CRISPR-Cas12a-Empowered Electrochemical Biosensor for Rapid and Ultrasensitive Detection of SARS-CoV-2 Delta Variant

Coronavirus disease 2019 (COVID-19) is a highly contagious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The gold standard method for the diagnosis of SARS-CoV-2 depends on quantitative reverse transcription-polymerase chain reaction till now, which is time-consuming and requires expensive instrumentation, and the confirmation of variants relies on further sequencing techniques. Herein, we first proposed a robust technique-methodology of electrochemical CRISPR sensing with the advantages of rapid, highly sensitivity and specificity for the detection of SARS-CoV-2 variant. To enhance the sensing capability, gold electrodes are uniformly decorated with electro-deposited gold nanoparticles. Using DNA template identical to SARS-CoV-2 Delta spike gene sequence as model, our biosensor exhibits excellent analytical detection limit (50 fM) and high linearity (R² = 0.987) over six orders of magnitude dynamic range from 100 fM to 10 nM without any nucleic-acid-amplification assays. The detection can be completed within 1 h with high stability and specificity which benefits from the CRISPR-Cas system. Furthermore, based on the wireless micro-electrochemical platform, the proposed biosensor reveals promising application ability in point-of-care testing.

Susceptibility-weighted imaging cannot distinguish radionecrosis from recurrence in brain metastases after radiotherapy: a comparison with high-grade gliomas

AIM

To explore the efficiency of susceptibility-weighted imaging (SWI) in the differential diagnosis of recurrence from radionecrosis in brain metastases (BM) and in high-grade gliomas (HGG).

MATERIALS AND METHODS

From September 2016 to November 2018, 56 patients with BM and 42 patients with HGG were included in this retrospective study. BM and HGG were assigned to the recurrence and radionecrosis groups according to their histopathology or follow-up results. The proportion of dark signal intensity (proDSI), which was defined as the area of dark signal on SWI or the enhancing area on contrast-enhanced T1-weighted imaging (T1WI), was calculated for each patient. Analysis of variance (ANOVA) with Tukey's honestly significant difference test was used for the repeat multiple comparisons. Receiver operating characteristic curve analysis was performed to validate the diagnostic performance.

RESULTS

For HGG, the proDSI in the recurrence group was significantly lower than that in the radionecrosis group (0.13 ± 0.05 versus 0.43 ± 0.11, p<0.001); however, for BM, no statistical difference was found between groups (0.49 ± 0.09 versus 0.46 ± 0.08, p=0.26). proDSI had the best diagnostic performance (AUC = 0.87, 95% CI: 0.76-0.98; sensitivity = 0.87; specificity = 0.88) for HGG, when a cut-off value of 0.21 was selected.

CONCLUSIONS

Semi-quantitative analysis using SWI is feasible for the differential diagnosis between recurrence and radionecrosis in HGG, but is not feasible in BM. Semi-quantitative assessment based on SWI should interpreted with caution in BM after radiotherapy in clinical practice.

A CRISPR/Cas12a empowered surface plasmon resonance platform for rapid and specific diagnosis of the Omicron variant of SARS-CoV-2

The outbreak of the COVID-19 pandemic was partially due to the challenge of identifying asymptomatic and presymptomatic carriers of the virus, and thus highlights a strong motivation for diagnostics with high sensitivity that can be rapidly deployed. On the other hand, several concerning SARS-CoV-2 variants, including Omicron, are required to be identified as soon as the samples are identified as ‘positive’. Unfortunately, a traditional PCR test does not allow their specific identification. Herein, for the first time, we have developed MOPCS (Methodologies of Photonic CRISPR Sensing), which combines an optical sensing technology-surface plasmon resonance (SPR) with the ‘gene scissors’ clustered regularly interspaced short palindromic repeat (CRISPR) technique to achieve both high sensitivity and specificity when it comes to measurement of viral variants. MOPCS is a low-cost, CRISPR/Cas12a-system-empowered SPR gene-detecting platform that can analyze viral RNA, without the need for amplification, within 38 min from sample input to results output, and achieve a limit of detection of 15 fM. MOPCS achieves a highly sensitive analysis of SARS-CoV-2, and mutations appear in variants B.1.617.2 (Delta), B.1.1.529 (Omicron) and BA.1 (a subtype of Omicron). This platform was also used to analyze some recently collected patient samples from a local outbreak in China, identified by the Centers for Disease Control and Prevention. This innovative CRISPR-empowered SPR platform will further contribute to the fast, sensitive and accurate detection of target nucleic acid sequences with single-base mutations.

[Application of three-dimensional visualization technique in laparoscopic D3 radical resection of right colon cancer]

OBJECTIVE

To explore the clinical value of three-dimensional (3D) visualization technique in laparoscopic D3 radical resection of right colon cancer.

METHODS

We retrospectively analyzed the clinical data of 73 patients with right colon cancer undergoing laparoscopic D3 radical operation in our hospital between May, 2019 and March, 2021. Among these patients, 41 underwent enhanced CT examination with 3D visualization reconstruction to guide the actual operation, and 32 underwent enhanced CT examination only before the operation (control group). In 3D visualization group, we examined the coincidence rate between the 3D visualization model and the findings in surgical exploration of the anatomy and variations of the main blood vessels, supplying vessels of the tumor, and the tumor location, and the coincidence rate between the actual surgical plan for D3 radical resection of right colon cancer and the plan formulated based on the 3D model. The operative time, estimated blood loss, unexpected injury of blood vessels, number of harvested lymph nodes, mean time of the first flatus, complications, postoperative hospital stay and postoperative drainage volume were compared between the two groups.

RESULTS

The operative time was significantly shorter in 3D visualization group than in the control group (P < 0.05). The volume of blood loss, proportion of unexpected injury of blood vessel, the number of harvested lymph nodes, time of the first flatus, proportion of complications, postoperative hospital stay and postoperative drainage volume did not differ significantly between the two groups (P > 0.05). In the 3D visualization group, the 3D visualization model clearly displayed the shape and direction of the colon, the location of the tumor, the anatomy and variation of the main blood vessels and the blood vessels supplying the cancer, and showed a coincidence rate of 100% with the findings by surgical exploration. The surgical plan for D3 radical resection of right colon cancer was formulated based on the 3D model also showed a coincidence rate of 100% with the actual surgical plan.

CONCLUSION

The 3D visualization reconstruction technique allows clear visualization the supplying arteries of the tumor and their variations to improve the efficiency, safety and accuracy of laparoscopic D3 radical resection of right colon cancer.

[Comparison of the long-term outcomes of focused ultrasound ablation surgery for uterine fibroids and myomectomy]

Objective: To compare the long-term outcomes after focused ultrasound ablation surgery (FUAS) versus myomectomy for uterine fibroids. Methods: A retrospective study was conducted on women who were treated by FUAS or myomectomy for uterine fibroids at First Medical Center of Chinese PLA General Hospital from January 2007 to January 2015. Regular follow-up was conducted to evaluate the symptoms relief, symptoms recurrence, the need for re-interventions and complications of the two groups. Results: The effective rates were 95.7% (730/763) and 95.5% (1 151/1 205) in women who were treated by FUAS and myomectomy, no statistical difference was seen between the two groups (χ²=0.027, P=0.869). The cumulative rates of symptoms recurrence at 1 year, 3 years, 5 years, 8 years and 10 years of follow-up in FUAS group were 1.8%, 6.8%, 11.9%, 15.2% and 15.9%, respectively; and the cumulative re-intervention rates were 0.7%, 4.1%, 6.8%, 9.9% and 11.0%, respectively. The cumulative rates of symptoms recurrence at 1 year, 3 years, 5 years, 8 years and 10 years of follow-up in myomectomy group were 1.8%, 5.9%, 10.6%, 14.2% and 14.9%, respectively; and the cumulative re-intervention rates were 0.9%, 4.5%, 7.8%, 10.3% and 11.4%, respectively. No statistical differences were seen between the two groups (all P>0.05). There were no significant differences in the effective rate, symptoms recurrence rate and re-intervention rate between the two groups in patients with intermural fibroids; but the effective rate of FUAS (95.9%, 235/245) was higher than that of myomectomy (89.1%, 115/129), the symptoms recurrence rate (11.9%, 28/235) was lower than that of myomectomy (27.8%, 32/115), and the re-intervention rate (7.7%, 18/235) was lower than that of myomectomy (17.4%, 20/115) in patients with submucosal fibroids, there were significant different (all P<0.05). The effective rate of FUAS (91.0%, 132/145) was lower than that of myomectomy (97.0%, 322/332), the symptoms recurrence rate (32.6%, 43/132) was higher than that of myomectomy (9.9%, 32/322), and the re-intervention rate (22.0%, 29/132) was higher than that of myomectomy group (6.2%, 20/132) in patients with subserosal fibroids, there were significant different (all P<0.01). The incidences of total [1.8% (14/763) vs 21.9% (264/1 205)], minor and moderate adverse events were lower in FUAS group than myomectomy group (all P<0.001). Conclusion: Satisfaction with long-term outcomes after FUAS treatment or myomectomy for uterine fibroids is comparable.

[Progress on clinical trials of common gastrointestinal cancer drugs in China from 2012 to 2021]

Objective: Systematically summarize the research progress of clinical trials of gastric cancer oncology drugs and the overview of marketed drugs in China from 2012 to 2021, providing data and decision-making evidence for relevant departments. Methods: Based on the registration database of the drug clinical trial registration and information disclosure platform of Food and Drug Administration of China and the data query system of domestic and imported drugs, the information on gastric cancer drug clinical trials, investigational drugs and marketed drugs from January 1, 2012 to December 31, 2021 was analyzed, and the differences between Chinese and foreign enterprises in terms of trial scope, trial phase, treatment lines and drug type, effect and mechanism studies were compared. Results: A total of 114 drug clinical trials related to gastric tumor were registered in China from 2012 to 2021, accounting for 3.7% (114/3 041) of all anticancer drug clinical trials in the same period, the registration number showed a significant growth rate after 2016 and reached its peak with 32 trials in 2020. Among them, 85 (74.6%, 85/114) trials were initiated by Chinese pharmaceutical enterprise. Compared with foreign pharmaceutical enterprise, Chinese pharmaceutical enterprise had higher rates of phase I trials (35.3% vs 6.9%, P=0.001), but the rate of international multicenter trials (11.9% vs 67.9%, P<0.001) was relatively low. There were 76 different drugs involved in relevant clinical trials, of which 65 (85.5%) were targeted drugs. For targeted drugs, HER2 is the most common one (14 types), followed by PD-1 and multi-target VEGER. In the past ten years, 3 of 4 marketed drugs for gastric cancer treatment were domestic and included in the national medical insurance directory. Conclusions: From 2012 to 2021, China has made some progress in drug research and development for gastric carcinoma. However, compared with the serious disease burden, it is still insufficient. Targeted strengthening of research and development of investment in many aspects of gastric cancer drugs, such as new target discovery, matured target excavating, combination drug development and early line therapy promotion, is the key work in the future, especially for domestic companies.

[Stereotactic body radiation therapy for patients with lung and liver oligometastases from colorectal cancer: a phase Ⅱ trial]

Objective: To explore the safety and effectiveness of stereotactic body radiation therapy (SBRT) for oligometastases from colorectal cancer (CRC). Methods: This is a prospective, single-arm phase Ⅱ trial. Patients who had histologically proven CRC, 1 to 5 detectable liver or lung metastatic lesions with maximum diameter of any metastases ≤5 cm were eligible. SBRT was delivered to all lesions. The primary endpoint was 3-year local control (LC). The secondary endpoints were treatment-related acute toxicities of grade 3 and above, 1-year and 3-year overall survival (OS) and progression free survival (PFS). Survival analysis was performed using the Kaplan-Meier method and Log rank test. Results: Petients from 2016 to 2019 who were treated in Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College. Forty-eight patients with 60 lesions were enrolled, including 37 liver lesions and 23 lung lesions. Forty-six patients had 1 or 2 lesions, with median diameter of 1.3 cm, the median biologically effective dose (BED(10)) was 100.0 Gy. The median follow-up was 19.5 months for all lesions. Twenty-five lesions developed local failure, the median local progression free survival was 15 months. The 1-year LC, OS and PFS was 70.2% (95% CI, 63.7%~76.7%), 89.0% (95% CI, 84.3%~93.7%) and 40.4% (95%CI, 33.0%~47.8%). The univariate analysis revealed that planning target volume (PTV) and total dose were independent prognostic factors of LC (P<0.05). For liver and lung lesions, the 1-year LC, OS and PFS was 58.7% and 89.4% (P=0.015), 89.3% and 86.5% (P=0.732), 30.5% and 65.6% (P=0.024), respectively. No patients developed acute toxicity of grade 3 and above. Conclusion: SBRT is safe and effective treatment method for oligometastases from CRC under precise respiratory motion management and robust quality assurance.

Protective effect of lithium chloride on pulmonary injury caused by Actinobacillus pleuropneumoniae via inhibition of GSK-3β-NF-κB-dependent pathway

Porcine contagious pleuropneumonia (PCP) is a very serious respiratory disease which is difficult to prevent and treat. In this study, the therapeutic effects of lithium chloride (LiCl) on PCP were examined using a mouse model. A mouse model of PCP was established by intranasal infections with Actinobacillus pleuropneumoniae (App). Histopathological analysis was performed by routine paraffin sections and an H-E staining method. The inflammatory factors, TLR4 and CCL2 were analyzed by qPCR. The expression levels of p-p65 and pGSK-3ß were detected using the Western Blot Method. The death rates, clinical symptoms, lung injuries, and levels of TLR-4, IL-1ß, IL-6, TNF-α, and CCL2 were observed to decrease in the App-infected mice treated with LiCl. It was determined that the LiCl treatments had significantly reduced the mortality of the App-infected cells, as well as the expressions of p-p65 and pGSK-3ß. The results of this study indicated that LiCl could improve the pulmonary injuries of mice caused by App via the inhibition of the GSK-3β-NF-κB-dependent pathways, and may potentially become an effective drug for improving pulmonary injuries caused by PCP.

Development of an indirect enzyme-linked immunosorbent assay for the detection of novel chicken orthoreovirus

A novel avian orthoreovirus (N-ARV) variant characterized with obvious arthritis and synovial inflammation, was isolated from Shandong, China in May 2016. It caused chicken poor growth and enormous economic losses to the poultry industry of China. However, there are few effective methods for detecting the antibody levels of N-ARV. In this study, a viral structural protein σC was expressed using the prokaryotic expression vector pET32a (+). The target protein was obtained by inducing for 6 hours at an IPTG concentration of 0.6mM. The optimal dilution of the coating antigen and serum antibody were determined to be 1000 fold and 10 fold respectively. A specificity test showed that there was no positive reactivity between N-ARV and other pathogens, and when the positive serum was diluted 100 times detection results were still checkable. The repeatability of this method was determined by the inter assay and intra assay tests with variability ranging from 4.85% to 7.93%. In conclusion, this indirect enzyme linked immunosorbent assay (ELISA) will be useful for large-scale serological surveys and monitoring antibody levels in N-ARV infection.

[Changes in the structure of intestinal mucosal flora in colorectal cancer patients]

OBJECTIVE

To investigate the changes in bacterial flora in fecal samples, at the tumor loci and in adjacent mucosa in patients with colorectal cancer (CRC).

METHODS

We collected fecal samples from 13 patients with CRC and 20 healthy individuals and tumor and adjacent mucosa samples from 6 CRC patients. The differences in bacterial composition between the fecal and mucosa samples were analyzed with 16S rDNA sequencing and bioinformatics methods. We also detected the total number of bacteria in the feces using flow cytometry, isolated and identified the microorganisms in the fecal and mucosa samples using common bacterial culture media. We further tested the effects of 7 isolated bacterial strains on apoptosis of 3 CRC cell lines using lactate dehydrogenase detection kit.

RESULTS

The bacterial α-diversity in the feces of healthy individuals and in adjacent mucosa of CRC patients was significantly higher than that in the feces and tumor mucosa in CRC patients (P < 0.05). Lactobacillaceae is a specific bacteria in the feces, while Escherichia, Enterococcus, and Fusobacterium are specific bacteria in tumor mucosa of CRC patients as compared with healthy individuals. Cell experiment with3 CRC cell lines showed that Bacteroides fragilis isolated from the tumor mucosa of CRC patients produced significant inhibitory effects on cell proliferation (P < 0.0001), while the isolated strain Fusobacterium nucleatum obviously promoted the proliferation of the cell lines (P < 0.001).

CONCLUSION

The bacterial flora in the feces, tumor mucosa and adjacent mucosa of CRC patients is significantly different from that in the feces of healthy individuals, and the fecal flora of CRC patients can not represent the specific flora of the tumor mucosa. Inhibition of F. nucleatum colonization in the tumor mucosa and promoting B. fragilis colonization may prove beneficial for CRC treatment.

A mathematical model of COVID-19 transmission

Disease transmission is studied through disciplines like epidemiology, applied mathematics, and statistics. Mathematical simulation models for transmission have implications in solving public and personal health challenges. The SIR model uses a compartmental approach including dynamic and nonlinear behavior of transmission through three factors: susceptible, infected, and removed (recovered and deceased) individuals. Using the Lambert W Function, we propose a framework to study solutions of the SIR model. This demonstrates the applications of COVID-19 transmission data to model the spread of a real-world disease. Different models of disease including the SIR, SIRmp and SEIRρqr model are compared with respect to their ability to predict disease spread. Physical distancing impacts and personal protection equipment use are discussed with relevance to the COVID-19 spread.

The expression profile of miR-222b-5p/MAPK10 in spleens of SPF chickens infected with REV-SNV at 28-42 dpi

Reticuloendotheliosis virus (REV) is an avian oncogenic retrovirus that causes atrophy of immune organs, such as the spleen, thymus, and bursa of Fabricius, leading to severe immunosuppression. However, there is limited information describing the genes or microRNAs (miRNAs) that play a role in replicating REV-spleen necrosis virus (SNV). Our previous miRNA and RNA sequencing data showed that the expression of gga-miR-222b-5p was significantly upregulated in REV-SNV-infected chicken spleens of 7, 14, and 21 dpi compared to non-infected chicken spleens, but mitogen-activated protein kinase 10 (MAPK10), which is related to innate immunity, had the opposite expression pattern. To understand chicken cellular miRNA function in the virus-host interactions during REV infection, we used quantitative reverse transcription PCR (qRT-PCR) to determine whether the expression of gga-miR-222b-5p and MAPK10 in the spleen of specific-pathogen-free chickens at 28, 35, and 42 dpi was consistent with the first 3 time points, and dual-luciferase reporter assay was used to determine the targeting relationship between gga-miR-222b-5p and MAPK10. Results show that MAPK10 was downregulated at all 3 time points; however, significant difference (p⟨0.01) was noted only at 35 dpi. Moreover, the expression of gga-miR-222b-5p was upregulated; however, significant difference (p⟨0.01) was observed only at 28 and 35 dpi. A dual-luciferase reporter assay showed that MAPK10 is a direct target of gga-miR-222b-5p. This study suggests that gga-miR-222b-5p may target MAPK10 to promote the REV-SNV-induced tumorigenesis via the RLRs signaling pathway.