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Results for “Microscopy, Phase-Contrast”

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At least 631 records · Page 35Linked to original sources
PubMed1975

[Demonstration of immunoglobulin determinants on lymphocyte surfaces by membrane immunofluorescence].

Isolated lymphocytes from peripheral blood of 22 healthy donors were examined with the help of the indirect membrane immunofluorescence (MIF) for immunoglobulin determinants on the surface of the cells. The quantity of MIF+-cells for IgM was on the average 8.7% (3-18) and for IgG 15.5%(8-18). Five different anti-IgM-sera were characterised with regard to their use in the MIF (precipitation titre, entire protein content, content of anti-IgM-antibodies). Differences in the quantity of the MIF+-lymphocytes were above all based on differing antibody concentrations of the sera. It was referred to further possible causes for these differences. The influence on the results of the examinations by protein addition and trypsination.

Adult↗
PubMed1975

[Cytotoxic effects of a leukocidin from Staphylococcus aureus (author's transl)].

In an attempt to improve the assay of leukocidin from Staphylococcus aureus a combined vital fluorochrome staining procedure with acridine organe and ethidium bromide was developed. It proved to be more suitable for the demonstration of leukocidic effects on leukocytes than phasecontrastmicroscopy. Damaged leukocytes fluoresced distinctly red and undamaged leukocytes green. With the fluorochrome-method leukocidic changes became also evident in some lymphocytes. These were not clearly demonstrated by phasecontrastmicroscopy.

Acridines↗
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↗
PubMed1976

Cell separation using fluorescence emission anisotropy.

The emission anisotropy of selected fluorescent probes which interact with cells and their membranes is a sensitive parameter for studying the structural changes associated with different functional states. Such measurements can now be made on individual living cells at rates of up to 103 per second and the cells separated on the basis of the anisotropy function alone or combined with other physical signals using a multiparameter automated computer-controlled cell separator (MACCS). Thus, selection can be on the basis of simple or complex algorithms reflecting the size, macromolecular content, and rotational mobility of cellular components or liganded reporter molecules. Cells isolated in this manner are sterile, viable, and can be used for outgrowth or biochemical studies related to dynamic changes occurring during differentiation or malignant transformation.

Animals↗
PubMed1977

[Fluorescence microscopy demonstration of mitochondria in tissue culture cells using berberine].

The possibility of fluorescence microscopical examination of mitochondria in living animal cells using fluorochrome berberine sulphate is shown. At concentrations of 30--50 g per ml the chemical is accumulated selectively in mitochondria of living cells. The specificity of berberine sulphate accumulation in mitochondria was shown by comparative phase contrast and fluorescence microscopy. The advantages of the method is its high sensitivity and simplicity, especially when mitochondria can not be examined by the phase contrast microscopy.

Animals↗
PubMed1977

[Methods for the biological testing of dental materials on cell cultures].

This paper discusses some of the methods used by for making basic biological tests of stomatological materials. Although we do not dispense with the use of methods based upon the observation of fixed and, possibly, stained cells and allowing the states assumed by cells in a certain period of time to be noted, yet we believe that far better results may be obtained from tests enabling the development of changes of living cells cultivated in vitro to be followed. The results of the experiments conducted by the authors indicate that it is possible for the final effect to be modified in dependence upon the type of material used, its concentration, or the time allowed to elapse from the preparation of the particular material and that an observation of living cells procides much more information about the character of alterations and, more specifically about the time course of changes. If necessary, this method may be supplemented by an electronmicroscopical analysis of the changes produced.

Cells, Cultured↗
PubMed1976

The effects of methyl (5-(2-thienylcarbonyl)-1H-benzimidazol-2-yl) carbamate, (R 17934; NSC 238159), a new synthetic antitumoral drug interfering with microtubules, on mammalian cells cultured in vitro.

Ultrastructural investigations on mammalian cells cultured in vitro show that R 17934, a new synthetic anticancer drug, interferes with the structure and function of microtubules, both in interphase and mitotic cells. The activity of this compound in a wide range of experimental tumor systems can thus be explained partly as a direct antimitotic effect and partly as the disintegration of the normal subcellular organization of the nondividing cells. Preliminary investigations in experimental animals show that malignant cells are more susceptible to the antimicrotubular effect of R 17934 than are the nonmalignant cells of the host.

Antineoplastic Agents↗
PubMed1976

Conditional spore cortex-less mutants of Bacillus sphaericus 9602.

Lysine-requiring mutants of Bacillus sphaericus 9602 were isolated and classified into three groups by their mutation site in the pathway of lysine biosynthesis. The Group I mutant lacks meso-alpha, epsilon-diaminopimelic acid (meso-Dap) decarboxylase activity, but Group II and III mutants have a normal level of Dap decarboxylase activity. A Group II mutant makes dipicolinic acid from an intermediate in the lysine pathway, but Group III mutants do not. In the absence of meso-Dap in the culture, muramic lactam content in the spore cortex of Group II and III mutants is very low, compared to the wild type content. Addition of meso-Dap to the culture causes an increase of muramic lactam content. Since meso-Dap is detectable only in the spore cortex of B. sphaericus 9602, almost all of the muramic lactam in the spore is probably also located in the cortex. Group I mutants grown in the presence of L-lysine sporulate normally. Group II and III mutants produce oval and nonrefractile spores under the same conditions but the addition of meso-Dap to the culture results in the production of round and refractile spores. Thus, the presence of cortex in the spore is essential to give the round and refractile spores in B. sphaericus. The presence of cortex is also required for the accumulation of dipicolinic acid in the sporulating cells. Furthermore, 1-octanol resistance of the spore depends only on the presence of cortex but both cortex and dipicolinic acid are required for heat resistance of the spore.

Bacillus↗
PubMed1976

Ultrastructure of lymphocyte tumor cell interaction with localization of cell-bound antibody by ferritin labeling.

Splenic lymphocytes derived from Walker carcinoma-bearing rats were harvested and incubated with Walker carcinoma cells growing in tissue culture. The sequence of events leading to target cell death was studied by phase microscopy and scanning and transmission electron microscopy. The sensitized lymphocytes adhere to the tumor cells by multiple cytoplasmic appendages, but no ultrastructural changes are seen at this interface. After 1 hr these lymphocytes release cytoplasmic components consisting of membrane-lined vesicles, cell membranes, endoplasmic reticulum, and cytoplasmic material. This material adheres closely to the surface of the tumor cells and is subsequently seen within the cytoplasm of the tumor cell. The tumor cells then undergo degenerative changes and cell death occurs in 24 to 36 hr. The lymphocyte-derived material appears to contain immunoglobulin components as determined by specific ferritin labeling.

Animals↗
PubMed1976

Scanning electron microscopy of surface features of hamster embryo cells transformed in vitro by X-irradiation.

Scanning electron microscope studies were carried out on Syrian hamster embryo cells transformed in vitro by X-irradiation (300 rads) (X-ray transformed) and on normal nonirradiated and irradiated nontransformed controls. Transformed cells appeared in scanning electron microscopy as pleomorphic, thick cells piling up over each other and exhibiting extensive surface features consisting of microvilli, blebs, and ruffles. These surface structures were seen on single as well as on densely cultured transformed cells during both interphase and mitosis. The complex surface was observed shortly after transformation (on cells of a 20-day-old clone) and seems a permanent feature of the X-ray-transformed cells (present after 8 years in culture). All controls appeared by scanning electron microscopy as regular, flat, and smooth cells which grew in high-density cultures to seemingly contact-inhibited monolayers. During mitosis the normal cells (control, nontransformed) displayed surface excrescences similar to those of the transformed cells making the mitotic normal cells indistinguishable from transformed cells. The complex surface features in the normal cells were temporary and reversed back to characteristic smoothness upon reentrance into interphase.

Agglutination↗
PubMed1976

Utilization of exogenous GDP-mannose for the synthesis of mannose-containing lipids and glycoproteins by oviduct cells.

Suspensions of oviduct cells were prepared by subjecting oviduct tissue to sequential incubations with EDTA, alpha-chymotrypsin, and crude collagenase, followed by a final incubation with EDTA. Cells isolated in this way incorporate mannose from exogenous GDP-mannose into mannosyl-lipid, oligosaccharide-lipid, and glycoprotein(s). Based on several criteria, the mannosyl-lipid is identical with mannosyl-phosphoryldolichol. Similarly, the oligosaccharide-lipid appears to be identical with the oligosaccharide-lipid synthesized in vitro (Lucas, J. J., Waechter, C. J., and Lennarz, W. J. (1975) J. Biol. Chem. 250, 1992-2002). In contrast, the glycoproteins are much lower in molecular weight than those labeled in cell-free preparations. Using intact oviduct cell suspensions it was found that: (a) exogenous GDP-mannose, not its breakdown products, serves as the direct mannosyl donor; (b) experiments using mixtures of known proportions of broken and intact cells, as well as studies with metabolic inhibitors, indicate that greater than 50% of the observed incorporation of mannose from GDP-mannose was catalyzed by enzymes associated with intact cells, rather than broken cells or membrane fragments; (c) incorporation of mannose from GDP-mannose into the mannosyl acceptors does not require energy and proceeds without significant uptake of GDP-mannose into trichloroacetic acid-soluble components of the cells; (d) under conditions where labeled guanosine incorporation into nucleic acids is readily detected, no incorporation of the guanosine moiety of [3H]GDP-mannose is observed. These results indicate that the enzymes catalyzing synthesis of lipid-linked intermediates involved in glycoprotein synthesis are not only associated with intracellular membranes, but with the plasma membrane as well.

Animals↗
PubMed1976

[Balantidium coli infection of the female genitals (author's transl)].

Two cases of therapy-resistant fluorine are reported in which Balantidium coli from the class of the cilia (Ciliophora, Ciliata, Infusoria) was identified. After a personal experiment, the Balantidia must be considered extremely pathogenic. In international literature, no further indication of a ciliata infection of the female genitals was found.

Adult↗