bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bone healing after amputation of mouse digits and newt limbs: Implications for induced regeneration in mammals
Authors: Neufeld Daniel A. 
Published: February 2005

AbstractPostamputational healing was compared in nonregenerating and regenerating animals to determine whether bone healing might interfere with a regenerative response in mice. More than 150 mouse toes and 100 newt limbs were examined at the light microscope level. Stages of normal bone healing with approximate times of occurrence were established. Major differences in healing of these two species were seen. The periosteum produced hyaline cartilage, woven bone, and chondroid bone in mice, but only hyaline cartilage in newts. The endosteum produced woven bone in mice but no new growth in newts. Dead bone persisted in mice but was removed in newts. The marrow cavity became sealed in mice but remained open in newts. Despite these differences both animals produced skeletal tissue distal to the amputation plane. Woven bone formed distal to the amputation plane of mice. Cartilage formed distal to the amputation plane of newts, but cartilage was never seen distal to the plane of mice. Results of previous studies reveal that cartilage can be formed distal to the amputation plane of experimentally treated mice. Thus, although it does not regenerate, mouse bone is capable of producing, distal to the amputation plane, the type of skeletal tissue which appears at that location during an epimorphic regenerative response. This observation, in combination with other experimental results, indicates that both skeletal and soft tissues at the amputation site of treated mammals can resemble comparable tissues of newt limbs at an early stage of regeneration.
The narrowing of high endothelial venules of the rat lymph node
Authors: Bélisle C. , Sainte‐Marie G. 
Published: February 2005

AbstractThe lymph node contains blood vessels of a special type, termed “high endothelial venules” (HEVs), which are involved in the process of lymphocyte recirculation. In standard tissue sections, many HEVs exhibit a nearly closed or closed lumen containing small lymphocytes but few, if any, erythrocytes. The question arose as to whether the appearance of HEVs in tissue sections is influenced by the routine method of animal sacrifice and/or of tissue processing. Therefore, the present work investigated the effects on HEVs of sacrificing rats as well as of excising and fixing their nodes with various procedures. It was observed that procedures involving animal bleeding or blood loss from nodes increase the percentage of HEVs exhibiting a nearly closed or closed lumen. The results further revealed that the endothelial thickness and other morphological features of HEVs are modified by this artifactual narrowing of HEVs. The possible significance of the phenomenon is discussed.
Occurrence of bone fractures and parathyroid hyperplasia in paraphysectomized frogs (Rana catesbeiana)
Authors: Nelson Stanley R. , Foltz Floyd M. , Camarata Paul , Sarras Michael P. 
Published: February 2005

AbstractThe physiological role of the amphibian paraphysis was studied by removing the paraphysis from bullfrog tadpoles (Rana catesbeiana) and observing change in frog weight, bone development, and parathyroid glands 22 months later. Development was similar in control and paraphysectomized frogs until 6 months when the experimental frogs began to show greater weight gain which persisted for the remaining 16 months. At the time of sacrifice (22 months after paraphysectomy), the parathyroid glands of the experimental frogs were enlarged with a tenfold increase in wet weight and a sevenfold increase in dry weight. The glands from experimental frogs had numerous cysts filled with eosinophilic staining material; histologically the cell nuclei were rounded and the cytoplasm was vesiculated. At the time of sacrifice the experimental frogs had knoblike deformities along the shafts of the long bones. These deformities were due to callus formation around spontaneous bone fractures as revealed by X‐rays of the tibia‐fibulas and femurs. The dry weight was greater but calcium content less in femurs from experimental frogs. These findings indicate the paraphysis plays a role in calcium metabolism, possibly by producing a factor necessary for calcium action on cells.
Heterogeneous distribution of glycoconjugates in human kidney tubules
Authors: Hennigar Randolph A. , Schulte Bradley A. , Spicer Samuel S. 
Published: February 2005

AbstractParafin sections of normal human kidney were stained with a battery of ten lectin‐horseradish peroxidase conjugates. Staining of proximal tubules revealed a relatively uniform distribution of glycoconjugates having bi‐ and/or triantennary N‐linked sugar chains as well as terminal β‐galactose and α‐fucose in all cells. In contrast, terminal α‐ and β‐galactose and α‐fucose were localized in only some cells of the thin limbs, whereas N‐linked sugar chains and terminal α‐N‐acetylgalactosamine occurred in all cells. In the ascending thick limbs, terminal α‐N‐acetylgalactosamine was found in some cells and N‐linked sugar chains and terminal β‐galactose were present in all cells. The distal convoluted tubules contained N‐linked oligosaccharides and terminal β‐galactose in all cells. Terminal α‐N‐acetylgalactosamine was found in some but not all profiles of distal convoluted tubules in a few kidneys. In the initial (connecting) segment of cortical collecting ducts, cells varied in their content of glycogen and glycoconjugates with terminal α‐and β‐galactose, α‐fucose and α‐N‐acetylgalactosamine, but cells in this segment evidenced uniform localization of N‐linked sugar chains. A similar distribution of sugars occurred in the medullary ray segment of cortical collecting ducts, except for terminal β‐galactose which was present in all cells. In the medullary collecting ducts, there was also considerable cell‐to‐cell variation in the content and distribution of glycogen and glycoconjugates having N‐linked sugar chains, terminal α‐galactose, α‐fucose, α‐N‐acetylgalactosamine, and the disaccharide galactose‐(β 1 → 3)‐N‐acetylgalactosamine. The content and distribution of glycoconjugates in the nephron varied only slightly between kidneys from different individuals, but individual variability was extensive in the collecting ducts. The reasons for these individual differences have not been determined, however. Cellular heterogeneity of glycosubstances within the different regions of the human kidney correlates with similar findings in other mammals and implies diverse functional roles for the various types of complex carbohydrates in the kidney.
An exceptionally high density of muscle spindles in a slow‐tonic pigeon muscle
Authors: Rosser Benjamin W. C. , George John C. 
Published: February 2005

AbstractHistochemical and histological observations on the tiny wing muscle, M. coracotriceps, of the pigeon revealed a remarkably high density of muscle spindles (14,582 ± 2,302/g of muscle) – approximately 15 times the highest densities hitherto reported for any muscle. Furthermore, all of the extrafusal fibers of this muscle were of the slow‐tonic variety. This unique muscle probably functions as a mechanoreceptor extremely sensitive to changes in its own length.
Blood supply of the caudal mediastinal lymph node in sheep
Authors: Albertine Kurt H. , Wiener‐Kronish Jeanine P. , Staub Norman C. 
Published: February 2005

AbstractWe investigated the arterial supply to, and the venous drainage from, the caudal mediastinal lymph node (CMN) in 18 anesthetized and exsanguinated sheep. The purpose of this gross anatomic investigation was to determine the CMN's blood supply so that a structural base can be used to interpret studies of the bronchial circulation's role in the pathogenesis of pulmonary edema. In ten sheep, we cannulated the bronchoesophageal artery at its origin from the aorta and injected Microfil. This artery, which branches into cranial and caudal divisions 2–4 mm distal to its origin, supplied the esophagus, trachea, bronchi, and visceral pleura. The CMN is supplied by the caudal division, as it courses between the CMN and aorta. Microfil injected through the thoracic aorta did not enter the CMN when the bronchoesophageal artery was ligated at its origin. These results indicate that only the bronchoesophageal artery supplies the CMN. In eight sheep we cannulated the vein at the head of the CMN (dorsal mediastinal vein) and injected Microfil, both peripherally and centrally. Peripherally, injected veins reached the CMN and esophagus. The dorsal mediastinal vein extended posteriorly to the CMN in three of the eight sheep, eventually emptying into the left azygos vein near the diaphragm. Centrally, the dorsal mediastinal vein joined the left azygos vein near the heart in six of the eight sheep, including the three in which the dorsal mediastinal vein extended posteriorly to the CMN. In the remaining two sheep the dorsal mediastinal vein drained centrally into the right azygos vein. We conclude that the bronchoesophageal artery supplies the CMN and that either the left or right azygos vein drains it.
Three‐dimensional reconstruction of a small‐granule paracrine cell cluster in an adult hamster bronchus
Authors: Pearsall Allan Dorland , Hoyt Richard Francis , Sorokin Sergei Pitirimovitch 
Published: February 2005

AbstractAmine precursor uptake and decarboxylation (APUD) small‐granule cells were stained by periodic acid‐Schiff (PAS)‐lead hematoxylin in 0.5‐μm etched Epon sections of adult hamster lung fixed for transmission electron microscopy. The leading edge of a small‐granule cell cluster was identified in a segmental bronchus as a single PAS‐positive cell. From 256 serial thin sections through its entirety, a three‐dimensional wooden reconstruction of the cluster and morphometric estimates of the apical and basal surfaces, cell volume, and intracytoplasmic distribution of mitochondria and small granules was made. Of moderate size, the body consisted of 16 small‐granule cells, 11 forming its ovoid core with five outlying cells diverging at the margin; these were pyramidal, possessing wide bases and thin apical processes. At the bronchial surface, processes from the 11‐cell core emerged together, whereas the divergent cells emerged in groups of two and three. Ten Clara‐like cells and one ciliated cell encircled the core Altogether they formed a pseudostratified epithelium in contrast to the surrounding simple columnar epithelium. Deeper in the cluster, numerous cytoplasmic extensions interdigitated with those from adjacent cells, and toward the base the Clara‐like and APUD cells were increasingly interposed. In marked contrast to the apical cytoplasm, the infranuclear cytoplasm of the latter was densely packed with ca. 1,000 Å electron‐dense granules; and the basal, presumptively secretory face of each cell was five to six times greater than the area exposed to the bronchial lumen. Judged by granule size and ultrastructure, only one APUD cell type was recognized in the reconstructed cluster. Beneath it many fibrocytic processes were separated from the APUD cells by only the thickness of the basal lamina. Two fascicles of smooth muscle approached the cluster within 0.4–0.8 μm. Unmyelinated nerve fibers came as close but contacted only the muscle. Capillaries, in contrast, came no closer than 15 μm from the base of the body. Evidently, (1) fibrocytes and smooth muscle are more likely targets for secretions from such a paracrine body than cells reached through the bloodstream, and (2) not all small‐granule cell clusters are innervated.
Histological analysis of limb regeneration in postmetamorphic adult Ambystoma
Authors: Young Henry E. , Bailey Claudia F. , Markwald Roger R. , Dalley Bernell K. 
Published: February 2005

AbstractPrevious investigation into the regenerative ability of postmetamorphic adult land phase Ambystoma has revealed that (1) these species have the capacity to completely regenerate a limb, given optimal environmental conditions, and (2) the gross morphological characteristics of limb regeneration in these species compared favorably with the external regeneration morphology of aquatic phase forms. The present study concerns a histological and histochemical examination of the regenerating limb tissues and their respective extracellular and intracellular tissue matrices.Postmetamorphic adult Ambystoma were amputated through the forearm, placed within optimal environmental conditions, and allowed to regenerate. The tissues were harvested at designated intervals after amputation and prepared for light microscopic examination. The limb tissues were assayed histologically for similarities to and differences from previously established regeneration morphologies. It was noted that specific correlations (i.e., apical epidermal cap formation, bud outgrowth and elongation, palette formation, and digit formation) existed between regeneration histologies in these species and those previously reported for the aquatic urodeles, newt, axolotl, and larval salamander. By utilizing the histological and histochemical characteristics of the tissue, the regenerate limb was divided into five tissue units: epidermal, blastemal, soft, hard, and neuro/vascular. Based on the unique morphology of their extracellular matrices and respective histochemical staining patterns, four distinct blastemal regions were delineated within the blastemal units: subregenerate epidermal blastema, soft‐tissue blastema, hard‐tissue blastema, and core blastema. Histochemically, changing patterns of highly sulfated, weakly sulfated, and carboxylated polysaccharides and glycosylated compounds were located within both the extra‐ and intracelluler stump and regenerate tissue matrices during regeneration. In addition, these patterns of intra‐ and extracellular macromolecular material correlated to previous reports of similar‐type compounds assayed during regeneration in aquatic urodeles. With this in mind, the adult land phase Ambystoma can be considered an appropriate model system for studies concerning normal limb regeneration.
Computer‐aided reconstructive morphology of the baboon abducens nucleus
Authors: Augustine James R. , Huntsberger Terrance , Moore Michael 
Published: February 2005

AbstractOur previous effort at reconstructive morphology included the marriage of the horseradish perioxidase (HRP) neurohistochemical method to a Lucite plate reconstruction technique. Limitations imposed by this combination of methods has led us to develop a computer‐based system that utilizes image‐processing techniques and the data obtained from HRP processed serial light microscope sections. Labeled neurons of the baboon abducens nucleus were identified by HRP conjugated to wheat germ agglutinin. Using the resulting serial sections and a unique imaging process involving a pattern recognition algorithm, our computer‐based system automatically differentiates neuronal from nonneuronal features, delineates the surface boundaries of the neuronal population, and then assembles these serial sections into a solid three‐dimensional structure that can be rotated and further analyzed. A computer‐generated solid model of this neuronal population has been reconstructed and reproduced in a two‐dimensional publishable format. It is anticipated that with further development this system will be able to utilize data from the same specimen to study spatial relations through three‐dimensional reconstruction, as well as to study the quantitative morphology of a neuronal population. Other computer‐aided systems are noted, as are the advantages and shortcomings of the present method.
A morphometric analysis of the muscle‐tendon junction
Authors: Trotter J. A. , Hsi K. , Samora A. , Wofsy C. 
Published: February 2005

AbstractTransmission of the contractile force produced by skeletal muscle fibers from myofilaments to tendon fibers occurs at the muscle‐tendon junction. This interface between muscle and tendon is characterized by an amplification of the membrane area across which force is transmitted, with the result that stress at the muscle‐tendon interface is less than it would be if the muscle fiber ended without surface folding. The amount of stress reduction is proportional to the degree of surface amplification. Because an understanding of the mechanical properties of the muscle‐tendon junction requires a quantitative appreciation of the amplification of interfacial area, and hence the reduction of stress, produced by membrane elaboration at the muscle‐tendon junction, we have developed a reliable morphometric approach for quantifying this surface amplification. The approach reported here makes use of point‐counting techniques applied to thin sections of murine muscletendon junctions, together with a statistical analysis of the data. The results indicate that the load on the cell membrane at the muscle‐tendon junction is reduced approximately 1 order of magnitude by membrane amplification, compared to the load calculated to occur if the muscle fiber ended as a right cylinder. In addition, significant differences in the degree of membrane amplification have been detected among the four muscle‐tendon junctions analyzed in this study. These results and methods should prove useful in future analyses of normal and abnormal muscle‐tendon junctions.
Characterization of conotruncal malformations following ablation of “cardiac” neural crest
Authors: Kirby Margaret L. , Turnage Kirby L. , Hays Beth M. 
Published: February 2005

AbstractNeural crest cells from the cranial region of the neural fold populate the outflow tract of the developing chick heart. Removal of this region of premigratory neural crest has been shown previously to result in a high percentage of conotruncal malformations. The present study was undertaken to define more precisely the regions of premigratory neural crest which are needed for normal conotruncal development. Various regions and lengths of premigratory cranial neural crest were ablated using microcautery. Three defects in conotruncal development were significantly correlated with the neural crest ablation. These were high venticular septal defect, single outflow vessel originating from the right ventricle, and single outflow vessel overriding the ventricular septum.
The streaming submandibular gland
Authors: Zajicek G. , Yagil C. , Michaeli Y. 
Published: February 2005

AbstractTwenty female young adult rats were injected with tritiated thymidine (3HTdR). The animals were then killed in groups of five, at the following times: 1 hour, and 4, 16, and 23 days. Autoradiograms of sections through the submandibular gland were prepared, and the location of labelled cells in relationship to tubuli and acini was recorded. The different tubular and acinar cross sections could be distinguished by their cell number. Narrow tubuli had fewer nuclei than the wider ones. The nuclear number of a cross section was defined as its class and the location of a labelled epithelial cell was expressed in relationship to the class where it was found. The location of a labelled stromal cell was determined by the class of its neighboring tubular or acinar cross sections. The mean cell numbers of intercalated, granular, and striated duct cross sections were, respectively, 4.7, 10.5, and 10.2, while the average cell content of acini was 4.7 cells. One hour after labelling most labelled tubular epithelial and stromal cells were found in tubular cross sections (or low tubular classes), while in the acini, labelled epithelial and stromal cells were found mainly in wider cross sections (or higher acinar classes). Within the next 23 days labelled tubular cells and stroma proceeded into higher classes, while labelled acinar epithelium and stroma cells were displaced into narrower cross sections (or lower classes). The displaced tubular epithelium and stroma covered daily 0.26 classes. At this velocity the cell will reach the highest tubular class in 62 days and the estimated maximal tubular cell life span is 62 days. Acinar epithelium and stroma were displaced at a velocity of 0.024 classes/day, and their maximal life span was 125 days. These results indicate that contrary to the accepted belief, submandibular gland epithelium and stroma are renewing cell populations. Tubular cell progenitors are formed in the intercalated duct, from which they proceed into the granular. During this journey they are accompanied by dedicated stroma cells which are displaced at the same velocity as the epithelial cell. Moreover, the data suggest that the intercalated duct supplies also acinar cell progenitors which are displaced into the acinus. Since in the submandibular gland epithelium and stroma proceed along the tubuli and acini concurrently they probably carry their microenvironment with them.
Ultrastructural cytochemistry of carbohydrates in microfibrils associated with the amorphous elastin in the monkey aorta
Authors: Baba Tooru , Takagi Minoru , Yagasaki Hiroshi 
Published: February 2005

AbstractTwo distinct ultrastructural components of elastic fibers can be identified–namely, the amorphous elastin and the microfibrils. We have examined the tunica adventitia of monkey aortas to demonstrate differential localization of carbohydrates in elastic fibers and collagen fibrils using Thiéry's periodic acidthiocarbohydrazide‐silver proteinate (PA‐TCH‐SP) staining of thin sections for vicinal‐glycol‐containing complex carbohydrates, en bloc concanavalin A (Con A) staining specific for α‐D‐mannosyl and α‐D‐glucosyl groups, and en bloc wheat germ agglutinin (WGA) staining specific for N‐acetyl‐D‐glucosamine, N‐acetylneuraminic acid, and N‐acetyl‐D‐galactosamine. The PA‐TCH‐SP method moderately stained microfibrils and weakly stained collagen fibrils, but did not stain the amorphous elastin. Both Con A and WGA staining methods strongly stained microfibrils and moderately stained collagen fibrils, whereas the amorphous elastin lacked staining. Thus PA‐TCH‐SP, Con A, and WGA staining methods allow differential ultrastructural localization of carbohydrates in elastic fibers and collagen fibrils in monkey aortic adventitia and demonstrate the presence of more carbohydrate components in microfibrils than in collagen fibrils, whereas amorphous elastin lacks carbohydrate staining.
Ontogeny of small‐granule APUD cells in hamster lung: A morphological study
Authors: Sarikas Stephen N. , Hoyt Richard F. , Sorokin Sergei P. 
Published: February 2005

AbstractDevelopment of small‐granule APUD cells and cell clusters was studied in 13‐day to 15‐day fetal hamster lungs by periodic acid‐Schiff (PAS)‐lead hematoxylin staining, monoamine fluorescence, and transmission electron microscopy. We examined 11‐day and 12‐day fetal, early postnatal, and adult animals only by PAS‐lead hematoxylin. Precursors of small‐granule cells first appear as PAS‐negative clear cells in proximal airways of 13‐day lung, occurring singly or in clusters of 2–25 cells and standing out among their undifferentiated, glycogen‐laden, PAS‐positive neighbors. By 14 days, developing small‐granule cell clusters are prominent in main and lobar bronchi, extending 2–3 airway generations into the periphery. Clear‐cell clusters, similar to those seen in 13‐day lung, appear in peripheral airways and reach within one generation of developing terminal sacs. By 15 days, a few small, small‐granule cell clusters are located at bronchioloalveolar junctions. Comparatively mature clusters occur in proximal airways; they are characterized by specific formaldehyde‐induced monoamine fluorescence demonstrable after exposure in vitro to 5‐hydroxytryptophan. In early postnatal stages, PAS‐positive granules are resolvable toward the base of some endocrine cells. Ultrastructurally, pulmonary APUD cells contain numerous membrane‐limited granules (180‐nm diameter) of varying electron density. In 13‐day lung, granules sparsely populate the cytoplasm of clear cells, but as the cells mature, the granule population increases and becomes concentrated in the basal cytoplasm. Fetal development of smallgranule cells is therefore compressed into the last 4 days before birth. Most clusters appearing in neonatal lungs are not yet fully mature, and not all subtypes of this population are present until some time later.