颈内动脉岩内段形态位置与毗邻结构的相关分析

目的:探讨颈内动脉岩内段形态位置变化的规律及其与毗邻结构的关系.方法:对66侧正常成人颅底高分辨率CT连续图像进行分析,测量颞骨气房体积,建立定位颈内动脉岩内段及其毗邻结构的参照系,对其位置和形态进行测量,运用偏相关分析方法求出它们形态位置的变化规律及其影响因素.结果:在男性,颈内动脉垂直段更偏外侧,其水平段长度也大于女性.颞骨气化好,则颈内动脉垂直段更偏后移.颈内动脉垂直段与颈静脉球的位置变化表现为同步.垂直段的内外移位相应地使水平段与中线的夹角发生变化.颈内动脉水平段的方位与蜗轴方向相关,蜗轴偏离中线的角度越小,则颈内动脉水平段偏离中线的角度越大,反之亦然.结论:影响颈内动脉岩内段形态位置变化的因素是复杂和多重的,包括性别因素、颅底发育状态、颞骨气化程度以及毗邻结构发育状态均可能是影响因素.     

Inhibition in carotid body chemoreceptors mediated by D-2 dopaminoceptors: Antagonism by benzamides

Inhibition of chemosensory nerve impulses in the cat is evoked by dopamine (DA) applied to carotid body chemoreceptors. Pharmacological characterization of the dopaminoceptors involved in this action was determined through their blockade with benzamides, selective antagonists of D-2 receptors. Both metoclopramide and sulpiride were effective blockers of DA-induced chemosensory inhibition. Furthermore, both drugs induced an immediate increase in the frequency of carotid nerve chemosensory impulses, suggesting the presence of previous tonic inhibition of chemoreceptor discharges by endogenous DA released from glomus cells.     

Evidence for central reorganization of ventilatory chemoreflex pathways in the cat during regeneration of visceral afferents in the carotid sinus nerve

There are two sets of peripheral arterial chemoreceptors in the cat, the carotid bodies innervated by the carotid sinus nerve and the aortic bodies with afferents in the aortic depressor nerves. Reflex stimulation of ventilation in response to hypoxia is abolished acutely after interrupting the sensory pathway from the carotid body chemoreceptors in the cat even though the reflex pathway from the aortic body chemoreceptors is intact. However, in chronically maintained preparations, there is a restoration of the hypoxic response which is mediated by the aortic chemoreflex pathway. It was proposed that restoration was due to a ‘central reorganization’ of chemoreflex pathways which followed interruption of the sensory pathway from the carotid bodies and that the reorganization enhanced the efficacy of the aortic ventilation chemoreflex. This proposal was tested in the present experiments by measuring reflex ventilatory and cardiovascular responses to electrical stimulation of the sensory nerves containing aortic and carotid chemoreceptor afferents following bilateral interruption of carotid sinus nerves and carotid body resection. Responses measured acutely (1–6 h) after interruption were compared with those measured 60–80 and 110–140 days later. At 60–80 days, a chemoreflex response (increase in tidal volume of ventilation) to stimulation of the interrupted carotid sinus sensory pathway was markedly attenuated while the response to stimulation of the uninterrupted pathway in aortic depressor nerves was enhanced. At 110–140 days, the tidal volume response to carotid sinus nerve stimulation was greatly enhanced while the aortic depressor nerve response declined from the elevated level. There were significant but less pronounced changes in the response of other ventilatory and cardiovascular variables to aortic depressor nerve and carotid sinus nerve stimulation.The results support the idea that there is a ‘central reorganization’ of chemoreflex pathways which is reflected functionally by changes in the efficacy of reflexes evoked from aortic depressor nerve and carotid sinus nerve. The changes are analagous to those occurring in somatic reflexes during regeneration of sensory nerves. It is suggested that the changes in efficacy of carotid sinus nerve reflexes are due to a degenerative loss of synapses of the central projections of interrupted carotid sinus nerve sensory axons (degenerative atrophy) and subsequent regenerative like changes (regenerative proliferation) in the central projections. The changes in the efficacy of aortic depressor nerve reflexes may be attributed to formation of new synapses by converging central projections of this uninterrupted pathway (reactive synaptogenesis) and subsequent regression of the newly formed synapses.     

The thrombin inhibitor argatroban does not influence the endothelium-dependent relaxant and contractile responses of isolated rabbit carotid arteries

Atherosclerotic endothelial dysfunctions are associated with a reduced NO production, which is probably due to impaired NO synthase (eNOS) activity or a deficiency of the substrate L-arginine. In the present studies, the influence of argatroban on isolated rabbit carotid arteries was investigated to determine whether the arginine derivative argatroban can improve the endothelium-dependent relaxation.

Rings from rabbit carotid arteries were placed in 10 ml organ baths for isometric tension recording. Endothelial integrity was assessed by the acetylcholine-induced relaxation of PGF₂-precontracted rings; after mechanical removal of the endothelium the relaxation was abolished. Preincubation of the vessels in vitro with L-NAME, an inhibitor of the eNOS, diminished significantly the acetylcholine-induced relaxation by more than 50%. After i.v. application of L-NAME (100 mg/kg) in rabbits, relaxation in response to acetylcholine was significantly reduced compared to the control when the vessels were studied ex vivo in an organ bath. The contractile effects of phenylephrine and 5-HT were slightly enhanced.

Argatroban is a selective, potent, synthetic thrombin inhibitor; after i.v. application at doses of 0.5 and 1.0 mg/kg, a significant prolongation of the plasma coagulation time (measured as thrombin time and a PTT) of up to 60 min was found in rabbits.

In vitro argatroban did not affect the acetylcholine-induced relaxation or the contractile response to phenylephrine and 5-HT. After i.v. application, the ex vivo experiments in the organ bath showed that after 30 min the relaxant responses of the carotid arteries to acetylcholine and the contractile effects of phenylephrine and 5-HT were not influenced by pretreatment with argatroban. The present studies suggest that argatroban has no vascular effects in vitro and ex vivo in normal rabbits.     

Immunohistochemical localization of apolipoproteins A-I and B in human carotid arteries

Decreased plasma levels of apolipoprotein A-I (apo A-I) and increased plasma levels of apolipoprotein B (apo B) have been shown to correlate with increased risk of atherosclerosis. While many studies have investigated the plasma levels of these apolipoproteins with regard to their value as predictors of cardiovascular disease, comparatively little is known about their precise tissue localization in atherosclerotic plaques. The purpose of this study was to determine the tissue localization of apo A-I and apo B in atherosclerotic segments of human carotid arteries through the use of immunohistochemical techniques. With tissue samples obtained from surgery and autopsy, apo A-I and apo B were found to be present in atherosclerotic plaques and absent in normal arterial tissue. In the plaques, both apo A-I and apo B were found extracellularly, primarily in the lipid core, but also in connective tissue. In addition, both apo A-I and apo B were found intracellularly in foam cells. This similar intracellular and extracellular distribution of apo A-I and apo B was unexpected, in view of their differing associations with atherosclerosis.     

Epoxy-resin injection of the cerebral arterial microvasculature: An evaluation of the limits of spatial resolution in 8 Tesla MRI

The purpose of this study was to quantify the spatial resolution of microscopic arteries on magnetic resonance images acquired at 8 Tesla (T). Techniques similar to those used for standard MRI of the human brain in vivo at 8 T were utilized to generate high-resolution gradient echo (GE) images of a whole postmortem human brain whose common carotid arterial system had been injected with an epoxy-resin. Single slice images, along with summed images of up to 5 contiguous slices, were then compared to color digital photographs detailing the distribution of the arterial system on the surface of the same injected brain. There was excellent MR visualization of the microscopic cerebral arteries down to a spatial resolution of 200 microm. Through the use of an 8 T whole-body MRI scanner and standard GE imaging sequences, microscopic arterial structures can be clearly resolved down to a dimension of 200 microm.     

动眼神经池段与周围血管的关系

目的：研究动眼神经池段与周围血管的关系。方法：选取成人头颅标本，红色乳胶灌注，福尔马林固定，在手术显微镜下解剖观测。结果：动眼神经池段腹面的接触血管主要为小脑上动脉(100％)和脑桥后外动脉(42．9％)；背面主要为大脑后动脉(100％)、后交通动脉(14．8％)、四叠体动脉(100％)、副四叠体动脉(10．7％)和脉络膜后动脉(10．7％)。动眼神经滋养动脉主要来自脑底动脉环的后内侧动脉组。穿入动眼神经根的血管主要为四叠体动脉和副四叠体动脉(14．3％)。结论：动眼神经池段与周围血管的关系复杂，该区周围血管的压迫及周围血管的血管瘤可以造成临床眼肌麻痹和相应的中枢神经症状。     

脑动脉DSA形态分析及其意义

目的：探讨脑血管造影各主要动脉的投影规律及其分支的显示率，为脑血管疾病的影像诊断和介入治疗提供重要参考。方法：随机抽取140例全脑血管DSA系列图像，选择其中无脑血管疾病的51例进行观察。分别统计颈内动脉和椎动脉造影时正常脑血管各主要分支的显示率；归纳大脑前动脉A1段、大脑中动脉M1段及大脑后动脉P1段在平面上的投影规律并分析总结了脑动脉的正常解剖学特征及其变异。结果：①脑底动脉变异较大；②颈内动脉照影时OA、AChA、ACoA、PCoA、ACA和MCA的显示率分别为96.1％、92．2％、52．9％、69．6％、100％和100％；③椎动脉造影时PICA、AICA、BA、SCA、PCA和PCoA的显示率分别为66．7％、62．7％、100％、70．6％、80．4％和41．2％。结论：①尽管脑底血管实际解剖关系较为复杂，但造影时反映到平面上可简捷的用“水平、上升、下降”等来描述血管的形态和走行；②虽然是平面图像，通过调整投照体位仍可非常逼真的反映血流的动态变化。     

Intramural sarcoma of the carotid artery with adventitial inflammation and fibrosis resembling 'inflammatory aneurysm'

A rare case Is descrlbed of an Intramural sarcoma of the rlght common carotld artery coexistlng wlth adventitial inflammation and flbrosls, resembllng 'inflammatory aneurysm', which was resected from a 33-yearold Japanese woman who had presented with a pulsatile mass on the rlght side of the anterior neck. Grossly, the wall of the carotld artery showed an intimal tear with dlssectlon of the medla filled with thrombus. A graylsh area, abutting directly onto the dlssected space and Involving the media and inner adventltia, was composed of a-smooth muscle actin-positive and desmln-negative polygonal and splndle cells with large bluntended nuclei and coarse granular chromatin arranged Into a well-organized Interlacing bundle pattern. This portlon was thus considered to represent lelomyosarcoma. White to yellow-tan fibrotic tissue present in the adventitial area consisted of extensive lamellar fibrosis wlth scattered focl of lymphoplasmacytlc aggregates and obliterated arteries, and lacked atypical spindle and polygonal cells. These changes accorded with the histopathologlcal findlngs hitherto described in cases of 'inflammatory aneurysm', which is known to almost exclusively involve the abdominal aorta. We conslder this case unique In that the leiomyosarcoma involved an artery other than the aorta, wlth an 'inflammatory aneurysm'-like reaction in the same she. The posslble relatlonship between these two condltions Is dlscussed.