Recombinogenic, genotoxic, and cytotoxic effects of azathioprine using in vivo assays.

Azathioprine (Aza) is a purine antimetabolite immunosuppressant that is widely employed for immunosuppressive therapy in post-transplant recipients or patients with autoimmune diseases. Chronic use of immunosuppressants might produce several side effects, including a high rate of neoplasms in these patients. Considering that genotoxic effects are associated with an increased risk of developing cancer, the aim of this study was to examine the recombinogenic, genotoxic, and cytotoxic effects of Aza using Somatic Mutation and Recombination Test (SMART) in Drosophila melanogaster, as well as comet and micronucleus assays in mouse bone marrow cells. Further, the adverse effects of Aza were determined in mouse hepatic and renal tissues using histopathological analysis. Data demonstrated that Aza induced significant increased genotoxicity in D. melanogaster and mouse bone marrow cells at all concentrations tested. Homologous recombination was the predominant genotoxic event noted for the first time to be initiated by Aza in SMART. In histopathological analysis, Aza did not show any marked toxic activity in mouse hepatic and renal tissues. Therefore, the high rate of neoplasms reported in patients with long-term use of Aza may be attributed, at least partially, to the genotoxic action of this drug.

Immunostimulating activity of Uncaria tomentosa in RAW 264.7 macrophages.

Uncaria tomentosa is a plant native to the Amazon that has immunomodulatory and antitumor properties due to the alkaloids found in the plant, being able to modify the immune response by potentiating or suspending the action of cytokines secreted by macrophages that induce the immune response, either by the classical route (M1) or through the alternative route (M2). Macrophages activated by M1 convert L-arginine into L-citrulline and nitric oxide (NO), whereas macrophages activated by the M2 pathway use the enzymatic activity of arginase to convert the same substrate into L-ornithine and urea. The aim of this work was to evaluate the immunostimulating activity of the crude hydroalcoholic extract from the bark of the U. tomentosa stem in RAW 264.7 macrophages. Concentrations of 0.2, 0.1 and 0.05 mg/mL of U. tomentosa extract associated with LPS, INF-γ and IL-4 inducers were tested by determining NO production and arginase enzyme activity. Nitric oxide production was enhanced by the extract when associated with LPS and LPS + INF-γ inducers. In the activity of the arginase enzyme, the extract decreased the stimulation of IL-4 on the enzyme, mainly at 0.2 mg/mL concentration. Therefore, it is concluded that the crude hydroalcoholic extract of the stem bark of U. tomentosa in RAW 264.7 cells, at a concentration of 0.2 mg/mL, showed considerable pro-inflammatory activity.

Toxicity and genotoxicity induced by abacavir antiretroviral medication alone or in combination with zidovudine and/or lamivudine in Drosophila melanogaster.

Abacavir (ABC), zidovudine (AZT), and lamivudine (3TC) are nucleoside analog reverse transcriptase inhibitors (NRTIs) widely used as combination-based antiretroviral therapy against human immunodeficiency virus. Despite effective viral suppression using NRTI combinations, genotoxic potential of NRTIs can be increased when administered in combination. This study investigated the toxic and genotoxic potential of ABC when administered alone or in combination with AZT and/or 3TC using the somatic mutation and recombination test in Drosophila melanogaster. This test simultaneously evaluated two events related to carcinogenic potential: mutation and somatic recombination. The results indicated that ABC was responsible for toxicity when administered alone or in combination with AZT and/or 3TC. In addition, all treatment combinations increased frequencies of mutation and somatic recombination. The combination of AZT/3TC showed the lowest genotoxic activity compared to all combinations with ABC. Therefore, our results indicated that ABC was responsible for a significant portion of genotoxic activity of these combinations. Somatic recombination was the main genetic event observed, ranging from 83.7% to 97.7%.

Multidrug-resistant Escherichia coli isolated from a dog with a history of urolithiasis: case report / Escherichia coli multirresistente isolada de cão com histórico de urolitíase: relato de caso

Bacterial resistance is a reality in both human and veterinary health, it limits the therapeutic arsenal and raises the costs of the patient's treatment. A dog with signs of cystitis received treatment with 5mg/kg enrofloxacin at three consecutive times, with low effectiveness. The presence of urethral uroliths was identified and urohydropulsion was done. The animal presented a new obstruction, for which a cystotomy was performed, but continued with signs of infection. Uroculture and antimicrobial susceptibility test were then performed. Escherichia coli was identified, which was resistant to 13 antibiotics, being sensitive only to piperacillin-tazobactam and amikacin. In the screening test for ß-lactamase, the production of ESßL was detected. The qPCR indicated the presence of the bla CTXm, bla DHA, bla OXA, bla IMP, bla TEM, bla GIM, bla SIM, bla SPM and bla SME genes, which may lead to a phenotypic resistance profile for ampicillin, amoxicillin-clavulanate, aztreonam, cefepime cefoxitin, cefuroxime, ceftazidime, ceftriaxone, imipenem, and piperacillin-tazobactam. This case reaffirms the value that laboratory analysis adds to the diagnosis and treatment of cystitis and urolithiasis, which can define the direction of evolution of the prognosis and the speed at which the patient's health will be restored.(AU)

A resistência bacteriana aos antibióticos é uma realidade, tanto na saúde humana quanto veterinária, limita o arsenal terapêutico e eleva os custos relacionados ao tratamento do paciente. Um cão, com sinais de cistite, recebeu tratamento com enrofloxacina, na dose de 5mg/kg, em três momentos seguidos, com baixa efetividade. Identificou-se presença de urólitos uretrais e foi feita uro-hidropropulsão. O animal apresentou nova obstrução, para a qual foi realizada uma cistotomia, mas continuou com sinais de infecção. Realizou-se, então, urocultura e teste de antibiograma. Foi identificada Escherichia coli, que se mostrou resistente a 13 antibióticos, sendo sensível somente à piperacilina-tazobactam e amicacina. No teste de triagem para ß-lactamase, detectou-se a produção de ESßL. A qPCR indicou presença dos genes blaCTXm, blaDHA, blaOXA, blaIMP, blaTEM, blaGIM, blaSIM, blaSPM e blaSME, que podem conduzir um perfil fenotípico de resistência para ampicilina, amoxicilina-ácido clavulânico, aztreonam, cefepima, cefoxitina, cefuroxima, ceftazidima, ceftriaxona, imipenem, piperacilina-tazobactam. Este caso reafirma o valor que a análise laboratorial agrega ao diagnóstico e tratamento da cistite e da urolitíase, podendo definir o sentido de evolução do prognóstico e a velocidade em que a saúde do paciente será restabelecia.(AU)