[Simultaneous detection of 7 important Rickettsiales pathogens by TaqMan-probe quantitative real-time PCR].

Objective: To establish and optimize a TaqMan-probe quantitative real-time PCR (qPCR) assay for the detection of 7 important Rickettsiales pathogens and simultaneous identification of the infection types. Methods: Based on the ompB gene of Rickettsia prowazekii, Rickettsia mooseri and spotted fever group rickettsiae, the groEL gene of Orientia tsutsugamushi, the 16S rRNA of Ehrlichia chaffeensis, the gltA gene of Anaplasma phagocytophilum and the com1 gene of Coxiella burnetii, we synthesized primers and TaqMan-probes and optimized the reaction system and reaction process to same solution. The sensitivity, specificity and reproducibility of this assay were evaluated and the assay was used for the detection of simulated and actual samples. Results: The Ct value of the standard curves of the 7 pathogens showed a good linear relationship with the number of DNA copies (all R2 >0.990 0), the minimum detection limit was 10 copies/µl, showing good specificity. In the 96 tick nucleic acid extracts, Coxiella burnetii was detected in 1 sampleand spotted fever group Rickettsiae was detected in 3 samples. In the 80 blood samples from patients with undefined febrile illness, Orientia tsutsugamushi was detected in 1 sample and spotted fever group rickettsiae was detected in 2 samples. Conclusions: In this study, based on the established TaqMan-probe qPCR assay, the reaction system and reaction condition of the 7 important pathogens of Rickettsiales were optimized to the same solution. This method overcomes the shortcomings of using different reaction systems and reaction conditions for different pathogens, which can precisely identify the species of 7 important pathogens of Rickettsiales in clinical sample detections and is important for the infection type identification and laboratory detection time reduction to facilitate precise treatment of the patients.

Contrast-enhanced ultrasound at high mechanical index: a new method for transjugular intrahepatic portosystemic shunt follow-up.

AIM: To evaluate the diagnostic value of contrast-enhanced ultrasound (CEUS) at high mechanical index (MI) for transjugular intrahepatic portosystemic shunt (TIPS) follow-up. MATERIALS AND METHODS: Fifty patients with a suspected diagnosis of shunt dysfunction were enrolled in the present study. The patients were divided into three groups: colour Doppler flow imaging (CDFI), CEUS at low MI and CEUS at high MI. The portography was used as the reference standard regarding the ability to identify shunt abnormalities. The sensitivity, specificity, area under the curve (AUC), positive predictive value, and negative predictive value were calculated. RESULTS: Out of 50 patients with a suspected diagnosis of shunt dysfunction, 18 (36%) patients had abnormal portogram findings, among which there were eight shunt occlusions and 10 stent stenosis. The sensitivity, specificity, and AUC for shunt abnormalities of CEUS at high MI are 94.4%, 93.8%, and 94%, respectively. CDFI was less sensitive and accurate than CEUS at low or high MI regarding shunt abnormality identification. Although the diagnostic results of CEUS at high MI offered relatively higher sensitivity/accuracy and correlated better with portography than that of CEUS at low MI, the difference between CEUS at low MI and high MI was not significant. The diagnostic accuracy of CDFI, CEUS at low MI, and CEUS at high MI are 50%, 70%, and 80% respectively. CONCLUSIONS: With the relatively high sensitivity and specificity compared with CDFI and CEUS at low MI, CEUS at high MI offers an alternative complementary new method to detect TIPS abnormalities in clinic.

[Establishment of the Mathematical Model for PMI Estimation Using FTIR Spectroscopy and Data Mining Method].

OBJECTIVES: To analyse the relationship between Fourier transform infrared （FTIR） spectrum of rat's spleen tissue and postmortem interval （PMI） for PMI estimation using FTIR spectroscopy combined with data mining method. METHODS: Rats were sacrificed by cervical dislocation, and the cadavers were placed at 20 ℃. The FTIR spectrum data of rats' spleen tissues were taken and measured at different time points. After pretreatment, the data was analysed by data mining method. RESULTS: The absorption peak intensity of rat's spleen tissue spectrum changed with the PMI, while the absorption peak position was unchanged. The results of principal component analysis （PCA） showed that the cumulative contribution rate of the first three principal components was 96%. There was an obvious clustering tendency for the spectrum sample at each time point. The methods of partial least squares discriminant analysis （PLS-DA） and support vector machine classification （SVMC） effectively divided the spectrum samples with different PMI into four categories （0-24 h, 48-72 h, 96-120 h and 144-168 h）. The determination coefficient （R²ï¼‰ of the PMI estimation model established by PLS regression analysis was 0.96, and the root mean square error of calibration （RMSEC） and root mean square error of cross validation （RMSECV） were 9.90 h and 11.39 h respectively. In prediction set, the R² was 0.97, and the root mean square error of prediction （RMSEP） was 10.49 h. CONCLUSIONS: The FTIR spectrum of the rat's spleen tissue can be effectively analyzed qualitatively and quantitatively by the combination of FTIR spectroscopy and data mining method, and the classification and PLS regression models can be established for PMI estimation.

Folic acid-conjugated graphene oxide for cancer targeted chemo-photothermal therapy.

Nanographene oxide (NGO), a new type of nanomaterial for anticancer drugs delivery and near-infrared (NIR)-mediated photothermal ablation of tumors, has been used in the combination of photothermal therapy and chemotherapy. Herein, targeted chemo-photothermal therapy based on polyvinylpyrrolidone (PVP) functionalized NGO was achieved. Folic acid (FA), a common target molecule to cancer cells, was conjugated to NGO via covalent amide bond. The obtained FA-NGO-PVP was proved to be an ideal pH-responsive nanocarrier for delivery of an anticancer drug doxorubicin (DOX) with the loading ratio more than 100%. In vitro experiments were then performed with the combination of chemotherapy and NIR photothermal therapy. The results demonstrated that the targeted chemo-photothermal therapy could specifically deliver drug and heat to tumor sites and showed excellent efficacy of anticancer therapy. Thus, FA-NGO-PVP could be used as a novel nanomaterial for selective chemo-photothermal therapy.

Genetic evidence for domestic raccoon dog rabies caused by Arctic-like rabies virus in Inner Mongolia, China.

An outbreak of rabies affected domestic raccoon dogs on an animal farm in Inner Mongolia, China in 2007. A study was conducted to characterize the aetiological agent and clarify the origin of the rabies virus. Brain tissues were obtained from five rabid raccoon dogs. Viral nucleoprotein antigen was detected in the brain tissues and five rabies viruses were isolated from these rabid animals. Phylogenetic analysis of the N and G gene sequences showed that these isolates were closely related to Arctic-like rabies viruses isolated from the far-eastern region of Russia and South Korea, but distinct from the rabies viruses that are widely distributed in endemic areas in China. Epidemiological data suggested that the likely source of infection was from one wild raccoon dog that was captured and placed in the same type of pen used for domestic raccoon dogs.

Analysis of neurotoxin 3-N-oxalyl-L-2,3-diaminopropionic acid and its alpha-isomer in Lathyrus sativus by high-performance liquid chromatography with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) derivatization.

A method was developed for the quantitative determination of the neurotoxic nonprotein amino acid, 3-N-oxalyl-L-2,3-diaminopropionic acid (beta-ODAP), and its nontoxic alpha-isomer, 2-N-oxalyl-L-2, 3-diaminopropionic acid (alpha-ODAP), in the plant samples of Lathyrus sativus after derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) by reversed-phase high-performance liquid chromatography (HPLC). Hippuric acid was used as an internal standard. A linear response was recorded in the concentration rang 0.32-32 nmol with r > 0.999. The RP HPLC detection limit for both isomers is 1.8 ng. According to different experimental needs, a ternary gradient system can be used to determine toxin and other nonprotein amino acids. The RP HPLC method and a colorimetric method were compared for measuring ODAP.