Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.3.4.6 (urease)
 7,490 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The hydrophobic nature of proteins is characterized by a degree of 2-p-toluidinonaphthalene-6-sulphonate (TNS) affinity to them and is pronounced quantitatively in the semi-saturated (C1/2) concentrations. This index correlates directly with the position of TNS emission maximum after the binding with proteins and reversely with the yield of fluorescence. The preparations of phosphofructokinase, lactate dehydrogenase, xantinoxidase, glyceratekinase, lysozyme, RNase during the long (1-2 h) contact with TNS change the values C1/2, that evidences for interaction with the hydrophobic indicator of new structures of protein molecule or for a change in the nature of its linkage itself. An attempt is made to characterize the accessible for TNS hydrophobic nature of individual proteins by a coefficient of molar hydrophobic nature which unites three mentioned characteristics. Serum albumin, insulin, glucogon, alpha chemotrypsin, DNase are most hydrophobic, pyruvate kinase, aldolase, urease, RNase--least hydrophobic, Glycerate kinase, pyruvate decarboxylase, phosphofructokinase, lactate dehydrogenase, alcohol dehydrogenase, xanthinoxidase, trypsin, lysozyme are in intermediate position.
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PMID:[Comparative characteristics of hydrophobic nature of certain proteins by their interaction with 2-p-toluidinonaphthalene-6-sulfonates]. 120 4

Beagle serum proteins were separated by polyacrylamide gel electrophoresis (PAGE) and the electrophoretograms were examined by one- and two-dimensional analyses with a laser densitometer. In order from the anodic side of the PAGE pattern, pre-albumin, hexokinase, tyrosinase, alkaline phosphatase, urease, and aldehyde dehydrogenase were assumed to be present based on Rf and Mw. Serum albumin, lactate dehydrogenase, and catalase appeared to be present based on a comparison of their electrophoretic mobility with that of protein standards of known Mw. Verification of beagle serum protein fractions by immunofixation electrophoresis and western blotting electrophoresis, with rabbit anti-human serum, indicated alpha 1-antitrypsin, albumin, haptoglobin, ceruloplasmin, C3c complement, IgG, and IgA. Serum protein fraction values (%) obtained by one- and two-dimensional analyses were similar.
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PMID:Analysis of a polyacrylamide gel electrophoretogram of beagle serum protein by laser densitometer. 765 Sep 2

By means of harmonic imaging, it is possible to display brain perfusion qualitatively using ultrasound (US) contrast agent (UCA) bolus injection. With UCA continuous infusion reaching a steady state, mean microbubble velocity can be measured, analyzing the reappearance rate after microbubble destruction by US (refill kinetics). We performed an animal pilot study to investigate this new method for the assessment of brain perfusion. Using harmonic grey-scale imaging, five sedated male beagle dogs were investigated through the intact skull with increasing pulsing intervals (250 to 8000 ms) and three UCA infusion rates (0.5, 1.0 and 1.5 mL/min of Optison). Cerebral blood flow was increased by acetazolamide (30 mg/kg BW). Intensity vs. pulsing interval curves were analyzed using an exponential curve fit [I(t) = A(1-e(-beta t))] and parameters of the curve were compared. We found that increasing the pulsing interval above 4000 ms led to no further increase of echo enhancement for infusion rates. Mean beta values were not influenced by infusion rate (p = 0.25 and p = 0.55). Mean F values increased nonsignificantly with rising infusion rate (p = 0.25 and p = 0.86). Acetazolamide led to an increase of mean beta and F values (p = 0.18 and p = 0.025, respectively). It is possible to evaluate changes in brain perfusion through the intact skull by analyzing the UCA refill kinetics after US-induced microbubble destruction.
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PMID:Evaluation of blood flow in the cerebral microcirculation: analysis of the refill kinetics during ultrasound contrast agent infusion. 1152 92

With ultrasound (US) contrast agent (UCA) continuous infusion providing a steady state, mean tissue microbubble velocity can be assessed by analyzing the reappearance rate after microbubble destruction with US energy (refill kinetics). In this study, we investigated this new approach for the assessment of human cerebral perfusion. A total of 12 healthy volunteers were investigated transtemporally with increasing pulsing intervals (250, 500, 750, 1000, 1250, 1500, 2000, 3000 and 4000 ms) and two UCA infusion rates (0.5 and 1.0 mL/min of Optison). Intensity vs. pulsing interval curves were analyzed using an exponential curve fit and parameters of the curve (plateau echo enhancement, A, representing the microbubble concentration within the interrogated tissue; rate constant, beta, which is related to blood flow and their product, F = Abeta) were compared. For 20/20 investigations being available for further analysis, it was possible to generate a typical exponential intensity vs. pulsing interval curve from the ipsilateral thalamus. The plateau echo enhancement A showed a significant (p = 0.02), and the beta as well as the F values displayed a nonsignificant (p = 0.06, both), increase with infusion rate. The qualitative analysis of beta and F parameter images displayed the most homogeneous visualisation of perfusion in the ipsilateral thalamus and main territory of the middle cerebral artery. In conclusion, it is possible to display the UCA refill kinetics in human cerebral microcirculation after microbubble destruction by transcranial US. Grey-scale harmonic imaging allows a quantitative approach to cerebral perfusion with a large interindividual variation of the parameters.
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PMID:Human cerebral perfusion analysis with ultrasound contrast agent constant infusion: a pilot study on healthy volunteers. 1193 80

Analysis of contrast diminution kinetics after bubble destruction is a new aspect in harmonic imaging. The purpose of this study was to investigate this approach to human cerebral perfusion. A total of 12 healthy volunteers were investigated transtemporally (Philips SONOS 5500, S4-probe, 1.8 to 3.6 MHz, 10 cm) at two ultrasound (US) contrast agent (UCA) infusion rates (0.5 and 1.0 mL/min of Optison). After achieving a steady-state, a set of 12 US pulses (6.67 Hz, MI 1.6) was applied. Time-intensity plots of three regions-of-interest (ROIs) (thalamus, white matter and cortex) were analyzed, using an exponential curve fit (I((t)) = I(0)e(-betat) + B). A total of 20 of 20 successful investigations showed a signal decrease after pulsed US application. In all cases, it was possible to generate exponential time-intensity curves. Half-life (T(1/2) = ln2/beta) and baseline intensity (B) showed a significant dependence on infusion rate (p = 0.01). At 1.0 mL/min, T(1/2) also depended on investigation depth (p = 0.01). It is possible to assess contrast diminution kinetics in human cerebral microcirculation. This new approach may provide additional information on cerebral perfusion within a short investigation time.
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PMID:Transcranial contrast diminution imaging of the human brain: a pilot study in healthy volunteers. 1249 38

Noninvasive measurement of pressure within the heart cavities and other internal organs (e.g., kidney, liver) has significant clinical value, but currently is not feasible. Noninvasive pressure estimation using encapsulated ultrasound (US) contrast agents (UCA) as sensors is a challenge because they supposedly respond to their ambient pressure, but they are more rigid and less sensitive to pressure than gas microbubbles. Here, Optison sensitivity was studied (f(resonance) = approximately 2 MHz) to varying pressures, when excited at 2 times and also at 0.5 times f(resonance). Cyclic momentary increases in ambient pressure of 0 to 5, 0 to 10, 0 to 15 or 0 to 20 kPa at 1.0 Hz, mimicking left ventricular (LV) pressure changes, caused amplitude decrease of echoes at 0.5, 1 and 2 times the transmitted frequency and decrease of attenuation. Changes at 0.5 times the transmitted frequency correlated best, but only after 70 to 150 s. The correlations (mean +/- SD) during 150 to 300 s were 0.706 +/- 0.072 for 0 to 10 kPa, 0.844 +/- 0.042 for 0 to 15 kPa and 0.859 +/- 0.031 for 0 to 20 kPa. Attenuation presented less correlation. For 1.0 Hz, 10 to 15 kPa or 15 to 20 kPa pressures, mimicking systemic pressures, the attenuation decayed fast and even faster for slow (0.05 Hz) cyclic varying pressures, or elevated steady-state pressures (of 10 kPa and 20 kPa). Thus, cyclic pressure effects on UCA are demonstrated to be reversible, but elevated static pressures cause UCA destruction. This allows cyclic pressure variations to be detected, using the subharmonics of the transmitted frequency, down to 10 kPa.
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PMID:On the relationship between encapsulated ultrasound contrast agent and pressure. 1586 17

INTRODUCTION. Helicobacter pylori infection in gastric mucosa may cause systemic inflammatory reaction. We investigated the inflammatory effect of H pylori infection on nutritional factors such as serum albumin in hemodialysis patients and influence of eradication of H pylori on this association. MATERIALS AND METHODS. Ninety-eight patients on hemodialysis were divided into 2 groups according to H pylori infection. Eradication of H pylori, 8 weeks after treatment, was confirmed by urease breath test and H pylori stool antigen. Serum albumin, lipid profile, and metabolite levels were checked before and after 8 weeks and 6 months of eradication of H pylori. RESULTS. Thirty-nine patients (39.8%) were infected with H pylori. There were no significant differences between the two groups in age, dialysis duration, serum albumin, serum creatinine, blood urea nitrogen, hemoglobin, serum calcium, serum phosphorus, and lipid profile. Thirty-seven patients with H pylori completed the treatment period. Eradication was successful in 30 patients (81.1%). Eight weeks and 6 months after anti-H pylori drug therapy, the mean serum albumin level significantly decreased from 4.2 mg/dL to 3.6 mg/dL (P < .001) and 3.7 mg/dL (P < .001), respectively. Significant decreases were seen in serum cholesterol (P = .001), blood urea nitrogen (P = .005), and serum calcium level (P = .03) and a significant increase in hemoglobin level (P = .02). CONCLUSIONS. Our study did not demonstrate nutritional benefits after H pylori eradication treatment, as the level of nutritional markers reduced. This relationship needs to be confirmed by further prospective studies.
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PMID:Association of Helicobacter pylori infection and serum albumin in patients on hemodialysis. 2085 73