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Background: Tarantula cubensis venom (Theranekron®) is used as a homeopathic medicine which has shown anti-tumor effects in veterinary medicine. The aim of this study was to assess effect of Tarantula cubensis venom on apoptotic cell death of human cancer cell lines. Methods: HEK293, MCF7 and HN5 cell lines were used. The cells were treated with different concentrations of alcoholic extract of Tarantula cubensis (Theranekron®) for different periods of time. Cell morphology was studied by light microscopic observation. Cell proliferation was evaluated by MTT assay and death rate was assessed applying trypan blue staining. Apoptosis was assessed by DNA fragmentation, cleaved caspase-3 protein western blotting and ELISA caspase-3 activity assays. Results: Tarantula cubensis venom ruined cell adhesion, reduced cell proliferation, increased cell death rates and caused DNA fragmentation in human cells. An increased caspase-3 cleavage and hyper-activation of caspase-3 was detected in the cells treated with the venom. Results also showed a significantly higher toxicity and apoptosis levels in cancer cell lines MCF7 and HN5 compared with non-cancerous HEK293 cells. Conclusion: We conclude that Tarantula cubensis venom is selectively toxic for human cancer cells via inducing caspase-3- mediated apoptosis.
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Objective: To check biofilm formation by Acinetobacter baumannii (A. baumannii) clinical isolates and show their susceptibility to different antibiotics and investigate a possible link between establishment of biofilm and multidrug resistance. Methods: This study was performed on clinical samples collected from patients with nosocomial infections in three hospitals of Tehran. Samples were initially screened by culture and biochemical tests for the presence of different species of Acinetobacter. Iden-tifications were further confirmed by PCR assays. Their susceptibilities to 11 antibiotics of different classes were determined by disc diffusion method according to Clinical and Laboratory Standards Institute guidelines. The ability to produce biofilm was investigated using methods:culture on Congo red agar, microtiter plate, and test tube method. Results: From the overall clinical samples, 156 specimens were confirmed to contain A. baumannii. The bacteria were highly resistant to most antibiotics except polymyxin B. Of these isolates, 10.26% were able to produce biofilms as shown on Congo red agar. However, the percentage of bacteria with positive biofilm in test tube, standard microtiter plate, and modified microtiter plate assays were 48.72%, 66.66%, and 73.72%, respec-tively. At least 92%of the biofilm forming isolates were multidrug resistant. Conclusions: Since most of the multidrug resistant strains produce biofilm, it seems necessary to provide continuous monitoring and determination of antibiotic susceptibility of clinical A. baumannii. This would help to select the most appropriate antibiotic for treatment.
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Designing newer drugs, vaccines, and diagnostic techniques is dependent on better understanding of M. tuberculosis virulence mechanism. In this study the prevalence of pcaA gene was determined in M. tuberculosis strains typed by spoligotyping. The associated risk factors among patients with different nationalities residing in Iran were also determined. The isolated M. tuberculosis strains have been characterized by performing susceptibility tests against four first-line antituberculosis drugs and were then subjected to spoligotyping characterization. PCR was used for detection of pcaA gene and its nucleotide sequence was also determined. Spoligotyping of M. tuberculosis strains resulted in 140 different patterns. One hundred twenty two (87.1%) of these spoligotype isolates were unique and reported for the first time. The remaining18 (12.8%) spoligotype patterns were previously reported from other geographical regions of the world. Haarlem family was most prevalent than other genotype. Antibiotic resistances were higher in those isolated from the Iranian patients. The pcaA gene was detected in M. tuberculosis clinical isolates but not in saprophyte strains such as M. kansasi. The results showed that, spread of M. tuberculosis strains belonging to the Beijing family among Iranian patients has to be considered seriously. This study confirmed the widespread existenceof pcaA gene in almost all the clinical isolates. It is also important to undertake studiesto identify which factors are the most significant to considerin tuberculosis control program.
O desenvolvimento de novas drogas, vacinas e técnicas de diagnóstico depende de uma melhor compreensão dos mecanismos de virulência de Mycobacterium tuberculosis. Neste estudo, a prevalência do gene pcaA em cepas de M. tuberculosis foi avaliada através de da técnica de spoligotyping. Os fatores de risco associados nos pacientes de diferentes nacionalidades vivendo no Irã foram também determinados. As cepas de M. tuberculosis isoladas foram submetidas a testes de sensibilidade a quatro drogas anti-tuberculose de primeira linha e à caracterização por spoligotyping. Empregou-se PCR para detectar o gene pcaA, determinado-se também a sequencia de nucleotidios. A espoligotipagem resultou em 140 grupos diferentes, sendo 120 (87,1%) reportados pela primeira vez. Os demais espoligotipos (12,8%) já foram descritos em outras regiões geográficas no mundo. A família Haarlem foi mais comum que os demais genótipos. A resistencia a antibióticos foi maior nas cepas isoladas dos pacientes iranianos. O gene pcaA foi detectado em isolados clínicos de M. tuberculosis mas não em cepas saprófitas, como M. kansasi. Os resultados indicaram a existência de M. tuberculosis pertencente à família Beijing nos pacientes iranianos. Este estudo confirmou a presença do gene pcaA em quase todos os isolados clínicos. Estudos que identifiquem os fatores mais significantes nos programas de controle da tuberculose são necessários.