Browsing by Author "Mendes, M."
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- Effects of Carica papaya leaf extracts in transcriptional regulation of fetal hemoglobinPublication . Mendes, M.; Canteiro, Beatriz; Delgadinho, Mariana; Oliveira, Ketlyn; Ginete, Catarina; Gomes, Mário; Ribeiro, Edna; Brito, Miguel; Gomes, Anita Q.Purpose: Sickle cell disease (SCD) is one of the most common human genetic disorders, which is caused by a single point mutation (Glu6Val) on the HBB gene. Currently, one of the treatments for this global health problem involves the induction of fetal hemoglobin (HbF). There are some drugs on the market that pharmacologically induce HbF, namely Hydroxyurea (HU), however, their safety concerns and the expensive cost in low- and middle-income countries limit their use. In this context, it is essential to study novel fetal hemoglobin-inducing compounds that have fewer adverse effects and are widely available, such as natural compounds. Therefore, the main aim of this work was to evaluate the effects of Carica Papaya methanolic leaf extracts (CPMLE) in HbF reactivation.
- Effects of quercetin in transcriptional regulation of fetal hemoglobinPublication . Canteiro, B.; Mendes, M.; Delgadinho, Mariana; Oliveira, K.; Ginete, Catarina; Gomes, M.; Brito, Miguel; Gomes, Anita Q.; Ribeiro, EdnaPurpose: Sickle cell disease (SCD) is a genetic blood disorder that affects the shape and transport of red blood cells (RBCs) in blood vessels, leading to various clinical complications. The pharmacological reactivation of Fetal Hemoglobin (HbF) is considered to be a viable therapeutic method in SCD. In this regard, hydroxyurea (HU), a powerful ribonucleotide reductase inhibitor, is being employed as a HbF-inducing pharmaceutical. However, its cytotoxicity, carcinogenic potential, and variable effects limit its use. Thus, a major challenge today is to identify new agents, with high HbF-inducing activity, low cytotoxicity, and available in low- and middle-income countries, such as natural compounds. Quercetin, a natural flavonoid, has been identified as a potential HbF inducer. The main aim of this work was to evaluate Quercetin's role in the reactivation of fetal hemoglobin (HbF) by analyzing the expression of globin and HbF regulatory/silencing genes.
- Evaluation of cell toxicity and DNA and protein binding of green synthesized silver nanoparticlesPublication . Da Costa Ribeiro, Ana Paula; Anbu, S; Alegria, Elisabete; Fernandes, Alexandra; Baptista, Pedro; Mendes, Rita; Matias, A. S.; Mendes, M.; Guedes Da Silva, M. Fátima C.; Pombeiro, ArmandoSilver nanoparticles (AgNPs) were prepared by GREEN chemistry relying on the reduction of AgNO3 by phytochemicals present in black tea extract. AgNPs were fully characterized by transmission electron microscopy (TEM), ultraviolet-visible spectroscopy ((UV-vis)), X-ray diffraction (XRD) and energy dispersive absorption spectroscopy (EDS). The synthesized AgNPs induced a decrease of the cell viability in a dose-dependent manner with a low IC50 (0.5 +/- 0.1 mu M) for an ovarian carcinoma cell line (A2780) compared to primary human fibroblasts (IC50 5.0 +/- 0.1 mu M). The DNA binding capability of CT (calf thymus) DNA was investigated using electronic absorption and fluorescence spectroscopies, circular dichroism and viscosity titration methods. Additionally, the AgNPs strongly quench the intrinsic fluorescence of BSA, as determined by synchronous fluorescence spectra.
- Genetic variability and disease severity in a cohort of Angolan sickle cell disease patientsPublication . Brito, Miguel; Ferreira, J.; Capriello, I.; Ginete, Catarina; Delgadinho, Mariana; Sebastião, Cruz; Mendes, M.; Quinto, F.; Mavunza, F.; Vasconcelos, J.; Cogle, A.Purpose: Sickle Cell Anaemia (SCA) is an inherited autosomal and lethal blood disorder caused by a mutation in the HBB gene that promotes haemoglobin (Hb) polymerization and consequent sickling of red blood cells (RBCs) in hypoxia. Regardless of being a monogenic disease, SCA has a remarkably high clinical heterogeneity in its phenotypic expression. Several factors have been shown to modulate the clinical manifestations of SCA, namely genetic markers such as α-thalassaemia and β-globin cluster haplotypes, that can modulate biological parameters like the degree of haemolytic anaemia or the levels of foetal haemoglobin (HbF).
- Preliminary findings from the follow-up of pregnant sickle cell disease patients in Luanda, AngolaPublication . Brito, Miguel; Ginete, Catarina; Ferreira, J.; Delgadinho, Mariana; Sebastião, Cruz; Mateus, A.; Mendes, M.; Quinto, F.; Simão, F.; Fernandes, F.; Vasconcelos, J.Background: In Angola, the prevalence of Sickle Cell Disease (SCD) is almost 2%, and the carriers reach 21% of the population. Although its presentation tends to be very heterogeneous, chronic hemolytic anemia, frequent painful crises, and extensive organ damage are common features of these patients. Pregnancy in SCD patients is associated with an increase in severe outcomes, namely, a high risk of eclampsia and pre-eclampsia, stroke, and even death. Therefore, it is crucial to maintain continuous medical surveillance during pregnancy, especially in women with previous strokes. Moreover, health services in low- and middle-income countries are generally not prepared to follow these patients. Aims: We aim to present the preliminary findings from the cohort study conducted at the Lucrecia Paim Maternity Hospital (Luanda, Angola), which aims to determine pregnancy complications in SCD women, especially those responsible for maternal death, and, by supporting the obstetric consultations in this hospital, contribute to the reduction of mortality and morbidity rates. Methods: Pregnancy monitoring includes analysis of clinical history and incidents (number of hospitalizations, blood transfusions, strokes, and other clinical complications), hematological and biochemical analysis, transcranial Doppler to assess cerebral hemodynamics and genetic analysis (confirmation of the diagnosis, genotyping of four SNPs in the β-cluster to assess the haplotype, and evaluation of the presence of the 3.7kb deletion of the α-globin gene). Results: To date, 61 women are being followed in the obstetric consultations, with ages from 18 to 40 years old (mean 26.1±5.4). There are no records of previous strokes, although 83.9% of the patients have been previously transfused (47 out of 56), 98.2% have been hospitalized (55 out of 56) due to SCD complications and 19.6% (10 out of 54) had at least one miscarriage. At the first appointment, total hemoglobin values ranged from 4.70 to 10.40 g/dL (n=52, mean 7.18±1.30), erythrocytes from 1.46 to 5.42 x1012/L (n=52, mean 2.46±0,72), white blood cells count from 1.67 to 61.88 x109/L (n=51, mean 12.20±8.69), platelets from 24.2 to 710.0 x109/L (n=52, mean 272.2±155.9), and lactate dehydrogenase (LDH) from 263.3 to 2836.7 (n=50, mean 708.1±450.46). The CAR/CAR haplotype, which is usually associated with a more severe prognosis, is the most prevalent in this population (57.7%, 30 out of 52), followed by the CAR/SEN haplotype (25.0%, 13 out of 52). In this population, 17.3% (9 out of 52) are homozygous for the 3.7kb α-thalassemia deletion and 44.2% (23 out of 52) are carriers. This deletion influences hematological and clinical aspects of sickle cell disease patients, resulting in less severe phenotypes. TCD time-averaged mean of the maximum velocity (TAMMx) at the middle cerebral arteries ranged between 41 to 132 cm/s (n=61, mean 84cm/s), and peak systolic velocity (PSV) from 61 to 180 cm/s (mean 129 cm/s). At the basilar artery level, TAMMx obtained were between 29 to 102 cm/s (n=60, mean 52 cm/s) and PSV ranged from 43 to 141 cm/s (mean 78 cm/s). Summary - Conclusion: The main goal of this project is to study pregnancy-related complications and outcomes by giving support to an Angolan cohort of SCD pregnant women. We also intend to obtain TCD reference values of cerebral blood flow velocities in pregnant women with SCD as a risk predictor of vascular events as there are no values in the literature for this specific population.