bluuebunny/crossref_metadata_2025_split huggingface dataset:
Satellite cell activation after muscle damage in young and adult rats
Authors: Jacobs S. C. J. M. , Wokke J. H. J. , Bär P. R. , Bootsma A. L. 
Published: February 2005

AbstractBackground: Level exercise leads to focal structural damage in muscle fibers and to an increase of creatine kinase in the blood. We questioned whether it also induces activation of young and adult muscle satellite cells toward proliferation.Methods: Rats of two different ages, 6 and 16 weeks, were forced to run on a level treadmill and killed at different time intervals. The temporal profile, up to 3 weeks, of muscle damage was investigated by quantification of the focally disturbed fiber area in longitudinal sections of the m. soleus. Bromodeoxyuridine (BrdU) was injected before death to determine the labeling index of satellite cells. Labeled and unlabeled satellite cells, myonuclei, and fibers were counted in cross sections of the belly part of the muscles.Results: The muscle fiber damage differed in both amount and temporal profile between young and older animals. Damage was already visible immediately after running. However, whereas in the younger animal the amount of damage increased gradually in time until 8% at 48 hours and disappeared to almost control levels at 1 week after running, in the older animals the amount of damage was lower but remained present for at least 2 weeks. The cell kinetic data on both groups showed a proliferation response of satellite cells throughout the muscle. The effects were most pronounced in the older rats. In these rats a large increase of the labeling index was found between 24 hours and 1 week, whereas the total number of satellite cells was consistently higher from 2 days on until 2 weeks after running. In the younger animals roughly the same time pattern was observed.Conclusion: Since the damage differed in amount and time between the two age groups, we conclude that the quick and huge proliferation response is due to leakage of mitogenic factors through small membrane disruptions that are generated during the exercise itself. © 1995 Wiley‐Liss, Inc.
Comparison of left and right vertebral artery intracranial diameters
Authors: Mitchell Jeanette , McKay Alison 
Published: February 2005

AbstractBackground: The vertebral artery is vulnerable to mechanical injury, especially in the region of the first and second cervical vertebrae, with resultant thrombus and/or emboli formation, often found at the vertebro‐basilar junction. Such vascular injuries and associated neurological insults have been documented repeatedly in the literature as following cervical spine manipulation, when movements of the head and neck can cause compression and/or stretching of the vertebral artery and alterations in its blood flow. This has particular clinical relevance if a patient has a hypoplastic vertebral artery. Such persons may be considered at risk as regards vascular accidents following manipulation of the cervical spine. The aim of this study was to measure and compare the intracranial diameters of the left and right vertebral arteries in groups of black and white male and female South African subjects. Methods: Cadaver material from 58 specimens was processed for light microscopy, and measurements of inner (lumen only) and outer (lumen, tunica intima, and tunica media) diameters taken and compared, using the t‐test. Results: Data analysis revealed a significant difference between the left and right vertebral artery intracranial diameters in the white female group only (N=8). Conclusions: Such a statistically significant difference implies a difference of biological importance and it is suggested that this particular group of subjects may be a high‐risk group as regards vascular accidents following cervical spine manipulation. © 1995 Wiley‐Liss, Inc.
Macrophage‐lymphocyte cell clusters in the hypothalamic ventricle of some elasmobranch fish: Ultrastructural analysis and possible functional significance
Authors: Torroba M. , Chiba A. , Vicente A. , Varas A. , Sacedón R. , Jimenez E. , Honma Y. , Zapata A. G. 
Published: February 2005

AbstractBackground: Previous studies have demonstrated the existence of lympho‐haemopoietic tissue in the meninges and choroid plexuses of various primitive vertebrates, including the stingray Dasyatis akajei and in early human embryos. In the present study, we extend these results analyzing macrophage‐lymphocyte cell clusters found in the floor of the hypothalamic ventricle of several specimens of elasmobranchs.Methods: After aseptical isolation of the brain from several specimens of smooth dogfish Triakis scyllia, cloudy dogfish Scyliorhinus torazame, gummy shark Mustelus manazo, and stingray Dasyatis akajei their hypothalamic regions were processed routinely by light, scanning, and transmission electron microscopy.Results: The study of serial histological sections demonstrated that the macrophage‐lymphocyte cell clusters proceeded from the meningeal lymphohaemopoietic tissue, reaching the ventricular lumen along large blood vessels. In this tissue, macrophages, different sized lymphocytes, lymphoblasts, granulocytes, monocytes, and developing and mature plasma cells were closely packed among a meshwork of fibroblastic reticular cell processes. It never invaded the brain parenchyma. A cell layer of glial elements and a continuous basement membrane interposed between the lymphoid tissue and the neural elements although some macrophages had migrated across the ependymal cell layer. In the ventricular lumen very irregular macrophages with long cell processes and containing abundant engulfed material of unknown origin formed big cell clusters with neighboring lymphocytes, lymphoblasts, and plasma cells, similar to those described during the immune response. Moreover, electron lucent cells which resembled the antigen‐presenting cells of higher vertebrates established intimate surface cell contacts with the surrounding lymphocytes. In the third ventricle of several specimens of gummy shark, Mustelus manazo, morphologically similar cell clusters appeared but these were not connected to the meningeal lympho‐haemopoietic tissue. No intraentricular cell aggregates were found in the stingray brain.Conclusions: Although we cannot rule out that these macrophage‐lymphocyte cell clusters represent a permanent structure in the elasmobranch brain they rather seem to be only established after specific stimulation for preventing the entrance of noxious, foreign materials into the elasmobranch brain parenchyma. © 1995 Wiley‐Liss, Inc.
Pulmonary lymphatics and their spatial relationship to venous sphincters
Authors: Aharinejad S. , Böck P. , Firbas W. , Schraufnagel D. E. 
Published: February 2005

AbstractBackground: Pulmonary lymphatics are critical to clearing lung fluid. Although their structure can be shown with light and transmission electron microscopy, scanning electron microscopy of their casts can better show their number, size, shape, distribution, and degree of filling. This technique has identified four forms of lung lymphatics, but these forms have not been fully evaluated by tissue microscopy. A most important site of pulmonary edema formation, the pulmonary capillary, is just upstream from small veins which have focal, smooth muscle tufts termed venous sphincters. Because of their constricting potential, these sphincters may control lung perfusion and cause edema.Methods: With light and transmission electron microscopy of tissue and scanning electron microscopy of casts, the lymphatic forms were explored in relation to the tissue anatomy in rats without pulmonary edema and with mild‐to‐moderate edema caused by extended vascular rinsing.Results: The edematous lungs had increased sacculo‐tubular lymphatics adjacent to the venous sphincters. These lymphatics were in the adventitial connective tissue and were partially endothelialized. As lymphatics became more tubular their endothelium became more complete. Collagen fibers traversed the lumen of these lymphatics even where endothelial cells were present and caused the lines on the surface of the lymphatic casts. Overlapping endothelial cells caused clefts on the casts.Conclusions: Scanning electron microscopy of lymphatic casts better defines their ultrastructure and shows the spatial relationship of veins and their sphincters to venous lymphatics. Sphincter contraction may influence pulmonary lymph production which could affect other aspects of regional lung perfusion. © 1995 Wiley‐Liss, Inc.
Central cardiovascular shunts in the perinatal marsupial
Authors: Runciman S. I. C. , Gannon B. J. , Baudinette R. V. 
Published: February 2005

AbstractBackground. Marsupials are born at an early stage of development after a short period of gestation. In this study the nature and timing of closure of the central cardiovascular shunts was investigated.Methods. Light and scanning electron microscopy were used to determine changes in central cardiovascular shunts in eight marsupial species with gestation periods of between 12.5 and 36.5 days and birth weights ranging from 12.5 mg to 740 mg. Laboratory mice with a birth weight of about 1,000 mg and a gestation period of 21 days were included for comparison.Results. Marsupials have a ductus arteriosus and an interatrial communication. The former closes rapidly after birth in the marsupial; however the interatrial communication is in the form of a fenestrated septum, which closes as result of tissue proliferation over a period of days after birth. An additional central shunt, an interventricular foramen, was found to persist in three species for a short time after birth. In one species, the eastern native cat, Dasyurus viverrinus, which has a gestation period of about 19 days and low birth weight of about 12.5 mg, in addition to the two common shunts there was a large interventricular communication and septation of the outflow tract was incomplete.Conclusion. In adapting from intra‐uterine life, it seems that marsupials have adopted different, but equally effective strategies, with regard to the circulatory system. © 1995 Wiley‐Liss, Inc.
Growth of the myocardial volumes of the individual cardiac segments in the rat embryo
Authors: Knaapen M. W. M. , Vrolijk B. C. M. , Wenink A. C. G. 
Published: February 2005

AbstractBackground: Although the growth of the developing heart in relation to an increase of ventricular systolic pressure and the growth of the entire embryo during development has been described, no data are available on the growth of the individual segments and intersegmental junctions. Because these different portions are known to function differently, the need for data on their individual development is obvious.Methods: We have measured the volumes of these different compartments by Cavalieri's point counting method in rat embryos from 11 to 17 days.Results: It is shown that sinus venosus and sinu‐atrial junction as well as the main compartments atrium, inlet, and proximal outlet segment grow roughly proportional to the total myocardial volume. Atrio‐ventricular canal and distal outlet segment show a restricted growth and their proportional volumes decrease in time. The inlet segment is the most important part of the ventricular mass at 11 days of gestation, when it is still larger than the proximal outlet segment and, thus, takes the greater part in systolic action of the ventricular mass. The growth of the primary fold increases from day 13 onwards and can be considered as part of the wall of the inlet segment which gives rise to the main part of the ventricular septum.Conclusions: The timing of the septal volume increase fits with qualitative descriptions of ventricular septation. The atrio‐ventricular canal and distal outlet segment have an important constrictive function in early stages, when valves are not yet present. Slow conduction and contraction patterns have been reported to be a characteristic feature of these portions of the embryonic heart. With development of valves these segments are loosing their mechanical function and, thus, their proportional volume declines. © 1995 Wiley‐Liss, Inc.
Integrin distribution during heart development in the long ‐ tailed macaque (M. fascicularis)
Authors: Pow Craig S. T. , Hendrickx Andrew G. 
Published: February 2005

AbstractBackground: Cardiogenesis appears to require cellular and extracellular matrix interactions for normal development. Although numerous matrix components have been identified within embryonic heart tissue, the distribution, and function of their respective integrin receptors, implicated as mediators of cell‐matrix interaction, remain unknown in primates.Methods: Using immunocytochemistry, the localization of integrin subunits α1, α5, α6, and β1 were examined in hearts of macaque embryos during early septation and trabeculation, and compared to the distribution of the integrin ligands laminin, collagen IV, and fibronectin.Results: At stage 11, α5 reactivity was limited to endothelial cells in the primitive heart. At stage 13, α1 and α5 were additionally detected on mesenchymal cells within the endocardial cushions. On myocardial cells at this stage, α5 stained weakly in all regions, but α1 was not expressed. The α6 subunit appeared more prominent in both stages, being present on myocardial cells throughout the heart, particularly on the basal surface of myocardial cells adjacent to the myocardial basement membrane. Inconsistent reactivity occurred on endothelial cells however, and no staining for α6 was detected on cushion mesenchymal cells. At both stages, β1 reactivity was present on all cardiac cell population and overlapped that of the α‐subunits examined. Laminin, collagen IV, and fibronectin were detected at each stage and their distribution correlated with that described for the subunits.Conclusions: These results show specific selective patterns of expression for the subunits which are comparable to the localization of their known glycoprotein ligands and suggest defined roles for individual integrins during heart development in primates. © 1995 Wiley‐Liss, Inc.
Type VI collagen in mouse masseter tendon, from osseous attachment to myotendinous junction
Authors: Senga Katsuhiro , Kobayashi Miya , Hattori Hisashi , Yasue Kazuki , Mizutani Hideki , Ueda Minoru , Hoshino Takeshi 
Published: February 2005

AbstractBackground and Methods: The association of masseter tendon type VI collagen with other extracellular matrix (ECM) components was examined from osseous attachment to myotendinous junction by immunohistochemistry and transmission electron microscopy with ATP treatment and enzyme digestion.Results: In the tendon proper, fibrocytes extended their processes among bundles of striated collagen fibrils and associated with adjacent cells through amorphous materials, thus forming a three‐dimensional network. The amorphous or filamentous material was observed around the fibrocyte cell body and along the cell processes, where the localization of type VI collagen was confirmed by immunohistochemistry using anti‐type VI collagen antibody. After treatment with 20 mM adenosine 5′‐triphosphate (ATP), 100 nm periodic fibrils, an aggregated form of type VI collagen, were formed in the place where amorphous or filamentous material was present before the treatment. In myotendinous junction, the ATP‐aggregated periodic fibrils were observed to associate with the external lamina of the muscle cells as well as among junctional tendon collagen fibrils. In the tendonbone boundary, ATP‐aggregated periodic fibrils were observed around fibrocartilage‐like cells in the uncalcifying area but not in the calcification front. Prolonged ATP treatment or hyaluronidase predigestion caused the formation of type VI collagen periodic fibrils in the area near the calcified matrix.Conclusions: The distribution of type VI collagen in mouse masseter tendon is different in different anatomical position. This may reflect the different functional demand for this collagen. © 1995 Wiley‐Liss, Inc.
Exocytosis of secretory granules in the juxtaglomerular granular cells of kidneys
Authors: Ogawa Kazushige , Yamasato Maki , Taniguchi Kazuyuki 
Published: February 2005

AbstractBackground: There is little agreement as to the secretory process of renin granules in juxtaglomerular granular cells (JG cells) of kidneys, although a large number of studies of the regulation of renin secretion have been reported.Methods: The structural correlation between the stimuli and the secretory process was examined in mouse JG cells on renal cortical slice incubated with the beta‐adrenergic agonist, isoproterenol; the loop diuretic, furocemide; the Ca2+ chelator, EGTA; and the actin filament‐disrupting agent, cytochalasin B.Results and Conclusions: Treatment with isoproterenol (10−5−10−3 M) or furocemide (10−3M) in Ca2+‐containing medium did not significantly affect the ultrastructure of JG cells. In slices incubated with isoproterenol or furocemide in the Ca2+‐free medium, JG cells occasionally contained a few electron‐lucent granules at the cell periphery in addition to the electrondense mature granules observed in the control slices. On rare occasions, the JG cells displayed omega‐shaped cavities with electron‐lucent matrices, a feature similar to the contents of electron‐lucent granules. Cytochalasin B markedly promoted the effects of these stimulants in Ca2+‐free medium. These findings suggest the participation of actin filament disassembly in the exocytotic process of the mature granules in JG cells. © 1995 Wiley‐Liss, Inc.
Satellite cells and myonuclei in long‐term denervated rat muscles
Authors: de Castro Rodrigues Antonio , Schmalbruch Henning 
Published: February 2005

AbstractBackground: The percentage of satellite cells rapidly decreases in aneurally regenerating soleus muscles of rat. Also denervation of intact muscles causes fiber loss and regeneration, but the fate of satellite cells is unknown; myonuclei have been suggested to undergo changes resembling those in apoptotic cells.Methods: Rat soleus and extensor digitorum longus (EDL) muscles were denervated at birth or at age 5 weeks and investigated after periods of up to 38 weeks. At least 400 myonuclei in each muscle were assessed by electron microscopy, and satellite cell nuclei were counted. In sity nick translation and tailing were performed after 30 weeks denervation in order to demonstrate DNA breaks associated with apoptosis.Results: Myotubes indicating regeneration were prominent in the adult denervated soleus and deep layers of EDL muscles after 7 weeks and in the superficial parts of EDL muscle after 16 weeks. The percentage of satellite cell nuclei slowly decreased to less than one fifth of normal after 20–30 weeks. Almost all satellite cells had vanished 10 weeks after neonatal denervation. Degenerating myonuclei in adult, but not in neonatally denervated muscles, remotely resembled apoptotic nuclei of lymphocytes, but no evidence of DNA breaks was found.Conclusion: Denervation of rat skeletal muscles causes, in addition to fiber atrophy, loss of fibers with subsequent regeneration. Proliferation of satellite cells under aneural conditions may lead to exhaustion of the satellite cell pool. This process is more rapid in growing than in adult muscles. Myonuclei in denervated muscles do not show DNA breaks which can be demonstrated by in situ nick translation. © 1995 Wiley‐Liss, Inc.
Microvasculature of the rabbit urinary bladder
Authors: Hossler Fred E. , Monson Frederick C. 
Published: February 2005

AbstractBackground: The urinary bladder requires a rich blood supply to maintain its functions, the storage and release of urine. Specialized properties of the bladder vasculature might be anticipated to ensure the integrity of this blood supply, because it is known that blood flow is reduced by distension during bladder filling. However, the bladder vasculature has been described in detail only at the gross level. A comprehensive, threedimensional view of the blood supply to the bladder wall is presented here.Methods: The microvasculature of the bladder of male New Zealand white rabbits was described using the combination of vascular corrosion casting, alkali digestion, light microscopy, and scanning and transmission electron microscopy. Following administration of an anticoagulant and an overdose of anesthetic, the abdominal aorta was cannulated just above the inferior mesenteric artery to permit flushing of the distal vasculature. The bladder vasculature was cleared of blood with buffered saline and then either perfuse‐fixed with buffered 2% glutaraldehyde and sectioned, or filled with “Mercox” resin to prepare vascular corrosion casts. Casts were cleaned with NaOH, formic acid, and water. In some cases fixed bladders were partially digested with NaOH to expose the mucosal capillary plexus.Results: The bladder is supplied with blood by single, left and right vesicular branches of the internal or external iliac arteries. The serpentine vesicular arteries extend along the lateral borders of the bladder from base to apex just deep to the serosal surface and send dorsal and ventral branches to supply the dorsal and ventral bladder walls. Veins accompany the arteries and exhibit numerous valves. A very dense complex of vessels at the apex of the bladder apparently serves to accommodate bladder distension. The muscularis and submucosa contains few vessels, but the mucosa is well vascularized. An especially dense capillary plexus is present in the lamina propria at its junction with the transitional epithelium. In the relaxed bladder these capillaries lie in grooves formed by the basal layers of the epithelium. The endothelial cells of these capillaries display few cytoplasmic vesicles and are continuous or fenestrated. These capillaries are often invested with pericytes. The mucosal capillary plexus may be associated with an epithelial transport function or may be necessary for urothelial metabolism or maintenance of the barrier function of the urothelium. Unusual capillary tufts, possibly associated with vascular lymphatic tissue, are found associated with the main vessels on the lateral walls in the basal half of the bladder.Conclusions: These methods present a clear, comprehensive, three‐dimensional view of the microvasculature of the bladder wall. They also identify several unique features of this vasculature and provide a basis for studies of the response of this vasculature to pathologic states and experimental manipulation. © 1995 Wiley‐Liss, Inc.