Viral myocarditis is a myocardial disease resulting from various viral infections.Due to the com-plexity of its pathogenesis,effective prevention and treatment options are currently lacking.Establishing appropriate ex-perimental models is crucial for studying the pathogenic mechanisms,disease progression,early diagnosis,and the devel-opment of new drugs and therapies for viral myocarditis.This article reviews the construction methods,research advance-ments,and applications of common experimental models of viral myocarditis,which range from cell models to small ani-mal models,including mice,hamsters,and rabbits,as well as larger animals such as pigs and non-human primates.Ad-ditionally,we summarize and discuss future research directions,providing a theoretical foundation and technological guid-ance for the prevention and treatment of viral myocarditis in clinical settings.

Viral myocarditis is a myocardial disease resulting from various viral infections.Due to the com-plexity of its pathogenesis,effective prevention and treatment options are currently lacking.Establishing appropriate ex-perimental models is crucial for studying the pathogenic mechanisms,disease progression,early diagnosis,and the devel-opment of new drugs and therapies for viral myocarditis.This article reviews the construction methods,research advance-ments,and applications of common experimental models of viral myocarditis,which range from cell models to small ani-mal models,including mice,hamsters,and rabbits,as well as larger animals such as pigs and non-human primates.Ad-ditionally,we summarize and discuss future research directions,providing a theoretical foundation and technological guid-ance for the prevention and treatment of viral myocarditis in clinical settings.

Objective:To investigate the application value and treatment opportunity of single balloon enteroscopy in children with Peutz-Jeghers syndrome(PJS).Methods:A retrospective analysis was conducted on 33 children diagnosed with PJS in Hunan Children′s Hospital from January 2011 to September 2021.The patient′s age, gender, family history, clinical symptoms, enteroscopy examination and treatment, number of polyps, intraoperative and pos-toperative complications, surgical treatment, recurrence of surgery, and follow-up data were analyzed, and the chi- square test was used for statistical analysis. Results:A total of 33 PJS children aged (9.00±3.13) years, including 21 males and 12 females, were included.All of them received at least once single balloon enteroscopy test.The main manifestations of the children were black spots (33 cases) and multiple polyps in the digestive tract (31 cases). In all the 33 cases, black spots were distributed on lips.Some black spots were also found at the end of fingers (3 cases), at the end of foot toes(2 cases), and at the end of finger toes (6 cases). During the operation, 391 polyps were removed, most of which were jejunum polyps (37.08%, 145/391 polyps). Eleven children with PJS has intussusception, of which intestinal intussusception accounted for 90.91% (10/11 cases). Ten cases (30.30%, 10/33 cases) received surgical treatment, and 72.73% (8/11 cases) underwent surgery for acute refractory intussusception.One case had intestinal perforation and 2 cases were bleeding during the operation, and the 3 cases recovered completely after hemostatic clip sealing and surgical treatment.The incidence of hollow ileum polyps and giant polyps in children aged >8 years was higher than that in children aged ≤8 years[92.55% (149/161 polyps) vs.7.45%(12/161 polyps), 96.20%(76/79 polyps) vs.3.80% (3/79 polyps)]. The differences were statistically significant ( χ2=9.854, 8.711, all P<0.05). There was no significant difference in the incidence of intussusception among different age groups ( P>0.05). Among the 33 children with PJS, 57.58% (19/33 cases) had recurrence 1-3 years after operation, and no cases of cancer have been followed up so far. Conclusions:Intestinal polyps are common in children with PJS, and the application of single-balloon enteroscopy in children with PJS is reliable and safe.Children over 8 years old are more vulnerable to empty ileum polyps and giant polyps.Therefore, it is advised that children aged above 8 years with PJS should undergo at least once enteroscopy.

Gastrointestinal bleeding is a clinical medical emergency and complicated etiology. The main clinical manifestations are hemoptysis, black stool, anemia of unknown cause, such as acute hemor￣rhage,if not promptly treated,there may be acute shock or even death. Acute gastrointestinal haemorrhage is a clinical critical disease. When the patient has active bleeding,the drug alone can not achieve the hemostatic effect. If the patient is not treated with timely and effective endoscopic therapy,their lives will be seriously threatened. Endoscopic examination can be used to diagnose and treat gastrointestinal bleeding,which is sim￣ple and convenient,with small trauma,quick effect and other advantages. With the development of endoscopic technique,the rate of operation and mortality of gastrointestinal hemorrhage decreased significantly.

With the overuse of antibiotics,Clostridium difficile infections are increasing,and the incidence of refractory or recurrent cases increase.Increasing resistance to the traditional treatment(metronidazole and/or vancomycin),relapsing Clostridium difficile infection needs to seek new treatments.Fecal microbiota transplantation has been widely used in the treatment of adult Clostridium difficile infection,but is seldom used in children.In this paper,fecal microbiota transplantation for the treatment of Clostridium difficile infection in children related issues were reviewed.

Enteral nutrition (EN) therapy is one of the most important treatments of Crohn's disease (CD),especially in European countries,EN is considered as the first-line of treatment for pediatric CD.EN can improve the poor nutrition condition,induction and maintenance remission,the risk of this treatment is very low.But in our country the application of EN is still limited,deepening the understanding and obtained clinical guidelines are very important.

The development of digestive endoscopy has played a very important role in promoting diagnosis and treatment for digestive system diseases in children. Electronic endoscopy is safe and simple for check and treatment. If applied to chronic diarrhea it will extensively improve the diagnosis and therapy efficacy.

Recently, the incidence of pediatric inflammatory bowel disease( IBD) is increasing. The diagnosis and treatment of IBD were focused by pediatric clinicians. The clinical features and treatment of pediatric IBD are dif-ferent,because of the growth and development. Growth deficiency and delayed puberty are unique symptoms. Children with IBD were treated with exclusive enteral nutrition as the first line treatment. The better treatment was formulated in accordance with the clinical features and nutritional therapy of pediatric IBD.

Objective To assess nutritional risks in children with allergic proctocolitis induced by cow milk protein,and to observe the effects of the feeding strategies for them with different interventions in feeding,and then to identify the best time and the best way to modify feeding strategies according to different individual.Methods The effectiveness of different feeding interventions was retrospectively analyzed after 2 weeks in 171 cases with allergic proctocolitis induced by cow milk protein in Hunan Children's Hospital during the period of Jan.2012 to Jul.2013.Thirty-two cases received breast feeding (18.7％) and 139 cases received non-breast feeding (81.3％).Intervention methods:32cases with breast feeding received the same feeding method;among 139 babies with non-breast feeding group,36 were plus free amino acid (AAF) (21.1％),and 103 were plus the extensively hydrolyzed formula (eHF).The intervention formula changes were observed in 8,12 and 24 weeks,respectively,and nutritional risks in 0,3,6 months were assessed,respectively.Results There were 171 patients totally,male to female ratio was 1.5 to 1.0,and the average age was (4.1 ± 1.3) months.After 2 weeks,147 cases were notably effective,accounting for 86％,and in the breast feeding group 79.2％ of the patients were notably effective,and there was no significance compared with the AAF group and eHF group (P ＞ 0.05).The intervention formulation changes during the following 6 months were as follows:in 8 weeks,30 cases in the breast feeding group breastfeeding continued,2 cases turned to eHF feeding for the lack of breast milk,21 cases were fed with AAF (12.3％),85 cases with eHF (49.7％),and 35 cases with moderately hydrolyzed formula (20.5％) ;in 12 weeks:23 cases had breast feeding (13.5％),16 cases were fed with free amino acid formula powder (9.4％),56 cases with extensively hydrolyzed formula (32.7％),and 76 cases with moderately hydrolyzed formula (44.4％) ;in 24 weeks:21 cases (12.3％) had breast feeding,7 cases were fed with AAF(4.1％),13 cases with moderately hydrolyzed formula(7.6％),and 130 cases with normal formula(76.0％).The mean levels of the nutritional risks were assessed according to STAMP in 0,3,6 months respectively:breast feeding group [(1.69 ± 0.78) scores,(1.50 ± 0.88) scores,(1.53 ± 0.67) scores,P ＞ 0.05] ; AAF group [(1.72 ± 0.78) scores,(1.53 ± 0.88) scores,(1.53 ± 0.65) scores,P ＞ 0.05] ; eHF group [(1.80 ± 0.69) scores,(1.68 ± 0.68) scores,(1.66 ± 0.65) scores,P ＞ 0.05].Conclusions The nutrition risk levels in children with milk protein allergic proctocolitis are low,and different feeding interventions according to tolerance had no impact on the nutritional status ; Breast feeding could effectively avoid cow milk allergy,and symptoms of the children with allergic proctocolitis would be relieved after 2-week intervention,and more than half of children could gain part of immune tolerance after intervention for 3 months or more,so for the children with allergic proctocolitis induced by cow milk protein,routine formula feeding should be stopped after 3 months,and individualized feeding intervention can be carried out according to immune tolerance to relieve the financial burden.