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ABCD. Arquivos Brasileiros de Cirurgia Digestiva     Open Access   (Followers: 4)
ACIMED     Open Access   (SJR: 0.11, h-index: 4)
Acta Amazonica     Open Access   (Followers: 3, SJR: 0.319, h-index: 13)
Acta Bioethica     Open Access   (Followers: 2, SJR: 0.119, h-index: 3)
Acta Bioquimica Clinica Latinoamericana     Open Access   (Followers: 1, SJR: 0.134, h-index: 7)
Acta Botanica Brasilica     Open Access   (Followers: 2, SJR: 0.403, h-index: 17)
Acta botánica mexicana     Open Access   (SJR: 0.212, h-index: 4)
Acta Cirurgica Brasileira     Open Access   (SJR: 0.271, h-index: 14)
Acta Limnologica Brasiliensia     Open Access   (Followers: 1, SJR: 0.204, h-index: 2)
Acta Literaria     Open Access   (Followers: 2, SJR: 0.1, h-index: 2)
Acta Médica Costarricense     Open Access  
Acta Medica Peruana     Open Access   (Followers: 2)
Acta Neurológica Colombiana     Open Access   (Followers: 1)
Acta Odontológica Latinoamericana     Open Access  
Acta Ortopédica Brasileira     Open Access   (Followers: 2, SJR: 0.159, h-index: 9)
Acta Paulista de Enfermagem     Open Access   (Followers: 1, SJR: 0.34, h-index: 12)
Acta Pediátrica Costarricense     Open Access   (Followers: 1)
Acta Scientiarum. Agronomy     Open Access   (Followers: 3, SJR: 0.65, h-index: 11)
Acta Toxicológica Argentina     Open Access  
Acta zoológica mexicana     Open Access  
Actualidades Biológicas     Open Access  
African Human Rights Law J.     Open Access   (Followers: 19)
African Natural History     Open Access   (Followers: 2)
Afro-Asia     Open Access  
Ágora - studies in psychoanalytic theory     Open Access   (Followers: 2, SJR: 0.1, h-index: 1)
Agricultura Tecnica     Open Access   (Followers: 6)
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Agrociencia     Open Access   (Followers: 2, SJR: 0.192, h-index: 13)
Agronomía Mesoamericana     Open Access   (Followers: 1)
Aisthesis     Open Access   (Followers: 1)
Ajayu Órgano de Difusión Científica del Departamento de Psicología UCBSP     Open Access  
Alea : Estudos Neolatinos     Open Access   (Followers: 1, SJR: 0.126, h-index: 2)
Alpha (Osorno)     Open Access  
Ambiente & sociedade     Open Access   (Followers: 2, SJR: 0.189, h-index: 5)
Ambiente Construído     Open Access   (Followers: 2)
América Latina en la historia económica     Open Access   (Followers: 1, SJR: 0.101, h-index: 1)
Anais Brasileiros de Dermatologia     Open Access   (Followers: 1, SJR: 0.456, h-index: 16)
Anais da Academia Brasileira de Ciências     Open Access   (Followers: 2, SJR: 0.344, h-index: 34)
Anais do Museu Paulista : História e Cultura Material     Open Access   (Followers: 1)
Anales de Medicina Interna     Open Access   (Followers: 1)
Anales del Instituto de la Patagonia     Open Access   (Followers: 2)
Anales del Sistema Sanitario de Navarra     Open Access   (Followers: 1, SJR: 0.179, h-index: 15)
Análise Psicológica     Open Access  
Análise Social     Open Access  
Análisis filosófico     Open Access  
Analisis Politico     Open Access   (Followers: 3, SJR: 0.1, h-index: 2)
Andean geology     Open Access   (Followers: 5, SJR: 0.825, h-index: 22)
Angiologia e Cirurgia Vascular     Open Access  
Annali dell'Istituto Superiore di Sanità     Open Access   (SJR: 0.272, h-index: 25)
Anuario Colombiano de Historia Social y de la Cultura     Open Access   (Followers: 1)
Apuntes : Revista de Estudios sobre Patrimonio Cultural - J. of Cultural Heritage Studies     Open Access   (Followers: 4)
Archivos argentinos de pediatría     Open Access  
Archivos de cardiología de México     Open Access   (Followers: 1, SJR: 0.136, h-index: 11)
Archivos de Medicina Veterinaria     Open Access   (Followers: 1, SJR: 0.249, h-index: 13)
Archivos de Neurociencias     Open Access   (Followers: 2, SJR: 0.104, h-index: 4)
Archivos de Pediatria del Uruguay     Open Access   (Followers: 1)
Archivos de Zootecnia     Open Access   (Followers: 4, SJR: 0.231, h-index: 6)
Archivos Españoles de Urología     Open Access   (SJR: 0.228, h-index: 16)
Archivos Venezolanos de Farmacología y Terapéutica     Open Access   (Followers: 1, SJR: 0.102, h-index: 2)
Argos     Open Access   (Followers: 2, SJR: 0.1, h-index: 1)
ARQ     Open Access   (Followers: 5, SJR: 0.1, h-index: 1)
Arquitectura y Urbanismo     Open Access   (Followers: 1)
Arquivo Brasileiro de Medicina Veterinária e Zootecnia     Open Access   (Followers: 1, SJR: 0.292, h-index: 18)
Arquivos Brasileiros de Cardiologia     Open Access   (Followers: 1, SJR: 0.33, h-index: 29)
Arquivos Brasileiros de Endocrinologia e Metabologia     Open Access   (SJR: 0.329, h-index: 26)
Arquivos Brasileiros de Oftalmologia     Open Access   (SJR: 0.298, h-index: 15)
Arquivos de Gastroenterologia     Open Access   (Followers: 1, SJR: 0.43, h-index: 18)
Arquivos de Medicina     Open Access  
Arquivos de Neuro-Psiquiatria     Open Access   (SJR: 0.357, h-index: 33)
Arquivos do Instituto Biológico     Open Access  
Arquivos Internacionais de Otorrinolaringologia     Open Access  
ARS     Open Access   (Followers: 1)
Atenea (Concepción)     Open Access   (Followers: 1, SJR: 0.1, h-index: 2)
Atmósfera     Open Access   (SJR: 0.346, h-index: 13)
Audiology - Communication Research     Open Access   (Followers: 5)
Avaliação : Revista da Avaliação da Educação Superior (Campinas)     Open Access  
Avances en Odontoestomatologia     Open Access   (SJR: 0.112, h-index: 4)
Avances en Periodoncia e Implantología Oral     Open Access   (Followers: 5)
Bakhtiniana : Revista de Estudos do Discurso     Open Access  
BAR. Brazilian Administration Review     Open Access   (Followers: 1, SJR: 0.165, h-index: 4)
Biocell     Open Access   (SJR: 0.228, h-index: 19)
Biota Neotropica     Open Access   (SJR: 0.437, h-index: 12)
Biotecnología Aplicada     Open Access  
Boletim de Ciências Geodésicas     Open Access   (SJR: 0.202, h-index: 4)
Boletim do Museu Paraense Emílio Goeldi. Ciências Humanas     Open Access   (Followers: 1, SJR: 0.201, h-index: 2)
Boletin Chileno de Parasitologia     Open Access  
Boletín de Filología     Open Access  
Boletín de Historia Argentina y Americana Dr. Emilio Ravignani     Open Access   (Followers: 1)
Boletin de la Sociedad Argentina de Botanica     Open Access   (Followers: 1, SJR: 0.191, h-index: 3)
Boletín de la Sociedad Botánica de México     Open Access  
Boletin de la Sociedad Chilena de Quimica     Open Access  
Boletín de la Sociedad Geológica Mexicana     Open Access   (SJR: 0.206, h-index: 7)
Boletín del Museo Chileno de Arte Precolombino     Open Access   (Followers: 1)
Bosque     Open Access   (Followers: 1, SJR: 0.245, h-index: 7)
Bragantia     Open Access   (Followers: 2, SJR: 0.685, h-index: 18)
Brazilian Archives of Biology and Technology     Open Access   (Followers: 2, SJR: 0.237, h-index: 24)
Brazilian Dental J.     Open Access   (Followers: 2, SJR: 0.433, h-index: 28)
Brazilian J. of Biology     Open Access   (Followers: 3, SJR: 0.436, h-index: 30)
Brazilian J. of Chemical Engineering     Open Access   (Followers: 3, SJR: 0.437, h-index: 25)
Brazilian J. of Food Technology     Open Access   (Followers: 4)

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Journal Cover   Brazilian Journal of Medical and Biological Research
  [SJR: 0.431]   [H-I: 62]   [0 followers]  Follow
  This is an Open Access Journal Open Access journal
   ISSN (Print) 0100-879X - ISSN (Online) 1414-431X
   Published by SciELO Homepage  [789 journals]
  • Plasticity of neutrophils reveals modulatory capacity

    • Abstract: Neutrophils are widely known as proinflammatory cells associated with tissue damage and for their early arrival at sites of infection, where they exert their phagocytic activity, release their granule contents, and subsequently die. However, this view has been challenged by emerging evidence that neutrophils have other activities and are not so short-lived. Following activation, neutrophil effector functions include production and release of granule contents, reactive oxygen species (ROS), and neutrophil extracellular traps (NETs). Neutrophils have also been shown to produce a wide range of cytokines that have pro- or anti-inflammatory activity, adding a modulatory role for this cell, previously known as a suicide effector. The presence of cytokines almost always implies intercellular modulation, potentially unmasking interactions of neutrophils with other immune cells. In fact, neutrophils have been found to help B cells and to modulate dendritic cell (DC), macrophage, and T-cell activities. In this review, we describe some ways in which neutrophils influence the inflammatory environment in infection, cancer, and autoimmunity, regulating both innate and adaptive immune responses. These cells can switch phenotypes and exert functions beyond cytotoxicity against invading pathogens, extending the view of neutrophils beyond suicide effectors to include functions as regulatory and suppressor cells.
  • Gender, race and socioeconomic influence on diagnosis and treatment of
           thyroid disorders in the Brazilian Longitudinal Study of Adult Health

    • Abstract: Thyroid diseases are common, and use of levothyroxine is increasing worldwide. We investigated the influence of gender, race and socioeconomic status on the diagnosis and treatment of thyroid disorders using data from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil), a multicenter cohort study of civil servants (35-74 years of age) from six Brazilian cities. Diagnosis of thyroid dysfunction was by thyrotropin (TSH), and free thyroxine (FT4) if TSH was altered, and the use of specific medications. Multivariate logistic regression models were constructed using overt hyperthyroidism/hypothyroidism and levothyroxine use as dependent variables and sociodemographic characteristics as independent variables. The frequencies of overt hyper- and hypothyroidism were 0.7 and 7.4%, respectively. Using whites as the reference ethnicity, brown, and black race were protective for overt hypothyroidism (OR=0.76, 95%CI=0.64-0.89, and OR=0.53, 95%CI=0.43-0.67, respectively, and black race was associated with overt hyperthyroidism (OR=1.82, 95%CI=1.06-3.11). Frequency of hypothyroidism treatment was higher in women, browns, highly educated participants and those with high net family incomes. After multivariate adjustment, levothyroxine use was associated with female gender (OR=6.06, 95%CI=3.19-11.49) and high net family income (OR=3.23, 95%CI=1.02-10.23). Frequency of hyperthyroidism treatment was higher in older than in younger individuals. Sociodemographic factors strongly influenced the diagnosis and treatment of thyroid disorders, including the use of levothyroxine.
  • Role of a GenoType MTBDRplus line probe assay in early detection
           of multidrug-resistant tuberculosis at a Brazilian reference center

    • Abstract: Resistance to Mycobacterium tuberculosis is a reality worldwide, and its diagnosis continues to be difficult and time consuming. To face this challenge, the World Health Organization has recommended the use of rapid molecular tests. We evaluated the routine use (once a week) of a line probe assay (Genotype MTBDRplus) for early diagnosis of resistance and for assessment of the main related risk factors over 2 years. A total of 170 samples were tested: 15 (8.8%) were resistant, and multidrug resistance was detected in 10 (5.9%). The sensitivity profile took 3 weeks (2 weeks for culture and 1 week for rapid testing). Previous treatment for tuberculosis and the persistence of positive acid-fast smears after 4 months of supervised treatment were the major risk factors observed. The use of molecular tests enabled early diagnosis of drug-resistant bacilli and led to appropriate treatment of the disease. This information has the potential to interrupt the transmission chain of resistant M. tuberculosis.
  • Relationship between salt consumption measured by 24-h urine collection
           and blood pressure in the adult population of Vitória (Brazil)

    • Abstract: High salt intake is related to an increase in blood pressure and development of hypertension. However, currently, there are no national representative data in Brazil using the gold standard method of 24-h urine collection to measure sodium consumption. This study aimed to determine salt intake based on 24-h urine collection in a sample of 272 adults of both genders and to correlate it with blood pressure levels. We used a rigorous protocol to assure an empty bladder prior to initiating urine collection. We excluded subjects with a urine volume <500 mL, collection period outside of an interval of 23-25 h, and subjects with creatinine excretion that was not within the range of 14.4-33.6 mg/kg (men) and 10.8-25.2 mg/kg (women). The mean salt intake was 10.4±4.1 g/day (d), and 94% of the participants (98% of men and 90% of women) ingested more than the recommended level of 5 g/d. We found a positive association between salt and body mass index (BMI) categories, as well as with salt and blood pressure, independent of age and BMI. The difference in systolic blood pressure reached 13 mmHg between subjects consuming less than 6 g/d of salt and those ingesting more than 18 g/d. Subjects with hypertension had a higher estimated salt intake than normotensive subjects (11.4±5.0 vs 9.8±3.6 g/d, P<0.01), regardless of whether they were under treatment. Our data indicate the need for interventions to reduce sodium intake, as well the need for ongoing, appropriate monitoring of salt consumption in the general population.
  • Changes in circulating endothelial progenitor cells predict responses of
           multiple myeloma patients to treatment with bortezomib and dexamethasone

    • Abstract: Four cycles of chemotherapy are required to assess responses of multiple myeloma (MM) patients. We investigated whether circulating endothelial progenitor cells (cEPCs) could be a biomarker for predicting patient response in the first cycle of chemotherapy with bortezomib and dexamethasone, so patients might avoid ineffective and costly treatments and reduce exposure to unwanted side effects. We measured cEPCs and stromal cell-derived factor-1α (SDF-1α) in 46 MM patients in the first cycle of treatment with bortezomib and dexamethasone, and investigated clinical relevance based on patient response after four 21-day cycles. The mononuclear cell fraction was analyzed for cEPC by FACS analysis, and SDF-1α was analyzed by ELISA. The study population was divided into 3 groups according to the response to chemotherapy: good responders (n=16), common responders (n=12), and non-responders (n=18). There were no significant differences among these groups at baseline day 1 (P>0.05). cEPC levels decreased slightly at day 21 (8.2±3.3 cEPCs/μL) vs day 1 (8.4±2.9 cEPCs/μL) in good responders (P>0.05). In contrast, cEPC levels increased significantly in the other two groups (P<0.05). SDF-1α changes were closely related to changes in cEPCs. These findings indicate that change in cEPCs at day 21 in the first cycle might be considered a noninvasive biomarker for predicting a later response, and extent of change could help decide whether to continue this costly chemotherapy. cEPCs and the SDF-1α/CXCR4 axis are potential therapeutic targets for improved response and outcomes in MM patients.
  • Comparative efficacy and safety of the left versus right radial approach
           for percutaneous coronary procedures: a meta-analysis including 6870

    • Abstract: The radial approach is widely used in the treatment of patients with coronary artery disease. We conducted a meta-analysis of published results on the efficacy and safety of the left and right radial approaches in patients undergoing percutaneous coronary procedures. A systematic search of reference databases was conducted, and data from 14 randomized controlled trials involving 6870 participants were analyzed. The left radial approach was associated with significant reductions in fluoroscopy time [standardized mean difference (SMD)=-0.14, 95% confidence interval (CI)=-0.19 to -0.09; P<0.00001] and contrast volume (SMD=-0.07, 95%CI=-0.12 to -0.02; P=0.009). There were no significant differences in rate of procedural failure of the left and the right radial approaches [risk ratios (RR)=0.98; 95%CI=0.77-1.25; P=0.88] or procedural time (SMD=-0.05, 95%CI=0.17-0.06; P=0.38). Tortuosity of the subclavian artery (RR=0.27, 95%CI=0.14-0.50; P<0.0001) was reported more frequently with the right radial approach. A greater number of catheters were used with the left than with the right radial approach (SMD=0.25, 95%CI=0.04-0.46; P=0.02). We conclude that the left radial approach is as safe as the right radial approach, and that the left radial approach should be recommended for use in percutaneous coronary procedures, especially in percutaneous coronary angiograms.
  • Decreased brain-derived neurotrophic factor plasma levels in psoriasis

    • Abstract: Brain-derived neurotrophic factor (BDNF) is associated with neuroplasticity and synaptic strength, and is decreased in conditions associated with chronic stress. Nevertheless, BDNF has not yet been investigated in psoriasis, a chronic inflammatory systemic disease that is exacerbated by stress. Therefore, our aim was to determine BDNF plasma levels in psoriasis patients and healthy controls. Adult patients (n=94) presenting with psoriasis for at least 1 year were enrolled, and age- and gender-matched with healthy controls (n=307) from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil). Participants had neither a previous history of coronary artery disease nor current episode of major depression. BDNF plasma levels were determined using the Promega ELISA kit. A general linear model was used to compare BDNF levels in psoriasis patients and controls, with age, gender, systolic blood pressure, serum fasting glucose, blood lipid levels, triglycerides, smoking status, and body mass index examined. After adjusting for clinical and demographic variables, significantly decreased BNDF plasma levels were observed in psoriasis patients (P=0.01) (estimated marginal means of 3922 pg/mL; 95%CI=2660-5135) compared with controls (5788 pg/mL; 95%CI=5185-6442). Similar BDNF levels were found in both mild and severe cases of psoriasis. Our finding, that BDNF is decreased in psoriasis, supports the concept of a brain-skin connection in psoriasis. Further studies should determine if BDNF is increased after specific psoriasis treatments, and associated with different disease stages.
  • Association of body mass index with disease severity and prognosis in
           patients with non-cystic fibrosis bronchiectasis

    • Abstract: The objective of this observational, multicenter study was to evaluate the association of body mass index (BMI) with disease severity and prognosis in patients with non-cystic fibrosis bronchiectasis. A total of 339 patients (197 females, 142 males) diagnosed with non-cystic fibrosis bronchiectasis by high-resolution computed tomography were classified into four groups: underweight (BMI<18.5 kg/m2), normal weight (18.5≤BMI<25.0 kg/m2), overweight (25.0≤BMI<30.0 kg/m2), and obese (BMI≥30.0 kg/m2). Clinical variables expressing disease severity were recorded, and acute exacerbations, hospitalizations, and survival rates were estimated during the follow-up period. The mean BMI was 21.90 kg/m2. The underweight group comprised 28.61% of all patients. BMI was negatively correlated with acute exacerbations, C-reactive protein, erythrocyte sedimentation rate, radiographic extent of bronchiectasis, and chronic colonization by P. aeruginosa and positively correlated with pulmonary function indices. BMI was a significant predictor of hospitalization risk independent of relevant covariates. The 1-, 2-, 3-, and 4-year cumulative survival rates were 94%, 86%, 81%, and 73%, respectively. Survival rates decreased with decreasing BMI (χ2=35.16, P<0.001). The arterial carbon dioxide partial pressure, inspiratory capacity, age, BMI, and predicted percentage of forced expiratory volume in 1 s independently predicted survival in the Cox proportional hazard model. In conclusion, an underweight status was highly prevalent among patients with non-cystic fibrosis bronchiectasis. Patients with a lower BMI were prone to developing more acute exacerbations, worse pulmonary function, amplified systemic inflammation, and chronic colonization by P. aeruginosa. BMI was a major determinant of hospitalization and death risks. BMI should be considered in the routine assessment of patients with non-cystic fibrosis bronchiectasis.
  • Transtracheal puncture: a forgotten procedure

    • Abstract: Transtracheal puncture has long been known as a safe, low-cost procedure. However, with the advent of bronchoscopy, it has largely been forgotten. Two researchers have suggested the use of α-amylase activity to diagnose salivary aspiration, but the normal values of this enzyme in tracheobronchial secretions are unknown. We aimed to define the normal values of α-amylase activity in tracheobronchial secretions and verify the rate of major complications of transtracheal puncture. From October 2009 to June 2011, we prospectively evaluated 118 patients without clinical or radiological signs of salivary aspiration who underwent transtracheal puncture before bronchoscopy. The patients were sedated with a solution of lidocaine and diazepam until they reached a Ramsay sedation score of 2 or 3. We then cleaned the cervical region and anesthetized the superficial planes with lidocaine. Next, we injected 10 mL of 2% lidocaine into the tracheobronchial tree. Finally, we injected 10 mL of normal saline into the tracheobronchial tree and immediately aspirated the saline with maximum vacuum pressure to collect samples for measurement of the α-amylase level. The α-amylase level mean ± SE, median, and range were 1914 ± 240, 1056, and 24-10,000 IU/L, respectively. No major complications (peripheral desaturation, subcutaneous emphysema, cardiac arrhythmia, or hemoptysis) occurred among 118 patients who underwent this procedure. Transtracheal aspiration is a safe, low-cost procedure. We herein define for the first time the normal α-amylase levels in the tracheobronchial secretions of humans.
  • Essential oil of Lippia alba and its main constituent citral
           block the excitability of rat sciatic nerves

    • Abstract: Lippia alba is empirically used for infusions, teas, macerates, and hydroalcoholic extracts because of its antispasmodic, analgesic, sedative, and anxiolytic effects. Citral is a mixture of trans-geranial and cis-neral and is the main constituent of L. alba essential oil and possesses analgesic, anxiolytic, anticonvulsant, and sedative effects. The present study evaluated the effects of the essential oil of L. alba (EOLa) and citral on compound action potentials (CAPs) in Wistar rat sciatic nerves. Both drugs inhibited CAP in a concentration-dependent manner. The calculated half-maximal inhibitory concentrations (IC50) of peak-to-peak amplitude were 53.2 µg/mL and 35.00 µg/mL (or 230 µM) for EOLa and citral, respectively. Peak-to-peak amplitude of the CAP was significantly reduced by 30 µg/mL EOLa and 10 µg/mL citral. EOLa and citral (at 60 and 30 µg/mL, values close to their respective IC50 for CAP blockade) significantly increased chronaxy and rheobase. The conduction velocity of the first and second CAP components was statistically reduced to ∼86% of control with 10 µg/mL EOLa and ∼90% of control with 3 µg/mL citral. This study showed that EOLa inhibited nerve excitability and this effect can be explained by the presence of citral in its composition. Both EOLa and citral showed inhibitory actions at lower concentrations compared with other essential oils and constituents with local anesthetic activity. In conclusion, these data demonstrate that EOLa and citral are promising agents in the development of new drugs with local anesthetic activity.
  • Changes in expression of BDNF and its receptors TrkB and p75NTR in the
           hippocampus of a dog model of chronic alcoholism and abstinence

    • Abstract: Chronic ethanol consumption can produce learning and memory deficits. Brain-derived neurotrophic factor (BDNF) and its receptors affect the pathogenesis of alcoholism. In this study, we examined the expression of BDNF, tropomyosin receptor kinase B (TrkB) and p75 neurotrophin receptor (p75NTR) in the hippocampus of a dog model of chronic alcoholism and abstinence. Twenty domestic dogs (9-10 months old, 15-20 kg; 10 males and 10 females) were obtained from Harbin Medical University. A stable alcoholism model was established through ad libitum feeding, and anti-alcohol drug treatment (Zhong Yao Jie Jiu Ling, the main ingredient was the stems of watermelon; developed in our laboratory), at low- and high-doses, was carried out. The Zhong Yao Jie Jiu Ling was effective for the alcoholism in dogs. The morphology of hippocampal neurons was evaluated using hematoxylin-eosin staining. The number and morphological features of BDNF, TrkB and p75NTR-positive neurons in the dentate gyrus (DG), and the CA1, CA3 and CA4 regions of the hippocampus were observed using immunohistochemistry. One-way ANOVA was used to determine differences in BDNF, TrkB and p75NTR expression. BDNF, TrkB and p75NTR-positive cells were mainly localized in the granular cell layer of the DG and in the pyramidal cell layer of the CA1, CA3 and CA4 regions (DG>CA1>CA3>CA4). Expression levels of both BDNF and TrkB were decreased in chronic alcoholism, and increased after abstinence. The CA4 region appeared to show the greatest differences. Changes in p75NTR expression were the opposite of those of BDNF and TrkB, with the greatest differences observed in the DG and CA4 regions.
  • Rat visceral yolk sac cells: viability and expression of cell markers
           during maternal diabetes

    • Abstract: The function of the visceral yolk sac (VYS) is critical for embryo organogenesis until final fetal development in rats, and can be affected by conditions such as diabetes. In view of the importance of diabetes during pregnancy for maternal and neonatal health, the objective of this study was to assess fetal weight, VYS cell markers, and viability in female Wistar rats (200-250 g) with induced diabetes (alloxan, 37 mg/kg) on the 8th gestational day (gd 8). At gd 15, rats from control (n=5) and diabetic (n=5) groups were anesthetized and laparotomized to remove the uterine horns for weighing of fetuses and collecting the VYS. Flow cytometry was used for characterizing VYS cells, and for determining mitochondrial activity, cell proliferation, DNA ploidy, cell cycle phases, and caspase-3 activity. Fetal weight was reduced in the diabetic group. Expression of the cell markers CD34, VEGFR1, CD115, CD117, CD14, CCR2, CD90, CD44, STRO-1, OCT3/4, and Nanog was detected in VYS cells in both groups. In the diabetic group, significantly decreased expression of CD34 (P<0.05), CCR2 (P<0.001), and OCT3/4 (P<0.01), and significantly increased expression of CD90 (P<0.05), CD117 (P<0.01), and CD14 (P<0.05) were observed. VYS cells with inactive mitochondria, activated caspase-3, and low proliferation were present in the rats with diabetes. Severe hyperglycemia caused by maternal diabetes had negative effects on pregnancy, VYS cell viability, and the expression of cell markers.
  • Effect of point mutations on Herbaspirillum seropedicae NifA

    • Abstract: NifA is the transcriptional activator of the nif genes in Proteobacteria. It is usually regulated by nitrogen and oxygen, allowing biological nitrogen fixation to occur under appropriate conditions. NifA proteins have a typical three-domain structure, including a regulatory N-terminal GAF domain, which is involved in control by fixed nitrogen and not strictly required for activity, a catalytic AAA+ central domain, which catalyzes open complex formation, and a C-terminal domain involved in DNA-binding. In Herbaspirillum seropedicae, a β-proteobacterium capable of colonizing Graminae of agricultural importance, NifA regulation by ammonium involves its N-terminal GAF domain and the signal transduction protein GlnK. When the GAF domain is removed, the protein can still activate nif genes transcription; however, ammonium regulation is lost. In this work, we generated eight constructs resulting in point mutations in H. seropedicae NifA and analyzed their effect on nifH transcription in Escherichia coli and H. seropedicae. Mutations K22V, T160E, M161V, L172R, and A215D resulted in inactive proteins. Mutations Q216I and S220I produced partially active proteins with activity control similar to wild-type NifA. However, mutation G25E, located in the GAF domain, resulted in an active protein that did not require GlnK for activity and was partially sensitive to ammonium. This suggested that G25E may affect the negative interaction between the N-terminal GAF domain and the catalytic central domain under high ammonium concentrations, thus rendering the protein constitutively active, or that G25E could lead to a conformational change comparable with that when GlnK interacts with the GAF domain.
  • Methylmercury inhibits prolactin release in a cell line of pituitary

    • Abstract: Heavy metals, such as methylmercury, are key environmental pollutants that easily reach human beings by bioaccumulation through the food chain. Several reports have demonstrated that endocrine organs, and especially the pituitary gland, are potential targets for mercury accumulation; however, the effects on the regulation of hormonal release are unclear. It has been suggested that serum prolactin could represent a biomarker of heavy metal exposure. The aim of this study was to evaluate the effect of methylmercury on prolactin release and the role of the nitrergic system using prolactin secretory cells (the mammosomatotroph cell line, GH3B6). Exposure to methylmercury (0-100 μM) was cytotoxic in a time- and concentration-dependent manner, with an LC50 higher than described for cells of neuronal origin, suggesting GH3B6 cells have a relative resistance. Methylmercury (at exposures as low as 1 μM for 2 h) also decreased prolactin release. Interestingly, inhibition of nitric oxide synthase by N-nitro-L-arginine completely prevented the decrease in prolactin release without acute neurotoxic effects of methylmercury. These data indicate that the decrease in prolactin production occurs via activation of the nitrergic system and is an early effect of methylmercury in cells of pituitary origin.
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