bluuebunny/crossref_metadata_2025_split huggingface dataset:
Structural evidence for two different testicular types in teleost fishes
Authors: Grier H. J. , Linton J. R. , Leatherland J. F. , De Vlaming V. L. 
Published: February 2005

AbstractTesticular structure in Salmoniformes, Perciformes, Cypriniformes, and Atheriniformes has been examined and reinterpreted on the basis of two different tubular types, distinguished from each other by the intratubular distribution of spermatogonia. In the salmoniform, perciform, and cypriniform teleosts studied, spermatogonia are distributed along the entire length of the testicular tubules. However, in the atheriniform teleosts spermatogonia are restricted to the distal end of the tubule. Sperm development in teleosts is cystic, cysts being comprised of Sertoli‐cell processes. In both testicular types described, Sertoli cells phagocytize spermatid residual bodies. Together witb the germ cells, they comprise the only intratubular cell types within the teleostean testis.Boundary cells are located immediately outside of the tubule basement membrane. They do not form a complete layer over the tubule surface; therefore, interstitial Leydig cells and blood vessels may border directly upon the tubular basement membrane.
Serotonin and seasonal variation in the pancreatic structure of bats: Possible presence of serotonergic axons in the gland
Authors: Nunez Eladio A. , Gershon Perry , Gershon Michael D. 
Published: February 2005

AbstractThe serotonin concentration in the bat pancreas was determined at nine times during the year. Pancreatic ultrastructure was also examined. The pancreatic level of serotonin was uniform throughout the year except in late May, when it fell dramatically from a normal level of 3.14 ±.19 μgm/gm to 0.40 ± .05 μgm/gm. No seasonal changes in islet fine structure were found; however, the ultrastructure of exocrine cells was seen to be changed radically only in bats captured in late May. At this time, bats develop unusual cytoplasmic structures in the exocrine cells. These structures consist of membrane‐limited bodies containing long, straight, and parallel paracrystalline arrays of stacked membranes and round or pleomorphic osmiophilic granules. Depletion of serotonin with reserpine or parachlorophenylalanine, or incubation of pancreatic tissue with different concentrations of serotonin, failed to provoke the formation of these structures in exocrine cells of active bats. Administration of 3H‐5‐hydroxytryptophan to bats, or incubation of bat pancreas with 3H‐serotonin, failed to demonstrate a labeling of pancreatic exocrine cells. Incubation of the gland with 3H‐serotonin, however, led to intense labeling of a subset of pancreatic terminal axons. It is concluded that the natural fall in the concentration of serotonin in late May is not the cause of the formation of the paracrystalline structures in pancreatic exocrine cells. The specific pancreatic uptake mechanism for serotonin found by Kovary et al. ('80) is probably a property of pancreatic neurites; these neurites might be serotonergic.
Specific uptake of tritiated serotonin in the adult rat pancreas: Evidence for the presence of serotonergic fibers
Authors: Koevary Steven B. , McEvoy Robert C. , Azmitia Efrain C. 
Published: February 2005

AbstractFragments of adult rat pancreas were incubated in vitro with tritiated serotonin at concentrations from 10−8 to 10−7 M. The pancreas exhibited an uptake of serotonin which was saturable, with an uptake constant (Km) of 8.75 × 10−7 M, and a Vmax of 873 pmoles per gram. Specificity was determined by the addition of fluoxetine or norepinephrine to the reaction mixture, both at 10−5 M. Fluoxetine significantly reduced the 3H‐5HT uptake, whereas norepinephrine was without effect. Metergoline (10−6 M), a specific 5‐HT postsynaptic receptor blocker, similarly had no effect on the serotonin uptake in the pancreas. Radioautography of the fragments following uptake of tritiated serotonin (5 × 10−8 M) revealed silver‐ grain aggregates dispersed along blood vessels in the interstitial spaces of the exocrine and endocrine pancreas, areas known to be traversed by nerve fibers. There were no silver‐ grain aggregates over the exocrine or islet parenchymal cells. These data support the hypothesis that the pancreas is innervated by serotonergic fibers. Further evidence for this hypothesis was provided by a preliminary study demonstrating the presence of tryptophan hydroxylase in pancreatic homogenates. These serotonergic fibers may be involved in the regulation of pancreatic secretion.
Seasonal changes in prolactin and growth hormone cells in the hypophyses of white‐tailed deer (Odocoileus virginianus borealis) studied by light microscopic immunocytochemistry and radioimmunoassay
Authors: Schulte B. A. , Seal U. S. , Plotka E. D. , Verme L. J. , Ozoga J. J. , Parsons J. A. 
Published: February 2005

AbstractNumerous investigators have shown a relationship between basal serum prolactin (PRL) levels and photoperiod in domestic ungulates, and we have shown recently that a similar seasonal baseline serum PRL profile exists in both sexes of a captive but free‐breeding population of white‐tailed deer. In order to localize and describe the distribution and possible seasonal changes of PRL and growth hormone (GH) cells in the adenohypophyses of deer, we have used antisera raised against ovine PRL and bovine GH and the unlabeled antibody enzyme technique, in conjunction with point counting morphometry. In addition, we have measured seasonal changes in pituitary PRL concentrations in this same population, using a heterologous application of a recently developed homologous radioimmunoassay (RIA) for ovine PRL. Our results show that GH and PRL cells comprise two morphologically separate and immunologically distinct populations. Growth hormone cells were distributed evenly throughout the gland, except in the zona tuberalis, and males had a slightly greater volume density of immunoreactive GH than females; however, there were no differences between sexes in the average size of these cells, and little seasonal change was observed in these cell populations. In contrast to GH cells, the volume density of PRL cells, the size of PRL cells, and the pituitary concentration of RIA‐measurable PRL all showed marked seasonal changes in deer of both sexes. These changes were well correlated with one another and with previously reported changes in basal serum levels (in these animals), in that they all reached zenith during midsummer, and nadir in midwinter. Our results demonstrate the necessity of reporting the time of year and latitude (to specify photoperiod) in studies concerning PRL cell physiology, particularly when dealing with any wild animal population.
Glomerular architectural changes after a two‐hour infusion of norepinephrine
Authors: Bulger Ruth Ellen , Cronin Robert E. , Dobyan Dennis C. 
Published: February 2005

AbstractAlterations in glomerular architecture have been suggested to play a role in the pathogenesis of several models of acute renal failure. In this study, mongrel dogs were subjected to an intrarenal infusion of norepinephrine for 2 hours. Light microscopy and scanning and transmission electron microscopy were used to describe glomerular architecture 2 days after the initial norepinephrine infusion. In addition, scanning electron microscopy was used to quantitate the percentage of “abnormal areas” in glomerular capillary‐loop morphology in both norepinephrine‐infused kidneys and the contralateral control kidneys. Alterations in glomerular structure in these experiments appeared to be much less extensive than previously reported. A variable amount of glomerular pedical shape simplification was seen, which involved about 15% of the capillary loop Quantitative evaluation revealed abnormal morphology of 15.2% ± 0.6% of the glomerular capillary loop in the norepinephrine‐infused kidneys, compared to 2.9% ± 0.4 abnormal loop structure in the contralateral control kidneys (P <0.001). It is concluded that alterations in glomerular structure are not extensive in this model.
Coiled bodies in supraoptic nuclei of the rat hypothalamus during the postnatal period
Authors: Hervas J. P. , Villegas J. , Crespo D. , Lafarga M. 
Published: February 2005

AbstractIn electron microscopic studies of the supraoptic nuclei of the rat hypothalamus, structures identified as “coiled bodies” were found in magnocellular neurons. Although they could be seen elsewhere in mature neurosecretory cells, coiled bodies were commonly encountered in developing neurons during the postnatal period in both sexes. They appeared as distinctive nuclear inclusions consisting of round‐to‐oval networks of short electron‐dense strands embedded in a less dense, fibrillar matrix, and lacking a limiting membrane. In fine structure and stain‐affinity, they bore a resemblance to the fibrillar component of the nucleolus.Coiled bodies were located either in close association with the nucleolus or free within the nucleoplasm, showing no specific relationships with the perinucleolar chromatin or with the nuclear envelope. Their origin and functional meaning is discussed in the light of recent ultrastructural and biochemical data on cellular differentiation and nucleolar behavior.
Osteogenesis and leukopoiesis within diffusion‐chamber implants of isolated bone marrow subpopulations
Authors: Budenz Richard W. , Bernard George W. 
Published: February 2005

AbstractThe developmental potential of isolated rabbit bone marrow cell populations was examined following autogeneous implantation into diffusion chambers. After 4 weeks, tbe implants were harvested and processed for light and electron microscopy. More total tissue was formed in abdominally implanted chambers than in corresponding femoral chambers. Two of the separated marrow cell populations produced significantly greater amounts of fibrous connective tissue, cartilage, and bone than did whole‐marrow controls. These two populations, which were defined by density gradients of 1.050–1.055 gm/cm3 and 1.064–1.067 gm/cm3, consistently produced a fibrous connective tissue nodule in which were found dispersed foci of hyaline cartilage and woven bone. The denser population was distinguished further by the presence of leukopoietic foci in several of the implant chambers. Cartilage foci were found predominantly towards the center of the tissue nodules, whereas bone was dominant towards the periphery. Blood vessels, osteoclasts, bone remodeling, and mature lamellar bone were found only in those chambers which had been penetrated by the host's vascular system. The results indicate that (1) normal marrow tissue contains two separate osteoprogenitor cell populations; (2) these two progenitor populations represent separate osteogenic and chondrogenic capabilities; (3) one of these populations possesses a leukopoietic as well as an osteogenic potential; and (4) a competent vascular system is essential for the remodelling of bone into mature bone organs.
Modes of protein and peptide uptake in the pineal gland of the Mongolian gerbil: An ultrastructural study
Authors: Welsh Marcia G. , Beitz Alvin J. 
Published: February 2005

AbstractThe possible existence of either a blood‐brain barrier or a CSF‐brain barrier was examined in the pineal gland of the Mongolian gerbil using the ultrastructural tracers, horseradish peroxidase (HRP) and microperoxidase (MP). The mechanism of protein and peptide transport within the pineal gland and its possible relationship to pineal concretions was also considered. Gerbils were injected with either MP or HRP intravenously (IV), or they received intraventricular (IVT) injections of HRP. The IV injections resulted in both MP and HRP movement through the endothelial cells of the gland by vesicular transport and by diffusion through the endothelial intercellular junctions. Following the IVT injections, the tracer was demonstrated in the subarachnoid space as well as in the glial cells associated with the periphery of the gland. In addition, after the IVT injections, rounded enlargements of the intercellular space that resembled canaliculi were filled with reaction product. In both cases (IVT and IV), the reaction product was localized to the perivascular space, to the glial cells and pinealocytes, and to the intercellular spaces. More importantly, there was specific localization of the tracers in the vacuolated pinealocytes and in the pineal concretions. The results of this study demonstrate several significant findings: (1) neither a blood‐brain barrier nor a CSF‐brain barrier exists in the pineal gland of the gerbil, (2) localization of the tracers in pineal concretions indicates a relationship between these structures and protein and peptide storage within the gland, and (3) the presence of the tracers within canaliculi after the IVT injections suggests a possible mode of secretion of pineal substances into the CSF.
Structure of the tight junctions of the human eccrine sweat gland
Authors: Briggman J. V. , Bank H. L. , Bigelow J. B. , Graves J. S. , Spicer S. S. 
Published: February 2005

AbstractThe human eccrine sweat gland contains two anatomically and functionally discrete segments: the secretory coil, which produces an isotonic or slightly hypertonic precursor fluid, and the coiled duct, which resorbs Na+ and Cl− to yield a hypotonic sweat. We examined the freeze‐fracture morphology of tight junctions from isolated secretory coil and coiled duct segments to assess indirectly the contribution of paracellular ion transport in secretion and resorption in the sweat gland. In the secretory coil, tight junctions of the intercellular canaliculus and main lumen consisted of approximately 9 and 6, closely spaced, parallel or anastomosing elements, respectively. Tight junctions of the coiled duct were similar in appearance to those at the main lumen of the secretory coil. In both the secretory coil and coiled duct, and average of 2 to 3, widely spaced junctional elements were usually observed basolateral to the closely spaced junctional elements in the region corresponding to the location of the zonula adherens in Epon sections. The complexity of the tight junctions of the secretory coil exceeded what we expected for an epithelium secreting an isosmotic fluid. The elaborate tight junctions of the coiled duct support other evidence for an intermediate to high transepithelial resistance.
Ultrastructure of decidualization in the pseudopregnant rat
Authors: O'shea Jeremy D. , Kleinfeld Ruth G. , Morrow Henry A. 
Published: February 2005

AbstractThe ultrastructure of the endometrial stroma in rats bearing deciduomata was examined in detail on day 9 (day of vaginal cornification = day 0) of pseudopregnancy, together with the development of deciduomata from day 4 to day 8. Five major regions were recognizable on day 9. (1) In the basal zone, which contributes to endometrial regeneration following decidualization, stromal cells remained fibrocyte‐like and were separated by wide bands of collagen fibrils. Capillaries were fenestrated and large. (2) The capsule surrounding the antimesometrial (region of the) deciduoma was composed of flattened cells, showing mitosis, which appeared to provide a source of appositional growth of the deciduoma. (3) The large, tightly packed, polyploid cells of the antimesometrial deciduoma showed morphological evidence of protein synthetic activity, an absence of smooth endoplasmic reticulum, and surface specializations suggestive of adhesion (adherens junctions), communication (gap junctions), and maintenance of an extensive surface area (lamellar processes). These cells came into very close apposition with capillary endothelial cells, which were seldom fenestrated, lacked any continuous basal lamina, and showed evidence of high metabolic activity. (4) The loosely packed mesometrial deciduoma contained a structurally supportive, “fixed” population of spiny cells and a “free” population of granulated cells and their putative precursors, together with a meshwork of large, sinusoidal capillaries whose endothelium was generally supported by a basal lamina. (5) The peripheral parts of the glycogenic area, which was structurally similar to the mesometrial deciduoma, contained many grossly enlarged intercellular spaces of undetermined function. The stromal cells at day 4, which give rise to all non‐vascular elements except the granulated cells mentioned above, were structurally simple and fibrocyte‐like. Only two distinct regions, subepithelial and deep, were recognizable. Capillaries at day 4 generally possessed a continuous endothelium, with a complete basal lamina and many pericytes. Between days 5 and 8, the stromal cells showed divergent forms of differentiation according to their position in the endometrium. Ultrastructural differentiation of the vasculature also showed divergence according to position, leading to the various types of capillaries seen at day 9. Regional variation, and high levels of structural organization, characterize the “programed” decidual response in the pseudopregnant rat.
Morphology of taste buds on the gill arches of the mullet Mugil cephalus, and the killifish Fundulus heteroclitus
Authors: Hossler Fred E. , Merchant Lynn Harris 
Published: February 2005

AbstractThe morphology of taste buds on the gill arches of two euryhaline teleosts, the mullet Mugil cephalus, and the killifish Fundulus heteroclitus, were investigated using light microscopic and scanning and transmission electron microscopic techniques. On the mullet gill arches, taste buds were limited to the pharyngeal surfaces of the smooth‐surfaced gill rakers. On the killifish gill arches, taste buds were located on the pharyngeal surfaces of all gill rakers and on the gill arch itself at the bases of the gill rakers. Despite dramatic differences in gill‐raker structure between these two species, the taste buds themselves were similar ultrastructurally and closely resembled those described in other fishes. Cells within the taste buds included spindle‐shaped dark and light cells and basal cells. Ultrastructural features of both the light and dark cells could support either receptor or transport functions. Tufts of microvilli, including one thick microvillus per light cell and numerous thin microvilli per dark cell, protruded at the apex of each taste bud between the ridged surface epithelial cells. Light cells contained numerous tubular membrane elements some of which appeared to open onto the apical surface of the taste bud. Dark cells contained numerous microtubules and apical, electron‐lucent vesicles possibly involved in transport.
The afferent connections of the inferior olivary complex in rats: A study using the retrograde transport of horseradish peroxidase
Authors: Swenson Rand S. , Castro Anthony J. 
Published: February 2005

AbstractRetrograde transport of horseradish peroxidase (HRP) was used to define the origin of afferents to the inferior olivary complex (IOC) in rats. Using both ventral and dorsal surgical approaches to the brainstem, HRP was injected into the IOC through a micropipette affixed to the tip of a 1‐μl Hamilton syringe. After a 2‐day postoperative survival, animals were sacrificed by transcardiac perfusion with a 1% paraformaldehyde‐1.25% gluteraldehyde solution, and brains were processed according to the DeOlmos protocol (1977), using o‐dianisidine as the chromogen.Labeled cells were found at many levels of the nervous system extending from lumbar spinal cord to cerebral cortex. This wide‐ranging input from numerous regions clearly underscores the complexity of the IOC and its apparent involvement in several functions.Within the spinal cord, labeled neurons were identified from cervical to lumbar but not at sacral levels. These neurons were found contralaterally in the neck region of the dorsal horn and in the medial portions of the intermediate gray.In the caudal brainstem, reactive cells in the dorsal column nuclei, the spinal trigeminal nucleus, and the subnucleus y of the vestibular complex were observed primarily contralateral to the injection sites. Labeling within the gigantocellular, magnocellular, ventral, and lateral reticular nuclei and the nucleus prepositus hypoglossi was primarily ipsilateral. Reactive neurons in the medial and inferior vestibular nuclei were predominantly ipsilateral or contralateral to HRP injections into the caudal or rostral IOC, respectively.The dentate and interposed nuclei of the cerebellum contained small, lightly labeled neurons primarily contralateral to the injection site, while the fastigial nuclei contained a few relatively large, heavily labeled cells bilateral to caudal olivary injections.Ipsilaterally labeled mesencephalic regions included the periaqueductal gray, interstitial nucleus of Cajal, rostromedial red nucleus, ventral tegmental area, medial terminal nucleus of the accessory optic tract, nucleus of the optic tract, and the lateral deep mesencephalic nucleus. The caudal part of the pretectum and small cells of the stratum profundum of the superior colliculus were labeled predominantly contralateral to the injection.In the caudal diencephalon labeled neurons were most numerous within the nucleus of Darkschewitsch and the subparafascicular nucleus, primarily ipsilateral to olivary injections. Scattered reactive neurons were also found within the ipsilateral zone incerta. With the exception of the zona incerta, all labeled mesencephalic and diencephalic nuclei had some bilateral representation of labeled cells.No labeled neurons were identified within the basal ganglia, while numerous reactive cells were found bilaterally within layer V of the frontal and parietal cerebral cortex.
Studies on the organization and regeneration of bone marrow: Origin, growth, and differentiation of endocloned hematopoietic colonies
Authors: Lambertsen Richard H. , Weiss Leon 
Published: February 2005

AbstractHematopoietic colonies were studied by light microscopy in the marrow of alternate fraction x‐irradiated mice (C576J/B1) to investigate the microenvironmental organization of marrow and identify early hematopoietic cellstromal cell interactions. Undifferentiated colonies (UC) were detected at 3 days postirradiation, showed a marked predilection for bone surfaces, and disappeared as differentiated colonies developed. Some UC occurred along marrow arteries. Neutrophilic granulocyte colonies (GC) occurred in all areas at 3 days but grew rapidly only subosteally. Few eosinophilic colonies (GCe) occurred. Erythrocytic colonies (EC) appeared at 4 days as dispersed populations of motile cells within a localized area of marrow; these tended to proliferate initially in intermediate and central marrow zones. Macrophage colonies (MϕC) of two “subtypes” were detected, peaking in relative frequency at 4 days. These appeared active in stromal repair and monocytopoiesis. Megakaryocyte colonies (MC) originated along bone and differentiated away from bone. From 3–5 days, the frequency of GC > UC > MϕC ≫ MC ≅ GCe. All colony types except UC, MϕC, and central GC increased in size and became mixed in differentiation by 12–14 days. For several weeks, however, erythropoiesis concentrated toward central areas, whereas granulopoiesis and thrombopoiesis concentrated along bone. Some mixed colonies showed an abrupt transition from erythrocytic, centrally, to granulocytic, subosteally. These results were interpreted as evidence that in x‐irradiated marrow: (1) hematopoietic microenvironments (HMs) for stem‐cell proliferation and commitment to differentiation, with the possible exception of HMs determining erythroid differentiation, occur in endosteal and periarterial regions; (2) a proliferative and/or chemotactic stimulus to erythroid progenitors exists in intermediate and central marrow regions; and (3) some subosteal regions may exclude erythropoiesis, or preferentially support nonerythroid differentiation. Elaborate associations occurred between macrophages and early UC, GC, and EC, but not MC hematopoietic cells. UC and GC often associated with osteoclasts. Reticular and other fibroblastic cells associated with the cells of all colony types.