bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of maternal bilateral ureteral ligation on the differentiation of glomerular anionic sites in fetal rat kidney
Authors: Okada Toshiya , Morikawa Yoshio 
Published: February 2005

AbstractEffects of maternal bilateral ureteral ligation on the differentiation of glomerular anionic sites in fetal kidney were studied with the colloidal iron method. The ligation was performed on days 17, 19, and 21 of pregnancy, and the animal were euthanized 1 day after each ligation. On fetal day 20, in the fetuses from ligated mothers, colloidal iron was concentrated in laminae rarae interna and externa of the glomerular basement membrane. In the fetuses from sham‐ligated mothers, however, a different pattern of iron distribution was noted. In most areas of the glomerular basement membrane, colloidal iron was randomly distributed as in both fetuses of fetal day 18. In the remaining areas, the same pattern of colloidal iron distribution as was noted in the fetuses from ligated mothers of fetal day 20 was observed. On fetal day 22, colloidal iron was densely accumulated in laminae rarae interna and externa of the glomerular basement membrane in both groups. However, the iron‐free zone was slightly thicker in the fetuses from the ligated mothers. These findings suggest that maternal bilateral ureteral ligation accelerates the differentiation of glomerular anionic sites in the kidney of fetal rats.
A method for preparing skeletal muscle fiber basal laminae
Authors: Carlson Edward C. , Carlson Bruce M. 
Published: February 2005

AbstractPrevious attempts to prepare skeletal muscle basal laminae (BL) for ultrastructural analyses have been hampered by difficulties in successfully removing skeletal muscle proteins and cellular debris from BL tubes. In the present study we describe a two phase method which results in an acellular muscle preparation, the BL of which are examined by light, transmission electron, and scanning electron microscopy. In the first phase, excised rat extensor digitorum longus muscles are subjected to x‐radiation and then soaked in Marcaine to inhibit muscle regeneration and to destroy peripheral muscle fibers. The muscles are then grafted back into their original sites and allowed to remain in place 7–14 days to allow for maximal removal of degenerating muscle tissue with minimal scar tissue formation. In the second phase, the muscle grafts are subjected sequentially to EDTA, triton X‐100, DNAase, and sodium deoxycholate to remove phagocytizing cells and associated degenerating muscle tissue. These procedures result in translucent, acellular muscle grafts which show numerous empty tubes of BL backed by endomysial collagenous fibers. These preparations should be useful for morphological analyses of isolated muscle BL and for possible in vitro studies by which the biological activity of muscle BL can be examined.
Extracellular matrix of the developing heart in normal and cardiac lethal mutant axolotls, Ambystoma mexicanum
Authors: Fransen Margaret E. , Lemanski Larry F. 
Published: February 2005

AbstractAs part of an ongoing study of heart development in normal and cardiac lethal mutant axolotls ( Mexican salamanders) we examined the extracellular matrix (ECM) by microscopical methods. With scanning electron microscopy we are unable to detect ECM on the apical surface of cells of the early cardiogenic mesoderm. During the period of lateral plate migration, which coincides with the period of cardiogenic induction of mesoderm by anterior endoderm, there is little ECM, aside from some microfibrils, on the basal surface of the endoderm or mesoderm of the pharyngeal region. Later, a basal lamina (BL) is found on the endoderm and along portions of the developing endocardial and myocardial tubes. By the time of heartbeat initiation the BLs are complete and invested with striated collagen‐like fibrils that are sparsely distributed in the “cardiac jelly” of normal and mutant hearts. Striated fibril deposition, which increases with time, is generally random in orientation, with the exception of some regions where there is a preferred directionality. During the post‐hatching period striated fibrils appear in the subepicardial space. In addition, branching fibers that are probably elastin appear in the bulbus arteriosus. In these later stages the density of fibrils in the cardiac lethal mutant heart is much less than normal. Indirect immunofluorescent microscopy reveals laminin and fibronectin in the basal; aminae of the endocardial and myocardial tubes of both normal and cardiac llethal mutant hearts. In addition, punctate and fibrillar staining for fibronectin, and punctate staining for laminin are found in the cardiac jelly. These matrix proteins are not abundant at the apical (exterior) surface of the myocardium until the epicardium appears. These results are similar to reports on ECM in other developing vertebrate hearts.
Tetracycline administration restores osteoblast structure and function during experimental diabetes
Authors: Sasaki Takahisa , Kaneko Haruki , Ramamurthy Nungavaram S. , Golub Lorne M. 
Published: February 2005

AbstractOsteopenia is a recognized complication of diabetes mellitus in humans and experimental animals. We recently found that tetracyclines prevent osteopenia in the streptozotocin‐induced diabetic rat and that this effect was associated with a restoration of defective osteoblast morphology (Golub et al., 1990). The present study extends these initial ultrastructural observations by assessing osteoblast function in the untreated and tetracycline‐treated diabetic rats. After a 3‐week protocol, non‐diabetic control and diabetic rats, including those orally administered a tetracycline, minocycline (MC), or a non‐antimicrobial tetracycline analog (CMT), were perfusion‐fixed with an aldehyde mixture; the humeri were dissected and processed for ultracytochemical localization of alkaline phosphatase (ALPase) and Ca‐ATPase activities. Some rats from each experimental group received an intravenous injection of 3H‐proline as a radioprecursor of procollagen, and the humeri were processed for light microscopic autoradiography. In addition, the osteoid volume in each experimental group was quantitatively examined by morphometric analysis of electron micrographs.During the diabetic state, active cuboidal osteoblasts in the endosteum of control rats were replaced by flattened bone‐lining cells that contained few cytoplasmic organelles for protein synthesis (Golgi‐RER system), and active transport (mitochondria). Treating diabetic rats with MC, and even more so with CMT, appeared to “restore” osteoblast structure. During diabetes, bone‐lining cells incorporated little 3H‐proline or secreted little labeled protein and produced only a very thin osteoid layer. Tetracycline administration to the diabetics increased both the incorporation of 3H‐proline by osteoblasts and their secretion of labeled protein toward the osteoid matrix, in a pattern similar to that seen in the non‐diabetic controls. Intense alkaline phosphatase (ALPase) activity was cytochemically demonstrated along the plasma membranes of osteoblasts in the non‐diabetic control rats, but was completely absent from the bone‐lining cells in the diabetics. Similar to that described above, CMT therapy restored the ALPase activity in the diabetic osteoblasts and the effect of MC was less dramatic. The distribution and intensity of Ca‐ATPase in the osteoblast‐plasma membranes of the different groups of rats were similar to that of ALPase, except for the absence of detectable Ca‐ATPase in the MC‐treated diabetics. These results suggest that diabetes‐induced osteopenia reflects, al least in part, impaired osteoblast structure and function and that tetracyclines, by a non‐antimicrobial mechanism, may prevent this bone deficiency by normalizing these bone‐lining cells.
Evidence that vinculin is co‐distributed with actin bundles in ectoplasmic (“junctional”) specializations of mammalian sertoli cells
Authors: Pfeiffer David C. , Wayne A. 
Published: February 2005

AbstractEctoplasmic specializations of Sertoli cells are actin containing structures found at sites of attachment to spermatids and to neighboring Sertoli cells. We suspect that these cytoskeletal structures are a form of actin‐associated adhesion junction. If this is true, then molecular components, such as vinculin, that characterize actin‐associated adhesion junctions in general should be present in ectoplasmic specializations.In this paper we have used two approaches to verify the prediction that vinculin is a component of ectoplasmic specializations. First, we have used fluorescence microscopy to probe immunologically for vinculin in ectoplasmic specializations associated with spermatids of the ground squirrel. Second, we have used immunogold techniques to probe for vinculin in ectoplasmic specializations of rat testis.Our results indicate that the immunological probe for vinculin was reactive with ectoplasmic specializations. In single label fluorescence experiments, linear patterns obtained with the vinculin probe were similar to those obtained with probes for filamentous actin. In double label experiments, the vinculin probe was codistributed with the actin probes. In immunogold studies, specific labelling with the probe for vinculin occurred in ectoplasmic specializations both at sites of attachment to spermatids and adjacent to basal Sertoli cell junctions. Moreover, gold particles were concentrated adjacent to filament bundles within each ectoplasmic specialization.Our results support the conclusion that vinculin is present in ectoplasmic specializations. Further, they indicate that vinculin is co‐distributed with actin bundles within each ectoplasmic specialization.
Immunocytochemical localization of follicle regulatory‐protein (FRP) in testis
Authors: Ahmad Nazir , Pringle Jean , Toppari Jorma , Tonetta Sharon A. , Dizerega Gere S. 
Published: February 2005

AbstractFollicle regulatory protein (FRP) can exert paracrine control over follicular development. It is synthesized by the granulosa cells of the developing follicles and was localized in the cytoplasm of the mural cells by immunocytochemistry. When administered to male dogs and rats, FRP causes impairment of spermatogenesis. In the intact male rat, it has been postulated that FRP manifests its effects at a stage prior to the conversion of testosterone to dihydrotestosterone. Sertoli cells of the seminiferous tubules are implicated in testosterone metabolism. Furthermore, Sertoli cells in male gonads are regarded as the counterpart of granulosa cells in ovaries. The exact source of FRP in the male is not known. Therefore, it was of interest to study the localization of FRP in the male gonads. Testicular sections of the pig, dog, cat, rat, mouse, monkey, and man were immunocytochemically stained with monoclonal antibody to porcine FRP of ovarian origin. Sections of pig ovaries were used as controls throughout the study. Specificity of immunocytochemical localization was established by preabsorption. FRP antibody predominantly localized to the interstitial compartment of the pig testis. In the seminiferous tubules, FRP localization was limited to basal spermatogonia and Sertoli cells of tubules at few specific stages of spermatogenesis. The study also showed that the monoclonal antibody against porcine FRP is species‐specific. Antibody binding was found only in pig testis, whereas tissues from the cat, dog, mouse, rat, monkey, and man did not display any immunocytochemical reaction. Since in the pig testis, Sertoli cells at specific stages of spermatogenesis showed FRP localization, it would appear that FRP production is not being carried out by Sertoli cells at other stages. Due to the fact that all of the interstitial cells stained with FRP and some of the Sertoli cells were stained with FRP‐antibody, it is not possible to ascertain the exact cell type responsible for FRP synthesis and secretion in testis using immunocytochemistry. Since the antibody to FRP of ovarian follicular fluid origin bound to various testicular cells, it would appear that FRP or a protein of similar nature may also be present in the testes.
Solitary neuroendocrine cells and neuroepithelial bodies in the lower airways of embryonic, fetal, and postnatal sheep
Authors: Balaguer Luis , Romano Jacinta 
Published: February 2005

AbstractThe sheep pulmonary intraepithelial APUD system was studied by histochemical, immunocytochemical, and electron microscopy techniques during different periods of lung development: embryonic, fetal (pseudoglandular, canalicular, and alveolar), and postnatal.The cells of the ovine pulmonary intraepithelial APUD system were found randomly distributed throughout the conducting and respiratory or undifferentiated airways. They appeared as isolated cells (solitary neuroendocrine cells) or in groups (neuroepithelial bodies).These cells were argyrophilic and immunoreactive for neuron‐specific enolase but were not argentaffin. Ultrastructurally they were characterized by a basal position in the respiratory epithelium and by the presence of neurosecretory granules (dense‐core vesicles) ranging between 65 and 230 nm of diametre.Quantitative studies showed that single neuroendocrine cells were more numerous in distal conducting airways and at fetal stages.The earliest identifiable argyrophilic and NSE‐immunoreactive neuroendocrine cells in sheep airways appeared at gestational week 5, close to the term of the embryonic period.
Mechanoreceptors of the hard palate of the mongolian gerbil include special junctions between epithelia and meissner lamellar cells: A comparison with other rodents
Authors: Tachibana Tamiko , Fujiwara Naoki , Nawa Tokio 
Published: February 2005

AbstractAs a part of our comparative morphological study of mechanoreceptors in rodent oral mucosae, the hard palate of the mongolian gerbil (a kind of sand rat) was investigated by light and electron microscopy. Subepithelial connective tissue papillae of palatine rugae contained a dense distribution of lamellated corpuscles that showed an ultrastructure similar to that of Meissner corpuscles of primates. The corpuscles in the palate of the mongolian gerbil, however, frequently formed compound large corpuscles with a palisade‐like extension. Antemolar rugae predominated in containing such compound “Meissner” corpuscles. Superficial cytoplasmic lamellae of the corpuscles closely adhered to overlying epithelial cells without an intervening basal lamina. Although a small number of simple corpuscles was seen in the first antemolar ruga, no similar corpuscles were encountered in other parts of the palate. On the other hand, numerous Merkel cellnerve endings were seen in epithelial pegs and sometimes in epithelial ridges of palatine rugae. Quinacrine labelling showed that intermolar rugae contained a rather dense distribution of Merkel cells in comparison with antemolar rugae. The present and previous data indicate that the pattern of palatine mechanoreceptors of the mongolian gerbil is analogous to that of the mouse, but not of the rat.
Numbers and proportions of unmyelinated axons at cervical levels in the fasciculus gracilis of monkey and cat
Authors: Garrett Lizabeth , Coggeshall Richard E. , Patterson Joel T. , Chung Kyungsoon 
Published: February 2005

AbstractThe present study is a quantitative analysis of the unmyelinated fiber population in the fasciculus gracilis of the second cervical segment of cat and monkey. We find that unmyelinated fibers represent 13.7% of the total fiber population in this pathway in the cat and 18.9% in the monkey (Macaca fascicularis). The existence of such large numbers of these axons suggests that there may be a sizeable ascending fine primary afferent pathway in the fasciculus gracilis in cat and monkey whose destination is presumably the dorsal column nuclei. These findings are of interest in regard to classic ideas that the afferent fibers in the dorsal columns are large myelinated fibers that convey fine discriminative information to the dorsal column nuclei.
Morphometry and histoenzymology of the hamster tenuissimus and its muscle spindles
Authors: Patten Robert M. , Ovalle William K. 
Published: February 2005

AbstractMuscle spindles and extrafusal fibers in the tenuissimus muscle of mature golden Syrian hamsters were studied morphologically and quantitatively using several light microscopic techniques. Muscle spindles were identified in serial‐transvere frozen‐sections of whole muscles stained with hematoxylin and eosin. Five tenuissimus muscles were examined from origin to insertion, and the locations of individual receptors were plotted in camera‐lucida reconstructions. Spindles were found in proximity to the main neurovascular bundle in the central core of each muscle. A range of 16–20 receptors was noted per muscle. The mean muscle spindle index (the total number of spindles per gram of muscle weight) was 503 and the average spindle length was 7.5 mm. Oxidative enzyme and myosin adenosine‐triphosphatase (ATPase) staining profiles were also evaluated in the intrafusal and extrafusal fibers in each muscle. Even numbers of type I and type IIA extrafusal fibers were distributed homogeneously throughout all muscle cross‐sections. Histochemical staining patterns varied along the lengths of the three intrafusal fiber types. Nuclear chain fibers possessed staining properties similar to the type IIA extrafusal fibers and exhibited no regional variations. Bag1 fibers displayed staining variability, particularly when treated for myosin ATPase under acid preincubation conditions. Some spindles were isolated under darkfield illumination and then either treated with 7‐nitrobenz‐2‐oxa‐1, 3‐diazole (NBD)‐phallacidin to detect filamentous actin by fluorescence microscopy, or prepared for conventional scanning electron microscopy (SEM). By fluorescence microscopy, a registered actin banding‐pattern was observed in the sarcomeres of the intrafusal fibers, and variations in the intensity of banding were noted amongst different fibers. SEM revealed punctaie sensory nerve endings that adhered intimately to the surfaces of underlying intrafusal fibers in the equatorial and juxtaequatorial regions. By transmission electron microscopy (TEM) these endings appeared crescent‐shaped and were enveloped by external laminae. Each profile contained numerous mitochondria and cytoskeletal organelles. The high spindle density observed in this muscle suggests that the hamster tenuissimus may function in hindlimb proprioception.
The differentiation of the skin and its appendages. I. Normal development of papillary ridges
Authors: Morohunfola Kehinde A. , Jones Terrel E. , Munger Bryce L. 
Published: February 2005

AbstractIn the present study, the normal development of papillary ridges was studied in the volar pads of both fore and hindpaws of the opossum, Monodelphis domesticus. At birth, the developmental state of the opossum's paws is equivalent to that of a six‐week human embryo. The development of papillary ridges in the opossum occurs entirely postnatally and the hindpaw lags behind the forepaw by at least four days in most developmental parameters. Papillary ridge formation is preceded by four events: skin innervation, Merkel cell differentiation, mesenchymal condensation, and epidermal proliferation. The apical pads at the tips of the digits and the interdigital pads between the heads of the metacarpals (or metatarsals) have a unique pattern of innervation and mesenchymal content as compared to the non‐pad skin. Each pad is innervated by a prominent nerve trunk and axons ascend towards the epidermis providing a density of innervation that exceeds that in the non‐pad epidermis. Merkel cells are absent in non‐pad epidermis but present in the pads prior to the onset of formation of papillary ridges. A loose aggregation of mesenchyme forms the core of the pads and the superficial dermis is more cellular in the pads as compared to the equivalent dermis in surrounding non‐pad skin. Developing papillary ridges always contained Merkel cell‐axon complexes.Merkel cell axon complexes serve as the anatomical substrate of slowly adapting (SA) mechanoreceptors. The presence of these complexes during early skin differentiation is consistent with the use of the opossum's forepaw in climbing to the nipple, but also suggests other possible functions. We hypothesize that the nervous system might play a role in the timing or patterning of the formation of papillary ridges.
Interspecies comparison of cellular localization of the cyanide metabolizing enzyme rhodanese within olfactory mucosa
Authors: Lewis J. L. , Rhoades C. E. , Bice D. E. , Harkema J. R. , Hotchkiss J. A. , Sylvester D. M. , Dahl A. R. 
Published: February 2005

AbstractThe observation of high levels of xenobiotic metabolizing enzyme activity in the olfactory mucosa has produced speculation on the functional significance of these enzymes in the nose. Hypothesized roles include protection of the nasal epithelium, lung, and other downstream tissues, and termination or modification of olfactory responses. The enzyme rhodanese metabolizes cyanide, which is a commonly inhaled toxicant and an odorant and therefore of interest to both toxicologists and olfactory neurobiologists. The cellular localization of this enzyme within the olfactory mucosa will have important consequences for its ability to protect specific cells, as well as its ability to alter the concentration of inhaled cyanide at receptors, and therefore could provide clues as to its function in this tissue. We have compared the distribution of this enzyme in two species, the rat and the cow, using immunohistochemical localization techniques employing species‐specific polyclonal antisera raised in our laboratory. In the rat, rhodanese‐like immunoreactivity was greatest within the apical portion of the sustentacular cells, the basal cells, and the duct cells of Bowman's glands. Very little to no reaction was observed in the acinar cells of Bowman's glands. In the cow, however, the acinar cells and duct cells of Bowman's glands showed intense immunoreactivity with little to no reaction observed in the sustentacular or basal cells. The differences in localization of rhodanese in these two species may have important implications for cell types at risk during inhalation of cyanide or organonitrile compounds metabolized to cyanide within the nasal mucosa. In addition, the difference in distribution in the two species emphasizes the importance of considering enzyme activity and localization in the determination of an appropriate animal model for study of both nasal toxicology and olfactory responsiveness in humans.
Immunocytochemistry of paraneurons in the female urethra of the horse, cattle, sheep, and pig
Authors: Vittoria Alfredo , Cocca Tiziana , La Mura Elena , Cecio Aldo 
Published: February 2005

AbstractThe aim of this study is to describe the presence of neuroendocrine (NE) cells (paraneurons), producing biogenic amines and/or peptidergic hormones, in the female urethra of cattle, sheep, pigs, and horses, by means of histochemical and double labeling immunofluorescent techniques. 5‐Hydroxytryptamine‐, chromogranin A‐, cholecystokinin‐ and somatostatin‐containing NE cells are present in the urethral epithelium of all the species studied, with the unique exception of the lack of somatostatin cells in the horse. Paraneurons containing 5‐hydroxytryptamine colocalized with chromogranin A or cholecytokinin were also found in all subjects. Such active substances are hypothesized to play a role in the contraction of the urethral musculature, emission of urogenital fluids, and inhibition of endocrine and exocrine secretions. © 1992 Wiley‐Liss, Inc.