AQP4-DARPin1: A Chimeric Antigen Based on Scaffold Protein DARPin for Efficient Detection of AQP4-IgG in NMOSD

AQP4-IgG is an autoantibody associated with neuromyelitis optica spectroscopic disorder (NMOSD), a central nervous system inflammatory disease that requires early diagnosis and treatment. We designed two fusion proteins, AQP4-DARPin1 and AQP4-DARPin2, comprising the complete antigenic epitopes of aquaporin-4 (AQP4) and the constant region of the scaffold protein DARPin. These fusion proteins were expressed and purified from Escherichia coli and coated on microplates to develop an efficient method for detecting AQP4-IgG. Molecular dynamics simulation revealed that the fusion of AQP4 extracellular epitopes with DARPin did not alter the main structure of DARPin. The purified AQP4-DARPins bound recombinant antibody rAb-53 (AQP4-IgG) with affinities of 135 and 285 nM, respectively. Enzyme-linked immunosorbent assay (ELISA) and immunoprecipitation demonstrated that AQP4-DARPin1 specifically recognized AQP4-IgG in the NMOSD patient serum. AQP4-DARPin1 as a coated antigen showed higher ELISA signal and end point dilution ratio than full-length AQP4. Our AQP4-DARPin1-coated AQP4-IgG ELISA had 100% specificity and 90% sensitivity. These results indicate that AQP4-DARPin1, compared to existing detection strategies that use full-length or extracellular loop peptides of AQP4, provides a new and more effective approach to the ELISA detection of NMOSD.

Biparatopic Nanobody-Based Immunosorbent for the Highly Selective Elimination of Tumor Necrosis Factor-α

Removing the overexpressed TNF-α by hemoperfusion positively affects clinical treatments for diseases such as autoimmune disease and sepsis. However, clearance ratios of adsorbents targeting TNF-α were limited by the extremely low concentration of TNF-α (mostly <1000 ng/L in sepsis) and hydrophobic interactions. In this work, biparatopic nanobodies (NbC21) with a high affinity of 19.9 pM, which bind to two distinct sites of TNF-α, were constructed as high-affinity ligands for the immunosorbent. The theoretical maximum adsorption capacity estimated from the Langmuir isotherm was up to 18.22 mg/g gel. The prepared immunosorbent (NbC21-sorbent) had an outstanding TNF-α clearance ratio of approximately 96% during the dynamic adsorption test, with a sorbent-to-serum ratio of 1:1000. Additionally, it demonstrated favorable hemocompatibility and a prolonged storage capability. The results indicated that the biparatopic nanobody immunosorbent exhibited significant potential for clinical applications as it met the stringent criteria for both efficacy and safety.

Chimeric AQP4-based immunosorbent for highly-specific removal of AQP4-IgG from blood

Anti-aquaporin-4 autoantibodies (AQP4-IgG) are implicated in the pathogenesis of neuromyelitis optica spectrum disorders (NMOSD), and their removal from the blood circulation is considered to be an effective method for acute treatment. An ideal extracorporeal AQP4-IgG removal system should have high specificity, which means that it can selectively remove AQP4-IgG without affecting normal immunoglobulins. However, the conventional tryptophan immobilized column lacks sufficient specificity and cannot achieve this goal. In this study, we successfully prepared a fusion protein chimeric AQP4, which consists of the complete antigenic epitopes of human AQP4 and the constant region of scaffold protein DARPin. Chimeric AQP4 was expressed and purified from Escherichia coli, and then immobilized on agarose gel as a ligand for selective capture of AQP4-IgG immunosorbent. The prepared immunosorbent had a theoretical maximum adsorption capacity of 20.48 mg/g gel estimated by Langmuir isotherm. In vitro plasma perfusion tests demonstrated that the chimeric AQP4 coupled adsorbent had remarkable adsorption performance, and could eliminate more than 85 % of AQP4-IgG under the gel-to-plasma ratio of 1:50. Moreover, it exhibited high specificity because other human plasma proteins were not adsorbed in the dynamic adsorption experiment. These results suggest that the chimeric AQP4 coupled immunosorbent can provide a new approach for specific immunoadsorption (IA) treatment of NMOSD.

Nanobody-functionalized conduit with built-in static mixer for specific elimination of cytokines in hemoperfusion

Removing excessively produced cytokines is of paramount significance in blood purification therapy for hypercytokinemia-associated diseases. In this study, we devised a conduit that is modified with nanobodies (Nb) and incorporates static mixers (Nb-SMC) to eliminate surplus cytokines from the bloodstream. The low-pressure-drop (LPD) static mixer, with each unit featuring two 90°-crossed blades, was strategically arranged in a tessellated pattern on the inner wall of the conduit to induce turbulent mixing effects during the flow of blood. This arrangement enhances mass transfer and molecular diffusion, thereby assisting in the identification and elimination of cytokines. By utilizing computational fluid dynamics (CFD) studies, the Nb-SMC was rationally designed and prepared, ensuring an optimal interval between two mixer units (H/G = 2.5). The resulting Nb-SMC exhibited a remarkable selective clearance of IL-17A, reaching up to 85 %. Additionally, the process of Nb immobilization could be adjusted to achieve the simultaneous removal of multiple cytokines from the bloodstream. Notably, our Nb-SMC displayed good blood compatibility without potential adverse effects on the composition of human blood. As the sole documented static mixer-integrated conduit capable of selectively eliminating cytokines at their physiological concentrations, it holds promise in the clinical potential for hypercytokinemia in high-risk patients. STATEMENT OF SIGNIFICANCE: High-efficient cytokines removal in critical care still remains a challenge. The conduit technique we proposed here is a brand-new strategy for cytokines removal in blood purification therapy. On the one hand, nanobody endows the conduit with specific recognition of cytokine, on the other hand, the build-in static mixer enhances the diffusion of antigenic cytokine to the ligand. The combination of these two has jointly achieved the efficient and specific removal of cytokine. This innovative material is the only reported artificial biomaterial capable of selectively eliminating multiple cytokines under conditions close to clinical practice. It has the potential to improve outcomes for patients with hypercytokinemia and reduce the risk of adverse events associated with current treatment modalities.

Norovirus outbreaks in hospitals in China: a systematic review

BACKGROUND

Norovirus outbreaks in hospitals can potentially impair patient care and result in significant financial expenses. There is currently limited information on hospital norovirus outbreaks in the Chinese mainland.

AIM

To systematically review the published literature to describe the characteristics of norovirus outbreaks in Chinese mainland hospitals to facilitate prompt identification and control of outbreaks.

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis standards. Databases including PubMed, Web of Science, and Chinese Journals Online databases (China National Knowledge Infrastructure (CNKI), Chinese Wan Fang digital database (WANFANG) were searched from inception to July 18th, 2022.

FINDINGS

A total of 41 norovirus Chinese hospital outbreaks occurring before July 18th, 2022 were reported in 32 articles. Most reported outbreaks were from Shanghai and Beijing, and occurred in December and January. Cases were mainly adults. The male:female ratio was 1.22:1. The majority of cases in norovirus outbreaks were hospitalized patients (56.82%); medical staff were affected in 15 outbreaks. Norovirus outbreaks occurred in both private and public hospitals, and in secondary and tertiary care centres, and occurred mainly in internal medicine and geriatric departments. Person-to-person transmission was the primary transmission mode and GII was more prevalent.

CONCLUSION

Norovirus outbreaks in hospitals can affect both patients and healthcare workers, sometimes causing serious financial losses. In order to have a more complete understanding of the disease burden caused by norovirus outbreaks, surveillance needs to be established in hospitals.

An oral polyphenol host-guest nanoparticle for targeted therapy of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a global public health challenge that affects millions of people. Current medical treatments for IBD are not fully effective and may cause undesirable side effects on patients. Thus, there is an urgent need for safe, simple, and efficacious strategies to treat IBD in clinical settings. Here, we develop an oral polyphenol nanoparticle (PDT) by assembling dexamethasone sodium phosphate (DSP)-loaded poly-β-cyclodextrin with tannic acid via host-guest interactions for treating IBD. This one-step assembly process is rapid (within 10 s), reproducible, and free of harmful chemical agents, which can facilitate its clinical translation. PDT is negatively charged due to the three components, which enable it to specifically target the positively charged inflamed colonic mucosa through electrostatic attraction, thus localizing the drug at the inflamed site to reduce systemic exposure and side effects. Furthermore, PDT exhibits a strong reactive oxygen species (ROS)-scavenging ability derived from the tannic acid component, which can alleviate ROS-mediated inflammatory responses and ameliorate IBD symptoms. Compared with free DSP, PDT demonstrates sustained DSP release behavior in vitro and in vivo, as well as enhanced therapeutic efficacy in a colitis mouse model. These results suggest that PDT might be a potential therapeutic agent for the treatment of IBD. Moreover, this facile polyphenol host-guest assembly strategy may provide a promising drug-delivery platform for treating various diseases STATEMENT OF SIGNIFICANCE: To develop safe and effective treatments for inflammatory bowel disease (IBD), we have designed an oral polyphenol nanoparticle (PDT) using the host-guest assembly of dexamethasone sodium phosphate (DSP)-loaded poly-β-cyclodextrin with tannic acid. Through in vitro and in vivo experiments, PDT has demonstrated remarkable inflammation-targeting, ROS-scavenging, and anti-inflammatory properties, along with sustained release of DSP. Moreover, in an IBD mouse model, PDT has shown significantly improved therapeutic efficacy compared to free DSP. The host-guest assembly strategy employed for PDT is noteworthy for its rapidity, reproducibility, and safety due to the absence of harmful chemicals, holding great promise for designing a diverse range of nanomedicines customized for treating various diseases.

Effect of anterior communicating artery patency on the flow velocity in bilateral carotid artery stenosis after carotid endarterectomy

BACKGROUND

The effect of anterior communicating artery (ACoA) patency on the flow velocity of the extracranial carotid arteries is unclear.

METHODS

A total of 285 patients with carotid artery stenosis were included between January 2019 and January 2021. All patients received unilateral carotid endarterectomy (CEA). The patients were classified into ACoA-patent (161) and ACoA-nonpatent (124) groups using digital subtraction angiography (DSA) and/or computed tomography angiography (CTA). The peak systolic velocity (PSV) and end-diastolic velocity (EDV) measured by carotid duplex ultrasonography (CDU) were compared between both groups, pre- and post-CEA.

RESULTS

There was no significant difference in the risk factors for cerebrovascular disease between the two groups. Within 1 week after CEA, the PSV and EDV on operative and nonoperative carotid (contralateral carotid in the same patient) arteries decreased significantly (both p < 0.01). Comparison of nonoperative carotid artery pre- and post-CEA between the two groups showed that post-CEA PSV and EDV in the ACoA-patent group were significantly lower than that of pre-CEA (PSV and EDV, t = 11.507 and 6.716, respectively, both p < 0.001) (according to the Society of Radiologists in Ultrasound Consensus Conference [SRUCC] PSV standard). There was no significant difference in the ACoA-nonpatent group (PSV: t = 1.924, p = 0.057; EDV: t = 1.237, p = 0.218). In the nonoperative carotid artery of the ACoA-patent group, the degree of stenosis assessed by CDU was inconsistent with that of DSA/CTA (κ = 0.294), whereas that in the ACoA-nonpatent group had a high consistency (κ = 0.982). Among 161 ACoA-patent cases, 68 showed overestimated stenosis.

CONCLUSIONS

The patent ACoA increases PSV and EDV, causing an overestimation of carotid artery stenosis.

Effects of plaque characteristics and artery hemodynamics on the residual stenosis after carotid artery stenting

OBJECTIVE

Carotid artery stenting (CAS) has become an alternative strategy to carotid endarterectomy for carotid artery stenosis. Residual stenosis was an independent risk factor for restenosis, with the latter affecting the long-term outcomes of CAS. This multicenter study aimed to evaluate the echogenicity of plaques and hemodynamic alteration by color duplex ultrasound (CDU) examination and investigate their effects on the residual stenosis after CAS.

METHODS

From June 2018 to June 2020, 454 patients (386 males and 68 females) with a mean age of 67.2 ± 7.9 years, who underwent CAS from 11 advanced stroke centers in China were enrolled. One week before recanalization, CDU was used to evaluate the responsible plaques, including the morphology (regular or irregular), echogenicity of the plaques (iso-, hypo-, or hyperechoic) and calcification characteristics (without calcification, superficial calcification, inner calcification, and basal calcification). One week after CAS, the alteration of diameter and hemodynamic parameters were evaluated by CDU, and the occurrence and degree of residual stenosis were determined. In addition, magnetic resonance imaging was performed before and during the 30-day postprocedural period to identify new ischemic cerebral lesions.

RESULTS

The rate of composite complications, including cerebral hemorrhage, symptomatic new ischemic cerebral lesions, and death after CAS, was 1.54% (7/454 cases). The rate of residual stenosis after CAS was 16.3% (74/454 cases). After CAS, both the diameter and peak systolic velocity (PSV) improved in the preprocedural 50% to 69% and 70% to 99% stenosis groups (P < .05). Compared with the groups without residual stenosis and with <50% residual stenosis, the PSV of all three segments of stent in the 50% to 69% residual stenosis group were the highest, and the difference in the midsegment of stent PSV was the largest (P < .05). Logistic regression analysis showed that preprocedural severe (70% to 99%) stenosis (odds ratio [OR], 9.421; P = .032), hyperechoic plaques (OR, 3.060; P = .006) and plaques with basal calcification (OR, 1.885; P = .049) were independent risk factors for residual stenosis after CAS.

CONCLUSIONS

Patients with hyperechoic and calcified plaques of the carotid stenosis are at a high risk of residual stenosis after CAS. CDU is an optimal, simple and noninvasive imaging method to evaluate plaque echogenicity and hemodynamic alterations during the perioperative period of CAS, which can help surgeons to select the optimal strategies and prevent the occurrence of residual stenosis.

[C2 pedicle screw insertion assisted by mobilization of the vertebral artery in cases with high-riding vertebral artery]

Objective: To examine the feasibility, safety, and efficacy of mobilization of the vertebral artery for C2 pedicle screws in cases with high-riding vertebral artery (HRVA). Methods: The clinical data of 12 patients with basilar invagination and atlantoaxial dislocation underwent atlantoaxial reduction and fixation in the Department of Neurosurgery, the First Affiliated Hospital of University of Science and Technology of China between January 2020 and November 2021 were retrospectively analyzed. All patients had high-riding vertebral artery on at least one side that prohibited the insertion of C2 pedicle screws. There were 2 males and 10 females aged (48.0±12.8) years (range: 17 to 67 years). After correction of vertical dislocation during the operation, the C2 pedicle screw insertion and occipitocervical fixation and fusion were performed using the vertebral artery mobilization technique. Neurological function was assessed using the Japanese Orthopedic Association (JOA) scale. The preoperative and postoperative JOA score and the main radiological measurements, including the anterior atlantodental interval (ADI), the distance of the odontoid tip above the Chamberlain line, the clivus-canal angle, were collected and compared by paired t-test. Results: Mobilization of the high-riding vertebral artery was successfully completed, and C2 pedicle screws were then fulfilled after the vertebral artery was protected. There was no injury to the vertebral artery during the operation. Meanwhile, no severe surgical complications such as cerebral infarction or aggravated neurological dysfunction occurred during the perioperative period. Satisfactory C2 pedicle screw placement and reduction were achieved in all 12 patients. All patients achieved bone fusion 6 months after surgery. No looseness and shift in internal fixation or reduction loss was observed during the follow-up period. Compared to the preoperative, the postoperative ADI decreased from (6.1±1.9) mm to (2.0±1.2) mm (t=6.73, P<0.01), the distance of the odontoid tip above the Chamberlain line decreased from (10.4±2.5) mm to (5.5±2.3) mm (t=7.12, P<0.01), the clivus-canal angle increased from (123.4±11.1) ° to (134.7±9.6) ° (t=2.50, P=0.032), the JOA score increased from 13.3±2.1 to 15.6±1.2 (t=6.99, P<0.01). Conclusion: The C2 pedicle screw insertion assisted by mobilization of the vertebral artery is safe and considerably effective, providing a choice for internal fixation in cases with high-riding vertebral arteries.

One-Step Assembly of Versatile Multifunctional Coatings Based on Host-Guest and Polyphenol Chemistry

Developing a facile, efficient, and versatile polyphenol coating strategy and exploring its novel applications are of great significance in the fields of material surfaces and interfaces. Herein, a one-step assembly strategy for constructing novel tannic acid (TA) coatings via a solvent evaporation method is reported using TA and polycyclodextrin (PCD) particles (TPP). TPP with a high phenolic group activity of 88% integrates the advantages of host-guest and polyphenol chemistry. The former can drive TPP dynamically assemble into a large and collective aggregation activated by high temperature or density, and the latter provides excellent adhesion properties to substrates (0.9 mg cm^-2 ). TPP can assemble into a coating (TPC) rapidly on various substrates within 1 h at 37 °C while with a high availability of feed TPP (≈90%). The resulting TPC is not only high-temperature steam-sensitive for use as an anti-fake mask but also pH-sensitive for transforming into a free-standing film under physiological conditions. Moreover, various metal ions and functional particles can incorporate into TPC to extend its versatile properties including antibacterial activity, enhanced stability, and conductivity. This work expands the polyphenol coating strategy and builds up a one-step and efficient preparation platform of polyphenol coating for multiapplication prospects in various fields.

[Clinicopathological characteristics of gastric SMARCA4-deficient undifferentiated/rhabdoid carcinoma]

Objective: To investigate the clinicopathological features and immunohistochemical phenotypes of gastric SMARCA4-deficient undifferentiated carcinoma, and to discuss the daily diagnostics of this entity and analyze its prognosis. Methods: The cases of gastric SMARCA4-deficient undifferentiated carcinoma diagnosed at the Department of Pathology, Peking University Cancer Hospital, China from January 2010 to August 2022 were collected. The histological sections were reviewed, the immunohistochemical results and clinicopathological features were analyzed, and relevant literature was reviewed. Results: Pure foci of undifferentiated carcinoma were seen in 7 cases, and 1 case was accompanied by a moderately differentiated tubular adenocarcinoma component. Undifferentiated carcinoma foci showed similar sheet-like or solid diffuse growth pattern, medium-sized tumor cells characterized by 1-2 nucleoli, and abundant cytoplasm and rhabdoid appearance. The average patient age was 65±8 years. Six patients were male and 2 were female. Immunohistochemical staining showed that undifferentiated carcinoma of all 8 tumors were negative for SMARCA4 (BRG1). Among 7 patients who underwent SMARCA2 (BRM) and SMARCB1 (INI1) staining, 4 cases showed loss of BRM expression, 2 cases showed weakly positive staining, and 1 case was diffusely positive, but all 7 cases were diffusely strong positive for INI1. The neuroendocrine marker, synaptophysin, was weakly positive in 5 cases, while CgA and CD56 were negative in 8 cases. Ki-67 index was more than 70%. Two cases were mismatch repair deficient and showed the loss of MLH1/PMS2 expression, while 1 case showed only MSH2 loss. PD-L1 staining showed that combined positive score (CPS)≥1 in 4 cases (CPS ranging from 1 to 55) and CPS<1 in the other 3 cases. Four patients had clinical stage Ⅳ disease. Two of them died within 3 months after diagnosis. Conclusions: Gastric SMARCA4-deficient undifferentiated carcinoma/rhabdoid carcinoma is a rare group of highly malignant tumors with a poor prognosis. Loss of the core subunit of SWI/SNF complex may be associated with the development of dedifferentiated histological pattern and aggressive tumor progression, which may be more frequently accompanied with mismatch repair deficiency.

Bacteria-Induced Colloidal Encapsulation for Probiotic Oral Delivery

Probiotic oral delivery has crucial implications in biomedical engineering, but its oral bioavailability remains unsatisfactory because of the limited survival and colonization of probiotics in the harsh gastrointestinal tract. Here, a bacteria-induced encapsulation strategy is achieved by assembling metastable colloids to enhance the oral bioavailability of probiotics. The colloids (NTc) composed of amino-modified poly-β-cyclodextrin and tannic acid are formed based on the balance of host-guest interaction-driven attraction and electrostatic repulsion between colloids. Negatively charged probiotics electrostatically attract positively charged NTc to break the balance and induce further assembly surrounding the probiotics. Through a facile one-step mixing, 97% of bacteria are rapidly encapsulated into NTc shells within 10 s, with a high utilization rate of feeding colloids of 91%. More importantly, we show that the compact, thick, and positively charged NTc shells synergistically endow the encapsulated probiotics with strong resistance against simulated gastric fluid with an excellent survival rate of up to 19%, 7500 times superior to the commercial enteric material L100. Moreover, owing to the dynamically noncovalent and self-adaptive nature of host-guest interactions, NTc shells support the proliferation of the encapsulated EcN comparable with that of the naked EcN. In vitro and in vivo experiments also confirm that the NTc-encapsulated probiotics possess durable intestinal adhesion, continuous proliferation activity, enhanced oral bioavailability, good oral biosafety, and excellent therapeutic efficacy in a colitis mouse model. This facile bacteria-induced colloidal encapsulation strategy may extend to various microbes as oral bioagents for treating various diseases.

Structural and enzymatic characterization of Bacillus subtilis R,R-2,3-butanediol dehydrogenase

2,3-butanediol dehydrogenase (BDH, EC 1.1.1.76) also known as acetoin reductase (AR, EC 1.1.1.4) is the key enzyme converting acetoin (AC) into 2,3-butanediol (BD) and undertaking the irreversible conversion of diacetyl to acetoin in various microorganisms. The existence of three BDHs (R,R-, meso-, and S,S-BDH) product different BD isomers. Catalyzing mechanisms of meso- and S,S-BDH have been understood with the assistance of their X-ray crystal structures. However, the lack of structural data for R,R-BDH restricts the integral understanding of the catalytic mechanism of BDHs. In this study, we successfully crystallized and solved the X-ray crystal structure of Bacillus subtilis R,R-BDH. A zinc ion was found locating in the catalytic center and coordinated by Cys37, His70 and Glu152, helping to stabilize the chiral substrates observed in the predicted molecular docking model. The interaction patterns of different chiral substrates in the molecular docking model explained the react priority measured by the enzyme activity assay of R,R-BDH. Site-directed mutation experiments determined that the amino acids Cys37, Thr244, Ile268 and Lys340 are important in the catalytically active center. The structural information of R,R-BDH presented in this study accomplished the understanding of BDHs catalytic mechanism and more importantly provides useful guidance for the directional engineering of R,R-BDH to obtain high-purity monochiral BD and AC.

Numerical analyses of seed morphology and its taxonomic significance in the genus Oxytropis DC. (Fabaceae) from northwestern China

The lack of diagnostic taxonomic characteristics in some species complexes leave the species delimitation of Oxytropis DC. unresolved. Seed morphological features have proved to be useful diagnostic and taxonomic characteristics in Fabaceae. However, there are few systematic studies on the seed characteristics of Oxytropis. Here, we used scanning electron and stereoscopic microscopy to investigate the seed characteristics of 35 samples obtained from 21 Oxytropis species from northwest China. Our examination showed two main types of hilum positions, terminal and central, and five different types of seed shapes: prolonged semielliptic, reniform, prolonged reniform, quadratic, and cardiform. Seven different sculpturing patterns were identified: scaled, regulated, lophate with stellated testa cells, simple reticulate, rough, compound reticulate, and lophate with rounded testa cells. The seeds ranged from 1.27 to 2.57 mm in length and from 1.18 to 2.02 mm in width, and the length-to-width ratio ranged from 0.89 to 1.55 mm. The seed shape was constant within species and was useful for species delimitation within the genus Oxytropis when combined with other macroscopic traits. In contrast, the sculpturing patterns were highly variable at the species level and could not be used for species identification. Results of the cluster analysis and principal component analysis (PCA) indicated that the seed traits of Oxytropis species are useful for taxa identification at the species level, but have low taxonomic value at the section level.

Baits-trap chip for accurate and ultrasensitive capture of living circulating tumor cells

Accurate analysis of living circulating tumor cells (CTCs) plays a crucial role in cancer diagnosis and prognosis evaluation. However, it is still challenging to develop a facile method for accurate, sensitive, and broad-spectrum isolation of living CTCs. Herein, inspired by the filopodia-extending behavior and clustered surface-biomarker of living CTCs, we present a unique baits-trap chip to achieve accurate and ultrasensitive capture of living CTCs from peripheral blood. The baits-trap chip is designed with the integration of nanocage (NCage) structure and branched aptamers. The NCage structure could "trap" the extended filopodia of living CTCs and resist the adhesion of filopodia-inhibited apoptotic cells, thus realizing the accurate capture (∼95% accuracy) of living CTCs independent of complex instruments. Using an in-situ rolling circle amplification (RCA) method, branched aptamers were easily modified onto the NCage structure, and served as "baits" to enhance the multi-interactions between CTC biomarker and chips, leading to ultrasensitive (99%) and reversible cell capture performance. The baits-trap chip successfully detects living CTCs in broad-spectrum cancer patients and achieves high diagnostic sensitivity (100%) and specificity (86%) of early prostate cancer. Therefore, our baits-trap chip provides a facile, accurate, and ultrasensitive strategy for living CTC isolation in clinical. STATEMENT OF SIGNIFICANCE: A unique baits-trap chip integrated with precise nanocage structure and branched aptamers was developed for the accurate and ultrasensitive capture of living CTCs. Compared with the current CTC isolation methods that are unable to distinguish CTC viability, the nanocage structure could not only "trap" the extended-filopodia of living CTCs, but also resist the adhesion of filopodia-inhibited apoptotic cells, thus realizing the accurate capture of living CTCs. Additionally, benefiting from the "baits-trap" synergistic effects generated by aptamer modification and nanocage structure, our chip achieved ultrasensitive, reversible capture of living CTCs. Moreover, this work provided a facile strategy for living CTC isolation from the blood of patients with early-stage and advanced cancer, exhibiting high consistency with the pathological diagnosis.

[Analysis on infection sources and transmission chains of three outbreaks caused by 2019-nCoV Omicron variant in Beijing, China]

Objective: To investigate the infection sources and the transmission chains of three outbreaks caused by 2019-nCoV Omicron variant possibly spread through cross-border logistics in Beijing. Methods: Epidemiological investigation and big data were used to identify the exposure points of the cases. Close contacts were traced from the exposure points, and the cases' and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: The Omicron variant causing 3 outbreaks in Beijing from January to April, 2022 belonged to BA.1, BA.1.1 and BA.2. The outbreaks lasted for 8, 12 and 8 days respectively, and 6, 42 and 32 cases infected with 2019-nCoV were reported respectively. International mail might be the infection source for 1 outbreak, and imported clothes might be the infection sources for another 2 outbreaks. The interval between the shipment start time of the imported goods and the infection time of the index case was 3-4 days. The mean incubation period (Q₁, Q₃) was 3 (2,4) days and the mean serial interval (Q₁, Q₃) was 3 (2,4)days. Conclusions: The 3 outbreaks highlighted the risk of infection by Omicron variant from international logistics-related imported goods at normal temperature. Omicron variant has stronger transmissibility, indicating that rapid epidemiological investigation and strict management are needed.

Facile surface treatment strategy to generate dense lysozyme layer on ultra-high molecular weight polyethylene enabling inhibition of bacterial biofilm formation

Medical plastics such as those found in endotracheal tubes are widely used in intensive care units for the treatment of critically ill patients. Although commonplace in hospital environment, these catheters are at a high risk of bacterial contamination and have been found responsible for numerous health-care-associated infections. Antimicrobial coatings that can prevent harmful bacterial growth are required to reduce the occurrence of such infections. In this study, we introduce a facile surface treatment strategy that could form antimicrobial coatings on the surface of average medical plastics. The strategy involves treatment of activated surfaces with lysozyme, a natural antimicrobial enzyme presenting in human lacrimal gland secretions which is widely used for wound healing. Using ultra-high molecular weight polyethylene (UHMWPE) as the representative surface, oxygen/argon plasma treatment for 3 min led to the increase of surface roughness and the generation of negatively charged groups, with the zeta potential measured as -94.5 mV at pH 7. The activated surface could accommodate lysozyme with a density of up to 0.3 nmol/cm² through electrostatic interaction. Antimicrobial activity of the resulting surface (UHMWPE@Lyz) was characterized with Escherichia coli and Pseudomonas sp. strains, and the treated surface significantly inhibited the bacterial colonization and the formation of biofilm compared to the untreated UHMWPE. This method of constructing an effective lysozyme-based antimicrobial coating is a generally applicable, simple and fast process for surface treatment with no adverse solvent and wastes involved.

Reduction-Activatable Fluorogenic Nanobody for Targeted and Low-Background Bioimaging

Environment-sensitive fluorogenic antibodies enable target-specific bioimaging with reduced unspecific background signal and improved spatiotemporal resolution. However, current strategies for the construction of fluorogenic antibodies are hard to handle due to challenges that lie in the prior design of fluorogenic probes and subsequent antibody labeling. Here, we report a simple strategy to generate a fluorogenic nanobody, which we term D-body, by in situ incorporation of a reduction-responsive Nile blue foldamer which is self-quenched via a dimerization-caused quenching mechanism. The D-body can be efficiently internalized by cells with high epidermal growth factor receptor expression levels and is highly fluorogenic upon lysosomal activation, allowing wash-free cell imaging with exquisite specificity and fast in vivo imaging with a high tumor-to-background ratio. The modular D-body is readily available and easy to handle, offering a platform that is highly tunable for bioimaging applications.

[Development of first-class biotechnology major under new economic situation]

The rapid development of bioeconomy urgently needs the support of biotechnology talents. Establishing an innovative training mode of biotechnology talents can provide support for regional economic development and industrial upgrading. Closely revolved around the concepts of new engineering disciplines development, such as serving the national strategy, docking industry, leading the future development and student-centered, a new economy-oriented training system was developed in School of Bioengineering of Dalian University of Technology. These systems include interdisciplinary curriculum system reconstruction, project-based teaching mode reform, evaluation system implementation and other aspects. The reform and exploration of the first-class biotechnology major under the new economic situation, puts forward the theory of value guidance, deep foundation, strong sense of innovation, technical and non-technical core ability literacy. This reform meets the industry demand for talent diversification, personalization, and dynamic change, helps the merge of industry and education, which provides a way for fostering first-class biotechnology-majored undergraduates.

[Investigation for pathological interpretation criteria and its prognostic value for P53 expression in Chinese diffuse large B-cell lymphoma]

Objective: To explore the feasibility of predicting TP53 mutation risk by immunohistochemical staining (IHC) pattern of P53 in Chinese diffuse large B-cell lymphoma (DLBCL) and its correlation with a prognostic difference. Methods: Between January 2021 and December 2021, 51 DLBCL cases at Beijing Boren Hospital were gathered. These cases had both IHC and next-generation sequencing (NGS) results. IHC classified the P53 protein expression pattern into a loss (<1% ) , diffuse (>80% ) , and heterogeneous (1% -80% ) . The sensitivity and specificity of the predicting TP53 mutation by IHC were assessed by comparing the results of the NGS, and the TP53 high mutation risk group included both loss and diffuse expression of P53. From June 2016 to September 2019, Peking University Cancer Hospital collected 131 DLBCL cases with thorough clinicopathological and follow-up data. From their tumor blocks, tissue microarray blocks were made for IHC evaluation of P53 expression pattern, and prognosis effect of P53 studies. Results: Among 51 cases with both IHC and NGS results, 23 cases were classified as TP53 high mutation risk (7 cases loss and 16 cases diffuse) , 22/23 cases were proved with mutated TP53 by NGS. Only 1 of the 28 cases classified as TP53 low mutation risk was proved with mutated TP53 by NGS. IHC had a sensitivity and specificity of 95.7% and 96.4% for predicting TP53 mutation. NGS identified a total of 26 TP53 mutations with a mutation frequency of 61.57% (13.41% -86.25% ) . In the diffuse group, 16 missense mutations and 2 splice mutations were detected; 6 truncating mutations and 1 splice mutation were detected in the loss group; 1 truncating mutation was detected in the heterogeneous group. Multivariate analysis demonstrated that TP53 cases with high mutation risk have impartial adverse significance for the 131 patients included in survival analysis (HR=2.612, 95% CI 1.145-5.956, P=0.022) . Conclusion: IHC of P53 exhibiting loss (<1% ) or diffuse (>80% ) pattern indicated TP53 high mutation risk, IHC can predict TP53 mutation with high specificity and sensitivity. TP53 high mutation risk is an independent predictor for adverse survival.

Correlation analysis between risk factors, BMD and serum osteocalcin, CatheK, PINP, β-crosslaps, TRAP, lipid metabolism and BMI in 128 patients with postmenopausal osteoporotic fractures

OBJECTIVE

Our aim is to investigate the correlation between risk factors of postmenopausal osteoporotic fracture, BMD and Bone turnover markers, lipid metabolism and BMI.

SUBJECTS AND METHODS

The Cox proportional hazard model was used to conduct univariate and multivariate analysis to screen the risk factors related to postmenopausal osteoporotic fractures. Blood samples were collected to detect biochemical markers of bone turnover, blood lipids content, and then measure the BMI of the survey subjects. BMD was measured and its correlation with biochemical markers of bone turnover, lipid metabolism and BMI was analyzed.

RESULTS

Cox univariate analysis indicated that average age, menopause, years since menopause, number of deliveries, and limb spasm are associated covariates of postmenopausal osteoporotic fractures. Where, BMD severity, history of hysterectomy or ovariectomy, and years since menopause are significant covariates for the incidence of postmenopausal osteoporotic fractures. The correlation study with lipid metabolism found that the smaller the BMI value, the greater the BMD loss; the smaller the TG value, the greater the BMD loss, exhibiting a downward trend. No difference was observed between HDL-C and LDL-C content, and the difference was not statistically significant (p>0.05). Femoral neck BMD was negatively correlated with CatheK, serum osteocalcin, PINP, β-crosslaps and TRAP, and lumbar spine BMD was also negatively correlated with CatheK, serum osteocalcin, PINP, β-crosslaps and TRAP.

CONCLUSIONS

Biochemical markers of bone turnover are highly expressed in postmenopausal women and increase with the decrease of bone density, which can be used as markers for disease prediction. Combined with BMI, triglyceride and other related indicators, and closely related factors such as the patient's age, the number of deliveries, it is possible to predict the incidence of PMOP fractures early.

[Survey on infection source of a cold-chain product associated COVID-19 epidemic caused by 2019-nCoV Delta variant in Beijing]

Objective: To investigate the source and the transmission chain of a cold-chain product associated COVID-19 epidemic caused by 2019-nCoV Delta variant in Beijing. Methods: Epidemiological investigation were used to verify the exposure points of the cases. Close contacts were traced from the exposure points, and human and environmental samples were collected for nucleic acid tests. Positive samples were analyzed by gene sequencing. Results: A total of 112 cases of COVID-19 were reported in the epidemic from January 18 to February 6, 2022 in Beijing. Except for 1 case was uncertain, there were epidemiological links among 111 cases. The source of infection was the packages of imported cold-chain products from Southeast Asia, which were harvested and stored in a local cold-storage in January 2021, and packaged and sent to the cold-storage A in A district in June 2021, and then sold in batches in cold-storage B in B district from January 2022. The first case was infected in the handling of positive frozen products, and then 77 cases occurred due to working, eating and living together with the index case in the cold-storage B, cold-storage C and restaurant D. Besides the cold-storage B, C and the restaurant D, there were 16 sub-transmission chains, resulting in additional 35 cases. Conclusion: The epidemic indicated that the risk of 2019-nCoV infection from imported cold-chain products contaminated by package and highlighted the importance to strengthen the management of cold-chain industry in future.

SnoopLigase Enables Highly Efficient Generation of C-C-Linked Bispecific Nanobodies Targeting TNF-α and IL-17A

Bispecific antibodies (bis-Nbs) have been extensively developed since the concept was devised over the decades. Taking advantage of the superior characteristics of nanobodies, bis-Nbs exhibit an emerging tendency to become the new generation of research and diagnostic tools. Traditional strategies to connect the homo- or heterogeneous monomers are commonly applied, but there are still technical issues to generate the bispecific molecules as efficiently as designed. Here, we utilize SnoopLigase to directly tether the C terminus (C-C) of the tagged nanobodies against tumor necrosis factor-α (TNF-α) and interleukin-17A (IL-17A). Under optimal conditions, the yield of C-C-linked bis-Nbs can reach as high as 70% due to the existence of SnoopLigase. The prepared bis-Nbs possessed similar or even higher affinity as the monomers and significantly inhibited the proliferation and migration of rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS) induced by TNF-α and IL-17A. This study provides an innovative route for using SnoopLigase to realize a highly efficient generation of C-C-linked bis-Nbs. The approach can be applied to different and multicomponent systems for their potential applications in disease diagnosis and treatment.

Facile calcium ion-regulated grafting of dense and highly stretched hyaluronan for selective mediation of cancer cells rolling under high-speed flow

The development of materials that selectively mediate the rolling of cancer cells is important for the high-throughput enrichment of high-speed cancer cells. Here we constructed a dense and stretched low molecular weight hyaluronic acid (HA_9.6k)-modified surface to selectively promote the rolling of CD44-high cancer cells. The HA surface (calcium ion-regulated HA_9.6k surface, Ca-rHA) was fabricated via a calcium ion-regulated method, where calcium ion incorporation induced the shrink of HA_9.6k chains to achieve the highest reported grafting density of about 2.73 ± 0.20 × 10⁴ HA chains μm^-2. Upon the removal of calcium ions, the dense HA_9.6k chains switched to a highly stretched conformation. The high density and flexibility of Ca-rHA bearing abundant binding sites enhanced the rolling of CD44-high cancer cells and reduced the velocity of cells from 1389 µm s^-1 to 99 µm s^-1 (7%), comparable to that of the physiological rolling event and outperforming traditional grafting-to HA and E-selectin, without causing phenotypic changes. When processing complex samples under high-speed flow, Ca-rHA selectively mediated the rolling of cancer cells and enriched their ratio to peripheral blood mononuclear cells from 1:1 to 15:1. As the only reported artificial biomaterial capable of selectively mediating the rolling of cancer cells under a physiological high-speed flow, Ca-rHA holds promise in enriching intact cells for downstream analysis in the clinics by encouraging the surface-cell contacts. STATEMENT OF SIGNIFICANCE: The development of materials that selectively mediate the rolling of cancer cells is important for the high-throughput enrichment of cancer cells rolling under high-speed flow, yet is less reported. To selectively promote the rolling of cancer stem cell marker CD44-high cancer cells, a surface with dense and stretched low molecular weight hyaluronic acid (HA_9.6k) was constructed. With Ca²⁺ regulation, HA_9.6k chains shrank to achieve the highest reported grafting density of 2.73 ± 0.20 × 10⁴ chains μm^-2 and further switched to a highly stretched conformation after the removal of Ca²⁺ ions. As the only reported artificial biomaterial capable of selectively mediating the rolling of cancer cells under a physiological high-speed flow, this Ca²⁺-regulated HA_9.6k surface holds promise in enriching intact cells for downstream analysis in the clinics.

Micromorphological leaf epidermal traits as potential taxonomic markers for infrageneric classification of Oxytropis (Fabaceae)

The characteristics of the leaf epidermis have proven to be useful criteria to support taxonomic studies within Fabaceae. However, there are few systematic studies on the taxonomic significance of leaf epidermis of Oxytropis DC. Here, we used light and scanning electron microscopy to investigate leaf epidermal characteristics of 18 species of genus Oxytropis from the Northeastern Margin of Qinghai-Tibet Plateau. Our examination showed two main types of leaf epidermal cells: polygonal and irregular, and four different patterns of anticlinal walls: straight-arched, sinuolate, undulate, and sinuate. All species studied possess anomocytic stomata. Two trichome shapes were identified: strip-like trichomes, that were present only in O.ciliata, and cylindrical trichomes, present in all other species. Epidermal cell shape and anticlinal wall pattern were constant within species and are useful for species delimitation within genus Oxytropis, when combined with other macroscopic traits. The shape of trichomes can be useful for distinguishing O.ciliata from the other investigated species. Stomatal type was the same within the genus and may be used to elaborate the phylogenetic relationships between genera in combination with data on stomata from other genera. Cluster analysis results were largely consistent with the classification of species and sections based on macro morphological data, indicating that foliar epidermis characteristics of Oxytropis can be used as markers for taxonomic identification at the infrageneric classification level. Lastly, our results support the delineation of the section Leucopodia as an independent section but do not support the merging of section Gobicola into section Baicalia.

[Progress in epidemiological research of norovirus infection]

With characteristics of high infectivity, diverse transmission routes and high variation, norovirus is the main pathogen of sporadic cases and outbreaks of acute gastroenteritis, resulting in a serious disease burden. This paper summarizes the latest progress in epidemiological research of norovirus infection from aspects of disease burden caused by acute gastroenteritis, virus variation and predominant strains, prevention and control measures, and immunization and vaccine development.

The involvement of extracellular ATP in regulating the stunted growth of Arabidopsis plants by repeated wounding

BACKGROUND

Extracellular ATP (exATP) has been shown to act as a signal molecule for regulating growth, development, and responses of plants to the external environment.

RESULTS

In this study, we investigated the possible involvement of exATP in regulating the stunted growth caused by repeated wounding. The present work showed that the repeated wounding caused the decreases in leaf area, fresh weight, dry weight, and root length of Arabidopsis seedlings, while the exATP level was enhanced by the repeated wounding. Repeated application of exogenous ATP had similar effects on the plant growth, as the repeated wounding. Through the comparison of p2k1-3 mutant (in which T-DNA disrupted the gene coding P2K1, as exATP receptor) and wide type (WT) plants, it was found that the mutation in P2K1 decreased the sensitivity of plant growth to the repeated wounding and exogenous ATP application. Further works showed that the ibuprofen (IBU, an inhibitor of jasmonate biosynthesis) partially rescued the wound-induced growth degradation. In comparison, the P2K1 mutation partly rescued the wound-induced growth degradation, whereas this mutation failed to do so in the wounded seedlings treated with IBU, indicating that the role of exATP in regulating the growth degradation by repeated wounding could be linked to the JA signaling pathway.

CONCLUSIONS

In conclusion, these results indicate that exATP could be a regulator for the stunted growth of plants by repeated wounding.

Microbial synthesis of long-chain α-alkenes from methanol by engineering Pichia pastoris

α-Alkenes (terminal alkenes) are important fuel and platform chemicals that are mainly produced from petroleum. Microbial synthesis might provide a sustainable approach for α-alkenes. In this work, we engineered the methylotrophic yeast Pichia pastoris to produce long-chain (C15:1, C17:1 and C17:2) α-alkenes via a decarboxylation of fatty acids. Combinatorial engineering, including enzyme selection, expression optimization and peroxisomal compartmentalization, enabled the production of 1.6 mg/L α-alkenes from sole methanol. This study represents the first case of α-alkene biosynthesis from methanol and also provides a reference for the construction of methanol microbial cell factories of other high-value chemicals.

[Benefits and risks of prolonged dual antiplatelet therapy after percutaneous coronary intervention with drug-eluting stent in patients with stable coronary artery disease and diabetes]

Objective: To compare the efficacy and safety of prolonged dual antiplatelet therapy (DAPT>1 year) in patients with stable coronary artery disease (CAD) and diabetes who were event-free at 1 year after percutaneous coronary intervention (PCI) with drug-eluting stent (DES) in a large and contemporary PCI registry. Methods: A total of 1 661 eligible patients were selected from the Fuwai PCI Registry, of which 1 193 received DAPT>1 year and 468 received DAPT ≤1 year. The primary endpoint was major adverse cardiac and cerebrovascular event (MACCE) and Bleeding Academic Research Consortium (BARC) type 2, 3 or 5 bleeding, MACCE was defined as a composite of all-cause death, myocardial infarction or stroke. Multivariate Cox regression analysis and inverse probability of treatment weighting (IPTW) Cox regression analysis were performed. Results: After a median follow-up of 2.5 years, patients who received DAPT>1 year were associated with lower risks of MACCE (1.4% vs. 3.2%; hazard ratio (HR) 0.412, 95% confidence interval (CI) 0.205-0.827) compared with DAPT ≤1 year, which was primarily caused by the lower all-cause mortality (0.1% vs. 2.6%; HR 0.031, 95%CI 0.004-0.236). Risks of cardiac death (0.1% vs. 1.5%; HR 0.051, 95%CI 0.006-0.416) and definite/probable ST (0.3% vs. 1.1%; HR 0.218, 95%CI 0.052-0.917) were also lower in patients received DAPT>1 year than those received DAPT ≤ 1 year. No difference was found between the two groups in terms of BARC type 2, 3, or 5 bleeding (5.3% vs. 4.1%; HR 1.088, 95%CI 0.650-1.821). Conclusions: In patients with stable CAD and diabetes who were event-free at 1 year after PCI with DES, prolonged DAPT (>1 year) provides a substantial reduction in ischemic cardiovascular events, including MACCE, all-cause mortality, cardiac mortality, and definite/probable ST, without increasing the clinically relevant bleeding risk compared with ≤ 1-year DAPT. Further well-designed, large-scale randomized trials are needed to verify the beneficial effect of prolonged DAPT in this population.

[Etiological and epidemiological characteristics of Vibrio cholerae in Beijing, 2015-2021]

Objective: To analyze the etiological and epidemiological characteristics of Vibrio cholerae in Beijing during 2015-2021 and provide evidence for the prevention and control of cholera. Methods: The V. cholerae strains isolated in Beijing during 2015-2021 were analyzed by serotyping and virulence genes detection. Pulsed field gel electrophoresis (PFGE) was performed for the molecular typing of the strains. Based on the collected epidemiological and clinical data of cholera cases,the epidemiological characteristics of cholera were analyzed by descriptive epidemiology method. Results: A total of 76 Vibrio cholerae O1 strains were isolated in Beijing during 2015-2021, including 61 strains from human, 10 strains from environment and 5 strains from seafood. The 76 strains consisted of 68 Ogawa strains and 8 Inaba strains. Six Ogawa strains isolated from sporadic cases carried ctxAB. After NotⅠ digestion, 76 strains were divided into 33 PFGE patterns. From 2015 to 2021, a total of 38 cholera epidemics were reported in Beijing, most of them were sporadic ones, accounting for 92.11% (35/38). A total of 45 cases were reported, and the cases occurred during June-September accounted for 97.78% (44/45). Cholera cases occurred in 9 districts of Beijing, and the cases reported in Chaoyang district accounted for 42.22% (19/45) and in Changping district accounted for 31.11% (14/45). The age of the cholera cases ranged from 19 to 63 years. Except for one case with unknown clinical symptoms, 44 cases had diarrhea symptoms with 84.09% (37/44) of the cases reporting diarrhea (3-9 times/day), followed by yellow watery stool (95.45%, 42/44), abdominal pain (68.18%, 30/44), nausea and vomiting (40.91%, 18/44) and fever (36.36%, 16/44). Conclusion: Vibrio cholerae strains isolated in Beijing during 2015-2021 were mainly O1 serotype Ogawa,most of which were non-toxigenic. The PFGE of the strains varied. Cholera epidemics occurred in 9 districts of Beijing, but most were sporadic ones with incidence peak during June-September.

Single and dual functionalization of proteins using site-specific nucleophilic carbon ligations

We here found that while Meldrum's acid as the reactive warhead allows for the attachment of a single chemical modification on aldehyde-containing proteins, pyrazolone derivatives in combination with a phosphine nucleophile enable protein dual site-specific conjugation with the same or distinct moieties. These reactions are efficient and convergent under biocompatible conditions and allow access to protein bioconjugates with superior stability, homogeneity and flexibility. Our work expands the repertoire of bioconjugation chemistries and offers opportunities to construct bioconjugates with defined structure that have potential for medical and biomaterial applications.

Tyrosine-Based Dual-Functional Interface for Trapping and On-Site Photo-Induced Covalent Immobilization of Proteins

Tyrosine, a simple and well-available natural amino acid, is featured by the small size of the compound that contains multiple reactive groups. This study developed an efficient bioconjugation strategy using tyrosine-based dual-functional interfaces. When tyrosine molecules are immobilized on the surface of a supporting material through amino groups, their carboxyl groups can function as an attracting trap due to their anionic nature at neutral pH and ability to chelate nickel(II) ions (Ni²⁺), allowing the capture and enrichment of cationic proteins and histidine (His)-tagged proteins on the surface. The trapped proteins can be further covalently immobilized on site through ruthenium-mediated photochemical cross-linking, which has been found to be highly efficient and can be completed within minutes. This strategy was successfully applied to two different material systems. We found that tyrosine-modified agarose beads had a binding capacity of the His-tagged enhanced green fluorescent protein comparable to that of commonly used nitrilotriacetic acid-based resins, and further covalent coupling via dityrosine cross-linking achieved a yield of 85% within 5 min, without compromising much on its fluorescence activity. On the surface of tyrosine-modified 316L stainless steel, lysozyme was captured through electrostatic interaction and further immobilized. The resultant surface exhibited remarkable antibacterial activity against both Staphylococcus aureus and Escherichia coli. Such a tyrosine-based capture-then-coupling method is featured by its simplicity, high coupling efficiency, and high utilization rate of target molecules, making it particularly suitable for the proteins that are highly priced or vulnerable to general immobilization chemistry.

[Epidemiological characteristics of imported COVID-19 cases in Beijing]

Objective: To analyze the epidemiological characteristics of imported COVID-19 cases and the effect of vaccination on virus load and disease severity of the cases in Beijing. Methods: The data of the imported COVID-19 cases in Beijing were collected from the National Notifiable Infectious Disease Reporting System of China Information for Disease Control and Prevention and Epidemiology investigation. The data were processed and analyzed by Excel 2010 and SPSS 22.0. Results: From June 1 to September 30, 2021, a total of 171 imported COVID-19 cases were reported in Beijing, of which 66.67% (114/171) were asymptomatic. The cases were mainly from the Philippines, the United Arab Emirates, the United Kingdom and the Russian Federation, accounting for 67.84% (116/171). The male to female ratio of the cases was 2∶1 (114∶57). The median age M (Q₁, Q₃) of the cases was 28 (23, 36) years. The cases of Chinese accounted for 80.12% (137/171). The sequencing of the whole genome of the virus in 47 imported COVID-19 cases showed that the proportion of Delta variant was 76.60% (36/47). The COVID-19 vaccination coverage rate in the cases was 60.82% (104/171), but the full vaccination coverage rate was 53.80% (92/171). In the imported COVID-19 cases, 13.53% (23/170) were screened to be SARS-CoV-2 nucleic acid positive on the day when they arrived in Beijing, and all the cases were positive for 2019-nCoV nucleic acid within 28 days. The severity of the disease was higher in the unvaccinated group than in the partially vaccinated group and fully vaccinated group (P<0.001). In the unvaccinated group, there were 1 severe case and 1 critical case. The median Ct values M (Q₁, Q₃) of N gene and ORFlab gene in unvaccinated group were 32.51 (23.23, 36.06) and 32.78 (24.00, 36.38), respectively. There was no significant difference in the median of double-gene Ct value between the partially vaccinated group and the fully vaccinated group. Conclusions: During the study period, most of the imported COVID-19 cases in Beijing were asymptomatic. No matter vaccinated or not, the viral loads in the COVID-19 cases were similar, but the vaccination could reduce the severity of the disease.

Increased clearance of indoxyl sulphate in renal failure rats with the addition of water-soluble poly-β-cyclodextrin to the dialysate

AIM

Indoxyl sulphate (IS), a protein-bound uremic toxin that dramatically increases in the sera of patients with end-stage renal disease (ESRD), is poorly removed by conventional haemodialysis (HD). The purpose of this study was to explore whether the addition of water-soluble sorbent poly-β-cyclodextrins (PCDs) to dialysate can increase the clearance of IS in uremic rats in vivo.

METHODS

Male SD rats (450-550 g, n = 18) with nephrectomy plus IS injection (10-mg/kg) were randomly divided into three groups: 1. The HD group (n = 6): conventional HD for 4 h; 2. the 2% PCD group: 2% PCD added to the dialysate, HD for 4 h; and 3. the 4% PCD group: 4% PCD added to the dialysate, HD for 4 h. The serum IS levels in model rats were similar to those of ESRD patients. A stable and safe rat HD treatment mode was established by adjusting the vascular access, blood flow rate, dialysate flow rate, dialysis pipe, dialysate configuration, temperature, treatment environment, and other aspects.

RESULTS

Our study found that adding 2% PCD to dialysate significantly improved the clearance of IS approximately twofold compared with conventional HD. Further increasing the PCD concentration to 4% did not increase IS clearance.

CONCLUSION

Therefore, our study showed that adding water-soluble sorbent PCDs to dialysate significantly improved the clearance of IS in uremic rats in vivo.

Nanobodies: From Serendipitous Discovery of Heavy Chain-Only Antibodies in Camelids to a Wide Range of Useful Applications

The presence of unique heavy chain-only antibodies (HCAbs) in camelids was discovered at Vrije Universiteit Brussel (VUB, Brussels, Belgium) at a time when many researchers were exploring the cloning and expression of smaller antigen-binding fragments (Fv and Fab) from hybridoma-derived antibodies. The potential importance of this discovery was anticipated, and efforts were immediately undertaken to understand the emergence and ontogeny of these HCAbs as well as to investigate the applications of the single-domain antigen-binding variable domains of HCAbs (nanobodies). Nanobodies were demonstrated to possess multiple biochemical and biophysical advantages over other antigen-binding antibody fragments and alternative scaffolds. Today, nanobodies have a significant and growing impact on research, biotechnology, and medicine.

Extracellular ATP is involved in regulating Arabidopsis seed germination

Extracellular ATP level induced a transient increase during germination of Arabidopsis seeds, and extracellular ATP could negatively regulate the seed germination by its receptor, DORN1. Extracellular ATP (exATP) acts as a signal molecule for regulating growth, development, and responses of plants to external environments. In this study, we investigated the possible involvement of exATP in regulating the seed germination of Arabidopsis thaliana. Treatments of Arabidopsis seeds with exogenous ATP delayed seed germination, suggesting that exATP could be a repressor for seed germination. During the germination of Arabidopsis seeds, the exATP level of the seeds presented a transient increase. When exogenous application of the glucose-hexokinase system effectively decreased the exATP level of the Arabidopsis seeds during germination, the percentage of germination was significantly enhanced, while the products of ATP hydrolysis had no effects on the germination. Further studies showed that the seeds of dorn 1-3 mutant plants (mutation in exATP receptor) showed a higher germination percentage, compared to the seeds of wide type (WT) plants. In addition, the dorn 1-3 mutant seeds were less sensitive to the delay-effect of exogenous ATP on seed germination than the WT seeds. The dorn 1-3 mutant seeds presented a higher GA (gibberellin) content, lower ABA (abscisic acid) content, and lower ratio of ABA/GA contents before the imbibition, compared to the WT seeds. The regulation of seed germination by exATP was dependent on the external temperature. These data suggest that exATP is involved in regulating Arabidopsis seed germination.

[Epidemiological characteristics of hand, foot and mouth disease among people aged 6 and over in Beijing, 2011-2020]

Objective: To analyze the epidemiological characteristics of hand, foot and mouth disease (HFMD) among people ≥6 years old in Beijing from 2011 to 2020. Methods: The incidence data of HFMD cases from 2011 to 2020 were collected from the National Notifiable Infectious Disease Reporting System of China Information for Disease Control and Prevention and the etiological surveillance of HFMD in 29 sentinel hospitals from 16 districts of Beijing. Descriptive epidemiological methods were used to analyze the distributions, pathogen constituents, and changes of HFMD cases in Beijing people ≥6 years old. Results: From 2011 to 2020, a total of 38 183 cases of HFMD were reported among people ≥6 years old in Beijing, of which 46 (0.12%) cases were severe. The average annual reported incidence was 19.04/100 000. The ratio of males to females were 1.37∶1(22 064∶16 119). The proportion of HFMD in people ≥6 years old increased from 7.56%(2 606/34 488) in 2011 to 24.54% (546/2 225) in 2020. The average incidence of HFMD was higher in Shunyi district, Yanqing district, and Tongzhou district than in other districts in Beijing. The positive rate of enterovirus in sentinel surveillance was 66.78% (1 976/2 959), the proportion of enterovirus group A 71 (EV-A71) was 45.29% (101/223) in 2014, no EV-A71 positive was detected in 2020, and the proportion of Coxsackievirus A 6 (CV-A6) increased from 15.11% (34/225) in 2016 to 81.08% (60/74) in 2020. Conclusions: From 2011 to 2020, the proportion of cases with HFMD in people ≥6 years old in Beijing increased yearly, and the proportion of EV-A71 positive patients decreased basically. Since 2016, CV-A6 has gradually become the dominant pathogen. More attention should be paid to the epidemic situation and dynamic pathogen changes of hand foot mouth disease in people ≥6 years old.

Leptin Aggravates Periodontitis by Promoting M1 Polarization via NLRP3

Periodontitis is characterized by periodontal pocket formation, loss of attachment, and alveolar bone resorption. Both innate and adaptive immunity are involved in the pathogenesis of this oral chronic inflammatory disease. Accumulating evidence indicates a critical role of leptin in periodontal diseases. However, the mechanism by which leptin promotes periodontitis pathogenesis remains unclear. In the present study, we observed an elevated expression of leptin in the serum of periodontitis mice compared to that in healthy controls. There was a higher extent of M1 phenotype macrophage infiltration in mice periodontitis samples than in healthy controls. A positive correlation was observed between the serum leptin levels and M1 macrophages. Treatment with leptin increased M1 macrophage polarization and decreased M2 macrophage polarization in RAW 264.7 cells. Moreover, leptin facilitated lipopolysaccharide (LPS)-induced M1 phenotype macrophage polarization in RAW 264.7 cells. In bone marrow-derived macrophages (BMDMs) generated from leptin-deficient obese (ob/ob) mice, M1 macrophage polarization was significantly attenuated after LPS stimulation compared to the healthy controls. With regards to the molecular mechanism, we found that leptin activated the NOD-like receptor family pyrin domain containing 3 (NLRP3) inflammasome and promoted M1 polarization via the NLRP3 inflammasome in vitro. In BMDMs generated from Nlrp3^-/- mice, M1 macrophage polarization was significantly attenuated after synchronous stimulation with leptin and LPS compared with BMDMs produced by healthy controls. The NLRP3 inhibitor MCC950 also prevented leptin-mediated M1 macrophage polarization in RAW 264.7 cells. Nlrp3^-/- periodontitis models indicated that leptin aggravates the periodontal response to the ligature by promoting M1 macrophage polarization via the NLRP3 inflammasome. Taken together, we show that leptin promotes the progression of periodontitis via proinflammatory M1 macrophage skewing, and targeting leptin/NLRP3 signaling may be a feasible approach for treating periodontitis.

Three-dimensional Quantification of Enamel Preservation in Tooth Preparation for Porcelain Laminate Veneers: A Fully Digital Workflow In Vitro Study

OBJECTIVE

This in vitro study aimed to evaluate the preservation of enamel after tooth preparation for porcelain laminate veneers (PLVs) at different preparation depths based on a fully digital workflow.

METHODS AND MATERIALS

Sixty extracted human maxillary anterior teeth, including 20 maxillary central incisors (MCIs), 20 maxillary lateral incisors (MLIs), and 20 maxillary canines (MCs) underwent microcomputed tomography (CT) scanning, and were reconstructed as three-dimensional (3D) enamel and dentin models. Subsequently, the three-dimensional (3D) enamel models were imported into Materialise, where each enamel model underwent seven types of virtual preparation for PLVs at preparation depths at 0.1-mm increments from 0.1-0.3-0.5 mm (D1) to 0.7-0.9-1.1 mm (D7). The enamel surface was depicted by merging the virtual preparation and, respective, dentin models. The enamel area and prepared surface were measured to calculate the percentage of enamel (R%). The data were statistically analyzed using one-way analysis of variance (ANOVA) (α=0.05).

RESULTS

The group-wise mean (standard deviation) R values for the MCIs were as follows: D1-D3: 100.00 (0) each, and D4-D7: 74.70 (2.45), 51.40 (5.12), 24.40 (3.06), and 0.00 (0), respectively. The group-wise mean R values for the MLIs were 100.00 (0), 73.70 (3.40), 53.50 (3.44), 25.20 (3.79), and 0.90 (0.99) for the D1-D5 groups, respectively; and 0.00 (0) each for the D6-D7 groups. The group-wise mean (standard deviations) R values for the MCs were as follows: D1-D3: 100.00 (0) each, and D4-D7: 99.00 (1.34), 77.10 (3.28), 74.20 (3.61), and 52.20 (4.09), respectively. The one-way ANOVA revealed significant differences between the seven groups in the MCIs, MLIs, and MCs (p<0.05).

CONCLUSIONS

Our results recommended preparation depths of up to 0.3-0.5-0.7 mm (MCIs), 0.1-0.3-0.5 mm (MLIs), and 0.4-0.6-0.8 mm (MCs) to facilitate complete intraenamel preparation. Moreover, 50% enamel was preserved at preparation depths of 0.5-0.7-0.9 mm (MCIs), 0.3-0.5-0.7 mm (MLIs), and 0.7-0.9-1.1 mm (MCs).

Nanobody as solubilization chaperone for the expression and purification of inclusion-body prone proteins

Here we report a new protocol for enhancing the soluble expression of inclusion body (IB)-prone proteins in E. coli using nanobody (Nb) as a molecular-specific chaperone. The specific intracellular binding...

Cytoplasmic Expression of Nanobodies with Formylglycine Generating Enzyme Tag and Conversion to a Bio-Orthogonal Aldehyde Group

Nanobodies (Nbs) can be successfully retrieved following phage, bacterial, yeast, or ribosome display of immune, synthetic, or naïve libraries. However, after panning, multiple individual Nb clones need to be screened and assessed for solubility, antigen specificity, affinity, and potential biological function. Therefore, it is highly desirable to have a convenient expression strategy to obtain sufficient protein for in-depth characterization of the Nbs. The presence of a purification and detection tag, as well as a chemically reactive group to enable simple generation of Nb derivatives, would be of great help in this regard. Here, we provide a general protocol for high yield cytoplasmic expression and purification of formylglycine generating enzyme (FGE)-tagged Nbs. The cysteine within the FGE tag is easily converted to formylglycine by passing the FGE-tag containing Nb over a continuous-flow bio-catalysis system. The aldehyde group within the formylglycine side chain at the C-terminal end of the Nb is suitably located for subsequent bio-orthogonal reactions to fluorescent dyes, biotin, polyethylene glycol, or chromatography resins. We also include methods for production of high yield recombinant FGE, as well as conditions for its immobilization on Sepharose to produce the continuous-flow bio-catalysis system.

Ultrasound Assessment of Plaque Characteristics to Predict Re-occlusion after Surgical Treatment of Internal Carotid Artery Occlusion

The purpose of this study was to explore the relationship between plaque characteristics and re-occlusion after surgical treatment of internal carotid artery occlusion (ICAO). From January 2015 to January 2021, 177 patients with ICAO underwent surgery. Eighty-five cases were included in the study, and in 13 of them, re-occlusion occurred within 6 mo after surgery treatment (13/85, 15.85%). The calcification at the base of the plaque was longer in the re-occlusion group than in the non-occlusion group (10.70 ± 4.22 mm vs. 7.15 ± 1.41 mm, p = 0.001). Multivariate regression analysis revealed that the length of calcification at the base of the plaque was an independent risk factor for postoperative re-occlusion (odds ratio [OR]: 1.414, 95% confidence interval [CI]: 1.078-1.855, p = 0.012). The cutoff value for the length of calcification at the base of the plaque predicting re-occlusion after ICAO was 8.5 mm (95% CI: 0.700-0.962, p = 0.001). The area under the receiver operating characteristic curve was 0.831. Sensitivity and specificity were 70% and 80.9%, respectively. These results indicate that pre-operative ultrasound examination of the length of calcification at the base of the plaque could predict re-occlusion after surgical treatment of ICAO.

Nanobody-loaded immunosorbent for highly-specific removal of interleukin-17A from blood

Elimination of overproduced cytokines from blood can relieve immune system disorders caused by hypercytokinemia. Due to the central roles of interleukin-17A (IL-17A) plays in regulating the immunity and inflammatory responses in humans, here, a novel immunosorbent containing anti-IL-17A nanobodies (Nbs) was constructed for IL-17A removal from blood. The theoretical maximum adsorption capacity estimated from the Langmuir isotherm is up to 11.55 mg/g gel, which is almost consistent with the saturated adsorption capacity determined in dynamic adsorption. The in vitro plasma perfusion test demonstrated a remarkable adsorptive performance of the Nb-coupled sorbent since more than 75% IL-17A could be eliminated under the plasma/sorbent ratio of 1000:1. These results indicated the Nb-loaded immunosorbent can provide a simple and economic platform technology for immunoaffinity depletion of single or even multiple cytokines from plasma.