Basal Endometrium Research Articles

Fine Structural Effects of Intrauterine Contraceptives on the Human Endometrium

Of 198 endometrial biopsies performed on 82 women with Lippes loops in situ for 6 weeks to 40 months 124 were proliferative and 74 were secretory. Samples were obtained from immediately beneath the device between the loops and from areas remote from the device. Specimens of basal endometrium lower segment or endocervix were excluded. Control tissue was obtained before insertion of the device. Slides were prepared for electron microscopy. No consistent generalized pathologic change was observed in either proliferative or secretory endometria. The stroma immediately beneath the loop appeared compressed and fibrotic throughout the cycle. Proliferative epithelium maintained the normal pattern of juxtaposed light and dark (electron-dense) cells mitotic activity and distribution of microvilli and cilia. No progression of epithelial ultrastructural differences occurrred after their first appearance in the second month after IUD insertion. Precocious changes in epithelial ultrastructure included 1) the appearance of a nucleolar channel system normally considered indicative of ovulation or exogenously administered hormones in 15-29% of endometria judged to be preovulatory; 2) numerous large mitochondria usually associated with the postovulatory phase in the late-proliferative endometrium and occasionally as early as in the midproliferative; and 3) the development of confluent fields of glycogen at the end of the proliferative phase a few days earlier than in controls. The premenstrual endometrium resembled the contrl of this stage; scarcity of microvilli and other characteristic ultrastructural traits of regression were noted. Ultrastructural changes in the proliferative stroma were observed first about 1 day preovulatory when the cytoplasm appeared better differentiated than in the controls. The stromal cells were highly differentiated at the end of the first postovulatory week; the cytoplasmic complexity at Days 19 or 20 often resembled that of Day 25 controls. Premature and asynchronous development of the endometrium may affect the correlation with ovular development which is a prerequisite for normal implantation. Since the IUD creates an unfavorable environment for blastocystic attachment but does not dislodge the implanted ovum its action is considered contraceptive rather than abortifacient in the usual sense.

Progestation

ABSTRACT Autoradiographic, enzymic and histologic studies on uteri of pregnant rats were carried out to follow the endometrial modifications which take place during progestation (days L0 – L4) and culminate in the state of uterine receptivity essential for ovum-implantation. Pulse labelling with tritiated thymidine (radioactive DNA precursor) on L0, L1 and L2 revealed a sequence of cell renewal in luminal and glandular epithelium and endometrial stroma. On L3 and L4 stromal cells showed extensive incorporation of tritiated thymidine. This synthetic activity was associated with endometrial preparation for decidualization and was evoked at least in part, by the surge of oestrogen on L3. All layers of the uterine wall were heavily infiltrated on L0 and resembled the site of an acute inflammatory reaction. Subsequently, polymorphonuclear infiltration diminished and monocytic cells predominated. On L3 a spatial arrangement was observed: eosinophiles were concentrated in the basal endometrium and monocytic cells in the subepithelial stroma. A comparison was made between such a shift in migratory cells in the uterus and similar phenomena which occur in inflammatory and immune reactions. Activities of acid and alkaline phosphatases, of ATP-ase and succinic dehydrogenase were low on L0 and L1 during the periods of infiltration, degeneration and regeneration of luminal and glandular epithelium. Enzymic activities increased on the following days, (L3 and L4). Vascular dilation and engorgement and endometrial oedema were observed near the blastocysts on L4. Most blastocysts incorporated tritiated thymidine after 14.00 h on L4, but some showed uptake before loss of the zona which occurs usually between 14.00 and 16.00 h; therefore, it was assumed that the permeability of the zona increases prior to being shed. Activities of succinic dehydrogenase and acid and alkaline phosphatases were demonstrable in blastocysts on L4 while they were still »free« in the uterine lumen.

The effect of relaxin on the endometrium of monkeys histological and histochemical studies

AbstractCastrated or juvenile monkeys were given estrogen, progesterone and relaxin in various doses and combinations. Relaxin induced: (1) a dilatation of the superficial endometrial blood vessels and proliferation of their endothelial cells; this effect may be regarded as due to relaxin alone; (2) an intensified differentiation of the endometrial stroma cells into predecidual cells and granulocytes, dependent on estrogen priming and the simultaneous injection of progesterone; (3) a periarteriolar mantle‐like accumulation of granulocytes in the basal endometrium dependent on the above pretreatment; (4) a degranulation of the granulocytes and hypersegmentation of their nuclei following prolonged administration of relaxin with estrogen and progesterone. Morphologically and histochemically the granulocytes of the monkey are almost identical with those of the human uterus and with the granular cells in the decidua and mesometrial gland of the pregnant rat. Immunohistologically relaxin has been demonstrated in the granulocytes of man and rat. The changes in the arterioles brought about by exogenous relaxin occur under physiological conditions only with the increased formation of endogenous relaxin during early pregnancy. They have been described in the immediate vicinity of ovum implantation in man, monkey, and rat. Their function possibly lies in the preparation of blood spaces for nutrition of the young embryo.

Studies on the mechanism of nidation. XVII. Histochemical analysis of decidualization in the rat. 3. Formation of deciduomata.

ABSTRACT Histochemical observations were made on the activities of adenosinetriphosphatase, alkaline and acid phosphatase, and on RNA, glycogen and lipids as well as connective tissue elements in uteri of pseudopregnant rats during the period of formation of deciduomata, i. e. between 36 to 96 hours after the administration of the inducing stimulus. Enzymic activity accompanied the formation of deciduomata, stopped at the limits of the decidual cell reaction and did not involve the rest of the endometrium. A distinct line of demarcation between the two tissues (deciduoma and basal endometrium) was demonstrated both histologically and histochemically. This demarcation is independent of the manner of stimulation or the extent of the decidual cell reaction.

Alkaline and Acid Phosphatase Activity in the Endometrium and Ovary of Swine

The levels of activity and the distribution of alkaline and acid phosphatase in the ovary and endometrium of gilts slaughtered at various stages of the estrous cycle and early pregnancy were determined by biochemical and histochemical methods. Alkaline phosphatase activity in the endometrium varied markedly, ranging from an average of 9.30 units 3 days after breeding to 0.46 units 25 days after breeding. Differences between periods were highly significant. Changes in the distribution of the enzyme were also observed. At 3 days after breeding alkaline phosphatase was concentrated in the surface and upper glandular epithelium. By 25 days after breeding the enzyme was largely confined to the glandular epithelium. Acid phosphatase activity in the endometrium increased from an average of 1.03 units during estrus to 5.71 units 25 days after breeding. Differences between periods were highly significant. The enzyme was confined to epithelial cells and was most prominent in the basal endometrium. In the ovary alkaline phosphatase was found in the theca interna at all periods studied. The granulosa cells did not show activity. Activity was generally low in the corpus luteum, but increased from estrus to 25 days after breeding. Acid phosphatase activity was low in all parts of the ovary and did not appear to fluctuate with stage of cycle or pregnancy.