scholarly journals The role of the Wolffian ducts in the formation of the sinus vagina: an organ culture study

Development ◽  
1983 ◽  
Vol 73 (1) ◽  
pp. 275-295
Author(s):  
Gabriele Bok ◽  
Ulrich Drews
Keyword(s):  
Organ Culture ◽  
Mouse Embryos ◽  
The Other ◽  
Urogenital Sinus ◽  
Female Development ◽  
Culture Study ◽  
Male Development ◽  
Stage Of Development ◽  
Sinus Formation

In mammals formation of a sinus vagina is inhibited in the male by endogenous testosterone from the embryonic testes. To answer the question which morphogenetic events during formation of thevagina are influenced by testosterone, we explanted genital tracts of mouse embryos in the indifferent stage of development in organ culture. Half of the explants were treated with testosterone and therefore developed in male direction. The other half was kept without testosterone and developed constitutively in female direction. Since the antiMüller factor was not present, in both types of cultures the Müllerian ducts were preserved. During female development the Müllerian ducts fused with the dorsolaterally apposed caudal segments of the Wolffian ducts. Thus the caudal segments of the Wolffian ducts were incorporated in the vaginal plate, while cranially the Wolffian ducts degenerated as expected. During male development fusion between Müllerian and Wolffian ducts did not occur. Under the influence of testosterone the respective caudal segments of the Wolffian ducts were surrounded by dense mesenchyme and further male differentiation took place. We conclude that the ‘sinus protrusions’ or ‘sinovaginal bulbs’ observed during development of the vagina, are in fact the caudal segments of the Wolffian ducts. They serve as a link between Müllerian ducts and urogenital sinus. Formation of a sinus vagina is prevented by testosterone simply by induction of male development in this area.

scholarly journals The role of NDI on the failure analysis of an aircraft propeller hub

2018 ◽  
Vol 188 ◽  
pp. 04021
Author(s):  
Iordanis Spyroglou ◽  
Angelos Koutsomichalis ◽  
Panos Stavropoulos ◽  
Nikolaos Roussis
Keyword(s):  
High Stress ◽  
Sem Analysis ◽  
The Other ◽  
Propeller Blade ◽  
High Stress Concentration ◽  
The Third ◽  
Stage Of Development ◽  
Corrosion Pits ◽  
Non Destructive

This paper analyses the causes of an incident in an aircraft propeller hub. The aluminum alloy propeller blade hub was detached from the plane bearing one of its two blades with the other one being jettisoned away. Stereoscopic examination of the fractured hub revealed that it was initially cracked by fatigue, with the crack initiating on the root of the third and fourth spirals and propagating form the inner to the outer. SEM analysis showed that the crack epicentres were created very close or/and on the spiral roots and were attributed to microcracks from corrosion pits and high stress concentration. Non Destructive Inspection was both used on the other side of the hub and the remaining three hubs of the plane and confirmed the presence of cracks similar to those which caused the fatigue failure of the fractured hub but at earliest stage of development.

The Party in Uniform: Toward a Theory of Civil-Military Relations in Communist Political Systems

1982 ◽  
Vol 76 (4) ◽  
pp. 778-789 ◽  
Author(s):  
Amos Perlmutter ◽  
William M. LeoGrande
Keyword(s):  
Division Of Labor ◽  
The Other ◽  
Political Systems ◽  
Civil Military Relations ◽  
Stage Of Development ◽  
Political Resource ◽  
Military Relations ◽  
The Military ◽  
Over Time

This article is an effort to establish a comparative theoretical framework for the study of civil-military relations in communist political systems. Although the literature on civil-military relations in polyarchic and praetorian polities is theoretically as well as empirically rich, theories of civil-military relations in the field of comparative communism are still at the preliminary stage of development. It is argued that civil-military relations, like all the fundamental dynamics of communist political systems, derive from the structural relationship between a hegemonic Leninist party and the other institutions of the polity. Although the party directs and supervises all other institutions, its political supremacy is necessarily limited by the division of labor among various institutions. The relative autonomy of the military and its relations with the party vary from one country to another and can be described as coalitional, symbiotic, or fused. These relations are dynamic, changing over time in each country in response to contextual circumstances. The role of the military in politics is complex and variegated: on ideological issues, there is usually little conflict between party and army; on issues of “normal politics,” the military acts as a functionally specific elite engaged in bargaining to defend its perceived institutional interests; and in crisis politics, the military is a political resource that various party factions seek to enlist against their opponents.

The role of 5a-reduction in steroid hormone physiology

2001 ◽  
Vol 13 (8) ◽  
pp. 673 ◽  
Author(s):  
Jean D. Wilson
Keyword(s):  
Essential Role ◽  
Steroid Hormone ◽  
Urogenital Sinus ◽  
Receptor Complex ◽  
Hormone Action ◽  
Steroid Molecule ◽  
Male Development ◽  
Broad Specificity

A role for 5α-reduction in androgen physiology was first established with the recognition that dihydrotestosterone, the 5α-reduced metabolite of testosterone, is formed in many androgen target tissues, binds to the androgen receptor with greater affinity than testosterone, and plays an essential role in virilization of the urogenital sinus and urogenital tubercle during male development. Two 5α-reductases perform this reaction, and both isoenzymes utilize NADPH as cofactor and have broad specificity for steroids containing a Δ4, 3-keto configuration. 5α-Reduction, which is essentially irreversible, flattens the steroid molecule because of altered relation of the A and B rings, and stabilizes the hormone–receptor complex. Studies involving in vitro reporter gene assays and intact mice in which both isoenzymes are disrupted, indicate that the fundamental effect of dihydrotestosterone formation is to amplify hormonal signals that can be mediated by testosterone at higher concentrations. 5α-Reduction also plays a role in the action of other steroid hormones, including the plant growth hormone, brassinolide, the boar pheromones, androstanol and androstenol, progesterone (in some species), and, possibly, aldosterone and cortisol. The fact that the reaction is important in plants and animals implies a fundamental role in steroid hormone action.

scholarly journals The TRANSFORMER Genes of the Fern Ceratopteris Simultaneously Promote Meristem and Archegonia Development and Repress Antheridia Development in the Developing Gametophyte

Genetics ◽  
1997 ◽  
Vol 147 (4) ◽  
pp. 1885-1897 ◽  
Author(s):  
Jo Ann Banks
Keyword(s):  
Sex Determination ◽  
Sex Expression ◽  
The Other ◽  
Female Development ◽  
Epistatic Interactions ◽  
Male Development ◽  
Sporophyte Development

Abstract The sex of the haploid gametophyte of the fern Ceratopteris is determined by the presence or absence of the pheromone antheridiogen, which, when present, promotes male development and represses female development of the gametophyte. Several genes involved in sex determination in Ceratopteris have been identified by mutation. In this study, the epistatic interactions among new and previously described sex-determining mutants have been characterized. These results show that sex expression is regulated by two sets of genes defined by the FEM1 and TRA loci. Each promotes the expression of either male or female traits and simultaneously represses the expression of the other. A model describing how antheridiogen regulates the expression of these genes and the sex of the gametophyte is described. The observation that some gametophytic sexdetermining mutants have phenotypic effects on the spore phyte plant indicates that sex determination in the Ceratopteris gametophyte is regulated by a mechanism that also regulates sporophyte development.

scholarly journals Triploid plover female provides support for a role of the W chromosome in avian sex determination

2012 ◽  
Vol 8 (5) ◽  
pp. 787-789 ◽  
Author(s):  
Clemens Küpper ◽  
Jakob Augustin ◽  
Scott Edwards ◽  
Tamás Székely ◽  
András Kosztolányi ◽  
...  
Keyword(s):  
Sex Determination ◽  
Sex Chromosome ◽  
W Chromosome ◽  
Female Development ◽  
Linked Gene ◽  
Charadrius Alexandrinus ◽  
Male Development ◽  
Polymorphic Microsatellite ◽  
Kentish Plover

Two models, Z Dosage and Dominant W , have been proposed to explain sex determination in birds, in which males are characterized by the presence of two Z chromosomes, and females are hemizygous with a Z and a W chromosome. According to the Z Dosage model, high dosage of a Z-linked gene triggers male development, whereas the Dominant W model postulates that a still unknown W-linked gene triggers female development. Using 33 polymorphic microsatellite markers, we describe a female triploid Kentish plover Charadrius alexandrinus identified by characteristic triallelic genotypes at 14 autosomal markers that produced viable diploid offspring. Chromatogram analysis showed that the sex chromosome composition of this female was ZZW. Together with two previously described ZZW female birds, our results suggest a prominent role for a female determining gene on the W chromosome. These results imply that avian sex determination is more dynamic and complex than currently envisioned.

PROSTATIC INDUCTION: INTERACTION OF EPITHELIUM AND MESENCHYME FROM NORMAL WILD-TYPE MICE AND ANDROGEN-INSENSITIVE MICE WITH TESTICULAR FEMINIZATION

1980 ◽  
Vol 85 (3) ◽  
pp. 423-NP ◽  
Author(s):  
ILSE LASNITZKI ◽  
TAKEO MIZUNO
Keyword(s):  
Organ Culture ◽  
Androgen Receptors ◽  
Prostate Gland ◽  
Mutant Mice ◽  
Urogenital Sinus ◽  
Testicular Feminization ◽  
Wild Type ◽  
Normal Epithelium ◽  
Normal Wild Type

The prostate gland develops from the urogenital sinus as epithelial buds projecting into the surrounding mesenchyme. The role of the mesenchyme in this process was determined using sinuses from normal and androgen-insensitive Tfm mice which are deficient in androgen receptors. Epithelium and mesenchyme from both types of sinus were separated and recombined and the recombinants grown in organ culture in the presence of testosterone. Recombinants consisting of normal epithelium and normal mesenchyme developed epithelial buds projecting into the surrounding mesenchyme but no buds were formed in recombinants of epithelium and mesenchyme from mutant mice. In recombinants of epithelium from mutant mice with normal mesenchyme the epithelium developed prostatic buds and the number was similar to that found if normal epithelium was associated with normal mesenchyme. In contrast, normal epithelium combined with mesenchyme from mutant mice failed to form prostatic buds. The results suggested that the mesenchyme determines the development of prostatic buds and that the lack of inductive capacity of the mesenchyme from mutant mice may be due to a deficiency of mesenchymal androgen receptors.

scholarly journals Chondrogenic Priming at Reduced Cell Density Enhances Cartilage Adhesion of Equine Allogeneic MSCs - a Loading Sensitive Phenomenon in an Organ Culture Study with 180 Explants

2015 ◽  
Vol 37 (2) ◽  
pp. 651-665 ◽  
Author(s):  
Jan H. Spaas ◽  
Sarah Y. Broeckx ◽  
Koen Chiers ◽  
Stephen J. Ferguson ◽  
Marco Casarosa ◽  
...  
Keyword(s):  
Organ Culture ◽  
Cell Density ◽  
Clinical Results ◽  
The Other ◽  
Cartilage Explants ◽  
Culture Study ◽  
Allogeneic Mscs ◽  
Other Hand ◽  
Cell Densities ◽  
Pulsed Electromagnetic

Background: Clinical results of regenerative treatments for osteoarthritis are becoming increasingly significant. However, several questions remain unanswered concerning mesenchymal stem cell (MSC) adhesion and incorporation into cartilage. Methods: To this end, peripheral blood (PB) MSCs were chondrogenically induced and/or stimulated with pulsed electromagnetic fields (PEMFs) for a brief period of time just sufficient to prime differentiation. In an organ culture study, PKH26 labelled MSCs were added at two different cell densities (0.5 x106 vs 1.0 x106). In total, 180 explants of six horses (30 per horse) were divided into five groups: no lesion (i), lesion alone (ii), lesion with naïve MSCs (iii), lesion with chondrogenically-induced MSCs (iv) and lesion with chondrogenically-induced and PEMF-stimulated MSCs (v). Half of the explants were mechanically loaded and compared with the unloaded equivalents. Within each circumstance, six explants were histologically evaluated at different time points (day 1, 5 and 14). Results: COMP expression was selectively increased by chondrogenic induction (p = 0.0488). PEMF stimulation (1mT for 10 minutes) further augmented COL II expression over induced values (p = 0.0405). On the other hand, MSC markers remained constant over time after induction, indicating a largely predifferentiated state. In the unloaded group, MSCs adhered to the surface in 92.6% of the explants and penetrated into 40.7% of the lesions. On the other hand, physiological loading significantly reduced surface adherence (1.9%) and lesion filling (3.7%) in all the different conditions (p < 0.0001). Remarkably, homogenous cell distribution was characteristic for chondrogenic induced MSCs (+/- PEMFs), whereas clump formation occurred in 39% of uninduced MSC treated cartilage explants. Finally, unloaded explants seeded with a moderately low density of MSCs exhibited greater lesion filling (p = 0.0022) and surface adherence (p = 0.0161) than explants seeded with higher densities of MSCs. In all cases, the overall amount of lesion filling decreased from day 5 to 14 (p = 0.0156). Conclusion: The present study demonstrates that primed chondrogenic induction of MSCs at a lower cell density without loading results in significantly enhanced and homogenous MSC adhesion and incorporation into equine cartilage.

Localization of Intracisternal a Particle Antigens in Neoplastic Cells and Preimplantation Mouse Embryos

1980 ◽  
Vol 38 ◽  
pp. 696-697
Author(s):  
Thomas T.F. Huang ◽  
Patricia G. Calarco
Keyword(s):  
Endoplasmic Reticulum ◽  
Normal Development ◽  
Mouse Embryos ◽  
Neoplastic Cells ◽  
Large Numbers ◽  
Preimplantation Mouse Embryos ◽  
Preimplantation Mouse ◽  
Intracisternal A Particle ◽  
Normal Feature

The stage specific appearance of a retravirus, termed the Intracisternal A particle (IAP) is a normal feature of early preimplantation development. To date, all feral and laboratory strains of Mus musculus and even Asian species such as Mus cervicolor and Mus pahari express the particles during the 2-8 cell stages. IAP form by budding into the endoplasmic reticulum and appear singly or as groups of donut-shaped particles within the cisternae (fig. 1). IAP are also produced in large numbers in several neoplastic cells such as certain plasmacytomas and rhabdomyosarcomas. The role of IAP, either in normal development or in neoplastic behavior, is unknown.

Plasma Levels of Protein S, Protein C, and Factor X: Effects of Sex, Hormonal State and Age

1995 ◽  
Vol 74 (05) ◽  
pp. 1271-1275 ◽  
Author(s):  
C M A Henkens ◽  
V J J Bom ◽  
W van der Schaaf ◽  
P M Pelsma ◽  
C Th Smit Sibinga ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Postmenopausal Women ◽  
Protein C ◽  
Blood Donors ◽  
Premenopausal Women ◽  
Protein S ◽  
The Other ◽  
Factor X ◽  
Normal Ranges

SummaryWe measured total and free protein S (PS), protein C (PC) and factor X (FX) in 393 healthy blood donors to assess differences in relation to sex, hormonal state and age. All measured proteins were lower in women as compared to men, as were levels in premenopausal women as compared to postmenopausal women. Multiple regression analysis showed that both age and subgroup (men, pre- and postmenopausal women) were of significance for the levels of total and free PS and PC, the subgroup effect being caused by the differences between the premenopausal women and the other groups. This indicates a role of sex-hormones, most likely estrogens, in the regulation of levels of pro- and anticoagulant factors under physiologic conditions. These differences should be taken into account in daily clinical practice and may necessitate different normal ranges for men, pre- and postmenopausal women.

On the role of the dispute between "non-possessors" and "Josephites" in the culture of Moscow's prediction

1998 ◽  
pp. 61-62
Author(s):  
N. S. Jurtueva
Keyword(s):  
The Other ◽  
Moral Transformation ◽  
15Th Century ◽  
The Future ◽  
Secular Power

In the XIV century. centripetal tendencies began to appear in the Moscow principality. Inside the Russian church, several areas were distinguished. Part of the clergy supported the specificobar form. The other understood the need for transformations in society. As a result, this led to a split in the Russian church in the 15th century for "non-possessors" and "Josephites". The former linked the fate of the future with the ideology of hesychasm and its moral transformation, while the latter sought support in alliance with a strong secular power.

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