Role of nitric oxide during hyperventilation-induced bronchoconstriction in the guinea pig

Beneficial effects of extended growth hormone treatment after hospital discharge in pediatric burn patients

OBJECTIVE

To study the efficacy of growth hormone given to severely burned children from discharge to 12 months after burn and for 12 months after the drug was discontinued.

SUMMARY BACKGROUND DATA

We have previously shown that low-dose recombinant human growth hormone (rhGH), given to children after a severe thermal injury, successfully improved lean muscle mass, bone mineral content, and growth. The aim of the present study was to investigate long-term functional improvements after treatment.

METHODS

Forty-four pediatric patients with over 40% total body surface area burns were studied for 24 months after burn. Patients were randomized to receive either rhGH (0.05 mg/kg body weight) or placebo. Height, weight, body composition, serum hormones, resting energy expenditure, cardiac function, muscle strength, and number of reconstructive procedures performed were measured during rhGH treatment and for 12 months after treatment was discontinued. Statistical analysis used Tukey's multiple comparison test. Significance was accepted at P < 0.05.

RESULTS

Height, weight, lean body mass, bone mineral content, cardiac function, and muscle strength significantly improved during rhGH treatment compared with placebo (P < 0.05). This treatment significantly increased GH, IGF-I, and IGFBP-3, whereas serum cortisol decreased (P < 0.05). The number of operative reconstructive procedures was significantly lower with rhGH (P < 0.05). Improvements in height, bone mineral content, and IGF-1 concentrations persisted after rhGH treatment (P < 0.05). No side effects with rhGH were observed.

CONCLUSIONS

Administration of rhGH for 1 year after burn was safe and improved recovery. These salutary effects continued after rhGH treatment was discontinued.

Role of airway endogenous nitric oxide on lung function during and after exercise in mild asthma

We hypothesized that nitric oxide (NO), a known mild bronchodilator that can be released by several cell types within pulmonary airways, might protect airways during exercise in asthmatic subjects. We studied 17 individuals with documented exercise-induced asthma (screening exercise evaluation) on 2 study days: after treatment with inhaled NO synthase inhibitor N(G)-monomethyl-l-arginine (l-NMMA; 2 ml of 25 mg/ml mist) and after treatment with saline vehicle. Pulmonary resistance (Rl, esophageal manometry) rose and forced expiratory volume in 1 s fell more after l-NMMA compared with saline treatment, suggesting a bronchoprotective role for NO at baseline. The rise in Rl seen after l-NMMA treatment was nearly completely reversed early in exercise, suggesting a non-NO-mediated bronchodilation. A slow rise in Rl during constant-load exercise and dramatic increase in Rl after exercise were the same on the 2 treatment days, indicating little role for NO in regulating airway function during and after exercise. We conclude that endogenous NO plays little role in regulating airway function during and after exercise in subjects with mild asthma.