bluuebunny/crossref_metadata_2025_split huggingface dataset:
Porcine colonic lymphoglandular complex: Distribution, structure, and epithelium
Authors: Morfitt David C. , Pohlenz Joachim F. L. 
Published: February 2005

AbstractLymphoepithelium and cells specialized for uptake and transport of foreign matter are characteristic of antigen sampling organs, Including lymphoglandular complexes (LGCs). Distribution, his‐tologic structure, and epithelial ultrastructure of co‐Ionic lymphoglandular complexes were determined in 5‐ to 13‐week‐old pigs. LGCs averaged 1,231 in number per colon, displayed a characteristic distribution pattern, and were most evenly distributed in colons of older pigs. LGCs consisted of well‐defined submucosal masses composed of lymphatic nodules and internodu‐lar lymphoid tissue penetrated by radially branching extensions of mucosal glands. Epithelial diverticula of each LGC entered the submucosa as a group through a circular collar derived from the muscularis mucosae. LGC epithelium contained goblet cells, cuboidal and columnar enterocytes, enteroendocrine cells, individual and clustered intraepithelial leukocytes, and cells morphologically compatible with follicle‐associated epithelial cells/M cells. We regard the colonic LGC as a distinct mucosal lymphoid organ and suggest a significant role for it in local and systemic immune responses. The porcine colonic LGC may serve as a model for the human LGC.
Formation of secretion granules in the Golgi apparatus of plasma cells in the rat
Authors: Rambourg A. , Clermont Y. , Hermo L. , Chrétien M. 
Published: February 2005

AbstractThe three‐dimensional structure of the components of the Golgi apparatus was analyzed in plasma cells of rat duodenum. The spheroidal juxtanu‐clear Golgi apparatus was formed by a continuous rib‐bonlike structure composed of the following stacked elements. On the cis‐face of the Golgi stack, there was a tubular membranous network referred to as the cis‐element and/or a slightly dilated saccule perforated with small pores. The two or three subjacent saccules, which showed few pores, were slightly dilated and contained a fluffy granulofilamentous material. They were also perforated in register by cavities or wells containing 80‐nm vesicles. The next one or two underlying elements were fenestrated saccules showing flattened portions as well as distended portions containing a homogeneous material denser than that seen in the overlying saccules. The last two or three elements of the stack showed a partially separated or “peeling off” configuration. These last elements consisted of prosecretory granules attached to flattened, empty‐looking saccules showing buds at their surface; detached, more‐or‐less fenestrated, flattened saccules; and shrivelled residual trans‐tubular networks. In the trans‐region of the stack, in addition to numerous small vesicles, short membranous tubules, detached prosecretory granules, and denser fully formed secretion granules were also seen. These images were interpreted to indicate that secretory material present in the trans‐saccules flows toward the dilated portions which become prosecretory granules. The trans‐most elements seemingly peel off the stack to yield prosecretory granules and fragmenting trans‐tubular networks.
Septal collateralization: Demonstration of canine intramyocardial collaterals
Authors: Wilson Jack L. , Scheel Konrad W. 
Published: February 2005

AbstractThe anatomical distribution of intra‐myocardial collateral arteries that develop from the septal to the other major coronary arteries was studied in dogs following gradual Ameroid occlusion of tftt circumflex artery. The septal artery was cannulated and injected with Batson's plastic compound resulting in a cast of the coronary circulation. Collateral vessels radiated from the septal vascular bed to both the circumflex and anterior descending arteries. The collaterals developed from the entire base‐to‐apex extent of the septal artery and were found on both the right and left sides of the septum. Collateral growth appeared to be more concentrated at the apex of the heart. The anatomical details of septal collateral circulation illustrate the importance of intramyocardial collateralization in the dog, which was thought to exhibit primarily epicar‐dial collaterals.
Immunocytochemical localization and biochemical analysis of α and β keratins in the avian lingual epithelium
Authors: Carver Wayne E. , Sawyer Roger H. 
Published: February 2005

AbstractThe α and β keratins are found as 10‐nm and 3‐nm cytoplasmic filaments, respectively. While the a keratins are produced in essentially all vertebrate epithelia (Franke et al.: Exp. Cell Res., 116:429‐445, 1978; Sun et ah: Proc. Natl. Acad. Set. USA, 76:2813–2817, 1979), the β keratins have been demonstrated only in specific epithelial tissues of birds and reptiles (Sawyer et ah: In: Biology of the Integument: Vertebrates. J. Bereiter‐Hahn, A.G. Matoltsy, and K, S. Richards, eds. Springer‐Verlag, Berlin, Vol. 2, pp. 194–238,1986; Land‐mann: In: Biology of the Integument: Vertebrates. J. Bereiter‐Hahn, A.G. Matoltsy, and K.S. Richards, eds. Springer‐Verlag, Berlin, Vol. 2, pp. 150–187, 1986). Recently, Homberger and Brush (Zoomorphology, 106:103‐114, 1986) have demonstrated that within the lingual epithelium of parrots, β keratins are expressed exclusively in the anterior ventral region. While it is well established that epidermal‐dermal interactions are important for the regional expression of the β keratin genes in the avian scutate scales and feathers, little is known about the expression of β keratins in other epithelial structures such as the tongue. We have used biochemical and immunocytochemical techniques to analyze the a and β keratins of the lingual epithelium of the chick as an initial step in the characterization of this model system for developmental studies. We have found that α keratins are present throughout the lingual epithelium. The anterior ventral epithelium contains α keratin polypeptides characteristic of skin‐type differentiation, while the epithelium of the dorsal and posterior ventral regions contains α keratin polypeptides characteristic of esophageal‐type differentiation (O'Guin et al.: In: Current Topics in Developmental Biology: The Molecular and Developmental Biology of Keratins. A.A. Moscona and A. Monroy, eds. R.H. Sawyer, vol. ed. Academic Press, New York, Vol. 22, pp. 282–306, 1987). Beta keratins are produced only in the differentiated epithelial cells of the anterior ventral region of the tongue. Immunoelectron microscopy demonstrates that the α and β keratins of the stratum intermedium and corneum of the anterior ventral region are found together in the large filament bundles characteristic of this region. The preexistence of the α keratins in the cells destined to produce β keratins as well as the colocalization of these keratins in the filament bundles of these cells suggests that a functional relationship may exist between the α. and β keratins.
Lectin histochemistry of the embryonic heart: Fucose‐specific lectin binding sites in developing rats and chicks
Authors: Fazel A. R. , Sumida H. , Schulte B. A. , Thompson R. P. 
Published: February 2005

AbstractGlycoconjugates, particularly their sugar side chains, play important roles in embryonic development. Changes in cell‐surface‐associated glyco‐conjugates are known to affect cell differentiation, cellular interactions, and other developmental phenomena during embryogenesis. The embryonic heart goes through a series of complicated morphologic events during development. Of particular interest is morphogenesis of the outflow tract. This region of the embryonic heart originates from more than one cell population and undergoes a complex process of septation during formation of the great vessels. Histochemi‐cal analysis with a series of fucose‐specific lectins conjugated to horseradish peroxidase has revealed the presence of a fucosylated glycoconjugate in the outflow tract of the developing heart. The results reveal further that the expression of the fucosylated glycoconjugate is stage‐dependent and thus probably genetically regulated. The timing and distribution of staining with the lectin OFA suggest that this fucosylated glycocoiyu‐gate may play a role in directing the migration of neural crest cells into the heart and subsequent formation of the conus septum.
Three methods for producing fertile hemopoietic chimeras in mice
Authors: Johnson Sigrid R. , Lala Peeyush K. 
Published: February 2005

AbstractThree methods for producing semiallogeneic (F1→parental) hemopoietic chimeras with retained or regained fertility are detailed here. Prenatal (PN) chimeras were produced by injecting F1 ([BALB/c ♀ × C3H/HeJ♂] or [CBA/J♂ × C57BL/6♂]) fetal liver (days 13–18) or adult bone marrow cells (106–107 cells/20 μl/embryo) into the yolk‐sac cavities of days 13–17 gestation BALB/c or CBA/J embryos, respectively, and allowing them to be born naturally. Neonatal (NN) chimeras were made by introducing F1 bone marrow cells (1–2 × 107 cells/0.25 ml) into newborn (< 24 hr old) female mice through the anterior facial vein. Female mice were raised to maturity in both cases. Ovary‐transplanted (OT) chimeras were made by first irradiating (9.5 Gy) and repopulating young female adult mice with 107 F1 bone marrow cells, followed by bilateral orthotopic transplantation of syngeneic ovarian tissue six weeks later. Females reconstituted with the above three methods were mated with normal syngeneic males and sacrificed at 11–16 days of pregnancy to evaluate hemopoietic chimerism. This was determined in all cases by a radioautographic evaluation of the extent of donor H‐2 phenotype marker expression on splenic small lymphocytes, after an indirect labelling of single‐cell suspensions with monospecific antibody and [125I]protein‐A. Results indicate that hemopoietic chimerism was best in the PN group (0.3–78.1%, mean = 27.1); intermediate in the OT group (5.8–38.2%, mean = 18.1); and low in the NN group (0–14%, with one exception, which was 83.6%). Observed fertility was best for BALB/c host PN chimeras. Decreased litter size was observed in CBA/J host chimeras of both the PN and NN groups. OT chimeras showed a decreased capacity to become pregnant as well as lowered litter sizes. These data suggest that the prenatal chimera system offers the best method for obtaining both good hemopoietic chimerism and excellent fertility in experimental mice for future studies in reproductive biology and hematology.
Hemopoietic origin of certain decidual cell precursors in murine pregnancy
Authors: Johnson Sigrid R. , Graham Charles H. , Lysiak Jeffrey J. , Lala Peeyush K. 
Published: February 2005

AbstractThe possible hemopoietic origin of certain precursors of uterine decidual cells appearing during normal murine pregnancy was investigated in semiallogeneic hemopoietic chimeras with retained or regained fertility. Chimeras were produced by three different methods in two donor‐host combinations: F1 [BALB/c ♀ × C3H/HeJ ♂] cells introduced into the parental strain BALB/c ♀ hosts or F1[CBA/J ♀ × C57BL/6 ♂] cells introduced into CBA/J ♀ hosts. Prenatal chimeras (PN) were made by reconstituting mouse fetuses (day 13–17) with 106–107 adult bone marrow or fetal liver cells through the yolk sac and they were allowed to be delivered naturally. Neonatal chimeras (NN) were made by injecting 1–2 × 107 adult bone marrow cells into the anterior facial vein of neonatal mice (< 24 hr old). In both cases, experimental animals were raised to maturity. Ovary‐transplanted chimeras (OT) were made by injecting 107 bone marrow cells into lethally irradiated (9.5 Gy) young adult female mice, followed 6 weeks later with bilateral orthotopic transplants of syngeneic ovary grafts to restore fertility. All female chimeras produced by the three different methods were mated with syngeneic male partners to produce normal pregnancy. The extent of chimerism at the cellular level was determined in all cases by a radioautographic identification of the H‐2 phenotype of splenic lymphocytes and decidual cells and macrophages in the collagenase‐dispersed decidua at day 11–16 of normal pregnancy, following a sandwich labelling with monospecific anti‐H‐2 antibodies and 125I– protein A. Morphological discrimination of typical decidual cells from macrophages in the collagenase‐dispersed decidua was carried out on the basis of several distinctive markers: presence of surface Dec‐1 and Thy‐1 and absence of surface F4/80 or latex phagocytosis for decidual cells, in contrast to macrophages which were phagocytic and expressed F4/80 but not Dec‐1 or Thy‐1. While the degree of hemopoietic chimerism (judged by the incidence of donor‐derived lymphocytes in the spleen) varied from animal to animal, in all three groups (PN, NN, and OT) comprising a total of 26 chimeras, the percentage of typical decidual cells expressing donor H‐2 phenotype showed an excellent correlation with that for small lymphocytes in the spleen. These results reveal that at least a sub‐population of typical decidual cells of the pregnant uterus has a hemopoietic genealogy. A possible familial relationship of these cells to granulated metrial gland cells remains unclear.
Contours and distribution of sites that react with antiacetylcholinesterase in chicken intrafusal fibers
Authors: Maier Alfred 
Published: February 2005

AbstractSerial cross and longitudinal sections of intrafusal fibers from the intracapsular portions of chicken tibialis anterior muscle spindles were incubated with a monoclonal antibody specific for chicken acetylcholinesterase (AchE) and examined by immunofluorescence for the presence of the enzyme on presynaptic and postsynaptic membranes of neuromuscular junctions. The midequatorial sensory region which lacks organized sarcomeres was negative, but immediately distal to it faintly staining regions of AchE localization were observed on intrafusal fibers. In cross sections at the juxtaequator, the outlines of areas that were positive for AchE were either thin and crescentlike or thick and compact. The distribution of both types of localization continued into the polar region. Toward the more distal polar region, the intensity of sites on the postsynaptic membrane that reacted with the anti‐AchE progressively increased. In longitudinal sections, AchE localization was largely limited to two configurations. One was elongate, while the other was more round or oval and often also smaller. Both types might occur on the same, or on different, intrafusal fibers. Examination of silver‐impregnated sections revealed the presence of platelike and of traillike axon terminals. The variety of shapes observed on presynaptic and postsynaptic membranes warrants further study to determine whether chicken muscle spindles are innervated by more than one type of motor neuron.
Mapping gold‐labeled receptors on cell surfaces by backscattered electron imaging and digital image analysis: Studies of the IgE receptor on mast cells
Authors: Stump R. F. , Pfeiffer J. R. , Schneebeck M. C. , Seagrave J. C. , Oliver J. M. 
Published: February 2005

AbstractThe response of cells to signalling molecules such as hormones, growth factors, and immune mediators that bind to cell‐surface receptors depends in part on the density and distribution of the relevant receptors. We have developed methods to map the distribution of IgE receptors on RBL‐2H3 mast cells at high resolution in the scanning electron microscope (SEM). The key elements of our procedure are a new fixative that preserves receptor binding activity; a family of colloidal gold‐conjugated probes that bind directly or indirectly to the IgE‐receptor complex; an SEM with detectors for both secondary and backscattered electrons (to observe surface topography and gold particles, respectively); and an image processor that can average, digitize, and store these images. Topographical maps are generated by processing and superimposing the digitized images. The methods we describe can be applied to study the density and distribution of any membrane receptor that can be labeled with colloidal gold particles.
Topographical and planar distribution of Helix pomatia lectin‐binding glycoconjugates in secretory granules and plasma membrane of pancreatic exocrine acinar cells of the rat: Demonstration of membrane heterogeneity
Authors: Kan Frederick W. K. , Bendayan Moïse 
Published: February 2005

AbstractThe lectin‐gold technique was used to detect Helix pomatia lectin (HPL) binding sites directly on thin sections of rat pancreas embedded in Lowicryl K4M and on freeze‐fracture preparations of rat pancreas submitted to fracture label. On thin sections of acinar cells, whereas the content of zymogen granules was negative or weakly labeled, the limiting membrane displayed a high degree of labeling. In the Golgi complex, labeling by HPL was localized on the trans saccules and the limiting membrane of the condensing vacuoles. The latter appeared to be more intensely labeled than the membrane of the zymogen granules. Intense labeling by HPL was also observed along the microvilli and the plasma membrane. In contrast to the weak labeling of the zymogen‐granule content, labeling of the acinar lumen was intense. Fracture‐label preparations revealed preferential partition of HPL‐binding sites to the exoplasmic half of the zymogen‐granule and plasma membranes. The population of zymogen granules was, however, heterogeneous with respect to labeling intensity; the exoplasmic fracture‐face of the plasma membrane was intensely and uniformly labeled, while the protoplasmic membrane halves were only weakly labeled. These observations were further confirmed and extended by the thin‐section fracture‐label approach. In addition, favorable profiles of thin sections of freeze‐fractured zymogen granules showed that the labeling was not associated with the external surface of the limiting membrane, but rather localized over the exoplasmic fracture‐face. We conclude that (1) zymogen granules contain little HPL‐binding glycoconjugates, (2) HPL‐binding sites are preferentially associated with the exoplasmic half of the zymogen‐granule and plasma membranes, and (3) the limiting membrane of the immature condensing vacuoles carries a greater number of HPL‐binding sites than that of the mature zymogen granules. These last, in turn, constitute a heterogenous population with respect to labeling density. These results support the current view that glycoconjugates are directed toward the lumen in secretory granules but become external to the cell surface after fusion of the secretory‐granule membrane with the plasma membrane. Also, the results reflect membrane modifications during the maturation process of secretory granules in the exocrine pancreas in which glycoproteins are removed from the limiting membrane of the granule to become soluble and secreted with the content.
Immunogold detection of glycoprotein antigens in sea urchin embryos
Authors: Benson Nancy C. , Benson Stephen C. , Wilt Fred 
Published: February 2005

AbstractFour developmental stages of sea urchin embryos were labeled with colloidal gold in an attempt to elucidate the intracellular trafficking patterns within the cells that produce the glycoprotein matrix of the embryonic spicule. The primary mesenchyme cells (PMCs) form a syncytium and secrete an organic matrix on which calcium carbonate is laid down to form an endoskeletal spicule. The organic matrix has been isolated and characterized as glycoprotein consisting of four major bands. Polyclonal antibodies to these glycoproteins were used to label embryos from the mesenchyme blastula, early gastrula, late gastrula, and plutei stages of development. The label is concentrated in the Golgi complex and associated vesicles, in secretory vesicles, and in the organic matrix. The density of the labeling increases as development proceeds.
Detection of gold probes with video‐enhanced contrast microscopy: Nanovid microscopy
Authors: De Brabander M. , Geerts H. , Nuydens R. , Nuyens R. 
Published: February 2005

AbstractThis contribution describes a new microscopic technique aimed at visualizing colloidal gold particles of 20‐40 nm diameter as dynamic markers at the light microscopic level. The technique, called nanovid microscopy, is based on the use of contrast enhancement by video techniques and digital image processing. Two applications on living cells are discussed. The first is the receptor‐mediated endocytosis of the transferrin receptor, which for the first time can be followed in real time. A second application documents the motion of cell‐surface glycoproteins on PTK2‐cells.In addition, nanovid microscopy allows the number of gold particles in immunogold staining to be quantified easily. With this tool, the translocation of specific molecules in living cells becomes one of the most enjoyable activities to observe.
Gold labeling of cell monolayers grown on dextran beads
Authors: Hogan M. E. , Hassouna H. I. , Klomparens K. L. 
Published: February 2005

AbstractGold labeling of antigenic sites has become an increasingly useful tool in the study of cultured cell monolayers. If these mono‐layers are grown on flat substrates, major difficulties in both scanning (SEM) and transmission electron microscopy (TEM) specimen preparation and imaging may result. An alternate surface, that of dextran microcarrier beads, eliminates a majority of these difficulties and facilitates correlative TEM and SEM.The SEM procedure for using backscattered electron imaging requires the use of carbon planchets as the cell growth matrix to eliminate background signals. These planchets are expensive and are not an optimal cell‐attachment matrix in that they result in loose and abnormally shaped cells. In contrast, the dextran beads were produced specifically for cell culture and, therefore, provide an excellent surface for growth. The beads have an average diameter of 100 μm, allowing attachment directly to aluminum stubs without signal generation from the aluminum to interfere with the gold signal.With TEM preparation, the monolayer poses the major disadvantage. Specimen preparation for thin sectioning is often preceded by extensive manipulation. In the microcarrier bead system, the beads are directly sectionable, and it is possible to cut five to eight full beads per thin section. This increase in cell surface makes quantification of gold labeling easier and also provides a more representative sampling of the monolayer.The ease of preparation, the decrease in reagents used (via cell pooling), and the ability to use one cell preparation for TEM and SEM make this procedure an ideal technique for gold labeling.
Use of colloidal gold in diagnostic surgical pathology
Authors: Warhol Michael J. 
Published: February 2005

AbstractColloidal gold immuno‐electron microscopy is a powerful tool for defining antigenicity at the subcellular level. Such studies permit correlation with cell fractionation studies. They also allow one to assess the specificity of a particular antibody.The most useful reagent for immuno‐electron microscopy is colloidal gold stabilized by a binding protein, either staphyloccocal protein A or immunoglobulin. This method permits highly discrete labeling, and the system is useful for most antibodies used in diagnostic pathology.