Correlation between heart rate control during exercise and exercise capacity in patients with chronic atrial fibrillation.

BACKGROUND: Rate control is an acceptable alternative to rhythm control in patients with chronic atrial fibrillation (AF). HYPOTHESIS: The aim of this study of AF patients was to understand the correlation between their exercise capacity and both heart rate (HR) and HR variation index during exercise. METHODS: The exercise capacity of 85 male patients with chronic AF was measured using a cardiopulmonary exercise test (CPX). Within this population, we compared the exercise tolerance of patients with a normal chronotropic response (maximal HR 85%-115% that of the maximal age-predicted HR during CPX) to those whose HR response exceeded this range. Two similar comparisons were made by dividing the subject population according to (1) whether or not their HR variation index (HRVI) during CPX exceeded 10 bpm/min, and (2) whether their HR during the 6-minute walk test exceeded 110 bpm. RESULTS: Patients with an HRVI not over 10 bpm/min showed higher maximal oxygen uptake compared to patients with a higher HRVI (26.7 ± 6.1 vs 22.8 ± 4.8 mL O(2) /kg/min, P = 0.002) and a longer distance walked during CPX (705.6 ± 200.3 vs 520.9 ± 155.5 m, P<0.001). No other significant influence on exercise capacity was seen. Multivariate regression analysis revealed that both the body mass index and the HRVI during CPX were independent predictors of the maximal oxygen uptake. CONCLUSIONS: Better HRVI control on CPX was correlated with better exercise capacity in patients with chronic AF.

Solvent effects in optical spectra of ortho-aminobenzoic acid derivatives.

We investigated three amino derivatives of ortho-aminobenzoic or anthranilic acid (o-Abz): a) 2-Amino-benzamide (AbzNH2); b) 2-Amino-N-methyl-benzamide (AbzNHCH3) and c) 2-Amino-N-N'-dimethyl-bezamide (AbzNH(CH3)2), see Scheme 1. We describe the results of ab-initio calculations on the structural characteristics of the compounds and experimental studies about solvent effects in their absorption and steady-state and time-resolved emission properties. Ab-initio calculations showed higher stability for the rotameric conformation in which the oxygen of carbonyl is near to the nitrogen of ortho-amino group. The derivatives present decrease in the delocalization of pi electron, and absorption bands are blue shifted compared to the parent compound absorption, the extent of the effect increasing from to Abz-NH2 to Abz-NHCH3 Abz-NH(CH3)2. Measurements performed in several solvents have shown that the the dependence of Stokes shift of the derivatives with the orientational polarizability follows the Onsager-Lippert model for general effects of solvent. However deviation occurred in solvents with properties of Bronsted acids, or electron acceptor characteristics, so that hydrogen bonds formed with protic solvents predominates over intramolecular hydrogen bond. In most solvents the fluorescence decay of AbzNH2 and AbzNHCH3 was fitted to a single exponential with lifetimes around 7.0 ns and no correlation with polarity of the solvent was observed. The fluorescence decay of AbzN(CH3)2 showed lifetimes around 2.0 ns, consistent with low quantum yield of the compound. The spectroscopic properties of the monoamino derivative AbzNHCH3 are representative of the properties presented by Abz labelled peptides and fatty acids previously studied.

Resumenes de articulos de la literatura pediatrica: cuándo administrar oxigeno a niños en altitudes elevadas? / Abstracts of articles in the pediatric literature: when to administer oxygen to children at high altitudes?

Cada año hay más de 3 millones de muertes de niños menores de 5 años por neumonía y alrededor del 80 por ciento de ellas ocurren en países en desarrollo.

Mutagenicity and DNA adduct formation of PAH, nitro-PAH, and oxy-PAH fractions of atmospheric particulate matter from São Paulo, Brazil.

Urban particulate matter (UPM) contributes to lung cancer incidence. Here, we have studied the mutagenic activity and DNA adduct-forming ability of fractionated UPM extractable organic matter (EOM). UPM was collected with a high-volume sampler in June 2004 at two sites, one at street level adjacent to a roadway and the other inside a park within the urban area of the city of São Paulo, Brazil. UPM was extracted using dichloromethane, and the resulting EOM was separated by HPLC to obtain PAH, nitro-PAH, and oxy-PAH fractions which were tested for mutagenicity with the Salmonella strains TA98 and YG1041 with and without S9 metabolic activation. The PAH fraction from both sites showed negligible mutagenic activity in both strains. The highest mutagenic activity was found for the nitro-PAH fraction using YG1041 without metabolic activation; however, results were comparable for both sites. The nitro-PAH and oxy-PAH fractions were incubated with calf thymus DNA under reductive conditions appropriate for the activation of nitro aromatic compounds, then DNA adduct patterns and levels were determined with thin-layer chromatography (TLC) 32P-postlabeling method using two enrichment procedures-nuclease P1 digestion and butanol extraction. Reductively activated fractions from both sites produced diagonal radioactive zones (DRZ) of putative aromatic DNA adducts on thin layer plates with both enrichment procedures. No such DRZ were observed in control experiments using fractions from unexposed filters or from incubations without activating system. Total adduct levels produced by the nitro-PAH fractions were similar for both sites ranging from 30 to 45 adducts per 10(8) normal nucleotides. In contrast, the DNA binding of reductively activated oxy-PAH fractions was three times higher and the adduct pattern consisted of multiple discrete spots along the diagonal line on the thin layer plates. However, DNA adduct levels were not significantly different between the sampling sites. Both samples presented the same levels of mutagenic activity. The response in the Salmonella assay was typical of nitroaromatics. Although, more mutagenic activity was related to the nitro-PAH fraction in the Salmonella assay, the oxy-PAH fractions showed the highest DNA adduct levels. More studies are needed to elucidate the nature of the genotoxicants occurring in São Paulo atmospheric samples.

Effect of hot acid hydrolysis and hot chlorine dioxide stage on bleaching effluent biodegradability.

The hot acid hydrolysis followed by chlorine dioxide (A/D*) and hot chlorine dioxide (D*) technologies have proven very useful for bleaching of eucalyptus kraft pulp. Although the characteristics and biodegradability of effluents from conventional chlorine dioxide bleaching are well known, such information is not yet available for effluents derived from hot acid hydrolysis and hot chorine dioxide bleaching. This study discusses the characteristics and biodegradability of such effluents. Combined whole effluents from the complete sequences DEpD, D*EpD, A/D*EpD and ADEpD, and from the pre-bleaching sequences DEp, D*Ep, A/D*Ep and ADEp were characterized by quantifying their colour, AOX and organic load (BOD, COD, TOC). These effluents were also evaluated for their treatability by simulation of an activated sludge system. It was concluded that treatment in the laboratory sequencing batch reactor was efficient for removal of COD, BOD and TOC of all effluents. However, colour increased after biological treatment, with the greatest increase found for the effluent produced using the AD technology. Biological treatment was less efficient at removing AOX of effluents from the sequences with D*, A/D* and AD as the first stages, when compared to the reference D stage; there was evidence of the lower treatability of these organochlorine compounds from these sequences.

Dissolução de tecido pulpar bovino por duas composições químicas utilizadas em Endodontia / Dissolution of bovine pulp tissue by two chemical compositions used in Endodontics

O uso de composições químicas em Endodontia deve, entre outras coisas, proporcionar limpeza e desinfecção do sistema de canais radiculares. Assim, a propriedade em dissolver material orgânico é de fundamental importância para que se admita o uso de uma determinada composição química durante o preparo químico-cirúrgico ou mesmo, nas manobras de irrigação aspiração. O presente trabalho avaliou a capacidade de dissolução de polpas de dentes bovinos em clorexidina a 2 por cento, veiculada em gel de Natrosol e pela solução de hipoclorito de sódio (em diferentes concentrações e valores de pH); sob duas diferentes temperaturas. Os fragmentos do tecido pulpar foram imersos no digluconato de clorexidina a 2 por cento e hipoclorito de sódio a 5,0 por cento; 2,5 por cento; 1,0 por cento e 0,5 por cento, com valores de pH ajustados em 7,0; 9,0 e 11,0; sob duas diferentes temperaturas: 27 e 37ºC, monitorados em incubadora, para período máximo de 120 minutos. Duas amostras de fragmentos pulpares foram colocadas em água destilada, sob as duas temperaturas, servindo como controles...

Resistencia a la exposición al oxígeno de lodos anaerobios suspendidos / Oxygen exposure resistance in suspended anaerobic sludge

La tolerancia al oxígeno de una biomasa anaerobia suspendida en presencia o ausencia de un sustrato primario (sacarosa) se evaluó en términos de la recuperación de la actividad metanogénica aceticlástica especial (AME) de la biomasa anaerobia y un índice de inhibición 50 por ciento (II50) asociado a la AME. Incubada en presencia de sacarosa. La biomasa anaerobia suspendida mostró resistencia a la exposición al oxígeno; la recuperación de la AME fue >45 por ciento para [O²] iniciales <20 por ciento en el espacio gaseoso, y de 10 a 12 por ciento para [O²] iniciales >20 por ciento en el espacio gaseoso. Cuando fue incubada son fuente, la biomasa suspendida fue mucho más inhibida después de la exposición al oxígeno para [O²] iniciales >20 por ciento. El efecto inhibitorio fue descrito por un II50 elevado /28,6) en contraste con un bajo II50 (5,9) cuando se incubó en presencia de sacarosa. La tolerancia de la biomasa suspendida en este trabajo parece ser del mismo orden de la biomasa anaerobia inmovilizada (gránulos anaerobios) en condiciones de incubación en presencia de sustrato: los II50 fueron 5,9 para todos anaerobios suspendidos (sacarosa) y 5,3 y 2,4 para todos granulares incubados con acetato etanol, respectivamente. La respiración aerobia heterótrofa de los lodos anaerobio floculentos incubados con sacarosa fue cerca de 4 veces mayor que la respiración basal, y la inhibición de la AME descrita por el II50 parece seguir una relación inversa con la respiración aerobia heterótrofa. La relación inversa entre II50 y respiración aerobia heterótrofa se ajustó para datos de todos granulares en la literatura y todos floculentos de este trabajo, y sigue un modelo semi-empírico general, con un coeficiente de correlación de 0,82. Esta relación parece reforzar que uno de los mecanismos principales de protección de los consorcios anaerobios contra la inhibición por oxígeno es la respiración aerobia heterótrofa

Neumoencéfalo postraumático tratado con oxígeno normobárico en una niña / Post-traumatic pneumocephalus treated with normobaric oxygen in a girl

Introducción: El neumoencéfalo es el atrapamiento de aire dentro de la cavidad craneal; puede comportarse como una lesión ocupativa, incrementar la presión intracraneana, provocar herniación cerebral e incluso la muerte. En ocasiones el tratamiento debe ser urgente. Si las manifestaciones son menos graves, pueden resolverse utilizando oxígeno (O2) normobárico. Caso clínico. Se presenta una niña de nueve años con traumatismo craneoencefálico grave y fístula transitoria de líquido cefalorraquídeo (LCR); desarrolló estado de estupor, síndrome de hipertensión intracraneana y meningitis secundaría a la fístula de LCR. La tomografía axial computada (TAC) mostró neumoencéfalo bifrontal de predominio izquierdo. Se trató antibióticos por 15 días y O2 nomobárico al 40 por ciento durante siete días. El control tomográfico mostró resolución del neumoencéfalo. Conclusión: El uso de O2 normobárico en concentraciones del 40 al 100 por ciento es útil en el tratamiento del neumoencéfalo de causa diversa. Es una modalidad de tratamiento de bajo costo, no invasiva y con excelentes resultados en pacientes seleccionados

El spin del electrón como soporte de la energía homeopática / The spin of the electron as suport of energy homeopathic

El paramagnetismo del oxígeno puede dar lugar a un enlace de intercambio entre los oxígenos de dos moléculas de agua. Este enlace se formaría en una pequeña cantidad de moléculas y podría desplazarse de una molécula a otra, inclusive formando la misma unión entre los oxígenos semiacetálicos de los monos y disacáridos; en el organismo podría reubicarse en la deoxiribosa del ADN y en la ribosa del ARN. La sucusión y la trituración pueden modular en forma permanente el spin de los electrones que forman este enlace con frecuencias que reflejan las características del medicamento. Cuando el enlace de intercambio consigue ubicarse en el ADN, esta modulación del spin puede activar información allí dormida, lo que explicaría la profunda y amplia acción curativa del remedio homeopático (AU)

El spin del electrón como soporte de la energía homeopática / The spin of the electron as suport of energy homeopathic

El paramagnetismo del oxígeno puede dar lugar a un enlace de intercambio entre los oxígenos de dos moléculas de agua. Este enlace se formaría en una pequeña cantidad de moléculas y podría desplazarse de una molécula a otra, inclusive formando la misma unión entre los oxígenos semiacetálicos de los monos y disacáridos; en el organismo podría reubicarse en la deoxiribosa del ADN y en la ribosa del ARN. La sucusión y la trituración pueden modular en forma permanente el spin de los electrones que forman este enlace con frecuencias que reflejan las características del medicamento. Cuando el enlace de intercambio consigue ubicarse en el ADN, esta modulación del spin puede activar información allí dormida, lo que explicaría la profunda y amplia acción curativa del remedio homeopático