Efficacy of pamidronate for osteoporosis in patients with cystic fibrosis following lung transplantation.

Lung transplantation with its attendant life-long immunosuppression contributes to bone loss and its sequelae, fractures and kyphosis, in patients with lung disease, many of whom already suffer from severe osteoporosis. Patients with cystic fibrosis (CF) are one of the most severely affected groups. We conducted a controlled, randomized, nonblinded trial of pamidronate (30 mg intravenously every 3 mo) with vitamin D (800 IU/d) and calcium (1 g/d) (n = 16) compared with vitamin D and calcium alone (n = 18, the control subjects) for 2 yr in 34 patients after lung transplant to improve bone mineral density (BMD). The treatment groups were similar in age, sex, baseline T-scores, renal function, hospitalization rates, immunosuppressant levels, change in lung function, and body mass index (BMI) over the study period. The patients treated with pamidronate gained 8.8 +/- 2.5% and 8.2 +/- 3.8% in spine and femur BMD after 2 yr in comparison to control subjects, who gained, on average (+/- SD), 2.6 +/- 3.2 and 0.3 +/- 2.2%, respectively (p 0.2). Measures of bone resorption were highest immediately after lung transplant and improved with both pamidronate and time. Measures of bone formation were very poor after lung transplant, but recovered in the first post-lung transplant year irrespective of therapy. We conclude that pamidronate was more effective than control in improving bone mineral density after lung transplantation in patients with CF and appears to be one of the most promising agents studied to date for posttransplant osteoporosis.

Increased rate of fractures and severe kyphosis: sequelae of living into adulthood with cystic fibrosis.

BACKGROUND: Osteoporosis occurs in patients with cystic fibrosis as they age, but its clinical implications are not well defined. OBJECTIVE: To determine the clinical effect of decreased bone mineral density in adults with cystic fibrosis and to assess possible clinical predictors of osteoporosis. DESIGN: Retrospective cohort study. SETTING: Academic cystic fibrosis center. PATIENTS: 70 adults with late-stage cystic fibrosis who were referred for lung transplantation. MEASUREMENTS: Bone mineral density was measured with dual-energy x-ray absorptiometry, patient-reported fracture events were confirmed by radiography, and kyphosis angles were measured by using the Cobb method. RESULTS: Mean bone mineral densities for the spine, femur, and total body were severely depressed in patients with cystic fibrosis, averaging 2 SDs below those of age-matched normal controls (P < 0.001). Patient interviews showed that 54 fractures had occurred over 1410 patient-years, and chest radiographs showed evidence of 14 additional rib and 62 additional vertebral compression fractures. The database (which covered 1410 patient-years) showed that fracture rates were approximately twofold greater in women with cystic fibrosis aged 16 to 34 years (P = 0.015) and men with cystic fibrosis aged 25 to 45 years (P = 0.04) than in the general population. Vertebral compression and rib fractures were 100- and 10-fold more common than expected, respectively (P < 0.001 for both comparisons). The mean kyphosis angle (+/- SD) for this group was markedly abnormal (44 +/- 14 degrees; 62% > or = 40 degrees) and probably contributed to diminished stature (mean height loss, 5.8 cm in men with cystic fibrosis and 5.9 cm in women with cystic fibrosis). Cumulative prednisone dose, body mass index, and age at puberty were the strongest predictors of bone mineral density. CONCLUSIONS: Osteoporosis is universal in adults with late-stage cystic fibrosis, and its complications include increased fracture rates and severe kyphosis.

Correlation of kinetic energy losses in high-energy collision-induced dissociation with observed peptide product ions.

In collision-induced dissociation, some of an incident parent ion's kinetic energy is converted into internal energy upon collision with a neutral target. The kinetic energy lost is related to the amount of internal energy deposited into any individual ion. To see dissociations of different critical energies on the same time scale, different amounts of internal energy need to be deposited. This should be reflected in the kinetic energy lost by the parent ion in the formation of different product ions. Variable amounts of energy loss in the formation of different peptide product ions are reported here. It is seen that different product ion types (b, y, a) show ordered patterns of energy losses. A greater energy loss is observed for the formation of b-type product ions than for y-type, and even greater energy losses are observed for the formation of a-type product ions. A very good correlation between ion type energy loss and ion mass is observed. Thus, measuring the energy losses in the formation of product ions may provide a means for classifying the product ion type.