Objective: To investigate the clinicopathologic features of microcystic, elongated and fragmented (MELF) pattern invasion of endometrial adenocarcinoma. Methods: HE and immunohistochemistry staining method were used to analysis morphologic features and immunophenotype of 72 patients of endometrial adenocarcinoma with MELF pattern invasion, and chi-square test was used to analysis the clinicopathologic features. Results: The mean age of 72 patients was 54 years (40 to 70 years). Thirty-two patients were pre-menopausal and 40 were post-menopausal. According to the FIGO staging system (2014), 32 cases(44.4%)were at stage Ⅰ, 22 cases(30.6%)at stage Ⅱ, 17 cases(23.6%)at stage Ⅲ and 1 case(1.4%) at stage Ⅳ. Microscopically, MELF invasion showed microcystic, elongated slit-like or fragmented glands in myometrium and their lining cells usually were cube or flat, as well as the single or clusters of eosinophilic tumor cells mimicking histocytes. In addition, a fibromyxoid or inflammatory stromal response was often present.Immunohistochemical staining showed that MELF invasion was positive for p16, CA125 and CA19-9, but negative for ER, PR and p53.Compared with non-MELF pattern invasion, significant differences were noted in menopause pausimenia, FIGO stages, deep invasion into myometrium, lymph metastasis, lymphovascular space invasion (LVSL), serum CA125 and CA19-9 in patients with MELF pattern invasion (all P<0.05). Conclusions MELF pattern invasion of endometrial adenocarcinoma is characterized by advanced FIGO stage, deep myoinvasion, high metastasis rate to lymph node and LVSL. Pathologists should recognize the MELF invasion and evaluate the depth of myometrium of infiltration and LVSL with special attention to the presence of MELF invasion with necessary immunohistochemistry for more accurate pathological diagnosis.

Objective:To investigate the infection rate in close contacts of COVID-19 patients before and after the last negative nucleic acid test, evaluate the effect of dynamic nucleic acid test in determining the infectivity of COVID-19 patients.Methods:Dynamic nucleic acid test results of COVID-19 cases were collected in a retrospective cohort study. COVID-19 cases with negative nucleic acid test results before their first positive nucleic acid tests were selected as study subjects. Close contacts of the index cases and the secondary close contacts were kept isolation for medical observation to assess their risk of infection.Results:This study included 89 confirmed cases from two local COVID-19 epidemics in Ningbo. A total of 5 609 close contacts were surveyed, the overall infection rate was 0.20%. No close contacts of the COVID-19 cases before the last negative nucleic acid test were infected, and the infection rate in the close contacts of the COVID-19 cases after the last negative nucleic acid test was 1.33%, all of these close contacts lived together with the index cases. No secondary close contacts were infected.Conclusion:COVID-19 patient becomes infectious after the last nucleic acid is negative, and has no infectivity before the last nucleic acid negative.

Objective To explore the residual level of FPMs in indoor dust samples in Shenzhen from 2020 and 2021, and to analyze its temporal distribution characteristics. Methods In the present study, indoor dust samples (n=193) from residential buildings in Shenzhen. were collected to analyze the temporal variation characteristics of FPMs. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was applied to determine the concentrations of FP and its four major metabolites (fipronil-sulfone, fipronil-sulfide, fipronil-desulfinyl, and fipronil-amide; abbreviated as FP-SFO, FP-SFI, FP-DES, and FP-AM) in the samples. The sum of the concentrations of FP and its four metabolites was represented as additive mass concentration (ΣFPMs). Additionaly, Wilcoxon test was performed to determine the temporal distribution differences of FPMs’ concentrations. Results From 2020 to 2021, the concentration of ΣFPMs for the in door dust samples in Shenzhen ranged from 0.51 to 4 415 ng/g (median: 18.8ng/g). FP, FP-SFO AND FP-SFI were the major target analytes in the sample with detection rates of 90.60%，86.20% and 75.40%, respectively. The detection rates of other metabolites were low (≤ 44.3%). Analysis of the temporal variation trend of FPMs’ concentrations showed that there was no significant difference in the levels of ΣFPMs between warm season（spring and summer）and cold season（autumn and winter）in the indoor dust samples from 2020 to 2021(2.38 vs 2.84ng/g , P > 0.05). However , the concentrations of FP-SFI and ΣFPMs in the indoor dust samples collected from 2021 showed an significantly increasing trend compared with 2020（1.02 vs 1.89 , 17.80vs. 20.10 ng/g , P < 0.05). Conclusion From 2020 to 2021 , the detection level of FPMs in indoor dust in Shenzhen is relatively high and shows an upward trend , with no obvious seasonal difference. However, whether the residual level of FPMs in indoor dust poses a risk to human health needs further study.

Objective    To analyze the surgical efficacy and influencing factors of myasthenia gravis (MG) patients with thymic atrophy after thymectomy. Methods    The clinical data of MG patients with thymic atrophy undergoing thymectomy between October 2014 and May 2018 in Daping Hospital of Army Medical University and Shijiazhuang People Hospital were retrospectively analyzed. Results    A total of 71 patients were collected, including 40 males and 31 females with a mean age of 45.17±12.42 years. All patients received the surgery successfully. After the surgery, 20 (28.17%) patients were stable remission, 12 (16.90%) patients were minimal manifestation status,19 (26.76%) patients were improved, 5 (7.04%) patients showed no change, 3 (4.23%) patients were worsened, 10 (14.08%) patients were exacerbated and 2 (2.82%) patients were dead. Multivariate logistic regression analysis showed that the preoperative illness duration (OR=4.61, 95%CI 1.13-18.85, P=0.03), and postoperative pyridostigmine combined with immunosuppressive (OR=0.12, 95%CI 0.03-0.45, P=0.00) were independent risk factors for long-term efficacy of thymectomy for MG patients with thymic atrophy. Conclusion    Early surgery after diagnosis of MG and postoperative pyridostigmine combined with immunosuppressive treatment is beneficial to the prognosis of MG patients with thymic atrophy.