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J O Nörgaard

Publications and source records attributed to J O Nörgaard.

5 recordsLinked to original sources
PubMed1983

Renal enlargement: comparative autoradiographic studies of 3H-thymidine uptake in diabetic and uninephrectomized rats.

Incorporation of 3H-thymidine into renal cortical tissue has been studied by light microscopic autoradiography in streptozotocin-diabetic rats, uninephrectomized rats, uninephrectomized diabetic rats, insulin-treated diabetic rats and control rats. The percentage of labelled cortical nuclei (the labelling index) was determined separately in glomeruli, proximal tubules and distal tubules after 2, 4 and 6 days on autoradiographs from 1 micron thick plastic embedded sections. The incorporation of thymidine in glomerular nuclei was consistently low (less than 1%) and no differences were found between the control and experimental groups. In both proximal and distal tubules an increase in thymidine incorporation was seen on day 2 followed by a decline on days 4 and 6. The maximal labelling on day 2 in proximal tubules was 9.1% in the uninephrectomized diabetic group, 3.7% in the diabetic group and 1.4% in the uninephrectomized group. In distal tubules the corresponding values were 5.2, 3.5 and 1.1%. The increase in kidney weight after 6 days was 83, 62 and 37%, respectively. Estimates of the net increase in the number of cortical tubular cells in the different experimental groups showed that the kidney enlargement followed different patterns with respect to the extent of cellular hyperplasia and hypertrophy. The kidney growth in uninephrectomized diabetic rats was dominated by tubular cellular hyperplasia, in the diabetic group hyperplasia and hypertrophy participated to approximately the same extent, whereas cellular hypertrophy was most pronounced in the uninephrectomized animals. Nuclear labelling in the insulin-treated diabetic rats was not different from that of control rats and consequently a hyperplastic effect of streptozotocin can be ruled out.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Light microscopic visualization of colloidal gold on resin-embedded tissue.

RNase labeled with colloidal gold was used as a model for the present technique evolved for the light microscopic localization of gold-labeled substances in semithin resin-embedded sections. Tissue sections placed on glass slides were treated with the gold-enzyme complex and subsequently exposed to a photographic developed containing silver lactate. During the development gold particles are encapsulated in growing shells of metallic silver and gradually made visible in the light microscope. The amplification method can be applied to paraffin-embedded and frozen sections as well. This technique may prove useful as a supplement to studies utilizing colloidal gold or silver as markers normally used at the electron microscopic level.

Animals↗
PubMed1983

Cellular outgrowth from isolated glomeruli. Origin and characterization.

The incorporation of 3H-thymidine by isolated decapsulated glomeruli from pigs was studied up to 5 days after explantation by light and electron microscopic autoradiography. The visceral epithelial cells (VEC) were the only cell type to be labeled during the first 2.5 days, showing that this tracer can be applied as a specific marker for VEC in decapsulated glomeruli. From the third day, label was incorporated by another cell type, probably mesangial cells. Labeling of endothelial cells could not be observed. Isolated glomeruli were then incubated for 2.5 days with 3H-thymidine in order to label the VEC, and after 5 to 6 days the primary outgrowth of cells appeared. Light and electron microscopic autoradiography performed in situ showed that the majority of cells in the primary outgrowth consisted of labeled cells, thus showing their origin from the VEC. The VEC in culture appeared as very large, irregular cells with a slow proliferation rate. After 9 days of culture another cell type was seen in the outgrowth (type II cells), probably derived from the mesangial cells. This cell grew in multilayers and had a close similarity to smooth muscle cells in culture, with thick bundles of microfilaments in the periphery of the cell and an abundant intercellular matrix. A third cell type (type III) with a regular angulated, "epitheloid" shape was rarely seen in the outgrowths. Because 1 to 2% of the isolated glomeruli were encapsulated, the parietal epithelial cell is suggested as the mother cell for this cell type; this is also thought to be true because the parietal epithelial cell showed 3H-thymidine incorporation in autoradiographs of intact glomeruli.

Animals↗