摘要:

The media of arteries is virtually avascular. Thus, oxygen and nutrients must reach the cells of the media by diffusion from the lumen of the vessel and from adventitial vessels. The thickness of the thoracic aorta of man and dog exceeds the effective diffusion distance of oxygen, but nutrition is supplemented by vasa vasorum which enter into the outer layers of the media. Occlusion of vasa vasorum in dogs produces medial necrosis, which indicates that these vessels are essential for the nourishment of the aorta. Recently the microsphere method has been used to provide the first measurements of blood flow through vasa vasorum. There is substantial flow to the outer layers of media of the thoracic aorta in dogs, with virtually no blood flow in the inner layers. The vessels are very responsive to physiological stimuli: they dilate during infusion of adenosine and constrict during stimulation of sympathetic nerves. During acute increases in arterial pressure, blood flow to the media decreases probably from distortion of vasa vasorum. Vasa vasorum may play a role in disease states. Insufficient blood flow through vasa vasorum may contribute to medial necrosis of the aorta and to aortic atherosclerosis. A role of vasa vasorum in aortic changes in hypertension and other vascular diseases merits further study.

ISSN:1018-1172    

DOI:10.1159/000158209

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

In a group of volunteers, smoking two cigarettes produced a significant increase in the number of circulating endothelial cells. This effect was suppressed in another group by a preventive oral administration of a hydroxyethylrutoside preparation. The results fully confirmed our earlier experimental findings in rats.

ISSN:1018-1172    

DOI:10.1159/000158210

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Cardiac tissue from hamster neonates was transplanted into the hamster cheek pouch. After vascularization of the transplanted tissue the vessels were tested for their ability to convert angiotensin I (AI) to angiotensin II (AII). AI caused vasoconstriction of the coronary vessels which was reduced significantly by converting enzyme inhibitor and the AII antagonist (Sar1-Ala8) angiotensin II. It was concluded that the vessels of transplanted cardiac allografts convert AI to AII in a manner similar to that observed in the whole heart indicating that this procedure provides a good model for studying the microcirculation of the heart.

ISSN:1018-1172    

DOI:10.1159/000158211

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Complex encapsulated neurovascular structures, glomus organs, occur in superficial and deep positions in many species. No direct evidence for their function exists. In skin they may serve thermoregulation but the reason for their structural complexity remains obscure. The concept of a local humoral circulatory control mechanism postulated on the basis of a very high acetylcholine content reported for human glomera coccygia has been investigated in homologous caudal glomus organs in monkey. No acetylcholine was detected. The organs contained 3-4 times the concentration of catecholamine (mainly noradrenaline) found in nearby vessels. Neither structure nor content of vasoactive component gives any support for an endocrine function.

ISSN:1018-1172    

DOI:10.1159/000158212

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The effect of estrogen and progesterone on the reactivity of isolated rabbit saphenous veins to adrenergic stimulation by norepinephrine, methoxamine, phenylephrine, and electrical stimulation and the effect of progesterone on the reactivity to barium ions were studied. 8 days after ovariectomy, a saphenous vein was removed and studied in vitro. After 1 and 4 days of hormone therapy, the contralateral vein was removed and its reactivity was compared with that of the first vein and with that of veins from untreated, sham-operated control animals. The reactivity to adrenergic and nonadrenergic stimulation was increased after 4 days of treatment with progesterone (5 mg/day); treatment for 4 days with estrogen (100 µg/day) increased the reactivity to norepinephrine, electrical stimulation, methoxamine, and phenylephrine. The results with progesterone suggest that the increased adrenergic responsiveness is not related to a mechanism controlling adrenergic transmission in veins

ISSN:1018-1172    

DOI:10.1159/000158213

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

Tissue wet weight as well as total protein content, 5’-nucleotidase activity, alkaline phosphatase activity and Ca2+ accumulation associated with a plasma membrane fraction isolated from spontaneous hypertensive rats (SHR) and rats with deoxycorticosterone (DOC) induced hypertension were investigated. Enhanced alkaline phosphatase activity and reduced ATP-dependent Ca2+ accumulation preceded the development of hypertension in SHR and these effects were reversed by DOC withdrawal followed by lowering of blood pressure in DOC hypertension. Increased arterial tissue wet weight and 5’-nucleotidase occurred only at the later stage of hypertension in SHR and the increased tissue wet weight was not reversed by DOC withdrawal in DOC hypertension. These observations suggest that enhanced alkaline phosphatase and reduced ATP-dependent Ca2+ uptake may play a significant role in initiating hypertension, while increased arterial wet weight and 5’-nucleotidase activities may participate in the maintenance of hyperte

ISSN:1018-1172    

DOI:10.1159/000158214

出版商:S. Karger AG    

年代:1979

数据来源: Karger

摘要:

The arterioles in the cremaster muscle of 8 to 10-week-old Ob/Ob, Db/Db and stroptozotocin diabetic mice are characterized by a decreased number of arterioles, loss of vascular tone and a reduced cross-sectional area of the vessel walls. The present study was designed to determine if these abnormalities persist to adult life or if additional abnormalities develop to cause vascular dysfunction. The diameters, wall thickness to lumen ratios and vessel wall areas of comparable types of innervated arterioles in 24- to 28-week-old normal and Db/Db mice are equivalent, except that the smallest arterioles of Db/Db have thin vessel walls. However, blood flow at rest is only 3.0 ± 0.9 ml/min/100 g of cremasteric muscle tissue in Db/Db mice as compared to 5.5 ± 1.3 ml/min/100 g in normal mice. After all vascular control is abolished, the arterioles of Db/Db dilated, but significantly (p < 0.05) less than in normal animals. The minimum distance between adjacent capillaries (wall to wall) during the passive state was 28 ± 1.7 µm in Db/Db mice and 21.8 ± 0.6 µm in normal mice; this indicates a major decrease of vascularity in the adult Db/Db mouse. The results obtained indicate that the reduction in numbers of arterioles and loss of vascular tone in juvenile diabetic mice persists to adult life but arteriolar wall characteristics become normal in adult

ISSN:1018-1172    

DOI:10.1159/000158215

出版商:S. Karger AG    

年代:1979

数据来源: Karger

ISSN:1018-1172    

DOI:10.1159/000158216

出版商:S. Karger AG    

年代:1979

数据来源: Karger