Cost-effective differentiation of hepatocyte-like cells from human pluripotent stem cells using small molecules

Significant efforts have been invested into the differentiation of stem cells into functional hepatocyte-like cells that can be used for cell therapy, disease modeling and drug screening. Most of these efforts have been concentrated on the use of growth factors to recapitulate developmental signals under in vitro conditions. Using small molecules instead of growth factors would provide an attractive alternative since small molecules are cell-permeable and cheaper than growth factors. We have developed a protocol for the differentiation of human embryonic stem cells into hepatocyte-like cells using a predominantly small molecule–based approach (SM-Hep). This 3 step differentiation strategy involves the use of optimized concentrations of LY294002 and bromo-indirubin-3’-oxime (BIO) for the generation of definitive endoderm; sodium butyrate and dimethyl sulfoxide (DMSO) for the generation of hepatoblasts and SB431542 for differentiation into hepatocyte-like cells. Activin A is the only growth factor required in this protocol. Our results showed that SM-Hep were morphologically and functionally similar or better compared to the hepatocytes derived from the growth-factor induced differentiation (GF-Hep) in terms of expression of hepatic markers, urea and albumin production and cytochrome P450 (CYP1A2 and CYP3A4) activities. Cell viability assays following treatment with paradigm hepatotoxicants Acetaminophen, Chlorpromazine, Diclofenac, Digoxin, Quinidine and Troglitazone showed that their sensitivity to these drugs was similar to human primary hepatocytes (PHHs). Using SM-Hep would result in 67% and 81% cost reduction compared to GF-Hep and PHHs respectively. Therefore, SM-Hep can serve as a robust and cost effective replacement for PHHs for drug screening and development.     

Evaluation of protection induced by a dengue virus serotype 2 envelope domain III protein scaffold/DNA vaccine in non-human primates

We describe the preclinical development of a dengue virus vaccine targeting the dengue virus serotype 2 (DENV2) envelope domain III (EDIII). This study provides proof-of-principle that a dengue EDIII protein scaffold/DNA vaccine can protect against dengue challenge. The dengue vaccine (EDIII-E2) is composed of both a protein particle and a DNA expression plasmid delivered simultaneously via intramuscular injection (protein) and gene gun (DNA) into rhesus macaques. The protein component can contain a maximum of 60 copies of EDIII presented on a multimeric scaffold of Geobacillus stearothermophilus E2 proteins. The DNA component is composed of the EDIII portion of the envelope gene cloned into an expression plasmid. The EDIII-E2 vaccine elicited robust antibody responses to DENV2, with neutralizing antibody responses detectable following the first boost and reaching titers of greater than 1:100,000 following the second and final boost. Vaccinated and naïve groups of macaques were challenged with DENV2. All vaccinated macaques were protected from detectable viremia by infectious assay, while naïve animals had detectable viremia for 2–7 days post-challenge. All naïve macaques had detectable viral RNA from day 2–10 post-challenge. In the EDIII-E2 group, three macaques were negative for viral RNA and three were found to have detectable viral RNA post challenge. Viremia onset was delayed and the duration was shortened relative to naïve controls. The presence of viral RNA post-challenge corresponded to a 10–30-fold boost in neutralization titers 28 days post challenge, whereas no boost was observed in the fully protected animals. Based on these results, we determine that pre-challenge 50% neutralization titers of >1:6000 correlated with sterilizing protection against DENV2 challenge in EDIII-E2 vaccinated macaques. Identification of the critical correlate of protection for the EDIII-E2 platform in the robust non-human primate model lays the groundwork for further development of a tetravalent EDIII-E2 dengue vaccine.     

黄芪丹参对多囊卵巢综合征大鼠雄激素/胰岛素受体表达影响的研究

目的：研究黄芪联合丹参对多囊卵巢综合征（PCOS）模型大鼠雄激素(AR)及胰岛素受体（INSR）表达的影响。方法：通过对大鼠注射外源性雄激素建立高雄激素无排卵模型，将建模成功的大鼠随机分为黄芪组、丹参组、黄芪＋丹参联合组以及模型组，每组10只，分别以黄芪、丹参、黄芪＋丹参联合用药行不同干预治疗，模型组用生理盐水灌胃。比较各组大鼠血清雄激素、胰岛素水平；卵巢AR、INSR mRNA及蛋白水平。结果：1）与模型组比较，黄芪组血清睾酮水平明显下降，丹参组血清胰岛素水平明显下降；联合组血清睾酮及胰岛素水平均明显下降。2）与模型组比较，黄芪组INSR蛋白水平明显下降，丹参组INSR蛋白水平明显上升；黄芪＋丹参联合组AR蛋白水平明显下降，同时INSR蛋白水平明显升高。3）与模型组比较，黄芪组AR mRNA水平明显下降，丹参组INSR mRNA水平明显上升；黄芪＋丹参联合组AR mRNA水平明显下降，同时卵巢INSR mRNA水平明显升高。结论：黄芪可改善PCOS的高雄激素状态，丹参可改善PCOS的高胰岛素状态，联合用药兼具抗雄激素及降低胰岛素的作用，AR、INSR表达的改变是其可能的作用机制之一。     

增强CT评价肝细胞癌凋亡相关蛋白表达的价值探讨

目的:探讨增强CT评价肝细胞癌(hepatocellular carcinoma,HCC)组织中凋亡相关蛋白fas,bax,bc1-2表达的价值。方法:对38例共40个经病理证实且行动、静脉双期CT增强扫描的HCC病灶进行分析,用免疫组化SP法检测癌组织中第Ⅷ因子相关抗原(FactorⅧrelated antigen,FⅧRA),fas,bax,bc1-2和bc1-x1的表达情况,并结合其病理分级将CT增强表现特征与免疫组化的结果进行对照分析。结果:fas,bax,bc1-2和bc1-x1的阳性表达率分别为20%(8/40)、25%(10/40)、27.5%(11/40)和50%(20/40),bax和bc1-2,以及bc1-2和bc1-x1之间分别具有一定的相关性(P<0.05)。bc1-x1的表达与CT显示的病灶大小、以及病理分级具有一定的关系(P<0.05),病理分级与CT显示的边界类型以及瘤内的液化坏死有关(P<0.05)。结论:fas,bax,bc1-2和bc1-x1等蛋白在HCC组织中呈现不同程度的表达,通过CT反映调亡相关蛋白表达的价值有限。     

急性脑梗死血清C-反应蛋白的临床分析

目的观察急性脑梗死患者血清CRP在发病中的作用及临床意义。方法采用免疫比浊法对60例急性脑梗死患者的血清CRP水平进行动态观察（病程第1．7及14天），并与45例健康人进行比较。结果急性脑梗死患者血清CRP从病程第1天即升高（P〈0．01），至第7天达高峰，以后降低；重型患者明显高于轻、中型患者。结论血清CRP可能在急性脑梗死的发生、发展中起一定作用，并与病情严重程度呈正相关。     

检测子宫内膜异位症患者血清中差异表达蛋白的研究

目的：检测子宫内膜异位症（内异症）患者血清中差异表达的蛋白。方法：采用表面增强激光解吸／离子化飞行时间质谱（SELDI—TOF—MS）技术，选用WCX2蛋白质芯片对50例内异症及48例对照组血清标本进行检测以筛选内异症血清中差异表达的蛋白。结果：在Mr 0～50000范围内，检测出106个蛋白峰。内异症患者血清中差异表达的蛋白峰有4个。将发现的差异蛋白峰在Swiss蛋白数据库中搜索，发现Mr 9280蛋白峰与玻璃粘连蛋白Vitronectin相符。Vitronectin属于整合素家族，在内异症的粘附、侵袭、血管形成过程中起重要作用。其他的蛋白峰没有发现与之相匹配的蛋白，提示可能为新的蛋白质。结论：内异症患者血清中存在差异表达的蛋白，其对内异症的早期诊断具有一定的临床意义。SELDI蛋白芯片技术是一种快速、简单易行、样本用量少、高通量、重复性好的分析方法，具有广阔的临床应用前景。     

溃疡性结肠炎患者外周血中性粒细胞凋亡与粘附分子水平的关系及意义

目的　探讨溃疡性结肠炎 (U C)患者外周血中性粒细胞 (PMN)凋亡机制。方法　采用流式细胞术检测 32例 UC患者外周血 PMN凋亡 ,EL ISA法检测 P-选择素 (P- sel)和细胞间粘附分子 - 1(ICAM- 1)的水平。结果　活动期 UC患者 PMN凋亡率明显低于对照组和缓解期 UC患者 (P<0 .0 1)。不同病情活动期 U C患者 PMN凋亡有显著性差异 (P<0 .0 1)。活动期 UC患者外周血中 P- sel和 ICAM- 1水平均高于对照组和缓解期 U C患者(P<0 .0 1或 (P<0 .0 5 ) ,且与 PMN凋亡呈负相关 (r值分别为 - 0 .72 38和 - 0 .5 2 13,P均 <0 .0 1) ,与病情呈正相关。结论　各种免疫细胞粘附分子表达上调可能是导致 UC患者 PMN凋亡延迟的重要机制     

C反应蛋白测定在小儿败血症中的应用

目的　本研究的目的在了解C反应蛋白的 (CRP)测定对于小儿败血症的诊断价值。方法　连续选取2 0例白细胞总数不高的小儿败血症患者 ,作回顾性研究对象。比较其治疗前和治疗后 7～ 1 0d后疾病的痊愈或明显好转时CRP水平 ,并与体温、白细胞分类结果进行比较。结果　治疗后CRP水平 (0 57± 0 68μg/ml)显著低于治疗前水平 (5 90± 3 57μg/ml) ,P <0 0 0 1 ;治疗前CRP的阳性率为 1 0 0 % ,显著高于嗜中性粒细胞比率 >75 %的阳性率 (30 % )和体温高于 37 5℃的阳性率 (30 % ) ,P <0 0 0 5。结论　CRP可以作为一种反映细菌感染的敏感指标 ,有助于不典型小儿败血症的诊断和疗效观察。     

Effect of UVB 311 nm irradiation on normal human skin

Ultraviolet radiation B (UVB) on the skin induces erythema, inflammation and modifications of the immune system. These changes have been reported after excessive short-term or long-term exposure to broad spectrum UVB. In this study, we examined the effects of local repetitive UVB irradiation of 311 nm wavelength on the skin of seven young volunteers. Skin biopsies were taken before and after UVB irradiation, and we immunohistochemically analyzed the expression of CD1a and HLA-DR antigens of Langerhans cells (LC), the possible infiltration of dermis/epidermis by CD11b macrophages, the modifications or the induction of intercellular adhesion molecule-1 (ICAM-1), E-selectin and vascular cell adhesion molecule-1 (VCAM-1) involved in the binding of leukocytes to the endothelial surface and the development of perivascular infiltrates of LFA-1⁺ mononuclear cells. We also determined the expression of substance P receptors (SPR) using biotinylated substance P (SPB). Exposure of UVB 311 nm induced a drastic reduction of CD1a⁺ cells and a moderate increase of HLA-DR⁺ dendritic cells in the epidermis without infiltration by CD11b macrophages. An increase of the binding of SPB to upper layer epidermal cells was noted in five of seven biopsies. In the dermis, vessel-associated ICAM-1 expression increased and an induction of E-selectin occurred on nearly 20 to 40% of endothelial cells, but VCAM-1 expression remained undetectable. The percentage of LFA-1⁺ cells did not change significantly after irradiation. These observations may be compatible with a selective role of UVB 311 nm on the skin immune response.     

重组结核分支杆菌16000蛋白抗原(rPA16)的免疫原性研究

目的：研究结核分枝杆菌重组16000蛋白（rPA16)诱发家兔产生抗体的能力并评价其血清学诊断的价值。方法：家兔按注射的抗原及佐剂的不同分组，皮下多点注射分别进行免疫，6次免疫后采血，双向琼脂扩散试验和酶联免疫吸附试验（ELISA）跟踪兔血清抗体效价的时间效应并检测兔血清与所试各类分支杆菌PPD有无交叉反应；同时检测rPA16与各分支杆菌PPD的免疫羊血清的反应，并用rPA16抗原检测人血标本，分析该抗原的临床检测的敏感性和特异性。结果：兔血清抗体效价结果显示：5个月后，加佐剂的抗原组的兔免疫血清仍能检测到抗体，不加佐剂组2个月后血清抗体检测即为阴性，ELISA检测兔免疫血清比双向琼脂扩散方法要更敏感，rPA16抗原加佐剂引起的兔血清抗体滴度最高可达1：6400，不加佐剂组的血清抗体滴度仅为1：400，ELISA法分析抗rPA16的兔血清的特异性表明其特异笥较好，仅与牛、人型结核分支杆菌的PPD呈阳性反应，与其他所试分支杆菌PPD反应均为阴性，同时又分析了rPA16抗原的特异性，与人型PPD相比，该抗原只与所试各类分支杆菌，BCG、牛分支杆菌免疫的血清呈阳性反应，而人型PPD则基本上与结核分支杆菌免疫的血清均呈阳性反应，ELISA检测血清标本结果：肺结核病组中rPA16和PPD检测敏感性分别为64.8%和75.2%；健康组，卡介苗接种阳转健康组，rPA16和PPD检测特异性分别为96.2%,88.5%和94.3%,66.7%。结论：rPA16具有较强的免疫原性和一定的特异性，可能成为结核病血清学诊断试剂之一。