M.F. Baganha

NEOPTERIN IN TUBERCULOUS AND NEOPLASTIC PLEURAL FLUIDS

Neopterin is derived from guanosine-triphosphate, produced by stimulated macrophages under the influence of gamma interferon of lymphocyte origin. It has been suggested as an excellent marker for activation of the monocyte/macrophage axis in some clinical situations. We evaluated its concentration in the pleural effusions of 25 individuals (10 tuberculous and 15 neoplastic) as well as in the blood of 22 of them (8 tuberculous and 14 neoplastic), comparing these levels with those of a control group in 99 normal individuals. The concentration of neopterin was determined by radioimmunologic assay. This showed a significant increase (p < 0.001) of neopterin levels in the tuberculous pleural fluid, compared to the neoplastic group (42 ± 23/17 ± nmol/L).In the blood, values were nearly identical to the pleural fluid (41.3 ±25/15.8 ± 6.9 nmol/L), although with significant differences between them and in relation to the control group (p < 0.001), which had a normal serum value (5.11 ± 1.92 nmol/L).We emphasize the influence of the neopterin levels in the pleural fluid on the diagnosis of causes of pleurisy and its importance as a marker of immunologic cellular activity.

Ectopic thyroid in the anterior mediastinum

Ectopic thyroid is a rare condition, and its location in the anterior mediastinum is even rarer, there having been only 5 reported cases in the past 30 years. Here, we describe 2 clinical cases and present a review of the literature regarding the etiology, embryology and clinical manifestations of ectopic thyroid.

Ventilation and perfusion display in a single image

A new method of ventilation and perfusion display onto a single image is presented. From the data on regions of interest of the lungs, three-dimensional histograms are created, containing as parameters X and Y for the position of the pixels, Z for the perfusion and colour for local ventilation. The perfusion value is supplied by sets of curves having Z proportional to the local perfusion count rate. Ventilation modulates colour. Four perspective views of the histogram are simultaneously displayed to allow visualization of the entire organ. Information about the normal ranges for both ventilation and perfusion is also provided in the histograms.

Validação do estudo da permeabilidade da barreira alvéolocapilar com 133Xe

ABSTRACT A preliminary review of physical concepts related with the solubility of inert gases in tissues and with the permeability of inert gases through the alveolar-capillary membrane in the context of this paper, is firstly presented. The solubility laws of gases in liquids and tissues, the concept of partial pressure of a gas in a tissue, the solubility and partition coefficients, the equilibrium of gases in the lungs, the gas diffusion through the capillary walls, etc., are brevely dealed with in this part of the work. The importance of a physiological method to study the alveolar-capillary barrier permeability with local information is emphasized. In the present paper the physiological and practical reasons which favour gas utilization, and particularly 133 Xe, instead of aerosols, to evaluate the alveolar-capillary barrier permeability are considered. A method to evaluate the disappearance times of 133 Xe activity and obtain parametric images is described. The advantages to display 133 Xe permeability images concomitantly with the ventilation and perfusion images and its interest is shown with some examples. General aspects of the use of 99m Tc-DTPA aerosols and CO classical spirometry with infra red analysis to study the alveolar-capiillary barrier permeability are considered. In a group of pacients, parametric images of the alveolar-capillary barrier permeability were obtained both with 133 Xe, using our technique and with the usual method of Nuclear Medicine using 99m Tc-DTPA aerosols. The disapearence times obtained by the two techniques are in general terms correlated, however, a considerably higher specificity is obseved in the case of 133 Xe. In a second group of patients the global mean disapearence times of 133 Xe, in the region of interest of the lungs, were compared with the CO diffusion times obtained with a convencional CO test. The agreement between the tests is very good in what concerns the ability to distinguish normal from abnormal, however, the local information offered by the 133 Xe technique was felt to be an information of great value in many situations. The results obtained, up to now, with 133 Xe indicate that the information provided may be a further step in the study of the alveolar-capillary barrier compromises, even in the early stages.