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PubMed1978

[Phase contrast microscopy studies of the urine of newborn infants].

Phase contrast microscopy allows a much better identification of the urinary sediment constituents than conventional bright field microscopy. The urinary sediment of 100 neonates admitted in a care unit has been examined by phase contrast microscopy. In all cases, squamous cells are far more numerous in newborn girls than in boys. An important rate of abnormal sediments has been observed: in 40 patients cytologic symptoms of renal ischaemia have been observed (hyaline or granulous casts and renal tubular cells, but red blood cells are uncommon). Numerous uric acid cristals were persent in 22 newborns, in correlation with a prolonged perinatal hypoxia. A considerable bacteriuria was seen in 21 neonates, without concomitant leucocyturia. In conclusion, only 20% of the investigated neonates had a normal urinary sediment.

Bacteriuria↗
PubMed1984

Automated analysis of living cells through the quantitative use of automated phase contrast microscopy.

A simplified theory of image formation in phase contrast microscopy is presented. It is shown that the phase shift induced in light (related to the refractive index) by the observed object can be reconstructed, point by point, from the phase-contrast digitally sampled image through an appropriate algorithm. This allows one to make quantitative observations on unstained, living cells.

Animals↗
PubMed1982

Detection of glomerular bleeding by phase-contrast microscopy.

Midstream urine specimens from 303 consecutive patients with haematuria were examined with phase-contrast microscopy to determine whether the source of the haematuria could be predicted on the basis of urinary red-cell morphology. In 253 patients a definite diagnosis was made but the data for the other 50 were inadequate to allow a definite diagnosis. With phase-contrast microscopy the origin of haematuria was considered to be glomerular in 120 patients (115 had proven glomerulonephritis and 5 had lesions of the lower urinary tract) and non-glomerular in 105 patients (100 had lesions of the lower urinary tract and 5 had proven glomerulonephritis). A mixed picture of glomerular and non-glomerular red cells was seen in 28 patients, most commonly in association with IgA nephropathy and renal calculi. The assessment of urinary red-cell morphology by means of phase-contrast microscopy can add importantly to clinical information and, together with the presence of red-cell casts and protein in the urine, can help the clinician decide on initial investigations in patients with haematuria.

Erythrocytes↗
PubMed2003

[Clinical use of phase-contrast microscopy in the differential diagnosis of microhematuria].

AIM: To evaluate phase-contrast microscopy in differential diagnosis of asymptomatic microhematuria in patients with asymptomatic microhematuria during the 1993-2000 period. PATIENTS AND METHODS: The study was performed at the Laboratory of Cytology, Department of Nephrology and Dialysis, Rijeka University Hospital Center, Rijeka, Croatia, and included 526 patients with asymptomatic hematuria referred from Urology Department. MAIN OUTCOME MEASURES: Presence of red blood cells (RBC), other cell types, other elements, and detritus. According to size and shape, RBCs were classified into 2 main categories: dysmorphic and isomorphic RBCs. The presence of > 80% of dysmorphic RBCs was recognized as glomerular hematuria. Isomorphic cell predominance was classified as postglomerular hematuria, and equal presence of both types was considered as mixed hematuria. RESULTS: Glomerular hematuria was found in 238 (45.2%), postglomerular hematuria in 181 (34.4%) and mixed hematuria in 22 (4.2%) patients. Additional diagnostic procedures in patients with glomerular hematuria included renal biopsy. In 89% of those patients glomerular disease was found. CONCLUSION: Phase-contrast microscopy is a simple, noninvasive and reliable diagnostic procedure in nephrology practice.

Adolescent↗
PubMed1988

[Phase contrast microscopy demonstration of glomerular erythrocytes in urine: practicable in ambulatory practice?].

The use of phase-contrast microscopy in microhematuria, as proposed in 1979 by Birch and Fairley, renders morphological changes in red cells easily detectable and makes it possible to distinguish glomerular from non-glomerular bleeding. The aim of this study was to evaluate the practicability of this method as a routine laboratory test in ambulatory care. 60 patients with asymptomatic microhematuria (greater than or equal to 2 erythrocytes per high power field) were followed up over a one-year period. All patients were investigated by intravenous pyelography, ultrasound of urinary tract and three cytological examinations of the urine. The description of urine samples was done with phase-contrast microscopy by a first investigator at the beginning of the study and by a second after 12.8 months, blinded to clinical results and previous examinations. In 21 patients a definitive diagnosis was possible. In 18 patients the morphologic descriptions of the two investigators correlated with the clinical results. Only in two patients with established diagnosis there were differences between the urine description of the two investigators, and in one patient the interpretations of both investigators were wrong. These incorrect descriptions concerned patients with low-grade microhematuria. Thus, phase-contrast microscopy is a practicable method for the practitioner's use as a routine laboratory investigation. In low-grade microhematuria the method seems to be of minor value.

Ambulatory Care↗
PubMed1982

A simple quantitative analysis of phase contrast microscopy, not restricted to objects of very low retardation.

A simple vector analysis of the diffraction of light by an ideal, extended phase grating suggests that irrespective of the amount of retardation imposed on the light passing through a transparent microscopic object the diffracted light leaving the object plane is precisely 90 degrees out of phase with the resultant direct (zero-order diffracted) light. In positive phase contrast microscopy, with a 90 degrees phase plate of transmittance T for the direct light, the image and halo respectively have intensities relative to the original illumination of (square root T.cos 1/2 phi - sin 1/2 phi)2 and (square root T.cos 1/2 phi + sin 1/2 phi)w. The empty background has an apparent intensity of T. Zero intensity of the image is seen if T = tan2(1/2 phi), and reversal of contrast if T less than tan2(1/4 phi). The same equations can be used to predict the intensities of the image and halo in negative phase contrast microscopy, if phi is replaced by (360 degrees - phi). Unlike the 'standard' description of phase contrast microscopy, exemplified by Barer's vector method, the present account is consistent with the conservation of energy and is not restricted to very small object retardations. Barer's method is, however, theoretically valid for objects of any shape, and the two approaches may perhaps be regarded as complementary.

Mathematics↗