Cryopreserved bovine semen is less fertile than fresh semen for reasons that have not been fully elucidated. Cryopreservation is known to disrupt the sperm plasma membrane and it induces premature capacitation of a sperm subpopulation, which may be a result of the increased internal calcium levels after thawing. To test the hypothesis that sperm intracellular calcium level is correlated with in vivo fertility, we used the fluorescent calcium indicator, indo-1, and flow cytometry to assess intracellular calcium levels in frozen-thawed sperm from bulls of varying degrees of fertility. We also tested a second hypothesis that the physiological status of sperm, as assessed by the chlortetracycline (CTC) fluorescent assay, is correlated with fertility. As detected by indo-1 fluorescence, the intracellular calcium level is negatively correlated with bull fertility immediately after thawing (P = .0362; n = 3 ejaculates from each of 10 animals). Moreover, there was a significant difference between the 3 most and least fertile bulls over 4 hours of incubation (P < .05; n = 3 ejaculates per bull). Finally, there was a positive correlation between sperm displaying the CTC acrosome reaction pattern and fertility (P = .0014; n = 3 ejaculates from each of 10 bulls).

Acrosome Reaction↗

PubMedDate not supplied

[Structural study of substituted benzamides with antidopaminergic D-2 activity. Comparison with orthopramides with 5HT-3 antiserotoninergic profile].

Crystallographic results coupled with theoretical calculations, NMR analyses, and molecular graphic design have been used to investigate the three-dimensional structures of different Na(+)-dependent D-2 antagonists. Three putative pharmacophoric elements, a nitrogen lone pair, a phenyl ring, and a carbonyl moiety, are similarly oriented in all these compounds. Moreover, a stereoelectronic model can be deducted from the molecular electrostatic potential maps. Conversely, for Na(+)-independent analogs, the two latter pharmacophoric elements play a subordinate role, but two electron regions are systematically localized on the other side of the molecule. The three pharmacophoric elements of the Na(+)-dependent D-2 antagonists have been identified in the 5HT-3 antiserotoninergic drugs, but only in terms of chemical functions.

Benzamides↗

PubMedDate not supplied

A harlequin baby survives.

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Adult↗

PubMedDate not supplied

Models for intensive care. Small patient big challenge.

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Critical Care↗