Rapid and accurate identification of bacteria utilizing laser-induced breakdown spectroscopy.

Timely and accurate identification of harmful bacterial species in the environment is paramount for preventing the spread of diseases and ensuring food safety. In this study, laser-induced breakdown spectroscopy technology was utilized, combined with four machine learning methods - KNN, PCA-KNN, RF, and SVM, to conduct classification and identification research on 7 different types of bacteria, adhering to various substrate materials. The experimental results showed that despite the nearly identical elemental composition of these bacteria, differences in the intensity of elemental spectral lines provide crucial information for identification of bacteria. Under conditions of high-purity aluminum substrate, the identification rates of the four modeling methods reached 74.91%, 84.05%, 85.36%, and 96.07%, respectively. In contrast, under graphite substrate conditions, the corresponding identification rates reached 96.87%, 98.11%, 98.93%, and 100%. Graphite is found to be more suitable as a substrate material for bacterial classification, attributed to the fact that more characteristic spectral lines are excited in bacteria under graphite substrate conditions. Additionally, the emission spectral lines of graphite itself are relatively scarce, resulting in less interference with other elemental spectral lines of bacteria. Meanwhile, SVM exhibited the highest precision rate and recall rate, reaching up to 1, making it the most effective classification method in this experiment. This study provides a valuable approach for the rapid and accurate identification of bacterial species based on LIBS, as well as substrate selection, enhancing efficient microbial identification capabilities in fields related to social security and military applications.

[Effect and mechanism of human adipose-derived stem cell exosomes on diabetic peripheral neuropathy].

Objective: To investigate the changes of artemin protein expression in diabetic peripheral neuropathy (DPN) and to explore the regulatory effect of human adipose-derived stem cell (ADSC) exosomes on the change of artemin protein expression. Methods: This research was a prospective observational clinical research combined with experimental research. Thirteen DPN patients (9 males and 4 females, aged 32 to 68 years) who were admitted to the First Affiliated Hospital of Air Force Medical University (hereinafter referred to as our hospital) from May 2022 to October 2023 and met the inclusion criteria were selected as DPN group, and 5 non-diabetes patients (4 males and 1 female, aged 29 to 61 years) who were admitted to our hospital in the same period of time and met the inclusion criteria were selected as control group. The toe nerve or sural nerve tissue in the abandoned tissue after debridement or amputation of patients in the two groups was collected. The pathological changes of nerve tissue were observed after hematoxylin-eosin staining; the protein expressions of S100ß and artemin in nerve tissue were observed after immunofluorescence staining, and the artemin protein expression was quantified; the protein and mRNA expressions of artemin were detected by Western blotting and real-time fluorescent quantitative reverse transcription polymerase chain reaction, respectively (the sample number in DPN group and control group was 13 and 5, respectively). Twelve male C57BL/6 mice aged 3 to 5 days were collected to isolate Schwann cells, and the cells were divided into conventional culture group cultured routinely, high glucose alone group (cultured with high concentration of glucose solution only), and high glucose+exosome group (cultured with high concentration of glucose solution and extracted human ADSC exosomes). After 24 hours of culture, the cell proliferation activity was detected by cell counting kit 8 (n=6). After 48 hours of culture, the protein expression of artemin was detected by Western blotting (n=3). Results: Compared with those in control group, the neural supporting cells decreased and the inflammatory cells increased in the nerve tissue of patients in DPN group, showing typical manifestations of nerve injury. Immunofluorescence staining showed that compared with those in control group, the nuclei was more, and the protein expression of S100ß was lower in nerve tissue of patients in DPN group. The protein expression of artemin in nerve tissue of patients in DPN group was 71±31, which was significantly lower than 1 729±62 in control group (t=76.92, P<0.05). Western blotting detection showed that the protein expression of artemin in nerve tissue of patients in DPN group was 0.74±0.08, which was significantly lower than 0.97±0.06 in control group (t=5.49, P<0.05). The artemin mRNA expression in nerve tissue of patients in DPN group was significantly lower than that in control group (t=7.65, P<0.05). After 24 hours of culture, compared with that in conventional culture group, the proliferation activities of Schwann cells in high glucose alone group and high glucose+exosome group were significantly decreased (P<0.05); compared with that in high glucose alone group, the proliferation activity of Schwann cells in high glucose+exosome group was significantly increased (P<0.05). After 48 hours of culture, compared with those in conventional culture group, the protein expressions of artemin of Schwann cells in high glucose alone group and high glucose+exosome group were significantly decreased (P<0.05); compared with that in high glucose alone group, the protein expression of artemin of Schwann cells in high glucose+exosome group was significantly increased (P<0.05). Conclusions: The protein expression of artemin in nerve tissue of DPN patients is lower than that in normal nerve tissue, which may be related to the reduction of proliferation activity of Schwann cells by high glucose. Human ADSC exosomes may improve the proliferation activity of Schwann cells by increasing artemin protein expression, thereby delaying the progression of DPN.

[Influences and mechanism of extracellular vesicles from dermal papilla cells of mice on human hypertrophic scar fibroblasts].

Objective: To investigate the influences and mechanism of extracellular vesicles from dermal papilla cells (DPC-EVs) of mice on human hypertrophic scar fibroblasts (HSFs). Methods: The study was an experimental research. The primary dermal papilla cells (DPCs) of whiskers were extracted from 10 6-week-old male C57BL/6J mice and identified successfully. The DPC-EVs were extracted from the 3rd to 5th passage DPCs by ultracentrifugation, and the morphology was observed through transmission electron microscope and the particle diameter was detected by nanoparticle tracking analyzer (n=3) at 24 h after culture. The 3rd passage of HSFs were divided into DPC-EV group and phosphate buffer solution (PBS) group, which were cultured with DPC-EVs and PBS, respectively. The cell scratch test was performed and cell migration rate at 24 h after scratching was calculated (n=5). The cell proliferation levels at 0 (after 12 h of starvation treatment and before adding DPC-EVs or PBS), 24, 48, 72, and 96 h after culture were detected by using cell counting kit 8 (n=4). The protein expressions of α-smooth muscle actin (α-SMA) and collagen typeⅠ (ColⅠ) in cells at 24 h after culture were detected by immunofluorescence method and Western blotting, and the protein expression of Krüppel-like factor 4 (KLF4) in cells at 24 h after culture was detected by Western blotting. After the 3rd passage of HSFs were cultured with DPC-EVs for 24 h, the cells were divided into blank control group, KLF4 knockdown group, and KLF4 overexpression group according to the random number table. The cells in blank control group were only routinely cultured for 48 h. The cells in KLF4 knockdown group and KLF4 overexpression group were incubated with KLF4 knockdown virus for 24 h, then the cells in KLF4 knockdown group were routinely cultured for 24 h while the cells in KLF4 overexpression group were incubated with KLF4 overexpression virus for 24 h. The protein expressions of KLF4, α-SMA, and ColⅠ in cells were detected by Western blotting at 48 h after culture. Results: At 24 h after culture, the extracted DPC-EVs showed vesicular structure with an average particle diameter of 108.8 nm. At 24 h after scratching, the migration rate of HSFs in PBS group was (54±10)%, which was significantly higher than (29±8)% in DPC-EV group (t=4.37, P<0.05). At 48, 72, and 96 h after culture, the proliferation levels of HSFs in DPC-EV group were significantly lower than those in PBS group (with t values of 4.06, 5.76, and 6.41, respectively, P<0.05). At 24 h after culture, the protein expressions of α-SMA and ColⅠ of HSFs in DPC-EV group were significantly lower than those in PBS group, while the protein expression of KLF4 was significantly higher than that in PBS group. At 48 h after culture, compared with those in blank control group, the protein expression of KLF4 of HSFs in KLF4 knockdown group was down-regulated, while the protein expressions of α-SMA and ColⅠ were both up-regulated; compared with those in KLF4 knockdown group, the protein expression of KLF4 of HSFs in KLF4 overexpression group was up-regulated, while the protein expressions of ColⅠ and α-SMA were down-regulated. Conclusions: The DPC-EVs of mice can inhibit the proliferation and migration of human HSFs and significantly inhibit the expressions of fibrosis markers α-SMA and ColⅠ in human HSFs by activating KLF4.

[Perioperative management of wounds associated with secondary sternal osteomyelitis and/or mediastinitis after sternotomy and its clinical effects].

Objective: To investigate the perioperative management of wounds associated with secondary sternal osteomyelitis and/or mediastinitis after sternotomy, and to evaluate its clinical effects. Methods: This study was a retrospective observational study. From January 2017 to December 2022, 36 patients with wounds associated with secondary sternal osteomyelitis and/or mediastinitis after sternotomy who were conformed to the inclusion criteria were admitted to the Burn Center of PLA of the First Affiliated Hospital of Air Force Medical University, including 23 males and 13 females, aged 25 to 81 years. Preparation for surgery was made. For patients with suspected retrosternal mediastinal abscess cavity, all cancellous bone of the unhealed sternum was bitten off to fully expose the retrosternal mediastinum, remove the source of infection and granulation tissue, and to fill the sternum defect with flipped unilateral pectoralis major muscle. For patients who had no retrosternal mediastinal infection but had fresh granulation tissue in unhealed sternal wounds, the necrotic tissue and a small amount of necrotic sternum were palliatively removed, and bilateral pectoralis major muscles were advanced and abutted to cover the sternal defect. After the skin in the donor area was closed by tension-relieving suture, continuous vacuum sealing drainage was performed, and continuous even infusion and lavage were added 24 hours later. The thorax was fixed with an armor-like chest strap, the patients were guided to breathe abdominally, with both upper limbs fixed to the lateral chest wall using a surgical restraint strap. The bacterial culture results of wound exudation specimens on admission were recorded. The wound condition observed during operation, debridement method, muscle flap covering method, intraoperative bleeding volume, days of postoperative infusion and lavage, lavage solution volume and changes on each day, and postoperative complications and wound healing time were recorded. After discharge, the wound healing quality, thorax shape, and mobility functions of thorax and both upper limbs were evaluated during follow-up. The stability and closure of sternum were observed by computed tomography (CT) reexamination. Results: On admission, among 36 patients, 33 cases were positive and 3 cases were negative in bacterial culture results of wound exudation specimens. Intraoperative observation showed that 26 patients had no retrosternal mediastinal infection but had fresh granulation tissue in unhealed sternal wounds, palliative debridement was performed and bilateral pectoralis major muscles were advanced and abutted to cover the defect. In 10 patients with suspected retrosternal mediastinal abscess cavity, the local sternum was completely removed by bite and the defect was covered using flipped unilateral pectoralis major muscle. During the operation, one patient experienced an innominate vein rupture and bleeding of approximately 3 000 mL during mediastinal exploration, and the remaining patients experienced bleeding of 100-1 000 mL. Postoperative infusion and lavage were performed for 4-7 days, with a lavage solution volume of 3 500-4 500 mL/d. The lavage solution gradually changed from dark red to light red and finally clear. Except for 1 patient who had suture rupture caused by lifting the patient under the armpit during nursing on the 3rd day after surgery, the wounds of the other patients healed smoothly after surgery, and the wound healing time of all patients was 7-21 days. Follow-up for 3 to 9 months after discharge showed that the patient who had suture rupture caused by armpit lifting died due to multiple organ failure. In 1 patient, the armor-like chest strap was removed 2 weeks after surgery, and the shoulder joint movement was not restricted, resulting in local rupture of the suture, which healed after dressing change. The wounds of the remaining patients healed well, and they resumed their daily life. The local skin of patient's pectoralis major muscle defect was slightly sunken and lower than that of the contralateral thorax in the patients undergoing treatment of pectoralis major muscle inversion, while no obvious thoracic deformity was observed in patients undergoing treatment with pectoralis major muscle propulsion and abutment. The chest and upper limb movement in all patients were slightly limited or normal. CT reexamination results of 10 patients showed that the sternum was stable, the local sternum was closed or covered completely with no lacuna or defects. Conclusions: Once the wound associated with secondary sternal osteomyelitis and/or mediastinitis after sternotomy is formed, individualized and precise debridement should be performed as soon as possible, different transfer ways of pectoralis major muscle flap should be chosen to cover the defect, and postoperative continuous infusion and lavage together with strict thorax and shoulder joint restraint and immobilization should be performed. This treatment strategy can ensure good wound healing without affecting the shape and function of the donor area.

[Research advances on the role of Schwann cells in diabetic peripheral neuropathy].

Diabetic peripheral neuropathy (DPN) is one of the common chronic complications of diabetes, resulting in neuropathy of spinal nerve, cranial nerve, and vegetative nerve. Diabetic distal symmetric multiple neuropathy is the most representative lesion of DPN, including symptoms of bilateral limbs pain, numbness, and paresthesia, etc. DPN is one of the main reasons causing diabetic foot ulcer (DFU). Schwann cells (SCs) are the primary glia cells of the peripheral nervous system, which play very important role in repairing after nerve injury. As the target cells of chronic hyperglycemia, SCs' functions, including the formation of myelin sheath, the secretion of neurotrophic factors, energy supplying for the axon, and the guidance of axon regeneration, etc., are damaged under the action of high glucose. The destroyed functions of SCs can inhibit the repair of damaged nerves and accelerate the progress of DPN. Therefore, if the damage of high glucose to SCs can be effectively reduced, it will provide a new way for the treatment of DPN and DFU and reduce the morbidity of DFU. This review focuses on the function of SCs and its relationship with DPN.

[Clinical effects of autologous split-thickness skin grafting for prefabricating urethra combined with scrotal flap in repairing middle urethral defect with penile defect].

Objective: To investigate the clinical effects of autologous split-thickness skin grafting for prefabricating urethra combined with scrotal flap in repairing middle urethral defect with penile defect. Methods: The retrospective observational study was conducted. Eight male patients (aged 14 to 58 years) with middle urethral defect and penile defect caused by various injuries who met the inclusion criteria were admitted to the First Affiliated Hospital of Air Force Medical University from January 2015 to January 2022. The length of urethral defect was 3 to 5 cm, and the wound area of penile defect after debridement was 5.0 cm×2.5 cm to 7.0 cm×5.5 cm. All the patients underwent autologous split-thickness skin grafting for prefabricating defect urethra in stage Ⅰ, and urethral anastomosis was performed and unilateral scrotal flap was transferred to reconstruct urethra and penis in stage Ⅱ. The area of scrotal flap was 6.0 cm×3.0 cm to 8.0 cm×6.0 cm. The wound in the donor area of skin graft was covered by oil gauze, and the wound of flap donor area was sutured directly. On the 7th day after the operation of stage Ⅱ, the survival of the flap was observed. In 3 weeks after the operation of stage Ⅱ, the urinary flow rate was measured by the urinary flow rate detector (urinary flow rate >15 mL/s was regarded as unobstructed urination), the urinary fistula and erectile function were observed, and the self-made therapeutic satisfaction questionnaire was used to investigate the therapeutic satisfaction degree of patients. During follow-up, the appearance of the flap recipient area was observed, the Vancouver scar scale (VSS) was used to evaluate the scar situation in the donor areas of skin graft and flap, the urinary flow rate was detected as before, the urethral stricture, urinary fistula, and erectile function were observed, and the therapeutic satisfaction degree of patients was investigated. Results: On the 7th day after the operation of stage Ⅱ, the flaps survived completely in 8 patients. In 3 weeks after the operation of stage Ⅱ, the urinary flow rate was 25.3 (18.0, 38.5) mL/s, with unobstructed urination, without urinary fistula and with erectile function, and the score of therapeutic satisfaction degree was 14.3 (14.0, 15.0). During follow-up of 1 to 7 years, the flap recipient area of 8 patients was full in appearance and not swollen, with similar color to the surrounding tissue; the VSS scores of the donor areas of skin graft and flap were 11.5 (10.0, 13.0) and 10.5 (9.3, 12.0), respectively, the urinary flow rate was 24.6 (17.7, 34.1) mL/s, with no urethral stricture, urinary fistula, and erectile dysfunction, and the score of therapeutic satisfaction degree was 13.5 (13.3, 14.8). Conclusions: Autologous split-thickness skin grafting for prefabricating urethra combined with scrotal flap in repairing the urethral and penile defects not only reconstructs the structure of urethra and the shape of penis, but also restores the sensation and erectile function of penis, with few postoperative complications, no obvious scar hyperplasia, and high satisfaction degree of patients, which is worthy of clinical promotion.

[Investigation of a carbon monoxide poisoning accident with a hidden source].

In June 2022, a carbon monoxide poisoning accident with hidden source occurred in a bonded gold/silver wire manufacturing enterprise in Guangzhou, causing 10 people to be poisoned, of which 1 was caused by carbon monoxide poisoning and 9 by carbon monoxide contact reaction. The symptoms were dizziness, fatigue and vomiting. After 5 to 7 h, the saturation of carboxyhemoglobin in finger pulse was 4% to 10%, and the saturation of carboxyhemoglobin in blood gas biochemical analysis was 1.9% to 5.8%. The concentration of carbon monoxide detected in the carbon borne purification plant of the enterprise was 34.46-37.26 mg/m(3). It was judged that the accident was carbon monoxide poisoning caused by carbon monoxide gas being transported to the work post along the gas transmission pipeline due to abnormal operation of the carbon borne purification plant. By investigating the source and cause of poison, this paper provides a warning for the similar process to prevent similar events, and provides a new idea for the identification of chemical poisoning risk. At the same time, it is warned that similar enterprises should fully consider the risk of poisoning under specific circumstances, strengthen equipment maintenance and repair, and prevent the occurrence of similar incidents.

[Paradoxical worsening after treatment of choroidal tuberculoma: a case report].

A young woman who complained of visual acuity decreased in the right eye for 12 days visited the Department of Ophthalmology. A solitary and occupancy lesion was seen in the posterior pole of the fundus of the patient's right eye, accompanied by intracranial and pulmonary tuberculosis. The diagnosis was choroidal tuberculoma, intracranial tuberculoma, and invasive pulmonary tuberculosis. After anti-tuberculosis treatment, the lesions of lung were better, but the lesions in the right eye and brain were paradoxical worsening. Finally, the lesion was calcification and absorption after combined glucocorticoid therapy.

[Intravenous infusion of methylene blue to visualize the ureter in laparoscopic colorectal surgery].

Objective: Intraoperative localization of the ureter can contribute to accurate dissection and minimize ureteral injury in colorectal surgery. We aim to summarize a single center's experience of fluorescence ureteral visualization using methylene blue (MB) and explore its visualization efficiency. Methods: This is a descriptive case-series-study. Clinical data of patients who had undergone laparoscopic colorectal surgery and fluorescence visualization of the ureter in the Gastrointestinal Surgery Department of Guangdong Provincial People's Hospital from March 2022 to May 2022 were retrospectively collected. Patients with incomplete surgery videos, renal insufficiency, or allergic reactions were excluded. MB was infused with 0.9% NaCl at 1.0 mg/kg in 100 mL of normal saline for 5 to 15 minutes during laparoscopic exploration. Imaging was performed using a device developed in-house by OptoMedic (Guangdong, China) that operates at 660nm to achieve excitation of MB. Clinical information, MB dosage, rate of successful fluorescence, time to fluorescence, operation time, blood loss, intraoperative blood oxygen levels, pathological staging, changes in renal function, and post-operative complications were retrospectively analyzed. Results: The study cohort comprised 27 patients (24 men and 3 women) with an average age of (60.25±16.95) years and an average body mass index of (21.72±3.42) kg/m2. The dosage of MB was 0.3-1.0 mg/kg and the infusion time was 5-15 minutes. Fluorescence signals were detected in all patients. The median time to signal detection was 20 (range, 10 to 40) minutes after MB infusion. The range of intraoperative blood oxygen fluctuation averaged 2.5% (range, 0 to 7.0%). The median change in creatine concentration was -1.3 (range, -17.2 to 29.2) µmol/L. No patients had complications associated with use of MB. Fluorescence visualization of the ureter was very valuable clinically in two patients (thick mesentery, stage T4). Conclusion: MB is a safe and effective means of visualizing the ureter by fluorescence during laparoscopic colorectal surgery, especially when the procedure is difficult. MB in a dosage of less than 1 mg/kg can slowly infused for more than 5 minutes during laparoscopic exploration. During the infusion, attention must be paid to blood oxygen fluctuations.

[A prospective randomized controlled study on the repair of skin and soft tissue defect in functional areas of children with full-thickness skin grafts from different sites of abdomen].

Objective: To compare and analyze the effect of repairing small skin and soft tissue defect wounds in functional areas of children with full-thickness skin grafts from different sites of abdomen. Methods: A prospective randomized controlled study was conducted. From January 2019 to June 2020, 60 female children with small skin and soft tissue defects in functional areas requiring full-thickness skin grafting, who met the inclusion criteria, were admitted to the First Affiliated Hospital of Air Force Medical University. According to the random number table, the children were divided into two groups, with 28 cases left in lateral abdomen group aged 5 (3, 8) years and 29 cases in lower abdomen group aged 5 (3, 7) years after the exclusion of several dropped-out children in follow-up. In lower abdomen group, 20 (12, 26) cm2 wounds of children were repaired with (24±10) cm2 full-thickness skin graft from transverse skin lines in the inferior abdomen area, while in lateral abdomen group, 23 (16, 32) cm2 wounds of children were repaired with (24±9) cm2 full-thickness skin graft from below the umbilical plane to above the groin in the lateral abdomen area. All the children were treated with continuous intradermal suture at the donor site incision and received continuous negative pressure treatment of -10.64 to -6.65 kPa in the donor and recipient areas after operation. The donor site was treated with a medical skin tension-reducing closure device since post-surgery day (PSD) 7. The use of medical skin tension-reducing closure device at the donor site, postoperative complications and suture removal time of the donor area were recorded, and the incidence of complications was calculated. On PSD 7, a self-designed efficacy satisfaction questionnaire was used to investigate the parents' satisfaction with the curative effect of their children. In post-surgery month (PSM) 1 and 6, Vancouver scar scale (VSS) was used to evaluate the scar at the donor site, and the VSS score difference between the two time points was calculated; the scar width at the donor site was measured with a ruler, and the scar width difference between the two time points was calculated. Data were statistically analyzed with independent sample t test or Cochran & Cox approximate t test, Mann-Whitney U test, and Fisher's exact probability test. Results: The proportion of children in lateral abdomen group who used the medical skin tension-reducing closure device in the donor area for equal to or more than 4 weeks after surgery was significantly higher than that in lower abdomen group (P<0.05). On PSD 7, there was one case of partial incision dehiscence in the donor area, one case of peripheral skin redness and swelling in the donor area, and one case of fat liquefaction in the donor area in lateral abdomen group, and one case of partial incision dehiscence in the donor area in lower abdomen group. The incidence of postoperative complications at the donor site of children in lower abdomen group was significantly lower than that in lateral abdomen group (P<0.05). Compared with that in lateral abdomen group, the suture removal time at the donor site of children after surgery in lower abdomen group was significantly shorter (t'=17.23, P<0.01). On PSD 7, the satisfaction score of parents with the curative effect of their children in lower abdomen group was significantly higher than that in lateral abdomen group (t'=20.14, P<0.01). In PSM 1 and 6, the VSS scores of scar at the donor site of children in lower abdomen group were 2.7±0.9 and 2.8±1.0, respectively, which were significantly lower than 7.1±2.2 and 9.1±2.7 in lateral abdomen group (with t values of 10.00 and 11.15, respectively, P<0.01). In PSM 6, the VSS score of scar at the donor site of children in lateral abdomen group was significantly higher than that in PSM 1 (t=3.10, P<0.01), while the VSS score of scar at the donor site of children in lower abdomen group was not significantly higher than that in PSM 1 (P>0.05). The VSS score difference of scar at the donor site of children in lateral abdomen group was significantly greater than that in lower abdomen group (Z=-8.12, P<0.01). In PSM 1 and 6, the scar widths at the donor site of children in lower abdomen group were 2.0 (1.0, 2.0) and 2.0 (2.0, 3.0) mm, respectively, which were significantly narrower than 6.0 (4.0, 10.0) and 8.5 (5.0, 12.0) mm in lateral abdomen group (with Z values of -13.41 and -14.70, respectively, P<0.01). In PSM 6, the scar width at the donor site of children in lateral abdomen group was significantly wider than that in PSM 1 (Z=-2.79, P<0.01), while the scar width at the donor site of children in lower abdomen group was not significantly wider than that in PSM 1 (P>0.05). The difference of scar width at the donor site of children in lateral abdomen group was significantly greater than that in lower abdomen group (Z=-14.93, P<0.01). Conclusions: The use of full-thickness skin grafts from the lower abdomen to repair small skin and soft tissue defect wounds in functional areas of children, especially girls, is effective, simple and easy to operate, and conforms to the principle of aesthetic repair. Compared with transplantation with full-thickness skin graft from the lateral abdomen, lower abdominal full-thickness skin grafting has a low incidence of donor site complications and no obvious scar hyperplasia, which is worthy of clinical promotion.

[Immune-related genes and their determined immune cell microenvironment to predict the prognosis of gastric adenocarcinoma].

Objective: Through bioinformatics analysis to screen key immune-related genes (IRGs) and cancer-related pathways in gastric adenocarcinoma (GAC) therapy, combining immune cell microenvironment to predict the prognosis of GAC. Methods: RNA sequencing and clinical data were obtained from public databases. Differentially expressed IRGs between GAC and normal tissues were identified by integrated bioinformatics analysis. Univariate and multivariate Cox regression analyses were applied to screen survival-associated IRGs. Then, we established the risk signature model and found another database for external validation. In addition, we explored the relationship with the immune cell microenvironment in each GAC sample using CIBERSORT algorithms. Results: A total of 78 differentially expressed IRGs were screened, including 47 up-regulated and 31 down-regulated genes. Subsequently, a five-IRGs signature (BMP8A、MMP12、NRG4、S100A9 and TUBB3) was significantly associated with the overall survival of GAC patients. Survival analysis indicated that patients in the high-risk group have a poor prognosis. The results of the multivariate analysis revealed that the risk score was an independent prognostic factor. Further analysis showed that the prognostic model had excellent predictive performance in both TCGA and GEO validated cohorts. Besides, the results of tumor-infiltrating immune cell analysis indicated that the risk score could reflect the status of the tumor immune microenvironment. Conclusion: BMP8A, MMP12, NRG4, S100A9 and TUBB3 with the risk signature model are associated with prognosis in patients with GAC, combined with tumor-infiltrating immune cells to provide new markers for immunotherapy in GAC.

[Epidemiological characteristics of local outbreak of COVID-19 caused by SARS-CoV-2 Delta variant in Liwan district, Guangzhou].

Objective: To analyze the epidemiological characteristics of a local outbreak of COVID-19 caused by SARS-CoV-2 B.1.617.2(Delta) variant in Liwan district, Guangzhou, and provide evidence for the further prevention and control of the Delta variant of COVID-19. Methods: From May 21 to June 18, 2021, the incidence data of COVID-19 caused by Delta variant were obtained from National Notifiable Disease Report System of Chinese Disease Prevention and Control Information System and Liwan District Center for Disease Control and Prevention of Guangzhou.Frequency analysis (proportions), histograms, and percentage stacked area plots were used to describe the epidemiological characteristics of the outbreaks. The incubation period and time-varying reproduction numbers (Rt) estimations were used for the further analysis. Results: By June 18, 2021, a total of 127 COVID-19 cases caused by Delta variant was reported in Liwan district. The youngest case was aged 2 years and the oldest was aged 85 years. There were 18.9% (24/127) aged <18 years, 43.3% (55/127) aged 18-59 years, and 37.8% (48/127) aged ≥60 years, the male to female ratio of the cases was 1∶1.35 (54∶73). The cases were mainly retired people (32.3%, 41/127), the jobless or unemployed (18.1%, 23/127), and students (16.5%, 21/127). The infections mainly occurred in Baihedong (70.1%, 89/127) and Zhongnan street (23.6%, 30/127) communities in the southern area of Liwan district. The median incubation period of the Delta variant infection was 6 days (range: 1-15 days). The clinical classification were mainly common type (64.6%, 82/127). The basic reproduction number (R0) was 5.1, Rt which once increased to 7.3. The transmissions mainly occurred in confined spaces, such as home (26.8%), restaurant (29.1%), neighborhood (3.9%), and market (3.1%), the household clustering was predominant. Close contacts tracing (66.1%) and community screening (33.1%) were the main ways to find the infections. Conclusion: The COVID-19 outbreak caused by Delta variant in Liwan district of Guangzhou was highly contagious, with the obvious characteristics of household clustering and high proportions of cases in adults aged 18-59 years and elderly people aged ≥60 years.

[Clinical effects of bridge-type continuous negative pressure suction in postoperative fixation of upper limb soft tissue defect wound repaired with pedicled abdominal flap].

Objective: To observe the clinical effects of bridge-type continuous negative pressure suction in postoperative fixation of upper limb soft tissue defect wound repaired with pedicled abdominal flap. Methods: The retrospective observational study was conducted. From April 2018 to October 2020, ninety-five patients who met the inclusion criteria were admitted to the First Affiliated Hospital of Air Force Medical University, including 55 males and 40 females, aged 5-78 years, with a defect wound area of 82 (9, 216) cm2. All patients underwent abdominal flap repair for soft tissue defects of hand and forearm. According to the different fixation methods adopted in the operation area, the patients were divided into negative pressure group (n=48) and plaster group (n=47). Wounds of the injury sites of patients in the 2 groups were repaired by flap transplantation after debridement. The negative pressure suction device was placed after dry gauze dressing to form a "bridge" to fix the affected upper limb and chest and abdomen in negative pressure group. Patients in plaster group were treated with conventional dry gauze matting and plaster fixation. On post surgery day (PSD) 1, 3, 5, 7, and 14, flap blood circulation and pain intensity of patients in the 2 groups were calculated by self-made blood flow scoring scale and Changhai Pain Ruler, respectively. On PSD 5, the common complications in operative area and surrounding skin were observed and their incidences were calculated. On PSD 7, satisfaction degree of patients was scored. During follow-up of one month after pedicle division, the appearance and functional recovery of the affected limb were observed. Data were statistically analyzed with analysis of variance for repeated measurement, independent samples t est, Cochran & Cox approximate t test, chi-square test, and Wilcoxon rank-sum test. Results: On PSD 1, 3, 5, 7, and 14, the flap blood circulation scores of patients in negative pressure group did not change significantly, while that of patients in plaster group showed a time-dependent decrease, and the flap blood circulation scores of patients in negative pressure group were significantly higher than those in plaster group (t=2.259, 2.552, 2.784, 2.821, 3.003, P<0.05 or P<0.01). There were no significant changes in the pain intensity scores of patients in negative pressure group, while those of patients in plaster group increased in a time-dependent manner, and the pain intensity scores of patients in negative pressure group were significantly lower than those in plaster group (t=-4.818, -4.944, -5.011, -5.976, -6.721, P<0.05). On PSD 5, the incidences of common complications in operative area and surrounding skin of patients in negative pressure group were significantly lower than those in plaster group (χ2=6.773, 5.269, P<0.05 or P<0.01). On PSD 7, the satisfaction score of patients in negative pressure group was 14.7±1.1, which was significantly higher than 7.4±1.8 in plaster group (t=23.934, P<0.01). During follow-up of one month after pedicle division, the appearance and function of the affected limb of patients in the 2 groups recovered well. Conclusions: After repairing the upper limb soft tissue defect wound with pedicled abdominal flap, the bridge-type continuous negative-pressure suction fixation can effectively immobilize the affected limbs, chest and abdomen, reduce the incidence of common complications in the operative area and surrounding skin, relieve the pain of immobilization of patients, improve the blood circulation of flap and patient's satisfaction. Thus, it is an effective, portable, comfortable, and easy-to-operate method.

[Clinical application effect of latissimus dorsi muscle flap in reconstruction of muscle strength around shoulder after electric burns].

Objective: To investigate the clinical application effect of latissimus dorsi muscle flap in reconstruction of muscle strength around shoulder after electric burns. Methods: From March 2014 to September 2020, 13 patients with electric burns and severe injury around shoulder were admitted to the First Affiliated Hospital of Air Force Medical University, including 11 males and 2 females, aged 19-55 years. A retrospective observational study was conducted. The left upper limbs were injured in 8 cases, and the right upper limbs were injured in 5 cases, all with eschar wounds of Ⅲ-Ⅳ degree. Among which, there were biceps defects in 6 cases, deltoid defects in 3 cases, triceps defects in 2 cases, and composite defects of multiple muscles around shoulder in 2 cases. The surgery was carried out in two stages. In stage Ⅰ, debridement and exploration of electric burn wounds around shoulders were conducted to preserve local tissue and save the limb as much as possible on the premise of guaranteeing the stability of the body condition. After the last debridement, the wound area was from 10 cm×6 cm to 40 cm×15 cm, the muscle defect area was from 8 cm×4 cm to 19 cm×12 cm, and the humerus was exposed in 7 patients. In stage Ⅱ, according to the residual limb defect degree, muscle reconstruction around shoulder was conducted with the latissimus dorsi muscle flap, and area of the latissimus dorsi muscle flap was 15 cm×6 cm to 20 cm×18 cm. The residual wounds were repaired with autologous split-thickness skin grafts of head, and the donor sites of muscle flaps were sutured directly. The survivals of the muscle flaps and wounds closure post operation, and the appearances of the donor sites and recipient sites during follow-up were observed. At the last follow-up, the shoulder joint function was evaluated using 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 satisfaction degrees of patients for appearance and function recoveries of shoulder were investigated by self-made questionnaire with reference to the concise test scoring system of shoulder joint. Results: All of the 13 muscle flaps around shoulder survived after surgery. Two patients had residual wounds in the skin grafting area, the wound in one of the patients was healed after dressing change, and the wound in the other 1 patient was healed with the second autologous split-thickness skin grafting on head after dressing change. During follow-up of 6 to 18 months for all the patients, the muscle flaps of patients were full in appearance and not bloated, and atrophic scar in the repaired area was soft in texture and closed with normal skin around. Linear suture scars were left in the donor sites of muscle flaps, which did not affect the overall appearance. At the last follow-up, the active abduction range of the shoulder joint was 60-90°, upward lift on 120-180°, muscle strength recovered to level Ⅳ and above in 8 cases and to level Ⅲ in 5 cases, and the shoulder joint function was evaluated as excellent in 8 cases and good in 5 cases; 10 patients were very satisfied and 3 patients were satisfied with the appearance and function recovery of the shoulders. Conclusions: The application of latissimus dorsi muscle flap provides a better choice for the muscle strength reconstruction around shoulder after electric burns, with good appearance of the operative areas and ideal prognosis of upper limb function.

[The impact of obstructive sleep apnea hypopnea syndrome on the perioperative and long-term outcome in patients with Stanford type A aortic dissection].

Objective: To confirm the impact of obstructive sleep apnea hypopnea syndrome (OSAHS) on perioperative and long-term outcome in patients with Stanford type A aortic dissection. Methods: From June 2010 to July 2017, the clinical data of 91 patients with Stanford type A aortic dissection were analyzed. Among them, 51 patients with OSAHS were included in the study group and 40 patients without OSAHS were included in the control group. After 36 months follow-up, all-cause death was regarded as the end event. The clinical baseline data, perioperative period and 36 months survival rate of the two groups were compared. Kanplan-Meier method was used to describe the 36 month survival curve of the two groups. Cox proportional risk model was used to evaluate the risk ratio (HR) and 95%CI of 36 month survival rate. Results: The mortality rate during hospitalization was 5.9% (3 cases) in the study group and 5.0% (2 cases) in the control group, and the difference was not statistically significant (χ~2=0.03, P>0.05). The actual follow-up was (36.2±1.5) months, 88 cases were followed up and 3 cases were lost. The all cause mortality rate of 36 months was 27.5% (14/51)in the study group and 10.0%(4/40) in the control group, the difference was statistically significant (χ~2=4.30, P<0.05).By Cox proportional risk model analysis, 36 months after operation, the study group was compared with the control group after adjusting for age, male, bicuspid of aortic valve, chronic obstructive pulmonary disease, anemia, preoperative pericardial tamponade, postoperative organ dysfunction, preoperative LVEF, emergency operation, Sun's operation, coronary artery bypass grafting, hypertension, cardiac arrhythmia, and advanced avulsion of distal aortic dissection The survival rate was lower, the difference was statistically significant (P<0.05).In addition to OSAHS, coronary artery bypass grafting and preoperative pericardial tamponade were also risk factors for the increase of 36 month mortality rate (HR=11.28,95%CI: 1.98-46.25, P=0.009; HR=9.08, 95%CI: 2.22-41.3, P=0.032). Conclusions: There was no significant difference in mortality during hospitalization in patients with Stanford A aortic dissection combined with OSAHS. The survival rate of 36 months after operation was lower than that of the control group.

[Analysis of occupational health status of radiation workers in Guangdong Province].

Objective: To discuss the effect of low-dose ionizing radiation on the health of radiation workers, and provide a basis for occupational health risk assessment of radiation workers. Methods: In January 2020, 3165 radiation workers who performed radiation occupational health examinations in Guangzhou Prevention and Treatment Hospital for Occupational Disease from January 2017 to December 2019 were selected as the research objects, and compared and analyzed the health status of radiation workers with different examination types (pre-job, in-job and off-job) , types of work, gender, and length of service. Results: The off-job occupational radiological health examination was rare at 2.3% (74/3165) . The abnormal detection rate of chest radiographs, renal function, thyroid function, and blood routine of the radiation workers in-job group was higher than that of the pre-job group (P<0.05) . No statistical difference was found in the abnormal detection rate of the examination items during the in-job group and the off-job group (P>0.05) . The blood routine abnormality detection rate of medical application group and industrial application group were higher than those of nuclear fuel group (P<0.05) . The abnormal detection rate of blood pressure and renal function of male radiation workers was higher than that of females, while the abnormal detection rate of blood routine of females was higher than that of males (P<0.05) . The abnormal detection rate of electrocardiogram, chest radiograph, blood pressure, renal function, thyroid function, and blood routine of radiation workers increased with increasing working age (P<0.05) . Conclusion: Occupational health status of radiation workers is not optimistic. Radiation occupational health monitoring should be strengthened, special attention should be paid to off-job radiation occupational health examination, focusing on the sensitive indicators of sensitive personnel, improving radiation protection conditions, and effectively protecting the occupational health of radiation workers.

[Short-term effect of sodium zirconium cyclosilicate on potassium lowering in chronic kidney disease patients with hyperkalemia].

Objective: To investigate the efficacy of sodium zirconium cyclosilicate on emergency correction of hyperkalemia in chronic kidney disease patients. Methods: Patients with chronic kidney disease who were admitted to the Department of Nephrology of the First Affiliated Hospital of Zhengzhou University from May to June 2020 were selected. Those who had hyperkalemia and took sodium zirconium cyclosilicate powder were finally included. The patient's clinical data and laboratory results were collected. Results: A total of 24 results were included from 21 patients. The age of patients was (48.9±13.5) years old. Fourteen patients were male, and 7 patients were female. After 2 hours of administration, the venous potassium level decreased from (5.85±0.52) mmol/L to (5.15±0.43) mmol/L (P<0.001, n=21), with an average decline of (0.71±0.43) mmol/L. Meanwhile, the arterial potassium level decreased from (5.50±0.40) mmol/L to (4.88±0.33) mmol/L (P<0.001, n=10), with an average decline of (0.62±0.29) mmol/L. Based on the initial venous potassium level, the patients were further divided into three groups. The average potassium decrease in<5.5 mmol/L group (4 patients), 5.5-<6.0 mmol/L group (11 patients) and ≥6.0 mmol/L group (6 patients) was (0.46±0.26) mmol/L, (0.62±0.38) mmol/L and (1.04±0.45) mmol/L, respectively. There was statistically significant difference of potassium reduction among the three groups (P=0.045). Moreover, the extent of potassium reduction was positively correlated with baseline venous potassium level (r=0.603, P=0.004, n=21). The study did not reveal any treatment-related adverse event. Conclusion: Sodium zirconium cyclosilicate powder can rapidly and effectively reduce the serum potassium level in chronic kidney disease patients with hyperkalemia.

[Clinical application of negative-pressure wound therapy in split-thickness skin grafting at hard-to-fix sites].

Objective: To compare the clinical effects of continuous negative-pressure wound therapy (NPWT) and conventional pressure dressing at at hard-to-fix sites after split-thickness skin grafting. Methods: From September 2017 to August 2019, 129 patients who met the inclusion criteria and had spilt-thickness skin grafting at hard-to-fix sites were admitted to the First Affiliated Hospital of Air Force Medical University and included in this retrospective cohort study. The patients were divided into NPWT group (67 patients, 41 males and 26 females, aged (32±6) years) and conventional pressure dressing group (62 patients, 37 males and 25 females, aged (30±5) years) according to whether the hard-to-fix sites were applied with NPWT after spilt-thickness skin grafting. After debridement and spilt-thickness skin grafting at hard-to-fix sites in patients of 2 groups, the wounds of patients in conventional pressure dressing group were applied with conventional pressure bandaging after being filled with dry gauze; for the wounds of patients in NPWT group, the semi-permeable membrane was pasted and sealed for continuous negative pressure suction after filled with dry gauze and placed the drainage foam or drainage tube, with the negative pressure ranging from -16.6 to -9.9 kPa. The bandage was opened during the first dressing change on the 5th day after surgery in NPWT group and on the 7th day after surgery in conventional pressure dressing group. The skin graft surviving area and proportion, the area and proportion of hematoma, the incidence of common complications of skin graft were observed and calculated. The times of postoperative dressing change and the length of hospital stay were counted. Data were statistically analyzed with two independent sample t test, Cochran & Cox approximate t test, chi-square test, and Fisher's exact probability test. Results: (1) At the first dressing change, the skin graft surviving area of patients in NPWT group was (420±94) cm(2), which was significantly larger than (322±97) cm(2) in conventional pressure dressing group (t'=12.33, P<0.01); the skin graft surviving area proportion of patients in NPWT group was (97.0±2.3)%, which was significantly higher than (74.4±4.8)% in conventional pressure dressing group (t'=50.11, P<0.01). (2) At the first dressing change, the skin hematoma area of patients in conventional pressure dressing group was (31.7±10.1) cm(2), which was significantly larger than (3.2±0.7) cm(2) in NPWT group (t'=23.04, P<0.01); the skin hematoma area proportion of patients in conventional pressure dressing group was (7.3±2.3)%, which was significantly higher than (0.7±0.3)% in NPWT group (t'=76.21, P<0.01). (3) At the first dressing change, there was 1 case of skin movement and no case of skin graft edge tear in NPWT group with an incidence of 1.5% (1/67). In the conventional pressure dressing group, there were 4 cases of skin movement and 2 cases of skin graft edge tear with an incidence of 9.7% (6/62), P<0.05. The incidence of complication of skin graft of patients in NPWT group was significantly lower than that in conventional pressure dressing group (P<0.05). (4) The times of postoperative dressing change of patients in NPWT group was significantly less than that in conventional pressure dressing group (t=7.93, P<0.01). The postoperative length of hospital stay in NPWT group was significantly less than that in conventional pressure dressing group (t=11.71, P<0.01). Conclusions: Continuous NPWT can effectively promote wound healing, improve the survival rate of skin graft, reduce the incidence of complications after skin grafting, and shorten the length of hospital stay in split-thickness skin grafting at hard-to-fix sites.

[Effects of pedicled anterolateral thigh flaps in repairing skin and soft tissue defects in perineal region caused by necrotizing fasciitis].

Objective: To explore the effects of pedicled anterolateral thigh flaps in repairing skin and soft tissue defects in perineal region caused by necrotizing fasciitis. Methods: From March 2014 to December 2018, 6 patients with skin and soft tissue defects in perineal region caused by necrotizing fasciitis were admitted to Department of Burns of Hanzhong Central Hospital (hereinafter referred to as our hospital). Two female patients had labia major defects and 4 male patients had scrotum defects, with age of 43-68 years. The areas of skin and soft tissue defects after debridement were 4%-8% total body surface area. The wounds in non-joint and non-functional area were repaired with free split-thickness skin grafts from medial femoral region, and the residual wounds areas in perineal region after repair were 10 cm×4 cm-22 cm×10 cm, which were repaired with pedicled anterolateral thigh flaps, with area of 12 cm×5 cm-24 cm×12 cm. The secondary wounds in the donor sites were sutured directly or repaired with free split-thickness skin grafts from medial thigh on the same or opposite side of the wounds. The bacterial culture result of wound exudate, drug sensitivity test result, and blood bacterial culture result on admission were recorded. The postoperative flap survival was observed. The length of hospital stay, debridement times, and antibiotics use time were recorded. The flap swelling condition was observed to evaluate whether flap thinning operation was necessary, the sensory recovery of the flap and hip joint activity were evaluated, and the scrotum function of male patients was evaluated by urologist in our hospital during follow-up. Results: The bacterial culture results of wound exudate in 5 patients on admission showed Escherichia coli with 4 of them having the same bacteria and the other one having methicillin-resistant Staphylococcus aureus detected in their blood samples. All the flaps survived in 6 patients after the operation, with total length of hospital stay of (22±5) d, debridement of 3-5 times, and antibiotics use time of (13±3) d. During follow-up of 3 to 6 months after the operation, the flaps were slightly bloated in 2 patients, and the flap thinning operation was performed 6 months after wound repair. The sensory function recovered to normal in 2 flaps of patients with anterolateral femoral cutaneous nerve, and the superficial sensory function in the other flaps of patients recovered in different degrees.The hip joint activity was close to normal in all the patients, and the scrotum function was normal in 4 male patients. Conclusions: The pedicled anterolateral thigh flap showed good effects in repairing skin and soft tissue defects on perineal region caused by necrotizing fasciitis, with good appearance and function after operation, and the method is simple, safe, and easy to apply.