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DIET AND DIALYSIS
143 the proposals of Goldberg and Mitchell there may no longer be a clinical biochemist on the spot, but instead a specialist scientist; and thus the possibility of mutual discussion between the clinician and the biochemist responsible for producing the results of the routine investigations is lost. This will also lead inevitably to a great increase in the number of investigations requested as well as a decrease in understanding and interpretation of results. The increase in requests, the inevitable delay in receiving results which would lead to longer stays in hospital for patients, and the amount of time wasted on telephone calls all offset the so-called economies of the scheme. The basic error that Goldberg and Mitchell have made is to consider the production of biochemical results out of their clinical context. Economy expressed in determinations per pound sterling does not necessarily mean saving. They have also greatly underestimated the difficulties which geographical separation would introduce.
Hillingdon Hospital, Uxbridge, Middlesex.
A. H. JAMES R. M. BURTON J. A. MONRO W. H. A. PICTON C. M. HARPER.
of Medical Staff Committee
AMINOACID ABSORPTION IN PROTEIN MALNUTRITION SIR,-Protein malnutrition causes severe intestinal mucosal changes in human beings 1,2 and in rats,3varying from shortening of the villi to complete flattening of the In malnourished children, absorption of both mucosa. disaccharides and monosaccharides is reduced,5,6 but the effects of protein malnutrition on aminoacid absorption are not clear. 7,8 I have investigated the intestinal absorption of aminoacids in protein-depleted rats.
Pre-weanling rats were made protein-malnourished by the technique of Flores et al.. The biochemical findings in these rats closely resembled those in children with kwashiorkor. Controls were rats of the same age, fed a well-balanced diet. Intestinal absorption was measured by the in-situ loop technique.18 1 ml. of incubation medium consisting of Krebs’ bicarbonate-saline was injected into the loop, the saline containing in one case 10 VMOIC L-lysine plus 1 ILCi [14C] L-lysine (uniformly labelled) and in the other case 10 (µmole glycine plus 1 µCi [14C] glycine (uniformly labelled). These two aminoacids were chosen as representative of one essential and one non-essential aminoacid (for rats). 15 minutes were allowed for absorption, and the loop was then excised, washed through with distilled water, and made up to 100 ml. A 1 ml. sample of this was then taken for liquid scintillation counting. The difference between the number of counts injected and the number remaining in the intestine at the end of the 15 minutes was then taken as the absolute percentage absorption of the dose of aminoacid. The excised loop was then weighed, the mucosa scraped off with a glass slide, and the remaining tissue reweighed. The weight of the mucosa was then calculated. Absorption of the aminoacid was quantitated as the percentage dose absorbed per 500 mg. wet-weight mucosa. The results are shown in the accompanying table.
There was no difference between protein-depleted and control rats in the absorption of either L-lysine or glycine. The weight of mucosal scrapings from the protein-depleted intestine was only about half that for the same length of 1. Stanfield, J. P., Hutt, M. S., Tunnicliffe, R. Lancet, 1965, ii, 519. 2. Brunser, O., Reid, A., Monkeberg, F., Maccioni, A., Contreras, I. Pediatrics, Springfield, 1966, 38, 605. 3. Takano, J. Exp. molec. Path. 1964, 3, 224. 4. Hill, R. B., Prosper, J., Hirschfield, J. S., Kern, F. ibid. 1968, 8,
INTESTINAL ABSORPTION OF L-LYSINE AND GLYCINE FROM CONTROL AND PROTEIN-DEPLETED RATS IN VIVO*
Values
James, W. P. T. Lancet, 1968, i, 333. James, W. P. T. Clin. Sci. 1970, 39, 309. Adibi, S. Gastroenterology, 1970, 59, 404. Steiner, M., Grover, C., Farrish, M., Gray, S. J. Am. J. clin. Nutr. 1969, 22, 871. 9. Flores, H., Sierralta, W., Monkeberg, F. J. Nutr. 1970, 100, 375. 10. Steiner, M., Gray, S. J. Am .J. Physiol. 1969, 217, 747.
means ±s.E. of means, with number of
experiments in
control intestine, yet, judging by the percentage absorption per unit weight, there was no impairment of aminoacid absorption in the protein depleted animals. In addition, the fact that these two aminoacids are absorbed by two of the main transport systems for aminoacids in the intestine -i.e., the neutral and basic aminoacid systems-suggests that the transport of other aminoacids sharing these systems would be similarly unaffected by protein depletion. These results in rats agree with the work of Woodd-Walker et aI.,l1 who showed no impairment of aminoacid absorption by small intestine in malnourished children. In contrast are the effects of semi-starvation 12,13 and complete starvation 10 in rats. In these states of dietary deprivation, aminoacid absorption is considerably enhanced in vitro and in vivo. The adaptive metabolic responses which come into operation during protein depletion and fasting are, however, very different,14,15 so it is not surprising that aminoacid absorption is also different. These findings lend support to work in human beings showing that even in severe protein malnutrition resulting in severe intestinal mucosal damage aminoacid absorption mechanisms remain undamaged. Tropical Metabolism Research Unit, University of the West Indies, Kingston 7, Jamaica, West Indies.
R.
J. NEALE.
DIET AND DIALYSIS 16
you express the hope that patients afford the cost of the ingredients in some of the recipes in Good Food and the Artificial Kidney. For some time, dietitians working in renal units have been concerned about the high cost of the diet. We periodically inform the Department of Health and Social Security of this (it was about E4 a week in December, 1970), so that, in cases of need, a supplementary benefit above the amount normally allowed for special diets can be given. (Most special diets need not cost more than the normal diet.) May we emphasise that many of the ingredients which would normally be considered luxuries are essentials in such a controlled regimen where, in most cases, a high calorie intake and a high degree of palatability are of the utmost importance. E. O. ELLIS B. MACARTNEY British Dietetic Association, H. GARDINER. London S.W.3. Organisers, Renal Dialysis Group.
SIR,-In
your note
can
*** The price of Department, Royal
the booklet, obtainable from the Dietetic Free Hospital, North Western Branch, London N.W.3, is 5s., plus 3s. postage (not 3d. postage as given in our note).-ED. L. 11.
Woodd-Walker, R. B., Hansen, J. D. L., Saunders, S. J. Lancet, 1969, ii, 1428.
66.
5. 6. 7. 8.
are
parentheses.
Kershaw, T. G., Neame, K. D., Wiseman, G. J. Physiol., Lond. 1960, 152, 182. 13. Neale, R. J., Wiseman, G. ibid. 1969, 205, 159. 14. Schimke, R. T. J. biol. Chem. 1962, 237, 196. 15. Viteri, F., Behar, M., Arroyave, G., Scrimshaw, N. S. in Mammalian Protein Metabolism; voL II. New York, 1964. 16. Lancet, 1970, ii, 1371. 12.
Hillingdon Hospital, Uxbridge, Middlesex.
A. H. JAMES R. M. BURTON J. A. MONRO W. H. A. PICTON C. M. HARPER.
of Medical Staff Committee
AMINOACID ABSORPTION IN PROTEIN MALNUTRITION SIR,-Protein malnutrition causes severe intestinal mucosal changes in human beings 1,2 and in rats,3varying from shortening of the villi to complete flattening of the In malnourished children, absorption of both mucosa. disaccharides and monosaccharides is reduced,5,6 but the effects of protein malnutrition on aminoacid absorption are not clear. 7,8 I have investigated the intestinal absorption of aminoacids in protein-depleted rats.
Pre-weanling rats were made protein-malnourished by the technique of Flores et al.. The biochemical findings in these rats closely resembled those in children with kwashiorkor. Controls were rats of the same age, fed a well-balanced diet. Intestinal absorption was measured by the in-situ loop technique.18 1 ml. of incubation medium consisting of Krebs’ bicarbonate-saline was injected into the loop, the saline containing in one case 10 VMOIC L-lysine plus 1 ILCi [14C] L-lysine (uniformly labelled) and in the other case 10 (µmole glycine plus 1 µCi [14C] glycine (uniformly labelled). These two aminoacids were chosen as representative of one essential and one non-essential aminoacid (for rats). 15 minutes were allowed for absorption, and the loop was then excised, washed through with distilled water, and made up to 100 ml. A 1 ml. sample of this was then taken for liquid scintillation counting. The difference between the number of counts injected and the number remaining in the intestine at the end of the 15 minutes was then taken as the absolute percentage absorption of the dose of aminoacid. The excised loop was then weighed, the mucosa scraped off with a glass slide, and the remaining tissue reweighed. The weight of the mucosa was then calculated. Absorption of the aminoacid was quantitated as the percentage dose absorbed per 500 mg. wet-weight mucosa. The results are shown in the accompanying table.
There was no difference between protein-depleted and control rats in the absorption of either L-lysine or glycine. The weight of mucosal scrapings from the protein-depleted intestine was only about half that for the same length of 1. Stanfield, J. P., Hutt, M. S., Tunnicliffe, R. Lancet, 1965, ii, 519. 2. Brunser, O., Reid, A., Monkeberg, F., Maccioni, A., Contreras, I. Pediatrics, Springfield, 1966, 38, 605. 3. Takano, J. Exp. molec. Path. 1964, 3, 224. 4. Hill, R. B., Prosper, J., Hirschfield, J. S., Kern, F. ibid. 1968, 8,
INTESTINAL ABSORPTION OF L-LYSINE AND GLYCINE FROM CONTROL AND PROTEIN-DEPLETED RATS IN VIVO*
Values
James, W. P. T. Lancet, 1968, i, 333. James, W. P. T. Clin. Sci. 1970, 39, 309. Adibi, S. Gastroenterology, 1970, 59, 404. Steiner, M., Grover, C., Farrish, M., Gray, S. J. Am. J. clin. Nutr. 1969, 22, 871. 9. Flores, H., Sierralta, W., Monkeberg, F. J. Nutr. 1970, 100, 375. 10. Steiner, M., Gray, S. J. Am .J. Physiol. 1969, 217, 747.
means ±s.E. of means, with number of
experiments in
control intestine, yet, judging by the percentage absorption per unit weight, there was no impairment of aminoacid absorption in the protein depleted animals. In addition, the fact that these two aminoacids are absorbed by two of the main transport systems for aminoacids in the intestine -i.e., the neutral and basic aminoacid systems-suggests that the transport of other aminoacids sharing these systems would be similarly unaffected by protein depletion. These results in rats agree with the work of Woodd-Walker et aI.,l1 who showed no impairment of aminoacid absorption by small intestine in malnourished children. In contrast are the effects of semi-starvation 12,13 and complete starvation 10 in rats. In these states of dietary deprivation, aminoacid absorption is considerably enhanced in vitro and in vivo. The adaptive metabolic responses which come into operation during protein depletion and fasting are, however, very different,14,15 so it is not surprising that aminoacid absorption is also different. These findings lend support to work in human beings showing that even in severe protein malnutrition resulting in severe intestinal mucosal damage aminoacid absorption mechanisms remain undamaged. Tropical Metabolism Research Unit, University of the West Indies, Kingston 7, Jamaica, West Indies.
R.
J. NEALE.
DIET AND DIALYSIS 16
you express the hope that patients afford the cost of the ingredients in some of the recipes in Good Food and the Artificial Kidney. For some time, dietitians working in renal units have been concerned about the high cost of the diet. We periodically inform the Department of Health and Social Security of this (it was about E4 a week in December, 1970), so that, in cases of need, a supplementary benefit above the amount normally allowed for special diets can be given. (Most special diets need not cost more than the normal diet.) May we emphasise that many of the ingredients which would normally be considered luxuries are essentials in such a controlled regimen where, in most cases, a high calorie intake and a high degree of palatability are of the utmost importance. E. O. ELLIS B. MACARTNEY British Dietetic Association, H. GARDINER. London S.W.3. Organisers, Renal Dialysis Group.
SIR,-In
your note
can
*** The price of Department, Royal
the booklet, obtainable from the Dietetic Free Hospital, North Western Branch, London N.W.3, is 5s., plus 3s. postage (not 3d. postage as given in our note).-ED. L. 11.
Woodd-Walker, R. B., Hansen, J. D. L., Saunders, S. J. Lancet, 1969, ii, 1428.
66.
5. 6. 7. 8.
are
parentheses.
Kershaw, T. G., Neame, K. D., Wiseman, G. J. Physiol., Lond. 1960, 152, 182. 13. Neale, R. J., Wiseman, G. ibid. 1969, 205, 159. 14. Schimke, R. T. J. biol. Chem. 1962, 237, 196. 15. Viteri, F., Behar, M., Arroyave, G., Scrimshaw, N. S. in Mammalian Protein Metabolism; voL II. New York, 1964. 16. Lancet, 1970, ii, 1371. 12.