bluuebunny/crossref_metadata_2025_split huggingface dataset:
SEM of the proximal tubule of the adult rabbit kidney
Authors: Evan Andrew P. , Hay Don A. , Dail William G. 
Published: February 2005

AbstractThe present study utilizes the scanning electron microscope (SEM) to reveal the surface morphology of proximal tubular cells and the parietal cells of Bowman's capsule of the adult rabbit nephron. To facilitate the examination of the basal surface of these cells, proximal tubules were dissected free and treated with collagenase to remove the basememt membrane. Other blocks of tissue were cryofractured to expose the lateral cell surfaces of the proximal tubules. Our investigation has shown that the lateral and basal surfaces of both the convoluted and straight segments of the proximal tubule have numerous processes. However, the arrangement and degree of branching is distinctly different in the two segments. The convoluted segment has large lateral ridges which form at the base of the microvilli and fan out to divide into lateral‐basal processes. Many of the lateral‐basal processes reach the basement membrane intact, interdigitating with complementary processes from adjacent cells. However, some of the lateral‐basal processes branch into short, knobby projections (basal villi) which may also reach the basement membrane. Patches of basal villi are interspersed between broad regions of interdigitating lateralbasal processes. Therefore, in the convoluted segment, the lateral‐basal processes form the major part of the basal cell surface. In tubular cells of the pars recta, unlike convoluted tubular cells, the majority of the ridges remain unbranched and pass directly to the basal surface where they divide into elaborate basal villi. Thus the basal surface of the pars recta cells is highly complex, appearing leaf‐like, being a composite of numerous basal villi with a few lateral ridges.The basal surface of some parietal cells of Bowman's capsule have parallel ridges, which results in patches of striations.
Site of lodination in rat mammary gland
Authors: Strum Judy M. 
Published: February 2005

AbstractThe ability of the mammary gland to take up and organically bind radioiodide was studied in non‐pregnant, pregnant, and lactating rats. Autoradiography was used to determine whether duct cells or alveolar cells are responsible for iodination in the rat mammary gland. Iodination was not detected in mammary glands from non‐pregnant rats, but occurred late in the twelfth day of gestation and continued throughout pregnancy and lactation. Protein‐containing vacuoles in alveolar cells and casein‐like proteins in milk were the major sites where iodination occurred within the gland. Milk proteins in the lumens of ductules adjacent to alveoli were also iodinated. In contrast, ducts, myoepithelial cells, fat cells, blood vessels and other histological components of the gland did not show iodinating capability. Cytochemistry was also used to identify endogenous mammary peroxidase activity in the same glands, and it was found that the presence and location of this enzyme was correlated with the ability to iodinate.
Calcium transport and the secretory ameloblast
Authors: Eisenmann Dale R. , Ashrafi Shahid , Neiman Abraham 
Published: February 2005

AbstractThe distribution of calcium in the enamel organ of the rat incisor was investigated using potassium pyroantimonate for ultrastructural localization of calcium. Substantial amounts of precipitate occurred in the intercellular compartment of the enamel organ and modest deposits were observed in specific organelles of the secretory ameloblast. Mitochondria, nuclei, granular endoplasmic reticulum, Golgi vesicles and secretory granules consistently contained small deposits of pyroantimonate. Complexing of calcium by the pyroantimonate was confirmed by EGTA decalcification and scanning electron microscope energy dispersive X‐ray analysis. The observed distribution is discussed in light of potential for an intercellular pathway of calcium transport as well as controlled movement of the ion along the synthetic and secretory route followed by organic components of enamel.
Intramitochondrial rod‐like inclusions in human breast tumors
Authors: Seman Gabriel , Gallager Harry S. 
Published: February 2005

AbstractUltrastructural screening of human breast tumor biopsies has revealed, in 43% of the carcinomas, and in 16% of the benign lesions examined, the presence of rod‐like inclusions in mitochondria of epithelial cells. The inclusions are cylindrical in cross section, with a diameter of about 50 nm, and show regular striations in longitudinal sections. They are probably derived from cristae. Mitochondria with inclusions are usually enlarged and are found most frequently in epithelial cells of invasive tumors and near zones of tumor necrosis. Similar although not identical inclusions have been observed by other investigators in the liver of women with hydatidiform mole or choriocarcinoma, of pregnant women, and of women taking oral contraceptives. Identical inclusions have been found in mitochondria of HeLa cells treated with anti‐HeLa serum. Although no clear‐cut correlations were found between the finding of inclusions and parameters such as age of patients, nuclear grade or lymphocytic infiltration of the breast tumors, it is conceivable that the presence of mitochondrial inclusions reflects the effect of hormonal or of immunological factors.
Muscle proteins and the changes in shape of avian oxynticopeptic cells in relation to secretion
Authors: Vial J. D. , Garrido J. , Dabike M. , Koenig C. 
Published: February 2005

AbstractA combined ultrastructural and biochemical study of the avian oxynticopeptic cell was performed. Scanning electron microscopy demonstrates that this cell undergoes great changes in the shape of its apical pole in relation to secretory activity. These changes are confirmed by transmission electron microscopy and by freeze‐fracture images. The biochemical finding of actin‐ and myosin‐like proteins in high‐speed supernatants of homogenates of these cells as well as the ultrastructural and cytochemical localization of actin‐like filaments in their apical poles suggest a possible participation of these proteins in the above‐mentioned changes. Thus, the study of cytoplasmic matrix elements and of their organization may be highly relevant in the search for a correlation between structure and function in these cells.
Development of T and B cell areas in peripheral lymphoid organs of the rat
Authors: Eikelenboom P. , Levenbach Muriel G. E. , van den Brink H. R. , Streefkerk J. G. 
Published: February 2005

AbstractIn the present study the early development of peripheral lymphoid organs (spleen, popliteal lymph node, mesenteric lymph node and Peyer's patches) is described in terms of homing patterns of T and B cells, demonstrated with immunohistoperoxidatic detection of characteristic membrane antigen in normal rats and with routine histology in neonatally thymectomized rats. In the first days after birth the peripheral lymphoid organs are almost exclusively populated by T cells. After neonatal thymectomy lymphocytes appear in the dome areas of Peyer's patches from four to six days after birth, in mesenteric and popliteal lymph nodes lymphocytes are found in the outer cortex from day 6 and day 8 respectively and in the marginal zone of the spleen from eight days onwards. These lymphocytes showed no membrane staining when reacted for T antigen with immunohistoperoxidatic techniques.The morphological evidence for considering Peyer's patches of rats as central inductive sites for the generation of B cells is poor. The discrepancy in the order of appearance of T and B cell (sub)populations in spleen compartments in normal ontogenetic development and lethally irradiated, stem cell reconstituted animals is discussed.
The role of epithelial coliagen and proteoglycan in the initiation of osteogenesis by avian neural crest cells
Authors: Bradamante Ž. , Hall B. K. 
Published: February 2005

AbstractOsteogenesis was inhibited when mandibular processes from 3 1/2‐day‐old embryos were cultured in BUdR, LACA, α, αβ‐Dipyridyl, 4‐Methylumbelliferone, and 4‐Methylumbelliferyl‐β‐D‐glucoside or β‐D‐xyloside. Mandibular processes were then cultured in the test substances for 3 days, enzymatically separated into their epithelial and ectomesenchymal components, combined with mandibular components from untreated embryos, and either organ‐cultured or grafted to chorioallantoic membranes of host embryos. Osteogenesis was inhibited when treated epithelium, but not when treated ectomesenchyme, was present in the tissue recombinations.Analysis of the known action of these inhibitors indicates that proliferation, hydroxylation of collagen, and synthesis of proteoglycans by epithelial cells are all necessary components of this osteogenic epithelial‐ectomesenchymal interaction.
Sequential development and tissue organization in whole mouse embryos cultured from blastocyst to early somite stage
Authors: Libbus Bisharah L. , Hsu Yu‐Chih 
Published: February 2005

AbstractThe development of mouse embryos in culture from the implantation to the head‐fold stage was sequentially examined. Our goal was to compare the morphology of embryos grown in vitro to those developed in vivo, published in standard texts, and to delineate the stages involved in the process of tissue differentiation and organization. Mouse blastocysts (stage 6) were collected at 3.5 days p.c. and cultured. Attachment of the blastocysts occurred on the second day of culture (stage 8). Following the collapse of the blastocyst endoderm cells began to migrate and to encircle the inner cell mass. At 2 days in culture the embryonic and extra‐embryonic ectoderm became distinguishable and the proamniotic cavity appeared (stage 9). Egg cylinders began to project above the substrate at 2.5 days in culture (stage 10) and to progress through the stages observed in vivo. At 4 days a posterior amniotic fold began to form (stage 11) and was followed at 5 days by the formation of the chorion, the appearance of mesoderm, exocoelom, and head fold (stage 12). At 6 days in culture the embryo had differentiated longitudinally and developed an allantois, blood islands, Reichert's membrane, head process, and primitive streak. At 7 days somites as well as the neural fold and heart were observed (stage 14) and were followed by further differentiation at 8 days (stage 15). These observations indicate that apparently normal embryo development can be maintained in vitro through the early stages of organogenesis, thus providing a unique opportunity for investigating the regulation of early mammalian development.
Orderly particle arrays on the mitochondrial outer membrane in rapidly‐frozen sperm
Authors: Friend Daniel S. , Heuser John E. 
Published: February 2005

AbstractBy deep‐etching and rotary replication of unfixed, non‐cryoprotected tissue frozen on a helium‐cooled copper block, previously undemonstrable organellar surfaces and intramembranous structures can be examined. Among the more remarkable features of mammalian spermatozoa thus prepared are the highly ordered particulate arrays on the surface of the mitochondrial outer membrane. In the midpiece of the sperm, mitochondria curl around dense fibers and the axoneme. The surface of the mitochondrion that faces the plasmalemma carries closely packed rods in haphazard dispersement, composed of two to four 70‐to 80‐Å particles, <20 Å apart, while the concave aspect of the organelle contains rods in stepladder pattern. These ladders are parallel, with their paticles in neighboring rungs apparently in register at a 40–45° angle relative to the mitochondrial axis. This organizational disparity between the convex and concave surfaces of the organelle not only affords evidence of a new mitochondrial substructure, but represents a type of topographical heterogeneity rarely found except within specialized areas of the plasma membrane.Other novel findings in the sperm cell include the observation of “lipid” tracts flanking intramembranous particle‐strands in the plasmalemma of the cytoplasmic droplet, and a gridiron design on the cytoplasmic faces of the droplet's microcisternae, as well as both within and atop its plasma membrane—a motif consistent with the presence of exocytotic or endocytotic activity in this portion of the cell. Additional recent observations are the differing internal and external periodicities of axonemal microtubules and the subunit structure of rectangles on the tail surface overlying the intramembranous particles of the zipper.
Effects of immunization with Freund's complete adjuvant and isologous spermatozoa on the seminiferous epithelium and blood‐testis barrier in guinea pigs
Authors: Pelletier R.‐M. , Nemirovsky M. S. , Calvert R. , Hugon J. S. 
Published: February 2005

AbstractIn order to gain insight into the earliest pathological changes underlying the development of autoimmune aspermatogenic orchitis (AIAO) the blood‐testis barrier was studied by light and electron microscopy, freeze‐etching, and cytochemical techniques early (from 1 to 8 days after adjuvant treatment or isoimmunization). At later times (16 to 21 days) the study was carried out by light microscopy only. Adult male guinea pigs were used either as controls or immunized with Freund's complete adjuvant alone or together with pertussis vaccine. An additional group comprised animals immunized with a suspension of isologous spermatozoa emulsified in Freund's complete adjuvant and with pertussis vaccine. Ultrastructural studies of the testes of experimental animals showed, at earlier periods, apparently normal Sertoli junctions. However, in the adluminal compartment, distended gaps were seen between the facing membranes of adjacent Sertoli cells. At later periods, a massive destruction of the germinal cells were observed. In freeze‐fracture replicas, the Sertoli junctions of testes belonging to all the experimental groups were characterized by an irregular network of occasionally interrupted strands of particles associated with the P face (PF). Large concavities determined distensions between interconnecting ridges. The gap junctions were increased in number and in surface. Tracer studies using horseradish peroxidase showed that the marker permeated the myoid cells of a greater proportion of tubules than in control animals. Within the seminiferous epithelium there was only a limited passage of the marker towards the lumina of the tubules. Yet the tracer was always excluded from the adluminal compartment by the Sertoli tight junctions.Our observations suggest the possibility that the FCA causes a loosening of the Sertoli junctions. This condition could enhance exchanges between two antigenically different cellular compartments and, thus, favor occurrence of an autoimmune reaction when cytotoxic factors are experimentally induced, as in iso‐ or autoimmunization.
The ultrastructure of the avian Golgi tendon organ
Authors: Haiden Gerald J. , Awad Essam A. 
Published: February 2005

AbstractThe ultrastructure of the avian Golgi tendon organ (GTO) is described and compared with those of mammals using transverse sections through the myo‐tendinous junctions of wing muscles of adult mallard ducks.The capsule, which is continuous with the perineural epithelial sheath of the Ib afferent nerve fiber, consists of four to seven flattened cellular lamellae. Two to four muscle fibers attach to large collagen bundles which enter the GTO through a tight collar at the proximal end of the fusiform capsule. These collagen bundles divide into many smaller bundles, which run longitudinally through the lumen in compartments formed by septal cells. The septal cells contain many prominent lipid accumulations. The Ib axon divides several times, and the unmyelinated branch axons weave between the small collagen bundles. Schwann cell processes or basement membrane usually intervene between the axons and collagen bundles. The small collagen bundles regroup into larger bundles, which pass through tight capsular collars and merge with the main muscle tendon. The size of the duck GTOs was measured and found to be smaller than the GTOs of man, cat or rat.
Submandibular glands in mice with muscular dystrophy: Studies with nerve growth factor
Authors: Murphy Richard A. , Watson Ann Y. , McCarthy Mary , Papastavros Mary , Neutra Marian , Forssmann W. George 
Published: February 2005

AbstractExperiments have been carried out to examine the submandibular glands in mice with hereditary muscular dystrophy. Radioimmunoassay data confirm biological studies which show that submandibular glands in mice with muscular dystrophy contain less nerve growth factor (NGF) than glands of normal animals. Male dystrophics have half as much submandibular NGF as unafflicted mice, while females have only 10% of control levels. Gel filtration and electrophoretic studies detect no differences in the molecular properties of NGF in gland extracts from normal and dystrophic mice. Furthermore, NGF from both sources show equal activity in the sensory ganglion bioassay. Together, these results suggest that NGF deficits in submandibular glands of dystrophic mice are not due to measurement artifacts arising from alterations in the structure of the molecule.Morphological studies have uncovered a cytological basis for chemical deficits within submandibular glands of dystrophic mice. Stereological analysis of light and electron microscopic sections revealed that growth factor containing granular tubule cells (GTC) take up a smaller portion of the total gland volume, are smaller in size, and contain fewer secretory granules than comparable cells in glands from controls. Furthermore, the ultrastructure of GTC in dystrophic animals suggests that the cells are less active in producing secretory protein than GTC in glands from normal animals. These results are consistent with the idea that growth factor deficits arise from cellular abnormalities in the granular tubule segment of the gland.
A histological study of the Harderian gland of mongolian gerbils, Meriones meridianus
Authors: Sakai Tatsuo , Yohro Takeshi 
Published: February 2005

AbstractThe histological structure of the gerbil Harderian gland was investigated by means of light and transmission electron microscopy. The single excretory duct of the gland is directly continuous with endpieces at the hilus and opens nasally and ventrally to the third eyelid. The excretory duct is accompanied by many acini of small serous glands around it. The gland is composed of tubuloalveoli (tubular alveoli) with wide lumina and is not divided into lobules. There is no branched duct system within the gland. The tubuloalveoli themselves convey the secretory materials to the hilus where the excretory duct begins. The alveolar epithelium is composed of only one type of glandular cell as well as myoepithelial cells. The glandular cells contain many clear secretory vacuoles containing lipids and well‐developed tubular smooth endoplasmic reticulum. The secretory vacuoles are surrounded by a unit membrane and are secreted by exocytosis. The interstices of the gland contain two types of autonomic nerve varicosities and a number of melanocytes. The surface of the gland is covered with the endothelium of the orbital venous sinus.
Morphological changes in the mechanically unloaded myocardial cell
Authors: Tomanek Robert J. , Cooper George 
Published: February 2005

AbstractThe role of stretch and/or tension in maintaining the structural integrity of the myocardial cell was investigated in 16 cats. Right ventricular papillary muscles were studied 1–28 days after transection of the chordae tendinae and compared to adjacent intact papillary muscles. A progressive atrophy, as shown by decreased mean cell cross‐sectional area, occurred; by the 28th day mean cardiocyte area was only 28% of the control value. The earliest ultrastructural changes (one day after surgery) were primarily focal and included disorientation of contractile filaments and loss of Z‐line substance. During the first week, vacuolation, loss of contractile filaments, and infiltration of macrophages and fibroblasts were characteristic. By the second week a massive loss of contractile substance, disappearance of the sarcoplasmic reticulum, and a marked increase in connective tissue occurred. Leptomere structures, membrane alterations, and phagocytosis were the most typical changes between the second and fourth week. Hydroxyproline assays on papillary muscles unloaded for three days showed a 38% increase in connective tissue, indicating an early increase in connective tissue/muscle mass associated with mechanical unloading.It is concluded that the cardiocyte is extremely dependent upon mechanical loading, i.e., stretch and/or tension. Mechanical unloading (tenotomy) results in rapid and marked cellular degeneration which exceeds that observed in skeletal muscle following either disuse or denervation.
Ontogeny of caudal fourth ventricular tanycytes in the rabbit brain: A Golgi study
Authors: Felten David L. , Cummings John P. , Burnett Bruce T. 
Published: February 2005

AbstractA Golgi study of the floor of the caudal fourth ventricle in the developing and adult rabbit brain stem revealed the presence of several clusters of tanycytes. These tanycytes possessed ciliated apical surfaces and basal shafts extending into the substance of the medulla and pons where they intermingled with specific neuronal fields. These shafts ended in the serotonergic nuclei raphe obscurus and pallidus, and the noradrenergic locus coeruleus and nucleus intercalatus (group A2). The tanycyte shafts extended into the medullary midline early in ontogeny (day 18 of gestation), following which the neurons of the raphe began to sprout neurites. These shafts then formed the underlying structure for a large medullary dendrite bundle. These shafts developed extensive spines during early neonatal ontogeny, which then diminished in number through adulthood. The tanycyte shafts extending into locus coeruleus and nucleus intercalatus developed later in ontogeny than the midline shafts, just before birth. These shafts also persisted into adulthood in close relationship with the monoamine neurons. We suggest that the tanycytes on the floor of the fourth ventricle may take up substances from the CSF and transport them to the region of the monoamine nuclei where the shafts terminate, in a manner similar to median eminence tanycytes. The early development of shafts from fourth ventricular tanycytes suggests a possible regulatory role for these cells over the neuritic sprouting and maturation of the monoaminergic nuclei.
Membranous systems in the “chloride cell” of teleostean fish gill; their modifications in response to the salinity of the environment
Authors: Pisam M. 
Published: February 2005

AbstractThe membranous systems of the “chloride cell” were studied in teleostean fish gills stained in ferrocyanide‐reduced osmium (Karnovsky, '71). Three distinct systems were observed: (1) the tubular system, densely stained with ferrocyanide‐reduced osmium, was made up of anastomosed tubules opening in the latero basal intercellular space; (2) the endoplasmic reticulum, faintly stained, and continuous with the nuclear envelope; (3) the vesiculotubular system, the staining of which was intermediate between those of both previously cited systems, was made up of vesicles and short tubules. These membranous systems underwent modifications according to the salinity of the exterior medium: (1) the tubular system formed a broad and loose network in fresh water adapted fishes; in salt water, the meshes of the network became small, tight, and regular thus increasing the cell surface area. (2) the endoplasmic reticulum, which in fresh water, consisted of dilated cisternae often studded with ribosomes; in salt water, it developed in a network of anastomosed smooth sheets interdigitated with the tubular system. (3) the vesiculotubular system seems to be also more developed in salt water than in fresh water‐adapted fishes.