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Biomedical subjects

G Milne

Publications and source records attributed to G Milne.

At least 55 records · Page 3Linked to original sources
PubMed1981

The inadequacy of urinary N tau-methyl histidine excretion in the pig as a measure of muscle protein breakdown.

1. The validity of the urinary excretion of N tau-methyl histidine (N tau-MH) by pigs as an index of muscle protein breakdown in vivo was tested using the criterion of the rate of recovery of radioactivity in urine following an intravenous dose of N tau-[14CH3]methyl histidine. 2. Urinary recoveries of radioactivity from five animals were less than 21% of dose in 7 d after which the daily recovery was less than 0 . 3% per day. 3. The incomplete recoveries of radioactivity were associated with the presence in muscle of a large pool of non-protein-bound N tau-MH, the concentration of which increased with age. 4. The N tau-MH in this pool was present as free N tau-MH and in a dipeptide which constituted more than 90% of the total non-protein-bound N tau-MH. The contribution of the peptide increased with age, reaching 99. 8% in older animals. 5. The pool of non-protein-bound N tau-MH was maintained and increased in both established and newly accreted tissue by retention of some of the N tau-MH released by muscle protein breakdown, only a proportion of which was therefore available for excretion. Hence, the urinary excretion of N tau-MH is not a valid index of muscle protein breakdown in pigs.

Aging↗
PubMed1981

Effects of bile acids and hydrogen ion on the fine structure of oesophageal epithelium.

Oesophageal mucosal biopsies were incubated in 20, 0, and 0.2mM solutions of cholic, chenodeoxycholic, ursodeoxycholic, and deoxycholic bile acids. Both conjugated and unconjugated bile acids were studied at pH 1 and 7 singly and in combination. Observations were also made using 0.1 N hydrochloric acid and human gastric juice at pH 1-3 and 7-8. After incubation for up to 15 minutes the mucosa was examined under transmission electron microscopy. We concluded that high and moderate concentration of all the common bile acids damaged the oesophagus irrespective of the pH, that low concentrations of bile acids were damaging only at high acid levels, and that damage to the epithelium did not occur when the pH of the gastric juice had been raised.

Bile Acids and Salts↗
PubMed1980

Cholecystitis: a fine structural analysis.

The epithelial cells from 40 gallbladders showing chronic cholecystitis and five with cholesterolosis were examined by electron microscopy. A number of features of non-specific cytological injury were noted some of which may have been related to the disease and others to anoxia. The basement membrane showed reduplication. Intraepithelial cells were identified as lymphocytes, polymorphonuclear leukocytes, macrophages and mast cells. Lipid droplets in the epithelial cells were found in 60 per cent. of the specimens.

Basement Membrane↗
PubMed1980

The urinary excretion of N tau-methyl histidine in sheep: an invalid index of muscle protein breakdown.

1. The validity of the urinary excretion of N tau-methyl histidine (N tau-MH) in sheep as a measure of the breakdown of muscle protein in vivo was assessed from the urinary recovery of radioactivity following the intravenous administration of N tau-[14CH3]methyl histidine. 2. Recoveries of radioactivity in urine from animals of 4 weeks to 7 years of age were incomplete in 7 d but progressively increased with the age of the animal, becoming almost quantitative (90%) in older animals after recovery for 3 weeks. 3. The incomplete urinary recoveries were not due to partial excretion of N tau-MH in faeces or its oxidation and elimination in expired gases but were related to the presence in muscle of a pool of non-protein-bound N tau-MH which was several times larger than the expected daily urinary excretion. 4. This pool in newly accreted muscle tissue was maintained by retention of some of the N tau-MH released by breakdown of muscle protein. Hence, only a proportion of the N tau-MH released from protein breakdown was available for excretion. This proportion increased with the age of the animal and was probably the main determinant of the improved recoveries of radioactivity obtained in urine from older animals. 5. The non-protein-bound N tau-MH in muscle consisted of free N tau-MH and a dipeptide containing N tau-MH, the latter comprising on average approximately 82% of the total non-protein-bound N tau-MH in muscle. This proportion did not change appreciably with the age of the animal. 6. The dipeptide appeared to be synthesized in muscle from free N tau-MH and was not a terminal product of protein breakdown. 7. The results show that urinary excretion of N tau-MH is not a reliable index of muscle protein breakdown in sheep.

Age Factors↗
PubMed1979

Electron microscopic changes in human oesophageal epithelium in oesophagitis.

At the ultrastructural level the inflamed oesophageal epithelium shows a variety of lesions. These include mitochondrial damage, intracellular oedema, membrane whorls and dilation of the endoplasmic reticulum and the appearance of keratohyaline and parakeratosis granules. The basement membrane shows changes ranging from thickening to areas of loss of continuity. There is an increase in the anchoring fibrils. The spaces between the cells are enlarged and contain varying amounts of debris rich in neutral mucosubstances. There are less membrane-coated granules in the inflamed epithelium than in the normal. The intra-epithelial intrusive cells demonstrated were lymphocytes and neutrophil polymorphs.

Epithelium↗
PubMed1979

The ionic components of normal human oesophageal epithelium.

The distribution of cations and anions in normal human oesophageal epithelium has been investigated with the pyroantimonate and silver-osmium tetroxide techniques. There is a discontinuous distribution of both ions in the intercellular space. The ions are associated with various organelles, as has already been described in the literature. Specifically, in the oesophageal epithelium, there are a few deposits of pyroantimonate and occasional silver in the membrane coating granules, but here is no apparent relationship of either ion with the tonofilaments or glycogen particles. The superficial cells are leaky and contain fewer ions than the deeper functional layer cells.

Anions↗
PubMed1979

The distribution and mobility of surface anionic groups of normal human oesophageal epithelium following interaction with cationized verritin.

Oesophageal epithelial cells from biopsies from normal patients showed the presence of randomly distributed anionic groups, mostly sialic acid on the cell membrane in fixed material shown by cationized ferritin. When biopsies were pulse labelled, patching occurred in all three cell layers. Patching was energy dependent and did not occur at 4 degrees C. Pulse labelled material incubated on an unlabelled medium showed progressive loss of cationized ferritin from the cell membrane. This was mostly into the medium, although some was internalized in membrane profiles. A second pulse of cationized ferritin produced further patching suggesting regeneration of cell membrane. Superficial cells were leaky, but their organelles were not.

Anions↗
PubMed1978

Concanavalin A receptors in normal and inflamed oesophageal epithelium. A light and electron microscopic study.

We have examined normal and inflamed oesophageal biopsies for the distribution of alpha-D-mannosyl and alpha-D-glucosyl residues using the concanavalin A--horse radish peroxidase--Diamino-benzidine (DAB) technique at the light and electron microscope level. Receptors were found on the epithelial surface and in the nuclear membrane and endoplasmic reticulum. A similar distribution was found with the intrusive lymphocytes and polymorphonuclear leucocytes in the inflamed state. Some of the increased intercellular debris from inflamed biopsies contained concanavalin A receptors.

Biopsy↗
PubMed1978

Cellular junctions in human oesophageal epithelium.

The appearances of this intercellular junctions in normal and in inflamed oesophageal epithelium are described. Typical hemidesmosomes occur along the abluminat aspect of the basal cells. Desmosomes are most frequent in the prickle cell layer, where desmosome fields may occur, and in the lower functional cell layer. Their fate in the upper layers is not known. Gap junctions are few in the basal cell layer and rare in the most superficial layers. They are maximal in the prickle cell layer. Tight junctions only occur in inflamed tissue between the most superficial cells usually as part of a lateral intercellular junctional complex that also contains belt desmosomes. They may represent attempts by a non-keratinised epithelium to increase its defences against toxic luminal contents.

Cell Membrane↗
PubMed1978

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

Acid 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 micron) with tilting showed GERL to consist of anastomosing tubules.

Acid Phosphatase↗
PubMed1978

The effects of dietary nitrogen level on the collagen of rat skin.

1. Male rats of approximately 120 g body-weight were maintained on a commercial stock diet containing 204 g crude protein (nitrogen x 6.25)/kg, a hydroxyproline-free high-protein (HP) diet containing 200 g casein/kg as the only protein source, or a low-protein (LP) diet containing 40 g casein/kg. After 6 weeks on these diets half of each group was transferred to a non-protein (NP) diet and the experiment was continued for a further 6 weeks. Animals from each group were killed at 4 d, 3 weeks and 6 weeks after the transfer to the NP diet. 2. Throughout the experiment the urinary excretion of N, hydroxyproline and creatinine, and the content and solubility of the skin collagen were determined. 3. When compared with a control group killed at the beginning of the experiment the rats maintained on the LP diet showed an increase of 25% in total N content of the skin but collagen content increased by 100%. Rats transferred from the HP to the NP diet lost both N and collagen from the skin, but those transferred from the LP to the NP diet lost N but increased the collagen content by 42%. 4. Protein deprivation brought about marked changes in the solubility of the skin collagen, suggesting an increase in the rate of maturation of skin collagen.

Animals↗
PubMed1977

Mucosubstances in the normal human oesophageal epithelium. A comparison of periodic acid-silver and phophotungstic acid techniques.

Normal human oesophageal epithelium was investigated with the periodic-acid-silver methenamine technique and its variations to demonstrate neutral mucosubstances at the ultrastruct 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.

Epithelium↗
PubMed1977

An ultrastructural study of osmiophilia in normal human oesophageal epithelium.

Oesophageal biopsies were obtained from patients with normal oesophagi during fibre-optic endoscopy for upper gastro-intestinal symptoms. They were studied with the prolonged osmication technique. The forming face of the Golgi apparatus was demonstrated in the basal and lower prickle cells. These cells also showed osmium deposition in their mitochondria, endoplasmic reticulum, perinuclear cisternae and lysosomes. The capillary endothelial cells also showed osmium deposition in their Golgi apparatus and endoplasmic reticulum.

Endoplasmic Reticulum↗