Fifteen pediatric patients as well as the five nursing staff of the Burn Unit of the Hospital D. Estefania in Lisbon, Portugal, were assayed at weekly intervals over a five-month period in order to identify the nature and number of methicillin-resistant Staphylococcus aureus (MRSA) clones associated with colonization and wound infection. Methicillin resistance was confirmed by a mec-specific DNA probe. MRSA isolates were classified into chromosomal types (clones) on the basis of a variety of techniques: (i) ribotyping; (ii) restriction digestion by the endonuclease ClaI followed by Southern hybridization with the mecA-specific DNA probe and (iii) by hybridization with Tn554; and (iv) pulsed-field electrophoresis (PFE) of SmaI digests followed by (v) Southern hybridization with the mecA DNA probe. A sixth, physiological technique (population analysis) was used to define the mode of phenotypic expression of methicillin resistance in each isolate. All isolates carried a single, common polymorph (ClaI type III) of the mecA gene. Hybridization with Tn554 resolved these isolates to two novel patterns (alpha and beta), of which one (Tn554 alpha) was predominant (90%). This pattern could be further resolved to four closely related PFE types (A through D). In contrast, all isolates with the Tn554 beta pattern belonged to an additional, grossly different PFE type E. The Tn554 beta class was also unique in that these bacteria carried the mecA gene in a SmaI fragment smaller (about 170 kb) than that found in the alpha type strains (194 kb). Most isolates (83%) showed a single heterogeneous (population analysis Class 3) mode of resistance expression. The data demonstrate the full capacity of the globally rare (ClaI type III) MRSA clone for colonization and virulence. The results also document the stability of the complex heterogeneous resistance phenotype as well as the stability of the chromosomal types under conditions of in vivo carriage over a period of several months. In a few isolates the same mecA polymorph was present in several, grossly different genetic backgrounds, suggesting horizontal transfer of the mecA gene.

Prevalência e fatores associados a amputações por pé diabéticoThe prevalence and factors associated with diabetic foot amputations

A new family of 99mTc(I)- tricarbonyl complexes and 125I-heteroaromatic compounds bearing an acridine orange (AO) DNA targeting unit was evaluated for Auger therapy. Characterization of the DNA interaction, performed with the non-radioactive Re and 127I congeners, confirmed that all compounds act as DNA intercalators. Both classes of compounds induce double strand breaks (DSB) in plasmid DNA but the extent of DNA damage is strongly dependent on the linker between the Auger emitter (99mTc or 125I) and the AO moiety. The in vitro evaluation was complemented with molecular docking studies and Monte Carlo simulations of the energy deposited at the nanometric scale, which corroborated the experimental data. Two of the tested compounds, 125I-C5 and 99mTc-C3, place the corresponding radionuclide at similar distances to DNA and produce comparable DSB yields in plasmid and cellular DNA. These results provide the first evidence that 99mTc can induce DNA damage with similar efficiency to that of 125I, when both are positioned at comparable distances to the double helix. Furthermore, the high nuclear retention of 99mTc-C3 in tumoral cells suggests that 99mTc-labelled AO derivatives are more promising for the design of Auger-emitting radiopharmaceuticals than the 125I-labelled congeners.

We present the combination of the clinically well-proven chemotherapeutic agent, Doxorubicin, and (99m)Tc, an Auger and internal conversion electron emitter, into a dual-action agent for therapy. Chemical conjugation of Doxorubicin to (99m)Tc afforded a construct which autonomously ferries a radioactive payload into the cell nucleus. At this site, damage is exerted by dose deposition from Auger radiation. The (99m)Tc-conjugate exhibited a dose-dependent inhibition of survival in a selected panel of cancer cells and an in vivo study in healthy mice evidenced a biodistribution which is comparable to that of the parent drug. The homologous Rhenium conjugate was found to effectively bind to DNA, inhibited human Topoisomerase II, and exhibited cytotoxicity in vitro. The collective in vitro and in vivo data demonstrate that the presented metallo-conjugates closely mimic native Doxorubicin.

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A set of structurally related Ru(η(5)-C5H5) complexes with bidentate N,N'-heteroaromatic ligands have been evaluated as prospective metallodrugs, with focus on exploring the uptake and cell death mechanisms and potential cellular targets. We have extended these studies to examine the potential of these complexes to target cancer cell metabolism, the energetic-related phenotype of cancer cells. The observations that these complexes can enter cells, probably facilitated by binding to plasma transferrin, and can be retained preferentially at the membranes prompted us to explore possible membrane targets involved in cancer cell metabolism. Most malignant tumors present the Warburg effect, which consists in increasing glycolytic rates with production of lactate, even in the presence of oxygen. The reliance of glycolytic cancer cells on trans-plasma-membrane electron transport (TPMET) systems for their continued survival raises the question of their appropriateness as a target for anticancer drug development strategies. Considering the interesting findings that some anticancer drugs in clinical use are cytotoxic even without entering cells and can inhibit TPMET activity, we investigated whether redox enzyme modulation could be a potential mechanism of action of antitumor ruthenium complexes. The results from this study indicated that ruthenium complexes can inhibit lactate production and TPMET activity in a way dependent on the cancer cell aggressiveness and the concentration of the complex. Combination approaches that target cell metabolism (glycolytic inhibitors) as well as proliferation are needed to successfully cure cancer. This study supports the potential use of some of these ruthenium complexes as adjuvants of glycolytic inhibitors in the treatment of aggressive cancers.

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Background: Diabetes and the problem of the diabetic foot specifically are a severe burden on the public healthcare system. Amputations caused by this condition are still common in our setting (Brazil), although the true magnitude of the problem is not known with certainty. Lower limb amputation rates have come to be seen as an indicator of the quality of preventative care of the diabetic foot. Objective: To identify associations between amputations and factors related to people, to morbidities and to primary care received. Methods: This was a cross-sectional study of a sample of 137 patients with diabetic feet admitted to a large hospital in the city of Recife, Pernambuco, Brazil. Logistic regression analysis was conducted. Results: Associations with amputation were detected for the following variables: age over 60; resident of the Metro zone; income of three minimum salaries or less; presence of gangrene on admission; glycemia ≥ 126 mg/dL; smoking; not receiving information about results of glycemia testing; not having feet examined, and not being given guidance on caring for feet at consultations during the previous year. Conclusions: Factors related to Primary Care, such as time since onset of ulcers, information about results of glycemia testing and lack of guidance on how to care for their feet, were associated with occurrence of lower limb amputations. ResumoContexto: O diabetes e especificamente o problema do pé diabético representam grave adversidade ao sistema de saúde pública. As amputações resultantes deste agravo ainda são frequentes em nosso meio, embora não se conheça ao certo a sua magnitude. A taxa de amputações de membros inferiores tem sido considerada um indicador da qualidade dos cuidados preventivos do pé diabético. Objetivo: Identificar a existência de associação entre amputações e fatores relacionados às pessoas, à morbidade e à atenção básica recebida. Métodos: Estudo transversal que incluiu uma amostra de 137 portadores de pé diabético internados em hospital de grande porte da cidade do Recife. Realizou-se análise de regressão logística. Resultados: Verificou-se associação para as variáveis: idade de 60 anos ou mais; procedência da Região metropolitana; renda de até três salários mínimos; presença de gangrena à admissão; glicemia de 126 mg/ dL ou mais; tabagismo; não receber informação dos resultados da glicemia; não ter os pés examinados, e não receber orientação sobre cuidados com os pés nas consultas do ano anterior. Conclusões: Fatores relacionados à Atenção Básica, tais como o tempo de ocorrência da úlcera, a informação dos resultados do exame de glicemia e a falta de orientação sobre cuidados com os pés, estiveram associados com a ocorrência de amputações de membros inferiores.Palavras-chave: pé diabético; amputação; atenção básica.