bluuebunny/crossref_metadata_2025_split huggingface dataset:
A contribution with review to the description of mineralization of bone and other calcified tissues in vivo
Authors: Christoffersen J. , Landis W. J. 
Published: February 2005

AbstractThis manuscript considers certain aspects of mineral deposition in bone and other vertebrate calcifying tissues in order to examine physical, chemical, and biological factors important in the mineralization process. The paper in a discussion format principally presents new data and the formulation of concepts based on such data as well as a summary of background material as necessary review. Mineralization is found to occur at spatially independent sites throughout the organic extracellular tissue matrices. Matrix vesicles and collagen fibrils each may serve as independent nucleation centers for mineral with vesicle mineralization being local and collagen mineralization dominating the tissues as a whole. Collagen fibril organization is suggested to be such that hole zones are aligned in three dimensions, creating extensive channels for mineral accommodation. Nucleation occurs initially in hole zones and crystal growth leads to the development of plate‐like mineral particles whose orientation, disposition, and sizes within fibrils are detailed. Effects of diffusion, crystallinity, and critical nucleation and growth events are described with respect to their influence on mineral deposition in bulk and local regions of tissue matrices.
Occurrence of bioactive and immunoreactive inhibin (13 KD) in human epididymis
Authors: Phadke Achyut M. , Garde Seema V. , Sheth Anil R. 
Published: February 2005

AbstractUsing specific polyclonal antibodies generated against a 13 KD human testicular inhibin, immunocytochemical localization of inhibin was carried out in different regions of human epididymis. The concentrations of inhibin were greater in caput and corpus regions as compared to the caudal region. The epididymal inhibin was found to be bioactive, since it suppressed specifically the FSH levels of rat pituitaries in vitro. Spermiophage/macrophage cells exhibited strong staining for inhibin which were suggestive of a possible role of inhibin in modulation of immune function. In view of the known activities of inhibin in cellular growth, differentiation, and steroidogenesis, epididymal inhibin could have a role in acquisition of sperm fertilizing capabilities.
Evidence for the presence of actin‐associated intercellular adhesion junctions between interstitial cells of Leydig in the ground squirrel testis
Authors: Pfeiffer D. C. , Vogl A. W. 
Published: February 2005

AbstractInterstitial cells of Leydig characteristically occur in clusters around blood vessels. Often these clusters remain intact when interstitial tissues are mechanically separated from other components of the testis. The presence of strong intercellular attachments is most likely one of the factors responsible for Ground Squirrel Testis Vancouver, British Columbia, Canada V6T 1Z3, maintaining the integrity of Leydig cell clusters. In many tissues, actin associated adhesion junctions commonly provide intercellular attachment. To determine if actin associated adhesion junctions are present between Leydig cells, we have used 1) immunofluorescence to probe for two components that characterize these junctions in other tissues and 2) electron microscopy to examine areas of intercellular contact for evidence of microfilament related adhesion junctions.Isolated clusters of unsectioned cells, which had been fixed and detergent extracted, were probed with the F‐actin specific stains rhodamine phalloidin and NBD‐phallacidin and with an affinity purified primary antibody raised against human platelet vinculin. In regions of intercellular contact, fluorescence staining with the actin probes was intense and appeared as a solid linear band. Similar regions also stained with the vinculin probe. In double label experiments, actin and vinculin probes were co‐distributed at sites of intercellular contact.Zones of intercellular contact, apparently similar to those detected with fluorescence microscopy, were observed a t the ultrastructural level. At these sites, subsurface filaments, interpreted by us as actin, formed a dense carpet adjacent to the lasma membrane on each side of the junction. These filaments appeared to be organized into networks rather than discrete bundles.Our observations that 1) probes for actin and vinculin codistribute at certain sites of intercellular contact and 2) a layer of microfilaments is associated with the plasma membrane in electron micrographs of these contact regions support the conclusion that Leydig cells, at least in the ground squirrel, may possess actin associated adhesion junctions similar to those described between cells of numerous other types.
Motor neurons of the laryngeal nerves
Authors: Patrickson J. W. , Smith T. E. , Zhou S.‐S. 
Published: February 2005

AbstractThe present study was undertaken to determine the relationship between the motor neurons of the superior and recurrent laryngeal nerves within the nucleus ambiguus. The retrograde transport of horseradish peroxidase was utilized to identify the motor neurons subsequent to its application to the proximal transected end of the superior and recurrent laryngeal nerves. Labeled superior laryngeal motor neurons were distributed ventrolaterally in the rostral portion of the nucleus. The recurrent laryngeal motor neurons were distributed throughout the nucleus with two distinct populations: a rostral group and a caudal group. The rostral group overlaps the motor neurons of the superior laryngeal nerve. The caudal group occupies that portion of the nucleus that is classically described for the recurrent laryngeal nerve. Additional superior laryngeal nerve labeled perikarya were found in the dorsal motor nucleus of the vagus. This study defines the rostral distribution of the recurrent laryngeal nerve motor neurons and suggests that this rostral group is a component of the neuroanatomical substrate that is involved in the co‐activation of the laryngeal abductors controlling the laryngeal aperture.
In vivo morphometry and functional morphology of brown adipose tissue by magnetic resonance imaging
Authors: Sbarbati Andrea , Baldassarri Angela Maria , Zancanaro Carlo , Boicelli Andrea , Osculati Francesco 
Published: February 2005

AbstractBrown adipose tissue (BAT) is the main effector of nonshivering thermogenesis and diet‐induced thermogenesis in mammals. Assessment of the magnitude and perturbations of BAT deposits in the intact, living body would be of much relevance for quantitative studies of BAT functions, but such studies have been impossible to date. In this paper it is shown that magnetic resonance imaging (MRI) morphometry can provide the means for accurate, repeated determinations of the volume of BAT deposits in a living animal; moreover, tissue modifications due to acclimation at different ambient temperatures are revealed in vivo by MRI, which correlates with histology and ultrastructure. Furthermore, MRI differentiates areas of BAT responsive to acute adrenergic stimulation, thereby giving information on the thermogenetically active tissue in the intact animal. Therefore, MRI represents a reliable tool for correlative morphological and functional studies of BAT in the living animal.
A quantitative study of satellite cells and myonuclei in stretched avian slow tonic muscle
Authors: Winchester P. K. , Gonyea W. J. 
Published: February 2005

AbstractSatellite cell frequency was assessed in control and stretched anterior latissimus dorsi (ALD) muscles of adult quail. A weight equal to 10% of body mass was attached to one wing for time intervals ranging from 1–30 days. The contralateral ALD served as the intra‐animal control. Satellite cell frequency, expressed as a percentage of total myofiber nuclei within the basal lamina, was determined in eight control and stretched ALD muscles, that had been weighted for 5, 7, or 10 days. Satellite cell frequency was determined in 584 control and 473 stretched fibers and was not different in the control or stretched ALD muscles (15.6 ± 2.3%, 16.7 ± 6.1%, respectively). The number of myofiber nuclei (myonuclei and satellite cell nuclei) was examined in whole fiber segments from control and stretched ALD muscles of 27 adult quail. Nuclear frequency was determined in 500 control and 1,200 stretched fiber segments. Fiber volume was calculated from fiber length and diameter measurements. Nuclear number normalized to 10,000 μm3 fiber volume was correlated to fiber cross‐sectional area (P < 0.0001). Fibers with cross‐sectional areas less than 500 μm2 had a greater nuclear to fiber volume ratio compared to fibers with areas greater than 500 μm2. The nuclear‐to‐cytoplasmic ratio was not constant in smaller fibers. Nuclear density decreased as fiber cross‐sectional area increased up to 500 μm2. Fibers with cross‐sectional areas greater than 500 μm2 demonstrated a constant nuclear‐to‐cytoplasmic ratio. The results demonstrate that absolute nuclear number increased to maintain a constant nuclear‐to‐cytoplasmic ratio in the stretched hypertrophied fibers. Daughter cells originating from activated satellite cells may have contributed to the myonuclear population to maintain a constant nuclear‐to‐cytoplasmic ratio in the hypertrophied fibers of the adult quail.
High incidence of multiple‐bag fiber muscle spindles in the articularis humeri muscle of the horse
Authors: Lalatta‐Costerbosa G. , Barazzoni A. M. , Clavenzani P. , Petrosino G. , Callegari E. , Bortolami R. 
Published: February 2005

AbstractThe articularis humeri (AH) muscle of the horse is a small muscle composed of histochemically identified type I and IIA extrafusal fibers and a large number of muscle spindles. A total of 150 complete spindles with both spindle poles available were examined in serial transverse sections. On the basis of myosin ATPase‐staining reactions after alkaline and acid preincubations, four types of intrafusal fibers, namely, bag1, bag2, “mixed” bag, and chain fibers, were identified.A high proportion of the spindle population (62.6%) consisted of multiple‐bag spindles containing three or more (up to six) bag fibers. Also one‐bag‐fiber spindles were observed. The one‐bag‐fiber spindles containing a bag2 fiber could be traced into tandem linkages. “Mixed” bag intrafusal fibers, differing in their ATPase staining profile at the two poles, were found in spindles containing also at least one bag1 and one bag2 fiber. An unusually long extracapsular tract (up to 5,500 μm) of the bag intrafusal fibers was observed.
Ordered distribution of membrane‐associated dense plaques in intact quail gizzard smooth muscle cells revealed by freeze‐fracture following treatment with cholesterol probes
Authors: Davis Elaine C. , Shivers Richard R. 
Published: February 2005

AbstractThe surface distribution of membrane‐associated dense plaques in intact quail gizzard smooth muscle cells was investigated by freeze‐fracture. Replicas of fractured smooth muscle cell plasma membrane showed caveola‐free regions with few intramembrane particles, interspersed with caveola‐populated areas with a higher intramembrane particle density. Electron microscopy of thin sections of quail gizzard smooth muscle revealed the regions free of caveolae to be occupied by membrane‐associated dense plaques; anchoring sites for the contractile filaments of the cell. Demarcation between the caveola‐populated and caveolafree regions on the relicated intramembrane surface was not clear and thus provided little information concerning the distribution of dense plaque sites. However, treatment of the smooth muscle tissue with the cholesterol‐binding agents filipin or tomatin prior to freeze‐fracture allowed the dense plaque sites to be easily observed as the sites remained free of the membrane deformations characteristic of these agents. The dense plaque sites consist of caveola‐free oval areas juxtaposed in regular bands that traverse the long axis of the cell. The dense plaque sites on the freeze‐fracture replica were confirmed by electron microscopy of thin sections of filipin‐treated quail gizzard smooth muscle cells, which showed the plasma membrane associated with the dense plaques to be unaffected by the actions of filipin, whereas that of the caveola‐populated region was severely deformed. The observations presented in this study provide evidence for a highly ordered distribution of dense plaques at the cell surface of intact quail gizzard smooth muscle cells and thus corroborate existing evidence for an organized substructure of smooth muscle cells.
Immunoelectron microscopic localization of laminin in rat ovarian follicles
Authors: Leardkamolkarn Vijittra , Abrahamson Dale R. 
Published: February 2005

AbstractWe studied the immunohistochemical and ultrastrural distribution of laminin in ovaries of immature and mature rats. When sections from 1–8‐week‐old rat ovaries were labeled directly with conjugates of affinity purified anti‐laminin IgG‐horseradish peroxidase (HRP), the antibodies bound to all ovarian basement membranes including those surrounding follicles in different stages of maturation. In addition, intracellular labeling was seen in granulosa and theca cells of follicles undergoing rapid development (preantral and antral stages) and in basement membrane‐like structures of the Call‐Exner bodies. Intracellular laminin was generally not detected, however, in any cells of primordial or atretic follicles. Tissue processed for immunoelectron microscopy 1 hour after the intravenous injection of anti‐laminin IgG‐HRP showed binding of antibody in linear patterns along endothelial and follicular epithelial basement membranes. Discontinuous strands of laminin‐positive, extracellular matrices were also seen between theca cells of all follicles. In addition, injected anti‐laminin IgG labeled perisinusoidal basement membranes located within corpora luteae and patches of basement membranes material between granulosa lutein cells. When ovaries were examined 5 d after the intravenous injections of anti‐laminin IgG‐HRP, uneven or segmented labeling was found in subepithelial basement membranes surrounding developing follicles. Our results therefore indicate that granulosa and theca cells participate directly in basement membrane laminin biosynthesis and suggest that this new laminin is spliced into existing basement membranes during follicular growth. © 1992 Wiley‐Liss, Inc.
Reexamination of the morphology of the extratesticular rete and ductuli efferentes in the goat
Authors: Goyal Hari O. , Hutto Victor , Robinson Danielle D. 
Published: February 2005

AbstractThe morphology of the extratesticular rete and ductuli efferentes was reexamined in serial cross sections collected from the entire mass of the efferent ductules and in longitudinal sections collected from the partially unraveled efferent ductules. The extratesticular rete forms a 3–4‐mm‐long sac‐like dilatation, which, within the head of the epididymis, has a wide lumen (up to 4 mm) and gives off along its length numerous evaginations, which, in turn, make connections with the ductuli efferentes. The latter is a mass of 16–18 ductules lined by three types of nonciliated cells: type II cells are characterized by dense, periodic acid‐Schiff (PAS)‐positive granules; type III cells are characterized by empty‐appearing, PAS‐negative vacuoles; and type I cells lack both granules and vacuoles. The distribution of the three types of nonciliated cells varies along the length. Whereas only type I cells are present in the beginning portion of the efferent ductule, type II cells predominate in the middle portion and type III cells in the distal portion (near the epididymis). The transition from one cell type to the other type is gradual; thus there are short segments along the length that share characteristics first for type I and type II cells and then for type II and type III cells. These results demonstrate that different nonciliated cell types are not randomly distributed in the epithelium of the ductuli efferentes but, instead, gradually differentiate from type I to type II to type III cells along the length of each efferent ductule. Factors controlling this differentiation remain to be studied. © 1992 Wiley‐Liss, Inc.
Penetration of the uterine epithelial basement membrane during blastocyst implantation in the mouse
Authors: Blankenship Thomas N. , Given Randall L. 
Published: February 2005

AbstractFor many species, blastocyst implantation is associated with a reduction in the number of cellular and extracellular matrix layers which separate the trophoblast from maternal vasculature. Following loss of uterine epithelial cells along the distal mural trophoblast, the mouse blastocyst encounters the residual epithelial basement membrane. This sheet of extracellular matrix must be breached and later removed prior to trophoblast invasion of the uterine stroma and formation of the placenta. The interactions between the trophoblast, luminal epithelial basement membrane, and decidual cells during the time when embryonic and uterine stromal cells first achieve contact were examined in this study.Distal mural trophoblast of activated delay blastocysts was in contact with the residual luminal epithelial basement membrane 36 hr after estrogen administration. This portion of the basement membrane contained areas in which the usual linear appearance was changed to an irregular, tortuous profile. The lamina densa frequently appeared flocculent and diffuse. Cytoplasmic processes from trophoblast and decidual cells simultaneously perforated the basement membrane at multiple discrete loci. With further development the basement membrane was lost, leaving trophoblast and decidual cells in close contact over large areas.In normally implanting blastocysts a similar stage of embryonic development, as described above, was attained by 0400 hr on day 6 of pregnancy. Regions of convoluted epithelial basement membrane were also seen in these implantation sites. However, only decidual cell processes were seen penetrating the residual basement membrane. These processes extended to the fetal side of the basement membrane and separated that matrix from overlying trophoblast. They contained organelles and formed rudimentary intercellular junctions with the trophoblast. It is concluded that decidual cells play an active role in the penetration of the epithelial basement membrane and may aid in its disintegration. © 1992 Wiley‐Liss, Inc.
Anatomical and immunohistological demonstration of the primary neural connections of the vomeronasal organ in the dog
Authors: Salazar Ignacio , Barber Peter C. , Cifuentes José M. 
Published: February 2005

AbstractMacro‐ and microdissection methods together with conventional histology and lectin immunohistochemistry have been used to identify the course of the vomeronasal nerves and their site of termination (accessory olfactory bulb; AOB) in the dog. The AOB in this species is small and variable in size, situated on the medial surface of the main olfactory bulb, and has an anatomical structure unlike that described for other mammals. The vomeronasal nerves and their terminal glomeruli in the AOB are easily identifiable by selective immunohistochemical staining using Ulex europeus agglutinin I. © 1992 Wiley‐Liss, Inc.
Endothelial cells and hematopoiesis: A light microscopic study of fetal, normal, and pathologic human bone marrow in plastic‐embedded sections
Authors: Islam Anwarul , Glomski Chester , Henderson Edward S. 
Published: February 2005

AbstractThe origin and morphological identity of hematopoietic progenitor cells, as well as their precursor, the pleuripotential hematopoietic stem cell (HSC), has not been established. Our studies of 2 μm sectioned undecalcified plastic‐embedded bone marrow (BM) from healthy human fetuses; normal adults; patients with acute myeloblastic leukemia (AML), acute lymphoblastic leukemia (ALL), and chronic granulocytic leukemia (CGL) in various stages (chronic, accelerated, acute blastic phase, and after autografting); and patients recovering from therapy‐induced marrow hypoplasia suggest that proliferative hematopoietic zones exist near the endosteum (endosteal marrow) and the vascular endothelium (capillary and sinus‐lining endothelium) and a maturational zone distal to these regions. In some of these areas, morphologically recognizable hematopoietic cells were seen and interpreted as emerging and maturing in a sequential progression, suggesting an origin from the endosteal or endothelial progenitors. In other loci, early hematopoietic cells were seen in close contact with the endosteal or vascular endothelial (VE) cells. This latter relationship suggested that these areas of cellular contact were important and represented sites of cell to cell interaction that may be associated with the liberation of growth factors by endosteal and endothelial cells and their action on hematopoietic progenitor cells. Following treatmentinduced hypoplasia, the endosteal and VE cells were seen to modulate, transform, and migrate into the surrounding empty and edematous marrow space as fibroblasts. Later, as hemopoietic regeneration began, clusters of regenerating hematopoietic cells were seen adjacent to bone trabecule (BT) and near the vascular endothelium. We postulate that endosteal and VE cells are the equivalent of embryonal‐stage, undifferentiated mesenchyme and, under the appropriate regulatory influence, are capable of modulation and transformation (differentiation) into stromal (fibroblast‐like) cells and precursors of hematopoietic cells in normal (physiologic) and stressed (pathologic) conditions. Recently, human endothelial cells have been shown to express a large number of cell surface antigens in common with hematopoietic (myeloid and lymphoid) cells. It is also possible that, in some situations, the VE cells act to establish a microenvironment and liberate growth factor (s), enabling pleuripotential and progenitor cell differentiation into mature hematopoietic cells adjacent to the vascular endothelium. Indeed, vascular endothelium has been shown to elaborate growth factors that participate in normal hematopoiesis. © 1992 Wiley‐Liss, Inc.
Ultrastructural characteristics of glomus cells in the external carotid artery during larval development and metamorphosis in bullfrogs, Rana catesbeiana
Authors: Kusakabe Tatsumi 
Published: February 2005

AbstractElectron microscopic observations of the external carotid artery in the larvae of the bullfrog, Rana catesbeiana, showed that glomus cells are present in the subendothelial stroma of the septum between the expanded region of the external carotid artery and the carotid arch. There were some differences in the ultrastructure of the glomus cells at each stage of larval development. At the early stages (stages I, III, V, X), most glomus cells were isolated and free from the covering of a supporting cell. The cytoplasm of the glomus cells contained fewer dense‐cored vesicles. No synaptic junctions were observed. At the middle stages (stages XV, XX, XXI), some glomus cells showed a tendency to form small clusters. Between adjacent cells in a cluster, gap junctions were often observed. The number of dense‐cored vesicles increased remarkably. Intimate apposition of the glomus and smooth muscle cells (g‐s connection) was also observed. Nerve terminals containing clear vesicles were observed in synaptic contact with glomus cells at this phase.At the metamorphic climax (stages XXII–XXV), in addition to g‐s connections, the glomus cells made intimate apposition to the cells around the glomus cells. The afferent synapses described in other amphibians were not encountered in this study.These findings suggest that the glomus cells at the early stages of development are nonfunctional, the vascular regulation via the g‐s connection starts at the middle stages, and the chemoreception starts after metamorphosis. © 1992 Wiley‐Liss, Inc.