Objective To study the effect of self-modified Guth & Samaha's myosin-ATPase staining method on the classification of SD rat skeletal muscle fiber types.Methods 8 ?m-thick cryostat sections from rat chest muscles and biceps brachii muscles were transfected with cryostat.Myosin-ATPase staining was carried out according to the following procedure: ① Fixing sections for 5 min in fixative solution containing 40 g/L paraformaldehyde;② Rinsing slides in Tris-rinse solution and then preincubating them in alkaline preincubation solution for 15 min;③ Rinsing slides in Tris-rinse solution twice and then incubating them for 60 min in incubation solution;④ Washing slides for three times in 10 g/L CaCl2 and then placing them in 20 g/L CoCl2 for 3 min;⑤ Washing sides in distal water and then placing them in 10 g/L(NH4)2S for 3 min and;⑥ Washing slides in running tap water for 3 min,dehydrating in graded ethanol,clearing in xylene and mounting in neutral balsam.Results After being stained by modified myosin-ATPase staining method,both chest muscle and biceps brachii muscle samples from SD rats could be clearly identified as type Ⅰ fibers and type Ⅱfibers as the fibers of type Ⅰ were stained white while the fibers of type Ⅱ were stained brown.Conclusion Modified myosin-ATPase staining method is a simple and effective way for muscle fiber type classification and can be applied in skeletal muscle related study.

Human embryonic stem ceIIs(hESC),characterized by unique capacities of seIf-renewaI and differentiation into cardiomyocytes and hepatocytes,can be used in new drug screening and drug safety evaIuation processes. Cardiotoxicity and hepatotoxicity are major obstacIes to deveIopment and marketing of new drugs. hESC-derived cardiomyocytes and hepatocytes have structuraI and functionaI characteristics,which can be used for cardiotoxicity and hepatotoxicity testing in vitroand for buiIding a drug safety evaIuation system invitrothat has the advantage of short experiment cycIes,smaII dose,Iow cost and few species differences. hESC-derived cardiomyocytes and hepatocytes have broad prospects of appIication in toxicoIogy.

Objective To establish the SD rat aortic dissection(AD)model by using both BAPN and AngⅡ,in order to investigate AD's pathogenesis. Methods 90 three weeks old SD rats were equally divided into three groups randomly:control group,medicine gavage group and blank medicine gavage group. Rats in control group were fed on a regular diet;BAPN ( 1g/ kg per day)was forced into rats'stomach in the medicine gavage group;the same volume saline was forced into rats' stomach in the blank medicine gavage group. 4 weeks later,when the rats were 7 weeks old,we stopped giving them BAPN, but to implant an omicro-osmotic pump subcutaneously in the abdomen. The pumps in control group and blank medicine gavage group were filled with 0. 9％ saline,the medicine gavage group'pumps were filled with AngⅡsolution( 1 μg·kg- 1 ·min- 1 ). 1 week later,all the survivals were dissected after anesthesia and the aortic vessels were acquired. All the acquired aortic ves-sels were proceed pathological examination. All the rats dead during the process of the experiment were dissected immediately to get the aortic vessels and proceed pathological examination. Results All rats in control group and blank medicine gavage group were survival,there was no aortic dissection or death. In medicine gavage group, 15 rats developped aortic dissection, 12 a-mong them were died of aortic dissection rupture,the aortic dissection formation rate was 50％ . Conclusion Using BAPN and AngⅡ to establish the SD rat AD model is feasible,it is simple and practicable,meanwhile,it has high aortic dissection for-mation rate. The process is similar with human's aortic dissection process.

The accuracy of the Sepsis-3 definition in the diagnosis of sepsis has been widely accepted and applied. Indicators such as Procalcitonin(PCT), white blood cell(WBC), C-reactive protein(CRP), platelets(PLT) and albumin are the most extensively and conveniently applied in early alert and diagnosis of urinary sepsis. PCT has a higher specificity and sensitivity compared to other biomarkers, and a sharp drop in WBC is a strong warning for septic shock. However, CRP has a relatively low specificity. IL-6, CD64, Presepsin, miRNA, and PTX-3, among others, are more valuable emerging indicators with higher sensitivity and specificity. However, uniform and standardized technology is necessary for a high quality testing. The combination of multiple biomarkers with a clinical scoring system is more useful than individual biomarkers clinically. This article mainly reviewed the progress of research on indicators related to early alert and diagnosis of urinary sepsis during recent years.

Background: During hot environment work tasks with whole-body enclosed anti-bioaerosol suit, the combined effect of heavy sweating and exhaled hot humid air may cause the N95 medical respirator to saturate with water/sweat (i.e., water-blocking). Methods: 32 young male subjects with different body mass indexes (BMI) in whole-body protection (N95 medical respirator + one-piece protective suit + head covering + protective face screen + gloves + shoe covers) were asked to simulate waste collecting from each isolated room in a seven-story building at 27-28°C, and the weight, inhalation resistance (Rf), and aerosol penetration of the respirator before worn and after water-blocking were analyzed. Results: All subjects reported water-blocking asphyxia of the N95 respirators within 36-67 min of the task. When water-blocking occurred, the Rf and 10-200 nm total aerosol penetration (Pt) of the respirators reached up to 1270-1810 Pa and 17.3-23.3%, respectively, which were 10 and 8 times of that before wearing. The most penetration particle size of the respirators increased from 49-65 nm before worn to 115-154 nm under water-blocking condition, and the corresponding maximum size-dependent aerosol penetration increased from 2.5-3.5% to 20-27%. With the increase of BMI, the water-blocking occurrence time firstly increased then reduced, while the Rf, Pt, and absorbed water all increased significantly. Conclusions This study reveals respirator water-blocking and its serious negative impacts on respiratory protection. When performing moderate-to-high-load tasks with whole-body protection in a hot environment, it is recommended that respirator be replaced with a new one at least every hour to avoid water-blocking asphyxia.

Objective:To study the relationship of pathogenic bacteria in midstream urine culture and stone composition of patients characteristics with infection stones.Methods:Between January 2016 and December 2020, 989 patients with infectious stones who attended Tsinghua Chang Gung Hospital, affiliated with Tsinghua University, for surgical treatment were enrolled in the study. There were 545 male and 444 female patients, with the mean age (48±14) years. The left and right side stones were 396 and 333, respectively. There were 260 bilateral stones, 264 single stones, 334 multiple stones, and 391 deer-stalker-shaped stones. The maximum diameter of stones was (33.4±26.5)mm, combined with diabetes in 109 cases and hypertension in 235 cases. Clean middle-urine was collected for bacterial culture, and intraoperative stone specimens were collected by percutaneous nephrolithotomy (PCNL). Personal characteristics of the patient such as gender, age, body mass index, clinical information such as stone size, location, comorbidities, results of urine culture and stone composition were recorded. The differences of infectious stone composition was analyzed between urease-producing, non-urease-producing bacteria.Results:Among the 989 patients with infectious stones, 259 were pure infectious stones, 131 were mixed infectious stones, and 599 were combined with infectious stone components. Urine cultures were positive in 627(63.4%) patients with infectious stones. The predominant urease-producing bacteria included Ureaplasma urealyticum(94 case), Proteus mirabilis(58 case), and Staphylococcus spp.(36 case). Pure infectious stones were common in Proteus mirabilis, while combined with infectious stone components were common in Ureaplasma urealyticum and Staphylococcus spp. The predominant non-urease-producing bacteria included Escherichia coli(175 case), Enterococcus spp.(76 case) and Streptococcus spp.(35 case). Escherichia coli commonly contained in infectious stone components and pure infectious stones, whereas Enterococcus spp. and Streptococcus spp. commonly contained in infectious stone components. Escherichia coli (61 case), Proteus mirabilis (44 case) and Enterococcus spp.(20 case) were the most common bacteria in 259 cases of pure infectious stones. Escherichia coli (36 case), Enterococcus spp. (14 case) and Ureaplasma urealyticum (10 case) were the most common bacteria in 131 cases of mixed infectious stones. The most common bacteria in 599 cases of combined infectious stones were Escherichia coli (78 case), Ureaplasma urealyticum (68 case) and Enterococcus spp. (42 case).Conclusions:Urease producing bacteria were not common in infectious stones. It was common for the Ureaplasma urealyticum in combined infectious stone components, while Escherichia coli was common in pure and combined infectious stone components.

During coronavirus disease 2019 epidemic, the treatment of severe trauma has been impacted. The Consensus on emergency surgery and infection prevention and control for severe trauma patients with 2019 novel corona virus pneumonia was published online on February 12, 2020, providing a strong guidance for the emergency treatment of severe trauma and the self-protection of medical staffs in the early stage of the epidemic. With the Joint Prevention and Control Mechanism of the State Council renaming "novel coronavirus pneumonia" to "novel coronavirus infection" and the infection being managed with measures against class B infectious diseases since January 8, 2023, the consensus published in 2020 is no longer applicable to the emergency treatment of severe trauma in the new stage of epidemic prevention and control. In this context, led by the Chinese Traumatology Association, Chinese Trauma Surgeon Association, Trauma Medicine Branch of Chinese International Exchange and Promotive Association for Medical and Health Care, and Editorial Board of Chinese Journal of Traumatology, the Chinese expert consensus on emergency surgery for severe trauma and infection prevention during coronavirus disease 2019 epidemic ( version 2023) is formulated to ensure the effectiveness and safety in the treatment of severe trauma in the new stage. Based on the policy of the Joint Prevention and Control Mechanism of the State Council and by using evidence-based medical evidence as well as Delphi expert consultation and voting, 16 recommendations are put forward from the four aspects of the related definitions, infection prevention, preoperative assessment and preparation, emergency operation and postoperative management, hoping to provide a reference for severe trauma care in the new stage of the epidemic prevention and control.