.

We have developed a new procedure for easy and rapid identification of autonomously replicating sequences (ARSs) and have applied it to the analysis of chromosome V of Saccharomyces cerevisiae. The procedure makes use of the ordered lambda phage clone bank of this chromosome that we have constructed, and includes transposition of a mini-transposon and selection of transposon-containing derivatives, isolation of their DNA and circularization at their cos-ends, transformation of yeast cells with the circularized DNA, and scoring transformation frequency. The transposon used was derived from Tn5supF, contained the yeast LEU2 gene, and was placed, together with the hyperactive transposase gene, on a mini-F plasmid for stable maintenance in Escherichia coli K-12. Sixteen regions of chromosome V showing ARS activity were identified, of which 12 were newly found in this work. Thus, the procedure will be useful for systematic genomic scale analysis of ARSs in yeast and related organisms in which ordered clone banks have been established. The average distance between adjacent ARS-containing regions was approximately 40 kb. Two-dimensional gel electrophoretic analysis of chromosome replication indicated that one of the newly identified ARSs was functional as an actual in situ replication origin, at least under the conditions employed.

Bacteriophage lambda↗
PubMed1996

Resection of the inferior head of the pancreas: report of a case.

We developed a new technique for partial resection of the head of the pancreas with an end-to-side pancreaticoduodenostomy, while preserving the duodenum, the common bile duct, and the upper part of the head of the pancreas around the duct of Santorini. A resection of the inferior head of the pancreas was performed in a patient with an intraductal mucin-producing tumor of the pancreas. This procedure is considered to be appropriate for treating both benign disease and noninvasive malignant disease involving either the uncinate process or the duct of Wirsung, because it removes both the uncinate process and the pancreatic tissue around the duct of Wirsung. We thus believe that a resection of the inferior head of the pancreas with an end-to-side pancreaticoduodenostomy can help play a significant role in the management of patients with benign diseases and localized malignant tumors of the pancreas.

Adenocarcinoma, Papillary↗
PubMed1996

Anatomic study of the bronchial arteries with special reference to their preservation during the radical dissection of the upper mediastinum lymph nodes.

BACKGROUND: The anatomy of the bronchial arteries was studied, with special reference to their preservation during the radical dissection of the upper mediastinum lymph nodes. METHODS: The bronchial arteries of 71 cadavers were studied macroscopically by use of the surgical field of right thoracotomy. The small branches difficult to identify macroscopically were described by x-ray imaging with digital subtraction angiography. Their anatomic relationship to the adjacent organs was observed microscopically. RESULTS: The bronchial arteries arising from the intercostal arteries (the intercostobronchial arteries) were observed in 66 of 71 cases. By use of the surgical field of right thoracotomy the intercostobronchial arteries were easily found and preserved. All cadavers also had other bronchial arteries arising from the aorta. These were difficult to preserve because of the depth of the surgical field and the location of their course in the dissected area. Bronchial arteries had established connection with each other via the vascular network in the tracheal proper sheath. India ink injected into the intercostobronchial arteries was observed in the tracheal proper sheath and the submucosa of the trachea. CONCLUSIONS: Saving the blood supply to the trachea is possible with careful preservation of the intercostobronchial arteries and the tracheal proper sheath during radical dissection of the upper mediastinum.

Adult↗
PubMed1996

HLA-DR antigen expression in colorectal carcinomas: influence of expression by IFN-gamma in situ and its association with tumour progression.

The authors attempted to investigate the host's immune response against colorectal carcinoma through the expression of HLA-DR antigen on carcinoma cells (Ca) on normal epithelia immediately adjacent to carcinoma (AN) in relation to tumour progression. The expression of HLA-DR antigen on Ca and on normal epithelia, both on AN and those 5-10 cm removed from the carcinoma (RN), were examined immunohistochemically. mRNAs of cytokines, IFN-gamma and TNF-alpha, were detected by reverse transcription-polymerase chain reaction (RT-PCR) in both carcinoma and remote normal tissues. The expression of HLA-DR antigen on AN was significantly increased compared with RN. Patients with tumours showing HLA-DR staining both in Ca and AN were in less advanced Dukes' stages (Dukes' A or B) compared with those without the stain. Furthermore, the expression of HLA-DR antigen in normal mucosa coincided significantly with the existence of IFN-gamma mRNA. Detection in carcinoma tissues of IFN-gamma mRNA that leads to the induction of HLA-DR antigen on AN could be an indicator of a host's immune response to carcinoma. These in vivo observations might be clinically applicable to the prediction of patients' immune responsiveness to carcinomas.

Adult↗
PubMed1996

Drug sensitivity testing for clinical samples from oesophageal cancer using adhesive tumour cell culture system.

A total of 83 specimens of surgically resected tumours from 78 patients with oesophageal cancer were assayed for drug sensitivity using an adhesive tumour cell culture system (LifeTrac CSA assay). Seventyone of 83 specimens had a sufficient number of cells to permit growth in culture and 57 of 71 (80%) were evaluable for drug response. Cells (3 x 10(3) ml-1 well-1) were cultured for 14 days and exposed to drugs on days 3-8. Growing cells were confirmed as cancer cells by immunohistochemical staining. IC90 values against several anti-cancer drugs were determined and population distributions of IC90 for each drug served as the basis for judging sensitivity. The 10th percentiles of IC90 (microgram ml-1) for CDDP, 5-FU, DOX, CPM, MTX, VP16, IFOS, VDS, BLM and CDDP + 5-FU were 0.3, 0.16, 0.005, 0.9, 0.006, 0.09, 0.8, 0.006, 0.04 and 0.15 + 0.09 respectively. The population distribution of IC90 against each drug showed a specific pattern that was very similar among histopathological gradings and stages of the disease. This system appeared to be a clinically applicable drug sensitivity test for human oesophageal cancer.

Antineoplastic Agents↗
PubMed1996

Expression of variant CD44-messenger RNA in colorectal adenocarcinomas and adenomatous polyps in humans.

BACKGROUND & AIMS: Recent studies have shown that some variant forms of CD44, a transmembrane glycoprotein expressed on various cell surfaces, might be involved in tumor progression or tumor metastasis. The aim of this study was to analyze the expression of CD44-messenger RNA (mRNA) in colorectal cancer and colorectal adenoma to further elucidate the role of CD44 in colorectal tumorigenesis. METHODS: The expression of CD44-mRNA was examined in 90 specimens from 44 patients with colorectal cancer or colorectal adenomatous polyps and in the peripheral blood leukocytes from 7 healthy volunteers by reverse transcription-polymerase chain reaction and Southern blot hybridization. RESULTS: Strong expression of the epithelial form and variant forms containing exons 11 or 12 of the CD44 gene, which conferred metastatic behavior to rat cells, was detected in primary and metastatic tumor tissues, whereas it was very weak or not detectable in normal colonic mucosae, normal liver tissue, or peripheral blood leukocytes. However, adenomatous colorectal polyps also showed as strong an expression of epithelial and variant forms of CD44 as primary and metastatic tumor tissues. CONCLUSIONS: These results suggest that variant forms of CD44-mRNA might be expressed in an early stage of colorectal carcinogenesis.

Adenocarcinoma↗
PubMed1996

Production of monoclonal antibodies against quail Pax-1.

Monoclonal antibodies (MAbs) against quail Pax-1 were generated using a fusion protein of the C-terminal part of Pax-1 and glutathione S-transferase. The MAbs generated could detect quail Pax-1 protein by Western blotting and immunoprecipitate it from whole cell extracts of quail embryos, indicating their usefulness for biochemical analyses of Pax-1 protein function in development or oncogenesis.

Animals↗
PubMed1996

p53-Dependent and -independent transactivation by the E6 protein of human papillomavirus type 16.

The mechanism by which the E6 protein of human papillomavirus type 16 (HPV-16) transactivates heterologous virus promoters has not been established. In this study, the involvement of p53-mediated transcriptional repression in transactivation by the HPV-16 E6 protein was examined using several virus promoters. HPV-16 E6 transactivated the TATA box-containing simian virus 40 early promoter and the Rous sarcoma virus long terminal repeat in p53-containing cells but not in p53-deficient cells. In contrast, the adenovirus E2 promoter was transactivated both in p53-containing and p53-deficient cells. These results indicate that the transactivation activity of the HPV-16 E6 protein is mediated by p53-dependent and promoter-specific p53-independent pathways.

Adenovirus E2 Proteins↗
PubMed1996

Structure-activity relationship within a series of degradation products of tautomycin.

Tautomycin, a protein serine/threonine phosphatase inhibitor, was chemically degraded, and five derivatives were investigated for their biological activities. None of them exerted any inhibitory effects on the activity of protein phosphatase types 1 and 2A. However, one derivative, named TM2a, induced a significant morphological change (bleb-formation) of human myeloid leukemia K562 cells. TM2b, the trimethyl ester of TM2, did not induce bleb-formation. Thus, the maleic anhydride structure played an important role in the biological activity. The biological properties of TM2a toward K562 cells resembled those of a phorbol ester, rather than of tautomycin. The phorbol ester-induced bleb formation was abrogated by a non-specific inhibitor of protein kinases, staurosporine, and by an inhibitor of protein kinase C (PKC), H-7, but TM2a-induced bleb formation was abrogated only by staurosporine. Enhanced phosphorylation of the two proteins was observed after their exposure to TM2a. This suggest that the effect was not due to any inhibition of protein phosphatase 1 or 2A, but rather to the activation of an unidentified kinase, possibly of the PKC family, or to inhibition of a protein phosphatase other than type 1 or 2A.

Antifungal Agents↗