[Comprehensive assessment of mismatch repair and microsatellite instability status in molecular classification of endometrial carcinoma]

Objective: To explore the concordance and causes of different mismatch repair (MMR) and microsatellite instability (MSI) detection results in endometrial carcinoma (EC) molecular typing. Methods: A total of 214 EC patients diagnosed from January 2021 to April 2023 were selected at the Department of Pathology, Peking University Third Hospital. The immunohistochemistry (IHC) results of MMR protein were reviewed. Tumor specific somatic mutations, MMR germline mutations, microsatellite scores and tumor mutation burden (TMB) were detected by next-generation sequencing (NGS) with multi-gene panel. Methylation-specific PCR was used to detect the methylation status of MLH1 gene promoter in cases with deficient MLH1 protein expression. In cases with discrepant results between MMR-IHC and MSI-NGS, the MSI status was detected again by PCR (MSI-PCR), and the molecular typing was determined by combining the results of TMB and MLH1 gene promoter methylation. Results: (1) In this study, there were 22 cases of POLE gene mutation subtype, 55 cases of mismatch repair deficient (MMR-d) subtype, 29 cases of p53 abnormal subtype, and 108 cases of no specific molecular profile (NSMP). The median age at diagnosis of MMR-d subtype (54 years old) and the proportion of aggressive histological types (40.0%, 22/55) were higher than those of NSMP subtype [50 years old and 12.0% (13/108) respectively; all P<0.05]. (2) Among 214 patients, MMR-IHC test showed that 153 patients were mismatch repair proficient (MMR-p), 49 patients were MMR-d, and 12 patients were difficult to evaluate directly. MSI-NGS showed that 164 patients were microsatellite stable (MSS; equal to MMR-p), 48 patients were high microsatellite instability (MSI-H; equal to MMR-d), and 2 patients had no MSI-NGS results because the effective sequencing depth did not meet the quality control. The overall concordance between MMR-IHC and MSI-NGS was 94.3% (200/212). All the 12 discrepant cases were MMR-d or subclonal loss of MMR protein by IHC, but MSS by NGS. Among them, 10 cases were loss or subclonal loss of MLH1 and (or) PMS2 protein. Three discrepant cases were classified as POLE gene mutation subtype. In the remaining 9 cases, 5 cases and 3 cases were confirmed as MSI-H and low microsatellite instability (MSI-L) respectively by MSI-PCR, 6 cases were detected as MLH1 gene promoter methylation and 7 cases demonstrated high TMB (>10 mutations/Mb). These 9 cases were classified as MMR-d EC. (3) Lynch syndrome was diagnosed in 27.3% (15/55) of all 55 MMR-d EC cases, and the TMB of EC with MSH2 and (or) MSH6 protein loss or associated with Lynch syndrome [(71.0±26.2) and (71.5±20.1) mutations/Mb respectively] were significantly higher than those of EC with MLH1 and (or) PMS2 loss or sporadic MMR-d EC [(38.2±19.1) and (41.9±24.3) mutations/Mb respectively, all P<0.01]. The top 10 most frequently mutated genes in MMR-d EC were PTEN (85.5%, 47/55), ARID1A (80.0%, 44/55), PIK3CA (69.1%, 38/55), KMT2B (60.0%, 33/55), CTCF (45.5%, 25/55), RNF43 (40.0%, 22/55), KRAS (36.4%, 20/55), CREBBP (34.5%, 19/55), LRP1B (32.7%, 18/55) and BRCA2 (32.7%, 18/55). Concurrent PTEN, ARID1A and PIK3CA gene mutations were found in 50.9% (28/55) of MMR-d EC patients. Conclusions: The concordance of MMR-IHC and MSI-NGS in EC is relatively high.The discordance in a few MMR-d EC are mostly found in cases with MLH1 and (or) PMS2 protein loss or MMR protein subclonal staining caused by MLH1 gene promoter hypermethylation. In order to provide accurate molecular typing for EC patients, MLH1 gene methylation, MSI-PCR, MMR gene germline mutation and TMB should be combined to comprehensively evaluate MMR and MSI status.

[Effect of acupuncture on intestinal flora and TLR4 in brain and intestinal tissues in rats with stress gastric ulcer]

OBJECTIVE

To observe the effect of acupuncture at "Guanyuan" (CV 4) and "Xiajuxu" (ST 39) on intestinal flora and Toll-like receptors-4 (TLR4) in brain and intestinal tissue in rats with stress gastric ulcer (SGU), and to explore the possible mechanism of acupuncture for SGU.

METHODS

Thirty-one male SD rats were randomly divided into a blank group (n=7), a model group (n=8), an acupuncture group (n=8) and a drug group (n=8). The rats in the model group, acupuncture group and drug group were treated with modified restraint plus water-immersion stress method to establish SGU model. After modeling, the rats in the acupuncture group were treated with acupuncture at "Guanyuan" (CV 4) and "Xiajuxu" (ST 39), 20 min each time, and the needles were twirled for 30 s every 5 min. The rats in the drug group were treated with intragastric administration of 2 mL omeprazole enteric-coated tablets (20 mg/mL). Both the treatments were given once a day for 5 days. After the intervention, the gastric mucosal damage index was calculated by Guth method; the morphological changes of gastric mucosa were observed by HE staining; the diversity of intestinal flora was detected by 16S rDNA high-throughput sequencing; TLR4 contents in brain and intestinal tissues were determined by ELISA.

RESULTS

Compared with the blank group, the gastric mucosal damage index was significantly increased in the model group (P<0.01); the morphological changes of gastric mucosa were obvious; the Observed Species index and Shannon index of α diversity index of intestinal flora were decreased (P<0.05); the β diversity showed that the spatial distance between the model group and the blank group was far; the TLR4 contents in the brain and intestinal tissue were increased (P<0.05, P<0.01). Compared with the model group, the gastric mucosal damage index was decreased in the acupuncture group and the drug group (P<0.05); the morphology of gastric mucosa was improved; the Observed Species index and Shannon index of α diversity index of intestinal flora in the acupuncture group was increased (P<0.05), and the Shannon index in the drug group was increased (P<0.05); the β diversity showed that the spatial distance between the acupuncture group and the blank group was close; the TLR4 contents in the brain and intestinal tissues of the acupuncture group were decreased (P<0.01). Compared with the drug group, the contents of TLR4 in the intestinal tissue of the acupuncture group were decreased (P<0.05).

CONCLUSION

Acupuncture at "Guanyuan" (CV 4) and "Xiajuxu" (ST 39) could alleviate SGU in rats, and its mechanism may be related to increasing the diversity of intestinal flora, promoting the disorder of intestinal flora to normal, and reducing the overexpression of TLR4 in brain and intestinal tissues.

Chemistry course network teaching based on key information search and big data cloud platform

At present, the theoretical and experimental teaching parts of chemistry teaching are difficult to present through online teaching, and the teaching effect is difficult to effectively improve. In order to improve the effect of online teaching of chemistry courses and discover the problems in teaching in a timely and effective manner, this paper builds the corresponding teaching system, optimizes the performance of the system with key information search and big data cloud platform, improves the data mining ability and data analysis ability, and improves the system running speed. Moreover, this article constructs functional modules according to the actual needs of chemistry course network teaching and constructs sub-modules for functional modules. The constructed model can be displayed in the form of a webpage, and the model has the ability of data mining and problem analysis of chemistry course network teaching. In addition, in order to verify the effect of the model, this paper designs experiments to analyze its performance. The research results show that the system constructed in this paper has good performance.

[Study on pathogenicity of Pneumocystis and its association with development of chronic obstructive pulmonary disease]

OBJECTIVE

To investigate the pathogenicity of Pneumocystis and its association with the development of chronic obstructive pulmonary disease (COPD).

METHODS

The rat model of Pneumocystis pneumonia (PCP) was induced by intraperitoneal injection with dexamethasone, which was confirmed by pathogenic detection. The pathologic changes of rat lung specimens were examined using conventional HE staining, and the expression of inflammatory cells were detected by flow cytometry in bron-choalveolar lavage fluid (BALF) and splenic tissues of the rat model of PCP. In addition, the serum levels of matrix metalloproteinase 8 (MMP-8) and MMP-9 were measured using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Fusion and atrophy of alveolar spaces and hyperplasia of lung tissue were seen in the lung specimens of the rat model of PCP, and foam-like alveolar exudates and infiltration of inflammation cells were observed in the alveolar space, while severe infections exhibited consolidation of lung, which was similar to pathological features of COPD. The counts of CD8⁺ T lymphocytes (t = -7.920 and -12.514, P < 0.01), macrophages (t = -7.651 and -14.590, P < 0.01) and granulocytes (t = -10.310 and -16.578, P < 0.01) significantly increased and the counts of CD4⁺ T lymphocytes (t = 6.427 and 18.579, P < 0.01) significantly reduced in the BALF and splenic specimens of the rats with PCP relative to those without PCP. In addition, higher serum MMP-8 (t = -8.689, P < 0.01) and MMP-9 levels (t = -7.041, P < 0.01) were measured in rats with PCP than in those without PCP.

CONCLUSIONS

Pneumocystis infection may be associated with the development and progression of COPD.

[Primary culture of cat intestinal epithelial cell and construction of its cDNA library]

Objective To establish the primary cat intestinal epithelial cells (IECs) culture methods and construct the cDNA library for the following yeast two-hybrid experiment, so as to screen the virulence interaction factors among the final host. Methods The primary cat IECs were cultured by the tissue cultivation and combined digestion with collagenase XI and dispase I separately. Then the cat IECs cultured was identified with the morphological observation and cyto-keratin detection, by using goat anti-cyto-keratin monoclonal antibodies. The mRNA of cat IECs was isolated and used as the template to synthesize the first strand cDNA by SMART™ technology, and then the double-strand cDNAs were acquired by LD-PCR, which were subsequently cloned into the plasmid PGADT7-Rec to construct yeast two-hybrid cDNA library in the yeast strain Y187 by homologous recombination. Matchmaker™ Insert Check PCR was used to detect the size distribution of cDNA fragments after the capacity calculation of the cDNA library. Results The comparison of the two cultivation methods indicated that the combined digestion of collagenase XI and dispase I was more effective than the tissue cultivation. The cat IECs system of continuous culture was established and the cat IECs with high purity were harvested for constructing the yeast two-hybrid cDNA library. The library contained 1.1×10⁶ independent clones. The titer was 2.8×10⁹ cfu/ml. The size of inserted fragments was among 0.5-2.0 kb. Conclusion The yeast two-hybrid cDNA library of cat IECs meets the requirements of further screen research, and this study lays the foundation of screening the Toxoplasma gondii virulence interaction factors among the cDNA libraries of its final hosts.