A novel missense mutation in patients from a retinoblastoma pedigree showing only mild expression of the tumor phenotype

We have used single strand conformation polymorphism analysis to study the 27 exons of the RB1 gene in individuals from a family showing 'mild' expression of the retinoblastoma phenotype. In this family affected individuals developed unilateral tumors and, as a result of linkage analysis, unaffected mutation carriers were also identified within the pedigree. A single band shift using SSCP was identified in exon 21 which resulted in a missense mutation converting a cys-->arg at nucleotide position 28 in the exon. The mutation destroyed an NdeI restriction enzyme site. Analysis of all family members demonstrated that the missense mutation co-segregated with patients with tumors or who, as a result of linkage analysis had been predicted to carry the predisposing mutation. These observations point to another region of the RB1 gene where mutations only modify the function of the gene and raise important questions for genetic counseling in families with these distinctive phenotypes.     

Assessment of fitness in patients with cystic fibrosis and mild lung disease

The purpose of this investigation was to examine if exercise-induced arterial oxyhemoglobin desaturation selectively observed in highly trained endurance athletes could be related to differences in the pulmonary diffusing capacity (DL) measured during exercise. The DL of 24 male endurance athletes was measured using a 3-s breath-hold carbon monoxide procedure (to give DLCO) at rest as well as during cycling at 60% and 90% of these previously determined VO2max. Oxyhemoglobin saturation (SaO2%) was monitored throughout both exercise protocols using an Ohmeda Biox II oximeter. Exercise-induced oxyhemoglobin desaturation (DS) (SaO2% < 91% at VO2max) was observed in 13 subjects [88.2 (0.6)%] but not in the other 11 nondesaturation subjects [NDS: 92.9 (0.4)%] (P < or = 0.05), although VO2max was not significantly different between the groups [DS: 4.34 (0.65) l/min vs NDS: 4.1 (0.49) l/min]. At rest, no differences in either DLCO [ml CO.mmHg-1.min-1: 41.7 (1.7) (DS) vs 41.1 (1.8) (NDS)], DLCO/VA [8.2 (0.4) (DS) vs 7.3 (0.9) (NDS)], MVV [l/min: 196.0 (10.4) (DS) vs 182.0 (9.9) (NDS)] or FEV1/FVC [86.3 (2.2) (DS) vs 82.9 (4.7) (NDS)] were found between groups (P > or = 0.05). However, VE/VO2 at VO2max was lower in the DS group [33.0 (1.1)] compared to the NDS group [36.8 (1.5)] (P < or = 0.05). Exercise DLCO (ml CO.mmHg-1.min-1) was not different between groups at either 60% VO2max [DS: 55.1 (1.4) vs NDS: 57.2 (2.1)] or at 90% VO2max [DS: 61.0 (1.8) vs NDS: 61.4 (2.9)]. A significant relationship (r = 0.698) was calculated to occur between SaO2% and VE/VO2 during maximal exercise. The present findings indicate that the exercise-induced oxyhemoglobin desaturation seen during submaximal and near-maximal exercise is not related to differences in DL, although during maximal exercise SaO2 may be limited by a relatively lower exercise ventilation.     

Thirteen cystic fibrosis patients, 12 compound heterozygous and one homozygous for the missense mutation G85E: a pancreatic sufficiency/insufficiency mutation with variable clinical presentation

To study the severity of mutation G85E, located in the first membrane spanning domain of the CFTR gene, we studied the clinical features of 13 Spanish patients with cystic fibrosis (CF) carrying this mutation. G85E accounts for about 1% of Spanish CF alleles. One patient was homozygous G85E/G85E and the rest were compound heterozygotes for G85E and other mutations (delta F508 nine patients, delta I507 two patients, and 712-1G > T one patient). The characteristics of the pooled G85E/any mutation group were compared with those of 30 delta F508 homozygotes. Mean age at diagnosis and percentage of ideal height for age were higher in the G85E/any mutation group (4.2 (SD 4.7) v 2.4 (SD 2.3), p < 0.05, and 102.8 (SD 4.7) v 97.8 (SD 4.1), p < 0.01), both probably related to the greater prevalence of pancreatic sufficiency (70% v 0%, p < 0.01). The G85E homozygote was pancreatic sufficient. Sweat sodium levels were slightly higher, and salt loss related problems more frequent, in the G85E/any group. Two of the G85E patients died of respiratory failure aged 6 and 14 years. Striking discordance in the phenotype was observed in two pairs of sibs, one of them dizygotic twins, suggesting that factors, genetic and environmental, other than CFTR genotype are important in determining CF phenotype.     

Four years' experience of intravenous colomycin in an adult cystic fibrosis unit

Nearly all strains of Pseudomonas aeruginosa are sensitive to colomycin sulphomethate, but studies in the 1970s using large doses demonstrated significant renal and neurotoxic side-effects and it is not now commonly used. In this study colomycin (2 megaunits i.v. t.d.s.) has been used extensively in adult cystic fibrosis (CF) patients and its use reviewed to determine its efficacy and safety profile. Fifty-two CF patients (28 male, 24 female; mean age 26 yrs, range 17-39 yrs) received 135 courses (mean two courses each, range 1-7, median length 14 days) of i.v. colomycin (2,414 patient days in total). It was used in combination with one other i.v. antibiotic in 114 courses (85%) and with two others in 18 (13%). In all cases there was significant improvement in spirometry (pretreatment forced expiratory volume in one second (FEV1) % predicted mean 44.4, range 10-101; post-treatment mean 51.3, range 14-108; p<0.0001). No patient had any neurotoxicity but one developed a skin rash and myositis. There was no change in renal function (urea mean pretreatment 4.1 mmol x L(-1) (sD 1.4), mean post-treatment 43 (2.2), p=NS; creatinine mean pretreatment 77.9 mmol x L(-1) (15.3), mean post-treatment 803 (21.6), p=NS). In the authors' experience intravenous colomycin sulphomethate in moderate doses is an effective and safe antipseudomonal antibiotic which is easy to administer. Other clinicians should consider its use in patients with cystic fibrosis.     

Totally implantable venous access devices in adult patients with cystic fibrosis

Between September 1987 and April 1995, 33 totally implantable venous access devices (TIVADs) were implanted at the Cardiff Adult Cystic Fibrosis Centre, U.K., for the purpose of intermittent antibiotic therapy, including 22 PORT-A-CATH (Simcare Ltd.) devices (PCs) to 18 patients, and 11 P.A.S.PORT (Simcare Ltd.) devices (PPs) to nine patients. There were 50 complications during 25 824 days of catheter function which were severe enough to lead to removal of the devices in eight patients (six PCs and four PPs). Overall, patients' acceptance of these devices was excellent. Despite a shorter functional time and a higher rate of complications in PPs compared with PCs, PPs were preferred by many patients for cosmetic reasons. Totally implantable venous access devices provide safe, effective and convenient means of venous access in cystic fibrosis patients requiring intermittent antibiotic therapy.     

Prevalence of allergic bronchopulmonary aspergillosis and atopy in adult patients with cystic fibrosis

BACKGROUND: Underestimation of allergic bronchopulmonary aspergillosis (ABPA) prevalence in the cystic fibrosis (CF) population is suspected due to nonuniform diagnostic criteria, nonspecific signs and symptoms, assessment during asymptomatic intervals, and physician nonaggressiveness in making the diagnosis. OBJECTIVE: To define the prevalence of ABPA in adult patients with CF, as the increased duration of bronchiectasis may increase the probability of Aspergillus fumigatus (Af) colonization. We also sought to determine whether atopy increases the prevalence of ABPA in adults with CF. METHODS: We examined a cross-sectional population of adult patients with CF at the University of Washington for 1 year. RESULTS: Information was collected on 53 of 65 (82%) patients. Fifteen of 51 (29%) had an immediate skin test reaction to Af, and 30 of 51 (59%) had at least one positive skin test. Increased total serum IgE (>450 IU/mL) was present in 0 of 53; increased IgE-Af and IgG-Af were found in 12 of 53 (23%) and 9 of 53 (17%), respectively; 24 of 53 (45%) had Af-precipitins. Peripheral blood eosinophilia was present in one patient. Eight of 49 (16%) patients' sputum cultures grew Af. ABPA-CB (ABPA-central bronchiectasis) was present in one patient and ABPA-S (ABPA-seropositive) in no patients. Atopy was present in 20 of 51 (39%). CONCLUSION: There was a low prevalence of ABPA in the adult CF population despite frequent immunologic responses to Af. The prevalence of ABPA was too small to determine an association with atopy.     

Pregnancy in patients with cystic fibrosis

With increasing life span of patients with CF, more women with CF are becoming pregnant and others are seeking information about the risks involved during pregnancy and delivery. A striking limitation of the available information is the lack of large prospective studies of pregnant patients with CF matched for age and disease severity compared with their non-pregnant cohorts. A study investigating the effect of pregnancy on morbidity and mortality is being completed by the Cystic Fibrosis Foundation. We recommend that all women with CF be offered contraceptive measures and counseling on the maternal and fetal risks of pregnancy, including the genetic risks for the child. The issue of who will raise the child in the event of subsequent morbidity or maternal mortality should ideally be prospectively discussed.     

Osteoporosis in patients with cystic fibrosis

Decreased bone density and increased risk of fractures are seen in patients with cystic fibrosis. Suboptimal vitamin D levels, nutrition problems, hypogonadism, inactivity, corticosteroid use, and cytokines may contribute to the low bone mass seen in these patients. Treatment recommendations must be individualized and may include nutrition, vitamin D, estrogen or testosterone, and exercise. In high-risk patients calcitonin or growth hormone could be considered.     

G542X as a probable Phoenician cystic fibrosis mutation

Only one prior study has examined social competence (SC) in drug addicted individuals. That study of cocaine-addicted individuals found gender differences in SC as well as differences based on the type of comorbid psychiatric diagnoses given. This study attempts to replicate findings from that cocaine study in a sample of opiate-addicted individuals and explores the relationship of SC to short-term treatment response. Gender differences in SC were examined in 28 women and 44 men attending a community methadone maintenance program. The question of differences in SC based on comorbid psychiatric diagnoses and treatment response were examined in a sample of 198 men attending a Veterans Administration methadone program. Women were found to have significantly lower SC than men. No significant differences in SC were revealed based on the presence of specific psychiatric diagnoses. SC was not related to short-term treatment response.     

Clinical denouement and mutation analysis of patients with cystic fibrosis undergoing liver transplantation for biliary cirrhosis

OBJECTIVE: To describe the clinical characteristics of patients with cystic fibrosis considered for liver transplantation and the clinical outcome after transplantation. METHODS: Patient charts were reviewed. Mutation analysis was performed on blood or liver tissue samples with a panel of 17 mutations. RESULTS: Eight patients (five girls) with cystic fibrosis have undergone orthotopic liver transplantation for biliary cirrhosis. Mean age at transplantation was 12.0 years +/- 7.7 years (range, 9 months to 23 years). Preoperatively, seven patients had mild to moderate pulmonary dysfunction and one moderate to severe pulmonary dysfunction. All patients required pancreatic enzyme replacement, and four patients required insulin for diabetes mellitus. The 1-year survival rate was 75%, with no deaths related to septic events. Mean time of follow-up the six operative survivors was 4.1 years +/- 1.9 years. Pulmonary function testing, in those serially tested, showed that forced expiratory volume in 1 second was maintained or improved and that forced vital capacity improved after transplantation. Mutation analysis showed the following genotypes: four patients, delta F508/delta F508; one patient, delta F508/N1303K; and three patients, delta F508/unknown. CONCLUSIONS: Despite the high risk of transplantation, these encouraging results indicate that liver transplantation should be considered for patients with cystic fibrosis and complications of end-stage liver disease. We could not demonstrate an unusual pattern of CF gene mutations in these patients with severe liver disease. It appeared that immunosuppressive agents did not have a deleterious effect on pulmonary function.     

Pediatric and adult lung transplantation for cystic fibrosis

OBJECTIVE: This paper was undertaken to review the experience at our institution with bilateral sequential lung transplantation for cystic fibrosis. METHODS: Since 1989, 103 bilateral sequential lung transplants for cystic fibrosis have been performed (46 pediatric, 48 adult, 9 redo); the mean age was 21 +/- 10 years. Cardiopulmonary bypass was used in all but one pediatric (age <18) transplant, and in 15% of adults. RESULTS: Hospital mortality was 4.9%, with 80% of early deaths related to infection. Bronchial anastomotic complications occurred with equal frequency in the pediatric and the adult populations (7.3%). One- and 3-year actuarial survival are 84% and 61%, respectively (no significant difference between pediatric and adult age groups; average follow-up 2.1 +/- 1.6 years). Mean forced expiratory volume in 1 second increased from 25% +/- 9% before transplantation to 79% +/- 35% 1 year after transplantation. Acute rejection occurred 1.7 times per patient-year, with most episodes taking place within the first 6 months after transplantation. The need for treatment of lower respiratory tract infections occurred 1.2 times per patient in the first year after transplantation. Actuarial freedom from bronchiolitis obliterans was 63% at 2 years and 43% at 3 years. Redo transplantation was performed only in the pediatric population and was associated with an early mortality of 33%. Eight living donor transplants (four primary transplants, four redo transplants) were performed with an early survival of 87.5%. CONCLUSION: Patients with end-stage cystic fibrosis can undergo bilateral lung transplantation with morbidity and mortality comparable to that seen in pulmonary transplantation for other disease entities.     

Exercise testing and prognosis in adult cystic fibrosis

PURPOSE: The objective of our study was to determine the maximum tolerable doses (MTDs) of both paclitaxel and cisplatin when given in a weekly schedule alone or simultaneously with G-CSF in advanced solid neoplasms. PATIENTS AND METHODS: Patients with advanced cancer either chemotherapy-naive or resistant to standard treatments received paclitaxel in a three-hour infusion followed by cisplatin, with or without the addition of r-HuG-CSF (5 micrograms/kg s.c. days three to five). The starting doses of CDDP and paclitaxel were 25 mg/m2/week and 45 mg/m2/week, respectively. During the first six courses the dosages of the two drugs were alternately escalated by 20% (CDDP = 5 mg/m2/week, and paclitaxel 10 mg/m2/week) at each step until the appearance of dose-limiting toxicity (DLT) in one-third or more of the patients enrolled in that cohort. RESULTS: Fifty-five patients with cancer (16 lung, 16 breast, 11 ovarian, 7 head and neck, 1 renal, 1 esophageal, 1 cervical, 1 soft-tissue sarcoma, and 1 of unknown primary), 25 of whom were pretreated, were entered into the study. A total of 439 weekly courses were delivered. In chemotherapy-na?ve patients, the MTDs of cisplatin and paclitaxel were 30 mg/m2/week and 65 mg/m2/week, respectively, in the absence of G-CSF support, which increased to 40 mg/m2/week and 85 mg/m2/week, respectively, when G-CSF was given. There were no toxic deaths in this study. Neutropenia was the main dose-limiting toxicity (100/439 courses), but was seldom severe. Neurotoxicity was quite frequent (18 of 55 patients for the total of 88 courses) but never dose-limiting. It was more frequent and clinically relevant in cisplatin-pretreated patients. Overall 18 patients (eight ovarian, five breast, three lung, and two head and neck) achieved objective responses. CONCLUSIONS: The cisplatin-paclitaxel weekly administration seems a safe, practical and effective therapeutical approach in patients with advanced solid neoplasms. Large phase II trials are warranted to accurately define the efficacy of this schedule in cisplatin-paclitaxel sensitive tumors.     

A dystrophin missense mutation showing persistence of dystrophin and dystrophin-associated proteins yet a severe phenotype

A muscle biopsy from an X-linked muscular dystrophy pedigree showed normal dystrophin and dystrophin-associated proteins. Linkage to multiple markers within the dystrophin gene (LOD=2.7, theta=0) indicated a primary dystrophinopathy. Sequencing of the entire dystrophin RNA revealed a single missense mutation (D3335H) in the unique carboxyl-terminal domain. This is the first report showing that a relatively severe dystrophinopathy can occur despite the correct localization of dystrophin and dystrophin-associated proteins.     

Glucose tolerance in patients with cystic fibrosis

In order to define prevalence and incidence of diabetes mellitus in cystic fibrosis, we followed 191 unselected patients above two years of age (median 13.6) in a five-year prospective study with annual oral glucose tolerance tests. The prevalence of diabetes increased from 11 to 24% during the study period with an annual age-dependent incidence rate of 4-9%. Diabetes was diagnosed at a median age of 21 years (range 3-40). At diagnosis of diabetes, hyperglycaemia, fasting hyperglycaemia (> or = 7.8 mmol/l), and increased haemoglobin Alc levels (> 6.4) were present in 33%, 16% and 16% of the diabetic patients, respectively. Impaired glucose tolerance implied a higher risk than normal glucose tolerance for the development of diabetes (odds ratio 5.6). In 58% of cases with impaired glucose tolerance, however, glucose tolerance was normalised at the next annual test. Normal glucose tolerance was found in only 37% of the patients at all five tests. Within this group of patients, median fasting and two-hour post-load plasma glucose concentrations and haemoglobin Alc levels increased by 6-8% during five years. Thus, the prevalence and incidence of diabetes in patients with cystic fibrosis is very high and increases with age. Since symptoms of hyperglycaemia and increased fasting plasma glucose and haemoglobin Alc levels are inconstant findings in newly diagnosed diabetic cystic fibrosis patients, we recommend annual oral glucose tolerance tests in all cystic fibrosis patients above the age of 10 years.     

Effect of the R569W missense mutation on the biosynthesis of myeloperoxidase

Human neutrophil microbicidal activity is largely mediated by reactive species generated by the oxygen-dependent myeloperoxidase (MPO) system. Peroxidase-negative neutrophils from many patients with hereditary MPO deficiency possess a 90-kDa MPO-related protein. We recently identified a missense mutation, R569W, in the MPO gene of many subjects with MPO deficiency. In these studies we examined the consequences of R569W on MPO biosynthesis and processing, using stably transfected K562 cells expressing normal MPO or the R569W mutation. K562 cells expressing normal MPO mimicked faithfully many features of MPO biosynthesis in myeloid cells. 1) apopro-MPO was synthesized; 2) a functional heme group was inserted into apopro-MPO, and enzymatically active pro-MPO was thereby generated; 3) pro-MPO underwent proteolytic processing to mature MPO; and 4) hemin augmented the processing of pro-MPO. pREP-R569W cells synthesized apopro-MPO, but heme was not inserted. Neither enzymatically active pro-MPO nor mature MPO was synthesized by transfectants expressing mutated cDNA, confirming our hypothesis that the R569W mutation results in a form of apopro-MPO which does not undergo post-translational processing to enzymatically active MPO species. In addition, these data support previous suggestions that heme insertion into apopro-MPO is necessary for its subsequent proteolytic processing into mature MPO subunits.     

Neonatal screening for cystic fibrosis: result of a pilot study using both immunoreactive trypsinogen and cystic fibrosis gene mutation analyses

We have evaluated a two-tier neonatal cystic fibrosis (CF) screening of immunoreactive trypsinogen (IRT) followed by CFTR gene mutation analysis using a systematic scanning of exons 7, 10, and 11, and, if necessary, by direct DNA sequencing. Over an 18-month period we screened 32,300 neonates born in the western part of Britanny. The first tier, involving IRT screening at 3 days of age, utilizes a low elevation of the trypsinogen level (600 ng/ml), which is highly sensitive. The second tier, which corresponds to the exhaustive screening for mutations in three exons of the gene, is highly specific for this population (Britanny). The false positive rate is very low, and no false negatives have been reported to date. This strategy has allowed the identification of five novel alleles (V322A, V317A, 1806 del A, R553G, G544S).     

Non-infectious pulmonary complications in cystic fibrosis in the adult

This paper reviews the logic of causal inference from epidemiological data. I maintain that the clearest causal statements can be made when the philosophical causal principles of association, direction and isolation are upheld in epidemiological research. After reviewing the argument by Holland that only experimental manipulation affords clear causal claims, I examine the utility of structural equation models and longitudinal methods for making causal claims from non-experimental data. This examination leads to the conclusion that mental health epidemiologists should begin to incorporate intervention trials into the last phases of their research programmes when they want to make strong causal claims.     

Exercise limitations and training for patients with cystic fibrosis

Exercise has much to offer to cystic fibrosis patients. Overcoming the limits of decreased pulmonary function by increasing fitness has a considerable potential to improve patients' quality of life; decreased breathlessness allows greater mobility and participation with peers in social and sporting activities, improves confidence and self-esteem and creates a greater pleasure in life for the individual patient. There are also immediate therapeutic gains and potentially long-term gains with improved survival. Above all, cystic fibrosis patients enjoy and prefer exercise as a therapeutic option to most other forms of therapy.     

Correlates of osteopenia in patients with cystic fibrosis

The responses to heat shock in Tritrichomonas mobilensis, a squirrel monkey parasite and Tritrichomonas augusta, an amphibian trichomonad, were evaluated by means of metabolic labeling with [35S]methionine. Electrophoretically separated trichomonad proteins synthesized at different temperatures were visualized by autoradiography and the label incorporation quantitated by a trichloroacetic acid precipitation procedure. A considerable difference in thermotolerance between the two species was found as the protein synthesis reached a maximum at 41 C in T. mobilensis and 37 C in T. augusta. The latter tolerated temperature increases 13 C above normal cultivation temperatures as compared to only 4 C thermotolerance range above normal in T. mobilensis. Major heat shock proteins (Hsps) were expressed in both T. mobilensis (with apparent Mr 94, 72, and 58 kDa) and T. augusta (Mr 94, 70, and 56 kDa) as revealed by autoradiography. Western blot analysis with polyclonal antibody against DnaK of Escherichia coli showed the presence of antigenic Hsp70 homologs in both trichomonads. Similarly, a polyclonal antibody against Hsp60 with broad interspecies cross-reactivity detected Hsp60 homologs in both T. mobilensis and T. augusta. The anti-DnaK antibody cross-reacted with a T. mobilensis protein localized in Golgi apparatus as demonstrated by immunoelectron microscopy. Immunocytochemistry on trichomonad frozen sections revealed the presence of the Hsp60 homolog in light-microscopic granules corresponding to hydrogenosomes.