Antimicrobial Resistance of Staphylococcus aureus in Our Hospital over the Last 10 Years / 中国医科大学学报

Objective To retrospectively analyze the clinical distribution and changes in antimicrobial resistance profiles of Staphylococcus aureus (S. aureus). Methods We collected clinical specimens of S. aureus from The First Hospital of China Medical University. The Vitek-2 and BD Phoenix 100 were performed for bacterial identification and drug sensitivity tests,and WHONET 5.6 was used to analyze the data. Results From 2007 to 2016,there were 3 377 unrepeatable strains of S. aureus,including 1 705 that were methicillin resistant S. aureus (MRSA). The isolation rate of S. aureus was 9.4 ％ and of these,50.5 ％ were MRSA. There were 776 S. aureus specimens from outpatients or the emergency department,including 16.8 ％ MRSA,and 2 011 S. aureus from inpatient departments,including 60.2 ％ MRSA. The main sources of specimens were sputum (41.8 ％),pus (17.9 ％),and body secretions (17.5 ％). The average resistance rates of MRSA for erythromycin,ofloxacin,ciprofloxacin,gentamycin,and tetracycline were higher than 75.0 ％. The average resistance rate of methicillin sensitive S. aureus (MSSA) for erythromycin was up to 76.8 ％,and for tetracycline,gentamycin,ciprofloxacin,and ofloxacin,were less than 25.0 ％. In 10 years,the average resistance rates of MRSA and MSSA for 11 kinds of common antibiotics had no obvious change. Conclusion The constituent rate of MRSA was high in The First Hospital of China Medical University,especially from the areas that were not sterile,suggesting that clinicians should pay attention to the identification of infection and sources for MRSA,which were from such areas. Hospital infection control should be focused on at the same time,in order to reduce the incidence of MRSA.

Influence of Progesterone and Vitamin D on the Cell Proliferation of Hormone-dependent Breast Cancer and the Interaction / 中国医科大学学报

Objective To study the influence of progesterone on the cell proliferation of hormone?dependent breast cancer and observe the co?effect of vitamin D and progesterone of different levels on the proliferation of the cell line T?47D in hormone?dependent breast cancer and the interaction be?tween vitamin D and progesterone. Methods The cultured T?47D cells were divided into the high and the low progesterone mono?treated groups to observe the effects of different levels of progesterone on the cell proliferation of hormone?dependent breast cancer cell line(T?47D). The high and the low vitamin D mono?treated groups were set to observe the effects of different levels of vitamin D on the cell proliferation. Groups treated by differ?ent levels of progesterone combined with vitamin D were set to observe the interaction between them. Normal breast cancer cells were set as the con?trol group. The two?factor two?level parallel factorial experiment was conducted to observe the co?effect of different levels of progesterone and vitamin D on the proliferation of T?47D. The growth and apoptosis of cells was observed through detection of absorbance in each group by MTT. Results The cell concentration in high and low progesterone treated groups was increased than that in the control group,and was increased in the low proges?terone treated group compared with the high progesterone treated group(P<0.05). The cell concentration in dual?low level treated group was de?creased than that in the other three groups which were two?factor treated and the control group(P<0.05). Conclusion Progesterone stimulates the cell proliferation of hormone?dependent breast cancer. The concentration?based interaction between vitamin D and progesterone indicates that the bi?directional effect of progesterone on breast cancer cells may be related to the concentration of progesterone and other factors,but the specific interac?tion and the mechanism is unclear.

Crystal structures of the two membrane-proximal Ig-like domains (D3D4) of LILRB1/B2: alternative models for their involvement in peptide-HLA binding

Leukocyte immunoglobulin-like receptors (LILRs), also called CD85s, ILTs, or LIRs, are important mediators of immune activation and tolerance that contain tandem immunoglobulin (Ig)-like folds. There are 11 (in addition to two pseudogenes) LILRs in total, two with two Ig-like domains (D1D2) and the remaining nine with four Ig-like domains (D1D2D3D4). Thus far, the structural features of the D1D2 domains of LILR proteins are well defined, but no structures for the D3D4 domains have been reported. This is a very important field to be studied as it relates to the unknown functions of the D3D4 domains, as well as their relative orientation to the D1D2 domains on the cell surface. Here, we report the crystal structures of the D3D4 domains of both LILRB1 and LILRB2. The two Ig-like domains of both LILRB1-D3D4 and LILRB2-D3D4 are arranged at an acute angle (∼60°) to form a bent structure, resembling the structures of natural killer inhibitory receptors. Based on these two D3D4 domain structures and previously reported D1D2/HLA I complex structures, two alternative models of full-length (four Ig-like domains) LILR molecules bound to HLA I are proposed.

A novel xeno-free and feeder-cell-free system for human pluripotent stem cell culture

While human induced pluripotent stem cells (hiPSCs) have promising applications in regenerative medicine, most of the hiPSC lines available today are not suitable for clinical applications due to contamination with nonhuman materials, such as sialic acid, and potential pathogens from animal-product-containing cell culture systems. Although several xeno-free cell culture systems have been established recently, their use of human fibroblasts as feeders reduces the clinical potential of hiPSCs due to batch-to-batch variation in the feeders and time-consuming preparation processes. In this study, we have developed a xeno-free and feeder-cell-free human embryonic stem cell (hESC)/hiPSC culture system using human plasma and human placenta extracts. The system maintains the self-renewing capacity and pluripotency of hESCs for more than 40 passages. Human iPSCs were also derived from human dermal fibroblasts using this culture system by overexpressing three transcription factors-Oct4, Sox2 and Nanog. The culture system developed here is inexpensive and suitable for large scale production.

The clinical significance of urinary B-type natriuretic peptide assay for the diagnosis of chronic heart failure / 中华检验医学杂志

ObjectiveTo investigate the value of urinary BNP for diagnosis of chronic heart failure (CHF). MethodsThe levels of Urinary BNP and plasma BNP were measured by microparticle enzyme immunoassay (MEIA) in 83 patients with CHF and 30 control subjects. The heart function was classified according totheNYHAcriteria. Leftventricularejectionfractions(LVEF)weremeasuredby echocardiology. ResultsThe level of urinary BNP in patients with CHF was[90. 0(38. 3 -209. 5 )]ng/L and the level of plasma BNP was[680. 0 ( 289. 7 - 1543.5)]ng/L, both of them were much higher than those in healthy subjects,[17. 0 ( 13.0 - 33. 0)]ng/L and[84. 5 ( 56. 0 - 158.0 )]ng/L, respectively (P＜0. 01 ). The concentrations of urinary BNP increased gradually with more severe symptoms ( NYHA cl ass Ⅰ -ⅣV ). The level of urinary BNP was positively correlated with NYHA class ( r = 0. 742, P ＜ 0. 01 )and the level of plasma BNP (r =0. 842,P ＜0. 01 ) while negatively related with LVEF (r = -0. 801 ,P ＜0. 01 ). The level of urinary BNP in patients with LVEF ＜ 40％ was[143.0 ( 85. 0 - 258.0)]ng/L , which was much higher than that in patients with LVEF≥40％ ,[31.5( 17.3 -38. 8)]ng/L, (P ＜0. 01 ). At a decision threshold of 36. 5 ng/L, the urine BNP assay demonstrated a clinical sensitivity and specificity of 84％ and 80％ ,respectively. In this study,the area under the curve(AUC) was 0. 905. ConclusionUrinary BNP is a new candidate marker for the diagnosis of CHF,it provides a similar accuracy with plasma BNP.