1 Hospital Israelita Albert Einstein/Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil
2 Hospital das Clínicas da Universidade Federal do Paraná, Curitiba, Brazil
3 ...Faculdade de Medicina da Universidade de São Paulo, São Paulo, Brazil
4 Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo, Ribeirão Preto, Brazil
5 Faculdade de Ciências Médicas da Universidade Estadual de Campinas, Campinas, Brazil
6 Hospital de Clínicas José de San Martín, Buenos Aires, Argentina
7 Instituto de Hemoterapia de Goiânia, Goiânia, Brazil
8 Hemocentro Regional de Juiz de Fora, Juiz de Fora, Brazil
9 Fundação de Hematologia e Hemoterapia do Amazonas (HEMOAM), Manaus (AM), Brazil
10 Fundação Hemope, Recife, Brazil
11 Hemocentro Regional de Uberaba, Uberaba, Brazil
12 Hospital San José Tec de Monterrey, Monterrey, México, Centro de Hematologia de São Paulo
Correspondence: Nelson Hamerschlak, Centro de Pesquisa Clínica, Instituto Israelita de Ensino e Pesquisa Albert Einstein, Av. Albert Einstein, 627/701, Piso Chinuch, São Paulo (SP), Brazil, CEP 05651-901. E-mail: hamer{at}einstein.br
Background: Associations between aplastic anemia and numerous drugs, pesticides and chemicals have been reported. However, at least 50% of the etiology of aplastic anemia remains unexplained.
Design and Methods: This was a case-control, multicenter, multinational study, designed to identify risk factors for agranulocytosis and aplastic anemia. The cases were patients with diagnosis of aplastic anemia confirmed through biopsy or bone marrow aspiration, selected through an active search of clinical laboratories, hematology clinics and medical records. The controls did not have either aplastic anemia or chronic diseases. A total of 224 patients with aplastic anemia were included in the study, each case was paired with four controls, according to sex, age group, and hospital where the case was first seen. Information was collected on demographic data, medical history, laboratory tests, medications, and other potential risk factors prior to diagnosis.
Results: The incidence of aplastic anemia was 1.6 cases per million per year. Higher rates of benzene exposure ( 30 exposures per year) were associated with a greater risk of aplastic anemia (odds ratio, OR: 4.2; 95% confidence interval, CI: 1.82–9.82). Individuals exposed to chloramphenicol in the previous year had an adjusted OR for aplastic anemia of 8.7 (CI: 0.87–87.93) and those exposed to azithromycin had an adjusted OR of 11.02 (CI 1.14–108.02).
Conclusions: The incidence of aplastic anemia in Latin America countries is low. Although the research study centers had a high coverage of health services, the underreporting of cases of aplastic anemia in selected regions can be discussed. Frequent exposure to benzene-based products increases the risk for aplastic anemia. Few associations with specific drugs were found, and it is likely that some of these were due to chance alone.
Key words: aplastic anemia, incidence, risk factors, benzene.
Patients carrying the FV Leiden or the FII A20210 mutation have a high risk of venous thromboembolism. Among 542 patients with a documented diagnosis of deep venous thrombosis in one leg ...consecutively referred for a thrombophilic work-up, we have retrospectively assessed the rate of objectively documented previous recurrence in carriers of both FV Leiden and FII A20210 mutations. Eighty-two patients had experienced 115 episodes of recurrent venous thromboembolism. The rate of recurrent venous thromboembolism was 29.2% among subjects with and 14.5% in those without deficiencies of natural anticoagulant proteins (p = 0.055), and 24.6% among patients with and 14.0% in those without antiphospholipid antibodies (p = 0.036). The frequency of having a recurrent thromboembolism was 16.2%, 20.0%, and 36.4% among carriers of FV Leiden, FII A20210 mutation, or both gene defects, respectively, and 12.8% in subjects carrying neither mutation (p for trend = 0.004). When adjusted for age, sex, and thrombophilic risk factors, the rate was higher among patients with than in those without deficiencies of natural anticoagulant proteins (OR: 3.0; 95% CI: 1.2-7.5), aPL 2.5 (95% CI: 1.3-4.9), or both FV Leiden and FII A20210 gene mutations (OR 4.8; 95% CI: 1.9-12.2). The rate of previous recurrent venous thromboembolism was significantly higher in subjects carrying both FV Leiden and FII 20210 mutations and was comparable to that observed in subjects with deficiencies of natural anticoagulant proteins or antiphospholipid antibodies.
The aim of this study was to analyze the association between vascular endothelial growth factor (VEGF) expression on tumor cells and other clinicopathologic parameters in breast cancer that could ...give additional information on its prognostic significance. Immunohistochemical analysis of expression of VEGF, estrogen (ER) and progesterone receptor (PR), HER-2/neu, and Ki67 was performed in 233 breast cancers. VEGF expression estimated semiquantitatively was correlated with all the above-mentioned parameters as well as with clinicopathologic characteristics of breast cancer such as menopausal status of patients, tumor size, histologic and nuclear grade, vascular invasion, and lymph node status. Most of the tumor cells and some stromal components expressed VEGF. A higher percentage of VEGF-positive tumor cells was present in premenopausal patients and in ER-negative tumors. In postmenopausal patients tumors with a higher expression of VEGF were associated not only with ER-negative but also with HER-2/neu-positive tumor cells. These ER-negative tumors were characterized by a higher proliferative activity. Angiogenic switch as well as proliferative activity of breast cancer cells probably are unfavorably dependent on estrogen activity. This negative correlation between VEGF expression and ER status may not only shed more light on tumor biology but may also have future therapeutic implications.
Background: Methylenetetrahydrofolate reductase (MTHFR) deficiency leads to impairment in folate metabolism and is implicated as a risk factor for neural tube defects (NTDs). Both C677T and A1298C ...MTHFR mutations are associated with NTDs, in some populations.
Methods: The frequencies of the C677T and A1298C MTHFR mutations were determined in 25 children with NTDs, case mothers and 75 healthy individuals from Sao Paulo City. Both C677T and A1298C mutations were analyzed by PCR-FLRP. The effects of MTHFR mutations on folate, vitamin B12 and homocysteine concentrations were also evaluated.
Results: C677T and A1298C allele frequencies in NTDs children and mothers were similar to that found in controls. Eleven in 23 NTDs patients and 10 in 21 NTDs mothers had folate or vitamin B12 concentrations in the lower end of the normal range. In NTDs children, C677T MTHFR genotypes did not affect vitamins and homocysteine concentrations, but plasma homocysteine was higher (
p=0.028) in patients with 1298AA MTHFR genotype. Moreover, 677CT/1298AA haplotype was associated with lower vitamin B12 concentrations (
p<0.05) in NTDs children.
Conclusions: MTHFR gene mutations may affect vitamin B12 and homocysteine metabolism in Brazilian children with NTDs.
Glanzmann's thrombasthenia (GT) is a genetically heterogeneous autosomal recessive syndrome associated with a bleeding tendency. To elucidate molecular basis of GT we have screened for mutations 30 ...GT patients. On the whole, 21 different candidate causal mutations, 17 in the alphaIIb and 4 in the beta3 gene have been found. Only two (alphaIIb Pro145Ala and IVS3(-3)-418del) have been previously reported. Nine mutations (42.9%) were likely to produce truncated proteins, whereas the remaining 12 were missense mutations that affected highly conserved residues in alphaIIb and beta3 genes. Six mutations were found in different patients suggesting a possible founder effect. The wide spectrum of expressivity, ranging from mild to severe also among patients carrying the same mutations, provided evidence for a role of different loci or circumstantial factors. In conclusion, we have identified a spectrum of unreported mutations that may be of value to unravel the role of specific regions of alphaIIb and beta3 genes.
Objective: This study’s objective was to evaluate the association between venous thromboembolism during pregnancy and the postpartum period and the factor V Arg 506 Gln (factor V Leiden), the ...prothrombin G20210A, and methylenetetrahydrofolate reductase C677T polymorphisms.
Study Design: In this case-control study 42 case patients and 213 control subjects (parous age-matched women without history of thrombosis) were genotyped for all the polymorphisms. Moreover, antiphospholipid antibodies and protein C, protein S, and antithrombin III deficiencies were investigated in each case.
Results: Ten case patients (23.8%) and 4 control subjects (1.9%; odds ratio 16.3, 95% confidence interval 4.8-54.9) carried the factor V Leiden mutation; 13 case patients (31.0%) and 9 control subjects (4.2%; odds ratio 10.2, 95% confidence interval 4.0-25.9) were carriers of the prothrombin G20210A allele. Finally, 12 case patients (28.6%) and 34 control subjects (16.0%; odds ratio 2.1, 95% confidence interval 1.0-4.5) were homozygotes for methylenetetrahydrofolate reductase C677T. Overall, mutations were found in 25 case patients (59.5%) and 47 control patients (22.2%; odds ratio 5.2, 95% confidence interval 4.9-19.6). One patient carried the antithrombin III deficiency and 1 the protein S deficiency, whereas 2 women had a primary antiphospholipid syndrome.
Conclusions: The significant risk estimates of having a pregnancy-related venous thromboembolism in the presence of the prothrombotic genetic risk factors analyzed suggest to screen for these mutations women with a personal history of thromboembolic events during pregnancy or the postpartum period. (Am J Obstet Gynecol 1998;179:1324-8.)
The purpose of this study was to determine the basal levels of dopamine (DA) and to examine the enzymes involved in DA metabolism in different microdissected nephron segments from rat kidneys. ...Segments were incubated with DA (50 nM) or DA plus monoamine oxidase (MAO) or catechol-O-methyl transferase (COMT) inhibitors. Basal DA levels were higher in the proximal convoluted tubule (PCT, 10.8+/-3.7 pg/mm) and in the medullary collecting duct (MCD, 10.9+/-4.0 pg/mm) than in the medullary thick ascending limb of Henle's loop (MTAL, 4.9+/-0.9 pg/mm) (P<0.05). The percentage of exogenously added DA that was not metabolised was similar in both PCT (67+/-13%) and MCD (65+/-5%) and lower in MTAL (35+/-7%), suggesting that MTAL is a major site of DA metabolism. Inhibition of MAO (pargyline 1 mM) significantly increased the basal content of DA and the percentage of the added non-metabolised DA (to 95+/-10%) in PCT but had no effect on MTAL or MCD. Conversely, inhibition of COMT (nitecapone or Ro-41-0960, both 1 mM) slightly increased the basal levels of DA only in MTAL, whereas the percentage of added DA not metabolised rose to 97+/-10% in MTAL and to 91+/-15% in MCD. COMT inhibition had no effect in PCT. In conscious rats pargyline (50 mg/kg) increased urinary DA from 680+/-34 to 1,128+/-158 ng/d/100 g BW (P<0.01) while nitecapone (40 mg/kg) produced a slight non-significant increment. Our results show that DA is present all along the rat nephron and that renal DA is metabolised continuously and predominantly by MAO in proximal segments, and by COMT in the more distal ones.
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