bluuebunny/crossref_metadata_2025_split huggingface dataset:
Variation in articular cartilage in rabbits between weeks six and eight
Authors: Oreja Maria Teresa Castaño , Rodriguez Maximino Quintáns , Abelleira Antonio Crespo , García Manuel Avelino Giráldez , García Miguel Angel Saavedra , Barreiro Francisco Javier Jorge 
Published: February 2005

AbstractBackground: Previous studies of variation in cartilage characteristics with age have involved comparison of young and adult individuals, but no data on short‐term age‐related change are available. Such data are important for studies of the response of cartilage to experimental stimuli in young rabbits, to distinguish the response to the stimuli from accompanying age‐related changes.Methods: We used light microscopy to study the thickness, cell density, and degree of histological definition of articular cartilage on the femoral trochlea of 6‐, 7‐, and 8‐week‐old rabbits.Results: Thickness and cell density both decline significantly with age. The decline in cell density is more marked in surface layers of cartilage and is accompanied by an increase in the safranin O‐staining affinity of the extracellular matrix and an extension of this affinity towards the surface.Conclusions: Our results indicate that the synthesis of matrix components becomes more important relative to proliferative activity. The traditionally defined histological layers (zones I, II, III, and IV) are not clearly distinguishable in rabbits of this age. In 6‐ and 7‐week old animals only a “surface” (I/II) and a “deep” layer (III) can be distinguished. By 8 weeks, zones I and II are well defined but the mineralization front (marking the boundary between zones III and IV) is still absent. © 1995 Wiley‐Liss, Inc.
Integrin and phosphotyrosine expression in normal and migrating newt keratinocytes
Authors: Donaldson Donald J. , Mahan James T. , Yang Hui , Yamada Kenneth M. 
Published: February 2005

AbstractBackground: Cells interact with the extracellular matrix through a family of cell surface receptors known as integrias. Ligand specificity of a given integrin is determined in part by the type of α and the type of β subunit comprising it. Accumulating evidence suggests that integrinligand binding in some systems influences cell behavior through tyrosine phosphorylation of intracellular proteins.Methods: In this study, we utilized immunohistochemistry to examine the expression of β1 and β4 integrin subunits as well as tyrosine phosphorylation in normal keratinocytes and in keratinocytes migrating to form a wound epithelium. An adhesion assay was used to determine if freshly isolated keratinocytes could interact with fibronectin and collagen. Polyacrylamide gel electrophoresis followed by immunoblotting was employed to compare β1 integrins in migrating and nonmigrating keratinocytes.Results: In normal epidermis, β1 and β4 localized primarily to basal cells, where both subunits were generally distributed over all parts of the cell periphery. Except for a modest presence in suprabasal cells and a minimal presence adjacent to the epidermal basement membrane, phosphotyrosine (ptyr) had a similar distribution. In migrating keratinocytes, β1, β4, and ptyr localized most heavily at the interface between the forming wound epithelium and the wound bed. Adhesion assays using keratinocytes from normal epidermis revealed a population of cells that could specifically adhere and spread on fibronectin and type I collagen. Immunoblots of β1 subunits from normal and migrating keratinocytes showed no increase in amount of β1, nor did the apparent size of β1 change in migrating compared to normal cells.Conclusions: The heavy accumulation of β1 and β4 at the wound bed interface in migrating cells suggests that these subunits may be involved in attachments of migrating cells to extracellular matrix proteins in the wound. The accumulation of ptyr in the same region further suggests that integrin‐ligand interaction in keratinocytes modulates cell behavior through phosphorylated proteins. The fact that freshly isolated newt keratinocytes could adhere and spread on fibronectin or collagen shows that these cells are constitutively activated. This view is supported by the absence of any evidence that the β1 in migrating keratinocytes is larger and therefore more mature than β1 in normal keratinocytes. By comparison, β1 integrins on human keratinocytes are not constitutively activated (Takashima and Grinnell, 1985; Toda et al., 1987; Guo et al., 1990, 1991), a difference that may explain why epidermal wound healing is faster in newts than in humans. © 1995 Wiley‐Liss, Inc.
Changes in the arrangement of actin filaments in myoid cells and sertoli cells of rat testes during postnatal development and after experimental cryptorchidism
Authors: Maekawa Mamiko , Kazama Hirohito , Kamimura Kyoko , Nagano Toshio 
Published: February 2005

AbstractBackground: Abundant actin filaments are present in myoid cells and Sertoli cells in the testis. In the adult rat, the filaments form a lattice arrangement within the myoid cell, and show a hexagonal pattern in the basal junctional regions of Sertoli cells.Methods: Isolated seminiferous tubules and frozen sections were prepared from juvenile to adult Wistar rat testes, stained with FITC‐conjugated phalloidin, and observed by confocal microscopy. Unilateral cryptorchidism was induced in adult rats, and seven days later, their testes were also examined.Results: In the myoid cell, parallel actin filaments running circularly around the seminiferous tubules were observed at 15 and 20 days of age. Then, at 30 days, actin filaments arranged longitudinally along the tubular long axis appeared in addition to the circular bundles. A lattice arrangement of actin‐filament bundles in myoid cells became obvious at 40 days, when elongated spermatids are found in the tubule. Actin filaments in the basal junctional regions of Sertoli cells did not acquire the hexagonal pattern seen in the adult testis until 30 days of age. In the cryptorchid testes, the arrangement of actin filaments in the both cells showed a remarkable change compared to the control testis; the filaments became thinner and disrupted.Conclusions: A lattice arrangement of the actin filaments in the myoid cell appear at around 30 days, before the completion of spermatogenesis. A hexagonal pattern of the filaments in the junctional regions of Sertoli cells has already developed at this age. Cryptorchidism affects the actin filaments of the both cells. © 1995 Wiley‐Liss, Inc.
Actin, α‐actinin, and spectrin with specific associations with the postacrosomal and acrosomal domains of bovine spermatozoa
Authors: Yagi Ahmed , Paranko Jorma 
Published: February 2005

AbstractBackground: Characteristic membrane changes in spermatozoa culminating in acrosome reaction and sperm‐egg fusion, and suspected involvement of actin‐containing cytoskeleton in membrane changes in general, prompted us to investigate subcellular distribution of actin and actin‐binding proteins in bovine spermatozoa subjected to various extractions which sequentially denude the sperm investments.Methods: Spermatozoa were treated with either 1% SDS, 0.1% Triton X‐100, 0.1% Hyamine, or 1 M MgCl2 or were sonicated. Immunostaining of actin, α‐actinin, spectrin, and acrosin as well as electron microscopic analysis of extracted spermatozoa were carried out.Results: Extractions caused evagination of the acrosomal lamina which retained focal contacts with the inner acrosomal membrane. Extractions further revealed lateral prongs at the anterior border of the postacrosomal sheath. Labeling for α‐actinin and spectrin was localized in the acrosinpositive acrosomal lamina, neck, and principal piece, the latter containing also relatively extraction‐resistant oligomeric or polymerized actin. In the postacrosomal area, actin was accumulated in the extraction‐resistant posterior ring structure and anteriorly at the sites apparently related to the lateral prongs. Notably, spectrin reactivity was enhanced by MgCl2 in head, neck, and principal piece, and sonication abolished cytoskeletal immunoreactivity in the head.Conclusions: Destabilization of membranes with selected extractions induces changes in the acrosomal lamina mimicking acrosomal vesicle formation. The lateral prongs and posterior ring structure, respectively, may serve as anterior and posterior anchors for the extraction‐resistant post‐acrosomal sheath. The lateral prongs may also be a merger zone for actin, α‐actinin, and spectrin with important implication on sperm function. The latter two proteins may be involved in acrosomal vesicle formation. It is apparent that extractions have a significant effect on the detectability of sperm cytoskeletal elements. © 1995 Wiley‐Liss, Inc.
Isolation of intramitochondrial helical filaments appearing in outer compartment of mitochondria
Authors: Sasaki Hiroyuki , Kurioka Susumu , Fukata Hiroyuki , Ohoki Takao , Arai Hisako , Suzuki Teruo 
Published: February 2005

AbstractBackground: Packets of helical filaments have been observed in the outer compartment of occasional mitochondria in many cell types in a variety of animals. The compositon and funcation of these intramitochondrial helical filaments (IMHF) are unknown.Methods: IMHF wre induced in a hepatic mitochondria by administration of ethanol in the drinking water of rats. Hepatic mitochondria were isolated and ruptured by osmotic shock, relasing their IMHF. To purify these structures, the IMHF‐containing supernatant was further fractionated by ammonium sulfate precipitation, a 50–60% solution of this reagent being the most effective in this regard. Isolated IMHF were examined by electron microcopy and were analyzed by SDS‐PAGE.Result Isolated IMHF closely resembled their in situ counterparts: they had a right‐handed helical structure with a 16 nm pitch. SDS‐PAGE analysis revealed that they contained three polypeptides with weigh tmolecular of 135, 98, and 53 kD, respectively.Conculusions: These observations will stand as a aseline for comparisons with IMHF that occur naturally or that are induced in other cell types by other kinds of experimental manipulation. © 1995 Wiley‐Liss, Inc.
Effects of lateral pterygoid muscle hyperactivity on differentiation of mandibular condyles in rats
Authors: Takahashi Ichiro , Mizoguchi Itaru , Nakamura Masanori , Kagayama Manabu , Mitani Hideo 
Published: February 2005

AbstractBackground: The effects of biomechanical stress on the growth and development of the mandibular condyle have been studied by many investigators. However, the role of the lateral pterygoid muscle in this development is not clear.Methods: Hyperfunction of the lateral pterygoid muscles of male 3‐weekold Sprague‐Dawley rats was induced by electrical stimulation, and the responses of the mandibular condyles were compared to control tissues by a double‐fluorescent staining technique using polyclonal antibodies against type I and type II collagen. Electrical stimulation consisted of repeated application (5 seconds on/5 seconds off) of a Hz current for up to 7 days.Results: In the first 2 days, cartilaginous tissues rich in type II collagen disappeared in the anterior and posterior areas, which were loaded by tensional force due to direct and indirect attachment of the lateral pterygoid muscles. Tissues in these areas were replaced by intramembranous bone that was reactive for type I collagen at 7 days. By the end of the experiment, the trabecula of the condyle was remodled more perpendicularly, thus resisting the compressive force due to hyperfunction of the lateral pterygoid muscles.Conclusions: These results suggest that the activity of the lateral pterygoid muscle might play a significant role in the differentiation of progenitor cells and in the maturation and calcification of chondrocytes in mandibular condyles. © 1995 Wiley‐Liss, Inc.
Glycoconjugate expression in the chick embryonic chorioallantoic membrane: Comparisons of the chorionic ectoderm and allantoic endoderm
Authors: Henry Charmaine B. S. , Kleinstein Eric , Shum Wesley , DeFouw David O. 
Published: February 2005

AbstractBackground: The chorioallantoic membrne (CAM) of the chick embryo expands during embryogenesis to meet the increased oxygen demands during growth and differentiation. Temporal and spatial glycosylation patterns of CAM ectodermal and endodermal proteins likely contribute to differentiation of the functional attributes of the CAM.Methods: Using lectins for light and electron microscopic observations, we studied the patterns of glycoconjugate expression on the ectoderm and endoderm of the chorioallantoic membrane (CAM) of the chick at days 4.5, 5.0, 6.0, and 10 of morphogenesis. For light microscopy, samples of unfixed CAM were incubated with the following FITC lectins: Con A, DBA, GSA‐I, GSA‐II, PNA, SBA, UEA‐I, and WGA.Results: All lectins, except GSA‐I and ‐II, gave positive results. The positive lectins, labeled with HRP, served to ultrastructurally localize PNA, SBA, and WGA, but not DBA binding to the luminal surface of the endoderm. UEA‐I and Con A bound similarly except on day 10 when UEA‐I no longer bound. On the ectodermal surface, only WGA bound at all times studied. PNA and SBA binding were present from days 5.0 to 6.0 but absent at days 4.5 and 10. DBA binding occurred through day 5.0 but was absent thereafter. UEA‐I bound to the ectoderm at days 4.5, 5.0, and 10 but not days 5.5 and 6.0 Con A bound only on days 5.0 and 10.Conclusion: That the ultrastructurally similar ectoderm and endoderm of the CAM display functional differences conforms to the hypothesis that differential expression of glycoconjugate microdoains likely contributes to such functional specialization. © 1995 Wiley‐Liss, Inc.
Anatomy and histology of the cardiac conal valves of the adult dogfish (Scyliorhinus canicula)
Authors: Sans‐Coma Valentín , Gallego Alejandro , Muñoz‐Chápuli Ramón , De Andrés A. Victoria , Durán Ana C. , Fernández Borja 
Published: February 2005

AbstractBackground: Knowledge of the structural arrangement of the cardiac conal valves in Elasmobranchs is scarce. The present study was designed to assess the anatomical and histological features of the conal valves of the dogfish as a starting point for further investigation of the mechanical properties of these valves.Methods: The sample examined consisted of 31 adult dogfishes. The study was carried out using scanning electron microscopy and histological techniques for light microscopy.Results: In the dogfish, the conus arteriosus contains two transverse rows of valves. The anterior row lies at the level of the conus‐ventral aorta junction and is composed of three valves of similar size. The posterior row is near the conus‐ventricular junction and consists of four valves, one of them very reduced in size. Each valve shows two components, namely, the leaflet and its supporting structure, the sinus. In the anterior valves, the length of the leaflets between their lateral attachments to the sinus wall is remarkably longer than the straight‐line distance between the points of attachment. This allows each leaflet to close against the other two leaflets of the same row, even when the conus is relaxed. The leaflets of the posterior valves are anchored to the conus wall by means of tendinous cords and cannot practically bridge the lumen of the relaxed conus. Each leaflet has a stout central body in which the connective tissue is stratified in three layers: outer fibrosa, spongiosa, and inner fibrosa. The lateral parts of the leaflet mainly consist of a single fibrous layer that bifurcates into the outer and inner fibrosa layers of the central body. The sinus walls of the posterior valves are entirely made up of conal tissue, whereas those of the anterior valves incorporate an aortic component.Conclusions: The present findings suggest that the inner fibrosa and the fibrous lateral portions of the leaflets mainly bear the stress of pressure generated by blood backflow. The stretching of the leaflets in the radial direction may basically depend on the spongiosa, whereas the outer fibrosa determines the radial stiffness of the leaflets. © 1995 Wiley‐Liss, Inc.
Parasympathetic preganglionic neurons in the spinal cord involved in uterine innervation are cholinergic and nitric oxide‐containing
Authors: Papka Raymond E. , McCurdy James R. , Williams Sonya J. , Mayer Bernd , Marson Lesley , Platt Kenneth B. 
Published: February 2005

AbstractBackground: The purpose of this study was to elucidate parasympathetic preganglionic neurons in the spinal cord that project axons in pathways to the uterus and to reveal their neurotransmitter phenotype.Methods: “Uterine‐related” neurons were identified by using a combination of retrograde axonal tracers: (1) Fluorogold injected into the ganglia of termination of preganglionic fibers, and (2) a transganglionic axonal tracer (pseudorabies virus) injected into the uterus. Immunohistochemistry was used to reveal virus‐labeled neurons and their neurotransmitter marker.Results: Double‐labeled (Fluorogold + pseudorabies virus) “uterine” preganglionic neurons were identified in the sacral parasympathetic nucleus of the rat lumbosacral spinal cord. Subpopulations of neurons in the sacral parasympathetic nucleus were shown to be immunoreactive for choline acetyltransferase or nitric oxide synthase. Double‐staining immunohistochemistry (for pseudorabies virus + neurotransmitter enzyme) revealed that some of the uterine‐related preganglionic neurons were cholinergic and some nitric oxide synthase‐containing.Conclusions: These results demonstrate a subpopulation of pregauglionic parasympathetic neurons in the sacral parasympathetic nucleus that are involved in uterine innervation. In addition, both acetylcholine and nitric oxide could be used to modify activity in the postganglionic neurons, which directly innervate the uterus. © 1995 Wiley‐Liss, Inc.
Ultrastructural and histochemical studies of the epiphyseal plate in normal chicks
Authors: Takechi Masato , Itakura Chitoshi 
Published: February 2005

AbstractBackground: Chondrocytes in the epiphyseal plate undergo a series of well‐defined stages, each stage containing a morphologically homogeneous cell population. However, biochemical studies show that there are some functionally heterogeneous cell types in the calcifying zone of the chick epiphyseal plate.Methods: We studied the sequence of chondrocytic maturation in the normal chick epiphyseal plate ultrastructurally and histochemically. Chondrocytes in the calcifying zone were of three distinct types, the appearance of each cell type being closely related to the stage of matrix calcification.Results: Clear cells were observed in the upper calcifying region, stellate cells appeared in the middle calcifying region, and hypertrophic clear cells appeared in the lower calcifying region. Rough endoplasmic reticulum (RER) and lysosome‐rich cells were found, these being limited to the outermost layers of the calcifying zone and containing ACPase‐positive products. Osteoclasts were attached to the matrix near the RER and lysosomerich cells in the poorly calcified regions.Conclusion: We hypothesized that each cell type played a different role in the initiation, progression, and maintenance of cartilage calcification. RER and lysosome‐rich cells may be responsible for the resorption of uncalcified cartilage matrix, this resulting in induction of the osteoclastic resorption of the calcified matrix. In addition, the fate of the chondrocytes was twofold: hypertrophic clear cells died, while the RER and lysosme‐rich cells survived, suggesting that these cells were transformed into osteogenic cells. © 1995 Wiley‐Liss, Inc.
Ultrastructural identification of the splenic follicular dendritic cells in the chicken
Authors: Gallego Margarita , del Cacho Emilio , Zapata Agustin , Bascuas Jose Antonio 
Published: February 2005

AbstractBackground: There is a need to identify the follicular dendritic cells (FDC) of the chicken spleen at the ultrastructural level during a secondary immune response.Methods: The cells were identified after intravenous priming BSA and boosting with biotinylated BSA conjugated to colloidal gold particles. Monoclonal antibodies raised specifically either to chicken IgG or IgM were used to characterize these immune complex‐trapping cells.Results: The FDC had an irregular morphology which varied through time, supporting the existence of two types of FDC in the chicken spleen, one showing filiform cell processes, the other provided with beaded dendrites. When the filiform dendrites were observed, the FDC bound the antigen on their surfaces. These dendrites showed an intrincate convoluted configuration, forming tightly wrapped networks near the cell body. The networks had the same features as those described in mammals as antigen retaining reticulum (ARR). In chickens, the ARR, which represents sites of antigen localization on FDC, reached maximum development on day 5 after the second injection of BSA and had disappeared by day 8. At this time FDC had beaded dendrites.Conclusions: Antigen is retained on FDC in the chicken spleen for long periods of time. © 1995 Wiley‐Liss, Inc.
Appearance and distribution of laminin a chain isoforms and integrin α2, α3, α6, β1, and β4 subunits in the developing human small intestinal mucosa
Authors: Perreault Nathalie , Vachon Pierre H. , Beaulieu Jean‐François 
Published: February 2005

AbstractBackground: Laminin, a major component of basement membranes, is well known in its classical heterotrimeric form (B1‐A‐B2) to regulate diverse biological functions, including cell polarization and differentiation. However, the role of merosin, a laminin‐like molecule in which an M chain is substituted for its homologous A chain, remains largely unknown.Methods: In the present study, we analyzed by indirect immunofluorescence the expression and distribution of these four laminin chains as well as the integrins α2β1, α3β1,α6β1, and α6β4, four potential recptors, at the epithelial‐mesenchymal interface of the developing human small intestine, with a panel of specific monoclonal antibodies.Results: Beginning at 7 weeks of gestation and throughout mucosal organogenesis, the B1 and B2 chains were uniformly detected at the epithelial basement membrane. The A chain also was detected beginning at 7 weeks, and its distribution at the basement membrane remained uniform throughout villus (9+ weeks) and crypt (16+ weeks) formation. In contrast, M chain expression was not observed until 16 weeks; between 16 and 20 weeks, it was exclusively associated with the base of epithelial cells that comprised the forming crypts. Integrins α6β1 and α6β4, as determined by their subunit immunolocalization, appeared to be expressed by all enterocytes from 7 to 20 weeks. In contrast, the expression of the α2β1 and α3β1 integrins was found time‐ and site‐restricted. The α2 subunit was predominantly detected in the epithelial cells of the intervillous area and its derivative, the crypt, whereas the α3 subunit was strongly expressed by all epithelial cells except those located at the bottom of 19–20‐week‐old crypts.Conclusions: Taken together, these observations demonstrate that both compositional changes in the basement membrane and differential expression of receptors occur during human intestinal organogenesis, suggesting that epithelial cell‐matrix interactions play a role during development. © 1995 Wiley‐Liss, Inc.