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Background The chronic injury of the hematopoietic system caused by ionizing radiation (IR) is often ignored. The essential cause of this injury is the damage of hematopoietic stem and progenitor cells (HSPCs). Objective To explore the long-term effects of IR at different radiation doses and at different radiation fractions of the same radiation dose on HSPCs in the bone marrow of mice, and to provide a scientific basis for reducing the chronic damage to the hematopoietic system caused by IR. Methods A total of 16 male C57BL/6 mice aged 8-10 weeks were randomly divided into four groups that received different doses or fractions of total body X-ray irradiation, including 1.5 Gy×4 irradiation group (n=5), 3 Gy irradiation group (n=4), 6 Gy irradiation group (n=4), and non-irradiation group (n=3). Two months after irradiation, bone marrow cells from each mouse were collected and counted. The clone forming ability of bone marrow cells was analyzed by cobblestone area-forming cell (CAFC) assay. The proportion of HSPCs was measured by flow cytometry. The cell cycle of HSPCs was assessed by antigen identified by monoclonal antibody Ki 67 (Ki-67) and 7-amino-actinomycin D (7-AAD) double staining. The reactive oxygen species (ROS) levels of HSPCs were estimated with a 2,7-dichlorodihydrofluorescein diacetate (DCFDA) probe. The cellular senescence of HSPCs was evaluated with a 5-dodecanoylaminofluorescein di-β-D-galactopyranoside (C12FDG) probe. The expression of senescence related genes such as P16, P19, P21, and P27 was measured by real-time fluorescence quantitative PCR. Results There was no significant change in the numbers of bone marrow cells 2 months after different doses and fractions of radiation (P>0.05). The clone forming ability of bone marrow cells was significantly decreased after 3 Gy and 6 Gy irradiation when compared to non-irradiated mice (P<0.01). HSPCs responded inconsistently to different doses and fractions of irradiation. Overall, there was no significant change in long-term hematopoietic stem cells (LT-HSCs) proportion after irradiation (P>0.05), the proportions of hematopoietic progenitor cells (HPCs), hematopoietic stem cells (HSCs), short-term hematopoietic stem cells (ST-HSCs), and multipotent progenitors 2 (MPP2) increased after irradiation (P<0.05), and the proportions of LSK, MPP1, MPP3, and MPP4 cells decreased after irradiation (P<0.05); except for HPCs and MPP2, the proportion of HSPCs in G0 phase was decreased (P<0.05). The ROS production in HSPCs was increased significantly after 6 Gy irradiation (P<0.05), while the ROS levels after 3 Gy and 1.5 Gy×4 irradiation were similar to that of the non-radiation group (P>0.05). The cellular senescent proportion of HPCs, LSK, and HSCs increased after irradiation (P<0.05). The expression levels of senescence related genes P16, P19, and P21 in HSCs were significantly increased (P<0.05). Conclusion The responses of HSPCs in bone marrow to IR vary depending on doses and fractions of irradiation. Increased ROS production and cellular senescence may be involved in the damage process of HSPCs under radiation settings.
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Objective:To test the validity and reliability of the General Alienation Scale (GAS)in college students sample.Methods:Totally 1200 college students were surveyed,using classical test theory (CTT)and i-tem response theory (IRT)to test the psychometric properties of GAS.Under the framework of CTT,item selec-tion was performed with all data.Then,the sample was divided into two groups based on the input order to exam-ine the construct validity.Exploratory factor analysis (EFA)and parallel analysis (PA)were performed with odd group,while confirmatory factor analysis (CFA)was performed with even group.Criterion validity was examined with the short-form of the University of California Los Angeles Loneliness Scale (ULS-8),General Self-Efficacy Scale (GSES),Rosenberg Self-Esteem Scale (RSES).Under the framework of IRT,all data was fitted the rat-ing scale model (RSM),including the principal component analysis of residuals (PCAR),the item fit indexes (Infit and Outfit),measurement reliability (item separation index,item reliability,person separation index and person reliability)and the Wright map.Results:Under the framework of CTT,the GAS was retained 13 items except item 2 and 5.The results of both EFA and PA showed that 13 items of GAS was one-dimensional,and there was a good fit of CFA (χ2 /df=2.689,P scores respectively (Ps <0.001 ).The Cronbach 's αcoefficient and confidence interval were 0.81 (0.80, 0.83).Under the framework of IRT,the ratio of first-paired eigenvalue was 1.6 in PCAR.The infit and outfit of retaining 13 items in CTT were from 0.6 to 1.4 excluding item 4.The item separation index,item reliability,per-son separation index and person reliability of the 12-item GAS were10.91,0.99,2.14 and 0.82 respectively.The item difficulty can matched with person ability,and they were closed to the normal distribution.Conclusion:It suggests that the General Alienation Scale (GAS)is of good validity and reliability,and it could be used as an ef-fective tool for measuring the alienation of college students.
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This article was to discuss the effectiveness of medial sural artery perforator pedicled flap or muscle flap in the treatment of soft tissue defect. Since 2002, 21 patients(14 males and 7 females)with prepatellar(n=7)or pretibial(n=14)defect had underwent soft tissue reconstruction. Ten of them obtained medial sural artery perforator pedicled flap and the rest received muscle flap. All the medial sural artery perforator pedicled flaps and muscle flaps survived well and the clinical outcomes were satisfactory. No remarkable donor site morbidity was found. According to our data. medial sural artery perforator pedicled flap or muscle flap may seem to be highly vascularized and have constant vascular anatomy and long vascular pedicle. They could be useful in the treatment of prepatellar or pretibial soft tissue defect.
ABSTRACT
Objective To summarize clinical application of the medial sural artery perforator pedicled flap for the coverage of soft tissue defects around the knee and upper one third of lower leg.Methods From May 2003 tO January 2007,16 patients(11 men,5 women)with soft tissue defects around the knee and upper one third of lower leg underwent reconstruction with the medial sural artery perforator pedicled flap.Of them,4 eases recipient site were located on the prepatellar region,2 cases were located on the anterolateral pateflar,1 case was located on the anteromedial patellar,and 9 cases upper one third oflowerleg.They ranged in age from 23 to 52 years(mean,36 years).The donor leg was ipsilateral in all cages. Results One ca8e sustained superficial infection postoperative and the gradual wound healed by daily wound dressings.All the flaps had survived completely without major complication with satisfactory clinical results. Follow-up period ranged from 3.0 months to 3.5 years(mean, 1.7 years)postoperatively.There was no remarkable donor site morbidity.All cases had good appearance and function in recipient site.There was no remarkable donor site morbidity. Conclusion The medial sural artery perforator flap is nourished by the musculocutaneous perforater of the medial sural artery.The flaps seem to has highly vascularize,a constant vascular anatomy and a long vascular pedicle.The flap is thin and suitable for the coverage of soft tissue defects around the knee and upper one third of lower leg.