4株利奈唑胺不敏感粪肠球菌的23S rRNA基因突变分析

目的研究临床分离的4株利奈唑胺不敏感粪肠球菌的耐药机制。方法采用Vitek 2 Compact全自动微生物分析系统对临床分离的4株粪肠球菌进行鉴定和体外药物敏感性试验,利奈唑胺的最低抑菌浓度(MIC)采用E-test法进行复核。采用聚合酶链反应(PCR)扩增其氯霉素-氟甲砜霉素耐药(cfr)基因、23S r RNA V区和基因组23S r RNA 4个拷贝基因,经测序确定突变情况。结果 4株利奈唑胺不敏感粪肠球菌均未扩增出cfr基因,23S r RNA V区扩增片段连接T载体随机挑选6克隆测序,未发现利奈唑胺耐药最常见的G2576U突变。进一步分别扩增23S r RNA 4个拷贝基因并测序,仅1株菌存在1拷贝G2576U突变,4株菌均存在U2826C突变,另外还分别存在G2389A、U2363C和A2881G突变。U2826C位于23S r RNA可变区边缘,进一步扩增同期临床分离的利奈唑胺敏感粪肠球菌,测序结果显示均存在U2826C突变。结论临床分离的4株利奈唑胺不敏感粪肠球菌的23S r RNA存在散发突变,是其耐药的主要分子机制。

Effect of integrated traditional Chinese and Western medicine on SARS:A review of clinical evidence

AIM: To assess the possible effect of integrated traditional Chinese and Western medicine on severe acute respiratory syndromes.METHODS: The current available randomized controlled trials of integrated tradilJonal Chinese and Western medicine on SARS were identified through systematically searching literature in any languages or any types of publications.Additional studies of gray literature were also collected.The quality of studies was evaluated by two investigators independently based largely on the quality criteria specified CONSORT. Statistical analysis of the results was performed using RevMan 4.2.0 software developed by the Cochrane Collaboration.RESULTS: Six studies (n = 366) fulfilling the inclusion criteria were found, of which the quality of one study was graded as B, the remaining five were graded as C. Two studies were performed with meta-analysis, the other four studies existed some heterogeneity for which meta-analysis could not be performed, a significant effect on lung infiltrate absorption was found in the treatment groups of these two studies [RR 6.68, 95% CI (2.93, 15.24), P<0.01], there was no significant differences between the mortality [RR 0.86, 95% CI (0.22, 3.29), P = 0.82] and the average dosage of corticosteroid [WMD -39.65, 95% CI (-116.84, 37.54),P = 0.31]. The other three studies also showed significant differences in infiltrate absorption, including national drug No. 2. 3.4 in combination with Western medicine [RR 5.45,95% CI (1.54, 19.26)], compound formulas NO. 1 combined with Western medicine [WMD 0.24, 95% CI (0.02, 0.46)],compound formulas combined with Western medicine [RR 8.06, 95% CI (0.40, 163.21)]. Kangfeidian No.4 in combination with Western medicine had no significant effect on symptomim provement such as loss of dyspnea and cough [RR 1.50,95%CI (0.41, 5.43)] and [RR 1.29, 95%C1 (0.30, 5.43)].CONCLUSION: Integrated traditional Chinese and Westernm edicines has some positive effects on lung infiltrate absorption in SARS patients, and is recommended as an adjunct treatment for SAPS. However, its effect on SAPS requires further careful study due to limited available randomized control trials.

Loss of heterozygosity on hromosome 1 in sporadic colorectal carcinoma

AIM: Loss of heterozygosity (LOH) on tumor suppressor genes is believed to play a key role in carcinogenesis of colorectal cancer. When it occurs at a tumor suppressor gene locus with abnormal allele, neoplastic transformation happens. In this study, we analyzed the LOH at 21 loci on chromosome 1 in sporadic colorectal cancer to identify additional loci involved in colorectal tumorigenesis.METHODS: Twenty-one polymorphic micro-satellite DNA markers were analyzed with PCR both in 83 cases of colorectal cancer and in normal tissues. PCR products were eletrophoresed on an ABI 377 DNA sequencer. Genescan 3.1 and Genotype 2.1 software were used for LOH scanning and analysis. X^2 test was used to compare LOH frequency with clinicopathological data. P<0.05 was considered as statistically significant.RESULTS: The average LOH frequency of chromosome 1,short arm and long arm was 19.83%, 18.00% and 21.66%,respectively. The 2 highest LOH loci with a frequency of 36.54% and 32.50% were identified on DIS468 (1p36.33-p36.31) and DIS413 (1q31.3), respectively. On DIS2726 locus, LOH frequency of rectal cancer was 28.57% (6/21),which was higher than that of colon cancer (0.00%, 0/33) (P=0.002), suggesting that the mechanism of carcinogenisis was different in both groups.CONCLUSION: Putative tumor suppressor genes on chromosome 1 may relate to sporadic colorectal carcinomas.Tumor-suppressor-genes might locate on 1p36.33-36.31and/or 1q31.3.

Answering a century old riddle: brachydactyly type Al

In 1903, Farabee analyzed the heredity of the human digital malformation, brachydactyly, the first recorded disorder of the autosomal dominant Mendelian trait. In 1951, Bell classified this type of brachydactyly as type A1 (BDA1). Over 100 cases from different ethnic groups have so far been reported. However, the real breakthrough in identifying the cause of BDA1 has only taken place in the last few years with the progress of the mapping and identification of one of the genes responsible for this disorder, thus providing an answer for a century old riddle. In this article, we attempt to review the current state of knowledge on the genetic features of BDA1 with its century-old history and signalling pathway of IHH, and also discuss genotype-phenotype correlation not only of BDA1, but also of all types of brachydactyly.

Removal of NOx from flue gas with radical oxidation combined with chemical scrubber

In this paper, removal of NOx(namely DeNOx) from flue gas by radical injection combined with NaOH solution(26% by weight of NaOH in water) scrubbing was investigated. The experimental results showed that the steady streamer corona occurs through adjusting the flow rate of the oxygen fed into the nozzles electrode. The vapor in the oxygen has influence on the V I characteristics of corona discharge. Both HNO 2 and HNO 3 come into being in the plasma reactor and the DeNOx efficiency in the plasma reactor is more than 60%. The overall DeNOx efficiency of the whole system reaches 81 7% when the NaOH solution scrubbing is collaborated.

Detailed deletion mapping of loss of heterozygosity on 22q13 in sporadic colorectal cancer

AIM: Both development and progression of malignancies occur as a multistep process, requiring the activation of oncogenes and the inactivation of several tumor suppressor genes. The loss of heterozygosity (LOH) of tumor suppressor genes is believed to play a key role in carcinogenesis of colorectal cancer (CRC). In this study, we analyzed the LOH of seven loci on chromosome 22q13 in an effort to identify candidate tumor suppressor genes involved in colorectal carcinogenesis. METHODS: Matched tumor and normal tissue DNA were analyzed by PCR using fluorescence-labeled polymorphic microsatellite markers in 83 CRC patients. PCR products were eletrophoresed and LOH was determined by calculating the peak height acquired through computer software. Comparisons between LOH frequency and clinicopathological features were performed by x2 test. P<0.05 was considered as statistical significance. RESULTS: The average LOH frequency of chromosome 22q13 was 28.38%. The highest LOH frequency was 64.71% on D22S1160 locus, and the lowest was 21.43% on D22S1141 locus. We detected two obvious minimal deletion regions: one between markers D22S1171 and D22S274, the other flanked by markers D22S1160 and D22S1149, each about 2.7 and 1.8 cm, respectively. None had lost in all informative loci. LOH frequency on D22S1171 is 50% on distal colon, which was higher than that on proximal one (P= 0.020); on D22S114 locus, none LOH event occurred in patients with liver metastasis, whilst 46.94% occurred in patients without liver metastasis (P= 0.008); on D22S1160 locus, LOH frequency in lymph nodes metastasis patients was 83.33%, which was much higher than 43.75% without lymph nodes metastasis ones (P= 0.016). There was no statistical significance between clinicopathological features and other loci. CONCLUSION: This study provides evidence of two minimal deletion regions, which may harbor putative tumor suppressor genes related to progression and metastasis in sporadic colorectal carcinoma on chromosome 22q13.

Removal of NO_x by radical injection

Removal of NOx ( DeNOx, NOx is the total of NO and NO2) from flue gas by radical injection has been investigated . The discharge characteristics were examined and the steady streamer corona was acquired by adjusting the nozzle gases properly. It was found that an increase in the voltage resulted in a decrease in the NO concentration and the concentration of the NO2 increased at low voltages but decreased as the voltage rose to a certain level. The DeNOx efficiency increased as the applied voltage rose and reached a maximum of 70% when the voltage approached the break-down voltage. The hypothetical mechanism of NOx removal suggested that the radicals formed in the discharge process converted the NO and NO2 into acidic species. The Monte Carlo method was used to calculate the rate coefficients and the productivity of the radicals, and then the concentrations of both NO and NO2 and the DeNOx efficiencies were calcu-lated with chemical kinetics. The calculated DeNOx efficien-cies were comparable with the experimental DeNOx efficien-cies at low voltages, but were lower at high voltages.