Photosynthetic parameters and growth in seedlings of Bertholletia excelsa and Carapa guianensis in response to pre-acclimation to full sunlight and mild water stress

Light and water are important factors that may limit the growth and development of higher plants. The aim of this study was to evaluate photosynthetic parameters and growth in seedlings of Bertholletia excelsa and Carapa guianensis in response to pre-acclimation to full sunlight and mild water stress. I used six independent pre-acclimation treatments (0, 90 (11h15-12h45), 180 (10h30-13h30), 360 (09h00-15h00), 540 (07h30-16h30) and 720 min (06h00-18h00)) varying the time of exposure to full sunlight (PFS) during 30 days, followed by whole-day outdoor exposure for 120 days. Before PFS, the plants were kept in a greenhouse at low light levels (0.8 mol m-2 day-1). The PFS of 0 min corresponded to plants constantly kept under greenhouse conditions. From the beginning to the end of the experiment, each PFS treatment was submitted to two water regimes: moderate water stress (MWS, pre-dawn leaf water potential (ΨL) of -500 to -700 kPa) and without water stress (WWS, ΨL of -300 kPa, soil kept at field capacity). Plants under MWS received only a fraction of the amount of water applied to the well-watered ones. At the end of the 120-day-period under outdoor conditions, I evaluated light saturated photosynthesis (Amax), stomatal conductance (g s), transpiration (E) and plant growth. Both Amax and g s were higher for all plants under the PFS treatment. Stem diameter growth rate and Amax were higher for C. guianensis subjected to MWS than in well-watered plants. The contrary was true for B. excelsa. The growth of seedlings was enhanced by exposure to full sunlight for 180 minutes in both species. However, plants of B. excelsa were sensitive to moderate water stress. The higher photosynthetic rates and faster growth of C. guianensis under full sun and moderate water stress make this species a promissory candidate to be tested in reforestation programs.

Natural gaps associated with oxidative stress in Willisornis poecilinotus (Aves: Thamnophilidae) in a tropical forest

Natural disturbances in tropical forests modify the availability and quality of resources and alter the patterns of bird distribution. These environmental changes increase the metabolic rate and disrupt the redox balance promoting oxidative stress. This study aimed to compare the abundance of Willisornis poecilinotus between gaps and the understory of a forest with undisturbed canopy at Caxiuanã National Forest. The abundance was correlated with vegetation heights. The oxidative stress and the stress promoting factors were determined in both sites of sampling. We captured 81 specimens of W. poecilinotus. The number of captures was high in gaps. The specimens sampled at gaps showed high levels of oxidative stress. The biomarkers of oxidative stress were significantly correlated in gaps. The variability of oxidative stress and oxidative damage were explained only by site of sampling. These results suggest that gaps are stressors sites to W. poecilinotus, which probably can be due to an increase of metabolic rate to deal with new flight strategies of foraging and avoid predation

Posttraumatic stress disorder: prevalences, comorbidities and quality of life in a community sample of young adults

Objectives To verify the prevalence of current posttraumatic stress disorder (PTSD) in young adults, the occurrence of comorbidities and its association with quality of life. Methods This is a cross-sectional population-based study. The targeted population consisted on individuals aged 18 to 24 years old, who lived in the urban area of Pelotas-RS, Brazil. Cluster sampling was applied. PTSD and its comorbidities were assessed using the Mini International Neuropsychiatric Interview (MINI 5.0), whereas quality of life was evaluated with the eight domains of the Medical Outcomes Survey Short-form General Health Survey (SF-36). Results A total of 1,762 young adults were selected. The prevalence of PTSD was 2.1% and current episode of depression was the most prevalent comorbidity (71.9%). The individuals with PTSD had lower scores in all domains of quality of life. Conclusion These findings indicate that PTSD is associated with other psychopathologies, especially depression, and it has a substantial impact over quality of life in a sample of young adults.

Exercise stress testing in healthy subjects during cholinergic stimulation after a single dose of pyridostigmine

OBJETIVE: The evaluation, by exercise stress testing, of the cardiorespiratory effects of pyridostigmine (PYR), a reversible acetylcholinesterase inhibitor. METHODS: A double-blind, randomized, cross-over, placebo-controlled comparison of hemodynamic and ventilation variables of 10 healthy subjects who underwent three exercise stress tests (the first for adaptation and determination of tolerance to exercise, the other two after administration of placebo or 45mg of PYR). RESULTS: Heart rate at rest was: 68±3 vs 68±3bpm before and after placebo, respectively (P=0.38); 70±2 vs 59±2bpm, before and after pyridostigmine, respectively (P<0.01). During exercise, relative to placebo: a significantly lower heart rate after PYR at, respectively, 20% (P=0.02), 40% (P=0.03), 80% (P=0.05) and 100% (P=0.02) of peak effort was observed. No significant differences were observed in arterial blood pressure, oxygen consumption at submaximal and maximal effort, exercise duration, respiratory ratio, CO2 production, ventilation threshold, minute ventilation, and oxygen pulse. CONCLUSION: Pyridostigmine, at a dose of 45mg, decreases heart rate at rest and during exercise, with minimal side effects and without interfering with exercise tolerance and ventilation variables.

Stress During ACLS Courses: Is it Important for Learning Skills?

OBJECTIVE: To determine the influence of stress on teaching medical emergencies in an Advanced Cardiac Life Support (ACLS) course and to verify this influence on learning, and the efficiency of emergency care training. METHODS: Seventeen physicians signed up for an ACLS course. Their pulses were taken and blood pressure (BP) verified on the first day, before the beginning of the course, and on the second day, during the theoretical and practical test (TPT). Variations in pulse rates and BP were compared with students' test grades. Then, students answered a questionnaire of variables (QV) about the amount of sleep they had during the course, the quantity of study material and the time spent studying for the course, and a stress scale graphic. RESULTS: Seven students had a pulse variation less than 10% between the 2 periods and 10 had a 10% or more variation. Grades on TPT were, respectively, 91.4±2.4 and 87.3±5.2 (p<0.05). Six students had a BP variation less than 20 mmHg, and in 11 it varied more than 21 mmHg. Grades on the TPT were 92.3±3.3 and 86.2± 8.1, respectively (p<0.05). The QV dates did not significantly influence grades. CONCLUSION: Stress, as an isolated variable, had a negative influence on the learning process and on the efficiency of emergency training in this situation.

Physical Stress Echocardiography: Prediction of Mortality and Cardiac Events in Patients with Exercise Test showing Ischemia

Background: Studies have demonstrated the diagnostic accuracy and prognostic value of physical stress echocardiography in coronary artery disease. However, the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia is limited. Objective: To evaluate the effectiveness of physical stress echocardiography in the prediction of mortality and major cardiac events in patients with exercise test positive for myocardial ischemia. Methods: This is a retrospective cohort in which 866 consecutive patients with exercise test positive for myocardial ischemia, and who underwent physical stress echocardiography were studied. Patients were divided into two groups: with physical stress echocardiography negative (G1) or positive (G2) for myocardial ischemia. The endpoints analyzed were all-cause mortality and major cardiac events, defined as cardiac death and non-fatal acute myocardial infarction. Results: G2 comprised 205 patients (23.7%). During the mean 85.6 ± 15.0-month follow-up, there were 26 deaths, of which six were cardiac deaths, and 25 non-fatal myocardial infarction cases. The independent predictors of mortality were: age, diabetes mellitus, and positive physical stress echocardiography (hazard ratio: 2.69; 95% confidence interval: 1.20 - 6.01; p = 0.016). The independent predictors of major cardiac events were: age, previous coronary artery disease, positive physical stress echocardiography (hazard ratio: 2.75; 95% confidence interval: 1.15 - 6.53; p = 0.022) and absence of a 10% increase in ejection fraction. All-cause mortality and the incidence of major cardiac events were significantly higher in G2 (p < 0. 001 and p = 0.001, respectively). Conclusion: Physical stress echocardiography provides additional prognostic information in patients with exercise test positive for myocardial ischemia.

Chronic Stress Improves NO- and Ca2+ Flux-Dependent Vascular Function: A Pharmacological Study

Background: Stress is associated with cardiovascular diseases. Objective: This study aimed at assessing whether chronic stress induces vascular alterations, and whether these modulations are nitric oxide (NO) and Ca2+ dependent. Methods: Wistar rats, 30 days of age, were separated into 2 groups: control (C) and Stress (St). Chronic stress consisted of immobilization for 1 hour/day, 5 days/week, 15 weeks. Systolic blood pressure was assessed. Vascular studies on aortic rings were performed. Concentration-effect curves were built for noradrenaline, in the presence of L-NAME or prazosin, acetylcholine, sodium nitroprusside and KCl. In addition, Ca2+ flux was also evaluated. Results: Chronic stress induced hypertension, decreased the vascular response to KCl and to noradrenaline, and increased the vascular response to acetylcholine. L-NAME blunted the difference observed in noradrenaline curves. Furthermore, contractile response to Ca2+ was decreased in the aorta of stressed rats. Conclusion: Our data suggest that the vascular response to chronic stress is an adaptation to its deleterious effects, such as hypertension. In addition, this adaptation is NO- and Ca2+-dependent. These data help to clarify the contribution of stress to cardiovascular abnormalities. However, further studies are necessary to better elucidate the mechanisms involved in the cardiovascular dysfunction associated with stressors. (Arq Bras Cardiol. 2014; [online].ahead print, PP.0-0)

Assessment of Myocardial Ischemia in Obese Individuals Undergoing Physical Stress Echocardiography (PSE)

Background: Physical stress echocardiography is an established methodology for diagnosis and risk stratification of coronary artery disease in patients with physical capacity. In obese (body mass index ≥ 30 kg/m2) the usefulness of pharmacological stress echocardiography has been demonstrated; however, has not been reported the use of physical stress echocardiography in this growing population group. Objective: To assess the frequency of myocardial ischemia in obese and non-obese patients undergoing physical stress echocardiography and compare their clinical and echocardiographic differences. Methods: 4,050 patients who underwent treadmill physical stress echocardiography were studied according to the Bruce protocol, divided into two groups: obese (n = 945; 23.3%) and non-obese (n = 3,105; 76.6%). Results: There was no difference regarding gender. Obese patients were younger (55.4 ± 10.9 vs. 57.56 ± 11.67) and had a higher frequency of hypertension (75.2% vs. 57, 2%; p < 0.0001), diabetis mellitus (15.2% vs. 10.9%; p < 0.0001), dyslipidemia (59.5% vs 51.9%; p < 0.0001), family history of coronary artery disease (59.3% vs. 55.1%; p = 0.023) and physical inactivity (71.4% vs. 52.9%, p < 0.0001). The obese had greater aortic dimensions (3.27 vs. 3.14 cm; p < 0.0001), left atrium (3.97 vs. 3.72 cm; p < 0.0001) and the relative thickness of the ventricule (33.7 vs. 32.8 cm; p < 0.0001). Regarding the presence of myocardial ischemia, there was no difference between groups (19% vs. 17.9%; p = 0.41). In adjusted logistic regression, the presence of myocardial ischemia remained independently associated with age, female gender, diabetes and hypertension. Conclusion: Obesity did not behave as a predictor of the presence of ischemia and the physical stress echocardiography. The application of this assessment tool in large scale sample demonstrates the feasibility of the methodology, also in obese.

Dipyridamole stress myocardial perfusion by computed tomography in patients with left bundle branch block

Abstract Background: Functional tests have limited accuracy for identifying myocardial ischemia in patients with left bundle branch block (LBBB). Objective: To assess the diagnostic accuracy of dipyridamole-stress myocardial computed tomography perfusion (CTP) by 320-detector CT in patients with LBBB using invasive quantitative coronary angiography (QCA) (stenosis ≥ 70%) as reference; to investigate the advantage of adding CTP to coronary computed tomography angiography (CTA) and compare the results with those of single photon emission computed tomography (SPECT) myocardial perfusion scintigraphy. Methods: Thirty patients with LBBB who had undergone SPECT for the investigation of coronary artery disease were referred for stress tomography. Independent examiners performed per-patient and per-coronary territory assessments. All patients gave written informed consent to participate in the study that was approved by the institution’s ethics committee. Results: The patients’ mean age was 62 ± 10 years. The mean dose of radiation for the tomography protocol was 9.3 ± 4.6 mSv. With regard to CTP, the per-patient values for sensitivity, specificity, positive and negative predictive values, and accuracy were 86%, 81%, 80%, 87%, and 83%, respectively (p = 0.001). The per-territory values were 63%, 86%, 65%, 84%, and 79%, respectively (p < 0.001). In both analyses, the addition of CTP to CTA achieved higher diagnostic accuracy for detecting myocardial ischemia than SPECT (p < 0.001). Conclusion: The use of the stress tomography protocol is feasible and has good diagnostic accuracy for assessing myocardial ischemia in patients with LBBB.

Peanut (Araohis hypogaea cv. Tatu-53) productivity under nutrient foliar sprays containing growth regulators

Two nutrient foliar sprays, namely Ferti-Foliage (21-21 -21) and Wuxal (9-9-7), were applied to peanut plants under field conditions. Both were applied 23 days after germination of seeds, at the beginning of flowering, and during flowering. Other treatments were application of NPK fertilizer (9-30-16, 250 kg/ha) into the soil and check (no fertilizer). The experiment was carried out on a latosolic B "Terra Roxa" soil, sowing being made on March 6th and harvest on July 10th. Statistical analysis showed no significant differences amongst treatments. However, certain treatments had better yields. For instance, application of Ferti-Foliage showed a tendency to increasing number of pods per plant and number of seeds per pod. Same product when applied at the beginning of flowering had a tendency to increase production of seeds and of forage. Application of NPK (9-30-16) into the soil showed similar results.

Effects of nutrient foliar sprays containing growth regulators on productivity of peanut (Arachis hypogaea L. cv. Tatu-53)

The effects of the application of a macronutrient foliar spray combined with micronutrients and growth regulators (Unifol) on peanut grown in a soil with high fertility were investigated. A control without fertilizer and a soil fertilization (250 kg/ha) with NPK 9-30-16 were also established. Other treatments were as follows: Unifol fertilizer (18-12 16) applied 23 days after germination: Unifol (18-12-6) applied at the beginning of flowering; Unifol (18-12-6) applied during flowering, and Unifol (18-12-6) applied 23 days after germination plus Unifol (7-23-7) at the beginning of flowering. No significant differences were found amongst treatments, but certain treatments showed higher productivity e given Unifol fertilizer (18-12-6) applied 23 days after germination plus Unifol (7-23-7) at the flower anthesis. In this treatment, the number of pods, weight of seeds and production of seeds were higher. Best production of forage occurred in the treatment receiving soil fertilization.

Nutrient deficiencies in apple plants (Pyrus malus L.)

A trial was carried out with one year old 'Ohio Beauty apples (grafted on 'Doucin'), grown on sand cu1ture, receining nutrient solutions lacking the following nutrients at the time: N, P, K, Ca, Mg, S, and B. The main conclusions are as follows: as the adequate and inadequate levels from leaf analysis were, respectively: N -2.22 and 1.53%, P - 0,17 and 0.05%, K - 1.32 and 0.33%; Ca -0.9.4 and 0.52%, Mg - 0.37 and 0.06%; S -0.18 and 0.08%; B -62 and 2k ppm.

Absorption and nutrient concentration in apple (Pyrus mains L.)

In order to obtain the following informations: a) dry matter production and extraction of nutrients by the fruits at different ages; b) dry matter production and extraction of nutrient by the leaves and "trunk + branches" collected at the flowering stage; c) dry matter production and export of nutrients by pruning (leaves and branches) at the begining dormant stage; A trial was conducted on Latossolo Vermelho Escuro Orto group (Orthox) at Buri, São Paulo State, Brazil. The material was collected from 'Ohio Beauty' and 'Brazil' apples grafted on 'Doucin' 1-2; 3-4; 4-5 and 6-7 years old. The main conclusions were as follows: a) differences were observed on dry matter production by two varieties at the different stages of growth; b) differences were also observed between the two varieties on the matter production in the leaves and "trunk + branches" at the flowering stage, as well as by the leaves and branches pruned at the begining of dormant stages; c) differences were observed betwen the two varieties concerning to nutrient concentration (on dry matter basis) on the fruits collected at different stages of growth. Same results were observed on leaves and "trunk + branches" collected at flowering period; d) differences were observed on the exportation of the nutrients referring to growth period of fruit; e) at the flowering and dormant period, differences were observed on the contents of nutrients in the leaves, 'trunk + branches', on the two varieties; f) the nutrient exportation by the fruits obyed the following order: K>N>P>S>Ca>Mg>Fe>B > Cu > Mn > Zn > Mo; g) the nutrient extration by the aerial part the apple trees obyed the following order: N > K > Ca > Mg > P > S > Fe > B > Cu = Mn = Zn.

Dry matter production and nutrient exportation by pruned leaves and branches of apple trees

A trial was conducted on Latossol Vermelho Escuro Orto (Orthox) at Buri, State of São Paulo, Brazil. The material was collected from 'Ohio Beauty¹ and 'Brasil¹ apples trees grafted on 'Doucin'; the trees were 3-4, 4-5 and 6-7 years old. The authors concluded that at the dormant period differen ces were observed on the dry matter production as well on the nutrients exported by the leaves and branches of the two varieties. Branches exported higher amounts of P, Ca, B, Cu and Zn. Larger quantities of N, P and Mn were exported by the 1 eaves.