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A Caprioli

Publications and source records attributed to A Caprioli.

At least 73 records · Page 4Linked to original sources
PubMed1994

Multivariate analysis of behavioral aging highlights some unexpected features of complex systems organization.

Ten different behavioral tests were performed on a population of young (n = 20) and aged (n = 20) Fischer 344 rats. The relationship structure among these tests was studied by principal component analysis applied both to the entire data set and separately to the two age groups. This analysis proved very useful in highlighting a global index of the rat "behavioral" age based on the entire test set. The analysis effected separately on the two age groups evidenced qualitative differences between them that were linked to the different meaning the same test would assume in rats of different ages. From an overall methodological viewpoint, this work indicates that the correlations among behavioral parameters appear to depend on the observational scale and that the spin-glass model represents an appropriate metaphor to approach the study of the correlations in biological systems.

Aging↗
PubMed1994

A community outbreak of haemolytic-uraemic syndrome in children occurring in a large area of northern Italy over a period of several months.

From March to October 1993, 15 cases of haemolytic-uraemic syndrome (HUS) in children were detected in a large area of northern Italy, where only 8 cases had occurred in the previous 5 years. Analysis of stool and serum specimens obtained from 14 cases showed evidence of Verotoxin-producing Escherichia coli (VTEC) infection in 13. Serum antibodies to the E. coli O157 lipopolysaccharide (LPS) were found in 8 patients and to the O111 LPS in 2. An O86 VTEC was isolated from another patient. Fourteen children needed dialysis, and 1 died. No obvious epidemiologic link was observed among cases, most of whom lived in small townships. A case-control study did not show an association between HUS and food or exposure to cattle, but suggested an association with contact with chicken coops (OR = 6.5, 95% C.I. 1.2-34.9). However, VTEC were not isolated from stool samples obtained from the chicken coops involved. The risk factors for VTEC infection related to living in rural settlements, including the exposure to live poultry, should be considered in outbreak investigations.

Animals↗
PubMed1994

Community-wide outbreak of hemolytic-uremic syndrome associated with non-O157 verocytotoxin-producing Escherichia coli.

From 20 April through 13 May 1992, 9 children were hospitalized with hemolytic-uremic syndrome in Lombardia, Italy, where only 14 cases of this syndrome had occurred in the preceding 4 years. Cases were scattered in a large area encompassing five provinces, and the source of the outbreak was not identified. Eight patients needed dialysis, and there was 1 death. Seven of the 9 cases were examined for evidence of infection by Vero cytotoxin (VT)-producing Escherichia coli (VTEC). Six children had serum antibodies to the lipopolysaccharide of E. coli O111, and a VT-producing E. coli O111:NM was isolated from stool in 1 case. This is the first outbreak of VTEC infection recognized in Italy and the first associated with an E. coli serotype other than O157:H7.

Antibodies, Bacterial↗
PubMed1994

Variants of Shiga-like toxin II constitute a major toxin component in Escherichia coli O157 strains from patients with haemolytic uraemic syndrome.

The prevalence and genotype of Shiga-like toxins (SLTs) in Escherichia coli (O)157 strains from patients in Germany with haemolytic uraemic syndrome (HUS) were investigated. This was done by PCR amplification of the B-subunit genes with two primer pairs--one complementary to slt-IB, and the other homologous to both slt-IIB and slt-IIvB sequences. To distinguish between slt-II and slt-IIv, the amplified DNA was digested with restriction endonucleases HaeIII and FokI. Of the 38 strains examined, 17 harboured sequences for slt-IIv; four contained only slt-IIv, three carried both slt-IIv and slt-I, and 10 strains had slt-IIv and slt-II. A further three genotypes (slt-I, slt-II, slt-I/slt-II) were found in the remaining 21 strains resulting in a total of six slt genotypes. To determine whether the slt genes were expressed, and whether genotypes correlated with phenotypes, all strains were subjected to cytotoxicity assays and colony ELISA. All 38 strains displayed cytotoxic activity to Vero cells in similar quantities. The SLT-I-specific monoclonal antibody (MAb)13C4 reacted with all 10 strains in which slt-I sequences were identified. Colony blot ELISA with the SLT-II specific MAb11E10 detected 27 of 28 strains with slt-II sequences, but did not react with any of the seven strains that carried slt-IIv, or slt-I and slt-IIv. The high SLT variability shown here has diagnostic implications and may well have consequences for the host response in infections associated with these pathogens.

Animals↗
PubMed1994

Detection of enteroadherent Escherichia coli associated with diarrhoea in Italy.

One hundred and sixty-eight isolates of Escherichia coli obtained in Italy from 112 children with diarrhoea and 56 age-matched controls were examined by the HEp-2 cell adhesion assay. Sixteen strains showed localised adherence (LA), 29 showed diffuse adherence (DA) and eight strains showed aggregative adherence (AA). No adhesion pattern was significantly associated with disease. Strains that showed LA or AA were further characterised by serotyping, fluorescent actin staining (FAS) test and hybridisation with the EPEC adherence factor (EAF), E. coli attaching and effacing (eae) and enteroaggregative (EAgg) DNA probes. Strains that showed poor LA were FAS-negative, did not belong to EPEC serotypes and did not hybridise with EPEC probes. Conversely, the two strains that showed a good LA pattern belonged to serotype O128:H2, were FAS positive and hybridised with the eae probe. No isolate hybridised with the EAF probe. Only three of the eight strains with the AA pattern hybridised with the EAgg probe. Probe positivity correlated with the ability to produce clumps at the surface of the liquid culture and to agglutinate rat erythrocytes. In two of these EAgg probe-positive strains, electronmicroscopy revealed the presence of fibrillar bundles which seem to mediate bacterial aggregation.

Bacterial Adhesion↗
PubMed1993

Characterization of apo(a) polymorphism by a modified immunoblotting technique in an Italian population sample.

Apo(a), the specific lipoprotein(a) (Lp(a)) apolipoprotein, is characterized by different isoforms (from 6 to 11 on SDS-PAGE) encoded by a system of autosomal codominant alleles. Electrophoresis on agarose gel displays a better resolving power than SDS-PAGE (a larger number of apo(a) isoforms is detected). The aim of this work was to set up a simple technique that uses a capillary blotting apparatus and a polyvinylidene difluoride membrane for protein transfer. We tested an Italian population sample of 202 healthy subjects (123 men and 79 women) and we detected 22 apo(a) isoforms varying from 280 to 775 kDa. In our sample, 135 subjects (66.5%) had a single-band phenotype, 64 (31.7%) had a double-band phenotype and 3 subjects (1.5%) had no detectable bands ('null' phenotype). This simple and reproducible technique could be applied in the genetic screening of apo(a) polymorphisms and for clinical investigations of the risk of developing cardiovascular diseases.

Adult↗
PubMed1993

Isolation and nucleotide sequence of the gene encoding cytotoxic necrotizing factor 1 of Escherichia coli.

Cytotoxic necrotizing factors (CNFs) are dermonecrotic protein toxins produced by human and animal clinical isolates of Escherichia coli. In this study, the CNF1 determinant was isolated and sequenced, showing that expression of biologically active toxin is governed by a unique open reading frame encoding a protein of 1,014 amino acids with a predicted molecular mass of 113.7 kDa. Nucleotide and protein data base searches showed significant homology between CNF1 and the dermonecrotic toxin of Pasteurella multocida. In particular, the two toxins were found to share a hydrophobic region of about 220 amino acids which is a potential membrane-spanning domain.

Amino Acid Sequence↗
PubMed1992

Spatial memory in aged rats: population heterogeneity and effect of levocarnitine acetyl.

The existence in a population of aging rats of classes that display a different performance in the Morris water-maze test was investigated by cluster analysis procedure. These classes identified at 18 months of age showed a different response to levocarnitine acetyl and had a different behavioral profile when tested at 25 months of age. These findings demonstrate the need for an alternative interpretation of variability in animal populations as measured by the standard statistical analyses. The data analysis strategy we propose here will allow for the use of variability as a useful source of information.

Acetylcarnitine↗
PubMed1992

Impaired detection of faecal verocytotoxin in the presence of Clostridium difficile cytotoxin in patients with haemolytic uraemic syndrome.

Three cases of haemolytic uraemic syndrome associated with infection with verocytotoxin producing Escherichia coli are described. The concomitant presence of Clostridium difficile cytotoxin in the patients' stool impaired the detection of free faecal verocytotoxin. Stool specimens containing Clostridium difficile cytotoxin should thus be considered negative for verocytotoxin only after neutralisation of the Clostridium difficile cytotoxin with antitoxin.

Animals↗
PubMed1992

Active avoidance learning in old rats chronically treated with levocarnitine acetyl.

The aging laboratory animal is recognized as a suitable experimental model for the investigation on drugs potentially able to retard the age-dependent decline in cognitive functions. There is robust evidence that levocarnitine acetyl (ALCAR), the acetyl derivative of carnitine, when administered chronically, prevents some age-related deficits of the central nervous system, mainly at the hippocampal level. On the basis of this evidence and because learning of active avoidance was demonstrated to become impaired with age, we decided to investigate the effect of ALCAR in rats. For statistical evaluation of results, the Cluster Analysis technique was chosen. This procedure pointed out the great heterogeneity of the old population and allowed the classification of the animals into homogeneous groups according to their response pattern. The effect of ALCAR was evident in the higher number of treated old animals yielding escape responses, indicating that ALCAR can preserve, at least partially, learning and memory from the natural decay occurring with age.

Acetylcarnitine↗
PubMed1992

Hemolytic-uremic syndrome and Vero cytotoxin-producing Escherichia coli infection in Italy. The HUS Italian Study Group.

In a 3-year prospective study, 49 Italian children with the hemolytic-uremic syndrome (HUS) were examined for evidence of infection with Vero cytotoxin-producing Escherichia coli (VTEC). Diagnosis of infection was established in 37 patients (75.5%) by the combined use of stool examination for VTEC and for free fecal neutralizable Vero cytotoxin and serum analysis for antibodies to the Vero toxins and the lipopolysaccharides (LPS) of three major VTEC serogroups (O157, O26, O111). Anti-LPS antibodies were detected in sera from 30 patients: 25 had antibody to O157 LPS, 4 to O26, and 1 to O111. In as many as 27 patients (55.1%), diagnosis of infection relied only on serologic findings, and the presence of antibody to LPS was the sole evidence of VTEC infection in 20 patients (40.8%). The use of LPS from different E. coli serogroups provided evidence that in Italy O157 strains are the most prevalent VTEC involved in HUS.

Adolescent↗
PubMed1992

Gene block encoding production of cytotoxic necrotizing factor 1 and hemolysin in Escherichia coli isolates from extraintestinal infections.

Cytotoxic necrotizing factors (CNFs) are Escherichia coli protein toxins causing cell multinucleation and enlargement in tissue cultures and necrosis in rabbit skin. In E. coli isolates causing urinary tract infections in humans, the production of CNF1 is closely associated with hemolysin production. In this study, we obtained data suggesting that this phenotypic association is due to the genetic linkage of the determinants of the two toxins on the chromosome of uropathogenic E. coli. The genes encoding hemolysin and CNF1 were shown to be closely linked in a 37-kb cloned DNA fragment from an E. coli urinary tract isolate of serotype O4:K12:H5 (E-B35). A DNA region encoding CNF1 production but not hemolysin production was further subcloned as a 12-kb SalI-EcoRI fragment and used as a CNF1-specific gene probe. DNA hybridization experiments indicated that the CNF1 and hemolysin determinants were closely linked on the chromosomes of isolate E-B35 and six additional extraintestinal isolates belonging to serogroups O2, O4, O6, O22, O75, and O85.

Bacterial Toxins↗
PubMed1991

Antimicrobial resistance and production of toxins in Escherichia coli strains from wild ruminants and the alpine marmot.

Escherichia coli strains isolated from 81 fecal samples from red deer (Cervus elaphus), roe deer (Capreoulus capreoulus), chamois (Rupicapra rupicapra) and alpine marmot (Marmota marmota) living in the Stelvio National Park, Italy, were examined for antimicrobial resistance and production of toxic factors. Direct plating of specimens on media containing antimicrobial drugs allowed us to isolate resistant strains of E. coli from 10 of 59 (17%) specimens examined by this technique. Nine of 31 specimens from red deer (29%) contained resistant strains. Different animals were likely colonized by the same resistant strain of E. coli. Conjugative R plasmids were found in four strains isolated from the marmot, roe deer and chamois. A strain from red deer produced heat-stable enterotoxin and another strain produced both hemolysin and cytotoxic necrotizing factor. A marmot isolate produced hemolysin alone. No strains were found to produce heat-labile enterotoxin or verotoxins.

Animals↗