Single chain antibody fragment display systems: a review / 生物工程学报

Single chain antibody fragment (scFv) is a small molecule composed of a variable region of heavy chain (VH) and a variable region of light chain (VL) of an antibody, and these two chains are connected by a flexible short peptide. scFv is the smallest functional fragment with complete antigen-binding activity, which contains both the antibody-recognizing site and the antigen-binding site. Compared with other antibodies, scFv has the advantages of small molecular weight, strong penetration, low immunogenicity, and easy expression. Currently, the most commonly used display systems for scFv mainly include the phage display system, ribosome display system, mRNA display system, yeast cell surface display system and mammalian cell display system. In recent years, with the development of scFv in the field of medicine, biology, and food safety, they have also attracted much attention in the sectors of biosynthesis and applied research. This review summarizes the advances of scFv display systems in recent years in order to facilitate scFv screening and application.

Research on the correlation between the preference of personalized learning resource recommendation system and self-directed learning level of medical students / 中华医学教育探索杂志

Objective:To understand the preferences of medical students for the performance, function and recommendation method of personalized learning resource recommendation system, as well as the correlation with the self-directed learning ability of medical students, so as to provide a reference for further building an effective learning platform and learning resource tool.Methods:A total of 482 first-year to third-year medical students in a medical university were selected as the research subjects. The electronic self-directed learning scale and the self-designed medical education learning resources recommendation system of performance, function and recommendation method scale were used to conduct a questionnaire survey. Pearson correlation analysis was used to explore the correlation between the performance, function and recommendation method preference of medical students' information resource recommendation system and self-directed learning ability.Results:Medical students had high demand and preference for learning [(4.35±0.58) points], accuracy [(4.32±0.62) points] and timeliness [(4.32±0.62) points] of learning resource recommendation system. In terms of the function of the recommendation system, the following [(4.10±0.71) points] and sharing [(3.94±0.82) points], and searching [(4.35±0.59) points], feedback [(4.09±0.73) points] and publication [(3.80±0.88) points] in the interactive function were all highly rated. For the preference of recommendation methods, the scores of discipline connection [(4.07±0.66) points] and time line [(4.02±0.74) points] were higher. The dimensions with high relevance to self-directed learning included timeliness ( r=0.367), social attributes ( r=0.361), and the basis of similar groups ( r=0.316). Conclusion:Medical students are familiar with and have a positive attitude towards the performance, functions and recommendation methods of the learning resource recommendation system, and have a cognitive foundation for the construction of the learning resource recommendation system and related resource platforms. This system has a certain correlation with the self-directed learning ability of medical students. Promoting the construction of medical education information resources is conducive to promoting the development of self-directed learning ability of medical students.

Gut microbiota dysbiosis is associated with altered tryptophan metabolism and dysregulated inflammatory response in severe COVID-19

The clinical course of the 2019 coronavirus disease (COVID-19) is variable and to a substantial degree still unpredictable, especially in persons who have neither been vaccinated nor recovered from previous infection. We hypothesized that disease progression and inflammatory responses were associated with alterations in the microbiome and metabolome. To test this, we integrated metagenome, metabolome, cytokine, and transcriptome profiles of longitudinally collected samples from hospitalized COVID-19 patients at the beginning of the pandemic (before vaccines or variants of concern) and non-infected controls, and leveraged detailed clinical information and post-hoc confounder analysis to identify robust within- and cross-omics associations. Severe COVID-19 was directly associated with a depletion of potentially beneficial intestinal microbes mainly belonging to Clostridiales, whereas oropharyngeal microbiota disturbance appeared to be mainly driven by antibiotic use. COVID-19 severity was also associated with enhanced plasma concentrations of kynurenine, and reduced levels of various other tryptophan metabolites, lysophosphatidylcholines, and secondary bile acids. Decreased abundance of Clostridiales potentially mediated the observed reduction in 5-hydroxytryptophan levels. Moreover, altered plasma levels of various tryptophan metabolites and lower abundances of Clostridiales explained significant increases in the production of IL-6, IFN{gamma} and/or TNF. Collectively, our study identifies correlated microbiome and metabolome alterations as a potential contributor to inflammatory dysregulation in severe COVID-19. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=150 HEIGHT=200 SRC="FIGDIR/small/518860v1_ufig1.gif" ALT="Figure 1"> View larger version (48K): org.highwire.dtl.DTLVardef@de2c31org.highwire.dtl.DTLVardef@27663corg.highwire.dtl.DTLVardef@a90af7org.highwire.dtl.DTLVardef@f17e9_HPS_FORMAT_FIGEXP M_FIG C_FIG

Finite Element Analysis and in vitro Hemodynamic Testing of Polyester Textile Valves with Nitinol Wires / 医用生物力学

Objective To study mechanical properties of polyethylene terephthalate (PET)-based textile valves woven with nickel-titanium (NiTi) wires by finite element method, and combined with in vitro hemodynamic testing, to analyze the effect of wire quantity and woven position on hemodynamic performance of PET textile valve. Methods The three-dimensional (3D) geometric models of PET valves without wires and models of PET valves with wires by different numbers and distributions in radial direction were constructed using modeling software. Material properties of PET valves and wires were given based on the literature and experimental data. The transvalvular pressure difference curves of PET valves obtained from in vitro pulsatile flow experiments were used as boundary conditions. Stress distributions of the valve during peak systole and diastole were studied by finite element analysis software. Hydrodynamic performance of the valve with wires was evaluated by in vitro pulsatile flow experiments. ResultsThe finite element analysis results showed that the radially woven NiTi wires could enhance support for the PET textile valve, and support force and area of the valve in belly region of the valve leaflet with evenly distributed metal wires increased with the number of metal wires. The situation of support force was similar for silk distributions on both sides of the belly. The weaving of wires reduced stress concentration on the PET textile valve to a certain extent. The pulsatile flow experiment results showed that the stability of opening and closing shapes, effective opening area (EOA), regurgitation fraction (RF) and transvalvular pressure differences for two kinds of the PET valves with woven wires were better than those of the PET valves without wires. Conclusions Weaving metal wires in radial direction of the PET textile valve can effectively reduce stress concentrations on the PET textile valve during the cardiac cycle, and reduce tearing possibility of the valve leaflet. The woven metal wires can improve opening and closing stability of PET textile valve in in vitro hydrodynamic test, increase EOA and reduce RF and transvalvular pressure difference of the PET valve.

Assessment of twenty-two SARS-CoV-2 rapid antigen tests against SARS-CoV-2: A laboratory evaluation study

BackgroundRapid antigen testing is widely used as a way of scaling up population-level testing. To better inform antigen test deployment in Australia, we evaluated 22 commercially available antigen tests against the currently circulating delta variant, including an assessment of culture infectivity. MethodsAnalytical sensitivity was evaluated against SARS-CoV-2 B.1.617.2 (Delta), reported as TCID50/mL, cycle threshold (Ct) and viral load (RNA copies/mL). Specificity was assessed against non-SARS-CoV-2 viruses. Clinical sensitivity and correlation with cell culture infectivity was assessed using the Abbott PanBio COVID-19 Ag test. ResultsNineteen kits consistently detected SARS-CoV-2 antigen equivalent to 1.3 x 106 copies/mL (5.8 x 103 TCID50 /mL). Specificity for all kits was 100%. Compared to RT-PCR the Abbott PanBio COVID-19 Ag test was 52.6% (95% CI, 41.6% to 63.3%) concordant, with a 50% detection probability for infectious cell culture at 5.9 log10 RNA copies/mL (95% CI, 5.3 to 6.5 log10 copies/mL). Antigen test concordance was 97.6% (95% CI, 86.3% to 100.0%) compared to cell culture positivity. ConclusionsAntigen test positivity correlated with positive viral culture, suggesting antigen test results may determine SARS-CoV-2 transmission risk. Analytical sensitivity varied considerably between kits highlighting the need for ongoing systematic post-market evaluation to inform test selection and deployment.

Induction of trained immunity by influenza vaccination - impact on COVID-19

Non-specific protective effects of certain vaccines have been reported, and long-term boosting of innate immunity, termed trained immunity, has been proposed as one of the mechanisms mediating these effects. Several epidemiological studies suggested cross-protection between influenza vaccination and COVID-19. In a large academic Dutch hospital, we found that SARS-CoV-2 infection was less common among employees who had received a previous influenza vaccination: relative risk reductions of 37% and 49% were observed following influenza vaccination during the first and second COVID-19 waves, respectively. The quadrivalent inactivated influenza vaccine induced a trained immunity program that boosted innate immune responses against various viral stimuli and fine-tuned the anti-SARS-CoV-2 response, which may result in better protection against COVID-19. Influenza vaccination led to transcriptional reprogramming of monocytes and reduced systemic inflammation. These epidemiological and immunological data argue for potential benefits of influenza vaccination against COVID-19, and future randomized trials are warranted to test this possibility.

Gray Matter Abnormalities of Orbitofrontal Cortex and Striatum in Drug-Naïve Adult Patients With Obsessive-Compulsive Disorder.

Objective: This study examined whether obsessive-compulsive disorder (OCD) patients have gray matter abnormalities in regions related to executive function, and whether such abnormalities are associated with impaired executive function. Methods: Multiple scales were administered to 27 first-episode drug-naïve OCD patients and 29 healthy controls. Comprehensive brain morphometric indicators of orbitofrontal cortex (OFC) and three striatum areas (caudate, putamen, and pallidum) were determined. Hemisphere lateralization index was calculated for each region of interest. Correlations between lateralization index and psychological variables were examined in OCD group. Results: The OCD group had greater local gyrification index for the right OFC and greater gray matter volumes of the bilateral putamen and left pallidum than healthy controls. They also had weaker left hemisphere superiority for local gyrification index of the OFC and gray matter volume of the putamen, but stronger left hemisphere superiority for gray matter volume of the pallidum. Patients' lateralization index for local gyrification index of the OFC correlated negatively with Yale-Brown Obsessive Compulsive Scale and Dysexecutive Questionnaire scores, respectively. Conclusion: Structural abnormalities of the bilateral putamen, left pallidum, and right OFC may underlie OCD pathology. Abnormal lateralization in OCD may contribute to the onset of obsessive-compulsive symptoms and impaired executive function.

Long non-coding RNA SAP30-2:1 is downregulated in congenital heart disease and regulates cell proliferation by targeting HAND2 / 医学前沿

Congenital heart disease (CHD) is the most common birth defect worldwide. Long non-coding RNAs (lncRNAs) have been implicated in many diseases. However, their involvement in CHD is not well understood. This study aimed to investigate the role of dysregulated lncRNAs in CHD. We used Gene Expression Omnibus data mining, bioinformatics analysis, and analysis of clinical tissue samples and observed that the novel lncRNA SAP30-2:1 with unknown function was significantly downregulated in damaged cardiac tissues from patients with CHD. Knockdown of lncRNA SAP30-2:1 inhibited the proliferation of human embryonic kidney and AC16 cells and decreased the expression of heart and neural crest derivatives expressed 2 (HAND2). Moreover, lncRNA SAP30-2:1 was associated with HAND2 by RNA immunoprecipitation. Overall, these results suggest that lncRNA SAP30-2:1 may be involved in heart development through affecting cell proliferation via targeting HAND2 and may thus represent a novel therapeutic target for CHD.

A functional genomics approach to understand host genetic regulation ofCOVID-19 severity

Recent genome-wide association studies (GWASs) of COVID-19 patients of European ancestry have identified genetic loci significantly associated with disease severity (1). Here, we employed the detailed clinical, immunological and multi-omics dataset of the Human Functional Genomics Projects (HFGP) to explore the physiological significance of the host genetic variants that influence susceptibility to severe COVID-19. A genomics investigation intersected with functional characterization of individuals with high genetic risk for severe COVID-19 susceptibility identified several major patterns: i. a large impact of genetically determined innate immune responses in COVID-19, with increased susceptibility for severe disease in individuals with defective monocyte-derived cytokine production; ii. genetic susceptibility related to ABO blood groups is probably mediated through the von Willebrand factor (VWF) and endothelial dysfunction. We further validated these identified associations at transcript and protein levels by using independent disease cohorts. These insights allow a physiological understanding of genetic susceptibility to severe COVID-19, and indicate pathways that could be targeted for prevention and therapy. One Sentence summaryIn this study, we explore the physiological significance of the genetic variants associated with COVID-19 severity using detailed clinical, immunological and multi-omics data from large cohorts. Our findings allow a physiological understanding of genetic susceptibility to severe COVID-19, and indicate pathways that could be targeted for prevention and therapy.

Suppressive myeloid cells are a hallmark of severe COVID-19

Severe Acute Respiratory Syndrome - Coronavirus-2 (SARS-CoV-2) infection causes Coronavirus Disease 2019 (COVID-19), a mild to moderate respiratory tract infection in the majority of patients. A subset of patients, however, progresses to severe disease and respiratory failure with acute respiratory distress syndrome (ARDS). Severe COVID-19 has been associated with increased neutrophil counts and dysregulated immune responses. The mechanisms of protective immunity in mild forms and the pathogenesis of dysregulated inflammation in severe courses of COVID-19 remain largely unclear. Here, we combined two single-cell RNA-sequencing technologies and single-cell proteomics in whole blood and peripheral blood mononuclear cells (PBMC) to determine changes in immune cell composition and activation in two independent dual-center patient cohorts (n=46+n=54 COVID-19 samples), each with mild and severe cases of COVID-19. We observed a specific increase of HLA-DRhiCD11chi inflammatory monocytes that displayed a strong interferon (IFN)-stimulated gene signature in patients with mild COVID-19, which was absent in severe disease. Instead, we found evidence of emergency myelopoiesis, marked by the occurrence of immunosuppressive pre-neutrophils and immature neutrophils and populations of dysfunctional and suppressive mature neutrophils, as well as suppressive HLA-DRto monocytes in severe COVID-19. Our study provides detailed insights into systemic immune response to SARS-CoV-2 infection and it reveals profound alterations in the peripheral myeloid cell compartment associated with severe courses of COVID-19.

Implementation and evaluation of a novel real-time multiplex assay for SARS-CoV-2: In-field learnings from a clinical microbiology laboratory

The unprecedented scale of testing required to effectively control the coronavirus disease (COVID-19) pandemic has necessitated urgent implementation of rapid testing in clinical microbiology laboratories. To date, there are limited data available on the analytical performance of emerging commercially available assays for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and integration of these assays into laboratory workflows. Here, we performed a prospective validation study of a commercially available assay, the AusDiagnostics Coronavirus Typing (8-well) assay. Respiratory tract samples for SARS-CoV-2 testing were collected between 1st March and 25th March 2020. All positive samples and a random subset of negative samples were sent to a reference laboratory for confirmation. In total, 2,673 samples were analyzed using the Coronavirus Typing assay. The predominant sample type was a combined nasopharyngeal/throat swab (2,640/2,673; 98.8%). Fifty-four patients were positive for SARS-CoV-2 (0.02%) using the Coronavirus Typing assay; 53/54 (98.1%) positive results and 621/621 (100%) negative results were concordant with the reference laboratory. Compared to the reference standard, sensitivity of the Coronavirus Typing assay for SARS-CoV-2 was 100% [95% CI 93.2%-100%], specificity 99.8% [95% CI 99.1%-100%], positive predictive value 98.1% (95% CI 90.2%-99.7%] and negative predictive value 100% [95% CI 99.4%-100%]. In many countries, standard regulatory requirements for the introduction of new assays have been replaced by emergency authorizations and it is critical that laboratories share their post-market validation experiences, as the consequences of widespread introduction of a sub-optimal assay for SARS-CoV-2 are profound. Here, we share our in-field experience, and encourage other laboratories to follow suit.

An artificial intelligence system reveals liquiritin inhibits SARS-CoV-2 by mimicking type I interferon

The pandemic COVID-19 has spread to all over the world and greatly threatens safety and health of people. COVID-19 is highly infectious and with high mortality rate. As no effective antiviral treatment is currently available, new drugs are urgently needed. We employed transcriptional analysis to uncover potential antiviral drugs from natural products or FDA approved drugs. We found liquiritin significantly inhibit replication of SARS-CoV-2 in Vero E6 cells with EC50 = 2.39 M. Mechanistically, we found liquiritin exerts anti-viral function by mimicking type I interferon. Upregulated genes induced by liquiritin are enriched in GO categories including type I interferon signaling pathway, negative regulation of viral genome replication and etc. In toxicity experiment, no death was observed when treated at dose of 300 mg/kg for a week in ICR mice. All the organ indexes but liver and serum biochemical indexes were normal after treatment. Liquiritin is abundant in licorice tablet (~0.2% by mass), a traditional Chinese medicine. Together, we recommend liquiritin as a competitive candidate for treating COVID-19. We also expect liquiritin to have a broad and potent antiviral function to other viral pathogens, like HBV, HIV and etc.

Balloon occlusion technique combined with total arch replacement and frozen elephant trunk in the treatment of complex aortic arch diseases: an early clinical analysis of 100 cases in a single center / 中华胸心血管外科杂志

Objective:To evaluate the safety and efficacy of balloon occlusion technique combined with total arch replacement and frozen elephant trunk in the treatment of complex aortic arch diseases.Methods:The clinical data of 100 patients undergoing balloon occlusion technique combined with total arch replacement and frozen elephant trunk surgery in Fuwai Hospital from August 2017 to September 2018 were retrospectively reviewed, and the early clinical results were analyzed.Results:The average circulatory arrest time was(5.2±3.1) min. The lowest nasopharyngeal and bladder temperature was(27.9±1.0) ℃ and(29.2±1.2) ℃, respectively. One patient died in hospital due to multiple organ failure caused by acute liver failure, and a total of 4 patients died within 30 days. Other postoperative complications included cerebral infarction in 3 cases, paraplegia in 2 cases, low cardiac output syndrome requiring IABP assistance in 1 case, renal failure requiring continuous dialysis in 5 cases, redo for bleeding in 4 cases, reintubation in 3 cases, recurrent laryngeal nerve injury in 1 case, and osteofascial compartment syndrome in 1 case.Conclusion:Balloon occlusion technique combined with total arch replacement and frozen elephant trunk is safe and feasible in the treatment of complex aortic arch diseases. Its organ protection effect still needs to be confirmed by large sample comparison study.

Enhanced production of bacitracin via energy metabolism engineering in Bacillus licheniformis DW2 / 生物工程学报

Bacitracin is a broad-spectrum cyclic peptide antibiotic, and mainly produced by Bacillus. Energy metabolism plays as a critical role in high-level production of target metabolites. In this study, Bacillus licheniformis DW2, an industrial strain for bacitracin production, was served as the original strain. First, our results confirmed that elimination of cytochrome bd oxidase branch via deleting gene cydB benefited bacitracin synthesis. Bacitracin titer and ATP content were increased by 10.97% and 22.96%, compared with those of original strain, respectively. Then, strengthening cytochrome aa3 oxidase branch via overexpressing gene qoxA was conducive to bacitracin production. Bacitracin titer and ATP content were increased by 18.97% and 34.00%, respectively. In addition, strengthening ADP synthesis supply is also proven as an effective strategy to promote intracellular ATP accumulation, overexpression of adenosine kinase DcK and adenylate kinase AdK could all improve bacitracin titers, among which, dck overexpression strain showed the better performance, and bacitracin titer was increased by 16.78%. Based on the above individual methods, a method of combining the deletion of gene cydB and overexpression of genes qoxA, dck were used to enhance ATP content of cells to 39.54 nmol/L, increased by 49.32% compared to original strain, and bacitracin titer produced by the final strain DW2-CQD (DW2ΔcydB::qoxA::dck) was 954.25 U/mL, increased by 21.66%. The bacitracin titer produced per cell was 2.11 U/CFU, increased by 11.05%. Collectively, this study demonstrates that improving ATP content was an efficient strategy to improve bacitracin production, and a promising strain B. licheniformis DW2-CQD was attained for industrial production of bacitracin.

Enhanced dissolution and oral bioavailability of baicalein by cocrystallization / 中国药科大学学报

@#Baicalein(BE), a natural flavonoid mainly extracted from Radix Scutellaria, has comprehensive pharmacological actions such as anti-inflammation, anti-virus and anti-cancer activities. It belongs to BCS class II compound with relatively low oral bioavailability. The current study aims to improve its aqueous solubility and dissolution and hence to enhance its oral absorption by cocrystallization technique. Slurry crystallization method was employed to prepare baicalein cocrystal with co-former caffeine(CA), followed by physicochemical characterizations with DSC, XRPD and FTIR. Compared to BE and physical mixture of BE and CA, BE-CA cocrystal had a significantly higher dissolution of BE. In addition, in comparison to BE, this cocrystal achieved reduced time to peak(tmax)as well as significantly higher peak plasma concentrations(cmax)and area under the curve(AUCs)for both BE and its active metabolite baicalin(BI)in rats, suggesting enhanced the oral bioavailability of BE.

Effect analysis of combined treatment with multiple drugs on upper gastrointestinal bleeding in emergency internal medicine / 中国生化药物杂志

Objective To investigate the clinical effect of combined treatment of upper gastrointestinal bleeding in emergency internal medicine. Methods A total of 102 patients with upper gastrointestinal bleeding were enrolled in the Department of Emergency Gastroenterology, Peking Binhai University Hospital from June 2014 to October 2016. The patients were randomly divided into observation group and control group, 51 cases in each group.The control group were only given omeprazole sodium, tranexamic acid injection,the observation group were given Agkistrodon hemocoagulase for injection on patients on the basis of the control group.After treatment, the clinical curative effect of two groups of patients were evaluated, the hospitalization days, the average hemostasis time, blood transfusion, bowel recovery time, abdominal pain relief time, the adverse reactions occurred of the two groups were observed.Results The total effective rate of the observation group was significantly higher than that of the control group (P< 0.05). The hemostasis time,the time of hospitalization and the average blood transfusion in the observation group were significantly lower than those in the control group (P<0.05). The recovery time of bowel and the time of pain relief in the observation group were significantly lower than in the control group (P<0.05). There was no significant difference in the incidence of adverse reactions between the observation group and the control group.Conclusion Comprehensive treatment of upper gastrointestinal bleeding with emergency internal medicine can significantly improve the clinical efficacy, shorten the time of hemostasis and recovery, and is worthy of clinical application.

[Development of transcriptional regulators of Streptococcus mutans in cariogenic virulence].

Some transcriptional regulators contribute to the expression of Streptococcus mutans (S. mutans) cariogenic virulence factors. Although the target sequence transcriptional regulators anchored on the cell wall and the molecular mechanism of the regulation of S. mutans are yet to be clarified, certain global regulators potentially associated with the cariogenicity of S. mutans have been identified. This review is about these related transcriptional regulators, their function, and possible mechanisms.

Development of transcriptional regulators of Streptococcus mutans in cariogenic virulence / 华西口腔医学杂志

Some transcriptional regulators contribute to the expression of Streptococcus mutans (S. mutans) cariogenic virulence factors. Although the target sequence transcriptional regulators anchored on the cell wall and the molecular mechanism of the regulation of S. mutans are yet to be clarified, certain global regulators potentially associated with the cariogenicity of S. mutans have been identified. This review is about these related transcriptional regulators, their function, and possible mechanisms.

Supercapacitor electrode with a homogeneously Co3O4-coated multiwalled carbon nanotube for a high capacitance.

Cobalt oxide (Co3O4) was homogeneously coated on multiwalled carbon nanotube through a simple chemical deposition method and employed in supercapacitor electrodes. SEM image indicated the uniform distribution of Co3O4 nanoparticles on the surface of the multiwalled carbon nanotube. A maximum specific capacitance of 273 Fg(-1) was obtained at the charge-discharge current density of 0.5 Ag(-1). After 500 cycles of continuous charge-discharge process, about 88% of the initial capacity could be retained.

Research progress on gene involved in tooth agenesis / 华西口腔医学杂志

Tooth agenesis, belonging to the abnormal tooth development, is a common disease in clinic. The disease not only affects the person's chewing function, but also influences the pronunciation, appearance and mental health. In the past, genetic linkage and molecular biology research have made clear of part of the genetic mutations' sites of the syndromic and non-syndromic tooth agenesis. Although the mechanism was not clear yet, but the important mutations are now known to be involved in many factors. Thesyndromic and non-syndromic tooth agenesis related gene are reviewed in this paper.