Evidence map›Paper›PMID 31720353›Full record

ArticlePractical laboratory medicine2020

Fluorimetric assay with a novel substrate for quantification of galactocerebrosidase activity in dried blood spot specimens.

Anirudh J Ullal, Hong Pham, Rajendra Singh, Peter Ross, Carrie A Graham, Scott M Norton, Miriam H Nuffer, Debbie S Burns, Allen E Eckhardt, Maria Escolar and 2 more

Open access · goldAbstract read
PubMed Full text at PMC Publisher
In one paragraph

Article in Practical laboratory medicine, 2020. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact, top 83% of its field
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed, 3 citations in OpenAlex.

  1. Article
  2. Review
4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

12 authors at 4 institutions in 1 country.

Anirudh J UllalBaebies, Inc., PO Box 14403, Durham, NC, 27709, USA.
Hong PhamBaebies, Inc., PO Box 14403, Durham, NC, 27709, USA.
Rajendra SinghBaebies, Inc., PO Box 14403, Durham, NC, 27709, USA.
Peter RossBaebies, Inc., PO Box 14403, Durham, NC, 27709, USA.
Carrie A GrahamBaebies, Inc., PO Box 14403, Durham, NC, 27709, USA.
Scott M NortonBaebies, Inc., PO Box 14403, Durham, NC, 27709, USA.
Miriam H NufferBaebies, Inc., PO Box 14403, Durham, NC, 27709, USA.
Debbie S BurnsBaebies, Inc., PO Box 14403, Durham, NC, 27709, USA.
Allen E EckhardtAdvanced Liquid Logic Inc., PO Box 14025, Durham, NC, 27709, USA.
Maria EscolarUniversity of Pittsburgh, One Children's Hospital Way, 4401 Penn Ave, Pittsburgh, PA, 15224, USA.
Deeksha BaliDuke University, Biochemical Genetics Laboratory, 801 Capitola Dr., Suite 6, Durham, NC, 27713, USA.
Vamsee K PamulaBaebies, Inc., PO Box 14403, Durham, NC, 27709, USA.
Baebies (United States) · USAdvanced Liquid Logic · USDuke University · USUniversity of Pittsburgh · US

Funding

Lab-on-a-Chip for Multiplexed Newborn Screening of Lysosomal Storage DisordersR44HD057713 · NICHD · BAEBIES, INC. · PI PAMULA, VAMSEE K. · 2009 to 2014
$3.9M
NICHD NIH HHS R44 HD057713
6 · The paper itself

Abstract

backgroundDecreased galactocerebrosidase (GALC) enzyme activity is causative for Krabbe disease, a lysosomal storage disorder with devastating neurodegenerative consequences. Quantitative fluorimetric assays for GALC activity in isolated blood and skin cells have been described; however, no such assay has been described using dried blood spot (DBS) specimens.

methodsGALC enzyme activity was measured quantitatively using fluorescence from a novel glycosidic substrate: carboxy derived from 6-hexadecanoylamino-4-methylumbelliferone. GALC activity was demonstrated on newborn DBS specimens, known Krabbe disease patient specimens, proficiency testing and quality control samples.

resultsWe present data on characterization of the novel substrate and assay, including pH optimization and enzyme kinetics using a fluorimetric profile. Single and multi-day precision analyses revealed tight analytical measurements with %CV ranging from 5.2% to 14.1%. GALC enzyme activity was linear over the range of 0.31 - 12.04 μmol/l/h with a limit of detection of 0.066 μmol/l/h. Our results with this assay show a clear discrimination between GALC activities in samples from Krabbe disease patients versus presumed normal newborn samples.

conclusionsA fluorimetric assay for GALC enzyme activity measurement on dried blood spot specimens is feasible. Improvements to the assay including novel substrate design, increased substrate concentration and removal of sodium chloride maximize the specificity of the assay and minimize interference from β-galactosidase.

Indexed as

CHMU, 3-Carboxy 6-hexadecanoylamino-4-methylumbelliferoneCHMUG, 3-Carboxy 6-hexadecanoylamino-4-methylumbelliferone β-D-galactopyranoside substrateCLSI, Clinical and Laboratory Standards InstituteDBS, Dried blood spotDried blood spotFluorescence enzyme assayGalactocerebrosidaseGALC, galactocerebrosidaseHMU, 6-hexadecanoylamino-4-methylumbelliferoneHMUG, 6-hexadecanoylamino-4-methylumbelliferone β-D-galactopyranoside substrateKrabbe diseaseLoB, Limit of the blankLoD, Limit of detectionLoQ, Limit of quantitationMUG, 4-methylumbelliferyl-β-D-galactopyranoside substrateNBS, Newborn screeningNEH, Non-enzymatic hydrolysisNewborn screeningPT, Proficiency testingQCBP, Quality control base poolQCH, Quality control high sampleQCL, Quality control low sampleQCM, Quality control medium sampleRFU, Relative fluorescence unitsrhGALC, Recombinant human galactocerebrosidaserhβ-gal, Recombinant human β-galactosidase

Identifiers

PMID31720353
PMCPMC6838535
OpenAlexW2980829227

What OpenQuestion holds

Textmetadata
LicenceCC BY-NC-ND
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.