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PubMed1979

[Ligation of the yolk sac circulation and its effect on the yolk sac ultrastructure and development of the rat fetus].

The effect of an interruption of the yolk sac circulation on the rat visceral yolk sac and the development of the fetoplacental unit was examined in the last third of pregnancy. The yolk sac ischaemia was induced by ligating the blood vessels of the yolk sac stalk which connect the vitelline circulation with that of the fetus. A 3-hour ligature caused an extensive swelling of most cell organelles in the epithelial cells and in the capillary endothelia of the yolk sac. Other structural changes were indicative of a cessation of pinocytosis. A 6-hour ligature resulted in a common increase of cell swelling and in a beginning disintegration of the endothelial cells lining the vitelline capillaries. A 15-hour ligature caused severe ultrastructural cell lesions and macroscopical alterations suggestive of a progressive necrolar finding of a nearly complete loss of the amniotic fluid and the death of the fetus, although the maternal blood flow appeared to be still intact in the placenta.

Amniotic Fluid↗

PubMed1981

[An ultrastructural study of human ovarian yolk sac tumor--an investigation of its histogenesis compared to that of human yolk sacs (author's transl)].

For the purpose of investigating the histogenesis of the yolk sac tumor, 7 cases of the tumor and 9 cases of human yolk sac were used. Histological, ultrastructural investigations together with immunofluorescent antibody examinations revealed the following results. Ultrastructurally yolk sac endodermal cells prior to the 7th week of pregnancy were proved to have microvilli, abundant glycogen which formed rosette, parallel arranged rough endoplasmic reticulum (rER), mitochondria closely associated with rER and ovoid electron dense amorphous granules which showed positive diastase-resistant PAS-reaction. Morphologically endoderm after the 8th week of pregnancy showed degenerative changes. Light microscopically the tumors showed Schiller-Duval body, endodermal sinus structure and clear-cells endoblastic pattern, but ultrastructurally the tumor cells of these three types showed approximately similar appearances. Ultrastructural features of the tumor seem to resemble those of the yolk sac endoderm before the 7th week of pregnancy. The tumor cells which form the epithelial mantling of Schiller-Duval body closely resembled the endodermal cells facing the yolk sac cavity with respect to the presence of abundant glycogen granules, rER, mitochondria, short irregular microvilli on the cell surface and remarkable nucleolus with thread-like nucleolonema. Both the tumor cells facing the endothelial cell and those which form the endodermal sinus structure and clear-cells endoblastic pattern resembled the endodermal cells facing the mesenchyma in view of the features of intracellular organelles, the presence of extracellular basement membrane-like substances and tubular structure.

Adolescent↗

PubMed1984

Transformation of an AFP-positive yolk sac carcinoma into an AFP-negative neoplasm. Evidence for in vivo cloning of the human parietal yolk sac carcinoma.

An alpha-fetoprotein (AFP)-positive ovarian yolk sac carcinoma of typical histologic appearance was surgically removed from a 19-year-old woman. The AFP-positive tumor recurred and was treated with x-rays and cytotoxic drugs to full remission, i.e., until no clinical or biochemical signs of tumor were evident. The second recurrence, which proved to be fatal, was noticed approximately 1 year after the initial diagnosis, but was not associated with elevated levels of serum AFP. At autopsy, the widespread tumor had the histologic appearance reminiscent of murine parietal yolk sac (PYS) carcinoma. The tumor cells did not form the characteristic histologic features of the classical human yolk sac carcinoma, did not secrete AFP, and were surrounded by extensive hyalinous extracellular matrix rich in laminin and collagen. It is thus shown that recurrent human yolk sac carcinomas could change their histologic morphology due to selective outgrowth and cloning of the parietal yolk sac component. Clinical recognition of this cloning is important because the PYS carcinoma cells do not secrete AFP, and the tumor growth cannot be biochemically monitored with this classical tumor marker.

Adult↗

PubMed1995

Expression of gamma-glutamyl transpeptidase in midgestation mouse yolk sac and mouse visceral yolk sac carcinoma cells.

gamma-Glutamyl transpeptidase (gamma GT) is a crucial enzyme for the metabolism of xenobiotics and endogenous mediators of biological functions (leukotrienes, prostaglandins, and hepoxillins). Yet little is known about its potential role during development. It is a single copy gene expressed from at least seven promoters. Using histochemistry and immunohistochemistry we demonstrate that gamma GT first appears in the midgestational yolk sacs of mouse embryos. Established cell lines with phenotypic features of yolk sac endoderm (JC-44) or embryonic stem cells were also assayed for the expression of gamma GT. Significant levels were detected in JC-44 cells and higher levels were found in JC-44-derived embryoid bodies. Because this cell line appears to be a good in vitro counterpart of yolk sac differentiation, we characterized the gamma GT mRNA types expressed in JC-44 cells. By ribonuclease protection analysis, gamma GT RNA types IV and VI represent about 80% of the total gamma GT RNA in JC-44 embryoid bodies. Reverse transcription-mediated polymerase chain reaction detected low amounts of gamma GT RNA types I, III, and V. Expression of gamma GT in yolk sac follows a pattern seen in many tissues in which one or two gamma GT RNA types dominate the expression profile; however, the reason for this tissue specificity is unknown.

Animals↗

PubMed1976

The human yolk sac and yolk sac carcinoma. An ultrastructural study.

The ultrastructure of the yolk sac of a 39 day old human embryo was studied. The subcellular organization was suggestive of a highly specialized absorptive function proceeding in an exocelomic-viteline direction. These findings, compatible with intense metabolic activity, are at variance with the concept of rapid involution of the yolk sac following completion of its hemopoietic and angiogenetic functions. The speculation is advanced that a potential avenue exists in the yolk sac whereby maternally derived products encounter fetal endoderm. Ultrastructural features in the normal yolk sac were compared to those existing in a tumor showing the "endodermal sinus" pattern, and reviewed in the light of the pertinent literature. These findings support the concept that attributes an endomesoblastic derivation to such neoplasms.

Dysgerminoma↗

PubMed2000

Clinical stage I pure yolk sac tumor of the testis in adults has different clinical behavior than juvenile yolk sac tumor.

PURPOSE: We evaluated the clinical behavior of clinical stage I pure yolk sac tumor of the testis in adults to determine whether the behavior of this entity is different than that of clinical stage 1 nonseminoma. MATERIALS AND METHODS: We searched the testis cancer database at our institution for adults with clinical stage I pure yolk sac tumor of the testis who underwent retroperitoneal lymph node dissection. We identified 12 such patients and reviewed the database and hospital charts to determine clinical behavior. RESULTS: Disease was pathological stage I in 8 of the 12 patients (66%), including 1 with recurrence after retroperitoneal lymph node dissection. Disease was pathological stage II in 14 patients (33%), including 1 who remains disease-free after electing adjuvant bleomycin, etoposide and cisplatin. Of the 3 patients who elected observation after retroperitoneal lymph node dissection only 1 has had recurrence, while 2 (66%) were cured by retroperitoneal lymph node dissection only. CONCLUSIONS: Contrary to juvenile yolk sac tumor, which has a strong tendency toward hematogenous metastasis, the behavior of clinical stage I adult pure yolk sac tumor is similar to that of all other stage I nonseminomas in adulthood.

Adolescent↗

PubMed1989

The endolymphatic sac and inner ear homeostasis. I: Effect of glycerol on the endolymphatic sac with or without colchicine pretreatment.

The combined effects of glycerol and colchicine on the endolymphatic sac were investigated in mice. Glycerol induced signs of secretion from the epithelium with formation of secretory granules in the light epithelial cells. Other characteristics of the epithelial lining were also changed resulting in an increased widening of the lateral intercellular spaces, a partial collapse of the lumen and with a deposition of a stainable substance within the lumen. This reaction lasted from 30 min to 24 h following the injection. Pretreatment with colchicine was found to decrease or inhibit the glycerol-induced secretion of macromolecules into the sac. The lumen collapsed but frequently there was no presence of stainable substance. Animals treated with both glycerol and colchicine showed marked signs of inner ear malfunction which could indicate that the secretory activity in the sac might be closely related to the regulation of inner ear fluid homeostasis and that functional disturbances in this system may lead to disorders of inner ear function.

Animals↗

PubMed1979

Lymphocyte-macrophage activity in the endolymphatic sac. An ultrastructural study of the rugose endolymphatic sac in the guinea pig.

The irregular epithelial layer which delimits the intermediate part of the endolymphatic sac, and the surrounding perisaccular tissue, were examined morphologically in the guinea pig by transmission electron microscopy. Specialized areas of the epithelium which have previously been designated as "non-vascularized epithelial processes" (NVP) were constantly observed. These proliferative areas showed a close topographical relation to the free luminal cells and contained an abundance of lymphoid cells. Lymphocytes and macrophages were intimately associated with each other in a manner similar to that seen in these two types of cells in antigen-stimulated lymphoid tissues. There was a marked degeneration and phagocytosis of cells. The richly vascularized perisaccular tissue was rich in plasma cells, monocytes, mast cells and lymphocytes. The latter could be seen to migrate through the endothelial cells in the thin post-capillary venules into the sac tissue. The authors consider that the endolymphatic sac plays a role as an immunological defence organ for the internal ear. A hypothetical model concerning circulation and turnover of certain of the free intraluminal cells in presented.

Animals↗

PubMed1977

An in vitro morphological study of the mouse visceral yolk sac and possible yolk sac immunocyte precursors.

Mouse visceral yolk sac has been organ cultured from 9 days of gestation, a time prior to the thymus being lymphoid, until 12 days of gestation, a time after which the thymus is lymphoid. During the culture period the endodermal epithelial cells survived well, erythropoiesis diminished, endothelial-lined cavities formed in the mesodermal mass, and cells developed which have been classified as large, medium and small immunocyte precursors. The cytoplasm of the immunocyte precursors contains polysomes, spherical mitochondria, a few profiles of rough endoplasmic reticulum, occasional granules and a large Golgi complex. This study offers morphological support for the yolk sac origin of immunocyte precursors in the mouse which may seed the thymus and liver.

Animals↗

PubMed1992

Growth of a human yolk sac tumor cell line with yolk sac-derived functions in selenium-supplemented chemically defined synthetic medium.

A human yolk sac tumor cell line, TG1, which was established from a testicular yolk sac tumor, was found to replicate continuously in a chemically defined medium supplemented with Na2SeO3 (ISRPMI). TG1 produced several plasma proteins and growth factors: albumin, alpha-fetoprotein (AFP), ferritin, carcinoembryonic antigen, beta-2-microglobulin, polyamine, neuron specific enolase, tissue polypeptide antigen, transferrin (Tf), epidermal growth factor, and platelet derived growth factor. By analysis of lentil lectin (LcHA)-affinity electrophoresis, to examine the microheterogeneity of carbohydrate chains of synthetic glycoproteins, TG1 cells cultured with ISRPMI produced only LcHA reactive Tf and AFP based on core fucose attached to asparagine-linked N-acetylglucosamine residues instead of LcHA-nonreactive Tf and AFP produced by TG1 cells cultured with fetal bovine serum (FBS)-containing medium. alpha 1-6 Fucosyltransferase activity was significantly greater in the TG1 cells cultured with ISRPMI (39.9 +/- 1.5 pmol.h-1.mg-1 protein) than cultured with FBS-containing media (18.2 +/- 1.2 pmol.h-1.mg-1 protein). These results have indicated that the selective increase of alpha 1-6 fucosyltransferase occurred when the cells were cultured with the FBS-free synthetic media.

Carcinoembryonic Antigen↗

PubMed2006

SAC and SAC-CI calculations of excitation and circular dichroism spectra of straight-chain and cyclic dichalcogens.

Accurate quantum-chemical calculations of the excitation energies and the rotatory strengths of dichalcogens R-Ch-Ch-R (Ch = S, Se, Te) were carried out with the symmetry adapted cluster (SAC) and SAC-configuration interaction (CI) methods. A series of straight-chain molecules (dihydrogen dichalcogenide, dimethyl dichalcogenide, and (+)-bis(2-methylbutyl) dichalcogenide) and one cyclic molecule (2,3-(R,R)-dichalcogenadecalin) were adopted for comparative analysis. The calculated excitation and circular dichroism (CD) spectra were in good agreement with experimental ones (Laur, P. H. A. In Proceedings of the Third International Symposium on Organic Selenium and Tellurium Compounds; Cagniant, D., Kirsch, G., Eds.; Universite de Metz: Metz, 1979; pp 219-299) within 0.3 eV. The fitting CD spectra also reasonably reproduced the experimental ones. In all the molecules adopted, the first and second lowest bands were assigned to the n-sigma(Ch-Ch) transition and the third and fourth lowest bands to the n-sigma(Ch-R) transition. The first and second lowest bands apparently depended on the R-Ch-Ch-R dihedral angle, suggesting that the orbital energies of two sigma(Ch-Ch) change with the R-Ch-Ch-R dihedral angle. This calculated trend agrees with two empirical rules: the C(2) rule and the quadrant rule.

Chalcogens↗

PubMed2002

Epiphora due to compression of the lacrimal sac by a supernumerary blind sac.

A 23-year-old male had suffered from epiphora in the left eye since childhood. There was no history of infection or trauma. A supernumerary punctum was seen in the left lacrimal caruncle on examination. Subsequent dacryocystography and computer tomography showed a blind-ended sac that was connected to the supernumerary punctum, but not to the normally developed nasolacrimal system. When distended with secretion, this blind-ended lacrimal sac caused compression and obstruction of the normal lacrimal drainage pathway, which led to epiphora. The epiphora disappeared after surgical removal of the supernumerary system.

Adult↗

PubMed1982

Ultrastructural analysis of endolymphatic sac biopsies. Biopsy technique and identification of endolympathic sac epithelium.

This study describes the technique and instrumentation necessary to perform a double-wall biopsy of the endolymphatic sac (ELS). Since this technique protects the lumen of the ELS, which is within the center of the biopsy sample surrounded by the lateral and medial wall, the ultrastructure of the ELS epithelium, luminal contents, and perisaccular connective tissue tends to represent the in vivo status. The biopsy specimen can be analyzed by electron microscopy for clinical-pathologic correlation. Ultrastructural analysis (1) provides definite identification of the ELS and epithelium, (2) may provide insight into a possible role of the ELS in the pathogenesis of endolymphatic hydrops, and (3) can provide much improved clinical-pathologic correlation over only light microscopic studies.

Biopsy↗

PubMed1987

Effects of high intensity pure tone stimulation on the endolymphatic sac. Correlations between cochlear morphology and endolymphatic sac response.

A systematic study of the effects of acoustic overstimulation on the endolymphatic sac (ES) in the guinea pig was performed. The ES was studied with light and transmission electron microscopy after exposure of the animals to a 3.85 kHz pure tone of 108 dB SPL or 120 dB SPL for 22.5 min (sound energy 9.4 and 150 Pa2 X h, respectively). The damage pattern in the organ of Corti was studied after various post-exposure times with SEM and correlated with the morphological characteristics of the ES in the same ear. This was made possible by using a modified technique for histological processing. In ears with induced structural abnormalities to the organ of Corti, the ES displayed few morphological changes without obvious signs of accumulation of cell debris within the lumen. Initially an increase in the amount of freely floating cells was found which persisted for at least 24 h. The role of the ES for disposal and digestion of locally produced degeneration products within the cochlea after acoustically generated structural damage is discussed.

Acoustic Stimulation↗

PubMed1998

The non-specific effect of endolymphatic sac surgery in treatment of Meniere's disease: a prospective, randomized controlled study comparing "classic" endolymphatic sac surgery with the insertion of a ventilating tube in the tympanic membrane.

A prospective, randomized study was carried out comparing the effect of two surgical modalities in the treatment of patients with Meniere's disease: insertion of an endolymphatic sac shunt and insertion of a ventilating tube in the tympanic membrane. A total of 29 patients, 12 males and 17 females, age 27-71 years, were operated on in two ear, nose and throat (ENT) departments. Of these patients, 15 had an endolymphatic shunt inserted and 14 had a ventilating tube inserted in the tympanic membrane. Postoperative follow-up was carried out in the department in which the patients had not been operated. The severity of the disease was scored pre- and postoperatively, and the results evaluated under the guidelines of the Committee on Hearing and Equilibrium (1995) for the diagnosis and evaluation of therapy in Meniere's disease. The patients in both groups had a statistically significant reduction in dizzy spells, measured 6 and 12 months postoperatively, and there was no difference between the groups. The pathophysiological explanation for the reduction in dizzy spells in each of the treatment modalities is debatable and the effect is non-specific. The patients' hearing and tinnitus were statistically unaffected by the treatment in both groups, though 2 patients in the shunt group developed severe hearing loss (anacusis/70 dB).

Adult↗

PubMed1992

Osmotically induced macrophage activity in the endolymphatic sac. On the possible interaction between periaqueductal bone marrow cells and the endolymphatic sac.

This study aimed to investigate the origin of the free cells in the lumen of the endolymphatic sac (ES). Activation of the cells was accomplished through osmotic induction using glycerol. The ES and the perisaccular tissue were analyzed with special reference to the activity of periaqueductal bone marrow cells after different time intervals following the injection of hyperosmotic agents. The results show that the perisaccular or periaqueductal bone marrow space may constitute a source of some of the free cells occurring in the ES. Osmotic challenging of the inner ear may cause activation of the periaqueductal bone marrow, initiating the locomotion and migration of cells (mostly monocytes, neutrophils and eosinophilic leukocytes) along bone marrow sinusoids that frequently anastomose with the ES vessels. The free cells show signs of transepithelial diapedesis and, in the lumen of the ES, cells may develop into phagocytes which initiate the ingestion and degradation of secreted macromolecular aggregates. It is thought that osmotic alterations in the inner ear may give rise to local changes in or around the ES, leading to the chemotactic attraction of bone marrow cells. The results verify the existence of a complex sugar/protein aggregate metabolism over the wall of the ES, which is linked to the turnover of free cells. The findings may indicate that ES macrophages are important in the regulation of inner ear fluid homeostasis.

Animals↗

PubMed2000

MR imaging of the enlarged endolymphatic duct and sac syndrome by use of a 3D fast asymmetric spin-echo sequence: volume and signal-intensity measurement of the endolymphatic duct and sac and area measurement of the cochlear modiolus.

BACKGROUND AND PURPOSE: In enlarged endolymphatic duct (EED) and sac (EES) syndrome, deformity of the EED and EES is congenital; however, hearing loss is acquired. To investigate the pathophysiology of progressive sensorineural hearing loss in EED and EES syndrome, we measured the volume of the EED and EES, the diameter of the EED and EES, the area of the cochlear modiolus, and the signal intensity of the EES and compared our findings against degree of hearing loss. METHODS: Thin-section MR images of 33 ears in 17 patients with EED and EES syndrome were studied. All studies were obtained on a 1.5-T MR unit using a quadrature surface phased-array coil. Heavily T2-weighted 3D fast asymmetric spin-echo images were obtained with a voxel size of 0.3 x 0.3 x 0.8 mm without zero-fill interpolation. Two radiologists traced the areas of the EED and EES manually, and the volume was calculated. The area of the cochlear modiolus, diameter of the EED and EES, and signal intensity of the EES were also measured by drawing regions of interest manually. The signal intensity ratio of EES/CSF was calculated. These measured values were compared against audiographic data, and the degree of linear correlation was determined. RESULTS: The volume of the EED and EES, the area of the modiolus, the diameter of the EED and EES, and the signal intensity of the EES did not show significant correlation with degree of hearing loss. CONCLUSION: These findings suggest that there is a microscopic area of damage or fragility in the inner ear not visible even with thin-section heavily T2-weighted MR imaging.

Adolescent↗

PubMed1983

Ultrasonographic differentiation of the gestational sac of early intrauterine pregnancy from the pseudogestational sac of ectopic pregnancy.

A retrospective review of 128 consecutively scanned pregnant patients who had either early intrauterine pregnancies (IUPs) or ectopic pregnancies was performed to determine the accuracy of the finding of an intrauterine double decidual sac (DDS) in distinguishing between these two groups of patients. The presence of a DDS correlated with an IUP in 59 of 60 patients (98.3%). Of 68 patients who lacked a DDS, only four had normal IUPs; the remaining patients had either ectopic pregnancies or abnormal IUPs. Results of this study suggest that the finding of a DDS at ultrasonography is useful in making an early diagnosis of IUP, while its absence strongly suggests either an ectopic pregnancy or an abnormal IUP.

Decidua↗