Influence of antiinflammatory drugs (methylprednisolone and diclofenac sodium) on experimental pleurodesis induced by silver nitrate or talc.

STUDY OBJECTIVE: To determine whether the administration of antiinflammatory drugs interferes with experimental pleurodesis induced by silver nitrate or talc. STUDY DESIGN: Two groups of 30 white New Zealand rabbits were scheduled to receive an intrapleural injection of 0.5% silver nitrate or 400 mg/kg of talc. Each group was further classified into three subgroups (10 animals each), which received the following: (subgroup 1) the sclerosing agent only, (subgroup 2) the sclerosing agent plus 1 mg/kg of methylprednisolone, and (subgroup 3) the sclerosing agent plus 1.1 mg/kg of diclofenac sodium. The antiinflammatory agents were administered IM 24 h before the sclerosing agent and daily during the first week, followed by once-weekly injections until death at 28 days. At this time, the pleural cavity was macroscopically evaluated, and samples of pleura and lungs were collected for further microscopic examination. MEASUREMENTS AND RESULTS: The degree of pleural adhesions was higher after silver nitrate administration (p = 0.019). No reduction in the adhesions was observed after administering antiinflammatory drugs to this group (p > 0.05). Conversely, the adhesion score was significantly reduced after administration of both prednisolone (p = 0.028) and diclofenac (p = 0.032) to the animals that received talc. Administration of the antiinflammatory agents did not influence microscopic pleural or lung changes induced by silver nitrate or talc. CONCLUSION: These results show that the sustained systemic administration of antiinflammatory agents (steroidal or nonsteroidal) reduces the degree of pleural adhesions in animals with talc-induced pleurodesis but does not affect silver nitrate-induced pleurodesis. Extrapolation of these results to humans suggests that the use of antiinflammatory drugs should be avoided in patients with talc-induced pleurodesis and that appropriate clinical studies with silver nitrate should be conducted in patients chronically treated with these antiinflammatory agents.

Linfoma primário de cavidade pleural em paciente imunocompetente / Primary effusion lymphoma in an immunocompetent patient

O linfoma primário de cavidade é um tipo raro de linfoma não-Hodgkin que acomete principalmente pacientes imunocomprometidos e, mais raramente, pacientes imunocompetentes. Neste relato de caso são apresentados os achados clínicos e laboratoriais de um paciente imunocompetente com derrame pleural diagnosticado como linfoma primário de cavidade pleural.

Primary effusion lymphoma is an unusual non-Hodgkin's lymphoma rarely seen in immunocompetent patients. Herein, we present clinical and biochemical data obtained from an immunocompetent patient diagnosed with primary effusion lymphoma.

Ultrastructural acute features of active remodeling after chemical pleurodesis induced by silver nitrate or talc.

This study evaluated submicroscopic features of active pleural remodeling associated with chemical pleurodesis. Twenty seven rabbits received intrapleural injection of 0.5% silver nitrate (SN; N = 9) or 400 mg/kg talc slurry (N = 9) in 2 ml of saline solution; control rabbits (N = 9) received 2 ml of saline alone. The rabbits were sacrificed 15 minutes, 24 hours, or 7 days postinjection, and specimens of visceral pleura were obtained, fixed, and photographed for submicroscopic analysis. After 15 minutes of talc or SN exposure, prominent injury to the mesothelial cells and mesothelial cell-mesothelial basement membrane (MC-MBM) union was visible. There was focal remesothelialization of the denuded area through mesothelial cell migration, proliferation, and differentiation. After 24 hours, early wound healing, characterized by a superficial exudate, was evident where myofibroblasts had proliferated through a gap in the MC-MBM. After 7 days, proliferation of highly active myofibroblasts was observed; these cells produced abundant extracellular matrix components in a more organized distribution paralleling the surface. This third stage of remodeling was more evident with SN than talc-induced chemical pleurodesis. Our results suggest that ideal chemical pleurodesis results from injury to the MC-MBM union and abnormal wound healing, involving three essential steps: remesothelialization, fibroblastic proliferation, and extracellular matrix accumulation and remodeling.

Pleurodesis induced by intrapleural injection of silver nitrate or talc in rabbits: can it be used in humans?

OBJECTIVE: To evaluate the pleuropulmonary alterations caused by intrapleural injection of silver nitrate or talc in an experimental model, in order to consider its use in human beings. METHOD: 112 rabbits were randomly selected to receive intrapleural 0.5 percent silver nitrate or 400 mg/kg talc slurry in 2 ml saline. Eight rabbits of each group were sacrificed after 1, 2, 4, 6, 8, 10, or 12 months. Regarding the pleural cavity, the degree of macroscopic pleurodesis (adherences) and microscopic alterations, represented by inflammation and pleural fibrosis, were analyzed. The parenchyma was evaluated regarding the degree of alveolar collapse, intra-alveolar septum edema, and cellularity, on a 0 to 4 scale. RESULTS: Intrapleural injection of silver nitrate produced earlier and more intense pleurodesis than talc slurry injection. The parenchymal damage was more evident with silver nitrate, considered as moderate, and limited to the first evaluation (after one month). From the second month on and throughout the entire one-year follow-up, the parenchymal damage was similar with both substances, only the pleural adherences were more intense with silver nitrate. CONCLUSIONS: Intrapleural silver nitrate produces better and longer-lasting than intrapleural talc injection. The parenchymal alterations, although discreet, are more pronounced when silver nitrate is used, but minimal after two months, and similar to those produced by talc injection during the entire one-year observation period. These effects on the pulmonary parenchyma do not contraindicate the use in humans. Thus, the use of intrapleural silver nitrate to produce fast and effective pleurodesis can be considered in patients in which pleural cavity symphysis is desired.

Lung damage in experimental pleurodesis induced by silver nitrate or talc: 1-year follow-up.

STUDY OBJECTIVE: To compare the lung damage caused by intrapleural silver nitrate (SN) with that caused by talc over a 12-month period. DESIGN: One hundred forty rabbits received an intrapleural injection of 0.5% SN or 400 mg/kg talc slurry in 2 mL saline solution. Groups of 10 rabbits were killed after 1, 2, 4, 6, 8, 10, or 12 months. The macroscopic pleurodesis, microscopic lung changes (ie, collapse, hemorrhage, and edema), and cellular infiltrates (number and proportion of cells) were graded on a scale of 0 to 4. RESULTS: The mean (+/- SEM) adhesion score after SN injection (3.3 +/- 0.1) was higher (p < 0.001) than that after talc injection (2.3 +/- 0.1). The mean alveolar collapse score was greater (p < 0.001) 1 month after SN injection (2.2 +/- 0.3) than after talc injection (0.2 +/- 0.1) and was similar from the second month on. The degree of parenchymal hemorrhage, by alveolar collapse score, (SN injection, 0.2 +/- 0.1; talc injection, 0.2 +/- 0.0) and edema (SN injection, 0.4 +/- 0.1; talc injection, 0.3 +/- 0.1) was minimal in both groups (p > 0.05). One month after the injection, the total number of inflammatory cells was greater (p < 0.001) in rabbits that had received SN injections (2.7 +/- 0.3) than in those that had received talc injections (1.2 +/- 0.1). From the second month on, cellularity decreased and became similar in both groups. The cellular profile was different, with a predominantly neutrophilic reaction after talc injection and a predominantly eosinophilic reaction after SN injection. CONCLUSIONS: Rabbits injected with intrapleural 0.5% SN had significantly higher scores for adhesions than did those that had received talc injections, with mild and reversible alveolar collapse and an eosinophilic responses, conditions showing a clear tendency to normalize with time.

Effectiveness of silver nitrate compared to talc slurry as pleural sclerosing agent in rabbits: influence of concomitant intrapleural lidocaine

The ideal agent for producing pleurodesis has not been identified. Talc, the most commonly used, poses several problems. Another possibility is silver nitrate, which was widely used in the past. PURPOSE: To determine the influence of the intrapleural instillation of lidocaine in producing a pleurodesis with silver nitrate, to define the effect of lidocaine in the maturation of the collagen fibers, and to confirm that the pleurodesis after silver nitrate is stronger than after talc. METHODS: We studied three groups of 8 rabbits. Two groups received 0.5 percent silver nitrate; in one we had previously injected 0.5 ml of 2 percent lidocaine. The third group received 400 mg/kg talc (2 ml). The animals were sacrificed 28 days after the injection, and the pleural spaces were assessed grossly for evidence of pleurodesis and microscopically for evidence of inflammation and fibrosis. The total amount of pleural collagen and the distribution of thick and thin collagen fibers were quantified. Collagen was identified using picrosirius red stain. RESULTS: In the two groups that received silver nitrate (without lidocaine: 3.5 + 03 and with lidocaine: 3.2 + 0.3), the macroscopic pleurodesis (scale 0 3/4 4) was significantly (p = 0.001) better than that resulting from talc (1.6 + 0.2). The mean degree of pleural fibrosis induced by silver nitrate (3.5 + 0.2) was significantly (p = 0.004) higher than that induced by talc (1.9 + 0.1). The previous instillation of lidocaine resulted in a tendency for decreased amounts of fibrosis (3.1 + 0.4). The mean amount (10(3)mm2) of pleural collagen was significantly (p = 0.009) greater in the rabbits that received silver nitrate (116.9 + 22.7) than in those that received talc (10.7 + 3.4). The injection of lidocaine slightly reduced the collagen (80.1 + 30.3). The distribution of collagen fibers did not differ among the groups. CONCLUSION: This rabbit model clearly confirms that intrapleural silver nitrate is more effective than talc for producing pleurodesis. The previous intrapleural instillation of lidocaine results in a decreasing trend in the amount of collagen, but does not change the effectiveness of the pleural fusion or modify the process of collagen maturation.