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PubMed1984

The use of subcutaneously implanted araldite disks for microstructural studies of inflammatory macrophages.

Subcutaneously implanted epoxy resin disks can be used instead of glass coverslips in mice to recruit inflammatory macrophages. Implanted araldite disks exhibited large numbers of macrophages on both surfaces which could be observed conveniently by light and phase contrast microscopy. Most importantly, the disks can be embedded directly in an araldite mixture for the preparation of thin sections for electron microscope examination.

Animals↗
PubMed2005

pH-Induced structural transitions during complexation and coacervation of beta-lactoglobulin and acacia gum.

pH-Induced structural changes during complex coacervation between beta-lactoglobulin (BLG) and Acacia gum (AG) in aqueous solutions were determined by coupling slow in situ acidification of BLG/AG mixed dispersions and different experimental methods. The combined signal evolution of dynamic light scattering at 90 degrees scattering angle (I(90)), electrophoretic mobility, turbidimetry (tau), circular dichroism, and phase contrast microscopy allowed the distinction of critical structural transitions and the definition of their corresponding pH. The formation of soluble BLG/AG complexes was initiated at pH(sc) (4.90), since I(90) and tau significantly increased from the baseline. In parallel or just following complexation, a conformational change of BLG was detected at pH(pct) (4.8). An increase in positive charge density of BLG induced complex aggregation at pH(ca) (4.7). More efficient charge neutralization of aggregated complexes, especially through the lowering of the number of AG negative charges, promoted initiation of phase separation at pH(psi) (4.4). Mixed dispersions became unstable and phase separation occurred at pH(ps) (4.2). The phase separation of mixed dispersions was suggested by the maximum value of scattered light, by an important acceleration of the dispersion turbidity, by a strong increase of hydrodynamic radii, and by the first appearance of light fluctuations as observed by phase contrast microscopy. At the microscopic level, the first coacervates were observed at pH(coa) (4.0), near the pH of the maximum of turbidity. It was also noticed that, from the onset of interactions between biopolymers, the pH decrease led to (i) a gradual homogenization of particle size in the mixed dispersion as suggested by the decrease of dispersion polydispersity and (ii) conformational transitions of the protein (a loss of alpha-helix structure at pH(pct) and a gain in protein secondary structure near pH(coa), probably involving beta-sheet components).

Acacia↗
PubMed1996

Metabolites of 5-fluorouracil, alpha-fluoro-beta-alanine and fluoroacetic acid, directly injure myelinated fibers in tissue culture.

The neurotoxicity of two 5-fluorouracil (5-FU) derivatives, tegafur (FT) and carmofur (HCFU), which selectively induce leukoencephalopathy involving the cerebral white matter in humans and vacuolation of myelinated fibers in dogs and cats, was examined in vitro. The common metabolites of these drugs, alpha-fluoro-beta-alanine (FBAL) and fluoroacetic acid (FA), were added to the medium of cultured murine cerebellar myelinated fibers. On day 1 of exposure to 7 microM FBAL and FA, which corresponds to their blood concentrations 2 h after oral administration of 10 mg.kg-1 HCFU to dogs that induced central nervous system vacuolation after 30 days, partial splits of the myelinic intraperiod line were observed by electron microscopy. On days 4-7, phase contrast microscopy revealed spindle-shaped swelling and granulation of myelin and electron microscopy demonstrated prominent dissociation of the myelinic intraperiod line with monolocular and multilocular vacuolation. More severe changes, such as myelin loss, were found in cultures exposed to a higher concentration (70 microM) of FBAL and FA, but no remarkable neuronal, astrocytic or oligodendrocytic changes occurred. Quantitative evaluation of myelin injury by electron microscopy revealed significant toxicity of FBAL and FA, at concentrations of 7 and 70 microM, on day 4. However, groups treated with 0.7 microM FBAL and FA, 5-FU (7 microM) and controls exposed to beta-alanine and acetic acid concentrations of 0.7, 7 and 70 microM showed no marked injury. We concluded that these anticancer drug metabolites injure myelin fibers directly, resulting in vacuolation due to myelin splitting and destruction.

Animals↗
PubMed1986

Experimental gingivitis in relation to susceptibility to periodontal disease. II. Phase-contrast microbiological features and some host-response observations.

In the present investigation, a number of histological and immunohistochemical characteristics of periodontal tissues as well as the phase-contrast microscopy of dental plaque were studied after experimentally-induced gingival inflammation in relation to susceptibility to periodontal disease. The study included a younger (mean age 34.1 years) and an older age group (mean age 48 years) with a reduced but healthy periodontium. Both age groups had the same amount of loss of attachment which may suggest that they had different degrees of susceptibility to periodontal disease. At the start of the experiment, each patient was instructed to abstain from oral hygiene in one quadrant of the mouth for a period of 18 days. At the end of the 18-day period, supra-gingival plaque and gingival tissue samples were taken. As determined by phase-contrast microscopy, the plaque samples of both age groups contained relatively high proportions of spirochetes. This may indicate that the patients are at risk for recurrence of periodontal breakdown. The general histopathologic picture of the gingival tissue samples of both age groups was similar to the so-called 'early lesion'. However, IgA-producing plasma cells were found in most tissue samples of both age groups. The first part of this study showed that the younger, in comparison to the older, patients developed inflammation in terms of bleeding on probing more rapidly. These clinical results cannot be explained by the host-parasite parameters investigated in the present study.

Adult↗
PubMed1975

Langerhans cells in tissue cultures of guinea-pig epidermal cells.

Dispersed cell cultures of guinea-pig epidermis have been maintained for up to 36 days. The progress of these cultures has been studied by phase contrast microscopy, the adenosine triphosphatase reaction, and cinephotomicrography. Langerhans cells have been identified and their behaviour studied, particularly in relation to keratinocytes.

Adenosine Triphosphatases↗
PubMed1959

The occurrence of intercellular bridges in groups of cells exhibiting synchronous differentiation.

A previous electron microscopic study of the cat testis revealed that spermatids derived from the same spermatogonium are joined together by intercellular bridges. The present paper records the observation of similar connections between spermatocytes and between spermatids in Hydra, fruit-fly, opossum, pigeon, rat, hamster, guinea pig, rabbit, monkey, and man. In view of these findings, it is considered likely that a syncytial relationship within groups of developing male germ cells is of general occurrence and is probably responsible for their synchronous differentiation. When clusters of spermatids, freshly isolated from the germinal epithelium are observed by phase contrast microscopy, the constrictions between the cellular units of the syncytium disappear and the whole group coalesces into a spherical multinucleate mass. The significance of this observation in relation to the occurrence of abnormal spermatozoa in semen and the prevalence of multinucleate giant cells in pathological testes is discussed. In the ectoderm of Hydra, the clusters of cnidoblasts that arise from proliferation of interstitial cells are also connected by intercellular bridges. The development of nematocysts within these groups of conjoined cells is precisely synchronized. Both in the testis of vertebrates and the ectoderm of Hydra, a syncytium results from incomplete cytokinesis in the proliferation of relatively undifferentiated cells. The intercellular bridges between daughter cells are formed when the cleavage furrow encounters the spindle remnant and is arrested by it. The subsequent dissolution of the spindle filaments establishes free communication between the cells. The discovery of intercellular bridges in the two unrelated tissues discussed here suggests that a similar syncytial relationship may be found elsewhere in nature where groups of cells of common origin differentiate synchronously.

Animals↗
PubMed1987

Light-microscopical appearance and ultrastructure of Blastocystis hominis, an intestinal parasite of man.

A study on Blastocystis hominis was undertaken for the purpose of clarifying the morphology of the organism using the following techniques; Giemsa, Heidenhain Iron Hematoxylin, and DAPI stains, phase-contrast microscopy, and transmission- and scanning-electron microscopy. Microscopic examinations of the lumen fluids aspirated at the endoscopical examination revealed the habitation of B. hominis in the lower ileum and cecum of a patient. When examined light-microscopically, organisms from stool materials, cultures, and aspirated intestinal lumen contents of a patient showed morphological resemblances to each other except for variations in size. Vacuolated cells, which were spherical in shape and characteristically had a large central vacuole and a narrow rim of cytoplasm containing nuclei and some inclusions, were the only form of the organism observed in this study, although the contents of the vacuole notably varied. DAPI stains clearly revealed the nucleus and the possible mitochondrion in the narrow rim of cytoplasm. Phase-contrast microscopy of fresh material prepared with physiological saline was recommended for diagnosis. When examined electron-microscopically, the organisms were coated with a capsule that was composed of fine filamentous materials. All the organisms contained a central vacuole although the contents of it varied considerably. The cytoplasm gave the organism a signet ring appearance and contained cristate mitochondria, a great number of ribosomes, Golgi's apparatuses, cytoplasmic microtubules, and nuclei with a nucleolus. Very few of the ultrastructures are those that would be expected of a yeast. Recent occurrences of B. hominis infection in Kyoto City, Japan, during a two-year period (June 1983 to August 1985) were also reported.

Animals↗
PubMed1994

Effects of Sr-hydroxyapatite microcrystal on cultured cell.

Strontium-hydroxyapatite microcrystals (Sr-HAp sol) were produced by a wet method at room temperature with ultrasonic irradiation and were applied to MC3T3-E1, ROS, and L cells for periods of 2, 4, and 6 days in vitro. The effect on cell growth, the variation of LDH and Ca contents in the media, and attachment between cell and microcrystal were investigated. Sintered Sr-HAp and HAp sol were used as controls. A slight inhibitory effect of Sr-HAp sol on cell growth was found. The degree of inhibition was nearly the same as HAp sol. However, it was stronger than sintered Sr-HAp. The contents of LDH in the media increased with the degree of cell inhibition, and the contents of Ca in the media decreased from the initial stage of cell-sol contact. A good attachment of Sr-HAp sol to cultured cells was seen by phase-contrast microscopy and SEM.

Animals↗
PubMed1992

[The characteristics of hematuria in chronic glomerulonephritis and nonglomerular diseases of the kidneys and urinary tract].

Upon the analysis of qualitative and quantitative characteristics of hematuria in renal and urinary tract affections it was established that whatever the red blood cell count in the urine, hematuria is primarily glomerular in contrast to nonglomerular in chronic glomerulonephritis and nonglomerular diseases of the kidneys and urinary tracts, respectively. Morphologic studies of urinary red blood cells using phase-contrast microscopy proved a valuable tool for identification of hematuria origin.

Chronic Disease↗
PubMed1977

[Morphological diagnosis of Pneumocystis carinii].

Pneumocystis carinii pneumonia can only be diagnosed once the microorganism is demonstrated. The authors review and illustrate various staining technics, and discuss for each of them specific advantages. All samples must by systematically examined both by phase contrast microscopy and by light microscopy after Gomori-Grocott and Gram-Weigert stains. This morphological study is completed by ultrastructural photographs.

Humans↗
PubMed1984

Phase separation between nucleoid and cytoplasm in Escherichia coli as defined by immersive refractometry.

The refractive indices of nucleoid and cytoplasm in Escherichia coli were derived theoretically and experimentally. For the theoretical estimates, we made use of the known macromolecular composition of E. coli B/r (G. Churchward and H. Bremer, J. Theor. Biol. 94:651-670, 1982) and of estimates of cell and nucleoid volumes. These were obtained from micrographs of living bacteria made with a confocal scanning light microscope. The theoretical values were calculated, assuming that all DNA occurred in the nucleoid and that all protein and RNA occurred in the cytoplasm. Comparison with experimental refractive index values directly obtained by immersive refractometry showed that, besides its DNA, the nucleoid must contain an additional amount of solids equivalent to 8.6% (wt/vol) protein. With the nucleoid containing 6.8% (wt/vol) DNA and 8.6% (wt/vol) protein and the cytoplasm containing 21% (wt/vol) protein and 4% (wt/vol) RNA, a mass difference is obtained, which accounts for the phase separation observed between the nucleoid and cytoplasm in living cells by phase-contrast microscopy. The decrease in the refractive index of the nucleoid relative to that of the cytoplasm observed upon, for instance, OsO4 fixation was interpreted as being indicative of the loss of protein content in the nucleoid.

Chloramphenicol↗
PubMed1989

Cytotoxic effects of benzalkonium chloride and chlorobutanol on human corneal epithelial cells in vitro.

By exposing primary cultures of human corneal epithelial cells to a single dose of either benzalkonium chloride or chlorobutanol, evaluated the cytotoxicity of these two preservatives which are commonly used in artificial tear solutions and other topical ophthalmic medications. Control and experimental cultures were analyzed by continuous time-lapse videomicrographic recordings as well as by sequential phase-contrast microscopy. Both benzalkonium chloride at a concentration of 0.01% and chlorobutanol at 0.5% caused immediate cessation of normal cytokinesis and mitotic activity, and epithelial cells degenerated within two hours and eight hours, respectively.

Benzalkonium Compounds↗
PubMed2006

Analytical performance of the Iris iQ200 automated urine microscopy analyzer.

BACKGROUND: We evaluated the Iris iQ200 Automated Urine Microscopy Analyzer to find out if the instrument performed better than traditional visual bright field microscopy in detecting basic urine particles, as assessed against reference phase contrast microscopy. METHODS: The HUSLAB quality system was followed in planning and completing the evaluation process. The iQ200 instrument results from 167 mid-stream, uncentrifuged urine specimens were compared to those obtained with phase contrast reference microscopy, and to those with routine bright field microscopy. Linearity, carry-over and precision were tested according to well-established protocols. RESULTS: The iQ200 counted erythrocytes (RBC) at r=0.894 (R(2)=0.799) with Automated Particle Recognition (APR) software alone and at r=0.948 (R(2)=0.898) after re-classification. The performance for leukocytes (WBC) was r=0.885 with APR and r=0.978 after re-classification. The correlations of counting after user re-classification were r=0.927 for squamous epithelial cells (SQEP), r=0.856 for casts, and r=0.706 for non-squamous epithelial cells. The iQ200 showed good linearity and precision and no carry-over was detected. CONCLUSIONS: The Iris iQ200 was capable to count reliably RBC, WBC, and SQEP cells and to identify a fraction of bacteria and renal elements. Counting results equalled or exceeded that of routine bright field microscopy or earlier flow cytometric technology. The instrument eliminates manual sample preparation but requires a well-trained technologist for re-grouping of findings.

Automation↗
PubMed2002

Influence of calcium on Manduca sexta plasmatocyte spreading and network formation.

Plasmatocytes are a class of insect hemocytes important in the cellular defense response. In some species, they are phagocytic, protecting the insect from smaller pathogens. In many insects, they work in concert with other hemocytes (particularly other plasmatocytes and granular cells) to form nodules and to encapsulate foreign material. To perform these functions, plasmatocytes attach to, spread on, and surround suitable targets. Because of their importance, because we had previously observed that prolonged incubation of hemocytes in solutions containing the divalent cation chelator ethylenediaminetetraacetic acid (EDTA) inhibited plasmatocyte spreading, and because of the importance of divalent cations in many immune-related functions, we investigated the effect of calcium and magnesium on spreading of plasmatocytes from fifth instar Manduca sexta larvae. On glass slides, plasmatocytes spread more quickly and elongated in Grace's medium containing 5 mM calcium, compared to calcium-free medium. In the presence of calcium, plasmatocyte adhesion, spreading, and network formation were not visibly different in magnesium-free and magnesium-containing Grace's medium. Using immunomicroscopy with a monoclonal antibody specific for plasmatocytes, we measured the length and width of plasmatocytes incubated with several different concentrations of calcium. Plasmatocyte length positively correlated with calcium concentration to 5 mM (maximum concentration tested and approximately the hemolymph concentration). Mean plasmatocyte width was less in 0 and 5 mM calcium than in 0.05 or 0.5 mM calcium. On plastic, hemocytes survived longer than on glass (they survived beyond 24 h) and, in 5 mM calcium, formed an extensive network readily visible by phase-contrast microscopy. This network was never as extensive in the absence of calcium. Network formation in the absence of magnesium, but presence of calcium, resembled network formation in standard Grace's medium.

Animals↗