[Effects of glucocorticoids on tuberculous pleural effusion: experiment with rats].

OBJECTIVE: To explore the effects of systemic glucocorticoid treatment on tuberculous pleural effusion. METHODS: Ninety Wistar rats were intrapleurally injected with 0.03 mg of standard human Mycobacterium tuberculosis to establish models of tuberculous pleural effusions and then were randomly divided into 2 equal groups both without anti-tuberculosis treatment: glucocorticoids group (GG) undergoing intramuscular injection of 0.3 mg triamcinolone acetonide in the right thigh 24 h after intrapleural injection, and control group (CG) received nothing as control. 8, 24, 32, and 48 hours, and 3, 5, 7, 10, and 15 days after intramuscular injection 5 rats from each group were killed. The thorax was opened, the amount of pleural effusion (PE) was recorded, and the pleural cavity, histopathology of pleura and lung parenchyma were examined. The white blood cell (WBC) count and differential leukocyte count, and levels of total protein (TP), glucose (GLU), and lactic dehydrogenase (LDH) in the PE were determined. Bioassays were used to detect the PE levels of soluble intercellular adhesion molecule-1 (sICAM-1), transforming growth factor beta1 (TGF-beta1), and interferon gamma (IFN-gamma). RESULTS: The PE volumes of GG 8 - 48 h after the intramuscular injection were significantly lower than those of CG (P < 0.05, P < 0.01), and PE completely disappeared on day 3. The WBC in PE 24 - 48 h after and the percentages of neutrophils 8 - 48 h after the intramuscular injection of GG were all significant lower than those of CG (all P < 0.01). The TP levels 32 and 48 h after the intramuscular injection of GG were both significantly higher than those of CG (both P < 0.01). The LDH level of GG within 24 h after the intramuscular injection was significantly lower than that of CG (P < 0.01). Both the sICAM-1 and TGF-beta1 levels of GG were higher 8 h after the intramuscular injection, but lower 48 h after the intramuscular injection than those of CG (both P < 0.01). The IFN-gamma levels 8 - 48 h after the intramuscular injection of GG were all higher than those of CC (all P < 0.01). The IFN-gamma/TGF-beta1 ratios at different time points of GG were all higher than those of CG, and there were significant differences in those 8 - 48 h after the intramuscular injection between these 2 groups (all P < 0.01). Pathologically, the mean thickness of pleura in GG was significantly less than that in CG. Congestion and edema in subpleural and pulmonary interstitium were less in GG than in CG. CONCLUSION: Early use of glucocorticoids helps reduce the inflammatory response in pleural cavity in tuberculous pleurisy accelerate the absorption of pleural effusion and decrease the thickness of pleura.

[Analysis on the current situation of Mycobacteria other than tuberculosis during 1994-2003 in the old city area of Guangzhou].

OBJECTIVE: To analyze the current situation and trend of Mycobacteria other than tuberculosis (MOTT) in the old city area of Guangzhou and to provide information for diagnosis, treatment and policy on tuberculosis (TB) control in the city. METHODS: Relevant data regarding Mycobacteria culture, species identification and drug-resistance from out-patients under suspicion of having pulmonary tuberculosis seen at our TB and Pulmonary Tumor Control Institute, was analyzed retrospectively during 1994-2003. RESULTS: A total number of 12,634 strains of Mycobacteria were isolated and 794 strains were identified as MOTT which accounted for 6.28% of the isolated strains during the ten years. The annual isolation rates of MOTT were between 3.51% and 10.06%. When compared with 1994, the rates of isolation on MOTT had increased 73.15% in 2003, i.e. from 5.81% in 1994 to 10.06% in 2003. 512 strains were not susceptible at least to rifampin and isoniazid out of 613 MOTT strains tested for drug susceptibility to isoniazid, rifampin, streptomycin sulfate and ethambutol. The average rate of multi-drugs resistance of these strains was 83.5%, and the annual rates were between 71.4% and 93.9%. Based on the results of species identification on 136 strains of MOTT in 2003, most of them belonged to pathogenic/opportunistic species of Mycobacteria. All together, 30 strains of M. abscessus, 26 of M. intracellulare, 17 of M. smegmatis, 14 of M. scrofulaceum, 11 of M. avium, 5 of M. kansasii and M. chelonae and M. fortuitum respectively, 4 of M. nonchromogenicum, 2 of M. triviale and 1 of M. aurum were identified. People at 45 years of age or older, with 55-65 the most, were more susceptible to MOTT than other age groups. Sex ratio was 3.36 to 1. CONCLUSION: Based on information from the Third National Tuberculosis Epidemiology Survey in 1990 and the Fourth one in 2000, the current situation and trend of MOTT were nearly the same in the old city area of Guangzhou during 1994-2003. However, the rising tendency of rate of isolation, mainly consisted of opportunistic pathogens and the surprisingly high rate of multi-drugs resistance to MOTT all call for special attention. Studies regarding the epidemiology of MOTT should be posed and implemented in the National TB Control Program.

[Study on species identification of Mycobacteria by gas chromatography analysis of whole-cell fatty acid].

OBJECTIVE: To evaluate the accuracy and applicability of species identification method of Mycobacteria by applying gas chromatography analysis of whole-cell fatty acid. METHODS: Species identification of 14 reference strains and 727 clinical isolates of Mycobacteria were performed by using MIDI Sherlock Microbial Identification System (MIS)4.0 based on gas chromatography analysis of whole-cell fatty acid, and the results were compared with those of conventional species identification method. RESULTS: (1) By using the conventional method, all 14 reference strains were identified correctly. Except for Mycobacterium.vaccae, the result obtained by MIS were identical to that of conventional method. (2) Among 625 clinical isolates identified as Mycobacterium tuberculosis (MTB) and Mycobacterium bovis, 45 strains were mistakenly identified as Nontuberculous Mycobacteria (NTM) by MIS. Its accuracy was 93%. For 102 NTM strains, results of group identification showed no difference between the two methods. However, 7 results of species identification were not consistent, the accuracy being 93%. (3) MIS mainly mistook MTB for Mycobacterium gastri, Mycobacterium trivial and Mycobacterium smegmatis, and Mycobacterium scrofulaceum for Mycobacterium gordonae among NTM. CONCLUSIONS: The results of species identification of Mycobacteria by applying gas chromatography analysis of whole-cell fatty acid are in accordance with those of conventional method for the majority of the strains, and MIS can identify Mycobacteria to species level by a single experiment. It can be considered as a good method for species identification of Mycobacteria in terms of its accuracy and applicability.

[A study on the model of tuberculous pleurisy and intrapleural inflammatory and immunological responses in rats].

OBJECTIVE: To develop a rat model of tuberculous pleurisy and to explore the mechanism of intrapleural inflammatory and immunological responses. METHODS: Fifty Wistar rats were injected intrapleurally with 0.03 mg of standard human mycobacterium tuberculous bacilli H37Rv each. The rats were killed in group on days 1, 2, 3, 5, 7, 10, 15, 20, 30 and 60 after the day of intrapleural injection. The thorax was opened and the amount of pleural effusion was recorded, and histopathology of pleural tissues and lung tissues were observed. The white blood cell (WBC) count and differentials, levels of total protein (TP), glucose (GLU) and lactic dehydrogenase (LDH) of pleural effusions were determined. Pleural fluid was analyzed for the levels of soluble intercellular adhesion molecule-1 (sICAM-1), transforming growth factor beta1 (TGF-beta1) and interferon gamma (IFN-gamma) by using appropriate bioassays. Ten rats were intrapleurally received 2 ml of normal saline and another 10 rats received 2 ml of undiluted PPD solution each as control. RESULTS: Bilateral pleural effusions appeared within 15 days in all rats intrapleurally received tuberculous bacilli. The peak amount of pleural fluid was on day 5 (6.7 +/- 0.5 ml). The neutrophils were the predominant cells for the first 24 hours, and then were followed by lymphocytes. In the pleural fluid, total protein concentration was between 51-55 g/L. The levels of glucose and LDH were 5.2 mmol/L and 18.1 micromol.s(-1).L(-1) on day 1 and changed to 2.8 mmol/L and 28.9 micromol.s(-1).L(-1) on day 15 respectively. The biochemistry parameters were in accordance with characteristics of tuberculous pleurisy. The sICAM-1 level increased early (21.9 ng/ml on day 1) and peaked on day 3 (38.0 ng/ml), then decreased over time (4.4 ng/ml on day 15). The level of IFN-gamma was 41.2 pg/ml on day 1 and increased and maintained at high levels over time. TGF-beta1 levels increased and peaked on day 7 (47.2 ng/ml), and then on day 15 decreased to a level lower than that of day 1. The ratio of IFN-gamma/TGF-beta1 increased from 1.32 on day 1 to 5.69 on day 15. Correlation analysis showed that sICAM-1 and IFN-gamma were closely related with WBC count and its differentials, as well as with LDH levels. Histopathological study revealed early pleural inflammation and late caseation. CONCLUSIONS: Wistar rats can be used as an experimental model for tuberculous pleurisy. Tuberculous inflammatory and immunological responses in acute tuberculous pleurisy is enhanced rather than suppressed.