Biomedical subjects

L Drago

Publications and source records attributed to L Drago.

At least 37 records · Page 2Linked to original sources

PubMed2000

Candida albicans cellular internalization: a new pathogenic factor?

The preliminary results of a study to show the possibility that Candida albicans can internalize into epithelial cells are reported. The study was performed on buccal, vaginal and HeLa cells. Buccal and vaginal cells, at a concentration of 5 x 10(4) cells/ml and HeLa monolayers were incubated for 2, 3 and 4 h with 10(5) colony forming units of a Candida albicans isolate. After incubation, non-internalised yeasts were eliminated and samples were processed for examination by Scanning Electron Microscopy. Results suggest that receptor-mediated endocytosis could be involved in the pathogenesis of recurrent oral and vaginal infections. This phenomenon could represent an interesting experimental model to testing drug interference in the development of therapeutic strategies against C. albicans infections.

Candida albicans↗

PubMed2000

Serum and lung levels of thiamphenicol after administration of its glycinate N-acetylcysteinate ester in experimentally infected guinea pigs.

Thiamphenicol is an analogue of chloramphenicol and is characterised by a broad spectrum of action. In this study, serum and lung levels of thiamphenicol (TAP) were studied in infected guinea pigs after the administration of thiamphenicol glycinate N-acetylcysteinate (TGA). Animals received a single dose of TGA (15 mg/kg, subcutaneously) immediately after intra-tracheal infection with Haemophilus influenzae (about 10(7) CFU/animal). Serum and lung concentrations of TAP were determined at 0, 1, 3, 6, 12 and 24 h after drug administration by means of HPLC. TAP serum levels were elevated at 1 h and remained detectable for 24 h after drug administration. Tissue lung levels were comparable to peak serum concentrations but remained higher and decreased more slowly than serum concentrations.

Acetylcysteine↗

PubMed2000

Evaluation of the abbott LCx HIV-1 RNA quantitative, a new assay for quantitative determination of human immunodeficiency virus type 1 RNA.

A new quantitative reverse transcription (RT)-PCR assay for human immunodeficiency virus type 1 (HIV-1) RNA (Abbott LCx HIV RNA Quantitative assay) has been compared with the Organon NucliSens assay on 521 retrospective samples obtained from HIV-1-positive patients monitored during highly active antiretroviral therapy, 79 of whom were assayed also by the Chiron Quantiplex 3.0 system and on characterized panels. The LCx system showed a moderate correlation (r = 0.795) and gave higher results than the NucliSens system on 245 of 327 concordant positive samples, with similar sensitivity. Correlation with Quantiplex system results was higher (r = 0.943). LCx reproducibility was very good; the procedure was simple, well controlled, and rapid (up to 48 results in 7 h). The HIV RNA quantitative assay on the LCx system is suitable for routine use.

Antiretroviral Therapy, Highly Active↗

PubMed2000

In vitro antimicrobial activity of propolis dry extract.

In this study the antibacterial and antifungal properties of propolis, a natural product of bees, have been investigated against different pathogens. Minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) were determined according to NCCLS standards on 320 strains including Staphylococcus aureus, Group A beta-hemolytic streptococci, Streptococcus pneumoniae, Moraxella catarrhalis, Haemophilus influenzae, Klebsiella pneumoniae, Escherichia coli, Proteus mirabilis, Pseudomonas aeruginosa and Candida albicans. Time-kill curves were assessed for susceptible microorganisms, testing 0, 0.5, 1, 2, 4 x MIC for propolis, by counting viable bacteria after 0, 3, 6, 24 hours and viable yeasts after 0, 3, 6, 24 and 48 hours. Propolis showed good antimicrobial activity against most of the isolates, particularly S. pneumoniae, H. influenzae and M. catarrhalis, but not against Enterobacteriaceae. Time-kill curves demonstrated bacteriostatic rather than bactericidal activity of propolis, the latter being evident only at high concentrations.

Candida albicans↗

PubMed2000

Antimycotic activity and phagocytosis effects of econazole in combination with ibuprofen isobuthanolammonium against vaginal strains.

Vaginal infections caused by Candida spp., other yeasts and Trichomonas vaginalis are problematic mainly due to the various factors involved in development of infection and to the failure of common treatments. In this study we investigated the presence of synergistic activity of econazole and ibuprofen isobuthanolammonium against 310 different vaginal isolates, by using the microdilution broth assay to test in vitro antimicrobial activity and the effect of the two drugs on phagocytosis and intramacrophagic cellular killing of mouse peritoneal macrophages. The effect of sub-inhibitory concentrations of econazole / ibuprofen isobuthanolammonium combination on Candida albicans germ tube formation was also evaluated. The in vitro antifungal activity of econazole was notably improved by addition of ibuprofen isobuthanolammonium. Macrophage killing of C. albicans was significantly increased by the two drugs and also germ-tube formation was significantly affected. We conclude that the addition of ibuprofen isobuthanolammonium to econazole provides better in vitro antifungal activity. However, further studies are needed to elucidate the in vivo action of this formulation.

Analysis of Variance↗

PubMed1999

Review of probiotics available to modify gastrointestinal flora.

There is evidence that the oral consumption of micro-organisms produces a protective effect on the gut flora. A significant number of studies suggests that probiotics might have beneficial effects on several microbial disorders of the gut, but it is very difficult to define the clinical efficacy of such products. In this review, we report the results of studies on traveller's diarrhoea (TD), antibiotic associated diarrhoea (AAD) and acute diarrhoea (AD) in which various probiotic preparations have been used in controlled trials and been shown to have a beneficial therapeutic or prophylactic effect.

Anti-Bacterial Agents↗

PubMed1999

Effects of three different fish oil formulations on Helicobacter pylori growth and viability: in vitro study.

Helicobacter pylori infection is currently treated with antimicrobial agents in combination with antacids. Recent studies have described the in vitro bactericidal activity of fish oils and polyunsaturated fatty acids on H. pylori, and reduced rates of duodenal ulcer in people with high intake of these substances. In this study we have tested the in vitro activity of three different fish oil formulations on H. pylori strains using the Kirby Bauer method and an in vitro antibacterial test on bacteria adhered to cellular monolayers. Our results demonstrate that one of the oils is active. In this study we cannot speculate on which component of the active oil is effective and its mechanism of action, but we hypothesize that a higher concentration of icosapentaenoic acid and docosahexaenoic acid occurs in the active oil. Further in vitro and in vivo studies are needed before proposing fish oils as treatment of H. pylori infection.

Agar↗

PubMed1998

Immunostimulating effect of oral glutamine.

Glutamine represents the principal metabolic substrate for all rapidly proliferating cells. Since part of the glutamine efficacy could be related to immunoregulating properties, we assessed the effects of orally administered glutamine on serum interleukin-2 (IL-2) levels and intestinal T-cell populations in 48 athymic (nude) mice. Twenty-four mice received a standard diet enriched by glutamine (added to drinking water at a 4% concentration), while the other 24 served as the control group and received the same diet without glutamine. In glutamine-fed animals, we observed a marked increase in IL-2 concentrations after 10 days of treatment in comparison with control group and a modest but significant increase in intestinal T-cell counts. These results suggest that oral glutamine is able to exert local and systemic immunostimulating activity that could be of relevance in the prevention of gut integrity and immune defense loss associated, for example, with trauma, surgery, and starvation.

Adjuvants, Immunologic↗

PubMed1998

Interference on Helicobacter pylori growth and adhesion by omeprazole and other drugs.

Helicobacter pylori is the causative agent of gastritis and a co-agent in other gastroduodenal diseases. Gastroduodenal ulcer and MALT-lymphoma in particular, regress when patients are administered antimicrobial agents to eradicate infection. Sometimes eradication is not definitive and is difficult to check. The aim of our study was to test the antimicrobial activity of omeprazole on H. pylori in comparison with ampicillin and other anti-H2 drugs (ranitidine and famotidine), and to evaluate their interference with bacterial adhesion of H. pylori. We also compared results of the agar dilution antibacterial sensitivity test on H. pylori to those obtained using a bacteria adherence to cell monolayers model, to see if drug activity was different against adhered bacteria. We evaluated omeprazole and ampicillin MIC90s (minimum inhibitory concentrations) against 20 H. pylori isolates by traditional agar dilution method and by exposing previously adhered bacteria to an Hep-2 monolayer to different drug concentrations. The activity against bacteria adhered to cell lines was evaluated by counting viable adhered bacteria after 1, 6, 12 hours of contact with drug. Interference with adherence to Hep-2 cells was also tested. Omeprazole and ampicillin MICs were comparable to other findings (omeprazole MIC90 was 12.5 microg/ml and ampicillin MIC90 was 0.016 microg/ml), while higher concentrations were necessary (4 x MIC90) against adhered bacteria. These findings suggest that MICs evaluated with traditional assays can have different predictivity than tests on adhered H. pylori.

Anti-Ulcer Agents↗

PubMed1998

Serum and bone concentrations of teicoplanin and vancomycin: study in an animal model.

Teicoplanin and vancomycin are antibiotics widely used in the therapy of bone and joint infections. The aim of this study was to compare bone and serum concentrations of each antibiotic in guinea pigs after administration of 50 mg/kg of teicoplanin or vancomycin by the intravenous route. Serum and bone concentrations were determined immediately before and 0.5, 1, 2, 6, 12 and 24 h after drug administration by means of high performance liquid chromatography. Teicoplanin concentrations were always higher than vancomycin levels. Area under the concentration/time curve was significantly greater for teicoplanin than for vancomycin. In bone, teicoplanin concentration increased up to 6 h, while vancomycin reached its peak after 2 h. Moreover, teicoplanin showed markedly higher levels at 6, 12 and 24 h than vancomycin. In conclusion, the ability of teicoplanin to penetrate bone in greater amount than vancomycin confirms the potential use of teicoplanin in the treatment of bone infections and in the prophylaxis of orthopedic surgery.

Analysis of Variance↗

PubMed1998

[Lights and shadows on the molecular diagnosis of hepatitis C].

The rational application of molecular biology to clinical diagnostics must take in consideration the economic demands, as the waste of sophisticated and expensive assays is of no use for the physician prescribing the assays and burdensome for the individual or the community paying them. Sometimes it is useless to apply to the molecular biology, and the information obtainable through serology answer our demands. This brief survey of the principal means available today for Hepatitis C diagnosis and monitoring, besides summarising the principles on which the different techniques are based, wants to underline the most noteworthy aspects of the different assays--from general indication to specific application to a single case--in the attempt to improve the efficacy of the test, which may be the right one at the right moment. There are qualitative and quantitative methods for viremia determination, which not always are alternative; on the contrary they must sometimes be complementary in order to obtain a complete clinical pattern. As a matter of fact the clinician should choose according to protocol susceptibility and considering what the expected viremia could be. The risk of false negatives is very dreadful for the clinician, as that of false positives (from contamination) is threatening for the laboratory, which must carry out more work than its capabilities consent. One must not misuse these diagnostic means, but they must be used correctly in order not to transform an important service into a harmful inefficiency with unpleasant consequences both for the physician and the patient.

DNA Probes↗

PubMed1997

Inhibition of in vitro growth of enteropathogens by new Lactobacillus isolates of human intestinal origin.

Three human Lactobacillus strains, coded B21060, B21070 and B21190, have recently been isolated. The strains show a series of features (acid and bile resistance, adhesion to various types of mucosal cell) which make them particularly promising for the preparation of probiotic products. In the present study, the ability of the strains to inhibit the growth of pathogens in coculture was investigated. Lactobacilli were incubated simultaneously or after one overnight growth with enterotoxigenic Escherichia coli, Salmonella enteritidis or Vibrio cholerae. After 24 and 48 h, bacterial counts of the pathogens and of the lactobacilli were performed. The results showed that these Lactobacillus strains inhibited the in vitro growth of E. coli and S. enteritidis under both conditions. Moreover, a cumulative effect was observed for mixtures of lactobacilli. In contrast, no significant inhibition of Vibrio cholerae growth was observed, provided that the pH of the medium was kept constant. The presence of the pathogens did not affect the growth of the Lactobacillus strains. Moreover, each of the Lactobacillus strains showed coaggregation ability with two pathogenic E. coli strains, namely ATCC 25922 and ATCC 35401.

Bacterial Adhesion↗

PubMed1996

Combinations of high-dose vecuronium and mivacurium provide similar paralysis and intubation conditions to succinylcholine in paediatric patients.

This randomized blinded study tested the hypothesis that equipotent doses of vecuronium and mivacurium given in combination could achieve onset times to 90% neuromuscular block (B90) and intubation scores similar to succinylcholine. Thirty children were randomly assigned to one of three groups as follows. Group Sux received a single dose (1 mg.kg-1) of succinylcholine followed by normal saline. Group V1M1 received 0.08 mg.kg-1 of vecuronium followed by 0.1 mg.kg-1 of mivacurium. Group V2M2 received 0.16 mg.kg-1 of vecuronium followed by 0.2 mg.kg-1 of mivacurium. Anaesthesia consisted of propofol, fentanyl, and nitrous oxide. Neuromuscular response was monitored by adductor pollicis electromyography (Datex NMT). Sixty s after administration of the first injection, the laryngoscopy began, with the anaesthesiologist scoring the ease of intubation on a four category scale as excellent, good, poor, or inadequate. Time from injection to B90 was 39 (2.6)s after succinylcholine, which was not significantly different from 48 (3.5)s after vecuronium 0.16 mg.kg-1 and mivacurium 0.2 mg.kg-1 (V2M2). Mean time to B90 for group V1M1 was 64 (4.7)s, which was significantly different from that in group Sux. The intubation score was 'excellent' for all patients in groups Sux and V2M2 and for only seven of ten patients in group V1M1. Only combination of vecuronium (0.16 mg.kg-1) and mivacurium (0.2 mg.kg-1) provided rapid onset of neuromuscular blockade and excellent intubating conditions comparable to succinylcholine 1 mg.kg-1. This combination did result in prolonged recovery times.

Child↗

PubMed1994

Escherichia coli: effect of fosfomycin trometamol on some urovirulence factors.

The aim of our study was to evaluate the interference of fosfomycin trometanol (F.T.), at subinhibitory concentrations (1/4 and 1/8 MICs), on some urovirulence factors of Escherichia coli (12 strains). We tested fimbriae production, adhesion to uroepithelial cells, hydrophobicity, motility and hemolysin production of E. coli grown in the presence or absence of F.T. The strains tested, grown in the presence of F.T. (1/8 MIC), were less capable of adhering to uroepithelial cells, had less hemagglutination and reduced motility. This behavior was enhanced at 1/4 MIC of F.T. The hemolysin production and hydrophobicity properties present in some of our tested strains also were significantly decreased when the E. coli were grown in the presence of sub-MIC concentrations of F.T. These results suggest that F.T. may be of clinical use as treatment for acute urinary tract infection and in pyelonephritis prophylaxis.

Bacterial Adhesion↗

PubMed1994

Impact of cefetamet-pivoxil on intestinal microflora: in vivo study.

In our study we considered the possible interference of cefetamet-pivoxil with the intestinal microflora. We used 60 germ-free mice in which an intestinal microflora similar to the human one had been implanted. They were treated with 14.3 mg/Kg/die (standard dose) and a 28.6 mg/kg/die (daily dose) of cefetamet-pivoxil by oral route. The results obtained in vivo proved that cefetamet-pivoxil at therapeutic doses does not influence the normal intestinal microflora.

Animals↗

PubMed1994

An experimental model to reproduce some bacterial intestinal cocultures in germ-free mice.

The objective of this study was to create a stable experimental model to act as a living incubator for the main important intestinal bacteria. We have therefore inoculated germ-free mice with the most important bacteria of the human intestinal microflora, in order to study the effect of some oral antibiotics on the intestinal microflora. Sixty germ-free mice, 7 weeks old and of either sex, were inoculated orally with human faecal bacteria by means of their drinking water. Administrations were made at regular intervals following a scheme that respected some of the metabolic inter-relationships of the microorganisms used. The results showed that colonization of the germ-free mouse intestines had been achieved by most of the bacteria that had been inoculated. This "coculture" was stable in time, contrary to what happens when in-toto lyophilized faeces are administered, and the bacterial concentrations for each strains were similar to those found in human faeces.

Animals↗

PubMed1994

Impact of ceftibuten on intestinal microflora: in vitro and in vivo studies.

The present study examines the possible interference of ceftibuten on intestinal microflora. In 60 germ-free mice, an intestinal microflora similar to the human one was implanted. The mice were then treated with a single dose and twice the therapeutic dose of ceftibuten. In another experiment, ten human volunteers were given ceftibuten in doses equivalent to 400 mg/day for 7 days in order to evaluate the ceftibuten faecal concentration, the possible interference on microflora and the quantity of indacan (as a measure of the bacterial metabolism in the gut) excreted in one day. The results obtained in vivo and in vitro have shown that ceftibuten in therapeutic doses does not alter the equilibrium of normal intestinal microflora.

Adult↗

PubMed1991

[The interference of miocamycin on the adhesiveness and coaggregation of the bacteria responsible for periodontopathies].

The authors studied the effect miocamycin has on the adherence and coaggregation of pathogenic bacteria in periodontopathy. The data obtained by optic microscopy, after treatment of the strains with doses of miocamycin equal to 1/4 and 1/8 of the MIC after 3 and 6 hours, shows the interference effect on the coaggregation and adhesivity of the antibiotic. These results have been confirmed by the observations obtained by scanning electron microscope (SEM).

Bacteria↗