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The effects of 17β-estradiol (E2) or estradiol benzoate (EB) on PGF2α release were studied in bred-non-pregnant and pregnant Nelore beef heifers. The day of timed artificial insemination (TAI) was designated day 0 (D0), and a single treatment was given on D14. All heifers also received an intravaginal P4 device on D14, and were randomly assigned to three groups: Control (C, P4 device only, n = 12); E2 (1 mg E2 + 9 mg P4, n = 10); or EB (1 mg, n = 10). Blood samples were collected hourly for 8 hours after treatment (Hours 0-8) to measure plasma concentrations (pg/mL) of a PGF2α metabolite (PGFM). The P4 device was removed on D22 and pregnancy was diagnosed on D28. Pregnancy rate was not different among groups (C, n = 7/12; E2, n = 5/10; EB, n = 5/10). More (P0.05) heifers had a CV-identified prominent PGFM pulse (peak of100 pg/mL) in E2 group (6/10) than in EB (1/10) and C (0/12) groups. Hourly concentration of PGFM for Hours 0 to 8 showed significant effects of group and hour and an interaction of group by hour but did not show an interaction of group or hour with pregnancy status. In preliminary post-hoc analyses, PGFM concentrations during Hours 0 to 8 and pulse characteristics were analyzed within each pregnancy status. For the non-pregnant heifers, a group-by-hour interaction was detected tentatively indicating an increase (P0.005) in PGFM concentrations in E2 group from Hours 4 to 6 and in EB group at Hours 5 and 6. Maximum PGFM concentration during Hours 0 to 8 did not differ (P0.1) between E2 (124 ± 23) and EB (110 ± 30) groups, but was greater (P0.05) in each group than in C (32 ± 3). Furthermore, PGFM concentrations of pulses at the peak, amplitude, and area under pulse curve (pg/mL/h) were greater (P0.05) in E2 group than in C group whereas the EB group did not differ (P0.1) from the other groups. For pregnant heifers, no effects of group, hour, or their interaction were detected in PGFM concentrations during the hourly sessions, except that maximum PGFM concentration was greater (P0.05) in E2 than in EB and C groups. In addition, the number of prominent pulses was greater in E2 group than in Control or EB groups. In conclusion, PGFM increased earlier and in greater concentration combined for bred-non-pregnant and pregnant heifers treated 14 days after TAI with 1 mg E2 plus 9 mg P4 than with 1 mg EB. Tentatively, a positive effect for each of E2 and EB on PGFM concentrations was attenuated in pregnant heifers.

Inflammation causes increases in the level of matrix metalloproteinases (MMPs), which, in central nervous system (CNS), are associated with neuroinflammation and disruption of blood-brain barrier. Analysis of cerebrospinal fluid (CSF) is pivotal for detecting diseases in CNS and, although a specific diagnosis may not be achieved, this analysis is helpful to confirm the diagnosis or to rule out relevant differential diagnoses. This study examined the levels of MMP-2 and MMP-9 in the CSF of dogs using gelatin zymography to verify possible alterations in these enzymes during natural systemic infection with Leishmania chagasi. Latent and active forms of MMP-2 were detected in some dogs of both groups, with high levels in the control group. In contrast, latent and active forms of MMP-9 were detected only in some animals with leishmaniasis. These results clearly demonstrate that MMP-9 is elevated in CSF of dogs with visceral leishmaniasis (VL). Although these results are preliminary, they suggest that MMP-9 might play a role in disruption of blood-brain barrier and/or blood-CSF barrier. While the presence of MMPs in CSF is not a condition exclusive to VL, their presence and persistence in CSF supports the hypothesis of an inflammatory state within CNS of dogs with VL.