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Biomedical subjects

P M Farrell

Publications and source records attributed to P M Farrell.

At least 55 records · Page 3Linked to original sources
PubMed1995

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.

Adolescent↗
PubMed1994

Severe hemolytic anemia associated with vitamin E deficiency in infants with cystic fibrosis. Implications for neonatal screening.

Three infants are described with cystic fibrosis (CF) and malnutrition leading to severe anemia beginning as early as 6 weeks of age. Laboratory studies demonstrated high reticulocyte counts, negative Coombs' tests, abnormal peroxide hemolysis test results, and biochemical evidence of vitamin E deficiency. Oral administration of alpha-tocopherol resulted in rapid correction of the in vitro hemolysis and improvement of in vivo hematologic indices. Investigation of these patients supports the conclusion that the hemolytic anemia of infancy in CF is caused by vitamin E deficiency and should be treated promptly with 50 IU/day of vitamin E. Because two of the three patients were identified in a CF screening/surveillance program, we can estimate that the frequency of clinically significant anemia in CF infants is 4%. Our observations demonstrate a potential advantage of CF neonatal screening for individual patients susceptible to vitamin E-deficient hemolytic anemia and suggest that confirmatory follow-up diagnostic studies, such as sweat tests, should be performed by 4 to 6 weeks of age.

Anemia, Hemolytic↗
PubMed1994

Newborn screening for cystic fibrosis in Wisconsin: first application of population-based molecular genetics testing.

Infants born in Wisconsin are being screened for cystic fibrosis (CF) associated with the F508 mutation. This screening program has been developed during 9 years of research supported by the National Institutes of Health and involves a unique, two-tier system employing measurement of immunoreactive trypsinogen (IRT) initially. When the IRT level is high, DNA is extracted from the neonatal dried blood specimen and analyzed for the F508 mutant allele, following polymerase chain reaction (PCR) amplification; the F508 mutation is present in more than 90% of CF patients and accounts for the common, severe form of the disease. Infants with a positive DNA test are either CF heterozygote carriers or CF patients, depending on the results of a sweat test, which should be performed at 4 weeks of age. Screening the newborn population for CF provides the opportunity for early nutritional and respiratory interventions, as well as genetic counseling. This represents the first population-based application of molecular genetics for detection of a major congenital disorder causing serious public health problems. The process by which the recommendation was reached to screen for CF is described in this article, along with new information on the pathogenesis of CF, its clinical presentation, the rationale for newborn screening, and the method developed for the screening program.

Cystic Fibrosis↗
PubMed1993

Application of DNA analysis in a population-screening program for neonatal diagnosis of cystic fibrosis (CF): comparison of screening protocols.

We compare two protocols for newborn screening for cystic fibrosis (CF). The first uses the immunoreactive trypsinogen (IRT) assay with a cutoff of > or = 180 ng/ml and a sweat test to identify CF patients. The second uses the IRT assay with a 100 ng/ml cutoff in conjunction with direct analysis for the delta F508 CF transmembrane conductance regulator (CFTR) mutation in a two-tiered (i.e., IRT/DNA) protocol, followed by a sweat test. We screened 220,865 newborns from Wisconsin for CF, using the IRT protocol identifying 369 infants with an elevated IRT, of whom 46 were found to have CF. Another 7 CF patients were identified who had a false-negative IRT level. The CF incidence in the white population was 1 in 3,431 (carrier incidence of 1 in 30). The IRT protocol had a sensitivity of 87% and a positive predictive value of 12.5%. We subsequently used the IRT/DNA protocol to screen 21,258 infants. Of 518 infants with an IRT level > or = 100 ng/ml, 24 carried at least one copy of the delta F508 CFTR mutation, and 4 of these infants were found to have CF, yielding a positive predictive value for this protocol of 16.7%. Direct comparison of the positive predictive value of the two protocols is not valid, because of the different populations screened. However, had the IRT protocol been used on the IRT/DNA cohort, 50 infants, including the 4 with CF, would have received sweat tests, yielding a positive predictive value of 8%. Because of the small sample size, this positive predictive value is not significantly different from that obtained for the IRT/DNA test. However, from a practical point of view the IRT/DNA approach does decrease considerably the number of sweat tests that must be undertaken. The number of false positives for the IRT protocol (46 in 21,258) is increased significantly compared with that for the IRT/DNA approach (20 in 21,258; P < .001). The incidence of delta F508 carriers detected in cohorts with an elevated IRT level was increased compared with the incidence in the general population. The direct costs for the IRT/DNA approach (100 ng/ml) were $11,374 per CF patient detected, compared with $10,187 per CF patient detected for the IRT protocol. Therefore, we conclude that the IRT/DNA approach to CF newborn screening decreases the number of false-positive subjects contacted, without a significant increase in cost.

Analysis of Variance↗
PubMed1993

Wisconsin cystic fibrosis chest radiograph scoring system.

A new clinical scoring system for patients with cystic fibrosis is needed because of recent advances in diagnosis and treatment which have changed the course of this disease. Chest radiograph scoring is the best objective measure of pulmonary disease for longitudinal studies beginning with infants; however, based on pilot studies, previous scoring systems are not sensitive enough in discriminating between degrees of mild lung disease. Therefore, a new radiographic scoring system was developed with the goal of achieving both sensitivity and reproducibility. This objective was pursued by applying multiattribute utility theory, using a panel of interpreters with expertise in cystic fibrosis radiology, and employing mathematical modeling techniques to weight the various components. The system was developed and validated in three phases including comparison to the Brasfield method of quantitative radiology. The data demonstrate that the new system can be applied reliably and conveniently to generate reproducible scores of pulmonary disease severity. Evaluation of the scores by four independent raters using chest radiographs from 61 patients at an average age of 8.37 years revealed good agreement with a .714 Kendall coefficient of concordance. Assessment of serial changes over time was performed using a group of 176 chest radiographs from 25 patients ranging from 4 weeks to 6 years old; this showed that the Wisconsin system generates score differences that are greater in magnitude with disease progression compared with the Brasfield method. Therefore, the new method is more sensitive to progression of mild disease and should be superior to prior radiographic scoring systems for evaluating therapies designed to modify the early course of disease. The Wisconsin system is designed to be useful in longitudinal clinical studies involving young children with cystic fibrosis and is capable to detecting progression from normality to mild lung disease.

Adolescent↗
PubMed1992

Nutritional assessment and management in cystic fibrosis: a consensus report. The Consensus Committee.

This report is a summary of a meeting convened by the Cystic Fibrosis Foundation to develop a consensus among nutrition specialists and cystic fibrosis care givers regarding optimal nutritional management of patients with cystic fibrosis. The first section of the report provides a rationale for emphasizing nutritional management of this genetic disorder. The multiple factors causing malnutrition and a negative energy balance are outlined. The second section provides guidelines for routine assessment of nutrition in these patients. Five categories of nutritional status are defined based on ideal weight for height, age, and gender. These categories are used to formulate a graded response for nutritional intervention. Recommendations are provided for routine dietary supplements, vitamin supplements, and pancreatic enzyme replacement. The primary aim of this report is to educate clinicians as to the importance of frequent assessments and early intervention.

Cystic Fibrosis↗
PubMed1992

Newborn screening for cystic fibrosis. The Cystic Fibrosis Neonatal Screening Study Group.

Many questions remain regarding the efficacy, risks, and costs of CF neonatal screening. The major gap in knowledge that must be closed before CF neonatal screening can be recommended generally in the United States concerns the potential long-term medical benefits of initiating treatment in early infancy. It would be premature, in our opinion, to implement mass population screening of newborns for CF until the benefits and risks have been fully defined, and an adequate and logistically feasible testing system developed and/or highly effective therapy for CF lung disease becomes available. It is for this reason we designed a randomized, controlled investigation of CF neonatal screening and implemented this project in Wisconsin during 1985. The fact that 5 years of randomized screening and systematic evaluation of outcome measures have not yet revealed any pulmonary benefits underscores the importance of rigorous investigation to resolve the efficacy issue. In addition to the medical uncertainties, we believe that the ethical issues described herein need to be resolved; this concern pertains not only to the CF patient but also the heterozygote carrier. On the other hand, financial factors and uncertainty about the cost effectiveness of CF neonatal screening do not appear to be dominant issues according to our assessment of current data. Despite the reservations related to the benefit/risk relationship, we expect that the discovery of the CF gene should have a favorable impact on neonatal screening for the disease, as well as for management.

Cost-Benefit Analysis↗
PubMed1992

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 screening 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.

Anxiety↗
PubMed1991

Current issues in neonatal screening for cystic fibrosis and implications of the CF gene discovery.

Many questions remain regarding the efficacy, toxicity, and costs of CF neonatal screening. It would be premature, in our opinion, to implement mass population screening of newborns for CF until the benefits and risks have been fully defined, and an adequate and logistically feasible testing system developed and/or highly effective therapy for CF lung disease becomes available. In addition, the ethical issues described herein need to be resolved. This pertains not only to the CF patient but also the heterozygote carrier. These reservations notwithstanding, the discovery of the CF gene should have a favorable impact both directly and indirectly on neonatal screening for the disease. Mutation analysis coupled to IRT testing seems most attractive at this time, at least on a research basis, but primary molecular diagnostic procedures might supervene in the future, particularly if they are financially feasible.

Chromosome Mapping↗
PubMed1991

Nutritional assessment of infants with cystic fibrosis diagnosed through screening.

Presymptomatic infants diagnosed through neonatal screening for cystic fibrosis can have biochemical evidence of malnutrition. With aggressive dietary management and treatment with pancreatic enzymes, normal biochemical indices of nutrition can be achieved at 12 months of life in most cases. Males with cystic fibrosis appear to be more at risk than females for abnormal growth and biochemical indices of nutrition in the first year of life. This may be related to the observed decrease in fat intake when compared to females. Males, especially, should be carefully observed for development of nutritional abnormalities based on this data. Careful attention should be paid to vitamin E and essential fatty acid status in all CF infants. The numbers in this study are small and the long-term consequences of early nutritional intervention await the conclusion of the randomized, controlled study on-going in Wisconsin.

Cystic Fibrosis↗
PubMed1991

Laboratory quality control issues related to screening newborns for cystic fibrosis using immunoreactive trypsin.

We have incorporated the IRT assay for CF to our newborn screening program, relying heavily on electronic data processing to optimize the test results in order to provide the most reliable data possible from the specimen at hand. We have established an internal cut-off of 100 ng/mL and an external referral of 180 ng/mL; this virtually eliminates the possibility that analytical imprecision will result in misidentifying a positive patient specimen. The relationship between IRT levels and various mutant forms of CF are not well established, and it is possible that various forms of CF may exhibit different levels of IRT in the first few days of life. We believe that IRT screening for CF could be a useful procedure for early identification of potential CF. However, by comparison with other newborn screening tests, its sensitivity, 90%, presents a concern. The expectation for PKU, hypothyroidism, MSUD, and galactosemia screening is 100% sensitivity. A false-negative usually results in litigation. The use of IRT in routine newborn screening will require considerable education of the general public and physicians receiving test results. Our program, along with many others, is anxiously watching the developments in the area of gene testing. We feel the relatively inexpensive IRT, used for mass screening can be successfully coupled with the more definitive (and expensive) gene test on a selected population to identify CF at the earliest possible age in a more effective manner. It is possible that in the near future gene probe tests will be applied in a cost effective manner to the initial filter paper specimen.

Cystic Fibrosis↗
PubMed1991

Nutritional status of infants with cystic fibrosis associated with early diagnosis and intervention.

The purpose of this study was to characterize the nutritional status of infants diagnosed with cystic fibrosis (CF) through neonatal screening and to determine if they would achieve normal nutrition when managed with early intervention. In addition, nutrient intake was assessed to determine energy and macronutrient-consumption patterns. Evaluation of growth revealed that normal patterns could be achieved with mean energy intake values at ages 6 and 12 mo of 481 and 426 kJ/kg body wt (115 and 102 kcal/kg body wt), respectively. Biochemical assessment demonstrated low alpha-tocopherol and linoleic acid values at diagnosis in the majority of infants whereas one-third had abnormal indices of protein nutriture. Essential fatty acid deficiency was also demonstrated at diagnosis by abnormal triene-tetraene ratio values in 27% of screened infants. With predigested formula and dietary supplementation, there was improvement in all indices of nutritional status and only a low percentage of patients showed mild biochemical abnormalities at age 12 mo.

Anthropometry↗
PubMed1991

Intravenous infusion of lipid for the prevention of essential fatty acid deficiency in premature infants.

This study was designed to determine the amount of linoleic acid required to prevent essential fatty acid deficiency in premature infants. This was achieved by infusing 1 g intravenous lipid.kg-1.d-1 over 18-20 h beginning on day 2 and increasing by 0.5 g.kg-1.d-1 to a maximum of 3 g.kg-1.d-1. The actual mean amounts of linoleic acid administered (mg/kg) were 613 on day 2, 767 on days 3 and 4, 862 on day 5, and 1062 on day 6. None of the neonates managed in this fashion showed a high triene-tetraene ratio on days 3 or 7 (in contrast to control subjects, 80% whom were abnormal). Plasma triglycerides and nonesterified fatty acids (NEFAs) increased during the infusions but not to concentrations indicative of fat intolerance. The rise in NEFAs was associated with evidence of bilirubin displacement from circulating albumin but this occurred to only a modest degree.

Bilirubin↗
PubMed1990

Relationships among surfactant fraction lipids, proteins and biophysical properties in the developing rat lung.

Lung development is associated with increases in specific phospholipids and proteins that function as critical pulmonary surfactant components. Attempts to characterize the pattern of surfactant development in fetal rat lungs have been hampered by the lack of a micromethod which will permit quantitative isolation of surface active components from small tissue specimens. As part of studies designed to elucidate the metabolic regulation of lung development in the rat, we developed sucrose density gradient centrifugation procedures to separate pulmonary phospholipids and proteins into a presumed surfactant (S) fraction and a residual (R) fraction. Electron microscopy of S pellets from mature fetuses identified predominant lamellar bodies and minimal contamination; incubation with 5 mM CaCl2 induced the appearance of tubular myelin figures, implying functional potential. This was confirmed by demonstrating low surface tension (less than 1 dyn/cm) in S, but not R, fractions at term gestation (21.5 days) and in 1-day-old neonatal lung isolates, based on dynamic measurements using the oscillating bubble technique. Surface activity was also high in the S pellets from fetuses at 20.5 days of gestation; however, at 19.5 days, minimum surface tension values of at least 19 dyne/cm were seen. These results correlated directly with biochemical analyses which indicated striking increases in three surfactant-associated proteins (SP-A, SP-B, and SP-C) after 19.5 days of gestation; a finding in agreement with previously reported data on the developmental increase of disaturated phosphatidylcholine in fetal rat lung. We conclude that isolation of S fraction components is valuable for demonstrating maturation of the fetal rat lung and may provide a useful tool for the study of regulatory mechanisms influencing surfactant production and function.

Animals↗
PubMed1990

Brain damage induced by prenatal exposure to dexamethasone in fetal rhesus macaques. I. Hippocampus.

Neurotoxic effects of prenatal administration of dexamethasone were examined in the fetal rhesus monkey brain at 135 and 162 days of gestation (term is 165 days). In an experimental design mimicking human clinical trials, dexamethasone was given intramuscularly to pregnant monkeys on day 132 (single injection with doses of 0.5, 5, or 10 mg/kg maternal body weight) or on days 132 and 133 (multiple injections at 12-h intervals with 0.125 x 4, 1.25 x 4, or 2.5 mg/kg x 4). The fetuses were delivered by caesarean section on day 135 or day 162 and hippocampal slices were prepared for evaluation. Light and electron microscopic observation revealed decreased numbers of pyramidal neurons in the hippocampal CA regions and of granular neurons in the dentate gyrus associated with degeneration of neuronal perikarya and dendrites. Axodendritic synaptic terminals of the mossy fibers in the CA3 hippocampal region showed pronounced degeneration. Degeneration was dose-dependent and multiple injections induced more severe damage than single injections of the same total dose. Even the lowest dose (0.5 mg/kg, which is similar to the dose used in human clinical trials) produced these changes. Degenerative changes induced by dexamethasone treatment (5 mg/kg) on days 132 and 133 were also clearly evident in fetuses studied at 162 days. Therefore, caution is recommended in the use of prenatal corticosteroids in premature deliveries.

Animals↗
PubMed1990

Newborn screening for cystic fibrosis is complicated by age-related decline in immunoreactive trypsinogen levels.

Detection of elevated levels of immunoreactive trypsinogen (IRT) in dried neonatal blood spots has been used as a screening test for cystic fibrosis. In other cystic fibrosis newborn-screening studies, a sweat chloride test is generally performed only if an infant has a persistent IRT level above a selected cutoff value on both the initial and subsequent specimens. Neither the timing of the second specimen nor the value of the cutoff point for the second specimen has been comprehensively evaluated. In this randomized, controlled study, 145,024 infants were screened in the neonatal period for cystic fibrosis using the 99.8 percentile (180 ng/mL) as the neonatal cutoff point. A total of 129 infants had elevated neonatal IRT levels and had negative results on sweat tests (false-positive by IRT screening). A total of 54 children with cystic fibrosis were identified in the screened and comparison groups. Excluding patients with meconium ileus, 4 infants with cystic fibrosis had neonatal IRT values less than 180 ng/mL, and an additional 9 infants with cystic fibrosis had values decline to less than 180 ng/mL within the first 2 1/2 months of age. The IRT values of infants with and without cystic fibrosis overlapped considerably beyond 30 days of age. These findings suggest that further refinement of cystic fibrosis screening methodology will be necessary to achieve an acceptable sensitivity and specificity.

Aging↗
PubMed1989

Immunoreactive trypsinogen screening for cystic fibrosis: characterization of infants with a false-positive screening test.

Blood immunoreactive trypsinogen (IRT) is elevated in newborns with cystic fibrosis (CF) and has been used as a neonatal screening test. However, not only is the benefit of early diagnosis unknown, but also the sensitivity, specificity, and time related decline of IRT values have yet to be comprehensively evaluated. This report describes the characteristics of infants with a false-positive IRT in our experience with CF screening of 87,000 infants. The IRT value was elevated in 92 newborns; 13 had a confirmed diagnosis of CF by quantitative pilocarpine iontophoresis sweat testing, and 79 infants did not have CF and were therefore classified as false positives by IRT screening. In order to test the hypothesis that perinatal stress factors are associated with high neonatal IRT values, we evaluated Apgar scores at 1 and 5 minutes. We found that the scores of false-positive infants were significantly lower (P = 0.0004 and P = 0.0102 at 1 and 5 minutes, respectively), compared with infants in the general population. While perinatal asphyxia as reflected by low Apgar scores is an associated factor accounting for an elevated IRT value, the majority of non-CF newborns with an elevated IRT have normal Apgar scores.

Apgar Score↗