Rescue of CF airway epithelial cell function in vitro by a CFTR potentiator,VX-770

Cystic fibrosis (CF) is a fatal genetic disease caused by mutations in the gene encoding the CF transmembrane conductance regulator (CFTR), a protein kinase A (PKA)-activated epithelial anion channel involved in salt and fluid transport in multiple organs, including the lung. Most CF mutations either reduce the number of CFTR channels at the cell surface (e.g., synthesis or processing mutations) or impair channel function (e.g., gating or conductance mutations) or both. There are currently no approved therapies that target CFTR. Here we describe the in vitro pharmacology of VX-770, an orally bioavailable CFTR potentiator in clinical development for the treatment of CF. In recombinant cells VX-770 increased CFTR channel open probability (P_o) in both the F508del processing mutation and the G551D gating mutation. VX-770 also increased Cl⁻ secretion in cultured human CF bronchial epithelia (HBE) carrying the G551D gating mutation on one allele and the F508del processing mutation on the other allele by ≈10-fold, to ≈50% of that observed in HBE isolated from individuals without CF. Furthermore, VX-770 reduced excessive Na⁺ and fluid absorption to prevent dehydration of the apical surface and increased cilia beating in these epithelial cultures. These results support the hypothesis that pharmacological agents that restore or increase CFTR function can rescue epithelial cell function in human CF airway.     

Voriconazole pharmacokinetic variability in cystic fibrosis lung transplant patients

Background. Aspergillosis is a high‐risk complication in cystic fibrosis (CF) lung transplant patients. Azole antifungal drugs inhibit CYP3A4, resulting in significant metabolic drug–drug interactions. Voriconazole (VRZ) was marketed without therapeutic drug monitoring (TDM) recommendations, consistent with favorable pharmacokinetics, but regular determinations of plasma VRZ concentration were introduced in our center to manage interactions with calcineurin inhibitors and to document the achievement of therapeutic levels. Methods. VRZ TDM data analysis for trough concentration (C0) and peak concentration (C2) was carried out, using validated liquid chromatography assay with ultraviolet detection, for 35 CF lung transplant patients (mean age 25 years, mean weight 47 kg, balanced sex ratio) since 2003. Therapeutic range (C0: 1.5 ± 0.5 – C2 : 4.0 ± 1.0 mg/L) was expressed relative to pivotal pharmacokinetic trial data. Results. The duration of VRZ treatment ranged from 9 days to 22 months. The recommended standard dose of VRZ (200 mg twice a day, following the loading dose) resulted in significant plasma concentrations (>0.5 mg/L) in 20% of CF lung transplant patients. Therapeutic concentrations were obtained using higher doses (average 570 ± 160 mg/day, +43%, P<0.01). Despite adaptation, C0 remained <0.5 mg/L (11%), even when the drug was administered intravenously, highlighting the variability of VRZ pharmacokinetics, possibly enhanced by CYP2C19 polymorphism. The risk of inefficacy during periods of underdosage was overcome by treatment with antifungal drug combinations (caspofungin, n=10). The therapeutic index was limited by neurologic effects (14%) and hepatic abnormalities (30%). VRZ concentrations correlated significantly (P<0.01) with aspartate aminotransferase levels but not with bilirubin levels. VRZ acted as a metabolic inhibitor of tacrolimus (C0 to dose ratio 5.8 ± 2.6, n=31/VRZ versus 1.7 ± 0.9 alone, P<0.001). Large changes in azole concentration affected the magnitude of the drug–drug interactions and adjustment requirements. Conclusions. TDM is required because VRZ levels are often undetectable in treated CF lung transplant patients, supporting the use of antifungal drug combinations until achievement of VRZ C0 at a steady state between 1 and 2 mg/L. Plasma VRZ concentrations should be determined for the quantitative, individualized management of drug–drug interactions in lung transplant patients, in particular immunosuppressant such as tacrolimus, considering VRZ to be both a target and an inhibitor of CYP3A4.     

Clinical and pathological features of primary carcinoma of the cystic duct

Background

According to Farrar’s criteria, a tumor restricted to the cystic duct is defined as cystic duct carcinoma, but this definition excludes advanced carcinoma originating from the cystic duct.

Patients and methods

For the purpose of this study, primary cystic duct carcinoma was defined as a tumor originating from the cystic duct. We investigated the clinicopathological features of 15 cystic duct carcinomas, including 13 that did not fit Farrar’s criteria, and compared them with those of 52 cases of gallbladder carcinoma and 161 cases of extrahepatic bile duct carcinoma.

Results

The incidence of primary cystic duct carcinoma was 6.6% among all malignant biliary tumors. The main symptom was jaundice in 67% of cases. The operative procedures employed ranged from cholecystectomy to hepatopancreatoduodenectomy. The cases of cystic duct carcinoma and bile duct carcinoma showed a high frequency of perineural infiltration. The overall 5-year survival rate of the 15 patients was 40%.

Conclusion

Patients with advanced cystic duct carcinoma show a high frequency of jaundice and perineural infiltration. Our data suggest that cystic duct carcinoma may be considered a distinct subgroup of gallbladder carcinoma. Radical surgery is necessary for potentially curative resection in patients with advanced cystic duct carcinoma.     

Lung clearance index: Normal values,repeatability, and reproducibility in healthy children and adolescents

There is increasing interest in using the Multiple Breath Washout technique and the lung clearance index (LCI) for detecting early pulmonary changes, for example, in cystic fibrosis lung disease. However, there are still limited data regarding equipment specific reference ranges, repeatability and reproducibility. The aim of this prospective study was to assess within‐test repeatability, short term reproducibility and long term reproducibility, and to establish normal values for the LCI in healthy children and adolescents using the sidestream ultrasonic flow sensor (EasyOne Pro, MBW Module, ndd Medical Technologies, Switzerland). Fourty‐four volunteers (5.3–20.3 years) were recruited for the 1st test. Twenty‐two out of 44 were measured on a 2nd test occasion after an interval of 1 hr (2nd test). Thirty‐four out of 44 agreed to come back for a follow up test 6–15 months later (3rd test). Mean LCI (SD) was 6.2 (0.4), 6.3 (0.4), and 6.0 (0.4) at the 1st, 2nd, and 3rd test. The upper limit of normal was 7.0 for all subjects. Within‐test repeatability was 5.1%. Short‐term reproducibility (1st test vs. 2nd test) was 4.2% with a mean difference of ?0.13 (95% CI ?0.350; 0.087). Long‐term reproducibility (1st test vs. 3rd test) was 5.1%, with a mean difference of 0.017 (95% CI ?0.016; 0.348). With this low variability of the LCI for both, within and between tests, our study demonstrates reliability and robustness of equipment, protocol and analysis and the reliability of the MBW technique in general. The present data will help to interpret the effect of therapeutic interventions and interpretation of longitudinal data in patients with pulmonary diseases. Pediatr Pulmonol. 2009; 44:1180–1185. © 2009 Wiley‐Liss, Inc.     

Antibody response to Pseudomonas aeruginosa in children with cystic fibrosis

Cystic fibrosis (CF) is the most frequent life threatening autosomal recessive disease in white subjects. The primary cause of morbidity and mortality in children with CF is chronic pulmonary infection, mainly caused by Pseudomonas aeruginosa. The purpose of this study was to assess the value of the measurement of antibodies to P. aeruginosa in diagnosing lung infection by the bacteria in CF patients. We assessed P. aeruginosa antibody titers in CF patients from Rio de Janeiro, Brazil, using cell lysate antigens as well as recombinant PcrV, a Type III Secretion System protein. Sputum (more than 70% of the specimens) or oropharyngeal swabs were obtained whenever patients were regularly followed for their pulmonary disease. Blood samples were obtained with an average interval of 6 months for a period of 2 years. The ELISA cut‐offs were assigned as the positive 95% confidence interval of the mean antibody levels from non‐fibrocystic controls. Our data showed that most CF patients (81%) of whom were not chronically infected by P. aeruginosa (Groups I and II), had their first serology positive for rPcrV. Cell‐lysate ELISA was able to detect P. aeruginosa antibodies before positive culture in the first serum sample of 44% of the patients from Groups I and II. When serum reactivity to rPcrV and cell lysate were combined, 94% of CF patients from Groups I and II (n = 16) had the first serology positive for P. aeruginosa over a mean time of 20 months before the first isolation of P. aeruginosa. In conclusion, longitudinal P. aeruginosa serology should become part of respiratory care follow‐up, in conjunction with other lung parameter functions. Pediatr Pulmonol. 2009; 44:392–401. © 2009 Wiley‐Liss, Inc.     

Nocturnal hypoxia and sleep disturbances in cystic fibrosis

Disrupted sleep and nocturnal hypoxia are common in cystic fibrosis (CF). However, the predictors of nocturnal hypoxia in CF are still controversial. In order to identify the risk factors for nocturnal desaturation and sleep disturbances, we carried out a clinical and polysomnographic investigation of CF patients. We studied 30 clinically stable CF cases with clinical lung disease (mean age = 12.8; mean FEV1 = 65.2), 10 CF cases without significant lung disease (mean age = 13.3; mean FEV1 = 99.8), and 20 controls (mean age = 15.5). Patients were evaluated by spirometry, 6‐min walk test, the Shwachman–Kulczycki (S–K) score, and full overnight polysomnography. Cases with clinical lung disease had lower body mass index, forced vital capacity, and S–K scores. During sleep, five CF cases with clinical lung disease (15%) had SaO₂ <90% during more than 30% of total sleep time and 11 cases (36.6%) had a nadir SaO₂ below 85%. FEV1 values for CF cases with clinical lung disease were related to nadir SaO₂ (P < 0.03) and to mean SaO₂ (P = 0.02). A receiver operating characteristic (ROC) analysis determined FEV1 at 64% to be predictive of nocturnal desaturation as defined by minimum SaO₂ <85% (sensitivity = 92.3%; specificity = 77.3%) or SaO₂ <90% for 30% of sleep time (sensitivity = 81.8%; specificity = 85.2%). Frequency of impaired sleep was not different in CF cases with (N = 2) and without significant lung disease (N = 5, P = 0.53). Sleep architecture was not significantly different between the two groups. Sleep apnea was present in three CF cases with clinical lung disease and in one case without significant lung disease. In summary, desaturation during sleep can be predicted by FEV1 <64% with good sensitivity and specificity. There are no significant differences in sleep architecture between clinically stable CF cases with and without significant lung disease. Pediatr Pulmonol. 2009; 44:1143–1150. ©2009 Wiley‐Liss, Inc.     

误诊为脑囊虫病的颅内畸胎瘤1例

本文报道了1例颅内畸胎瘤病例。患者曾被误诊为脑囊虫病,经2个疗程诊断性抗囊虫治疗无效后行手术治疗,最终经病理诊断为颅内畸胎瘤。