Objective:To investigate the effects and mechanisms of angiotensin-converting enzyme 2 (ACE2) and Captopril (CAP) on mechanical ventilation-induced lung injury (VILI) in mice.Methods:Seventy-two healthy male BALB/c mice were randomly assigned (using a random number table) into six groups ( n=12 per group): normal control (NC) group, VILI group, ACE2 group, VILI+ACE2 group, CAP group, and VILI+CAP group. One hour prior to mechanical ventilation, the ACE2 and VILI+ACE2 groups were intraperitoneally injected with ACE2 at a dose of 0.1 mg/kg, while the CAP and VILI+CAP groups were intraperitoneally injected with CAP at a dose of 2.5 mg/kg. Following mechanical ventilation, serum samples were collected and enzyme-linked immunosorbent assay (ELISA) was used to detect inflammatory factors [platelet activating factor (PAF), endothelin-1 (ET-1), soluble intercellular adhesion molecule-1 (sICAM-1), prostaglandin E2 (PGE2)] and cardiovascular system related indicators [von Willebrand factor (vWF), thrombomodulin (TM), angiotensin (Ang) (1-9), Ang (1-7), prostacyclin I 2 (PGI2)]. Bronchoalveolar lavage fluid (BALF) was gathered, and total protein concentration was determined using BCA method, and sICAM-1 levels were measured by ELISA. Lung tissues were collected and subjected to hematoxylin and eosin staining (HE staining) for the assessment of pathological lung injury and lung injury scoring. Western blot and reverse transcription quantitative polymerase chain reaction (RT-qPCR) were utilized to detect the relative expression levels of ACE2 protein and mRNA, respectively. Statistical analysis was performed using IBM SPSS 20.0 software. Intergroup comparisons were conducted using one-way analysis of variance followed by the least significant difference (LSD) test. Results:No statistically significant differences were observed in the levels of PAF, ET-1, sICAM-1, vWF, TM, Ang(1-9), Ang(1-7), and PGI2 in serum and lung tissues between the ACE2/CAP groups and the NC group (all P>0.05). Compared with the VILI group, the VILI+ACE2 and VILI+CAP groups exhibited significantly decreased serum and lung tissue levels of PAF, ET-1, sICAM-1, and vWF (all P<0.05), while the levels of TM, Ang(1-9), Ang(1-7), and PGI2 were significantly increased (all P<0.05). Pathological lung injury was alleviated, and the lung wet/dry weight ratio was significantly reduced (all P<0.05) in the VILI+ACE2 and VILI+CAP groups. Furthermore, both ACE2 protein and mRNA expression levels were significantly increased in these groups (all P<0.05). Conclusion:Both ACE2 and CAP can inhibit inflammation and protect the cardiovascular system, possibly by promoting the ACE2/Ang(1-9)/Ang(1-7) axis, thereby exerting a protective effect against VILI.

Objective:To develop an efficient and rapid method for the isolation and cultivation of human scalp dermal papilla cells from small specimens.Methods:Hair-bearing skin specimens measuring 0.5 cm × 0.5 cm -0.5 cm × 1 cm in size were obtained from the scalp of 3 patients with pigmented nevus and 6 with sebaceous nevus during surgery in Department of Dermatology, the First Hospital Affiliated to Army Medical University from September 2018 to January 2019. The subcutaneous fat layer containing hair follicles was cut out of the specimens, and hair follicles were sorted with ophthalmic forceps, which were subsequently digested with 0.6% dispase Ⅱ for 30 minutes, then with 0.2% collagenase Ⅳ at 37 ℃ for 30 - 60 minutes, and were centrifuged to obtain hair papillae. Morphological observation was performed on the isolated hair papillae, and dermal papilla cells were cultured, passaged and identified.Results:Under the microscope, the hair papillae isolated by two-step enzyme digestion of small scalp specimens were intact, and showed an inverted pear-like shape, and residual dermal sheaths could be observed around some hair papillae. However, no hair papilla was isolated by one-step enzyme digestion. With the two-step enzyme digestion method, the hair papilla separation rate was 60.8% ± 2.1%, the adherence rate of the dermal papilla cells at 72 hours was 86.6% ± 3.9%, the time for cells to emigrate out of hair papillae was 0.5 - 3.0 days, the total operation duration was 2.0 - 3.0 hours, and the actual operation duration after subtraction of digestion duration was 1.0 - 1.5 hours. The dermal papilla cells isolated by the two-step enzyme digestion method could grow in an aggregative pattern in early stage, but grew in a non-aggregative pattern after 8 passages.Conclusion:The two-step enzyme digestion of small specimens is a simple and efficient method for isolating human scalp dermal papilla cells.

Objective To establish a non-venous bypass orthotopic liver transplantation model in Bama miniature pigs with high repeatability and stability. Methods Twelve Bama miniature pigs were randomly divided into the donor group (n=6) and recipient group (n=6). Pigs underwent non-venous bypass orthotopic liver transplantation. The time of anhepatic phase during operation was shortened, blood pressure during anhepatic phase was stably maintained, and management of anesthesia and body fluid during operation were strengthened. The operation time, anhepatic phase and survival status of the recipients were observed and recorded. The intraoperative heart rate, mean arterial pressure (MAP) and changes in arterial blood gas analysis were monitored. The perioperative liver function was evaluated. Results Among 6 Bama miniature pigs, 1 died from transplantation failure intraoperatively. The operation time of the remaining 5 pigs was (247±27) min and the time of anhepatic phase was (46±4) min. Three animals survived for more than 2 weeks. Compared with the preanhepatic phase, the heart rate of the animals was significantly faster, MAP was considerably reduced to (46±6) mmHg, blood pH value, base excess (BE) and HCO₃^- level were all significantly decreased and serum level of K⁺ was significantly elevated during the anhepatic phase (all P < 0.05). In the neohepatic phase, MAP of Bama miniature pigs was significantly increased, heart rate was dramatically slower.Blood pH value, BE, HCO₃^- level were significantly increased and serum level of K⁺ was significantly declined (all P < 0.05). During abdominal closure, MAP, blood gas indexes and serum level of K⁺ were almost recovered to those in the preanhepatic phase. Compared with preoperative levels, the levels of alanine aminotransferase(ALT), aspartate aminotransferase(AST), lactate dehydrogenase(LDH)and alkaline phosphatase(ALP)were significantly increased after operation (all P < 0.05), the change in AST was the most obvious, and it gradually decreased at postoperative 2 d. The level of γ-gutamyl transferase(GGT) did not significantly elevated. The level of total bilirubin (TB) was evidently elevated at postoperative 5 d. Compared with the preoperative levels, the levels of total protein (TP) and albumin (ALB) were significantly decreased after operation (both P < 0.05), and began to gradually increase at postoperative 1 d. Conclusions The non-venous bypass orthotopic liver transplantation model of Bama miniature pig is convenient, with highly reproducible and survival rate, which can be utilized as a standardized liver transplantation model.

The detection of R-wave of ECG is essential to the analysis of the heart rate variability (HRV). In this paper, an R-wave detection method using wavelet transform(WT) is presented in line with the principle of discrete wavelet transform(DWT) and multi-resolution technique (MRT). We made use of the special properties of dbl wavelet in time-domain, decomposed the original ECG signals into 3-level detailed signals on different frequency bands by using DWT with Mallat algorithm, and got appropriate threshold values in different high frequency bands to distinguish R-wave. It is concluded that the algorithm had significant effects on it, which is verified by MIT/BIH (Massachusetts Institute of Technology/Boston's Beth Israel Hospital) ECG Database. The results show that R-wave could be detected accurately and localized precisely by this method, even when the patient was seriously sick or the signal was disturbed by noise. Consequently the method has a quite high locating precision (its error is not more than two sampled points and about 85 percent of the points of R-wave in ECG signal are localized precisely) and the correct detection rate of R-wave is 99.8% by using wavelet transform, so this method is quite feasible.
Algorithms ; Electrocardiography ; Heart Rate ; physiology ; Humans ; Signal Processing, Computer-Assisted