Mucus threads from surface goblet cells clear particles from the airways.

BACKGROUND: The mucociliary clearance system driven by beating cilia protects the airways from inhaled microbes and particles. Large particles are cleared by mucus bundles made in submucosal glands by parallel linear polymers of the MUC5B mucins. However, the structural organization and function of the mucus generated in surface goblet cells are poorly understood. METHODS: The origin and characteristics of different mucus structures were studied on live tissue explants from newborn wild-type (WT), cystic fibrosis transmembrane conductance regulator (CFTR) deficient (CF) piglets and weaned pig airways using video microscopy, Airyscan imaging and electron microscopy. Bronchoscopy was performed in juvenile pigs in vivo. RESULTS: We have identified a distinct mucus formation secreted from the surface goblet cells with a diameter less than two micrometer. This type of mucus was named mucus threads. With time mucus threads gathered into larger mucus assemblies, efficiently collecting particles. The previously observed Alcian blue stained mucus bundles were around 10 times thicker than the threads. Together the mucus bundles, mucus assemblies and mucus threads cleared the pig trachea from particles. CONCLUSIONS: These results demonstrate that normal airway mucus is more complex and has a more variable structural organization and function than was previously understood. These observations emphasize the importance of studying young objects to understand the function of a non-compromised lung.

The microsurgical training programme in Gothenburg, Sweden: early experiences.

OBJECTIVE: Microsurgical techniques are increasingly used in routine surgical practice as well as in biomedical research. The training opportunities at standardised training courses are limited, and no microsurgical training facility or programme existed in Scandinavia before 2013. METHODS: A microsurgery laboratory was set up and two different courses were started, aiming separately at biomedical researchers and surgeons. The course for biomedical researchers teaches basic microsurgical skills such as vessel isolation, cannulation, and arterial microvascular suture under magnification. The more advanced course for surgeons focuses on various techniques of microvascular and nerve anastomosis. Both courses use a combination of theory and practice, with emphasis on the practical part, the course for surgeons also includes clinically relevant information. RESULTS: Twelve 5-day courses using both non-living models and exercises on laboratory animals have been conducted and attended by 49 researchers and 44 surgeons. The organisation and the programme of the training courses as well as 'The 4E concept' behind the course (educational curriculum, equipment, ergonomy, and evaluation) are further detailed. CONCLUSIONS: We have successfully established the first training laboratory and series of microsurgical training courses in Scandinavia at two different levels. The experience from the first 12 courses shows the need for this type of structured training, and confirms that the microsurgical education curriculums needs to be adapted to participants' prerequisites and expectations, and various difficulty levels should be considered.

Metoprolol, but not atenolol, reduces stress induced neuropeptide Y release in pigs.

OBJECTIVES: To explore if ß-adrenergic receptors in the brain are involved in acute and delayed cardiovascular responses to a brief emotional stress, by comparing the effects of the ß1-blockers metoprolol (lipophilic) and atenolol (hydrophilic). DESIGN: Male dominant pigs, singleliving, freely moving, with telemetric recordings of intra-arterial pressure and ECG and assay of plasma levels of the adrenergic cotransmitter neuropeptide Y (NPY), were confronted with four alien pigs for three minutes at weekly intervals. Weeks 1 and 4 were controls, in weeks 2 and 3 randomized crossover treatment with metoprolol or atenolol were given. RESULTS: The confrontation caused instant and transient tachycardia and more prolonged effects in terms of increased plasma NPY levels, increased arterial pressure and reduced cardiac vagal activation. The two ß-blockers inhibited the tachycardia equally, but only metoprolol reduced the prolonged effects. CONCLUSIONS: Emotionally induced sympathetic activation involves peripheral release of NPY causing a prolonged increase of arterial pressure and a reduction of cardiac vagal activity. These effects are prevented by central nervous ß-adrenoceptor blockade.