Effect of intravaginal instillation of some non-steroidal oral antifertility agents on pregnancy in rats

A study was conducted of the effect of intravaginal instillation of 3 nonsteroidal oran antifertility agents in pregnant rats. The 3 compounds used were 2-phenyl-3-rho-beta-pyrrolidinoethoxyphenyl-6-methox y benzofuran hydrochoride (DBF), 20 mg/kg; 2-phenyl-3-rho-beta-pyrrolidi noethoxyphenyl-naptha (2:1,b furan (NF), 10 mg/kg; and Centchroman, 1.25 mg/kg. These agents were administered on Day 1 postcoitum at the single-day oral contraceptive dose. Control animals were inserted with a pellet containing only carboxymethyl cellulose. Only Centchroman was 100% effective in preventing pregnancy. Even at half the normal dose, Centchroman was effective. Of the 3 compounds, only Centchroman has an antiprogestational property which may be contributing to Centchroman's high antifertility activity by the vaginal route and may prevent side effects.     

THE INTRINSIC MECHANISM OF CHROMATIN DECONDENSATION AND ITS ACTIVATION IN HUMAN SPERMATOZOA*

In vitro decondensation of human sperm chromatin induced by the activation of an intrinsic mechanism was studied by light microscopy, scanning and transmission electron microscopy. Morphological evidence was provided to support the concept that this mechanism is essential for the chromatin decondensation occurring in vivo. Prostatic zinc is hypothesized to preserve this potential decondensation ability from oxidative destruction, by reversibly binding to free thiol-groups. The unique occurrence of disulphide-stabilized structures in eutherian spermatozoa may serve to protect the spermatozoon from structural degradation by its own proteolytic activity during the relatively slow passage through the eutherian egg investments.     

SEDIMENTARY STRUCTURES IN CAMBRIAN LIMESTONES STUDIED BY RADIOGRAPHY

The paper deals with radiographic studies of Middle Cambrian 'fragment limestone', and Upper Cambrian anthraconite concretions from Bornholm (Denmark). A very simple method provides good insight into the sedimentary structures of the rocks and hence a good foundation for interpretation of the lithogenesis.