Effect of fetal bovine serum on Candida glabrata cultures

Dissertação de mestrado integrado em Engenharia Biomédica (área de especialização em Engenharia Clínica)

Critical analysis and extension of the Hirshfeld atoms in molecules

The computational approach to the Hirshfeld [Theor. Chim. Acta 44, 129 (1977)] atom in a molecule is critically investigated, and several difficulties are highlighted. It is shown that these difficulties are mitigated by an alternative, iterative version, of the Hirshfeld partitioning procedure. The iterative scheme ensures that the Hirshfeld definition represents a mathematically proper information entropy, allows the Hirshfeld approach to be used for charged molecules, eliminates arbitrariness in the choice of the promolecule, and increases the magnitudes of the charges. The resulting "Hirshfeld-I charges" correlate well with electrostatic potential derived atomic charges

Critical analysis and extension of the Hirshfeld atoms in molecules

The computational approach to the Hirshfeld [Theor. Chim. Acta 44, 129 (1977)] atom in a molecule is critically investigated, and several difficulties are highlighted. It is shown that these difficulties are mitigated by an alternative, iterative version, of the Hirshfeld partitioning procedure. The iterative scheme ensures that the Hirshfeld definition represents a mathematically proper information entropy, allows the Hirshfeld approach to be used for charged molecules, eliminates arbitrariness in the choice of the promolecule, and increases the magnitudes of the charges. The resulting "Hirshfeld-I charges" correlate well with electrostatic potential derived atomic charges

Correcting mortality for loss to follow-up: a nomogram applied to antiretroviral treatment programmes in sub-Saharan Africa

Background The World Health Organization estimates that in sub-Saharan Africa about 4 million HIV-infected patients had started antiretroviral therapy (ART) by the end of 2008. Loss of patients to follow-up and care is an important problem for treatment programmes in this region. As mortality is high in these patients compared to patients remaining in care, ART programmes with high rates of loss to follow-up may substantially underestimate mortality of all patients starting ART. Methods and Findings We developed a nomogram to correct mortality estimates for loss to follow-up, based on the fact that mortality of all patients starting ART in a treatment programme is a weighted average of mortality among patients lost to follow-up and patients remaining in care. The nomogram gives a correction factor based on the percentage of patients lost to follow-up at a given point in time, and the estimated ratio of mortality between patients lost and not lost to follow-up. The mortality observed among patients retained in care is then multiplied by the correction factor to obtain an estimate of programme-level mortality that takes all deaths into account. A web calculator directly calculates the corrected, programme-level mortality with 95% confidence intervals (CIs). We applied the method to 11 ART programmes in sub-Saharan Africa. Patients retained in care had a mortality at 1 year of 1.4% to 12.0%; loss to follow-up ranged from 2.8% to 28.7%; and the correction factor from 1.2 to 8.0. The absolute difference between uncorrected and corrected mortality at 1 year ranged from 1.6% to 9.8%, and was above 5% in four programmes. The largest difference in mortality was in a programme with 28.7% of patients lost to follow-up at 1 year. Conclusions The amount of bias in mortality estimates can be large in ART programmes with substantial loss to follow-up. Programmes should routinely report mortality among patients retained in care and the proportion of patients lost. A simple nomogram can then be used to estimate mortality among all patients who started ART, for a range of plausible mortality rates among patients lost to follow-up.

Mean CD4 cell count changes in patients failing a first-line antiretroviral therapy in resource-limited settings

Background Changes in CD4 cell counts are poorly documented in individuals with low or moderate-level viremia while on antiretroviral treatment (ART) in resource-limited settings. We assessed the impact of on-going HIV-RNA replication on CD4 cell count slopes in patients treated with a first-line combination ART. Method Naïve patients on a first-line ART regimen with at least two measures of HIV-RNA available after ART initiation were included in the study. The relationships between mean CD4 cell count change and HIV-RNA at 6 and 12 months after ART initiation (M6 and M12) were assessed by linear mixed models adjusted for gender, age, clinical stage and year of starting ART. Results 3,338 patients were included (14 cohorts, 64% female) and the group had the following characteristics: a median follow-up time of 1.6 years, a median age of 34 years, and a median CD4 cell count at ART initiation of 107 cells/μL. All patients with suppressed HIV-RNA at M12 had a continuous increase in CD4 cell count up to 18 months after treatment initiation. By contrast, any degree of HIV-RNA replication both at M6 and M12 was associated with a flat or a decreasing CD4 cell count slope. Multivariable analysis using HIV-RNA thresholds of 10,000 and 5,000 copies confirmed the significant effect of HIV-RNA on CD4 cell counts both at M6 and M12. Conclusion In routinely monitored patients on an NNRTI-based first-line ART, on-going low-level HIV-RNA replication was associated with a poor immune outcome in patients who had detectable levels of the virus after one year of ART.

Gene transfer of hepatocyte growth factor by electroporation reduces bleomycin-induced lung fibrosis

Abnormal alveolar wound repair contributes to the development of pulmonary fibrosis after lung injury. Hepatocyte growth factor (HGF) is a potent mitogenic factor for alveolar epithelial cells and may therefore improve alveolar epithelial repair in vitro and in vivo. We hypothesized that HGF could increase alveolar epithelial repair in vitro and improve pulmonary fibrosis in vivo. Alveolar wound repair in vitro was determined using an epithelial wound repair model with HGF-transfected A549 alveolar epithelial cells. Electroporation-mediated, nonviral gene transfer of HGF in vivo was performed 7 days after bleomycin-induced lung injury in the rat. Alveolar epithelial repair in vitro was increased after transfection of wounded epithelial monolayers with a plasmid encoding human HGF, pCikhHGF [human HGF (hHGF) gene expressed from the cytomegalovirus (CMV) immediate-early promoter and enhancer] compared with medium control. Electroporation-mediated in vivo HGF gene transfer using pCikhHGF 7 days after intratracheal bleomycin reduced pulmonary fibrosis as assessed by histology and hydroxyproline determination 14 days after bleomycin compared with controls treated with the same vector not containing the HGF sequence (pCik). Lung epithelial cell proliferation was increased and apoptosis reduced in hHGF-treated lungs compared with controls, suggesting increased alveolar epithelial repair in vivo. In addition, profibrotic transforming growth factor-beta1 (TGF-beta1) was decreased in hHGF-treated lungs, indicating an involvement of TGF-beta1 in hHGF-induced reduction of lung fibrosis. In conclusion, electroporation-mediated gene transfer of hHGF decreases bleomycin-induced pulmonary fibrosis, possibly by increasing alveolar epithelial cell proliferation and reducing apoptosis, resulting in improved alveolar wound repair.

Frequent fusion of the JAZF1 and JJAZ1 genes in endometrial stromal tumors

Endometrial stromal tumors are divided into three types: benign stromal nodules, endometrial stromal sarcomas, and undifferentiated endometrial sarcomas. A variety of cytogenetic abnormalities involving chromosome 7 have been reported in endometrial stromal sarcomas, including a recurrent t(7;17)(p15;q21). We have identified two zinc finger genes, which we have termed JAZF1 and JJAZ1, at the sites of the 7p15 and 17q21 breakpoints. Analyses of tumor RNA indicate that a JAZF1/JJAZ1 fusion is present in all types of endometrial stromal tumors; however, the fusion appears to be rarer among endometrial stromal sarcomas that would be considered high-grade according to certain classification schemes. These findings suggest that the less malignant endometrial stromal tumors may evolve toward more malignant types, but that some endometrial stromal sarcomas with relatively abundant mitotic activity may compose a biologically distinct group.

Molecular and Biochemical Characterization of Cytosolic Phosphoglucomutase in Maize1 : Expression during Development and in Response to Oxygen Deprivation

Phosphoglucomutase (PGM) catalyzes the interconversion of glucose (Glc)-1- and Glc-6-phosphate in the synthesis and consumption of sucrose. We isolated two maize (Zea mays L.) cDNAs that encode PGM with 98.5% identity in their deduced amino acid sequence. Southern-blot analysis with genomic DNA from lines with different Pgm1 and Pgm2 genotypes suggested that the cDNAs encode the two known cytosolic PGM isozymes, PGM1 and PGM2. The cytosolic PGMs of maize are distinct from a plastidic PGM of spinach (Spinacia oleracea). The deduced amino acid sequences of the cytosolic PGMs contain the conserved phosphate-transfer catalytic center and the metal-ion-binding site of known prokaryotic and eukaryotic PGMs. PGM mRNA was detectable by RNA-blot analysis in all tissues and organs examined except silk. A reduction in PGM mRNA accumulation was detected in roots deprived of O2 for 24 h, along with reduced synthesis of a PGM identified as a 67-kD phosphoprotein on two-dimensional gels. Therefore, PGM is not one of the so-called “anaerobic polypeptides.” Nevertheless, the specific activity of PGM was not significantly affected in roots deprived of O2 for 24 h. We propose that PGM is a stable protein and that existing levels are sufficient to maintain the flux of Glc-1-phosphate into glycolysis under O2 deprivation.

Molecular Characterization of Three Canine Models of Human Rare Bone Diseases: Caffey, van den Ende-Gupta, and Raine Syndromes.

One to two percent of all children are born with a developmental disorder requiring pediatric hospital admissions. For many such syndromes, the molecular pathogenesis remains poorly characterized. Parallel developmental disorders in other species could provide complementary models for human rare diseases by uncovering new candidate genes, improving the understanding of the molecular mechanisms and opening possibilities for therapeutic trials. We performed various experiments, e.g. combined genome-wide association and next generation sequencing, to investigate the clinico-pathological features and genetic causes of three developmental syndromes in dogs, including craniomandibular osteopathy (CMO), a previously undescribed skeletal syndrome, and dental hypomineralization, for which we identified pathogenic variants in the canine SLC37A2 (truncating splicing enhancer variant), SCARF2 (truncating 2-bp deletion) and FAM20C (missense variant) genes, respectively. CMO is a clinical equivalent to an infantile cortical hyperostosis (Caffey disease), for which SLC37A2 is a new candidate gene. SLC37A2 is a poorly characterized member of a glucose-phosphate transporter family without previous disease associations. It is expressed in many tissues, including cells of the macrophage lineage, e.g. osteoclasts, and suggests a disease mechanism, in which an impaired glucose homeostasis in osteoclasts compromises their function in the developing bone, leading to hyperostosis. Mutations in SCARF2 and FAM20C have been associated with the human van den Ende-Gupta and Raine syndromes that include numerous features similar to the affected dogs. Given the growing interest in the molecular characterization and treatment of human rare diseases, our study presents three novel physiologically relevant models for further research and therapy approaches, while providing the molecular identity for the canine conditions.

Zelfsturend leren wordt je aangeleerd: Het effectief professionaliseren van leraren in het bevorderen van zelfsturend leren in het basisonderwijs

Zelfsturend leren is cruciaal voor het leren van leerlingen. Verschillende studies geven echter aan dat zelfsturend leren in het basisonderwijs nauwelijks op gang komt. In dit onderzoek werken onderwijsprofessionals en onderzoekers samen aan het optimaliseren van een professionaliseringsaanpak waarin 55 basisschoolleraren worden getraind en begeleid in het bevorderen van zelfsturend leren van hun leerlingen. Een belangrijk kenmerk van deze aanpak is dat leraren niet worden getraind volgens een formeel professionaliseringstraject, maar dat de professionele ontwikkeling van leraren is ingebed in de eigen lespraktijk en dat leraren van en met elkaar leren. De effectiviteit van de ontwikkelde aanpak wordt onderzocht op de mate van zelfsturend leren, motivatie, metacognitie en leerprestaties van leerlingen en de professionele ontwikkeling van deelnemende leraren.

Diagramas de Ellingham e de Van't Hoff: algumas considerações

The main subject of this article is to show the parallelism betwen the Ellingham and Van't Hoff diagrams. The first one is a graphic representation of the changes in the standard Gibbs free energy (deltarGtheta) as a function of T and was introduced by Ellingham in 1944, in order to study metallurgic processes involving oxides and sulphides. On the other hand, the Van't Hoff diagram is a representation of the function ln K versus (1/T). The equivalence between both diagrams is easily demonstrated, making simple mathematical manipulations. In order to show the parallelism between both diagrams, they are presented briefly and two examples are discussed. The comparison of the both diagrams surely will be helpful to students and teachers in their learning and teaching activities, and will certainly enrich important aspects of chemical thermodynamics.