A reliable chromatographic method for the simultaneous determination of ciprofloxacin and moxifloxacin in human serum

Purpose: To develop and validate a simple chromatographic method for the analysis of ciprofloxacin and moxifloxacin in human serum.Methods: After protein precipitation had been performed, high performance liquid chromatography (HPLC) with UV detection was utilized for the analysis of ciprofloxacin and moxifloxacin in human serum. Analytical column Zorbax SB-C18 (150 mm x 4.6 mm i.d., particle size 3.5 μm) was used as a stationary phase. Chromatographic separation was realized with the mobile phase 0.1% trifluoroacetic acid in water for chromatography - methanol (66:34, v/v), at the flow rate of 1 mL/min, temperature of 35 oC and detection at 280 nm. The method validation was performed according to the guidelines of the European Medicines Agency (EMA).Results: The chromatographic run time was about 12 minutes and no interference was observed. For ciprofloxacin, the method was linear over a concentration range of 0.5-50 μg/mL, with a correlation coefficient of 0.9874. For moxifloxacin, the method was linear over a concentration range of 0.5-50 μg/mL, with a correlation coefficient of 0.9946. Since relative standard deviation (RSD) and relative recovery values were within acceptable limits according to EMA guidelines, good intra-day precision, inter-day precision, as well as the accuracy of the method, were observed.Conclusion: A simple and reliable HPLC-UV method has been developed and validated for the simultaneous determination of ciprofloxacin and moxifloxacin in human serum. The method can be applied for therapeutic drug monitoring but also and pharmacokinetic studies of ciprofloxacin and moxifloxacin. Keywords: Human serum, Ciprofloxacin, Moxifloxacin, Protein precipitation, HPLC, UV detection, Method validation

Can phytoplankton blooming be harmful to benthic organisms? The toxic influence of Anabaena sp. and Chlorella sp. on Chironomus riparius larvae

Cyanobacteria and microalgae are abundant biota groups in eutrophic freshwater ecosystems, serving as a food source for many aquatic organisms, including the larvae of non-biting midges (Chironomidae). Many species of cyanobacteria are toxin producers, which can act as stressors to other organisms. The present study aimed to analyze and compare the effects of dietary exposure to the common toxic cyanobacteria Anabaena sp. and non-toxic microalgae Chlorella sp. in Chironomus riparius larvae. Microcystin was detected and quantified in the methanolic extract of Anabaena sp. using the HPLC-DAD technique, and it was identified as microcystin-LR. Both Anabaena sp. and Chlorella sp. were suitable food sources to enable the survival of C. riparius larvae in laboratory conditions, causing negligible mortality and significant differences in the larval mass (ANOVA and Post hoc LSD test; p < 0.05) and hemoglobin concentration (Student's t-test; p < 0.05). Oxidative stress parameters such as advanced oxidation protein products (AOPP), thiobarbituric acid reactive substances (TBARS), catalase (CAT) and superoxide dismutase (SOD) activity, and DNA damage, were also investigated. One-way ANOVA, followed by the Post hoc LSD test, showed a significant increase in AOPP and CAT for the group of larvae fed with Chlorella sp. The same test showed moderate DNA damage in both groups of larvae, with greater damage in the group fed with Anabaena sp. Thus, Chlorella sp. and microcystin-LR producing Anabaena sp. are food sources that did not result in any drastic acute effect on the population level of C. riparius larvae. However, sub-individual-level endpoints revealed significant effects of the treatments, since they caused oxidative stress and DNA damage that may pose a danger to successive generations of test organisms.

Correlation between oxidative stress parameters and left ventricular geometry in patients with chronic heart failure

Oxidative stress, as one of the pathophysiological mechanisms involved in the reduction of myocardial contractility, stimulates the proliferation of cardiac fibroblasts and the activation of matrix metalloproteinases, which leads to extracellular matrix remodeling. Left ventricular hypertrophy (LVH) is a well-known independent risk factor for cardiovascular events. The aim of this research was to determine the connection between the parameters of oxidative stress and left ventricular geometry indicators in patients with chronic heart failure. The study included 81 subjects diagnosed with heart failure and 68 subjects in the control group. Parameters of myocardial morphology and left ventricular function were measured by echocardiography. Thiobarbituric acid reactive substances (TBARS) content, advanced oxidation protein products (AOPP), total serum SH groups and catalase activity were performed in both groups. The results showed that there were significantly higher concentrations of TBARS, AOPP, and SH groups in patients compared to controls (p < 0.01) and higher concentration of TBARS in patients with concentric hypertrophy compared to patients with normal geometry (p < 0.05). Correlation analysis showed a strong positive correlation between geometry parameters and myocardial function and TBARS and negative correlation between the right ventricule diameter and catalase activity. The results of this study show that oxidative stress parameters are significantly elevated in patients with heart failure, and that concentrations of TBARS and AOPP - the markers of lipid and protein oxidation, strongly correlate with left ventricular geometry parameters.

Adverse effects of mycophenolic acid in renal transplant recipients: gender differences

Background Mycophenolic acid is widely used immunosuppressive drug, associated with adverse effects which increase patient morbidity and decrease medication adherence. Objective To evaluate the adverse effects in renal transplant recipients under mycophenolate treatment with respect to gender. Setting University Clinical Centre of Nis, Clinic of Nephrology, Serbia. Method This research included 96 renal transplant recipients, who received immunosuppressive regimen, based on tacrolimus or cyclosporin A, prednisone and mycophenolic acid. The high-performance liquid chromatography method combined with protein precipitation was used for the analysis of mycophelate concentration in human plasma. Drug concentration and dose-adjusted concentration were determined with respect to the patients' gender. An adverse effect scoring system developed by nephrologists within the University of Buffalo Nephrology/Transplant Program was used to monitor adverse effects of therapy. Main outcome measure Individual and scores of adverse effects in relation to the dosing regimen and gender. Results Results showed statistically lower dose and concentrations in men compared to the women in our investigation group. Also, female patients demonstrated higher mean scores (cumulative and subscores) within the same dosing regimens of mycophenolic acid. The gastrointestinal score was significantly higher in women who received a dose greater than 720 mg compared to men (0.20 ± 0.12 vs 0.12 ± 0.12). Women demonstrated higher individual adverse effects such as diarrhea and skin changes (41.7 vs 17.0; p = 0.038 and 62.5 vs 30.2; p = 0.037, respectively). Conclusions The results of our research showed that recipients' gender may play an important role in pharmacokinetic profile of mycophenolic acid, suggesting that women had higher concentration of mycophenolic acid and more serious side effects.

Metronidazole- and levofloxacin-induced psychotic disorders in chronic kidney patient

We present a case which reports the occurrence of psychotic disorders after metronidazole and levofloxacin therapy in a chronic kidney patient while being treated for enterocolitis and urinary infection. A 48-year-old female was admitted to a hospital for the placement of a peritoneal dialysis catheter due to indicated peritoneal dialysis. During admission, symptoms of enterocolitis and urinary infection had occurred, so metronidazole and levofloxacin were introduced into therapy, respectively. After 4 days of metronidazole and 3 days of levofloxacin therapy, the patient became confused, disoriented, with signs of delirium. Since the diagnosis of psychoorganic disorder was made, the therapy with lorazepam and haloperidol was initiated, while metronidazole and levofloxacin were discontinued. Complete recovery 4 days after discontinuation indicates that the patient has experienced antibiotics-induced neurotoxicity. This is the first report of expressed neurotoxicity after the combination of metronidazole and levofloxacin in chronic kidney patients.

Current Biochemical Monitoring and Risk Management of Immunosuppressive Therapy after Transplantation

Immunosuppressive drugs play a crucial role in the inhibition of immune reaction and prevention of graft rejection aswell as in the pharmacotherapy of autoimmune disorders. Effective immunosuppression should provide an adequate safety profile and improve treatment outcomes and the patients' quality of life. High-risk transplant recipients may be identified, but a definitive prediction model has still not been recognized. Therapeutic drug monitoring (TDM) for immunosuppressive drugs is an essential, but at the same time insufficient tool due to low predictability of drug exposition and marked pharmacokinetic variability. Parallel therapeutic, biochemical and clinical monitoring may successfully optimize and individualize therapy for transplanted recipients, providing optimal medical outcomes. Modern pharmacotherapy management should include new biomarkers with better sensitivity and specificity that can identify early cell damage. The aim of this study was to point out the importance of finding new biomarkers that would enable early detection of adverse drug events and cell damage in organ transplant recipients. We wanted to confirm the importance of routine biochemical monitoring in improving the safety of immunosuppressive treatment.

Concentration of Transforming Growth Factor-beta 1 in Chronic Periapical Lesions / Ispitivanje koncentracije transformišućeg faktora rasta beta 1 u hroničnim periapeksnim lezijama

Host response to antigen stimulation in chronic inflammatory periapical lesions is mainly controlled by the balance between proinflammatory and anti-inflammatory cytokines. The aim of this study was to determine the concentration of TGF-β1 in the tissue homogenates of periapical lesions and to analyse its level in relation to the symptomatology of the patients and size of the lesions. Ninety three samples of chronic periapical lesions were obtained after extraction of teeth. Samples were divided according to the clinical symptoms as symptomatic and asymptomatic, and according to the size as large and small. The concentration of TGF-β1 was analyzed using ELISA. The results showed increased production of TGF-β1 in symptomatic lesions compared to asymptomatic, but the difference was not statistically significant. Statistically significant difference in TGF-β1 concentrations was observed in large lesions compared to small (p<0,001). It seems that TGF-β1 have a modulating effect on bone tissue resorption activity under the influence of proinflammatory cytokines and can be molecular prognostic marker of periapical lesion healing.

C-reactive protein and chitinase 3-like protein 1 as biomarkers of spatial redistribution of retinal blood vessels on digital retinal photography in patients with diabetic retinopathy

The aim of the study was to investigate the correlation between the levels of C-reactive protein (CRP) and chitinase 3-like protein 1 (YKL-40) in blood samples with morpohometric parameters of retinal blood vessels in patients with diabetic retinopathy. Blood laboratory examination of 90 patients included the measurement of glycemia, HbA1C, total cholesterol, LDL-C, HDL-C, triglycerides and CRP. Levels of YKL-40 were detected and measured in serum by ELISA (Micro VueYKL-40 EIA Kit, Quidel Corporation, San Diego, USA). YKL-40 correlated positively with diameter and negatively with number of retinal blood vessels. The average number of the blood vessels per retinal zone was significantly higher in the group of patients with mild non-proliferative diabetic retinopathy than in the group with severe form in the optic disc and all five retinal zones. The average outer diameter of the evaluated retinal zones and optic disc vessels was significantly higher in the group with severe compared to the group with mild diabetic retinopathy. Morphological analysis of the retinal vessels on digital fundus photography and correlation with YKL-40 may be valuable for the follow-up of diabetic retinopathy.

Anti-dsDNA, anti-nucleosome and anti-C1q antibodies as disease activity markers in patients with systemic lupus erythematosus

INTRODUCTION

In spite of the growing number of reports on the study of anti-nucleosome and anti-C1q antibodies, there are still controversies on their significance as disease activity markers in patients with systemic lupus erythematosus (SLE) and their use in everyday clinical practice.

OBJECTIVE

Our aim was to assess the presence of anti-dsDNA, anti-nucleosome and anti-C1q antibodies in SLE patients, as well as to establish their sensitivity, specificity, positive and negative predictive value, and their correlation with SLE and lupus nephritis clinical activity.

METHODS

The study enrolled 85 patients aged 45.3 +/- 9.7 years on the average, with SLE of average duration 10.37 +/- 7.99 years, hospitalized at the Institute,,Niska Banja" during 2011, and 30 healthy individuals as controls. Disease activity was assessed using Systemic Lupus Erythematosus Disease Activity Index (SLEDAI). In all examinees the levels of anti-dsDNA, anti-nucleosome and anti-C1q antibodies were measured using the ELISA method with Alegria Test Strips Orgentec (Germany).

RESULTS

Patients with active lupus nephritis had a higher presence of anti-C1q antibodies and higher co-positivity of anti-dsDNA, anti-nucleosome, and anti-C1q antibodies compared to those with inactive lupus nephritis (77.77% vs. 21.74%; p < 0.01). SLE patients with SLEDAI > or = 11 had a higher presence of antinucleosome (93.75% vs. 64.15%; p < 0.01) and anti-C1q antibodies (46.87% vs. 22.64%; p<0.05), as well as a higher mean level of anti-nucleosome antibodies (107.79 +/- 83.46 U/ml vs. 57.81 +/- 63.15 U/ml; p < 0.05), compared to those with SLEDAI of 0-10. There was a positive correlation between the SLEDAI and the level of anti-dsDNA (r=0.290; p<0.01), anti-nucleosome (r = 0.443; p < 0.001), and anti-C1q antibodies (r = 0.382; p < 0.001). Only anti-C1q antibodies demonstrated correlation with proteinuria (r = 0.445; p < 0.001).

CONCLUSION

Anti-nucleosome and anti-C1q antibodies demonstrated association with SLE and lupus nephritis activity, suggesting their potential usefulness in making predictions about lupus nephritis and assessment of disease activity.

Immunosuppressive medication adherence in kidney transplant patients

OBJECTIVES

To assess the degree of immunosuppressive medication adherence in kidney transplant patients (KTPs) and to determine if there is a difference in the rate of adherence to tacrolimus (Tac), cyclosporine (CsA) and sirolimus (Sir).

SUBJECTS AND METHODS

From a total of 63 KTPs treated at the Clinic of Nephrology, Clinical Centre Niš, Serbia, 60 participated in the study by responding to questionnaires. They were divided into the adherence group (n = 43) and the nonadherence group (n = 17) according to their degree of adherence which was measured using a validated survey form, the simplified medication adherence questionnaire. The KTP adherence to the different immunosuppressive regimens (Tac, CsA and Sir) was compared. Statistical analysis was performed using the Student t test.

RESULTS

Adherence was observed in 43 (71.7%) patients, and only 17 (28.3%) did not follow the prescribed therapy. The estimated glomerular filtration rate was significantly lower in the nonadherence group (38.52 ± 18.22 ml/min) than in the adherence group (52.43 ± 16.91 ml/min, p < 0.05). With regard to the Tac level, a significant difference was also found between the adherers and the nonadherers (6.30 ± 2.06 vs. 5.0 ± 1.52 ng/ml, p < 0.05).

CONCLUSION

The KTPs in this study demonstrated a high level of adherence. Nonadherence was associated with worse graft function and a lower Tac level. Knowledge about the degree of adherence could help the early identification of nonadherent patients and the development of strategies to improve this.

Determinants of atherosclerosis in children and adolescents with diabetes type 1

INTRODUCTION

To evaluate the degree of atherosclerosis in children and adolescents with type 1 diabetes and its correlation with risk factors, traditional and other, such as anti-oxidative capacity of circulating blood and level of lipid peroxidation.

MATERIAL AND METHODS

Forty children and adolescents with type 1 diabetes with mean age 13.7 years were compared with 20 age- and sex-matched healthy control subjects. Association of carotid artery intima-media thickness (cIMT) with different risk factors measured in children with type 1 diabetes was evaluated.

RESULTS

Mean carotid IMT was higher in subjects with diabetes (p 〈 0.01) and was strongly associated with total cholesterol with an odds ratio of 4.08 (p = 0.016), LDL-cholesterol with an odds ratio of 2.78 (p = 0.037), length of disease with an odds ratio of 1.87 (p = 0.007) and positive family history (first- and second-degree relatives) of diabetes and early CVD (heart attack and/or stroke before the age of 60 years) with an odds ratio of 6.8 (p = 0.007).

CONCLUSIONS

We found significantly increased cIMT in the diabetic patients compared to the healthy control subjects. Risk factors for the development of atherosclerosis included higher total and LDL-cholesterol, higher systolic blood pressure, positive family history of diabetes and early CVD and longer diabetes duration. In spite of the documented increased oxidative stress, we failed to establish a correlation between the oxidative stress parameters and cIMT values.

Gender differences in pharmacokinetics of tacrolimus and their clinical significance in kidney transplant recipients

BACKGROUND

The possible influence of gender on tacrolimus disposition and response in kidney transplant recipients is an issue of medical importance.

OBJECTIVE

The aim of this study was to detect interpatient pharmacokinetic variability of tacrolimus due to patients' gender and to assess the predictability of individual tacrolimus concentrations using abbreviated AUC measurements. The secondary objective was to find the best sampling time to predict the exposure of tacrolimus in kidney transplant recipients.

METHODS

Gender-related first oral dose tacrolimus pharmacokinetics studies were conducted in 20 Serbian kidney transplant recipients (10 men/10 women) on quaternary immunosuppressive therapy. The first tacrolimus oral dose (0.05 mg/kg) was given on day 5 post-transplant. Blood concentrations were measured by microparticle enzyme immunoassay method. Associations between each sampling time point of concentrations and 12 hours after the administration AUC (AUC(0-12)) were evaluated by Pearson correlation coefficients. Abbreviated sampling equations were derived by multiple stepwise regression analyses.

RESULTS

AUC(0-12) showed remarkable interindividual variations after the first tacrolimus oral dose. There were significantly lower values of AUC in women than men (P < 0.05). The most important time point influencing AUC(0-12) was the concentration of tacrolimus measured 2 hours after administration(C(2)) in women, whereas in men the most important time points were the concentrations at 1 (C(1)), 4 (C(4)), and 12 (C(12)) hours as an abbreviated AUC.

CONCLUSION

Our results show significant differences between men and women. C(2) seems to be indicator of total body exposure to tacrolimus in the early period after kidney transplant in women. The three-point sampling method seems to be a good indicator of abbreviated AUC for a tacrolimus monitoring strategy in men.

Arginase activity in human milk during the first month of lactation

Arginase (L-arginine amidinohydrolase, EC 3.5.3.1) is the key enzyme in urea synthesis, hydrolyzing L-arginine into L-ornithine and urea. Arginase modulates levels of nitric oxide, creatine, and creatinine, likely by regulating intracellular L-arginine availability. The objective of the present study was to determine the arginase activity and concentration of urea and creatinine in colostrum and mature human milk obtained from nursing mothers. Our longitudinal biochemical analyses show that arginase activities and urea concentrations were the highest at the first day of lactation (colostrum). The decreasing enzyme activity and urea start at the second day, remaining at this level until the end of the first month of lactation (30th day). The concentration of creatinine in human colostrum and mature milk did not significantly change. The alteration of arginase activity between colostrum and mature milk may be a consequence of the transfer of arginase from the blood of the breast mother mammary glands into the colostrum and mature milk. The concentration of nutrients in colostrum and mature milk undergo alterations, probably to satisfy the requirements of the nursing infant for arginine, essential amino acids for human body growth, and normal physiology.

Oxidative stress in cataractogenesis

The aim of our study was to compare levels of antioxidative agent -total SH groups and the final product of lipid peroxidation- malondialdehyde (MDA) in serum, and glutathione (GSH) and MDA in nucleocortical parts of lens after extracapsular extraction of cataract. Patient were (38 with cataract and 38 controls) matched by sex and years of life. Diagnosis of cataract was established by complete ocular examination. All results are expressed as mean ± S.D. A Student's t-test was used to estimate differences between the groups. The level of significance was p<0.05. Total sulfhydryl groups were determined in serum by the method of Ellman as well as GSH content in nucleocortical parts of lenses using the method of Sedlak and Lindsay. Lipid peroxidation, evidenced by formation of thiobarbituric acid reactive substances (TBARS), was determined in nucleocortical parts of the lens and in serum. Our results show a statistical significance in concentration of total SH groups (225.37±82.19µmol/L, controls 311.03±60.37µmol/L p<0.05) and MDA (20.24±8.12, and controls 8.73±2.53µmol/L, p<0,001) in serum among patients with age related cataract and controls. There was no statistical significance in concentration of total SH groups and MDA in serum among patients with different type of age related cataract and in nucleocortical parts of lens. The present study concludes that there is a statistical significance in concentration of total SH groups and MDA in serum among patients with age related cataract and controls, but there were no statistical significance in concentration of GSH and MDA in serum and nucleocortical parts of lens in patient with different type of cataract.

[Analysis of enzyme activity and the level of malondialdehyde in the saliva of children with gingivitis]

INTRODUCTION/AIM

By analysing activity of some of the enzymes normally present in the saliva and the level of malondialdehyde in gingivitis, it is possible to estimate the functional condition of parodontium, and the examined parametres can be considered as biochemical markers of its functional condition. The aim of this paper was to examine activity of alanine aminotransferase, aspartate aminotransferase, gamma glutamyl transferase, lactate dehydrogenase and the level of malondialdehyde in the saliva of children affected with gingivitis, as well as the values of the mentioned parametres in relation to the level of the inflammation of gingiva.

METHODS

The research included 120 children at the age of 12.2 with permanent dentition. Löe and Silness gingival index was used to estimate the condition of gingiva, based on which the childen were classified into four groups: the children with healthy gingiva (the control groups), the children with mild, moderate and severe inflammation of gingiva (the study group). Enzymes of the saliva were determined by the use of original tests and measured by the autoanalyser (Bio Systems A25, Spain). A modified method with tiobarbituric acid was used to determine malondialdehyde in nonstimulated mixed saliva.

RESULTS

The results of the examined enzyme activity and the level of malondialdehyde in the saliva of the study groups showed statistically considerably higher values for the level of malondialdehyde (p < 0.001), for the activity of aspartate aminotransferase and gamma glutamyl transferase (p < 0.01), as well as for alanine aminotransferase (p < 0.05) in comparison with the control group, whereas the activity of lactate dehydrogenase did not show a statistically significant increase. In relation to the level of the inflammation of gingiva, the results of the examination of the enzyme activity in the study groups showed statistically significantly higher values in the group with severe inflammation in comparison with those with mild, as well as the moderate inflamatiory, except for the gamma glutamyl transferase, and in the group with moderate inflammation compared to that with the mild one, except for alanine aminotransferase. The results of the examination of the level of malondialdehyde in the saliva of the study groups did not show a statistically significantly increase in relation to the level of the inflammation of gingiva.

CONCLUSION

There is a higher level of alanine aminotransferase, aspartate aminotransferase, gamma glutamyl transferase and lactate dehydrogenase enzyme activity together with the higher level of malondialdehyde in the saliva of children with gingivitis in comparison with the activity of the same enzymes and the level of malondialdehyde in the saliva of children without gingivitis. The activity of the examined enzymes in the saliva of children with gingivitis increases in relation to the intensity of the pathological process, whereas the level of malondialdehyde shows no significant difference in relation to the level of the inflammation of gingiva.

Oxidative stress parameters as possible urine markers in patients with diabetic nephropathy

OBJECTIVE

Reactive oxygen species play a crucial role in the pathogenesis of diabetic nephropathy (DN). The present study was performed to assess oxidative stress parameters-thiobarbituric acid reactive substances (TBARS), reactive carbonyl derivates (RCDs), and total sulfhydryl groups (TSHGs)-in serum and urine of patients with DN.

METHODS

All parameters were determined in patients with type 2 and type 1 diabetes mellitus and microalbuminuria (DMT2-MIA, DMT1-MIA, respectively) and patients with type 2 diabetes mellitus and macroalbuminuria (DMT2-MAA) compared to healthy controls.

RESULTS

Serum and urine TBARS levels were higher in all patients with DN and microalbiminuria compared to the control group. RCD levels significantly increased in serum of patients with DMT2 relative to the controls as well as in urine of patients with DMT2-MAA and DMT1-MIA. In all groups of patients, TSHGs decreased in serum but not in urine of patients with DMT2-MAA.

CONCLUSION

Urine TBARS, RCDs, and TSHGs could be proposed as possible markers for oxidative damage of kidney in DN.

Ethanol inhibitory effect on rat kidney brush border aminopeptidases

BACKGROUND/AIM

Confusing data have been reported about the effect of ethanol or its metabolic products on blood pressure. The pressor agent, angiotensin II (Ang II), is found to be susceptible to degradation by different enzymes known as angiotensinases. We have studied the effects of ethanol and L-NAME, an inhibitor of nitric oxide synthase, consumption on rat serum and kidney ectoenzymes: aminopeptidase N (APN) and aminopeptidase A (APA).

METHODS

Enzymatic activity of both enzymes was determined spectrophotometrically in serum and 10% homogenates of the rat kidney cortex using appropriate chromogenic substrates.

RESULTS

After 2 weeks of treatment with ethanol and L-NAME, blood urea and creatinine levels were significantly increased. The activities of APN (EC 3.4.11.2) and APA (EC 3.4.11.7) were reduced in serum as well as in kidney tissue during this period. L-NAME significantly attenuated activities of both enyzmes. Ethanol and L-NAME given simultaneously did not have an additional effect on the activity of investigated enzymes.

CONCLUSION

Hypertension caused by chronic ethanol treatment as well as L-NAME administration could be associated with the reduction of APN and APA activity. Possible ethanol- and L-NAME-mediated inhibition of angiotensins degrading aminopeptidases could potentiate their effects on blood pressure.

Dietary curcumin does not protect kidney in glycerol-induced acute renal failure

Generation of reactive oxygen species significantly contribute to the pathogenesis of renal injury induced by myoglobin release. The present study was performed to investigate the effects of dietary curcumin, a natural antioxidant isolated from plant Curcuma longa, in an experimental model of myoglobinuric acute renal failure. Rats received curcumin at an oral dose of 100mg/kg/day for 30 days. Renal injury was induced with injection of hypertonic glycerol (10 ml/kg 50% solution) in hind limb muscle with blood urea of 57.8+/-7.2 vs. 7.72+/-1.03 mmol/l and serum creatinine of 444.4+/-61.3 vs. 51.8+/-10.6 micromol/l, in glycerol-induced acute renal failure (ARF) vs. control rats, respectively. After 48 h rats were sacrificed and thiobarbituric acid reactive substance (TBARS), glutathione, carbonyl content and kidney cortex brush border peptidase activities were determined in serum, kidney and liver. Rats that received curcumin in addition to glycerol had significantly lower TBARS in serum but not in kidney and liver. Carbonyl content in kidney and liver was significantly elevated in curcumin and glycerol treated rats and improved in animals treated with curcumin and glycerol together. The activities of kidney cortex enzymes, aminopeptidase N, angiotensinase A and dipeptidyl peptidase IV, were reduced in glycerol as well as in curcumin treated rats. The results obtained in this study provided additional evidence that despite its limited antioxidant activity curcumin did not protect kidney in myoglobinuric model of ARF.

Role of quercetin on hepatic urea production in acute renal failure

Acute renal failure (ARF) is a serious damage of renal function induced by various nephrotoxic drugs, ischemia, bilateral urethral obstruction, trauma and unilateral nephrectomy. Dramatic clinical syndrome, azotemia, develops as a result of hypovolemia, oliguria, reduced glomerular filtration and acidosis. In addition to classic medications recent studies give more attention to beneficial effect of natural plant products as bioflavonoids. We have studied the influence of bioflavonoid, quercetin, on hepatic urea production in glycerol induced ARF in the rats. Male Sprague Dawley rats were used in the experiment. The value of urea production in the liver was determined by measuring of liver arginase activity, the terminal enzyme of urea cycle. Arginase activity was increased (p < 0.01) as well as urea level (p < 0.001) 48 h after glycerol administration. Pretreatment by quercetin suppressed the arginase activity in the liver (p < 0.05) and plasma levels of urea (p < 0.01). So, we have concluded that quercetin may be beneficial in glycerol induced ARF.

Selenium-dependent GSH-Px in erythrocytes of patients with hypertension treated with ACE inhibitors

This study is aimed at examining whether essential arterial hypertension (HTN) or ACE inhibitors have any effect on erythrocyte selenium (Se)-dependent and Se-non-dependent glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) activity. Eleven patients with HTN (2 men and 9 women) and 9 healthy volunteers were included in this study after clinical examination and laboratory investigation. The activities of all three enzymes were determined and then the patients were assigned to receive ACE inhibitor therapy consisting of captopril, 25 to 50 mg daily, or enalapril, 10 to 40 mg daily. After 1 year, the determination of antioxidant enzymes was repeated. Our results showed that the initial values of Se-dependent GSH-Px in patients treated with ACE inhibitors were significantly lower (19.60 +/- 3.50 microM NADPH/min(-1)/mgHb(-1)) compared with the controls (28.64 +/- 4.93 microM NADPH/min(-1)/mgHb(-1); p < 0.001), whereas the activity of Se-non-dependent GSH-Px was significantly enhanced (13.55 +/- 1.46 microM NADPH/min(-1)/mgHb(-1); p < 0.001) compared with the control group (9.44 +/- 0.81 microM NADPH/min(-1)/mgHb(-1); p < 0.001). ACE inhibitors did not significantly change the activity of Se-dependent GSH-Px or Se-non-dependent GSH-Px. No significant alteration was observed in SOD activity.

The possible importance of the cation-binding site for the oxidative modification of liver 5'-nucleotidase

The oxidative damage of proteins and lipid peroxidation of membrane lipoproteins has already been described as a possible pathogenic mechanism for liver injury. The aim of the present study was to examine the mechanism that could be responsible for the oxidative modification of rat liver 5'-nucleotidase during exposure to different free radical generating systems: FeCl2/ascorbate, xanthine/xanthine oxidase and H2O2. The level of lipid peroxidation products malondialdehyde (MDA), as well as the level of protein carbonyl groups formation was measured in cells and extracellular medium. The activity of 5'-nucleotidase was linearly decreased in both hepatocytes and extracellular medium after exposure to the FeCl2/ascorbate system indicating that the possible mechanism for oxidative modification could be a metal-binding site of the enzyme. In xanthine/xanthine oxidase system the enzyme activity of hepatocytes had decreased in hepatocytes but increased in the extracellular medium indicating that proteolysis of membrane proteins could he responsible for enzyme release in the extracellular medium. When hepatocytes were exposed to a H2O2 free-radical generating system, the activity of 5'-nucleotidase tended to be decreased in cells and decreased in extracellular medium too, indicating that H2O2 could be less reactive in producing an oxidative modification of the enzyme. In order to support the hypothesis that the cation-binding site can be responsible for oxidative modification of the enzyme, the isolated hepatocytes were preincubated with a Ca(2+)-channel blocker (Verapamil) and then exposed to different radical-generating systems. Verapamil had only a slight effect in potentiating the inhibition in the FeCl2/ascorbate system. This probably means that the cellular cation flux and cation binding may be included as a vulnerable site with the greatest importance in the oxidative modification of 5'-nucleotidase.

Low catalase activity in rats with ureteral ligation: relation to lipid peroxidation

Progression of some renal diseases is characterized by generation of reactive oxygen metabolites that are also involved in the pathophysiology of obstructive nephropathy. Catalase activity and lipid peroxidation were investigated in rats with unilaterally (UUL) and bilaterally ligated ureters (BUL). Forty-eight hours after ligation, the animals were sacrificed, and enzyme activity as well as the malondialdehyde (MDA) concentration were measured in the plasma, kidneys and livers. The activity of catalase was significantly reduced in the plasma of the BUL rats and in the kidneys of both investigated groups. In the liver, catalase activity was decreased only in the BUL group. The MDA concentration in the plasma and kidneys of the BUL rats was significantly increased while in the liver it remained unchanged. These results suggest that lipid peroxidation in the induced uremic state could be responsible for catalase inactivation.

Changes of lipid peroxides and antioxidative factors levels in blood of patients treated with ACE inhibitors

In 14 patients (4 males and 10 females) with systemic hypertension plasma and erythrocyte lipid peroxides, plasma and erythrocyte catalase activity, plasma glutathione S-transferase (GST) activity, blood reduced glutathione (GSH) content and erythrocyte oxidant stress were investigated. All parameters were performed after clinical examination and then the patients were assigned to receive ACE inhibitor therapy, captopril (25-50 mg given twice per day) or enalapril (10-40 mg given twice per day). After six months the determination of lipid peroxides and antioxidative factors was repeated. At the beginning of the study both treated groups showed significantly higher plasma lipid peroxides compared to the control group. Both used ACE inhibitors produced significant decrease of plasma lipid peroxides after six months. Blood GSH content was also significantly higher in both patient groups before the treatment compared to the controls. Neither captopril nor enalapril produced any significant effect on GSH. Initial values of plasma GST activity in the patients were similar to the control group and did not significantly change after six month treatment. The patients assigned to receive enalapril showed significantly enhanced initial plasma catalase activity according to the controls. After six months treatment both ACE inhibitors significantly decreased plasma catalase activity. Erythrocyte lipid peroxides, erythrocyte catalase activity and oxidant stress of erythrocytes in both groups studied neither differ significantly at initial time of investigation according to the control group nor during or after six month treatment.

[Dental pulp in carious teeth]

Various etiologic causes lead to dental pulp changes ranging from inflammation to necrosis. The most frequent changes, however, are caused by bacterial activity and toxins from carious process. According to the opinion of various authors and on the basis of our investigations the conclusion can be made that all the forms of dental pulp changes can be developed as the sequela of the disease of supporting apparatus. Pathohistologic examination of dental pulp of cariously damaged teeth showed that the occurred changes are mostly the sequela of inflammation and regressive and progressive changes are found as well.