Search PubMed⌕ Search

Biomedical subjects

M Sugiyama

Publications and source records attributed to M Sugiyama.

At least 109 records · Page 6Linked to original sources
PubMed2000

Endonucleases.

Programmed cell death (PCD) involves hydrolysis of genomic DNA, which must be catalyzed by endonuclease(s) capable of digesting dsDNA. Plants have two major classes of endonucleases active towards dsDNA, Zn2+-dependent endonuclease and Ca2+-dependent endonuclease. Both classes are found among endonucleases nominated for machineries of PCD in plants. Survey of plant endonucleases in relation to PCD leads to a possibility that a different class of endonuclease reflects a different phase of PCD-associated DNA hydrolysis.

Amino Acid Sequence↗
PubMed2000

p53, bcl-2 and bax abnormalities in non-Hodgkin's lymphomas of the head and neck.

In the present study, mutations or protein expression of p53, bcl-2 and bax are reported in 13 non-Hodgkin's B-cell lymphomas of the head and neck. Nine of 13 cases (69.2%) expressed p53 protein and 7 (53.8%) showed gene mutations. On comparing the results of immunostaining and SSCP analysis, there were two cases showing discrepancies between the p53 protein expression and gene mutations. Bcl-2 protein expression was observed in only two cases of follicular lymphoma. On the other hand, bax protein was detected in all 13 cases. One case with mutated bax gene showed a lower expression with a reduced frequency of bax-positive cells than the other 12. These results suggest that inactivation of p53 may be closely related to development and/or progression of these NHLs, and that bcl-2 and bax protein may not have a role.

Adolescent↗
PubMed2000

A novel approach to gene therapy of albino hair in histoculture with a retroviral streptomyces tyrosinase gene.

In order to induce melanin production in mammalian cells with pigment disorders such as albino hair, a recombinant retrovirus containing the mel locus of Streptomyces antibioticus was constructed. The S. antibioticus mel locus, which consists of the open reading frame (ORF)-438 and the tyrosinase gene, was specifically derived by polymerase chain reaction (PCR) from Streptomyces plasmid pIJ702. The ORF-438 is required for the transfer of copper to apotyrosinase, which is essential for tyrosinase enzymatic activity. The tyrosinase gene was inserted into the XhoI/BamHI cloning site of the pLXSN retroviral vector to obtain pLtyrSN. An internal ribosome entry site (IRES) suitable for mammalian cell expression was obtained from the pLXIN retroviral vector by PCR. The ORF-438 and IRES DNA fragments were inserted into the pLtyrSN vector to obtain the tyrosinase-expression retroviral vector pLmelSN. The expression vector was amplified in murine PT67 packaging cells, where the ORF-438 and tyrosinase genes were also co-expressed as determined by reverse transcription-PCR. In order to evaluate the vector's ability to restore pigment production in cells with a pigment disorder, albino-mouse skins were histocultured and then infected with the pLmelSN retrovirus. Six days after infection, melanin granules were observed in approximately 60% of albino-mouse hair follicles in the histocultured skin. These results demonstrated that the S. antibioticus mel operon could express an active tyrosinase and produce melanin in the albino-mouse hair follicles. This novel gene therapy approach, using a small and simple tyrosinase operon in a high-expression vector, has a potentially wide application for therapy of pigment disorders in hair follicles.

Albinism↗
PubMed2000

Expression of hepatic thrombopoietin mRNA in primary cultured hepatocytes and in rats with acute liver injury or bone marrow suppression with or without cirrhosis.

BACKGROUND AND AIMS: The main causes of thrombocytopenia in cirrhosis are thought to be platelet destruction and the reduction of thrombopoietin (TPO) expression in the liver. The mechanisms by which levels of TPO mRNA are regulated in cirrhosis have not been elucidated. In this study, we investigated some possible mechanisms. METHODS: We used three experimental models: bone marrow suppression, acute liver injury and primary cultured hepatocytes. We used northern blots to assess the kinetics of TPO mRNA expression in the livers of irradiated rats (with and without cirrhosis) in acute liver injury and in primary cultured hepatocytes treated with hepatotoxin or cytokines. RESULTS: Although the bone marrow was hypocellular, there was no apparent enhancement of TPO mRNA expression in the irradiated rats with cirrhotic livers compared with the unirradiated rats with cirrhotic livers. There were no conspicuous changes in hepatic TPO mRNA expression between the livers of the control rats and the three models of acute liver injury. There were no conspicuous changes in the levels of TPO mRNA between control hepatocytes and hepatocytes treated with hepatotoxin or cytokines. CONCLUSIONS: Our results suggest that bone marrow is not a regulator of hepatic TPO production in cirrhosis. The reduced TPO mRNA expression found in cirrhotic rats may not result merely from serious cellular damage; it may be associated with cirrhosis-specific regulatory mechanisms for the expression of the TPO gene. Further studies are needed to search for other factors that may induce reduced TPO expression.

Acute Disease↗
PubMed2000

Interaction between hyaluronan and CD44 in the development of dimethylnitrosamine-induced liver cirrhosis.

BACKGROUND: A significant increase in serum hyaluronan (HA) levels has been reported in patients with liver cirrhosis. This mechanism is not yet clear, and receptors for HA have not been characterized. In this study, we examined the expression of both HA and its receptors, CD44 and intercellular adhesion molecule-1 (ICAM-1), in dimethylnitrosamine-induced liver cirrhosis. METHODS AND RESULTS: Using biotinylated HA binding protein, HA was detected in the area of periportal fibrosis and around the sinusoidal wall where hepatic fibrosis was developing. Electron microscopy revealed that HA was localized on Ito cells and sinusoidal endothelial cells (SEC). Conversely, CD44, which was only expressed weakly in normal liver, was present in large amounts in cirrhotic liver. The distribution pattern of CD44 was similar to that of HA, however, CD44 was mainly localized on the infiltrating lymphocytes and Kupffer cells. Moreover, CD44 was detected on part of factor VIII-positive SEC. Intercellular adhesion molecule-1, another receptor for HA, was detected on the surface of hepatocytes and around the sinusoidal wall in cirrhotic liver, but its distribution was not accompanied by expression of HA. With respect to CD44 isoforms, the standard form m-RNA predominated in both normal and cirrhotic liver. Variant pMeta-1 mRNA was detected at low levels. CONCLUSIONS: An interaction between HA and CD44 may play a role in the recruitment of numerous infiltrating cells and HA accumulation in hepatic sinusoids. Together with phenotypic changes in the SEC, these results may lead to a disturbance in the elimination of HA during the progression of liver cirrhosis.

Animals↗
PubMed2000

Long-term effect of antihypertensive therapy with calcium antagonist or angiotensin converting enzyme inhibitor on serum nitrite/nitrate levels in human essential hypertension.

Endothelial function is impaired in hypertension. In the present study the effects of long-term antihypertensive therapy on endothelial production of nitric oxide (NO) were investigated. Fifteen untreated mild to moderate essential hypertensive patients and 13 normotensive subjects were enrolled in this study. Blood pressure, heart rate, lipid profiles, cyclic guanosine 3', 5'-monophosphate (cGMP) and nitrite/nitrate (NOx), which are stable metabolites of NO, were measured. The hypertensive patients were treated with a calcium antagonist, benidipine (CAS 91559-74-5) (Ca group: n = 8) or an angiotensin converting enzyme inhibitor, trandolapril (CAS 87679-37-6) (ACEI group: n = 7) and 12 weeks after the treatment the same examinations were performed. NOx and cGMP levels in hypertensive patients were significantly lower than those in normotensive subjects (32.3 +/- 4.1 versus 49.0 +/- 6.5 mumol/l and 2.16 +/- 0.39 versus 3.39 +/- 0.42 pmol/ml, respectively). Both antihypertensive agents decreased the elevated blood pressure (mean blood pressure; 120 +/- 3 to 99 +/- 3 mmHg in Ca group and 117 +/- 4 to 104 +/- 4 mmHg in ACEI group) and normalized the decreased NOx and cGMP levels (29.1 +/- 6.2 to 46.2 +/- 8.6 mumol/l and 1.96 +/- 0.37 to 3.20 +/- 0.71 pmol/ml in Ca group, 36.0 +/- 5.3 to 54.7 +/- 6.9 mumol/l and 2.45 +/- 0.52 to 2.87 +/- 0.43 pmol/ml in ACEI group, respectively). Either benidipine or trandolapril improves the endothelial function and increases the impaired basal release of NO in hypertension. This suggests the beneficial effects of the drugs on protection against the vascular complications in hypertension.

Adult↗
PubMed2000

Endoscopic sphincterotomy for bile duct stones in patients 90 years of age and older.

BACKGROUND: Little information is available on the outcomes of endoscopic sphincterotomy for choledocholithiasis in patients of advanced age (>/=90 years). METHODS: Endoscopic sphincterotomy was performed for choledocholithiasis in 22 patients aged 90 years or more (group A) and 381 aged 70 to 89 years (group B). Clinical features and early outcomes of endoscopic sphincterotomy were compared between the two groups. In group A, long-term results for a mean follow-up period of 33 months were assessed. RESULTS: Group A patients had a higher incidence of symptoms, acute cholangitis and concomitant diseases, as well as larger and more numerous gallstones than did group B patients. Endoscopic sphincterotomy was technically successful in 100% of group A patients and 98% of group B patients. The rate of early complications was low in both groups: 5% in group A and 7% in group B. No deaths related to endoscopic retrograde cholangiopancreatography occurred in group A patients. Complete stone clearance was achieved in 86% of group A patients and 95% of group B patients. Group A required an emergency procedure, general anesthesia, multiple sessions, mechanical lithotripsy, and permanent biliary stent placement more frequently than group B. Late complications occurred in 5% of group A patients. CONCLUSION: Endoscopic sphincterotomy is safe and effective for the treatment of choledocholithiasis in patients 90 years of age or older. Biliary stent placement is a reasonable alternative treatment when stones prove to be difficult to extract.

Age Factors↗
PubMed2000

Mapping of epitopes and structural analysis of antigenic sites in the nucleoprotein of rabies virus.

Linear epitopes on the rabies virus nucleoprotein (N) recognized by six MAbs raised against antigenic sites I (MAbs 6-4, 12-2 and 13-27) and IV (MAbs 6-9, 7-12 and 8-1) were investigated. Based on our previous studies on sites I and IV, 24 consecutively overlapping octapeptides and N- and C-terminal-deleted mutant N proteins were prepared. Results showed that all three site I epitopes studied and two site IV epitopes (for MAbs 8-1 and 6-9) mapped to aa 358-367, and that the other site IV epitope of MAb 7-12 mapped to aa 375-383. Tests using chimeric and truncated proteins showed that MAb 8-1 also requires the N-terminal sequence of the N protein to recognize its binding region more efficiently. Immunofluorescence studies demonstrated that all three site I-specific MAbs and one site IV-specific MAb (7-12) stained the N antigen that was diffusely distributed in the whole cytoplasm; the other two site IV-specific MAbs (6-9 and 8-1) detected only the N antigen in the cytoplasmic inclusion bodies (CIB). An antigenic site II-specific MAb (6-17) also detected CIB-associated N antigen alone. Furthermore, the level of diffuse N antigens decreased after treatment of infected cells with cycloheximide. These results suggest that epitopes at site I are expressed on the immature form of the N protein, but epitope structures of site IV MAbs 6-9 and 8-1 are created and/or exposed only after maturation of the N protein.

Amino Acid Sequence↗
PubMed2000

Application of a reverse transcription-PCR for identification and differentiation of Aichi virus, a new member of the Picornavirus family associated with gastroenteritis in humans.

Aichi viruses isolated in Vero cells from seven patients in five gastroenteritis outbreaks in Japan, five Japanese returning from Southeast Asian countries, and five local children in Pakistan with gastroenteritis were examined for differentiation based on their reactivities with a monoclonal antibody to a standard strain (A846/88) and a reverse transcription-PCR (RT-PCR) of three genomic regions. The RNA sequences were determined for 519 bases of these 17 isolates at the putative junction between the C terminus of 3C and the N terminus of 3D. The analyses revealed an approximately 90% homology between these isolates, which were then divided into two groups: group 1 (genotype A) included six isolates from four outbreaks and one isolate from a traveler and group 2 (genotype B) included one isolate from the other outbreak, four isolates from returning travelers, and all of the isolates from the Pakistani children. Based on the isolate sequences, a primer pair and a biotin-labeled probe were designed for amplification and detection of 223 bases at the 3C-3D junction of Aichi virus RNA in fecal specimens. The Aichi virus RNA was detected in 54 (55%) of 99 fecal specimens from the patients in 12 (32%) of 37 outbreaks of gastroenteritis in Japan. Of the 12 outbreaks, 11 were suspected to be due to genotype A. These results indicated that RT-PCR can be a useful tool to detect Aichi virus in stool samples and that a sequence analysis of PCR products can be employed to identify the prevalent strain in each incident.

Adult↗
PubMed2000

Endoscopic ultrasonography for differential diagnosis of polypoid gall bladder lesions: analysis in surgical and follow up series.

BACKGROUND: Differential diagnosis is often difficult for small (</=20 mm) polypoid lesions of the gall bladder. AIM: To assess the diagnostic accuracy of endoscopic ultrasonography (EUS) for polypoid lesions in a surgical and follow up series. METHODS: A total of 194 patients with small polypoid lesions underwent both ultrasonography and EUS. A tiny echogenic spot or an aggregation of echogenic spots and multiple microcysts or a comet tail artefact indicated cholesterol polyp and adenomyomatosis respectively. Other lesions were diagnosed as neoplastic (adenoma or adenocarcinoma). In the 58 patients who underwent surgery, the histological diagnoses were cholesterol polyp (n = 36), adenomyomatosis (n = 7), adenoma (n = 4), and adenocarcinoma (n = 11). Of the remaining 136 patients with an EUS diagnosis of non-neoplastic lesions, 125 were followed up with ultrasonography alone or with EUS for 1-8.7 years (mean 2.6 years). RESULTS: In the surgical series, EUS (97%) differentiated polypoid lesions more precisely than ultrasonography (76%). During follow up, the lesions remained unchanged in size in 109 (87%) of the 125 patients with non-neoplastic lesions diagnosed by EUS. No neoplastic lesions developed in these patients. Ultrasonography had shown lesions to be neoplastic in 13% of the follow up series. CONCLUSIONS: EUS is highly accurate for differentially diagnosing polypoid gall bladder lesions. It is recommended when ultrasonography cannot rule out neoplastic lesions. Non-neoplastic lesions diagnosed by EUS may be followed and observed with ultrasonography.

Adenocarcinoma↗
PubMed2000

Incremental active learning for optimal generalization.

The problem of designing input signals for optimal generalization is called active learning. In this article, we give a two-stage sampling scheme for reducing both the bias and variance, and based on this scheme, we propose two active learning methods. One is the multipoint search method applicable to arbitrary models. The effectiveness of this method is shown through computer simulations. The other is the optimal sampling method in trigonometric polynomial models. This method precisely specifies the optimal sampling locations.

Algorithms↗
PubMed2000

A case of progressive systemic sclerosis complicated by massive pleural effusion with elevated CA125.

A tumor marker, CA125, is known to increase in the serum or other body fluids in various malignancies such as ovarian cancer. Here we present a case of progressive systemic sclerosis (PSS) with massive pleural effusion, in which CA125 in the serum and pleural fluid were elevated. The serum level of CA125 decreased in accordance with the change of the pleural effusion. CA125 level may be an indicator for the activity of serositis in some cases with collagen vascular diseases.

CA-125 Antigen↗
PubMed2000

Cytological characterization of a pituitary folliculo-stellate-like cell line, Tpit/F1, with special reference to adenosine triphosphate-mediated neuronal nitric oxide synthase expression and nitric oxide secretion.

An immortal nonhormone-producing cell line with a characteristic star-shaped morphology, named Tpit/F1, was derived from an anterior pituitary gland of a temperature-sensitive large T antigen transgenic mouse. To characterize Tpit/F1 cells, we performed cytological studies, which revealed that Tpit/F1 cells express the messenger RNAs of neruonal nitric oxide (NO) synthase, S-100 protein, basic fibroblast growth factor, and pituitary-restricted transcription factor. The Tpit/F1 cells response to pituitary adenylate cyclase-activating peptide comprised the stimulated secretion of interleukin-6. Furthermore, glucocorticoids stimulate glutamine synthase production by Tpit/F1 cells. Considering these cytological characteristics together with their morphology, we deduced that Tpit/F1 cells are derived from pituitary folliculo-stellate (FS) cells. Our cytophysiological analyses of Tpit/F1 cells revealed that intracellular Ca2+ increased dose dependently on ATP administration (0-100 microM), and that this effect did not require the presence of extracellular Ca2+ and was not abolished by treatment with gadolinium, a Ca2+ channel blocker. The ATP-induced increase in intracellular Ca2+ ([Ca2+]i) was completely abolished by treatment with the Ca2+-adenosine triphosphatase (Ca2+-ATPase) inhibitor thapsigargin, which suggests that ATP increases [Ca2+]i by mobilizing internally stored Ca2+ followed by an influx of Ca2+. Moreover, UTP was equipotent with ATP in causing the [Ca2+]i increase in Tpit/F1 cells. Also, the Ca2+ response was prevented by the phospholipase C inhibitor, U-73122, but not by its inactive analog, U-73343. From these results we therefore concluded that ATP acts on Tpit/F1 cells via P2Y2-purinoceptors. Interestingly, both neuronal nitric oxide synthase messenger RNA and NO secretion were increased by ATP administration (10 and 100 microM). These results suggest the biological significance of the topological colocalization of FS cells and endocrine cells. Namely, ATP is cosecreted with hormones from endocrine cells and stimulates NO production by FS cells, and the released NO may regulate neighboring endocrine cell and blood vessels.

Adenosine Triphosphate↗
PubMed2000

A series of novel mutants of Arabidopsis thaliana that are defective in the formation of continuous vascular network: calling the auxin signal flow canalization hypothesis into question.

For the genetic analysis of molecular mechanisms underlying temporal and spatial regulation of vascular pattern formation, we isolated mutants of Arabidopsis thaliana that are impaired in vascular patterning. Microscopic examination of the cotyledonary venation of 3,400 M(3) lines led to the identification of 12 mutant lines. Genetic analysis of 8 of these mutant lines indicated that vein pattern formation in these lines resulted from monogenic recessive mutations in 7 different genes, designated VAN1 through VAN7. Mutations in VAN1 through VAN6 genes caused fragmentation (disconnection or partial loss) of lateral veins of the cotyledon and tertiary veins of the rosette leaf whereas they were less injurious to the formation of major veins. Detailed characterization of the van3 mutant using pAthb8::GUS and pTED3::GUS, as molecular markers for the early stage of vascular tissue formation showed that the provascular tissue of the cotyledonary lateral veins was differentiated in fragments during late embryogenesis. These phenotypes of the van mutants are discussed in relation to the auxin signal flow canalization hypothesis and the diffusion-reaction prepattern hypothesis, with the fragility of the continuity in the minor vein formation favoring the latter hypothesis.

Arabidopsis↗
PubMed2000

The value of plain radiographs in the prediction of outcome in pelvic fractures treated with embolisation therapy.

40 haemodynamically unstable patients with pelvic injuries were studied to assess the ability of plain radiographs to detect haemorrhagic sites. Pelvic radiographs and bilateral angiograms were reviewed separately for detection of haemorrhagic sites in both anterior and posterior segments. Sensitivity and specificity of pelvic radiographs for the detection of haemorrhagic sites were obtained by analysis of angiographic findings. Angiography demonstrated arterial injury in 106 divisions: 26 right anterior, 22 right posterior, 33 left anterior and 25 left posterior. Sensitivities of the radiographs for predicting haemorrhagic sites were higher in the anterior segment (right, 96%; left, 100%) than in the posterior segment (right, 73%; left, 83%). However, specificities were lower in the anterior segment (right, 79%; left, 78%) than in the posterior segment (right, 100%; left, 100%). In 15 (58%) of 26 patients with in-dwelling Foley catheters, including those with catheter deviation, the severity of anterior injury indicated on plain radiographs was correlated with angiographic findings. Plain radiographs of the pelvis proved useful for predicting haemorrhagic sites in haemodynamically unstable patients with pelvic fractures, especially in those with anterior fractures.

Adolescent↗