bluuebunny/crossref_metadata_2025 huggingface dataset:
Localization of Nicotinic Acetylcholine Receptors on Somatic Spines of Chick Ciliary Ganglion Neurons
Authors: Shoop R , Martone M , Yamada N , Ellisman M , Berg D
Published: July 2020

Nicotinic acetylcholine receptors (nAChRs) are pentameric membrane proteins that function as cation selective, ligand-gated ion channels and are widely distributed throughout the vertebrate nervous system. One of the most abundant nAChRs is a species that contains the α7 gene product (α7-AChRs), binds the snake venom oc-bungarotoxin, and rapidly desensitizes. These receptors have been shown to function at presynaptic sites to modulate transmitter release, as well as on postsynaptic cells where they mediate transmission. Interestingly, these receptors have an exceptionally high relative permeability to calcium.

In the chick ciliary ganglion, the α 7-AChRs play a prominent role, by generating large synaptic currents, but the receptors appear to be excluded from postysnaptic densities on the cell. Immunohistochemical studies have shown that the receptors form large clusters on the surface of the ciliary ganglion neurons. We have recently shown that the α 7-containing receptors are concentrated on mats of somatic spines in close proximity to putative sites of presynaptic transmitter release.
Molecular Mechanisms of Self-Assembly and Polymorphic Switching of the Bacterial Flagellum
Authors: Hasegawa Kazuya , Yamashita Ichiro , Mimori-Kiyosue Yuko , Vonderviszt Ferenc , Namba Keiichi
Published: July 2020

Bacterial flagellum is a helical filament by means of which bacteria swim. Each filament rotated by the motor at its base works as a screw that propels the cell, but it is not simply a rigid propeller. The filament is normally in a left-handed supercoiled form and several of them form a bundle when bacteria swim. Upon quick reversal of the motor rotation, which occurs every few seconds, the filament switches into a right-handed supercoil, making the filament bundle fall apart and enabling the cell to tumble for its tactic behavior. The filament is a tubular structure formed by helical assembly of single protein, flagellin, whose molecular mass is 51.5 kDa in the case of Salmonella typhimurium, which we study. The supercoiling of the filament is thought to involve two distinct subunit conformations and/or packing, whose mechanism is interesting in terms of conformational distinctness and adaptability of flagellin.

To understand the mechanisms of self-assembly and polymorphism of the filament, electron cryomicroscopy (EM) and X-ray fiber diffraction have been used to analyze the structures of two straight filaments with distinct helical symmetries.
Requirement of Prolonged Calcium Increases For the Induction of Nuclear Camca4 Signals
Authors: Teruel Mary N , Meyer Tobias
Published: July 2020

Calmodulin is thought to be the most important calcium sensor in signal transduction. When calcium binds to its 4 calcium binding sites, CaMCa4 becomes a multifunctional activator that regulates a large number of critical cell functions. In the nucleus, CaMCa4 controls gene transcription and other important nuclear processes. Here, using confocal microscopy to measure changes in fluorescence resonance energy transfer (FRET) of an indicator composed of two GFP-variants (CFP and YFP) linked by a calmodulin-binding sequence, we show that free cytosolic CaMCa4 concentration increased rapidly after a cell-wide increase in calcium concentration while the initial free CaMCa4 in the nucleus remained much lower and only equilibrated to the cytosolic CaMCa4 concentration after a delay of 1-2 minutes. Thus, immediately after a cell-wide calcium increase, a significant gradient in free CaMCa4 concentration exists between the cytosol and nucleus.
Increase In Intracellular Sodium Evoked by Glutamate Transporter Activation In Cortical Astrocytes: A Fluorescence Microscopy Analysis
Authors: Chatton J-Y , Marquet P , Magistretti PJ
Published: July 2020

Primary cultures of mouse cortical astrocytes were used to investigate the changes in intracellular Na+ concentration ([Na+]i) following exposure to the excitatory neurotransmitter glutamate. The fluorescent probe sodium-binding benzofuran isophthalate (SBFI) was used to measure [Na+]i by epifluorescence microscopy imaging. Detection of the low light level fluorescent signal was accomplished using a Gen III+ intensified CCD camera. Fluorescence excitation ratio images of dye-loaded cells were obtained after sequential illumination at 340nnm and 380nm, with an emission observed at >520nm. Ratio images were proportional in intensity to [Na+]i. In situ calibration of the fluorescent signals was obtained for each experiment and each cell under study by equilibrating [Na+]i with external Na+ after treatment with the cation ionophores monensin and gramicidin, and with ouabain, a specific inhibitor of the Na+/K+ ATPase. Cells on glass coverslips were perfused at 35°C in a closed microscope chamber using solutions buffered with 25 mM bicarbonate/5%CO2.
Quantitative Imaging of Metabolism by Two-Photon Excitation Microscopy
Authors: Piston David W , Knobel Susan , Patterson George
Published: July 2020

Two-photon excitation microscopy provides attractive advantages over confocal microscopy for three-dimensionally resolved fluorescence imaging. Because of the intensity-squared dependence of the two-photon absorption, the excitation is limited to the focal volume. This inherent localization minimizes photobleaching and photodamage - the ultimate limiting factors in fluorescence microscopy of living cells. One of the most powerful applications of two-photon excitation microscopy is imaging from the naturally occurring reduced pyridine nucleotides (NAD(P)H). NAD(P)H is a useful indicator of cellular metabolism, but it is not a “good“ fluorophore (it has a small absorption cross-section and a low quantum yield). Two-photon excitation of NAD(P)H yields minimal photodamage, thus allowing time-resolved threedimensional metabolic mapping of cellular redox state. We have used two-photon excitation microscopy to examine glucose metabolism in pancreatic and muscle cells. As glucose is metabolized by these cells, intermediate metabolism results in an increase in the reduced-tooxidized NAD(P)H/NAD(P)+ ratio, and a concomitant increase in autofluorescence.
Phytofluors: Phytochrome-Based Orange Fluorescent Protein Probes
Authors: Clark Lagarias J , Montgomery Beronda L , Murphy John T , Wu Shu-Hsing
Published: July 2020

Plants sense the light environment using pigment-protein complexes that discriminate light color, intensity, duration and direction. The most well-studied of these photoreceptors are the phytochromes, a family of soluble biliproteins found in plants, algae and cyanobacteria. Owing to the linear tetrapyrrole pigment phytochromobilin (PΦB) or phycocyanobilin (PCB) that is covalently linked to a large polypeptide via a thioether linkage, phytochromes perceive differences in the quality and quantity of light via their ability to photointerconvert between red (λmax660 nm) and far-red (λmax730 nm) light absorbing forms. Due to an efficient Z,E photoisomerization of the double bond between the C and D-ring pyrroles, phytochromes are nonfluorescent proteins with fluorescent quantum yields less than 10“3 at room temperature (Figure 1).

Phytochrome genes have been cloned from a wide variety of photosynthetic organisms.
Submembrane Events In Triggerable Cells Studied by Total Internal Reflection Fluorescence Microscopy.
Authors: Axelrod D , Johns LM , Levitan ES , Omann GM , Holz RW
Published: July 2020

We have studied the dynamics of certain key processes near the plasma membrane inside two types of chemically-triggerable living cells using total internal reflection fluorescence microscopy (TIRFM). In TIRFM, a laser beam is incident upon the cell/glass-substrate interface from the glass side at an angle greater than the critical angle for total internal reflection. This creates an exponentially decaying evanescent field in the cell medium (with a characteristic depth of > 100 nm) capable of exciting fluorescence selectively from the membrane-proximal regions at cell/substrate contacts. Various ways of setting up the optics for such a system are discussed, involving the use of either prisms or very high aperture objectives.

In one application of TIRFM, the motion of adrenalin-containing secretory granules in the immediate submembrane region of chromaffin cells is examined before and after chemical stimulation that causes the granules to release their contents to the cell exterior.
Imaging Subcellular Changes in Living Mammalian Embryos Using 1047 Nm Two Photon Excitation Fluorescence Microscopy
Authors: Squirrell J M , Wokosin D L , Bavister B D , White J G
Published: July 2020

A major challenge for fluorescence imaging of living cells is maintaining viability during and following prolonged exposure to excitation illumination, especially when imaging over hours or even days, as when studying mammalian embryonic development. The use of specific fluorescently labeled components in living embryos promises to reveal the roles of organelles and molecules in a native and reproducible context. However, to gain a thorough understanding of dynamic biological systems, events of interest must be recorded as they occur, while limiting perturbations caused by the observation technique. Therefore, establishing long-term fluorescence imaging methods that maintain viability is critical for advancing our understanding of cell and developmental biology.

One promising technique for imaging living cells is two photon laser scanning microscopy (TPLSM). The lower energy per photon and the restriction of fluorophore excitation to the imaged focal plane should reduce the total photodamage to thick specimens when compared to conventional laser scanning confocal microscopy (LSCM).
Two-Photon Microscopy as a Useful Tool for Elucidating the Mode of Action of Novel Potential Cancer Therapeutics.
Authors: Navara C S , Uckun F M
Published: July 2020

Multiphoton microscopy allows us to follow specific cellular structures (ie. nuclei, mitochondria, and the plasma membrane) in a high resolution three dimensional and time resolved fashion. We have used multiphoton confocal microscopy to evaluate the cellular effects of potential cancer therapeutics. Cancer cells were plated onto coverslips and labelled with either the vital DNA dye Hoechst to image the nuclei and chromosomes or the lipid dye DiA to label the plasma membrane. Both of these dyes can be imaged with several sections without affecting cell viability as assessed by cell motility and the ability to undergo mitosis and cytokinesis.

We have used this technology to show that one compound (DDE 131) rapidly induces in cancer cell lines the hallmarks of apoptosis; DNA hypercondensation, nuclear fragmentation and rapid membrane blebbing. In a leukemic cell line these changes take place within 20 minutes of treatment.
Imaging Techniques Combined With Enzyme-Based Procedures That Facilitate the Simultaneous Imaging of Nerves, Neurons, Cartilage And Bones During Development In Gambusia
Authors: Rosa-Molinar E
Published: July 2020

A persistent problem in elucidating the anatomy of the peripheral nervous system has been an inability to stain both myelinated and unmyelinated nerve fibers. To overcome this problem, our laboratory developed two workmg protocols for reliably and differentially labeling and staining the peripheral nervous system and combined them with an enzyme clearing and staining procedure for the simultaneous visualization of bone and cartilage.

One protocol uses anti-acetylated α-tubulin immunohistochemistry to follow the course, peripheral branching, and origin of the ventral spinal nerve innervating the axial musculature and a second uses anterograde and retrograde transport of selectively applied 3000 molecular weight (MW) biotin dextran amines and/or biocytin to identify specific afferent and efferent projections and their cell bodies. Both procedures can be combined with an enzyme clearing and staining procedure for the simultaneous visualization of bone (alizarin red S) and cartilage (alcian blue) in whole-mount preparations.
Approaches for Understanding Dynamic Cell Movements, Cell-Cell Interactions and Tissue Shaping During Embryogenesis of the Vertebrate Body Plan
Authors: Schoenwolf GC
Published: July 2020

The early vertebrate embryo develops a characteristic tube-within-a-tube body plan. This plan is realized through a series of cell movements and cell-cell interactions that collectively result in tissue shaping and the formation of the three-dimensional body plan. Tissue shaping is a highly choreographed process that is under the control of the organizer--a specialized region of the embryo that is both sufficient and required for formation of the body plan. Recent technical advances have greatly increased our understanding of the role of the organizer in vertebrate embryogenesis. Such advances include the use of new cellular, molecular, genetic, and embryological approaches.

A hallmark of embryogenesis is its dynamic nature. Classically, embryos were studied in three major ways. 1) With morphological/descriptive analysis, initially involving histological procedures (stained whole mounts and serial sections cut in the three cardinal axes) and more recently electron microscopy.
Microscopic Characterization of Ocular Development and Disease
Authors: Potts J , Conley P , Champion R
Published: July 2020

The embryonic lens contains two populations of cells, lens epithelial cells and lens fiber cells. As the growth of the human lens is linear from the age of 10 to 90, lens epithelial cells divide and differentiate into fiber cells at a uniform rate during adulthood. Any defects that arise during fiber formation will remain in the lens. We postulate that regulation of early lens growth is critical for the onset of cataracts that usually occur later in life. Slowing the growth of the lens could therefore provide a strategy to suppress the formation of cataracts. However, the factor(s) that control lens growth in vivo have not been identified.

We have identified 18 receptor and cytoplasmic kinases present in lens epithelial cells. Using these as potential targets for factors controlling growth, we tested corresponding ligands in a lens epithelial cell proliferation assay. Platelet-derived growth factor (PDGF) proved to promote a growth activity similar to, but distinct from, that of embryo serum.
Microscopy as a Tool in Understanding the Role of Growth Factors in Cardiac Development
Authors: Price Robert L , Thielen Thomas E , Borg Thomas K , Terracio Louis
Published: July 2020

Over the past several years the central roles of several different growth factors in the normal development of the embryonic heart have been identified through a variety of techniques involving microscopy. Initially, most studies consisted of descriptions of gross changes in cardiac morphology associated with naturally occurring mutations that affected growth factor function. More recently the development of specific probes for growth factor receptors that can be used in confocal microscopy have aided in the identification of changes in the temporal and spatial distributions of receptors at various stages of development. The correlation of these changes with developmental events such as valve formation and trabeculation in the heart, in conjunction with biochemical studies and blocking agents for the growth factors have significantly increased our understanding of growth factor function in cardiac development.
Confocal Laser Scanning Microscopy of Whole Mouse and Human Embryos: Apoptosis and Morphology.
Authors: Robert M. Zucker , Kathy Sulik , Price Owen T
Published: July 2020

Two novel sample preparation procedures have been developed to visualize morphological structures in embryonic and fetal tissues. In the first, optimization of the sample preparation allows for the visualization of embryos with a thickness in excess of 500 microns. The morphology of the internal structures in these embryos is observed by optical sectioning. The general sample preparation procedures included paraformaldehyde fixation, methanol dehydration and clearing with either benzyl alcohol/benzyl benzoate or methyl salicylate. The dyes (i.e. LysoTracker Red, YoPro) are incorporated into living or fixed embryos to indicate a specific biological function or embryo morphology. Using these stained embryos, the detection of apoptosis and its subsequent quantification were made in addition to the observation of morphology.

In the second technique, the confocal microscope has been adapted to produce images similar to those generated by a scanning electron microscope. For this application, the embryos are coated with a dilute solution of acridine orange resulting in opaque surface fluorescence.
Aids Dementia Complex
Authors: DeArmond SJ
Published: July 2020

The World Health Organization estimates by the year 2000 that the cumulative total of HIV-1 infected adults and children will be about 30 million worldwide. Disease of the central nervous system (CNS) in association with AIDS is common. 20-30% of AIDS patients will develop varying degrees of cognitive and motor deficits designated the “AIDS dementia Complex (ADC)” or “HIV-1-associated cognitive/motor deficit”. Progression of symptoms is usually slow and irregular. In the end-stage, the patient is severely impaired with mutism, incontinence and prominent motor impairment. Neuroradiologic studies show generalized cortical atrophy and diffuse white matter changes. HIV can be cultured from the CSF. Neurologic involvement in pediatric AIDS is very common with CNS complications usually occurring within the first two postnatal years. Given the severeness of the dementia and motor dysfunction in ADC, one is struck by the paucity of neuropathological features. Hematoxylin and eosin stained sections reveal only three neuropathological features. First, there are small numbers of microglial nodules scattered in the white matter and sometimes in grey matter (Fig. 1). However, microglial nodules occur in virtually all viral infections of the CNS, including CMV micronodular encephalitis in AIDS patients.
Aids: Tubuloreticular Structures (Trs), Cylindrical Confronting Cisternae (Ccc), and Related Alterations
Authors: Sidhu Gurdip S , Cassai Nicholas D
Published: July 2020

TRS and CCC are endoplasmic reticulum membrane-derived structures seen in HIV-infected individuals in a variety of cell types. TRS (synonym: tubuloreticular inclusions) are 24-25 nm in diameter, branching tubules which are short or long and associated with the granular or smooth endoplasmic reticulum, the Golgi complex, the perinuclear cistern, and annulate lamellae (Fig. 1-3, 8). The tubules are noticeably more stretched out in Kaposi's sarcoma endothelial cells, presumably by an increase of matrix material within the reticulum sac (Fig. 3). TRS consist of membranous components, including polypeptides, but lack nucleic acid.

CCC (test tube and ring-shaped forms; curvilinear membranes) are formed by a concentric stacking of two or three cisterns of endoplasmic reticulum resembling nuclear membrane in mitosis (Fig. 7), but with the interposition between the opposing membranes of a layer of electron-dense material that is resistant to lipid solvents (Fig. 4,5,8).
Early Apoptotic Changes in the Leukocytes of Rhesus Macaques Challenged With Chimeric Simian/Human Immunodeficiency Virus (Shiv)
Authors: Bryant NJ , Asher LV , Lewis M , Mascola J , Carpenter C , Hanson C
Published: July 2020

Introduction

Chimeric Simian/Human Immunodeficiency Viruses (SHIV) causes persistent infection characterized by CD4+ T cell lymphopenia in rhesus monkeys. The SHIV model infection closely resembles HIV-1 infection and disease in humans, except that it progresses at an accelerated rate. During the early stages of HIV-1 infection, viral replication is at its highest rate and there is a rapid decline of the immune system. Cell death induced by apoptosis, a feature in the pathogenesis of acquired immunodeficiency syndrome (AIDS) and AIDS-like syndromes of many lentiviral infections, is thought to be important in the progressive decline of lymphocytes and the cell mediated immunity of infected individuals. The apoptosis is not specific for lymphocytes, this phenomenon also occurs in numerous cell types of the immune system, including the polymorphonuclear leukocytes. Abnormalities of neutrophil function and number because of HIV-1 and other retroviral infections have been recognized.
Ultrastructural Examination of an Opportunistic Organism in Acquired Immunodeficiency Syndrome
Authors: Snell K S , Boudreaux C W , King J A C
Published: July 2020

Since the emergence of HIV and its counterpart,acquired immunodeficiency syndrome (AIDS), rare opportunistic organisms have become increasingly prevalent. This increased prevalence has provided an opportunity for ultrastructural evaluation of these infectious organisms. Herein is presented a case of intestinal Mycobacterium avium-intracellulare (MAI) in a middle-aged male with uncertain HIV status at diagnosis.

A 56 year-old black male presented to University of South Alabama Medical Center complaining of shortness of breath, anorexia, nausea and vomiting, six month weight loss, and bloody diarrhea. His evaluation was negative for stool ova and parasites and fecal white blood cells. Stool culture and hepatitis viral panel was negative. Iron deficiency anemia and multiple calcified granulomas in both lungs were identified. On his third hospital day, he developed an acute abdomen. At exploratory celiotomy, segmental resection of jejunum and a liver biopsy were performed. Post-operatively the patient's cardiopulmonary status steadily declined and he died three days later.
Fibrinogen Marburg Fibrin Network Structure
Authors: DiOrio JP , Mosesson MW , Hernandez I , Sugo T , Matsuda M
Published: July 2020

Fibrinogen is composed of three pairs of polypeptide chains, termed Aα, Bβ and γ, respectively. Proteolytic conversion of fibrinogen to fibrin by thrombin releases fibrinopeptide A and exposes an N-terminal polymerization site ('EA’) in the central E domain of the molecule. This site interacts with a constitutive complementary site in each outer D domain ('Da’) to drive the molecular assembly process by end-to-middle domain non-covalent ‘Da:EA’ interactions. End-to-end aligned double-stranded fibrils are formed in coordination with another recently described constitutive self-association site (termed ‘D:D’)fhat is situated at the outer end of each D domain. The D:D site contributes to end-to-end molecular alignment of fibrin molecules within each fibril strand. Concomitant branching and lateral fibril associations to form thick fibers, lead to formation of the mature fibrin clot.

Fibrinogen Marburg is a homozygous hypodysfibrinogenemia lacking amino acid residues Aα461- 610 due to a stop codon at position 461 of the Aα chain.
Microscopic Studies of Endospore and Parasporal Crystal In Bacillus Thuringiensis Kurstaki A3-4 From Fermentor
Authors: Feng-Chen KC , Jan XS , Liu BL , Tzeng YM
Published: July 2020

Using microbes for the biological control of pests is progressing very rapidly. Because of the high specificity and none of toxicity to the vertebrates, they become the environmental biopesticides. The most commonly used entomopathogen is Bacillus bacteria, such as B. thuringiensis.Mass culturing of B. thuringiensisin different types of fermentor is experimenting in order to reach the highest yield of endospore and the crystalline endotoxin, the main virulent components for the pesticidal activity.

Bacillus thuringiensisproduces endospore and the parasporal inclusions, Hannay (1953) observed in bacterium B. thuringiensis a mature endospore and a prism-shaped crystal (parasporal crystal).’ The endospore and the endotoxin crystal vary during growth depending upon the availability of nutrient. Glucose concentration in medium has enormous effects on the production of parasporal crystal, B. thuringiensiscan not grow, nor produce parasporal crystal in low concentration of glucose medium. The formation time of the endotoxin crystal also differs in different subspecies.
Low Voltage Field Emission Scanning Electron Microscopy Provides Structural Evidence For Actin-Sized Filaments In Toxoplasma Gondii
Authors: Schatten Heide , Sibley David , Ris Hans
Published: July 2020

The protozoan parasite Toxoplasma gondiiis an obligate intracellular parasite that exhibits gliding and twisting motility during cell locomotion and host cell invasion. By using molecular and genetic approaches it has been determined that actin and myosin are localized beneath the parasite plasma membrane and produce the force for motility and active penetration during host cell invasion. However, structural evidence for actin fibers beneath the plasma membrane is still missing. Recently Chavez et al. demonstrated actin-like filaments in isolated cytoskeletal complexes. Our aproach has been to remove the cell membrane with 0.15% Triton X-100 in cytoskeleton preserving buffer, followed by imaging with low voltage field emission SEM. As seen in Fig. I, we could demonstrate the subpellicle actin network in parasites invading a host cell (arrow). Fig. 2 shows a similar subsurface network of actin filaments in a parasite gliding on glass.
The Lyme Disease Spirochete, Borrelia Burgdorferi, Forms Spheroplasts In the Presence of Spingolipid Analogue Ppmp
Authors: Lubke Lori L , Garon Claude F
Published: July 2020

Lyme disease is the most common arthropod-borne infection in the United States. Over 100,000 cases have been reported to date. The disease is a multisystem disorder with dermatologic, neurologic and rheumatologic manifestations. The causative agent, Borrelia burgdorferi1has been isolated from ticks, animals and humans from around the world and can generally be cultured in the laboratory using BSK-II medium.

While biologically significant concentrations of eukaryotic cell inhibitors such as aphidicolin, ara C, cis platinum, CPX, hydroxyurea, mimosine, nalidixic acid, trioxsalen and boromethyglycine showed little effect on the growth of Borrelia burgdorferiwhen added to BSK-II cultures, PPMP, a spingolipid analogue, showed immediate and profound inhibitory effects when monitored by dark-field microscopy, transmission electron microscopy (TEM), field emission scanning electron microscopy (SEM) and by optical density measurements at 600 mμ. PPMP (dl-thzreo-l-phenyl-2-palmitoylamino-3-morpholino-l-propanol) is known to inhibit the synthesis of spingomyelin in Chinese hamster ovary cells and to inhibit the synthesis of glucosylceramides in a large variety of mammalian cells.
Light and Electron Microscopic Examination of the Vascular Changes After Long Term-Low Dose Cyclosporin-A Treatment
Authors: Aktas R G , Kutlu K
Published: July 2020

Cyclosporin-A(CyA) is a very potent immunosuppressive agent which is widely used in transplantations and autoimmune diseases. The aim of this study was to investigate (i) the vascular changes after long term and low dose CyA treatment, (ii)if Cremophor-EL(the vehicle in the intravenous form of CyA) is responsible from these changes, and (iii) the structural effect of combined therapy with prednisolone on light and electrone microscope level.

Twenty-four female Sprague-Dawley rats were divided into four groups: First group was control. The other three group had daily intraperitoneal injection of 4mg/kg/day CyA for 2.5 months. Second group had oral, third group had intravenous form of this drug while the fourth group had intravenous form with 1 mg/kg/day prednisolone. Biopsy specimens from renal cortex were embedded in paraffin and Araldite for light and electron microscopic examinations.

Light microscopic changes were quite similar in all three experimental groups and confined to arterioles and small arteries: Endothelial cells protruded into the lumen,even seperating from the intimal layer; while some of them were undergoing pyknosis.
A Morphologic Study of Canine Hepatozoonosis: An Emerging Tick-Transmitted Disease
Authors: Cummings CA , Panciera RJ , Ewing SA , Kocan KM
Published: July 2020

Canine hepatozoonosis, an emerging tick-transmitted protozoal disease of dogs in the United States, was first recognized in Texas in 1978. Since 1978, the geographic distribution of the disease has expanded to include Louisiana, Alabama, Georgia, and Oklahoma. The expansion of hepatozoonosis maybe associated with spread of the tick vector, Amblyomma maculatumThe causative agent of North American hepatozoonosis was initially thought to be a particularly virulent strain of Hepatozoon canis,the parasite that causes hepatozoonosis in the Old World. However, because of notable differences between the disease and the morphologic features of asexual and sexual stages of the parasites in the USA and the Old World, the organism responsible for canine hepatozoonosis in North America was designated a new species, Hepatozoon americanumThe clinical course of canine hepatozoonosis in the USA is chronic, progressive, and generally fatal. The disease manifests with intermittent fever, gait abnormalities, marked lethargy, weight loss, muscle wasting, and pain.
Skeletal Muscle Ultrastructural Pathology In Multihormonal Disorder
Authors: Márquez A , Finol HJ , Pulido-Méndez M , Campos de Veitía M
Published: July 2020

Several endocrine disorders with increase or deficiency of hormone production may present a skeletal muscle compromise. Those conditions have been considered as metabolic myopathies. Nevertheless, some pathological abnormalities, mainly microvascular changes and the existence of a cell infiltrate, found in endocrine disorders with an autoimmune origin (primary hipothyroidism, hyperthyroidism associated with Graves disease, diabetes mellitus) have permitted classifing them as inflammatory myopathies. Although muscle pathology in diseases with isolated hormone production alteration has been extensively studied, this investigation has not been realized in patients with abnormalities in several endocrine glands. In this work we report the skeletal muscle ultrastructural pathology in a patient with multihormonal disorder.

A 19 years old male patient presented dwarfism with lack of muscular and sexual development. Plasma levels of thyroxin, Cortisol, growth hormone, testosterone, LH and FSH were low. TSH plasma levels were high.
Diagnosis of Polyoma Virus Infection In Renal Transplant Recipients
Authors: C. King J A , Howell D N , Tucker J A , Lowry R P
Published: July 2020

BK polyoma virus is a 40-45 nm DNA virus that was first identified in the urine of an immunosuppressed patient in 1971. BK virus infection often occurs in childhood and is subclinical. The majority of adults have antibodies to the virus. Asymptomatic viruria, ureteral ulceration, and ureteral stenosis have been described with infection in immunosuppressed patients. Renal graft dysfunction and interstitial nephritis have been associated with BK virus. Differentiation between rejection and infection is important. We report a case of a renal transplant patient with BK polyoma virus infection. This case illustrates the variety of methods that can be used for identification of BK polyoma virus.

The patient, a 52 year old female, presented with an asymptomatic rise in serum creatinine (1.4 to 2.1 mg/dl). Her past medical history was significant for a cadaver kidney transplant two years prior for polycystic kidney disease.
Localization of Inducible Nitric Oxide Synthase In a Rat Model of Silicosis
Authors: Millecchia L , Willard P , Hubbs A , Porter D , Castranova V
Published: July 2020

We are participating in a collaborative project at NIOSH on mechanisms of silicosis, in which rats were exposed to filtered air (control) or silica aerosol of 15 mg/m3 (6 hr/day, 5 days/week), with assays conducted at intervals over a 6 month period. We are especially interested in the role of nitric oxide (NO) in the pathophysiology of lung disease. One source of NO is the alveolar macrophage, known to express the inducible form of nitric oxide synthase (iNOS); we used immunohistochemical techniques to determine whether iNOS is upregulated in alveolar macrophages and other lung sources in response to silica.

Silica-exposed and air control animals were sacrificed after 10, 20, 41, 79, and 116 days of exposure. Formalin fixed, paraffin embedded tissues were cut at 5μm, deparaffinized in xylene and rehydrated. Slides were microwaved in citrate buffer, pH 6.0 for antigen retrieval.2 After blocking endogenous peroxidase in 3% H2O2:Methanol (1:1), slides were placed in 10% BSA for 30 min, then incubated overnight in the primary antibody (Monoclonal anti-iNOS, Transduction Laboratories, N32020, 1:50 dilution)
In Vitro Investigation of the Synthetic Sebum Adsorbing Efficacy of Acrylate Copolymer as an Excipient And In Clinac ™ Oc
Authors: Taylor R W , Smith Christine , White M
Published: July 2020

While sebum provides several functions in the integument, there is considerable interest in the control of excess sebum on the human skin. The primary function of sebum is to lubricate and waterproof the stratum cornenum layer, in addition to preventing hair from becoming brittle. In several cases, the secretion of sebum is inhibited as a result of blockage of the drainage pathway for the sebaceous glands which may result in abnormal skin conduction (1,2). Clinac™ OC (Oil Control) has been developed with a special oil adsorbing polymer, DVB/lsobornyl Methacrylate/Lautyl Methacrylate Copolymer (3). This particular copolymer posses the capacity to adsorb oils because of its high affinity for hydrophobic nonpolar substances. The purpose of this investigation is to show the adsorptive capacity of the acrylate copolymer in Clinac™ OC preparation and in buffer.

The acrylate polymer was incubated in artificial sebum for 4 hrs and 8 hrs at 37 C.
Apoptosis In Experimental Unilateral Abdominal Cryptorchid Testis In Rat
Authors: Al-Bagdadi F , Stout R , Farouqi S , Crawford P , Kearny M , O’Donnell J , Husein S
Published: July 2020

It has been reported that cryptorchidism caused disruption of spermatogenesis that become extensive with time (1). The process of spermatogenesis undergoes spontaneous degeneration in rats, the spermatids degenerate, the primary spermatocytes have been reported to degenerate more commonly (2). Apoptosis has been considered the route for removing sensitive germ cells after short-term experimental cryptorchidism (3). The abdominal heat stress causes cell loss by apoptotic pathway (4). The cellular damage of the experimentally induced cryptorchid adult rat is regulated by local testicular factors in pachytene spermatocyte (5). In this preliminary diagnostic study, we examined the role of the effect of the body temperature on the seminiferous tubule cells in surgically induced unilateral cryptorchid testis at various time periods in rats. This study is to document the extent of the cellular damage at various specified time periods of abdominal retention of the testis.
Angiogenic Remodeling of the Pulmonary Microcirculation
Authors: Schraufnagel D E , Kathula S , Hu F , Michel R P
Published: July 2020

The lung is supplied by pulmonary and bronchial arteries. Unilateral ligation of a main pulmonary artery results in bronchial vascular expansion and new anastomoses between the bronchial and pulmonary circulations. The form and location of this expansion is the subject of this project.

We ligated the left pulmonary of 15 rats and killed 3 rats 1,2,4, 6, and 8 weeks after the ligation. We studied 3 control animals that did not undergo ligation. We cast the vasculature of the lungs with methyl methacrylate and examined both the right and left lungs by light and scanning electron microscopy.

We found that the expansion and anastomoses occurred in and near the bronchovascular bundles and along the pleura, even though the rat pleura is supplied by pulmonary vessels. Near large pulmonary arteries, the junctional and alveolar capillaries were irregular, flattened, and had lateral outbulgings. The diameters varied within short lengths.
Micro Vascularization of the Cerebral Cortex in Frontal and Parietal Lobes of the Rabbit (Oryctolagus Cunniculus)
Authors: Chopard RP , Conegero CI , Watanabe I , Ocaña R
Published: July 2020

In order to warrant the blood supply to the nervous system it is necessary an efficient and intact blood circulation system, where the pattern of vascularization is of fundamental importance. In this way, we intend to demonstrate the tridimensional architecture and the pattern of vascularization in the region of the brain cortex of frontal and parietal lobes. There for, our proposal is to study the microvascularization of the rabbit cortex (Oryctologus cuniculus).The studies about blood irrigation of the brain regions are very important to verify the capilar nets and their relations with intensity of blood flux in specified regions of central nervous system.

The articles about vascularization that uses models obtained by the injection of aloplastic materials whose viscosity is similar to the blood's that allows the difusion until the capilar net was introduced by Murakami (1971). Lametschwandter et al (1984), studied aspects of corrosion technique to microvascular models.
Solid State Conformational Transitions In Peptides Modeling B. Mori Fibroin
Authors: Wilson D , Valluzzi R , Vuong T , Chien S-J , Gido S P , Kaplan D
Published: July 2020

Fibrous proteins are molecules whose secondary structures are their dominant motifs due to their highly repetitive amino acid sequences. Most fibrous proteins have physiological roles as protective, connective or structural materials. Among the fibrous proteins, silks tend to have blocky structures, with crystallizable and amorphous blocks comprised of short, highly repetitive amino acid sequences. In addition, the high glycine content of silks allows them greater conformational variability than most proteins, thus Bombyx morisilk fibroin is typically polymorphic.

The ability of silk fibroin to adopt multiple conformations and crystal structures makes it difficult to obtain corroborating data using multiple characterization techniques. Differences in sample preparation to accommodate different techniques can also affect the resulting sample structure. Reproducible sample preparation was achieved for IR and TEM experiments by rubbing the dried IR sample with a carbon substrate TEM grid to pick up tiny flakes of solidified peptide.
1,2-Diacetylbenzene Neurotoxicity: A Model to Study the Role of Schwann Cells in Maintenance of Axonal Integrity in Toxic States
Authors: Kim MS , Kayton R , Muñiz J , Austin DR , Spencer PS , Sabri MI
Published: July 2020

Twenty-five years ago, one of us postulated the existence of a dynamic mechanism for the selective glial sequestration and removal of effete organelles (mitochondria, vesicles, dense bodies) and leprous bacilli from intact axons of myelinated nerve fibers. A thin cytoplasmic sheet derived from the adaxonal Schwann cell or oligodendrocyte invaginates the axon surface, corralls pockets of axoplasm containing the organelles, and removes the cytoplasmic material by phagocytosis (1). This radical proposal was based on inferences drawn from the seemingly logical sequential assembly of transmission electron micrographs depicting static images of mammalian myelinated nerve fibers in normal and pathologic states. Direct evidence to support this proposal came from the use of light/fluorescence, confocal laser, and/or electron microscopy to trace the fate of fast transported radiolabel injected intraspinally, of red-fluorescent latex nanospheres taken up at a sciatic nerve crush site, and of intramuscularly injected horseradish peroxidase endocytosed by intact synaptic terminals (2,3).
Transmission Of Borreua Hermsii, The Agent Of Relapsing Fever, By The Tick Vector Ornithodoros Hermsi
Authors: Fischer Elizabeth R , Schwan Tom G
Published: July 2020

Relapsing fever, a disease characterized by recurrent episodes of high fevers, is caused by geographically distinct spirochetes of the genus Borrelia,transmitted by ticks of the genus Ornithodoros. In the Northwestern United States, the soft tick Ornithodoros hermsi has been identified as the vector for the spirochete Borrelia hermsii. The life cycle of O.hermsi includes larval and multiple nymphal stages prior to full maturation into an adult male or female (Fig.1). Progression into each stage requires a blood-meal typically provided by squirrels and chipmunks, and incidentally humans. Feeding is rapid, lasting 10-60 minutes, and during this time an infected tick can transmit the agent of relapsing fever, B. hermsii. Following ingestion, spirochetes are initially found in the tick midgut. Within 1-3 weeks, they are found in other organs, including the central ganglion and salivary glands. Since saliva is the primary mode of transmission of these bacteria during tick feeding, we assessed by electron microscopy the structural and functional relationships between the spirochetes and the salivary glands.
Imaging Molecular Targeting In Living Neural Cultures
Authors: Wallace Christopher S , Silverman Michael A , Burack Michelle A , Lochner Janis E , Allen Richard G , Banker Gary
Published: July 2020

Recent technical advances in the ability to attach an endogenously fluorescent protein sequence—i.e., green fluorescent protein or GFP and its derivatives--to any protein of experimental interest promises to mark a new era of progress in the study of protein targeting. Bringing these new tools to bear on neurons of the central nervous system has been challenging, however, because they have a very complex structure and are relatively difficult to transfect because they are post-mitotic.

We use two cell culture approaches to characterize protein trafficking within neurons of the central nervous system in vitro. The first is a dissociated culture of hippocampal neurons from embryonic (El8) rats which is especially suited to analysis by conventional light microscopy because these neurons are grown on glass coverslips at low density. Neurons cultured in this way develop a morphology comparable to that seen in vivo and permit the establishment of axons and dendrites to be analyzed by time-lapse microscopy.
Pericyte Ultrastructural Alterations In The Gastrointestinal Adenocarcinomas Microvasculature
Authors: Tonino P , Finol HJ , Sosa L , Hidalgo C
Published: July 2020

Pericytes are cells of mesodermal origin that intimately surround most types of blood capillaries as well as postcapillary venules and precapillary arterioles (smooth muscle cells are found in the walls of larger vessels). Although abnormalities of capillary endothelial cells have been described in diseases such as diabetes, arterial hypertension, autoimmune inflammatory myopathies and also in the paraneoplastic phenomenon, much less is known about morphology of pericytes and its implications in the microvascular structure in cancers, particularly those arising in the gastrointestinal tract. In this work we report the pericyte ultrastructural pathology in human gastrointestinal adenocarcinomas.

Surgically resected specimens from areas of tumor center and periphery were obtained from thirteen patients (seven females and six males) between 44 and 76 years of age (mean 61.92 years), with a histopathological diagnosis of gastrointestinal adenocarcinoma. Immediately after resection, tissue samples were processed by routine transmission electron microscopy techniques and observed in Hitachi H-500 and H-7100 electron microscopes.
Scripted Image Enhancement / Analysis Using Adobe® Photoshop® With Ip Tools® Plug-Ins
Authors: Underwood R , Muffley L , Predd H , Piepkorn M , Olerud J
Published: July 2020

The Derm Imaging Center uses various light and electron microscopic techniques to determine meaningful morphologic differences in skin samples received from multiple investigators. Qualitative comparisons required laborious hand measurements, which, in time gave way to computer assisted image capture, enhancement and analysis. The ability to attach a numerical value to a morphologic observation has made quantification an expected component of the experimental results. Laboratory personnel are now spending more time in front of computers than microscopes. This fact prompted a reevaluation of our current methods resulting in a faster, user-friendly computer assisted imaging system.

One software program that has become ubiquitous within the field of scientific imaging is Adobe® Photoshop®. Although a multitude of different image capture and analysis software programs are in use, a version of Photoshop® can invariably be found residing in most laboratories involved in imaging. A disadvantage of many image analysis software programs is the lack of image enhancement capability that we have grown to know and love within the Photoshop® environment.
Aquatic Surface Film Organisms Collected On Glass Substrates For Evaluation By Scanning Electron Microscopy.
Authors: R. W. Smith
Published: July 2020

Organisms found at the Air-Water Interface (AWI) are often difficult to collect and usually show distortion upon collection and fixation by traditional methods. Furthermore, the spatial relations between the organisms and the complexity of their biofilm community is disrupted or destroyed by collection methods that involve bulk water collection, filtration, settling or rotating drums. Samples shown here were collected on the Tualatin River, Oregon, a eutrophic rural/suburban stream with welldeveloped Aquatic Surface Films (ASF or Microlayers) in quiet waters.

Here, I describe a simple method of collection for Aquatic Surface Films (Microlayers), by drawing a glass substrate slowly through the surface film, allowing both organic chemicals and small organisms to adhere to the surface of the glass. This is similar to the collection of a Langmuir-Blodgett film, and it has been proposed that chemical and biological films at the surface might allow this type of collection.
Histological And Ultrastructural Changes In Leaves Of Resistant And Susceptible Chickpea Cultivars To Ascochyta Rabiei (Pass.) Labr
Authors: Ilarslan H , Dolar BFS
Published: July 2020

The Ascochyta blight caused by Ascochyta rabiei ( Pass.) Labr. is a serious foliar fungal disease of chickpea (Cicer arientinum L.). The histo- and cytopathological examination of hostpathogen interactions was conducted in resistant ( ELC-195) and susceptible (Canitez-87) cultivars of chickpea at 3, 5, 7 days after inoculation with A. rabiei. Several histological studies have been made with A. Rabiei. No ultrastructural studies comparing the resistant and susceptible reactions of chickpea to A. rabiei have been reported.

The hypersensitive response (HR) is a very common reaction in resistant chickpea plants challenged with A. Rabiei. The FfR has also been associated with defence reactions which is phytoalexin synthesis. Phytoalexins are compounds, synthesised in host plant cells, after infection, which have antimicrobial properties. Fligh concentrations are often found in nearby necrotic cells which prevents further growth of the A. Rabiei in resistance chickpea.

A. rabiei produce typical appressorium formation for cuticle penetration but stomata penetration have been observed in some micrographs (Fig.l).