Abstract: Objective　To analyze the nucleic acid detection results of severe acute respiratory syndrome corona virus-2 (SARS-CoV-2) by droplet digital PCR (ddPCR) and compare with the detection results of real-time fluorescence quantitative RT-PCR (qRT-PCR), so as to evaluate the advantages and disadvantages of detection, and to provide data support for optimizing the nucleic acid detection scheme of SARS-CoV-2. Methods　According to the SARS-CoV-2 specific primer probe published by the China Center for Disease Control and Prevention, a ddPCR detection method for SARS-CoV-2 was designed. One sample was selected for sensitivity test after gradient dilution; six respiratory virus nucleic acid positive samples including seasonal H3N2 influenza virus and SARS-CoV-2 positive samples were selected for specificity test; five SARS-CoV-2 positive samples were selected for repeatability test; in addition, 30 positive and 20 negative SARS-CoV-2 samples were selected for multiple clinical samples testing, and the results were analyzed and compared with those of qRT-PCR. Results　The ddPCR method can specifically detect SARS-CoV-2, and directly obtain the original copy number of the sample target gene to achieve accurate quantification; the sensitivity test of gradient dilution positive samples showed that qRT-PCR detected target genes in part of the 10-5 dilution of samples, and no target genes were detected in 10-6 dilution, while ddPCR detected all target genes in both 10-5 and 10-6 dilution of samples. The detection limit of ddPCR was two orders of magnitude higher than that of qRT-PCR, and the sensitivity was higher than that of qRT-PCR; in the comparison of the repeatability test results of the two methods, the coefficient of variation of ddPCR was 1.266%-11.814%, lower than 1.729%-26.174% of qRT PCR, and the repeatability was higher than qRT-PCR; among 50 clinical samples, 30 positive samples of confirmed cases of Coronavirus Disease 2019 (COVID-19) were detected by both methods, SARS-CoV-2 was successfully detected by both methods, and 20 negative samples of COVID-19 were detected by both methods, and the results were negative, with a coincidence rate of 100.00% (50/50). Conclusion　The ddPCR method can accurately quantify SARS-CoV-2 with strong specificity, and its sensitivity and repeatability are higher than those of qRT-PCR, but it also has certain detection limitations and is more suitable for the detection of low load samples. In the actual detection, the two methods can be reasonably combined to improve the detection accuracy.

The microarrays have revolutionised biomedical experimentation and diagnostics, enabling ordered high throughput analysis. During the past decade, classic solid phase substrates, such as microlitre plates, membrane filters and microscopic slides, were turn into high-density, chip-like structure. The concept of the arrayed library was central to this development which now extends from DNA to protein. The availability of such protein microarrays would facilitate the simultaneous analysis of thousands of interactions within a single experiment. They can be utilized for massively parallel testing of protein function or recognized their target polypeptide in complex biological solution. This article will focus on the current strategies used to generate protein microarray and their applications in biological research, medicine and diagnostics.
Biomedical Research ; Proteins ; analysis

OBJECTIVE: To examine the expression absence of LRRC4 gene in glioblastoma cell lines. METHODS: RT-PCR and Northern blot were used to detect the expression of LRRC4 gene in 6 glioblastomas cells lines. Polymerase chain reaction and DNA sequencing were used to screen the LRRC4 gene mutation, while bioinformation assay was used to search for the reason of LRRC4 gene absence in U251 cell lines. RESULTS: The expression of LRRC4 was absent in 6 malignant glioma cell lines (U251, U87, BT325, SF126, SF767 and M17), which were examined by Northern-blot and RT-PCR assay. All sequencing of PCR products from gDNA of SF126, SF767, and M17 cell lines contained the point mutation at the same position ( LRRC4 geneT977A) (3/5), which was a synonymous mutation. However, PCR products from gDNA of U251 and U87 cell lines (2/5) were not obtained. The expression absence of LRRC4 was ascribed to the loss of homozygosity of 7q32-ter in U251 cell lines. CONCLUSION The expression of LRRC4 gene is absent in glioblastoma cell lines, and it offers the important experiment proof for LRRC4 to act as a new candidate of brain tumor suppressor gene from glioma. The loss of homozygosity of 7q32-ter contributed to the expression absence of LRRC4 in U251 cell lines.
Base Sequence ; Blotting, Northern ; Brain Neoplasms ; genetics ; pathology ; Cell Line, Tumor ; DNA Mutational Analysis ; Gene Expression Regulation, Neoplastic ; Glioblastoma ; genetics ; pathology ; Humans ; Nerve Tissue Proteins ; genetics ; Point Mutation ; Reverse Transcriptase Polymerase Chain Reaction

OBJECTIVETo evaluate the validity and reliability of the Occupational Stress Scale (OSS) for Chinese offshore oil platform workers.

METHODSA 51-item self-administered questionnaire developed in the light of Cooper's questionnaire and company's special situation was used to investigate 561 subjects.

RESULTS51 occupational stress items relating to offshore oil production were subjected to factor analysis, and nine latent factors were identified, which explained 62.5% of the total variance. According to the contents described by the items included in each factor, they were respectively defined as: "the interface between job and family/social life (factor 1)", "career and achievement (factor 2)", "safety (factor 3)", "management problem and relationship with others at work (factor 4)", "physical factors of workplace (factor 5)", "platform living environment (factor 6)", "role in management (factor 7)", "ergonomics (factor 8)" and "organization structure (factor 9)". Significant difference in the score of five factors was observed among 12 different job categories by analysis of variance. After adjusting for potential confounding factors (age, educational level), hierarchical multiple regression analysis indicated that the score of the OSS was significantly and positively correlated with the poor mental health of the workers (P < 0.01). The consistent test between OSS and each factor showed that Cronbach's alpha were 0.72 - 0.91.

CONCLUSIONThe OSS is a valid and reliable tool for measuring occupational stress, and can be used to explore occupational stress and its influence on health and safety problems in offshore oil workers.

Adult ; Humans ; Middle Aged ; Occupational Diseases ; diagnosis ; Petroleum ; Stress, Psychological ; diagnosis

OBJECTIVETo investigate the risk factors for the development of congenital anal atresia in neonates.

METHODSA total of 70 neonates who were admitted to 17 hospitals in Foshan, China from January 2011 to December 2014 were enrolled as case group, and another 70 neonates who were hospitalized during the same period and had no anal atresia or other severe deformities were enrolled as control group. Univariate and multivariate logistic regression analyses were used to investigate the risk factors for the development of congenital anal atresia.

RESULTSThe univariate analysis revealed that the age of mothers, presence of oral administration of folic acid, infection during early pregnancy, and polyhydramnios, and sex of neonates showed significant differences between the case and control groups (P<0.05). The multivariate logistic regression analysis revealed that infection during early pregnancy (OR=18.776) and male neonates (OR=9.304) were risk factors for congenital anal atresia, and oral administration of folic acid during early pregnancy was the protective factor (OR=0.086).

CONCLUSIONSInfection during early pregnancy is the risk factor for congenital anal atresia, and male neonates are more likely to develop congenital anal atresia than female neonates. Supplementation of folic acid during early pregnancy can reduce the risk of congenital anal atresia.

Anus, Imperforate ; etiology ; Female ; Humans ; Infant, Newborn ; Logistic Models ; Male ; Pregnancy ; Risk Factors