Fluoreszenz-polarisationsmikroskopische Analyse der Ultrastruktur von Elastikalamellen und Elastikafasern

Permeability of intracranial blood vessels to endogenous serum albumin

The blood-brain barrier to endogenous serum albumin labeled with Evans blue was studied by standard fluorescence microscopic techniques in cats. Systematic studies confirm that, except in certain well-known loci (hypothalamic median eminence, subfornical organ, area postrema, etc.), blood vessels within brain tissue are impermeable to endogenous albumin. But studies also demonstrate that in virtually all arteries at the base and over the surface of the brain and brain stem, labeled albumin passes readily through endothelium and the vascular wall to the adventitia. These observations are discussed in the context of current concepts of intracranial vascular permeability and, in terms of general biology, the possible consequences of the permeability to serum albumin of intracranial, extraparenchymal blood vessels on the composition and physiology of cerebrospinal fluid and in the pharmacokinetics of antibiotics, anticonvulsants, and antineoplastic and vasoactive agents.

Intimal thickening of human femoral arteries with special regard to elastin, Part 1. Diffuse intimal thickening due to growth and age

In infants, human femoral arteries display seam-like internal elastic lamina (IEL) covered with endothelium on the luminal side and with smooth muscle cells (SMC) on the medial side. At birth the growth of IEL is finished, correlated with a loss of microfibrils (MF) at the periphery. With the onset of the postnatal vessel growth the joints of IEL seem to be mechanically widened until they have the appearance of gaps with progressing age. After the age of 40 years there are often rod-like crystallites in the IEL, probably composed of cholesterol esters. A small first consecutive lamina (CL) can be seen already in childhood; it enlarges until the 3rd decade of life and is interpreted as a substitute to the "fragmented" IEL. After the 5th decade of life the first CL is arranged within the intima at a certain distance from the IEL and consisting of loosely arranged elastic fibrils. In very old arteries (beyond the 8th decade of life) gaps are rarely seen in the first CL. In individuals over the age of 30 years, the space between IEL and the first CL is occupied by smooth muscle cells (SMC) which are tightly packed. Additional CLs above the first CL can be found in elderly individuals, there CL obviously contribute to the intimal thickening. The ultrastructure of the elastic elements of the vessel wall and their possible function are discussed.