Objective To evaluate the clinical application of 2000 ArthroCare System in knee arthroscopic surgery. Methods 221 cases of knee problems were treated with 2000ArthroCare System. The disorders of the 221 cases diagnosed by the arthroscopy were as follows: 73 cases of osteoarthritis, 49 meniscus tear, 29 degenerative cartilage injury, 11 plica synovitis, 11 Kaschin Beck disease, 8 ACL, 5 osteochondritis dissecans, and 2 TKA brisement. The operative procedures, such as meniscectomy, meniscoplasty, fitting of cartilage and ligament, synovectomy, and release of lateral patellar retinaculum, were done with 2000ArthroCare System and arthroscopy. Results The Lysholm Knee scores were 43.92 preoperatively, 81.96 three months postoperatively, and 92.06 six months postoperatively. Conclusion Knee problems can be effectively released with 2000 ArthroCare system vaporization under arthroscopic guidance. The advantages of this procedure are very limited tissue damage, mild reaction, less blood loss, early rehabilitation, and fine functional recovery.

Objective:To analyze the clinical characteristics and diagnosis and treatment of children with Kasabach-Merritt phenomenon (KMP).Methods:A retrospective analysis was conducted on the clinical data and follow-up data of 8 patients diagnosed KMP in Beijing Children′s Hospital, Capital Medical University from January 2016 to January 2019.The clinical data included laboratory examination, diagnosis, treatment and prognosis.Results:Among the 8 children with KMP, 6 cases were male and 2 cases were female.The median onset age was 4 (0-17) months, 2 cases of neonatal onset.The median onset to the diagnosis time was 59 (34-140) days; 6 cases with bone destruction; 6 cases had misdiagnosis and mistreatment history, they were misdiagnosed as idiopathic thrombocytopenic purpura, Evans syndrome, abnormal bone and joint development; 4 cases were Kaposiform hemangioendothelioma; 8 cases were used alone or combined with the application of hormones, Sirolimus, and Vincristine, 7 patients underwent interventional therapy.All patients survived with a median follow-up period of 487 (112-1 033) days.Median time of platelet count returned to normal was 24.5 (7-60) days, and median time of fibrinogen returned to normal was 20 (7-30) days.Median time of D-dimer dropped to a normal was 105 (40-240) days.Conclusions:Children with concurrent platelet count and coagulation abnormalities should be considered with KMP.Doctors need to identify the potential visceral vascular lesions.Early diagnosis and treatment are important, which can improve the clinical prognosis of patients.

Objective To explore the clinical features and points of diagnosis and treatment for congenital thrombotic thrombocytopenic purpura (TTP) in children.Methods The clinical manifestations,laboratory tests,genetic analysis and treatments of 5 children with congenital TIP hospitalized in Beijing Children's Hospital,Capital Medical University from February 2015 to July 2017 were analyzed retrospectively.Results Among the 5 children with congenital TTP diagnosed by genetic monitoring and enzymology,there were 1 male and 4 females,3 cases had suspicious positive family history,the age of onset was several hours after birth (range several hours after birth to 28 months).The main clinical manifestations were recurrent moderate to severe thrombocytopenia in 5 cases,mild to moderate hemolytic anemia in 4 cases,proteinuria or hematuria in 2 cases,and nervous system involvement in 1 case.The recurrence time was 1.5 (range 1.0 to 5.0) times per year and most of the inducing factors were respiratory and (or) digestive tract infections.Laboratory test showed that ADMATS13 enzyme activity were 0 in 4 cases,the enzyme activity was 100％ in 1 case due to plasma infusion before examination.ADMATS13 enzyme antibody detection of all 5 cases were negative.Genetic analysis of all 5 children showed complex heterozygous mutations at different loci of ADAMTS13 gene,among which 8 loci were previously unreported,details are as follows:missense mutations in 4 cases (c.1564T＞C(p.522C＞R),c.1510G＞T(p.504D＞Y),c.4154A＞C (p.1385Q＞P) and c.G3854C (P.R1285P));frameshifi mutations in 3 cases(c.2875_2876insT (p.959Lfs29),c.2362_2363delGG (p.788G＞Gfs56) and c.1335delC (p.F445fs)),shear mutation in one case(IVS21 + 1A＞G).The patients in the acute phase were all treated with fresh frozen plasma infusion (10 ml/(kg· d)),continuous application for 7-14 days).Platelets gradually returned to normal and clinical symptoms improved.The follow-up time was 27 months (range 11-35 months).All the children survived,among whom 2 cases were treated with prophylaxis and monitoring platelet stability above 200×109/L,3 cases were treated on-demand only when platelet decreased and monitoring platelet stability above 100× 109/L.Conclusions The main clinical manifestation of congenital TTP is recurrent thrombocytopenia with or without hemolytic anemia.The key point of treatment is plasma infusion.Genetic testing is helpful for early diagnosis.

Objective: To know the detection rate of hereditary thrombocytopenia (HT) in children with chronic thrombocytopenia and its clinical and laboratory characteristics for an early clinical identification and diagnosis of HT in future. Methods: Data of the children with thrombocytopenia, who had been treated in Beijing Children′s Hospital from April 2016 to May 2018 and whose present history lasted for more than 1 year and had poor response to immunotherapy were retrospectively collected.HT was screened in these patients by adopting next generation sequencing (NGS). Finally, clinical and laboratory characteristics of these children with HT were summarized and analyzed. Results: A total of 161 children with chronic thrombocytopenia were included.Forty-three cases (26.7%) were found to have gene mutations.The genetic rules of the mutant gene, the family verification and the clinical manifestations of the proband and some related laboratory tests were analyzed and 24 cases (14.9%) can be diagnosed as HT.Among the HT patients, the proportion of males and females was 159, and the median onset of age was 0.58 years, which was significantly lower than that of non-HT cases (the median onset of age was 4.36 years), and the difference was statistically significant (P<0.001); the proportion of mucosal hemorrhage and visceral hemorrhage (31.8% and 13.7%) of HT was significantly higher than non-HT cases (15.3% and 0.6%), and the difference was statistically significant (P<0.001). Fifty percent of (12/24 cases) cases of HT had positive family history; according to the ave-rage platelet volume and platelet morphology in peripheral blood smear, HT could be divided into small platelet HT, po-sitive platelet HT and large platelet HT.Some cases had well response to immunotherapy but seemed easy to relapse du-ring the withdrawal period, while the others responded poorly to therapy.Different clinical manifestations of HT suggest different pathogenesis, which can be divided into the related types of megakaryocyte differentiation defect, megakaryocyte maturation defect, platelet release defect and platelet survival time shortening. Conclusions The pathogenesis and cli-nical phenotype of HT was different.Some of them were effective for immunotherapy, which were easily confused with immune thrombocy-topenla(ITP). It is clinically necessary to perform NGS in children with thrombocytopenia at early onset, abnormal platelet morphology, prolonged disease course or severe mucosal/visceral hemorrhage, in order to recognize HT timely to avoid delay in diagnosis and poor prognosis.

Objective:To analyze expression and models of CD39,CTLA-4,and PD-1 on T cells,to investigate effect of cyclic adenosine monophosphate(cAMP)on their expressions,and to analyze key pathways regulating their expressions.Methods:Small molecules such as adenylate cyclase(ACs)activators,phosphodiesterase(PDE)inhibitors,protein kinase A(PKA)inhibitors and PKA-CREB inhibitors were used to stimulate rhesus macaque peripheral blood mononuclear cells in vitro,and changes in ratios of CD39,CTLA-4,and PD-1 positive(CD39+,CTLA-4+,and PD-1+)T cells were detected by flow cytometry,and to analyze their expression patterns,and effects of small molecules on ratio of positively expressing/co-expressing cells were compared to clarify expres-sion patterns and molecules and pathways that regulated expression.Results:Normal macaque CD4+T and CD8+T cells had low ratios of CD39+,CTLA-4+,and PD-1+cells,and positive cells predominantly expressed only one of these molecules.Increasing intracellular cAMP levels did not affect CD39+T cell ratio,significantly increased CTLA-4+T cell ratio,and decreased PD-1+CD8+T cell ratio,involving cell populations with mono expression of CTLA-4 and PD-1.Inhibition of PKA activity reduced potentiation of CTLA-4 expression by broad-spectrum PDE inhibitor,3-isobutyl-1-methylxanthine(IBMX),but did not affect PD-1 expression.Exchange protein activated by cAMP did not affect CTLA-4 expression but downregulate PD-1+CD4+/CD8+T cells ratio.Upregulation of CTLA-4 by PDE4B selective inhibitors was similar to IBMX,while regulation of PDE3 and PDE5A selective inhibitors on PD-1 expression was similar to IBMX.Conclusion:CD39,CTLA-4 and PD-1 have different expression models on T cells but are differentially regulated by cAMP levels and have different cAMP downstream signal pathways involved in expression regulation.