Objective:To explore the molecular mechanism for bone mass loss caused by staphylococcus aureus infection.Methods:Thirty 8-week-old male C57BL/6 mice were randomly divided into 3 groups ( n=10): control, infection and infection+JAK inhibitor (JAKi) ones. The mice were killed 2 weeks later for sampling from the femur and tibia. Micro-CT reconstruction was performed for analyses of BV/TV, Tb.N, Tb.Th and Tb.Sp to detect changes in bone mass; OCN immunohistochemistry and Goldner's trichrome staining were used to quantify osteoblasts; TRAP staining was used to quantify osteoclasts; the GSE166522 data set was downloaded and analyzed to explore the relationships between staphylococcus aureus infection and bone cell senescence and JAK/STAT pathway. Senescence β-Galactosidase staining, Osterix and P16 immunofluorescence colocalization were used to observe the changes in number of senescent cells. Results:MicroCT results showed a statistically significant difference in the loss of cancellous bone in the target area in the infection group compared with the control group ( P<0.05). The results of osteocalcin immunohistochemistry and Goldner's trichrome staining indicated that the number of osteoblasts in the infection group was significantly reduced ( P<0.05). TRAP staining indicated no significant difference in the number of osteoclasts between the infection and control groups ( P>0.05). Bioinformatics analysis found that staphylococcus aureus infection caused bone cell senescence and the JAK/STAT pathway was activated after the infection. Senescence β-Galactosidase staining suggested that senescent cells increased in the infection group compared with the control group. The number of Osterix and P16 positive senescent osteoprogenitor cells in the infection group was increased significantly compared with the control group. The number of senescent osteoprogenitor cells in the infection+JAKi group was significantly reduced and the bone loss was partially reversed after treatment of JAK inhibitor, compared with the infection group. Conclusion:Staphylococcus aureus may induce osteoprogenitor cell senescence through the JAK/STAT pathway and eventually lead to bone mass loss.

Objective: To investigate the value of platelet count in predicting the efficacy of rituximab treatment in chronic primary immune thrombocytopenia (ITP). Methods: A retrospective study was conducted in 103 chronic ITP patients hospitalized in our medical center between January 2011 and December 2014. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) of platelet count in different time points were analyzed for the predictor of treatment response. Optimal cutoff values were established using ROC analysis. Results: A total of 103 patients were included in the study. There were 46 males and 57 females, with a median age of 30 (18-67) years. At day 1, 3 and 7 after the first dose of rituximab, there was no significant difference in platelet counts between the success group (PLT≥50×10⁹/L after treatment) and the failure group (PLT≤50×10⁹/L after treatment) (P>0.05). At day 14 after rituximab treatment (PTD 14), platelet counts became significantly different in the success and failure groups[41(8-384)×10⁹/L vs 23(0-106)×10⁹/L, P=0.003], and remained different thereafter, with increasing significance in the subsequent follow-ups. Patients were divided further using an optimal cut-off platelet count of 50×10⁹/L on PTD 14, PTD 30, and PTD 60, and PPV and NPV values were calculated for predicting eventual success and failure. Conclusion Response can be predicted by obtaining platelet counts at 14, 30 and 60 days after rituximab treatment. The study proposed a protocol that guides patient monitoring and management planning.

Objective: To analyze the gene mutation spectrum, clinical features, and the factors of disease progression and prognosis in patients with essential thrombocytosis (ET) . Methods: A retrospective analysis was conducted on 178 newly diagnosed ET patients admitted from February 1st, 2009 to November 1st, 2018. Results: Of the 178 patients, 89 were male and 89 female, and the median diagnosis age was 49.5 (3-86) years old. JAK2V617F, CALR and MPL mutations frequencies were 16.45% (1.67%-43.90%) , 40.00% (10.00%-49.15%) and 25.10% (25.00%-40.00%) , respectively. Compared with patients with CALR mutations, patients with JAK2V617F mutation had higher diagnosis age (P=0.035) , higher white blood cell count (P=0.040) , higher hemoglobin concentration (P=0.001) , and lower platelet count (P=0.002) , respectively. Of them, 47 patients (27.01%) developed thrombotic events before diagnosis, and 3 ones (1.72%) experienced thrombotic events after diagnosis. Multivariate analysis revealed age >60 years (P=0.013, OR=4.595, 95%CI 1.382-15.282) and cardiovascular risk factors (CVF) (P<0.001, OR=8.873, 95%CI 2.921-26.955) as risk factors for thrombotic events, CALR mutation (P=0.032, OR=0.126, 95%CI 0.019-0.838) as a protective factor for thrombotic events. Age >60 years (P=0.042, OR=4.045, 95%CI 1.053-15.534) was found to be a risk factor for the overall survival (OS) of ET patients. OS of age ≤60 years and age>60 years were calculated by Kaplan-Meier analysis to be (115.231±1.899) months and (83.291±4.991) months (χ²=6.406, P=0.011) , respectively. Conclusion Age>60 years and CVF were risk factors for thrombotic event. CALR mutation was a protective factor for thrombotic event. Age >60 years was a risk factor for OS in ET patients.

Hemophilia B is a genetic disorder caused by coagulation factor Ⅸ(FⅨ) deficiency, mainly manifesting as joint, muscle and deep tissue bleeding. Hemophilia pseudotumor is a mass formed by soft tissue liquefaction and necrosis caused by repeated bleeding. Most pseudotumors occur in the bone and muscle. We report a case of hemophilia B with pseudotumor formation in the pelvis and abdomen, where lesion location is relatively rare. After active and effective hemostasis, the patient's hematuria symptom gradually improved. This case suggests that early and timely hemostatic treatment is crucial for patients with hemophilia.