ABSTRACT
Screening for metabolic diseases at Children's Hospital of Michigan, Detroit during 1978 and 1979 led to the discovery of 7.5 cases per year, representing a marked increase over previous years. Five cases of organic aciduria were identified during this two-year period by use of urinary gas chromatography. Four of these were found to have methylmalonic aciduria. The increase in detection rate was due to the addition of an organic acid screening technique and greater use of two standard screening tests. The yield of screening by these two tests also improved, which we attribute to the better use of specific criteria. Inclusion of a simple urine screening test for methylmalonic acid is recommended in the workup of infants with episodic vomiting, lethargy, acidosis, or catastrophic illness.
Subject(s)
Metabolism, Inborn Errors/diagnosis , Amino Acid Metabolism, Inborn Errors/diagnosis , Amino Acids/blood , Amino Acids/urine , Hospitals, Municipal , Humans , Infant, Newborn , Metabolism, Inborn Errors/epidemiology , Methods , Methylmalonic Acid/urine , Michigan , RiskABSTRACT
In order to manipulate cell size and cell number, rats were subjected to nutrient restriction either prenatally and until weaning at 3 weeks (group I), or from 3 until 10 weeks (group II). Body weights of group I rats were 30% of normal at the height of deprivation at 3 weeks. By 16 weeks of age maximum weights were reached, which remained subnormal in the majority; by 26 weeks only one of six had attained a normal weight. Body weights of group II were 27% of normal at the height of deprivation at 10 weeks; subsequently, only one of six did not recover. The weight, protein, and DNA content of liver, kidney, and heart were significantly decreased. The combined weight and protein content of the three organs was 30% of normal in group I and 25% of normal in group II; the DNA content of the three organs was 57% and 38% of normal in group I and group II, respectively. The greater deficit in weight than DNA content, and the mean protein/DNA ratios reflect a decrease in cell size (or increase in the cell density) of the three organs, which was greater in group I (60%) than group II (71%). Muscle cell density was increased in group I, but not in group II. At 16 weeks of age all parameters were similar in the two experimental groups (ranging from 68% to 82% or normal). Organ weight, protein, and DNA content remained deficient only in group I; these values were 74%, 70%, and 77% of normal, respectively, at 32 weeks. The deficit was proportionate to the deficit in body weight. The basal metabolic rate was measured 17-20 hr after food removal (BMR) on the day the animals were killed. In group I and II correlations between the BMR and four parameters of body composition were linear during a 4-period at the height of deprivation. Comparison of means from the regressions showed no difference between group I and II, or between these groups and normal controls with regard to the BMR per body weight, organ weight, and organ protein. The BMR per mg DNA was lower in group I and II than in normal control rats (P less than 0.05). The BMR of normal rats age 3-32 weeks showed a curvilinear correlation with body weight (BWt), BMR = 1.24 BWt0.583; organ weight (OWt), BMR = 4.30 OWt0.766; and organ protein (OPr), BMR = 4.30 OPr0.604. By contrast, the regression on DNA was linear (BMR = 7.97 + 0.449), although marked changes in body composition occurred between 3 and 32 weeks.
Subject(s)
Body Composition , Brain/metabolism , DNA/metabolism , Kidney/metabolism , Liver/metabolism , Nutrition Disorders/metabolism , Proteins/metabolism , Animals , Body Weight , Brain/anatomy & histology , Female , Growth , Heart/anatomy & histology , Kidney/anatomy & histology , Liver/anatomy & histology , Male , Myocardium/metabolism , Organ Size , RatsABSTRACT
Measurement of the basal metabolic rate (BMR) and the total and free serum thyroxine values in response to feeding are aids in the diagnosis of growth failure. Infants with small-for-gestational-age dwarfism gained weight poorly in the hospital, had a low BMR before and after spontaneous or induced weight gain, and a normal serum thyroxine value. Infants with linear growth failure due to chronic malnutrition had a normal BMR but a low serum thyroxine value that rose to normal with weight gain; infants with clinical signs of recent weight loss had a low BMR and a low serum thyroxine value, both of which rose to normal with weight gain. Increases of the BMR were sharp and very rapid; they preceded the rise of the serum thyroxine value in some cases.
