14C-propionate incorporation assay by rapid filtration in multiwell plates.
BACKGROUND
Methylmalonic aciduria (MMA) is divided into two groups according to cobalamin dependency, and this classification is important for treatment. Unfortunately, there has been no rapid and reliable method for the evaluation of cobalamin dependency.


METHODS
[14C]-propionate incorporation into intact cells in the presence of either media alone or media containing various amounts of cobalamin was measured using a 96-well filtration plate and vacuum manifold. Incorporation of radioactivity was measured by direct microplate scintillation.


RESULTS
Using peripheral white blood cells from normal individuals, we obtained a linear relationship between the rate of 14C-propionate incorporation and the number of cells over a broad range (10,000 to 100,000 cells/well). 14C-propionate incorporation in cells from eight patients was 1% to 13% of parallel controls.


CONCLUSIONS
In this report, we describe a rapid, sensitive and reliable method for evaluating the cobalamin dependency of methylmalonic aciduria.
Kakinuma
Hiroaki
H
Department of Pediatrics, Kanazawa Medical University, 1-1 Daigaku, Uchinada, Ishikawa 920-0293, Japan. p-kaki@kanazawa-med.ac.jp
Kobayashi
Azusa
A
Takahashi
Hiroaki
H
D017668:Age of Onset; D002250:Carbon Radioisotopes; D002675:Child, Preschool; D005260:Female; D005374:Filtration / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D007958:Leukocyte Count; D007962:Leukocytes / Q000166:cytology / Q000378:metabolism*; D008297:Male; D008661:Metabolism, Inborn Errors / Q000378:metabolism; D008764:Methylmalonic Acid / Q000378:metabolism; D011422:Propionates / Q000378:metabolism*; D012680:Sensitivity and Specificity; D014805:Vitamin B 12 / Q000378:metabolism
D002250:Carbon Radioisotopes; D011422:Propionates; D008764:Methylmalonic Acid; D014805:Vitamin B 12