[Preliminary study of Ilizarov technique in treatment of lower limb deformity caused by achondroplasia].

Objective: To investigate the surgical method and preliminary effectiveness of Ilizarov technique in the treatment of lower limb deformity caused by achondroplasia. Methods: The clinical data of 38 patients with lower limb deformity caused by achondroplasia treated by Ilizarov technique between February 2014 and September 2021 were retrospectively analyzed. There were 18 males and 20 females, the age ranged from 7 to 34 years, with an average of 14.8 years. All patients presented with bilateral knee varus deformity. The preoperative varus angles was (15.2±4.2)°, and knee society score (KSS) was 61.8±7.2. Nine of these patients underwent tibia and fibula osteotomy, 29 cases underwent tibia and fibula osteotomy and bone lengthening at the same time. Full-length bearing position X-ray films of bilateral lower limbs were taken to measure the bilateral varus angles, analyze the healing index, and record the occurrence of complications. KSS score was used to evaluate the improvement of knee joint function before and after operation. Results: All 38 cases were followed up 9-65 months, with an average of 26.3 months. Needle tract infection occurred in 4 cases and needle tract loosening occurred in 2 cases after operation, which were improved after symptomatic treatment such as dressing change, Kirschner wire change, and oral antibiotics, and no neurovascular injury occurred in all patients. The external fixator was worn for 3-11 months after operation, with an average of 7.6 months, and the healing index was 43-59 d/cm, with an average of 50.3 d/cm. At last follow-up, the leg was 3-10 cm longer, with an average of 5.5 cm. The varus angles was (1.5±0.2)° and the KSS score was 93.7±2.6, which significantly improved when compared with those before operation ( P<0.05). Conclusion: Ilizarov technique is a safe and effective method for the treatment of short limb with genu varus deformity caused by achondroplasia, which can improve the quality of life of patients.

Long-term passaging of pseudo-typed SARS-CoV-2 reveals the breadth of monoclonal and bispecific antibody cocktails.

The continuous emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants poses challenges to the effectiveness of neutralizing antibodies. Rational design of antibody cocktails is a realizable approach addressing viral immune evasion. However, evaluating the breadth of antibody cocktails is essential for understanding the development potential. Here, based on a replication competent vesicular stomatitis virus model that incorporates the spike of SARS-CoV-2 (VSV-SARS-CoV-2), we evaluated the breadth of a number of antibody cocktails consisting of monoclonal antibodies and bispecific antibodies by long-term passaging the virus in the presence of the cocktails. Results from over two-month passaging of the virus showed that 9E12 + 10D4 + 2G1 and 7B9-9D11 + 2G1 from these cocktails were highly resistant to random mutation, and there was no breakthrough after 30 rounds of passaging. As a control, antibody REGN10933 was broken through in the third passage. Next generation sequencing was performed and several critical mutations related to viral evasion were identified. These mutations caused a decrease in neutralization efficiency, but the reduced replication rate and ACE2 susceptibility of the mutant virus suggested that they might not have the potential to become epidemic strains. The 9E12 + 10D4 + 2G1 and 7B9-9D11 + 2G1 cocktails that picked from the VSV-SARS-CoV-2 system efficiently neutralized all current variants of concern and variants of interest including the most recent variants Delta and Omicron, as well as SARS-CoV-1. Our results highlight the feasibility of using the VSV-SARS-CoV-2 system to develop SARS-CoV-2 antibody cocktails and provide a reference for the clinical selection of therapeutic strategies to address the mutational escape of SARS-CoV-2.

Tryptophan-Modulated Nanoscale Metal-Organic Framework for Coordinated Loading of Biomolecules for Cascade Production of Reactive Oxygen and Nitrogen Species.

Owing to the high surface area and porosity, metal-organic frameworks (MOFs) could be utilized as both nanocarriers of biopharmaceuticals and nanoreactors to organize cascade biological reactions with great potential in cancer treatment. However, nanoscale MOFs suitable for biomedical applications rely on harsh preparation conditions. Here, we utilized tryptophan to modulate the morphology and optical properties of zeolitic imidazolate framework-8 (ZIF-8) as nanocarrier to efficiently encapsulate the enzyme and mRNA. Under room temperature in an aqueous solution, tryptophan would coordinate with zinc ions to form ZIF-8:Trp with a decreased size from the µm range to sub-200 nm. In addition, cargo release could be monitored in real time via fluorescence red-shift effects. Besides being used as nanocarriers of biomolecules, ZIF-8:Trp could also be utilized as nanoreactors to induce cascade reactions to produce reactive oxygen and nitrogen species. Overall, this nanosized ZIF-8:Trp could provide a new strategy for preparation of cascade bioreactions and provide new insight for gas therapy.

Broad ultra-potent neutralization of SARS-CoV-2 variants by monoclonal antibodies specific to the tip of RBD.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) continue to wreak havoc across the globe. Higher transmissibility and immunologic resistance of VOCs bring unprecedented challenges to epidemic extinguishment. Here we describe a monoclonal antibody, 2G1, that neutralizes all current VOCs and has surprising tolerance to mutations adjacent to or within its interaction epitope. Cryo-electron microscopy structure showed that 2G1 bound to the tip of receptor binding domain (RBD) of spike protein with small contact interface but strong hydrophobic effect, which resulted in nanomolar to sub-nanomolar affinities to spike proteins. The epitope of 2G1 on RBD partially overlaps with angiotensin converting enzyme 2 (ACE2) interface, which enables 2G1 to block interaction between RBD and ACE2. The narrow binding epitope but high affinity bestow outstanding therapeutic efficacy upon 2G1 that neutralized VOCs with sub-nanomolar half maximal inhibitory concentration in vitro. In SARS-CoV-2, Beta or Delta variant-challenged transgenic mice and rhesus macaque models, 2G1 protected animals from clinical illness and eliminated viral burden, without serious impact to animal safety. Mutagenesis experiments suggest that 2G1 is potentially capable of dealing with emerging SARS-CoV-2 variants in the future. This report characterized the therapeutic antibodies specific to the tip of spike against SARS-CoV-2 variants and highlights the potential clinical applications as well as for developing vaccine and cocktail therapy.

[Clinical observation of accordion technique in promoting bone transport and prolonging newborn bone mineralization].

OBJECTIVE: To analyze effect of accordion technique on bone mineralization of extended bone segment in treating tibial bone defect with bone transport. METHODS: From May 2017 to October 2019, 22 patients with tibial bone defects were treated with Ilizarov bone-transport technique, and divided into two groups after bone-transport was completed, 11 patients in each group. In observation group, there were 9 males and 2 females aged from 20 to 60 years old with an average of (42.6± 13.3) years old;the length of bone defect ranged from 3 to 13 cm with an average of(6.4±2.6) cm;2 patients were suffered from upper tibial bone defects, 3 patients were middle and 6 patients were lower;patients were treated with accordion technique for 35 days. In control group, there were 10 males and 1 female aged from 41 to 60 years old with an average of (51.6±6.4) years old;the length of bone defect ranged from 3 to 10.7 cm with an average of (6.6±2.5) cm;1 patient was suffered from upper tibial bone defects, 3 patients were middle and 7 patients were lower;patients were treated with lock external fixator to waiting bone mineralization. The content of hydroxyapatite (HAP) extended bone segment was measured after bone-transport completed immediately, 35, 65 and 95 days after bone-transport was completed, respectively, then the mineralization time and healing time were compared between two groups, and the therapeutic effect of bone defect was evaluated by using Paley scoring criteria. RESULTS: Twenty-two patients were followed up from 18 to 36 months with an average of (27.0±6.3) months. The wounds on the bone defects healed spontaneously during bone transport, and there were no wound complications such as skin infection or skin necrosis occurred. There were statisticaldifference in the content of HAP of the extended bone segments at 35, 65 and 95 days after bone-transport between two groups (P<0.05). There were difference in mineralization time and healing time between two groups (P<0.05). According to Paley standard evaluation, 10 patients got excellent results, and 1 good in observation group; while 9 patients got excellent results, 2 good in control group;and there was no differences between two groups (Z=-0.607, P= 0.544). CONCLUSION: Accordion technique and locking external fixator mineralization in prolonging bone segment healing after bone-transport have the equal clinical effect, while the accordion technique could significantly accelerate the growth rate of HAP and shorten the mineralization time and healing time.

Role of microRNA-335 carried by bone marrow mesenchymal stem cells-derived extracellular vesicles in bone fracture recovery.

Mesenchymal stem cells (MSCs) have the potential to reduce healing time and treat nonunion in fracture patients. In this study, bone marrow MSCs-derived extracellular vesicles (B-EVs) were firstly extracted and identified. CD9-/- and normal mice were enrolled for the establishment of fracture models and then injected with B-EVs. Osteoblast differentiation and fracture recovery were estimated. The levels of osteoblast-related genes were detected, and differentially expressed microRNAs (miRs) in B-EVs-treated normal fracture mice were screened and verified. The downstream mechanisms of miR were predicted and assessed. The loss-of functions of miR-335 in B-EV and gain-of-functions of VapB were performed in animal and cell experiments to evaluate their roles in bone fracture. Collectively, B-EVs promoted bone fracture recovery and osteoblast differentiation by releasing miR-335. miR-335 downregulation in B-EVs impaired B-EV functions in fracture recovery and osteoblast differentiation. miR-335 could target VapB, and VapB overexpression reversed the effects of B-EVs on osteoblast differentiation. B-EV treatment activated the Wnt/ß-catenin pathway in fracture mice and osteoblasts-like cells. Taken together, the study suggested that B-EVs carry miR-335 to promote bone fracture recovery via VapB and the Wnt/ß-catenin pathway. This study may offer insights into bone fracture treatment.

Topical Recombinant Human Epidermal Growth Factor for Diabetic Foot Ulcers: A Meta-Analysis of Randomized Controlled Clinical Trials.

Diabetic foot ulcer and its complications are becoming more and more serious problems threatening people's health. In the last decade, multiple growth factors and their combined applications have shown potentials in promoting the healing process of diabetic foot ulcers. The purpose of this study is to perform a meta-analysis of the efficacy and safety of topical recombinant human epidermal growth factor (rhEGF) on the treatment of diabetic foot ulcers. As of November 30, 2018, we had conducted a comprehensive review of PubMed, EMBASE, Cochrane Library databases, and Web of Science. Seven randomized controlled trials (RCTs) that involved 610 participants were included in this review. The pooled results showed that topical rhEGF could significantly promote the healing of diabetic foot ulcers (risk ratio [RR] 1.54, 95% confidence interval [CI] 1.30 to 1.83; I2 = 18%). Topical application of rhEGF could promote ulceration healing of diabetic feet of Wagner grade 1 or 2 significantly (RR, 1.61; 95% CI, 1.32 to 1.97; I2 = 0%), and intralesional injection of rhEGF appeared to promote the healing of more severe ulcers (RR, 2.06, 95%, CI 0.35 to 12.22; I2 = 50%). However, patients developed more shivering (RR, 4.67; 95% CI, 1.39 to 15.71; I2 = 0%), nauseas/vomiting (RR, 2.18; 95% CI, 0.72 to 6.55; I2 = 0%) in the group of intralesional injection of rhEGF compared with the control group, although these symptoms were not found with the topical application of rhEGF. No serious complications were found associated with topical rhEGF. Topical rhEGF treatment of diabetic foot ulcers has showed a broad application prospect, yet more relevant well-designed RCTs are needed in the future.

Synthesis and bioactivities study of new antibacterial peptide mimics: The dialkyl cationic amphiphiles.

The emergence of infectious diseases caused by pathogenic bacteria is widespread. Therefore, it is urgently required to enhance the development of novel antimicrobial agents with high antibacterial activity and low cytotoxicity. A series of novel dialkyl cationic amphiphiles bearing two identical length lipophilic alkyl chains and one non-peptidic amide bond were synthesized and tested for antimicrobial activities against both Gram-positive and Gram-negative bacteria. Particular compounds synthesized showed excellent antibacterial activity toward drug-sensitive bacteria such as S. aureus, E. faecalis, E. coli and S. enterica, and clinical isolates of drug-resistant species such as methicillin-resistant S. aureus (MRSA), KPC-producing and NDM-1-producing carbapenem-resistant Enterobacteriaceae (CRE). For example, the MIC values of the best compound 4g ranged from 0.5 to 2 µg/mL against all these strains. Moreover, these small molecules acted rapidly as bactericidal agents, and functioned primarily by permeabilization and depolarization of bacterial membranes. Importantly, these compounds were difficult to induce bacterial resistance and can potentially combat drug-resistant bacteria. Thus, these compounds can be developed into a new class of antibacterial peptide mimics against Gram-positive and Gram-negative bacteria, including drug-resistant bacterial strains.