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At least 721 records · Page 40Linked to original sources
PubMed2004

[Morphologic characteristics of cornea in Fuchs endothelial dystrophy observed by confocal microscopy].

OBJECTIVE: To analyze the image of corneas with Fuchs endothelial dystrophy using confocal microscopy in vivo. METHODS: Central corneas of 38 eyes (19 patients aged 33 approximately 76 years) were examined using scanning slit confocal microscopy in vivo after being diagnosed with Fuchs endothelial dystrophy. They were divided into two groups namely symptomatic (19 eyes) and asymptomatic (19 eyes). The control group comprised of 30 normal eyes. The images were analyzed visually for morphology of corneas and the densities of cells, as well as the diameter of the guttae and the corneal nerves were counted by NAVIS software. RESULTS: (1) In the symptomatic groups, confocal microscopy revealed guttae in 19 eyes. The diameter of the guttae ranged from 20 to 60 micro m. The density of endothelial cells was statistically significant compared with the control group (t = 18.74, P < 0.01). Descemet's membrane was thickened in 9 eyes. Dark bands 6.0 approximately 10.8 micro m in diameter were detected in 14 eyes. All eyes showed a diffuse increased light reflection in the stroma.17 eyes exhibited an abnormal Bowman's layer: multiple focal bright reflection. 10 eyes revealed normal corneal nerves. The differences between posterior and anterior keratocyte densities in the control and study groups were not statistically significantly different (t = 0.854, 1.173; P = 0.38, 0.24 respectively). (2) In the asymptomatic groups, less number of guttae could be seen in the endothelial layer. The diameter of the guttae was 15 approximately 40 micro m. The densities of endothelial cells were not significantly different compared with control group (t = 1.998, P = 0.053). Other layers of the cornea exhibited no other abnormal phenomenon. The densities of endothelial cells between symptomatic and asymptomatic groups were statistically significantly different (t = 8.352, P < 0.01). CONCLUSIONS: Morphologic characteristics of cornea are observed by confocal microscopy in Chinese patients with Fuchs endothelial dystrophy. Preliminary results demonstrate that there is no significant difference between Chinese and western patients. Confocal microscopy allows to diagnose Fuchs dystrophy and visualize endothelial cells within the swollen cornea. And it is especially useful for patients whose endothelial cells can not be seen with non-contact specular microscopy.

Adult↗
PubMed2004

Comparison of optimal malarial test with light microscopy for the diagnosis of malaria.

OBJECTIVE: To evaluate the efficacy of a parasite lactate dehydrogenase-based immunochromatographic antigen detection assay (optimal) against conventional light microscopy in the diagnosis of malaria at Military Hospital, Rawalpindi and Department of Pathology Army Medical College Rawalpindi from August to October 2002 in patients reporting sick with history suggestive of malaria. METHODS: The blood samples were collected from 215 patients reporting with symptoms suggestive of malaria. Thick and thin blood films were prepared, stained with Leishman's stain and examined by light microscopy for the presence of malarial parasites. Parasitaemia was estimated on all positive slides. All samples were tested for presence of malarial parasite by optimal dipstick method according to the manufacturer's instructions. RESULTS: A total of 215 cases were studied. Malarial parasites were visualized in 98 (45.5%) cases with light microscopy. Optimal test revealed 93 (43.2%) of these samples as positive. Microscopy showed 61 out of 98 positive cases to be P. vivax and 37 P. falciparum. The Optimal dipstick method revealed that 58 out of 93 were positive for P. vivax and 35 positive for P. falciparum. These results demonstrated that Optimal had sensitivities of 95% and 94.5% for P. vivax and P. falciparum respectively. It has 100% specificity for both malarial species, when compared to conventional microscopy. CONCLUSION: Optimal test showed excellent correlation with microscopy in the diagnosis of P. vivax and P. falciparum. It is expensive but it has an advantage of being simple, rapid and effective test in the diagnosis of malaria especially where well trained microscopists are not available or work load is too high.

Animals↗
PubMed2006

[In vivo fluorescent microscopy of the liver microcirculation after embolization with a newly developed trans-proper hepatic arterial infusion animal model].

OBJECTIVE: To evaluate the value of the in vivo fluorescent microscopy in studying the changes of liver microcirculation after embolization with a newly developed animal model for tans-proper hepatic arterial infusion, and to summarize the method of making this animal model. METHODS: Ten Sprague-Dawley rats were used in this study. After a midline abdominal incision, microcatheter was placed into the gastroduodenal artery (GDA). The tip of the catheter was placed facing the orifice of proper hepatic artery. After infusions of 0.02%, 0.1%, 0.5%, 1% fluorescent sodium, fluorescent microscopy was used to evaluate the liver microcirculation. The image quality was then accessed. Embolization was obtained by injections of Lipiodol and Degradable Starch Microspheres (DSM) from the microcatheter. Corresponding changes of the liver microcirculation was evaluated by fluorescent microscopy. RESULTS: From the 10 rats, 8 animal models were successfully established. The microcirculation of the liver could be clearly visualized by the fluorescent microscopy. The optimal concentration of fluorescent sodium was 0.1%. The direct and indirect phenomena caused by embolic material could be evaluated by fluorescent microscopy. CONCLUSION: Fluorescent microscopy with the corresponding Trans-hepatic arterial infusion animal model is a valuable method to evaluate the microcirculation of the liver and can be used for the evaluation of changes of liver microcirculation caused by embolization material.

Animals↗
PubMed1983

[Scanning microscopy study of the corneal epithelium. Relation of various aspects to the lacrimal film].

Cells of the superficial layer of the corneal epithelium demonstrate differences in luminosity on scanning electron microscopy which has led to their classification as clear, intermediate or dark cells, differences attributed to varying amounts of surface microvillosities. Evidence is provided confirming that differences between cells is not due to artefacts during preparation or observation of specimens. On the other hand, this technique cannot demonstrate whether different evolutory stages of the same cell are involved. Scanning microscopy cannot confirm a single evolutory epithelial cell are involved. Scanning microscopy cannot confirm a single evolutory epithelial cell cycle from the position of the cell in relation to adjacent desquamating cells, or the study of the cell nuclei. Nor can a satisfactory response to the problem be supplied by studying mucosubstances deposited by the lacrimal film on the surface of the epithelium, either by optical microscopy or after scanning electron microscopy with or without washing with acetylcysteine. The presence of superficial epithelial cells of different appearances on scanning microscopy must be due to variations in the amount of glycocalix, the mucus film adsorbed onto the cell surface.

Animals↗
PubMed1993

[Surface microscopy of pigmented cutaneous tumors].

BACKGROUND: Clinical guidelines for the diagnosis of pigmented lesions of the skin are not always reliable. Especially the differential diagnosis between benign dysplastic nevi (Clark's nevi) and early melanomas, as well as between melanocytic and nonmelanocytic skin tumors (seborrheic keratoses, pigmented basal cell carcinomas and angiokeratomas) is often difficult. OBJECTIVE: Surface microscopy, which is performed today under various synonyms (dermoscopy, dermatoscopy, epiluminescence microscopy, incident light microscopy, skin microscopy), has been shown to provide additional features and subtle clues for the assessment of pigmented skin lesions. METHODS: The pigmented lesions are covered in vivo with a drop of immersion oil and a glass slide, and observed in incident light by using a stereomicroscope (magnification 6- to 40-fold) or a hand-held instrument called dermatoscope (magnification 10-fold). The immersion oil renders the stratum corneum translucent and allows a better observation of distinctive alterations of the dermoepidermal junction and the papillary dermis. RESULTS: The various criteria of surface microscopy (e.g. pigment network, black dots or irregular extensions) that cannot be discerned by the naked eye are summarized and discussed in detail. The diagnostic significance but also the limitations of this technique are emphasized. CONCLUSION: Surface microscopy opens up a new dimension of clinical morphology for the diagnosis of pigmented skin tumors and facilitates a more reliable assessment of the lesions.

Angiokeratoma↗
PubMed1993

[Electron microscopy of needle biopsies from cancer patients with unknown primary tumors].

The aim of the present study was to evaluate the diagnostic value of electron microscopy (EM) performed on Surecut biopsies from patients without known primary tumour. The material consisted of 108 consecutive biopsies, obtained over a period of two years, from patients with tumour(s) in the liver or lymph nodes (on the neck, in the axilla or retroperitoneum). From each patient fine needle aspirations and Surecut biopsies for light microscopy and electron microscopy were taken. Only biopsies in which material for both electron microscopy and light microscopy was sufficient were included (60%). Immunohistochemical reactions were performed on paraffin sections when indicated. Final diagnoses were confirmed on surgically removed specimens and/or autopsies. Electron microscopy was necessary for obtaining the final histological diagnosis in 15% of the cases. It is therefore recommended to obtain additional ultrasound guided biopsies for EM from cancer patients with tumours in the liver or lymph nodes in cases where the primary origin of the tumour is unknown.

Biopsy, Needle↗
PubMed2001

Electron and video-light microscopy analysis of the in vitro effects of pyrantel pamoate on Giardia lamblia.

Electron and video-light microscopy analysis of the in vitro effects of pyrantel pamoate on Giardia lamblia. Experimental Parasitology 97, 9-14. Giardia infection is predominant in the small intestine of vertebrates, where the trophozoites attach to epithelial cells and adversely affect the microvilli and other epithelial cell structures. Giardiasis, the disease caused by this protozoan, is very common in developing countries and mainly affects children. Drugs currently used to treat Giardia infection, such as some benzimidazole derivatives, were originally designed to treat helminthic infections. Many of the drugs are known to cause severe side effects and disturbances to the patient. Using transmission electron microscopy and video-light microscopy, we studied the effects of pyrantel pamoate, a drug commonly used in the treatment of helminthic infections in horses and ruminants, on Giardia lamblia trophozoites. Pyrantel pamoate was administered to Giardia cells in four different concentrations. Using video-light microscopy, we observed the decrease in flagella beating frequency and severe changes in the lateral flange and in the general aspect of the cell. Using transmission electron microscopy, we observed changes in the cytoplasm and peripheral vesicles. The flagella and adhesive disk structure were not affected. Apparently, the effects of pyrantel pamoate are irreversible.

Animals↗
PubMed1976

Morphology, morphometry and electron microscopy of HeLa cells infected with bovine Mycoplasma.

The host-parasite relationship of HeLa M cells artificially infected with a bovine species of Mycoplasma was studied by light microscopy, transmission electron microscopy and scanning electron microscopy. The use of morphometry to quantitate some of the findings was explored. The parasites were seen in locations extracellular to the cell surface. The detection of small numbers of organisms by light microscopy was well demonstrated by use of the flurescent antibody technique. Scanning electron microscopy proved to be an excellent method for revealing the surface details of cell-parasite morphology. Ultra-thin sections showed that the parasites are aligned mostly parallel to the plasma membrane of the host cell but separated by a gap of 10nm. Morphometry indicated an average of 69 organisms per cell surface occupying 1.7% of the surface area. An increase of 26% in diameter of the HeLa cells, possibly as a result of infection, was observed.

Biometry↗
PubMed2004

Microscopy and the helminth parasite.

Microscopy has a long and distinguished history in the study of helminth parasites and has made a singularly outstanding contribution to understanding how these complex animals organise their lives and relate to their hosts. Increasingly, the microscope has been used as a powerful investigative tool in multidisciplinary approaches to parasitological problems, placing emphasis on functional correlates rather than anatomical detail. In doing so, microscopy has also uncovered a number of attributes of parasites that are of wider significance in the field of biology. Parasite surfaces have understandably demanded most of the attention of microscopists, largely as a result of the pioneering studies using transmission electron microscopy. Their findings focused the attention of physiologists and immunologists on the tegument and cuticle of helminths and in doing so helped unravel the complex molecular exchanges that are fundamental to understanding host-parasite interactions. Scanning electron microscopy succeeded in augmenting these data by revealing novel microtopographical features of the host-parasite relationship, as well as proving invaluable in helminth taxonomy and in assessing the efficacy of test substances in drug screens. Control of helminth parasites has never been more critical: problems of drug resistance demand urgent action to identify exploitable targets for new generation anthelmintics. In this regard, the neuropeptide signalling system of helminths is envisioned as central to nerve-muscle function, and thereby a crucial regulatory influence on their motility, alimentation and reproduction. The use of immunocytochemistry interfaced with confocal scanning laser microscopy has not only been instrumental in discovering the peptidergic system of helminths and its potential for chemotherapeutic exploitation, but through increasingly sophisticated bio-imaging technologies has continued to help dissect and analyse the molecular dynamics of this and other cellular systems within these important parasites.

Animals↗
PubMed1999

Direct ultrastructural imaging of macrophages using a novel x-ray contact microscopy.

A compact, high-resolution, laser-plasma, x-ray contact microscopy method using a table-top Nd:glass laser system has been developed. This x-ray microscopy system was applied for the observation of macrophage ultrastructures. These images were produced using proximity imaging in which a 5-ns pulse of soft x-rays with wavelengths near and inside the water windows (23A-44A) produced by the laser-plasma were absorbed by the specimen and then registered on a photo resist. The x-ray images imprinted on the photo resist were then developed and analyzed with an atomic force microscope (AFM). Mouse thioglycollate-elicited peritoneal macrophages in suspension were examined by this new x-ray microscope. The x-ray images of the macrophages were compared with those observed by conventional transmission electron microscopy (TEM). The x-ray images showed no obvious organelles, including the nucleus and endoplasmic reticulum, as can be seen with TEM, but high- and low-contrast structures caused by mass distribution of carbon were observed. Thus, using the x-ray microscopy we visualized the first x-ray images of macrophage ultrastructures. The successful x-ray imaging of macrophage ultrastructure indicates that proximity x-ray microscopy may be of value in studying physiology linked to the dynamics of a cell.

Animals↗
PubMed2003

Correlative microscopy of ultrathin cryosections is a powerful tool for placental research.

In this report, we describe procedures for correlative fluorescence and electron microscopy in immunocytochemical studies on the human placenta. Ultrathin cryosections of placenta were used for detection of the distribution of antigens by immunofluorescence and subsequently by immunoelectron microscopy of the same ultrathin cryosection. This methodology has certain advantages over conventional immunohistochemistry and immunoelectron microscopy. The advantages are, most notably, that the same exact structures are examined by both imaging modalities. In addition, since the tissue is physically sectioned (50-100 nm thickness), greater resolution for fluorescence can be obtained in the z-dimension than can be obtained by optical sectioning in confocal microscopy. This last point is of particular importance for discriminating between structures closely stacked in the z-dimension. In this report, we have determined the distribution of caveolin-1 in ultrathin cryosections of terminal villi of the human term placenta. We demonstrate that the use of ultrathin cryosections is a powerful approach for immunofluorescence and correlative microscopy for the in situ localization of antigens.

Adult↗
PubMed2006

Breaking the resolution limit in light microscopy.

Fluorescent imaging microscopy has been an essential tool for biologists over many years, especially after the discovery of the green fluorescent protein and the possibility of tagging virtually every protein with it. In recent years dramatic enhancement of the level of detail at which a fluorescing structure of interest can be imaged have been achieved. We review classical and new developments in high-resolution microscopy, and describe how these methods have been used in biological research. Classical methods include widefield and confocal microscopy whereas novel approaches range from linear methods such as 4Pi, I(5) and structured illumination microscopy to non-linear schemes such as stimulated emission depletion and saturated structured illumination. Localization based approaches (e.g. PALM and STORM), near-field methods and total internal refraction microscopy are also discussed. As the terms 'resolution', 'sensitivity', 'sampling' and 'precision' are sometimes confused, we explain their clear distinction. Key concepts such as the point spread function and the Abbe limit, which are necessary for an in depth understanding of the presented methods, are described without requiring extensive mathematical training.

Animals↗
PubMed2005

Fast functional imaging of single neurons using random-access multiphoton (RAMP) microscopy.

The successful study of dendritic signaling and computation requires the ability to simultaneously monitor neuronal activity at multiple cellular sites. While the difficulties of accessing dendritic submicron structures with conventional micropipette approaches are generally overcome by optical recording techniques, their spatio-temporal resolution has limited such studies to few sites or slow signals. Here we present a novel approach to functional imaging, termed random-access multiphoton (RAMP) microscopy, which combines multiphoton excitation with an inertia-free scanning mechanism. RAMP microscopy employs two-dimensional acousto-optic deflection to rapidly position a focused near-infrared ultrafast laser beam between dwell periods at multiple user-selected sites. Because neuronal structures are generally sparse, activity located throughout various compartments, including thin dendritic branches and spines, can be mapped at high frame rates while maintaining the signal-to-noise ratio of conventional scanning microscopy. Moreover, RAMP microscopy maintains the excellent structural imaging capability of multiphoton excitation, i.e., intrinsic optical sectioning and high lateral resolution from within highly light-scattering brain tissue. RAMP microscopy thus comprises a versatile tool for investigating correlations of dendritic structure and function with significantly enhanced experimental throughput.

Action Potentials↗
PubMed1996

A total sample preparation method for the measurement of airborne asbestos and other fibers by optical and electron microscopy.

A total sample preparation method utilizing one membrane filter for all or some of the measurements by phase contrast optical microscopy (PCM), optical microscopy (OM), dispersion staining polarized microscopy (DS/PLM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), was developed in order to evaluate airborne asbestos and other mineral fibers comprehensively, including fiber number, sizes and types, in various environments. This method consists of two alternate procedures: parallel and serial preparation. The former uses different portions of a filter for each measurement of PCM, OM, DS/PLM, SEM and TEM. The latter uses a single filter portion for all OM, SEM and TEM measurements by which the same area and same fibers on the filter can be observed. This allows fiber numbers to be directly compared using these measurements on the same filter area, and the fibers observed by OM can be also examined by SEM and/or TEM equipped with an energy dispersive X-ray spectrometer (EDX) to determine the types and precise sizes. Using this method, it was found that OM measurements developed in this study can visualize thinner fibers than PCM measurements and make it easier to count fibers. We also found that currently used PCM measurement can detect fibers thicker than about 0.4-0.5 microns in diameter. This total sample preparation method can be used not only for air samples, but also for liquid and biological tissue samples.

Air Pollutants, Occupational↗
PubMed1998

Analytical Microscopy in the Real Semiconductor Processing World.

: In the microelectronic semiconductor world we are bombarded with reports of how the drive toward faster, denser, lower power-consuming and more reliable semiconductor products will accelerate with time. This paper discusses the instrumental evolution from visible light microscopy to scanning electron microscopy and on to transmission electron microscopy and scanned probe microscopy. The increased demands placed on specimen preparation of precise locations in a semiconductor chip for microscopy are discussed. Analytical microscopy has to be timely in order to be a viable adjunct to semiconductor manufacturing. The factors governing analysis of turn-around time are explained and an optimum strategy is suggested for effective utilization of finite laboratory resources. The new instrumentation available to the microscopist is introduced along with an overview of the exciting new analyses that will be available in the immediate future.

Journal Article↗
PubMed2000

Development of an X-ray photoemission electron microscopy system with multi-probes, and its application to surface imaging at static and dynamic states.

We have developed a new X-ray photoemission electron microscopy system combined with low energy electron microscopy, photoemission electron microscopy, mirror electron microscopy (MEM), secondary electron emission microscopy (SEEM) and Auger electron emission microscopy, which provides multi-angle information on the distribution and change of element, chemical state, structure, etc. at solid surfaces under the working conditions such as high temperature and gas atmosphere. The performance of each microscopical method was examined and typical images are presented. The dynamic behaviour of fabricated surfaces has been imaged in real time by SEEM and MEM.

Journal Article↗
PubMed2001

Applications of microscopy to the deformation and fracture of rubber-toughened polymers.

The principal mechanisms of inelastic deformation in rubber-toughened plastics, and in other similar multiphase polymers, are shear yielding and multiple crazing in the rigid matrix phase, and cavitation in the soft disperse phase. Microscopy has played a very important part in the identification and study of these mechanisms. However, no one technique has been predominant. Polarized-light microscopy is useful for observing crazing, and has proved to be the most effective method for studying shear yielding, whereas transmission electron microscopy has provided valuable insights into the cavitation behaviour of complex rubber particles. Scanning electron microscopy has made significant contributions in the study of all three micromechanisms. In some microscopy investigations, thin sections have been strained in situ on the microscope stage. In others, specimens have been deformed in the bulk state before being polished and etched, or stained and microtomed, or coated with a thin layer of metal, in preparation for examination in the microscope. The importance of combining microscopy with other, complementary methods for studying deformation micromechanics is emphasized, and two novel methods for detecting cavitation in multiphase polymers are discussed briefly.

Journal Article↗
PubMed2004

Comparison of corneal thickness measurements using Orbscan II, non-contact specular microscopy, and ultrasonic pachymetry in eyes after laser in situ keratomileusis.

AIMS: To compare central corneal thickness measurements of three pachymetry devices in eyes after laser in situ keratomileusis (LASIK). METHODS: Central corneal thickness was measured in 203 eyes after myopic LASIK. Orbscan II scanning slit topography (Bausch & Lomb), SP-2000P non-contact specular microscopy (Topcon), and ultrasonic pachymetry (Tomey) were used in this sequence. RESULTS: Three devices gave significantly different corneal thickness readings (p<0.0001, repeated measure analysis of variance). The measurements of Orbscan II (445.6 (SD 60.0) microm) were significantly smaller than those of noncontact specular microscopy (467.9 (SD 40.2) micro m; p<0.0001, Tukey multiple comparison) and ultrasonic pachymetry (478.8 (SD 41.9) microm; p<0.0001). The value obtained with SP-2000P non-contact specular microscopy was significantly smaller than that taken with ultrasonic pachymetry (p<0.001). There were significant linear correlations between scanning slit topography and non-contact specular microscopy (Pearson's correlation coefficient r = 0.912, p<0.0001), non-contact specular microscopy and ultrasonic pachymetry (r = 0.968, p<0.0001), and ultrasonic pachymetry and scanning slit topography (r = 0.933, p<0.0001). CONCLUSION: In post-LASIK eyes, Orbscan II scanning slit topography significantly underestimated corneal thickness. Non-contact specular microscopy gave smaller thickness readings than ultrasonic pachymetry, but these two units showed an excellent linear correlation.

Adult↗