bluuebunny/crossref_metadata_2025 huggingface dataset:
Location of the motoneurons supplying the rabbit pharyngeal constrictor muscles and the peripheral course of their axons: A study using the retrograde HRP or fluorescent labeling technique
Authors: Kitamura Seiichiro , Ogata Kimio , Nishiguchi Takahiko , Nagase Yoshitaka , Shigenaga Yoshio
Published: February 2005

The location of the motoneurons supplying the rabbit pharyngeal constrictor muscles (the superior and the middle constrictors, and the thyropharyngeus and the cricopharyngeus; the last two collectively compose the inferior constrictor) was investigated with intramuscular injection of HRP or the fluorescent tracer nuclear yellow into the individual muscles. Moreover, the peripheral course of their axons was investigated by injection of HRP into all of the pharyngeal constrictors in conjunction with intracranial severing of either the vagus or the glossopharyngeal nerves. The pharyngeal constrictor motoneurons were ipsilaterally located within a subdivision of the nucleus ambiguus which is formed by a compact arrangement of the smallest neurons of the nucleus and situated in the rostral half of the nucleus. We named that subdivision the compact cell group (CoG). Axons of the pharyngeal constrictor motoneurons traversed the vagal rootlets. The rostrocaudal extent of the pharyngeal constrictor motoneurons covered almost the entire length of CoG at a level from about 500 to 2,900 μm rostral to the obex, with their number being most numerous in the middle one‐third level of the CoG. Although the motoneurons of the superior constrictor, those of the middle constrictor, and those of the thyropharyngeus and the cricopharyngeus overlapped considerably in location, they tended to be arranged rostrocaudally in that order. At the middle one‐third level of the CoG, where the CoG is subdivided into dorsomedial and ventrolateral subgroups of neurons, the superior and the middle constrictor motoneurons were confined to the medial portion of the dorsomedial subgroup, while the inferior constrictor motoneurons were distributed throughout its entirety.
Cytoskeleton in microridges of the oral mucosal epithelium in the carp, Cyprinus carpio
Authors: Uehara Kiyoko , Miyoshi Masayuki , Miyoshi Sakuichiro
Published: February 2005

Microridges produce a characteristic fingerprint‐like pattern on the surface of fish oral mucosa. The cytoskeleton in these microridges was examined by immunofluorescence microscopy and transmission electron microscopy after detergent extraction and decoration with myosin subfragment 1. The effect of cytochalasin B on microridges was probed with scanning electron microscopy. Immunofluorescence microscopy revealed that actin filaments were present throughout the periphery of the epithelial cells and were especially localized beneath the free surface of the epithelium. In thin sections treated with Triton X‐100, the majority of filaments in the microridges and their bases were found to be actin filaments and a plexus of keratin filaments that underlay the network of actin filaments. A part of the plexus of keratin filaments entered the microridges. After extraction with Triton X‐100 and decoration with myosin subfragment 1, decorated actin filaments were found in the microridge cores, connected to the keratin filaments. The keratin filaments aggregated in the pattern of microridges and a few of them protruded into the microridges. Treatment with cytochalasin B caused microridges to disappear or to become thinner and lower or to change short or microvillus‐like microridges. When most microridges disappeared, the surface of the superficial cells was prominently swollen, but the cell boundaries were fastened, and the microridges in the periphery were preserved. On the basis of these observations, the possible roles of actin and keratin filaments in the maintenance and the formation of microridges are discussed.
Colloidal gold localization of type IV collagen in the extracellular matrix of rat gastric mucosa: Influence of alcohol and prostaglandin
Authors: Rightor Kathryn S. , Mitchell Philip A. , Miller Thomas A. , Schmidt Karmen L.
Published: February 2005

The effect of acute alcohol exposure on the gastric mucosal basal lamina, and its major structural protein type IV collagen, was assessed by transmission electron microscopy (TEM) and immunogold (IG) labeling of this collagenous material. Fasted rats orally received either 50% or 100% ethanol. Five or 60 minutes later animals were sacrificed and mucosal samples were obtained from the glandular epithelium for TEM or IG localization of type IV collagen. For IG studies, the number of gold particles/area lamina densa was quantified in interfoveolar, pit, and gland regions as an index of the molecular integrity of type IV collagen. Both ethanol concentrations induced epithelial exfoliation with pleating of the denuded lamina densa. Absolute ethanol, and to a lesser extent 50% ethanol, caused frequent rupture of a thickened, precipitated lamina densa. Immunolabeling of type IV collagen varied with the experimental protocol. In control tissues exposed to oral saline, binding was greatest in the interfoveolar zone. Low binding occurred with 100% ethanol in all regions when compared with controls, but 50% ethanol evoked significantly higher binding in interfoveolar regions, in a similar fashion to controls. In additional studies in which 16,16 dimethyl prostaglandin E2 (PGE2) (10 μg/kg) was injected subcutaneously prior to oral ethanol exposure, PGE2 pretreatment prevented the large decrease in IG binding induced by absolute ethanol, but the level still remained significantly less than with corresponding controls. In contrast, pretreatment with PGE2 prior to 50% ethanol exposure restored type IV collagen immunolabeling to control levels. These results indicate that ethanol induces a concentration‐dependent lowering of IG binding to type IV collagen which also effects its reversibility by PGE2.
Freeze‐fracture observations on human fetal kidney in serum‐free organ culture
Authors: Brière Normand , Cabana Charles , Magny Pierre
Published: February 2005

The current study was undertaken to examine and characterize junctional complexes, through freeze‐fracture, in developing human fetal kidney and in cultured renal explants maturing in vitro. Tissue specimens were cultured for 7 days in Leibovitz's L‐15 medium in the absence of serum or hormones. In uncultured explants, cells in the different nephron segments were joined by zonulae occludentes which consisted of ridges on the P‐face and grooves on the E‐face of lateral membranes. Tight junction composition was heterogeneous and complexity increased from proximal to collecting tubules. Proximal tubule cells were also characterized by the presence of gap junctions and a brush border. Podocytes were joined by macular junctions, while zipper‐like junctions were observed between collecting duct cells. Intercalated cells were decorated with rod‐shaped intramembrane particles on lateral and apical membranes, instead of the usual spherical particles present in other cells. All these structures could be observed at various intervals during tissue culture, indicating the preservation of ultrastructural integrity of the explants. These observations extend and support previous studies made at the light and electron microscopic levels. Thence, the present culture model constitutes a valuable tool to study the direct effect of growth factors on nephrogenesis.
Characteristics of end‐plates formed in mouse skeletal muscles reinnervated by their own or by foreign nerves
Authors: Bewick Guy S. , Tonge David A.
Published: February 2005

Morphological and electrophysiological techniques were used to study the neuromuscular junctions of soleus and extensor digitorum longus muscles in normal mice and 6 months after reinnervation by either their original or foreign nerves. In muscles reinnervated by foreign nerves, there were increased incidences of morphological abnormalities, including ultra‐terminal axonal sprouting, multiaxonal innervation of end‐plates, and ectopic synapse formation, as compared with both normal muscles and muscles reinnervated by their correct nerves. In spite of the morphological abnormalities, however, there was no evidence that the effectiveness of synapses (as estimated from the mean quantal content, m, of end‐plate potentials) formed between nerves and inappropriate muscles was impaired. As had also been found in normally innervated muscles, the value of m was again higher in extensor digitorum longus than in soleus following reinnervation by inappropriate nerves. These results suggest that in mammals, when muscles are reinnervated by foreign nerves, mechanisms exist to maintain the efficacy of neuromuscular transmission, in contrast to the situation in amphibians (Sayers and Tonge, 1982: J. Physiol. (Lond.), 330:57–68). The abnormalities observed in this study following reinnervation may be a morphological manifestation of these corrective mechanisms.
Changes of glycoconjugate contents of the zona pellucida during oocyte growth and development in the golden hamster: A quantitative cytochemical study
Authors: Roux Emmanuelle , Frederick W. K. Kan
Published: February 2005

We demonstrated here with the high resolution lectin‐gold approach and quantitative analysis, changes of glycoconjugates in the hamster zona pellucida (ZP) during oocyte growth and development in the ovary and the oviduct. Glycoconjugates which contain N‐acetyl‐D‐galactosamine as terminal sugar residues are absent in the ovary but are secreted by secretory cells in the oviduct and are added to the ZP of superovulated oocytes during oviductal transit. Glycoconjugates which carry sialic acid as terminal sugar residues appear to be acquired mainly from the ovary. The oviduct contributes little of this particular component to the ZP during the transit of oocytes in the oviduct. On the contrary D‐galactose and N‐acetylglucosamine associated glycoconjugates, added to the ZP in ovarian follicles, are also secreted by non‐ciliated oviductal epithelial cells and these secretory products are transferred to the ZP in significant amount during passage of the oocyte through the oviduct. Lectin‐gold labeling of the ZP of superovulated oocytes reveals homogeneous distribution of gold particles throughout the zona matrix. Thus, we conclude that the ZP of hamster superovulated oocytes consists of glycoconjugates that may derive from different origins. Deposition of ZP glycocomponents begins in the ovary. Similar and new glycoconjugates, secreted by oviductal non‐ciliated secretory cells, are added to the ZP of oocytes during oviductal transit. At this stage the ZP is made up of a homogeneous matrix of glycoconjugates.
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

This 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

Using 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

Interstitial 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

The 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

Brown 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

Satellite 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

The 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

The 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

We 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

The 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

For 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

Macro‐ 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

The 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

Electron 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.
Microcorrosion casts of hamster luteal and follicular vasculature throughout the estrous cycle
Authors: Forsman Allan D. , McCormack John T.
Published: February 2005

Golden hamster (Mesocricetus auratus) ovarian microcorrosion casts were studied as a model system to analyze angiogenesis that occurs in the corpus luteum (CL) during the estrous cycle. Growth of the vasculature in the hamster CL occurs rapidly with complete formation and subsequent degeneration occurring during the 4‐day estrous cycle. This study followed the growth of these vessels by casting the ovarian vasculature at 4‐hour intervals during the formation of the CL, viewing the casts on a Scanning Electron Microscope (SEM), and comparing the consecutive casts. This study revealed that the microvasculature of the CL forms rapidly from the vessels of the theca folliculi of newly ruptured follicles and that this growth is in an internal direction. This method of casting, when used in conjunction with the high magnification provided by the Hitachi field emission high resolution SEM, enabled us to analyze the growing tips of the vascular sprouts. The vasculature of the CL grows throughout day 1 and well into day 2 of the cycle. Flat veins, characteristic of the external suface of a mature CL, formed by the afternoon of day 2. Obvious degeneration of the vasculature of the CL took place throughout day 3. This study provided a detailed description of the angiogenesis that occurred throughout the rapid formation of the hamster CL and showed that this method produced casts of suitable quality for exprimental observations. © 1992 Wiley‐Liss, Inc.
Scanning and transmission electron microscopy of venous sphincters in the rat lung
Authors: Aharinejad S. , Böck P. , Lametschwandtner A. , Firbas W.
Published: February 2005

The rat pulmonary microvasculature was studied using scanning and transmission electron microscopy of vascular corrosion casts and tissue sections. Special emphasis was placed on small pulmonary venous vessels. The shape of vascular casts was analyzed and interpreted concerning the wall composition of corresponding vessels studied in tissue sections. On the casts of pulmonary venules and small pulmonary veins, narrow or wider annular constrictions were regularly observed. Within these constrictions, marks of circularly running grooves were seen as an additional structural detail, which obviously mimic impressions of single or grouped smooth muscle cells. The depth of the constrictions varies; it may be more or less pronounced, occasionally narrowing down the luminal diameter to approximately 50%. These constrictions are caused by muscular sphincters. In tissue sections of small pulmonary veins, sphincter regions were identified as abruptly appearing single or grouped true smooth muscle cells. Smooth muscle cells may be arranged side by side in a group or bundle or even staked in two or three layers. Between the sphincter regions, the venous wall consists merely of endothelium and an accompanying connective tissue layer. The smooth muscle cells of a sphincter are regularly positioned between endothelial layer and elastic lamina. The smooth muscle cells next to the endothelium form myoendothelial junctions. Autonomic nerves near the sphincters were never seen. The venous sphincters described are suggested to be effective devices involved in blood flow regulation. Blood‐borne substances or local tissue hormones might govern sphincter function. © 1992 Wiley‐Liss, Inc.
Immunocytochemical localization of rat intestinal 15 kDa protein, a member of cytoplasmic fatty acid‐binding proteins
Authors: Amano Osamu , Kanda Tatsuo , Ono Teruo , Iseki Shoichi
Published: February 2005

Rat intestinal 15 kDa protein (I‐15P) is a member of the family of cytoplasmic fatty acid‐binding proteins. Using a specific antiserum against I‐15P, we studied the tissue distribution and subcellular localization of this protein in the entire rat body. By immunoblot analysis of cytosolic proteins, I‐15P was detected not only in the distal portion of small intestine but also in the ovary and adrenal gland. Immunohistochemically, I‐15P was localized to the absorptive epithelial cells as well as a subpopulation of enterochromaffin cells in the intestine, the lutein cells in the ovary, and subpopulations of cortical cells in the adrenal gland. Furthermore, I‐15P‐like immunoreactivity was also demonstrated in the surface mucous cells of stomach and the granular convoluted tubule cells of submandibular gland. Immuno‐electron microscopy showed that the immunoreactivity was confined to the cytoplasmic matrix region, except in the enterochromaffin cells and granular convoluted tubule cells, where it was localized in the secretory granules. The present findings suggest that I‐15P plays a role in the cellular metabolism of steroids.© Willey‐Liss, Inc.
Adaptation of cancellous bone to aging and immobilization in growing rats
Authors: Chen Meng Meng , Jee Webster S. S. , Ke Hua Zhu , Lin Bai Yun , Li Qing Nan , Li Xiao Jian
Published: February 2005

Two‐and‐half month‐old female rats were subjected to right hindlimb immobilization or served as controls for 0, 1, 2, 8, 14, and 20 weeks. The right hindlimb was immobilized by bandaging it against the abdomen, thus unloading it. Cancellous bone histomorphometry was performed on microradiographs and double‐fluorescent labeled 20 μm sections of the distal femoral metaphyses. Primary spongiosa bone loss occurred rapidly by 2 weeks, and secondary spongiosa bone loss occurred rapidly by 8 weeks of immobilization, and then equilibrated at 60% less bone mass than age‐related controls. The negative bone balance induced by immobilization was caused by transient increase in bone resorption, decrease in bone formation, and longitudinal bone growth. The dynamic data of secondary spongiosa cancellous bone showed that percent eroded perimeter was transiently elevated by 55 to 82% between 1 and 8 weeks, percent labeled perimeter was transiently depressed by 32% to 50% between 1 and 14 weeks, mineral apposition rate was depressed by 23% and 19% at 1 and 2 weeks, and bone formation rate‐bone area referent was transiently depressed by 35% and 59% at 1 and 2 weeks. All the above parameters were at age‐related control levels by 20 weeks of immobilization. However, bone formation rate‐tissue area refent was depressed (‐65%) throughout the study. Immobilization depressed completely longitudinal bone growth by 2 weeks and remained so. Only 0.65 mm of new metaphysis was generated in the immobilized versus 2.1 mm in controls during the study period. The immobilization induced an early cancellous bone loss which equilibrated at a new steady state with less bone and a normal (age‐related control) bone turnover rate. When these findings were compared to an earlier study of 9‐month‐old virgin females subjected to right hindlimb immobilization up to 26 weeks, we found the adaptive responses of the cancellous bone were identical except that they occurred earlier and equilibrated sooner in younger rats.© Willey‐Liss, Inc.
Cystogenesis of the ovarian antral follicle of the rat: Ultrastructural changes and hormonal profile following the administration of dehydroepiandrosterone
Authors: Anderson Everett , Lee Mong‐Ting , Lee Gloria Y.
Published: February 2005

Immature 27‐day‐old female Sprague‐Dawley rats were administered daily subcutaneous injections of dehydroepiandrosterone (DHEA, 5 mg/100 g BW) to induce the formation of ovarian follicular cysts. Groups of rats were killed on days 0, 10, 15, 20, 25, and 30. Ovaries from each group of rats were processed for light and electron microscopy and for follicular or cystic fluid hormone analysis. Normal antral follicle fluid, PMSG‐treated preovulatory follicular fluid, and cystic fluids were analyzed for progesterone (P), estrone (E1), estradiol (E2), testosterone (T), Δ4‐androstenedione (Δ4‐A), 5α‐dihydrotestosterone (DHT), luteinizing hormone (LH), follicle stimulating hormone (FSH), and prolactin (PRL).

DHEA induced anovulation, acyclicity, and the formation of follicular cysts. In certain antral follicles, there was a dramatic increase in the quantities of smooth endoplasmic reticulum (SER) in the granulosa cells and many mitochondria had tubular cristae. Further depletion of granulosa cell number was associated with intense blebbing of the cytoplasm into the follicle antrum. Formation of the ovarian follicular cyst was completed when the entire cyst was lined by a single layer of transformed granulosa cells in contact via adhering, gap, and tight junctions. These cells had little cytoplasm, mitochondria with lamellar cristae, vast basal and apical bands of microfilaments, and an extensive array of smooth‐surfaced endocytotic invaginations on the basal plasma membrane. These endocytotic pits may subsequently form smooth‐surfaced vesicles and thereby serve as one mechanism for moving fluid from the ovarian interstitium into the cyst. Theca interna cells were rarely observed in the peripheral regions of the cyst. Abundant smooth muscle cells were located beneath the basement membrane of the epithelial cells comprising the cyst wall. These acquired morphological and physiological features may ensure persistence of the ovarian cyst and thus potentiate a chronic pathological condition.

In this study it was also shown that progesterone, estrone, and estradiol as well as androgen concentration increased in the follicle after PMSG treatment. With DHEA treatment, the follicular cystic fluid concentrations of these steroids progressively increased to extremely high levels concurrent with the development of the follicular cysts. With respect to pituitary protein hormones, there was no appreciable difference in FSH after PMSG treatment, while there was a decrease in LH and an increase in PRL.

The information reported in this and a previous study (Lee et al., Anat. Rec., 231:185–192, 1991) suggests that the ovarian cystic condition that developed after DHEA treatment in rats is associated with elevated levels of circulating serum prolactin and androgens, and extremely high concentrations of steroids as well as FSH and LH in the follicular/cystic fluid.© Willey‐Liss, Inc.
High‐resolution immunolocalization of osteopontin and osteocalcin in bone and cartilage during endochondral ossification in the chicken tibia
Authors: McKee M. D. , Glimcher M. J. , Nanci A.
Published: February 2005

The ultrastructural distribution of two noncollagenous proteins, osteopontin (OPN) and osteocalcin (OC), originally extracted from bone matrix and proposed to play an important role in bone formation, was examined in the matrices of bone and cartilage from embryonic and postnatal chicken tibial growth plates by high‐resolution immunocytochemistry using the colloidal gold technique. In bone, immunolabeling patterns using polyclonal antibodies against chicken OPN and OC were generally similar in that both showed an intense, but regionally variable, labeling of mineralized bone matrix and small mineralization loci dispersed throughout the osteoid and containing prominent condensed organic material. Unmineralized osteoid showed weak‐to‐moderate labeling. In the mineralized bone matrix proper, labeling was predominantly associated with amorphous, electron‐dense patches of organic material among the collagen fibrils. In growth plate cartilage, both proteins first appeared related to calcified cartilage in the hypertrophic zone, although the labeling patterns were somewhat different. For OPN, gold particles were mostly associated with an organic lamina limitans‐like density containing condensed, filamentous organic matrix at the periphery of small nodules and large masses of calcified cartilage, with additional moderate labeling throughout the interior of the calcified cartilage. For OC, labeling was observed over filamentous structures throughout the calcified cartilage matrix, with some, but less, labeling at the periphery. In the lowermost zones of the growth plate, the major reaction using both antibodies was found over a layer of dense, amorphous organic material at the periphery of the calcified cartilage at the future bone/calcified cartilage interface, a labeling pattern that persisted following bone deposition at these sites. OPN and to a lesser extent OC were also concentrated in cement (resting, reversal) lines. Throughout the bone and cartilage of the tibia, cells of both the osteoblastic and the osteoclastic lineages were found directly apposed to labeled surfaces and lamina limitans of organic matrix containing OPN and OC. In summary, it is concluded form the immunocytochemical data presented here that the association of OPN and OC with mineralized regions of the extracellular matrices of bone and cartilage and the accumulation of these proteins at tissue surfaces and interfaces are consistent with the hypotheses that they play a role in the extracellular mineralization process per se and/or that they may mediate cell adhesion and dynamics.© Willey‐Liss, Inc.