Incremental step test in patients with pulmonary hypertension.

Cardiopulmonary exercise testing (CPET) on a treadmill or cycle ergometer provides an integrated assessment of the cardiorespiratory system during exertion and is widely used in clinical practice. An incremental step test (IST) can be an alternative for eliciting maximal exercise responses. Therefore, 20 patients with pre-capillary PH (65% female, 41 ±â€¯15 yrs) randomly performed a symptom-limited CPET on a cycle ergometer and IST. Metabolic, cardiovascular, ventilatory and gas exchange variables were recorded during both tests. There was a greater desaturation and higher V̇O2PEAK in IST compared to CPET. The V̇O2GET, HR PEAK (% pred), ΔV̇E/ΔV̇CO2 and ΔHR/ΔV̇O2 were similar in both IST and CPET. By linear regression analyses, the work performed on IST [W = (mass × 9,8 m/s2 x vertical distance)] was a predictor of peak V̇O2 independent of the gender and age (r2 = 077, p = 0001). In conclusion, IST elicited higher peak cardiopulmonary responses and has a good agreement with known severity markers in patients with pre-capillary PH.

Increased rate of osteoporosis, low lean mass, and fragility fractures in COPD patients: association with disease severity.

A very high rate of osteoporosis, fractures, and low lean mass was observed in patients with chronic obstructive pulmonary disease (COPD). Disease severity was associated with bone and muscle adverse outcomes, while age ≥ 63.5 years old, low lean mass, higher iPTH, and a T-score below - 2.5 were all associated with higher risk of fracture. INTRODUCTION: Osteoporosis is frequently neglected in patients with COPD. We aimed at evaluating the rate of osteoporosis, fractures, and low lean mass in patients with COPD. METHODS: Ninety-nine patients with COPD (53 women, 64.5 ± 9.6 years old, and 46 men, 65.9 ± 8.0 years old) underwent bone densitometry (DXA) with body composition analyses. Healthy individuals (N = 57) not exposed to tobacco matched by sex, age, and body mass index (BMI) were used as controls. Spirometry, routine laboratory workout, and conventional thoracolumbar radiography surveying for vertebral deformities were performed in all patients. RESULTS: Osteoporosis was found in 40.4% of the COPD patients against only 13.0% of the healthy controls (p = 0.001). Vertebral fractures were seen in 24.4% of the men and 22.0% of the women with COPD. Disease severity (GOLD 3 and 4) was significantly associated with higher risk of vitamin D deficiency (p = 0.032), lower BMD (both men and women at all sites), higher frequency of osteoporosis (in women at all sites), lower skeletal mass index, and higher rate of low lean mass (in both men and women) than healthy controls and COPD patients with milder disease (GOLD 1 and 2). Age was a main predictor of vertebral fractures (OR = 1.164 (1.078-9.297); p < 0.001), while high plasma iPTH (OR = 1.045 (1.005-1.088); p = 0.029) and low ALM (OR = 0.99965 (0.99933-0.99997); p = 0.031) were predictors of non-vertebral fractures. CONCLUSION: Highly prevalent in COPD, osteoporosis and low lean mass were associated with FEV1% < 50%. Age, low lean mass, high iPTH, and low bone mass were all significantly associated with fractures in COPD patients.

Clock genes expression and locomotor activity are altered along the light-dark cycle in transgenic zebrafish overexpressing growth hormone.

In the present work it was demonstrated that transgenic Danio rerio overexpressing growth hormone (GH-transgenic) present either altered gene expression at a determined time point, or different expression pattern along the LD cycle, when compared with non-transgenic (NT) animals, in the positive and negative loops of the circadian system. Gene expression of clock paralogs was reduced in GH fish at the beginning of the dark phase, leading to diminished expression amplitude along the LD cycle. Furthermore, although no differences were observed between NT and GH animals for bmal1a and cry2b expression at each time point, only GH fish presented amplitude along the LD cycle. Also, the locomotor activity behavior was evaluated for both groups. GH-transgenic animals presented higher locomotor activity along the whole LD cycle when compared with NT animals. These data suggest that alterations in the gene expression patterns along the LD cycle of the positive and negative loops of the circadian system, could lead to altered locomotor activity behavior in GH-transgenic fish, and GH overexpression could be responsible for these alterations, either affecting the pathways involved in the expression of genes from the circadian system or altering the metabolism.

Clinical usefulness of end-tidal CO2 profiles during incremental exercise in patients with chronic thromboembolic pulmonary hypertension.

INTRODUCTION: Great ventilation to carbon dioxide output (ΔV˙E/ΔV˙CO2) and reduced end-tidal partial pressures for CO2 (PetCO2) during incremental exercise are hallmarks of chronic thromboembolic pulmonary hypertension (CTEPH) and idiopathic pulmonary arterial hypertension (IPAH). However, CTEPH is more likely to involve proximal arteries, which may lead to poorer right ventricle-pulmonary vascular coupling and worse gas exchange abnormalities. Therefore, abnormal PetCO2 profiles during exercise may be more prominent in patients with CTEPH and could be helpful to indicate disease severity. METHODS: Seventy patients with CTEPH and 34 with IPAH underwent right heart catheterization and cardiopulmonary exercise testing. According to PetCO2 pattern during exercise, patients were classified as having an increase or stabilization in PetCO2 up to the gas exchange threshold (GET), an abrupt decrease in the rest-exercise transition or a progressive and slow decrease throughout exercise. A subgroup of patients with CTEPH underwent a constant work rate exercise test to obtain arterial blood samples during steady-state exercise. RESULTS: Multivariate logistic regression analyses showed that progressive decreases in PetCO2 and SpO2 were better discriminative parameters than ΔV˙E/ΔV˙CO2 to distinguish CTEPH from IPAH. This pattern of PetCO2 was associated with worse functional impairment and greater reduction in PaCO2 during exercise. CONCLUSION: Compared to patients with IPAH, patients with CTEPH present more impaired gas exchange during exercise, and PetCO2 abnormalities may be used to identify more clinically and hemodynamically severe cases.

Effect of L-carnitine on exercise performance in patients with mitochondrial myopathy

Exercise intolerance due to impaired oxidative metabolism is a prominent symptom in patients with mitochondrial myopathy (MM), but it is still uncertain whether L-carnitine supplementation is beneficial for patients with MM. The aim of our study was to investigate the effects of L-carnitine on exercise performance in MM. Twelve MM subjects (mean age±SD=35.4±10.8 years) with chronic progressive external ophthalmoplegia (CPEO) were first compared to 10 healthy controls (mean age±SD=29±7.8 years) before they were randomly assigned to receive L-carnitine supplementation (3 g/daily) or placebo in a double-blind crossover design. Clinical status, body composition, respiratory function tests, peripheral muscle strength (isokinetic and isometric torque) and cardiopulmonary exercise tests (incremental to peak exercise and at 70% of maximal), constant work rate (CWR) exercise test, to the limit of tolerance [Tlim]) were assessed after 2 months of L-carnitine/placebo administration. Patients with MM presented with lower mean height, total body weight, fat-free mass, and peripheral muscle strength compared to controls in the pre-test evaluation. After L-carnitine supplementation, the patients with MM significantly improved their Tlim (14±1.9 vs 11±1.4 min) and oxygen consumption ( V ˙ O 2 ) at CWR exercise, both at isotime (1151±115 vs 1049±104 mL/min) and at Tlim (1223±114 vs 1060±108 mL/min). These results indicate that L-carnitine supplementation may improve aerobic capacity and exercise tolerance during high-intensity CWRs in MM patients with CPEO.

Effect of L-carnitine on exercise performance in patients with mitochondrial myopathy.

Exercise intolerance due to impaired oxidative metabolism is a prominent symptom in patients with mitochondrial myopathy (MM), but it is still uncertain whether L-carnitine supplementation is beneficial for patients with MM. The aim of our study was to investigate the effects of L-carnitine on exercise performance in MM. Twelve MM subjects (mean age±SD=35.4±10.8 years) with chronic progressive external ophthalmoplegia (CPEO) were first compared to 10 healthy controls (mean age±SD=29±7.8 years) before they were randomly assigned to receive L-carnitine supplementation (3 g/daily) or placebo in a double-blind crossover design. Clinical status, body composition, respiratory function tests, peripheral muscle strength (isokinetic and isometric torque) and cardiopulmonary exercise tests (incremental to peak exercise and at 70% of maximal), constant work rate (CWR) exercise test, to the limit of tolerance [Tlim]) were assessed after 2 months of L-carnitine/placebo administration. Patients with MM presented with lower mean height, total body weight, fat-free mass, and peripheral muscle strength compared to controls in the pre-test evaluation. After L-carnitine supplementation, the patients with MM significantly improved their Tlim (14±1.9 vs 11±1.4 min) and oxygen consumption ( V ˙ O 2 ) at CWR exercise, both at isotime (1151±115 vs 1049±104 mL/min) and at Tlim (1223±114 vs 1060±108 mL/min). These results indicate that L-carnitine supplementation may improve aerobic capacity and exercise tolerance during high-intensity CWRs in MM patients with CPEO.

Dynamics of chest wall volume regulation during constant work rate exercise in patients with chronic obstructive pulmonary disease.

This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(V CW) = rib cage (V RC) + abdomen (V AB)] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinflation was considered to be present when end-expiratory (EE) V CW increased in relation to resting values. There was a noticeable heterogeneity in the patterns of V CW regulation as EEV CW increased non-linearly in 17/30 "hyperinflators" and decreased in 13/30 "non-hyperinflators" (P < 0.05). EEV AB decreased slightly in 8 of the "hyperinflators", thereby reducing and slowing the rate of increase in end-inspiratory (EI) V CW (P < 0.05). In contrast, decreases in EEV CW in the "non-hyperinflators" were due to the combination of stable EEV RC with marked reductions in EEV AB. These patients showed lower EIV CW and end-exercise dyspnea scores but longer Tlim than their counterparts (P < 0.05). Dyspnea increased and Tlim decreased non-linearly with a faster rate of increase in EIV CW regardless of the presence or absence of dynamic hyperinflation (P < 0.001). However, no significant between-group differences were observed in metabolic, pulmonary gas exchange and cardiovascular responses to exercise. Chest wall volumes are continuously regulated during exercise in order to postpone (or even avoid) their migration to higher operating volumes in patients with COPD, a dynamic process that is strongly dependent on the behavior of the abdominal compartment.

Dynamics of chest wall volume regulation during constant work rate exercise in patients with chronic obstructive pulmonary disease

This study evaluated the dynamic behavior of total and compartmental chest wall volumes [(V CW) = rib cage (V RC) + abdomen (V AB)] as measured breath-by-breath by optoelectronic plethysmography during constant-load exercise in patients with stable chronic obstructive pulmonary disease. Thirty males (GOLD stages II-III) underwent a cardiopulmonary exercise test to the limit of tolerance (Tlim) at 75% of peak work rate on an electronically braked cycle ergometer. Exercise-induced dynamic hyperinflation was considered to be present when end-expiratory (EE) V CW increased in relation to resting values. There was a noticeable heterogeneity in the patterns of V CW regulation as EEV CW increased non-linearly in 17/30 "hyperinflators" and decreased in 13/30 "non-hyperinflators" (P < 0.05). EEV AB decreased slightly in 8 of the "hyperinflators", thereby reducing and slowing the rate of increase in end-inspiratory (EI) V CW (P < 0.05). In contrast, decreases in EEV CW in the "non-hyperinflators" were due to the combination of stable EEV RC with marked reductions in EEV AB. These patients showed lower EIV CW and end-exercise dyspnea scores but longer Tlim than their counterparts (P < 0.05). Dyspnea increased and Tlim decreased non-linearly with a faster rate of increase in EIV CW regardless of the presence or absence of dynamic hyperinflation (P < 0.001). However, no significant between-group differences were observed in metabolic, pulmonary gas exchange and cardiovascular responses to exercise. Chest wall volumes are continuously regulated during exercise in order to postpone (or even avoid) their migration to higher operating volumes in patients with COPD, a dynamic process that is strongly dependent on the behavior of the abdominal compartment.

Relationship between work rate and oxygen uptake in mitochondrial myopathy during ramp-incremental exercise.

We determined the response characteristics and functional correlates of the dynamic relationship between the rate (Δ) of oxygen consumption (VO(2)) and the applied power output (work rate = WR) during ramp-incremental exercise in patients with mitochondrial myopathy (MM). Fourteen patients (7 males, age 35.4 ± 10.8 years) with biopsy-proven MM and 10 sedentary controls (6 males, age 29.0 ± 7.8 years) took a ramp-incremental cycle ergometer test for the determination of the VO(2) on-exercise mean response time (MRT) and the gas exchange threshold (GET). The ΔVO(2)/ΔWR slope was calculated up to GET (S(1)), above GET (S(2)) and over the entire linear portion of the response (S(T)). Knee muscle endurance was measured by isokinetic dynamometry. As expected, peak VO(2) and muscle performance were lower in patients than controls (P < 0.05). Patients had significantly lower ΔVO(2)/ΔWR than controls, especially the S(2) component (6.8 ± 1.5 vs 10.3 ± 0.6 mL·min(-1)·W(-1), respectively; P < 0.001). There were significant relationships between ΔVO(2)/ΔWR (S(T)) and muscle endurance, MRT-VO(2), GET and peak VO(2) in MM patients (P < 0.05). In fact, all patients with ΔVO(2)/ΔWR below 8 mL·min(-1)·W(-1) had severely reduced peak VO(2) values (<60% predicted). Moreover, patients with higher cardiopulmonary stresses during exercise (e.g., higher Δ ventilation/carbon dioxide output and Δ heart rate/ΔVO(2)) had lower ΔVO(2)/ΔWR (P < 0.05). In conclusion, a readily available, effort-independent index of aerobic dysfunction during dynamic exercise (ΔVO(2)/ΔWR) is typically reduced in patients with MM, being related to increased functional impairment and higher cardiopulmonary stress.

Relationship between work rate and oxygen uptake in mitochondrial myopathy during ramp-incremental exercise

We determined the response characteristics and functional correlates of the dynamic relationship between the rate (Δ) of oxygen consumption ( VO2) and the applied power output (work rate = WR) during ramp-incremental exercise in patients with mitochondrial myopathy (MM). Fourteen patients (7 males, age 35.4 ± 10.8 years) with biopsy-proven MM and 10 sedentary controls (6 males, age 29.0 ± 7.8 years) took a ramp-incremental cycle ergometer test for the determination of the VO2 on-exercise mean response time (MRT) and the gas exchange threshold (GET). The ΔVO2/ΔWR slope was calculated up to GET (S1), above GET (S2) and over the entire linear portion of the response (S T). Knee muscle endurance was measured by isokinetic dynamometry. As expected, peak VO2 and muscle performance were lower in patients than controls (P < 0.05). Patients had significantly lower ΔVO2/ΔWR than controls, especially the S2 component (6.8 ± 1.5 vs 10.3 ± 0.6 mL·min-1·W-1, respectively; P < 0.001). There were significant relationships between ΔVO2/ΔWR (S T) and muscle endurance, MRT-VO2, GET and peak VO2 in MM patients (P < 0.05). In fact, all patients with ΔVO2/ΔWR below 8 mL·min-1·W-1 had severely reduced peak VO2 values (<60 percent predicted). Moreover, patients with higher cardiopulmonary stresses during exercise (e.g., higher Δ ventilation/carbon dioxide output and Δ heart rate/ΔVO2) had lower ΔVO2/ΔWR (P < 0.05). In conclusion, a readily available, effort-independent index of aerobic dysfunction during dynamic exercise (ΔVO2/ΔWR) is typically reduced in patients with MM, being related to increased functional impairment and higher cardiopulmonary stress.

Respiratory muscle unloading improves leg muscle oxygenation during exercise in patients with COPD.

BACKGROUND: Respiratory muscle unloading during exercise could improve locomotor muscle oxygenation by increasing oxygen delivery (higher cardiac output and/or arterial oxygen content) in patients with chronic obstructive pulmonary disease (COPD). METHODS: Sixteen non-hypoxaemic men (forced expiratory volume in 1 s 42.2 (13.9)% predicted) undertook, on different days, two constant work rate (70-80% peak) exercise tests receiving proportional assisted ventilation (PAV) or sham ventilation. Relative changes (Delta%) in deoxyhaemoglobin (HHb), oxyhaemoglobin (O(2)Hb), tissue oxygenation index (TOI) and total haemoglobin (Hb(tot)) in the vastus lateralis muscle were measured by near-infrared spectroscopy. In order to estimate oxygen delivery (Do(2)est, l/min), cardiac output and oxygen saturation (Spo(2)) were continuously monitored by impedance cardiography and pulse oximetry, respectively. RESULTS: Exercise tolerance (Tlim) and oxygen uptake were increased with PAV compared with sham ventilation. In contrast, end-exercise blood lactate/Tlim and leg effort/Tlim ratios were lower with PAV (p<0.05). There were no between-treatment differences in cardiac output and Spo(2) either at submaximal exercise or at Tlim (ie, Do(2)est remained unchanged with PAV; p>0.05). Leg muscle oxygenation, however, was significantly enhanced with PAV as the exercise-related decrease in Delta(O(2)Hb)% was lessened and TOI was improved; moreover, Delta(Hb(tot))%, an index of local blood volume, was increased compared with sham ventilation (p<0.01). CONCLUSIONS: Respiratory muscle unloading during high-intensity exercise can improve peripheral muscle oxygenation despite unaltered systemic Do(2 )in patients with advanced COPD. These findings might indicate that a fraction of the available cardiac output had been redirected from ventilatory to appendicular muscles as a consequence of respiratory muscle unloading.

Methacholine vs adenosine on intra and extrathoracic airway hyperresponsiveness in patients with cough variant asthma.

BACKGROUND: Airway hyperresponsiveness (AHR) can be studied by bronchoprovocation test (BPT) using direct (methacholine - MCh) or indirect (adenosine 5'-monophosphate - AMP) stimuli. These two substances have not been compared in cough variant asthma (CVA). OBJECTIVE: We designed a randomized, single-blind, cross-over study to compare AMP and MCh in the detection of CVA. Additionally, we examined whether assessment of extrathoracic airway hyperresponsiveness (EAHR) during MCh and AMP helped in the evaluation of CVA. METHODS: Patients with CVA with previous positive MCh BPT performed challenges with AMP and MCh. The variables were: (i) a provocative dose producing a 20% fall in forced expiratory volume in 1 s (FEV(1)) value (PD(20)MCh); (ii) a provocative dose producing a 25% fall in the maximal mid-inspiratory flow (FIF(50)) from baseline (PD(25)MCh) for MCh; (iii) a provocative concentration producing a 20% fall in FEV(1) value (PC(20)AMP) and (iv) a provocative concentration producing a 25% fall in the FIF(50) from baseline (PC(25)AMP) for AMP. RESULTS: All 113 patients with CVA responded to PD(20)MCh and 96% and 69% responded to PC(20)AMP, if we used PC(20)

A step test to assess exercise-related oxygen desaturation in interstitial lung disease.

A 6-min step test (6MST) may constitute a practical method for routinely assessing effort tolerance and exercise-related oxyhaemoglobin desaturation (ERD) in the primary care of patients with interstitial lung disease. In total, 31 patients (19 males) with idiopathic pulmonary fibrosis (n = 25) and chronic hypersensitivity pneumonia were submitted, on different days, to two 6MSTs. Physiological responses were compared with those found on maximal and submaximal cycle ergometer tests at the same oxygen uptake (V'(O(2))). Chronic breathlessness was also determined, as measured by the baseline dyspnoea index (BDI). Responses to 6MST were highly reproducible: 1.3+/-2.0 steps x min(-1), +/-5 beats x min(-1) (cardiac frequency), +/-50 mL x min(-1) (V'(O(2))), +/-7 L x min(-1) (minute ventilation) and +/-2% (arterial oxygen saturation measured by pulse oximetry (S(p,O(2)))). The number of steps climbed in 6 min was correlated to peak V'(O(2)) and the BDI. There were significant associations among the tests in relation to presence (change in S(p,O(2)) between rest and exercise > or = 4%) and severity (S(p,O(2)) <88%) of ERD. Four patients, however, presented ERD only in response to 6MST. Resting diffusing capacity of the lung for carbon monoxide and alveolar-arterial oxygen tension difference were the independent predictors of the number of steps climbed. A single-stage, self-paced 6-min step test provided reliable and reproducible estimates of exercise capacity and exercise-related oxyhaemoglobin desaturation in interstitial lung disease patients.

Inspiratory fraction and exercise impairment in COPD patients GOLD stages II-III.

The inspiratory-to-total lung capacity ratio or "inspiratory fraction" (inspiratory capacity(IC)/total lung capacity (TLC)) may be functionally more representative than traditional indices of resting airflow limitation and lung hyperinflation in patients with chronic obstructive pulmonary disease (COPD). In the present retrospective study, a comparison was made of the individual performance of post-bronchodilator IC, IC/TLC and forced expiratory volume in one second (FEV(1)) in predicting a severely reduced peak oxygen uptake (V'(O(2)); <60% predicted) in 44 COPD patients Global Initiative for Chronic Obstructive Lung Disease stages II-III (post-bronchodilator FEV(1) ranging from 31-79% pred). Patients with lower IC/TLC values (

A prospective longitudinal study of clinical characteristics, laboratory findings, diagnostic spectrum and outcomes of specific therapy in adult patients with chronic cough in a general respiratory clinic.

Chronic cough with established diagnostic protocols has been well described in secondary and tertiary centres. Little information is available about adult patients to a general respiratory clinic where no such protocols exist. The objective of this study is to determine clinical characteristics, laboratory findings, diagnostic spectrum and outcomes of specific therapy in adult patients with chronic cough in a general respiratory clinic. In this prospective, longitudinal, descriptive study for patients with chronic cough defined as more than 8 weeks, we studied, according to a questionnaire, chest radiography, spirometry and reversibility, methacholine challenge and other measures. Treatment was prescribed on the basis of diagnosis informed by investigation results.We evaluated 147 patients (102 females) of a mean age of 48 years and complaining of cough an average of 24 weeks. On the basis of a successful response to treatment, the causes of cough were determined in 92% and the frequencies were asthma in 39%, COPD in 11%, chronic upper airway cough syndrome (CUACS) in 9%, gastro-oesophageal reflux disease (GERD) in 9% and no diagnosis in 8%. Cough was due to one condition in 82%. Our treatment success rate was 92%. The most frequent causes of chronic cough (asthma, COPD, CUACS and GERD) could be determined in a general respiratory clinic with a sequential approach. The frequencies are different from those in a tertiary cough clinic, but outcome of specific therapy is successful in our patients.

Importance of cholinesterase kinetic parameters in environmental monitoring using estuarine fish.

The aim of the present study was to determine the kinetic parameters and cholinesterase (ChE) activity in two teleost fish, the white mouth croaker Micropogonias furnieri (Scianidae) and the Madamango sea catfish Cathorops spixii (Ariidae), to verify their suitability as sentinel species of aquatic pollution by anticholinergic compounds. Individuals of each species were captured in one reference and one polluted site in the Southern Brazilian coast. Brain tissue was used as enzyme source. Inhibition kinetic parameters indicated that ChE from C. spixii collected at the reference site showed more affinity (Ka) for eserine that from those collected at the polluted site. The opposite was observed for the carbamylation constants (Kc). Thus, similar inhibition constants (Ki) were observed. M. furnieri brain showed an extremely low sensitivity to in vitro inhibition by eserine, indicating that it is not a suitable biomarker to be employed in environmental monitoring of anticholinergic compounds. Results from the present study also point to the need for considering kinetic analysis when cholinesterase activity is employed as a biomarker.

[Asbestos-related pleuropulmonary diseases: pictorial essay]. / Alterações pleurais e parenquimatosas relacionadas com a exposição ao asbestos: ensaio pictórico.

Pleural and pulmonary asbestos-related diseases range from benign conditions, like pleural effusion and pleural plaques, to some neoplasias, such as lung cancer and malignant mesothelioma. Pleural effusion is the earliest finding after asbestos exposure, but the imaging findings are not specific. Diffuse pleural thickening involves the visceral pleura and pleural plaques are considered to be hallmarks of exposure. Asbestosis is the pulmonary fibrosis due to asbestos. Rounded atelectasis is a peripheral lung collapse in these individuals, generally related to pleural disease. Some neoplasias, like lung carcinoma and pleural mesothelioma, are more prevalent in asbestos-exposed subjects. The aim of this essay is to illustrate the main imaging findings of asbestos-related diseases.

[Asbestos-related pleural plaques: a literature review]. / Placas pleurais relacionadas ao asbesto: revisão da literatura.

Pleural plaques (PP) are considered to be hallmarks of asbestos exposure. They constitute focal thickenings of the pleura and are commonly seen in patients without lung disease. They can involve parietal, diaphragmatic and mediastinal pleura. Chest x-ray is frequently used for PP diagnosis, but computed tomography, especially when used the high-resolution technique, is the imaging exam with the greatest sensibility and specificity. PP are almost always asymptomatic, but there are some controversial about their relationship with asbestos exposure indexes, pulmonary functional alterations and risk of neoplasias.

Non-malignant consequences of decreasing asbestos exposure in the Brazil chrysotile mines and mills.

AIMS: To investigate the consequences of improvement in the workplace environment over six decades (1940-96) in asbestos miners and millers from a developing country (Brazil). METHODS: A total of 3634 Brazilian workers with at least one year of exposure completed a respiratory symptoms questionnaire, chest radiography, and a spirometric evaluation. The study population was separated into three groups whose working conditions improved over time: group I (1940-66, n = 180), group II (1967-76, n = 1317), and group III (1977-96, n = 2137). RESULTS: Respiratory symptoms were significantly related to spirometric abnormalities, smoking, and latency time. Breathlessness, in particular, was also associated with age, pleural abnormality and increased cumulative exposure to asbestos fibres. The odds ratios (OR) for parenchymal and/or non-malignant pleural disease were significantly lower in groups II and III compared to group I subjects (0.29 (0.12-0.69) and 0.19 (0.08-0.45), respectively), independent of age and smoking status. Similar results were found when groups were compared at equivalent latency times (groups I v II: 30-45 years; groups II v III: 20-25 years). Ageing, dyspnoea, past and current smoking, and radiographic abnormalities were associated with ventilatory impairment. Lower spirometric values were found in groups I and II compared to group III: lung function values were also lower in higher quartiles of latency and of cumulative exposure in these subjects. CONCLUSIONS: Progressive improvement in occupational hygiene in a developing country is likely to reduce the risk of non-malignant consequences of dust inhalation in asbestos miners and millers.

Identification of rounded atelectasis in workers exposed to asbestos by contrast helical computed tomography

Rounded atelectasis (RA) is a benign and unusual form of subpleural lung collapse that has been described mostly in asbestos-exposed workers. This form of atelectasis manifests as a lung nodule and can be confused with bronchogenic carcinoma upon conventional radiologic examination. The objective of the present study was to evaluate the variation in contrast uptake in computed tomography for the identification of asbestos-related RA in Brazil. Between January 1998 and December 2000, high-resolution computed tomography (HRCT) was performed in 1658 asbestos-exposed workers. The diagnosis was made in nine patients based on a history of prior asbestos exposure, the presence of characteristic (HRCT) findings and lesions unchanged in size over 2 years or more. In three of them the diagnosis was confirmed during surgery. The dynamic contrast enhancement study was modified to evaluate nodules and pulmonary masses. All nine patients with RA received iodide contrast according to weight. The average enhancement after iodide contrast was infused, reported as Hounsfield units (HU), increased from 62.5 ± 9.7 to 125.4 ± 20.7 (P < 0.05), with a mean enhancement of 62.5 ± 19.7 (range 40 to 89) and with a uniform dense opacification. In conclusion, in this study all patients with RA showed contrast enhancement with uniform dense opacification. The main clinical implication of this finding is that this procedure does not permit differentiation between RA and malignant pulmonary neoplasm