Showing papers by "Universidade Federal de Minas Gerais published in 2006"

Global biodiversity conservation priorities.

Abstract: The location of and threats to biodiversity are distributed unevenly, so prioritization is essential to minimize biodiversity loss. To address this need, biodiversity conservation organizations have proposed nine templates of global priorities over the past decade. Here, we review the concepts, methods, results, impacts, and challenges of these prioritizations of conservation practice within the theoretical irreplaceability/vulnerability framework of systematic conservation planning. Most of the templates prioritize highly irreplaceable regions; some are reactive (prioritizing high vulnerability), and others are proactive (prioritizing low vulnerability). We hope this synthesis improves understanding of these prioritization approaches and that it results in more efficient allocation of geographically flexible conservation funding.

Modelling conservation in the Amazon basin

Abstract: Deforestation is continuing in the Amazon basin as the cattle and soy industries expand. The main conservation policy there involves ‘protected areas’: areas designated by national governments that are left undisturbed to allow natural vegetation to develop. But this alone may not protect the rainforest ecosystem from collapse. An new estimate of forest losses made using the SimAmazonia 1 computer model suggests that by 2050, agricultural expansion will eliminate two-thirds of the forest cover of five major watersheds and ten ecoregions. One in four mammalian species examined will lose 40% of their forest habitat. Although an improved network of protected areas could avoid up to a third of projected forest loss, forest conservation on private properties will be essential if the Amazon landscapes and watersheds are to be maintained. Expansion of the cattle and soy industries in the Amazon basin has increased deforestation rates and will soon push all-weather highways into the region's core1,2,3,4. In the face of this growing pressure, a comprehensive conservation strategy for the Amazon basin should protect its watersheds, the full range of species and ecosystem diversity, and the stability of regional climates. Here we report that protected areas in the Amazon basin—the central feature of prevailing conservation approaches5,6,7,8—are an important but insufficient component of this strategy, based on policy-sensitive simulations of future deforestation. By 2050, current trends in agricultural expansion will eliminate a total of 40% of Amazon forests, including at least two-thirds of the forest cover of six major watersheds and 12 ecoregions, releasing 32 ± 8 Pg of carbon to the atmosphere. One-quarter of the 382 mammalian species examined will lose more than 40% of the forest within their Amazon ranges. Although an expanded and enforced network of protected areas could avoid as much as one-third of this projected forest loss, conservation on private lands is also essential. Expanding market pressures for sound land management and prevention of forest clearing on lands unsuitable for agriculture are critical ingredients of a strategy for comprehensive conservation3,4.

The tension between authoritative and dialogic discourse: A fundamental characteristic of meaning making interactions in high school science lessons

Abstract: In this paper, we draw upon a framework for analyzing the discursive interactions of science classrooms (Mortimer & Scott, 2003, Meaning Making in Secondary Science Classrooms, Maidenhead, UK: Open University Press), to probe the movement between authoritative and dialogic discourse in a Brazilian high school science class. More specifically, we argue the point that such shifts between communicative approaches are an inevitable part of teaching whose purpose is to support meaningful learning of scientific knowledge. We suggest that a necessary tension therefore exists between authoritative and dialogic approaches as dialogic exchanges are followed by authoritative interventions (to develop the canonical scientific view), and the authoritative introduction of new ideas is followed by the opportunity for dialogic application and exploration of those ideas. In these ways, one communicative approach follows from the other, authoritativeness acting as a seed for dialogicity and vice versa. We discuss how this analysis, in terms of shifts in communicative approach, offers a new and complementary perspective on supporting “productive disciplinary engagement” (Engle & Conant, 2002, Cognition and Instruction, 20, 399–484) in the classroom. Finally we consider some methodological issues arising from this study. © 2006 Wiley Periodicals, Inc. Sci Ed90:605–631, 2006

Prevalence and risk variables for peri-implant disease in Brazilian subjects.

Abstract: Objectives: The aim of this study was to verify the prevalence of peri-implant disease and analyse possible risk variables associated with peri-implant mucositis and peri-implantitis. The study group consisted of 212 partially edentulous subjects rehabilitated with osseointegrated implants. Material and Methods: The implants placed were examined clinically and radiographically to assess the peri-implant status. The degree of association between peri-implant disease and various independent variables was investigated using a multinomial regression analysis. Results: The prevalence of peri-implant mucositis and peri-implantitis were 64.6% and 8.9%, respectively. In univariate modelling, healthy peri-implant subjects presented lower plaque scores, less periodontal bleeding on probing, and less time elapsed since placement of supra-structures. In multivariate analyses, the risk variables associated with increased odds for having peri-implant disease included: gender, plaque scores, and periodontal bleeding on probing. Presence of periodontitis and diabetes were statistically associated with increased risk of peri-implantitis. The only two factors, which did not contribute to the presence of the disease, were the time elapsed since placement of supra-structures and the frequency of visits for maintenance care. Conclusion: Our data suggest that subjects with periodontitis, diabetes, and poor oral hygiene were more prone to develop peri-implantitis.

An elliptic spatial scan statistic

Abstract: The spatial scan statistic is commonly used for geographical disease cluster detection, cluster evaluation and disease surveillance. The most commonly used shape of the scanning window is circular. In this paper we explore an elliptic version of the spatial scan statistic, using a scanning window of variable location, shape (eccentricity), angle and size, and with and without an eccentricity penalty. The method is applied to breast cancer mortality data from Northeastern United States and female oral cancer mortality in the United States. Power comparisons are made with the circular scan statistic.

Bibliometria: evolução histórica e questões atuais

Abstract: Promove-se uma analise do campo de conhecimento intitulado bibliometria Inicialmente, sao vistas as tres leis fundadoras do campo, a lei de produtividade de autores de Lotka, a lei de dispersao de periodicos de Bradford e a lei de frequencia de palavras de Zipf, bem como seus desdobramentos e aplicacoes em tempos recentes Sao tambem vistos a teoria epidemica e a analise de citacoes, em suas aplicacoes contemporâneas, como por exemplo os estudos de frente de pesquisa e fator de impacto Por fim, analisa-se o desenvolvimento deste campo de estudos no Brasil e as tendencias atuais, com destaque para as abordagens que buscam ampliar o escopo dos estudos realizados integrando os metodos bibliometricos a distintos corpos teoricos

Corynebacterium pseudotuberculosis: microbiology, biochemical properties, pathogenesis and molecular studies of virulence

Abstract: Corynebacterium pseudotuberculosis is the etiological agent of caseous lymphadenitis (CLA), a common disease in small ruminant populations throughout the world. Once established, this disease is difficult to eradicate because drug therapy is not effective and because the clinical detection of infected animals is of limited efficiency. We reviewed the microbiological, biochemical and taxonomic features of C. pseudotuberculosis, general aspects of infection, the main virulence determinants and currently available commercial vaccines. We also examined the current molecular strategies for the study of virulence in C. pseudotuberculosis, including the latest research on the identification of novel virulence factors and genes, which will help us to better understand the biology of this microorganism. This knowledge may also contribute to the development of improved CLA vaccines, including subunit and DNA-based types, as well as to improve the diagnosis, treatment and control of this disease.

Changing patterns of acute hematogenous osteomyelitis and septic arthritis: emergence of community-associated methicillin-resistant Staphylococcus aureus.

Abstract: INTRODUCTION: An increase in the incidence and severity of acute osteoarticular infections in children was perceived after the emergence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) in our community. This study was performed to describe changes in the epidemiology and clinical features of acute osteoarticular infections. METHODS: The records of patients discharged from Le Bonheur Children's Medical Center with a diagnosis of acute osteoarticular infection between 2000 and 2004 were reviewed. Data regarding signs and symptoms, diagnostic testing, therapeutics, surgery, and hospital course were collected. RESULTS: There were 158 cases of acute osteoarticular infection. The incidence increased from 2.6 to 6.0 per 1000 admissions between 2000 and 2004. The proportion of infections caused by methicillin-susceptible S. aureus (MSSA) remained constant (10%-13%) and that caused by MRSA rose from 4% to 40%. There was no difference between MRSA and MSSA patients in the duration of fever or pain before diagnosis. Seventy-one percent of patients with MRSA had subperiosteal abscesses compared with 38% with MSSA (P = 0.02). Ninety-one percent of MRSA patients required a surgical procedure compared with 62% of MSSA patients (P < 0.001). Median hospital stay was 7 days for MSSA patients and 10 days for MRSA patients (P = 0.0001). Three patients developed chronic osteomyelitis, 2 with MRSA. There was no association between a delay in institution of appropriate antibiotic therapy and presence of subperiosteal abscess (P = 0.8). CONCLUSIONS: There has been an increase in the incidence and severity of acute osteoarticular infections in Memphis. Patients with community-associated MRSA infections are at higher risk of subperiosteal abscess requiring surgical intervention.

Protozoan encounters with Toll-like receptor signalling pathways: implications for host parasitism

Abstract: Toll-like receptors (TLRs) have emerged as a major receptor family involved in non-self recognition. They have a vital role in triggering innate immunity and orchestrate the acquired immune response during bacterial and viral infection. However, the role of TLRs during infection with protozoan pathogens is less clear. Nevertheless, our understanding of how these parasitic microorganisms engage the host TLR signalling system has now entered a phase of rapid expansion. This Review describes recent insights into how parasitic protozoans are sensed by TLR molecules, and how the TLR system itself can be targeted by these microbial pathogens for their own survival.

Cutting edge: TLR9 and TLR2 signaling together account for MyD88-dependent control of parasitemia in Trypanosoma cruzi infection.

Abstract: Activation of innate immune cells by Trypanosoma cruzi-derived molecules such as GPI anchors and DNA induces proinflammatory cytokine production and host defense mechanisms. In this study, we demonstrate that DNA from T. cruzi stimulates cytokine production by APCs in a TLR9-dependent manner and synergizes with parasite-derived GPI anchor, a TLR2 agonist, in the induction of cytokines by macrophages. Compared with wild-type animals, T. cruzi-infected Tlr9(-/-) mice displayed elevated parasitemia and decreased survival. Strikingly, infected Tlr2(-/-)Tlr9(-/-) mice developed a parasitemia equivalent to animals lacking MyD88, an essential signaling molecule for most TLR, but did not show the acute mortality displayed by MyD88(-/-) animals. The enhanced susceptibility of Tlr9(-/-) and Tlr2(-/-)Tlr9(-/-) mice was associated with decreased in vivo IL-12/IFN-gamma responses. Our results reveal that TLR2 and TLR9 cooperate in the control of parasite replication and that TLR9 has a primary role in the MyD88-dependent induction of IL-12/IFN-gamma synthesis during infection with T. cruzi.

Antibacterial activity of coffee extracts and selected coffee chemical compounds against enterobacteria.

Abstract: The in vitro antimicrobial activity of commercial coffee extracts and chemical compounds was investigated on nine strains of enterobacteria. The antimicrobial activity investigated by the disc diffusion method was observed in both the extracts and tested chemical compounds. Even though pH, color, and the contents of trigonelline, caffeine, and chlorogenic acids differed significantly among the coffee extracts, no significant differences were observed in their antimicrobial activity. Caffeic acid and trigonelline showed similar inhibitory effect against the growth of the microorganisms. Caffeine, chlorogenic acid, and protocatechuic acid showed particularly strong effect against Serratia marcescens and Enterobacter cloacae. The IC50 and IC90 for the compounds determined by the microtiter plate method indicated that trigonelline, caffeine, and protocatechuic acids are potential natural antimicrobial agents against Salmonella enterica. The concentrations of caffeine found in coffee extracts are enough to war...

Specific stabilisation exercise for spinal and pelvic pain: a systematic review

Abstract: The aim of this study was to conduct a systematic review of the efficacy of specific stabilisation exercise for spinal and pelvic pain. Randomised clinical trials evaluating specific stabilisation exercise were identified and retrieved. Outcomes were disability, pain, return to work, number of episodes, global perceived effect, or health-related quality of life. A single trial reported that specific stabilisation exercise was more effective than no treatment but not more effective than spinal manipulative therapy for the management of cervicogenic headache and associated neck pain. Single trials reported that specific stabilisation exercise was effective for pelvic pain and for prevention of recurrence after an acute episode of low back pain but not to reduce pain or disability associated with acute low back pain. Pooled analyses revealed that, for chronic low back pain, specific stabilisation exercise was superior to usual medical care and education but not to manipulative therapy, and no additional effect was found when specific stabilisation exercise was added to a conventional physiotherapy program. A single trial reported that specific stabilisation exercise and a surgical procedure to reduce pain and disability in chronic low back pain were equally effective. The available evidence suggests that specific stabilisation exercise is effective in reducing pain and disability in chronic but not acute low back pain. Single trials indicate that specific stabilisation exercise can be helpful in the treatment of cervicogenic headache and associated neck pain, pelvic pain, and in reducing recurrence after acute low back pain.

Synthesis and characterization of poly (vinyl alcohol) hydrogels and hybrids for rMPB70 protein adsorption

Abstract: Polyvinyl alcohol (PVA), PVA crosslinked with glutaraldehyde hydrogels (PVA/GA), PVA with tetraethylorthosilicate (PVA/TEOS) and PVA/GA/TEOS hybrids with recombinant MPB70 protein (rMPB70) incorporated were chemically characterized by Fourier transform infrared spectroscopy (FTIR). FTIR spectra of PVA hydrogel samples showed the absorption regions of the specific chemical groups associated with poly(vinyl alcohol) (-OH, -CO, -CH2) and PVA/GA confirming the formation of crosslinked hydrogel (duplet -CH). It was observed C-H broad alkyl stretching band (n = 2850-3000 cm-1) and typical strong hydroxyl bands for free alcohol (nonbonded -OH stretching band at n = 3600-3650 cm-1), and hydrogen bonded band (n = 3200-3570 cm-1). The most important vibration bands related to silane alcoxides have been verified on FTIR spectra of PVA/TEOS and PVA/GA/TEOS hybrids (Si-O-Si, n = 1080 and n = 450 cm-1; Si-OH, n = 950 cm-1). FTIR spectra of f PVA hydrogel with rMPB70 incorporated have indicated the specific groups usually found in protein structures, such as amides I, II and III, at 1680-1620 cm-1, 1580-1480 cm-1 and 1246 cm-1, respectively. These results have given strong evidence that recombinant protein rMPB70 was successfully adsorbed in the hydrogels and hybrids networks. These PVA based hydrogels and hybrids were further used in immunological assays (Enzyme-Linked Immunosorbent Assay - ELISA). Tests were performed to detect antibodies against rMPB70 protein in serum samples from bovines that were positive in the tuberculin test. Corresponding tests were carried out without PVA samples in microtiter plates as control. Similar results were found for commercially available microplates and PVA based hydrogels and hybrids developed in the present work regarding to immunoassay sensitivity and specificity response.

New tools for surveillance of adult yellow fever mosquitoes: comparison of trap catches with human landing rates in an urban environment

Abstract: A novel mosquito trapping system, the BG-Sentinel® trap, was evaluated as a monitoring tool for adult Aedes aegypti in field tests in the city of Belo Horizonte, Brazil. Human landing/biting collections, a gas-powered CO2 trap, and a Fay-Prince trap with only visual cues serving as references to evaluate the efficacy of the new trap. The BG-Sentinel is a simple suction trap that uses upward-directed air currents as well as visual cues to attract mosquitoes. The trap was tested with a new dispenser system (BG-Lure®) that releases artificial human skin odors and needs no CO2. In comparison with the two other traps, the BG-Sentinel caught significantly more Ae. aegypti. Although human landing rates were the highest, there was no significant difference between human landing rates and the capture rates of the BG-Sentinel trap. This finding indicates that the trap can be considered as an acceptable alternative to human landing/biting collections in the surveillance of adult host- seeking dengue vectors...

Mycobacterium bovis bacillus Calmette-Guérin induces TLR2-mediated formation of lipid bodies: intracellular domains for eicosanoid synthesis in vivo.

Abstract: Differentiation of macrophages into foamy (lipid-laden) macrophages is a common pathological observation in tuberculous granulomas both in experimental settings as well as in clinical conditions; however, the mechanisms that regulate intracellular lipid accumulation in the course of mycobacterial infection and their significance to pathophysiology of tuberculosis are not well understood. In this study, we investigated the mechanisms of formation and function of lipid-laden macrophages in a murine model of tuberculosis. Mycobacterium bovis bacillus Calmette-Guerin (BCG), but not Mycobacterium smegmatis, induced a dose- and time-dependent increase in lipid body-inducible nonmembrane-bound cytoplasmic lipid domain size and numbers. Lipid body formation was drastically inhibited in TLR2-, but not in TLR4-deficient mice, indicating a role for TLR2 in BCG recognition and signaling to form lipid bodies. Increase in lipid bodies during infection correlated with increased generation of PGE2 and localization of cyclooxygenase-2 within lipid bodies. Moreover, we demonstrated by intracellular immunofluorescent localization of newly formed eicosanoid that lipid bodies were the predominant sites of PGE2 synthesis in activated macrophages. Our findings demonstrated that BCG-induced lipid body formation is TLR2 mediated and these structures function as signaling platforms in inflammatory mediator production, because compartmentalization of substrate and key enzymes within lipid bodies has impact on the capacity of activated leukocytes to generate increased amounts of eicosanoids during experimental infection by BCG.

Parkinsonism and Parkinson's disease in the elderly: a community-based survey in Brazil (the Bambuí study).

Abstract: Several community-based surveys on the prevalence of Parkinsonism and Parkinson's disease have been conducted worldwide, with variations on their methodology and results. The objective of this study is to assess the prevalence of Parkinsonism and its causes in a cohort of individuals age 64 years or older in Bambui, a Brazilian town. In phase I, 1,186 people older than 64 years responded to a 9-question screening questionnaire for Parkinsonism. In phase II, all subjects who scored ≥ 2 points on the test were examined independently by at least 2 movement disorder-trained physicians. A movement disorder senior specialist excluded or confirmed the diagnosis in all suspected cases. The response rate was high for both phases (96% for phase I and 94% for phase II). The prevalence rate per 100 population over 64 years of age in this group was 7.2% for Parkinsonism of all types (n = 86). The most frequent causes were idiopathic Parkinson's disease and drug-induced Parkinsonism, with prevalence rates of 3.3% (n = 39) and 2.7% (n = 32), respectively. The prevalence of vascular Parkinsonism was 1.1% (n = 13). We found 1 case of posttraumatic Parkinsonism and another with multiple system atrophy. In this first population-based study of Parkinsonism conducted in Brazil, the prevalence in a cohort of elderly subjects was higher than the observed in other populations worldwide, especially because of the high rates of drug-induced and vascular Parkinsonism. The prevalence of Parkinson's disease was similar to that observed in elderly people in door-to-door surveys in other American, European, and Eastern countries. © 2006 Movement Disorder Society

Cytokine expression profile over time in severely burned pediatric patients.

Abstract: A severe burn leads to hypermetabolism and catabolism resulting in compromised function and structure of essential organs. The massive release of cytokines is implicated in this hypermetabolic response. The aim of the present study was to compare cytokine expression profiles from severely burned children without signs of infections or inhalation injury (n = 19) to the cytokine profiles from normal, noninfected, nonburned children (n = 14). The Bio-Plex suspension array system was used to measure the concentration of 17 cytokines. The expression of proinflammatory and anti-inflammatory cytokines was maximal during the first week after thermal injury. Significant increases were measured for 15 mediators during the first week after thermal injury: interleukin (IL) 1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 p70, IL-13, IL-17, interferon gamma, monocyte chemoattractant protein 1, macrophage inflammatory protein 1beta, and granulocyte colony-stimulating factor (P < 0.05). Granulocyte-macrophage colony-stimulating factor was significantly increased during the second week after burn (P < 0.05). Within 5 weeks, the serum concentrations of most cytokines decreased, approaching normal levels. When compared with the cytokine levels measured in normal children, a total of 16 cytokines were significantly altered (P < 0.05). After severe burn, a specific cytokine expression profile is observed in patients without complications such as inhalation injury or sepsis. The cytokine concentrations decrease during 5 weeks after burn but remain elevated over nonburned values. Furthermore, the elevation in most serum cytokine levels during the first week after burn may indicate a potential window of opportunity for therapeutic intervention.

Hipertensão arterial no Brasil: estimativa de prevalência a partir de estudos de base populacional

Abstract: Endereço para correspondência: Departamento de Clínica Médica, Faculdade de Medicina da Universidade Federal de Minas Gerais, Av. Alfredo Balena, 190, sala 4082, Belo Horizonte-MG. CEP: 30190-100 E-mail: vpassos@medicina.ufmg.br Resumo Estudos epidemiológicos sobre a hipertensão arterial são fundamentais para conhecer a distribuição da exposição e do adoecimento e as condições que influenciam a dinâmica de risco e controle na comunidade. Este artigo analisa estudos de prevalência de hipertensão no Brasil, de base populacional, em adultos, a partir de 1990. Foram incluídos todos os estudos publicados nas bases Medline e LILACS. A análise considerou a população-alvo, o desenho do estudo, o plano amostral, as características sociodemográficas da população-alvo, os critério de definição de hipertensão e a análise estatística. Nos 13 estudos selecionados, as taxas de prevalência mostram que cerca de 20% dos adultos apresentam hipertensão, sem distinção por sexo, mas também com evidente tendência de aumento com a idade. Os estudos ainda estão restritos às Regiões Sul e Sudeste. É marcante a preocupação com a metodologia e precisão da estimativa da prevalência. Ainda são escassos, entretanto, estudos sobre conhecimento, tratamento e controle da hipertensão. Palavras-chave: hipertensão; prevalência; estudos de base populacional.

Oral tolerance: therapeutic implications for autoimmune diseases.

Abstract: Oral tolerance is classically defined as the suppression of immune responses to antigens (Ag) that have been administered previously by the oral route. Multiple mechanisms of tolerance are induced by oral Ag. Low doses favor active suppression, whereas higher doses favor clonal anergy/deletion. Oral Ag induces Th2 (IL-4/IL-10) and Th3 (TGF-b) regulatory T cells (Tregs) plus CD4þCD25þ regulatory cells and LAPþT cells. Induction of oral tolerance is enhanced by IL-4, IL-10, anti-IL-12, TGF-b, cholera toxin B subunit (CTB), Flt-3 ligand, anti-CD40 ligand and continuous feeding of Ag. In addition to oral tolerance, nasal tolerance has also been shown to be effective in suppressing inflammatory conditions with the advantage of a lower dose requirement. Oral and nasal tolerance suppress several animal models of autoimmune diseases including experimental allergic encephalomyelitis (EAE), uveitis, thyroiditis, myasthenia, arthritis and diabetes in the nonobese diabetic (NOD) mouse, plus non-autoimmune diseases such as asthma, atherosclerosis, colitis and stroke. Oral tolerance has been tested in human autoimmune diseases including MS, arthritis, uveitis and diabetes and in allergy, contact sensitivity to DNCB, nickel allergy. Positive results have been observed in phase II trials and new trials for arthritis, MS and diabetes are underway. Mucosal tolerance is an attractive approach for treatment of autoimmune and inflammatory diseases because of lack of toxicity, ease of administration over time and Ag-specific mechanism of action. The successful application of oral tolerance for the treatment of human diseases will depend on dose, developing immune markers to assess immunologic effects, route (nasal versus oral), formulation, mucosal adjuvants, combination therapy and early therapy.

Ancestral genomes, sex, and the population structure of Trypanosoma cruzi.

Abstract: Acquisition of detailed knowledge of the structure and evolution of Trypanosoma cruzi populations is essential for control of Chagas disease. We profiled 75 strains of the parasite with five nuclear microsatellite loci, 24Sα RNA genes, and sequence polymorphisms in the mitochondrial cytochrome oxidase subunit II gene. We also used sequences available in GenBank for the mitochondrial genes cytochrome B and NADH dehydrogenase subunit 1. A multidimensional scaling plot (MDS) based in microsatellite data divided the parasites into four clusters corresponding to T. cruzi I (MDS-cluster A), T. cruzi II (MDS-cluster C), a third group of T. cruzi strains (MDS-cluster B), and hybrid strains (MDS-cluster BH). The first two clusters matched respectively mitochondrial clades A and C, while the other two belonged to mitochondrial clade B. The 24Sα rDNA and microsatellite profiling data were combined into multilocus genotypes that were analyzed by the haplotype reconstruction program PHASE. We identified 141 haplotypes that were clearly distributed into three haplogroups (X, Y, and Z). All strains belonging to T. cruzi I (MDS-cluster A) were Z/Z, the T. cruzi II strains (MDS-cluster C) were Y/Y, and those belonging to MDS-cluster B (unclassified T. cruzi) had X/X haplogroup genotypes. The strains grouped in the MDS-cluster BH were X/Y, confirming their hybrid character. Based on these results we propose the following minimal scenario for T. cruzi evolution. In a distant past there were at a minimum three ancestral lineages that we may call, respectively, T. cruzi I, T. cruzi II, and T. cruzi III. At least two hybridization events involving T. cruzi II and T. cruzi III produced evolutionarily viable progeny. In both events, the mitochondrial recipient (as identified by the mitochondrial clade of the hybrid strains) was T. cruzi II and the mitochondrial donor was T. cruzi III.

Seminar on choreas

Abstract: Summary Chorea is one of the major types of involuntary movement disorders originating from dysfunctional neuronal networks interconnecting the basal ganglia and frontal cortical motor areas. The syndrome is characterised by a continuous flow of random, brief, involuntary muscle contractions and can result from a wide variety of causes. Diagnostic work-up can be straightforward in patients with a positive family history of Huntington's disease or acute-onset hemichorea in patients with lacunar stroke, but it can be a challenging and complex task in rare autoimmune or genetic choreas. Principles of management focus on establishing an aetiological classification and, if possible, removal of the cause. Preventive strategies may be possible in Huntington's disease where genetic counselling plays a major part. In this review we summarise the current understanding of the neuroanatomy and pathophysiology of chorea, its major aetiological classes, and principles of diagnostic work-up and management.

Malaria risk on the Amazon frontier

Abstract: Frontier malaria is a biological, ecological, and sociodemographic phenomenon operating over time at three spatial scales (micro/individual, community, and state and national). We explicate these linkages by integrating data from remote sensing surveys, ground-level surveys and ethnographic appraisal, focusing on the Machadinho settlement project in Rondonia, Brazil. Spatially explicit analyses reveal that the early stages of frontier settlement are dominated by environmental risks, consequential to ecosystem transformations that promote larval habitats of Anopheles darlingi. With the advance of forest clearance and the establishment of agriculture, ranching, and urban development, malaria transmission is substantially reduced, and risks of new infection are largely driven by human behavioral factors. Malaria mitigation strategies for frontier settlements require a combination of preventive and curative methods and close collaboration between the health and agricultural sectors. Of fundamental importance is matching the agricultural potential of specific plots to the economic and technical capacities of new migrants. Equally important is providing an effective agricultural extension service.

O rápido processo de envelhecimento populacional do Brasil: sérios desafios para as políticas públicas

Abstract: The positive effects of the recent age structure transition (AST) in Brazil can be seen in children’s health services, education and other areas. The higher growth rate estimated for the economically active population in coming decades constitutes a new area of opportunities. The combination of the older segment of the labor force (ages 25 to 64), which is showing high growth, with the junior segment (ages 15 to 24), which is showing very low or even negative growth rates, indicates a trend toward reducing the demographic pressure for new jobs. The training of the future labor force has become an indispensable component for a more just intergenerational, social and economic balance. Due to the age structure transition, new challenges are emerging related to the expansion of the older population. If the present per capita transfer of funds from the government is maintained constant, the difference between revenue and expenses will increase, causing an unsustainable fiscal deficit. The expected crisis brought about by the aging of the population and the current irrational social security system must be urgently discussed in Brazilian society. The best must be made of the opportunities generated by age structure transition in order to prepare to face the new resulting challenges.