[Application of surface-enhanced Raman spectroscopy to the determination of trace chemical hazards in food products].

In the present review, we summarized the research progress in applying SERS for the determination of illegal food additives, residual pesticides, banned or restricted antibiotics and other drugs. The nanosubstrates used in these studies included, but were not limited to, gold and silver nanosphere colloids, solid surface gold coated nanosubstrates, bimetallic nanosubstrates and spherical magnetic-core gold-shell nanoparticles, and etc. Standard solutions of a targeted chemical were normally tested first before analysis of relevant food in which the targeted chemical was commonly detected, and the tested food products included dairy products, condiments (such as chili powder and spices), fish, fruits and vegetables. The intensity of surface-enhanced Raman scattering signal is affected by various factors, which makes it difficult to obtain reproducible spectra. In addition, interferences of non-targeted food components on the target molecules during SERS analyses further makes it difficult to apply SERS as a routine analytic technique, despite its high specificity and sensitivity. Nevertheless, SERS is a new tool with great potential for analysis of trace amounts of chemical hazards in various food products and other complex systems.

[Identification and expression of cytochrome C in tumor-bearing mice model with neuroblastoma].

OBJECTIVE: To screen, identify and verify the serum specific protein of neuroblastoma in a tumor-bearing murine model and speculate about the source of cytochrome C. METHODS: NB cells (KP-N-NS) were inoculated subcutaneously into nude mice. And the sera samples of tumor-bearing mice (observation group, n = 14) and controls (control group, n = 25) were collected at 4 weeks to screen for and identify differentially expressed proteins. The method of surface-enhanced laser desorption-ionization time-of-flight mass spectrometry (SELDI-TOF-MS) was employed to screen the serum specific protein of neuroblastoma between two groups. Then serum protein targets were purified by high-performance liquid chromatography (HPLC) and identified by LC-MS/MS (LTQ). RESULTS: By comparing protein peaks among two sera groups, we identified the peak (11 609) showing significant differential expression between two groups. The expression of peak (11 609) was 3338.4 ± 1410.9 in observation group and 59.8 ± 40.7 in control group. This peak was identified as murine cytochrome C. CONCLUSION: Cytochrome C is a serum specific protein for neuroblastoma tumor and it comes from the apoptosis of non-tumor cells.

[Relationship between mRNA expression and promoter methylation status of p73 gene in peripheral blood among children with Wilms' tumor].

OBJECTIVE: To investigate the mRNA expression and promoter methylation status of p73 gene in the peripheral blood of children with Wilms' tumor (WT), and their relationship. METHODS: Forty-five children with WT were selected as the case group, and 15 sex- and age- matched children (without malignancies) who visited the hospital for physical examination or other reasons were selected as the control group. Peripheral blood was collected from both groups. Real-time quantitative PCR and methylation-specific PCR were used to determine the mRNA expression level and promoter methylation status of p73 gene. Their relationship with clinicopathological features and the effect of promoter methylation on mRNA expression of p73 gene were analyzed in the case group. RESULTS: The relative quantity (RQ) of p73 mRNA in the case group was significantly higher than in the control group (3.2 ± 0.9 vs 1.6 ± 1.1; P<0.01). The positive rate of p73 gene promoter methylation in the case group was significantly lower than in the control group (20% vs 73%; P<0.01). In the case group, the RQ of p73 mRNA was significantly higher in children with methylated p73 gene promoter than in those with unmethylated p73 gene promoter (P<0.01). In children with methylated p73 gene promoter, the RQ of p73 mRNA was significantly higher in the case group than in the control group (P<0.01). In children with unmethylated p73 gene promoter, there was no significant difference in RQ of p73 mRNA between the case and control groups (P=0.810). CONCLUSIONS: Aberrant promoter methylation of p73 gene in peripheral blood is one of the gene expression regulations in children with WT, and it is related to the onset and development of WT. The p73 gene may play a role as oncogene in WT patients with p73 gene promoter methylation and mRNA overexpression is associated with promoter methylation status of p73 gene.

[Qualitative and quantitative detection of minced pork quality by near infrared reflectance spectroscopy].

The present study is concerning qualitative and quantitative detection of minced pork quality based on FT-near infrared (FT-NIR) spectroscopy and achieving the rapid approach to detecting the minced pork quality. Firstly, FT-NIR spectroscopy combined with partial least squares (PLS) and least squares-support vector machine (LS-SVM) was used for minced pork quality prediction including discrimination of the different muscle type of pig and quantitative detection of the fat, protein and moisture content of pork. The result indicated that 100% recognition ratio for calibration and 96% recognition ratio for validation were achieved by PLSDA for 4 different muscle types of pig. These two methods for chemical composition detection both have good performances in predicting fat and moisture content, the correlation coefficient for calibration and validation was all more than 0.9, but the models for protein content prediction were of less well performances, the correlation coefficients for calibration and validation, RMSEC, RMSEP and RMSECV respectively were 0.722, 0.593, 1.595, 1.550 and 1.888, respectively. The LS-SVM method is more accurate in predicting each quality index than the PLSR method. The result shows that the prediction models for fat and moisture content based on LS-SVM have a better performance with high precision, good stability and adaptability and can be used to predict the fat and moisture content of minced pork rapidly, and provide a fast approach to discrimination of the different muscle type of pig.

[Prediction of minced pork quality attributes using visible and near infrared reflectance spectroscopy].

The objective of the present study was to estimate minced pork meat quality using visible and near infrared (Vis-NIR) spectroscopy. Two hundred twenty five carcasses samples from longissimus dorsi muscle were scanned over the Vis-NIR spectral range from 350 to 1 015 nm and analysed for intramuscular fat (IMF), protein and moisture according to the official methods. Wavelet transform was employed to eliminate the spectra noise. Partial least square regression (PLSR) and support vector machine (SVM) were used to develop Vis-NIR spectroscopy models for chemical composition detection. According to calibration statistics, the best model to predict intramuscular fat content was developed by SVM with the denoised spectra, the correlation coefficient was 0.889 for calibration and 0.888 for validation. For protein and moisture, the best model was achieved with the PLS method with the correlation coefficient of 0.869 and 0.881 for protein calibration and validation sets and 0.877 and 0.848 for moisture calibration and validation sets, respectively. And all the ratios of standard deviation of validation set to root mean square error of prediction (RPD) were not more than 3.0. Results indicated that it was possible to predict chemical composition in minced pork meat. As a fast predictor of meat quality using Vis-NIR spectroscopy, it is necessary to improve the precision and the robustness of the model for practice.

[Online determination of pH in fresh pork by visible/near-infrared spectroscopy].

The present research was focused on determination of the pH value online by visible and near-infrared spectroscopy. In the part of data gathering, fresh pork longissimus dorsi was moving at the constant velocity of 0.25 m x s(-1) on the conveyor belt, and the visible and near-infrared diffuse reflectance spectrum (350-1 000 nm) was captured. In the part of data processing, band of 510-980 nm of the spectra was chosen to calibrate reflex distance, then to set up online detection model of pH value in fresh pork by partial least squares regression (PLSR). Kennard-stone algorithm was applied to divide the samples to the calibration set and validation set. The performances of several PLSR models employing various preprocessing methods including multiple scatter correction, derivative and both of them combined were compared. Further, the best performance model was optimized by interval PLSR to decrease the modeling variables of wavelength. The results indicated that the PLSR model based on preprocessing of multiple scatter correction (MSC) combined with first derivative gave the best performance with 0.905 of the correlation coefficient for validation set and 0.051 of the root of mean square errors for validation set. For the best PLSR model performance, the correlation coefficient of validation set increased to 0.926 and the root of mean square errors for validation set to 0.045 in the optimization interval PLSR model. However, only half of variables were used. The research demonstrates that using visible and near-infrared spectroscopy to determine fresh pork pH online is feasible.

[Detection and identification of specific serum biomarkers in papillary thyroid cancer].

OBJECTIVE: To detect and identify the potential specific serum biomarkers for diagnosis of papillary thyroid cancer. METHODS: Samples of 35 patients with papillary thyroid carcinoma, 40 patients with benign thyroid nodule and 34 healthy individuals were analyzed using the SELDI-TOF ProteinChip System and bioinfomation technology to find the differential peaks which were separated by HPLC and then further analyzed by LC-MS/MS. The protein sequences were analyzed by SEQUEST software and searched in Bioworks database. RESULTS: The top six mass-to-charge ratio (M/Z) peaks with the smallest P value were 6651, 6452, 7653, 7932, 15 106 and 15 848 Da, respectively. The 6651 and 6452 Da proteins were weakly expressed in papillary thyroid carcinoma but highly expressed in benign thyroid nodules and healthy individuals. The differences had statistical significance (P < 0.01). The 7653, 7932, 15 106, 15 848 Da proteins were highly expressed in papillary thyroid carcinoma but weakly expressed in benign thyroid nodules and healthy individuals. The differences were statistically significant (P < 0.01). Combination of these six proteins, using the method of leave-one-out to make crossing detection, the specificity of discriminating papillary thyroid carcinoma and non-cancer was 88.0%, and its sensitivity was 92.5%. The 6651 and 6452 Da proteins were identified as apolipoprotein C-I and apolipoprotein C-III, respectively. The 7653 and 15 106 Da proteins were identified as the same protein-alpha-globin, and the 7932 and 15,848 Da proteins were identified as the same protein-beta-globin. CONCLUSION: The detection of differentially expressed apolipoprotein C-I, apolipoprotein C-III, alpha-globin, and beta-globin may have utility for diagnosis of papillary thyroid carcinoma and are worthy of further investigation.

[Screening and identification analysis of serum protein biomarkers in nephroblastoma].

OBJECTIVE: To screen and characterize the serum protein biomarkers in nephroblastoma so as to establish the proteins as the specific serum biomarkers for diagnosis and prognosis monitoring. METHODS: The differential protein peaks were located by detecting serum samples of preoperative and postoperative patients and normal children using the SELDI-TOF MS technology. After purification, the differential proteins were further analyzed by LC-MS/MS and the protein sequences searched in database. RESULTS: Two peaks with m/z of 6455.5 and 6984.4 were selected as potential biomarkers. They were weakly expressed in nephroblastoma (intensity: 1029 +/- 364, 297 +/- 126) but highly expressed in normal individuals (2108 +/- 837, 753 +/- 226); another peak with m/z of 9190.8 was weakly expressed in preoperative sera (283 +/- 154) but highly expressed in serum samples of postoperative patients and normal children (5974 +/- 657, 6231 +/- 519). The protein at 6455.5 and 9190.8 were identified as apolipoprotein C-III and haptoglobin respectively. CONCLUSION: The detection of differentially expressed apolipoprotein C-III and haptoglobin may have potential utilities for serum diagnosis, malignancy classification and prognosis monitoring of nephroblastoma and is worthy of further studies and applications.

[Qualitative analysis of fragrant pear class based on near infrared diffuse reflectance spectroscopy].

A method was developed to automatically discriminate the persistent calyx fruit and fruit without calyx of fragrant pear by means of near infrared spectroscopy (NIRS). The prediction performance of different band regions range, different principal component numbers and different preprocessing methods of the spectra (multiplicative signal correction, standard normal variate, and derivative spectra) together with discriminant analysis (DA) was also investigated, and The calibration model was established to classify the different kinds of fragrant pear. The research results for the fragrant pear classification showed that DA calibration models using these parameters with band regions between 9 091 and 4 000 cm(-1) and original spectra are optimal, with the percentage of correct sample classification being 100% and 95% for the calibration and validation set, respectively.

Carbon nanoparticle lymph node tracer improves the outcomes of surgical treatment in papillary thyroid cancer.

BACKGROUND: Papillary thyroid carcinoma (PTC) is the most common thyroid malignancy which is generally accompanied by lymph node metastasis. OBJECTIVE: Our study evaluated whether carbon nanoparticle lymph node tracer can improve the outcomes of surgical treatment in papillary thyroid cancer (PTC). METHODS: Ninety-two patients were selected and underwent total thyroidectomy and lymph node resection. Our study placed 45 individuals into the treatment group (carbon nanoparticle group) and 47 cohorts in the control group (no carbon nanoparticle group). RESULTS: Carbon nanoparticle application remarkably improved lymph nodes detection rate in patients (4.7 ± 3.0; P< 0.05) compared to those in control groups (3.5 ± 2.3). The rate of parathyroid accidental resection in the carbon nanoparticle group significantly decreased (6.67%) compared to the control group (21.28%). Incidents of hypoparathyroidism and hypocalcaemia significantly decreased among the carbon nanoparticle cohorts. CONCLUSIONS: Our study definitively showed that carbon nanoparticles can be used to effectively treat lymphatic carcinoma. Our study presented clinical evidences for potential application of carbon nanoparticle in improving the management of PTC patients.

LncRNA PTCSC3 affects drug resistance of anaplastic thyroid cancer through STAT3/INO80 pathway.

BACKGROUND: LncRNA PTCSC3 is a tumor suppressor in thyroid cancer, and its role in drug resistance of anaplastic thyroid cancer (ATC) to chemotherapy drug doxorubicin was investigated in this study. METHODS: Expression of RNA and protein was analyzed by qRT-PCR and western blot, respectively. Flow cytometry was used to analyze the expression rate of CD133+ cells. The endogenous expression of related genes was modulated by recombinant plasmids and cell transfection. Combination condition and interaction between PTCSC3 and STAT3 were determined by RIP and RNA pull-down assay, respectively. MTT assay was performed to detect cytotoxicity. Chromatin immunoprecipitation was conducted to identify interactions between STAT3 and DNA promoter of INO80. RESULTS: LncRNA PTCSC3 was low-expressed in ATC tissues and cells. Over-expressed PTCSC3 inhibited the drug resistance of ATC to doxorubicin. PTCSC3 negatively regulated STAT3, and STAT3 promoted expression of INO80. PTCSC3 regulated INO80 through STAT3. PTCSC3 suppressed stem cells properties and drug resistance of ATC to doxorubicin. CONCLUSION: LncRNA PTCSC3 inhibits INO80 expression by negatively regulating STAT3, and thereby attenuating drug resistance of ATC to chemotherapy drug doxorubicin.

DNA methyltransferase 3b silencing affects locus-specific DNA methylation and inhibits proliferation, migration and invasion in human hepatocellular carcinoma SMMC-7721 and BEL-7402 cells.

DNA methylation is an important regulator of gene transcription, and its role in carcinogenesis has been a topic of considerable interest in previous years. The present study examined the influence of DNA methyltransferase 3b (DNMT3b) on cell proliferation, migration and invasion, and the methylation status of identified tumor suppressor genes in hepatoma SMMC-7721 and BEL-7402 cells. DNMT3b was silenced by small interfering RNA (siRNA) in human hepatocellular carcinoma cell lines. Transfection efficiency was verified using a fluorescent imaging system, reverse transcription polymerase chain reaction (RT-PCR) and western blotting. A cell proliferation assay was performed to evaluate cell viability. Cell cycle distribution and apoptosis were analyzed by flow cytometry. The migratory and invasive ability of cells was measured using a Transwell assay. Methylation-specific PCR (MSP) was performed to assess methylation in the promoter region of genes. The present data revealed that DNMT3b siRNA successfully inhibited expression of the DNMT3b gene in these two liver cancer cell lines and therefore inhibited the proliferation of the transfected cells, stimulated apoptosis in the cells, led to an accumulation of cells in the G2/M phase and decreased cell migration and invasion. It was also found that silencing DNMT3b expression results in hypomethylation of specific sets of gene promoters and increases the expression of distinct set of genes in HCC cell lines. The present study is therefore useful for assessing the specificity of emerging action based on the altered expression of associated regulatory genes, particularly in methylation-silenced genes.

Identification of potential plasma biomarkers for esophageal squamous cell carcinoma by a proteomic method.

Among malignant tumors, the mortality rate of esophageal squamous cell carcinoma (ESCC) ranks sixth in the world. Late-stage diagnosis of ESCC increases the mortality. Therefore, more effective biomarkers for early diagnosis of ESCC are necessary. Unfortunately, appropriate biomarkers for clinical diagnosis and prognosis have not been identified yet. However, recent progresses in quantitative proteomics have offered opportunities to identify plasma proteins as biomarkers for ESCC. In the present study, plasma samples were analyzed by differential in-gel electrophoresis (DIGE) and differentially expressed proteins were identified by matrix assisted laser desorption ionization-time of flight/time of flight mass spectrometry (MALDI-TOF/TOF MS). A total of 31 proteins representing 12 unique gene products were identified, in which 16 proteins were up-regulated and 15 down-regulated in tumors. The up-regulated proteins were alpha-2-HS-glycoprotein (AHSG), leucine-rich alpha-2-glycoprotein (LRG), zinc-alpha-2-glycoprotein, alpha-1-antichymotrypsin, complement factor I and complement C4-B, whereas the down-regulated proteins were serum albumin, Ig alpha-2 chain C region, alpha-1-antitrypsin, fibrinogen gamma chain, haptoglobin and hemoglobin subunit alpha. Among all the differentially expressed proteins, AHSG and LRG were validated by ELISA. The results were consistent with the data from the proteomics results, further suggesting that AHSG and LRG may be employed as potential biomarkers for the early diagnosis of ESCC. In summary, this study was the first time to use DIGE combined MALDI-TOF/TOF platform to identify the potential plasma biomarkers for ESCC. The plasma AHSG and LRG showed great potential for ESCC screening.

Expression of vascular endothelial growth factor (VEGF) and VEGF-C in serum and tissue of Wilms tumor.

BACKGROUND: Angiogenesis and lymphogenesis which were promoted by vascular endothelial growth factor (VEGF) and VEGF-C are important in the growth and metastasis of solid tumors. The high level of VEGF and VEGF-C were distributed in numerous types of cancers, but their distribution and expression in Wilms tumor, the most common pediatric tumor of the kidney, was unclear. METHODS: To learn about the distribution, mass spectroscopy and immunohistochemistry were used to measure the level of VEGF and VEGF-C in serum and tissue of Wilms tumor. RESULTS: The expression level of VEGF in serum of Wilms tumor was the same as in pre-surgery and control, so it was the same case of VEGF-C. Both of these factors were chiefly located in Wilms tumor tissue, but not in borderline and normal. In addition, the higher clinical staging and histopathologic grading were important elements in high expression of VEGF and VEGF-C. Gender, age and the size of tumor have not certainly been implicated in expression level of VEGF and VEGF-C. CONCLUSIONS: The lymph node metastasis and growth of tumors resulted from angiogenesis and lymphogenesis which were promoted by VEGF and VEGF-C in Wilms tumor. The autocrine and paracrine process of VEGF and VEGF-C were the principal contributor to specific tissues of Wilms tumor but not to the entire body.

On-line prediction of fresh pork quality using visible/near-infrared reflectance spectroscopy.

Visible/near-infrared (Vis/NIR) spectroscopy was tested to predict the quality attributes of fresh pork (content of intramuscular fat, protein and water, pH and shear force value) on-line. Vis/NIR spectra (350-1100 nm) were obtained from 211 samples using a prototype. Partial least-squares regression (PLSR) models were developed by external validation with wavelet de-noising and several pre-processing methods. The 6th order Daubechies wavelet with 6 decomposition levels (db6-6) showed high de-noising ability with good information preservation. The first derivative of db6-6 de-noised spectra combined with multiplicative scatter correction yielded the prediction models with the highest coefficient of determination (R(2)) for all traits in both calibration and validation periods, which were all above 0.757 except for the prediction of shear force value. The results indicate that Vis/NIR spectroscopy is a promising technique to roughly predict the quality attributes of intact fresh pork on-line.