心钠素对培养人心包间皮细胞内钙离子浓度的影响

目的　探讨心纳素与人类心包间皮细胞之间的关系。　方法　分离人心包间皮细胞进行体外培养 ,用Fluo 3作为钙的指示剂 ,利用激光共聚焦显微镜测定 10 - 9mol L ,10 - 1 0 mol L ,10 - 1 1 mol L心钠素 (ANP)分别用作用于人心包间皮细胞后细胞内Ca2 (Ca2 )浓度变化。　结果　人心包间皮细胞存在细胞内Ca2 浓度的改变 ,随着ANP浓度的增加 ,细胞内Ca2 浓度出现非常明显的变化 (P <0 0 0 0 1) ;细胞内Ca2 浓度随时间变化也出现明显的变化 (P <0 0 0 0 1) ;不同时间测定的钙离子浓度与ANP浓度之间存在着交互作用 (P <0 0 0 0 1)。　结论　人心包间皮细胞存在细胞内Ca2 的改变 ;不同浓度的ANP作用于间皮细胞后引起细胞内Ca2 浓度出现明显不同的改变     

陡脉冲电场对体外人肝癌细胞内钙离子浓度的影响

为研究陡脉冲电场的凋亡效应,以人肝癌细胞系为实验对象,采用激光扫描共聚焦显微镜观察陡脉冲电场作用下细胞内钙离子浓度的变化,采用流式细胞术Annexin V检测陡脉冲电场诱导细胞凋亡.结果发现,陡脉冲电场能使肝癌细胞内钙离子浓度发生变化,变化的程度与陡脉冲电场的参数和胞外是否有钙有关,使得细胞内钙离子浓度稳态失调或大幅度振荡;流式细胞检测结果证实了陡脉冲电场能有效诱导肝癌细胞凋亡(与对照组比较,P<0.01),并且较低的电压峰值、较宽的脉冲宽度(200V/1.3μs)比较高的电压峰值、较窄的脉冲宽度(600V/100ns)能更有效地(P<0.01)诱导肝癌细胞凋亡.实验结果为陡脉冲杀伤肿瘤细胞的机制和参数选择提供了依据.     

激光对细胞内反应氧、钙离子浓度及细胞膜完整性的影响

目的 探讨在激光扫描共焦显微镜(LSCM)观测活细胞的过程中,激光对细胞内反应氧(ROS)、细胞内钙离子浓度([Ca2 ]i)和细胞膜完整性的影响.方法 用H2DCFDA、Fluo-4AM和Calcein-AM/PI分别检测488nm激光对脐静脉内皮细胞株(ECV-304)细胞内ROS、[ca2 ]i和细胞膜完整性的影响,Ultra view LCI(live cell image)共聚焦成像系统采集并分析结果.结果 激光照射后细胞内 DCF 的荧光强度迅速上升,约80s达到峰值,随后下降并逐渐回到基础水平;Fluo-4的荧光强度在70min内持续平缓地上升;Calcein 的荧光强度明显下降,少量细胞PI阳性染色.结论 488nm激光照射可引起细胞内ROS和[Ca2 ],的增加,但对细胞膜的完整性没有显著影响.     

重组人内抑素对佐剂性关节炎大鼠成纤维样滑膜细胞内钙离子稳态的影响

目的 观察重组人内抑素(rhEndestatin)对佐剂性关节炎大鼠成纤维样滑膜细胞(AA FLSs)内钙离子(Ca2+)稳态的影响,探讨rhEndomafin促进AA FLSs凋亡的离子机制,为RA药物治疗及寻找其治疗新靶点提供实验依据.方法雄性SD大鼠12只,体质量140～160 g,分为正常组(n=3)和从模型组(n=9).模型组大鼠制备从模型,体外培养AA FLSs,应用Ca2+荧光指示剂Fluo-3/AM孵育培养的细胞,激光扫描共焦显微镜检测有、无细胞外Ca2+,而rhEndestatin作用所致AA FLSs胞内Ca2+荧光强度发生动态变化,可以判断rhEndostatin对AA FLSs胞内Ca2+浓度([Ca2+]I)的影响.结果在胞外有Ca2+的情况下,rhEndostatin可引起静态AA FLS[Ca2+];快速增加,rhEndostatin作用10s后,[Ca2+];急剧增加达峰值,继之随时间缓慢下降,停止加药50 s后,[Ca2+]I尚未回复到加药前基础水平;而在无细胞外钙环境中,rhEndostatin未引起AA FLSs[Ca2+]I变化.结论 rhEndestafin可促进AA FLSs胞外Ca2+内流,引起胞内Ca2+超载,从而促进从FLSs凋亡.     

人卵母细胞体外成熟前后线粒体分布的变化

目的 研究人未成熟和成熟卵母细胞中线粒体的分布,进一步阐明卵母细胞成熟和线粒体分布的关系.方法 未成熟卵母细胞和成熟卵母细胞均用Mito Tracker Green FM染色,经多聚甲醛固定后在激光扫描共焦显微镜下观察线粒体的分布.结果 线粒体在细胞质中的分布方式可分为:周边分布、半周边分布和均匀分布.在64.10%(50/78)的GV期卵母细胞中,线粒体呈周边分布.45.16%(28/62)的MI期卵母细胞中,线粒体仍维持周边分布;呈均匀分布的卵母细胞的比例为38.71%(24/62).体外培养成熟以后,线粒体在75.47%(80/106)的卵母细胞中呈现均匀分布.与体外培养成熟的卵母细胞相比,体内成熟的卵母细胞中线粒体分布最明显的特点是胞质中央区域线粒体的浓集,荧光强度高于周边区域.结论 人卵母细胞成熟前后,线粒体出现明显的分布变化,由未成熟卵母细胞中以周边分布为主变为成熟卵母细胞中以均匀分布为主.     

硫化氢对体外大鼠肝星状细胞内Ca~(2+)浓度变化及细胞增殖的影响

目的 研究硫化氢(H2S)对大鼠肝星状细胞-T6(HSC-T6)Ca2+浓度、细胞增殖的影响及其机制. 方法 活化HSC-T6用含10%小牛1血清DMEM培养液制备为1×105个肝星状细胞(HSC)悬液.钙离子荧光探针Fluo-3/AM负载细胞后,在不同刺激条件下,利用激光扫描共焦显微镜动态扫描HSC-T6细胞内Ca2+荧光强度(FI)变化,FI表示细胞内Ca2+浓度.四唑盐比色法,观察不同浓度H2S供体--NasH对HSC-T6细胞增殖的影响. 结果 低浓度H2S(100μmol/L)明显降低HSC-T6细胞内Ca2+浓度(P<0.05),而细胞增殖增加(增殖率为116%);KATP通道阻断剂--格列本脲可阻断H2S的作用.高浓度H2S(Immol/L)刺激HSC-T6细胞内Ca2+浓度增加,但细胞增殖无明显变化(P>0.05). 结论 低浓度H2S通过激活HSC-T6细胞KATP通道降低绌胞内Ca2+浓度,可能通过调节细胞氧化应激促进细胞增殖;高浓度H2S刺激HSC-T6细胞内Ca2+浓度增加.提示H2S在肝硬化门脉高压症的发生机制中具有双重作用.     

硫化氢对体外大鼠肝星状细胞内Ca2+浓度变化及细胞增殖的影响

目的 研究硫化氢(H₂ S)对大鼠肝星状细胞-T6(HSC-T6) Ca²⁺浓度、细胞增殖的影响及其机制。 方法 活化HSC-T6用含10%小牛血清DMEM培养液制备为1×10⁵个肝星状细胞(HSC)悬液。钙离子荧光探针Fluo-3/AM负载细胞后，在不同刺激条件下，利用激光扫描共焦显微镜动态扫描HSC-T6细胞内Ca²⁺荧光强度（FI）变化，FI表示细胞内Ca²⁺浓度。四唑盐比色法，观察不同浓度H₂S供体——NaSH对HSC-T6细胞增殖的影响。 结果 低浓度H₂S（100μmol/L）明显降低HSC-T6细胞内Ca²⁺浓度（P<0.05)，而细胞增殖增加（增殖率为116%）；K_ATP通道阻断剂——格列本脲可阻断H2S的作用。高浓度H₂S（1mmol/L）刺激HSC-T6细胞内Ca₂₊浓度增加，但细胞增殖无明显变化(P＞0.05)。 结论 低浓度H₂S通过激活HSC-T6细胞K_ATP通道降低细胞内Ca²⁺浓度，可能通过调节细胞氧化应激促进细胞增殖；高浓度H2S刺激HSC-T6细胞内Ca₂₊浓度增加。提示H₂S在肝硬化门脉高压症的发生机制中具有双重作用。     

TNF-α和 LPS对体外培养血脑屏障内皮细胞胞浆内钙离子浓度的影响

目的：观察脂多糖（Lipopolysaccharid，LPS）和肿瘤坏死因子α(Tumor necrosis factor-α，TNF-α)对血脑屏障内皮细胞（Blood-brain barrier endothelial cell，BBBEC）胞浆内钙离子浓度（plasmic inner concentration of calcium，[Ca^2 ]i）的影响。方法：用Fluo-3/AM做为荧光探针对钙离子进行负载，激光扫描共聚焦显微镜观察不同浓度的LPS和TNF-α刺激下BBBEC胞浆内钙离子浓度的变化。结果：在TNF-α刺激下，单个BBBEC[Ca^2 ]i呈浓度依赖性的一过性升高。不同浓度TNF-α引起的BBBEC Ca^2 的荧光强度达高峰的时间基本一致，高峰荧光强度和荧光持续时间随TNF-α浓度的升高而增加。低浓度LPS（1μg/ml和10μg/ml）刺激细胞时，BBBEC[Ca^2 ]i无明显变化，高浓度LPS刺激细胞时，可见[Ca^2 ]i呈短暂性升高，随后下降。结论：TNF-α和LPS在极短的时间内导致BBBEC[Ca^2 ]i的升高，激活BBBEC，这一过程是缺血性脑损伤极早期的重要病理机制之一。     

口服左旋精氨酸对血小板胞浆内钙离子浓度的影响

为观察口服左旋精氨酸对正常人血小板胞浆内钙离子浓度的影响并探讨其作用机制,选择了10名至少2周内未服用任何药物,不吸烟、喝酒的健康男性志愿者.受试者服药前做1次检测,然后口服左旋精氨酸4天,前3天每天服20克,分3次服用,第4天服用1次,服7克,3小时后抽血测试.结果表明,服用左旋精氨酸后,血小板胞浆内cGMP浓度(1.91±0.20pmol/109血小板vs 2.14±0.34pmol/109血小板,P＜0.05)、血清一氧化氮代谢产物NO-3浓度(32.66±14.31μmol/L vs 49.02±9.75μmol/L,P＜0.05)升高.ADP诱导的血小板[Ca2+]i升高幅度(A/B值0.45±0.14 vs 0.32±0.09, P＜0.01)降低.研究结果表明,口服左旋精氨酸可以通过促进血管内皮细胞和血小板合成NO来降低血小板胞浆内钙离子浓度的升高,从而抑制正常人血小板的活化.     

银杏内酯B对体外培养的视网膜神经细胞内钙离子浓度和线粒体功能的影响

目的： 观察银杏内酯B对体外培养的大鼠视网膜神经细胞内钙离子浓度和线粒体功能的影响。方法: 采用体外原代培养的大鼠视网膜神经细胞,建立谷氨酸损伤的视网膜神经细胞凋亡模型,与银杏内酯B共同培养,用激光扫描共聚焦显微镜检测对视网膜神经细胞内钙离子浓度和线粒体膜电位的影响。结果: 谷氨酸（8 mmol/L）作用后,视网膜神经细胞存活率降低,细胞凋亡增加,细胞内钙离子浓度增加,线粒体膜电位下降。GB干预后,钙离子浓度降低,线粒体膜电位显著升高,细胞凋亡明显减少。结论: GB能对抗谷氨酸兴奋性毒性, 保护视网膜神经细胞,这一作用可能是通过降低细胞内钙离子浓度和升高线粒体膜电位来实现的。     

Effects of motilin on intracellular free calcium in cultured smooth muscle cells from the antrum of neonatal rats

Aim: The aim of this study was to determine the effects of motilin on [Ca²⁺]_i regulation and its underlying molecular mechanism in cultured antral smooth muscle cells (ASMCs). Methods: Antral cells were isolated and cultured from neonatal rats, and then the [Ca²⁺]_i in these cells was evaluated by calcium fluorescent probe Fluo-3/AM on a laser scanning confocal microscope. Results: We show that motilin dose-dependently increased [Ca²⁺]_i concentration in cultured ASMCs. Pre-incubation of cells with either the calcium antagonist verapamil (10⁻⁵ mol L⁻¹) or the calcium chelator Egtazic (EGTA, 0.1 mmol L⁻¹) significantly suppressed motilin (10⁻⁶ mol L⁻¹) induced [Ca²⁺]_i increase as indicated by fluorescent intensity. Interestingly, after mixing with the non-selective intracellular calcium release blocker TMB-8 (10⁻⁵ mol L⁻¹), guanosine triphosphate regulatory protein antagonist NEM (10⁻⁵ mol L⁻¹), phospholipase C (PLC) inhibitor compound 48/80 (1.2 μg mL⁻¹) and ryanodine at high concentration (10⁻⁵ mol L⁻¹), the motilin-induced [Ca²⁺]_i increase was only partially blocked. The protein kinase C inhibitor d -sphingosine (10⁻⁶ mol L⁻¹), however, did not show any inhibitory effect on motilin-induced [Ca²⁺]_i elevation. Conclusions: Our study suggests that motilin-stimulated [Ca²⁺]_i elevation in ASMCs is probably due to sustained extracellular Ca²⁺ influx and Ca²⁺ release from Ca²⁺ stores via inositol tris-phosphate receptors and ryanodine receptors. Specifically, motilin-induced [Ca²⁺]_i release is accompanied with guanosine triphosphate-binding protein-coupled receptor–PLC–inositol tris-phosphate signalling cascades.     

A primary culture system of rat olfactory bulb forming many synapses similar to intact ones and spontaneously generating synchronous intracellular calcium oscillations

Previously, several studies attempting to analyze olfactory functions using dissociated culture systems of the olfactory bulb (OB) have been reported. Reciprocal dendrodendritic synapses between secondary neurons (mitral/tufted cells) and interneurons (periglomerular/granule cells) are considered to play the most important role in signal processing in the OB. However, it is unclear whether these reciprocal synapses are formed in vitro in the same way as they are in the intact OB. Thus, we synaptologically investigated the nature of cultured OB neurons. These neurons from embryonic rats were classified into four groups based on the size of their somata and their glutamic acid decarboxylase (GAD) immunoreactivity. At 14 days in vitro, most of the neurons synchronously showed spontaneous intracellular Ca2+ oscillations that were reversibly inhibited by application of D-APV and CNQX. Moreover, the frequency of the oscillations decreased and their amplitude became larger following application of bicuculline. These results suggest functional glutamatergic synaptic coupling and inhibitory GABAergic synaptic modulation. Immunocytochemical staining revealed many dot-like products (puncta) that were immunoreactive to GAD as well as to synaptophysin surrounding the cultured neurons. These results strongly indicate the presence of GABAergic synapses. The existence of synaptic contacts in OB neuron cultures was also confirmed by electron microscopy. Two types of synapses, symmetrical and asymmetrical, were morphologically recognizable. Moreover, we could also identify peculiar synapses resembling the in vivo reciprocal dendrodendritic synapses. The use of these primary culture systems will facilitate the elucidation of mechanisms underlying olfactory functions.     

超氧阴离子自由基对大鼠肝卵圆细胞胞内自由钙浓度的影响

采用激光共聚焦扫描显微镜,观察黄嘌呤黄嘌呤氧化酶反应系统（Ｘ／ＸＯ）生成不同浓度的超氧阴离子自由基（Ｏ２）致培养的大鼠肝卵圆细胞（ＷＢ细胞）胞质内钙浓度的变化,结果发现：仅小剂量的Ｏ２引起胞质内钙浓度升高,约３０Ｓ后达到峰值,６０ｓ后恢复正常。部分细胞观察到数次钙浓度间断升高、幅度逐渐下降的现象。超氧化物歧化酶（ＳＯＤ）可抑制此变化,过氧化氢酶（ＣＡＴ）无效果,细胞在无钙液中观察仍出现钙峰,但受     

地塞米松对大鼠胸膜间皮细胞水通道蛋白1表达的调节

 目的：观察胸膜间皮细胞水通道蛋白1（AQP-1）的表达及地塞米松（Dex）对其表达的影响，为进一步研究胸水治疗的机制提供实验依据。方法:体外培养大鼠胸膜间皮细胞，细胞鉴定后，采用免疫细胞化学、RT-PCR方法检测AQP-1表达；应用Western blotting检测以不同浓度Dex（10^-8、10^-7、10^-6、10^-5、10^-4 mmol/L）处理细胞 24 h 及以10^-4 mmol/L Dex处理细胞 6 h、12 h、24 h、36 h、48 h、72 h后AQP-1表达情况。结果:发现胸膜间皮细胞存在AQP-1表达， 10^-8、10^-7、10^-6、10^-5、10^-4 mmol/ L Dex干预胸膜间皮细胞 24 h 后，AQP-1蛋白表达量(积分吸光度)分别为755.04±19.81、843.72±19.41、862.96±26.53、694.80±32.00、938.08±13.32，分别高于正常对照组（372.90±16.46） 2.02、2.26、2.31、1.86、2.52倍 (P<0.01)，AQP-1表达升高与地塞米松浓度无关；以10-4 mmol/L Dex干预细胞 6 h、12 h、24 h、36 h、48 h、72 h 后，AQP-1蛋白表达量分别为：554.14±23.57、917.78±38.62、1 587.20±61.22、1 322.09±28.65、918.40±26.62、1 117.60±51.32，分别高于正常对照组（495.91±23.12）1.12、1.85、3.20、2.67、1.85、2.25倍(P<0.01)，AQP-1表达与地塞米松作用时间有关。结论:胸膜间皮细胞存在AQP-1表达，地塞米松对胸膜间皮细胞AQP-1表达有明显的增强性调节作用，具有时间依赖性。     

镁对大鼠缺氧再给氧心肌细胞内游离钙的影响

目的和方法：用ＡＣＡＳ５７０粘附式细胞仪，以荧光素染色法观察镁（Ｍｇ２＋）对体外培养乳鼠心肌细胞内游离钙（Ｃａ２＋）的影响及对缺氧再给氧时细胞内Ｃａ２＋作用。结果：细胞外Ｍｇ２＋降至０３ｍｍｏｌ·Ｌ－１，细胞内Ｃａ２＋荧光强度上升速度加快，达到稳定所需时间延长，出现Ｃａ２＋振荡曲线。增加Ｍｇ２＋浓度可使细胞内Ｃａ２＋降低。Ｍｇ２＋还可以显著减少缺氧再给氧时细胞内Ｃａ２＋，Ｐ＜００１。结论：细胞外低Ｍｇ２＋可导致细胞内Ｃａ２＋增加，Ｍｇ２＋有维持正常心肌细胞内Ｃａ２＋稳定性及拮抗缺氧再给氧时细胞内Ｃａ２＋超载作用     

Distribution of calretinin immunoreactivity in the mouse dentate gyrus

Calretinin containing elements were visualized with immunocytochemistry in the adult mouse dentate gyrus (DG). In the ventral DG calretinin immunoreactive (CR-IR) large multipolar cells were clustered; they extended between two and four thick cylindrical dendrites which further branched into several thinner processes. Characteristic grape like spiny appendages were occasionally observed on these thick and thinner dendritic processes. On the basis of these structural features these large CR-IR cells were identified as hilar mossy cells. At the supragranular zone a dense CR-IR band was seen, where numerous CR-IR punctae and fibers were packed tightly among putative granule cell dendrites. In the granule cell layer, especially at the dorsal DG, numerous faintly CR-IR cells were located at the interface with the hilus. They were triangular in shape and neither calbindin D28k nor GABA positive, but were immunoreactive for highly polysialylated neural cell adhesion molecule (NCAM-H) and thus considered as newly generated neurons. In the molecular layer CR-IR cells were also scattered; they were mainly located near the pial surface and the hippocampal fissure, small in size, ovoid in shape and usually gave rise to one very thin axon like and one thin cylindrical dendritic process. These cells were assumed to be Cajal-Retzius cells. Throughout the layers, that is, the molecular layer, the granule cell layer and the hilus, CR-IR multipolar and/or fusiform cells were encountered. They resembled those reported in the rat DG in their structural features and usually extended smooth or varicose or sparsely spiny dendritic processes; some of them were confirmed to be GABA-like immunoreactive and/or glutamic acid decarboxylase immunoreactive. The present study showed that CR immunoreactivity in the mouse DG differed significantly from that in the rat and monkey dentate gyri reported previously.     

Effects of asbestos and man-made vitreous fibers on cell division in cultured human mesothelial cells in comparison to rodent cells

We report the effects of chrysotile and crocidol-ite asbestos, and glass and rock wool fibers (man-made vitreous fibers, MMVF) on the induction of binucleate cells in vitro. The response of human mesothelial cells (target cells in fiber carcinogenesis) and rodent cells was compared. Human primary mesothelial cells, MeT-5A cells (an immortalized human mesothelial cell line), and rat liver epithelial (RLE) cells were exposed to asbestos and MMVF samples of similar size range. Milled glass wool, milled rock wool, and titanium dioxide were used as non-fibrous particle controls. All four fiber types caused statistically significant increases in the amount of binucleate cells in human primary mesothelial cells and MeT-5A cells (in the dose range 0.5–5.0 ug/ cm²). Chrysotile and crocidolite asbestos were more effective (1.3–3.0-fold increases) than thin glass wool and thin rock wool fibers (1.3–2.2–fold increases). However, when the fiber doses were expressed as the number of fibers per culture area, the asbestos and MMVF appeared equally effective in human mesothelial cells. In RLE cells, chrysotile was the most potent inducer of binucleation (2.9–5.0-fold increases), but the response of the RLE cells to crocidolite, thin glass wool, and thin rock wool fibers was similar to the response of the human mesothelial cells. No statistically significant increases in the number of bi- or multinucleate cells were observed in human primary mesothelial cells or RLE cells exposed to the non-fibrous dusts. In MeT-5A cells exposed to 5 ug/cm² of milled glass wool and milled rock wool, as well as in cultures exposed to 2 and 5 ug/cm² of TiO₂, significant increases were, however, observed. Our results show that rodent cells respond differently to mineral fibers than human cells. The results also add evidence to the suggested importance of disturbed cell division in fiber carcinogenesis. © 1995 Wiley-Liss, Inc.     

Adaptation of a preembedding electron microscopic in situ hybridization for detection of the telomere region in human interphase nuclei

The in situ hybridization (ISH) method is generally used in light microscopy but not in electron microscopy. We investigated whether the ISH method can be applied to electron microscopy (EM) by a preembedding method using human lymphocyte nuclei as a material. In addition, we also present some data from fluorescence in situ hybridization (FISH) using the same DNA probe. We indicate the suitability of preembedding EM-ISH to isolated cells.     

临产前后子宫平滑肌细胞内游离钙含量的变化

目的:探讨临产前后子宫平滑肌细胞内游离Ca²⁺含量变化。方法:应用特异性Ca²⁺荧光指示剂Fluo-3AM,对19例未临产和23例临产足月妊娠孕妇,剖宫产子宫下段平滑肌细胞进行负载,结合激光扫描共聚焦显微镜测定子宫平滑肌细胞内游离Ca²⁺分布状态及其浓度变化规律。结果:Ca²⁺在子宫平滑肌细胞胞浆内呈弥漫分布的颗粒状红色荧光物质,在未临产平滑肌细胞中分布和荧光强度均较弱,在临产子宫平滑肌细胞中明显增强。在未临产和临产子宫平滑肌[Ca²⁺]i分别为(35±8.1)nmol/L和(75±7.3)nmol/L,二者静息状态下子宫平滑肌[Ca²⁺]i差异显著(P＜0.05)。结论:分娩前后子宫平滑肌细胞内游离Ca²⁺含量的变化,可能为宫缩发生发展过程复杂的重要事件和分子机制之一。     

Calcifying Odontogenic Cysts Associated with Odontomas: Confocal Laser Scanning Microscopy Analysis of 13 Cases

The so-called calcifying odontogenic cyst (COC) represents a heterogeneous group of lesions that exhibit a variety of clinico-pathologic features. It is an uncommon lesion and represents less than 2% of all odontogenic cysts and tumors. Recently, these lesions have been reclassified as calcifying cystic odontogenic tumors (CCOT), according to the new World Health Organization (WHO) classification. CCOT are frequently found in association with, or containing areas histologically identical to, various types of odontogenic tumors, such as complex/compound odontomas. This work analyzed clinical and histological data deriving from 13 patients affected by CCOT associated with odontomas. Moreover, a confocal laser scanning microscope (CLSM) analysis was undertaken to further a better understanding of the nature of this peculiar lesion.