1,366 research outputs found
Formation of the ovarian follicular antrum and follicular fluid
No full textThe formation of the follicular antrum and follicular fluid has received scant attention from researchers, yet both are important processes in follicular development. The central hypothesis on follicular fluid formation suggests that production by granulosa cells of hyaluronan and the chondroitin sulphate proteoglycan versican generates an osmotic gradient. This gradient draws in fluid derived from the thecal vasculature. Inter-alpha-trypsin inhibitor is also present in follicular fluid at least in species with large follicles, and inter-alpha-trypsin inhibitor and versican could additionally bind or cross-link with hyaluronan, resulting in the retention of these molecules within the follicular antrum. Barriers to the movement of fluid across the membrana granulosa are apparently minimal, as even relatively large serum proteins are present in follicular fluid. Despite the relative permeability of the follicular wall, aquaporins are present in granulosa cells and could be actively involved in the transport of water into the follicle. The formation of an antrum also requires movement of granulosa cells relative to each other to allow the fluid to accumulate. This presumably involves remodeling of cell-cell junctions and in species with small follicles may involve death of centrally located granulose cells. Remodeling of the stroma and thecal layers also accompanies growth and expansion of the antrum and presumably involves similar processes that accompany growth of other glands.Raymond J. Rodgers and Helen F. Irving-Rodger
Morphological classification of bovine ovarian follicles
No full textCopyright © 2010 Society for Reproduction and FertilityFollicle classification is an important aid to the understanding of follicular development and atresia. Some bovine primordial follicles have the classical primordial shape, but ellipsoidal shaped follicles with some cuboidal granulosa cells at the poles are far more common. Preantral follicles have one of two basal lamina phenotypes, either a single aligned layer or one with additional layers. In antral follicles 5 mm, only aligned/rounded phenotypes are present. Dominant and subordinate follicles can be identified by ultrasound and/or histological examination of pairs of ovaries. Atretic follicles 5 mm, only antral atresia is observed. The concentrations of follicular fluid steroid hormones can be used to classify atresia and distinguish some of the different types of atresia; however, this method is unlikely to identify follicles early in atresia, and hence misclassify them as healthy. Other biochemical and histological methods can be used, but since cell death is a part of normal homoeostatis, deciding when a follicle has entered atresia remains somewhat subjective.R. J. Rodgers and H. F. Irving-Rodger
The Will to Disempower? Nabokov and his Readers
No full textRodgers argues that aspects of Nietzsche’s philosophy—specifically “master-slave morality” and the “will to power”—can articulate the interplay between author and reader in Nabokov’s work. Informed by Bernard Reginster’s interpretation of the will to power as the “activity of overcoming resistance,” the chapter claims that the disempowering distinction between elevated author and subjugated reader in Nabokov’s fiction engenders a readerly resistance. Rodgers illustrates this distinction by drawing on Nabokov’s published university lectures, on the epigraph and foreword to his novel Invitation to a Beheading, and on his short story “The Vane Sisters.” “The Will to Disempower? Nabokov and His Readers” focuses on the risks of readerly resistance as well as its empowering implications for “Nietzschean readers,” those who are conscious of Nabokov’s textual practice
Extracellular matrix of the developing ovarian follicle
No full textThere are many different types of extracellular matrices in the different follicle compartments. These have different roles in follicle development and atresia, and they change in composition during these processes. This review focuses on basal lamina matrix in particular, and considers follicular fluid, the newly identified focimatrix, and thecal matrices. When follicles commence growing, the follicular basal lamina changes in its composition from containing all six alpha chains of type IV collagen to only alpha1 and alpha2. Perlecan and nidogen-1 and -2 subsequently become components of the follicular basal lamina, and there is an increase in the amount of laminin chains alpha1, beta2, and gamma1, in the bovine at least. Late in follicular development and on atresia some follicles contain laminin alpha2. On atresia the follicular basal lamina is not degraded, as occurs in ovulation, but can be breached by cells from the thecal layer when it is not aligned by granulosa cells. A novel type of basal lamina-like matrix, called focimatrix (abbreviated from focal intraepithelial matrix), develops between the cells of the membrana granulosa as aggregates of basal lamina material. It does not envelop cells and so cannot perform functions of basal lamina as currently understood. It is hypothesized that focimatrix assists or initiates depolarization of the membrana granulosa necessary for the transformation into luteal cells. The largest osmotically active molecules in follicular fluid are hyaluronan and chondroitin sulfate proteoglycans, including versican and inter-alpha trypsin inhibitor. It has been suggested that these might be responsible for the formation of follicular fluid by creating an osmotic gradient across the follicular wall. The formation, development, and then either ovulation or regression of follicles requires considerable tissue remodeling, cellular replication, and specialization. The expectation of researchers is that extracellular matrix will be intimately involved in many of these processes. Much research has focused in identifying the components of extracellular matrix and associated developmental changes. We review the components of extracellular matrix associated with follicular development, including the basal lamina, focimatrix, follicular fluid, and matrix of the thecal layers.Helen F. Irving-Rodgers, Raymond J. Rodger
Extracellular matrix in ovarian follicular development and disease
No full textThe original publication is available at www.springerlink.comThe ovarian follicle contains several different cell types and separate compartments and undergoes substantial development during its growth and maturation. Extracellular matrix (ECM) could be expected to play a major role in these processes. Most research on ECM in follicles has focused on the follicular basal lamina and its changing composition during folliculogenesis and on the specialised matrix formed at ovulation by the cumulus cells surrounding the oocyte and the zona pellucida. We review these aspects. Few naturally occurring gene mutations have identified unique roles for ECM molecules in follicular function. Presumably, any mutations leading to reduced fertility are eliminated quickly by natural selection and, when mutations are not eliminated, considerable redundancy occurs to ensure successful reproduction. In mice, in which the genome can be easily manipulated, the modification of matrix components associated with cumulus and oocytes has often resulted in partial infertility, suggesting redundancy. We provide an update of basal lamina components focusing on newer discoveries. In addition, we review matrix associated with the occyte and cumulus cells (excluding the zona pellucida) and other components of ECM. Where possible, we examine evidence for the role of the ECM in follicular development and diseases.Helen F. Irving-Rodgers and Raymond J. Rodger
Connecting
Get PDFHelen Walker. Connecting.
Steven DeGeorge —The Things They Bring to School .
Johanna Rodgers —Translating Authority
Jeremiah Conway —Emily\u27s Cav
The campaign for democratic socialism 1960-1964.
No full textPhDIn early 1960 it seemed likely that the official Labour
Party defence policy would be defeated by a unilateralist
resolution at the Scarborough Conference. In response to
this possibility the Campaign for Democratic Socialism,
or CDS, was established.
The CDS projected the image of a grass-roots movement
inspired by Gaitskell's "fight and fight again" speech.
But it was run by a Campaign Committee which included
leading members of the Party like Tony Crosland, Roy
Jenkins and Patrick Gordon Walker, as well as less well
known members like Bill Rodgers, Dick Taverne, Philip
Williams, Brian Walden, Denis Howell and David Marquand.
This highly talented group launched an elaborate and
successful lobbying, publicity and briefing operation
which was influential in overturning the unilateralist
vote at the Blackpool Conference of 1961. After Blackpool
the Campaign helped many of its leading members find
seats in the House of Commons while continuing to put the
"revisionist" case through its newspaper Campaign.
The importance of the CDS in the history of the Labour
Party is, primarily, as the first internal pressure group
organised by the right of the Party. It was also the
first internal Party group to use such sophisticated
lobbying techniques. Moreover, the subsequent careers of
the leading members of the Campaign influenced the
development of the Labour Party. The CDS was an important
formative political action for many of them. Finally many
of the CDS supporters set-up or joined the SDP when it
was launched
Extracellular matrix of the human cyclic corpus luteum
Get PDF© The Author 2006Extracellular matrix regulates many cellular processes likely to be important for development and regression of corpora lutea. Therefore, we identified the types and components of the extracellular matrix of the human corpus luteum at different stages of the menstrual cycle. Two different types of extracellular matrix were identified by electron microscopy; subendothelial basal laminas and an interstitial matrix located as aggregates at irregular intervals between the non-vascular cells. No basal laminas were associated with luteal cells. At all stages, collagen type IV 1 and laminins 5, ß2 and 1 were localized by immunohistochemistry to subendothelial basal laminas, and collagen type IV 1 and laminins 2, 5, ß1 and ß2 localized in the interstitial matrix. Laminin 4 and ß1 chains occurred in the subendothelial basal lamina from mid-luteal stage to regression; at earlier stages, a punctate pattern of staining was observed. Therefore, human luteal subendothelial basal laminas potentially contain laminin 11 during early luteal development and, additionally, laminins 8, 9 and 10 at the mid-luteal phase. Laminin 1 and 3 chains were not detected in corpora lutea. Versican localized to the connective tissue extremities of the corpus luteum. Thus, during the formation of the human corpus luteum, remodelling of extracellular matrix does not result in basal laminas as present in the adrenal cortex or ovarian follicle. Instead, novel aggregates of interstitial matrix of collagen and laminin are deposited within the luteal parenchyma, and it remains to be seen whether this matrix is important for maintaining the luteal cell phenotype.Helen F. Irving-Rodgers, Barbro E. Friden, Stephanie E. Morris, Helen D. Mason, Mats Brannstrom, Kiyotoshi Sekiguchi, Noriko Sanzen, Lydia M. Sorokin, Yoshikazu Sado, Yoshifumi Ninomiya, and Raymond J. Rodger
Expression of focimatrix correlates with expression of enzymes for estradiol and progesterone synthesis in ovarian follicles
No full textRaymond Joseph Rodgers and Helen Frances Irving-Rodger
The pitfalls of using a child support schedule based on outdated data
No full textA strong rationale for updating child support guidelines arises from changes over time in the measurement of expenditures on children, as well as changes in the empirical relationship between expenditures on children and the income of parents. Such changes affect the accuracy of the numerics upon which states’ child support guidelines are based. This study evaluates an alternative child support guideline that was proposed for Virginia and draws lessons for other states that similarly base their guidelines on older survey data. Regression results show that over time, the child expenditure and household income relationship has changed considerably. Furthermore, the largest increases in expenditures attributable to children have occurred for lower- and middle-income households.Peer reviewe
- …
