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Biomedical subjects

W C MacLean

Publications and source records attributed to W C MacLean.

68 records · Page 4Linked to original sources
PubMed1978

Transient steatorrhea following episodes of mild diarrhea in early infancy.

Fecal fat excretion was studied after a mild episode of diarrhea in eight infants for whom adequate control data were available. Mean age of onset of diarrhea was 28 days. Duration of the episode, defined as the number of days until the infant was again feeding and libitum, averaged 5.1 days. Balance studies were carried out 3 to 13 days later. Mean fecal fat excretion rose from a prediarrhea value of 2.9 +/- 1.4 gm/day to 8.7 +/- 3.1 gm/day following diarrhea (P less than 0.001). Restudy of five infants one month later showed persistent steatorrhea in one. Mild transient steatorrhea may follow mild diarrhea in infancy and should be considered in infants who are slow to gain weight subsequent to an episode of diarrhea.

Animals↗
PubMed1978

Oral iron absorption in infantile protein-energy malnutrition.

The ability of infants with protein-energy malnutrition to absorb iron was assessed using the serum iron response to a dose of ferrous sulfate providing 3 mg elemental iron per kg body weight. Responses were grouped as flat (delta serum Fe less than 30 microgram/dl), intermediate (30 to 100 microgram/dl), and normal (greater the 100 microgram/dl). Of 25 consecutively admitted children studied, seven had a flat, five an intermediate, and 13 a normal curve (mean delta serum Fe: 10 microgram/dl, 66 microgram/dl, and 175 microgram/dl, respectively). There were no differences among the three groups in hematocrit, fasting serum iron or transferrin saturation, severity of malnutrition, or evidence of other malabsorption sufficient to explain these differences. Although hematocrits, fasting serum iron, and transferrin saturations did not change appreciably during nutritional rehabilitation, all children with initially abnormal responses subsequently had normal tests.

Absorption↗
PubMed1978

Fasting plasma free amino acids of infants and children consuming cow milk proteins.

We have analyzed the fasting plasma aminograms of 165 infants and small children. Mean age was 17 months (range, 3-42 months). The majority had been consuming a diet in which all protein was supplied by calcium caseinate, the remainder a modified cow milk formula. Protein provided less than 6.4% of energy for 8 children, 6.4%-7% of energy for 81 children, 8% of energy for 42 children and greater than 8% of energy for 34. Only the values for the concentrations of total essential amino acids, valine, and taurine at less than 6.4% of energy as protein were significantly lower than corresponding values at higher intakes of protein. Analysis of the remainder of the data revealed no significant differences in either absolute concentrations or molar fractions among differing levels or sources of protein intake. Interindividual variation in concentrations of amino acids was greater than that resulting from changes in the level of intake of high quality protein when 6.4% or more of energy was provided as protein.

Amino Acids↗
PubMed1977

Wheat-based diets: effect of short-term consumption on serum cholesterol and triglyceride levels in infants.

The effect of consumption of wheat-based diets on serum cholesterol and triglyceride levels was studied in eight previously malnourished children. While consuming a control diet of casein, soy-cottonseed oil blend, and a mixture of sucrose and starch, the serum cholesterol level was 169 +/- 42 mg/dl (mean +/- SD). This decreased significantly (P less than .001) to 108 +/- 30 mg/dl after nine days' consumption of an isoenergetic-isonitrogenous diet in which whole wheat or white flour provided all the protein and +/- 50% of carbohydrate, and remained at this level for the 27-day dietary period. On changing again to the casein-based diet, the serum cholesterol level rose within nine days to 154 +/- 42 mg/dl. There was no similar diet-related change in serum triglyceride values. None of the known mechanisms whereby diet affects serum cholesterol adequately explains these findings.

Body Weight↗
PubMed1977

Postprandial plasma lysine as an indicator of dietary lysine adequacy in infants.

Postprandial plasma free amino acids were studied as an index of the level of dietary lysine. Fasting blood was obtained from 11 children who were then fed a meal in which wheat provided 100% of 0.4 g protein and 30% to 50% of 25 kcal/kg body weight. Blood samples were obtained 3 and 4 hours postprandially. Fasting blood samples were obtained from these same children after 9, 18 and 27 (n=6) days of consuming the same diet (2 g protein, 125 kcal/kg/day). Postprandial blood samples were taken from four additional children after consuming a meal containing 25 kcal and 0.75 g protein (0.5 g from wheat, 0.25 g casein)/kg. This meal was expected to provide adequate lysine while still maintaining lysine in lowest concentration among the essential amino acids relative to needs for protein synthesis. After consuming the unsupplemented wheat diet postprandial values showed a significant rise of total amino acids at 3 hours with a return to fasting levels at 4 hours. Total essential amino acids did not change at 3 or 4 hours. Lysine concentration was significantly lower at 3 and 4 hours. The ratio of lysine to total essential amino acids decreased at 3 and, more so, at 4 hours. In 3 of 4 children studied the postprandial decrease of plasma lysine and its molar fraction was not manifest after consuming wheat + casein. The fasting lysine concentration during continued wheat consumption showed no change at 9 days and then a progressive fall at 18 and 27 days. The results with wheat + casein lend support to the concept that a postprandial fall in the concentration of lysine and its molar fraction indicates not merely that lysine is present in lowest concentration but that it is present in inadequate concentration relative to needs for protein synthesis.

Amino Acids↗
PubMed1976

Growth and nitrogen retention of children consuming all of the day's protein intake in one meal.

To ascertain that linear growth and weight gain continue while consuming a diet in which all the day's protein is given in one meal, six children (ages: 8.5 to 25 months, weight: 6 to 8 kg) who were convalescing from malnutrition were placed on such a diet for 60 to 67 days. All diets provided 125 to 150 kcal and 2.0 to 2.5 g protein/kg/day, recalculated weekly. Energy was evenly divided among five feedings but the entire day's protein was given at the third meal. Increases in height age relative to increases in chronological age were appropriate for the stage of recovery. Height quotient (height age/chronological age times 100) increased during the study in four children and remained constant in two. Increases in weight age were greater than corresponding increases in chronological age. Nine-day control periods prior to and after the growth study allowed comparative N balances, which confirmed previous findings that apparent N retention from the unevenly distributed protein (32 +/- 10% of intake) was less, although not significantly so, than that from the control diet (34 +/- 15% of intake). Fecal facts were elevated during the study period (18 +/- 7.5% of intake) relative to the control period values (9 +/- 3.9% of intake) in all but one child.

Body Height↗
PubMed1976

Evaluation of isoosmotic tube feeding formula in the diets of convalescent malnourished infants and children.

The quality of the protein in a complete tube feeding formula intended for use in adults was evaluated in convalescent malnourished children. The casein-soy protein isolate blend was found to be similar to casein by comparative nitrogen balance studies carried out in five children, with protein providing 6.4% of calories. Three- and four-hour postprandial plasma free amino acid determinations at the same level of protein intake did not show the drop of plasma free methionine or of the methionine/total essential amino acid molar fraction characteristically seen when this amino acid is first limiting for protein synthesis. Three additional children were fed the formula, altered only by the addition of water, for periods of up to 3.6 months to test the tolerance to and completeness of the diet. No untoward effects nor signs of specific nutrient deficiency were encountered. Linear growth was appropriate for the stage of recuperation. The failure to achieve a normal (greater than 3.8 g/dl) serum albumin concentration in two of the three children may have been due to their rapid weight gain. Although it is intended for the adult, our results indicate that the formula could meet the nutritional requirements of infants and children.

Amino Acids↗
PubMed1976

Postprandial glucose, insulin, free fatty acid and growth hormone responses in children consuming all the day's protein in one meal.

BLOOD GLUCOSE, INSULIN (IRI), growth hormone, and plasma free fatty acids (FFA) were determined in six children consuming a diet of uneven distribution of protein relative to energy (study period). Preprandial and postprandial samples surrounding the 8 AM protein-free feeding and the 3 PM feeding containing all the day's protein were compared with values obtained in the same children similarly sampled while consuming an isonitrogenous isoenergetic diet of even protein distribution (control period). After the 8 AM feeding during the study period there was a mean maximal rise of blood glucose at 30 min of 51 mg/dl compared with a rise of 16 mg/dl during the control period. Glucose remained significantly elevated above fasting values at 120 min during the study but not the control period. IRI response after the 8 AM feeding was significantly greater and suppression of FFA was more marked during the study than during the control period. Glucose concentration 30 min after the 3 PM feeding was significantly lower during the study period than during the control period. A peak value occurred at 60 min during the study period which was equal to the 30 min peak control value. Despite the slower elevation of blood glucose during the study period, IRI rose at 30 min, possibly related to a larger influx of amino acids from the protein-containing meal. FFA rose at 30 and 60 min and were then suppressed by the slowly rising blood glucose. Growth hormone after both meals while consuming both diets was variable but considered normal. The qualitative changes in glucose-IRI-FFA responses were for the most part attributable to differences in the test meals and suggested little long-term adaptation to the uneven protein distribution diet.

Adaptation, Physiological↗
PubMed1976

Plasma amino acids of infants consuming soybean proteins with and without added methionine.

Fasting plasma free amino acids were determined in 54 convalescent malnourished infants: seven infants while consuming a diet based on isolated soybean protein, containing 4.0% to 5.3% of dietary metabolizable energy (calories) as protein (A), 20 at 6.4% to 6.7% protein calories (B), 23 at 6.4% to 6.7% protein calories with added DL-methionine (C), and four with 8.0% to 12.3% protein calories (D). There were no differences in total amino acid concentration (TAA) among the four groups; the molar fraction of essential amino acids (EAA:TAA) was lower for group A; there were no differences among the four groups in Lys:EAA or 1/2 cystine:EAA ratios or in Met concentration. Met:EAA was higher in C than B, with considerable overlap of individual values. In 10 of 13 infants who were represented in both B and C, Met concentration and Met:EAA ratio were higher in group C. Fasting plasma AA levels are not consistently reliable for field or clinical assessment of dietary Met adequacy. Fasting and postprandial (3- and 4-hour) plasma AA were determined in 29 infants: in 12 the preceding diet and the test meal were both Met-deficient with less than 6.7% protein calories (E), in five the preceding diet was milk-based but the test meal was Met-deficient at less than 6.7% (F), in five the preceding diet and test meal were based on isolated soybean protein at less than 6.7% with DL-Met added (G), and in seven the test meal was soy-based with greater than 9.0% protein calories (H). Plasma Met concentration and Met:EAA fell significantly at 3 and 4 hours in groups E and F, but not in groups G and H, suggesting that a postprandial fall in Met:EAA ratio can be used to identify dietary Met deficiency in field situations.

Amino Acids↗
PubMed1975

Evaluation of a low-lactose nutritional supplement in malnourished children.

A low-lactose food supplement was evaluated. Severely malnourished patients initially managed on the diet had uneventful courses of recovery, although serum cholesterol remained elevated after serum triglycerides had returned to normal. Nitrogen retention in convalescent malnourished children was slightly inferior to the casein-based control diet. Postprandial determinations of plasma amino acids suggested that the sulfur-containing amino acids were first-limiting in the product. The sattsfactory performance under these stringent test conditions, however, suggested that the product would serve well its intended purpose as a dietary supplement.

Acute Disease↗