PubMed Health⌕ Search

Biomedical subjects

J C Dominguez

Publications and source records attributed to J C Dominguez.

4 recordsLinked to original sources
PubMed2007

Effect of cloprostenol treatment at artificial insemination on sow fertility.

In two experiments, we examined the effect of administration of cloprostenol at artificial insemination on fertility of multiparous sows. Lactation length was 21 days and only sows exhibiting estrus by 7 days after weaning were included. Cloprostenol was administered by IM injection (175 microg; n=126) or supplemented in the semen dose (525 microg; n=129). Control sows (n=130) received no hormone. In either experiment, there was no effect of any treatment on subsequent litter sizes. In experiment 1, there was no effect of treatment on farrowing rate, but in experiment 2, farrowing rate was higher (p < 0.05) in sows receiving cloprostenol by injection. Taken together, these results indicate no consistent effect of cloprostenol administration by intramuscular injection or by inclusion in the semen dose on sow fertility and so its routine use is not warranted.

Animals↗
PubMed1994

Sheep embryo cryopreservation by vitrification and conventional freezing.

The survival of ovine embryos (morulae and blastocysts) either frozen by a conventional method or vitrified was investigated in culture. In Experiment I, embryos were vitrified using a solution containing 25% propylene glycol and 25% glycerol. A group of embryos (simulated control) was processed without freezing to evaluate the toxicity of the vitrification solution. In Experiment II, embryos were exposed to a solution of PBS containing 10% glycerol and 0.25 M sucrose placed horizontally in a programmable freezer. Automatic seeding was applied at -7 degrees C in 2 positions on straws and cooled at -0.3 degrees C/min to -25 degrees C and then stored in liquid nitrogen. In vitro development rates of vitrified embryos were 12% (morulae) and 19% (blastocysts). Simulated embryos showed a higher rate of survival than embryos cryopreserved by vitrification (67 and 63%, morulae and blastocysts respectively). In conventional cooling, the blastocysts showed the highest viability percentage (67%) of all the experimental groups but these values decreased significantly in morulae (31%). Differences in temperature between straws placed in distinct positions in the freezing chamber and thermic deviation were observed when automatic seeding was applied. Embryo viability differed from 51 to 75% according the relative position of the embryos within the chamber. Survival was higher when automatic seeding was applied on the meniscus of the embryo column versus the central point of this column (65 vs 21%). The damage of both cryopreservation methods on zona pellucida integrity (27 and 35% in vitrified and conventionally frozen embryos, respectively) had no effect on the in vitro survival.

Journal Article↗
PubMed1993

Plasminogen-dependent activation of latent transforming growth factor beta (TGF beta) by growing cultures of osteoblast-like cells.

Osteoblasts secrete transforming growth factor beta (TGF beta) as a biologically inert, latent complex that must be dissociated before the growth factor can exert its effects. We have examined the production and proteolytic activation of latent TGF beta (LTGF beta) by clonal UMR 106-01 rat osteosarcoma cells and neonatal mouse calvarial (MC) osteoblast-like cells in vitro. Synthetic bPTH-(1-34) increased the activity of tissue-type (tPA) and urokinase-type (uPA) plasminogen activators (PA) in cell lysates (CL) of UMR 106-01 cells. The concentration of active TGF beta in serum-free CM from cultures treated with bPTH-(1-34) and plasminogen was significantly greater than in CM from untreated controls and cultures treated with either bPTH-(1-34) or plasminogen alone. This effect occurred at concentrations of PTH-(1-34) that increased PA activity and was prevented by aprotinin, an inhibitor of plasmin activity. Treatment with bPTH-(1-34) had no effect on the concentration of TGF beta in acid-activated samples of CM. Functional consequences of proteolytically activated TGF beta was examined in primary cultures of neonatal MC osteoblast-like cells. Human platelet TGF beta 1 caused a dose-dependent increase in the migration of these cells in an in vitro wound healing assay. Cell migration was also stimulated in cultures treated with bPTH-(1-34) and plasminogen together. This effect was blocked by an anti-TGF beta 1 antibody. The results of these studies demonstrate that (1) LTGF beta secreted by osteoblasts in vitro is activated under conditions where the plasmin activity in the cultures is increased, and (2) the TGF beta generated by plasmin-mediated proteolysis is biologically active. We suggest that the local concentration of TGF beta in bone may be controlled by the osteoblast-associated plasminogen activator/plasmin system. Furthermore, since several calciotropic factors influence osteoblast PA activity, this system may have an important role in mediating their anabolic and/or catabolic effects.

Animals↗