Modular Access to Chiral Amines via Imine Reductase-Based Photoenzymatic Catalysis.

The development of catalysts serves as the cornerstone of innovation in synthesis, as exemplified by the recent discovery of photoenzymes. However, the repertoire of naturally occurring enzymes repurposed by direct light excitation to catalyze new-to-nature photobiotransformations is currently limited to flavoproteins and keto-reductases. Herein, we shed light on imine reductases (IREDs) that catalyze the remote C(sp3)-C(sp3) bond formation, providing a previously elusive radical hydroalkylation of enamides for accessing chiral amines (45 examples with up to 99% enantiomeric excess). Beyond their natural function in catalyzing two-electron reductive amination reactions, upon direct visible-light excitation or in synergy with a synthetic photoredox catalyst, IREDs are repurposed to tune the non-natural photoinduced single-electron radical processes. By conducting wet mechanistic experiments and computational simulations, we unravel how engineered IREDs direct radical intermediates toward the productive and enantioselective pathway. This work represents a promising paradigm for harnessing nature's catalysts for new-to-nature asymmetric transformations that remain challenging through traditional chemocatalytic methods.

Repurposing Visible-Light-Excited Ene-Reductases for Diastereo- and Enantioselective Lactones Synthesis.

Repurposing enzymes to catalyze non-natural asymmetric transformations that are difficult to achieve using traditional chemical methods is of significant importance. Although radical C-O bond formation has emerged as a powerful approach for constructing oxygen-containing compounds, controlling the stereochemistry poses a great challenge. Here we present the development of a dual bio-/photo-catalytic system comprising an ene-reductase and an organic dye for achieving stereoselective lactonizations. By integrating directed evolution and photoinduced single electron oxidation, we repurposed engineered ene-reductases to steer non-natural radical C-O formations (one C-O bond for hydrolactonizations and lactonization-alkylations while two C-O bonds for lactonization-oxygenations). This dual catalysis gave a new approach to a diverse array of enantioenhanced 5- and 6-membered lactones with vicinal stereocenters, part of which bears a quaternary stereocenter (up to 99% enantiomeric excess, up to 12.9:1 diastereomeric ratio). Detailed mechanistic studies, including computational simulations, uncovered the synergistic effect of the enzyme and the externally added organophotoredox catalyst Rh6G.

Rare germline mutation and MSH2-&MSH6 + expression in a double primary carcinoma of colorectal carcinoma and endometrial carcinoma: a case report.

BACKGROUND: Multiple primary malignancies are rare in cancer patients, and risk factors may include genetics, viral infection, smoking, radiation, and other environmental factors. Lynch syndrome (LS) is the most prevalent form of hereditary predisposition to double primary colorectal and endometrial cancer in females. LS, also known as hereditary nonpolyposis colorectal cancer (HNPCC), is a common autosomal dominant condition. Pathogenic germline variants in the DNA mismatch repair (MMR) genes, namely MLH1, MSH2, MSH6, and PMS2, and less frequently, deletions in the 3' end of EPCAM cause LS. It manifested itself as loss of MMR nuclear tumor staining (MMR protein deficient, dMMR). CASE PRESENTATION: This case study describes a double primary carcinoma in a 49-year-old female. In June 2022, the patient was diagnosed with highly to moderately differentiated endometrioid adenocarcinoma. The patient's mother died of esophageal cancer at age 50, and the father died of undefined reasons at age 70. Immunohistochemical stainings found ER (++), PR (++), P53 (+), MSH2 (-), MSH6 (+), MLH1 (+), and PMS2 (+). MMR gene sequencing was performed on endometrial tumor and peripheral blood samples from this patient. The patient carried two pathogenic somatic mutations in the endometrial tumor, MSH6 c.3261dupC (p.Phe1088LeufsTer5) and MSH2 c.445_448dup (p.Val150fs), in addition to a rare germline mutation MSH6 c.133G > C (p.Gly45Arg). Two years ago, the patient was diagnosed with moderately differentiated adenocarcinoma in the left-half colon. Immunohistochemical stainings found MSH2(-), MSH6(+), MLH1(+), and PMS2(+) (data not shown). CONCLUSIONS: In the case of a patient with double primary EC and CRC, a careful evaluation of the IHC and the genetic data was presented. The patient carried rare compound heterozygous variants, a germline missense mutation, and a somatic frameshift mutation of MSH6, combined with a novel somatic null variant of MSH2. Our study broadened the variant spectrum of double primary cancer and provided insight into the molecular basis for abnormal MSH2 protein loss and double primary carcinoma.

A light-driven enzymatic enantioselective radical acylation.

Enzymes are recognized as exceptional catalysts for achieving high stereoselectivities1-3, but their ability to control the reactivity and stereoinduction of free radicals lags behind that of chemical catalysts4. Thiamine diphosphate (ThDP)-dependent enzymes5 are well-characterized systems that inspired the development of N-heterocyclic carbenes (NHCs)6-8 but have not yet been proved viable in asymmetric radical transformations. There is a lack of a biocompatible and general radical-generation mechanism, as nature prefers to avoid radicals that may be harmful to biological systems9. Here we repurpose a ThDP-dependent lyase as a stereoselective radical acyl transferase (RAT) through protein engineering and combination with organophotoredox catalysis10. Enzyme-bound ThDP-derived ketyl radicals are selectively generated through single-electron oxidation by a photoexcited organic dye and then cross-coupled with prochiral alkyl radicals with high enantioselectivity. Diverse chiral ketones are prepared from aldehydes and redox-active esters (35 examples, up to 97% enantiomeric excess (e.e.)) by this method. Mechanistic studies reveal that this previously elusive dual-enzyme catalysis/photocatalysis directs radicals with the unique ThDP cofactor and evolvable active site. This work not only expands the repertoire of biocatalysis but also provides a unique strategy for controlling radicals with enzymes, complementing existing chemical tools.

The Versatile Biocatalyst of Cytochrome P450 CYP102A1: Structure, Function, and Engineering.

Wild-type cytochrome P450 CYP102A1 from Bacillus megaterium is a highly efficient monooxygenase for the oxidation of long-chain fatty acids. The unique features of CYP102A1, such as high catalytic activity, expression yield, regio- and stereoselectivity, and self-sufficiency in electron transfer as a fusion protein, afford the requirements for an ideal biocatalyst. In the past three decades, remarkable progress has been made in engineering CYP102A1 for applications in drug discovery, biosynthesis, and biotechnology. The repertoire of engineered CYP102A1 variants has grown tremendously, whereas the substrate repertoire is avalanched to encompass alkanes, alkenes, aromatics, organic solvents, pharmaceuticals, drugs, and many more. In this article, we highlight the major advances in the past five years in our understanding of the structure and function of CYP102A1 and the methodologies used to engineer CYP102A1 for novel applications. The objective is to provide a succinct review of the latest developments with reference to the body of CYP102A1-related literature.

Computational redesign of cytochrome P450 CYP102A1 for highly stereoselective omeprazole hydroxylation by UniDesign.

Cytochrome P450 CYP102A1 is a prototypic biocatalyst that has great potential in chemical synthesis, drug discovery, and biotechnology. CYP102A1 variants engineered by directed evolution and/or rational design are capable of catalyzing the oxidation of a wide range of organic compounds. However, it is difficult to foresee the outcome of engineering CYP102A1 for a compound of interest. Here, we introduce UniDesign as a computational framework for enzyme design and engineering. We tested UniDesign by redesigning CYP102A1 for stereoselective metabolism of omeprazole (OMP), a proton pump inhibitor, starting from an active but nonstereoselective triple mutant (TM: A82F/F87V/L188Q). To shift stereoselectivity toward (R)-OMP, we computationally scanned three active site positions (75, 264, and 328) for mutations that would stabilize the binding of the transition state of (R)-OMP while destabilizing that of (S)-OMP and picked three variants, namely UD1 (TM/L75I), UD2 (TM/A264G), and UD3 (TM/A328V), for experimentation, based on computed energy scores and models. UD1, UD2, and UD3 exhibit high turnover rates of 55 ± 4.7, 84 ± 4.8, and 79 ± 5.7 min-1, respectively, for (R)-OMP hydroxylation, whereas the corresponding rates for (S)-OMP are only 2.2 ± 0.19, 6.0 ± 0.68, and 14 ± 2.8 min-1, yielding an enantiomeric excess value of 92, 87, and 70%, respectively. These results suggest the critical roles of L75I, A264G, and A328V in steering OMP in the optimal orientation for stereoselective oxidation and demonstrate the utility of UniDesign for engineering CYP102A1 to produce drug metabolites of interest. The results are discussed in the context of protein structures.

[Effect of body mass index on short-term effectiveness of high tibial osteotomy in treatment of varus knee arthritis].

Objective: To investigate the effect of body mass index (BMI) on the short-term effectiveness of high tibial osteotomy (HTO) in the treatment of varus knee arthritis. Methods: The clinical data of 84 patients (84 knees) with varus knee arthritis treated with HTO between May 2016 and August 2020 were retrospectively analyzed. According to BMI, the patients were divided into normal group (32 patients in group A, BMI<25 kg/m 2), overweight group (27 patients in group B, BMI>30 kg/m 2), and obese group (25 patients in group C, BMI>30 kg/m 2). The BMI of groups A, B, and C were (23.35±0.89), (26.65±1.03), and (32.05±1.47) kg/m 2, respectively. There was no significant difference ( P>0.05) in gender, age, surgical side, disease duration, and preoperative Hospital for Special Surgery (HSS) score, visual analogue scale (VAS) score, knee range of motion, and hip-knee-ankle angle (HKA) between groups. The operation time, intraoperative dominant blood loss, and the decrease of hemoglobin on the 3rd day after operation were recorded and compared between groups. The improvement of knee joint function and pain status were evaluated by knee joint HSS score, knee range of motion, and VAS score before and after operation, and measuring the HKA of patients on X-ray film. During the follow-up, the X-ray films of the knee joint were reexamined to observe the position of the internal fixator and the healing of osteotomy. Results: All patients completed the operation successfully and were followed up 8-40 months (mean, 19.3 months). There was no significant difference in follow-up time, operation time, intraoperative dominant blood loss, and the decrease of hemoglobin on the 3rd day after operation between groups ( P>0.05). No operative complications such as severe vascular or nerve injury occurred. After operation, deep venous thrombosis of lower extremities occurred in 1 case in groups A and B respectively, and fat liquefaction of surgical incision occurred in 2 cases in group C. There was no significant difference in the incidence of perioperative complications between groups (3.1% vs. 3.7% vs. 8.0%) ( P=0.689). During the follow-up, there was no bone nonunion, plate fracture or loosening. At last follow-up, HSS score, VAS score, knee range of motion, and HKA significantly improved in the 3 groups when compared with those before operation ( P<0.05), but there was no significant difference in the differences of the above indexes between groups before and after operation ( P>0.05). Conclusion: BMI does not affect the short-term effectiveness of HTO in the treatment of varus knee arthritis. HTO can be selected for overweight and obese patients after standard medical treatment is ineffective.

Network pharmacological analysis to reveal the mechanism governing the effect of Qin Xi Tong on osteoarthritis and rheumatoid arthritis.

INTRODUCTION: Qin Xi Tong (QXT), produced by water extracts of Caulis Sinomenii, is clinically effective in the therapy of rheumatoid arthritis (RA). It is also a complementary agent for osteoarthritis (OA). This study aimed to screen the candidate targets and identify the potential mechanisms of QXT against RA and OA. METHOD: The active ingredients contained in QXT were queried from the TCMSP database. Their predicted targets were obtained through web-based databases, including TCMSP, BATMAN-TCM, CTD, and PharmMapper. The OA and RA targets were collected from the Genecards database and the GSE55235 dataset. Based on the DAVID database, GO and KEGG enrichment analyses of disease-drug common targets predicted potential signaling pathways for QXT. In addition, core targets were identified by mapping component-target-disease interaction networks with Cytoscape 3.9.1 and STRING. The Swissdock and Pymol tools further validate the predicted results. RESULTS: A total of 161 genes were put forward as potential targets for treating RA and OA. These genes might be involved in joint inflammation, including the IL-17 signaling pathway, MAPK signaling pathway, and TNF signaling pathway. They also regulated the progression of joint injuries, such as apoptosis, Th17 cell differentiation, and osteoclast differentiation. In addition, we identified 12 core targets of QXT. Molecular docking results showed that QXT has a high affinity with these core targets. CONCLUSIONS: This study reveals the mechanism governing the effect of QXT on RA and OA, predicts the direct target, and provides new ideas for clinical treatment. Key Points • Our study reveals the underlying mechanism of QXT in the treatment of RA and OA. • Further research into the effects of compounds in QXT alone would be of interest.

A ubiquitination-mediated degradation system to target 14-3-3-binding phosphoproteins.

The phosphorylation of 14-3-3 binding motif is involved in many cellular processes. A strategy that enables targeted degradation of 14-3-3-binding phosphoproteins (14-3-3-BPPs) for studying their functions is highly desirable for basic research. Here, we report a phosphorylation-induced, ubiquitin-proteasome-system-mediated targeted protein degradation (TPD) strategy that allows specific degradation of 14-3-3-BPPs. Specifically, by ligating a modified von Hippel-Lindau E3-ligase with an engineered 14-3-3 bait, we generated a protein chimera referred to as Targeted Degradation of 14-3-3-binding PhosphoProtein (TDPP). TDPP can serve as a universal degrader for 14-3-3-BPPs based on the specific recognition of the phosphorylation in 14-3-3 binding motifs. TDPP shows high efficiency and specificity to a difopein-EGFP reporter, general and specific 14-3-3-BPPs. TDPP can also be applied for the validation of 14-3-3-BPPs. These results strongly support TDPP as a powerful tool for 14-3-3 related research.

Genomic profiling of WRKY transcription factors and functional analysis of CcWRKY7, CcWRKY29, and CcWRKY32 related to protoberberine alkaloids biosynthesis in Coptis chinensis Franch.

Coptis chinensis Franch. (Huanglian in Chinese) is an important economic crop with medicinal value. Its rhizome has been used as a traditional herbal medicine for thousands of years in Asia. Protoberberine alkaloids, as the main bioactive component of Coptis chinensis, have a series of pharmacological activities. However, the protoberberine alkaloids content of C. chinensis is relatively low. Understanding the molecular mechanisms affecting the transcriptional regulation of protoberberine alkaloids would be crucial to increase their production via metabolic engineering. WRKY, one of the largest plant-specific gene families, regulates plant defense responses via the biosynthesis of specialized metabolites such as alkaloids. Totally, 41 WRKY transcription factors (TFs) related to protoberberine alkaloid biosynthesis were identified in the C. chinensis genome and classified into three groups based on phylogenetic and conserved motif analyses. Three WRKY genes (CcWRKY7, CcWRKY29, and CcWRKY32) may regulate protoberberine alkaloid biosynthesis, as suggested by gene-specific expression patterns, metabolic pathways, phylogenetic, and dual-luciferase analysis. Furthermore, the CcWRKY7, CcWRKY29, and CcWRKY32 proteins were specifically detected in the nucleus via subcellular localization. This study provides a basis for understanding the regulatory mechanisms of protoberberine alkaloid biosynthesis and valuable information for breeding C. chinensis varieties.

Decoding CRISPR-Cas PAM recognition with UniDesign.

The critical first step in Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-associated (CRISPR-Cas) protein-mediated gene editing is recognizing a preferred protospacer adjacent motif (PAM) on target DNAs by the protein's PAM-interacting amino acids (PIAAs). Thus, accurate computational modeling of PAM recognition is useful in assisting CRISPR-Cas engineering to relax or tighten PAM requirements for subsequent applications. Here, we describe a universal computational protein design framework (UniDesign) for designing protein-nucleic acid interactions. As a proof of concept, we applied UniDesign to decode the PAM-PIAA interactions for eight Cas9 and two Cas12a proteins. We show that, given native PIAAs, the UniDesign-predicted PAMs are largely identical to the natural PAMs of all Cas proteins. In turn, given natural PAMs, the computationally redesigned PIAA residues largely recapitulated the native PIAAs (74% and 86% in terms of identity and similarity, respectively). These results demonstrate that UniDesign faithfully captures the mutual preference between natural PAMs and native PIAAs, suggesting it is a useful tool for engineering CRISPR-Cas and other nucleic acid-interacting proteins. UniDesign is open-sourced at https://github.com/tommyhuangthu/UniDesign.

Application of machine learning in Chinese medicine differentiation of dampness-heat pattern in patients with type 2 diabetes mellitus.

Background: China has become the country with the largest number of people with type 2 diabetes mellitus (T2DM), and Chinese medicine (CM) has unique advantages in preventing and treating T2DM, while accurate pattern differentiation is the guarantee for proper treatment. Objective: The establishment of the CM pattern differentiation model of T2DM is helpful to the pattern diagnosis of the disease. At present, there are few studies on dampness-heat pattern differentiation models of T2DM. Therefore, we establish a machine learning model, hoping to provide an efficient tool for the pattern diagnosis of CM for T2DM in the future. Methods: A total of 1021 effective samples of T2DM patients from ten CM hospitals or clinics were collected by a questionnaire including patients' demographic and dampness-heat-related symptoms and signs. All information and the diagnosis of the dampness-heat pattern of patients were completed by experienced CM physicians at each visit. We applied six machine learning algorithms (Artificial Neural Network [ANN], K-Nearest Neighbor [KNN], Naïve Bayes [NB], Support Vector Machine [SVM], Extreme Gradient Boosting [XGBoost] and Random Forest [RF]) and compared their performance. And then we also utilized Shapley additive explanation (SHAP) method to explain the best performance model. Results: The XGBoost model had the highest AUC (0.951, 95% CI 0.925-0.978) among the six models, with the best sensitivity, accuracy, F1 score, negative predictive value, and excellent specificity, precision, and positive predictive value. The SHAP method based on XGBoost showed that slimy yellow tongue fur was the most important sign in dampness-heat pattern diagnosis. The slippery pulse or rapid-slippery pulse, sticky stool with ungratifying defecation also performed an important role in this diagnostic model. Furthermore, the red tongue acted as an important tongue sign for the dampness-heat pattern. Conclusion: This study constructed a dampness-heat pattern differentiation model of T2DM based on machine learning. The XGBoost model is a tool with the potential to help CM practitioners make quick diagnosis decisions and contribute to the standardization and international application of CM patterns.

Metaflammation in glucolipid metabolic disorders: Pathogenesis and treatment.

The public health issue of glucolipid metabolic disorders (GLMD) has grown significantly, posing a grave threat to human wellness. Its prevalence is rising yearly and tends to affect younger people. Metaflammation is an important mechanism regulating body metabolism. Through a complicated multi-organ crosstalk network involving numerous signaling pathways such as NLRP3/caspase-1/IL-1, NF-B, p38 MAPK, IL-6/STAT3, and PI3K/AKT, it influences systemic metabolic regulation. Numerous inflammatory mediators are essential for preserving metabolic balance, but more research is needed to determine how they contribute to the co-morbidities of numerous metabolic diseases. Whether controlling the inflammatory response can influence the progression of GLMD determines the therapeutic strategy for such diseases. This review thoroughly examines the role of metaflammation in GLMD and combs the research progress of related therapeutic approaches, including inflammatory factor-targeting drugs, traditional Chinese medicine (TCM), and exercise therapy. Multiple metabolic diseases, including diabetes, non-alcoholic fatty liver disease (NAFLD), cardiovascular disease, and others, respond therapeutically to anti-inflammatory therapy on the whole. Moreover, we emphasize the value and open question of anti-inflammatory-based means for treating GLMD.

Establishing an RNA fusions panel in soft tissue sarcoma with clinical validation.

The diagnosis and classification of soft tissue sarcomas (STS) remain challenging because of the rarity and overlapping morphologic manifestations of diverse STS subtypes. Characteristic gene fusions are commonly detected in STS and represent useful diagnostic markers. This study established and validated a custom-designed RNA sequencing panel that identified 64 gene fusions in STS. The analytical performance validation yielded excellent accuracy, with 100% (95% CI, 94.40%-100%) sensitivity and 93.33% (95% CI, 68.05%-99.83%) specificity. Clinical performances were further confirmed with 145 clinical formalin-fixed and paraffin-embedded (FFPE) samples from STS patients. Fusions were detected in 40% of samples (58/145). The common fusions SS18-SSX family, EWSR1-related fusions, COL1A1-PDGFB, FOXO1-associated fusions, and FUS-associated fusions were identified in corresponding STS subtypes. The RNA panel detected specific fusions in several cases where no conclusive diagnosis can be made based on the morphology and immunohistochemistry results. Data collected in this study demonstrate that the RNA fusions panel can better classify STS subtypes and serve as a good supplement for histopathology, exhibiting a great potential for the STS precise diagnosis.

[Risk factors for osteonecrosis of femoral head after femoral neck fracture fixation with femoral neck system].

Objective: To explore the risk factors for osteonecrosis of the femoral head (ONFH) after treatment of femoral neck fractures with femoral neck system (FNS). Methods: Between January 2020 and February 2021, 179 patients (182 hips) with femoral neck fractures treated by FNS fixation were selected for retrospective analysis. There were 96 males and 83 females with an average age of 53.7 years (range, 20-59 years). There were 106 cases of low-energy-induced injury and 73 cases of high-energy-induced injury. The fractures were classified as type Ⅱ in 40 hips, type Ⅲ in 78 hips, and type Ⅳ in 64 hips according to Garden classification standard, and as typeⅠin 23 hips, type Ⅱ in 66 hips, and type Ⅲ in 93 hips according to Pauwels classification standard. There were 21 patients with diabetes. Patients were divided into ONFH group and non-ONFH group according to whether ONFH occurred at last follow-up. The data of the patients were collected, including age, gender, body mass index (BMI), trauma mechanism, bone mineral density, having diabetes or not, Garden classification and Pauwels classification of fractures, fracture reduction quality, femoral head retroversion angle, and removal of internal fixator or not. The above factors were analyzed by univariate analysis, and then multivariate logistic regression analysis was used to identify risk factors. Results: Total 179 patients (182 hips) were followed up 20-34 months (mean, 26.5 months). Of these, 30 cases (30 hips) developed ONFH at 9-30 months after operation (ONFH group), and the incidence of ONFH was 16.48%. And 149 cases (152 hips) had no ONFH at last follow-up (non-ONFH group). The univariate analysis showed that there were significant differences between groups in bone mineral density, having diabetes or not, Garden classification, femoral head retroversion angle, and fracture reduction quality ( P<0.05). The multivariate logistic regression analysis showed that the Garden type Ⅳ fracture, reduction quality of grading Ⅲ, femoral head retroversion angle >15°, complicated with diabetes were the risk factors for ONFH after FNS fixation ( P<0.05). Conclusion: For the patients with Garden type Ⅳ fracture, poor quality of fracture reduction, femoral head retroversion angle >15°, and diabetes, the risk of ONFH after FNS fixation increases.

De novo protein fold design through sequence-independent fragment assembly simulations.

De novo protein design generally consists of two steps, including structure and sequence design. Many protein design studies have focused on sequence design with scaffolds adapted from native structures in the PDB, which renders novel areas of protein structure and function space unexplored. We developed FoldDesign to create novel protein folds from specific secondary structure (SS) assignments through sequence-independent replica-exchange Monte Carlo (REMC) simulations. The method was tested on 354 non-redundant topologies, where FoldDesign consistently created stable structural folds, while recapitulating on average 87.7% of the SS elements. Meanwhile, the FoldDesign scaffolds had well-formed structures with buried residues and solvent-exposed areas closely matching their native counterparts. Despite the high fidelity to the input SS restraints and local structural characteristics of native proteins, a large portion of the designed scaffolds possessed global folds completely different from natural proteins in the PDB, highlighting the ability of FoldDesign to explore novel areas of protein fold space. Detailed data analyses revealed that the major contributions to the successful structure design lay in the optimal energy force field, which contains a balanced set of SS packing terms, and REMC simulations, which were coupled with multiple auxiliary movements to efficiently search the conformational space. Additionally, the ability to recognize and assemble uncommon super-SS geometries, rather than the unique arrangement of common SS motifs, was the key to generating novel folds. These results demonstrate a strong potential to explore both structural and functional spaces through computational design simulations that natural proteins have not reached through evolution.

[Research progress of femoral neck system in treatment of femoral neck fracture in young and middle-aged patients].

Objective: To summarize the research progress of femoral neck system (FNS) in the treatment of femoral neck fracture in young and middle-aged patients. Methods: The literature on FNS at home and abroad in recent years was extensively reviewed, and the results of mechanical and clinical studies on FNS were summarized based on clinical experience. Results: FNS has good mechanical stability, which can reduce complications such as femoral neck shortening, internal fixation failure, and varus caused by mechanical instability. At present, FNS is mainly selected for comparison with cannulated compression screws and dynamic hip screws in clinical research. The results show that FNS has the advantages of minimally invasive, short operation time, less intraoperative fluoroscopy, earlier postoperative weight-bearing and fracture healing, and better hip function recovery. Conclusion: As a new internal fixator, FNS has achieved satisfactory results in the current research. FNS has good mechanical advantages, which is beneficial to fracture healing and the recovery of hip joint function after operation. However, whether FNS can reduce the incidence of nonunion and osteonecrosis of the femoral head remains to be further clarified.

Current Status and Factors Associated with Clean Operating Rooms: A Survey of Hospitals in China.

Background: Indoor air quality is controlled in the clean operating room (OR) to reduce the risk of surgical-site infections (SSIs). The aim of this study is to assess the usage and management of clean ORs in China and to identify factors associated with the risk of SSIs. Methods: An online survey was distributed to hospitals in China from August 5 to September 5, 2018 via the WeChat account of the Shanghai International Forum for Infection Control and Prevention. The questionnaire consisted of two parts: basic information (hospital type, level, and number of beds) and usage and management (number of ORs, usage time, maintenance mode, test frequency, compliance with current standards, and comfort of healthcare workers). The significance of factors associated with the cleanliness and maintenance of clean ORs was assessed by univariate and multivariate logistic regression analyses. Results: Among 1,308 responding hospitals, 25.7% failed to comply with current standards. "Maintenance mode" had a significant effect on compliance with current standards for clean ORs (p < 0.0001) and "professional" maintenance was superior to "outsource or no" maintenance (odds ratio = 0.511, 95% confidence interval = 0.367-0.711). There was a significant difference in the comfort of healthcare workers in clean ORs that complied with current standards vs. those that did not (39.92% [388/972] vs. 64.28% [216/336], respectively, p < 0.0001). Humidity was the chief complaint among healthcare workers. Conclusion: Maintenance of clean ORs was significantly associated with the compliance of current standards. Noncompliance with current standards was associated with greater risks of SSIs. Maintenance of ORs for prevention of SSIs should consider the costs and benefits.

Recent Advances in Improving Gene-Editing Specificity through CRISPR-Cas9 Nuclease Engineering.

CRISPR-Cas9 is the state-of-the-art programmable genome-editing tool widely used in many areas. For safe therapeutic applications in clinical medicine, its off-target effect must be dramatically minimized. In recent years, extensive studies have been conducted to improve the gene-editing specificity of the most popular CRISPR-Cas9 nucleases using different strategies. In this review, we summarize and discuss these strategies and achievements, with a major focus on improving the gene-editing specificity through Cas9 protein engineering.