Tina Lubrano

Separation and quantitation of lactic dehydrogenase isoenzymes by disc electrophoresis

Abstract The disc electrophoresis method of Davis (16) does not permit the separation of all 5 isoenzymes of LDH. The method was modified by omitting the stacking and sample gels, and substituting 40% sucrose solution. All 5 isoenzyme fractions then migrate into the separating gel. The material staining at the surface of the separating gel is shown to be “nothing” dehydrogenase. By accurately marking the distance the albumin-dye or the dye front is to migrate, excellent reproducibility of the isoenzyme separation can be achieved. The separations are such that there is no doubt as to the identification of the individual bands, and quantitation can readily be achieved.

Disc electrophoresis of lactate dehydrogenase isoenzymes

Abstract The original method of disc electrophoresis permitted the localization of only 4 of the 5 lactate dehydrogenase isoenzymes. Conjecture as to the location of one of these is now settled in that it is demonstrated that the lactate dehydrogenase-5 does not migrate through the stacking gel. This was shown for human serum and liver. All 5 isoenzymes migrate into the separating gel by our earlier method. To obtain desirable separations of these for quantitation, it is necessary to use an upper gel of the same composition as the separating gel, to control the geometry of the gels, and to apply an optimal amount of sucrose with the sample.

Subcellular distribution of hypothalamic prolactin-like immunoreactivity

Prompted by interest in immunohistochemical reports of prolactin-like immunoreactivity (PLI) in the rat hypothalamus, we investigated and have reported that an immunoreactive and bioactive prolactin-like material can be extracted from the rat hypothalamus. In the present communication the subcellular distribution of this protein is reported. Using a sensitive and specific radioimmunoassay for rat prolactin and a standardized procedure for subcellular fractionation of neuronal tissue, we have found that 90% of hypothalamic PLI is particulate-bound with only 10% remaining in the S4 or cytosolic fraction. Almost 80% of the particulate-bound PLI is found in the P2 fraction containing myelin, synaptosomes and mitochondria. When P2 is further fractioned on a discontinuous sucrose density gradient, approximately 66% of the P2-associated PLI was found in subfractions rich in synaptosomes and poor in myelin and mitochondria. Such findings support the probability that hypothalamic PLI functions trans-synaptically as a neuromodulator in the brain.

Hemoglobin and haptoglobin determination by disc electrophoresis

Summary 1. An acrylamide disc electrophoretic method is described for separation of hemoglobins with direct quantitation by densitometry; the method is rapid, accurate, and convenient. 2. By this method, measurement of hemoglobin A 2 in 70 normal subjects gave a mean of 2.96%, range 2.1–3.9%. Twenty-one subjects with β -thalassemia trait gave a mean of 6.32%, range 4.4–8.4%. 3. Hemoglobin F can be separated and quantitated by densitometry when present as more than 10% of the total. By this method, values for hemoglobin F are higher than those obtained by alkaline denaturation. 4. The method also allows convenient determination of haptoglobin types and semi-quantitation of serum haptoglobin level.

A family segregating for E1j and E1k at cholinesterase locus 1.

A family segregating for the A, J, and K alleles at cholinesterase locus 1 is described. Several further examples of the AJ and AK phenotypes occur in this family, and one member of the family, by genetic analysis, is phenotype JK. In relation to possible succinylcholine apnoea, phenotypes AJ, AK, and JK should all be considered vulnerable.

Comparison of an electrophoretic and a chemical method for the estimation of serum lactate dehydrogenase isoenzymes

Summary 1. 2. For many clinical purposes, the chemical procedure will give results as useful as those obtained by electrophoretic fractionation, while being both simple and rapid.