Objective:To investigate the prevalence of norovirus and the correlation between norovirus infection and stool traits and clinical symptoms in children with acute gastroenteritis during 2021-2022.Method:A total of 2 195 anal swab samples were collected from cases of acute gastroenteritis in Beijing Children 's Hospital Affiliated to Capital Medical University from January 2021 to December 2022. PCR fluorescent probe assay was performed to detect norovirus，the clinical information and test results were performed by statistical analysis. Results:The detection rate of norovirus was 19.09%（419/2 195）in 2 195 children. The detection rates of male and female were 17.80%（244/1 371）and 21.24%（175/824），respectively，with statistically significant differences between genders（ χ2=3.945, P<0.05）. The positivity rate of noroviruses was higher in aged 1 month to 3 years［29.09%（64/220）~40.69%（94/231）］，especially in 1 year［40.69%（94/231）］. The norovirus detection rate ranged from 2.44%（2/82）to 35.84%（62/173）in different months，with a high detection rate between January and March，higher in the winter and spring［28.36%（150/529），21.07%（146/693）］，showing a clear seasonal distribution.Clinical symptoms of both vomiting and diarrhea were significantly more common among norovirus positive than negative children，the difference was statistically significant（ χ2=57.29, P<0.05）. Conclusion:In the high incidence season of winter and spring，for infants and young children aged 1 month to 3 years with diarrhea accompanied by vomiting symptoms，especially those aged 1 year，it is recommended to undergo norovirus related testing in time. Early treatment and isolation measures should be taken for diagnosed children to reduce cross infection and prevent outbreaks.

To explore the effect of adipose-derived mesenchymal stem cells (ADMSCs) on ovarian damage induced by cyclophosphamide (CTX) and its mechanism.
 Methods: ADMSCs isolated from adipose tissue of female SD rats were cultured and divided into a blank group and a CTX group (n=15 in each group). CTX (75 mg/kg) was injected intraperitoneally to establish a model of ovarian damage in rats. A total of 45 female SD rats were also divided into 3 groups: Group A (15 rats, only injected intraperitoneally with 75 mg/kg CTX diluted with 1 mL 0.9% saline), Group B [15 rats, injected intraperitoneally with 75 mg/kg CTX diluted with 1 mL 0.9% saline, after 4 estrus cycles, injected 0.6 mL ADMSCs (6×105 cells) by the tail vein], and Group C [15 rats, injected intraperitoneally with 75 mg/kg CTX diluted with 1 mL 0.9% saline, after 4 estrus cycles, injected 40 mL ADMSCs (20 mL per side, 2×104 cells) in situ ovarian]. After 4 estrus cycles, the changes of quality of life, ponderal growth were recorded, the sex hormone levels [estradiol (E2), follicle-stimulating hormone (FSH)] were tested by ELISA, and the morphology of ovarian tissue and follicle count were observed by HE staining. The expression of BMP-15, Bcl-2 and Bax in ovarian tissues were tested by immunohistochemistry, real-time PCR or Western blotting. The apoptosis rate of follicular cells was detected by TdT-mediated dUTP nick end labeling (TUNEL) assay.
 Results: After transplantation of ADMSCs, compared with the Group A, their quality of life of rats in the Group B and C was improved, and the ponderal growth was increased (both P<0.01). Compared with the Group A, the serum E2 levels in the Group B and the Group C were increased (P<0.01, P<0.05), and the FSH levels in the Group B and C were decreased (both P<0.01). The granular cell layer, the number of corpus lutein and the count of various grade follicles were significantly increased, and many new follicles and mature oocytes were observed in the Group B and C. Compared with Group A, the count of primitive follicles, sinusoidal follicles, pre-ovulation follicles and total follicles, and pre-sinusoidal follicles were dramatically increased in the Group B. The follicle at all levels count was increased in the Group C than that in the Group A (all P<0.01). Comparing with the Group A, the expressions of BMP-15 and Bcl-2 were increased (all P<0.01), the expressions of Bax was decreased (both P<0.01), and the apoptosis rates of follicular cells were decreased in the Group B and C (both P<0.01). However, there was no difference between the Group B and the Group C in the above indexes (all P>0.05).
 Conclusion: ADMSCs transplantation can effectively repair ovarian damage induced by CTX in rats, which may be achieved by inhibiting mitochondrial apoptosis of granulosa cells.
Animals ; Cyclophosphamide ; Female ; Mesenchymal Stem Cells ; Ovary ; Quality of Life ; Rats ; Rats, Sprague-Dawley