The Portuguese observatory on occupational psychosocial factors: contribution for public health

 

To achieve the goal of sustainable employment, considering the profile of the Portuguese working population (PWP), is needed a range of strategies to ensure long, productive, and sustainable careers allied with a better quality of working life, health, and wellbeing, but also with public health policies grounded on scientifically validated and reliable data. This is possible through a comprehensive working system approach that ensures workers will be mentally and physically able to remain at work by the balance between work demands and individual resources allied with public health policies transfer into the workplaces by organizations’ leadership and policy makers. The Portuguese Observatory on Occupational Factors (Popsy@Work) aims at addressing this global challenge by: i) digitally collecting psychosocial data on the PWP; ii) implementing and strengthening of a psychosocial occupational health surveillance digital system; iii) providing reference values for the PWP concerning Psychosocial Health; iv) Transferring to society knowledge and best practices; v) Raising awareness on the importance of psychosocial management in occupational settings based on science. Popsy@work is a digital platform that collects and aggregates psychosocial data analytically and creates a visualization hub adding value to data on the PWP and giving science back to society in a usable way, empowering workers, strengthening organizations and grounding public policies. Pospy@Work considers the development of strategic intelligence on levels and inequalities of psychosocial health and well-being in occupational settings by robust metrics and reference data. Creating opportunities for national policy dialogue on inequalities, including the psychosocial health of the PWP through collaboration with diverse sectors identifying and mapping subgroups of populations whose unmet needs require specific outreach measures.

Key messages

Insurance coverage gap for treatment of melasma compared to rosacea: it pays to be light

Treatments for many common dermatologic diagnoses are denied insurance coverage due to their arbitrary cosmetic classification. Melasma is one such diagnosis often considered cosmetic by payers, and since it is commonly identified in darker-skinned individuals, its cosmetic classification creates an economic barrier for patients of color. Although dermatologists have previously described insurance coverage gaps for conditions typically seen in patients of color, this coverage gap has never been quantified.¹ Thus, we investigated the rate of insurance coverage for first-line topical treatments for rosacea versus melasma. Rosacea and melasma share a number of key features - both are common, chronic, dermatological conditions that are exacerbated by sun exposure, are primarily treated topically, and cause measurably decreased quality of life in affected patients.^2,3 Rosacea, however, is often diagnosed in patients with Fitzpatrick skin types I-II, with 91.8% of rosacea diagnoses seen in white patients, while melasma is predominantly diagnosed in patients with Fitzpatrick skin types III-V.^4-6.

Effects of Bacillus subtilis and its metabolites on corn silage quality

Cellulolytic micro-organisms are potent silage inoculants that decrease the fibrous content in silage and increase the fibre digestibility and nutritional value of silage. This study aimed to evaluate the effects of Bacillus subtilis CCMA 0087 and its enzyme β-glucosidase on the nutritional value and aerobic stability of corn silage after 30 and 60 days of storage. We compared the results among silage without inoculant (SC) and silages inoculated with B. subtilis 8 log₁₀ CFU per kg forage (SB8), 9 log₁₀ CFU per kg forage (SB9) and 9·84 log₁₀ CFU per kg forage + β-glucosidase enzyme (SBE). No differences were observed in the levels of dry matter, crude protein and neutral detergent fibre due to the different treatments or storage times of the silos. Notably, the population of spore-forming bacteria increased in the SB9-treated silage. At 60 days of ensiling, the largest populations of lactic acid bacteria were found in silages treated with SB8 and SBE. Yeast populations were low for all silages, irrespective of the different treatments, and the presence of filamentous fungi was observed only in the SBE-treated silage. Among all silage treatments, SB9 treatment resulted in the highest aerobic stability.

Pseudothrombocytopenia: a case of platelet satellitism and phagocytosis by neutrophils

Thrombocytopenia is a clinically important condition that can lead to several problems when not correctly diagnosed. A decrease of platelet counts due to an in vitro phenomenon, Pseudothrombocytopenia, can be misunderstood and unnecessarily treated. The present case study describes a 57-year-old male with a history of pancreas adenocarcinoma and a current Staphylococcus aureus infection without any signs or symptoms that could explain the low levels of platelets obtained after blood analysis. Blood smear evaluation detected both platelet satellitism and phagocytosis by neutrophils. As this sample was anticoagulated with ethylenediaminetetraacetic acid (EDTA), a new blood sample with citrate was analyzed. Platelet count was normal and no morphological abnormalities were detected. This case emphasizes the need for considering not only laboratory results but also the patient clinical information to guarantee the correct diagnosis and the best treatment possible.

Biological control in the germination of seeds from two species native of the Cerrado region

Microorganisms have been efficiently used for the biological control of phytopathogens through the production of antimicrobial substances. However, the objectives of this work were: to study the germination of Butia purpurascens Glassman and Butia archeri Glassman seeds in different substrates, to select and identify the endophytic and rhizospheric bacterial isolates of B. purpurascens and B. archeri, and to perform antibiosis tests based on the isolated microorganisms of these tree species. No difference was found between the cultivation substrates for the percentages of germination, hard seeds, and fungal contamination in the B. purpurascens seeds. The Bacillus subtilis isolated showed the best capacity for suppressing the growth of the two deteriorative fungi tested in B. purpurascens seeds. No difference was found for inhibition of the growth of Aspergillus niger fungus (deteriorative fungus of B. archeri seeds) between the microorganisms with Bacillus sp. and Brevibacillus brevis compared to the control. In the microbiolization of B. purpurascens and B. archeri seeds performed with microbiological solutions produced from the endophytic and rhizospheric strains of Bacillus sp., no differences were observed in the percentages of germination and contamination by fungi. For B. archeri seeds, there was contamination by fungi and bacteria after one day of cultivation, primarily in the regions with lesions caused by the extraction and scarification process.

Event-related potentials modulated by the perception of sexual dimorphism: The influence of attractiveness and sex of faces

Sexual dimorphism has been proposed as one of the facial traits to have evolved through sexual selection and to affect attractiveness perception. Even with numerous studies documenting its effect on attractiveness and mate choice, the neurophysiological correlates of the perception of sexual dimorphism are not yet fully understood. In the present study, event-related potentials (ERPs) were recorded during visualisation of faces that had been previously transformed in shape to appear more masculine or more feminine. The participants' task consisted of judging the attractiveness of half of the total number of faces, and performing a sex discrimination task on the other half. Both early and late potentials were modulated by the sex of faces, whereas the effect of the sexually dimorphic transform was mainly visible in the P2 (positive deflection around 200 ms after stimulus onset), EPN (early posterior negativity) and LPP (late positive potential) components. There was an effect of sexual dimorphism on P2 and EPN amplitudes when female participants visualised male faces, which may indicate that masculinity is particularly attended to when viewing opposite sex members. Also, ERP results seem to support the idea of sex differences in social categorisation decisions regarding faces, although differences were not evident on behavioural results. In general, these findings contribute to a better understanding of how humans perceive sexually dimorphic characteristics in other individuals' faces and how they affect attractiveness judgements.

Revealing chemophoric sites in organophosphorus insecticides through the MIA-QSPR modeling of soil sorption data

Soil sorption of insecticides employed in agriculture is an important parameter to probe the environmental fate of organic chemicals. Therefore, methods for the prediction of soil sorption of new agrochemical candidates, as well as for the rationalization of the molecular characteristics responsible for a given sorption profile, are extremely beneficial for the environment. A quantitative structure-property relationship method based on chemical structure images as molecular descriptors provided a reliable model for the soil sorption prediction of 24 widely used organophosphorus insecticides. By means of contour maps obtained from the partial least squares regression coefficients and the variable importance in projection scores, key molecular moieties were targeted for possible structural modification, in order to obtain novel and more environmentally friendly insecticide candidates. The image-based descriptors applied encode molecular arrangement, atoms connectivity, groups size, and polarity; consequently, the findings in this work cannot be achieved by a simple relationship with hydrophobicity, usually described by the octanol-water partition coefficient.

Mixed yeasts inocula for simultaneous production of SCP and treatment of vinasse to reduce soil and fresh water pollution

This study evaluated the use of vinasse as a substrate for microbial biomass production and its disposal impact on the environment. After grown in vinasse, the microbial biomass (SCP) of two Saccharomyces cerevisiae strains, CCMA 0137 and CCMA 0188, showed high levels of essential amino acids (3.78%), varying levels of chemical elements, and low nucleic acid content (2.38%), i. e, good characteristics to food supplemements. Following biological treatment, spent vinasse biochemical oxygen demand (BOD) and chemical oxygen demand (COD) decreased to 51.56 and 29.29%, respectively. Cultivation with S. cerevisiae significantly reduced short term phytotoxicity and toxicity on soil microbiota of spent vinasse.

ERP correlates of error processing during performance on the Halstead Category Test

The Halstead Category Test (HCT) is a neuropsychological test that measures a person's ability to formulate and apply abstract principles. Performance must be adjusted based on feedback after each trial and errors are common until the underlying rules are discovered. Event-related potential (ERP) studies associated with the HCT are lacking. This paper demonstrates the use of a methodology inspired on Singular Spectrum Analysis (SSA) applied to EEG signals, to remove high amplitude ocular and movement artifacts during performance on the test. This filtering technique introduces no phase or latency distortions, with minimum loss of relevant EEG information. Importantly, the test was applied in its original clinical format, without introducing adaptations to ERP recordings. After signal treatment, the feedback-related negativity (FRN) wave, which is related to error-processing, was identified. This component peaked around 250ms, after feedback, in fronto-central electrodes. As expected, errors elicited more negative amplitudes than correct responses. Results are discussed in terms of the increased clinical potential that coupling ERP information with behavioral performance data can bring to the specificity of the HCT in diagnosing different types of impairment in frontal brain function.

Influence of the metabolic state on the tolerance of Pichia kudriavzevii to heavy metals

This work aims to examine the influence of the metabolic state of the yeast Pichia kudriavzevii on the susceptibility to a metals mixture (5 mg L^-1 Cd, 10 mg L^-1 Pb, and 5 mg L^-1 Zn). Cells exposed to the metals mixture in the presence of 25 mmol L^-1 glucose displayed a higher loss of membrane integrity and proliferation capacity, compared to cells incubated in the absence of glucose. The analysis of the effect of individual metals revealed that glucose increased the toxic effect of Cd marginally, and of Pb significantly. The increased susceptibility to heavy metals due to glucose was attenuated in the simultaneous presence of a mitochondrial respiration inhibitor such as sodium azide (NaN₃ ). ATP-depleted yeast cells, resulting from treatment with the non-metabolizable glucose analogue 2-deoxy-d-glucose, showed an increased susceptibility to heavy metals mixture. Pre-incubation of yeast cells with 1 or 1.5 mmol L^-1 Ca²⁺ reduced significantly (P < 0.05) the loss of membrane integrity induced by the metals mixture. These findings contribute to the understanding of metals mechanisms of toxicity in the non-conventional yeast P. kudriavzevii.

Mapping and validation of Xanthomonas citri subsp citri genes regulated by putative plant-inducible promoter box (PIP-box)

Citrus canker, caused by the Gram-negative bacterium Xanthomonas citri subsp citri (Xac), is a major disease affecting citriculture worldwide, because of the susceptibility of the host and the lack of efficient control methods. Previous studies have reported that some genes of phytopathogenic bacteria possess a consensus nucleotide sequence (TTCGC...N15...TTCGC) designated the "plant-inducible-promoter box" (PIP box) located in the promoter region, which is responsible for activating the expression of pathogenicity and virulence factors when the pathogen is in contact with the host plant. In this study, we mapped and investigated the expression of 104 Xac genes associated with the PIP box sequences using a macroarray analysis. Xac gene expression was observed during in vitro (Xac grown for 12 or 20 h in XAM1 induction medium) or in vivo (bacteria grown in orange leaves for 3 to 5 days) infection conditions. Xac grown in non-induction NB liquid medium was used as the control. cDNA was isolated from bacteria grown under the different conditions and hybridized to the macroarray, and 32 genes differentially expressed during the infection period (in vitro or in vivo induction) were identified. The macroarray results were validated for some of the genes through semi-quantitative RT-PCR, and the functionality of the PIP box-containing promoter was demonstrated by activating b-glucuronidase reporter gene activity by the PIP box-containing promoter region during Xac-citrus host interaction.

Impact of multi-metals (Cd, Pb and Zn) exposure on the physiology of the yeast Pichia kudriavzevii

Metal contamination of the environment is frequently associated to the presence of two or more metals. This work aimed to study the impact of a mixture of metals (Cd, Pb and Zn) on the physiology of the non-conventional yeast Pichia kudriavzevii. The incubation of yeast cells with 5 mg/l Cd, 10 mg/l Pb and 5 mg/l Zn, for 6 h, induced a loss of metabolic activity (assessed by FUN-1 staining) and proliferation capacity (evaluated by a clonogenic assay), with a small loss of membrane integrity (measured by trypan blue exclusion assay). The staining of yeast cells with calcofluor white revealed that no modification of chitin deposition pattern occurred during the exposure to metal mixture. Extending for 24 h, the exposure of yeast cells to metal mixture provoked a loss of membrane integrity, which was accompanied by the leakage of intracellular components. A marked loss of the metabolic activity and the loss of proliferation capacity were also observed. The analysis of the impact of a single metal has shown that, under the conditions studied, Pb was the metal responsible for the toxic effect observed in the metal mixture. Intracellular accumulation of Pb seems to be correlated with the metals' toxic effects observed.

Interplay between spin-glass clusters and geometrical frustration

The presence of spin-glass (SG) order in highly geometrically frustrated systems is analyzed in a cluster SG model. The model considers infinite-range disordered interactions among cluster magnetic moments and the J(1)-J(2) model couplings between Ising spins of the same cluster. This model can introduce two sources of frustration: one coming from the disordered interactions and another coming from the J(1)-J(2) intracluster interactions (intrinsic frustration). The framework of one-step replica symmetry breaking is adopted to obtain a one-cluster problem that is exactly solved. As a main result we create phase diagrams of the temperature T versus intensity of the disorder J, where the paramagnetic-SG phase transition occurs at T(f) when T decreases for high-J values. For low-J values, the SG order is absent for antiferromagnetic clusters without intrinsic frustration. However, the SG order can be observed within the intracluster intrinsic frustration regime even for lower intensity of disorder. In particular, the results indicate that the presence of small clusters in geometrically frustrated antiferromagnetic systems can help stabilize the SG order within a weak disorder.

Inverse freezing in a cluster Ising spin-glass model with antiferromagnetic interactions

Inverse freezing is analyzed in a cluster spin-glass (SG) model that considers infinite-range disordered interactions between magnetic moments of different clusters (intercluster interaction) and short-range antiferromagnetic coupling J(1) between Ising spins of the same cluster (intracluster interaction). The intercluster disorder J is treated within a mean-field theory by using a framework of one-step replica symmetry breaking. The effective model obtained by this treatment is computed by means of an exact diagonalization method. With the results we build phase diagrams of temperature T/J versus J(1)/J for several sizes of clusters n(s) (number of spins in the cluster). The phase diagrams show a second-order transition from the paramagnetic phase to the SG order at the freezing temperature T(f) when J(1)/J is small. The increase in J(1)/J can then destroy the SG phase. It decreases T(f)/J and introduces a first-order transition. In addition, inverse freezing can arise at a certain range of J(1)/J and large enough n(s). Therefore, the nontrivial frustration generated by disorder and short-range antiferromagnetic coupling can introduce inverse freezing spontaneously.

The effect of intracranial stent implantation on the curvature of the cerebrovasculature

BACKGROUND AND PURPOSE

Recently, the use of stents to assist in the coiling and repair of wide-neck aneurysms has been shown to be highly effective; however, the effect of these stents on the RC of the parent vessel has not been quantified. The purpose of this study was to quantify the effect of intracranial stenting on the RC of the implanted artery using 3D datasets.

MATERIALS AND METHODS

Twenty-four patients receiving FDA-approved neurovascular stents to support coil embolization of brain aneurysms were chosen for this study. The stents were located in the ICA, ACA, or MCA. We analyzed C-arm rotational angiography and contrast-enhanced cone beam CT datasets before and after stent implantation, respectively, to ascertain changes in vessel curvature. The images were reconstructed, and the vessel centerline was extracted. From the centerline, the RC was calculated.

RESULTS

The average implanted stent length was 25.4 ± 5.8 mm, with a pre-implantation RC of 7.1 ± 2.1 mm and a postimplantation RC of 10.7 ± 3.5 mm. This resulted in a 3.6 ± 2.7 mm change in the RC due to implantation (P < .0001), more than a 50% increase from the pre-implantation value. There was no difference in the change of RC for the different locations studied. The change in RC was not impacted by the extent of coil packing within the aneurysm.

CONCLUSIONS

The implantation of neurovascular stents can be shown to have a large impact on the RC of the vessel. This will lead to a change in the local hemodynamics and flow pattern within the aneurysm.

Closed-cell stent for coil embolization of intracranial aneurysms: clinical and angiographic results

BACKGROUND AND PURPOSE

Recanalization is observed in 20-40% of endovascularly treated intracranial aneurysms. To further reduce the recanalization and expand endovascular treatment, we evaluated the safety and efficacy of closed-cell SACE.

MATERIALS AND METHODS

Between 2007 and 2010, 147 consecutive patients (110 women; mean age, 54 years) presenting at 2 centers with 161 wide-neck ruptured and unruptured aneurysms were treated by using SACE. Inclusion criteria were wide-neck aneurysms (>4 mm or a dome/neck ratio ≤ 2). Clinical outcomes were assessed by the mRS score at baseline, discharge, and follow-up. Aneurysm occlusion was assessed on angiograms by using the RS immediately after SACE and at follow-up.

RESULTS

Eighteen aneurysms (11%) were treated following rupture. Procedure-related mortality and permanent neurologic deficits occurred in 2 (1.4%) and 5 patients (3.4%), respectively. In total, 7 patients (4.8%) died, including 2 with reruptures. Of the 140 surviving patients, 113 (80.7%) patients with 120 aneurysms were available for follow-up neurologic examination at a mean of 11.8 months. An increase in mRS score from admission to follow-up by 1, 2, or 3 points was seen in 7 (6.9%), 1 (1%), and 2 (2%) patients, respectively. Follow-up angiography was performed in 120 aneurysms at a mean of 11.9 months. Recanalization occurred in 12 aneurysms (10%), requiring retreatment in 7 (5.8%). Moderate in-stent stenosis was seen in 1 (0.8%), which remained asymptomatic.

CONCLUSIONS

This series adds to the evidence demonstrating the safety and effectiveness of SACE in the treatment of intracranial aneurysms. However, SACE of ruptured aneurysms and premature termination of antiplatelet treatment are associated with increased morbidity and mortality.

Mechanical characterization of thromboemboli in acute ischemic stroke and laboratory embolus analogs

BACKGROUND AND PURPOSE

Mechanical behavior of the thromboembolus is one of the key factors that determine the efficacy of thrombectomy devices for revascularization in AIS. We characterized the mechanical properties and composition of thromboemboli from clinical cases and compared them with commonly used EAs.

MATERIALS AND METHODS

Thromboemboli were obtained from patients with AIS by using aspiration devices and from carotid atherosclerotic plaques harvested during endarterectomy. In the laboratory, common EAs were created by varying blood donor species (human, porcine, and bovine), thrombin concentration, and presence of barium sulfate. Stiffness and elasticity of the specimens were measured with DMA. Scanning electron microscopy and histology were used to investigate the ultrastructure and composition of all specimens.

RESULTS

Red thromboemboli from patients composed mainly of fibrin and erythrocytes were much softer than the calcified and cholesterol-rich material. Of the EAs created in the laboratory, those made from bovine blood presented the highest stiffness that was independent of thrombin concentration. Addition of thrombin increased the stiffness and elasticity of human and porcine EAs (P < .05). The presence of barium sulfate significantly reduced the elasticity of all EAs (P < .05).

CONCLUSIONS

Endovascular device testing and development requires realistic EAs. The stiffness and elasticity of the cerebral thromboemboli analyzed in this study were closely matched by recalcified porcine EAs and thrombin-induced human EAs. Stiffness of the thrombus extracted from carotid endarterectomy specimens was similar with that of the thrombin-induced bovine and porcine EAs.

Using the residue of spirit production and bio-ethanol for protein production by yeasts

The residue (vinasse) formed during the distillation of bio-ethanol and cachaça, a traditional rum-type spirit produced from sugar-cane in Brazil, is highly harmful if discharged into the environment due to high values of COD and BOD. One possibility for minimizing the impact of vinasse in soils and waters is to use the residue in the production of microbial biomass for use as an animal feed supplement that will provide high levels on nitrogen (>9% d.m.) and low content of nucleic (≤ 10% d.m.) This paper reports the production and quality of biomass produced from fermentation of Saccharomyces cerevisiae and Candida parapsilosis in culture media under 12 different culture conditions and the respective effects of each variable (glucose, yeast extract, peptone, potassium phosphate, vinasse, pH and temperature). Of the S. cerevisiae isolates tested, two (VR1 and PE2) originating from fuel alcohol-producing plants were identified as offering the best potential for the industrial production of single cell protein from vinasse due to highest biomass productivity. Our results showed a potential viable and economic use of vinasse.

Diamidine activity against trypanosomes: the state of the art

Aromatic diamidines and related compounds are DNA minor groove binders that have been screened against a variety of pathogenic microorganisms such as bacteria, fungi and protozoa and show promising results. Parasitic infections are widespread in developing countries and are major contributors to human mortality and morbidity, causing considerable economic hardship. Trypanosomes are unicellular protozoan organisms that cause serious public health problems in developing countries: African trypanosomiasis (sleeping sickness) in Africa, and Chagas' disease, in Latin America. Sleeping sickness, caused by sub-species of Trypanosome brucei (T. brucei gambiense and T. brucei rhodesiense), is a fatal disease if left untreated, with about 60 million people currently at risk. Trypanosoma cruzi is the etiological agent of Chagas' disease, an important parasitic illness that affects nearly 17 million individuals in endemic areas. The fact that the available clinical drugs are expensive, toxic, require long treatment periods, frequently exhibit reduced activity towards certain parasite strains and evolutive stages, and are beginning to show development of resistance, demonstrates the urgent need for the development of new drugs for both pathologies. For some time much attention has been focused on the effect of diamidines (and related compounds) on African trypanosomes. However more recent studies have pointed to their potential activity against T.cruzi. In this review the current therapeutic state of the art of aromatic diamidines and related compounds used against T.brucei and T.cruzi is reviewed with a focus on their potential use as antiparasitic drugs for the treatment of both these important neglected diseases.

Features of Saccharomyces cerevisiae as a culture starter for the production of the distilled sugar cane beverage, cachaça in Brazil

AIMS

To evaluate the dominance and persistence of strains of Saccharomyces cerevisiae during the process of sugar cane fermentation for the production of cachaça and to analyse the microbial compounds produced in each fermentative process.

METHODS AND RESULTS

Three S. cerevisiae strains were evaluated during seven consecutive 24-h fermentation batches using recycled inocula. The UFLA CA 116 strain had the largest population of viable organisms, and the maximum population was achieved in the fourth batch after 96 h of fermentation. The UFLA CA 1162 and UFLA CA 1183 strains grew more slowly, and the maximum population was reached in the seventh batch. Molecular characterization of isolated yeast cells using PFGE (pulse field gel electrophoresis) revealed that more than 86% of the isolates corresponded to the initially inoculated yeast strain. The concentration of aldehydes, esters, methanol, alcohol and volatile acids in the final-aged beverages were within the legal limits.

CONCLUSIONS

Cachaça produced by select yeast strains exhibits analytical differences. UFLA CA 1162 and UFLA CA 116 S. cerevisiae isolates can be considered the ideal strains for the artisanal production of cachaça in Brazil.

SIGNIFICANCE AND IMPACT OF THE STUDY

The use of select yeast strains can improve the quality and productivity of cachaça production. Our findings are important for the appropriate monitoring of yeast during sugar cane fermentation. In addition, we demonstrate that UFLA CA 116 and UFLA CA 1162, the ideal yeast strains for cachaça production, are maintained at a high population density. The persistence of these yeast strains in the fermentation of sugar cane juice promotes environmental conditions that prevent or decrease bacterial contamination. Thus, the use of select yeast strains for the production of cachaça is a viable economic alternative to standardize the production of this beverage.

Microdialysis as a tool to determine free kidney levels of voriconazole in rodents: a model to study the technique feasibility for a moderately lipophilic drug

Microdialysis has been employed for the in vivo measurement of endogenous compounds and a variety of drugs in different tissues. The applicability of this technique can be limited by drug lipophilicity which can impair the diffusion through dialysis membrane. The objective of this study was to evaluate the feasibility of using microdialysis to study kidney penetration of voriconazole, a moderately lipophilic antifungal triazolic agent (LogD7.4=1.8). Microdialysis probe recoveries were investigated in vitro by dialysis and retrodialysis using four different drug concentrations (0.1-2 microg/mL) at five flow rates (1-5 microL/min). Recoveries were dependent on the method used for the determination as well as on the flow rate, but independent of drug concentration. The average apparent recoveries determined by dialysis and retrodialysis, at flow rate of 2 microL/min, were 21.1+/-1.5% and 28.7+/-2.0%, respectively. Recovery by retrodialysis was bigger than the recovery by dialysis. The average apparent dialysis/retrodialysis recovery ratio in vitro was 0.73 for all concentrations investigated. The differences between retrodialysis and dialysis recoveries were attributed to the drug's binding to the plastic tubing before and after the dialysis membrane which was experimentally evaluated and mathematically modeled. The in vivo apparent recovery determined by retrodialysis in healthy Wistar rats' kidney was 38.5+/-3.5%, similar to that observed in vitro using the same method (28.7+/-2.0%). The in vivo apparent recovery after correcting for plastic tubing binding (25.1+/-2.8%) was successfully used for determining free kidney levels of voriconazole in rats following 40 and 60mg/kg oral dosing. The results confirmed that microdialysis can be used as sampling technique to determine free tissue levels of moderately lipophilic drugs once the contribution of tubing binding and membrane diffusion on the apparent recovery are disentangled.

Cellular effects of reversed amidines on Trypanosoma cruzi

Aromatic diamidines represent a class of DNA minor groove-binding ligands that exhibit high levels of antiparasitic activity. Since the chemotherapy for Chagas' disease is still an unsolved problem and previous reports on diamidines and related analogues show that they have high levels of activity against Trypanosoma cruzi infection both in vitro and in vivo, our present aim was to evaluate the cellular effects in vitro of three reversed amidines (DB889, DB702, and DB786) and one diguanidine (DB711) against both amastigotes and bloodstream trypomastigotes of T. cruzi, the etiological agent of Chagas' disease. Our data show that the reversed amidines have higher levels of activity than the diguanidine, with the order of trypanocidal activities being as follows: DB889 > DB702 > DB786 > DB711. Transmission electron microscopy analysis showed that the reversed amidines induced many alterations in the nuclear morphology, swelling of the endoplasmic reticulum and Golgi structures, and consistent damage in the mitochondria and kinetoplasts of the parasites. Interestingly, in trypomastigotes treated with the reversed amidine DB889, multiple axoneme structures (flagellar microtubules) were noted. Flow cytometry analysis confirmed that the treated parasites presented an important loss of the mitochondrial membrane potential, as revealed by a decrease in rhodamine 123 fluorescence. Our results show that the reversed amidines have promising activities against the relevant mammalian forms of T. cruzi and display high trypanocidal effects at very low doses. This is especially the case for DB889, which merits further in vivo evaluation.

Activity of “reversed” diamidines against Trypanosoma cruzi “in vitro”

Chagas' disease is an important parasitic illness caused by the flagellated protozoan Trypanosoma cruzi. The disease affects nearly 17 million individuals in endemic areas of Latin America and the current chemotherapy is quite unsatisfactory based on nitroheterocyclic agents (nifurtimox and benznidazol). The need for new compounds with different modes of action is clear. Due to the broad-spectrum antimicrobial activity of the aromatic dicationic compounds, this study focused on the activity of four such diamidines (DB811, DB889, DB786, DB702) and a closely related diguanidine (DB711) against bloodstream trypomastigotes as well as intracellular amastigotes of T. cruzi in vitro. Additional studies were also conducted to access the toxicity of the compounds against mammalian cells in vitro. Our data show that the four diamidines compounds presented early and high anti-parasitic activity (IC50 in low-micromolecular range) exhibiting trypanocidal dose-dependent effects against both trypomastigote and amastigote forms of T. cruzi 2h after drug treatment. Most of the diamidines compounds (except the DB702) exerted high anti-parasitic activity and low toxicity to the mammalian cells. Our results show the activity of reversed diamidines against T. cruzi and suggested that the compounds merit in vivo studies.

Sand bar opening in a coastal lagoon (Iquipari) in the northern region of Rio De Janeiro State: hydrological and hydrochemical changes

The aim of this paper was to verify hydrological and hydrochemical changes in the Iquiparí Lagoon water column, during three months, as related to an artificial sand bar opening. A drastic reduction in water volume occurred 28 hours after the sand bar opening, exposing the bottom sediment. This was densely colonized by submerged aquatic plants, which were dominant in the ecosystem metabolism, specially near the sand bar. An increase in salinity values, and dissolved and total nutrient concentrations, was observed during the sand bar opening period. In contrast, chlorophyll a concentration decreased. These changes were associated with: 1) mix of remained brackish and marine waters; 2) nutrient release from sediments by physical processes; and 3) submerged plant death. After the sand bar closure, lagoon metabolism was completely regulated by a dense phytoplankton community. We observed that the sand bar opening resulted in an extensile replacement of the lagoon's water and a change in the community mainly responsible for the ecosystem metabolism.

Snoring in Portuguese primary school children

OBJECTIVE

To determine the prevalence of snoring and its potential associations with sleep problems, such as daytime symptoms, medical conditions, school performance, and behavioral disturbances in Portuguese children attending primary school.

METHODS

A previously validated questionnaire was sent to the parents of 1381 children attending primary schools in a parish of Coimbra, Portugal. To assess behavioral disturbances, the Portuguese version of Rutter's Children's Behavior Questionnaire for completion by teachers was used.

RESULTS

Of the 988 questionnaires returned (71.5%), complete information concerning snoring was obtained for 976 children (496 girls and 480 boys; mean age: 8.1 +/- 1.5 years). Loud snoring during sleep was reported as frequent or constantly present (LSn) in 84 children (8.6%), as occasionally present in 299 children (30.6%), and as never present (NSn) by 593 children (60.8%). The LSn and NSn groups did not differ with respect to age, gender, sleep duration, time to fall asleep, frequency of night wakings, bedwetting, daytime tiredness, and school achievement. However, LSn was significantly associated with increased bedtime problems (fears and struggles), increased need for comforting activities to fall asleep, behaviors suggestive of parasomnias (sleep talking, teeth grinding, and night terrors), increased daytime sleepiness and irritability, and behavioral disturbances. Children in the LSn group were also more likely to report recurrent medical problems particularly those involving infections of the respiratory tract.

CONCLUSIONS

Snoring is a common symptom in Portuguese children that is associated with behavioral daytime and sleep time disturbances. Children with loud snoring may benefit from early evaluation and intervention.