Objective To explore the accuracy of high definition computed tomography angiography (HDCTA)in the evaluation of coronary in-stent restenosis.Methods 93 patients with 159 implanted coronary stents who underwent both HDCTA and CAG were included in the study.The sensitivity,specificity,positive predictive value (PPV),negative predictive value (NPV)and diag-nostic accordance rate of HDCTA were calculated.The imaging quality was analyzed by visual estimation.Possible factors that in-fluenced the diagnostic accuracy of HDCTA were evaluated,which included stent location,stent diameter and heart rate in the pa-tients with left anterior descending branch stents.Results Restenosis was found in 21 stents by CAG and 19 stents by HDCTA.The false positive and false negative were 5 and 3,respectively.Sensitivity,specificity,PPV,NPV and diagnostic accordance rate were 90.5%,96.4%,79.2%,98.5% and 95.6% respectively.The image quality was 4 score in 75 stents (47.1%),3 score in 33 (20.8%),2 score in 27 (17%),≤1 score in 24 (15.1%).The image quality of proximal segments,large stents (≥3.0 mm)and slow heart rate (<66 beast per minute)was significantly better than that of distal segments,small stents (<3.0 mm)and fast heart rate (≥6 6 beast per minute).Conclusion HDCTA is a convenient,efficient and non-invasive method for follow-up after im-plantation of the coronary artery stents.

In the United States of America, the physician group practice has become one of the most common practice models, and has a relatively perfect and clear system of laws and regulations in its monitoring.In view of the policy side, the federal government has published the Stark Law to regulate the registration, properties, operation, service contents in details for the physician group practice.Taking the market side, it is practiced to protect the physician groups and medical practice behaviors through medical insurance policies.In China, the emergence of physician group has received widespread attention and concern.But since the short development time and unclear development path, the relevant laws and regulations for physician groups are still are not perfect.This paper aims to summarize the development and status quo of the American physician group as well as the regulations related to the groups` operating system, which will provide a good reference to China.The purpose is to provide policy recommendations for the standardized development and perfect regulations of physician groups in China.The following recommendations were put forward: improve the relevant laws and regulations;promote the establishment of the corresponding security policies;speed up and enhance the research and development of medical liability insurance;do continuous tracking and timely summarize practices.

nclude positive vascular remodeling,low plaque density,spotty calcification,and eccentric stenosis.

In order to discover the steroid biotransformation ability of filamentous fungus Aspergillus niger TCCC41650, we studied the fermentation of 4-androstene-3,17-dione with A. niger TCCC41650. The transformation product was purified, crystallized and determined as 16β-hydroxy-androst-4-ene-3,17-dione by X-ray single crystal diffraction method. The best fermentation condition was found to be pH 6.0, ethanol amount 2% with a substrate concentration of 1 per thousand, the transformation rate is 85.81% after 72 h. Based on the best of our knowledge, 16β-hydroxylation rarely occurs in microbial transformations of steroid. This study laid the foundation for the research of 16β-hydroxylation steroids
Androstenedione ; metabolism ; Aspergillus niger ; metabolism ; Biotransformation ; Fermentation ; Hydroxylation ; Industrial Microbiology

Purpose To investigate the diagnostic value of the arrhythmogenic right ventricular dysplasia (ARVD) using multi-slice spiral CT (MSCT). Materials and Methods Thirty-four patients who were suspected as ARVD received right ventricular radiography, including 16 ARVD patients and 15 non-ARVD patients regarded as control group. The structural and shaped change of heart on reconstructed images of long axis, short axis and four cavity surface and analyze were observed, and MSCT features of right ventricular radiography characteristics were analyzed for ARVD patients. Results Sixteen cases of ARVD were correctly diagnosed by MSCT, and 14 cases had fatty infiltration including 11 cases of apex of heart, 8 cases of inferior wall, 5 cases of anterior wall, 5 cases of anterior wall of funnel area, 3 cases of diagram, 4 cases of papillary muscle, 6 cases of muscular trabecula and moderator band and 1 case of whole right ventricular free wall. Five cases showed scallop sign, 16 cases excessive trabecular change, 11 cases thinned changes, and 16 cases enlarged changes of right ventricular wall. Conclusion MSCT features of right ventricular for ARVD have relative diagnostic characteristics, and the scallop sign and excessive trabecular change of right ventricular wall are its specific imaging characteristics.

Objective To investigate the level of subpopulations of myeloid-derived suppressor cells (MDSCs) in elderly tumor-bearing mice versus elderly tumor-free mice,and to study the difference in immune suppressive functions between different subpopulations and their mechanisms.Methods A total of 20 healthy C57BL/6 elderly mice(aged 18-20 months) were randomly chosen to establish Lewis lung cancer models.The amount of monocytic-MDSCs (MO-MDSCs) and polymorphonuclear granulocytic-MDSCs(PMN-MDSCs) in tumor-free and tumor-bearing elderly mice was evaluated by using flow cytometry.MO-MDSCs and PMN-MDSCs were separated with Magnetic-Activated Cell Sorting (MACS) MicroBeads and their morphological characteristics were observed after May-Grunwald-Giemsa staining.The effects of MO-MDSCs and PMN-MDSCs on the proliferation of T cells were determined by Brdu-enzyme-linked immunosorbent assay(ELISA).And the immune suppressive mediators secreted by the subpopulations were detected by Real-time polymerase chain reaction(PCR).Results Compared to the tumor-free group,the proportion of MO-MDSCs in the spleen of tumorbearing group were increased [(12.44± 1.20) ％ vs.(38.42±3.66) ％,t=5.67,P＜0.001],while PMN-MDSCs were not [(10.34±0.68) ％ vs.(12.18±1.27) ％,t=2.21,P=0.09].The result of Brdu-ELISA showed that MO-MDSCs could suppress the proliferation of T cells [(0.30 ± 0.18) vs.(3.38±0.96),t=8.33,P＜0.001],while PMN MDSCs could not [(2.69±0.45)vs.(3.38±0.96),t =1.72,P=0.11].The result of PCR showed that as compared with PMN-MDSCs,Mo-MDSCs had the increased expression levels of arginase-1 (ARG-1),inducible nitric oxide synthase (iNOS),interleukin-10 (IL-10),interferon-γ(IFN-γ) (t =4.31,8.89,1.70,3.13,respectively,P ＜ 0.01 or 0.05),while the expression levels of interleukin-13 (IL-13),transforming growth factor-β(TGF-β) had no differences (t=4.94 and 2.75,P =0.39 and0.47).Conclusions MO-MDSCs are significantly increased in elderly Lewis lung cancer mice models.MO-MDSCs could mediate lung tumor evasion by suppressing the proliferation of T cells through highly expressing ARG-1,iNOS,IL-10 and IFN-γ.

Objective To explore the immune property and possible mechanism of the CD71+ CD235a+ nucleated erythroid cells from peripheral blood in elderly,as compared with those of healthy young.Methods Peripheral blood obtained by venipuncture from healthy young(n=59,mean age=28 years) and elderly(n=78,mean age=68 years)donors were measured by flow cytometry to evaluate the frequency of the CD71+ CD235a+ cells in peripheral blood mononuclear cells (PBMC).In vitro assays,CD71+ CD235a+ cells were sorted by flow cytometry and T cells were sorted using CD4+T cell isolation kit,then the T cell proliferation assays were conducted by following groups:T cell + CFSE group;T cell +CFSE co-cultured with CD71+ CD235a+ cells from the young donors;T cell + CFSE co-cultured with CD71+ CD235a+ cells from the older donors.Real-time PCR were used to identify the expression of the immune cytokine secreted by CD71+ CD235a+ cells.Results (1)the results showed a significant increase in the percentage of CD71+ CD235a+ cells in the elderly compared with the young [(9.93± 2.95)％ vs (1.96 ± 1.16)％,t =3.37,P ＜ 0.001];(2)the CD71+ CD235a+ cells from the older donors could suppress the proliferation of the T cells (t =2.91,P＜ 0.05)while from the young group we could not observe this phenomenon(t =0.387,P＞0.05).(3)The results of Real-time PCR revealed that,compared with CD71+ CD235a+ cells from the young,CD71+ CD235a+ cells from the elderly expressed higher levels of Arg-2 (t =9.04,P＜0.01),IL-1β,IL-6 and TGF-β(t =4.51,5.46,6.92,all P＜0.05).Conclusions There are higher frequencies of CD71+ CD235a+ cells in aged samples than the young.And the CD71+CD235a cells from the elderly could secrete more Arg-2,IL-1β,IL-6 and TGF-β to suppress the T cell proliferation.

Objective To explore the expression of negative costimulatory molecule B7-H1 of myeloid derived suppressor cells(MDSCs) and its roles in age-related immunosuppressive functions.Methods 36 C57BL/6 mice were divided into 2 groups:the elderly group(12-month-old,n=18) and the young group(4-8-week-old,n=18).The expressive level of negative costimulatory molecules of MDSCs in the two groups was measured by flow cytometry(FCM).Besides,MDSCs were sorted by using MDSC isolation kit and T cells were obtained by grinding lymph nodes.To explore the influence of B7-H1 on the MDSCs' immunosuppressive functions,T cell proliferation and intervention assay was conducted using the five following groups:T cells group,T cells + CFSE group [T cells with carboxyfluorescein diacetate succinimidyl ester(CFSE)],T cells +-CFSE cocultured with MDSCs from the young group,T cells + CFSE cocultured with MDSCs from the elderly group,and T cells + CFSE cocultured with MDSCs from elderly group and anti-B7-H1 blocking antibody.The effect of B7-H1 on T cell proliferation in MDSCs were observed.Results The expression level of B7-H1 of the MDSCs was significantly increased in the elderly group as compared with the young group(t=3.27,P＜0.05).T cell proliferation assay revealed that T cells were remarkably suppressed by MDSCs in elderly group as compared to the youth group(t=5.42,P＜0.05).The suppression of T cells by MDSCs was dramatically reversed by anti-B7-H1 blocking antibody in elderly group(t=8.28,P＜0.05).Conclusions B7-H1,a molecule expressed on the surface of MDSCs,plays a key role in the age-related immunosuppressive function of MDSCs.

Objective To evaluate images quality and diagnostic feasibility of low-dose CT in patients with traumatic rib fractures.Methods Twenty-five patients presented with thoracic iniury were underwent 64-slice spiral CT scanning in inspiration breath-hold technique.Two scan protocols were performed.In one scan protocol noise index(NI)is 11,and in another NI is 21,but the other scan parameters were no difference.The mean value of tube current,the volume CT dose index(CTDIvol),and effective dose(ED)were recorded.Image quality was scored by 2 experienced radiologists using the 5-points scale.The numbers and degrees of rib fractures were recorded.The data were tested by using the Wilcoxon signed rank sum test.The differences of the inter-observer were determined by Kappa statistics.Results The mean CTDIvol and ED in scan protocol with NI of 11 were(13.88±5.17)mGy and(8.14±3.21)mSv,and that with NI of 21 were(3.91±1.57)mGy and(2.31±0.97)mSv.Compared the scan with NI of 11.there was 72%intrinsie dose reduction in the scan with NI of 21.The mean value of tube current in scan with NI of 11 and 21 were(195.88±69.33)mAs and(54.56±21.54)mAs.AIl patients with 11 and Ⅲ degree and most patients with I degree rib fractures that identified by the scan with NT of 11 were detected by the scan with NI of 21.There were no statistical difference between two scaus with the Wilcoxon signed rank sum test.The diagnostic acceptability and image noise score in the scan with NI of 11 were 4.9±0.2 and 4.6±0.5.and that with NI=21 were 3.5±0.5 and 3.3±0.5.There was prefect concordante in the inter-observers in diagnostic acceptability on finding of rib fractures.diagnostic acceptability and image noise(Kappa=0.876,0.820,0.792,P<0.01)between two scan protocols.Conclusion Rib fractures can be diagnosed by the low-dose CT using the scan protocol with NI of 21.

Objective To investigate the association between serum homocysteine (Hcy) level and oxidative stress in elderly patients with obstructive sleep apnea/hypopnea syndrome (OSAHS). Methods The 123 patients from January 2007 to June 2010 were recruited and divided into the elderly OSAHS group (n=55) and the non-elderly OSAHS group (n=68). One hundred healthy subjects were selected and divided into the elderly control group (n=52) and the non-elderly control group (n=48). The PSG variables were recorded and the levels of Hcy, malondialdehyde (MDA) and glutathione (GSH) were detected after sleep in all subjects. Serum Hcy level was measured by cyclophorase, MDA and GSH levels were measured by spectrophotometer. Results There were statistical differences in Hcy concentration between four groups (F=28.26, P=0.000). The Hcy concentration was higher in elderly OSAHS group than in other groups, and was higher in elderly control group than in non-elderly control group, and was higher in non-elderly OSAHS group than in non-elderly control group. There were statistical differences in MDA and GSH concentrations between the four groups (F=5.56, P=0.002;F=4.79, P=0.004). The concentrations of MDA and GSH were higher in elderly OSAHS group than in other groups. Multiple regression analysis indicated a statistically significant relationship of Hcy concentration with age, MDA, GSH and AHI (β=0.07, 0.50, 0.23 and 2.00). Conclusions The concentration of Hcy increases and oxidative stress enhances with aging, especially in the elderly patients with OSAHS. The mechanism of high level of serum Hcy in elderly patients with OSAHS may be the high oxidative stress.