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Biomedical subjects

C F Doershuk

Publications and source records attributed to C F Doershuk.

At least 55 records · Page 3Linked to original sources
PubMed1983

Beta adrenergic receptors in lymphocytes and granulocytes from patients with cystic fibrosis.

Intact lymphocytes from patients with cystic fibrosis (CF) produce significantly (P less than 0.001) less adenosine 3':5' cyclic monophosphate (cAMP) than normal lymphocytes in response to isoproterenol (10(-8)-10(-4) M), although the basal cAMP content and the response to prostaglandin E1 are normal. Obligate heterozygotes for CF have significantly (P less than 0.005) reduced cAMP response to isoproterenol as well, suggesting a genetic component in the beta adrenergic deficiency in CF. The number of beta adrenergic receptors, as determined by equilibrium binding of [3H]dihydroalprenolol to lymphocyte particulates, is the same in normal lymphocytes (969 +/- 165 receptors/cell) and lymphocytes from patients with CF (1,333 +/- 263 receptors/cell). Binding properties of the receptor for both antagonist and agonist, as assessed by KD for dihydroalprenolol and Ki for (-)-isoproterenol, are also normal in the CF lymphocytes. Similarly, in granulocytes from patients with CF, the cAMP response to isoproterenol (10(-8)-10(-4) M) is significantly reduced compared with healthy controls (P less than 0.03), as is the response of granulocytes from obligate heterozygotes (P less than 0.05). Again, the basal cAMP levels and the response to prostaglandin E1 are normal. The number of beta adrenergic receptors, as determined by equilibrium binding of [3H]dihydroalprenolol to granulocyte particulates, was the same in normal (1,462 +/- 249 receptors/cell) and CF (1,621 +/- 221 receptors/cell) preparations. Binding properties of the receptor for both agonist and antagonist, as assessed by KD for dihydroalprenolol and Ki for isoproterenol, are normal in CF granulocyte particulates. The lymphocyte and granulocyte beta adrenergic defect in CF cannot be explained by abnormalities of the beta adrenergic receptor or of adenylate cyclase itself. Receptor-cyclase coupling is the most likely site of the heritable beta adrenergic defect in CF.

Adolescent↗
PubMed1983

Exercise and heat stress in cystic fibrosis patients.

Cystic fibrosis (CF) is characterized by high sweat sodium and chloride concentrations. CF patients have long been assumed to be at risk for heat illness, but there has been no quantitative documentation that CF patients actually have a greater loss of sodium and chloride than normals when under environmental stress. We compared thermoregulatory responses of eight CF patients with five normal controls during 90-min exposures to exercise and heat stress. Both groups reached similar peak rectal temperatures and peak heart rates; they had similar sweat volumes and rates. CF patients showed the normal rise in renin and aldosterone and the normal fall in urine sodium excretion; however, CF patients lost significantly more sodium (48.8 +/- 23.4 mEq/liter/m2 versus 20.2 +/- 11.2 mEq/liter/m2) and chloride (46.6 +/- 21.6 mEq/liter/m2 versus 18.5 +/- 11.3 mEq/liter/m2) per unit of surface area than the controls. Serum sodium and chloride concentrations fell in the CF patients but not in the normals. After exercise/heat stress, CF serum chloride was significantly less than normals' (99 +/- 3 mEq/liter versus 104 +/- 1 mEq/liter, P less than 0.01). CF patients have normal temperature, heart rate, hormonal, and renal responses to exercise and heat stress, yet still lose significantly more sodium and chloride than normal. These losses are reflected in part in lower serum concentrations of these ions. There may be important effects of these losses on respiratory tract secretions.

Adolescent↗
PubMed1982

Obstructive azoospermia as a diagnostic criterion for the cystic fibrosis syndrome.

In some male patients with findings characteristic of cystic fibrosis, but normal sweat chloride concentrations, the demonstration of obstruction azoospermia has been pivotal in diagnosis. It is proposed that cystic fibrosis be diagnosed if the patient has at least two of three major criteria (marked rise in sweat chloride concentration, chronic obstructive pulmonary disease and pseudomonas infection, and unexplained obstructive azoospermia) or has one major criterion together with one of several minor criteria--including positive family history and childhood onset of exocrine pancreatic insufficiency. Inclusion of unusual variants within the cystic fibrosis syndrome has major theoretical implications for pathogenesis and practical importance for genetic counselling and patient care.

Adolescent↗
PubMed1982

Treatment and prognosis of nasal polyps in cystic fibrosis.

Nasal polyposis complicated the course of fibrosis in 157 (26%) of 605 patients. Onset before age 5 years or after age 20 years was rare. Polyposis was the initial symptom of cystic fibrosis in 13 patients. Common symptoms included obstruction to nasal air flow, mouth breathing, epistaxis, and rhinorrhea. Intranasal and oral corticosteroids and antihistamines were ineffective in preventing recurrences but did occasionally afford symptomatic relief of obstruction. Nineteen (31%) of 62 patients who never had surgery had spontaneous and permanent disappearance of polyps. Simple polypectomy was an adequate procedure for patients with substantial nasal symptoms. There were no visual complications. Other surgical complications were rare. Children and adolescents with nasal polyps should have sweat tests by pilocarpine iontophoresis to rule out cystic fibrosis.

Adolescent↗
PubMed1982

Computer analysis of slow vital capacity spirograms.

We have developed a digital computer program which evaluates the vital capacity and its subdivisions, expiratory reserve volume and inspiratory capacity. The algorithm examines the multibreath spirogram, a continuous record of quiet breathing interspersed among repeated slow, large volume maneuvers. Quiet breaths are recognized by comparing features of each breath to the respective average and variation of these features for all breaths. A self-scaling, iterative procedure is used to identify those end-tidal points that most likely represent the subject's functional residual capacity. A least-squared error baseline is then fit through these points to partition the vital capacity. Twenty-three spirograms from patients with documented pulmonary disease were independently analyzed by the computer, a pulmonary function technician, and the laboratory supervisor. No practical differences were found among the results. However, the computer's values, in contrast to those of the technician, were reproducible on repeated trials and free of computational and transcriptional errors.

Computers↗
PubMed1982

Treatment and prognosis of rectal prolapse in cystic fibrosis.

Rectal prolapse occurred in 112 (18.5%) of 605 cystic fibrosis patients. In 48 patients prolapse preceded diagnosis of cystic fibrosis, but physicians (pediatricians, pediatric and general surgeons, and proctologists) rarely appreciated its importance as a symptom of this disease. Prolapses frequently cease with institution of pancreatic enzyme replacement therapy following diagnosis of cystic fibrosis. However, even when the disease remains undiagnosed, the symptom is often transient and frequently resolves at 3-5 yr of age. Prolapse occurring initially after cystic fibrosis is diagnosed rarely responds to manipulation of diet or enzyme doses. Many patients develop a method of reduction which involves voluntary abdominal, perineal, and gluteal muscles and does not require manual pressure on the prolapsed segment. Most patients do not need specific treatment for the prolapse. Surgery is rarely necessary. A sweat test should be obtained on any child who has had even a single episode of rectal prolapse.

Adolescent↗
PubMed1981

Exercise conditioning and cardiopulmonary fitness in cystic fibrosis. The effects of a three-month supervised running program.

Exercise intolerance is common in cystic fibrosis (CF). We examined the effects of a supervised three-month running program on exercise tolerance, pulmonary function, cardiorespiratory fitness (peak oxygen consumption), and respiratory muscle endurance in CF patients. We studied 31 patients, 21 exercise and ten control, aged 10 to 30 years, with pulmonary involvement ranging from mild to severe. The exercise and control groups were not significantly different with respect to age, sex, pulmonary function, exercise tolerance, or cardiorespiratory fitness. After three months of physical conditioning, the exercise group had significantly increased exercise tolerance and peak oxygen consumption and significantly lower heart rates for submaximal work loads, while the nonexercising (control) group was unchanged in all these variables. The FEV1 decreased significantly in the control group. There were no other significant changes in pulmonary function in either the control or exercise group. Respiratory muscle endurance increased significantly in the exercise patients, and did not change in the control patients. There were no adverse effects of the program. The data suggest that a supervised running program can increase CF patients' exercise tolerance and cardiorespiratory fitness, perhaps in part by increasing respiratory muscle tolerance. The effects of a much longer program deserve study.

Adolescent↗
PubMed1981

Psychosocial functioning of children with cystic fibrosis.

The adjustment of children with cystic fibrosis as rated by parents and teachers was compared to that of physically healthy siblings, normal children, and other chronically ill children. The findings indicated that children with cystic fibrosis achieved an age-adequate level of adjustment at home and school. Adjustment was largely unrelated to the severity of cystic fibrosis. As a group, chronically ill children had less adequate adjustment as rated by parents. However, severe adjustment problems were relatively rare. These findings are consistent with a growing body of literature which suggests that children with cystic fibrosis can cope reasonably well with life tasks and that emotional disturbance is not an inevitable consequence of the disease. Future studies of the cystic fibrosis population should study factors which differentiate adjusted from maladjusted children.

Adolescent↗
PubMed1980

Heart failure in cystic fibrosis. Treatment and prognosis of cor pulmonale with failure of the right side of the heart.

Failure of the right side of the heart with cardiac dilation and fluid retention occurred in 55 of 170 patients who died of cystic fibrosis; six patients survive. All had severe hypoxia, but 24% had normal PaCO2. Cardiac catheterization showed high mean pulmonary artery pressure and resistance. Pulmonary artery wedge pressure was greater than 12 mm Hg in 40% of the patients. Mean survival was eight months. Male survival was significantly better than female survival. Digitalis treatment was of no clear benefit. Tolazoline hydrochloride was also ineffective. Recent medical advances have not substantially affected prognosis.

Adolescent↗
PubMed1978

Intermediate-range sweat chloride concentration and Pseudomonas bronchitis. A cystic fibrosis variant with preservation of exocrine pancreatic function.

We studied the clinical and laboratory characteristics of seven patients with sweat chloride concentration consistently between 40 and 60 mEq/liter. Each has chronic Pseudomonas bronchitis, and all lack digestive symptoms. Laboratory findings indicate the preservation of exocrine pancreatic function. The patients include two of five children in one family and two of four in another. In a third family, one of five siblings has an intermediate sweat chloride concentration, but another has a typical fibrosis value (105 mEq/liter). One patient died of respiratory failure; results of an autopsy showed bronchiolectasis typical of cystic fibrosis, but minimal pancreatic changes. The data suggest a genetic basis for this variant of cystic fibrosis. These patients may be homozygous for a portion of a closely linked multigene cystic fibrosis locus or may have modifier genes that ameliorate the pancreatic and sweat lesions.

Adolescent↗
PubMed1978

Treatment and prognosis of lobar and segmental atelectasis in cystic fibrosis.

Lobar atelectasis occurred in 30 (4.1 per cent) and segmental atelectasis occurred in 6 (0.8 per cent) of 728 patients with cystic fibrosis. The right lung was involved in all 11 patients less than 5 years of age and in 18 of 26 episodes in 19 older patients. Five of the younger patients died within 5 years of the initial episode. Bronchoscopy (with or without local lavage) performed in addition to intensified medical therapy did not appear to improve the outcome. Future studies of therapeutic measures (including bronchoscopy) for treatment of atelectasis complicating cystic fibrosis must include appropriate control patients who receive only medical therapy.

Adolescent↗
PubMed1978

Cystic fibrosis: the prognosis for five-year survival.

Statistical discriminant analysis is applied to 41 concomitant variables obtained during the first year of study of 226 patients with cystic fibrosis. A discriminant function based on six variables is developed which can be used as a predictive index. This index estimates the probability of 5-year survival for an individual patient and can also be used to classify patients into one of two groups: (1) will live for 5 years or (2) will die within 5 years. Speculation A classification rule for cystic fibrosis is presented which correctly assigns 90% of the 5-year survivors and 84% of those who expire. Such a classification scheme is useful for clinical and research purposes.

Adolescent↗