Protease Activated Receptor-2 Contributes to Heart Failure

Heart failure is a major clinical problem worldwide. Previous studies have demonstrated an important role for G protein-coupled receptors, including protease-activated receptors (PARs), in the pathology of heart hypertrophy and failure. Activation of PAR-2 on cardiomyocytes has been shown to induce hypertrophic growth in vitro. PAR-2 also contributes to myocardial infarction and heart remodeling after ischemia/reperfusion injury. In this study, we found that PAR-2 induced hypertrophic growth of cultured rat neonatal cardiomyocytes in a MEK1/2 and p38 dependent manner. In addition, PAR-2 activation on mouse cardiomyocytes increased expression of the pro-fibrotic chemokine MCP-1. Furthermore, cardiomyocyte-specific overexpression of PAR-2 in mice induced heart hypertrophy, cardiac fibrosis, inflammation and heart failure. Finally, in a mouse model of myocardial infarction induced by permanent ligation of the left anterior descending coronary artery, PAR-2 deficiency attenuated heart remodeling and improved heart function independently of its contribution to the size of the initial infarct. Taken together, our data indicate that PAR-2 signaling contributes to the pathogenesis of hypertrophy and heart failure.     

Influence of Nitrate and Sulfate on the Anaerobic Treatment of Pharmaceutical Wastewater

Anaerobic treatment of wastewater from the pharmaceutical industry, which contained about 3.2 g/L of sulfate, was carried out in an Upflow Anaerobic Sludge Blanket (UASB) reactor. After a startup period of 120 days, a chemical oxygen demand (COD) removal efficiency of more than 90 % was obtained along with an organic loading rate (OLR) of 1.5 g COD/(L day). During the same period, the sulfate removal was about 90 %. However, the performance of the reactor was affected when the loading rate was increased to 2.09 g COD/(L day). It was found that the accumulation of sulfides, combined with a decrease in the pH, affected the reactor performance. In batch reactor studies with pharmaceutical wastewater it was observed that methane production began only after the initiation of nitrate consumption. The denitrification process can inhibit sulfate reduction at high nitrate concentrations, but compared to reactors without nitrate, the sulfate reduction process and sulfide formation were quickly initiated at low nitrate concentrations. The methanogenic activity was however affected by the presence of more than 2 g/L of sulfate.     

Fluidized bed design parameters affecting novel lactic Acid downstream processing.

Lactic acid purification was directly done from fermentation utilizing a fluidized bed column refilled with a strong anionic exchange resin. The purpose of this work was to study the influence of two important design parameters, bed-diameter (D) and bed-height (H), in the lactic acid binding and elution capacity of the matrix. By changing the settled bed height from 2.5 to 5 cm for each diameter of column analyzed it was possible to obtain an 50% increase in the binding capacity of the resin in all experiments. This fact was attributed to a higher contact time between the culture broth and the anionic resin produced by the increase of back mixing and lactic acid residence time.     

Metabolic reduction of chromium,as related to its carcinogenic properties

At variance with Cr(III), Cr(VI) compounds easily cross cell membranes and exert genotoxic effects. No metabolic oxidation of Cr(III) could be detected, whereas Cr(VI) reduction was observed in the presence of body fluids and subcellular fractions of various tissues from several animal species. The differential efficiency of this process may account for the selection of target tissues in Cr(VI) carcinogenesis. For instance, reduction by saliva and gastric juice may explain a lack of carcinogenicity by the oral route; reduction inside erythrocytes may explain a lack of carcinogenicity at a distance from administration sites; reduction by the epithelial-lining fluid of terminal airways and by alveolar macrophages may be consistent with the occurrence of thresholds in lung carcinogenesis. Liver preparations displayed the top efficiency in reducing Cr(VI), whereas skeletal muscle, i.e., a typical target in experimental Cr(VI) carcinogenesis, had no detectable activity. Bronchial tree and peripheral lung parenchyma preparations from almost 100 individuals reduced Cr(VI) to a variable extent. The efficiency of lung parenchyma and of isolated alveolar macrophages was enhanced in cigarette smokers. In rats, Cr(VI) reduction by lung preparations was significantly stimulated by the repeated i.t. instillation of Cr(VI) itself. Among the electron donors (chiefly GSH) and enzymatic mechanisms responsible for the intracellular Cr(VI) reduction, such as cytochrome P-450 reductase, glutathione redactase, and aldehyde oxidase, an important role can be ascribed to cytosolic DT diaphorase activity, usually catalyzing a 2-electron reduction.     

Unusual DNA structures at the integration site of an HIV provirus

Supercoiled pHXBc2 DNA (containing the genome of the human immunodeficiency virus type 1 and human sequences) migrated more slowly than linear DNA in native and ethidium bromide agarose gel electrophoresis at 4.5 volts/cm, suggesting the presence of unusual DNA structures. S1 nuclease analysis of pHXBc2 revealed two S1 hypersensitive sites. Site I was located within a 25 bp direct repeat in host DNA 0.6 kB upstream from the 5' LTR. Site II was mapped 0.2 kB upstream from the vif gene start site. Sequence analysis showed that Site I sequences could assume different unusual DNA structures, whereas sequences at Site II could assume either slipped or H-DNA forms. Unusual DNA structures in host DNA may be associated with active chromatin regions and may favor proviral integration.     

Binding of beta-galactosidase from rat epididymal fluid to the sperm surface by high-affinity sites different from phosphomannosyl receptors.

beta-Galactosidase, known to be secreted by epithelial cells lining the rat epididymal duct, binds to the surface of spermatozoa from the caudal region with high affinity and in a saturable form. The binding was not inhibited by mannose-6-phosphate, but was inhibited by fructose phosphate derivatives, a peculiarity previously demonstrated for the membranes of epididymal tissue. Fructose phosphate derivatives released 55% of beta-galactosidase activity from the spermatozoa. These results suggest that in the epididymis there is a special transport system for hydrolases, which could be involved in the secretion of enzymes destined for spermatozoa. This transport would require receptors that recognize sugar ligands other than mannose-6-phosphate. These receptors were present in the epididymal tissue and on the sperm surface.     

Prevention by N-acetylcysteine of benzo[a]pyrene clastogenicity and DNA adducts in rats

The daily i.t. administration of benzo[a]pyrene (BP) to Sprague-Dawley rats, for 3 consecutive days, did not cause any toxicity or clastogenicity in bone marrow cells, as evaluated by monitoring the ratio of polychromatic to normochromatic erythrocytes and the frequency of micronucleated polychromatic erythrocytes. However, BP produced a considerable enhancement of binucleated and micronucleated pulmonary alveolar macrophages, as well as a significant increase in polymorphonucleates recovered by bronchoalveolar lavage. These effects were prevented by administering the thiol N-acetylcysteine (NAC) by gavage 5 h before each BP instillation. In addition, the i.t. treatment with BP resulted in the formation of BP diolepoxide (BPDE)-DNA adducts in lungs and liver, as assessed by synchronous fluorescence spectrophotometry, with fluorescence peaks of similar magnitude in the 2 tissues. Pretreatment with NAC by gavage completely prevented BPDE adducts to liver DNA and significantly decreased those to lung DNA.