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Biomedical subjects

G Milne

Publications and source records attributed to G Milne.

67 records · Page 4Linked to original sources

Ultrastructural demonstration of cell coat on the cell surfaces of normal human oesophageal epithelium.

The cell coat in human oesophageal biopsies was studied with Alcian Blue, Ruthenium Red, Safranin O, colloidal iron and the ferrocyanide--osmium tetroxide techniques. Alcianophilic material was found on the cell surface of the basal, prickle cell and functional layers, being most abundant on the superficial cells where it appeared as a continuous coat. In the deeper layers, it tended to have a particulate distribution. Some membrane-coating granules were alcianophilic. Ruthenium Red had a particulate distribution over all cell surfaces. Intercellular debris was also stained. Safranin O produced no staining. Colloidal iron stained the cell coat in a particulate manner. The ferrocyanide--osmium technique showed a uniform filamentous cell coat. The oesophageal epithelial cell coats are, in part, acid mucosubstances which, on the surface cells, may have a protective function.

Cell Membrane↗

Differentiating the effects of microwave and heat on tissue proteins and their crosslinking by formaldehyde.

Alkaline phosphatase activity in mouse liver blocks, cooled by an ice-bath, decreased by 50% in 5 min of microwave irradiation (280 W). This loss of protein tertiary structure has been mirrored by ultrastructural changes in the same tissue. Microwave irradiation did not produce cleavage or polymerization of lysozyme or haemoglobin. Protein formaldehyde reaction mixtures produced protein polymers between 0 degree and 40 degrees C which could be separated by SDS-polyacrylamide gel electrophoresis. Microwave irradiation of lysozyme or haemoglobin plus formaldehyde on ice-bath up to 30 min produced a similar electrophoretic pattern. When lysozyme or haemoglobin plus formaldehyde was heated to 60 degrees C for 30 min, the protein polymers migrated faster on electrophoresis, suggesting a smaller hydrodynamic volume than expected due to intramolecular crosslink formation, not opened up under the conditions of electrophoresis.

Alkaline Phosphatase↗

A comparison of microwaves and heat alone in the preparation of tissue for electron microscopy.

Microwaves have been used to stabilize tissues from the gastrointestinal tract for scanning electron microscopy. The temperature reached is important. Above 55-60 degrees C, epithelial cell sheets begin to lift revealing the underlying basement membrane. These cells may be recovered from the supernatant by micropore filtration or the celloidin sock technique. At higher temperatures, produced either by microwave irradiation or in a water bath, more enterocytes are released. The epithelial cells are larger with increasing temperatures, less with microwaves than with heat alone or in the presence of formaldehyde. At 70 degrees C and above, some proteins are lost and there is false localization of RNA. Some immunoperoxidase reactions are still positive after exposure of the tissue to 60 degrees C. Tissues fixed in boiling formaldehyde retain a surprisingly good morphology.

Animals↗

Transitional cell carcinoma of the renal pelvis metastatic to the metacarpal. A case report correlating cytologic and histologic findings.

This report describes the cytologic, radiologic and histologic findings in a 76-year-old male who presented with a pathologic fracture of the first metacarpal bone as the result of metastatic transitional cell carcinoma. The primary neoplasm was sited in the right renal pelvis. Metastases were also detected in the liver and confirmed cytologically. Problems encountered with the cytologic diagnosis are explained by correlation with the histologic findings. The case also illustrates the importance of clinicopathologic correlation when interpreting fine needle aspiration biopsies.

Aged↗

A metalloproteinase, capable of destroying cultured brain tissue isolated from rat glioma cells.

A continuous rat glioma cell line, BT5C, which causes severe invasion and tissue destruction when cocultured with fetal rat brain aggregates, secreted into the culture medium a metalloproteinase in a hMr latent (86000) and an lMr active (76000) isoform. Purified preparations of the enzyme were added to cultures of fetal rat brain aggregates, which were then examined by light and by scanning electron microscopy. After 48h of enzyme exposure, destruction of the neural tissue was observed. This was morphologically similar to the tissue destruction seen when BT5C spheroids were cocultured with brain aggregates. The protease had no effect on the morphology of BT 5C tumour spheroids. The report suggests a possible role of metalloproteinases in tissue degradation during brain tumour invasion.

Animals↗