bluuebunny/crossref_metadata_2025_split huggingface dataset:
Ultra‐high‐resolution scanning electron microscopic studies on the membrane system of the parietal cells of the rat in the resting state and shortly after stimulation
Authors: Ogata Takuro , Yamasaki Yuichi 
Published: February 2005

AbstractThe three‐dimensional organization of the membrane system of the rat parietal cells in the resting state and during early stimulation with tetragastrin (gastrin) was determined by ultra‐high‐resolution scanning electron microscopy. Specimens were prepared by cytoplasmic matrix removal using the aldehyde‐osmium‐DMSO‐osmium procedure. The intracellular canaliculus was lined with numerous microvilli. Viewed from the cytoplasmic side, the intracellular canaliculi appeared as an arborized system of cactus‐like structures with numerous round holes about 100 nm in diameter corresponding to the basal openings of the microvilli. The intracellular canaliculi were more developed after gastrin stimulation than in the resting state. In resting cells, most of the tubulovesicles were isolated, 100–200 nm in diameter, spherical or tubular in shape, and had a smooth surface. After gastrin stimulation, these structures were interconnected by slender tubules of about 30 nm in diameter forming together tubulovesicular network. Occasionally, swollen and shrunken profiles were observed. The tubulovesicular network was connected with the intracellular canaliculus only at a few sites by the slender connecting tubules. Fusion of the tubulovesicular network with the intracellular canaliculus is observed at such sites. In the fasted rat, the microvilli were slender and their interior was packed with some kind of ill‐defined material, probably microfilaments. However, after gastrin stimulation, the microvilli were swollen and their interior was almost empty. These morphological changes seem to indicate the accumulation of fluid in the microvilli after gastrin stimulation, with subsequent swelling. © 1993 Wiley‐Liss Inc.
Endothelin‐1 localization in bone cells and vascular endothelial cells in rat bone marrow
Authors: Sasaki Takahisa , Hong Mei‐Hua 
Published: February 2005

AbstractEndothelin‐1 (ET‐1) localization in bone cells and associated vascular endothelial cells in metaphyseal bone marrow of the rat femur was examined by a biotin‐streptoavidin‐horseradish peroxidase method in paraffin sections and by indirect immunogold techniques in post‐embedded ultrathin sections. Mouse anti‐ET‐1 monoclonal antibody was used as the primary antibody. In metaphyseal bone marrow, intense immunostaining was observed over osteoclasts, osteoblasts, young osteocytes, and vascular endothelial cells. But bone and cartilage matrices and chondrocytes in the proliferating zone were negative for immunoreaction. At the subcellular level, specific immunogold labeling was localized along plasma membranes and in the cytoplasm including those of ruffled borders and clear zones of osteoclasts. Some colloidal gold particles were also detectable within pale vacuoles of osteoclasts. Immunoreactivity was also found along the plasma membranes, cisterns of rough‐surfaced endoplasmic reticulum, mitochondria, and cytoplasmic matrices of osteoblasts, but was less intense than that of osteoclasts. In endothelial cells of blood capillaries in close proximity to bone cells, intense immunolabeling occurred over the cytoplasm. None of the cases examined showed accumulation of immunogold particles in the secretion granules of these cells. © 1993 Wiley‐Liss, Inc.
Three‐dimensional cytoarchitecture of complex branched fibers in soleus muscle from mdx mutant mice
Authors: Tamaki Tetsuro , Sekine Tadashi , Akatsuka Akira , Uchiyama Shuichi , Nakano Shoichi 
Published: February 2005

AbstractThree‐dimensional cytoarchitecture and types and features of muscle fibers were examined in soleus muscles from mdx mutant mice at different stages of development. In the 2‐week‐old mice, no abnormal muscle fibers were observed light microscopically, whereas in the 4‐week‐old animals, disrupted fibers were frequent in light microscopy and scanning electron microscopy. Muscle fibers fused with several short fiber branches appeared at the sixth week after birth and increased in number until the tenth week. In the 1‐year‐old mice, approximately ten or more muscle fibers were seen fused together. They had many complex branches forming an “anastomosing syncytial reticulum.” Muscle fibers with irregular diameters and aggregations of the same type fibers were also observed.Our results demonstrated that these complex branched fibers might be formed by long term repetition of the degeneration and regeneration cycle during the development of soleus muscles, indicating that the characteristic features of muscle fibers with irregular diameters and aggregations of the same type fibers are certainly dependent on the existence of the complex branched fibers. © 1993 Wiley‐Liss, Inc.
Computer analysis of the human embryo growth curve: Differences between published ultrasound findings on living embryos in utero and data on fixed specimens
Authors: Dickey Richard P. , Gasser Raymond F. 
Published: February 2005

AbstractAccurate information on the normal growth rate of the human embryo is fundamental to a better understanding of the embryonic period of pregnancy. Crown‐rump length measured previously in utero (N = 227) with vaginal ultrasound in 107 in vitro fertilization (IVF) or gamete intrafallopian transfer (GIFT) singleton pregnancies was compared to the greatest length of fixed human embryos from the Carnegie collection, of known developmental stage whose postovulatory ages were estimated from menstrual histories. Average crown‐rump length in utero was 60% of the greatest length of the fixed specimens prior to postovulation day 33, but were equal after postovulation day 40. The growth rate of in utero embryos and fixed specimens, analyzed by computer using exponential equations, was compared to linear and polynomial equations used in previously published embryo growth tables. The exponential equation, length = exp(a + b/age), fit in utero measurements best, while the equation length = exp[a + b/exp(age)] fit the fixed specimens best. Differences between length in utero and in fixed specimens may be related to distortion of the fixed embryos resulting from the formalin fixation, to ultrasound distortion, to curling of the embryo, or to incorrectly estimated ages of the fixed specimens. Study of human embryos in utero is now practical with vaginal ultrasound. © 1993 Wiley‐Liss, Inc.
Role for differential cell proliferation in perforation and rupture of chick pharyngeal closing plates
Authors: Miller Sue Ann , Favale Alicia M. , Knohl Stephen J. 
Published: February 2005

AbstractPatterns of cell proliferation show two distinct domains around avian pharyngeal closing plates as they form, perforate, and rupture. Pouch endoderm and groove ectoderm are in one domain showing 81–86% proliferation, which suggests relatively rapid growth. Cells in epithelia that comprise the pharyngeal closing plates contiguous with pouch and groove epithelia are vital but are dividing at a significantly lower percentage (62–64%). This phenomenon is similar to the lag in growth reported for cells in the oral membrane around the time of rupture (Miller and Olcott, 1989: Anat. Rec., 223:204–208), is consistent with Waterman's suggestion (1985: Anat. Rec., 211:450–457) that cellular reorganization, rather than massive degeneration, is a major mechanism of initial perforation, and suggests that differential growth is a contributor to perforation and rupture of chick pharyngeal closing plates. © 1993 Wiley‐Liss, Inc.
Effect of soft diet and aging on rat masseter muscle and its motoneuron
Authors: Miyata Hirofumi , Sugiura Takao , Kawai Yosuke , Shigenaga Yoshio 
Published: February 2005

AbstractTo determine the effect of a soft diet and aging on the masticatory motor unit, we investigated the morphologic and metabolic properties of the superficial masseter muscle and its motoneurons in rats. Twenty rats were divided into four groups of five rats: rats fed a hard diet until 4 months after birth (hard, young), rats fed a soft diet until 4 months after birth (soft, young), rats fed a hard diet until 22 months after birth (hard, old), and rats fed a soft diet until 22 months after birth (soft, old). The diameter of the fast‐twitch oxidative glycolytic muscle fiber was significantly smaller in the soft than the hard, and in the old than the young groups. The glycolytic enzyme (phosphofructokinase) activity of the muscle was significantly weaker in the old than the young group. There was no significant difference in soma diameter of the motoneurons between the soft and hard group, while the diameter was significantly larger in the old than in the young group. There was no significant difference in NADH‐diaphorase activity of the motoneurons between the soft and hard group, while significantly less activity was demonstrated in the old than in the young group. The reduction in motor unit activity caused by the soft diet is considered to influence the morphologic and metabolic properties in the superficial masseter muscle but not in its motoneurons. The reduction in the oxidative enzyme activity of motoneurons with aging may occur regardless of the reduction in motor unit activity. © 1993 Wiley‐Liss, Inc.
Three‐dimensional reconstructions of the primary palate region in normal human embryos
Authors: Rudé Frank P. , Anderson Leigh , Conley David , Gasser Raymond F. 
Published: February 2005

AbstractOur knowledge of the precise spatial relationships of human primary palate morphogenesis remains poorly defined. This is due to intrinsic difficulties that exist in the study of the subject matter and a lack of adequate methodologies. We present a novel new method to allow precise three‐dimensional (3‐D) visualization of developing embryonic structures in previously sectioned embryos. In our study we focus on human primary palate development. Five normal human embryos from the Carnegie collection were used. 3‐D reconstructions appear similar to scanning electron micrographs (SEM); however, unlike in SEM studies, the original specimen has been previously sectioned histologically. 3‐D reconstruction from serial sections involved (1) histological preparation of specimen, 2) projection onto digitizing board, 3) digitization, 4) automated reassembly, and 5) relay to interactive optical disc recorder. Detailed observations of each reconstruction were then made. Data generated in this manner may also be used in the near future for quantitative morphometrics. Thus, 3‐D reconstruction techniques presented in this paper generated precise spatial information on the development of the human primary palate. © 1994 Wiley‐Liss, Inc.
Plasticity of innervation of the medulla of axillary lymph nodes in the rat after antigenic stimulation
Authors: Novotny G. E. K. , Heuer T. , Schöttelndreier A. , Fleisgarten C. 
Published: February 2005

AbstractThe purpose of this investigation was to test the hypothesis that activation of the immune system in rats will lead to changes in the density of innervation in lymph nodes. In order to reduce the variability between animals, the rats were reared under sterile conditions and immunostimulation was effected by subcutaneous application of bovine albumin in a region draining to the axillary lymph nodes of both sides. Control animals received an equivalent application of sterile physiological saline. The animals were sacrificed 10 days and 27 days and 4 months after immunostimulation. The nerves in the axillary lymph nodes were quantified by light microscopy in silver impregnated sections and at the ultrastructural level on ultrathin sections. The survival times were chosen so that the first group was in the ascending phase of antibody production, the second group at the peak, and the third group in the declining phase. Both at the light and ultrastructural levels, there were statistically significant differences in the density of innervation of medulla between the groups, with a particularly pronounced increase in the group 4 months after immunostimulation. At the ultrastructural level, there was also an increase in the density of incompletely ensheathed axonal profiles in the parenchyma of the medulla, while the nerves associated with blood vessels were not increased. We conclude that immunostimulation leads to morphological changes in the innervation of the medulla of axillary lymph nodes, that are consistent with the concept of functional activation of the autonomic nervous system through the immune system. © 1994 Wiley‐Liss, Inc.
Effects of peripheral axotomy on presynaptic axon terminals with GABA‐like immunoreactivity
Authors: Vaughan Deborah Whittaker 
Published: February 2005

AbstractThe facial nerve was unilaterally crushed at its exit from the stylomastoid foramen in three 3‐month old male rats. After 10 days survival, before the regenerating axons had reinnervated their target muscles, the facial nucleus was examined to determine central patterns of response in material prepared to demonstrate the presence of GABA‐like immunoreactivity with postembedding procedures using gold‐labeled secondary antibody. The uninjured nucleus served as a control. In both control and injured nuclei, the GABAergic terminals synapse with all parts of the motor neurons, except the axon, and exhibit diverse morphologies. GABAergic axon terminals vary in their size and in the electron density of their axoplasm and the majority of the terminals contain pleomorphic vesicle profiles that display a range in their packing density and size. In both control and injured facial nuclei, only ∼40% of the axon terminal profiles with pleomorphic vesicles exhibit GABA immunoreactivity. A morphometric analysis of the synaptic vesicle profiles in the GABA‐positive terminals reveals that following axotomy there is no change in the mean number of synaptic vesicle profiles per GABAergic terminal profile. However, the mean size of the synaptic vesicle profiles in these terminals shows an axotomy‐induced 50% increase, without change in the shapes of the enlarged vesicle profiles. Also, the numerical density of gold particles associated with the GABA‐positive terminals is consistently greater in the injured than the control axon terminals. In the control animals quantitative analysis of the relative distribution of all axon terminal profiles in the neuropil categorized by the shape of their vesicle profiles as round, pleomorphic, or flat is 57:37:6. Ten days after axotomy the ratio of these categories in the injured nucleus has shifted to 35:60:5. This study demonstrates that the functional state of a postsynaptic target can influence the morphology of vesicle profiles in presynaptic elements as well as patterns of its afferent input. © 1994 Wiley‐Liss, Inc.
Morphological, histochemical, and myosin isoform analysis of the diaphragm of adult horses, Equus caballus
Authors: Cobb Matthew A. , Schutt William A. , Hermanson John W. 
Published: February 2005

AbstractThe horse provides an interesting model for study of the structure and function of the mammalian diaphragm. Multiple regions of diaphragm from seven adult horses were prepared for histochemistry, immunocytochemistry, myosin heavy chain electrophoresis, and native myosin electrophoresis. Two additional adults were dissected to demonstrate myofiber and central tendon morphology and stained for acetylcholinesterase to demonstrate motor endplates. All regions of the adult diaphragm were histochemically characterized by a preponderance of type I fibers with some type IIa fibers. Type IIb fibers were absent in all adult specimens. Myosin heavy chain electrophoresis supported the histochemical study: two isoform bands were present on SDS gels that comigrated at the same rate as rat type I and IIa myosin heavy chain isoforms. No isoform was determined to comigrate with rat type IIb heavy chain isoforms. Native myosin isoform analysis revealed two isoforms that comigrated with rat FM‐4 and FM‐3 (FM = fast myosin) and two isoforms that comigrated with rat SM‐1 and SM‐2 (SM = slow myosin) isoforms. In some samples, a third slow native myosin isoform was observed that comigrated at the same rate as the SM‐3 of the equine biceps brachii muscle. This doublet (or “triplet”) of slow isoforms is unique to some horse muscles compared with other adult animals studied. It is not known if these multiple slow native myosin isoforms confer some functional advantage to the equine muscles. The adult equine diaphragm also differs in its morphology by having a large central tendon compared to that in other mammals, and is predominantly slow in fiber type and myosin isoform composition. © 1994 Wiley‐Liss, Inc.
Expression of TGFβ1/β3 during early chick embryo development
Authors: Sanders E. J. , Hu N. , Wride M. A. 
Published: February 2005

AbstractWe have used an antibody against a TGFβ peptide fragment to localize this growth factor in the early chick embryo from laying to the ten‐somite stage of development. Western blotting showed that the antibody reacted with both mammalian TGFβ1 and chicken TGFβ3. By immunocytochemistry we find that at the earliest developmental stage (stage X of Eyal‐Giladi and Kochav) immunoreactivity to this antibody is primarily located in the cells of the area opaca and marginal zone, as well as in the most peripheral edge cells of the blastoderm. The yolk is non‐reactive, except in a highly localized region subjacent to the edge cells. This pattern persists at stage XII, and at both stages individual isolated cells in the epiblast and hypoblast are also reactive. By the time to gastrulation, reactivity in the epiblast is polarized to the ventral extremity of the cells, and again some isolated cells in this layer are intensely immunoreactive. At this stage also, the endoderm cells, particularly those underlying the primitive streak, are positive, as are the mesoderm cells lateral to the streak. At somite stages, the neuroepithelium is not reactive but the ectoderm lateral to it is strongly positive. At the caudal primitive streak levels of early somite embryos, the ectoderm and endoderm are immunoreactive while the mesoderm loses the reactivity it showed at the early gastrulation stages. The neuroepithelial cells later show reactivity at their apical poles, and, as at the earlier stages, individual cells show intense labelling. These results indicate that TGFβ1 and/or TGFβ3 immunoreactivity is developmentally regulated from very early stages of morphogenesis in the chick, and together with data from earlier functional studies, suggest that this factor has roles in embryonic axis formation and in blastoderm expansion. © 1994 Wiley‐Liss, Inc.
Age‐dependent changes in the glial cell nests of the canine rhinencephalic allocortex. A morphometric study
Authors: Reihlen Anette , Weis Serge , Obermaier Gabriele , Dahme Erwin 
Published: February 2005

AbstractIn the present study, the morphological features as well as the age‐dependent changes of the glial cell nests (GCN) within the rhinencephalic allocortex of the dog are described. A combination of two stereological methods, i.e., Cavalieri's principle and the optical disector, was used to obtain unbiased estimates of the volumes of the whole brain, the allocortex, and the GCN. Furthermore, the numerical densities and total number of the two prevailing populations of undifferentiated cells within these nests were determined. Cells with medium‐sized dark nuclei (CMD) and cells with large pale nuclei (CLP) were distinguished. The volume of the GCN in relation to the volume of the allocortex decreased with increasing age. The numerical density and the total number of all cells of the GCN and of the CMD were reduced with age, whereas the numerical density and number of the CLP increased with advancing age. Similar morphological features as well as age‐dependent changes have already been described of the cell populations in the subependymal layer. Therefore, in analogy, we presume that the glial cells of the GCN have emigrated from the subependymal layer. The significance of these age‐dependent changes remains as obscure as does the function of the GCN. © 1994 Wiley‐Liss, Inc.
Early development of macrophages in intact and organ cultured hearts of rat embryos
Authors: Sorokin Sergei P. , McNelly Nancy A. , Hoyt Richard F. 
Published: February 2005

AbstractBackground: Macrophage precursors are present early in embryonic life, being demonstrable in placental and embryonic connective tissues of rats at the neurula stage and as potential macrophagees in the brain, liver, and lungs near the onset of organogenesis. We examined the development of macrophages in the heart and the possibility that they initially appear at sites of programmed cell death (apoptosis).Methods: Precursors were recognized by the binding of peroxidase‐coupled Griffonia simplicifolia isolectin B4 (GSA) on the cell membrane. Their capacity for conversion into macrophages was assayed in organ cultures; confirmation of the progeny as bona fide macrophages was obtained from their responses to particle exposure and macrophage colony‐stimulating factor (M‐CSF).Results:GSA + cells were first seen on gestational day 12 (4 mm embryos) as 2–3 cycling, nonvacuolated cells located in cardiac tissue outside the blood vessels. This population increased to ∼︁ 12 cells by day 14 (9 mm embryos). Two‐thirds were distributed along the bulbus cordis in the jellylike endocardium and a more densely cellular connective tissue closer to the aortic arches where apoptotic sites are expected to develop. Such sites were not found in serial glycol methacrylate sections through our 14‐day specimens, although in whole heart explants of this age an area of necrosis developed along the prospective line of bulbar endocardial fusion on the second day of organ culturing, and by then macrophages were fairly abundant. Organ culturing of 13‐day embryonic hearts also yielded large, highly vacuolated, GSA + mononuclear phagocytes. After a few days in culture most of the macrophages migrated onto the medium where they formed a tight corona of cells about the explants. They readily ingested iron oxide particles and concentrated supravitally administered neutral red in their vacuoles. Macrophages from 14‐day cultures exposed to M‐CSF developed significantly larger coronas than macrophages from explants grown in serum‐rich control medium (p < 0.001). In the presence of cytokines, moreover, these cardiac macrophages survived as many as 100 (92 “postnatal”) days.Conclusions: Macrophage precursors first appear in embryonic rat hearts well before they are needed to clear debris generated by programmed cell death and are capable of rapid conversion into outright phagocytic cells as early as the 13th prenatal day. © 1994 Wiley‐Liss, Inc.