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:2.7.1.21 (thymidine kinase)
7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

I have reviewed the current status of microinjection based on fusion of red blood cells and tissue culture cells. Macromolecules are introduced into red blood cells during hypotonic hemolysis, and the resealed red cells are then fused to tissue culture cells with Sendai virus. The procedure has been used to inject ferritin, thymidine kinase, bovine serum albumin, and transfer RNA molecules into large numbers of tissue culture cells. Physiologically significant amounts of various macromolecules can be transferred, and preliminary studies show that [125I]bovine serum albumin and transfer RNA are stable within recipient culture cells. Tissue culture cells remain viable following microinjection. Red cell-mediated microinjection should facilitate the study of various processes, such as macromolecular turnover and genetic regulation, that are not easily studied with conventional biochemical techniques.
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PMID:Red cell-mediated microinjection. 37 19

A single dose of erythropoietin stimulates DNA synthesis in the spleen of the polycythemic mouse with the maximum effect occurring 48 h after the hormone is administered. The increase in DNA synthesis is accompanied by morphologic evidence of increased erythropoiesis and by increases in the activities per cell of both thymidine kinase and cytoplasmic high molecular weight DNA polymerase-alpha. The activity of low molecular weight DNA polymerase-beta does not change significantly. Spleen cells from mice which had received either erythropoietin or saline 48 h previously were separated into 7 density classes on discontinuous bovine serum albumin gradients. Following the administration of erythropoietin, thymidine incorporation and thymidine kinase activity showed the greatest relative increases per nucleated cell in layers 3, 4 and 5 of the gradient. DNA polymerase-alpha showed the greatest increase in cells of the denser layers 5, 6 and 7. Each layer contained normoblasts and lymphocytes. The less well differentiated erythroid elements constituted a larger proportion of cells in layers of lower density. Increases in the rates of thymidine incorporation were better correlated with increases in thymidine kinase activity than with increases in DNA polymerase activities. Measurement of iron incorporation into heme confirm the morphological impression that the cell type responsible for increased thymidine incorporation and increased DNA polymerase-alpha activity is the young normblast.
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PMID:DNA polymerase, thymidine kinase and DNA synthesis in erythropoietic mouse spleen cells separated on bovine serum albumin gradients. 125 82

Adjacent peptide segments covering the complete sequence of herpes-simplex-virus type-1 thymidine kinase (HSV1-TK) of 376 amino acids were synthesized in order to experimentally verify the three-dimensional structure of the HSV1-TK active site, which was previously determined by molecular modeling. 26 peptides have been prepared by multiple solid-phase synthesis using the 9-fluorenylmethoxycarbonyl strategy. The purified peptides were linked covalently to bovine serum albumin. The peptide/ELISA of the synthesized bovine-serum-albumin conjugates using polyclonal rabbit anti(HSV1-TK)serum resulted in ten epitopes, which correlate excellently with the computer-proposed active site of HSV1-TK. CD spectra of the HSV1-TK peptides were recorded in trifluoroethanol/water (9:1 by vol.) An eigenvalue method based on CD spectra of 15 well known protein structures was used to calculate the relative percentage of secondary structures from the CD data. The computer model of the HSV1-TK showed full conformity with the folding pattern determined by CD of the synthetic peptide segments. Therefore, conformational peptide mapping with CD-based secondary structures combined with epitope mapping from the peptide/ELISA is an efficient and reliable method to support computer-aided protein design.
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PMID:Conformational and epitope mapping of herpes-simplex-virus type-1 thymidine kinase using synthetic peptide segments. 171 3

To evaluate the clinical applications of serum thymidine kinase (TK) activity, we compared the results obtained with this parameter with those of other liver function tests in 27 patients with acute viral hepatitis and 16 normal controls. In those in the acute stage, the serum TK activity increased significantly to 55.5 +/- 66.5 U/L. There was no significant correlation between serum TK activity and findings for serum albumin, bilirubin, alkaline phosphatase or r-glutamyl transpeptidase. However, it did correlate significantly well with the serum activity of aspartate aminotransferase (AST) (r = 0.621, P < 0.01), alanine aminotransferase (ALT) (r = 0.551, P < 0.01), and lactate dehydrogenase (LDH) (r = 0.620, P < 0.01). Serum TK activity reached higher than 70 U/L in 8 of 11 patients with hepatitis A; however, no patients with the other types of hepatitis reached such a high level. During the recovery stage, the serum TK activity decreased significantly to 5.9 +/- 1.7 U/L (P < 0.01), and did not correlate with AST, ALT, LDH or other conventional liver function parameters. The data suggest that an elevation of serum TK in patients with acute viral hepatitis results from hepatocellular damage. A marked elevation of serum TK activity may thus provide a marker for acute hepatitis A infection.
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PMID:Elevated serum thymidine kinase activity in patients with acute viral hepatitis. 844 Apr 24

The plasma cell labeling index (PCLI) and serum beta 2-microglobulin (beta 2M) are independent prognostic factors in multiple myeloma (MM). Recently, levels of thymidine kinase (TK) and C-reactive protein (CRP) have been shown to have prognostic value. We studied 107 patients with newly diagnosed myeloma to determine whether TK and CRP values added prognostic information not already available using the PCLI and beta 2M. Univariate survival analysis showed prognostic significance for the PCLI, TK, beta 2M, age, serum albumin, and CRP. Multivariate analysis showed that only PCLI and beta 2M have independent prognostic significance. The survival curves were better separated using the PCLI and beta 2M than with other combinations of variables. Among nine patients under age 65 with low PCLI and low beta 2M, eight were alive almost 6 years after starting chemotherapy. These good-risk patients could not be identified by standard clinical features. Although creatinine and calcium were normal, other features such as bone lesions, osteoporosis, fracture, and anemia were present and stage distribution was similar to other patients in the study. In conclusion, PCLI and beta 2M measured at diagnosis are independent prognostic factors. They must be considered when interpreting the results of clinical trials and should be helpful in counseling patients and in designing new trials. When the PCLI and beta 2M values are known, the TK and CRP values do not add useful additional prognostic information.
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PMID:Plasma cell labeling index and beta 2-microglobulin predict survival independent of thymidine kinase and C-reactive protein in multiple myeloma. 824 20

The median duration of survival for patients with multiple myeloma ranges from 2.5 to 3 years. However, there is considerable variability from one patient to another. Renal function as determined from blood urea nitrogen or serum creatinine values, hemoglobin value, calcium level and performance status have been recognized as prognostic factors for more than 20 years. A study of 107 patients with newly diagnosed multiple myeloma at the Mayo Clinic showed that plasma cell labeling index (PCLI); levels of thymidine kinase, beta 2-microglobulin (beta 2-M), serum albumin, and C-reactive protein; and age were all significant univariate prognostic factors. Only PCLI and beta 2-M levels had independent prognostic significance. Among nine patients younger than 65 years with low PCLI and low beta 2-M levels, eight were alive almost six years after starting chemotherapy. Interleukin 6 (IL-6) is a significant univariate predictor of survival in myeloma. An elevated lactate dehydrogenase content is associated with a poor prognosis. An elevated soluble IL-6 receptor (sIL-6R) level is an independent factor associated with shorter survival. In one study, the addition of sIL-6R to PCLI and beta 2-M to the analysis doubled the proportion of patients identified as high-risk. In this study, the two-year survival was 41% at two years if the PCLI was > or = 2%, beta 2-M was > or = 4.0 micrograms/dl, or sIL-6R was > 300 ng/ml. When none of these three factors were increased, the estimated two-year survival was 83%.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Prognostic factors in multiple myeloma. 852 May 13

Serum selenium levels were determined cross-sectionally in 57 HIV-infected patients who were classified according to the Centers for Disease Control (CDC) 1993 classification system. Mean serum selenium levels were lower in CDC stage II (58.7 +/- 12.2 micrograms/L; p < 0.01; n = 18) and stage III (47.6 +/- 11.3 micrograms/L; p < 0.01; n = 19) HIV-infected patients, than in healthy subjects (80.6 +/- 9.6 micrograms/L; n = 48) and stage I patients (73.6 +/- 16.5 micrograms/L; n = 20). Serum selenium levels were positively correlated with CD4 count, CD4/8 ratio, hematocrit, and serum albumin (r = 0.42; r = 0.39; r = 0.48; and r = 0.45; p < 0.01, respectively) and inversely with serum levels of thymidine kinase (r = -0.49; p < 0.01; n = 49) and beta 2-microglobulin (r = -0.46; p < 0.001; n = 49). In addition, serum selenium levels in 20 randomly selected AIDS-free individuals (CDC I: n = 10; CDC II: n = 10) were inversely correlated with serum concentrations of interleukin-8 (IL-8) and soluble tumor necrosis factor receptors (sTNFR) types I and II. There was no correlation with serum immuneglobulin A and total serum protein levels. The results show that the progressive deprivation of serum selenium in HIV-infection is associated with loss of CD(4+)-cells and with increased levels of markers of disease progression and inflammatory response.
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PMID:Serum selenium versus lymphocyte subsets and markers of disease progression and inflammatory response in human immunodeficiency virus-1 infection. 915 10

We have demonstrated that in rats subjected to partial hepatectomy (PH), the regenerating liver had an enhanced metabolism of ethanol, which largely depended on the route and timing of ethanol administration. Therefore, the influence of the administration route and timing for ethanol-induced deleterious effects on the regenerating rat liver was evaluated in animals subjected to 70% PH. Remnant liver showed moderate fatty infiltration, extended distortion of hepatocellular structure, and high mitotic index. Intragastric ethanol administration (1.5 g/kg body weight) considerably reduced the PH-induced changes in liver structures. Ethanol treatment also decreased liver thymidine kinase activity, serum albumin, and glucose levels. Intraperitoneal administration of the same ethanol dose to PH rats promoted lesser alterations on liver regeneration. Independently of its administration route, ethanol abruptly shortened a PH-induced selective increase in serum enzyme activities. These data suggest that the inhibitory effect of a low dose of ethanol on PH-induced liver regeneration is dependent on the timing and route of administration.
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PMID:Morphological and biochemical effects of a low ethanol dose on rat liver regeneration: role of route and timing of administration. 1054 44

This report describes the evolution of hepatocytes isolated from 21-day fetuses and transplanted into spleens of Nagase analbuminemic rats which have negligible serum albumin levels due to a mutation affecting albumin mRNA processing. Albumin and alpha-fetoprotein expression, in addition to other parameters related to cellular proliferation status (thymidine kinase and proliferating cell nuclear antigen expression) were studied as indicative of the behavior and evolution of the cells. In recipient rats, only a few clusters of hepatocytes could be observed in the red pulp of the spleen 24 h after transplantation. The fetal hepatocytes migrated to the liver and could be seen in portal branches immediately after transplantation. Fifteen days later, albumin mRNA was detected in recipient livers and was expressed throughout the entire 3-month study. Alpha-fetoprotein was not detected. Cell proliferation was not relevant, although 3 months after transplantation, the proliferation rates appeared to show a tendency to increase. These data demonstrate that fetal hepatocytes transplanted into spleen migrate to liver, settle there and acquire an adult phenotype free of malignant transformation. Our study is a first step towards the thorough understanding of fetal hepatocyte transplantation. The next steps will involve in-depth studies of the possibilities of genetic manipulation to achieve a high degree of repopulation/expression, employing the least possible number of donor cells, and of how the cells reach the liver parenchyma, overcoming the endothelial barrier.
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PMID:Liver gene expression and increase in albumin synthesis by fetal hepatocytes transplanted into analbuminemic rats. 1106 65

The shortage of organ donors has impeded the development of human hepatocyte transplantation. Immortalized hepatocytes could provide an unlimited supply of transplantable cells. To determine whether immortalized hepatocytes could provide global metabolic support in end-stage liver disease, 35 immortalized rat hepatocyte clones were developed by transduction with the gene encoding the simian virus 40 T antigen (SV40Tag). The SV40Tag sequence and a suicide gene, herpes simplex virus thymidine kinase (HSV-tk), were flanked by loxP sequences so that they could be excised by Cre/lox recombination. When transplanted into the spleens of portacaval-shunted rats, 3 of the 35 immortalized hepatocyte clones prevented the development of hyperammonemia-induced hepatic encephalopathy. The protection was reversed by treatment with ganciclovir, which kills HSV-tk-expressing cells. Transplantation of alginate-encapsulated, immortalized hepatocytes into the spleens of cirrhotic rats resulted in significant improvement in prothrombin time, serum albumin and bilirubin levels, hepatic encephalopathy score, and duration of survival. The metabolic support provided by the immortalized cells equaled that observed after transplantation of primary rat hepatocytes. In conclusion, immortalized hepatocytes can function as well as primary hepatocytes following transplantation and can be engineered to contain safeguards that could make them clinically useful. Further investigation is warranted regarding the mechanisms of loss of mass or function of the transplanted hepatocytes over time and how the relatively few engrafted hepatocytes can ameliorate liver decompensation in cirrhosis.
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PMID:Treatment of liver failure in rats with end-stage cirrhosis by transplantation of immortalized hepatocytes. 1214 47


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