scholarly journals Mathematical modelling of oxygen transport-limited follicle growth

Reproduction ◽  
2007 ◽  
Vol 133 (6) ◽  
pp. 1095-1106 ◽  
Author(s):  
G P Redding ◽  
J E Bronlund ◽  
A L Hart
Keyword(s):  
Mathematical Modelling ◽  
Oxygen Transport ◽  
Size Range ◽  
Ovarian Follicle ◽  
Antral Follicle ◽  
Follicle Growth ◽  
Preantral Follicles ◽  
Formation Stage ◽  
Ultimate Fate ◽  
Further Development

Mathematical modelling was used to investigate oxygen transport in the developing ovarian follicle. In contrast to previous findings, the results show that oxygen can reach the oocyte in large preantral follicles. This is largely due to the inclusion of fluid voidage in the model and improved estimates of oxygen diffusion coefficients through the granulosa. The results also demonstrate that preantral follicles will eventually reach a size beyond which further growth will result in the follicle becoming increasingly anoxic. The predicted size range at which this occurs is consistent with the size range at which antrum formation is observed in many mammals. This suggests that the antrum formation stage of follicular growth may be pivotal to the further development and ultimate fate of the follicle, and that antrum formation itself may represent a mechanism by which the follicle can overcome oxygen limitations. This was supported through extension of the model to the antral follicle, which showed that antrum formation can provide a way in which the follicle can continue to grow and yet avoid becoming hypoxic. The results of the model were consistent with observed follicle development.

scholarly journals C-Type Natriuretic Peptide Stimulates Ovarian Follicle Development

2012 ◽  
Vol 26 (7) ◽  
pp. 1158-1166 ◽  
Author(s):  
Yorino Sato ◽  
Yuan Cheng ◽  
Kazuhiro Kawamura ◽  
Seido Takae ◽  
Aaron J.W. Hsueh
Keyword(s):  
Natriuretic Peptide ◽  
Granulosa Cells ◽  
Ovulation Induction ◽  
Ovarian Follicle ◽  
Antral Follicle ◽  
In Vivo Studies ◽  
Follicle Growth ◽  
Secondary Stage

Abstract C-type natriuretic peptide (CNP) encoded by the NPPC (Natriuretic Peptide Precursor C) gene expressed in ovarian granulosa cells inhibits oocyte maturation by activating the natriuretic peptide receptor (NPR)B (NPRB) in cumulus cells. RT-PCR analyses indicated increased NPPC and NPRB expression during ovarian development and follicle growth, associated with increases in ovarian CNP peptides in mice. In cultured somatic cells from infantile ovaries and granulosa cells from prepubertal animals, treatment with CNP stimulated cGMP production. Also, treatment of cultured preantral follicles with CNP stimulated follicle growth whereas treatment of cultured ovarian explants from infantile mice with CNP, similar to FSH, increased ovarian weight gain that was associated with the development of primary and early secondary follicles to the late secondary stage. Of interest, treatment with FSH increased levels of NPPC, but not NPRB, transcripts in ovarian explants. In vivo studies further indicated that daily injections of infantile mice with CNP for 4 d promoted ovarian growth, allowing successful ovulation induction by gonadotropins. In prepubertal mice, CNP treatment alone also promoted early antral follicle growth to the preovulatory stage, leading to efficient ovulation induction by LH/human chorionic gonadotropin. Mature oocytes retrieved after CNP treatment could be fertilized in vitro and developed into blastocysts, allowing the delivery of viable offspring. Thus, CNP secreted by growing follicles is capable of stimulating preantral and antral follicle growth. In place of FSH, CNP treatment could provide an alternative therapy for female infertility.

Ultrastructure of the basal lamina of bovine ovarian follicles and its relationship to the membrana granulosa

Reproduction ◽  
2000 ◽  
pp. 221-228 ◽  
Author(s):  
HF Irving-Rodgers ◽  
RJ Rodgers
Keyword(s):  
Basal Lamina ◽  
Granulosa Cells ◽  
Light And Electron Microscopy ◽  
Single Layer ◽  
Antral Follicle ◽  
Basal Cells ◽  
Preantral Follicles ◽  
Antral Follicles ◽  
Cellular Processes ◽  
Innermost Layer

Different morphological phenotypes of follicular basal lamina and of membrana granulosa have been observed. Ten preantral follicles (< 0. 1 mm), and 17 healthy and six atretic antral follicles (0.5-12 mm in diameter) were processed for light and electron microscopy to investigate the relationship the between follicular basal lamina and membrana granulosa. Within each antral follicle, the shape of the basal cells of the membrana granulosa was uniform, and either rounded or columnar. There were equal proportions of follicles </= 4 mm in diameter with columnar basal cells and with rounded basal cells. Larger follicles had only rounded basal cells. Conventional basal laminae of a single layer adjacent to the basal granulosa cells were observed in healthy follicles at the preantral and antral stages. However, at the preantral stage, the conventional types of basal lamina were enlarged or even partially laminated. A second type of basal lamina, described as 'loopy', occurred in about half the preantral follicles and in half the antral follicles </= 4 mm diameter. 'Loopy' basal laminae were not observed in larger follicles. 'Loopy' basal laminae were composed of basal laminae aligning the basal surface of basal granulosa cells, but with additional layers or loops often branching from the innermost layer. Each loop was usually < 1 microm long and had vesicles (20-30 nm) attached to the inner aspect. Basal cellular processes were also common, and vesicles could be seen budding off from these processes. In antral follicles, conventional basal laminae occurred in follicles with rounded basal granulosa cells. Other follicles with columnar cells, and atretic follicles, had the 'loopy' basal lamina phenotype. Thus, follicles have different basal laminae that relate to the morphology of the membrana granulosa.

scholarly journals Involvement of hyaluronan synthesis in ovarian follicle growth in rats

Reproduction ◽  
2014 ◽  
Vol 147 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Noriyuki Takahashi ◽  
Wataru Tarumi ◽  
Bunpei Ishizuka
Keyword(s):  
Ovarian Follicle ◽  
Primary Site ◽  
Corpora Lutea ◽  
Follicular Atresia ◽  
Follicle Growth ◽  
Adult Rats ◽  
Antral Follicles ◽  
Cell Layers ◽  
Ha Synthase

Most of the previous studies on ovarian hyaluronan (HA) have focused on mature antral follicles or corpora lutea, but scarcely on small preantral follicles. Moreover, the origin of follicular HA is unknown. To clarify the localization of HA and its synthases in small growing follicles, involvement of HA in follicle growth, and gonadotropin regulation of HA synthase (Has) gene expression, in this study, perinatal, immature, and adult ovaries of Wistar-Imamichi rats were examined histologically and biochemically and byin vitrofollicle culture. HA was detected in the extracellular matrix of granulosa and theca cell layers of primary follicles and more advanced follicles. Ovarian HA accumulation ontogenetically started in the sex cords of perinatal rats, and its primary site shifted to the intrafollicular region of primary follicles within 5 days of birth. TheHas1–3mRNAs were expressed in the ovaries of perinatal, prepubertal, and adult rats, and the expression levels ofHas1andHas2genes were modulated during the estrous cycle in adult rats and following administration of exogenous gonadotropins in immature acyclic rats. TheHas1andHas2mRNAs were predominantly localized in the theca and granulosa cell layers of growing follicles respectively. Treatments with chemicals known to reduce ovarian HA synthesis induced follicular atresia. More directly, the addition ofStreptomyceshyaluronidase, which specifically degrades HA, induced the arrest of follicle growth in anin vitroculture system. These results indicate that gonadotropin-regulated HA synthesis is involved in normal follicle growth.

Inhibition of Ovarian Follicle Growth by a Chemical Antiestrogen

1982 ◽  
Vol 16 (4) ◽  
pp. 230-236 ◽  
Author(s):  
R. Nakano ◽  
T. Nakayama ◽  
M. Iwao
Keyword(s):  
Ovarian Follicle ◽  
Follicle Growth

X-Ray Binary Stars and Ovarian Follicle Growth: Math Models in Astrophysics and Physiology

2010 ◽  
Author(s):  
Gordon E. Sarty ◽  
Curtis Saxton ◽  
Kinwah Wu ◽  
Roger Pierson ◽  
N. Mebarki ◽  
...  
Keyword(s):  
Binary Stars ◽  
Ovarian Follicle ◽  
Follicle Growth ◽  
X Ray

scholarly journals Oriented basement membrane fibrils provide a memory for F-actin planar polarization via the Dystrophin-Dystroglycan complex during tissue elongation

2019 ◽  
Author(s):  
Fabiana Cerqueira Campos ◽  
Cynthia Dennis ◽  
Hervé Alégot ◽  
Cornelia Fritsch ◽  
Adam Isabella ◽  
...  
Keyword(s):  
Basement Membrane ◽  
Ovarian Follicle ◽  
Follicle Cell ◽  
Autonomous Control ◽  
Stress Fibers ◽  
Follicle Growth ◽  
Growth Promoting ◽  
Fibers Orientation ◽  
Open Question ◽  
The Relationship

SummaryHow extracellular matrix participates to tissue morphogenesis is still an open question. In the Drosophila ovarian follicle, it has been proposed that after Fat2-dependent planar polarization of the follicle cell basal domain, oriented basement membrane (BM) fibrils and F-actin stress fibers constrain follicle growth, promoting its axial elongation. However, the relationship between BM fibrils and stress fibers and their respective impact on elongation are unclear. We found that Dystroglycan (Dg) and Dystrophin (Dys) are involved in BM fibril deposition. Moreover, they orient stress fibers, by acting locally and in parallel to Fat2. Nonetheless, Dg-Dys complex-mediated cell autonomous control of F-actin fibers orientation relies on the previous BM fibril deposition, indicating two distinct but interdependent functions. Thus, the Dg-Dys complex works as a critical organizer of the epithelial basal domain, regulating both F-actin and BM. Furthermore, BM fibrils act as a persistent cue for the orientation of stress fibers that are the main effector of elongation.

Interpolation of Missing Part of Human Follicle Border on Ultrasonic B-Mode Image by Iterative Revision

2000 ◽  
Vol 22 (2) ◽  
pp. 108-122
Author(s):  
Y. Yamakoshi ◽  
M. Takemoto ◽  
N. Shinozuka
Keyword(s):  
Ovarian Follicle ◽  
A Priori ◽  
Three Dimensional ◽  
Closed Curve ◽  
Smoothness Condition ◽  
A Priori Information ◽  
Follicle Growth ◽  
Cross Sectional ◽  
Geometrical Characteristics ◽  
Priori Information

In clinical infertility treatments, assessment of ovarian follicle growth by ultrasonography is important. In order to measure the geometrical characteristics of the human follicle, such as the area of the cross-sectional image and the volume inside the follicle, a method based on manual tracing of the follicle contour from the ultrasonic B mode image is widely used. However, the observable ultrasonic B mode images are sometimes imperfect and some parts of the follicle border are missing due to the existence of the acoustic shadow. In this paper, a method that interpolates the missing part of the follicle border from the known part is proposed. This method uses a priori information of the follicle, which is usually known in actual cases: (1) the follicle's surface is so smooth that its border is assumed to be a smooth closed curve; and (2) the position of the follicle's center is roughly predicted in advance in the ultrasonic B-mode image. In the proposed method, the missing part of the human follicle border is interpolated from the known part by applying an iterative revision so as to satisfy the smoothness condition of the follicle. This method is also applied to three-dimensional image reconstruction of the human follicle.

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