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Biomedical subjects

B F Sansom

Publications and source records attributed to B F Sansom.

12 recordsLinked to original sources
PubMed1979

The half-life of glutamate dehydrogenase in plasma of dry and lactating dairy cows.

The clearance of glutamate dehydrogenase from plasma was measured weekly for three weeks in three dry and three lactating cows. The clearance was exponential with a mean clearance constant of 0.0488/j and means (+/- SE) half-life of 14.2 (+/- 0.77) h. There were variations among cows and among measurements in the same cow but there was no difference between the mean half-lives of GDH in lactating and dry cows. Because of the long half-life the small variations among individual cows are unlikely to affect the interpretation of increased plasma GDH activity.

Animals↗
PubMed1978

A field trial of 1alpha-hydroxycholecalciferol (1alpha-OH D3) in the prevention of milk fever.

The efficacy of 1alpha-OH cholecalciferol for the prevention of milk fever has been tested in a controlled field trial using 597 cows on 19 farms all of which had previously had a high incidence of milk fever. Of 293 cows receiving 1alpha-OH cholecalciferol 34 had milk fever and of 304 control cows 51 had milk fever. Although there was an apparent efficacy of 31 per cent the difference in incidence was not statistically significant. There was no effect if 1alpha-OH cholecalciferol was administered less than 24 hours before the cows succumbed to milk fever. However, if 1alpha-OH cholecalciferol was administered more than 24 hours and less than one week before the occurrence of milk fever the efficacy increased to 61 per cent and the effect was highly significant.

Animals↗
PubMed1978

The absorption of dietary manganese by dairy cows.

Additional manganese, sufficient to increase the dietary concentration to approximately 1000 mg/kg, was administered to one cow for four and another for seven days. Manganese concentrations in portal and mesenteric plasma were increased by a mean of 3.9 microgram/litre above the concentration in systemic plasma. This increment is equivalent to the absorption of 0.54 per cent of the administered manganese. The cow which received manganese for seven days showed after six days larger increases in systemic plasma manganese concentration which may indicate a toxic effect of excess manganese upon the liver.

Absorption↗
PubMed1976

Use of 1alpha-OH cholecalciferol in preventing post parturient hypocalcaemia and its potential value for the prevention of milk fever in dairy cows.

Cows which received 250 mug 1alpha-hydroxy cholecalciferol (1alpha-OH D3) intramuscularly within two hours after calving suffered significantly less post-parturinet hypocalcaemia and hypophosphataemia than control cows. There was a small depression in plasma magnesium concentrations in the treated cows. 1alpha-OH D3 shows potential for the prevention or treatment of milk fever.

Animals↗
PubMed1976

Manganese metabolism in cows and goats.

When 54MnCl2 was incubated with fresh bovine or caprine serum for 20 h and the serum subjected to electrophoresis at pH 9.5, the 54Mn bound to transferrin and alpha2-macroglobulin in proportions which varied with the temperature of incubation and the temperature of electrophoresis. Between 0 and 37 degrees C, the higher the temperature of incubation the larger the proportion bound to transferrin and the lower the proportion bound to alpha2-macroglobulin. The temperature at which electrophoresis was performed had little effect on the proportion of 54Mn bound to transferrin, but increasing temperature reduced the proportion of 54Mn bound to alpha2-macroglobulin. Mn2+ did not bind to purified transferrin in vitro in the absence of an oxidising agent. In the presence of permanganate, Mn3+ was formed and chelated by transferrin at physiological pH. In fresh serum this oxidation step may be performed by ceruloplasmin or molecular oxygen. Mn2+ was bound reversibly to alpha2-macroglobulin but this protein played no part in the oxidation of divalent manganese and had no effect on the protein binding of trivalent manganese. Manganese in the divalent state, either free as Mn2+ or bound to alpha2-macroglobulin, is removed from blood plasma very efficiently by the liver. However, the manganic-transferrin complex normally found in circulation is not rapidly removed from plasma. The liver can remove large amounts of excess manganous manganese which it presumably excretes; the small essential fraction of the manganese absorbed is oxidised to the trivalent state and bound to transferrin.

Animals↗
PubMed1976

Iron dynamics in the ruminant.

We have compared the plasma clearance rate of radioactive iron in cows both as ferric chloride and as iron specifically bound to transferrin. We have also repeated the transfusion experiment of Dern et al. (Dern, R.J., Monti A. and Glynn, M.F. (1963) J. Lab. Clin. Med. 61,280-291) using goats. The results show that neither non-specificity bound iron (Bates, F.W. and Schlabach, M.R. (1973) J. Biol. Chem. 248, 3228-3232) nor the iron bound to the two different sites in transferrin (Awai, M., Chipman, B. and Brown, E.B. (1975) J. Lab. Clin. Med. 85,769-784) can be identified as distinguishable iron pools by this technique.

Animals↗
PubMed1975

Some observations on the possible nutritional significance of vitamin B12-and folate-binding proteins in milk. Absorption of [58Co]cyanocobalamin by suckling piglets.

1. A study was made of absorption of [58Co]cyanocobalamin in suckling piglets. Cyanocobalamin given at birth and at 7 d of age was efficiently absorbed from the intestine and retained within the body, mostly in the liver. A 10 mug test dose was absorbed no less efficiently than 2-5 mug, despite the virtual absence of intrinsic factor in the gut. In piglets given a 10 mug test dose at different ages between 2-5 and 56 d, there was a marked decrease in the efficiency of retention between about 7 and 21 d of age. 2. Vitamin B12-binding capacity in the gastric muscosa increased with age, from 40 ng at birth to about 2000 ng at 14 d and 7000 ng at 35 d. This binder-protein was largely endogenous, whereas much of the unsaturated binder-protein in intestinal mucosa was apparently derived from milk. 3. The chyme in the stomach and small intestine contained unsaturated binder-protein, partly endogenous and partly deriving from milk, which prevented uptake of added [G-3H]-cyanocobalamin into the 'solids' phase of the intestinal contents. The intestinal chyme contained large numbers (log10 7-0--9-1/ml) of bacteria, some of which were isolated and shown to take up cyanocobalamin or folic acid or both. 4. The finings are discussed in relation to the concept that for some days or wekks after the cessation of transport of inact protein across the neonatal gut epithelium ('closure'), protein-bound vitamins may continue to be taken up into the epithelial cells and there released for transport into the circulation. It is concluded that unsaturated vitamin-binders may strongly influence the ecology of the intestinal microflora.

Animal Nutritional Physiological Phenomena↗