Phenolic compounds of Hibiscus sabdariffa and influence of organic residues on its antioxidant and antitumoral properties.

The aim of this study was to evaluate the phenolic and flavonoids contents and the antioxidant and antitumoral activity of leaf and calyx methanolic extracts from Hibiscus sabdariffa (roselle) cultivated with poultry litter and organosuper® under three modes of application. The total phenolic content in the each extract was determined using the Folin-Ciocalteu reagent and for aluminium chloride flavonoids. The antioxidant parameters were analyzed using a 2, 2-diphenyl-1-picrylhydrazyl (DPPH.) free radical scavenging assay. An antitumor colorimetric assay using sulforhodamine B. The highest contents of phenolic and flavonoids were observed in leaf extracts (389.98 and 104.52 mg g-1, respectively) and calyx extracts (474.09 and 148.35 mg g-1, respectively) from plants cultivated with organosuper®, although these values did not differ significantly from those observed for the other treatments. The average IC50 of leaves (43.48 µg mL-1) and calyces (37.15 µg mL-1) demonstrated that both have substances that may contribute to free radical scavenging action. The methanol extract from calyces showed significant selective activity against a leukemia line (K-562), with IC50 values of 0.12 mg mL-1 (organosuper®) and 1.16 mg mL-1 (poultry litter), with concentration-dependent, cytotoxic and cytocidal effects.

Sensitivity to outflow boundary conditions and level of geometry description for a cerebral aneurysm.

Mathematical models, namely the flow boundary conditions, as well as the detail of the bounding geometry, can highly influence the computed flow field. In this work, an anatomically realistic portion of cerebral vasculature with a saccular aneurysm, and its geometric idealisation, are considered. The importance of the geometric description, namely including the side branches or modelling them as holes in the main vessel, is studied. Several approaches to prescribe the outflow boundary conditions at the side branches are analysed, including the traction-free condition, zero velocity (hence neglecting the side-branch), and the coupling with simple zero-dimensional and one-dimensional models. Results of the effects of outflow boundary modelling choice on computed haemodynamic parameters are used to identify appropriateness of the models based on the physical interpretation. Estimated range of error-bars associated to outflow boundary model choice and the level of geometric details are presented for patient-specific computational haemodynamics, and can serve as invitation for future studies. The zero-dimensional and one-dimensional models are shown to provide good representations of the side branches in the case of the clipped geometry.

La importancia del peritaje en el estudio comparativo histomorfológico del esmalte, dentina y cemento de dientes humanos y de otros animales

Los patólogos Médicos y Odontólogos reciben fragmentos mineralizados para que los mismos establezcan su origen, si se trata de dientes humanos o de animales. Estos materiales no permiten la clasificación de la especie cuando los caracteres anatómicos diferenciales se encuentran fragmentados o deteriorados por agentes físicos o químicos. Situación ésta donde se tornan necesarios exámenes histomorfológicos para tal clasificación. El objetivo del presente trabajo es proporcionar soporte científico al estudio de los fragmentos mineralizados, cuando es necesario establecer el origen e individualidad de los mismos. Para el siguiente estudio fueron utilizados cortes histológicos, longitudinales y transversales, por desgaste del esmalte, dentina y cemento dentario de cada mamífero estudiado, y analizados por medio de microscopía de luz. Los resultados demuestran con claridad y precisión que el análisis histomorfológico de las estructuras citadas posibilita la identificación y diferenciación de los géneros estudiados o excluyen la posibilidad de fragmentos dentarios examinados pertenecer al género Homo sapiens.

Pathologist and forensic odontologist receive mineralized fragments to identify their origin, if human or animal teeth. These structures don’t permit the classification of the species when the differential anatomical characters are fragmented or deteriorated by physical or chemical agents, where histomorphological studies are needed for such classification. The purpose of this study is to provide scientifical support to study the mineralized fragments, when it comes to the necessity of the establishment of the origin and individuality of them. For the present study longitudinal and transversal histological cuts by abrasion of the enamel, dentin and cement were utilized and analyzed by means of microscopy. The results have clearly and accurately shown that the histomorphologic analysis of the above-mentioned structures makes either possible to identify and differentiate the gender studied or to exclude the possibility that the dental fragment may belong to the gender Homo sapiens.

Exercise stress testing in healthy subjects during cholinergic stimulation after a single dose of pyridostigmine.

OBJECTIVE: The evaluation, by exercise stress testing, of the cardiorespiratory effects of pyridostigmine (PYR), a reversible acetylcholinesterase inhibitor. METHODS: A double-blind, randomized, cross-over, placebo-controlled comparison of hemodynamic and ventilation variables of 10 healthy subjects who underwent three exercise stress tests (the first for adaptation and determination of tolerance to exercise, the other two after administration of placebo or 45mg of PYR). RESULTS: Heart rate at rest was: 68+/-3 vs 68+/-3bpm before and after placebo, respectively (P=0.38); 70+/-2 vs 59+/-2bpm, before and after pyridostigmine, respectively (P<0.01). During exercise, relative to placebo: a significantly lower heart rate after PYR at, respectively, 20% (P=0.02), 40% (P=0.03), 80% (P=0.05) and 100% (P=0.02) of peak effort was observed. No significant differences were observed in arterial blood pressure, oxygen consumption at submaximal and maximal effort, exercise duration, respiratory ratio, CO2 production, ventilation threshold, minute ventilation, and oxygen pulse. CONCLUSION: Pyridostigmine, at a dose of 45mg, decreases heart rate at rest and during exercise, with minimal side effects and without interfering with exercise tolerance and ventilation variables.

Determination of microcontaminants in sediments by on-line solid-phase extraction-gas chromatography-mass spectrometry.

Two simple and straightforward analytical procedures for the screening of sediment samples are reported. They involve extraction with ethyl acetate or methanol and subsequent analysis by means of gas chromatography-mass spectrometry (GC-MS) using large-volume injection (LVI) or solid-phase extraction (SPE). The latter, which was originally developed for the analysis of aqueous samples, can be used without any modification. In general, 10 ml of organic solvent were added to 2 g of sediment, and the mixture was shaken and allowed to stand overnight. The methanolic extracts were then diluted in water and subjected to preconcentration and analysis using on-line SPE-GC-MS. The ethyl acetate extracts were injected directly into the GC using LVI. Both methods were used for the detection and identification of microcontaminants during a monitoring study of the river Nitra (Slovak Republic). They included polyaromatic hydrocarbons (PAHs), chlorofluorohydrocarbons, alkoxylated and alkylated phenols and benzothiazole derivatives. Semi-quantitative profiles of the contaminants were constructed and provisionally interpreted. The results indicate that SPE-GC-MS, and also LVI-GC-MS, have good potential for a rapid screening of sediment samples and the identification of microcontaminants. The analytical procedures pose no problems, and the on-line set-up is user-friendly.