Frequency of BRAF V600E immunoexpression in ameloblastomas: a multi-institutional analysis of 86 cases in Latin America and comprehensive review of the literature.

BACKGROUND: The initiation of odontogenic tumorigenesis often involves the activation of the MAP-kinase pathway, with a pivotal role played by the BRAF V600E mutation. This study aimed to investigate the frequency of BRAF V600E immunoexpresion in ameloblastomas diagnosed in four Latin American centers and correlate this finding with the histological types and subtypes of the analyzed cases. MATERIAL AND METHODS: A total of 86 samples of ameloblastomas were examined for immunohistochemistry using anti-BRAF V600E antibody. The histopathological features of each case were analyzed. RESULTS:  Positivity for anti-BRAF V600E antibody was detected in 65/86 cases (75.6%). BRAF V600E was positive in 38/56 cases (67.9%) of conventional ameloblastomas and in 27/30 cases (90.0%) of unicystic ameloblastomas. A statistically significant difference in BRAF V600E positivity was observed when comparing unicystic ameloblastomas to conventional ameloblastomas (p=0.03). No statistically significant difference in BRAF V600E positivity was observed when comparing histological variants, both for conventional ameloblastomas and unicystic ameloblastomas. CONCLUSIONS: This study highlights a high frequency of BRAF V600E immunoreactivity in ameloblastomas among Latin American cases. The prevalence of the BRAF V600E immunoexpresion may suggest the feasibility of utilizing BRAF-targeted therapy for ameloblastomas with this mutation.

Fundamental solution of diffusion equation for Kappa gas: Diffusion length for suprathermal electrons in solar wind.

A recent numerical treatment of data obtained by the Parker Solar Probe spacecraft describes the electron concentration in solar wind as a function of the heliocentric distance based on a Kappa distribution with spectral index κ=5. In this work, we derive and, subsequently, solve an entirely different class of nonlinear partial differential equations describing the one-dimensional diffusion of a suprathermal gas. The theory is applied to describe the aforementioned data and we find a spectral index κ≳1.5 providing the widely acknowledged identification of Kappa electrons in solar wind. We also find that suprathermal effects increase the length scale of classical diffusion by one order of magnitude. Such a result does not depend on the microscopic details of the diffusion coefficient since our theory is based on a macroscopic formulation. Forthcoming extensions of our theory by including magnetic fields and relating our formulation to nonextensive statistics are briefly addressed.

ATPergic signaling disruption in human sepsis as a potential source of biomarkers for clinical use.

Sepsis is a life-threatening organ dysfunction caused by a dysregulated inflammatory response to infection. To date, there is no specific treatment established for sepsis. In the extracellular compartment, purines such as adenosine triphosphate (ATP) and adenosine play essential roles in the immune/inflammatory responses during sepsis and septic shock. The balance of extracellular levels among ATP and adenosine is intimately involved in the signals related to immune stimulation/immunosuppression balance. Specialized enzymes, including CD39, CD73, and adenosine deaminase (ADA), are responsible to metabolize ATP to adenosine which will further sensitize the P2 and P1 purinoceptors, respectively. Disruption of the purinergic pathway had been described in the sepsis pathophysiology. Although purinergic signaling has been suggested as a potential target for sepsis treatment, the majority of data available were obtained using pre-clinical approaches. We hypothesized that, as a reflection of deregulation on purinergic signaling, septic patients exhibit differential measurements of serum, neutrophils and monocytes purinergic pathway markers when compared to two types of controls (healthy and ward). It was observed that ATP and ADP serum levels were increased in septic patients, as well as the A2a mRNA expression in neutrophils and monocytes. Both ATPase/ADPase activities were increased during sepsis. Serum ATP and ADP levels, and both ATPase and ADPase activities were associated with the diagnosis of sepsis, representing potential biomarkers candidates. In conclusion, our results advance the translation of purinergic signaling from pre-clinical models into the clinical setting opening opportunities for so much needed new strategies for sepsis and septic shock diagnostics and treatment.

Stafne's bone defect: a systematic review.

BACKGROUND: This systematic review integrated the available data published in the literature on Stafne's bone defect (SBD), considering the clinical, imaging and histopathological results. MATERIAL AND METHODS: An electronic search was undertaken in six databases. Eligibility criteria were: articles in English, Spanish, and Portuguese describing case reports or case series of SBD, reported up to September/2021. Risk of bias was assessed using the Joanna Briggs Institute tool. RESULTS: A total of 98 articles were retrieved, involving 465 individuals with SBD and were included for quantitative analysis. Mean age was 52.78 years (range: 11-89 years), with male predilection (n=374/80.85%). Radiographs were the most frequent imagiological exams (n=298/64.09%), followed by computed tomography (n=98/21.08%). SBD was more prevalent in the posterior mandible (n=361/93.77%) as a hypodense radiolucent lesion (n=250/77.40%). Mean size was 1.58 cm (range: 0.3-.8.0 cm). Two-hundred-and-two lesions (97.37%) were unilocular and 126 (91.97%) were classified as well-defined. Clinical symptoms were reported in 73 cases, while 68 cases (93.15%) were asymptomatic. Only 34 cases (12.32%) were submitted to histopathological examination. Mean follow-up time was 26.42 ±25.39 months. CONCLUSIONS: SBD is more frequent in male patients in the fifth and sixth decade of life. Classic SBD is radiographically characterized as a single, unilocular and well-defined lesion in the posterior region of the jaw with a radiolucent/hypodense appearance.

Bilateral facial palsy with paresthesias, variant of Guillain-Barré syndrome following COVID-19 vaccine: A case series of 9 patients.

Several cases of Guillain-Barré Syndrome (GBS) associated with COVID-19 vaccination have been reported, including the rare subtype known as Bilateral Facial Palsy with paresthesias (BFP). To date, it is not known whether a causal relationship may exist between the two. We report 9 cases of BFP in patients vaccinated against COVID-19 in the previous month. Nerve conduction studies revealed demyelinating polyneuropathy in 4 patients, and 5 presented bilateral, focal facial nerve involvement, exclusively. Ganglioside antibody panel was positive in 4 patients (anti-GM1=2, anti-GD1a=1 and anti-sulfatide=1). Seven patients received intravenous immunoglobulin treatment, one plasma exchange, and one patient died from sudden cardiac arrest following arrhythmia before treatment could be administered. Rates of BFP following COVID-19 vaccination, did not differ from those reported in previous series. Epidemiological studies are essential to determine whether a causal relationship may exist between this rare form of GBS and COVID-19 vaccination.

Sex-dependent GOAL screening performance in adults at risk for obstructive sleep apnea.

OBJECTIVE: To evaluate possible sex-related differences in the performance of the GOAL, a 4-item obstructive sleep apnea (OSA) screening instrument in adults. METHODS: Between July 2019 and June 2021, this cross-sectional study included consecutively recruited patients from one Brazilian sleep laboratory undergoing overnight polysomnography. Individuals with GOAL scores ≥ 2 of a maximum of 4 points are classified at high risk for OSA diagnosis. Actual OSA severity was based on the apnea-hypopnea index: ≥ 5.0/h as any OSA, ≥ 15.0/h as moderate-to-severe OSA, and ≥ 30.0/h as severe OSA. Performance of the GOAL instrument in women and men was assessed by the discriminatory ability (obtained from area under the curve [AUC]-Receiver Operating Characteristic curves) and 2×2 contingency tables. RESULTS: A total of 2,978 subjects (55.3% males) were evaluated. The frequency of GOAL-defined OSA high-risk was statistically higher in men when compared to women (p < 0.001). The GOAL predictive parameters for screening all severity OSA levels were as follows: in females, sensitivity ranging from 58.2% to 78.3% and specificity ranging from 60.0% to 77.6%, while in males, sensitivity ranging from 90.5% to 96.9% and specificity from 20.7% to 46.8%. The GOAL questionnaire had similar discriminatory properties, assessed by AUC, in women and in men: i) any OSA: 0.741 vs. 0.771 (p = 0.204), ii) moderate-to-severe OSA: 0.727 vs. 0.737 (p = 0.595), and iii) severe OSA: 0.728 vs. 0.703 (p = 0.240); respectively. CONCLUSIONS: The GOAL instrument emerges as a useful tool for screening adult individuals and displays similar performance in both women and men.

Suplementação gestacional na produção de lã de ovelhas e cordeiros / Gestacional supplementation in wool production of ewes and lambs

O objetivo deste estudo foi avaliar o efeito da suplementação durante diferentes períodos gestacionais sobre a produção de lã de ovelhas e cordeiros da raça Ideal. Foram utilizadas 53 ovelhas da raça Ideal, com escore corporal médio (3), inseminadas pela técnica de laparoscopia, com sêmen fresco de um único reprodutor; e seus cordeiros. Os tratamentos experimentais foram: sem suplementação (n=9); suplementação do início da gestação até 50 dias (n=11); suplementação dos 51 aos 100 dias de gestação (n=11); suplementação dos 101 aos 150 dias - final da gestação (n=11); e suplementação durante toda a gestação (n=11). A suplementação foi a 1,5% do peso corporal. Amostras de lã das ovelhas e dos cordeiros foram tomadas na região do costilhar esquerdo e enviadas ao laboratório para análises objetivas de finura de lã. As suplementações no terço final e durante toda a gestação proporcionavam os melhores resultados, com aumento de produção de lã e de peso das ovelhas. Ovelhas que receberam suplementação durante toda a gestação apresentaram maior diâmetro de fibra e peso corporal. O desempenho de lã dos cordeiros não foi influenciado pela alimentação de ovelhas durante a gestação.(AU)

The objective of this study was to evaluate the effect of supplementation during different gestational periods on the wool production of sheep and lambs of the Ideal breed. Fifty-three adult Ideal sheep were used, with a mean body score inseminated by the laparoscopy technique using fresh sperm from a single breeder and his lambs. Treatment groups: No supplementation (n=9); Supplementation in the beginning of gestation up to 50 days (n=11); Supplementation from 51 to 100 days of gestation (n=11); Supplementation from 101 to 150 days - end of gestation (n=11) ;and Supplementation throughout the gestation (n=11). The supplementation was at 1.5% of body weight. After birth, lambs were kept with their mothers in cultivated pasture of black oats and ryegrass. Wool samples from sheep and lambs were taken in the left-hand region and sent to the laboratory for objective analyzes of wool fineness. The supplementation performed in the final third and throughout the gestation provides the best results, with increased sheep weight. Ewes that received supplementation throughout pregnancy had greater fiber diameter and body weight. The wool performance of lambs was not influenced by feeding sheep during gestation.(AU)

Outcome of temporary tracheostomy tube-placement following surgery for brachycephalic obstructive airway syndrome in 42 dogs.

OBJECTIVES: To describe the use, complications and outcome of temporary tracheostomy tube placement as part of the management of acute upper airway obstruction in the postoperative period following multi-level airway surgery in patients with brachycephalic obstructive airway syndrome. MATERIALS AND METHODS: Retrospective review of records of dogs surgically treated for brachycephalic obstructive airway syndrome that had a temporary tracheostomy tube placed in the postoperative period. RESULTS: Forty-two dogs were included. Median duration of temporary tracheostomy tube placement was 2 days (range 1 to 7). The major complication rate was 83.3%, minor complication rate was 71.4%, resulting in an overall postoperative complication rate of 95.2%. The most common postoperative complications were tracheostomy tube obstruction (32/42), cough (25/42) and tracheostomy tube dislodgement (16/42). Temporary tracheostomy tube management was classified as successful in 97.6%. Dyspnoea was the most common clinical sign in the short-term postoperative follow-up period, while dyspnoea and increased upper respiratory tract noise were the most common clinical sign in the long term. The median duration of follow-up was 251 days. CLINICAL SIGNIFICANCE: In an appropriate clinical setting, placement of temporary tracheostomy tubes following multi-level airway surgery for brachycephalic obstructive airway syndrome is a useful strategy to manage postoperative airway obstruction, carrying a low mortality rate, and with a complication rate similar to that found in previous reports.

Awareness on oral cancer among patients attending dental school clinics in Brazil.

BACKGROUND: Oral cancer is considered a public health problem worldwide. Dental schools may play an important role in educating patients about oral cancer. This study aimed at evaluating the knowledge of patients attending clinics at two dental schools in Brazil. MATERIAL AND METHODS: From March 2017 to April 2017, 251 patients who were attending clinics at two dental schools in Recife, Brazil, were included in the study. Patients were contacted in the waiting rooms of the clinic. Each participant completed a self-administered questionnaire, which consists of 21 questions, including socio-demographic and specific information on the disease. Data were analyzed using descriptive statistics, and a chi-square test (with a 5% significance level) was used to assess the correlation between the variables, education and family income and other variables. RESULTS: Most participants were women (64.9%) with a mean age of 42.72 years. Most participants were knowledgeable about oral cancer and identified tobacco use (48.6%), alcohol consumption (25.1%), and solar radiation (12%) as the primary risk factors for the disease. Only 36.7% of the participants reported having received counselling on oral cancer, of which 18.3% received the information from a dentist. All patients with an income higher than six minimum wages were aware about oral cancer (p = 0.001). CONCLUSIONS: These findings emphasize the importance of educational programs in dental schools as well providing integrated services for patients seeking care at school clinics, including population's awareness on oral cancer.

One for all and all for one: retention of colour-unchanged old flowers increases pollinator attraction in a hermaphroditic plant.

Long-lived flowers increase pollen transfer rates, but these entail high water and carbon maintenance costs. The retention of pollinated and reward-free old flowers enhances pollinator visitation to young receptive flowers by increasing floral display size. This mechanism is associated with acropetal inflorescences or changes in flower colour and openness, but the retention of unchanging solitary flowers remains overlooked. We examined pollination-dependent variation in floral longevity and determined stigmatic receptivity, pollen viability and pollen removal rates among flower ages in Kielmeyera regalis, a Neotropical savanna shrub. We also evaluated the effects of floral display size on pollinator visitation rates. Lastly, we determined whether old flowers are unvisited and exclusively increase pollinator attraction to young flowers through flower removal experiments. Regardless of pollination treatment, flowers lasted fully open with no detectable physical changes for 3 days. Over time, stigmas remained receptive but >95% of pollen was removed. Pollinator visitation significantly increased with floral display size and intermediate percentages (15-30%) of newly opened flowers. Accordingly, the retention of reward-free and unvisited old flowers increased young flower-pollinator interaction. Our results reveal the importance of a prolonged floral longevity in increasing pollinator attraction toward newly opened receptive flowers without changes in flower colour and form. We conclude that the retention of pollinated, reward-free and unvisited colour-unchanged old flowers in K. regalis is a strategy that counteracts the water use costs associated with the maintenance of large flowers with increased mate opportunities in a pollen-limited scenario.

Epidemiology and outcomes of Clostridium difficile infection in allogeneic hematopoietic cell and lung transplant recipients.

BACKGROUND: Clostridium difficile infection (CDI) is a common complication of lung and allogeneic hematopoietic cell (HCT) transplant, but the epidemiology and outcomes of CDI after transplant are poorly described. METHODS: We performed a prospective, multicenter study of CDI within 365 days post-allogeneic HCT or lung transplantation. Data were collected via patient interviews and medical chart review. Participants were followed weekly in the 12 weeks post-transplant and while hospitalized and contacted monthly up to 18 months post-transplantation. RESULTS: Six sites participated in the study with 614 total participants; 4 enrolled allogeneic HCT (385 participants) and 5 enrolled lung transplant recipients (229 participants). One hundred and fifty CDI cases occurred within 1 year of transplantation; the incidence among lung transplant recipients was 13.1% and among allogeneic HCTs was 31.2%. Median time to CDI was significantly shorter among allogeneic HCT than lung transplant recipients (27 days vs 90 days; P = .037). CDI was associated with significantly higher mortality from 31 to 180 days post-index date among the allogeneic HCT recipients (Hazard ratio [HR] = 1.80; P = .007). There was a trend towards increased mortality among lung transplant recipients from 120 to 180 days post-index date (HR = 4.7, P = .09). CONCLUSIONS: The epidemiology and outcomes of CDI vary by transplant population; surveillance for CDI should continue beyond the immediate post-transplant period.

Voriconazole and squamous cell carcinoma after lung transplantation: A multicenter study.

This study evaluated the independent contribution of voriconazole to the development of squamous cell carcinoma (SCC) in lung transplant recipients, by attempting to account for important confounding factors, particularly immunosuppression. This international, multicenter, retrospective, cohort study included adult patients who underwent lung transplantation during 2005-2008. Cox regression analysis was used to assess the effects of voriconazole and other azoles, analyzed as time-dependent variables, on the risk of developing biopsy-confirmed SCC. Nine hundred lung transplant recipients were included. Median follow-up time from transplantation to end of follow-up was 3.51 years. In a Cox regression model, exposure to voriconazole alone (adjusted hazard ratio 2.39, 95% confidence interval 1.31-4.37) and exposure to voriconazole and other azole(s) (adjusted hazard ratio 3.45, 95% confidence interval 1.07-11.06) were associated with SCC compared with those unexposed after controlling for important confounders including immunosuppressants. Exposure to voriconazole was associated with increased risk of SCC of the skin in lung transplant recipients. Residual confounding could not be ruled out because of the use of proxy variables to control for some confounders. Benefits of voriconazole use when prescribed to lung transplant recipients should be carefully weighed versus the potential risk of SCC. EU PAS registration number: EUPAS5269.

Significant bone loss after stopping long-term denosumab treatment: a post FREEDOM study.

We evaluate 38 elderly women who had received long-term denosumab treatment after stopping the drug. Taking into account the gain during treatment and the loss after stopping treatment, they lost 35.5% of the total gain in the spine, 44.6% of the total gain in the femoral neck, and 103.3% in the total hip. INTRODUCTION: Denosumab (DMAb) is a soluble inhibitor of the receptor activator of nuclear factor-kappaB ligand (RANKL) and, therefore, does not incorporate into the bone matrix. Consistently, DMAb discontinuation is associated with reversal of the effects attained with treatment. PURPOSE: The aim of this study is to assess changes in BMD after a year of discontinuation of DMAb in a group of postmenopausal women treated with DMAb for 7 or 10 years. Secondly, is to evaluate the occurrence of fragility fractures. METHODS: Women who had participated in the FREEDOM study and its extension were invited to participate in this follow-up study. BMD at LS and hip and spine X-rays were obtained. Results were compared to the last value obtained while in treatment to assess changes after discontinuation. RESULTS: Thirty-eight women, mean age: 81 ± 3.4 years completed study procedures; none had received bisphosphonates after stopping DMAb. Mean gap time between DMAb last dose and the follow-up visit was 17 months (range 16-20 months). Bone mineral density (BMD) decreased significantly in all regions: - 8.1% in LS, - 6% in FN, and - 8.4% in TH. Five (5/38, 13.15%) patients had a fragility fracture, one suffered a wrist fracture, and four experienced vertebral fractures. Three patients suffered one vertebral fracture and one of them had two vertebral fractures. Laboratory results showed the following mean values: CTX = 996 ± 307 pg/ml (normal values 550 ± 226 pg/ml); osteocalcin = 55.2 ± 18.6 ng/ml (normal value 42 ng/ml); and 25 OH vitamin D = 23.7 ± 6.9 ng/ml. CONCLUSION: Our results describe the rapid bone loss occurring after cessation of denosumab treatment. Further studies are needed to assess if patients have a higher risk of fracture after stopping DMAb and if so, which patients have the highest risk, and assess the role of transitioning to bisphosphonates in the long term.

Reproductive phenology of Melastomataceae species with contrasting reproductive systems: contemporary and historical drivers.

Flowering and fruiting are key events in the life history of plants, and both are critical to their reproductive success. Besides the role of evolutionary history, plant reproductive phenology is regulated by abiotic factors and shaped by biotic interactions with pollinators and seed dispersers. In Melastomataceae, a dominant Neotropical family, the reproductive systems vary from allogamous with biotic pollination to apomictic, and seed dispersal varies from dry (self-dispersed) to fleshy (animal-dispersed) fruits. Such variety in reproductive strategies is likely to affect flowering and fruiting phenologies. In this study, we described the reproductive phenology of 81 Melastomataceae species occurring in two biodiversity hotspots: the Atlantic rain forest and the campo rupestre. We aim to disentangle the role of abiotic and biotic factors defining flowering and fruiting times of Melastomataceae species, considering the contrasting breeding and seed dispersal systems, and their evolutionary history. In both vegetation types, pollinator-dependent species had higher flowering seasonality than pollinator-independent ones. Flowering patterns presented phylogenetic signal regardless of vegetation type. Fruiting of fleshy-fruited species was seasonal in campo rupestre but not in Atlantic rain forest; the fruiting of dry-fruited species was also not seasonal in both vegetation types. Fruiting showed a low phylogenetic signal, probably because the influence of environment and dispersal agents on fruiting time is stronger than the phylogenetic affinity. Considering these ecophylogenetic patterns, our results indicate that flowering may be shaped by the different reproductive strategies of Melastomataceae lineages, while fruiting patterns may be governed mainly by the seed dispersal strategy and flowering time, with less phylogenetic influence.

Comparison between avian pathogenic (APEC) and avian faecal (AFEC) Escherichia coli isolated from different regions in Brazil.

Detection and analysis of virulence-associated genes (VAGs) of avian pathogenic Escherichia coli (APEC) may be helpful to distinguish pathogenic from commensal faecal strains (AFEC). The aim of this study was to characterise 120 isolates of avian Escherichia coli, comprising 91 APEC (from diseased birds) and 29 AFEC (from healthy chickens), collected in Brazil. Phylogenetic analysis and in vivo pathogenicity testing was performed on 38 VAGs. The VAGs iucD, iutA, iroN, fepC, ompT, cvi and hlyF were statistically associated with medium and high pathogenicity (MP/HP) strains. A minimal group of seven VAGs may be required to accurately discriminate pathogenic and non-pathogenic avian strains of E. coli in Brazil.

Differential Recruitment of Dendritic Cells Subsets to Lymph Nodes Correlates with a Protective or Permissive T-Cell Response during Leishmania (Viannia) Braziliensis or Leishmania (Leishmania) Amazonensis Infection.

Leishmania (L.) amazonensis (La) and L. (V.) braziliensis (Lb) are responsible for a large clinical and immunopathological spectrum in human disease; while La may be responsible for anergic disease, Lb infection leads to cellular hypersensitivity. To better understand the dichotomy in the immune response caused by these Leishmania species, we evaluated subsets of dendritic cells (DCs) and T lymphocyte in draining lymph nodes during the course of La and Lb infection in BALB/c mice. Our results demonstrated a high involvement of DCs in La infection, which was characterized by the greater accumulation of Langerhans cells (LCs); conversely, Lb infection led to an increase in dermal DCs (dDCs) throughout the infection. Considering the T lymphocyte response, an increase of effector, activated, and memory CD4(+) T-cells was observed in Lb infection. Interleukin- (IL-) 4- and IL-10-producing CD4(+)and CD8(+) T-cells were present in both La and Lb infection; however, interferon- (IFN-) γ-producing CD4(+)and CD8(+) T-cells were detected only in Lb infection. The results suggest that during Lb infection, the dDCs were the predominant subset of DCs that in turn was associated with the development of Th1 immune response; in contrast La infection was associated with a preferential accumulation of LCs and total blockage of the development of Th1 immune response.

Mycobacterium bovis hip bursitis in a lung transplant recipient.

We present a report of extrapulmonary Mycobacterium bovis infection in a lung transplant recipient. M. bovis is acquired predominantly by zoonotic transmission, particularly from consumption of unpasteurized foods. We discuss epidemiologic exposure, especially as relates to the Mexico-US border, clinical characteristics, resistance profile, and treatment.

Population structure of Annona crassiflora: an endemic plant species of the Brazilian Cerrado.

Habitat fragmentation has numerous consequences, particularly to endemic species, and has a negative impact on the genetic diversity of neglected species, leading to genetic drift. Annona crassiflora Mart. is a species that is endemic to Brazil, and its incidence in the Cerrado biome has decreased. The identification and characterization of its remaining diversity is necessary for its conservation. Our aim was to study the population structure of A. crassiflora populations from different Cerrado regions in Minas Gerais State, Brazil (Corinto, Curvelo, Carmo da Mata, Boa Esperança, and Paraguaçu) using inter-simple sequence repeat (ISSR) markers and DNA content. Nuclear DNA content was estimated by flow cytometry using 10 individuals from each population. ISSR markers were used for genotyping accessions in order to study their genetic diversity and population structures. We found considerable genetic variation among populations, with the highest variability observed in the Curvelo population. There was a significant positive correlation between DNA content and latitude (r = 0.46, P = 0. 0003). A Bayesian-based cluster analysis grouped the populations into three clusters, which followed their geographical origins. There was some level of genetic diversity and differentiation among the populations, suggesting the need for a conservation plan for this species. The ISSR markers and DNA content analysis were effective in studying the genetic diversity and population structure of A. crassiflora.

Pollen analysis of honey and pollen collected by Apis mellifera linnaeus, 1758 (Hymenoptera, Apidae), in a mixed environment of Eucalyptus plantation and native cerrado in Southeastern Brazil.

Eucalyptus plantations are frequently used for the establishment of bee yards. This study was carried on at Fazenda Brejão, northwestern region of the State of Minas Gerais, Brazil. This farm is covered both with native Cerrado vegetation (Brazilian savanna) and eucalyptus plantations. This paper reports on the botanic origin of pollen pellets and honey collected from honeybee (Apis mellifera) hives along a thirteen-month period (January 2004 to January 2005). The most frequent pollen types found in the pollen pellets during the rainy season were Trema micrantha (Ulmaceae), Copaifera langsdorffii (Fabaceae), an unidentified Poaceae, unidentified Asteraceae-2, Cecropia sp. 1 (Cecropiaceae) and Eucalyptus spp. (Myrtaceae); during the dry season the most frequent pollen types were Acosmium dasycarpum (Fabaceae), Cecropia sp. 1 (Cecropiaceae) and Eucalyptus spp. (Myrtaceae). Pollen grains of Baccharis sp. (Asteraceae), Cecropia sp. 1 (Cecropiaceae), Copaifera langsdorffii (Fabaceae), Mimosa nuda (Fabaceae), Eucalyptus spp. (Myrtaceae) and Trema micrantha (Ulmaceae) were present in the honey samples throughout the study period.