bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evidence that a secretory component of the sea urchin egg is routed to yolk platelets after fertilization
Authors: Valdizan M. C. , Decker G. L. 
Published: June 2020

During fertilization the sea urchin egg undergoes a global wave of secretion (the cortical reaction) followed by a period of endocytotic activity involved in membrane retrieval. Using a monoclonal antibody (MAb 1223) that recognizes a 130-kDa glycoprotein found in both the egg and embryo of Strongylocentrotus purpuratus, we recently suggested that glycoproteins bearing the 1223 epitope are stored in the cortical vesicles of the egg, secreted during fertilization, and subsequently endocytosed and routed to yolk platelets, a possible site of degradation.In the current study, to determine whether fertilized eggs could internalize an antibody probe directed at the cell surface, we coupled MAb 1223 to colloidal gold and presented it to eggs that had been stripped of fertilization envelopes and hyaline layers. Gold-conjugated mouse IgG (preimmune), bovine serum albumin (BSA), and goat-antimouse IgG served as controls. Colloidal gold (8 and 15 nm) was prepared and conjugated to BSA or antibody as previously described. For localization of the 1223 antigen in unfertilized eggs MAb 1223-gold was diluted 1:20 in buffer and applied to sections of eggs embedded in Lowicryl K4M. To remove the envelopes and hyaline layers, 20-30 seconds after addition of sperm the eggs were suspended in ice-cold artificial sea water containing 25 mM EGTA and passed through a nylon screen (64 μm mesh). Subsequently, 1 ml aliquots of the denuded eggs [10% suspension (vol/vol)] were gravity settled, removed from the Ca2+-chelator and resuspended in complete sea water. After a second wash, 20 μl aliquots of the eggs were transferred to fresh 1.0 ml volumes of sea water equilibrated at 14°C in the presence of the individual gold probes. The final dilution of the gold probes in sea water was 1:100. After gentle mixing of the eggs and gold probes, at time points 5,15,30 and 60 minutes specimens were fixed and embedded in Spurr resin as previously described.
Tritiated thymidine in the chick embryo inner ear
Authors: Fermin Cesar D. 
Published: June 2020

Development of the chick (Gallus domesticus) inner ear has been studied, and the maturation of cells that detect sound has been analyzed at the E.M. level [1,2,3]. Other workers showed correspondence between ultrastructural maturation and behavioral responses [4,5]. In mammals [6] hair cells mature after ceasation of mitosis {Fig.l}, in a pattern so that older cells are in the base of the cochlea while younger cells are in the apex [7]. But, electrophysiology indicates that cells at the base do not function first. Chicks are precocious with well developed sensory organs at birth, and their embryonic development follows, on a very short time span, a sequence that resembles that of the human ear. This study was undertaken to standarize tritiated thymidine (TT) because resolution of TT in avian embryos differs significantly from mammals [6]. Embryos were injected with 100 μl of TT, and sacrificed 1 or 2 hours later in order to label only those cells that were actively dividing cells at the time of the injection. Specimens were fixed and processed for autoradiography [6].Actively dividing cells incorporate TT after short exposure, with minimal background. It seems that vestibular sensory epithelia {Fig.2} have more dividing cells than the auditory sensory epithelia {Fig.3}, even though the vestibule develop before the cochlea. The ratio between the number of labeled cells over the length of the sensory epithelia is lower in the auditory basilar papilla (0.098 cell/(μm) than in the vestibular utricle (0.77 cell/μm) and saccule (1.66 cell/ μm). When dividing cells were analyzed in the basilar papilla alone, and their distribution displayed along the length of the cochlea over time, older cells were opposite to the VIIIth nerve fibers that innervate those hair cells. A lateral and a longitudinal gradient has been established and hair cells closer to the nerve in the mid-basal area mature earlier than hair cells at both ends of the cochlea [2]. This finding, if occuring in mammals, may explain why mid-frequency are the first to appear [5]. The first 1/3 of the chick cochlea contains mainly short hair cells and are innervated primarily by efferent nerve fibers, which arrive in the cochlea almost a week after the afferent do. Moreover, tall hair cells extend 2/3 of the cochlear length from apex to mid-base and show mature innervation patterns before the short hair cells do. In the short embryonic cochlea, frequencies may be produced first in the what will later be the mid-region because, early in development, that area contains more mature receptors [1,2,3].
Electron Microscopic investigation of crooke’s change in the pituitaries of patients with hypercorticism
Authors: Horvath E. , Kovacs K. , Stefaneanu L. , Losinski N. 
Published: June 2020

Human pituitary corticotropins have unique morphologic markers: bundles of type-1 filaments, measuring approximately 70 A in width and representing cytokeratin. The extreme ring-like accumulation of type-1 filaments, known as Crooke's hyalinization, signals functional suppression of the corticotropins and occurs in endogenous and exogenous glucocorticoid excess, caused by ACTH-secreting pituitary adenoma, glucocorticoid secreting adrenocortical tumor, ectopic ACTH-syndrome and administration of pharmacologic doses of glucocorticoids. Cells of autonomous corticotroph adenomas usually do not show Crooke's hyalin change. A minority of these tumors, however, retains sensitivity to the negative feed-back effect of elevated blood glucocorticoid levels and display typical Crooke’s change.In the present study pituitary corticotropins in various phases of Crooke's hyalinization were investigated in patients with glucocorticoid excess of various origin, applying histology, immunocytochemistry, count of argyrophilic nucleolar organizer regions (AgNOR), and transmission electron microscopy.
Correlation of γ-radioactivity and Scanning Electron Microscopy in measurement of retention of 111Indium-labeled canine endothelial cells on synthetic vascular grafts
Authors: Prendiville E.J. , Verdon S. Laliberté , Gould K. E. , Ramberg K. , Connolly R. J. , Callow A. D. 
Published: June 2020

Endothelial cell (EC) seeding is postulated as a mechanism of improving patency in small caliber vascular grafts. However the majority of seeded EC are lost within 24 hours of restoration of blood flow in previous canine studies . We postulate that the cells have insufficient time to fully develop their attachment to the graft surface prior to exposure to hemodynamic stress. We allowed EC to incubate on fibronectin-coated ePTFE grafts for four different time periods after seeding and measured EC retention after perfusion in a canine ex vivo shunt circuit.Autologous canine EC, were enzymatically harvested, grown to confluence, and labeled with 30 μCi 111 Indium-oxine/80 cm 2 flask. Four groups of 5 cm x 4 mm ID ePTFE vascular prostheses were coated with 1.5 μg/cm.2 human fibronectin, and seeded with 1.5 x 105 EC/ cm.2. After seeding grafts in Group 1 were incubated in complete growth medium for 90 minutes, Group 2 were incubated for 24 hours, Group 3 for 72 hours and Group 4 for 6 days. Grafts were then placed in the canine ex vivo circuit, constructed between femoral artery and vein, and subjected to blood flow of 75 ml per minute for 6 hours. Continuous counting of γ-activity was made possible by placing the seeded graft inside the γ-counter detection crystal for the duration of perfusion. EC retention data after 30 minutes, 2 hours and 6 hours of flow are shown in the table.
Same-section correlative light and electron microscopy
Authors: Rieder C.L. , Alexander S.P. , Bowser S.S. 
Published: June 2020

Epoxy embedded biological material, sectioned for conventional, intermediate or high-voltage electron microscopy (EM), can be visualized within the section with good contrast and detail by phase-contrast or dark-field light microscopy (LM). The contrast of such material is not substantially influenced by the type of embedding resin or section support substrate. It is, however, influenced by the type of fixation (glutaraldehyde with and without osmium postfixation), by heavy metal (uranyl and lead) staining, and by the section thickness. The ability to examine the specimen with the LM, within a section cut for EM, allows each section to be rapidly screened for content prior to examination in the EM. We have found this approach to be particularly useful for studies requiring the ultrastructural examination of a selected area or structure which is large enough to be visualized with the LM but which comprises only a small volume of the embedded material (e.g., centrosomes and nuclei within oocytes; specific regions of large protists.)Same section LM-EM can also be extended to sections cut from cells stained prior to embedding for the immunofluorescent localization of antigens using fluorescein, rhodamine or Texas red-conjugated antibodies. Under these conditions the sections show high resolution patterns of antigen-specific fluorescence against a background void of autoflouorescence. The fidelity in the correlation between the distribution of immunofluorescently labeled antigens and the ultrastructure in the same section can be extended to structures as small as a single microtubule or just a few actin filaments . This approach of same section correlative fluorescence microscopy (FLM) and EM can eliminate the need, in many instances, to employ more complex procedures such as immunoferritin or immunogold for labeling antigens for ultrastructural detection.
Correlative microscopy and microprobe analysis in pathology
Authors: Shelburne J.D. , Estrada H. , Hale M. , Ingram P. , Tucker J.A. 
Published: June 2020

In performing transmission electron microscopic (TEM) studies of biopsies, pathologists must be extremely careful to “aim” the TEM at features of the tumor or pathologic process which are important at the light microscopic (LM) level. Fine structural data devoid of such correlations are generally of no clinical value. For example, a TEM study of a tumor must focus primarily on the tumor cells. Care must be taken not to misidentify stromal cells (e.g., capillaries, fibroblasts) as tumor cells, or else serious errors can occur.Likewise, in performing electron microprobe analysis (EPMA) on biopsies, it is extremely important that the pathologist be able to interpret the spectral findings in light of the H&E section appearance. Like it or not, the current “gold standard” in surgical pathology labs around the world is the H&E stained paraffin section. Accordingly, as in TEM studies, electron microprobe results must be obtained in such a manner that one can relate the findings to the appearance of the biopsy as viewed by light microscopy in an H&E section. If one cannot make that correlation, then one has obtained data that generally will be of little interest to most pathologists and clinicians. Accordingly, our group has stressed the importance of correlative microscopy, and has developed several regimens for analyzing histologic sections. Last year in these proceedings we published a schematic overview of that regimen.
Failure of the beige genotype (bg/bg) to alter the morphology of uterine granulated metrial gland cells
Authors: Yamashiro S. , Bast T. , Croy B.A. 
Published: June 2020

Granulated metrial gland (GMG) cells are bone marrow-derived cells that differentiate from small, lymphoid-like precursor cells to become large granulated lymphocyte-like cells during murine pregnancy. The cells are localized in the mesometrial triangle and decidua basalis by day 8 of gestation, migrate through the mature placenta and become degenerate in late gestation. The function and lineage of GMG cells are unknown but some experiments suggest that they may be NK cells. Mice of genotype scid/scid have a severe combined immunodeficiency and lack functional B and T lymphocytes. However, both NK cells and GMG cells have been demonstrated in scid/scid mice. To determine whether these two populations are of the same lineage we developed mice of genotype scid/scid,bg/bg, providing a morphological marker, the Chediak-Higashi giant granule phenotype, to NK cells and have asked whether GMG cells share this lymphomyeloid phenotype.Small pieces of uterine tissues including endo-myometriura from scid/scid and scid/scid.bg/bg at 12th day of gestation were routinely processed for transmission electron microscopy. Ultrastrueturally, large, oval GMG cells were easily recognizable in both scid/scid (Fig. 1) and scid/bg (Fig. 2) uteri due to their cytological features. Nuclei of these cells contained fine chromatin and prominent nucleolus. The cytoplasm was abundant and contained large amounts of free ribosomes and granular endoplasmic reticulum, well developed Golgi complex and prominent membrane-bound granules of variable shapes and sizes (Figs. 1 & 2). The granules were generally oval to spherical and consisted of two zones. The central homogeneous zone, comprising of about 90% of the granule, was less electron opaque than crescent-shaped, outer zone. The crescent-shaped zone contained minute vacuoles and particles (Figs. 1 & 2 insets). The GMG cells exhibited features commonly seen in secretory cells, which were consistent with previous reports. The inclusion characteristic in Chediak-Higashi syndrome was not observed in the GMG cells of the scid/scid.bg/bg (Fig. 2). These observations are suggestive of GMG cells not sharing the NK cell lineage pathway.
Hepatic cytoprotection in treatment of canine heartworm
Authors: Friesen D.L. , Singh A. , Hitt M.E. 
Published: June 2020

Thiacetarsamide is an arsenic-containing drug used in the treatment of heartworm in dogs. The effective antihelmintic dose is toxic to the host animal. Acetylcysteine decreases the hepatotoxicity of some compounds by forming a conjugate with toxic metabolites of the compound. The purpose of this study was to evaluate the effectiveness of a cytoprotectant for hepatocytes in dogs treated with therapeutic levels of thiacetarsamide.Eighteen dogs were divided randomly into two groups. All dogs were given four doses of thiacetarsamide over two days. Nine dogs were given 10% acetylcysteine 15 min prior to each dose of thiacetarsamide. Needle biopsies of the liver were taken from each dog prior to the treatment and again one week post-treatment. The biopsies were fixed in 2% gluraraldehyde in phosphate buffer, pH 7.3, post-fixed in 1% osmium tetroxide, and processed for electron microscopy. Semithin and thin sections of the liver were examined by light and electron microscopy, respectively, for histopathologic and ultrastructural changes. The specimens were coded and the sample treatment was not known to the researchers at the time of observation.
Phagocytosis of pulmonary deposited particles by Type 1 alveolar epithelium
Authors: Sanders C. L. , McDonald K. E. , Adee R. R. , Lauhala K. E. 
Published: June 2020

The role of the alveolar epithelium in removal of deposited particles from the alveolar air space has not been well defined. Type II cells, although in close proximity to particles, do not participate in the phagocytosis of particles. How ever, a variety of alveolarly deposited particulates are phagocytized by type I cells. The rapid and efficient phagocytosis of particles in the air space by macrophages minimizes particle entry into more fixed tissues of the lung.Female, Wistar, young adult rats were given a single intratracheal instillation of either 25 mg iron oxide with a particle size range of 0.3-1.1 micron or 3 mg latex beads with a particle size range of 0.3-0.6 micron, suspended in 1.0 ml 0.9% NaCl solution. Groups of 2-3 rats were killed by halothane overexposure at 5-180 minutes after instillation. The lungs were fixed in situ with McDowellTrumps. Lung tissue was embedded in plastic and stained-with uranyl acetate and lead citrate for electron microscopic examination.
Microscopic study of fetal hypothalamic tissue transplanted into the third ventricle of senescent female rats
Authors: Schneider B.L. , Morley B.J. , Rodriguez-Sierra J.F. 
Published: June 2020

As the female rat ages, her ovarian cycles become irregular and she ceases to ovulate. This aging process of reproductive function appears to be partially due to a neurodegenerative process in the hypothalamic areas responsible for the control of the anterior pituitary gland. There has been some success in recovery of function after transplantation of neural tissue in some cases of genetic neural deficits or in deficits due to lesions of the hypothalamus. This experiment was conducted to determine whether the senescent female rat will regain her ability to ovulate after fetal hypothalamic transplants. Here we describe the morphological development of the hypothalamic transplants.Basal hypothalamic or cortical (control) tissue from fetal rats at 17E were transplanted into senescent Sprague-Dawley female rats demonstrating the cessation of ovulation. Fetal tissue was mechanically dissociated and placed in artificial CSF. Ten μI aliquots of the transplant preparation were infused into the third ventricle of 6 experimental and 6 control animals with a 26 ga Hamilton syringe at a rate of 1 μl/min. The needle remained in place for 5 additional min before it was removed. Animals were monitored for vaginal cyclicity for 30 days. Cyclicity was partially restored in animals transplanted with hypothalamic but not cortical tissue.
Light and electron microscopic demonstration by the PATS reaction of peripheral nerve regeneration
Authors: Giammara B. , Anderson E. , Yates P. , Hanker J. 
Published: June 2020

Although periodic acid-Schiff(PAS) type reactions have been applied to nervous tissues for many years, interest has centered upon staining glycolipids, principally myelin constituents such as the class of sphingolipids. The staining of these compounds such as sphingomyelin has generally been attributed to the presence of amino and hydroxyl groups on adjacent carbon atoms of carbohydrate of the sphingosine moiety. But unsaturated lipids also give the reaction and sphingolipids stain even if carbohydrate moieties are absent. This reaction has been used for staining myelin sheaths but lipid solvents must be avoided in processing the specimens. Toluidine blue staining of semi-thin sections of epoxy- embedded nerve specimens has also been widely used to study regenerating fibers after nerve transection or avulsion. A recent study was made in our laboratories of conduits (sleeves) tailored from biodegradable polyester (VicrylR) mesh to guide the reconnection of regenerating fibers from the proximal stump of a rat sciatic nerve, across an 11 mm gap, with fibers in the distal stump of the interrupted nerve. Complete reconnection of the stumps was observed as early as one month after creating the avulsive nerve injury.Comparison of transverse sections of the repaired sciatic with sections of control nerve with the toluidine blue stain, however, showed little evidence of axonal regeneration after one month (Figs. 1,3). A variation of the PAS reaction (depositing silver) for light and electron microscopy developed in our laboratories (PATS reaction, 5) was than applied to the study of the semi-thin sections of the epoxy-embedded control and repaired sciatic nerves of the same rat one month postsurgery. Correlative light and scanning electron microscopy by SEI and BEI modes could then be performed since the PATS reaction produced very satisfactory staining of the semi-thin sections (Figs. 3-5). Myelin was not stained by the PATS reaction in these specimens since the nerves had been processed with lipid solvents for epoxy embedment. Schwann cells, however, were very prominent in control but not in the repaired nerve. The inner layers of endoneurium and all pericapillaries associated with nerve fibers were intensely stained due to their reticulin content in both control and repaired nerve (Figs. 2,4). This was not unexpected because the PATS reaction employs a silver methenamine reagent. Thus, with the PATS reaction axons could be identified in sections of repaired nerve (Fig. 4) that could not be discerned with toluidine blue staining (Fig. 3). In sections of repaired nerve stained with either toluidine blue or the PATS reaction few axons or axis cylinders were observed but more were seen with the PATS stain (Figs. 3,4). In control nerve sections stained with either procedure many were seen (Figs. 1,2).
Site of hemocyanin synthesis in the terrestrial isopod, Armadillidiom vulgare
Authors: Faso L. , Rappa E. , Vernon G. , Witkus R. 
Published: June 2020

Although hemocyanin, an oxygen binding protein, is found freely dissolved in the hemolymph of isopods its site of synthesis is still unknown.Circulating blood cel Is such as granular hemocytes have been implicated in hemocyanin synthesis in a number of arthropods including Astacus astacus and Homarus vulgaris. Circulating blood cells of Armadillidium vulgare were examined using a transmission electron microscope (TEM) for evidence of hemocyanin synthesis.For each experiment hemolymph was collected from twenty adult A. vulgare and fixed for 1 hour in 200 uL of 3.5% glutaraldehyde in 0.1M sodium cacodylate buffer pH 7.4 with 0.05% calcium chloride added. Hemolymph was then centrifuged at 3000 rpm in an IEC-DPR-6000 centrifuge for 15 minutes at 15 degrees centigrade. The supernatant was removed, and the resulting pellet was washed with three changes of sodium cacodylate buffer. Postfixation of the pellet was done in 1%
osmium tetroxide for 1 hour.
Mitosis and cytokinesis in higher plant cells: Scanning Electron Microscopic observations of deplasticized sections
Authors: Russell S.D. , Strout G. W. , Hurd D. M. 
Published: June 2020

Plant cell division is a fundamental process of plant development that has been studied by a myriad of different techniques providing principally two-dimensional information. By using fixatives that extract major components of the cytoplasmic matrix, the essential elements of mitotic division can be readily visualized in the scanning electron microscope, and stereopairs can be collected to visually reconstruct a three-dimensional image.Cells of the onion (Allium cepa L.) were selected for this study as being essentially representative of higher plant cells. Roots were grown over distilled water for 3-5 days, tips were fixed 48h using freshly mixed 1% chromic acid, 10% acetic acid and 37% formaldehyde solution (10:7:3) fixative, dehydrated, embedded in low viscosity resin, sectioned at 2-4 μm, and mounted on gelatin-coated microscope slides. Material was deembedded with 0.5% KOH in 100% methanol, absolute acetone, and benzene (1:1:1) for 30 min; this was neutralized in 1% acetic acid in 100% methanol, rinsed in ethanol, critical point dried in CO2, and coated using Au-Pd in a triode sputter coater. Specimens were viewed on a JEOL JSM-880 SEM at 15 kV using a LaB6 e- source with a probe current <10-11 amperes and a working distance of -1 mm. Stereopairs were photographed at 6° tilt.