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Biomedical subjects

Michio Ogawa

Publications and source records attributed to Michio Ogawa.

At least 37 records · Page 2Linked to original sources
PubMed2004

Protective effect of exogenous adenosine triphosphate on hypothermically preserved rat liver.

AIM: To clarify the protective effect of exogenous adenosine triphosphate (ATP) on hypothermically preserved rat livers. METHODS: Establishment of continuous hypothermic machine perfusion model, detection of nucleotides in hepatocytes with HPLC, measurement of activities of LDH and AST in the perfusate, observation of histopathological changes in different experiment groups, and autoradiography were carried out to reveal the underlying mechanism of the protective effect of ATP. RESULTS: The intracellular levels of ATP and EC decreased rapidly after hypothermic preservation in control group, while a higher ATP and EC level, and a slower decreasing rate were observed when ATP-MgCl(2) was added to the perfusate (P<0.01). As compared with the control group, the activities of LDH and AST in the ATP-MgCl(2) group were lower (P<0.05). Furthermore, more severe hepatocyte damage and neutrophil infiltration were observed in the control group. Radioactive [alpha-(32)P] ATP entered the hypothermically preserved rat hepatocytes. CONCLUSION: Exogenous ATP has a protective effect on rat livers during hypothermical preservation. However, Mg(2+) is indispensable, addition of ATP alone produces no protective effect. The underlying mechanism may be that exogenous ATP enters the hypothermically preserved rat liver cells.

Adenosine Triphosphate↗
PubMed2004

Steatotic liver allografts up-regulate UCP-2 expression and suffer necrosis in rats.

BACKGROUND: Fatty split-liver and living-related liver transplantation is associated with massive hepatocellular necrosis during acute rejection. Uncoupling protein (UCP)-2 is a potential regulator of energy expenditure and ATP production. We investigated the role of UCP-2 and the effects of a metalloprotease inhibitor, Y-39083, on hepatocellular injury in fatty liver allografts in rats. MATERIALS AND METHODS: Rats were treated for 6 weeks with high-ethanol or isocalic dextrose-containing liquid diets that caused characteristic pericentral lipid accumulation. Alcoholic or nonalcoholic fatty livers from ACI (RT1a) rats were transplanted into LEW (RT1l) rats orthotopically. Hepatic necrosis was determined histologically following liver transplantation. UCP-2 mRNA levels in the hepatic allograft and in primary cultured hepatocytes from fatty liver stimulated by tumor necrosis factor (TNF)-alpha were determined. Y-39083 was administered to recipient rats continuously at 5 mg/kg/day using an osmotic infusion mini-pump. RESULTS: The acute rejection index on day 5 posttransplant in alcoholic and nonalcoholic fatty donor livers was higher than in lean grafts. Massive hepatocyte necrosis was more prominent in alcoholic than nonalcoholic fatty liver allografts and was not seen in lean allografts. UCP-2 transcripts in both alcoholic and nonalcoholic fatty liver allografts were higher than in lean allografts. Serum TNF-alpha concentrations in recipient rats with either fatty liver allograft were greater than in animals with lean allografts. In vitro UCP-2 mRNA levels in primary cultured hepatocytes from both alcoholic and nonalcoholic fatty livers increased more after stimulation with TNF-alpha than those from lean livers. In vitro TNF-alpha production by Kupffer cells isolated from alcohol-induced fatty liver allografts on day 3 posttransplant was greater than those from lean allografts. Y-39083 significantly reduced serum concentrations of TNF-alpha and prevented massive hepatocellular necrosis in rats with both alcoholic and nonalcoholic fatty liver allografts. CONCLUSION: Liver grafts with steatosis up-regulated UCP-2. TNF-alpha further enhanced UCP-2 transcripts, inducing massive hepatocellular necrosis during acute rejection. Posttransplantation necrosis may be prevented by metalloprotease inhibitors.

Animals↗
PubMed2004

Relationship between neutrophil elastase and acute lung injury in humans.

We conducted clinical trials in patients with acute lung injury (ALI) associated with systemic inflammatory response syndrome using a selective neutrophil elastase inhibitor, sivelestat sodium hydrate (Sivelestat), to investigate the involvement of neutrophil elastase in ALI. In the phase III double-blind study (Study 1) in 230 patients, the efficacy of Sivelestat was evaluated with the pulmonary function improvement (PFI) rating as the primary endpoint, and the weaning rate from mechanical ventilator, the discharge rate from intensive care unit (ICU), and the survival rate as secondary endpoints. Afterwards, an unblinded study (Study 2) in 20 patients was conducted using procedures for weaning from mechanical ventilation to reevaluate its efficacy with ventilator-free days (VFD) value, the primary endpoint, and to compare with that of Study 1 subgroup, which met the selection criteria used in Study 2. Sivelestat increased PFI rating, reduced duration of mechanical ventilation, and shortened stay in ICU in Study 1, although there was no significant efficacy on the survival rate. VFD value in Study 2 was comparable to that in the optimal-dose group of Study 1 subgroup, and increase in VFD value correlated with PFI rating and increase in ICU free days. It was concluded that neutrophil elastase may be involved in the pathogenesis of ALI in humans.

Adolescent↗
PubMed2004

Involvement of the mitogen-activated protein kinase kinase 2 in the induction of cell dissociation in pancreatic cancer.

In our previous investigation, mitogen-activated protein kinase kinase 2 (MEK2) was detected as a factor which was correlated to the potential of invasion-metastasis. In this study, the immunocytochemical, immunohistochemical and mRNA expressions of MEK2 were examined in pancreatic cancer cell lines and tissue samples, respectively. Constitutive expressions of MEK2 and phosphorylated MEK (p-MEK) were observed in PC-1.0 and ASPC-1 cells, which exhibited a growth pattern of single cells, whereas the relevant expressions were quite faint in PC-1 cells and CAPAN-2 cells, which exhibited a growth pattern of island-like clonies. Simultaneous inductions of MEK2 expressions and cell dissociation were observed after the treatment with a conditioned medium (CM) of PC-1.0 cells. The expression of MEK2 and p-MEK were reduced and the cell aggregation was found in PC-1.0 and ASPC-1 cells after U0126 (a MEK inhibitor) treatment. In vivo, both the MEK2 and p-MEK overexpressed in human pancreatic cancer tissues and p-MEK was found to be more strongly expressed in the invasive front than that in the center of tumor (P<0.05). MEK2 is closely related to pancreatic cancer cell dissociation. MEK2 activation is probably involved in the first step of the cascade in the invasion-metastasis of pancreatic cancer.

Adult↗
PubMed2004

Relationship between the expression of extracellular signal-regulated kinase 1/2 and the dissociation of pancreatic cancer cells: Involvement of ERK1/2 in the dissociation status of cancer cells.

Mitogen-activated protein kinase kinase 2 (MEK2), the upstream kinase of extracellular signal-regulated kinase 1/2 (ERK1/2) was previously isolated as cancer cell dissociation related factor. In this study, to further clarify the regulatory mechanism of cancer cell dissociation, two hamster (PC-1.0 and PC-1) and human (Capan-2 and AsPC-1) pancreatic cancer cell lines were analyzed immunocytochemically with anti-ERK1, anti-ERK2 and anti-phosphorylated ERK1/2 (p-ERK1/2) antibodies. U0126 (a MEK1/2 inhibitor) significantly suppressed ERK2 and p-ERK1/2 expressions in PC-1.0 and AsPC-1 cells (P<0.05). Cancer cell dissociation factor (DF) markedly induced ERK2 and p-ERK1/2 expressions in PC-1 and Capan-2 cells (P<0.05), and the induced ERK2 and p-ERK1/2 expressions were inhibited by subsequent U0126-treatment (P<0.05). Simultaneously, light microscopic images showed that DF clearly induced cell dissociation in PC-1 and Capan-2 cells, while U0126-treatment induced cell aggregation in these pancreatic cancer cells. ERK2 activation is closely involved in cell dissociation of pancreatic cancer cells.

Animals↗
PubMed2004

Analysis of invasion-metastasis mechanism in pancreatic cancer: involvement of tight junction transmembrane protein occludin and MEK/ERK signal transduction pathway in cancer cell dissociation.

Mitogen-activated protein kinase kinase 2 (MEK2) was detected as an invasion-metastasis related factor between highly invasive (PC-1.0) and weakly invasive (PC-1) pancreatic cancer cell lines in our previous study. On the other hand, tight junction (TJ) was found to be correlated with carcino-genesis and tumor development. In this study, the expressions and correlation of TJ transmembrane protein occludin and MEK/extracellular signal-regulated kinase (ERK) signaling pathway were analyzed to clarify the regulatory mechanism of cell dissociation in pancreatic cancer cells. Two hamster (PC-1.0 and PC-1) and human (AsPC-1 and CAPAN-2) pancreatic cancer cell lines were analyzed immunocytochemically with anti-occludin, phosphorylated MEK1/2 (p-MEK1/2), phosphorylated ERK1/2 (p-ERK1/2) antibodies. MEK1/2 inhibitor U0126 significantly induced the expression of occludin at the cell-cell junction and substantially suppressed the p-MEK1/2 and p-ERK1/2 expressions in PC-1.0 and AsPC-1 cells. In contrast, dissociation factor (DF) treatment obviously disrupted the occludin expressions at the sites of cell-cell junction and markedly induced the p-MEK1/2 and p-ERK1/2 expressions in PC-1 and CAPAN-2 cells. In addition, occludin expressions at cell-cell junction were restored and p-MEK1/2 and p-ERK1/2 expressions were suppressed by subsequent U0126-treatment in DF treated PC-1 and CAPAN-2 cells. Correspondingly, light microscopic images showed that DF induced the dissociation of cell island-like colonies in PC-1 and CAPAN-2 cells, and U0126-treatment induced cell aggregation in these pancreatic cancer cells. Occludin is involved in the cell dissociation in pancreatic cancer cells. Moreover, MEK/ERK signaling pathway probably regulates the cell dissociation status of pancreatic cancer through influencing the intracellular localization and expression of occludin.

Animals↗
PubMed2004

Relationship between activation of epidermal growth factor receptor and cell dissociation in pancreatic cancer.

In our previous investigations, mitogen-activated protein kinase kinase 2 (MEK2)/extracellular signal-regulated kinase 2 (ERK2) signaling pathway was found to be correlated with the cell dissociation induced by dissociation factor (DF) in pancreatic cancer cells. In this study, the expressions of epidermal growth factor receptor (EGFR), phosphorylated EGFR (p-EGFR), and its downstream kinases MEK1/2 and ERK1/2, were analyzed to clarify the regulatory mechanism of cell dissociation in pancreatic cancer cells. Two hamster (PC-1.0 and PC-1) and two human (AsPC-1 and Capan-2) pancreatic cancer cell lines were used. Immunocytochemical study was performed using anti-EGFR, p-EGFR, phosphorylated MEK1/2 (p-MEK1/2), and phosphorylated ERK1/2 (p-ERK1/2) antibodies. DF-treatment markedly induced the expressions of EGFR, p-EGFR, p-MEK1/2, p-ERK1/2, as well as the dissociation of cell colonies in PC-1 and Capan-2 cells. In contrast, AG1478 (an EGFR inhibitor) treatment significantly induced the cell aggregation in PC-1.0 and AsPC-1 cells which usually grew as single cells, but strongly suppressed the expressions of EGFR, p-EGFR, p-MEK1/2, and p-ERK1/2. These observations demonstrate that activation of EGFR is closely involved in cell dissociation in pancreatic cancer through activating MEK/ERK signaling pathway.

Adenocarcinoma↗
PubMed2004

Arrangement of expression and distribution of tight junction protein claudin-1 in cell dissociation of pancreatic cancer cells.

Mitogen-activated protein kinase kinase 2 (MEK2) was isolated previously as a potential factor related to cancer cell dissociation in highly (PC-1.0) and weakly (PC-1) invasive pancreatic cancer cells. On the other hand, changes of structure and function of tight junction (TJ) are reported to be correlated with carcinogenesis and tumor development. In this study, immunocytochemistry and Western blot analysis were performed in pancreatic cancer cells using anti-claudin-1, MEK2 and phosphorylated MEK1/2 (p-MEK1/2) antibodies to reveal the correlation between TJ and cancer cell dissociation, as well as the involvement of MEK2 in regulation of TJ in cell dissociation of pancreatic cancer. After incubation with conditioned medium of PC-1.0 cells, plasma membrane distribution of claudin-1 was obviously disrupted, and expressions of MEK2 and p-MEK1/2, as well as dissociation of cell colonies, were significantly induced in PC-1 and CAPAN-2 cells. However, U0126 (a MEK1/2 inhibitor) treatment apparently induced the plasma membrane distribution of claudin-1 and aggregation of single cells in PC-1.0 and AsPC-1 cells, synchronously seriously suppressed MEK2 and p-MEK1/2 expression. Arrangement of expression and distribution of claudin-1 is closely related to cell dissociation status in pancreatic cancer cells through MEK2 activation.

Blotting, Western↗
PubMed2004

[Concept of SIRS and severe acute pancreatitis].

Acute pancreatitis is a potentially fatal disease, the severity of which ranges from a mild edematous form to a severe necrotizing form. Most patients develop systemic inflammatory response syndrome (SIRS), which is induced by proinflammatory cytokines. The cytokine production can be induced by activation of Toll-like receptor. The breakdown products of the pancreatic and peripancreatic tissues by proteases might be the agonists. Cytokines are supposed to be produced as a biological defense system. However, cytokines may often evoke organ failure and/or immunosuppressive state, if they would be produced excessively. To express this complicated pathologic condition, Ogawa proposed a concept of LISIS(local inflammation-induced systemic immunosuppression syndrome). We have to pay attention to such aspects in the management of this disease.

Acute Disease↗
PubMed2004

[Successful treatment of liver metastasis and extrahepatic metastasis with hepatic arterial infusion of CDDP, CPT-11, and 5-FU].

A 63-year-old man, who had been operated with right hemicolectomy 1 year and 3 months ago, had giant liver metastasis, lung metastasis, and local dissemination tumor due to ascending colon cancer. He was treated by systemic chemotherapy with 5-FU and the treatment evaluation was PD on CT. After admission to our hospital, he was treated by hepatic arterial infusion chemotherapy with CDDP, CPT-11, and 5-FU. After 3 courses of the treatment, each recurrent lesion decreased on CT and the CEA level decreased. There were no side effects except mild diarrhea. We believe hepatic arterial infusion chemotherapy with CDDP, CPT-11, and 5-FU may be an effective strategy against liver metastasis and extrahepatic metastsis due to colon cancer.

Antimetabolites, Antineoplastic↗
PubMed2003

Activation of m-calpain is required for chromosome alignment on the metaphase plate during mitosis.

Calpains form a superfamily of Ca(2+)-dependent intracellular cysteine proteases with various isoforms. Two isoforms, micro- and m-calpains, are ubiquitously expressed and known as conventional calpains. It has been previously shown that the mammalian calpains are activated during mitosis by transient increases in cytosolic Ca(2+) concentration. However, it is still unknown whether the activation of calpains contributes to particular events in mitosis. With the use of RNA interference (RNAi), we investigated the roles of calpains in mitosis. Cells reduced the levels of m-calpain, but not mu-calpain, arrested at prometaphase and failed to align their chromosomes at the spindle equator. Specific peptidyl calpain inhibitors also induced aberrant mitosis with chromosome misalignment. Although both m-calpain RNAi and calpain inhibitors affected neither the separation of centrosomes nor the assembly of bipolar spindles, Mad2 was detected on the kinetochores of the misaligned chromosomes, indicating that the prometaphase arrest induced by calpain inhibition is due to activation of the spindle assembly checkpoint. Furthermore, when calpain activity was inhibited in cells having monopolar spindles, chromosomes were clustered adjacent to the centrosome, suggesting that calpain activity is involved in a polar ejection force for metaphase alignment of chromosomes. Based on these findings, we propose that activation of m-calpain during mitosis is required for cells to establish the chromosome alignment by regulating some molecules that generate polar ejection force.

Calcium↗
PubMed2003

Glypican-3, overexpressed specifically in human hepatocellular carcinoma, is a novel tumor marker.

With the global pandemic of hepatitis B and C infections, the incidence of Hepatocellular carcinoma (HCC) is rapidly increasing world wide. We identified glypican-3 (GPC3), a novel oncofetal gene over-expressed specifically in human HCC, as based on data of cDNA microarrays. As GPC3 is a GPI-anchored membrane protein and could be secreted, we attempted to detect secreted GPC3 protein in sera from HCC patients using Western blotting and ELISA. GPC3 protein was positive in sera of 40.0% (16/40) of HCC patients, and negative in sera from subjects with liver cirrhosis (LC) (0/13), chronic hepatitis (CH) (0/34), and healthy donors (0/60). All subjects were Japanese. Although 12 of 40 HCC patients were negative for both alpha-fetoprotein (AFP) and PIVKA-II well known tumor markers of HCC, four of these were GPC3-positive in the sera. We also observed vanishing GPC3 protein in the sera of three patients after the surgical treatment for HCC. On the other hand, immunohistochemical analysis revealed that HCC expressed GPC3 protein in all 14 HCC patients tested. In conclusion, GPC3, as defined in this study was shown to be a useful tumor marker for cancer-diagnosis for large numbers of patients with HCC.

Adult↗
PubMed2003

Mutational analysis of the pancreatic secretory trypsin inhibitor gene in familial and juvenile pancreatitis in Japan.

BACKGROUND: Mutations in the pancreatic secretory trypsin inhibitor ( PSTI) gene have been reported in patients suffering from chronic pancreatitis. The aim of the present study was to investigate whether similar gene mutations are present in familial and juvenile pancreatitis patients in Japan. METHODS: All four exons of the PSTI gene and their flanking intronic sequences were amplified by polymerase chain reaction and sequenced for 37 familial pancreatitis patients (24 families) and 15 juvenile pancreatitis patients, distributed throughout Japan. RESULTS: Three types of exonic mutation in the PSTI gene were observed. The N34S mutation was found in six familial pancreatitis patients (three families) and in one juvenile pancreatitis patient, and the R67C mutation was found in one familial pancreatitis patient and one juvenile pancreatitis patient. We also found a 272C>T mutation in the 3' untranslated region of exon 4 in one familial pancreatitis patient and four juvenile pancreatitis patients. It should be noted that the N34S mutation was cosegregated with two intronic mutations, specifically, IVS1-37T>C and IVS3-69insTTTT. CONCLUSIONS: The same set of N34S mutations (N34S + IVS1-37T>C + IVS3-69insTTTT) that exists in other countries was found in the PSTI gene in Japanese familial and juvenile pancreatitis patients. Another unique mutation (R67C) was also observed in two patients; 272C>T was suggested to be a normal polymorphism.

Adolescent↗
PubMed2003

Modulation of tumor-selective vascular blood flow and extravasation by the stable prostaglandin 12 analogue beraprost sodium.

Improved delivery of macromolecular drugs to solid tumor is known as the enhanced permeability and retention (EPR) effect of macromolecular drugs and lipids. We report here that a prostaglandin I2 (PGI2) analogue induces enhancement of tumor-selective drug delivery, while it decreases tumor blood flow, in a rat tumor model (AH136B). Beraprost sodium (BPS) is an analogue of PGI2 that is more stable than parental PGI2 in vivo (t1/2 for BPS is > 1 h vs. a few seconds for PGI2). Thus, BPS was administered to tumor-bearing rats to examine its effect on tumor vascular permeability as well as tumor blood flow. The amount of extravasation of the Evans blue-albumin complex in tumor tissue increased from two to three times, whereas tumor blood flow decreased almost 70%, in the group treated with BPS at 7 (microg/kg compared with controls. Tissue blood flow of normal organs such as the kidney and the liver did not change to a significant extent. These findings establish a new role for BPS, not only in enhancing macromolecular drug delivery, but also in reducing the blood supply to tumor tissues.

Animals↗
PubMed2003

Further evidence for endothelin as an important mediator of pancreatic and intestinal ischemia in severe acute pancreatitis.

INTRODUCTION: Severe acute pancreatitis is occasionally associated with pancreatic and intestinal necrosis. Mesenteric vasoconstriction is one of the most probable types of pathogenesis of these complications. AIM: To investigate the involvement of endothelin-1 (ET-1), a potent vasoconstrictor. METHODOLOGY AND RESULTS: Plasma ET-1 concentrations were extremely high in patients with pancreatic and/or diffuse intestinal necrosis. ET-1 mRNA was demonstrated in the rat pancreas, and the production of ET-1 protein by human umbilical vein endothelial cells was enhanced by tumor necrosis factor-alpha, thrombin, and protease-activated receptor-2-activating peptide. Administration of ET-1 in vivo induced mesenteric arterial spasm and decreased pancreatic and intestinal blood flow. CONCLUSION: These results suggest the following: ET-1 is produced in and around the pancreas, mainly by endothelial cells, in severe acute pancreatitis; in the inflammatory setting, cytokines, activated thrombin and trypsin, may stimulate ET-1 production in a paracrine fashion; produced ET-1 may exaggerate the splanchnic microcirculation; and progressive ischemia may lead to necrosis of the pancreas and intestine.

Acute Disease↗