Collagen is a major structural protein in the matrix of animal cells and the most widely distributed and abundant functional protein in mammals. Collagen’s good biocompatibility, biodegradability and biological activity make it a very valuable biomaterial. According to the source of collagen, it can be broadly categorized into two types: one is animal collagen; the other is recombinant collagen. Animal collagen is mainly extracted and purified from animal connective tissues by chemical methods, such as acid, alkali and enzyme methods, etc. Recombinant collagen refers to collagen produced by gene splicing technology, where the amino acid sequence is first designed and improved according to one’s own needs, and the gene sequence of improved recombinant collagen is highly consistent with that of human beings, and then the designed gene sequence is cloned into the appropriate vector, and then transferred to the appropriate expression vector. The designed gene sequence is cloned into a suitable vector, and then transferred to a suitable expression system for full expression, and finally the target protein is obtained by extraction and purification technology. Recombinant collagen has excellent histocompatibility and water solubility, can be directly absorbed by the human body and participate in the construction of collagen, remodeling of the extracellular matrix, cell growth, wound healing and site filling, etc., which has demonstrated significant effects, and has become the focus of the development of modern biomedical materials. This paper firstly elaborates the structure, type, and tissue distribution of human collagen, as well as the associated genetic diseases of different types of collagen, then introduces the specific process of producing animal source collagen and recombinant collagen, explains the advantages of recombinant collagen production method, and then introduces the various systems of expressing recombinant collagen, as well as their advantages and disadvantages, and finally briefly introduces the application of animal collagen, focusing on the use of animal collagen in the development of biopharmaceutical materials. In terms of application, it focuses on the use of animal disease models exploring the application effects of recombinant collagen in wound hemostasis, wound repair, corneal therapy, female pelvic floor dysfunction (FPFD), vaginal atrophy (VA) and vaginal dryness, thin endometritis (TE), chronic endometritis (CE), bone tissue regeneration in vivo, cardiovascular diseases, breast cancer (BC) and anti-aging. The mechanism of action of recombinant collagen in the treatment of FPFD and CE was introduced, and the clinical application and curative effect of recombinant collagen in skin burn, skin wound, dermatitis, acne and menopausal urogenital syndrome (GSM) were summarized. From the exploratory studies and clinical applications, it is evident that recombinant collagen has demonstrated surprising effects in the treatment of all types of diseases, such as reducing inflammation, promoting cell proliferation, migration and adhesion, increasing collagen deposition, and remodeling the extracellular matrix. At the end of the review, the challenges faced by recombinant collagen are summarized: to develop new recombinant collagen types and dosage forms, to explore the mechanism of action of recombinant collagen, and to provide an outlook for the future development and application of recombinant collagen.

ObjectiveJunctophilin-2 (JPH2) is an essential structural protein that maintains junctional membrane complexes (JMCs) in cardiomyocytes by tethering the plasma membrane to the sarcoplasmic reticulum, thereby facilitating excitation-contraction (E-C) coupling. Mutations in JPH2 have been associated with hypertrophic cardiomyopathy (HCM), but the molecular mechanisms governing its membrane-binding properties and the functional relevance of its membrane occupation and recognition nexus (MORN) repeat motifs remain incompletely understood. This study aimed to elucidate the structural basis of JPH2 membrane association and its implications for HCM pathogenesis. MethodsA recombinant N-terminal fragment of mouse JPH2 (residues1-440), encompassing the MORN repeats and an adjacent helical region, was purified under near-physiological buffer conditions.X-ray crystallography was employed to determine the structure of the JPH2 MORN-Helix domain. Sequence conservation analysis across species and junctophilin isoforms was performed to assess the evolutionary conservation of key structural features. Functional membrane-binding assays were conducted using liposome co-sedimentation and cell-based localization studies in COS7 and HeLa cells. In addition, site-directed mutagenesis targeting positively charged residues and known HCM-associated mutations, including R347C, was used to evaluate their effects on membrane interaction and subcellular localization. ResultsThe crystal structure of the mouse JPH2 MORN-Helix domain was resolved at 2.6 Å, revealing a compact, elongated architecture consisting of multiple tandem MORN motifs arranged in a curved configuration, forming a continuous hydrophobic core stabilized by alternating aromatic residues. A C-terminal α-helix further reinforced structural integrity. Conservation analysis identified the inner groove of the MORN array as a highly conserved surface, suggesting its role as a protein-binding interface. A flexible linker segment enriched in positively charged residues, located adjacent to the MORN motifs, was found to mediate direct electrostatic interactions with negatively charged phospholipid membranes. Functional assays demonstrated that mutation of these basic residues impaired membrane association, while the HCM-linked R347C mutation completely abolished membrane localization in cellular assays, despite preserving the overall MORN-Helix fold in structural modeling. ConclusionThis study provides structural insight into the membrane-binding mechanism of the cardiomyocyte-specific protein JPH2, highlighting the dual roles of its MORN-Helix domain in membrane anchoring and protein interactions. The findings clarify the structural basis for membrane targeting via a positively charged linker and demonstrate that disruption of this interaction—such as that caused by the R347C mutation—likely contributes to HCM pathogenesis. These results not only enhance current understanding of JPH2 function in cardiac E-C coupling but also offer a structural framework for future investigations into the assembly and regulation of JMCs in both physiological and disease contexts.

Objective To investigate the efficacy and safety of a new type of self-made bone drill applied to percutaneous transforaminal endoscopic discectomy for L5/S1 intervertebral disc herniation.Methods The clinical data of 52 patients with L5/S1 intervertebral disc herniation admitted to our hospital were retrospectively analyzed.All patients underwent percutaneous transforaminal endoscopic discectomy,with a new type of self-made bone drill for foraminoplasty during the surgery.The surgical conditions and occurrence of complications were recorded.The pain of patients before surgery,3 days after surgery,3 months after surgery,6 months after surgery,and 1 year after surgery was assessed by visual analogue scale(VAS);and the neurological function improvement before and after surgery was evaluated by Oswestry disability index(ODI).Results All patients underwent successful surgery without serious complications or recurrence after surgery.The VAS and ODI scores of patients 3 days,3 months,6 months,and 1 year after surgery were significantly lower than those before surgery(P<0.05).Conclusion The self-made new bone drill can significantly improve the efficiency of foraminoplasty and ensure surgical safety,with satisfactory early clinical effect.

The purpose of this study was to identify the tick species native to Xindi Township,Yumin County,Xinjiang,China.Preliminary morphological identification of parasitic ticks collected from animals in the area was conducted with an ultra-depth of field three-dimensional VHX 600 digital stereo microscope.Total DNA of the ticks was extracted,amplified by PCR based on the COI and ITS2 gene loci,and the posi-tive PCR products were sequenced.The sequence were a-ligned with reference sequences from the NCBI database were aligned with the Basic Local Alignment Search Tool.A genet-ic phylogenetic tree was generated with the neighbor-joining method of MEGA 7.0 software to determine the evolutionary biological characteristics of ticks.Morphological identification showed that the ticks collected from Xindi Township of Yu-min County were consistent with the characteristics of Hya-lomma asiaticum.An evolutionary tree based on the COI and ITS2 gene sequences showed that the ticks collected in this study were clustered with known H.asiaticum sequences.The PCR products of COI and ITS2 were sequenced and compared,which confirmed that the collected tick species were H.asiaticum,in agreement with the morphological and molecular biological results.These findings help to clarify the distribution of ticks in Xindi Township of Xinjiang,and provide basic data for the analysis of tick genetic and evolutionary characteristics,as reference for surveillance and control of ticks in the Xinjiang Uygur Autonomous Region.

Pancreatic polypeptide(PP),a pancreatic hormone containing 36 amino acids,plays impor-tant roles in the diagnosis and evaluation of pancreatic function,injury and diseases.In this study,a phage nanobody library against PP was constructed to screen specific PP nanobodies,which would be used to evaluate whether they have binding activity with PP antigen.After PP antigen with high purity was prepared by prokaryotic expression system,it was used to immunize alpaca to construct the nanobody li-brary against PP with high storage capacity and high abundance,from which 8 strains of PP nanobodies were obtained by phage display.One of nanobody strain(PP-VHH)was selected to be expressed in a prokaryotic expression system,which was induced overnight by IPTG.After purification and identifica-tion,the antigen-antibody binding activity and PP level in serum were detected by indirect ELISA and Sandwich ELISA methods,respectively.The results showed that PP-VHH had binding activity with PP,which could be used to detect PP in chicken and human serum.The Sandwich ELISA methods with R2 of the fitting curve 0.9868 could be used to detect PP concentrations of 48-55 pg/mL in the serum of chick-ens,while the concentrations of PP in human serum varied significantly.In summary,PP-VHH screened from nanobody library against PP could detect PP in serum,which would supply the basis for evaluation of abnormal pancreatic function and diagnosis of relative disease.

Objective:To evaluate the efficacy of acute T-cell lymphoblastic leukemia(T-ALL)in children and explore the prognostic risk factors.Methods:The clinical data of 127 newly diagnosed children with T-ALL admitted to five hospitals in Fujian province from April 2011 to December 2020 were retrospectively analyzed,and compared with children with newly diagnosed acute precursor B-cell lymphoblastic leukemia(B-ALL)in the same period.Kaplan-Meier analysis was used to evaluate the overall survival(OS)and event-free survival(EFS),and COX proportional hazard regression model was used to evaluate the prognostic factors.Among 116 children with T-ALL who received standard treatment,78 cases received the Chinese Childhood Leukemia Collaborative Group(CCLG)-ALL 2008 protocol(CCLG-ALL 2008 group),and 38 cases received the China Childhood Cancer Collaborative Group(CCCG)-ALL 2015 protocol(CCCG-ALL 2015 group).The efficacy and serious adverse event(SAE)incidence of the two groups were compared.Results:Proportion of male,age ≥ 10 years old,white blood cell count(WBC)≥ 50 × 109/L,central nervous system leukemia,minimal residual disease(MRD)≥ 1％during induction therapy,and MRD ≥ 0.01％at the end of induction in T-ALL children were significantly higher than those in B-ALL children(P＜0.05).The expected 10-year EFS and OS of T-ALL were 59.7％and 66.0％,respectively,which were significantly lower than those of B-ALL(P＜0.001).COX analysis showed that WBC ≥ 100 x 109/L at initial diagnosis and failure to achieve complete remission(CR)after induction were independent risk factors for poor prognosis.Compared with CCLG-ALL 2008 group,CCCG-ALL 2015 group had lower incidence of infection-related SAE(15.8％vs 34.6％,P=0.042),but higher EFS and OS(73.9％vs 57.2％,PEFS=0.090;86.5％vs 62.3％,PoS=0.023).Conclusions:The prognosis of children with T-ALL is worse than children with B-ALL.WBC ≥ 100 × 109/L at initial diagnosis and non-CR after induction(especially mediastinal mass has not disappeared)are the risk factors for poor prognosis.CCCG-ALL 2015 regimen may reduce infection-related SAE and improve efficacy.

Objective:To investigate the safety and clinical effect of testis-sparing microsurgery(TSMS)in the treatment of benign testis tumor(BTT).Methods:We retrospectively analyzed the clinical data on 16 cases of BTT treated in the Department of Andrology of the Affiliated Hospital of Qingdao University from October 2020 to February 2023.The median age of the patients was 23 years.All the tumors were unilateral,7 in the left and 9 in the right side,with a median diameter of 1.85 cm(1.0-3.5 cm).The patients all underwent color Doppler flow imaging(CDFI),MRI,semen analysis and examination of serum T,alpha-fetoprotein(AFP),human chorionic gonadotropin(HCG)and lactate dehydrogenase(LDH),followed by TSMS.The boundaries between the tumors and normal testis tissue were accurately identified under the microscope,and the tumors and the adjacent normal testis tissue 2 mm from their margins were excised completely.Bipolar coagulation forceps were used for wound hemostasis to maximally preserve the normal testis tissue.The resected specimens were subjected to fast frozen pathology intraoperatively,and the patients were followed up for 14-40 months by regular scrotal CDFI,MRI and examinations of serum T and semen parameters.Results:The levels of serum T,AFP,HCG and LDH and semen parameters were all within the normal range preoperatively.TSMS were successfully completed in all the cases,and all were pathologically confirmed as BTT according to the latest edition of WHO Classification of Tumors:Urinary and Male Genital Tumors.CDFI showed normal blood supply within the testis tissue at 1 month after surgery.No signs of intra-testicu-lar tumor residue,recurrence or metastasis,nor significant changes in the levels of serum T,AFP,HCG or LDH or semen parameters were observed during the follow-up as compared with the baseline.Natural conception was achieved in 2 cases at 16 and 18 months re-spectively after surgery.Conclusion:BTT can be differentially diagnosed by CDFI and MRI before surgery and confirmed by histo-pathology.TSMS can achieve complete excision of the tumor,maximal sparing of the normal testis tissue and thereby effective preserva-tion of male fertility.

Objective To investigate the clinical characteristics and prognosis of pneumococcal meningitis(PM),and drug sensitivity of Streptococcus pneumoniae(SP)isolates in Chinese children.Methods A retrospective analysis was conducted on clinical information,laboratory data,and microbiological data of 160 hospitalized children under 15 years old with PM from January 2019 to December 2020 in 33 tertiary hospitals across the country.Results Among the 160 children with PM,there were 103 males and 57 females.The age ranged from 15 days to 15 years,with 109 cases(68.1% )aged 3 months to under 3 years.SP strains were isolated from 95 cases(59.4% )in cerebrospinal fluid cultures and from 57 cases(35.6% )in blood cultures.The positive rates of SP detection by cerebrospinal fluid metagenomic next-generation sequencing and cerebrospinal fluid SP antigen testing were 40% (35/87)and 27% (21/78),respectively.Fifty-five cases(34.4% )had one or more risk factors for purulent meningitis,113 cases(70.6% )had one or more extra-cranial infectious foci,and 18 cases(11.3% )had underlying diseases.The most common clinical symptoms were fever(147 cases,91.9% ),followed by lethargy(98 cases,61.3% )and vomiting(61 cases,38.1% ).Sixty-nine cases(43.1% )experienced intracranial complications during hospitalization,with subdural effusion and/or empyema being the most common complication[43 cases(26.9% )],followed by hydrocephalus in 24 cases(15.0% ),brain abscess in 23 cases(14.4% ),and cerebral hemorrhage in 8 cases(5.0% ).Subdural effusion and/or empyema and hydrocephalus mainly occurred in children under 1 year old,with rates of 91% (39/43)and 83% (20/24),respectively.SP strains exhibited complete sensitivity to vancomycin(100% ,75/75),linezolid(100% ,56/56),and meropenem(100% ,6/6).High sensitivity rates were also observed for levofloxacin(81% ,22/27),moxifloxacin(82% ,14/17),rifampicin(96% ,25/26),and chloramphenicol(91% ,21/23).However,low sensitivity rates were found for penicillin(16% ,11/68)and clindamycin(6% ,1/17),and SP strains were completely resistant to erythromycin(100% ,31/31).The rates of discharge with cure and improvement were 22.5% (36/160)and 66.2% (106/160),respectively,while 18 cases(11.3% )had adverse outcomes.Conclusions Pediatric PM is more common in children aged 3 months to under 3 years.Intracranial complications are more frequently observed in children under 1 year old.Fever is the most common clinical manifestation of PM,and subdural effusion/emphysema and hydrocephalus are the most frequent complications.Non-culture detection methods for cerebrospinal fluid can improve pathogen detection rates.Adverse outcomes can be noted in more than 10% of PM cases.SP strains are high sensitivity to vancomycin,linezolid,meropenem,levofloxacin,moxifloxacin,rifampicin,and chloramphenicol.[Chinese Journal of Contemporary Pediatrics,2024,26(2):131-138]

Objective To explore the risk factors associated with cow's milk protein allergy(CMPA)in infants.Methods This study was a multicenter prospective nested case-control study conducted in seven medical centers in Beijing,China.Infants aged 0-12 months were included,with 200 cases of CMPA infants and 799 control infants without CMPA.Univariate and multivariate logistic regression analyses were used to investigate the risk factors for the occurrence of CMPA.Results Univariate logistic regression analysis showed that preterm birth,low birth weight,birth from the first pregnancy,firstborn,spring birth,summer birth,mixed/artificial feeding,and parental history of allergic diseases were associated with an increased risk of CMPA in infants(P＜0.05).Multivariate logistic regression analysis revealed that firstborn(OR=1.89,95％CI:1.14-3.13),spring birth(OR=3.42,95％CI:1.70-6.58),summer birth(OR=2.29,95％CI:1.22-4.27),mixed/artificial feeding(OR=1.57,95％CI:1.10-2.26),parental history of allergies(OR=2.13,95％CI:1.51-3.02),and both parents having allergies(OR=3.15,95％CI:1.78-5.56)were risk factors for CMPA in infants(P＜0.05).Conclusions Firstborn,spring birth,summer birth,mixed/artificial feeding,and a family history of allergies are associated with an increased risk of CMPA in infants.[Chinese Journal of Contemporary Pediatrics,2024,26(3):230-235]

Objective To investigate the risk factors for bronchopulmonary dysplasia(BPD)in twin preterm infants with a gestational age of<34 weeks,and to provide a basis for early identification of BPD in twin preterm infants in clinical practice.Methods A retrospective analysis was performed for the twin preterm infants with a gestational age of<34 weeks who were admitted to 22 hospitals nationwide from January 2018 to December 2020.According to their conditions,they were divided into group A(both twins had BPD),group B(only one twin had BPD),and group C(neither twin had BPD).The risk factors for BPD in twin preterm infants were analyzed.Further analysis was conducted on group B to investigate the postnatal risk factors for BPD within twins.Results A total of 904 pairs of twins with a gestational age of<34 weeks were included in this study.The multivariate logistic regression analysis showed that compared with group C,birth weight discordance of>25%between the twins was an independent risk factor for BPD in one of the twins(OR=3.370,95%CI:1.500-7.568,P<0.05),and high gestational age at birth was a protective factor against BPD(P<0.05).The conditional logistic regression analysis of group B showed that small-for-gestational-age(SGA)birth was an independent risk factor for BPD in individual twins(OR=5.017,95%CI:1.040-24.190,P<0.05).Conclusions The development of BPD in twin preterm infants is associated with gestational age,birth weight discordance between the twins,and SGA birth.