Decidual Transformation Research Articles

Endometrial stromal cell decidualization inhibits human chorionic gonadotrophin and human placental lactogen secretion by co-cultured trophoblasts.

We have developed an in-vitro co-culture system to examine the interaction between purified first trimester cytotrophoblasts and purified non-pregnant human endometrial stromal cells (ESC). ESC decidualization is an important step in endometrial maturation and may modulate embryo implantation. In order to investigate the effects of ESC decidualization on trophoblast function, we examined human chorionic gonadotrophin (HCG), human placental lactogen (HPL), progesterone and estrogen secretion by trophoblasts co-cultured in contact with ESC, either with or without decidualization induced by progesterone. Decidualized ESC inhibited basal HCG and HPL secretion for 3 days during the culture for HCG, and for 5 days during the culture for HPL (P < 0.01 and P < 0.03 respectively). After 5 days of co-culture, decidual transformation of ESC as indicated by prolactin production occurred in the control cultures due to progesterone and oestradiol secretion by the co-cultured trophoblasts, but no significant differences in HCG or HPL secretion were observed between the two groups. Although the type of trophoblast used in the present study is far from implantation, our results clearly demonstrated that HCG and HPL secretion by trophoblasts was inhibited by the presence of co-cultured decidualized ESC, and suggested that ESC decidualization may regulate trophoblast function at the human fetal-maternal interface.

Uterine estradiol and progesterone receptor concentration in relation to circulating hormone levels and histoarchitecture during high endometrial sensitivity and induced decidualization in guinea pigs

Alterations in nuclear and cytosolic estradiol (ER) and progesterone (PR) receptor concentration in the antimesometrial (AM) and mesometrial (M) segments of the uterus in relation to circulating hormone levels, histology and surface topography during the period of high endometrial sensitivity and development of trauma-induced decidualization in cyclic guinea pigs were investigated. The period of high endometrial sensitivity (i.e. day 5 of the estrous cycle) was characterized by elevated plasma estradiol and progesterone and their receptors in the nuclear and cytosolic fractions of the uterus. There was, however, no difference in the concentration of these receptors or the surface ultrastructure in the AM and M segments. Unilateral traumatization by scissor cut along the AM length of the uterus on day 5 of the estrous cycle induced decidual cell reaction resulting in a marked increase in weight of the decidualized (traumatized) uterine horn with advancing decidualization to reach maximum levels (926% of the contralateral nontraumatized uterine horn) 7 days after traumatization. This was associated with decidual transformation and a marked increase in nuclear and cytosolic ER and PR concentration in the AM segment of the traumatized uterine horn. An increase in receptor concentration in the M segment of the traumatized uterine horn or the AM segment of the nontraumatized uterine horn was transitory and of a low order. Receptor concentration in the M segment of the nontraumatized uterine horn remained low throughout days 8–12 of the cycle. Findings indicate a possible role of both estradiol and progesterone in induction of endometrial sensitivity and development and maintenance of decidua in the guinea pig.

Nonpituitary human prolactin gene transcription is independent of Pit-1 and differentially controlled in lymphocytes and in endometrial stroma.

Expression of the human PRL (hPRL) gene in extrapituitary sites such as the uterus (decidualized endometrial stroma and myometrium) and cells of the hematopoietic lineage is directed by an alternative promoter which is located approximately 6 kilobases (kb) upstream of the pituitary-specific start site. In order to delineate the tissue-specific mechanisms governing the control of nonpituitary PRL gene expression, we have cloned and sequenced 3 kb 5'-flanking DNA of the upstream decidual/lymphoid (dPRL) promoter. Based on sequence homology we identified two binding motifs for Pit-1 and seven half-sites for glucocorticoid receptor/progesterone receptor (PR) binding. We focused our studies on the role of Pit-1 and of PR as potential transcriptional regulators, since the POU domain protein Pit-1 is essential in the control of pituitary PRL expression, and progesterone induces decidual transformation of the endometrial stroma, a differentiation process during which the decidual PRL gene is activated. We demonstrate in a variety of cell types, including lymphocytes and endometrial stroma, that Pit-1 is not involved in the regulation of dPRL promoter/reporter gene constructs carrying 3 kb 5'-flanking DNA. Our experiments also show that activated PR does not confer direct transcriptional control on the dPRL promoter. When we compared the activity of the transfected dPRL promoter in PRL-secreting and nonsecreting lymphoid cells, we found that the 3 kb 5'-flanking region of the dPRL promoter did not contain elements restricting expression to only those lymphocytes that produce PRL but allowed expression of fusion reporter genes irrespective of the status of the endogenous PRL gene. This was in sharp contrast to endometrial cells where 3 kb 5'-flanking DNA conferred strong transcriptional activation on the dPRL promoter in decidualized endometrial stromal cells actively secreting PRL, but did not allow transcription in undifferentiated non-PRL-secreting endometrial stromal cells. Activation of the dPRL promoter construct in these undifferentiated cells could however be induced by the addition of cAMP, in the absence of progesterone, suggesting that a signal transduced through the cAMP signaling pathway is a primary inducer of decidual PRL gene expression.

Implantation and decidualization in rodents

This article reviews the main events of embryo-implantation and decidualization in rodents. In common laboratory rodents the embryo attaches to the uterine epithelial lining, usually on days 4 to 6 of pregnancy. A progressive degree of proximity between trophoblast and epithelium occurs until the epithelial cells undergo apoptosis and detach from the basement membrane. During the attachment stage, the spindle-shaped connective tissue cells that underlie the epithelium next to the embryos transform into polyhedral and closely packed decidual cells. Following the epithelial detachment and the breaching of the basement membrane the embryo is thus in direct contact with decidual cells. These cells accumulate organelles associated with synthesis of macro-molecules, intermediate filaments, and eventually lipid droplets and glycogen. Another remarkable feature of decidual cells is the establishment of gap and adherens intercellular junctions. Differentiation of fibroblasts into decidual cells advances antimesometrially and mesometrially, creating in the endometrium several regions of cells with different morphology. The whole phenomenon of decidualization which is normally triggered by the embryo can be artificially induced in pseudo-pregnant or hormonally-prepared animals with the use of diverse stimuli. The uterine epithelium is probably responsible for the transduction of the initial stimulus. Prostaglandins have been shown to be important in the induction of decidualization. More recently other substances such as leukotrienes, platelet-activating factor (PAF), and transforming growth factor (TGF) have been thought to play a role in induction. Much evidence points to prostaglandin production by the decidual cells. New proteins such as a luteotropic factor, desmin, and other molecules were shown to be produced after rat stromal cells undergo decidual transformation. The extracellular matrix of the mouse decidua contains very thick collagen fibrils. Mouse decidual cells are also very active in phagocytosing the thick fibrils, contributing to the remodeling and involution of the decidua that accompanies embryonic growth. Radioautographic data indicates that mouse decidual cells produce and secrete collagen and sulfated proteoglycans.

Steroid and peptide regulation of insulin-like growth factor-binding proteins secreted by human endometrial stromal cells is dependent on stromal differentiation.

Endometrial stromal cells undergo decidual transformation, in response to epidermal growth factor (EGF) and progesterone. Since insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) are believed to be involved in endometrial differentiation, and insulin regulates IGFBP production in a variety of cells, we have investigated the modulatory roles of EGF, progesterone, and insulin on IGFBP secretion by long term cultures of human endometrial stromal cells. Without insulin, the principal IGFBP secreted into conditioned medium, detected by Western ligand blotting, was a 28-kilodalton (kDa) IGFBP, identified by immunoprecipitation as IGFBP-1. This was observed only when the stromal cells were decidualized. With increasing insulin, IGFBP-1 decreased to undetectable levels. Concomitantly, IGFBP-2 increased, as did a 24-kDa IGFBP (believed to be IGFBP-4) and a 28-kDa IGFBP, shown to be a glycoprotein by endoglycosidase sensitivity (and believed to be glycosylated IGFBP-4). In the nondecidualized state, insulin increased the secretion of IGFBP-3, IGFBP-2, and the 24-kDa IGFBP, which were slightly inhibited by EGF and relatively unaffected by progesterone alone. In the absence of insulin, progesterone weakly stimulated IGFBP-1 secretion, which increased markedly when the cells were decidualized by combined treatment with EGF and progesterone. These data show that IGFBP-3, IGFBP-2, IGFBP-1, and presumably IGFBP-4 and its glycosylated form are differentially regulated by peptide and steroid hormones in endometrial stromal cells and that their regulation is a function of stromal differentiation.

Effect of RU 486 on the endometrial response to deciduogenic stimulus in ovariectomized rhesus monkeys treated with oestrogen and progesterone.

Using the artificial plaque--decidual cell model in rhesus monkeys, the potential role of progesterone in the process of of epithelial and stromal cell responses was investigated by time-adjusted application of an antiprogestin, RU 486. Epithelial plaque formation is an immediate response of the endometrium to either trauma or invading trophoblast cells. To study this process, RU 486 (2.5 mg/kg body weight) or vehicle (ethanol/saline, 7:3, v/v, i.m.) was administered to the first group of monkeys immediately following traumatization (days 16 and 17 of treatment cycle). Histometric analysis revealed that treatment with RU 486 led to significant inhibition (P less than 0.001) in the recruitment of epithelial cells into plaque acini and consequent reduction (P less than 0.001) in the spread of the plaque reaction compared with control monkeys. In the second group of monkeys, experimental treatment was delayed until plaque formation had occurred (days 21 and 22 of cycle). RU 486 induced increased degeneration (P less than 0.01) in plaque cells. Thus the transformation and the maintenance of the epithelial plaque response appears to be progesterone-dependent. Glandular epithelium showed only marginal changes (P less than 0.05) in maximum cell height, amount of pseudostratification and secretory activity of glands as a consequence of RU 486 treatment; however, the antiprogestin induced a higher incidence of glandular apoptosis (P less than 0.01 for both groups). It has been suggested that the higher degree of apoptosis in the glandular epithelium could be a consequence of the progesterone receptor blocking action of RU 486. No distinctive change in endothelial cell ultrastructure was evident following RU 486 treatment; however, venular diameter was significantly increased (P less than 0.01, group I; P less than 0.001, group II) along with an apparent reduction in the extent of oedema. There was increased extravasation (P less than 0.01) and leukocytic infiltration (P less than 0.001, group I; P less than 0.05, group II) following RU 486 treatment. RU 486 induced vascular responses and increased diapedesis could presumably have resulted from its progesterone blocking action in vascular cells. RU 486 accelerated the incidence (P less than 0.01) of stromal decidualization (group I), as well as quantitatively accentuating (P less than 0.001) the decidual cell reaction (group II). It is possible that RU 486 may inhibit specific functions of decidual cells, despite morphologically consistent decidual transformation.

Peritoneale Deziduose: Ursache für einen mechanischen Ileus in der Schwangerschaft

Decidual transformation of the peritoneum is a frequent occurrence during pregnancy. Incidence and pathogenesis are vague. Complications like bleeding, suspicion of cancer and adhesions are rare. We present a case of mechanical ileus, followed by acute prerenal failure of the kidney caused by decidual transformation of the peritoneum.

Decidual Transformation of Human Extrauterine Mesenchymal Cells Is Associated with the Appearance of Insulin-Like Growth Factor-Binding Protein-1

Human extrauterine decidual cells were studied for the presence of insulin-like growth factor-binding protein-1 (IGFBP-1) by using an avidin-biotin complex immunoperoxidase method with a purified monoclonal antibody 6303 against IGFBP-1. It is well established that human decidua expresses mRNA for IGFBP-1 and synthesizes and secretes this protein. We now describe, for the first time, that cells morphologically similar to uterine decidual cells found beneath the peritoneal mesothelium in inguinal hernia and in the cervical mucosa during normal pregnancy and in the mesenchymal tissue of the Fallopian tubes and ovaries at term react with the monoclonal antibody for IGFBP-1 equally to endometrial decidual cells. These results imply that the extrauterine mesenchymal cells, which have undergone decidual transformation, are not only morphologically but also functionally, similar to their counterparts in the uterus. Secondly, the data suggest that IGFBP-1 expression is associated with a special type(s) of cells and a certain stage of differentiation rather than special organs in the body.

Local Regulation within the Female Reproductive System and upon Embryonic Implantation: Identification of Cells Expressing Proenkephalin A

The detection of proenkephalin A (PEA) mRNA and encoded peptides in various regions of the female reproductive system raised the possibility that opioid peptides might act as local regulators within this system. Assignment of a specific role for locally synthesized enkephalins has been hampered, however, by the unknown identity of the cells that produce PEA. Using in situ hybridization analysis we have now identified the cell types that express PEA mRNA in the reproductive system of female mice. In the ovary, PEA mRNA was localized primarily in theca cells of preovulatory follicles, and to a lesser extent, in follicular granulosa cells. In the oviducts, where PEA mRNA is most abundant, expression was confined to the secretory and ciliated epithelium of the mucosa. In the uterus, the site of PEA mRNA expression was the deep glandular layer of the endometrium. When pregnancy ensues, and upon decidual transformation, PEA expression by the same uterine cells was dramatically elevated. Elevated levels of PEA mRNA were detected predominantly in the vicinity of the implantation site, suggesting that signaling by the implanted embryo play a role in stimulating PEA expression. Based on these results, possible physiological roles for PEA-encoded peptides as autocrine/paracrine regulators within the female reproductive system are suggested.

Endometrial response to deciduogenic stimulus in ovariectomized rhesus monkeys treated with oestrogen and progesterone: an ultrastructural study

The present work continues our aim of establishing an experimental model to study the decidual cell reaction to an artificial deciduogenic stimulus in the long-term ovariectomized rhesus monkey treated with oestrogen followed by progesterone. The fine structural details of decidual, granular and plaque cells, which constituted the endometrial cellular response to the deciduogenic stimulation in the present study, revealed striking similarities with those reportedly present in an endometrial response to blastocyst implantation in the rhesus monkey. Plaque epithelia showed a significant degree of hypertrophy, hyperplasia and differentiation followed by a steady degeneration by day 32 (equivalent to day 16 after trauma) of treatment. The plaque cells were shown to contain numerous regular-shaped mitochondria, polyribosomes and large amounts of rough endoplasmic reticulum (RER) in their cytoplasm and were characteristically arranged in clusters or acini formation surrounded by discrete basal laminae. As early as day 28 of treatment, the initiation of stromal decidual cell transformation was noted and, by day 48, a sizeable pool of decidual cells was found. The decidual cells had rounded nuclei and elaborate arrangements of interconnected cisternae of RER which were often moderately dilated and filled with amorphous, electron-dense material. Granular cells were characterized by eccentrically located nuclei and numerous membrane-bound, electron-dense granules in their cytoplasm and were found in increasing numbers in the stroma around decidual cells, blood vessels and glandular epithelia.(ABSTRACT TRUNCATED AT 250 WORDS)

Fibronectin and cell shape in vivo: studies on the endometrium during pregnancy.

The rat endometrium during pregnancy was used as a model system to study fibronectin in vivo. Fibronectin distribution on stromal fibroblasts, as determined by indirect immunofluorescence staining, was studied in relationship to cell shape during decidual transformation. Fibroblasts of the estrus endometrial stroma were elongated cells with a fibrillar pattern of fibronectin on their surfaces. During days 1-6 of pregnancy, as these elongated cells acquired a round morphology, fibronectin changed first to a patched distribution on the cells'a surfaces and then disappeared. The change in fibronectin was specific for the fibroblasts since over the same time period there was no decrease in fibronectin found associated with blood vessels or in the epithelial-stromal basement membrane. These results support the proposed relationship between cell surface fibronectin and cell shape that has been inferred from in vitro experiments. After implantation, fibronectin distribution was studied in relationship to the position of the conceptus. In the stroma proximal to the implanting conceptus, fibronectin was absent except around blood vessels, which may help explain how decidual tissue could act as a barrier to trophoblast invasion. Finally, fibronectin distribution was studied in the uterus after parturition. Debris in the uterine lumen was coated with fibronectin, which may be important in the rapid removal of this material by phagocytic cells. Also, fibronectin associated with the epithelial-stromal basement membrane was reorganized after reepithelialization had occurred.

Zytologische und kolposkopische Diagnose der dezidualen Ektopie der Zervix*

The cytological and colposcopic fundamentals for correct diagnosis have been compiled in this article on the basis of 86 cases with residual transformation of the cervix. Colposcopically, the decidual transformation of the portio was subdivided into 4 groups, and the colposcopic characteristics of ectopia decidualis were defined. For cytological clarification of decidual transformation of the cervix, two smears are required. The first, taken from the lateral vault of the vagina, enables an insight into the hormonal functioning of the vaginal mucosa. The second smear is prepared by scraping off the transformed tissue. The smear also contains cells from the lower stratum. These are the decidually transformed stroma cells. Evaluation of these preparations and final diagnosis should be effected by an experienced and skilled cytologist. Colposcopic-cytological examination can supply sufficient diagnostic material to eliminate the need for biopsy for the purpose of histological examination. This has been tested in 21 cases of decidual ectopy.

In vitro decidualization of rat endometrial cells.

Rat endometrial cells were isolated from ovariectomized adults submitted to a progesterone-estradiol sequence proper to sensitize the uterus to respond to a deciduogenic stimulus, and then cultured in vitro in the presence of progesterone. They grew rapidly and became morphologically similar to the decidual cells occurring in vivo with regard to the binucleation and the accumulation of characteristic filamentous material in the cytoplasm. The life-span of the decidualized cells in vitro was comparable to the duration of the deciduoma in vivo. The progesterone treatment of the rat was found to be a prerequisite for such development and transformation of endometrial cells in vitro, since control experiments performed with nonhormonally injected castrated animals gave only isolated islets of epithelial cells and scattered fibroblast-like cells in culture, whereas the decidual transformation was still observed, although with some delay, with cells from progesterone (but not estradiol)-treated spayed rats. Such an in vitro system may provide a new opportunity to study the mechanism of decidualization and of its hormonal control.

Histology Of The Baboon Endometrium During The Menstrual Cycle And Pregnancy

The histologic characteristics of baboon endometrium during the menstrual cycle and pregnancy were studied and compared with those of human endometrium. Eight phases of endometrial change during the menstrual cycle are described. The samples were dated on the basis of sex skin changes. The basic histology of the baboon endometrium is similar to that of human endometrium, but some differences were observed. The growth of baboon endometrium is more sluggish, secretion is less intense, and many of the changes, especially in the stroma, are localized, less diffuse than they are in human endometrium. During pregnancy, decidual transformation in the baboon is much less intense than that in the human. No differences were observed between endometrium in association with preimplantation embryos and that from nonpregnant animals at comparable times following ovulation.

Contraception by intrauterine release of progesterone—Effects on endometrial trace elements, enzymes and steroids

Endometrial biopsies were obtained in the proliferative phase (days 10–12) and in the secretory phase (days 20–23) in two consecutive cycles before insertion and after 2 and 6 months use of the ALZA-T device, which releases 65 μg progesterone/24 h and a Placebo-T of exactly the same shape and size and manufactured by the same material. Twenty-five women were studied with the ALZA-T and 20 women with the Placebo-T.The endometrial concentrations of copper, zinc and manganese were determined as well as the endometrial protein concentration and the activity of alkaline and acid phosphatase, betaglucuronidase and total lactic dehydrogenase. The endometrial concentration of progesterone and estradiol were determined using a radioimmunoassay. The insertion of the progesterone releasing device induced major changes in the morphological picture of the endometrium with a decidual transformation and atrophy of the glands. The zinc concentration of the secretory endometrium was decreased while the manganese concentration was increased, thus abolishing the physiological difference between the phases. Both the ALZA-T and the Placebo-T increased the endometrial protein concentration. There was a significant decrease in alkaline phosphatase and betaglucuronidase activity while the acid phosphatase increased and the total lactic dehydrogenase showed a biphasic variation with an increase in the proliferative and a decrease in the secretory phase. No effect on endometrial enzymes was induced by the Placebo-T.Finally, the presence of the ALZA-T in utero increased endometrial progesterone levels and decreased estradiol levels without any concomitant change in the circulating levels of the same steroids.

Ultrastructural features of blastocyst attachment and trophoblastic invasion in the rat.

Summary. Morphological features of the interaction between the implanting blastocyst and the uterine endometrium were studied by electron microscopy, using material fixed in situ. The observations extended from the pre-attachment stage to the completion of trophoblastic erosion of the uterine epithelium and early decidual transformation of the stromal cells. After shedding of the zona pellucida, the blastocyst establishes contact with the tips of microvilli and with bleb-like cytoplasmic protrusions of the epithelial cells. Attachment occurred during the afternoon of the 5th day post coitum (p.c.). Patches of`bristle-coated' membrane appeared on the trophoblast membrane at that time. A lattice-like substructure was discernible in the cytoplasmic plaques, which are abundant in the early blastocyst. Sperm-tail inclusions were observed in both trophoblast and inner cell mass as late as Day 5 p.c. By the 6th day p.c., the epithelial microvilli were usually lost and the trophoblast membrane interlocked with that of the epithelial cells, with frequent formation of tight junctions. Leucocytes were occasionally seen in the epithelial layer at the attachment site. Unusually electron-dense cells were often found wedged between the trophoblast and epithelial cells; their possible relation to Wilson bodies is discussed. The earliest morphological response of the stromal cells to blastocyst attachment was the appearance of changes in nuclear shape, chromatin distribution and nucleolar structure in the subepithelial layer. The deeper subepithelial stroma became oedematous, and diapedesis, erythro-phagocytosis and later the formation of sinusoids could be observed. During Day 7 p.c., the basement membrane generally disappeared and the trophoblast cells were then in close contact with stromal cells : the distance between the two unit membranes was in the range 100 to 200 Å. A `periplacental fibrinoid barrier' could not be recognized at this stage, but the existence, or later development, of such an immunological barrier could not be excluded. Stromal cells undergoing decidual transformation showed an abundance of membrane-bound ribosomes and a striking accumulation of fibrils, 80 to 90 Å in diameter, displacing the cytoplasmic organelles. The development of Reichert's membrane was traced from its first appearance as an amorphous deposit along the inner wall of the trophoblast on Day 6 p.c., to the formation of a stratified, membranous structure on the 8th day.

The role of uterine inflammation in the inhibition of decidualization by intraluminal antihistamines.

It is well known that the decidual transformation of the rat uterus can be inhibited by the intraluminal administration of antihistaminic drugs. Recent studies on intrauterine foreign bodies in rats have indicated that a uterine inflammatory reaction can also inhibit decidualization. It was therefore of interest to determine whether uterine inflammation might result from the intraluminal administration of antibistaminic drugs in doses sufficient to inhibit decidualization. Four antihistaminic drugs were used. Each was administered at a dose of 1.0 mg per horn to the lumen of one uterine horn in six rats on Day 2 of pregnancy. In all animals this treatment resulted in an inflammatory reaction in the endometrium on Day 5 of pregnancy. In addition, 1.0 mg of Dibenamine was administered to the lumen of one uterine horn in six rats and inflammation was again noted in each case. Dibenamine at 1.0 mg per horn completely prevented decidualization in one horn in five rats, and at 0.5 mg per horn resulted in an average inhibition of 79% in one horn in six rats. Dibenamine is an adrenergic blocking agent with very little antihistaminic activity, and it would not be expected to inhibit decidualization in this dose range if only antihistaminic activity were involved. These observations suggest that the inhibition of decidualization produced by intraluminal antihistamines is due to uterine inflammation, rather than to the antihistaminic activity. This interpretation conflicts with the proposal that histamine may be the physiological inducer of the decidual reaction.

On the indcidence of spontaneous decidualization in the rat.

Recently, in a brief communication, Coppola, Ball & Brown (1966) reported an incidence of 17% spontaneous deciduomata in pseudopregnant rats. One to three discrete zones of decidualization per uterus were observed. One of us, (M.C.S.), who has been concerned with the problem of decidualization for many years, has never observed as high an incidence of spontaneous decidualization. Because of the importance of the decidual response and decidual induction as a model system in the study of nidation (Shelesnyak, 1957) and of mammalian tissue growth and differentiation (Shelesnyak, 1962), it is essential to have a reliable index of the efficiency, or lack thereof, in induction of the decidual response under experimental conditions. Any degree of spontaneous decidualization would decrease the reliability of the experimental system by making unreliable such usual criteria as the weight of the uterus and/or the proportion of the uterus undergoing the decidual transformation. The reported high incidence of spontaneous decidualization in pseudopregnant rats therefore warranted re-investigation of the incidence in our own colony. The rats of the Biodynamics colony, originally of Wistar stock, have been colony-bred for the past 15 years. They were maintained in air-conditioned quarters under a natural light-cycle, or, during the last 3 years, under a timed cycle of 14 hr of artificial light and 10 hr of darkness. Purina Laboratory Chow and tap water were freely available. Pseudopregnancy was induced by electrical stimulation of the cervix uteri on the days ofpro-oestrus and oestrus (Shelesnyak, 1931), or by mating with vasectomized male rats. Routine daily vaginal smearing was performed, the first day of the leucocytic vaginal smear being designated as Day L1. Rats were examined for decidual reactions by autopsy or by laparotomy on Day L8. In our experience, this would be the time of maximal decidual development (Lobel, Tic & Shelesnyak, 1965). The data, assembled in Table 1, were collected over the past 8 years from groups of animals used as untreated controls in various experiments as well as from animals observed specifically for occurrence of spontaneous decidual reactions. Of 280 female rats examined, 5% showed apparently spontaneous decidual reactions. In only one rat did response occur in each uterine horn

Decidual transformation of the cervical stroma simulating reticulum cell sarcoma

Two patients are presented who developed polypoid lesions of the cervix during pregnancy, which were initially diagnosed as primary reticulum cell sarcoma. The subsequent clinical course of each patient and a review of the microscopic sections of each lesion suggest that the changes represented an atypical decidual transformation rather than a sarcoma. Characteristics which might aid in differentiating this bizarre but benign lesion from a sarcoma have been presented. The importance of considering the possibility of this innocuous phenomenon in the differential diagnosis when cervical neoplasms are found during pregnancy has been emphasized.

The Arias-Stella phenomenon in the diagnosis of ectopic pregnancy

1.1. Among 124 endometria obtained preoperatively in cases of tubal pregnancy, decidual transformation of the endometrium was found in 55 cases (44.3 per cent). Endometrium without decidual transformation was found in 69 cases (55.7 per cent). In 29 of the 69 cases, i.e., in 42.0 per cent, the diagnosis of pregnancy was established by the histological finding of a positive Arias-Stella reaction.2.2. Out of a total of 88 endometrial analyses (19 with and 69 without decidual reaction), a positive Arias-Stella reaction was found in 42 cases (47.7 per cent), and an uncertain Arias-Stella reaction in 14 cases (15.9 per cent).3.3. The use of the Arias-Stella reaction for histological diagnosis of pregnancy increased the percentage of correctly diagnosed cases in this series from 44.3 to 67.7 per cent. Although this reaction does not represent a specific histological test for ectopic pregnancy it can be of practical value for early diagnosis of ectopic pregnancy as well as for differential diagnosis in cases of metrorrhagia.4.4. In the histogenesis of the Arias-Stella reaction, inflammatory changes are of no significance. Explanations of the etiology of the phenomenon by Arias-Stella and others are discussed.