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The release of the growth hormone in the basal state and in response to strenuous exercise was studied in a group of 15 hypertensive adolescents receiving clonidine therapy and in a control group of 17 untreated adolescents of which ten were hypertensive volunteers and seven were healthy normotensive volunteers. Mean basal growth hormone in clonidine-treated adolescents was 2.8 ± 0.50 S.E.M. ng/ml, compared to 2.7 ± 0.48 ng/ml in untreated adolescents. Following exercise stimulation, mean growth hormone was 14.8 ± 3.1 S.E.M. ng/ml in the treated group and 13.5 ± 2.8 ng/ml in the untreated group. Growth hormone release is regulated by α-adrenergic receptor stimulation. Clonidine acts centrally by α-adrenergic stimulation. However, this study demonstrates no effect of chronic clonidine therapy on growth hormone release. [ABSTRACT FROM AUTHOR]

Antibiotics are known to bind to whole cystic fibrosis sputum. However, the composition of sputum varies from one patient to another, making the interpretation of binding studies difficult. This problem has been examined by standardising the macromolecule concentration of sputum from four cystic fibrosis patients and adding tobramycin or ceftazidime directly to the sputum components. Binding to mucin-rich and DNA-rich fractions of sputum was also studied before and after DNase treatment of these fractions. These studies indicated that (i) the degree of tobramycin binding is dependent on the sputum macromolecule concentration, (ii) a significant proportion of tobramycin is bound even at concentrations of 100 mg/l of drug, (iii) tobramycin binds to both the mucin rich fraction and the DNA rich fraction of sputum and (iv) ceftazidime binding to sputum is negligible. Our data indicate that there is a need to standardise sputum in antibiotic binding studies and they provide another rationale for favouring the use of ceftazidime over aminoglycosides in infectious exacerbations of cystic fibrosis caused by Pseudomonas aeruginosa. [ABSTRACT FROM AUTHOR]

The activities of the newer antipseudomonal agents cefsulodin, ceftazidime, U-63196, aztreonam and piperacillin were compared, together with azlocillin, carbenicillin, ticarcillin and tobramycin against 98 strains of . On all of the 43 isolates from cystic fibrosis patients and the 55 strains from other chronically infected patients, ceftazidime (MIC: 5·0 and 2·8 mg/I respectively) and cefsulodin (MIC: 8·2 and 3·1 mg/l) were the most active cephalosporins, and U-63196 the least active (MIC: 40·1 and 46·1 mg/I). A high incidence of resistance (23 of 55 strains) to tobramycin was found only in the non-cystic fibrosis isolates. The activity of the other agents was comparable in the cystic fibrosis and non-cystic fibrosis isolates. MIC for aztreonam were 15·8 and 13·6 mg/l. Piperacillin was the most active penicillin in both populations (MIC: 25·8 and 21·8 mg/l). Cross resistance was demonstrated in both populations for the penicillin compounds. [ABSTRACT FROM PUBLISHER]

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Acute exacerbations of Pseudomonas aeruginosa lung infections were treated with ceftazidime by continuous infusion in 17 adult patients with cystic fibrosis at home. Ceftazidime was delivered via an infusion pump and the effects of this 3 week home intravenous antibiotic treatment (HIVAT) were prospectively studied over a 2 year period. Patients with cystic fibrosis (eight male and nine female patients; mean age 26.9 +/- 7.6 years, range 15-52 years), received a total of 33 courses of continuous ceftazidime (100 mg/kg/24 h). Clinical data were collected at the start, the end and 4-6 weeks after the end of treatment in 12 patients. Ceftazidime pharmacokinetic data during continuous infusion were obtained from ten patients. The treatment was supervised by the clinician without home visits. All 25 clinically evaluable courses in 12 patients proved efficacious. The mean duration of the courses was 21 days. The entire antibiotic course was administered at home in 88% of the courses. The other 12% was started for 2-3 days as an inpatient. Objective clinical parameters significantly improved. Clinical improvement was noted in 91% of the patients, and lasted at least until 4-6 weeks after the end of the treatment in 70%. The number of cultures positive for P. aeruginosa decreased significantly during antibiotic treatment. Bacterial count returned to pretreatment values 4-6 weeks after treatment. Multiple courses of ceftazidime monotherapy did not result in a lasting increase of ceftazidime-resistant pseudomonas strains. Total body clearance was 9.1 +/- 1.3 L/h. The steady-state ceftazidime serum concentration during continuous infusion was 28.4 +/- 5.0 mg/L. Sputum concentrations were in the range of 0.5-13 mg/L (3.9 +/- 4.0 mg/L). In conclusion, HIVAT with ceftazidime administered by continuous infusion proved clinically effective and did not result in an increase in lasting resistance. [ABSTRACT FROM AUTHOR]