Universidade Federal de Minas Gerais

About: Universidade Federal de Minas Gerais is a education organization based out in Belo Horizonte, Minas Gerais, Brazil. It is known for research contribution in the topics: Population & Immune system. The organization has 41631 authors who have published 75688 publications receiving 1249905 citations.

Early and protective microglial activation in Alzheimer's disease: a prospective study using 18F-DPA-714 PET imaging.

Abstract: While emerging evidence suggests that neuroinflammation plays a crucial role in Alzheimer's disease, the impact of the microglia response in Alzheimer's disease remains a matter of debate. We aimed to study microglial activation in early Alzheimer's disease and its impact on clinical progression using a second-generation 18-kDa translocator protein positron emission tomography radiotracer together with amyloid imaging using Pittsburgh compound B positron emission tomography. We enrolled 96 subjects, 64 patients with Alzheimer's disease and 32 controls, from the IMABio3 study, who had both (11)C-Pittsburgh compound B and (18)F-DPA-714 positron emission tomography imaging. Patients with Alzheimer's disease were classified as prodromal Alzheimer's disease (n = 38) and Alzheimer's disease dementia (n = 26). Translocator protein-binding was measured using a simple ratio method with cerebellar grey matter as reference tissue, taking into account regional atrophy. Images were analysed at the regional (volume of interest) and at the voxel level. Translocator protein genotyping allowed the classification of all subjects in high, mixed and low affinity binders. Thirty high+mixed affinity binders patients with Alzheimer's disease were dichotomized into slow decliners (n = 10) or fast decliners (n = 20) after 2 years of follow-up. All patients with Alzheimer's disease had an amyloid positive Pittsburgh compound B positron emission tomography. Among controls, eight had positive amyloid scans (n = 6 high+mixed affinity binders), defined as amyloidosis controls, and were analysed separately. By both volumes of interest and voxel-wise comparison, 18-kDa translocator protein-binding was higher in high affinity binders, mixed affinity binders and high+mixed affinity binders Alzheimer's disease groups compared to controls, especially at the prodromal stage, involving the temporo-parietal cortex. Translocator protein-binding was positively correlated with Mini-Mental State Examination scores and grey matter volume, as well as with Pittsburgh compound B binding. Amyloidosis controls displayed higher translocator protein-binding than controls, especially in the frontal cortex. We found higher translocator protein-binding in slow decliners than fast decliners, with no difference in Pittsburgh compound B binding. Microglial activation appears at the prodromal and possibly at the preclinical stage of Alzheimer's disease, and seems to play a protective role in the clinical progression of the disease at these early stages. The extent of microglial activation appears to differ between patients, and could explain the overlap in translocator protein binding values between patients with Alzheimer's disease and amyloidosis controls.

Ants on plants: a meta-analysis of the role of ants as plant biotic defenses

Abstract: We reviewed the evidence on the role of ants as plant biotic defenses, by conducting meta-analyses for the effects of experimental removal of ants on plant herbivory and fitness with data pooled from 81 studies. Effects reviewed were plant herbivory, herbivore abundance, hemipteran abundance, predator abundance, plant biomass and reproduction in studies where ants were experimentally removed (n = 273 independent comparisons). Ant removal exhibited strong effects on herbivory rates, as plants without ants suffered almost twice as much damage and exhibited 50% more herbivores than plants with ants. Ants also influenced several parameters of plant fitness, as plants without ants suffered a reduction in biomass (-23.7%), leaf production (-51.8%), and reproduction (-24.3%). Effects were much stronger in tropical regions compared to temperate ones. Tropical plants suffered almost threefold higher herbivore damage than plants from temperate regions and exhibited three times more herbivores. Ant removal in tropical plants resulted in a decrease in plant fitness of about 59%, whereas in temperate plants this reduction was not statistically significant. Ant removal effects were also more important in obligate ant-plants (=myrmecophytes) compared to plants exhibiting facultative relationships with hemiptera or those plants with extrafloral nectaries and food bodies. When only tropical plants were considered and the strength of the association between ants and plants taken into account, plants with obligate association with ants exhibited almost four times higher herbivory compared to plants with facultative associations with ants, but similar reductions in plant reproduction. The removal of a single ant species increased plant herbivory by almost three times compared to the removal of several ant species. Altogether, these results suggest that ants do act as plant biotic defenses, but the effects of their presence are more pronounced in tropical systems, especially in myrmecophytic plants.

The impact of business analytics on supply chain performance

Abstract: The paper investigates the relationship between analytical capabilities in the plan, source, make and deliver area of the supply chain and its performance using information system support and business process orientation as moderators. Structural equation modeling employs a sample of 310 companies from different industries from the USA, Europe, Canada, Brazil and China. The findings suggest the existence of a statistically significant relationship between analytical capabilities and performance. The moderation effect of information systems support is considerably stronger than the effect of business process orientation. The results provide a better understanding of the areas where the impact of business analytics may be the strongest.

The Phylogeography of Brazilian Y-Chromosome Lineages

Abstract: We examined DNA polymorphisms in the nonrecombining portion of the Y-chromosome to investigate the contribution of distinct patrilineages to the present-day white Brazilian population. Twelve unique-event polymorphisms were typed in 200 unrelated males from four geographical regions of Brazil and in 93 Portuguese males. In our Brazilian sample, the vast majority of Y-chromosomes proved to be of European origin. Indeed, there were no significant differences when the haplogroup frequencies in Brazil and Portugal were compared by means of an exact test of population differentiation. Y-chromosome typing was quite sensitive in the detection of regional immigration events. Distinct footprints of Italian immigration to southern Brazil, migration of Moroccan Jews to the Amazon region, and possible relics of the 17th-century Dutch invasion of northeast Brazil could be seen in the data. In sharp contrast with our mtDNA data in white Brazilians, which showed that ⩾60% of the matrilineages were Amerindian or African, only 2.5% of the Y-chromosome lineages were from sub-Saharan Africa, and none were Amerindian. Together, these results configure a picture of strong directional mating between European males and Amerindian and African females, which agrees with the known history of the peopling of Brazil since 1500.

Peri‐implant disease in subjects with and without preventive maintenance: a 5‐year follow‐up

Abstract: Costa F. O., Takenaka-Martinez S., Cota L. O. M., Ferreira S. D., Silva G. L.M., Costa J. E., Peri-implant disease in subjects with and without preventivemaintenance: a 5-year follow-up. J Clin Periodontol 2011; doi: 10.1111/j.1600-051X.2011.01819.x.AbstractAim: To determine the incidence of peri-implantitis in individuals with mucositisin a 5-year follow-up study.Material and Methods: A sample of 212 partially edentulous individuals, rehabili-tated with dental implants, underwent periodontal and peri-implant clinical exam-inations in 2005 (baseline). Five years later, 80 individuals who had beendiagnosed with mucositis in the baseline examination were re-examined. Theseindividuals were divided into two groups: one group with preventive maintenanceduring the study period (GTP; n = 39), and another group without preventivemaintenance (GNTP; n = 41). The following parameters were clinically evaluated:plaque index, bleeding on periodontal and peri-implant probing, periodontal andperi-implant probing depth, suppuration and peri-implant bone loss. The influ-ence of biological and behavioural risk variables associated with the occurrenceof peri-implantitis was analysed using univariate and multivariate logistic regres-sion analyses.Results: The incidence of peri-implantitis in the global sample was 31.2%(GNTP = 43.9% and GTP = 18.0%).Conclusion: The absence of preventive maintenance in individuals with pre-exist-ing peri-implant mucositis was associated with a high incidence of peri-implanti-tis. Clinical parameters, such as bleeding on peri-implant probing, periodontalprobing depth and the presence of periodontitis were associated with a higher riskof developing peri-implantitis.