bluuebunny/crossref_metadata_2025_split huggingface dataset:
Late skeletal development at the articulation between upper pharyngeal jaws and neurocranial base in the fish, Astatotilapia elegans, with the participation of a chondroid form of bone
Authors: Huysseune A. 
Published: February 2005

AbstractThis paper presents light‐microscopical details of the late development of skeletal tissues at the joint between upper pharyngeal jaws (UPJs) and neurocranial base (parasphenoid and basioccipital bones) in the acellular‐boned teleost Astatotilapia elegans. On each of the supporting elements, a bone tissue (AB) is deposited that is anomalous because of its retention of cells within the matrix. Later, this layer is gradually replaced by the anomalous large‐celled chondroid kind of bone (CB). Both AB and CB probably grow by apposition from the overlying fibrous layer. Osteoblastlike cells secrete osteoid, which soon calcifies and traps the cells. As in young cellular membrane bone, cells in the AB have a wide, elongate shape and lie amidst sparse, calcified, bonelike matrix but lack a canalicular system. Later generations of enclosed cells have a more vesicular shape, with at least some cells remaining alive in the calcified matrix. Appositional growth of the chondroid bone at its articular side is matched from a certain stage onward by erosion at its basal side. On the upper pharyngeal jaws this resorption is clearly related to the development of new teeth. Although in older stages and adults the chondroid tissue resembles a secondary cartilage, the term chondroid bone (CB) was preferred because of (1) the continuing formation by osteoblastlike cells; (2) the staining affinities of its matrix with that of bone; and (3) its formation both on cartilage bone (the infrapharyngobranchials III‐IV and basioccipital bone) and on membrane bone (the parasphenoid bone).
Enzymatic heterogeneity of the capillary bed of rat skeletal muscles
Authors: Mrázková Olga , Grim Miloš , Carlson Bruce M. 
Published: February 2005

AbstractThis study of the capillaries in rat skeletal muscle involved the use of a histochemical method that allows one to distinguish between arterial and venous portions of capillaries. Under controlled staining conditions, the arterial portion of the capillary bed reacts positively for alkaline phosphatase (AP) activity, and the venous portion is positive for dipeptidylpeptidase IV (DPP IV) activity. A short transitional capillary segment is positive for the activity of both enzymes. Capillaries of the normal soleus muscle and the red and white portions of the sternomastoid muscle have been quantitatively analyzed. Quantitative data demonstrated differences in capillary dimensions among the muscles studied. Capillaries of the white part of the sternomastoid were the longest, and they had the shortest DPP IV‐positive segment (8% of the total capillary length). Capillaries of the soleus muscle were the shortest, and they also had short DPP IV‐positive segments (16%). In contrast, the DPP IV‐positive segments of the red part of the sternomastoid occupied 60% of the total capillary length. Survey cross sections reveal a mosaic distribution of patches of capillaries stained for AP and DPP IV activity. This study reveals that within given bundles of muscle fibers, the capillaries that run parallel to the muscle fibers are aligned relative to one another in such a manner that their arterial and venous segments are in register.
Measuring histological form change with finite element methods: An application using diazo‐oxo‐norleucine (DON)‐treated rats
Authors: Lozanoff Scott , Diewert Virginia M. 
Published: February 2005

AbstractAnalyses of drug‐induced anatomical malformations routinely rely on linear measurements as a data base. Morphometric approaches utilizing these measures become inappropriate at the histological level at which a constant external referencing system is impossible to achieve. The purpose of this study was to quantify anatomical form change in the craniofacial region of late embryonic rats induced by a known teratogen, diazo‐oxo‐norleucine (DON), independent of any global referencing system. A sample of 17 untreated specimens of 17‐day gestation served as the control. A second group, equivalent in number and age, received 2.0 mg DON on day 15. Homologous landmarks were identified in each specimen and craniofacial regions were partitioned with respect to these bounding nodes into nasal, oral, and mandibular elements. Form change was viewed as the continuous deformation of a reference craniofacial region from a 15‐day untreated specimen into each final 17‐day geometry. An interactive graphics program generated spatially invariant measures of form change through finite element methods. A local coordinate system was established for each element. A point within each region of the 15‐day reference specimen was selected and the spatial relationship between this point and bounding nodes was quantified through interpolation functions. Size and shape variables were derived from a Lagrangian strain tensor, and values were compared between groups. Results showed that all three craniofacial regions were smaller in size among DON‐treated specimens, but only oral and mandibular region shapes were different from controls. The finite element approach was considered superior to other histological morphometric techniques since an entire geometry was described and a visual description of form change as well as spatially invariant measures of size and shape change were derived.
Gill ultrastructure of the pacific hagfish Eptatretus stouti
Authors: Mallatt Jon , Paulsen Charles 
Published: February 2005

AbstractAt the gross anatomical level, hagfish gills show unusual features not seen in any other fish gills. Our study was undertaken to determine if peculiarities also characterize the microscopic anatomy and ultrastructure of hagfish gills. To the contrary, branchial respiratory lamellae of Pacific hagfish were found to resemble the lamellae of lampreys, elasmobranchs, and teleosts, often down to the finest subcellular details. As in other fish, hagfish lamellae are lined by epithelium containing pavement cells with organelles indicative of a secretory function, basal cells showing undifferentiated cell features, and branchial ionocytes. The ionocytes are identical to chloride cells of teleosts in cytostructure, distribution, and abundance. There are pillar and marginal capillaries in hagfish gill lamellae. Pillar cells contain bundles of 5‐nm microfilaments, and they associate with collagen collagen columns as in other fish. Hagfish pillar cells do exhibit odd features, however: They cluster (groups of up to nine were seen), and their extracellular collagen columns are rarer than in other fish gills (averaging only two columns per three pillar cells). Other special features of hagfish gills are the following: (1) lipid droplets and smooth endoplasmic reticulum are well developed in all cell types; (2) pavement cells secrete a lipomucous product (stains with periodic acid‐Schiff, Alcian blue, and Sudan black B); and (3) goblet cells are absent. The presence of “chloride cells” in hagfish is puzzling, as hagfish body fluids are iso‐osmotic to seawater and there is no need to osmoregulate for sodium chloride; the ionocytes contain carbonic anhydrase, suggesting a function in acid/base regulation.
A description of caudal migration during growth leading to the formation of the pericardial and pleural coeloms, to caudal movement of the aortic arches, and to development of the shoulder
Authors: Searls Robert L. 
Published: February 2005

AbstractFormation of the shoulder in the chick embryo results from movement of cells into the base of the wing from more cranial regions. Between stage 23 and stage 27, the lateral body wall overlying the pleural coelom is caused to move into the base of the wing because the cranial margin of the pleural coelom moves from the level of the tenth somite to the level of the 16th somite. Thus, formation of the shoulder is related to the formation of the pleural coelom. Textbook descriptions of the formation of the pleural coelom did not permit this relationship to be delineated. Therefore, investigation of the relationship between the formation of the shoulder and the formation of the pleural coelom seemed warranted. At stage 12 the coelom is lateral to the gut from the level of the second somite to the level of the 16th somite and is continuous with the extraembryonic coelom. During stage 13 the coelom obtains a ventral margin at the level of the third and fourth somites as the heart fuses with the lateral body wall to form the lateral mesocardium. Between stage 16 and stage 23, the second (cervical) flexure develops, causing the lateral mesocardium to form a ventral margin of the coelom from the level of the first to the 17th somites. Between stage 16 and stage 23, the coelom becomes ventral to the pharynx and lung to the level of the ninth somite. From stage 23 to stage 27, the lateral body wall from the cranial margin of the lung to the caudal margin of the hyoid arch moves in a caudal direction. During stage 27, the lateral body wall fuses with the lateral mesocardium to form the pleuro‐pericardial membrane. The wing remains ventral to the 16th to 19th somites, causing a pileup of cells at the cranial base of the wing, the shoulder.
The ontogeny of the mouse estrogen receptor: The pelvic region
Authors: Holderegger C. , Keefer D. 
Published: February 2005

AbstractThe appearance of estrogen receptors was examined during the course of fetal and neonatal development in the pelvic region of the mouse; 3H‐diethylstilbestrol (DES) was administered via the maternal circulation to developing mice on days 4, 7, 10, 13, 14, 15, and 17 of gestation or to neonates on the day of birth. Localization of the ligand was monitored autoradiographically. The earliest appearance of estrogen receptors occurred in the mesenchyme around the genital ducts on day 13 of pregnancy. On subsequent days, estrogen‐concentrating cells appeared in certain mammary‐gland cells, connective‐tissue strands, in perichondrium associated with specific developing bones, skin, interstitial tissue of the testis, in a sheath of cells surrounding the colon, and in the urethra. The significance of cells containing estrogen receptors in these locations is discussed in reference to a transplacental action of estrogens and the clinical ramifications of DES.
Distribution of hyaluronic acid and sulfated glycosaminoglycans during blood‐vessel development in the chick chorioallantoic membrane
Authors: Ausprunk Dianna H. 
Published: February 2005

AbstractThis study uses histochemical methods to determine the ultrastructural distribution of specific glycosaminoglycans (GAGs) during the development of blood vessels in the chick chorioallantoic membrane (CAM) and to correlate changes in GAG composition with the significant structural events in the development of these vessels. Tissues were stained with tannic acid, ruthenium red, and high iron diamine and digested in various GAG‐degrading enzymes to identify specific GAGs. The results are consistent with a role for hyaluronic acid in the formation, alignment, or migration of the capillary plexus of the CAM and a role for sulfated GAGs (heparan sulfate, chondroitin sulfate, dermatan sulfate) in the differentiation and development of arterial and venous vessels of the chorioallantoic membrane.
Mapping of the rat liver endothelial membrane with lectins and glycosylated ferritins
Authors: Irie Seiji , Tavassoli Mehdi 
Published: February 2005

AbstractWe explored the luminal surface of liver sinus endothelium for the presence of lectin receptors and lectinlike substances capable of interacting with specific sugars. We used ferritin‐conjugated lectins and glycosylated ferritins as probes. Incubation of small blocks of rat liver with these probes led to the binding of concanavalin A (on A), Ricinus communis (RCA), wheat germ agglutinin (WGA), phytohemagglutinin (PHA) and mannosyl ferritins to the luminal surface of endothelium. Ulex europaeus agglutinin I (UEA), fucosyl, galactosyl, and chitobiosyl‐ferritins did not bind. The binding was patchy and sparse in the case of Con A and mannosyl‐ferritins but uniform for others. Binding density did not correlate with hemagglutinability of lectins, suggesting that the difference in the hemagglutinability of these lectins did not account for the difference in their binding densities. Bindings were all completely inhibited in the presence of excess specific sugar inhibitors, indicating the specificity of binding. The distribution of binding was segregated on the endothelial membrane, being heaviest on luminal pits. To define the functional significance of this segregated distribution, sinus endothelium was compared to portal‐vein endothelium in which endothelial fenestrations are also seen; and these fenestrations as well as pits may be covered by a thin diaphragm. Of interest was the total absence of binding to the diaphragm. The significance of these findings is discussed.
Morphometry of the coronary microvasculature of the canine left ventricle
Authors: Hyde Dallas M. , Buss Daryl D. 
Published: February 2005

AbstractThe objective of this study was to test for the presence of transmural gradients of various components of the coronary microvasculature of the canine left ventricle. In order to achieve study objectives, the heart and coronary circulation were fixed in a reproducible state of myocardial and vascular tone (diastolic cardiac arrest and maximal coronary vasodilation). Morphometric methods which treat the coronary microvasculature as anisotropically arranged structures were applied for quantitative structural analysis. Eight dog hearts were fixed with a glutaraldehyde‐cacodylate‐buffered fixative by retrograde perfusion of the aorta with the heart in diastolic arrest and with maximal coronary vasodilation. Tissue samples were taken from areas near to the anterior and posterior papillary muscles from the subendocardium, subepicardium, and intermediate transmural locations. Morphometric results showed a homogeneously arranged array of microvascular and myocardial components with no significant differences in any of the primary morphometric measurements, down to the ultrastructural level, in myocytes relative to transmural location. The results suggest that transmural differences in coronary blood flow are not due to transmural structural differences but rather are due to physiological regulatory mechanisms of coronary blood flow. Further, the results indicate that failure to correct for anisotropy of myocardial structures can lead to erroneous conclusions concerning the structural basis of function in the heart.
Ultrastructure of alveolar bone during tooth eruption in the dog
Authors: Marks Sandy C. , Cahill Donald R. 
Published: February 2005

AbstractPrevious work from our laboratories has established that eruption of the permanent mandibular premolars in dogs is dependent upon the presence of the dental follicle and that it involves resorption of alveolar bone and the roots of the deciduous predecessor above and formation of alveolar bone below the developing crown. This study illustrates the topography of the bone surfaces of the crypt by scanning electron microscopy and the ultrastructure of the cells on alveolar bone surfaces during tooth eruption. Above the developing crown where the eruption pathway forms, the bone surface is a pitted sheet, the characteristic topographic feature of bone resorption; between the crown and the mandibular canal, the bone surface has numerous interconnecting trabeculae. Transmission electron microscopy of bone cells lining the eruption pathway area of the crypt showed numerous osteoclasts with adjacent mononuclear cells. Both cell types contained specific, membrane‐bound cytoplasmic vesicles shown by the work of others to be characteristic features of osteoclasts and their precursors. Basal trabeculated bone in the crypt was covered by plump osteoblasts. These data show that the metabolic events in alveolar bone associated with tooth eruption have the appropriate cellular and bony surface correlates and that the suspected control of alveolar bone resorption by the dental follicle may be mediated by its recruiting and directing to adjacent bone surfaces the mononuclear precursors of osteoclasts.
Expression of nuclear estrogen‐binding sites within developing human fetal vagina and urogenital sinus
Authors: Taguchi Osamu , Cunha Gerald R. , Robboy Stanely J. 
Published: February 2005

AbstractAn autoradiographic study of nuclear estrogen binding was performed in developing human urogenital sinuses and vaginas derived from first and second trimester specimens. Nuclear estrogen binding was detected in all specimens ≥ 10 weeks of gestation within mesenchymal cells. Nuclear labelling within epithelium was observed only in those specimens whose development and differentiation was advanced. Thus, mesenchyme appears to be the initial estrogen target tissue within the developing human vagina and may play a fundamental role in estrogen‐induced teratogenesis of the human genital tract.
Ultrastructure of the giant cell infiltrate of subcutaneously implanted bone particles in rats and mice
Authors: Popoff Steven N. , Marks Sandy C. 
Published: February 2005

AbstractThe giant cells of soft tissues and those of mineralized tissues (osteoclasts) have distinctly different cell surface receptors and ultrastructural characteristics. Recently, the removal of dead bone particles in a subcutaneous environment has been described as a prototype of bone resorption, and a major issue is whether the giant cells that surround these ectopic bone implants and the processes involved in the disruption of bone surfaces are the same as those in the skeleton. We have compared the cytology and ultrastructure of giant cells recruited to subcutaneously implanted isogeneic bone particles with similar features of osteoclasts in metaphyseal bone of young normal rats and mice. Giant cells on surfaces of bone particles 2, 3, and 4 weeks after implantation were multinucleated, had a homogeneous, nonvacuolated cytoplasm, and had a bone surface interface unremarkable by light microscopy. In a few cells randomly distributed, small cytoplasmic vacuoles were present and large vacuoles were noted next to the bone surface at high magnification. By transmission electron microscopy, folded membrane configurations forming extensive interdigitations with adjacent cells were prominent features on most surfaces of giant cells. In instances where these interdigitations abutted bone surfaces, configuration resembling a ruffled border were noted, but these regions were always part of two different cells when examined at lower magnification or in serial sections. Breakdown of bone particles appeared to be by phagocytosis of small pieces and subsequent intracellular digestion in electron‐dense cytoplasmic vacuoles. Osteoclasts from these same young animals were smaller with fewer nuclei, had cytoplasmic vacuoles concentrated next to bone surfaces, and had characteristic ruffled borders and clear zones. These results confirm those of others that native osteoclasts and multinucleated giant cells on dead bone particles are distinctly different with respect to both ultrastructure and mechanism of disruption of bone surfaces.
The correlation between craniofacial and long bone growth: An experimental investigation in normal rabbits
Authors: Alberius Per , Isberg Per‐Erik 
Published: February 2005

AbstractThe present study was undertaken to elucidate the relationships between craniofacial and long‐bone growth. Nine male New Zealand white rabbits received spherical tantalum bone markers in the tibial epiphyses and in the nasal, frontal, and parietal bones. The animals were followed from 30 to 143 days of age. Growth changes were calculated with a roentgen stereometric system, and the results statistically evaluated. Except for the final interval when all variables varied at random, high correlations between tibial and frontonasal or coronal sutural growth were demonstrated; and the respective linear regression lines were homogenously assembled. The relationship between the tibia and the sagittal suture displayed great variations between individual animals as well as between the suture's parts, although growth at the interfrontal suture was clearly correlated to tibial growth upon exclusion of the time factor. The first principal component of the three neurocranial sutures was calculated and seemed accurately correlated to longbone growth. The present study concluded that growth at the frontonasal and coronal sutures normally seems to parallel general somatic development, while growth at the sagittal suture appears individually displaced in time. Nevertheless, when the principal component of the combination of the coronal suture and the neurocranial section of the sagittal suture was computed, this was highly correlated to body growth.
Intraventricular neuronal complex of the lamina terminalis of the mouse
Authors: Bleier Ruth , Siggelkow Inge 
Published: February 2005

AbstractAn intraventricular neuronal complex has been identified with scanning and transmission electron microscopy at the base of the lamina terminalis of the mouse. The raspberry‐shaped complex protudes from a thickened bulge on the ependymal surface of the lamina terminalis or adjacent rostral floor of the third ventricle. Neurons and occasional ependymal cells cover the surface of the complex. Its core is made up of neurons, ependymal cells, and neuronal processes, which are usually compactly arranged. The core is continuous, through a breach in the ependymal layers, with the subependymal neuropil of the lamina terminalis. Within the core of the complex are large numbers of axodentritic synapses. Axonal varicosities and synaptic terminals are filled with vesicles and mitochondia. Synaptic endings have one of two populations of vesicles: exclusively clear, small, round or flattened vesicles. In view of the known structural and functional characteristics of the lamina terminalis, it is possible that the neuronal complex may participate in neurohormonal regulatory systems of the hypothalamus and hypophysis or in the network of circumventricular organs mediating angiotensin effects.
Circular polysomes predominate on the rough endoplasmic reticulum of somatotropes and mammotropes in the rat anterior pituitary
Authors: Christensen A. Kent , Kahn Larry E. , Bourne Carol M. 
Published: February 2005

AbstractWe have studied the shape and size distribution of membrane‐bound polysomes in somatotropes and mammotropes, which are the sources, respectively, of growth hormone and of prolactin in the rat pituitary. The observations were made in conventional electron micrographs of these cells in situ, where occasional surface or en face views of the rough endoplasmic reticulum allow the polysomes to be seen as rows of ribosomes arranged in distinctive patterns on the membranes. It is possible by this means to characterize the shape and number of ribosomes for the total population of bound polysomes in the respective cell types.The great majority of membrane‐bound polysomes in these two cell types (81% in somatotropes, 78% in mammotropes) have an approximately circular shape and contain an average of 6.8 (somatotropes) or 6.5 (mammotropes) ribosomes, which is an appropriate size for translation of the polypeptide hormones produced by these cells. About 17% of the membrane‐bound polysomes in somatotropes and 20% in mammotropes have a spiral shape, resembling somewhat the letter “G,” and contain about eight to nine ribosomes in both cell types.The preponderance of circular polysomes on the rough endoplasmic reticulum of somatotropes and mammotropes suggests the possibility that ribosomes (or the 40S ribosomal subunit) may recycle on the polysome after the translation of growth hormone or of prolactin.