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Showing papers on "Low protein published in 1972"


Journal ArticleDOI
TL;DR: It is concluded that the non-histone proteins which remain tightly bound to DNA in chromatin are of the same approximate size as the basic histones.

191 citations


Journal ArticleDOI
TL;DR: The hypothesis that puberty occurs at a critical body weight was not supported and that social stimulation was more effective than protein intake may have relevance to the phenomenon of accelerated sexual maturation in human females.
Abstract: At 21 days of age, 144 female albino mice were individually isolated and reared on either 8% 16% or 24% protein diets. Within each protein level, mice were exposed to the presence of an adult male, or to male odour, or were reared in isolation. Each female was examined daily for vaginal opening and signs of first oestrus. Body weight and food consumption measures confirmed that body growth was equal in each cell of the design and that mice on low protein diets were not compensating for a low protein diet by consuming more food. The results showed that, although both dietary protein and the presence of males (or their odour) were significant factors in regulating sexual maturation, social factors contributed 47\m=.\3%and dietary protein levels 4\m=.\8%of the total variance. Accelerated sexual development was not accompanied by accelerated body growth. Thus, the hypothesis that puberty occurs at a critical body weight was not supported by these data. That social stimulation was more effective than protein intake may have relevance to the phenomenon of accelerated sexual maturation in human females.

148 citations


Journal ArticleDOI
01 Jun 1972
TL;DR: In this paper, the association behavior of αs1- and β-casein was investigated by light scattering at normal and elevated pressures, and it was inferred that hydrophobic bonding is the main driving force in the association of the caseins.
Abstract: The associations of αs1- and β-casein were investigated by light scattering at normal and elevated pressures. Special care was taken to measure the concentration dependence of the apparent molecular weight at very low protein concentrations. The association behavior of both proteins appeared to be quite different. αs1-Casein undergoes a series of consecutive association steps, whereas β-casein forms polymers of a very high degree of polymerization. Two methods have been proposed for the separation of the contributions of association and nonideality to the apparent molecular weight and values of the association constants and second virial| coefficients are presented for both proteins. From thermodynamic considerations it was inferred that hydrophobic bonding is the main driving force in the association of the caseins. This is in agreement with the results of light-scattering measurements at elevated pressures which show the polymers to be dissociated with increasing pressure up to 1500 kg/cm2.

91 citations


Journal ArticleDOI
TL;DR: It is suggested that the diminution of enzyme velocities for the low protein group is related both to a lower DNA content per gram tissue and to a loss of specific enzymic activity per milligram microsomal protein.
Abstract: The effect of protein deficiency in male weanling rats on the activity of the hepatic microsomal enzyme system was studied. Animals were divided into three groups and were fed for 15 days either a semipurified diet con taining 5% casein (group 1), 20% casein pair-fed to the 5% casein group (group 2) or 20% casein fed ad libitum (group 3). The liver weight, as a per centage of body weight, was higher in group 1. For group 1 animals, microsomal protein and DNA, when expressed per gram of liver, were approximately one-half the contents of groups 2 and 3. Maximal velocities for ethylmorphine (EM) and aniline (AN) were lower in group 1, whether these rates are expressed per milli gram microsomal protein, per gram liver or per 100 g body weight. A comparison of these methods of expression suggested that the diminution of enzyme velocities for the low protein group is related both to a lower DNA content per gram tissue and to a loss of specific enzymic activity per milligram microsomal protein. The Kmfor ethylmorphine was lower and that for aniline was higher in group 1 ani mals. Restriction of food intake affected enzyme kinetic parameters similar to protein deficiency but to a significantly lesser degree. Alternative explanations for this effect of protein deficiency are discussed and an involvement of phospho- lipid is suggested. J. Nutr. 102: 53-60, 1972.

73 citations


Journal ArticleDOI
TL;DR: It was concluded that changes in lamb composition could be interpreted according to classical studies on the influence of undernutrition on the relative growth and development of animal tissues.
Abstract: The effects of low protein and low Ca intakes during pregnancy on lamb composition and mineral contents have been investigated. Twenty-eight 6½-year-old Blackface ewes were used in a 2 × 2 experiment in which semi-purified diets containing 11·8 and 6·0% crude protein and 1·2 and 0·11 % Ca in the dry matter were offered to maintain constant levels of non-esterified fatty acids (NEFA) and ketone bodies in the plasma, comparable to those found in hill sheep in winter. A further group, control, were fed a conventional diet containing adequate crude protein and Ca to maintain NEFA and ketone body levels typical of well-nourished sheep. The lambs were killed at birth and whole body fat, moisture, nitrogen, Ca, P, Mg, Na and K contents determined. Further data was obtained on the brain, liver and semitendinosus muscle. Within the context of the experiment the most important factor in determining the mineral content of the lambs was the protein intake of the ewe, mainly due to its effect on lamb body weight. The mean Ca content of lambs from the control ewes was 47·8 g. By comparison that of lambs from the high and low protein groups was reduced by 4·9 and 12·9 g respectively. Calcium intakes as low as 27 mg/kg ewe body weight/day had no significant effect on lamb birth weight or mineral composition. The mean concentrations (g/kg) of minerals in the fat-free bodies of the lambs ranged from 12·1 to 14·6 for Ca, 6·6 to 7·4 for P, 0·49 to 006 for Mg and from 1·9 to 1·6 for K in the control and double deficiency groups respectively. It was concluded that these changes in lamb composition could be interpreted according to classical studies on the influence of undernutrition on the relative growth and development of animal tissues. The livers of the lambs, although significantly reduced in weight by the protein deficiency showed no evidence of being relatively more severely affected than muscle tissue.

58 citations


Journal ArticleDOI
TL;DR: Preliminary evidence that dietary intake can profoundly influence the development of autoimmune disease is taken to suggest that further systematic studies must be carried out to dissect more specifically the nature of these dietary influences.
Abstract: SummaryNZB mice are extensively used throughout the world as a model system for studying autoimmune disease. Apparently associated with a propensity to early development of autoimmune hemolytic anemia, the breeding capacity of NZB mice is defective; and the life span of these animals is short. As part of a general effort to improve breeding in our colonies, comparison of the influence of two commercial diets on NZB mice was made. One diet provided low protein and relatively high fat; the other, somewhat higher protein and lower fat content. Improved breeding performance was observed in the animals fed higher fat, lower protein intake. But, this diet influenced the animals adversely by fostering development of hemolytic anemia and shortening the life span both in males and females; whereas higher protein and lower fat extended particularly the longevity of male mice. These observations are taken as preliminary evidence that dietary intake can profoundly influence the development of autoimmune disease and t...

51 citations


Journal ArticleDOI
TL;DR: Independent of birth weight or maturity, infants with cord protein determinations above 4.6 g per 100 ml demonstrated a favorable prognosis, with an incidence of respiratory-distress syndrome of less than 0.5 per cent.
Abstract: Umbilical-cord blood total protein determinations were performed on specimens from 2200 infants delivered over an eight-month period with the use of a rapid, convenient, and reproducible TS-meter protein measurement. In 34 infants the idiopathic respiratory-distress syndrome developed; 33 of the 34 had a cord-blood total protein concentration of 4.6 g per 100 ml or less. One third of the neonates with protein values at or below this level were affected by the syndrome, as were 1/2 of the immature or low-birth-weight infants with low protein levels. Independent of birth weight or maturity, infants with cord protein determinations above 4.6 g per 100 ml demonstrated a favorable prognosis, with an incidence of respiratory-distress syndrome of less than 0.5 per cent.

50 citations


Journal ArticleDOI
TL;DR: Samples of the colloid in rat thyroid follicles were obtained by micropuncture of superficial and deeper follicles in saline perfused thyroids and the protein compositions of the samples were analyzed by microgel electrophoresis.
Abstract: Samples of the colloid in rat thyroid follicles were obtained by micropuncture of superficial isthmic follicles in vivo and of superficial and deeper follicles in saline perfused thyroids. The protein compositions of the samples were analyzed by microgel electrophoresis. The amount of protein in the different fractions in the colloid samples was determined by microdensitometry. The sample volumes were estimated by measuring the amount of radioactivity in a solution occupying the same space in the tip of the collecting pipette as the colloid sample. Samples of colloid containing 19S thyroglobulin (TG) and proteins migrating more slowly than 19S TG had low protein concentrations, about 5 g/100 ml. Samples containing a prealbumin fraction in addition to the large proteins in the previous group had significantly higher protein concentrations, about IS g/100 ml. Colloid samples containing additional proteins (an albumin- like protein and a globulin) generally had mean protein concentrations around 10 g/100 ml....

49 citations


Journal ArticleDOI
TL;DR: The growth rate of calves fed soy replacers only from 7 to 10 days of age was approximately 20% less than that of the calves fed all-milk replacers, and blood urea indicated a better utilization of the absorbed soy protein when concentrates were consumed by the calves.

43 citations


Journal ArticleDOI
TL;DR: The EPR spectrum of AzoFd and that of the combination of the two nitrogenase components undergoes characteristic changes upon addition of MgATP2− as mentioned in this paper.

41 citations


Book ChapterDOI
TL;DR: The chapter considers only the choline-containing lipids, but in almost all cases a fairly complete analysis of the different phospholipid types has been carried out, and this may be obtained by consulting the appropriate reference.
Abstract: Publisher Summary The importance of choline in the metabolic processes of vertebrates has been established for many years. Nutritional studies with animals fed on low protein and high fat regimes have demonstrated that large amounts of choline are required in the diet if normal growth is to be maintained and fatty infiltration of the liver prevented. In insects, various aspects of choline metabolism have been looked at in differing detail. The cholinergic system has received a great deal of attention because of its importance in relation to the mode of action of organophosphorus and carbamate insecticides. The composition of insect phospholipids has been analyzed and results from a large number of species have accumulated over the past few years. The chapter considers only the choline-containing lipids, but in almost all cases a fairly complete analysis of the different phospholipid types has been carried out, and this may be obtained by consulting the appropriate reference. A number of studies have been made following the change of phospholipid pattern during development, but little has been achieved in understanding the metabolic role of the phospholipid.

Journal ArticleDOI
TL;DR: Cubed diets have been produced with protein values of 6.8 and 10 net dietary protein-calories per cent that will enable workers to test for possible adaptations in the physical and mental development of rats and dogs over many generations.
Abstract: Cubed diets have been produced with protein values of 6.8 and 10 net dietary protein-calories per cent. Both diets support reproduction over several generations but the colony maintained on the diet of low protein value has low birth weights, slow rates of growth and small adult size. It is suggested that these diets will enable workers to test for possible adaptations in the physical and mental development of rats and dogs over many generations.


Journal ArticleDOI
TL;DR: In this paper, two complete energy balance trials were performed with lactating and dry cows consuming 40% of the dry matter from concentrate and 60% from corn silage, and two concentrate mixtures were given so that the total diets contained 16.0 and 11.2% crude protein.

Journal ArticleDOI
TL;DR: Wheat seedlings grown from seeds of different protein levels, obtained from an N fertilizer field trial, showed significant differences in dry matter and a high positive correlation (r = 0.920**) between seed protein content and dry matter after 3 weeks’ growth.
Abstract: Wheat seedlings grown from seeds of different protein levels, obtained from an N fertilizer field trial, showed significant differences in dry matter and a high positive correlation (r = 0.920**) between seed protein content and dry matter after 3 weeks’ growth. In further studies using low and high protein seeds (99 and 142 mg/g), dry matter differences were obtained at up to 40 days from sowing and in different temperature and light intensity environments with nutrient concentrations containing up to 24 mM nitrate. Maximum dry matter accumulation occurred at approximately 5 mM nitrate but no limit was reached in protein accumulation with up to 24 mM nitrate. Seedlings grown from high protein seeds were shown to be more advanced in morphological development than those seedlings grown from low protein seeds.

Journal ArticleDOI
TL;DR: Although sulfonamides as a group are thought to be effective displacers of bilirubin, sulfanilamide and sulfadiazine were not found to cause much displacement, probably because of their low protein binding.
Abstract: Several antimicrobial agents and sodium salicylate were tested for their ability to displace bilirubin from albumin by measuring the increase in bilirubin binding by erythrocytes caused by these drugs in vitro. The ability of the drugs to cause bilirubin displacement seemed to be related to the degree of protein binding of the different drugs, so that substances known to be protein bound to more than 50–60% are potential displacers of bilirubin. Although sulfonamides as a group are thought to be effective displacers of bilirubin, sulfanilamide and sulfadiazine were not found to cause much displacement, probably because of their low protein binding. Most effective displacers were novobiocin, cloxacillin, sulfisoxazole, and salicylate, all known to be almost entirely protein bound. Lowering of the pH level greatly potentiated the displacing effect found.

Journal ArticleDOI
TL;DR: The mild preparative methods employed in obtaining whole casein by centrifugation at pH 6.6 probably yield complexes more representative of their native quarternary structure than the casein complexes discussed previously, which support a model of the native casein micelle built up from a 100-A-diameter complex containing all the case in fractions.

Journal ArticleDOI
TL;DR: Renaturation was attempted from both denaturants, the removal of reagent being accomplished reversibly by controlled slow dialysis, but partial renaturation was observed, but aggregated or insoluble material was produced in both cases at relatively low concentrations of denaturant.
Abstract: 1. The denaturation of ovalbumin by the reagents sodium dodecyl sulphate and guanidinium chloride was investigated, by following the changes in sedimentation velocity, optical rotatory dispersion and viscosity as a function of denaturant concentration. 2. With sodium dodecyl sulphate both the optical-rotatory-dispersion parameters a(0) and b(0) become more negative, the sedimentation coefficient decreases and the viscosity increases; significant differences in the denaturation profiles are observed. The change in each parameter is indicative of only limited denaturation. 3. With guanidinium chloride the transition occurs over the concentration range 1-4m: more extensive changes occur in all the physical parameters than with sodium dodecyl sulphate. The values of a(0) and b(0) are indicative of complete denaturation. Reduction by mercaptoethanol produces only minor further changes. 4. Renaturation was attempted from both denaturants, the removal of reagent being accomplished reversibly by controlled slow dialysis. Partial renaturation was observed, but aggregated or insoluble material was produced in both cases at relatively low concentrations of denaturant. Similar behaviour was observed with fully reduced protein in guanidinium chloride-mercaptoethanol; complete renaturation could not be brought about even at very low protein concentrations.

Journal ArticleDOI
TL;DR: The accumulation of NADH and lipids in the liver tissue is also significantly lowered following treatment of the intoxicated rats with (+)-cateehin, and the biochemical mechanism of these effects is discussed.

Journal ArticleDOI
TL;DR: The observations are consistent with the view that changes in capillary hydrostatic pressure produced by the different perfusion rates played a role in the changes in sodium and water reabsorption under these experimental conditions.

Journal ArticleDOI
TL;DR: The full range of urea tolerance is present before birth, although required mechanisms may be present, and independent osmoregulation apparently does not occur before birth.

Journal ArticleDOI
TL;DR: The 128-fold purified enzyme exhibits a specific activity of 106 units/mg of protein and was adjudged to be homogeneous by rechromatography, sedimentation velocity and sedimentation equilibrium ultracentrifugation, and a variety of electrophoretic techniques.
Abstract: 1. A procedure for the purification of lactate dehydrogenase (E.C. 1.1.1.27) from the tapeworm,Hymenolepis diminuta, is described. 2. The 128-fold purified enzyme exhibits a specific activity of 106 units/mg of protein and was adjudged to be homogeneous by rechromatography, sedimentation velocity and sedimentation equilibrium ultracentrifugation, and a variety of electrophoretic techniques. 3. Only one form of the enzyme is present in the tapeworm as demonstrated by electrophoresis on cellulose acetate, polyacrylamide-gel and isoelectric focusing. 4. The molecular weight of the native enzyme is 141,000 and exhibits a sedimentation coefficient of 6·89 × 10-13 sec. The enzyme is a tetramer composed of subunits of molecular weight 36,000. However, under low protein concentrations (0·1 mg/ml) on analytical gel filtration, the enzyme dissociates to the dimeric state and exhibits a molecular weight of 75,000. 5. Inhibitor studies are consistent with an active center which may be catalytically and structurally similar to the enzyme from vertebrates. 6. The enzyme is kinetically similar to vertebrate heart LDH. The Km for pyruvate was 0·17 mM and for lactate was 6·3 mM. TheH. diminuta lactate dehydrogenase also forms an abortive ternary complex with coenzyme and substrate. 7. The data are discussed in regard to the physiology of the parasite and the host.

Dissertation
01 Jan 1972
TL;DR: The relationship between the whiteback vulture Gyps africanus, and Ruppell's griffon Gyps ruppellii and their food supply was studied in the Serengeti National Park in northern Tanzania for sixteen months during 1969 and 1970.
Abstract: The relationship between the whiteback vulture Gyps africanus, and Ruppell's griffon Gyps ruppellii and their food supply was studied in the Serengeti National Park in northern Tanzania for sixteen months during 1969 and 1970. Seven species of vulture occur in this region, although over most of their ranges each species is separated from the others ecologically and they do not compete. These two griffon vultures both specialise in taking the soft parts of carcasses and between them account for 85% of all vulture sightings in this area. In the Serengeti region both species are common, an unusual situation, and they are potentially in direct competition for the same food supply. In the Serengeti about 80% of herbivores are migratory and the large distances covered by these herds during the year prevents their predators from increasing sufficiently to become a major mortality factor. Other causes of mortality are therefore of far greater importance arid may account for perhaps 80% of all mortality in the area. However, the nature of this mortality causes seasonal fluctuations in the number of deaths, as well as the variations in distribution caused by the movements of the herds. These conditions prevent mammalian scavengers from being able to utilise the food effectively, and these may take perhaps only 5% of the total food available to scavengers. There is therefore potentially available a food supply for scavengers which fluctuates considerably in quantity and distribution through the year. This is the food supply that griffon vultures utilise. Predators are usually efficient in their feeding and vultures obtain only small amounts of food from predator kills. A large vulture population can probably only occur in areas where there is a food supply that is not effectively exploited by mammalian carnivores. In the Serengeti there are probably two peaks of food availability. At the end of the dry season when animals are in poorest condition and scattered widely through the northern woodlands, and a second peak at the time of wildebeest calving when herds are heavily concentrated on the eastern plains. Birds travel widely during food searching and tend to concentrate heavily in areas of large game herds, which is where most of the food is available. The Ruppell's griffon is uncommon in areas away from the migratory herds. They locate food largely by watching the activity of other birds and converging on an area where vultures are seen to be descending. In areas of moderate game density birds search at low altitudes and relatively high density so that birds congregate rapidly at any food source. However, in areas with little game, birds search at higher altitudes and may not always be within sight of other individuals, and fewer birds may be attracted to carcasses. Since birds can cover large distances rapidly, they are able to exploit the food supply despite variations in distribution through the year. However, food also fluctuates in abundance. Captive birds were used to establish the food requirements for inactive birds. The amount of food actually obtained by wild birds was also recorded from the size of the crop of birds roosting in the afternoon, and this showed that non breeding birds during the first half of 1970 were probably able to obtain sufficient food to satisfy their food requirements. Their fat levels were high throughout this period. Birds can store fat very rapidly after a large food intake and use this to last over periods when the food supply is not adequate to satisfy the food requirements. The body temperature does not fall abnormally at night. The food requirements of birds could be increased seasonally by both moult and breeding. Moult is continuous throughout the birds life. Primary feather moult starts about ten months after the bird leaves the nest, and the first feather to be shed is the innermost primary. From this position primary moult proceeds in an orderly progression outwards towards the tip of the wing. Subsequent primary moults also occur as similar waves of moult activity moving outwards across the wing. Secondary moult, however, does not show a clear pattern. The innermost secondary is the first to develop, but later feather replacements occur at sites further along the wing, and although there is no fixed position for these additional growing sites, there is a tendency for replacement to occur first in three areas. Further secondary replacement does not occur by the progression of moult waves, but by the irregular growth of feathers. Subsequent secondary moults also appear to be irregular. It probably takes about three years of moult activity to complete the first feather replacement. Adult birds show individual variation in the number of actively growing feathers, but this could not be related to breeding or body condition. Feather growth accounts for perhaps 6% of the total energy intake of the bird throughout the year. Breeding, however, is confined to a definite season. The Ruppell's griffon lays about two to three months earlier than the whiteback. In the Ruppell's griffon the food requirements for egg laying are considered to be slight, although the provision of calcium for the egg shell might be an important factor. Captive chicks were hand reared to determine their food requirements during growth and these estimates were combined with the figure for the food requirements of adult birds to determine a total estimate of food requirements for breeding birds. The amount of food actually obtained by a group of birds was recorded from the size of the crops of birds returning to the colony in the afternoon. The comparison of food obtained and food required through the season suggested that their may be a period during rearing when there was insufficient food available to satisfy the food requirements of both chick and adult. Chicks were found to have a very high survival rate and they are not able to alter their growth rate according to the amount of food that they are supplied and presumably chick food requirements were being met. The examination of a sample of adult birds for body condition through the year showed a clear decline in the fat deposits through the breeding season, although no bird was found with seriously low protein levels. It was considered that for both species breeding is timed so that the young leave the nest at a period in the year when food conditions are good and young birds can feed with little competition from adults. However, adults have to rear young during a period in the year when food conditions are not always adequate and they have to rely on utilising fat reserves.

Journal ArticleDOI
TL;DR: Changes observed in the composition and flow of digesta and in plasma urea and cc-amino nitrogen levels are discussed in relation to the digestion of organic matter and protein.
Abstract: The effect of formaldehyde treatment of peanut meal on the digestion of barley-peanut meal diets was studied in fistulated crossbred sheep at two peanut meal and therefore dietary protein levels There were no differences either between protein levels or due to treatment in the overall digestion of organic matter, but more of this digestion took place in the stomach when the low protein diets were given Dietary starch was completely digested There was no effect of protein level or of formaldehyde treatment on the partition of starch digestion between the stomach and the intestines About 10% of the dietary nitrogen disappeared from the stomach when the high protein diet containing untreated peanut meal was given; treatment resulted in a small net gain of nitrogen in the stomach There was a net gain of nitrogen in the stomach when the low protein diets were given, the gain tending to be greater when the peanut meal was treated When the meal was treated, there was a small but not significant increase (c 2%) for the low protein diet and a substantial increase (c 31 %) for the high protein diet in the amount of crude protein digested in the intestines per unit of digestible organic matter intake Changes observed in the composition and flow of digesta and in plasma urea and cc-amino nitrogen levels are discussed in relation to the digestion of organic matter and protein

Journal ArticleDOI
TL;DR: It is obvious from these data that increased reproductive efficiency results from nutrient restriction of toms during the growing period.


Journal ArticleDOI
TL;DR: Three experiments were carried out using male broiler chicks from 1 to 3 weeks of age and found that housed in individual metabolism cages at 1 week of age, having previously been in tiered brooders, proved to be successful in rearing male broilers.
Abstract: Synopsis Three experiments were carried out using male broiler chicks from 1 to 3 weeks of age. The birds were housed in individual metabolism cages at 1 week of age, having previously been in tiered brooders. In experiment 1, 36 birds were offered one of six experimental diets based on glucose‐ and cellulose‐diluted commercial broiler mash. The six diets were supplemented with graded levels of triammonium citrate (TAC) at the expense of cellulose such that diet 1B contained no TAC and diet 1F contained 6.4% TAC. In experiment 2, 72 birds were offered one of six diets, similar to those used in experiment 1 with the exception that they were supplemented with graded levels of diammonium hydrogen citrate (DAHC). In experiment 3, 72 birds were offered one of six diets which were based on the same diluted broiler mash but which had been supplemented with graded levels of autoclaved dried poultry manure (ADPM) at the expense of glucose. Diet 3B contained no ADPM whereas diet 3F contained 20% ADPM. All birds wer...

Book ChapterDOI
E. Mehl1
TL;DR: Within the group of plasma membranes, isolated and studied until now, the myelin membrane has a typical characteristically low protein content of 20 percent and a protein composition of reduced complexity and by work on isolated cerebral myelin, the encephalitogenic basic protein was directly shown to be a myelin protein.
Abstract: Within the group of plasma membranes, isolated and studied until now, the myelin membrane has a typical characteristically low protein content of 20 percent (3,15,18) and a protein composition of reduced complexity. By work on isolated cerebral myelin, the encephalitogenic basic protein was directly shown to be a myelin protein (17, 18). Autilio (2) applied gel filtration in chloroformmethanol and obtained a further myelin protein fraction comprising 55 to 65 percent of total myelin proteins. This protein fraction had an amino acid composition almost identical to the classical Folch-Lees proteolipid protein (13) which was extracted from cerebral white matter and subjected to a purification step.

Journal ArticleDOI
TL;DR: The data presented lead to the conjecture that inborn errors of ammonia detoxification which result in clinical disease in surviving patients are “partial” defects, and that “complete’ defects in ammonia detoxifying are so rapidly lethal as to be seldom recognized clinically.
Abstract: Extract: The excretion of 15N in the urine following the oral administration of compounds labeled with 15N was evaluated in an infant with congenital hyperammonemia while the infant was receiving a low protein diet. When she received either 15N-glycine or 15NH4Cl, the ratio of [15N-NH3] to [15N-urea] in urine was strikingly elevated with respect to [15N-NH3]/[15N-urea] found in studies of other infants receiving high protein diets. However, reduction of the protein in the diet of the control infants resulted in elevation of the ratio of [15N-NH3] to [15N-urea] in urine after the administration of 15N-glycine or 15NH4Cl. No mode of metabolism specific for congenital hyperammonemia was demonstrated in the studies of orally administered 15NH4Cl. In the metabolism of 15N-glycine, the hyperammonemic infant receiving a low protein diet was different from other infants on both high and low protein diets. In the hyperammonemic infant, 15N-urea was much more readily formed from 15N-citrulline than from 15NH4Cl. On the other hand, the addition of unlabeled citrulline to the diet of this infant did not enhance the synthesis of 15N-urea from ingested 15NH4Cl when compared with the addition of unlabeled ornithine-HCl to the diet. Speculation: The data presented lead to the conjecture that inborn errors of ammonia detoxification which result in clinical disease in surviving patients are “partial” defects, and that “complete” defects in ammonia detoxification are so rapidly lethal as to be seldom recognized clinically.

Journal ArticleDOI
TL;DR: Feed consumption and body weights were the greatest in the control group, followed by the skip-a-day group, with the low protein group consuming the least feed and having the lightest body weights.