Gold nanoparticle/polymer nanocomposite for highly sensitive drug-DNA interaction.

The interaction of the anticancer drug mitomycin C (MC) and DNA immobilized on gold a nanoparticle/polyvinylferrocenium (AuNP/PVF(+)) coated electrode is presented. This is the first attempt to prepare a biocompatible nanoparticle/redox polymer composite in a one-step and easy electropolymerization procedure and then use the coated electrode for MC-DNA interaction. The prepared electrode exhibits high sensitivity for the investigation of drug-DNA interaction.

Erythropoietin exerts neuroprotection in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-treated C57/BL mice via increasing nitric oxide production.

Erythropoietin (EPO), produced by the kidney and fetal liver, is a cytokine-hormone that stimulates erythropoiesis under hypoxic conditions. It has been shown that EPO is produced in the central nervous system and its receptor is expressed on neurons. Since EPO has neuroprotective effects in vitro and in vivo against brain injury, we investigated the effect of EPO treatment on locomotor activities of animals, survival of nigral dopaminergic neurons and nitrate levels in substantia nigra and striatum in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced animal model of Parkinsonism in C57/BL mice. Our findings suggest that EPO has protective and treating effect in MPTP-induced neurotoxicity in this mouse model of Parkinson's Disease via increasing nitric oxide production.

Effect of anticoagulants on plasma homocysteine determination.

BACKGROUND: Waiting temperature before centrifugation and anticoagulants used, markedly effect total homocysteine concentrations. The aim of this study was to investigate the effect of different anticoagulants and temperature on plasma homocysteine levels. METHODS: We studied total homocysteine concentrations in 23 healthy subjects. Blood was drawn in K(3)EDTA, sodium citrate- or sodium fluoride-containing tubes, and kept at 0 degrees C or 22 degrees C for 3 h. Total homocysteine measurements were performed with fluorescence polarization immunoassay (FPIA) method. We compared all results with baseline EDTA values (samples put on crushed ice and centrifuged immediately) recommended in literature for reference handling. RESULTS: At 22 degrees C, the tubes containing sodium citrate and sodium fluoride showed significantly higher total homocysteine concentrations than their respective baseline values (p=0.000). However, sodium fluoride tubes were not significantly different than baseline EDTA levels. Waiting 3 h at 0 degrees C did not effect sodium citrate and EDTA plasma total homocysteine concentrations when compared to baseline EDTA, but sodium fluoride-containing plasma levels were significantly decreased (p=0.000). CONCLUSIONS: According to our results, the most available and practical temperature and anticoagulant for total homocysteine determination is sodium fluoride at room temperature up to 3 h.

Diagnostic usefulness of tumour marker levels in pleural effusions of malignant and benign origin.

Pleural effusion is a common diagnostic problem. The analysis of serum and body fluids for tumor markers has been intensively applied to clinical diagnosis. The aim of the present study was to determine the usefulness of simultaneous quantification of carbohydrate antigen 19.9, carbohydrate antigen 125, neuron specific enolase, mucinous-carcinoma-associated antigen, and ferritin in samples of pleural fluids in the malign pleural effusion and its differentiation from benign effusions. A total of 61 pleural effusions were collected from the patients, who were subjected either to simple needle aspiration or to tube drainage for the diagnosis of pleural effusion. Tumor markers were determined in benign patient groups with nonspecific pleurisy, tuberculous pleurisy, empyema, congestive heart failure and in malignancy groups consisting of adenocarcinoma, small cell lung carcinoma, mesothelioma, epidermoid lung cancer. The tumor markers CA-19.9, CA-125, NSE, and ferritin levels were quantified by the sandwich assay using the streptavidin technology of ELISA in an ES-300 Boehringer-Mannheim analyser. MCA was measured by employing a two-side solid phase EIA method. MCA measurements were done by the Cobas-Core. For all patients, the effusions correctly or incorrectly identified by the different procedures as being malignant or nonmalignant are defined as true positive, false positive, true negative, and false negative, the term 'positive' referring to histologically proven malignant pleural effusion while nonmalignant effusions are referred to as 'negative'. Therefore, sensitivity, specificity, positive predictive value, and negative predictive value were defined as diagnostic parameters. The cut-off values calculated were 352 U/ml for CA-125, 54 U/ml for CA-19.9, 555 for ferritin, 11.1 for MCA and 8.7 for NSE. In our study, the highest sensitivity is found to be MCA with 100%; specificity, CA-19.9 with 97%; PPV, CA-19.9 and MCA with 95% and NPV, MCA with 100%. Our data imply that the co-measurement of MCA+CA-19.9+CA-125 levels may further improve their diagnostic value in malignant pleural effusion compared with that of each tumour marker alone and may be useful in distinguishing malignant from benign pleural effusions.

Urinary thioether excretion and erythrocyte glutathione S-transferase activities in smokers and patients with squamous-cell laryngeal cancer.

Various biomarkers exist for assessment of exposure to cigarette smoke. The aim of this study is to evaluate whether the urinary thioethers (UT) and erythrocyte glutathione S-transferase (GST) enzyme activities can be used as a biomarker or indicator of a higher risk of laryngeal cancer among smokers. In the present study, the concentration of UT and erythrocyte CST activities were measured in a sample of 84 subjects: controls, smokers, and smokers with squamous-cell carcinoma of the larynx (SLC). For this study, cases were restricted to men, since the number of women was not sufficient for statistical comparisons. Smoking significantly increased UT levels without a marked change in GST activity. However, in SLC smoking patients both UT levels and GST activity were significantly elevated. The use of nonspecific UT levels with GST activity determination seems to be a reliable indicator for the presence of laryngeal cancer in smokers.

Possible role of glutathione in prevention of acetaminophen-induced hepatotoxicity enhanced by fish oil in male Wistar rats.

It has been reported that fish oil protects the rat liver against acetaminophen (APAP) induced toxicity; however, this finding is controversial. The present study was undertaken to investigate the effects of fish oil-enriched diet on APAP-induced liver injury in Wistar rats. Rats were fed a diet supplemented with either 8% fish oil or 8% corn oil, or standard rat feed for 6 wk. After an overnight fast, rats in each group were given either 2 g/kg APAP or saline orally. Our findings showed that APAP increased serum alanine aminotransferase (ALT) and that this rise was potentiated in the presence of dietary fat. Further fish oil ingestion increased the glutathione (GSH) content in rat liver; however, this was not effective in protecting liver from APAP-induced toxicity. Data suggest that GSH may be necessary to detoxify APAP metabolites, which are known to induce hepatotoxicity but are increased by dietary fat.

Cytoprotective effects of trimetazidine in carmustine cholestasis.

Carmustine [1 ,3-bis(2-chloroethyl)-1-nitrosurea (BCNU)] is an antitumour agent, however, its usefulness has been limited by a side effect; which involves pericholangitis and intrahepatic cholestasis. The primary effects of cholestasis is well known; bile flow retention, intracellular Ca++ accumulation and acidosis although it may lead to hepatotoxicity by dose-dependent manner. Recent studies provide evidence that lipoperoxidation (LPO) and alterations in the antioxidant system may significantly contribute to BCNU induced hepatotoxicity. Trimetazidine, (1-[2,3,4-Trimethoxy-benzyl] piperazine HCl; TMZ) introduced as an antianginal compound, is found to exhibit various cytoprotective features by preserving cellular ATP levels, limiting intracellular acidosis and inorganic phosphate as well as Na+ and Ca++ accumulation in ischemic cardiac injury. No study was undertaken to investigate the cytoprotective role of TMZ in cholestatic injury till today; therefore we initiated this study to investigate if its cytoprotective features also exhibit in the liver and to characterize further the cholestatic response to BCNU administration. Male rats were randomly seperated to control (CONT) (n = 15), BCNU administered (BCNU) (n = 16) and BCNU+TMZ administered (BCNU+TMZ) (n = 12) groups. The control rats received a single dosage of 2 ml/kg of corn oil (i.p.) while the BCNU group received a single dosage of BCNU (20 mg/kg, i.p.) in corn oil. In the BCNU + TMZ group 2,5 mg/kg/day (i.p.) of TMZ was administered for three days. This group also received BCNU (20 mg/kg, i.p.) in corn oil, 12 hours after the initial dose of TMZ. The cholestatic effect of BCNU was monitored by stasis markers such as ALP, GGT and total bilirubin levels. Hepatic TBARS analysis was determined with the modified method of OKHAWA et al. based on the reaction of lipid peroxides with thiobarbituric acid. Oxidized (GSSG) and reduced (GSH) glutathione levels were measured by the modified enzymatic recycling method of TEARE et al. Statistical tests were performed using Kruskal Wallis one-way Anova test and posthoc analysis by Newman-Keuls test. The BCNU group and the BCNU + TMZ group showed significant increases (p = 0.029) in hepatic TBARS levels compared to the CONT group; however the difference between the BCNU and BCNU + TMZ groups in regard to TBARS was not significant. BCNU and BCNU + TMZ groups manifested a significant decrease (p = 0.0005) in GSH levels as compared to controls. GSH/GSSG ratios in the BCNU and BCNU + TMZ group also manifested a significant decrease (p = 0.0013) as compared to the CONT group. TMZ administration caused a significant increase in total GSH levels (p = 0.0026) in BCNU + TMZ group when compared to the BCNU group. Our results support the hypothesis that BCNU induced cholestasis partly involves LPO revealed by the distinct increase in the content of TBARS in the liver after BCNU administration. BCNU is a potent inhibitor of GSSG reductase altering the preservation of the thiol redox balance in the system. As a result, supranormal concentrations of intracellular GSSG would accumulate in the hepatocyte and the extrusion of this oxidized compound would require active transport leading to ATP hydrolysis. This would deplete the energy stores of the cell which would accelerate further the possible prooxidant status. Although administration of TMZ did not provoke any significant alterations in LPO, it preserved the total GSH levels of the cell probably by improving the energy status of the cell by protection of ATP-producing processes at the mitochondrial level and provision of the necessary substrates for GSH synthesis. This protective role in the antioxidant system normalizes the altered GSH levels by BCNU and hence proposes TMZ to be a promising agent in the cholestatic injury.

Could conductivity be used as a parameter in urinalysis?

Conductivity is a non-linear function of electrolyte concentration in solutions and could be used as an indirect method. The aim of this study was to determine the feasibility of urine conductivity measurement, which is a simple, cheap and not time consuming method, in the evaluation of renal functions. Seventy-two patients whose primary diseases were not taken into consideration were enrolled in this study. First morning urine specimens were obtained from all the patients and evaluated for osmolality, conductivity, pH, specific gravity, protein, creatinine, urea, uric acid, glucose, sodium, potassium, chloride, inorganic phosphate and calcium levels. There was a significant positive relation between osmolality and creatinine, urea, sodium, potassium, chloride, inorganic phosphate, uric acid, conductivity and specific gravity. Conductivity was also determined to be positively related to osmolality (r: 0.390, p < 0.01), sodium (r: 0.326, p < 0.01) and uric acid (r: 0.345, p < 0.01). The patients were grouped as those with a urine osmolality of less or more than 290 m Osm/kg. H2O (group A and B respectively). Urine conductivity was 6.84 +/- 5.35 (0.16-23.2) mScm-1 in group A and 10.6 +/- 5.25 (0.12-192) mScm-1 in group B. The difference was statistically significant (p = 0.005). When the spectrum of conductivity values were evaluated separately in each group, 74% of the patients in group A and 33.9% of the patients in group B were determined to have a conductivity level of less than 7.338 mScm-1. In conclusion, urine conductivity has a positive relation with osmolality. In addition, while osmolality and specific gravity are effected by many non-electrolyte molecules, conductivity is only related to sodium and uric acid concentrations. In addition, urine osmolality and conductivity levels could be used to interpret the concentration of uncharged glucose molecules. These results suggest that conductivity could be used as a parameter in routine urinalysis.

Effect of simvastatin therapy on blood and tissue ATP levels and erythrocyte membrane lipid composition.

3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase inhibitors decrease mevalonate and subsequently cholesterol synthesis competitively. Mevalonate is also the precursor of ubiquinone. Ubiquinone is an important component of electron transport chain. We therefore investigated the effect of simvastatin on rat blood and tissue ATP concentrations and the lipid composition of red blood cell membranes after 4 weeks of therapy. Significant reductions in rat plasma cholesterol, triglyceride, and blood ATP concentrations were detected. Tissue ATP levels were not affected. Membrane phospholipids increased, while cholesterol and the cholesterol to phospholipid ratio decreased (P < 0.05). A positive correlation between the plasma cholesterol concentration and the cholesterol to phospholipid ratio was noted (P < 0.05, r = 0.851). Our results show that HMG-CoA reductase inhibitors change the composition and probably also the functions of cell membrane lipids and blood ATP concentration.

Erythrocyte membrane Na+,K+ ATP ase activity can be a marker of liver histopathology.

Erythrocyte membrane Na+,K+: Ca2+ ATP ase activities, cholesterol (CH) phospholipid (PL) composition and erythrocyte glutathione (GSH) contents were determined in controls, in patients with chronic active hepatitis and liver cirrhosis. NA+,K+ ATP ase activities were significantly (P < 0.0001) less in patients with chronic active hepatitis and liver cirrhosis (n = 8, 0.102 +/- 0.02 mumol P/mg protein/hour; n = 8, 0.081 +/- 0.02 mumol P/mg protein/hour) than in controls (n = 10, 0.219 +/- 0.05). Histopathological analysis of liver sections obtained from patients with chronic active hepatitis (n = 3) and liver cirrhosis (n = 2) correlated well with erythrocyte biochemical findings. There was a significant negative correlation between Na+,K+ ATP ase activity and portal fibrosis (P < 0.05, r = -8680). However, further experiments performed on larger study populations are needed to better elucidate this correlation. Therefore, NA+K+ ATP ase activity measurement can be reliable assessment of liver fibrosis.

The effect of interferon therapy on erythrocyte membrane Na+,K+ ATP activity in patients with chronic hepatitis B and C virus infections.

In order to evaluate the effect of alpha interferon on erythrocyte membrane Na+,K+ ATPase (EC 3.6.1.37) activity, 10 patients with chronic hepatitis B virus (HBV) infection and 8 patients with chronic hepatitis C virus (HCV) infection were investigated. Erythrocyte membrane Na+,K+ ATPase activity was determined in controls and in patients with HBV and HCV infection. Na+,K+ ATPase activity was significantly less in untreated patients with (HBV) infection (n = 20; 0.134 +/- 0.073 mumol of phosphate produced per milligram of protein per hour) and (HCV) infection (n = 11; 0.144 +/- 0.049) when compared to the controls (n = 10; 0.219 +/- 0.055). Among these subjects patients were treated with interferon and following treatment, significant elevation of Na+,K+ ATPase activity was seen in patients with HCV (n = 8; 0.183 +/- 0.044; P = 0.049) and HBV (n = 10, 0.213 +/- 0.095, P = 0.0069) infections when compared with the pre-treatment values (n = 8; 0.152 +/- 0.050) and (n = 10, 0.131 +/- 0.083), respectively. Normalization of serum alanin amino transferase levels (ALT) at treatment cessation was seen in 8 of 10 (%80) HBV infected patients of whom 2 of 8 (%25) had sustained ALT responses within three months after the end of treatment. In HCV infected patients 1 of 8 (%12.5) had sustained response following treatment. At the end of treatment, although Na+,K+ ATPase was restored in both of the patients groups, relative changes in enzyme activity in relation to relative reduction in ALT levels as a response to IFN therapy were not correlated.