Vasoconstrictor effect of Africanized honeybee (Apis mellifera L.) venom on rat aorta

Background: Apis mellifera stings are a problem for public health worldwide, particularly in Latin America due to the aggressiveness of its Africanized honeybees. Massive poisoning by A. mellifera venom (AmV) affects mainly the cardiovascular system, and several works have described its actions on heart muscle. Nevertheless, no work on the pharmacological action mechanisms of the AmV in isolated aorta has been reported. Thus, the present work aimed to investigate the actions of AmV and its main fractions, phospholipase A(2) (PLA(2)) and melittin, on isolated aorta rings and a probable action mechanism.Results: AmV and the complex PLA(2) + melittin (0.1-50 mu g/mL) caused contraction in endothelium-containing aorta rings, but neither isolated PLA(2) nor melittin were able to reproduce the effect. Endothelium removal did not change the maximum vasoconstrictor effect elicited by AmV. CA(2+)-free medium, as well as treatment with phentolamine (5 mu M), verapamil (10 mu M), losartan (100 mu M), and U-73122 (10 mu M, a phospholipase C inhibitor), eliminated the AmV-induced contractile effects.Conclusions: In conclusion, AmV caused contractile effect in aorta rings probably through the involvement of voltage-operated calcium channels, AT1 and alpha-adrenergic receptors via the downstream activation of phospholipase C. The protein complex, PLA(2) + melittin, was also able to induce vasoconstriction, whereas the isolated proteins were not

Evaluation of gastroprotective and ulcer healing activities of yellow mombin juice from Spondias mombin L.

Spondias mombin L. (yellow mombin) is a tree with a nutritional fruit that is commonly consumed in the North and Northeast of Brazil, as the juice of its pulp is rich in antioxidant compounds. This study aimed to investigate the gastroprotective and ulcer healing activities of yellow mombin juice (YMJ) in Wistar rats, and to elucidate the possible involved mechanisms. Phytochemical characterization of the lyophilized fruit juice was performed by high-performance liquid chromatography (HPLC). The gastroprotective activity of YMJ was investigated in ethanol (25, 50, and 100% YMJ) and indomethacin (100% YMJ) models of acute gastric ulcer in rats. Then, the effect of YMJ on mucus production and gastric secretions, and the involvement of non-protein sulfhydryl groups and prostaglandins in the gastroprotective process were examined. Moreover, the ulcer healing effect of YMJ was investigated in a model of acetic acid-induced chronic ulcer through histological and immunohistochemical analyses. HPLC results identified the presence of epicatechin (7.1 ± 1.6 μg/mL) and quercetin (17.3 ± 2.5 μg/mL) in YMJ. Ethanol-induced gastric lesions were inhibited by YMJ (25, 50, and 100%) by 42.42, 45.09, and 98.21% respectively, and indomethacin-induced lesions were inhibited by YMJ (100%) by 58.96%, compared to control group. Moreover, YMJ reduced gastric content and total acidy by 57.35 and 71.97%, respectively, compared to the control group. Treatment with YMJ also promoted healing of chronic ulcer, regeneration of the gastric mucosa, and restoration of mucus levels in glandular cells, as confirmed by histological analysis. It also increased cellular proliferation, as demonstrated by high reactivity to Ki-67 and bromodeoxyuridine. In conclusion, YMJ was found to possess gastroprotective and ulcer healing activities that are correlated to its antisecretory action. These results support the commercial exploration of YMJ as a functional food

Variables associated with the post-treatment healing of lesions in patients with American cutaneous leishmaniasis in Paraná State, Brazil

The purpose of this study was to investigate the relationship of several variables to the healing of lesions in patients with American cutaneous leishmaniasis (ACL). The patients with clinical and/or laboratorial diagnoses of the disease were followed up for varying periods after treatment by clinical evaluation and indirect immunofluorescence assay (IFA), from September 2000 to December 2003. The lesions of 85.3% of the 163 patients had healed by their last return for clinical evaluation, and of these, 82.7% had negative IFA results, indicating an association between the healing of lesions and IFA negativity (p=0.000). In patients evaluated up to 120 days after treatment, there was a significant association between negative IFA results and the healing of lesions (p=0.0000). Logistic regression analysis showed that negative IFA results on patients' first return after treatment predicted a 2.175 fold greater chance of lesion healing (p=0.0001). These results indicate an association between IFA negativity at the first return up to a period of 120 days, and the healing of lesions, and that the chances of healing are significantly higher in patients with negative IFA results at their first return after treatment.<br>O objetivo deste estudo foi investigar a associação de algumas variáveis para a cicatrização de lesões em pacientes com leishmaniose tegumentar americana (LTA). Os pacientes com diagnóstico clínico e laboratorial foram acompanhados depois do tratamento por avaliação clínica e reação de imunofluorescência indireta (IFI), de setembro de 2000 a dezembro de 2003. Dos 163 pacientes 85,3% apresentaram cicatrização das lesões no último retorno para a avaliação clínica e 82,7% destes tiveram a IFI negativa indicando uma associação entre a cicatrização das lesões e a negativação da IFI (p=0,000). Nos pacientes acompanhados até 120 dias depois do tratamento houve associação significativa entre os resultados negativos da IFI e a cicatrização das lesões (p=0,0000). A análise pela regressão logística mostrou que quando a IFI do primeiro retorno após o tratamento foi negativa, o paciente tinha 2,175 mais chance de cicatrização (p=0,0001). Os resultados mostram associação entre a negativação da IFI e a cicatrização das lesões quando o primeiro retorno foi até 120 dias e que as chances de cicatrização são significativamente maiores nos pacientes que apresentaram IFI negativa no primeiro retorno depois do tratamento

Prevalence of enterotoxin-encoding genes and antimicrobial resistance in coagulase-negative and coagulase-positive Staphylococcus isolates from black pudding

INTRODUCTION: Staphylococcal species are pathogens that are responsible for outbreaks of foodborne diseases. The aim of this study was to investigate the prevalence of enterotoxin-genes and the antimicrobial resistance profile in staphylococcus coagulase-negative (CoNS) and coagulasepositive (CoPS) isolates from black pudding in southern Brazil. METHODS: Two hundred typical and atypical colonies from Baird-Parker agar were inoculated on mannitol salt agar. Eighty-two mannitol-positive staphylococci were submitted to conventional biochemical tests and antimicrobial susceptibility profiling. The presence of coagulase (coa) and enterotoxin (se) genes was investigated by polymerase chain reaction. RESULTS: The isolates were divided into 2 groups: 75.6% (62/82) were CoNS and 24.4% (20/82) were CoPS. The biochemical tests identified 9 species, of which Staphylococcus saprophyticus (37.8%) and Staphylococcus carnosus (15.9%) were the most prevalent. Antimicrobial susceptibility tests showed resistance phenotypes to antibiotics widely administered in humans, such as gentamicin, tetracycline, chloramphenicol, and erythromycin. The coa gene was detected in 19.5% (16/82) of the strains and 4 polymorphic DNA fragments were observed. Five CoNS isolates carrying the coa gene were submitted for 16S rRNA sequencing and 3 showed similarity with CoNS. Forty strains were positive for at least 1 enterotoxin-encoding gene, the genes most frequently detected were sea (28.6%) and seb (27.5%). CONCLUSIONS: The presence of antimicrobial resistant and enterotoxin-encoding genes in staphylococci isolates from black pudding indicated that this fermented food may represent a potential health risk, since staphylococci present in food could cause foodborne diseases or be a possible route for the transfer of antimicrobial resistance to humans