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61.
During regeneration of the neural ganglion in Ciona intestinalis, the pattern of reappearance of some peptidergic cells is similar to the ontogenetic patterns exhibited by these cell types during normal post-metamorphic development. Using a specific antiserum to gamma-aminobutyric acid (GABA), we describe here the appearance of GABA-ergic cells in Ciona during both post-metamorphic development and regeneration of the neural ganglion following total ablation. Post-metamorphic animals were divided into the categories: 1, 3–5, 6–10, 11–15 and 23–27 mm in body length. Regeneration was monitored at 12, 15, 18, 21, 28 and 56 days post ablation. The first appearance of GABA-like immunoreactive cells during normal development were at the 3 to 5-mm stage where they were seen as discrete cells, without processes, evenly distributed in the cortical region throughout the ganglion. Fibres were first seen at the 6 to 10-mm stage. As development proceeded, GABA-like immunoreactive cells became more concentrated near the nerve root exits and along the dorsal rind of the ganglion. In regenerating ganglia, GABA was first detected at 18–21 days post ablation, in cells that lacked any obvious processes and that were distributed in all regions of the ganglion. At 28 days post ablation, processes could be detected in the neuropile, and after 56 days GABA cells were found predominantly in the same regions as in the normally developing adult ganglion. Although the overall pattern reflects that in a normal adult, a few differences were detectable. For example, rather more GABAergic cells were concentrated ventrally in the ganglion close to the neural gland.  相似文献   
62.
Cellular properties and modulation of the identified neurons of the posterior cardiac plate-pyloric system in the stomatogastric ganglion of a stomatopod, Squilla oratoria, were studied electrophysiologically. Each class of neurons involved in the cyclic bursting activity was able to trigger an endogenous, slow depolarizing potential (termed a driver potential) which sustained bursting. Endogenous oscillatory properties were demonstrated by the phase reset behavior in response to brief stimuli during ongoing rhythm. The driver potential was produced by membrane voltage-dependent activation and terminated by an active repolarization. Striking enhancement of bursting properties of all the cell types was induced by synaptic activation via extrinsic nerves, seen as increases in amplitude or duration of driver potentials, spiking rate during a burst, and bursting rate. The motor pattern produced under the influence of extrinsic modulatory inputs continued for a long time, relative to that in the absence of activation of modulatory inputs. Voltage-dependent conductance mechanisms underlying postinhibitory rebound and driver potential responses were modified by inputs. It is concluded that endogenous cellular properties, as well as synaptic circuitry and extrinsic inputs, contribute to generation of the rhythmic motor pattern, and that a motor system and its component neurons have been highly conserved during evolution between stomatopods and decapods.Abbreviations AB anterior burster neuron - CoG commissural ganglion - CPG central pattern generator - lvn lateral ventricular nerve - OG oesophageal ganglion - pcp posterior cardiac plate - PCP pcp constrictor neuron - PD pyloric dilator neuron - PY pyloric constrictor neuron - son superior oesophageal nerve - STG stomatogastric ganglion - stn stomatogastric nerve  相似文献   
63.
The inhibitory effect of capsaicin on axoplasmic transport in cultured dorsal root ganglion cells was analyzed by video-enhanced contrast microscopy. Capsaicin inhibited particle transports in a dose-dependent manner, irrespective of the diameter of axons. The effect of capsaicin was reversible at low concentrations. Capsaicin affected both the anterograde and retrograde transport. Large organelles were more sensitive to capsaicin than small ones in the retrograde transport. An experiment using calcium-sensitive dye, Fura 2, indicated that capsaicin raised the intraneuronal free calcium concentration preceding the inhibition of the transport. Electron microscopy revealed that microtubules and neurofilaments are disorganized and disoriented by capsaicin. We reached a conclusion that capsaicin inhibits fast axoplasmic transport of both anterograde and retrograde directions in all types of somatosensory neurons in culture by disorganizing intraaxonal cytoskeletal structures, through the elevated intracellular Ca2+ concentration. © 1993 John Wiley & Sons, Inc.  相似文献   
64.
摘要 目的:探讨血清肿瘤标志物与宫颈癌病理特征的关系及对术后复发的预测研究。方法:选择2015年1月至2017年12月来我院诊治的宫颈癌患者82例作为观察组,选择同期来我院体检的健康女性者50例,两组均使用电化学发光免疫分析法检测血清中的CA125、CA153、CA199、CEA水平,观察组患者随访时间截至2022年12月。对比两组血清CA125、CA153、CA199、CEA水平,分析观察组患者血清CA125、CA153、CA199、CEA水平与临床病理特征的关系,分析观察组患者术后随访复发情况,宫颈癌根治术后患者复发的单因素与多因素Cox回归结果,血清CA125、CA153、CA199、CEA水平对宫颈癌根治术后复发的预测价值。结果:观察组的血清CA125、CA153、CA199、CEA水平明显较对照组高(P<0.05)。宫颈癌患者不同FIGO分期、间质浸润深度及是否存在淋巴结转移间血清CA125、CA153、CA199、CEA水平对比有统计学意义(P<0.05)。82例患者随访时间为13~60个月,中位生存时间为39个月,截止2022年12月末次随访,82例患者术后复发18例(21.95%)。单因素及多因素Cox回归分析表明,FIGO分期在ⅡA期、间质浸润深度≥1/2、有淋巴结转移、CA125≥307.41 U/mL、CA153≥185.89 U/mL、CA199≥153.23 U/mL、CEA≥30.15 ng/mL是影响宫颈癌术后复发的独立危险因素。ROC曲线显示,CA125+CA153+CA199+CEA预测宫颈癌术后复发的AUC明显较CA125、CA153、CA199、CEA单独指标预测价值高(P<0.05)。结论:宫颈癌患者血清CA125、CA153、CA199、CEA高表达,其与间质浸润深度、FIGO 分期、淋巴结转移、术后复发有关,四者联合可作为宫颈癌术后复发的预测指标。  相似文献   
65.
We developed a physiologically plausible model of the first steps of spatial visual information processing in the fovea of the human retina. With the predictions of this model we could support the hypothesis that, for moderate contrasts ( 40%), hyperacuity is mediated by the magnocellular (MC-) pathway. Despite the lower sampling density in the MC pathway, as compared to the parvocellular (PC-) pathway, the information that is transferred by the MC ganglion cells is sufficient to achieve thresholds comparable to those of human subjects in psychophysical tasks. This is a result of the much higher signal-to-noise ratio of the MC pathway cell signals. The PC pathway cells do not transfer enough information for hyperacuity thresholds.  相似文献   
66.
A set of 300 vaginal smears was interpreted by 13 cytologists from six European laboratories, who were requested to report inadequate and suboptimal smears. the set had been appropriately seeded to reach approximately 10% inadequate and 20% suboptimal smear frequency. According to the majority report, 230 smears were classified as adequate (76.7%), 43 as inadequate (14.3%), and 27 as suboptimal (9.0%). Agreement with the majority report ranged from 52% to 91% (average 78%). Kappa statistics for reporting inadequate smears showed a high level of agreement for five cytologists, and fair to good agreement for eight. In contrast, K statistics for reporting suboptimal smears showed fair to good agreement with the majority report only in five instances, whereas agreement was poor for eight cytologists. ‘Inadequate smear’rates may be used to compare the quality of smears received in different laboratories, as there is a high level of agreement among cytologists as to what constitutes an inadequate smear. However, this is not true for ‘suboptimal smear’ rates, and more precise reporting criteria must be defined and tested if an intermediate category is to be retained to report poor quality smears: more precise reporting criteria must be defined and tested if an intermediate category is to be retained to report poor quality smears. Une série de 300 frottis cervico-vaginaux a été examinee par 13 cytologistes appartenant à 6 laboratoires européens auxquels il avait été demandé de signaler les frottis inadéquats et sub-optimaux. Cette série de frottis a été constituée de façon à atteindre approximativement une fréquence de 10% de frottis inadéquats et de 20% de frottis sub-optimaux. Si I'on considère les réponses faites par la majorité des cytologistes, 230 frottis ont été classés adéquats (76,7%), 43 classés inadéquats (14,3%), et 27 comme sub-optimaux (9,0%). La concordance avec les réponses de la majorité des cytologistes varie de 52%à 91% (moyenne 78%). Concernant le signalement des frottis inadéquats, le test Kappa est excellent pour 5 cytologistes et moyen à bon pour les 8 autres. Au contraire, pour le signalement des frottis sub-optimaux, le test Kappa montre un accord moyen à bon avec les réponses de la majorité seulement dans 5 cas alors que I'agrément est mauvais pour 8 cytologistes. La fréquence des frottis inadéquats peut être utilisée pour comparer la qualité de prélèvement du frottis dans différents laboratoires, alors que les comparaisons de la fréquence des frottis sub-optimaux sont discutables, du fait d'un biais de diagnostic évident. Des critéres plus précis pour le signalement des frottis sub-optimaux doivent étre définis et testés si cette catégorie doit être retenue pour rapporter les frottis de mauvaise qualité. 300 Abstriche wurden durch 13 Zytologen aus 6 europäischen Laboratorien hinsichtlich der Kriterien ‘unbrauchbar’und ‘suboptimal’beurteilt. Die Sammlung enthielt etwa 10% unbrauchbare und 20% suboptimale Präparate. Mehrheitlich wurden 230 Abstriche als auswertbar (76,7%), 43 als unbrauchbar (14,3%) und 27 als suboptimal (9,0%) bezeichnet. Die Statistik ergab hinsichtlich der unbrauchbaren Abstriche eine ausgezeichnete Ûbereinstimmung für 5 und eine gute Ûbereinstim-mung für 8 Zytologen. Demgegenüber zeigte sich hinsichtlich der Beurteilung suboptimal nur 5mal eine gute und 8mal eine schlechte Ûbereinstimmung. Damit ist die Kategorie suboptimal ungeeignet zum Vergleich und bedarf einer genaueren Definition wenn sie für die Qualitätskontrolle eingesetzt werden soll.  相似文献   
67.
在培养1─2周的大鼠颈上神经节交感神经元标本上,用膜片钳技术记录了单烟碱受体通道电流及胆碱能突触电流,并分析了它们之间的关系。单烟碱受体通道至少有三种亚导状态,即15pS,27pS,38pS,其中以27pS最常见。通道有两种开放模式,即单个短促开放与长串开放。对应的平均开放时间分别为τ_1=1.71ms,τ_2=12.24ms。对自发突触电流的分析表明,其下降相的衰减时间常数(τ=15.7±1ms)与上述长串开放的持续时间相当,提示在突触传递过程中,突触前末梢释放的ACh引起了突触后神经元烟碱受体通道的长串开放。  相似文献   
68.
电刺激蝙蝠小脑对中脑上丘神经元听反应的影响   总被引:2,自引:0,他引:2  
实验在23只成年中华鼠耳蝠(Myolischinensis)上进行。使用常规电生理学方法,观察了电刺激小脑对上丘神经元听反应的影响。在所观察的171个上丘神经元中,有116个(占67.84%)神经元听反应受到影响,其中72个(占42.11%)表现为抑制效应,44个(占25.73%)为易化效应。刺激小脑对上丘神经听反应的影响是双侧的。抑制或易化程度与电刺激强度、声刺激强度以及声、电刺激间隔有关。结果提示,小脑可以对上丘神经元听反应进行调制,这种调制作用可能是小脑调控回声定位过程中听觉-运动的中枢机制之一。  相似文献   
69.
Abstract: We have previously demonstrated that the in vivo vitreal injection of an antisense oligonucleotide directed to the kinesin heavy chain inhibits retinal kinesin synthesis by 82% and concomitantly inhibits rapid transport of total protein into the optic nerve by 70%. These results establish a major role for kinesin in rapid axonal transport in vivo. Recently, the cloning of a family of kinesin-like molecules from the mammalian brain has been reported, and some of these proteins are also expressed in neurons. To assign a specific function to the kinesin heavy chain we inhibited the kinesin synthesis with an antisense kinesin oligonucleotide and assessed the axonal transport into the optic nerve of representative proteins from each of three vesicle classes that contain rapidly transported proteins. Marker proteins used were substance P for peptide-containing synaptic vesicles, the amyloid precursor protein for plasma membrane precursor vesicles, and several integral synaptic vesicle proteins. Our results indicate that the major anterograde motor protein for all three vesicle classes utilizes kinesin heavy chain, although we discuss alternative explanations.  相似文献   
70.
Abstract: This study attempts to determine if the medial (MSO) and lateral superior olive (LSO), medial nucleus of the trapezoid body (MNTB), ventral nucleus of the lateral lemniscus (VNLL), and central nucleus of the inferior colliculus (ICc) contain glutamatergic synaptic endings. Micropunch and microdissection procedures provided fresh samples of these auditory nuclei for the measurement of the high-affinity uptake and electrically evoked release of exogenous d -[3H]ASP. The study also determined if the LSO and MSO contain glycinergic synaptic endings by measuring uptake and release of [14C]-Gly in these nuclei, and whether the MNTB, VNLL, and ICc contain GABAergic endings by assessing the uptake and release of [14C]GABA in these structures. Several strategies optimized the evoked Ca2+-dependent release of the labeled amino acids. These included the enhancement of high-affinity uptake during loading of the markers into the tissues, inhibition of uptake during the subsequent measurement of release, and use of an electrical stimulus current that evoked maximal Ca2+-dependent release. Each of these nuclei manifested the high-affinity uptake and the evoked Ca2+-dependent release of d -[3H]Asp, suggesting the presence of synaptic endings that may use Glu or Asp as a transmitter. Similar findings suggest the presence of glycinergic synaptic endings in the LSO and MSO, and of GABAergic synaptic endings in the MNTB, VNLL, and ICc.  相似文献   
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