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Results for “MICROSCOPY, PHASE CONTRAST”

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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↗
PubMed1989

[Vital staining and phase contrast microscopy results of plaque smears].

The information about the vitality of the plaque is limited. Only motile bacteria can be distinguished as alive. Vital staining allows to differentiate between living nonmotile rods and dead, previously motile rods. With increasing severity of the periodontal destruction, the proportion of alive respectively motile rods and vibrions increases. The vital staining shows very clearly the relation between destruction and living rods.

Adolescent↗
PubMed1999

[The role of phase contrast microscopy in the evaluation of cervix neck and vaginal biocenosis].

The aim of our study was to evaluate and compare the possibility of germ identification in cervico-vaginal infections of different origin by Ph cytology and classic fixated and stained (H-E) smears. We identified Lactobacillus vag., Gardnerella vag., short bacilli (Escherichia coli, Proteus, Klebsiella), mixed Coccus flora (diplococci, small and large cocci), Trichomonas vag., and Candidia alb. in cervico-vaginal smears. In endocervical, mature metaplastic or parabasal cells the elementary and cocoid bodies of Chlamydia trachomatis were possible to observed. The cytopathic effects caused by viral infections (HPV, HSV, CMV) were detected. The classic (koilocytosis, dyskeratosis) and discrete (binucleation, cracked cells, ghost cells, tadpole cells and large cytoplasmatic hyaline granulations) morphological changes must be confirmed by colposcopy and Digene Hybryde Capture analysis. The results of identification of vaginal biocenosis in Ph microscope and H-E smears were similar. The main benefit of Ph cytology is accuracy, speed and reliability of comprehensive information.

Adolescent↗
PubMed1999

[Integrated colposcopy and phase contrast microscopy for diagnosis of squamous intraepithelial lesions and invasive cervical neoplasms].

Colposcopy or cytology examinations alone allows to obtain diagnostic concordance with histopathological examination between 74-89% and 68-86%, respectively in SIL and cervical cancer detection. Both methods used simultaneously allow increase concordance with histopathology up to 95-100%. Cytological examination may be used simultaneously with colposcopy when Ph microscopy is used. The aim was to estimate benefits of conjunction of colposcopy and Ph cytology in SIL and cervical cancer detection in daily gynecological practice. Integrated colposcopy and cytology examinations were performed in 200 patients. Cervico-vaginal smears were obtained from the patient before Acetic-Acid Test and Lugol-Solution-Test were performed. Wet smears (Ph) were made. Results of integrated colposcopy and cytology were verified by histopathological examination. Diagnostic specificity, sensitivity, and Youden's value were estimated for Ph cytology, H-E cytology, and colposcopy alone and for integrated colposcopy and Ph cytology. Simultaneous colposcopy and Ph cytology reveal specificity 97.1% sensitivity 94.6% and Youden's value 91.8% thus provide fast, reliable and comprehensive information for accurate diagnosis in daily gynecological practice.

Carcinoma, Squamous Cell↗
PubMed1987

Use of phase contrast microscopy to determine the height of the organ of Corti in whole-mount preparations.

A technique has been developed to measure the height of the organ of Corti (OC) in the whole-mount preparations of the cochlear duct. The technique corrects for variations in the microscope system, such as the magnification of the objective lens and the mechanical properties of the fine-focus knob, as well as the refractive index of the embedding medium and the angle of specimens with respect to the optical axis of the microscope. At 11 percentage locations from apex to base, the height of the OC in ten chinchilla cochleas was measured at three positions: (1) the lateral edge of the inner hair cell (IHC); (2) the medial edge of the first row outer hair cell (OHC1); and (3) the lateral edge of the third row outer hair cell (OHC3). These measurements were compared to measurements made on radial sections from five other cochleas, with very good agreement at IHC and OHC3, and fairly good agreement at OHC1. The height at OHC3 varied almost linearly with percentage distance along the OC, ranging from 96 microns (apical end) to 51 microns (basal end). The height at the OHC1 varied from 77 to 49 microns, but did not vary linearly. The height of the IHC was relatively constant, from 50 to 60 microns, except at the basal end, where it decreased to 42 microns.

Animals↗
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↗
PubMed1987

Evaluation of the phase contrast microscopy method for the detection of fibrous and other elongated mineral particulates by comparison with a STEM technique.

The USPHS/NIOSH Membrane Filter Method is used to monitor for asbestos in occupational and mining atmospheres, and employs the phase-contrast optical microscope (PCM) that under optimum conditions has a resolution of approximately 0.25 micron. While amphibole cleavage fragments are usually visible by PCM, asbestos fibers (such as amosite and chrysotile) have finer widths that may render them invisible by PCM. In this study, personal air-monitoring filters containing chrysotile, amosite and amphibole cleavage fragments from various sources have been analyzed by PCM in accordance with the USPHS/NIOSH Method and scanning transmission electron microscopy (STEM) to assess the effectiveness of the PCM technique. Each STEM specimen was prepared using a direct-transfer technique to ensure that particle size distribution and concentration were not altered. STEM results for chrysotile samples are highly variable, with 9% to 81% of regulatory particles having widths smaller than 0.25 micron--the resolution of the optical microscope. Amosite samples have 27% to 38% of regulatory particles with widths below microscope resolution, indicating that routine particle counts by PCM on these samples would underestimate true fiber content by approximately one-third. All amphibole cleavage fragment samples had regulatory particles that would be observed by PCM. Multiplication factors have been suggested for application to routine counts by PCM to more accurately assess true particle content for mineral particulates on personal air-monitoring filters.

Air Pollutants, Occupational↗
PubMed1980

Morphological study of the bovine blastocyst with phase contrast microscopy.

The morpholoqical appearance of 40 bovine blastocysts. collected from single ovulating heifers 7 days after oestrus was evaluated with the aid of a phase contrast inverted microscope. Out of 40 blastocysts, 17 were classified normal (N), 14 in the process of degeneration (IPD) and 9 degenerated (D). There was no difference in the mean diameters of the three groups of blastocysts, whereas the mean diameters of cell mass was bigger in N than IPD and D blastocysts. This difference was highly significant (P<.005). The mean number of cells was greater in normal than in abnormal (99 vs 58). This difference was highly significant (P<.005). The results reported here indicate that the criteria used for classification of the morphological appearance of the 7 day old bovine blastocyst reflected the degree of cellular organization and the number of cells.

Journal Article↗