Involvement In Cystic Fibrosis Research Articles

Characterization of LasR protein involved in bacterial quorum sensing mechanism of Pseudomonas aeruginosa

The quorum sensing (QS) mechanism of Pseudomonas aeruginosa has been studied extensively due to its involvement in cystic fibrosis, a deadly disease that is responsible for the death of more than a thousand people annually. In order to develop biochemical assay method for screening QS inhibitor, we have studied the production and characterization of recombinant LasR protein, which is a transcriptional activator for the QS mechanism in P. aeruginosa. In recombinant Escherichia coli BL21, LasR was produced as functionally-active proteins when the cells were cultivated in the presence of a proper signaling molecule (acyl homoserine lactone, AHL) only. Some soluble LasR proteins could be obtained from the cells which were grown in AHL-deficient medium, but they did not show binding affinity to the promoter sequence OP1 (lasB elastase promoter). Furthermore, the active LasR, presumably produced as LasR-AHL complex, was not dissociated into its components (LasR and AHLs) in vitro. The current results indicate that the production of pure and active LasR devoid of AHL is very difficult. It can be concluded that the development of biochemical assay method for screening AHL competitive inhibitors which requires pure and active LasR proteins might not be possible unless the structure of LasR and/or its folding processes is modified.

Liver involvement in cystic fibrosis

The hepatobiliary manifestations of cystic fibrosis (CF) encompass a broad clinical spectrum, from mild steatosis, associated with poor nutrition, to multilobular cirrhosis and the complications of portal hypertension. The factor(s) responsible for the development and progression of liver disease in a subset of patients with CF are unknown. Liver disease can be silent and progressive, manifesting only with complications associated with cirrhosis and portal hypertension. Clinical evaluation for detecting and monitoring the progression of liver disease includes the following: physical examination of the liver, biochemical tests of liver function and injury, and radiological imaging with abdominal ultrasonography. Careful monitoring should take place in all patients with CF, as currently, there are no sensitive and/or specific historical or biochemical markers to predict who is at risk for the development of liver disease. Current treatment options for CF-associated liver disease are very limited. The bile acid ursodeoxycholic acid may improve biochemical parameters of liver disease, but its long-term efficacy in preventing the progression of liver disease in CF is unproven. Treatment therefore rests on optimizing nutritional status; correcting fat-soluble vitamin, essential fatty acid, and other mineral deficiencies; and treating complications of end-stage liver disease, such as pruritus, ascites, and portal hypertension.

Liver Disease in Cystic Fibrosis

Liver involvement in Cystic Fibrosis (CF) is much less frequent than both pulmonary and pancreatic diseases that are present in 80-90% of CF patients; liver disease (LD) affects only one third of CF patients, however, because of the decreasing mortality from extrahepatic causes, its recognition and management is becoming a relevant clinical issue. Recent observations suggest that clinical expression of LD in CF may be influenced by genetic modifiers; their identification is an important issue because it may allow recognition of patients at risk for the development of LD at the time of diagnosis of CF and early institution of prophylactic strategies. Oral bile acid therapy, aimed at improving biliary secretion in terms of bile viscosity and bile acid composition, is currently the only available therapeutic approach for CF-associated LD. However, the impact of this therapy on the natural history of LD remains to be defined and long-term effectiveness on clinically relevant outcomes should be further investigated. Liver transplantation should be offered to CF patients with progressive liver failure and/or with life-threatening sequelae of portal hypertension, who also have mild pulmonary involvement that is expected to support long-term survival. The 1-year survival rate after transplantation in CF patients is approximately 80%, with beneficial effects on lung function, nutritional status, body composition and quality of life in most cases.

Sinus and Mastoid Involvement in Cystic Fibrosis and the Efficacy of Surgical Intervention

Sinus and Mastoid Involvement in Cystic Fibrosis and the Efficacy of Surgical Intervention

232 Is there a correlation between pseudo-Bartter syndrome and pulmonary involvement in Cystic Fibrosis?

232 Is there a correlation between pseudo-Bartter syndrome and pulmonary involvement in Cystic Fibrosis?

Analyses of Pseudomonas aeruginosa Lectin Binding to α-Galactosylated Glycans

The specificity and binding capacity of the galactophilic lectin from the Gram negative bacterium Pseudomonas aeruginosa (PA-IL) was determined by solid phase measurements using galactosylated neoglycoproteins immobilized on microtiter plates. The bacterial lectin reacted with both short chain (monosaccharide) and long chain (pentasaccharide) glycoconjugates. Among the Galalpha1-XGal disaccharides, the highest affinity was observed towards the Galalpha1-3Gal structure. Raising the incubation temperature enhanced the lectin-polysaccharide agglutination, and it is suggested that binding to certain conformations of polysaccharides could vary between lectins with the same monocarbohydrate specificity and that this activity may, in part, be temperature dependent. Histochemical examination of lectin binding to different porcine tissues suggests a differential glycosylation of the carbohydrate antigens on endothelial cells in various parts of the vascular system. In the pancreas, PA-IL also adhered to the excretory ducts. These observations on PA-IL binding could be of importance both to determine infection foci in P. aeruginosa-mediated vacuities and to determine its role for pancreatic involvement in cystic fibrosis.

Pancreatic Cystosis in Children and Young Adults with Cystic Fibrosis: Sonographic, CT, and MRI Findings

We sought to analyze the sonographic, CT, and MRI findings of pancreatic cystosis, an unusual form of pancreatic involvement in cystic fibrosis (CF) that is characterized by macrocysts of different sizes distributed throughout the gland. CT and MRI essentially confirmed the findings of sonography in all cases, providing no relevant additional information about the nature, internal structure, or content of the cysts. When pancreatic macrocysts are clearly shown on sonography in asymptomatic patients with CF, no additional imaging is warranted.

Evidence of early lung involvement in CF

Brody and colleagues studied chest high-resolution computerized tomography (HRCT) in cystic fibrosis (CF) patients with mild to moderate chest disease and relatively normal pulmonary function tests. The investigators identified a high incidence of regional bronchiectasis, air trapping, and mucous plugging in otherwise normal appearing lungs (Figure). These findings demonstrate that HRCT is a sensitive tool that will be valuable in understanding the natural history of this disease. In the accompanying editorial, McColley points out how these findings can be used in clinical trials that seek to alter the course of lung disease in its earliest stages.Page 6 (editorial)Page 32 (article) Brody and colleagues studied chest high-resolution computerized tomography (HRCT) in cystic fibrosis (CF) patients with mild to moderate chest disease and relatively normal pulmonary function tests. The investigators identified a high incidence of regional bronchiectasis, air trapping, and mucous plugging in otherwise normal appearing lungs (Figure). These findings demonstrate that HRCT is a sensitive tool that will be valuable in understanding the natural history of this disease. In the accompanying editorial, McColley points out how these findings can be used in clinical trials that seek to alter the course of lung disease in its earliest stages. Page 6 (editorial) Page 32 (article)

Hepatobiliary complications of cystic fibrosis.

Cystic fibrosis (CF) is the most common potentially lethal genetic disease in the Caucasian population. The disease results from mutations in the gene for the cystic fibrosis transmembrane conductance regulator (CFTR), a cAMP-activated Cl(-) channel in the apical membrane of most secretory epithelia. In the liver, CFTR is located in biliary epithelial cells or cholangiocytes and gallbladder epithelia, where it appears to play a role in normal bile formation. However, how a defective CFTR protein leads to associated liver and biliary disease in a subset of patients with CF is unknown. Improvements in life expectancy have led to an increasing recognition of hepatobiliary complications from CF. Whereas the biliary tract disease is usually clinically evident, the liver involvement may progress silently, only manifesting as end-stage liver disease and portal hypertension. Unlike the pancreatic involvement in CF, a genotype-phenotype correlation is not apparent in the expression of liver disease, suggesting the presence of as yet unidentifiable "genetic modifiers" influencing disease expression. This review focuses on the pathogenesis, clinical manifestations, screening, diagnosis, and treatment of CF hepatobiliary disease.

Ultrasound Evaluation of Liver Disease in Cystic Fibrosis as Part of an Annual Assessment Clinic: A 9-year Review

AIM: To review 9 years of annual assessment data in cystic fibrosis (CF) and evaluate the frequency of hepatobiliary abnormalities and the correlation between ultrasound and biochemical findings. MATERIALS AND METHODS: Over a 9-year period (1990–99), 168 children (age range 1–18 years) with CF have undergone an annual assessment which has included clinical, biochemical and ultrasonographic evaluation of the hepatobiliary system. We have retrospectively reviewed the sequential ultrasound reports and correlated them with the contemporaneous biochemical results. RESULTS: A total of 725 ultrasound examinations were performed over the review period. Sixty patients had at least one examination showing an abnormality of liver echo texture and in 39 patients this was a persisting finding. Seven patients (4.2%) developed frank cirrhotic change on ultrasound criteria, while 15 patients (8.9%) had evidence of persistent splenomegaly. Gall-bladder calculi were present in 4.8%. In 176 examinations (24%) there was disparity between the ultrasound findings and aspartate aminotransferase (AST) levels. In 3.0% of cases (five patients) there were persisting abnormalities of liver echo texure and persisting splenomegaly with a normal range AST value. CONCLUSION: No perfect method of assessing hepatobiliary involvement in CF is currently available. Ultrasonographic and biochemical assessment may reflect different aspects of disease progression. Routine use of ultrasound in annual assessment allows identification of a minority of patients with liver changes but with normal biochemistry. Williams, S. M. et al. (2002) Clinical Radiology57, 365–370.

895 Paranasal sinus involvement in cystic fibrosis

895 Paranasal sinus involvement in cystic fibrosis

Long term follow up of changes in FEV1 and treatment intensity during Pseudomonas aeruginosacolonisation in patients with cystic fibrosis

BACKGROUNDColonisation with Pseudomonas aeruginosa (PA) is a striking feature of lung involvement in cystic fibrosis. To identify the clinical consequences of the different steps of colonisation with PA under a...

Ursodeoxycholic acid in cystic fibrosis-related liver disease: a systematic review.

Treatment of progressive lung disease in cystic fibrosis (CF) has improved greatly over the last 30 years, leading to improvement in survival well into adult lifel. This has led to clinicians paying increasing attention to both treating and delaying progression of disease in other affected organs. A recent epidemiological study2 reported that the clinical prevalence of cystic fibrosis-related liver disease is relatively uncommon in young children but rises to a peak in adolescence. The pathogenesis of liver involvement in CF remains unclear, partly because there are still insufficient long-term data on large numbers of patients. The end point seen at post-mortem is focal biliary cirrhosis which is the typical histological lesion found in those CF patients with liver disease and is characterized by portal ducts containing an inspissated granular eosinophilic material, bile duct proliferation, chronic inflammatory infiltration and some fibrosis3. This may progress to multilobular cirrhosis which has a reported incidence of up to 4% in one clinic4. Periportal changes were also seen with excessive mucus in the biliary tract3. These observations led to the suggestion that the development of focal biliary cirrhosis may be related to mucus obstruction in the intrahepatic ducts3 but this remains uncertain. Recently, the cystic fibrosis transmembrane regulator (CFTR) was found to be located at or near the apical membrane of the intrahepatic bile duct epithelium5. This observation has been followed by a hypothesis that a primary defect in biliary chloride transport may cause abnormal bile flow and thus contribute to the pathophysiology. In CF the faecal losses of bile acids and taurine (a bile acid conjugate) are high, resulting in a greater proportion of glycine-conjugated bile acids which are potentially more hepatotoxic than taurine-conjugated bile acids and may contribute to the bile duct injury6. It is likely that these mechanisms may lead eventually to intrahepatic bile duct irregularities seen at endoscopic retrograde cholangiography7 and to the observed post-mortem findings of CF liver disease. No association between genotype and development of liver disease has been found so far. A recent study analysing the risk factors for the development of liver disease associated with CF showed no difference in allele frequencies between those with and those without liver involvement8. Early detection and assessment of progression of CFliver disease can be difficult. By the time clinical liver disease is evident, usually portal hypertension and cirrhosis have already developed. At this stage, the only potentially curative treatment may be liver transplantation9. Biochemical markers of liver function may not be useful in the assessment of liver involvement because any hepatocyte dysfunction is due to the secondary effect of the primary intrahepatic ductal lesion and the level of abnormality does not always correlate with clinical evidence of liver disease6. Abnormalities of these tests may also be due to an effect other than CF liver disease such as an adverse effect of a drug treatment or bacterial infectionl. Ultrasound appearances of liver size and irregular texture, as well as Doppler studies of altered direction and velocity of portal vein flow can be used to assess the presence and progression of liver disease or portal hypertension1 1. A recent study has suggested that measuring biliary excretion of disopropylphenyl-carboxymethyl iminodiacetic acid (DISIDA) by radioisotope scanning with hepatic scintigraphy may be useful in assessing early liver involvement12. Recent developments in therapy have been directed towards attempting to improve biliary secretion and bile acid composition. Ursodeoxycholic acid (UDCA) is a naturally occurring hydrophilic bile acid which constitutes less than 4% of the total bile acid pool. In 1990, Erlinger et al. 13 showed that UDCA improves bile acid flow by inducing an increased bicarbonate-rich bile flow. Hydrophilic UDCA is less hepatotoxic than primary bile acids10. Initially UDCA was used to dissolve gallstones but more recently has been used as a possible treatment for other adult chronic cholestatic liver diseases such as primary biliary cirrhosis14 and primary sclerosing cholangitis1 . Following these trials, UDCA was found to improve liver function tests in CF liver disease16 and has since been used in the treatment of and hopefully in the prevention of progressive liver disease in CF in recent years. 6 'Respiratory Unit, Alder Hey Children's Hospital, Eaton Road, Liverpool L12 2AP; 2Department of Mathematical Sciences, University of Liverpool L69 3BX, England

Colonic wall thickness measured by ultrasound: striking differences in patients with cystic fibrosis versus healthy controls.

Colonic strictures represent an advanced stage of fibrosing colonopathy in patients with cystic fibrosis. To clarify whether ultrasonography can identify patients with an early stage of fibrosing colonopathy and to determine clinical factors that influence bowel wall thickening. Ninety patients with cystic fibrosis, median age 10 years, and 46 healthy controls, median age 13 years, were investigated. Bowel wall thickness was measured by ultrasound in a prospective study. In cystic fibrosis, wall thickness of both small intestine and colon was significantly (p < 0.0001) higher than in controls; 81% of patients with cystic fibrosis had a maximum colon wall thickness at any site of 2 mm or more, a value that was never reached by controls. The maximum colon wall thickness was 6.5 mm. Bowel wall thickness was unchanged at re-examination after one year. There was no progression even with high dose pancreatic supplements. There was no association between bowel wall thickness and clinical features such as previous meconium ileus, intestinal resection, distal intestinal obstruction syndrome, abdominal pain, or pancreatic enzyme dose. There is genuine intestinal involvement in cystic fibrosis; in a few cases this could lead to fibrosing colonopathy.

The role of hepatobiliary scintigraphy in cystic fibrosis

This was a prospective open study that examined the quantitative and qualitative analysis of hepatobiliary scintigraphy (DISIDA) in detecting liver involvement in cystic fibrosis (CF). Forty-four adult and pediatric patients (median age, 12.1 years; range, 1.1-36.3 years) were divided into three groups: group 1, no evidence of liver involvement (n = 8); group 2, biochemical evidence of liver involvement on two or more occasions (n = 26); and group 3, clinical evidence of liver disease (n = 10). In groups 1 and 2, the most common qualitative scintigraphic finding was focal intrahepatic retention of tracer (26/34 patients, 12 of whom had normal findings on ultrasonography). This finding corresponds to focal cholestasis and may warrant treatment with the choleretic agent ursodeoxycholic acid (UDCA). In the group 3 patients, the abnormal qualitative scintigraphic appearances (heterogeneous uptake of tracer and nodular liver outline) added little to the findings on ultrasonography; however, these patients had a prolonged mean hepatic clearance time compared with those in groups 1 and 2 (one-way ANOVA; P < .015). It is proposed that scintigraphy with DISIDA has a role in the detection of early liver involvement in cystic fibrosis.

The role of hepatobiliary scintigraphy in cystic fibrosis

This was a prospective open study that examined the quantitative and qualitative analysis of hepatobiliary scintigraphy (DISIDA) in detecting liver involvement in cystic fibrosis (CF). Forty-four adult and pediatric patients (median age, 12.1 years; range, 1.1-36.3 years) were divided into three groups: group 1, no evidence of liver involvement (n = 8); group 2, biochemical evidence of liver involvement on two or more occasions (n = 26); and group 3, clinical evidence of liver disease (n = 10). In groups 1 and 2, the most common qualitative scintigraphic finding was focal intrahepatic retention of tracer (26/34 patients, 12 of whom had normal findings on ultrasonography). This finding corresponds to focal cholestasis and may warrant treatment with the choleretic agent ursodeoxycholic acid (UDCA). In the group 3 patients, the abnormal qualitative scintigraphic appearances (heterogeneous uptake of tracer and nodular liver outline) added little to the findings on ultrasonography; however, these patients had a prolonged mean hepatic clearance time compared with those in groups 1 and 2 (one-way ANOVA; P < .015). It is proposed that scintigraphy with DISIDA has a role in the detection of early liver involvement in cystic fibrosis. (Hepatology 1996 Feb;23(2):281-7)

An ultrasound scoring system for the diagnosis of liver disease in cystic fibrosis

Advances in the management of the pulmonary complications of cystic fibrosis may result in an increasing prevalence of patients with chronic liver disease which may, therefore, become more important in the long-term management of cystic fibrosis patients. However, no simple and reliable test is available for the diagnosis of liver disease in cystic fibrosis. In particular percutaneous liver biopsy is highly inacurrate and potentially dangerous. Imaging techniques, including real-time ultrasound scanning, have been used to evaluate the hepato-biliary system in cystic fibrosis and may represent the best available techniques for documenting hepatic involvement. The purposes of this study were to construct an ultrasound scoring system using three cardinal features of hepatic ultrasound in cystic fibrosis: coarseness of the parenchyma, nodularity of the liver edge and increased periportal echogenecity, to enable the accurate, early diagnosis of liver involvement in cystic fibrosis. The scoring system was validated by correlating the results against ultrasound markers of portal hypertension, clinical and haemotological data. The scoring system proved to be reproducible and to correlate well with the markers of hepatic disease detailed above. The results also suggest that the scoring system may allow the identification of patients with pre-cirrhotic chronic liver disease and so may prove of value in selecting a sub-group of patients more likely to respond to therapy.

Method for rapid evaluation of topically applied agents to cystic fibrosis airways

The proposal is to target a single maxillary sinus for treatment with agents designed to reverse or ameliorate the cystic fibrosis (CF) defect in airway mucosa, with the opposite sinus serving as a control. Selected CF patients have undergone maxillary antrostomy and antibiotic lavage to help relieve severe pulmonary disease and chronically impacted and infected sinuses. After treatment, the mucosa in the maxillary sinuses of these patients are accessible and can be bathed with fluids introduced via the stomas with procedures that restrict the fluid to a single sinus. The ability of an agent to reverse mucosal pathology can therefore be determined easily with the mucosa of the contralateral sinus serving as a control. Electrophysiological properties, amounts and composition of fluid and mucus, immune functions, and bacterial colonization can be measured accurately and repeatedly. The consistent observation that sinus involvement in CF is near universal and bilaterally symmetric offers a unique opportunity for a simultaneous within-subject, double-blinded control paradigm. This approach should speed evaluation of any agent designed to improve airway mucosal function.

Relationships between essential fatty acid levels, pulmonary function and fat absorption in pre-adolescent cystic fibrosis children with good clinical scores.

Twenty-one pre-adolescent cystic fibrosis (CF) children with good clinical scores had significant (P less than 0.001) deficiencies of arachidonic (mean 3.8% of total plasma fatty acids +/- SD 1.4) and linoleic (18.1 +/- 6.3) acids compared with controls (6.0 +/- 1.0, and 27.6 +/- 3.9, respectively). Despite the presence of pulmonary involvement of varying severity in all the CF children, neither arachidonic nor linoleic acid levels correlated significantly with pulmonary function measured by spirometry. All children had adequate caloric and fat intakes, and the coefficient of fat absorption correlated with none of the deficient fatty acid levels. These findings suggest that deficiencies of arachidonic and linoleic acids are of minor importance in the early development of pulmonary involvement in CF, and that factors other than fat malabsorption and decreased dietary intake probably contribute to fatty acid deficiency.

The distinctly visible right upper lobe bronchus on the lateral chest: A clue to adolescent cystic fibrosis

Radiographic differentiation between cystic fibrosis and asthma presenting in teenagers and young adults can be difficult. Many patients with a late presentation of cystic fibrosis display minimal changes on a chest radiograph. However, a large majority (90%) of cystic fibrosis patients with an essentially normal PA chest radiograph will have a distinctly outlined orifice of right upper lobe bronchus on a lateral chest film as opposed to a small number of asthmatics (25%) or normal patients (18%). This observation correlates well with the pathologic finding that the initial pulmonary involvement in cystic fibrosis is typically in the right upper lobe in adolescents. Teenage or young adult patients presenting with a history of repeated respiratory infections, asthma-like symptoms and a distinctly visible right upper lobe bronchus on a lateral chest film should be sweat-tested to exclude cystic fibrosis.