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Biomedical subjects

F Poli

Publications and source records attributed to F Poli.

At least 127 records · Page 7Linked to original sources
PubMed1988

5-Azacytidine accelerates yeast-mycelium conversion in Candida albicans.

The effect of the DNA demethylating agent 5-azacytidine (5-azaC) on the morphological development of Candida albicans blastospores has been investigated by microscopic observations. It was found that this compound does not produce any morphogenetic effect when the cells are not induced to mycelial form. By contrast, on the induced cells, 5-azaC markedly accelerates the process of germ tube formation. In addition in the treated cells, yeast-mycelium conversion develops synchronously, whereas it is asynchronous and slow in the normal cells. These data indicate that, together with phenotypic modifications, modulation of gene activity by DNA demethylation occurs in Candida albicans during morphogenetic changes.

Azacitidine↗
PubMed1988

[Gram-negative bacteria folliculitis].

Gram-negative folliculitis was first described in 1968 and had since given rise to numerous publications. To our knowledge, no case has yet been published in France, although we observed 6 of them in 12 months. Between March, 1985 and March, 1986, samples of pus for bacteriological examination were obtained from all our patients with acnea vulgaris resistant to the standard treatment (i.e. oral tetracycline combined with topical applications of tretinoin or benzoyl peroxide), thus enabling us to detect patients who had a Gram-negative bacillus (GNB) in at least one pustule. Inflammatory and painful episodes were noted in every case. Tetracyclines, initially effective, gradually lost their activity. The lesions were always limited to the face and consisted of: either superficial small pustules located in the naso-labial line and on the upper lip and chin, associated with inflammatory papulopustular lesions of the cheeks and perioral region; or deeply sited and painful nodules of the cheeks. Various GNBs of the lactose-fermenting Gram-negative rod group were isolated from the superficial lesions, and a Proteus mirabilis strain from the deep lesions. The GNB was never found in all samples but only in 1 to 3 pustules. Four patients were treated with antibiotics proved to be active in vitro against the responsible organisms, and their lesions disappeared within a fortnight. Two patients were given isotretinoin in doses of 1 mg/kg/day with a satisfactory result after 2 and 3 months respectively. The prevalence of Gram-negative folliculitis is probably underestimated. The clinical picture is stereotyped. GNBs are found in some pustules but rarely in all.(ABSTRACT TRUNCATED AT 250 WORDS)

Acne Vulgaris↗
PubMed1988

Aberrant development of Trichophyton mentagrophytes hyphae cultured in the presence of Congo red.

When Trichophyton mentagrophytes colonies were placed on a medium containing 150 micrograms/ml of Congo red, a dye which prevents chitin fibrillogenesis, their growth rate was reduced. The newly formed mycelium, examined under an ultraviolet microscope, consisted of thick, curled and branched hyphae endowed with swollen tips and subapical bulges. Short-time exposure revealed that the major sites of dye accumulation were the extension zones. Normally structured hyphae arose from aberrant mycelia when they were transferred onto a dye-free medium. The phenomena observed suggest that Congo red alters the wall properties of the extension zone, by inhibiting the gradual conversion of chitin chains, synthesized at the extreme tip, into microfibrils of increasing size and density.

Congo Red↗
PubMed1987

Genetic factors in nonspecific bronchial hyperreactivity. An epidemiologic study.

We tested bronchial reactivity to carbachol in 50 asthmatics, healthy parents of 40 asthmatic children, and 70 healthy subjects with no personal or family history of asthma. Stepped doses of carbachol (0.1%) aerosol were given until a 50% drop in forced expiratory flow rate from 25% to 75% was observed, or until the subject had inhaled 80 of his or her own vital-capacity equivalent volumes of the aerosol. The area under the dose-response curve was computed. Histograms of the carbachol reactivity showed a bimodal distribution: 10% of normal subjects and 50% of nonasthmatic parents had values in the asthmatic range. In 85% of parent couples at least one of the two parents had bronchial reactivity without being asthmatic. Our findings suggest that bronchial reactivity to a cholinergic bronchoconstrictor indicates an autosomal-dominant pattern of inheritance.

Adolescent↗
PubMed1987

Exocytosis in Saccharomyces cerevisiae treated with congo red.

When dividing cells of Saccharomyces cerevisiae were exposed to the polysaccharide-binding dye Congo red, the walls and septa became sites of chitin accumulation. In addition, the cytoplasm showed many vesicles that were different from those accumulating in the growing bud and from the lytic vacuoles of the untreated yeasts. To obtain information about these membranous structures, living cells were observed under phase contrast and UV light microscopes. Furthermore, ultrathin sections of Congo red-treated cells were processed by cytochemical techniques to reveal the chitin areas. Observations suggest that the aberrant vesicles were involved in a secretory process, and that pre-assembled chitin was not among the components transported to the cell periphery.

Chitin↗
PubMed1986

The cadaver kidney transplant program of North Italy before and after cyclosporine.

NITp is an organization that since 1972 has served an area of approximately 17 million inhabitants through 8 transplant centers, 20 active donor-procuring centers, and 1 coordinating center. The activity of NITp can be divided into three historical periods. In the first period (1972-1977, 408 transplants), collaboration was initiated and protocols implemented. In the second (1978-1982, 592 transplants), a policy was established as follows: three deliberate transfusions of standard packed red cells were given pretransplant to all untransfused patients on the waiting list. Priority was given to immunized patients when an HLA-A, -B-compatible kidney was available and an effort was made to ensure at least two HLA-A, -B matches to nonimmunized patients. All transplanted patients were treated with conventional therapy (corticosteroids and azathioprine). Evaluation of data of this period showed that both graft and patient survival had increased; a center effect was evident; the policy of giving a kidney with at least two HLA-A, -B matches seemed to improve the results; and preformed panel-reacting antibodies had a negative effect on graft survival. The third period began in January 1983 when some centers in the NITp started to use CsA. By December 31, 1985, 589 of 863 transplants performed had been treated with CsA. Data analysis showed that CsA significantly increased the one-year success rate in both first and second transplants; other factors, such as HLA-A, -B and -DR matching, transplant center, old age of the kidney donor (51-60 years), and cold and warm ischemia times seemed less or not important. Preformed panel-reacting lymphocytotoxic antibodies did not influence graft outcome significantly, but a trend was observed in that immunized recipients did worse than non-immunized recipients. The transfusion effect could not be evaluated in our CsA patients since they all are transfused pretransplant; a prospective study is necessary to evaluate if such an effect is still present. Until more data are collected in our setting to allow a sound evaluation of the consequences of CsA treatment, no changes are warranted in the NITp policy.

Cyclosporins↗
PubMed1986

The effect of monensin on chitin synthesis in Candida albicans blastospores.

Monensin, a monovalent cation ionophore, was used to investigate some steps of the wall synthesis and morphogenesis in Candida albicans blastospores. In the presence of the drug, the pathogenic yeast developed enormous wall and septum thickenings that reacted intensely and specifically with wheat germ agglutinin and chitinase coupled to colloidal gold and fluorescein isothiocyanate. Therefore, the aberrant zones are interpreted as sites of chitin accumulation. The increased production of this homopolymer, also demonstrated by the chemical analysis of cell wall preparations, implies that monensin interferes in some way with the regulatory factors that normally control, in space and time, chitin synthetase activity.

Candida albicans↗
PubMed1984

Morphological anomalies induced by Congo red in Aspergillus niger.

Aspergillus niger germ tubes were exposed for 6 h to 0.15 mg/ml of Congo red, a stain which prevents chitin microfibril assembly. The most evident alterations, detected under ultraviolet light and by transmission and scanning electron microscopy, concerned the hyphal tips which burst or, most frequently, expanded into bulges. In the latter structures, new hyphal tips appeared which, after giving rise to more or less developed hyphae, were themselves converted into new bulges. Therefore, segments derived from isotropic and polarized growth alternated in the organisms exposed to the dye. An interpretation of these abnormalities is advanced based upon the assumption that the maintainance of a regular gradient of wall viscosity in the hyphal extension zone depends primarily on the capability of glycan chains to form crystalline aggregates of increasing complexity.

Aspergillus niger↗