Cytotoxic screening and antibacterial activity of Withaferin A.

Cancer and bacterial infections are among the leading causes of death worldwide. Plant-derived bioactive compounds constitute promising alternatives for development of new therapeutics. This study aimed at evaluating the biological activity of Withaferin A using 6 tumor cell lines: A549 (lung cancer), U87MG (glioblastoma), SH-SY5Y (neuroblastoma), B16-F10 (mouse melanoma), HeLa (uterine colon cancer) and K562 (chronic myeloid leukemia). In addition, 17 other standard bacterial strains and several multidrug resistant bacteria (MDR) clinical isolates were examined. Cell viability was assessed using the following assays: MTT, neutral red, and dsDNA PicoGreen®. Further, oxidative stress was measured by quantification of reactive oxygen species (ROS) production. The activity against bacteria was determined by the minimum inhibitory concentration (MIC), minimum bacterial concentration (CBM) and antibiofilm activity in the production of strains. Withaferin A was effective, as evidenced by its cytotoxic activity in tumor cell lines, enhanced ROS production in tumor cells and bactericidal and antibiofilm activity. Data demonstrated that Withaferin A may be therapeutically considered as an antitumor and antibacterial agent.

Complexos triazenidos de platina (II): Avaliação in vitro da atividade antibacteriana e citotóxica frente a bactérias e células de medula óssea de pacientes leucêmicos de um hospital escola / Triazenidos complexes of platinum (II): In vitro evaluation of antibacterial and cytotoxic activity against bacteria and bone marrow cells from leukemic patients in a university hospital

Atualmente, apesar da ampla gama de substâncias ativas existentes, progressivamente tem se limitado o arsenal terapêutico disponível na prática clínica, isto se deve, especialmente, pelo surgimento da resistência aos agentes terapêuticos utilizados no tratamento de tumores e infecções bacterianas. Em virtude das diversas propriedades farmacológicas demonstradas pelos triazenos (TZCs), avaliaram-se compostos inéditos na busca de novos agentes biologicamente ativos, estes foram denominados C1 e C2. A atividade antibacteriana foi realizada pelo método convencional da microdiluição em caldo, através da técnica da Concentração Inibitória Mínima (CIM), frente a cepas bacterianas de referência American Type Culture Collection (ATCC) e isolados clínicos com resistência múltipla as drogas (RMD). A citotoxicidade foi analisada através do ensaio colorimétrico baseado na redução do brometo de 3-(4,5-dimetiltiazol-2-il)-2,5?difeniltetrazólio frente a células da medula óssea de dois pacientes (P1 e P2) atendidos no Hospital Universitário de Santa Maria. Os dois compostos testados apresentaram atividade antibacteriana em 26,08% (6/23) das cepas testadas, sendo ativos em 38,46% (5/13) das cepas ATCC e 10% (1/10) dos isolados clínicos RMD, apenas em espécies caracterizadas como Gram positivas. Os resultados foram satisfatórios para ambos os compostos frente à amostra P2, células mononucleares de Leucemia Mielóide Crônica, pois demonstraram indução da morte celular. Pode-se concluir que os resultados obtidos desses compostos demonstraram a existência de atividade antibacteriana, bem como, atividade antileucêmica promissora. Pesquisas complementares relacionadas a esses compostos estão em andamento.(AU)

Currently, despite the wide range of existing active substances has been progressively limited therapeutic arsenal available in clinical practice, this is, in particular, the emergence of resistance to therapeutic agents used in treating tumors and bacterial infections. Because of the diverse pharmacological properties demonstrated by triazenes (TZCs) - evaluated whether unpublished compounds in the search for new biologically active agents, they were called C1 and C2. The antibacterial activity was performed by the conventional method of broth microdilution, using the technique of Minimum Inhibitory Concentration (MIC) against the bacterial strains reference American Type Culture Collection (ATCC) and clinical isolates with multiple drug resistance (MDR). Cytotoxicity was analyzed by colorimetric assay based on the reduction of the bromide of 3 - (4,5- dimethylthiazol-2- yl) -2,5- diphenyltetrazolium against bone marrow cells from two patients (P1 and P2) seen at the Hospital university of Santa Maria. The two compounds tested showed antibacterial activity in 26.08% (6/23) of the strains, being active in 38.46 % (5/13) of the ATCC strains and 10 % (1/10) of clinical isolates MDR only characterized in species such as Gram positive. The results were satisfactory for both the sample compounds front P2, mononuclear cells from chronic myeloid leukemia, as demonstrated induction of cell death. It can be concluded that the results demonstrated the existence of these compounds to antibacterial activity, as well as promising antileukemic activity. Additional research related to these compounds are in progress.(AU)

Avaliação do Desempenho de Culturas Convencionais na Detecção da Contaminação Bacteriana em Concentrados Plaquetários em um Hospital Universitário do Sul do Brasil / Assessment of performance of conventional culture in the detection of bacterial contamination in platelet concentrates in a University Hospital in southern Brazil

Blood transfusion is an indispensable aid to the treatmentof cancer patients. On the other hand, it involves a seriousrisk of bacterial sepsis. Platelet concentrates (PCs) arethe blood components with the highest incidence ofbacterial contamination, being responsible for mostof the septic reactions to transfusion. In this study, weassessed various conventional culture methods for thedetection of bacterial contamination in PCs. In all, 691samples of PCs (665 random donor platelets and 26apheresis platelets) from the Blood Center of the Stateof Rio Grande do Sul (HEMORGS), were analyzed. Weemployed qualitative, quantitative and daily growthculture techniques, which revealed that 2.32% of thesamples analyzed, all from random donor platelets, werecontaminated. The qualitative methodology performedbest. This result obliges us to reinforce the importanceof performing pre-transfusion bacteriological screeningon all samples of PCs, to reduce the risk of sepsis.

As transfusões sanguíneas retratam um suporte indispensável no tratamento de pacientes com câncer. Por outro lado, representam um sério risco de sepse bacteriana. Os concentrados plaquetários (CPs) são os hemocomponentes com a mais alta frequência de contaminação bacteriana, responsáveis pela maioria das reações sépticas transfusionais. Este estudo objetivou avaliar diferentes metodologias convencionais de cultura na detecção da contaminação bacteriana em CPs. Um total de 691 amostras de CPs (665 plaquetas randômicas e 26 plaquetaféreses), provenientes do Hemocentro do Estado do Rio Grande do Sul (HEMORGS), foi analisado. Foram empregadas técnicas de cultura qualitativa, quantitativa e de crescimento diário, com as quais evidenciamos 2,32% de contaminação bacteriana nas amostras analisadas, sendo todas provenientes de coleta pelo método randômico. A metodologia qualitativa apresentou o melhor desempenho. Esse fato nos permite reforçar a importância da realização de triagem bacteriológica pré-transfusional em todas as amostras de CPs para a redução dos riscos de sepse.

Interference in the Limulus amebocyte lysate assay for endotoxin determination in peritoneal dialysis fluids and concentrates for hemodialysis.

The interference of the saline concentration of fluids for peritoneal dialysis and concentrates for hemodialysis on the Limulus amebocyte lysate (LAL) assay for endotoxins was investigated. The experiments were carried out individually with each substance that compose fluids for hemodialysis, to determine the possible inhibition or enhancement effects that they could cause on the LAL assay. The compositions were also assayed to investigate the possibility of synergistic effect. They were assayed by the gel-clot method from two different suppliers, and the samples that showed inhibition effect were also assayed by the chromogenic method. The samples were analysed at successive dilutions, with different LAL sensitivities, to satisfy the endotoxin limits of 5 EU/ml for the concentrate and 0.25 EU/ml for the fluid for dialysis peritoneal. The results showed that the major interference on the gel-clot assay occurs in presence of acetic acid and in concentrates containing acid acetic, even the pH being adjusted between 6.5 and 7.5. However, the test, after an adequate dilution, could be validating for all samples. Chromogenic test can be used for peritoneal dialysis fluids considering a limit of 0.25 EU/ml and sample dilution of eight times, but it cannot be used for concentrates for hemodialysis without further dilution. Considering the results and that the chromogenic is a more time-consuming method, endotoxins in fluids for hemodialysis can be satisfactorily assayed by the gel-clot method.

Identificação do complexo Mycobacterium tuberculosis isolado de pacientes do Hospital Universitário de Santa Maria, RS / Mycobacterium tuberculosis complex isolated of patients of University Hospital of Santa Maria, RS

A OMS tem enfatizado o alarmante aumento dos casos de tuberculose (TB) no mundo. O Brasil carece de dados representativos, pois enquanto algumas regiões mantêm a prevalência constante, em outras, como nos grandes centros urbanos, observa-se nítido aumento. Nastas circunstâncias, relatamos o número de casos de tuberculose, diagnosticados com base na cultura, no Hospital Universitário de Santa Maria (RS). Em 1996 foram realizados 476 cultivos para micobactérias no meio clássico de Lowenstein-Jensen, dos quais 42 (8,8 por cento) resultaram positivos. utilizando-se o método comercial MTBAC (PROBAC), que envolve provas de resistência do ácido tiofeno-2-carboxílico (TCH), resistência ao ácido paranitrobenzóico (PNB), produção de niacina e redução do nitrato, foram identificados 30 como M. tuberculosis, um como M. bovis e dois não-pertencentes ao tuberculosis complex