[Objective] To analyze the loss rate of platelet donors and evaluate the strategies for establishing a platelet donor bank. [Methods] A total of 1 443 donors who joined the HLA and HPA gene donor bank for platelets in Henan Province from 2018 to 2020 were included in this study. Data on the total number of apheresis platelet donations, annual donation frequency, age at enrollment, donation habits (including the number of platelets donated per session and whether they had previously donated whole blood), and enrollment location were collected from the platelet donor information management system. Donor loss was determined based on the date of their last donation. The loss rates of different groups under various conditions were compared to assess the enrollment strategies. [Results] By the time the platelet bank was officially operational in 2022, 421 donors had been lost, resulting in an loss rate of 29% (421/1 443). By the end of 2023, the overall cumulative loss rate reached 52% (746/1 443). The loss rate was lower than the overall level in groups meeting any of the following conditions: total apheresis platelet donations exceeding 50, annual donation frequency of 10 or more, age at enrollment of 40 years or older, donation of more than a single therapeutic dose per session, or a history of whole blood donation two or more times. Additionally, loss rates varied across different enrollment locations, with higher enrollment numbers generally associated with higher loss rates. [Conclusion] Through a comprehensive analysis of donor loss, our center has adjusted its strategies for establishing the donor pool. These findings also provide valuable insights for other blood collection and supply institutions in building platelet donor banks.

BACKGROUND:For the replacement treatment of long-segment tracheal defects,although tissue engineering research has made some progress in recent years,it is still not perfect,and one of the biggest difficulties is that the hemodynamic reconstruction of the tracheal replacement cannot be achieved rapidly. OBJECTIVE:To preliminarily explore the potential of polycaprolactone scaffolds modified with exosome-loaded hydrogels to construct a rapidly vascularized tracheal substitute. METHODS:Exosomes were extracted from bone marrow mesenchymal stem cells of SD rats.After preparation of hyaluronic acid methacrylate solution,the exosome solution was mixed with hyaluronic acid methacrylate solution at a volume ratio of 1:1.Hyaluronic acid methacrylate hydrogels loaded with exosomes were prepared under ultraviolet irradiation for 5 minutes.The degradation of exosome-unloaded hydrogels and the controlled release of exosome-loaded hydrogels were detected.Polycaprolactone scaffolds were prepared by 3D printing.The pure hyaluronic acid methacrylate solution and the exosome-loaded hyaluronic acid methacrylate solution were respectively added to the surface of the scaffold.Hydrogel-modified scaffolds and exosome-modified scaffolds were obtained after ultraviolet irradiation.Thirty SD rats were randomly divided into three groups with 10 rats in each group and subcutaneously implanted with simple scaffolds,hydrogel-modified scaffolds and exosome-modified scaffolds,respectively.At 30 days after surgery,the scaffolds and surrounding tissues of each group were removed.Neovascularization was observed by hematoxylin-eosin staining and Masson staining and the expression of CD31 was detected by immunofluorescence. RESULTS AND CONCLUSION:(1)As time went by,the hydrogel degraded gradually,and the exosomes enclosed in the hydrogel were gradually released,which could be sustained for more than 30 days.The exosome release rate was faster than the degradation rate of the hydrogel itself,and nearly 20%of the exosomes were still not released after 30 days of soaking.(2)Under a scanning electron microscope,the surface of the simple polycaprolactone scaffold was rough.After hydrogel modification,a layer of gel was covered between the pores of the scaffold,and the scaffold surface became smooth and dense.(3)After 30 days of subcutaneous embedding,hematoxylin-eosin staining and Masson staining showed that more neovascularization was observed inside the scaffolds of the exosome-modified scaffold group compared with the hydrogel-modified scaffold group.The hydrogels on the scaffolds of the two groups were not completely degraded.Immunofluorescence staining showed that CD31 expression in the exosome-modified scaffold group was higher than that in the hydrogel-modified scaffold group(P<0.000 1).(4)These results indicate that hyaluronic acid methacrylate hydrogels can be used as controlled-release carriers for exosomes.The 3D-printed polycaprolactone scaffold modified by hyaluronic acid methacrylate hydrogel loaded with exosomes has good biocompatibility and has the potential to promote the formation of neovascularization.

Objective:To investigate the medical students' general understanding of online teaching and online learning of medical courses during the COVID-19 epidemic, and to analyze the satisfaction with online medical curriculum and its influencing factors.Methods:A total of 188 medical students in Xiangya School of Medicine of Central South University were investigated anonymously with a self-designed questionnaire. SPSS 26.0 was used for analyzing the relevant data, t test or variance analysis was conducted for coparison between groups, with test level α= 0.05. Results:The 88.83% (167) of the students believed that online teaching was much necessary, and the greatest advantage of online teaching was that they could arrange their learning time freely. However, 59.57%(112) of the students thought that the learning consciousness was reduced, and 49.47% (93) of the teachers were inadaptable to the change of teaching platform and 59.57% (112) teachers could not adapt to the change of teaching may be the main reasons affecting the teaching quality.Conclusion:Students have a high degree of acceptance of online teaching during the epidemic, but there are some problems such as decreased self-discipline, insufficient interaction between teachers and students, dissatisfaction with the construction of online course platform, inability to visit the laboratory and practice in the hospital, and so on. The investigation is still helpful to revise the medical education model in the post-epidemic period and the future. Our results suggest that the combination of online and offline teaching mode can be adopted in medical theory class and PBL discussion class, and at the same time, the construction of online learning resources for clinical practice and medical experiments should be strengthened.

Objective:To investigate the effect of arterialised Flow-through venous flap with palmaris longus tendon in repairing dorsal digit composite tissue defect.Methods:From March, 2010 to December, 2018, 23 cases (23 digits) of dorsal digit composite tissue defect were repaired with arterialised Flow-through venous flap with palmaris longus tendon. There were 17 males and 6 females aged between 23 to 53 (average, 37.2) years old. Causes of injury: 15 cases of strangulation, 5 of electric plane and 3 of thermal crush. Number of injured digit were 1 thumb, 11 index fingers, 9 middle fingers and 2 ring fingers. All of the injured digits had skin and extensor tendon defects with an area of 2.0 cm×1.8 cm-4.2 cm×2.6 cm, and the length of extensor tendon defect was 1.6-2.6 cm. One case had terminal and central tendon insertion defects and 5 suffered with terminal tendon insertion defect. Three cases were repaired by emergency surgery, and 20 were repaired by sub-emergency surgery. All donor sites were directly sutured. The shape, colour, texture, sensation, recovery of digit function and donor site appearance were followed-up at outpatient clinic.Results:The patients were followed-up for 8 to 23 (average, 11) months. The flap was soft, with mild pigmentation and recovery of protective sensation. The range of motion of the proximal and distal interphalangeal joints was 145°-170° (average,162.6°). According to Strickland hand function evaluation method, the results were excellent.Conclusion:The arterialised Flow-through venous flap with palmaris longus tendon is an ideal method in repair of the dorsal digit composite tissue defect.

Objective:To compare the difference and effect of fat grafting assisted by adjustable external volume expansion (EVE) and fat grafting only in female patients who chose autologous fat grafting for breast reconstruction after a breast cancer operation.Methods:A retrospective analysis was carried out in 17 patients in the past four years. The patients in the experimental group wore EVE 10 hours daily for four weeks before surgery, and the negative pressure value was -60 mmHg. From the second week after the operation, they continued to wear EVE 10 hours every day, and the initial negative pressure value was -40 mmHg. After one week, the negative pressure was adjusted to -20 mmHg, and the EVE was worn for four weeks after surgery. Both the experimental group and the control group chose classical Coleman fat for breast reconstruction.Results:The number of operations in the experimental and control groups was 3.0±0.8 and 3.9±1.2, respectively ( t=2.193; P<0.05). The single fat injection volume of the experimental group and the control group was (228.60±15.34) ml and (198.20±12.01) ml, respectively ( t=4.861; P<0.01). The single fat volume preservation rate of the experimental group and the control group was (31.6±5.8)% and (25.8±6.2)%, respectively ( t=2.226; P<0.05). For postoperative complications, there were 3 cases in the experimental group (10 cases in total) and 3 cases in the control group (7 cases in total). Conclusions:For breast cancer patients who choose autologous fat grafting for breast reconstruction, wearing EVE can reduce the number of operations, improve the single fat injection volume and postoperative fat preservation rate, and reduce postoperative complications.

Objective:To investigate the medical students' general understanding of online teaching and online learning of medical courses during the COVID-19 epidemic, and to analyze the satisfaction with online medical curriculum and its influencing factors.Methods:A total of 188 medical students in Xiangya School of Medicineof Central South University were investigated anonymously with a self-designed questionnaire. SPSS 26.0 was used for analyzing the relevant data, t test or variance analysis was conducted fro coparison between groups. The data was described with rate and there was a significant difference when P<0.05.Results:The 88.83% of the students believed that online teaching was much necessary, and the greatest advantage of online teaching was that they could arrange their learning time freely. However, 59.57% of the students thought that the learning consciousness was reduced, and inadaptability to the change of teaching platform (49.47%) and teaching mode of teachers (59.57%) may be the main reasons affecting the teaching quality.Conclusion:Students have a high degree of acceptance of online teaching during the epidemic, but there are some problems such as decreased self-discipline, insufficient interaction between teachers and students, dissatisfaction with the construction of online course platform, inability to visit the laboratory and practice in the hospital, and so on. The investigation is still helpful to revise the medical education model in the post-epidemic period and the future. Our results suggest that the combination of online and offline teaching mode can be adopted in medical theory class and PBL discussion class, and at the same time, the construction of online learning resources for clinical practice and medical experiments should be strengthened.

Objective: To explore the correlation between screen time, exposure time to different screens and psychology behaviors of preschool children. Methods: A total of 2 582 children from kindergartens in urban Xuzhou areas were recruited to perform the physical examination, a cluster sampling method being explored. Parent questionnaires were performed to understand the time of screens and children’s psychology behaviors. Multi-linear regression and Logistic regression models were also used to analyze the correlation between them in preschool children. Results: The prevalence of abnormal internalization behavior of preschool children in Xuzhou City was 3.8%, the detection rate of abnormal externalization behavior was 22.4%, and the detection rate of prosocial behavior abnormality was 20.9%. The time spent by the preschool boys on TV time, learning day screen time and one-week video time is significantly higher than the girls (P<0.05). After adjusting for age and gender, the results of multiple linear regression analysis showed that the longer the average screen time, the more serious the problem of internalizing and externalizing problems; and the longer the average screen time of the weekend and the week, the worse the prosocial behavior of children (P<0.05). After correcting multiple covariates, it was found that the average screen time was positively correlated with children’s internal and external behavioral problems (P<0.05). Logistic regression analysis showed that after adjusting for age and gender, the average screen time of study day, weekend and week was a risk factor for preschool children’s internal and external behavior problems, and the average weekly screen time was a protective factor for prosocial behavior (P<0.05). After adjusting for multiple covariates, the learning day and the average weekly screen time were risk factors for children’s internal and external behavior (P<0.05). In addition, the results of association analysis between different types of video time exposure and psychological behavior showed that after adjusting for age and gender, all types of video exposures affected the internal and external behaviors of patients (P<0.05); after correcting multiple covariates The association was still statistically significant (P<0.05). Logistic regression analysis showed that after adjusting for age and gender, the exposure time of each type of video screen was a risk factor for children’s internal and external behavior problems (P<0.05). After correcting multiple covariates, all types of video exposure were internalized behavior problems. The risk factors, and the video time of other electronic products were risk factors for externalization behavior problems (P<0.05). Conclusion Average screen time has a significant positive correlation with psychological behavior, and the exposure time of screens such as TV and mobile phone could increase the incidence of psychological behaviors in preschool children.

OBJECTIVE: To compare the histopathological features of the synovium between rheumatoid arthritis (RA) and osteoarthritis (OA). METHODS: We retrospectively analyzed the synovial specimens obtained after synovial surgery in 72 cases of RA and 24 cases of OA. Two independent pathologists reviewed the sections of the synovial tissues with HE staining, quantitatively scored the degree of fibroblast-like synoviocyte (FLS) hyperplasia, vascular hyperplasia, fibroplasia, and lymphocyte infiltration, and examined the presence plasma cell infiltration. The pathological morphology of the synovial tissues was evaluated in relation with the clinical data of the patients. RESULTS: Pannus formation was also detected in the synovium of OA patients, which showed a lesser degree of OA-FLS hyperplasia, fibrosis and lymphocyte infiltration and a significantly lower rate of plasma cell infiltration compared with the pannus in RA patients. Vascular proliferation was also milder in the pannus of OA patients than in RA pannus, but the difference was not statistically significant. In OA patients, the pannus could be observed under a microscope and was difficult to distinguish from that in RA patients. CONCLUSIONS Pannus formation occurs also in the synovium of OA patients but with milder FLS hyperplasia, fibrosis and lymphocyte infiltration and a lower rate of plasma cell infiltration compared with the pannus in RA patients. These differences in the pannus between OA and RA can be of potential value in the diagnosis and treatment of the patients.
Arthritis, Rheumatoid ; Cells, Cultured ; Humans ; Osteoarthritis, Knee ; Retrospective Studies ; Synovial Membrane

Objective To compare the PCR effect of rapid PCR instrument and common PCR instrument. Methods The concentration of 9947A standard was diluted to 0.1, 0.05, 0.025, 0.0125, 0.0063 ng/μL, 100 samples from each concentration group to establish PCR reaction system with Identifiler? Plus PCR Amplification Kit, 50 samples of them test with rapid PCR instrument (Speed cycler2 thermocycler), the other 50 samples test with common PCR instrument (9700 thermocycler). Detection of PCR product with 3500xL Genetic Analyser, the STR typing of both groups of each concentration group should be compared. Results The success rate of both thermocyclers have no significant difference (P>0.05); The success number of STR typing of common PCR instrument (13.7±1.0; 11.3±1.5) were higher than rapid PCR instrument (13.1±1.3; 9.9±1.9) when the concentration of 9947A were 0.0125, 0.0063ng/μL (P=0.029; P<0.001); The peak height of DNA typing map obtained from common PCR instrument (18931±4625;13437±3165; 5752±1344) were higher than rapid PCR instrument (16929±4034; 11815±4120; 4865±1401) when the concentration of 9947A were 0.1, 0.05, 0.025ng/μL (P=0.023; P=0.030; P=0.002). Conclusions The rapid PCR instrument could achieve the equal success rate to the common PCR instrument with less time, which revealed that the rapid PCR instrument was suitable for application in practical cases; The quality of STR typing from common PCR instrument may be more higher.

Objective To discuss the effect of DNA extraction of bloodstain on the filter paper with four methods of solid phase absorption.Methods 180 bloodstain samples on the iflter paper, each one contains 1 microlitre anticoagulation peripheral venous blood, divided into 4 groups with 45 samples, respectively. All samples were treated with four methods of solid phase absorption, i.e. DNA IQ? System, D-shield sensitive DNA Extraction Kit, High efficiency Silica Bead DNA Extraction Kit and Conventional silica bead method. The concentration of DNA and the results of STR typing of four groups were compared each other.Results The concentration of DNA was 3.764±1.790μg/mL and 3.634±1.112μg/mL by using D-shield sensitive DNA Extraction Kit and High efifciency Silica Bead DNA Extraction Kit, respectively. However, the concentration of DNA by using Conventional silica bead method group (3.350±1.250) was not signiifcantly different from each other (P<0.05), while the concentration of DNA extracted with above three methods were higher than by using DNA IQ? System (1.864±1.207)(P<0.001); Signiifcant differences of peak height existed between DNA IQ? System and other three methods (P<0.001); As the same time, the peak height of samples by using High efficiency Silica Bead DNA Extraction Kit and Conventional silica bead method were signiifcantly different from D-shield sensitive DNA Extraction Kit (P<0.01).Conclusions The DNA extracted in bloodstain on the iflter paper by using D-shield sensitive DNA Extraction Kit, High efifciency Silica Bead DNA Extraction Kit and Conventional silica bead method was more than DNA IQ? System. Meanwhile, the quality of DNA using High efifciency Silica Bead DNA Extraction Kit and Conventional silica bead method may be higher.