Sensitivity and specificity of the APC resistance assay in detection of individuals with factor V(Leiden)
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Blood Coagulation Tests↗
Biomedical subjects
T Shen
Publications and source records attributed to T Shen.
Changes in the expression of adenylyl cyclases in the rat uterus during the course of pregnancy.
The changes in the expression of the various adenylyl cyclases (ACs) in the rat uterus during the course of pregnancy and after delivery were examined by Northern blot analysis and AC assay. Northern blot analysis revealed that five isoforms of ACs (AC2, AC4, AC6, AC7, and AC9) were expressed in the rat uterus, AC6 being the most abundant. The level of expression of these ACs increased 1.7- to 3.4-fold during the course of pregnancy and diminished near term and after delivery. The highest level of expression in each type of AC was consistently seen on Day 17 of pregnancy, and the relative increase of expression, as compared to that in nonpregnant rats, was as follows: AC2 > AC4 > AC7 > AC9 > AC6. In agreement with these findings, both basal and forskolin-stimulated AC activities exhibited a 2- to 3-fold increase during the course of pregnancy, followed by a decrease near term. Our data indicate that post-receptor events, namely marked changes in the level of AC mRNA (and presumably proteins) occur during pregnancy and after delivery and that they contribute to the essential role of cAMP in maintaining uterus quiescence.
Adenylyl Cyclases↗
Expression of adenylyl cyclase mRNAs in the adult, in developing, and in the Brattleboro rat kidney.
The activity and expression of adenylyl cyclases (AC) were examined in the adult rat renal cortex and medulla. Northern blot analysis and in situ hybridization demonstrated that AC-6 was the predominant isoform in the adult rat kidney, whereas AC-4, -5, and -9 had a lower expression. AC-4 expression was higher in the cortex, and AC-5 and AC-6 were higher in the medulla. AC-9 expression was at the same level in both regions. AC activity was high in the fetus and declined in the adult. At all stages, AC activity was sensitive to parathyroid hormone, whereas no stimulation by vasopressin and isoproterenol was found in the fetus and the neonate. AC-5 and AC-6 mRNAs increased at day 1 and then markedly decreased, paralleling the decline in AC activity. The mRNA of AC-4 did not change and that of AC-9 increased markedly until adult. In the homozygous Brattleboro rat kidney, the expression of all these isoforms was decreased.
Adenylyl Cyclases↗
Localization and differential expression of adenylyl cyclase messenger ribonucleic acids in rat adrenal gland determined by in situ hybridization.
The expression of adenylyl cyclases (ACs) in the adult rat adrenal gland was examined. In situ hybridization revealed specific patterns of AC messenger RNA (mRNA) distribution. AC1 was limited exclusively to the adrenal medulla. AC5 and AC6 were mainly expressed in the adrenal medulla, with a weak expression in the zona glomerulosa. AC9 was found in all the three regions of the adrenal cortex but not in the adrenal medulla. All these ACs were detected on postnatal day 1 (PN1), and their pattern of expression was unchanged on PN7, PN21, and PN90 (adult). We analyzed the response of these ACs to various physiological conditions known to affect the synthesis of aldosterone and corticosterone in the adrenal cortex. Our study demonstrates a specific increase of AC6 but not AC5 mRNA in the zona glomerulosa of rats given a low sodium diet. AC9 mRNA was increased in all the three cortical zones of rats treated with ACTH. We suggest that AC6 and AC9 play important roles in different pathways associated with the regulation of aldosterone and corticosteroid production.
Adenylyl Cyclases↗
[Cloning and expression of the E. coli serine hydroxymethyltransferase gene (glyA)].
The E. coli K12 glyA gene(13 kb), encoding serine hydroxymethyltransferase (SHMT), has been cloned in the plasmid vector pBR329 using insertion inactivation and complementation test. Subcloning of segments of the original insert (13 kb) into plasmids pBR322, pBR329 and pSMY901 established that a 2.6 kb PstI-EcoR fragment carries the glyA gene. The 12 strains of transforments containing recombined plasmid. were obtained. SHMT and glyA gene product level in strains carrying glyA plasmids were different. No SHMT activity was observed in host strains. The glyA gene products for JM109(pSM13), K12(pSM13), K12(pSM14) and K12(pSM15) account for 15.7%, 15.4%, 11.8%, and 9.48% of the total dissoluble cell protein, respectively.
Cloning, Molecular↗
Gallstones and their chemical types in relation to serum lipids and apolipoprotein levels.
OBJECTIVE: To determine the profile of lipidemia in patients with gallstones and the characteristics of lipidemia in different kinds of gallstone in gallbladder for predicting high risk subjects predisposed to gallstone formation by means of some serum parameters. METHODS: Serum lipids and apolipoproteins levels in 47 patients with stone in gallbladder (stone group) were compared with those in 19 inpatients without stone (control group). The characteristics of lipidemia in different kinds of gallbladder stones were also compared. RESULTS: Serum apolipoprotein (Apo) A1, C2 and E levels in the stone group significantly increased as compared with the control group (P < 0.01), but there were no statistically significant differences in TC, TG, LDL-C, HDL-C, HDL-C/TC, LDL-C/HDL-C, Apo A2, B and C3 and Apo A1/Apo B levels between the stone and control groups (P > 0.05). Increased levels of serum LDL-C and Apo B and the LDL-C/HDL-C ratio (P < 0.05) were characterized as an index of cholesterol stones, while elevated levels of serum TG and Apo C2 (P < 0.05) as an index of pigment stones. CONCLUSIONS: Serum apolipoproteins might be more sensitive parameters as compared with serum lipids in distinguishing patients with stones from subjects without stones. There are different profiles of serum lipids and apolipoproteins in different chemical types of gallbladder stones.
Adult↗
Site-directed mutagenesis within an ectoplasmic ATPase consensus sequence abrogates the cell aggregating properties of the rat liver canalicular bile acid transporter/ecto-ATPase/cell CAM 105 and carcinoembryonic antigen.
Recent studies of the rat liver canalicular bile acid transporter/ecto-ATPase/cell CAM 105 (CBATP), a member of the carcinoembryonic antigen (CEA) supergene family, indicate that it is a multifunctional protein possessing bile acid efflux, ecto-ATPase, and intercellular aggregating properties. Cheung et al. (Cheung, P. H., Luo, W., Qiu, Y., Zhang, K. E., Millron, P., Lin, S. H. (1993) J. Biol. Chem. 268, 24303-24310) have shown that the amino-terminal Ig V-like domain of this protein is required for its aggregating properties, much like the homologous amino-terminal domain of CEA is required for its aggregating properties. The amino-terminal domains of both CBATP and CEA include a consensus ATPase sequence. Site-directed mutagenesis within this ATPase consensus sequence completely eliminates the ecto-ATPase activity of CBATP (Sippel, C. J., McCollum, M., Perlmutter, D. H. (1994) J. Biol. Chem. 269, 2820-2826). In this study we examined the possibility that it is this ATPase consensus sequence which is required for the cell aggregating properties of CBATP and CEA and whether there is a relationship between ATPase, aggregating, and bile acid efflux activities. For this we used a baculovirus vector to express in Sf9 cells wild type as well as mutant and chimeric CBATP and CEA molecules. The results indicate that Arg-98 in the ATPase consensus sequence of CBATP and the corresponding residue of CEA are essential for the aggregating properties of these molecules. Moreover Arg-98 is essential for CBATP to interact with itself, CEA to interact with itself, and CBATP to interact with CEA. However, the role of Arg-98 in aggregation is distinct from its role in ecto-ATPase activity and the aggregating properties cannot be attributed to a change in ATP metabolism in the pericellular milieu.
Adenosine Triphosphatases↗
Use of alternative polyadenylation sites in the synthesis of mRNAs encoding the interferon-induced tryptophanyl tRNA synthetase.
The interferon-mediated induction of the gene encoding the human tryptophanyl tRNA synthetase (WRS) results in the production of two mRNA species differing in size by approximately 800 base pairs (bp). Two distinctly sized cDNAs differing by approximately 800 bp were isolated from a cDNA library generated from mRNA prepared from IFN-gamma-treated cells. Northern blot analysis using cDNA probes recognizing different regions of the WRS mRNA reveals distinctly sized mRNAs differing in the length of their 3' untranslated regions. Differential display analysis using oligo dT primers demonstrates that the different sized WRS mRNAs result from alternative polyadenylation of this transcript.
Alternative Splicing↗
Effect of economic reforms on child growth in urban and rural areas of China.
BACKGROUND: Beginning in 1978, China implemented economic reforms to transform the economy to a free-market system. We compared the effect of the reforms on the growth of children in urban and rural areas. METHODS: Using data from five large cross-sectional surveys conducted between 1975 and 1992, we examined the trends in height for age of children two to five years of age in urban and rural areas. Mean height for age was expressed as the height in centimeters adjusted to a reference value of 99.1 cm for a 42-month-old boy. RESULTS: Height increased before and during the economic reforms. In 1975, the average height of children in periurban rural areas was about 3.5 cm less than that of children in urban areas. Between 1975 and 1985, the average height of children in periurban rural areas increased by 2.0 cm, as compared with 1.3 cm in urban children. Between 1987 and 1992, the average height of both urban and rural children increased, but the net increase for rural children was only one fifth that for urban children (0.5 vs. 2.5 cm). In a 1990 survey of seven provinces, the rural mean height was 92.5 cm, as compared with the urban mean of 96.9 cm and the reference value of 99.1 cm; 38 percent of rural children had moderate stunting of growth and 15 percent had severe stunting, as compared with 10 percent and 3 percent of urban children, respectively. Differences in height between rural and urban children were greater in provinces in which the average height of children was lower. CONCLUSIONS: Despite an overall improvement in child growth during the economic reforms in China, the improvement has not been equitable, as judged by increased differences in height between rural and urban children and increased disparities within rural area.
Adolescent↗
Lack of plasminogen activator inhibitor-1 effect in a transgenic mouse model of metastatic melanoma.
Tumor cell invasion and metastasis is a complex, multistep process that is postulated to require degradation of extracellular matrix at several steps. Urokinase-type plasminogen activator (uPA) is expressed on the cell surface of B16 murine melanoma cells and is thought to contribute to the pericellular proteolysis necessary for tumor cell migration. In vitro modification of B16 melanoma cell surface uPA activity has been shown to alter the invasive and metastatic potential of these murine melanoma cells in vivo. Plasminogen activator inhibitor-1 (PAI-1), a rapid inhibitor of both uPA and tissue-type plasminogen activator (tPA) is the major physiologic regulator of plasminogen activator activity. To test the role of host PAI-1 in the invasive and metastatic capacity of B16 melanoma cells we analyzed local tumor growth and pulmonary metastasis in transgenic mice engineered to overexpress murine PAI-1 in multiple tissues including lung, and in mice completely deficient in PAI-1. No significant difference in the number of pulmonary metastases was observed after intravenous inoculation of tumor cells into PAI-1-overexpressing and PAI-1-deficient mice when compared with wild-type controls. Similarly, in a spontaneous metastasis model, PAI-1-overexpressing and PAI-1-deficient mice demonstrated no difference in primary tumor size or overall survival. These data demonstrate that wide variations of host PAI-1 expression, from complete absence to marked overexpression, does not significantly influence the metastatic potential of B16 melanoma cells in a murine model.
Animals↗
Bleomycin-induced pulmonary fibrosis in transgenic mice that either lack or overexpress the murine plasminogen activator inhibitor-1 gene.
Impaired fibrinolytic activity within the lung is a common manifestation of acute and chronic inflammatory lung diseases. Because the fibrinolytic system is active during repair processes that restore injured tissues to normal, reduced fibrinolytic activity may contribute to the subsequent development of pulmonary fibrosis. To examine the relationship between the fibrinolytic system and pulmonary fibrosis, lung inflammation was induced by bleomycin in transgenic mice that either overexpressed or were completely deficient in murine plasminogen activator inhibitor-1 (PAI-1). 2 wk after 0.075 U of bleomycin, the lungs of transgenic mice overexpressing PAI-1 contained significantly more hydroxyproline (118 +/- 8 micrograms) than littermate controls (70.5 +/- 8 micrograms, P < 0.005). 3 wk after administration of a higher dose of bleomycin (0.15 U), the lung hydroxyproline content of mice completely deficient in PAI-1 (49 +/- 8 micrograms) was not significantly different (P = 0.63) than that of control animals receiving saline (37 +/- 1 micrograms), while hydroxyproline content was significantly increased in heterozygote (77 +/- 12 micrograms, P = 0.06) and wild-type (124 +/- 19 micrograms, P < 0.001) littermates. These data demonstrate a direct correlation between the genetically determined level of PAI-1 expression and the extent of collagen accumulation that follows inflammatory lung injury. These results strongly support the hypothesis that alterations in fibrinolytic activity influence the extent of pulmonary fibrosis that occurs after inflammatory injury.
Animals↗
The ability of bile to scavenge superoxide radicals and pigment gallstone formation in guinea pigs.
After partial ligation of the common bile duct (CBD) of guinea pigs, 14 of 16 animals developed pigment gallstones within one week (S group). Intraperitoneal injection of Vit. E and C, each 10 mg/kg daily from 3 days before CBD ligation to one week after the operation (S+V group), decreased the gallstone incidence to 5/14 (exact probability < 0.01). The gallstone incidence in the control group, that only received laparotomy without ligation of the CBD, was 0/15. Biochemical analysis of the gallbladder bile showed that stricture of the CBD was associated with a significant increase in levels of unconjugated bilirubin (UCB) and Ca2+ (p < 0.05 and < 0.01). Simultaneously the scavenging rate (SR) of superoxide radical in bile significantly decreased (p < 0.05). Comparing S+V group with S group, the effect of Vit. E and C on the concentrations of UCB and Ca2+ in bile was not significant (both p > 0.05), but Vit. E and C normalized the SR, and the difference between S group and S+V group was significant (p < 0.05). These results suggested that Vit. E and C, known as antioxidants, enhanced the ability to scavenge oxygen radical in S+V group; and that in addition to the increases of UCB and Ca2+ concentrations, the participation of oxygen radicals might be of importance for pigment gallstone formation induced by bile duct obstruction.
Animals↗
Presence of free radicals in pigment gallstone in vivo.
OBJECTIVE: To clarify whether free radical, which may play a role in pigment gallstone formation, is present in pigment gallstones in vivo. MATERIALS AND METHODS: Free radical signal of gallstones from 18 patients was detected by electron paramagnetic resonance spectroscopy at 77K under anaerobic condition and in air (control). As soon as the anaerobic determination was finished, the fresh anaerobic sample was exposed to air and stored in a freezer at -20 degrees C. RESULTS: Free radical signal (g = 2.0038) was detected in fresh anaerobic samples containing more than 2% bilirubin compound, and the signal intensity correlated linearly with the content of calcium bilirubinate (r = +0.95, P < 0.0005). During the storage at -20 degrees C and exposure to air, the signal intensity of each anaerobic sample and its control increased gradually, eventually reaching the same stable level. Fe(III) signal intensity was enhanced synchronously and related linearly with free radical signal (r = +0.99, P < 0.0005). CONCLUSIONS: Free radical exists originally in pigment gallstones in vivo, and it may play an important role in pigment gallstone formation. The free radical signal carried by gallstones may be strengthened by the action of oxygen in air on bilirubin. The transition metal ions probably take part in the formation of bilirubin free radical.
Bilirubin↗
Essential region for self-replication of Coryneform bacteria plasmid pXZ10145.
A pTSK series of recombinant plasmids were constructed by cloning DNA fragments of pXZ10145 or its deleted deriviate pATN65 into plasmid vector pACYC177 of E. coli. Experiment results of Coryneform bacteria transformation with these pTSK plasmids allowed us to localize the essential region for self-replication on plasmid pXZ10145. The minimal replication region of the pXZ10145 was located on a 1.2kb Nael-Nrul DNA fragment in which only one open reading frame was found. This ORF was believed to be encoded a trans-acting replication factor. The replication origin (oriV) was locate on a 0.3kb NaeI-SalI fragment which was within the ORF region.
Actinomycetales↗
The factors affecting transformation efficiency of coryneform bacteria by electroporation.
High-voltage electroporation was performed to transfer plasmid DNA of pXZ10145 into different kinds of corynebacteria strains. A number of factors that affected transformation efficiency were investigated. Cells grown in the presence of 4% glycine and harvested in the early exponential growth phase (OD600 was about 0.2) were much more easily transformed. Transformation efficiency up to 8 x 10(6) transformants per microgram of plasmid DNA with homologously derived DNA was obtained. If heterologously derived DNA was used, transformation efficiency was 10(2) to 10(3) times lower than the former one.
Actinomycetales↗
The endoplasmic reticular heat shock protein gp96 is transcriptionally upregulated in interferon-treated cells.
A cDNA clone complementary to an interferon (IFN)-induced mRNA approximately 3 kb in length was identified and sequenced revealing homology with the endoplasmic reticular heat shock protein/ATPase gp96. Both IFN-alpha and -gamma transcriptionally upregulate expression of this gene. gp96 transcripts, protein, and ATPase activity are shown to be enhanced as a result of IFN treatment in two human cell lines and this effect requires de novo protein synthesis. gp96 molecules have recently been implicated in the presentation of endogenous antigens. A number of the key elements in this pathway, the transporter proteins, the major histocompatibility complex (MHC)-linked units of the proteasomes and the MHC class I molecules are known to be IFN inducible. Our results show that yet another molecule suggested to play an accessory role in the endogenous presentation pathway is IFN inducible. Further, our studies represent the first demonstration of modulation of expression of a heat shock protein by a cytokine and identify a new enzymatic activity upregulated in IFN-treated cells.
Adenosine Triphosphatases↗
STM study of surface reconstructions of Si(111):B.
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Journal Article↗
A novel myogenic regulatory circuit controls slow/cardiac troponin C gene transcription in skeletal muscle.
The slow/cardiac troponin C (cTnC) gene is expressed in three distinct striated muscle lineages: cardiac myocytes, embryonic fast skeletal myotubes, and adult slow skeletal myocytes. We have reported previously that cTnC gene expression in cardiac muscle is regulated by a cardiac-specific promoter/enhancer located in the 5' flanking region of the gene (bp -124 to +1). In this report, we demonstrate that the cTnC gene contains a second distinct and independent transcriptional enhancer which is located in the first intron. This second enhancer is skeletal myotube specific and is developmentally up-regulated during the differentiation of myoblasts to myotubes. This enhancer contains three functionally important nuclear protein binding sites: a CACCC box, a MEF-2 binding site, and a previously undescribed nuclear protein binding site, designated MEF-3, which is also present in a large number of skeletal muscle-specific transcriptional enhancers. Unlike most skeletal muscle-specific transcriptional regulatory elements, the cTnC enhancer does not contain a consensus binding site (CANNTG) for the basic helix-loop-helix (bHLH) family of transcription factors and does not directly bind MyoD-E12 protein complexes. Despite these findings, the cTnC enhancer can be transactivated by overexpression of the myogenic bHLH proteins, MyoD and myogenin, in C3H10T1/2 (10T1/2) cells. Electrophoretic mobility shift assays demonstrated changes in the patterns of MEF-2, CACCC, and MEF-3 DNA binding activities following the conversion of 10T1/2 cells into myoblasts and myotubes by stable transfection with a MyoD expression vector. In particular, MEF-2 binding activity was up-regulated in 10T1/2 cells stably transfected with a MyoD expression vector only after these cells fused and differentiated into skeletal myotubes. Taken together, these results demonstrated that distinct lineage-specific transcriptional regulatory elements control the expression of a single myofibrillar protein gene in fast skeletal and cardiac muscle. In addition, they show that bHLH transcription factors can indirectly transactivate the expression of some muscle-specific genes.
Amino Acid Sequence↗