Elaine H. Mischler

Nutritional Benefits of Neonatal Screening for Cystic Fibrosis

BACKGROUND Many patients with cystic fibrosis are malnourished at the time of diagnosis. Whether newborn screening and early treatment may prevent the development of a nutritional deficiency is not known. METHODS We compared the nutritional status of patients with cystic fibrosis identified by neonatal screening or by standard diagnostic methods. A total of 650,341 newborn infants were screened by measuring immunoreactive trypsinogen on dried blood spots (from April 1985 through June 1991) or by combining the trypsinogen test with DNA analysis (from July 1991 through June 1994). Of 325,171 infants assigned to an early-diagnosis group, cystic fibrosis was diagnosed in 74 infants, including 5 with negative screening tests. Excluding infants with meconium ileus, we evaluated nutritional status for up to 10 years by anthropometric and biochemical methods in 56 of the infants who received an early diagnosis and in 40 of the infants in whom the diagnosis was made by standard methods (the control group). Pancreatic insufficiency was managed with nutritional interventions that included high-calorie diets, pancreatic-enzyme therapy, and fat-soluble vitamin supplements. RESULTS The diagnosis of cystic fibrosis was confirmed by a positive sweat test at a younger age in the early-diagnosis group than in the control group (mean age, 12 vs. 72 weeks). At the time of diagnosis, the early-diagnosis group had significantly higher height and weight percentiles and a higher head-circumference percentile (52nd, vs. 32nd in the control group; P=0.003). The early-diagnosis group also had significantly higher anthropometric indexes during the follow-up period, especially the children with pancreatic insufficiency and those who were homozygous for the deltaF508 mutation. CONCLUSIONS Neonatal screening provides the opportunity to prevent malnutrition in infants with cystic fibrosis.

Fatty Acid Abnormalities in Cystic Fibrosis

ABSTRACT: Fatty acids were measured by gas chromatography in lipid extracts of plasma and tissues obtained from three categories of 46 patients with cystic fibrosis. Low levels of the major essential fatty acid linoleate were found in plasma total lipids of patients who had malabsorption but not in those without evidence of steatorrhea. Circulating arachidonic acid was only slightly decreased, and the unusual triene reflecting pathologically altered fatty acid metabolism (20:3ω9) was generally not detected, nor was the triene/tetraene ratio abnormal except for in two patients. There was no correlation between plasma linoleate and age, clinical severity score, or vitamin E status. Decreased linoleate did correlate with two indices of malabsorption, namely plasma carotene (r = 0.64) and fecal fat excretion (r = 0.76). Our data therefore indicate that the abnormality in linoleate is associated with (secondary to) malabsorption of dietary fat despite pancreatic enzyme replacement therapy and consumption of a regular diet. The frequency of this alteration was determined to be quite high in 40 patients with steatorrhea, 85% of whom showed values below the lower limit of normal for plasma linoleate. It was of interest to find markedly decreased levels of linoleate in adipose tissue, cardiac muscle, and lung and lesser reductions in liver and psoas muscle taken at autopsies. Tissue arachidonic acid percentage was normal, however, and 20:3?>9 was rarely present. Thus, the physiological significance of this common abnormality in CF patients with malabsorption remains to be determined.

Cystic Fibrosis Newborn Screening: Impact on Reproductive Behavior and Implications for Genetic Counseling

Objective. To evaluate the impact of newborn screening for cystic fibrosis (CF) on the reproductive knowledge and behavior of CF families and to determine if heterozygote detection with the immunoreactive trypsinogen (IRT) method in conjunction with DNA analysis (IRT/DNA) influences knowledge and attitudes about reproduction in false-positive families. Methods. The Wisconsin CF Neonatal Screening Project investigated 650 340 infants from 1985 to 1994 in a comprehensive randomized controlled trial to study both benefits and risks of newborn screening and to determine if early diagnosis would improve the prognosis of children with CF. Assessments of reproductive knowledge, attitudes, and behaviors of 135 families of children diagnosed as having CF in both the early treatment group and control groups were made 3 months after diagnosis using a questionnaire which was completed by 100 families. The same questionnaire was administered 1 year later to evaluate retention of information. It was completed by 71 families. A follow-up assessment tool was also administered in 1994 and responses obtained from 73 families. Knowledge, attitudes, and behavior among false-positive families were also assessed at the time of the sweat test in 206 families who experienced IRT screening and 109 families tested with the IRT/DNA method. Follow-up assessments were completed 1 year later in 106 IRT families and 63 IRT/DNA families. Results. In families with a CF child, 95% initially understood that there was a 1 in 4 risk in subsequent pregnancies, and there was good retention of this information 1 year later. At the 1994 assessment, 52% of families had not yet conceived more children, but 74% of these already had children. In the couples in whom CF was diagnosed in the first child, 70% (95% confidence interval = 54% to 85%) conceived more children. There were 43 subsequent pregnancies in 31 families. Prenatal diagnosis was used by 26% of the families (8/31) for 21% of the pregnancies (9/43). There were 3 pregnancies with CF detected, all of which were carried to term. In the false-positive groups, >95% of families initially understood that their child definitely did not have CF. There was no difference between false-positive IRT and IRT/DNA groups, and the information was retained at 1 year. Follow-up assessment 1 year after negative sweat tests revealed that 7% of the IRT and 10% of the IRT/DNA families still thought about the results often or constantly. When asked whether the experience of screening affected feelings about having more children, an affirmative response was obtained in 4% of IRT families but in 17% of IRT/DNA families. One year later, more than half of the false-positive IRT/DNA families did not understand that they were at increased risk of having a child with CF. Conclusions. We conclude that CF neonatal screening does not have a significant impact on the reproductive behavior of most families and that prenatal diagnosis is not used by the majority of CF families. IRT/DNA testing experiences seem to affect attitudes about having more children, and some parents are confused about the implications of the results, even with genetic counseling. However, persistent concerns about the sweat test result are limited. Questions raised by this study confirm the need for more research regarding the process of genetic counseling and its impact on reproductive attitudes and behavior in the newborn screening setting.

Parents' Knowledge of Neonatal Screening and Response to False-positive Cystic Fibrosis Testing

Neonatal screening for cystic fibrosis (CF) has become feasible through analyzing dried blood specimens for immunoreactive trypsinogen (IRT), but the benefits and risks of such a screening program remain to be delineated. This study, a survey of the parents of 104 Wisconsin infants with false-positive IRT tests, showed parents had knowledge deficits about neonatal screening in general, misconceptions about test results, and high levels of anxiety. Parenting behaviors were reportedly unchanged during the usual 3-day waiting period between the news of the abnormal screeing test and the diagnostic sweat test. Most, but not all, parents were relieved by negative sweat test results subsequent to the abnormal IRT test. Factors associated with continued parental concern included having less than a high school education and/or having an infant with low Apgar scores. Additionally, those contacted by telephone were more likely to have misinformation and lingering concerns about the presence of CF in their child. J Dev Behav Pediatr 13:181–186, 1992. Index terms: cystic fibrosis, neonatal screening, trypsinogen, anxiety.

Correction of Linoleic Acid Deficiency in Cystic Fibrosis

ABSTRACT. To identify evidence of essential fatty acid deficiency, we screened 64 patients with cystic fibrosis by analyzing total lipid extracts from plasma. Forty-three had an abnormal linoleate (18:2) level (less than 26%). Thirteen deficient patients (aged 10-24 yr) ingested for 1 yr 7% of their total calories as linoleate derived from a daily supplement of Microlipid. Five deficient patients (aged 10-37 yr) served as controls. Plasma and erythrocyte fatty acid composition were monitored by gas chromatography of total lipid extracts seven times during the twelve month period. Prostaglandins E2 and F2α and their 15 keto 13, 14 dihydrometabolite, 6-keto F1α, and thromboxane B2 were measured by radioimmunoassay. Sweat tests, oxygen saturation, growth indices, clinical severity scores, compliance, and possible side effects from taking Microlipid were followed. Results showed that oral supplementation with Microlipid can significantly increase plasma and erythrocytes %18:2. One compliant patient died during the study and had normal tissue 18:2 levels. Nine of 13 patients gained more weight while taking Microlipid than in the previous year. No significant changes in sweat electrolytes, clinical scores, or oxygen saturation were found during the study year. Prostaglandin metabolites prostaglandin E2 showed an upward trend in supplemented patients, compared to controls. Prostaglandin F2α remained unchanged over 1 yr but showed a trend significantly downward over the final 6 months in supplemented patients. We conclude that linoleate deficiency can be corrected with daily Microlipid supplements and that correction may alter prostaglandin metabolism

Temporal Associations Among Energy Intake, Plasma Linoleic Acid, and Growth Improvement in Response to Treatment Initiation After Diagnosis of Cystic Fibrosis

OBJECTIVE. It is unclear why some patients with cystic fibrosis (CF) succeed (“responders”) in recovering from malnutrition and growth faltering after treatment initiation whereas others fail to do so (“nonresponders”). We conducted a study to test the hypothesis that sustained high energy intake (↑EN) and normal plasma essential fatty acid status are critical determinants of treatment responsiveness within 2 years after diagnosis of CF. METHODS. A total of 71 CF children who had pancreatic insufficiency but not meconium ileus and were enrolled in the Wisconsin CF Neonatal Screening Project were studied. Responders were defined by having achieved adequate weight gain, as indicated by a recovery of weight z score (Wtz) comparable to Wtz at birth (WtzBR) within 2 years of diagnosis. ↑EN and sustained normal plasma linoleic acid level (↑pLA) were defined by achieving energy intake ≥120% of estimated requirement for ≥75% of the time and maintaining plasma LA ≥26% of total fatty acids for ≥75% of the time, respectively. RESULTS. Thirty-two (68%) screened patients and 13 (54%) patients whose CF was diagnosed conventionally recovered WtzBR within 2 years of diagnosis. Screened patients responded at significantly younger ages (mean/median: 6.3/4.3 months) than patients whose CF was diagnosed conventionally (mean/median: 15.8/11.8 months). Proportionately fewer screened patients (33%) achieved ↑EN compared with patients whose CF was diagnosed conventionally (73%). However, more screened patients responded to ↑EN and recovered WtzBR (91%) than patients whose CF was diagnosed conventionally (56%), although this difference was of borderline significance. Compared with having neither ↑EN nor ↑pLA, the likelihood of being a responder was greatest with combined ↑EN and ↑pLA, followed by ↑EN only. The positive associations between ↑EN and ↑pLA to treatment responsiveness remained significant after adjustment for neonatal screening status, baseline height and weight status, and indices of pulmonary disease severity. CONCLUSION. ↑EN and ↑pLA are critical in promoting adequate weight gain in children with newly diagnosed CF.

Oral Supplementation with a High-Fat, High-Energy Product Improves Nutritional Status and Alters Serum Lipids in Patients with Cystic Fibrosis

OBJECTIVE To assess the tolerance and acceptability of a nutrition supplement in patients with cystic fibrosis (CF), to monitor changes in dietary intake, and to evaluate nutritional status. DESIGN Subjects were their own controls for this 3-month, prospective, open study. Acceptability and tolerance questionnaires and 3-day food records were completed at baseline and monthly intervals. Compliance and nutritional status were also assessed. SETTING This study was conducted at the University of Wisconsin Hospital and Clinics Cystic Fibrosis Center, Madison. SUBJECTS Patients with CF older than 4 years of age were recruited during clinic or hospital visits if they met specific weight or growth criteria (n = 19). INTERVENTION Subjects were asked to consume the supplement at a maximum of 30% their estimated daily energy requirements. MAIN OUTCOME MEASURES Responses to acceptability ratings of and tolerance questions about the supplement were obtained along with anthropometric data and biochemical measurements of serum albumin, plasma retinol, alpha-tocopherol, and fatty acid levels. STATISTICAL ANALYSES PERFORMED Data were analyzed using Minitab and Statistical Analysis Software. Paired and unpaired t tests and nonparametric sign tests were used, as well as regression and Pearson correlations. A significance level of .05 was used for all tests. RESULTS All subjects tolerated the supplement, although 12 reported mild symptoms of fullness, nausea, and/or bloating, which were resolved when intake was distributed throughout the day. Mean compliance was 69% of recommended intake. Weight gain in children was strongly correlated with compliance (r = .98). Linoleic acid intake increased significantly (P = .0003) as did plasma linoleic acid in the phospholipid fraction (P = .03). CONCLUSION The supplement studied would be a beneficial addition to the supplementation choices available to patients with CF.

Comparison of the structure and aspects of the proteinase-binding properties of cystic fibrotic alpha-macroglobulin with normal alpha 2-macroglobulin.

Summary: Considerable attention has been focused recently on α2-macro-globulin (α2M), a major endopeptidase inhibitor in blood plasma, as a possible source of the primary defect in cystic fibrosis (CF). We report here studies designed to compare the structure of CF α2M with normal α2M to determine if there is a difference. The physicochemical properties of purified α2M as revealed by various electrophoretic techniques, covalent proteinase binding properties, and primary structural studies on a variety of partial hydrolyzates of CF α2M and normal α2M are compared. These studies were carried out on eight different individual isolates of CF α2M and three age-matched normal α2M preparations and α2M isolated from fetal cord blood. Three properties of CF α2M were studied by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE): (1) the existence of four identically-sized subunits in the native molecule (10), (2) the cleavage of this subunit into fragments of approximately 100,000 daltons upon interaction with proteinases (10), and (3) the cleavage of an alkaline/heat sensitive bond to produce 120,000 and 60,000 dalton fragments (11). Both CF and normal α2M were cleaved to the extent of 79–87%. CF α2M behaves identically with normal α2M with regard to all these properties. Salvesen and Barrett (24) have demonstrated that varying proportions of several [125I]-labeled proteinases form SDS-stable, non-reducible links to normal α2M. Two of the CF α2M preparations were studied to determine if similar covalent binding of proteinases occurred. The positions of the labeled and % of proteinase bound bands in SDS/reduced PAGE system were identical for normal α2M and CF α2M. These results indicate that CF α2M behaves normally with regard to covalent binding of proteinases. Qualitative comparison of the peptide fragments separated by SDS-PAGE or isoelectric focusing of CF and normal α2M produced by partial proteolysis with trypsin, chymotrypsin or Staphylococcus aureus V-8 proteinase did not reveal any differences unique to CF α2M. The cyanogen bromide fragmentation studies and the cysteine cleavage studies also indicated that no major change in the positions of methionyl residues or cysteinyl/cystinyl residues has occurred in CF α2M. The failure of all these different studies and those reported by others to demonstrate any differences between CF and normal α2M makes it highly unlikely that there is a primary defect in α2M in CF.Speculation: The abnormalities previously reported that are associated with α2-macroglobulin-proteinase complexes in cystic fibrosis do not arise from a primary defect in the structure of α2-macroglobulin.

790 CEPHALEXIN IN CYSTIC FIBROSIS: A PLACEBO-CONTROLLED STUDY

The efficacy of cephalexin monohydrate 50 mg/kg/d was evaluated in a placebo-controlled, double-blind, crossover study of patients with cystic fibrosis. Over a 2 year period, 17 patients with mild-moderate disease were treated for 4 month intervals with either cephalexin or placebo. One patient developed drug-related vulvovaginitis and dropped-out of the study. Although colonization by cephalexin-resistant S. aureus was not observed, 2 patients had an increase in sputum concentration of Ps. aeruginosa during antibiotic therapy.Patients previously colonized with ≥ 106 CFU/ml Ps. aeruginosa of H. influenzae had no alteration in flora. Six of 8 patients colonized with ≥ 106 CFU/ml S. aureus had a decrease in S. aureus concentration to < 104 CFU/ml during treatment with cephalexin. During periods of drug treatment, significantly reduced S. aureus colonization (7% versus 26% of cultures), increased weight gain (1.2 versus 0.2 kg/4 months) and less hospitalizations (2 versus 15) were observed (P < 0.01). There were no differences in pulmonary function tests, chest x-rays, or sputum production during periods of antibiotic or placebo treatment.Cephalexin, when compared to placebo, altered the microbial flora and clinical course of some patients with cystic fibrosis.