The Bambuí health and ageing study (BHAS): methodological approach and preliminary results of a population-based cohort study of the elderly in Brazil

OBJECTIVE: A cohort study has been designed to identify predictors of adverse health events in the elderly. The methodology of the study and preliminary descriptive results are presented. METHODS: The study population comprises all residents of Bambuí (Minas Gerais, Brazil), aged 60 or more years (n=1.742). From these, 92.2% were interviewed and 85.9% underwent clinical examination, consisting of haematological and biochemical tests, serology for Trypanosoma cruzi, anthropometric and blood pressure measures and electrocardiogram. Aliquots of serum, plasma and DNA were stored for future investigations. The baseline interview included sociodemographic characteristics, self-referred health condition and history of selected diseases, medication use, health service use, source of medical care, physical activities, smoking, drinking and eating habits, reproductive history, physical functioning, life events, social support and mental health. Individuals are being followed up annually. RESULTS: The following characteristics predominated among participants: women (60,0%), married (48.9%) or widowed (35.4%), people living in households with up to 2 residents (73.8%), heads of family (76.7%), people with monthly income between 1.00 and 2.99 Brazilian minimum wages (62.0%) and people with up to 4 years of schooling (89.1%). The median age was 68 years. Among the cohort members, only 1.7% were lost in the first follow-up. CONCLUSIONS: In general, the characteristics of the study population were very similar to those from other epidemiological studies of the elderly based on large Brazilian cities. The small number of losses to follow-up indicates that the choice of Bambuí was adequate, assuring the feasibility of a long term cohort study.

Active immunization against hepatitis B virus (HBV) with low-doses of plasma-derived vaccine by intradermal route

Schedule for vaccination against HBV infection has usually been based on three separate injections of 20 meg of the vaccine by intramuscular route. One of the main shortcomings to its use in large scale programs has been its high cost. Ninety out of 300 health workers were submitted to three injections of 2 meg of plasma-derived vaccine (PDV) by intradermal (ID) route on days 0, 30, and 180. Anti-HBs was detected in 74 (82.2%) after the second dose and in 80 (88.9%) after the third dose, a non-significant difference. However, levels above 10 times the cut-off were observed in 29 (32.2%) and 77 (85.5%), respectively (p < 0.001). The results showed that a low-dose schedule is effective when used in health workers and should be tried with other risk groups.

Relationship between plasma creatinine concentration and glomerular filtration in preterm newborn infants

Fluid management and dosage regimens of drugs in preterm infants should be based on the glomerular filtration rate. The current methods to determine glomerular flitration rate are invasive, time-consuming, and expensive. In contrast, creatinine clearance can be easy obtained and quickly determined. The purpose of this study was to compare plasma creatinine on the third and seventh day of life in preterm newborn infants, to evaluate the influence of maternal creatinine, and to demonstrate creatinine clearance can be used as a reliable indicator of glomerular filtration rate. We developed a prospective study (1994) including 40 preterm newborns (gestational age < 37 weeks), average = 34 weeks; birth weight (average) = 1840 g, in the first week of life. Inclusion criteria consisted of: absence of renal and urinary tract anomalies; O2 saturation 3 92%; adequate urine output (>1ml/kg/hr); normal blood pressure; absence of infections and no sympathomimetic amines in use. A blood sample was collected to determine plasma creatinine (enzymatic method) on the third and seventh day of life and creatinine clearance (CrCl) was obtained using the following equation: , k = 0.33 in preterm infant All plasma creatinine determinations showed normal values [third day: 0.78 mg/dl ± 0.24 (mean ± SD)and seventh day: 0.67 mg/dl ± 0.31 - (p>0.05)]. Also all creatinine clearance at third and seventh day of life were normal [third day: 19.5 ml/min ± 5.2 (mean ± SD) and seventh day: 23.8 ml/min ± 7.3 - (p>0,05)]. All preterm infants developed adequate renal function for their respective gestational age. In summary, our results indicate that, for clinical practice, the creatinine clearance, using newborn length, can be used to estimate glomerular filtration rate in preterm newborn infants.

Cytokines and visceral leishmaniasis: a comparison of plasma cytokine profiles between the clinical forms of visceral leishmaniasis

It is not well established whether cytokine production differs in response to different clinical forms of visceral leishmaniasis (VL). In this work, we performed a cross-sectional study to investigate the plasma levels of cytokines [interferon (IFN)-γ, tumour necrosis factor (TNF)-α, interleukin (IL)-2, IL-4, IL-10 and IL-12] involved in the pathogenesis of VL in 80 subjects from VL endemic areas, including subjects with active VL, subjects with asymptomatic infection, subjects with cured VL and uninfected controls. The patients were recruited by sampling from a referral hospital and by random selection from a population-based cohort study. The results showed significant differences in the plasma concentration of all cytokines between the groups (p < 0.05). Patients with the active disease had higher plasma levels of IL-10, IL-4, INF-γ and TNF-α relative to the other groups and they produced more IL-12 than asymptomatic and cured subjects. Only the IL-2 concentration was higher in the asymptomatic and cured subjects relative to the patients with active disease (p < 0.05). Our results suggest that these cytokines can be used as markers in epidemiological studies conducted in endemic areas to distinguish between different clinical forms of VL. However, their usefulness should be confirmed in investigations conducted in other endemic areas.

Optimisation of a quantitative polymerase chain reaction-based strategy for the detection and quantification of human herpesvirus 6 DNA in patients undergoing allogeneic haematopoietic stem cell transplantation

Human herpesvirus 6 (HHV-6) may cause severe complications after haematopoietic stem cell transplantation (HSCT). Monitoring this virus and providing precise, rapid and early diagnosis of related clinical diseases, constitute essential measures to improve outcomes. A prospective survey on the incidence and clinical features of HHV-6 infections after HSCT has not yet been conducted in Brazilian patients and the impact of this infection on HSCT outcome remains unclear. A rapid test based on real-time quantitative polymerase chain reaction (qPCR) has been optimised to screen and quantify clinical samples for HHV-6. The detection step was based on reaction with TaqMan® hydrolysis probes. A set of previously described primers and probes have been tested to evaluate efficiency, sensitivity and reproducibility. The target efficiency range was 91.4% with linearity ranging from 10-106 copies/reaction and a limit of detection of five copies/reaction or 250 copies/mL of plasma. The qPCR assay developed in the present study was simple, rapid and sensitive, allowing the detection of a wide range of HHV-6 loads. In conclusion, this test may be useful as a practical tool to help elucidate the clinical relevance of HHV-6 infection and reactivation in different scenarios and to determine the need for surveillance.

Identificação de resíduos de disparos de armas de fogo por meio da técnica de espectrometria de massas de alta resolução com fonte de plasma indutivo

The violence derived from crimes involving firearms represents one of the main concerns of society. For this reason modern techniques have emerged in forensic science to identify suspects at crime scenes. This work describes a methodology to identify residues present in the hands of suspect by using a high resolution inductively coupled plasma mass spectrometry and collection procedure based on ethylenediaminetetraacetic acid (EDTA) solution as a complexing agent in moistened swabs. In order to distinguish real gunshot residues from others types of residues present in the hand of suspect, ternary ratio per cent diagrams were developed for antimony (Sb), barium (Ba) and lead (Pb) detected on the hands of volunteers, before and immediately after shooting tests, revealing a remarkable difference in both situations.

Use of thin films obtained by plasma polymerization for grain protection and germination enhancement

In this work, preliminary results of the use of hydrophobic thin films obtained by plasma deposition to protect grains and seeds are presented: grains coated by the films did not present biological degradation when stored in a saturated water vapor environment, but had their germination accelerated in the presence of water. A model that explains the difference of behavior of the films when exposed to water in vapor form or in liquid form, based on the formation of microchannels within the film that lead to water uptake in seeds, is presented. The model was successfully tested using quartz crystal measurements, which showed that the microchannels within the films can favor the adsorption and permeation of water when the films are immersed in water.

Pré-concentração de cádmio com Saccharomyces cerevisiae e determinação em águas fluviais usando espectrometria de emissão óptica com plasma indutivamente acoplado

A preconcentration method based on the use of Saccharomyces cerevisiae as sorbent material is proposed for the determination of Cd(II) in river water. The solid phase extraction was performed in batch mode and the determination of the analyte in the solid phase was easily carried out by introducing a slurry of the yeast (0.0625 g / 2.5 mL) directly into the ICP OES. A limit of detection of 0.11 µg L-1 and a sample throughput in the range of 4 - 54 sample h-1 were obtained. Determinations of cadmium in a certified sample and in real river water samples were in excellent agreement with the expected values.

Determinação de resíduos de pesticidas em plasma bovino por cromatografia gasosa-espectrometria de massas

An analytical method for the isolation based on matrix solid-phase dispersion technique and gas chromatographic determination of pesticides in cattle plasma is presented. It was fortified 0.25 g of plasma with pesticides and blended with 1 g each C18 and Na2SO4. The homogenized matter was transferred to a SPE cartridge, which contained 1 g of activated florisil with 5 mL acetonitrile. The analites were eluted under vaccum with 15 mL acetonitrile, the extract was analyzed by gas chromatography-mass spectrometry. The limit of quantification of the method was 0.04 mg L-1 for chlorphenvinfos and fipronil and 0.02 mg L-1 for cypermethrin..

BIOORGANIC CONCEPTS INVOLVED IN THE DETERMINATION OF GLUCOSE, CHOLESTEROL AND TRIGLYCERIDES IN PLASMA USING THE ENZYMATIC COLORIMETRIC METHOD

Bioorganic and biological chemistry have been found to be highly motivating to undergraduate students and in this context, biochemical blood parameter analysis emerges as highly attractive content. In this proposal, several aspects related to analyses of glucose, cholesterol and triglycerides using the enzymatic colorimetric method were involved, and the findings have at least two relevant implications: i) introducing students to connections between organic chemistry and biology based on enzymatic processes, including reactivity and mechanistic aspects; ii) performing a micro scale bioassay analysis. The proposal requires two theoretical classes (2 h per class) and one practical class (4 h).

A NOVEL METHOD FOR THE DETERMINATION OF TRACE THORIUM BY DISPERSIVE LIQUID-LIQUID MICROEXTRACTION BASED ON SOLIDIFICATION OF FLOATING ORGANIC DROP

In this study, dispersive liquid-liquid microextraction based on the solidification of floating organic droplets was used for the preconcentration and determination of thorium in the water samples. In this method, acetone and 1-undecanol were used as disperser and extraction solvents, respectively, and the ligand 1-(2-thenoyl)-3,3,3-trifluoracetone reagent (TTA) and Aliquat 336 was used as a chelating agent and an ion-paring reagent, for the extraction of thorium, respectively. Inductively coupled plasma-optical emission spectrometry was applied for the quantitation of the analyte after preconcentration. The effect of various factors, such as the extraction and disperser solvent, sample pH, concentration of TTA and concentration of aliquat336 were investigated. Under the optimum conditions, the calibration graph was linear within the thorium content range of 1.0-250 µg L-1 with a detection limit of 0.2 µg L-1. The method was also successfully applied for the determination of thorium in the different water samples.

A simple HPLC-fluorescence method for the measurement of R,S-sotalol in the plasma of patients with life-threatening cardiac arrhythmias

R,S-sotalol, a ß-blocker drug with class III antiarrhythmic properties, is prescribed to patients with ventricular, atrial and supraventricular arrhythmias. A simple and sensitive method based on HPLC-fluorescence is described for the quantification of R,S-sotalol racemate in 500 µl of plasma. R,S-sotalol and its internal standard (atenolol) were eluted after 5.9 and 8.5 min, respectively, from a 4-micron C18 reverse-phase column using a mobile phase consisting of 80 mM KH2PO4, pH 4.6, and acetonitrile (95:5, v/v) at a flow rate of 0.5 ml/min with detection at lex = 235 nm and lem = 310 nm, respectively. This method, validated on the basis of R,S-sotalol measurements in spiked blank plasma, presented 20 ng/ml sensitivity, 20-10,000 ng/ml linearity, and 2.9 and 4.8% intra- and interassay precision, respectively. Plasma sotalol concentrations were determined by applying this method to investigate five high-risk patients with atrial fibrillation admitted to the Emergency Service of the Medical School Hospital, who received sotalol, 160 mg po, as loading dose. Blood samples were collected from a peripheral vein at zero, 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0, 8.0, 12.0 and 24.0 h after drug administration. A two-compartment open model was applied. Data obtained, expressed as mean, were: CMAX = 1230 ng/ml, TMAX = 1.8 h, AUCT = 10645 ng h-1 ml-1, Kab = 1.23 h-1, a = 0.95 h-1, ß = 0.09 h-1, t(1/2)ß = 7.8 h, ClT/F = 3.94 ml min-1 kg-1, and Vd/F = 2.53 l/kg. A good systemic availability and a fast absorption were obtained. Drug distribution was reduced to the same extent in terms of total body clearance when patients and healthy volunteers were compared, and consequently elimination half-life remained unchanged. Thus, the method described in the present study is useful for therapeutic drug monitoring purposes, pharmacokinetic investigation and pharmacokinetic-pharmacodynamic sotalol studies in patients with tachyarrhythmias.

Association of apolipoprotein E polymorphism with plasma lipids and Alzheimer's disease in a Southern Brazilian population

Apolipoprotein E (protein: apo E; gene: APOE) plays an important role in the multifactorial etiology of both Alzheimer's disease (AD) and lipid level concentrations. The polymerase chain reaction (PCR) was used to investigate the APOE gene polymorphism in 446 unrelated Caucasians, among them 23 AD patients, and 100 Afro-Brazilians living in Porto Alegre, Brazil. The frequencies of the APOE*2, APOE*3 and APOE*4 alleles were 0.075, 0.810 and 0.115 in Caucasians and 0.075, 0.700 and 0.225 in Afro-Brazilians, respectively (c2 = 8.72, P = 0.013). A highly significant association was observed between the APOE*4 allele and AD in this population-based sample. The APOE*4 frequency in AD patients (39%) was about four times higher than in the general Caucasian population (11.5%). The influence of each of the three common APOE alleles on lipid traits was evaluated by the use of the average excess statistic. The E*2 allele is associated with lower levels of triglycerides and of total and non-HDL cholesterol in both men and women. Conversely, the E*4 allele is associated with higher levels of these traits in women only. The effect of APOE alleles was of greater magnitude in women.

Paradoxical sleep deprivation increases plasma endothelin levels

The endothelins (ET-1, 2 and 3) constitute a family of 21 amino acid peptides with potent biological activities. ET-1 is one of the most potent endogenous vasoconstrictors so far identified and its increased concentration in plasma appears to be closely related to the pathogenesis of arterial hypertension as well as to obstructive sleep apnea (OSA). OSA patients exhibit repetitive episodes of apnea and hypopnea that result in hypoxia and consecutive arousals. These patients are chronically sleep deprived, which may aggravate the hypertensive features, since literature data show that sleep deprivation results in hypertension both in humans and in animals. Based on the reported relationship between ET-1, hypertension and sleep deprivation consequences, the purpose of the present study was to determine plasma ET concentrations in paradoxical sleep-deprived animals. Male Wistar rats, 3 to 4 months old (N = 10 per group), were deprived of sleep for 24 and 96 h by the platform technique and plasma ET-1/2 was measured by radioimmunoassay. Analysis of plasma revealed that 96 h of sleep deprivation induced a significant increase in ET-1/2 release (6.58 fmol/ml) compared to control (5.07 fmol/ml). These data show that sleep deprivation altered plasma ET-1/2 concentrations, suggesting that such an increase may participate in the genesis of arterial hypertension and cardiorespiratory changes observed after sleep deprivation.

Specific alterations in plasma proteins during depressed, manic, and euthymic states of bipolar disorder

Bipolar disorder (BD) is a common psychiatric mood disorder affecting more than 1-2% of the general population of different European countries. Unfortunately, there is no objective laboratory-based test to aid BD diagnosis or monitor its progression, and little is known about the molecular basis of BD. Here, we performed a comparative proteomic study to identify differentially expressed plasma proteins in various BD mood states (depressed BD, manic BD, and euthymic BD) relative to healthy controls. A total of 10 euthymic BD, 20 depressed BD, 15 manic BD, and 20 demographically matched healthy control subjects were recruited. Seven high-abundance proteins were immunodepleted in plasma samples from the 4 experimental groups, which were then subjected to proteome-wide expression profiling by two-dimensional electrophoresis and matrix-assisted laser desorption/ionization-time-of-flight/time-of-flight tandem mass spectrometry. Proteomic results were validated by immunoblotting and bioinformatically analyzed using MetaCore. From a total of 32 proteins identified with 1.5-fold changes in expression compared with healthy controls, 16 proteins were perturbed in BD independent of mood state, while 16 proteins were specifically associated with particular BD mood states. Two mood-independent differential proteins, apolipoprotein (Apo) A1 and Apo L1, suggest that BD pathophysiology may be associated with early perturbations in lipid metabolism. Moreover, down-regulation of one mood-dependent protein, carbonic anhydrase 1 (CA-1), suggests it may be involved in the pathophysiology of depressive episodes in BD. Thus, BD pathophysiology may be associated with early perturbations in lipid metabolism that are independent of mood state, while CA-1 may be involved in the pathophysiology of depressive episodes.