CB1 cannabinoid receptor antagonism: a new strategy for the treatment of liver fibrosis

Hepatic fibrosis, the common response associated with chronic liver diseases, ultimately leads to cirrhosis, a major public health problem worldwide. We recently showed that activation of hepatic cannabinoid CB2 receptors limits progression of experimental liver fibrosis. We also found that during the course of chronic hepatitis C, daily cannabis use is an independent predictor of fibrosis progression. Overall, these results suggest that endocannabinoids may drive both CB2-mediated antifibrogenic effects and CB2-independent profibrogenic effects. Here we investigated whether activation of cannabinoid CB1 receptors (encoded by Cnr1) promotes progression of fibrosis. CB1 receptors were highly induced in human cirrhotic samples and in liver fibrogenic cells. Treatment with the CB1 receptor antagonist SR141716A decreased the wound-healing response to acute liver injury and inhibited progression of fibrosis in three models of chronic liver injury. We saw similar changes in Cnr1-/- mice as compared to wild-type mice. Genetic or pharmacological inactivation of CB1 receptors decreased fibrogenesis by lowering hepatic transforming growth factor (TGF)-beta1 and reducing accumulation of fibrogenic cells in the liver after apoptosis and growth inhibition of hepatic myofibroblasts. In conclusion, our study shows that CB1 receptor antagonists hold promise for the treatment of liver fibrosis.     

Macro-scale topology optimization for controlling internal shear stress in a porous scaffold bioreactor

Shear stress is an important physical factor that regulates proliferation, migration, and morphogenesis. In particular, the homeostasis of blood vessels is dependent on shear stress. To mimic this process ex vivo, efforts have been made to seed scaffolds with vascular and other cell types in the presence of growth factors and under pulsatile flow conditions. However, the resulting bioreactors lack information on shear stress and flow distributions within the scaffold. Consequently, it is difficult to interpret the effects of shear stress on cell function. Such knowledge would enable researchers to improve upon cell culture protocols. Recent work has focused on optimizing the microstructural parameters of the scaffold to fine tune the shear stress. In this study, we have adopted a different approach whereby flows are redirected throughout the bioreactor along channels patterned in the porous scaffold to yield shear stress distributions that are optimized for uniformity centered on a target value. A topology optimization algorithm coupled to computational fluid dynamics simulations was devised to this end. The channel topology in the porous scaffold was varied using a combination of genetic algorithm and fuzzy logic. The method is validated by experiments using magnetic resonance imaging readouts of the flow field.     

Functionalization of cellulose-containing fabrics by plasma and subsequent metal salt treatments

In order to upgrade the UV-protection and antibacterial functional properties of cotton/polyester (80/20), cotton/linen (50/50) and linen/viscose-polyester (50/50) fabric blends, they were treated with different plasma gases (oxygen, air, and argon) followed by subsequent treatment with certain metal salts namely Zn-acetate, Cu-acetate, Al-chloride, and Zr-oxychloride. The obtained results show that the type of plasma gas, the kind of metal salt as well as the nature of the treated substrate play an important role in the extent of enhancing the demanded functional properties. Oxygen plasma treatment followed by Cu-acetate or Zn-acetate treatment gives the best UV-protection or antibacterial activity respectively, keeping other parameters constant. The surface morphology of some untreated and plasma-treated samples was also analyzed by SEM.     

Structural and electrical properties of paper-polyaniline composite

Conducting polymers have generated a great deal of interest because of their physical and chemical properties as well as their potential application in industry particularly in packaging applications. However one of short comings of most conducting polymer is that they are often formed as intractable films that are difficult to process. To overcome this problem we have incorporated conducting polymer, namely polyaniline into sheets of paper in order to create new composite material which combine the universal properties of paper product with the chemical and electrically conducting properties of the conducting polymer. Paper conducting polymer composite have been prepared by polymerizing aniline directly onto the paper sheet using ammonium peroxydisulfate (APS) as an oxidant at different temperatures. The prepared composite was characterized by FT-IR and SEM. The thermo-oxidative degradation was studied by thermo gravimetric analysis (TGA); electrical conductivities measurements of the composites were significantly increased over those of the precursor paper.     

OCRL1 Modulates Cilia Length in Renal Epithelial Cells

Lowe syndrome is an X-linked disorder characterized by cataracts at birth, mental retardation and progressive renal malfunction that results from loss of function of the OCRL1 (oculocerebrorenal syndrome of Lowe) protein. OCRL1 is a lipid phosphatase that converts phosphatidylinositol 4,5-bisphosphate to phosphatidylinositol 4-phosphate. The renal pathogenesis of Lowe syndrome patients has been suggested to result from alterations in membrane trafficking, but this cannot fully explain the disease progression. We found that knockdown of OCRL1 in zebrafish caused developmental defects consistent with disruption of ciliary function, including body axis curvature, pericardial edema, hydrocephaly and impaired renal clearance. In addition, cilia in the proximal tubule of the zebrafish pronephric kidney were longer in ocrl morphant embryos. We also found that knockdown of OCRL1 in polarized renal epithelial cells caused elongation of the primary cilium and disrupted formation of cysts in three-dimensional cultures. Calcium release in response to ATP was blunted in OCRL1 knockdown cells, suggesting changes in signaling that could lead to altered cell function. Our results suggest a new role for OCRL1 in renal epithelial cell function that could contribute to the pathogenesis of Lowe syndrome.     

Grafting of cucumber as a means to minimize copper toxicity

The aim of the current work was to determine whether grafting could improve copper (Cu) tolerance of cucumber, and to study the changes induced by the rootstock in the shoot growth at agronomical and physiological levels. A greenhouse experiment was carried out to determine yield, growth, fruit quality, leaf gas exchange, chlorophyll and carotenoids contents, electrolyte leakage, mineral composition and assimilate partitioning of cucumber plants (Cucumis sativus L. cv. ‘Akito’), either ungrafted or grafted onto the commercial rootstock ‘Shintoza’ (Cucurbita maxima Duchesne × Cucurbita moschata Duchesne) and cultured in nutrient film technique (NFT). Plants were supplied with nutrient solutions having three levels of Cu concentration [0.3 (control), 47, or 94 μM]. Significant depression of yield, shoot and root biomass production, and fruit quality (low fruit pH, and high Cu content) in Cu treated cucumber plants was observed, and this effect varied as a function of Cu concentration in NFT solution. The relative yield of cucumber decreased by ≈3.4% for each unit of increase in leaf tissue Cu concentrations above the threshold value (7.8 μg g⁻¹). At the two higher Cu concentrations (47 and 94 μM Cu), the percentages of yield, shoot and root biomass weight reductions were significantly lower in grafted plants in comparison to those of the ungrafted plants. Excessive Cu, especially at 94 μM Cu, inhibited photosynthesis, pigment synthesis, and membrane integrity. The Cu-related reductions in net assimilation, stomatal conductance, chlorophyll and carotenoid content were more severe in ungrafted plants in comparison with those grafted on 'Shintoza’. The percentage of electrolyte leakage was significantly higher in ungrafted plants especially those with severe Cu toxicity (94 μM Cu). The accumulation of Cu in leaf tissue at 47 and 94 μM Cu, with respect to control, were significantly lower in grafted plants (138 and 181%, respectively) in comparison to that of ungrafted plants (about 235 and 392%, respectively). Significant reduction of macro- (N, K, Ca and Mg) and micro-elements (Fe, Mn and Zn) in cucumber leaf tissue was found under moderate and severe Cu stresses especially on ungrafted plants. The improved crop performance of grafted plants was attributed to their strong capacity to inhibit Cu accumulation in the aerial parts and to maintain a better plant nutritional status.     

Evaluation of dried distillers' grains with solubles (DDGS) as a protein source for broilers

Male broiler chicks (n=120) were fed diets containing 0, 5, 10 or 15% dried distillers' grains with solubles (DDGS) from the 12th day up to the end of fattening (day 35). During this period feed intake, weight gain and excreta quality (pH, DM) were tested. A digestibility trial was carried out on four birds from each group on the last five days of the experiment to determine the digestibility of organic matter and CP of the different diets. The protein digestibility was evaluated using three different methods; uric acid correction, alpha-amino-N and amino acid-N. There were no significant effects of increased DDGS levels on feed intake, weight gain, excreta quality or digestibility of CP and organic matter. However, feed conversion showed a tendency to decline at the highest DDGS level (15%). Digestibility of DDGS protein was estimated to be 77%. There was no significant difference between uric acid and alpha-amino-N method, but both methods had a significantly lower CP digestibility than amino acid-N. The present results indicate that DDGS can be used as a protein source in diets for fattening broilers up to 10-15%.     

Cytotoxicity and acid ceramidase inhibitory activity of 2-substituted aminoethanol amides

The acid ceramidase (AC) inhibitory activity of octanoylamides, p-tert-butylbenzamides and pivaloylamides of several 2-substituted aminoethanols is reported. All the aminoethanol amides bearing a hexadecyl substituent (C16), as well as (S)-N-(1-(hexadecylthio)-3-hydroxypropan-2-yl)pivaloylamide (SC16-tb) were inhibitory in cell lysates overexpressing AC, while all other compounds were not inhibitors. Kinetic experiments with (R,E)-N-(1-hydroxyoctadec-3-en-2-yl)pivaloylamide (E-tb) and SC16-tb showed that inhibition was competitive, with K(i) values of 34 and 94.0 microM, respectively. None of the compounds inhibited neutral ceramidase. Compounds E-tb and E-c7 (the octanoylamide of the unsaturated base E), which elicited a dose-response inhibition with IC(50) values around 15 microM, were the only AC inhibitors in intact cells. Both compounds were toxic to A549 cells with LD(50) values nearly 40 microM. Flow cytometry studies with E-tb evidenced that this compound induced a concentration-dependent cell cycle arrest at G(1) and a 20-25% apoptosis/late apoptosis/necrosis after a 24-h incubation at 50 microM. In agreement with its activity as acidic ceramidase inhibitor, this effect was accompanied with an increase in the amounts of C14, C16 and C18 ceramides (LC-MS analyses), which suggested that these lipids may be responsible for the cytotoxic activity of E-tb.     

Optimization of a fermentation process for bioinsecticide production by <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis>

In an attempt to develop a cost-effective process for bioinsecticide production by B. thuringiensis, the feeding regime during aerobic cultivation of the bacterium was investigated and optimized. The process was designed as a two-stage process; a first stage of active growth, where glucose and other nutrients were adequately supplied to the growing cells over 12 h, followed by a second stage of 2 h for spore formation and toxin release. In order to maximize spore and toxin yield and productivity, different quantities of glucose and nutrients were fed separately to the growing cells in four different fermentation runs. In all runs, glucose was converted to bacterial biomass during the first stage and subsequently to spores and crystal protein during the second phase. The best results were obtained with a fermentation run supplied with 190 g glucose in 1500 ml. Up to 20.1 g of bacterial insecticides/l were recovered from fermentation broth with a glucose to toxin conversion yield of 0.159 g/g. Also, a markedly high spore concentration of 2.31 × 10¹² c.f.u./ml was obtained. The spore–crystal protein mixture obtained was tested for its insecticidal activity against three of the most agronomically important pests. Among the bioinsecticide-treated insect pests, Egyptian cotton leafworm, Spodoptera littoralis was the most susceptible pest with the lowest LC₅₀ of the bioinsecticides against its larval instar and the highest virulence against adults emerged later on from the surviving larvae.