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Biomedical subjects

F M Ruggeri

Publications and source records attributed to F M Ruggeri.

31 records · Page 2Linked to original sources
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

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↗
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↗
PubMed1985

Toxin production and haemagglutination in strains of Escherichia coli from diarrhoea in Brescia, Italy.

Two hundred and ninety-nine different strains of Escherichia coli, isolated from 172 patients with diarrhoea and 113 healthy subjects, were examined for enterotoxin, cytotoxin and haemolysin (Hly) production and for mannose-resistant haemagglutination (MRHA) and invasive properties. Three strains proved enterotoxigenic, none enteroinvasive; cytotoxin and Hly production was shown in 25 strains from patients and in 3 from controls. Ten strains produced the cytotoxic necrotizing factor (CNF), 6 released other factors which kill cell cultures. Hly production was shown in 21 strains, 9 of which were also positive for CNF. MRHA was detected in 26% of strains from diarrhoea compared with 14% of strains from healthy people. A strong association between toxin production and MRHA was demonstrated. Serotyping results showed that the strains exhibiting virulence traits mostly belonged to serogroups commonly involved in extra-intestinal infections. The possible role of strains of E. coli showing one or more virulence factors as opportunistic pathogens in diarrhoeal diseases is discussed.

Adhesiveness↗
PubMed1985

Acute childhood diarrhoea in Naples: an aetiologic study.

A potential aetiologic agent was detected in the stools of 56% of 118 children hospitalized in Naples for acute diarrhoea. Rotavirus and Salmonella were the agents most commonly associated with disease, accounting for 23 and 17 percent of cases, respectively. Campylobacter jejuni, enterotoxigenic Escherichia coli, Yersinia and Shigella were less frequently isolated (total, 11% of cases). These findings fit well with the epidemiological picture described for other developed countries, except for the isolation rate of Salmonella which widely exceeds that reported in other investigations. Cytotoxic strains of E. coli and other Gram-negative bacilli were identified in the stools of 18 children; the possible pathogenic role of these strains is unknown and needs further investigation.

Acute Disease↗
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

Enteric infections, cow's milk intolerance and parenteral infections in 118 consecutive cases of acute diarrhoea in children.

One hundred and eighteen consecutive cases of childhood acute diarrhoea (mean age: 10.5 months) were studied after admission to our Pediatric Unit in Naples over a 13-month period. A diagnosis was established in 92 patients (78%): 55% of patients were found to have an infectious enteritis (among them, 5 had ETEC infections and 1 had an ST-producing Klebsiella infection), 12% a parenteral infection, 11% cow's milk intolerance. The occurrence of gross blood (P less than 0.01), leukocytes, and reducing substances in the stools was more commonly associated with infectious enteritis than with diarrhoea due to all other causes. In 14 patients (8 of whom were malnourished), diarrhoea ran a prolonged course. In all, the eventual outcome was favourable. Our findings, while confirming that infectious enteritides account for most of acute diarrhoeas in children, stress the importance of parenteral infections and cow's milk intolerance in this condition. Also, the need for an accurate search for enterotoxigenicity of enterobacteria before ruling out their pathogenetic role is stressed.

Bacterial Infections↗
PubMed1984

Measles epidemiology in Italy.

In preparation for a mass vaccination programme, the immune status with regard to measles was determined in over 8300 unvaccinated children aged 0-13 years, residing in eight Italian cities with different socioeconomic situations and geographical locations. The age corresponding to the 50% prevalence of immunes appeared to be intermediate (2.9-5.5 years) between that reported for industrialized (6-7 years) and developing countries (1-2 years). The 50% prevalence of natural immunity was reached at an earlier age in southern cities in which poorer socioeconomic and hygienic conditions prevailed; the earlier occurrence of measles in these areas was confirmed by a more detailed serological study of children in the first 24 months of life. For children aged 2-13 years, serological results showed that the history of measles reported by parents on questionnaires gave high positive predictive values (over 85%). Our seroepidemiological study shows that, on the basis of the ages of 25 and 75% prevalence of immunes, the target population for a mass immunization programme in Italy can be assumed to be aged from 12 months to 7 years. However, special attention should be given to the poorest areas, especially in southern Italy, where measles occurs earlier and can be particularly severe.

Adolescent↗
PubMed1984

Serum antibodies to poliomyelitis in Italy.

A seroepidemiological survey was conducted to assess the effectiveness of the Italian nationwide immunization programme against poliomyelitis. Over 3800 serum samples were collected from persons, aged between 6 months and 79 years and residing in urban and rural areas with different socioeconomic conditions and geographic locations.A very high level of protection was found in the target population, confirming the almost 100% history of complete immunization. Almost all subjects over 30 years of age were found to have poliovirus antibodies, although they had never been vaccinated. In Naples, a higher proportion of subjects susceptible to all 3 types of virus was found in the age group 6-23 months, suggesting a delay in the administration of vaccine. This was confirmed by the analysis of the immunization history. No difference was observed between urban and rural areas, in either serological results or history of immunization.The results confirmed the higher immunogenicity of poliovirus type 2 with respect to the other two types, the effectiveness of the vaccine, and, finally, the efficiency of the operational procedures adopted for its administration.

Adolescent↗
PubMed1983

Partial purification and characterization of an escherichia coli toxic factor that induces morphological cell alterations.

A factor produced by several strains of Escherichia coli isolated from enteritis-affected children has been shown to produce both a necrotizing effect on rabbit skin and striking morphological alterations on CHO, Vero, and HeLa cells. The same strains were found to have hemolytic activity on sheep erythrocytes. The toxic, cell-altering factor was demonstrated to be different from both heat-labile and heat-stable enterotoxins and from Vero toxin. The main effect induced by the isolated factor on cultured cells was the formation of large multinucleated cells. The partial purification achieved suggests that the same factor (most likely a protein with a molecular weight of 70,000 to 80,000) is responsible for toxic and cell-altering activities, whereas a different molecular species is responsible for hemolytic activity.

Animals↗