RESUMO
It is now well recognized that a change in osmolarity of the periciliary fluid is a potent stimulus to airway narrowing and may be a common cause for provoking an attack of asthma. This has led to the use of nonisotonic aerosols to document bronchial hyperresponsiveness in patients with clinical asthma. These aerosols are generated by ultrasonic nebulizers, and the most commonly used are water, hyperosmolar sodium or potassium chloride, and dextrose. An increase in specific airway resistance of 100% or a reduction in FEV1 of 20% is considered as an abnormal response to these aerosols. There are a number of factors that affect the airway response to these aerosols, and these include the osmolarity of the solution and its ionic content and pH. In addition responses may be affected by a previous challenge or medication. It is not known precisely how these aerosols act to induce airway narrowing, but it is not by a direct action on smooth muscle. It is thought that a change in osmolarity of the airways causes the release of inflammatory mediators, which then act to narrow the airways. For this reason challenge by nonisotonic aerosols is different from challenge by histamine and methacholine and may be preferable for the diagnosis of asthma and assessment of its treatment.
Assuntos
Testes de Provocação Brônquica , Broncoconstrição/efeitos dos fármacos , Agonistas Adrenérgicos beta/farmacologia , Aerossóis , Testes de Provocação Brônquica/métodos , Bloqueadores dos Canais de Cálcio/farmacologia , Furosemida/farmacologia , Humanos , Soluções Isotônicas , Cloreto de Metacolina/farmacologia , Concentração OsmolarRESUMO
The biologic value and the cost of three commercial protein supplements were compared using casein as the control. Each product was fed to rats as the sole protein source supplying 10 percent of the energy in a semipurified diet. Nonfat dry milk was equal to casein in PER, but the PERs of low-fat soy powder and high-protein supplement were significantly lower than the PER of casein. Nitrogen balance was positive for all protein supplements, but low-fat soy powder was significantly lower than the others. cost comparison per gram of protein showed low-fat soy powder to be the least expensive, nonfat dry milk to be slightly higher in cost, and the high-protein supplement to be the most expensive.