A method to estimate probability of disease and vaccine efficacy from clinical trial immunogenicity data.

Vaccine efficacy is often assessed by counting disease cases in a clinical trial. A new quantitative framework proposed here ("PoDBAY," Probability of Disease Bayesian Analysis), estimates vaccine efficacy (and confidence interval) using immune response biomarker data collected shortly after vaccination. Given a biomarker associated with protection, PoDBAY describes the relationship between biomarker and probability of disease as a sigmoid probability of disease ("PoD") curve.

Cryopreservation in different concentrations of glycerol alters boar sperm and their membranes.

To test the hypothesis that glycerol would concomitantly affect sperm membrane structure and the function of the intact cells, boar semen (4 ejaculates from 4 boars) was cryopreserved in an egg yolk extender with 0%, 2%, 4%, or 8% glycerol in 0.5-mL straws using previously derived optimal cooling and thawing rates. Increasing glycerol concentrations increased spermatozoal progressive motility immediately after thawing and after 2 hours at 43 degrees C, but decreased the percentage of sperm with normal acrosomal morphology.

Storage of boar semen.

The problems, aspects and methods of liquid storage and freeze-thawing of boar semen are discussed and a review is given on examination of spermatozoa by the recent fluorescent staining methods.

Behaviour of blastomere nuclei fused to mouse oocytes is affected by oocyte enucleation and age.

The influence of oocyte age and presence of oocyte meiotic apparatus on the behaviour of introduced blastomere nuclei was evaluated. Blastomeres from 4-cell mouse embryos were fused to intact (metaphase II) oocytes, demi-oocytes (nucleate) or cytoplast (anucleate). Fusion and simultaneous activation of the recipient oocytes were accomplished by a single electrical pulse at 20 or 24 h post human chorionic gonadotrophin (hCG) administration.