RESUMO
Biopterin, isoxanthopterin and 6-pterincarboxylic acid were identified in the head of the malaria vector mosquito Anopheles albimanus Weidemann (Diptera: Culicidae) by HPLC. Total pteridine concentrations (TPC) were estimated in heads, body parts (BP: abdomen, legs and wings) and whole bodies of insectary-reared and field-collected females, by spectrofluorometry, to investigate whether they could be used for age determination. Pteridine concentrations diminished with age in both mosquito groups. TPC correlated with chronological age in insectary-reared sugar-fed females (heads: r2 = 0.35, BP: r2 = 0.34, P < 0.001), but lower correlation occurred in blood-fed females (heads: r2 = 0.22, BP: r2 = 0.27). TPC differed among females of the same age fed with blood at different times (P < 0.05), indicating that bloodmeals modify the diminution rate of pteridines with age. Nevertheless, a polynomial significant correlation was documented for TPC and the number of ovipositions (heads: r2 = 0.24, BP: r2 = 0.27, whole body: r2 = 0.52, P < 0.001) in insectary-reared mosquitoes. This correlation was lower in field-collected mosquitoes (heads: r2 = 0.14, BP: r2 = 0.10, P < 0.05), which showed a remarkable pteridine increase in one-parous females. The correlation of TPC in whole body with physiological age was much less (r2 = 0.03). These observations indicate that TPC determination by spectrofluorometry is not a reliable method to estimate the age of An. albimanus females from the feral population.
Assuntos
Envelhecimento/fisiologia , Anopheles/química , Anopheles/fisiologia , Pteridinas/análise , Abdome , Criação de Animais Domésticos , Animais , Animais Selvagens , Constituição Corporal , Cromatografia Líquida de Alta Pressão , Dieta , Extremidades , Feminino , Cabeça , Insetos Vetores/química , Insetos Vetores/fisiologia , Malária , Ovário/fisiologia , Oviposição/fisiologia , Pteridinas/química , Asas de Animais/químicaRESUMO
The methods accepted to determine antimicrobial drug susceptibility of mycobacteria are based on the determination of the microorganisms' growth on solid or liquid medium containing a specified concentration of a single drug.
RESUMO
BACKGROUND: Entamoeba histolytica forms cyst-like structures (CLS) in PEHPS but not in TYS-33 medium. Sodium dodecyl sulfate [(SDS (0.1%)] dissolves most of them in 10 min, but not natural cysts. Chitin is responsible mainly for cyst wall resistance. Its synthesis depends on Mg(2)+, Mn(2)+, or Co(2)+, whose action is interactive. With the aid of the Simplex method, we analyzed the effect of 20 blends of these cations to find the one that, when added to PEHPS, produced the highest proportion of CLS resistant to 1% SDS (RCLS). METHODS: The concentration of Mg(2)+, Mn(2)+, and Co(2)+ was determined in PEHPS and TYI-S-33 with a flame atomic absorption spectrometer. The proportion of RCLS produced in PEHPS with each ion blend was tested. The CLS and RCLS affinity to fluorescein wheat germ agglutinin (WGA/FITC), which binds chitin, was determined. RESULTS: PEHPS contained a similar concentration of Co(2)+ (0.52 microM) and 3.4 and 1.6 times more Mg(2)+ (798 microM) and Mn(2)+ (3.15 microM) than TYI-S-33, respectively. The proportion of RCLS increased gradually in PEHPS until reaching 3.6 +/- 1.43% with MgCl(2) 1.22 mM, MnCl(2) 14.44 mM, and CoCl(2) 19.44 mM (ion blend No. 20). Both CLS and RCLS bound WGA/FITC. The RCLS formed in the presence of ion blend No. 20 appeared wrinkled. CONCLUSIONS: Mg(2)+, Mn(2)+, and Co(2)+ enhanced the ability of PEHPS to form RCLS, possibly because these ions stimulated their chitin synthesis. Although ion blend No. 20 produced the highest proportion of RCLS, this high ion concentration may be toxic for encysting amebas.
Assuntos
Cobalto/farmacologia , Entamoeba histolytica/efeitos dos fármacos , Magnésio/farmacologia , Manganês/farmacologia , Dodecilsulfato de Sódio/farmacologia , Animais , Quitina/biossíntese , Cobalto/análise , Meios de Cultura/farmacologia , Resistência a Medicamentos , Entamoeba histolytica/crescimento & desenvolvimento , Entamoeba histolytica/ultraestrutura , Magnésio/análise , Manganês/análise , Microscopia de FluorescênciaRESUMO
In the present work a rapid method to determine the susceptibility of Mycobacterium tuberculosis to isoniazid and streptomycin by determining levels of mycolic acids by high-performance liquid chromatography (HPLC) was developed. Mycobacterial growth kinetics in the presence and absence of antituberculosis drugs was characterized by evaluating the total area corresponding to mycolic acid peaks (TAMA). Results show a linear relationship between the logarithm of CFU per milliliter and TAMA and show that it is possible to detect growth inhibition of M. tuberculosis in the presence of isoniazid or streptomycin by using HPLC in 3 and 4 days, respectively.
Assuntos
Antibióticos Antituberculose/farmacologia , Testes de Sensibilidade Microbiana , Mycobacterium tuberculosis/efeitos dos fármacos , Ácidos Micólicos/análise , Cromatografia Líquida de Alta PressãoRESUMO
T-514 is a toxic substance of Karwinskia humboldtiana which has been described as a possible anticancer agent. An animal model (New Zeland white rabbit) was selected for pharmacokinetic studies that would allow the performance of surgical techniques to catheterize central vessels in order to obtain blood samples at short time intervals. A nonlinear regression analysis method was used to fit the plasmatic concentration data to a multiexponential mathematical function; a computer program based on Marquant's iterating algorithm was used to fit the experimental curves. In the present work we show the advantage of introducing two catheters of different diameters in the jugular vein using modifications of the Seldinger and Braunüle techniques: a catheter of small diameter (18 G) is used to introduce the drug and a larger one (16 G) to sample at different times. The larger diameter catheter facilitates a rapid sampling of blood (two mL/s) which is essential to determine the initial phase of the distribution process (alpha phase). The behavior of T-514 corresponded to a two-compartment model with a biexponential equation C = 0.35 e-0.13(t-2) + 0.17 e-0.03(t-2).