OBJECTIVE: The study aimed to investigate gyrA and gyrB mutations in Mycobacterium tuberculosis (MTB) clinical strains from 93 patients with pulmonary tuberculosis in Hubei Province, China, and analyze the association between mutation patterns of the genes and ofloxacin resistance level. RESULTS: Among 93 MTB clinical isolates, 61 were ofloxacin-resistant by the proportion method, and 32 were ofloxacin-susceptible MDR-TB. No mutation in the gyrB gene was found in any MTB strains. In the 61 ofloxacin-resistant isolates, 54 mutations were observed in the gyrA gene. Only one mutation in the gyrA gene was found in ofloxacin-susceptible MDR-TB isolates. In this study, the mutation patterns of gyrA involved seven patterns of single codon mutation (A90V, S91P, S91T, D94N, D94Y, D94G or D94A) and two patterns of double codons mutation (S91P & D94H, S91P & D94A). The ofloxacin minimal inhibitory concentrations (MICs) of three patterns of single codon mutations in the gyrA gene (codons 94, 90 and 91) showed a statistically significant difference (p < 0.0001). CONCLUSIONS: The gyrA mutations at codons 90, 91 and 94 constitute the primary mechanism of fluoroquinolone resistance in MTB, and mutations at codon 91 in the gyrA gene may be associated with low-level resistance to ofloxacin.

CXCL-12 and its receptor CXCR4 participate in breast cancer and melanoma cell metastasis to bone and lymphoid nodes. CD44, as a receptor for hyaluronic acid, is involved in lymphocyte recirculation, homing, adhesion and migration. But the role of CD44 in CXCL-12 induced leukemia cell migration still remains unclear. The present study showed that CXCL-12 stimulation induced the rapid internalization of CXCR4 and facilitated the formation of lamellipodia and uropod in acute leukemia cell line HL-60. CXCL-12 also induced CD44 translocation into the uropod, while CD44 remained evenly distributed on the untreated cell membranes. Results suggest that CD44 participates in CXCL-12 induced cell polarization and subsequent cell migration.

Foi desenvolvido um método rápido, de baixo custo e preciso para a determinação de cádmio em sangue integral usando espectrometria de fluorescência atômica com geração de hidreto (HG-AFS). A amostra foi preparada por lixiviação assistida por ultra-som e a solução resultante foi usada diretamente para a determinação do cádmio por HG-AFS. Adotando-se as condições otimizadas para o procedimento proposto, o limite de detecção (LOD) e limite de quantificação (LOQ) foram de 0,08 e 0,26 µg L-1, respectivamente, calculados a partir de três e dez vezes o desvio padrão de onze medidas para a amostra de sangue bovino (branco), com baixo teor de Cd (0,2 µg L-1, diluída por um fator de 10). O desvio-padrão relativo (RSD, n = 7) variou entre 3-10% (entre medidas) para amostras de sangue contendo de 1 a 8 µg L-1 de cádmio. A precisão e aplicabilidade prática do método foram comprovadas analisando-se materiais de referência certificados (MRCs). Os resultados foram ainda comparados com aqueles obtidos por espectrometria de massa com fonte de plasma indutivamente acoplado (ICP-MS). Uma boa concordância foi observada entre os resultados obtidos por HG-AFS e ICP-MS para a determinação de cádmio em MRCs e em amostras de sangue humano.

A rapid, low cost and precise method was developed for the determination of cadmium in whole blood using hydride generation atomic fluorescence (HG-AFS). Sample was simply prepared utilizing ultrasound-assisted leaching and the resulting solution was directly used for cadmium determination by HG-AFS. Adopting optimized conditions, the limit of detection (LOD) and limit of quantification (LOQ) of the proposed procedure were 0.08 and 0.26 µg L−1, calculated from three and ten times the standard deviations of eleven runs of blank blood sample (bovine blood) with low Cd content (0.2 µg L−1 Cd, tenfold diluted); and the relative standard deviation (RSD, n = 7) varied between 3-10% (between-run) at 1-8 µg L−1 cadmium level in blood. The accuracy and practical applicability of the method were validated by analyzing certified reference materials (CRMs) and further demonstrated by results comparison with inductively coupled plasma masss spectrometry (ICP-MS). Good agreement has been demonstrated between results obtained by HG-AFS and ICP-MS for cadmium determination in CRMS and human whole blood.