scholarly journals Composition and morphology of the follicular basal lamina during atresia of bovine antral follicles

Reproduction ◽  
2002 ◽  
pp. 97-106 ◽  
Author(s):  
HF Irving-Rodgers ◽  
ML Mussard ◽  
JE Kinder ◽  
RJ Rodgers
Keyword(s):  
Basal Lamina ◽  
Granulosa Cells ◽  
Cell Shape ◽  
Type Iv Collagen ◽  
Basal Cells ◽  
Follicle Growth ◽  
Electron Microscopic ◽  
Antral Follicles ◽  
Type Iv ◽  
Follicle Diameter

The fate of the follicular basal lamina during atresia was investigated using bovine follicles, in which different follicle phenotypes have been observed. These phenotypes include: healthy follicles with rounded basal granulosa cells with an aligned basal lamina or follicles with columnar basal granulosa cells with a basal lamina of many loops (loopy), and atretic follicles in which either the antral granulosa cells (antral atresia) or the basal cells (basal atresia) die first. Loopy lamina and basal atresia occur only in small antral follicles < 5 mm in diameter. Follicles were collected from cattle of unknown reproductive history and processed for immunohistochemistry and electron microscopy, and from animals in which follicle growth had been monitored by daily measurements of follicle diameter by ultrasonography. Electron microscopic observations of dominant follicles during the growth phase, plateau and regression showed that the basal lamina was still visible and intact upon atresia. These follicles had a conventional aligned basal lamina, which they retained, except for some degree of folding, as they progressed into antral atresia. In small follicles (2-5 mm in diameter), the basal cell shape (rounded or columnar) and appearance of the basal lamina (aligned or of many loops) did not appear to be related to the type of atresia. On atresia the follicular basal laminae retained immunoreactive laminin alpha1 and beta2, type IV collagen alpha1 and nidogen. Laminin alpha2, which may come from the theca, was present in the follicular basal lamina of only 22% of healthy follicles, but was expressed very commonly in 71% of the atretic follicles. Laminin alpha2 expression was found in both phenotypes of healthy follicles, antral and basal atretic follicles, and follicles with aligned or loopy basal laminae. It is concluded that the basal lamina is not degraded upon atresia, but does undergo a variety of other changes.

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 Morphological classification of bovine ovarian follicles

Reproduction ◽  
2010 ◽  
Vol 139 (2) ◽  
pp. 309-318 ◽  
Author(s):  
R J Rodgers ◽  
H F Irving-Rodgers
Keyword(s):  
Basal Lamina ◽  
Granulosa Cells ◽  
Follicular Development ◽  
Basal Cells ◽  
Morphological Classification ◽  
Primordial Follicles ◽  
Antral Follicles ◽  
Different Types ◽  
Biological Differences

Follicle 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 diameter, half of the healthy follicles have columnar shaped basal granulosa cells and additional layers of basal lamina, which appear as loops in cross section (‘loopy’). The remainder have aligned single-layered follicular basal laminas with rounded basal cells, and contain better quality oocytes than the loopy/columnar follicles. In sizes >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 are either basal atretic or antral atretic, named on the basis of the location in the membrana granulosa where cells die first. Basal atretic follicles have considerable biological differences to antral atretic follicles. In 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.

scholarly journals Implication of cortisol and 11β-hydroxysteroid dehydrogenase enzymes in the development of porcine (Sus scrofa domestica) ovarian follicles and cysts

Reproduction ◽  
2007 ◽  
Vol 133 (6) ◽  
pp. 1149-1158 ◽  
Author(s):  
Neera Sunak ◽  
Daphne F Green ◽  
Lalantha R Abeydeera ◽  
Lisa M Thurston ◽  
Anthony E Michael
Keyword(s):  
Granulosa Cells ◽  
Hydroxysteroid Dehydrogenase ◽  
Ovarian Follicles ◽  
Cyst Fluid ◽  
Ovarian Cysts ◽  
Follicle Growth ◽  
Antral Follicles ◽  
Cortisol Metabolism ◽  
Porcine Granulosa Cells ◽  
Follicle Diameter

This study investigated cortisol inactivation by 11β-hydroxysteroid dehydrogenase (11β HSD) enzymes in porcine granulosa cells from antral follicles at different developmental stages and in ovarian cysts. In granulosa cells, cortisol oxidation increased threefold with antral follicle diameter (P < 0.001). This trend was paralleled by a threefold increase in NADP+-dependent 11β-dehydrogenase activity in granulosa cell homogenates with follicle diameter. Intact granulosa cells from ovarian cysts exhibited significantly lower enzyme activities than cells from large antral follicles. Neither intact cells norcell homogenates displayed net 11-ketosteroid reductase activities. Since porcine follicular fluid (FF) from large antral follicles and ovarian cysts contains hydrophobic inhibitors of glucocorticoid metabolism by type 1 11β HSD, this studyalso investigated whether levels of 11β HSD inhibitors changed during follicle growth and could affect cortisol metabolism in granulosa cells. The extent of inhibition of 11β HSD1 activity in rat kidney homogenates decreased progressively from 50 ± 8% inhibition by FF from small antral follicles (P < 0.001) to 23 ± 6% by large antral FF (P < 0.05). Cyst fluid inhibited 11β HSD1 activity by 59 ± 4% (P < 0.001). Likewise, net cortisol oxidation in granulosa cells was significantly decreased by large antral FF (35–48% inhibition, P < 0.05) and cyst fluid (45–75% inhibition, P < 0.01). We conclude that inactivation of cortisol by 11β HSD enzymes in porcine granulosa cells increases with follicle development but is significantly decreased in ovarian cysts. Moreover, changes in ovarian cortisol metabolism are accompanied by corresponding changes in the levels of paracrine inhibitors of 11β HSD1 within growing ovarian follicles and cysts, implicating cortisol in follicle growth and cyst development.

An analysis of cell shape and the neuroepithelial basal lamina during optic vesicle formation in the mouse embryo

Development ◽  
1987 ◽  
Vol 100 (2) ◽  
pp. 185-200 ◽  
Author(s):  
K.K. Svoboda ◽  
K.S. O'Shea
Keyword(s):  
Electron Microscopy ◽  
Basal Lamina ◽  
Cell Shape ◽  
Type Iv Collagen ◽  
Heparan Sulphate ◽  
Intercellular Junctions ◽  
Ultrastructural Analysis ◽  
Vesicle Formation ◽  
Optic Vesicle ◽  
Type Iv

The optic vesicle develops as an evagination of the cephalic neural folds. We have examined the early development of the optic vesicle in Swiss Webster mice using correlated transmission electron microscopy (TEM), scanning electron microscopy (SEM), light microscopic (LM) measurements of cell shape changes, immunohistochemical localization of basal lamina (BL) components (type IV collagen, laminin and heparan sulphate proteoglycan (HSPG)) and ultrastructural analysis of the BL. Like the neuroepithelium in other regions, the low columnar cells of the neural plate in the future optic vesicle region become high columnar, then wedge shaped following constriction of the cell apices to form the C-shaped vesicle. In this region, the cells elongate 2 times their initial height before the neural tube closes, then shorten 20% as the vesicle is completed. Cell apices decrease in width by about one half during vesicle formation. Deposition of BL components was initially even, with type IV collagen and laminin reduced in deposition in regions of outpouching. At later stages the linear, even distribution of all four components was re-established. Ultrastructural analysis confirmed the BL discontinuity and re-establishment and correlated the observed cell shaping alterations with apparent increases in the number of microtubules (during elongation) and microfilaments (during apical constriction). The number of apical intercellular junctions also appeared to increase in number during optic vesicle formation, possibly providing stability and coordination to the evagination process.

scholarly journals Atresia revisited: two basic patterns of atresia of bovine antral follicles

Reproduction ◽  
2001 ◽  
pp. 761-775 ◽  
Author(s):  
HF Irving-Rodgers ◽  
IL van Wezel ◽  
ML Mussard ◽  
JE Kinder ◽  
RJ Rodgers
Keyword(s):  
Basal Lamina ◽  
Granulosa Cells ◽  
Immunohistochemical Study ◽  
Steroid Hormone ◽  
Basal Layer ◽  
Follicle Development ◽  
Basal Cells ◽  
Apoptotic Bodies ◽  
Antral Follicles ◽  
Follicular Fluids

Our observations of bovine follicles indicated that the original histological classifications of atresia were inaccurate. A detailed histological, ultrastructural and immunohistochemical study of antral follicles from bovine ovaries collected from an abattoir and from animals whose large follicles had been monitored by ultrasonography was conducted to investigate this further. Nidogen and CD68 were immunolocalized to observe the follicular basal lamina and macrophages, respectively. In randomly collected ovaries, approximately one quarter of all antral follicles were undergoing antral atresia, as designated in this study. Antral atresia was characterized by early destruction of the layers of the membrana granulosa closest to the antrum, whereas the most basal cells remained intact. Numerous pyknotic nuclei were observed in the most antral layers and in the antrum close to the membrana granulosa. This is the classic description of atretic follicles and was observed at all sizes of follicle development and almost universally in large follicles (> 5 mm in diameter), including dominant follicles. Basal atretic follicles, as designated in this study, were almost as prevalent as the antral atretic follicles, and were characterized by initial destruction of the most basal layer of granulosa cells, whereas the cells in the most antral layers remained associated with each other and were predominantly healthy. Pyknotic nuclei and the nuclei of dying basal cells budded into apoptotic bodies were observed rarely. The basal lamina of basal atretic follicles was often breached by macrophages, which were phagocytosing dying basal granulosa cells. The theca was characterized by an increased deposition of collagen, and the cells were orientated randomly, rather than lying parallel to the membrana granulosa as in healthy follicles. Basal atresia occurred in small (< 5 mm in diameter) follicles only. Importantly, these basal atretic follicles were originally identified incorrectly in the literature. Thus, on the basis of the results of this study and another on the expression of steroidogenic enzymes in atretic follicles, it is suggested that the standard biochemical methods for measuring steroid hormone concentrations in follicular fluids to assess atresia should be re-evaluated.

The use of 1nm silver enhanced gold probes for the detection of skin antigens

1990 ◽  
Vol 48 (3) ◽  
pp. 902-903
Author(s):  
J.P Cassella ◽  
H. Shimizu ◽  
A. Ishida-Yamamoto ◽  
R.A.J. Eady
Keyword(s):  
Type Iv Collagen ◽  
Freeze Substitution ◽  
Collagen Type Iv ◽  
Electron Microscopic ◽  
Normal Human Skin ◽  
Type Iv ◽  
Type Vii Collagen ◽  
Keratin Filaments ◽  
Normal Human ◽  
Phosphate Buffered Saline

1nm colloidal gold with silver enhancement has been used in conjunction with a low-temperature post-embedding (post-E) technique for the demonstration of skin antigens at both the light microscopic (LM) and electron microscopic (EM) levels.Keratin filaments and basement membrane zone (BMZ) associated antigens in normal human skin (NHS) were immunolabelled using antibodies against keratin 14, 10, and 1, the carboxy-terminus and collagenous portion of type VII collagen, type IV collagen and bullous pemphigoid antigen (BP-Ag).Fresh samples of NHS were cryoprotected in 15% glycerol, cryofixed in propane at -190°C, subjected to freeze substitution in methanol at -80°C and embedded in Lowicryl K11M at -60°C. Polymerisation of the resin was initiated under UVR at - 60°C for 48 hours and continued at room temperature for a further 48 hours. Semith in sections were air dried onto slides coated with 3-aminopropyltriethoxysilane. The following immunolabelling protocol was adopted: Primary antibody was applied for 2 hours at 37°C or overnight at 4°C. Following washing in Dulbecco’s phosphate buffered saline (PBSA) a biotinylated secondary antibody was applied for 2 hours at 37°C. The sections were further washed in PBSA and 1nm gold avidin was applied. Sections were finally washed in PBSA and silver enhanced.

scholarly journals Monoclonal antibodies against chicken type IV and V collagens: electron microscopic mapping of the epitopes after rotary shadowing.

1984 ◽  
Vol 98 (5) ◽  
pp. 1637-1644 ◽  
Author(s):  
R Mayne ◽  
H Wiedemann ◽  
M H Irwin ◽  
R D Sanderson ◽  
J M Fitch ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Monoclonal Antibodies ◽  
Cleavage Site ◽  
Type Iv Collagen ◽  
Collagen Molecule ◽  
Electron Microscopic ◽  
Type V Collagen ◽  
Type Iv ◽  
Type V ◽  
Rotary Shadowing

The location of the epitopes for monoclonal antibodies against chicken type IV and type V collagens were directly determined in the electron microscope after rotary shadowing of antibody/collagen mixtures. Three monoclonal antibodies against type IV collagen were examined, each one of which was previously demonstrated to be specific for only one of the three pepsin-resistant fragments of the molecule. The three native fragments were designated (F1)2F2, F3, and 7S, and the antibodies that specifically recognize each fragment were called, respectively, IA8 , IIB12 , and ID2 . By electron microscopy, monoclonal antibody IA8 recognized an epitope located in the center of fragment (F1)2F2 and in tetramers of type IV collagen at a distance of 288 nm from the 7S domain, the region of overlap of four type IV molecules. Monoclonal antibody IIB12 , in contrast, recognized an epitope located only 73 nm from the 7S domain. This result therefore provides direct visual evidence that the F3 fragment is located closest to the 7S domain and the order of the fragments must be 7S-F3-(F1)2F2. The epitope for antibody ID2 was located in the overlap region of the 7S domain, and often several antibody molecules were observed to binding to a single 7S domain. The high frequency with which antibody molecules were observed to bind to fragments of type IV collagen suggests that there is a single population of type IV molecules of chain organization [alpha 1(IV)]2 alpha 2(IV), and that four identical molecules must form a tetramer that is joined in an antiparallel manner at the 7S domain. The monoclonal antibodies against type V collagen, called AB12 and DH2 , were both found to recognize epitopes close to one another, the epitopes being located 45-48 nm from one end of the type V collagen molecule. The significance of this result still remains uncertain, but suggests that this site is probably highly immunoreactive. It may also be related to the specific cleavage site of type V collagen by selected metalloproteinases and by alpha-thrombin. This cleavage site is also known to be located close to one end of the type V molecule.

scholarly journals Shift in collagen type as an early response to induction of the metanephric mesenchyme.

1981 ◽  
Vol 89 (2) ◽  
pp. 276-283 ◽  
Author(s):  
P Ekblom ◽  
E Lehtonen ◽  
L Saxén ◽  
R Timpl
Keyword(s):  
Basal Lamina ◽  
Type Iv Collagen ◽  
Early Response ◽  
Type I ◽  
Metanephric Mesenchyme ◽  
Type Iv ◽  
Interstitial Collagens ◽  
Membrane Components

Conversion of the nephrogenic mesenchyme into epithelial tubules requires an inductive stimulus from the ureter bud. Here we show with immunofluorescence techniques that the undifferentiated mesenchyme before induction expresses uniformly type I and type III collagens. Induction both in vivo and in vitro leads to a loss of these proteins and to the appearance of basement membrane components including type IV collagen. This change correlates both spatially and temporally with the determination of the mesenchyme and precedes and morphological events. During morphogenesis, type IV collagen concentrates at the borders of the developing tubular structures where, by electron microscopy, a thin, often discontinuous basal lamina was seen to cover the first pretubular cell aggregates. Subsequently, the differentiating tubules were surrounded by a well-developed basal lamina. No loss of the interstitial collagens was seen in the metanephric mesenchyme when brought into contact with noninducing tissues or when cultured alone. Similar observations were made with nonnephrogenic mesenchyme (salivary, lung) when exposed to various heterotypic tissues known to induce tubules in the nephrogenic mesenchyme. The sequential shift in the composition of the extracellular matrix from an interstitial, mesenchymal type to a differentiated, epithelial type is so far the first detectable response of the nephrogenic mesenchyme to the tubule-inducing signal.

The relationship between emerging neural crest cells and basement membranes in the trunk of the mouse embryo: a TEM and immunocytochemical study

Development ◽  
1986 ◽  
Vol 98 (1) ◽  
pp. 251-268
Author(s):  
J. Sternberg ◽  
S. J. Kimber
Keyword(s):  
Neural Crest ◽  
Neural Tube ◽  
Cell Shape ◽  
Type Iv Collagen ◽  
Neural Crest Cell ◽  
Basement Membranes ◽  
Type Iv ◽  
Transmission Electron ◽  
The Relationship ◽  
Crest Cell

The earliest stage of neural crest cell (NCC) migration is characterized by an epitheliomesenchymal transformation, as the cells leave the neural tube. There is evidence that in a number of cell systems this transformation is accompanied by alteration or depletion of associated basement membranes. This study examines the ultrastructural relationship between mouse NCCs and adjacent basement membranes during the earliest stages of migration from the neural tube. Basement membranes were identified by transmission electron microscopy (TEM) and immunofluorescence using antibodies to type-IV collagen. The ultrastructural features of NCCs and their relationship with surrounding tissues were also examined using TEM. In the dorsal region of the neural tube, from which NCCs originate, the basement membrane was depleted or absent, and with the immunofluorescence technique it was shown that this pattern was reflected in a deficit of type-IV collagen. TEM observations indicated that ultrastructurally NCCs differ from their neuroepithelial neighbours only in overall cell shape and their relationship to other cells and the extracellular matrix.

Comparative analysis of basal lamina type IV collagen α chains, matrix metalloproteinases-2 and -9 expressions in oral dysplasia and invasive carcinoma

2013 ◽  
Vol 115 (2) ◽  
pp. 113-119 ◽  
Author(s):  
Ryo Tamamura ◽  
Hitoshi Nagatsuka ◽  
Chong Huat Siar ◽  
Naoki Katase ◽  
Ichiro Naito ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Matrix Metalloproteinases ◽  
Basal Lamina ◽  
Type Iv Collagen ◽  
Invasive Carcinoma ◽  
Oral Dysplasia ◽  
Type Iv
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