Application of the buccal micronucleus cytome assay and analysis of PON1Gln192Arg and CYP2A6*9(−48T>G) polymorphisms in tobacco farmers

Tobacco is a major Brazilian cash crop. Tobacco farmers apply large amounts of pesticides to control insect growth. Workers come into contact with green tobacco leaves during the tobacco harvest and absorb nicotine through the skin. In the present study, micronucleus frequency, cell death, and the frequency of basal cells were measured in tobacco farmers using the buccal micronucleus cytome assay (BMCyt), in parallel with measurement of blood butyrylcholinesterase (BChE) and nicotine levels. Polymorphisms in PONIGln192Arg and CYP2A6*9(?48T>G) were evaluated to verify the relationship between genetic susceptibility and the measured biomarkers. Peripheral blood and buccal cell samples were collected from 106 agricultural workers, at two different crop times (during pesticide application and leaf harvest), as well as 53 unexposed controls. BMCyt showed statistically significant increases in micronuclei, nuclear buds, and binucleated cells among exposed subjects in differentiated cells, and in micronuclei in basal cells. In addition, the exposed group showed higher values for condensed chromatin, karyorrhectic, pyknotic, and karyolitic cells, indicative of cell death, and an increase in the frequency of basal cells compared to the unexposed control group. A slight difference in mutagenicity using the BMCyt assay was found between the two different sampling times (pesticide application and leaf harvest), with higher micronucleus frequencies during pesticide application. Elevated cotinine levels were observed during the leaf harvest compared to the unexposed controls, while BChE level was similar among the farmers and controls. PONIGln192Arg and CYP2A6*9(?48T>G) polymorphisms were associated with DNA damage induced by pesticides and cell death. Environ. Mol. Mutagen., 2012. © 2012 Wiley Periodicals, Inc.     

The distribution of erythrocyte phospholipids in hereditary spherocytosis demonstrates a minimal role for erythrocyte spectrin on phospholipid diffusion and asymmetry

In the human erythrocyte membrane phosphatidylcholine and sphingomyelin reside mainly in the outer leaflet, whereas the aminophospholipids, phosphatidylethanolamine and phosphatidylserine, are mainly found in the inner leaflet. Maintenance of phospholipid asymmetry has been assumed to involve interactions between the aminophospholipids and the membrane skeleton, in particular spectrin. To investigate whether spectrin contributes to maintaining the phospholipid transbilayer distribution and kinetics of redistribution, we studied erythrocytes from hereditary spherocytosis patients whose spectrin levels ranged from 34% to 82% of normal. The phospholipid composition and the accessibility of membrane phospholipids to hydrolysis by phospholipases were in the normal range. Spin-labeled phosphatidylserine and phosphatidylethanolamine analogues that had been introduced into the outer leaflet were rapidly transported at 37 degrees C to the inner leaflet, whereas the redistribution of spin-labeled phosphatidylcholine was slower. The kinetics of transbilayer movement of these spin-labeled phospholipid in all samples was in the normal range and was not affected by the level of spectrin. Although these erythrocyte membranes contained as little as 34% of the normal level of spectrin and were characterized by several physical abnormalities, the composition, distribution, and transbilayer kinetics of the phospholipids were found to be normal. We therefore conclude that spectrin plays, at best, only a minor role in maintaining the distribution of erythrocyte membrane phospholipid.     

Selective Na+/H+ exchange inhibition by cariporide reduces liver fibrosis in the rat

The aim of this study was to evaluate the effect of cariporide, a selective Na(+)/H(+) exchange inhibitor, on isolated and cultured hepatic stellate cells (HSCs) and in 2 in vivo models of rat liver fibrosis. Platelet-derived growth factor (PDGF)-induced HSC proliferation, evaluated by measuring the percentage of bromodeoxyuridine-positive cells, was significantly inhibited by cariporide, with a maximal effect at 10 micromol/L. Incubation with cariporide did not inhibit PDGF-induced extracellular-regulated kinase 1/2 (ERK1/2), Akt (a downstream component of the phosphatidylinositol [PI]-3 kinase pathway), and protein kinase C (PKC) activation but reduced PDGF-induced activation of the Na(+)/H(+) exchanger, with a maximal effect at 10 micromol/L. Rats treated with dimethylnitrosamine (DMN; 10 mg/kg) for 1 and 5 weeks received a diet with or without 6 ppm cariporide. Treatment with cariporide reduced the degree of liver injury, as determined by alanine aminotransferase (ALT) values, also when administered after the induction of hepatic damage. This was associated with reduced HSC activation and proliferation and reduced collagen deposition, as determined by morphometric evaluation of alpha-smooth muscle actin (SMA)/proliferating cell nuclear antigen-positive cells and percentage of Sirius red-positive parenchyma, respectively. Moreover, cariporide was also able to reduce alpha(1)I procollagen messenger RNA (mRNA) expression. Similar effects were observed in bile duct-ligated (BDL) rats. In conclusion, selective inhibition of the Na(+)/H(+) exchanger by cariporide may represent an effective therapeutic strategy in the treatment of hepatic fibrosis.     

Effects of dexamethasone on the growth and epidermal growth factor receptor expression of the OVCA 433 ovarian cancer cells.

We studied the correlation between dexamethasone (Dex) induced growth effects and modulation of epidermal growth factor receptor (EGFR) expression in OVCA 433 ovarian cancer cells. These cells express specific high and low affinity 125I-EGF binding sites and are growth stimulated by EGF. Dex exhibits mitoinhibitory effects by recruiting OVCA 433 cells in the G0-G1 phase of the cycle, but increases the number of both the high and the low affinity EGFR in a dose dependent manner. The maximal EGFR expression increase occurs after 24 h of Dex treatment consistently with Northern blot studies. The mitogenic activity of EGF in OVCA 433 cells is not affected by the presence of Dex. Moreover Dex growth inhibition occurs in JA1 cells, an ovarian cancer cell line which expresses unfunctional EGFR and which is unresponsive to EGF. Our results indicate that the Dex induced growth effects occur independently of EGFR expression.     

Influence of the timing of cardiac catheterization and the amount of contrast media on acute renal failure after cardiac surgery

Postoperative acute renal failure (ARF) is not uncommon after cardiac surgery and after angiography. However, limited information exists regarding the influence of the interval between cardiac catheterization and subsequent cardiac surgery and amount of contrast agent used during this procedure on the occurrence of postoperative ARF. Data for 423 consecutive adult patients who underwent elective cardiac surgery after cardiac catheterization were examined retrospectively. The influence of interval between cardiac catheterization and cardiac surgery on postoperative ARF (defined as postoperative serum creatinine > or =2 times baseline and >2 mg/dl and/or need for renal replacement therapy) was evaluated using multivariable logistic regression. ARF occurred in 24 patients (5.7%). Median time to angiography was 2 days (interquartile range 1 to 4.5), and median dose of contrast used was 1.36 ml/kg (interquartile range 1.12 to 1.69). Surgery on the day of cardiac catheterization was independently associated with increased risk of ARF (adjusted odds ratio 3.1, 95% confidence interval 1.1 to 8.8). This risk of ARF was highest in patients who underwent surgery on the same day as angiography and with a dose of contrast higher than median (14.6%) and lowest when surgery was delayed beyond 1 day of angiography and contrast dose was median or less (2.4%; adjusted odds ratio for same-day surgery and dose higher than median 4.2, 95% confidence interval 1.2 to 14.2). Cardiac surgery performed on the day of cardiac catheterization and higher dose of contrast agent used were both independently associated with increased risk of postoperative ARF. In conclusion, these findings suggest that delaying cardiac surgery beyond 24 hours of exposure to contrast agents (when feasible) and minimizing the use of these agents have significant potential to decrease the incidence of postoperative ARF in patients undergoing elective cardiac surgery.     

Is CA72-4 a Useful Biomarker in Differential Diagnosis between Ovarian Endometrioma and Epithelial Ovarian Cancer?

Background. Surgical excision of ovarian endometriomas in patients desiring pregnancy has recently been criticized because of the risk of damage to healthy ovarian tissue and consequent reduction of ovarian reserve. A correct diagnosis in cases not scheduled for surgery is therefore mandatory in order to avoid unexpected ovarian cancer misdiagnosis. Endometriosis is often associated with high levels of CA125. This marker is therefore not useful for discriminating ovarian endometrioma from ovarian malignancy. The aim of this study was to establish if the serum marker CA72-4 could be helpful in the differential diagnosis between ovarian endometriosis and epithelial ovarian cancer. Methods. Serums CA125 and CA72-4 were measured in 72 patients with ovarian endometriomas and 55 patients with ovarian cancer. Results. High CA125 concentrations were observed in patients with ovarian endometriosis and in those with ovarian cancer. A marked difference in CA72-4 values was observed between women with ovarian cancer (71.0%) and patients with endometriosis (13.8%) (P < 0.0001). Conclusions. This study suggests that CA72-4 determination can be useful to confirm the benign nature of ovarian endometriomas in women with high CA125 levels.