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Biomedical subjects

G Donelli

Publications and source records attributed to G Donelli.

At least 109 records · Page 6Linked to original sources
PubMed1989

Morphologic changes induced in vitro by 2,5 hexanedione.

The effects of 2,5 hexanedione (2,5 HD), a metabolite of n-hexane, were investigated in different in vitro systems. A human mammary carcinoma cell line, a human melanoma cell line, and fetal mouse neuronal cells in primary culture were considered. Light and electron microscopic observations demonstrated clearly that changes in cell proliferation can be detected. Furthermore, morphologic differentiative phenomena characterized by a noticeable increase in cell protrusions and dendriticlike processes can occur. Differences in the features of these processes were also detected between the different cell lines. These data can indicate non-neuronal cells as possible further targets of the toxicant. The possibility could be hypothesized that toxic neuropathies are generalized disorders, being neuronal system exceptionally vulnerable to 2,5 HD. Moreover, results obtained suggest that the sensitivity of in vitro systems could represent a useful tool in studying the mechanisms of action of the neurotoxicant 2,5 HD.

Animals↗
PubMed1989

Effects of Clostridium difficile toxins A and B on cytoskeleton organization in HEp-2 cells: a comparative morphological study.

A comparative study on the effects of toxin A and toxin B from Clostridium difficile on HEp-2 cells was carried out. Both toxins caused cell retraction and rounding and seemed to exert their effect on cell morphology via a rearrangement of actin and alpha-actinin microfilaments. Such a rearrangement occurred at an early stage, when no change in microtubular and cytokeratin systems was detectable. Nevertheless, several structural modifications accompanying the cytopathological process induced by toxins A and B appeared to be quite different. In particular, toxin B-treated cells showed an arborized phenotype as a result of cell retraction and rounding, whereas toxin A caused cell rounding without arborization. Moreover, nuclear polarization following disorganization of the microfilament system was only observed in toxin A-treated cells. The structural features distinguishing intoxication processes induced by the two toxins probably reflect a different mechanism of action and suggest the presence of a distinct subcellular component as a primary target for each toxin.

Bacterial Proteins↗
PubMed1989

Cryptosporidium as a common cause of childhood diarrhoea in Italy.

Cryptosporidium oocysts were observed in the stools of 9 (7.2%) of 124 Italian children with diarrhoea, examined during the period 1 January-31 December 1984. In two children, the parasite was associated with other enteric pathogens. The duration of diarrhoea was 2-30 days, with a median of 6 days. In all cases the infection was self limiting. The mean age of the Cryptosporidium-positive children was 34 months, and all cases occurred in the warm season. Cryptosporidium was found to be the third most common enteric pathogen after rotavirus and Salmonella spp.

Animals↗
PubMed1989

Relationship between cytotoxic necrotizing factor production and serotype in hemolytic Escherichia coli.

We examined the relationship between serotype and cytotoxic necrotizing factor (CNF) production in 123 hemolytic strains of Escherichia coli isolated from both stools and extraintestinal infections. Of 76 strains producing both hemolysin (Hly) and CNF, 66 (87%) belonged to one of six serogroups (O2, O4, O6, O22, O75, and O83). In contrast, 47 E. coli strains producing Hly only belonged to 21 different O serogroups, and only 2 of these (O6 and O18ac) were widely represented. Generally, CNF-positive and CNF-negative hemolytic isolates were assigned to different O serogroups, with the exception of O6, often present in both categories of isolates. Serogroups O4 and O18ac were significantly more prevalent among strains from extraintestinal infections than among those from stools. In contrast, the Hly-positive, CNF-negative isolates, belonging to numerous less common serogroups, were hardly ever isolated from extraintestinal infections. Serological typing further confirmed that hemolytic isolates of E. coli may grossly be divided into two main populations on the basis of the ability to produce CNF. Examination of hemolytic E. coli for this property may also be useful in achieving a more detailed characterization of pathogenic clones.

Bacterial Outer Membrane Proteins↗
PubMed1989

Four-year study of rotavirus electropherotypes from cases of infantile diarrhea in Rome.

Rotavirus infections were detected in 210 of 675 children with acute diarrhea admitted to a major pediatric hospital in Rome from January 1982 through December 1985. Most of the patients with rotavirus infections were admitted during the winter season in both 1982 and 1985, whereas during the two intermediate years, cases occurred in all months. Among 84 rotavirus samples examined, 14 different electropherotypes were recognized, 2 of which largely predominated over the others. The two electropherotypes were particularly frequent in the 2 epidemic years, altogether accounting for 70.2% of the samples typed, and circulated in distinct periods. None of the viruses showed a short pattern of electrophoretic migration of the genome, indicating a minor involvement of subgroup I rotaviruses in hospitalization-requiring diarrheas occurring in the area surveyed.

Acute Disease↗
PubMed1989

A scanning electron microscopy analysis of human cytotoxic cell subsets and of their mode of conjugation with tumor cell targets.

In this study we describe the surface features of non-MHC (Major Histocompatibility Complex)-restricted cytotoxic cells isolated from human peripheral blood. Purified populations of CD3-, natural killer (NK) cells were allowed to interact with NK-sensitive (K562) and NK-resistant (THP-1-0) tumor cell targets. The type of effector to target cell binding was investigated by scanning electron microscope (SEM) analysis. A different interaction with the effectors is described for NK-resistant targets in comparison with NK-susceptible tumor cells. SEM was also used to investigate the relationship between interleukin 2 (IL2)-activated cytotoxic cells (lymphokine-activated killer, LAK, cells) and the tumor targets. We also describe the unique growth features of certain clones of cytotoxic T cells expressing gamma delta antigen receptors which support the contention that these cells may have a special ability of homing into tissues. We conclude that non-specific cytotoxic cells constitute a diverse population of effectors which differ not only for the expression of surface antigens, but also for their ability to interact with tumor cell targets and to home into the peripheral tissues where they may exert their lytic functions.

Cell Survival↗
PubMed1989

Mineral fibres and dusts in lungs of subjects living in an urban environment.

We have undertaken a study on 200 autopsy lung samples collected from subjects who lived in the Rome urban area and were not occupationally exposed to mineral dusts. The samples belonged to subjects who died aged between 15 and 65, both male and female. Subjects suffering from diseases and drug addicts were excluded. The purpose of this investigation was to determine whether any correlation existed between subjects' life-style, in particular smoking habits, and the presence of mineral fibres and dusts in their lungs. The data obtained were compared with those on airborne mineral dusts in the environment of the subjects themselves, particularly data on the concentration and types of mineral fibres present in that environment.

Adolescent↗
PubMed1988

Comparison among enterotoxigenic strains of Escherichia coli isolated in Italy and Somalia.

Nine strains of ETEC isolated in Italy have been compared with 13 isolates from Somalia with respect to toxin production, serotype and antimicrobial resistance pattern. None of the strains isolated from Italy belonged to any serotype or serogroups found among the strains from Somalia. Remarkable differences between the two groups of isolates were also observed with regard to the susceptibility to antimicrobials and the presence of R-plasmids. These findings suggest that ETEC strains isolated in Italy are not related to the strains widespread in Somalia and, generally, in developing countries.

Antigens, Bacterial↗
PubMed1988

Influence of cetylpyridinium chloride on the ultrastructural appearance of sulphated glycosaminoglycans in human colonic mucosa.

The effect of adding cetylpyridinium chloride to the fixative on the preservation of sulphated glycosaminoglycans (SGs) was studied in human normal colonic mucosa. SGs were visualized at the ultrastructural level through the application of Spicer's High Iron Diamine (HID) technique followed by a post-fixation with potassium ferrocyanide-reduced osmium tetroxide. SGs were mainly localized in basement membranes of epithelium and capillary wall and along collagen fibers. The morphology of the reactive sites depended on the presence of cetylpyridinium chloride, SGs being granular in absence of the salt and more or less elongated when cetylpyridinium chloride was added to the fixative. We suggest that the use of cetylpyridinium chloride during fixation may help to preserve SG molecule at the ultrastructural level.

Cetylpyridinium↗
PubMed1988

Preservation of capsular material of streptococcal cells by specific lectins determined by immunoelectron microscopy.

We describe the use of lectins as specific stabilizing agents for the polysaccharide capsular components of two Gram-positive bacteria, Streptococcus agalactiae and Streptococcus bovis. Treatment of bacterial suspensions with wheatgerm agglutinin and concanavalin A allowed better morphological preservation as well as immunoelectron microscopic localization of a capsular component (lipoteichoic acid) by employing specific antibodies and the protein A-gold technique. Data obtained indicate that lectins are useful agents in preserving highly water-soluble capsular components during the electron microscopy procedures for both unembedded and embedded samples.

Animals↗
PubMed1988

Cytoskeletal changes induced in HEp-2 cells by the cytotoxic necrotizing factor of Escherichia coli.

The effect of the cytotoxic necrotizing factor of Escherichia coli on HEp-2 cells was studied by fluorescence and scanning electron microscopy. This cytotoxin, known for inducing the formation of giant multinucleated cells in several cell lines, caused changes in actin and tubulin organization. The presence of membrane ruffles at the cell border and of numerous thick bundles of actin crossing the cell body, suggests that the factor promotes cell spreading; this probably interferes with cytokinesis, ultimately leading to the formation of very large flattened multinucleated cells. Moreover, the nuclear segmentation observed in treated cells seems to be associated with a rearrangement of actin in the perinuclear region and with the presence of tubulin bundles in proximity to nuclear clefts. Although the primary target is still unknown, these findings suggest that the cytoskeleton is affected accounting for the multinucleation process induced by the factor.

Bacterial Toxins↗
PubMed1988

A three-year diagnostic and epidemiological study on viral infantile diarrhoea in Rome.

Rotavirus infection was demonstrated in 168 (29.3%) of 573 children hospitalized for acute diarrhoea in Rome between January 1982 and December 1984. Laboratory diagnosis of these infections was made by transmission electron microscopy and enzyme immunoassay techniques with an overall agreement of 91.3%. Astroviruses, adenoviruses and small round viruses were detected in the faeces of 36 patients (6.4%). Whereas in 1982 rotavirus positive patients were clustered in the winter and following spring, in the following years cases were recorded all year round. The median age of patients with rotavirus infections was 17, 10 and 11.5 months in 1982, 1983 and 1984, respectively. In addition, a smaller number of rotavirus positive cases were admitted in 1983 when compared to those admitted during the previous as well as the subsequent years. It is suggested that a herd immunity was induced in the population by epidemic spread of rotavirus in the first half of 1982.

Adenovirus Infections, Human↗
PubMed1988

Particle migration from haemodialysis circuit: electron microscopy and microprobe analysis.

It has been recognized that storage inflammation in organs of uraemic patients is due to silicone particle migration from tubing segments of the haemodialysis circuit to blood. Nevertheless, iatrogenic storage of foreign material containing Si has been also observed in long-term dialysis patients which, in our Unit, used only PVC or PU-PVC tubings. The origin and the nature of the particulate has been investigated in vivo and in vitro on bioptical samples as well as on cuprophan dialyser and PVC tubing eluates. This study carried out by means of TEM, SEM and microprobe EDS revealed the presence of variously shaped material and particles containing Si in bioptical samples and in eluates. Si containing contaminants were not demonstrated in eluates filtered in absence of the dialyser. This result suggests that leachable products can result from the dialyser and that such release can be an additional risk for uraemic patients.

Electron Probe Microanalysis↗
PubMed1987

Mineral particles in the lungs of subjects resident in the Rome area and not occupationally exposed to mineral dust.

We studied the inorganic particulate contained in the lung parenchyma of 10 subjects (5 males and 5 females) resident in an urban area and not occupationally exposed to dusts. A total of 17 mineral types were identified, along with 16 metal elements in the form of oxides and sulfides. Approximately 70% of the minerals were made up of phyllosilicates, in particular clay, mica, and talc; three metal elements, Fe, Al, and Ti, accounted for more than 75% of the recovered oxide particles. The mean concentration of the observed inorganic particles was approximately 1.8 X 10(5) pp/mg dry tissue. No significant differences were observed in terms of total particulate concentration in the various areas of the lungs and between the right and left lung. Instead we observed a larger concentration of fibrous particles in the upper lobes. The analysis of the data made it possible to determine the presence of a high degree of correlation between the concentrations of silicates and the concentrations of metal oxides and sulfides, implying the existence of a ubiquitous environmental source of these mineral particles. The frequent observation of tremolite fibers is remarkable. This finding, confirmed elsewhere, indicates that the magnitude of the sources of these fibers in the environment, constituted by contaminated talc dusts, has been underestimated until today.

Aged↗
PubMed1987

Entry pathway of vesicular stomatitis virus into different host cells.

A biochemical and morphological investigation of the mechanism of entry of vesicular stomatitis virus (VSV) into host cells of mammalian (HeLa), avian (CER), piscine (EPC) and arthropod (Aedes albopictus) origin, is described. VSV was capable of infecting all cell lines tested by a endosome- and/or a lysosome-dependent step since ammonium chloride and amantadine blocked the early stages of infection. Complement-dependent immune lysis of infected host cells provided evidence that in none of the four different cell types examined did insertion of VSV antigens occur from the outside to any great extent on the cell surface. When the entry process was studied by electron microscopy, virus particles were seen to be bound to the cell surface at 0 degrees C. After warming at 37 degrees C for homeothermic cells or at 26 degrees C for poikilothermic cells, virus was detected within coated pits and coated vesicles and, later, in lysosomes. VSV entry was seen to take place by endocytosis in all four cell lines, which were derived from phylogenetically unrelated species.

Aedes↗
PubMed1987

Cytotoxic necrotizing factor production by hemolytic strains of Escherichia coli causing extraintestinal infections.

Two hundred and nineteen strains of Escherichia coli from extraintestinal infections and feces of healthy subjects were examined for hemolysin (Hly) and cytotoxic necrotizing factor (CNF) production and for mannose-resistant hemagglutination. Of 105 strains from extraintestinal infections, 42 (40.0%) were positive for production of both Hly and CNF, and 21 (20.0%) were positive for Hly alone; on the contrary, only 1 Hly- and CNF-positive strain and 2 Hly-positive strains were found among 114 strains from normal stools. CNF production was not found to occur among the nonhemolytic strains, confirming the close association existing between these toxic factors. Hemolytic strains positive for CNF showed mannose-resistant hemagglutination less frequently than did Hly-positive, CNF-negative strains (25.6 versus 82.6%), suggesting the existence of two distinct classes among hemolytic strains of E. coli.

Cytotoxins↗