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PubMed1983

Evaluation of glomerular and nonglomerular hematuria by phase-contrast microscopy.

Glomerular and nonglomerular origins of hematuria may be identified by assessment of the shape and size of the excreted red blood cells. We examined 380 urine specimens from 179 children with hematuria (greater than or equal to 3500 RBC/minute) with phase-contrast microscopy. In 106 cases, the cause was known; the results agreed with the clinical, histologic, and laboratory diagnosis in 63 of 65 subjects (97%) with glomerulopathies and in 39 of 41 (95%) with nonglomerular hematuria. Casts were found in 54% of the specimens from the children with definite glomerular hematuria. Phase-contrast microscopic examination of red blood cells in the urine is a simple, inexpensive, and noninvasive technique that permits an accurate distinction between glomerular and nonglomerular bleeding in pediatric patients.

Adolescent↗
PubMed1993

[Clinical value of studying hematuria using phase-contrast microscopy].

To evaluate the examination of urine erythrocytes with a contrast phase microscope for the etiological diagnosis of haematuria (erythrocytes > 10/mm3 of non centrifuged urine) the charts of 84 patients with haematuria were reviewed. A nephrological origin had been established with certainty in 56 cases with a renal biopsy and an urological origin was also established with certainty in 28 cases thanks to appropriate radiological, endoscopical and pathological examinations. The morphological criteria of the erythrocytes deformation were those of Birch and Fairley but the quantitative criteria of these authors (either 80 or 100%) were found to be of no value. By successive approaches the threshold of 20% of deformed erythrocytes was selected and found to be the best criterion for diagnosing glomerular hematuria: the sensitivity of the test is then 73% and its specificity 60%. As these results were relatively modest, conditions which decrease the percentage of deformed erythrocytes were excluded to improve the sensitivity, such as macroscopic haematuria and also examinations made during the 6 hours following furosemide administration whereas conditions which increase the percentage of deformed erythrocytes and which are easily diagnosed such as urinary infections, lithiasis and renal insufficiency associated with an uropathy were excluded in order to improve the specificity. Then the examination has a sensitivity and a specificity of 90% which makes it clinically relevant, authorizing a wait and see attitude in case there is an isolated microscopic haematuria of glomerular type.

Diagnosis, Differential↗
PubMed1987

Phase-contrast microscopy of the primate retina.

The study of hematoxylin and eosin stained thick sections (15 microns) of the primate retina with the phase-contrast microscope provided a means for the selective demonstration of many cellular structures that could not be resolved with the same degree of detail which was possible when bright-field microscopy was used, or when phase-contrast microscopy was employed to examine unstained material. The H & E-stain greatly enhanced the phase-contrast image, so that cytoplasmic structure, fiber trajectories, and gross synaptic detail of the retina could be demonstrated to better advantage.

Animals↗
PubMed2006

Quantitative phase-contrast microscopy by a lateral shear approach to digital holographic image reconstruction.

Combining the concept of lateral shear interferometry (LSI) within a digital holography microscope, we demonstrate that it is possible to obtain quantitative optical phase measurement in microscopy by a new single-image-processing procedure. Numerical lateral shear of the reconstructed wavefront in the image plane makes it possible to retrieve the derivative of the wavefront and remove the defocus aberration term introduced by the microscope objective. The method is tested to investigate a silicon structure and a mouse cell line.

Algorithms↗
PubMed1985

Accuracy of low platelet counts on the Coulter S-Plus IV.

Recent improvements have occurred in the flagging criteria for erroneous platelet counts on Coulter S-Plus series instruments. The authors tested the accuracy of the S-Plus IV on over 400 patient samples with low platelet counts (less than 50,000/microL) as compared with phase microscopy. Only a small number of samples gave discrepant results (difference greater than 10,000/microL), and, when investigated, most often were found to be due to erratic phase microscopy results. Approximately one-third of all low platelet counts in our laboratory were flagged ("error code 10") by the instrument and required determination by phase microscopy. In addition, to prevent erroneous results due to giant platelets or microcytic red blood cells, the platelet histogram should be inspected for return to baseline at 20 cubic micrometers (fL).

Evaluation Studies as Topic↗
PubMed2006

Combined phase-sensitive acoustic microscopy and confocal laser scanning microscopy.

Combined phase-sensitive acoustic microscopy (PSAM) at 1.2 GHz and confocal laser scanning microscopy (CLSM) in reflection and fluorescence has been implemented and applied to polymer blend films and fluorescently labeled fibroblasts and neuronal cells in order to explore the prospects and the various contrast mechanisms of this powerful technique. Topographic contrast is available for appropriate samples from CLSM in reflection and, with significantly higher precision, from the acoustic phase images. Material contrast can be gained from acoustic amplitude V(z) graphs. In the case of the biological cells investigated, the optical and acoustic images are very different and exhibit different features of the samples.

3T3 Cells↗
PubMed1985

Effects of the synthetic glucocorticoid betamethasone on the survival of neurons in fetal rabbit brain cell culture.

Dissociated fetal rabbit brain cells were grown on petri dishes coated with collagen. Culture medium consisted of Dulbecco's Modified Eagles Medium plus 10% serum. The mitotic inhibitor 1-beta-D-arabinofuranosylcytosine was added at 6 days for a 2 day period to inhibit over-growth by glial cells and fibroblasts. In some cases cultures were chronically exposed to 0.5, 1.0 or 2.0 microM betamethasone. Examination of cultures by phase microscopy and acetylcholinesterase (AChE) staining demonstrated that cultures incubated with 1.0 and 2.0 microM betamethasone contained 2-2.5 times as many neurons as compared to control cultures. Furthermore, there was an increase in the specific activities of both AChE and choline acetyltransferase (ChAT) which were proportional to the increase in neuronal cell numbers obtained from phase microscopy and AChE staining. These results suggested that betamethasone enhanced survival of cholinergic neurons. Cultures were also examined for neuron specific gamma-aminobutyric acid (GABA) uptake. Again GABA uptake was approximately 2-2.5 times as great in cultures incubated with 1-2 microM betamethasone when compared to controls. Thus, the increase in GABA uptake paralleled the increase in neurons observed by phase microscopy and AChE staining, suggesting that the survival effect of betamethasone was not specific to cholinergic neurons. While betamethasone treated cultures always contained greater numbers of neurons the percentage of neurons lost from all cultures after 2 weeks was the same.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholinesterase↗
PubMed1998

A comparison of historic asbestos measurements using a thermal precipitator with the membrane filter-phase contrast microscopy method.

The published results and analytical methods used in a 1938 survey of the spinning area in a UK crocidolite asbestos factory have been described and re-interpreted, by comparing the method used with the current membrane filter-phase contrast microscopy (MF-PCM) method for asbestos. By good fortune, most of the original microscope, and thermal precipitator sampling heads similar to those used for sampling were available, as well as guidance from the factory inspector who collected and analysed the original samples. A textile grade crocidolite asbestos was used to generate a fibrous dust cloud whose size distribution was characterised by scanning and transmission electron microscopy and found to give a close approximation to the fibre size distributions monitored in 1938. Samples taken over the same sampling time, but at lower concentrations than originally sampled, showed that the thermal precipitator-oil immersion microscopy (TP-OI) method used at x 2000 magnification, gave higher > 5 microns long fibre counts by a factor of between 3 and 4, than the current MF-PCM method. The differences in performance could be explained by the superior resolving power of the TP-OI method for fine crocidolite fibres. Exposures of airborne asbestos fibres in the spinning area were found to be equivalent to about 20 f ml-1 for personal samples and 10 f ml-1 for area samples, but due to the high levels of ventilation on the day the samples were collected, the average levels throughout the year may have been somewhat higher.

Air Pollutants, Occupational↗
PubMed2006

Four-dimensional ultrafast electron microscopy of phase transitions.

Reported here is direct imaging (and diffraction) by using 4D ultrafast electron microscopy (UEM) with combined spatial and temporal resolutions. In the first phase of UEM, it was possible to obtain snapshot images by using timed, single-electron packets; each packet is free of space-charge effects. Here, we demonstrate the ability to obtain sequences of snapshots ("movies") with atomic-scale spatial resolution and ultrashort temporal resolution. Specifically, it is shown that ultrafast metal-insulator phase transitions can be studied with these achieved spatial and temporal resolutions. The diffraction (atomic scale) and images (nanometer scale) we obtained manifest the structural phase transition with its characteristic hysteresis, and the time scale involved (100 fs) is now studied by directly monitoring coordinates of the atoms themselves.

Crystallization↗
PubMed1999

Detection of movement at the erythrocyte's edge by scanning phase contrast microscopy.

A time-dependent set of line scans across an erythrocyte was recorded by a phase contrast laser scanning microscope. A method for edge detection, based on a two-stage fitting procedure of the theoretical intensity distribution in a line scan of phase contrast image to the experimental one, is suggested. Time-resolved fluctuations of the human erythrocyte's edge were obtained, employing this method. The same procedure was carried out for a metallic strip yielding a test for the background noise level. The suggested method was applied in examining the effect of chemical crosslinking and thiol reduction on cell membrane fluctuations of human erythrocytes.

Cell Movement↗
PubMed1982

[On the growth of cultured bovine aortic endothelial cells. Preliminary observations on ultrastructural morphology by freeze-etching and quantitation of growth rate by phase contrast microscopy: effect of glycosaminoglycans].

Bovine aortic endothelial cells (BAEC), detached from thoracic aorta by collagenase treatment, have been studied after adding a mixture of glycosaminoglycans (GAGs) (the composition of which has been studied by Casu et al. -6), at different concentrations. GAGs at the concentration of 90 mg/100 ml of medium (Dulbecco's modification of Eagle's MEM with 10% foetal calf serum) produced an increase in the growth speed. We have quantitized these data both by counting the number of cells 24 h after trypsinization in phase-contrast-microscopy, and by measuring the time necessary to reach a certain number of influences. Ultrastructural observation at transmission electron microscope after freeze-etching preparation, didn't show any relevant modification either in the organization of cell membrane or in the cytoplasmatic structures. In some observations a conspicuous increase of "vesicular openings" ("pits") on the plasmatic membrane was evident. Statistical evaluation of this phenomenon is under consideration.

Animals↗
PubMed1976

[A study of the polyploid nuclei of the giant trophoblast cells of several species of rodents using phase contrast microscopy].

Patterns of chromosome morphology in high polyploid trophoblast nuclei of placenta were compared in the rat, rabbit and Microtus arvalis. In the rat and rabbit placenta two types of nuclei were recognized. Some nuclei have ribbon-like chromosomes, while others display thin oligotene fibrils with paired chromomers evenly distributed throughout all karyoplasm. In the latter case, the polytenic structure of chromosomes is seen preserved only near the nucleoli. In the rat and rabbit trophoblast nuclei, the ribbon-like polytene chromosomes could be distinguished only with phase contrast microscopy. In the trophoblast nuclei of Microtus arvalis polytene chromosomes were found only at early stages of embryonic development (9 day old embryo). On later stages of cell differentiation, the chromosomes or chromosome rosetts are seen. Similarities in mechanisms of polyploidization in the high polyploid nuclei of Diptera and in trophoblast nuclei of rodents are discussed.

Animals↗
PubMed2004

Recording of single-particle hysteresis loops with differential phase contrast microscopy.

The magnetic behaviour of laterally patterned structures on a micrometer or nanometer scale in external magnetic fields can be described by their hysteresis loops. However, it is very difficult to record the hysteresis loop of a single (sub-) micron-sized particle. Furthermore, extensive calculations are necessary in order to interpret the shape of the loop and to conclude the micromagnetic domain configuration in the sample from the hysteresis loop only. We have developed a technique which yields both the hysteresis loop and the magnetic domain structure simultaneously. This method uses differential phase contrast microscopy and a microscope with remote control capability for the automatic recording of a single-particle hysteresis loop.

Journal Article↗
PubMedDate not supplied

Comparison of fiber counting by TV screen and eyepieces of phase contrast microscopy.

This study designed a modified light path of a phase-contrast microscope to evaluate the feasibility of fiber counting on a television screen (TVS). A comparison also was made of the fiber counts, fiber density, and precision derived from repeatedly counting fibers through eyepieces (EPs) and on a TVS connected to a phase contrast microscope. Thirty asbestos fiber samples were counted 10 times repeatedly. Ten samples were counted by viewing the same field through an EP and on a TVS alternately, whereas the other 20 samples were counted separately by using an EP and a TVS. The A rules of National Institute for Occupational Safety and Health (NIOSH) 7400 method was quoted. No statistically significant difference of fiber density (p = 0.39) or fiber counts (p > 0.05) was observed between the TVS and EP methods, though TVS gave a slightly lower value than EP did. The bias of the two methods was 7.7 +/- 8.0% on an average. The relative standard deviations (RSDs) for both methods were the same, 0.40, which resembled the theoretical RSD, 0.44, of NIOSH 7400. Meanwhile, the theoretical and experimental RSDs were not significantly different for either method (p > 0.05). The modified light path of a phase contrast microscope provided a compatible view with less eye strain on a TVS than a conventional EP. Moreover, operator biases and variability might be greatly reduced by training several counters simultaneously on the TVS.

Asbestos↗
PubMed2003

Morphology, homogeneity and functionality of human monocytes-derived macrophages.

Primary cultures of human monocyte-derived macrophages (n = 50) were characterized in order to use this cellular model to establish a proteomic map of macrophages. Peripheral blood mononuclear cells were isolated from healthy donors' blood using density gradient centrifugation. The cell culture quality was checked in respect of several morphological and molecular aspects. The homogeneity and purity of cells was assessed after 12 days' primary culture with phase microscopy, immunocytochemistry and flow cytometry. Monocytes were completely differentiated into macrophages within 12 days as shown by phase microscopy. On day 12, all cells expressed CD68 antigen and were negative for CD3. Flow cytometry experiments showed a purity of the primary culture on day 12, in a range between 76% and 98% of CD14+ cells. The functionality of cells was characterized for the presence of ECE-1 as an intracellular marker and for the presence of MMP-9 as a marker secreted into the culture medium. This study allowed to determine criteria of quality and functionality for the primary culture of monocyte-derived macrophages. Cultures meeting these criteria will be used for the proteomic analysis and the establishment of the reference map.

Biomarkers↗
PubMed2004

Comparison of nanoparticle size and electrophoretic mobility measurements using a carbon-nanotube-based coulter counter, dynamic light scattering, transmission electron microscopy, and phase analysis light scattering.

The precision and accuracy of measurements of the diameter and electrophoretic mobility (mu) of polymeric nanoparticles is compared using four different analytical approaches: carbon-nanotube-based Coulter counting, dynamic light scattering (DLS), transmission electron microscopy (TEM), and phase analysis light scattering (PALS). Carbon-nanotube-based Coulter counters (CNCCs) use a 132 nm diameter channel to simultaneously determine the diameter (28-90 nm) and mu value for individual nanoparticles. These measurements are made without calibration of the CNCC and without labeling the sample. Moreover, because CNCCs measure the properties of individual particles, they provide true averages and polydispersities that are not convoluted into the intrinsic instrumental response function of the CNCC. CNCCs can be used to measure the size of individual nanoparticles dispersed in aqueous solutions, which contrasts with the TEM-measured size of individual dehydrated particles and the ensemble size averages of dispersed particles provided by DLS. CNCCs provide more precise values of mu than PALS.

Journal Article↗
PubMed2002

Quantitative X-ray projection microscopy: phase-contrast and multi-spectral imaging.

We outline a new approach to X-ray projection microscopy in a scanning electron microscope (SEM), which exploits phase contrast to boost the quality and information content of images. These developments have been made possible by the combination of a high-brightness field-emission gun (FEG)-based SEM, direct detection CCD technology and new phase retrieval algorithms. Using this approach we have been able to obtain spatial resolution of < 0.2 micro m and have demonstrated novel features such as: (i) phase-contrast enhanced visibility of high spatial frequency image features (e.g. edges and boundaries) over a wide energy range; (ii) energy-resolved imaging to simultaneously produce multiple quasi-monochromatic images using broad-band polychromatic illumination; (iii) easy implementation of microtomography; (iv) rapid and robust phase/amplitude-retrieval algorithms to enable new real-time and quantitative modes of microscopic imaging. These algorithms can also be applied successfully to recover object-plane information from intermediate-field images, unlocking the potentially greater contrast and resolution of the intermediate-field regime. Widespread applications are envisaged for fields such as materials science, biological and biomedical research and microelectronics device inspection. Some illustrative examples are presented. The quantitative methods described here are also very relevant to projection microscopy using other sources of radiation, such as visible light and electrons.

Journal Article↗