PubMed Health⌕ Search

Biomedical subjects

U M Spornitz

Publications and source records attributed to U M Spornitz.

At least 19 recordsLinked to original sources
PubMed1992

The functional morphology of the human endometrium and decidua.

The functional morphology of the human endometrium and decidua has been investigated with particular attention to all aspects of implantation and contraception. The postovulatory triad (of glandular epithelium), comprising subnuclear glycogen, giant mitochondria, and the NCS seems to be involved in both implantation and contraception and has been studied in detail. Initial stages of glycogen formation were found to be related to straight, uncoiled forms of polysomes which, by acting as acceptor molecules for glucose start glycogen synthesis. Discharge of glycogen from the glandular epithelium is achieved by a type of apocrine secretion. Computer-aided reconstruction of giant mitochondria, based on ultra-thin serial sections, revealed that giant mitochondria of the secretory phase of the cycle are not comprised of a single complex mitochondrion, but of numerous single mitochondria. Towards the end of the cycle, these mitochondria either reduce their size to normal by means of budding of protrusions or they are degraded in autophagic vacuoles. The NCS was studied for the first time from the initial stages of formation to the final stages of intracellular degradation. Based on ultra-thin serial sections the NCS was reconstructed with manual and computer-aided reconstruction. It was found to consist of seven sets of tubules, each containing three rows of coiled tubules which are wound in one-and-a-half turns from the site of origin at the nuclear membrane to the karyoplasmic pole. The individual tubules are interconnected by means of lacunae or connecting tubules. The formation of the NCS is suppressed by progesterone IUDs, but not by copper IUDs, and it is not formed in anovulatory cycles or under low-dose gestagen therapy (Minipill). The NCS is believed to participate in regulatory mechanisms of the glandular epithelium. Thus, the contraceptive action of the progesteroneIUD may in part be due to the suppression of the NCS and not only due to decidualization of the endometrial stroma. From the middle to late secretory phase K cells (endometrial granulocytes) and predecidual cells are formed. Their development and ultimate fate was studied during the normal physiological cycle, under a progesterone IUD, and also during pregnancy. K cells do not develop from stromal fibrocytes, as has been postulated in the past, but from lymphocyte-like cells which are present in the endometrium after ovulation. These cells multiply through mitotic division within the endometrial stroma. Under a progesterone IUD and during pregnancy they discharge their secretory granules and reduce their size drastically by giving off glycogen-containing cytoplasmic patches.(ABSTRACT TRUNCATED AT 400 WORDS)

Decidua↗
PubMed1992

Liver architecture.

The development of liver parenchyma starts from entodermal cells which grow out from the gut into the mesenchyma of the septum transversum. In the definitive organ this close association of epithelial cells (hepatocytes) and mesenchyma-derived nonparenchymal cells is maintained. The liver, and with it each hepatocyte, acts in two directions: the vascular poles of the hepatocytes serve in an ingestive sense, while at their biliary poles secretory functions are exerted. Hepatic microvascularization comprises two afferent vessels (arterial and portal terminal branches), the sinusoids and the terminal hepatic venule. Sinusoidal cells surround the capillaries but also have highly specialized functions with regard to filtration, phagocytosis, fat storage and defense. The autonomic innervation plays an important role in the regulation of metabolic functions. Above the cellular level the proper architecture of the liver parenchyma has been the object of controversial discussions for centuries. The concept of the liver lobule, the portal unit, the liver acinus and other structures are presented and discussed. Finally, the liver parenchyma is described as an irregular interdigitating system of regions related to the terminal blood vessels.

Animals↗
PubMed1991

Microarchitecture of the human endometrium by scanning electron microscopy: menstrual desquamation and remodeling.

Twenty-two hysterectomy specimens were collected over a period of two decades in order to investigate the morphological sequence of menstrual desquamation and its consecutive remodeling of the endometrium. The technique used was described earlier by H. Ludwig and H. Metzger (1976). Scanning electron microscopy is the only way to illustrate and describe the microarchitecture of the endometrial surface. At the beginning of the menstrual bleeding, glandular stumps surviving the desquamation of the layer functionalis stick out from the debris at the top of the basal layer. Fibrin mesh formation, the liberation of lysosomes, and the emigration of white blood cells and macrophages, both being already present in the midluteal endometrial stroma, can be observed. They are interrelated with the clearance of the menstrual wound. Coincidentally with the process of desquamation the re-epithelization starts and takes the first four to six days of the normal cycle. The events are illustrated by selecting specimens of uteri from women with comparable data but from different days of the normal cycle. Surprisingly transitory excess formation of epithelial outgrows (micropolyps) are observed. They disappear later in the cycle, some might persist and form micropolyps, which will be the source of occasional intermenstrual bleeding--so far the polyps are vascularized. The endometrial surface is covered de novo by a lining surface epithelium at the sixth day. Ciliogenesis occurs within this epithelium. Other ciliated cells emanate from the glandular epithelium. In early stages of menstrual regeneration the growth pattern of the epithelial monolayer forming the lining surface in spiral traces according to their origination from the circle-structures of the endometrial glands. Before the incoming menstrual break-down small crevices, clefts or defects appear within the lining surface endometrium, a few white blood cells, enriched in the stroma around the vessels, might even reach the surface. The apical membranes of several non-ciliated cells exhibit rounded leaks, others show ruptures. It is the tissue break-down around the superficial endometrial vessels, what creates the onset of menstrual blood flow. In the very early preparations of the bleeding endometrium those opened capillary vessels could be identified.

Cell Cycle↗
PubMed1989

Scanning microscopy of the developing vagina in postnatal gerbils.

Scanning electron microscopy of postnatally developing gerbil vagina (birth to maturity) shows that longitudinal folds form prior to transverse folds; the process of fold formation is initiated on the dorsal wall and proceeds ventrally. From days 1 to 7 postnatally, the vaginal epithelium is composed of either flat or bulging cells, depending on the vaginal region. The luminal cell surface is covered with uniform stubby microvilli and solitary cilia. Between days 9 and 20, the flat cells with distinct cell boundaries spread toward more proximal areas, leading to the formation of mixed patches of cells with flat or rounded apices. Individual elongated microvilli or tufts of forked microvilli may sprout from their surfaces. Solitary cilia gradually disappear. The transition from immature to mature vaginal epithelium starts around day 20, when individual cells recess below the level of neighboring cells. This process spreads throughout the vagina during the following days, reflecting local changes in the subsurface layers of the epithelium preparatory to exfoliation. Around day 40 the actual exfoliation of the luminal cell layer starts. By this time the surface characteristics of many of the desquamating cells have changed. In addition to microvilli, microridges are being formed. The process of exfoliation is finished by about day 60. The newly appearing cell layers now transform into typical cornified cells of the cycling vaginal epithelium.

Animals↗
PubMed1977

Morphologic alterations in the epithelium of the human oviduct induced by a low dosis gestagen.

Morphological alterations in the epithelium of the human oviduct related to continuous administration of low dosage lynestrenol were studied in 10 women by electron microscopy. The effect of lynestrenol on the morphology of the tubal epithelium was shown to be time dependent. First the discharge of secretory products from the non-ciliated cells was inhibited. Secondary to this the synthetic activities of the cells were drastically decreased. This inactivation of the tubal epithelium reached its maximum after 6 months. At this time the epithelial cells, particularly the non-ciliated cells were almost devoid of organelles and had an electron transparent cytoplasm. In addition to the action of lynestrenol on the secretory and synthetic activities of the cells a strong ciliogenetic effect could be observed after about 3 months of lynestrenol administration. The ratio of ciliated to non-ciliated cells changed from 1:1 at the beginning of the treatment to 2.9:1 after 6 months. This ratio was then maintained and could still be found in patients who had used lynestrenol for 25 and 39 months. In contrast to the persistent effect of lynestrenol on the ciliary apparatus of the cells the synthetic activities and the secretory mechanism were partially restored with long standing use. The importance of the observed changes and their possible participation in the contraceptive action of lynestrenol are discussed.

Adolescent↗
PubMed1976

[The low dosis gestagen therapy (author's transl)].

In young women aged 22-34 years the hormone profile under continuous therapy with 0.5 mg lynestrenol/day have been investigated. Estradiol, progesterone and FSH values have been determined in plasma by the RIA or protein-binding method, whereas LH excretion was daily measured in the urine starting on the 5th day of cycle. The low-dose-gestagen therapy shows all possible hormonal patterns ranging from the ovulatory to anovulatory one. The estradiol-17 B values in half of the patients were higher than in the cycle preceding treatment. In the first few treatment cycles all women showed markedly decreased progesterone values. However, this defect seems to recover and return to normal in later cycles. In order to be able to further explain the alterations occurring during the luteal phase under the treatment with 0.5 mg/day of lynestrenol, ovarian tissues wedge resection of women undergoing gynecological surgery has been examined macroscopically and microscopically. At the same time the hormonal profile has been determined in plasma. These investigations revealed that the morphological alterations in the ovary proceed in an unchanged way under the mentioned treatment. Histologically it could be demonstrated that ovulation is delayed by several days. The histological findings of tubal tissue (from patients who underwent sterilization) showed that the secretional activity of the tubal epithelium is considerably decreased and ciliogenesis increased. In our clinical study neither tablet nor patient failures occurred. With the exception of cycle- and tempo-disturbances no severe adverse reactions were reported. Breakthrough bleedings and spotting as well as amenorrhea in most cases manifested already in the first treatment cycles. It is important that the daily tablet is taken at midday because the maximum effect on the cervical mucus of the mini-pill therapy is most pronounced 4-6 hours after tablet intake. Especially in young patients it is recommended to get written reports on tablet intake. The strict following of these directions mainly guarantees a successful mini-pill therapy.

Adult↗
PubMed1975

Studies on the liver of Xenopus laevis. I. The ultrastructure of the parenchymal cell.

The liver of Xenopus laevis was examined with electron microscopy. Its structure was found to be markedly different from that of mammals, particularly regarding the morphology of the hepatocytes to be classified as typical. It was established that the main function of such a cell is the storage of glycogen, and further that it possesses only scant organelles and other inclusions. Since this type of cell was found most frequently in the liver of untreated animals, it was designated as normal cell. The fact appears noteworthy that in the normal liver of Xenopus laevis an abundance of cell types occur which are otherwise found to be proliferated under experimental conditions, e.g. cells with pronouncedly augmented RER, enlarged Golgi complexes, increased lipid inclusions etc. This high number of divergent hepatocytes and the fact that all intermediate stages between the individual extremes are present and not to be accounted for by the position of the cell within the liver was interpreted as being the expression of a cyclic passage of the various stages of activity. It is of special interest that augmented degradation of glycogen in the liver cell takes place only during vitellogenesis. Acute and chronic hunger, as well as adaptation to cold, hardly affect the morphology of the normal cell, especially as far as the glycogen is concerned. The possible causes for this are discussed.

Animals↗
PubMed1975

Studies on the liver of Xenopus laevis. II. The ultrastructure of the peritoneal cover and the perihepatic layer.

The peritoneal cover and the subcapsular region of the liver of Xenopus laevis were examined with electron microscopy. In the subcapsular region a prominent perihepatic layer two to ten cells wide was found. This perihepatic layer is mainly composed of granulocytopoietic tissue. Other cell types found in the perihepatic layer were lymphocytes, pigment cells and fat storing cells. The presence of a perihepatic granulocytopoietic layer in the liver of Xenopus laevis is in contrast to current opinion that such a layer is a characteristic typical of urodeles. The phylogenetic significance of such a layer in anurans and the developmental processes of the individual cell types of the perihepatic layer are discussed. Furthermore the possible participation of the perihepatic layer in the immune response is considered.

Animals↗