RESUMO
Purification of the total DNA extracted from activated sludge samples was studied. The effects of extraction buffers and lysis treatments (lysozyme, sodium dodecyl sulfate (SDS), sonication, mechanical mill and thermal shock) on yield and purity of the total DNA extracted from activated sludge were investigated. It was found that SDS and mechanical mill were the most effective ways for cell lysis, and both gave the highest DNA yields, while by SDS and thermal shock, the purest DNA extract could be obtained. The combination of SDS with other lysis treatment, such as sonication and thermal shock, could apparently increase the DNA yields but also result in severe shearing. For the purification of the crude DNA extract, polyvinyl polypyrrolidone was used for the removal of humic contaminants. Cetyltrimethyl ammonium bromide, potassium acetate and phenol/chloroform were used to remove proteins and polysaccharides from crude DNA. Crude DNA was further purified by isopropanol precipitation. Thus, a suitable protocol was proposed for DNA extraction, yielding about 49.9 mg (total DNA)/g volatile suspended solids, and the DNA extracts were successfully used in PCR amplifications for 16S rDNA and 16S rDNA V3 region. The PCR products of 16S rDNA V3 region allowed the DGGE analysis (denatured gradient gel electrophoresis) to be possible.
Assuntos
DNA/isolamento & purificação , Esgotos , 2-Propanol/química , Cetrimônio , Compostos de Cetrimônio/química , Quelantes/química , Precipitação Química , Clorofórmio/química , DNA/genética , DNA Bacteriano/genética , Ácido Edético/química , Eletroforese em Gel de Poliacrilamida , Fenol/química , Reação em Cadeia da Polimerase , Acetato de Potássio/química , Povidona/análogos & derivados , Povidona/química , RNA Ribossômico 16S/genética , Dodecilsulfato de Sódio/químicaRESUMO
OBJECTIVE: To study the healing effect of recombinant human epidermal growth factor (hEGF) on diabetic foot ulcers. RESEARCH DESIGN AND METHODS: A total of 127 consecutive patients were screened and 61 diabetic subjects were recruited into this double-blind randomized controlled study. Predetermined criteria were used for diagnosis and classification of the diabetic wound. The patients were randomized into three groups. All patients attended our Diabetes Ambulatory Care Center every other week for joint consultation with the diabetologist and the podiatrist. Group 1 (control) was treated with Actovegin 5% cream (Actovegin), group 2 with Actovegin plus 0.02% (wt/wt) hEGF, and group 3 with Actovegin plus 0.04% (wt/wt) hEGF. The study end point was the complete closure of the wound. Failure to heal was arbitrarily defined as incomplete healing after 12 weeks. RESULTS: Final data were obtained from 61 patients randomly assigned into three groups. The mean ages of the patients, wound sizes, wound duration, metabolic measurements, and comorbidities were comparable within groups, except that group 3 had more female patients. Mean follow-up for the patients was 24 weeks. Data were cutoff at 12 weeks, and results were analyzed by intention to treat. After 12 weeks, in group 1 (control) eight patients had complete healing, two patients underwent toe amputation, and nine had nonhealing ulcers. In group 2 (0.02% [wt/wt] hEGF) 12 patients experienced wound healing, 2 had toe amputations, and 7 had nonhealing ulcers. Some 20 of 21 patients in group 3 (0.04% [wt/wt] hEGF) showed complete wound healing. Healing rates were 42.10, 57.14, and 95% for the control, 0.02% (wt/wt) hEGF, and 0.04% (wt/wt) hEGF groups, respectively. Kaplan-Meier survival analysis suggested that application of cream with 0.04% (wt/wt) hEGF caused more ulcers to heal by 12 weeks and increased the rate of healing compared with the other treatments (log-rank test, P = 0.0003). CONCLUSIONS: Our data support the contention that application of hEGF-containing cream, in addition to good foot care from a multidisciplinary team, significantly enhances diabetic foot ulcer wound healing and reduces the healing time.