Objective To explore the practice effect of problem-based learning(PBL) in teaching of pathogen biology and immunology at college level.Methods Three-year clinical majors of class 1 and 2 in Luohe Medical College were chose,class 1 as PBL experimental group(n=100) and class 2 as control group(n=100).Chapter of hepatitis virus was taught respectively using PBL and LBL teaching method.Teaching effect was evaluated by test and questionnaire.Teaching effects between PBL and LBL were compared.SPSS 13.0 was used to do statistical analysis and data were expressed as percentage.Chi-square test was performed and P＜0.05 shows statistically significant differences.Results Results of test showed that excellent and passing rates were higher in PBL group than in LBL group(P=0.000) ; flunked rate was lower in PBL group than in LBL group(P=0.000).Results of questionnaire showed that more than 80％ students thought that PBL can mobilize students' initiatives of learning,train cooperation consciousness and enhance language skills,etc.Conclusions PBL can be used in pathogen biology and immunology for 3-year clinical majors and deserves further application.

Objective To observe the inhibiting activities of fibronectin (FN) and citrullinated fibronectin (cFN) on disintegrin and metalloproteinase with thrombospondin motifs-4 (ADAMTS-4),and to explore the extracellular regulative mechanisms of ADAMTS-4.Methods FN was incubated with peptidylarginine deaminase type 4 (PADI4).Western blotting analysis was used to verify the citrullination of FN.The binding activity of FN and cFN to ADAMTS-4 were investigated by enzyme-linked immunosorbent assay (ELISA).The proteolytic ability of ADAMTS-4 after binding to FN and cFN were measured with the aggrecanase activity assay kit.One-way ANOVA,LSD-t test and t-test were used for statistical analysis.Results The immunosignal of citrulline was detected in FN after incubated with PADI4,but not in the absence of PADI4.A higher absorbance at 405 nm was detected when the full-length ADAMTS-4 protein was incubated with FN (2.182±0.042) than cFN (0.624±0.033; t=50.522,P＜0.01).Additionally,the recombinant ADAMTS-4 protein with a truncation at the C-terminus displayed low absorbance at 405 nm when the enzyme was incubated with both FN(0.971±0.024) and cFN(0.934±0.012; t=2.388,P＞0.05).Large amounts of ARGxx peptide were detected with full-length ADAMTS-4 in aggrecanase activity assay [(0.908±0.088) nmol/L],but significantly less when in the presence of FN and ADAMTS-4 [(0.573±0.000) nmol/L,P＜0.05].The production of this peptide was more when full-length ADAMTS-4 was incubated with cFN [(0.830±0.020) nmol/L,P＜0.05] than with FN.The reaction containing the truncated ADAMTS-4 without FN or cFN yielded the highest concentration of ARGxx peptide [(36.420±3.673) nmol/L],peptide production was not significantly altered when FN [(41.099±0.101) nmol/L] or eFN [(41.064±0.083) nmol/L] were added to the reaction.Conclusion FN could bind to ADAMTS-4 and inhibit its proteolytic activity.After citrullinated by PADI4,the binding activity of cFN is weakened and less inhibition to ADAMTS-4.

Objective:To explore the curative effects of medial plantar free flap in reconstructing electric burn wound and scar contracture in the palm.Methods:A retrospective observational study was conducted. From January 2020 to January 2023, 6 patients with electric burn wounds or scar contracture in the palm who met the inclusion criteria were admitted to the First Affiliated Hospital of Air Force Medical University, including 5 males and 1 female, aged 35 to 55 years. The wound area was 5.0 cm×3.0 cm-8.0 cm×7.0 cm after the debridement of electric burn wounds or resection of scar in the palm. The medial plantar free flap anastomosed with cutaneous nerve was used for wound reconstruction, with flap area of 5.5 cm×3.5 cm-8.5 cm×7.5 cm. The wound in the donor site was repaired with transplantation of abdominal full-thickness skin graft. After surgery, the survival of flaps and skin grafts were observed, the shape and texture of flap and the recovery of donor site of flap were observed, and the holding function of the affected hand was assessed. At the last follow-up, the two-point discrimination distance of flap was measured, the sensory recovery of flap was evaluated with the trial standard for the evaluation of the functions of the upper limbs of the Hand Surgery Society of the Chinese Medical Association, and the function recovery of flap was evaluated by post-surgery flap function evaluation scale.Results:After surgery, 5 flaps survived well, while the distal part of 1 flap was partially necrotic, which was repaired by medium-thickness skin graft from lateral thigh after debridement. All the skin grafts at the donor sites survived well. During follow-up of 3 to 24 months, the flap was not bloated, the texture and color were good, the match with the surrounding tissue was high, with no obvious scar contracture occurred at the donor site. The affected hand had good holding function. At the last follow-up, the two-point discrimination distance of flap was 6-8 mm, the flap sensation recovery was as follows: 5 flaps recovered to grade S3 +, 1 flap recovered to grade S3, and the functional evaluation of flaps was excellent in 5 cases and good in 1 case. The patients basically returned to normal life and work. Conclusions:The medial plantar free flap with cutaneous nerve anastomosis has many advantages, such as high matching degree of appearance, good sensory recovery, and holding function of the affected hand. It is an ideal choice for the reconstruction of the electric burn wound and scar contracture in the palm.