To construct a recombinant expression system for a single-domain antibody targeting the urease of Helicobacter pylori (Hp), this study employed several strategies. First, using artificial intelligence (AI) auxiliary tools such as Pymol, I-TASSER, and ClussPro2, the molecular interactions between different antibodies and Hp urease subunit B (UreB) were analyzed. The fully humanized single-domain antibody UreBAb was identified as the primary research target. Next, the UreBAb gene sequence was optimized based on Escherichia coli codon preferences, and was inserted into expression vectors such as pET28a and pE-SUMO. The resulting recombinant expression strains were obtained by transforming Escherichia coli Rosetta(DE3). Recombinant antibody proteins were prepared through IPTG induction, and its activity was detected using extracted Hp urease as the antigen. SDS-PAGE analysis confirmed the correct expression of both UreBAb and SUMO-UreBAb, with protein yields of 0.34 mg/mL and 0.41 mg/mL, respectively. Unidirectional immunodiffusion experiments further confirmed that both recombinant antibodies exhibited strong affinity for Hp UreB antigen, with inhibition rates of 51.27% and 74.07%, respectively. Additionally, leveraging artificial intelligence tools such as AlphaFold2, cluspro2, mCSM-AB, OSPREY, and FoldX, the study evaluated and analyzed key binding sites and mutational strategies affecting the stability of the antigen-antibody complex. Subsequently, nine UreBAb evolution mutants were constructed, and their binding activities with the antigen were enhanced. Among these, the I107W mutant showed the most significant improvement, achieving a 24.95% increase compared to the wild-type UreBAb. This research lays a solid foundation for the development of fully humanized single-domain antibodies against Hp.

Purpose To assess the feasibility of nuclear score combined with ultrasound features on indeterminate thyroid nodules in fine needle aspiration cytological diagnosis.Methods A consecutive cohort of 119 thyroid fine-needle aspiration(FNA)specimens with indeterminate diagnosis(TBSRTC cate-gory Ⅲ-Ⅴ)and available histopathologic follow-up was evalua-ted.Original sonographic images and cytological slides of each nodule were reviewed by two experienced sonographers and two experienced cytopathologists respectively,and evaluated jointly to obtain consensus.The identification of the optimal cut-off points of simplified nuclear score and ultrasound features score for the diagnosis of malignancy or low-risk neoplasm were evalu-ated using the receiver operating characteristic(ROC)curves and the assessment of the area under the ROC curve(AUC).The specificity,sensitivity,positive predictive value(PPV)and negative predictive value(NPV)of nuclear score and US score were evaluated from crosstabs based on Cut-off points and signif-icance were calculated.The diagnostic accuracy of simplified nuclear score combined with ultrasound features was estimated by Logistic regression and ROC curve analysis.Results Nucle-ar grooves,intra-nuclear inclusions and chromatin clearing were more common in malignancy/low-risk neoplasms(P = 0.001,0.013 and 0.001 respectively).A Cut-off point of≥2 for the simplified nuclear score was sensitive for defining malignancy/low-risk neoplasm,and the sensitivity was 99.1%.Nodule height greater than width,absent halo sign,irregular margin and absent intranodular vascularization were more common in malig-nancy/low-risk neoplasms(P = 0.003,0.007,0.003 and 0.004 respectively).When the Cut-off point was set as≥5,the PPV and specificity for defining malignancy/low-risk neoplasm were 95.9%and 78.6%respectively.ROC curve analysis showed that the diagnostic accuracy of nuclear score combined with US score(0.873,95%CI = 0.777-0.970)was higher than that of nuclear score alone(0.817,95%CI = 0.687-0.948,P =0.092)or US score alone(0.758,95%CI 0.637-0.879,P =0.047).But no significant difference was detec-ted between the combined score and the nuclear score.Conclu-sion The addition of simplified nuclear score and US score to FNA cytology can increase the diagnostic accuracy of cytology in indeterminate categories.

Objective:To analyze the clinical characteristics of elderly patients with papillary thyroid cancer(PTC)by age grouping.Methods:The patients were divided into three groups according to age at diagnosis: old(≥60 years, 90 cases), middle(40-59 years, 359 cases)and young patients(<40 years, 203 cases). The clinical data of 652 patients with PTC who were admitted to the Department of Thyroid Surgery of Beijing Hospital from December 2019 to December 2021 were retrospectively analyzed.The patients were divided into elderly group(≥60 years old, 90 cases), middle-aged group(40-59 years old, 359 cases)and young group(<40 years old, 203 cases). The clinical characteristics, ultrasound characteristics and invasion-related factors of patients in different groups were analyzed by statistical methods.Results:Compared with the young and middle-aged group, the elderly patients with PTC had a higher proportion of microcarcinoma(75.6%, 75.2%, 61.4%, χ2=13.054, P=0.001), less cervical lymph node metastasis(24.4%, 34.3%, 58.1%, χ2=41.650, P<0.001), and lower proportion of metastatic lymph nodes(0.08, 0.14, 0.24, χ2=40.618, P<0.001). There was no significant difference in tumor location and extra glandular invasion among the three age groups(35.56%, 36.2%, 38.4%, χ2=0.959, P=0.545). Conclusions:Compared with the young and middle-aged groups, PTC showed low invasiveness in the elderly population.In addition to surgical treatment, for elderly patients with low-risk clinical characteristics, it is worth performing a further study on whether careful observation or palliative treatment can be selected after comprehensive evaluation.