bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tissue ferritin concentration in breast carcinoma: A possible marker of proliferative index (A cytosol and Electron Microscopic study)
Authors: Elliott Robert L. , Ledford Lindsay , Werneke Debra , Elliott Mary C. 
Published: June 2020

Elevation of serum ferritin in carcinoma of the breast is well known and levels suggest the severity of the disease. Weinstein et al. found that malignant tissue had six times the ferritin concentration as did benign breast tissue. Malignancies with the highest ferritin concentration were histologically more anaplastic suggesting that the major site of the increased ferritin was the malignant epithelium. They postulated that ferritin may be a marker of neoplasia.To confirm and expand on this study and increase our knowledge on the role of transferrin receptors and iron metabolism in breast cancer, we measured tissue ferritin in cytosol extracts in 44 mammary carcinomas and 11 benign breast tissues. All specimens were examined ultrastructurally. Ferritin concentrations in malignant specimens ranged from 192-12,308 ng/mcp while in benign tissue it ranged from 33-296 ng/mcp. Electron microscopy showed abundant ferritin deposits in malignant epithelium while deposits were sparse in benign epithelium and connective tissue stroma.
Deficiency of leukocyte adhesion molecules
Authors: Hawkins H.K. , Smith C. W. , Anderson D. C. 
Published: June 2020

Study of patients congenitally deficient in expression of the CD11/CD18 dimer has clarified the fundamental role of these transmembrane glycoproteins of the integrin family in multiple functions of polymorphonuclear leukocytes (PMNL). Deficient expression is associated with severe deficiency of PMNL aggregation, adhesion to protein-coated surfaces and endothelial monolayers, locomotion, chemotaxis, phagocytosis and bacterial cell killing. Severely affected patients develop leukocytosis and die in infancy of overwhelming infection. A patient we studied at autopsy died from septicemia and pneumonia. There was striking lack of any acute inflammatory response near sites of necrosis and infection. In the lungs, in contrast, a distinct but deficient acute focal inflammatory response was observed.We used colloidal gold immunolabeling to study the subcellular localization of the CD11/CD18 adhesion molecules in human PMNL and their expression and movement on cell surfaces after stimulation with the chemotactic peptide formyl-met-leu-phe (fMLP). Human PMNL in pyrogen-free PBS were fixed for lh in 1% glutaraldehyde, dehydrated to 70% ethanol and embedded in LR White resin at 55°C. A polyclonal rabbit antiserum recognizing CD18 and absorbed with CD18-deficient PMNL was used to label sites of storage in thin sections, using 5-nm goat-anti-rabbit-IgG gold. We compared sites labeling for CD18, lactoferrin and gelatinase in adjacent thin sections. For surface labeling, cells were fixed in 1% glutaraldehyde for lh, exposed to OKM1 monoclonal antibody, washed and labeled using 36-nm rabbit-anti-mouse-IgG-gold. Controls for both studies included substitution of other or nonspecific primary and secondary antibody. Cells were attached to polylysine-coated coverslips, critical-point dried in CO2, carbon coated and examined by scanning EM using backscattered electron imaging. Other cells were exposed to f(ab’)2 fragments of OKMl and to f (ab’)2-rabbit-anti-mouse prior to fixation, followed by labeling with 36-nm goat-anti-rabbit-gold, or exposed to f(ab’)2-OKMl conjugated to 36-nm gold particles prior to fixation.
Septate-like junction of neoplastic cells in myxopapillary ependymoma of the human filum terminale
Authors: Ho Khang-Loon 
Published: June 2020

Since the first description of septate desmosomes by Wood the term septate junction has been used to describe various junctional structures where in transverse section the intercellular space is partitioned by more or less regularly spaced septa. While septate junction is a common intercellular feature of invertebrate epithelium, vertebrates do not possess septate junctions. There have been occasional reports in the literature of septate-like structures in vertebrate tissues, mainly in nervous tissue and between epithelial cells.In an ultrastructural study of three cases of myxopapi1lary ependymoma of the fi1um terminale, structures similar to septate junction were observed in two cases. They were circumferential bands around the finger-like processes of neoplastic cells wherein slightly widened 30-40 nm intercel1ular spaces (as compared to 15-20 nm in non-junctional region) were transversed at regular intervals by parallel septa resulting in characteristic ladder-like appearance (Fig.1,2). The electron-dense septa, 30-40 nm in cross-length and 20-30 nm in width, were arranged in a periodicity of 40-50 nm. The septa connected to the outer leaflets of the apposing cytoplasmic membranes which appeared undisrupted. Most junctions were short the longest one contained 15 septa in a length of 1.4 um. Similar septa in the same intervals were also noted between the cytoplasmic membrane and the investing basement membrane(Fig.3). Junctional complexes such as zonula adherens and gap junction were often present in the vicinity(Fig.4). Septate-like junctions have not been described in previous studies of myxopapi11ary ependymoma nor in other human brain tumors. Similar junctions have not been observed in the normal conus medullaris nor fi1um terminale. They may represent a specific intercel 1ular feature of myxopapi11ary ependymoma.
Localization of Bacillus thuringiensis Kurstaki toxin binding sites by means of BT toxin gold probes
Authors: Armbruster B. L. , della-Cioppa G. R. 
Published: June 2020

Strains of the bacterium Baci11us thuringiensis (Bt) produce toxins which, when ingested by susceptible larvae, function as a microbial insecticide. In addition to this broad spectrum activity against lepidopteran and dipteran larvae, the toxin has no effect on humans, animals and beneficial insects. As a corollary to our effort to genetically engineer Bt toxin production in major crop plants, we have studied the basic toxin-membrane interactions in the midgut region of Manduca sexta (tobacco hornworm) larvae by means of Bt toxin coated colloidal gold probes.The midgut of 2nd instar M.sexta larvae was removed, incised along its length, inverted and incubated for minimal time in phosphate buffer. Bt gold probes were produced by incubating 15nm diameter colloidal gold in the purified 68kDa active toxin fragment. Dissected midgut was placed in drops of Bt toxin gold solution for 1, 4, 8, 16, and 32min. The samples were fixed for 3hr in 2% glutaraldehyde, post-fixed in 1 % osmium tetroxide, dehydrated in a graded ethanol series and embedded in Embed 812.
Quantitative immunogold localization of laminin and Type IV collagen in gastric mucosa
Authors: Smith Kathryn B. , Schmidt Karmen L. 
Published: June 2020

Upon exposure to alcohol, necrotic lesions form in the gastric mucosa and surface epithelial cells detach leaving an exposed basal lamina. Since the basal lamina acts as a scaffold during restitution and repair in other organs, it may play a significant role in gastric tissue recovery, directing epithelial cell migration to the denuded surface. Type IV collagen and laminin are two of the major macromolecules which compose the basal lamina type IV collagen furnishes strength and flexibility, while laminin functions in cell adhesion and migration. However, despite the likely role of the basal lamina in gastric tissue restitution and repair, it has not been studied as a target of alcohol injury. The technique of TEM immunocytochemistry enabled us to quantify the response of the basal lamina to acute alcohol through examining ensuing changes in immunogold labelling (IG) to type IV collagen and laminin in rat gastric mucosa.Female Sprague-Dawley rats weighing 180-200 g were fasted overnight. The next day 1 ml of 50%, 100% ethanol (50E, 100E) or saline (S) was administered via orogastric tube. After either 5 or 60 min, anesthetized animals were perfused with fixative. For IG studies, gastric tissues were fixed with 1% paraformaldehyde, which is known to preserve the antigenicity of basal lamina components. Since ultrastructural characteristics were not optimal with this fixative, however, parallel TEM studies were also executed using standard techniques. Tissues for IG studies were embedded in Lowicryl K4M at -30°C, sectioned, and incubated in anti-type IV collagen or anti-laminin followed by protein A-gold. Uranyl acetate-stained sections were viewed on a JEOL 1200EX TEM at 60kV. Micrographs from the interfoveolar, pit and gland isthmus regions of the gastric mucosa were examined at 30,000x, the area of lamina densa measured and number of gold particles per area counted. Results were analyzed using analysis of variance and Student-Newman-Keuls’ test for multiple comparisons (α= 0.05).
The binding of potassium to proteins and to nucleic acids best explains the potassium ion content of cells
Authors: Cameron I. , Haskin C. , Hunter K. , Smith N. K. R. 
Published: June 2020

It is generally assumed that the Mg2+ dependent Na+, K+ ATPase “pump” located within the plasma membrane is the primary mechanism responsible for both the generation and the maintenance of the well known intra- to extracellular Na+ -K+ gradients in mammalian cells. This pump operates to pump out cellular Na+ and pump in K + . It is also generally assumed that Na+ and K+ in the cells are free in solution. If these two assumptions are true one would expect that the Na+ content of a post-mitotic tissue cell population should be negatively correlated to and should be a major predictor of K+ content; and that detergent (Brij 58) permeabilization (disruption of the plasma membrane) would allow free passage of Na+ and K+ down their concentration gradients. This would lead to the rapid loss of cellular K+ and to a rapid increase of cellular Na+. Our recent experiments (Cameron et al. 1988) showed that Brij permeabilized cells do not rapidly lose K+ as predicted by the assumption that K+ is free in the cell.If, on the other hand, most of the cellular K+ is bound to proteins (the major source of total cellular sulfur) and to nucleic acids (the major source of total cellular phosphorus) then the S and P content should he positively correlated to and should be the major predictor of K+ content. Analysis of variation in ion and element content of the cytoplasm of many different cardiac myocytes (n = 90) of the ventricle wall by electron probe x-ray microanalysis in thin freeze-dried cryosections allowed a test of this hypothesis (Fig. 1 and Table 1). Multiple regression analysis showed both S and P content to be positively correlated to and the major predictor of cellular K+ content. In normal post-mitotic cardiac myocytes P and S together explained 70-77% of the variation of cellular K+ content. Inclusion of the Na+ content data to the P and S data did not add further to the prediction of K+ content. These results are interpreted to indicate that cells maintain the majority of their K+ bound to protein and to nucleic acid and that “the pump” is not the primary determinant of the maintenance of cellular K+ content.
Novel epoxy/anhydride alternatives for biological electron microscopy: Physical and performance characteristis of embed 812 and LX 112 in combination with NSA/NMA/DMAE
Authors: Mascorro Joe A. , Kirby Gerald S. 
Published: June 2020

Embedding media based upon an epoxy resin of choice and the acid anhydrides dodecenyl succinic anhydride (DDSA), nadic methyl anhydride (NMA), and catalyzed by the tertiary amine 2,4,6-Tri(dimethylaminomethyl) phenol (DMP-30) are widely used in biological electron microscopy. These media possess a viscosity character that can impair tissue infiltration, particularly if original Epon 812 is utilized as the base resin. Other resins that are considerably less viscous than Epon 812 now are available as replacements. Likewise, nonenyl succinic anhydride (NSA) and dimethylaminoethanol (DMAE) are more fluid than their counterparts DDSA and DMP- 30 commonly used in earlier formulations. This work utilizes novel epoxy and anhydride combinations in order to produce embedding media with desirable flow rate and viscosity parameters that, in turn, would allow the medium to optimally infiltrate tissues. Specifically, embeding media based on EmBed 812 or LX 112 with NSA (in place of DDSA) and DMAE (replacing DMP-30), with NMA remaining constant, are formulated and offered as alternatives for routine biological work.Individual epoxy resins (Table I) or complete embedding media (Tables II-III) were tested for flow rate and viscosity. The novel media were further examined for their ability to infilftrate tissues, polymerize, sectioning and staining character, as well as strength and stability to the electron beam and column vacuum. For physical comparisons, a volume (9 ml) of either resin or media was aspirated into a capillary viscocimeter oriented vertically. The material was then allowed to flow out freely under the influence of gravity and the flow time necessary for the volume to exit was recored (Col B,C; Tables). In addition, the volume flow rate (ml flowing/second; Col D, Tables) was measured. Viscosity (n) could then be determined by using the Hagen-Poiseville relation for laminar flow, n = c.p/Q, where c = a geometric constant from an instrument calibration with water, p = mass density, and Q = volume flow rate. Mass weight and density of the materials were determined as well (Col F,G; Tables). Infiltration schedules utilized were short (1/2 hr 1:1, 3 hrs full resin), intermediate (1/2 hr 1:1, 6 hrs full resin) , or long (1/2 hr 1:1, 6 hrs full resin) in total time. Polymerization schedules ranging from 15 hrs (overnight) through 24, 36, or 48 hrs were tested. Sections demonstrating gold interference colors were collected on unsupported 200- 300 mesh grids and stained sequentially with uranyl acetate and lead citrate.
Sampling and analysis of the air-water interface with SEM and EDS of microlayers
Authors: Smith Randall W. , Dash John 
Published: June 2020

The structure of the air-water interface forms a boundary layer that involves biological ,chemical geological and physical processes in its formation. Freshwater and sea surface microlayers form at the air-water interface and include a diverse assemblage of organic matter, detritus, microorganisms, plankton and heavy metals. The sampling of microlayers and the examination of components is presently a significant area of study because of the input of anthropogenic materials and their accumulation at the air-water interface. The neustonic organisms present in this environment may be sensitive to the toxic components of these inputs. Hardy reports that over 20 different methods have been developed for sampling of microlayers, primarily for bulk chemical analysis. We report here the examination of microlayer films for the documentation of structure and composition.Baier and Gucinski reported the use of Langmuir-Blogett films obtained on germanium prisms for infrared spectroscopic analysis (IR-ATR) of components. The sampling of microlayers has been done by collecting fi1ms on glass plates and teflon drums, We found that microlayers could be collected on 11 mm glass cover slips by pulling a Langmuir-Blogett film from a surface microlayer. Comparative collections were made on methylcel1ulose filter pads. The films could be air-dried or preserved in Lugol's Iodine Several slicks or surface films were sampled in September, 1987 in Chesapeake Bay, Maryland and in August, 1988 in Sequim Bay, Washington, For glass coverslips the films were air-dried, mounted on SEM pegs, ringed with colloidal silver, and sputter coated with Au-Pd, The Langmuir-Blogett film technique maintained the structure of the microlayer intact for examination, SEM observation and EDS analysis were then used to determine organisms and relative concentrations of heavy metals, using a Link AN 10000 EDS system with an ISI SS40 SEM unit. Typical heavy microlayer films are shown in Figure 3.
Transperineurial vessels in the peripheral nerves of humans
Authors: Beggs J.L. , Johnson P.C. , Cleary C. , Watkins C.J. 
Published: June 2020

Nerve fibers in peripheral nerve (PNS) are grouped into fascicles. The perineurial (PN) sheath forms the outer cover of the fascicle and separates the epineurium from the endoneurial compartment which contains the conducting units (nerve fibers) of the PNS. The PN sheath not only serves as a physical protective layer for the vulnerable nerve fibers but also plays a role in maintaining a unique endoneurial environment with respect to endoneurial pressure and chemical composition. All blood vessels that serve the capillary plexuses of the endoneurium pass through the PN sheath. In this study on human nerves, we describe some of the anatomical relationships between PN cells and vascular elements as they pass through the PN sheath. A better understanding of the anatomical arrangement of transperineurial vessels might help explain the pathogenesis of some of the ischemic neuropathies.Segments of nerves (lumbosacral plexus, sciatic, posterior tibial, peroneal and sural) from autopsy and sural nerves from biopsy were prepared for electron microscopy. One μm serial cross-sections of nerve fascicles were stained with paragon. Thin sections for EM were taken at desired levels in the thick-section serial sequence. 3-D reconstruction of 1 μm sections was accomplished using a program provided by Dr. Kinnamon of The High Voltage Electron Microscopy Lab in Boulder, Colorado.
High-resolution scanning electron microscopy in biology
Authors: Tanaka Keiichi 
Published: June 2020

With the development of scanning electron microscope (SEM) with ultrahigh resolution, SEM became to play an important role in not only cytology but also molecular biology. However, the preparation methods observing tiny specimens with such high resolution SEM are not yet established.Although SEM specimens are usually coated with metals for getting electrical conductivity, it is desirable to avoid the metal coating for high resolution SEM, because the coating seriously affects resolution at this level, unless special coating techniques are used. For avoiding charging effect without metal coating, we previously reported a method in which polished carbon plates were used as substrate. In the case almost all incident electrons penetrate through the specimens and do not accumulate in them, when the specimens are smaller than 10nm. By this technique some biological macromolecules including ribosomes, ferritin, immunoglobulin G were clearly observed.Unfortunately some other molecules such as apoferritin, thyroglobulin and immunoglobulin M were difficult to be observed only by the method, because they had very low contrast and were easily damaged by electron beam.
Immunocytochemical localization of lung surfactant proteins by cryoultramicrotomy and freeze-substitution embedding
Authors: Voorhout W.F. , Veenendaal T. , Haagsman H.P. , Slot J.W. 
Published: June 2020

Lung surfactant is composed primarily of phospholipids but contains also about 10% proteins. Its main function is to decrease alveolar surface tension at low transpulmonary pressure to prevent alveolar collaps. Surfactant is stored in lamellar bodies in alveo1lar type II cells and is transformed after secretion in tubular myelin, a lattice-like structure.We investigated the biogenesis of surfactant and the pathways that the large hydrophilic surfactant protein A (SP-A) and the small hydrophobic surfactant protein B (SP-B) follow in human lung by using two different immunocytochemical techniques, the cryo-ultramicrotomy method and a new post-embedding method.In the non-embedded, ultrathin cryosections of the lung, prepared and immunolabeled for SP-A and SP-B as described before, it was impossible to achieve a satisfying preservation of lipid-rich structures like lamellar bodies (Fig. 1 and 2). Nevertheless SP-A and SP-B are detected in remnants of lamellar bodies (Fig. 1 and 2) and SP-A is further found to be present throughout the biosynthetic route, in some multivesicular bodies and over the apical plasma membrane of type II cells (Fig. 1).
Nucleolus-like bodies (Nuages) and annulate lamellae in spermatogonia of fish-tilapia, Oreochromis niloticus
Authors: Guha T. , Prentis P.F. 
Published: June 2020

Type A spermatogonia in tilapia (Oreochromis ni1oticus) have been studied by electron microscopy. These are stem cells from which spermatogenesis beings in this species. In this paper we report presence of two cytoplasmic organelles, annulate lamellae and nucleolus-like bodies (nuages), in type A spermatogonia in O. niloticus.Testes were fixed in 2% gluteraldehyde for 4 hrs. at 4°C and then in 1% osmium tetroxide for 1 hr. at 4°C, both in 0.1M cacodylate buffer (pH 7.4). Fixed tissues were processed in the conventional way for electron microscopy. Thin sections of tissues were stained by uranyl acetate and lead citrate. These were examined in a Carl Zeiss electron microscope operated at 40kV.Nucleolus-like bodies (nuages) have been reported in rat spermatocytes, early postimplantation rat embryos, fish and amphibian oocytes and guppy (fish) spermatogonia. Annulate lamellae have been found in fish spermatogonia and oocytes. Type A spermatogonia (Figs. 1,2,3,4) in O. niloticus show presence of nucleolus-like bodies (nuages) and annulate lamellae in the cytoplasm.
Structure and Function of Nonorthodox Chromatins: II. Preliminary Results on the Localization of Helix-Stabilizing Histone-like Proteins of Thermophilic Archaebacteriae
Authors: Bohrmann B. , Arnold-Schulz-Gahmen B. , Villiger W. , Gyalog R. , Kellenberger E. , Searcy D. , Suryanarayana T. 
Published: June 2020

Sulfolobus acidocaldarius and Thermoplasma acidophilum prefer extreme living conditions of low pH (<3) and/or high temperature (>60°C) for optimal growth. To resist thermal denaturation of DNA it appears to be associated with helix stabilizing proteins.The chromosomal position of archaebacterial cells (the nucleoid) can be detected as ribosome-free space in which the DNA is located, as is shown by immunocytochemistry (fig. 1a,b). Similar to most eukaryotes the protein- DNA-ratio of their chromatin is relatively high (approx. 1:1 weight by weight), so that no aggregation occurs during dehydration for electron microscopy (fig. 2). Despite this aggregation-insensitivity, (2 and poster 1) the distribution of immunocytochemical label of the DNA bound proteins of Sulfolobus acidocaldarius (hsp's: A,B,C,C') is not exclusively connected with the bulk DNA of the nucleoid; only one of these proteins (C') seems to be associated with the bulk DNA.
Electronmicroscopic localization of ribonucleic acids in ciliate Bursaria truncatella during cell division
Authors: Popenko Vladimir , Cherny Natalya , Yakovleva Maria 
Published: June 2020

Highly polyploid somatic nucleus (macronucleus) of ciliate Bursaria truncatella under goes severe changes in morphology during cell division. At first, macronucleus (Ma) condences, diminishes in size and turns perpendicular to longitudinal axis of the cell. After short time, Ma turns again, elongates and only afterwards the process of division itself occurs. The biological meaning of these phenomena is not clear.Localization of RNA in the cells was performed on sections of ciliates B. truncatella, embedded in “Lowicryl K4M” at various stages: (1) before cell division (Figs. 2,3); (11) at the stage of macronucleus condensation; (111) during elongation of Ma (Fig.4); (1111) in young cells (0-5min. after division). For cytochemical labelling we used RNaseAcolloidal gold complexes (RNase-Au), which are known to bind to RNA containing cell ularstructures with high specificity. The influence of different parameters on the reliability and reproducibility of labelling was studied. In addition to the factors, discussed elsewhere, we found that the balance of mono- and bivalent cations is of great significance.