Electrical impedance tomography in acute respiratory distress syndrome.

Acute respiratory distress syndrome (ARDS) is a clinical entity that acutely affects the lung parenchyma, and is characterized by diffuse alveolar damage and increased pulmonary vascular permeability. Currently, computed tomography (CT) is commonly used for classifying and prognosticating ARDS. However, performing this examination in critically ill patients is complex, due to the need to transfer these patients to the CT room. Fortunately, new technologies have been developed that allow the monitoring of patients at the bedside. Electrical impedance tomography (EIT) is a monitoring tool that allows one to evaluate at the bedside the distribution of pulmonary ventilation continuously, in real time, and which has proven to be useful in optimizing mechanical ventilation parameters in critically ill patients. Several clinical applications of EIT have been developed during the last years and the technique has been generating increasing interest among researchers. However, among clinicians, there is still a lack of knowledge regarding the technical principles of EIT and potential applications in ARDS patients. The aim of this review is to present the characteristics, technical concepts, and clinical applications of EIT, which may allow better monitoring of lung function during ARDS.

Adsorption of flexible polymer chains on a surface: Effects of different solvent conditions.

Polymer chains undergoing a continuous adsorption-desorption transition are studied through extensive computer simulations. A three-dimensional self-avoiding walk lattice model of a polymer chain grafted onto a surface has been treated for different solvent conditions. We have used an advanced contact-density chain-growth algorithm, in which the density of contacts can be directly obtained. From this quantity, the order parameter and its fourth-order Binder cumulant are computed, as well as the corresponding critical exponents and the adsorption-desorption transition temperature. As the number of configurations with a given number of surface contacts and monomer-monomer contacts is independent of the temperature and solvent conditions, it can be easily applied to get results for different solvent parameter values without the need of any extra simulations. In analogy to continuous magnetic phase transitions, finite-size-scaling methods have been employed. Quite good results for the critical properties and phase diagram of very long single polymer chains have been obtained by properly taking into account the effects of corrections to scaling. The study covers all solvent effects, going from the limit of super-self-avoiding walks, characterized by effective monomer-monomer repulsion, to poor solvent conditions that enable the formation of compact polymer structures.

Preeclampsia: mediadores moleculares del daño placentario / Preeclampsia: molecular mediators of placental damage

La preeclampsia se constituye como una de las complicaciones más serias del embarazo y una causa importante de mortalidad materna y perinatal. Pese a ser una de las patologías del embarazo más estudiadas, muchas dudas e incertidumbre rondan aún acerca de su mecanismo fisiopatológico. En esta revisión se intenta hacer un análisis sobre las nuevas teorías acerca de la fisiopatología de la preeclampsia, dando énfasis en las distintas moléculas que transfieren el daño placentario hacia el territorio sistémico.

Preeclampsia is one of the most serious gestational disease which causes maternal and perinatal mortality. In spite of being one of the most studied pathologies of the pregnancy there are many concerns around its physiopathology. In this review we attempt to analyze the new preeclampsia physiopathology theories, giving emphasis in the different molecules that transfer the placental damage towards the systemic territory.

[Lead poisoning: clinical picture, diagnosis and related environmental factors]. / Intoxicación por plomo: clínica, diagnóstico y factores ambientales condicionantes.

BACKGROUND: The predisposing environmental factors and clinical picture of lead poisoning, are not well known. AIM: To describe the clinical picture, diagnosis and treatment of lead poisoning in individuals under industry exposure. SUBJECTS AND METHODS: Twenty of 38 workers of a printing press were studied. Their medical and labor histories were recorded. Lead in air in the working area and the dose received by the workers was measured. RESULTS: The environmental lead in the linotype room was 25% over the accepted values. Twelve of the 20 workers were poisoned and three were highly exposed. Poisoned workers were working in areas with high environmental lead concentrations, were in direct contact with the metal, had plasma lead concentrations over 70 micrograms/dl and an average exposure time of over 17 years. Their clinical picture was not specific and related to plasma and environmental lead concentrations, length of exposure and type of contact. CONCLUSIONS: Lead poisoning must be suspected among workers exposed to high environmental concentrations and its treatment consists in withdrawing poisoned subjects from polluted areas.

Intoxicación por plomo: clínica, diagnóstico y factores ambientales condicionantes / Lead poisoning: clinics, diagnosis and environmental related factors

The environmental lead in the linotype room was 25 percent over the accepted values. Twelve of the 20 workers were poisoned and 3 were highly exposed. Poisoned workers were working in areas with high environmental lead concentrations, were in direct contact with the metal, had plasma lead concentrations over 70 ug/dl and an average exposure time over 17 years. Their clinical picture was not specific and related to plasma and environmental lead concentrations, length of exposure and type of contact. Lead poisoning must be suspected among workers exposed to high environmental concentrations and its treatment consists in withdrawing poisoned subjects from polluted areas.

Rapid genetic characterization of HIV type 1 strains from four World Health Organization-sponsored vaccine evaluation sites using a heteroduplex mobility assay. WHO Network for HIV Isolation and Characterization.

To assist in the preparation for the testing of vaccines against human immunodeficiency virus (HIV) we, as part of the World Health Organization Network for HIV Isolation and Characterization (WHO-NHIC), evaluated the genotypic variation of HIV-1 in cohorts from Brazil, Rwanda, Thailand, and Uganda. Here we report the results from a pilot study of 65 HIV-1-infected individuals. In all cases in which viral envelope gene fragments could be amplified by polymerase chain reaction, subtypes could be assigned using a heteroduplex mobility assay (HMA)1 by comparison with HIV-1 strains representing six HIV-1 envelope subtypes. All subtype classifications matched those found by envelope gene sequencing. Phylogenetic relationships were further clarified by heteroduplex formation between samples within each subtype. A relatively homogeneous subtype E virus population predominated over subtype B viruses in the sample set from Thailand. Viruses from the other countries were also limited to one or two subtypes but were more divergent within each subtype. All samples from Rwanda (13/13) and some from Uganda (3/16) were of subtype A; all Brazilian samples were of subtype B, except for one belonging to subtype C; most samples from Uganda (13/16) clustered with the subtype D. Analysis by HMA is therefore applicable for screening of HIV-1 genotypes in countries under consideration for large-scale vaccine trials. It should be generally useful when samples containing at least one variable genetic locus need to be rapidly classified by genotype and/or analyzed for epidemiological clustering.