PubMed Health⌕ Search

Biomedical subjects

L Fattorini

Publications and source records attributed to L Fattorini.

At least 55 records · Page 3Linked to original sources
PubMed1994

Induction of IL-1 beta, IL-6, TNF-alpha, GM-CSF and G-CSF in human macrophages by smooth transparent and smooth opaque colonial variants of Mycobacterium avium.

Both smooth transparent (SmT) and smooth domed-opaque (SmD) colonial variants were obtained from a strain of Mycobacterium avium isolated from a patient with AIDS. The two variants showed similar biochemical characteristics but SmT bacteria proliferated better than SmD bacteria inside human macrophages and were much less capable than the SmD variant of inducing the release of IL-1 beta, IL-6, TNF-alpha, GM-CSF and G-CSF, after incubation for either 3 or 6 days. As cytokines are important extracellular signals for immune cells, the lack of induction observed in SmT-infected macrophages may be one of the pathogenic mechanisms of M. avium.

AIDS-Related Opportunistic Infections↗
PubMed1994

Transcription and expression analysis, using lacZ and phoA gene fusions, of Mycobacterium fortuitum beta-lactamase genes cloned from a natural isolate and a high-level beta-lactamase producer.

The gene encoding a class A beta-lactamase was cloned from a natural isolate of Mycobacterium fortuitum (blaF) and from a high-level amoxicillin-resistant mutant that produces large amounts of beta-lactamase (blaF*). The nucleotide sequences of the two genes differ at 11 positions, including two in the region upstream from the coding sequence. Gene fusions to Escherichia coli lacZ and transcription and expression analysis of the cloned genes in Mycobacterium smegmatis indicated that high-level production of the beta-lactamase in the mutant is mainly or wholly due to a single base pair difference in the promoter. These analyses also showed that transcription and translation start at the same position. A comparison of the amino acid sequence of BlaF, as predicted from the nucleotide sequence, with the determined N-terminal amino acid sequence indicated the presence of a typical signal peptide. The fusion of blaF (or blaF*) to the E. coli gene phoA resulted in the production of BlaF-PhoA hybrid proteins that had alkaline phosphatase activity. These results demonstrate that phoA can be used as a reporter gene for studying protein export in mycobacteria.

Alkaline Phosphatase↗
PubMed1994

Use of the chromosomal class A beta-lactamase of Mycobacterium fortuitum D316 to study potentially poor substrates and inhibitory beta-lactam compounds.

Sixteen different compounds usually considered beta-lactamase stable or representing potential beta-lactam inhibitors and inactivators were tested against the beta-lactamase produced by Mycobacterium fortuitum. The compounds exhibiting the most interesting properties were BRL42715, which was by far the best inactivator, and CGP31608 and ceftazidime, which were not recognized by the enzyme. These compounds thus exhibited adequate properties for fighting mycobacterial infections. Although cloxacillin, dicloxacillin, cefoxitin, and CP65207-2 exhibited poor inhibitory efficiency against the enzyme, they were also rather poor substrates and might be considered potential antimycobacterial agents. By contrast, CGP31523A and ceftamet were good substrates.

Anti-Bacterial Agents↗
PubMed1994

ARX filtering of single-sweep movement-related brain macropotentials in mono- and multi-channel recordings.

A technique of stochastic parametric identification and filtering is applied to the analysis of single-sweep event-related potentials. This procedure, called AutoRegressive with n eXogenous inputs (ARXn), models the recorded signal as the sum of n+1 signals: the background EEG activity, modeled as an autoregressive process driven by white noise, and n signals, one of which represents a filtered version of a reference signal carrying the average information contained in each sweep. The other (n-1) signals could represent various sources of noise (i.e., artifacts, EOG, etc.). An evaluation of the effects of both artifact suppression and accurate selection of the average signal on mono- or multi-channel scalp recordings is presented.

Brain Mapping↗
PubMed1993

Systemic sclerosis following anti-androgenic treatment for prostatic adenocarcinoma.

We describe a male patient who developed systemic sclerosis following orchiectomy, radiotherapy and anti-androgenic treatment for prostatic adenocarcinoma. This case appears interesting as it further supports the possibility of a relationship between neoplasia and systemic sclerosis. The concurrence of scleroderma and iatrogenic hypoandrogenism suggests that hormonal influences may also play a role in the pathogenesis of this connective tissue disorder.

Adenocarcinoma↗
PubMed1992

Resistance to beta-lactams in Mycobacterium fortuitum.

It is widely assumed that the high level of intrinsic resistance to beta-lactam antibiotics exhibited by mycobacteria results from the combination of factors including permeability to the drugs, beta-lactamase production, and affinity for penicillin-binding proteins (PBPs). We conducted an evaluation of the second and third factors by isolating nitrosoguanidine-induced mutants from the beta-lactamase-producing strain Mycobacterium fortuitum ATCC 19542 that displayed either elevated or reduced resistance to various beta-lactam antibiotics. The mutants studied included D1 (a beta-lactamase producer with high penicillin resistance), gamma 27 (a low-level beta-lactamase producer with low penicillin resistance), and D316 (a high-level beta-lactamase producer with high penicillin resistance). In all strains examined, four major PBPs, named 1, 2a, 2b, and 3, with apparent molecular weights of 102,000, 90,000, 87,000, and 50,000, respectively, were found. The MICs of various beta-lactams toward ATCC 19542 and its mutants were considered in the context of beta-lactamase production, the quantity of PBPs synthesized, and their affinities for beta-lactam antibiotics. The data obtained show that beta-lactamase production is likely to be an important factor in the expression of resistance by clinical isolates and that PBP alterations can contribute to resistance at least in laboratory-derived mutants.

Anti-Bacterial Agents↗
PubMed1992

Activity of antimicrobial agents against Mycobacterium avium-intracellulare complex (MAC) strains isolated in Italy from AIDS-patients.

Twenty-five strains of Mycobacterium avium-intracellulare (MAC) isolated from acquired immunodeficiency syndrome (AIDS) patients in three medical centres in Italy have been studied. Serotyping performed on eighteen strains showed various serovars within either M. avium or M. intracellulare serotypes and with serovars 1 and 21 being the most prevalent (four strains for each serovar). Among fourteen drugs used for testing the antibiotic sensitivity, rifapentine, rifabutin and clofazimine showed to have the best in vitro activity. In an ex vivo model of infection using peritoneal resting macrophages from the C57BL/6 mouse, the intracellular viability of a strain of M. avium (strain 489, serovar 3) was reduced by clofazimine, amikacin, ciprofloxacin, rifabutin and clarithromycin (99, 98, 93, 89 and 69%, respectively), thus indicating for clofazimine a good correlation between in vitro and ex vivo activity.

Acquired Immunodeficiency Syndrome↗
PubMed1991

[Clinical report of a case of CREST syndrome].

A case of CREST syndrome presenting with marked diffuse calcinosis and prevailing joint involvement is presented by the authors. Diffractometry revealed the presence of calcified hydroxy-apatite crystals within subcutaneous nodules. Scleroderma-like microcirculatory changes with blood flow alterations typical of Raynaud's syndrome were present on capillaroscopy. The authors feel the case to be of interest not only in view of the rare occurrence of the condition but also of the particular extent and severity of the signs and symptoms presented by this patient.

Female↗
PubMed1991

In vitro activity of clarithromycin alone or in combination with other antimicrobial agents against Mycobacterium avium-intracellulare. Complex strains isolated from AIDS patients.

The activity of clarithromycin and five other antimicrobial agents, namely amikacin, rifampicin, rifabutin, clofazimine and ciprofloxacin, was assessed both by an agar dilution and a radiometric method in broth on 11 Mycobacterium avium-intracellulare complex (MAC) strains, recently isolated from AIDS patients. Minimum inhibitory concentrations (MICs) radiometrically determined were, in general, several times lower than MICs assessed in agar, probably because of a partial degradation of antimicrobials during the long incubation period needed for tests in solid medium. When tested in broth, rifabutin and clofazimine showed very low MICs 90 (0.24 and 0.78 microgram/ml, respectively). Ciprofloxacin and clarithromycin also had MICs90 in the range of peak serum levels (1.93 and 3.76 micrograms/ml, respectively). Moreover, all these antimicrobials are known to concentrate several times in macrophages. MICs90 were higher for amikacin (11 micrograms/ml) and for rifampicin (8 micrograms/ml). When clarithromycin was tested against three MAC strains in combination with another drug, it showed a synergistic effect only when combined with rifampicin. Some synergistic effect was observed also when combining clarithromycin with rifampicin and amikacin, whereas in combination with rifabutin and clofazimine there was only an additive effect.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Beta-lactamase of Mycobacterium fortuitum: kinetics of production and relationship with resistance to beta-lactam antibiotics.

The kinetics of both intracellular and extracellular beta-lactamase production and the relationship between extracellular enzyme and in vitro susceptibility of Mycobacterium fortuitum to beta-lactam antibiotics have been studied. To this end we used a panel of stable nitrosoguanidine-induced mutants of M. fortuitum derived from the parental strain ATCC 19542 and differing in beta-lactamase production from 0.0001 to 278 U/liter in Mueller-Hinton broth. For overproducers of beta-lactamase (mutants A188, B180, C207, D316, and E31), MICs of benzylpenicillin, amoxicillin, ampicillin, and cephaloridine progressively increased with the amount of enzyme released into the medium, whereas MICs of imipenem and cefoxitin did not. The resistance of the mutants to amoxicillin was reduced up to 32-fold by clavulanic acid, whereas that to ampicillin was reduced 8-fold by sulbactam. These data suggest that the enzyme participated in the mechanisms of resistance to the beta-lactam antibiotics. However, for a mutant of M. fortuitum (gamma 27) with virtually nonexistent beta-lactamase production, the antibiotics still had relatively high MICs (for instance, benzylpenicillin and cephaloridine had MICs of 64 and 32 micrograms/ml, respectively). This suggests that, aside from beta-lactamase production, other mechanisms such as cell wall permeability and/or affinity for penicillin-binding proteins could coexist in M. fortuitum and explain its natural resistance to beta-lactam antibiotics.

Anti-Bacterial Agents↗
PubMed1991

Clinical efficacy and tolerance of galactosoaminoglucuronoglycan sulfate in the treatment of osteoarthritis.

An open design has been carried out by the authors comparing the efficacy and the tolerance of galactosoaminoglucuronoglycan sulfates (GAGs) with those of ibuprofen lysine in patients affected by osteoarthritis (OA). The experimental group included forty patients of both sexes, aged from 35 to 67 years, with diffuse OA. Ten patients were treated with GAGs administered orally (600-1200 mg/die) and ten patients with GAGs administered intramuscularly (50-100 mg/die); likewise for the ibuprofen therapy two subgroups were formed, such that ten patients were given the drug orally (1500-2500 mg/die) and ten patients had intramuscular therapy (400-800 mg/die). The treatment lasted 40 days. The parameters considered were: pain at rest, pain on pressure, pain on active movement and pain on passive movement. Tolerance was considered by carrying out some routinary laboratory tests and a careful clinical and anamnestic examination. At the end of the study, an improvement in all the clinical variables considered was found in both groups of patients, with no significant differences between the oral and the intramuscular administrations. With regard to tolerance, it must be noted that 10% of the patients in each of the two considered groups patients suffered from gastro-intestinal diseases (pain, nausea, pyrosis). The results achieved, therefore, confirm the efficacy and above all the good tolerance of GAGs in the treatment of OA, characteristics of particular importance for a drug designed for the therapy of a chronic pathology such as OA.

Adult↗
PubMed1990

Characterization of a beta-lactamase produced in Mycobacterium fortuitum D316.

A beta-lactamase from Mycobacterium fortuitum D316 was purified and some physico-chemical properties and substrate profile determined. On the basis of its N-terminal sequence and of its sensitivity to beta-iodopenicillanate inactivation, the enzyme appeared to be a class A beta-lactamase, but its substrate profile was quite unexpected, since nine cephalosporins were among the eleven best substrates. The enzyme also hydrolysed ureidopenicillins and some so-called 'beta-lactamase-stable' cephalosporins.

Amino Acid Sequence↗
PubMed1989

Inhibitors and inactivators of beta-lactamase from Mycobacterium fortuitum.

The inhibiting or inactivating effects of some beta-lactam antibiotics on beta-lactamase from Mycobacterium fortuitum were studied. Among all substrates tested, clavulanic acid and sulbactam were the strongest competitive inhibitors of the enzyme although the latter was slightly hydrolyzed. Imipenem and cefoxitin scarcely inhibited the beta-lactamase yet expressed good activity against the microorganism in vitro, suggesting that the effectiveness of these drugs on M. fortuitum might be due to high permeation through the cell wall. All the isoxazolylpenicillins tested and methicillin inactivated the enzyme of M. fortuitum by a first rapid phase of acylation followed by a steady-state process of enzyme reactivation (deacylation). Clavulanic acid and sulbactam showed Ki values for the enzyme inactivation closely corresponding to hematic concentrations achievable in vivo during antibiotic treatment.

Anti-Bacterial Agents↗
PubMed1989

Beta-lactamase production and biological characteristics in nitrosoguanidine induced Mycobacterium fortuitum mutants.

In order to elucidate the role of beta-lactamase in the resistance of M. fortuitum to beta-lactams, M. fortuitum ATCC 19542 and three mutants, strains D 316, D 319 and D 170 obtained from it by nitrosoguanidine treatment, were studied. Furthermore the kinetics of the beta-lactamase production during the bacterial growth and many biochemical and enzymatic characteristics of parent and mutant strains were investigated. Amoxicillin MICs well correlated with the beta-lactamase production in the high producer strains D 316 and D 319; on the contrary in strain D 170 a high MIC was joined with a moderate production of the enzyme showing that not only beta-lactamase but also other mechanisms can be effective in the resistance of M. fortuitum to beta-lactams. Clavulanic acid, an inhibitor of beta-lactamase, reduced MICs to amoxicillin in high and in low producer strains. The production of extracellular beta-lactamase occurred in a M. fortuitum mutant strain mainly during the stationary phase, indicating that a cell wall damage or initial autolysis could be responsible for the release of enzyme. Enzymatic and biochemical characteristics were not affected by nitrosoguanidine treatment except for nitrate test which showed only a weak positivity in high producer strains.

Anti-Bacterial Agents↗
PubMed1988

Colchicine treatment in a case of pachydermoperiostosis with acroosteolysis.

We report a case of pachydermoperiostosis with arthralgia, acroosteolysis, and recurrent staphylococcal folliculitis of the face, treated with colchicine (0.5 mg once daily for the 1st week and 0.5 mg twice daily for the next 3 weeks). The evaluation of arthralgia, hyponchial angle, folliculitis, and pachyderma, performed at basal time and once weekly, showed improvement of symptoms and signs after 7-15 days of treatment. Neutrophilic chemotaxis, evaluated before starting the treatment and after 15 and 30 days of therapy, showed a progressive decrease of the initial very high index. Colchicine provided a beneficial therapeutic response in both inhibiting increased chemotactic activity and in reducing tissular oedema in our patient.

Adult↗
PubMed1988

Pachydermoperiostosis and acro-osteolysis.

The authors present a case of pachydermoperiostosis (digital hippocratism, periostosis, pachydermia) associated with acro-osteolysis. This is the first association of this type described in Italy, and it is only recently that foreign authors have reported the presence of acro-osteolysis in patients affected with pachydermoperiostosis. The results obtained from studies of the micro and macro circulation in pachydermoperiostosis are reported.

Adult↗