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Biomedical subjects

S Carrasco

Publications and source records attributed to S Carrasco.

23 records · Page 2Linked to original sources
PubMedDate not supplied

Reproducibility of heart rate variability from short-term recordings during five manoeuvres in normal subjects.

PRIMARY OBJECTIVE: Due to limited and contradictory information available, the reproducibility of temporal and spectral measurements of heart rate variability from short-term recordings was evaluated in normal subjects during supine, controlled breathing, standing, exercise and recovery conditions. METHODS AND PROCEDURES: Five-minute tachograms from 11 individuals were obtained during the specified manoeuvres, and repeated three times in a five day period. Besides temporal and spectral indexes, the central frequencies were also computed. MAIN OUTCOMES AND RESULTS: The ANOVA presented non-significant differences among the repetitions for any of the parameters studied. Most intra-class correlation coefficients were over 0.68. The central frequency of the low component diminished during the manoeuvres. CONCLUSIONS: In healthy individuals, the temporal and spectral measurements of the heart rate variability from short-term records are stable in a five day period for the manoeuvres studied. Central frequencies of the spectral components might be used as indexes of the autonomic activity.

Adult↗
PubMedDate not supplied

Comparison of the heart rate variability parameters obtained from the electrocardiogram and the blood pressure wave.

Four temporal and four spectral parameters of heart rate variability were compared after they were computed with two different time series generation methods: the RR intervals and the numerical values of heart rate provided by the Finapres. Recordings were obtained from 10 healthy subjects throughout five experimental conditions: supine, standing, controlled breathing, exercise and recovery. The mean and the RMS value of successive differences showed significant differences between the two methods. The spectral parameters were statistically different only during standing and exercise. The larger high frequency component and the lower HF/LF ratio by the Finapres method, observed during exercise, can be explained by the higher breathing influence on the peak-to-peak pressure intervals, in relation to RR intervals. Therefore, the high frequency component within mechanic intervals could possibly reflect the non-neural respiratory influence. In conclusion, values of heart rate provided by the Finapres are not completely interchangeable with those obtained from the ECG during the studied conditions.

Adult↗
PubMedDate not supplied

[Evaluation of counterimmunoelectrophoresis with antigens of icterohaemorrhagiae and patoc serovars in the serodiagnosis of human leptospirosis].

Counterimmunoelectrophoresis (CIE) was applied on paired sera from 135 patients with leptospirosis and on 69 sera from a control group. The sera from patients were subdivided in 4 groups according to the results obtained by the Microscopic Agglutination Test (MAT). The first samples sera from 58 patients were non reagent by MAT. Six monthly samples of sera were taken from 7 patients to follow-up and to determine the level of agglutinin and precipitin antibodies present using MAT and CIE. Serovars icterohaemorrhagiae and patoc were used as antigens. Three types of antigens were compared, 1) Triton-X-100 extracted; 2) heat extracted and 3) a pool of them. The CIE using icterohaemorrhagiae derived antigens types agreed with MAT in 92.64, 92.64 and 94.11% of the leptospirosis sera. The patoc antigens types reacted with the control group in 7.24, 86.95 and 84.05% of the samples, and consequently were eliminated from the present study. The icterohaemorrhagiae CIE reaction become positive earlier than MAT negative sera, and reverted to negative earlier in the follow-up samples from the patients. The CIE was sensitive and specific, gave rapid results and was easy to perform.

Agglutination Tests↗