Hemoglobin and HFE gene polymorphisms in Brazilian populations in regions endemic for malaria

Our objective was to determine how the distribution of red blood cell diseases is related to malaria occurrence in north Brazil, a region endemic for malaria. We evaluated the incidence of two mutations in the HFE gene, H63D and C282Y, in two study groups: a control blood donor group, with no indication of malaria infection, and a group constituted of malaria patients of four states of the Amazonian region. The hemoglobin polymorphisms were obtained by HPLC and classical laboratory methodologies, and the two mutations in the HFE gene were assayed by PCR-RFLP. We found a high frequency of alpha thalassemia, but there were no significant differences between blood donors and malaria patients. There were also no significant differences in the frequencies of HbA(2); however, the frequency of HbF was significantly different in individuals with malaria from Para and Rondonia. The mean number of reticulocytes was significantly reduced in the blood donors from the northern region, suggesting an adaptive strategy of these populations to parasitic attack by Plasmodium. Most individuals were heterozygous for the H63D allele of the HFE gene in both study groups. In the blood donors group, the greatest frequency of the H63D allele was found in Caucasians of all the states. In the malaria patients group in Rondonia, there was a high frequency of the H63D allele among the non-Caucasians. In the other states, and in the malaria patients group, the H63D allele was the most frequent among the Caucasians. Based on our results, we suggest that the maintenance of polymorphism of the mutations in the gene HFE can be explained by selective factors other than malaria, or it is due to simple allelic oscillation and by the constant gene flow among the populations in Brazil.

Validation of hysteroscopic view in cases of endometrial hyperplasia and cancer in patients with abnormal uterine bleeding

STUDY OBJECTIVE: To validate hysteroscopic view with histology in cases of endometrial hyperplasia and cancer in patients with abnormal uterine bleeding (AUB)DESIGN: Retrospective study.(Canadian Task Force classification II-3).SETTING: University teaching hospitals in Rio de Janeiro and São Paulo, and private office in Rio de Janeiro.PATIENTS: Four thousand and fifty-four patients with AUB in whom hysteroscopic views were complete and the histologic result was conclusive.INTERVENTION: Four thousand and fifty-four office hysteroscopies with complete views and conclusive histologic results. The material for histologic examination was obtained through biopsy of the lesion in an outpatient unit or through the resection of the entire lesion in patients who underwent surgery. Histology was considered the gold standard and compared with the hysteroscopic view.MEASUREMENTS AND MAIN RESULTS: In the histology of the 4054 examinations, 613 (15.2%) were endometrial hyperplasia, and 105 (2.6%) were endometrial cancer. The most frequent hysteroscopic finding was endometrial polyps (31.2%). In endometrial hyperplasia, the sensitivity of the hysteroscopic view was 56.3% (95% CI 52.21-60.2%), specificity was 89.1% (95% CI 88.0%-90.1%), positive predictive value (PPV) was 48.0% (95% CI 44.3%-51.7%), negative predictive value (NPV) was 92.0% (95% Cl 90.1%-92.9%), and accuracy was 72.7% (95% CI 70.7%-74.7%). Accuracy was defined as the proportion of correct results among the hysteroscopic examinations. In endometrial cancer, the sensitivity of the hysteroscopic view was 80.0% (95% Cl 71.1%-87.2%), specificity was 99.5% (95% CI 99.2%-99.7%), PPV was 81.5% (95% Cl 72.7%-88.5%), NPV was 99.5% (95% CI 99.2%-99.7%), and accuracy was 89.8% (95% CI, 85.9%-93.6%). In the 814 patients (20.0%) in whom the hysteroscopic view was normal, there were no false negatives for endometrial cancer; however, there were 37 (4.5%) false negatives for endometrial hyperplasia. In the histologic cases of endometrial cancer, 101 (96.2%) hysteroscopic views were compatible with cancer or hyperplasia (80.0% and 16.2%, respectively). Ninety-seven out of 103 hysteroscopic views with cancer findings (94.2%) had histologic diagnosis of cancer or hyperplasia (81.5% and 12.6%, respectively).CONCLUSION: It seems that even in face of good validity of hysteroscopic view for endometrial hyperplasia and cancer, histologic study is mandatory in the presence of any lesion as the hysteroscopic view cannot completely replace the histologic study in patients with AUB. (C) 2006 AAGL. All rights reserved.

REEVALUATION OF CHLORIDES REGULATION OF HEMOGLOBIN OXYGEN-UPTAKE - THE NEGLECTED CONTRIBUTION OF PROTEIN HYDRATION IN ALLOSTERISM

We have measured hemoglobin oxygen uptake vs. The partial pressure of oxygen, with independently controlled activities of chloride and water. This control is effected by combining different concentrations of NaCl and sucrose in the bathing solution to achieve: (i) water activities were varied and CI- activity was fixed, (ii) both water and CI- activities were varied with a traditional NaCI titration, or (iii) CI- activities were varied and water activity was fixed by adding compensating sucrose. Within this analysis, the CI--regulated loading of four oxygens can be described by the reaction Hb.CI- + 4 O-2 + 65 H2O reversible arrow Hb.4O(2).65H(2)O + CI-. The dissociation of a neatly integral chloride, rather than the nonintegral 1.6 chlorides inferred earlier from simple salt titration, demonstrates the need to recognize the potentially large contribution from changes in water activity when titrating weakly binding solutes. The single-chloride result might simplify structural considerations of the action of CI- in hemoglobin regulation.

The role of hydration on the mechanism of allosteric regulation: In situ measurements of the oxygen-linked kinetics of water binding to hemoglobin

We report here the first direct measurements of changes in protein hydration triggered by a functional binding. This task is achieved by weighing hemoglobin (Hb) and myoglobin films exposed to an atmosphere of 98%, relative humidity during oxygenation. The binding of the first oxygen molecules to Hb tetramer triggers a change in protein conformation, which increases binding affinity to the remaining empty sites giving rise to the appearance of cooperative phenomena. Although crystallographic data have evidenced that this structural change increases the protein water-accessible surface area, isobaric osmotic stress experiments in aqueous cosolutions have shown that water binding is linked to Hb oxygenation. Now we show that the differential hydration between fully oxygenated and fully deoxygenated states of these proteins, determined by weighing protein films with a quartz crystal microbalance, agree with the ones determined by osmotic stress in aqueous cosolutions, from the linkage between protein oxygen affinity and water activity. The agreements prove that the changes in water activity brought about by adding osmolytes to the buffer solution shift biochemical equilibrium in proportion to the number of water molecules associated with the reaction. The concomitant kinetics of oxygen and of water binding to Hb have been also determined. The data show that the binding of water molecules to the extra protein surface exposed on the transition from the low-affinity T to the high-affinity R conformations of hemoglobin is the rate-limiting step of Hb cooperative reaction. This evidences that water binding is a crucial step on the allosteric mechanism regulating cooperative interactions, and suggests the possibility that environmental water activity might be engaged in the kinetic control of some important reactions in vivo.

HIGH-TEMPERATURE SUPERFLUIDITY WITH ABNORMAL FERMIONIC OCCUPANCY

We examine a Lipkin based two-level pairing model at finite temperature and in the thermodynamic limit. Whereas at T = 0 the model exhibits a superconducting ground state for sufficiently high values of the coupling constant, a partially superconducting phase in which some of the particles are paired, is found to survive at high temperatures in a special treatment. This phase is a mixture of abnormally-occupied eigenstates, which lie at higher energy, of the interactionless model Hamiltonian.

Seasonal influence on hematologic values and hemoglobin electrophoresis in Brazilian Boa constrictor amarali

As ectothermic animals, snakes depend exclusively on the environment for proper temperature maintenance, which may greatly influence their activity. Twenty-five adult Boa constrictor amarali snakes maintained in captivity were used to determine the influence of seasons on their hematologic values and electrophoretic profile of hemoglobin. A complete blood cell count (CBC) and examination for hemoparasites were performed in the summer and winter of 2004. Hemoglobin was stored for later electrophoresis. Significant differences (P < 0.05) were obtained in RBC, WBC. lymphocyte, thrombocyte, and monocyte counts, demonstrating the importance of the period of the year in the interpretation of reference values in these animals. Two snakes were detected with blood parasites (Hepatozoon sp.) in the winter and four in the summer. although it appears that their presence did not cause any significant alterations in the CBC. The electrophoretic analysis of the samples demonstrated two-four hemoglobin bands in this species.

Comparison of oxidative stress and the frequency of polymorphisms in the HFE gene between hemoglobin S trait blood donors and sickle cell disease patients

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

On the stability of the extracellular hemoglobin of Glossoscolex paulistus, in two iron oxidation states, in the presence of urea

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

An improved electrophoretic method for a screening program for haemoglobinopathies

A method for a screening program for haemoglobinopathies in a starch agar gel mixed with saponin is presented. Normal and abnormal blood containing haemoglobins S, C, I, M Boston, D Punjab, beta thalassaemia major and beta thalassaemia minor, were applied, in a tray with the capacity for 100 samples. The electrophoresis was performed in 45 min using 300 V. This method offers special advantages for the examination of a large number of samples, using a small amount of whole blood and without the previous preparation of haemoglobin solution.