SARS-CoV-2 with transcription regulatory sequence motif mutation poses a greater threat / 南方医科大学学报

OBJECTIVE@#To analyze the mutations in transcription regulatory sequences (TRSs) of coronaviruss (CoV) to provide the basis for exploring the patterns of SARS-CoV-2 transmission and outbreak.@*METHODS@#A combined evolutionary and molecular functional analysis of all sets of publicly available genomic data of viruses was performed.@*RESULTS@#A leader transcription regulatory sequence (TRS-L) usually comprises the first 60-70 nts of the 5' UTR in a CoV genome, and the body transcription regulatory sequences (TRS-Bs) are located immediately upstream of the genes other than ORF1a and 1b. In each CoV genome, the TRS-L and TRS-Bs share a specific consensus sequence, namely the TRS motif. Any changes of nucleotide residues in the TRS motifs are defined as TRS motif mutations. Mutations in the TRS-L or multiple TRS-Bs result in superattenuated variants. The spread of super-attenuated variants may cause an increase in asymptomatic or mild infections, prolonged incubation periods and a decreased detection rate of the viruses, thus posing new challenges to SARS-CoV-2 prevention and control. The super-attenuated variants also increase their possibility of long-term coexistence with humans. The Delta variant is significantly different from all the previous variants and may lead to a large-scale transmission. The Delta variant (B.1.617.2) with TRS motif mutation has already appeared and shown signs of spreading in Singapore, which, and even the Southeast Asia, may become the new epicenter of the next wave of SARS-CoV-2 outbreak.@*CONCLUSION@#TRS motif mutation will occur in all variants of SARS-CoV-2 and may result in super-attenuated variants. Only super-attenuated variants with TRS motif mutations will eventually lose the abilities of cross-species transmission and causing outbreaks.

Lumbar intervertebral disc degeneration assessed by the nine-point system with X-ray / 中国组织工程研究

BACKGROUND: The X-ray 9-point grading system is established based on cervical disc degeneration and its suitability for evaluation of lumbar disc degeneration has not been validated. OBJECTIVE: To investigate the feasibility of the evaluation of lumbar intervertebral disc degeneration using the 9-point grading system with X-ray, and to explore its clinical application value. METHODS: The correlation between 9-point grading system and Pfirrmann system was statistically analyzed. Magnetic resonance imaging (MRI) and X-ray images of 172 cases with lumbar disc degeneration or simple lumbago, who were treated in the Shanghai Changzheng Hospital from June 2013 to June 2016, were retrospectively analyzed. The MRI scores of lumbar disc degeneration were evaluated according to Pfirrmann standard, and the X-ray scores were evaluated according to 9-point grading system. The two groups of scores were respectively analyzed by the correlation and regression tests via Spearman rank sum test with SPSS software. RESULTS AND CONCLUSION: (1) MRI scores (the independent variable X): 2 cases scored 1; 8 cases scored 2; 55 cases scored 3; 84 cases scored 4; 23 cases scored 5. X-ray scores (the dependent variable Y): 2 cases scored 0; 6 cases scored 1; 21 cases scored 2; 43 cases scored 3; 40 cases scored 4; 26 cases scored 5; 16 cases scored 6; 8 cases scored 7; 7 cases scored 8; 3 cases scored 9. (2) The Spearman correlation test showed that significant positive correlation was found between Pfirrmann system and 9-point grading system (P <0.01). Significance test of correlation coefficient proved that there was significant linear correlation between Pfirrmann system and 9-point grading system. Further regression analysis showed the linear regression between Pfirrmann system and 9-point grading system. (3) These findings suggested that Pfirrmann system and X-ray 9-point grading system had a good consistency in evaluating lumbar disc degeneration. As a scientific, fast and effective evaluation method, the X-ray 9-point grading system has a certain reference value in the diagnoses of lumbar degenerative diseases.

Preparation and evaluation of a new xenogenic implant material / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare a new xenogenic material using patented biochemical techniques for tissue disposal and investigate its possibility to be used as implant materials.</p><p><b>METHODS</b>The xenogenic implant materials were prepared by treatment of fresh porcine tendon with epoxy cross-linking fixation, antigen minimization procedures, mechanical enhancement by protein molecule modification and surface treatments. Histological and scanning electron microscopic observations were conducted, and physicochemical property assessment was carried out to determine the mechanical properties, protein contents, polyepoxy compound residual and stability of the material. The in vitro cytotoxicity of the material was tested in NCTC L929 cells, and the optical density of the cells at 24, 48, and 72 h of the treatments was determined to calculate the relative growth rate (RGR).</p><p><b>RESULTS</b>Histological observation suggested that the xenogenic implant material consisted primarily of collagen without cell fragments. Scanning electron microscopy demonstrated homogeneous alignment of the collagen fibers in the material. The tensile strength of the material was 11-16 MPa, and the breaking elongation rate was 52%-67%; the protein contents was 94% with polyepoxy compound residual less than 5 microg/ml. The material maintained stable pH value in PBS. The L929 cells incubated with the biomaterials grew well with a relative growth rate over 89%.</p><p><b>CONCLUSION</b>The new biomaterial has good physicochemical properties and good biocompatibility, and may served as a promising implant material.</p>

A novel method for detecting single-nucleotide polymorphisms by using ShineRoar probes / 中华检验医学杂志

Objective The present study demonstrates a novel,simple and cost-effective method for detecting known SNP genotyping by using ShineRoar probes.Methods The SNP of target genes detected by using the ShineRoar probes and melting curve analysis.Tumor necrosis factor receptor Ⅱ (TNFR Ⅱ) and apolipoprotein M (apoM) had been employed as target genes to describe the method in details.The PCR products of TNFR Ⅱ and apoM were collected and sequenced.Results The melting temperatures (TM) were significantly different between mutated genotypes and wild-type genotype.A biallelic SNP marker (T/ G) at position 196 in exon 6 of TNFR Ⅱ gene showed two melting valleys with the appropriate TMs at (52.84?0.75)℃ and (58.38?0.61)℃,respectively.For apoM T-778C,TMs of homozygous T genotype and C genotype were (42.55?0.73)℃ and (49.19?0.57)℃,respectively.Moreover,this genotyping method was validated by the DNA sequence analyses (Kappa=1,P=0.000).Conclusion It is concluded that this novel method is simple and economical and it is suitable for a large-scale genotyping screening.