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Biomedical subjects

C A Alper

Publications and source records attributed to C A Alper.

At least 217 records · Page 12Linked to original sources
PubMed1970

Studies in vivo and in vitro on an abnormality in the metabolism of C3 in a patient with increased susceptibility to infection.

In a patient with increased susceptibility to infection, lowered serum C3 concentration, and continuously circulating C3b, it was shown that purified (125)I-labeled C3 was converted to labeled C3b shortly after intravenous administration. The fractional catabolic rate of C3 was approximately five times normal at 10% of the plasma pool per hr. The synthesis rate and pool distribution of C3 were normal. Despite this evidence of C3 instability in vivo, no accelerated inactivation of C3 was found in vitro. Similarly, no free proteolytic activity could be detected in the patient's serum, and serum concentrations of known protease inhibitors were normal.Complement-mediated functions, which were markedly deficient in the patient's serum, could be restored partially or completely by the addition of a 5-6S heat-labile beta pseudoglobulin from normal serum. The C3 proinactivator, which has these physicochemical characteristics, was also shown to be either absent or nonfunctional in the patient's serum. An unidentified 6S beta pseudoglobulin to which a monospecific antiserum was available was not detectable in the patient's serum. This last protein appeared not to be a complement component, nor was it the C3 inactivator or proinactivator. Finally, the substance or substances necessary for the conversion of C3b to C3c were missing from the patient's serum. The administration of 500 ml of normal plasma to the patient corrected all of his abnormalities partially or completely for as long as 17 days. The changes in C3 were dramatic; serum concentration rose from 8 to 70 mg/100 ml, and C3b could no longer be detected. A second metabolic study during this normalization period showed a decrease in fractional catabolic rate toward normal. The patient's histamine excretion was constantly elevated but increased further after a warm shower and after receiving normal plasma; at both times he had urticaria. These observations were consistent with the endogenous production of C3a and the resulting histamine release from mast cells. The inactivating mechanism for C3a was apparently intact in the patient's serum. The difference in the electrophoretic mobilities of C3b and C3c was shown as well as the electrophoretic heterogeneity of C3c. Suggestive evidence was also presented that the form of C3 with an activated combining site for red cells, previously postulated by others, is a transient C3 conversion product with an electrophoretic mobility slower than that of C3 on agarose electrophoresis.

Adult↗
PubMed1969

The enhancement of bacterial phagocytosis by serum. The role of complement components and two cofactors.

The role of serum factors in the phagocytosis of pneumococci was studied employing a spectrophotometric assay which measures reduced nitro blue tetrazolium (NBT) dye. Dye reduction occurs within the phagocyte shortly after bacterial ingestion as measured by the phagocytic index technique and by the uptake of (125)I-pneumococci. Bacteria prepared with gammaG antibody were not phagocytosed unless a small volume of fresh normal serum was added. Using fresh sera deficient in single complement components, it was demonstrated that the first four components are necessary for optimal bacterial phagocytosis. When highly purified complement components were added to the antibody-coated pneumococci, enhancement of phagocytosis was achieved only with the sequential addition of C1, C4, C2, and C3. Evidence has been presented that human C3 bound to an immune complex exhibits peptidase activity and that this activity is essential for phagocytosis. A heat-labile, dialyzable serum cofactor which enhances C3 peptidase activity enhanced the phagocytosis of pneumococci prepared with purified complement components. A second phagocytosis-promoting cofactor, which is not a complement component, was found to be a heat-labile, 5-6S, beta pseudoglobulin. This protein may stabilize C3 peptidase activity or inhibit enzymatic inactivation of C3.

Blood Proteins↗
PubMed1969

Genetic polymorphism of rhesus thyroxine-binding prealbumin: evidence for tetrameric structure in primates.

Polymorphism in primate thyroxine-binding prealbumin was investigated with agarose gel electrophoresis at pH 8.6. In the rhesus monkey (Macaca mulatta), three forms of this protein were found in random sera: a single rapidly migrating band similar to that in human and other primate sera, a single slowly migrating band cathodal to rhesus albumin, and a five-banded form, the most rapid and slowest bands of which corresponded to the other two forms. The frequencies of occurrence of these three forms were consistent with the hypotheses that rhesus prealbumin is under the control of two codominant autosomal alleles, PA(F) and PA(S), and that the protein occurs naturally in serum as a tetramer composed of similar subunits.It was possible, by simple mixing in vitro, to produce five-banded prealbumin patterns from rhesus PA SS serum and rhesus PA FF serum, M. arctoides serum, P. hamadryas serum, and human serum. Thyroxine was bound by all the hybrid molecules produced in this fashion.

Alleles↗
PubMed1969

Inherited deficiency of the third component of human complement (C'3).

A kindred has been investigated in which seven individuals were found to have half-normal serum concentrations of the third component of complement (C'3). This partial deficiency was transmitted as an autosomal dominant trait. Affected individuals were entirely healthy. Hemolytic complement titers were slightly reduced but immune adherence titers and reagent titrations of the classical complement components were normal.Examination for C'3 allotypes revealed that all affected individuals had patterns resembling those of homozygotes. Analysis of the inheritance of C'3 structural genes disclosed that the most likely mechanism for partial C'3 deficiency in this family was nonexpression of one allele.

Blood Protein Electrophoresis↗
PubMed1969

Inheritance of human alpha-1-acid glycoprotein (orosomucoid) variants.

Although variants of sialic acid-free alpha(1)-acid glycoprotein have been described in human beings, the mode of inheritance of these types has not been reported previously. With the use of a new technique of immunofixation after agarose gel electrophoresis of neuraminidase-treated whole serum, the present study demonstrates that the types of alpha(1)-acid glycoprotein variants in family members are consistent with inheritance as autosomal traits with codominant expression. Gene frequencies have been determined for several ethnic groups. Of a total of 11 maternal-cord serum pairs, seven were discordant types, indicating that the fetus synthesizes alpha(1)-acid glycoprotein and confirming a previous report that there is no significant transplacental passage of this protein.

Animals↗
PubMed1968

C'3 synthesis in the human fetus and lack of transplacental passage.

Allotypic differences in the third component of complement between mothers and their newborns provided evidence for synthesis of this complement component by the fetus. There was no indication that this protein traversed the placenta. The known low level of C'3 in the neonate was confirmed, and the maternal concentration was found to be significantly elevated.

Beta-Globulins↗