HERITABILITY OF AEROBIC POWER OF INDIVIDUALS IN NORTHEAST BRAZIL

The objective of this study was to evaluate the genetic and environmental contribution to variation in aerobic power in monozygotic (MZ) and dizygotic (DZ) twins. The sample consisted of 20 MZ individuals (12 females and 8 males) and 16 DZ individuals (12 females and 4 males), aged from 8 to 26 years, residents in Natal, Rio Grande do Norte. The twins were assessed by a multistage fitness test. The rate of heritability found for aerobic power was 77%. Based on the results, the estimated heritability was largely responsible for the differences in aerobic power. This implies that such measures are under strong genetic influence.     

Nailfold videocapillaroscopy micro-haemorrhage and giant capillary counting as an accurate approach for a steady state definition of disease activity in systemic sclerosis

Introduction

Nailfold videocapillaroscopy (NVC) in systemic sclerosis (SSc) is a procedure commonly used for patient classification and subsetting, but not to define disease activity (DA). This study aimed to evaluate whether the number of micro-haemorrhages (MHE), micro-thrombosis (MT), giant capillaries (GC), and normal/dilated capillaries (Cs) in NVC could predict DA in SSc.

Methods

Eight-finger NVC was performed in 107 patients with SSc, and the total number of MHE/MT, GC, and the mean number of Cs were counted and defined as number of micro-haemorrhages (NEMO), GC and Cs scores, respectively. The European Scleroderma Study Group (ESSG) index constituted the gold standard for DA assessment, and scores ≥3.5 and =3 were considered indicative of high and moderate activity, respectively.

Results

NEMO and GC scores were positively correlated with ESSG index (R = 0.65, P <0.0001, and R = 0.47, P <0.0001, respectively), whilst Cs score showed a negative correlation with that DA index (R = −0.30, P <0.001). The area under the curve (AUC) of receiver operating characteristic plots, obtained by NEMO score sensitivity and specificity values in classifying patients with ESSG index ≥3.5, was significantly higher than the corresponding AUC derived from either GC or Cs scores (P <0.03 and P <0.0006, respectively). A modified score, defined by the presence of a given number of MHE/MT and GC, had a good performance in classifying active patients (ESSG index ≥3, sensitivity 95.1%, specificity 84.8%, accuracy 88.7%).

Conclusions

MHE/MT and GC appear to be good indicators of DA in SSc, and enhances the role of NVC as an easy technique to identify active patients.     

Knockdown of hepatocyte aquaporin-8 by RNA interference induces defective bile canalicular water transport

Aquaporin-8 (AQP8) water channels, which are expressed in rat hepatocyte bile canalicular membranes, are involved in water transport during bile formation. Nevertheless, there is no conclusive evidence that AQP8 mediates water secretion into the bile canaliculus. In this study, we directly evaluated whether AQP8 gene silencing by RNA interference inhibits canalicular water secretion in the human hepatocyte-derived cell line, HepG2. By RT-PCR and immunoblotting we found that HepG2 cells express AQP8 and by confocal immunofluorescence microscopy that it is localized intracellularly and on the canalicular membrane, as described in rat hepatocytes. We also verified the expression of AQP8 in normal human liver. Forty-eight hours after transfection of HepG2 cells with RNA duplexes targeting two different regions of human AQP8 molecule, the levels of AQP8 protein specifically decreased by 60-70%. We found that AQP8 knockdown cells showed a significant decline in the canalicular volume of approximately 70% (P < 0.01), suggesting an impairment in the basal (nonstimulated) canalicular water movement. We also found that the decreased AQP8 expression inhibited the canalicular water transport in response either to an inward osmotic gradient (-65%, P < 0.05) or to the bile secretory agonist dibutyryl cAMP (-80%, P < 0.05). Our data suggest that AQP8 plays a major role in water transport across canalicular membrane of HepG2 cells and support the notion that defective expression of AQP8 causes bile secretory dysfunction in human hepatocytes.     

Potassium transmembrane fluxes in anoxic hepatocytes from goldfish (Carassius auratus L.)

Despite the fact that anoxic goldfish hepatocytes can maintain the transmembrane gradients of Na(+), H(+) and Ca(2+), cyanide (CN) intoxication leads to a rapid breakdown of K(+) homeostasis. In this study, [(86)Rb(+)] K(+) fluxes across the plasma membrane of goldfish hepatocytes were studied in order to identify the possible causes of this imbalance. Four minutes of cyanide incubation induced an acute and stable 61% decrease of K(+) influx (mostly driven by Na,K-ATPase activity), whereas K(+) efflux increased by 24.3%, this imbalance yielding a net K(+) efflux of 0.279+/-0.024 nmol 10(-6) cells(-1) min(-1). This uncoupling was not observed when glycolytic ATP production was inhibited with iodoacetic acid. Although the CN-induced decrease of K(+) influx was fully reversible upon washout of the inhibitor, it could not be prevented by any of the following treatments: (1) addition of 2% bovine serum albumin, which binds extracellular fatty acids known to activate specific K(+) channels; (2) addition of ascorbate, which acts as a radical scavenger; (3) inclusion of 5 mM glucose as an extracellular carbon source; and (4) removal of medium oxygen (obtained by nitrogen bubbling). Regarding the elevation of K(+) efflux in the presence of CN, neither ATP-dependent K(+) channels nor the KCl cotransporter appeared to be activated, whereas BaCl(2), an inhibitor of voltage-gated K(+) channels, decreased K(+) efflux of CN-intoxicated cells to control levels. In summary, these results indicate that, in goldfish hepatocytes, the CN-induced K(+) imbalance results from acute Na,K-ATPase inhibition together with the activation of voltage-dependent K(+) channels, the latter probably resulting from transient membrane depolarization.     

Outcome of Tuberculosis Treatment in Patients with Diabetes Mellitus Treated in the Revised National Tuberculosis Control Programme in Malappuram District,Kerala, India

Settings

Kerala State, India has reported the greatest dual burden of Tuberculosis (TB) and Diabetes Mellitus (DM). Malappuram district in Kerala has monitored and recorded DM status and its control from 2010 under Revised National Tuberculosis Control Program (RNTCP).

Objectives

To assess, under programme conditions, comprehensiveness of recording DM status among TB cases and the TB treatment outcomes among DM patients (disaggregated by glycemic control) and compare with-non DM patients.

Design

This retrospective record review included 3,116TB patients from April 2010 to September 2011.DM was defined as per international guidelines and TB treatment outcomes were categorized as favourable(cured and treatment completed) and unfavourable(death, default, failure and transfer out). Relative Risk (RR) and 95% confidence intervals(CI) were calculated to assess the risk of unfavourable outcomes.

Results

DM status was recorded in 90% of TB cases and 667 (24%) had DM. 17% of DM patients and 23% of patients with unknown DM status had unfavourable outcomes but this difference was not statistically significant. Unadjusted RR for poor glycemic control or unknown control status for unfavourable outcome were (2.00; 95% CI 0.97–4.13) and (2.14; 95% CI 1.11–4.13).

Conclusion

This study could not confirm an adverse association between DM or its control during treatment and the course of response to TB treatment.DM screening in TB cases and recording of DM care needs to be improved to enable more conclusive evidence.     

Kinetics of extracellular ATP in mastoparan 7-activated human erythrocytes

Background

The peptide mastoparan 7 (MST7) stimulated ATP release in human erythrocytes. We explored intra- and extracellular processes governing the time-dependent accumulation of extracellular ATP (i.e., ATPe kinetics).

Methods

Human erythrocytes were treated with MST7 in the presence or absence of two blockers of pannexin 1. ATPe concentration was monitored by luciferin–luciferase based real-time luminometry.

Results

Exposure of human erythrocytes to MST7 led to an acute increase in [ATPe], followed by a slower increase phase. ATPe kinetics reflected a strong activation of ATP efflux and a low rate of ATPe hydrolysis by ectoATPase activity. Enhancement of [ATPe] by MST7 required adhesion of erythrocytes to poly-D-lysin-coated coverslips, and correlated with a 31% increase of cAMP and 10% cell swelling. However, when MST7 was dissolved in a hyperosmotic medium to block cell swelling, ATPe accumulation was inhibited by 49%.Erythrocytes pre-exposure to 10 μM of either carbenoxolone or probenecid, two blockers of pannexin 1, exhibited a partial reduction of ATP efflux.Erythrocytes from pannexin 1 knockout mice exhibited similar ATPe kinetics as those of wild type mice erythrocytes exposed to pannexin 1 blockers.

Conclusions

MST7 induced release of ATP required either cell adhesion or strong activation of cAMP synthesis. Part of this release required cell swelling. Kinetic analysis and a data driven model suggested that ATP efflux is mediated by two ATP conduits displaying different kinetics, with one conduit being fully blocked by pannexin 1 blockers.

General significance

Kinetic analysis of extracellular ATP accumulation from human erythrocytes and potential effects on microcirculation.     

An integrated Bayesian analysis of LOH and copy number data

Background  

Cancer and other disorders are due to genomic lesions. SNP-microarrays are able to measure simultaneously both genotype and copy number (CN) at several Single Nucleotide Polymorphisms (SNPs) along the genome. CN is defined as the number of DNA copies, and the normal is two, since we have two copies of each chromosome. The genotype of a SNP is the status given by the nucleotides (alleles) which are present on the two copies of DNA. It is defined homozygous or heterozygous if the two alleles are the same or if they differ, respectively. Loss of heterozygosity (LOH) is the loss of the heterozygous status due to genomic events.     

The kinome of Phytophthora infestans reveals oomycete-specific innovations and links to other taxonomic groups

Background

Paracoccidioides brasiliensis (Eukaryota, Fungi, Ascomycota) is a thermodimorphic fungus, the etiological agent of paracoccidioidomycosis, the most important systemic mycoses in Latin America. Three isolates corresponding to distinct phylogenetic lineages of the Paracoccidioides species complex had their genomes sequenced. In this study the identification and characterization of class II transposable elements in the genomes of these fungi was carried out.

Results

A genomic survey for DNA transposons in the sequence assemblies of Paracoccidioides, a genus recently proposed to encompass species P. brasiliensis (harboring phylogenetic lineages S1, PS2, PS3) and P. lutzii (Pb01-like isolates), has been completed. Eight new Tc1/mariner families, referred to as Trem (Tr ansposable e lement m ariner), labeled A through H were identified. Elements from each family have 65-80% sequence similarity with other Tc1/mariner elements. They are flanked by 2-bp TA target site duplications and different termini. Encoded DDD-transposases, some of which have complete ORFs, indicated that they could be functionally active. The distribution of Trem elements varied between the genomic sequences characterized as belonging to P. brasiliensis (S1 and PS2) and P. lutzii. TremC and H elements would have been present in a hypothetical ancestor common to P. brasiliensis and P. lutzii, while TremA, B and F elements were either acquired by P. brasiliensis or lost by P. lutzii after speciation. Although TremD and TremE share about 70% similarity, they are specific to P. brasiliensis and P. lutzii, respectively. This suggests that these elements could either have been present in a hypothetical common ancestor and have evolved divergently after the split between P. brasiliensis and P. Lutzii, or have been independently acquired by horizontal transfer.

Conclusions

New families of Tc1/mariner DNA transposons in the genomic assemblies of the Paracoccidioides species complex are described. Families were distinguished based on significant BLAST identities between transposases and/or TIRs. The expansion of Trem in a putative ancestor common to the species P. brasiliensis and P. lutzii would have given origin to TremC and TremH, while other elements could have been acquired or lost after speciation had occurred. The results may contribute to our understanding of the organization and architecture of genomes in the genus Paracoccidioides.