Faecal chymotrypsin concentrations in neonates with cystic fibrosis and healthy controls.

Specimens of meconium and random stools were collected sequentially from 25 healthy newborn babies over the first 8-14 days of life. The stool chymotrypsin concentrations increased from birth to a maximum at 4 days of age and then fell again over the next four days. The lowest individual stool concentrations either side of the four day peak were both, coincidentally, 120 micrograms/g stool. In a second group of 22 newborn babies suspected of meconium ileus and later confirmed to have cystic fibrosis, faecal chymotrypsin concentrations were all appreciably reduced. In eight babies, also with suspected meconium ileus but with negative sweat tests, chymotrypsin concentrations were within the healthy newborn range. Measuring faecal chymotrypsin concentrations is a reliable procedure for identifying pancreatic exocrine insufficiency in the newborn.

Gentamicin and tobramycin compared in the treatment of mucoid pseudomonas lung infections in cystic fibrosis.

18 children with cystic fibrosis and mucoid pseudomonas lung infection were treated with courses either of gentamicin plus carbenicillin, or tobramycin plus carbenicillin, with 2 children each receiving two courses. 10 courses of gentamicin at a dose of 9 mg/kg per day plus carbenicillin at 800 mg/kg per day, and 10 courses of tobramycin at 9 mg/kg per day plus carbenicillin at 800 mg/kg per day were given. There was clinical and x-ray improvement in both groups of children, but there was no difference between the therapeutic benefit of either regimen. Pseudomonas aeruginosa was not cultured at the end of treatment after 15 of the 20 courses, but it returned in all but one patient within 3 months. Neither ototoxicity nor renal damage with these high doses of aminoglycoside was detected. P. aeruginosa had not been eliminated when 9 of these patients earlier had received courses of gentamicin in a dose of 6 mg/kg per day plus carbenicillin at 800 mg/kg per day. The results show that P. aeruginosa can successfully be eliminated or suppressed with high-dose aminoglycoside plus carbenicillin, but such elimination is usually short lived.

Does that child really have cystic fibrosis?

A diagnosis of cystic fibrosis was incorrectly made after false-positive sweat tests in 14 children. 13 of these children had been tested at hospitals where it seems likely that sweat tests were not done very often. All the children had normal sweat-electrolyte values when the test was repeated at a regional paediatric centre where approximately 250 sweat tests are done each year. In 5 cases, detailed testing of pancreatic function was normal. None of the children had typical chest disease and only 2 had gastrointestinal symptoms. In the absence of the typical clinical features of the disease a diagnosis of cystic fibrosis should be made with extreme caution and only after meticulous testing of both sweat electrolytes and pancreatic function.

Reduction of bile acid loss in cystic fibrosis by dietary means.

On a 'normal' diet increased faecal bile acid excretion was found in 14 of 16 children with cystic fibrosis who had steatorrhoea, but excretion was normal in 2 such children without steatorrhoea. The 16 children with steatorrhoea took 3 regimens of diet and therapy: a 'normal' diet with pancreatic enzyme supplements, a diet of reduced long-chain triglycerides with added medium-chain triglycerides, and the same diet with added pancreatic enzyme supplements. On each of these three regimens steatorrhoea and faecal bile acid loss were significantly less than on no treatment, with the lowest excretions occurring on the diet of reduced long-chain triglycerides with added medium-chain triglycerides and pancreatic enzyme supplements. Although a reduction in steatorrhoea was nearly always accompanied by a decrease in bile acid excretion, the initial bile acid loss was very variable and could not be predicted for any given degree of steatorrhoea. This suggests that at least one other factor, possibly liver disease or bile acid pool size, influences bile acid loss in the faeces.

Elevated serum IgG4 levels in cystic fibrosis patients.

The quantitative measurement of the IgG subclass composition of the sera from sixteen patients with cystic fibrosis has revealed grossly elevated levels of IgG4 in seven patients. The possible significance of this observation is discussed in relation to recent reports of a high incidence of immediate-type hypersensitivity in such patients.