16 results on '"Gonçalves C"'
Search Results
2. Longitudinal change in physical activity and adiposity in the transition from adolescence to early adulthood: the 1993 Pelotas cohort study
- Author
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Kwon, Soyang, Menezes, Ana M. B., Ekelund, Ulf, Wehrmeister, Fernando C., Gonçalves, Helen, da Silva, Bruna Gonçalves C., and Janz, Kathleen F.
- Published
- 2022
- Full Text
- View/download PDF
3. Prevalence and associated factors of supine sleep position in 3-month-old infants: findings from the 2015 Pelotas (Brazil) Birth Cohort
- Author
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da Silva, Bruna Gonçalves C., da Silveira, Mariângela Freitas, de Oliveira, Paula Duarte, Domingues, Marlos Rodrigues, Neumann, Nelson Arns, Barros, Fernando C., and Bertoldi, Andréa Dâmaso
- Published
- 2019
- Full Text
- View/download PDF
4. Screen-based sedentary behavior during adolescence and pulmonary function in a birth cohort.
- Author
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Gonçalves C. da Silva, Bruna, Menezes, Ana M. B., Wehrmeister, Fernando C., Barros, Fernando C., and Pratt, Michael
- Subjects
- *
LUNG physiology , *COMPUTERS , *CONFIDENCE intervals , *LONGITUDINAL method , *PROBABILITY theory , *REGRESSION analysis , *RESPIRATORY measurements , *PULMONARY function tests , *SELF-evaluation , *SEX distribution , *SPIROMETRY , *TELEVISION , *VIDEO games , *VITAL capacity (Respiration) , *SEDENTARY lifestyles , *DESCRIPTIVE statistics , *ADOLESCENCE - Abstract
Background: Adolescents spend many hours in sitting activities as television viewing, video game playing and computer use. The relationship between sedentary behavior and respiratory health remains poorly elucidated. To date there have been no studies evaluating the relationship between sedentary behavior and pulmonary function in young populations. The purpose of this study is to examine the association between the trajectory of screen-based sedentary behavior from 11 to 18 years and pulmonary function at 18 years in a Brazilian birth cohort. Methods: Data from a longitudinal prospective study conducted among the participants of the 1993 Pelotas (Brazil) Birth Cohort. Time spent on television, video games, and computers during a weekday was self-reported at ages 11, 15 and 18 years. For each age, sedentary behavior was defined as the sum of time spent on these screen-based activities. To evaluate the sedentary behavior trajectory during adolescence group-based trajectory modeling was used. Outcome variables were three pulmonary function parameters: forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF), evaluated by spirometry, at 18 years expressed as z-scores. Crude and adjusted linear regressions, stratified by sex, were performed. Results: The three-group trajectory of sedentary behavior was the best fitting model. The trajectory groups were: always high (representing 38.8% of the individuals), always moderate (54.1%), and always low (7.1%). In the adjusted analyses, boys in the always-low group for sedentary behavior had higher FVC at 18 years (β = 0.177; 95% CI:0.027;0. 327; p = 0.021) than boys in the always-high group. There were no differences for other pulmonary function parameters in boys. No significant association was found for girls. Conclusion: The trajectory of screen-based sedentary behavior throughout adolescence was not consistent associated with pulmonary function at 18 years. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
5. Pre-eclampsia in the intensive care unit: indicators of severity and hospital outcome
- Author
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Gouveia, I, Costa, C, Cunha, P, Bártolo, A, Milheiro, R, Gonçalves, C, Carvalho, A, Cardoso, T, Martins, S, and Magalhães, J
- Subjects
Poster Presentation - Published
- 2005
6. Zinc treatment ameliorates diarrhea and intestinal inflammation in undernourished rats.
- Author
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de Queiroz, Camila A. A., Fonseca, Said Gonçalves C., Frota, Priscila B., Figueiredo, Ítalo L., Aragão, Karoline S., Magalhães, Carlos Emanuel C., de Carvalho, Cibele B. M., Lima, Aldo Ângelo M., Ribeiro, Ronaldo A., Guerrant, Richard L., Moore, Sean R., and Oriá, Reinaldo B.
- Abstract
Background: WHO guidelines recommend zinc supplementation as a key adjunct therapy for childhood diarrhea in developing countries, however zinc’s anti-diarrheal effects remain only partially understood. Recently, it has been recognized that low-grade inflammation may influence stunting. In this study, we examined whether oral zinc supplementation could improve weight, intestinal inflammation, and diarrhea in undernourished weanling rats. Methods: Rats were undernourished using a northeastern Brazil regional diet (RBD) for two weeks, followed by oral gavage with a saturated lactose solution (30 g/kg) in the last 7 days to induce osmotic diarrhea. Animals were checked for diarrhea daily after lactose intake. Blood was drawn in order to measure serum zinc levels by atomic absorption spectroscopy. Rats were euthanized to harvest jejunal tissue for histology and cytokine profiles by ELISA. In a subset of animals, spleen samples were harvested under aseptic conditions to quantify bacterial translocation. Results: Oral zinc supplementation increased serum zinc levels following lactose-induced osmotic diarrhea. In undernourished rats, zinc improved weight gain following osmotic diarrhea and significantly reduced diarrheal scores by the third day of lactose intake (p < 0.05), with improved jejunum histology (p < 0.0001). Zinc supplementation diminished bacterial translocation only in lactose-challenged undernourished rats (p = 0.03) compared with the untreated challenged controls and reduced intestinal IL-1β and TNF-α cytokines to control levels. Conclusion: Altogether our findings provide novel mechanisms of zinc action in the setting of diarrhea and undernutrition and support the use of zinc to prevent the vicious cycle of malnutrition and diarrhea. [ABSTRACT FROM AUTHOR]
- Published
- 2014
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- View/download PDF
7. Extensive remodeling of sugar metabolism through gene loss and horizontal gene transfer in a eukaryotic lineage.
- Author
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Pontes A, Paraíso F, Silva M, Lagoas C, Aires A, Brito PH, Rosa CA, Lachance MA, Sampaio JP, Gonçalves C, and Gonçalves P
- Subjects
- Phylogeny, Carbohydrate Metabolism genetics, Sugars metabolism, Evolution, Molecular, Genome, Fungal, Gene Transfer, Horizontal
- Abstract
Background: In yeasts belonging to the subphylum Saccharomycotina, genes encoding components of the main metabolic pathways, like alcoholic fermentation, are usually conserved. However, in fructophilic species belonging to the floral Wickerhamiella and Starmerella genera (W/S clade), alcoholic fermentation was uniquely shaped by events of gene loss and horizontal gene transfer (HGT)., Results: Because HGT and gene losses were first identified when only eight W/S-clade genomes were available, we collected publicly available genome data and sequenced the genomes of 36 additional species. A total of 63 genomes, representing most of the species described in the clade, were included in the analyses. Firstly, we inferred the phylogenomic tree of the clade and inspected the genomes for the presence of HGT-derived genes involved in fructophily and alcoholic fermentation. We predicted nine independent HGT events and several instances of secondary loss pertaining to both pathways. To investigate the possible links between gene loss and acquisition events and evolution of sugar metabolism, we conducted phenotypic characterization of 42 W/S-clade species including estimates of sugar consumption rates and fermentation byproduct formation. In some instances, the reconciliation of genotypes and phenotypes yielded unexpected results, such as the discovery of fructophily in the absence of the cornerstone gene (FFZ1) and robust alcoholic fermentation in the absence of the respective canonical pathway., Conclusions: These observations suggest that reinstatement of alcoholic fermentation in the W/S clade triggered a surge of innovation that goes beyond the utilization of xenologous enzymes, with fructose metabolism playing a key role., (© 2024. The Author(s).)
- Published
- 2024
- Full Text
- View/download PDF
8. Screen-based sedentary behavior during adolescence and pulmonary function in a birth cohort.
- Author
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da Silva BGC, Menezes AMB, Wehrmeister FC, Barros FC, and Pratt M
- Subjects
- Adolescent, Brazil, Child, Exercise, Female, Forced Expiratory Volume, Humans, Linear Models, Male, Peak Expiratory Flow Rate, Prospective Studies, Self Report, Sex Factors, Spirometry, Vital Capacity, Computers, Lung physiology, Sedentary Behavior, Television, Video Games
- Abstract
Background: Adolescents spend many hours in sitting activities as television viewing, video game playing and computer use. The relationship between sedentary behavior and respiratory health remains poorly elucidated. To date there have been no studies evaluating the relationship between sedentary behavior and pulmonary function in young populations. The purpose of this study is to examine the association between the trajectory of screen-based sedentary behavior from 11 to 18 years and pulmonary function at 18 years in a Brazilian birth cohort., Methods: Data from a longitudinal prospective study conducted among the participants of the 1993 Pelotas (Brazil) Birth Cohort. Time spent on television, video games, and computers during a weekday was self-reported at ages 11, 15 and 18 years. For each age, sedentary behavior was defined as the sum of time spent on these screen-based activities. To evaluate the sedentary behavior trajectory during adolescence group-based trajectory modeling was used. Outcome variables were three pulmonary function parameters: forced expiratory volume in one second (FEV
1 ), forced vital capacity (FVC), and peak expiratory flow (PEF), evaluated by spirometry, at 18 years expressed as z-scores. Crude and adjusted linear regressions, stratified by sex, were performed., Results: The three-group trajectory of sedentary behavior was the best fitting model. The trajectory groups were: always high (representing 38.8% of the individuals), always moderate (54.1%), and always low (7.1%). In the adjusted analyses, boys in the always-low group for sedentary behavior had higher FVC at 18 years (β = 0.177; 95% CI:0.027;0.327; p = 0.021) than boys in the always-high group. There were no differences for other pulmonary function parameters in boys. No significant association was found for girls., Conclusion: The trajectory of screen-based sedentary behavior throughout adolescence was not consistent associated with pulmonary function at 18 years.- Published
- 2017
- Full Text
- View/download PDF
9. Increased red cell distribution width in Fanconi anemia: a novel marker of stress erythropoiesis.
- Author
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Sousa R, Gonçalves C, Guerra IC, Costa E, Fernandes A, do Bom Sucesso M, Azevedo J, Rodriguez A, Rius R, Seabra C, Ferreira F, Ribeiro L, Ferrão A, Castedo S, Cleto E, Coutinho J, Carvalho F, Barbot J, and Porto B
- Subjects
- Adolescent, Child, Child, Preschool, Cytogenetics, Erythrocytes physiology, Erythropoiesis genetics, Fanconi Anemia physiopathology, Female, Humans, Male, Oxidative Stress genetics, Oxidative Stress physiology, Biomarkers metabolism, Erythrocytes metabolism, Erythropoiesis physiology, Fanconi Anemia pathology
- Abstract
Background: Red cell distribution width (RDW), a classical parameter used in the differential diagnosis of anemia, has recently been recognized as a marker of chronic inflammation and high levels of oxidative stress (OS). Fanconi anemia (FA) is a genetic disorder associated to redox imbalance and dysfunctional response to OS. Clinically, it is characterized by progressive bone marrow failure, which remains the primary cause of morbidity and mortality. Macrocytosis and increased fetal hemoglobin, two indicators of bone marrow stress erythropoiesis, are generally the first hematological manifestations to appear in FA. However, the significance of RDW and its possible relation to stress erythropoiesis have never been explored in FA. In the present study we analyzed routine complete blood counts from 34 FA patients and evaluated RDW, correlating with the hematological parameters most consistently associated with the FA phenotype., Results: We showed, for the first time, that RDW is significantly increased in FA. We also showed that increased RDW is correlated with thrombocytopenia, neutropenia and, most importantly, highly correlated with anemia. Analyzing sequential hemograms from 3 FA patients with different clinical outcomes, during 10 years follow-up, we confirmed a consistent association between increased RDW and decreased hemoglobin, which supports the postulated importance of RDW in the evaluation of hematological disease progression., Conclusions: This study shows, for the first time, that RDW is significantly increased in FA, and this increment is correlated with neutropenia, thrombocytopenia, and highly correlated with anemia. According to the present results, it is suggested that increased RDW can be a novel marker of stress erythropoiesis in FA.
- Published
- 2016
- Full Text
- View/download PDF
10. Quantitative trait locus analysis of parasite density reveals that HbS gene carriage protects severe malaria patients against Plasmodium falciparum hyperparasitaemia.
- Author
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do Sambo MR, Penha-Gonçalves C, Trovoada MJ, Costa J, Lardoeyt R, and Coutinho A
- Subjects
- Adolescent, Anemia parasitology, Anemia pathology, Angola, Animals, Case-Control Studies, Child, Child, Preschool, Disease Resistance, Female, Humans, Infant, Malaria, Cerebral parasitology, Malaria, Cerebral pathology, Malaria, Falciparum pathology, Male, Hemoglobin, Sickle genetics, Malaria, Falciparum genetics, Malaria, Falciparum parasitology, Parasitemia genetics, Quantitative Trait Loci
- Abstract
Background: Haemoglobin S (HbS) is the gene known to confer the strongest advantage against malaria morbidity and mortality. Multiple HbS effects have been described resulting in protection against parasitaemia and reduction of severe malaria risk. This study aimed to explore HbS protection against severe malaria and Plasmodium falciparum parasitaemia in Angolan children exhibiting different severe malaria syndromes., Methods: A case-control study was designed with 430 malaria cases (n = 288 severe malaria and n = 142 uncomplicated malaria) and 319 uninfected controls, attending a central paediatric hospital in Luanda. Severe malaria syndromes were cerebral malaria (n = 130), severe malaria anaemia (n = 30) and hyperparasitaemia (n = 128). Quantitative trait locus analysis was carried out to study HbS association to parasite densities., Results: Previously reported HbS protection against severe malaria was confirmed in case-control analysis (P = 2 × 10(-13)) and corroborated by transmission disequilibrium test (P = 4 × 10(-3)). High parasite density protection conferred by HbS was detectable within severe malaria patients (P = 0.04). Stratifying severe malaria patients according parasite densities, it was found that HbS was highly associated to hyperparasitaemia protection (P = 1.9 × 10(-9)) but did not protect non-hyperparasitaemic children against severe malaria complications, namely cerebral malaria and severe malaria anaemia. Many studies have shown that HbS protects from severe malaria and controls parasite densities but the analysis further suggests that HbS protection against severe malaria syndromes was at a large extent correlated with control of parasitaemia levels., Conclusions: This study supports the hypothesis that HbS confers resistance to hyperparasitaemia in patients exhibiting severe malaria syndromes and highlights that parasitaemia should be taken into account when evaluating HbS protection in severe malaria.
- Published
- 2015
- Full Text
- View/download PDF
11. Coronary microvascular ischemia in hypertrophic cardiomyopathy - a pixel-wise quantitative cardiovascular magnetic resonance perfusion study.
- Author
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Ismail TF, Hsu LY, Greve AM, Gonçalves C, Jabbour A, Gulati A, Hewins B, Mistry N, Wage R, Roughton M, Ferreira PF, Gatehouse P, Firmin D, O'Hanlon R, Pennell DJ, Prasad SK, and Arai AE
- Subjects
- Adult, Aged, Algorithms, Cardiomyopathy, Hypertrophic pathology, Cardiomyopathy, Hypertrophic physiopathology, Contrast Media, Female, Fibrosis, Humans, Hyperemia physiopathology, Image Interpretation, Computer-Assisted, Male, Middle Aged, Myocardial Ischemia pathology, Myocardial Ischemia physiopathology, Myocardium pathology, Organometallic Compounds, Predictive Value of Tests, Severity of Illness Index, Time Factors, Vasodilator Agents, Cardiomyopathy, Hypertrophic diagnosis, Coronary Circulation, Coronary Vessels physiopathology, Magnetic Resonance Imaging, Microcirculation, Microvessels physiopathology, Myocardial Ischemia diagnosis, Myocardial Perfusion Imaging methods
- Abstract
Background: Microvascular dysfunction in HCM has been associated with adverse clinical outcomes. Advances in quantitative cardiovascular magnetic resonance (CMR) perfusion imaging now allow myocardial blood flow to be quantified at the pixel level. We applied these techniques to investigate the spectrum of microvascular dysfunction in hypertrophic cardiomyopathy (HCM) and to explore its relationship with fibrosis and wall thickness., Methods: CMR perfusion imaging was undertaken during adenosine-induced hyperemia and again at rest in 35 patients together with late gadolinium enhancement (LGE) imaging. Myocardial blood flow (MBF) was quantified on a pixel-by-pixel basis from CMR perfusion images using a Fermi-constrained deconvolution algorithm. Regions-of-interest (ROI) in hypoperfused and hyperemic myocardium were identified from the MBF pixel maps. The myocardium was also divided into 16 AHA segments., Results: Resting MBF was significantly higher in the endocardium than in the epicardium (mean ± SD: 1.25 ± 0.35 ml/g/min versus 1.20 ± 0.35 ml/g/min, P<0.001), a pattern that reversed with stress (2.00 ± 0.76 ml/g/min versus 2.36 ± 0.83 ml/g/min, P<0.001). ROI analysis revealed 11 (31%) patients with stress MBF lower than resting values (1.05 ± 0.39 ml/g/min versus 1.22 ± 0.36 ml/g/min, P=0.021). There was a significant negative association between hyperemic MBF and wall thickness (β=-0.047 ml/g/min per mm, 95% CI: -0.057 to -0.038, P<0.001) and a significantly lower probability of fibrosis in a segment with increasing hyperemic MBF (odds ratio per ml/g/min: 0.086, 95% CI: 0.078 to 0.095, P=0.003)., Conclusions: Pixel-wise quantitative CMR perfusion imaging identifies a subgroup of patients with HCM that have localised severe microvascular dysfunction which may give rise to myocardial ischemia.
- Published
- 2014
- Full Text
- View/download PDF
12. inTB - a data integration platform for molecular and clinical epidemiological analysis of tuberculosis.
- Author
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Soares P, Alves RJ, Abecasis AB, Penha-Gonçalves C, Gomes MG, and Pereira-Leal JB
- Subjects
- Biomedical Research, Humans, Internet, Molecular Epidemiology, Molecular Typing, User-Computer Interface, Computational Biology methods, Database Management Systems, Mycobacterium tuberculosis classification, Mycobacterium tuberculosis genetics, Mycobacterium tuberculosis isolation & purification, Tuberculosis
- Abstract
Background: Tuberculosis is currently the second highest cause of death from infectious diseases worldwide. The emergence of multi and extensive drug resistance is threatening to make tuberculosis incurable. There is growing evidence that the genetic diversity of Mycobacterium tuberculosis may have important clinical consequences. Therefore, combining genetic, clinical and socio-demographic data is critical to understand the epidemiology of this infectious disease, and how virulence and other phenotypic traits evolve over time. This requires dedicated bioinformatics platforms, capable of integrating and enabling analyses of this heterogeneous data., Results: We developed inTB, a web-based system for integrated warehousing and analysis of clinical, socio-demographic and molecular data for Mycobacterium sp. isolates. As a database it can organize and display data from any of the standard genotyping methods (SNP, MIRU-VNTR, RFLP and spoligotype), as well as an extensive array of clinical and socio-demographic variables that are used in multiple countries to characterize the disease. Through the inTB interface it is possible to insert and download data, browse the database and search specific parameters. New isolates are automatically classified into strains according to an internal reference, and data uploaded or typed in is checked for internal consistency. As an analysis framework, the system provides simple, point and click analysis tools that allow multiple types of data plotting, as well as simple ways to download data for external analysis. Individual trees for each genotyping method are available, as well as a super tree combining all of them. The integrative nature of inTB grants the user the ability to generate trees for filtered subsets of data crossing molecular and clinical/socio-demografic information. inTB is built on open source software, can be easily installed locally and easily adapted to other diseases. Its design allows for use by research laboratories, hospitals or public health authorities. The full source code as well as ready to use packages is available at http://www.evocell.org/inTB., Conclusions: To the best of our knowledge, this is the only system capable of integrating different types of molecular data with clinical and socio-demographic data, empowering researchers and clinicians with easy to use analysis tools that were not possible before.
- Published
- 2013
- Full Text
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13. Distinct placental malaria pathology caused by different Plasmodium berghei lines that fail to induce cerebral malaria in the C57BL/6 mouse.
- Author
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Rodrigues-Duarte L, de Moraes LV, Barboza R, Marinho CR, Franke-Fayard B, Janse CJ, and Penha-Gonçalves C
- Subjects
- Animals, Disease Models, Animal, Female, Mice, Mice, Inbred C57BL, Parasitemia parasitology, Parasitemia pathology, Plasmodium, Pregnancy, Malaria parasitology, Malaria pathology, Placenta parasitology, Placenta pathology, Plasmodium berghei pathogenicity, Pregnancy Complications, Infectious parasitology, Pregnancy Complications, Infectious pathology
- Abstract
Background: Placental malaria (PM) is one major feature of malaria during pregnancy. A murine model of experimental PM using BALB/c mice infected with Plasmodium berghei ANKA was recently established, but there is need for additional PM models with different parasite/host combinations that allow to interrogate the involvement of specific host genetic factors in the placental inflammatory response to Plasmodium infection., Methods: A mid-term infection protocol was used to test PM induction by three P. berghei parasite lines, derived from the K173, NK65 and ANKA strains of P. berghei that fail to induce experimental cerebral malaria (ECM) in the susceptible C57BL/6 mice. Parasitaemia course, pregnancy outcome and placenta pathology induced by the three parasite lines were compared., Results: The three P. berghei lines were able to evoke severe PM pathology and poor pregnancy outcome features. The results indicate that parasite components required to induce PM are distinct from ECM. Nevertheless, infection with parasites of the ANKAΔpm4 line, which lack expression of plasmepsin 4, displayed milder disease phenotypes associated with a strong innate immune response as compared to infections with NK65 and K173 parasites., Conclusions: Infection of pregnant C57BL/6 females with K173, NK65 and ANKAΔpm4 P. berghei parasites provide experimental systems to identify host molecular components involved in PM pathogenesis mechanisms.
- Published
- 2012
- Full Text
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14. Improvement of genetic stability in lymphocytes from Fanconi anemia patients through the combined effect of α-lipoic acid and N-acetylcysteine.
- Author
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Ponte F, Sousa R, Fernandes AP, Gonçalves C, Barbot J, Carvalho F, and Porto B
- Subjects
- Adult, Antioxidants metabolism, Cells, Cultured, Chromosomal Instability drug effects, Chromosomal Instability genetics, Fanconi Anemia genetics, Female, Humans, Lymphocytes drug effects, Male, Oxidative Stress drug effects, Oxidative Stress genetics, Young Adult, Acetylcysteine pharmacology, Fanconi Anemia metabolism, Lymphocytes metabolism, Thioctic Acid pharmacology
- Abstract
Fanconi Anemia (FA) is a rare genetic disorder, characterized by progressive bone marrow failure and increased predisposition to cancer. Despite being highly heterogeneous, all FA patients are hypersensitive to alkylating agents, in particular to 1,2:3,4-diepoxybutane (DEB), and to oxidative damage. Recent studies point to defective mitochondria in FA cells, which is closely related with increased production of reactive oxygen species (ROS) and concomitant depletion of antioxidant defenses, of which glutathione is a well-known biomarker.The objective of the present work is to evaluate the putative protective effect of α-lipoic acid (α-LA), a mitochondrial protective agent, and N-acetylcysteine (NAC), a direct antioxidant and a known precursor for glutathione synthesis, in spontaneous and DEB-induced chromosome instability (CI) in lymphocyte cultures from FA patients.For that purpose, lymphocyte cultures from 15 FA patients and 24 healthy controls were pre-treated with 20 μM α-LA, 500 μM NAC and α-LA plus NAC at the same concentrations, and some of them were exposed to DEB (0.05 μg/ml). A hundred metaphases per treatment were scored to estimate the relative frequency of spontaneous and DEB-induced chromosome breakage.The obtained results revealed that a cocktail of α-LA and NAC can drastically improve the genetic stability in FA lymphocytes in vitro, decreasing CI by 60% and 80% in cultures from FA patients and FA mosaic/chimera patients, respectively. These results suggest that the studied cocktail can be used as a prophylactic approach to delay progressive clinical symptoms in FA patients caused by CI, which can culminate in the delay of the progressive bone marrow failure and early cancer development.
- Published
- 2012
- Full Text
- View/download PDF
15. Contact Heat Evoked Potentials Using Simultaneous Eeg And Fmri And Their Correlation With Evoked Pain.
- Author
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Roberts K, Papadaki A, Gonçalves C, Tighe M, Atherton D, Shenoy R, McRobbie D, and Anand P
- Abstract
Background: The Contact Heat Evoked Potential Stimulator (CHEPS) utilises rapidly delivered heat pulses with adjustable peak temperatures to stimulate the differential warm/heat thresholds of receptors expressed by Adelta and C fibres. The resulting evoked potentials can be recorded and measured, providing a useful clinical tool for the study of thermal and nociceptive pathways. Concurrent recording of contact heat evoked potentials using electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) has not previously been reported with CHEPS. Developing simultaneous EEG and fMRI with CHEPS is highly desirable, as it provides an opportunity to exploit the high temporal resolution of EEG and the high spatial resolution of fMRI to study the reaction of the human brain to thermal and nociceptive stimuli., Methods: In this study we have recorded evoked potentials stimulated by 51° C contact heat pulses from CHEPS using EEG, under normal conditions (baseline), and during continuous and simultaneous acquisition of fMRI images in ten healthy volunteers, during two sessions. The pain evoked by CHEPS was recorded on a Visual Analogue Scale (VAS)., Results: Analysis of EEG data revealed that the latencies and amplitudes of evoked potentials recorded during continuous fMRI did not differ significantly from baseline recordings. fMRI results were consistent with previous thermal pain studies, and showed Blood Oxygen Level Dependent (BOLD) changes in the insula, post-central gyrus, supplementary motor area (SMA), middle cingulate cortex and pre-central gyrus. There was a significant positive correlation between the evoked potential amplitude (EEG) and the psychophysical perception of pain on the VAS., Conclusion: The results of this study demonstrate the feasibility of recording contact heat evoked potentials with EEG during continuous and simultaneous fMRI. The combined use of the two methods can lead to identification of distinct patterns of brain activity indicative of pain and pro-nociceptive sensitisation in healthy subjects and chronic pain patients. Further studies are required for the technique to progress as a useful tool in clinical trials of novel analgesics.
- Published
- 2008
- Full Text
- View/download PDF
16. Improved isolation of murine hepatocytes for in vitro malaria liver stage studies.
- Author
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Gonçalves LA, Vigário AM, and Penha-Gonçalves C
- Subjects
- Animals, Cell Culture Techniques, Cell Survival, Cells, Cultured, Collagenases metabolism, Dissection, Flow Cytometry instrumentation, Hepatocytes cytology, Mice, Perfusion, Plasmodium, Povidone, Silicon Dioxide, Transfection, Cell Separation methods, Hepatocytes parasitology, Malaria pathology
- Abstract
Background: Primary hepatocyte cultures are a valuable tool for the understanding of cellular and molecular phenomena occurring during malaria liver stage. This paper describes an improved perfusion/dissociation procedure to isolate hepatocytes from mouse liver that is suitable for malaria studies and allows reproducible preparation of primary hepatocytes with consistent cell yields and controlled purity., Results: This protocol is a detailed description of a technique to isolate and culture mouse hepatocytes and represents an improvement over previous descriptions of hepatocyte isolation for malaria studies, regarding three technical aspects: (1) dissociation reagents choice; (2) cell separation gradient and (3) cell purity control. Cell dissociation was optimized for a specific collagenase digestion media. The cell dissociation step was improved by using a three-layer discontinuous gradient. A cell purity check was introduced to monitor the expression of CD95 on hepatocytes using flow cytometry methods., Conclusion: The procedure described allows reproducible recovery of one to three million hepatocytes per preparation with cell purity of about 90% as determined by FACS analysis. Completion of the protocol is usually achieved in about four hours per preparation and pooling is suggested for multiple preparations of larger number of cells.
- Published
- 2007
- Full Text
- View/download PDF
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