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D L Valle

Publications and source records attributed to D L Valle.

16 recordsLinked to original sources
PubMed1988

Therapeutic approaches to cobalamin-C methylmalonic acidemia and homocystinuria.

The use of hydroxocobalamin (OH-B12), betaine, carnitine, and folinic acid were studied in two children with the cobalamin C form of methylmalonic acidemia and homocystinuria. When daily injections of 1 mg OH-B12 were discontinued for 3 weeks, there was no significant change in total plasma homocysteine or methionine levels and only a modest increase in methylmalonate. Orally administered OH-B12 1 mg/d in one patient was associated with an increase in plasma homocystine and a decrease in methionine within 1 month. Withdrawal of betaine 250 mg/kg/d was also associated with a rise in plasma homocystine and a fall in methionine levels. Carnitine 100 mg/kg/d lead to an increase in urinary excretion of propionylcarnitine, but did not affect plasma methylmalonate levels. No beneficial biochemical effect of folinic acid could be documented at a dose of 25 mg/d. Our results suggest that daily injections of OH-B12 are not necessary to maintain metabolic control and that orally administered OH-B12 is unlikely to be effective. Betaine appears to act synergistically with OH-B12 and should be part of the treatment regimen. Although there are theoretical reasons for using L-carnitine and folinic acid, we could not document their effectiveness in these two patients.

Administration, Oral↗
PubMed1986

Waste nitrogen excretion via amino acid acylation: benzoate and phenylacetate in lysinuric protein intolerance.

Benzoate and phenylacetate improve prognosis in inherited urea cycle enzyme deficiencies by increasing waste nitrogen excretion as amino acid acylation products. We studied metabolic changes caused by these substances and their pharmacokinetics in a biochemically different urea cycle disorder, lysinuric protein intolerance (LPI), under strictly standardized induction of hyperammonemia. Five patients with LPI received an intravenous infusion of 6.6 mmol/kg L-alanine alone and separately with 2.0 mmol/kg of benzoate or phenylacetate in 90 min. Blood for ammonia, serum urea and creatinine, plasma benzoate, hippurate, phenylacetate, phenylacetylglutamine, and amino acids was obtained at 0, 120, 180, and 270 min. Urine was collected in four consecutive 6-h periods. Alanine caused hyperammonemia: maximum increase 107, 28-411 microM (geometric mean, 95% confidence interval); ammonia increments were nearly identical after alanine + benzoate (60, 17-213 microM) and alanine + phenylacetate (79, 13-467 microM) (NS). Mean plasma benzoate was 6.0 mM when extrapolated to the end of alanine + benzoate infusions; phenylacetate was 4.9 mM at the end of alanine + phenylacetate. Transient toxicity (dizziness, nausea, vomiting) occurred in four patients at the end of combined infusions, and we suggest upper therapeutic plasma concentrations of 4.5 mM for benzoate and 3.5 mM for phenylacetate. Benzoate and phenylacetate then decreased following first-order kinetics with t1/2S of 273 and 254 min, respectively. Maximal plasma hippurate (0.24, 0.14-0.40 mM) was lower than maximal phenylacetylglutamine (0.48, 0.22-1.06 mM, p = 0.008).(ABSTRACT TRUNCATED AT 250 WORDS)

Acylation↗
PubMed1985

Niemann-Pick disease--type C. Ocular histopathologic and electron microscopic studies.

The presence of lipid storage was demonstrated in type C Niemann-Pick disease by histopathologic and ultrastructural studies. Pleomorphic membranous inclusions, with variable proportions of light and dark granular material, were observed within the conjunctival fibrocytes, endothelial cells and pericytes, keratocytes, lens epithelium, retinal ganglion cells, retinal pigment epithelium, fibrocytes in the uveal tract, and optic nerve fibrous astrocytes. Only optic nerve and retinal ganglion cell involvement had clinical counterparts represented by optic nerve pallor and perimacular gray discoloration.

Child↗
PubMed1984

Mutant cell lines resistant to azetidine-2-carboxylic acid: alterations in the synthesis of proline from glutamic acid.

Two mutant Chinese hamster lung fibroblast lines have been isolated that are resistant to the toxic proline analog L-azetidine-2-carboxylic acid. The line designated AZCA-1 has 30-fold elevated activity of pyrroline-5-carboxylate synthase and a large increase in the rate of proline production and release compared to controls. Pyrroline-5-carboxylate synthase activity is not elevated in the resistant line designated AZCA-4, but the enzyme is less sensitive to inhibition by ornithine and proline than control enzyme. Intracellular proline is elevated in AZCA-4 cells, with no change in the rate of release of proline synthesized from glutamate. Resistance to azetidine carboxylic acid in both mutant lines is attributed to the expanded intracellular proline pool that results from alterations in pyrroline-5-carboxylate synthase. These results indicate that intracellular proline levels are determined at least in part by the regulated activity of pyrroline-5-carboxylate synthase.

Animals↗
PubMed1983

Aspartylglucosaminuria in the United States.

Aspartylglucosaminuria (AGU) was diagnosed in two unrelated males with progressive mental retardation, coarse facies and skeletal abnormalities. Until now, this disorder has been described in predominantly Finnish populations with only one previous case reported in the U.S. We conclude that AGU may be more common in non-Finnish populations than the number of reported cases would indicate and should be included in the differential diagnosis in patients with suspected lysosomal storage disorders regardless of their geographical or ethnic backgrounds.

Adolescent↗
PubMed1981

Gyrate atrophy of the choroid and retina in a cat.

An adult male, domestic short-haired cat with generalized retinal atrophy was found to have a 60-fold increase in plasma ornithine and ornithinuria. Ornithine-8-aminotransferase activity was undetectable in its tissues and in its cultured skin fibroblasts. This feline condition is thus analogous to gyrate atrophy of the choroid and retina in humans.

Amino Acid Metabolism, Inborn Errors↗
PubMed1979

New pathways of nitrogen excretion in inborn errors of urea synthesis.

The defect in nitrogen excretion in patients with inborn errors of urea synthesis can be controlled by exploiting the biosynthetic pathways of readily excretable non-urea metabolites which contain nitrogen derived from ammonium, alanine, glutamate, and glutamine. Two classes of such metabolites are the urea-cycle intermediates--including citrulline, argininosuccinic acid, and arginine--and the aminoacid acylation products--hippuric acid (the glycine conjugate of benzoic acid) and phenylactylglutamine (the glutamine conjugate of phenylactic acid). Thus the urea cycle may serve as a model for the development of excretion pathways of toxic precursors which accumulate in inborn errors of metabolism.

Arginine↗
PubMed1975

Puromycin effect on amino acid transport: differential rates of carrier protein turnover.

In fetal rat calvaria, puromycin selectively inhibited the uptake of certain groups of amino acids. Puromycin treatment decreased the uptake of glycine, L-proline, and alpha-aminoisobutyric acid but was without effect on the active uptake of all other amino acids tested. In studies of alpha-aminoisobutyric acid uptake, puromycin decreased the maximal transport velocity by 70% but had no effect on the affinity of the transport system for the amino acid. With puromycin treatment, the fall-off in rates of alpha-aminoisobutyric acid uptake was first order with a half-life of 68 min. Insulin treatment increased this half-life to 118 min. These findings suggest that protein components of specific transport systems are degraded at varying rates after puromycin blockade of protein synthesis. Hormones that stimulate amino acid transport (e.g., insulin) may decrease the rate of degradation of these protein components.

Amino Acids↗
PubMed1975

A radioisotopic assay for proline oxidase activity.

We developed a radioisotopic assay for proline oxidase in which product deltal-pyrroline-5-carboxylate-14-C is reacted with o-aminobenzaldehyde and the radioactivity trapped as the dihydroquinazolinium compound is recovered by ion-exchange chromatography. The sensitivity of this method allows the measurement of proline oxidase activity in small specimens (10 to 20 mg.) of liver.

Amines↗
PubMed1974

Type 2 hyperprolinemia: absence of delta1-pyrroline-5-carboxylic acid dehydrogenase activity.

triangle up(1)-Pyrroline-5-carboxylic acid dehydrogenase activity was measured radioisotopically in normal and type 2 hyperprolinemia fibroblasts. The type 2 cells had no detectable activity over a range of reaction conditions whereas normal cells had easily measurable activity. This enzymatic defect accounts for the biochemical abnormalities in type 2 hyperprolinemia.

Adolescent↗