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Biomedical subjects

M Alessio

Publications and source records attributed to M Alessio.

46 records · Page 3Linked to original sources
PubMed1988

Pathogenesis of postantibiotic diarrhoea caused by Clostridium difficile: an in vitro study in the rabbit intestine.

To elucidate the pathophysiological changes leading to postantibiotic diarrhoea caused by Clostridium difficile and its cytotoxin, oral ampicillin was given to rabbits, and jejunal, ileal, and caecal segments of those that developed diarrhoea were investigated in vitro. The rabbits that, in response to treatment, harboured Clostridium difficile in their colonic lumen were studied, and the results expressed according to the presence or absence of Clostridium difficile and/or its cytotoxin. Thus, we refer to either CD+ or CD- segments. The influx of glucose, phenylalanine, glycylphenylalanine, and lysine across the brush border of jejunum and ileum of CD+ segments was severely impaired, while only slightly blunted in CD-. No significant change was detected in the influx of glutamic acid in the jejunum of all treated animals and in the CD- ilea. Morphologic damage in ileum and caecum of CD+ was also more evident than in CD-. Transepithelial ion transport across short circuited ileal mucosa (CD+ and CD-) revealed secretory changes in Cl net transport that were more marked in CD-. We conclude that: (1) Clostridium difficile may also colonise the upper intestinal tract, where it induces morphological and functional damage, severely impairing nutrient absorption; and (2) the ileum contributes to the diarrhoea caused by CD even when the micro-organism is confined to the more distal gut by showing moderate impairment of nutrient absorption and marked electrolyte secretion.

Ampicillin↗
PubMed1988

Alloantigen and microbial antigen-induced cellular immune responses: inhibitory effects of four anti-HLA class II monoclonal antibodies.

Four monoclonal antibodies (MAb's) directed against different epitopes of class II structures coded for by the human major histocompatibility complex (HLA), were studied to evaluate the relevance of these molecules on the control of different in vitro cell-mediated immune responses. Irrespective of the epitopes recognized, all MAb's tested exerted a powerful inhibitory effect on mixed lymphocyte cultures and on proliferation induced by microbial antigens. The generation of cytotoxic T lymphocytes and natural killer-like effectors also were inhibited by the addition of anti-HLA class II MAb in the cultures. The anti-HLA class II MAb provide a useful tool for the study of the in vitro immune response and eventually for therapeutic immunomodulation.

Antibodies, Monoclonal↗
PubMed1988

Recognition by monoclonal antibody CB02 of a surface molecule shared by B lymphocytes and a discrete large granular lymphocyte subset with cytotoxic activity.

Here we present the characterization of a new antigen called CB02 which is present on B cells and on a subset of CD16+ large granular lymphocytes. The pattern of reactivity of this molecule on normal cells, B cell lines, leukemic cells and tissue sections suggests that the CB02 molecule is expressed by B cells before isotype switch and is lost during terminal differentiation. Furthermore, the CB02+ population encompassed natural killer (NK) cells exerting significant cytotoxic activity: in fact, peripheral blood lymphocytes depleted of the CB02+ subset display a marked reduction in NK activity.

Animals↗
PubMed1987

Production of Escherichia coli STa-like heat-stable enterotoxin by Citrobacter freundii isolated from humans.

Citrobacter species are often present in the stools of children and are generally considered a normal component of the intestinal microflora. Previous reports suggested that they might act as enteric pathogens. Aiming at defining the role of Citrobacter species in inducing diarrhea, we looked for their presence in the stools of 328 children with diarrhea and in 108 controls. Citrobacter strains were isolated from 46 patients (14%) and 7 controls (6.5%) (P less than 0.05). All isolates were tested for heat-stable (ST) and heat-labile (LT) enterotoxin. No LT-producing organisms were found. Three C. freundii strains, all isolated from children with diarrhea, elaborated an enterotoxin detected by the suckling mouse assay. A crude extract was prepared by acetone precipitation and a sequential ultrafiltration technique. The enterotoxin was heat stable, and its estimated molecular weight was between 2,000 and 10,000. Citrobacter enterotoxin was soluble in methanol and stable at acid and neutral pHs but not above pH 8, and its activity was destroyed by treatment with 2-mercaptoethanol. Citrobacter enterotoxin was inactive in the 18-h rabbit ileal loop test. All these characteristics closely resemble STa produced by Escherichia coli. The time course of Citrobacter enterotoxin-induced intestinal secretion in suckling mice was similar to that of E. coli STa. The enterotoxin produced by C. freundii cross-reacted with monoclonal antibodies raised against E. coli STa. These results suggest that C. freundii is capable of inducing diarrhea through the production of an E. coli-like STa, and its presence in the stools of patients with diarrhea should be considered as that of a possible etiologic agent.

Bacterial Toxins↗
PubMed1986

Definition by CB12 monoclonal antibody of a differentiation marker specific for human monocytes and their bone marrow precursors.

The CB12 monoclonal antibody, which reacts with a molecule expressed on monocytes, was characterized using human embryonic material as immunizer. Analysis of the monoclonal antibody at the phenotypic, molecular, and functional levels indicates that its reactivity is restricted to circulating monocytes and their precursors in the bone marrow, whereas it is undetectable on tissue macrophages. CB12 displays a pattern of reactivity compatible with that of a marker of monocyte differentiation. Preliminary data indicate a possible receptor role for the CB12 molecule.

Antibodies, Monoclonal↗
PubMed1986

Detection of clostridial toxins in stools from children with diarrhoea.

A cell-culture assay was used to detect toxins directly in stools from sporadic cases of infantile diarrhoea. Cytotoxins were revealed in 11 out of 58 samples from children with diarrhoea, nine of whom had no common enteric pathogens in their stools. A preliminary characterisation of the cytotoxins was obtained by neutralisation tests with clostridial antitoxins.

Bacterial Proteins↗
PubMedDate not supplied

Generation and characterization of a murine monoclonal antibody specific for the human T1-CD5 molecule.

Murine monoclonal antibodies (MoAbs) have found widespread applications in the characterization of the molecular and functional features of lymphocyte differentiation antigens. The present paper summarizes the results of our work dealing with the production and selection of a murine MoAb recognizing a molecule expressed during the whole differentiative life of T lymphocytes. The MoAb CB01 resulted to be specific for an apparently unique epitope of the T-cell specific membrane glycoprotein T1-CD5.

Animals↗
PubMedDate not supplied

The Italian version of the Childhood Health Assessment Questionnaire (CHAQ) and the Child Health Questionnaire (CHQ).

We report herein the results of the cross-cultural adaptation and validation into the Italian language of the parent's version of two health related quality of life instruments. The Childhood Health Assessment Questionnaire (CHAQ) is a disease specific health instrument that measures functional ability in daily living activities in children with juvenile idiopathic arthritis (JIA). The Child Health Questionnaire (CHQ) is a generic health instrument designed to capture the physical and psychosocial well-being of children independently from the underlying disease. The Italian CHAQ was already published in the literature and was therefore revalidated while the Italian CHQ was fully cross culturally adapted with 3 forward and 3 backward translations, and than validated. A total of 1,192 subjects were enrolled: 404 patients with JIA (16% systemic onset, 31% polyarticular onset, 21% extended oligoarticular subtype, and 32% persistent oligoarticular subtype) and 788 healthy children. The CHAQ clinically discriminated between healthy subjects and JIA patients, with the systemic, polyarticular and extended oligoarticular subtypes having a higher degree of disability, pain, and a lower overall well-being when compared to their healthy peers. Also the CHQ clinically discriminated between healthy subjects and JIA patients, with the systemic onset, polyarticular onset and extended oligoarticular subtypes having a lower physical and psychosocial well-being when compared to their healthy peers. In conclusion the Italian version of the CHAQ-CHQ are reliable, and valid tools for the functional, physical and psychosocial assessment of children with JIA.

Adolescent↗
PubMedDate not supplied

Oral versus intramuscular methotrexate in juvenile chronic arthritis. Italian Pediatric Rheumatology Study Group.

OBJECTIVE: To compare the efficacy and safety of methotrexate (MTX) after oral and intramuscular administration in children with juvenile chronic arthritis (JCA). METHODS: Pediatric rheumatology centers in Italy participated in this short-term, prospective, open trial. Each investigator was allowed to choose the oral or intramuscular route of administration according to his personal preference in everyday clinical practice. Patients enrolled by each center were given MTX through the same method of administration. All patients received 10 mg/m2 of MTX each week for six months. RESULTS: A total of 257 patients with JCA (127 treated orally and 130 intramuscularly) were enrolled in the trial by 11 Italian centers. The response rate after 6 months of MTX therapy was 58% in the oral and 61% in the intramuscular cohort. The frequency of adverse side effects did not differ significantly between the two treatment groups. CONCLUSION: The results of this study suggest that MTX at the conventional dose regimen is equally effective and has a similar safety profile in children with JCA when administered orally or by intramuscular injections.

Administration, Oral↗