Biomedical subjects
Publications and source records attributed to L A Barness.
We report on 2 women with organic acidemias, one with classical maple syrup urine disease and another with mild propionic acidemia in which protein restricted diets and carnitine supplementation were successfully employed to manage pregnancies. Healthy infants were delivered without maternal metabolic decompensation.
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A 9-month-old boy presented with rapid deterioration of psychomotor development. He developed seizures at 2 months, and shortly thereafter lost motor skills and developed feeding difficulties, increased startle response, red maculas, and decreased vision. His measurements, including head circumference, were greater than the 95th centile. No organomegaly was found. Serum determination of the hemoxsaminidases confirmed the diagnosis of Sandhoff disease.
Flow cytometric analysis was performed on purified mononuclear cells isolated from whole blood samples of 11 adults, 7 breast-fed (BF) infants and 11 formula-fed (FF) infants, mean ages 34.2 +/- 4.3 years, 6.3 +/- 1.3 months, and 6.2 +/- 1.2 months, respectively. Infants were receiving at least 70% of calories from formula or breast milk. Infant mononuclear cell populations contained a higher percentage of lymphocytes and a lower percentage of monocytes compared with adults. Within the lymphocyte population, infants had a higher CD4+/CD8+ ratio (T helper-inducer/T cytotoxic-suppressor), a higher percentage of CD19+ (pan B) and CD4+ cells, and a lower percentage of CD8+ and CD16+ (natural-killer) cells compared with adults. CD3+ (pan T) and CD4+ lymphocyte percentages were higher and CD19+ lymphocyte percentages were lower in FF compared with BF infants. Although sample size is small, our data indicate that diet may influence lymphocyte subset distribution during infancy when the majority of calories is derived from infant formula or human milk.
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Of 52 infants who had died suddenly and were referred to autopsy, nine had lain on adult water beds for the first time; five had died as a result of accidents; two had died on water beds; two were in beds with widely spaced slats; and one had died as a result of strangulation. Three deaths were due to overlying. Three other infants had been placed on sheepskin rugs for the first time and were found dead shortly thereafter. These infants ranged in age from 2 to 9 months, except for a severely mentally retarded nine-year-old with spastic paraplegia. We believe that a general warning should be issued concerning water beds and that soft bedding should not be used for infants. Infants should not be placed unattended or left to sleep on water beds; only beds recommended for infants should be used. Overlying of a young infant is most likely to occur on a water bed, or if the parent is obese or has consumed alcohol.
Nucleotide (NT) nitrogen, a component of nonprotein nitrogen, accounts for approximately 0.1% to 0.15% of the total nitrogen content of human milk. The results of studies in animals indicate that dietary NTs may be required for maintenance of normal immune function. Thirty-seven healthy term infants were either breast-fed (n = 9) or fed SMA formula supplemented with 33 mg of NTs per liter (n = 13, NT+) or standard SMA formula (n = 15; NT-). At 2 months of age, natural killer cell percent cytotoxicity was significantly higher in the breast-fed and NT+ groups compared with the NT- group (41.7 +/- 4.7, 32.2 +/- 3.4, 21.7 +/- 2.2%, respectively). Interleukin-2 production by stimulated mononuclear cells was higher in the NT+ compared with the NT- group at 2 months of age (0.90 +/- 0.28 U/mL, 0.27 +/- 0.11 U/mL, respectively); neither formula-fed group differed significantly from the breast-fed group. Rate of growth and incidence and severity of infections did not differ significantly among dietary groups. Nucleotides may be a component of human milk that contributes to the enhanced immunity of the breast-fed infant.
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Recommendations for weaning have been based on empiric practices and observations of physiologic development. Estimates of nutritional requirements mimic those of the preweaning infant, adjusted for a slower growth rate. Concern for the onset of deficiency states (e.g., obesity, failure to thrive, atherosclerosis, hypertension) may provide scientific bases for nutritional recommendations during weaning.
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Autopsy of a 4-year-old girl with hereditary tyrosinemia type I revealed a hepatocellular carcinoma in addition to cirrhosis and renal tubular dysplasia. Cytogenetic studies performed on a skin fibroblast culture demonstrated greatly increased chromosome breakage, which affected 71% of the cells. This suggests that the development of hepatoma, which is frequent in this syndrome, and the presence of dysplastic changes of hepatocytes in nontumorous liver are related to genetic instability caused by accumulation of intermediates of tyrosine catabolism, which are natural alkylating agents (e.g., maleylacetoacetate and fumarylacetoacetate). The other microscopic structural changes seen, such as renal tubular atypia, pancreatic islet cell hyperplasia, and focal necrosis of cortical neurons, may also be partly due to DNA damage caused by the accumulation of abnormal metabolites produced in patients with type 1 tyrosinemia.
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The pathologic approach to the study of malformations and congenital abnormalities emphasizes the importance of careful dissection and pathologic studies. Concepts and terms of morphogenesis as defined by the International Working Group are presented. The developmental field is the central concept of a malformation. Malformation syndromes, disruptions, sequences, deformations, dysplasias, and associations are presented. The significance of fetal hydrops and short umbilical cord is discussed. Pathologic studies in chromosome defects suggest pathologic markers for some chromosome abnormalities.
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