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Biomedical subjects

U Mayer

Publications and source records attributed to U Mayer.

125 records · Page 7Linked to original sources
PubMed1977

[Different types of cells in tissue cultures of normal bovine iris (author's transl)].

Calf iris tissue cultured in TCM 199 was studied under the electron microscope at 5, 14, and 21 days. Melanocytes and clump cells (macrophages), and mast cells could be distinguished, as well as fibroblasts, round cells, and non striated muscle cells, Melanocytes lost their pigment granules temporarily, but not their ability to produce new ones again after a certain adaptation period. The morphology of clump and mast cells was only slightly altered. In incubation, fibroblasts and round cells were found to have spheroid surfaces. After a 3 week's culture, muscle cells showed signs of growth.

Animals↗
PubMed1976

[Biomicroscopic aspects of normal iris tissue in culture (author's transl)].

The cells shown were cultivated from iris pieces of 1-5 mg wet weight incubated in TCM 199 after adding 20% calf serum and antibiotics. Different morphologic aspects allowed some coordination of the cells to the corresponding iris layer. Even after 1 year's incubation, fibroblastic stroma cells showed a radiate growth from the insemination point. Pigment cell-like elements were packed with yellowish, bright, and intensely refracting spherical bodies, indicating a specific function. An analogous finding in the human eye after a perforating iris lesion was growth of chromatophores on the anterior lens capsule.

Animals↗
PubMed1976

[The influence of cortisone upon the metabolism of surviving lens epithelia and iris tissue (author's transl)].

Warburg experiments showed the oxygen consumption by lens epithelium and iris tissue without and after addition of 4 mg methylprednisolone to 100 cc medium. In the last case the O2-uptake of the epithelium seemed diminished, that of the iris tissue showed significantly reduced to 50%. The determination of the consumption of glucose was done by measuring its level in the medium before and after a 5 day's incubation, without and after addition of 4 mg-% of methylprednisolone, by means of the "Merckotest". The consumption of the epithelia lowered to 1/6; contrarily rose that of the iris tissue significantly to the double amount. The metabolism of the iris tissue showed a good adaptation in compensating a lower respiratory activity by a augmented glycolysis, which is impossible to the lens epithelium. This may be one of the factors inducing a cortisonic cataract.

Culture Techniques↗
PubMed1976

[The action of pilocarpine on the metabolism of surviving lens epithelium and iris cells (author's transl)].

In tissue culture, lens epithelia and iris cells survive concentrations of 0.5 mg pilocarpine/100 ml TCM, even better those of 0.25 mg/100 ml. By means of the Warburg-method and Boehringer's Glukotest, the consumption of oxygen and glucose were measured without and with the addition of pilocarpine. The oxygen-uptake of the epithelia decreased to one third after addition of the drug, while it doubled in the iris cells. This reveals a compensating effect of the iris tissue protecting the epithelia. Pilocarpine inhibited the consumption of glucose in both tissues, but not significantly. Consequently, we are not dealing with a cataractogenuous substance. This gives new light upon Hockwin's so-called "Additions-katarakt".

Cataract↗
PubMed1975

[Studies on tissue cultures from calf eyes].

The growth of lens epithelium and iris tissue was studied by biomicroscopy and electronmicroscopy, its velocity measured. With the Warburg-method it was possible to show the oxygen-uptake of both tissues without and after addition of different substances. Pilocarpine lowered the O2-uptake of the epithelia to less than 1/3 of its normal value, whilst it raised that of the iris to the double amount. Napthochinone inhibited the O2-uptake of both tissues to little more than half of the normal level. The least differences as compared to the controls showed methyl-prednisolone: it lowered scarcely the O2-uptake of the epithelium, and the O2-uptake of the iris to almost half the normal rate. The author concludes that cataract developes, if oxygen-uptake of lens epithelium and iris tissue are reduced in the same way without any possibility of compensation. Under certain conditions this cell-biological method may be employed to detect cataractogenous substances.

Animals↗