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Biomedical subjects

M Corey

Publications and source records attributed to M Corey.

At least 19 recordsLinked to original sources
PubMed2005

Sex differences in habitual physical activity and lung function decline in children with cystic fibrosis.

OBJECTIVES: To evaluate the feasibility of measuring habitual physical activity (HPA) in children with cystic fibrosis (CF) and to assess the relation between HPA and the rate of decline in FEV1 over a period of 2 years. STUDY DESIGN: At regular clinic visits, 109 patients (7 to 17 years; 56 girls) performed pulmonary function testing and completed the Habitual Activity Estimation Scale (HAES). Patients were divided into quartiles, based on activity levels derived from the HAES. RESULTS: Girls in the two lowest activity quartiles had a more rapid rate of decline FEV1 (-3.40% and -3.05% predicted, respectively) than girls in the two highest activity quartiles (-0.93% and +1.17% predicted, respectively) (P = .02). In boys, the rate of decline of FEV1 was similar in all activity quartiles (-1.95% predicted). Patients reported significantly more activity in summer compared with spring, winter, and fall (P < .0001), and boys reported greater activity than girls (6.5 +/- 2.9 vs 5.4 +/- 2.5 h/d, P < .05). CONCLUSIONS: The annual rate of change of FEV1 was related to activity quartile in girls but not in boys. This research suggests that an inactive lifestyle may partially explain the poorer survival of female patients with CF. The HAES is a feasible tool for routine follow-up of HPA in our CF clinic.

Adolescent↗
PubMed2005

The prevalence and clinical characteristics of cystic fibrosis in South Asian Canadian immigrants.

BACKGROUND: Cystic fibrosis (CF) is considered to be rare among individuals from the Indian subcontinent. Furthermore, affected individuals are reported to experience a more severe clinical course. AIMS: It was hypothesised that CF is under diagnosed in people of South Asian origin and therefore the prevalence may be higher than previously estimated. METHODS: The prevalence of CF in the South Asian and in the general population living in the same geographic region (Metropolitan Toronto) were compared between 1996 and 2001. Population data were obtained from the Canadian census survey. CF phenotype and genotype data were obtained from the Toronto CF database. RESULTS: Among 381 patients with CF, 15 were of South Asian descent. The age related prevalence of CF among the South Asian and general populations was: 0-14 years, 1:9200 versus 1:6600; 15-24 years, 1:13,200 versus 1:7600; older than 25 years, 1:56,600 versus 1:12,400. Age at diagnosis, duration and severity of symptoms at diagnosis, current nutritional status, and FEV(1) were similar in the two groups. While not significant, FEV1 tended to be lower (48% versus 57% predicted) among adult South Asians, compared to the general CF population. Also, the percentage with pancreatic sufficiency was higher (27% versus 16%) and the frequency of DeltaF508 allele was lower (50% versus 65.1%). CONCLUSIONS: These data suggest that the prevalence and natural history of CF in South Asians is similar to that among individuals of European origin. The relatively lower prevalence among older South Asians may reflect an improving recognition of CF in this ethnic subgroup.

Adolescent↗
PubMed2003

Molecular consequences of cystic fibrosis transmembrane regulator (CFTR) gene mutations in the exocrine pancreas.

BACKGROUND AND AIMS: We tested the hypothesis that the actual or predicted consequences of mutations in the cystic fibrosis transmembrane regulator gene correlate with the pancreatic phenotype and with measures of quantitative exocrine pancreatic function. METHODS: We assessed 742 patients with cystic fibrosis for whom genotype and clinical data were available. At diagnosis, 610 were pancreatic insufficient, 110 were pancreatic sufficient, and 22 pancreatic sufficient patients progressed to pancreatic insufficiency after diagnosis. RESULTS: We identified mutations on both alleles in 633 patients (85.3%), on one allele in 95 (12.8%), and on neither allele in 14 (1.9%). Seventy six different mutations were identified. The most common mutation was DeltaF508 (71.3%) followed by G551D (2.9%), G542X (2.3%), 621+1G-->T (1.2%), and W1282X (1.2%). Patients were categorized into five classes according to the predicted functional consequences of each mutation. Over 95% of patients with severe class I, II, and III mutations were pancreatic insufficient or progressed to pancreatic insufficiency. In contrast, patients with mild class IV and V mutations were consistently pancreatic sufficient. In all but four cases each genotype correlated exclusively with the pancreatic phenotype. Quantitative data of acinar and ductular secretion were available in 93 patients. Patients with mutations belonging to classes I, II, and III had greatly reduced acinar and ductular function compared with those with class IV or V mutations. CONCLUSION: The predicted or known functional consequences of specific mutant alleles correlate with the severity of pancreatic disease in cystic fibrosis.

Child↗
PubMed2001

Safety of the Canadian blood supply in 1980-85: using a paediatric cohort for risk assessment of human immunodeficiency virus (HIV) infection.

The risk of HIV from transfusions in Canada in the period 1980-85 was estimated, using the information from a transfused paediatric cohort. Children who were transfused between January 1980 and November 1985 at a tertiary care paediatric hospital were contacted by letter. With this notification, HIV testing for recipients was recommended. HIV testing histories were obtained. The number tested for HIV was estimated from the questionnaire responses and from data matching with the HIV-testing laboratory. Cases of HIV infection were identified through multiple sources. In this cohort, 11,028 children were transfused a mean of 21 units. Of the 10,220 living recipients, the estimated proportion tested for HIV was 86% to 91%. Thirty-one cases of HIV infection were identified, representing 0.28% of the cohort but 0.34% of those expected to have been tested. The estimated HIV incidence per 1,000 units transfused ranged from 0.028 [95% CI 0.0007, 0.155] in 1980 to 0.445 [95% CI 0.2592, 0.712] in 1985. This suggests that the risk of HIV from transfusions in Canada continued to rise until the implementation of HIV testing of donors in November 1985.

AIDS Serodiagnosis↗
PubMed2001

Treatment of vitamin K deficiency in cystic fibrosis: Effectiveness of a daily fat-soluble vitamin combination.

OBJECTIVE: Patients with cystic fibrosis (CF) and pancreatic insufficiency (PI) commonly have vitamin K deficiency, and those with CF-associated liver disease (CFLD) have universal vitamin K deficiency. We evaluated the effectiveness of an oral fat-soluble vitamin combination (ADEKs) to treat patients with vitamin K deficiency. STUDY DESIGN: Patients with PI and CF (mean age, 15 years; range, 0.6 to 46 years) including 6 with advanced CFLD were prospectively enrolled in a study of a fat-soluble vitamin combination taken on a daily basis. None had received vitamin K supplementation for at least 4 months before the study. Fat-soluble vitamin combination supplementation was given for a minimum of 4 months; the mean vitamin K intake was 0.18 mg/d (SD = 0.1, range, 0 to 0.3). The primary outcome was change in plasma PIVKA-II (prothrombin in vitamin K absence). RESULTS: Before supplementation 58 (81%) of 72 patients had abnormal PIVKA-II levels (>2.9 ng/mL). After supplementation 29 (40%) had abnormal PIVKA-II levels (P =.001). All 6 patients with advanced CFLD had abnormal PIVKA-II levels (median, range of 20.8, 5.5 to 55 ng/mL) before treatment, which corrected to normal in 50% (4.1, 2.1 to 65 ng/mL). Four patients, 2 with CFLD, had a prolonged prothrombin time (>13.5 seconds) at both time periods. CONCLUSIONS: An oral fat-soluble vitamin combination with a modest amount of vitamin K can, as a daily supplement, improve the PIVKA-II levels in patients with PI and CF.

Adolescent↗
PubMed2000

A comparison of inhaled fluticasone and oral prednisone for children with severe acute asthma.

BACKGROUND: Inhaled corticosteroids are effective in the treatment of children with asthma. It is uncertain how inhaled corticosteroids compare with oral corticosteroids in the management of severe acute disease. METHODS: We performed a double-blind, randomized trial involving 100 children five years of age or older who had severe acute asthma (indicated by a forced expiratory volume in one second [FEV1] that was less than 60 percent of the predicted value) and in whom the results could be evaluated. All were treated with an aggressive bronchodilator regimen and received one dose of either 2 mg of inhaled fluticasone through a metered-dose inhaler with a spacer or 2 mg of oral prednisone per kilogram of body weight. They were assessed hourly for up to four hours. RESULTS: The mean (+/-SD) base-line FEV1 as a percentage of the predicted value was 46.3+/-12.5 in the fluticasone group (51 subjects) and 43.9+/-9.9 in the prednisone group (49 subjects). The FEV1 increased by a mean of 9.4+/-12.5 percentage points in the fluticasone group and by 18.9+/-9.8 percentage points in the prednisone group four hours after therapy (P< 0.001). None of the children in the prednisone group had a reduction in FEV1 as a percentage of the predicted value from base line to four hours, as compared with 25 percent of those in the fluticasone group (P<0.001). Sixteen (31 percent) of the children treated with fluticasone were hospitalized, as compared with five (10 percent) of those treated with prednisone (P=0.01). CONCLUSIONS: Children with severe acute asthma should be treated with oral prednisone and not with inhaled fluticasone or a similar inhaled corticosteroid.

Administration, Inhalation↗
PubMed2000

Segregation analysis in Shwachman-Diamond syndrome: evidence for recessive inheritance.

Shwachman-Diamond syndrome is a rare disorder of unknown cause. Reports have indicated the occurrence of affected siblings, but formal segregation analysis has not been performed. In families collected for genetic studies, the mean paternal age and mean difference in parental ages were found to be consistent with the general population. We determined estimates of segregation proportion in a cohort of 84 patients with complete sibship data under the assumption of complete ascertainment, using the Li and Mantel estimator, and of single ascertainment with the Davie modification. A third estimate was also computed with the expectation-maximization (EM) algorithm. All three estimates supported an autosomal recessive mode of inheritance, but complete ascertainment was found to be unlikely. Although there are no overt signs of disease in adult carriers (parents), the use of serum trypsinogen levels to indicate exocrine pancreatic dysfunction was evaluated as a potential measure for heterozygote expression. No consistent differences were found in levels between parents and a normal control population. Although genetic heterogeneity cannot be excluded, our results indicate that simulation and genetic analyses of Shwachman-Diamond syndrome should consider a recessive model of inheritance.

Abnormalities, Multiple↗
PubMed2000

A randomized controlled trial of a 3-year home exercise program in cystic fibrosis.

OBJECTIVES: To evaluate the effects of a 3-year home exercise program on pulmonary function and exercise tolerance in mildly to moderately impaired patients with cystic fibrosis (CF) and to assess whether regular aerobic exercise is a realistic treatment option. STUDY DESIGN: Seventy-two patients with CF (7-19 years) were randomly assigned to an exercise group (a minimum of 20 minutes of aerobic exercise, at a heart rate of approximately 150 beats/min, 3 times weekly) or a control group (usual physical activity participation). Pulmonary function, exercise tolerance, clinical status, hospitalizations, and compliance with therapy were monitored during scheduled visits to the hospital's CF clinic. RESULTS: Sixty-five patients were included in the analyses. The control group demonstrated a greater annual decline in percent of predicted forced vital capacity compared with the exercise group (mean slope +/- SD, -2.42 +/- 4.15 vs -0.25 +/- 2.81; P =.02), with a similar trend for forced expiratory volume in 1 second (-3.47 +/- 4.93 vs -1.46 +/- 3. 55; P =.07). Patients remained compliant with the exercise program over the study period. An improved sense of well-being was reported with exercise. CONCLUSIONS: Pulmonary function declined more slowly in the exercise group than in the control group, suggesting a benefit for patients with CF participating in regular aerobic exercise. Consistent compliance with the home exercise program and a self-reported positive attitude toward exercise provide further evidence of the feasibility and value of including an aerobic exercise program in the conventional treatment regimen of patients with CF.

Adolescent↗
PubMed2000

Pregnancy in cystic fibrosis. Fetal and maternal outcome.

OBJECTIVE: To assess the effect of pregnancy on pulmonary function and survival in women with cystic fibrosis (CF) and to assess the fetal outcome. DESIGN: Cohort study. The data analyzed were collected from the Toronto CF database, chart review, and patient questionnaire. SETTING: Tertiary-care center. PATIENTS: All women with CF who, at the time of diagnosis or pregnancy, attended the Toronto Cystic Fibrosis Clinics between 1961 and 1998. RESULTS: From 1963 to 1998, there were 92 pregnancies in 54 women. There were 11 miscarriages and 7 therapeutic abortions. Forty-nine women gave birth to 74 children. The mean follow-up time was 11 +/- 8 years. One patient was lost to follow-up shortly after delivery, and one was lost after 12 years. The overall mortality rate was 19% (9 of 48 patients). Absence of Burkholderia cepacia (p < 0.001), pancreatic sufficiency (p = 0.01), and prepregnancy FEV(1) > 50% predicted (p = 0.03) were associated with better survival rates. When adjusted for the same parameters, pregnancy did not affect survival compared to the entire adult female CF population. The decline in FEV(1) was comparable to that in the total CF population. Three women had diabetes mellitus, and seven developed gestational diabetes. There were six preterm infants and one neonatal death. CF was diagnosed in two children. CONCLUSIONS: The maternal and fetal outcome is good for most women with CF. Risk factors for mortality are similar to those for the nonpregnant CF population. Pregnancies should be planned so that there is opportunity for counseling and optimization of the medical condition. Good communication between the CF team and the obstetrician is important.

Adolescent↗
PubMed1999

Exclusion of linkage of Shwachman-Diamond syndrome to chromosome regions 6q and 12q implicated by a de novo translocation.

Shwachman-Diamond syndrome is a rare genetic disorder of unknown pathogenesis involving exocrine pancreatic insufficiency and hematological and skeletal abnormalities. There is broad clinical variability; the extent of heterogeneity is unknown but comparisons within a large cohort of patients show no striking differences between patients of families with single or multiple affected offspring. Segregation analysis of a cohort of 69 families has suggested an autosomal recessive mode of inheritance. A single constitutional de novo chromosome rearrangement was reported in a Japanese patient involving a balanced translocation, t(6;12)(q16.2;q21.2), thereby suggesting possible loci for a genetic defect. Evenly spaced microsatellite markers spanning 26-32 cM intervals from D6S1056 to D6S304 and D12S375 to D12S346 were analyzed for linkage in members of 13 Shwachman-Diamond syndrome families with two or three affected children. Two-point lod scores were calculated for each marker under assumptions of recessive inheritance and complete penetrance. Negative lod scores indicated exclusion of both chromosome regions. Further, affected sibs were discordant for inheritance of chromosomes in most families based on constructed haplotypes. The cytogenetic abnormality is not associated with most cases of Shwachman-Diamond syndrome.

Bone and Bones↗
PubMed1999

Detecting interactions between gene, site, and environmental variables using GAP.

Regressive models that incorporate measured variables and assumed genetic parameters were used to detect interactions between gene, research site, and environmental variables in GAW11 Problem 2. Replicates 1 to 5 were used in the analyses. Significant three-way gene x environment x site interactions were seen for all models, regardless of what assumptions were made about genetic transmission. Therefore, regressive models within each of the four sites were examined for significant gene x environment interactions. At one site, there was a pattern of gene x environment interaction that was consistent in most of the genetic models assumed. Joint and separate segregation and linkage analyses were compared in this site. No patterns of gene x environment interaction were seen in the other sites. Results from this analysis show that regressive modeling can identify complex interactions in data from heterogeneous populations even when ascertainment assumptions are violated.

Chromosome Mapping↗
PubMed1999

Assessing activity of pediatric Crohn's disease: which index to use?

BACKGROUND & AIMS: The Pediatric Crohn's Disease Activity Index (PCDAI) is a multi-item measure that, in contrast to the adult-derived CDAI, includes linear growth and places less emphasis on subjectively reported symptoms but more on laboratory parameters of intestinal inflammation. This study compared the feasibility, validity, and responsiveness of PCDAI vs. CDAI in the assessment of Crohn's disease activity among pediatric patients. METHODS: Eighty-one children and adolescents with Crohn's disease were studied. A gastroenterologist provided a categorical global assessment of disease activity as quiescent, mild, moderate, or severe after interview and physical examination. CDAI and PCDAI scores were calculated by an independent appraiser. RESULTS: Mean values within each category for CDAI and PCDAI differed significantly between strata. PCDAI values were quiescent, 6.8 +/- 6. 6; mild, 18.7 +/- 7.3; moderate, 38.5 +/- 12.9; and severe, 54.2 +/- 14.0. CDAI values were quiescent, 23.5 +/- 53.6; mild, 96.0 +/- 60. 7; moderate, 184.5 +/- 97.0; and severe, 284.4 +/- 85.8. Individual scores showed less overlap between strata for PCDAI than for CDAI. PCDAI showed better correlation with serum orosomucoid and platelet count, laboratory parameters of inflammation not included in either index. CONCLUSIONS: Both PCDAI and CDAI reflect disease activity in pediatric Crohn's disease. PCDAI is better at discriminating between levels of disease activity.

Adolescent↗
PubMed1999

Shwachman syndrome: phenotypic manifestations of sibling sets and isolated cases in a large patient cohort are similar.

OBJECTIVES: With the use of clinical data from a large international cohort, we evaluated and compared affected siblings and isolated cases. STUDY DESIGN: Data from 116 families were collected, and patients conforming to our predetermined diagnostic criteria were analyzed. Phenotypic manifestations of affected siblings and singletons were compared with the use of t tests, Wilcoxon scores, and chi2 analysis. RESULTS: Eighty-eight patients (33 female, 55 male; median age 5.20 years) fulfilled our predetermined diagnostic criteria for Shwachman syndrome; 63 patients were isolated cases, and 25 affected siblings were from 12 multiplex families. Steatorrhea was present in 86% (57 of 66), and 91% (78 of 86) displayed a low serum trypsinogen concentration. Patients older than 4 years more often had pancreatic sufficiency. Neutropenia occurred in 98%, anemia in 42%, and thrombocytopenia in 34%. Myelodysplasia or cytogenetic abnormalities were reported in 7 patients. Short stature with normal nutritional status was a prominent feature. CONCLUSIONS: Clinical features among patients with Shwachman syndrome varied between patients and with age. Similarities in phenotype between isolated cases and affected sibling sets support the hypothesis that Shwachman syndrome is a single disease entity.

Bacterial Infections↗
PubMed1999

A randomized trial of 72- versus 24-hour intravenous tubing set changes in newborns receiving lipid therapy.

OBJECTIVE: To compare the microbial contamination rate of infusate in the intravenous tubing of newborns receiving lipid therapy, replacing the intravenous delivery system at 72-hour versus 24-hour intervals. DESIGN: Infants requiring intravenous lipid therapy were randomly assigned to have intravenous sets changed on a 72- or a 24-hour schedule, in a 3:1 ratio, in order to compare the infusate contamination rates in an equivalent number of tubing sets. SETTING: A 35-bed, teaching, referral, neonatal intensive-care unit (NICU). PARTICIPANTS: All neonates admitted to the NICU for whom intravenous lipid was ordered. METHODS: Patients were randomized in pharmacy, on receipt of the order for intravenous lipid therapy, to either 72- or 24-hour administration set changes, and followed until 1 week after discontinuation of lipids or discharge from the NICU. Microbial contamination of the infusate was assessed in both groups at the time of administration set changes. Contamination rates were analyzed separately for the lipid and amino acid-glucose tubing sets. Patient charts were reviewed for clinical and epidemiological data, including birth weight, gestational age, gender, age at start of lipid therapy, duration of parenteral nutrition, and type of intravenous access. RESULTS: During the study period, 1,101 and 1,112 sets were sampled in the 72- and 24-hour groups, respectively. Microbial contamination rates were higher in the 72-hour group than the 24-hour group for lipid infusions (39/1,101 [3.54%] vs 15/1,112 [1.35%]; P=.001) and for amino acid infusions (12/1,093 [1.10%] vs 4/1,103 [0.36%]; P=.076). Logistic regression analysis controlling for birth weight, gestational age, and type of venous access showed that only the tubing change interval was significantly associated with lipid set contaminations (odds ratio, 2.69; P=.0013). The rate of blood cultures ordered was higher in the 72- versus the 24-hour group (6.11 vs 4.99 per 100 patient days of total parenteral nutrition; P=.017), and a higher proportion of infants randomized to the 72-hour group died (8% vs 4%; P=.05), although the excess deaths could not clearly be attributed to bacteremia. CONCLUSION: Microbial contamination of infusion sets is significantly more frequent with 72- than with 24-hour set changes in neonates receiving lipid solutions. This may be associated with an increased mortality rate.

Bacteremia↗
PubMed1999

Comparison of growth status of patients with cystic fibrosis between the United States and Canada.

BACKGROUND: Differences in growth status of patients with cystic fibrosis (CF) between the United States and Canada were reported in the 1980s based on analysis of data from 2 regional CF centers. OBJECTIVE: We evaluated the current growth status of the entire CF population in the United States and Canada in view of recent advances in the treatment of CF. DESIGN: Growth data from the 1992-1994 CF Patient Registries were analyzed. RESULTS: Mean height and weight were at approximately the 30th percentile for children with CF in the United States. Mean height and weight were 4-5 percentiles higher in children with CF in Canada than in those in the United States (P < 0.01), but percentages of ideal weight (104%) were similar in both populations. In adults with CF, mean height was similar at the 37th percentile; however, weight (26th compared with the 21st percentiles) and percentage of ideal weight (93% compared with 90%) were significantly higher in Canada than in the United States. Differences related to sex and age were similar in both countries for all indexes, which showed a high prevalence of underweight in infants and in older patients, but little sex discrepancy. CONCLUSION: We observed substantially smaller differences in the growth indexes of CF patients between the United States and Canada compared with results from the 1980s. These findings reflect significant improvements in the nutritional status of US patients in recent years. However, caution is required in the direct comparison of mean percentiles from reports using different growth standards because there are systematic differences in growth standards, which affect, in particular, the comparison of growth in males and females.

Adolescent↗