ABSTRACT
Pleural tuberculosis [TB] is a diagnostic challenge because of its nonspecific clinical presentation and paucibacillary nature. The inefficiency of conventional laboratory methods and the reliance on pleural biopsy have motivated the evaluation of alternative diagnostic strategies. In this study, our goal was to improve the diagnosis of tuberculous pleural effusion and to determine the most sensitive, specific, and rapid diagnostic methods. We used PCR to detect DNA [IS 6110] specific for M tuberculosis complex and IFN-gamma quantitation on pleural fluid samples and compared them to the results of immunnocytopathology staining and conventional bacteriological methods [Ziehl Neelsen stain and culture using the LJ medium]. The study population included 50 patients presented with pleural effusion at Alexandria Main University Hospital and El Maamora Chest Hospital, between June 2004 to December 2004. In addition 5 cases of malignant pleural effusion were received from Damnhour oncology center - Behira, in the period from January 2004 to December 2004. According to the clinical diagnosis, the patients were distributed into 3 groups; group I; 14 patients with confirmed old tuberculosis patients group II ; 8 patients with Probable pleural tuberculosis and group III; 33 patients with Pleural effusion due to an etiology different from tuberculosis. For each specimen of pleural fluid; Immunocytochemical staining, Ziehl- Neelsen staining, culture on Lowenstein Jensen medium, measurement of IFN-gamma level, and PCR for detection of Mycbacterium tuberculosis DNA [IS 6110] were done. No samples were positive by Ziehl-Neelsen staining or by culture for M.tuberculosis. Only one case was positive for pleural tuberculosis by PCR. IFN-gamma values were significantly higher in the pleural fluid of patients with confirmed tuberculosis than in those with probable pleural tuberculosis. Ten out of 14 patient with confirmed tuberculosis. were reactive to IFN-gamma by ELISA [mean value = 276.2 picogram/ml], while only one case out of 8 cases with probable pleural tuberculosis was reactive [mean value = 2.5 picogram/ml]. As regards the third group with etiology different from tuberculosis, all the cases were not reactive by ELISA for IFN-gamma. PCR, and measurement of IFN-g levels provide the basis for the rapid and efficient diagnosis of pleural TB in different clinical settings
ABSTRACT
Helicobacter pylori [H. pylori] is recognized as the major cause of gastritis and peptic ulcer disease and has been classified as a carcinogen class I. Various tests have been developed to diagnose the infection, but all have limitations. H.pylori can be detected by non-invasive and invasive methods, the latter requiring endoscopy. Noninvasive testing for H.pylori is widely available and has been considered as an initial management strategy for uninvestigated dyspepsia. The aim of the present study was the evaluation of the different techniques used for diagnosis of the organism and to compare these techniques to the traditional ones. The present study was carried out on 40 patients suffering from dyspepsia. From these patients gastric biopsy specimens were taken for detection of H.pylori infection by the conventional methods [H and E staining, rapid urease test "RUT", and culture] and the PCR assay. In addition, stool samples were taken for the detection of H.pylori antigen and DNA by ELISA and PCR techniques respectively, saliva samples for PCR and blood samples for detection of H.pylori antibodies IgG were also taken. A case was considered positive for H.pylori infection if the organism was isolated by the culture or at least two of the conventional methods were positive. H.pylori infection was detected in 30 cases [75%]. H.pylori stool assay [HpSA] gave the highest rate of detection [70%], followed by serum antibody detection [50%]. The lowest rate of detection of H.pylori infection was by PCR assay in the stool and the saliva, which detected only 52.5% and 25% of cases respectively. H.pylori in the stool assay [HpSA] could be used as a routine diagnostic tool for H.pylori infection. It seems to overcome some limitations of the conventional invasive techniques. It has the potential advantages of being simple to perform, relatively cheap, and samples can be submitted directly from primary care