bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparative histochemical study of prosimian primate hindlimb muscles. I. Muscle fiber types
Authors: Sickles Dale W. , Pinkstaff Carlin A. 
Published: February 2005

AbstractThe profiles of fiber types in hindlimb muscles from the tree shrew (Tupaia glis), lesser bushbaby (Galago senegalensis), and the slow loris (Nycticebus coucang) were determined using histochemical techniques. Fibers were classified as fast‐twitch oxidative‐glycolytic (FOG), fast‐twitch glycolytic (FG), slow‐twitch oxidative (SO), or fast‐twitch oxidative (FO) according to reactions for alkaline‐stable ATPase, acid‐stable ATPase, á‐glucan phosphorylase, reduced nicotinamide adenine dinucleotide diaphorase, succinate dehydrogenase, mitochondrial á‐glycerophosphate dehydrogenase (MáGPDH), and ß‐hydroxybutyric dehydrogenase, as well as glycogen staining by the periodic acid‐Schiff technique. Prolonged dissection of numerous muscles was carried out on hindlimbs submersed in cold Tyrode's solution; such treatment had no qualitative effect on enzyme staining reactions, but it is not a suitable procedure if one wishes to stain for glycogen. Fast‐twitch oxidative (FO) fibers were seen only rarely, and only in tree‐shrew hindlimb muscles; these fibers are alkaline‐stable ATPase‐positive and possess low MáGPDH enzyme activity. These fibers have not been reported previously in any hindlimb muscles. No muscles of any species studied were homogeneous with respect to fiber type. Slow loris muscles lacked FG fibers. The majority of the muscles of the slow loris contained numerous SO fibers. The relationship between enzyme activities and locomotor pattern is discussed.
Characterization of seasonal changes in prolactin and growth hormone cells in the hypophyses of white‐tailed deer (Odocoileus virginianus borealis) by ultrastructural and immunocytochemical techniques
Authors: Schulte B. A. , Seal U. S. , Plotka E. D. , Verme L. J. , Ozoga J. J. , Parsons J. A. 
Published: February 2005

AbstractProlactin and GH cells were identified in thin sections taken from the adenohypophyses of adult male (6) and female (8) white‐tailed deer, collected during all seasons of the year, by locating portions of the same cells in adjacent thick plastic sections immunostained for either PRL or GH. Growth hormone cells were round to ovoid in shape and filled with dense spherical secretory granules which ranged in size from 168 to 682 nm, with a mean diameter of 367 ± 18 nm (x̄ ± SD) in the 14 glands studied. No apparent seasonal changes were evident in the ultrastructural appearance of GH cells. Prolactin cells were small and angular in shape during the winter months and contained only a few small secretory granules. By early summer, they were markedly hypertrophied, round to oval in shape, and densely packed with large spherical secretory granules. The increase in size of PRL secretory granules was most prominent in pregnant females in May, when their mean diameter was approximately double that seen in midwinter. The ultrastructural appearance of PRL cells in September was similar to that of cells studied in March. The size distribution of PRL secretory granules overlapped that of the GH granules, ranging from 114 to 564 nm, and the mean diameter was 246 ± 53 nm, calculated from all 14 individual glands. Our observations suggest that the synthesis and secretion of PRL are closely linked to photoperiodic changes in this species, and they demonstrate the necessity of using specific immunocytochemical techniques in the ultrastructural identification of pituitary acidophils, and of specifying the time of year and location (species photoperiod) in studies concerning PRL physiology, particularly when dealing with wild animal populations.
Comparative histochemical study of alimentary tracts with special reference to the mucous neck cells of the stomach
Authors: Suganuma Tatsuo , Katsuyama Tsutomu , Tsukahara Masanori , Tatematsu Masae , Sakakura Yasunori , Murata Fusayoshi 
Published: February 2005

AbstractCombinations of recently developed paradoxical concanavalin‐A staining (PCS) and other routine histochemical procedures have made it possible to classify mucosubstances more precisely. By taking advantage of these sequences, the present study was undertaken both to characterize the mucinous contents of alimentary tracts of several animal species, and to compare the variability of epithelial mucosubstances with special reference to the mucous neck cells of the stomach. The alimentary tracts obtained from 7 species of fish, 5 amphibians, 3 reptiles, 4 birds, and 6 mammals were used. Acidity of epithelial mucosubstances was highly variable even among the corresponding mucous cells. On the contrary, concanavalin‐A reactivity seemed to be consistent with each cell and species. The mucous neck cells, which were observed in amphibians, reptiles, and mammals, consistently exhibited a characteristic mucosubstance with stable class‐III reactivity by PCS. Inversely, stable class‐III reactivity was found only in species possessing mucous neck cells, and was widely distributed in the esophageal glands of the frog, snake, and man; in esophageal mucous cells of the frog and skink; in pyloric glands of amphibia, reptiles, and mammals; and in Brunner's glands of mammals. These mucous cells seem to form an unique group with morphological and histochemical similarities. It is likely that the stable class‐III reactivity by PCS is a hallmark of the mucous neck cells and related glands and that, in addition, concanavalin‐A reactivity of mucosubstances is evolutionarily more fundamental characteristic.
Kinetic analysis of epithelial cell migration in the mouse descending colon
Authors: Tsubouchi S. 
Published: February 2005

AbstractThe kinetics of epithelial cell replacement in the descending colon of the mouse were studied using cell counts and other measurements in mice given a single injection of 3H‐thymidine at 10:00 a.m. Cell migration occurs from the base of the crypts in the direction of the colonic lumen. The mean turnover time of epithelial cells as measured after the single injection of 3H‐thymidine has been estimated at 4.85 days. Since this figure is in agreement with published data based on continuous infusion of the labeled precursor, it is concluded that the time selected for the analysis provides an index of proliferation which is representative of the mean proliferative activity of the epithelium.If each side of a crypt cut along its axis is referred to as a “crypt column,” the mean number of cells per crypt column has been found to be 32.9; after a one‐hour pulse labeling starting at 10:00 a.m., the mean number of labeled cells per column was 2.8; and the overall labeling index of the epithelium, 8.6%. The frequency of labeled cells in each cell position along the crypt column varies according to a Poisson distribution with a peak close to position 3. Presumably then, cell proliferation is taking place in a random manner and is, therefore, asynchronous, despite evidence to the contrary in the literature.The kinetic analysis supports the view that cell migration occurs along the crypt column in the direction of the colonic lumen at a velocity averaging 0.28 cell position per hour, or 4.48 μm per hour.The results support the view that vacuolated‐columnar, mucous, and caveolated cells migrate jointly; whereas entero‐endocrine cells migrate separately from these cell lines, except during the initial stages of the migration.
Cell types within the medial forebrain bundle: A golgi study of preoptic and hypothalamic neurons in the rat
Authors: McMullen Nathaniel T. , Almli C. Robert 
Published: February 2005

AbstractThe morphology of lateral preoptic (POL) and lateral hypothalamic (HLA) neurons was studied in 14‐ to 200‐day‐old rats with the chlorate‐formaldehyde modification of the Golgi method. Drawings of 91 POL and HLA neurons revealed three distinct neuronal types within the MFB based on somatic size and shape and dendritic morphology. Class I neurons, which accounted for 75–80% of the neurons in the MFB, had fusiform or multipolar somata averaging 21 × 14 μm and 2–5 sparsely branched dendrites with a moderate number of sticklike spines. The extensive dendritic domains of Class I neurons ranged from 700 to 1,500 μm and were usually oriented perpendicular to the longitudinal fibers of the MFB. Both nonoriented and oriented Class I neurons were encountered. Nonoriented Class I neurons had expansive dendritic arbors which reached nearly all regions of the MFB in the coronal plane. Oriented Class I neurons had dendritic domains which were confined to specific regions (e.g., ventral‐lateral) of the MFB. Class II neurons, which made up approximately 10% of the MFB neurons, had large multipolar somata averaging 30 × 17 μm and 2–5 stout dendrites which were densely covered with hairlike spines. Class II neurons also exhibited spines on their somata and proximal dendritic trunks and had dendritic domains of 700–1,000 μm. Class III neurons had small somata averaging 15 × 12 μm and restricted dendritic arbors of 500–700 μm in diameter. Class III neurons exhibited both spiny and spine‐free dendrites and made up 10% of MFB neurons. Because of the parcellation of chemically coded fiber systems within the MFB, individual POL and HLA neurons may not be homogeneous in the type of afferents they receive from other brain areas.
Glycoprotein synthesis in the mucous cells of the vascularly perfused rat stomach. III. Mucous cells of the antrum and the duodenal glands
Authors: Smits H. L. , Kramer M. F. 
Published: February 2005

AbstractLabeled leucine, serine, galactose, glucosamine, fucose, and sulfate were administered to rat stomachs in a vasular perfusion system. Sections of gastric fundus and antrum, and of the duodenal glands, were studied by light microscopic autoradiography. The rate of incorporation of radioactive label in the various mucous cell types of the antrum and of the duodenal glands was measured by counting the silver grains over each cell type and comparing this rate with that of the surface mucous cells of the fundus. The following major observations were made: The patterns of incorporation in the mucous cells on the surface and in the pits of the antrum did not differ essentially from those of the surface mucous cells of the fundus. On the contrary, the incorporation patterns of the surface mucous cells of the fundus differed considerably from those of the mucous cells of the antral glands and from the mucous cells of the duodenal glands. The mucous cells of the antral glands showed a lower incorporation rate of amino acids and of (amino) sugars, especially of galactose and glucosamine, but a higher incorporation rate of sulfate. The mucous cells of the duodenal glands showed a considerably higher rate of incorporation for serine, but a lower rate for glucosamine. No differences were seen for leucine, galactose, and sulfate. The relatively low synthetic activity of the mucous cells of antral glands correlates well with the various amounts of RER, Golgi system, and secretory granules, found in these cells, and with the histochemical staining characteristics of their mucous granules. The mucous cells of the duodenal glands are characterized by typical parallel arrays of their numerous RER cisternae and by a low number of small secretory granules.
Osteoclast formation in vitro from bone marrow mononuclear cells in osteoclast‐free bone
Authors: Ko Jea Seung , Bernard George W. 
Published: February 2005

AbstractRecent evidence points to the fact that osteoclasts are derived from mononuclear cells of hematopoietic bone marrow. In this study we have examined the formation of osteoclasts from mononuclear cells in vitro. The mononuclear cells were isolated after 7 days from cultures of mouse bone marrow cells. The isolated cells were co‐cultured with osteoclast‐free, fetal‐mouse calvaria. After 10 to 14 days of co‐culture, multinucleated cells which have all the characteristics of osteoclasts were found in juxtaposition to seams of woven bone. These data strongly suggest that bone marrow mononuclear cells, when suitably induced, can give rise to osteoclasts in vitro.
Fluoride stimulation of the rat parathyroid gland: An ultrastructural study
Authors: Ream Larry J. , Principato Robert 
Published: February 2005

AbstractThe parathyroid glands of rats given 150 ppm fluoride in the drinking water for 10 weeks are evaluated ultrastructurally and compared to the parathyroid glands of untreated rats. As a result of fluoride ingestion, the majority of the parathyroid cells are dark chief cells, indicating that these cells are in the active stages of the secretory cycle. More significantly, in the fluoride‐treated rats, the cytoplasmic organelles of the dark chief cells are even more developed that those seen in the dark chief cells of untreated rats. The dark cells contain an electron‐dense cytoplasm with abundant lamellar arrays of rough endoplasmic reticulum, spiral aggregations of free ribosomes, multiple dilated Golgi complexes, and increased numbers of secretory granules. The cells are at a minimum dimension with maximum tortuosity of the plasma membranes; and, as a result, large intercellular spaces are often seen between contiguous cells. Based on these observations, it is suggested that, in the fluoride‐treated rat, a type of secondary hyperparathyroidism develops resulting in an increase in the organelles involved in protein synthesis and secretion.
Lens regeneration from the pupillary margin of the eyecup in newt embryos
Authors: Reyer Randall W. 
Published: February 2005

AbstractEarly stages in lens regeneration from the dorsal margin of the pupil, following removal of the young lens from the embryonic eyecup, were studied with transmission electron microscopy in Notophthalmus viridescens. At the stage of operation, the eyecup cells have an undifferentiated, embryonic appearance with numerous free ribosomes and scattered mitochondria. In normal embryonic eyes containing a lens, the iris epithelium differentiates from the edge of the optic cup by growth and flattening of the cells to form a two‐layered cuboidal epithelium. There is extensive melanogenesis in both inner and outer layers. In lentectomized eyes, this flattening does not occur and melanogenesis takes place mainly in the outer layer of epithelium. Mitoses are abundant and a vesicle of unpigmented columnar cells, enclosed by a basal lamina, develops from the dorsal pupillary margin of the eyecup. Macrophages are present and phagocytize some of the melanin but less than during dedifferentiation of pigmented iris epithelium. During this regeneration of a lens vesicle, there is an increase in the number of polyribosomes, granular endoplasmic reticulum, and mitochondria in preparation for synthesis of the lens proteins. Micropinocytosis occurs at the cell surfaces.
Distribution and identity of the earliest proliferating progeny of colony‐forming cells in regenerating murine spleen and bone marrow
Authors: Wolf Norman , Rosse Cornelius 
Published: February 2005

AbstractA study was made of the sites of development and the types of cells found in very early hemopietic colomes in the mouse spleen. Two, 3, and 4 days after transplantation, the proliferating descendants of transplanted bone‐marrow cells were identified on radioautographs of spleen sections and on spleen and bone‐marrow smears of supralethally irradiated recipient mice which were injected with 3H‐TdR at 12, 6, and 0.5 hours before sacrifice. Surprisingly the spleens of nontransplanted, irradiated mice contained proliferating medium and large lymphocytes in the white pulp which increased in numbers during the observation period. The early descendants of transplanted cells that lodged in the spleen could be clearly distinguished from the labeled indigenous cells because they formed discrete nodules or colonies beneath the splenic capsule or in the vicinity of venules and trabeculae of the red pulp. These cells were identifiable on day 2 as transitional cells or unknown hemopoietic blasts and on day 4 included early erythroid cells and small lymphocytes. There was evidence for the traffic of 3H‐TdR‐labeled cells through the splenic sinusoids.
The fine structure of the developing pelvic fin dermal skeleton in the trout Salmo gairdneri
Authors: Géraudie Jacqueline , Landis William J. 
Published: February 2005

AbstractThe morphogenetic and ultrastructural features of the dermal skeleton in the pelvic fin bud of a teleost, the rainbow trout Salmo gairdneri, have been examined by light and electron microscopy. The principal structural components observed are lepidotrichia and actinotrichia. Lepidotrichia consist of two parallel and symmetrical bony demirays that form jointed segments within the fin. The demirays calcify in a proximodistal direction within the extracellular collagen network of the basal lamella belonging to the epidermal‐dermal interface of the fin. Needle‐ and plate‐like particles of a solid mineral phase appear to be associated with the collagen fibrils and with a fine, granular, interfibrillar material central to the demirays. Cellular processes and membrane‐bound vesicles are absent from the regions of calcification. During fin growth, the bony, acellular lepidotrichia are separated from the epidermal‐dermal interface by infiltrating mesen‐chymal cells in proximal fin regions; in distal areas, the lepidotrichia remain within the basal lamella. The actinotrichia are extensive unmineralized rods of elastoidin that occupy the distal margin of the fin and precede the differentiation of lepidotrichia. Once the lepidotrichia form, actinotrichia lie preferentially between their demirays. In some instances, structural interactions are suggested between actinotrichia and lepidotrichia. Considerations of embryologic and structural features of fin components fail to support the hypothesis that individual segments of lepidotrichia are modified scales in all fish.
Age‐related changes in pineal “synaptic” ribbon populations in rats exposed to continuous light or darkness
Authors: King Thomas S. , Dougherty William J. 
Published: February 2005

Abstract“Synaptic” ribbon (SR) populations in the rat pineal gland were analyzed morphometrically at various ages from birth to early adulthood. The rats were born and raised in continuous light or continuous darkness. SR numbers were high irrespective of the presence or absence of light during the early neonatal period. However, SR numbers decreased substantially during the second neonatal week of continuous light, remaining low at subsequent ages, including early adulthood. In contrast, SR numbers apparently remained elevated during continuous darkness at various ages from the early neonatal period to early adulthood. Stimulation of pineal adrenergic receptors with L‐isoproterenol during continuous light resulted in an acute, reversible increase in SR numbers; blockade of these receptors with L‐propranolol during continuous darkness resulted in an acute decrease in SR numbers. These results indicate that light‐mediated changes in SR populations were (1) age related and (2) related to some component of the pineal beta‐adrenergic receptor mechanism. A hypothesis that SR formation may be related to beta‐adrenergic receptor‐associated membrane turnover is presented.
The pelvic epithelium of the rat kidney: A scanning and transmission electron microscopic study
Authors: Verani Regina , Bulger Ruth Ellen 
Published: February 2005

AbstractThe renal pelvis of the rat is characterized by extensions called specialized fornices that penetrate into the outer zone of the outer medulla (a type II as classified by Pfeiffer, 1968, 1970). The renal pelvic epithelium, therefore, covers areas of the kidney from the inner medulla, the inner and outer stripe of the outer medulla, and the cortex.The renal pelves of seven rats were studied by transmission and scanning electron microscopy. The transitional epithelium on the nonparenchymal surface of the pelvis was three to four cell layers thick (zone 0–1). This epithelium became thinner where it covered the renal cortex (zone 1–2) or the outer medulla. Although the apical cells of the epithelium retained the asymmetric luminal unit‐membrane plaques, the number of cytoplasmic fusiform vesicles decreased as one studied the epithelium progressing over the zones from cortex toward papilla. Scanning electron microscopy demonstrated a small number of surface cells of a different morphology that were characterized by apical microvilli. The number of these microvillous lining cells increased as the epithelium covering the outer (zone 2–3) and inner (zone 3–4) stripe regions of the outer medulla was viewed, until the inner medulla was entirely covered by this cell type. In a reciprocal manner, the cells with the asymmetric apical plaques decreased in numbers and in their morphologic specialization in each successive region. The epithelium surrounding the inner medulla (zone 6–7) was completely devoid of this transitional cell type. Judging from the morphologic characteristics of the epithelia, one could surmise that little exchange of urea, water, and salts would occur with the extrarenal connective tissue or the cortical parenchyma. Recycling of urea might become more important physiologically with the outer stripe parenchyma, and even more so with the increased surfaces of the inner stripe parenchyma that lined the secondary pyramid, as well as with the epithelium lining the inner medulla.
Physical, biologic, and phenotypic properties of natural regulatory cells in murine bone marrow
Authors: Dorshkind Kenneth , Rosse Cornelius 
Published: February 2005

AbstractA lymphocyte‐enriched fraction of murine bone marrow (BML) contains natural regulatory cells (NRC) that can inhibit, on a dose‐dependent basis, proliferative and cytotoxic responses to alloantigens in a mixed lymphocyte culture. The objective of this study was to investigate the characteristics of the cells responsible for this phenomenon in CBA mice. Maximal suppression was obtained with BML cells themselves rather than cell products. Light‐scatter analysis of NRC on the fluorescence‐activated cell sorter demonstrated them to be larger than small lymphocytes, and their sedimentation in discontinuous Percoll gradients showed the cells to be of heterogeneous density. This heterogeneity is further reflected by the fact that both plastic adherent and nonadherent BML are suppressive. NRC must be viable in order to mediate suppression; they are cortisone‐resistant and are not affected by doses of gamma irradiation up to 1,000 R. NRC are not T or B lymphocytes or Ia‐bearing macrophages. The involvement of mature granulocytes and macrophages in natural suppression is unlikely in that NRC do not bear Fc receptors. Elimination of cells from BML with the natural killer (NK) surface marker Asialo GM1 does not abrogate suppression. NRC are capable of mediating suppression across major and minor histocompatibility complex barriers. While lymphoid cells are prominent in BML, the contamination of this marrow fraction with immature granulocytes and monocytes makes a morphologic identification of NRC difficult. These characteristics are most consistent with NRC begin immature marrow cells of undetermined lineage. The relationship of NRC to naturally occurring marrow suppressor cells described in other systems is not yet clear and awaits experimental clarification.