BACKGROUND/AIMS: The clinical outcomes of some patients with pleural infection may be favorable with medical treatment alone, but in others, the disease progresses and requires additional surgical treatment. However, little is known about the factors affecting this difference. The aim of this study was to investigate the factors predictive of failure of medical treatment in patients with pleural infection. METHODS: A cohort of 127 consecutive patients who were admitted to the hospital with pleural infection was studied. Clinical manifestations and laboratory findings in patients in whom medical treatment succeeded or failed were reviewed. RESULTS: In univariate analysis, the significant factors associated with medical treatment outcome were age, smoking history, duration of chief complaint, serum albumin level, and pleural fluid glucose and lactate dehydrogenase levels (p < 0.05). Multivariate logistic regression analysis identified age and duration of chief complaint as independent predictive factors for failure of medical treatment, with odds ratios of 0.871 (p = 0.013) and 0.797 (p = 0.026), respectively. Receiver operating characteristic curve analysis determined cutoff values of 50.5 years for age and 4.5 days for duration of chief complaint. CONCLUSIONS: We demonstrated that a younger age < 50.5 years and shorter duration of chief complaint < 4.5 days were independent predictive factors for the failure of medical treatment in patients with pleural infection. This suggests their role as evaluative criteria in setting indications for the optimal treatment in patients with pleural infection. A larger, prospective study is required to confirm these findings.
Adult ; Aged ; Anti-Bacterial Agents/therapeutic use ; Cohort Studies ; Drainage ; Empyema, Pleural/metabolism/*therapy ; Female ; Glucose/metabolism ; Humans ; L-Lactate Dehydrogenase/metabolism ; Male ; Pleural Effusion/metabolism/*therapy ; Serum Albumin/metabolism ; Thoracic Surgery, Video-Assisted ; Treatment Failure

BACKGROUNDThe discovery of water channel aquaporins (AQPs) has greatly expanded the understanding of the regulation of the water permeability of biological membranes. Aquaporin-1 (AQP1) may be involved in fluid transport in numerous pathological conditions. The objective of the present study was to examine whether AQP1 is present in cultured rat pleural mesothelial cells (PMCs) and to investigate the specific inhibitory effect of RNA interference (RNAi) on AQP1 expression in PMCs, which may provide a new method for the further studies on the relation between expression of AQP1 in PMCs and pleural fluid removal in vivo.

METHODSPMCs were isolated and cultured from rat pleura. The expression of AQP1 in PMCs was confirmed by immunocytochemical staining and reverse transcriptase-polymerase chain reaction (RT-PCR). Two eukaryotic expression plasmid vectors of short hairpin RNA (shRNA) specific for the AQP1 gene of rat sapien were designed and constructed. The recombinant plasmid vectors were transfected into cultured rat PMCs by cation liposomes. Flow cytometry was used to screen the most effective shRNA at 48 hours after transfection. The expressions of AQP1 mRNA and protein were detected by RT-PCR and Western blotting method at 48 hours after transfection.

RESULTSRT-PCR and immunostaining revealed that AQP1 mRNA and protein were present in cultured rat PMCs. Two effective eukaryotic expression plasmid vectors of shRNA specific for the AQP1 gene were constructed successfully. The levels of the expression of AQP1 were inhibited by 83.45%, 90.93%, respectively, at mRNA level and 41.24%, 67.60%, respectively at protein level by two recombinant plasmids at 48 hours after transfection. The expression of AQP1 in PMCs transfected with plasmid was significantly lower than that of the cells transfected with the control plasmid HK and that of the untransfected cells (P < 0.01). There was no significant difference in AQP1 expression between the control group and the group transfected with AQP1 nonspecific shRNAs (P < 0.05).

CONCLUSIONSThe expression of AQP1 was present in rat PMCs. The application of shRNA-AQP1 could markedly inhibit the expression of AQP1 in cultured rat PMCs. The use of RNAi is a promising tool for future research into the mechanisms of pleural fluid in vivo.

Animals ; Aquaporin 1 ; antagonists & inhibitors ; genetics ; Cells, Cultured ; Epithelial Cells ; metabolism ; Flow Cytometry ; Male ; Microscopy, Fluorescence ; Pleura ; cytology ; metabolism ; Pleural Effusion ; therapy ; RNA Interference ; RNA, Small Interfering ; genetics ; Rats