Study of autonomic modulation by non-linear analysis of heart rate variability in different age groups and analysis of health status, disease and risk of death in dogs

The symbolic analysis of heart rate variability (biomarker of cardiac autonomic homeostasis) is a nonlinear and effective tool for pattern extraction and classification in a series analysis, which implies the transformation of an original time series into symbols, represented by numbers. Autonomic heart rate control is influenced by different factors, and better indicators of heart rate variability are found in healthy young individuals than in older and sicker individuals. The aim of this study was to compare the indicators of heart rate variability among healthy dogs in different age groups and in health status using the nonlinear method of symbolic analysis to evaluate the diagnostic accuracy of this method for the risk of death in dogs. An increase in cardiac sympathetic modulation was observed in puppies and dogs at risk of death, which was evidenced by a marked increase of 0 V% (without variation - associated with sympathetic modulation) and a decrease in patterns of 2 V% (two variations - associated with parasympathetic modulation), while the opposite was observed in young adult dogs with increased parasympathetic modulation. Elderly dogs showed a gradual decrease in parasympathetic activity, which tended to worsen with loss of health. It is concluded that the variables of symbolic analysis may be useful to evaluate autonomic modulation in dogs and assist in the differentiation between health states, advanced disease and death throughout the life cycle and have been shown to be indices with high specificity, sensitivity and diagnostic accuracy to help identify dogs at risk of death.

Effects of cold water immersion and active recovery on post-exercise heart rate variability

The aim of the present study was to investigate the potential benefits of cold water immersion (CWI) and active recovery (AR) on blood lactate concentration ([Lac]) and heart rate variability (HRV) indices following high-intensity exercise. 20 male subjects were recruited. On the first visit, an incremental test was performed to determine maximal oxygen consumption and the associated speed (MAS). The remaining 3 visits for the performance of constant velocity exhaustive tests at MAS and different recovery methods (6 min) were separated by 7-day intervals [randomized: CWI, AR or passive recovery (PR)]. The CWI and AR lowered [Lac] (p<0.05) at 11, 13 and 15 min after exercise cessation in comparison to PR. There was a 'time' and 'recovery mode' interaction for 2 HRV indices: standard deviation of normal R-R intervals (SDNN) (partial eta squared=0.114) and natural log of low-frequency power density (lnLF) (partial eta squared=0.090). CWI presented significantly higher SDNN compared to PR at 15 min of recovery (p<0.05). In addition, greater SDNN values were found in CWI vs. AR during the application of recovery interventions, and at 30 and 75 min post-exercise (p<0.05 for all differences). The lnLF during the recovery interventions and at 75 min post-exercise was greater using CWI compared with AR (p<0.05). For square root of the mean of the sum of the squares of differences between adjacent R-R intervals (RMSSD) and natural log of high-frequency power density (lnHF), a moderate effect size was found between CWI and PR during the recovery interventions and at 15 min post-exercise. Our findings show that AR and CWI offer benefits regarding the removal of [Lac] following high-intensity exercise. While limited, CWI results in some improvement in post-exercise cardiac autonomic regulation compared to AR and PR. Further, AR is not recommended if the aim is to accelerate the parasympathetic reactivation.

Edible mushroom Agaricus sylvaticus can prevent the onset of atheroma plaques in hipercholesterolemic rabbits

Since the involvement of free radicals in the pathophysiology of atherosclerosis was proposed, antioxidant supplementation arose as a potential strategy for the management of this disease. Thus, we decided to investigate the potential benefit of a natural antioxidant--rich edible mushroom (Agaricus sylvaticus) on the prevention of atherosclerosis. New Zealand rabbits underwent atherosclerosis induction by feeding a cholesterol--enriched chow (Group A), while Group B simultaneously received edible mushroom A. sylvaticus water solution. Control group received standard rabbit chow only (Group C). At the end of 10 week treatment period serum samples were drawn for lipid profile, uric acid, thiobarbituric acid reactive substances (TBARS), and total antioxidant status (TAS). The area of aorta arteries taken by atheroma plaques was evaluated. Groups A and B presented higher cholesterol levels (p< 0.01) and reduced TAS (p<0.01), when compared to the Group C. However, TBARS and uric acid levels for Group B animals' were reduced, in comparison to Group A (p<0.05), and equals to group C. Moreover, animals from group A developed extensive atherosclerotic areas (47.0+/-14.0%), and that was prevented by the supplementation of A. sylvaticus (6.6+/-2.9%, p<0.01). Data suggested that A. sylvaticus can prevent the development of atherosclerosis in spite of hipercholesterolemia.

Comparison of the Polar S810i monitor and the ECG for the analysis of heart rate variability in the time and frequency domains

The aim of the present study was to compare heart rate variability (HRV) at rest and during exercise using a temporal series obtained with the Polar S810i monitor and a signal from a LYNX(R) signal conditioner (BIO EMG 1000 model) with a channel configured for the acquisition of ECG signals. Fifteen healthy subjects aged 20.9 +/- 1.4 years were analyzed. The subjects remained at rest for 20 min and performed exercise for another 20 min with the workload selected to achieve 60% of submaximal heart rate. RR series were obtained for each individual with a Polar S810i instrument and with an ECG analyzed with a biological signal conditioner. The HRV indices (rMSSD, pNN50, LFnu, HFnu, and LF/HF) were calculated after signal processing and analysis. The unpaired Student t-test and intraclass correlation coefficient were used for data analysis. No statistically significant differences were observed when comparing the values analyzed by means of the two devices for HRV at rest and during exercise. The intraclass correlation coefficient demonstrated satisfactory correlation between the values obtained by the devices at rest (pNN50 = 0.994; rMSSD = 0.995; LFnu = 0.978; HFnu = 0.978; LF/HF = 0.982) and during exercise (pNN50 = 0.869; rMSSD = 0.929; LFnu = 0.973; HFnu = 0.973; LF/HF = 0.942). The calculation of HRV values by means of temporal series obtained from the Polar S810i instrument appears to be as reliable as those obtained by processing the ECG signal captured with a signal conditioner.

Risk factors of childhood asthma in Sao Jose do Rio Preto, Sao Paulo, Brazil

BACKGROUND

Epidemiological studies have shown increased prevalence of asthma over the last decades and a considerable variation in these rates between different countries, mainly developed. Changes in lifestyle of different populations could explain the increasing prevalence of asthma and its different rates in different communities.

OBJECTIVES

A case-control study was conducted to investigate some risks factors associated to asthma in schoolchildren in São José do Rio Preto, São Paulo, Brazil.

CASUISTIC AND METHODS

A total of 3793 self-administered written questionnaire (WQ) was filled in by parents of 6-7-year-old schoolchildren, applying the International Study of Asthma and Allergies in Childhood (ISAAC) protocol. Additionally, was added a supplementary WQ evaluating risk factors: gender, personal history of rhinitis and atopic eczema, familial history of atopy, older siblings, day care, breastfeeding, and exposure to pets and to cigarette smoking. Children whose parents responded affirmatively to question 'Has your child had wheezing in the past 12 monthsquest;' were identified as having current asthma.

RESULTS

The prevalence of current asthma was 18.3%. In multivariate analysis the following risk factors were associated with asthma: rhinitis (OR = 10.6; 95% CI = 8.27-13.56), atopic eczema (OR = 1.54; 95% CI = 1.00-2.35), father with asthma (OR = 3.49; 95% CI = 1.83-6.67), mother with asthma (OR = 1.84; 95% CI = 1.11-3.05), current exposure to pets (OR = 1.83; 95% CI = 1.45-2.32) and passive tobacco smoking exposure (OR = 1.43; 95% CI = 1.12-1.83).

CONCLUSIONS

Our results show that genetic background, environmental factors and the presence of co-morbidities such as rhinitis and atopic eczema are associated to the genesis of asthma in Brazilian schoolchildren.

Self-drainage lymphatic technique

About 100 million people around the world have lymphedema; however, a large number do not have access to any kind of treatment. The current study reports on a technique of lymphatic self-drainage. The method consists of utilizing rods, bars, or any cylindrical object that rolls smoothly over the skin area to be drained. During this gliding motion a pressure of around 30 to 40 mm Hg should be exerted by the patient. The classical concepts of lymphatic drainage should be followed. This new method was subjected to a lymphoscintigraphic, anthropometric, and clinical evaluation demonstrating its usefulness in treating lymphedema.

Dynamic cardiomyoplasty: long-term clinical results in patients with dilated cardiomyopathy

BACKGROUND

Dynamic cardiomyoplasty has been considered to be an effective method of surgical treatment of patients with end-stage heart failure, and is an alternative to heart transplantation.

METHODS

We critically evaluated the long-term course of 52 patients with dilated cardiomyopathy who underwent dynamic cardiomyoplasty and were followed-up for up to 110 months.

RESULTS

Dilated cardiomyopathy was due to undetermined cause in 42 patients (80.8%), Chagas disease in 8 (15.4%), viral infection in 1 (1.9%), and peripartum cardiomyopathy in 1 (1.9%). In the nonchagasic group the survival rates were 79.5% +/- 6.1%, 67.8% +/- 7.1%, 53.7% +/- 8.3%, 49.9% +/- 8.3%, 14.9% +/- 12.2%, and 14.9% +/- 12.2%, respectively, at 12, 24, 48, 60, 80 and 110 months of follow-up. In the chagasic patients the survival rates were 37.5% +/- 17.1%, 12.5% +/- 11.7%, 12.5% +/- 11.7% and 0%, respectively, at 12, 24, 48, and 60 months of follow-up, making chagasic cardiomyopathy a possible contraindication for dynamic cardiomyoplasty.

CONCLUSIONS

There was no correlation between the clinical improvement and hemodynamic data. Ventricular fibrillation was a frequent cause of immediate and late death, suggesting the need for prophylactic use of antiarrhythmic drugs or implantable cardioverter/ defibrillators.

[Age of appearance and disappearance of rolandic spikes of 160 children treated in ambulatory. Actuarial study]

This study aims to determine the age at which the rolandic spikes (RS) appear and disappear in routine EEGs.

METHOD

It has been carried out a hospital based prospective study of 412 EEGs records of 160 children who had been assisted at the neuropediatric out-patient department during the period between March, 1989 and March, 1998. Recordings were made on 8-channel instruments and 10/20 system has been to place the electrodes. The children have been divided into 4 groups, according to their age (1 to 4; 5 to 8; 9 to 16; 1 to 16), and the actuarial curve method has been used to show the disappearance of the rolandic spikes.

RESULTS

RS distribution between boys and girls has been 64/36 ratio. RS have been found at average age of 7 years (boys, 7.2 and girls, 6.6). In a small group of children with normal EEGs previous to the RS appearance, the average age has been 6.8 years old. After this 7-year follow up period, the percentage of patients free from RSs was 60% for 1 to 4 year old group at admission; 84% for the 5 to 8 year old group and for the 9 to 16 year old group. For the total group (1 to 16 year old), the percentage of those free from RSs after this 7 year follow up period was 78%.

CONCLUSION

This study shows that RSs appear at the average age of 7 years old, and are likely to disappear up to the end of a 7-year follow up period, independently on the appearance age.

[Nutritional status of surgical patients without apparent nutritional compromise]

Nutritional status of 80 preoperative patients from programmed surgeries of hernias and lithiasis was studied by anthropometric and biochemical parameters. Nutritional deficiencies related to pathology were not expected in these patients. Results were as follows: 77% of the population showed overweight, being 15% obese. Prevalent protein intake, evaluated by the urea nitrogen/creatinine ratio, was adequate in 87.5% of the patients; however, patients presented 72% of albumin, 52% of prealbumin and 50% of RBP below reference values. Transferrin, ceruloplasmin, alpha 2-macroglobulin and haptoglobin were not decreased. Assessment of vitamin A, carotenes and vitamin C showed plasmatic levels below reference values in 16% of the patients for vitamin A, 5% for carotenes and 27% for vitamin C. Respect to calcium status, data of calcium/creatinine ratio show deficiency in 45% of the population. Respect to iron, the nutritional status was in general adequate, patients at risk being 5% by Htc, 11% by Hb, 5% by TS% and 12.5% by FEP, women showed over twice abnormal values than men. Although some isolated relations were observed, in this population sex, age and pathology were variable that did not affect in a relevant way the nutritional status. In spite of the individual analysis of each nutrient did not show important deficiencies, the analysis by patient showed that only a few of them (7%) presented an optimal biochemical profile with all the studied parameters within the reference values.

Immunoglobulin M serum levels in females and pups of southern elephant seal (Mirounga leonina) during the suckling period

This paper reports Immunoglobulin M (IgM) levels in serum samples from eight female-pup pairs of southern elephant seals (Mirounga leonina), at King George Island, Antarctica. IgM levels were determined on sera obtained from sequential sampling throughout the suckling period (approximately 23 days). The IgM concentration in southern elephant seal serum was measured by single radial immunodiffusion on agarose plates. Female IgM levels (123.5-613.0 mg/dL, n = 8) were significantly higher than pup levels (5.9-123.6 mg/dL, n = 8). Both groups showed an increasing trend throughout the entire suckling period, with significant differences in relation to stages of lactation. Pup IgM levels on the first day of life (mean +/- SD, 7.6 +/- 2.9 mg/dL, n = 3) suggest that endogenous synthesis takes place before birth.

Mapping of bovine pericardium: physical and histopathologic tests

BACKGROUND AND AIMS OF THE STUDY

This study was performed to identify the physical and histopathologic characteristics of different sections of glutaraldehyde-tanned bovine pericardium.

METHODS

Ten pericardial sacs were obtained from animals aged from 18 to 36 months. Physical tests included shrinkage and mechanical resistance (rupture, elongation, tenacity index). Collagen and elastic fibers were evaluated in Gomori's trichrome-stained sections, hematoxylin and eosin, by PAS and Verhoeff's method. Studied areas were proximal to the great arteries, and the right atrial, right ventricular, left ventricular and left atrial regions.

RESULTS AND CONCLUSIONS

Results showed that bovine pericardium does not have enough regional differences to identify any single region for bioprosthesis manufacture. However, histopathology showed better preservation of collagen and elastic fibers in the right ventricular region, implying that this area is more adequate as bioprosthetic material.

[The epidemiology of Chagas' disease in a rural area of the city of Teresina, Piauí, Brazil]

In the rural areas of Teresina, 129 triatomines were captured distributed in (a) artificial ecotopes; a house with one Triatoma brasiliensis, one Panstrongylus geniculatus, Rhodnius pictipes, and one Rhodnius prolixus and in a uninhabited chicken house (7 Rhodnius nasutus). (b) Natural ecotopes; Pahus Orbignya martiana (41 Rhodnius neglectus, 33 Rhodnius prolixus and 41 Rhodnius nasutus) and Copernicia cerifera (3 Rhodnius neglectus). The 22.6% of captured triatomines were infected by flagellates similar to Trypanosoma cruzi. Twenty-eight sylvatic mammals were captured and examined. Seven Didelphia albiventris, 2 Rattus rattus and a Tamandua tetradactyla were infected with flagellates. The flagellates found in both triatomines and mammals were morphologically indistinguishable from Trypanosoma cruzi. Serology by the indirect immunofluorescence test for Chagas disease revealed two positive seroreactions of positivity among 123 inhabitants examined.