Real-Time Analysis of the Respiratory Flow Through a Valved Holding Chamber.

Background: The ability of patients to take, correctly and regularly, aerosol treatments is a key for good control of asthma and chronic obstructive pulmonary disease. Devices that help to improve inhalation technique could train the patient to take their medication properly, reducing risk of exacerbations. In this study we evaluate a new device that by recording real-time respiratory flow into the valved holding chamber (VHC) mouthpiece, could be used to improve patient technique. Methods and Results: Using computational fluid dynamics analysis we demonstrated that compared to a mouthpiece with no flow probe, the presence of a probe modifies the flow profile and velocity regardless of the probe shape or position. During flow measurement using a SDP610 pressure sensor (Sensirion, Switzerland), all probes can accurately record adult and child respiratory patterns. Resistance was determined from the back pressure generated by the VHC with or without probes; and resistance was not impacted by the probes. Aerodynamic particle size distribution and drug delivery measurement were assessed using the United States Pharmacopeia throat model (Copley Scientific, UK), next generation impactor (NGI; Copley Scientific), and a breath simulator (BRS200; Copley Scientific). To test different formulations, these experiments were performed with fluticasone propionate (Flixotide®; GSK, UK), salbutamol (Ventolin®; GSK), and beclomethasone dipropionate (BDP) (QvarSpray®; GSK). Depending on the molecule or the probe configuration, we noticed a decrease of the emitted doses, fine particle deposition, mass median aerodynamic diameter, but no significant change in the mass of drug delivered. A decrease in the fine particle fraction (FPF) was observed in most testing conditions. However, a slight increase was noticed for two conformations with BDP (round and close [Rc] and diamond and far [Df]) and salbutamol (Rc and round and far [Rf]). Conclusion: By inserting a flow probe directly into the mouthpiece of a VHC we could perform real-time analysis of respiratory flow during the VHC use without disturbing drug delivery, or increasing resistance.

New insights into the evolution, hormonal regulation, and spatiotemporal expression profiles of genes involved in the Gfra1/Gdnf and Kit/Kitlg regulatory pathways in rainbow trout testis.

The present study aimed to investigate whether the Gfra1/Gdnf and/or Kit/Kitlg regulatory pathways could be involved in the regulation of spermatogonial cell proliferation and/or differentiation in fish. Homologs of the mammalian gfra1, gdnf, kitr, and kitlg genes were identified in gnathostomes and reliable orthologous relationships were established using phylogenetic reconstructions and analyses of syntenic chromosomal fragments. Gene duplications and losses occurred specifically in teleost fish and members of the Salmoninae family including rainbow trout (Oncorhynchus mykiss) and Atlantic salmon (Salmo salar). Some duplicated genes exhibited distinct spatiotemporal expression profiles and were differently regulated by hormones in rainbow trout. Undifferentiated type A spermatogonia expressed higher levels of kitrb and kitra2 making them possible target cells for the gonadal kitlgb and somatic kitlga before the onset of spermatogenesis. Interestingly, gdnfa and gdnfb ohnologous genes were poorly expressed before the onset of spermatogenesis. The expression level of gdnfb was correlated with that of the vasa gene suggesting that the late increased abundance of gdnfb during spermatogenesis onset was due to the increased number of spermatogonial cells. gfra1a2 was expressed in undifferentiated type A spermatogonia whereas gfra1a1 was mainly detected in somatic cells. These observations indicate that the germinal gdnfb ligand could exert autocrine and paracrine functions on spermatogonia and on testicular somatic cells, respectively. Fsh and androgens inhibited gfra1a2 and gdnfb whereas gfra1a1 was stimulated by Fsh, androgens, and 17α, 20ß progesterone. Finally, our data provide evidences that the molecular identity of the male germ stem cells changes during ontogenesis prior to spermatogenesis onset.