Safety and efficacy of the epithelial sodium channel blocker idrevloride in people with primary ciliary dyskinesia (CLEAN-PCD): a multinational, phase 2, randomised, double-blind, placebo-controlled crossover trial

BACKGROUND

Mucociliary clearance is dysfunctional in people with primary ciliary dyskinesia, resulting in the accumulation of dehydrated mucus in the airways that is difficult to clear. We undertook a study to assess the benefit on lung function of treatment with a nebulised epithelial sodium channel (ENaC) blocker, idrevloride, with or without hypertonic saline, in people with primary ciliary dyskinesia.

METHODS

The CLEAN-PCD trial was a phase 2, randomised, double-blind, placebo-controlled crossover trial conducted at 32 tertiary adult and paediatric care centres and university hospitals in Canada, Denmark, Germany, Italy, the Netherlands, Poland, the UK, and the USA. People with a confirmed diagnosis of primary ciliary dyskinesia, aged 12 years or older, with a percentage of predicted FEV1 (ppFEV1) in the range of 40% to <90%, were randomly assigned in a 2:2:1:1 ratio (block size=6), stratified by ppFEV1 at screening, to one of four sequences: (1) idrevloride in hypertonic saline in treatment period 1 then hypertonic saline in treatment period 2; (2) hypertonic saline in treatment period 1 then idrevloride in hypertonic saline in treatment period 2; (3) idrevloride in treatment period 1 then placebo in treatment period 2; and (4) placebo in treatment period 1 then idrevloride in treatment period 2. The idrevloride dose was 85 μg and hypertonic saline was 4·2% NaCl. 3 mL of each study treatment was nebulised twice daily for 28 days in treatment periods 1 and 2; the two 28-day treatment periods were separated by a 28-day washout period. The primary endpoint was absolute change from baseline in ppFEV1 after 28 days. Safety assessments and reports of adverse events were made at clinic visits during each treatment period and by a follow-up telephone call 28 days after the last dose of study drug. Additionally, adverse events could be reported at a follow-up telephone call 3 days after the start of dosing and as they arose. Participants who received at least one dose of study drug were included in the safety analyses (safety set), and those who also had spirometry data were included in the efficacy analyses (full analysis set). The completed study is registered (EudraCT 2015-004917-26; ClinicalTrials.govNCT02871778).

FINDINGS

Between Sep 14, 2016, and May 31, 2018, 216 patients were screened and 123 were randomly assigned to one of four crossover sequences. Across the two treatment periods, treatment with idrevloride in hypertonic saline was initiated in 80 patients and completed in 78 patients (all 78 had data available and were included in the analysis); hypertonic saline initiated in 81 patients and completed in 76 patients (75 had data available and were included in the analysis); idrevloride initiated in 37 patients and completed in 35 patients (34 had data available and were included in the analysis); and placebo initiated in 36 patients and completed in 34 patients (all 34 had data available and were included in the analysis). Greater absolute increases in ppFEV1 from baseline to 28 days of treatment were seen with idrevloride in hypertonic saline (least-squares mean absolute change from baseline 1·0 percentage points, 95% CI -0·4 to 2·4) than with hypertonic saline alone (least-squares mean absolute change from baseline of -0·5 percentage points, -2·0 to 0·9; difference 1·5 percentage points, 95% CI <0·1 to 3·0; p=0·044). There was no significant difference in ppFEV1 for the parallel comparison of idrevloride in hypertonic saline compared with placebo or the crossover comparison of idrevloride with placebo. Adverse events were similar across treatments (57 to 65% of patients). Cough occurred in a greater proportion of participants during treatments that contained idrevloride or hypertonic saline compared with placebo, and oropharyngeal pain occurred in a greater proportion of participants during idrevloride treatments than during treatment with hypertonic saline alone or placebo, whereas chest discomfort was more common during treatments that included hypertonic saline.

INTERPRETATION

In this phase 2 crossover study, idrevloride in hypertonic saline was safe and associated with improved lung function over a 28-day period in people with primary ciliary dyskinesia compared with hypertonic saline alone. Larger, longer clinical studies are warranted to explore the potential benefits of idrevloride in combination with hypertonic saline in people with primary ciliary dyskinesia.

FUNDING

Parion Sciences, under agreement with Vertex Pharmaceuticals.

Situs Ambiguus Is Associated With Adverse Clinical Outcomes in Children With Primary Ciliary Dyskinesia

BACKGROUND

Primary ciliary dyskinesia (PCD) is a rare disorder of motile cilia associated with situs abnormalities. At least 12% of patients with PCD have situs ambiguus (SA), including organ laterality defects falling outside normal arrangement (situs solitus [SS]) or mirror image inversion (situs inversus totalis [SIT]).

RESEARCH QUESTION

Do patients with PCD and SA achieve worse clinical outcomes compared with those with SS or SIT?

STUDY DESIGN AND METHODS

This cross-sectional, multicenter study evaluated participants aged 21 years or younger with PCD. Participants were classified as having SA, including heterotaxy, or not having SA (SS or SIT). Markers of disease severity were compared between situs groups, adjusting for age at enrollment and severe CCDC39 or CCDC40 genotype, using generalized linear models and logistic and Poisson regression.

RESULTS

In 397 participants with PCD (mean age, 8.4 years; range, 0.1-21), 42 patients were classified as having SA, including 16 patients (38%) with complex cardiovascular malformations or atrial isomerism, 13 patients (31%) with simple CVM, and 13 patients (31%) without cardiovascular malformations. Of these, 15 patients (36%) underwent cardiac surgery, 24 patients (57%) showed an anatomic spleen abnormality, and seven patients (17%) showed both. The remaining 355 participants did not have SA, including 152 with SIT and 203 with SS. Overall, 70 participants (17%) harbored the severe CCDC39 or CCDC40 genotype. Compared with participants without SA, those with SA showed lower median BMI z scores (P = .03), lower FVC z scores (P = .01), and more hospitalizations and IV antibiotic courses for acute respiratory infections during the 5 years before enrollment (P < .01). Participants with cardiovascular malformations requiring surgery or with anatomic spleen abnormalities showed lower median BMI z scores and more hospitalizations and IV therapies for respiratory illnesses compared with participants without SA.

INTERPRETATION

Children with PCD and SA achieve worse nutritional and pulmonary outcomes with more hospitalizations for acute respiratory illnesses than those with SS or SIT combined. Poor nutrition and increased hospitalizations for respiratory infections in participants with SA and PCD are associated with cardiovascular malformations requiring cardiac surgery, splenic anomalies, or both.

TRIAL REGISTRY

ClinicalTrials.gov; Nos.: NCT02389049 and NCT00323167; URL: www.

CLINICALTRIALS

gov.

A Novel Homozygous Mutation Causing Complete TYK2 Deficiency, with Severe Respiratory Viral Infections, EBV-Driven Lymphoma, and Jamestown Canyon Viral Encephalitis

Autosomal recessive tyrosine kinase 2 (TYK2) deficiency is characterized by susceptibility to mycobacterial and viral infections. Here, we report a 4-year-old female with severe respiratory viral infections, EBV-driven Burkitt-like lymphoma, and infection with the neurotropic Jamestown Canyon virus. A novel, homozygous c.745C > T (p.R249*) variant was found in TYK2. The deleterious effects of the TYK2 lesion were confirmed by immunoblotting; by evaluating functional responses to IFN-α/β, IL-10, and IL-23; and by assessing its scaffolding effect on the cell surface expression of cytokine receptor subunits. The effects of the mutation could not be pharmacologically circumvented in vitro, suggesting that alternative modalities, such as hematopoietic stem cell transplantation or gene therapy, may be needed. We characterize the first patient from Canada with a novel homozygous mutation in TYK2.

Deletions in DNAL1 Cause Primary Ciliary Dyskinesia Across North American Indigenous Populations

We report 4 cases of primary ciliary dyskinesia in unrelated indigenous North American children caused by identical, homozygous, likely pathogenic deletions in the DNAL1 gene. These shared DNAL1 deletions among dispersed indigenous populations suggest that primary ciliary dyskinesia accounts for more lung disease with bronchiectasis than previously recognized in indigenous North Americans.

First reports of primary ciliary dyskinesia caused by a shared DNAH11 allele in Canadian Inuit

BACKGROUND

Primary ciliary dyskinesia (PCD) is typically an autosomal recessive disease characterized by recurrent infections of the lower respiratory tract, frequent and severe otitis media, chronic rhinosinusitis, neonatal respiratory distress, and organ laterality defects. While severe lower respiratory tract infections and bronchiectasis are common in Inuit, PCD has not been recognized in this population.

METHODS

We report a case series of seven Inuit patients with PCD identified by genetic testing in three Canadian PCD centers.

RESULTS

Patients ranged from 4 to 59 years of age (at time of last evaluation) and originated in the Qikiqtaaluk region (Baffin Island, n = 5), Nunavut, or Nunavik (northern Quebec, n = 2), Canada. They had typical features of PCD, including neonatal respiratory distress (five patients), situs inversus totalis (four patients), bronchiectasis (four patients), chronic atelectasis (six patients), and chronic otitis media (six patients). Most had chronic rhinitis. Genetic evaluation demonstrated that all had homozygous pathogenic variants in DNAH11 at NM_001277115.1:c.4095+2C>A.

CONCLUSIONS

The discovery of this homozygous DNAH11 variant in widely disparate parts of the Nunangat (Inuit homelands) suggests this is a founder mutation that may be widespread in Inuit. Thus, PCD may be an important cause of chronic lung, sinus, and middle ear disease in this population. Inuit with chronic lung disease, including bronchiectasis or laterality defects, should undergo genetic testing for PCD. Consideration of including PCD genetic analysis in routine newborn screening should be considered in Inuit regions.

Airway Disease in Children with Primary Ciliary Dyskinesia: Impact of Ciliary Ultrastructure Defect and Genotype

Rationale: Primary ciliary dyskinesia (PCD) is characterized by impaired mucociliary clearance, recurrent respiratory infections, progressive airway damage, and obstructive lung disease. Although the association of ciliary ultrastructure defect/genotype with the severity of airflow obstruction has been well characterized, their association with airway abnormalities on chest computed tomography (CT) has been minimally evaluated. Objectives: We sought to delineate the association of ciliary defect class/genotype with chest CT scores in children with PCD. Methods: Cross-sectional analysis of children with PCD (N = 146) enrolled in a prospective multicenter observational study, stratified by defect type: outer dynein arm (ODA), ODA/inner dynein arm (IDA), IDA/microtubular disorganization (MTD), and normal/near normal ultrastructure with associated genotypes. CTs were scored using the MERAGMA-PCD (Melbourne-Rotterdam Annotated Grid Morphometric Analysis for PCD), evaluating airway abnormalities in a hierarchical order: atelectasis, bronchiectasis, bronchial wall thickening, and mucus plugging/tree-in-bud opacities. The volume fraction of each component was expressed as the percentage of total lung volume. The percentage of disease was computed as the sum of all components. Regression analyses were used to describe the association between clinical predictors and CT scores. Results: Acceptable chest CTs were obtained in 141 children (71 male): 57 ODA, 20 ODA/IDA, 40 IDA/MTD, and 24 normal/near normal. The mean (standard deviation) age was 8.5 (4.6) years, forced expiratory volume in 1 second (FEV1) percent predicted was 82.4 (19.5), and %Disease was 4.6 (3.5). Children with IDA/MTD defects had a higher %Disease compared with children with ODA defects (2.71% higher [95% confidence interval (CI), 1.37-4.06; P < 0.001]), driven by higher %Mucus plugging (2.35% higher [1.43-3.26; P < 0.001]). Increasing age, lower body mass index, and lower FEV1 were associated with a higher %Disease (0.23%; 95% CI, 0.11-0.35; P < 0.001 and 0.03%; 95% CI, 0.01-0.04; P = 0.008 and 0.05%; 95% CI, 0.01-0.08; P = 0.011, respectively). Conclusions: Children with IDA/MTD defects had significantly greater airway disease on CT, primarily mucus plugging, compared with children with ODA defects.

Laterality Defects in Primary Ciliary Dyskinesia: Relationship to Ultrastructural Defect or Genotype

Rationale: The association between organ laterality abnormalities and ciliary ultrastructural defect or genotype in primary ciliary dyskinesia is poorly understood. Objectives: To determine if there is an association between presence and/or type of laterality abnormality and ciliary ultrastructural defect or genotype. Methods: Participants with primary ciliary dyskinesia in a multicenter, prospective study were grouped based on ciliary ultrastructural defect or genotype. In a retrospective analysis of these data, the association of ciliary ultrastructural defect or genotype and likelihood of a laterality abnormality was evaluated by logistic regression adjusted for presence of two loss-of-function versus one or more not-loss-of-function variants. Results: Of 559 participants, 286 (51.2%), 215 (38.5%), and 58 (10.4%) were identified as having situs solitus, situs inversustotalis, and situs ambiguus, respectively; heterotaxy, defined as situs ambiguus with complex cardiovascular defects, was present in 14 (2.5%). Compared with the group with inner dynein arm defects with microtubular disorganization, laterality defects were more likely in the outer dynein arm defects group (odds ratio [OR], 2.07; 95% confidence interval [CI], 1.21-3.54; P < 0.01) and less likely in the normal/near normal ultrastructure group (OR, 0.04; 95% CI, 0.013-0.151; P < 0.01). Heterotaxy was present in 11 of 242 (4.5%) in the outer dynein arm defects group but 0 of 96 in the inner dynein arm defects with microtubular disorganization group (P = 0.038). Conclusion: In primary ciliary dyskinesia, risk of a laterality abnormality differs by ciliary ultrastructural defect. Pathophysiologic mechanisms underlying these differences require further exploration.

Lung ultrasound findings in asymptomatic healthy children with asthma

BACKGROUND

Lung ultrasound (LUS) has been shown to be an effective tool to rapidly diagnose certain causes of pediatric respiratory distress. However, very little is known about LUS findings in pediatric asthma.

OBJECTIVES

The primary objective of this study was to characterize LUS findings in a cohort of pediatric patients with a definitive diagnosis of asthma, outside of an asthma exacerbation.

METHODS

Eligible patients, aged 6-17 years old and diagnosed with asthma, underwent LUS during an outpatient visit. LUS was conducted using a six-zone scanning protocol. Presence of a LUS artifact was defined by one or more of the following: ≥3 B-lines per intercostal space, pulmonary consolidation, and/or pleural abnormality. Images were interpreted by an expert sonographer blinded to patient clinical characteristics.

RESULTS

Fifty-two patients were included. 10/52 (19.2%) patients demonstrated the presence of LUS artifacts: 8 with ≥3 B-lines, 1 with consolidation >1 cm, and 7 with subpleural consolidations <1 cm, 1 with a pleural line abnormality. Artifacts were seen in the right anterior and lateral zones in 60% of participants and were limited to 1-2 intercostal space(s) within one lung zone in all participants. No association was found between presence of LUS artifacts and asthma control or severity.

CONCLUSION

To our knowledge, this is the first report of LUS findings in outpatient pediatric asthma. LUS artifacts in asthmatic children can be seen outside of acute exacerbations. Such baseline findings need to be taken into consideration when using LUS for the acute evaluation of a pediatric patient with asthma.

A multi-disciplinary, comprehensive approach to management of children with heterotaxy

Heterotaxy (HTX) is a rare condition of abnormal thoraco-abdominal organ arrangement across the left-right axis of the body. The pathogenesis of HTX includes a derangement of the complex signaling at the left-right organizer early in embryogenesis involving motile and non-motile cilia. It can be inherited as a single-gene disorder, a phenotypic feature of a known genetic syndrome or without any clear genetic etiology. Most patients with HTX have complex cardiovascular malformations requiring surgical intervention. Surgical risks are relatively high due to several serious comorbidities often seen in patients with HTX. Asplenia or functional hyposplenism significantly increase the risk for sepsis and therefore require antimicrobial prophylaxis and immediate medical attention with fever. Intestinal rotation abnormalities are common among patients with HTX, although volvulus is rare and surgical correction carries substantial risk. While routine screening for intestinal malrotation is not recommended, providers and families should promptly address symptoms concerning for volvulus and biliary atresia, another serious morbidity more common among patients with HTX. Many patients with HTX have chronic lung disease and should be screened for primary ciliary dyskinesia, a condition of respiratory cilia impairment leading to bronchiectasis. Mental health and neurodevelopmental conditions need to be carefully considered among this population of patients living with a substantial medical burden. Optimal care of children with HTX requires a cohesive team of primary care providers and experienced subspecialists collaborating to provide compassionate, standardized and evidence-based care. In this statement, subspecialty experts experienced in HTX care and research collaborated to provide expert- and evidence-based suggestions addressing the numerous medical issues affecting children living with HTX.

Characterizing pediatric lung ultrasound findings during a chemically induced bronchospasm

BACKGROUND

Lung ultrasound (LUS) has been shown to be a useful clinical tool in pediatrics, but very little is known about the LUS findings of asthma in children.

OBJECTIVES

The primary objective was to characterize LUS findings of pediatric patients before and after a chemically induced bronchospasm. The secondary objective was to evaluate the effect of bronchodilators on LUS findings.

METHODS

Eligible children 6-17 years old presenting for a methacholine challenge test (MCT) in a pediatric respiratory clinic were recruited. Patients with viral symptoms were excluded. A six-zone LUS protocol was performed before and after the MCT, and after bronchodilator administration; video recordings were analysed by an expert blinded to the patient characteristics and MCT results.

RESULTS

Forty-four patients were included in the study. Five patients had positive LUS findings at baseline. Nine patients out of 29 (31%) had new-onset positive LUS following a reactive MCT. There was a significant association between having a chemically induced bronchospasm and a positive LUS post-MCT (odds ratio [95% confidence interval]: 5.3 [1.0-27.7]; p = 0.05). Among patients who developed positive LUS findings post-MCT, four out of nine returned to having a negative LUS postbronchodilator administration.

CONCLUSIONS

This is the first known report of an association between LUS findings and bronchospasm in pediatric patients. It is also the first documentation of resolution of LUS findings postbronchodilator administration. Most LUS findings observed were small and limited to a few intercostal spaces. Further research is required to quantify these findings and evaluate the effect of salbutamol on LUS.

Going beyond the chest X-ray: Investigating laterality defects in primary ciliary dyskinesia

BACKGROUND

Organ laterality defects in primary ciliary dyskinesia (PCD) are common, ranging from complete mirror image organ arrangement, situs inversus totalis (SIT), to situs ambiguus (SA), which falls along the spectrum of situs solitus (SS) and SIT. Targeted investigations for organ laterality defects are not universally recommended in PCD consensus statements. Without investigations beyond chest radiography (CXR), clinically significant defects may go undetected leading to increased morbidity. We hypothesize that clinically significant SA defects remain undetected on CXR and targeted investigations are needed to detect various laterality defects associated with morbidity.

METHODS

This retrospective study collected data from PCD clinics at two Canadian children's hospitals from 2012 to 2020. Participants <30 years old with a confirmed or clinical diagnosis of PCD were enrolled. CXR images were reviewed, and reports of other targeted investigations, including chest computed tomography, abdominal ultrasound, echocardiogram, upper gastrointestinal series, and splenic function studies, were extracted from medical records. Situs classifications from CXR alone versus CXR with add-on targeted investigations were compared using Cochran's q and McNemar tests.

RESULTS

One hundred and fifty-nine PCD patients were included, median age at PCD diagnosis of 6.1 years (range: 0-28). The situs classification differed significantly from CXR images alone versus CXR with add-on targeted investigations (p < 0.001); SS 88 (55%) versus 75 (47%), SIT 59 (37%) versus 46 (29%), and SA 12 (8%) versus 38 (24%). Identified SA defects were cardiovascular (21, 13%), intestinal (9, 6%), and/or splenic (16,10%).

CONCLUSIONS

In PCD patients, clinically significant SA defects may not be detected by CXR alone. Our results suggest that the routine use of CXR with add-on targeted investigations may be justified.

Novel MYO1D Missense Variant Identified Through Whole Exome Sequencing and Computational Biology Analysis Expands the Spectrum of Causal Genes of Laterality Defects

Laterality defects (LDs) or asymmetrically positioned organs are a group of rare developmental disorders caused by environmental and/or genetic factors. However, the exact molecular pathophysiology of LD is not yet fully characterised. In this context, studying Arab population presents an ideal opportunity to discover the novel molecular basis of diseases owing to the high rate of consanguinity and genetic disorders. Therefore, in the present study, we studied the molecular basis of LD in Arab patients, using next-generation sequencing method. We discovered an extremely rare novel missense variant in MYO1D gene (Pro765Ser) presenting with visceral heterotaxy and left isomerism with polysplenia syndrome. The proband in this index family has inherited this homozygous variant from her heterozygous parents following the autosomal recessive pattern. This is the first report to show MYO1D genetic variant causing left-right axis defects in humans, besides previous known evidence from zebrafish, frog and Drosophila models. Moreover, our multilevel bioinformatics-based structural (protein variant structural modelling, divergence, and stability) analysis has suggested that Ser765 causes minor structural drifts and stability changes, potentially affecting the biophysical and functional properties of MYO1D protein like calmodulin binding and microfilament motor activities. Functional bioinformatics analysis has shown that MYO1D is ubiquitously expressed across several human tissues and is reported to induce severe phenotypes in knockout mouse models. In conclusion, our findings show the expanded genetic spectrum of LD, which could potentially pave way for the novel drug target identification and development of personalised medicine for high-risk families.

Otolaryngology Manifestations of Primary Ciliary Dyskinesia: A Multicenter Study

OBJECTIVE

This project aims to prospectively and objectively assess otolaryngological manifestations and quality of life of children with primary ciliary dyskinesia (PCD) and compare these findings with healthy pediatric controls.

STUDY DESIGN

Cross-sectional.

SETTING

Two high-volume pediatric PCD specialty centers.

METHODS

Standardized clinical assessment; Sino-Nasal Outcome Test 22 (SNOT-22); Hearing Environment and Reflection Quality of Life (HEAR-QL); Reflux Symptom Index (RSI); standardized physical examination of the sinonasal, laryngeal, and otological systems; and investigations including pure-tone audiograms (PTAs) and sinonasal cultures were collected.

RESULTS

Forty-seven children with PCD and 25 control participants were recruited. Children with PCD had more upper airway symptoms than healthy children. They had significantly higher scores in both SNOT-22 and RSI, indicating worse sinonasal and reflux symptoms, with worse quality of life on the HEAR-QL index compared to healthy children (P < .05). Fifty-two percent of children with PCD-related hearing loss were not aware of their hearing deficit that was present on audiological assessment, and only 23% of children who had ventilation tubes had chronic otorrhea, most of which was easily controlled with ototopic drops. Furthermore, although all children with PCD had chronic rhinosinusitis, only 36% of them were using topical nasal treatment. The most common bacteria cultured from the middle meatus were Staphylococcus aureus in 11 of 47 (23%), followed by Streptococcus pneumoniae in 10 of 47 (21%).

CONCLUSION

This multisite cohort highlights the importance of otolaryngology involvement in the management of children with PCD. More rigorous otolaryngological management may lead to reductions in overall morbidity and improve quality of life for children with PCD.

Autosomal dominant variants in FOXJ1 causing primary ciliary dyskinesia in two patients with obstructive hydrocephalus

Background

Primary ciliary dyskinesia (PCD) is a mostly autosomal recessive, genetic disease of abnormal motile cilia function, resulting in bronchiectasis, infertility, organ laterality defects, and chronic otolaryngology disease. Though motile, ependymal cilia influencing cerebrospinal fluid flow in the central nervous system share many aspects of structure and function with motile cilia in the respiratory tract, hydrocephalus is rarely associated with PCD. Recently, pathogenic variants in FOXJ1 (Chr 17q25.1) were identified causing PCD associated with hydrocephalus, reduced respiratory cilia number, axonemal microtubule disorganization, and occurring in a de novo, autosomal dominant inheritance pattern.

Method

Two patients with chronic oto‐sino‐pulmonary disease and hydrocephalus underwent candidate testing of FOXJ1. Coding region and splice junctions were sequenced and analyzed under the auspices of Genetic Disorders of Mucociliary Clearance Consortium.

Results

Upon sequencing of the entire coding region and splice‐junctions, heterozygous, pathogenic variants in FOXJ1 were discovered in exon 3 of two patients: an 11‐month‐old female with situs inversus totalis (NM_001454.4: c.945delC (p.Phe315Leufs*18)) and a 51 year‐old male, post‐double lung transplantation (NM_001454.4: c.929_932delACTG (p.Asp310Glyfs*22)). FOXJ1 variants were not detected in the available parents and the siblings of these probands.

Conclusion

FOXJ1 pathogenic variants cause PCD in a de novo, autosomal dominant inheritance pattern, and are associated with hydrocephalus. Physicians treating patients with hydrocephalus and chronic oto‐sino‐pulmonary disease should be aware of this PCD association and test for FOXJ1 variants.

Diagnosis of Primary Ciliary Dyskinesia. An Official American Thoracic Society Clinical Practice Guideline

BACKGROUND

This document presents the American Thoracic Society clinical practice guidelines for the diagnosis of primary ciliary dyskinesia (PCD).

TARGET AUDIENCE

Clinicians investigating adult and pediatric patients for possible PCD.

METHODS

Systematic reviews and, when appropriate, meta-analyses were conducted to summarize all available evidence pertinent to our clinical questions. Evidence was assessed using the GRADE (Grading of Recommendations, Assessment, Development and Evaluation) approach for diagnosis and discussed by a multidisciplinary panel with expertise in PCD. Predetermined conflict-of-interest management strategies were applied, and recommendations were formulated, written, and graded exclusively by the nonconflicted panelists. Three conflicted individuals were also prohibited from writing, editing, or providing feedback on the relevant sections of the manuscript.

RESULTS

After considering diagnostic test accuracy, confidence in the estimates for each diagnostic test, relative importance of test results studied, desirable and undesirable direct consequences of each diagnostic test, downstream consequences of each diagnostic test result, patient values and preferences, costs, feasibility, acceptability, and implications for health equity, the panel made recommendations for or against the use of specific diagnostic tests as compared with using the current reference standard (transmission electron microscopy and/or genetic testing) for the diagnosis of PCD.

CONCLUSIONS

The panel formulated and provided a rationale for the direction as well as for the strength of each recommendation to establish the diagnosis of PCD.

Primary Ciliary Dyskinesia: Longitudinal Study of Lung Disease by Ultrastructure Defect and Genotype

RATIONALE

In primary ciliary dyskinesia, factors leading to disease heterogeneity are poorly understood.

OBJECTIVES

To describe early lung disease progression in primary ciliary dyskinesia and identify associations between ultrastructural defects and genotypes with clinical phenotype.

METHODS

This was a prospective, longitudinal (5 yr), multicenter, observational study. Inclusion criteria were less than 19 years at enrollment and greater than or equal to two annual study visits. Linear mixed effects models including random slope and random intercept were used to evaluate longitudinal associations between the ciliary defect group (or genotype group) and clinical features (percent predicted FEV1 and weight and height z-scores).

MEASUREMENTS AND MAIN RESULTS

A total of 137 participants completed 732 visits. The group with absent inner dynein arm, central apparatus defects, and microtubular disorganization (IDA/CA/MTD) (n = 41) were significantly younger at diagnosis and in mixed effects models had significantly lower percent predicted FEV1 and weight and height z-scores than the isolated outer dynein arm defect (n = 55) group. Participants with CCDC39 or CCDC40 mutations (n = 34) had lower percent predicted FEV1 and weight and height z-scores than those with DNAH5 mutations (n = 36). For the entire cohort, percent predicted FEV1 decline was heterogeneous with a mean (SE) decline of 0.57 (0.25) percent predicted/yr. Rate of decline was different from zero only in the IDA/MTD/CA group (mean [SE], -1.11 [0.48] percent predicted/yr; P = 0.02).

CONCLUSIONS

Participants with IDA/MTD/CA defects, which included individuals with CCDC39 or CCDC40 mutations, had worse lung function and growth indices compared with those with outer dynein arm defects and DNAH5 mutations, respectively. The only group with a significant lung function decline over time were participants with IDA/MTD/CA defects.

The prevalence of the defining features of primary ciliary dyskinesia within a cri du chat syndrome cohort

BACKGROUND

Primary ciliary dyskinesia (PCD) and cri du chat syndrome (CdCS) are distinct disorders that can co-occur due to a common genetic locus on chromosome 5p. Chronic respiratory symptoms associated with PCD can occur in CdCS and are typically attributed to hypotonia, dysphagia, and aspiration. The prevalence of PCD among individuals with CdCS is not known.

METHODS

An online survey assessing common features of PCD was distributed to members of the 5P Minus Society, a cri du chat patient advocacy group. Respondents who met criteria for elevated risk of PCD (at least 3 symptoms or other features highly suggestive of PCD) were offered PCD genetic testing.

RESULTS

For the 123 respondents (median age 10.1 years with IQR 5.5-17.3 years; from 33 U.S. states and 10 other countries) chronic respiratory symptoms associated with PCD were prevalent, including unexplained neonatal respiratory distress, year-round nasal congestion beginning in infancy, and year-round, wet cough beginning in infancy in 35%, 32%, and 20% of respondents, respectively. Fifteen respondents (12%) met criteria for elevated risk for PCD and completed genetic analysis; however, none were diagnostic for PCD. A PCD clinical center evaluated an additional subject with CdCS who met criteria for likely PCD and had negative genetics, but had diagnostic electron microscopy of the respiratory cilia (missing outer dynein arms).

CONCLUSION

Clinicians should be aware of the genetic connection between CdCS and PCD. Non-informative genetic testing does not rule out PCD. CdCS patients with chronic respiratory symptoms may benefit from referral to specialized PCD diagnostic centers.

Value of transmission electron microscopy for primary ciliary dyskinesia diagnosis in the era of molecular medicine: Genetic defects with normal and non-diagnostic ciliary ultrastructure

Primary ciliary dyskinesia (PCD) is a genetic disorder causing chronic oto-sino-pulmonary disease. No single diagnostic test will detect all PCD cases. Transmission electron microscopy (TEM) of respiratory cilia was previously considered the gold standard diagnostic test for PCD, but 30% of all PCD cases have either normal ciliary ultrastructure or subtle changes which are non-diagnostic. These cases are identified through alternate diagnostic tests, including nasal nitric oxide measurement, high-speed videomicroscopy analysis, immunofluorescent staining of axonemal proteins, and/or mutation analysis of various PCD causing genes. Autosomal recessive mutations in DNAH11 and HYDIN produce normal TEM ciliary ultrastructure, while mutations in genes encoding for radial spoke head proteins result in some cross-sections with non-diagnostic alterations in the central apparatus interspersed with normal ciliary cross-sections. Mutations in nexin link and dynein regulatory complex genes lead to a collection of different ciliary ultrastructures; mutations in CCDC65, CCDC164, and GAS8 produce normal ciliary ultrastructure, while mutations in CCDC39 and CCDC40 cause absent inner dynein arms and microtubule disorganization in some ciliary cross-sections. Mutations in CCNO and MCIDAS cause near complete absence of respiratory cilia due to defects in generation of multiple cellular basal bodies; however, the scant cilia generated may have normal ultrastructure. Lastly, a syndromic form of PCD with retinal degeneration results in normal ciliary ultrastructure through mutations in the RPGR gene. Clinicians must be aware of these genetic causes of PCD resulting in non-diagnostic TEM ciliary ultrastructure and refrain from using TEM of respiratory cilia as a test to rule out PCD.

An Official American Thoracic Society Workshop Report: Translational Research in Rare Respiratory Diseases

Rare respiratory diseases (RRDs) are a heterogeneous group of disorders that collectively represent a significant health care burden. In recent years, strong advocacy and policy initiatives have led to advances in the implementation of research and clinical care for rare diseases. The development of specialized centers and research networks has facilitated support for affected individuals as well as emerging programs in basic, translational, and clinical research. In selected RRDs, subsequent gains in knowledge have informed the development of targeted therapies and effective diagnostic tests, but many gaps persist. There was therefore a desire to identify the elements contributing to an effective translational research program in RRDs. To this end, a workshop was convened in October 2015 with a focus on the implementation of effective transnational research networks and collaborations aimed at developing novel diagnostic and therapeutic tools. Key elements included an emphasis on molecular pathogenesis, the continuing engagement of patient advocacy groups and policy makers, the effective use of preclinical models in the translational research pipeline, and the detailed phenotyping of patient cohorts. During the course of the workshop, current logistical and knowledge gaps were identified, and new solutions or opportunities were highlighted.

Point of care lung ultrasound of children with acute asthma exacerbations in the pediatric ED

OBJECTIVES

Primary objective was to characterize lung ultrasound findings in children with asthma presenting with respiratory distress to the emergency department (ED). Secondary objectives included correlating these findings with patients' clinical course in the ED.

METHODS

Eligible patients 2-17years of age, underwent a lung ultrasound by the study sonographer between November 2014 to December 2015. Positive lung ultrasound was defined as the presence of ≥1 of the following findings: ≥3 B-lines per intercostal space, consolidation and/or pleural abnormalities. The treating physician remained blinded to ultrasound findings; clinical course was extracted from the medical chart.

RESULTS

A total of sixty patients were enrolled in this study. Lung ultrasound was positive in 45% (27/60) of patients: B-line pattern in 38%, consolidation in 30% and pleural line abnormalities in 12%. A positive lung ultrasound correlated with increased utilization of antibiotics (26% vs 0%, p=0.03), prolonged ED length of stay (30% vs. 9%, p=0.04) and admission rate (30% vs 0%, p=0.03). Inter-rater agreement between novice and expert sonographers was excellent with a kappa of 0.92 (95% CI: 0.84-1.00).

CONCLUSIONS

This study characterized lung ultrasound findings in pediatric patients presenting with acute asthma exacerbations; nearly half of whom had a positive lung ultrasound. Positive lung ultrasounds were associated with increased ED and hospital resource utilization. Future prospective studies are needed to determine the utility and reliability of this tool in clinical practice.

Point-of-care lung ultrasound in young children with respiratory tract infections and wheeze

OBJECTIVE

Characterise lung ultrasound (LUS) findings, diagnostic accuracy and agreement between novice and expert interpretations in young children with respiratory tract infections and wheeze.

METHODS

Prospective cross-sectional study in a paediatric ED. Patients ≤2 years with a respiratory tract infection and wheeze at triage were recruited unless in severe respiratory distress. Prior to clinical management, a novice sonologist performed the LUS using a six-zone scanning protocol. The treating physician remained blinded to ultrasound findings; final diagnoses were extracted from the medical record. An expert sonologist, blinded to all clinical information, assessed the ultrasound video clips at study completion. Positive LUS was defined as the presence of ≥1 of the following findings: ≥3 B-lines per intercostal space, consolidation and/or pleural abnormalities.

RESULTS

Ninety-four patients were enrolled (median age 11.1 months). LUS was positive in 42% (39/94) of patients (multiple B-lines in 80%, consolidation in 64%, pleural abnormalities in 23%). The proportion of positive LUS, along with their diagnostic accuracy (sensitivity (95% CI), specificity (95% CI)), were as follows for children with bronchiolitis, asthma, pneumonia and asthma/pneumonia: 46% (45.8% (34.0% to 58.0%), 72.7% (49.8% to 89.3%)), 0% (0% (0.0% to 23.3%), 51.3% (39.8% to 62.6%)), 100% (100% (39.8% to 100.0%), 61.1% (50.3% to 71.2%)), 50% (50% (6.8% to 93.2%), 58.9% (48.0% to 69.2%)), respectively. There was good agreement between the novice and expert sonographers for a positive LUS (kappa 0.68 (95% CI 0.54 to 0.82)).

CONCLUSIONS

Among children with respiratory tract infections and wheeze, a positive LUS seems to distinguish between clinical syndromes by ruling in pneumonia and ruling out asthma. If confirmed in future studies, LUS may emerge as a point-of-care tool to guide diagnosis and disposition in young children with wheeze.

When to suspect primary ciliary dyskinesia in children

Primary ciliary dyskinesia [PCD] is an uncommon, autosomal recessively inherited condition that is often overlooked and undertreated in childhood. Amidst the myriad of children with coloured nasal secretions, otitis media and a wet cough, there exists a subset with PCD as the underlying unifying diagnosis. In this paper we have highlighted the varying clinical manifestations of PCD, emphasising different presentations between neonates, toddlers, school aged children and adults.

Diagnosis, monitoring, and treatment of primary ciliary dyskinesia: PCD foundation consensus recommendations based on state of the art review

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous, rare lung disease resulting in chronic oto-sino-pulmonary disease in both children and adults. Many physicians incorrectly diagnose PCD or eliminate PCD from their differential diagnosis due to inexperience with diagnostic testing methods. Thus far, all therapies used for PCD are unproven through large clinical trials. This review article outlines consensus recommendations from PCD physicians in North America who have been engaged in a PCD centered research consortium for the last 10 years. These recommendations have been adopted by the governing board of the PCD Foundation to provide guidance for PCD clinical centers for diagnostic testing, monitoring, and appropriate short and long-term therapeutics in PCD patients.

Clinical features of childhood primary ciliary dyskinesia by genotype and ultrastructural phenotype

RATIONALE

The relationship between clinical phenotype of childhood primary ciliary dyskinesia (PCD) and ultrastructural defects and genotype is poorly defined.

OBJECTIVES

To delineate clinical features of childhood PCD and their associations with ultrastructural defects and genotype.

METHODS

A total of 118 participants younger than 19 years old with PCD were evaluated prospectively at six centers in North America using standardized procedures for diagnostic testing, spirometry, chest computed tomography, respiratory cultures, and clinical phenotyping.

MEASUREMENTS AND MAIN RESULTS

Clinical features included neonatal respiratory distress (82%), chronic cough (99%), and chronic nasal congestion (97%). There were no differences in clinical features or respiratory pathogens in subjects with outer dynein arm (ODA) defects (ODA alone; n = 54) and ODA plus inner dynein arm (IDA) defects (ODA + IDA; n = 18) versus subjects with IDA and central apparatus defects with microtubular disorganization (IDA/CA/MTD; n = 40). Median FEV1 was worse in the IDA/CA/MTD group (72% predicted) versus the combined ODA groups (92% predicted; P = 0.003). Median body mass index was lower in the IDA/CA/MTD group (46th percentile) versus the ODA groups (70th percentile; P = 0.003). For all 118 subjects, median number of lobes with bronchiectasis was three and alveolar consolidation was two. However, the 5- to 11-year-old IDA/CA/MTD group had more lobes of bronchiectasis (median, 5; P = 0.0008) and consolidation (median, 3; P = 0.0001) compared with the ODA groups (median, 3 and 2, respectively). Similar findings were observed when limited to participants with biallelic mutations.

CONCLUSIONS

Lung disease was heterogeneous across all ultrastructural and genotype groups, but worse in those with IDA/CA/MTD ultrastructural defects, most of whom had biallelic mutations in CCDC39 or CCDC40.

Laterality defects other than situs inversus totalis in primary ciliary dyskinesia: insights into situs ambiguus and heterotaxy

BACKGROUND

Motile cilia dysfunction causes primary ciliary dyskinesia (PCD), situs inversus totalis (SI), and a spectrum of laterality defects, yet the prevalence of laterality defects other than SI in PCD has not been prospectively studied.

METHODS

In this prospective study, participants with suspected PCD were referred to our multisite consortium. We measured nasal nitric oxide (nNO) level, examined cilia with electron microscopy, and analyzed PCD-causing gene mutations. Situs was classified as (1) situs solitus (SS), (2) SI, or (3) situs ambiguus (SA), including heterotaxy. Participants with hallmark electron microscopic defects, biallelic gene mutations, or both were considered to have classic PCD.

RESULTS

Of 767 participants (median age, 8.1 years, range, 0.1-58 years), classic PCD was defined in 305, including 143 (46.9%), 125 (41.0%), and 37 (12.1%) with SS, SI, and SA, respectively. A spectrum of laterality defects was identified with classic PCD, including 2.6% and 2.3% with SA plus complex or simple cardiac defects, respectively; 4.6% with SA but no cardiac defect; and 2.6% with an isolated possible laterality defect. Participants with SA and classic PCD had a higher prevalence of PCD-associated respiratory symptoms vs SA control participants (year-round wet cough, P < .001; year-round nasal congestion, P = .015; neonatal respiratory distress, P = .009; digital clubbing, P = .021) and lower nNO levels (median, 12 nL/min vs 252 nL/min; P < .001).

CONCLUSIONS

At least 12.1% of patients with classic PCD have SA and laterality defects ranging from classic heterotaxy to subtle laterality defects. Specific clinical features of PCD and low nNO levels help to identify PCD in patients with laterality defects.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00323167; URL: www.clinicaltrials.gov.

Cri du chat syndrome and primary ciliary dyskinesia: a common genetic cause on chromosome 5p

Cri du chat syndrome (CdCS) and primary ciliary dyskinesia (PCD) are rare diseases that present with frequent respiratory symptoms. PCD can be caused by hemizygous DNAH5 mutation in combination with a 5p segmental deletion attributable to CdCS on the opposite chromosome. Chronic oto-sino-pulmonary symptoms or organ laterality defects in CdCS should prompt an evaluation for PCD.

Filamin A mutation may be associated with diffuse lung disease mimicking bronchopulmonary dysplasia in premature newborns

Bronchopulmonary dysplasia (BPD) is a common long-term complication in premature newborns requiring ventilatory support and is the most common cause of chronic diffuse lung disease in this population. We present the clinical course of a premature newborn with a complicated neonatal respiratory course that was initially thought to be related to BPD, but it did not respond to the typical therapies for this condition. Due to the findings of periventricular nodular heterotopia, the diagnosis of a filamin A gene mutation was eventually made, which explained the respiratory pathology of this patient. When time of onset and clinical course do not correlate with typical BPD, one should consider alternative diagnoses in premature infants, including neonatal diffuse lung disease.

Abstract P3-12-02: The impact of estrogen receptor status on treatment outcomes following gamma knife radiosurgery for brain metastases of primary breast cancer

INTRODUCTION: Estrogen receptor (ER) status is a critical component of determining initial therapy of newly diagnosed breast cancer. Although 70% of primary breast malignancies are ER+, there remains limited data on whether ER status influences treatment outcomes for patients with brain metastases. Gamma Knife Radiosurgery (GKS) is increasingly being used in the management of brain metastases. The goal of this study is to determine the impact of ER status in patients receiving GKS for breast cancer metastases to brain.

METHODS: A database of consecutive breast cancer patients receiving GKS at our institution from January 2000 to March 2012 was reviewed for hormone receptor status, dates of initial brain metastasis and GKS, presence of neurologic symptoms, and recurrence of GKS-treated lesions. The main cohort was subdivided by receptor status at initial tissue diagnosis. Progression or loss of local control of the treated lesions was defined as radiographic evidence of growth (greater than 20% increase in the sum of the longest diameters) or treated lesions requiring additional treatment until death or last follow-up. Analysis for neurological symptom improvement was performed for patients with available follow-up information, with at least 1 month follow–up. Comparisons were made between subgroups using Kaplan-Meier method, Chi-square analysis and univariate comparisons with log-rank test. Significance was set at p &lt; 0.05.

RESULTS: A total of 93 breast cancer patients received GKS, and receptor status was available in 83 patients. Forty-six (45.7%) percent of patients were ER+. The median follow-up for all patients was 85.5 months (range 2.5 to 307.6). For all patients, the median number of brain metastases was 2.0 and median age at diagnosis was 54 years. According to ER status, there were no differences in patient age at diagnosis, age at GKS, or number of brain metastasis, although the time to development of brain metastasis (median 92.2 vs 34.0 months, p = 0.02) was longer in the ER+ cohort. The median GKS dose was 18 Gy. Fifty one percent of ER+ patients had GKS alone versus 54% of ER− patients (p = 0.26). There was no difference in survival from GKS according to ER status, with survival for ER+ and ER− patients of 21.3 and 16.8 months, respectively (p = 0.39). However, ER+ patients exhibited longer progression-free survival of treated metastases with 19.1 versus 7.5 months (p = 0.02). In addition, for all patients who attained local control, 10 of 22 ER+ patients had an improvement in neurologic symptoms versus 4 of 17 ER− patients (p = 0.02).

DISCUSSION: While ER positivity conveys a favorable prognosis at the time of diagnosis, survival after intensive treatment of brain metastases appears similar to ER− patients. This occurs independently of ER status, even though brain relapse was significantly more common in ER− patients, suggesting efforts to further improve extracranial systemic control may potentially enhance survival. Both local and neurologic symptom control were poorer for ER− patients. Whether alternative approaches, such as increasing GKS dose, surgical resection, and/or routine inclusion of WBRT, can improve outcomes for ER− patients with brain metastases may warrant future investigation.

Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P3-12-02.

Asymmetric domain nucleation and unusual magnetization reversal in ultrathin Co films with perpendicular anisotropy

We report unexpected phenomena during magnetization reversal in ultrathin Co films and Co/Pt multilayers with perpendicular anisotropy. Using magneto-optical Kerr microscopy and magnetic force microscopy we have observed asymmetrical nucleation centers where the reversal begins for one direction of the field only and is characterized by an acute asymmetry of domain-wall mobility. We have also observed magnetic domains with a continuously varying average magnetization, which can be explained in terms of the coexistence of three magnetic phases: up, down, and striped.

Antisymmetric magnetoresistance in magnetic multilayers with perpendicular anisotropy

While magnetoresistance (MR) has generally been found to be symmetric in applied field in nonmagnetic or magnetic metals, we have observed antisymmetric MR in Co/Pt multilayers. Simultaneous domain imaging and transport measurements show that the antisymmetric MR is due to the appearance of domain walls that run perpendicular to both the magnetization and the current, a geometry existing only in materials with perpendicular magnetic anisotropy. As a result, the extraordinary Hall effect gives rise to circulating currents in the vicinity of the domain walls that contributes to the MR. The antisymmetric MR and extraordinary Hall effect have been quantitatively accounted for by a theoretical model.

Tensile strength of wound closure with cyanoacrylate glue

2-Octyl cyanoacrylate tissue adhesive is increasingly being used for closure of traumatic lacerations. Data regarding the strength of incisions closed with 2-octyl cyanoacrylate are limited. We compared the strength of disruption of closure with glue with that of more conventional methods of wound closure. Segments of fresh porcine skin measuring 3.5 x 10 cm were approximated by one of four methods: 1) 2-octyl cyanoacrylate glue, 2) surgical staples, 3) 0.5 inch Steri-Strips, and 4) interrupted 4-0 poliglecaprone 25 sutures in a subcuticular fashion. Fifteen specimens were used to test each type of closure. The strength of closure was tested on an Instron 4502 tensionometer. The peak force required for disruption of the closure was recorded and the strength of the closure was compared. Staples provided the strongest closure. Skin glue proved superior to Steri-Strips but inferior to stapled closure. The difference between skin glue and suture closure was not statistically significant (P = 0.12). Patterns of failure differed between the groups. Skin glue failed because of disruption of the skin-glue interface. 2-Octyl cyanoacrylate glue provides a wound closure that is similar to closure with an interrupted subcuticular absorbable suture. This study validates the clinical use of skin glue for closure of surgical incisions. The technique should be used with caution in areas of the body that are subject to tension.

Facial fractures in a level I trauma centre: the importance of protective devices and alcohol abuse

Urban trauma centres have recently noted a shift in the causative mechanism of facial fractures away from motor vehicle crashes (MVC) to blunt assaults (BA). This study was conducted to examine the incidence and aetiology of facial fractures at our institution as well as the relationship with alcohol and protective device use. Trauma registry records of all patients admitted to a level I trauma centre from 1 January 1988 to 1 January 1999 were reviewed. There were 13594 trauma admissions during the 11-year period. Facial fractures were sustained by 1429 patients (10.5%) and this group forms the subject of this study. MVC was the predominant aetiology (59.9%) followed by BA (18.8%). Facial fractures were found in 9.5% of restrained MVC patients compared to 15.4% of unrestrained patients (P<0.00l). Non-helmeted motorcyclists were four times more likely to sustain facial fractures (4.3% vs. 18.4%) than helmeted patients (P<0.00l). 39.6% of patients in the MVC group were legally intoxicated compared to 73.5% in the BA group (P<0.00l). 45.4% of unrestrained patients with facial fractures were intoxicated compared to 11.8% of restrained MVC patients with facial fractures (P<0.001). MVC continue to be the primary aetiology of facial fractures in our trauma population. Protective devices decrease the incidence of facial fractures. Lack of protective device use and the consumption of alcohol correlate with sustaining facial fractures.

Port-site recurrence reproduced in the VX-2 rabbit carcinoma model: an in vivo model comparing laparoscopic port sites and open incisions

BACKGROUND

The use of advanced laparoscopy remains controversial in the field of surgical oncology because the potential for port-site recurrence may violate sound oncologic principles. Two mechanisms are theorized to be the cause of port-site recurrences: first, indirect contamination caused by pneumoperitoneum, aerosolization, or intraperitoneal spread, and second, direct contamination by physical trocar seeding.

METHODS

A VX-2 carcinoma cell suspension was transferred under the left renal capsule of 31 rabbits with either an open flank incision (16) or laparoscopy (15). Animals were observed for tumor recurrence at the video port, the working port, and the open incision. Intraoperative findings and necropsy were used to document recurrence.

RESULTS

The open incision technique resulted in local tumor recurrence in 1/16 animals with 16/16 viable intraabdominal tumors. The laparoscopic technique resulted in 0/15 video port-site recurrences and 9/15 working port-site recurrences, with 14/15 viable intraabdominal tumors. Recurrence at the laparoscopic working port occurred more frequently than in the open (P < 0.02) or laparoscopic video port groups (P < 0.007). No significant difference existed in recurrence between the open incision and the laparoscopic video port (P > 0.5).

CONCLUSIONS

Laparoscopic port-site recurrences can be reproduced using the transplantable VX-2 rabbit carcinoma model. In the VX-2 model, trocar recurrence is the result of direct contamination via surgical instrumentation of viable tumor cells. The effect of the pneumoperitoneum or intraperitoneal cytological spillage (indirect contamination) does not have any effect on trocar recurrence. This model can be used to test and improve laparoscopic techniques to minimize the risk of port-site recurrence. Until technological advances have eliminated the risk of trocar recurrences, direct contact between malignant cells and laparoscopic instruments should be performed with caution.

Managing the nondeflating urethral catheter

BACKGROUND

Urethral catheterization is a routinely performed procedure in hospitalized patients. Numerous complications have been reported secondary to urethral catheter placement.

METHODS

The medical literature was searched using the following key words: "urethral catheter," "complications," and "management." A case report is described and a review of the literature is provided to assist in managing the nondeflating urethral catheter balloon.

RESULTS AND CONCLUSIONS

All physicians who order urethral catheters must be aware of the possibility of a nondeflating catheter balloon and be comfortable with its initial management. The literature has an abundance of techniques for managing the nondeflating urethral catheter balloon. The approach and algorithm provided serve as a guide for the management of this complication by the family physician.

Asymmetry in elementary events of magnetization reversal in a ferromagnetic/antiferromagnetic bilayer

Real-time magneto-optical indicator film images reveal distinct asymmetry in the motion of a single domain wall in a wedged-NiFe/uniform-FeMn bilayer due to the nucleation and behavior of an exchange spring in the antiferromagnetic layer. Magnetization reversal from the ground state begins at the thick end of the wedge where the exchange anisotropy field (HE) is minimal and the magnetostatic field (HMS) is maximal, whereas reversal into the ground state begins from the thin end where HE is maximal and HMS is minimal.

Predicting conversion of laparoscopic cholecystectomy for acute cholecystitis

BACKGROUND AND OBJECTIVES

Laparoscopic cholecystectomy can be safely performed in patients with acute cholecystitis. However, the rate of conversion to open cholecystectomy remains higher when compared with patients with chronic cholecystitis. Preoperative clinical or laboratory parameters that could predict the need for conversion may assist the surgeon in preoperative or intraoperative decision making. This could have cost-saving implications.

METHODS

A retrospective review of 46 patients undergoing laparoscopic cholecystectomy for acute cholecystitis was performed. Records were assessed for preoperative clinical, laboratory and radiographic parameters on admission. Temperature and laboratory parameters were also recorded prior to surgery after an initial period of hospitalization that included intravenous antibiotics. The effect of admission and preoperative parameters as well as the trend in these parameters prior to surgery upon the rate of conversion to open cholecystectomy was assessed.

RESULTS

Ten patients (22%) required conversion to open cholecystectomy. Conversion was required more often in males (43%) when compared with females (4%) (p=0.003). Conversion rate was 30% in patients with increased wall thickness by ultrasound compared with 12% for patients without wall thickening (p=ns). No admission or preoperative laboratory values predicted conversion. The trend in the patient's temperature (p=0.0003) and serum LDH value (p=0.043) predicted the need for conversion to open surgery.

CONCLUSIONS

Preoperative prediction of the need for open cholecystectomy remains elusive. Male patients and patients with rising temperature and LDH levels while on intravenous antibiotics require conversion at increased frequency. However, the benefits of laparoscopic cholecystectomy warrant an attempt at laparoscopic removal in most patients with acute cholecystitis.

An in vitro diffusion model for the study of calcification of bovine pericardium tissue

Bovine pericardium (BP) is extensively used for the production of heart valve bioprostheses. BP has excellent mechanical properties but a limited lifespan because of intrinsic subsurface calcification in vivo. In this study, the in vitro mineralization of BP was investigated by a novel diffusion cell model. In two sets of experiments, glutaraldehyde-treated BP membranes were placed between two compartments, both of which contained calcium phosphate solutions made by equilibration of octacalcium phosphate (Exp I) or dicalcium phosphate dihydrate (Exp II) in phosphoric acid. The movement of calcium (Ca), phosphate (P), and protons through the BP membrane was followed throughout the diffusion process. Histology, scanning electron microscopy, wet chemical analysis, and energy dispersive X-ray analyses provided good evidence of subsurface mineralization of BP that resembled in vivo mineral deposition. Energy dispersive x-ray microanalyses found a Ca/P heterogeneity of the early subsurface mineral that formed in the membrane. The use of a diffusion cell to model BP calcification under well-characterized conditions has led to in vitro mineralization that more closely matches that observed in vivo. The results suggest that this in vitro diffusion model can be used to study the mechanism of pathological mineralization. This model has the potential to provide rapid, inexpensive, basic information about the mineralization process.

Energy-Filtered High-Resolution Electron Microscopy for Quantitative Solid State Structure Determination

Energy-filtered (or selected) electron imaging is one of the future directions of high-resolution electron microscopy (HREM). In this paper, the characteristics and applications of energy-selected electron imaging at high-resolution for structure determinations are illustrated. It is shown that image contrast can be dramatically improved with the use of an energy filter. High-resolution chemical-sensitive imaging using ionization-loss electrons is demonstrated in studies of Ni/Ti and Al/Ti multilayer thin films. It is also shown that the spatial resolution of energy-selected ionization edge electron images is dominated by the signal-to-noise ratio. Experimental parameters which may be selected to improve the signal-to-noise ratio are discussed.

Extended aortic arch anastomosis for repair of coarctation in infancy

Surgical repair of coarctation of the aorta was performed in 17 infants, median age 14 days, median weight 3.5 kg. Extended end-to-end aortic arch anastomosis was used. A long incision was made in the inferior aspect of the aortic isthmus and arch, which was then anastomosed to the obliquely trimmed distal aorta. The aortic arch was hypoplastic in eight patients. Mean cross-clamp time was 17.1 min. Pulmonary artery bands were placed in five patients. Follow-up two-dimensional echocardiographic and Doppler studies on 13 patients 1 to 56 months after surgery demonstrated normal distal aortic flow in 10, slightly decreased flow in two, and diminished flow in one. Patients with abnormal Doppler flow showed no gradient in one case and a 30 mm Hg gradient in two. Extended aortic arch anastomosis is safe in infancy, leaves no native coarctation shelf tissue in the repaired segment, does not sacrifice the subclavian artery, is useful in hypoplastic isthmus, and is at low risk to develop aneurysm or recoarctation.