Total lactate dehydrogenase-specific activity and concentration of isoenzymes were determined on extracts of rat uterus at different stages of pregnancy, during the oestrous cycle and after ovariectomy.Total enzymatic activity increased during pregnancy. The rise was evident by the 5th day and continued steadily until the 14th day, when it attained maximal values. These high values were maintained up to the end of pregnancy and fell to the level of controls 4 days after parturition.The changes in enzyme activity were entirely due to variations in the amount of Isoenzymes 5 (A4) and 4 (A3B1). The other three molecular forms were not modified Total specific activity and Isoenzymes 5 and 4 were diminished 20 days after ovariectomy.
Background: The pathogenesis of Hypoplastic Left Heart Syndrome (HLHS), a congenital heart disease with significant morbidity and mortality, remains unknown. We previously proposed a hypothesis wherein HLHS represents a type of rheumatic heart disease in the fetus; trans-placental passage of maternal anti-strep or anti-cardiac myosin (CM) antibodies are postulated to play a key role in the pathogenesis of disease. This is a first report of an animal model that we have developed to assess our hypothesis. Methods: Female Lewis rats (∼ 8 weeks old) were immunized with either streptococcal antigen M type 5 S. pyogenes (PepM5; n=6), rat CM (n=8) or saline (controls; n=5) with three booster injections administered at 2-week intervals. Serum titers of acquired PepM5 or CM antibodies were determined by ELISA assays every 7–14 days. No boosters were administered during gestation. Trans-uterine echocardiography was performed near term (E19-21) to determine fetal number and viability then cesarean section was performed under anesthesia to deliver the progeny. Maternal and fetal serum and hearts were harvested for analysis. Results: All rats immunized with PepM5 had elevated serum anti-PepM5 antibody titers (>1:12800) and two of these animals also had elevated anti-CM titers (1:800). The offspring of these PepM5 immunized animals had elevated anti-PepM5 antibody titers (≥1:6400), but no CM elevation. Rats immunized with CM had a variable response ranging from anti-CM titers of 1:1600 to >1:12800; there were two non-responders. Their fetuses had anti-CM titers that ranged from 1:100 to 1:800. None of the controls had detectable serum titers. Fetal CM titers of ≥1:200 correlate with maternal peak CM titers of ≥1:6400 and/or maternal harvest titers of ≥1:800. Thus far, 6 of the CM treated fetuses have evidence of left-sided morphologic abnormalities along a variable spectrum; all of these fetuses had CM titers of ≥1:200. Conclusion: We have documented maternal antibody response and trans-placental antibody transfer from maternal rats immunized with CM or PepM5 prior to pregnancy. Anti-CM antibody does not cross the placental as readily as PepM5. Preliminary histologic findings demonstrate probable HLHS phenotype, which appears to correlate with fetal antibody titer.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.