Igor Viana Brandi

Toxicidade aguda dos extratos hidroalcoólicos das folhas de alecrim-pimenta, aroeira e barbatimão e do farelo da casca de pequi administrados por via intraperitoneal

This study aimed to conductpre-clinical toxicology testing to investigate the toxicity of Lippia sidoides Cham., Myracrodruon urundeuva Fr. All., Stryphnodendron adstringens (Mart.) Coville and Caryocar brasiliense Camb., by determining the 50% (LDL50) lethal dose. In the investigation of the LD50, groups of Swiss mice of the same sex were used (n=150; 30 animals per plant and all inoculated intraperitoneally with serial dilutions of the aqueous fraction obtained from the leaves of plants. After inoculation, the animals were observed along a period of 14 days in order to observe the dead, sick and survivors rate. In mice inoculated intraperitoneally, the acute pre-clinical toxicology testing demonstrated toxicity equal to 0,31mg mL-1 LD50 mL-1 for all plants. The exception was for Stryphnodendron adstringens, which presented toxicity equal to a 0,25mg mL-1DL50 mL-1 and values expressed in terms of dilution. Research should be conducted to obtain data on toxicity of the plants in other ways to ensure the use in human and animal health. Therefore, the studied plants should be used with caution. They present a relatively mild toxic potential, but it may be harmful to users if they are not properly utilized.

Modified toxin-binding inhibition (ToBI) test for epsilon antitoxin determination in serum of immunized rabbits

The aim of the present study was to evaluate and standardize the ToBI test in vitro as a substitute for the serum neutralization test in mice for quality control of clostridial vaccines. The ToBI test in vitro was used to evaluate 40 serum samples of known antibody content, obtained from rabbits immunized against clostridiosis with experimental vaccine. The correlation between epsilon antitoxin titers in rabbit sera, determined by the ToBI test and serum neutralization in mice, ranged from 0.222% to 0.452% in polyvalent vaccines and from 0.154% to 0.387% in monovalent vaccines. Interplate coefficients of variation were not significant, reaching 0.350% in polyvalent vaccines and 0.400% in monovalent vaccines, indicating high homogeneity. In conclusion, the ToBI test in vitro is suitable for assessing the potency of clostridial vaccines and may be used as an alternative method able to replace current in vivo tests.

Anti-botulism single-shot vaccine using chitosan for protein encapsulation by simple coacervation.

The aim of the present study was to compare the potency and safety of vaccines against Clostridium botulinum (C. botulinum) type C and D formulated with chitosan as controlled release matrix and vaccines formulated in conventional manner using aluminum hydroxide. Parameters were established for the development of chitosan microspheres, using simple coacervation to standardize the use of this polymer in protein encapsulation for vaccine formulation. To formulate a single shot vaccine inactivated antigens of C.xa0botulinum type C and D were used with original toxin titles equal to 5.2 and 6.2 log LD50/ml, respectively. For each antigen a chitosan based solution of 50xa0mL was prepared. Control vaccines were formulated by mixing toxoid type C and D with aluminum hydroxide [25% Al(OH)3, pH 6.3]. The toxoid sterility, innocuity and potency of vaccines were evaluated as stipulated by MAPA-BRASIL according to ministerial directive no. 23. Encapsulation efficiency of BSA in chitosan was 32.5-40.37%, while that the encapsulation efficiency to toxoid type C was 41,03% (1.94xa0mg/mL) and of the toxoid type D was 32.30% (1.82xa0mg/mL). The single shot vaccine formulated using chitosan for protein encapsulation through simple coacervation showed potency and safety similar to conventional vaccine currently used in Brazilian livestock (10 and 2 IU/mL against C.xa0botulinum type C and D, respectively). The present work suggests that our single shot vaccine would be a good option as a cattle vaccine against these C.xa0botulinum type C and D.

Growth conditions of clostridium perfringens type B for production of toxins used to obtain veterinary vaccines.

The diseases caused for Clostridiumperfringens are generically called enterotoxemias because toxins produced in the intestine may be absorbed into the general circulation. C. perfringens type B, grown in batch fermentation, produced toxins used to obtain veterinary vaccines. Glucose in concentrations of 1.4–111.1xa0mM was used to define the culture medium. The minimum concentration for a satisfactory production of vaccines against clostridial diseases was 55.6xa0mM. Best results were brought forth by meat and casein peptones, both in the concentration 5.0xa0gxa0l−1 in combination with glucose and a culture pH maintained at 6.5 throughout the fermentation process. The production of lactic, acetic and propionic organic acids was observed. Ethanol was the metabolite produced in the highest concentration when cultures maintained steady pH of 6.5 with exception of cultures with initial glucose concentration of 1.4xa0mM, where the highest production was of propionic acid. Maximal cell concentration and the highest toxin title concomitantly low yield coefficient to organic acids and ethanol were obtained using basal medium containing 111.1xa0mM glucose under a controlled pH culture (pH) 6.5 in batch fermentations of C. perfringens type B. These data contribute to improve process for industrial toxin production allowing better condition to produce a toxoid vaccine.

Synthesis of supermacroporous cryogel for bioreactors continuous starch hydrolysis

A bioreactor was built by means of immobilizing alpha‐amylase from Aspergillus oryzae by encapsulation, through cryopolymerization of acrylamide monomers for the continuous starch hydrolysis. The starch hydrolysis was evaluated regarding pH, the concentration of immobilized amylase on cryogel, the concentration of starch solution and temperature. The maximum value for starch hydrolysis was achieved at pH 5.0, concentration of immobilized enzyme 111.44 mg amylase/gcryogel, concentration of starch solution 45 g/L and temperature of 35°C. The immobilized enzyme showed a conversion ratio ranging from 68.2 to 97.37%, depending on the pH and temperature employed. Thus, our results suggest that the alpha‐amylase from A. oryzae immobilized on cryogel monoliths represents a potential process for industrial production of maltose from starch hydrolysis.

The role of the angiotensin II type I receptor blocker telmisartan in the treatment of non-alcoholic fatty liver disease: a brief review

Non-alcoholic fatty liver disease (NAFLD) is currently considered an important component of metabolic syndrome (MetS). The spectrum of NAFLD includes conditions that range from simple hepatic steatosis to non-alcoholic steatohepatitis. NAFLD is correlated with liver-related death and is predicted to be the most frequent indication for liver transplantation by 2030. Insulin resistance is directly correlated to the central mechanisms of hepatic steatosis in NAFLD patients, which is strongly correlated to the imbalance of the renin–angiotensin system, that is involved in lipid and glucose metabolism. Among the emerging treatment approaches for NAFLD is the anti-hypertensive agent telmisartan, which has positive effects on liver, lipid, and glucose metabolism, especially through its action on the renin–angiotensin system, by blocking the ACE/AngII/AT1 axis and increasing ACE2/Ang(1–7)/Mas axis activation. However, treatment with this drug is only recommended for patients with an established indication for anti-hypertensive therapy. Thus, there is an increased need for large randomized controlled trials with the aim of elucidating the effects of telmisartan on liver disease, especially NAFLD. From this perspective, the present review aims to provide a brief examination of the pathogenesis of NAFLD/NASH and the role of telmisartan on preventing liver disorders and thus to improve the discussion on potential therapies.

ELISA and modified toxin-binding inhibition test for quality control of the clostridial vaccine processes

This study aimed to assess and standardize the ELISA and modified ToBI test in vitro methods in order to verify the potency of epsilon toxicoid in comparison with the in vivo TCP method. The following epsilon toxoids were used: NIBSC standard from batches 375/07, 532/08, 551/08, 373/07 and 378/07. These were evaluated using a TCP test, ELISA and ToBI tests. The results indicate that the correlation ratio between the dilutions of standard NIBSC toxicoid and absorbance values of 89.44% obtained with the ELISA method support the use of the curve to evaluate epsilon toxoids. However, it was observed that the absorbance values were similar for all toxoids, thus presenting no significant difference between higher and lower concentration toxoids. For the ToBI test, the correlation ratio of 96.76, obtained in the curve pattern, demonstrates the effectiveness of the curve to be used in the epsilon toxoid evaluation. The correlation ratio between the titration degrees of toxoids obtained through TCP and ToBI tests was higher than 90%. It is concluded that the type of ELISA test used does present discriminative power for toxoids with different concentrations, which does not support the use of this technique for such a purpose. The ToBI test can be used as a screening method for it is sensitive and effective to detect epsilon toxicoid produced by C. perfringens type D.

The usefulness of short-term high-fat/high salt diet as a model of metabolic syndrome in mice

ABSTRACT Diabetic cardiomyopathy (DC) describes diabetes‐associated changes in the structure and function of myocardium that are not directly linked to other factors such as hypertension. Currently there are some models of DC; however, they take a large time period to mimic key features. In the present study, we investigated the effects of a short‐term high‐fat/high salt diet (HFHS) treatment on myocardial function and structure, and vascular reactivity in C57BL/6 male mice. After 14 weeks HFHS induced hypertension (MAP = 144.95 ± 16.13 vs 92.90 ± 18.95 mm Hg), low glucose tolerance (AUC = 1049.01 ± 74.79 vs 710.50 ± 52.57 a.u.), decreased insulin sensitivity (AUC = 429.83 ± 35.22 vs 313.67 ± 19.55 a.u.) and increased adiposity (epididymal fat weight 0.96 ± 0.10 vs 0.59 ± 0.06 OW/BW × 102), aspects present in metabolic syndrome. Cardiac evaluation showed diastolic dysfunction (E/A ratio = 1.20 vs 1.90 u.a.) and cardiomyocyte hypertrophy (cardiomyocyte area = 502.82 ± 31.46 vs 385.58 ± 22.11 &mgr;m2). Lastly, vascular reactivity was impaired with higher contractile response (136.10 ± 3.49 vs 120.37 ± 5.43%) and lower response to endothelium‐dependent vasorelaxation (74.01 ± 4.35 vs 104.84 ± 3.57%). In addition, the diet was able to induce an inward coronary remodeling (vascular total area: SCNS 6185 ± 800.6 vs HFHS 4085 ± 213.7 &mgr;m2). Therefore, we conclude that HFHS short‐term treatment was able to induce metabolic syndrome‐like state, cardiomyopathy and vascular injury working as an important tool to study cardiometabolic diseases.

Characterization of the Catalytic Structure of Plant Phytase, Protein Tyrosine Phosphatase-Like Phytase, and Histidine Acid Phytases and Their Biotechnological Applications

Phytase plays a prominent role in monogastric animal nutrition due to its ability to improve phytic acid digestion in the gastrointestinal tract, releasing phosphorus and other micronutrients that are important for animal development. Moreover, phytase decreases the amounts of phytic acid and phosphate excreted in feces. Bioinformatics approaches can contribute to the understanding of the catalytic structure of phytase. Analysis of the catalytic structure can reveal enzymatic stability and the polarization and hydrophobicity of amino acids. One important aspect of this type of analysis is the estimation of the number of β-sheets and α-helices in the enzymatic structure. Fermentative processes or genetic engineering methods are employed for phytase production in transgenic plants or microorganisms. To this end, phytase genes are inserted in transgenic crops to improve the bioavailability of phosphorus. This promising technology aims to improve agricultural efficiency and productivity. Thus, the aim of this review is to present the characterization of the catalytic structure of plant and microbial phytases, phytase genes used in transgenic plants and microorganisms, and their biotechnological applications in animal nutrition, which do not impact negatively on environmental degradation.

Total combining power: Technique for the evaluation of the quality control process of clostridiosis vaccines.

An efficient technique for evaluation of the quality control of vaccines against clostridiosis is described in this study. This technique is capable of quantifying the toxoid of the bacterium Clostridium perfringens Type D, which is commonly found within these vaccines. The described method is performed in vivo to quantify the toxoid, replacing the current predominant approaches that use the titration of toxins before the inactivation process. This method is based on the partial neutralization of a determined dose of antitoxin by testing different doses of the toxoid. In order to guarantee its reliability, it is essential for the technique to be validated. Thus, the technique was tested using the following validation parameters: specificity and selectivity, detection limit, linear correlation, precision and robustness, in agreement with the requirements of regulatory agencies and international committees from around the world. The method was found to be specific, selective, robust, precise, and linear inside a specific concentration range. Therefore, it could be applied to the quality control of clostridiosis vaccines with satisfactory results.