ERS International Congress 2023: highlights from the Epidemiology and Environment Assembly.

In this article, early career members of the Epidemiology and Environment Assembly of the European Respiratory Society (ERS) summarise a selection of four poster and oral sessions from the ERS 2023 Congress. The topics covered the following areas: micro- and macro-environments and respiratory health, occupational upper and lower airway diseases, selected tobacco and nicotine research, and multimorbidity in people with lung diseases. The topics and studies covered in this review illustrate the broad range of the multifaceted research taking place within Assembly 6, from the identification of indoor and outdoor environmental risk factors for the development and worsening of respiratory diseases to the concerningly increasing use of nicotine products and their health consequences beyond respiratory health and comorbidity in respiratory diseases.

Lung Disease and Social Justice: Chronic Obstructive Pulmonary Disease as a Manifestation of Structural Violence.

Lung health, the development of lung disease, and how well a person with lung disease is able to live all depend on a wide range of societal factors. These systemic factors that adversely affect people and cause injustice can be thought of as "structural violence." To make the causal processes relating to chronic obstructive pulmonary disease (COPD) more apparent, and the responsibility to interrupt or alleviate them clearer, we have developed a taxonomy to describe this. It contains five domains: 1) avoidable lung harms (processes impacting lung development, processes that disadvantage lung health in particular groups across the life course), 2) diagnostic delay (healthcare factors; norms and attitudes that mean COPD is not diagnosed in a timely way, denying people with COPD effective treatment), 3) inadequate COPD care (ways in which the provision of care for people with COPD falls short of what is needed to ensure they are able to enjoy the best possible health, considered as healthcare resource allocation and norms and attitudes influencing clinical practice), 4) low status of COPD (ways COPD as a condition and people with COPD are held in less regard and considered less of a priority than other comparable health problems), and 5) lack of support (factors that make living with COPD more difficult than it should be, i.e., socioenvironmental factors and factors that promote social isolation). This model has relevance for policymakers, healthcare professionals, and the public as an educational resource to change clinical practices and priorities and stimulate advocacy and activism with the goal of the elimination of COPD.

Immediate smoking cessation support during lung cancer screening: long-term outcomes from two randomised controlled trials.

BACKGROUND: Immediate smoking cessation interventions delivered alongside targeted lung health checks (TLHCs) to screen for lung cancer increase self-reported abstinence at 3 months. The impact on longer term, objectively confirmed quit rates remains to be established. METHODS: We followed up participants from two clinical trials in people aged 55-75 years who smoked and took part in a TLHC. These randomised participants in the TLHC by day of attendance to either usual care (UC) (signposting to smoking cessation services) or an offer of immediate smoking cessation support including pharmacotherapy. In the QuLIT1 trial, this was delivered face to face and in QuLIT2, it was delivered remotely. Follow-up was conducted 12 months after the TLHC by telephone interview with subsequent biochemical verification of smoking cessation using exhaled CO. RESULTS: 430 people were enrolled initially (115 in QuLIT1 and 315 in QuLIT2), with 4 deaths before 12 months leaving 426 (62.1±5.27 years old and 48% women) participants for analysis. At 12 months, those randomised to attend on smoking cessation support intervention days had higher quit rates compared with UC adjusted for age, gender, deprivation, and which trial they had been in; self-reported 7-day point prevalence (20.0% vs 12.8%; adjusted OR (AOR)=1.78; 95% CI 1.04 to 2.89) and CO-verified quits (12.1% vs 4.7%; AOR=2.97; 95% CI 1.38 to 6.90). Those in the intervention arm were also more likely to report having made a quit attempt (30.2% vs UC 18.5%; AOR 1.90; 95% CI 1.15 to 3.15). CONCLUSION: Providing immediate smoking cessation support alongside TLHC increases long term, biochemically confirmed smoking abstinence. TRIAL REGISTRATION NUMBER: ISRCTN12455871.

Investigating the prognostic value of digital mobility outcomes in patients with chronic obstructive pulmonary disease: a systematic literature review and meta-analysis.

BACKGROUND: Reduced mobility is a central feature of COPD. Assessment of mobility outcomes that can be measured digitally (digital mobility outcomes (DMOs)) in daily life such as gait speed and steps per day is increasingly possible using devices such as pedometers and accelerometers, but the predictive value of these measures remains unclear in relation to key outcomes such as hospital admission and survival. METHODS: We conducted a systematic review, nested within a larger scoping review by the MOBILISE-D consortium, addressing DMOs in a range of chronic conditions. Qualitative and quantitative analysis considering steps per day and gait speed and their association with clinical outcomes in COPD patients was performed. RESULTS: 21 studies (6076 participants) were included. Nine studies evaluated steps per day and 11 evaluated a measure reflecting gait speed in daily life. Negative associations were demonstrated between mortality risk and steps per day (per 1000 steps) (hazard ratio (HR) 0.81, 95% CI 0.75-0.88, p<0.001), gait speed (<0.80 m·s-1) (HR 3.55, 95% CI 1.72-7.36, p<0.001) and gait speed (per 1.0 m·s-1) (HR 7.55, 95% CI 1.11-51.3, p=0.04). Fewer steps per day (per 1000) and slow gait speed (<0.80 m·s-1) were also associated with increased healthcare utilisation (HR 0.80, 95% CI 0.72-0.88, p<0.001; OR 3.36, 95% CI 1.42-7.94, p=0.01, respectively). Available evidence was of low-moderate quality with few studies eligible for meta-analysis. CONCLUSION: Daily step count and gait speed are negatively associated with mortality risk and other important outcomes in people with COPD and therefore may have value as prognostic indicators in clinical trials, but the quantity and quality of evidence is limited. Larger studies with consistent methodologies are called for.

Development and implementation of the lung volume reduction pulmonary rehabilitation tool to identify eligibility for lung volume reduction in people with chronic obstructive pulmonary disease during pulmonary rehabilitation.

BACKGROUND: Completion of pulmonary rehabilitation is recognised in chronic obstructive pulmonary disease (COPD) guidelines as a key opportunity to consider systematically whether a respiratory review to assess potential suitability for a lung volume reduction (LVR) procedure might be appropriate. We describe the development of a simple decision-support tool (the LVR-PR tool) to aid clinicians working in pulmonary rehabilitation, to operationalise this process. METHODS: We took an iterative mixed methods approach, which was partnership-based and involved an initial consensus survey, focus groups and an observational study cohort at multiple pulmonary rehabilitation centres. RESULTS: Diagnosis (97%), exercise capacity (84%), breathlessness (78%) and co-morbidities (76%) were acknowledged to be essential items for assessing basic LVR eligibility. Collating prior investigations and assessing patient understanding were considered useful but not essential. Clinician concerns included; streamlining the tool; access to clinical information and investigations; and care needed around introducing LVR therapies to patients in a PR setting. Access to clearer information about LVR procedures, the clinician's role in considering eligibility and how educational resources should be delivered were identified as important themes from patient group discussions. The LVR-PR tool was considered to be feasible and valid for implementation in a variety of PR services across the UK subject to the provision of appropriate health professional training. Clinicians working in specialist LVR centres across the UK who were not otherwise involved in the development process confirmed the tool's validity using the content validity index (CVI). INTERPRETATION: The LVR-PR tool appears to be an acceptable tool that can be feasibly implemented in PR services subject to good quality educational resources for both patients and healthcare professionals.

Strategies to deliver smoking cessation interventions during targeted lung health screening - a systematic review and meta-analysis.

INTRODUCTION: Lung cancer screening presents an important teachable moment to promote smoking cessation, but the most effective strategy to deliver support in this context remains to be established. METHODS: We undertook a systematic review and meta-analysis of smoking cessation interventions delivered during lung health screening, published prior to 20/07/2022 MEDLINE, PsychINFO, CENTRAL, EMBASE, CINAHL and Scopus databases. Two reviewers screened titles, and abstracts, four reviewed each full text using prespecified criteria, extracted relevant data, assessed risk of bias and confidence in findings using the GRADE criteria. The review was registered prospectively on PROSPERO (CRD42021242431). RESULTS: 10 randomised controlled trials and three observational studies with a control group were identified. Meta-analysis of nine RCTs demonstrated that smoking cessation interventions delivered during lung screening programmes increased quit rates compared to usual care (odds ratios: 2.01, 95%: 1.49-2.72 p < 0.001). Six RCTs using intensive (≥3 behavioural counselling sessions) interventions demonstrated greater quit rates compared to usual care (OR: 2.11, 95% CI 1.53-2.90, p < 0.001). A meta-analysis of two RCTs found intensive interventions were more effective than non-intensive (OR: 2.07, 95%CI 1.26-3.40 p = 0.004), Meta-analysis of two RCTs of non-intensive interventions (≤2 behavioural counselling sessions or limited to online information audio take home materials such as pamphlets) did not show a higher quit rate than usual care (OR: 0.90, 95% CI 0.39-2.08 p = 0.80). DISCUSSION: Moderate quality evidence supports smoking cessation interventions delivered within a lung screening setting compared to usual care, with high-quality evidence that more intensive interventions are likely to be most effective.

Use of tobacco and e-cigarettes among youth in Great Britain in 2022: Analysis of a cross-sectional survey.

INTRODUCTION: Although e-cigarettes can be an effective form of nicotine substitution for adults attempting to quit smoking, their use among children and young people is a concern. Accurate data about this are needed to inform debates over policy and regulation in the UK and elsewhere. METHODS: Using data from an online survey of 2613 youth aged 11-18 years, conducted by the market research company YouGov in March 2022, we present prevalence estimates of e-cigarette and tobacco use. We use logistic regression models to assess differences in e-cigarette use, tobacco use and use of disposable e-cigarettes across a range of covariates including age, sex, tobacco smoking status, social class, and country. RESULTS: Among the 18.0% of those surveyed who reported ever having smoked a cigarette, 83.9% were not regular (at least once per week) smokers and 16.1% were (15.1% and 2.9% of the total sample, respectively). Among the 19.2% of those surveyed who had ever used an e-cigarette, 79.2% were not regular users, while 20.8% were (15.2% and 4.0% of the total sample, respectively). Regular e-cigarette use was more common than regular tobacco smoking (4.0% vs 2.9%). E-cigarette use was more common among those who also smoked tobacco, with 9.0% of never e-cigarette users ever smoking tobacco, compared with 89.4% of regular e-cigarette users. Both smoking and e-cigarette use were associated with increasing age and use by others within the home, but not with social class. Use of disposable e-cigarettes was reported by 53.8% of those who have ever used an e-cigarette, and more common among females than males. CONCLUSIONS: Regular e-cigarette use is now more common than smoking in children and youth, though the majority of this is among those who have also smoked tobacco. Measures to reduce the appeal of both e-cigarettes and tobacco to children and young people are warranted.

Immediate, Remote Smoking Cessation Intervention in Participants Undergoing a Targeted Lung Health Check: Quit Smoking Lung Health Intervention Trial, a Randomized Controlled Trial.

BACKGROUND: Lung cancer screening programs provide an opportunity to support people who smoke to quit, but the most appropriate model for delivery remains to be determined. Immediate face-to-face smoking cessation support for people undergoing screening can increase quit rates, but it is not known whether remote delivery of immediate smoking cessation counselling and pharmacotherapy in this context also is effective. RESEARCH QUESTION: Does an immediate telephone smoking cessation intervention increase quit rates compared with usual care among a population enrolled in a targeted lung health check (TLHC)? STUDY DESIGN AND METHODS: In a single-masked randomized controlled trial, people 55 to 75 years of age who smoke and attended a TLHC were allocated by day of attendance to receive either immediate telephone smoking cessation intervention (TSI) support (starting immediately and lasting for 6 weeks) with appropriate pharmacotherapy or usual care (UC; very brief advice to quit and signposting to smoking cessation services). The primary outcome was self-reported 7-day point prevalence smoking abstinence at 3 months. Differences between groups were assessed using logistic regression. RESULTS: Three hundred fifteen people taking part in the screening program who reported current smoking with a mean ± SD age of 63 ± 5.4 years, 48% of whom were women, were randomized to TSI (n = 152) or UC (n = 163). The two groups were well matched at baseline. Self-reported quit rates were higher in the intervention arm, 21.1% vs 8.9% (OR, 2.83; 95% CI, 1.44-5.61; P = .002). Controlling for participant demographics, neither baseline smoking characteristics nor the discovery of abnormalities on low-dose CT imaging modified the effect of the intervention. INTERPRETATION: Immediate provision of an intensive telephone-based smoking cessation intervention including pharmacotherapy, delivered within a targeted lung screening context, is associated with increased smoking abstinence at 3 months. TRIAL REGISTRY: ISRCTN registry; No.: ISRCTN12455871; URL: www.IRSCN.com.

Reporting of data on participant ethnicity and socioeconomic status in high-impact medical journals: a targeted literature review.

OBJECTIVES: To assess the frequency of reporting of ethnicity (or 'race') and socioeconomic status (SES) indicators in high-impact journals. DESIGN: Targeted literature review. DATA SOURCES: The 10 highest ranked general medical journals using Google scholar h5 index. ELIGIBILITY CRITERIA: Inclusion criteria were, human research, reporting participant level data. Exclusion criteria were non-research article, animal/other non-human participant/subject or no participant characteristics reported. DATA EXTRACTION AND SYNTHESIS: Working backwards from 19 April 2021 in each journal, two independent reviewers selected the 10 most recent articles meeting inclusion/exclusion criteria, to create a sample of 100 articles. Data on the frequency of reporting of ethnicity (or 'race') and SES indicators were extracted and presented using descriptive statistics. RESULTS: Of 100 research articles included, 35 reported ethnicity and 13 SES. By contrast, 99 reported age, and 97 reported sex or gender. Among the articles not reporting ethnicity, only 3 (5%) highlighted this as a limitation, and only 6 (7%) where SES data were missing. Median number of articles reporting ethnicity per journal was 2.5/10 (range 0 to 9). Only two journals explicitly requested reporting of ethnicity (or race), and one requested SES. CONCLUSIONS: The majority of research published in high-impact medical journals does not include data on the ethnicity and SES of participants, and this omission is rarely acknowledged as a limitation. This situation persists despite the well-established importance of this issue and International Committee of Medical Journal Editors recommendations to include relevant demographic variables to ensure representative samples. Standardised explicit minimum standards are required.

Smoking and socioeconomic factors linked to acute exacerbations of COPD: analysis from an Asthma + Lung UK survey.

BACKGROUND: Understanding the factors driving acute exacerbations of chronic obstructive pulmonary disease (COPD) is key to reducing their impact on human health and well-being. METHODS: 5997 people with COPD, mean 66 years, 64% female, completed an online survey between December 2020 and May 2021 about living with COPD, developed by the charity Asthma + Lung UK. RESULTS: The 3731 (62.2%) survey participants reporting frequent (≥2/year) exacerbations were more likely to smoke (adjusted OR (AOR) 1.70, 95% CI 1.470 to 1.98), have lower annual household income (≤£20 000 (AOR 1.72, 95% CI 1.36 to 2.17), live in a cold and damp home (AOR 1.78, 95% CI 1.50 to 2.11) and report previous occupational exposure to dust, fumes and chemicals. Smokers were more likely to report attending hospital to manage their most recent acute exacerbation of COPD compared with ex-smokers (AOR 1.25, 95% CI 0.99 to 1.59). DISCUSSION: Strategies to improve COPD outcomes must address issues of deprivation and social justice.

Extracerebellar role for Cerebellin1: modulation of dendritic spine density and synapses in striatal medium spiny neurons.

Cerebellin1 (Cbln1) is a secreted glycoprotein that was originally isolated from the cerebellum and subsequently found to regulate synaptic development and stability. Cbln1 has a heterogeneous distribution in brain, but the only site in which it has been shown to have central effects is the cerebellar cortex, where loss of Cbln1 causes a reduction in granule cell-Purkinje cell synapses. Neurons of the thalamic parafascicular nucleus (PF), which provide glutamatergic projections to the striatum, also express high levels of Cbln1. We first examined Cbln1 in thalamostriatal neurons and then determined if cbln1 knockout mice exhibit structural deficits in striatal neurons. Virtually all PF neurons express Cbln1-immunoreactivity (-ir). In contrast, only rare Cbln1-ir neurons are present in the central medial complex, the other thalamic region that projects heavily to the dorsal striatum. In the striatum Cbln1-ir processes are apposed to medium spiny neuron (MSN) dendrites; ultrastructural studies revealed that Cbln1-ir axon terminals form axodendritic synapses with MSNs. Tract-tracing studies found that all PF cells retrogradely labeled from the striatum express Cbln1-ir. We then examined the dendritic structure of Golgi-impregnated MSNs in adult cbln1 knockout mice. MSN dendritic spine density was markedly increased in cbln1(-/-) mice relative to wildtype littermates, but total dendritic length was unchanged. Ultrastructural examination revealed an increase in the density of MSN axospinous synapses in cbln1(-/-) mice, with no change in postsynaptic density length. Thus, Cbln1 determines the dendritic structure of striatal MSNs, with effects distinct from those seen in the cerebellum.

High prevalence of hepatitis C virus but not HIV co-infection among patients with tuberculosis in Georgia.

SETTING: Tuberculosis (TB) and hepatitis C virus (HCV) infection have emerged as major public health problems in former Soviet republics. OBJECTIVE: To determine the prevalence and risk factors for the human immunodeficiency virus (HIV) and HCV co-infection among patients with TB in Georgia, a cross-sectional study was carried out at hospitals in four Georgian cities. RESULTS: Of 272 hospitalized patients with TB, 61 (22%) were found to be HCV-seropositive and three (1%) were HIV-seropositive. The median age of those with TB was 35 years (range 18-74 years); 74% were male. In multivariate analysis, risk factors for HCV co-infection included previous incarceration (OR 4.6, 95%CI 1.9-10.8), history of receiving a tattoo (OR 2.6, 95%CI 1.2-5.7), previous diagnosis of a sexually transmitted infection (OR 7.2, 95%CI 1.4-37.8), and age 26-45 years (OR 2.1, 95%CI 1.0-4.6). CONCLUSION: HCV co-infection was common among hospitalized patients with TB in Georgia. Incarceration and receiving a tattoo, a common practice among inmates in Georgian and former Soviet correctional facilities, were important independent risk factors associated with HCV infection among those with TB. Further studies are needed to assess the impact of the high prevalence of HCV co-infection on treatment outcomes, including tolerability and risk of anti-tuberculosis drug induced hepatotoxicity.

Cholinergic and behavioral neurotoxicity of carbaryl and cadmium to larval rainbow trout (Oncorhynchus mykiss).

Pesticides and heavy metals are common environmental contaminants that can cause neurotoxicity to aquatic organisms, impairing reproduction and survival. Neurotoxic effects of cadmium and carbaryl exposures were estimated in larval rainbow trout (RBT; Oncorhynchus mykiss) using changes in physiological endpoints and correlations with behavioral responses. Following exposures, RBT were videotaped to assess swimming speed. Brain tissue was used to measure cholinesterase (ChE) activity, muscarinic cholinergic receptor (MChR) number, and MChR affinity. ChE activity decreased with increasing concentrations of carbaryl but not of cadmium. MChR were not affected by exposure to either carbaryl or cadmium. Swimming speed correlated with ChE activity in carbaryl-exposed RBT, but no correlation occurred in cadmium-exposed fish. Thus, carbaryl exposure resulted in neurotoxicity reflected by changes in physiological and behavioral parameters measured, while cadmium exposure did not. Correlations between behavior and physiology provide a useful assessment of neurotoxicity.

Influence of MHC background on the antibody response to detergent enzymes in the mouse intranasal test.

The mouse intranasal test (MINT) was developed to assess the immunogenic potential of detergent enzymes. The BDF1 mouse (H-2(b/d)), a cross of C57Bl/6 (H-2(b)) x DBA/2 (H-2(d)) has been used for most of the development work. Preliminary data in the CB6F1(H-2(d/b)), a cross of Balb/c (H-2(d)) x C57Bl/6 showed that this strain was similar to the BDF1 in its response to enzymes. These data also showed that the parental strains responded differently to the enzymes. To understand better the influence the major histocompatibility complex (MHC) background has on immune responses to enzymes, 3 different enzymes were tested in 4 inbred strains (C57Bl/6, DBA/2, Balb/c, and C57Bl/10), 2 hybrid strains (BDF1 and CB6F1), and 2 congenic strains (Balb.B10 and B10.D2). BDF1 mice rank enzymes the same as the guinea pig, which in turn correlates with sensitization in occupationally exposed humans. The ranking is based upon the dose of enzyme needed to give one-half maximal IgG1 antibody response (ED(50)) where Termamyl is more potent than Alcalase, which is equipotent to Savinase. The H-2(d) strains ranked the enzymes the same as the BDF1 but generated ED(50)s for the proteases that were one order of magnitude greater than the BDF1 ED(50)s. The response to Termamyl was the same in the two F1 strains and the H-2(d) strains. The H-2(b) strains did not rank the enzymes the same as BDF1 but the ED(50)s for the proteases were similar to the ED(50)s in the F1 strains. The response to Termamyl in the H-2(b) strains was lower than the response in the F1 and H-2(d) strains. Initial data show that the inbred strains will make enzyme-specific IgE antibody to high doses of enzyme with DBA/2 > Balb/c > C57Bl/6 in terms of the robustness of the response. The IgG1 responses in the congenic strains were similar to the responses in the H-2 matched strains. In addition, the antibody response to enzymes was consistent regardless of the source of BDF1 mice. The responses to these enzymes are clearly MHC linked with a role for Class II I-E molecules indicated. The current data strongly support the use of the F1 hybrid as an appropriate strain for evaluating allergic responses to enzymes.

An approach for assessment of water quality using semipermeable membrane devices (SPMDs) and bioindicator tests.

As an integral part of our continued development of water quality assessment approaches, we combined integrative sampling, instrumental analysis of widely occurring anthropogenic contaminants, and the application of a suite of bioindicator tests as a specific part of a broader survey of ecological conditions, species diversity, and habitat quality in the Santa Cruz River in Arizona, USA. Lipid-containing semipermeable membrane devices (SPMDs) were employed to sequester waterborne hydrophobic chemicals. Instrumental analysis and a suite of bioindicator tests were used to determine the presence and potential toxicological relevance of mixtures of bioavailable chemicals in two major water sources of the Santa Cruz River. The SPMDs were deployed at two sites; the effluent weir of the International Wastewater Treatment Plant (IWWTP) and the Nogales Wash. Both of these systems empty into the Santa Cruz River and the IWWTP effluent is a potential source of water for a constructed wetland complex. Analysis of the SPMD sample extracts revealed the presence of organochlorine pesticides (OCs), polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs). The bioindicator tests demonstrated increased liver enzyme activity, perturbation of neurotransmitter systems and potential endocrine disrupting effects (vitellogenin induction) in fish exposed to the extracts. With increasing global demands on limited water resources, the approach described herein provides an assessment paradigm applicable to determining the quality of water in a broad range of aquatic systems.

Partnerships in healthcare: a Commonwealth perspective.

This article briefly outlines the nature and characteristics of partnership, and points to the need to build partnerships through deliberate efforts, since they do not occur by simply bringing people and/or resources together. It identifies some of the reasons why partnerships in health are invaluable in meeting the priority health needs of populations, and the importance which the Commonwealth places on partnerships given the unique characteristics which are common to its member countries. The article then uses practical examples to illustrate the value of partnerships in health at the national, regional and international level. For the benefit of front-line healthcare providers, some suggestions are given of how partnerships could be used to enhance the services which they give to the communities they serve.

Tumour necrosis factor-alpha activates a calcium sensitization pathway in guinea-pig bronchial smooth muscle.

1. The effects of tumour necrosis factor-alpha (TNF) on guinea-pig bronchial smooth muscle contractility were investigated. 2. The Ca2+-activated contractile response of permeabilized bronchial smooth muscle strips was significantly increased after incubation with 1 microgram ml-1 TNF for 45 min. This TNF-induced effect was not due to a further increase in intracellular Ca2+. 3. The TNF-induced Ca2+ sensitization was, at least partly, the result of an increase in myosin light chain20 phosphorylation. 4. The intracellular signalling pathway involved in this effect of TNF was further investigated. Sphingomyelinase, a potential mediator of TNF, had no effect on Ca2+ sensitivity of permeabilized bronchial smooth muscle. Also, p42/p44 mitogen-activated protein kinase (p42/p44mapk), activated by TNF in some cell types, did not show an increased activation in bronchial smooth muscle after TNF treatment. 5. In conclusion, TNF may activate a novel signalling pathway in guinea-pig bronchial smooth muscle leading to an increase in myosin light chain20 phosphorylation and a subsequent increase in Ca2+ sensitivity of the myofilaments. This pathway does not appear to involve sphingomyelinase-liberated ceramides or activation of p42/p44mapk. Given the importance of TNF in asthma, this TNF-induced Ca2+ sensitization of the myofilaments may represent a mechanism responsible for airway hyper-responsiveness.

Effectiveness of apical clearing: histological and radiographical evaluation.

Preparation of the apical one-third in curved canals is difficult both in debridement and maintaining canal shape. A technique of final apical preparation, "apical clearing," attempted to debride and increase the apical size without transportation. Apical clearing is defined as: following cleaning and shaping, sequentially rotating files two to four sizes larger than the initial (master) apical file at working length, then rotating the largest apical file again after a final irrigation and drying. This study evaluated histologically and radiographically the quality of apical preparation with or without apical clearing. Examined were (a) extent of transportation and (b) debris accumulation in the apical third. Fifty-four extracted teeth with vital pulps and curved canals were divided into two groups. After step-back preparation, 29 had apical clearing and 25 did not. Pre- and postpreparation double-exposed radiographs evaluated canal deviation. The apical one-third of the canals was examined histologically and ranked, based on remaining tissue, predentin, dentin shavings, other debris, and canal walls planed. Radiographically, the apically cleared group showed slight deviation of the canal during preparation. Histologically, canals in the apically cleared group had significantly less remaining tissue, predentin and debris, as well as more canal walls planed. This experiment showed that apically the apical clearing technique resulted in better debridement, with minimal increase in apical transportation.

Learning through experience.

PIP: After the first AIDS patients were diagnosed in 1983 in Trinidad and Tobago, every nurse attended a large group lecture on HIV/AIDS which lasted 1 or 2 days. Even though the information acquired helped them greatly in infection control, the lectures did not prepare them adequately for caring for AIDS patients. The nurses did not want to treat AIDS patients and would not make home visits. They feared infection with HIV and stigmatization through their contact with AIDS patients. They often believed God was punishing AIDS patients. They were intolerant of homosexual men and were more willing to care for HIV/AIDS patients who were children or infected by a blood transfusion. In 1990, these attitudes and beliefs prompted a modification of the design of the training program. The program now involves all participants and uses role playing to simulate reality. Each training course has only 10-15 people and is informal and relaxed. It is held 1 day a week for 8 weeks. The subject matter depends on participants' needs identified through a questionnaire they complete before the course. Group discussions often include HIV positive people, family members, and experienced nurses. The nurses leave the course with a better understanding of the feelings and needs of people with AIDS, human sexuality, and the diversity of sexual behaviors. They are also better able to separate illness from sexual practice, recognize the value of each patient, communicate with and encourage families to accept the patient, support the patient, spread the word about prevention of HIV and sexually transmitted diseases, and understand issues of HIV-positive homosexual and bisexual men. The primary health care system in Trinidad and Tobago serves HIV/AIDS patients. The nurses visit them in their homes and make sure they receive the care they need at hospitals and outpatient clinics.^ieng

Production of organic compounds in plasmas: a comparison among electric sparks, laser-induced plasmas, and UV light.

The chemistry in planetary atmospheres that is induced by processes associated with high-temperature plasmas is of broad interest because such processes may explain many of the chemical species observed. There are at least two important phenomena that are known to generate plasmas (and shocks) in planetary atmospheres: lightning and meteor impacts. For both phenomena, rapid heating of atmospheric gases leads to formation of a high-temperature plasma which emits radiation and produces shock waves that propagate through the surrounding atmosphere. These processes initiate chemical reactions that can transform simple gases into more complex compounds. In order to study the production of organic compounds in plasmas (shocks), various mixtures of N2, CH4, and H2, modeling the atmosphere of Titan, were exposed to discrete sparks, laser-induced plasmas (LIP), an ultraviolet radiation. The yields of HCN and several simple hydrocarbons were measured by gas chromatography and compared to those calculated from a simple quenched thermodynamic equilibrium model. The agreement between experiment and theory was fair for HCN and C2H2. However, the agreement for C2H6 and the other hydrocarbons was poor, indicating that a more comprehensive theory is needed. Our experiments suggest that photolysis by ultraviolet light from the plasma is an important process in the synthesis. This was confirmed by the photolysis of gas samples exposed to the light but not to the shock waves emitted by the sparks. Hence, the results of these experiments demonstrate that the thermodynamic equilibrium theory does not adequately model lightning and meteor impacts and that photolysis must be included. Finally, the similarity in yields between the spark and the LIP experiments suggest that LIP provide valid and clean simulations of lightning and meteor impacts and that photolysis must be included. Finally, the similarity in yields between the spark and the LIP experiments suggests that LIP provide valid and clean simulations of lightning in planetary atmospheres.