Biomedical subjects
Jean-Charles Glérant
Publications and source records attributed to Jean-Charles Glérant.
Comparison of 2 maintenance doses (100 microg vs 200 microg) in Hymenoptera venom immunotherapy: influence of the maintenance dose on the immunologic response.
BACKGROUND: In Hymenoptera venom immunotherapy, the maintenance dose is usually 100 microg. However, persistent systemic reactions to sting challenges could be treated by an increase in the maintenance dose to 200 microg with success, suggesting greater efficiency. OBJECTIVE: To compare the effects of 2 monthly maintenance doses (100 microg vs 200 microg) on skin test sensitivity and venom specific IgE antibody levels. METHODS: Twenty-two patients receiving Vespula venom immunotherapy were enrolled in this retrospective study. After rush therapy, the 100-microg maintenance dose initially administered was maintained (group 1, n = 13) or was increased to 200 microg (group 2, n = 9). RESULTS: Levels of venom specific IgE antibody and skin test results measured before the onset of immunotherapy were comparable in both groups. Unlike in group 1, a maintenance dose of 200 microg resulted in significant decreases in venom specific IgE antibody levels and skin test sensitivity. CONCLUSIONS: Increasing the monthly maintenance dose to 200 microg results in a greater degree of change in venom specific IgE antibody levels and skin test sensitivity than when maintaining a 100-microg dose. Our data strengthen those of previous clinical studies showing the usefulness of a 200-microg maintenance dose in the case of clinical failure of a 100-microg dose.
Effects of intermittent negative pressure ventilation on effective ventilation in normal awake subjects.
RATIONALE: Previous studies have shown that an increase in inspiratory pressure during nasal intermittent positive pressure ventilation (IPPV) does not result in increased effective minute ventilation (E) due to glottic interference. STUDY OBJECTIVES: To test the consequences of increases in negative pressure ventilation (NPV) on V(E). MATERIAL AND METHODS: Eight healthy awake subjects underwent NPV delivered by an iron lung. First, NPV was started at a respirator frequency (f) of 15 cycles per minute with an inspiratory negative pressure (INP) of - 15 cm H(2)O (F15-P15). Then, f was increased to 20 cycles per minute and INP was kept at - 15 cm H(2)O. Next, f was kept at 20 cycles per minute and INP was reduced to - 30 cm H(2)O (F20-P30). Finally, f was decreased to 15 cycles per minute and INP was kept at - 30 cm H(2)O. At each step and for each breath, effective tidal volume (VT), V(E), and end-tidal carbon dioxide pressure were measured. In three subjects, the glottis width was assessed using fiberoptic bronchoscopy. RESULTS: From spontaneous breathing to the first step of NPV (F15-P15), we observed an inhibition of the phasic inspiratory diaphragmatic electromyogram concomitant to a significant increase in V(E) (p < 0.0005). For the group as a whole, the increase in mechanical ventilation (from F15-P15 to F20-P30) resulted in significant increases in VT and V(E) leading to hypocapnia (p < 0.0005). Moreover, the glottis width did not decrease with the increase in mechanical ventilation. CONCLUSIONS: We conclude that in normal awake subjects, NPV allowed a significant increase in V(E). These results differ from those previously obtained with nasal IPPV in which the glottic width interferes with the delivered mechanical ventilation.