PubMed Health⌕ Search

Biomedical subjects

F Araújo

Publications and source records attributed to F Araújo.

At least 19 recordsLinked to original sources
PubMed2006

Weak D type 2 is the most prevalent weak D type in Portugal.

The weak D phenotype is the most common D variant, with a frequency of 0.2-1% in Caucasian individuals. There are several weak D types, with different frequencies in European countries, which may pose serologic problems and have the potential for alloimmunization. Samples from Portuguese individuals were tested for RhD by two or three distinct monoclonal and oligoclonal antisera, in direct agglutination tests. When discrepant results were observed, samples were tested with panels of monoclonal anti-D by LISS-indirect antiglobulin test. Cases that reacted weakly with IgM but positive with IgG anti-D were analysed by PCR-sequence-specific primers and real-time PCR. Ninety-nine samples were referred after being characterized as weak D. This genotype was recognized, with a preponderance of weak D type 2 (63.6%) over type 1 (16.2%) and 3 (14.1%). The high incidence of weak D type 2 in our population is in marked contrast to studies performed in other European populations and might be due to our sample selection criteria or ethnic variation. There are advantages in genotyping serologically depressed D samples to avoid the waste of D-negative RBC units and the use of immunoglobulin in pregnant women, who have no risk of alloimmunization.

Genotype↗
PubMed2005

Genetic polymorphisms and risk of recurrent deep venous thrombosis in young people: prospective cohort study.

OBJECTIVE: To determine the incidence of deep venous thrombosis (DVT) recurrence in young people, and its association with some genetic polymorphisms (FV G1691A, FII G20210A, MTHFR C677T, PAI-1 4G/5G). DESIGN: Prospective cohort study. METHODS: A database was established prospectively to follow-up a cohort of unselected patients who had had a first episode of objectively proven DVT under the age of 40 years. All patients had DNA analysis for heritable thrombophilia. We excluded patients with deficiency of antithrombin, protein C or protein S, malignant disease, antiphospholipid syndrome, or a requirement for long-term antithrombotic treatment. The end-point was objective evidence of symptomatic DVT recurrence. RESULTS: Eighty-seven patients were enrolled in the study. Mean duration of follow-up was 4.07 years. At 2 years, the cumulative recurrence rate was 19.3%. The risk of risk was not related to presence or absence of laboratory evidence of genetic polymorphisms: FV G1619A (HR 1.26 [95%CI: 0.64-2.46]; p = 0.51), FII G20210A (HR 0.81 [95%CI: 0.35-1.89]; p = 0.62), MTHFR C677T (HR 1.26 [95%CI: 0.56-2.81]; p = 0.58), PAI-1 4G/5G (0.84 [95%CI: 0.35-2.05]; p = 0.71). CONCLUSION: In this study, the risk of recurrent deep venous thrombosis in young people was not related with the presence of FV G1691A, FII G20210A, MTHFR C677T or PAI-1 4G/5G polymorphisms.

5,10-Methylenetetrahydrofolate Reductase (FADH2)↗
PubMed2005

Prevalences of hyperhomocysteinemia, unfavorable cholesterol profile and hypertension in European populations.

BACKGROUND: Hyperhomocysteinemia (HHCY) is a risk factor for cardiovascular diseases (CVD). HHCY may interact with hypertension (HTEN) and an unfavorable cholesterol profile (UNFAVCHOL) to alter the risk of CVD. OBJECTIVES: To estimate the prevalences of HHCY (1) isolated and (2) in combination with UNFAVCHOL and/or HTEN in different age categories. To provide information that may improve the screening and treatment of subjects at risk of CVD. DESIGN: Cross-sectional data on 12,541 men and 12,948 women aged 20 + y were used from nine European studies. RESULTS: The prevalence of isolated HHCY was 8.5% in subjects aged 20-40 y, 4.7% in subjects aged 40-60 y and 5.9% in subjects aged over 60 y. When combining all age groups, 5.3% had isolated HHCY and an additional 5.6% had HHCY in combination with HTEN and/or UNFAVCHOL. The combinations of risk factors increased with age and, except for HHCY&UNFAVCHOL, were more prevalent than predicted by chance. Of the young subjects (20-40 y), 24% suffered from one or more of the investigated CVD risk factors. This figure was 75.1% in the old subjects (60+ years). CONCLUSIONS: A substantial number of subjects in selected European populations have HHCY (10.9%). In half of these cases, subjects suffer also from other CVD risk factors like UNFAVCHOL and HTEN. Older people in particular tend to have more than one risk factor. Healthcare professionals should be aware of this when screening and treating older people not only for the conventional CVD risk factors like UNFAVCHOL and HTEN but also HHCY, as this can easily be reduced through increased intake of folic acid via supplement or foods fortified with folic acid.

Adult↗
PubMed2002

The PORtromb Project: prothrombin G20210A mutation and venous thromboembolism in young people.

Recently a new identified genetic variant in the 3'-untranslated region of the prothrombin gene (G20210A allele) associated with increased plasma prothrombin levels has been linked to an increased risk of venous thromboembolism (VTE). To determine the importance of this G20210A allele as a causative risk factor for VTE in the general population, we analysed the data of an epidemiologic investigation on thrombophilia in young people, the Oporto Thrombophilia Study (PORtromb). Forty cases (mean age: 27 yr old) with a first episode of VTE under 40 yr old, and 100 healthy subjects, were evaluated. Heterozygosity for the G20210A allele was present in 12.5% of VTE cases and in 5% of controls, indicating a possible marginal increase of VTE risk in carriers of the allele (odds ratio: 2.71: 95% CI 0.74-9.95).

3' Untranslated Regions↗
PubMed2002

Capillary leakage syndrome: a case report and a review.

Capillary leakage Syndrome (CLS) is a rare clinical syndrome, that was first described in 1960, characterized by acute episodes of generalized edema, hemoconcentration, hypoproteinemia and monoclonal gammopathy, in the vast majority of cases. We describe a 39-year-old man with anasarca, bilateral pleural and pericardial effusions, ascites and diffuse alveolo-intersticial edema. Clinical and laboratory findings were consistent with an acute episode of CLS. Treatment with prednisone, furosemide and aminophylline was started, which lead to a gradual improvement in 48 hours. Pathophysiologically there is an increase in capillary permeability with the extravasation of fluid and plasmatic proteins to the extravascular space that can lead to hypovolaemic shock. In the second phase there is a reentry of the fluid overload leading to pulmonary edema. The etiology of this hyperpermeability still remains unclear. The role of cytokines has become central in the comprehension of pathophysiology of CLS. Adhesion molecules are probably also involved in the genesis of capillary leakage. CLS treatment remains empirical. However, at present it seems that the association of steroids with furosemide, aminophylline and terbutaline are capable of controlling the clinical manifestation of the acute episodes in most cases. To our knowledge no prophylatic therapy has clearly proven its efficacy. There are only a few series analyzing the long-term evolution of patients with CLS. Further studies are necessary with the objective to collect enough patients with CLS to observe natural history of the disease and evaluate the efficacy of empiric treatments.

Adult↗
PubMed2002

Blood group antigen profile predicted by molecular biology-use of real-time polymerase chain reaction to genotype important KEL, JK,RHD, and RHCE alleles.

The most clinically important blood group systems in transfusion medicine, excluding the ABO system, are the RH, Kell, and Kidd systems. Alloantibodies to antigens of these systems may be produced following blood transfusion or during pregnancy and can result in serious hemolytic transfusion reactions and hemolytic disease of the newborn. We developed rapid and robust techniques for RHD, RHCE, KEL, and JK genotyping with the use of a real-time polymerase chain reaction instrument. Two fluorescence-based methods for the detection of amplification products were used: for KEL1/KEL2, JK1/JK2, and RHE/RHe (exon 5) we used the hybridization probes protocol; for RHC/RHc the analysis was done in sequences of exon 1 for RHC and exon 2 for RHc; and for RHD, analysis was done in sequences of intron 4, exon 7, and exon 4 pseudogene using the SYBR Green I protocol. The genotyping tests were validated with samples from 85 Caucasian Portuguese and 15 Black European blood donors. Complete phenotype-genotype correlations were obtained. The potential use of the presented methods can be predicted in clinical transfusion medicine, allowing appropriate monitoring, early intervention, and improved care. When blood group genotyping techniques are necessary, this methodology is highly competitive for a routine laboratory.

Journal Article↗
PubMed2001

Influence of the interval between the administration of doxorubicin and paclitaxel on the pharmacokinetics of these drugs in patients with locally advanced breast cancer.

PURPOSE: The combination of bolus doxorubicin followed by a 3-h infusion of paclitaxel has high antitumor activity in patients with metastatic breast cancer, but is limited by unexpected cardiac toxicity. In contrast, the administration of the two drugs 16 h apart has similar antitumor activity but less cardiac toxicity. The purpose of this study was to compare the pharmacokinetics of these drugs when doxorubicin administration preceded paclitaxel by 30 min or by 24 h. PATIENTS AND METHODS: Women with locally advanced breast cancer were treated with doxorubicin (60 mg/m2 i.v. bolus) followed 24 h later by paclitaxel (200 mg/m2 i.v. over 3 h) for six cycles (four before and two after surgery). In one of the first two cycles doxorubicin preceded paclitaxel by 30 min instead of 24 h, with plasma sampling for pharmacokinetic analysis up to 48 h. Determination of drug levels in plasma was done by HPLC. RESULTS: A total of 28 patients were included. No clinical cardiac toxicity was observed but five patients discontinued doxorubicin-paclitaxel treatment after four cycles because of a decrease in LVEF of at least 15% from baseline or to less than 50%. While paclitaxel pharmacokinetics were not changed, there was a 30% and an 80% increase in the AUC0, 24h for doxorubicin and doxorubicinol, respectively, when the drugs were administered 30 min instead of 24 h apart. Even when paclitaxel was given 24 h after doxorubicin, there was a rebound 240% increase in the plasma concentration of doxorubicinol. CONCLUSIONS: Paclitaxel interferes with the pharmacokinetics of doxorubicin leading to higher systemic exposure to both doxorubicin and doxorubicinol, which is more evident when the plasma concentration of the anthracyclines is higher. This interference may explain the higher incidence of cardiac toxicity observed when the two drugs are administered within a short interval.

Adult↗
PubMed2001

Rapid genotyping of the major alleles at the Duffy (FY) blood group locus using real-time fluorescence polymerase chain reaction.

The Duffy blood group system has clinical importance due to involvement in transfusion reactions and hemolytic disease of the newborn. Recently, the molecular basis of the two alleles, FY*A and FY*B (125G>A), and the mutation situated in the promoter region of the FY gene (-33T>C), have been elucidated. In order to develop an accurate, easy, and rapid genotyping method, we describe a procedure using the LightCycler. Samples from 53 Caucasian Portuguese blood donors and 7 black, healthy, European individuals were phenotyped with commercial antisera. DNA was extracted from blood samples and the relevant sequences were amplified with the same cycling conditions, using real-time polymerase chain reaction. The melting point of the FY*A allele was 63 degrees C and of the FY*B allele, 55 degrees C. The allele without mutation at the promoter region had a melting point at 64 degrees C and the FY*B silent allele at 58 degrees C. The results in Caucasian individuals were similar to those found in European and American populations. When FY genotyping techniques are necessary, the methodology described is preferable to conventional methods as it is reliable, high speed, and uses small volumes, providing a highly competitive technology for use by a routine laboratory.

Journal Article↗
PubMed2000

Hydrops fetalis associated with erythrocyte pyruvate kinase deficiency.

UNLABELLED: The authors report a case of hydrops fetalis due to severe pyruvate kinase deficiency, the most unusual clinical manifestation of this disease. CONCLUSION: Pyruvate kinase deficiency, as other erythrocyte enzymopathies, must be considered in the differential diagnosis of non-immune hydrops fetalis. This has important implications for clinical investigations, therapy and genetic counselling.

Anemia, Hemolytic, Congenital Nonspherocytic↗
PubMed2000

Paralytic shellfish toxins in the freshwater cyanobacterium Aphanizomenon flos-aquae, isolated from Montargil reservoir, Portugal.

Montargil reservoir, located in a dry flat area in the centre of Portugal, was filled in 1958 to fulfil agricultural, electric and industrial requirements. In May 1996, an intensive bloom of phytoplankton was detected. The algal community was strongly dominated by cyanobacteria with predominance of Aphanizomenon flos-aquae from May to June and Microcystis aeruginosa from July to August. Extracts of samples collected during the bloom period showed high toxicity by mouse bioassay. During the M. aeruginosa predominance period, the toxicity was ascribed to the presence of hepatotoxins, but clear symptoms of paralytic shellfish poison were observed when A. flos-aquae was the dominant species. In order to confirm the production of neurotoxins a strain of A. flos-aquae was isolated and established in culture. In this manuscript, we show the morphological characteristics and confirm paralytic shellfish toxins production by the strain isolated and maintained in culture. Identification of the saxitoxin analogs was achieved using high performance liquid chromatography with postcolumn fluorescence derivatization (HPLC-FLD) and liquid chromatographic mass spectrometry technique (LC-MS). The toxins found in the culture extract were GTX5 (64.5 mol%), neoSTX (23.0 mol%), dcSTX (6.1 mol%), STX (5.4 mol%) and GTX6 (1.1 mol%). This is, to our knowledge, the first report of unambiguous evidence of paralytic shellfish toxins produced by freshwater cyanobacteria in Portugal. The toxin profile is rather different from the previously reported PSP producing A. flos-aquae and demonstrates its diversity in terms of toxin production.

Animals↗