Efeitos da angiotensina-I e isquemia na recuperação funcional em corações isolados

FUNDAMENTO: A ressuscitação de parada cardíaca pode apresentar disfunção miocárdica determinada pelo tempo da isquemia, e a inibição da enzima conversora de angiotensina (ECA) pode reduzir a disfunção cardíaca durante a reperfusão. OBJETIVO: Investigar os efeitos da angiotensina-I e diferentes períodos de isquemia na recuperação funcional em corações de ratos isolados. MÉTODOS: Os corações isolados de ratos Wistar (n = 45; 250-300 g) foram submetidos a diferentes períodos de isquemia global (20, 25 ou 30 min) e reperfundidos (30 min) com o tampão Krebs-Henseleit, ou com a adição de 400 nmol/L de angiotensina-I, ou com 400 nmol/L de angiotensina-I + 100 µmol/L de captopril durante o período de reperfusão. RESULTADOS: A derivada positiva máxima de pressão (+dP/dt max) e o produto frequência-pressão foram reduzidos nos corações expostos à isquemia de 25 min (~ 73%) e à isquemia de 30 min (~ 80%) vs. isquemia de 20 min. A pressão diastólica final do ventrículo esquerdo (PDFVE) e a pressão de perfusão (PP) foram aumentadas nos corações expostos à isquemia de 25 min (5,5 e 1,08 vezes, respectivamente) e à isquemia de 30 min (6 e 1,10 vezes, respectivamente) vs. isquemia de 20 min. A angiotensina-I ocasionou uma diminuição no +dP/dt max e no produto frequência-pressão (~ 85-94%) em todos os períodos de isquemia e um aumento na PDFVE e na PP (6,9 e 1,25 vezes, respectivamente) apenas na isquemia de 20 min. O captopril foi capaz de reverter parcial ou completamente os efeitos da angiotensina-I na recuperação funcional nas isquemias de 20 e 25 min CONCLUSÃO: Os dados sugerem que a angiotensina-II participa direta ou indiretamente no dano pós-isquêmico e que a capacidade de um inibidor da ECA atenuar esse dano depende do tempo de isquemia.

Study of the cardiac left atrioventricular valvar complex in water buffaloes (Bubalus bubalis) of the Jafarabadi breed

Atrioventricular valve complex of 30 Jafarabadi water buffaloes, adult males were studied in this research with no heart diseases. The animals were obtained from a slaughterhouse in Brazilian State of Parana. The hearts were opened at the third portion affording access to the valve complex. The complexes had its area, number and type of tendinous cords submitted to analysis. The results showed that the complex is composed by two cusps and four accessory cusps, two or three papillary muscles in which 10-25 tendinous cords fix on the cusps that face the ventricle wall. The total area of the complex was on average 38.56cm², with a minimum of 24.96cm² and a maximum of 55.54cm². Statistically, no relation between the number of cords and the cusps' area where they are inserted or with the number of papillary muscle where they originated from was observed.

What are the similarities between stress, sudden cardiac death in Gallus gallus and sudden unexpected death in people with epilepsy

Individuals with epilepsy are at higher risk of sudden unexpected death in epilepsy (SUDEP), responsible for 7.5% to 17% of all deaths in epilepsy. Many factors are current associated with SUDEP and possible effect of stress and cardiac arrhythmia are still not clear. Sudden death syndrome (SDS) in chickens is a disease characterized by an acute death of well-nourished and seeming healthy Gallus gallus after abrupt and brief flapping of their wings, similar to an epileptic seizure, with an incidence estimated as 0.5 to 5% in broiler chickens. A variety of nutritional and environmental factors have been included: but the exactly etiology of SDS is unknown. Studies had suggested that the hearts of broiler chickens are considerably more susceptible to arrhythmias and stress may induce ventricular arrhythmia and thus, sudden cardiac death. In this way, SDS in Gallus gallus could be an interesting model to study SUDEP.

Flow cytometry as a tool in the evaluation of blood leukocyte function in Chelonia mydas (Linnaeus, 1758) (Testudines, Cheloniidae)

Chelonia mydas is a sea turtle that feeds and nests on the Brazilian coast and a disease called fibropapillomatosis is a threat to this species. Because of this, it is extremely necessary to determine a methodology that would enable the analysis of blood leukocyte function in these sea turtles. In order to achieve this aim, blood samples were collected from C. mydas with or without fibropapillomas captured on the São Paulo north coast. Blood samples were placed in tubes containing sodium heparin and were transported under refrigeration to the laboratory in sterile RPMI 1640 cell culture medium. Leukocytes were separated by density gradient using Ficoll-PaqueTM Plus, Amershan Biociences®. The following stimuli were applied in the assessment of leukocyte function: Phorbol Miristate-Acetate (PMA) for oxidative burst activity evaluation and Zymosan A (Saccharomyces cerevisiae) Bio Particles®, Alexa Fluor® 594 conjugate for phagocytosis evaluation. Three cell populations were identified: heterophils, monocytes and lymphocytes. Monocytes were the cells responsible for phagocytosis and oxidative burst.

Eccentric Hip Muscle Function in Females With and Without Patellofemoral Pain Syndrome

Context: Patellofemoral pain syndrome (PFPS) is a common knee condition in athletes. Recently, researchers have indicated that factors proximal to the knee, including hip muscle weakness and motor control impairment, contribute to the development of PFPS. However, no investigators have evaluated eccentric hip muscle function in people with PFPS. Objective: To compare the eccentric hip muscle function between females with PFPS and a female control group. Design: Cross-sectional study. Setting: Musculoskeletal laboratory. Patients or Other Participants: Two groups of females were studied: a group with PFPS (n = 10) and a group with no history of lower extremity injury or surgery (n = 10). Intervention(s): Eccentric torque of the hip musculature was evaluated on an isokinetic dynamometer. Main Outcome Measure(s): Eccentric hip abduction, adduction, and external and internal rotation peak torque were measured and expressed as a percentage of body mass (Nm/kg x 100). We also evaluated eccentric hip adduction to abduction and internal to external rotation torque ratios. The peak torque value of 5 maximal eccentric contractions was used for calculation. Two-tailed, independent-samples t tests were used to compare torque results between groups. Results: Participants with PFPS exhibited much lower eccentric hip abduction (t(18) = -2.917, P = .008) and adduction (t(18) = -2.764, P =.009) peak torque values than did their healthy counterparts. No differences in eccentric hip external (t(18) = 0.45, P = .96) or internal (t(18) = -0.742, P =.47) rotation peak torque values were detected between the groups. The eccentric hip adduction to abduction torque ratio was much higher in the PFPS group than in the control group (t(18) = 2.113, P = .04), but we found no difference in the eccentric hip internal to external rotation torque ratios between the 2 groups (t(18) = -0.932, P = .36). Conclusions: Participants with PFPS demonstrated lower eccentric hip abduction and adduction peak torque and higher eccentric adduction to abduction torque ratios when compared with control participants. Thus, clinicians should consider eccentric hip abduction strengthening exercises when developing rehabilitation programs for females with PFPS.

The four hexamerin genes in the honey bee: structure, molecular evolution and function deduced from expression patterns in queens, workers and drones

Background: Hexamerins are hemocyanin-derived proteins that have lost the ability to bind copper ions and transport oxygen; instead, they became storage proteins. The current study aimed to broaden our knowledge on the hexamerin genes found in the honey bee genome by exploring their structural characteristics, expression profiles, evolution, and functions in the life cycle of workers, drones and queens. Results: The hexamerin genes of the honey bee (hex 70a, hex 70b, hex 70c and hex 110) diverge considerably in structure, so that the overall amino acid identity shared among their deduced protein subunits varies from 30 to 42%. Bioinformatics search for motifs in the respective upstream control regions (UCRs) revealed six overrepresented motifs including a potential binding site for Ultraspiracle (Usp), a target of juvenile hormone (JH). The expression of these genes was induced by topical application of JH on worker larvae. The four genes are highly transcribed by the larval fat body, although with significant differences in transcript levels, but only hex 110 and hex 70a are re-induced in the adult fat body in a caste-and sex-specific fashion, workers showing the highest expression. Transcripts for hex 110, hex 70a and hex70b were detected in developing ovaries and testes, and hex 110 was highly transcribed in the ovaries of egg-laying queens. A phylogenetic analysis revealed that HEX 110 is located at the most basal position among the holometabola hexamerins, and like HEX 70a and HEX 70c, it shares potential orthology relationship with hexamerins from other hymenopteran species. Conclusions: Striking differences were found in the structure and developmental expression of the four hexamerin genes in the honey bee. The presence of a potential binding site for Usp in the respective 5' UCRs, and the results of experiments on JH level manipulation in vivo support the hypothesis of regulation by JH. Transcript levels and patterns in the fat body and gonads suggest that, in addition to their primary role in supplying amino acids for metamorphosis, hexamerins serve as storage proteins for gonad development, egg production, and to support foraging activity. A phylogenetic analysis including the four deduced hexamerins and related proteins revealed a complex pattern of evolution, with independent radiation in insect orders.

ECG scar quantification correlates with cardiac magnetic resonance scar size and prognostic factors in Chagas' disease

Objective To test the hypothesis that 12-lead ECG QRS scoring quantifies myocardial scar and correlates with disease severity in Chagas' heart disease. Design Patients underwent 12-lead ECG for QRS scoring and cardiac magnetic resonance with late gadolinium enhancement (CMR-LGE) to assess myocardial scar. Setting University of Sao Paulo Medical School, Sao Paulo, Brazil. Patients 44 Seropositive patients with Chagas' disease without a history of myocardial infarction and at low risk for coronary artery disease. Main outcome measures Correlation between QRS score, CMR-LGE scar size and left ventricular ejection fraction. Relation between QRS score, heart failure (HF) class and history of ventricular tachycardia (VT). Results QRS score correlated directly with CMR-LGE scar size (R=0.69, p<0.0001) and inversely with left ventricular ejection fraction (R=-0.54, p=0.0002), which remained significant in the subgroup with conduction defects. Patients with class II or III HF had significantly higher QRS scores than those with class I HF (5.1 +/- 3.4 vs 2.1 +/- 3.1 QRS points (p=0.002)) and patients with a history of VT had significantly higher QRS scores than those without a history of VT (5.3 +/- 3.2% vs 2.6 +/- 3.4 QRS points (p=0.02)). A QRS score >= 2 points had particularly good sensitivity and specificity (95% and 83%, respectively) for prediction of large CMR-LGE, and a QRS score >= 7 points had particularly high specificity (92% and 89%, respectively) for predicting significant left ventricular dysfunction and history of VT. Conclusions The wide availability of 12-lead ECG makes it an attractive screening tool and may enhance clinical risk stratification of patients at risk for more severe, symptomatic Chagas' heart disease.

Aerobic capacity and skeletal muscle function in children with asthma

Background Peripheral muscle strength and endurance are decreased in patients with chronic pulmonary diseases and seem to contribute to patients' exercise intolerance. However, the authors are not aware of any studies evaluating peripheral muscle function in children with asthma. It seems to be implied that children with asthma have lower aerobic fitness, but there are limited studies comparing the aerobic capacity of children with and without asthma. The present study aimed to evaluate muscle strength and endurance in children with persistent asthma and their association with aerobic capacity and inhaled corticosteroid consumption. Methods Forty children with mild persistent asthma (MPA) or severe persistent asthma (SPA) (N=20 each) and 20 children without asthma (control group) were evaluated. Upper (pectoralis and latissimus dorsi) and lower (quadriceps) muscle strength and endurance were assessed, and cardiopulmonary exercise testing was performed. Inhaled corticosteroid consumption during the last 6 and 24 months was also quantified. Results Children with SPA presented a reduction in peak oxygen consumption (VO(2)) (28.2 +/- 8.1 vs 34.7 +/- 6.9 ml/kg/min; p<0.01) and quadriceps endurance (43.1 +/- 6.7 vs 80.9 +/- 11.9 repetitions; p<0.05) compared with the control group, but not the MPA group (31.5 +/- 6.1 ml/kg/min and 56.7 +/- 47.7 repetitions respectively; p>0.05). Maximal upper and lower muscle strength was preserved in children with both mild and severe asthma (p>0.05). Finally, the authors observed that lower muscle endurance weakness was not associated with reductions in either peak VO(2) (r=0.22, p>0.05) or corticosteroid consumption (r=-0.31, p>0.05) in children with asthma. Conclusion The findings suggest that cardiopulmonary exercise and lower limb muscle endurance should be a priority during physical training programs for children with severe asthma.

High Prevalence of Side Effects After Recombinant Human Thyrotropin-Stimulated Radioiodine Treatment with 30 mCi in Patients with Multinodular Goiter and Subclinical/Clinical Hyperthyroidism

Background: Treatment of multinodular goiters (MNGs) is highly controversial. Radioiodine (RAI) therapy is a nonsurgical alternative for the elderly who decline surgery. Recently, recombinant human thyrotropin (rhTSH) has been used to augment RAI uptake and distribution. In this study, we determined the outcome of 30 mCi RAI preceded by rhTSH (0.1 mg) in euthyroid (EU) and hyperthyroid (subclinical/clinical) patients with large MNGs. Methods: This was a prospective cohort study. Forty-two patients (age, 43-80 years) with MNGs were treated with 30 mCi RAI after stimulation with 0.1 mg of rhTSH. Patients were divided into three groups, according to thyroid function: EU (n = 18), subclinically hyperthyroid (SC-H, n = 18), and clinically hyperthyroid (C-H, n = 6). All patients underwent a 90-day low-iodine diet before treatment, and those with clinical hyperthyroidism received methimazole 10 mg daily for 30 days. Serum TSH, free thyroxine (FT4), total triiodothyronine (TT3), and thyroglobulin were measured at baseline and at 24, 48, 72, 168 hours, and 1, 3, 6, 9, 12, 18, 24, and 36 months after therapy. Thyroid volume was assessed by computed tomography at baseline and every 6 months. Results: Patients had high iodine urinary excretion (308 +/- 108 mu g I/L) at baseline. TSH levels at baseline were within the normal range (1.5 +/- 0.7 mu U/mL) in the EU group and suppressed (< 0.3 mu U/mL) in the SC-H and C-H groups. After rhTSH, serum TSH peaked at 24 hours reaching 12.4 +/- 5.85 mu U/mL. After RAI administration, patients in both hyperthyroid groups had a higher increase in FT4 and TT3 compared with those in the EU group (p < 0.001). Thyroglobulin levels increased equally in all three groups until day 7. Thyroid volume decreased significantly in all patients. Side effects were more common in the SC-H and C-H groups (31.4% and 60.4%, respectively) compared with EU patients (17.8%). Permanent hypothyroidism was more prevalent in the EU group (50%) compared with the SC-H (11%) and C-H (16.6%) groups. Conclusions: Patients with MNG may have subclinical and clinical nonautoimmune iodine-induced hyperthyroidism. Despite a low-iodine diet and therapy with methimazole, hyperthyroid patients have a significantly higher increase in FT4 and TT3 levels after RAI ablation. This can lead to important side effects related mostly to the cardiac system. We strongly advise that patients with SC-H and C-H be adequately treated with methimazole and low-iodine diet aiming to normalize their hyperthyroid condition before rhTSH-stimulated treatment with RAI.

The Borg Scale as an Important Tool of Self-Monitoring and Self-Regulation of Exercise Prescription in Heart Failure Patients During Hydrotherapy - A Randomized Blinded Controlled Trial

Background: The Borg Scale may be a useful tool for heart failure patients to self-monitor and self-regulate exercise on land or in water (hydrotherapy) by maintaining the heart rate (HR) between the anaerobic threshold and respiratory compensation point. Methods and Results: Patients performed a cardiopulmonary exercise test to determine their anaerobic threshold/respiratory compensation points. The percentage of the mean HR during the exercise session in relation to the anaerobic threshold HR (%EHR-AT), in relation to the respiratory compensation point (%EHR-RCP), in relation to the peak HR by the exercise test (%EHR-Peak) and in relation to the maximum predicted HR (%EHR-Predicted) was calculated. Next, patients were randomized into the land or water exercise group. One blinded investigator instructed the patients in each group to exercise at a level between ""relatively easy and slightly tiring"". The mean HR throughout the 30-min exercise session was recorded. The %EHR-AT and %EHR-Predicted did not differ between the land and water exercisegroups, but they differed in the %EHR-RCP (95 +/- 7 to 86 +/- 7. P<0.001) and in the %EHR-Peak (85 +/- 8 to 78 +/- 9, P=0.007). Conclusions: Exercise guided by the Borg scale maintains the patient's HR between the anaerobic threshold and respiratory compensation point (ie, in the exercise training zone). (Circ J 2009; 73: 1871-1876)

Five-year follow-up of angiographic disease progression after medicine, angioplasty, or surgery

Background: Progression of atherosclerosis in coronary artery disease is observed through consecutive angiograms. Prognosis of this progression in patients randomized to different treatments has not been established. This study compared progression of coronary artery disease in native coronary arteries in patients undergoing surgery, angioplasty, or medical treatment. Methods: Patients (611) with stable multivessel coronary artery disease and preserved ventricular function were randomly assigned to CABG, PCI, or medical treatment alone (MT). After 5-year follow-up, 392 patients (64%) underwent new angiography. Progression was considered a new stenosis of >= 50% in an arterial segment previously considered normal or an increased grade of previous stenosis > 20% in nontreated vessels. Results: Of the 392 patients, 136 underwent CABG, 146 PCI, and 110 MT. Baseline characteristics were similar among treatment groups, except for more smokers and statin users in the MT group, more hypertensives and lower LDL-cholesterol levels in the CABG group, and more angina in the PCI group at study entry. Analysis showed greater progression in at least one native vessel in PCI patients (84%) compared with CABG (57%) and MT (74%) patients (p < 0.001). LAD coronary territory had higher progression compared with LCX and RCA (P < 0.001). PCI treatment, hypertension, male sex, and previous MI were independent risk factors for progression. No statistical difference existed between coronary events and the development of progression. Conclusion: The angioplasty treatment conferred greater progression in native coronary arteries, especially in the left anterior descending territories and treated vessels. The progression was independently associated with hypertension, male sex, and previous myocardial infarction.

Hypotheses, rationale, design, and methods for prognostic evaluation in type 2 diabetic patients with angiographically normal coronary arteries. The MASS IV-DM Trial

Background: The MASS IV-DM Trial is a large project from a single institution, the Heart Institute (InCor), University of Sao Paulo Medical School, Brazil to study ventricular function and coronary arteries in patients with type 2 diabetes mellitus. Methods/Design: The study will enroll 600 patients with type 2 diabetes who have angiographically normal ventricular function and coronary arteries. The goal of the MASS IV-DM Trial is to achieve a long-term evaluation of the development of coronary atherosclerosis by using angiograms and coronary-artery calcium scan by electron-beam computed tomography at baseline and after 5 years of follow-up. In addition, the incidence of major cardiovascular events, the dysfunction of various organs involved in this disease, particularly microalbuminuria and renal function, will be analyzed through clinical evaluation. In addition, an effort will be made to investigate in depth the presence of major cardiovascular risk factors, especially the biochemical profile, metabolic syndrome inflammatory activity, oxidative stress, endothelial function, prothrombotic factors, and profibrinolytic and platelet activity. An evaluation will be made of the polymorphism as a determinant of disease and its possible role in the genesis of micro- and macrovascular damage. Discussion: The MASS IV-DM trial is designed to include diabetic patients with clinically suspected myocardial ischemia in whom conventional angiography shows angiographically normal coronary arteries. The result of extensive investigation including angiographic follow-up by several methods, vascular reactivity, pro-thrombotic mechanisms, genetic and biochemical studies may facilitate the understanding of so-called micro- and macrovascular disease of DM.

Cardiac arrhythmia emergency room visits and environmental air pollution in Sao Paulo, Brazil

Objectives: Air-pollution exposure has been associated with increased cardiovascular hospital admissions and mortality in time-series studies. We evaluated the relation between air pollutants and emergency room (ER) visits because of cardiac arrhythmia in a cardiology hospital. Methods: In a time-series study, we evaluated the association between the emergency room visits as a result of cardiac arrhythmia and daily variations in SO2, CO, NO2, O-3 and PM10, from January 1998 to August 1999. The cases of arrhythmia were modelled using generalised linear Poisson regression models, controlling for seasonality (short-term and long-term trend), and weather. Results: Interquartile range increases in CO (1.5 ppm), NO2 (49,5 mu g/m(3)) and PM10 (22.2 mu g/m(3)) on the concurrent day were associated with increases of 12.3% (95% CI: 7.6% to 17.2%), 10.4% (95% CI: 5.2% to 15.9%) and 6.7% (95% CI: 1.2% to 12.4%) in arrhythmia ER visits, respectively. PM10, CO and NO2 effects were dose-dependent and gaseous pollutants had thresholds. Only CO effect resisted estimates in models with more than one pollutant. Conclusions: Our results showed that air pollutant effects on arrhythmia are predominantly acute starting at concentrations below air quality standards, and the association with CO and NO2 suggests a relevant role for pollution caused by cars.

Myocardial ultrasonic tissue characterization in patients with thyroid dysfunction

Background: Structural myocardial abnormalities have been extensively documented in hypothyroidism. Experimental studies in animal models have also shown involvement of thyroid hormones in gene expression of myocardial collagen. This study was planned to investigate the ability of ultrasonic tissue characterization, as evaluated by integrated backscatter (IBS), to early identify myocardial involvement in thyroid dysfunction. Patients and Methods: We studied 15 patients with hyperthyroidism (HYPER), 8 patients with hypothyroidism (HYPO), 14 patients with subclinical hypothyroidism (SCH) and 19 normal (N) subjects, who had normal LV systolic function. After treatment, 10 HYPER, 6 HYPO, and 8 SCH patients were reevaluated. IBS images were obtained and analyzed in parasternal short axis (papillary muscle level) view, at left ventricular (LV) posterior wall. The following IBS variables were analyzed: 1) the corrected coefficient (CC) of IBS, obtained by dividing IBS intensity by IBS intensity measured in a rubber phantom, using the same equipment adjustments, at the same depth; 2) cardiac cyclic variation (CV) of IBS - peak-to-peak difference between maximal and minimal values of IBS during cardiac cycle; 3) cardiac cyclic variation index (CVI) of IBS - percentual relationship between the cyclic variation (CV) and the mean value of IBS intensity. Results: CC of IBS was significantly larger (p < 0.05) in HYPER (1.57 +/- 0.6) and HYPO (1.53 +/- 0.3) as compared to SCH (1.32 +/- 0.3) or N (1.15 +/- 0.27). The CV (dB) (HYPO: 7.5 +/- 2.4; SCH: 8.2 +/- 3.1; HYPER: 8.2 +/- 2.0) and the CVI (HYPO: 35.6 +/- 19.7%; SCH: 34.7 +/- 17.5%; HYPER: 37.8 +/- 11.6%) were not significantly different in patients with thyroid dysfunction as compared to N (7.0 +/- 2.0 and 44.5 +/- 15.1%). Conclusions: CC of IBS was able to differentiate cardiac involvement in patients with overt HYPO and HYPER who had normal LV systolic function. These early myocardial structural abnormalities were partially reversed by drug therapy in HYPER group. On the other hand, although mean IBS intensity tended to be slightly larger in patients with SCH as compared to N, this difference was not statistical significant.

Endothelial Nitric Oxide Synthase Haplotypes Associated with Hypertension Do Not Predispose to Cardiac Hypertrophy

Left ventricular hypertrophy (LVH) is a complication that may result from chronic hypertension. While nitric oxide (NO) deficiency has been associated with LVH, inconsistent results have been reported with regards to the association of endothelial NO synthase (eNOS) polymorphisms and LVH in hypertensive patients. This study aims to assess whether eNOS haplotypes are associated with LVH in hypertensive patients. This study included 101 healthy controls and 173 hypertensive patients submitted to echocardiography examination. Genotypes for three eNOS polymorphisms were determined: a single-nucleotide polymorphism in the promoter region (T-786C) and in exon 7 (Glu298Asp), and variable number of tandem repeats in intron 4. We found no significant association between eNOS genotypes and hypertension or with LVH (all p>0.05). However, while we found two eNOS haplotypes associated with variable risk of hypertension (all p<0.05), we found no significant associations between eNOS haplotypes and LVH (all p>0.05), even after adjustment in multiple linear regression analysis. These findings suggest that eNOS haplotypes that have been associated with variable susceptibility to hypertension were not associated with LVH in hypertensive patients. Further studies are necessary to examine whether other genes downstream may interact with eNOS polymorphisms and predispose to LVH in hypertensive patients.