Objective: To evaluate the contribution of a new coefficient, the FEF50%/0.5FVC ratio, obtained from the maximal expiratory flow-volume curve, to the diagnosis of obstructive lung disease (OLD); to test this coefficient in differentiating among patients considered normal, those with OLD and those with restrictive lung disease (RLD); and to determine cut-off points for each functional diagnosis, as well as the probability for each diagnosis based on individual values. Methods: A prospective, cross-sectional study analyzing the pulmonary function of patients referred to the Porto Alegre Hospital de Clínicas, in Porto Alegre, Brazil, between January and December of 2003. We collected demographic and spirometric data. The patients were divided into three groups: normal; OLD; and RLD. We calculated the FEV1/FVC and FEF50%/0.5FVC ratios, and we compared the mean FEF50%/0.5FVC values among the groups. We used Pearson's correlation test in order to compare FEF50%/0.5FVC with FEV1/FVC. The patients were again divided into two groups: those with OLD and those without OLD. We calculated the likelihood ratio for different cut-off points. Results: The mean age of the patients was 55.8 ± 14.7 years. There were significant differences among the groups in terms of the mean FEF50%/0.5FVC (2.10 ± 0.82, 2.55 ± 1.47 and 0.56 ± 0.29, respectively, for normal, RLD and OLD; p < 0.001). There was a positive correlation between FEF50%/0.5FVC and FEV1/FVC in the OLD group (r = 0.83). We found that an FEF50%/0.5FVC < 0.79 strongly suggests OLD, whereas an FEF50%/0.5FVC > 1.33 practically excludes this diagnosis. Conclusions: The FEF50%/0.5FVC ratio is a potentially useful parameter in the differential diagnosis of OLD and correlates positively with the FEV1/FVC ratio.

Keywords: Pulmonary disease, chronic obstructive; Spirometry; Respiratory function tests.

The role of immunohistochemistry is to recognize antigens and, consequently, to identify and classify specific cells within a cell population whose morphology is heterogenous or apparently homogenous. The visualization of the antigen-antibody complex is made possible through the addition of either a fluorochrome conjugate or an enzyme to the antibody, which is then viewed under microscopy. Immunohistochemistry can be used in the routine diagnosis of lung cancer, in order to identify biological markers (diagnostic and prognostic). The essential immunohistochemistry panels will be discussed in this review.

Keywords: Immunohistochemistry; Tumor markers, biological; Lung neoplasms.

Objective: To evaluate the accuracy of determining the adenosine deaminase (ADA) level, the 2'-deoxyadenosine/ADA ratio, and the LDH/ADA ratio in pleural fluid for the diagnosis of pleural tuberculosis (PT) in children and adolescents. Methods: This was a retrospective cross-sectional study conducted at a tertiary hospital in a high-tuberculosis-incidence area, between 2001 and 2018. All patients with ADA in pleural fluid and a confirmed diagnosis of PT (cPT) or parapneumonic effusion (PPE) were included. Results: The cPT and PPE groups comprised 25 and 68 individuals, respectively. At a cutoff of 40 U/L, ADA measurement showed the following: sensitivity, 88%; specificity, 31%; positive predictive value (PPV), 32%; negative predictive value (NPV), 88%; and overall accuracy, 46%. The best cutoffs were an ADA level of 125 U/L, a 2'-deoxyadenosine/ADA ratio of 0.5, and an LDH/ADA ratio of 8.3, with AUC of 0.67, 0.75, and 0.82, respectively. The sensitivity, specificity, PPV, NPV, and overall accuracy of the 125 U/L ADA cutoff were 84%, 65%, 47%, 92%, and 70%, respectively, compared with 79%, 79%, 59%, 91%, and 79%, respectively, for the 8.3 LDH/ADA ratio cutoff. Changing the LDH/ADA ratio cutoff to 3.0 increased the specificity to 98%. Conclusions: The ADA level and the 2'-deoxyadenosine/ADA ratio are not good biomarkers for the diagnosis of PT in pediatric patients. Determination of the LDH/ADA ratio provides the best overall accuracy for the diagnosis of PT in such patients.

Keywords: Adenosine deaminase; Pleural effusion; Tuberculosis, pleural/diagnosis; Child; Adolescent.

Objective: To analyze the relationship between one-minute sit-to-stand test (1MSTST) parameters and a diagnosis of post COVID-19 condition in a cohort of patients who previously had COVID-19. Methods: This was a prospective cohort study of patients with post COVID-19 condition referred for body plethysmography at a tertiary university hospital. Post COVID-19 condition was defined in accordance with the current WHO criteria. Results: Fifty-three patients were analyzed. Of those, 25 (47.2%) met the clinical criteria for post COVID-19 condition. HR was lower in the patients with post COVID-19 condition than in those without it at 30 s after initiation of the 1MSTST (86.2 ± 14.3 bpm vs. 101.2 ± 14.7 bpm; p < 0.001) and at the end of the test (94.4 ± 18.2 bpm vs. 117.3 ± 15.3 bpm; p < 0.001). The ratio between HR at the end of the 1MSTST and age-predicted maximal HR (HRend/HRmax) was lower in the group of patients with post COVID-19 condition (p < 0.001). An HRend/HRmax of < 62.65% showed a sensitivity of 78.6% and a specificity of 82.0% for post COVID-19 condition. Mean SpO2 at the end of the 1MSTST was lower in the patients with post COVID-19 condition than in those without it (94.9 ± 3.6% vs. 96.8 ± 2.4%; p = 0.030). The former group of patients did fewer repetitions on the 1MSTST than did the latter (p = 0.020). Conclusions: Lower SpO2 and HR at the end of the 1MSTST, as well as lower HR at 30 s after initiation of the test, were associated with post COVID-19 condition. In the appropriate clinical setting, an HRend/HRmax of < 62.65% should raise awareness for the possibility of post COVID-19 condition.

Keywords: COVID-19; Post-acute COVID-19 syndrome; Heart rate; Respiratory function tests.

Objective: To determine the interobserver and intraobserver agreement in the diagnosis of interstitial lung diseases (ILDs) based on HRCT scans and the impact of observer expertise, clinical data and confidence level on such agreement. Methods: Two thoracic radiologists and two general radiologists independently reviewed the HRCT images of 58 patients with ILDs on two distinct occasions: prior to and after the clinical anamnesis. The radiologists selected up to three diagnostic hypotheses for each patient and defined the confidence level for these hypotheses. One of the thoracic and one of the general radiologists re-evaluated the same images up to three months after the first readings. In the coefficient analyses, the kappa statistic was used. Results: The thoracic and general radiologists, respectively, agreed on at least one diagnosis for each patient in 91.4% and 82.8% of the patients. The thoracic radiologists agreed on the most likely diagnosis in 48.3% (κ = 0.42) and 62.1% (κ = 0.58) of the cases, respectively, prior to and after the clinical anamnesis; likewise, the general radiologists agreed on the most likely diagnosis in 37.9% (κ = 0.32) and 36.2% (κ = 0.30) of the cases. For the thoracic radiologist, the intraobserver agreement on the most likely diagnosis was 0.73 and 0.63 prior to and after the clinical anamnesis, respectively. That for the general radiologist was 0.38 and 0.42.The thoracic radiologists presented almost perfect agreement for the diagnostic hypotheses defined with the high confidence level. Conclusions: Interobserver and intraobserver agreement in the diagnosis of ILDs based on HRCT scans ranged from fair to almost perfect and was influenced by radiologist expertise, clinical history and confidence level.

Keywords: Lung diseases, interstitial; Tomography, X-ray computed; Observer variation.

Introduction: Bronchoscopy is useful in the diagnosis of tuberculosis suspects with a "negative" sputum smear. The objectives of this study were: to assess yield of bronchoalveolar lavage (BAL) and of transbronchial biopsy (TBB) both in HIV-positive patients (group 1) and immunocompetent individuals (group 2), based on simple and most available laboratory techniques in clinical practice. Patients and methods: The authors performed 319 bronchoscopies in 302 patients. BAL and TBB were sequentially performed in the same lung in all cases. Tuberculosis was diagnosed based on the results of acid-fast stains (AFS) from the lavage (ZN), culture for mycobacteria (LJ), and histological examination of biopsies (HE and ZN). Results: Tuberculosis was the final diagnosis in 28 exams of group 1 (n = 214) and in 35 of group 2 (n = 105). There were abnormal endoscopic findings respectively in 3 and 10 patients. In group 1, AFS were positive in 7 cases, culture of BAL in 14, and TBB in 19. In group 2, AFS were positive in 13 cases, culture in 17, and biopsies in 31. TBB results compared to BAL were in concordance for group 1 (p = 0.823) and different for group 2 (p = 0.022). Immediate results (AFS and TBB) compared to later positive results of culture were similar for group 1 (p = 0.066) but not for group 2 (p = 0.001). There were eight episodes of pneumothorax (2.5%) and one death (0.36%). Conclusions: Both BAL and TBB should be performed whenever possible, aiming towards a higher yield of bronchoscopy in the diagnosis of tuberculosis. Both methods complement each other in immunocompetent patients, whereas TBB establishes a faster diagnosis for HIV-infected patients if associated to AFS.

Keywords: Bronchoscopy/methods. Smear-negative tuberculosis/diagnosis. Opportunistic infections related to AIDS/diagnosis.

Biological markers are cellular, structural and biochemical components that can define cellular as well as molecular changes in both normal and neoplastic cells. There are two types of biological markers: 1) intermediate markers that evaluate cellular and molecular alterations before malignancy occurs; and 2) diagnostic markers, present in association with malignancy. The identification and validation of biological markers for clinical use are performed in stages: initial identification in cell cultures of the tumor;
testing of the marker in tissues obtained in biopsies of patients with an established diagnosis of the tumor;
testing of biopsies of normal tissues and tissues with an inflammatory process;
sputum, blood or urine tests for validation as a non-invasive test that can be used in high-risk populations. Sorologic and histopathologic biological markers are cellular, structural and biochemical components found in both normal and neoplastic cells that can be quantitatively assessed by biochemical, immunological and molecular methods in the body fluids or tissues, respectively, and may be associated with malignancies and, possibly, with the neoplastic organ. Biological markers are studied in diverse primary neoplasms. However, few of them proved to be clinically valuable. The role of biological markers in lung cancer patients remains unclear because only a small number of markers has been properly identifiassessed. The aim of this paper is to understand the role of sorologic and histologic biological markers in the prognosis and survival of lung cancer patients based on our previous works. Furthermore, we present a future perspective of the early detection of lung cancer on the basis of the role of intermediate biological markers.

Keywords: Biologic markers. Lung cancer. Prognosis. Survival. Morphometric method.

Obstructive sleep apnea (OSA) is a common clinical condition, with a variable and underestimated prevalence. OSA is the main condition associated with secondary systemic arterial hypertension, as well as with atrial fibrillation, stroke, and coronary artery disease, greatly increasing cardiovascular morbidity and mortality. Treatment with continuous positive airway pressure is not tolerated by all OSA patients and is often not suitable in cases of mild OSA. Hence, alternative methods to treat OSA and its cardiovascular consequences are needed. In OSA patients, regular physical exercise has beneficial effects other than weight loss, although the mechanisms of those effects remain unclear. In this population, physiological adaptations due to physical exercise include increases in upper airway dilator muscle tone and in slow-wave sleep time; and decreases in fluid accumulation in the neck, systemic inflammatory response, and body weight. The major benefits of exercise programs for OSA patients include reducing the severity of the condition and daytime sleepiness, as well as increasing sleep efficiency and maximum oxygen consumption. There are few studies that evaluated the role of physical exercise alone for OSA treatment, and their protocols are quite diverse. However, aerobic exercise, alone or combined with resistance training, is a common point among the studies. In this review, the major studies and mechanisms involved in OSA treatment by means of physical exercise are presented. In addition to systemic clinical benefits provided by physical exercise, OSA patients involved in a regular, predominantly aerobic, exercise program have shown a reduction in disease severity and in daytime sleepiness, as well as an increase in sleep efficiency and in peak oxygen consumption, regardless of weight loss.

Keywords: Exercise therapy; Sleep apnea, obstructive; Cardiovascular diseases.

This paper reviews in brief the role of nitric oxide in the respiratory physiology and in the pathology of some pulmonary diseases. The potential diagnostic and monitoring uses in several clinical situations are also discussed.

Keywords: respiratory tract diseases; lung diseases, obstructive; asthma; smoking; cystic fibrosis; bronchiectasis lung; lung transplantation

Knowledge of the structure and function of pulmonary circulation has evolved considerably in the last few decades. The use of non-invasive imaging techniques to assess the anatomy and function of the pulmonary vessels and heart has taken on added importance with the recent advent of novel therapies. Imaging findings not only constitute a diagnostic tool but have also proven to be essential for prognosis and treatment follow-up. This article reviews the myriad of imaging methods currently available for the assessment of pulmonary circulation, from the simple chest X-ray to techniques that are more complex and promising, such as electrical impedance tomography.

Keywords: Pulmonary circulation; Diagnostic imaging; Hypertension, pulmonary.

In many populations, the prevalence of asthma and atopy has increased in recent years. As a result, both conditions have become major public health problems. The possible influence of nutrition-related factors has been demonstrated in an increasing number of studies. Information regarding the role of breastfeeding, diet, nutritional status (obesity in particular), as well as regarding the immunologic responses triggered, helps to improve our understanding of the correlation between oxidative stress, bronchial inflammation, and the development of atopic and asthma symptoms. The article presents a review of the published literature on the relationships established between and among nutrition, asthma, and atopy over the last two decades.

Keywords: Asthma; Nutritional status; Breast feeding; Diet.