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T Terada

Publications and source records attributed to T Terada.

At least 289 records · Page 16Linked to original sources
PubMed1993

Synthesis of CMP-deaminoneuraminic acid (CMP-KDN) using the CTP:CMP-3-deoxynonulosonate cytidylyltransferase from rainbow trout testis. Identification and characterization of a CMP-KDN synthetase.

The sugar nucleotide, cytidine 5'-(3-deoxy-D-glycero-D-galacto-2-nonulosonic phosphate) (CMP-KDN) is expected to serve as a donor of KDN residues in the synthesis of KDN-containing glycoconjugates. We report here the identification and characterization of CMP-KDN synthetase, a novel enzyme responsible for synthesis of CMP-KDN from KDN and CTP. The enzyme was partially purified from the testis of rainbow trout (Oncorhynchus mykiss), where KDN gangliosides were first discovered (Yu, S., Kitajima, K., Inoue, S., and Inoue, Y. (1991) J. Biol. Chem. 266, 21929-21935), and used to synthesize CMP-[14C]KDN, which was characterized by 1H NMR. Vmax/Km studies showed that KDN was a preferred nonulosonic acid substrate compared to N-acetylneuraminic acid (Neu5Ac) or N-glycolylneuraminic acid (Neu5Gc) (4.4 x 10(-3) min-1 for KDN versus 2.3 and 1.8 x 10(-3) min-1 for Neu5Ac and Neu5Gc, respectively). CMP-KDN synthetase activity was maximal at pH 9-10 and at 25 degrees C. The presence of either Mg2+ or Mn2+ was essential for CMP-KDN synthetase activity. 25 mM Mg2+ stimulated formation of CMP-KDN more than 10-fold, yet only stimulated formation of CMP-Neu5Ac and CMP-Neu5Gc 4-fold, relative to 1 mM Mg2+. A kinetic study using mixed substrates showed that both CMP-KDN and CMP-Neu5Ac synthetase activities in the partially purified enzyme were due to the same active site of a single enzyme. In contrast, Neu5Ac and Neu5Gc were the preferred nonulosonic acid substrates for the calf brain CMP-sialic acid synthetase. Thus, mammalian CMP-sialic acid synthetases recognizes similar, yet distinctively different, substrate specificity determinants. Thus, the trout testis enzyme was considered to synthesize activated sugar nucleotides required for synthesis of both (KDN)GM3 and (Neu5Ac)GM3. The expression of CMP-KDN synthetase was shown to be temporally correlated with development and to parallel the developmental expression of (KDN)GM3 in sperm.

Animals↗
PubMed1993

Histological evaluation of the intrahepatic biliary tree in intrahepatic cholesterol stones, including immunohistochemical staining against apolipoprotein A-1.

Apolipoprotein A-1 is known to be one of inhibiting factors of cholesterol nucleation in bile, and decreased activity of apolipoprotein A-1 is considered to predispose cholesterol-supersaturated bile to formation of cholesterol crystals. To study the pathogenesis of the intrahepatic formation of cholesterol stones, we examined surgically resected liver specimens from six patients with intrahepatic cholesterol stones and compared the characteristic histopathological features with those of intrahepatic calcium bilirubinate stones, using morphological examination and immunohistochemical staining against apolipoprotein A-1. Morphologically, in all six patients with cholesterol stones the severity of chronic proliferative cholangitis with proliferation of the mucus-producing glandular elements in the walls of the large bile duct or periductal tissues was less extensive than that seen with calcium bilirubinate stones, and cholesterol crystals had formed in the septal and interlobular bile ducts. Immunohistochemically, unlike the normal liver and calcium bilirubinate stone-containing lobes, the hepatocytes and the epithelial lining of the bile ducts and peribiliary glands of the cholesterol stone-containing lobes did not react completely (some of the epithelial cells reacted only faintly) with apolipoprotein A-1 antibody. These findings suggest that an abundance of mucous substance and bacterial infection of the biliary tree may not be necessary for the formation of cholesterol stones, compared with findings in cases of calcium bilirubinate stones. We suggest that cholesterol crystals may be produced in the septal and interlobular bile ducts in the microenvironment of cholesterol-supersaturated bile and decreased activity of apolipoprotein A-1.

Adult↗
PubMed1993

Extrahepatic peribiliary glands express alpha-amylase isozymes, trypsin and pancreatic lipase: an immunohistochemical analysis.

We examined expression of alpha-amylase isozymes (pancreatic and salivary), trypsin and pancreatic lipase on the epithelium of extrahepatic peribiliary glands immunohistochemically using 53 autopsied normal extrahepatic bile ducts. Three parts of the extrahepatic bile duct (common bile duct, intrapancreatic bile duct and bile duct at the ampulla of Vater) were examined in each case. Histologically, the extrahepatic bile duct harbored branched tubular glands (extrahepatic peribiliary glands). Extrahepatic peribiliary glands were few in the common bile duct and intrapancreatic bile duct and numerous in the bile duct at the ampulla of Vater. Immunohistochemically, pancreatic alpha-amylase was expressed in the epithelium of extrahepatic peribiliary glands in 42 cases (79%). Salivary alpha-amylase was expressed in the epithelium of the glands in 38 cases (72%). Trypsin was expressed in the epithelium of the glands in 32 cases (60%). Pancreatic lipase was expressed in the epithelium of the glands in 45 cases (85%). The immunoreactivity of these enzymes was granular and located in the supranuclear cytoplasm (corresponding to the Golgi apparatus) of the epithelium of the glands. We confirmed the specificity of the immunoreactivity of these enzymes with various methods. These results suggest that extrahepatic peribiliary glands produce alpha-amylase isozymes, trypsin and pancreatic lipase and secrete these enzymes into lumens of the extrahepatic bile duct. The secreted enzymes may play an important role in the physiology of the extrahepatic bile duct and bile.

Adult↗
PubMed1993

Modulation of glutathione S-transferase activity by a thiol/disulfide exchange reaction and involvement of thioltransferase.

Low concentrations of cystamine and cystine inactivated human placenta glutathione S-transferase (GST-pi) in cytosolic fraction very effectively, as did the purified enzyme, through the thiol/disulfide exchange reaction. Mixed disulfide formation of GST-pi in cytosol was prevented by thioltransferase existing in cytosol with a low concentration of GSH. This protection of GST-pi activity was more effective with the participation of glutathione reductase. The incorporation of half-[14C]cystine into a GST-pi molecule according to the inactivation was provided by autoradiography. Purified human placenta thioltransferase (1900-fold from cytosol) could release the incorporated half-[14C]cystine from a GST-pi molecule with restoration of enzyme activity. Thioredoxin in placenta cytosol could not protect the GST-pi activity from inactivation at all.

Chromatography, Affinity↗
PubMed1993

Difference in glutathione S-transferase response to oxidative stress between porcine and bovine lens.

Porcine and bovine lens GSTs were compared in the stability against various oxidative stress which is a major factor of cataract formation in order to clarify the role of lens glutathione S-transferase (GST) and its relation to cataractogenesis. Class pi porcine lens GST was inactivated reversibly by biological disulfides, cystine and cystamine, and also inactivated by active oxygen species such as O2- generated through xanthine-xanthine oxidase system and H2O2. On the other hand, class mu bovine lens GST was insensitive to such applied oxidative stress. Furthermore, 1,2-naphthoquinone, which is a metabolite of naphthalene and an actual inducer of naphthalene cataract, strongly inactivated porcine lens GST though it did not affect bovine enzyme. Thus, porcine and bovine lens GSTs had different sensitivity to various oxidative stress which could induce cataract formation. The results suggest that the differential expression of GST isozymes among animals may explain the variation in the cataract formation caused by oxidative stress.

Animals↗
PubMed1993

Histopathological and morphometric analysis of atypical adenomatous hyperplasia of human cirrhotic livers.

Atypical adenomatous hyperplasia (AAH) is a hyperplastic parenchymal nodular change in the cirrhotic liver, in which overt hepatocellular carcinoma (HCC) occasionally arises. AAH is defined as a sizable hepatocellular nodule with a variable degree of hepatocellular atypia not regarded as HCC, and is different from ordinary adenomatous hyperplasia in which hepatocellular atypia is absent. In the present study, we attempted to evaluate carcinogenetic processes and to find histological variables which indicate malignant transformation in AAH, using 49 surgically resected or autopsied nodules. AAH frequently showed morphological heterogeneity. Atypical lesions within AAHs were divisible into the following three categories from overall histopathological appearances: malignant (A), equivocal (B), or non-malignant (C) lesions. Analysis of combination of these three lesions, which were frequently intermixed in a given AAH, suggested that B lesions appear subsequent to C lesions, and A lesions finally appear in AAH nodules. Among the 14 histological variables, enlargement, hyperchromasia and irregular contour of nuclei were found to correlate well with A lesions. Increased nuclear density, iron resistance, reduction of reticulin fibres, clear cell change, sinusoidal dilatation and presence of abnormal arteries were suggestive of A or B lesions. Nuclear deviation toward the sinusoids, acinar and compact arrangements, fatty change and Mallory's hyaline alone were not useful indicators of A or B lesions. These results indicate that AAH is a preneoplastic or borderline lesion in which overt HCC is likely to evolve through several steps. Although a needle liver biopsy is a useful tool for diagnosis of benign, equivocal and malignant hepatocellular nodular lesions, the needle biopsy specimen should be carefully evaluated by considering the morphological heterogeneity of the AAH and a variable combination of 14 histological variables.

Aged↗
PubMed1993

Adenomatous hyperplasia of the liver resembling focal nodular hyperplasia in patients with chronic liver disease.

Two nodules of hepatic adenomatous hyperplasia (AH) resembling focal nodular hyperplasia were found in two patients with cirrhosis or chronic active hepatitis. Imaging techniques suggested that the nodules were hepatocellular carcinoma. Pathological examination showed that the nodules (approximately 1.0 cm in diameter) were clearly demarcated from the surrounding liver tissue, and contained foci of scar-like fibrosis in the centre of the nodules. Microscopically, they contained portal tracts and fulfilled the criteria of AH. A large number of arteries were present in the central scar-like fibrosis as well as in the parenchyma of the nodules. There were foci of mildly atypical hepatocytes in one nodule but no cellular atypia in the other. Morphometric analysis showed that the cumulative luminal area of arteries per unit area was much greater in the nodules than in the extranodular liver tissues, while the cumulative luminal area of portal veins per unit area was much less in the nodules than in the extranodular liver tissues. Although the pathogenesis is unclear, these nodules might have developed through localized vascular changes associated with chronic liver disease, may have arisen from pre-existing arterial malformation, or may represent the early stages of angiogenesis in hepatocarcinogenesis.

Adenoma↗
PubMed1993

The coexistence of cancer cells of different origin within the same lymph nodes.

The coexistence of two differently originating cancer cells within the same lymph node is reported. An 83-year-old male patient died from severe carcinomatous lymphangitis of the lungs five months after gastrectomy for gastric cancer. At autopsy, prostatic cancer metastasis to lymph node was found. Histologically, the prostatic carcinoma cells had a cribriform pattern and the gastric cells showed papillary and tubular features. Immunohistochemically, the former was immunoreactive to prostate specific antigen (PSA) and the latter was stained positively for carcinoembryonic antigen (CEA). Fifty-one of the retroperitoneal and intrapelvic lymph nodes were histologically examined; the coexistence of both types of cancer cells was found in two lymph nodes. Both types were adjoined at the hilum, as was also confirmed by an immunohistochemical double staining technique. These two lymph nodes were located in the pre-aortic and left lateral aortic areas, and they belonged to the terminal lymph node group of both the intra-pelvic and intra-abdominal intestinal organs.

Adenocarcinoma↗
PubMed1993

A case of serous cystadenoma of the pancreas with focal malignant changes.

We present a serous cystadenoma of the pancreas with focal malignant changes, and describe its characteristic histological features. On gross examination, a tumor was present on the anterior surface of the body of the pancreas and measured approx 25 x 25 x 20 mm. Microscopically, most tumor cells showed the typical histological features of serous cystadenoma, characterized by a microcystic architecture and glycogen-rich cells with a uniform and bland appearance. However, in some areas, a tendency to papillary structures with fibrovascular cores was noted. These papillary lesions were composed mainly of nonmucinous, glycogen-poor epithelial cells, the nuclei of which showed a mild atypia. In addition, vascular and perivascular invasion was focally observed. However, there was no clinical evidence of local or distant metastasis. From these findings, we diagnosed this lesion as a serous cystadenoma of the pancreas with focal malignant changes rather than a serous cystadenocarcinoma of the pancreas.

Blood Vessels↗
PubMed1993

Expression of argyrophilic nucleolar organizer regions in ductal adenocarcinoma of the pancreas and its relationship to prognosis.

The aim of the present study was to investigate the relationship between Ag-NOR count levels and survival in 33 patients undergoing resection for ductal adenocarcinoma of the pancreas at Kanazawa University Hospital from 1985 to 1991. To determine the biologic behavior of invasive ductal adenocarcinoma of the pancreas, 33 tumors were classified into two groups according to the median value of Ag-NOR counts: Group 1, Ag-NOR count > or = 3.25 (higher Ag-NOR count group); Group 2, Ag-NOR count < 3.25 (lower Ag-NOR count group). As a result, we found that tumors with a higher Ag-NOR count were more likely to have liver or peritoneal metastasis than those with a lower Ag-NOR count, although the differences were not statistically significant. Tumors with lower Ag-NOR count levels were associated with favorable prognoses 2 and 3 yr after surgery, whereas those with higher Ag-NOR count levels were related to poor prognosis. Our results indicate that a Ag-NOR count level is a reliable prognostic parameter in resected pancreatic ductal adenocarcinoma.

Adult↗
PubMed1993

Biliary papillomatosis with the point mutation of K-ras gene arising in congenital choledochal cyst.

Biliary papillomatosis is a rare entity. A case of biliary papillomatosis associated with congenital choledochal cyst and intrahepatic gallstones is reported here. Percutaneous transhepatic cholangioscopy revealed multiple papillary lesions of the right intrahepatic duct and the common bile duct. Microscopically, the papillary mucosal lesion showed papillary proliferations of bile duct epithelial cells with mild atypia. Furthermore, a point mutation at codon 12 of the K-ras oncogene was found in the papillary lesion. To the best of our knowledge, this is the first case of biliary papillomatosis arising in congenital choledochal cyst. Although the pathogenesis of biliary papillomatosis in our case was unclear, biliary irritation associated with choledochal cyst may be related to biliary papillomatosis with point mutation at codon 12 of K-ras gene.

Aged↗
PubMed1993

Purification and characterization of carbonyl reductases from bovine liver cytosol and microsome. The cytosolic enzyme has a novel 3 alpha/17 beta-hydroxysteroid dehydrogenase activity.

1. Carbonyl reductase, which is distributed in both cytosolic and microsomal fractions in bovine liver, were purified to homogeneity on 12.5% sodium dodecylsulfate-polyacrylamide gel electrophoresis and shown to have molecular weights of 32 kDa and 68 kDa, respectively. 2. Both carbonyl reductases can catalyze the reduction of many carbonyl compounds including ketone, quinones and aldehyde with relatively low Km values. 3. From the absorption spectrum result, microsomal carbonyl reductase closely resembles cytochrome P-450 reductase. 4. Cytosolic carbonyl reductase is a novel enzyme which can act on both testosterone and androsterone at low concentration.

17-Hydroxysteroid Dehydrogenases↗
PubMed1993

A case of vessel perforation during interventional neuroradiological procedure. Operative findings of the perforated vessel.

A case of vessel perforation by a guide wire during an interventional neuroradiological procedure is reported. The patient was a 59-year-old woman with a left frontal basal arteriovenous malformation (AVM) fed by the left anterior cerebral artery. Transarterial embolization of the AVM was attempted. During the procedure, vessel perforation by the guide wire occurred at the left A1-A2 junction and resulted in subarachnoid hemorrhage, which stopped spontaneously. The patient developed progressive obstructive hydrocephalus, and surgical treatment was performed. The AVM was totally removed after ventricular drainage, and the arterial perforation site was explored. When clot around the left A1-A2 junction was removed, hemorrhage recurred. This hemorrhage was similar to what has been observed when a small perforating artery was avulsed. The hemorrhage site was coagulated under temporary occlusion of both A1 segments. Surgical intervention was probably not necessary for this type of bleeding if it had stopped spontaneously, because the rebleeding from the small pinhole would be unlikely, and the operation was more hazardous than the usual aneurysmal surgery.

Cerebral Arteries↗
PubMed1993

Complex occipital arteriovenous fistula associated with neurofibromatosis treated by embolization and surgery. Case report.

It is well known that neurofibromatosis is associated with various types of arteriovenous fistulas (AVF), but association with an occipital AVF has not been reported. We are reporting this case which was successfully treated with a combination of embolization and surgery. Superselective angiography defines the anatomic details of the fistula and intraoperative digital subtraction angiography (DSA) facilitates the surgery to cure the fistula. It is important to identify the best therapeutic options using angiographic information to treat a complex arteriovenous fistula.

Adult↗
PubMed1993

Percutaneous transluminal angioplasty for the M2 portion vasospasm following SAH: development of the new microballoon and report of cases.

A new silicone microballoon was developed for the percutaneous transluminal angioplasty of smaller intracranial vessels, such as A1, A2 and M2. This balloon was 0.5 x 2.0 mm in the deflated condition and became 2.2 x 6.5 mm inflated with 0.02 mL of fluid, and its bursting pressure was 2 atm. Two illustrative cases are presented. The first case was not treated in the M2 distribution. The second case of vasospasm of the left M2 portion was successfully treated with this new balloon, with prompt improvement of the neurological condition and cerebral circulation. The usefulness of our microballoon in treating a patient with vasospasm of small intracranial arteries is discussed.

Angioplasty, Balloon↗
PubMed1993

Expression of alpha-amylase isoenzymes and trypsin by the proliferating epithelium of large intrahepatic bile ducts and intrahepatic peribiliary glands in hepatolithiasis.

The expression of alpha-amylase isoenzymes (pancreatic and salivary) and trypsin by the epithelium of large intrahepatic bile ducts and peribiliary glands was examined immunohistochemically in hepatolithiasis (n = 22), extrahepatic biliary obstruction (n = 20) and normal liver (n = 22). Hepatolithiasis was associated with marked proliferation of bile duct cells and peribiliary glands. Expression of pancreatic and salivary amylase was observed in the proliferating bile duct cells and peribiliary glands of all livers, and trypsin was found in 68% of the livers. In extrahepatic biliary obstruction, proliferation of the biliary epithelium was less marked, but expression of amylase isoenzymes was observed in all livers and trypsin was found in 50%. All normal livers showed expression of amylase isoenzymes in large intrahepatic bile ducts, septal bile ducts and peribiliary glands, and trypsin was found in 73%. The density of enzyme-containing acini was highest in hepatolithiasis, intermediate in extrahepatic biliary obstruction and lowest in normal liver. These results show that the proliferating biliary epithelium in hepatolithiasis contains amylase isoenzymes and trypsin and that biliary epithelium retains the ability to produce these enzymes after proliferation, suggesting that a large amount of amylase isoenzyme and trypsin may be secreted into the bile ducts in hepatolithiasis. These enzymes may play an important role in the pathophysiology of hepatolithiasis.

Adult↗
PubMed1993

Adenomatous hyperplasia of the liver as a precancerous lesion.

Adenomatous hyperplasia (AH), a hyperplastic parenchymal nodule, is detected most often through radiological and pathological observations in chronic advanced liver disease. AH can be classified into two categories: ordinary type or macroregenerative nodule (MRN) type I, and atypical type or MRN type II. Characteristically, both types contain portal tracts with portal veins and biliary elements. Ordinary AH may represent a large regenerative nodule with limited growth potential. Atypical AH shows slightly cellular and structural atypia, altered phenotypic expression, and increased proliferative activity compared to the surrounding liver. Histologic differentiation of atypical AH from well-differentiated hepatocellular carcinoma (HCC) is controversial, and generally accepted diagnostic criteria are still lacking. Atypical AH occasionally contains overt malignant foci. Histological observations and portography show that nodules of AH are supplied by portal venous blood. While AH nodules appear to be hypoperfused according to arteriographic studies, atypical AH contains small arterial branches which are abundant in contrast to the surrounding liver. The data obtained so far indicate that atypical AH may be a hepatocellular neoplasm which belongs nosologically to a gray area of neoplasm, in which overt HCC is likely to develop. It is clinically recommended that atypical AH is treated as "malignant" because of the occasional inclusion of HCC foci. For its treatment, percutaneous ethanol injection is becoming popular.

Carcinoma, Hepatocellular↗