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Biomedical subjects

M Corey

Publications and source records attributed to M Corey.

At least 73 records · Page 4Linked to original sources

Factors influencing postoperative recurrence of Crohn's disease in childhood.

We have reviewed the outcome of all patients undergoing their first intestinal resection for Crohn's disease at this hospital between 1970 and 1987. Recurrence rates, defined by recurrent intestinal symptoms and radiological confirmation of mucosal disease, were calculated using survival analysis. Age, sex, anatomical location of disease, indication for surgery, preoperative duration of symptomatic disease, use of preoperative bowel rest, and pathological features of the resected bowel were analysed individually and jointly as potential risk factors influencing postoperative recurrence of disease. Eighty two patients (age, mean (SD) 14.8 (2.5) years) underwent intestinal resection and were followed postoperatively for a minimum of one year (mean 5.3 (3.3) years). Anatomical location of disease, indication for surgery, and preoperative duration of symptomatic disease were the only factors that significantly influenced the duration of the recurrence free interval. Patients with diffuse ileocolonic inflammation experienced earlier recurrence (50% at one year) than children with predominantly small bowel disease (50% recurrence at five years, p less than 0.0001). Failure of medical therapy independent of disease location as the sole indication for surgery was associated with an earlier relapse than when surgery was performed for a specific intestinal complication such as abscess or obstruction (p less than 0.003). Patients undergoing resection within one year of onset of symptoms experienced delayed recrudescence of active disease (30% recurrence by eight years) compared with patients whose preoperative duration of symptomatic disease was longer (50% recurrence by four years when preoperative duration of disease was one to four years and 50% by three years when disease had been present greater than four years preoperatively, p = 0.03). The mean height velocity of patients with growth potential increased from 2.4 (2.3) cm per year preoperatively to 8.1 (3.4) cm per year in the first postoperative year (p=0.0001). These results support an early approach to surgery in the management of ileal Crohn's disease with or without caecal or right colonic involvement, especially when complicated by persistent growth failure. The higher recurrence rates in more diffuse ileocolonic disease emphasise the need for alternative treatment strategies in these children.

Adolescent↗

Effect of refeeding on the energy metabolism of adolescent girls who have anorexia nervosa.

The effect of refeeding on resting energy expenditure (REE) and substrate utilization was studied in 18 hospitalized adolescent girls (aged 12.9-19.1 years) suffering from anorexia nervosa. Changes in body composition were monitored weekly and included weight, fat body mass (FBM), lean body mass (LBM) and total body potassium (TBK). REE was studied weekly by open-circuit calorimetry. Weight gain was noted in all patients (38.2 +/- 5.6 to 44.5 +/- 5.3 kg), involving increased FBM and LBM. REE increased per kg of weight (91.6 +/- 15.1 to 101.7 +/- 18.0 kJ kg-1 d-1) and LBM over the first weeks of refeeding (P less than 0.025) and then stabilized. Substrate utilization showed an increase in carbohydrate and protein utilization (P less than 0.001) during the first few weeks of refeeding. We also studied the thermic effect of food (TEF) in 14 of the 18 subjects. Upon admission the subjects had a reduced TEF (36.4 +/- 24.3 kJ 2 h-1) (P less than 0.001). With refeeding TEF rose to a peak or plateau, then decreased to normal levels (61.9 +/- 36.0 kJ 2 h-1) before discharge from hospital. We conclude that the energy metabolism of adolescent girls adapts to semi-starvation by a reduction in both REE and TEF; with refeeding there is reversal of this adaptive function.

Adolescent↗

Pregnancy and cystic fibrosis.

Despite reduced fertility, pregnancy is likely to occur with increasing frequency in cystic fibrosis in proportion to the number of patients reaching childbearing age. Thirty-eight pregnancies in 25 patients with cystic fibrosis are presented. Twelve of the 25 mothers were pancreatic-sufficient. Despite previous reports of the hazards of pregnancy in cystic fibrosis, we found that pregnancy was well tolerated by the vast majority of our patients and had little effect on their pulmonary and nutritional status. Therapeutic abortion for medical indications was required in two pregnancies. The incidence of prematurity and the neonatal mortality rate were low, and no congenital abnormalities occurred. We conclude that pregnancy can be tolerated by the majority of cystic fibrosis patients, particularly those who are pancreatic-sufficient.

Adolescent↗

The relation between genotype and phenotype in cystic fibrosis--analysis of the most common mutation (delta F508).

BACKGROUND AND METHODS: Both the clinical manifestations of cystic fibrosis and the genotypes of patients are heterogeneous, but the associations between the two are not known. We therefore studied blood samples from 293 patients with cystic fibrosis for the presence of the most common disease-causing mutation (delta F508) on chromosome 7 and compared the results with the clinical manifestations of the disease. RESULTS: The prevalence of the delta F508 allele in the cohort was 71 percent; 52 percent of the patients were homozygous for the mutation, 40 percent were heterozygous, and 8 percent had other, undefined mutations. The patients who were homozygous for the mutation had received a diagnosis of cystic fibrosis at an earlier age and had a greater frequency of pancreatic insufficiency; pancreatic insufficiency was present in 99 percent of the homozygous patients, but in 72 percent of the heterozygous patients and only 36 percent of the patients with other genotypes. The patients with pancreatic insufficiency in all three genotype groups had similar clinical characteristics, reflected by an early age at diagnosis, similar sweat chloride values at diagnosis, similar severity of pulmonary disease, and similar percentiles for weight. In contrast, the patients in the heterozygous-genotype and other-genotype groups who did not have pancreatic insufficiency were older and had milder disease. They had lower sweat chloride values at diagnosis, normal nutritional status, and better pulmonary function after adjustment for age. CONCLUSIONS: The variable clinical course in patients with cystic fibrosis can be attributed at least in part to specific genotypes at the locus of the cystic fibrosis gene.

Adolescent↗

Pulmonary function and clinical course in patients with cystic fibrosis after pulmonary colonization with Pseudomonas aeruginosa.

To evaluate the relationship between Pseudomonas aeruginosa colonization and the development of lung disease, we studied 895 patients who attended our cystic fibrosis clinic between 1975 and 1988. The prevalence of P. aeruginosa colonization was 82%. Patients who acquired P. aeruginosa in the first year of life had a similar 10-year survival rate (85%) to that in patients who were colonized between the ages of 1 and 7 years (87%), and to that in patients colonized after the age of 7 years (78%). One year before colonization, mean age, forced expiratory volume in 1 second (FEV1), forced vital capacity, and forced expiratory flow in the mid-expiratory phase were similar to those in a group of patients who remained free of P. aeruginosa. No significant change in pulmonary function variables could be demonstrated 1 year and 2 years after the colonization. The rate and duration of hospitalization did not increase in the years after P. aeruginosa colonization compared with the years before colonization. By the age of 7 years, the mean percentage of predicted FEV1 was lower by 10% in patients who were already colonized by P. aeruginosa compared with those who were not colonized (p less than 0.01). A similar reduction in FEV1 was observed at all ages from 7 to 35 years, but no precipitate rate of decline in FEV1 could be associated with P. aeruginosa colonization. We conclude that although P. aeruginosa colonization is associated with 10% lower lung function, it does not cause an immediate and rapid reduction, as has been previously reported. The clinical course and the pulmonary deterioration in cystic fibrosis after P. aeruginosa colonization is a gradual and variable process.

Adolescent↗

Effects of cisapride in patients with cystic fibrosis and distal intestinal obstruction syndrome.

In a double-blind, placebo-controlled, crossover trial, we investigated the effects of the prokinetic drug cisapride in patients with cystic fibrosis and chronic recurrent distal intestinal obstruction syndrome (DIOS). After a baseline period, 17 patients (12.9 to 34.9 years; 12 boys) received, in random order, cisapride (7.5 to 10 mg) and placebo three times daily by mouth, each for 6 months. Gastrointestinal symptoms (flatulence, abdominal pain, fullness, abdominal distension, nausea, anorexia, heartburn, diarrhea, vomiting and regurgitation) were scored three times monthly and physical examinations assessed. At baseline and at each 6-month period, assessment included food intake for 7 days, 3-day stool collection, pulmonary function tests, and abdominal radiographs. During cisapride therapy compared with placebo, there were significant reductions in flatulence (p less than 0.005), fullness, and nausea (p less than 0.05). Patients with the worst symptom scores benefited most from cisapride. With cisapride, 12 patients felt better and three worse (p less than 0.05); physicians judged 11 patients improved and two worse (p less than 0.05). No side effects were noted. There were no significant differences between cisapride and placebo periods in nutritional status, x-ray scores, pulmonary function, food intake (fat, protein, calories), stool size and consistency, and fecal losses of fat, bile acids, chymotrypsin, and calories. For acute episodes of DIOS, intestinal lavage was needed 6 times in 4 patients during treatment with cisapride, and 11 times in 6 patients receiving placebo. In comparison with unselected patients with cystic fibrosis and pancreatic insufficiency who were receiving enzyme supplements and who had no distal intestinal obstruction, fecal fat losses (percentage of intake) were almost twice as high in the study group with DIOS (31.2 +/- 20.6% vs 16.2 +/- 17.6%; p less than 0.01). We conclude that in the dosage used, long-term treatment with cisapride appears to improve chronic abdominal symptoms in patients with cystic fibrosis and DIOS, but fails to abolish the need for intestinal lavage. Cisapride treatment had no effect on digestion and nutritional status of cystic fibrosis patients with pancreatic insufficiency.

Adolescent↗

Risk factors for Pseudomonas aeruginosa colonization in cystic fibrosis patients.

In an attempt to study the association between Pseudomonas aeruginosa colonization and clinical factors present before colonization, we studied 502 patients who attended our cystic fibrosis (CF) clinic between 1975 and 1988 and who were not colonized with P. aeruginosa before the study period. Twelve percent of the patients became colonized with P. aeruginosa before the age of 1 year and 44% by the age of 7 years. In a birth cohort followed from diagnosis during the study period, 23% were colonized with P. aeruginosa before age 1 year and 67% before age 7 years. Early P. aeruginosa colonization was associated with early diagnosis of CF. Presence of meconium ileus, gastrointestinal symptoms and pancreatic insufficiency at the time of diagnosis was also associated with early colonization. There was no association between the presence of respiratory symptoms at the time of diagnosis and age at first P. aeruginosa colonization. In families in which more than one sibling had CF, the age of P. aeruginosa acquisition was similar in the first colonized and the subsequently colonized siblings. In the year before the colonization patients with P. aeruginosa who were older than 1 year had higher rates of hospitalization and spent more days in hospital compared with patients without P. aeruginosa. In conclusion most P. aeruginosa colonization occurs at a younger age than previously reported. Early age at diagnosis and presence of CF-associated gastrointestinal abnormalities increase the likelihood of earlier colonization of P. aeruginosa.

Age Factors↗

Diabetes mellitus in patients with cystic fibrosis: effect on survival.

Patient data obtained from the cystic fibrosis clinic of the Hospital for Sick Children (Toronto, Canada) over the period 1977 to 1988 were analyzed to compare the diabetic and nondiabetic cystic fibrosis patients. The pulmonary function, nutritional status, and survival data for 713 patients who attended the clinic over the 11-year period are reported. Insulin-dependent diabetes was found to exist in 37 (5.2%) of 713 patients. The patient age at time of diabetes diagnosis ranged from 2 to 34 years, with a mean +/- SD of 20.0 +/- 7.4 years. Patients who died in both the diabetic and nondiabetic groups had worse pulmonary and nutritional status than the surviving patients, but there were no significant differences between the diabetic and nondiabetic groups in those who died or in those who remained alive. Survival analysis showed a similar prognosis in the diabetic and nondiabetic groups. It is concluded that cystic fibrosis patients with diabetes are, for their age, not different from patients without diabetes with respect to pulmonary function, nutritional status, and survival.

Adolescent↗

Long-term effects of inhaled tobramycin in patients with cystic fibrosis colonized with Pseudomonas aeruginosa.

Twenty-seven patients with cystic fibrosis and endobronchial colonization with Pseudomonas aeruginosa were randomly assigned to inhale either 2 mL saline (12 patients) or 80 mg tobramycin solution (15 patients) 3 times daily. One control patient died; all others completed the study (mean duration 32 months). No significant differences were found between the two groups at enrollment. The treatment group showed no change, while the control group had a significant decline in both pulmonary function and clinical status over the study period. Individually, 11 of 12 patients in the control group showed deterioration, while 9 of 15 in the treatment group with susceptible P. aeruginosa at enrollment acquired resistant organisms. There was no evidence of significant nephro- or ototoxicity. Although inhaled tobramycin appeared to arrest the decline in pulmonary status, further work is required to identify patients most likely to respond.

Administration, Inhalation↗

Clinical and genetic comparisons of patients with cystic fibrosis, with or without meconium ileus.

We set out to determine if the clinical course or genetic profiles of patients with cystic fibrosis who had meconium ileus differed from those of other patients with cystic fibrosis. Since 1950 we have followed 158 patients with meconium ileus among 1175 patients with cystic fibrosis (13.4%). Patients with meconium ileus had lower birth weight (3026 +/- 610 gm) than patients with no meconium ileus (3169 +/- 534 gm; p less than 0.008); the deficit was especially evident in female patients. Survival in the first year of life increased from 55% in those born between 1958 and 1972 to 96% in those born between 1973 and 1987. Since 1973 the median survival of male and female patients with meconium ileus was similar to that in female patients with no meconium ileus (21 years), whereas 78% of males with no meconium ileus survived to this age (p less than 0.0001). Patients with meconium ileus born before 1972 had lower weight and height percentiles at age 13 years compared with patients with no meconium ileus, but this difference was not as apparent in patients born after 1973. There were no differences between the two groups in forced vital capacity, forced expiratory volume in 1 second, or forced expiratory flow in the middle half of forced vital capacity. Patients with meconium ileus acquired Pseudomonas aeruginosa at a younger age than did patients with no meconium ileus (4.20 +/- 4.67 vs 7.18 +/- 5.19 years), but there was no difference in age of acquisition of P. cepacia. In families in which the first child had meconium ileus, 29% of subsequent siblings with cystic fibrosis had meconium ileus, compared with 6% of siblings born to families in which the first child did not have meconium ileus. Allelic frequencies and haplotypic variants for cystic fibrosis chromosomes with respect to DNA markers closely linked to the cystic fibrosis locus were similar in families with cystic fibrosis with meconium ileus and those with no meconium ileus. These findings suggest that patients with cystic fibrosis and those without meconium ileus do not have major intrinsic differences and that the previously poor outlook in patients with meconium ileus has improved greatly.

Adolescent↗

Nocturnal home oxygen in the treatment of hypoxemic cystic fibrosis patients.

The effect of nocturnal oxygen therapy on mortality and morbidity rates and on progression of disease was tested in a double-blind, randomized trial of 28 subjects with advanced cystic fibrosis. Patients were selected on the basis that their awake arterial oxygen tension was less than 65 mm Hg when they were clinically stable. Oxygen was prescribed in 1 L/min increments to obtain an awake arterial oxygen tension of greater than or equal to 70 mm Hg. Subjects received humidified oxygen or room air from modified concentrators. They were enrolled over a 3-year period and followed for an average (+/- SD) of 26 +/- 9 months. The average number of hours per night of concentrator use was 5.3 +/- 3.2 hours in the air group and 7.0 +/- 1.9 hours in the oxygen group. Over the follow-up period there were four deaths in each group, and oxygen therapy had no significant effect on the frequency of hospitalizations. Progression of disease was ascertained from nutritional status, pulmonary function, blood gas values, exercise ability, and right ventricular ejection fraction response to exercise (as measured by equilibrium-gated radionuclide angiocardiography), and psychologic status was measured by standardized tests of mood, self-esteem, and cognitive function; group comparisons for the first year revealed no significant differences; however, school or work attendance was maintained in the oxygen group but deteriorated in the air group. Clinical signs of cor pulmonale were documented during follow-up in 10 patients in toto, and all lived at least 9 months from the onset of these signs. The lack of association between the onset of these signs and imminent death, or the usefulness of measurements of the maximal oxygen uptake during progressive exercise and the right ventricular ejection fraction response to exercise as prognostic indicators, suggest that death may not be the result of cor pulmonale. We conclude that nocturnal oxygen treatment in patients with cystic fibrosis did not appear to affect mortality rates, the frequency of hospitalizations, or the progression of disease; oxygen use should be instituted only after the development of symptoms related to hypoxemia.

Adult↗

Origins of chloride and bicarbonate secretory defects in the cystic fibrosis pancreas, as suggested by pancreatic function studies on control and CF subjects with preserved pancreatic function.

Pancreatic function studies were performed under continuous intravenous stimulation with secretin and cholecystokinin (0.125 mu/kg/min) in 40 patients with CF who had no evidence of steatorrhea and 69 control subjects without CF, who also lacked evidence of steatorrhea. A total of 41 studies in CF patients and 74 in control subjects were analysed for trypsin, electrolyte, and water secretion. 51% of the CF and 51% of the control tests showed trypsin secretion responses between 1000 mu/kg/hr (the lower limit of the normal range) and 2695 mu/kg/hr, while 16.2% of the control tests exceeded this range. Secretion of water and electrolytes, including both chloride and bicarbonate, was significantly lower in the CF subjects when compared to the appropriate controls in the normal and subnormal trypsin output range. Chloride-bicarbonate ratios, although higher in subjects with evidence of pancreatic damage, were identical in CF and control studies. A specific ductal lesion in CF which altered the balance of acinar (predominately chloride) and ductal (predominately bicarbonate) secretion, or encouraged the equilibration of ductal fluid with plasma in the distal ducts, would increase chloride-bicarbonate ratios, as in the subjects with reduced trypsin secretion. Since this did not occur in the patients with normal function, our results suggest that chloride and bicarbonate secretions are impaired to a similar extent in CF, possibly through a dependence on the same phenotypic abnormality.

Bicarbonates↗

Impaired chloride secretion, as well as bicarbonate secretion, underlies the fluid secretory defect in the cystic fibrosis pancreas.

Pancreatic fluid and electrolyte secretion was assessed in 56 patients with cystic fibrosis (CF) and 56 non-CF control subjects undergoing pancreatic function testing while stimulated with cholecystokinin and secretin. Both CF patients and control subjects exhibited a wide range of pancreatic function. Fluid and trypsin outputs were positively correlated in both groups. Fluid output in CF subjects was significantly lower, however, than that of control subjects at any given level of trypsin output. Sodium, bicarbonate, and chloride secretions were all significantly decreased in CF subjects. Bicarbonate and chloride were important determinants of fluid secretion, but at any given bicarbonate or chloride output CF subjects secreted significantly less fluid than control subjects. When bicarbonate and chloride were analyzed as simultaneous predictor variables, adjusted fluid secretion was not significantly different in CF and control subjects. Diminished fluid secretion in CF subjects is therefore caused by impaired chloride, as well as bicarbonate, secretion.

Bicarbonates↗