Purinoceptor activation of chloride transport in cystic fibrosis and CFTR-transfected pancreatic cell lines

The regulation of chloride efflux from cystic fibrosis pancreatic adenocarcinoma cells (CFPAC-1) and wild-type CFTR-transfected CFPAC-1 cells (TPAC) was compared. Forskolin (10 microM) stimulated chloride efflux from the corrected TPAC cells but not from CFPAC-1 cells. Chloride efflux from both cell types was activated by thapsigargin (0.5 microM). The nucleotides ATP and UTP and the non-hydrolyzable ATP analogue, adenosine 5'-O-(3-thio) triphosphate (ATPgammaS), stimulated chloride efflux from both cell types. None of the other P2 purinoceptor agonists investigated elicited a response. The order of potency was ATP > or = UTP > or = ATPgammaS. Adenosine (10-100 microM) activated choride efflux from the TPAC but not the CFPAC cell line with no increase in intracellular cyclic AMP. Small but statistically significant inhibitions of the adenosine-(50 microM)-stimulated increase in chloride efflux were elicited by the A1 receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (CPX, 100 nM) and the A2 receptor antagonist 3,7-dimethyl-1-propylargylxanthine (DMPX, 10 microM). The A2A receptor antagonist 8-(3-chlorostyryl)caffeine (CSC, 100 nM) had no significant effect. These results provide evidence for the regulation of chloride efflux by P2Y2 purinoceptors in genetically-corrected and CF pancreatic cell lines. Studies with adenosine receptor antagonists indicate some possible involvement of A1 and A2 (but not A2A) receptors in the adenosine stimulation of chloride efflux, but the relatively small effects of the inhibitors coupled with lack of increase in cyclic AMP and a response only in the CFTR-transfected cells also suggests a possible direct effect of adenosine on CFTR.     

Effect of supplemental oxygen on supramaximal exercise performance and recovery in cystic fibrosis

The effects of supplemental O2 on recovery from supramaximal exercise and subsequent performance remain unknown. If recovery from exercise could be enhanced in individuals with chronic lung disease, subsequent supramaximal exercise performance could also be improved. Recovery from supramaximal exercise and subsequent supramaximal exercise performance were assessed after 10 min of breathing 100% O2 or room air (RA) in 17 cystic fibrosis (CF) patients [25 +/- 10 (SD) yr old, 53% men, forced expired volume in 1 s = 62 +/- 21% predicted] and 17 normal subjects (25 +/- 8 yr old, 59% men, forced expired volume in 1 s = 112 +/- 15% predicted). Supramaximal performance was assessed as the work of sustained bicycling at a load of 130% of the maximum load achieved during a graded maximal exercise. Peak minute ventilation (VE) and heart rate (HR) were lower in CF patients at the end of each supramaximal bout than in controls. In CF patients, single-exponential time decay constants indicated faster recovery of HR (tau HR = 86 +/- 8 and 73 +/- 6 s in RA and O2, respectively, P < 0.01). Similarly, fast and slow time constants of two-exponential equations providing the best fit for ventilatory recovery were improved in CF patients during O2 breathing (tau 1VE = 132.1 +/- 10.5 vs. 82.5 +/- 10.4 s; tau 2VE = 880.3 +/- 300.1 vs. 368.6 +/- 107.1 s, P < 0.01). However, no such improvements occurred in controls. Supramaximal performance after O2 improved in CF patients (109 +/- 6% of the 1st bout after O2 vs. 94 +/- 6% in RA, P < 0.01). O2 supplementation had no effect on subsequent performance in controls (97 +/- 3% in O2 vs. 93 +/- 3% in RA). We conclude that supplemental O2 after a short bout of supramaximal exercise accelerates recovery and preserves subsequent supramaximal performance in patients with CF.     

Effects of gravity on tracheal mucus transport rates in normal subjects and in patients with cystic fibrosis

A noninvasive, radionuclide imaging technique for measuring the rate of mucus clearance in the trachea (RT), was used to study gravitational effects on mucus clearance in 13 patients with cystic fibrosis (CF), average age 17 years; 7 normal, nonsmoking adults, average age 26 years; and a normal subject who was recovering from an acute upper respiratory tract infection (URTI). In the upright position, nine of the CF patients and the subject with URTI demonstrated abnormal tracheal mucus clearance which approached normal when they were placed in 25 degrees headdown position. The normal subjects and two of the CF patients showed no significant difference in the RT measured in the two positions. The results of the study indicate that the force of gravity can be a major influence on tracheal mucus clearance in CF and URTI subjects. This conclusion supports the use of postural drainage as an effective form of therapy in patients with cystic fibrosis.     

Effect of sinus surgery on pulmonary function in patients with cystic fibrosis

The rare case of neurilemmoma of the larynx was presented. The difficulties in histopathologic diagnosis of such tumors were emphasized. The tumor was removed by surgery from external approach.     

Effect of alcohol on exercise-induced changes in serum glucose and serum free fatty acids

Electrochemical measurements show that there are high-potential states of two copper proteins, Pseudomonas aeruginosa azurin and Thermus thermophilus CuA domain; these perturbed states are formed in guanidine hydrochloride (GuHCl) solution in which the proteins are still blue (azurin) and purple (CuA). In each case, the high-potential state forms reversibly. Absorption (azurin, CuA), visible circular dichroism (azurin, CuA), resonance-Raman (CuA), and EPR (CuA) spectra indicate that the structure of the oxidized copper site of each high-potential form is very similar to that of the native protein. It is proposed that GuHCl perturbs one or more H-bonds in the blue or purple copper active site, thereby allowing Cu(I) to adopt a more favorable coordination structure than that in the rigid cavity of the native protein.     

Effect of hypothyroidism on glucose transport and metabolism in rat small intestine

A cell line (SMKT-R3) established from human renal cell carcinoma was characterized for the presence of sulfolipids and glycolipid sulfotransferases. Sulfolipids were found to constitute a large part of the acidic glycolipid fraction in SMKT-R3 cells. These findings were confirmed by metabolic labelling with 35S-sulfate. These sulfolipids were expressed at the surface of SMKT-R3 cells as ascertained by cytofluorometry using a monoclonal antibody directed to sulfolipids. Furthermore, markedly high activity levels of glycolipid sulfotransferases were observed in SMKT-R3 cells compared with other cell lines. These results suggest that the increased synthesis of sulfolipids in renal cell carcinoma tissue (Sakakibara et al., 1989. Cancer Res., 49, 335-339) is due to the elevation of the sulfotransferase activities of renal carcinoma cells themselves.     

Effect of soleus unweighting on stimulation of insulin-independent glucose transport activity

Unweighting of the rat soleus by tail-cast suspension results in increased insulin action on stimulation of glucose transport, which can be explained, at least in part, by increased insulin binding and enhanced glucose transporter protein levels. Glucose transport is also activated by an insulin-independent mechanism stimulated by in vitro muscle contractions or hypoxia. Therefore, the purpose of this study was to determine if soleus unweighting leads to an enhanced response of the insulin-independent pathway for stimulation of glucose transport. The hindlimbs of juvenile male Wistar rats were suspended by a tail-cast system for 3 or 6 days. Glucose transport activity in isolated soleus strips (approximately 18 mg) was then assessed by using 2-deoxy-[1,2-3H]glucose (2-DG) uptake. Insulin (2 mU/ml) had a progressively enhanced effect on 2-DG uptake after 3 and 6 days of unweighting (+44 and +72% vs. control, respectively; both P < 0.001). At these same times, there was no difference between groups for activation of 2-DG uptake by maximally effective treatments with contractions (10 tetanuses), hypoxia (60 min), or caffeine (5 mM). These results indicate that the enhanced capacity for stimulation of glucose transport after soleus unweighting is restricted to the insulin pathway, with no apparent enhancement of the insulin-independent pathway.     

Animal studies of cystic fibrosis

Cystic fibrosis is the most common life-threatening autosomal recessive genetic disorder in Caucasian populations. It is a disease primarily of epithelial tissues, including the airway, pancreatic duct, intestine, genital tract and sweat glands. The affected gene was cloned and characterized in 1989. In the absence of an identified natural animal model of the disease, a major effort has been made to develop transgenic cystic fibrosis mice, by disrupting the gene in these laboratory animals. Such mice show many, but not all, of the symptoms of cystic fibrosis. In this article, the major past and present contributions of other animal systems to our understanding of cystic fibrosis are examined and their potential for future studies of this disease are discussed. It is intended to give the reader a broad overview of the field, exploring the usefulness of animal studies, rather than dealing more fully with specific aspects of cystic fibrosis.     

Atypical case of cystic fibrosis

A patient of cystic fibrosis is hereby reported. He had no family history and presented with chest symptoms, only. There was no evidence of hepatic or pancreatic involvement. To our knowledge this represents the first case of its kind from this part of country.     

Effect of cystic fibrosis-associated mutations in the fourth intracellular loop of cystic fibrosis transmembrane conductance regulator

The cystic fibrosis transmembrane conductance regulator (CFTR) contains multiple membrane spanning sequences that form a Cl- channel pore and cytosolic domains that control the opening and closing of the channel. The fourth intracellular loop (ICL4), which connects the tenth and eleventh transmembrane spans, has a primary sequence that is highly conserved across species, is the site of a preserved sequence motif in the ABC transporter family, and contains a relatively large number of missense mutations associated with cystic fibrosis (CF). To investigate the role of ICL4 in CFTR function and to learn how CF mutations in this region disrupt function, we studied several CF-associated ICL4 mutants. We found that most ICL4 mutants disrupted the biosynthetic processing of CFTR, although not as severely as the most common DeltaF508 mutation. The mutations had no discernible effect on the channel's pore properties; but some altered gating behavior, the response to increasing concentrations of ATP, and stimulation in response to pyrophosphate. These effects on activity were similar to those observed with mutations in the nucleotide-binding domains, suggesting that ICL4 might help couple activity of the nucleotide-binding domains to gating of the Cl- channel pore. The data also explain how these mutations cause a loss of CFTR function and suggest that some patients with mutations in ICL4 may have a milder clinical phenotype because they retain partial activity of CFTR at the cell membrane.     

Further purification and characterization of serum proteins used to detect cystic fibrosis genotypes by isoelectric focusing

Sera from cystic fibrosis (CF) homozygotes and obligate heterozygotes contain a CF factor (gamma CF factor) not found by isoelectric focusing in thin-layer polyacrylamide gels in most normal control sera. In addition, sera from most obligate heterozygotes lack another protein (bland B, C, or D) that is commonly found in sera from most normal and cystic fibrosis individuals. A standardized, biophysical assay is described that employs isoelectric focusing for the detection of both CF homozygotes and heterozygotes based on the analysis of whole serum for the presence of the gamma CF factor and bands B, C, and D. Results of analyzing sera from selected CF patients by isoelectric focusing indicated that there is a general correlation between the amount of the gamma CF factor and the clinical severity of the disease. Partial purification and characterization of the gamma CF factor and protein bands B, C, and D was accomplished by using DEAE-cellulose chromatography, Sephadex G-200 gel filtration, sequential molecular filtration through a series of Amicon Diaflo ultrafiltration membranes, affinity chromatography, and cellulose acetate electrophoresis. The gamma CF factor is a cationic protein with a pI of 8.46+/-0.05, has gamma electrophoretic mobility, a molecular weight between 3,500 and 10,000, and apparently exists in CF serum in 2 forms (free in solution and complexed to IgG). Bands B, C, and D are cationic proteins with pI values of 7.85 to 8.10, have gamma electrophoretic mobility and a molecular weight of approximately 100,000-150,000.     

Effect of increasing doses of hypertonic saline on mucociliary clearance in patients with cystic fibrosis

BACKGROUND: Patients with cystic fibrosis are known to have decreased mucociliary clearance. It has previously been shown that inhalation of a 7.0% solution of hypertonic saline significantly improved mucociliary clearance in a group of adult patients with cystic fibrosis. The aim of this study was to measure the response to increasing concentrations of inhaled hypertonic saline. METHODS: Ten patients (seven men) of mean (SE) age 22 (4) years and mean forced expiratory volume in one second (FEV1) 52.0 (6.7)% predicted completed the study. Mucociliary clearance was measured using a radioaerosol technique for 90 minutes after the interventions which comprised 0.9% NaCl + voluntary cough (control), 3.0% NaCl, 7.0% NaCl, and 12% NaCl. RESULTS: There was a significant increase in the amount of activity cleared from the right lung with all concentrations of hypertonic saline (HS) compared with control. The amount cleared at 90 minutes on the control day was 12.7% (95% confidence interval (CI) 9.8 to 17.2) compared with 19.7% (95% CI 13.6 to 29.5) for 3% HS, 23.8% (95% CI 15.9 to 36.7) for 7% HS and 26.0% (95% CI 19.8 to 35.9) for 12% HS. The improvement in mucociliary clearance was not solely due to coughing as the number of coughs recorded on the control day exceeded that recorded on any other day. The hypertonic saline did not induce a clinically significant change in FEV1. CONCLUSIONS: Within the range of concentrations examined in this study, the effect of hypertonic saline appears to be dose dependent. Inhalation of hypertonic saline remains a potentially useful treatment for patients with cystic fibrosis.     

Community-based care in cystic fibrosis: role of the cystic fibrosis nurse specialist and implications for patients and families

Improved survival for cystic fibrosis has rapidly increased over the past four decades, with patients now living well into adult life. With changes in the structure of the National Health Service and the formation of provider units and general practitioner (GP) fund-holding practices, it is important to strengthen links between the hospital and community teams to ensure that the CF patient receives adequate care. Increasingly, treatment is being carried out at home, and this emphasis on home-based therapy demands that parents/carers and patients must acquire the skills and knowledge of complex therapies in order to optimize health. It is the role of the CF nurse specialist (NS) to educate those who will deliver the care, co-ordinate the provision of services at home, liaise with the CF team and community health-care professionals and to support the patient and their carers.     

Parent relationships and compliance in cystic fibrosis

BACKGROUND: Olfactory dysfunction is one of the major complaints in patients suffering from allergic rhinitis. Little is known about the onset of hyposmia in seasonal allergy. METHODS: We performed two prospective studies to examine olfactory function in allergic rhinitis using an established (modified CCCRC) test for olfactory threshold, identification and discrimination. RESULTS: In a pilot study the time-course of olfactory function in 14 patients with allergic rhinitis to grass pollen was examined at the beginning of the season. Olfactory function was evaluated birhinal on day 3, 7, 14, and 21 of the season. Preseasonally, all patients were normosmic. There was a significant decrease in threshold and identification between the third and fourteenth day of the season, resulting in a moderate hyposmia in the mean. Hyposmia was not correlated to subjective symptom of nasal blockage. Therefore, a follow-up study was performed on 17 patients and a control group with a similar study design including measurements of nasal volume flow (rhinomanometry) and an inflammatory cell activation marker (ECP) in nasal secretions. The time-course of the olfactory changes was much better correlated to the inflammatory measure than to nasal volume flow. CONCLUSIONS: Patients with allergic rhinitis develop a significant olfactory dysfunction under allergen exposition. Inflammatory dysfunction of the olfactory epithelium seems to be more important than respiratory dysfunction in the pathomechanism of allergic hyposmia.