Hemolytic activity of alternative complement pathway as an indicator of innate immunity in pacu (Piaractus mesopotamicus)

The objective of this study was to evaluate the methodology to establish the hemolytic activity of alternative complement pathway as an indicator of the innate immunity in Brazilian fish pacu (Piaractus mesopotamicus), in addition to verifying the influence of β-glucan as an immunostimulant. Fish were fed with diets containing 0, 0.1 and 1% β-glucan, during seven days, and then inoculated with Aeromonas hydrophila. Seven days after the challenge, they were bled for serum extraction. The methodology consisted of a kinetic assay that allows calculating the required time for serum proteins of the complement to promote 50% lysis of a rabbit red blood cell suspension. The method developed in mammals was successfully applied for pacu and determined that the hemolytic activity of the proteins of the complement system (alternative pathway) increased after the pathogen challenge, but was not influenced by the β-glucan treatment.

Correlation among Antioxidant, Antimicrobial, Hemolytic, and Antiproliferative Properties of Leiothrix spiralis Leaves Extract

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Correlations between differences in amino-terminal sequences and different hemolytic activity of sticholysins

Sticholysins I and II (St I and St II) are cytolysins produced by the sea anemone Stichodactyla helianthus. In spite of their 93% sequence homology, St II is more hemolytic against human erythrocytes than St 1. In order to establish the possible causes of this difference, we studied the hemolytic activity of synthetic peptides containing sequences from the N-termini of both proteins. The results demonstrated that the differences in hemolytic activity of the toxins could be ascribed at least partly to differences in their N-termini. (c) 2007 Elsevier Ltd. All rights reserved.

The hemolytic uremic syndrome as a complication of adriamycin nephropathy

Rats treated with two injections of adriamycin (week 0 and week 12) developed glomerusclerosis and severe tubulointerstitial lesions as described in the literature. In addition, a number of glomerular alterations were present. These included capillary loop dilation, insudation of eosinophilic material, necrosis, duplication of the glomerular basement membrane, severe mesangiolysis with disruption of the mesangial matrix and segmental double- contours. The renal arterioles and interlobular arteries showed endothelial cell swelling. The subendothelial space was infiltrated by fibrinoid material and there was intensive fibrinoid necrosis of the wall of both arteries and arterioles extending into the glomerular tuft. These alterations were very similar to those observed in the hemolytic uremic syndrome. This observation suggests that the two injections of adriamycin, with a long interval in between them, might induce renal lesions similar to those observed in the hemolytic uremic syndrome.

Influence of antimicrobial subinhibitory concentrations on hemolytic activity and bacteriocin-like substances in oral: Fusobacterium nucleatum

Fusobacterium nucleatum is considered for its role in colonization of initial and late microorganisms in dental plaque and for its coaggregation with other bacterial species. It is known that action of different antimicrobial substances may interfere with either virulence factors or with host-bacteria interaction. The goal of this study was to examine the influence of subinhibitory concentrations of chlorhexidine, triclosan , penicillin G and metronidazole on hemolytic activity and bacteriocin-like substance production of oral F. nucleatum. A high resistance to penicillin G was observed and 63% of the isolates were β-lactamase positive. All the tested isolates were susceptible to metronidazole. F. nucleatum isolates grown with or without antimicrobials were alpha-hemolytics. Bacteriocin-like substance production was increased in isolates grown with penicillin G. Impaired production of hemolytic or antagonic substances can suggest a role in the regulation of oral microbiota.

Comparison of the hemolytic activity between C. albicans and non-albicans Candida species

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Development and pharmacological evaluation of ropivacaine-2-hydroxypropyl-beta-cyclodextrin inclusion complex

Ropivacaine (RVC) is an enantiomerically pure local anesthetic (LA) largely used in surgical procedures, which presents physico-chemical and therapeutic properties similar to those of bupivacaine (BPV), but associated to less systemic toxicity This study focuses on the development and pharmacological evaluation of a RVC in 2-hydroxypropyl-beta-cyclodextrin (HP-P-CD) inclusion complex. Phase-solubility diagrams allowed the determination of the association constant between RVC and HP-beta-CD (9.46 M-1) and showed an increase on RVC solubility upon complexation. Release kinetics revealed a decrease on RVC release rate and reduced hemolytic effects after complexation. (onset at 3.7 mM and 11.2 mM for RVC and RVCHP-beta-CD, respectively) were observed. Differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and X-ray analysis (X-ray) showed the formation and the morphology of the complex. Nuclear magnetic resonance (NMR) and job-plot experiments afforded data regarding inclusion complex stoichiometry (1:1) and topology. Sciatic nerve blockade studies showed that RVCHP-beta-CD was able to reduce the latency without increasing the duration of motor blockade, but prolonging the duration and intensity of the sensory blockade (p < 0.001) induced by the LA in mice. These results identify the RVCHP-beta-CD complex as an effective novel approach to enhance the pharmacological effects of RVC, presenting it as a promising new anesthetic formulation. (c) 2007 Elsevier B.V All rights reserved.

Isolamento e resistência a antimicrobianos de cepas de Streptococcus spp. provenientes de rãs-touro (Lithobates catesbeianus)

Twelve bullfrogs were selected from two commercial frog farms and clinically diagnosed as attacked by Streptococcus disease. Sixty samples were collected, and Streptococcus spp. was isolated from all bullfrog, being 12 (100%) from the encephalus, seven from the kidneys (58.3%), three from the liver (25%), two from the spleen (16.6%), and one from the ascitic liquid (8.3%). Streptococcus -hemolytic were isolated from all the 60 samples, which were sensible to chloramphenicol (100%), gentamycin (100%), vancomycin (96%), cefotaxime (96%), and cefoxitine (92%).

Preliminary cryocrystallography analysis of an eumenine mastoparan toxin isolated from the venom of the wasp Anterhynchium flavomarginatum micado

Mastoparans are tetradecapeptides found to be the major component of vespid venoms. These peptides present a wide spectrum of biological activities, such as mast cell degranulation, hemolytic activity and also reveals antimicrobial activity. A mastoparan toxin isolated from the venom of Anterhynchium flavomarginatum micado has been crystallized. At room temperature these crystals diffracted to 2.8 Angstrom resolution. However, upon cooling to cryogenic temperature around 85 K, the original resolution limit could be improved to 2.0 Angstrom. Crystals were determined to belong to the space group P3(1) (P3(2)). This is the first mastoparan to be crystallized and it will provide further insights in the conformational significance of mastoparan toxins, with respect to their potency and activity in G protein regulation. (C) 3001 Elsevier B.V. B.V. All rights reserved.

Identification of a novel melittin isoform from Africanized Apis mellifera venom

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Genetic differentiation between sympatric populations of Bacillus cereus and Bacillus thuringiensis

Little is known about genetic exchanges in natural populations of bacteria of the spore-forming Bacillus cereus group, because no population genetics studies have been performed with local sympatric populations. We isolated strains of Bacillus thuringiensis and B. cereus from small samples of soil collected at the same time from two separate geographical sites, one within the forest and the other at the edge of the forest. A total of 100 B. cercus and 98 B. thuringiensis strains were isolated and characterized by electrophoresis to determine allelic composition at nine enzymatic loci. We observed genetic differentiation between populations of B. cereus and B. thuringiensis. Populations of a given Bacillus species-B. thuringiensis or B. cereus-were genetically more similar to each other than to populations of the other Bacillus species. Hemolytic activity provided further evidence of this genetic divergence, which remained evident even if putative clones were removed from the data set. Our results suggest that the rate of gene flow was higher between strains of the same species, but that exchanges between B. cereus and B. thuringiensis were nonetheless possible. Linkage disequilibrium analysis revealed sufficient recombination for B. cereus populations to be considered panmictic units. In B. thuringiensis, the balance between clonal proliferation and recombination seemed to depend on location. Overall, our data indicate that it is not important for risk assessment purposes to determine whether B. cereus and B. thuringiensis belong to a single or two species. Assessment of the biosafety of pest control based on B. thuringiensis requires evaluation of the extent of genetic exchange between strains in realistic natural conditions.

Prevalence of DEA 1 canine blood group system in dogs (Canis familiaris, Linnaeus, 1758) reared in Brazil

Os cães possuem cinco grupos sangüíneos bem estabelecidos, compostos por sete determinantes antigênicos eritrocitários, os quais são denominados de dog erythrocyte antigen (DEA). O grupo DEA 1 (subgrupos 1.1, 1.2 e 1.3) tem sido considerado o mais importante no que se refere às transfusões de sangue. Isto ocorre porque esse grupo possui um alto potencial para estimulação antigênica e, dessa forma, pode estimular a produção de anticorpos se um receptor DEA 1 negativo receber uma transfusão de sangue DEA 1 positivo, levando a uma reação transfusional hemolítica em uma segunda transfusão com hemácias do tipo DEA 1. A freqüência de aparecimento do grupo DEA 1 é bem conhecida em outros países, porém, até então, não havia informações disponíveis sobre o referido grupo no Brasil. No presente estudo, objetivou-se avaliar a prevalência do grupo sangüíneo DEA 1 (subgrupos 1.1 e 1.2) em cães criados no Brasil. Para tanto, 150 cães de raças, sexos e idades diferentes, triados junto ao Hospital Veterinário da FCAV/UNESP, Campus de Jaboticabal, foram submetidos a tipagem sangüínea para o grupo DEA 1 (subgrupos 1.1 e 1.2) canino, utilizando-se reagentes adquiridos comercialmente junto ao Laboratório de Imunoematologia e Sorologia da Universidade de Michigan (EUA). Os resultados obtidos neste ensaio revelaram que a prevalência geral para o grupo DEA 1 é de 91,3%, consideradas as condições e características da população estudada, compreendendo 51,3% de cães do tipo DEA 1.1, 40% de cães do tipo DEA 1.2, e os 8,7% restantes sendo negativos para o referido grupo. A partir das prevalências encontradas, calculou-se que a probabilidade de um cão DEA 1 negativo receber sangue DEA 1.1, em uma primeira transfusão feita ao acaso, é de aproximadamente 4,5%. Sendo assim, este índice reflete um risco potencial para a sensibilização de um receptor DEA 1 negativo, o que deflagraria a produção de anticorpos. Posteriormente, se este mesmo paciente recebesse uma segunda transfusão de sangue, feita ao acaso, a probabilidade de receber hemácias do tipo DEA 1.1 seria de aproximadamente 2,3%, o que representaria o risco potencial de ocorrência de uma reação transfusional hemolítica aguda. Por outro lado, a probabilidade de este cão receber sangue do tipo DEA 1.2 seria cerca de 1,8%, o que levaria a uma reação transfusional menos grave, porém potencialmente prejudicial. No presente estudo, observou-se que o risco potencial para uma reação transfusional é mínimo, quando se trata de um cão mestiço.

Trends in rheumatic fever: clinical aspects and perspectives in prophylactic treatments

Introduction: Rheumatic fever (RF), a systemic illness that may occur following Group A beta-hemolytic streptococcal (GABHS) pharyngitis in children, is a major problem in countries with limited resources. Because of its long track record and low cost, an injection of benzathine penicillin G (BPG) suspension every 3 or 4 weeks has been used as secondary prophylaxis. Despite its excellent in vitro efficacy, the inability of BPG to eradicate GABHS has been frequently reported.Areas covered: This work reviews the possible causes of failure, as well as the inconvenience of the current prophylactic treatment of acute RF and suggests a new pharmacotherapeutic system that could replace the current one.Expert opinion: RF is a major problem concerning only countries with limited resources and could be considered as a neglected disease. The dose regimen using BPG suspension results in failures, which could be avoided by the use of nanocarrier-based systems. To meet this ultimate goal, the research should be transposed from the laboratory scale to an industrial and clinical application level. This research should be conducted to produce a pharmaceutical dosage form that will be commercially available, consumed by and affordable for patients. However, health, environmental and socioeconomic hazards should be considered.