Current utility of first-line FT4 and TSH in screening for central hypothyroidism.

BACKGROUND: Thyroid testing strategies vary across laboratories. First-line combined thyroid stimulating hormone (TSH) and freeT4 (FT4) have historically been preferred by many laboratories as this detects individuals with undiagnosed central hypothyroidism who can be missed with a first-line TSH-only strategy. However, an up-to-date evaluation of the utility of this approach is lacking. OBJECTIVES: We investigated the clinical utility of first-line TSH and FT4 in the detection of central hypothyroidism in current day practice. DESIGN, PATIENTS, AND MEASUREMENTS: The All-Wales laboratory information system was queried to identify thyroid function tests in patients aged ≥16 years with decreased FT4 and inappropriate TSH (low-FT4). The 1-year incidence of low-FT4 was determined using mid-year population data. Clinical information of patients with low-FT4 was reviewed to determine causes of low-FT4 and the incidence of central hypothyroidism. RESULTS: The incidence of low-FT4 varied according to FT4 assay method (range: 98-301 cases/100,000 population/year). Fifteen new cases of central hypothyroidism were detected in two health boards, equivalent to 2 cases/100,000 population/year. Positive predictive value of low-FT4 for central hypothyroidism was 2%-4%. In a cross-section of primary care patients, low-FT4 was detected in 0.5% of all thyroid tests with assay-related differences in detection rates. CONCLUSIONS: Although low-FT4 is a common laboratory finding, the incidence of central hypothyroidism remains rare. With the currently increased rates of thyroid testing and increased use of medications that decrease FT4, low-FT4 has a much lower predictive value for central hypothyroidism than previously reported. Thyroid screening strategies will need to balance the yield from first line TSH and FT4 testing with the cost of investigating individuals with non-pathological laboratory abnormalities.

Overcoming Barriers to Latino Participation in Alzheimer's Disease Research.

There is a critical need to increase Latino participation in research on Alzheimer's disease and related disorders (ADRD). Applying principles of community-based participatory research, we convened a community advisory board (CAB) to identify barriers and recommend strategies to increase participation of older Latinos in a longitudinal observational research study of ADRD at the Shiley-Marcos Alzheimer's Disease Research Center. Six major barriers were identified and programmatic changes to overcome them were implemented. Changes resulted in a nearly three-fold increase in the number of Latino individuals recruited, with the proportion of all newly recruited participants who were Latino increasing from 12.2% to 57.4%. Newer Latino recruits were more representative of the elderly Latino population in San Diego County than those recruited pre-CAB and remained highly agreeable to blood draw and neuroimaging, though less so to lumbar puncture and autopsy. Results demonstrate the value of CAB involvement in enhancing diversity in ADRD research.

Multi-center evaluation of the highly sensitive Abbott ARCHITECT and Alinity thyroglobulin chemiluminescent microparticle immunoassay.

BACKGROUND: Thyroglobulin (Tg) is an essential part for the management of patients with differentiated thyroid carcinoma (DTC) after thyroidectomy. Highly sensitive Tg assays are now established in clinical practice as they facilitate follow-up of DTC patients. In this study, we evaluated the recently launched highly sensitive Abbott Tg assay for Alinity and ARCHITECT. METHODS: In this three-center study, Tg values of 447 routine patient samples, characterized for the presence of anti-Tg, were measured with the ARCHITECT Tg assay and compared with the Roche Elecsys TgII assay. In addition, a subset of 154 samples was compared also with the Beckman Tg Access assay and another subset (n = 122) with Abbott Tg on the Alinity i analyzer. RESULTS: LoQ was verified to be less than or equal to 0.1 ng/ml confirming that the Tg assay on ARCHITECT and Alinity is highly sensitive. Correlation of ARCHITECT, Alinity, and Roche was excellent with a slope between 0.9 and 1.1 and a correlation coefficient >0.98. Correlation to Beckmann Tg was also very good, but the differences in absolute values were significant (slope: 1.477). CONCLUSIONS: The Abbott Thyroglobulin assay, which is standardized to CRM-457, demonstrated a high correlation to the Roche and Beckman Tg assays, though good agreement of absolute values was only observed between Abbott and Roche. Strength of correlation and slope were not affected by the presence of anti-Tg indicating that all assays included in the study have a similar susceptibility to anti-Tg.

Trauma-informed care with women diagnosed with postpartum depression: a conceptual framework.

Postpartum depression (PPD) is a mental health disorder that affects approximately 20% of all new mothers. PPD frequently co-occurs with and is exacerbated by trauma, particularly for women from vulnerable populations. Trauma-informed care (TIC) is a best practice that recognizes the importance of, and takes steps to promote recovery from, trauma while preventing retraumatization. Despite its potential utility, there is limited research published on TIC, including how TIC is operationalized across practice settings. Further, despite the prevalence and negative effects of untreated PPD, to date there have been limited articles published on TIC and PPD. The purpose of this article is to provide a TIC framework for service delivery for women diagnosed with PPD including explicit strategies for how TIC should be structured across roles, settings, and systems. Implications for health practice, policy, and future research are provided.

Addressing access barriers to services for mothers at risk for perinatal mood disorders: A social work perspective.

This article identifies variables at the micro/individual, mezzo/partner/spouse and family, and macro/health care-system levels that inhibit mothers at risk for perinatal mood disorders from accessing health and mental health care services. Specific recommendations are made for conducting thorough biopsychosocial assessments that address the mothers' micro-, mezzo-, and macro-level contexts. Finally, the authors provide suggestions for how to intervene at the various levels to remove access barriers for mothers living with perinatal mood disorders as well as their families.

Clinical supervision in a community setting.

Clinical supervision is a formal process of professional support, reflection and learning that contributes to individual development. First Community Health and Care is committed to providing clinical supervision to nurses and allied healthcare professionals to support the provision and maintenance of high-quality care. In 2012, we developed new guidelines for nurses and AHPs on supervision, incorporating a clinical supervision framework. This offers a range of options to staff so supervision accommodates variations in work settings and individual learning needs and styles.

Neonatal blood TSH concentration in Wales (UK): an indicator of iodine sufficiency.

OBJECTIVE: Population iodine status can be assessed by urinary iodine concentrations, prevalence of goitre, frequency of newborn thyroid-stimulating hormone (TSH) >5 mU/l and blood thyroglobulin concentrations. The UK population has historically been considered to be iodine sufficient; however, a recent survey of UK schoolgirls has demonstrated median urinary iodine concentrations consistent with mild iodine deficiency. The aim of our study was to assess the prevalence of TSH >5 mU/l in the newborn blood spot screening samples from the eligible population in Wales between 2011 and 2013 to assess iodine sufficiency. MEASUREMENTS: Blood spot TSH data for 104 992 infants during this time period were evaluated. RESULTS: The prevalence of TSH >5 mU/l in samples collected on days 4 and 5 of life were 1·5% and 0·9%, respectively. No increasing trend in blood spot TSH concentration was identified over the 3 years. CONCLUSIONS: The distribution of blood spot TSH data from neonates in Wales has revealed no evidence to support the hypothesis that the population is iodine deficient. However, given that mild iodine deficiency has been reported in a cohort that will be childbearing in the next decade, we recommend that the distribution of neonatal blood spot TSH concentrations is monitored by the UK newborn screening programmes to identify any emerging trends in iodine status. Further studies to correlate maternal urinary iodine and newborn blood spot TSH are required to clarify the TSH cut-off points associated with mild iodine deficiency relevant to the time of blood spot sampling in the UK.

Salivary Cortisol Response to ACTH Stimulation Is a Reliable Alternative to Serum Cortisol in Evaluating Hypoadrenalism.

CONTEXT: The serum total cortisol response to the ACTH stimulation test is widely used to assess adrenocortical function but is affected by changes in cortisol-binding globulin (CBG) concentration. Salivary cortisol reflects free cortisol concentrations and may offer a reliable alternative. OBJECTIVES: (1) To establish the salivary cortisol response to ACTH stimulation in healthy volunteers and patients with altered CBG concentrations; (2) to evaluate the performance of a lower reference limit (LRL) determined in healthy volunteers in patients with suspected hypoadrenalism (SH-patients). DESIGN: A 250 µg ACTH stimulation test was undertaken in 139 healthy volunteers, 24 women taking an estradiol-containing oral contraceptive pill (OCP-females), 10 patients with low serum protein concentration (LP-patients), and 30 SH-patients. Salivary cortisol was measured by liquid chromatography-tandem mass spectrometry. Mean and LRL of the 30-minute salivary cortisol response (mean-1.96 standard deviation) were derived from log-transformed concentrations. The LRL was applied as a diagnostic cut-off in SH-patients, with comparison to the serum response. RESULTS: Mean CBG concentrations (range) were 58 (42-81) mg/L, 64 (43-95) mg/L, 41 (28-60) mg/L, and 116 (84-159) mg/L in males, females, LP-patients, and OCP-females, respectively. The mean 30-minute salivary cortisol concentration was 19.3 (2.5th-97.5th percentile 10.3-36.2) nmol/L in healthy volunteers. Corresponding values were not different in OCP-females [19.7 (9.5-41.2) nmol/L; P = .59] or LP-patients [19.0 (7.7-46.9) nmol/L; P = .97]. Overall diagnostic agreement between salivary and serum responses in SH-patients was 79%. CONCLUSION: Salivary cortisol response to ACTH stimulation offers a reliable alternative to serum and may be especially useful in conditions of altered CBG concentration.

Developing a scale to explore self-regulatory approaches to assessment and feedback with academics in higher education.

Introduction: Students need to acquire high level self-regulatory skills if they are to be successful within higher education, and academics need support in facilitating this. In this article we explore how the current research gap between knowledge of self-regulatory assessment and feedback (SRAF) practices, and academics' professional training in it can be bridged. Methods: SRAF tools were used with academics to explore their understandings of and training needs in SRAF; central to this work was the development of a SRAF scale. We consider the value of such tools in supporting academics' professional development needs in SRAF. The reliability and validity of the SRAF scale was tested using exploratory factor analyses (EFA). Results: Iterative EFA resulted in a 17 item support required SRAF scale (SR). Two underpinning factors: Creating the Conditions for SRAF, and Supporting Students' SRAF Skills Development were identified. The reliability of the instrument supported its primary use as a tool to facilitate academics' professional development in fostering students' self-regulatory skills. Discussion: Our findings highlight the importance of supporting academics in developing strategies to maximize students' metacognitive skills and motivation in assessment and feedback, contingent on effective assessment design. Such professional development needs to be mindful of individual and contextual factors impacting academics' access to, and confidence and competence in, using SRAF in practice. This research is important in highlighting potential disconnects between where academics' focus their attention in assessment, and what is known to have most impact on student learning success. The SRAF tools have considerable potential in supporting translation of theory into practice as part of sustained professional development for academics in higher education.

Method-specific serum cortisol responses to the adrenocorticotrophin test: comparison of gas chromatography-mass spectrometry and five automated immunoassays.

OBJECTIVE: The serum cortisol response to the adrenocorticotrophin (ACTH) test is known to vary significantly by assay, but lower reference limits (LRL) for this response have not been established by the reference gas chromatography-mass spectrometry (GC-MS) method or modern immunoassays. We aimed to compare the normal cortisol response to ACTH stimulation using GC-MS with five widely used immunoassays. DESIGN, PATIENTS AND MEASUREMENTS: An ACTH test (250 µg iv ACTH1-24 ) was undertaken in 165 healthy volunteers (age, 20-66 years; 105 women, 24 of whom were taking an oestrogen-containing oral contraceptive pill [OCP]). Serum cortisol was measured using GC-MS, Advia Centaur (Siemens), Architect (Abbott), Modular Analytics E170 (Roche), Immulite 2000 (Siemens) and Access (Beckman) automated immunoassays. The estimated LRL for the 30 min cortisol response to ACTH was derived from the 2·5th percentile of log-transformed concentrations. RESULTS: The GC-MS-measured cortisol response was normally distributed in males but not females, with no significant gender difference in baseline or post-ACTH cortisol concentration. Immunoassays were positively biased relative to GC-MS, except in samples from women on the OCP, who showed a consistent negative bias. The LRL for cortisol was method-specific [GC-MS: 420 nm; Architect: 430 nm; Centaur: 446 nm; Access 459 nm; Immulite (2000) 474 nm] and, for the E170, also gender-specific (female: 524 nm; male 574 nm). A separate LRL is necessary for women on the OCP. CONCLUSIONS: Normal cortisol responses to the ACTH test are influenced significantly by assay and oestrogen treatment. We recommend the use of separate reference limits in premenopausal women on the OCP and warn users that cortisol measurements in this subgroup are subject to assay interference.

Field independence: reviewing the evidence.

BACKGROUND: The construct of field independence (FI) remains one of the most widely cited notions in research on cognitive style and on learning and instruction more generally. However, a great deal of confusion continues to exist around the definition of FI, its measurement, and the interpretation of research results, all of which have served to limit our understanding of and practice in education. AIMS: This study reviews research evidence on FI and highlights key issues to frame a more informed agenda for future research. ARGUMENTS: Caution needs to be exercised over the interpretation of the evidence around FI and field dependence (FD). In tests measuring FI only, it is inappropriate to use the term FD. FI is clearly correlated with measures of spatial ability; however, whether FI is just a measure of perceptual and more specifically spatial ability is a matter of debate. Furthermore, whether FI is just a cognitive ability or a cognitive style is not the central issue, as both can be developed. FI has a significant relationship with aspects of working memory and with other variables. It is especially important in the management and interpretation of complex cognitive tasks. CONCLUSIONS: Field independence has an important role to play in the navigation of the complex and information-rich learning environments of the 21st century. It is therefore important to move beyond the present narrow focus on FI as a style or trait by acknowledging, embracing, and exploring the complexity of the interaction between individual and contextual variables.

The development and validation of the assessment engagement scale.

Introduction: The quality of student engagement in assessment within higher education affects learning outcomes. However, variations in conceptions of what quality in engagement looks like impacts assessment design and the way that students and lecturers engage with each other in the assessment process. Given that assessment is an important driver of student engagement in higher education, it is surprising that no specific measures to support understanding of this measure exist. To address this significant gap, we outline the evolution of an assessment engagement scale derived from a research-informed conceptual framework utilizing best practice in assessment and feedback. Methods: We consider the validity and utility of the assessment engagement scale in supporting students' understanding of assessment and their role within it using exploratory and confirmatory factor analyses. Results: The resultant nine-item assessment engagement scale's underpinning two factors included: (i) Understanding of the Assessment Context (UAC) including one's role within it, and confidence in navigating assessment requirement, and (ii) Realising Engagement Opportunities (REO) (i.e., willingness to engage and ability to utilise the assessment context effectively to support one's understanding). Construct, criterion, and convergent validity of the scale were established. Discussion: The AES is a powerful tool in promoting dialogue between lecturers and students about what high quality engagement in assessment looks like, and the respective roles of all parties in realising this. Implications for assessment practices are discussed along with the potential of the scale as a predictive and developmental tool to support enhancements in assessment design and student learning outcomes in higher education.

Neonatal plasma TSH--estimated upper reference intervals for diagnosis and follow up of congenital hypothyroidism.

Age- and method-dependent plasma TSH reference intervals are essential for the diagnosis and management of congenital hypothyroidism. However, accurate reference intervals for plasma TSH have not been adequately defined due to the difficulties in obtaining samples from a healthy paediatric population. To overcome the difficulties in generating such intervals we estimated method-dependent plasma TSH upper-reference intervals by determining the blood spot TSH upper-reference interval from newborn blood spot TSH screening data (N = 10,697) and then derived method-dependent conversion factors for blood spot TSH to plasma TSH concentration from paired-blood spot and plasma TSH measurements. The upper reference interval for blood spot TSH of 3.04 mU/L was obtained from the 97.5th centile of the selected data. Using experimentally-derived conversion factors, estimates of plasma TSH upper reference intervals of 7.6, 6.3, 7.3, 8.3 and 6.5 mU/L were obtained for the Siemens Centaur, Abbott Architect, Roche Elecsys E170, Siemens Immulite 2000 and Beckman access HYPERsensitive TSH assays respectively. These estimated method-dependent plasma TSH upper reference intervals will be of great practical use to clinicians to diagnose and to follow up infants found to have increased blood spot TSH concentrations identified by Newborn Screening programmes.

Method-dependent variation in TSH and FT4 reference intervals in pregnancy: A systematic review.

BACKGROUND: Gestational TSH and FT4 reference intervals may differ according to assay method, but the extent of variation is unclear and has not been systematically evaluated. We conducted a systematic review of published studies on TSH and FT4 reference intervals in pregnancy. Our aim was to quantify method-related differences in gestation reference intervals, across four commonly used assay methods, Abbott, Beckman, Roche and Siemens. METHODS: We searched the literature for relevant studies, published between January 2000 and December 2020, in healthy pregnant women without thyroid antibodies or disease. For each study, we extracted trimester-specific reference intervals (2.5-97.5 percentiles) for TSH and FT4 as well as the manufacturer-provided reference interval for the corresponding non-pregnant population. RESULTS: TSH reference intervals showed a wide range of study-to-study differences with upper limits ranging from 2.33 to 8.30 mU/L. FT4 lower limits ranged from 4.40 to 13.93 pmol/L, with consistently lower reference intervals observed with the Beckman method. Differences between non-pregnant and first trimester reference intervals were highly variable, and for most studies, the TSH upper limit in the first trimester could not be predicted or extrapolated from non-pregnant values. CONCLUSIONS: Our study confirms significant intra- and intermethod disparities in gestational thyroid hormone reference intervals. The relationship between pregnant and non-pregnant values is inconsistent and does not support the existing practice in many laboratories of extrapolating gestation references from non-pregnant values. Laboratories should invest in deriving method-specific gestation reference intervals for their population.

Impact of potential modifications to Alzheimer's disease clinical trials in response to disruption by COVID-19: a simulation study.

BACKGROUND: The COVID-19 pandemic disrupted Alzheimer disease randomized clinical trials (RCTs), forcing investigators to make changes in the conduct of such trials while endeavoring to maintain their validity. Changing ongoing RCTs carries risks for biases and threats to validity. To understand the impact of exigent modifications due to COVID-19, we examined several scenarios in symptomatic and disease modification trials that could be made. METHODS: We identified both symptomatic and disease modification Alzheimer disease RCTs as exemplars of those that would be affected by the pandemic and considered the types of changes that sponsors could make to each. We modeled three scenarios for each of the types of trials using existing datasets, adjusting enrollment, follow-ups, and dropouts to examine the potential effects COVID-19-related changes. Simulations were performed that accounted for completion and dropout patterns using linear mixed effects models, modeling time as continuous and categorical. The statistical power of the scenarios was determined. RESULTS: Truncating both symptomatic and disease modification trials led to underpowered trials. By contrast, adapting the trials by extending the treatment period, temporarily stopping treatment, delaying outcomes assessments, and performing remote assessment allowed for increased statistical power nearly to the level originally planned. DISCUSSION: These analyses support the idea that disrupted trials under common scenarios are better continued and extended even in the face of dropouts, treatment disruptions, missing outcomes, and other exigencies and that adaptations can be made that maintain the trials' validity. We suggest some adaptive methods to do this noting that some changes become under-powered to detect the original effect sizes and expected outcomes. These analyses provide insight to better plan trials that are resilient to unexpected changes to the medical, social, and political milieu.

Glasgow Early Treatment Arm Favirpiravir (GETAFIX) for adults with early stage COVID-19: A structured summary of a study protocol for a randomised controlled trial.

OBJECTIVES: The GETAFIX trial will test the hypothesis that favipiravir is a more effective treatment for COVID-19 infection in patients who have early stage disease, compared to current standard of care. This study will also provide an important opportunity to investigate the safety and tolerability of favipiravir, the pharmacokinetic and pharmacodynamic profile of this drug and mechanisms of resistance in the context of COVID-19 infection, as well as the effect of favipiravir on hospitalisation duration and the post COVID-19 health and psycho-social wellbeing of patients recruited to the study. TRIAL DESIGN: GETAFIX is an open label, parallel group, two arm phase II/III randomised trial with 1:1 treatment allocation ratio. Patients will be randomised to one of two arms and the primary endpoint will assess the superiority of favipiravir plus standard treatment compared to standard treatment alone. PARTICIPANTS: This trial will recruit adult patients with confirmed positive valid COVID-19 test, who are not pregnant or breastfeeding and have no prior major co-morbidities. This is a multi-centre trial, patients will be recruited from in-patients and outpatients from three Glasgow hospitals: Royal Alexandra Hospital; Queen Elizabeth University Hospital; and the Glasgow Royal Infirmary. Patients must meet all of the following criteria: 1. Age 16 or over at time of consent 2. Exhibiting symptoms associated with COVID-19 3. Positive for SARS-CoV-2 on valid COVID-19 test 4. Point 1, 2, 3, or 4 on the WHO COVID-19 ordinal severity scale at time of randomisation. (Asymptomatic with positive valid COVID-19 test, Symptomatic Independent, Symptomatic assistance needed, Hospitalized, with no oxygen therapy) 5. Have >=10% risk of death should they be admitted to hospital as defined by the ISARIC4C risk index: https://isaric4c.net/risk 6. Able to provide written informed consent 7. Negative pregnancy test (women of childbearing potential*) 8. Able to swallow oral medication Patients will be excluded from the trial if they meet any of the following criteria: 1. Renal impairment requiring, or likely to require, dialysis or haemofiltration 2. Pregnant or breastfeeding 3. Of child bearing potential (women), or with female partners of child bearing potential (men) who do not agree to use adequate contraceptive measures for the duration of the study and for 3 months after the completion of study treatment 4. History of hereditary xanthinuria 5. Other patients judged unsuitable by the Principal Investigator or sub-Investigator 6. Known hypersensitivity to favipiravir, its metabolites or any excipients 7. Severe co-morbidities including: patients with severe hepatic impairment, defined as: • greater than Child-Pugh grade A • AST or ALT > 5 x ULN • AST or ALT >3 x ULN and Total Bilirubin > 2xULN 8. More than 96 hours since first positive COVID-19 test sample was taken 9. Unable to discontinue contra-indicated concomitant medications This is a multi-centre trial, patients will be recruited from in-patients and outpatients from three Glasgow hospitals: Royal Alexandra Hospital; Queen Elizabeth University Hospital; and the Glasgow Royal Infirmary. INTERVENTION AND COMPARATOR: Patients randomised to the experimental arm of GETAFIX will receive standard treatment for COVID-19 at the discretion of the treating clinician plus favipiravir. These patients will receive a loading dose of favipiravir on day 1 of 3600mg (1800mg 12 hours apart). On days 2-10, patients in the experimental arm will receive a maintenance dose of favipiravir of 800mg 12 hours apart (total of 18 doses). Patients randomised to the control arm of the GETAFIX trial will receive standard treatment for COVID-19 at the discretion of the treating clinician. MAIN OUTCOMES: The primary outcome being assessed in the GETAFIX trial is the efficacy of favipiravir in addition to standard treatment in patients with COVID-19 in reducing the severity of disease compared to standard treatment alone. Disease severity will be assessed using WHO COVID 10 point ordinal severity scale at day 15 +/- 48 hours. All randomised participants will be followed up until death or 60 days post-randomisation (whichever is sooner). RANDOMISATION: Patients will be randomised 1:1 to the experimental versus control arm using computer generated random sequence allocation. A minimisation algorithm incorporating a random component will be used to allocate patients. The factors used in the minimisation will be: site, age (16-50/51-70/71+), history of hypertension or currently obsess (BMI>30 or obesity clinically evident; yes/no), 7 days duration of symptoms (yes/no/unknown), sex (male/female), WHO COVID-19 ordinal severity score at baseline (1/2or 3/4). BLINDING (MASKING): No blinding will be used in the GETAFIX trial. Both participants and those assessing outcomes will be aware of treatment allocation. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): In total, 302 patients will be randomised to the GETAFIX trial: 151 to the control arm and 151 to the experimental arm. There will be an optional consent form for patients who may want to contribute to more frequent PK and PD sampling. The maximum number of patients who will undergo this testing will be sixteen, eight males and eight females. This option will be offered to all patients who are being treated in hospital at the time of taking informed consent, however only patients in the experimental arm of the trial will be able to undergo this testing. TRIAL STATUS: The current GETAFIX protocol is version 4.0 12th September 2020. GETAFIX opened to recruitment on 26th October 2020 and will recruit patients over a period of approximately six months. TRIAL REGISTRATION: GETAFIX was registered on the European Union Drug Regulating Authorities Clinical Trials (EudraCT) Database on 15th April 2020; Reference number 2020-001904-41 ( https://www.clinicaltrialsregister.eu/ctr-search/trial/2020-001904-41/GB ). GETAFIX was registered on ISRCTN on 7th September 2020; Reference number ISRCTN31062548 ( https://www.isrctn.com/ISRCTN31062548 ). FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol. The study protocol has been reported in accordance with the Standard Protocol Items: Recommendations for Clinical Interventional Trials (SPIRIT) guidelines (see Additional file 2).

Cyclic hydrostatic pressure and cotton particles stimulate synthesis by human lung macrophages of cytokines in vitro.

BACKGROUND: Inhalation of particulates is a leading cause of the development of lung diseases and current understanding of the complex relationship between lung metabolism and airborne particulates is incomplete. It is well established that mechanical load is important in the development of the lung and in lung cell differentiation. The interaction between particle exposure and physical forces on alveolar macrophages is a physiologically relevant issue, but as yet understudied. This study examines the effect of cyclic hydrostatic pressure and cotton particles on synthesis of cytokines by human alveolar macrophages. METHODS: Alveolar macrophages were obtained from patients with lung disease, either from lavage samples or from lung tissue resection. The commonly used cell line THP-1 was included in the experiments. Cell cultures were exposed to cotton particles and/cyclic hydrostatic pressure (3 or 5 psi); control cultures were exposed to medium only. TNFalpha, IL-1beta and IL-6 were assayed in the culture media using specific ELISAs. Cells were characterized using morphology and markers specific for macrophages (Jenner/Giemsa staining, CD14 and CD68). RESULTS: Exposure to cotton particles stimulated cytokine synthesis by macrophages from all three sources; exposure to cyclic hydrostatic pressure alone did not stimulate cytokine synthesis significantly. However, the combination of both particles and cyclic hydrostatic pressure increased the simulation of cytokine synthesis still further. Cell characterization demonstrated that the large majority of cells had a macrophage morphology and were positive for CD14 and CD68. CONCLUSION: These data suggest an interaction between cyclic hydrostatic pressure and particulate exposure, which increases alveolar macrophage cytokine production. This interaction was only observed at the higher cyclic hydrostatic pressure. However, in patient samples, there was considerable variation in the amount by which secretion of an individual cytokine increased and there was also variation in the mechanosensitivity of cells from the three different sources. Cyclic hydrostatic pressure, therefore, may be an important modulator of the response of alveolar macrophages to cotton particles, but the source of the cells may be a confounding factor which demands further investigation.