scholarly journals Assessment of Micral-Test Microalbuminuria Test Strip in the Laboratory and in Diabetic Outpatients

1992 ◽  
Vol 29 (1) ◽  
pp. 96-100 ◽  
Author(s):  
Denis R Jury ◽  
Donald J Mikkelsen ◽  
Deborah Glen ◽  
Peter J. Dunn
Keyword(s):  
Screening Method ◽  
Urine Osmolality ◽  
Test Strip ◽  
Albumin Concentration ◽  
Creatinine Concentration ◽  
Urine Albumin ◽  
Low Concentrations ◽  
Colour Development ◽  
The Stability ◽  
Sodium And Potassium

We have evaluated a semi-quantitative dry immunochemical screening method (Micral-Test) for the detection of low concentrations of albumin in urine. The stability of Micral-Test strips on storage was good, especially with regard to temperature, light and humidity. Changes in urine osmolality (urea and creatinine concentration), pH and sodium and potassium concentration did not have a significant analytical effect on the Micral-Test measurement; extremes of temperature altered the rate of colour development. The depth of dipping the strip into the sample and the timing of reading colour development were critical. We measured the albumin concentration in 184 urine samples from diabetic outpatients by the Micral-Test and by our in-house immunoturbidimetric method; a Micral-Test result of 20 mg/L had a sensitivity of 91% and specificity of 97% to predict a discriminating urine albumin concentration > 30 mg/L by the in house method. The Micral-Test is suitable for use by non-laboratory personnel and is capable of producing analytically acceptable results for use in diabetes clinics and by general practitioners.

Influence of Composition, Concentration and Temperature of some Biological Liquids upon the Corrosion Behaviour of Titanum

2008 ◽  
Vol 59 (1) ◽  
pp. 17-24
Author(s):  
Rodica Popescu ◽  
Daniela Ionita ◽  
Florin Minculescu
Keyword(s):  
Lactic Acid ◽  
Body Temperature ◽  
Corrosion Behaviour ◽  
Passive Layer ◽  
Albumin Concentration ◽  
Cyclic Polarization ◽  
Low Concentrations ◽  
Human Body Temperature ◽  
Biological Liquids ◽  
The Stability

In order to investigate the corrosion behaviour of titan in aqueous solutions of lactic acid (1, 3 and 4% w) and albumin (2 and 10 % w) the cyclic polarization curves in potentiodynamic conditions were used. The corrosion parameters were estimated and their values were discussed as a function of acid lactic and albumin concentration and temperature. The stability of titan in investigated biological liquids was interpreted by involvment of the adsorption of either lactic acid or albumin onto the passive layer, a process which is favorised by moderate temperatures (as 370C � the human body temperature) as well as by low concentrations of lactic acid and albumin, respectively.

Kinetics of Various 99mTc-Sn-Pyrophosphate Compounds in the Rat

1977 ◽  
Vol 16 (04) ◽  
pp. 157-162 ◽  
Author(s):  
C. Schümichen ◽  
B. Mackenbrock ◽  
G. Hoffmann
Keyword(s):  
Normal Saline ◽  
Half Life ◽  
Compound A ◽  
Short Half Life ◽  
Low Concentrations ◽  
The Stability ◽  
Kinetics Of ◽  
In Vitro Stability

SummaryThe bone-seeking 99mTc-Sn-pyrophosphate compound (compound A) was diluted both in vitro and in vivo and proved to be unstable both in vitro and in vivo. However, stability was much better in vivo than in vitro and thus the in vitro stability of compound A after dilution in various mediums could be followed up by a consecutive evaluation of the in vivo distribution in the rat. After dilution in neutral normal saline compound A is metastable and after a short half-life it is transformed into the other 99mTc-Sn-pyrophosphate compound A is metastable and after a short half-life in bone but in the kidneys. After dilution in normal saline of low pH and in buffering solutions the stability of compound A is increased. In human plasma compound A is relatively stable but not in plasma water. When compound B is formed in a buffering solution, uptake in the kidneys and excretion in urine is lowered and blood concentration increased.It is assumed that the association of protons to compound A will increase its stability at low concentrations while that to compound B will lead to a strong protein bond in plasma. It is concluded that compound A will not be stable in vivo because of a lack of stability in the extravascular space, and that the protein bond in plasma will be a measure of its in vivo stability.

scholarly journals Prediction of renal dysfunction in patients with obstructive icterus

2011 ◽  
Vol 64 (9-10) ◽  
pp. 503-506 ◽  
Author(s):  
Suzana Raicevic-Sibinovic ◽  
Aleksandar Nagorni ◽  
Vesna Brzacki ◽  
Mirjana Radisavljevic
Keyword(s):  
Renal Function ◽  
Renal Dysfunction ◽  
Concentration Index ◽  
Surgical Intervention ◽  
Urine Osmolality ◽  
Sodium Concentration ◽  
Control Group ◽  
Osmotic Concentration ◽  
Creatinine Concentration ◽  
Urinary Osmolality

Introduction. Renal dysfunction is one of complications in patients with obstructive icterus. It is important to recognize it early and take adequate measure to prevent its occurrence. One third of the patients with obstructive icterus have deterioration of renal function before surgical intervention. The aim of the research was to assess the renal dysfunction markers in patients with obstructive icterus. The following factors were examined: diuresis, urinary sodium concentration, sodium excretory fraction, urine osmolality, osmotic concentration index, creatinine concentration index and renal index of lesion. Material and methods. The study included 85 patients with obstructive icterus (50 patients before surgical intervention and 35 after surgical intervention) and 30 patients without icterus as a control group. The patients with normal renal function before the development of the disease were included. Results. Malignant etiology was present in 39 patients and benign in 46 patients of the examined group. The evaluation parameters of renal function were examined in all of the patients. Creatinine concentration index led to the greatest change in the coefficient value of an internal consistency, showing that it was the best renal function marker in the examined group of patients with icterus. The next one was the urinary osmolality, since its exclusion would lead to a decrease in the value of Cronbach ? coefficient to 0.06. Icterus and surgical intervention show statistically significant effects to change in the value of the markers of laboratory differentiation of renal function, observed as an entire set. Discussion and conclusion. The examination showed that the concentration clearances of creatinine and urine osmolality are the parameters which point to the probability of renal dysfunction occurrence in obstructive icterus.

scholarly journals Effects of Maximal Sodium and Potassium Conductance on the Stability of Hodgkin-Huxley Model

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yue Zhang ◽  
Kuanquan Wang ◽  
Yongfeng Yuan ◽  
Dong Sui ◽  
Henggui Zhang
Keyword(s):  
Experimental Data ◽  
Mathematical Method ◽  
Bifurcation Point ◽  
Potassium Conductance ◽  
Maximal Conductance ◽  
Computing Model ◽  
The World ◽  
Stability And Bifurcations ◽  
The Stability ◽  
Sodium And Potassium

Hodgkin-Huxley (HH) equation is the first cell computing model in the world and pioneered the use of model to study electrophysiological problems. The model consists of four differential equations which are based on the experimental data of ion channels. Maximal conductance is an important characteristic of different channels. In this study, mathematical method is used to investigate the importance of maximal sodium conductanceg-Naand maximal potassium conductanceg-K. Applying stability theory, and takingg-Naandg-Kas variables, we analyze the stability and bifurcations of the model. Bifurcations are found when the variables change, and bifurcation points and boundary are also calculated. There is only one bifurcation point wheng-Nais the variable, while there are two points wheng-Kis variable. The (g-Na,  g-K) plane is partitioned into two regions and the upper bifurcation boundary is similar to a line when bothg-Naandg-Kare variables. Numerical simulations illustrate the validity of the analysis. The results obtained could be helpful in studying relevant diseases caused by maximal conductance anomaly.

scholarly journals Glutamate, calcium ion-chelating agents and the sodium and potassium ion contents of tissues from the brain

1970 ◽  
Vol 116 (2) ◽  
pp. 181-187 ◽  
Author(s):  
I. Pull ◽  
H. McIlwain ◽  
R. L. Ramsay
Keyword(s):  
Calcium Ion ◽  
Chelating Agents ◽  
Potassium Ion ◽  
Low Concentrations ◽  
Rate Of Increase ◽  
Other Substances ◽  
Ion Contents ◽  
Bicarbonate Solutions ◽  
The Brain ◽  
Sodium And Potassium

1. Salts of l-glutamate added to cerebral tissues maintained in glucose–saline–bicarbonate solutions cause the Na+ content of the tissues to increase rapidly and K+ to be lost. Entry of 22Na+ also is accelerated by l-glutamate and this acceleration is inhibited by low concentrations of tetrodotoxin. 2. Tissue Na+ content and its rate of increase after the addition of l-glutamate are affected by the Ca2+ of incubation media. 3. Very rapid and extensive entry of Na+ to the tissue is caused by EDTA, and a moderate entry by citrate and ATP. Calculations of the concentration of free Ca2+ in media after these additions indicate that Na+ entry is sometimes associated with low Ca2+ concentration, but that other substances, especially l-glutamate, act without greatly diminishing Ca2+ concentration. 4. Experiments with 2,4-dinitrophenol and valinomycin are also reported and aspects of the Na+ entry formulated and discussed.

scholarly journals Preparation of Isotopically Labelled Standards of Creatinine Via H/D Exchange and Their Application in Quantitative Analysis by LC-MS

Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1514
Author(s):  
Remigiusz Bąchor ◽  
Andrzej Konieczny ◽  
Zbigniew Szewczuk
Keyword(s):  
Internal Standard ◽  
Test Method ◽  
Simple Test ◽  
Liquid Chromatography Mass Spectrometry ◽  
Creatinine Concentration ◽  
Back Exchange ◽  
Acidic Conditions ◽  
Facile Preparation ◽  
The Stability ◽  
Neutral Conditions

Kidneys play a crucial role in maintaining metabolic homeostasis in a body. Serum creatinine concentration is a simple test used as an indicator of renal function. One of the known ways of quantifying creatinine concentration is the liquid chromatography-mass spectrometry (LC-MS) method, using an isotopically labeled analog of creatinine as an internal standard. Unfortunately, such isotope-labeled analogs are expensive and their synthesis is complex. Here we demonstrate a facile preparation of deuterated analogues of creatinine, via the H/D exchange of hydrogens located at the α-carbon (α-C) of the N-methylated amino acid part, under basic conditions. The stability of retrieved isotopologues was analyzed under both neutral or acidic conditions, and the results revealed that the introduced deuterons do not undergo back-exchange. In addition, the coelution of deuterated and non-deuterated forms under acidic and neutral conditions was observed. The prepared isotopologues were successfully applied in the quantitative LC-MS analysis of urine samples, and the results demonstrated that the presented strategy is novel and inexpensive, and that the quantification correlates with the commonly used Jaffe test method.

scholarly journals Accuracy Evaluation of a Tetrabromophenolphthalein Ethyl Ester Colorimetric Assay for Urinary Albumin

2019 ◽  
Vol 4 (2) ◽  
pp. 201-213
Author(s):  
Alyse D Krausz ◽  
Rajan Dewar ◽  
Mark A Burns
Keyword(s):  
Ethyl Ester ◽  
Colorimetric Assay ◽  
Point Of Care ◽  
Urinary Albumin ◽  
Urine Samples ◽  
Albumin Concentration ◽  
Accuracy Evaluation ◽  
Standard Samples ◽  
Creatinine Concentration ◽  
3D Surface

Abstract Background The tetrabromophenolphthalein ethyl ester (TBPE) assay has been used to quantify urinary albumin in point-of-care devices. We assessed the accuracy of this TBPE assay for urinary albumin through comparison with an established immunoturbidimetric method (ADVIA 1800 Chemistry System, Siemens). Methods We developed a TBPE assay protocol to quantify albumin in the range associated with microalbuminuria (0–200 mg/L). The Jaffe reaction and a 3-dimensional (3D) surface were used to compensate for creatinine interference. Spiked simulated urine samples and patient samples were used to compare the TBPE assay with the immunoturbidimetric method. Multiple linear regression was used to analyze factors that could account for discrepancies between the 2 methods. Results We found that creatinine interfered with the TBPE assay. To compensate, a 3D surface was successfully used to quantify albumin in spiked deionized water and simulated urine samples. In spiked simulated urine samples, the immunoturbidimetric method underestimated the albumin concentration by 2 to 45 mg/L, and the TBPE assay overestimated it by 9 to 82 mg/L. In patient samples, the albumin concentrations measured with the TBPE assay and the immunoturbidimetric method differed by an average of 184 mg/L. Conclusions The TBPE assay is a function of the creatinine concentration, and a 3D surface can be used to provide accurate albumin concentrations for standard samples. The corrected TBPE method and the immunoturbidimetric method deviated from known concentrations of spiked samples. Further investigation and comparisons with a third albumin measurement method, such as LC-MS/MS, are necessary before conclusions on the accuracy of the TBPE assay can be made.

Screening for microalbuminuria in patients with diabetes mellitus: frozen storage of urine samples decreases their albumin content.

1989 ◽  
Vol 35 (2) ◽  
pp. 308-310 ◽  
Author(s):  
L D Elving ◽  
J A Bakkeren ◽  
M J Jansen ◽  
C M de Kat Angelino ◽  
E de Nobel ◽  
...  
Keyword(s):  
Frozen Storage ◽  
Urine Samples ◽  
Diabetic Patients ◽  
Albumin Concentration ◽  
Low Concentrations ◽  
Albumin Content ◽  
Patients With Diabetes ◽  
The Difference ◽  
Urinary Albumin Concentration

Abstract The influence of storage on urinary albumin concentration was prospectively studied with use of overnight urine specimens (Albustix negative) from 73 diabetic patients. From each urine sample four aliquots were taken. One was stored at 4 degrees C and assayed within two weeks, the other three were stored at -20 degrees C and assayed within two weeks and after two and six months. Albumin concentration was measured with laser immunonephelometry. The detection limit, 1 mg/L, suffices for the screening of diabetic patients for microalbuminuria. After storage for two and six months at -20 degrees C, significantly lower albumin concentrations were found. The difference was mainly caused by lower concentrations found in urine samples in which a precipitate had formed, which was the case in 22 and 25 samples, respectively. Thus, freezing of urine samples for determination of low concentrations of albumin may yield falsely low results. Urine samples are best stored at 4 degrees C and assayed within two weeks.

Renal Sodium- and Potassium-Activated Adenosine Triphosphatase Deficiency During Post-obstructive Diuresis in the Rat

1974 ◽  
Vol 52 (1) ◽  
pp. 105-113 ◽  
Author(s):  
D. R. Wilson ◽  
W. Knox ◽  
E. Hall ◽  
A. K. Sen
Keyword(s):  
Atpase Activity ◽  
Adenosine Triphosphatase ◽  
Filtration Rate ◽  
Renal Cortex ◽  
Urine Osmolality ◽  
Tubular Reabsorption ◽  
Enzyme Analysis ◽  
Outer Medulla ◽  
Sodium Load ◽  
Sodium And Potassium

Renal function studies and tissue enzyme analysis were carried out in rats with bilateral ureteral ligation (24 h) and after relief of obstruction at intervals of 2 h, 24 h, 3 days, and 7 days. A persistent decrease in glomerular filtration rate and in tubular reabsorption of sodium, solute, and water was noted at each interval after relief of obstruction. Renal sodium- and potassium-activated adenosine triphosphatase (Na–K-ATPase) activity was unchanged in kidneys obstructed for 24 h, but enzyme activity was decreased in the outer medulla of the kidney and, less often, in the renal cortex, at each interval studied during the post-obstructive period. Magnesium-dependent adenosine triphosphatase (Mg-ATPase) activity was not changed in any of the groups. In the post-obstructive kidney (24 h, 3 days, and 7 days) there was a significant correlation between the decrease in outer medullary Na–K-ATPase activity and the changes in filtered sodium load, tubular reabsorption of sodium, and urine osmolality. A deficiency of renal Na–K-ATPase could be important in the pathogenesis of post-obstructive natriuresis and diuresis.

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