Objective To construct an assay for early infection diagnosis of Angiostrongylus cantonensis based on gold nanorod polymerization.Methods Stable gold nanorods were synthesized by the gold seed growth method,and labeled with different concentrations of sulfhydrylated crude and purified antigens of lar-vae and adults of Angiostrongylus cantonensis,and their excretory and secretory antigens,and then scanned the longitudinal surface plasmon resonance(LSPR)of the stable gold nanorods by ultraviolet-visible(UV-Vis)spectrophotometry,and screened for the optimal labeled antigens for the detection of different infection time after infection of rats with Angiostrongylus cantonensis.The displacement changes were screened to se-lect the best labeled antigens for the detection of serum antibodies and positive sera of series of dilution gradi-ents at different infection times(5,7,14,21 d)after infection with Angiostrongylus cantonensis in rats,and at the same time,the enzyme-linked immunosorbent assay(ELISA)was set up for the same test.Kappa test was used to compare the consistency of the two assays.Results Gold nanorods with stable aspect ratio were suc-cessfully prepared.The gold nanorods labeled with 10 μg/mL of adult purified antigen had a maximum LSPR shift of 40 nm,and were able to detect serum antibodies in rats 5 d after mild,moderate and severe infection with Angiostrongylus cantonensis,as well as positive sera at a maximum dilution of 1∶600.The ELISA was able to detect serum antibodies in rats after 14 d of mild infection,and 7 d of moderate and severe infection,as well as positive sera at a maximum dilution of 1∶200.The ELISA detected positive serum antibodies in rats after 14 d of mild infection and 7 d of moderate and severe infection,as well as in rats at a maximum dilution of 1∶200.The Kappa value of the two methods was 0.750(P<0.01),and the results of the two methods had strong consistency.Conclusion A polymerized gold nanorod assay for early and rapid diagnosis of An-giostrongylus cantonensis infection is successfully constructed.

Objective:To learn about the infection and gene polymorphisms of hepatitis E virus (HEV) in murine-shaped animals of plague foci in Yunnan Province.Methods:From July to August 2019, around 16 natural villages (4 in Mile City, 6 in Mangshi and 6 in Lianghe County), which were the foci of domestic plague in Yunnan Province, the murine-shaped animals were captured by the night-time method. The liver RNA was extracted, and the target gene of rat HEV was detected by one-step real-time fluorescence quantitative PCR, and the positive rate of rat HEV was calculated. The rat HEV positive samples were amplified by PCR for further clone sequencing, and the resulting sequences were compared with the HEV sequences registered in the GenBank and a phylogenetic tree was constructed by using MegAlign and MEGA 7.0.Results:A total of 491 murine-shaped animals were captured from 3 orders, 5 families, 8 genera, 15 species, and the positive rate of rat HEV was 4.89% (24/491). Among them, the positive rate of Rattus tanezumi and Niviventer fulvescens was 9.39% (23/245) and 1/3, respectively; and other species were negative. There was a statistically significant difference in the positive rate of rat HEV between different habitats ( P = 0.014), and the positive rate of rat HEV in the habitats near the dwellings was higher than that in other habitats ( P < 0.05). The sequence comparison analysis showed that the gene sequence of P018 from Lianghe County was 100.0% homologous to the MG813927.1 sequence of the first patient with rat HEV in Hongkong, and it was clustered into the same branch with the sequences of MG813927.1 and LC549185.1 from rat, was the type HEV C. G024 from Mangshi shared a low homology (20.7% - 31.5%) with other virus strains, and it was clustered into the same branch with a HEV sequence from an avian (AY535004.1). Conclusions:Rat HEV is prevalent in murine-shaped animals of plague foci of Yunnan Province, and there may be gene polymorphisms of rat HEV. In addition, the difference infection rate may be related to the habitats.

Objective:To compare the cuff pressure and leakage volume and the related complications of filling the tracheal tube cuff by minimum air leakage method and cuff pressure manometer method after endotracheal intubation, so as to provide theoretical basis for patients who was intubated to obtain appropriate cuff pressure.Methods:A prospective randomized controlled study was conducted. 100 patients admitted to the department of critical care medicine of the Fifth Center Hospital in Tianjin from December 2015 to June 2019 were enrolled. According to the random number table method, the patients were divided into the experimental group and control group, with 50 patients in each group. After successful endotracheal intubation, all patients were placed in a supine position with the head of the bed raised by 30°. The experimental group used the minimum air leakage method, and used the cuff pressure manometer to obtain the cuff pressure. In the control group, cuff pressure was maintained at 25-30 cmH 2O (1 cmH 2O = 0.098 kPa). Parameters such as cuff pressure and ventilator leakage volume at the beginning and 4 hours, 8 hours after the inflation were compared between the two groups, as well as the incidence of ventilation-associated pneumonia (VAP) and airway complications after extubation. Results:Among the 100 cases, 53 were males and 47 were females. The age ranged from 23 to 87 years old, with an average of (68.53±8.46) years old. The intubation time ranged from 1 to 16 days.① At 4 hours and 8 hours after inflation, the cuff pressures of the two groups were lower than that of the first time of inflation, and the air leakage of the ventilator increased gradually with the extension of time. Compared with the control group, cuff pressures at each time point in the experimental group were significantly higher than those in the control group [mmHg (1 mmHg = 0.133 kPa): 33.72±9.14 vs. 25.68±5.26 at 0 hour, 30.54±7.81 vs. 24.35±4.93 at 4 hours, 26.57±5.64 vs. 22.42±4.14 at 8 hours, all P < 0.05], and ventilator leakage volumes were smaller than those in the control group (mL: 25.57±8.51 vs. 34.65±9.47 at 0 hour, 40.54±8.51 vs. 60.34±7.85 at 4 hours, both P < 0.05). ② The incidence of VAP in the experimental group was significantly lower than that in the control group (4% vs. 10%, P < 0.05). There was no statistically significant difference in the incidence of other airway complications between the experimental group and control group (airway mucosal edema: 14% vs. 12%, ulcer: 8% vs. 6%, tracheal esophageal fistula: 0% vs. 0%, hoarseness: 4% vs. 6%, cough: 30% vs. 34%, sore throat: 28% vs. 32%, tracheal softening: 0% vs. 0%, cuff rupture: 10% vs. 8%, all P > 0.05). Conclusions:The optimal cuff pressure is very important for preventing VAP and reducing airway complications. The minimum air leakage method makes the clinical obtained endotracheal intubation cuff pressure more accurately, with less air leakage, safe and effective, and it is worthy of clinical promotion.