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Masao Tanaka

Publications and source records attributed to Masao Tanaka.

At least 19 recordsLinked to original sources
PubMed2006

Microbiological analysis and endoanal ultrasonography for diagnosis of anal fistula in acute anorectal sepsis.

BACKGROUND AND AIMS: Treatment of anorectal sepsis requires prompt surgical drainage, but it is important to identify any associated anal fistula for preventing recurrence. We evaluated whether microbiological analysis and/or endoanal ultrasonography could be used to predict anal fistula in patients with acute anorectal sepsis. METHODS: Five hundred fourteen consecutive patients with acute anorectal sepsis were studied. Clinical data, digital examination findings, endosonographic findings, and results of microbiological analysis were compared with definitive surgical findings of the presence or absence of anal fistula. RESULTS: Anorectal abscess with anal fistula was found in 418 patients, and anorectal abscess without anal fistula was found in 96 patients. Microbiological examination showed that Escherichia coli, Bacteroides, Bacillus, and Klebsiella species were significantly more prevalent in patients with fistula (P<0.01), and coagulase-negative Staphylococci and Peptostreptococcus species were significantly more prevalent in patients without fistula (P<0.01). Results of endoanal ultrasonography were concordant with the definitive surgical diagnosis in 421 (94%) of 448 patients studied. CONCLUSION: Acute anorectal sepsis due to colonization of "gut-derived" microorganisms rather than "skin-derived" organisms is more likely to be associated with anal fistula. When the microbiological analysis yields gut-derived bacteria, but no fistula has been found in the initial drainage operation, repeat examinations during a period of quiescence, including careful digital assessment and meticulous endosonography, are warranted to identify a potentially missed anal fistula.

Abscess↗
PubMed2006

Quantitative analysis of human telomerase reverse transcriptase in pancreatic cancer.

Although telomerase activity is a promising diagnostic marker, clinical introduction of this marker for cancer diagnosis is still problematic due to the lack of means of evaluating sample quality. Human telomerase reverse transcriptase (hTERT), one of the subunits of telomerase, is also a promising diagnostic marker. In the present study, we did large-scale analysis of 88 pancreatic juice samples to determine the feasibility of quantitative analysis of hTERT mRNA for diagnosis of pancreatic cancer. We found significant differences in hTERT expression among carcinoma-derived, intraductal papillary mucinous neoplasm (IPMN)-derived, and chronic pancreatitis-derived juice samples. Results showed that quantitative analyses of hTERT mRNAs are more useful in discriminating carcinoma from IPMN than from chronic pancreatitis. When the specificity was set at 100%, the sensitivity for differentiation between carcinoma and IPMN was 43.5%, whereas the sensitivity of cytologic examination was 22.0%. There were significant differences in hTERT expression among carcinoma cells, IPMN cells, and normal ductal cells isolated from pancreatic tissues by microdissection. Lymphocytes and hyperplastic epithelial cells isolated from tissues with the histologic appearance of pancreatitis showed various expression levels of hTERT. Our results suggest that quantitative analysis of hTERT mRNA in pancreatic juice is advantageous over cytologic analysis for differentiation between carcinoma and IPMN but probably not for differentiation between carcinoma and chronic pancreatitis.

DNA-Binding Proteins↗
PubMed2006

Postoperative urinary retention after surgery for benign anorectal disease: potential risk factors and strategy for prevention.

PURPOSE: This study was undertaken to determine the incidence of and risk factors for urinary retention after surgery for benign anorectal disease. METHODS: We reviewed 2,011 consecutive surgeries performed under spinal anesthesia for benign anorectal disease from January through June 2003 to identify potential risk factors for postoperative urinary retention. In addition, we prospectively investigated the preventive effect of perioperative fluid restriction and pain control by prophylactic analgesics on postoperative urinary retention. RESULTS: The number of procedures and the urinary retention rates were as follows: hemorrhoidectomy, 1,243, 21.9%; fistulectomy, 349, 6.3%; incision/drainage, 177, 2.3%; and sliding skin graft/lateral subcutaneous internal sphincterotomy, 64, 17.2%. The overall urinary retention rate was 16.7%. With hemorrhoidectomy, female sex, presence of preoperative urinary symptoms, diabetes mellitus, need for postoperative analgesics, and more than three hemorrhoids resected were independent risk factors for urinary retention as assessed by multivariate analysis. With fistulectomy, female sex, diabetes mellitus, and intravenous fluids >1,000 ml were independent risk factors for urinary retention. Perioperative fluid restriction, including limiting the administration of intravenous fluids, significantly decreased the incidence of urinary retention (7.9 vs 16.7%, P<0.0001). Furthermore, prophylactic analgesic treatment significantly decreased the incidence of urinary retention (7.9 vs 25.6%, P=0.0005). CONCLUSIONS: Urinary retention is a common complication after anorectal surgery. It is linked to several risk factors, including increased intravenous fluids and postoperative pain. Perioperative fluid restriction and adequate pain relief appear to be effective in preventing urinary retention in a significant number of patients after anorectal surgery.

Adult↗
PubMed2006

Quantitative analysis of MUC1 and MUC5AC mRNA in pancreatic juice for preoperative diagnosis of pancreatic cancer.

Pancreatic juice is a promising type of diagnostic sample for pancreatic cancer, and members of the mucin (MUC) family are diagnostic candidates. To evaluate the utility of MUC family members as diagnostic markers, we measured MUC mRNA expression in pancreatic tissues and pancreatic juice obtained from patients with different pancreatic diseases as well as in pancreatic cancer cell lines by real-time PCR. Furthermore, to support the possibility of early diagnosis by quantification of MUC1 and MUC5AC, immunohistochemistry and microdissection-based quantitative analysis of mRNA were carried out. There was no significant correlation between MUC1 and MUC5AC expression in cell lines. When beta-actin was used as a reference gene, median MUC1 and MUC5AC mRNA expression levels were remarkably greater in tumoral tissues than in non-tumoral tissues, but median MUC4 and MUC6 mRNA expression levels were not. Receiver operating characteristic curve analysis showed that quantitative analysis of MUC1 and MUC5AC mRNA in pancreatic juice is better diagnostic modality than that of MUC4 and MUC6 mRNA. Immunohistochemistry showed that MUC1 and MUC5AC were highly expressed in invasive ductal carcinomas (IDC) and moderately expressed in high-grade pancreatic intraepithelial neoplasia (PanIN); no staining was observed in normal ducts. Analysis of cells isolated by microdissection showed stepwise upregulation of MUC1 and MUC5AC in the development of high-grade PanIN to IDC. Our results suggest that MUC1 and MUC5AC are upregulated stepwise in pancreatic carcinogenesis and that quantitative assessment of MUC1 and MUC5AC mRNA in pancreatic juice has high potential for preoperative diagnosis of pancreatic cancer.

Biomarkers, Tumor↗
PubMed2006

Complete extirpation of a bronchogenic cyst causing recurrent laryngeal nerve palsy by thoracoscopy: report of a case.

We excised a bronchogenic cyst causing recurrent laryngeal nerve palsy using thoracoscopic surgery. A 28-year-old woman presented after the sudden onset of hoarseness, and laryngoscopic examination showed left vocal cord palsy. Computed tomography and magnetic resonance imaging showed a cystic mass, 4 cm in diameter, in the aortopulmonary window. Thoracoscopic examination revealed that the mass was adhered to the recurrent laryngeal nerve below the aortic arch. We extirpated the cyst via thoracoscopy without any injury to the nerves or major blood vessels. This case illustrates the benefits of thoracoscopic surgery for providing good visualization of the perineural structures and as a safe surgical treatment for a cystic mass in the aortopulmonary window.

Adult↗
PubMed2006

Inhibition of inducible nitric oxide synthase prevents hepatic, but not pulmonary, injury following ischemia-reperfusion of rat liver.

The aim of this study was to investigate the contribution of inducible nitric oxide synthase (iNOS)-derived nitric oxide on the liver and lung injury following hepatic ischemia-reperfusion (I/R) using a novel and potent iNOS inhibitor, ONO-1714. Rats were subjected to 90 min of partial hepatic ischemia followed by 3, 6, 12, and 24 hr of reperfusion. Expression of iNOS mRNA peaked at 3 hr of reperfusion in the liver and lung. Plasma nitric oxide levels were increased fourfold at 24 hr of reperfusion and plasma ALT was increased, reaching a peak at 12 hr of reperfusion; both were significantly inhibited by ONO-1714. Histological examination revealed extensive liver damage, whereas this was not seen in the ONO-1714 group. Lung injury was not significantly changed in groups with versus without ONO-1714. Nitrotyrosine expression was seen in regions similar to those of the histological injuries of the liver, while this staining was absent in the ONO-1714 group. These data show that generation of peroxynitrite could be involved in the pathogenesis of liver injury but not lung injury after hepatic I/R. Inhibition of iNOS could be applied for attenuation of liver injury following hepatic I/R.

Amidines↗
PubMed2006

Hepatic ischemia/reperfusion injury is prevented by a novel matrix metalloproteinase inhibitor, ONO-4817.

BACKGROUND: Matrix metalloproteinases (MMPs) play an important role in inflammation and neoplastic invasion and metastasis. Little is known about the effects of MMP inhibitors on hepatic ischemia/reperfusion injury. The aim of this study is to examine the inhibitory effects of ONO-4817 (oral inhibitor of MMPs) in rats. METHODS: Hepatic ischemia/reperfusion was induced in male Wister rats by clamping the portal vein and hepatic artery. The animals were randomized into an ONO-4817 group (300 mg/kg body weight per/day) and a vehicle group by oral gavage of a test substance. Serum alanine aminotransferase, histologic changes, gelatinolytic activity, MMP-2 and MMP-9 activities, tissue inhibitor of metalloproteinase 2 (TIMP-2) messenger RNA (mRNA) levels, and mRNA and serum levels of tumor necrosis factor alpha (TNFalpha) and interleukin 1beta (IL-1beta) were measured in both groups. RESULTS: ONO-4817 prevented ischemia/reperfusion injury to the hepatocytes as shown by significant reductions of serum alanine aminotransferase and less severe histologic changes. Gelatinolytic activity was inhibited markedly in the liver of the ONO-4817 group as demonstrated by film in situ zymography. MMP-9 and MMP-2 activities also were inhibited in the ONO-4817 group as shown by gelatin zymography. TIMP-2 mRNA levels showed no significant differences between the 2 groups. TNFalpha mRNA showed no downregulation, but IL-1beta mRNA was downregulated in the liver of the ONO-4817 group 1 to 3 hours after reperfusion. Serum levels of TNFalpha and IL-1beta showed a significant decrease in the ONO-4817 group, compared with the vehicle group after reperfusion. CONCLUSIONS: Hepatic ischemia/reperfusion injury was improved by a novel MMP inhibitor, ONO-4817, not only by inhibition of gelatinolytic activity but also by a decrease in release of inflammatory cytokines.

Animals↗
PubMed2006

Age-associated changes in viscoelastic properties of the bovine temporomandibular joint disc.

To test the hypothesis that compressive properties of the temporomandibular joint (TMJ) disc change with age, we investigated its viscoelastic properties and stress-relaxation behavior under compression. Compressive stress-relaxation tests were performed in different regions of bovine discs of various ages. For each disc, specimens were derived from three different regions (anterior, central, and posterior). For four strain levels (5, 10, 15, and 20%), a stress-relaxation test was conducted over a 5-min period. Values of the instantaneous modulus, E(0), appeared to be larger in the anterior than in the posterior region of the disc, irrespective of age. The E(0) value increased with age, especially in the central region. Values of the relaxed modulus, E(R), also increased significantly with age. There were no regional differences in values of the relaxed modulus. Under stress-relaxation, the relaxation time became longer with age, especially in the posterior region. The results suggest that the compressive properties, instantaneous and relaxed moduli, increase with age, while the relaxation time becomes longer. This implies that the TMJ disc becomes harder with age. Furthermore, the compressive properties of the TMJ disc are region-specific. As a result of the harder disc, it is likely that the TMJ becomes more vulnerable to secondary damage, such as fracture and tissue degradation.

Aging↗
PubMed2006

International consensus guidelines for management of intraductal papillary mucinous neoplasms and mucinous cystic neoplasms of the pancreas.

Non-inflammatory cystic lesions of the pancreas are increasingly recognized. Two distinct entities have been defined, i.e., intraductal papillary mucinous neoplasm (IPMN) and mucinous cystic neoplasm (MCN). Ovarian-type stroma has been proposed as a requisite to distinguish MCN from IPMN. Some other distinct features to characterize IPMN and MCN have been identified, but there remain ambiguities between the two diseases. In view of the increasing frequency with which these neoplasms are being diagnosed worldwide, it would be helpful for physicians managing patients with cystic neoplasms of the pancreas to have guidelines for the diagnosis and treatment of IPMN and MCN. The proposed guidelines represent a consensus of the working group of the International Association of Pancreatology.

Endocrine Surgical Procedures↗
PubMed2006

Natural killer T-cells participate in rejection of islet allografts in the liver of mice.

A role of natural killer T (NKT) cells in transplant rejection remains unknown. Here, we determined whether NKT cells participate in rejection of islet allografts, using NKT cell-deficient mice. Survival of islet allografts in streptozotocin-induced diabetic CD1d(-/-) mice or Valpha14 NKT cell(-/-) mice was significantly prolonged without immunosuppression when grafted into the liver, but not beneath the kidney capsule, compared with wild-type mice. Acceptance of intrahepatic islet allografts was achieved in CD1d(-/-) mice by a subtherapeutic dose of rapamycin, which was abrogated in conjunction with the transfer of hepatic mononuclear cells from wild-type, but not from CD1d(-/-), mice at islet transplantation. The second islet grafts from a donor-specific, but not from a third-party, strain in CD1d(-/-) mice bearing functional islet allografts were accepted without immunosuppression at 120 days after the initial transplantation. These findings demonstrate that NKT cells play a significant role in rejection of islet allografts in the liver of mice, but that NKT cells are not essential for induction of donor-specific unresponsiveness in this model. The current study indicates that NKT cells might be considered as a target for intervention to prevent islet allograft rejection when the liver is the site of transplantation.

Adoptive Transfer↗
PubMed2005

The role of S100A6 in pancreatic cancer development and its clinical implication as a diagnostic marker and therapeutic target.

Recent microarray analyses showed that the S100 family contains members that are candidate diagnostic markers or therapeutic targets. In the present study, to evaluate the involvement of S100A6 in pancreatic cancer and its clinical usefulness for diagnosis, we examined S100A6 mRNA expression in pancreatic tissues and pancreatic juice from patients with different pancreatic diseases. To investigate the role of S100A6 in carcinogenesis of pancreatic cancer and the potential of S100A6 as a diagnostic marker for early detection of pancreatic cancer, we did immunohistochemistry and microdissection-based mRNA analysis of pancreatic normal ducts, pancreatic intraepithelial neoplasias, and invasive ductal carcinomas. We also used in vitro experiments and microarray analysis with RNA interference to evaluate the functional role of S100A6 and its potential as a therapeutic target for pancreatic cancer. S100A6 mRNA levels were significantly higher in carcinoma specimens than in nonneoplastic tissues. In pancreatic juice, there was a significant difference in S100A6 expression between patients with carcinoma and those with nonneoplastic disease. Receiver operating characteristic curves revealed that S100A6 might be a useful marker for diagnosis of pancreatic cancer. Immunohistochemistry and microdissection-based analysis showed differential expression of S100A6 among normal ducts, pancreatic intraepithelial neoplasias, and invasive ductal carcinomas. In vitro data showed that inhibition of S100A6 decreased proliferation and invasiveness of cancer cells, and these findings were supported by microarray data. Our present results suggest that quantitation of S100A6 mRNA is a promising tool for diagnosis of pancreatic cancer, and that S100A6 may be a promising therapeutic target for pancreatic cancer.

Biomarkers, Tumor↗
PubMed2005

Suppression of metastasis of human pancreatic cancer to the liver by transportal injection of recombinant adenoviral NK4 in nude mice.

NK4, a 4-kringle fragment of hepatocyte growth factor (HGF), is an HGF antagonist that also acts as an angiogenesis inhibitor. NK4 strongly inhibits the infiltration, metastasis, and tumor growth of pancreatic cancer. The aim of our study was to evaluate the antitumor effect of adenovirus-mediated NK4 gene transfer to the liver on hepatic metastasis of pancreatic cancer in vivo. We constructed recombinant adenoviral NK4 (Ad-NK4), which encodes a secreted form of human NK4. Intrasplenic injection of Ad-NK4 induced high and relatively maintained expression of NK4 protein in the liver and suppressed the number and growth of metastatic foci in the liver in a nude mouse model. Microscopically, central necrosis was found even in small metastatic foci in Ad-NK4 treated mice. Immunohistochemical analysis of metastatic tumors showed a remarkable decrease in microvessel density and an increase in the number of apoptotic tumor cells after treatment with Ad-NK4. These results indicate that intraportal injection of Ad-NK4 may be a useful therapeutic modality for the clinical control of hepatic metastasis in pancreatic cancer.

Adenocarcinoma↗
PubMed2005

Novel bactericidal surface: Catechin-loaded surface-erodible polymer prevents biofilm formation.

We developed a novel bactericidal surface based on a catechin-loaded surface-erodible polymer. (-)-Epigallocatechin-3-gallate (EGCg), which is the main constituent of tea catechins, showed a dose-dependent inhibitory effect on Escherichia coli biofilm formation and a dose-dependent enhanced destructive effect on biofilm. EGCg-immobilized surfaces were prepared by photopolymerization of liquid biodegradable polyesters. The releasing rate was enhanced with an increase in surface-erosion rate of photocured polymers. Polymers with high releasing capacity dose-dependently reduced biofilm formation on the surfaces. The confocal laser scanning microscopic and scanning electron microscopic observations revealed that EGCg induced biofilm-destructing activities, which include bacterial membrane damage, degradation of exopolysaccharides, and detachment of colonized cells. From these results, potential advantages of the clinical use of catechin-loaded polymer-coated implants or catheters are discussed in terms of a reduced occurrence of biomaterial-centered infections without substantial toxicity or adverse effects.

Anti-Infective Agents↗
PubMed2005

Valpha14 NK T cell-triggered IFN-gamma production by Gr-1+CD11b+ cells mediates early graft loss of syngeneic transplanted islets.

Pancreatic islet transplantation is a highly promising approach for the treatment of insulin-dependent diabetes mellitus. However, the procedure remains experimental for several reasons, including its low efficiency caused by the early graft loss of transplanted islets. We demonstrate that Gr-1+CD11b+ cells generated by transplantation and their IFN-gamma production triggered by Valpha14 NKT cells are an essential component and a major cause of early graft loss of pancreatic islet transplants. Gr-1+CD11b+ cells from Valpha14 NKT cell-deficient (Jalpha281-/-) mice failed to produce IFN-gamma, resulting in efficient islet graft acceptance. Early graft loss was successfully prevented through the repeated administration of alpha-galactosylceramide, a specific ligand for Valpha14 NKT cells, resulting in dramatically reduced IFN-gamma production by Gr-1+CD11b+ cells, as well as Valpha14 NKT cells. Our study elucidates, for the first time, the crucial role of Gr-1+CD11b+ cells and the IFN-gamma they produce in islet graft rejection and suggests a novel approach to improving transplantation efficiency through the modulation of Valpha14 NKT cell function.

Animals↗
PubMed2005

Novel serum tumor marker, RCAS1, in pancreatic diseases.

AIM: As tumor markers for pancreatic carcinoma, carcinoembryonic antigen (CEA) and carbohydrate antigen (CA) 19-9 have been used, but the sensitivity and specificity are not enough for the diagnosis of pancreatic carcinoma. METHODS: A novel serum tumor marker, RCAS1, was compared with two conventional serum tumor markers, CEA (highly specific for pancreatic cancer) and CA 19-9 (highly sensitive for pancreatic cancer), in 48 patients with pancreatic exocrine tumors. RESULTS: When the diagnosis of benign or malignant conditions was examined by one tumor marker, the sensitivity of RCAS1 alone (55%) was higher than that of CEA alone (27%) and the specificity of RCAS1 alone (92%) was greater than that of CA19-9 alone (78%). When examined by a combination of two markers, the sensitivity of a combination of RCAS1 and CA19-9 (95%) was superior to those of CA19-9 alone (78%), RCAS1 alone (55%, P = 0.002), CEA alone (27%) (P<0.001), RCAS1 and CEA (59%) and CA19-9 and CEA (82%). CONCLUSION: These results suggest that the combination of RCAS1 and CA19-9 is highly sensitive for pancreatic carcinoma.

Adult↗