bluuebunny/crossref_metadata_2025_split huggingface dataset:
A review of the study of protein secretion applying the protein A–gold immunocytochemical approach
Authors: Bendayan M. , Nanci A. , Herbener G. H. , Grégoire S. , Duhr M. A. 
Published: February 2005

AbstractExocrine and endocrine types of secretion were investigated in various cells by applying the protein A–gold immunocytochemical approach. Several proteins secreted by rat pancreatic and parotid acinar cells, mouse ameloblasts, rat pancreatic B cells and lymph‐node plasma cells, and frog hepatocytes were studied using specific antibodies. While light microscope immunohistochemistry has allowed for good topographical identification of positive cells in tissues, the protein A–gold approach used at the electron microscope level has demonstrated the presence of specific antigenic sites in particular cellular compartments. All secretory proteins studied were detected in the rough endoplasmic reticulum, the Golgi apparatus, and the secretory granules of the corresponding secreting cells. In addition, some of the proteins were also found in lysosome‐like structures. When good ultrastructural preservation of the cellular organelles was achieved, the labeling was revealed with very high resolution and precise localization. In such cases, we found labeling over transitional elements of the endoplasmic reticulum and in smooth vesicles in the Golgi area. The Golgi apparatus was subdivided into three compartments according to differences in labeling: the cisternae on the cisside, those of the trans‐side and the trans‐most rigid one. Quantitative evaluations of the intensities of labeling have allowed for (1) demonstration of the high specificity of the different labelings; (2) revelation of the existence of a gradient of increasing intensity that follows precisely the progress of the proteins along their secretory pathway; and (3) identification of intracellular sites where increments of protein antigenicity occur. Furthermore, they have revealed the existence of alterations in protein processing that occurred under experimental and pathological conditions. Double‐labeling approaches were performed to demonstrate two different antigenic sites on the same tissue section by applying protein A–gold complexes formed by gold particles of different sizes. Protein A–gold immunocytochemistry has also been combined with cytochemical and radioautographic techniques. This review thus demonstrates that high‐resolution quantitative immunocytochemistry can contribute significantly to the investigation of the intracellular processing of secretory proteins. It also illustrates the potential and versatility of the protein A–gold technique, which in combination with other procedures constitutes a powerful method in cell biology.
Quantification of the initial phases of rapid brain enlargement in the chick embryo
Authors: Pacheco Mary A. , Marks R. William , Schoenwolf Gary C. , Desmond Mary E. 
Published: February 2005

AbstractRapid brain enlargement requires a hydraulic mechanism in the chick embryo. Such a mechanism involves a closed, fluid‐filled system that generates positive pressure. For the chick embryo this study (1) determined when rapid brain enlargement begins, (2) assessed the relative contributions of cavity expansion and tissue growth to overall brain enlargement, and (3) evaluated mathematical models of overall brain enlargement and expansion and growth of the component parts. Three to five embryos were collected at each Hamburger and Hamilton stage (11, 12, 14, 16, and 18) and processed for paraffin serial sectioning. Brain growth was determined over a 24‐hr period (stages 11–18) by calculating volumes from area measurements of sections of brains from individual embryos by using a computerized image‐analysis system. Statistical analysis indicated that a linear model adequately described cavity expansion, and a linear model was rejected for the description of tissue growth and total brain enlargement. At the onset of brain enlargement, the cavity expands faster than the tissue grows; but after 12 hr the reverse is true. Initially (i.e., at stage 11), the cavity accounts for 60% of the total brain volume and tissue for 40%. At stages 12–16, cavity and tissue contribute 50% each. Finally at stage 18, cavity accounts for 55% and tissue for 45%. In order to better distinguish changes in cavity expansion and tissue growth over the 24‐hr period studied, this period was divided into four intervals (I‐IV). The rates of both cavity expansion and tissue growth increase between intervals I and II, decrease between intervals II and III, and increase between intervals III and IV. Overall, the brain enlarges 8.5 times, the cavity expands 9.8 times, and the tissue grows 7.6 times. Change in cavity expansion for fixed time intervals is constant; for tissue growth it increases continually. Our results describe the cavity and tissue kinetics that occur during rapid brain enlargement. Such information is important for understanding normal development of the brain and may provide insight into the mechanisms of genesis of certain congenital malformations such as microcephaly and hydrocephaly.
Upper genital tract abnormalities in the Syrian hamster as a result of in utero exposure to diethylstilbestrol. II. Scanning electron microscope analysis of endometrium cell surfaces
Authors: Gilloteaux Jacques , Steggles Alan W. 
Published: February 2005

AbstractUsing scanning electron microscopy (SEM), we show that an in utero exposure to diethylstilbestrol (DES) will induce endometrial abnormalities postnatally. These changes are magnified when a subsequent postnatal DES treatment is given. More specifically, changes in cell surface morphology are associated with alterations in cell size and shape (from columnar to cuboid/squamous), and in microvilli and mucus secretion. Uteri from hamsters treated postnatally with DES and derived from normal (CD) or DES‐treated mothers (DD) show that accumulated mucoid secretion products are not expelled in the uterine lumen but are “stored” in cystic dilated glandular spaces of the fibrocellular stroma of polyps and papillae filling the uterine lumen. Uteri from female hamsters that have been prenatally treated with DES (DC) show endometrial mucosal crypts containing mucus and other cell debris including migrating granulocytes. In all cases, DES‐treated uteri show mucosal cell surface pleomorphism in the sequence DD > CD > DC Merocrine and/or cystic secretions were observed. Microvilli cover cell surfaces and include some rare and peculiar long microvillous growth. In contrast, DC hypoplastic uteri present no secretory activity. Structures similar to those described for CD uteri can be observed only after 250 days of age in DC uteri. This report confirms and complements previous observations, favoring the choice of the hamster as an animal mode for the study of endometrial carcinogenesis.
Comparison of lectin‐staining pattern in testis and epididymis of gerbil, guinea pig, mouse, and nutria
Authors: Arya Manjula , Vanha‐Perttula Tapani 
Published: February 2005

AbstractThe testis and epididymis of gerbil, guinea pig, nutria, and mouse were studied after staining with seven rhodamine‐conjugated lectins to disclose the distribution of glycoproteins with different sugar residues. In the testis, the lectins showed a variable affinity for Leydig cells, tubular basement membrane, cytoplasm, acrosome, and plasma membrane of maturing spermatids as well as for Sertoli cell extensions. During acrosomal development, the staining pattern showed characteristic changes with different lectins indicating a gradual processing of the glycoprotein components. The staining in the Sertoli cell extensions displayed a cyclic change linked with the release of spermatozoa. A nuclear staining was prominent in zygotene and pachytene spermatocytes in the mouse, weak in the nutria, but absent in gerbil and guinea pig. The principal cells of epididymis showed a lectin‐stained Golgi region as well as a similar staining in the apical surface, microvilli, and tubular contents. This staining was most prominent in the caput/corpus regions with some interspecies differences indicating the epididymal areas active in secretion. Narrow cells active in absorption of testis‐derived material were lectin‐positive in the initial segment of mouse, gerbil, and nutria epididymis. Large light cells with a strong affinity for some lectins were found in the proximal cauda of gerbil and guinea‐pig epididymis. In the nutria, corresponding cells were arranged as islands within the low epithelium. The distal cauda of mouse, gerbil, and nutria was the site for lectin‐stained light cells interspersed among the low principal cells. It is concluded that the high and low light cells may be active in the absorption and phagocytosis of residual bodies/cytoplasmic droplets and surplus epididymal secretory material, respectively. Thus, labeled lectins formed a useful tool in the analysis of glycoprotein distribution, processing, secretion, absorption, and degradation in the male reproductive tissues.
Peri‐ and postnatal development of heterogeneity in the amounts of endoplasmic reticulum in mouse hepatocytes
Authors: Kanai Kazuo , Kanamura Shinsuke , Watanabe Jun 
Published: February 2005

AbstractThe surface density and area per cell of the endoplasmic reticulum (ER) in periportal and perihepatic hepatocytes from male ddY mice, “17‐, 18‐, and 19‐day‐old fetuses,” “newborn and 1‐, 5‐, 10‐, and 20‐day‐old animals,” and “adult animals” were analyzed by quantitative electron microscopy. The surface density of rough ER was not significantly different between periportal and perihepatic cells in all age groups examined, except for 19‐day‐old fetuses in which the value was greater in periportal cells than perihepatic cells. The surface density of smooth ER and total (rough and smooth) ER did not significantly differ between the periportal and perihepatic cells from 17‐day‐old fetuses to 5‐day‐old animals. In 10‐ and 20‐day‐old and adult animals, the values of smooth and total ER were greater in perihepatic cells than in periportal cells. When the data were expressed as area per cell, the patterns of subacinar distributions hardly differed, but age‐related changes differed considerably from the patterns seen in the surface density data. The differences were generally caused by the increase in hepatocyte volume between 20 days of age and adulthood, especially in perihepatic cells, and by the changes in volume during the perinatal period. The results show that differences in the surface density and area per cell of smooth and total ER between periportal and perihepatic hepatocytes evident in adult animals are not present in fetal and newborn animals but arise during postnatal development.
Morphometric analysis of circadian variations in the retinal photoreceptor synaptic terminals of the adult and fetal guinea pig
Authors: McCartney Mitchell D. , Dickson D. Howard 
Published: February 2005

AbstractIn order to test whether the alterations in photoreceptor synaptic terminal size and shape reported in lower vertebrates occur in a mammalian visual system, adult and fetal guinea pig retinas were exposed to an LD 12:12 lighting cycle, as well as to long‐term light (LL) and long‐term dark (DD) regimes. Representative random samples from all retinal quadrants, obtained at various times during these lighting regimes, were processed for electron microscopy. The synaptic terminals of all three photoreceptor cell types in this retina (alpha and paranuclear rods, and cones) were analyzed with computer‐assisted morphometrics for changes in their area, perimeter, synaptic vesicle density, and the degree of plasmalemmal infolding. The data showed all three types of adult receptor terminals to have increased area and vesicle density, as well as decreased membrane infolding, during the light period, while both types of rods showed increased perimeter measurements in the dark. Results from adults maintained under extended lighting conditions (LL and DD) showed no difference when compared with sample times during a typical LD 12:12 lighting regimen where clear statistical differences existed. Data from fetal retinas showed no significant sustainable pattern in any of the measured variables. These quantitative findings have led to the conclusion that while alterations in perimeter measurements may be explained by using the vesicle recycling hypothesis, observed changes in terminal size and shape may be controlled by a light‐initiated or light‐enhanced mechanism and effected through an annular configuration of cross‐striated fibrils found within these photoreceptor synaptic terminals.
The effects of orchidectomy and replacement therapy on the ultrastructure and gonadotropin‐releasing hormone content of the median eminence of the rat
Authors: Beckman W. C. 
Published: February 2005

AbstractThe effects of 2 weeks of orchidectomy and replacement therapy with testosterone upon the content and distribution of gonadotropin‐releasing hormone (GnRH) in the median eminence were determined by means of radioimmunoassay and electron microscopy. Photographic montages were prepared from electron micrographs of the lateral median eminence at the point of deepest invagination of the tuberoinfundibular sulcus. Morphometric analysis of photographs of tissues immunohistochemically stained for GnRH was performed to determine changes in the volume density of GnRH‐containing axon profiles following the experimental treatments. A decrease in GnRH content after orchidectomy was observed both by morphometric analysis of axon volume density and radioimmunoassay of total GnRH content. Testosterone treatment of orchidectomized animals prevented the postorchidectomy loss of GnRH. Morphometric analysis of conventional electron micrographs revealed an increase in the number of axons containing no dense‐core vesicles following orchidectomy, but no decrease in volume density of the neuropil. The results indicate that the change in volume density of immunostained axons was related to the loss of immunostainable dense‐core vesicles and not to a change in the size or number of axons. The area corresponding to the location of the highest concentration of GnRH‐containing axons was observed to be largely avascular and separated from the vessels of the tuberoinfundibular sulcus by a “border zone” composed of glial foot processes. The unique morphology of the GnRH area has suggested the name “compact zone” to distinguish it from the palisade zone with which it is continuous medially. GnRH axons in this region are probably part of a tract extending farther caudally rather than a terminal field.
In situ localization of lectin‐binding glycoconjugates in the matrix of growth‐plate cartilage
Authors: Farnum Cornelia E. , Wilsman Norman J. 
Published: February 2005

AbstractIn the distal hypertrophic zone of growth‐plate cartilage, the pericellular matrix surrounding individual chondrocytes and the territorial matrix uniting chondrocytes into columnar groups are invaded by metaphyseal endothelial cells prior to osteogenesis. In the present study, lectin‐binding glycoconjugates were analyzed in these two matrix compartments of growth‐plate cartilage from Yucatan swine. Nine lectin‐fluorescein conjugates were tested by a postembedment method on 1‐μm‐thick, nondecalcified, Epon‐embedded sections. Chondrocytes in all cellular zones were surrounded by a pericellular matrix which showed positive binding for peanut agglutinin (PNA), ricin agglutinin (RCA‐I), and soybean agglutinin (SBA). Binding by these lectins was sensitive to digestion with hyaluronidase, chondroitinase, and trypsin. Pericellular glyconconjugtes that bind RCA‐I and concanvalin A (CONA) after periodic acid oxidation, and which were sensitive to trypsin but not to chondroitinase or hyaluronidase, were present in the hypertrophic cell zone. Within the territorial matrix, binding of lectins specific for galactose, N‐acetylgalactosamine, and fucose showed gradients of intensity which became maximal at the last transverse septum. Lectin‐binding histochemistry more precisely differentiated the microheterogeneity of glycoconjugate distribution within these two matrix compartments than has been possible with other histochemical techniques. Lectin‐binding affinity is a potentially useful technique by which to isolate cartilage matrix macromolecules unique to specific cellular zones of the growth plate.
Factors that determine the form of neuromuscular junctions of intrafusal fibers in the cat
Authors: Kucera Jan , Walro Jon M. 
Published: February 2005

AbstractThe form of terminations of fusimotor (γ) and skeletofusimotor (β) axons on intrafusal fibers was analyzed in serial sections of 20 spindles of the cat tenuissimus muscle. Seven synaptic features were assessed either qualitatively or quantitatively from electron micrographs of transverse sections of 184 intrafusal and 30 extrafusal endings. Features were compared among endings that were terminations of γ or β axons on different types of intrafusal fiber at different distances from the spindle equator. These comparisons indicated that interactions of several factors, and not the motor axon alone, determine the form of motor endings. Intrafusal muscle fiber type is dominant to the motor axon in regulation of the number and depth of postsynaptic folds. Separation of the influence of the motor axon from the muscle fiber was less clear with respect to the size of ending. Complete expression of the muscle fiber–motor axon interaction reflected by the form of motor endings is dependent upon location of the ending relative to the sensory region. Both depth of the primary synaptic cleft and size of the soleplate of motor endings increased with increasing distance of the ending from the spindle equator. A system of classification of cat intrafusal motor endings that reflects the multiplicity of factors that determine the form of endings, and one that simplifies the current terminology, is proposed.
The microfibrils of connective tissue: II. Immunohistochemical detection of the amyloid P component
Authors: Inoué S. , Leblond C. P. , Grant Derrick S. , Rico Philippe 
Published: February 2005

AbstractImmunohistochemical methods were used for the detection of the amyloid P component in the microfibrils of two regions: the zonule of the eye and the connective tissue of the foot pad in 20‐ to 50‐gm mice. Following fixation by immersion in 4% formaldehyde, the eyes and foot pads were embedded in paraffin, and sections were immunostained for light microscopy by using antiamyloid P component antiserum followed by peroxidase‐antiperoxidase procedure. For electron microscopy, formaldehyde‐fixed tissues were immunostained for the amyloid P component with protein A‐gold by using either thin Lowicryl sections or frozen sections which were then embedded in Epon for thin sectioning.In the zonule of the eye, the light microscope showed that zonular fibers were strongly immunostained for the amyloid P component; there was also weak staining of the nonpigmented ciliary epithelium at the distal end of the fibers and of the zonular lamella at their proximal end. The electron microscope revealed clear‐cut immunolabeling of the microfibrils making up zonular fibers as well as of individual microfibrils. In the foot pad, the light microscope detected a weak diffuse staining of connective tissue, whereas the electron microscope showed immunolabeling restricted to microfibrils. It was concluded that the amyloid P component was present in, or associated with, microfibrils.Purified amyloid P component was prepared and examined in the electron microscope after either negative staining or routine processing. After negative staining, it appeared as flat pentagonal units, frequently associated into columns. After routine processing, the units looked like cross sections of microfibrillar tubules. The dimensions of the units matched those of the hypothetical segments of the tubules. It was concluded that this tubule consisted of a column of amyloid P units. The cohesion of the units within the column was likely to be reinforced by the bands present at the surface of microfibrils.
Transitional epithelial zone of the bovine nasal mucosa
Authors: Adams Donald R. 
Published: February 2005

AbstractTo determine the extent and ultrastructure of epithelium lining the transitional nasal mucosa of the neonate, gnotobiotic calf tissues were prepared for scanning and transmission electron microscopy. Stratified cuboid epithelium of the rostral 40% of the nasal cavity contained few ciliated cells; the next caudal 10–15%, although ciliated, had extensive nonciliated areas. The predominant type of surface cell was nonciliated, had short microvilli, and contained a multilobate nucleus and numerous pinocytotic vesicles. In some areas the surface of these cells presented a cobblestone appearance. Basal cells contained numerous bundles of filaments, ribosomes, and basal vesicles. Caudally, nonciliated columnar cells included a cell type similar to the more rostral cuboid cell, as well as brush cells and immature secretory and ciliated cells. Goblet cells were infrequently observed. Intraepithelial nerve terminals were abundant. Other intraepithelial cells, often difficult to identify owing to varying characteristics, included lymphocytes. Based upon comparisons of this neonatal epithelium with mature epithelium, observed in earlier studies of other mammalian species, the transitional mucosa is believed normally to occupy an extensive area of the nasal cavity.
EMG of scapulohumeral muscles in the chimpanzee during reaching and “arboreal” locomotion
Authors: Larson Susan G. , Stern Jack T. 
Published: February 2005

AbstractCurrent views on the function of the deltoid and rotator cuff muscles emphasize their roles in arm‐raising as participants in a scapulohumeral force “couple.” The acceptance of such a mechanism is based primarily on a 1944 EMG study of human shoulder muscle action. More recently, it has been suggested that shoulder joint stabilization constitutes a second and equally important function of the cuff musculature, especially in nonhuman primates which habitually use their forelimbs in overhead postural and locomotor activities. Few comparative data exist, however, on the actual recruitment patterns of these muscles in different species. In order to assess the general applicability of a scapulohumeral force couple model, and the functional significance of the differential development of the scapulohumeral musculature among primate species, we have undertaken a detailed study of shoulder muscle activity patterns in nonhuman primates employing telemetered electromyography, which permits examination of unfettered natural behaviors and locomotion. The results of our research on the chimpanzee, Pan troglodytes, on voluntary reaching and two forms of “arboreal” locomotion reveal four ways in which previous perceptions of the function of the scapulohumeral muscles must be revised: (1) the posterior deltoid is completely different in function from the middle and anterior regions of this muscle; (2) the integrity of the glenohumeral joint during suspensory postures is not maintained solely by osseoligamentous structures; (3) the function of teres minor is entirely different from that of the other rotator cuff muscles and is more similar to the posterior deltoid and teres major; and (4) each remaining member of the rotator cuff plays a distinct, and often unique, role during natural behaviors. These results clearly refute the view that the muscles of the rotator cuff act as a single functional unit in any way, and an alternative to the force couple model is proposed.