RESUMO
A simple, precise, rapid and accurate HPLC method for the determination of sildenafil citrate (SLD) in human plasma has been developed based on previous reports, to offer an alternative way to detect and quantify SLD and also to improve some characteristics of the validation process. Chromatography was carried out on a C18 reversed-phase column, using a mixture of acetonitrile: ammonium acetate (0.3 M pH 6.8) (1:1 v/v) as the mobile phase at a flow of 0.750 mL/min. Diazepam was used as an internal standard (IS) and detection was by UV at 240 nm. Samples were extracted with 200 microl of 0.1 M Na2CO3 and 5 mL of diethyl ether: dichloromethane (60:40). Retention times of SLD and IS were 4.8 and 7.1 min, respectively; total run time was 10 min. The linear range of SLD was found to be 20 - 1000 ng/mL. Limit of quantitation (LOQ) and limit of detection (LOD) were calculated to be 10 and 20 ng/mL, respectively. An improved percentage recovery of analyte is reported, showing a fast and reproducible approach to detect SLD in plasma human sample. The method was validated for its linearity, precision, accuracy, recovery, stability and specificity.
Assuntos
Inibidores de Fosfodiesterase/sangue , Piperazinas/sangue , Sulfonas/sangue , Calibragem , Cromatografia Líquida de Alta Pressão , Humanos , Soluções Farmacêuticas/análise , Purinas/sangue , Controle de Qualidade , Reprodutibilidade dos Testes , Citrato de Sildenafila , Manejo de Espécimes , Espectrofotometria Ultravioleta , Comprimidos/análiseRESUMO
This study compares the detection of Mycobacterium tuberculosis through bacilloscopy (Ziehl-Neelsen stain), growth in Lowenstein-Jensen medium, and polymerase chain reaction (PCR) carried out with DNA taken directly from various types of samples. A total of 252 samples were analyzed (114 sputum, 96 urine, 15 cerebrospinal fluid, and 27 of other types) from 160 patients with any form of suspected tuberculosis who came to the Clinical Pathology Laboratory of the Specialties Hospital of the Western National Medical Center of the Mexican Social Security Institute. In all cases Ziehl-Neelsen stains were done, as were also cultures with Lowenstein-Jensen medium and PCR amplification of a segment of 285 base pairs specific to the M. tuberculosis complex. Of the 252 samples, with the culture, 18 were positive for nontuberculous mycobacteria. Of the 234 others, 12 (5.1%) were positive with the PCR and the culture, 174 (74.4%) negative in both tests, 47 (20.1%) positive with the PCR and negative with the culture, and 1 (0.4%) negative with the PCR and positive with the culture. Using the culture as the reference test, the PCR provided a sensitivity of 92.3%, a specificity of 78.7%, a positive predictive value of 20.3%, and a negative predictive value of 99.4%. The PCR detection limit with DNA taken from culture was 10 fg, equivalent to four or five mycobacteria. Also in comparison with the culture, the PCR correctly identified the totality of the mycobacteria of the M. tuberculosis complex. Taking the culture as the reference test, when analyzing just the sputum samples, the direct PCR provided a sensitivity of 90.9%, a specificity of 89.5%, a positive predictive value of 52.6%, and a negative predictive value of 98.7%. The PCR is a sensitive and specific technique for detecting the M. tuberculosis complex in both positive and negative bacilloscopy samples. A controlled PCR procedure makes it possible to establish or to exclude the diagnosis of tuberculosis in a time that is reduced from more than three weeks to just 24 to 48 hours. This is particularly useful when an early diagnosis is needed to establish a patient's prognosis or in organ transplant cases.
Assuntos
DNA Bacteriano/análise , Mycobacterium tuberculosis/isolamento & purificação , Reação em Cadeia da Polimerase , Técnicas Bacteriológicas , Líquido Cefalorraquidiano/microbiologia , DNA Bacteriano/genética , Humanos , Mycobacterium tuberculosis/genética , Sensibilidade e Especificidade , Escarro/microbiologia , Fatores de Tempo , Tuberculose/diagnósticoRESUMO
Besides diabetic patients are controlled with glycosylated hemoglobins not exceeding 7% and the normalization of blood pressure with some hypotensive drugs, it has been noted the important role of protein restriction in diet in order to retard nephropathy progression. For some years, various aldose reductase inhibitors (ARIs) have been used, which avoid the accumulation of sorbitol in tissues as well as complications. Platelet antiaggregants are also used for the treatment of diabetic nephropathy, but at a lower level.
Assuntos
Nefropatias Diabéticas/terapia , Aldeído Redutase/antagonistas & inibidores , Dieta com Restrição de Proteínas , Inibidores Enzimáticos/uso terapêutico , Humanos , Hipolipemiantes/uso terapêutico , Inibidores da Agregação Plaquetária/uso terapêuticoRESUMO
Diabetic nephropathy is the third cause of renal failure after pyelonephritis and glomerulonephritis. Lately, many efforts have been made for the early identification (on the silent stage) of patients with a high risk of developing this disease. On these initial stages, therapeutic attitude has changed very much, emphasizing nowadays the importance of glucose levels control, avoiding maintained conditions of hyperglycemia and maintaining blood pressure within the limits, by using the therapeutic store available, basically calcium antagonists and angiotensin-converting enzyme inhibitors.