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Biomedical subjects

V Vidotto

Publications and source records attributed to V Vidotto.

At least 37 records · Page 2Linked to original sources
PubMed1994

Effect of Aspergillus terreus extract on neoplastic and non-neoplastic cell replication.

There are very few and unconfirmed data regarding the antineoplastic activity of mycotic derivates in human cells. The effects on neoplastic and non-neoplastic cell replication of Aspergillus terreus extracts have been tested. In fact, among different species of Aspergillus mycotoxin producers. A terreus seems to be more suitable for hypothetical therapeutic purposes because of its low mycotoxin toxicity. Very evident antiblastic activity of alcoholic crude extract of A. terreus on tumor cells has been demonstrated. Doses between 3.1 and 6.2 inhibited more than 50% of tumor cells; the same effect was obtained with doses > 25 micrograms/ml on non-neoplastic cells. The action of the crude extract does not influence cellular cAMP in either neoplastic or non-neoplastic cells. The antiblastic action seems to depend primarily on the inhibitory effect of DNA duplication. Some chromatographed fractions of the mycotic extract showed inhibiting or enhancing effects on cell growth.

Animals↗
PubMed1993

Influence of different levels of ammonium concentrations on cell growth, RNA and protein production by Candida albicans.

Candida albicans starved cells were incubated in minimal synthetic liquid media containing different concentrations of ammonium sulphate (0.00, 0.02, 0.05, 0.10, 0.03, 0.50 g/L). Culture growth was monitored by measuring daily the optical density and by evaluating RNA and protein cellular content after 48 and 96 hours from the inoculum. The environmental availability of ammonium ion influenced the biomass production, that was maximum when its concentration was 0.10 and 0.30 g/L. In addition, an effect on cell duplication time was observed, this was particularly evident when the (NH4)2SO4 concentration was 0.10 g/L. The protein content increased in relation to the increase of ammonium ion availability, with a peak in correspondence to 0.30 g/L and a drop when the greatest concentrations were employed. RNA production was inversely proportional in respect to protein production. The optimal range of ammonium sulphate concentration for C. albicans growth was 0.10-0.30 g/L; over these concentrations there was an inhibitory effect. The rate of the protein and RNA syntheses seems to indicate the growth phase and the nitrogen nutritional conditions of the cultures, respectively.

Ammonium Sulfate↗
PubMed1992

Growth of Cryptococcus neoformans in a thiamine-free medium.

The growth of Cryptococcus neoformans in a minimal liquid synthetic medium with or without thiamine (10 micrograms/ml) was investigated. In these media the presence or absence of thiamine had no effect on the development of C. neoformans. To check these results, we performed a series of experiments on a solid form of the minimal synthetic medium. In this study a series of six serial transfers were carried out to starve the cells of nutrients that may have been carried over from their growth on rich media. In each of the transfers on the solid synthetic medium, C. neoformans showed a similar and scarce growth. This finding indicates that C. neoformans could be autotrophic in respect to thiamine.

Cryptococcus neoformans↗
PubMed1991

Optimal concentration of ammonium ion in a minimal synthetic medium for the growth of Candida albicans.

Candida albicans strain B 311-10 with and without starvation was cultivated in the minimal synthetic medium of Shepherd et al., modified without biotin, amino acids, low glucose concentration and with decreasing amounts of (NH4)2SO4, to determine the optimal growth requirement for this strain. All the experiments were carried out under sterile conditions at 25 degrees C in a thermostat with initial O.D.s (675 nm) of 0.500 and 0.100. Cell growth was generally monitored everyday for six days with a spectrophotometer by determining the absorbance of the cultures at 675 nm. All the experiments were repeated three times and a statistical analysis of the data with a probability of 99% and 1% of error was performed to confirm the validity of the results. Best growth was obtained with starved cells at an initial O.D. of 0.100 and with a 0.1 g/L concentration of (NH4)2SO4. At this concentration, the growth of C. albicans B 311-10 was best between the first and the fourth day with the maximum at the third day. With (NH4)2SO4 concentrations of 0.05 and 0.5 g/L, cell growth was the same.

Ammonium Sulfate↗
PubMed1991

A new minimal synthetic medium for germ-tube production in Candida albicans.

A new minimal synthetic medium, with low amount of glucose, without aminoacids, vitamins and neutral pH, which induces germ-tubes production in Candida albicans, is reported in this work. The results indicate a perfect agreement between the germ-tube test performed with the standard method in human or animal serum and this test performed in minimal synthetic medium. In this medium the germ-tube test for the presumptive identification of Candida albicans can be performed with the same formality, time and reproducibility as those in human or animal serum. This constitutes an interesting finding because it is easy to prepare, to store and is highly reproducible.

Candida albicans↗
PubMed1991

Candida albicans biotypes in human immunodeficiency virus type 1-infected patients with oral candidiasis before and after antifungal therapy.

A prospective 19-month study of 26 human immunodeficiency virus type 1-infected patients with episodes of erythematous or pseudomembranous oral candidiasis was done to evaluate the significance of Candida albicans biotypes in patients treated with antifungal therapy. Changes in the biotype of C. albicans were frequently noted in recurrent oral candidiasis. However, no correlation was found between the various biotypes and the clinical features of oral candidiasis, the clinical stage of human immunodeficiency virus type 1 infection, or the number of CD4+ lymphocytes. On the contrary, a significant correlation appeared among clinical lesion features, CD4+ cell numbers, and time of clinical disappearance of the oral lesions. Changes in the biotype of C. albicans were observed at the end of the antifungal therapy in 17 of 26 patients who had a second appearance of oral candidiasis as well as in 10 of 14 subjects who experienced a third reappearance of oral candidiasis.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Sporotrichosis in the metropolitan area of Cusco, Peru, and in its region.

Eight cases of sporotrichosis originating from the metropolitan area of Cusco, Peru, and its region are described, including the circumstances of infection and the isolation of Sporothrix schenckii from the lesions. This finding classifies this particular area with high altitude, low temperature and dry weather as an endemic zone of interest in the epidemiological and ecological study of Andean sporotrichosis. Among the eight cases observed, five were of the fixed cutaneous type and three were lymphocutaneous. Six patients were male and two female. Two paediatric cases were also observed. Therapy with potassium iodide was very satisfactory, whereas poor results were obtained with ketoconazole.

Adolescent↗
PubMed1990

[Biological properties of an alcoholic extract of Aspergillus terreus].

The following effects of Aspergillus terreus alcoholic extract are investigated: antiblastic and antiviral effect, and the ability of modification of interferon production and lymphocyte blastic transformation. In particular the extract showed more evident antiproliferative effect on transformed or EBV immortalised cells and lower effect on normal cells. Moreover doses from 12.5 +/- micrograms/ml depressed significatively the in vitro interferon production and lymphocyte blastic transformation induced by PHA on human cells. Mengo and Semliki Forest viruses replication was reduced, although temporarily, in the presence of 50 +/- micrograms/ml of the extract. Eventually the study of some fractions separated on chromatographic column demonstrated the contemporary presence of fractions able to inhibit or stimulate K-562 erythroleukemic cells replication.

Alcohols↗
PubMed1990

Growth of opportunistic yeasts on vitamin-free solid medium.

The growth of some opportunistic yeasts (Candida albicans, Cryptococcus neoformans, Torulopsis glabrata, Rhodotorula rubra, Geotrichum candidum, Trichosporon cutaneum, Saccharomyces cerevisiae) was essayed in a solid minimal synthetic medium without vitamins. From the preliminary results some species (Candida albicans, Cryptococcus neoformans, Rhodotorula rubra, Geotrichum candidum and Saccharomyces cerevisiae) seem to be autotrophic regarding the growth factor considered indispensable for their metabolism and for this reason normally added to the common synthetic media employed.

Candida↗
PubMed1988

Simple method for separating the chlamydoconidia of Candida albicans from its mycelium.

Different physical and chemical methods were used to detach the chlamydoconidia of Candida albicans from its mycelium. The action of concentrated H2SO4 acid for a 4-min period on cultures lysed both the mycelium and the outer but not the inner wall layer of the chlamydoconidia. The sulfuric acid procedure is recommended as the best method to obtain mycelium free chlamydoconidia because of its simplicity, rapidity and low cost.

Candida albicans↗
PubMed1988

Importance of some factors on the dimorphism of Candida albicans.

The passage between the yeast and mycelial forms of Candida albicans B 311-10 was studied by using the minimal synthetic medium of Shepherd et al. modified without biotin and with low glucose concentrations. It was observed that biotin, aminoacids and particularly pH are not important factors in the dimorphism of C. albicans. The only factor of notable importance in the passage of yeast form to mycelial form in C. albicans was glucose concentration.

Amino Acids↗
PubMed1988

A synthetic medium for Saccharomyces cerevisiae.

Growth of Saccharomyces cerevisiae strain Castelli 20 has been observed in a minimal synthetic medium using different glucose concentrations and without biotin, during the first 30 hrs of its development at 28 degrees C. The yeast's growth was observed spectrophotometrically at 675 nm reading the Optical Density every hour. The minimal medium of Sheperd et al. (1980), with glucose 15 g/L and biotin was modified: the vitamin was eliminated and the concentration of glucose was gradually reduced down to 0.5 g/L. At 5 g/L of glucose concentration and without vitamins the strain grew very well. From our results up to 30 hrs biotin has no influence on the yeast's growth. The medium would be useful to study Saccharomyces cerevisiae physiology during the early period of its development.

Biotin↗
PubMed1987

Growth of Candida albicans in a minimal synthetic medium without biotin.

Growth of Candida albicans strain B 311-10 was observed in a minimal synthetic biotin-free medium, using different glucose concentrations, during the first 30 hours of its development at 28 degrees C. The yeast's growth was observed spectrophotometrically at 675 nm reading its optical density every hour. The minimal medium of Shepherd et al., with glucose (15 g/L) and biotin was modified: this vitamin was eliminated and the concentration of glucose was gradually lowered to 0.5 g/L. At 5 g/L of glucose and without biotin very good growth was obtained. Based on our results during the first 30 hours of growth, biotin has no influence on the yeast's growth. This medium would be useful for the study of the physiology of C. albicans during the first period of its development.

Biotin↗
PubMed1986

Fungal colonization in patients with cancer of the upper respiratory tract.

Fungal opportunistic infections are a danger for immunocompromised hosts, such as patients with malignancies, especially in a hospital environment. We studied a group of patients with solid tumors of the respiratory tract on admission and after twenty days of hospitalization. Colonization by moulds and/or yeasts was frequently found. Preventive measures should be applied to avoid colonization inside the hospital. The importance of overcrowding, sanitation and diet is pointed out.

Female↗
PubMed1986

A new medium for the production of chlamydoconidia by Candida albicans.

Several isolates of Candida albicans were tested for production of chlamydoconidia and metabolic changes when grown on several different solid and liquid media. A liquid medium, consisting solely of sterilized skimmed milk and a solid medium containing processed cheese stimulated more rapid and greater production of chlamydoconidia than the corn meal agar and the other media tested.

Animals↗
PubMed1986

Sources of fungal contamination in a burn-care unit.

A microbiological study was carried out in the burn-care unit of the Centro Traumatologico Ortopedico of Turin (Italy) in order to detect the most important sources of fungal contamination in patients at high risk of infection. Identification of the fungi was carried out only for those of medical mycological interest, with the exclusion of the yeast isolates.

Air Microbiology↗
PubMed1986

In vitro activity of alpha, beta, gamma human interferons and Aspergillus terreus mycotoxins on cell proliferation.

The in vitro effect of different doses of alpha, beta and gamma human interferons and their interaction on the proliferation rate of human erythroleukemic cell line (K-562) and other cell lines has been evaluated. The results show that the stronger activity is exerted by beta HIF in comparison with alpha HIF. The action is selective and species-specific. beta HIF never elicited an "enhancing" effect on cell proliferation; on the contrary this phenomenon has been observed to occur with alpha and gamma HIF. In our cell system, the interaction between beta and gamma HIF gave a synergistic effect; on the contrary, no interaction has been observed to take place when beta HIF and directly cytotoxic mycotoxins extracted from A. terreus are associated.

Cell Division↗