摘要:

Adrenergic-induced vasoconstrictions are succeeded by an adjustment reaction (‘escape phenommenon’ or ‘autoregulatory escape’) and after the end of stimulation by a postconstrictive dilation (‘reactive hyperemia’)- These vascular reactions have been examined on the intact mesenteric circulation of the cat by performing frequency-response curves (5 and 10 V, 1 msec. 1–50 Hz). An electrotonic blockade and a local summation could be excluded as the cause of the escape within the physiological range. The maximum of the initial reaction was found at a stimulation strength between 12 and 16 V (10 Hz, 1 msec). The maximum of the escape reaction occurred at 5 V. Both vascular reactions were strongly dependent on the local concentration of noradrenaline (i.a. infusion); however, they reached their maximum at different concentrations. The escape reaction is apparently a persisting adjustment to a steady state. Despite a formal similarity, no correlation could be demonstrated between the postconstrictive dilation and the escape reaction. Both vascular adjustment reactions are of myogenic origin. It is concluded that the reason for the escape phenomenon can not be found in the local or propagated nerval response, in the transmitter release, or in its effect on the vascular smooth muscle. But it is suggested that the escape reaction is a form of myogenic, autonomic adjust

ISSN:1018-1172    

DOI:10.1159/000157979

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

In rabbits subdivided in three groups of different age, vitalmicroscopic investigations were performed concerning the comparative studies of the microcirculation and microvessel permeability for proteins. The normal brightfield, incomplete darkfield, and bluelight luminescence techniques were used. Young rabbits showed a typical pattern of protein permeation mainly localized on the venous end of the capillary bed with maximum along the venules and participation of capillaries and small collecting veins. The postcapillary blood flow was marked by a considerable instability because of increased tendency to red cell aggregation and blood flow anomalies. The findings obtained in middle-aged rabbits were similar to the results of young rabbits. The findings in the third group of old animals, however, were clearly different in comparison with group 1. The protein permeability remained restricted on the venules and was remarkably diminished. Consequently, the intravascular luminescence persisted for 1 h and more, and the small vessels appeared very sharply delimitated against the extravascular space because of absence of a perivascular luminescence. The postcapillary blood flow seems to be stabilized, and prestasis was extremely rare. The diminution or absence of a protein passage across the capillary wall and interstitial space of old animals is interpreted as an important component responsible for the aging process of tissues and organs.

ISSN:1018-1172    

DOI:10.1159/000157980

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

The equations of state for the forces acting between the intra- and extracapillary spaces have been developed, and their significance in the filtration and reabsorption properties of the blood capillaries are shown.

ISSN:1018-1172    

DOI:10.1159/000157981

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

An instrument with which the four relevant forces for filtration and reabsorption of the blood capillary can be balanced, is described as a demonstration model.

ISSN:1018-1172    

DOI:10.1159/000157982

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

In 37 aortae of sheep fetuses of various ages, the medial vasa vasorum were investigated. The aortic segments which had more than 29 medial lamellar units displayed medial vasa vasorum. This occurred in the second month of gestation for the ascending and descending segments, and in the fifth month for abdominal aorta.

ISSN:1018-1172    

DOI:10.1159/000157983

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

In the present paper on impedance functions, additional proof is presented for active participation of wall muscles in the carotid circulation. If arteries behave like passive elastic ducts, then the frequency dependance should not depend on the range of frequencies used. But this only held forarteries which had been previously treated with N-ethylmaleinimid in order to paralyze the muscular activity.

ISSN:1018-1172    

DOI:10.1159/000157984

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Lymphatic porosity was produced by feeding rats a diet, lacking from the vitamins of the B group. Coumarintroxerutin (Venalot®) treatment has been found to prevent this abnormality. Pathophysiologic and therapeutic implications of these findings are discussed

ISSN:1018-1172    

DOI:10.1159/000157985

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

A case of a saccular aneurysm of the venous limb of an internal A-V fistula of the forearm is described. It developed a month after its creation and following the fourth dialysis. The mechanism of formation of the rare aneurysms of the venous limb central to arteriovenous fistulas is presumed to be increased blood pressure and flow of long duration. In this case, the cause is considered to be trauma by the needle during hemodialysis.

ISSN:1018-1172    

DOI:10.1159/000157986

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

Electron microscopy of 18 human pituitary adenomas revealed vascular abnormalities consisting of thickening of endothelial lining, endothelial swelling, endothelial blebbing, accumulation of microfilaments in the cytoplasm of the endothelial cells, partial or total loss of fenestration, and, rarely, thickening of basement membrane. Disturbance of pituitary microcirculation, possibly due to alteration of intrahypophysial pressure, can result in hypoxia. This might play an important role in the genesis of changes of vasculature. Lesions of the pituitary vessels occur not infrequently. If severe, they may interfere with exchanges of O2 and metabolic products and may alter permeability across the vascular walls. Their further progress may cause irreversible damage to the tumor cells, leading ultimately to hemorrhage and infarction of the tumor.

ISSN:1018-1172    

DOI:10.1159/000157987

出版商:S. Karger AG    

年代:1973

数据来源: Karger

摘要:

The angiographic features of leiomyomatous tumors of the small bowel are described in three cases. Selective celiac and superior-mesenteric angiography disclose large, sometimes multiple, feeding arteries and draining veins. There are many irregular tumor vessels and dense staining, venous pooling and early venous filling. The margins are well circumscribed and correspond to the true size of the mass. The differential diagnostic problems between benign and malignant leiomyomatous lesions and the angiographic features of metastatic leiomyosarcoma in the omentum and the liver are also described.

ISSN:1018-1172    

DOI:10.1159/000157988

出版商:S. Karger AG    

年代:1973

数据来源: Karger