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Masanori Sugiyama

Publications and source records attributed to Masanori Sugiyama.

At least 19 recordsLinked to original sources
PubMed2006

Identification and kinetic study of tyrosinase inhibitors found in sake lees.

The present study found that the n-hexane extract of freeze-dried sake lees inhibits tyrosinase activity and showed that the constituents isolated from the n-hexane extract are the mixture of triacylglycerols. The inhibitory effects of triolein and trilinolein found as the triacylglycerols were examined using tyrosinases from mushroom and Streptomyces castaneoglobisporus. The IC50 values of the triacylglycerol mixture for the oxidase activity on mushroom and Streptomyces tyrosinases were 20 and 0.14 microg/mL, respectively. The IC50 values of trilinolein for the oxidase activity on mushroom and Streptomyces tyrosinases were 8.4 and 0.1 microM, respectively. However, the inhibitory effect of triolein (IC50=30 microM) was lower than that of trilinolein, even when the Streptomyces tyrosinase was used for the assay. Kinetic analyses indicate that both trilinolein and triolein inhibit the tyrosinase activity noncompetitively. When transformed with a plasmid carrying the Streptomyces tyrosinase gene, the melanin-synthesizing ability of the transformed Escherichia coli host was dose-dependently interfered with by trilinolein.

Agaricales↗
PubMed2006

Effect of a selective thromboxane A2 synthetase inhibitor on the systemic changes induced by circulating pancreatic phospholipase A2.

BACKGROUND: In acute pancreatitis, pancreatic phospholipase A(2) (PLA2) in the circulating blood hydrolyzes phospholipids contained in plasma lipoproteins, liberating eicosanoid precursors that are subsequently converted to various eicosanoids. The pathophysiological significance of eicosanoid synthesis via this pathway is unknown. The aim of this study was to clarify the role of thromboxane A(2) (TXA(2)) synthesis by circulating pancreatic PLA(2) in the pathogenesis of the systemic complications of acute pancreatitis. METHODS: Guinea pigs were divided into two groups: a control group and an ozagrel group, which received intravenous administration of ozagrel, a selective TXA(2) synthetase inhibitor. Pancreatic PLA(2) was infused intravenously in both groups for 30 min, and systemic changes during the infusion were examined. RESULTS: In the control group, there was an increase in plasma thromboxane B(2) (TXB(2)) concentration, a decrease in mean arterial pressure and heart rate, a decrease in arterial base excess (BE), bicarbonate concentration (HCO(3) (-)), and pH, a decrease in platelet count and plasma fibrinogen concentration, and a shortened prothrombin time during the infusion of pancreatic PLA(2). In the ozagrel-treated group, changes in plasma TXB(2) concentration, BE, HCO(3) (-), and platelet count were significantly inhibited. CONCLUSIONS: TXA(2) synthesis by circulating pancreatic PLA(2) contributes to metabolic acidosis and thrombocytopenia during acute pancreatitis.

Acute Disease↗
PubMed2006

Purification and characterization of the second Streptomyces phospholipase A2 refolded from an inclusion body.

A secreted phospholipase A(2) (PLA(2)) from Streptomyces violaceoruber A-2688, previously identified by us, is the first PLA(2) identified in prokaryotes. Genome sequence data of Streptomyces coelicolor A3(2) indicates that the bacterium carries two genes encoding hypothetical PLA(2)s, which exhibit 100 and 78% identity, respectively, to the S. violaceoruber PLA(2). In this study, we named the former and latter proteins as the first and second PLA(2)s, respectively. When the second PLA(2) was expressed in Escherichia coli cells, it formed an inclusion body. The present study demonstrates a method to purify it to homogeneity without the disappearance of the enzymatic activity: the inclusion body was washed with sodium deoxycholate and dissolved in the presence of 2 M urea at pH 12, then refolded by the dilution method. The refolding of enzyme was confirmed by the circular dichroism spectrum. The second PLA(2) purified to homogeneity had the same specific activity as that of the S. violaceoruber PLA(2) and the yield was approximately 6.8 mg/L culture. The second PLA(2) exhibits similar enzymatic properties to the S. violaceoruber PLA(2), except that the former enzyme does not utilize phophatidic acid as a substrate. The surface electrostatic potential of the S. coelicolor PLA(2) model, which is created by the computer-homology modeling, suggests that the positively charged surface of the enzyme does not affect the substrate specificity.

Amino Acid Sequence↗
PubMed2006

The mitomycin C (MMC)-binding protein from MMC-producing microorganisms protects from the lethal effect of bleomycin: crystallographic analysis to elucidate the binding mode of the antibiotic to the protein.

Antibiotic-producing microorganisms must be protected from the lethal effect of their own antibiotic. We have previously determined the X-ray crystal structure of the bleomycin (Bm)-binding protein, designated BLMA, as a self-resistance determinant from Bm-producing Streptomyces verticillus, which suggests that the binding of the first Bm to one of two pockets formed in the BLMA homodimer induces the cooperative binding of the second Bm to the other pocket. In the present study, we noticed that the X-ray crystallographic structure of a self-resistance determinant from a mitomycin C-producing microorganism, designated MRDP, reveals similarity to the folding pattern on the BLMA, although no sequence homology exists. To clarify the hypothesis that MRDP may function as a resistance determinant to Bm, we characterized and determined the crystal structure of MRDP complexed with the Cu(II)-bound form of BmA(2) grouped into the Bm family of antibiotics. The biochemical and structural studies for Bm binding provide evidence that the first Bm binds anti-cooperatively to a pocket of MRDP with binding affinity of the nanomolar order, whereas the second Bm binds to the other pocket, which has binding affinity of the micromolar order. The invisibility of the second Bm in the structure agrees with the observation that Escherichia coli-expressing MRDP displays lower resistance to Bm than that expressing BLMA. The structure of MRDP, which is complexed with the Cu(II)-bound BmA(2), revealed that the gamma-aminopropyldimethylsulphonium moiety of the antibiotic is sandwiched between the peripheral residues of the binding pocket and that its positively charged sulphonium head is accommodated completely in the negatively charged region of the MRDP pocket. Furthermore, the Cu(II)-bound BmA(2) has a very compact structure, in which the bithiazole ring of BmA(2) is folded back to the metal-binding domain.

Bacterial Proteins↗
PubMed2006

Crystallographic evidence that the dinuclear copper center of tyrosinase is flexible during catalysis.

At high resolution, we determined the crystal structures of copper-bound and metal-free tyrosinase in a complex with ORF378 designated as a "caddie" protein because it assists with transportation of two CuII ions into the tyrosinase catalytic center. These structures suggest that the caddie protein covers the hydrophobic molecular surface of tyrosinase and interferes with the binding of a substrate tyrosine to the catalytic site of tyrosinase. The caddie protein, which consists of one six-strandedbeta-sheet and one alpha-helix, has no similarity with all proteins deposited into the Protein Data Bank. Although tyrosinase and catechol oxidase are classified into the type 3 copper protein family, the latter enzyme lacks monooxygenase activity. The difference in catalytic activity is based on the structural observations that a large vacant space is present just above the active center of tyrosinase and that one of the six His ligands for the two copper ions is highly flexible. These structural characteristics of tyrosinase suggest that, in the reaction that catalyzes the ortho-hydroxylation of monophenol, one of the two Cu(II) ions is coordinated by the peroxide-originated oxygen bound to the substrate. Our crystallographic study shows evidence that the tyrosinase active center formed by dinuclear coppers is flexible during catalysis.

Amino Acid Sequence↗
PubMed2006

Preoperative endoscopic pancreatic stenting for prophylaxis of pancreatic fistula development after distal pancreatectomy.

BACKGROUND AND OBJECTIVE: Pancreatic fistula is a common complication of distal pancreatectomy (DP). Although various surgical procedures have been proposed for DP in an attempt to decrease the high incidence of pancreatic fistula, the prevention of pancreatic fistula remains a major problem in DP. Endoscopic pancreatic stenting for the treatment or prophylaxis of such a fistula has been rarely described. METHODS: We reviewed 9 patients who underwent preoperative endoscopic pancreatic stenting for the prophylaxis of pancreatic fistula development after DP. RESULTS: Preoperative endoscopic pancreatic stenting was successfully performed with a 7F stent in all the 9 patients. Two patients, both with intraductal papillary mucinous tumor, developed mild acute pancreatitis after the stent placement. None of the 9 patients developed pancreatic fistula. The pancreatic stent was removed from 8 to 28 days (mean 11 days) postoperatively. CONCLUSIONS: Preoperative endoscopic pancreatic stenting may be an effective prophylactic measure against pancreatic fistula development following DP in selected patients.

Adenocarcinoma, Mucinous↗
PubMed2006

Anatomic study of the superior right colic vein: its relevance to pancreatic and colonic surgery.

BACKGROUND: This study was designed to describe the precise anatomic venous tributaries of the superior mesenteric vein with special emphasis on the superior right colic vein (SRCV), which is seldom mentioned in the literature. METHODS: Nine adult cadavers were dissected to define the venous tributaries of the superior mesenteric vein. The SRCV, middle colic vein, and right colic vein (RCV) were defined as those that drained from the marginal vein of the right flexure of the colon, the transverse colon, and the ascending colon, respectively. RESULTS: The SRCV was observed to drain from the right flexure of the colon to the confluence of the right gastroepiploic and superior pancreaticoduodenal veins and present the gastrocolic trunk of Henle (GTH) in 8 of 9 cases. The RCV terminated into the GTH in 4 cases. The SRCV, the RCV, and the middle colic vein formed a confluence and entered into the GTH in 1 case. CONCLUSIONS: The SRCV exits and drains from the right colonic flexure to the GTH in 89% of cases.

Adult↗
PubMed2006

Gallstone disease: Management of intrahepatic stones.

Hepatolithiasis (oriental cholangiohepatitis) has reportedly been endemic only in East Asia. The disease is now occasionally recognized in Western societies, especially in people who have lived in the Orient. Hepatolithiasis is characterized by its intractable nature and frequent recurrence, requiring multiple operative interventions, which is in distinct contrast to gallbladder stones. In addition to frequent cholangitis and chronic sepsis, it is widely known that longstanding intrahepatic stones lead to intrahepatic cholangiocarcinoma. Symptoms of hepatolithiasis include abdominal pain, jaundice and cholangitis. Pyogenic cholangitis due to strictures and hepatolithiasis tends to recur, and sometimes patients may present with liver abscesses. Radiological studies and percutaneous procedures are keys in the diagnosis and treatment of hepatolithiasis. Non-invasive imaging modalities such as ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) accurately depict the normal anatomy and presence of intrahepatic stones. It should be stressed that each modality has its pros and cons, and imaging studies should be performed on the basis of understanding the pathophysiology. As the diagnostic role of magnetic resonance cholangiopancreatography (MRCP) evolves, the roles of both endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic cholangiography (PTC), and their most significant advantage, is primarily therapeutic with their ability to extract stones, biopsy intraductal lesions, and place stents easily. The primary goals of treatment are to eliminate attacks of cholangitis and to stop the progression of the disease (which leads to biliary cirrhosis). Surgery has a primary role in hepatolithiasis because hepatolithiasis tends to recur, so that multiple sessions of the endoscopic approach (i.e. two or three times a year) are often required. PTC is an alternative when surgical resection of the affected lobe is difficult. Techniques for lithotripsy, including shockwave and laser, can be applied in endoscopic sessions, offering a better chance of clearing the stones.

Bile Ducts, Intrahepatic↗
PubMed2006

Distribution of lymphatic vessels in the neural plexuses surrounding the superior mesenteric artery.

OBJECTIVES: To investigate whether lymphatic vessels exist in the neural plexuses surrounding the superior mesenteric artery (SMA) and the ultrastructural relationship between neural plexuses and lymphatic vessels. METHODS: A total of 970 serial sections including the structure surrounding the SMA were obtained from 9 cadavers. They were subjected to conventional hematoxylin/eosin staining and immunostaining for the lymphatic marker D2-40. Epithelial membrane antigen and S100 were also immunostained to identify the perineurium and nerve bundles, respectively. RESULTS: Thin-walled, erythrocyte-free vessels staining with lymphatic markers (D2-40) were found in the neural plexuses surrounding the SMA along a full circumference. There seemed to be a distribution correlation between lymphatic vessels and neural plexuses. Lymphatic vessels were not identified within the nerve bundles. The plexuses contained no lymph nodes in any sections. CONCLUSIONS: To our knowledge we report the immunohistochemical visualization of lymphatic vessels in peri-SMA neural plexuses for the first time. Therefore, particular attention should be paid to the lymphatic vessels within neural plexuses as a possible route of invasion and the source of pancreatic cancer recurrence.

Aged↗
PubMed2006

Actual number of tumor budding as a new tool for the individualization of treatment of T1 colorectal carcinomas.

BACKGROUND AND AIM: Treatment of T1 colorectal carcinomas, either local excision including endoscopic polypectomy or radical surgery, has always been problematic in everyday practice. Although previous studies have revealed that tumor budding at the invasive margin can be a marker for the malignant potential of T1 colorectal carcinomas, the evaluation of tumor budding has not been standardized as yet. In the present study, we attempted to apply the actual number of tumor budding units for the individualization of treatment in T1 colorectal carcinomas. METHODS: In 76 T1 colorectal carcinomas, associations between lymph node metastasis and clinicopathological parameters were examined statistically. A mathematical formula for predicting the risk of lymph node metastasis was constructed and decision analysis was attempted to determine individually the indication for additional surgery after endoscopic mucosal resection of T1 colorectal carcinomas. RESULTS: Of the clinicopathological parameters examined, multivariate analysis showed that the actual number of tumor budding units alone was significantly associated with lymph node metastasis. The probability of lymph node metastasis was calculated as Z = 0.07 x (budding counts) - 3.726, probability = 1/1 + e(-Z). The more the budding counts, the higher the probability of lymph node metastasis. This formula was able to accurately predict lymph node metastasis in successive cases. The actual number of tumor budding units can be applied to decision analysis in determining an indication for additional surgery after endoscopic mucosal resection of T1 colorectal carcinomas. CONCLUSIONS: The actual number of tumor budding units may be useful in the decision making for patient-oriented treatment of T1 colorectal carcinomas.

Adult↗
PubMed2006

Pancreatic carcinoma that completely obstructs the Wirsung duct without dilatation of the main pancreatic duct.

BACKGROUND AND AIM: Pancreatic carcinomas in which the main pancreatic duct (MPD) is completely obstructed are almost always associated with dilatation of the upstream MPD. However, some carcinomas are not associated with MPD dilatation despite complete MPD obstruction. This paradoxical phenomenon has not been well documented. METHODS: The findings from endoscopic retrograde cholangiopancreatography in 207 cases of pancreatic head carcinomas were analyzed with special reference to this unique type of carcinoma. Twenty-five of the patients were found to exhibit no MPD dilatation on ultrasonography, computed tomography or magnetic resonance imaging. RESULTS: Pancreatography via the major papilla showed complete obstruction of the MPD (112 patients with MPD dilatation and 6 without), stenosis (70 and 10, respectively), or no abnormal findings (0 and 9, respectively). In all six patients with complete MPD obstruction but without upstream MPD dilatation, injection of the minor papilla revealed a non-dilated dorsal pancreatic duct. The size of the obstructive carcinomas with and without MPD dilatation was comparable. CONCLUSIONS: Some (3%) pancreatic head carcinomas are not associated with MPD dilatation despite complete obstruction of the Wirsung duct. In such cases, the Santorini duct drains the dorsal pancreatic duct, completely compensating for the obstructed Wirsung duct. Attention should be paid to this unique type of carcinoma in diagnosing pancreatic head carcinomas.

Adenocarcinoma↗
PubMed2006

Molecular cloning and characterization of gene encoding novel puromycin-inactivating enzyme from blasticidin S-producing Streptomyces morookaensis.

Puromycin (PM) is classified into a family of nucleoside antibiotics together with blasticidin S (BS). PM-producing Streptomyces alboniger is known to express a PM-inactivating enzyme as a self-resistance determinant, which catalyzes the acetylation of PM. We have shown that, although BS-producing Streptomyces morookaensis also produces a PM-inactivating enzyme, it catalyzes the hydrolysis of an amide linkage between the aminonucleoside and O-methyl-L-tyrosine moiety of PM. In the present study, we cloned and characterized a gene encoding PM hydrolase (PMH) from BS-producing S. morookaensis JCM4673. The nucleotide sequence analysis suggests that an open reading frame consisting of 1986 bp is a gene for PMH and encodes a protein consisting of 662 amino acids with a calculated molecular mass of 71,260 Da. The molecular mass of the recombinant PMH, which was produced using an Escherichia coli host-vector system, was the same as that of PMH purified from the JCM4673 strain. Our biochemical study of the recombinant PMH confirmed that the enzyme is an aminopeptidase with broad substrate specificity. The putative primary structure of PMH contains a Gly-X-Ser-X-Gly motif, which is commonly observed among serine proteases. In addition, the amino acid sequence of PMH displays a high similarity to that of the Streptomyces acyl-peptide hydrolase (ACPH), which is a member of the prolyl oligopeptidase (POP) family of serine proteases. Furthermore, the catalytic triad (Ser-Asp-His), which is observed in the POP family, is also present in the primary structure of PMH. These results suggest that PMH is an aminopeptidase classified into the POP family.

Amino Acid Sequence↗
PubMed2006

A gene encoding a family with sequence similarity 84, member A (FAM84A) enhanced migration of human colon cancer cells.

Using genome-wide cDNA microarray analysis, we identified a number of genes whose expression was up-regulated frequently in colorectal cancer. One of these was a gene termed FAM84A that was not expressed in any of the 23 normal tissues examined except the testis. Although immuno-cytochemical staining revealed localization of FAM84A protein in the subcellular membrane region, the staining was limited to the region lacking attachment with neighboring cells. In addition, we found that exogenous FAM84A expression increased cell motility in NIH3T3 cells, and that phosphorylation of serine 38 of FAM84A was associated with morphology of cells. Our results indicate a possibility that up-regulation of FAM84A plays a critical role in progression of colon cancer.

Animals↗
PubMed2005

Tumor budding and evidence-based treatment of T2 rectal carcinomas.

BACKGROUND: The validity of the histological criteria in deciding additional bowel resection after local excision of T2 rectal carcinomas is questioned. METHODOLOGY: In 72 T2 colorectal carcinomas resected by major surgery, the associations between lymph node metastasis (LNM) and clinicopathologic parameters were examined statistically, a prediction formula for LNM was constructed and decision analysis was attempted. RESULTS: Multivariate analysis showed that female gender and a greater number of tumor budding were significantly associated with LNM. The probability of LNM can be calculated as follows; Z = 0.037 x (budding number) + 2.08 x (SEX; male, 1; female, 2) - 5.736; Probability = 1/1 + e(-Z). When a 75-year-old patient has pulmonary complications, the operative risk is assumed to be over 2%. If a number of tumor budding is 0, the risk of LNM is calculated as 2.4% in a male and 17.1% in a female patient. On the assumption that the risk of liver metastasis is half of that of LNM, and the salvageabilities after LNM and liver metastasis are 20% and 50%, respectively, observation policy is justified for a male patient, whereas additional surgery should be undertaken for a female patient. CONCLUSIONS: A number of tumor budding may be useful for determining the individualized treatment of T2 rectal carcinomas.

Cell Differentiation↗
PubMed2005

Impact of lateral pelvic lymph node dissection on evacuatory and urinary functions following low anterior resection for advanced rectal carcinoma.

BACKGROUND AND AIM: Lateral pelvic lymph node dissection (LPLD) has been reported to be beneficial in terms of survival for locally advanced low rectal carcinoma. However, the impact of LPLD on bowel function has not yet been determined by means of anorectal physiologic investigation. PATIENTS AND METHODS: Fifty-seven rectal cancer patients who underwent low anterior resection were evaluated with clinical and physiologic parameters. Of these, 15 patients had LPLD. The postoperative bowel and urinary function were evaluated with patients' questionnaire and anorectal manometry before and after the operation. RESULTS: The proportion of patients who had pouch reconstruction, adjuvant radiation therapy, and autonomic nerve dissection were significantly higher in the LPLD group. The incidence of evacuatory dysfunction was significantly higher (80% vs 45%) postoperatively in the LPLD group. There was no significant difference in anal sphincter pressures, sensory threshold, and neorectal volumes between the groups postoperatively. In terms of urinary function, use of medication for urination was significantly frequent in the LPLD group. Multivariate analysis identified the level of anastomosis as an independent affecting factor for evacuatory dysfunction and LPLD for urinary dysfunction. CONCLUSION: Although LPLD affected urinary dysfunction, it did not impair postoperative evacuatory function in the early postoperative period.

Adult↗