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Biomedical subjects

G Donelli

Publications and source records attributed to G Donelli.

At least 127 records · Page 7Linked to original sources
PubMed1987

Adherence to and penetration of cultured cells by an invasive strain of Escherichia coli: an ultrastructural study.

The penetration process of an enteroinvasive strain of Escherichia coli 0124 into HEp-2 cells has been studied by electron microscopy. Bacteria penetrated into cultured cells by a phagocytosis-like mechanism, and multiplied within the vacuoles as well as in the cytoplasmic matrix. On the whole, the infection cycle of EIEC appeared to be similar to that described for Shigella. The stain examined has also been found to elaborate a 40 nm-thick glyocalix, which is probably involved in the recognition of host surface receptors and therefore in the attachment of microorganisms to the cell membrane.

Bacterial Adhesion↗
PubMed1986

Epstein-Barr virus-related ultrastructural modifications of plasma membrane during B-cell transformation.

Ultrastructural modifications are described in the plasma membrane of in vitro established human B cells. By the freeze-fracture technique, intramembrane particles (IMPs) are quantified in B lymphocytes following Epstein-Barr virus (EBV) transformation in vitro, and in B-lymphoma (Burkitt-type) cells, either positive or negative for EBV genome. Analysis shows an overall increase in IMP density as compared to normal controls. Differences are observed between the protoplasmic and exoplasmic faces of fractured membranes as well as among in vitro transformed and clearly neoplastic cells. Results indicate that conformational changes in IMP distribution parallel neoplastic evolution of transformed cells.

B-Lymphocytes↗
PubMed1986

A study of a herpesvirus isolated from dairy cattle with a history of reproductive disorders.

Three strains of herpesvirus were recovered from cows with vulvovaginitis. The three isolates (85/BH 16TV, 85/BH 17TV, 85/BH 18TV), when compared by cross serum neutralization (SN) tests, were found to be antigenically identical. They were serologically distinct from infectious bovine rhinotracheitis (IBR) virus and Bovid herpesvirus 2 (BHV2), while they cross reacted with bovine herpesvirus DN-599. Besides the serologic aspects, the three isolates appeared to share common biological, physical and morphological properties with the newly recognized bovine herpesviruses, of which DN-599 is a representative strain.

Animals↗
PubMed1985

Electron microscopy and microprobe analysis of dialysis contaminants.

A migration of plastic particles from haemodialysis circuit to blood has been recognized to be cause of storage inflammation. Its origin from segments of silicone tubing has been demonstrated by in vivo and in vitro experiments. A similar finding with a peculiar histology picture has been observed in patients who used only PVC and PU-PVC tubing. In this case too microprobe analysis revealed the presence of silicon (Si) in fibril inclusions of liver and spleen cells. TEM, SEM and EDS of cuprophane dialyzer perfusates filtered through Nuclepore revealed the presence of particles with an intense Si Ka. The release from the dialyzer of silicon containing contaminants seems to be an additional risk for uremic patients.

Adult↗
PubMed1984

A cell division-active protein from E. coli.

A purification procedure for a protein obtained from an pathogenic strain of E. coli is described. The protein-called CNF-is active in inhibiting the duplication of cultured mammalian cells. Since nuclei division is apparently normal, treatment of cultured cells with CNF leads to the formation of gigantic, polynucleated cells. The purified protein is chromatographically and electrophoretically homogeneous. A partial characterization of CNF protein is also given.

Amino Acids↗
PubMed1984

Evaluation by electron microscopy techniques of asbestos contamination in industrial, cosmetic, and pharmaceutical talcs.

Talc powders from national and international markets were analyzed in order to assess their fiber contents and the proportion of asbestos in the fibrous material. Samples of talc powders used as excipients in pharmaceutical and cosmetic preparations demonstrated fiber contents up to 30% of total particles. About a half of the talc powders revealed the presence of asbestos: in five samples chrysotile (a serpentine asbestos) was present, in the other ones tremolite and anthophyllite (an amphibole asbestos). The amounts of asbestos vary up to 90% in the different samples of the fibrous fraction. About 75% of observed asbestos fibers were thinner than 0.4 micron, i.e., below the resolving power of light microscopy which until now was the most utilized technique for evaluating the environmental pollution due to asbestos.

Asbestos↗
PubMed1983

A study of cytopathic rotavirus strains isolated from calves with acute enteritis.

Nine cytopathic bovine rotavirus strains were isolated in MA-104 cell cultures from fecal specimens of dairy calves suffering from diarrhea. Isolation of the virus was accomplished from three outbreaks which occurred on dairy farms located in Central and Southern Italy. Fecal suspensions were treated with a high concentration (1000 micrograms/ml) of trypsin, and inoculated into MA-104 cell cultures grown out in Eagle's minimum essential medium (MEM) containing 5 micrograms/ml of the enzyme. Cytopathic effects (CPE), characterized by intracytoplasmic inclusion bodies of different sizes and shapes, were observed on the 1st passage with five of the strains and on the 2nd (2 strains) or the 3rd (2 strains) passage for the others. The presence of trypsin and the use of MA-104 cells appeared to be essential for the occurrence of CPE, inasmuch as no CPE was detected when trypsin was omitted in the MA-104 cell system. Replication failed to occur when primary bovine embryo kidney cell cultures with or without trypsin were used. Electron microscopy revealed the presence of particles with a typical rotavirus morphology. In MA-104 cells, the titre of virus reached its maximum 48 hr after inoculation. Small, clear-cut plaques were produced by the isolates in MA-104 cells under the overlay of MEM containing carboxymethyl cellulose, trypsin and DEAE-dextran. The nine rotavirus strains were antigenically related, whereas the relationship to either the Nebraska or the Compton rotaviruses was quite weak.

Acute Disease↗
PubMed1982

Human peripheral eosinophils with receptors for IgM: demonstration and ultrastructural morphology.

Receptors for IgM were detected on peripheral blood human eosinophils by a rosette technique with ox red blood cells coated with the IgM fraction of the specific immunserum. Between 14% and 43% (mean 27%) FcmuR positive cells were found after an overnight incubation period at 37 degrees C by using this technique. The specificity of the receptors for IgM was assessed by studying the inhibitory capacity of purified human IgM in the rosette assay. From an ultrastructural point of view, the EAM rosette-forming cells are mature eosinophilic granulocytes characterized by a nucleus with a variable number of lobes and a certain number of "first type" granules partially or totally devoid of their content.

Binding, Competitive↗