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PubMed1993

D-lysine reduces the non-enzymatic glycation of proteins in experimental diabetes mellitus in rats.

D-Lysine, the non-physiological isomer of L-lysine, can competitively reduce protein non-enzymatic glycation in vitro. To study the effect of D-lysine in vivo, 6-8-week old Sprague-Dawley rats with streptozotocin-induced diabetes mellitus were treated from diagnosis for 45 days with two daily subcutaneous injections of D-lysine (0.5 g.ml-1.day-1). Another group of diabetic rats was only injected with equal volumes of physiological saline (0.9% NaCl). Glycated haemoglobin was measured by ion exchange chromatography, and glycated serum and lens proteins by boronate affinity gel chromatography. Serum and urinary creatinine concentrations were evaluated by the alkaline-picrate reaction. Urinary lysine concentrations at mid- and end-study were evaluated by cation exchange chromatography. Blood glucose concentrations, serum creatinine levels and creatinine clearances, measured at the end of the study, were similar in both diabetic groups (> 22.0 mmol/l, < or = 106 mumol/l and approximately 0.02 ml/s, respectively). Urinary lysine concentration in D-lysine-treated diabetic animals was more than 50-fold higher than in placebo-treated diabetic rats. In D-lysine-treated vs placebo-treated diabetic animals, a statistically significant reduction was found in the levels of glycated haemoglobin (stable HbA1; mean +/- SD = 3.00 +/- 0.74% vs 4.02 +/- 0.46%, p < 0.05; labile HbA1 = 3.92 +/- 0.89% vs 5.84 +/- 0.61%, p < 0.005), glycated serum proteins (1.40 +/- 0.47% vs 2.52 +/- 1.15%, p < 0.05) and glycated lens proteins (4.90 +/- 0.96% vs 5.98 +/- 0.65%, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1987

Effect of amiloride on bulk flow and iontophoretic taste stimuli in the hamster.

This investigation demonstrates the effect of amiloride on various taste responses in the hamster, and tests the hypothesis that its action on iontophoretic application of taste stimuli parallels its action on bulk flow delivery. Amiloride has not previously been tested in the hamster nor has its effect on iontophoretic stimuli (so-called 'electric taste'), which is thought to behave similarly to bulk flow stimuli, been examined. Amiloride treatment (4 min of 0.0001 M) of the hamster's tongue effectively inhibited chorda tympani responses to NaCl and LiCl solutions. Bulk flow (0.1 M) and iontophoretic (+ 7 microA through 0.001 M) presentations of NaCl and LiCl, which had unequal response magnitudes pre-treatment, were inhibited to the same residual response magnitude post-treatment. Recovery then proceeded along two distinct curves asymptotically returning to pre-treatment response levels. These curves could be adequately described by a simple exponential relationship. KCl responses were unaffected when presented via bulk flow techniques but significantly reduced when presented iontophoretically. HCl responses via either method were only slightly diminished. No decrement in response level was observed for the sweet stimuli sucrose (0.5 M) or saccharin (-9 microA through 0.001 M Na-saccharin) nor for potassium picrate, a bitter stimulus, (0.01 M or -10 microA through 0.001 M). Amiloride treatment of the hamster tongue was as specific in its action for sodium and lithium as reported in other species, and with the exception of KCl the action of amiloride on iontophoretic stimulation paralleled its action on bulk flow stimulation.

Amiloride↗

PubMed1978

Transport of organic anions through the erythrocyte membrane as K+-valinomycin complexes.

K+, Rb+, or Cs+ complexes of valinomycin form ion pair complexes with picric acid and trinitrobenzenesulfonate (TNBS). The formation of a picrate-K+-valinomycin complex is supported by spectral evidence. These complexes have zero net charge and readily permeate the intact erythrocyte membrane. The K+-valinomycin complex has been used to convert the nonpenetrating TNBS into a penetrating covalent probe, making it as useful vectorial probe to measure accessible amino groups of proteins and phospholipids on both sites of the erythrocyte membrane. The enhanced transport of TNBS into the cell by valinomycin is dependent on external K+ in the medium. The entry of TNBS into the cell is manifested by an increased labeling of hemoglobin and membrane phosphatidylethanolamine (PE). Stilbeneisothiocyanatedisulfonate (SITS) and anilinonaphthalenesulfonate (ANS) inhibit both the basal and K+-valinomycin stimulated labeling of PE and hemoglobin by TNBS. The data suggest two independent effects of ANS and SITS, one mediated by an inhibition of the anion transport protein and another by the incorporation of these hydrobic anions into the cell membrane with an increase in negative charge on the membrane which leads to an inhibition of TNBS permeation into the cell by electrostatic repulsion.

Anilino Naphthalenesulfonates↗

PubMed2005

Prediction of two-sample (99m)Tc-diethylene triamine pentaacetic acid plasma clearance from single-sample method.

OBJECTIVES: To develop an equation to predict dual plasma sample method (DPSM) (99m)Tc-diethylene triamine pentaacetic acid ((99m)Tc-DTPA) plasma clearance from single plasma sample method (SPSM), and to clarify the condition in which DPSM can be substituted by SPSM in measurement of glomerular filtration rate (GFR). METHODS: Patients with chronic kidney disease (CKD) were selected. Watson modified Christensen and Groth equation was used to calculate (99m)Tc-DTPA plasma clearance by SPSM (sGFR). The equation recommended by the Nephrourology Committee of the Society of Nuclear Medicine was used to calculate (99m)Tc-DTPA plasma clearance by DPSM (tGFR) in each patient. The difference between sGFR and tGFR was expressed as percent of the average of these two methods, and tGFR was predicted from sGFR. Plasma creatinine was measured by the kinetic picrate method, and GFR estimated by abbreviated modification of diet in renal disease (MDRD) equation (aGFR) and Cockcroft-Gault equation (cGFR) were evaluated as criteria in selection of DPSM and SPSM. RESULTS: Three hundred and sixty-nine patients with CKD were selected (208 male and 161 female). The average age and body weight were 51.4 +/- 15.5 years and 67.2 +/- 12.5 kg, respectively. The causes of CKD were glomerular disease, renal arterial stenosis, chronic tubulointerstitial disease, and other causes or causes unknown. The average tGFR was 62.9 +/- 36.5 ml/min/1.73 m2, ranging from 1-180 ml/min/1.73 m2. sGFR was significantly correlated with tGFR (r = 0.9194, p < 0.001), but widely scattered when tGFR <30 ml/min/1.73 m2; in contrast, then tGFR was > or =30 ml/min/1.73 m2, the difference was constant (-1.1%, 95% confidence interval -18.3%, 16.1%), and tGFR could be predicted from sGFR using the equation: predicted tGFR (ml/min/1.73 m2) = 7.4244 + 0.7318 x sGFR + 0.0022 x sGFR2 (n = 299, r2 = 0.9428, p < 0.001), and the difference decreased to 0.1%, 95% confidence interval (-15.8%, 16.0%). aGFR was better than cGFR in diagnosis of tGFR <30 ml/min/1.73 m2, the diagnostic sensitivity of a cut off value of aGFR = 45 ml/min/1.73 m2 was 91.8%, and recommended as a criterion in the selection of DPSM and SPSM. CONCLUSION: When GFR > or =30 ml/min/1.73 m2, tGFR can be predicted from sGFR, which will simplify the reference GFR measurement in clinical trials. sGFR becomes widely scattered when tGFR is less than 30 ml/min/1.73 m2. To obtain reliable reference GFR values, it is recommended that DPSM be used in clinical trials when aGFR is less than 45 ml/min/1.73 m2.

Algorithms↗

PubMed2004

Determination of ion-pair formation constants of univalent metal-crown ether complex ions with anions in water using ion-selective electrodes: application of modified determination methods to several salts.

Ion-pair formation constants (mol(-1) dm3 unit), K(MX) for a univalent metal salt (MX) and K(MLX) for its ion-pair complex (ML+X-) with a crown ether (L) in water, were determined at various ionic strengths (I) and 25 degrees C by potentiometry with ion-selective electrodes for MX=NaPic, NaMnO4, NaBPh4, KPic, and KMnO4; and MLX = Na(18C6)Pic, K(18C6)Pic, and Na(18C6)BPh4, where Pic- and 18C6 denote a picrate ion and 18-crown-6 ether, respectively. Equations for analyzing I-dependence of logK(MLX) and logK(MX) were derived and fitted well to the I-dependence using a non-linear regression analysis. The equilibrium constants at I = 0 mol dm(-3), K(MLX) degrees and K(MX) degrees, were simultaneously obtained from the analysis. The experimental values of K(MLX) and K(MX) were only in agreement with the values calculated from K(MLX) degrees and K(MX) degrees , respectively, in the ranges of higher I.

Journal Article↗

PubMed2005

Transport properties and electroanalytical response characteristics of drotaverine ion-selective sensors.

The construction and electroanalytical response characteristics of poly(vinyl chloride) matrix ion-selective sensors (ISSs) for drotaverine hydrochloride are described. The membranes incorporate ion-association complexes of drotaverine with tetraphenylborate, picrate, tetraiodomercurate, tetraiodobismuthate, Reinecke salt, and heteropolycompounds of Keggin structure-molybdophosphoric acid, tungstophosphoric acid, molybdosiliconic acid and tungstosiliconic acid as electroactive materials for ionometric sensor controls. These ISSs have a linear response to drotaverine hydrochloride over the range 8 x 10(-6) to 5 x 10(-2) mol L(-1) with cationic slopes from 51 to 58 mV per concentration decade. These ISSs have a fast response time (up to 1 min), a low determination limit (down to 4.3 x 10(-6) mol L(-1)), good stability (3-5 weeks), and reasonable selectivity. Permeabilities and ion fluxes through a membrane were calculated for major and interfering ions. Dependences of the transport properties of the membranes on the concentrations of the ion exchanger and near-membrane solution and their electrochemical characteristics are presented. The ISSs were used for direct potentiometry and potentiometric titration (sodium tetraphenylborate) of drotaverine hydrochloride. Results with mean accuracy of 99.1+/-1.0% of nominal were obtained which corresponded well to data obtained by use of high-performance liquid chromatography.

Calibration↗

PubMed1988

Immobilization of linamarase and its use in the determination of bound cyanide in cassava using flow injection analysis.

Extracts from the tubers (cortex and parenchyma) and leaves of Manihot esculenta Crantz (cassava) were analyzed for their releasable cyanide content using flow injection analysis incorporating an immobilized linamarase bioreactor. Linamarase was immobilized under very mild conditions to an activated 2-fluoro-N-methylpyridinium Fractogel support. The released cyanide, which was monitored spectrophotometrically at 525 nm using an alkaline picrate reagent, was found to be highest in the cortex and lowest in the parenchyma.

Calibration↗

PubMed1976

A new method for the determination of serum creatinine based on reaction with 3.5-dinitrobenzoyl chloride in an organic medium.

A new method for the determination of serum creatine, based on its reaction with 3,5-dinitrobenzoyl chloride in an organic medium is described. Various analytical parameters are studied and comparisons are made with the routine picrate procedures, as well as the dinitrobenzoic acid methods reported in the literature. On the basis of the data submitted, the proposed method is recommended for routine clinical use.

Colorimetry↗

PubMed1978

A new automated method for the determination of true creatinine in serum by means of the centrifichem centrifugal analyzer, based on Slot's principle; with special reference to low substrate concentrations.

A new automated method is proposed for the accurate determination of the true creatinine concentration in 20 microliter serum, based on the measurement of the initial rate of the decomposition reaction of the creatinine picrate complex caused by decreasing the pH. The results of this method, performed with a Centrifichem centrifugal analyzer system (type 300 F), are compared with the results obtained by two other methods: a manual method based upon the adsorption on Fuller's earth, and the Auto Analyzer method. In these comparative studies special attention is paid to the analysis of sera containing low (normal) substrate concentrations. Calculation of the orthogonal regression between the results obtained by the adsorption method (x) and the proposed method (y) gave: y=0.97x +/- 5 mumol/l (x=91.3 mumol/l, y-93.5 mumol/l), while for the correlation coefficient (r) 0.9721 was found. All sera (n=113) had creatinine concentrations between 40 and 180 mumol/l.

Centrifugation↗

PubMed1987

Characterization of GABAA receptor-mediated 36chloride uptake in rat brain synaptoneurosomes.

gamma-Aminobutyric acid (GABA) receptor-mediated 36chloride (36Cl-) uptake was measured in synaptoneurosomes from rat brain. GABA and GABA agonists stimulated 36Cl- uptake in a concentration-dependent manner with the following order of potency: Muscimol greater than GABA greater than piperidine-4-sulfonic acid (P4S)greater than 4,5,6,7-tetrahydroisoxazolo-[5,4-c]pyridin-3-ol (THIP) = 3-aminopropanesulfonic acid (3APS) much greater than taurine. Both P4S and 3APS behaved as partial agonists, while the GABAB agonist, baclofen, was ineffective. The response to muscimol was inhibited by bicuculline and picrotoxin in a mixed competitive/non-competitive manner. Other inhibitors of GABA receptor-opened channels or non-neuronal anion channels such as penicillin, picrate, furosemide and disulfonic acid stilbenes also inhibited the response to muscimol. A regional variation in muscimol-stimulated 36Cl- uptake was observed; the largest responses were observed in the cerebral cortex, cerebellum and hippocampus, moderate responses were obtained in the striatum and hypothalamus and the smallest response was observed in the pons-medulla. GABA receptor-mediated 36Cl- uptake was also dependent on the anion present in the media. The muscimol response varied in media containing the following anions: Br- greater than Cl- greater than or equal to NO3- greater than I- greater than or equal to SCN- much greater than C3H5OO- greater than or equal to ClO4- greater than F-, consistent with the relative anion permeability through GABA receptor-gated anion channels and the enhancement of convulsant binding to the GABA receptor-gated Cl- channel.

Animals↗

PubMed1993

Microdiffusion method with solid state detection of cyanogenic glycosides from cassava in human urine.

A method for quantitative determination of cyanogenic glycosides in human urine is described. It is based on enzymatic cleavage of the glycosides, microdiffusion of the hydrogen cyanide formed, solid state detection by colour formation on a picrate-impregnated sheet, and subsequent rating of the coloured spot by the absorption of transmitted light at 540 nm with a thin-layer (TLC) densitometer. The method has been tested using normal as well as pathological urines containing glucose, protein, leucocytes, blood and bacteria. The method allows quantification of urinary linamarin above 70 mumol/litre, in 40 microliters urine. In Mozambican subjects consuming insufficiently processed cassava the mean urinary linamarin levels were 211 mumol/litre, indicating for the first time that substantial amounts of the main cyanogenic glycoside in cassava may be absorbed from the human gut and excreted intact in the urine.

Administration, Oral↗

PubMed1986

The use of an enzymatic kit to measure plasma creatinine in the mouse and three other species.

Plasma creatinine concentrations were determined in mice, rats, dogs and humans using a kinetic alkaline picrate method and an enzymatic method with a centrifugal analyser. Lower creatinine values were obtained for all four species using the enzymatic method, but the differences between methods were greater for mice and rats. Removal of creatininase from the enzymatic method reagents gave proportionally higher values for non-creatinine chromogens in mice and rats. A single enzymatic method was not specific for creatinine when used for these species.

Amidohydrolases↗

PubMed1988

Radioreceptor assays of ipratropium bromide in plasma and urine.

Ipratropium bromide (Ipbr) is a frequently used quaternary anticholinergic administered by inhalation in the treatment of chronic obstructive lung diseases. Hardly any pharmacokinetic data are available, which can be useful in the optimisation of anticholinergic therapies. Hence, a radioreceptor assay (RRA) for Ipbr has been developed. The RRA is based on the competition between (3)H-N-methylscopolamine chloride ((3)H-NMS) and Ipbr for binding to lyophilised muscarinic receptors from calf brains. The assay has been optimised in respect of incubation conditions and extraction by ion-pair formation with sodium picrate. Detection limits of the drug were 5 ng ml(-1) in urine and 500 pg ml(-1) in plasma, after extraction of 2-ml samples. The method is applicable to monitoring the drug in plasma and urine after therapeutic dosing.

Journal Article↗

PubMed2004

Studies on 1H NMR, infrared and fluorescence spectra of rare earth complexes with a new binaphthylamide.

Solid complexes of lanthanide picrates with N,N-dibenzyl-2-[2'-[(dibenzylcarbamoyl)-methoxy]-[1,1']binaphthalenyl-2-yloxy]-acetamide (L), [Ln(pic)(3)L] (Ln = La, Nd, Eu, Gd, Tb, Dy, Y), have been prepared and characterized by elemental analysis, IR, 1H NMR, UV-Vis spectra and conductivity measurements. The fluorescence property of the europium complex in solid state and in CHCl(3), acetone, AcOEt and DMF was studied.

Acetamides↗

PubMed2006

Synthesis and infrared and fluorescence spectra of rare earth complexes with a novel amide-based ligand.

A novel amide-based open-chain crown ether, N,N'-1,3-propanediyl-bis[2-(benzyl -carbamoyl-methoxy)-benzamide] (L) and its solid complexes with rare earth nitrates and picrates have been prepared. The complexes were characterized by elemental analyses, molar conductivity and IR spectra. The fluorescence properties of the Eu(III) and Tb(III) complexes in solid and in organic solvents were studied. Under the excitation of ultraviolet light, these complexes exhibit characteristic emission of europium and terbium ions. The results show that the ligand favor energy transfers to the emitting energy level of Tb(III). Some factors that influence the fluorescent intensity were also discussed.

Amides↗

PubMed2007

Linamarase activities in Bacillus spp. responsible for thermophilic aerobic digestion of agricultural wastes for animal nutrition.

Thermophilic Bacillus spp. isolated from thermophilic aerobic digestion (TAD) of model agricultural slurry were screened for ability to secret linamarase activity and degrade linamarin, a cyanogenic glycoside toxin abundant in cassava. Screening was performed by both linamarin - picrate assay and by p-nitrophenyl beta-D-glucoside (PNPG) degradation, and results of both assays were related. Linamarase positive isolates were identified as Bacillus coagulans, Bacillus licheniformis and Bacillus stearothermophilus. Enzyme production was growth related and peak production was reached in 48 h in B. coagulans and 36 h in B. stearothermophilus. B. coagulans produced over 40 times greater activity than B. stearothermophilus. Enzyme productivity in shake flask was not strictly related to screening assay result. Crude enzyme of B. coagulans was optimally active at 75 degrees C while that of B. stearothermophilus was optimally active at 80 degrees C and both had optimum activity at pH 8.0. The thermophilic and neutrophilic- to marginally alkaline activity of the crude enzymes could be very useful in the detoxification and reprocessing of cyanogens containing cassava wastes by TAD for use in animal nutrition.

Aerobiosis↗

PubMed1980

Comparison of plasma creatinine determined with the Greiner Selective Analyser GSA II and the glomerular filtration rate.

1. Reference values for the plasma creatinine were established using the alkaline picrate method with the Greiner Selective Analyzer GSA II in relation to the Cr 51-EDTA Clearance. Individuals with normal GFR between 93 to 159 ml/min/1.73 m2 had creatinine values in men (n = 65) from 53.7 to 119.5 mumol/l (0.61 to 1.35 mg/100 ml) and in women (n = 59) from 37.7 to 107 mumol/l (0.42 to 121 mg/100 ml). 2. The creatine determinations with the GSA II were compared to those on the Technicon Analyzer, the Beckman Creatinine Analyzer, the Gemsaec-Fast Analyzer and to the enzymatic creatinine method. A good correlation (r = 0.9780-0.984) was observed. 3. With the GSA II and the enzymatic method, bilirubin showed a minor interference which was more marked with the Beckman analyzer.

Adolescent↗

PubMed1991

Urinary porphyrin excretion in normal children and adults.

The relationship of random urinary porphyrin and creatinine values as functions of age and sex was examined in a normal population. Total urinary porphyrin was measured by a solvent extraction technique, while urinary creatinine was evaluated by an alkaline picrate method. Random urine specimens from 120 healthy patients (81 children and 39 adults) were evaluated. In both pediatric and adult populations, a strong correlation was found between urinary concentrations of porphyrin and creatinine (r = 0.7, P less than 0.0001). Urinary porphyrin excretion in mumol/mol creatinine (micrograms/g) was inversely related to both age (r = -0.59, P less than 0.0001) and weight (r = -0.61, P less than 0.0001) until approximately 9 years of age or 30 kg. Urinary porphyrin excretion in children 9 to 18 years of age was lower than that of younger children (P less than 0.0001) and approached adult values. Sex was not found to be a factor until 9 to 18 years of age, when females had higher urinary creatinine concentrations (P less than 0.05), but lower urinary porphyrin excretions (P less than 0.05) than similarly aged males. The converse was observed when similar values of adult women were compared with those of adult men. Men also had higher urinary porphyrin concentrations than women (P less than 0.01). Men had increased urinary creatinine concentration (P less than 0.05) and decreased porphyrin excretion ratios (P less than 0.05) when compared with males 9 to 18 years of age. Women had significantly lower urinary creatinine (P less than 0.001) and porphyrin (P less than 0.001) concentrations than females 9 to 18 years of age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗