Respiratory Management of Patients With Neuromuscular Weakness: An American College of Chest Physicians Clinical Practice Guideline and Expert Panel Report

BACKGROUND

Respiratory failure is a significant concern in neuromuscular diseases (NMDs). This CHEST guideline examines the literature on the respiratory management of patients with NMD to provide evidence-based recommendations.

STUDY DESIGN AND METHODS

An expert panel conducted a systematic review addressing the respiratory management of NMD and applied the Grading of Recommendations, Assessment, Development, and Evaluations approach for assessing the certainty of the evidence and formulating and grading recommendations. A modified Delphi technique was used to reach a consensus on the recommendations.

RESULTS

Based on 128 studies, the panel generated 15 graded recommendations, one good practice statement, and one consensus-based statement.

INTERPRETATION

Evidence of best practices for respiratory management in NMD is limited and is based primarily on observational data in amyotrophic lateral sclerosis. The panel found that pulmonary function testing every 6 months may be beneficial and may be used to initiate noninvasive ventilation (NIV) when clinically indicated. An individualized approach to NIV settings may benefit patients with chronic respiratory failure and sleep-disordered breathing related to NMD. When resources allow, polysomnography or overnight oximetry can help to guide the initiation of NIV. The panel provided guidelines for mouthpiece ventilation, transition to home mechanical ventilation, salivary secretion management, and airway clearance therapies. The guideline panel emphasizes that NMD pathologic characteristics represent a diverse group of disorders with differing rates of decline in lung function. The clinician's role is to add evaluation at the bedside to shared decision-making with patients and families, including respect for patient preferences and treatment goals, considerations of quality of life, and appropriate use of available resources in decision-making.

Factors Associated With Discontinuation of Tuberculosis Preventive Treatment: Post Hoc Analysis of 2 Randomized, Controlled Trials

BACKGROUND

Adherence to tuberculosis preventive treatment (TPT) is an important determinant of clinical benefit. We assessed the association of participant behaviors early in TPT with subsequent discontinuation.

METHODS

We used data from a phase 3 randomized trial and the preceding phase 2 trial to compare 4 months of rifampin to 9 months of isoniazid for TPT. We excluded participants whose providers discontinued TPT due to adverse events or tuberculosis disease. We analyzed 4 outcomes: discontinuing TPT within the first month of treatment, discontinuing TPT between the first and second month, discontinuing TPT after the second month, and completing treatment but not per protocol. We analyzed the association of outcomes with regimen and participant characteristics and 4 behavioral predictors of discontinuation recorded at the month 1 and month 2 follow-up visits: reporting symptoms of intolerance, missing >20% of doses, rescheduling appointments, and not bringing their medication bottle.

RESULTS

Overall, 6656 participants were included (phase 3, 5848; phase 2, 808), of whom 4318 (64.9%) completed treatment per protocol. Participant characteristics were inconsistently associated with discontinuation. Phase 3 trial participants with 1, 2, or 3-4 behavioral predictors at the month 1 follow-up had 5.0 (95% confidence interval, 3.6-6.7), 18.6 (13.3-26.1), and 79.4 (38.2-165.0), respectively, higher odds of discontinuing before the second month. The corresponding number of predictors at the month 2 follow-up had 1.8 (1.4-2.2), 4.7 (3.6-6.2), and 7.4 (4.6-11.9) higher odds of discontinuing before completing treatment; phase 2 findings were similar.

CONCLUSIONS

Four behavioral predictors recorded early in therapy were more strongly associated with subsequent discontinuation than participant characteristics, particularly when more than 1 behavioral predictor was recorded. Clinical Trials Registration. NCT00170209; NCT00931736.

Chronic tracheostomy care of ventilator-dependent and -independent children: Clinical practice patterns of pediatric respirologists in a publicly funded (Canadian) healthcare system

OBJECTIVES

To describe the current clinical practice patterns of Canadian pediatric respirologists at pediatric tertiary care institutions regarding chronic tracheostomy tube care and management of home invasive ventilation.

METHODS

A pediatric respirologist/pediatrician with expertise in tracheostomy tube care and home ventilation was identified at each Canadian pediatric tertiary care center to complete a 59-item survey of multiple choice and short answer questions. Domains assessed included tracheostomy tube care, caregiver competency and home monitoring, speaking valves, medical management of tracheostomy complications, decannulation, and long-term follow-up.

RESULTS

The response rate was 100% (17/17) with all Canadian tertiary care pediatric centers represented and heterogeneity of practice was observed in all domains assessed. For example, though most centers employ Bivona™ (17/17) and Shiley™ (15/17) tracheostomy tubes, variability was observed around tube change, re-use, and cleaning practices. Most centers require two trained caregivers (14/17) and recommend 24/7 eyes on care and oxygen saturation monitoring. Discharge with an emergency tracheostomy kit was universal (17/17). Considerable heterogeneity was observed in the timing and use of speaking valves and speech-language assessment. Inhaled anti-pseudomonal antibiotics are employed by most centers (16/17) though the indication, agent, and protocol varied by center. Though decannulation practices varied considerably, the requirement of upper airway patency was universally required to proceed with decannulation (17/17) independent of ongoing ventilatory support requirements.

CONCLUSION

Considerable variability in pediatric tracheostomy tube care practice exists across Canada. These results will serve as a starting point to standardize and evaluate tracheostomy tube care nationally.

Understanding the experiences of lung volume recruitment among boys with Duchenne muscular dystrophy: A multicenter qualitative study

BACKGROUND

Despite recommendations for regular lung volume recruitment (LVR) use in clinical practice guidelines for children with neuromuscular disease, adherence to LVR is poor. We aimed to describe the experience of LVR by boys with Duchenne muscular dystrophy (DMD), their families, and healthcare providers (HCPs), as well as to identify the barriers and facilitators to LVR use.

METHODS

This multicenter, qualitative study evaluated boys with DMD (n = 11) who used twice-daily LVR as part of a randomized controlled trial, as well as their parents (n = 11), and HCPs involved in the clinical use of LVR (n = 9). Semistructured interviews were conducted to identify participants' understanding of LVR therapy and their beliefs, barriers and facilitators to its use. Thematic analysis was conducted using an inductive approach. A subanalysis compared adherent and nonadherent children.

RESULTS

Seven themes were identified related to participants' beliefs and experiences with LVR: emotional impact, adaptation to LVR, perceived benefits of LVR, routine, family engagement, clinical resources, and equipment-related factors. Strategies to improve adherence were also identified, including education, reinforcement and demonstration of LVR benefit, as well as clinician support. There were no thematic differences between adherent and nonadherent children.

DISCUSSION

Despite the benefits of LVR and positive experiences with it by many families, there remain barriers to adherence to treatment. HCPs need to balance the need for early introduction to give families time to adapt to LVR while ensuring that the benefit of LVR outweighs the burden. Clinician support is important for family engagement.

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.

The utility of echocardiography and pulmonary function testing in the preoperative evaluation of pectus excavatum

PURPOSE

Echocardiography (ECHO) and pulmonary function testing (PFT) are routinely performed during the preoperative evaluation of pectus excavatum (PE). We hypothesized that these investigations may be performed selectively based on patient symptoms and pectus severity.

METHODS

A retrospective review of all PE patients who underwent a Nuss procedure during a 15-year period (2004-2018) was conducted. Symptoms, clinical characteristics, ECHO, and PFT results were extracted from the medical chart. PE severity on computed tomography was measured using the Haller Index (HI) and Correction Index (CI), and reported as mean ± SEM. Logistic and linear regression assessed the ability of symptoms and indices to predict abnormal cardiopulmonary test results.

RESULTS

Of 119 patients, 116 patients had symptom documentation, and 74 (64%) had one or more symptoms. HI and CI were 3.8 ± 1.0 and 31.6 ± 10.3, respectively. Of those with ECHO available (111), 14 (13%) were abnormal, and 12 of 14 required cardiology follow-up. Of those with PFT available (90), the results were abnormal in 15 (17%), including 9 (11%) obstructive, 4 (5%) restrictive, and 2 (2%) mixed. The presence of symptoms did not predict abnormal ECHO or PFT, but each standard deviation increase in the CI was associated with abnormal PFT and ECHO by a factor of 2.2 and 2.0 respectively. HI severity was only associated with ECHO.

CONCLUSION

The rates of abnormal ECHO and PFT testing in PE patients are low, and do not correlate with symptoms. Routine ECHO is still recommended to detect anomalies requiring follow-up. Elevated CI severity may be used to guide selective PFT testing.

LEVELS OF EVIDENCE

Retrospective Study, Level III.

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.

Routine lung volume recruitment in boys with Duchenne muscular dystrophy: a randomised clinical trial

BACKGROUND

Impaired cough results in airway secretion retention, atelectasis and pneumonia in individuals with Duchenne muscular dystrophy (DMD). Lung volume recruitment (LVR) stacks breaths to inflate the lungs to greater volumes than spontaneous effort. LVR is recommended in DMD clinical care guidelines but is not well studied. We aimed to determine whether twice-daily LVR, compared with standard of care alone, attenuates the decline in FVC at 2 years in boys with DMD.

METHODS

In this multicentre, assessor-blinded, randomised controlled trial, boys with DMD, aged 6-16 years with FVC >30% predicted, were randomised to receive conventional treatment or conventional treatment plus manual LVR twice daily for 2 years. The primary outcome was FVC % predicted at 2 years, adjusted for baseline FVC % predicted, age and ambulatory status. Secondary outcomes included change in chest wall distensibility (maximal insufflation capacity minus FVC) and peak cough flow.

RESULTS

Sixty-six boys (36 in LVR group, 30 in control) were evaluated (median age (IQR): 11.5 years (9.5-13.5), median baseline FVC (IQR): 85% predicted (73-96)). Adjusted mean difference in FVC between groups at 2 years was 1.9% predicted (95% CI -6.9% to 10.7%; p=0.68) in the direction of treatment benefit. We found no differences in secondary outcomes.

CONCLUSION

There was no difference in decline in FVC % predicted with use of twice-daily LVR for boys with DMD and relatively normal lung function. The burden associated with routine LVR may outweigh the benefit. Benefits of LVR to maintain lung health in boys with worse baseline lung function still need to be clarified.

TRIAL REGISTRATION NUMBER

NCT01999075.

Pediatric tracheostomy tube decannulation with or without polysomnography: A PRO-CON debate

Determining the timing for decannulation in children with a tracheostomy is a complex process, as the appropriate timing varies based on the initial indication for the tracheostomy tube as well as individual patient characteristics. The original condition for which a tracheostomy was created may improve over time with decannulation being a very important long-term goal for many families and multidisciplinary teams. However, decannulation is an inherently risky procedure associated with morbidity and mortality. Therefore, careful planning is required to ensure the safety of the procedure. Although routine airway endoscopy is an important component of decannulation protocols, guidelines are less prescriptive regarding the definition of a complete endoscopic airway evaluation and the routine use of polysomnography. This review will summarize the important PRO and CON arguments of integrating polysomnography into pediatric decannulation protocols.

Respiratory prehabilitation in pediatric anesthesia in children with muscular and neurologic disease

Children with neuromuscular, chronic neurologic, and chest wall diseases are at increased risk of postoperative respiratory complications including atelectasis, pneumonia, and respiratory failure with the possible need for reintubation or even tracheostomy. These complications negatively impact patient outcomes, including increased healthcare resource utilization and increased surgical mortality. In these children, the existing respiratory reserve is often inadequate to withstand the stresses brought on during anesthesia and surgery. A thorough clinical assessment and objective evaluation of pulmonary function and gas exchange can help identify which children are at particular risk for poor postoperative outcomes and thus merit preoperative interventions. These may include initiation and optimization of non-invasive ventilation and mechanical insufflation-exsufflation. Furthermore, such an evaluation will help identify children who may require a postoperative extubation plan tailored to neuromuscular diseases. Such strategies may include avoidance of pre-extubation lung decruitment by precluding continuous positive airway pressure trials, aggressively weaning to room air and directly extubating to non-invasive ventilation with a high inspiratory to expiratory pressure differential of at least 10 cm H20. Children with cerebral palsy and other neurodegenerative or neurodevelopmental disorders are a more heterogeneous group of children who may share some operative risk factors with children with neuromuscular disease; they may also be at risk of sleep-disordered breathing, may also require non-invasive ventilation or mechanical insufflation-exsufflation, and may have associated chronic lung disease from aspirations that may require perioperative treatment.

Epidemiology, clinical features and outcomes of incident tuberculosis in children in Canada in 2013-2016: results of a national surveillance study

PURPOSE

Childhood tuberculosis disease is difficult to diagnose and manage and is an under-recognised cause of morbidity and mortality. Reported data from Canada do not focus on childhood tuberculosis or capture key epidemiologic, clinical and microbiologic details. The purpose of this study was to assess demographics, presentation and clinical features of childhood tuberculosis in Canada.

METHODS

We conducted prospective surveillance from 2013 to 2016 of over 2700 paediatricians plus vertical tuberculosis programmes for incident tuberculosis disease in children younger than 15 years in Canada using the Canadian Paediatric Surveillance Program (CPSP).

RESULTS

In total, 200 cases are included in this study. Tuberculosis was intrathoracic in 183 patients of whom 86% had exclusively intrathoracic involvement. Central nervous system tuberculosis occurred in 16 cases (8%). Fifty-one per cent of cases were hospitalised and 11 (5.5%) admitted to an intensive care unit. Adverse drug reactions were reported in 9% of cases. The source case, most often a first-degree relative, was known in 73% of cases. Fifty-eight per cent of reported cases were Canadian-born Indigenous children. Estimated study rates of reported cases (per 100 000 children per year) were 1.2 overall, 8.6 for all Indigenous children and 54.3 for Inuit children.

CONCLUSION

Childhood tuberculosis may cause significant morbidity and resource utilisation. Key geographies and groups have very high incidence rates. Elimination of childhood tuberculosis in Canada will require well-resourced community-based efforts that focus on these highest risk groups.

Validation of home portable monitoring for the diagnosis of sleep-disordered breathing in adolescents and adults with neuromuscular disorders

STUDY OBJECTIVES

Sleep-disordered breathing (SDB) is common in patients with neuromuscular disorders (NMD), developing before chronic hypercapnia appears. Polysomnography (PSG) is the diagnostic gold standard but is often impractical and poorly accessible for individuals with NMD. We sought to determine the diagnostic accuracy, feasibility, and patient preference of home sleep apnea testing (HSAT) compared with PSG for the detection of SDB in NMD.

METHODS

Participants with NMD at risk for SDB aged ≥ 13 years underwent HSAT followed by overnight PSG with concomitant laboratory sleep apnea testing (same device as HSAT). Sensitivity and specificity were calculated for standard apnea-hypopnea index cutoffs for mild (≥ 5 events/h), moderate (≥ 15 events/h), and severe SDB (≥ 30 events/h) and for an oxygen desaturation index ≥ 5 events/h. Receiver operating characteristic curves were built. A questionnaire assessed patient preference.

RESULTS

Of 38 participants, 73% had moderate to severe SDB and 79% had technically acceptable HSAT. For an apnea-hypopnea index ≥ 15 events/h, HSAT sensitivity and specificity were 50% and 88%, respectively. For an oxygen desaturation index ≥ 5 events/h, HSAT sensitivity and specificity were 95% and 78%, respectively. The area under the receiver operating characteristic curve for an apnea-hypopnea index ≥ 15 events/h was 0.88 (95% confidence interval, 0.69-1.00) for HSAT. The HSAT underestimated the apnea-hypopnea index from PSG (bias, -10.7 ± 15.9 events/h). HSAT was preferred to PSG by 61% of participants.

CONCLUSIONS

HSAT is feasible, preferred by patients, and reliable for detecting SDB in most patients, although it cannot definitively rule out SDB. Therefore, HSAT is a viable diagnostic approach for SDB in NMD when PSG is not feasible, recognizing that it does not accurately distinguish between upper-airway obstruction and hypoventilation. Additional work is needed to further optimize home sleep testing in NMD.

CITATION

Westenberg JN, Petrof BJ, Noel F, et al. Validation of home portable monitoring for the diagnosis of sleep-disordered breathing in adolescents and adults with neuromuscular disorders. J Clin Sleep Med. 2021;17(8):1579-1590.

Noninvasive Ventilation Downloads and Monitoring

"Home noninvasive ventilation (NIV) is indicated for numerous conditions including neuromuscular disease, thoracic cage disorders, chronic obstructive pulmonary disease, and hypoventilation syndromes. Effective management of patients on home NIV requires clinicians to interpret data downloads from NIV devices. Clinicians must first look at adherence and factors that may impact this including mask comfort and fit. Next, leak assessment is undertaken. Once these are addressed, such information as apnea-hypopnea index, exhaled tidal volume, and percent triggered breaths help clinicians troubleshoot setting changes. Finally, overnight oximetry and transcutaneous CO2 monitoring are useful adjuncts to the data download to optimize NIV settings."

Safety and Side Effects of Rifampin versus Isoniazid in Children

BACKGROUND

The treatment of latent infection with Mycobacterium tuberculosis is important in children because of their vulnerability to life-threatening forms of tuberculosis disease. The current standard treatment - 9 months of isoniazid - has been associated with poor adherence and toxic effects, which have hampered the effectiveness of the drug. In adults, treatment with 4 months of rifampin has been shown to be safer and to have higher completion rates than 9 months of isoniazid.

METHODS

In this multicenter, open-label trial, we randomly assigned 844 children (<18 years of age) with latent M. tuberculosis infection to receive either 4 months of rifampin or 9 months of isoniazid. The primary outcome was adverse events of grade 1 to 5 that resulted in the permanent discontinuation of a trial drug. Secondary outcomes were treatment adherence, side-effect profile, and efficacy. Independent review panels whose members were unaware of trial-group assignments adjudicated all adverse events and progression to active tuberculosis.

RESULTS

Of the children who underwent randomization, 829 were eligible for inclusion in the modified intention-to-treat analysis. A total of 360 of 422 children (85.3%) in the rifampin group completed per-protocol therapy, as compared with 311 of 407 (76.4%) in the isoniazid group (adjusted difference in the rates of treatment completion, 13.4 percentage points; 95% confidence interval [CI], 7.5 to 19.3). There were no significant between-group differences in the rates of adverse events, with fewer than 5% of the children in the combined groups with grade 1 or 2 adverse events that were deemed to be possibly related to a trial drug. Active tuberculosis, including 1 case with resistance to isoniazid, was diagnosed in 2 children in the isoniazid group during 542 person-years of follow-up, as compared with no cases in the rifampin group during 562 person-years (rate difference, -0.37 cases per 100 person-years; 95% CI, -0.88 to 0.14).

CONCLUSIONS

Among children under the age of 18 years, treatment with 4 months of rifampin had similar rates of safety and efficacy but a better rate of adherence than 9 months of treatment with isoniazid. (Funded by the Canadian Institutes of Health Research and Conselho Nacional de Pesquisa; ClinicalTrials.gov number, NCT00170209 .).

Methacholine challenge test: Comparison of tidal breathing and dosimeter methods in children

INTRODUCTION

Methacholine Challenge Test (MCT) is used to confirm, assess the severity and/or rule out asthma. Two MCT methods are described as equivalent by the American Thoracic Society (ATS), the tidal breathing and the dosimeter methods. However, the majority of adult studies suggest that individuals with asthma do not react at the same PC₂₀ between the two methods. Additionally, the nebulizers used are no longer available and studies suggest current nebulizers are not equivalent to these. Our study investigates the difference in positive MCT tests between three methods in a pediatric population.

METHODS

A retrospective, chart review of all MCT performed with spirometry at the Montreal Children's Hospital from January 2006 to March 2016. A comparison of the percentage positive MCT tests with three methods, tidal breathing, APS dosimeter and dose adjusted DA-dosimeter, was performed at different cutoff points up to 8 mg/mL.

RESULTS

A total of 747 subjects performed the tidal breathing method, 920 subjects the APS dosimeter method, and 200 subjects the DA-dosimeter method. At a PC₂₀ cutoff ≤4 mg/mL, the percentage positive MCT was significantly higher using the tidal breathing method (76.3%) compared to the APS dosimeter (45.1%) and DA-dosimeter (65%) methods (P < 0.0001).

CONCLUSION

The choice of nebulizer and technique significantly impacts the rate of positivity when using MCT to diagnose and assess asthma. Lack of direct comparison of techniques within the same individuals and clinical assessment should be addressed in future studies to standardize MCT methodology in children.

Physician driven variation in the care of children with spinal muscular atrophy type 1

BACKGROUND

Increasing numbers of families are requesting active supportive management for their child with spinal muscular atrophy type 1 (SMA1), leading to longer survival and greater prevalence of affected children. Strong opinions exist among physicians for and against the provision of care measures prolonging life.

OBJECTIVE

To describe current practice in the care of SMA1 in Canada, and explore the factors underlying inter-physician variability.

METHODS

A cross-sectional survey of Canadian hospital-based pediatric neurologists and pediatric respirologists was performed in 2015. Odds ratios and 95% confidence intervals were calculated to compare proportions between groups.

RESULTS

There was a 54% completion rate (99 physicians). Over half of participants believed that a disease modifying therapy was likely within 10 years. Quebec respirologists were 50 times less likely to offer long-term non-invasive ventilation (NIV) than respirologists in other provinces (OR 50.6, 95% CI 2.4-1075.3), and 20 times less likely to discuss tracheostomy with families (OR 20.4, 95% CI 2.0-211.8). High raters of perceived happiness of affected children were more likely to find NIV an acceptable measure for acute (OR 6.7, 95% CI 1.7-26.0) and chronic (OR 13.7, 95% CI 4.0-46.4) respiratory failure and prophylactic use (OR 5.8, 95% CI 2.2-15.6).

CONCLUSION

Physician knowledge, opinions, subjective perception of child happiness, and regional factors, all influence physicians' practices and the shared decision-making process. Parents may not be informed or offered all the services available to their child. Knowledge translation initiatives are needed to enhance SMA1 care. Pediatr Pulmonol. 2017;52:662-668. © 2016 Wiley Periodicals, Inc.

Spatial proximity amplifies valence in emotional memory and defensive approach-avoidance

In urban areas, people often have to stand or move in close proximity to others. The egocentric distance to stimuli is a powerful determinant of defensive behavior in animals. Yet, little is known about how spatial proximity to others alters defensive responses in humans. We hypothesized that the valence of social cues scales with egocentric distance, such that proximal social stimuli have more positive or negative valence than distal stimuli. This would predict enhanced defensive responses to proximal threat and reduced defensive responses to proximal reward. We tested this hypothesis across four experiments using 3-D virtual reality simulations. Results from Experiment 1 confirmed that proximal social stimuli facilitate defensive responses, as indexed by fear-potentiated startle, relative to distal stimuli. Experiment 2 revealed that interpersonal defensive boundaries flexibly increase with aversive learning. Experiment 3 examined whether spatial proximity enhances memory for aversive experiences. Fear memories for social threats encroaching on the body were more persistent than those acquired at greater interpersonal distances, as indexed by startle. Lastly, Experiment 4 examined how egocentric distance influenced startle responses to social threats during defensive approach and avoidance. Whereas fear-potentiated startle increased with proximity when participants actively avoided receiving shocks, startle decreased with proximity when participants tolerated shocks to receive monetary rewards, implicating opposing gradients of distance on threat versus reward. Thus, proximity in egocentric space amplifies the valence of social stimuli that, in turn, facilitates emotional memory and approach-avoidance responses. These findings have implications for understanding the consequences of increased urbanization on affective interpersonal behavior.

HER2 staining intensity in HER2-positive disease: relationship with FISH amplification and clinical outcome in the HERA trial of adjuvant trastuzumab

BACKGROUND

Trastuzumab treatment improves survival of HER2-positive primary breast cancer. HER2 staining intensity varies widely in HER2-positive tumours.

PATIENTS AND METHODS

We investigated whether differences in immunohistochemical (IHC) staining intensity for HER2 in HER2-positive tumors (IHC 3+ or FISH ratio ≥2.0) was associated with prognosis or benefit from trastuzumab treatment in patients randomized to 1 year or no trastuzumab in the HERceptin Adjuvant (HERA) trial. Median follow-up was 2 years. The nested case-control analysis, included 425 patients (cases) with a disease-free survival (DFS) event and two matched controls (no DFS event) per case. Tissue sections stained for HER2 were assessed for HER2 staining intensity by image analysis.

RESULTS

HER2 staining intensity varied widely and correlated with HER2 gene copy number (Spearman, r = 0.498, P < 0.001) or less closely with HER2/CEP17 FISH ratio (r = 0.396, P < 0.001). We found no significant difference in DFS in the observation arm according to staining intensity (odds ratio [OR] change per 10 unit change in intensity: 1.015, 95% confidence interval [CI] 0.930-1.108) and no impact of staining intensity on benefit derived from 1-year trastuzumab (OR: 1.017, 95% CI 0.925-1.120).

CONCLUSIONS

Variability in HER2 staining in HER2-positive tumours has no role in clinical management with adjuvant trastuzumab.

HERA TRIAL NO

NCT00045032.

Transcriptional profiling of transurethral resection samples provides insight into molecular mechanisms of hormone refractory prostate cancer

The molecular mechanisms for hormone-resistant prostate cancer progression still remain elusive, mainly due to the limited availability of corresponding tissue. As transurethral resection (TUR) is a common palliative therapy for patients with hormone refractory prostate cancer (HRPC) who have subvesical obstruction, we aimed to demonstrate that TUR samples can be used to identify significantly affected biological pathways during the switch to HRPC using oligonucleotide microarray analysis. Among the most significantly deregulated pathways in HRPC, we observed an induction of oxidative phosphorylation and a repression of cytoskeletal components.

Molecular analysis of hormone refractory prostate cancer biopsies supports the rationale of using mTOR inhibitors

21126

Background: The aim of our group is to identify molecular signatures in samples of hormone refractory prostate cancer (HRPC) patients (pts) that lead to novel rationales for medical treatment. We have previously shown that transurethral resections (TUR) of the prostate in HRPC pts are useful specimens for gene expression profiling using microarrays (ASCO 2006). Aim of this study was to prove the feasibility of gene expression profiling on prostate biopsies and to develop a standardised tissue handling protocol in order to facilitate multicenter research. Methods: Biopsy material and corresponding TUR chips or classical specimens from 8 pts with HRPC, 13 pts with localized PCA, 6 pts with benign prostatic hyperplasia (BPH) and 11 pts without cancer or BPH were investigated and compared. The tumor type and content was evaluated by a pathologist. Tissues were preserved in liquid nitrogen or RNAlater. Different tissue lysis and RNA purification methods were compared by the quantity (NanoDrop measurement) and quality (Bioanalyser, Agilent) of isolated RNA. Gene expression profiling occurred on Affymetrix HG-FOCUS arrays. Results: Most reliable gene expression results were obtained by biopsy lysis in Trizol using the QIAshredder. A total of more than 1 μg RNA was isolated from one biopsy. RNA quality fulfilled pre-defined criteria such as a 28S/18S rRNA ratio of > 0.8, an area under the curve of > 10% and a RNA integrity number > 6.5. A comparison of HRPC and PCA samples clearly confirmed previous results of a deregulation of protein biosynthesis (translation initiation and elongation factors, ribosome biogenesis) and PI3K signalling pathway components. Conclusions: Gene expression profiling supports the induction of the PI3K-AKT-mTOR pathway in HRPC. A standardised protocol for gene expression profiling from prostate biopsy samples applicable for translational research programs within multicenter clinical trials is now available. As a part of a clinical phase II trial that aims to investigate survival benefits on HRPC pts treated with docetaxel ± RAD001, a translational research program is now set up in parallel to identify biomarkers for response prediction using microarray gene expression analysis from prostate biopsies.

No significant financial relationships to disclose.

Validation of a flow cytometric acridine orange micronuclei methodology in rats

Our laboratory has previously reported a flow cytometric acridine orange method for detection of micronucleus (MN) in the rat using cyclophosphamide as a test compound. To replace the manual method of scoring and satisfy Good Laboratory Practice (GLP) requirements, an extensive validation of the flow method was required. Therefore, manual scoring and flow cytometric determination of MN were compared using vincristine, chlorambucil, methotrexate, and doxorubicin compounds known to induce MN formation with various mechanisms of action. 1,2-Dimethylhydrazine (1,2-DH), a compound with negative or equivocal MN findings also was evaluated. The flow method consistently demonstrated dose- and time-dependent responses for MN production at all concentrations of vincristine, methotrexate, clorambucil, and doxorubicin. In contrast, manual scoring of slides failed to detect an increase in MN at the lowest doses of doxorubicin (1mg/kg) at 24 or 48 h, and methotrexate at 48 h, or any dose of methotrexate (50, 100, or 250 mg/kg) at 24h. Additionally, a dose-response for methotrexate at 48 h, and chlorambucil at 24 h were missed using manual scoring. For 1,2-DH, the flow method showed a low level (< 1.4-fold) increase in MN at all doses and times. In contrast, the manual method showed five-seven-fold increases at 24 h, but a < two-fold increase at 48 h in the highest dose only. These data may suggest that the flow method has a greater sensitivity and possibly accuracy than manual scoring. Significant decreases in polychromatic erythrocytes (PCE) were seen using both methods at approximately the same dose for all compounds. However, absolute flow cytometric PCE values were consistently higher than manual. Additional cytotoxicity parameters obtained by the flow method allowed a more complete assessment of cytotoxicity than PCE alone. Furthermore, data reported here combined with improved throughput, shortened data turnaround and reporting times, and possibly better precision due to evaluation of much larger numbers of cells clearly demonstrate the usefulness of flow cytometry method in the routine micronucleus evaluation.

Child maltreatment and the early onset of problem behaviors: can a program of nurse home visitation break the link?

This study investigated the relationship between child maltreatment and the early onset of problem behaviors in the Elmira Nurse Home Visitation Program. Participants were predominantly low-income and unmarried mothers and their first-born children who were randomized either to receive over 2 years of home-visitation services by nurses or to be placed in a comparison group. Data were drawn from a follow-up study that took place when the children were 15 years of age. Results demonstrated that, in the comparison group. child maltreatment was associated with significant increases in the number of early onset problem behaviors reported by the youth. For the youth in the nurse-visited group there was no relationship between maltreatment and early onset problem behaviors. We suggest that this finding was due to the effects of the intervention in reducing the number as well as the developmental timing of the maltreatment incidents. Results suggest that prenatal and infancy home visiting by nurses can moderate the risk of child maltreatment as a predictor of conduct problems and antisocial behavior among children and youth born into at-risk families.

A simplified and reliable HPV testing of archival Papanicolaou-stained cervical smears: application to cervical smears from cancer patients starting with cytologically normal smears

The efficacy of four methods to recover DNA from Papanicolaou (Pap)-stained archival cervical smears for optimal detection of human papillomavirus (HPV) DNA by GP5+/bioGP6+ polymerase chain reaction (PCR) was investigated. Two of the methods were based on proteinase K treatment and two based on treatment with guanidinium thiocyanate (GTC). The quality of the DNA as measured by PCR assays amplifying different sizes of the beta-globin gene appeared to be superior for the GTC-based assays. Using competitive beta-globin PCR assays, one of the GTC-based, assays, provisionally named High Pure PCR Template Preparation (HPPTP) assay, yielded by far the highest quantity of amplifiable DNA. It allowed the recovery of 2.2 x 10(5) to 3 x 10(5) genome equivalents in smears containing 5 x 10(5) to 20 x 10(5) nucleated cells, indicating a mean efficiency of 26% (range of 15-44%). In contrast, the other methods revealed markedly lower efficiencies varying from 1% to 10%. The use of the HPPTP assay as a reliable processing procedure was validated by demonstrating a complete agreement in HPV detection and 93% agreement in HPV typing between 39 archival Pap-stained and paired fresh-frozen cervical smears. This method was applied to 40 archival smears from ten cervical cancer patients (selected from a group of 200 patients) which had a history of 3-6 smears with the first smear being Pap 1 or 2 taken at least 5 years before cancer was diagnosed. The average time period between the first Pap 1/2 smear that contained the same HPV type as in the corresponding carcinoma and diagnosis of cervical cancer was 12.0 +/- 2.9 years. All subsequent smears were invariably positive for the same HPV type which was also found in the cervical cancer biopsy. In conclusion, the HPPTP assay provides a reliable and efficient means to extract DNA from Pap-stained archival cervical smears for the detection of HPV DNA by PCR and would be the method of choice for future HPV analysis of archival Pap-stained cervical smears.

Use of acridine orange in: flow cytometric evaluation of erythropoietic cytotoxicity

Cytotoxic insult to bone marrow frequently impairs the proliferating and maturational abilities of erythroid cells. Typically, a ratio of enucleated, immature polychromatic erythrocytes (PCE) to mature normochromatic erythrocytes (NCE) is used to assess cytotoxicity in the micronucleus (MN) assay. The effects of cyclophosphamide (CP) on PCE/NCE ratio in rat bone marrow and spleen were assessed by a newly developed flow cytometric procedure using glutaraldehyde-fixed, acridine orange (AO)-stained cells, and compared to manual scoring of PCE/NCE in Wright stained slides. Comparison of methods showed that manual and flow cytometric determination of PCE were not statistically different. Several other parameters of cytotoxicity could be simultaneously assessed because the method allowed use of unfractionated whole bone marrow/spleen cell samples. Absolute numbers of total nucleated cells (TNC), a ratio of TNC to total erythrocytes (TE), and determination of RNA content within the PCE population demonstrated dose- and time-dependent effects with CP treatment. Shifts in RNA content were particularly sensitive, correctly identifying all CP-treated from control specimens, even in those samples where PCE/NCE ratio was similar. The AO methodology provided a more rapid, statistically-superior, and thorough approach in the assessment of bone marrow and spleen cytotoxicity than the conventional manual method of scoring PCE/NCE ratio alone.

Use of acridine orange in: flow cytometric assessment of micronuclei induction

The micronucleus assay is a widely accepted method for evaluation of clastogens and aneugens. In the current study, acridine orange (AO) supravital staining was adapted for flow cytometric usage to assess micronucleated cells in rat bone marrow and spleen. Cyclophosphamide was used as a positive control test compound and results were compared to manual scoring in Wright-stained slides. In bone marrow, both manual and flow cytometric methods demonstrated positive dose response-trends for micronucleated polychromatic erythrocytes (MNPCE). Significant elevations in MNPCE were observed at all doses of cyclophosphamide, and comparisons between methods in bone marrow were not statistically different. The flow cytometric method was more sensitive in spleen samples, showing dose- and time-related increases in micronuclei compared with manual scoring. AO proved to be a sensitive discriminator of RNA and DNA, allowing distinct separation of polychromatic erythrocytes (PCE), normochromic erythrocytes (NCE), total nucleated cells (TNC), and micronucleated populations within both PCE and NCE regions. These results support the use of AO-based flow cytometry to provide a rapid and sensitive indicator of micronuclei inducers.

Flow cytometric evaluation of bone marrow differentials in rats with pharmacologically induced hematologic abnormalities

Previously, flow cytometric determination of peroxidase activity, cell size, and reactivity to lymphocyte antibodies were used to produce bone marrow differentials in untreated rats. In the present study, abnormal hematologic profiles were induced with erythropoietin (EPO), recombinant murine stem cell factor (rm-SCF), granulocyte-macrophage stimulating factor (GM-CSF), and cyclophosphamide (CP). Manual and flow cytometric data showed comparable levels of erythroid and myeloid hyperplasia in EPO- and rm-SCF/GM-CSF-treated animals, respectively. In CP-treated animals, flow cytometric data revealed significant decreases in cellularity at concentrations of CP > or = 5 mg/kg. In contrast, 20 mg/kg CP were necessary to induce microscopically apparent hypoplasia in histologic bone sections, showing that the automated methodology was a more sensitive indicator of bone marrow hypocellularity than was the more conventional manual method. Megakaryocyte counts were consistently higher by flow cytometer than by manual counts performed on cytocentrifuge preparations made from the same cell suspensions but were similar to megakaryocyte counts performed on histologic sections of femur, indicating that the automated methodology produced a more accurate reflection of true megakaryocyte numbers. Induction of hematologic abnormalities in the present study showed that manual bone marrow differentials can be replaced with the more efficient and reliable flow cytometric method in most preclinical toxicology studies.

Comparison of flow cytometric and manual bone marrow differentials in Wistar rats

Preclinical drug trials frequently require the evaluation of animal bone marrow, a time-consuming process requiring the skills of a highly trained hematologist. In the present study, a flow cytometric technique was developed that could effectively replace the need for manual bone marrow differentials in rats. Peroxidase activity, measured indirectly with 2'7'-dichlorofluorescein, was coupled with the use of species-specific T- and B-lymphocyte antibodies and cell size to produce a flow cytometric analysis of rat bone marrow. Accurate identification of lymphocyte, proliferating and maturing erythroid and myeloid, and megakaryocyte populations was confirmed by cell sorting. Flow cytometry yielded differentials that were indistinguishable from manual differentials and published reference ranges. Enumeration of lymphocyte numbers with monoclonal markers is a key advantage of flow cytometric differentials because misidentification of lymphocytes in poorly prepared or stained bone marrow smears is a common problem. The most apparent advantage is increased throughput and reproducibility. Operator training for analysis using flow cytometry can be readily accomplished within a few days as opposed to the extensive training required for individuals performing manual bone marrow differentials. This methodology provides a high-volume, rapid, and relatively low-cost tool for the reliable evaluation of rat bone marrow differentials that has been heretofore unavailable.

[Risk factors for squamous epithelial carcinoma of the mouth, the oropharynx, the hypopharynx and the larynx]

This case-control-study, carried out in two University clinics, comprised 200 men (mean age 57.5 +/- 10.8 [range 33-89] years) with squamous epithelioma of the larynx (44.5%), oral cavity (23.5%), oropharynx (24%) or hypopharynx (8%) and 800 controls. Enquiries were directed at social status, life style and occupational exposure to substances such as asbestos, solvents, wood dust and cement. The peak incidence of these cancers was from 50 to 60 years of age. The proportion of unmarried or divorced men among the cancer patients was more than twice as high as in the controls (25.8% vs 11.8%; P less than 0.001). The proportion of cancer patients who had completed technical college or university education was significantly lower than in the controls (9.6% vs 24.4%; P less than 0.001). Tobacco and alcohol consumption by the cancer patients was roughly twice as great as in the controls: the cancer patients admitted to an average cigarette consumption of 43.2 +/- 27.9 pack years as compared with 20.1 +/- 26.7 pack years for the controls (P less than 0.001), and an alcohol intake of 69.2 +/- 58.1 g/d as compared with 29.8 +/- 27.5 g/d for the controls (P less than 0.001). Both these factors--drinking alcohol and smoking cigarettes--acted independently of one another to raise the relative risk of squamous epithelioma of the upper respiratory or digestive tract. The effects of alcohol and tobacco on cancer risk were multiplicative rather than merely additive. Enquiries into diet failed to reveal any clear differences tending to incriminate any particular food. Long-term exposure to cement dust was linked with an increased risk of cancer.

Assignment of a processed mouse Aprt pseudogene to the same chromosome as the functional gene

A novel genetic system has been used to demonstrate that a processed adenine phosphoribosyltransferase (Aprt) pseudogene is located on mouse chromosome 8, which is the same chromosome that carries the functional Aprt gene. A restriction fragment length polymorphism associated with the pseudogene was found to segregate concordantly with chromosome 8 in APRT- mutants of a near-diploid cell line that had lost one copy of the chromosome.