Sites of action of adenosine in interorgan preconditioning of the heart

The mechanism underlying interorgan preconditioning of the heart remains elusive, although a role for adenosine and activation of a neurogenic pathway has been postulated. We tested in rats the hypothesis that adenosine released by the remote ischemic organ stimulates local afferent nerves, which leads to activation of myocardial adenosine receptors. Preconditioning with a 15-min mesenteric artery occlusion (MAO15) reduced infarct size produced by a 60-min coronary artery occlusion (60-min CAO) from 68 +/- 2% to 48 +/- 4% (P < 0.05). Pretreatment with the ganglion blocker hexamethonium or 8-(p-sulfophenyl)theophylline (8-SPT) abolished the protection by MAO15. Intramesenteric artery (but not intraportal vein) infusion of adenosine (10 microg/min) was as cardioprotective as MAO15, which was also abolished by hexamethonium. Whereas administration of hexamethonium at 5 min of reperfusion following MAO15 had no effect, 8-SPT at 5 min of reperfusion abolished the protection. Permanent reocclusion of the mesenteric artery before the 60-min CAO enhanced the cardioprotection by MAO15 (30 +/- 5%), but all protection was abolished when 8-SPT was administered after reocclusion of the mesenteric artery. Together, these findings demonstrate the involvement of myocardial adenosine receptors. We therefore conclude that locally released adenosine during small intestinal ischemia stimulates afferent nerves in the mesenteric bed during early reperfusion, initiating a neurogenic pathway that leads to activation of myocardial adenosine receptors.     

Effect of Cadmium Stress on the Growth,Physiology, Stress Markers,Antioxidants and Stomatal Behaviour of Two Genotypes of Chickpea ( <i>Cicer arietinum </i>L.)

The current work was performed to know the impact of cadmium (Cd) toxicity on two different genotypes of chickpea (Cicer arietinum L.) namely Pusa-BG1053 and Pusa-BG372. Cadmium was applied in the form of cadmium chloride (CdCl₂), in varying levels, 0, 25, 50, 75, and 100 mg Cd kg^-1 soil. Plant growth as well as physiological attributes were decreased with increasing concentration of Cd. Both genotypes showed the maximum and significant reduction at the maximum dose of Cd (100 mg Cd kg^-1 soil). Results of this study proved that the genotype Pusa-BG1053 was more tolerant and showed a lower decline in growth, photosynthetic and biochemical attributes than Pusa-BG372. This later genotype showed the maximum reduction and was sensitive to Cd stress. A better activity of antioxidants protected Pusa-BG1053 from Cd toxicity; on the other hand, the activity of antioxidants was much lower in Pusa-BG372. Scanning electron microscopic studies showed differences in both genotypes. In Pusa-BG1053, stomatal quantity was higher and stomata were slightly close to the characteristic guard cells. In Pusa-BG372 stomata were lower, slightly open and with highly affected guard cells. Root cell mortality due to the harsh effects of Cd appeared to be more evident in Pusa-BG372 than Pusa-BG1053, which was visible under a confocal microscope. As a result of this study, Pusa-BG1053 was a more tolerant genotype, and exhibited a minimum reduction in terms of all studied parameters than Pusa-BG372, which was a sensitive genotype to Cd toxicity.

     

An overview on transesterification of natural oils and fats

Transesterification of natural oils and fats has found various industrial applications, particularly in producing surfactants and biodiesel fuel. Due to the biodegradability and environmental compatibility of the products, many studies have been conducted in this area. An overview on transesterification of natural oils and fats is presented which includes the following topics: Catalytic and non-catalytic reactions and their optimum reaction conditions; types of catalysts and alcoholysis; reaction kinetics and mass transfer. The reports and findings from these aspects collectively provide useful information and serve as good guidelines for transesterification research.     

A crucial role for tumor necrosis factor receptor 1 in synovial lining cells and the reticuloendothelial system in mediating experimental arthritis

Introduction  

Rheumatoid arthritis (RA) is an autoimmune inflammatory disease that mainly affects synovial joints. Biologics directed against tumor-necrosis-factor (TNF)-α are efficacious in the treatment of RA. However, the role of TNF receptor-1 (TNFR1) in mediating the TNFα effects in RA has not been elucidated and conflicting data exist in experimental arthritis models. The objective is to investigate the role of TNFR1 in the synovial lining cells (SLC) and the reticuloendothelial system (RES) during experimental arthritis.     

Role of surfactant and pH on dissolution properties of fenofibrate and glipizide—A technical note

Depending on the dose size and solubility characteristics of low solubility drugs, a meaningful and discriminatory power of dissolution rate testing can be demonstrated. Saturation solubility of fenofibrate and glipizide in different media were determined. Solubility of fenofibrate increased directly with SLS concentration. For a 54-mg fenofibrate tablet, SLS at 0.025 M level is required for a discriminative dissolution test, while for 160-mg tablet, dissolution condition and levels of SLS should be optimized; higher concentrations may be effective (ie, 0.052 M, ∼1.5%). A pH 6.8 phosphate buffer medium is appropriate for glipizide 10-mg tablet dissolution study, when formulation ingredients include excipients with surface activity (eg, HPMC).     

A rapid high performance liquid chromatographic determination of methyldopa in human serum with fluorescence detection and alumina extraction: application to a bioequivalence study

A simple and ultra rapid high performance liquid chromatographic (HPLC) method coupled with alumina extraction and fluorescence detection was described for determination of methyldopa in human serum. The drug and an internal standard were adsorbed onto alumina and eluted using acidic methanol. The eluate was directly injected onto ODS reverse phase column using a mixture of phosphate buffer (0.05 M) containing triethylamine (100 microl/l, v/v; pH 2.3) and methanol (92:8, v/v) at a flow rate of 2.1 ml/min as the mobile phase. The fluorescence detector excitation and emission wavelengths were set at 270 and 320 nm, respectively. No interference in the assay from any endogenous substances or other concurrently used drugs was observed and the retention times of I.S. and the drug were 1.7 and 2.4 min, respectively with total run time (injection to injection) of less than 3.5 min. The limit of quantification was evaluated to be 2 ng/ml. Validity of the method was studied and the method was precise and accurate with a linearity range from 20 ng/ml to 5000 ng/ml. This method has been used in a randomized crossover bioequivalence study of two different methyldopa preparations in 24 healthy volunteers.     

Evaluation of antibody levels during simultaneous aflatoxicosis and vaccination against infectious laryngotracheitis in pullets

Chickens fed 200ppb aflatoxin from 10 days of age were evaluated for their immune response to a modified live infectious laryngotracheitis vaccine. Vaccination was administered at age 4 and 12 weeks. Antibody titers to the vaccine were reduced in chickens given dietary aflatoxin. After 7 weeks, aflatoxin feeding was continued for one month in a treated group and was withdrawn in another. Serology indicated significant differences between the two treated groups relative to whether aflatoxin was fed or not. Significant reduction in body weights, antibody titers and elevated SGOT and SGPT levels were found in chickens treated with aflatoxin. The impact of aflatoxin on reduced body weight, decreased SGOT and SGPT levels and lower antibody titers was shown to be significant in the treated group fed on a ration of aflatoxin until throughout the experiment.