bluuebunny/crossref_metadata_2025_split huggingface dataset:
Vaccinia-lassa recombinant produces lassa-like inclusions
Authors: Goldsmith C. S. , Morrison H. G. , Auperin D. D. , Whitfield S. G. , Palmer E. L. 
Published: June 2020

Lassa virus, a member of the Arenaviridae, is the etiologic agent of Lassa fever. The virus is endemic in widespread areas of West Africa, particularly Nigeria, Liberia, and Sierra Leone. Rough estimates indicate that there are upwards of 300,000 human infections annually, resulting in approximately 5000 fatalities. A safe and effective vaccine for Lassa fever is not yet available. Recent studies in our laboratories have focused on the development of recombinant vaccinia viruses that express the nucleoprotein and envelope glycoproteins of Lassa virus as potential vaccine candidates. Tissue culture cells infected with various recombinant viruses were examined by thin-section TEH for any morphological alterations.Tissue culture cells were infected with wild-type Lassa virus or with recombinant vaccinia viruses expressing either the Lassa virus nucleoprotein (NP). the envelope glycoproteins (GPI,GP2), or NP, GPI, and GP2 in combination. Cells were fixed in 2.5% glutaraldehyde in 0.2M cacodylate buffer, postfixed in buffered 1% osmium tetroxide, and en bloc stained with 4% uranyl acetate. The samples were dehydrated and embedded in Polysciences Epon-substitute and Araldite. Sections were stained with uranyl acetate and lead citrate.
Observation of microtubule-like structures and crystalline array in Azotobacter vinelandii
Authors: Dobbins M. S. , Socolofsky M. D. 
Published: June 2020

Many studies have been conducted on microtubules in eukaryotes, including protozoans, but few have dealt with similar structures in bacteria. Microtubule-1ike structures (MT) have been observed in Proteus mirabilis, Azotobacter vinelandii, and some bacterial L-forms . The function of these MT in prokaryotes is as yet undetermined. Microtubules in eukaryotes are involved in cytoskeleton support, cel1 motility, molecule transport, and the separation of chromosomes during mitosis . It has been suggested that A. vinelandii possesses forty chromosomes per cell , so this investigation speculates on the possibility these MT are involved in some form of chromosomal separation. While observing these structures a crystal lattice was noticed which has not been observed in the aforementioned prokaryotes.Cells were fixed for 10-20 min in 2% glutaraldehyde/0.1M sodium cacodylate (pH 7.2), washed with buffer, post-fixed with 1% OsO4, and stained with uranyl acetate. Samples were thin-sectioned, collected on carbon-coated parlodion- reinforced grids, and post-stained with lead citrate. Other preparations involved whole or lysed cells negatively stained with 2% phosphotungstic acid. All specimens exhibiting MT or the crystalline array were photographed in stereo pair.
Immunocytochemical localization of p65 with one-nanometer gold particles following silver development
Authors: Burry Richard W. , Hayes Diane M. 
Published: June 2020

Electron microscopic (EM) immunocytochemistry localization of the neuron specific protein p65 could show which organelles contain this antigen. Antibodies (Ab) labeled with horseradish peroxidase (HRP) followed by chromogen development show a broad diffuse label distribution within cells and restricting identification of organelles. Particulate label (e.g. 10 nm colloidal gold) is highly desirable but not practical because penetration into cells requires destroying the plasma membrane. We report pre-embedding immunocytochemistry with a particulate marker, 1 nm gold, that will pass through membranes treated with saponin, a mild detergent.Cell cultures of the rat cerebellum were fixed in buffered 4% paraformaldehyde and 0.1% glutaraldehyde (Glut.). The buffer for all incubations and rinses was phosphate buffered saline with: 1% calf serum, 0.2% saponin, 0.1% gelatin, 50 mM glycine 1 mg/ml bovine serum albumin, and (not in the HRP labeled cultures) 0.02% sodium azide. The monoclonal #48 to p65 was used with three label systems: HRP, 1 nm avidin gold with IntenSE M development, and 1 nm avidin gold with Danscher development.
Cellular and structural diversity of Campylobacter pylori
Authors: Crooker A. R. , Myers M. C. , Kraft W. G. 
Published: June 2020

Campylobacter pylori is a recently recognized microaerophilic, gram-negative bacterium found in the upper gastrointestinal tract of humans. The role of this organism in the pathogenesis of gastritis and ulceration is currently under intense investigation. The rapidly growing literature on C. pylori describes the bacterium as spiral shaped; however, oval and coccal forms are occasionally noted. We report here on the cellular and structural diversity of this organism, including a new, pleomorphic form.Two Peruvian clinical isolates of C. pylori and the type strain NCTC 11638 were grown for up to 120 h in liquid media. Thin sections and negatively-stained whole mounts were prepared for electron microscopy. Chemical fixation was performed in suspension with 2% cacodylate-buffered glutaraldehyde followed by 2% OsO4 In the same buffer, then uranyl acetate en bloc. Specimens were dehydrated in acetone and embedded in Spurr's resin. Ultrathin silver sections were stained with uranyl acetate and Reynolds’ lead citrate. Briefly prefixed bacteria were negatively-stained with 1% PTA on SiO/Forravar-coated 300 mesh grids.
MDX mouse myopathy I: Presence or absence of sarcolemmal lesions in tibialis anterior muscles from mice of different ages
Authors: Geissinger H.D. , Rhodes L.D. 
Published: June 2020

Since the ‘mdx’ mouse appears to have the same basic defect as sufferers of human Duchenne Muscular Dystrophy (DMD), much recent interest in this possible animal model for the human disease has been generated. Perforations in the sarcolemma have been reported recently in the necrotic tibialis anterior (TA) of 35-days-old and the extensor digitorum longus muscles of 39-days-old ‘mdx’ mice. It is the purpose of this communication to find out if these lesions occur not only in necrotic, but also in unaffected, or in centronucleated fibers of the TA of mice which are younger than 35, or older than 39 days.METHODS: TA from 22-, 25-, 41-, 61- and 99-days-old C57BL/10ScSn/MDX and C57BL/lOScSn control mice were pinned on corkboard in a relaxed state, prefixed for 30 minutes in 2.5% glutaraldehyde followed by routine processing for TEM. Appropriate micrographs were evaluated for a more detailed morphological analysis
of the sarcolemma (SL) and the basal lamina (BL).RESULTS: It should be stated beforehand that in all muscles examined the BL appeared to be intact. In the muscles of a 25-days-old control mouse the SL appeared quite intact (FIG. 1). In contrast to this small perforations or large tears in the SL could be seen in otherwise unaffected muscles of 22- (FIG. 2), 25-
and 41-days-old ‘mdx’ mice, as well as in necrotic and regenerating fibers of mice
from these ages.
SEM and TEM observations of sperm development in the testis of the freshwater fish Oreochromis mossambicus
Authors: Cornish Daryl A. , Smit George L. 
Published: June 2020

Oreochromis mossambicus is currently receiving much attention as a candidater species for aquaculture programs within Southern Africa. This has stimulated interest in its breeding cycle as well as the morphological characteristics of the gonads. Limited information is available on SEM and TEM observations of the male gonads. It is known that the testis of O. mossambicus is a paired, intra-abdominal structure of the lobular type, although further details of its characteristics are not known. Current investigations have shown that spermatids reach full maturity some two months after the female becomes gravid. Throughout the year, the testes contain spermatids at various stages of development although spermiogenesis appears to be maximal during November when spawning occurs. This paper describes the morphological and ultrastructural characteristics of the testes and spermatids.Specimens of this fish were collected at Syferkuil Dam, 8 km north- west of the University of the North over a twelve month period, sacrificed and the testes excised.
The ultrastructure of the developing sperm tail middle piece in the skink Eumeces latices (Lacertilia: Scincidae)
Authors: Okia Nathan O. 
Published: June 2020

The typical reptilian sperm has only a head and tail without the neck. However, the proximal centriole is capped by a neck cylinder, which also encloses the connecting piece and the base of the axoneme. Much variation in the ultrastructure of reptilian sperm tails is found in the connecting piece, neck cylinder and middle piece. yhe current study was aimed at elucidating the ultrastructure of the area between the nucleus and the annulus in the skink Eumeces laticeps, a squamate lizard.Broad-headed skinks Eumeces laticeps were sacrificed between January and May, during the period of spermatogenesis. Testes were fixed in cold Karnofsky’s fixative, pH 7.4, postfixed in 1% OsO4 at room temperature, dehydrated in alcohols and acetone, embedded in Spurr’s epoxy mixture and examined with a Philips 300 EM.In spermatids undergoing chromatin condensation, dense material appears in the post-nuclear cytoplasm (Fig. 1). Some of this, developing close to the spermatid membrane, might be associated with the developing annulus (Fig. 1 AN), but most of the dense material which concentrates arround the proximal centriole (Figs 1,2,3,5), gives rise to the conical capitulum, and the connecting piece.
Structure of DNA and Nucleosome Observed by Ultrahigh-Resolution SEM
Authors: Inaga Sumire , Osatake Hitoshi , lino Akihiro , Tanaka Keiichi 
Published: June 2020

So far, the ultrastructure of DNA strand and nucleosome had been observed mainly by transmission electron microscopy with some techniques (thin-sectioning, spreading method, replica method and so on). Among them, the freeze-etching replica method gave high magnified images of DNA double helix (Ruben et al., 1989). Further, scanning tunneling microscopy also elucidated the images of major and minor grooves in a helical DNA duplex. Though scanning electron microscopy (SEM) was also applied for observing chromatin structures, it had been difficult to observe clearly such small materials. Because, the resolution of SEM was too poor to investigate such fine structures. The obstruction of resolution, however, was overcome by the development of an ultrahigh resolution SEM (UHS-T1, Tanaka et al., 1985). Using the SEM, we could successfully observed naked DNA strands and nucleosomes of chicken erythrocyte nuclei without any metal-coating.Preparations were made by the microspreading procedure basically according to the method of Seki et al.
Immuno-gold post-embedding labeling for electron microscopy: Technical procedures and potential limitations
Authors: Bendayan Moise 
Published: June 2020

The successful post-embedding immunolabeling of tissue sections requires several essential steps.1) The use of an highly specific and well characterized antibody.2) The use of an efficient probe that will bind the antibody molecule.3) The use of tissue sections prepared for microscopy which will combine good preservation of the cellular structures and retention of protein antigenicity.The characterization of the antibodies and their monospecificity are prerequisite conditions that will determine the final quality of the results.Several immunoprobes are available for the labeling of antigenic sites. The use of protein A or protein G, secondary antibody molecules tagged with colloidal gold particles or the biotin-avidin gold system, have been able to generate very good and reliable results of similar value. The question on the size of the gold particles remains a decision that should be taken according to the results expected. Labeling of large cellular structures and their visualization at low magnification require relatively large gold particles (10 to 15 nm).
Use of a Biodegradable Neuroprosthesis Containing Laminin for Avulsive Peripheral Nerve Injury Results in Early Endoneurial and Perineurial Collagen Type III Formation
Authors: Giammara B. , Anderson E. , Yates P. , Zuniga J. , Hanker J. 
Published: June 2020

The direct anastomosis of nerve stumps is most desirable after peripheral nerve transection. There are many avulsive nerve injuries, however, where a nerve segment is destroyed or must be removed -- and the proximal and distal stumps are separated by a gap requiring bridging. Earlier studies showed that a biodegradable polyester mesh (polyglactin 910, Vicryl™) sleeve can act as a conduit and guide regenerating axons into the distal stump across an 11 mm gap created in rat sciatic nerve. This is facilitated by filling the sleeve with Matrigel™, an extracellular basement membrane gel containing 80% laminin, smaller amounts of collagen type IV, heparan sulfate proteoglycan and entaction. The avulsed sciatic was reconnected in animals examined after 30 and 45 days and sensation and leg movement were much improved.The PATS variation of the PAS reaction can be used to demonstrate all glycomacromolecules containing alpha-diglycol groups. Although it also stains basement membrane or type IV collagen brown, it stains type III collagen or reticulin intensely black.
Myelinated Nerve Fixation Techniques: Problems and Comparative Morphology
Authors: Van Over James E. , Fassel Theresa A. , Hauser Christopher C. , Matloub Hani S. 
Published: June 2020

The morphology of peripheral nerve trauma is necessary to understand the resulting alterations in nerve function. Specific traumas, such as Vibration Syndrome, directly effect nerve function. Earily changes in myelinated axons closely resemble artifact damage due to preperations for electron microscopy. If the correlation between structure and function in traumatic conditions is to be studied, it is imperative to establish a fixation technique that yields consistently good results. It is also important to characterize fixation artifacts and correlate these changes to traumatic damages.Several techniques were compared in an attempt to illustrate the quality of morphology obtained from each fixation. Femoral nerve was microsurgically harvested from Sprague Dawley rats. The nerve was then cut into 1 mm segments and fixed by a variety of methods. The basic fixation was for 2.5 hr in 2.5% glutaraldehyde (GA), followed by 3 10-minute washes in 0.1 M cacodylate buffer pH 7.2, and 2.5 hr post-fixation in 1.0% OSO4 with an additional three washes in buffer.
Study of Sporotrichosis by TEM and SEM
Authors: Li Zhen , Wang Jianha , Suen Zhengcheng , Cu Fei , Li Nan 
Published: June 2020

Sporotrichosis is a common infective mycosis that is caused by Sporotrichum schenckii, a dimorphic fungus. The ultrastructures of primary skin in sporotrichosis in human tissue were observed under a transmission electron microscope (TME) and a scanning electron microscope (SEM). The results are reported below.The primary skin lesions were obtained from patients with sporotrichosis by biopsy. TEM and SEM specimens were prepared by routine methods and refrigeration cutting. Under the TEM, the gap between epidermic kerationcytes was wider than normal and the amount of desmasome decreased. Infiltrations of Langerhans’s cells, granulocytes, lymphocytes, macrophage, and plasma cells were observed in the epidermis. Relicts of S. schenckii were found in the gap of stratum granulosum. A number of inflammatory cells infiltrated into the dermis. Spores of S. schenckii were phagocyted by histiocyte in a shallow layer of the dermis.
Atomic structural images of crystalline cholesterol monohydrate in human atheroma
Authors: Lee Ying-Shiung 
Published: June 2020

To gain further insight regarding the micromechanisms of progression and regression of human atherosclerotic plaques the present study was designed for characterization of crystal lattices of cholesterol monohydrate, demonstration of cholesterol crystallization processes, and identification of crystal disorders of cholesterol monohydrate by means of high resolution electron microscopy (HREM).Clusters of cholesterol clefts containing crystalline cholesterol monohydrate were obtained from atherosclerotic human aortas under a dissecting microscope at autopsy. Cholesterol clefts were milled to a powder with a porcelain pestle. The powdered samples without staining dispersed in distilled water were spread on the copper-grid and dried at room temperature. The air-dried specimens were directly examined by a Hitachi H-9000 high resolution electron microscope operated at 300 KV. High resolution lattice images were taken under an optimal defocus condition. Selected area images and electron diffraction patterns were simultaneously taken for the analysis of crystalline characteristics.
The ultrastructure of the molluscum contagiosum lesion
Authors: Burmeister Veronika , Shelley W.B. 
Published: June 2020

Molluscum contagiosum is unique among the viral induced growths of the skin. Unlike other viral tumors, the molluscum contagiosum lesion is a mass made up of myriads of free, discrete virions. It is not a proliferating growth of epidermal keratinocytes such as one observes in the common wart. There is no better way to perceive the nature of this tumor mass than by scanning electron microscopy.Skin lesions of molluscum contagiosum were excised from patients and immediately fixed in 2.5% glutaraldehyde. After fixation the specimens were rinsed in Millonig’s Phosphate buffer. The entire lesion was than cross-sectioned with a razor blade, postfixed in 1% OsO4, rinsed again in buffer, dehydrated in grading ETOH, critical point dried, positioned on an aluminum stub and gold-coated. Examination was made using a JEOL SEM (JSM-35).
Quantification of the nuclei of human bronchial epithelial cells from electron micrographs for radon risk analysis
Authors: Robbins Edith S. , Meyers Owen A. , Harley Naomi H. 
Published: June 2020

Lung cancer in either smokers or in uranium miners exposed to radon occurs preferentially in the epithelium of the bronchi (airway generations 2 to 6). Accurate carcinogenesis risk/dose modeling requires quantitative data on normal bronchial epithelial parameters including: (a) the average number and volume densities (VD) of the nuclei of the possible target cell types and (b) the distances to the free surface of the nuclei of each type. Current dose models use data from an inadequate 1972 light microscopic study. Since smoking and radon effects may be synergistic, these parameters of the bronchi of smokers and non-smokers should be compared.Human bronchial specimens (72) dissected by airway generation were obtained from non-involved areas of lungs/lobes removed for various pathologies (16 smokers, 8 non-smokers). Samples were fixed with 2% glutaraldehyde, 0.1 M cacodylate, 0.1M sucrose for routine TEM (graded ethanols, Epon embedding, lead and uranyl staining) and sections were examined on a JEOL 1200 EX at l,000x at 60 KV.
Ultrastructural characteristics of experimental splenomegaly in portal hypertensive rats: An scanning electron microscopic study of the red pulp
Authors: Misawa T. , Hataba Y. , Baba N. , Kanaya K. , Sakurai K. , Suzuki T. 
Published: June 2020

Because splenomegaly in humans is generally investigated at advanced stage, little is known about the relationship between the change in portal pressure and the pathological characteristics of splenomegaly or the pathological features of splenomegaly in the early stage. To clarify the relationship between the development of splenomegaly and portal hypertension, a morphological study on splenomegaly induced by portal hypertension was performed mainly by scanning electron microscopy (SEM) in liver cirrhotic rats.Male Wistar rats, weighing 200 to 250 g, were used in this study. Liver cirrhosis was produced by intraperitoneal injections of 4% thioacetamide (TAA) in saline according to the previous report. Rats were divided into 5 groups (n=5 for each): groups 1 to 5 corresponding to 20, 40, 60, 80, and 100 injections of TAA, respectively. As a control for each experimental group, rats were injected with saline instead of TAA. The injection needles were placed in the portal vein trunks and abdominal aorta.
Atypical virus particles in glandular tissues from mice injected with a recombinant murine retrovirus encoding an avian V-MYC oncogene
Authors: Beatrice Murray A. , Schmidt Jörg , Becke Helma , Luz Arne 
Published: June 2020

A murine retrovirus construct encoding an avian v-myc oncogene (gift from B. Vennström EMBL, Heidelberg, F.R.G.) was injected into new born female NMRI mice. All mice developed malignant thymic lymphoblastic lymphoma within four months. Four of 9 mice also developed adenocarcinomas of the pancreas. Tissues were fixed in buffered formalin and samples from the pancreas tumours, lymph nodes, normal pancreas, liver and salivary gland were embedded in epon and examined by transmission electron microscopy.Large numbers of atypical virus-like particles were observed in all the samples from the pancreas tumours, normal pancreas and salivary gland, but only rare scattered particles in lymphomas. The pancreas tumours contained massive accumulations of particles in the intercellular spaces. In the normal pancreas, particles were preferentially located in pocketlike areas between the basal laminar and the surface of acinar cells (Fig.1), as well as in the narrow zone between adjoining acinar cells. Particles were occasionally seen budding from the cell surface.
Effect of ketotifen on the ultrastructure of the Erythrocytic stage of Plasmodium Yoelii in mice
Authors: Han-min Cao , xing-qing Pan 
Published: June 2020

Since plasmodia have developed resistance to many of the drugs widely used as anti-malarials throughout the world, there is thus an urgency in the search for new types of anti-malarials (WHO technical report series 711; Liu et al. 1984). The search is going on worldwide. Several reports of the efficiency of ketotifen have been published in China. Base on biochemical analysis, Pan et al. reported that ketotifen showed strong anti-malarial effects on both a chloroquine sensitive strain of P. yoelii and a chloroquine resistant strain of P. berghei. In this paper we study the ultrastructural changes in plasmodia exposed to ketotifen.Experimental mice were inoculated intraperitoneally with 1 × 10 P.yoelii infected red blood cells. After four days, the parasitemia reach approximately 20-30%. 20mg ketotifen base per kg body weight was given to the mice orally. Blood samples were collected at 1,2,3,6,12,24,36,and 48 hours after drug administration.
Gingival epithelial overgrowth in Renal transplant
Authors: Gonzalez-Jaranay Maximino , Fernández-Segura Eduardo , Moreu Gerardo , Campos Antonio 
Published: June 2020

In the past decade cyclosporine (CsA) has reached wide acceptance in therapy for patients undergoing organ transplant. CsA selectively inhibits T cell function while having a minimal effect on humoral immunity. As with drugs which modulate host responses, sequelae such as gingival overgrowth, are common. Different studies have emphasized the cell biology of fibroblast and immune system cells in gingival connective tissue, but few have approached the gingival epithelium with TEM and SEM. This latter procedure not only gives us pictures of the most supercial layer but also produces three-dimensional images of extensive areas of the gingival mocosa.Specimens of overgrown and healthy tissue obtained during gingivectomy were fixed for TEM in 2.5% cacodylate buffered glutaraldehyde. Postfixation with 1% osmium tetroxide and embedding in Spurr's resin followed. Sections were contrasted with lead citrate and uranyl acetate and examined in a Zeiss EM10C. For SEM specimens after identical fixation, were dehydrated, critical-point dried. Gold sputtercoated and observed in a Philips SEM 505.