首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
应用真彩色医学图像分析技术, 对90 例甲状腺肿瘤(其中甲状腺腺瘤10 例, 不典型腺瘤15 例,乳头状腺癌25 例, 滤泡癌15 例, 髓样癌15 例, 未分化癌10 例) 细胞核DNA含量进行了分析。结果显示,甲状腺腺瘤组与各型甲状腺癌比较均有显著性差异(P< 001),甲状腺腺瘤组同不典型腺瘤组比较无统计学意义(P> 005)。甲状腺癌随组织分化程度的不同, DNA 含量明显增加, 多为高倍异倍体细胞, DNA直方图明显右移, 峰值主要位于≥5C处; 甲状腺腺瘤组DNA含量较低, 多为低倍整倍体细胞, DNA 直方图峰值位于2C- 4C处; 不典型腺瘤组DNA含量介于上述二者之间, DNA 直方图逐渐右移。表明DNA倍性程度与肿瘤的增殖程度呈正相关, 高倍异倍体细胞随肿瘤恶性程度的增高而增多。作者认为DNA原位图像定量分析可为甲状腺肿瘤的诊断、分级及早期发现癌变趋势提供一个可靠的参考指标  相似文献   

3.
朱顶红花粉管中营养核和生殖细胞位置的变换   总被引:2,自引:1,他引:2  
用一种改进的FITC微管蛋白免疫荧光和DAPI双定位的技术,在紫外光激发下能同时显示花粉管中的生殖细胞(GC)和营养核(VN)。在朱顶红(Am aryllis vittata Ait.)花粉萌发的最初1—2 小时内,GC和VN 都有可能从花粉粒先进入花粉管。然而,在GC分裂前VN 总是变为在GC之前和接近花粉管顶端的位置。因此,在生殖细胞先进入花粉管的情况下,VN必然越过GC而使位置发生变换。根据观察的图象可以总结出三种基本的过程。1. 在萌发后约2小时,营养核位于GC后端延伸的细胞质附近,形成暂时的物理联结。2.VN 进一步向前更快地移动,以致整个VN 与GC并列和紧靠,它们常相互扭结在一起。3.VN 越过GC,并变为高度延长,它的后端常部分地插入生殖细胞的细胞质中。观察结果表明:VN和GC通过花粉管时移动的速度是明显不同的。这种速度的差别可以认为存在各自独立运动的机制,以及VN 和GC本身结构的差别,为它们在花粉管中的移动提供各自运动的动力  相似文献   

4.
AgNORs异型颗粒在乳腺癌细胞核中的观察分析   总被引:1,自引:0,他引:1  
本文报道了核仁组成区嗜银蛋白(AgNORs)在乳腺癌细胞核中的一组异型颗粒——字母样结构“CEIJRSTURYX”等,乳腺良性病变无此结构。研究结果表明,字母样结构在浸润性导管癌中多见,在乳头状癌中未见。结合乳腺癌的临床分期分析,临床分期越高,有字母样结构的乳腺癌所占比分也越高。同时,有字母样结构的乳腺癌组其AgNORs含量和颗粒形态的异型性均明显高于无字母样结构的乳腺癌组。在讨论中认为,AgNORs字母样结构对鉴别诊断乳腺癌可能有一定的形态学参考价值  相似文献   

5.
6.
A desoxyribose nucleoprotein complex, which we have referred to as a chromosin, has been prepared from a great variety of cells, mainly animal but also plant and bacterial. A chromosin is derived from the cell nucleus. In the course of preparation precautions have been taken to prevent contamination by cytoplasmic constituents. To assure the nuclear origin of all components of chromosin, nuclei have in several instances been isolated before extraction was begun. Because of the precautions taken, chromosins do not contain detectable quantities of ribose nucleoproteins; but, incidentally, extraction of ribose nucleoproteins, free of desoxyribose compounds, has also been described in this paper. A typical chromosin contains 3 components: desoxyribose nucleic acid, histone, and non-histone protein. The nucleic acid, being highly polymerized, is exceedingly viscous when dissolved and fibrous when precipitated. Histone and non-histone protein differ from each other in a number of ways, of which one of the most definite is that whereas a histone contains no more than traces of tryptophane, the non-histone protein of chromosin contains nearly 1 per cent of tryptophane. In neutral physiological saline both proteins can combine with nucleic acid. With the isolation of chromosins from so many different kinds of cells, it can now be seen that (contrary to the view expressed by Kossel) histones are present in most animal cells and at least in some plant and bacterial cells. Chromosin prepared from the Type III pneumococcus is active in transforming the type of a pneumococcus culture. It has been pointed out that it is not yet known whether or not protein is a necessary constituent of the transforming agent. To extract chromosin from a cell M NaCl is used. When dissolved in M NaCl the nucleic acid and histone components of a chromosin are to a considerable extent dissociated. They are not dissociated when the chromosin is dissolved in 0.02 M NaCl, but in this medium a partial depolymerization of the nucleic acid occurs. A chromosin should certainly not be considered to be a definite chemical compound. It is a complex extracted from chromatin, which is itself a complicated nuclear structure. And in the course of extraction, it need hardly be said, the structure of chromatin has been considerably changed. To avoid complications it has been considered an advantage in this work to begin with isolated nuclei, and it would clearly be a further simplification to begin chemical procedures only after the chromosomes themselves have been isolated. This is now being accomplished, and it is found that the methods described in this paper are of value in learning how the substances present in a chromosin are put together in a chromosome.  相似文献   

7.
The suprachiasmatic nucleus (SCN) of the hypothalamus is the site of the pacemaker that controls circadian rhythms of a variety of physiological functions. Data strongly indicate the majority of the SCN neurons express self-sustaining oscillations that can be detected as rhythms in the spontaneous firing of individual neurons. The period of single SCN neurons in a dissociated cell culture is dispersed in a wide range (from 20h to 28h in rats), but that of the locomotor rhythm is close to 24h, suggesting individual oscillators are coupled to generate an averaged circadian period in the nucleus. Electrical coupling via gap junctions, glial regulation, calcium spikes, ephaptic interactions, extracellular ion flux, and diffusible substances have been discussed as possible mechanisms that mediate the interneuronal rhythm synchrony. Recently, GABA (γ-aminobutyric acid), a major neurotransmitter in the SCN, was reported to regulate cellular communication and to synchronize rhythms through GABAA receptors. At present, subsequent intracellular processes that are able to reset the genetic loop of oscillations are unknown. There may be diverse mechanisms for integrating the multiple circadian oscillators in the SCN. This article reviews the knowledge about the various circadian oscillations intrinsic to the SCN, with particular focus on the intercellular signaling of coupled oscillators. (Chronobiology International, 18(3), 371–387, 2001)  相似文献   

8.
Observations have been made of ultrastructural modifications induced in the nuclei of differentiating amphibian embryonic cells cultured in the presence of Actinomycin D. Of particular interest are regions within the nucleus (regions otherwise rather empty) containing loose groupings of uniform threads having a diameter of around 200 A. These threads have been observed in continuous lengths up to 0.5 µ, and appear to be composed of subfilaments. It is suggested, after taking account of some recent work on lampbrush chromosomes, that these threads are lengths of uncoiled chromosome in a condition of heterosynthetic inhibition. It is further suggested that active and inactive portions of the genome may be distinguishable by the facility with which they can be induced to undergo this ultrastructural modification.  相似文献   

9.
THE PERMEABILITY OF THE AMPHIBIAN OOCYTE NUCLEUS, IN SITU   总被引:4,自引:4,他引:4       下载免费PDF全文
Ultralow temperature radioautography, suitable for the quantitative localization of diffusible solutes, was used to study the permeability of the nuclear envelope in the intact amphibian oocyte Sucrose-3H solutions were injected into mature oocytes, in volumes of 0 016–0 14% of that of the cell, and the subsequent movement of the solute was recorded. The resultant radioautographs show diffusion gradients in the cytoplasm and nucleus, and concentration gradients across the nuclear envelope Analysis of these gradients discloses that the nuclear envelope is as permeable as a comparable structure composed of cytoplasm, and is about 108 times more permeable than the oocyte plasma membrane The diffusion coefficient of sucrose in cytoplasm is 2 x 10-6 cm2/sec, or about one-third its diffusivity in pure water. This reduction can probably be accounted for by an effective lengthening of the diffusional path because of obstruction by cytoplasmic inclusions. The nuclear: cytoplasmic sucrose concentration ratio at diffusional equilibrium is about 3 05, or 1.6 times as great as expected from the water content of the two compartments This asymmetry is attributed to an unavailability of 36% of the cytoplasmic water as solvent Finally, sucrose entry into oocytes from a bathing solution was monitored by whole cell analysis and radioautography. These and the microinjection results are consistent with a model in which sucrose entry into the cell is entirely limited by the permeability of the plasma membrane. The results are inconsistent with cell models that hypothesize a short-circuit transport route from the extracellular compartment to the nucleus, and with models in which cytoplasmic diffusion is viewed as limiting the rate of solute permeation.  相似文献   

10.
11.
Despite significant advances in our understanding of the roles of the cytoskeleton and matrix receptors in cell locomotion, derived largely fromin vitrostudies on the movement of epithelial cell sheets and isolated cells, the mechanism of epithelial cell migration in the adult intestine remains an enigma. The primary function of the epithelial cell cytoskeleton seems to be in the maintenance of the apical region of the epithelium facing the gut lumen. There we find the brush border, with its associated enzymes, and the intercellular adhesion complexes that give the epithelium its cohesiveness and its barrier function. Curiously, there is little in the way of an organized cytoskeleton in the basal region of the epithelium adjacent to the basement membrane on which the epithelium is presumed to migrate. In this short review, I focus on what is known about epithelial migration from our understanding of the structure of the epithelium and from studies on wound healing, and indicate some avenues for future study.  相似文献   

12.
潘培森  张义声 《生理学报》1991,43(2):184-188
实验在氯醛糖和尿酯混合麻醉的大鼠上进行。在内脏大神经上记录刺激同侧前庭神经进入脑干处的交感反应。电刺激前庭神经可在同侧内脏大神经引出—明确的叠加反应,其平均潜伏期为45.8±6.98ms,时程为55.21±5.35ms。增加刺激强度,反应幅度也增加,但潜伏期不变。用前庭内侧核(NVM)的片层场电位作为指标并选择其相位倒转处作刺激点,可在同侧内脏大神经记录到潜伏期为32ms 的叠加反应,而同一动物刺激前庭神经入脑处时内脏大神经反应的潜伏期为43ms。在 NVM 头端损毁后,此前庭-交感反应明显减小,再损毁尾端 NVM 后,此反应消失。损毁 Deiters 核对前庭-交感反应无影响。这些结果表明 NVM在内脏大神经记录到的前庭-交感反应中是一重要的中继站。  相似文献   

13.
猫外侧膝状体年龄相关性形态学变化   总被引:1,自引:0,他引:1  
目的比较青年猫与老年猫外侧膝状体(lateral geniculate nucleus,LGN)神经元及γ-氨基丁酸(gama-aminobutyric acid,GABA)能神经元的年龄相关性变化,探讨老年个体视觉功能衰退的相关神经机理。方法Nissl染色示猫外侧膝状体分层结构(A、A1、C3层)及神经元,免疫组织化学法示GABA免疫阳性神经元。光镜下观察、拍照,Nissl染色切片测量外侧膝状体各层厚度、神经元胞体直径并计数神经元数量;免疫组化染色切片测量外侧膝状体各层中GABA阳性神经元胞体直径并计数GABA阳性神经元数量。结果青年猫及老年猫外侧膝状体各层厚度、神经元数量及胞体直径无明显改变(P>0.05);与青年猫相比,老年猫外侧膝状体各层中GABA阳性神经元数量及胞体直径均有不同程度的显著下降(P<0.01),且GABA免疫阳性反应减弱。结论在动物个体衰老进程中,外侧膝状体总体神经元保持相对稳定可能对老年个体维持视觉功能具有一定意义;老年个体外侧膝状体GABA能神经元对视觉信息传递及整合过程的抑制性调节功能削弱,可能是外侧膝状体水平上导致老年个体视觉功能衰退的原因之一。  相似文献   

14.
在猫孤束核(NTS)中有许多吸神经元而只有极少呼神经元。这个事实加上其它一些证据,使有些作者认为呼吸节律发生的交互抑制模型是不适当的。但细胞内记录的工作表明在呼和吸神经元均有交替出现的超极化和去极化,说明交互抑制确实存在。另一些人在 NTS 之外的 B(?)tzinger 复合体找到一群呼神经元,其轴突伸至 NTS 的吸神经元区。但 NTS 只投射到闩部后的腹外侧区另一群呼神  相似文献   

15.
钙调素对细胞周期的调节   总被引:1,自引:0,他引:1  
RC3细胞是一种用真核表达载体1~(CaM)转染NIH 3T3细胞建成的可调钙凋素(Calmodulin,CaM)高表达细胞模型。通过分子杂交及蛋白免疫印迹方法证实在地塞米松(Dexamethasome,DXM)作用下,RC3细胞可高表达CaM。CaM的过表达使G_1期细胞减少,S期细胞增加;CaM拮抗剂三氟拉嗪(trifluoperazine,TFP)则使G_1期细胞增加,S期细胞减少。高表达CaM使细胞分裂指数提高,G_2期细胞减少,有丝分裂前期细胞增加,M中期细胞比例下降。而TFP处理则使分裂指数下降,G_2期细胞增加,M前期细胞减少,M中期细胞增加。实验结果表明CaM在G_1/S、G_2/M和M中期/M后期3个位点上对细胞周期进行调控;通过加速G_1至S期,G_2至M期和M中期至M后期的进程,使细胞倍增时间缩短,促进细胞增殖。本工作表明,RC3细胞作为CaM表达可调细胞模型,是研究细胞周期调控的有力工具。  相似文献   

16.
It is proposed that elongation of the nucleus in spermatids of Marchantia results from interaction between its membranous envelope and microtubules of the spermatid's cytoskeleton. The nucleus may be drawn out in two directions along microtubules until forces attracting the nucleus to them are balanced by forces resisting envelope distortion. Condensation of nuclear chromatin into fibrils of uniform diameter and probable shaping of the nucleus by blebbing of its envelope occur together before elongation is complete. The nucleus becomes crescent shaped and it is prolonged distally into a chromatin-free diverticulum. In accord with their distribution along the axis of the nucleus, chromatin fibrils are compacted together forming a cone-like rod of chromatin which narrows anteriorly and extends distally to the tip of the preexisting diverticulum. Elongation and shaping of the nucleus influence the distribution of its chromatin and thus its ultimate morphology. Coiling of the nucleus is related to a reduction of spermatid cytoplasm during maturation.  相似文献   

17.
大鼠延髓外周橄榄腹外侧核在中枢化学感受中的作用   总被引:1,自引:0,他引:1  
田国锋  钱梓文 《生理学报》1995,47(4):327-335
本工作采用微量注射、电损毁、电刺激和微电泳的方法,探讨了大鼠延髓外周橄榄腹外侧核(LVPO)的否真正参与中枢化学感受功能。实验在38只雄性SD大鼠上进行。结果表明:(1)微量注射酸化人工脑脊液于LVPO可引起隔神经放电活动明显加强。(2)微电泳给予H^+对LVPO的自发放电单位主要引起兴奋反应,微电泳给予H^+引起兴奋反应的部分单位也可被腹外侧表面微量注射酸化人工CSF所兴奋。(3)损毁LVPO后  相似文献   

18.
罗茀荪 《生理学报》1988,40(1):1-12
家兔的视觉系统有其特色,其外膝体的解剖和生理特性与猫的情况有所不同。本文综述了家兔外膝体神经元回路研究的进展,特别是关于返回抑制回路的组成和机能意义为研究进展,并以此为例说明丘脑-大脑皮层的复杂相关关系。  相似文献   

19.
分别向杏仁内侧核(MAN)内微量注射去甲肾上腺素(NA)或神经肽Y(NPY)。NA引起血压升高,心率加快;而NPY引起血压降低,心率减慢。如果注入不能改变血压的小剂量NPY,则可抑制NA引起的升压作用,反映NPY与NA共同参与心血管活动的中枢性调节过程。向MAN中注射NPY后血中NA的含量也相应降低,表明在MAN中注射NPY引起的血压、心率反应是通过降低血浆中NA含量而实现的。  相似文献   

20.
家兔延髓面神经后核内侧区在吗啡抑制呼吸中的作用   总被引:1,自引:0,他引:1  
实验在麻醉、切断颈迷走神经、肌肉麻痹和人工通气的家兔上进行。静脉注射吗啡4mg/kg能显著地抑制呼吸,主要是使呼吸频率降低和每分钟膈神经活动减少。如果先向延髓面神经后核内侧区(mNRF)注射1μg/1μl纳洛酮,可大部分阻断静脉注射吗啡引起的呼吸抑制。向一侧mNRF注射10μg/1μl吗啡能显著地抑制呼吸,两侧注射则产生呼吸暂停。先向两侧mNRF注射1μg/1μl纳洛酮,可完全阻断mNRF注射吗啡引起的呼吸抑制。结果说明mNRF存在阿片受体,并在静脉注射吗啡引起的呼吸抑制中起重要作用。本工作还为mNRF在发生和维持呼吸节律中的重要作用提供了新的证据。  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号