bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of the rat meninx: Exerimental study using bromodeoxyuridine
Authors: Kamiryo Toshifumi , Orita Tetsuji , Nishizaki Takafumi , Aoki Hideo 
Published: February 2005

AbstractThe development of the rat meninx from the viewpoint of cell proliferation was studied microscopically and immunohistochemically using bromodeoxyuridine (BUdR). A compact cell layer around the neural tube, the meninx primitiva, was observed in 12‐ and 13‐day fetuses. A reticular structure resembling the subarachnoid space appeared in the 14‐day fetus. The ectomeninx, consisting of a collagen fiber layer, part of which became the dura mater, appeared in 15‐day fetuses, allowing discrimination of the endomeninx, the arachnoid cell layer. The primordium of the choroid plexus also appeared in the lateral ventricle on the same day. Bone appeared in the primitive dura mater, and stratification of the meninx was almost complete in 21‐day fetuses. BudR‐positive cells were confirmed in the meninx from day 12 of gestation to day 15 postpartum. The number of BudR‐positive cells was greatest in fetuses aged about 12 or 13 days, reaching nearly 50%, but decreased gradually toward the neonatal period. The findings of this study suggest that, after the migration of neural crest cells, marked cell proliferation in the meninx begins. Differentiation into various layers then follows and is almost complete before birth, whereas the proliferation of arachnoid cells continues even in the early neonatal period.
Vascular invasion of the epithyseal growth plate: Analysis of metaphyseal capillary ultrastructure and growth dynamics
Authors: Hunter William L. , Arsenault A. Larry 
Published: February 2005

AbstractMetaphyseal blood vessels which invade the calcifying epiphyseal growth plate were examined by a variety of techniques to determine their morphology, cell division, and growth patterns as they relate to endochondral ossification. Four regions of these vessels were characterized: 1) sprout tips—the terminal ends of the capillary sprouts which impinge upon the hypertrophic chondrocytes of the growth plate; 2) region of extended calcified cartilage—those deeper vessels within the metaphysis which are surrounded by an extracellular matrix predominantly composed of extended septa of calcified cartilage; 3) region of bone deposition—further still from the epiphysis these microvessels are contained within a network of active bone deposition laid upon a scaffold of calcified cartilage; 4) region of primary vessels—at a distance of 350–500 μm from the epiphysis are dilated vessels with one or two layers of smooth muscle in their walls, which supply and drain the metaphyseal capillary plexus. The sprout tips are continuous blind‐ended vessels lined with an attenuated endothelium with no underlying basement membrane. Dividing endothelial cells are most frequently found in the region of bone deposition 175–200 μm behind the apices of the growing sprout tips. A time‐coursed, autoradiographic examination of cytokinesis revealed radio‐labelled endothelial cells to appear at the epiphysis after a 24 hr period. The metaphyseal capillary sprouts represent a continuous, unidirectional angiogenic vascular network which grows by elongation from the region of bone deposition; this region remians a fixed distance behind the sprout tips. These findings are discussed in light of the growth dynamics between this vascular plexus and the epiphyseal growth plate.
Dynamics of neuroepithelial body (NEB) formation in developing hamster lung: Light microscopic autoradiography after 3H‐thymidine labeling in vivo
Authors: Hoyt Richard F. , McNelly Nancy A. , Sorokin Sergei P. 
Published: February 2005

AbstractAutoradiographs were prepared from lungs of a newborn Syrian golden hamster exposed continuously to 3H‐thymidine for the final 4.5 days of a normal 16 day gestation. Silver grain were counted over nuclei of 1,298 smallgranule endocrine cells in 165 neuroepithelial bodies (NEBs) in the right upper lobe and along the left axial bronchus, where nodal NEBs occured at branch points and internodal NEBs in the airway between them. Nuclei of 1,005 nonendocrine airway epithelial cells were counted next to the NEBs. Label was distributed differently in the two populations: All nonendocrine cells were labeled, whereas many endocrine cells were not. In NEBs of the right upper lobe, total label (net grains/nuclear profile) averaged only 23% of that in nonendocrine cells. Along the left axial bronchus, mean label in nonendocrine cells and internodal NEBs rose 10‐fold between the hilum and the periphery. Increase for both populations were linear and parallel, but total label in the NEBs was consistently lower than that in the surrounding epithelium by 15 grains/nuclear profile. Nodal NEBs were more lightly labeled than those of the internodes, consistent with their earlier formation. A few very heavily labeled small‐granule cells (0.9%) occurred singly in the periphery of large, otherwise lightly labled NEBs. Statistically these belonged to the labeling distribution of nearby nonendocrine cells. In contrast to NEBs, neurons in 10 bronchial ganglia of the right lung were virtually unlabeled. These aris from vagal neural crest and seem to comprise an entirely distinct population. We conclude that NEBs belong intrinsically to pulmonary endoderm, not neural crest. During fetal life each develops from a cell or cells programmed to stop dividing well ahead of other elements in the epithelium. Their formation is linked closely to early proliferation of the bronchial tree and is an integral part of growth and differentiation of the airway lining. After a wave of initial formation has passed down the airway, small‐granule cells are added slowly to mature NEBs, probably through diffierentiation from adjoining airway epithelial cells—a potential mechanism for cell replacement in adult life.
Effects of tooth function on adjacent alveolar bone and Sharpey's fibers of the rat periodontium
Authors: Short E. , Johnson R. B. 
Published: February 2005

AbstractThere is little information about the effects of short‐term non‐, hypo‐, and hyperfunction of teeth on the (1) mineralization patterns of intrinsic and extrinsic (Sharpey's) fibers and (2) mean number and diameter of Sharpey's fibers of adjacent alveolar bone. The mineral density of intrinsic and Sharpey's fibers and the size and number of Sharpey's fibers could indicate the relative strength of the attachment of a tooth to bone in various functional situations. In the present study, non‐ and hypofunctional situations were created by selective extraction of right molar teeth of the rat; the contralateral teeth were placed in hyperfunction by the surgery. In non‐ and hypofunctionals, intrinsic and Sharpey's fibers of the crestal third of the alveolus were less densely mineralized than in hyperfunctionals or untreated controls. Mean Sharpey's fiber diameters were significantly greater and their mean number/unit area significantly less in non‐ than in hypo‐ or hyperfunctionals or untreated controls (P < 0.001). Mean Sharpey's fiber diameters in hyperfunctionals were significantly less than in untreated controls (P < 0.05). Hypofunction ameliorated the effects of nonfunction on mean diameter and number of Sharpey's fibers, but had little effect on the density of mineralization of either the intrinsic or Sharpey's fibers of the alveolus, suggesting that their mineralization may be controlled by factors other than occlusal forces from the adjacent teeth. Thus changes in the stress/strain environment within the periodontium, coincident to altered occlusal function of the adjacent teeth, rapidly affects the morphology of intrinsic and Sharpey's fibers of alveolar bone and ensures that adequate tooth support is maintained in the new functional situation.
Three‐dimensional computer‐aided analysis of the intraganglionic topography of primary muscle afferent neurons in the rat
Authors: Peyronnard Jean‐Marie , Messier Jean‐Pierre , Dubreuil Martin , Charron Louise , Lebel France 
Published: February 2005

AbstractA microcomputer system was used to reconstruct, in the L5 dorsal root ganglion (DRG) of the rat, the three‐dimensional arrangement of primary neurons which had been labelled by application of horseradish peroxidase (HRP) and fluoro‐gold (FG) to various muscle nerves of the leg. Analysis of the data and animation of the reconstructed images with commercially available software were instrumental in identifying the preferential intraganglionic locations of the neurons innervating muscles such as the soleus (SOL), the gastrocnemius lateralis (GL), and medialis (GM), or parts of the GM. These locations appeared to be somewhat related to the position of the muscles in the posterior compartment of the leg. Additionally, the study provided quantitative estimates of muscle afferent neuronal populations, allowed a comparison of the labelling performances of HRP and FG, and finally indicated that few DRG neurons project to two different muscles.
Immunocytochemical localization of proteins utilized in the formation of outer dense fibers and fibrous sheath in rat spermatids: An electron microscope study
Authors: Clermont Y. , Oko R. , Hermo L. 
Published: February 2005

AbstractAffinity purified antibodies prepared against proteins isolated from fibrous sheath (FS) and outer dense fibers (ODF) were utilized in an immunocytochemical study of spermatids at various steps of spermiogenesis. This study, using the immunogold technique, was performed on sections of Epon or Lowicryl embedded tissues examined with the electron microscope. In the case of FS antibodies there was a selective immunoreactivity of the FS itself from step 10 onwards, but no reactivity over the plasma membrane associated FS anlagen. In addition there was a diffuse immunoreaction over the cytoplasmic matrix from step 9 until step 18 of spermiogenesis but no reactivity over the various types of dense bodies (e.g., granulated bodies, reticulated body, etc.) seen in the cytoplasm of these spermatids. In the case of ODF antibodies the ODF were immunolabeled throughout their development from step 11 onward. In addition to a diffuse immunoreactivity of the cytoplasmic matrix of spermatids from step 9 until step 18 of spermiogenesis, there was an immunolabeling of “granulated bodies.” These bodies appeared in relation to ER cisternae during steps 10–14, increased in number and size during steps 15–17 and decreased in number thereafter leaving only a few coarsely granulated bodies in the residual cytoplasm which detached from late step 19 spermatids. No other cytoplasmic structures were labeled with the ODF antibody‐gold complexes. Thus the granulated bodies appeared to serve as a transitory storage site for some proteins destined to form ODF, a major cytoskeletal element of the tail of rat spermatozoa.
Development of the giraffe horn and its blood supply
Authors: Ganey Tim , Ogden John , Olsen John 
Published: February 2005

AbstractThe giraffe horn is an unusual cranial exostosis that lacks clear delineation and categorization as either horn or antler. The distinction between the two is made by contrasting their methods of development and basic composition. This process of development has not been detailed in the giraffe, a factor contributing to the difficulty in distinguishing the classification of these horns. In a chronological series of giraffe horns from prenatal and postnatal animals, we have observed unique morphologies that define their proper location on the skull, the blood supply to them, and the transitions involved in their histological development. While our observations have facilitated the classification of the giraffe horn, our interpretations were not always in accord with previous reports.
Comparison of mesenteric with antimesenteric crypt and villus populations in the mouse jejunal epithelium
Authors: Cheng Hazel , Bjerknes Matthew , Totafurno John 
Published: February 2005

AbstractVariation in the size and composition of crypts and villi along the length of the intestinal tract is well known. Here we investigate possible variation around the circumference of the intestine. This is a concern because most studies have ignored potential circumferential variation and its implications for experimental design in cell kinetic studies. We compared the crypt and villus populations of the mesenteric half with those of the antimesenteric half of proximal mouse jejunum. The branching crypt index and crypt and villus dimensions were measured. We found no evidence of differences in the branching crypt index, in the mean crypt and villus size, nor in the distribution of crypt and villus sizes between these two populations.
A novel mechanism of capillary growth in the rat pulmonary microcirculation
Authors: Burri Peter H. , Tarek Mojmir R. 
Published: February 2005

AbstractPostnatally, the rat lung parenchyma undergoes impressive growth. Within four months of birth, lung volume and alveolar and capillary surface areas increase over 20‐fold and capillary volume 35‐fold. Investigation of methacrylate casts of the pulmonary microvasculature revealed that, with age, lung capillaries were not only growing in surface and volume but also increasing their network density. We proposed that the capillary bed grows by formation of slender intravascular tissue pillars and termed this type of growth intussusceptive microvascular growth (Caduff et al., Anat. Rec., 216:154–164, 1986). The aim of this investigation was to detect the presence and to analyze the ultrastructure of slender tissue posts (diameter 1–2.5 μm) extending across the capillary lumina in serial electron microscopic sections of rat lung parenchyma (age 44 days). Computer‐assisted three‐dimensional reconstruction of the capillary lumen confirmed that tissue posts were matching the holes previously observed in casts. Post ultrastructure varied with size from a simple area of interendothelial contact to tissue pillars with a core of interstitial tissue. Based on the changing morphology of the pillars, a hypothesis for their development can be proposed: phase I, creation of a zone of contact between opposite capillary walls (formation of an interendothelial bridge); phase II, reorganization of the intercellular junctions of the endothelium, with central perforation of the capillary layer; phase III, formation of an interstitial post core, with successive invasion by cytoplasmic extensions of myofibro‐blasts, pericytes, and finally interstitial fibers; and phase IV, growth of the slender pillar to a normal full size capillary mesh. These findings support the new concept of intussusceptive growth of the lung capillary system.
Influence of epithelial‐mesenchymal interaction on the viability of facial mesenchyme II: Synthesis of basement‐membrance components during tissue recombination
Authors: Xu Zenglu , Parker Susan B. , Minkoff Robert 
Published: February 2005

AbstractThe presence of basement‐membrane components during tissue separation procedures was determined employing monoclonal antibodies to laminin and type IV collagen. In addition, the reconstitution of basement‐membrane components and the formation of the basement‐membrane were examined is isolated epithelium and mesenchyme and in tissue recombination. Epithelium and mesenchyme of maxillary precesses of chick embryos were seprated by a variety of protocols, including those employed in a prior study (Saber et al: Anat. Rec. 225:56–66, 1989). Results indicated that the protocol previously employed did not remove basement‐membrane components after enzymatic tissue separation. A revised protocol in which the basement‐membrane components (i.e., laminin and type IV collagen) were removed from isolated tissues prior to recombination revealed that a developmetal compartment and a gradient of cell viability, comparable in size and dimensions to that observed in the study of Saber et al. (ibid.) was present in the mesenchyme of recombined explants. Type IV collagen and laminin, therefore, do not appear to be required initially during tissue recombination in order for subsequent growth‐sustaining effects to be expressed. Additional studies revealed, however, that synthesis of basement‐membrane components occurred not only in isolated tissues but was altered markedly by tissue recombination. Culture of isolated tissues demonstrated induction of laminin synthesis in separated epithelium by 24 hours and induction of collagen synthesis in isolated mesenchyme by 24 hours. Recombination of epithelium and mesenchyme, however, resulted in rapid induction of laminin synthesis within 1 hour. Recombination of epithelium and mesenchyme after 24 hours resulted in the presence of laminin not only in epithelium but in mesenchyme as well. Both tissues were required for basement‐membrane formation which appeared to be fully reconstituted by 24 hours in culture. These observations indicate that recombination in culture alters the pattern of synthetic activity of these basement‐membrane components. These can be characterized as “early” (temporal) and “late” (spatial) responses by the recombined tissues.
Expression and ultrastructural immunolocalization of a major 66 kDa phosphoprotein synthesized by chicken osteoblasts during mineralization in vitro
Authors: Gerstenfeld L. C. , Gotoh Y. , McKee M. D. , Nanci A. , Landis W. J. , Glimcher M. J. 
Published: February 2005

AbstractEmbryonic chicken osteoblasts cultured over a 30 day period were used as a model system for studying the expression of bone phosphoproteins during cellular differentiation and the possible role of these proteins in extracellular matrix mineralization. Accumulation of total phosphoprotein in the cultures, as determined by O‐phosphoserine (Ser‐P) and O‐phosphothreonine (Thr‐P) amino acid analysis, revealed a > 10‐fold increase over the 30 day period. Total phosphoprotein synthesis, as assessed by (32P)‐, (3H)‐Ser‐P, and (14C)‐Thr‐P protein labeling, showed the highest levels concurrent with initial mineral deposition within the matrix. The major phosphoprotein present in chicken bones and synthesized by the cultured osteoblasts had a molecular weight of ∼66 kDa. This 66 kDa bone phosphoprotein (66 kDa BPP) was purified to homogeneity and was used for antibody production. Application of this antibody in Western blot analysis revealed that 66 kDa BPP was present only in protein extracts of mineralizing cultured osteoblasts and was absent in cultures of non‐mineralizing chondrocytes, myoblasts, and tendon fibroblasts. The 66 kDa BPP in vitro accumulated continuously in the extracellular matrix in a manner that paralleled both phosphoprotein synthesis and total phospho‐amino acid production. A comparison of the results obtained in vitro to those from developing embryonic tibiae in vivo demonstrated a similar qualitative and temporal expression of phosphoprotein and a continual accumulation of 66 kDa BPP in the matrix with advancing mineralization and developmental age. Ultrastructural immunocytochemistry using the 66 kDa BPP antibody and the protein A–gold technique revealed specific immunolabeling over electron‐dense regions of mineralization in the cultures that appeared identical to the distribution of labeling observed in vivo (McKee et al.: Connect. Tissue Res., 21:21–29, 1989; Anat. Rec. 228:77–92, 1990). These results demonstrate that this major 66 kDa BPP was expressed concurrently with other differentiated osteoblast functions and suggests that it may play a role in the initiation or regulation of mineralization.
Changes in glycoconjugates revealed by lectin staining in the developing airways of Syrian golden hamsters
Authors: Ito Takaaki , Newkirk Carnell , Strum Judy M. , McDowell Elizabeth M. 
Published: February 2005

AbstractLectin binding was studied in the developing airways of Syrian golden hamsters on gestational days 11–16 (day 16 is the day of birth). The trachea and lungs were fixed in 4% formaldehyde‐1% glutaraldehyde, 6% mercuric chloride‐1% sodium acetate‐0.1% glutaraldehyde, and 95% ethanol; embedded in paraffin; and stained with eight lectin‐horseradish peroxidase conjugates: Triticum vulgare (WGA), Dolichos biflorus (DBA), Helix pomatia (HPA), Maclura pomifera (MPA), Griffonia simplicifolia I‐B4 (GSA I‐B4), Arachis hypogaea (PNA), Ulex europeus I (UEA I), and Limulus polyphemus (LPA). Each lectin yielded a characteristic staining pattern, which modulated throughout development. In general, changes in staining characteristics of the tracheal epithelium preceded similar changes in the lobar bronchus, bronchiole, and alveolus. In the case of UEA I, MPA, WGA, and HPA, staining increased with time uniformly over the luminal surface of all epithelial cells. However, in the case of PNA, GSA I‐B4, and LPA, after the differentiation of ciliated and secretory cells, the apical surfaces of the ciliated cells stained more intensely than the apical surfaces of the secretory cells. Neuraminidase pretreatment enhanced PNA and GSA I‐B4 staining in both cell types. In the case of PNA, these light microscopic observations were confirmed by ultrastructural study. Unlike the other lectins, the pattern of staining with DBA was unusual. Staining was moderate at first, then decreased (days 13 and 14), then increased at all airway levels. This study shows that different glycoconjugates modulate in airway epithelial cells throughout fetal development.
Estimating anatomical–functional position coordinates in liver tissue
Authors: Barberá‐Guillem E. , Alonso‐Varona A. , Boyano M. D. , Vidal‐Vanaclocha F. 
Published: February 2005

AbstractHepatocyte enzyme activity was demonstrated by examining adult C57BL/6 mouse liver cryostat sections under a succinate dehydrogenase (SDH) histochemical reaction, and quantified by microspectrophotometry and microdensitometry. The hepatocyte SDH activity gradient along the path between the portal veins (PV) and efferent terminal hepatic venules (THV) was analyzed by measuring the concentration of the chromophore precipitated in 10 consecutive hepatic parenchymal domains located along imaginary lines drawn across the entire PV‐to‐THV distance. The profiles of intensity or of normalized relative optical density obtained on a high number of lines were correlated with distance values along the PV‐to‐THV pathway, enabling us to establish a general mathematical function relating SDH activity (chromophore concentration) to position values on a scale of 0 to 10 corresponding to the theoretical PV‐to‐THV distance. The equation can be used to interpolate the SDH activity surrounding any intrahepatic object located between the PV and the THV, thus making it possible to calculate the object's anatomical–functional position coordinates in the liver acinus. To demonstrate how this method is used, we have calibrated the intrahepatic position of hemopoietic foci induced in the liver tissue of adult mice treated with phenylhydrazine (PHZ), and show that these foci are located on coordinate 3.31 (maximum range 1.25–4.86) of the sinusoidal domain–that is, on the borderline between Rappaport's acinar zones 1 and 2.