Actinobacillus actinomycetemcomitans serotype-specific genotypes and periodontal status in Brazilian subjects

Periodontitis is associated with members of the oral microbiota, such as Actinobacillus actinomycetemcomitans. To our knowledge, this is the first study to evaluate, by PCR, the occurrence of the six known bacterium serotypes that included subjects with and without periodontitis. Our group comprised 49 Brazilian subjects. We studied 146 bacterial isolates from 23 patients with aggressive or chronic periodontitis and 26 subgingival specimens from subjects with or without periodontitis, all originating in our collection. Serotypes b and c were observed in similar frequencies, and no subject harboured d, e, or f serotype strains. Around 78% subjects had single-serotype infection. Mixed infection was seen only in aggressive periodontitis patients. An association between serotype b and healthy periodontium and between serotype c and chronic periodontitis was observed. Our results diverge from those previously reported, which may be explained by specific distribution patterns in distinct populations. The association of different serotypes with the same periodontal status or conversely of a serotype with different periodontal conditions indicates that organism serotyping should not be used as a sole reliable marker for predicting the outcome of the infection. Evaluation of factors involved in human oral cavity colonization by subsets of A. actinomycetemcomitans is essential for elucidating organism-host-environment relationships.     

Extremophilic Acinetobacter Strains from High-Altitude Lakes in Argentinean Puna: Remarkable UV-B Resistance and Efficient DNA Damage Repair

High-Altitude Andean Lakes (HAAL) of the South American Andes are almost unexplored ecosystems of shallow lakes. The HAAL are recognized by a remarkably high UV exposure, strong changes in temperature and salinity, and a high content of toxic elements, especially arsenic. Being exposed to remarkably extreme conditions, they have been classified as model systems for the study of life on other planets. Particularly, Acinetobacter strains isolated from the HAAL were studied for their survival competence under strong UV-B irradiation. Clinical isolates, Acinetobacter baumannii and Acinetobacter johnsonii, served as reference material. Whereas the reference strains rapidly lost viability under UV-B irradiation, most HAAL-derived strains readily survived this exposure and showed less change in cell number after the treatment. Controls for DNA repair activity, comparing dark repair (DR) or photo repair (PR), gave evidence for the involvement of photolyases in the DNA repair. Comparative measurements by HPLC-mass spectrometry detected the number of photoproducts: bipyrimidine dimers under both PR and DR treatments were more efficiently repaired in the HAAL strains (up to 85?% PR and 38?% DR) than in the controls (31?% PR and zero DR ability). Analysis of cosmid-cloned total genomic DNA from the most effective DNA-photorepair strain (Ver3) yielded a gene (HQ443199) encoding a protein with clear photolyase signatures belonging to class I CPD-photolyases. Despite the relatively low sequence similarity of 41?% between the enzymes from Ver3 and from E. coli (PDB 1DNPA), a model-building approach revealed a high structural homology to the CPD-photolyase of E. coli.     

P2X<Subscript>7</Subscript> receptor and klotho expressions in diabetic nephropathy progression

Diabetes mellitus is characterized by increased levels of reactive oxygen species (ROS), leading to high levels of adenosine triphosphate (ATP) and the activation of purinergic receptors (P2X₇), which results in cell death. Klotho was recently described as a modulator of oxidative stress and as having anti-apoptotic properties, among others. However, the roles of P2X₇ and klotho in the progression of diabetic nephropathy are still unclear. In this context, the aim of the present study was to characterize P2X₇ and klotho in several stages of diabetes in rats. Diabetes was induced in Wistar rats by streptozotocin, while the control group rats received the drug vehicle. From the 1st to 8th weeks after the diabetes induction, the animals were placed in metabolic cages on the 1st day of each week for 24 h to analyze metabolic parameters and for the urine collection. Then, blood samples and the kidneys were collected for biochemical analysis, including Western blotting and qPCR for P2X₇ and klotho. Diabetic rats presented a progressive loss of renal function, with reduced nitric oxide and increased lipid peroxidation. The P2X₇ and klotho expressions were similar up to the 4th week; then, P2X₇ expression increased in diabetes mellitus (DM), but klotho expression presented an opposite behavior, until the 8th week. Our data show an inverse correlation between P2X₇ and klotho expressions through the development of DM, which suggests that the management of these molecules could be useful for controlling the progression of this disease and diabetic nephropathy.     

Lower Inter-Partum Interval and Unhealthy Life-Style Factors Are Inversely Associated with n-3 Essential Fatty Acids Changes during Pregnancy: A Prospective Cohort with Brazilian Women

Objective

To analyze serum fatty acids concentrations during healthy pregnancy and evaluate whether socioeconomic, demographic, obstetric, nutritional, anthropometric and lifestyle factors are associated with their longitudinal changes.

Study design

A prospective cohort of 225 pregnant women was followed in the 5^th–13^th, 20^th–26^th and 30^th–36^th weeks of gestation. Serum samples were collected in each trimester of pregnancy and analyzed to determine the fatty acids composition using a high-throughput robotic direct methylation method coupled with fast gas-liquid chromatography. The independent variables comprised the subjects’ socioeconomic and demographic status, obstetric history, early pregnancy body mass index (BMI), dietary and lifestyle parameters. Analyses were performed using linear mixed-effects models.

Results

The overall absolute concentrations of fatty acids increased from the 1^st to the 2^nd trimester and slightly increased from the 2^nd to the 3^rd trimester. Early pregnancy BMI, inter-partum interval and weekly fish intake were the factors associated with changes in eicosapentaenoic + docosahexaenoic acids (EPA+DHA) and total n-3 polyunsaturated fatty acids (PUFAs). Early pregnancy BMI, age and monthly per-capita income were inversely associated with the changes in the n-6/n-3 ratio. Alcohol consumption was positively associated with the n-6/n-3 ratio.

Conclusion

Early pregnancy BMI was positively associated with EPA+DHA and total n-3 PUFAs, while presenting a reduced weekly fish intake and a lower inter-partum interval were associated with lower levels of n-3 PUFAs. A lower per-capita family income and a drinking habit were factors that were positively associated with a higher n-6/n-3 ratio.     

Apoptosis-inducing factor of a cytotoxic T cell line: involvement of a secretory phospholipase A2

Natural killer (NK) cells and cytotoxic T lymphocytes (CTLs) kill target cells by the granule-exocytosis pathway and by the engagement of molecules belonging to the tumor necrosis factor family. The involvement of secretory phospholipase A₂ (sPLA₂) in the cytotoxic process has been proposed in NK cells. However, its molecular identity and intracellular localization remain unknown, and its mechanism of action is poorly understood. Here, we have readdressed this issue by studying the cytotoxic activity of whole cell extracts of a CTL line. We observed that inactivation of the perforin-granzyme pathway at 37°C in the presence of 1 mM Ca²⁺ enhanced the ability of CTL extracts to induce apoptosis. This potentiation of cell death was Ca²⁺-dependent, thermo-resistant, and inhibited by 4-bromophenacyl bromide and scalaradial (two inhibitors of sPLA₂). The involvement of an sPLA₂ was confirmed by blocking the pro-apoptotic activity of the Ca²⁺-treated cell extract with an anti-sPLA₂ polyclonal antibody. By cell fractionation assays, we showed that the pro-apoptotic sPLA₂ was localized in the cytoplasmic fraction but not in perforin-rich granules or plasma membrane fractions. Western blotting analysis revealed the presence of four distinct bands of 56, 29.5, 21, and 15 kDa. The highest molecular weight band was consistent with the expression of a group III sPLA2. Taken together, these data indicate that an apoptosis-inducing sPLA₂ is expressed in the cytosol of a CTL cell line and suggest that it plays an effector role in CTL-mediated cytotoxicity. This work was supported by the Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ), and Programa de Núcleos de Excelência (PRONEX–CNPq).     

A Two-Stage System for the Large-Scale Cultivation of Biomass: a Design and Operation Analysis Based on a Simple Steady-State Model Tuned on Laboratory Measurements

The optimal design and operation at large scale of a continuous fermentation process including a biological reactor/photobioreactor and a gravity settler with partial recycle and purge of the biomass are addressed. The proposed method is developed with reference to microalgae (Scenedesmus obliquus) cultivation, but it can be applied to any fermentation process as well as to activated sludge wastewater treatment. A procedure is developed to predict the effect of process variables, mainly the recycle ratio (R), the solid retention time (θ _c ), the reactor residence time (θ), and the ratio between feed and purge flow rates (F _I /F _W ). It includes a simple steady-state model of the two units coupled in the process and the experimental measurement of basic kinetic data, in both the bioreactor and the settler, for the tuning of model parameters. The bioreactor is assumed as perfectly mixed, and a rigorous gravity-flux approach is used for the settler. The process model is solved in terms of dimensionless variables, and plots are given to allow sensitivity analyses and optimization of operating conditions. A discussion about washout is presented, and a simple method is outlined for the calculation of the minimum values of residence time (θ _min ) and recycle ratio (R _min ) and of the maximum allowed recycle ratio (R _{max,operating} ) and biomass purge rate (F _Wmax ). In particular, it is shown that the system is sensitive to the concentration of biomass lost from the top of the settler (C _X ^S ). The proposed method can be useful for the design and analysis of large-scale processes of this type.     

A decade of malaria during pregnancy in Brazil: what has been done concerning prevention and management

In Brazil, malaria remains a disease of major epidemiological importance because ofthe high number of cases in the Amazonian Region. Plasmodium spp infections duringpregnancy are a significant public health problem with substantial risks for thepregnant woman, the foetus and the newborn child. In Brazil, the control of malariaduring pregnancy is primarily achieved by prompt and effective treatment of the acuteepisodes. Thus, to assure rapid diagnosis and treatment for pregnant women withmalaria, one of the recommended strategy for low transmission areas by World HealthOrganization and as part of a strategy by the Ministry of Health, the NationalMalaria Control Program has focused on integrative measures with woman andreproductive health. Here, we discuss the approach for the prevention and managementof malaria during pregnancy in Brazil over the last 10 years (2003-2012) usingmorbidity data from Malaria Health Information System. Improving the efficiency andquality of healthcare and education and the consolidation of prevention programmeswill be challenges in the control of malaria during pregnancy in the next decade.     

Effect of puberty on the relationship between bone markers of turnover and bone mineral density in Turner's syndrome

It has been suggested that the appropriate timing of puberty is necessary for normal bone mineral acquisition which may not be achieved amongst patients with Turner's syndrome (TS). The aim of this study was to assess bone mineral density (BMD) and bone turnover in 34 patients with TS (age range 2.2-39.0 years). The areal BMD (aBMD) was determined by dual-energy X-ray absorptiometry, and the volumetric BMD was calculated. Blood and second voided urine samples were taken the morning after an overnight fast for evaluation of the biochemical markers of bone turnover: bone-specific alkaline phosphatase (BAP) and N-telopeptides of type I collagen (NTX), respectively. Both were determined by enzyme-linked immunosorbent assay. The patients were divided into three groups: group 1 (n = 13; prepubertal; age range 2.2-19.0 years), group 2 (n = 10; teenagers; age range 12.4-19.0 years), and group 3 (n = 11; adults; chronological age >20 years). They were also grouped by breast development according to Tanner stage into B1 (n = 12), B2-3 (n = 9), and B4-5 (n = 13). The aBMD was significantly lower in group 1 and was higher at Tanner stages 4 and 5 as compared with patients at Tanner stage 1. The bone turnover markers were significantly higher in group 1 (NTX: p = 0.002; BAP: p = 0.0005) and declined, as puberty progressed. A negative correlation was observed between aBMD and biochemical bone markers at the lumbar spine (NTX: r = -0.54, p = 0.05; BAP: r = -0.44, p = 0.01) and in the whole body (NTX: r = -0.60, p = 0.0008; BAP: r = -0.19, p = 0.002). We conclude that the negative relationships between aBMD and biochemical markers suggest a high bone turnover, mainly in prepubertal patients and that the results observed in relation to aBMD and puberty are imputed to the delayed puberty which occurs amongst TS patients.