Variations in weed population densities, rate of change and community diversity in RR-soybeans and RR-maize strip crops under two herbicide strategies

Concerns about the sustainability of large-scale, direct-drilled RR-soybeans (Glycine max), and RR-maize (Zea mays) under monoculture in central Argentina are growing steadily. An experiment was conducted during three consecutive years to determine the effects of crops and systems (monocultures and strips) and herbicide strategy on weed density, population rate of change (l), b community diversity (H´), crop yields and Land Equivalent Ratio (LER). Not only crops but also crop systems differentially influenced weed densities along their growth and development. For crop harvests, weed densities increased in both maize crop systems as compared to in the one for soybeans, but the lowest increase occurred in soybean strips. Differences were leveled by both herbicide strategies, which achieved 73% efficacy during the critical periods in both crops. l of annual monocotyledonous increased, thus shifting the weed community composition. Species richness and H´ were not affected by crop systems, but both herbicide strategies, particularly POST, either in soybeans in monoculture or in maize strips, significantly enhanced H´. Crop yields significantly increased in the maize-strip system with POST (Year 1) or PRE (Years 2 and 3) strategies, thus increasing LER above 1. Herbicide Environmental Load treatments fall within very low or low field use rating.

Familial predisposition to hypertension and the association between urinary sodium excretion and blood pressure in a population-based sample of young adults

The reasons for the inconsistent association between salt consumption and blood pressure levels observed in within-society surveys are not known. A total of 157 normotensive subjects aged 18 to 35 years, selected at random in a cross-sectional population-based survey, answered a structured questionnaire. They were classified as strongly predisposed to hypertension when two or more first-degree relatives had a diagnosis of hypertension. Anthropometric parameters were obtained and sitting blood pressure was determined with aneroid sphygmomanometers. Sodium and potassium excretion was measured by flame spectrophotometry in an overnight urine sample. A positive correlation between blood pressure and urinary sodium excretion was detected only in the group of individuals strongly predisposed to hypertension, both for systolic blood pressure (r = 0.51, P<0.01) and diastolic blood pressure (r = 0.50, P<0.01). In a covariance analysis, after controlling for age, skin color and body mass index, individuals strongly predisposed to hypertension who excreted amounts of sodium above the median of the entire sample had higher systolic and diastolic blood pressure than subjects classified into the remaining conditions. The influence of familial predisposition to hypertension on the association between salt intake and blood pressure may be an additional explanation for the weak association between urinary sodium excretion and blood pressure observed in within-population studies, since it can influence the association between salt consumption and blood pressure in some but not all inhabitants.

Acute myeloid leukemia in elderly patients: experience of a single center

Acute myeloid leukemia (AML) is a disease predominantly of older adults. Treatment of AML in the elderly is complicated not only by comorbidities but also by the high prevalence of poor prognosis markers. Thirty-one consecutive unselected patients with AML older than 60 years (representing 33% of all AML cases diagnosed at our institution during the same period) were followed over a period of 5 years (1997-2002). A high incidence of AML with multilineage dysplasia (45%) and no favorable cytogenetic abnormalities but 62% intermediate and 38% unfavorable karyotypes were found. Sixteen patients (52%) were selected for induction of intensive cytotoxic treatment and complete remission was achieved only by some of these intensively treated patients (7 of 16). Of these, 3 remained alive without disease (median: 11 months), 1 patient died shortly after complete remission, and 3 patients relapsed and died from refractory disease. Only 1 patient that was refractory to intensive cytotoxic treatment remained alive with disease under supportive care. Fifteen patients (48%) were managed with palliative/supportive care: 7 received palliative treatment and supportive care, 8 received supportive care only, and 4 patients remained alive with disease under supportive care (median: 9 months). Mortality rate was 74% and overall survival at two years was 12%. To the best of our knowledge, there is no previous report regarding elderly patients with AML in Brazilian subsets. The present data are similar to previously reported studies showing that elderly AML patients are not only older but also biologically distinct from younger AML patients, particularly in terms of the high incidence of poor prognostic karyotypes and resistance to therapy.

Headache complaints associated with psychiatric comorbidity in a population-based sample

The objective of the present study was to determine the frequency at which people complain of any type of headache, and its relationship with sociodemographic characteristics and psychiatric comorbidity in São Paulo, Brazil. A three-step cluster sampling method was used to select 1,464 subjects aged 18 years or older. They were mainly from families of middle and upper socioeconomic levels living in the catchment area of Instituto de Psiquiatria. However, this area also contains some slums and shantytowns. The subjects were interviewed using the Brazilian version of the Composite International Diagnostic Interview version 1.1. (CIDI 1.1) by a lay trained interviewer. Answers to CIDI 1.1 questions allowed us to classify people according to their psychiatric condition and their headaches based on their own ideas about the nature of their illness. The lifetime prevalence of "a lot of problems with" headache was 37.4% (76.2% of which were attributed to use of medicines, drugs/alcohol, physical illness or trauma, and 23.8% attributed to nervousness, tension or mental illness). The odds ratio (OR) for headache among participants with "nervousness, tension or mental illness" was elevated for depressive episodes (OR, 2.1; 95%CI, 1.4-3.4), dysthymia (OR, 3.4; 95%CI, 1.6-7.4) and generalized anxiety disorder (OR, 4.3; 95%CI, 2.1-8.6), when compared with patients without headache. For "a lot of problems with" headaches attributed to medicines, drugs/alcohol, physical illness or trauma, the risk was also increased for dysthymia but not for generalized anxiety disorder. These data show a high association between headache and chronic psychiatric disorders in this Brazilian population sample.

Cardiovascular risk factors in a population of Brazilian schoolchildren

Epidemiological and clinical evidence suggests that a judicious diet, regular physical activity and blood pressure (BP) monitoring must start in early childhood to minimize the impact of modifiable cardiovascular risk factors. This study was designed to evaluate BP and metabolic parameters of schoolchildren from Vitória, Espírito Santo State, Brazil, and correlate them with cardiovascular risk factors. The study was conducted on 380 students aged 10-14 years (177 boys, 203 girls) enrolled in public schools. Baseline measurements included body mass index, BP and heart rate. The students were submitted to exercise spirometry on a treadmill. VO2max was obtained from exercise testing to voluntary exhaustion. Fasting serum total cholesterol (TC), LDL-C, HDL-C, triglycerides (TG), and glucose were measured. Nine point nine percent of the boys and 11.7% of the girls were hypertensive or had pre-hypertensive levels. There was no significant correlation between VO2max and TC, LDL-C, or TG in prepubertal children, but a slight negative correlation was detected in post-pubertal boys for HDL-C and TG. In addition, children with hypertension (3.4%) or pre-hypertensive levels (6.6%) also had comorbidity for overweight and blood lipid abnormalities (14% for triglycerides, 44.7% for TC, 25.9% for LDL-C, 52% for low HDL-C). The present study shows for the first time high correlations between prehypertensive blood pressure levels and the cardiovascular risk factors high TC, high LDL-C, low HDL-C in schoolchildren. These are important for the formulation of public health policies and strategies.

The association of ACE gene D/I polymorphism with cardiovascular risk factors in a population from Rio de Janeiro

Our aim was to determine the frequencies of the angiotensin-converting enzyme (ACE) gene alleles D and I and any associations to cardiovascular risk factors in a population sample from Rio de Janeiro, Brazil. Eighty-four adults were selected consecutively during a 6-month period from a cohort subgroup of a previous large cross-sectional survey in Rio de Janeiro. Anthropometric data and blood pressure measurements, echocardiogram, albuminuria, glycemia, lipid profile, and ACE genotype and serum enzyme activity were determined. The frequency of the ACE*D and I alleles in the population under study, determined by PCR, was 0.59 and 0.41, respectively, and the frequencies of the DD, DI, and II genotypes were 0.33, 0.51, and 0.16, respectively. No association between hypertension and genotype was detected using the Kruskal-Wallis method. Mean plasma ACE activity (U/mL) in the DD (N = 28), DI (N = 45) and II (N = 13) groups was 43 (in males) and 52 (in females), 37 and 39, and 22 and 27, respectively; mean microalbuminuria (mg/dL) was 1.41 and 1.6, 0.85 and 0.9, and 0.6 and 0.63, respectively; mean HDL cholesterol (mg/dL) was 40 and 43, 37 and 45, and 41 and 49, respectively, and mean glucose (mg/dL) was 93 and 108, 107 and 98, and 85 and 124, respectively. A high level of ACE activity and albuminuria, and a low level of HDL cholesterol and glucose, were found to be associated with the DD genotype. Finally, the II genotype was found to be associated with variables related to glucose intolerance.

Acute exercise performed close to the anaerobic threshold improves cognitive performance in elderly females

The objective of the present study was to compare the effect of acute exercise performed at different intensities in relation to the anaerobic threshold (AT) on abilities requiring control of executive functions or alertness in physically active elderly females. Forty-eight physically active elderly females (63.8 ± 4.6 years old) were assigned to one of four groups by drawing lots: control group without exercise or trial groups with exercise performed at 60, 90, or 110% of AT (watts) and submitted to 5 cognitive tests before and after exercise. Following cognitive pretesting, an incremental cycle ergometer test was conducted to determine AT using a fixed blood lactate concentration of 3.5 mmol/L as cutoff. Acute exercise executed at 90% of AT resulted in significant (P < 0.05, ANOVA) improvement in the performance of executive functions when compared to control in 3 of 5 tests (verbal fluency, Tower of Hanoi test (number of movements), and Trail Making test B). Exercising at 60% of AT did not improve results of any tests for executive functions, whereas exercise executed at 110% of AT only improved the performance in one of these tests (verbal fluency) compared to control. Women from all trial groups exhibited a remarkable reduction in the Simple Response Time (alertness) test (P = 0.001). Thus, physical exercise performed close to AT is more effective to improve cognitive processing of older women even if conducted acutely, and using a customized exercise prescription based on the anaerobic threshold should optimize the beneficial effects.

Salt and insulin sensitivity after short and prolonged high salt intake in elderly subjects

Salt sensitivity and insulin resistance are correlated with higher cardiovascular risk. There is no information about changes in salt sensitivity (SS) and insulin sensitivity (IS) after a chronic salt overload in humans. The aim of this study was to evaluate these parameters in the elderly. Seventeen volunteers aged 70.5 ± 5.9 years followed a low-salt diet (LSD) for 1 week and a high-salt diet (HSD) for 13 weeks. We evaluated SS after one week (HSD1) and after 13 weeks (HSD13), and subjects’ IS and lipids on their usual diet (UD) at HSD1, and at HSD13. Blood pressure (BP) was measured at each visit and ambulatory blood pressure monitoring (ABPM) was performed twice. SS was the same at HSD1 and HSD13. Systolic BP was lower on LSD than on UD (P = 0.01), HSD1 (P < 0.01) and HSD13 (P < 0.01). When systolic and diastolic BP were evaluated by ABPM, they were higher at HSD13 during the 24-h period (P = 0.03 and P < 0.01) and during the wakefulness period (P = 0.02 and P < 0.01) compared to the UD. Total cholesterol was higher (P = 0.04) at HSD13 than at HSD1. Glucose and homeostasis model assessment (HOMA) were lower at HSD1 (P = 0.02 and P = 0.01) than at HSD13. Concluding, the extension of HSD did not change the SS in an elderly group. The higher IS found at HSD1 did not persist after a longer HSD. A chronic HSD increased BP as assessed by ABPM.

Effects of 174 G/C polymorphism in the promoter region of the interleukin-6 gene on plasma IL-6 levels and muscle strength in elderly women

We investigated the effect of -174 G/C single-nucleotide polymorphism in the promoter region of the IL6 gene on plasma IL-6 levels and muscle strength, and the relationship between IL-6 levels and muscle strength in elderly women. The sample consisted of 199 elderly residents (73.0 ± 7.8 years old) from rest homes and the community in Belo Horizonte, MG, Brazil. -174 G/C polymorphism was determined by direct sequencing of the product by PCR, and plasma IL-6 concentrations were measured by ELISA. Muscle strength in the knee joint was evaluated using a Biodex System 3 Pro® isokinetic dynamometer. ANCOVA was used to determine the effect of polymorphism on IL-6 levels and muscle strength, and the Pearson correlation coefficient to assess the relationship between IL-6 levels and muscle strength. -174 G/C polymorphism was associated with the plasma IL-6 levels of elderly women (P < 0.01) since homozygotes for the G allele showed high IL-6 levels (GG 3.85 pg/mL, GC + CC 2.13 pg/mL). There was no association of polymorphism on muscle strength (P > 0.05). No association was found between IL-6 levels and knee extensor muscle (r = 0.087, P = 0.306) or flexor (r = -0.011, P = 0.894) strength. An interaction between -174 G/C polymorphism and housing conditions of the sample of elderly women was identified, with the effect of genotype on IL-6 levels being higher in the institutionalized elderly. These results support the evidence that -174 G/C polymorphism of the IL6 gene associates with individual variability of plasma IL-6 levels in elderly women.

Strength and power training did not modify cardiovascular responses to aerobic exercise in elderly subjects

Resistance training increases muscle strength in older adults, decreasing the effort necessary for executing physical tasks, and reducing cardiovascular load during exercise. This hypothesis has been confirmed during strength-based activities, but not during aerobic-based activities. This study determined whether different resistance training regimens, strength training (ST, constant movement velocity) or power training (PT, concentric phase performed as fast as possible) can blunt the increase in cardiovascular load during an aerobic stimulus. Older adults (63.9 ± 0.7 years) were randomly allocated to: control (N = 11), ST (N = 13, twice a week, 70-90% 1-RM) and PT (N = 15, twice a week, 30-50% 1-RM) groups. Before and after 16 weeks, oxygen uptake (VO2), systolic blood pressure (SBP), heart rate (HR), and rate pressure product (RPP) were measured during a maximal treadmill test. Resting SBP and RPP were similarly reduced in all groups (combined data = -5.7 ± 1.2 and -5.0 ± 1.7%, respectively, P < 0.05). Maximal SBP, HR and RPP did not change. The increase in measured VO2, HR and RPP for the increment in estimated VO2 (absolute load) decreased similarly in all groups (combined data = -9.1 ± 2.6, -14.1 ± 3.9, -14.2 ± 3.0%, respectively, P < 0.05), while the increments in the cardiovascular variables for the increase in measured VO2 did not change. In elderly subjects, ST and PT did not blunt submaximal or maximal HR, SBP and RPP increases during the maximal exercise test, showing that they did not reduce cardiovascular stress during aerobic tasks.

Comparison of the variability of the onset and recovery from neuromuscular blockade with cisatracurium versus rocuronium in elderly patients under total intravenous anesthesia

This study was designed to compare the variability of the onset and offset of the effect of two neuromuscular blocking drugs with different elimination pathways in adult and elderly patients during total intravenous anesthesia (TIVA). After Ethics Committee approval and patients’ informed consent, the drugs were compared in 40 adult and 40 elderly patients scheduled for elective surgery under TIVA with tracheal intubation who were randomized to receive a single bolus dose of 0.15 mg/kg cisatracurium or 0.9 mg/kg rocuronium. The time of onset of maximum depression, duration of action, and recovery index time were measured and recorded for each patient and variability is reported as means ± standard deviation. Time of onset was significantly shorter for rocuronium than cisatracurium for the adult and elderly groups (P = 0.000), but the variability of cisatracurium was significantly greater compared with rocuronium for the same age groups (93.25 vs 37.01 s in the adult group and 64.56 vs 33.75 s in the elderly group; P = 0.000). The duration of the effect in the elderly group receiving rocuronium was significantly longer than in the elderly group receiving cisatracurium, and the variability of the duration was significantly greater in the rocuronium group than in the cisatracurium group. Mean time of recovery was significantly longer for the elderly group receiving rocuronium than for the elderly group receiving cisatracurium (P = 0.022), and variability was also greater (P = 0.002). Both drugs favored good intubating conditions. In conclusion, cisatracurium showed less variability in these parameters than rocuronium, especially in the elderly, a fact that may be of particular clinical interest.

Whole-body vibration decreases the proliferativeb response of TCD4+ cells in elderly individuals with knee osteoarthritis

The aim of this study was to investigate the effect of adding whole-body vibration (WBV; frequency = 35 to 40 Hz; amplitude = 4 mm) to squat training on the T-cell proliferative response of elderly patients with osteoarthritis (OA) of the knee. This study was a randomized controlled trial in which the selected variables were assessed before and after 12 weeks of training. Twenty-six subjects (72 ± 5 years of age) were divided into three groups: 1) squat training with WBV (WBV, N = 8); 2) squat training without WBV (N = 10), and 3) a control group (N = 8). Women who were ≥60 years of age and had been diagnosed with OA in at least one knee were eligible. The intervention consisted of 12 uninterrupted weeks of squatting exercise training performed 3 times/week. Peripheral blood mononuclear cells were obtained from peripheral blood collected before and after training. The proliferation of TCD4+ and TCD8+ cells was evaluated by flow cytometry measuring the carboxyfluorescein succinimidyl ester fluorescence decay before and after the intervention (∆). The proliferative response of TCD4+ cells (P = 0.02, effect size = 1.0) showed a significant decrease (23%) in the WBV group compared to the control group, while there was no difference between groups regarding the proliferative response of TCD8+ cells (P = 0.12, effect size = 2.23). The data suggest that the addition of WBV to squat exercise training might modulate T-cell-mediated immunity, minimizing or slowing disease progression in elderly patients with OA of the knee.

Frequency of Werner helicase 1367 polymorphism and age-related morbidity in an elderly Brazilian population

Werner syndrome (WS) is a premature aging disease caused by a mutation in the WRN gene. The gene was identified in 1996 and its product acts as a DNA helicase and exonuclease. Some specific WRN polymorphic variants were associated with increased risk for cardiovascular diseases. The identification of genetic polymorphisms as risk factors for complex diseases affecting older people can improve their prevention, diagnosis and prognosis. We investigated WRN codon 1367 polymorphism in 383 residents in a district of the city of São Paulo, who were enrolled in an Elderly Brazilian Longitudinal Study. Their mean age was 79.70 ± 5.32 years, ranging from 67 to 97. This population was composed of 262 females (68.4%) and 121 males (31.6%) of European (89.2%), Japanese (3.3%), Middle Eastern (1.81%), and mixed and/or other origins (5.7%). There are no studies concerning this polymorphism in Brazilian population. These subjects were evaluated clinically every two years. The major health problems and morbidities affecting this cohort were cardiovascular diseases (21.7%), hypertension (83.7%), diabetes (63.3%), obesity (41.23%), dementia (8.0%), depression (20.0%), and neoplasia (10.8%). Their prevalence is similar to some urban elderly Brazilian samples. DNA was isolated from blood cells, amplified by PCR and digested with PmaCI. Allele frequencies were 0.788 for the cysteine and 0.211 for the arginine. Genotype distributions were within that expected for the Hardy-Weinberg equilibrium. Female gender was associated with hypertension and obesity. Logistic regression analysis did not detect significant association between the polymorphism and morbidity. These findings confirm those from Europeans and differ from Japanese population.

Apolipoprotein E polymorphism distribution in an elderly Brazilian population: the Bambuí Health and Aging Study

Apolipoprotein E (ApoE) is one of the most extensively studied genes in the context of aging, but there are few population-based studies on ApoE polymorphism in the elderly in developing countries. The objective of the present study was to assess ApoE allele and genotype distribution in a large elderly community-based sample and its association with age, sex and skin color. Participants included 1408 subjects (80.8% of all residents aged ³60 years) residing in Bambuí city, MG, Brazil. The DNA samples were subjected to the polymerase chain reaction amplification, followed by the restriction fragment length polymorphism technique, with digestion by HhaI. Analysis was carried out taking into consideration the six ApoE genotypes (e3/e3, e3/e4, e2/e3, e4/e4, e2/e4, and e2/e2), the three ApoE alleles, and the number of ApoE4 alleles for each individual. The e3 allele predominated (80.0%), followed by e4 (13.5%) and e2 (6.5%). All six possible genotypes were observed, the e3/e3 genotype being the most frequent (63.4%). This distribution was similar to that described in other western populations. Sex was not associated with number of ApoE4 alleles. Black skin color was significantly and independently associated with the presence of two ApoE4 alleles (age-sex adjusted OR = 7.38; 95%CI = 1.93-28.25), showing that the African-Brazilian elderly have a high prevalence of the e4 allele, as observed in blacks from Africa. No association between number of ApoE4 alleles and age was found, suggesting the absence of association of ApoE genotype with mortality in this population.

Geographical stratification by socio-economic status: methodology from a household survey with elderly people in S. Paulo, Brazil

Considering that in most developing countries there are still no comprehensive lists of addresses for a given geographical area, there has always been a problem in drawing samples from the community, ensuring randomisation in the selection of the subjects. This article discusses the geographical stratification by socio-economic status used to draw a multistage random sample from a community-based elderly population living in a city like S. Paulo - Brazil. Particular attention is given to the fact that the proportion of elderly people in the total population of a certain area appeared to be a good discriminatory variable for such stratification. The validity of the stratification method is analysed in the light of the socio-economic results obtained in the survey.