bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pathological changes in cerebral arteries following experimental subarachnoid hemorrhage: Role of blood platelets
Authors: Clower Ben R. , Yoshioka Junji , Honma Yutaka , Smith Robert R. 
Published: February 2005

AbstractThe role of blood platelets in producing early intimal changes in cerebral arteries following subarachnoid hemorrhage (SAH) was examined by using 18 cats. Experimental SAH was produced by a rupture of the proximal portion of the right middle cerebral artery. Following SAH, the scanning electron microscope revealed that structural alterations in the intimal layer of major cerebral arteries occurred as early as 2 hours and became more severe by 48 hours. Vascular alterations, which were predominantly detected in the ruptured vessel, consisted of endothelial cell corrugation, detachment, crater formation, intimal adhesion of platelets and red blood cells, intimal thrombi, and reendothelialization. When cats were pretreated prior to SAH with an anti‐platelet‐aggregating agent, OKY‐1581, the intimal blood elements and thrombi were clearly reduced, and reendothelialization was not observed. However, endothelial cell changes in the OKY‐1581‐treated group were very similar to those occurring in the nontreated group. While these results suggest that bioactive substances contained within blood platelets, such as growth factors, serotonin, and norepinephrine, have little effect on producing endothelial cell injury, platelets may be important in the initiation of reendothelialization following vessel injury.
Surface coat material associated with the developing otic placode/vesicle in the chick
Authors: Sinning Allan R. , Olson Mark D. 
Published: February 2005

AbstractSurface coat material (SCM) has been illustrated in association with the apical surfaces of numerous epithelia during morphogenesis. This study investigates the development of a SCM associated with the invaginating otic placode/vesicle in the chick. Glycoconjugate containing SCM was retained by the inclusion of cetylpyridinium chloride (CPC) in the fixative, histochemically visualized by using ruthenium red (RR) staining, and viewed by scanning (SEM) or transmission (TEM) electron microscopy. Initial characterization of the glycoconjugates present in this material was elucidated by using lectins conjugated to fluorescein isothiocyanate. Lectins utilized included concanavalin A (Con A), wheat germ agglutinin (WGA), and soybean agglutinin (SBA). Invagination of the otic placode was apparent as early as stage 12. By stage 15 the vesicle was beginning to separate from the surface ectoderm as evidenced by its aperture, which was altered in shape and reduced in size. All embryos fixed with glutaraldehyde containing either CPC or RR were shown to possess SCM associated with the surface ectoderm, particularly in the area of the otic placode/vesicle. Additional embryos were processed by cryofixation without prior alehyde fixation; these also exhibited SCM. All lectins labelled the epithelium of the otic placode/vesicle. However, their binding patterns were not identical. The binding of Con A and WGA remained constant over the stages studied, while SBA increased as the otic vesicle developed. The data clearly indicate that otic placode morphogenesis is accompanied by the synthesis of SCM rich in glycoconjugates.
Lectin binding to the human retina
Authors: Söderström Karl‐Ove 
Published: February 2005

AbstractFormalin‐fixed, paraffin‐embedded tissue sections of the human retina were stained with different fluorescein isothiocyanate‐conjugated lectins. The lectins used were concanavalin A (Con A), Triticum vulgaris (WGA), glycine maximum (SBA), Dolichos biflorus (DBA), Ulex europaeus (UEA I), Arachis hypogaea (PNA), and Ricinus communis (RCA I).Con A stained both the inner and outer segments of the rods and cones, whereas WGA stained the inner and outer segments of the rods and the outer segments of the cones. PNA selectively stained only the inner segments of the cones. In addition, Con A and WGA stained neuron cytoplasm and nerve fibers in different layers of the retina. The results obtained differ in some important aspects from those previously obtained in the frog and monkey retina; this finding may be due to species differences. The results of lectin staining in the normal human retina may form the basis for future studies of retinal diseases.
Earliest enamel deposits of the rat incisor examined by electron microscopy, electron diffraction, and electron probe microanalysis
Authors: Landis William J. , Burke Grace Y. , Neuringer Julia R. , Paine Mary C. , Nanci Antonio , Bai Paul , Warshawsky Hershey 
Published: February 2005

AbstractIn order to describe initial events in enamel mineralization and to help characterize inorganic‐organic interactions in this tissue, the earliest rod and interrod enamel in mandibular incisors from normal young adult (100 gm) rats, perfused with 100% ethylene glycol, has been studied by transmission electron microscopy, selected area electron diffraction, and high‐spatial‐resolution electron probe microanalysis. Diffraction and probe data were correlated precisely from the same extracellular regions of the tissue. Sites were examined progressively as a function of location (a) from the most recently deposited enamel adjacent to ameloblasts toward the dentin‐enamel junction and (b) from the apical portion of the tooth longitudinally toward its incisal end. Electron diffraction patterns consistent with that of a poorly crystalline hydroxyapatite were generated at all locations. Diffraction characteristics changed only slightly toward that of more crystalline hydroxyapatite at different locations. Earliest apical enamel generated molar Ca/P ratios in a range of 0.99–1.46 (average 1.24 ± 0.15). Molar Ca/P ratios of the first enamel interrod elements increased from ∼1.24 at ameloblast‐enamel boundaries to ∼1.40 at the dentin‐enamel junction, small changes corresponding to those observed in electron diffraction characteristics.
High glucose‐6‐phosphatase activity in osteoblasts in the metaphysis of femur of growing rats
Authors: Tokunaga Hirohiko , Kanamura Shinsuke , Watanabe Jun , Kanai Kazuo , Sakaida Minoru 
Published: February 2005

AbstractGlucose‐6‐phosphatase (G6Pase) activity was examined cytochemically in the metaphysis of femurs of 3− and 7‐day‐old rats. G6Pase and hexokinase activities were also examined biochemically in the femur and tibia of 3‐day‐old animals. The reaction product for G6Pase activity was seen in the endoplasmic reticulum and nuclear envelope of all cell types composing the metaphysis. The amount of the reaction product was abundant in osteoblasts, moderate in osteocytes, and moderate to scarce in osteoclasts and capillary endothelial cells. Biochemical G6Pase activity in the bones was higher than that in the brain, submandibular gland, or pancreas of the animals. Hexokinase activity in the bones was not different from that in the submandibular gland, pancreas, or kidney. The activity ratio of G6Pase and hexokinase in the bones (0.603) was greater than that in the submandibular gland, pancreas, or brain and smaller than that in the kidney. Possible physiological significances of the higher G6Pase activity in osteoblasts are discussed.
Effects of various insulin dosages on hepatic lipogenesis
Authors: Drake Richard L. 
Published: February 2005

AbstractInsulin treatment of diabetic rats fed a high‐carbohydrate, fat‐free diet produces a dramatic accumulation of hepatic lipids. However, this increase in hepatic lipids may only be a response to injections of exceptionally high doses of insulin. This study addresses this possibility. Alloxan‐diabetic rats, fed a high‐carbohydrate, fat‐free diet, were given insulin every 12 h for 60 h at the following dosages: 1/2 unit each, 1 unit each, 2 units each, and 4 units each of regular and NPH insulins. At the end of the treatment period, liver samples were collected and used for morphological and biochemical analyses. Histologic examination revealed hepatic lipid accumulations at all insulin doses; the amount of lipid increased until maximal levels were reached at an insulin dosage of 1 + 1, which was maintained at doses of 2 + 2 and 4 + 4. Thus, hepatic lipid accumulation occurs regardless of the dosage of insulin administered to the diabetic animal. It is not simply an abnormal cellular response to excessive hormone levels. Similarly, the activity of the hepatic lipogenic enzyme, malic enzyme, increased at initial insulin dosages and reached maximal levels at 2 + 2. However, in contrast to lipid accumulation, enzyme activity decreased at the final insulin dosage of 4 + 4. Thus, there appears to be a direct relationship between increasing insulin levels and malic enzyme activity until an optimal insulin concentration is reached. After this point, excessive insulin levels do inhibit malic enzyme activity.
Long‐term reiention of regenerative capability after denervation of skeletal muscle, and dependency of late differentiation on innervation
Authors: Gulati Adarsh K. 
Published: February 2005

AbstractThe present study examines the influence of denervation on the regenerative ability of skeletal muscle in rats. Muscle denervation was achieved by transecting and ligating the cut ends of the sciatic nerve. Four to 48 weeks after denervation, the extensor digitorum longus (EDL) muscle was autotransplanted to induce muscle regeneration. The transplanted EDL muscles were examined at 1–12 weeks. Normal (i.e., no prior denervation) EDL muscle autotransplants were also examined for comparison. Denervation resulted in progressive atrophy of muscle, marked by a reduction in the size of myofibers and an increase in endomysialperimysial connective tissue. In spite of these alterations, typical events of muscle regeneration were invariably observed after transplantation. Initial myofiber degeneration and subsequent regeneration of myotubes occurred in a manner similar to normal muscle transplants. However, only a partial maturation of myotubes was observed in denervated muscles. These results show that extended denervation does not abolish the capability for muscle regeneration. The precursor myosatellite cells, proposed to be responsible for muscle regeneration, retain their regenerative potential after denervation. It is concluded, however, that the presence of intact innervation is crucial for the terminal differentation and maturation of regenerating muscle.
Structure of the complex basement membrane underlying the epithelium of the vas deferens in the rat
Authors: Clermont Y. , Hermo L. 
Published: February 2005

AbstractUnderlying the epithelium of the vas deferens there is a complex basement membrane showing a thick lamina densa separated from the plasma membrane of epithelial cells by a lamina lucida. On the connective tissue side of the lamina densa, there are plaques composed of a material that is similar to that of the lamina densa but is more compact and has a greater electron density. This material also forms plaques at a short distance from the lamina densa, where it appears as irregular nodular masses. The plaques are bridged by striated anchoring fibrils (SAF) that are variable in structure. Some SAF are long (0.5–0.6 μm) and bilaterally symmetrical, with a central fusiform segment and, on each side, coarsely banded segments. While the fusiform segment presents 5 or 6 diffuse cross striations, the coarsely banded segments show distinct bands labeled B1−B4. Shorter SAF show a coarsely banded segment alone or a coarsely banded segment plus a fusiform segment. Some SAF also branch at the level of the fusiform segments, in which case they from star‐shaped structures with three or more branches that have their extremities inserted into plaques. The plaques, as well as the lamina densa, are immunohistochemically reactive to type IV collagen, laminin, and heparan sulfate proteoglycan, whereas the SAF are not immunoreactive to these substances. SAF and plaques, considered as integral components of this basement membrane, form a series of arches or open tunnels traversed by collagen fibrils. It is thus apparent that these elements contribute to the attachment of the basement membrane and the overlying epithelium to the underlying dense connective tissue of the lamina propria.
Unilateral hindpaw amputation causes bilateral articular cartilage remodeling of the rat hip joint
Authors: Joseph Threlkeld A. , Smith Stephen D. 
Published: February 2005

AbstractThe purpose of this paper was to describe the remodeling of adult coxofemoral articular cartilage (AC) in response to altered weight bearing. Twelve adult male Sprague‐Dawley rats underwent unilateral hindpaw transection at the distal tibiofibular junction (AmpCont group); another group of eight rats served as normal controls (Norm group). Subpopulations of both groups were injected with 35SO4 24 hr before harvest. All femora were harvested after 8 weeks. Safranin O stained longitudinal sections were used to determine AC thickness, cellularity, and proteoglycan (PG) staining. Regional grain counting was performed on autoradiographs. Analysis of the data revealed that the AC of Norm hips in the region near the fovea capitis femoris was significantly thicker, had a lower cell density, a greater PG density, and a lower 35SO4 incorporation rate per chondrocyte than the AC of the Norm lateral edge region. The intact limbs of the AmpCont animals demonstrated a relative thinning of the AC near the fovea capitis femoris, compared with the edge region, and reduced 35SO4 incorporation rate in the lateral edge region, compared with normal values. The operated limb of the AmpCont animals displayed a relative increase of PG density in the edge region compared with the foveal region and a reduced 35SO4 incorporation rate in the lateral edge region, compared with normal values We concluded that rat coxofemoral AC responds bilaterally to unilateral hindpaw amputation through appropriate morphologic remodeling.
Functional units in rainbow trout (Salmo gairdneri, Richardson) liver: II. The biliary system
Authors: Hampton James A. , Clark Lantz R. , Goldblatt Peter J. , Lauren Darrel J. , Hinton David E. 
Published: February 2005

AbstractThe intrahepatic biliary system was studied in the rainbow trout (Salmo gairdneri), a teleost known to form liver neoplasms after exposure to various carcinogens. Normal adults (N = 25) were examined using light microscopic, enzyme histochemical, and transmission and scanning electron microscopic methods. In light micrographs, longitudinal arrays of hepatocytes appeared as double rows incompletely divided by elongated darkly stained cells. Electron micrographs showed tubules of five to nine pyramidally shaped hepatocytes with their apices directed toward a central biliary passageway and their bases directed toward sinusoids. Sequentially, beginning with hepatocytes, biliary passageways included canaliculi, preductules, ductules, and ducts. Canaliculi were short and joined transitional passageways (preductules) formed by junctional complexes between plasma membranes of hepatocytes and small, electron‐dense cells with a high nuclear to cytoplasmic ratio. Ductules, completely lined by biliary epithelial cells, occupied central regions of hepatic tubules. Relatively elongated, ductular cells were intimately associated with surrounding hepatocytes, separated from them by only a thin extracellular space devoid of a basal lamina. Epithelium of bile ducts included cuboidal through mucus‐laden columnar cells, surrounded by basal lamina and, in larger ducts, by fibroblasts, smooth muscle cells, and a capillary plexus. Bile ducts and hepatic arterioles, but not venules, were distributed together. The ultrastructure of biliary epithelium, periductular, and periductal cells is presented.
Histochemical, immunohistochemical, and ultrastructural observations on the iris muscles of Gallus gallus
Authors: Scapolo P. A. , Peirone S. M. , Filogamo G. , Veggetti A. 
Published: February 2005

AbstractThe distribution and typology of fibers in the two muscular systems (sphincter and dilator) of the iris in Gallus gallus were determined histochemically, immunohistochemically, and ultrastructurally. The sphincter muscle in proximity to the ciliary margin was composed predominantly of slow fibers. In the intermediate tract, a large group of fast oxidative fibers were evident and the pupillary margin was exclusively composed of slow fibers. The fast‐fibers had histochemical and immunohistochemical patterns similar to the α fibers in the skeletal control muscle (biventer cervicis). In contrast, the slow fibers were composed of at least three slow types, which were comparable to the isoforms of the different myosins in β1 and β2 skeletal fibers.In the dilator muscle, the oblique system was uniquely composed of fast oxidative fibers. The radial system was predominantly composed of slow fibers with isoforms of myosins different from the slow fibers of the sphincter and control muscles.Ultrastructural features (width of Z bands, extension of the sarcoplasmic reticulum and SR‐T tubule junctions, and number of mitochondria) confirm the histochemical and immunohistochemical assessments of fiber types, even if some peculiar aspects in several fibers were observed. Smooth muscle cells separated from striated fibers were evident at the pupillary margin. The hypothesis of a mesenchymal origin for all irideal striated muscles is discussed.
Ultrastructural characteristics of sustentacular cells in control and odorant‐treated olfactory mucosae of the salamander
Authors: Zielinski Barbara S. , Getchell Marilyn L. , Getchell Thomas V. 
Published: February 2005

AbstractThe ultrastructural characteristics of five morphologically distinct regions of sustentacular cells in the salamander olfactory mucosa are described. 1) The apical region was characterized by a microvillar surface that lay below the level of the olfactory knob of olfactory receptor neurons and contained endosome‐like vesicles and a filamentous array at the level of the zonula adherens. 2) The supranuclear region contained rough and smooth endoplasmic reticulum, a Golgi complex, and secretory vesicles. Few sustentacular cells showed morphological signs of secretion, suggesting a low rate of baseline secretory activity. 3) The nuclear region contained the cylindrical nucleus surrounded by a thin band of cytoplasm containing bundles of filaments. 4) The central stalk contained filamentous arrays, Golgi‐like cisternae, multivesicular bodies, and peroxisomes. Cytoplasmic veils that extended from the central stalk contained filamentous aggregates. 5) The basilar expansion had a complex series of lateral and basal folds. The lateral folds enveloped extracellular material and nonmyelinated axons of the receptor neurons. The basal folds formed complex interdigitations with the basal lamina, particularly in regions occupied by blood vessels and the acini of Bowman's glands in the subjacent lamina propria. These characteristics, and the presence of endosome‐like vesicles and mitochondria, suggest that the basilar expansion is metabolically active and participates in cellular transport of material. Treatment with the odorant 2‐isobutyl‐3‐methoxypyrazine caused ultrastructural changes in the apical and supranuclear regions that were associated with secretion and in the basilar expansion region that were indicative of an increase in metabolic and transport activity.
H+‐K+‐ATPase activity in the rat incisor enamel organ during enamel formation
Authors: Sasaki Takahisa , Tadokoro Katsumi , Yanagisawa Takaaki , Higashi Shohei , Garant Philias R. 
Published: February 2005

AbstractThe enamel organ of growing rat incisors was perfusion‐fixed with a mixture of formaldehyde and glutaraldehyde and processed for ultracytochemical demonstration of ouabain‐resistant, K+ ‐stimulated p‐nitrophenylphosphatase representing the second dephosphoylative step of H‐K‐ATPase by use of the one‐step lead method. Throughout the stages of amelogenesis, the enzymatic activity was found in the plasma membranes, mitochondrial membranes, and lysosomal structures of the cells of stratum intermedium, papillary layer, and ameloblast layer. Gap junctions and desmosomes between these cells were, however, free of reaction product or showed slight precipitates of reaction. The stellate reticulum and the outer enamel epithelium at the stage of enamel secretion were usually negative for reaction. Although secretory, transition, and ruffle‐ended maturation ameloblasts showed enzymatic activity at their basolateral cell surfaces, their distal cell surfaces facing the enamel were always free of reaction product. On the other hand, the smooth‐ended maturation ameloblasts seldom showed a positive reaction, except in lysosomes and along their basal cell surfaces. An energy‐dispersive X‐ray microanalysis of reaction products of H‐K‐ATPase in unosmicated tissue sections demonstrated that they were composed of lead and phosphorus, which had been released during the dephosphorylation of substrate. In cytochemical controls, the enzymatic activity was completely dependent on substrate and potassium ion, resistant to ouabain and levamisole, and inhibited by nelinium bromide, a specific inhibitor of H‐K‐ATPase. In addition, inorganic trimetaphosphatase as enzymatic marker of lysosome was localized in dark and pale lysosomes, phagosomes, multivesicular bodies, and ferritin‐containing vesicles of the ameloblasts and the cells of stratum intermedium and papillary layer. These membrane‐bound structures were also positive for H‐K‐ATPase reaction. These results suggest that: 1) H‐K‐ATPase functions to maintain an acidic internal pH of lysosomes in the enamel organ cells; and 2) H‐K‐ATPase localization in the plasma membranes of enamel organ cells is concerned with efflux of protons derived from cytoplasmic water.
Survival of satellie cells in whole muscle transplants
Authors: Schulitz Edward , Albright David J. , Jaryszak Debra L. , David Tracy L. 
Published: February 2005

AbstractThe ability of satellite cells to survive the ischemic conditions at the core of orthotopically free grafted rat extensor digitorum longus muscles was examined. Cell cultures of isolated core and peripheral regions of whole muscle grafts maintained in vivo for more than 24 hours indicated that no viable cells were present in the core, whereas the number of cells from the peripheral region was greatly increased. Muscles were examined with the electron microscope to determine the fate of satellite cells of the core at various times after transplantation. The population of satellite cells in the core was reduced beginning at 18 hours and had virtually disappeared by 24–28 hours. This reduction did not appear to be the result of satellite cell death. Although there was abundant morphological evidence that myonuclei as well as myofiber cytoplasmic organelles were degenerating, there was little indication of satellite cell death in situ at any time period studied. These studies suggest that satellite cells cannot survive, but migrate from the ischemic core to more peripheral regions of whole muscle transplants. In addition, they suggest that migration is an important aspect of the regeneration response in the free graft system and permits the myogenic population to contribute en masse to the centripetal wave of regeneration from the time it is initiated at the muscle periphery.