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Biomedical subjects

C A Alper

Publications and source records attributed to C A Alper.

At least 199 records · Page 11Linked to original sources
PubMed1972

Inactivator of the third component of complement as an inhibitor in the properdin pathway.

Evidence has been obtained that a single protein, known to modulate classical complement activation, also acts as an inhibitor in the properdin or alternate complement pathway. A highly purified inactivator of the third component of complement (C3) from human serum inhibited the proteolysis of Factor B in the properdin system (glycine-rich beta-glycoprotein) by glycine-rich beta-glycoproteinase. The inhibition was by the enzymatic destruction of glycine-rich beta-glycoproteinase activity. The major fragment of C3, C3b, which is the only known substrate of the C3 inactivator, blocked the destruction of glycine-rich beta-glycoproteinase by the C3 inactivator. Thus, in its inhibition of the porperdin pathway, the C3 inactivator destroys both the active form of glycine-rich beta-glycoproteinase and a protein involved in the conversion of the zymogen form of this enzyme (proglycine-rich beta-glycoproteinase) to its active form. The increased susceptibility to infections in a patient homozygous for deficiency of the C3 inactivator demonstrates the biologic significance of this protein.

Adult↗
PubMed1972

Genetic polymorphism in human glycine-rich beta-glycoprotein.

Extensive polymorphism of glycine-rich beta-glycoprotein (GBG) was found in human sera. In all instances, GBG consisted of at least five components on electrophoresis. Patterns were such that they provided evidence for four alleles (at a locus designated Gb) which were expressed as autosomal codominant traits. Gb(S) and Gb(F) were found in all populations but with different frequencies, Gb(F1) was found in Negroes, and Gb(S1) was found in Caucasians. From electrophoretic studies of GBG, evidence was obtained that suggested that the GBG molecule was a tetramer consisting of A and B subunits in a proportion of about 1.6:1. The genetically controlled differences in GBG embodied in the Gb system indicated the presence of a third moiety of the molecule (C), possibly a polypeptide subunit. Electrophoretic studies of fragments from defined types of GBG suggested that GBG cleavage induced by complement or properdin activation in serum occurred through this C moiety, since two variants were detectable in one fragment and two were found in the other fragment. On comparison of fetal-maternal Gb types, approximately one-half the pairs showed differences. This indicated that GBG did not cross the placental barrier.

Epitopes↗
PubMed1972

Study of four new kindreds with inherited thyroxine-binding globulin abnormalities. Possible mutations of a single gene locus.

Five families with inherited thyroxine-binding globulin (TBG) abnormalities were studied. On the basis of serum thyroxine (T(4))- binding capacity of TBG in affected males, three family types were identified: TBG deficiency, low TBG, and high TBG capacity. In all families evidence for X-linked inheritance was obtained and in one family all criteria establishing this mode of inheritance were met. Only females were heterozygous, exhibiting values intermediate between affected males and normals. Overlap in heterozygotes was most commonly encountered in families with low TBG. QUANTITATIVE VARIATION IN THE SERUM CONCENTRATION OF FUNCTIONALLY NORMAL TBG WAS DEMONSTRATED BY: (a) failure of serum from TBG-deficient subjects to react with anti-TBG antibodies; (b) normal kinetics of T(4) and triiodothyronine-binding to TBG in sera from subjects with low TBG and high TBG capacity; (c) concordance of estimates of TBG concentration by T(4) saturation and by immunological methods; and (d) normal rate of heat inactivation of TBG. No abnormalities in serum transport of cortisol, testosterone, aldosterone, or thyroxine bound to prealbumin could be detected. These observations suggest that all the TBG abnormalities thus far observed reflect mutations at a single X-linked locus involved in the control of TBG synthesis.

Adolescent↗
PubMed1971

C1 inhibitor: evidence for decreased hepatic synthesis in hereditary angioneurotic edema.

Although the Cl inhibitor was detected in 5 to 10 percent of normal hepatic parenchymal cells by means of the immunofluorescent technique, none was seen in liver biopsies from two individuals with hereditary angioneurotic edema having low concentrations of Cl inhibitor in the serum. In contrast, the percentages of cells which reacted with fluorescent antiserums to C4 and transferrin were normal. These data suggest that in most subjects with hereditary angioneurotic edema, there is decreased synthesis of the C1 inhibitor but normal synthesis of C4, and that the disease results from this biosynthetic error.

Adult↗
PubMed1971

Studies of a hypomorphic variant of human C3.

A hypomorphic electrophoretic variant of C3 with the mobility of C3 F was found in the serum of a healthy man, his mother, and one of his two sons. Serum C3 concentrations were normal in these subjects as were hemolytic complement levels. Metabolic studies with radiolabeled purified C3 FF and C3 SS in the propositus suggested, but did not prove, that the variant C3 F gene was hyposynthetic. The designation C3 f was therefore proposed for this allele.

Alleles↗
PubMed1971

Genetically determined heterogeneity of the C1 esterase inhibitor in patients with hereditary angioneurotic edema.

Normal human serum contains 18 +/-5 mg/100 ml of C1 esterase inhibitor (alpha-2 neuraminoglycoprotein) as estimated by immunochemical means. Of 118 patients with hereditary angioneurotic edema, the sera of 80, from 42 kindred, contained a mean concentration of 3.15 mg/100 ml or 17.5% of normal. The mean serum concentration in 35 patients in 7 other kindred was 20 mg/100 ml or 111% of normal, and 3 patients in another kindred contained over 80 mg/100 ml or greater than 400% of normal. The nonfunctional inhibitors in patients' sera of these eight kindred were identical with normal C1 esterase inhibitor by Ouchterlony analysis, but they were different from normal and from each other with respect to their electrophoretic mobility, their capacity to bind C1 esterase, and their ability to inhibit esterolysis of N-acetyl-tyrosine-ethylester.

Acetates↗