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A comparison of phase contrast microscopy and an immunofluorescence test for the detection of Giardia spp. in faecal specimens from cattle and wild rodents.

As part of a study on the presence of Giardia cysts in water, a commercial direct immunofluorescence (DIF) test for the cysts was evaluated and compared to phase contrast microscopy. Forty faecal samples were collected from cattle; 31 contained Giardia. All 31 samples were positive by DIF whereas only 17 were detected by microscopy. The detected Giardia cysts were identified as belonging to the G. duodenalis group. 216 faecal samples were collected from wild rodents (Apodemus flavicollis, A. sylvaticus and Clethrionomys glareolus); 103 contained Giardia. Cysts were detected in 97 samples by DIF and in 57 by microscopy; 51 samples were positive by both methods. Nineteen rodents harboured cysts which morphologically resembled G. duodenalis. Specific identification was possible only by phase contrast microscopy, but the results suggested that DIF was superior for the detection of Giardia cysts in faeces of the animals tested.

Animals↗
PubMed1972

Germination and outgrowth of single spores of Saccharomyces cerevisiae viewed by scanning electron and phase-contrast microscopy.

Single spores of Saccharomyces cerevisiae were examined during germination and outgrowth by scanning electron and phase-contrast microscopy. Also determined were changes in cell weight and light absorbance, trehalose utilization, and synthesis of protein and KOH-soluble carbohydrates. These studies reveal that development of the vegetative cell from a spore follows a definite sequence of events involving dramatic physical and chemical modifications. These changes are: initial rapid loss in cellular absorbance followed later by an abrupt gain in absorbance; reduction in cell weight and a subsequent progressive increase; modification of the spore surface with concomitant diminution in refractility; elongation of the cell and augmentation of surface irregularities; rapid decline in trehalose content of the cell accompanied by extensive formation of KOH-soluble carbohydrates; and bud formation.

Carbohydrates↗
PubMed1991

[Value of phase-contrast microscopy in differential diagnosis of erythrocyturia].

In 41 patients with erythrocyturia the usefulness was assessed of phase-contrast microscopy of erythrocytes in urinary sediment. In all 28 patients with non-glomerular erythrocyturia (less than 20% of changed sediment erythrocytes) non-glomerular, mainly urological, causes of erythrocyturia were found. In 13 cases of glomerulonephritis confirmed by biopsy erythrocyturia was in 6 cases of glomerular character (greater than 60% of changed sediment erythrocytes), in the remaining 7 cases it was of mixed character (greater than 20-60% of changed sediment erythrocytes). In cases of glomerulonephritis a correlation was found between the per cent of changed sediment erythrocytes in this microscopy and the severity of glomerulopathy and the coexistence and intensity of interstitial-tubular changes in renal biopsy. The accepted mode of differential diagnosis of erythrocyturia includes presently renal biopsy in case of glomerular erythrocyturia and undertaking of urological diagnostic procedures in case of non-glomerular erythrocyturia. In case of mixed erythrocyturia the diagnostic procedure is as yet as in non-glomerular erythrocyturia. This will be eventually changed when our experience will increase.

Adolescent↗
PubMed1950

Studies on the life cycle of spirochetes; the life cycle of the Nichols pathogenic Treponema pallidum in the rabbit testis as seen by phase contrast microscopy.

A series of observations with the phase contrast microscope on the occurrence of a complex life cycle in the pathogenic Treponema pallidum as it occurs in the syphilitic rabbit testis has been presented and it seems likely from these observations that there are two means of vegetative reproduction, consisting of (1) transverse division (the most important under usual conditions); and (2) the production of gemmae or buds which eventuate into unispirochetal cysts comparable to those described for saprophytic forms, within each of which single spirochetes develop and differentiate, and from which they subsequently emerge. In addition preliminary evidence is presented which suggests that a more complex process is involved in which multispirochetal cysts develop following aggregation of two or more organisms. Within each of these larger cysts numerous organisms develop and subsequently emerge as tangled ropes. Following emergence, they subsequently undergo transverse division and gemmae formation, and so reproduce vegetatively. Subsequent papers will elaborate upon these processes.

Animals↗
PubMed1979

The lamina splendens of articular cartilage is an artefact of phase contrast microscopy.

The so-called lamina splendens of articular cartilage is shown to be a characteristic of phase contrast microscopy; this technique provides no evidence for an anatomically distinct surface layer. Fresnel diffraction occurs at edges separating regions of different refractive indices. These diffraction effects, when viewed under phase contrast, lead to the appearance of a bright line along the edge.

Adolescent↗
PubMed1976

Lymphocyte locomotion. II. The lymphocyte traffic over the post-capillary venules analysed by phase contrast microscopy of thin sections of rat lymph nodes.

Thin sections of lymph nodes from 14 rats were examined by phase contrast microscopy as regards direction of lymphoctes with amoeboid movement configuration (AMC) relative to the basement membrane of post-capillary high-endothelium venules (HE-cenules). Out of 118 lymphocytes with AMC, 82 appeared to be on theyr way into the venule from the lymph node parenchyma. This observation suggests that the lymphocyte traffic over the HE-venules is bi-directional, with the main migratory stream of lymphocytes from the lymph node parenchyma into the post-capillary venules.

Animals↗