Clinical utility of standard base excess in the diagnosis and interpretation of metabolic acidosis in critically ill patients

The aims of this study were to determine whether standard base excess (SBE) is a useful diagnostic tool for metabolic acidosis, whether metabolic acidosis is clinically relevant in daily evaluation of critically ill patients, and to identify the most robust acid-base determinants of SBE. Thirty-one critically ill patients were enrolled. Arterial blood samples were drawn at admission and 24 h later. SBE, as calculated by Van Slyke's (SBE VS) or Wooten's (SBE W) equations, accurately diagnosed metabolic acidosis (AUC = 0.867, 95%CI = 0.690-1.043 and AUC = 0.817, 95%CI = 0.634-0.999, respectively). SBE VS was weakly correlated with total SOFA (r = -0.454, P < 0.001) and was similar to SBE W (r = -0.482, P < 0.001). All acid-base variables were categorized as SBE VS <-2 mEq/L or SBE VS <-5 mEq/L. SBE VS <-2 mEq/L was better able to identify strong ion gap acidosis than SBE VS <-5 mEq/L; there were no significant differences regarding other variables. To demonstrate unmeasured anions, anion gap (AG) corrected for albumin (AG A) was superior to AG corrected for albumin and phosphate (AG A+P) when strong ion gap was used as the standard method. Mathematical modeling showed that albumin level, apparent strong ion difference, AG A, and lactate concentration explained SBE VS variations with an R² = 0.954. SBE VS with a cut-off value of <-2 mEq/L was the best tool to diagnose clinically relevant metabolic acidosis. To analyze the components of SBE VS shifts at the bedside, AG A, apparent strong ion difference, albumin level, and lactate concentration are easily measurable variables that best represent the partitioning of acid-base derangements.

Subjective versus objective stress in noncritically ill hospitalized and outpatient adult men

A cross-sectional study of 120 subjects was performed with the purpose of evaluating stress hormones and emotional stress (anxiety) in outpatient and hospitalized subjects. The aims were to determine the degree of objective stress, as well as to correlate this finding with subjective findings, estimated using Beck's Anxiety Inventory.. METHOD: Three populations were investigated, namely outpatient clinical cases (Group I, n = 30), hospitalized clinical individuals (Group II, n = 30), and hospitalized surgical candidates (Group III, n = 30). Controls (Group IV, n = 30) were healthy volunteers who were health-care professionals and students. To avoid hormone interactions, only men were enrolled in all groups. All hospitalized subjects were tested on admission and before therapeutic interventions. Fasting epinephrine, norepinephrine, and cortisol were measured in the morning, and Beck's Anxiety Inventory was adminstered by a trained psychologist. RESULTS: The 3 patient groups displayed higher anxiety levels than the controls. Hormone concentrations did not present remarkable changes and did not correlate with subjective stress (anxiety). CONCLUSIONS: 1) Subjective disorders (as determined with Beck's Anxiety Inventory ) were a common finding in both outpatient and hospitalized populations, without differences between the various groups; 2) Objective stress (as determined by elevated hormone levels) was more difficult to confirm-findings rarely exceeded the reference range; 3) Correlation between the two variables could not be demonstrated; 4) Further studies are necessary to define stress quantification and interpretation in patient populations, especially in relationship with nutritional diagnosis and dietetic prescription.

Susceptibility of Colombian Plasmodium falciparum isolates to 4-aminoquinolines and the definition of amodiaquine resistance in vitro

There are wide variations in the threshold used to define in vitro resistance of Plasmodium falciparum to amodiaquine (AQ), probably due to differences in methodology and interpretation. In vitro susceptibility data of Colombian P. falciparum strains to AQ and N-desethylamodiaquine is used to illustrate the need to standardized methodologies and compare inhibitory concentrations, instead of resistant/susceptible phenotypes, when studying the mechanisms of resistance to AQ and monitoring drug susceptibility trends in the field.

Thermal behaviour study of solid state compounds of manganese (II), zinc (II) and lead (II) with cinnamic acid

Compounds of cinnamic acid with manganese, zinc and lead have been prepared in aqueous solution. Thermogravimetry, derivative thermogravimetry (TG, DTG), differential scanning calorimetry (DSC), X-ray diffraction and complexometry have been used in the characterization as well as in the study of the thermal stability and interpretation concerning the thermal decomposition.

Effects of Cinnamon extract on biochemical enzymes, TNF-α and NF-κB gene expression levels in liver of broiler chickens inoculated with Escherichia coli

Abstract: Infection with Escherichia coli (E. coli) is a common disease in poultry industry. The use of antibiotics to treat diseases is facing serious criticism and concerns. The medicinal plants may be effective alternatives because of their multiplex activities. The aim of this study was to investigate the effects of cinnamon extract on the levels of liver enzymes, tumor necrosis factor-alpha (TNF-α) and nuclear factor-kappa B (NF-κB) gene expressions in liver of broiler chickens infected with E. coli. Ninety Ross-308 broilers were divided into healthy or E. coli-infected groups, receiving normal or cinnamon extract (in concentrations of 100 or 200mg/kg of food) supplemented diets. E. coli suspension (108cfu) was injected subcutaneously after 12 days cinnamon administration. Seventy-two hours after E. coli injection, the blood samples were taken for biochemical analysis of liver enzymes in serum (spectrophotometrically), and liver tissue samples were obtained for detection of gene expression of inflammatory markers TNF-α and NF-κB, using real-time PCR. Infection with E. coli significantly increased the levels of TNF-α and NF-κB gene expressions as well as some liver enzymes including creatine-kinase (CK), lactate-dehydrogenase (LDH), alanine-transferase (ALT) and aspartate-transferase (AST) as compared with control group (P<0.05). Pre-administration of cinnamon extract in broilers diet (in both concentrations) significantly reduced the tissue levels of TNF-α and NF-κB gene expressions and enzymes CK and ALT in serum of broiler chickens inoculated with E. coli in comparison with E. coli group (P<0.05 and P<0.01). The levels of LDH and AST were significantly decreased only by 200mg/kg cinnamon extract in infected broilers. The level of alkaline-phosphatase (ALP) was not affected in any groups. Pre-administration of cinnamon extract in diets of broiler chickens inoculated with E. coli could significantly reduce the gene expression levels of pro-inflammatory mediators and liver enzymes activities, thereby protecting the liver against this pathologic condition.

Effect of race, genetic population structure, and genetic models in two-locus association studies: clustering of functional renin-angiotensin system gene variants in hypertension association studies

Previous genetic association studies have overlooked the potential for biased results when analyzing different population structures in ethnically diverse populations. The purpose of the present study was to quantify this bias in two-locus association studies conducted on an admixtured urban population. We studied the genetic structure distribution of angiotensin-converting enzyme insertion/deletion (ACE I/D) and angiotensinogen methionine/threonine (M/T) polymorphisms in 382 subjects from three subgroups in a highly admixtured urban population. Group I included 150 white subjects; group II, 142 mulatto subjects, and group III, 90 black subjects. We conducted sample size simulation studies using these data in different genetic models of gene action and interaction and used genetic distance calculation algorithms to help determine the population structure for the studied loci. Our results showed a statistically different population structure distribution of both ACE I/D (P = 0.02, OR = 1.56, 95% CI = 1.05-2.33 for the D allele, white versus black subgroup) and angiotensinogen M/T polymorphism (P = 0.007, OR = 1.71, 95% CI = 1.14-2.58 for the T allele, white versus black subgroup). Different sample sizes are predicted to be determinant of the power to detect a given genotypic association with a particular phenotype when conducting two-locus association studies in admixtured populations. In addition, the postulated genetic model is also a major determinant of the power to detect any association in a given sample size. The present simulation study helped to demonstrate the complex interrelation among ethnicity, power of the association, and the postulated genetic model of action of a particular allele in the context of clustering studies. This information is essential for the correct planning and interpretation of future association studies conducted on this population.

Uncertainties regarding dengue modeling in Rio de Janeiro, Brazil

Dengue fever is currently the most important arthropod-borne viral disease in Brazil. Mathematical modeling of disease dynamics is a very useful tool for the evaluation of control measures. To be used in decision-making, however, a mathematical model must be carefully parameterized and validated with epidemiological and entomological data. In this work, we developed a simple dengue model to answer three questions: (i) which parameters are worth pursuing in the field in order to develop a dengue transmission model for Brazilian cities; (ii) how vector density spatial heterogeneity influences control efforts; (iii) with a degree of uncertainty, what is the invasion potential of dengue virus type 4 (DEN-4) in Rio de Janeiro city. Our model consists of an expression for the basic reproductive number (R0) that incorporates vector density spatial heterogeneity. To deal with the uncertainty regarding parameter values, we parameterized the model using a priori probability density functions covering a range of plausible values for each parameter. Using the Latin Hypercube Sampling procedure, values for the parameters were generated. We conclude that, even in the presence of vector spatial heterogeneity, the two most important entomological parameters to be estimated in the field are the mortality rate and the extrinsic incubation period. The spatial heterogeneity of the vector population increases the risk of epidemics and makes the control strategies more complex. At last, we conclude that Rio de Janeiro is at risk of a DEN-4 invasion. Finally, we stress the point that epidemiologists, mathematicians, and entomologists need to interact more to find better approaches to the measuring and interpretation of the transmission dynamics of arthropod-borne diseases.

Challenges of phylogenetic analyses of aDNA sequences

One of the crucial steps of authentication of aDNA sequences is phylogenetic consistency. Amplified sequences should fit into the phylogenetic framework of their supposed origin. An inherent property of aDNA sequences however, is their short sequence length. Additionally, genes for aDNA studies are often chosen by their preservation potential rather than by phylogenetically informative content. This poses potential challenges regarding their analyses, and might result in an inaccurate reflection of the supposed phylogenetic history of the sequence or organism under study. In this paper some fundamental problems of phylogenetic analysis and interpretation of aDNA datasets are discussed. Suggestions for character sampling and treatment of missing data are made. The publication is the result of a talk from the 1st PAMINSA Meeting in Rio de Janeiro, July 2005.

Isozymic variability in a Brazilian collection of annatto (Bixa orellana L.)

The objectives of this work were to optimize the isozyme electrophoresis technique for Bixa orellana, and use isozyme markers for a preliminary survey on the genetic variability in Brazilian annatto germplasm accessions. Collection consisted of seed samples from sixty open pollinated trees, representing two Northern and four Southern geographic provenances. The extraction, electrophoresis, and interpretation of annatto isozymes are described. Three out of the twenty-one identified isozyme loci were polymorphic in the collection. The percentage of polymorphic loci (P = 21.05) and the expected heterozygosity in annatto (H T = 0.064) were low, compared to other tropical woody species. A UPGMA phenogram, constructed with Nei's genetic distances, clearly separated the germplasm provenant from North and Central Brazil. Variability was significantly higher among the accessions from Maranhão. A sharp genetic differentiation was detected between accessions from Maranhão and Pará States, despite their geographical proximity. The distinctive isozyme polymorphism, observed in the accessions from Maranhão, together with reports on local morphological heterogeneity in annatto fruit shape, color, and pubescence, calls for more detailed genetic and taxonomic investigation.

Classificação periódica: um exemplo didático para ensinar análise de componentes principais

A dataset of chemical properties of the elements is used herein to introduce principal components analysis (PCA). The focus in this article is to verify the classification of the elements within the periodic table. The reclassification of the semimetals as metals or nonmetals emerges naturally from PCA and agrees with the current SBQ/IUPAC periodic table. Dataset construction, basic preprocessing, loading and score plots, and interpretation have been emphasized. This activity can be carried out even when students with distinct levels of formation are together in the same learning environment.

The literary arts in Hume's science of the fancy

Philosophers have long disagreed about whether poetry, drama, and other literary arts are important to philosophy; and among those who believe that they are important, explanations of that importance have differed greatly. This paper aims to explain and illustrate some of the reasons why Hume found literature to be an important topic for philosophy and philosophers. Philosophy, he holds, can help to explain general and specific literary phenomena, to ground the science of criticism, and to suggest and justify ";principles of art,"; while at the same time literature can provide valuable ";experiments"; for philosophical theorizing and provide it with a model for the science of morals and (in some ways) for philosophy itself. Moreover, the literary arts can not only help one to write better philosophy, in Hume's view; they can also help one to write philosophy better.

Use of penetrometers in agriculture: a review

Soil physical quality can be easily and quickly evaluated by using simple equipment to identify levels of soil compaction. Hence, it is necessary to know the variables responsible for changes in the soil penetration resistance (SPR). The aim of this review is to identify the main factors related to the various equipment used for assessing SPR as a soil physical quality indicator in agriculture. This literature review describes the different types of equipment used and its relationship with SPR. A wide range of procedures, devices, and equipments are available. Much of variability in SPR results is related to the equipment model, cone angle and diameter, and penetration rate. Usually, restrictions to root growth are correlated with SPR values above 2-3 MPa. However, comparisons of SPR values obtained under different soil moisture regimes in the same soil type have provided conflicting results of difficult interpretation. In order to minimize these problems, there is a need for standardization of measurement procedures and interpretation, and/or correction of SPR values according to a soil water content of reference.