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Biomedical subjects

A D Merritt

Publications and source records attributed to A D Merritt.

At least 37 records · Page 2Linked to original sources
PubMed1978

Human pancreatic alpha-amylase: phenotypic codominance and new electrophoretic variants.

The genetic heterogeneity of human pancreatic alpha-amylase (alpha-1,4-glucan 4-glucanohydrolase, E.C. 3.2.1.1) has been better defined through the development of an asparagine buffered electrophoretic gel system. Three alleles had been identified for the pancreatic amylase locus, AMY2, with two variant alleles as autosomal dominant traits on Tris HCl buffered sheet gels. The asparagine buffered sheet gel now allows the differentiation of the genotypes AMY2B/AMY2B,AMY2B/AMY2A, and AMY2B/AMY2C, thus classifying these three alleles as codominants. Asparagine buffered polyacrylamide gels and thin layer polyacrylamide isoelectric focusing aided in the identification of three new pancreatic amylase variants: AMY2D,AMY2E, and AMY2F. AMY2E has been identified only in AMY2B and AMY2E individuals. This allele is proposed as a quantitative activity variant with essentially the same electrophoretic mobility as AMY2A. The other new autosomal variants have each been identified in single white families. AMY2D is dominant and AMY2F is a codominant trait as shown on thin layer polyacrylamide isoelectric focusing gels.

Amylases↗
PubMed1976

Differential expression of salivary (Amy1) and pancreatic (Amy2) human amylase loci in prenatal and postnatal development.

The age-dependent development of alpha-amylase expression in utero and during the first two years of life is reported. Separation of salivary and pancreatic amylase isozymes in a discontinuous buffered sheet polyacrylamide electrophoretic system, with subsequent densitometry, provides a reliable semiquantitative method of estimating the proportions of salivary and pancreatic amylases in urine and amniotic fluid samples. In the newborn the predominant amylase isozymes seen in the urine are of salivary origin. As the child ages the level of amylase in the urine rises and an increase in the proportion of pancreatic amylase isozymes occurs. Amniotic fluids of late first and early second trimester pregnancies contain salivary isozymes. None of the amniotic fluid samples examined has pancreatic amylase isozymes. These data reflect a differential development of the expression of the two amylase approaches adult levels by 16 months of age. Conversely, the salivary (Amy1) locus is expressed as early as 18 weeks of gestation and remains relatively constant with but a small increase in salivary amylase (units/ml) activity during early development, as the total amylase activity approaches adult values.

Age Factors↗