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A Castenholz

Publications and source records attributed to A Castenholz.

At least 37 records · Page 2Linked to original sources
PubMed1984

[Structural picture and mechanism of action of the "initial lymph system"].

The general structural features of the initial lymphatics are exhibited in the view of light and electron microscopic findings. Special attention was given to recent results in scanning electron microscopy. As regards the terminology of the initial lymphatic structures, it is suggested that the term "initial lymphatic sinuses be used" instead of "initiale Lymphbahn" designated a functional unit consisting of the initial lymphatic sinuses including the prelymphatic interstices and precollecting vessels. In addition to the functional hypotheses, so far made for the mechanism of action of the initial lymphatics, a further aspect is considered based on the active cooperation of the vessels in lymph formation evoked by the contractile properties of the lymphatic endothelium.

Animals↗
PubMed1983

Visualization of periendothelial cells in arterioles and capillaries by scanning electron microscopy of ultrasound treated and plastoid injected brains in rats.

The periendothelial cells of small arterioles and capillaries - smooth muscle cells and pericytes - are represented in the SEM after ultrasound treatment and by microcorrosion resin casts of the rat brain. The morphological appearance of the periendothelial cells revealed by both methods is nearly identical. In ultrasound treated tissue the cells of the medial tunic themselves become apparent as the adventitial material of the vascular wall is removed. Predominantly the pattern of arteriolar smooth muscles occurs in this manner. In casts the cells are represented and replaced by corresponding plastic structures. The pericytes of the capillaries and even the precapillary sphincters can be demonstrated in these preparations. SEM in conjunction with the applied techniques gives new knowledge of the cytoarchitecture and function of the vascular wall in microvessels.

Animals↗
PubMed1983

The outer surface morphology of blood vessels as revealed in scanning electron microscopy in resin cast, non-corroded tissue specimens.

In Mercox-filled, non-corroded tissue the blood microvessels maintain the tubular shape they have in the intact circulation. Preparations treated in this manner are especially suited to reveal the fine structural features of the outer vascular wall and its relationship to the extravascular space in SEM. The outer wall morphology of small arteries, arterioles, true capillaries, and sinusoids is demonstrated in mesentery, skeletal muscle, pancreas, liver, and kidney of the rat. In fractured specimens of cast liver tissue the outer sinusoidal wall and the adjacent lacuna surface can be well visualized from the view of the space of Dissé. In kidney, the glomerular filtration membrane becomes accessible from the sight of the urinary space. This technical approach may contribute to improve the knowledge of a special field of vascular wall research to which little attention has previously been paid.

Animals↗
PubMed1980

Formation and morphology of Reissner's fibre in primates. A scanning electron microscopic study.

The subcommissural ependyma of the third ventricle, the rhomboid fossa, and the central canal of the spinal cord were examined in Tupaia, Saimiri, and Cebus by scanning electron microscopy. In all three species studied, fine filaments, granules, and amorphous masses were found at the surface of the subcommissural ependyma representing the original structures of the Reissner's fibre (RF). Bundles of filaments or net-like structures ultimately forming a compact secretory plate develop in the caudal part of the secretory zone. In Tupaia and Saimiri, the secretion collects in a groove-like depression in the centre of the dorsal ventricular wall. In Cebus two secretory pathways occur in the lateral sulci, which eventually merge together in the aqueduct. In the rhomboid fossa and the spinal cord, the RF is in close contact with the ependyma, and its surface is longitudinally grooved and covered with granular material and cells. The present scanning electron microscopic findings speak in favour of a merocrine type of secretion in the apical region of the ependymal cells. Ciliary movement and flow of cerebrospinal fluid are assumed to be the most important factors regulating the formation of the RF.

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PubMed1978

[Morphometry and histology of the eye of Callimico goeldii (Thomas 1904, callimiconidae primates) (author's transl)].

The histologic anatomy of the eye of Callimico goeldii is described and histometric data are communicated. The retina is treated with special attention. The eye of Callimico features all characteristics of a visual organ adapted to diurnal activity as is known from many higher primates and man. The well-differentiated Fovea centralis and the numerical relations of the three retinal neurons, which are clearly reduced from the periphery towards the center of the retina, indicate a particularly high degree of centralization ("Zentralisationsstufe" sensu Rohen). Similar numerical relations are found in the taxonomically related families Cebidae and Callithrichidae. A high degree of centralization is understood to facilitate a good visual resolution. The eyelid apparatus is differentiated like in other higher primates. The eye muscles contain extraordinarily many nervous-muscular entities that are interpreted to serve as nervous regulatory functions. The histologic results relate well with certain behavioral phenomena of this species.

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PubMed1977

Studies on the "vascular labeling" phenomenon in the iris and the ciliary body of the rat after intravenous injection of colloidal carbon.

The occurrence of carbon deposits after intravenous injection of colloidal carbon (vascular labeling phenomenon) in the iris and the ciliary body of the rat eye was studied by vital microscopy, unstained perfused mount preparations, and by electron microscopy. Generally in the untouched eye the vascular labeling phenomenon is either absent or appears only in the form of finest granular deposits in some capillaries and venules of the iris and the ciliary body. A decrease of intraocular pressure by paracentesis causes a certain blackening phenomenon, which prefers the capillaries and the venules of the iris and the capillaries in the ciliary processes. This effect is intensified by a further decrease of the intraocular pressure to -30 mm Hg. Predominantly the deposits are found stronger in the ciliary region than in the iris. Increase of the intraocular pressure of up to 30 mm Hg diminishes the blackening phenomenon. After administration of the vasodilator bencyclane into the anterior chamber the vascular labeling phenomenon shows a clear graduation of carbon affinity depending upon the concentration of the drug: The capillaries and venules are exclusively blackened at low concentrations, additionally the collecting venules and arterioles are influenced at medium and high doses. By electron microscopy an intraluminal as well as an intramural (subendothelial) deposition of carbon, partly accompanied with signs of hemoconcentration, can be seen. Extravascular position of carbon material is seldom observed and restricted to a state of abnormally high vascular permeability. The observations give evidence for a 'gradient of permeability' between the different types of vessels of the terminal anterior uveal vascular system and also permit the assumption that the vessels of the ciliary processes are more permeable than those of the iris.

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