Ultrastructural analysis of microfilariae of Wuchereria bancrofti obtained from persistent carriers after repeated courses of diethylcarbamazine

Single dose of diethylcarbamazine (DEC) used in control programs is effective in breaking the transmission of filariasis. In order to investigate the effect of aggressive therapy on Wuchereria bancrofti (Wb) microfilariae, DEC was given to 29 patients who were positive for the circulating filarial antigen (CFA) assay but did not have clinical manifestations of filariasis, at 6 mg/kg/day for 12 days and again six months later using the same dosing regimen. For each patient, microfilarial density and serum CFA were followed up for two years. Ultrastructural analyses on Wb microfilariae obtained after repeated treatment with DEC were also performed. Microfilaremia and antigenemia decreased significantly after 12 months but returned to the initial levels after 24 months. This could indicate, as shown by other authors, that aggressive repeated therapy with DEC alone is ineffective in eradicating adult W. bancrofti, particularly in infected but asymptomatic individuals. The objective of the present study was to analyze the microfilaremic and antigenemic behavior and ultrastructural changes caused by different DEC concentrations in vitro in Wb microfilariae obtained from individuals who were sensitive and refractory to treatment. After in vitro treatment of the microfilariae using 5 and 10 μg/ml of DEC for 1 h, ultrastructural analysis revealed low levels of cell damage compared with embryos obtained from individuals from a different area who had never received DEC treatment before. The results obtained suggest that microfilariae from patients who receive repeated aggressive therapy are less sensitive to DEC in vitro.     

Correlation of the Physicochemical and Structural Properties of pDNA/Cationic Liposome Complexes with Their in Vitro Transfection

In this study, we characterized the conventional physicochemical properties of the complexes formed by plasmid DNA (pDNA) and cationic liposomes (CL) composed of egg phosphatidylcholine (EPC), 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE), and 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) (50/25/25% molar ratio). We found that these properties are nearly unaffected at the studied ranges when the molar charge ratio (R(±)) between the positive charge from the CL and negative charge from pDNA is not close to the isoneutrality region (R(±) = 1). However, the results from in vitro transfection of HeLa cells showed important differences when R(±) is varied, indicating that the relationships between the physicochemical and biological characteristics were not completely elucidated. To obtain information regarding possible liposome structural modifications, small-angle X-ray scattering (SAXS) experiments were performed as a function of R(±) to obtain correlations between structural, physicochemical, and transfection properties. The SAXS results revealed that pDNA/CL complexes can be described as being composed of single bilayers, double bilayers, and multiple bilayers, depending on the R(±) value. Interestingly, for R(±) = 9, 6, and 3, the system is composed of single and double bilayers, and the fraction of the latter increases with the amount of DNA (or a decreasing R(±)) in the system. This information is used to explain the transfection differences observed at an R(±) = 9 as compared to R(±) = 3 and 6. Close to the isoneutrality region (R(±) = 1.8), there was an excess of pDNA, which induced the formation of a fraction of aggregates with multiple bilayers. These aggregates likely provide additional resistance against the release of pDNA during the transfection phenomenon, reflected as a decrease in the transfection level. The obtained results permitted proper correlation of the physicochemical and structural properties of pDNA/CL complexes with the in vitro transfection of HeLa cells by these complexes, contributing to a better understanding of the gene delivery process.     

Chemiluminescent Detection of Carbohydrates in the Tumoral Breast Diseases

Nowadays, there is an increase of investigations into the fibroadenoma, mainly because some studies have shown that the occurrence of fibroadenoma is linked to an increased risk of developing breast carcinoma. Currently, the chemiluminescence biomarkers are applied for validation methods and screening. Here, a lectin chemiluminescence is proposed as new histochemistry method to identify carbohydrates in mammary tumoral tissues. The lectins concanavalin A (Con A) and peanut agglutinin (PNA) conjugated to acridinium ester were used to characterize the glycocode of breast tissues: normal, fibroadenoma, and invasive duct carcinoma (IDC). The lectin chemiluminescence expressed in relative light units (RLU) was higher in fibroadenoma and IDC than in normal tissue for both lectins tested. The relationship RLU emission versus tissue area described a linear and hyperbolic curve for IDC and fibroadenoma, respectively, using Con A whereas hyperbolic curves for both transformed tissues using PNA. RLU was abolished by inhibiting the interaction between tissues and lectins using their specific carbohydrates: methyl-α-d-mannoside (Con A) and galactose (PNA). The intrinsic fluorescence emission did not change with combination of the lectins (Con A/PNA) to the acridinium ester for hydrophobic residues. These results represent the lectin chemiluminescence as an alternative of histochemistry method for tumoral diagnosis in the breast.     

Nitrosation of aryl and heteroaryltrifluoroborates with nitrosonium tetrafluoroborate

Organotrifluoroborates have emerged as an alternative to toxic and air- and moisture-sensitive organometallic species for the synthesis of functionalized aryl and heteroaryl compounds. It has been shown that the trifluoroborate moiety can be easily converted into a variety of different substituents in a late synthetic stage. In this paper, we disclose a mild, selective, and convenient method for the ipso-nitrosation of organotrifluoroborates using nitrosonium tetrafluoroborate (NOBF(4)). Aryl- and heteroaryltrifluoroborates were converted into the corresponding nitroso products in good to excellent yields. This method proved to be tolerant of a broad range of functional groups.     

Bell Nonlocality, Signal Locality and Unpredictability (or What Bohr Could Have Told Einstein at Solvay Had He Known About Bell Experiments)

The 1964 theorem of John Bell shows that no model that reproduces the predictions of quantum mechanics can simultaneously satisfy the assumptions of locality and determinism. On the other hand, the assumptions of signal locality plus predictability are also sufficient to derive Bell inequalities. This simple theorem, previously noted but published only relatively recently by Masanes, Acin and Gisin, has fundamental implications not entirely appreciated. Firstly, nothing can be concluded about the ontological assumptions of locality or determinism independently of each other—it is possible to reproduce quantum mechanics with deterministic models that violate locality as well as indeterministic models that satisfy locality. On the other hand, the operational assumption of signal locality is an empirically testable (and well-tested) consequence of relativity. Thus Bell inequality violations imply that we can trust that some events are fundamentally unpredictable, even if we cannot trust that they are indeterministic. This result grounds the quantum-mechanical prohibition of arbitrarily accurate predictions on the assumption of no superluminal signalling, regardless of any postulates of quantum mechanics. It also sheds a new light on an early stage of the historical debate between Einstein and Bohr.     

Uniform stabilization of the damped Cauchy-Ventcel problem with variable coefficients and dynamic boundary conditions

In this paper, the uniform stabilization of the Cauchy-Ventcel problem with variable coefficients is considered, and the uniform energy decay rate for the problem is established by Riemannian geometry methods.     

Analysis of exemestane and 17β-hydroxyexemestane in human urine by gas chromatography/mass spectrometry: development and validation of a method using MO-TMS derivatives

Trimethylsilylation of anabolic agents and their metabolites is frequently achieved by using the derivatization mixture N-methyl-N-(trimethylsilyl)trifluoroacetamide (MSTFA)/NH(4)I/2-mercaptoethanol. Nevertheless, artifacts were formed when this mixture was employed in the monitoring of exemestane and its main metabolite 17β-hydroxyexemestane prior to GC-MS analysis. These artifacts were identified as the N-methyltrifluoroacetamide (MTFA) and trimethylsiloxyethylmercapto products of the respective trimethylsilyl (TMS) derivatives. Furthermore, artifact formation was evaluated taking the structure (1,4-diene-3-keto-6-exomethylene) of the compounds into account. Although these artifacts are relevant for investigations regarding the derivatization process and may be of interest in many fields, they are detrimental to cope with the requirements of the World Anti-Doping Agency (WADA) in terms of the limits of detection (LODs) required. To overcome this issue, a method using an alternative derivatization was proposed: formation of methyloxime-TMS derivatives through double derivatization using O-methylhydroxylamine/pyridine and MSTFA/TMS imidazole after enzymatic hydrolysis and liquid-liquid extraction. Samples from an excretion study after administration of exemestane to healthy volunteers were analyzed by the proposed method and detection of both exemestane and its main metabolite was possible. This method showed excellent results for both analytes meeting the LODs required for antiestrogenic agents (50 ng/mL) established by WADA. The method was validated for the main metabolite, it was robust and cost-effective for qualitative and quantitative purposes, with LOD and LOQ of 10 ng/mL and 25 ng/mL, respectively.     

Influence of drying processes on oxidative stability of ethyl corn biodiesel by differential scanning calorimetry

The influence of drying processes in the biodiesel oxidation was investigated by means of the oxidative induction time obtained from differential scanning calorimetry data. For this purpose, corn biodiesel was dried by different methods including: chemical (anhydrous sodium sulfate) and thermal (induction heating, heating under vacuum and with microwave irradiation). The drying efficiency was evaluated by monitoring IR absorption in the 3,500–3,200 cm⁻¹ range and by the AOCS Bc 2-49 method. In general, the oxidative induction times increased inversely to the heating degree, except that of microwave irradiation, which was selective to water evaporation and caused low impact over the unsaturation of biodiesel. The DSC technique was shown to be a powerful tool to evaluate with high level of differentiation the influence of the drying process on the oxidative stability of biodiesel.