Experimental and Theoretical Studies of α-Linolenic Acid as Green Corrosion Inhibitor for Carbon Steel in 0.5 M Sulfuric Acid.

A component of Salvia hispanica, α-linolenic acid, has been evaluated as a green corrosion inhibitor for 1018 carbon steel in 0.5 M sulfuric acid using weight loss tests, potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) measurements. Theoretical calculations using Density Functional Theory (DFT) were used also. The results have shown that this compound is a good corrosion inhibitor, with an efficiency which increased with an increase in its concentration up to 600 ppm, but it decreased with a further increase in the concentration. α-linolenic acid formed protective corrosion products layer because it was chemically adsorbed onto the steel surface according to a Langmuir type of adsorption isotherms. Polarization curves have shown that α-linolenic acid is a good, mixed type of inhibitor with a predominant effect on the cathodic hydrogen evolution reactions. EIS measurements indicated a charge transfer-controlled corrosion process. DFT calculations indicated that α-linolenic acid was more efficient in an acidic environment than in a neutral one because has a high tendency to donate electrons and can be easily protonated. In addition to this, it had the highest EHUMO value, the best chemical reactivity, the greatest tendency to transfer electrons and a greater facility of modifying its electronic configuration in the presence of carbon steel specimens according to its chemical hardness value.

Protective effects of tryptophan on neuro-inflammation in rats after administering lipopolysaccharide.

Tryptophan (TRP), which plays an important role in immune system regulation, protein synthesis, serotonin (5-HT) and melatonin production, is a potent endogenous free radical scavenger and antioxidant. The aim of this work was to determine the efficacy of TRP in neuro-inflammation induced by systemic administration of lipopolysacharide (LPS, 20mg/kg) which promotes the synthesis of free radical (LPO: MDA and 4-HDA), and pro-inflammatory cytokine Interferon-γ (IFN-γ) in different brain regions (cerebral cortex and hippocampus) of rats. Experiments were performed on adult female, pregnant and lactating rats fed with a diet of TRP content (0.5mg/100g protein), cerebral cortex and hippocampus were evaluated for lipid peroxidation (LPO) products, nitrites, nitrates and plasmatic concentration of IFN-γ. LPO levels in LPS+TRP groups were significantly decreased than that obtained in the LPS group. However, there were no observed differences in plasmatic levels of nitrites and nitrates as well as IFN-γ, neither in the cerebral cortex or hippocampus. The TRP has protective effect in the oxidative damage in a model of endotoxic shock in the breading nurslings induced by the systemic administration of LPS, acting as a scavenger of free radicals. So, it can be proposed as an innocuous protector agent in the endotoxic shock process.

Kinetoplastid genomics: the thin end of the wedge.

The completion of the genome sequencing projects for major pathogens Trypanosoma brucei, Trypanosoma cruzi and Leishmania major has enabled numerous studies that would have been difficult or impossible to perform otherwise. New technologies in sequencing and protein analyses promise further rapid expansion in our capabilities. The keys to successful use of these new tools are recognizing the power and limitations of studies performed thus far, grasping the unrealized potential of new and developing technologies, and creating access to a multidisciplinary set of skills that will facilitate research, particularly in the bioinformatic analysis of the reams of data that will be forthcoming. In this Discussion, we will provide an overview of kinetoplastid genomics studies with emphasis on studies advanced through genomic data, and a preview of what may come in the near future.

A population study of the minicircles in Trypanosoma cruzi: predicting guide RNAs in the absence of empirical RNA editing.

BACKGROUND: The structurally complex network of minicircles and maxicircles comprising the mitochondrial DNA of kinetoplastids mirrors the complexity of the RNA editing process that is required for faithful expression of encrypted maxicircle genes. Although a few of the guide RNAs that direct this editing process have been discovered on maxicircles, guide RNAs are mostly found on the minicircles. The nuclear and maxicircle genomes have been sequenced and assembled for Trypanosoma cruzi, the causative agent of Chagas disease, however the complement of 1.4-kb minicircles, carrying four guide RNA genes per molecule in this parasite, has been less thoroughly characterised. RESULTS: Fifty-four CL Brener and 53 Esmeraldo strain minicircle sequence reads were extracted from T. cruzi whole genome shotgun sequencing data. With these sequences and all published T. cruzi minicircle sequences, 108 unique guide RNAs from all known T. cruzi minicircle sequences and two guide RNAs from the CL Brener maxicircle were predicted using a local alignment algorithm and mapped onto predicted or experimentally determined sequences of edited maxicircle open reading frames. For half of the sequences no statistically significant guide RNA could be assigned. Likely positions of these unidentified gRNAs in T. cruzi minicircle sequences are estimated using a simple Hidden Markov Model. With the local alignment predictions as a standard, the HMM had an ~85% chance of correctly identifying at least 20 nucleotides of guide RNA from a given minicircle sequence. Inter-minicircle recombination was documented. Variable regions contain species-specific areas of distinct nucleotide preference. Two maxicircle guide RNA genes were found. CONCLUSION: The identification of new minicircle sequences and the further characterization of all published minicircles are presented, including the first observation of recombination between minicircles. Extrapolation suggests a level of 4% recombinants in the population, supporting a relatively high recombination rate that may serve to minimize the persistence of gRNA pseudogenes. Characteristic nucleotide preferences observed within variable regions provide potential clues regarding the transcription and maturation of T. cruzi guide RNAs. Based on these preferences, a method of predicting T. cruzi guide RNAs using only primary minicircle sequence data was created.

[Results of an outpatient major surgery program in ophthalmology]. / Resultados de un programa de cirugía mayor ambulatoria en oftalmología.

PURPOSE: To evaluate the outcomes in our hospital of an ambulatory major surgery program in patients with a variety of different ocular pathologies. METHOD: This retrospective study includes 13,878 patients who underwent programmed surgery by the Department of Ophthalmology between September 1998 and December 2004. Different ophthalmological surgical procedures were performed as outpatient surgery in 11,187 patients, with cataract surgery (phacoemulsification) being the most frequent operation performed (8,155 cases). We have analysed several indicators (substitution, suspension, admission and readmission rates), as well as surgical yield and systemic and ocular complications which appeared within 72 hours after surgery. The variables were measured as relative frequencies. The evolution of complications during the study period was analysed by the Chi-square trend test. RESULTS: 13,878 patients had ophthalmic surgery during the study period; 11,187 had outpatient surgery with a global substitution ratio of 80.6%. The median surgical yield was 74.36%. The admission rate after surgery was 4.46% (499 patients), with 92.18% (460) of these requiring immediate admission. Twenty-one patients suffered from severe complications (cardiovascular, neurological, metabolic, infectious), representing a proportional risk of 1:532. Forty-five patients had less severe complications (arterial hypertension, nausea, vomiting, vasovagal syncope) that required admission to hospital. Ophthalmologic complications occurred in 79 cases (0.56%). CONCLUSIONS: Ambulatory major surgery (AMS) is an excellent organization model of multidisciplinary surgical assistance that makes it possible to treat well selected patients in an effective, safe and efficient manner. There is a low incidence of postoperative complications of variable severity despite following the optimum requisites, although fortunately mortality is practically absent.

Influence of verapamil and diclofenac on leukocyte migration in rats.

Nonsteroidal anti-inflammatory drugs and calcium channel blockers can reduce inflammatory responses. Leukocytes play an important role in these responses. An increased expression of adhesion molecules may increase leukocyte migration. Verapamil and diclofenac are known to reduce leukocyte-endothelium interaction. To investigate a possible synergism between these drugs that could be beneficial in cardiovascular diseases, we studied leukocyte behavior by using intravital microscopy. Venules of the spermatic fascia of anesthetized Wistar rats were observed with a closed-circuit TV coupled to an optical microscope. The number of leukocytes rolling along the venular endothelium ("rollers"), sticking after application of a stimulus such as leukotriene B(4) or zymozan-activated plasma ("stickers"), or migrating after a carrageenan stimulus was reduced by verapamil at the dose of 10 mg/kg IP and by diclofenac at the dose of 2.5 mg/kg IP. The combination of both did not augment the effect of each agent alone. Verapamil, diclofenac, or their combination did not interfere with vessel diameter, number of circulating leukocytes, blood pressure levels, or heart rate. Verapamil alone or together with diclofenac reduced venular blood flow velocity and in consequence, the venular shear rate. Our data allow us to suggest that these drugs might interfere with the expression of adhesion cell molecules to reduce cell migration in inflammation. The lack of synergism between the drugs might be explained by the reduction in venular shear rate induced by verapamil, which might not be sufficient to hinder the effect of verapamil alone but hindered the summation effects of both.