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Results for “MICROSCOPY, PHASE CONTRAST”

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At least 19 recordsLinked to original sources
PubMed1986

[Morphologic study of microscopic hematuria using phase contrast microscopy].

Phase contrast microscopic examination of the urine has been recently reported to be valuable in predicting whether hematuria is due to glomerulonephritis or not. Phase contrast microscopy can differentiate glomerular red cells from nonglomerular ones since the former varies in size and shape with distortion, whereas the latter is uniform in size and shape. Urinalysis of 217 cases of microscopic hematuria was performed at our Hospital. Red blood cells were classified into two types, glomerular and nonglomerular type. Ninety percent of the cases of bladder leukoplakia as well as all cases of glomerulonephritis had glomerular type red blood cells.

Diagnosis, Differential↗
PubMed1985

Diagnostic value of phase contrast microscopy in haematuria.

Phase contrast microscopic examination of 105 urine specimens was carried out in a study to differentiate glomerular from nonglomerular haematuria. Urine was obtained from patients with proven glomerular disease, healthy subjects, and healthy subjects to whose urine blood had been added. Phase contrast microscopy identified correctly glomerular haematuria in 74 out of 80 samples, and nonglomerular erythrocyturia in all the 25 samples tested. These results give a sensitivity rate of 93% and specificity of 100%. Phase contrast microscopy was found to be a useful screening test in the investigation of haematuria.

False Negative Reactions↗
PubMed1997

Evaluation of particulate embolic materials with MR imaging, scanning electron microscopy, and phase-contrast microscopy.

PURPOSE: To analyze the properties and embolic effect of microfibrillar collagen (MFC), Gelfoam powder, and polyvinyl alcohol (PVA) materials that are used in embolization procedures in the head and neck. METHODS: The shape and surface of these embolic agents were examined with scanning electron microscopy and phase-contrast microscopy. The mean number of areas of T2-weighted high signal intensity was measured on MR images in a rat embolization model to estimate the embolic effect. RESULTS: By scanning electron microscopy and phase-contrast microscopy, MFC appears fibriform and has various sizes and an irregular surface. Gelfoam is of uniform size and has a smooth surface. PVA materials are granulated and have a rough surface. MFC is somewhat suspendable and its shape changes moderately after suspension. Gelfoam is very suspendable and its shape changes rapidly. PVA showed only mild swelling. The embolic effect of MFC was the lowest of the materials examined. Large PVA particles (250 to 500 microns) showed a lesser embolic effect than Gelfoam or small PVA particles (50 to 150 microns) or medium-sized PVA particles (150 to 250 microns). No significant differences were observed among the embolic effects of Gelfoam, small PVA particles (50 to 150 microns), and medium PVA particles (150 to 250 microns). CONCLUSIONS: MFC and large PVA particles (250 to 500 microns) should be used for embolization of vascular anatomy involving potentially dangerous anastomoses. Gelfoam, PVA particles of 150- to 250-micron diameter, and PVA particles of 50- to 150-micron diameter are adequate for embolization involving homogeneous and peripheral anatomy.

Animals↗
PubMed1996

Differences in bull spermiograms using eosin-nigrosin stain, feulgen stain, and phase contrast microscopy methods.

The Society for Theriogenology recently adopted a minimum standard of 70% normal spermatozoa for the bull breeding soundness examination (BSE). We conducted this study to determine if spermiograms derived by brightfield microscopy of eosin-nigrosin stained semen smears (Society method) overestimated the proportion of normal spermatozoa. Comparison of the above method was made with that of phase contrast microscopy (Phase method). We then evaluated our ability to discern head abnormalities by comparing brightfield microscopy of Feulgen-stained sperm DNA (Feulgen method) with those of the Society and Phase methods. Spermiograms were determined for each of the 181 beef bulls using all 3 methods. Only bulls that were being routinely tested prior to the 1993 breeding season were included. The mean percentage of normal spermatozoa surpassed the minimum standard with the Society (72.8%) but not the Phase (52.5%) method, which identified more distal cytoplasmic droplets that adhered to cells without distal midpiece reflexes. The Phase method also identified more total primary and fewer primary head abnormalities. We conclude that the Phase method is not a suitable substitute for the Society method when applying the minimum standard during a routine BSE. The Feulgen method identified more head abnormalities, especially in the pattern of DNA, than the other methods, however, when compared to the minimum standard that improvement was not clinically important. Both the Phase and Feulgen methods are better than the Society method for monitoring changes in abnormal spermiograms over time.

Journal Article↗
PubMed1996

Application of the principle of optical phase-contrast microscopy to velocity phase-encoded MRI of blood flow in the aorta.

A new method of presenting magnetic resonance phase information is described and an example of its application given in the context of velocity phase-encoded MRI of blood flow in the aorta. The method takes as its starting point Zernike's technique of phase contrast microscopy. It exploits the parallel between the transform plane in Fourier optics and kappa-space in MRI. In the example described two datasets are acquired, one with and the other without velocity encoding, as in conventional phase-encoded velocity imaging. A dataset is formed which is corrected for unwanted phase variations caused by static field inhomogeneity. The method then effectively combines phase and magnitude information into a single image. The technique is complementary to existing methods of displaying phase information.

Aorta↗
PubMed1968

Interference contrast and phase contrast microscopy of sporulation and germination of Bacillus megaterium.

The techniques of Nomarski interference contrast microscopy and phase-contrast microscopy were compared for their utility in monitoring sporulation and germination in Bacillus megaterium. The Nomarski technique permitted rapid and easy delineation of septation and engulfment during sporulation, whereas with phase contrast microscopy these stages were not detected at all. The later stages of sporulation were easily seen by either technique. Thus, of the seven stages of sporulation as recognized by the electron microscopy of thin sections, five can now be routinely detected quantitatively by optical microscopy: septation (stage II), engulfment (stage III), phase-dark forespore (corresponding to cortex formation, stage IV), phase-bright spore in a sporangium (corresponding to coat formation, stage V), and the free spore (stage VII). This means that now only stage I (axial filament) and stage VI (maturation of the refractile spore) require electron microscopy for routine detection. There was no advantage in using Nomarski optics for germination studies.

Bacillus megaterium↗
PubMed2001

A study of demyelination of nerve fibers using dynamic phase contrast microscopy.

Dynamic phase microscopy was used for evaluation of changes in myelinated axon segment in the paranodal region of nerve fibers during demyelination. Normally paranodal myelin sheath is characterized by regular oscillations of the optical path difference with frequences of 4.2 and 6.7 Hz. Demyelination decreased the amplitude and conduction velocity in nerve fibers and shifted the characteristic frequencies of optical path difference oscillations to 2.8, 3.2, and 11 Hz. These shifts of optical path difference frequencies probably resulted from disturbances in the state of charged phospholipids and a decrease in the level of bound Ca(2+)during demyelination of nerve fiber.

Animals↗
PubMedDate not supplied

[Use of phase contrast microscopy in periodontology].

Dark field microscopy and phase contrast microscopy allow subgingival microbial plaque examination to differentiate healthy state and pathogenic stages of periodontal disease. These microbial technics are appropriate to inform the patients about the bacterial etiology of their periodontitis and motivate them for a better oral hygiene.

Dental Plaque↗