Effects of positive expiratory pressure on pulmonary clearance of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid in healthy individuals / Efeitos da pressão expiratória positiva na depuração pulmonar do ácido dietilenotriaminopentacético marcado com tecnécio-99m em aerossol em indivíduos saudáveis

ABSTRACT Objective: To evaluate the effects of positive expiratory pressure (PEP) on pulmonary epithelial membrane permeability in healthy subjects. Methods: We evaluated a cohort of 30 healthy subjects (15 males and 15 females) with a mean age of 28.3 ± 5.4 years, a mean FEV1/FVC ratio of 0.89 ± 0.14, and a mean FEV1 of 98.5 ± 13.1% of predicted. Subjects underwent technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) radioaerosol inhalation lung scintigraphy in two stages: during spontaneous breathing; and while breathing through a PEP mask at one of three PEP levels-10 cmH2O (n = 10), 15 cmH2O (n = 10), and 20 cmH2O (n = 10). The 99mTc-DTPA was nebulized for 3 min, and its clearance was recorded by scintigraphy over a 30-min period during spontaneous breathing and over a 30-min period during breathing through a PEP mask. Results: The pulmonary clearance of 99mTc-DTPA was significantly shorter when PEP was applied-at 10 cmH2O (p = 0.044), 15 cmH2O (p = 0.044), and 20 cmH2O (p = 0.004)-in comparison with that observed during spontaneous breathing. Conclusions: Our findings indicate that PEP, at the levels tested, is able to induce an increase in pulmonary epithelial membrane permeability and lung volume in healthy subjects.

RESUMO Objetivo: Avaliar os efeitos da pressão expiratória positiva (PEP) na permeabilidade da membrana epitelial pulmonar em indivíduos saudáveis. Métodos: Foi avaliada uma coorte de 30 indivíduos saudáveis (15 homens e 15 mulheres), com média de idade de 28,3 ± 5,4 anos, média da relação VEF1/CVF de 0,89 ± 0,14 e média de VEF1 de 98,5 ± 13,1% do previsto. Os indivíduos foram submetidos a cintilografia pulmonar por inalação de radioaerossol de ácido dietilenotriaminopentacético marcado com tecnécio-99m (99mTc-DTPA em inglês) em dois estágios: durante respiração espontânea e durante respiração com uma máscara de PEP de 10 cmH2O (n = 10), 15 cmH2O (n = 10) ou 20 cmH2O (n = 10). O 99mTc-DTPA foi nebulizado por 3 min, e sua depuração foi registrada por cintilografia por um período de 30 min durante respiração espontânea e por um período de 30 min durante a respiração com uma máscara de PEP. Resultados: A depuração pulmonar do 99mTc-DTPA foi significativamente menor quando PEP foi aplicada a 10 cmH2O (p = 0,044), 15 cmH2O (p = 0,044) e 20 cmH2O (p = 0,004), em comparação com a observada durante a respiração espontânea. Conclusões: Nossos achados indicam que o uso de PEP nos níveis testados pode induzir um aumento na permeabilidade da membrana epitelial pulmonar e no volume pulmonar em indivíduos saudáveis.

Effects of positive expiratory pressure on pulmonary clearance of aerosolized technetium-99m-labeled diethylenetriaminepentaacetic acid in healthy individuals.

OBJECTIVE:: To evaluate the effects of positive expiratory pressure (PEP) on pulmonary epithelial membrane permeability in healthy subjects. METHODS:: We evaluated a cohort of 30 healthy subjects (15 males and 15 females) with a mean age of 28.3 ± 5.4 years, a mean FEV1/FVC ratio of 0.89 ± 0.14, and a mean FEV1 of 98.5 ± 13.1% of predicted. Subjects underwent technetium-99m-labeled diethylenetriaminepentaacetic acid (99mTc-DTPA) radioaerosol inhalation lung scintigraphy in two stages: during spontaneous breathing; and while breathing through a PEP mask at one of three PEP levels-10 cmH2O (n = 10), 15 cmH2O (n = 10), and 20 cmH2O (n = 10). The 99mTc-DTPA was nebulized for 3 min, and its clearance was recorded by scintigraphy over a 30-min period during spontaneous breathing and over a 30-min period during breathing through a PEP mask. RESULTS:: The pulmonary clearance of 99mTc-DTPA was significantly shorter when PEP was applied-at 10 cmH2O (p = 0.044), 15 cmH2O (p = 0.044), and 20 cmH2O (p = 0.004)-in comparison with that observed during spontaneous breathing. CONCLUSIONS:: Our findings indicate that PEP, at the levels tested, is able to induce an increase in pulmonary epithelial membrane permeability and lung volume in healthy subjects. OBJETIVO:: Avaliar os efeitos da pressão expiratória positiva (PEP) na permeabilidade da membrana epitelial pulmonar em indivíduos saudáveis. MÉTODOS:: Foi avaliada uma coorte de 30 indivíduos saudáveis (15 homens e 15 mulheres), com média de idade de 28,3 ± 5,4 anos, média da relação VEF1/CVF de 0,89 ± 0,14 e média de VEF1 de 98,5 ± 13,1% do previsto. Os indivíduos foram submetidos a cintilografia pulmonar por inalação de radioaerossol de ácido dietilenotriaminopentacético marcado com tecnécio-99m (99mTc-DTPA em inglês) em dois estágios: durante respiração espontânea e durante respiração com uma máscara de PEP de 10 cmH2O (n = 10), 15 cmH2O (n = 10) ou 20 cmH2O (n = 10). O 99mTc-DTPA foi nebulizado por 3 min, e sua depuração foi registrada por cintilografia por um período de 30 min durante respiração espontânea e por um período de 30 min durante a respiração com uma máscara de PEP. RESULTADOS:: A depuração pulmonar do 99mTc-DTPA foi significativamente menor quando PEP foi aplicada a 10 cmH2O (p = 0,044), 15 cmH2O (p = 0,044) e 20 cmH2O (p = 0,004), em comparação com a observada durante a respiração espontânea. CONCLUSÕES:: Nossos achados indicam que o uso de PEP nos níveis testados pode induzir um aumento na permeabilidade da membrana epitelial pulmonar e no volume pulmonar em indivíduos saudáveis.

Correlation between Breslow thickness and Technetium-99m-sestamibi uptake in cutaneous melanoma.

BACKGROUND: Technetium-99m-sestamibi (MIBI) is a radiopharmaceutical that has well-known tumor-seeking properties. We evaluated the correlation between Breslow thickness and MIBI uptake by cutaneous melanoma (CM). MATERIAL AND METHODS: Patients with suspicious melanocytic lesions received intravenous injections of 740-1,110 Mbq of MIBI. Using a gamma probe, the number of radioactive counts in the skin was considered to determinate the MIBI uptake intensity. SPECT imaging of the lesion site and respective lymph node region was obtained. RESULTS: There was a strong positive correlation between MIBI uptake intensity and Breslow thickness (rs = 0.74, P = 0.003). There was a statistically significant difference (P <0.001) between lesions with Breslow thickness <1 mm (MIBI uptake intensity = 1.23 ± 0.28 radioactive counts) and Breslow thickness >1 mm (MIBI uptake intensity = 2.32 ± 0.32 radioactive counts). DISCUSSION: The possibility of correlating MIBI uptake intensity with Breslow categories may facilitate surgical procedures, reducing morbidity and costs.

Perfused lung volume to thoracic gas volume ratio (perfused lung fraction) in patients with COPD and in controls.

BACKGROUND: The deterioration of the ventilation-to-perfusion distribution in patients with chronic obstructive pulmonary disease (COPD) reflects structural changes affecting both the airways and the blood vessels. These changes result in lung perfusion abnormalities that may be quantified by lung perfusion single photon emission computed tomography (SPECT). OBJECTIVE: To compare the perfused lung fraction (PLF) in patients with airflow obstruction and controls. METHODS: Fourteen patients with COPD and 21 controls underwent spirometry, whole-body plethysmography, and lung perfusion SPECT. PLF was derived from the ratio of perfused lung volume (measured by SPECT) to thoracic gas volume (measured by whole-body plethysmography). RESULTS: In the whole study sample, there were 18 (51%) women and 17 (49%) men, mean age was 46.2 (±20.3) years, range: 18-80 years). In the COPD group, PLF was 0.74 (±0.08), whereas in the control group PLF was 0.99 (±0.18) (P<0.001). PLF correlated directly with forced expiratory volume in 1 s to forced vital capacity (r=0.597, P<0.001). Perfused lung volume was 3.66 (±0.64) l in the COPD group compared with 2.71 (±0.70) l in the control group (P<0.001). CONCLUSION: The fraction of lung volume receiving blood from the pulmonary artery is reduced in patients with COPD. The degree of underperfusion seems to correlate with the degree of airflow limitation.

Quantitative parameters for the assessment of renal scintigraphic images.

Renal scintigraphy is a well-established functional technique for the visual evaluation of the renal cortical mass. It allows the visualization of the radiopharmaceutical tracer distribution, the size, shape, symmetry, and position of the kidneys. However, the (visual) analysis of these images tend to be subjective, causing significant variability in the interpretation of findings. This paper proposes objective measures that reflect common findings observed in those images, and potentially can minimize the inter-observer variability. We also propose a segmentation method specific for renal scintigraphic images. Our preliminary experiments indicate that our proposed features agree in at least 90% of the cases with the specialists visual evaluation.

Comparação da linfocintilografia com dextrano 500 com a do fitato na pesquisa do linfonodo sentinela no câncer de mama / Lymphoscintigraphy imaging study for sentinel node mapping, comparing dextran 500 with phytate, in breast cancer patients

OBJETIVO: comparar a acurácia de dois radiocolóides na marcação do linfonodo sentinela (LNS) por imagem. MÉTODOS: as pacientes foram incluídas no período de maio de 2002 a abril de 2004. Neste estudo duplo-cego, a paciente foi submetida duas vezes ao mesmo exame, mas com fármacos diferentes, sendo que os fármacos, tecnécio-99m-dextrano 500 (dextrano) e tecnécio-99m-fitato (fitato), foram injetados, na mama, em quatro pontos na área peritumoral e no subcutâneo superficialmente ao tumor, com volume de 2 ml, contendo de 1,0 a 1,5 mCi, em alíquotas de 0,4 ml. Para a obtenção das imagens, duas horas após a injeção do radiofármaco, usamos gama-câmera com colimador de alta resolução. A drenagem linfática axilar foi identificada em imagens radiográficas estáticas, anterior e lateral. A estatística para pares discordantes foi realizada pelo teste de MacNemar e pelo teste Z para proporções. RESULTADOS: na análise das 40 pacientes, obtiveram-se 15 pares com imagens positivas iguais, 4 pares com imagens negativas e 21 pares com imagens distintas, seja porque uma era negativa, seja porque o número de LNS marcados era diferente. A análise do desempenho quanto ao sucesso e insucesso mostrou 35 e 27 imagens positivas e 5 e 13 imagens negativas, respectivamente para o dextrano e o fitato, sendo que das negativas 4 eram comuns. O estudo estatístico pelo teste de MacNemar mostrou p=0,026, com odds ratio (OR) = 0,11 e IC 95 por cento 0,01

Learning from panel boards: T-lymphocyte and B-lymphocyte self-tolerance game.

Immunology is a vast, complex and challenging subject. To facilitate students' understanding, the authors have created a T-lymphocyte and B-lymphocyte self-tolerance game. The T-lymphocyte self-tolerance game consisted of 24 cardboard pieces with illustrations and statements about self-tolerance mechanisms and one large panel board. The B-lymphocyte panel board consisted of 11 cardboard pieces with illustrations and statements about self-tolerance mechanisms, and two large panels. Students had to associate mechanisms of self-tolerance with the corresponding cardboard pieces. In total, 120 students attended the session. Of these, 95.8% considered that the panel board facilitated their understanding; 95% affirmed they understood how T- and B-lymphocyte self-tolerance worked. Students' grades improved significantly. The good results obtained show the value of using a panel board when approaching a subject that is vast and complex.