Repeatability of pleural adenosine deaminase measurements in diagnostic evaluation of pleural effusions.

BACKGROUND: A follow-up thoracentesis is proposed in suspected atypical tuberculosis cases. The study aimed to define the variability of pleural ADA values across repeated thoracenteses in different types of pleural effusions (PEs) and to evaluate whether ADA variance, in regard to the cutoff value of 40 U/L, affected final diagnosis. METHODS: A total of 131 patients with PEs of various etiologies underwent three repeated thoracenteses. ADA values were subsequently estimated. RESULTS: 82% and 55% of patients had greater than 10% and 20% deviation from the highest ADA value, respectively. From those patients who had a variance of 20%, 36% had only increasing ADA values, while 19% had only decreasing values. Considering the cutoff value of 40 U/L, only in two cases, ADA decreased below this threshold, which concerned a man with tuberculous pleurisy and a woman with lymphoma both in the course of treatment. Furthermore, only in two cases with rising values, ADA finally exceeded the cutoff limit, which concerned a man with rheumatoid pleurisy and a man with tuberculous pleurisy. Surprisingly, malignant PEs (MPEs) showed a higher percentage of increasing values compared to all other exudates that did not, however, exceed the threshold. CONCLUSION: The determination of pleural ADA levels is a reproducible method for rapid tuberculosis diagnosis. The detected measurement deviations do not appear to affect final diagnosis. In specific situations, repeated ADA measurements may be valuable in directing further diagnostic evaluation. More investigation is needed to elucidate the possible prognostic significance of the increasing trend in ADA values in MPEs.

[Difficulties in classifying body cavity fluids into transudate/ exudate depending on the various diagnostic criteria]. / Trudnosci w klasyfikacji plynów z jam ciala na przesiek/wysiek na podstawie róznych kryteriów diagnostycznych.

Disease processes may impair the production and reabsorption of fluid from in the body cavities, which results in its excessive accumulation. AIM: The aim of the study was the evaluation of difficulties regarding the classification of fluids from the body cavities into transudate/exudate observing the following: Light's criteria, total fluid protein concentration, and total protein ratio (TP ratio) and lactate dehydrogenase ratio (LDH ratio). MATERIALS AND METHODS: Retrospective analysis was conducted on pleural (N=314), peritoneal (N=114) and pericardial (N=10) fluids, which were tested for the total protein concentration and LDH activity both in fluid and serum and calculated on TP ratio and LDH ratio. RESULTS: Based on the total protein concentration, 278 fluids from pleural cavity were classified as an exudate; 36 as a transudate. Applying the Light's criteria 240 fluids were classified as an exudate; the remaining 74 fluids were classified as a transudate. Based on TP and LDH ratios, 229 fluids from pleural cavity were classified as an exudate; 85 as a transudate. Depending on the total protein concentration, 35 fluids from the peritoneal cavity were classified as an exudate; 79 as a transudate. Applying the Light's criteria 54 fluids were classified as an exudate; the remaining 60 fluids were classified as a transudate. Based on TP and LDH ratios, 22 fluids from peritoneal cavity were classified as an exudate; 92 as a transudate. Analysis of pericardial fluids, depending on the total protein concentration classified 9 of them as an exudate and 1 as a transudate. The same results were obtained by applying Light's criteria. Based on TP and LDH ratios, 7 fluids from pericardial cavity were classified as an exudate; 3 - as a transudate. CONCLUSIONS: Applying the Light's criteria or the total protein concentration in differential diagnostics of fluids from the body cavities resulted in qualification more of them as an exudates as compared to the analysis of the same fluids depending on the TP and LDH ratios. It can be assumed that some of the transudative/exudative fluids were incorrectly classified. Performed analysis suggest that more adequate criteria of the classification of fluids from the body cavities into transudate/exudate are of great importance.

Predictive models for diagnosis of pleural effusions secondary to tuberculosis or cancer.

BACKGROUND AND OBJECTIVE: Tuberculosis (TB) and cancer are two of the main causes of pleural effusions which frequently share similar clinical features and pleural fluid profiles. This study aimed to identify diagnostic models based on clinical and laboratory variables to differentiate tuberculous from malignant pleural effusions. METHODS: A retrospective study of 403 patients (200 with TB; 203 with cancer) was undertaken. Univariate analysis was used to select the clinical variables relevant to the models composition. Variables beta coefficients were used to define a numerical score which presented a practical use. The performances of the most efficient models were tested in a sample of pleural exudates (64 new cases). RESULTS: Two models are proposed for the diagnosis of effusions associated with each disease. For TB: (i) adenosine deaminase (ADA), globulins and the absence of malignant cells in the pleural fluid; and (ii) ADA, globulins and fluid appearance. For cancer: (i) patient age, fluid appearance, macrophage percentage and presence of atypical cells in the pleural fluid; and (ii) as for (i) excluding atypical cells. Application of the models to the 64 pleural effusions showed accuracy higher than 85% for all models. CONCLUSIONS: The proposed models were effective in suggesting pleural tuberculosis or cancer.

Study of telomerase activity in pleural lavage fluid specimens in patients with non-small-cell lung cancer and its clinical significance.

OBJECTIVE: To detect telomerase activity in pleural lavage fluid specimens in patients with non-small-cell lung cancer (NSCLC) and to evaluate its clinical value. METHODS: From July 2005 to May 2007, 167 pleural lavage fluid specimens were obtained from 135 patients with NSCLC and 32 patients with benign lung tumour during operation. Telomeric repeated amplification protocol (TRAP)-enzyme-linked immunosorbent assay (ELISA) was performed to measure the telomerase activity in these specimens. Pleural lavage cytology (PLC) analysis of the pleural lavage fluid specimens was used for comparison. All the above specimens were examined within 3h. RESULTS: The positive rate of telomerase activity and PLC in pleural lavage fluid from patients with NSCLC was 25.2% (34/135) and 8.1% (11/135), respectively, with a significant difference (P<0.05). Telomerase activity was detected in all 11 specimens with positive cytological examination. Telomerase activity was negative in all 32 patients with benign lung tumour. There was a significant relationship between telomerase activity and pleural extension, T level, N level as well as the clinical TNM (tumour, node, metastasis) stage of lung cancer. A significant association was found between positive telomerase activity and overall survival rate, even stage I survival rate. Multivariate Cox regression analysis demonstrated that telomerase activity, as well as PLC and the TNM stage were independent predictors of prognosis. CONCLUSION: Telomerase activity is a useful adjunct for cytological method in the diagnosis of pleural micro-metastasis and was related to prognosis in a patient with NSCLC.

[Diagnostic characteristics of adenosine deaminase test in Byelorussian patients with tuberculous pleurisy].

The results of studying the diagnostic value of changes in the pleural fluid and serum activities of adenosine deaminase (ADA) and its isozymes are analyzed in Byelorussian patients with tuberculous pleurisy. There is an increased serum and pleural fluid ADA activity in the patients with tuberculous pleurisy caused mainly by a rise in ADA2 activity. The test determining the activity of ADA, and ADA2 in particular, has shown high sensitivity and specificity as compared with the results obtained in other countries. The diagnostic efficacy of determination of these indices in the serum is also high, but it is lower than that in the pleural fluid.

Pleural fluid ADA, IgA-ELISA and PCR sensitivities for the diagnosis of pleural tuberculosis.

The diagnosis of pleural tuberculosis (pTB) is difficult, and more sensitive and specific techniques are needed. In the period August 1998 to November 2002, we evaluated 132 patients with a pleural effusion submitted to a thoracentesis and pleural biopsy in a tertiary care hospital in Rio de Janeiro, Brazil. Three tests were performed and compared in the pleural fluid: ADA activity measurement, IgA-ELISA for two combined specific Mycobacterium tuberculosis antigens, and polymerase chain reaction (PCR) for detection of M. tuberculosis DNA. Ninety-five patients (72%) were given a final diagnosis of pTB. Overall histopathologic sensitivity was 77%. The sensitivities of pleural fluid culture and AFB smear were 42% and 1%, respectively. Twenty-one (22%) additional patients had a clinical diagnosis of pTB. Median follow-up time of all TB patients after the completion of antituberculous treatment was 13 months. Sensitivities of ADA, IgA-ELISA and PCR were 91%, 78% and 82%, while specificities were 93%, 96% and 85%, respectively. Only ADA sensitivity was significantly higher than the histopathologic examination (McNemar chi2 test; p = 0.002) and also significantly higher than ELISA (p = 0.049), but not higher than PCR (p = 0.143). We conclude that the routine use of ADA activity measurement in pleural fluid can obviate the need for a pleural biopsy in the initial diagnostic approach to pleural effusions, while IgA-ELISA and PCR techniques, potentially more specific tests, need further refinement to improve their accuracy.

Group IIA secretory PLA2 inhibition by ursolic acid: a potent anti-inflammatory molecule.

Ursolic acid (3beta-hydroxy-urs-12-en-28-oic acid) isolated from many medicinal plants has diverse pharmacologically important properties, including strong anti-inflammatory activity. However its interaction with pro-inflammatory PLA2 is not known. Ursolic acid inhibited secretory PLA2 (sPLA2) enzymes purified from Vipera russelli, Naja naja venom and human pleural fluid and synovial fluid. IC50 values determined for these enzymes ranged from 12 to 18 microM. Group II secretory PLA2 from both venoms & human inflammatory source were found to be sensitive to inhibition in comparison with group I cobra venom sPLA2. Variation in Ca2+ concentration from 2.5-15 mM did not alter the level of inhibition. Similarly sPLA2 inhibition by ursolic acid is independent of substrate concentration. Ursolic acid interacts with purified venom sPLA2 enzymes and enhances relative fluorescence intensity in a dose dependent manner. In the presence of ursolic acid apparent shift in the far UV-CD spectra of sPLA2 was observed, indicating a direct interaction with the enzyme and formation of enzyme-ursolic acid complex. This complex results in irreversible inhibition of sPLA2 as evident by dialysis study. Inhibition of sPLA2 induced mouse paw edema and indirect hemolytic activity confirmed its sPLA2 inhibitory activity in vivo and in situ respectively. These studies revealed that the strong anti-inflammatory activity of ursolic acid is by inhibiting sPLA2 enzymes.

Inhibition of secretory phospholipase A(2) enzyme by bilirubin: a new role as endogenous anti-inflammatory molecule.

Bilirubin is a powerful antioxidant that suppresses the inflammatory process. However its interaction with proinflammatory PLA(2) enzyme is not known. Inhibition of several secretory phospholipase A(2) (sPLA(2)) enzyme activities by bilirubin was studied using (14)C-oleate labeled Escherichia coli as substrate. Bilirubin inhibits purified sPLA(2) enzyme from Vipera russellii and Naja naja venom and partially purified sPLA(2) enzymes from human ascitic fluid, pleural fluid and normal serum in a dose dependent manner. IC(50) values calculated for these enzymes ranges from 1.75 to 10.5 microM. Inflammatory human sPLA(2) enzymes are more sensitive to inhibition by bilirubin than snake venom sPLA(2)s. Inhibition of sPLA(2) activity by bilirubin is independent of calcium concentration. Increasing substrate concentration (upto 180 nmol) did not relieve the inhibition of sPLA(2) by bilirubin and it is irreversible. Bilirubin quenched the relative fluorescence intensity of sPLA(2) in a dose dependent manner in the same concentration range at which in vitro sPLA(2) inhibition was observed. In the presence of bilirubin, apparent shift in the far UV-CD spectra of sPLA(2) was observed, indicating a direct interaction with the enzyme. Inhibition of sPLA(2) induced mouse paw edema by bilirubin confirms its sPLA(2) inhibitory activity in vivo also. These findings indicate that inhibition of sPLA(2) by bilirubin is mediated by direct interaction with the enzyme and bilirubin may act as an endogenous regulator of sPLA(2) enzyme activity.