Pharmacological Characterization of Bradykinin Receptors Coupled to Phosphoinositide Turnover in SV40-Immortalized Human Trabecular Meshwork Cells

This study sought to pharmacologically characterize bradykinin receptors on SV40-immortalized human trabecular meshwork (HTM3) cells. Phosphoinositide (PI) turnover studies were conducted using [³H]myo-inositol-labeled HTM3 cells and anion exchange chromatography to quantify [³H]inositol phosphates generated in response to bradykinin (BK) and various BK analogs. The blockade of these responses was studied using two potent and receptor-subtype selective antagonists. BK and T-kinin (Ile-Ser-BK; TK) induced a 4.2–4.4 fold stimulation of PI turnover above base levels at 1–10 μM. Several other peptides unrelated to BK, including angiotensin II, endothelin, cholecystokinin, bombesin and peptide YY tested at 1–10 μMwere essentially inactive. The molar potencies (EC₅₀) of BK, TK and close analogs were: BK=4.5±0.5 nM(n=6), Lys-BK=6.5±0.7 nM(n=3), TK=38.8±6.6 nM(n=8), Met-Lys-BK=41.5±13.4 nM(n=4), Des-Arg⁹-BK=2093±626 nM(n=4). All the latter BK-related peptides>were full agonists. The actions of BK and TK were potently and competitively antagonized by Hoe-140 (molar potency=0.6–1 nM;pA₂n=8.97–9.21,n=3–4) and byD-Arg⁰[Hyp³,-Thi^5,8,-DPhe⁷]-BK (molar potency=251 nM;-log potency, pK_b=6.6), two selective B₂-type BK antagonists. In conclusion, rank order of potency of BK agonists and the blockade of BK- and TK-induced PI turnover by the selective antagonists are consistent with the classification of the BK receptors on HTM3 cells as the B₂-receptor subtype.     

Effects of Nitric Oxide on Proliferation and Apoptosis of Cultured Bovine Trabecular Meshwork Cell

Nitric Oxide (NO) shows a dualism in thepathogenesis of glaucoma:in one side,NO can im-prove outflow facility of aqueous humor and dropintraocular pressure (IOP) ;on the other side,ithas direct toxic effect on retinal ganglion cell[1] .Our preveious studies demonstrated,in some ex-tent,pressure could induce inducible nitric oxidesynthase(i NOS) m RNA expression,so to increase NOS synthesis and NO level[2 ] .In this experimentwe discussed the effects of NO on the proliferationand apopto…     

A Bayesian approach to subvoxel tissue classification in NMR microscopic images of trabecular bone

NMR microscopy is currently being used as an investigational tool for the evaluation of micromorphometric parameters of trabecular bone as a possible means to assess its strength. Since, typically, the image voxel size is not significantly smaller than individual trabecular elements, partial volume blurring can be a major complication for accurate tissue classification. In this paper, a Bayesian segmentation technique is reported that achieves improved subvoxel tissue classification. Each voxel is subdivided either into eight subvoxels twice the original resolution, or up to four subvoxels along the transaxial direction and the subvoxels optimally classified as either bone or marrow. Based on a statistical model for partial volume blurring, the likelihood for the number of marrow subvoxels in each voxel can be computed on the basis of its measured signal. To resolve the ambiguity of the location of the marrow subvoxels, a Gibbs distribution is introduced to model the interaction between the subvoxels. Neighboring subvoxel pairs with the same tissue label are encouraged, and pairs with distinct labels are penalized. The segmentation is achieved by maximizing the a posteriori probability of the label image using the block ICM (iterative conditional mode) algorithm. The potential of the proposed technique is demonstrated in real and synthetic NMR microscopic images.     

基于反向滤波器的倒谱法估计平均骨小梁间距

目的 探讨用改进的倒谱方法估计平均骨小梁间距(mean trabecular bone spacing,MTBS)的可行性.方法 提出了一种基于反向滤波器的改进的倒谱分析方法用于估计MTBS,并将该方法应用于仿真及离体牛胫骨松质骨中的实验信号.结果 改进的倒谱方法能有效减少超声换能器脉冲响应和组织散射特性对倒谱的干扰,而且实现简单,计算量小.结论 相比于传统的倒谱方法,改进的倒谱方法在估计MTBS时, 对弥散散射和噪声有更强的鲁棒性,因此估计MTBS的精度更高.     

Microstructure of trabecular bone in a mouse model for down syndrome

Down syndrome (DS) is caused by trisomy of human chromosome 21 (Hsa21) and results in a suite of dysmorphic phenotypes, including effects on the postcranial skeleton and the skull. We have previously demonstrated parallels in the patterns of craniofacial dysmorphology in DS and in the Ts65Dn mouse model for DS. The specific mechanisms underlying the production of these changes in craniofacial shape remain unknown. High‐resolution computed tomography scan data were collected for the presphenoid bone of euploid and aneuploid mice. Three‐dimensional morphometric parameters of trabecular bone were quantified and compared between euploid and aneuploid mice using nonparametric statistical tests. Aneuploid presphenoid bones were smaller than those of their euploid littermates and had lower bone volume fraction and fewer, more rod‐like trabeculae. The differences in cancellous bone structure suggest that bone development, perhaps including bone modeling and remodeling, is affected by aneuploidy. These differences may contribute to the observed dysmorphology of skull and postcranial skeletal phenotypes in DS. Anat Rec, 2007. © 2007 Wiley‐Liss, Inc.     

The skeleton as a unique environment for breast cancer cells

Bone is a favored location for several cancer metastases especially breast, prostate and myeloma. This review evaluates various properties of the skeleton that contribute to its successful colonization by breast cancer cells. The first consideration is the unique aspects of the vasculature of metaphyseal bone, which may account for the initial lodging of breast cancer cells in specific regions of the skeleton. Metasphyseal bone, found at the ends of long bone, in ribs and in vertebrae, is comprised of trabecular bone interspersed with marrow and a rich vasculature. The chemotactic factors that arise from bone marrow and bone cells are discussed in terms of cancer cell migration out of the vasculature and entry of cancer cells into the marrow cavity. Once the breast cancer cells have migrated into the metaphysis, they interact both directly and indirectly with bone cells and other cells in the marrow. As tumor growth progresses, functional bone cells are lost, most likely through apoptosis. This revised version was published online in July 2006 with corrections to the Cover Date.     

人眼小梁细胞体外表达表皮生长因子mRNA和表皮生长因子受体

目的 了解培养的小梁细胞分泌表皮生长因子（ｅｐｉｄｅｒｍａｌ ｇｒｏｗｔｈ ｆａｃｔｏｒ,ＥＧＦ）及细胞膜上表皮生长因子受体（ｅｐｉｄｅｒｍａｌ ｇｒｏｗｔｈ ｆａｃｔｏｒ ｒｅｃｅｐｔｏｒ,ＥＧＦＲ）的情况。方法 进行人眼小梁细胞体外培养。用ＥＧＦ ｃＤＡＮ探针,α＾－３２ｐ同位素标记及斑点杂交放射自显影法,检测小梁细胞分泌ＥＧＦｍＲＮＡ的情况。结果 人眼小梁细胞体外培养成功。免疫组化染色显示小     

压力对体外培养牛眼小梁细胞的影响

目的 观察压力对小梁细胞的影响。方法 对体外培养牛眼小梁细胞施以不同程度的压力,用倒置相差显微镜、光镜、电镜观察细胞形态结构及吞噬功能的变化。结果 细胞承受２．００ｋｐａ（１ｋｐａ＝７．５ｍｍＨｇ）、２．６７ｋｐａ压力４８小时,各项指标与对照组比较,差异无显著性。４．００ｋｐａ２４小时,细胞形态结构有轻度的损伤,吞噬功能有轻度下降。当压力进一步增加,时间更加延长后,细胞的损伤也更重。结论小梁细胞只     

地塞米松对小梁细胞粘附及吞噬功能的影响

目的：探讨地塞米松对小梁细胞的粘附及吞噬功能的影响。方法：不同浓度地塞米松(10^-7M，10^-6M，10^-5M)处理体外培养的牛眼小梁细胞3d，消化、漂洗后加入用不同的细胞外基质(Extracellular matrix，ECM)包被的培养板中，37℃孵育90min后．采用甲基噻唑基四唑(Methyl thiazolyl tetrazolium，MW)法测定各组吸光度值反应粘附细胞的量；另外，以乳胶微球为标记，观察不同浓度的地塞米松对小梁细胞吞噬功能的影响。结果：与对照组比较，三种浓度的地塞米松均对小梁细胞与ECM粘附有抑制作用．且呈浓度依赖性；对小梁细胞的吞噬功能亦呈现浓度依赖性抑制作用。结论：地塞米松对小梁细胞的粘附及吞噬功能有抑制作用，抑制小梁细胞的粘附及吞噬功能可能是皮质类固醇性青光眼的发病原因之一。     

不同植入物在非穿透小梁手术的临床观察

目的探讨不同植入物在非穿透小梁手术(NPTS)中治疗开角型青光眼的临床疗效。方法将40例(54眼)原发开角型青光眼随机分为A、B、C三组,每组均为18眼。A组:NPTS+HealonGV植入。B组:NPTS+保存羊膜植入。C组:NPTS+透明质酸钠生物胶(SK-GEL)植入。术中全部眼联合丝裂霉素C及可调缝线,观察术后眼压、视力、滤过泡、前房、视野等。结果随访6～18个月,平均(9.32±4.81)个月,手术成功率:A组55.56%,B组88.89%,C组94.44%,B、C组与A组比较差异有统计学意义(P<0.05),而B和C两组间差异无统计学意义(P>0.05)。三组患者无前房变浅、炎症、脉络膜脱离、视力下降等并发症。结论NPTS植入物中SK-GEL及羊膜最好,HealonGV次之,羊膜更经济。