Detecting drug resistant genetic mutation among pneumoconiosis patients complicated with tuberculosis in Mycobacterium tuberculosis L-forms application of PCR-SSCP technique in Huainan mining district

Objective： To study the relationship between drug resistant genetic mutation and drug resistance in Mycobacterium tuberculosis L-form, discuss the internal relationship between drug resistances and drug-resistant related genes and explore the value of PCR- SSCP to clinical application. Methods： A total of 52 clinically isolated strains of tuberculosis L-form were collected among 97 pneumoconiosis patients complicated with tuberculosis. The gene mutations of katG, rpoB and rpsL were detected by PCR-SSCP, and the results were compared with those analyzed by traditional antimicrobial susceptibility test（AST）. Results： The gene muta- tion rates of katG, rpoB and rpsL by PCR-SSCP were respectively 57.70% （30/52）, 65.38% （32/52） and 40.38% （21/52）. The rate of reversion was 78.85%（41/52） and the result of drag-resistant genes was invariable. The results of AST showed that there were 40 （76.92%） multi-drug resistant strains in 52 clinically isolated strains. The number for three-drug resistant strain was 21 （40.38%） and that of two-drug resistant was 19（36.54%）, but only 12（23.08%） strains were one drug resistant. The rate of total drug-resistance was 100%, but there were 15 strains of allied mutation of three genes, 16 of two mutations and 6 of only one by PCR-SSCP. The coincidences were respectively 71.43%, 84.12% and 50.00%. Then there was no significant difference between the allied mutations of multi-drug resistant gene and the mutations of only one drug resistant gene （P 〉 0.05）. Conclusion： PCR-SSCP technique has a higher sensibility and specificity to detect the genes of katG, rpoB and rpsL in tuberculosis L-form among pneumoconiosis complicated with tuberculosis,and the detecting rate of two drug resistant strains and three drug resistant strains was higher. The combined application of PCR-SSCP and AST has advantages at earlier diagnosis and guidance of clinical medications.

Research on fault mode and diagnosis of methane sensor

To improve the reliability of coal mine safety monitoring systems we have analyzed the characteristics of a methane sensor, an important component of the monitoring system of production safety in a coal mine and studied the main type and mode of faults when the sensor was used on-line. We introduced a new method based on artificial neural network to detect faults of methane sensors. In addition, using the output information of a single methane sensor, we established a sensor output model of a dynamic non-linear neural network for on-line fault detection. Finally, the fault of the heating wire of the sensor was simulated, indicating that, when the methane sensor had a fault, the predicted output of the neural network clearly deviated from the actual output, exceeding the pre-set threshold and showing that a fault had occurred in the methane sensor. The result shows that the model has good convergence and stability, and is quite capable of meeting the requirements for on-line fault detection of methane sensors.

The survey of Cryptosporidium infection among young children in kindergartens in Anhui province

Objective：To study the Cryptosporidium infection among young children in Anhui province, and to explore the best way to diagnose the disease. Methods： Stool specimens of 1 204 children were collected; oocysts of Cryptosporidium were identified with auramine O- modified staining, acid-fast staining, safranine T and methylene blue staining, and auramine O-modified acid-fast staining. Results： The detectable rate of Cryptosporidium in four stainings were respectively 2.46%, 1.50%, 1.98% and 3.46%, and there was a higher significant difference in the rate between auramine O-modified acid-fast staining and the others（P 〈 0.005）. The detectable rate was significantly lower in urban children（2.14%, 15/684） than in rural ones（5,19%, 27/520）. Boys and girls had similar detectable rate （1.99%, 24/1 204 vs. 1.50%, 18/1 204）. Cryptosporidium infection was usually subclinical, and its major clinical features included benign diarrhea, mild abdominal pain and nausea. Conclusion：Cryptosporidium infection was relatively common in kindergartens and a higher infection rate was found in rural children. As the majority of the Cryptosporidium infections were subclinical, diagnosis is important although difficult.