Biomedical subjects

T Terada

Publications and source records attributed to T Terada.

At least 73 records · Page 4Linked to original sources

PubMed2000

Structural requirements for determining the substrate affinity of peptide transporters PEPT1 and PEPT2.

Peptide transporters PEPT1 and PEPT2 transport numerous compounds including small peptides, peptide-like drugs and nonpeptidic compounds such as valacyclovir. PEPT1 and PEPT2 show low and high affinity for most substrates, respectively, but beta-lactam antibiotics without an alpha-amino group are the only known substrates that prefer PEPT1 to PEPT2. The aim of this study was to compare the recognition and affinity of various substrates between rat PEPT1 and rat PEPT2, and to determine the structural requirements influencing the substrate affinity. [14C]Glycylsarcosine uptake by PEPT1- or PEPT2-expressing transfectant was inhibited by di- and tripeptides, but not by amino acids, tetrapeptides or most cyclic dipeptides. All dipeptides and tripeptides examined showed more potent inhibition of [14C]glycylsarcosine uptake via PEPT2 than via PEPT1, irrespective of their charge and structure. Modification of the alpha-amino group of dipeptides reduced their substrate affinity to both transporters, as compared to unmodified dipeptides, but these dipeptides still showed potent inhibitory effects on PEPT2. Among the nonpeptidic substrates tested, only the eight-amino-octanoic acid displayed stronger inhibition of [14C]glycylsarcosine uptake in PEPT1 than in PEPT2. These findings suggest that alpha- or beta-amino carbonyl function is the key structure responsible for the higher affinity for PEPT2 than for PEPT1.

Animals↗

PubMed2000

Overexpression of MDM2 protein in intrahepatic cholangiocarcinoma: relationship with p53 overexpression, Ki-67 labeling, and clinicopathological features.

Aberration of the p53 gene is thought to be the most frequent genetic alteration in human cancers. Tp53 protein may be inactivated by the binding of the MDM2 protein. MDM2, the product of the mdm2 gene, is an oncoprotein that binds to Tp53 and inhibits the p53-mediated transactivation. MDM2 overexpression has been reported in several human cancers, but not in intrahepatic cholangiocarcinoma (ICC). Therefore, we have evaluated the immunohistochemical overexpression of MDM2 and the relationship between its expression and histological grade, clinicopathological features, Tp53 overexpression, and Ki-67 labeling index in 47 cases of ICC. MDM2 and Tp53 were found to be overexpressed in 38% and 57% of the tumor, respectively. MDM2 and Tp53 were not expressed in non-tumorous liver tissue. There was no significant difference between the MDM2 overexpression and ICC tumor grade. However, MDM2 overexpression correlated with the presence of metastases (P<0.01) and advanced tumor stage (P<0.05). MDM2 overexpression also correlated with Tp53 overexpression (P<0.03) and Ki-67 labeling index (P<0.03). Our findings suggest that MDM2 overexpression may play a role in the late stage of human ICC.

Bile Duct Neoplasms↗

PubMed2000

Haemorrhagic complication following percutaneous transluminal angioplasty for carotid stenosis.

We report 2 cases with haemorrhagic complications following percutaneous transluminal angioplasty (PTA) for carotid stenosis. Computed tomography (CT) scanning of these cases demonstrated diffuse subarachnoid haemorrhage in 1 case, and intracerebral haemorrhage in the other case on the next day after PTA. In the latter case, we measured cerebral blood flow velocity and mean transit time with transcranial doppler (TCD) and dynamic CT scan, which demonstrated remarkable increases in the blood flow velocity and peak height, respectively. From these results, postoperative hyperperfusion was suggested to have caused haemorrhagic complications.

Aged↗

PubMed2000

Effects of wortmannin on the kinetics of GVBD and the activities of the maturation-promoting factor and mitogen-activated protein kinase during bovine oocyte maturation in vitro.

The present study was conducted with the objective of examining the effect of wortmanin, a specific PI 3-kinase inhibitor, on the kinetic of GVBD, and on the activities of the maturation-promoting factor (MPF) and mitogen-activated protein (MAP) kinase during bovine oocyte maturation. The time sequence for GVBD was not different between oocytes cultured with or without wortmannin. Most of the cultured oocytes were at the filamentous bivalents stage after 4 h of culture. Six hours after the start of culture, most of the oocytes possessed germinal vesicles with condensed bivalent, and by 10 h of culture nearly all of the cultured oocytes underwent GVBD. A gradual increase in MPF activity until 12 h of culture was observed in the presence and absence of wortmannin. A sharp decrease in MPF activity in oocytes cultured without wortmannin treatment was recorded at 14 h of culture. Thereafter, MPF regained activity, reaching a maximum level at 20 to 24 h of culture. For oocytes cultured with wortmannin, no decline in the activity of MPF was observed during the interval from 12 to 24 h of culture. For these oocytes the MPF activity remained nearly stable during this transition until the end of incubation. The presence of wortmannin in the maturation medium did not alter MAP kinase activity. Taken together, these observations indicate that inhibition of PI 3-kinase does not modulate the time sequence of GVBD or the pattern of MAP kinase activity in bovine oocytes. However, PI 3-kinase might be one of the molecules that regulate the sharp reduction in the activity of MPF during the MI/MII transition.

Androstadienes↗

PubMed2000

Increased mast cells in hepatocellular carcinoma and intrahepatic cholangiocarcinoma.

BACKGROUND/AIMS: Human mast cells are categorized into those positive only for tryptase (MC(T)) and those positive for both tryptase and chymase (MC(TC)). METHODS: We investigated mast cells in "normal" livers (n=13), hepatocellular carcinoma (HCC) (n= 49) and intrahepatic cholangiocarcinoma (ICC) (n= 44) by double immunostaining and quantitative morphometry. RESULTS: In "normal" livers, mast cells were located in portal tracts, and to a lesser extent in the sinusoids. In HCC, mast cells were noted in tumoral sinusoids and fibrous septa. In ICC, many mast cells were present in tumoral stroma. Morphometry showed that densities of mast cells in HCC and ICC were significantly higher than those in "normal" livers. The density of mast cells in ICC (57.6+/-62.4/mm2) was significantly higher than that in HCC (9.32+/-12.9/mm2). The density of sinusoidal mast cells was significantly higher in HCC (1.79+/-2.35/mm2) than in "normal" livers (0.13+/-0.07/mm2). The density of stromal mast cells was significantly higher in ICC (57.6+/-62.4/mm2) than that of portal tracts in "normal" livers (28.4+/-7.0/mm2). MC(T) and MC(TC) were approximately 20% and 80%, respectively, being consistent in any anatomical compartments. CONCLUSIONS: Mast cells increase during carcinogenesis in HCC and ICC, and they may play a role in fibrosis or tumor immunology in HCC and ICC.

Adult↗

PubMed2000

Protein expression of CD44 (standard and variant isoforms) in hepatocellular carcinoma: relationships with tumor grade, clinicopathologic parameters, p53 expression, and patient survival.

BACKGROUND/AIMS: Members of the CD44 family are transmembrane glycoproteins which act mainly as receptors for hyaluronan. We have examined the expression of CD44s and several CD44v and the relationship between these and hepatocellular carcinoma (HCC) grade, clinicopathological parameters, p53 expression, and patient survival in HCC. METHODS: Formalin-fixed, paraffin-embedded tissue sections from 107 surgically resected HCC were examined immunohistochemically using a semi-quantitative scoring system to detect the expression of different forms of CD44. RESULTS: The number of CD44s-positive cases was 36 (34%), CD44v5 52 (49%), CD44v6 29 (27%), CD44v7-8 41 (38%), and CD44v10 26 (24%). Expression of these molecules correlated with high histological grade, being the highest in poorly-differentiated HCC. High CD44v6 expression significantly correlated with the presence of vascular invasion and p53 overexpression. Kaplan-Meier examination of patient survival revealed that HCC patients with positivity of each of these five molecules had a reduced survival rate, and that HCC patients positive for all the five CD44 molecules had worse survival than HCC patients positive for four or less of these CD44 molecules. In multivariate survival analysis, CD44s positivity was an independent factor. However, positivity for one or more CD44 isoforms was the most useful independent factor for overall survival. CONCLUSION: These results suggest that up-regulation of CD44 isoforms is associated with poorly-differentiated HCC and shortened survival.

Adolescent↗

PubMed2000

Characterization of two mu class glutathione S-transferases from guinea pig lens.

Glutathione S-transferase (GST) plays an important role in the detoxifications of foreign electrophiles. Two GSTs of class mu from guinea pig lens were purified with Sephacryl S-100 gelfiltration, S-Hexyl glutathione Agarose affinity and Q-Sepharose anion exchange chromatographies. These GSTs (GST-A and B) showed similar relative molecular masses of 22.9 and 22.5 kDa, respectively. Two protein bands which crossreacted with anti GSTYb1 (GST 3-3) were detected in lens cytosolic crude extract on Western blotting and they showed Mrs corresponding to the purified enzymes. These GSTs showed a strong resistance against H2O2, 1,2-naphthoquinone and superoxide anion consistent with the other GSTs in class mu from animal tissues.

Animals↗

PubMed2000

N-terminal halves of rat H+/peptide transporters are responsible for their substrate recognition.

PURPOSE: Peptide transporters PEPT1 and PEPT2 differ substantially in their substrate affinity and recognition. The aim of this study is to define the structural domains which influence the functional characteristics of both transporters METHODS: Two kinds of chimeric peptide transporters (PEPT-N1C2 and PEPT-N2C1) were constructed, and their functional characteristics were compared with those of wild-type transporters in stable transfectants. RESULTS: PEPT-N1C2, the N-terminal half of rat PEPT1 and the C-terminal half of rat PEPT2, and the reciprocal chimera PEPT-N2C1 were functionally expressed in LLC-PK1 cells. The pH-profiles of [14C] glycylsarcosine uptake by PEPT-N1C2 and PEPT-N2C1 were close to those of PEPT1 and PEPT2, respectively. Substrate recognition for PEPT-N1C2 and PEPT-N2C1 was also similar to that of PEPT1 and PEPT2, respectively. However, substrate affinities for PEPT-N1C2 were higher than those for PEPT1, although those for PEPT-N2C1 and PEPT2 were comparable. CONCLUSIONS: These results indicate that functional regions which are associated with the extracellular pH changes and are responsible for substrate recognition of PEPT1 and PEPT2 may be located in the N-terminal halves of the proteins. In addition, it is suggested that the domain to affect the substrate affinity exists in the C-terminal as well as in the N-terminal half of rat PEPT2.

Animals↗

PubMed2000

Mast cell subpopulations in chronic inflammatory hepatobiliary diseases.

AIM/BACKGROUND: In various hepatobiliary diseases mast cells have been found to be associated with fibrogenesis. However, mast cell subpopulations have not been investigated in the human liver in normal subjects or in disease. Human mast cells are categorized into mast cells positive for tryptase (MC(T)) only and mast cells positive for both tryptase and chymase (MC(TC)). METHODS: In this study we investigated mast cell subpopulations (MC(T) and MC(TC)) by double immunostaining for mast cell tryptase and chymase as well as by a computer-aided quantitative morphometry in 13 normal livers and in 193 liver tissue specimens comprising of primary biliary cirrhosis (n=43), autoimmune hepatitis (n=11), chronic hepatitis B (n=37), chronic hepatitis C (n=41), alcoholic liver disease (n=40) and hepatolithiasis (n=21). RESULTS: The densities of MC(T) and MC(TC) per 1 mm2 stroma were low in normal livers but high in chronic liver diseases, and correlated positively with the degree of fibrosis. The percentages of MC(T) and MC(TC) subpopulations were 25% and 75%, respectively. The percentage was almost the same in normal livers and various hepatobliliary diseases, as well as between less fibrotic cases and more fibrotic cases in liver diseases. CONCLUSIONS: These results suggest that MC(T) and MC(TC) subpopulations in healthy and diseased livers do not change during liver fibrosis of any etiology.

Adolescent↗

PubMed2000

Protein expression of MDM2 and its clinicopathological relationships in human hepatocellular carcinoma.

BACKGROUND/AIMS: The transcription of mdm2 gene is activated by p53 and this limits the growth-suppressing activity of p53 by direct binding. It has been reported that MDM2 protein is overexpressed in several types of cancers. However, there have been no immunohistochemical studies on MDM2 in human hepatocellular carcinoma (HCC). METHODS: We immunohistochemically examined the expression of MDM2 and the relationships between its expression and histological grade, clinicopathological parameters, p53 expression and patient survival in 107 patients with HCC. RESULTS: The frequency of MDM2 positivity in the nuclei of HCC cells was 28/107 (26%). There was no correlation between the MDM2 expression and HCC grade. However, positivity of MDM2 expression significantly correlated with small HCC size (p<0.05, chi2 test) and the absence of vascular invasion (p<0.01, chi2 test). No significant differences were noted between MDM2 expression and capsular invasion or satellite nodules. Expression of MDM2 showed a significantly positive correlation with expression of p53 (p<0.03, chi2 test). Patients with positive expression of MDM2 had poorer prognosis than patients with negative MDM2 expression. MDM2 expression was the most useful independent factor for overall survival (p=0.0001). CONCLUSIONS: MDM2 was expressed in 26% of HCC, and its expression correlated positively with p53 mutations. MDM2 over-expression is a useful predictor of poor prognosis in patients with HCC following hepatic resection.

Adolescent↗

PubMed2000

Increased midkine expression in intrahepatic cholangiocarcinoma: immunohistochemical and in situ hybridization analyses.

AIMS/BACKGROUND: Midkine (MK) is a novel heparin-binding growth factor whose gene was identified in embryonal carcinoma cells in the early stages of retinoic acid-induced differentiation. This study investigates the overexpression of MK in intrahepatic cholangiocarcinoma (CC). METHODS: Forty-five primary CC specimens from patients (aged 19-81 years, 24 males and 21 females) were examined. Histologically, 17 cases of CC were classified as the well-differentiated type, 19 as moderately-differentiated and 9 as poorly-differentiated. Immunohistochemical analysis was performed using a rat IgG2a monoclonal antibody against the carboxyl terminal region of human MK. RESULTS: We successfully applied this monoclonal antibody against MK to analyze archival paraffin sections. The cancer tissues showed a positive reaction to this antibody, and there was an intense reaction in their cytoplasm. Approximately 40% of individuals with CC (17/45) had tumor cells that expressed MK, and these were classified into the following types: moderately-differentiated type (9/19), well-differentiated type (8/17) and poorly-differentiated type (0/ 9). In situ hybridization analysis revealed that signals of MK transcripts were found in the cytoplasm of the cancer cells; the distribution and localization of the MK-transcript signals determined by in situ hybridization analysis were similar to those obtained by immunohistochemical analysis. CONCLUSIONS: These findings revealed that CC express increased MK at the messenger RNA and protein levels.

Adult↗

PubMed2000

Protein expression of double-stranded RNA-activated protein kinase (PKR) in intrahepatic bile ducts in normal adult livers, fetal livers, primary biliary cirrhosis, hepatolithiasis and intrahepatic cholangiocarcinoma.

BACKGROUND/AIM: The protein expression of double-stranded RNA-activated protein kinase (PKR) in intrahepatic bile ducts has not been investigated. METHODS: Immunohistochemistry and a semiquantitative scoring method in normal liver and biliary diseases were used for the investigation. RESULTS: In "normal" adult livers (n=10), intrahepatic bile ducts were negative for PKR. In normal fetal livers (n=25), primitive biliary epithelia were almost negative for PKR. In primary biliary cirrhosis (PBC) (n=30), damaged bile ducts were frequently positive for PKR, while uninvolved bile ducts were negative. In hepatolithiasis (n=27), proliferated bile ducts were positive for PKR, and the PKR score correlated with the degree of proliferation. In cholangiocarcinoma (CC) (n=44), PKR expression was frequently noted, and the PKR score correlated with good differentiation of CC, being highest in well-differentiated CC and lowest in poorly-differentiated CC. The PKR score decreased in the following order: CC (mean PKR score=3.96), hepatolithiasis (2.56), PBC (1.60), normal fetal liver (0.40), and normal adult livers (0.00). The PKR expression in hepatocytes was "baseline" in normal adult livers, while moderately increased in fetal livers, PBC, hepatolithiasis and CC. CONCLUSIONS: Although the significance of these data is unclear, they suggest (i) that PKR is absent in bile ducts in normal adult and fetal livers, (ii) that PKR in bile duct cells newly emerges or increases in PBC, hepatolithiasis, and CC, (iii) that PKR accumulates in damaged bile ducts in PBC, (iv) that PKR increases in parallel with biliary cell proliferation in hepatolithiasis, and (v) that PKR expression correlates with differentiation in CC. PKR expression in intrahepatic bile ducts seems to be associated with inflammation or cell proliferation of the bile duct cells.

Bile Duct Neoplasms↗

PubMed2000

Divergent expression of midkine in the human fetal liver and kidney: immunohistochemical analysis of developmental changes in hilar primitive bile ducts and hepatocytes.

BACKGROUND/AIMS: Midkine (MK) is a novel heparin-binding growth factor whose gene has been identified in embryonal carcinoma cells in early stages of retinoic acid-induced differentiation. In this study, we investigated the developmental expression of MK protein in the human fetal liver and kidney. METHODS: Twenty-one specimens each of the liver and kidney from fetuses (gestational weeks from 9 to 40) and neonates less than 4 weeks old were examined. Immunohistochemical and Western blot analyses were performed using a rat IgG2a monoclonal antibody against the carboxyl terminal region of human MK. RESULTS: Immunohistochemical analysis revealed MK expression in the human fetal liver and kidney. The MK expression in the fetal liver showed a strong reaction from 9 to 16 gestational weeks. MK was expressed in the ductal plate, migrating biliary cells and newly formed bile ducts, and in hepatocytes of the hilar region in all specimens in the first and second trimesters. By contrast, the MK expression decreased gradually and was weak or not detected in the third trimester and neonatal period. However, MK expression in the kidney was found at 16 gestational weeks, as well as during both gestation and the neonatal period. CONCLUSIONS: Divergent MK-expression was detected in the human fetal liver and kidney, and its expression may be related to fetal development, maturation, and functions of the liver and kidney.

Bile Ducts, Intrahepatic↗

PubMed2000

Structural genomics projects in Japan.

Two major structural genomics projects exist in Japan. The oldest, the RIKEN Structural Genomics Initiative, has two major goals: to determine bacterial, mammalian, and plant protein structures by X-ray crystallography and NMR spectroscopy and to perform functional analyses with the target proteins. The newest, the structural genomics project at the Biological Information Research Center, focuses on human membrane proteins.

Animals↗

PubMed2000

Immunohistochemical and in situ hybridization analyses of midkine expression in thyroid papillary carcinoma.

Midkine (MK) is a novel heparin-binding growth factor whose gene has been identified in embryonal carcinoma cells in early stages of retinoic acid-induced differentiation. We immunohistochemically examined 90 thyroid papillary carcinomas (85 invasive type and five encapsulated type), using a rat IgG2a monoclonal antibody against the carboxyl terminal region of human MK in archival paraffin sections. The thyroid tumors exhibited an intense reaction in the cytoplasm. Most of the papillary carcinomas (77/90), had tumor cells that expressed MK. These were classified into the following two types: invasive type (76/85) and encapsulated type (1/5). Notably, the intensity of MK was stronger at the invading border area of the tumors than in the center. In tissues adjacent to the cancer tissues, normal follicular epithelial cells expressed MK very faintly or not at all. The in situ hybridization analysis revealed that the signals of MK transcripts were found in the cytoplasm of the cancer cells. In the noncancerous follicular epithelial cells adjacent to neoplasm the signals of MK transcripts were detected very weakly or not at all. The distribution and localization of the MK-transcript signals determined by in situ hybridization analysis were similar to those obtained by immunohistochemical analysis. We conclude that thyroid papillary carcinoma strongly expresses MK protein and messenger RNA, and that this overexpression may relate to the development and invasion of these carcinomas.

Adult↗

PubMed2000

Cloning and bacterial expression of monomeric short-chain dehydrogenase/reductase (carbonyl reductase) from CHO-K1 cells.

Mammalian carbonyl reductase (EC 1.1.1.184) is an enzyme that can catalyze the reduction of many carbonyl compounds, using NAD(P)H. We isolated a cDNA of carbonyl reductase (CHO-CR) from CHO-K1 cells which was 1208 bp long, including a poly(A) tail, and contained an 831-bp ORF. The deduced amino-acid sequence of 277 residues contained a typical motif for NADP+-binding (TGxxxGxG) and an SDR active site motif (S-Y-K). CHO-CR closely resembles mammalian carbonyl reductases with 71-73% identity. CHO-CR cDNA had the highest similarity to human CBR3 with 86% identity. Using the pET-28a expression vector, recombinant CHO-CR (rCHO-CR) was expressed in Escherichia coli BL21 (DE3) cells and purified with a Ni2+-affinity resin to homogeneity with a 35% yield. rCHO-CR had broad substrate specificity towards xenobiotic carbonyl compounds. RT-PCR of Chinese hamster tissues suggest that CHO-CR is highly expressed in kidney, testis, brain, heart, liver, uterus and ovary. Southern blotting analysis indicated the complexity of the Chinese hamster carbonyl reductase gene.

Alcohol Oxidoreductases↗

PubMed2000

Primary T-cell non-Hodgkin's malignant lymphoma of the appendix.

A case of primary T-cell lymphoma of the appendix in an 84-year-old female was reported. Appendectomy was performed as a result of the clinical diagnosis of acute appendicitis, due to the rebound tenderness of McBurney's point and thickness of the appendix wall as determined from ultra echo sonograph. Grossly, the surgical resected appendix did not have a dominant inflammatory appearance, therefore a tumor was suspected. Microscopic examination showed diffused proliferation of large and medium size lymphoma cells. Immunohistochemical examination further revealed that the lymphoma cells were positive for T-cell markers. To ensure this was a T-cell lymphoma, molecular examination was performed using paraffin-embedded tissue sections, since T-cell lymphoma of the appendix is extremely rare. Polymerase chain reaction (PCR) single-strand conformation polymorphism (SSCP) analysis demonstrated monoclonal T-cell receptor gene rearrangement. T-cell-rich B-cell lymphoma was excluded. To our knowledge, this is the first reported case of primary T-cell lymphoma of the appendix. PCR-SSCP analysis in paraffin-embedded tissue section was very useful in the diagnosis of lymphoma cell monoclonality.

Aged↗

PubMed2000

Inhibitory effects of antisense oligonucleotides on the expression of procollagen type III gene in mouse hepatic stellate cells transformed by simian virus 40.

The effects of phosphorothioate antisense oligonucleotides (ASO), complementary to the AUG start region, the junctional region of the intron and exon, and to exon of the procollagen type III gene, were investigated in a mouse hepatic stellate cell (HSC) line transformed by the simian virus 40 gene, SV68c-IS cells. ASO were transfected by lipofection. Immunohistochemistry, western and northern blotting showed inhibitory effects on procollagen type III gene expression by ASO that were complementary to the AUG start region and the junctional region of the intron and exon 2. However, ASO complementary to the exon 2 and 3, junctional region of the intron and exon 3, and sense oligonucleotides complementary to each ASO did not show any inhibitory effects. The effects of ASO complementary to the AUG start region were greater than those of ASO complementary to the junctional region. The effects of ASO were transient and a large amount of ASO was required to induce inhibitory effects without lipofection. ASO were effective in inhibiting the expression of the procollagen type III gene in the HSC which is well known to play a critical role in liver fibrosis.

Actins↗