[Effect of inhibiting perivascular adhesion on intimal hyperplasia of the vein grafts in rabbits].

Objective: To investigate the effect of preventing perivascular adhesion with topical application of sodium hyaluronate on intimal hyperplasia of the vein grafts in rabbits. Methods: Twenty-four male New Zealand white rabbits, aged 5 months, were randomly divided into 2 groups: Group A and B (n=12 rabbits per group). Artery defect model was established by cutting about 1 cm artery from the middle part of the dissociated left common carotid artery. A section about 3 cm was cut from the right external jugular vein, and the harvested vein was inverted and end-to-end anastomosed to the artery defect. After anastomosis, the adventitia and two anastomosis of the grafted veins in group A was applied 0.2 ml sodium hyaluronate locally to, and corresponding site in Group B was served as a control, but with the sterile normal saline. The grafted veins were obtained 1, 2 and 4 weeks after operation, HE staining and Masson staining were preformed for histological changes of grafted vein wall, proliferating cell nuclear antigen (PCNA) and platelet-derived growth factor (PDGF) immunohistochemistry staining were conducted for proliferation and expression and distribution of PDGF of the grafted vein. Results: The macroscopic and histological observation showed that the perivascular adhesions in Group A were looser when compared with those in Group B. The thickness of the intima, the degree of intima hyperplasia of 2 groups at different time points were as follows: at 1 week after operation, group A[(25.5±3.9) µm, (1.2±0.1) ]and group B[(26.2±4.2)µm, (1.2±0.1)]; at 2 weeks after operation, group A[(44.3±2.5)µm, (1.2±0.1)]and group B[(51.0±3.8)µm, (1.4±0.0)]; at 4 weeks after operation, group A[(69.9±6.8)µm, (1.5±0.1)] and group B[(84.4±6.4)µm, (1.7±0.1)]. Group A was inferior to group B in terms of the above three parameters 2 and 4weeks after operation (P<0.05). Cell proliferation index of intima and that of media were as follows: at 1 week after operation, group A (7.4±2.2), (21.5±3.2) and group B (11.5±2.0), (28.6±4.5); at 2 weeks, group A (20.0±3.2), (35.8±3.4) and group B (26.8±4.1), ( 42.6±4.2); at 4 weeks, group A (11.4±2.0), (22.1±2.7) and group B (15.5±2.4, 28.6±3.9). Group A was inferior to group B in terms of cell proliferation index of intima and media 1, 2 and 4 weeks after operation (P<0.05). The percentage of PDGF-positive cells of intima, media and adventitia was as follows: at 1 week after operation, group A (7.7±1.6), (19.6±3.7), (2.5±1.5) and group B (7.6±2.4), (20.6±4.4), (10.3±2.3); at 2 weeks after operation, group A (11.4±2.6), (19.8±3.1), (12.9±3.3) and group B (19.5±3.5), ( 30.6±5.2), (30.5±5.8); at 4 weeks after operation, group A (6.2±1.9), ( 11.1±2.8), (10.2±2.4) and group B (10.5±2.0), (18.6±3.2), (26.5±3.8). Group A was inferior to group B in terms of the percentage of PDGF-positive cells of intima, media and adventitia 2 and 4 weeks after operation (P<0.05) and Group A was inferior to group B that of adventitia 1 week after operation (P<0.05). Conclusion: Preventing perivascular adhesion with topical application of sodium hyaluronate can inhibit intimal hyperplasia.

Evaluation of the semen swim-up method for bovine sperm RNA extraction.

Isolation of high-quality RNA is important for assessing sperm gene expression, and semen purification methods may affect the integrity of the isolated RNA. This study evaluated the effectiveness of the sperm swim-up method for seminal RNA isolation. Frozen semen samples in straws from three bulls of proven fertility were purified by the swim-up method. RNA extraction was carried out using the E.Z.N.A.(TM) Total RNA kit II, with non-swim-up sperm as a control. Total sperm RNA was analyzed by UV spectrophotometry, reverse transcription polymerase chain reaction (RT-PCR), and agarose gel electrophoresis, and expression of the sex-determining region on the Y chromosome (SRY), leptin (LEP), and ribosomal protein subunit 23 (RPS23) genes, were determined. 18S RNA was used as a positive control. Fewer somatic cells were found in sperm swim-up samples than in the non-swim-up counterparts (0 x 10(3) vs 17.33 ± 2.52 x 10(3) sperm, P < 0.05). In addition, high-quality RNA was obtained in about 2 h, with no significant difference between groups. Interestingly, the yields of RNA fragments containing ≥200 nucleotides were significantly reduced in sperm swim-up samples (0.92 ± 0.41 x 10(7) sperm) compared with the non-swim-up samples (1.36 ± 0.33 x 10(7) sperm, P < 0.05). After RT-PCR, clear bands representing SRY, LEP, and RPS23 in sperm cDNA were observed on agarose gel electrophoresis. Finally, no bands corresponding to 18S RNA were found in RNA samples from the sperm swim-up group. Our findings suggest that small amounts of sperm RNA can be efficiently extracted from frozen straw semen samples using the swim-up technique.

[Advances on the application of physical airway clearance techniques in the treatment of inhalation injury].

Although the treatment of patients with burns combined with inhalation injury has achieved great success, from the perspective of epidemiology, inhalation injury is still the most common cause of death in mass burns. Such patients often suffered burns of large total body surface area, which is difficult to treat, with airway management as one of the core links. Physical airway clearance technique (ACT) acts on a patient's respiratory system by physical means, to discharge secretions and foreign bodies in the airway, achieve airway clearance, and improve gas exchange. In addition, the technique can prevent or alleviate many complications, thereby improving the clinical outcome of patients with inhalation injury. This article reviews the application of physical ACT in the field of inhalation injury, and to provide decision-making basis for clinical medical staff to choose physical ACT corresponding to the patient's condition.

[Epidemiological characteristics and risk factors of sepsis development and death in patients with extremely severe burns].

Objective: To explore the epidemiological characteristics and risk factors of sepsis development and death in patients with extremely severe burns. Methods: A retrospective case series study was conducted. From January 2017 to December 2021, 135 patients with extremely severe burns who met the inclusion criteria were admitted to the Department of Burn and Wound Repair of the Second Affiliated Hospital of Zhejiang University School of Medicine, including 100 males and 35 females, aged 18-84 years. The incidence and diagnosis time of sepsis, the rate of positive microbial culture of blood samples (hereinafter referred to as positive blood culture), and the mortality rate of all patients, as well as the incidence of sepsis and the pathogen of infection in patients with positive blood culture were recorded (statistically analyzed with chi-square test or Fisher's exact probability test). According to the occurrence of sepsis, all patients were divided into sepsis group (58 cases) and non-sepsis group (77 cases), and the gender, age, body mass index, history of hypertension, history of diabetes, combination of inhalation injury, burn site, burn type, total burn area, and combined injury of patients were compared between the two groups. According to the outcome, all patients were divided into death group (37 cases) and survival group (98 cases), and the aforementioned data grouped according to sepsis as well as the stability of shock period and the combination of sepsis of patients were compared between the two groups. The aforementioned data between two groups were statistically analyzed with univariate analysis of independent sample t test, Wilcoxon rank-sum test, Mann-Whitney U test, chi-square test, or Fisher's exact probability test. Factors with P<0.1 were selected for multivariate logistic regression analysis to screen independent risk factors of sepsis and death in patients with extremely severe burns. Results: Among all patients, the incidence of sepsis was 42.96% (58/135), the diagnosis time of sepsis was 14 (7, 24) d after injury, the positive blood culture rate was 62.22% (84/135), and the mortality rate was 27.41% (37/135). The incidence of sepsis of patients with positive blood culture was 69.05% (58/84). The top 5 pathogenic bacteria in the detection rate of septic patients with positive blood culture were Acinetobacter baumannii, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, and Enterobacter cloacae, ranking from high to low, and the proportion of Acinetobacter baumannii infected was significantly higher than that of non-septic patients with positive blood culture (χ2=7.49, P<0.05). Compared with those in non-sepsis group, the proportion of combination of inhalation injury, the proportion of perineal burns, and the total burn area of patients in sepsis group increased significantly (with χ2 values of 11.08 and 17.47, respectively, Z=5.68, P<0.05), while the other indicators did not change significantly (P>0.05). Multivariate logistic regression analysis showed that combination of inhalation injury, total burn area ≥80% total body surface area (TBSA), and perineal burns were independent risk factors for patients with extremely severe burns developing sepsis (with odds ratios of 3.15, 7.24, and 3.24, respectively, with 95% confidence intervals of 1.07 to 9.29, 1.79 to 29.34, and 1.21 to 8.68, respectively, P<0.05). Compared with those in survival group, the proportion of combination of inhalation injury, the proportion of perineal burns, and the proportion of combination of sepsis (with χ2 values of 6.55, 11.64, and 22.26, respectively, P values all <0.05), total burn area (Z=4.25, P<0.05), and proportion of instability of shock period (P<0.05) of patients in death group all increased significantly, while the other indicators did not change significantly (P>0.05). Multivariate logistic regression analysis showed that the instability of shock period and combination of sepsis were independent risk factors for death of patients with extremely severe burns (with odds ratios of 4.87 and 3.45, respectively, with 95% confidence intervals of 1.21 to 19.57 and 1.28 to 9.33, respectively, P<0.05). Conclusions: Patients with extremely severe burns have a high incidence of sepsis and a high mortality rate. The peak period of sepsis onset is 2 weeks after injury, with Acinetobacter baumannii as the most prominent infectious pathogen. Combination of inhalation injury, total burn area ≥80% TBSA, and perineal burns are independent risk factors for extremely severe burn patients complicated with sepsis, and combination of sepsis and instability of shock period are independent risk factors for death of patients with extremely severe burns.

[Effects of three-dimensional bioprinting antibacterial hydrogel on full-thickness skin defect wounds in rats].

Objective: To explore the effects of three-dimensional (3D) bioprinting gelatin methacrylamide (GelMA) hydrogel loaded with nano silver on full-thickness skin defect wounds in rats. Methods: The experimental research method was adopted. The morphology, particle diameter, and distribution of silver nanoparticles in nano silver solution with different mass concentrations and the pore structure of silver-containing GelMA hydrogel with different final mass fractions of GelMA were observed by scanning electron microscope and the pore size was calculated. On treatment day 1, 3, 7, and 14, the concentration of nano silver released from the hydrogel containing GelMA with final mass fraction of 15% and nano silver with final mass concentration of 10 mg/L was detected by mass spectrometer. At 24 h of culture, the diameters of inhibition zone of GelMA hydrogel containing final mass concentration of 0 (no nano silver), 25, 50, and 100 mg/L nano silver against Staphylococcus aureus and Escherichia coli were detected. Fibroblasts (Fbs) and adipose stem cells (ASCs) were isolated respectively by enzymatic digestion using the discarded prepuce after circumcision from a 5-year-old healthy boy who was treated in the Department of Urology of the Second Affiliated Hospital of Zhejiang University School of Medicine in July 2020, and the discarded fat tissue after liposuction from a 23-year-old healthy woman who was treated in the Department of Plastic Surgery of the Hospital in July 2020. The Fbs were divided into blank control group (culture medium only), 2 mg/L nano sliver group, 5 mg/L nano sliver group, 10 mg/L nano sliver group, 25 mg/L nano sliver group, and 50 mg/L nano sliver group, which were added with the corresponding final mass concentrations of nano sliver solution, respectively. At 48 h of culture, the Fb proliferation viability was detected by cell counting kit 8 method. The Fbs were divided into 0 mg/L silver-containing GelMA hydrogel group, 10 mg/L silver-containing GelMA hydrogel group, 50 mg/L silver-containing GelMA hydrogel group, and 100 mg/L silver-containing GelMA hydrogel group and then were correspondingly treated. On culture day 1, 3, and 7, the Fb proliferation viability was detected as before. The ASCs were mixed into GelMA hydrogel and divided into 3D bioprinting group and non-printing group. On culture day 1, 3, and 7, the ASC proliferation viability was detected as before and cell growth was observed by live/dead cell fluorescence staining. The sample numbers in the above experiments were all 3. Four full-thickness skin defect wounds were produced on the back of 18 male Sprague-Dawley rats aged 4 to 6 weeks. The wounds were divided into hydrogel alone group, hydrogel/nano sliver group, hydrogel scaffold/nano sliver group, and hydrogel scaffold/nano sliver/ASC group, and transplanted with the corresponding scaffolds, respectively. On post injury day (PID) 4, 7, 14, and 21, the wound healing was observed and the wound healing rate was calculated (n=6). On PID 7 and 14, histopathological changes of wounds were observed by hematoxylin eosin staining (n=6). On PID 21, collagen deposition of wounds was observed by Masson staining (n=3). Data were statistically analyzed with one-way analysis of variance, analysis of variance for repeated measurement, Bonferroni correction, and independent sample t test. Results: The sliver nano particles in nano silver solution with different mass concentrations were all round, in scattered distribution and uniform in size. The silver-containing GelMA hydrogels with different final mass fractions of GelMA all showed pore structures of different sizes and interconnections. The pore size of silver-containing GelMA hydrogel with 10% final mass fraction was significantly larger than that of silver-containing GelMA hydrogels with 15% and 20% final mass fractions (with P values both below 0.05). On treatment day 1, 3, and 7, the concentration of nano silver released from silver-containing GelMA hydrogel in vitro showed a relatively flat trend. On treatment day 14, the concentration of released nano silver in vitro increased rapidly. At 24 h of culture, the diameters of inhibition zone of GelMA hydrogel containing 0, 25, 50, and 100 mg/L nano silver against Staphylococcus aureus and Escherichia coli were 0, 0, 0.7, and 2.1 mm and 0, 1.4, 3.2, and 3.3 mm, respectively. At 48 h of culture, the proliferation activity of Fbs in 2 mg/L nano silver group and 5 mg/L nano silver group was both significantly higher than that in blank control group (P<0.05), and the proliferation activity of Fbs in 10 mg/L nano silver group, 25 mg/L nano silver group, and 50 mg/L nano silver group was all significantly lower than that in blank control group (P<0.05). Compared with the that of Fbs in 0 mg/L silver-containing GelMA hydrogel group, the proliferation activity of Fbs in 50 mg/L silver-containing GelMA hydrogel group and 100 mg/L silver-containing GelMA hydrogel group was all significantly decreased on culture day 1 (P<0.05); the proliferation activity of Fbs in 50 mg/L silver-containing GelMA hydrogel group was significantly increased (P<0.05), while the proliferation activity of Fbs in 100 mg/L silver-containing GelMA hydrogel group was significantly decreased on culture day 3 (P<0.05); the proliferation activity of Fbs in 100 mg/L silver-containing GelMA hydrogel group was significantly decreased on culture day 7 (P<0.05). The proliferation activity of ASCs in 3D bioprinting group show no statistically significant differences to that in non-printing group on culture day 1 (P>0.05). The proliferation activity of ASCs in 3D bioprinting group was significantly higher than that in non-printing group on culture day 3 and 7 (with t values of 21.50 and 12.95, respectively, P<0.05). On culture day 1, the number of dead ASCs in 3D bioprinting group was slightly more than that in non-printing group. On culture day 3 and 5, the majority of ASCs in 3D bioprinting group and non-printing group were living cells. On PID 4, the wounds of rats in hydrogel alone group and hydrogel/nano sliver group had more exudation, and the wounds of rats in hydrogel scaffold/nano sliver group and hydrogel scaffold/nano sliver/ASC group were dry without obvious signs of infection. On PID 7, there was still a small amount of exudation on the wounds of rats in hydrogel alone group and hydrogel/nano sliver group, while the wounds of rats in hydrogel scaffold/nano sliver group and hydrogel scaffold/nano sliver/ASC group were dry and scabbed. On PID 14, the hydrogels on the wound surface of rats in the four groups all fell off. On PID 21, a small area of wounds remained unhealed in hydrogel alone group. On PID 4 and 7, the wound healing rates of rats in hydrogel scaffold/nano sliver/ASC group were significantly higher than those of the other three groups (P<0.05). On PID 14, the wound healing rate of rats in hydrogel scaffold/nano sliver/ASC group was significantly higher than the wound healing rates in hydrogel alone group and hydrogel/nano sliver group (all P<0.05). On PID 21, the wound healing rate of rats in hydrogel alone group was significantly lower than that in hydrogel scaffold/nano sliver/ASC group (P<0.05). On PID 7, the hydrogels on the wound surface of rats in the four groups remained in place; on PID 14, the hydrogel in hydrogel alone group was separated from the wounds of rats, while some hydrogels still existed in the new tissue of the wounds of rats in the other three groups. On PID 21, the collagen arrangement in the wounds of rats in hydrogel alone group was out of order, while the collagen arrangement in the wounds of rats in hydrogel/nano sliver group, and hydrogel scaffold/nano sliver/ASC group was relatively orderly. Conclusions: Silver-containing GelMA hydrogel has good biocompatibility and antibacterial properties. Its three-dimensional bioprinted double-layer structure can better integrate with new formed tissue in the full-thickness skin defect wounds in rats and promote wound healing.

[A brief discussion on precision nutrition support for severe burn patients from theory to practice].

Severe burns can lead to sustained hypermetabolism in the body, resulting in delayed wound healing, and malnutrition, dysfunction, and even death of patients. It is critical to carry out adequate nutritional risk assessment and provide individualized nutritional support to improve the prognosis of patients with severe burns. This paper describes and summarizes precision nutrition support for severe burn patients from theory to clinical practice.

[Research advances on biomaterials for the delivery of growth factors to regulate wound repair].

Wound repair is a highly coordinated and mutually regulated complex process involving various kinds of cells, extracellular matrices and cytokines. A variety of growth factors play an important regulatory role in wound healing, and it is critical to achieve effective delivery and sustained function of growth factors. In recent years, the application of biomaterials in tissue engineering has shown great potential, and the effective delivery of growth factors by biomaterials has attracted increasing attention. Based on this, this paper introduces the mechanism of related growth factors in the process of wound healing, focusing on the recent progress of biomaterial delivery of growth factors to accelerate wound healing, in order to provide new enlightenment for clinical wound treatment.

[Effect of sedation on resting energy expenditure in patients with extremely severe burns and the choice of energy estimation formula].

Objective: To investigate the effect of sedation on resting energy expenditure (REE) in patients with extremely severe burns and the choice of REE estimation formula during the treatment. Methods: A retrospective non-randomized controlled clinical study was conducted. From April 2020 to April 2022, 21 patients with extremely severe burns who met the inclusion criteria and underwent mechanical ventilation treatment were admitted to the Department of Burn and Wound Repair of Second Affiliated Hospital of Zhejiang University School of Medicine, including 16 males and 5 females, aged 60 (50, 69) years. Early anti-shock therapy, debridement, skin transplantation, nutritional support, and other conventional treatments were applied to all patients. Patients were sedated when they had obvious agitation or a tendency to extubate, which might lead to aggravation of the disease. REE measurement was performed on patients using indirect calorimetry on post-injury day 3, 5, 7, 9, 11, 14 and every 7 days thereafter until the patient died or being successfully weaned from ventilator. Totally 99 times of measurements were carried out, of which 58 times were measured in the sedated state of patients, and 41 times were measured in the non-sedated state of patients. The age, weight, body surface area, residual wound area, post-injury days of patients were recorded on the day when REE was measured (hereinafter briefly referred to as the measurement day). The REE on the measurement day was calculated with intensive care unit conventional REE estimation formula Thumb formula and special REE estimation formulas for burns including the Third Military Medical University formula, the Peng Xi team's linear formula, Hangang formula. The differences between the sedated state and the non-sedated state in the clinical materials, measured and formula calculated values of REE of patients on the measurement day were compared by Mann-Whitney U test and independent sample t test. The differences between the REE formula calculated values and the REE measured value (reflecting the overall consistency) in the sedated state were compared by Wilcoxon signed rank-sum test. The Bland-Altman method was used to assess the individual consistency between the REE formula calculated value and the REE measured value in the sedated state, and to calculate the proportion of the REE formula calculated value within the range of ±10% of the REE measured value (hereinafter referred to as the accuracy rate). Root mean square error (RMSE) was used to evaluate the accuracy of the REE formula calculated value relative to the REE measured value. Results: Compared with those in the non-sedated state, there was no statistically significant change in patient's age or post-injury days on the measurement day in the sedated state (P>0.05), but the weight was heavier (Z=-3.58, P<0.01), and both the body surface area and the residual wound area were larger (with Z values of -2.99 and -4.52, respectively, P<0.01). Between the sedated state and the non-sedated state, the REE measured values of patients were similar (P>0.05). Compared with those in the non-sedated state, the REE values of patients calculated by Thumb formula, the Third Military Medical University formula, the Peng Xi team's linear formula, and Hangang formula on the measurement day in the sedated state were significantly increased (with Z values of -3.58 and -5.70, t values of -3.58 and -2.74, respectively, P<0.01). In the sedated state, compared with the REE measured value, there were statistically significant changes in REE values of patients calculated by Thumb formula, the Third Military Medical University formula, and Hangang formula on the measurement day (with Z values of -2.13, -5.67, and -3.09, respectively, P<0.05 or P<0.01), while the REE value of patients calculated by the Peng Xi team's linear formula on the measurement day did not change significantly(P>0.05). The analysis of the Bland-Altman method showed that in the sedated state, compared with the REE measured value, the individual consistency of the calculated value of each formula was good; Thumb formula and Hangang formula significantly underestimated the patients' REE value (with the average value of the difference between the formula calculated value and the measured value of -1 463 and -1 717 kJ/d, the 95% confidence interval of -2 491 to -434 and -2 744 to -687 kJ/d, respectively), but the individual differences were small; the Third Military Medical University formula significantly overestimated the patients' REE value (with the average value of the difference between the formula calculated value and the measured value of 3 530 kJ/d, the 95% confidence interval of 2 521 to 4 539 kJ/d), but the individual difference was small; the Peng Xi team's linear formula did not significantly overestimate the patients' REE value (with the average value of the difference between the formula calculated value and the measured value of 294 kJ/d, the 95% confidence interval of -907 to 1 496 kJ/d), while the difference standard deviation was 4 568 kJ/d, which showed a large individual difference. In the sedated state, relative to the REE measured value, the accuracy rates of REE values calculated by Thumb formula, the Third Military Medical University formula, the Peng Xi team's linear formula, and Hangang formula were 25.9% (15/58), 15.5% (9/58), 10.3% (6/58), and 15.5% (9/58), respectively, and RMSE values were 4 143.6, 5 189.1, 4 538.6, and 4 239.8 kJ/d, respectively. Conclusions: Sedative therapy leads to a significant decrease in REE in patients with extremely severe burns undergoing mechanical ventilation treatment. When REE cannot be regularly monitored by indirect calorimetry to determine nutritional support regimens, patients with extremely severe burns undergoing sedation may be prioritized to estimate REE using Thumb formula.

[A case of chronic refractory wound in the abdomen caused by residual foreign body].

A 59-year-old male patient with local sinus tract formation due to residual foreign body was admitted to the Second Affiliated Hospital of Zhejiang University College of Medicine on December 17, 2018. The examination showed that the residual foreign body was the component of a sticky cloth implanted when the patient underwent appendectomy 27 years ago. Hypertrophic scar developed at the right-lower abdominal incision for appendectomy 23 years ago and the secondary infection after cicatrectomy resulted in non-healing of the wound. The chronic refractory wound healed completely after surgical treatment in our hospital after this admission. The postoperative pathological examination revealed local inflammatory granuloma. This case suggests that chronic refractory wound is likely to form when secondary infection occurs following the surgical procedure near the implant, and aggressive surgery is an effective way to solve this problem.

[Application effects of feedforward control theory in the rollover bed treatment of mass patients with burn-explosion combined injury].

Objective: To explore the application effects of feedforward control theory in the rollover bed treatment of mass patients with burn-explosion combined injury. Methods: A retrospective observational research was conducted. From June 13 to 14, 2020, 15 patients with severe burn-explosion combined injury caused by liquefied natural gas tank car explosion and conforming to the inclusion criteria were admitted to the Second Affiliated Hospital of Zhejiang University School of Medicine. There were 13 males and 2 females, aged 33-92 (66±17) years. All the patients were treated with rollover bed from 48 h post admission, and the feedforward control theory was introduced, including establishing a special feedforward control management team for rollover bed, clarifying the duties of the medical staff in the rollover bed treatment of patients, implementing the cooperation strategy of multidisciplinary physician, training and examining for 80 nurses in the temporarily organized nurse team in the form of "rollover bed workshop", and formulating the checklist and valuation list of rollover bed treatment for continuous quality control. The frequency and the total number of turning over, and successful rate of one-time posture change with the rollover bed of patients within 30 days of admission were recorded, the occurrences of adverse events caused by improper operation for the rollover bed during the treatment were observed, including respiratory and cardiac arrests, treatment interruption, unplanned extubation, bed falling, and skin graft displacement. The lowest levels of arterial partial pressure of oxygen (PaO2) and arterial partial pressure of carbon dioxide (PaCO2), the number of patients with oxygenation index>300 mmHg (1 mmHg=0.133 kPa), and the occurrence of acute respiratory distress syndrome (ARDS) of patients within 2 days of admission and on the 30th day of admission were recorded. Results: Within 30 days of admission, the patients were turned over with the rollover bed for 2 to 6 times each day, with a total of 1 320 turning over operations, the successful rate of one-time posture change reached 99.9% (1 319/1 320), and no adverse event occurred. Within 2 days of admission, the lowest levels of PaO2 and PaCO2 of the patients were (100±19) and (42±4) mmHg, respectively, and the number of patients with mild, moderate, and severe ARDS were 10, 2, and 3, respectively, and none of the patients had oxygenation index>300 mmHg. On the 30th day of admission, the lowest levels of PaO2 and PaCO2 of the patients were (135±28) and (37±8) mmHg, respectively, 3 patients developed moderate ARDS, 1 patient developed severe ARDS, and 11 patients had oxygenation index>300 mmHg. Conclusions: The introduction of feedforward control theory in the treatment of rollover bed of mass patients with burn-explosion combined injury can ensure safe and successful completion of turning over with the rollover bed, promote the repair of burn wound, and improve respiratory function, and therefore improve the treatment quality of patients.

Rapid detection of urinary tract infections using isotachophoresis and molecular beacons.

We present a novel assay for rapid detection and identification of bacterial urinary tract infections using isotachophoresis (ITP) and molecular beacons. We applied on-chip ITP to extract and focus 16S rRNA directly from bacterial lysate and used molecular beacons to achieve detection of bacteria specific sequences. We demonstrated detection of E. coli in bacteria cultures as well as in patient urine samples in the clinically relevant range 1E6-1E8 cfu/mL. For bacterial cultures we further demonstrate quantification in this range. The assay requires minimal sample preparation (a single centrifugation and dilution), and can be completed, from beginning of lysing to detection, in under 15 min. We believe that the principles presented here can be used for design of other rapid diagnostics or detection methods for pathogenic diseases.

[Interpretation of International Society for Burn Injury practice guidelines for burn care published in 2018].

The International Society of Burn Injury (ISBI) published the second part of the ISBI practice guidelines for burn care in 2018 in the journal of Burns. The main content of the guideline includes first aid for burns, topical drugs, burn infection, management of arteriovenous catheterization and metabolism, exercise and functional training, pain management, sedation, blood transfusion, deep venous thrombosis, mental disorder, and outpatient and discharge management. This article was written with the purpose to interpret the main points of the practice guidelines.

[Interpretation of International Society for Burn Injury practice guidelines for burn care published in 2016].

The care of burn patients varies obviously in different areas worldwide. In order to improve the level of burn care, the International Society for Burn Injury published the first part of practice guidelines for burn care in 2016 in the journal of Burns. This article was written with the purpose to interpret the main points of this part of the guidelines.

[Establishment of a predictive model for acute respiratory distress syndrome and analysis of its predictive value in critical burn patients].

Objective: To establish a predictive model for acute respiratory distress syndrome (ARDS) in critical burn patients with the screened independent risk factors, and to validate its predictive value. Methods: Totally 131 critical burn patients (101 males and 30 females, aged 18-84 years) who met the inclusion criteria were admitted to the Department of Burns of the Second Affiliated Hospital of Zhejiang University School of Medicine from January 2018 to December 2019. A retrospective case-control study was conducted. The patients were divided into ARDS group (54 cases) and non-ARDS group (77 cases) according to whether ARDS occurred or not. The statistics of patients in the two groups were recorded including the gender, age, burn index, combination of inhalation injury, smoking history, delayed resuscitation, indwelling nasogastric tube, and complication of sepsis, and the data were statistically analyzed with independent sample t test, chi-square test, and Fisher's exact probability test. The multivariate logistic regression analysis was performed on the indicators with statistically significant differences between the two groups to screen the independent risk factors for developing ARDS in critical burn patients, and the corresponding nomograph prediction model for the risk of ARDS in critical burn patients was established. The risk scores for patients developing ARDS were therefore obtained based on the above-mentioned nomograph, and the corresponding receiver operating characteristic (ROC) curve was drawn to calculate the area under the curve. The internal validation of the above-mentioned ARDS prediction model was performed using the Bootstrap method, and the area under the ROC curve was calculated for modeling group (79 cases) and validation group (52 cases), respectively. A calibration curve was drawn to assess the predictive conformity of the above-mentioned ARDS prediction model for the occurrence of ARDS in critical burn patients. Results: The burn index, proportion of combination of inhalation injury, and proportion of complication of sepsis of patients were significantly higher in ARDS group than in non-ARDS group (t=0.36, χ2=33.78, 49.92, P<0.01). The gender, age, smoking history, delayed resuscitation, and indwelling nasogastric tube of patients in ARDS group were close to those in non-ARDS group (P>0.05). The multivariate logistic regression analysis showed that the burn index, combination of inhalation injury, and complication of sepsis were the independent risk factors for developing ARDS in critical burn patients (odds ratio=1.05, 15.33, 5.02, 95% confidence interval=1.01-1.10, 2.65-88.42, 1.28-19.71, P<0.05 or P<0.01). The overall area under the ROC curve of the above-mentioned ARDS prediction model was 0.92 (95% confidence interval=0.88-0.97), and the area under the ROC curve was 0.95 and 0.91 (95% confidence interval=0.90-1.00, 0.86-0.97) for validation group and modeling group, respectively. When applying the above-mentioned ARDS prediction model for ARDS incidence prediction, there might be some risk of overestimating ARDS incidence when the prediction probability was <35.0% or >85.0%, and some risk of underestimating ARDS incidence when the prediction probability was 35.0%-85.0%. Conclusions: The burn index, inhalation injury, and sepsis are the independent risk factors for the occurrence of ARDS in critical burn patients. The risk prediction model for ARDS based on these three indicators has good predictive ability for ARDS in critical burn patients.

[Microbiological characteristics of patients with severe burns caused by blast and application of meta- genomics next-generation sequencing in the detection of pathogenic microorganisms].

Objective: To analyze the microbiological characteristics of patients with severe burns caused by blast in different periods and explore the application value of metagenomics next-generation sequencing (mNGS) in detecting pathogenic microorganisms. Methods: The retrospective observational study was applied. From June 13 to September 13, 2020, twenty-three patients (21 males and 2 females) with severe burns caused by blast who met the inclusion criteria were admitted to the Second Affiliated Hospital of Zhejiang University School of Medicine, with age of (64±5) years and total burn area of (86±14) % total body surface area. Abbreviated burn severity index (ABSI) score, revised Baux score, acute physiology and chronic health status evaluation (APACHE) Ⅱscore, and sequential organ failure assessment (SOFA) score were counted on admission. Within 7, 8-20 and 21-30 d after admission, the complications, infection source and distribution of pathogenic microorganisms in patients were recorded. The detection of pathogenic microorganisms was analyzed, and the difference in detection efficiency between microbial culture method and mNGS was compared. After admission, the infection of overall source distribution of pathogenic microorganisms in patients was analyzed, and the difference in detection efficiency between microbial culture method and mNGS was compared. Data were statistically analyzed with McNemar and Fisher exact probability test. Results: On admission, ABSI score, revised Baux score, APACHE Ⅱ score and SOFA score were (12.6±2.4), (91±22), (26±4), and (10.3±2.3) respectively. Within 7 d after admission, the main complications of patients were inhalation injury, septic shock, and hypoproteinemia. Patients were mainly infected with pathogenic microorganism on wound, blood stream, and lung. Within 8-20 d after admission, the incidence of septic shock was the highest. The incidence of inhalation injury was significantly lower than that of ≤7 d after admission (P<0.01), the main source of infection were wound, lung, and blood stream, and the incidence of wound and blood stream infection were significantly lower than that of ≤7 d after admission (P<0.01). Within 21-30 d after admission, the incidences of multiple organ failure and acute respiratory distress syndrome were low, the incidence of inhalation injury was significantly lower than that of ≤7 d after admission (P<0.01), and the incidence of septic shock was significantly lower than that of ≤7 d after admission (P<0.01) and 8-20 d after admission (P<0.01). There were only low bloodstream infections, and the incidence of wound infection was significantly lower than that of ≤7 d after admission (P<0.01) and 8-20 d after admission (P<0.05), and the incidences of lung and blood stream infection were significantly lower than those of ≤7 d after admission (P<0.01). Within ≤7 d after admission, gram-positive bacteria were mainly Staphylococcus aureus. Gram-negative bacteria were mainly Klebsiella pneumoniae and Stenotrophomonas maltophilia. The fungi contained only Candida. Within 8-20 d after admission, Staphylococcus aureus was mainly the gram-positive bacteria, and the detection rate of Enterococcus was significantly lower than that of ≤7 d after admission (P<0.01). Pseudomonas aeruginosa and Acinetobacter baumannii were the main gram-negative bacteria, and their detection rates were significantly lower than those of ≤7 d after admission (P<0.01).There was a new detection of Fusarium. Within 21-30 d after admission, Staphylococcus aureus was the mainly gram-positive bacteria, and the detection rates of Enterococcus and Bacillus were significantly lower than those of ≤7 d after admission (P<0.01). Pseudomonas aeruginosa and Acinetobacter baumannii were still the main gram-negative bacteria, and increased with the extension of time after admission. The detection rate of Pseudomonas aeruginosa was significantly higher than that of ≤7 d after admission (P<0.01) and 8-20 d after admission (P<0.01), and the detection rate of Acinetobacter baumannii was significantly higher than that of ≤7 d after admission (P<0.01). The detection rate of Klebsiella pneumoniae was significantly lower than those of ≤7 d after admission (P<0.01) and 8-20 d after admission (P<0.01). All Candida, Mould, Fusarium were detected. Within ≤7 d and 8-20 d, the consistency between mNGS and bacterial culture was high (κ=0.659, 0.596). Within 21-30 d after admission, the consistency between mNGS and bacterial culture was moderate (κ=0.407). In different time periods, the positive test rate of mNGS was basically constant, while that of microbial culture showed a decline with the extension time after admission. Five hundred and six strains of pathogenic microorganisms were isolated from wound, blood, sputum, and indwelling catheter, and Staphylococcus aureus, Pseudomonas aeruginosa, Acinetobacter baumannii, Klebsiella pneumoniae were the main pathogenic microorganisms. Pseudomonas aeruginosa and Acinetobacter baumannii were the most common in the wound samples, Klebsiella pneumoniae was more often seen in blood samples while Pseudomonas aeruginosa and Acinetobacter baumannii in sputum samples, and Acinetobacter baumannii in indwelling catheter samples were the most common. The detection rates of Pseudomonas aeruginosa in wound and sputum were significantly higher than those of blood (P<0.05 or P<0.01) and indwelling catheter (P<0.01), respectively. The consistency between the overall results of mNGS and microbial culture were moderate (κ=0.556). The consistency between mNGS and microbial culture was high in samples of blood and indwelling catheter (κ=0.631, 0.619), but those were moderate in sputum and wound (κ=0.558, 0.528). Conclusions: The most common infections of patients with severe burn caused by blast injury were wound infection and blood stream infection. With the extension of time after admission, the main pathogenic bacterial strains of patients changed from Staphylococcus aureus, Klebsiella pneumoniae, and Stenotrophomonas maltophilia to Acinetobacter baumannii and Pseudomonas aeruginosa. mNGS showed a higher positive rate of detecting pathogenic microorganisms than conventional microbial culture.

[The role of first-aid network construction in the early treatment of patients with critically severe hydrofluoric acid burns].

Objective: To explore the role of first-aid network construction in the early treatment of patients with critically severe hydrofluoric acid burns. Methods: Twenty-seven fluorine chemical enterprises distributed in Zhejiang province, Jiangxi Province, Fujian Province, and Inner Mongolia Autonomous Region and 22 hospitals with burn/plastic department or professional burn treatment group in Zhejiang province, including Zhejiang Quhua Hospital, and 5 hospitals outside Zhejiang province were involved in the first-aid network construction as member units. As the main unit, Zhejiang Quhua Hospital was responsible for the daily maintenance and technical guidance of the first-aid network. Zhejiang Quhua Hospital was assigned as the designated emergency hospital for 20 fluorine chemical enterprises, a near emergency hospital to the other 7 fluorine chemical enterprises was assigned as the designated hospital for them. Medical records of 56 patients (all males) with critically severe hydrofluoric acid burns who admitted to 5 first-aid network hospitals from January 2006 to June 2021, meeting the inclusion criteria, were involved in the retrospective cohort study. Based on whether the enterprise belonging to the first-aid network construction or not, the patients were divided into first-aid network group (27 cases, aged (41±9) years) and non first-aid network group (29 cases, aged (42±10) years). After the patients in the first-aid network group were injured, the enterprises and hospitals linked up immediately. The hospital where the patient was treated mobilize the treatment force, equipment, materials, and drugs in advance by the first-aid network, thereby realizing seamless joint between pre-hospital first-aid and in-hospital treatment. The hospital started the first-aid process and temporarily mobilized the rescue forces, equipment, materials, and drug after patients in non first-aid network group arrived at the department of emergency of the hospital. The time from injury to medical service, the first detection time of serum calcium, the time staying in department of emergency, the duration of hypocalcemia and hypomagnesemia, and the treatment outcome of patients in the two groups were recorded. Data were statistically analyzed with chi-square test, Fisher's exact probability test, independent-sample t test, and Wilcoxon rank-sum test. Results: The time from injury to medical service, the first detection time of serum calcium, and the time staying in department of emergency of patients in first-aid network group were 40.0 (30.0, 55.0), 23.0 (17.5, 37.5), and 42.0 (37.0, 53.0) min, which were significantly shorter than 180.0 (120.0, 240.0), 31.0 (22.5, 47.5), 61.0 (52.0, 65.5) min in non first-aid network group (Z=-6.17, -1.98, -4.15, P<0.05 or P<0.01). The duration of hypocalcemia and hypo- magnesemia of patients in first-aid network group were 1.2 (1.1, 1.6) and 1.9 (1.7, 2.1) h, which were significantly shorter than 4.6 (3.1, 6.2) and 3.2 (2.5, 4.6) h in non first-aid network group (Z=-5.80, -4.81, P<0.01). Three patients (11.1%) in first-aid network group died, among whom 2 patients died at 40 min after injury and 1 patient died 9.0 h after injury. Four patients (13.8%) died in non first-aid network group at 3.0, 3.0, 4.5, and 7.0 h after injury, respectively. The mortality rates of patients in the two groups were similar (P>0.05). Conclusions: Critically severe hydrofluoric acid burn is an extremely urgent situation encountered in clinical practice. The construction of a first-aid network creates condition for on-site treatment of patients and improves the first-aid efficiency, thereby gaining time to save lives.

Expression patterns and association analysis of the porcine DHX58 gene.

RIG-1 signalling is responsible for the detection of cytoplasmic viral RNA molecules. DEXH(Asp-Glu-X-His) box polypeptide 58 (encoded by DHX58) is a negative regulator of the RIG-1 signalling pathway. In human, the DHX58 gene can be upregulated and can inhibit the RIG-1 signalling pathway during viral infection. In this study, porcine DHX58 gene expression patterns were studied. According to our results, the porcine DHX58 gene was upregulated not only by the stimulation of Poly I:C but also by the stimulation of lipopolysaccharides (LPS). One polymorphism (g.4919G>C), detected in the ninth intron,was significantly associated with some blood parameters including the red cell distribution width of 1-day-old pigs and white blood cell counts, lymphocyte absolute counts, and platelet distribution width of 17-day-old pigs (P < 0.05). Moreover, the individuals with the genotype GG have a significantly higher mean white blood cell count than individuals with genotype CC or GC (P < 0.05). Our study indicates that DHX58 is an important gene that is associated with the immune response in swine.

[Practice of nosocomial infection management in burn department based on the American hospital evaluation standard of the Joint Commission International].

Objective: To explore the role of continuous quality improvement measures based on the American hospital evaluation standard of the Joint Commission International (JCI) in prevention and control of nosocomial infection in Burn Department of the Second Affiliated Hospital of Zhejiang University School of Medicine (hereinafter referred to as the author' s department). Methods: From 2013 to 2018, based on 11 JCI standards related to infection prevention and control and the current situation of the author' s department, more than 50 doctors, nurses, and nursing assistants from the author' s department participated in continuous improvement of the three-level management system of nosocomial infection in the author' s department, focusing on implementing of management of patient with multidrug resistant bacteria infection, optimizing the infection control management of instrument and cloth, and implementing target management on 5 indicators such as hand hygiene implementation rate, and carrying out inspection, quality management, and improvement on 11 items of prevention and control of nosocomial infection. The implementation rate of hand hygiene from 2013 to 2018 and the accuracy rate of hand hygiene from 2016 to 2018 of medical staff in the author' s department, and incidences of catheter-related bloodstream infection (CRBSI) of central venous, catheter-associated urinary tract infection (CAUTI), and ventilator associated pneumonia (VAP) of burn intensive care unit in the author's department from 2013 to 2018 were monitored.The following 7 indicators were monitored from 2013 to 2018, including false negative rate of nosocomial infection, incidence of hyperglycemia during intensive insulin treatment for severely burned patients, the implementation rate of CRBSI preventive measures, the specification rate of surface fixation of indwelling catheter, the implementation rate of VAP preventive measures, the accuracy rate of bed temperature during the use of suspended bed, and the implementation rate of hand hygiene of standardized training medical staff in the author' s department before and after improvement. Data were statistically analyzed with chi-square test. Results: The implementation rate of hand hygiene of medical staff in the author' s department was 88.0%-89.5% from 2013 to 2018, the correct rate of hand hygiene of medical staff in the author' s department was 95.10%-97.35%, and both reached the target values. The incidences of CRBSI in 2015, VAP in 2017, and CAUTI in 2013, 2014, and 2017 of burn intensive care unit failed to reach the respective target value and reached the respective target value after quality improvement, and the above-mentioned 3 indicators reached the respective target value in other years. From 2013 to 2018, the false negative rate of nosocomial infection and the incidence of hyperglycemia during intensive insulin treatment of severely burned patients in the author' s department after improvement were significantly lower than those before improvement (χ(2)=24.50, 4.74, P<0.05 or P<0.01), the implementation rate of CRBSI preventive measures, the specification rate of surface fixation of indwelling catheter, the implementation rate of VAP preventive measures, and the accuracy rate of bed temperature during the use of suspended bed after improvement in the author' s department were significantly higher than those before improvement (χ(2)=13.78, 6.50, 20.37, 13.92, P<0.05 or P<0.01), and the implementation rate of hand hygiene of standardized training medical staff in the author' s department after improvement was similar to that before improvement (χ(2)=1.71, P>0.05). Conclusions: The introduction of JCI standard can improve the implementation rate and accuracy rate of hand hygiene of medical staff in burn department, reduce the incidences of CRBSI, CAUTI, and VAP, and improve the effect of prevention and control of nosocomial infection in burn department.

[Teicoplanin-induced hypersensitivity syndrome in a diabetic foot patient with malignant ulcer].

A 58-year-old male patient with diabetic foot ulcer was admitted to the Second Affiliated Hospital of Zhejiang University School of Medicine on December 11, 2018. The patient was treated with local debridement, vacuum sealing drainage treatment, and dressing change and discharged after basic wound healing. On January 15, 2019, the patient was hospitalized again due to local infection and rupture of wound surface. He underwent a surgical debridement on the third day after second admission and was given intravenous infusion of 0.4 g teicoplanin twice daily. Histopathological examination after surgery showed keratinizing squamous-cell carcinoma. An extended squamous-cell carcinoma resection plus autologous split-thickness skin grafting and vacuum sealing drainage treatment was carried out on the 10th day after second admission. The patient's whole body turned red after surgery with rash, recurrent fever over 39 ℃, leucopenia, and thrombocytopenia. A multi-disciplinary consultation of physicians attributed these symptoms to teicoplanin-induced hypersensitivity syndrome. After withdrawal of teicoplanin and administration of hormone, the patient's temperature returned to normal, and the leucocyte count and platelet count recovered gradually. The patient was cured and discharged on the 49th day after second admission. The case presented reminds us of need to strictly follow the indications of teicoplanin prior to medication, be resolute to the administration and withdrawal, and be alert to adverse drug reactions when above-mentioned abnormalities occur, meanwhile, infection and rheumatic diseases are excluded.

[Nursing care of 29 central venous catheterizations for one burn patient with 99% total body surface area].

On February 6, 2017, one male patient aged 25 years with total burn area of 99% total body surface area (TBSA) and full-thickness burn area of 95% TBSA was transferred from a primary hospital to the Second Affiliated Hospital of Zhejiang University School of Medicine one day post injury. On admission, the patient was clearly conscious, with tracheotomy ventilator assisted ventilation, and received rehydration, antishock, anti-infection, nutritional support, debridement, skin grafting, and negative pressure treatment. During the hospitalization, the patient was in critical condition and 28 central venous catheterizations and 1 peripherally inserted central catheter were performed.Based on multidisciplinary cooperation and on the premise of full risk assessment, nurses focused on strengthening the nursing of central venous catheter related infection. The measures for central venous catheter care were improved after detection of carbapenems resistant Klebsiella pneumoniae from catheter tip attachment, wound exudate, and blood culture, active prevention measure targeted at thrombosis around central venous catheter was performed, and prevention of unplanned extubation was emphasized during the use of rotating bed, soaking bath, and agitation of patient. On the 171st day of admission, peripherally inserted central venous catheter was performed by intravenous therapy nurse specialist on the scar formation site of the right upper arm. The catheter was withdrawn after indwelling for 55 days and the patient recovered and was discharged. During follow-up of 18 months, the patient recovered well.