Silexan does not cause withdrawal symptoms even when abruptly discontinued.

OBJECTIVE: Subsequent to a randomised, double-blind, double dummy clinical trial assessing the efficacy of silexan compared to placebo and paroxetine in patients suffering from generalised anxiety disorder (GAD), a 1week follow-up phase was added in order to assess possible withdrawal symptoms of silexan after abrupt discontinuation. METHODS: Participants received silexan 80 mg/d, silexan 160 mg/d, paroxetine 20 mg/d, or placebo at a ratio of 1:1:1:1. Study medication was discontinued after the 10 week active treatment phase of the original trial. Whereas paroxetine was tapered as indicated, silexan administration was discontinued abruptly. Assessment of possible withdrawal effects was done using the Physician Withdrawal Checklist questionnaire (PWC-20). RESULTS: During the 1 week down-titration phase, mean total PWC-20 scores had reduced by 0.19 in placebo, 0.23 in silexan 80, 0.65 in silexan 160, and 0.51 in paroxetine. The median change in all four groups was 0.00. In none of the treatment groups withdrawal effects occurred after discontinuation. CONCLUSIONS: Values assessed for the silexan groups indicate the absence of a dependency potential of this preparation.

A multi-center, double-blind, randomised study of the Lavender oil preparation Silexan in comparison to Lorazepam for generalized anxiety disorder.

Generalized and persistent anxiety, accompanied by nervousness and other symptoms (Generalised Anxiety Disorder, GAD) is frequent in the general population and leads to benzodiazepine usage. Unfortunately, these substances induce sedation and have a high potential for drug abuse, and there is thus a need for alternatives. As the anxiolytic properties of lavender have already been demonstrated in pharmacological studies and small-scale clinical trials, it was postulated that lavender has a positive effect in GAD. A controlled clinical study was then performed to evaluate the efficacy of silexan, a new oral lavender oil capsule preparation, versus a benzodiazepine. In this study, the efficacy of a 6-week-intake of silexan compared to lorazepam was investigated in adults with GAD. The primary target variable was the change in the Hamilton Anxiety Rating Scale (HAM-A-total score) as an objective measurement of the severity of anxiety between baseline and week 6. The results suggest that silexan effectively ameliorates generalized anxiety comparable to a common benzodiazepine (lorazepam). The mean of the HAM-A-total score decreased clearly and to a similar extent in both groups (by 11.3+/-6.7 points (45%) in the silexan group and by 11.6+/-6.6 points (46%) in the lorazepam group, from 25+/-4 points at baseline in both groups). During the active treatment period, the two HAM-A subscores "somatic anxiety" (HAM-A subscore I) and "psychic anxiety" (HAM-A subscore II) also decreased clearly and to a similar extent in both groups. The changes in other subscores measured during the study, such as the SAS (Self-rating Anxiety Scale), PSWQ-PW (Penn State Worry Questionnaire), SF 36 Health survey Questionnaire and Clinical Global Impressions of severity of disorder (CGI item 1, CGI item 2, CGI item 3), and the results of the sleep diary demonstrated comparable positive effects of the two compounds. In conclusion, our results demonstrate that silexan is as effective as lorazepam in adults with GAD. The safety of silexan was also demonstrated. Since lavender oil showed no sedative effects in our study and has no potential for drug abuse, silexan appears to be an effective and well tolerated alternative to benzodiazepines for amelioration of generalised anxiety.

Long-term efficacy and safety of a combination of sabal and urtica extract for lower urinary tract symptoms--a placebo-controlled, double-blind, multicenter trial.

The efficacy and tolerability of a fixed combination of 160 mg sabal fruit extract WS 1473 and 120 mg urtica root extract WS 1031 per capsule (PRO 160/120) was investigated in elderly, male patients suffering from lower urinary tract symptoms (LUTS) caused by benign prostatic hyperplasia in a prospective multicenter trial. A total of 257 patients (129 and 128, respectively) were randomized to treatment with PRO 160/120 or placebo (127 and 126 were evaluable for efficacy). Following a single-blind placebo run-in phase of 2 weeks, the patients received 2 x 1 capsule/day of the study medication under double-blind conditions over a period of 24 weeks. Double-blind treatment was followed by an open control period of 24 weeks during which all patients were administered PRO 160/120. Outcome measures for treatment efficacy included the assessment of the patients' LUTS by means of the I-PSS self-rating questionnaire and a quality of life index as well as uroflow and sonographic parameters. Using the International Prostate Symptom Score (I-PSS), patients treated with PRO 160/120 exhibited a substantially higher total score reduction after 24 weeks of double-blind treatment than patients of the placebo group (6 points vs 4 points; P=0.003, one tailed) with a tendency in the same direction after 16 weeks. This applied to obstructive as well as to irritative symptoms, and to patients with moderate or severe symptoms at baseline. Patients randomized to placebo showed a marked improvement in LUTS (as measured by the I-PSS) after being switched to PRO 160/120 during the control period (P=0.01, one tailed, in comparison to those who had been treated with PRO 160/120 in the double-blind phase). The tolerability of PRO 160/120 was comparable to the placebo. In conclusion, PRO 160/120 was clearly superior to the placebo for the amelioration of LUTS as measured by the I-PSS. PRO 160/120 is advantageous in obstructive and irritative urinary symptoms and in patients with moderate and severe symptoms. The tolerability of the herbal extract was excellent.

Efficacy, safety, and acceptance of beclomethasone dipropionate administered via a new dry powder Inhaler or a standard CFC metered-dose inhaler in asthma patients.

BACKGROUND/OBJECTIVES: The mechanical aerosol generator, MAGhaler, is a new chlorofluorocarbon-free inhalation device. The objective of this trial was to show equivalent efficacy and safety of beclomethasone dipropionate (BDP) delivered via the MAGhaler and the metered-dose inhaler (MDI) in patients with mild to moderate bronchial asthma. Moreover, user-friendliness and acceptance of the two devices were compared. METHODS: This was a double-blind, reference-controlled, 12-week trial in 171 patients with asthma receiving BDP (1,000 microg/day) delivered via either the MAGhaler or the conventional MDI. Respiratory function parameters, clinical symptoms, concomitant intake of salbutamol or fenoterol, adverse events (AEs), laboratory values, and concomitant medications and diseases were recorded. The primary efficacy parameter was mean forced expiratory volume in 1 s (FEV1), measured after 4, 8, and 12 weeks of therapy. RESULTS: The equivalence of the two devices was confirmed (p = 0.003) on the basis of the ratios of the mean FEV1 in weeks 4 to 12. Mean (+/- SD) FEV1 (MAGhaler was 2.24 +/- 0.60 l (baseline), 2.61 +/- 0.90 litres (week 4), and 2.62 +/- 0.87 litres (weeks 4-12). Mean FEV1 (MDI) was 2.28 +/- 0.59 litres (baseline), 2.53 +/- 0.82 litres (week 4), and 2.56 +/- 0.77 litres (weeks 4-12). In total, 33 AEs occurred in 26 (30.2%) patients (MAGhaler) and 51 AEs in 36 (42.4%) patients (MDI). Most of the AEs were of mild or moderate intensity. The relationship to treatment could not be excluded for 11 AEs in 11 patients (MAGhaler) and 23 AEs in 18 patients (MDI). Three serious AEs, all unrelated to treatment, occurred in 3 patients (MAGhaler: 2, MDI: 1). There were no clinically relevant changes in other safety parameters. Most patients either preferred the MAGhaler or rated the two devices as equally acceptable. CONCLUSION: The new MAGhaler was equivalent to the standard MDI in terms of the safety and efficacy of BDP. The improved user-friendliness and acceptance of the MAGhaler over the conventional MDI represent an important advance in the clinical management of bronchial asthma.

Simultaneous exocrine and endocrine secretion: trophoblast and glands of the endometrial cups.

Invasion of trophoblast cells of the chorionic girdle into the endometrium and their subsequent dependence as endometrial cup cells on the maternal vascular system are unique features of equine gestation. This study of exocrine secretion by the endometrial glands and endocrine secretion by the cup cells was initiated to examine the relationships between and the effects of two disparate epithelial cell types sharing the endometrium. Endometrial cups were examined from day 36 to day 83 of gestation by light and electron microscopy, and immunohistochemical and lectin analysis. As the cup cells invade the endometrium they migrate along the basal lamina of glands, thus preserving the integrity of the glands. The hypertrophied cup cells develop an extensive network of cytokeratin-positive filaments and large Golgi zones that stain positively with antibodies to equine chorionic gonadotrophin and with the lectins SBA (agglutinin from Glycine max) and WGA (agglutinin from Triticum vulgaris). The endometrial glands within and immediately adjacent to the cup undergo substantial hypertrophy. The gland cells within the cup stain with alcian blue and with some lectins (agglutinins from Dolichos biflorus and lectin SBA), whereas gland cells in unmodified endometrium away from the cup stain positively with antibodies to transforming growth factor a, but only poorly with SBA. Secretory material in gland luminae in the cup stain heterogeneously with alcian blue, periodic acid Schiff and lectins. Later in gestation, glands within the cup become progressively disorganized, with some glands rupturing and releasing their contents into the stroma of the cup. Areas of lipid accumulation and apparent degeneration of cup cells were observed in the cups on day 83 of gestation only. In conclusion, it appears that cup cells substantially modify the integrity and secretion of adjacent endometrial glands, and that progressive disruption of gland integrity and isolation of endometrial vessels by extracellular matrix precedes deterioration of the cup cells. Necrosis and disintegration resulting from these factors appear more likely to limit cup lifespan than to cause programmed cell death of individual cup cells.

Preference of invasive cytotrophoblast for maternal vessels in early implantation in the macaque.

The interaction of cytotrophoblast with maternal endometrium, especially endometrial blood vessels, was examined in macaque gestational stages between 2 and 8 days after the onset of implantation. Serial sectioning of these early implantation sites allowed immunostaining of consecutive sections with a number of different antibodies, facilitating cell identification. In the earliest implantation site, immunostaining showed that antibody to cytokeratin stained cytotrophoblast, syncytial trophoblast, epithelial plaque and endometrial gland cells. However, only those cytotrophoblast cells near the maternal-fetal border and within vessels showed surface staining for neural cell adhesion molecules and only syncytial trophoblast showed SP1 reactivity. Even at this early stage cytotrophoblast filled the lumen of superficial arterioles, whereas dilated venules contained only a few cytotrophoblast cells. In later stages endovascular cytotrophoblast not only plugged many spiral arterioles but also migrated into the walls of these arterioles, and progressed into deeper coils. Displacement of endothelial cells and disruption of vessel walls were illustrated with antibody to factor VIII, TGF alpha, and desmin. Clusters of cytotrophoblast cells at the fetal-maternal interface tended to bypass clusters of epithelial plaque cells and larger clusters of maternal fibroblasts, but readily entered all vascular spaces. Consequently the vascular system constituted a major pathway of invasion, although the arterioles were the only component substantially invaded beyond the trophoblastic-shell/endometrial border.

Ultrastructural localization of pregnancy-specific beta 1-glycoprotein (SP1) and cathepsin B in villi of early placenta of the macaque.

Pregnancy-specific beta 1-glycoprotein (SP1) is found in maternal serum very early in gestation in both human and non-human primates. As judged by light microscopic immunocytochemistry, the major source of SP1 is the syncytial trophoblast, but little is known of the subcellular localization of SP1 indicative of the cellular pathway involved in secretion of the hormone. To study subcellular distribution of SP1, we used electron microscopic immunocytochemistry carried out on macaque placental villi from early (3-4 weeks) gestation. Both light and electron microscopic results confirmed localization confined to syncytial trophoblast in the villi. Within syncytial trophoblast labeling was predominantly over small granules in the apical cytoplasm. The Golgi complex also showed labeling, and light labeling was associated with the endoplasmic reticulum. For comparison, we also localized cathepsin B, a lysosomal protease. By way of contrast this enzyme was localized primarily in large cytoplasmic granules. The results are consistent with a secretory pathway including synthesis in the ER, processing by the Golgi complex, and exocytotic release into maternal blood in the intervillous space.

Differentiation of the inner cell mass of the baboon blastocyst.

During the blastocyst stage of development in the baboon, the inner cell mass changes from an irregular accumulation of cells within the cavity of the blastocyst to a disk at one side of the blastocyst and finally to a spherical mass of epiblast cells exhibiting a distinct polarity. The cells that will become the primitive endoderm are first seen as flattened but undifferentiated cells on the cavity side of the disk-shaped inner cell mass. After endoderm cells develop their typical cytological characteristics, they extend well beyond the inner cell mass to form parietal endoderm. A basal lamina develops associated with the epiblast cells and mural trophoblast, but not with either parietal or visceral endoderm. Cytological differentiation of inner cell mass cells includes increased numbers of polyribosomes and a change in mitochondria from long, convoluted structures to short, more typical shapes. Evidence that epiblast is polarized is seen by the late zonal blastocyst stage. Apical junctional complexes develop within the center of the epiblast. These junctions presage the development of the potential amniotic cavity. Large vacuoles containing cell debris, some of which contain nuclear fragments, are present at all stages. Extensive cell death occurs during growth of the blastocyst, but the pattern appears to be random and products of cell death are readily phagocytized by adjacent cells.

The morula-blastocyst transition in two Old World primates: the baboon and rhesus monkey.

Baboon and rhesus monkey embryos demonstrate compaction during the morula stage, although not all blastomeres participate simultaneously. During this process the outer adherent cells develop progressively more extensive apical junctional complexes. Several spaces appear between blastomeres before formation of a single cavity, and assortment of inner cell mass and trophoblast cells is less rapid and less precise in primates than in rodents. Nonhuman primates should prove appropriate for studies of individual aberrant blastomeres during blastocyst formation.

Differentiation of trophoblast of the baboon blastocyst.

The structure of trophoblast of the baboon blastocyst undergoes a number of maturational changes from the early blastocyst to the late blastocyst stage. The striking expansion of the blastocyst that occurs during the preimplantation period is accompanied by the development of an extensive endocytic apparatus. Cationized ferritin labels coated depressions and vesicles near the apical cell surface, numerous uncoated tubules and larger apical vesicles, and multivesicular bodies within trophoblast cells. Basally and laterally the labeled components are primarily small uncoated vesicles and tubules. Small, discrete clusters of ferritin particles were seen within the basolateral compartment between trophoblast and its basal lamina and beneath trophoblast cells that do not have a basal lamina. the results indicate that ingested materials may be directed in two pathways, one involving breakdown within the lysosomal system and one involving transcytosis. The zona pellucida is a trilaminar structure consisting of a fibrillar outer layer that often contains spermatozoa, an intermediate zone, and an inner layer containing columns of dense zonal material. Loss of the zona occurs after expansion of the blastocyst and development of the endocytic organelles. During the late blastocyst stage, syncytial trophoblast differentiates at the margin of the polar trophoblast. Because blastocysts were flushed from the uterus, it could not be determined whether azonal blastocysts had been adherent to the uterine surface prior to collection.

Loss of polar trophoblast during differentiation of the blastocyst of the horse.

Twelve blastocysts, collected 7-12 days after ovulation (Day 0), were examined by light and electron microscopy to investigate the nature of the relationship of the polar trophoblast (Rauber's layer) to the inner cell mass. On Day 7, the polar trophoblast was intact and formed a flattened layer overlying the epiblast cells of the inner cell mass. As blastocysts enlarged to greater than 1 mm in diameter, small discontinuities appeared in the polar trophoblast, where epiblast cells intruded onto the surface. At this time, trophoblast cells adhered closely to adjacent and underlying epiblast cells, forming an irregular layer of cells capping the epiblast. With continued increase in blastocyst size, polar trophoblast cells became isolated but maintained their characteristic apical endocytic structures. By Days 10-12, the scattered trophoblast cells showed evidence of deterioration, and vacuoles containing cell debris were common within the epiblast. It is suggested that polar trophoblast cells become scattered, rather than withdrawing as a unit, because they become more adherent to subjacent epiblast cells than to adjacent trophoblast cells. It is further suggested that most of the isolated cells are eventually phagocytosed by epiblast cells.

The ovulated ovum of the horse: cytology of nonfertilized ova to pronuclear stage ova.

Fertilization and early development in the horse were studied by recovering oviductal ova at various times after postovulatory mating. Ova collected between 7 and 22 h post coitum (pc) were examined for evidence of fertilizing sperm, cellular changes accompanying fertilization, and pronuclear development. Five ova collected between 7 and 9 h pc contained a marginal metaphase plate, but had no indication of sperm components; three of these, however, showed reduced numbers of cortical granules. Two activated ova (10 and 14 h pc) were in telophase of the second meiotic division, following incorporation of the fertilizing sperm. The fertilizing sperm was situated in a slight elevation; the nucleus was expanding but lacked a nuclear envelope. The pronuclear stage in the horse began as early as 12 h pc, and lasted at least until 21 h pc. Sperm tail remnants were seen in 5 of 7 pronuclear-stage ova, although the crowding of the cytoplasm with clusters of lipid and vacuoles made discerning sperm tail remnants difficult. The spindles of the metaphase stage of the second meiotic division were oriented radially, that is, at right angles to the cell surface, in all but one ovum, so this orientation is not a response to fertilization.

Differentiation of the embryonic disc, amnion, and yolk sac in the rhesus monkey.

The inner cell mass of the blastocyst has differentiated into epiblast and hypoblast (primitive endoderm) prior to implantation. Since endoderm cells extend beyond the epiblast, it can be considered that both parietal and visceral endoderm are present. At implantation, epiblast cells begin to show marked evidence of polarity. They form a spherical aggregate with their basal ends toward the basal lamina and apical ends toward the interior. The potential for an internal space is formed by this change in polarity of the cells. No cytological evidence of separation of those cells that will form amniotic epithelium from the rest of the epiblast is seen until a cavity begins to form. The amniotic epithelium is originally contiguous with overlying cytotrophoblast, and a diverticulum remains in this position during early development. Epiblast forms a pseudostratified columnar epithelium, but dividing cells are situated toward the amniotic cavity rather than basally. The first evidence of a trilaminar disc occurs when a strand of cells contiguous with epiblast is found extending toward visceral endoderm. These presumptive mesoderm cells are undifferentiated, whereas extraembryonic mesoderm cells are already a distinct population forming extracellular materials. After implantation, visceral endoderm cells proliferate forming an irregular layer one to three cells thick. Visceral endoderm cells have smooth apical surfaces, but very irregular basal surfaces, and no basal lamina. At the margins of the disc, visceral endoderm is continuous with parietal endoderm and reflects back over the apices of the marginal visceral endoderm cells. This sacculation by visceral endoderm cells precedes pinching off of the secondary yolk sac from the remaining primary yolk sac.

Morphological changes in the blastocyst of the western spotted skunk during activation from delayed implantation.

Blastocysts collected from the spotted skunk during delay of implantation, early activation and late activation demonstrate three-tiered growth and developmental changes. The slow-growing blastocyst from the several months of delay is small (less than 1.1 mm) with a rounded inner cell mass consisting of clusters of rounded, lipid-filled cells. During the several days of early activation, the lipid in both inner cell mass and trophoblast diminishes, polyribosomes increase in number, and the endodermal layer differentiates as the blastocyst grows (1.2-1.6 mm). At activation the inner cell mass flattens, becomes uncovered by polar trophoblast, and forms a disc of columnar epiblast cells. The blastocyst expands rapidly during the last 24-48 h prior to implantation to 1.7-2.0 mm, and the trophoblast becomes cuboidal with a marked endocytotic apparatus. The morphological evidence, together with previous studies of protein and RNA synthesis, suggests a tooling-up period during early activation with progressive increases in rates of growth and differentiation in the last hours as implantation approaches.

Penetration of the basal lamina of the uterine luminal epithelium during implantation in the rat.

During early stages of implantation in the rat, as in other species that form a hemochorial placenta, there is a progressive increase in intimacy between blastocyst and endometrium. After initial invasion of the uterine luminal epithelium by trophoblast cells and displacement of epithelial cells, the trophoblast comes to lie adjacent to the residual basal lamina of the displaced epithelium but does not penetrate it. After a pause at the basal lamina, this temporary barrier is breached. To study the interrelations of trophoblast, uterine epithelium, and decidual cells with the epithelial basal lamina during the time of penetration of the basal lamina, implantation sites collected on day 7 of pregnancy were oriented so that the implantation chamber could be sectioned either longitudinally or transversely. Neither trophoblast nor uterine epithelial cells have processes that extend through the basal lamina. However, flange-like processes from the decidual cells penetrate the basal lamina and underlie both trophoblast and, more rarely, epithelium. Smaller folds of the surface of decidual cells partially surround bundles of collagen fibrils oriented parallel to the long axis of the implantation chamber. Initially the area of penetration of basal lamina by decidual cell processes is quite restricted; as implantation proceeds the basal lamina becomes displaced and is sometimes not discernible, extracellular materials accumulate, and the relationships become more difficult to follow. It is concluded that the initial breaching of the basal lamina is an activity of the decidual cells, and that contact of basal lamina with trophoblast is not necessary to permit this penetration.

Implantation in the rhesus monkey: Endometrial responses.

In this continuing series of studies of implantation in the rhesus monkey, eight specimens, ranging in gestation age from 9.5 days to 16.5 days after ovulation, were examined with a focus on localized modifications in the endometrium as a response to implantation. Additionally, evidence of continuing changes in early pregnancy was provided by three specimens at the end of the first month of gestation (days 24, 28, and 35). The responses of the endometrium to pregnancy start with a localized accumulation of stromal eosinophils, which is rapidly followed by epithelial plaque formation in the basal cells of the luminal epithelium and gland necks. Plaque cells hypertrophy, develop marginal dense granules, and accumulate glycogen. They form a pad underlying the margins but not the central zone of the implantation site. However, some degenerating plaque cells are found as early as day 15; and little more than a region of leukocytic infiltration remains of the plaque by day 35. Shortly after the plaque response is initiated there is a striking subepithelial edema surrounding the plaque, and the venular capillaries enlarge by engorgement and by endothelial hyperplasia. The endothelial cells subsequently hypertrophy, resulting in a largely columnar endothelium. There is a localized decidual cell response, consisting of an increase in rough endoplasmic reticulum and in filaments, but only a moderate amount of hypertrophy of these cells. Endometrial granular cells become more conspicuous in the area as they accumulate glycogen. Patches of large pale cells appear in the lumen and walls of arterioles subjacent to the implantation site, but the cytology of these cells provided insufficient clues to their origin (cytotrophoblast?). Although the endometrial responses described are impressive and diverse, their advantages to the organism are not obvious. The hypertrophy of the anastomotic capillary bed that accompanies plaque formation may well provide an extensive vascular network available to the developing trophoblastic lacunae. The role of endometrial granular cells, decidual cells, and even plaque cells may be more related to their largely unexplored secretory activity than to their physical contribution to the formation of the basal plate.

Trophectoderm cell subpopulations in the periimplantation mouse blastocyst.

Trophectoderm of the preimplantation mouse blastocyst is composed of two cell subpopulations relative to their proximity to the inner cell mass. The polar trophectoderm overlying the inner cell mass proliferates to form the ectoplacental cone, and the mural trophectoderm endoreplicates and gives rise to giant cells. We examined specific differences in the two trophectoderm cell populations using a lectin (Dolichos biflorus) to detect cell surface characteristics and a simple sugar (D-Gal) to detect differences in incorporation. During the first day of delayed implantation, the mural trophectoderm presented twice as many lectin binding sites as did the polar trophectoderm. The mural trophectoderm of both nondelaying and delayed implantation blastocysts showed a greater rate of incorporation of the tritiated sugar by presenting more reduced silver grains in radioautograms. These results indicate that the mural trophectoderm and polar trophectoderm are two distinct cell types in the periimplantation blastocyst.

Implantation in the rhesus monkey: initial penetration of endometrium.

A series of peri-implantation stages of the rhesus monkey has been collected; these range from preimplantation blastocysts through initial implantation to early villus formation. The three earliest postimplantation specimens encompass the stages of penetration into and through the uterine luminal epithelium and into endometrial blood vessels. The day of pregnancy was established by radioimmunoassay of estrogen (E) levels to determine the preovulatory E peak, and in each instance the embryo was examined to determine the extent of development. The conceptus collected on day 9.5 of pregnancy was the earliest implantation stage; it ballooned above a depression in the endometrium to which it was firmly attached. A column of syncytial trophoblast penetrated into the uterine epithelium to the basal lamina of the latter. The syncytial trophoblast shared junctional complexes with the uterine epithelial cells to which it was apposed at the margin of the site of epithelial penetration. Basal to the apical junction complexes, processes of syncytium indented uterine epithelial cells. Several epithelial cells had been partially isolated and surrounded by flanges of syncytial trophoblast. In the next specimen, at 10.0 days after ovulation, the uterine epithelium had initiated the epithelial plaque reaction. The trophoblast had extended along the residual basal lamina of the uterine epithelium and into the neck of an adjacent uterine gland. Cytotrophoblast was abundant in the central region of the implantation site, and was intermixed with syncytium which formed the majority of the peripheral trophoblast. In several places clefts had formed in the syncytial trophoblast; these clefts were lined with microvilli, had intermicrovillous caveolae, and consequently more closely resemble the trophoblast that eventually lines the intervillous spaces than the trophoblast involved in initial invasion. In the day-10.5 specimen, in addition to prelacunar clefts, lacunae containing maternal blood were present for the first time. The basal lamina was penetrated in many places, and syncytial trophoblast was interposed between maternal endothelial cells of the underlying vessels. It was concluded that syncytial trophoblast is the first tissue to penetrate the uterine luminal epithelium; that the basal lamina of the uterine luminal epithelium, but not the basal lamina of endothelium, constitutes a temporary barrier to trophoblast penetration; that invasion is accomplished with less destruction of maternal tissue than previously suggested; and that the rapid superficial growth of the placenta is made possible by the early tapping of the endometrial vessels.

Differentiation of the Blastocyst of the rhesus monkey.

A method of flushing the oviduct and/or uterus of rhesus monkeys was used to obtain a number of preimplantation stages, of which four cleavage stages and seven blastocysts that were judged to be normal were studied cytologically using transmission electron microscopy. In addition to the usual changes in mitochondria and endoplasmic reticulum that accompany differentiation of the blastomeres, the blastocysts with zonae showed sequestration of areas of cytoplasm. The first indications of junctional complexes were short stretches of parallel membrane with a slightly increased density found in the morula stage. Blastocysts developed typical apical junctional complexes, but in addition showed extensive gap junctions linking trophoblast and inner cell mass, and epiblast and differentiating endoderm. Endodermal differentiation occurred at about the same time that a basal lamina was found under mural trophoblast and epiblast (but not polar trophoblast or endoderm). Enlarged torn zonae were found in association with one blastocyst and unaccompanied by blastocysts, including a case in which the animal subsequently prove to be pregnant. This observation suggests that hatching is a normal feature of zonal escape in this species. The trophoblast of blastocysts without zonae had well-formed apical absorptive areas and, in some instances, long irregular microvilli in the area near the inner cell mass. Cell debris, vacuoles containing debris and isolated cells, although variable, were common features of the preimplantation stage in the rhesus monkey.

Cytology of the endometrium of delayed and early implantation with special reference to mice and mustelids.

Although it is apparent that the uterus is involved in the control of embryonic diapause, in no instance do we know the precise nature of that control. The most direct control would be through synthesis of proteins or other macromolecules by the uterus itself. Whereas luminal contents have been shown to vary significantly near the time of implantation, neither the role of the luminal fluid constituents, nor the cellular origins of these molecules are fully known, nor have the mechanisms of storage and secretion of proteins in the endometrium been fully established. Cellular structures that may be indicative of functional activity include secretory granules or vesicles, increase or dilation of granular endoplasmic reticulum and increase in size, and associated vesicles of the Golgi complex. Storage of glycogen or lipid appears more indicative of lowered activity. However, despite striking changes in these cytological characteristics in different animals during delay and early implantation, there is no single pattern during the delay period, and no predictable alteration in the peri-implantation period. In general, the structure of the uterus of an animal during delay resembles a modification of that of a closely related species that does not delay more than it resembles that of other species that do show delay.