Since the outbreak of COVID-19 caused by the 2019-nCoV (SARS-CoV-2), with its high pathogenicity and contagiousness, it has posed a serious threat to global public health security. Up to now, the pathogenesis of 2019-nCoV is unclear, and there is no effective treatment. Vaccine as one of the most effective strategies to prevent virus infection has become a hot area. Based on the current understanding of 2019-nCoV, the development of 2019-nCoV vaccines covers all types: inactivated virus vaccine, recombinant protein vaccine, viral vector-based vaccine, mRNA vaccine, and DNA vaccine, etc. In this review, we focus on the candidate targets of the novel coronavirus, and the types, development status and progress of 2019-nCoV vaccines in order to provide information for further research and prevention.

Objective To evaluate the efficacy of WeChat platform conbined with problem-based learning (PBL) teaching method when applied to the standardized training for residents in a department of anesthesiology.Methods Ninety-six residents who were undergoing the standardized training in the Department of Anesthesiology of our hospital were divided into 3 groups (n =32 each) using a random number table:lecture-based learning teaching method group,PBL teaching method group and WeChat platform plus PBL teaching method group.The examination scores after the end of teaching,satisfaction with teaching and scores of interest in anesthesiology were recorded.Results The total scores of examination,scores of comprehension memory problems,clinical application problems and comprehensive analysis problems,rate of satisfactory teaching and scores of interest in anesthesiology were significantly higher in WeChat platform plus PBL teaching method group than in the other two groups (P＜0.05).Conclusion WeChat platform combined with PBL teaching method can improve the teaching quality of the standardized training for residents in a department of anesthesiology and win praise from residents,and it is worth promoting the application.

Objective:To study the clinical effect of Mammotome minimally invasive breast circumcision in the treatment of breast cancer.Methods:A prospective study was carried out in 800 breast benign tumor patients admitted to the People's Hospital of Anji County from January 2017 to December 2018.The patients were divided into control group(400 cases) and observation group(400 cases) according to the random digital table method.The control group received open breast tumor resection, and the observation group received minimally invasive mastectomy.The postoperative complications, recovery time, aesthetic effect of breast appearance, serum inflammatory factors and cellular immune function were compared between the two groups.Results:The operation time and bleeding volume in the observation group were (17.59±8.23)min, (23.57±7.64)mL, respectively, which were lower than those in the control group [(29.83±11.91)min, (54.28±17.59)mL]( t=16.910, 30.027, all P<0.05). The incidence of postoperative complications in the observation group was 1.50%(6/400), which was lower than 5.75%(23/400) in the control group(χ 2=10.340, P<0.05). The time of incision healing and hospitalization in the observation group were (4.07±1.39)d, (5.58±2.31)d, respectively, which were shorter than those in the control group [(5.56±1.75)d, (7.92±2.78)d]( t=13.334, 12.948, all P<0.05). The excellent and good rate of breast appearance aesthetics in the observation group was 97.25%(389/400), which was higher than 89.25%(357/400) in the control group(χ 2=20.336, P<0.05). After operation, the serum levels of inflammatory factors in the observation group were lower than those in the control group( t=17.360, 14.717, 14.109, all P<0.05). CD 3+ and CD 4+ /CD 8+ in the two groups were lower than before operation(control group: t=20.788, 16.121; observation group: t=11.616, 8.348, all P<0.05), and CD 3+ and CD 4+ /CD 8+ in the observation group were higher than those in the control group( t=10.655, 7.328, all P<0.05). Conclusion:Mammotome minimally invasive mastectomy can effectively reduce the surgical trauma of breast cancer patients, reduce the postoperative complications, reduce the impact on their cellular immune function, and help to speed up the recovery and improve the appearance of breast.

Objective:To explore whether chronic fluorosis can cause liver fibrosis in rats by observing expression changes in type Ⅰcollagen (Col-Ⅰ), type Ⅲ collagen (Col-Ⅲ) and alpha smooth actin (α-SMA) in the liver tissue of chronic fluorosis rats.Methods:According to body weight (90 - 100 g), forty-eight SD rats were randomly divided into control group (drinking water fluoride ion concentration < 0.5 mg/L), low, medium and high concentration fluoride groups (drinking water fluoride ion concentration of 5.0, 50.0 and 100.0 mg/L), with 12 rats in each group (half male and half female), and fed for 6 months. Fluoride ion selective electrode method was used to detect bone fluoride and urinary fluoride levels; hematoxylin-eosin staining (HE staining) and Masson staining were used to observe the pathological and morphological changes and the collagen deposition of liver tissue; quantitative real-time polymerase chain reaction and immunohistochemical staining were used to observe Col-Ⅰ, Col-Ⅲ and α-SMA mRNA and protein expressions.Results:There was significant difference in bone fluoride and urine fluoride between the 4 groups [bone fluoride: (92.52 ± 5.64), (112.21 ± 11.86), (142.99 ± 7.87), (235.63 ± 11.55) mg/kg; urinary fluoride: (5.47 ± 0.88), (17.78 ± 1.48), (54.16 ± 5.96), (121.11 ± 6.32) mg/L, P < 0.001]. Under light microscope, with the increase of fluoride concentration, the degree of hepatic cell edema was aggravated, and the deposition of collagen fiber around the central vein and the portal area increased significantly. The mRNA expression level of Col-Ⅰ in low, medium and high concentration fluoride groups (1.20 ± 0.09, 1.80 ± 0.08, 1.58 ± 0.06) was significantly higher than that in control group (1.00 ± 0.00, P < 0.05); Col-Ⅲ and α-SMA mRNA expression levels in medium and high concentration fluoride groups (Col-Ⅲ: 1.15 ± 0.14, 1.64 ± 0.24; α-SMA: 1.69 ± 0.02, 2.34 ± 0.06) were significantly higher than those of low concentration fluoride group (Col-Ⅲ: 0.59 ± 0.17; α-SMA: 0.80 ± 0.13, P < 0.05). With the increase of fluoride concentration, the liver tissue Col-Ⅰ(0.00 ± 0.00, 0.03 ± 0.01, 0.08 ± 0.01, 0.13 ± 0.02), Col-Ⅲ (17 803.05 ± 3 221.16, 47 523.15 ± 3 490.10, 127 786.35 ± 13 008.86, 237 233.03 ± 47 614.63) and α-SMA (516.83 ± 181.18, 2 885.03 ± 864.92, 11 186.94 ± 2 394.08, 37 182.43 ± 12 390.59) protein levels were also increased significantly ( P < 0.05). Conclusion:Long-term excessive intake of fluorine may cause the production of collagen fibers around the central vein and the portal area of the liver in rats to increase, and then lead to the formation of liver fibrosis.

Objective:To explore the clinical effects of parallel combined flow-through perforator flaps in the treatment of circular hot crush injuries in limbs with blood supply disorder.Methods:The study was a retrospective observational study. From April 2016 to December 2022, 4 cases with circular hot crush injuries in limbs with blood supply disorder were admitted to the Department of Burns and Plastic Surgery of the 988 th Hospital of Joint Logistics Support Force of PLA, including 3 males and 1 female, aged from 24 to 48 years. Among them, 2 cases were injured in the calf and 2 cases were injured in the forearm. After emergency debridement, the area of skin and soft tissue defects was from 20 cm×20 cm to 44 cm×20 cm. The patients had defects in tibialis anterior and posterior tibial arteries with a length of 13 to 18 cm, and in ulnar and radial arteries with a length of 9 to 12 cm. Flaps were designed and cut, including a flow-through anterolateral thigh perforator flap with area of 20 cm×9 cm to 24 cm×21 cm carrying the descending branch of the lateral circumflex femoral artery and the accompanying veins of 8 to 18 cm in length; and a flow-through posterior tibial artery perforator flap with area of 21 cm×13 cm and 20 cm×14 cm carrying the posterior tibial artery, the accompanying veins with a length of 14 and 17 cm respectively, and the great saphenous vein with a length of 22 and 21 cm. The circular hot crush injury wounds in the calf with blood supply disorder were repaired by a parallel combination of flow-through posterior tibial artery perforator flap and flow-through anterolateral thigh perforator flap, and the circular hot crush injury wounds in the forearm with blood supply disorder were repaired by a parallel combination of bilateral flow-through anterolateral thigh perforator flap, and the injured main vessels were reconstructed. The donor site wounds of flap were closed directly or treated with split-thickness skin grafts from abdomen. After surgery, the blood supply and survival of the flap and distal affected limb, the healing of wounds in the donor and recipient sites, the survival of the skin graft in the flap donor site were observed. During follow-up, the condition of flaps, the appearance, blood supply, and function of affected limbs were observed. At the last follow-up, the foot and ankle functions were evaluated according to the scoring standards of American Orthopedic Foot and Ankle Association, and the wrist and hand function was evaluated according to the trial standard of replantation of amputated upper limb function assessment of the Hand Surgery of Chinese Medical Association. Results:The flaps and distal affected limbs of 4 patients had good blood circulation and successfully survived after surgery. The wounds of 3 cases successfully healed, while one patient with circular hot crush injury in the forearm experienced exudation in the recipient site in the later stage, and the wound healed after re-expansion and suturing. The donor site wounds healed smoothly, and the skin grafts successfully survived. During follow-up of 12 to 24 months after surgery, the flaps were slightly swollen, the limbs had good appearance, normal blood circulation, and fine functional recovery. At the last follow-up, the foot and ankle function of 2 patients with circular hot crush injuries in the calf was evaluated as good in 1 case and commonly in 1 case; the wrist and hand function of 2 patients with circular hot crush injuries in the forearm was evaluated as excellent in 1 case and good in 1 case.Conclusions:The parallel combined flow-through perforator flap can reconstruct the damaged main blood vessels and repair the wound at the same time. It can not only effectively save the limb, but also restore part of the function of the affected limb. It is one of the effective methods to treat the circular hot crush injuries in limbs with blood supply disorder.