Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.

Abstract: Daylength (photoperiod) influences the rate of reproductive development in the juveniles of some photoperiodic species. Recent studies show that daylength during the prenatal period is perceived by the fetus and that this perception can profoundly influence postnatal reproductive and somatic development. Using the photoperiodic Djungarian hamster, we assessed the role of the maternal pineal gland and its hormone, melatonin, in this prenatal perception of daylength. Maternal pinealectomy eliminated the influence of prenatal photoperiod on testicular and body weights of male pups, suggesting that a product from the maternal pineal gland communicates daylength to the fetus. Infusion of the pineal hormone melatonin into pinealectomized dams for various durations during gestation mimicked the effect of varying the prenatal photoperiod on both testicular and body weights. These results indicate that pineal melatonin is involved in this novel form of communication from mother to fetus.
Animal

Abstract: Endometriosis was induced surgically by implanting pieces of endometrium in the uterine mesenteries of 50 rats. Their fertility was then assessed after various treatments. Ten rats with endometriosis were treated with microsurgical excision of implants, 10 with high-frequency diathermy, 10 with danazol, and 10 with intraperitoneal indomethacin. Ten more rats had implants that were left untreated. The results were compared with those of ten rats that had sham surgery with implantation of fat in the uterine mesenteries. Reproductive performance was better in control animals with sham surgery than in animals with endometrial implants. Maximum restoration of fertility was achieved with indomethacin. Microsurgery and danazol therapy both were effective in preventing residual endometriosis, but the animals tended to be less fertile after treatment. Adhesions were most pronounced after diathermy and least pronounced after microsurgery or indomethacin therapy. In rats treated with indomethacin, persistent endometriotic cysts were invariably smaller near the site of intraperitoneal injection: this suggests a local antiprostaglandin effect.
Animal

Abstract: Inflammatory bowel diseases (IBD) has been characterized as having an autoimmune background. We studied the presence of immune interferon in the sera of a small number of patients with IBD. Antiviral activity was detectable in the sera of our patients with well-controlled IBD but it was mainly weak-positive (50% inhibition of virus CPE in a dilution of 1:10 per 0.2 ml of serum). The antiviral activity varied according to the sensitivity of the cell line used. The human amnion cells Wish (81%) and the human embryonic Intestine-407 (73%) were more sensitive.
Colitis, Ulcerative