Comparison of the effects of low intra-abdominal pressure and pentoxifylline on oxidative stress during CO2 pneumoperitoneum in rabbits.

BACKGROUND: The aim of this study was to investigate the effect of low-pressure pneumoperitoneum and pentoxifylline, a methylxanthine derivative, in the prevention of injury caused by free oxygen radicals generated during CO(2 )pneumoperitoneum. METHODS: Twenty-eight rabbits were allocated randomly to 4 groups. Control group rabbits (group 1) were subjected to anesthesia for 60 min; group 2 and 3 animals were subjected to a CO(2) pneumoperitoneum (15 or 7 mm Hg); and group 4 rabbits received 50 mg/kg pentoxifylline, followed by a 15-mm-Hg pneumoperitoneum. Serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH), lipid hydroperoxide, glutathione reductase and total antioxidant status were measured. RESULTS: Compared with group 1, a significant increase in lipid hydroperoxide levels at the end of the pneumoperitoneum and 30 min after deflation and a significant decrease in total antioxidant status 24 h after deflation were recorded in group 2. In addition, a significant increase was observed in ALT, AST and LDH levels. These changes were attenuated by low-pressure pneumoperitoneum, whereas pentoxifylline pretreatment appeared to attenuate only transaminase levels. CONCLUSION: Low-pressure pneumoperitoneum could attenuate ischemia/reperfusion injury induced by CO(2 )pneumoperitoneum in a rabbit model whereas pentoxifylline pretreatment appeared to attenuate only transaminase levels. Pentoxifylline did not prevent the development of oxidative stress.

COPD: magnesium in the plasma and polymorphonuclear cells of patients during a stable phase.

Magnesium is one of the most important factors for regulation of inflammatory response as well as muscle function, and COPD is a multicomponent disease characterized by abnormal inflammatory response of the lungs with systemic muscle dysfunction. Because polymorphonuclear (PMN) cells are significantly represented in the pathogenesis of COPD, concentrations of total (tMg) and ionised magnesium (iMg) were determined in plasma and isolated PMN cells in 46 patients in stable phase of COPD (past smokers, current smokers, and non-smokers), 24 healthy smokers and 37 healthy non-smokers. In the same samples concentrations of total (tCa) and ionised calcium (iCa) were determined, due to the antagonism of magnesium towards calcium. We found decreased biological active iMg in PMN compared to the group of healthy non-smokers (5.42, 1.98-17.31 micromol/10(9) cells vs. 7.50, 3.27-15.15 micromol/10(9) cells, p < 0.05). In the plasma and isolated PMN of the patients the ratio of total calcium/total magnesium (tCa/tMg) was significantly increased (2.89, 2.15-3.86 and 1.19, 0.07-9.87) compared to the group of healthy non-smokers (2.65, 2.19-3.44 and 0.67, 0.14-2.40, p < 0.05) and to the group of healthy smokers (2.58, 2.26-3.24 and 0.66, 0.14-2.85, p < 0.05). In the group of patients the concentration of tCa was significantly increased in all samples compared to the healthy group of non-smokers and healthy smokers. The results of univariant logistic regression analysis for smoking, concentration of tCa and ratio of tCa/tMg in PMN showed high odds ratio for COPD status. These results raise a possibility that intracellular polymorphonuclear value of magnesium could be a distinctive marker for COPD risk disclosure among smokers.

Use of a ruthenium(III), iron(II), and nickel(II) hexacyanometallate-modified graphite electrode with immobilized oxalate oxidase for the determination of urinary oxalate.

This paper describes the performance of a biosensor with an Ru(III), Ni(II), and Fe(II) hexacyanometallate-modified graphite electrode and immobilized oxalate oxidase for the determination of urinary oxalate. The addition of ruthenium enhances the electrochemical reversibility and chemical stability of the electrocrystallized layer and improves the sensitivity of the biosensor. Hydrogen peroxide, produced by the enzyme-catalyzed oxidation of oxalate, was measured at -50 mV vs an Hg Hg2CI2 3M KCl electrode in a solution of pH 3.6 succinic buffer, 0.1 M KCl, and 5.4mM ethylenediaminetetraacetic acid. The linear concentration range for the determination of oxalate was 0.18-280 microM. The recoveries of added oxalate (10-35 microM) from aqueous solution ranged from 99.5 to 101.7%, whereas from urine samples without oxalate (or with a concentration of oxalate below the detection limit) the recoveries of added oxalate ranged from 91.4 to 106.6%. The oxalate in 24 h urine samples, taken during their daily routine from 35 infants and children, was measured and found to range from 0.6 to 121.7 mg/L. There were no interferences from uric acid, acetylsalicylic acid, and urea in the concentration range investigated, but paracetamol and ascorbic acid did interfere. A good correlation (R2 = 0.9242) was found between values obtained for oxalate in real urine samples by 2 laboratories, with the proposed biosensor and ion chromatography, respectively.

Determination of oxalate in urine, using an amperometric biosensor with oxalate oxidase immobilized on the surface of a chromium hexacyanoferrate-modified graphite electrode.

A novel enzymatic amperometric method is described for the determination of oxalic acid in urine. An amperometric biosensor was made by immobilizing oxalate oxidase on the surface of a chromium(III) hexacyanoferrate-modified graphite electrode by using a bovine serum albumin and glutaraldehyde cross-linking procedure. The enzyme biocatalyzes oxalate decomposition in the presence of oxygen into carbon dioxide and hydrogen peroxide. The oxalate concentration, which is proportional to the amount of hydrogen peroxide, was determined amperometrically by measuring the current resulting in the reduction of hydrogen peroxide at a very low working potential (0.05 V versus the Hg ¿Hg2Cl2¿ 3M KCl electrode), which minimized the influence of the possible interferences present in human urine. All experiments were performed with succinic buffer, pH 3.8, containing 0.1M KCl and 5.4mM ethylenediaminetetraacetic acid. In an aqueous solution of pure oxalic acid, the biosensor showed good linearity in a concentration range of 2.5-100 microM without the use of a dialysis membrane. For untreated urine samples, a high correlation (R2 = 0.9949) was obtained between oxalate concentrations added to urine samples and oxalate recoveries calculated for determinations with the described oxalate biosensor.

Clinical value of biochemical markers in the diagnosis of acute myocardial infarction.

Current strategy for the use of biochemical markers in the diagnosis of acute myocardial infarction is not yet uniform. New markers of myocardial damage have significantly altered the former viewpoints. The study included 41 patients with confirmed acute myocardial infarction (25 males and 16 females, age range 42-85 years). Control group comprised of 25 patients with chronic renal failure without signs of acute coronary event (n = 11) and patients with confirmed coronary artery disease (n = 14). The level and activity of CKMB (microgram/L and U/L), and the level of myoglobin and cTnl were determined. The results showed the sensitivity of CKMB (microgram/L) in the first six hours from the onset of pain to be statistically significantly higher than the sensitivity of cTnl, while myoglobin was confirmed to be the earliest marker. Determination of CKMB (U/L) activity should be abandoned since it was found to have the lowest sensitivity and specificity. Also, a combination of myoglobin and CKMB (microgram/L) showed a statistically significantly higher sensitivity and diagnostic efficacy but lower diagnostic specificity compared to the combination of myoglobin and cTnl.

Assessment of difference between calculated and measured blood hydrogen carbonate concentration by anion gap.

Differences between calculated and measured hydrogen carbonate concentrations can pose a serious problem not only in monitoring severely ill patients, but also in those on hemodialysis. The purpose of this study was to investigate the possibility of estimation of differences between the calculated and measured hydrogen carbonate concentration by anion gap. The study included patients from regular hemodialysis program, and from Departments of Surgery, of Neurology and of Internal Medicine. Our results showed a 16% difference between measured and calculated hydrogen carbonate. Anion gap is a very useful parameter in assessing electrolyte disturbances. The discrepancy between the measured and calculated hydrogen carbonate concentration also increased with the rise in anion gap. Our results showed the possibility to determine the level of concentration difference by anion gap. This could be useful in situations such as metabolic acidosis, characterised by striking changes in electrolyte concentrations.

Distribution of human erythrocyte acetylcholinesterase according to age, sex and pregnancy.

The distribution of erythrocyte acethylcholinesterase (AChE, EC 3. 1. 1. 7.) activity according to age, sex and pregnancy is described. Study population included 260 subjects: 117 men and 111 women, aged 0 to 70 years, and 32 pregnant women aged 20 to 40 years. The study showed no significant differences in RBC-AChE activity either between males and females or between various age groups. A statistically significantly elevated RBC-AChE activity was however, recorded in pregnant women.

Determination of urine saturation with computer program EQUIL 2 as a method for estimation of the risk of urolithiasis.

To investigate the risk for the development of urolithiasis in 30 children with urolithiasis, 36 children with isolated hematuria, and 15 healthy control children, 24-h urinary excretion of calcium, sodium, oxalate, citrate, sulfate, phosphate, magnesium, urate, chloride, ammonium, and glycosaminoglycans was determined and urine saturation for calcium oxalate was calculated with the computer program EQUIL 2. Compared with controls, children with urolithiasis had significantly increased calcium excretion, oxalate excretion, and urine saturation, whereas children with isolated hematuria had significantly increased calcium excretion only. The best estimation of the relative risk of urolithiasis can be made after urine saturation, using logistic regression. The percentage of patients correctly classified after urine saturation is 85.41% in comparison with 80.95% and 73.81% when the estimation was done by calcium excretion and oxalate excretion, respectively. Using the breakpoint value of 4.29 for urine saturation, it was possible to separate children with increased risk of urolithiasis development from the group of children with isolated hematuria.

[Assessement of clinical applicability of acute myocardial infarction markers]. / Procjena klinicke uporabljivosti biljega akutnog infarkta miokarda.

This study was conducted in order to compare sensitivity of AMI markers and to establish the optimal combination of markers of AMI, thus allowing as early application of therapy as possible. In this study we investigated 18 patients (5 women and 13 men) of different ages. There is a difference in early sensitivities ofAMI markers; < or =2 hours after the onset of chest pain myoglobin and troponin T showed greater sensitivity than CK and CKMB. None of the tested markers had the sensitivity greater than 80% before 2-5 hours after the onset of chest pain. The study demonstrated that differences in sensitivities of AMI markers 2-5 hours after the onset of chest pain were slight and are not deemed to be clinically relevant. In the same group relative increase in myoglobin was only transiently higher. High sensitivity of troponin T retained during 10 days also allows the use of this marker in case of late admission of a patient. Therefore, turnaround time and practicality in emergency determination, specificities of these markers, and costs will mainly determine the choice of AMI markers.

[The Q.E.D. test--possibility for rapid determination of ethanol levels in saliva]. / Q.E.D. test--mogucnost brzog odredivanja koncentracije etanola u slini.

The present study has been undertaken to compare the Q.E.D. test, a quantitative enzymatic method for the determination of ethanol concentration in the saliva, and quantitative methods for determination of ethanol serum concentrations: UV alcohol dehydrogenase method and gas chromatography. The results of the study demonstrated a statistically significant correlation between the methods compared. We conclude that Q.E.D. test is an effective, rapid and safe method for specific quantitative determination of ethanol levels in the blood defined by ethanol concentrations in the saliva, especially in outpatient departments, initial emergency treatment as well as in differential diagnosis. Sometimes, an increased salivary viscosity caused by dehydration of an acutely drunken man as well as insufficient cooperation of the examinee may, however, aggravate the test performance. We propose the use of a test that measures ethanol concentration in the saliva up to 3.5 g/L in order to avoid repetition of the test.

Chlorpyrifos metabolites in serum and urine of poisoned persons.

Concentrations of parent pesticide and corresponding diethylphosphorus metabolites in blood serum and urine were investigated in persons who had ingested a concentrated solution of organophosphorus pesticide chlorpyrifos. The organophosphate poisoning was indicated by a significant depression of blood cholinesterase (EC 3.1.1.7 and EC 3.1.1.8) activities. Blood and spot urine samples were collected daily after admission of the persons to hospital. Chlorpyrifos was detected only in serum samples in a period up to 15 days after poisoning. In the same samples chlorpyrifos oxygen analogue, chlorpyrifos oxon, was not detected. The presence of diethylphosphorothioate in all serum and urine samples confirmed that part of chlorpyrifos was hydrolysed before its oxidation. The maximum concentrations of chlorpyrifos in serum and of metabolites in serum and urine were measured on the day of admission. The decrease in concentrations followed the first-order kinetics with the initial rate constant faster and the later one slower. In the faster elimination phase chlorpyrifos was eliminated from serum twice as fast (t1/2 = 1.1-3.3 h) as the total diethylphosphorus metabolites (t1/2 = 2.2-5.5 h). The total urinary diethylphosphorus metabolites in six chlorpyrifos poisoned persons were excreted with an average elimination half-time of 6.10 +/- 2.25 h (mean +/- S.D.) in the faster and of 80.35 +/- 25.8 h in the slower elimination phase.

Diethylphosphorus metabolites in serum and urine of persons poisoned by phosalone.

The presence and elimination rate of phosalone and its diethylphosphorus metabolites in blood serum and urine were studied in persons who had ingested a concentrated phosalone solution. Phosalone was detected only in serum samples. As it was rapidly hydrolysed and eliminated from the body, its diethylphosphorus metabolites were a more sensitive indicator of exposure. The concentration decrease of phosalone in serum and of total diethylphosphorus metabolites in serum and urine followed the kinetics of a biphasic reaction. The faster elimination half-times in serum, calculated for two persons, were 2.3 and 3.4 h for phosalone and 3.4 and 38.6 h for total diethylphosphorus metabolites. In the faster phase the average elimination half-time of total urinary metabolites in five persons was 25 +/- 17 h. The kinetic data for total urinary metabolites in a person occupationally exposed to phosalone indicated an early and very fast elimination phase (elimination half-time 1.3 h), which was overlooked in poisoned persons. The proportions of single metabolites in total urinary metabolites in poisoned persons depended on whether the total amount of diethylphosphorus metabolites was above 1000 or below 1000 nmol/mg creatinine. Diethylphosphorodithioate predominated at high and diethylphosphate at low concentrations of total metabolites. The correlation between the maximum concentrations of total metabolites, measured in urine of poisoned persons on the day of admission to hospital or a day later, and the initial depression of serum cholinesterase (EC 3.1.1.8) and erythrocyte acetylcholinesterase (EC 3.1.1.7) activities was poor (r = 0.6).

Urinary excretion of diethylphosphorus metabolites in persons poisoned by quinalphos or chlorpyrifos.

The urinary excretion rates of diethyl phosphate and diethyl phosphorothioate and changes in blood cholinesterase activities were studied in fifteen persons self-poisoned either by the organophosphorus pesticide quinalphos (twelve persons) or by chlorpyrifos (three persons). The organophosphate poisoning was always indicated by a significant depression of serum and/or red blood cell cholinesterase activities. The return of serum cholinesterase activity in the range of referent values took more than 30 days and had a different course in different persons. The most rapid increase in red blood cell acetylcholinesterase activity was noted within 24 h after the first treatment with oximes Pralidoxime and/or HI-6. None of the spot urine samples, collected daily after admission of persons to hospital, contained measurable quantities of the parent pesticide. There was no correlation between the maximum concentration of total urinary diethylphosphorus metabolites normalized to creatinine and the initial inhibition of blood cholinesterase activities measured in samples collected on the day of admission to hospital. The excretion of metabolites followed the kinetics of a biphasic reaction. The half-time of urinary metabolites concentration decrease in the fast excretion phase in quinalphos poisoned persons was 5.5-14.2 h (eight persons) and 26.8-53.6 h (four persons) and in chlorpyrifos poisoned persons 3.5-5.5 h. The half-time for the slow excretion phase ranged from 66.5 to 127.9 h in all persons and for both compounds. For a given person, the rates of excretion of diethyl phosphate and diethyl phosphorothioate were about the same. However, in quinalphos poisoned persons the proportions of single metabolites in total diethylphosphorus metabolites varied with the initial maximum concentration of total metabolites.(ABSTRACT TRUNCATED AT 250 WORDS)