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At least 19 recordsLinked to original sources
PubMed1977

[Collateral circulations and new vessels in retinal branch vein occlusions. II. New vessels (author's transl)].

Two types of anastomotic new vessels develop after retinal branch vein occlusions. In a previous article (Arch. Ophtal. (Paris), 1977, 8-9, pp. 507-522) the useful collateral vessels were described in the re-establishment of a better circulation in the territory of the occluded vein. The second part discusses new vessels: they are dangerous and useless. Their pathogenesis poses the problem of the relationship between hypoxia, ischaemia, revascularisation and vasoproliferation. Their prevention and treatment calls for laser photocoagulation of the ischaemic territory.

Argon↗
PubMed1977

Lymphatic vessels of the human dental pulp.

Noncarious teeth obtained from individuals 15 to 50 years of age were used to study the lymphatic drainage of the human pulp. Thick sections (50 to 150 microns) were stained with iron hematoxylin for the demonstration of lymph and blood vessels. Lymph capillaries originated as blind sacs in the odontoblastic layer and in the pulp proper near the pulpo-odontoblastic border. They drained into small thin-walled collecting vessels that were irregular in shape and showed great variability in their drainage patterns. Communications between these vessels were very common. The larger conducting lymphatic vessels accompanied the blood vessels and nerves in their course through the pulp. They could be identified by their thin walls and small size. The large caliber lymphatic vessels contained valves, a structure not present in the veins of the same size. The conducting lymphatic vessels passed through the roots as individual units without draining into a large single vessel. The lymphatic vessels of the human pulp must be considered as a pathway for the removal of excessive tissue fluid in normal and diseased pulps.

Adolescent↗
PubMed1975

[The effect of the argon laser on the vessels, the macro- and microcirculation of the mucosa of the hamster cheek-pouch. An intravitalmicroscopic study (author's transl)].

The mucosa of the cheek-pouch of five golden Syrian Hamsters was irradiated with the beam of an argonionlaser (diameter 0.5 mm and 200 mW). The effect on the micro- and macro-vessels and the bloodstream, especially of the microcirculation, is studied intravitalmicroscopically. In the microcirculation and also in the small and large venous and arterial vessels a restriction of bloodstream, praestasis, pendulumstream, stream reversal and some white microthrombi, -- emboli and agglutination of erythrocytes are visible. The bloodless welding of the vessels takes place even before the evaporation and coagulation necrosis of the surrounding epithelium of the mucosa as a result of the relatively selective effect of the Argon Laser on the reddish vessel-system by a continuous narrowing of the vessels-walls to the complete loss of their lumen rather than by a thrombosis. Firstly the capillaries, the venoles and the arterioles are obliterated, then those of middle size and at last the large venae and arteries in which case large vessels function for a moment as smaller ones. A continuously growing imbibition with increasing duration of the laser irradiation can be observed. Three clinically important phenomenon, depending on the laserdose can be observed: 1. a partial, 2. a subtotal and total obliteration of the network of the vessels, and 3. a total destruction of the blood-vessels and also of the tissue. Therefore clinically a subtotal or total network obliteration of the blood-vessels of strongly vascularised tissues, haemangiomas, teleangiectasias in case of morbus Rendu-Weber-Osler and livid enlarged nasal conchae might be obtained. Further a total tissue-destruction with a break in the continuity of the tissue for example with strongly vascularised carcinoma or its metastases might be effected.

Animals↗
PubMed1978

Fluid leaks from extra-alveolar vessels in living dog lungs.

Edema transudation from extra-alveolar vessels was investigated in anesthetized, open-chested dogs. Fluid accumulation at different alveolar and extra-alveolar vascular pressures was assessed by continuous lung weighing and microscopy. The left (experimental) lung was distended with 6% CO2 and air while normal arterial blood gases were maintained by separately ventilating the right lung. Extra-alveolar vessels were isolated by compressing alveolar vessels with alveolar pressures high enough to stop blood flow. Weight increased steadily (edemogenesis) when pulmonary arterial and/or pulmonary venous pressure was 1 cmH2O below this pressure. Because some alveolar vessels at the lung base could have remained open and leaked, extra-alveolar vessels were also separated from alveolar vessels by glass bead embolization sufficient to stop perfusion. Lung weight gains followed selective pulmonary arterial or venous pressure elevations. Electron microscopy demonstrated edema in experimental lobes which was not present in control lobes with undistended extra-alveolar vessels at the same alveolar pressure. Thus pulmonary edema can be caused by fluid leaking from extra-alveolar vessels.

Animals↗
PubMed1977

Electron-microscopic analysis of iris vessels in two cases of uveitis.

Electron-microscopic analysis of iris biopsy material was carried out paying particular attention to vessels and infiltrating cells. Characteristic changes of vessels and cells were found in two cases. One showed abundant lymphodiapedesis, perivascular infiltration, and vessels appearing morphologically normal. The other showed diffuse infiltration of cells and numerous fenestrated newly formed vessels. In the latter, three different types of opening in the endothelium were observed: (1) separation of intercellular junctions; (2) small pores or defects in the endothelium, and (3) large holes or defects in the endothelium. Cell leakage from normal and newly formed vessels was considered. We concluded that lymphocytes may migrate through the cytoplasm within membrane-bounded vesicles in normal vessels, whereas in newly formed fenestrated vessels cells, including small lymphocytes, may pass through three different types of opening in the endothelium.

Aged↗
PubMed1977

Cryocoagulation of retinal vessels: an experimental model of intravascular coagulation.

Various amounts of cryothermy were applied to the posterior pole of rabbit eyes to determine changes in retinal tissue and vasculature. Four consecutive freezing and refreezing applications of -60 degrees was the most effective technique for achieving central retinal vessel occlusion. Electron microscopic observations of sequentially sectioned occlusion. Electron microscopic observations of sequentially sectioned occluded vessels showed that the vessels were occluded by a platelet plug distally and packed erythrocytes proximally. Fibrin formation was not found in the occluded retinal vessels but was seen within platelet plugs in choroidal vessels. Because cryocoagulation simulates the normal physiologic means of coagulation more closely than other vessel occluding techniques, cryocoagulation of the primary retinal vessels is suggested as an experimental model for intravascular coagulation.

Animals↗
PubMed1975

Anterior and posterior groups of portal vessels in the avian pituitary: incidence in forty nine species.

The hypophyseal portal vessels were studied in forty nine species of birds. The primary capillary plexus in the median eminence is single or divided into an anterior and a posterior plexus. Irrespective of whether the primary capillary plexus is single or divided, distinct, non-interconnected anterior and posterior groups of portal vessels are present in all the species investigated. The anterior group of portal vessels originates in the anterior region of the median eminence and breaks up into capillaries in the cephalic lobe of the pars distalis; the posterior group of portal vessels originates in the posterior region of the median eminence and breaks up into capillaries in the caudal lobe of the pars distalis. This type of regional distribution of portal vessels appears to be of general occurrence in the avian pituitary. The median eminence in the species investigated shows an AF-positive anterior region and an AF-negative posterior region. The pars distalis is differentiated into histologically distinct cephalic and caudal lobes. The arrangement of the portal vessels into anterior and posterior groups provides morphological basis for the view that the functions of the cephalic lobe may be controlled by the anterior median eminence, whereas those of the caudal lobe may be controlled by the posterior median eminence. However, experimental data available to date do not suggest a physiological significance to the widespread incidence of the regional distribution of portal vessels in the avian pituitary.

Animals↗
PubMed1977

The architecture of the most peripheral retinal vessels.

The vascular bed of the extreme periphery of the human retina is characterized by the occurrence of relatively wide arcades and bridging vessels connecting the peripheral portions of arteries and veins. These vessels differ from the more posterior capillaries not only by their larger diameter but also by the presence of a perivascular halo, which consists of an electron-translucent ground substance containing fine collagen fibrils, basement membrane material, dense bodies, vesicles, and portions of macrophages. The appearance of the external portion of the halo and the relationship of its collagen fibrils to the basement membrane of the surrounding Müller cells is indistinguishable from that of the cortical vitreous and the inner limiting membrane located at the vitreoretinal interface. Toward the periphery the thickness of the halo increases from vessel to vessel. As a rule, one or more of the vessel loops closet to the ora serrata are occluded. The structure of these occluded vessels is identical with the structure of the halo.

Animals↗
PubMed1978

Thrombogenic effect of high-dose aspirin in rabbits. Relationship to inhibition of vessel wall synthesis of prostaglandin I2-like activity.

Aspirin is a promising antithrombogenic agent. It inhibits the generation of thromboxane A(2) by acetylating platelet cyclo-oxygenase. Aspirin also inhibits vessel wall production of PGI(2) which is an inhibitor of platelet aggregation, and therefore is potentially thrombotic. To investigate these two opposing effects we studied the effects of aspirin upon fibrin accretion onto experimentally induced venous thrombi in rabbits and on the PGI(2)-like activity of vessel wall using the thrombin-induced [(14)C]serotonin release assay. A 200-mg/kg dose of aspirin significantly augmented thrombus size when compared to (a) sodium salicylate administered in equal doses, (b) aspirin in a 10-mg/kg dose or (c) controls (P < 0.001). A 200-mg/kg dose of aspirin totally inhibited vessel wall PGI(2)-like activity whereas aspirin in a 10-mg/kg dose produced less inhibition, and 200 mg/kg sodium salicylate had no effect. Local instillation of tranylcypromine, an inhibitor of PGI(2) formation, also significantly augmented thrombus size compared to saline-treated controls and totally inhibited the production of PGI(2)-like activity. The thrombogenic effect of high dose aspirin was lost if an interval of 2.5 h or longer elapsed between vessel damage and drug administration, indicating that in contrast to the platelet, the effect of aspirin on vessel wall prostaglandin synthesis is relatively short-lived. It is concluded that aspirin, in doses higher than those used clinically, can augment experimental thrombosis, presumably by inhibiting the synthesis of vessel wall PGI(2).

Animals↗
PubMed1975

[The scope and limitations in the demonstration of vessels by angiotomography; their relationship with contrast and size and between detail and direction of cut (author's transl)].

Experiments with models and post mortem angiograms have shown that the supposed advantages of angiotomography, such as determination of the depth of vessels, cannot be achieved with accuracy if there is repeated change in direction of the vessels. Blurring of superimposed vessels depends not only on their contrast and calibre, but also on their alignment in relationship to the direction of blurring. Vessels running in the direction of blurring produce undesirable shadows through a considerable depth, whereas vessels running across the direction of blurring are rapidly blurred if not in the selected plane. The demonstration of vessels running at right angles to the direction of blurring may at times be very difficult with simultaneous tomography. The clinical significance of this finding is pointed out.

Angiography↗
PubMed1979

Vascular substances that modulate blood-to-vessel interactions.

The vessel wall contains powerful inhibitors of thrombogenesis. One substance, a proteoglycan, is a strong anticoagulant but has only a limited effect on platelet aggregation. It prolongs the thrombin clotting time and partial thromboplastin time, but only blocks platelet aggregation induced by thrombin. Another vessel wall constituent, a prostaglandin derivative (prostacyclin), is a potent inhibitor of platelet aggregation. It antagonizes platelet aggregation induced by a variety of agents including adenosine diphosphate, collagen, arachidonic acid and thrombin; however, its only effect on coagulation is through the inhibition of platelet factor-3 release. Proteoglycans and prostacyclin comlement each other's antithrombotic activities, and together serve to limit the hemostatic response of blood to vessel wall injury. Vessels devoid of the intima continue to produce prostacyclin. Prostacyclin produced by these vessels is probably more important than that produced by vessels with the intima in the prevention of thrombus deposition.

Animals↗
PubMed1978

Drug effects on platelet adherence to collagen and damaged vessel walls.

The interaction of platelets with damaged vessel walls leads to the formation of platelet-fibrin thrombi and may also contribute to the development of atherosclerotic lesions because platelets adherent to exposed collagen release a mitogen that stimulates smooth muscle cell proliferation. The first step in thrombus formation, platelet adherence to an injured vessel wall, can be studied quantitatively by the use of platelets labeled with 51chromium. In these investigations, rabbit aortas were damaged by passage of a balloon catheter and segments of the aortas were everted on probes that were rotated in platelet suspensions. Collagen-coated glass cylinders were also used. Adherence was measured in a medium containing approximately physiologic concentrations of calcium, magnesium, protein and red blood cells. Conditions of testing influence the effect of non-steroidal anti-inflammatory drugs, sulfinpyrazone, and dipyridamole on platelet adherence. Aspirin and sulfinpyrazone were not inhibitory when tested in a medium with a 40% hematocrit; this indicates that products formed by platelets from arachidonate probably do not play a major part in the adherence of the first layer of platelets to the surface, although they may be involved in thrombus formation. Indomethacin, dipyridamole, prostaglandin E1, methylprednisolone and penicillin G and related antibiotics did inhibit platelet adherence although the concentrations required were higher than would likely be achieved in vivo upon administration to human patients. None of the non-steroidal anti-inflammatory drugs inhibited the release of granule contents from adherent platelets. Pretreatment of the damaged vessel wall with aspirin increased platelet adherence, presumably because it prevented the formation of PGI2 by the vessel wall. Platelet adherence to undamaged or damaged vessel walls was enhanced by prior exposure of the wall to thrombin. Platelet reactions with aggregating agents and platelet survival can be modified by changes in dietary lipids but there is very little evidence concerning the effects of lipids on platelet adherence. If some forms of dietary fat damage the endothelium, platelet interaction with the damaged area and release of the mitogen for smooth muscle cells would contribute to the development of atherosclerotic lesions.

Animals↗
PubMed1979

Automated image analysis for measurements of morphological reactions of blood vessels of the microvascular system.

Using a modification of the Mg-ATPase reaction, the arterial blood vessels of the microcirculatory bed of the rat including the smallest precapillary vessels are visualized in a grey-level difference against their environment which permits to utilize the automatic image analyser QUANTIMET 720 and the programmable desk-top calculator HEWLETT-PACKARD 9100B. The article describes the method for preparing the sections, the measuring procedure, and the statistical verification of the results by means of the computer assisted two-way analysis of variance as well as studies demonstrating the reliability of the method. It is concluded that the procedure at heart, skeletal muscle and pancreas specimens of the rat demonstrates reliably and effectively changes of the number of vessels and the projected whole vessel wall area as well as differences of enzyme activities. Thus it is possible to detect structural wall reactions and enzyme histochemical changes of arterial blood vessels of the microvasculatory bed including its smallest precapillaries which have been practically inaccessible to histomorphometrical investigations in the past.

Adenosine Triphosphatases↗
PubMed1978

Ultrastructure of human dermal blood vessels with special reference to the endothelial filaments.

The ultrastructure of endothelial cytoplasmic filaments of small blood vessels from the human dermis has been described. The material consisted of biopsies from normal abdominal and thoracic skin and also from the skin of patients with urticaria pigmentosa. Most vessels were surrounded by multiple layers of basal lamina and corresponded to the small venules of the subpapillary dermis. The wall of many vessels was composed by endothelial cells with clear cytoplasm which was rich in filaments and by endothelial cells with a dense cytoplasm which was poor in filaments. Some vessels had walls composed of clear endothelial cells only. The filaments varied in diameter between 80-120 A. Curling, recoiling and whorling of cytoplasmic filaments were obvious in endothelial cells of contracted vessels. Bulging of endothelial nuclei and nuclear indentations were seen in the skin lesion of urticaria pigmentosa. The possibility that the clear endothelial cells which are rich in filaments may be more actively involved in contraction than the dense cells, is discussed.

Adult↗
PubMed1979

Superiority of the deep circumflex iliac vessels as the supply for free groin flaps. Clinical work.

In this paper we present 16 cases of free transfer of compound flaps from the groin, 11 using the deep circumflex iliac vessels as a stem and 5 using the superficial circumflex iliac vessels as a stem. We found the deep vessels superior in many ways to the superficial vessels for this purpose; they are larger, permitting greater ease in anastomoses and providing more reliable blood flow. We believe that larger osteocutaneous or myocutaneous flaps can be transferred on the deep vessels than on the superficial ones-and that the deep circumflex iliac flap may supplant the conventional free going flap in most situations. The method evolved in response to patient need, not for surgical éclat.

Adolescent↗
PubMed1979

Hypertensive breakdown of cerebral but not of retinal blood vessels in rhesus monkey.

Acute hypertension, induced either by intravenous injection of metaraminol bitartrate (Aramine), infusion of isotonic saline into the common carotid artery, or a combination of both procedures did not in the rhesus monkey lead to breakdown of the blood-retinal barrier. Whereas the cerebral vasculature was made permeable to blood-borne dye at carotid pressure above 160 mm Hg, the retinal blood vessels were intact even at pressures as high as 310 mm Hg. Hypertensive blood-brain barrier opening was associated with neurologic defects and brain edema. The results indicate that the retina is more resistant to acute hypertension than is the brain. The greater resistance in the retina may be due to the high number of contractile, perivascular mural cells counteracting increased intravascular hydrostatic pressure. An alternative or supplementary explanation is that choroidal and retinal blood vessels are better protected from surges in blood pressure than are brain blood vessels. Differences between the innervation of brain and ocular blood vessels could account for this.

Animals↗
PubMed1979

A histochemical study on the innervation of cerebral blood vessels in the bullfrog.

Specific histochemical techniques for the demonstration of catecholamine and acetylcholinesterase have been used to study the distribution of adrenergic and cholinergic nerves on the cerebral blood vessels of bullfrog, Rana catesbeiana. The adrenergic nerve meshworks on the cerebral arteries of bullfrog were less dense, had a more elongate appearance along the arterial axis as compared with those of mammals and were rather similar to those of snakes. The nerve plexuses on the cerebral carotid artery and its main branches were somewhat denser than those on the basilar artery. The most characteristic feature of innervation in the bullfrog cerebral vessels was that no acetylcholinesterase-positive fibres were observed on the extraparenchymal arteries, whereas, in all higher vertebrates investigated so far, the cerebral arteries have been found to be dually innervated although differences in the density of innervation of the two nerves may exist. This suggests that the peripheral adrenergic innervation on the cerebral blood vessels appeared earlier than the cholinergic one in the evolution of vertebrates. On the other hand, both adrenergic and acetylcholinesterase-positive fibres were observed in close contact with parenchymal arterioles and capillaries suggesting the possible existence of a dual central innervation. This feature, however, was by no means common. Thus, the central neurons have a significant influence on the cerebral circulation in the bullfrog is somewhat equivocal. Most of the pial and the parenchymal small vessels and the parenchymal capillaries exhibited a heavy acetylcholinesterase activity on the vascular walls. Although the significance of the enzyme is obscure as yet, this has to be considered in relation to the regulatory mechanism of the cerebral circulation.

Adrenergic Fibers↗
PubMed1979

The visible vessel as an indicator of uncontrolled or recurrent gastrointestinal hemorrhage.

Although endoscopic examination in patients with bleeding of the upper gastrointestinal tract has improved diagnostic accuracy, it has not been useful in predicting clinical outcome and has not been shown to improve the patients' prognoses. This article describes a subgroup of patients with acute upper gastrointestinal bleeding whose clinical outcome can be predicted at the time of endoscopy. In 28 of 317 patients who underwent endoscopy, a "visible vessel" was seen in an ulcer presumed to be the bleeding site. All 28 were later recommended for operation because of recurrent (86 per cent) or uncontrolled (14 per cent) hemorrhage. In contrast, 75 per cent of the remaining 289 patients in whom vessels were not seen, whether or not bleeding from ulcers, had single bleeding episodes managed medically. Since patients with a "visible vessel" can be expected to have uncontrolled or recurrent hemorrhage, surgical treatment should be considered at the time of endoscopy if such a vessel is seen.

Acute Disease↗