A flow injection chemiluminescence method using Cr(III) as a catalyst for determining hydrogen peroxide. Application to H(2)O(2) determination in cultures of microalgae.

Flow injection analysis has been applied to the determination of hydrogen peroxide produced by some different species of microalgae. The method is based on the luminol-H(2)O(2) chemiluminescence reaction using Cr(III) as a catalyst. Optimum experimental conditions for the method have been studied and trace amounts of hydrogen peroxide determined with detection limits of 4 10(-8) mol/L. The method using Cr(III) was compared with that using horseradish peroxidase as the catalyst.

[The epidemiology of heart failure in the elderly]. / Epidemiología de la insuficiencia cardíaca en el anciano.

OBJECTIVE: To find the prevalence and aetiology of chronic cardiac failure (CCF) among elderly people in a health area. DESIGN: Retrospective, crossover study. SETTING: Delicias Sur Health Centre, Zaragoza. PATIENTS AND OTHER PARTICIPANTS: A representative sample of the population over 65 registered at the Health Centre. Systematic random sampling: n = 1,635. MEASUREMENTS AND MAIN RESULTS: 104 cases of cardiac failure were identified, which corresponded to a 6.3% (+/- 0.01) prevalence. By age groups, prevalence was 4.5% (+/- 0.01) for the 65-74 group and 8.5% (+/- 0.02) for those over 75. Regarding aetiology, 50.9% was due to arterial hypertension, 21.2% coronary failure, 22.1% valvulopathies and 17.3% reason unknown. CONCLUSIONS: CCF prevalence in the community increases with age and in our ambit exceeds that found in other countries. Almost half the cases are related to arterial hypertension.