Pyran- and furanocoumarins are key representatives of tetrahydropyrans and tetrahydrofurans, respectively, exhibiting diverse physiological and medical bioactivities. However, the biosynthetic mechanisms for their core structures remain poorly understood. Here we combined multiomics analyses of biosynthetic enzymes in Peucedanum praeruptorum and in vitro functional verification and identified two types of key enzymes critical for pyran and furan ring biosynthesis in plants. These included three distinct P. praeruptorum prenyltransferases (PpPT1-3) responsible for the prenylation of the simple coumarin skeleton 7 into linear or angular precursors, and two novel CYP450 cyclases (PpDC and PpOC) crucial for the cyclization of the linear/angular precursors into either tetrahydropyran or tetrahydrofuran scaffolds. Biochemical analyses of cyclases indicated that acid/base-assisted epoxide ring opening contributed to the enzyme-catalyzed tetrahydropyran and tetrahydrofuran ring refactoring. The possible acid/base-assisted catalytic mechanisms of the identified cyclases were theoretically investigated and assessed using site-specific mutagenesis. We identified two possible acidic amino acids Glu303 in PpDC and Asp301 in PpOC as vital in the catalytic process. This study provides new enzymatic tools in the epoxide formation/epoxide-opening mediated cascade reaction and exemplifies how plants become chemically diverse in terms of enzyme function and catalytic process.

Objective To summarize the epidemiological and clinical features of infectious diseases of the central nervous system(CNS)by a single-center analysis.Methods A retrospective analysis was conducted on the data of 1247 cases of CNS infectious diseases diagnosed and treated in the First Medical Center of PLA General Hospital from 2001 to 2020.Results The data for this group of CNS infectious diseases by disease type in descending order of number of cases were viruses 743(59.6％),Mycobacterium tuberculosis 249(20.0％),other bacteria 150(12.0％),fungi 68(5.5％),parasites 18(1.4％),Treponema pallidum 18(1.4％)and rickettsia 1(0.1％).The number of cases increased by 177 cases(33.1％)in the latter 10 years compared to the previous 10 years(P<0.05).No significant difference in seasonal distribution pattern of data between disease types(P>0.05).Male to female ratio is 1.87︰1,mostly under 60 years of age.Viruses are more likely to infect students,most often at university/college level and above,farmers are overrepresented among bacteria and Mycobacterium tuberculosis,and more infections of Treponema pallidum in workers.CNS infectious diseases are characterized by fever,headache and signs of meningeal irritation,with the adductor nerve being the more commonly involved cranial nerve.Matagenomic next-generation sequencing improves clinical diagnostic capabilities.The median hospital days for CNS infectious diseases are 18.00(11.00,27.00)and median hospital costs are ￥29,500(￥16,000,￥59,200).The mortality rate from CNS infectious diseases is 1.6％.Conclusions The incidence of CNS infectious diseases is increasing last ten years,with complex clinical presentation,severe symptoms and poor prognosis.Early and accurate diagnosis and standardized clinical treatment can significantly reduce the morbidity and mortality rate and ease the burden of disease.

Nanozyme is novel nanoparticle with enzyme-like activity, which can be classified into peroxidase-like nanozyme, catalase-like nanozyme, superoxide dismutase-like nanozyme, oxidase-like nanozyme and hydrolase-like nanozyme according to the type of reaction they catalyze. Since researchers first discovered Fe₃O₄ nanoparticles with peroxidase-like activity in 2007, a variety of nanoparticles have been successively found to have catalytic activity and applied in bioassays, inflammation control, antioxidant damage and tumor therapy, playing a key role in disease diagnosis and treatment. We summarize the use of nanozymes with different classes of enzymatic activity in the diagnosis and treatment of diseases and describe the main factors influencing nanozyme activity. A Mn-based peroxidase-like nanozyme that induces the reduction of glutathione in tumors to produce glutathione disulfide and Mn²⁺, which induces the production of reative oxygen species (ROS) in tumor cells by breaking down H₂O₂ in physiological media through Fenton-like action, thereby inhibiting tumor cell growth. To address the limitation of tumor tissue hypoxia during photodynamic tumor therapy, the effect of photodynamic therapy is significantly enhanced by using hydrogen peroxide nanozymes to catalyze the production of oxygen from H₂O₂. In pathological states, where excess superoxide radicals are produced in the body, superoxide dismutase-like nanozymes are able to selectively regulate intracellular ROS levels, thereby protecting normal cells and slowing down the degradation of cellular function. Based on this principle, an engineered nanosponge has been designed to rapidly scavenge free radicals and deliver oxygen in time to save nerve cells before thrombolysis. Starvation therapy, in which glucose oxidase catalyzes the hydrolysis of glucose to gluconic acid and hydrogen peroxide in cancer cells with the involvement of oxygen, attenuates glycolysis and the production of intermediate metabolites such as nucleotides, lipids and amino acids, was used to synthesize an oxidase-like nanozyme that achieved effective inhibition of tumor growth. Furthermore, by fine-tuning the Lewis acidity of the metal cluster to improve the intrinsic activity of the hydrolase nanozyme and providing a shortened ligand length to increase the density of its active site, a hydrolase-like nanozyme was successfully synthesized that is capable of cleaving phosphate bonds, amide bonds, glycosidic bonds and even biofilms with high efficiency in hydrolyzing the substrate. All these effects depend on the size, morphology, composition, surface modification and environmental media of the nanozyme, which are important aspects to consider in order to improve the catalytic efficiency of the nanozyme and have important implications for the development of nanozyme. Although some progress has been made in the research of nanozymes in disease treatment and diagnosis, there are still some problems, for example, the catalytic rate of nanozymes is still difficult to reach the level of natural enzymes in vivo, and the toxic effects of some heavy metal nanozymes material itself. Therefore, the construction of nanozyme systems with multiple functions, good biocompatibility and high targeting efficiency, and their large-scale application in diagnosis and treatment is still an urgent problem to be solved. (1) To improve the selectivity and specificity of nanozymes. By using antibody coupling, the nanoparticles are able to specifically bind to antigens that are overexpressed in certain cancer cells. It also significantly improves cellular internalization through antigen-mediated endocytosis and enhances the enrichment of nanozymes in target tissues, thereby improving targeting during tumor therapy. Some exogenous stimuli such as laser and ultrasound are used as triggers to control the activation of nanozymes and achieve specific activation of nanozyme. (2) To explore more practical and safer nanozymes and their catalytic mechanisms: biocompatible, clinically proven material molecules can be used for the synthesis of nanoparticles. (3) To solve the problem of its standardization and promote the large-scale clinical application of nanozymes in biomonitoring. Thus, it can go out of the laboratory and face the market to serve human health in more fields, which is one of the future trends of nanozyme development.

Objective To compare the efficacy and safety of different courses of caffeine citrate injection in the treatment of very low birth weight infants.Methods Very low birth weight infants were divided into long course group and routine course according to cohort method.2 groups of children were given intravenous infusion of caffeine citrate injection loading dose(20 mg·kg-1)within 3 days after birth,and the dose was maintained at 5 mg·kg-1 after 24 hours(qd).In the long course group,caffeine citrate injection was used to correct gestational age＞34 weeks,and in the routine course,caffeine citrate injection was used to correct gestational age 33-34 weeks.The use of caffeine citrate injection,clinical efficacy,neonatal behavioral neurological scale(NBNA)score and the occurrence of adverse drug reactions were compared between the two groups.Results 116 cases were included in this study,64 cases in the long course group and 52 cases in the routine course.After treatment,the total clinical effective rate of the long course group and the routine course was 92.19％and 94.23％,respectively,with no statistical significance(P＞0.05).The total duration of caffeine citrate injection were(60.53±8.92)and(48.17±5.24)days,respectively;the corrected gestational age at withdrawal were(36.02±1.56)and(33.18±1.27)weeks,respectively.The corrected gestational age were(34.31±0.48)and(32.06±0.51)weeks;the milk volume were(32.69±2.14)and(23.85±1.69)mL,respectively,with statistical significance(all P＜0.05).The starting age of caffeine citrate injection were(59.65±3.42)and(58.35±3.11)h in the long course group and the routine course,respectively,with no statistical significance(P＞0.05).Before treatment,the NBNA score of the long course and routine courses were 36.49±6.78 and 35.58±4.22,respectively;the NBNA score of long course and conventional course after treatment were 43.25±6.88 and 44.12±7.42,respectively.Compared with before treatment,NBNA score in both groups were higher after treatment,with statistical significance(all P＜0.05).There was no significant difference in NBNA score between the long course group and the routine course(P＞0.05).The incidence of bronchopulmonary dysplasia(84.38％vs 51.92％)and decreased hemoglobin concentration(17.75％vs 5.77％)in the long course group were significantly higher than those in the routine course(all P＜0.05).Conclusion Long-term use of caffeine citrate injection to correct gestational age＞34 weeks has no significant effect on clinical treatment,neurological function and intellectual development of very low birth weight infants.

Objective This study employs the Geographically and Temporally Weighted Regression(GTWR)model to assess the impact of meteorological elements and imported cases on dengue fever outbreaks,emphasizing the spatial-temporal variability of these factors in border regions. Methods We conducted a descriptive analysis of dengue fever's temporal-spatial distribution in Yunnan border areas.Utilizing annual data from 2013 to 2019,with each county in the Yunnan border serving as a spatial unit,we constructed a GTWR model to investigate the determinants of dengue fever and their spatio-temporal heterogeneity in this region. Results The GTWR model,proving more effective than Ordinary Least Squares(OLS)analysis,identified significant spatial and temporal heterogeneity in factors influencing dengue fever's spread along the Yunnan border.Notably,the GTWR model revealed a substantial variation in the relationship between indigenous dengue fever incidence,meteorological variables,and imported cases across different counties. Conclusion In the Yunnan border areas,local dengue incidence is affected by temperature,humidity,precipitation,wind speed,and imported cases,with these factors'influence exhibiting notable spatial and temporal variation.

AIM To explore the effects of Buyang Huanwu Decoction on mitochondrial oxidative damage and PKCε-Nampt pathway in rats following cerebral ischemia reperfusion(I/R).METHODS The rats were randomly divided into the sham operation group,the model group,Buyang Huanwu Decoction group(14.3 g/kg)and edaravone group(3 mg/kg).Except those of the sham operation group,SD rats of other groups were induced into models of brain I/R injury by MCAO method,followed by corresponding drug administration 24 hours after operation.After 7 days of administration,the rats had their neurological deficit evaluated by neurological function scoring;thier expression of neuron marker MAP-2 detected by immunofluorescence staining;their neuron damage observed and the oxidative damage evaluated through assessment of their ROS levels and MDA and SOD activities;their changes of mitochondrial membrane potential detected by fluorescent probe JC-1;their ratio of NAD+/NADH detected using modified enzyme circulation method;their expressions of PKCε,p-PKCε and Nampt proteins detected with Western blot;and their positive expressions of p-PKCε and Nampt proteins detected with immunohistochemistry method.RESULTS Compared with the model group,Buyang Huanwu Decoction group shared decreased cerebral infarction volume and neurological function score(P<0.05);increased cerebral fluorescence intensity of MAP-2(P<0.05);reduced neuronal damage,decreased cerebral levels of ROS and MDA(P<0.05);increased SOD activity,mitochondrial membrane potential and NAD+/NADH ratio(P<0.05);and increased protein expressions of p-PKCε and Nampt(P<0.05).CONCLUSION Buyang Huanwu Decoction can improve mitochondrial function and reduce brain I/R injury in rats by activating their PKCε-Nampt signaling pathway.

Objective The aim of this study is to explore the potential modulatory role of quercetin against Endotoxin or lipopolysaccharide (LPS) induced septic cardiac dysfunction.Methods Specific pathogen-free chicken embryos (n = 120) were allocated untreated control, phosphate buffer solution (PBS) vehicle, PBS with ethanol vehicle, LPS (500 ng/egg), LPS with quercetin treatment (10, 20, or 40 nmol/egg, respectively), Quercetin groups (10, 20, or 40 nmol/egg). Fifteen-day-old embryonated eggs were inoculated with abovementioned solutions via the allantoic cavity. At embryonic day 19, the hearts of the embryos were collected for histopathological examination, RNA extraction, real-time polymerase chain reaction, immunohistochemical investigations, and Western blotting.Results They demonstrated that the heart presented inflammatory responses after LPS induction. The LPS-induced higher mRNA expressions of inflammation-related factors (TLR4, TNFα, MYD88, NF-κB1, IFNγ, IL-1β, IL-8, IL-6, IL-10, p38, MMP3, and MMP9) were blocked by quercetin with three dosages. Quercetin significantly decreased immunopositivity to TLR4 and MMP9 in the treatment group when compared with the LPS group. Quercetin significantly decreased protein expressions of TLR4, IFNγ, MMP3, and MMP9 when compared with the LPS group. Quercetin treatment prevented LPS-induced increase in the mRNA expression of Claudin 1 and ZO-1, and significantly decreased protein expression of claudin 1 when compared with the LPS group. Quercetin significantly downregulated autophagy-related gene expressions (PPARα, SGLT1, APOA4, AMPKα1, AMPKα2, ATG5, ATG7, Beclin-1, and LC3B) and programmed cell death (Fas, Bcl-2, CASP1, CASP12, CASP3, and RIPK1) after LPS induction. Quercetin significantly decreased immunopositivity to APOA4, AMPKα2, and LC3-II/LC3-I in the treatment group when compared with the LPS group. Quercetin significantly decreased protein expressions of AMPKα1, LC3-I, and LC3-II. Quercetin significantly decreased the protein expression to CASP1 and CASP3 by immunohistochemical investigation or Western blotting in treatment group when compared with LPS group.Conclusion Quercetin alleviates cardiac inflammation induced by LPS through modulating autophagy, programmed cell death, and myocardiocytes permeability.

Objective:To explore the effects of the scaffolding-based flipped classroom approach in the teaching of Infectious Disease Nursing. Methods:We assigned 152 students of nursing and midwifery majors of grade 2018 (experimental group) to be taught using the scaffolding-based flipped classroom approach and 182 students of grade 2017 (control group) to be taught using the traditional lecture method. Teaching effects were evaluated through students' exam performance and a questionnaire survey. Numerical data were analyzed using the χ2 test and t test with the use of SPSS 18.0, and text data were processed using NVivo 11 for thematic analysis. Results:The experimental group and control group showed significant differences in the interim exam score (83.19±7.96 vs. 79.62±3.14, P<0.001) and final exam score (78.47±6.92 vs. 73.16±8.24, P<0.001). The students of grade 2018 had a high level of participation in online learning. The questionnaire results showed that the scaffolding-based flipped classroom was well recognized in terms of students' overall perception, perceived course quality, perceived value of learning, and satisfaction and the open-ended question, with low scores for learner complaints and loyalty. Conclusions:The scaffolding-based flipped classroom is feasible in the teaching of Infectious Disease Nursing, which can improve students' academic performance and overall competence.

A high-throughput three-dimensional (3D) hepatocyte culture model is constructed in this study. It is capable of replicating the 3D in vivo environment and offers the advantages of high throughput, enhanced reproducibility, low cost, and simplified operation, rendering a valuable tool for hepatotoxicity screening of traditional Chinese medicine (TCM). First, we constructed the 3D high throughput liver chip model using collagen hydrogel. The precision and its difference with traditional cell culture plates were assessed using acetaminophen, Tripterygium hypoglaucum, and Qili San as the references. The feasibility of this model was also investigated by comparing the hepatotoxicity among four batches of T. hypoglaucum and Qili San. The methodology verification shows that the 3D hepatocyte model is better than traditional two-dimensional (2D) cell culture model in precision and feasibility. Subsequently, we compared the hepatotoxicity of different samples over a period of three or seven days and found that the hepatotoxicity of TCM extracts increased over time. Finally, we compared the hepatotoxicity of T. hypoglaucum and its compound formula Kunxian capsule under equivalent concentration. The results showed that the compound Kunxian capsule could significantly reduce hepatotoxicity of T. hypoglaucum. Generally, we constructed a high-throughput, robust 3D liver-on-a-chip model with the potential of rapid assessing TCM-induced liver toxicity.

Drug loading is an important index to evaluate the quality of solid preparation of traditional Chinese medicine. Drug loading is restricted by drug characteristics, dosage form, process, and drug delivery in vivo, which affects the preparation process, therapeutic effect, and drug release rate. By consulting domestic and foreign literature, this paper put forward the significance of increasing the drug loading: improving the compliance of patients, reducing the production cost, reducing the risk of the excipients. In this review, the possible approaches to increase drug loading, such as the selection of high-efficiency excipients, suitable drug preparation techniques, and modification of the physical properties of drugs are summarized. It will provide theoretical basis through this review for the development of high drug loading and high-quality formulations.