Biology Commons^™

Immunological Pathogenesis Of Endolymphatic Hydrops And Its Relation To Meniere's Disease, S. Tomiyama, T. Yagi, M. Sakagami, K. Fukazawa

Scanning Microscopy

This study was designed to investigate an immunologically induced endolymphatic hydrops (ELH) and to focus on the issue of its pathogenesis in relation to Meniere's disease. The time course of ELH was evaluated by light microscopy in a 2-hour to 7-month period following direct antigen challenge to the endolymphatic sac (ELS) in systemically pre-sensitized guinea pigs. ELH began to appear in the vestibule and the basal turn 5-7 hours after inner ear challenge and developed gradually. During the interval from the second day to the first week, ELH rapidly developed in all the cochlear turns and reached a maximum size. …

An Energy Dependent Model For Type I Magnetic Contrast In The Scanning Electron Microscope, W. K. Chim, D. S. H. Chan, J. C. H. Phang, T. S. Low, S. Thirumalai

Scanning Microscopy

The modelling of the magnetic contrast phenomenon in the scanning electron microscope (SEM) is important in understanding the physics of the contrast mechanism and the associated signal detection. In this paper, we report an improved analytical model for Type I magnetic contrast calculations using an approximate form of the Chung and Everhart secondary electron (SE) energy distribution. Previous studies have neglected this factor by assuming a mono-energetic model in order to simplify the calculations. This new model can be used to study different material specimens by appropriate choice of the work function and field-distance integral. The effect of energy filtering …

Evaluation Of Erbium:Yag Laser Radiation Of Hard Dental Tissues: Analysis Of Temperature Changes, Depth Of Cuts And Structural Effects, A. F. Paghdiwala, T. K. Vaidyanathan, M. F. Paghdiwala

Scanning Microscopy

Temperature elevations, depths of cuts and structural changes produced by 2.94 micron pulsed Erbium:YAG laser radiation of hard dental tissues, at different power levels and exposure times of the laser, were studied. The depth of cut produced was found to vary significantly as a function of power level and exposure time on dry teeth. The mean temperature rise with laser radiation was also influenced both by power level and time of exposure. The effect of water flow on the teeth during laser exposure was evaluated; the results indicate that the ablation efficiency was better, temperature elevations lower and structural changes …

Scanning Electron Microscopy Of Age-Related Changes In The C57bl/6j Mouse Cochlea, Kunihiro Mizuta, Osamu Nozawa, Hirofumi Morita, Tomoyuki Hoshino

Scanning Microscopy

Hair cells and nerve fibers inside the organ of Corti of the C57BL/6J mouse, which is known as the precocious presbycusis model, were studied using the scanning electron microscope. For this study, we used thick serial sections cut from celloidin blocks.

In the 5-week-old mice, hair cell loss was not seen. The upper tunnel radial fibers crossed the upper part of the tunnel of Corti and entered the Nuel's space between the outer pillar cells. The fibers varied in diameter and showed many varicosities. The basilar fibers emerged into the tunnel of Corti beneath the upper tunnel radial fibers …

Sample Preparation Techniques For Conventional And High Resolution Scanning Electron Microscopy Of The Central Nervous System. The Cerebellum As A Model, Orlando J. Castejon

Scanning Microscopy

In the present paper some basic sample preparation techniques for scanning electron microscopy of nervous tissue are described. These basic preparative methods include conventional scanning electron microscopy or slicing technique, ethanol-cryofracturing technique, freeze-fracture method using either liquid nitrogen (slow freezing) or Freon 22 cooled by liquid nitrogen (fast freezing), improved freeze-fracture method with delicate specimen preparation and chromium coating, ultrasonic microdissection, and "creative tearing" technique. Some basic principles, advantages and limitations are critically considered. In addition, some specific applications in neurobiological research are reported. Emphasis is placed upon understanding the sources and nature of artifacts that are likely to be …

A Review Of New Concepts In Renal Stone Research, L. C. Cao, E. R. Boevé, W. C. De Bruijn, W. G. Robertson, F. H. Schröder

Scanning Microscopy

Clinical and basic research in the field of urolithiasis has developed rapidly in recent years. Progress in extracorporeal shock wave lithotripsy (ESWL) and percutaneous nephrolithotomy (PNL) has brought about a revolution in the surgical treatment of urolithiasis and research at the cellular and molecular level is now expanding. In spite of these advances, however, clinical treatment of urolithiasis remains far from satisfactory. Stone recurrence in many patients cannot be predicted and is beyond control of urologists mainly because the mechanisms of stone formation are still not fully understood. It is necessary to study the process of stone formation more intensely …

Analysis Of Synthetic Dnas And Dna-Protamine Complexes With The Scanning Tunneling Microscope, Michael J. Allen, Robert J. Tench, Joe A. Mazrimas, Mehdi Balooch, Wigbert J. Siekhaus, Rod Balhorn

Scanning Microscopy

Three duplex DNAs 22, 47, and 100 base-pairs in length have been imaged with the scanning tunneling microscope (STM) after deposition on highly oriented pyrolytic graphite (HOPG). Images of the 47 base-pair (bp) molecules are resolved sufficiently to identify the two phosphodiester strands, the direction of helical coiling (this molecule contains three turns of left-handed helix), and single-stranded ends. Length measurements indicate that all three DNA sequences have adopted an "A-like" conformation. DNA-protamine complexes were also prepared and imaged under similar conditions. Length measurements of the complexes demonstrate that the binding of bull protamine 1 to the 47-mer stabilizes the …

Specimen Preparation And Chamber For Confocal Microscopy Of The Ex Vivo Eye, Barry R. Masters

Scanning Microscopy

A chamber is described for maintaining the mechanical and physiological stability of the ex vivo eye during observation with confocal microscopy. The mechanical stability is provided by a plastic ring situated on the limbal region of the eye. The ring and supporting chamber are designed to reduce mechanical motion of the specimen. The ring and chamber size vary with the species and size of the eye under examination. The physiological stability over a period of approximately one hour is provided by immersing the eye in a bicarbonate Ringer's solution that is exchanged every five minutes. This fluid exchange is made …

Scanning Electron Microscopy Of 2,8-Dihydroxyadenine Crystals And Stones, P. Winter, A. Hesse, K. Klocke, R. M. Schaefer

Scanning Microscopy

The lack of purine salvage enzyme, adenine phosphoribosyltransferase (APRT), leads to 2,8-dihydroxyadenine stone formation and/or crystalluria because it is insoluble in urine. Urolithiasis composed of 2,8-dihydroxyadenine is not only formed in a complete defect of APRT, but also in a partial deficiency of this enzyme. The defect is inherited as an autosomal recessive trait, the homozygous state is associated with high urinary levels of 2,8-dihydroxyadenine and with crystalluria, calculus formation, and potential nephrotoxicity. Determination of the APRT activity will facilitate quantification of the enzyme deficiency and elucidation of the hereditary history. 2,8-dihydroxyadenine excretion in the 24-hour urine and its circadian …

Protein Inhibitors Of Calcium Salt Crystal Growth In Saliva, Bile And Pancreatic Juice, J. M. Verdier, B. Dussol, Y. Berland, J. C. Dagorn

Scanning Microscopy

The control of the formation of crystals in biological fluids is one of the most exciting field of research involving both organic and biochemical areas. Many organisms have evolved mechanisms which minimize or avoid the effects of nucleation and crystal growth formation. One of the most important mechanism is the interaction of specific proteins, called inhibitors, with crystals which alters their habits and leads to their elimination. This article, focused on saliva, pancreatic juice and bile, reviews our present knowledge on the structure-function relationships existing between these proteins and their ability to inhibit the growth of different calcium salt crystals.

Energy-Filtering Transmission Electron Microscopy Of Biological Specimens, W. C. De Bruijn, C. W. J. Sorber, E. S. Gelsema, A. L. D. Beckers, J. F. Jongkind

Scanning Microscopy

By energy-filtering transmission electron microscopy (EFTEM) electrons can be separated by their energy losses. An electron-energy filter, added to the microscope column allows the measurement of the energy distribution of transmitted electrons that have lost energy (< 2,000 eV, with an energy resolution of ~ 1 eV). These filtered electrons, recorded either as a spectrum or as an image, are composed of two parts superimposed on top of each other: (a) the unspecific energy-loss population (= the continuum) and (b) the specific element-related energy-loss population (= the edges). At the edges, electron data in spectra and images are mathematically processed, to obtain the desired element-related net-intensity values or images. These data are related to the total transmitted electron intensity, from the zero-and low-loss spectral region giving the relative spectral-or image intensity ratios (^SR*_x, ^IR*_x), which can be related to the element concentration. The acquisition of the zero-loss and low-loss data is hampered by the restricted dynamic range of the TV camera. By improvements through the introduction of calibrated attenuation filters in the optical path to the TV-camera, more reliable values for ^SR*_x and ^IR*_x can …

A Cationic Protein From A Urate-Calcium Oxalate Stone: Isolation And Purification Of A Shared Protein, J. P. Binette, M. B. Binette

Scanning Microscopy

A protein extracted from a urate - calcium oxalate stone by electrodialysis is also excreted in the urine which served as the source material for its purification by FPLC after separation on an ACA44 column. It has an amino acid composition appropriate for a cationic protein. One peptide obtained by cyanogen bromide cleavage has significant (approximately 60%) homology with CD59 protein (protectin). Both proteins have wide distribution, the unknown having been found in bile, cholesterol gallstones, and the wall of the aorta. However, the two proteins appear to be immunologically different.

Bcg Cell Imaging Using Scanning Probe Microscopy, Antonio A. Garcia, William C. Pettigrew, John Graham

Scanning Microscopy

Scanning tunneling microscopy (STM) and atomic force microscopy (AFM) were used to obtain images of the surface of whole, intact BCG (bacille Calmette Guerin, a mycobacterium) cells in air and under solution by immobilizing the cells onto glass slides (AFM only) or highly oriented pyrolytic graphite. The technique used for AFM imaging involved depositing a submonolayer of cells under a centrifugal force followed by fixation/dehydration using polar organic solvents. AFM images agree well with images from light and electron microscopy and showed large numbers of BCG cells in their distinctive cord arrangement. The AFM also proved useful for identifying extracellular …

Absence Of A Transcellular Oxalate Transport Mechanism In Llc-Pk1 And Mdck Cells Cultured On Porous Supports, C. F. Verkoelen, J. C. Romijn, W. C. De Bruijn, E. R. Boevé, L. C. Cao, F. H. Schröder

Scanning Microscopy

Transepithelial oxalate transport across polarized monolayers of LLC-PK₁ cells, grown on collagen-coated microporous membranes in Transwell culture chambers, was studied in double-label experiments using [¹⁴C]-oxalate together with [³H]-D-mannitol as an extracellular marker. The [¹⁴C]-labeled glucose analog α-methyl-glucoside (α-MG) was used as functional marker for active proximal tubular sugar transport. Cellular uptake of oxalate and α-MG at both the apical and basolateral plasma membrane was determined. When added to the upper compartment, α-MG was actively taken up at the apical membrane, directed through the cells to the basolateral membrane and transported to the lower …

Comparative Aspects Of Splenic Microcirculatory Pathways In Mammals: The Region Bordering The White Pulp, E. E. Schmidt, I. C. Macdonald, A. C. Groom

Scanning Microscopy

Splenic microcorrosion casts prepared using minimal volumes of material show that most of the flow passes through the region bordering the white pulp. However, the nature of these microcirculatory pathways has received little attention. We have studied these in dog, cat, rat, mouse, and normal versus diseased human spleens. In all 5 species, a marginal sinus (MS) of anastomosing vascular spaces 5-10 μm thick lies between the white pulp and marginal zone (MZ). The morphology differs between species and the MS is absent in immune thrombocytopenia. The MS fills by circumferential flow before blood passes outward to the MZ. Many …

Studies On Structure Of Calcium Oxalate Monohydrate Renal Papillary Calculi. Mechanism Of Formation, F. Grases, A. Costa-Bauzá, A. Conte

Scanning Microscopy

A scanning electron microscopy study of the ultrastructure of 18 calcium oxalate monohydrate papillary calculi was performed with the purpose of establishing the main steps in calculus formation. It is concluded that these calculi originate in a "core" located near the central part of the calculus. Significant quantities of organic matter as well as calcium phosphates can be found in the "core" and at the surface of adhesion to the papilla and, in some cases, fibers and calcified tubules can also be found in the contact zone. In no case did this material affect the crystalline structure of the calculi, …

Casting With Mercox-Methylmethacrylic Acid Mixtures Causes Plastic Sheets On Elastic Arteries. A Scanning And Transmission Electron Microscopic Study, Seyedhossein Aharinejad, Peter Böck

Scanning Microscopy

Lungs and systemic vessels of rats were cast with Mercox, both undiluted and diluted with monomeric methylmethycrylate (MMA; v:v/4:1), and studied by scanning electron microscopy (SEM). A sheet, less than 5 μm thick, surrounded the surface of cast pulmonary arteries and the aorta, when using diluted Mercox. This envelope was absent when casts were prepared with undiluted Mercox. Transmission electron microscopy (TEM) of unmacerated cast arteries showed all constituents of the vascular wall. Sections of thoroughly macerated vascular casts, however, still showed elastic lamellae in the vascular wall region, whereas muscular components and endothelial lining were completely digested. It is …

Morphological And Histochemical Changes In Intercellular Junctional Complexes In Epithelial Cells Of Mouse Small Intestine Upon X-Irradiation: Changes Of Ruthenium Red Permeability And Calcium Content, Z. Somosy, J. Kovács, L. Siklós, G. J. Köteles

Scanning Microscopy

Changes of calcium-content and permeability of tight junction following X-irradiation were investigated in mouse intestinal epithelial cells by electron microscopy. In the control animals the lower parts of tight junctional area as well as the other junctional elements and the intercellular space are labeled by pyroantimonate precipitates, which contain calcium as revealed by electron spectroscopy and electron energy loss spectrometry. X-irradiation, parallel with morphological changes, lead to rapid decrease of pyroantimonate precipitable calcium content and increase of the permeability of tight junctions indicated by the penetration of ruthenium red into the intercellular space. These changes were readily reversible following 0,5 …

Non-Equilibrium Surface Diffusion Measurements In Systems With Interactions, M. C. Tringides, K. R. Roos, A. Jesina, J. Haas, P. Levenberg

Scanning Microscopy

Diffusion in surface overlayers with adsorbate-adsorbate interactions is described in terms of coverage-dependent diffusion coefficients. The measured phenomenological Arrhenius parameters (activation energy and prefactor) depend on the initial configuration of the system. Since different experimental methods probe the system in different states, the measured diffusion coefficients depend on the method used. Experimental results demonstrating this dependence are presented for O/W(110) -p(2x1) + p(2x2) and Ag/Si(111) -√3 x √3 R30°. They were measured during the evolution of the system to attain a new equilibrium state of different symmetry. In addition, simulations on lattice gas models with interactions, modeling …

Electron Beam Induced Current Studies Of Defect Induced Conductivity Inversion, Z. J. Radzimski, A. Buczkowski, T. Q. Zhou, C. Dubé, G. A. Rozgonyi

Scanning Microscopy

Defect induced inversion of conductivity type was studied both at the surface and at a network of interfacially confined misfit dislocations in heteroepitaxial Si(Ge) on Si structures. The inversion was achieved by controlled contamination with Au and Ni metallic impurities introduced by diffusion from backside evaporated layers. A theoretical explanation of the defect electrical activity and the inversion effect is presented, along with temperature dependent beam induced current observations.

Scanning Electron Microscopy Observation Of The Voltage Contrast Image Of The Ferroelectric Domain Structure In The Linbo3 Crystal, D. V. Roshchupkin, M. Brunel

Scanning Microscopy

This paper reports a scanning electron microscopy study of the formation of the voltage contrast image of the ferroelectric domain structure in the LiNbO₃ crystal. We investigated the formation of the pyroelectric voltage contrast image of the regular domain structure. For our experiment, we used ZY cut of a LiNbO₃ crystal which had a regular domain structure with a domain width of -55 μm. The regular domain structure in the LiNbO₃ crystal was formed by the method of thermo-electrical treatment after growth. The pyroelectric voltage contrast image of the regular domain structure in the scanning electron microscope …

Analysis Of Heavy Metals In Mouse Uterine Secretion By X-Ray Microanalysis, Zhengzhu Jin, B. Ove Nilsson

Scanning Microscopy

A method for the detection of heavy metal ions in the uterine secretion of the mouse was tested. Mice received an intravenous injection of lead, and beads of an analytical grade resin, Chelex 100, were deposited in the uterine lumen to absorb heavy metals present in the secretion. X-ray microanalysis of the flushed beads showed that lead was present in a dose-related way in the uterine secretion of mice that had received 0.05, 0.1, or 0.15 mg lead per g body weight. Thus, the technique allows quantitative analysis of lead in the uterine secretion. The amount of lead present in …

Use Of Ultra-Thin Window Detectors For Biological Microanalysis, A. T. Marshall, A. Patak

Scanning Microscopy

Films and bulk samples of Nylon, gelatin, Makrofol, epoxy resin, aminoplastic resin and sodium acetate have been used as models of biological samples. It is shown that the use of ultrathin window (UTW) detectors in scanning transmission and scanning electron microsopes permits the quantitative analysis of light elements, yielding a total element analysis with hydrogen estimated by difference or "guesstimated".

Comparison with known concentrations or concentrations obtained by chemical analysis shows that X-ray microanalysis of sections by the peak to continuum ratio model and bulk samples by the φ(pz) model gives sufficiently accurate results for biological purposes. It …

Hyperplasia And Fluid Accumulation In Epithelial Cyst Formation And Growth, Andrew P. Evan, James A. Mcateer, Kenneth D. Gardner Jr.

Scanning Microscopy

Epithelial cysts may develop in virtually any epithelium. All cysts, regardless of their origins, are characterized by epithelial hyperplasia and fluid accumulation. Additional features may include tubular atrophy, basement membrane alterations and association with inflammatory cells. In spite of the intense research effort in recent years directed at uncovering the cellular mechanisms of cyst development and growth, we still do not know the primary events that lead to cyst formation. However, there are at least three candidate mechanisms. These include: 1) increased cell proliferation (epithelial hyperplasia) in the cyst wall, 2) net fluid accumulation in the cyst cavity and 3) …

Evaluation Of The Use Of Tannic Acid In Preparation Of The Rabbit Knee Meniscus For Scanning Electron Microscopy, Daniel Levanon, Haim Stein

Scanning Microscopy

The femoral faces of medial and lateral menisci of the rabbit knee were structurally reinforced with tannic acid and studied using the scanning electron microscope. Significant improvement in preservation of the meniscal surfaces, as compared to previous studies, was brought about by the structural reinforcement technique. Menisci, although detached from tibial plateaux, retained well their shape, dimensions, and microarchitecture. Differences in surface morphology between medial and lateral menisci and between longitudinal sectors on menisci were recorded. Appearances of surface irregularities were reduced to a very low level, and the possibility that this minimum exists in situ is forwarded.

Analysis Of Early Hard Tissue Formation In Dentine By Energy Dispersive X-Ray Microanalysis And Energy-Filtering Transmission Electron Microscopy, Hans-Peter Wiesmann, Ulrich Plate, Hans-Jürgen Höhling, Rudolf H. Barckhaus, Karl Zierold

Scanning Microscopy

Thin cryosections and sections of embedded tissue were prepared from dentine of cryofixed rat incisors. Energy dispersive X-ray microanalysis (EDX) and electron energy-loss spectroscopy (EELS) have been applied to study the calcium and phosphorus distribution in predentine of these incisors. A small enrichment of calcium and phosphorus was found in the predentine zone near the dentine border.

Element distributions were correlated with analyses of the early crystal formation in dentine. These investigations were carried out by parallel applications of electron spectroscopic diffraction (ESD) and electron spectroscopic imaging (ESI) using zero-loss filtering. It was found that the earliest crystal formations already …

Microvascular System Of The Human Fetal Inner Ear: A Scanning Electron Microscopic Study Of Corrosion Casts, A. J. Miodoński, J. Gorczyca, M. Nowogrodzka-Zagórska, J. A. Litwin, J. Składzień

Scanning Microscopy

The vascular system of the inner ear was investigated in 18-21 weeks old human fetuses, using the corrosion cast technique in scanning electron microscopy. At that developmental stage, vascularization of the cochlea and semicircular canals shows a pattern very similar to that described for adults. The most important differences which can be regarded as fetal features include: (1) denser limbus vessels, (2) the marginal vessels of the spiral lamina appearing as irregular network which shows a less clear arcade-like arrangement, (3) some radiating arterioles of the spiral lamina and marginal vessels possessing connections with the vascular system of the external …

Degeneration And Reorganization Of Vestibular Epithelia After Local Aminoglycoside Application In The Mammalian Inner Ear, J. Dupont, A. Guilhaume, J. -M. Aran

Scanning Microscopy

The development of degeneration of vestibular end organs and their possible reorganization have been observed over a 2 year period after local application of sisomicin in the inner ear using scanning electron microscopy (SEM). Degeneration of stereocilia took place as early as 5 days after the treatment in the utricule, the saccule and the cristae. At 10 days, almost the entire surface of these sensory epithelia presented a smooth aspect without specific structure. However, after 15 days, an epithelial reorganization developed with clear limits between cells. At 25 days, systematic kinociliary structures were observed at the apical surface of the …

Improved Tissue Corrosion Of Vascular Casts: A Quantitative Filtration Method Used To Compare Tissue Corrosion In Various Concentrations Of Sodium And Potassium Hydroxide, Paul A. Sims, Ralph M. Albrecht

Scanning Microscopy

In this study, we compare weights of filter retained material (11 μm particle retention) after solubilization and filtration of unfixed, un-perfused tissue (fat, liver and trachea) in sodium and potassium hydroxide (1% , 5%, 10% and 20% weight/volume, w/v) at 8, 24 and 48 hour time points at 45°C. Three detergents [1% Triton-X-100 (volume/volume, v/v), 1% 7X (v/v), 1% Terg-A-Zyme (w/v)] used in combination with hydroxide were evaluated for use in solubilizing fat. Additionally, vascular casts from mouse kidneys were corroded to test the practical effectiveness of corroding solutions on resin infused tissue.

Five percent KOH for eight hours proved …

Microsporum Canis Scalp Ringworm: Its Primary Or Secondary Ectothrix Character, Hester F. Vismer

Scanning Microscopy

This study supports the view that, in cases of tinea capitis due to a Microsporum canis infection, ectothrix arthroconidium formation is extrapilary and arises from intrapilary hyphae. The hyphae of M. canis perforate and digest the hair cuticle to alter its appearance from a normally identifiable structure of imbricated cells with a distal free border, to a grossly altered and pathological layer. Conidium production mainly takes place outside the hair shaft and forms thick clusters between the cuticular tiles. Finally, a shaft of conidia is formed around the hair. The cuticular covering of such a conidium sheath belongs to the …