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Biomedical subjects

M G Bellotti

Publications and source records attributed to M G Bellotti.

At least 19 recordsLinked to original sources
PubMed2000

FT-IR microspectroscopy for microbiological studies.

In this article we present an infrared microspectroscopic investigation on Candida albicans microcolonies, taken as a model system for studies on other microorganisms. Excellent Fourier transform infrared (FT-IR) absorption spectra from 4000 to 850 cm(-1) have been collected in only 20 s from sampling areas of 100x100 microm(2) in microcolonies, which had been transferred from the agar plate onto zinc selenide (ZnSe) windows. When different regions within a single microcolony were investigated, absorption spectra with important differences in the carbohydrate absorption (from 1200 to 850 cm(-1)) were detected for the cells in the center and in the periphery of the colony. Results obtained on microcolonies grown on solid agar with increasing dextrose concentrations indicated that the observed spectral heterogeneity was related to differences in dextrose uptake, which was lower for the old cells in the center of the colony than for the metabolically active cells at the periphery. Although it is otherwise difficult to quantitatively evaluate the dextrose uptake in a microcolony, FT-IR absorption microspectroscopy offers a new and rapid method for the analysis of this process. The possibility of studying highly absorbing colonies by attenuated total reflection (ATR) by means of an ATR microscope germanium objective is also presented here for the first time. An evaluation of the contact area sampled by this technique is reported with a discussion of the spatial resolution, the quality and the potential of the ATR measurements.

Candida albicans↗
PubMed1998

[Candida albicans: the relationship between morphotypes and in-vitro adhesivity to the oral mucosa cells of HIV-positive and AIDS patients. I].

BACKGROUND: The significant frequency of oropharyngeal candidiasis due to C. albicans in HIV-infected and AIDS patients and the undoubted differences in pathogenicity among strains, lead us to study whether a possible correlation exists between the phenotypic characteristics of the fungal strain and the blastospores adhesivity to the human buccal epithelial cells. METHODS: From 203 oro-pharyngeal swabs of HIV-infected patients, 133 C. albicans were identified among 159 yeast strains. Analytical strains delineation below the species level was made by the morphotyping method, assigning a morphotype code of three digits, each of which being expressive of one colonial fringe characteristic. To study the possible blastospores adhesivity differences, we have isolated 10 strains of C. albicans, chose according to the more significant colonial morphologies; they were mixed with oral epithelial cells obtained by scraping of 36 HIV-positive patients and 2 volunteer donors HIV-negative at the rate cells/blastospores of 1:20. Suspensions were filtered, fixed and examined by optical microscope (MO) for counting the number of blastospores adhering to 100 epithelial cells and the number of cells with adhering blastospores. RESULTS: The index obtained by comparing the two qualitative analysis was higher for these isolates producing a rough or very coarse lateral fringes. CONCLUSIONS: This finding suggests that these strains may possess the highest adhesive properties, in fact the index decreases progressively to reach lower values for the strain not producing fringe.

AIDS-Related Opportunistic Infections↗
PubMed1996

Morphotypes of Candida albicans and their associations with underlying diseases and source of samples.

The morphotyping method was applied to differentiate a series of 276 Candida albicans strains recovered from hospitalized patients, by using a three-digit code based on the characteristics of the fringe outgrowth. By this scheme 32 different morphotypes were identified. An 86% reproducibility was achieved. The aim of this study was to investigate whether significant correlations exist between the morphotypes and: i) some underlying diseases of the patients, ii) the anatomical sources of the samples. The most striking associations were observed between fringeless strains and non-neoplastic diseases of the respiratory tract, and again between continuous filamentous fringe with parallel outgrowth and AIDS. With a significantly high frequency, samples from the genitourinary tract had a very coarse fringe texture.

Acquired Immunodeficiency Syndrome↗
PubMed1993

Susceptibility of Helicobacter pylori and pharmacokinetic properties in mice of new 5-nitroimidazole derivatives devoid of mutagenic activity in the Ames test.

The minimum inhibitory concentrations of metronidazole and four new 5-nitroimidazole derivatives (EU 11100, EU 11102, EU 11103, EU 11104), obtained by the reaction of 1-methyl-5-nitroimidazolyl-2-carboxyaldehyde and terbutyl-phenol, were determined against 25 clinical isolates of Helicobacter pylori. Three of them (EU 11100, EU 11103, EU 11104) exhibited an antibacterial activity higher than that of metronidazole. The last one, the molecule EU 11102, was less active than metronidazole. In mice, after a single equimolar oral administration, the molecules EU 11100 and 11103 were poorly absorbed and poorly excreted in urine. The molecular EU 11104 was well adsorbed and its urinary recovery was slightly lower than that of metronidazole. The substance EU 11102 was not demonstrable in blood and urine. In the Salmonella/microsome mutagenicity test only the molecule EU 11100 showed an increase of mutation frequency in S. typhimurium TA 100.

Animals↗
PubMed1993

Listeria monocytogenes infections: the organism, its pathogenicity and antimicrobial drugs susceptibility.

L. monocytogenes can induce serious, life-threatening infections. Multiple clinical manifestations of the disease include neonatal and perinatal listeriosis, infections in adult immunocompromised patients as well as in normal hosts, with the CNS as the more frequent site involved. Many outbreaks are believed to be food-borne in origin, but there can be other means of transmission. The susceptibility of L. monocytogenes to different antimicrobial drugs is reviewed. Many drugs that are highly effective in vitro show only a moderate activity in vivo, due either to their poor ability to enter the phagocytes and destroy the engulfed bacteria, as with the beta-lactams, ampicillin and amoxicillin, or to their bacteriostatic rather than bactericidal activity, as with the fluoroquinolones, or their affinity for a serum glycoprotein, as with the macrolide antibiotics. The bacterial killing appears to be enhanced by some synergistic drug associations, the best therapeutic results being achieved by trimethoprim-cotrimoxazole and ampicillin plus gentamicin. Other more recent antimicrobial drugs and drug combinations are still under clinical evaluation.

Anti-Bacterial Agents↗
PubMed1992

Antibacterial, antimycotic and trichomonicidal activity of a new nitroimidazole (EU 11100).

The antimicrobial profile of a new nitroimidazole derivative (5-nitro-1-methyl-imidazolyl-2-hydroxy-3 terbutylphenyl carbinol) has been studied. The in vitro activity of the new molecule has been evaluated against both aerobic and anaerobic bacteria, Trichomonas vaginalis, and mycetes, under suitable experimental conditions. The new compound was compared with ampicillin against aerobic bacteria; with metronidazole against anaerobic bacteria, lactobacilli and T. vaginalis; with nistatin and econazole against candida and with econazole and bifonazole against filamentous fungi. The new nitroimidazole derivative has been shown to be moderately active against some anaerobic bacteria belonging to both the Gram-positive and Gram-negative groups. Its inhibitory activity against T. vaginalis was similar to that of metronidazole.

Animals↗
PubMed1991

Antifungal activity of two benzofuran-imidazoles in different experimental conditions.

A number of experiments was performed in order to analyze the in vitro activity of two new benzofuran-imidazoles, IM/B/4-62 and IM/B/4-66. Studies included the determination of minimum inhibitory concentrations (MICs) on three culture media, at different pH values and at different inoculum sizes. Furthermore, the killing activity and induced resistance were determined. In all the experiments econazole, clotrimazole and bifonazole were the reference compounds. The best MIC values of the two new imidazoles were observed on modified Sabouraud's medium, at neutral pH and an inoculum size of 10(4) cells/ml. The two substances showed killing activity and no resistance was observed. On the whole, the more favorable results were obtained with the compound IM/B/4-66.

Antifungal Agents↗
PubMed1990

Microbiological patterns of four new imidazole derivatives.

The authors present an in vitro experimental study concerning the microbiological properties of four imidazole derivatives, with a piperazine group between two benzene rings. Seventy strains of Gram-positive and Gram-negative bacteria, 30 of yeasts, 14 of filamentous fungi and 10 strains of Trichomonas vaginalis were tested. The new compounds revealed a good inhibitory activity against Gram-positive bacteria, yeasts and dermatophytes. These results compare well with those obtained with the other known imidazoles. Moreover any mutagenic activity is absent.

Animals↗
PubMed1988

Pasteur yeasts system, a test-kit for yeasts identification. Its evaluation in comparison with three commercial methods and conventional procedures.

The Pasteur Yeasts System is a commercial prepared kit and scheme for the rapid (48 h) identification of 23 yeasts belonging to 7 genera. The method consists of two parts: a gallery of media to evaluate germ tube production, urease activity, tetrazolium reduction, cycloheximide sensibility and fermentation of three carbohydrates, and an auxanographic method to determine the assimilation pattern of 16 carbohydrates. This system was tested in comparison with API 20 C Auxanogram, Mycotube, Candida Check and conventional procedures to identify 40 yeast strains. Pasteur Yeasts System provided correct identifications for 97.5% of the organisms and proved to have a high reproducibility, accuracy and reliability. The method is useful and facilitates the identification of pathogenic yeasts from clinical specimens in the routine laboratory.

Evaluation Studies as Topic↗
PubMed1987

New benzofuran-imidazoles as antimycotic agents. II. In vitro studies.

Ten new imidazole derivatives, benzofuran-imidazoles, were studied in vitro to establish their antimycotic activity against 70 fungal strains, in comparison with three known imidazoles and, for the dermatophytes only, griseofulvin. A very high inhibitory activity against dermatophytes was shown by five of the new substances. The other filamentous fungi and yeasts showed a more marked variation in their susceptibility. However a good sensitivity of some isolates of Candida albicans and other yeasts was seen.

Antifungal Agents↗
PubMed1985

Siccanin: a new antifungal antibiotic with antidermatophytic properties. In vitro studies.

The in vitro antifungal properties of the antibiotic siccanin were determined by the minimal inhibitory concentrations (MIC) values against 51 fungal strains (yeasts and filamentous fungi). The comparison was made with econazole, clotrimazole, 5-fluorocytosine and griseofulvin. The results show the useful antidermatophytic activity of siccanin.

Arthrodermataceae↗
PubMed1984

In vitro evaluation of the antimycotic activity of a thiophene derivative.

The antifungal activity of the protiofate, a molecule derived from thiophene, was determined in vitro. For the testing, we determined the MIC values of 63 fungal strains (27 yeasts, 36 filamentous fungi, 14 of which were dermatophytes) at different pH values and different inoculum sizes. The comparison was made with econazole and clotrimazole. The results indicate that protiofate has good inhibitory activity vs yeasts at pH 7 and that it is active on filamentous fungi at pH 6.5 and 7.

Antifungal Agents↗
PubMedDate not supplied

Mucin-like carcinoma-associated antigen (MCA) in breast cancer: clinical experience at the National Cancer Institute of Milan.

Mucin-like Carcinoma-associated Antigen (MCA) is a glycoprotein belonging to the mucin family; it is defined by the monoclonal antibody b-12. Mucins represent an interesting group of tumor markers and are widely utilized in the clinical monitoring of neoplastic patients. These molecules show a certain degree of tissue specificity and MCA is preferentially associated with breast tissue. Several studies have demonstrated that patients with breast cancer usually have high MCA serum levels. In this paper the experience of the National Cancer Institute of Milan with the clinical use of MCA in breast cancer patients is reported. The observed sensitivity of the MCA test was poor in patients with early-stage disease, while it was acceptable in patients with advanced breast cancer. MCA concentrations appeared to be directly related to disease spread. A clear relationship was seen between MCA levels and lymph-nodal status. The highest MCA plasma levels were observed in patients with metastatic disease. In this group of patients the sensitivity of the test on the basis of a cut-off of 11 U/mL was 52%.

Adenofibroma↗
PubMedDate not supplied

Activity of two benzofuran-imidazoles, IM/B/4-62 and IM/B/4-66, against experimental infections with Candida albicans and Trichophyton mentagrophytes.

The therapeutic activity of two new benzofuran-imidazoles, IM/B/4-62 and IM/B/4-66, formulated as 1% cream, has been evaluated against Candida albicans and Trichophyton mentagrophytes by inducing experimental vaginal candidosis in female rats and dermatophytosis in female guinea pigs. Results of the treatment were compared with those obtained by the same therapeutic regimen carried out with bifonazole. IM/B/4-66 proved to possess superior antimycotic activity to that of IM/B/4-62 and similar to that of bifonazole in both infections. Nmaley vaginal candidosis was cured in all the treated in animals at 6 days post-inoculation and skin lesions were healed in 9 of 10 animals at 15 days after infection, with negative cultures from all the infected sites.

Animals↗