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Biomedical subjects

I J Holt

Publications and source records attributed to I J Holt.

41 records · Page 3Linked to original sources
PubMed1989

Tyrosine hydroxylase and levodopa responsive dystonia.

It has been suggested that a form of inherited dystonia responsive to levodopa might be due to an abnormality of tyrosine hydroxylase gene. This hypothesis has been tested using a cDNA tyrosine hydroxylase gene probe in three families with this disorder. No evidence for genetic linkage between the disease and tyrosine hydroxylase loci was found; it is possible that the disorder results from a post-transcriptional defect confined to the brain.

Chromosome Mapping↗
PubMed1988

Deletions of muscle mitochondrial DNA in patients with mitochondrial myopathies.

In vitro studies of muscle mitochondrial metabolism in patients with mitochondrial myopathy have identified a variety of functional defects of the mitochondrial respiratory chain, predominantly affecting complex I (NADH-CoQ reductase) or complex III (ubiquinol-cytochrome c reductase) in adult cases. These two enzymes consist of approximately 36 subunits, eight of which are encoded by mitochondrial DNA (mtDNA). The increased incidence of maternal, as opposed to paternal, transmission in familial mitochondrial myopathy suggests that these disorders may be caused by mutations of mtDNA. Multiple restriction endonuclease analysis of leukocyte mtDNA from patients with the disease, and their relatives, showed no differences in cleavage patterns between affected and unaffected individuals in any single maternal line. When muscle mtDNA was studied, nine of 25 patients were found to have two populations of muscle mtDNA, one of which had deletions of up to 7 kilobases in length. These observations demonstrate that mtDNA heteroplasmy can occur in man and that human disease may be associated with defects of the mitochondrial genome.

Adult↗
PubMed1988

Mitochondrial DNA polymorphism in mitochondrial myopathy.

In order to test the hypothesis that mitochondrial myopathy may be caused by mutation of the mitochondrial (mt) genome, restriction fragment length polymorphism in leucocyte mt DNA has been studied in 38 patients with mitochondrial myopathy, 44 of their unaffected matrilineal relatives, and 35 normal control subjects. Previously unreported mt DNA polymorphisms were identified in both patients and controls. No differences in restriction fragment patterns were observed between affected and unaffected individuals in the same maternal line, and there was no evidence of major deletion of mt DNA in patients. This study provides no positive evidence of mitochondrial inheritance in mitochondrial myopathy, but this has not been excluded.

DNA, Mitochondrial↗
PubMed1988

Restriction endonuclease analysis of leukocyte mitochondrial DNA in Leber's optic atrophy.

In order to test the hypothesis that Leber's optic atrophy may be caused by mutation of the mitochondrial (mt) genome, restriction fragment length polymorphism in leukocyte mt DNA was studied in 16 patients with Leber's optic atrophy, 28 of their unaffected matrilineal relatives, and 35 normal control subjects. No differences in restriction fragment patterns were observed between affected and unaffected individuals in the same maternal line, and there was no evidence of major deletion of mt DNA in patients. This study provides no positive evidence of mitochondrial inheritance in Leber's optic atrophy but does not exclude it.

Adult↗