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Ozcan Erel

Publications and source records attributed to Ozcan Erel.

At least 37 records · Page 2Linked to original sources
PubMed2005

Measurement of the total antioxidant response using a novel automated method in subjects with nonalcoholic steatohepatitis.

BACKGROUND: Oxidative stress, an increase in oxidants and/or a decrease in antioxidant capacity, is one of the potential biochemical mechanisms involved in the pathogenesis of nonalcoholic steatohepatitis. We aimed to investigate the total antioxidant response using a novel automated method in nonalcoholic steatohepatitis subjects. As a reciprocal measure, we also aimed to determine total peroxide level in the same plasma samples. METHODS: Twenty-two subjects with biopsy proven nonalcoholic steatohepatitis and 22 healthy controls were enrolled. Total antioxidant response and total peroxide level measurements were done in all participants. The ratio percentage of total peroxide level to total antioxidant response was regarded as oxidative stress index. RESULTS: Total antioxidant response of subjects with nonalcoholic steatohepatitis was significantly lower than controls (p < 0.05), while mean total peroxide level and mean oxidative stress index were higher (all p < 0.05). In subjects with nonalcoholic steatohepatitis, fibrosis score was significantly correlated with total peroxide level, total antioxidant response and oxidative stress index (p < 0.05, r = 0.607; p < 0.05, r = -0.506; p < 0.05, r = 0.728, respectively). However, no correlation was observed between necroimflamatory grade and those oxidative status parameters (all p > 0.05). CONCLUSION: Nonalcoholic steatohepatitis is associated with increased oxidant capacity, especially in the presence of liver fibrosis. The novel automated assay is a reliable and easily applicable method for total plasma antioxidant response measurement in nonalcoholic steatohepatitis.

Adult↗
PubMed2005

Increased oxidative stress associated with the severity of the liver disease in various forms of hepatitis B virus infection.

BACKGROUND: Oxidative stress can be defined as an increase in oxidants and/or a decrease in antioxidant capacity. There is limited information about the oxidative status in subjects with hepatitis B virus infection. We aimed to evaluate the oxidative status in patients with various clinical forms of chronic hepatitis B infection. METHODS: Seventy-six patients with hepatitis B virus infection, in whom 33 with chronic hepatitis, 31 inactive carriers and 12 with cirrhosis, and 16 healthy subjects were enrolled. Total antioxidant response and total peroxide level measurement, and calculation of oxidative stress index were performed in all participants. RESULTS: Total antioxidant response was significantly lower in cirrhotics than inactive HbsAg carriers and controls (p = 0.008 and p = 0.008, respectively). Total peroxide level and oxidative stress index was significantly higher in cirrhotic (p < 0.001, both) and chronic hepatitis B subjects (p < 0.001, both) than inactive HbsAg carriers and controls. Total antioxidant response was comparable in chronic hepatitis B subjects, inactive HbsAg carriers and controls (both, p > 0.05/6). Total peroxide level and oxidative stress index were also comparable in inactive HBsAg carriers and controls (both, p > 0.05/6). Serum alanine amino transferase level was positively correlated with total peroxide level and oxidative stress index only in chronic hepatitis B subjects (p = 0.002, r = 0.519 and p = 0.008, r = 0.453, respectively). CONCLUSION: Oxidative stress occurs secondarily to increased total lipid peroxidation and inadequate total antioxidant response and is related to severity of the disease and replication status of virus in hepatitis B infection.

Adult↗
PubMed2005

A new automated colorimetric method for measuring total oxidant status.

OBJECTIVES: To develop a new, colorimetric and automated method for measuring total oxidation status (TOS). DESIGN AND METHODS: The assay is based on the oxidation of ferrous ion to ferric ion in the presence of various oxidant species in acidic medium and the measurement of the ferric ion by xylenol orange. The oxidation reaction of the assay was enhanced and precipitation of proteins was prevented. In addition, autoxidation of ferrous ion present in the reagent was prevented during storage. The method was applied to an automated analyzer, which was calibrated with hydrogen peroxide and the analytical performance characteristics of the assay were determined. RESULTS: There were important correlations with hydrogen peroxide, tert-butyl hydroperoxide and cumene hydroperoxide solutions (r=0.99, P<0.001 for all). In addition, the new assay presented a typical sigmoidal reaction pattern in copper-induced lipoprotein autoxidation. The novel assay is linear up to 200 micromol H2O2 Equiv./L and its precision value is lower than 3%. The lower detection limit is 1.13 micromol H2O2 Equiv./L. The reagents are stable for at least 6 months on the automated analyzer. Serum TOS level was significantly higher in patients with osteoarthritis (21.23+/-3.11 micromol H2O2 Equiv./L) than in healthy subjects (14.19+/-3.16 micromol H2O2 Equiv./L, P<0.001) and the results showed a significant negative correlation with total antioxidant capacity (TAC) (r=-0.66 P<0.01). CONCLUSIONS: This easy, stable, reliable, sensitive, inexpensive and fully automated method that is described can be used to measure total oxidant status.

Autoanalysis↗
PubMed2005

Increased DNA damage and oxidative stress in patients with cutaneous leishmaniasis.

Cutaneous leishmaniasis (CL) is a chronic infectious and granulomatous disease caused by the Leishmania parasite that invades the skin. Reactive oxygen and nitrogen species (ROS and RNS) produced during an inflammatory response are an important part of host-defense strategies of organisms to kill the parasite. However, it is not well known whether these intermediates cause DNA damage in CL patients. We investigated the effect of Leishmania infection on basal levels of DNA strand breaks and on the oxidative/anti-oxidative status of patients with CL, and compared the data with those of healthy subjects. Twenty-five CL patients and 19 age- and sex-matched control subjects were enrolled in the study. We used the single-cell gel electrophoresis (also called comet assay) to measure DNA strand breaks in peripheral blood mononuclear leukocytes. Plasma protein carbonyl (PC), malondialdehyde (MDA) and total peroxide (TP) concentrations were measured to determine oxidative status and total anti-oxidative response (TAR) in plasma was measured to determine anti-oxidative status. The mean values of DNA damage and MDA and TP concentrations were significantly higher in CL patients than in the control group (p<0.001, p<0.01 and p<0.001, respectively). PC levels were also higher in patients, but this was not statistically significant (p>0.05). There was a significantly positive correlation between plasma MDA and DNA damage (r=0.524, p<0.01), and a negative correlation between TAR and TP levels (r=-0.790, p<0.001) in the patient group. These findings support the notion that ROS and RNS produced by the organism as a defense strategy may amplify the leishmanicidal activity in patients with CL. However, these intermediates not only cause the killing of the parasite but also induce oxidative damage in non-infected cells. Therefore, these patients must be treated urgently to counteract the oxidative DNA damage.

Adolescent↗
PubMed2005

Increased oxidative stress in infants exposed to passive smoking.

The purpose of this study was to assess the effect of passive cigarette smoking on the oxidative and anti-oxidative status of plasma in infants. Eighty-four infants aged 6-28 weeks were divided into two groups: the study group included infants who had been exposed to passive smoking via at least five cigarettes per day for at least the past 6 weeks at home, while the control group included infants who had never been exposed to passive smoking. The antioxidative status of plasma was assessed by the measurement of individual antioxidant components: vitamin C, albumin, bilirubin, uric acid, thiol contents and total antioxidant capacity (TAC 1 and TAC 2). Oxidative status was assessed by the determination of total peroxide levels and the oxidative stress index (OSI 1 and OSI 2). Plasma vitamin C, thiol concentration and TAC 1 and TAC 2 levels were significantly lower, whereas plasma total peroxide levels and OSI 1 and OSI 2 were significantly higher, in passive smoking infants than in the controls (P<0.01). We conclude that passive smoking has a negative impact on numerous parts of the antioxidant defence system in infants, and exposes them to potent oxidative stress.

Antioxidants↗
PubMed2005

Increased oxidative stress in children exposed to passive smoking.

BACKGROUND: Atherogenic process is accelerated with cigarette smoke that contains many oxidants and prooxidants, capable of producing free radical and enhancing the oxidative stress. We investigated oxidative and antioxidative status of children who had been exposed to passive smoking and compared with those of not exposed group. METHODS: One hundred forty-three school children aged 9-13 years, 61 of whom had never been exposed to passive smoking, and 82 of whom had been exposed to passive smoking at least 10 cigarette per day for at least last 1 year in their house, were enrolled in this study. Total antioxidative response (TAR) was measured to determine antioxidative status of plasma, and total peroxide concentration was measured to determine oxidative status of plasma. The ratio of TAR to total peroxide was accepted as an indicator of oxidative stress. RESULTS: TAR of plasma was significantly lower in children exposed to passive smoking than in those of not exposed group (p=0.018). Mean (S.D.) values were 1.49 (0.07) and 1.52 (0.08) mmol Trolox Equiv./l, respectively. In contrary, the mean (S.D.) total peroxide level of plasma was significantly higher in children exposed to passive smoking [13.06 (2.34) micromol H2O2/l] than in not exposed group [12.24 (1.74) micromol H2O2/l] (p=0.015). The mean (S.D.) oxidative stress index (OSI) value was significantly higher in the children exposed to passive smoking [0.87 (0.15)] than in not exposed group [0.80 (0.10)] (p=0.001). CONCLUSION: Children who are exposed to passive smoking are exposed to oxidative stress, which has been implicated in the etiopathogenesis of over 100 disorders including atherosclerosis.

Adolescent↗
PubMed2005

Increased DNA damage in patients with complete hydatidiform mole.

The pathologic mechanisms underlying the gestational trophoblastic diseases are largely unexplored, but are thought to involve oxidative damage to the maternal vasculature and also to the placenta. In this study we have assessed the plasma levels of total antioxidant response (TAR) and the levels of endogenous DNA damage--determined by the comet assay--in peripheral blood lymphocytes from 13 women with complete hydatidiform mole (CHM) and compared these with those of 12 healthy pregnant controls and 10 healthy non-pregnant controls. Significantly lower mean levels of plasma TAR were found in patients with CHM compared with healthy pregnant controls (1.08+/-0.29 versus 1.17+/-0.14 mmol Trolox Eq/L, p<0.05) and with healthy non-pregnant controls (1.08+/-0.29 versus 1.38+/-0.12 mmol Trolox Eq/L, p<0.05). Significantly higher mean levels of endogenous DNA damage were observed in patients with CHM than in healthy pregnant controls (234.5+/-50.74 versus 125.7+/-45.4 AU, p<0.05) or in healthy non-pregnant controls (234.5+/-50.74 versus 104.0+/-49.6 AU, p<0.05). We observed an inverse correlation between the plasma TAR and the levels of endogenous DNA damage (r=-0.64, p<0.01), in that the levels of oxidative damage to the DNA were found to parallel the decrease in the plasma TAR in the CHM group. These results reveal a relationship between the extracellular and intracellular (as reflected by damage to the DNA) levels of oxidation. Our observations suggest that there is a link between the increased levels of oxidative stress and the increase in endogenous DNA damage seen in patients with CHM, as compared with those seen in normal pregnancy. However, the nature of this link, and whether it is direct or indirect, remains to be explored.

Adult↗
PubMed2005

Measurement of the total antioxidant response in preeclampsia with a novel automated method.

OBJECTIVES: Preeclampsia is one of the most serious complications of pregnancy. Free radical damage has been implicated in the pathophysiology of this condition. In this study, we aimed to measure the antioxidant capacity in plasma samples from normotensive and preeclamptic pregnant women to evaluate their antioxidant status using a more recently developed automated measurement method. STUDY DESIGN: Our study group contained 42 women, 24 of whom had preeclampsia, while 18 had normotensive pregnancies. We measured the total plasma antioxidant capacity for all patients, as well as the levels of four major individual plasma antioxidant components; albumin, uric acid, ascorbic acid and bilirubin, and as a reciprocal measure, their total plasma peroxide levels. RESULTS: Statistically significant differences (determined using Student's t-test) were noted between the normotensive and the preeclamptic groups for their total antioxidant responses and their vitamin C levels (1.31 +/- 0.12 mmol versus 1.06 +/- 0.41 mmol Trolox eq./L; 30.2 +/- 17.83 micromol/L versus 18.1 +/- 11.37 micromol/L, respectively), which were both considerably reduced in the preeclamptic patients. In contrast, the total plasma peroxide levels were significantly elevated in this group (49.8 +/- 14.3 micromol/L versus 38.8 +/- 9.6 micromol/L). CONCLUSIONS: We found a decreased total antioxidant response in preeclamptic patients using a simple, rapid and reliable automated colorimetric assay, which may suitable for use in any routine clinical biochemistry laboratory, and considerably facilitates the assessment of this useful clinical parameter. We suggest that this novel method may be used as a routine test to evaluate and follow up of the levels of oxidative stress in preeclampsia.

Adult↗
PubMed2005

The association of total antioxidant capacity with sex hormones.

OBJECTIVE: Although sex hormones have potential cardioprotective effects, their effects on total antioxidant capacity (TAC) are not very well known. The aim of the study was to evaluate TAC in men who have decreased and normal testosterone levels and in women in menopausal and premenopausal period. DESIGN: Ninety-seven subjects with similar age intervals, men aged <45 years and female aged <50 years, were divided into four groups: 1) 10 men with normal testosterone levels, as control, 2) 36 men with decreased testosterone, 3) 19 women in menopause, surgically induced, and 4) 32 women in premenopausal period. Testosterone and estrogen levels were measured by chemiluminescence assay and TAC were measured by using a more recently developed automated measurement method. RESULTS: The TAC was significantly lower in Group 2 and Group 3 than those of Group 1 and Group 4 (ANOVA, p<0.001). A strong correlation between TAC, and testosterone and estrogen were found (r=0.807, p<0.001; r=0.685, p<0.001, testosterone and estrogen respectively). CONCLUSIONS: The observed relationship between sex hormones and TAC may have a role in mechanism of their cardioprotective effect.

Adult↗
PubMed2005

Decreased total antioxidant capacity and increased oxidative stress in passive smoker infants and their mothers.

BACKGROUND: Smoking has many adverse health effects in infants and adults. The purpose of the study was to study the effect of passive cigarette smoking on oxidative and antioxidative status of plasma in passive smoker infants and their mothers and to compare with those of non-smokers. METHODS: Subjects were randomly chosen from infants aged 8-26 weeks and their mothers aged 20-34 years. Passive smoker infants (n = 29) and their mothers (n = 29) were defined as having other family members who smoked six or more cigarettes per day continually for at least 8 weeks. Non-smokers were defined as infants (n = 30) and their mothers (n = 24) who had never been exposed to passive smoking. The antioxidative status of plasma were perused by measuring the total antioxidant capacity. Oxidative status was evaluated by predicating total peroxide level, oxidative stress index, protein oxidation and lipid peroxidation. RESULTS: Plasma concentrations of total antioxidant capacity were significantly lower in passive smoker infants and their mothers than non-passive smoker infants and their mothers. However, lipid peroxidation and oxidative stress index were remarkably higher in passive smoker infants and their mothers than those of non-passive smoker infants and their mothers. There were significant correlations between the oxidative and antioxidative parameters of the passive smoker infants and their mothers. CONCLUSIONS: Oxidants are increased and antioxidants are decreased in passive smoker infants and their mothers than those of non-smokers. Passive smoker infants and their mothers are exposed to potent oxidative stress.

Adult↗
PubMed2005

Essential trace elements selenium, zinc, copper, and iron concentrations and their related acute-phase proteins in patients with vivax malaria.

The aim of the present study is to evaluate the status of plasma essential trace elements selenium (Se), zinc (Zn), copper (Cu), and iron (Fe) concentrations and their related acute-phase proteins, ceruloplasmin (Cp), ferritin, transferrin (Tf), and albumin levels in patients with vivax malaria. Plasma Cu and Zn concentrations were determined by atomic absorption spectrometry (AAS). Se concentrations were determined by graphite furnace AAS. Fe, Cp, Tf, and albumin levels were determined by colorimetric methods. Plasma Se, Fe, and albumin levels were found to be significantly lower (p < 0.01, p < 0.001, and p < 0.05, respectively) and Cu, Cp, and ferritin levels and Cu/Zn ratios were significantly higher (p < 0.001, p < 0.001, p < 0.001, and p < 0.05, respectively) in patients when compared with those of healthy subjects. Plasma, Tf, and Zn levels were not found to be significantly different (p > 0.05) in patients and controls. There were positive important correlations between Cu and Cp (r = 0.908, p < 0.001), Zn and albumin (r = 0.633, p < 0.001), and negative correlations between Fe and ferritin content (r = -0.521, p < 0.05) and Fe and Tf (r = -0.616, p < 0.01) in the patients group. Our findings demonstrated that plasma essential trace elements Se, Cu, and Fe change, but these changes might be dependent on acute-phase proteins, which were regulated as a part of defense strategies of the organism, induced by hormonelike substances.

Acute-Phase Proteins↗
PubMed2005

The relationship between potency of oxidative stress and severity of dilated cardiomyopathy.

BACKGROUND: It has been suggested that oxidative stress may have a role in the etiopathogenesis of congestive heart failure. OBJECTIVES: To investigate and compare the oxidative-antioxidative status and oxidative stress index (OSI) of patients with idiopathic dilated cardiomyopathy (IDC) with those of healthy volunteers, and to determine the relationship between total antioxidant capacity (TAC) and ejection fraction (EF). METHODS: Twenty-eight patients with IDC and 24 control subjects were enrolled in the study. Antioxidative status was evaluated by measuring the TAC and the vitamin C and thiol levels in the plasma. Oxidative status was evaluated by measuring the total peroxide level. The per cent ratio of TAC to total peroxide level was accepted as the OSI. EF was measured using Simpson's method. RESULTS: TAC and vitamin C and thiol levels of plasma were found to be significantly lower in patients with IDC than in control subjects (P < 0.001). In contrast, total peroxide levels and OSIs were significantly higher in patients with IDC than in control subjects (P = 0.002 and P = 0.002, respectively). An important positive correlation was found between TAC and EF (r = 0.772; P < 0.001). On the other hand, significant negative correlations were found between EF and OSI and between EF and total peroxide levels in patients. CONCLUSIONS: Oxidants are increased and antioxidants are decreased in patients with IDC; as a result, the oxidative-antioxidative balance is shifted to the oxidative side. There is a significant correlation between the potency of oxidative stress and the severity of IDC. It is believed that supplementation of antioxidants in the treatment of IDC may be helpful to these patients.

Age Distribution↗
PubMed2004

A novel automated method to measure total antioxidant response against potent free radical reactions.

OBJECTIVES: Oxidative damage of biomolecules occurs as a result of potent free radical reactions. In this study, a novel, colorimetric and fully automated method for measuring total antioxidant response (TAR) against potent free radical reactions is described. DESIGN AND METHODS: Potent free radical reactions were initiated with the production of hydroxyl radical (OH(*)) via Fenton reaction, and the rate of the reactions was monitored by following the absorbance of colored dianisidyl radicals. Ortho-dianisidine (10 mM) and ferrous ammonium sulfate (45 microM) were dissolved in KCl/HCl solution (75 mM, pH 1.8). This mixture was named as Reagent 1 and hydrogen peroxide solution (7.5 mM) as Reagent 2. The OH(*), produced by mixing of R1 and R2, oxidized o-dianisidine molecules into dianisidyl radicals, leading to a bright yellow-brown color development within seconds. Antioxidants, present in the sample, suppressed the color formation to a degree that is proportional to their concentrations. The method was applied to an automated analyzer and analytical performance characteristics of the assay were determined. RESULTS: Vitamin C and Trolox, reduced glutathione, bilirubin, uric acid and (+/-)-catechin solutions suppressed the color formation depending on their concentrations. Serum TAR against potent free radical reactions was lower in patients with chronic renal failure (1.13 +/- 0.21 mmol Trolox equiv./l) and was higher in the individuals with neonatal icterus (2.82 +/- 1.18 mmol Trolox equiv./l) than in healthy subjects (1.54 +/- 0.15 mmol Trolox equiv./l). CONCLUSIONS: The easy, inexpensive and fully automated method described can be used to measure TAR of samples against potent free radical reactions.

Antioxidants↗
PubMed2004

A novel automated direct measurement method for total antioxidant capacity using a new generation, more stable ABTS radical cation.

OBJECTIVES: To develop a novel colorimetric and automated direct measurement method for total antioxidant capacity (TAC). DESIGN AND METHODS: A new generation, more stable, colored 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid radical cation (ABTS(*+)) was employed. The ABTS(*+) is decolorized by antioxidants according to their concentrations and antioxidant capacities. This change in color is measured as a change in absorbance at 660 nm. This process is applied to an automated analyzer and the assay is calibrated with Trolox. RESULTS: The novel assay is linear up to 6 mmol Trolox equivalent/l, its precision values are lower than 3%, and there is no interference from hemoglobin, bilirubin, EDTA, or citrate. The method developed is significantly correlated with the Randox- total antioxidant status (TAS) assay (r = 0.897, P < 0.0001; n = 91) and with the ferric reducing ability of plasma (FRAP) assay (r = 0.863, P < 0.0001; n = 110). Serum TAC level was lower in patients with major depression (1.69 +/- 0.11 mmol Trolox equivalent/l) than in healthy subjects (1.75 +/- 0.08 mmol Trolox equivalent/l, P = 0.041). CONCLUSIONS: This easy, stable, reliable, sensitive, inexpensive, and fully automated method described can be used to measure total antioxidant capacity.

Antioxidants↗
PubMed2003

Increased oxidative stress in patients with hydatidiform mole.

OBJECTIVE: The aim of this study was to determine the oxidative status and antioxidative status of plasma of patients with complete hydatidiform mole (CHM) and to compare these values with normal pregnancy. METHOD: Thirty-eight patients with CHM and 31 healthy pregnant women were enrolled in the study. To determine the antioxidative status of plasma, total antioxidant potential (TAOP) was calculated, and to determine the oxidative status of plasma total peroxide levels were measured. The ratio of TAOP to total peroxide was accepted as an indicator of oxidative stress. RESULTS: TAOP of plasma was significantly lower in patients with hydatidiform mole than in healthy pregnant women [mean (SD) values were 511.9 (105.8) and 571.7 (109.4) micromol Trolox equiv./L respectively (p <0.05)]. In contrast, mean (SD) total peroxide level of plasma was significantly higher in the patients [21.8 (6.4) micromol H2O2/L] than in healthy pregnant women [15.6 (6.4) micromol H2O2/L (p <0.001)]. The mean oxidative stress index level was significantly higher in patients with CHM than in healthy pregnant women [4.43 (1.70) versus 2.92 (1.50) respectively (p <0.001)]. CONCLUSION: Patients with CHM are exposed to oxidative stress, which may have a role in the pathogenesis of the disease. Supplementation with antioxidative vitamins such as C and E could be considered in treatment.

Adult↗
PubMed2002

Antioxidative effects of exogenous nitric oxide versus antioxidant vitamins on renal ischemia reperfusion injury.

The objectives of this study were to compare the protective influence of exogenous nitric oxide on renal ischemia reperfusion (I/R) injury with that of the antioxidant vitamins C and E. Sprague-Dawley rats were divided into three groups ( n=12 per group). Normal saline solution was given in group 1, a vitamin C (200 mg/kg/d) plus vitamin E (100 mg/kg/d) combination in group 2 for 3 days before operating and Na-nitroprusside (5 mg/kg/d) in group 3 before reperfusion. The left kidneys were exposed to warm ischemia for 40 min followed by reperfusion for 90 min. The right kidneys were used as internal controls. After both kidneys were removed, histopathological examinations were performed, and oxidative and antioxidative parameters were measured. In the postischemic reperfused rat kidneys, the renal lipid peroxidation level was significantly lower, and the renal GSH level higher in the group given Na-nitroprusside compared with groups 1 and 2. Renal specific xanthine oxidase activity was also significantly lower in the group treated with Na-nitroprusside than in the groups given vitamins or saline. There was a significant, negative correlation between lipid peroxidation and reduced glutathione levels. Our results suggest that the exogenous nitric oxide (Na-nitroprusside) inhibits xanthine oxidase, and has more apparent preventive features for renal I/R injury than the antioxidant vitamins C+E.

Animals↗
PubMed2002

Semi-automated enzymatic measurement of serum zinc concentration.

OBJECTIVE: To measure serum zinc concentration by means of carbonic anhydrase reactivation using an automated analyzer. METHODS: The zinc content of carbonic anhydrase (CA), whose cofactor is zinc, was removed by dialysis against pyridine 2 to 6 dicarboxylic acid and a pure apoenzyme was obtained. Serum proteins were precipitated with trichloroacetic acid (TCA) solution and the supernatant fraction of the sample was used to determine the zinc concentration. The negative effects of the precipitant on CA activity in the assay were completely removed, reaction conditions for maximal CA activity were provided and the color of the product was enhanced and stabilized. P-nitrophenyl acetate was used as the substrate and the change of absorbance of p-nitrophenol which was produced was followed at 400 nm. The initial rate of the esterase activity of CA was measured by using an automated analyzer. Analytical performance characteristics of the assay were determined. The zinc concentrations in serum samples of healthy subjects and patients were measured. RESULTS: The enzymatic assay is accurate, sensitive, specific and is not affected by other metals. There was excellent agreement with the results obtained using an atomic absorption spectrophotometer (AAS) (y = 0.98X + 0.18, r = 0.99). Serum zinc concentrations were found to be higher in patients with vivax malaria, and lower in patients with cutaneous leishmaniasis than in healthy subjects. CONCLUSION: The enzymatic method is suitable for semiautomated measurement of serum zinc concentration.

Autoanalysis↗