Different Re-centrifugation Conditions for Infectious Disease Screening Using the Abbott I2000.

We investigated whether an ordinary centrifuge can achieve the standard centrifugal effect required according to specifications for infectious disease screening using the Abbott i2000. Samples were collected and centrifuged following a standard operating procedure (SOP). They were then divided into three groups according to the results of the initial screening tests: a negative group, weak-positive group, and positive group. Twenty negative samples and all weak-positive and positive samples were re-analyzed. Two tubes for each re-analyzed sample were centrifuged simultaneously, one for 10 min at 10 000 × g, per recommendations, and one for 10 min at 2750 × g. No significant difference was found between the groups using different centrifugal forces. There was a strong correlation in the quantitative values between the two conditions of centrifugation. Consistency analysis showed a Cronbach's alpha > 0.8 for detection of Treponema pallidum, human immunodeficiency virus (HIV), hepatitis C virus (HCV), and hepatitis B surface antigen in the three groups (negative group, weak-positive group, and positive group) under different centrifugation conditions. Strong consistency was found under different centrifugal conditions, regardless of the initial testing results. In conclusion, we conducted centrifugation steps in duplicate, according to infectious disease screening protocols. Our study showed that all samples should be centrifuged using a recommended relative centrifugal force after a proper clotting time, as in the standard operating procedure of our laboratory. In this way, we were able to obtain the same results using an ordinary centrifuge as those obtained using a high-speed centrifuge, such as the Abbott i2000.

Three-phase partitioning system with dimethyl carbonate as organic phase for partitioning of exopolysaccharides from Phellinus baumii.

In this study, a three-phase partitioning (TPP) system with dimethyl carbonate (DMC) as organic phase and sodium citrate (SC) as salt phase was used for partitioning of exopolysaccharide (EPS), namely, EPS-D, from fermentation broth of Phellinus baumii. Results showed that the maximum extraction yield (EY) of EPS-D was 71.02% under the following modified optimal conditions: DMC to fermentation broth ratio 0.5:1.0 (v/v), SC concentration 19% (w/v), temperature 30 °C, and pH 4.0. EPS-D had higher EY, carbohydrate, and uronic acid contents compared with the EPS, designated as EPS-T, obtained from the TPP system with t-butanol and ammonium sulfate. EPS-D and EPS-T had different chemical compositions and molecular weights; however, their preliminary chemical structures basically remained unchanged. Moreover, EPS-D exhibited stronger free radical-scavenging capability and total antioxidant capacity than EPS-T. Therefore, the TPP system with DMC as an alternative solvent for t-butanol has great potential for efficient partitioning of natural biomolecules.

Inhibitory Effect of Vaginal Lactobacillus Supernatants on Cervical Cancer Cells.

Lactobacilli have been shown to inhibit the proliferation of several types of cancer cells, but the effects of vaginal Lactobacilli on cervical cancer cells have seldom been reported. We incubated Caski cells with supernatants of predominant strains in the vagina and investigated their effects on cell growth and the possible mechanisms. Cell-free supernatants of Lactobacillus crispatus, L. jensenii, and L. gasseri were prepared and purified. Caski cells were treated with various concentrations of Lactobacillus supernatants (LS). The effect of LS on cell growth was investigated using MTT assays. The influence of LS on the cell cycle and expression of human papillomavirus (HPV) E6 and E7 oncogenes was determined by flow cytometry and RT-PCR, respectively. LS-inhibited Caski cell proliferation caused morphological changes in a pH-independent manner. Flow cytometric analysis revealed that cells exposed to LS exhibited a significant increase of cell number in S phase and a strong decrease of cell number in G2/M phase. Expression of HPV E6 and E7 oncogenes, as well as CDK2 and cyclin A was decreased after treatment with LS, while expression of p21 was increased. Supernatants of L. crispatus, L. jensenii, and L. gasseri have inhibitory effects on the viability of cervical cancer cells via regulation of HPV oncogenes and cell cycle-related genes. Lactobacillus, as a promising treatment for cancer, is being assessed for its effect, and these results provide further evidence in this respect.

Preferable procedure for the screening of syphilis in clinical laboratories in China.

BACKGROUND: With the rapid expansion of infectious syphilis all over the world, optimal procedures for screening syphilis are urgently required. Conventional methods for the diagnosis of syphilis are time- and labor-consuming. We compared automated chemiluminescent micro-particle immunoassay (CLIA) with conventional methods to verify whether CLIA is feasible for syphilis screening. METHODS: A cross-sectional assay was conducted on 3962 serum samples tested by CLIA, rapid plasma reagin test (RPR), and Treponema pallidum particle agglutination (TPPA). Meanwhile, another 36 000 sera were screened for syphilis using CLIA and the positive samples were confirmed using TPPA, RPR or Western blotting. RESULTS: The sensitivity and specificity were 100% and 99.8% for CLIA, and 65% and 99.6% for RPR. With the elevation of the optical density value of samples to cut-off ratio (S/CO) value, the true-positive rate of CLIA increased significantly, and when the S/CO value exceeded 10, the true-positive rate of CLIA reached 100%. The false-positive rate of CLIA was 0.22%; pregnant women had the most false-positive results, followed by elderly people and cancer patients. CONCLUSION: CLIA is suggested as a screening test for the diagnosis of syphilis, while TPPA and RPR are required for confirming the positive samples and monitoring their activity.

Quantification of Atopobium vaginae loads may be a new method for the diagnosis of bacterial vaginosis.

BACKGROUND: Traditional methods for the diagnosis of BV is either with poor sensitivity or poor specificity. Thus, establishing a new method based on the vaginal flora is vital for the diagnosis of BV. METHODS: This article is a retrospective research. Based on the Amsel criteria and Nugent score, 230 BV-positive patients and 360 healthy women were enrolled, specific PCR and quantitative PCR were applied to quantify 5 BV-associated bacteria, including Gardnerella vaginalis, Atopobium vaginae, Leptotrichia/Sneathia species, Megasphaera species and Mobiluncus mulieris. ROC curve was facilitated to screen a bacterial panel with optimal sensitivity and specificity. RESULTS: Specific PCR showed that the area under ROC curve of A.vag, G.vag + A.vag, G.vag + A.vag + Lepto, G.vag + A.vag + Mega and G.vag + A.vag + M.mul were 0.845, 0.862, 0.865, 0.869 and 0.867, the sensitivity and specificity were higher than 80%, which were practicable methods for the diagnosis of BV. Quantitative PCR showed the area under ROC curve of Gardnerella vaginalis, Atopobium vaginae, Leptotrichia/Sneathia species, Megasphaera species and Mobiluncus mulieris were 0.959, 0.996, 0.933, 0.748 and 0.639, when the cutoff value of Atopobium vaginae loads was 247,800 copies/mL, the optimal sensitivity and specificity were 0.979 and 0.952, which was distinctly better than specific PCR. CONCLUSIONS: Quantification ofAtopobium vaginae loads may be a new method of excellent sensitivity and specificity for the diagnosis of BV.

Chemokine CXC Ligand 16 serum concentration but not A181V genotype is associated with atherosclerotic stroke.

BACKGROUND: Serum chemokine CXC Ligand 16 (CXCL16) concentration is associated with atherosclerosis and CXCL16 expression may be influenced by the polymorphism, A181V. We established whether serum CXCL16 concentration or the A181V genotype is more strongly associated with atherosclerotic stroke and its associated risk factor, carotid atherosclerosis. METHODS: PCR-RFLP was used to genotype 244 atherosclerotic stroke patients (AS group), 153 stroke-free controls (patient controls) and 167 healthy controls. Serum CXCL16 concentration was determined for a subset of patients (n=135) and all controls. The same subset of patients was then examined using ultrasound to evaluate their carotid atherosclerotic lesions, including intima-media thickness (IMT), plaque stability and carotid plaque area (CPA). RESULTS: Compared with the patient controls and healthy controls, serum CXCL16 concentration was significantly increased in the AS group (P<0.05, and 0.01). It was also strongly associated with increased IMT, vulnerable plaque and increased CPA (P<0.05, <0.001, and <0.01). However, the CXCL16 A181V genotype distribution and allele frequencies showed no differences between AS and control groups, nor did it influence serum CXCL16 concentration. CONCLUSION: Serum CXCL16 concentration is significantly associated with atherosclerotic stroke and carotid atherosclerosis, suggesting that this biochemical test may be useful to identify patients at increased risk of atherosclerosis.