亮度知觉效应与视觉加工方式研究

目的:利用微持续与微间隔时间技术,设计了两组相关的实验,对亮度知觉效应和视觉加工方式进行探讨。方法:实验于2006-06在中南民族大学物理楼脑认知实验室进行,所有受试者为年龄20～25岁的大学本科生,视力(含矫正视力)正常,均为右利手。①实验1:被试为10名(男5名,女5名),要求被试分别对n屏依次呈现的亮块的明度和n 1屏依次呈现的亮块的明度进行比较(n≤17)。②实验2:被试为28名(男13名,女15名),实验涉及两个刺激物,先呈现的刺激物由左右两个大小相同、亮度不同的亮块a和b组成,后呈现的刺激物把a和b的位置进行对调,当这两个刺激物依次显示时,要求被试报告左右两边的明度是否存在差异,存在何种差异。结果:①实验1∶1≤n≤3时,100%的被试报告,n 1屏的明度大于n屏的亮度,即n 1>n;4≤n≤10时,70%～90%的被试报告n 1>n;n>10时,50%～70%的被试报告n 1>n;随着n值的增加明度差异也在减小,大约在n=17时达到稳定,n屏和n 1屏的明度区别将很难被看出。②实验2:在L(a)b a,随着a和b的亮度差异减小,左右两边呈现的明度越相似;同样当L(a)相似文献   

体外受精超促排卵治疗中单用促性腺激素和拮抗剂方案临床结局的比较

目的探讨体外受精(IVF)治疗中单用促性腺激素(Gn)对妊娠结局的影响。方法月经第3日开始给予重组卵泡刺激素(rFSH)促排卵,促排卵第6日开始监测血激素水平和阴道超声监测卵泡大小。将达到思则凯添加标准者[黄体生成素(LH)5 IU/L,或LH/基础LH≥3]设为对照组,每日给予思则凯0.125 mg直至人绒毛膜促性腺激素(hCG)注射日;以未达到标准不使用思则凯者设为研究组。结果研究组(n=31)和对照组(n=49)患者在Gn剂量、促排卵天数、hCG注射日血清内分泌水平、获卵数、受精率、着床率、临床妊娠率和活产率方面均无统计学差异(P0.05)。结论在IVF促排卵治疗中,通过对血清LH的监测,如果LH维持在低水平可以不给予拮抗剂治疗,单纯使用Gn是一种经济有效的促排卵方案。     

巨细胞病毒感染致儿童肾损伤的探讨

在我国巨细胞病毒(CMV)感染率较高,其中儿童CMV感染率高达83％,为探讨CMV感染对儿童肾脏的影响,2003年3～7月分别对63例住院患儿尿中CMV、血清胱氨酸蛋白酶抑制剂C(cystatinC)、尿转铁蛋白(TRF)和α1-微球蛋白(α1-MG)进行了检测,并作一分析。     

B7.2-Ig fusion proteins enhance IL-4-dependent differentiation of tumor-sensitized CD8+ cytotoxic T lymphocyte precursors

The B7/CD28 co-stimulatory pathway plays a critical role in T cell activation and differentiation. Our previous study demonstrated that administration of B7.2-Ig fusion proteins to tumor-bearing mice elicits IL-4-dependent, CD8+ T cell-mediated tumor regression. Here, we investigated whether B7.2-Ig stimulation of tumor-sensitized CD8+ CTL precursors during in vitro antigen re-sensitization actually results in their differentiation into mature CTLs and if so, whether such a process depends on IL-4 signals. Splenocytes from tumor-sensitized (tumor-bearing or tumor-immunized) mice exhibited low levels of anti-tumor CTL responses upon culturing alone, but induced strikingly enhanced CTL responses when stimulated in vitro with B7.2-Ig fusion proteins. Because CTLs were not generated from normal splenocytes even by B7.2-Ig stimulation, the expression of the B7.2-Ig effect required the in vivo tumor sensitization of CD8+ CTL precursors. Administration of anti-CD4 or anti-CD40 ligand (CD40L) to mice before tumor sensitization resulted in almost complete inhibition of CTL responses generated in the subsequent culture containing B7.2-Ig. In contrast, anti-IL-4 did not influence in vivo tumor sensitization required for CTL induction. However, B7.2-Ig stimulation of tumor-sensitized splenocytes enhanced IL-4 production and neutralization of this IL-4 with anti-IL-4 potently down-regulated CTL responses. These results indicate that B7.2-Ig enhances IL-4-dependent differentiation of anti-tumor CD8+ CTL precursors that can be sensitized in vivo depending on collaboration with CD4+ T cells involving CD40L function.     

家兔阑尾淋巴管铸型的扫描电镜研究

用淋巴管铸型、冰冻断裂样品及半薄切片样品观察了家兔阑尾巴管及泡周围淋巴窦的立体构筑，可见在阑尾粘膜浅层存在一层毛细淋巴管网，粘膜深层有致密的毛细淋巴管丛，从毛细淋巴管丛发出许多短树枝样毛细淋巴管伸向胸腺依赖区。从粘膜浅层毛细淋忱网及粘膜深层毛细淋巴管丛都发出与腔面垂直的毛细淋巴管，与滤泡周围淋巴窦相连，滤泡周围淋巴窦位于淋巴滤泡的外面和底面从腔面观察，滤泡财要巴窦与粘膜深层的毛细淋巴管丛共同形成茶     

不同造模方法所致“热毒血瘀证”模型家兔血液流变学改变的比较研究

本文通过金葡菌、大肠杆菌内毒素、地塞米松加内毒素等三种不同的攻毒方法复制了“热毒血瘀证”的动物模型。结果提示三种模型在血凝学指标上均表现为KPTT、PT明显缩短,而在血液流变学指标上则有不同。金葡菌所造模型表现为明显的高粘状态,内毒素模型则表现为明显的低粘状态,地塞米松加内毒素模型则改变不明显。     

星形细胞肿瘤p53蛋白和PCNA免疫组化及其临床病理意义

应用免疫组化和图象分析技术对人脑星形细胞肿瘤中抑癌基因ｐ５３蛋白（４７例）和增殖细胞核抗原（ＰＣＮＡ）（９７例）的定位、分布及反应强度与分级和预后的关系进行了研究。结果显示；３种ｐ５３蛋白抗体的阳性率为２３．４％～６６．７％，其中ＣＭ－１抗体阳性率高于ｐＡｂ１８０１和ｐＡｂ２４０；ｐ５３表达水平在Ⅱ～Ⅳ级高于１级，并与ＰＣＮＡ标记指数之间相关。ＰＣＮＡ反应强度既与分级相关，又与预后相关，对于分析星形细胞瘤增殖活性和恶性程度有重要意义。     

MicroRNA 21 Inhibits Left Ventricular Remodeling in the Early Phase of Rat Model with Ischemia-reperfusion Injury by Suppressing Cell Apoptosis

Objective: To determine the role of microRNA 21(miR-21) on left ventricular remodeling of rat heart with ischemia-reperfusion (I/R) injury and to investigate the underlying mechanism of miR-21 mediated myocardium protection.Methods: Rats were randomly divided into three groups: an I/R model group with Ad-GFP (Ad-GFP group), an I/R model group with Ad-miR-21 (Ad-miR-21 group) and a sham-surgery group. Changes in hemodynamic parameters were recorded at 1 week after I/R. Histological diagnosis was achieved by hematoxylin and eosin (H&E). Left ventricular (LV) dimensions, myocardial infarct size, LV/BW, collagen type Ⅰ, type Ⅲ and PCNA positive cells were measured. Primary cultures of neonatal rat cardiac ventricular myocytes were performed and cell ischemic injury was induced by hypoxia in a serum- and glucose-free medium, and reoxygenation (H/R).MiR-21 inhibitor and pre-miR-21 were respectively added to the culture medium for the miR-21 knockdown and for the miR-21 up-regulation. qRT-PCR was used to determine the miR-21 levels in cultured cells. Flow cytometry was performed to examine the cell apoptosis.Results: In the Ad-miR-21 group, LV dimensions, myocardial infarct size, LV/BW, collagen type Ⅰ, type Ⅲ and PCNA positive cells all significantly decreased compared with the Ad-GFP group. At 1 week after I/R, the Ad-miR-21 significantly improved LVSP, LV +dp/dt(max), LV - dp/dt(min), and decreased heart rate (HR) and LVEDP compared with the Ad-GFP group. Compared with the Ad-GFP, the cell apoptotic rate significantly decreased in the Ad-miR-21 group. The miR-21 inhibitor exacerbated cardiac myocyte apoptosis and the pre-miR-21 decreased hypoxia/reoxygenation- induced cardiac myocyte apoptosis.Conclusions: Ad-miR-21 improves LV remodeling and decreases the apoptosis of myocardial cells, suggesting the possible mechanism by which Ad-miR-21 functions in protecting against I/R injury.     

Visceral hyperalgesia induced by neonatal maternal separation is associated with nerve growth factor-mediated central neuronal plasticity in rat spinal cord

Neonatal maternal separation (NMS) has been shown to trigger alterations in neuroendocrine, neurochemical and sensory response to nociceptive stimuli along the brain-gut axis. These alterations may be the result of a cascade of events that are regulated by neurotrophic factors. Nerve growth factor (NGF), a member of the neurotrophin family, is essential for the development and maintenance of sensory neurons and for the formation of central pain circuitry. The present study aimed to investigate whether NMS causes changes in neuronal plasticity and the relationship of these changes in plasticity with the expression of NGF and its high affinity tyrosine kinase receptor A (TrkA) in the lumbosacral spinal cord in adult rats. Male Wistar rat pups were either subjected to 180 min daily of NMS or not handled (NH) for 13 consecutive days. The expression of NGF and TrkA was examined in NH and NMS rats with or without colorectal distention (CRD) as determined by Western blot analysis and immunohistochemistry. The present results of Western blot analysis indicated NMS and CRD have a significant effect on NGF protein level in the lumbosacral spinal cord of rats. Assessments of optical densities revealed that NMS enhanced TrkA-ir fiber densities in laminae I-III and laminae V-VI of rats in both conditions with or without CRD. Double immunofluorescence revealed that TrkA co-expressed with calcitonin gene-related peptide (CGRP) in afferent fibers, while no significant difference in terms of the intensity of TrkA-ir in these fibers was found among groups. Quantitative analysis of TrkA-ir neurons indicated a significant interactive effect of NMS and CRD on the mean number of TrkA-ir neurons in laminae V-VI of rats, in which significant difference was found between NMS+CRD and NH+CRD. Double immunofluorescence of TrkA and Fos showed that CRD has a significant effect on TrkA expression in Fos-positive neurons in laminae V-VI and lamina X of rats, while no significant difference was found between NMS+CRD and NH+CRD. These results demonstrate that NMS induced alterations in NGF protein level and TrkA expression in adult rat spinal cord and indicate that NGF is a crucial mediator for the changes in neuronal plasticity that occur in NMS-induced visceral hyperalgesia.     

Region-of-interest image reconstruction in circular cone-beam microCT

Cone-beam microcomputed tomography (microCT) is one of the most popular choices for small animal imaging which is becoming an important tool for studying animal models with transplanted diseases. Region-of-interest (ROI) imaging techniques in CT, which can reconstruct an ROI image from the projection data set of the ROI, can be used not only for reducing imaging-radiation exposure to the subject and scatters to the detector but also for potentially increasing spatial resolution of the reconstructed images. Increasing spatial resolution in microCT images can facilitate improved accuracy in many assessment tasks. A method proposed previously for increasing CT image spatial resolution entails the exploitation of the geometric magnification in cone-beam CT. Due to finite detector size, however, this method can lead to data truncation for a large geometric magnification. The Feldkamp-Davis-Kress (FDK) algorithm yields images with artifacts when truncated data are used, whereas the recently developed backprojection filtration (BPF) algorithm is capable of reconstructing ROI images without truncation artifacts from truncated cone-beam data. We apply the BPF algorithm to reconstructing ROI images from truncated data of three different objects acquired by our circular cone-beam microCT system. Reconstructed images by use of the FDK and BPF algorithms from both truncated and nontruncated cone-beam data are compared. The results of the experimental studies demonstrate that, from certain truncated data, the BPF algorithm can reconstruct ROI images with quality comparable to that reconstructed from nontruncated data. In contrast, the FDK algorithm yields ROI images with truncation artifacts. Therefore, an implication of the studies is that, when truncated data are acquired with a configuration of a large geometric magnification, the BPF algorithm can be used for effective enhancement of the spatial resolution of a ROI image.