The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform
Aziz Sancar - One of the best experts on this subject based on the ideXlab platform.
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Formation of a ternary complex by human XPA, ERCC1, and ERCC4(XPF) excision repair proteins
Proceedings of the National Academy of Sciences of the United States of America, 1994Co-Authors: Chi Hyun Park, Aziz SancarAbstract:The xeroderma pigmentosum complementation group A (XP-A) protein, XPA, has recently been expressed in Escherichia coli in a soluble and fully functional form. An affinity column was prepared by linking the XPA protein to a solid support. When HeLa cell-free extract capable of excision repair was applied to the column, > 99.9% of the proteins were in the flow-through. However, the flow-through Fraction lacked excision activity. The activity was restored by adding the high salt (1 M KCl) eluate of the column to the flow-through Fraction. The XPA Protein-Bound Fraction was tested for specific proteins by an in vitro complementation assay with a panel of cell-free extracts from DNA repair-deficient human and rodent cell lines. The XPA-bound Fraction complemented cell-free extracts of excision repair cross-complementing 1 (ERCC-1), ERCC-4 (XP-F), and XP-A mutants. We conclude that the XPA damage recognition protein makes a ternary complex with the ERCC1/ERCC4(XPF) heterodimer with a potential nuclease function.
H. E. Grates - One of the best experts on this subject based on the ideXlab platform.
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Testosterone concentration is increased in whole saliva, but not in ultrafiltrate, after toothbrushing.
Clinical chemistry, 1993Co-Authors: Willfried Schramm, Richard H. Smith, Paul A. Craig, H. E. GratesAbstract:The concentration of testosterone in whole saliva is significantly increased (by 9%) after toothbrushing. In ultrafiltrates of saliva collected at the same time as the whole saliva, testosterone concentrations after toothbrushing were unchanged. In 88% of the 162 whole-saliva specimens, but not in the ultrafiltrates, we also measured higher hemoglobin concentrations after toothbrushing. We conclude that the increase of testosterone in whole saliva after toothbrushing can be attributed to a Protein-Bound Fraction. For analytes that are bound to serum proteins, salivary measurements can give spurious results. This problem can be avoided by using as a diagnostic medium an ultrafiltrate of saliva collected directly in the mouth.
Anna Zaghini - One of the best experts on this subject based on the ideXlab platform.
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Pharmacokinetics of cefovecin sodium after subcutaneous administration to Hermann's tortoises (Testudo hermanni)
American journal of veterinary research, 2014Co-Authors: Giordano Nardini, Mattia Bielli, Nicola Di Girolamo, Andrea Barbarossa, Andrea Dall'occo, Petra Cagnardi, William Magnone, Paola Roncada, Anna ZaghiniAbstract:Objective—To determine the pharmacokinetics of cefovecin sodium after SC administration to Hermann’s tortoises (Testudo hermanni). Animals—23 healthy adult Hermann’s tortoises (15 males and 8 females). Procedures—Cefovecin (8.0 mg/kg) was injected once in the subcutis of the neck region of Hermann’s tortoises, and blood samples were obtained at predetermined time points. Plasma cefovecin concentrations were measured via ultraperformance liquid chromatography coupled to tandem mass spectrometry, and pharmacokinetic parameters were calculated with a noncompartmental model. Plasma protein concentration was quantified, and the percentage of cefovecin bound to protein was estimated with a centrifugation technique. Results—Cefovecin was absorbed rapidly, reaching maximum plasma concentrations between 35 minutes and 2 hours after administration, with the exception of 1 group, in which it was reached after 4 hours. The mean ± SD time to maximum concentration was 1.22 ± 1.14 hours; area under the concentration-time curve was 220.35 ± 36.18 hµg/mL The mean Protein-Bound Fraction of cefovecin ranged from 41.3% to 47.5%. No adverse effects were observed. Conclusions and Clinical Relevance—Administration of a single dose of cefovecin SC appeared to be well-tolerated in this population of tortoises. Results of pharmacokinetic analysis indicated that the 2-week dosing interval suggested for dogs and cats cannot be considered effective in tortoises; however, further research is needed to determine therapeutic concentrations of the drug and appropriate dose ranges. (Am J Vet Res 2014;75:918–923)
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Pharmacokinetics of cefovecin sodium after subcutaneous administration to Hermann's tortoises (Testudo hermanni)
'American Veterinary Medical Association (AVMA)', 2014Co-Authors: Giordano Nardini, Mattia Bielli, Nicola Di Girolamo, Andrea Barbarossa, Petra Cagnardi, William Magnone, Paola Roncada, A. Dall&apos, Anna ZaghiniAbstract:Objective-To determine the pharmacokinetics of cefovecin sodium after SC administration to Hermann's tortoises (Testudo hermanni). Animals-23 healthy adult Hermann's tortoises (15 males and 8 females). Procedures-Cefovecin (8.0 mg/kg) was injected once in the subcutis of the neck region of Hermann's tortoises, and blood samples were obtained at predetermined time points. Plasma cefovecin concentrations were measured via ultraperformance liquid chromatography coupled to tandem mass spectrometry, and pharmacokinetic parameters were calculated with a noncompartmental model. Plasma protein concentration was quantified, and the percentage of cefovecin bound to protein was estimated with a centrifugation technique. Results-Cefovecin was absorbed rapidly, reaching maximum plasma concentrations between 35 minutes and 2 hours after administration, with the exception of 1 group, in which it was reached after 4 hours. The mean \ub1 SD time to maximum concentration was 1.22 \ub1 1.14 hours; area under the concentration-time curve was 220.35 \ub1 36.18 h\u2022\u3bcg/mL The mean Protein-Bound Fraction of cefovecin ranged from 41.3% to 47.5%. No adverse effects were observed. Conclusions and Clinical Relevance-Administration of a single dose of cefovecin SC appeared to be well-tolerated in this population of tortoises. Results of pharmacokinetic analysis indicated that the 2-week dosing interval suggested for dogs and cats cannot be considered effective in tortoises; however, further research is needed to determine therapeutic concentrations of the drug and appropriate dose ranges
Chi Hyun Park - One of the best experts on this subject based on the ideXlab platform.
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Formation of a ternary complex by human XPA, ERCC1, and ERCC4(XPF) excision repair proteins
Proceedings of the National Academy of Sciences of the United States of America, 1994Co-Authors: Chi Hyun Park, Aziz SancarAbstract:The xeroderma pigmentosum complementation group A (XP-A) protein, XPA, has recently been expressed in Escherichia coli in a soluble and fully functional form. An affinity column was prepared by linking the XPA protein to a solid support. When HeLa cell-free extract capable of excision repair was applied to the column, > 99.9% of the proteins were in the flow-through. However, the flow-through Fraction lacked excision activity. The activity was restored by adding the high salt (1 M KCl) eluate of the column to the flow-through Fraction. The XPA Protein-Bound Fraction was tested for specific proteins by an in vitro complementation assay with a panel of cell-free extracts from DNA repair-deficient human and rodent cell lines. The XPA-bound Fraction complemented cell-free extracts of excision repair cross-complementing 1 (ERCC-1), ERCC-4 (XP-F), and XP-A mutants. We conclude that the XPA damage recognition protein makes a ternary complex with the ERCC1/ERCC4(XPF) heterodimer with a potential nuclease function.
S. V. Lupachyk - One of the best experts on this subject based on the ideXlab platform.
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Effect of oxidative stress on rat thyrocyte iodide metabolism.
Cell biochemistry and function, 2008Co-Authors: L. I. Nadolnik, Z. V. Niatsetskaya, S. V. LupachykAbstract:Thyroid cells fall into the type of cells functioning during continuous production of high H(2)O(2) concentrations. We studied the effect of H(2)O(2)-induced oxidative stress (0.1, 1.0 and 10.0 mM) on the activities of the key steps of iodide metabolism (uptake, oxidation and organification) in thyrocytes cultivated in an organ culture. After 60 min cultivation of cells in a medium containing H(2)O(2) at concentrations of 1.0 and 10.0 mM iodide (I(-)) uptake, thyroperoxidase (TPO) activity and I(-) organification were completely inhibited. No restoration of the parameters studied was observed within the subsequent 24 h of cultivation. The inhibitory effect of 0.1 mM H(2)O(2) was reversible. Activation of I(-) uptake in the cultivated tissue and a 520-880% increase of the total I(-) content were observed after 8 and 24 h. The concentration of I(-) Protein-Bound Fraction was raised by 220% after 24 h. A biphasic effect of 0.1 mM H(2)O(2) on TPO was observed: 76.2% and 72.2% inhibitions were seen after 2 and 8 h, respectively, whereas 40.0% enzyme activation was after 5 h. TPO activity was partially restored after 24 h and amounted to 65% of the initial value. The significant increase in the concentration of iodide Protein-Bound Fraction, which was observed simultaneously with TPO inhibition, could be due to thyroglobulin non-enzymic iodination under H(2)O(2)-generated oxidative stress. The data obtained indicate that iodide oxidation, as a step in the biosynthesis of thyroid hormones, was most sensitive to oxidative stress activation. The impaired iodide uptake and its organification during oxidative stress can play a pathogenetic role in disturbed functions of thyroid cells.
