Comparative effects of flavonoids on the growth, viability and metabolism of a colonic adenocarcinoma cell line (HT29 cells).

The aim of the present study was to compare the effect of five structural classes of flavonoids on the viability and metabolism of a colonic adenocarcinoma cell line (HT29 cells). The most prominent structural features of flavonoids favoring both their cytotoxic activity and their capacity to inhibit lactate release appear to be the desaturation of the 2, 3 bond and the position of attachment of the B ring. Indeed, flavonol and flavone are the most potent and, in both classes, the order of potency can be modulated by hydroxyl or methoxyl substituents. On the other hand, in our model, we did not find any correlation between flavonoid structure and their capacity to modulate cAMP level. This last point is discussed.

Does an acute COPD crisis modify the cardiorespiratory and ventilatory adjustments to exercise in horses?

The present study was conducted to understand better the mechanisms leading to the decrease in exercise capacity observed in horses suffering from chronic obstructive pulmonary disease (COPD). Five COPD horses were submitted to a standardized submaximal treadmill exercise test while they were in clinical remission or in acute crisis. Respiratory airflow, O2 and CO2 fractions in the respired gas, pleural pressure changes and heart rate were recorded, and arterial and mixed venous blood were analyzed for gas tensions, hemoglobin, and plasma lactate concentrations. O2 consumption, CO2 production, expired minute ventilation, tidal volume, alveolar ventilation, cardiac output, total pulmonary resistance, and mechanical work of breathing were calculated. The results showed that, when submaximally exercised, COPD horses in crisis were significantly more hypoxemic and hypercapnic and that their total pulmonary resistance and mechanical work of breathing were significantly higher and their expired minute ventilation significantly lower than when they were in remission. However, their O2 consumption remained unchanged, which was probably due to the occurrence of compensatory mechanisms, i.e., higher heart rate, cardiac output, and hemoglobin concentration. Last, their net anaerobic metabolism seemed to be more important.

Effect of a set stabled environmental control on pulmonary function and airway reactivity of COPD affected horses.

The aim of this study was to evaluate the respiratory function of horses affected with chronic obstructive pulmonary disease (COPD) when maintained in a barn on wood shavings and fed grass silage for a period of 6 weeks. The mechanics of breathing, blood gas analysis and bronchial reactivity were examined on five horses with COPD at the end of the environment-controlled period (Period B) and the results compared with values obtained after 2 months at pasture (Period A) and after the onset of clinical signs of acute crisis (Period C). The results showed that clinical and functional parameters were similar in healthy horses and in COPD horses placed on pasture or stabled and fed grass silage. Moreover, the bronchial reactivity of COPD horses at pasture was similar to the bronchial reactivity of healthy horses. COPD horses fed grass silage however presented a bronchial reactivity intermediate between those measured after Period A and Period C which suggested they would be more susceptible to develop bronchoconstriction when in contact with inhaled irritants.