731 research outputs found
Water balance in a neotropical forest catchment of southeastern Brazil
Brazilian Atlantic Forest is recognized by the UNESCO as one of the most important biosphere reserves on the planet but is threatened by extinction. The objective of this study was to analyze the main components of the water balance in an Atlantic Forest (Neotropical Forest) catchment in the Mantiqueira Range, Brazil, which is a Tropical Montane Cloud Forest. The main focuses was to analyze baseflow, evapotranspiration, soil moisture, and canopy rainfall interception to understand the hydrologic dynamics in this specially important montane forest. On average from the two studied hydrological years (2009/2010 and 2010/2011), evapotranspiration (ET), streamflow (SF), and water storage in the catchment at the end of hydrological year corresponded, respectively, to 50%, 34.8% and 15.2% of total gross precipitation (P). On average, baseflow corresponded to 73.5% of SF. The estimated potential groundwater recharge during the wet seasons was 403.8mm (21.7% of P observed in the wet season) and 710.5mm (28.5% of P observed in the wet season), respectively, for 2009/2010 and 2010/2011 hydrological years, showing that the catchment is able to store groundwater to provide the maintenance of the streamflow during early recessions and drought periods. Therefore, the baseflow is important in mountainous catchments in the tropical regions to provide important ecological functions, mainly as freshwater reserve
Hydatidiform mole resulting from sexual violence
<p>Abstract</p> <p>Background</p> <p>Hydatidiform mole (HM) is characterized by abnormal proliferation of human trophoblast with producers functioning tissues of human chorionic gonadotropin. It can evolve with ovarian cysts tecaluteínicos, hypertension of pregnancy or hyperthyroidism. The incidence of HM is variable and its etiology poorly known, associated with nutritional factors, environmental, age, parity, history of HM, oral contraceptives, smoking, consanguinity or defects in germ cells. There is no reference in literature on HM resulting from sexual violence, objective of this report.</p> <p>Method</p> <p>Description of two cases of HM among 1146 patients with pregnancy resulting from sexual violence treated at Hospital Pérola Byington, São Paulo, from July 1994 to August 2011.</p> <p>Results</p> <p>The cases affected young, white, unmarried, low educated and low parity women. Sexual violence was perpetrated by known offenders unrelated to the victims, under death threat. Ultrasound and CT of the pelvis showed bulky uterus compatible with HM without myometrial invasion. One case was associated with theca lutein cysts. The two cases were diagnosed in the second trimester of pregnancy and evolved with hyperthyroidism. There was no hypertension, disease recurrence, metastasis or sexually transmitted infection.</p> <p>Conclusion</p> <p>The incidence of HM was 1:573 pregnancies resulting from rape, within the range estimated for Latin American countries. Trophoblastic material can be preserved to identify the violence perpetrator, considering only the paternal HM chromosomes. History of sexual violence should be investigated in cases of HM in the first half of adolescence and women in a vulnerable condition.</p
[C-11]PIB PET imaging can detect white and grey matter demyelination in a non-human primate model of progressive multiple sclerosis
Background: Multiple sclerosis (MS) is a demyelinating and inflammatory disease of the central nervous system. Its diagnosis is clinical, often confirmed by magnetic resonance imaging. This image modality, however, is not ideal for discrimination of demyelination in grey and white matter regions from inflammatory lesions. Positron Emission Tomography (PET), using specific radiopharmaceuticals, can be a tool to differentiate between these processes. The radiopharmaceutical [C-11]PIB is widely used for detection of beta-amyloid plaques, but has also been suggested for the analysis of myelin content due to its consistent uptake in white matter. The aim of this study was to evaluate [C-11]PIB PET imaging as a tool for detecting demyelinated regions in white and grey matter of non-human primate model of progressive MS. Methods: Experimental autoimmune encephalomyelitis (EAE) was induced in marmosets by injection of re-combinant human myelin oligodendrocyte glycoprotein (rhMOG) emulsified in either Incomplete Freund's Adjuvant (IFA) or Complete Freund's Adjuvant (CFA). [C-11]PIB PET images were acquired prior to immunization (baseline) and after symptoms were present (end of experiment). Brain tissue was isolated for histochemical analysis. Results: All rhMOG/IFA-treated and rhMOG/CFA-treated animals showed clinical signs of EAE. The rhMOG/CFA group presented a significant [C-11]PIB uptake reduction only in the left motor cortex (9%, P = 0.011). For the rhMOG/IFA group, significant decrease in [C-11]PIB uptake was observed in the whole brain (15%, P = 0.015), in the right hemisphere of body of corpus callosum (34%, P = 0.02), splenium of corpus callosum (38%, P = 0.004), hippocampus (19%, P = 0.036), optic tract (13%, P = 0.025), thalamus (14%, P = 0.041), Globus pallidus (23%, P = 0.017), head of caudate nucleus (25%, P = 0.045), tail of caudate nucleus (29%, P = 0.003), putamen (28%, P = 0.047) and left hemisphere of body of corpus callosum (14%, P = 0.037) and head of caudate nucleus (23%, P = 0.023). [C-11]PIB uptake significantly correlated with luxol fast blue histology (myelin marker), both in the rhMOG/IFA (r(2) = 0.32, P <0.0001) and the rhMOG/CFA group (r(2) = 0.46, P <0.0001). Conclusion: [C-11]PIB PET imaging is an efficient tool for detecting demyelination in grey and white matter, in a non-human primate model of progressive MS
Variable frequency of LRRK2 variants in the Latin American research consortium on the genetics of Parkinson's disease (LARGE-PD), a case of ancestry
ABSTARCT: Mutations in Leucine-Rich Repeat Kinase 2 (LRRK2), primarily located in codons G2019 and R1441, represent the most common genetic cause of Parkinson's disease in European-derived populations. However, little is known about the frequency of these mutations in Latin American populations. In addition, a prior study suggested that a LRRK2 polymorphism (p.Q1111H) specific to Latino and Amerindian populations might be a risk factor for Parkinson's disease, but this finding requires replication. We screened 1734 Parkinson's disease patients and 1097 controls enrolled in the Latin American Research Consortium on the Genetics of Parkinson's disease (LARGE-PD), which includes sites in Argentina, Brazil, Colombia, Ecuador, Peru, and Uruguay. Genotypes were determined by TaqMan assay (p.G2019S and p.Q1111H) or by sequencing of exon 31 (p.R1441C/G/H/S). Admixture proportion was determined using a panel of 29 ancestry informative markers. We identified a total of 29 Parkinson's disease patients (1.7%) who carried p.G2019S and the frequency ranged from 0.2% in Peru to 4.2% in Uruguay. Only two Parkinson's disease patients carried p.R1441G and one patient carried p.R1441C. There was no significant difference in the frequency of p.Q1111H in patients (3.8%) compared to controls (3.1%; OR 1.02, p = 0.873). The frequency of LRRK2-p.G2019S varied greatly between different Latin American countries and was directly correlated with the amount of European ancestry observed. p.R1441G is rare in Latin America despite the large genetic contribution made by settlers from Spain, where the mutation is relatively common
Hepatitis B virus genotypes circulating in Brazil: molecular characterization of genotype F isolates
<p>Abstract</p> <p>Background</p> <p>Hepatitis B virus (HBV) isolates have been classified in eight genotypes, A to H, which exhibit distinct geographical distributions. Genotypes A, D and F are predominant in Brazil, a country formed by a miscegenated population, where the proportion of individuals from Caucasian, Amerindian and African origins varies by region. Genotype F, which is the most divergent, is considered indigenous to the Americas. A systematic molecular characterization of HBV isolates from different parts of the world would be invaluable in establishing HBV evolutionary origins and dispersion patterns. A large-scale study is needed to map the region-by-region distribution of the HBV genotypes in Brazil.</p> <p>Results</p> <p>Genotyping by PCR-RFLP of 303 HBV isolates from HBsAg-positive blood donors showed that at least two of the three genotypes, A, D, and F, co-circulate in each of the five geographic regions of Brazil. No other genotypes were identified. Overall, genotype A was most prevalent (48.5%), and most of these isolates were classified as subgenotype A1 (138/153; 90.2%). Genotype D was the most common genotype in the South (84.2%) and Central (47.6%) regions. The prevalence of genotype F was low (13%) countrywide. Nucleotide sequencing of the S gene and a phylogenetic analysis of 32 HBV genotype F isolates showed that a great majority (28/32; 87.5%) belonged to subgenotype F2, cluster II. The deduced serotype of 31 of 32 F isolates was <it>adw4</it>. The remaining isolate showed a leucine-to-isoleucine substitution at position 127.</p> <p>Conclusion</p> <p>The presence of genotypes A, D and F, and the absence of other genotypes in a large cohort of HBV infected individuals may reflect the ethnic origins of the Brazilian population. The high prevalence of isolates from subgenotype A1 (of African origin) indicates that the African influx during the colonial slavery period had a major impact on the circulation of HBV genotype A currently found in Brazil. Although most genotype F isolates belonged to cluster II, the presence of some isolates belonging to clusters I (subgroup Ib) and IV suggests the existence of two or more founder viral populations of genotype F in Brazil.</p
Prevalence, treatment, and control of dyslipidemia in diabetic participants of two Brazilian cohorts: a place far from heaven
Diabetes is one of the leading causes of cardiovascular mortality. Over the last years, mortality has decreased significantly, more in individuals with diabetes than in healthy ones. That is mostly due to the control of other cardiovascular risk factors. The objective of our study was to analyze the dyslipidemia control in two diabetes cohorts. Patients from two distinct cohorts were studied, 173 patients from the BHS (Brasilia Heart Study) and 222 patients from the BDS (Brazilian Diabetes Study). The data on dyslipidemia control were studied in both different populations. All patients had diabetes. There are significant differences concerning comorbidities between the LDL-C and BDS groups. The average glycated hemoglobin is of 8.2 in the LDL-C > 100 group in comparison with 7.7 and 7.5 in the 70-100 and 100 groups (54.3% and 54.9%, respectively; p = 0.005). Diastolic pressure is higher in the group with LDL > 100, with an average of 87 mmHg, in comparison with 82.6 mmHg and 81.9 mmHg in the 70-100 and 100 has the greatest percentage of smokers (8.7%) in comparison with the groups with LDL between 70-100 and 100 groups, respectively (p < 0.001). The data in our study have shown that the dyslipidemia control in diabetic patients is inadequate and there is a tendency of direct association between lack of blood glucose control and lack of dyslipidemia control, in addition to the association with other cardiovascular risk factors, such as diastolic hypertension and smoking. This worsened control might be related to the plateau in the descending curve of mortality, and investments in this regard can improve the cardiovascular health in diabetic patients.6513
Very Low Mass Stellar and Substellar Companions to Solar-Like Stars From MARVELS V: A Low Eccentricity Brown Dwarf from the Driest Part of the Desert, MARVELS-6b
We describe the discovery of a likely brown dwarf (BD) companion with a
minimum mass of 31.7 +/- 2.0 M_Jup to GSC 03546-01452 from the MARVELS radial
velocity survey, which we designate as MARVELS-6b. For reasonable priors, our
analysis gives a probability of 72% that MARVELS-6b has a mass below the
hydrogen-burning limit of 0.072 M_Sun, and thus it is a high-confidence BD
companion. It has a moderately long orbital period of 47.8929 +0.0063/-0.0062
days with a low eccentricty of 0.1442 +0.0078/-0.0073, and a semi-amplitude of
1644 +12/-13 m/s. Moderate resolution spectroscopy of the host star has
determined the following parameters: T_eff = 5598 +/- 63, log g = 4.44 +/-
0.17, and [Fe/H] = +0.40 +/- 0.09. Based upon these measurements, GSC
03546-01452 has a probable mass and radius of M_star = 1.11 +/- 0.11 M_Sun and
R_star = 1.06 +/- 0.23 R_Sun with an age consistent with less than ~6 Gyr at a
distance of 219 +/- 21 pc from the Sun. Although MARVELS-6b is not observed to
transit, we cannot definitively rule out a transiting configuration based on
our observations. There is a visual companion detected with Lucky Imaging at
7.7 arcsec from the host star, but our analysis shows that it is not bound to
this system. The minimum mass of MARVELS-6b exists at the minimum of the mass
functions for both stars and planets, making this a rare object even compared
to other BDs.Comment: 15 pages, 15 figures, 5 tables. Accepted for publication in The
Astronomical Journa
- …