Search

Your search keyword '"Heales S"' showing total 440 results
Start Over Author "Heales S"
440 results on '"Heales S"'

1. Production of Stable Solutions of 7,8-Dihydropterin

Author

Heales S. J. R. and Hyland K.

Subjects
Crystallography, QD901-999
Abstract

In aqueous solution, 7,8-dihydropterin is hydrated to 6-hydroxy-5,6,7,8-tetrahydropterin. At neutral pH the equilibrium between these two species lies predominantly towards 7,8-dihydropterin, but autoxidation of 6- hydroxy-5,6,7,8-tetrahydropterin to 7,8-dihydroxanthopterin disrupts the equilibrium resulting in further 7,8- dihydropterin hydration. Oxidation of 5,6,7,8-tetrahydropterin, at pH 6.8, by ferricyanide or dichlorophenolindolphenol, followed by a period of time for quinonoid dihydropterin rearrangement, is shown to result in a solution consisting predominantly of 7,8-dihydropterin. At 37 °C, the 7,8-dihydropterin content rapidly decreases with a corresponding increase in 7,8-dihydroxanthopterin. Addition of dithioerythritol to a 7,8- dihydropterin solution prevents 6-hydroxy-5,6,7,8-tetrahydropterin oxidation, resulting in a stable solution consisting predominantly of 7,8-dihydropterin.

Published
1989
Full Text
View/download PDF

12. Erratum: Consensus guideline for the diagnosis and treatment of tetrahydrobiopterin (BH4) deficiencies (Orphanet Journal of Rare Diseases (2020) 15: 126 DOI: 10.1186/s13023-020-01379-8)

Author

Opladen, T. López-Laso, E. Cortès-Saladelafont, E. Pearson, T.S. Sivri, H.S. Yildiz, Y. Assmann, B. Kurian, M.A. Leuzzi, V. Heales, S. Pope, S. Porta, F. García-Cazorla, A. Honzík, T. Pons, R. Regal, L. Goez, H. Artuch, R. Hoffmann, G.F. Horvath, G. Thöny, B. Scholl-Bürgi, S. Burlina, A. Verbeek, M.M. Mastrangelo, M. Friedman, J. Wassenberg, T. Jeltsch, K. Kulhánek, J. Kuseyri Hübschmann, O.

Abstract

Following the original article's publication [1] the authors asked for the correction of Fig. 2, since the names of the disease genes [GCH1 and PCBD1] in the figure published did not match the listed diseases [AR-GTPCHD and PCDD]. The correct Fig. 2 isshown below: In the context of the manuscript correction and inorder to match he text content, the words "apart from DHPRD" should be removed from the second row and second column of Table 4, as shown below: (Table Presented). © 2020 The Author(s). Reference.

Published
2020

13. Consensus guideline for the diagnosis and treatment of tetrahydrobiopterin (BH4) deficiencies (vol 15, 126, 2020)

Author

Opladen T, López-Laso E, Cortés-Saladelafont E, Pearson TS, Sivri HS, Yildiz Y, Assmann B, Kurian MA, Leuzzi V, Heales S, Pope S, Porta F, Garcia-Cazorla A, Honzík T, Pons R, Regal L, Goez H, Artuch-Iriberri R, Hoffmann GF, Horvath G, Thöny B, Scholl-Bürgi S, Burlina A, Verbeek MM, Mastrangelo M, Friedman J, Wassenberg T, Jeltsch K, Kulhánek J, Kuseyri Hübschmann O, and International Working Group on Neurotransmitter related Disorders (iNTD)

Published
2020

24. Cerebral folate deficiency: Analytical tests and differential diagnosis

Author

Pope S, Artuch-Iriberri R, Heales S, and Rahman S

Subjects
5-MTHF, mitochondrial disease, one carbon metabolism, FOLR1, folinic acid, vitamin B9, 5-methyltetrahydrofolate, DHFR, folate, PCFT
Abstract

Cerebral folate deficiency is typically defined as a deficiency of the major folate species 5-methyltetrahydrofolate in the cerebrospinal fluid (CSF) in the presence of normal peripheral total folate levels. However, it should be noted that cerebral folate deficiency is also often used to describe conditions where CSF 5-MTHF is low, in the presence of low or undefined peripheral folate levels. Known defects of folate transport are deficiency of the proton coupled folate transporter, associated with systemic as well as cerebral folate deficiency, and deficiency of the folate receptor alpha, leading to an isolated cerebral folate deficiency associated with intractable seizures, developmental delay and/or regression, progressive ataxia and choreoathetoid movement disorders. Inborn errors of folate metabolism include deficiencies of the enzymes methylenetetrahydrofolate reductase, dihydrofolate reductase and 5,10-methenyltetrahydrofolate synthetase. Cerebral folate deficiency is potentially a treatable condition and so prompt recognition of these inborn errors and initiation of appropriate therapy is of paramount importance. Secondary cerebral folate deficiency may be observed in other inherited metabolic diseases, including disorders of the mitochondrial oxidative phosphorylation system, serine deficiency, and pyridoxine dependent epilepsy. Other secondary causes of cerebral folate deficiency include the effects of drugs, immune response activation, toxic insults and oxidative stress. This review describes the absorption, transport and metabolism of folate within the body; analytical methods to measure folate species in blood, plasma and CSF; inherited and acquired causes of cerebral folate deficiency; and possible treatment options in those patients found to have cerebral folate deficiency.

Published
2019

28. Cytochrome c oxidase deficiency associated with the first stop-codon point mutation in human mtDNA

Author

Hanna, M.G., Nelson, I.P., Rahman, S., Lane, R.J.M., Land, J., Heales, S., Cooper, M.J., Schapira, A.H.V., Morgan-Hughes, J.A., and Wood, N.W.

Subjects
Genetic disorders -- Research, Mitochondrial DNA -- Research, Cytochrome oxidase -- Genetic aspects, Lactic acid -- Genetic aspects, Mutation (Biology) -- Research, Encephalopathy -- Genetic aspects, Muscles -- Abnormalities, Biological sciences
Abstract

A new mutational mechanism has been found in mitochondrial disease. The first stop-codon point mutation in mtDNA reported with human disease has been found. In a 36-year-old woman having encephalopathy episodes with exercise intolerance, lactic acidemia, and proximal myopathy, 90% of muscle fibers were found to have absent or lowered cytochrome c oxidase (COX) activity. Biochemical studies found a major isolated COX activity reduction. Muscle immunocytochemistry found a pattern indicating likely primary mtDNA defects in the COX-deficient fibers which would be consistent with impaired assembly or reduced stability of COX.

Published
1998

Catalog

Books, media, physical & digital resources
See catalog results