[Relationship of ADC histogram parameters with pathological grade and lymph node metastasis of prostate cancer].

OBJECTIVE: To investigate the relationship between the apparent diffusion coefficient (ADC) histogram parameters based on the whole tumor and the pathological grade and lymph node metastasis (LNM) of PCa. METHODS: This retrospective study included 82 cases of PCa confirmed pathologically and subjected to MRI preoperatively. We obtained a series of ADC histogram parameters, such as ADCmean, ADCmedian, ADC25%, ADC75%, entropy, and histogram width, by processing the ADC images via the Firevoxel Post-Processing and the SPSS24 software. We compared the parameters between the high-risk and low- or moderate-risk groups as well as between the LNM-positive and LNM-negative groups of the patients, and analyzed the diagnostic performance of the parameters with statistically significant differences. RESULTS: The high-risk group, compared with the low- or moderate-risk one, showed a significantly lower ADCmean (ï¼»590 ± 120ï¼½ vs ï¼»837 ± 142ï¼½ ×10－6 mm2/s, P < 0.01), ADCmedian (ï¼»560 ± 117ï¼½ vs ï¼»804 ± 139ï¼½ ×10－6 mm2/s, P < 0.01), ADC25% (ï¼»446.5 ± 98ï¼½ vs ï¼»717 ± 118ï¼½ ×10－6 mm2/, P < 0.01) and ADC75% (ï¼»667 ± 132ï¼½ vs ï¼»931 ± 167ï¼½ ×10－6 mm2/s, P < 0.01). The ADCmean manifested the highest diagnostic performance, with an AUC of 0.907, a sensitivity of 0.933 and a specificity of 0.796. No statistically significant difference was found between the high-risk and the low- or moderate-risk one in entropy (3.58 ± 0.39 vs 3.63 ± 0.42, P = 0.238) or the histogram width (ï¼»540 ± 73ï¼½ vs ï¼»520 ± 65ï¼½ ×10－6 mm2/s, P = 0.086). Both entropy and the histogram width were remarkably higher in the LNM-positive than in the LNM-negative group (3.95 ± 0.41 vs 3.12 ± 0.45, P < 0.01; ï¼»578 ± 59ï¼½ vs ï¼»455 ± 68ï¼½ ×10－6 mm2/s, P < 0.01), and the former had an even higher diagnostic performance, with an AUC of 0.836, a sensitivity of 0.887 and a specificity of 0.781. There were no statistically significant differences between the LNM-positive and LNM-negative groups in the ADCmean (ï¼»768 ± 135ï¼½ vs ï¼»790±128ï¼½ ×10－6 mm2/s, P = 0.402), ADCmedian (ï¼»759 ± 110ï¼½ vs ï¼»775 ± 121ï¼½ ×10－6 mm2/s, P = 0.225), ADC25% (ï¼»643 ± 91ï¼½ vs ï¼»657 ± 89ï¼½ ×10－6 mm2/s, P = 0.654) or ADC75% (ï¼»895 ± 127ï¼½ vs ï¼»872 ± 129ï¼½ ×10－6 mm2/s, P = 0.926). CONCLUSIONS: ADC histogram parameters are related to pathological grade and LNM of PCa, and the analysis of the ADC histogram based on the whole tumor has an important value for preoperative evaluation and prognostic estimation of the malignancy.

[Evaluation of four kits for screening HIV antibody].

OBJECTIVE: To Evaluate four kits for screening HIV antibody by comparing and analyzing the HIV antibody screening positive results and Western Blot (WB) test results. METHODS: From January 2004 to June 2009, three ELISA kits (Zhongshan, Biomérieux and Livzon) were used for initial screening HIV antibody. The reactive positive samples were reexamed by initial ELISA kit and a rapid kit (Abbot Determine HIV-1/2). All repeatedly reactive positive screening results were followed by WB test. RESULTS: A total of 193 (0.094%) WB confirmed positive results were obtained from 206 151 specimens. The sensitivities and predictive values of negative test result (PVN) of three ELISA kits were all 100% and those of Abbot Determine HIV-1/2 were 93.93%, and 91.67% respectively. All false negative results from Abbot were WB indeterminate. The specificities of Zhongshan, Biomérieux, Livzon and Abbot were 99.88%, 99.89%, 99.96% and 89.38%; the study predictive values of a positive test result (PVP) were 35.58%, 46.46%, 76.61% and 92.20%; the efficiencies were 99.88%, 99.89%, 99.96% and 91.98%; the areas under ROC curve of the three ELISA kits were 0.93, 0.99, and 0.95 respectively. PVP of Livzon was obviously higher than those of Zhongshan (chi(2) = 45.804, P = 0.000), Biomérieux (chi(2) = 25.231, P = 0.000) and Biomérieux was higher than Zhongshan (chi(2) = 2.488, P = 0.115). PVP of Abbot was highest (chi(2) = 18.633, P = 0.000, vs Livzon). There were some specimens with S/CO (optical density of sample/cut off) ratio < 6 or > or = 6 in all three groups with positive, indeterminate and negative WB results. The S/CO ratio from Zhongshan in confirmed positive group (14.29 + or - 2.63) was higher than in positive-negative group (2.80 + or - 3.25) (t = 17.652, P = 0.000). The S/CO ratio from Biomérieux in confirmed positive group(16.09 + or - 2.35) was higher than in positive-negative group (2.14 + or - 1.91) (t = 31.622, P = 0.000). The S/CO ratio from Livzon in confirmed positive group (11.54 + or - 1.95) was higher than in positive-indeterminate group (5.54 + or - 3.57) (t = 6.386, P = 0.000), positive-negative group (3.25 + or - 2.41) (t = 21.772, P = 0.000) and positive-indeterminate group was higher than positive-negative group (t = 2.301, P = 0.033). CONCLUSION: The performances of four HIV antibody screening kits are good but estimating WB confirming result in line with S/CO ratio is not available. All repeated screening positive results should be followed by confirmatory tests.

Protein structure determination using a Riemannian approach.

Protein NMR structure determination is one of the most extensively studied problems. Here, we adopt a novel method based on a matrix completion technique - the Riemannian approach - to rebuild the protein structure from the nuclear Overhauser effect distance restraints and the dihedral angle restraints. In comparison with the cyana method, the results generated via the Riemannian approach are more similar to the standard X-ray crystallographic structures as a result of the simple but powerful internal calculation processing function. In addition, our results demonstrate that the Riemannian approach has a comparable or even better performance than the cyana method on other structural assessment metrics, including the stereochemical quality and restraint violations. The Riemannian approach software is available at: https://github.com/xubiaopeng/Protein_Recon_MCRiemman.

An Extreme Learning Machine Based on Artificial Immune System.

Extreme learning machine algorithm proposed in recent years has been widely used in many fields due to its fast training speed and good generalization performance. Unlike the traditional neural network, the ELM algorithm greatly improves the training speed by randomly generating the relevant parameters of the input layer and the hidden layer. However, due to the randomly generated parameters, some generated "bad" parameters may be introduced to bring negative effect on the final generalization ability. To overcome such drawback, this paper combines the artificial immune system (AIS) with ELM, namely, AIS-ELM. With the help of AIS's global search and good convergence, the randomly generated parameters of ELM are optimized effectively and efficiently to achieve a better generalization performance. To evaluate the performance of AIS-ELM, this paper compares it with relevant algorithms on several benchmark datasets. The experimental results reveal that our proposed algorithm can always achieve superior performance.

[Effect of the complex of casein phosphopeptide and amorphous calcium phosphate on reducing enamel demineralization and promoting remineralization].

OBJECTIVE: To investigate the effect of the complex of casein phosphopeptide and amorphous calcium phosphate (CPP-ACP) on the demineralization and remineralization of dental enamel in vitro. METHODS: Premolars extracted from patients receiving orthodontic treatment were cut into two slabs, which were embedded and polished. The slabs were randomly divided into non-acid etching group, acid etching group (immersed in 37.5% phosphoric acid for 2 minutes), experimental group A (immersed in 37.5% phosphoric acid for 2 minutes and wiped by CPP-ACP for 3 minutes, then immersed in distilled water for 7 days), experimental group B (immersed in 37.5% Phosphoric acid for 2 minutes and wiped by CPP-ACP for 3 minutes, then immersed in distilled water for 14 days), experimental group C (immersed in 37.5% phosphoric acid for 2 minutes and wiped by CPP-ACP for 3 minutes, then immersed in distilled water for 21 days), experimental group D (immersed in 37.5% phosphoric acid for 2 minutes and wiped by CPP-ACP for 3 minutes, then immersed in distilled water for 28 days), with 6 slabs in each group. The mineral content was determined by scanning electron microscope. RESULTS: There was a large amount of mineral deposited on enamel surface in experimental group A, B, C, D. The calcium content of experimental group D was higher than those of other 3 experimental groups. The calcium content of experimental group A, B, C, D (66.53 ± 0.63, 67.00 ± 0.49, 67.07 ± 0.24, 67.18 ± 0.50) was higher than that of acid etching group (65.74 ± 0.68) (P < 0.05). There was no significant difference of the calcium content among experimental group A, B, C, D (P > 0.05). CONCLUSIONS: CPP-ACP can reduce enamel demineralization and promote remineralization in vitro.

[Correlations between preS1-antigen, HBV-DNA and HBV serum markers in patients with chronic hepatitis B].

OBJECTIVE: To study the correlations between preS1 antigen, HBV-DNA and hepatitis B virus (HBV) serum markers in patients with chronic hepatitis B. METHODS: The HBV markers, preS1 antigen and HBV-DNA were determined using enzyme- linked immunosorbent assay and quantitative PCR in 1158 patients with chronic hepatitis B. RESULTS: In these patients, the HBV-DNA positivity rate was 68.9%, significantly higher than preS1 antigen positivity (54.8%, chi2=53.24, P<0.005). The positivity rates of both HBV-DNA and PreS1-antigen were significantly higher in HBeAg-positive patients than in HBeAg-negative patients (P<0.005). The coincident rates of preS1-antigen and HBeAg with HBV-DNA were 56.9% and 63.3%, respectively. PreS1 antigen had higher sensitivity but lower specificity than HBeAg. The detection rates of preS1 antigen and HBeAg increased with the level of HBV-DNA, and preS1 antigen positivity was higher than that of HBeAg in patients with low HBV-DNA levels. CONCLUSION: Detection of HBV serum markers along with preS1 antigen and HBV-DNA may help assess the status of viral replication and therapeutic efficacy in patients with chronic hepatitis B. PreS1 antigen may serve as an auxiliary indicator in HBeAg-negative cases or when HBV-DNA detection is impossible.