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D A Applegarth

Publications and source records attributed to D A Applegarth.

At least 19 recordsLinked to original sources
PubMed1994

Murine alpha-L-iduronidase: cDNA isolation and expression.

As an initial step toward the generation of a murine model for mucopolysaccharidosis type I, we have identified and characterized a full-length murine alpha-L-iduronidase cDNA. Expression of the murine cDNA in COS-1 cells results in the production of alpha-L-iduronidase enzyme activity at a level 20-fold higher than that of the endogenous gene. The murine cDNA shows strong homology with the coding region of both the human and the canine homologs with 78 and 75% nucleotide sequence identity, respectively. In contrast to the coding region, significant diversity of sequence exists for the 5' and 3' untranslated regions between the murine and both the human and the canine sequence. The 3' UTR of the murine transcript is 1193 bp in length, as compared to the human (100 bp) and canine (139 bp), and contains a CA dinucleotide repeat not seen in either the human or the canine genes. A portion of the murine iduronidase coding sequence overlaps with sequence reported for the 3' UTR of the murine SAT-1 cDNA. The sequence overlap involves the proposed exon II of murine iduronidase and covers 141 bp of sequence with the transcripts generated in opposite orientation. We report here the characterization of murine alpha-L-iduronidase cDNA and its relationship to SAT-1.

Animals↗
PubMed1992

Prenatal diagnosis of non-ketotic hyperglycinaemia.

Non-ketotic hyperglycinaemia (NKH) is a devastating neurological disease for which there is no effective therapy. Consequently, most couples with a pregnancy known to be at risk for NKH request prenatal diagnosis. We have applied the combination of chorionic villus (CVS) assay for glycine cleavage enzyme activity and determination of amniotic fluid glycine concentration to increase the reliability of prenatal diagnosis for this disorder beyond that of each of these methods alone. All 15 of the at-risk pregnancies monitored had CVS glycine cleavage assay and five also had amniotic fluid glycine measurements. Two cases had no detectable cleavage activity in CVS and one gave uninterpretable enzyme results. Amniotic fluid glycine concentration was increased in all three and NKH was confirmed by abortus tissue assays for cleavage activity and amino acids. The remaining 12 case had activity in CVS (two also had normal amniotic fluid glycine levels) and delivered unaffected infants. Four of these 12 cases had cleavage activities below or at the low end of the normal range, perhaps indicating carrier status. We believe that the combination of CVS glycine cleavage assay and amniotic fluid glycine measurement is currently the best approach to the prenatal diagnosis of NKH.

Amino Acid Metabolism, Inborn Errors↗
PubMed1991

Prenatal diagnosis of molybdenum cofactor deficiency by assay of sulphite oxidase activity in chorionic villus samples.

Molybdenum cofactor deficiency is characterized by the absence of sulphite oxidase, xanthine dehydrogenase and aldehyde oxidase, the three known enzymes in man that require the cofactor for their activity. Prenatal diagnosis of the deficiency may be performed by assay of sulphite oxidase activity in cultured amniocytes. However, the activity in amniocytes is low and large numbers of cells are required for reliable assessment. We show that sulphite oxidase is present at high levels in chorionic villi obtained at 10-14 weeks gestation and can be assayed directly in the biopsy sample without cell culture. This assay has been applied to two pregnancies at risk for molybdenum cofactor deficiency with successful diagnoses of an unaffected and an affected fetus.

Aldehyde Oxidase↗
PubMed1990

Biochemical investigation of a child with molybdenum cofactor deficiency.

A girl aged eight months, who presented with developmental delay and dislocated optic lenses, was diagnosed as having combined sulfite oxidase and xanthine dehydrogenase deficiencies consistent with molybdenum cofactor deficiency. The diagnosis was confirmed by demonstrating the absence in urine of urothione, a molybdenum cofactor metabolite. Prenatal diagnosis excluded the disease in the mother's second pregnancy. A summary of an in vitro study of molybdenum cofactor synthesis in the patient is given.

Coenzymes↗
PubMed1990

Congenital rubella syndrome associated with calcific epiphyseal stippling and peroxisomal dysfunction.

An infant girl had the clinical and immunologic findings of congenital rubella syndrome but also had arthrogryposis multiplex and calcific epiphyseal stippling. Spastic quadriparesis developed, and both physical and behavioral development were slow. Increased spasticity of the legs at 5 1/2 years was related not to progressive rubella encephalomyelopathy but to spinal cord compression by abnormal cartilaginous tissue. The presence of a peroxisomal disorder was demonstrated by a greatly increased level of phytanic acid and slightly increased levels of hexacosanoate in serum and by reduced activity of peroxisomal dihydroxyacetone phosphate acyltransferase and a slightly increased ratio of cytosolic to peroxisomal catalase activity in cultured fibroblasts. A reduction in the number and size of peroxisomes was demonstrated in cultured fibroblasts, and a needle biopsy specimen of the liver also showed the peroxisomes to have a smaller diameter than usual. We recommend that any child with epiphyseal stippling be assessed for peroxisomal disease and that the potential for spinal cord compression by dysplastic bone or cartilage be recognized. The association of peroxisomal dysfunction with congenital rubella has not been described previously. The interaction between rubella virus infection and peroxisomal function may need further investigation.

Calcinosis↗
PubMed1990

The high incidence of valproate hepatotoxicity in infants may relate to familial metabolic defects.

The incidence of fatal hepatic failure associated with valproic acid (VPA) therapy is highest in children under the age of three years, particularly in those with developmental delay. The pathogenesis of VPA hepatotoxicity is unclear but may relate to the accumulation of a toxic metabolite of VPA which impairs fatty-acid oxidation. We describe two unrelated infants with developmental delay who developed hepatic failure while receiving VPA. Siblings of both children subsequently developed hepatic steatosis and intractable seizures without being exposed to VPA. This suggests that the two children who developed liver failure when receiving VPA may have had a familial metabolic disorder. Familial metabolic disorders may account partly for the higher incidence of fatal hepatotoxicity described in infants receiving VPA.

Chemical and Drug Induced Liver Injury↗
PubMed1989

Use of placental enzyme analysis in assessment of the newborn at risk for non-ketotic hyperglycinaemia (NKH).

The incidence of non-ketotic hyperglycinaemia (NKH), McKusick 23830, in the population of British Columbia, Canada was found to be the same as that reported for Finland. We present the plasma glycine levels in ten non-ketotic hyperglycinaemia patients and outline difficulties in interpreting plasma glycine levels in their newborn siblings. We propose the use of a placental glycine cleavage enzyme (EC 2.1.1.10) assay to rule out a diagnosis of non-ketotic hyperglycinaemia in at-risk infants during the first few days of life.

Amino Acid Metabolism, Inborn Errors↗
PubMed1989

Laboratory detection of metabolic disease.

This article describes the clinical signs, abnormal chemistry, histopathology, and biochemical tests that assist in the diagnosis of many inherited metabolic diseases. Small molecule diseases (for example, amino acid disorders, organic acidurias, and galactosemia) may present with acute illness and lead to unexplained death. Diagnosis of the specific enzyme defect may permit treatment by dietary changes or vitamin supplementation. Large molecule diseases are degenerative disorders due to storage of glycogen, glycoproteins, or mucopolysaccharides. Table 7 presents a compendium of laboratory investigations one should consider using when abnormalities are found in multiple organ systems. The investigation of a child with a mucopolysaccharidosis is used as an example of the use of this table. Investigating pediatricians should realize that many laboratory tests involved in the diagnosis of metabolic disease required special collection and handling by the laboratory.

Amino Acid Metabolism, Inborn Errors↗
PubMed1988

Interstitial 7q deletion [46,XX,del(7)(pter----q21.1::q22----qter)] and the location of genes for beta-glucuronidase and cystic fibrosis.

We report on a patient with a de novo chromosome abnormality del(7)(q21.1q22). The cells of this patient were used to determine the assignment of the gene for the enzyme beta-glucuronidase and the DNA probes around the cystic fibrosis gene--pJ3.11 and metH. Both the beta-glucuronidase gene and the DNA probes pJ3.11 and metH were found in 2 copies in our patient, indicating that neither locus lies in the deleted segment.

Chromosome Deletion↗