Effects of estradiol treatments on PGF2α release in beef heifers submitted to estrous resynchronization 14 days after timed-AI.

The effects of 17ß-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 (P < 0.05) heifers had a CV-identified prominent PGFM pulse (peak of > 100 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 (P < 0.005) 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 (P > 0.1) between E2 (124 ± 23) and EB (110 ± 30) groups, but was greater (P < 0.05) 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 (P < 0.05) in E2 group than in C group whereas the EB group did not differ (P > 0.1) 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 (P < 0.05) 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.

Type I interferon receptors and interferon-τ-stimulated genes in peripheral blood mononuclear cells and polymorphonuclear leucocytes during early pregnancy in beef heifers.

This study characterised the expression of interferon (IFN)-τ-stimulated genes (ISGs) and Type I IFN receptors in circulating polymorphonuclear cells (PMNs) of beef heifers and compared it with expression in peripheral blood mononuclear cells (PBMCs) up to Day 20 of gestation. Nelore heifers (n=26) were subjected to fixed-time AI (FTAI) on Day 0. PMNs and PBMCs were isolated on Days 0, 10, 14, 16, 18 and 20 after FTAI. The abundance of target transcripts (ubiquitin-like protein (ISG15), 2'-5'-oligoadenylate synthetase 1 (OAS1), myxovirus resistance 1 (MX1), myxovirus resistance 2 (MX2), IFN receptor I (IFNAR1) and IFN receptor 2 (IFNAR2)) was determined using real-time quantitative polymerase chain reaction and compared between pregnant (n=8) and non-pregnant (n=9) females. In both PBMCs and PMNs, ISG15 and OAS1 expression was greater in pregnant than non-pregnant heifers on Days 18 and 20. There were no significant differences in the expression of ISGs between PBMCs and PMNs. A time effect on expression was found for IFNAR1 in PBMCs and IFNAR2 in PMNs, with decreased expression of both genes on Days 18 and 20. When the expression of these genes was compared between cell types only in pregnant heifers, IFNAR2 expression in PMNs had an earlier decrease when compared to its expression in PBMCs, starting from Day 18. In conclusion, PMNs do not respond earlier to the conceptus stimulus, and ISG15 and OAS1 expression in both PMNs and PBMCs can be used as a suitable marker for pregnancy diagnosis on Days 18 and 20. In addition, gestational status did not affect IFNAR1 and IFNAR2 expression, but IFNAR2 showed a distinct response between PMNs and PBMCs of pregnant heifers.

Increased pregnancy rate in beef heifers resynchronized with estradiol at 14 days after TAI.

We aimed to evaluate the treatment with estradiol benzoate (EB) or 17ß-estradiol (E2) associated with progesterone (P4) for resynchronization of ovulation 14 days after timed artificial insemination (TAI). In Experiment 1 (Exp. 1), Nelore heifers were submitted to TAI (D0). On D14, the animals received an intravaginal P4 device and were randomly assigned to one of three groups: control (no treatment; n = 17); EB (1  mg EB; n = 17); and E2+P4 (1 mg E2 + 9 mg P4; n = 18). Ultrasonography evaluations were performed daily from D14 to D22 to map follicular and luteal dynamics. On D22, the P4 devices were removed and non-pregnant (NP) animals were determined using corpus luteum blood flow Doppler ultrasonography. In Exp. 2, 1295 beef heifers were resynchronized and randomly allocated to the same experimental groups as described in Exp. 1. On D22, the largest follicle (LF) was measured in NP and a second TAI was performed on D24. In a subset of heifers (n = 337), an estrus detection patch was used between D22 and D24 to monitor estrus expression and the LF was measured at D24. Confirmatory diagnosis of pregnancy was performed between D37-67 and D43-67 after first and second TAI, respectively. In Exp 1, the proportion of heifers with a synchronized follicular wave emergence (from 3 to 5 days after treatment) was greater (P < 0.05) in the EB group (93.8%) than in the control (62.5%) and E2+P4 (64.7%) groups. Structural luteolysis occurred earlier (P < 0.05) in the EB and E2+P4 groups than in the controls. The pregnancy rate after first TAI did not differ (P > 0.1) among the groups at D22 and at confirmatory diagnosis in both experiments. In Exp 2, the potential pregnancy loss between D22 and D37-67 was similar (P > 0.1) in the control (19% [36/185]), EB (15% [28/182]) and E2+P4 (15% [28/184]) groups. The LF diameter (mm) on D22 was greater (P < 0.05) in the control group (11.9 ± 0.1) than in EB (11.3 ± 0.1) and E2+P4 (11.5 ± 0.1). No difference (P > 0.1) was observed in the proportion of heifers detected in estrus, but LF growth rate (mm/day) between D22 and D24 was greater (P < 0.05) in EB group (0.9 ± 0.08) than in control (0.6 ± 0.07) and E2+P4 (0.7 ± 0.09) groups. The pregnancy rate for the second TAI was greater (P < 0.05) in the EB group (47% [94/200]) than in the control (37% [76/203]), but did not differ (P > 0.1) from the E2+P4 group (43% [93/214]). In conclusion, the treatment with 1 mg EB or 1 mg E2 + 9 mg P4 at 14 days post-TAI anticipates luteolysis in NP heifers but does not compromise pregnancy. The EB treatment induces a new synchronized follicle wave emergence and increases the pregnancy rate of resynchronized NP heifers.

Evaluation of positive and false-positive results in syphilis screening of blood donors in Rio de Janeiro, Brazil.

OBJECTIVES: We propose to analyse the positive and false-positive results of treponemal and nontreponemal tests in blood donors from Brazil and to evaluate possible factors associated with the results of treponemal tests. BACKGROUND: Treponemal tests have been used widely for syphilis screening in blood banks. The introduction of these tests in donor screening has caused an impact and a loss of donors who need to be assessed. METHODS: This was a retrospective cross-sectional study of syphilis screening and confirmatory test results of blood donors that were obtained before and after adopting a chemiluminescent immunoassay (CLIA). A comparative analysis was performed using a second sample drawn from positive donors. The possible factors associated with CLIA-positive or CLIA-false-positive results were investigated in a subgroup. Statistical tests were used to compare the proportions and adjusted estimates of association. RESULTS: The reactivity rate increased from 1·01% (N = 28 158) to 2·66% (N = 25 577) after introducing the new test. Among Venereal Disease Research Laboratory (VDRL)- and CLIA-confirmed results, the false-positive rates were 40·5% (N = 180) and 37·4% (N = 359), respectively (P = 0·5266). Older donors (OR = 1·04; P = 0·0010) and donors with lower education levels (OR = 6·59; P = 0·0029) were associated with a higher risk of positivity for syphilis. CONCLUSIONS: CLIA represents an improvement in blood bank serological screening. However, its use in a healthy population appears to result in high rates of false positives. Identifying which characteristics can predict false positives, however, remains a challenge.

Determinacao quantitativa das imunoglobulinas IgA e IgM, no sangue do cordao umbilical, pela tecnica de dupla difusao em gel de agar. / Quantitative determination of IgA and IgM immunoglobulins, in umbilical cord blood, by double agar gel diffusion technique

Visando encontrar tecnica simples e barata que pudesse ser aplicada na pesquisa e titulacao das imunoglobulinas IgA e IgM no sangue do cordao umbilical de todos os recem-nacidos foi estudada a imunodifusao dupla quantitativa, comparando-a com a imunodifusao radial.Inicialmente, 249 soros de recem-nascidos foram estudados, para IgA e IgM, pela tecnica de imunodifusao dupla quantitativa.Em seguida, a comparacao entre esta tecnica e a imunodifusao radial foi realizada em 20 soros para IgM e 33 para IgA. Foram estudados,ainda 10 soros de casos reconhecidamente patologicos, comparativamente, pelas duas tecnicas. A tecnica de dupla difusao em gel de agar revelou a presenca de IgM no sangue do cordao umbilical em mais de 80% de recem-nascidos normais . A IgA foi relevada em cerca de 15% dos casos. Houve correlacao entre os valores quantitativos determinados pelas tecnicas de dupla difusao e de difusao radial, tanto para IgA, quanto para IgM. A tecnica de dupla difusao qualitativa em gel de agar, utilizando soro de cordao umbilical, sem diluir para IgA e diluido a 1/8 para IgM, podera ser empregada com a finalidade de revelar infeccao fetal, em todos os recem-nascidos, dado seu baixo custo e facilidade de execucao