STAT5 Is an Ambivalent Regulator of Neutrophil Homeostasis

BACKGROUND: Although STAT5 promotes survival of hematopoietic progenitors, STAT5-/- mice develop mild neutrophilia. METHODOLOGY/PRINCIPAL FINDINGS: Here, we show that in STAT5-/- mice, liver endothelial cells (LECs) autonomously secrete high amounts of G-CSF, allowing myeloid progenitors to overcompensate for their intrinsic survival defect. However, when injected with pro-inflammatory cytokines, mutant mice cannot further increase neutrophil production, display a severe deficiency in peripheral neutrophil survival, and are therefore unable to maintain neutrophil homeostasis. In wild-type mice, inflammatory stimulation induces rapid STAT5 degradation in LECs, G-CSF production by LECs and other cell types, and then sustained mobilization and expansion of long-lived neutrophils. CONCLUSION: We conclude that STAT5 is an ambivalent factor. In cells of the granulocytic lineage, it exerts an antiapoptotic function that is required for maintenance of neutrophil homeostasis, especially during the inflammatory response. In LECs, STAT5 negatively regulates granulopoiesis by directly or indirectly repressing G-CSF expression. Removal of this STAT5-imposed brake contributes to induction of emergency granulopoiesis.Journal ArticleResearch Support, Non-U.S. Gov'tinfo:eu-repo/semantics/publishe

Evolution des pressions en oxygène et en dioxyde de carbone et du pH du sang artériel pendant la croissance

peer reviewedaudience: researcher, professiona

Efficacy of ivermectin and levamisole against immature Dictyocaulus viviparus in cattle

Eighteen calves aged approximately three months were each infected with Dictyocaulus viviparus larvae at a rate of 30/kg bodyweight. Seven days later they were randomly allocated to three groups of six animals. Calves of group 1 were controls. Calves of group 2 were given levamisole at a dose rate of 10 mg/kg and calves of group 3 were given ivermectin at a dose rate of 200 micrograms/kg. The anthelmintic activity of these two drugs was compared using clinical, functional, parasitological and pathological parameters. The results showed that the efficacy of ivermectin, given at a therapeutic dose, against immature D viviparus was higher than that of levamisole, given at double the recommended dos

Growth-Related Changes in the Pulmonary Function of Goats

Growth-related changes in pulmonary function values were investigated in 20 healthy French Alpine goats, aged between 20 and 550 days, weighing 7-55 kg. Pulmonary ventilation, mechanics of breathing and arterial oxygen tension were measured using standardized techniques and methods adapted for goats of different body sizes. The Ppl values and the tI/tTOT ratio showed no significant changes with age and body size. The ventilation values (Vt, Ve, mVI and mVE) increased linearly with growth. There was a significant correlation of age and body weight with dynamic lung compliance (Cdyn), total pulmonary resistance (RL), viscous work of breathing (Wvis tot) and minute viscous work (Wvis min) throughout the age range studied. Cdyn, Wvis tot and Wvis min increased and RL decreased with age and body weight. Arterial blood gases (PaO2 and PaCO2) did not show significant changes over the age range studied. Regression equations for each pulmonary function parameter are given with body weight as the independent variable. Data for the mechanics of breathing were compared with those elsewhere for cattle, horses, man and dogs

Respiratory and Pulmonary Haemodynamic Changes During Experimental Organophosphate Poisoning in Goats

Five French Alpine goats received 2 mg kg-1 of dichlorvos (DDVP) by intravenous injection and 0.15 mg kg-1 of atropine sulphate 5-10 min later. Ventilatory mechanics, gas exchanges, pulmonary haemodynamics and pulmonary vascular resistance (PVR) were measured before treatment, 5 min after DDVP injection and 5 min after atropine injection. Within 2 min of DDVP administration, all the goats showed acute respiratory distress, excitation and slight muscle fasciculations. A post-inspiratory pause was recorded in 3 goats. Hypersecretion of saliva or nasal discharge was not observed. Dynamic compliance and heart rate decreased significantly and total pulmonary resistance, pulmonary artery and wedge pressures increased significantly. On the other hand, minute ventilation, arterial oxygen and carbon dioxide tensions were not significantly altered by DDVP. Atropine treatment reversed all the clinical and functional parameters, with the exception of the central nervous and muscular signs, which disappeared within 12 h. It was concluded that experimental DDVP toxicosis induced changes in the mechanics of breathing and pulmonary haemodynamics associated with diffuse bronchoconstriction and cardiac insufficiency respectively