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Biomedical subjects

V L VAN BREEMEN

Publications and source records attributed to V L VAN BREEMEN.

13 recordsLinked to original sources
PubMed1958

Electron microscopic observations on spinal ganglion cells of Rana pipiens after injection of malononitrile.

Spinal ganglionic cells of Rana pipiens were studied with light and electron microscopes in normal animals and in animals which had received graded dosages of malononitrile intraperitoneally. After treatment no increase in the intensity of staining was noted in the Nissl substance when spinal ganglion cells were examined with the light microscope. The electron micrographs demonstrated the following in malononitrile-treated animals: 1. The cisternae of the endoplasmic reticulum composing the Nissl bodies appeared to fragment and lose their parallel orientation. 2. The microvesicular components of the Golgi complex appeared to increase in number, and the increase was apparently due to fragmentation of the membrane system of the Golgi complex. 3. The mitochondria enlarged and became pleomorphic, but displayed no alterations of internal structure. The morphological changes may be interpreted as reflections of biochemical alterations.

Animals↗
PubMed1956

Observations on the basement membranes in rat kidney.

Basement membranes in the kidney are made up of a homogeneous matrix. In argyria, silver passes from the blood in the ionic form and diffuses into the kidney basement membranes in which it is precipitated. X-ray diffraction studies of "silver-stained" rat kidneys show that most of the silver in the kidneys is combined with some form of sulfur. Histochemical staining for sulfhydryls and disulfides demonstrates the presence of these groups in basement membranes. It appears that silver ions combine with either or both the sulfhydryl or disulfide groups in the basement membranes and also in mitochondria (when the silver diffuses into a cell).

Animals↗
PubMed1955

Silver deposition in the central nervous system and the hematoencephalic barrier studied with the electron microscope.

For the purpose of studying the hematoencephalic barrier as it is concerned with silver circulating in the blood stream, silver nitrate was vitally administered to rats in their drinking water over periods of 6 to 8 months. The cerebrum, cerebellum, medulla, area postrema, and choroid plexus were prepared for light and electron microscopy. Silver deposition was found in the perivascular spaces in the choroid plexus, area postrema, in the medulla surrounding the area postrema, and in minute quantities in the cerebrum, cerebellum, and most of the medulla. Two levels of the hematoencephalic barrier were apparently demonstrated in our investigations. The endothelial linings of the vessels in the cerebrum, cerebellum, and medulla constitute the first threshold of the hematoencephalic barrier (specifically here, blood-brain barrier). The cell membranes adjacent to the perivascular spaces form the second threshold, as follows:-the neuroglial cell membranes in the cerebrum, cerebellum, and medulla (blood-brain barrier); the membranes of the neuroglial cells in the area postrema (blood-brain barrier); and the membranes of the epithelial cells of the choroid plexus (blood-cerebrospinal fluid barrier). This study deals with silver deposition and does not infer that the penetration of ionic silver, if present in the blood stream, would necessarily be limited to the regions described. Bleb-like structures were observed to cover the epithelial cell surfaces in the choroid plexus. They may be cellular projections increasing the cell surface area or they may be secretory droplets.

Animals↗