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Dive into the research topics where G. Milne is active.

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Featured researches published by G. Milne.


Histochemical Journal | 1984

Microwave fixation: Its potential for routine techniques, histochemistry, immunocytochemistry and electron microscopy

D. Hopwood; G. Coghill; J. Ramsay; G. Milne; M. A. Kerr

SummaryHuman tissues, both biopsy and postmortem, and tissues from rodents were fixed by microwaves at various temperatures and compared against formaldehyde-fixed material. Conventional stains, including trichromes, worked well. Red cell were lysed, but white cells were fixed, thus permitting diagnoses of various inflammatory states. Malignant cells were equally well-preserved by the two methods. Histochemical investigations of mucosubstances, lipids and various hydrolases showed no significant difference between the two techniques. Some neurological stains, however, were not as good following microwave treatment. Immunocytochemical localization of IgA, IgM and IgG showed no significant difference after microwave fixation compared to that in tissues fixed with formaldehyde. Microwave fixation did not lead to a greater tissue shrinkage than that obtained with formaldehyde fixation. Both were significantly less than that following treatment with phosphate-buffered saline alone. Electron microscopy gave results which were interpretable, but with damage resembling early postmortem change. Microwave fixation is complete in approximately 1–2 min.The mechanism of fixation appears to be due to denaturation associated with disulphide bond formation and a decrease in solubility of proteins.


Histochemical Journal | 1988

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

D. Hopwood; G. Yeaman; G. Milne

SummaryAlkaline 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 clevage or polymerization of lysozyme or haemoglobin. Protein formaldehyde reaction mixtures produced protein polymers between 0° and 40°C which could be separated by SDS-polyacrylamide gel electrophoresis. Microwave irradiation of lysozyme or haemoglobin plus formaldehyde on icebath up to 30 min produced a similar electrophoretic pattern. When lysozyme or haemoglobin plus formaldehyde was heated to 60°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.


Histochemical Journal | 1977

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

Kathleen R. Logan; D. Hopwood; G. Milne

SynopsisThe 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.


Histochemical Journal | 1990

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

D. Hopwood; G. Milne; J. Penston

SummaryMicrowaves have been used to stabilize tissues from the gastrointestinal tract for scanning electron microscopy. The temperature reached is important. Above 55–60°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°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°C. Tissues fixed in boiling formaldehyde retain a surprisingly good morphology.


Histochemical Journal | 1978

The light and electron microscopic distribution of acid phosphatase activity in human normal oesophageal epithelium

D. Hopwood; Kathleen R. Logan; G. Milne

SynopsisAcid phosphatase activity in human normal oesophageal epithelium was studied with light and electron microscopic techniques. The maximum activity was found to be in the prickle and lower functional layers. Electron microscopic examination revealed activity to be localized in GERL, lysosomes and membrane coating granules. These last structures probably secreted their content into the intercellular space in the central part of the functional layer. Thick sections (0.5 μm) with tilting showed GERL to consist of anastomosing tubules.


Histochemical Journal | 1984

The uptake of cationized ferritin by guinea-pig gall bladderin vitro

M. S. Elhamady; G. Milne; D. Hopwood; P. E. Ross; Ian A.D. Bouchier

SummaryTissue pieces of guinea-pig gall bladder were grownin vitro for up to ten days. Over this period at different intervals, specimens were exposed to cationized ferritin in culture medium for 1 h and then grown in ferritin free medium for up to 24 h. Other specimens were grown in culture medium containing cationized ferritin for up to 24 h. Both treatments produced a similar morphological sequence. Electron microscopy at all intervals studied showed the cationized ferritin was first bound by the apical cell membrane, clumped and internalized in large 400 nm vesicles. It was then carried to lysosomes in the region of the Golgi apparatus. Within 1 h, the marker was exocytosed in clumps into the lateral intercellular space, accumulating against the basement membrane in a roughly regular approximately 60 nm array. This pathway of cationized ferritin through the gall bladder epithelium is the same as that followedin vivo although the time taken was shorterin vitro.


Archive | 1977

Mucosubstances in the normal human oesophageal epithelium

D. Hopwood; Kathleen R. Logan; G. Milne

SummaryNormal human oesophageal epithelium was investigated with the periodic acid — silver methenamine technique and its variations to demonstrate neutral mucosubstances at the ultrastructural level. The results were compared with the acid phosphotungstic acid method. Neutral mucosubstances were shown in the cell coat and membrane coating granules by both techniques. The silver methods also demonstrated glycogen, the Golgi apparatus and dense bodies. The periodic acid — silver methenamine technique outlined positive material in the intercellular space of the prickle cell layer, but the other silver methods did not.


Histochemical Journal | 1994

Secretory and absorptive activity of oesophageal epithelium: evidence of circulating mucosubstances

D. Hopwood; G. Milne; Janusz Jankowski; K. Howat; David Johnston; K. G. Wormsley

SummaryThe space between the oesophageal basal and prickle epithelial cells appears empty by standard ultrastructural preparative techniques. Fixation of human oesophageal biopsies with a variety of agents, including tannic acid, glutaraldehyde—lysine, cetylpyridinium chloride and Ruthenium Red shows that this space is filled with mucosubstances, some free, some attached to the cells as a glycocalyx. There is evidence that this material is secreted constitutively by the basal and prickle cells. This secretion may be changed or blocked by incubating oesophageal biopsies in the presence of colchicine or dinitrophenol. Incubation at 16°C has the same effect. Absorption from the intercellular space may be followed using the fluid phase marker, horseradish peroxidase. Early endosomes may also be shown by their acid phosphatase activity. Incubation of biopsies at 20–22°C allows early endosomes to accumulate material, but not pass it on the late endosomes.


Histochemical Journal | 1991

Uptake of horseradish peroxidase by human oesophageal explants over 24 h

D. Hopwood; G. Milne; Janusz Jankowski; Karen Howat; K. G. Wormsley

SummaryHuman oesophageal biopsies, endoscopically and histologically normal, were incubated in Hams F10 for periods up to 24 hours in the presence of horseradish peroxidase. The fluid phase marker was taken up most avidly by the prickle cells but to a lesser extent in the functional layers and by basal cells. Endocytosed markers proceeded to multivesicular bodies (segrosomes). Horseradish peroxidase was later deposited in lysosome-like structures and also in the Golgi apparatus. The lesser uptake by the functional cells may represent reduced access of the marker to the cells due to the intercellular barrier.


Histochemical Journal | 1986

Effects of colchicine on the gallbladder of the mouse

D. Hopwood; G. Milne; P. E. Ross; A. Clark; R. A. B. Wood

SummaryThe effects of colchicine on the mouse gallbladder followed a course depending on the dosage given (0.4–4 mg/100 g body weight). Following 0.5 mg/100 g, by 16 h there was a marked cholestasis with dilatation of the gallbladder and steatosis. There were progressive alterations in the Golgi apparatus and accumulation of vesicles. The apical mucous droplets decreased in number and became pleomorphic and dispersed throughout the cytoplasm. Lipid droplets appeared in numbers on the epithelial cytoplasm. By 48 h the tissues had reverted to normal appearances. When cholecystokinin, pilocarpine or ceruletide were given to animals which had received colchicine 18 h previously, the excess bile from the dilated gallbladder was discharged into the duodenum, remaining apical mucous droplets secreted and electron dense material accumulated in the lateral intercellular space. This formed a quasi-regular array between the epithelial bases and the basement membrane. Biochemically there was a significant decrease in alkaline phosphatase activity and a significant increase in acid phosphatase activity.

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Janusz Jankowski

University of Central Lancashire

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