Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to evaluate the importance of glycogen for the hepatic tolerance to ischemia, livers of swine fed a glucose-potassium solution for premedication were perfused with either Bretschneider's HTK-solution (histidine-tryptophan-ketoglutarate) or with Euro-Collins-solution (EC) prior to subsequent ischemia at 25 and 5 degrees C. During ischemia, in regular intervals or continuously, energy rich phosphates, lactate, intrahepatic pH and the electrical impedance of liver tissue were determined. The results were compared with corresponding data from swine which had starved for 48 h. Corresponding to the higher glycogen content, energy supply during ischemia was markedly improved by the premedication. Despite high amounts of glucose in the EC-solution, energy supply after glucose-potassium premedication was no better with EC-solution than with HTK-solution. Moreover, glucose uptake led to concomitant cellular water uptake. Electrical impedance measurements during ischemia mirrored improved energetical protection by the glucose-potassium premedication.
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PMID:Glycogen effects on energy state and passive electric properties of liver during protection. 211 13

Endothelial cell damage caused by myocardial cardioplegic solutions (Bretschneider HTK and St. Thomas' Hospital No. 2) or renal and hepatic cold storage solutions (modified Collins and University of Wisconsin solution) was assessed in monolayer cultures of adult human venous endothelial cells at 4 degrees to 10 degrees C with phase-contrast microscopy. St. Thomas' Hospital solution caused the cells to contract, resulting in disruption of monolayer integrity and opening of intercellular gaps, and resulted in a 24-hour postexposure survival of 51.0% +/- 2.4%. Bretschneider HTK solution altered cellular morphology less and produced the best postexposure survival (80.2% +/- 2.6%; p less than 0.001). Although morphology was altered the least with University of Wisconsin solution, postexposure survival with this solution, which was similar to that with modified Collins solution, was superior to that with St. Thomas' (p less than 0.01) but inferior to that with Bretschneider HTK (p less than 0.05). The superior protection provided by Bretschneider HTK was due to its additives histidine, tryptophan, and KH-2-oxygluterate (p less than 0.005), and to its low chloride content (p less than 0.005). Furthermore, modifying St. Thomas' solution by decreasing its chloride content improved cell survival to 71.2% +/- 2.3% (p less than 0.001). Normothermic (37 degrees C) exposure to Bretschneider HTK, modified Collins, and University of Wisconsin solution was cytotoxic, whereas normothermic exposure to St. Thomas' cardioplegia was not. In conclusion, the preservation solution that is the least harmful to endothelial cells at hypothermia is Bretschneider HTK cardioplegic solution.
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PMID:Endothelial cell toxicity of solid-organ preservation solutions. 212 22

Phospholipase C-gamma (PLC-gamma) and GTPase activating protein (GAP) are substrates of EGF, PDGF and other growth factor receptors. Since either PLC-gamma or GAP also bind to the activated receptors it was suggested that their SH2 domains are mediating this association. We attempted to delineate the specific region of the EGF receptor that is responsible for the binding, utilizing EGF receptor mutants, PLC-gamma, and a bacterially expressed TRP E fusion protein containing the SH2 domains of GAP. As previously shown, tyrosine autophosphorylation of the wild-type receptor wsa crucial in mediating the association and in agreement, a kinase negative EGF receptor could bind PLC-gamma or TRP E GAP SH2, but only when cross tyrosine phosphorylated by an active EGF receptor kinase. The importance of autophosphorylation for association was confirmed by demonstrating that a carboxy-terminal deletion of the EGFR missing four autophosphorylation sites bound these proteins poorly. To study the role of EGF receptor autophosphorylation further, a 203 amino acid EGF receptor fragment was generated with cyanogen bromide that contained all known tyrosine autophosphorylation sites. This fragment bound both TRP E GAP SH2 and PLC-gamma but only when tyrosine phosphorylated. This data localizes a major binding site for SH2 domain containing proteins to the carboxy-terminus of the EGF receptor and points to the importance of tyrosine phosphorylation in mediating this association.
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PMID:The tyrosine phosphorylated carboxyterminus of the EGF receptor is a binding site for GAP and PLC-gamma. 217 51

The ischemic damage following liver transplantation (LTX) is predominantly located at the endothelial cell level and is a major cause for a disturbance of microcirculation. The present study was designed to test the hypothesis that changes in the quality of organ preservation are correlated with changes in microcirculation: 16 pigs underwent LTX, preservation by Bretschneider's HTK-solution (Histidin, Tryptophan, alpha-Ketoglutarat) complemented by indomethacin (50 mumol/L). Cold ischemia times were 9 hr (n = 8) and 18 hr (n = 8), respectively. Using the H2-clearance technique, hepatic microcirculation was measured before, 30 min, and 20 hr after LTX. Normal tissue perfusion was 107 +/- 16 ml/100 g/min, at 30 min posttransplantation 91 +/- 13 ml/100 g/min in the short-term and 48 +/- 7 ml/100 g/min in the long-term preservation group. Whereas no animal of the long-term preservation group survived longer than 8 hr, all animals of the short-term preservation group survived, and tissue perfusion could be measured 20 hr postoperatively (101 +/- 19 ml/100 g/min). At 30 min postoperatively, all surviving animals had tissue perfusion rates greater than 70, and all nonsurvivors had values below 60 ml/100 g/min. We conclude therefore that the extent of decrease of microcirculation after LTX may be a useful predictor of organ function and survival.
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PMID:Evaluation of preservation damage after porcine liver transplantation by assessment of hepatic microcirculation. 225 66

In order to determine the effects of large variations in plasma amino acid concentrations upon human erythrocyte amino acid content, the plasma concentration of blood samples was enhanced (x 3.8) by adding amino acids or decreased (x 0.49) by plasma dilution. Before and after incubation (30 s at 37 degrees C), the erythrocyte contents were calculated from whole blood and plasma amino acid concentrations. Large and rapid plasma concentration variations led to significant erythrocyte changes in 11 amino acids. THR, CIT, alpha AB, VAL, MET, ILE, LEU, TYR, PHE, TRP, and ARG. Relationships between erythrocyte and plasma concentrations were determined for these amino acids. These observations were examined in the light of the role played by erythrocytes in blood amino acid transport.
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PMID:The effects of changes in plasma amino acid concentrations on erythrocyte amino acid content. 237 38

Interferon-gamma-induced tryptophan metabolism of human macrophages was compared to ten human neoplastic cell lines of various tissue origin and to normal dermal human fibroblasts. Tryptophan and metabolites were determined in supernatants of cultures, after incubation for 48 h, by high-performance liquid chromatography with ultraviolet and fluorescence detection. With the exception of two cell lines (Hep G 2, hepatoma and CaCo 2, colon adenocarcinoma) in all of the ten other cells and cell lines tryptophan degradation was induced by interferon-gamma. Five of these ten formed only kynurenine (SK-N-SH, neuroblastoma; T 24, J 82, bladder carcinoma; A 431, epidermoid carcinoma; normal dermal fibroblasts), three formed kynurenine and anthranilic acid (U 138 MG, glioblastoma; SK-HEP-1, hepatoma; A 549, lung carcinoma). Only one line, A 498 (kidney carcinoma) showed the same pattern of metabolites as macrophages (kynurenine, anthranilic acid and 3-hydroxyanthranilic acid). Interferon-gamma regulated only the activity of indoleamine 2,3-dioxygenase. All other enzyme activities detected were independent of interferon-gamma, as shown by the capacity of the cells to metabolize L-kynurenine or N-formyl-L-kynurenine. Increasing the extracellular L-tryptophan concentration resulted in a marked induction of tryptophan degradation by macrophages. Contrarily, a significant decrease of the tryptophan degrading activity was observed when the extracellular L-tryptophan concentration was increased 2-fold with SK-N-SH, T 24 and J 82, 4-fold with A 431 and A 549 and 10-fold with U 138 MG and SK-HEP-1. The activity was unaffected by extracellular L-tryptophan with dermal fibroblasts and A 498. Though interferon-gamma was the most potent inducer of tryptophan metabolism, interferon-alpha and/or -beta showed small but distinct action on some of the cells. In all cells which reacted to interferon-gamma by enhanced expression of class I and/or class II major histocompatibility complex antigens tryptophan degradation was also inducible. These results demonstrate that induction of indoleamine 2,3-dioxygenase is a common feature of interferon-gamma action, that the extent of this induction is influenced by extracellular L-tryptophan concentrations and that indoleamine 2,3-dioxygenase is the only enzyme in the formation of 3-hydroxyanthranilic acid from tryptophan which is regulated by interferon-gamma.
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PMID:Characteristics of interferon induced tryptophan metabolism in human cells in vitro. 250 Sep 76

The mouse aprt promoter contains four GC boxes, which bind transcription factor Spl in vitro, and lacks both TATA and CCAAT boxes. Removal of the two most distal GC boxes of this promoter had little effect on APRT enzyme levels produced in a transient expression assay. Deletion of the distal three GC boxes resulted in a 50% reduction, and deletion of all GC boxes resulted in essentially complete loss of APRT activity. There are two predominant transcription start sites which are located within the region containing the GC boxes. The promoter behaved as a relatively strong promoter when compared to the RSV LTR promoter in a transient CAT assay, and operated in one orientation only. No upstream anti-sense transcripts were detected in either mouse CAK or liver cells, confirming that the mouse aprt promoter, unlike some other GC-rich promoters appears not to support bidirectional transcription.
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PMID:Identification of DNA sequences required for mouse APRT gene expression. 290 25

We have constructed two recombinant plasmid vectors for direct expression and amplification of cDNA in mammalian cells. Each vector carries two dominant selectable markers (the bacterial neo gene and the mouse DHFR gene), a promoter sequence (viral LTR in pAV009/A+, and sheep metallothionein promoter in pMT010/A+), a polyadenylation signal sequence, and a Bam HI site to allow insertion of cDNA. We have used these vectors to prepare recombinant clones for the expression of rat phenylalanine hydroxylase (PH) in LTK- cells. Selection of transformants with neomycin followed by selection of the transformants in methotrexate led to a 30- to 60-fold amplification of the DHFR marker and co-amplification of the PH cDNA, with a corresponding increase in the level of PH mRNA and enzyme polypeptide. The expressed enzyme has a subunit molecular weight of 50,000 which corresponds to the W- allele of rat liver PH. PH activity was detected in the transfected cells by enzymatic measurement of the conversion of [14C]phenylalanine to [14C]tyrosine, and by growth of these cells in a tyrosine-free culture medium. Expression of rat PH in cell culture should facilitate the analysis of the biochemical properties of this enzyme.
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PMID:Vectors for expression and amplification of cDNA in mammalian cells: expression of rat phenylalanine hydroxylase. 302 40

A new amphibian peptide family has been isolated from the skin of a South American frog Phyllomedusa rhodei and named Tryptophyllins (TPH) because of their content in tryptophyl residue. Using an antiserum against one of these peptides, namely the pentapeptide Met-5-TPH-5-amide (PHE-PRO-PRO-TRP-MET-NH2), we observed the presence of a set of immunoreactive cells in rat adenohypophysis. These cells were far more numerous in pregnant than in normal male and non-pregnant female rats. Dual immunostainings demonstrated that, with some exceptions, almost all the TPH-like immunoreactive cells were gonadotrophs. At electron microscope both types of gonadotroph cells displayed immunoreactivity and the gold particles strongly labelled both types of granules. The Aa. advance the hypothesis that, besides the hormones themselves, the secretory granules might contain some TPH-like sequence.
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PMID:Tryptophyllin-like immunoreactivity in rat adenohypophysis. 391 5

A new family of retroviral long terminal repeats that we name Spm-LTR has been identified as a result of DNA sequence comparisons between the entire GenBank databank and an element, SPHP, located 5' to the haptoglobin gene of spider monkeys. The 18 human Spm-LTR sequences so identified fall into three subtypes. There is no sequence similarity between Spm-LTR elements and any endogenous retroviral LTR sequences previously reported except for general features that define LTRs. However, a previously described repeated sequence (MER-4) forms a portion of the Spm-LTR sequence.
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PMID:A new family of retroviral long terminal repeat elements in the human genome identified by their homologies to an element 5' to the spider monkey haptoglobin gene. 755 37


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