Modulation of blood pressure in the Dahl SS/jr rat by embryo transfer.

Gestational hypertension and malnutrition are associated with hypertension and ischemic heart disease in the adult human. The impact of the gestational environment on the adult blood pressure in two well-characterized genetically homogeneous rat strains, the hypertensive SS/jr and normotensive SR/jr, was studied by cross-fostering within 6 hours of birth and by embryo transplantation with the recipient dam nursing the transplanted pups. Systolic blood pressure (BP) was measured by tail-cuff plethysmography twice a week after the age of 7 weeks. The lactational environment (cross-fostering) had no effect on blood pressure. Embryo transfer between like strains had no effect on the development of hypertension, nor did the BP of R transferred to S (RetS) differ from that of normal R or RetR. At 7 weeks of age, the BP of SetR was significantly lower than that of S or SetS (P<.01) and was similar to that of RetR and R. With age, the blood pressures of the S, SetS and SetR increased at approximately the same rate but from a significantly different baseline. Salt-sensitivity in the S and resistance in the R were not altered. The protective effect of the R gestational environment on SetR female BP was abrogated during whelping and lactation. Embryo transfer and cross-fostering did not alter the weight of rats older than 7 weeks. Because the BP of the R dams were significantly lower than that of the S dams, these studies do not distinguish between the effects of the R dams' lower blood pressure per se and hormonal influences of the R uterus on the S blood pressure phenotype.

Simple sensitive solid-phase extraction of paraquat from plasma using cyanopropyl columns.

We report an inexpensive, sensitive paraquat quantitation method which is simple to perform. First, 5 mL of blanks, standards, or patient plasma are applied to 1-mL cyanopropyl extraction columns equipped with 15-mL reservoirs. The samples are drawn through the columns under vacuum, followed by a rinse with 15-20 mL of 0.1M NH4OH. Paraquat is eluted with 0.8 mL 0.1M HCl, which is then neutralized with 25 microL concentrated NH4OH. Sodium dithionite reagent (0.23M in 4M NaOH) is added (100 microL) and the color produced is measured by absorbance difference (A395-A460). The assay is linear up to at least 4.35 microM paraquat. The lower limit of quantitation is 0.23 microM. Lipemic and icteric sera do not affect the method, but easily visible hemolysis elevates the concentrations measured by up to 0.7 microM, independent of paraquat concentration. Equimolar amounts of diquat with paraquat, at paraquat concentrations from 0.4 to 4.0 microM, elevate apparent paraquat concentrations by 0.08-0.28 microM. At 0.632, 1.92, and 4.06 microM paraquat, within-run coefficients of variation (CVs) were 6.27, 7.23, and 2.14%, and between-run CVs were 6.82, 8.42, and 4.43%, respectively.