[Assessment of muscular toxicity due to chemotherapy by cardio-pulmonary exercise testing]. / Évaluation de la toxicité musculaire de la chimiothérapie lors d'une épreuve fonctionnelle à l'exercice.

INTRODUCTION: Cardio-pulmonary exercise testing (CPET) is frequently used to assess aerobic capacity, to evaluate respiratory tolerance and to provide prognostic information. Therefore, CPET is often incorporated in the preoperative assessment of cancer patients. This clinical case report presents the preoperative assessment of a patient before thoracic surgery, in whom an important decrease of aerobic capacity was noted, possibly because of muscular toxicity linked to chemotherapy. CASE REPORT: This clinical case concerns a fit, 66-year-old man with a large cell carcinoma of the bronchus. He had received 2 cycles of adjuvant chemotherapy. Subsequently, a left pneumonectomy had been proposed and preoperative assessment performed. CPET showed no further increase in oxygen uptake after the first ventilatory threshold, in spite of increases in carbon dioxide output, minute ventilation and heart rate. Moreover, maximal oxygen uptake was low and there was a decrease of oxygen pulse at maximal effort. CONCLUSION: We suggest that the limitation of effort was due to a limitation of muscular oxygen extraction, which could be explained by possible muscular toxicity due to chemotherapy.

Local absorption measurement by laser-induced fluorescence.

The method consists of determining the local absorption of a tuned laser pulse between two points close together along the laser beam by measuring the fluorescence emitted from these two points. In this way a nonintrusive local and instantaneous sampling of the laser spectral intensity is achieved at these points where the system-absorption line and subsequent linear fluorescence emission-acts as an in situ spectrometer. Problems due to fluorescence efficiency, fluorescence trapping, and detector sensitivity that could be different for the two points are overcome by using a second beam emitted by the same pulsed laser running collinearly but in the opposite direction to the first beam and with a short delay. Finally a ratio between the two pairs of fluorescence signals provides the optical depth of the medium between the two points involved. Feasibility is demonstrated by the measurement of OH absolute concentration in a homogeneous premixed flame.

Direct measurement of OH local concentration in a flame from the fluorescence induced by a single laser pulse.

An alternative to the saturation approach is proposed to avoid the quenching dependence of the fluorescence intensity. The method allows direct absolute measurement of the local number density from a single laser shot. A mean quenching cross section of 5 x 10(-19) m(2) is deduced from the experiments, and a OH concentration profile through the flame is given.

Diffracted stimulated emission induced by two strong coherent crossed laser beams for concentration measurement.

Detecting the stimulated light is suggested rather than collecting the spontaneous emission due to radiative relaxation of the specie excited by a tuned laser pulse. A method is proposed to deviate a part of this stimulated emission from transmitted light under near saturation excitation conditions. Application to local and instantaneous concentration measurement is discussed.