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R C Harruff

Publications and source records attributed to R C Harruff.

30 records · Page 2Linked to original sources
PubMed1983

Potential errors in the laboratory diagnosis of paroxysmal nocturnal hemoglobinuria.

In a retrospective study of laboratory tests for paroxysmal nocturnal hemoglobinuria (PNH), the red blood cells of several patients gave conflicting results when different testing procedures were used. To resolve these discrepancies, an examination of the various procedures was undertaken, using sulfhydryl reagent-treated red blood cells as model PNH cells. Rabbit antiserum to human red blood cells was used to sensitize erythrocytes for specific antibody-dependent complement lysis sensitivity tests. Acidified serum and inulin were used in fluid-phase complement activation tests. For the general laboratory, a modification of the sucrose lysis test is described, which can give the relative complement sensitivity and size of an abnormal subpopulation of red blood cells. Considering the results of our patients and the reports in the literature of the association of PNH with a variety of lymphoproliferative and myeloproliferative disorders, it is stressed that testing procedures for PNH be controlled more carefully for a better understanding of the nature of the membrane defect.

Complement System Proteins↗
PubMed1980

Glioblastoma multiforme with tuberous sclerosis. Report of a case.

Gliomas of the CNS associated with tuberous sclerosis have been well documented; malignant degeneration to glioblastoma multiforme, however, is rare. We studied a 17-year-old boy with stigmata of tuberous sclerosis and a cerebral glioblastoma multiforme. The rarity of this occurrence suggests that neoplasms arising from hamartomas may behave differently than those CNS tumors that arise apparently de novo.

Adolescent↗
PubMed1975

Factors contributing to the inhibition of aspartate aminotransferase by dicarboxylic acids.

At pH 8.0 aspartate aminotransferase (L-aspartate:2-oxoglutarate aminotransferase, EC 2.6.1.1) reacts with the modified substrate, erythro-beta-hydroxy-L-aspartate, to form a mixture of enzyme-substrate complexes absorbing at 492 nm. A variety of dicarboxylic acids were studied spectrophotometrically as competitive inhibitors of this reaction. All of the inhibitory dicarboxylic acids form a complex with the enzyme, absorbing at 362 nm. In addition, some of the dicarboxylic acids form a protonated complex absorbing at about 435 nm. This complex, which is the conjugate acid of that absorbing at 362 nm, is formed only by those dicarboxylic acids which can assume a configuration in which the two carboxyl groups are positioned as in maleic acid. Bulky substituents, such as aromatic rings or even methyl groups, prevent the formation of the protonated complex, presumably because of steric restrictions at the active site. Substitution of the central carbon atom of glutaric acid by heteroatoms of increasing charge density results in a progressive decrease in inhibitory effectiveness, at pH 8, primarily due to a loss of this pH-dependent stabilization of the enzyme-dicarboxylic acid complex. Acids with an aromatic ring are among the most potent dicarboxylic acid inhibitors of this enzyme in spite of the fact that they do not undergo the pH-dependent stabilization of their enzyme complexes. From these observations it was concluded that the affinity of aspartate aminotransferase for dicarboxylic acids is determined as much by the mechanism of binding as by the solvation and steric effects.

Animals↗