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Biomedical subjects

L A Barness

Publications and source records attributed to L A Barness.

At least 19 recordsLinked to original sources
PubMed2000

Transcutaneous absorption of vitamin A in newborn rats.

Very low birth weight neonates have low tissue concentrations of vitamin A, which may contribute to the development of lung disease. These infants, however, may not receive vitamin A supplementation for several days after birth. We determined if the relatively permeable skin of a newborn could be used to administer vitamin A. 25 control rat pups were killed and lungs and livers were collected. 20 microl (1,000 IU) of retinyl palmitate were applied to the skin surface of an additional 50 two-day-old pups. At 2.5 and 5 h after application, 25 pups were killed, and lungs and livers were collected. Concentrations of retinyl palmitate and retinol were significantly higher in the lungs of pups 5 h after administration of vitamin A compared with controls. There were no differences in concentrations of retinyl palmitate or retinol in livers. We conclude that transcutaneous administration may be an effective means of delivering vitamin A to the lungs of newborn rats.

Absorption↗
PubMed1998

Aluminum toxicity.

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Abnormalities, Drug-Induced↗
PubMed1997

Functional methionine synthase deficiency due to cblG disorder: a report of two patients and a review.

Functional methionine synthase deficiency due to abnormal methylcobalamin metabolism causes megaloblastic anemia, moderate to severe developmental delay, lethargy, and anorexia in association with homocystinuria. Patients with this disorder of cobalamin metabolism can be classified into two separate groups, cblE or cblG, primarily on the basis of complementation analysis with cultured skin fibroblasts. We describe two unrelated boys, ages 3 and 5 years, with the cblG defect in methylcobalamin synthesis. Both children presented with severe developmental delay, lethargy, anorexia, and megaloblastic anemia. The diagnosis of homocystinuria was delayed in each case due to difficulties with detection of small amounts of homocystine in physiologic samples. The clinical course of cblG disease is favorably altered by treatment with intramuscular hydroxycobalamin. Megaloblastosis in the presence of adequate supplies of cobalamin and folate in the blood must alert the clinician to the possibility of functional methionine synthase deficiency and should prompt a careful search for associated biochemical hallmarks, including homocystinuria/emia.

5-Methyltetrahydrofolate-Homocysteine S-Methyltran↗
PubMed1996

Analyzing signs and symptoms of metabolic diseases.

Inborn metabolic errors, while not common, may have significant implications for patients. Those patients with such errors who have acute life-threatening symptoms must be treated immediately, and specimens for analysis should best be obtained during the critical stage. Many infants and children seen with acute symptoms are the ones most likely to have treatable diseases. At a more leisurely pace, other inborn errors can be diagnosed in order to provide appropriate counseling and prognosis.

Blood Chemical Analysis↗
PubMed1996

Trophic factors for the gastrointestinal tract.

GI trophic factors that influence the coordinated pre- and postnatal growth and development of the GI tract have been identified. Studies in animals and humans demonstrate that GI trophic factors can initiate cellular growth and expression of differentiated function, and they are important in adaptation and repair following injury. Systemically as well as enterally administered growth factors can stimulate GI growth and maturation, suggesting that trophic factors in the serum of neonates may modulate GI growth via receptors on the serosal membranes of enterocytes. GI trophic factors may be synthesized endogenously or provided postnatally in milk. GI trophic factors in human milk play an important role in regulating the adaptive functional changes that accompany the transition to postnatal enteral feedings. Although human milk growth factors do not appear to be essential for infant survival, the elevated risk of gastrointestinal-related illnesses in formula-fed as compared with breast-fed infants (diarrhea, necrotizing enterocolitis, colitis, Crohn's disease) suggest that bioactive compounds in human milk contribute to the apparent protective effect of breast feeding. GI trophic factors have the potential to be used therapeutically to enhance GI maturation and repair following injury. These applications may be particularly useful in the premature or postsurgical infant. Several issues require further research, including (1) the mechanism of action, (2) the efficacy of oral versus systemic administration, (3) characterization of the complex interactions between the various growth factors, because some appear to act synergistically, (4) the effect of exogenously administered growth factors on endogenous production of that factor, its receptor, or other growth factors, (5) the effect of growth factors upon tissues not directly associated with the GI tract, and (6) the determination of safe and effective upper limits.

Animals↗
PubMed1994

Nutritional requirements of infants and children with respect to cholesterol and related compounds.

Cholesterol is an enigmatic, essential metabolite. Breast milk contains significant quantities of cholesterol, yet human infants thrive on cholesterol-free diets. Recommendations to lower serum cholesterol are widespread, yet low serum cholesterol is associated with poorly understood morbidity. Serum cholesterol is increased with diets high in fat, yet dietary cholesterol has relatively little effect on serum concentrations. Smith-Lemli-Opitz syndrome, marked with extremely low serum cholesterol, may serve as a human model for the evaluation of absorption and metabolism of dietary cholesterol.

Cell Membrane↗
PubMed1994

Nutrition update.

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Adolescent↗
PubMed1993

The mucolipidoses.

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Histocytochemistry↗