Skin injuries always disturb people's normal life, even seriously damage the body health. Thus, it is very necessary to use medical dressings to protect and treat skin wounds. Compared with traditional dressings, novel biological dressings develop more rapidly and their application scope is gradually expanding. Collagen is a natural biological material that can promote wound healing and it also has unique functional advantages in care and treatment. At present, collagen-based medical dressings has become one of the preferred choices to assist wound healing. The authors summarize the source, functional advantages and product classification of collagen-based dressings, and introduce the characteristics and applications of various collagen-based dressings, to provides a reference for further research of the collagen-based wound dressings.

Objective:The incidence of infections in patients with malignant hematologic diseases is extremely high and significantly affects their prognosis.Identifying early and precise biomarkers for infection is crucial for guiding the treatment of infections in these patients.Previous studies have shown that procalcitonin(PCT)can serve as an early diagnostic marker for bloodstream infections in patients with malignant hematologic diseases.This study aims to compare serum PCT levels in these patients with different pathogens,disease types,infection sites,and severity levels. Methods:Clinical data and laboratory results of infected patients with malignant hematologic diseases treated at the Department of Hematology,the Third Xiangya Hospital of Central South University from January 2018 to August 2023 were collected.General patient information was retrospectively analyzed.Serum PCT levels were compared among patients with different pathogens,types of malignant hematologic diseases,infection sites,and infection severity;Receiver operator characteristic(ROC)curves were used to determine the cut-off values and diagnostic value of serum PCT levels in diagnosing bloodstream infections versus local infections and severe infections versus non-severe infections.Mortality rates after 4-7 days of anti-infective treatment were compared among groups with rising,falling,and unchanged PCT levels. Results:A total of 526 patients with malignant hematologic diseases were included.The main pathogens were Gram-negative bacteria(272 cases,51.7%),followed by Gram-positive bacteria(120 cases,22.8%),fungi(65 cases,12.4%),viruses(23 cases,4.4%),and mixed pathogens(46 cases,8.7%).The main types of malignant hematologic diseases were acute myeloid leukemia(216 cases,41.1%),acute lymphoblastic leukemia(107 cases,20.3%),and lymphoma(93 cases,17.7%).Granulocyte deficiency was present in 68.3%(359 cases)of the patients during infection,with severe infection in 24.1%(127 cases).Significant differences in serum PCT levels were found among patients with different types of pathogens(P<0.001),with the highest levels in Gram-negative bacterial infections.Significant differences in serum PCT levels were also found among patients with different types of malignant hematologic diseases(P<0.05),with the highest levels in lymphoma patients.Serum PCT levels were significantly higher in systemic infections and severe infections compared to local infections and non-severe infections(both P<0.001).ROC curve analysis showed that the cut-off values for diagnosing bloodstream infections and severe infections were 0.22 and 0.28 ng/mL,with areas under the curve of 0.670 and 0.673,respectively.After 4-7 days of anti-infective treatment,the mortality rates of the PCT declining,PCT unchanged,and PCT rising groups were 11.9%,21.2%,and 35.7%,respectively,and pairwise comparisons were statistically significant(all P<0.05). Conclusion:PCT can be used as an auxiliary indicator for early identification of different pathogens,infection sites,and severity levels in patients with malignant hematologic diseases combined with infections.Dynamic monitoring of PCT levels after empirical antibiotic treatment provides important guidance for assessing patient's prognosis.

Purpose To evaluate the effect of PCSK9 gene knockout on myocardial function in obese mice via ultrasound strain technology,and to discuss the related mechanisms.Materials and Methods Twenty six-week-old wild-type C57BL/6 male mice were selected and randomly divided into a normal group(n=10)and an obese group(n=10).Additionally,ten six-week-old PCSK9-/-C57BL/6 male mice were selected as the PCSK9-/-group.Mice in the obese group and PCSK9-/-group were fed with high-fat feed to create models,while those in the normal group were fed with regular feed.After 12 weeks,mice that were successfully modeled were selected from the obese group and PCSK9-/-group.Then,the three groups of mice were subjected to cardiac ultrasound,transmission electron microscopy and immunofluorescence staining to observe relevant indicators.Results The interventricular septal end-diastolic thickness of mice in obese group,normal group,and PCSK9-/-group were(0.98±0.13)mm,(0.77±0.07)mm,(0.78±0.13)mm,respectively,with statistically significant difference(F=5.10,P=0.02).The obese group was thicker than the normal group(t=2.73,P＜0.05),while the PCSK9-/-group was thinner than the obese group(t=-2.92,P＜0.05).There were statistically significant differences in global longitudinal strain and global circumferential strain of the left ventricle among the three groups(F=7.44,15.40,P＜0.05),with the obese group showing a decrease in global longitudinal strain and global circumferential strain compared to the normal group(t=3.79,5.50,P＜0.05).The PCSK9-/-group showed an increase in global longitudinal strain and global circumferential strain compared to the obese group(t=-2.53,-3.37,P＜0.05).Electron microscopy and immunofluorescence results showed that the myocardial ultrastructure of the obese group was damaged,and the expression of NLRP3 and Caspase-1 were higher than that of the normal group(t=12.53,-4.73,P＜0.05),the myocardial ultrastructure damage in the PCSK9-/-group was significantly improved,the expression of NLRP3 and Caspase-1 were lower than that in the obese group(t=-6.23,2.05,P＜0.05).Conclusion Ultrasound strain can more sensitively detect changes in myocardial function in obese mice with PCSK9 gene knockout compared with conventional cardiac ultrasound parameters.Knockout of the PCSK9 gene may improve myocardial function in obese mice by inhibiting the expression of NLRP3 and Caspase-1.