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Biomedical subjects

L D Petz

Publications and source records attributed to L D Petz.

At least 109 records · Page 6Linked to original sources
PubMed1969

In vivo metabolism of complement. I. Metabolism of the third component (C'3) in acquired hemolytic anemia.

The in vivo metabolism of purified third component of complement labeled with (125)-iodine (C'3-(125)I) was studied in normal subjects and in patients with acquired hemolytic anemias. 27 such studies were performed; in addition, three studies were performed using C'3i, the biologically inactive reaction product of C'3. In normal subjects the mean fractional catabolic rate of C'3 was 2.12%/hr and the normal range (defined throughout as the mean +/- 2 SD) was from 1.56 to 2.68. The mean percentage of C'3 that was intravascular was 66.6% and the normal range was from 51 to 83. The C'3 synthesis rate averaged 1.16 mg/kg per hr with a normal range of from 0.90 to 1.42. The mean serum concentration of C'3 was 1.43 mg/ml with a normal range of from 1.00 to 1.87. The fractional catabolic rate and synthesis rate of C'3 were at the upper limit of normal or were increased above normal in patients who had warm antibody autoimmune hemolytic anemia with complement on their erythrocytes and in patients with paroxysmal nocturnal hemoglobinuria studied during periods of active hemolysis. An increased C'3 synthesis rate was also found in one patient who was hematologically normal but had an active peptic ulcer and elevated serum concentration of C'3.A normal fractional catabolic rate and C'3 synthesis rate were found in patients with autoimmune hemolytic anemia associated with alpha-methyldopa administration, atypical cold antibody autoimmune hemolytic anemia, and in paroxysmal nocturnal hemoglobinuria during an asymptomatic interval. The three studies with C'3i-(125)I revealed a very rapid removal of the labeled protein from the plasma with less than 10% remaining after 2 hr and with a corresponding increase in urinary excretion rate of the label. The fractional catabolic rate of C'3i averaged 37%/hr. The findings are consistent with the previously elucidated in vitro reaction mechanism of C'3 and strengthen the concept that serum complement participates in immune reactions in vivo.

Adolescent↗
PubMedDate not supplied

The significance of red cell bound complement components in development of standards and quality assurance for the anti-complement components of antiglobulin sera.

Human red blood cells, sensitized with complement in vivo and by a variety of methods in vitro, (e.g. blood group antibody, low ionic strength, alternate pathway), were tested with a battery of anti-complement sera (anti-C3, -C3c, -C3d, -C4, -C4c). Red blood cells could be prepared by relatively simple methods to yield cells sensitized with C3 and C4, C3 but not C4, C4 but no C3, C3d with no C3c and C4d with no C4c. These cells are suitable for standarization and quality assurance of antiglobulin sera (AGS). Anti-C3d is necessary for optimal detection of sensitization of red blood cells by complement in vivo by the direct anti-globulin test (DAT). Anti-C3d may also be optimal for the indirect antiglobulin test (IAT) especially if incubation periods greater than one hour are employed. Potent anti-C4 and anti-C3 antisera made in the authors' laboratory resulted in numerous weakly positive antiglobulin tests when testing red blood cells from refrigerated clots (especially anti-C4) but red blood cells from refrigerated anticoagulated segments gave negative results. When red blood cells were incubated in normal serum at room temperature (as in the room temperature phase of a compatibility test), some positive results were again obtained with the potent anti-C4 and anti-C3 antisera. However, one commercial antiglobulin serum containing anti-complement antibodies that were at least as potent as any other commercial antiglobulin serum gave uniformly negative results under the above conditions. Anti-C4 antibodies may be omitted from anti-globulin sera without decreasing the efficacy of such antisera to be used in compatibility testing. Thus, positive results in the compatibility test due to detection of clinically insignificant cold antibodies in the IAT by the anti-complement antibodies in AGS, may be avoided if anti-C4 is omitted or is in low concentration and if the concentration of anti-C3d is carefully standardized. A higher concentration of anti-C3d could be used for compatibility tests if red blood cells from anticoagulated segments were used instead of those from clots and if a separate tube were used for the IAT at 37 C rather than using one tube for both room temperature and 37 C incubations.

Antibody Specificity↗
PubMedDate not supplied

Autoimmune hemolytic anemia associated with IgG auto anti-N.

A second case of autoimmune hemolytic anemia mediated by an IgG auto Anti-N is described. The patient's red blood cells were sensitized with both IgG and complement. The serum antibody was not inactivated by 2-mercaptoethanol treatment, and reacted by indirect antiglobulin test at 37 C with monospecific anti-IgG. The IgG antibody eluted from the red blood cells and in the serum showed anti-N specificity. The patient was thought to have systemic lupus erythematosus. Following steroid therapy, the hemolytic anemia resolved with disappearance of the anti-N.

Adult↗
PubMedDate not supplied

Clinical significance of the anti-complement component of antiglobulin antisera.

The need for anti-complement (anti-C') activity in antiglobulin antisera (AHG) for the detection of clinically significant antibodies was evaluated during a three-year period. While performing routine compatibility testing using standard blood banking procedures, eight patients were found whose antibodies were detectable primarily or only by AHG containing anti-C' activity; monospecific anti-igG AHG gave weak or negative reactions. Seven of the antibodies were anti-jka or jkb. Two of the anti-jka antibodies were responsible for clinically unsuspected delayed hemolytic transfusion reactions. The anti-jkb antibody resulted in a shortened survival of incompatible 51Cr-labelled red blood cells. The incidence of such "complement-only" Kidd antibodies was 23 percent of all Kidd antibodies found. These data suggest that the omission of anti-C' in AHG in routine compatability testing could result in substantial risk of failure to detect clinically significant antibodies.

Aged↗