Objective To investigate the effects of surgical trauma on synaptic structure in hippocampal CA3 area in aged rats.Methods Fifty-six healthy SD rats aged 18 months were randomly divided into 3 groups: control group (group C, n = 8) , anesthesia group (group A, n = 24) , and operation group (group O, n - 24) . Anesthesia was performed with intraperitoneal ketamine 40 mg/kg but no operation was carried out in group A. Anesthesia was also performed with intraperitoneal ketamine 40 mg/kg, and splenectomy was performed after loss of righting reflex in group O. Eight animals from group A and O selected on 1, 3, and 7 d after anesthesia or operation respectively underwent Morris water maze test for assessment of the cognitive function. The animals were . then decapitated. Hippocampal CA3 area was isolated for examination with electron microscope and the synaptic structure in the polymorphic layer of hippocampal CA3 area was measured. Results Compared to group C and A, the times of passing through the original platform and number of synapses were significantly reduced, the width of synaptic cleft was significantly increased, the thickness of the postsynaptic density was significantly decreased, the length of the active zones was significantly shortened, and the curvature of the synaptic interface and percentage of perforated synapses were significantly decreased at T_(1,2), ( P < 0.05 or 0.01) , but no significant change was found in the indices mentioned above at T_3 in group O(P > 0.05). Compared to group C, the latency and swimming distance were significantly prolonged at T_1 in group A and at T_(1,2) in group O ( P < 0.01) . Compared to group A, the latency at T_(1,2) and the swimming distance at T_2 were significantly prolonged in group O ( P < 0.05) . Conclusion Surgical trauma can induce early postoperative cognitive impairment through changing synaptic structure in hippocampal CA3 area in aged rats.

Objective To evaluate the efficacy of ultrasound for placement of laryngeal mask airway (LMA) in comparison with fiberoptic bronchoscope in adult patients.Methods Fifty-eight ASA physical status Ⅰ or Ⅱ patients,aged 18-57 yr,weighing 50-70 kg,with body mass index 20-30 kg/m2,scheduled for gynecological operation under general anesthesia,underwent standard general anesthetic technique with 4 # LMA-ClassicTM.After clinical assessment of correct placement of LMA,the position of the LMA was confirmed by transverse neck ultrasound,and reconfirmed using fiberoptic bronchoscopy.The peak airway pressure and oropharyngeal leak pressure were recorded.Results When the outcome of clinical assessment of correct placement of LMA was considered as satisfactory,the rate of ideal anatomic placement assessed by ultrasound evaluation was 69 %,and the rate of ideal anatomic placement assessed by fiberoptic bronchoscopy was 59 %,and it showed that there was no significant difference in detecting the ideal placement of the LMA (P ＞ 0.05).The oropharyngeal leak pressure was significantly higher when ultrasound was used for confirmation of the correct placement of LMA than that when fiberoptic bronchoscope was used (P ＜ 0.05).Conclusion Ultrasound provides better efficacy for placement of LMA in indicating sealing of LMA than fiberoptic bronchoscope and is helpful in improving ventilation conditions in adult patients.

In this study ,we analyzed the genetic characterizations and propagation paths of measles viruses prevalent in Ningbo ,China from 2004 to 2013 .Measles viruses were isolated from throat swab specimens from 2004 to 2013 ,and 450 bp fragments of C terminus of nucleoprotein (N) gene were amplified by RT-PCR .Sequence analysis was conducted of all 31 virus strains ,and then compared with other measles virus strains published in GenBank .Results showed that all the 31 measles virus isolates belonged to genotype H1 ,6 strains (one strains in 2004 and 5 ones in 2005) belonged to H1b subtype ,and others be-longed to H1a subtype .Compared the 31 strains to the China 93-4 and China 94-7 ,the homology of 450 bp fragments of C ter-minus of nucleoprotein (N) gene were 97 .1%-100% and 96 .7%-100% ,respectively .The homology of 450 bp fragments of nu-cleotide and nucleotide (amino acids) compared with S191 were 81 .9%-92 .4% and 87 .2%-90 .6% ,respectively .It’s suggested that genotype H1 measles virus circulated in Ningbo from 2004 to 2013 ,and H1a was the predominant epidemic strain ,and H1b strain was existed as well .There are five different transmission chains of H1a subtype caused measles co-circulations in Ning-bo .

Objective: To analyze the epidemiological characteristics of coronavirus disease 2019 （COVID-19） cases reported in Ningbo from January 22 to February 22, 2020, so as to provide guidance for the prevention and control of the COVID-19 epidemic. Methods: The confirmed cases of COVID-19 reported by Ningbo were selected from National Diseases Prevention and Control Information System to analyze the epidemiological characteristics by descriptive epidemiological method, including time, spatial and population distribution, clinical symptoms and exposure history. Results: A total of 157 confirmed cases of COVID-19 were reported and there was no death. The first confirmed case was reported on January 22. On the incidence curve, the peak was from January 22 to February 4, with a maximum of 15 cases in a single day. The incidence curve presented sustained human-to-human transmission. The number of the cases showed a declining trend from February 5. The confirmed cases were reported in all 10 counties（cities or districts）,among which 69（43.95%）cases were reported in Haishu District. The confirmed cases were mainly 30-69 years old,accounting for 78.34%;were mainly farmers,household workers and retired people,accounting for 59.87%;and were mainly clinically mild,accounting for 87.90%.There were 51 imported cases, accounting for 32.48%. The initial confirmed case was a local case. In the early stage of the epidemic, local cases and imported cases prevalent together,which was due to the outbreak caused by the large-scale buddhist activity on January 19.This event resulted in 67 confirmed cases and 15 asymptomatic cases. There totally reported 22 clusters with 138 （87.90%）confirmed cases. Conclusions In the early stage of the COVID-19 epidemic in Ningbo, the imported cases and local cases prevalent at the same time. Most of the cases were female, aged from 30 to 69 years, and their occupation were farmers, household workers and retired people. With comprehensive measures taken, the epidemic of COVID-19 in Ningbo have been under control.

Objective:To analyze the epidemiological characteristics of reinfection of 2019-nCoV and influencing factors, and provide evidence for effective prevention and control of COVID-19 epidemic.Methods:The incidence data of COVID-19 in Ningbo from January 1, 2020 to November 30, 2022 were collected from the infectious disease surveillance system of Chinese information system for disease control and prevention. The incidence of reinfection of 2019-nCoV was investigated by using questionnaire. logistic regression analysis was used to analyze the influences of gender, age, time interval from the first infection, history of underlying disease, 2019-nCoV vaccination dose and disease severity on the reinfection.Results:A total of 897 previous 2019-nCoV infection cases were investigated, of which 115 experienced the reinfection of 2019-nCoV, the reinfection rate was 12.82%. The interval between the two infections M( Q1, Q3) was 1 052 (504, 1 056) days. Univariate analysis showed that age, 2019-nCoV vaccination dose, history of underlying disease, type of 2019-nCoV variant causing the first infection, time interval from the first infection and severity of the first infection were associated with the reinfection rate (all P<0.05). Multivariate logistic regression analysis showed that the risk for reinfection in age group 30- years was higher than that in age group ≥60 years ( OR=2.10, 95% CI: 1.11-3.97). No reinfection occurred in those with time interval from the first infection of <6 months, and the risk for reinfection was higher in those with the time interval of ≥12 months than in those with the time interval of 6- months ( OR=6.68, 95% CI: 3.46-12.90). The risk for reinfection was higher in the common or mild cases than in the asymptomatic cases ( OR=2.64, 95% CI: 1.18-5.88; OR=2.79, 95% CI: 1.27-6.11). Conclusion:The time interval from the first infection was an important influencing factor for the reinfection of 2019-nCoV, and the probability of the reinfection within 6 months was low.

Objective:To investigate the local epidemic of COVID-19 caused by 2019-nCoV Delta variant in Zhenhai district of Ningbo, identify the transmission chain and provide reference for the prevention and control of COVID-19 epidemic.Methods:The incidence data of COVID-19 in Zhenhai from 6 to 18 December, 2021 were collected in field investigation. Field epidemiological investigation was conducted to understand the epidemiological characteristics of COVID-19 cases and analyze the transmission chains.Results:The first case might be infected with 2019-nCoV through direct or indirect exposure when passing through a medium-risk area, then a family cluster was caused, and the epidemic spread through close contacts of family members with others such as work, daily life, and moxibustion. The epidemic lasted for 14 days, and 74 confirmed COVID-19 cases were reported. The median incubation period was 4.0(3.0,5.8)d. All the cases were in a chain of transmission for more than 6 generations, and the intergenerational interval was 3.5(2.0,5.3)d. The gene sequencing result indicated that the pathogen was Delta AY.4 variant of 2019-nCoV. Both the epidemiological investigation and the gene sequencing results supported that the local COVID-19 epidemic in Zhenhai was associated with the COVID-19 epidemic in Shanghai.Conclusions:The transmission chain of this epidemic was clear. Delta AY.4 variant has obvious characteristic to cause case clusters in families, places with poor ventilation, and residential communities. It is suggested to strengthen the health management in key areas and key populations, and increase the frequency of nucleic acid testing.

Objective: To study the infection rate of secondary close contacts of COVID-19 patients, and assess the infection risk in the contacts. Methods: COVID-19 patients' close contacts (with a clear exposure time to index case) with negative nucleic acid test results and secondary close contacts were surveyed in continuous isolation and medical observation in this prospective study. The dynamic nucleic acid test results of the close contacts and secondary contacts of COVID-19 patients were collected to assess their risk of infection. Results: A total of 4 533 close contacts were surveyed, in whom 14 were confirmed as COVID-19 patients with overall secondary attack rate of 0.31%, and 4 201 secondary contacts were tracked, in whom no subsequent infections occurred. Conclusion: Close contacts of COVID-19 patients entered in centralized isolation for medical observation with negative nucleic acid tese results,the secondary close contacts of COVID-19 patients have no risk of infection.
COVID-19/epidemiology* ; Contact Tracing ; Humans ; Incidence ; Nucleic Acids ; Prospective Studies ; SARS-CoV-2