bluuebunny/crossref_metadata_2025_split huggingface dataset:
Distribution and histochemical characterization of goblet cells in the nasal cavity of piglets
Authors: Larochelle Renée , Martineau‐Doizé Béatrice 
Published: February 2005

AbstractThe present study was desiged to compare the distribution of goblet cells and the histochemical composition of mucosubstances produced by these cells in the nasal cavity of piglets aged from 1 to 28 days. Serial transverse sections were stained to demonstrate neutral, acidic, and sulfated mucosubstances. Sections located at eight reference levels rostrocaudally in the nasal cavity and defined regions on these sections were used for goblet‐cell counting. There was a nonhomogeneous distribution of goblet cells in the nasal cavity of piglets. A rostrocaudal increase in goblet‐cell density was observed with the highest densities found in the ventral meatus and on the septum. There was no difference in this pattern of distribution according to age of the piglets. However, age‐related differences were observed in the prevalence of goblet cells containing sialomucins, sulfomucins, or both. While sialomucins were prevalent at 1 and 14 days, sulfomucins predominated in the rostral half of the cavity at 28 days. Our results indicate a maturation of the products of secretion with aging in piglets. The affinity of infectious agents for sialylated glycoconjugates and the predominance of sialomucins in the nasal cavity of newborn piglets could account for their greater susceptibility to bacterial infection.
The sinoatrial ring bundle: A cardiac neural communication system?
Authors: Roberts L. A. 
Published: February 2005

AbstractThe sinoatrial ring bundle (SARB). was originally described as a “whitish bundle of tissue which describes an almost complete loop around the two venae cavae and the coronary sinus” in the adult rabbit heart (Paes de Carvalho et al., 1959). The histologically and electrophysiologically differentiated structure, derived from the embryonic venous valves, was suitably placed for rapid conduction from sinoatrial (SA) to atrioventricular (AV) node, but no evidence was found for this role. Today, the function of the SARB remains obscure. Cholinesterase/silver staining reveals the neural pattern associated with the SARB and suggests a function. Throughout its extent, the SARB contains a bundle of parallel muscle fibers and accompanying long nerves. The nerves distribute to structures at either side of the loop: superolaterally to pectinate muscle and inferomedially to the region of the AV node. Along the curve of the right SARB, the nerves contribute to a dense neural plexus with nerves coiled around muscle. The plexus communicates with the nearby SA node and with the ganglia inferior to the node near the inferior vena cava. The morphological pattern of neural elements is suitably organized to suggest tension monitoring and internodal, neural communication.
Auditory epithelial migration. III. development of the stratified squamous epithelium of the tympanic membrane and external canal in the mouse
Authors: Michaels Leslie , Soucek Sava 
Published: February 2005

AbstractThe development of the stratified squamous epithelium of the tympanic membrane and external auditory canal was studied in serial sections of 124 mouse ears aged from 11 gestational days to 100 days. A fold developed from the edge of the fundus of the primary canal. It possessed two regions: firstly the meatal plate, which produced the pars tensa‐covering epithelium (zone 2) and most of the deep ear canal epithelium (zone 3), and secondly the fundal extension plate, which grew from that part of the fundus not forming the meatal plate. The fundal extension plate gave rise to the pars flaccida‐covering epithelium (zone 1) and also to the adjacent deep canal epithelium (zone 3). A difference from human development was that zone 3 in the mouse, in both the meatal plate‐and the fundal extension plate‐derived areas, formed adnexal structures. In the early development of the meatal plate, zone 3, at its tip, was swollen and actively mitotic and extended always for a short distance on to the zone 2 side. Zone 2, first perceived two days after zone 3, became progressively attenuated, and by the fourth day after its formation was a single thin layer. It is suggested that the proximal part of zone 3, situated in the mature ear around the periphery of the tympanic membrane, is a generation center for unidirectional outward flux of epithelium which terminates in the mouse at the first adnexal structure. It may cause the whole of zone 2 to move in the same direction by negative contact inhibition.
An immunohistochemical study of the GnRH neuron morphology and topography in the adult female rabbit hypothalamus
Authors: Foster Warren G. , Younglai Edward V. 
Published: February 2005

AbstractThe morphology and distribution of immunoreactive (GnRH) neural elements in the hypothalamus of the adult nulliparous female rabbit were examined. Approximately 1,000 GnRH cells (range 890‐1136) were counted in the right half of the hypothalamus. Two distinct GnRH cell types were observed: GnRH cells with rough or spiny contours accounted for 64% of the total immunoreactive cells, and smooth‐contoured cells represented 34% of the total. The majority of immunoreactive neural elements were found in the anterior hypothalamus. GnRH cells and processes were located primarily in the ventral and medial anterior hypothalamus forming an inverted V pattern. Processes were followed from the medial preoptic area and suprachiasmatic nucleus to the infundibular stem. Extrahypothalamic projections of GnRH cells were observed. Immunoreactive fibers were also found to contact the ependymal lining of the third ventricle. It is concluded that two morphologically distinct GnRH cell types exist and have a broad distribution in the rabbit hypothalamus. The functinal significance of these cell types requires further study.
Immunological mutants of the mouse
Authors: Shultz Leonard D. 
Published: February 2005

AbstractMutations at more than 30 loci in mice have been shown to cause deleterious effects on the immune system. Immunologic defects caused by certain of these mutations are determined at the level of hematopoietic progenitor cells or at the level of hematopoietic cell‐stromal cell interactions. The immunological mutants described in this paper serve as experimental tools with which to increase our understanding of the development and regulation of the mammalian immune system.
Sequence‐specific binding of a c‐myc nuclear‐matrix‐associated region shows increased nuclear matrix retention after leukemic cell (HL‐60) differentiation
Authors: Chou Robin H. , Churchill Judy Rae , Mapstone Diane E. , Flubacher Marcella M. 
Published: February 2005

AbstractHL‐60 cells, a human promyelocytic leukemia cell line, contain amplified c‐myc DNA sequences and mRNA transcripts. These cells can be induced to undergo macrophage differentiation by phorbol esters, which results in suppression of c‐myc expression and cessation of cell proliferation. The nuclear matrix (NM), a nuclear skeleton resistant to DNase I digestion and high salt extraction, is proposed to be involved in DNA replication, gene regulation, and the correct distribution of DNA at mitosis. We have previously identified a nuclear‐matrix‐associated region (MAR) of the c‐myc protooncogene to reside in a 1.4‐kb region between Cla I and Eco RI restriction sites at the 3′‐end of the gene. A 172‐bp Dra I/Dra I subfragment of the 1.4‐kb region was shown to be a major component of the MAR (myc‐MAE), and this subfragment was demonstrated to be recognized by a nuclear protein (p25). In this report we demonstrate that ϕX174 DNA, or the synthetic copolymers poly[d(G·C)] and poly[d(A·T)], are not effective suppressors of the binding of the myc‐MAR to isolated NM, indicating that the binding sequence(s) are unique. We find that the addition of partially purified protein p25 increases the relative affinity of the myc‐MAR for HL‐60 NM in an in vitro assay system. NM isolated from HL‐60 macrophages induced by phorbol esters retains significantly more myc‐MAR DNA fragment in the presence of an excess amount of competitor DNA than does NM from untreated HL‐60 cells. These data suggest that a change of the myc‐MAR association with the NM occurs after monocytic differentiation of HL‐60 cells.
Bone marrow‐thymus axis in senescence
Authors: McCormick Kevin R. , Haar Jack L. 
Published: February 2005

AbstractThis presentation offers a brief review of the bone marrow‐thymus axis in senescence, a putatitive model for thymocyte differentiation, and recent results of our work on the status of pre‐thymic stem cells in aged mice. The data presented here provide further evidence for a thymus endocrine influence on the bone marrow stem cells, specifically lymphocyte precursors. It has been pstulated that the thymic hormones may act on lymphocyte precursors in the bone marrow and that the loss of thymic factors during senescence may be a contributing factor to the decreased cellular immune function. This study used Haar's in vitro model to investigate the bone marrow‐thymus axis in aged mice. Erythroid‐depleted bone‐marrow cells from 3‐month‐ and 24‐month‐old CBA (Thy 1.2) mice were placed in the upper half of a blind‐well chamber with thymus supernatant in the lower half. Experimental cells were treated with thymus supernatant for 1 hr prior to migration. This study confirmed that pre‐thymic stem cells in aged bone marrow are deficient in their ability to migrate to the thymus supernatant. It also revealed that treatment of the old bone marrow with thymus supernatant, made from neonatal thymus cultures, could dramatically improve the thymus migrating ability of the aged bone‐marrow stem cells.
Ultrastructural and morphometric analysis of the separation of two thigh muscles in the chick
Authors: Schroeter Sally , Tosney Kathryn W. 
Published: February 2005

AbstractLimb muscles separate from one another in a complex but highly stereotyped sequence and spatial pattern. The process of separation is characterized by the progression of a region of increased extracellular space, the cleavage zone, along the proximodistal axis between the individual muscle anlagen. We analyzed ultrastructurally the muscles and cleavage zone during the separation of two representative muscles, the developing sartorius and iliotibialis in the chick thigh, to establish an accurate baseline for an analysis of the mechanisms of separation. Comparisons of the morphology and distribution of cells before and after separation show no evidence that muscles became separated by the massive influx of an exterior cell population; if populations invade the cleavage zone, they are small. We do find characteristic transitions within the cell population of the cleavage zone in situ that could accomplish cleavage without invoking massive cell movements. These progressive transitions within the cleavage zone include a loss of close cell‐cell interactions, an increase in extracellular space, the assumption of a more stellate morphology by mesenchyme cells, and a gradual alteration in the composition of the extracellular matrix from one typical of early muscle to one typical of loose connective tissue. Myotubes do differentiate between the incipient muscles, ruling out the possibility that the location where muscles will separate is defined by sites where myotubes fail to differentiate. Instead, the myotubes in the cleavage zone gradually diminish in number and appear to be specifically recognized and removed from the cleavage zone by phagocytes. We suggest that the transitions within the cleavage zone, including the loss of muscle cells, are a result of the progressive differentiation of loose connective tissue. If so, then the spatial pattern and process of cleavage is a consequence of spatially programmed cell differentiation.
Lumbar lateral motor columns and hindlimbs of two Xenopus laevis chromosome mosaics
Authors: Sperry David G. 
Published: February 2005

AbstractTwo chromosome mosaic Xenopus laevis, one tadpole and one metamorphic animal, both with different sizes of neurons on the left and right sides of their brains and spinal cords, have left and right lumbar lateral motor columns (L‐LMCs) of equal lengths but composed of strikingly different numbers of motoneurons (40% fewer motoneurons on the side composed of larger cells). One portion of the lumbar cord in the metamorphic animal is bilaterally symmetrical; the cells on both sides are small and the numbers of motoneurons per section are the same. The mosaics demonstrate that column length and motoneuron density (number per section) are, or can be, regulated bilaterally and that changing cell size affects factors controlling cell density but not column length. Except for the peripheral nerves, there is no evidence of any side‐to‐side differences in the hindlimb tissues. Whether the side‐to‐side difference in L‐LMC motoneuron number in the stage 66 mosaic corresponds to any feature of the hindlimbs is unknown, but similar side‐to‐side differences in an early and a late stage mosaic animal support the idea that whatever creates the initial number may also determine the final number of motoneurons.
New aspects of the morphology and function of the human hip joint ligaments
Authors: Fuss Franz K. , Bacher Andreas 
Published: February 2005

AbstractThe capsular ligaments of the human hip joint were submitted to exact morphological analysis, and they proved to be multiple and numerous. We have described various ligamentous systems and their interconnections, and have suggested new terminologies and systematics. The ligaments were subjected to functional analysis by means of measuring strips to determine the positions in which the ligaments are taut. The ligament systems were all found to serve a restrictive function, and various parts of the apparatus restricted all possible movements in the hip joint. Extension is restricted by the medial iliofemoral complex, abduction by the pubofemoral ligament, and adduction by the posterior coxal ligaments and by the superior ischiofemoral ligament. Flexion is restricted by the inferior ischiofemoral ligaments, inward rotation by the superior ischiofemoral ligament, and outward rotation by the lateral iliofemoral complex. Only the ligament of the femoral head is unable to exert a restricting function, despite reaching a state of tension in extreme adduction.
Electron microscopic and histochemical studies of the mononuclear osteoclast of the mouse
Authors: Domon Takanori , Wakita Minoru 
Published: February 2005

AbstractOsteoclasts collected from the long bones of mice were cultured on dentin slices. To identify osteoclasts, the tartrate‐resistant acid phosphatase (TRACPase) activity of cultured cells was histochemically examined by the azo dye method. The TRACPase‐positive cells could be distinguished from other cells by light microscopy. The cells were sectioned by alternating semithin and ultrathin sections to observe their ultrastructure and three‐dimensional structure.TRACPase activity was detected both in multinucleated osteoclasts and in mononuclear cells. Most of the mononuclear TRACPase‐positive cells had features similar to preosteoclasts. A mononuclear TRACPase‐positive cell was a ruffled border and clear zone was reconstructed three‐dimensionally by NIKON COSMOZONE 2SA. The reconstruction showed that this cell possessed a large clear zone and small ruffled border. Under the ruffled border, no lacuna was apparent; but there was disruption of the dentin surface. The results suggest that this cell was a mononuclear osteoclast and that it might have been in the process of making a new lacuna.
Morphological and histochemical comparison of the cells elicited by ectopic bone implants and tibial osteoclasts
Authors: Kelly Janet Dvonch , Schneider Gary B. 
Published: February 2005

AbstractPellets of mineralized and demineralized bone and a composite mixture of mineralized and demineralized, devitalized bone particles were implanted subcutaneously on the dorsal body wall of young adult rats. Two weeks post‐implantation, the pellets were removed and processed for histochemical and morphological analyses. Rat proximal tibia was also processed for evaluation. The levels of tartrate‐resistant acid phosphatase (TRAP) activity in the multinucleated giant cells (MNGCs) from each of the three implants and from osteoclasts were assessed using an image analyzer. The osteoclasts from the proximal tibia and the majority of MNGCs from the demineralized implants demonstrated high levels of TRAP activity. MNGCs from the mineralized implants showed either a low level or absence of TRAP activity. Most MNGCs from the composite implants exhibited a low level of TRAP activity; however, there was a population of cells that demonstrated a high level of reaction product, similar to that seen in the tibia and demineralized implant. Morphologically, osteoclasts from the proximal tibia and from the osteogenic demineralized implant exhibited ruffled borders. A small population of MNGCs from the composite implant also revealed osteoclastic features. In summary, MNGCs from the mineralized implant did not exhibit a level of TRAP reaction product or morphology similar to osteoclasts, while the majority of cells from the demineralized implant and a subpopulation of the MNGCs elicited by the composite implant did demonstrate TRAP expression and morphology similar to osteoclasts. The expression of osteoclastic characteristics in cells at an ectopic site may be dependent on accessory signals from the skeletal microenvironment; such signals appear to be absent from or incomplete in the mineralized implants but appear to be present when demineralized bone particles are implanted.
Genesis of hadacidin‐induced cleft palate in hamster: Morphogenesis, electron microscopy, and determination of DNA synthesis, cAMP, and enzyme acid phosphatase
Authors: Shah Ravindra M. , Schuing Ruth , Benkhaial Gheith , Young Alan V. , Burdett David 
Published: February 2005

AbstractA morphological, electron microscopic, and biochemical study was undertaken to analyze the genesis of hadacidin‐induced cleft palate in hamster fetuses. Gross and light microscopic observations indicated that hadacidin affected the growth of vertical palatal shelves to induce cleft palate. Electron microscopic observations showed that initial hadacidin‐induced changes were seen in the mesenchymal cells. Within 12 hr of drug administration, the perinuclear space was swollen and a lysosomal response injury was evident in the mesenchymal cells. Subsequently, 24 hr after hadacidin treatment, lysosomes appeared in the epithelial cells; changes were also seen in the basal lamina which included separation of the lamina densa from the basal cells, duplication of lamina densa, and complete loss of basal lamina. Between 36 and 42 hr post‐treatment, the cellular and basal lamina changes subsided, and the epithelium of vertical shelves underwent stratification. Biochemical determination of enzyme acid phosphatase indicated that the levels of enzyme activity in both the control and treated palatal tissues corresponded to the appearance of lysosomes. Measurement of cAMP levels suggested that the peak activity of cAMP corresponded to that of enzyme acid phosphatase and cell injury. The cAMP activity in hadacidin‐injured cells, however, was significantly lower in comparison to that of the dying cells of control palates. Hadacidin treatment also affected DNA synthesis in the developing primordia of the palate. It was suggested that hadacidin injures the precursor cells of the palate prior to the appearance of the primordia, and subsequently affects their proliferative behavior, stunting the vertical growth of the palatal shelves and inducing a cleft palate.
Ultrastructure of palatal taste buds in the perihatching chick
Authors: Ganchrow Donald , Ganchrow Judith R. , Goldstein Ronald S. 
Published: February 2005

AbstractPalatal taste buds of perihatching chicks were examined by electron microscopy. Four intragemmal cell types were characterized.(1) Light: with voluminous, electron‐lucent cytoplasm containing scattered free ribosomes, rough and smooth endoplasmic reticulum, plump mitochondria, sparse perinuclear filaments, occasional Golgi bodies, and numerous clear and dense‐cored vesicles. Clear vesicles sometimes aggregate in a presynaptic‐like configuration apposed to an axonal profile. These cells contained large, spherical, uniformly granular nuclei with one nucleolus. (2) Dark: with dense cytoplasm containing filamentous bundles surrounding the nucleus, occasional clear vesicles, centrioles, rough endoplasmic reticulum, and compact mitochrondria. The apical cytoplasm noticeably lacks dense secretory granules. Irregular to lobulated nuclei are densely granular, and contain scattered clumps of chromatin, adhering especially to the inner leaflet of the nuclear membrane, and at least one nucleolus. Cytoplasmic extensions of dark cells envelop other intragemmal cell types and nerve fibers. Light and dark cells project microvilli into the taste pore. (3) Intermediate: contain gradations of features of light and dark cells. (4) Basal: darker than the other intragemmal cell types and confined to the ventral bud region. Putative afferent synapses in relation to light cells, and axo‐axonal contacts are described. While the appearance of axo‐axonal contacts may be a transient developmental event, other bud features are consonant with observations in adult chickens and suggest that the peripheral gustatory apparatus is mature at hatching in this precocial avian species.
Temporospatial study of the migration and distribution of cardiac neural crest in quail‐chick chimeras
Authors: Miyagawa‐Tomita Sachiko , Waldo Karen , Tomita Hitoshi , Kirby Margaret L. 
Published: February 2005

AbstractIt has been demonstrated that the septation of the outflow tract of the heart is formed by the cardiac neural crest. Ablation of this region of the neural crest prior to its migration from the neural fold results in anomalies of the outflow and inflow tracts of the heart and the aortic arch arteries. The objective of this study was to examine the migration and distribution of these neural crest cells from the pharyngeal arches into the outflow region of the heart during avian embryonic development. Chimeras were constructed in which each region of the premigratory cardiac neural crest from quail embryos was implanted into the corresponding area in chick embryos. The transplantations were done unilaterally on each side and bilaterally. The quail‐chick chimeras were sacrificed between Hamburger‐Hamilton stages 18 and 25, and the pharyngeal region and outflow tract were examined in serial paraffin sections to determine the distribution pattern of quail cells at each stage. The neural crest cells derived from the presumptive arch 3 and 4 regions of the neuraxis occupied mainly pharyngeal arches 3 and 4 respectively, although minor populations could be seen in pharyngeal arches 2 and 6. The neural crest cells migrating from the presumptive arch 6 region were seen mainly in pharyngeal arch 6, but they also populated pharyngeal arches 3 and 4. Clusters of quail neural crest cells were found in the distal outflow tract at stage 23.