[Establishment and validation of a risk prediction model for disseminated intravascular coagulation patients with electrical burns]

Objective: To establish and validate a risk prediction model of disseminated intravascular coagulation (DIC) by the screening independent risk factors for the occurrence of DIC in patients with electrical burns. Methods: The retrospective case series study was conducted. The clinical data of 218 electrical burn patients admitted to Baogang Hospital of Inner Mongolia from January 2015 to January 2023 who met the inclusion criteria were collected, including 198 males and 20 females, with the age of (38±14) years. The patients were divided into DIC group and non DIC group based on whether they were diagnosed with DIC during the treatment period. The following data of patients of two groups were collected and compared, including age, gender, total burn area, full-thickness burn area, injury voltage, whether osteofascial compartment syndrome occurred within 1 day after injury, duration of stay in burn intensive care unit, total length of hospital stay, whether combined with inhalation injury and multiple injuries, whether shock occurred upon admission, the abbreviated burn severity index score, and the acute physiology and chronic health evaluation Ⅱ score. The laboratory examination data of the patients within 24 hours after admission were also collected, including blood routine indexes: white blood cell count (WBC), hemoglobin level, platelet count (PLT), and neutrophil count; coagulation indexes: activated partial thromboplastin time (APTT), prothrombin time, thrombin time, and levels of D-dimer and fibrinogen (FIB); blood biochemistry indexes: aspartic transaminase, alanine transaminase, direct bilirubin, total bilirubin, total protein, albumin, blood glucose, creatinine, and urea nitrogen; blood gas analysis indexes: blood pH value, arterial partial pressure of oxygen, arterial partial pressure of carbon dioxide, bicarbonate, and base excess; and cardiac zymogram indexes: levels of myoglobin, troponin, lactate dehydrogenase, creatine kinase (CK), and α-hydroxybutyrate dehydrogenase. Data were statistically analyzed with chi-square test, Fisher's exact probability test, independent sample t test, and Mann-Whitney U test. For the variables with statistically significant differences in single factor analysis, the least absolute value selection and shrinkage operator (LASSO) regression was used to reduce the dimension, and the predictive factors for DIC in 218 patients with electrical burns were screened. The above-mentioned predictors were included in multivariate logistic regression analysis to find out the independent risk factors for DIC in 218 patients with electrical burns, and to draw the prediction model nomograms. The performance of the prediction model was evaluated by the receiver operating characteristic (ROC) curve and the area under the ROC curve, and the prediction model was validated by the calibration curve and clinical decision curve analysis (DCA). Results: Compared with those in non DIC group, the total burn area, full-thickness burn area, total length of hospital stay, and the proportions of high voltage caused injury, occurrence of osteofascial compartment syndrome within 1 day after injury, combination of inhalation injury, and occurrence of shock upon admission of patients in DIC group were significantly increased/prolonged (with Z values of -2.53, -4.65, and -2.10, respectively, with χ2 values of 11.46, 16.00, 7.98, and 18.93, respectively, P<0.05). Compared with those in non DIC group, the APTT, level of D-dimer, myoglobin, WBC, PLT, and levels of FIB, total bilirubin, and CK of patients within 24 hours after admission in DIC group were significantly prolonged/increased (with Z values of -2.02, -4.51, and -3.82, respectively, with t values of -3.84, -2.34, -2.77, -2.70, and -2.61, respectively), and the level of total protein and blood pH value were significantly reduced (t=-2.85, Z=-2.03), P<0.05. LASSO regression analysis was carried out for the above 17 indicators with statistically significant differences. The results showed that injury voltage, the occurrence of shock upon admission, the occurrence of osteofascial compartment syndrome within 1 day after injury, and levels of D-dimer and total protein within 24 hours after admission were predictive factors for the occurrence of DIC in 218 patients with electrical burns (with regression coefficients of 0.24, 0.52, 0.35, 0.13, and -0.001, respectively). Multivariate logistic regression analysis showed that injury voltage, the occurrence of shock upon admission, the occurrence of osteofascial compartment syndrome within 1 day after injury, and D-dimer level within 24 hours after admission were independent risk factors for DIC in 218 patients with electrical burns (with odds ratios of 3.33, 4.24, 2.68, and 1.38, respectively, with 95% confidence intervals of 1.43-7.79, 1.78-10.07, 1.17-6.13, and 1.19-1.61, respectively, P<0.05). Based on the aforementioned four independent risk factors, the nomogram of prediction model for evaluating the probability of DIC in patients was drawn. The area under the ROC curve of prediction model was 0.88, and the 95% confidence interval was 0.82-0.95, indicating that the model had good predictive ability; the curve of prediction model tended to be near the ideal curve, indicating that the model had a high calibration degree; the clinical DCA of prediction model showed that the threshold probability of patients ranged from 4% to 97%, indicating that the model had good predictive ability. Conclusions: The injury voltage, the occurrence of shock upon admission, the occurrence of osteofascial compartment syndrome within 1 day after injury, and D-dimer level within 24 hours after admission are independent risk factors for the occurrence of DIC in patients with electrical burns. The prediction model established based on the above indicators can provide early warning for the occurrence of DIC in these patients.

[Research advances of natural biomaterials in promoting wound repair]

Acute and chronic wounds seriously threaten patients' life health and quality of life, therefore, wound repair has become a hot topic of research for scholars at home and abroad in recent years. With the development of material science and tissue engineering, more and more biomaterials prepared from natural ingredients were used in basic research and clinical treatment of wound repair. Such biomaterials can be used as templates for wound tissue regeneration to induce autologous cell adhesion and migration, and promote the deposition of extracellular matrix, which have broad clinical application prospects. This paper reviews the characteristics and application advance of natural biomaterials which are popular in the field of wound repair, aiming to provide ideas for the research and development of new wound dressing and tissue engineering skin.

[Clinical effects of ultra-pulsed fractional carbon dioxide laser in the treatment of mild to moderate microstomia after burns]

Objective: To investigate the clinical effects of ultra-pulsed fractional carbon dioxide laser (UFCL) in the treatment of mild to moderate microstomia after burns. Methods: A retrospective observational study was conducted on 19 patients with mild to moderate microstomia after burns who were admitted to Inner Mongolia Baogang Hospital from January 2018 to January 2022, including 15 males and 4 females aged (35±14) years. Patients had an average course of 71 d of microstomia, with 8 cases of moderate microstomia and 11 cases of mild microstomia. All the patients received UFCL treatment every 2-3 months until the microstomia was corrected or the treatment bottleneck was reached. The times of UFCL treatment for patients and the time interval from the last treatment to the last follow-up were recorded. Before the first treatment and at the last follow-up, the opening degree of mouth (finger measurement method), oral gap width, and the distance between the upper and lower incisors during mouth opening were recorded. Before the first treatment and at the last treatment, the new Vancouver scar scale (VSS) was used to evaluate the scar. At the last follow-up, the degree of satisfaction was evaluated by the Likert 5 scale by the patients themselves, and the satisfaction ratio was calculated; the adverse reactions such as pigmentation, blisters, infection, and persistent erythema in the treatment area were counted. Data were statistically analyzed with Mann-Whitney rank sum test or paired sample t test. Results: Patients received UFCL treatment of 3 (2, 6) times. The interval from the last treatment to the last follow-up was 26 months at most and 4 months at least. At the last follow-up, the opening degree of mouth of patients was significantly improved than that before treatment (Z=4.68, P<0.01). At the last follow-up, the oral gap width of patients was (35±6) mm, and the distance between upper and lower incisors during mouth opening was (3.2±0.4) cm, which was significantly improved compared with those before treatment (with t values of 10.73 and 18.97, respectively, P<0.01). The VSS score after the last treatment was 4.1±1.6, which was significantly better than that before treatment (t=22.96, P<0.01). At the last follow-up, the satisfaction ratio of patients with treatment was 18/19, and no pigmentation, blisters, infection, persistent erythema, and other adverse reactions of all patients in the treatment area occurred, however, one of the patients reported that the disease recurred about half a year after treatment. Conclusions: UFCL is an effective method for treating mild to moderate microstomia after burns, with which patients are highly satisfied, and it is worth of further study and promotion.

[Outcomes at discharge of preterm infants born <34 weeks' gestation]

Objective: To investigate the incidence and trend of short-term outcomes among preterm infants born <34 weeks' gestation. Methods: A secondary analysis of data from the standardized database established by a multicenter cluster-randomized controlled study "reduction of infection in neonatal intensive care units (NICU) using the evidence-based practice for improving quality (REIN-EPIQ) study". This study was conducted in 25 tertiary NICU. A total of 27 192 infants with gestational age <34 weeks at birth and admitted to NICU within the first 7 days of life from May 2015 to April 2018 were enrolled. Infants with severe congenital malformation were excluded. Descriptive analyses were used to describe the mortality and major morbidities of preterm infants by gestational age groups and different admission year groups. Cochran-Armitage test and Jonckheere-Terpstra test were used to analyze the trend of incidences of mortality and morbidities in 3 study-years. Multiple Logistic regression model was constructed to analyze the differences of outcomes in 3 study-years adjusting for confounders. Results: A total of 27 192 preterm infants were enrolled with gestational age of (31.3±2.0) weeks at birth and weight of (1 617±415) g at birth. Overall, 9.5% (2 594/27 192) of infants were discharged against medical advice, and the overall mortality rate was 10.7% (2 907/27 192). Mortality for infants who received complete care was 4.7% (1 147/24 598), and mortality or any major morbidity was 26.2% (6 452/24 598). The incidences of moderate to severe bronchopulmonary dysplasia, sepsis, severe intraventricular hemorrhage or periventricular leukomalacia, proven necrotizing enterocolitis, and severe retinopathy of prematurity were 16.0% (4 342/27 192), 11.9% (3 225/27 192), 6.8% (1 641/24 206), 3.6% (939/25 762) and 1.5% (214/13 868), respectively. There was a decreasing of the overall mortality (P<0.001) during the 3 years. Also, the incidences for sepsis and severe retinopathy of prematurity both decreased (both P<0.001). However, there were no significant differences in the major morbidity in preterm infants who received complete care during the 3-year study period (P=0.230). After adjusting for confounders, infants admitted during the third study year showed significantly lower risk of overall mortality (adjust OR=0.62, 95%CI 0.55-0.69, P<0.001), mortality or major morbidity, moderate to severe bronchopulmonary dysplasia, sepsis and severe retinopathy of prematurity, compared to those admitted in the first study year (all P<0.05). Conclusions: From 2015 to 2018, the mortality and major morbidities among preterm infants in Chinese NICU decreased, but there is still space for further efforts. Further targeted quality improvement is needed to improve the overall outcome of preterm infants.

[Research advances on signaling pathways affecting sweat gland development and their involvement in the reconstitution of sweat adenoid cells in vitro]

The damage of sweat glands in patients with extensive deep burns results in the loss of thermoregulation, which seriously affects the quality of life of patients. At present, there are many researches on the repair of sweat gland function, but the mechanism of human sweat gland development has not been fully clarified. More and more studies have shown that the cascaded pathways of Wnt/β-catenin, ecto- dysplasin A/ectodysplasin A receptor/nuclear factor-κB, sonic hedgehog, and forkhead box transcription factor jointly affect the development of sweat glands, and it has been reported that the cascaded signaling pathways can be used to achieve the reconstruction of sweat adenoid cells in vitro. This article reviews the signaling pathways that affect the development of sweat glands and their involvement in the reconstruction of sweat adenoid cells in vitro.

[Transplantation of compound tissue flap of toe to reconstruct the thumb with necrosis caused by electric burns in four patients]

From January 2010 to December 2017, 4 patients of thumb with necrosis caused by electric burns (all male, aged from 31 to 58 years) were admitted to our hospital, with 1 patient of second degree injury of right thumb, 2 patients of third degree injury of right thumb, and 1 patient of third degree injury of left thumb. Routine debridement under general anesthesia was performed within 7 days after injury. The compound tissue flap of contralateral second toe was transplanted to reconstruct the thumb with third degree defect, and compound tissue flap of ipsilateral distal hallex was transplanted to reconstruct the thumb with second degree defect. Dorsalis pedics artery was anastomosed with radial artery, saphenous vein or dorsalis pedics vein was anastomosed with cephalic vein. The donor site was transplanted with split-thickness skin graft from autologous thigh. All the tissue flaps and skin grafts survived in 2 weeks after surgery. Within 1 year of follow-up, the reconstructed thumbs can achieve radial abduction and palmar abduction with good function. Reconstruction of thumb with free transplantation of compound tissue flap of toe is a good method to repair thumb with necrosis caused by electric burn.

[Effects of allogeneic mouse adipose-derived mesenchymal stem cell-microporous sheep acellular dermal matrix on healing of wound with full-thickness skin defect in mouse and the related mechanism]

Objective: To explore the allogeneic mouse adipose-derived mesenchymal stem cell (ADSC)-microporous sheep acellular dermal matrix (ADM) on healing of wound with full-thickness skin defect in mouse and the related mechanism. Methods: One Kunming mouse was sacrificed by cervical dislocation to collect adipose tissue from inguinal region. Mouse ADSCs were isolated from the adipose tissue and cultured in vitro. Cells of the third passage were identified by cell adipogenic and osteogenic differentiation. The expressions of CD73, CD90, CD105, and CD34 were analyzed by flow cytometry. After one sheep was sacrificed, microporous sheep ADM was prepared from sheep back using decellularization method and freezing-thawing method. A 12 mm diameter, round, full-thickness skin defect wound was made on the back of each one of 36 Kunming mice. The wounds were covered by microporous sheep ADM. The mice were divided into group ADSC and control (C) group with 18 mice in each group according to the random number table after surgery. A volume of 0.2 mL DMEM/F12 culture medium containing 1×10(6) ADSCs was injected between microporous sheep ADM and wound of mice in group ADSC. While 0.2 mL DMEM/F12 culture medium was injected between microporous sheep ADM and wound of mice in group C. On post surgery day (PSD) 12 and 17, wound healing rates of mice in the 2 groups were calculated. On PSD 7, 12, and 17, wound vascularization of mice in the 2 groups was observed under reverse irradiation of backlight. On PSD 7, 12, and 17, the wound granulation tissue of mice in group ADSC was observed by hematoxylin and eosin staining. On PSD 7, the thicknesses of granulation tissue of mice in the 2 groups was measured. On PSD 12 and 17, expressions of VEGF in wounds of mice in the 2 groups were detected by immunohistochemical method. The sample number was 6 in each group at each time point in the above experiments. Data were processed with t test and analysis of variance of factorial design. Results: (1) After 7 days of adipogenic induction, lipid droplet was observed in cytoplasm using oil red O staining. After 21 days of osteogenic induction, black deposits of calcium salts were detected using silver nitrate staining. Expression rates of CD73, CD90, CD105, and CD34 in cells were 97.82%, 99.32%, 97.35%, and 5.88% respectively. The cells were identified as ADSCs. (2) The wound healing rates of mice in group ADSC on PSD 12 and 17 [(78±6)%, (98±3)%] were significantly higher than those in group C [(60±9)%, (90±4)%, t=4.26, 4.46, P<0.01]. (3) On PSD 7, no vessel obviously grew into the center of wounds of mice in the 2 groups, while the granulation tissue has covered the wounds of mice in group ADSC. On PSD 12, the vessels were more abundant in wounds of mice in group ADSC than those in group C. On PSD 17, big vessels crossing the whole wounds was observed in wounds of mice in group ADSC, while big vessels were observed without crossing the whole wounds in wounds of mice in group C. (4) The wounds were covered with thin granulation tissue on PSD 7, and the granulation tissue began to thicken on PSD 12 and were covered by epidermis on PSD 17 in wounds of mice in group ADSC. On PSD 7, the granulation tissue in wounds of mice in group ADSC [(0.62±0.05) mm] was significantly thicker than that in group C [ (0.31±0.04) mm, t=12.27, P<0.01]. (5) On PSD 12 and 17, expressions of VEGF in wounds of mice in group ADSC [(80.7±2.2), (0.98±0.03)/mm(2)] were significantly than those in group C [(59.5±2.4), (81.5±2.6)/mm(2,) t=15.95, 14.14, P<0.01]. Conclusions: Allogeneic mouse ADSC-microporous sheep ADM can accelerate angiogenesis and growth of granulation tissue, thus promoting wound healing, which may be due to the increase of expression of VEGF.

[Advances in the research of basic study and clinical application of adipose-derived mesenchymal stem cells]

Since the discovery of adipose-derived mesenchymal stem cell (ADSC) in more than ten years, a great progress has been made from its basic research to clinical application. Compared with bone marrow mesenchymal stem cells, ADSCs are more abundant in reserve, easier to obtain with fewer injuries and less complications. These cells have multiple differentiation potential and can differentiate into adipocytes, chondrocytes and osteoblasts with the influence of different inducing factors. Early studies of ADSCs mainly focused on the ability of multi-directional differentiation, espe-cially on the regeneration of bone defects and cartilage tissue. At present, the researches mainly focus on immunoregulation and paracrine function of ADSCs. Although ADSCs have made a great progress in clinical application, the cell preparation, use pattern, and mechanisms in clinical treatment are not clear. This paper elaborates on these issues.

Dynamic changes of virus load in supernatant of primary CEK cell culture infected with different generations of avian infectious bronchitis virus strains Sczy3 as revealed by real-time reverse transcription-polymerase chain reaction

Infectious bronchitis virus (IBV) can multiply effectively in chick embryo kidney (CEK) cells after adapting to the chick embryo. To investigate the dynamic changes in IBV load in the supernatant of primary CEK cells, we developed an SYBR Green I-based real-time polymerase chain reaction assay to quantify nucleic copy numbers of the IBV-Sczy3 strain. The 20, 54, and 87th generations of CEK-adapted IBV-Sczy3 strains were used to infect CEK cells, and then nucleic copy numbers in the samples of supernatant collected at 12, 24, 36, 48, 60, and 72 h were detected. The results showed that the rapid growth period of the virus load of all the 3 generations was approximately 12-36 h post-infection; the peak of the virus load appeared at 36 h post-infection and then decreased gradually in the order of 20th > 54th > 87th for the 3 generations of CEK-adapted strains; the dynamic change curve of the IBV load in the supernatant of primary CEK cells showed a single peak. The results of this study provide a useful reference for CEK-adapted IBV field strains and the production of CEK-attenuated IBV vaccine.

[Relation between macrophages in peritoneal fluid of endometriosis and infertility]

Peritoneal fluid was collected from 18 endometriosis-associated infertile patients and 14 unexplained infertile women. The cells were counted in a hemacytometer and subjected to morphologic analysis. The phagocytic activity on Candida Albicans and on Sperms was evaluated and the activity of acid phosphatase in the pelvic fluid and within the macrophages were measured. The results showed that the endometriosis samples have macrophages of large size as compared with the macrophages found in unexplained infertile or fertile women, the concentration of pelvic macrophages in endometriosis is higher, the phagocytic and bactericidal activity is also higher and the macrophages in endometriosis engulf sperms as well. The accentuated activity of pelvic macrophages may be associated with the infertility in patients with endometriosis.