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M Casanova

Publications and source records attributed to M Casanova.

At least 91 records · Page 5Linked to original sources
PubMed1992

Characterization of cell wall proteins from yeast and mycelial cells of Candida albicans by labelling with biotin: comparison with other techniques.

Candida albicans ATCC 26555 blastoconidia and blastoconidia bearing germ tubes were metabolically labelled by incubating the cells with 14C-labelled protein hydrolysate and were subsequently tagged with biotin. Double-labelled (radioactive and biotinylated) cell wall proteins and glycoproteins were extracted from intact cells of both growth forms by treatment with 2-mercaptoethanol (beta ME) and with beta-glucanases (Zymolyase) after treatment with beta ME. The beta ME- and Zymolyase-extracts were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and western blotted (immunoblotted) to nitrocellulose paper. Polyacrylamide gels were stained with Coomassie blue and processed for fluorography. Western blot analysis was performed either with peroxidase conjugated-concanavalin A (ConA) or Extravidin. Blotted proteins were also reacted with polyclonal antibodies and monoclonal antibodies against mannoprotein components from mycelial cell walls of the ATCC 26555 strain. Labelling with biotin allowed identification of a complex array of cell wall protein and glycoprotein components within a very wide molecular mass range (from 650 to 13 kDa). These appeared to be genuine cell wall components. Biotinylated high-molecular-mass glycoproteins that were not stained with Coomassie blue or that appeared as poorly resolved polydisperse bands by indirect ConA-peroxidase staining of Western blots were detected as sharply defined bands following reaction with the Extravidin-peroxidase conjugate. Biotinylated molecules retained unaltered reactivities against ConA, polyclonal antibodies, and monoclonal antibodies.

Antigens, Fungal↗
PubMed1992

Comparison of immunocytochemical and Holzer's methods for detection of acute and chronic gliosis in human postmortem material.

Immunocytochemical staining for glial fibrillary acidic protein (GFAP) allows more specific identification of astrocytes and their processes than classical histochemical techniques and has therefore recently been used by some investigators to quantify gliosis. However, although the immunocytochemical method is superior for delineation of reactive astrocytes, the examples presented here and previous work by others demonstrate that chronic fibrillary gliosis may be best detected by Holzer's method and not by GFAP immunocytochemistry. The authors' studies indicate that if, as in a recent study of gliosis in schizophrenia, computer-assisted densitometry is to be used to measure gliosis, the immunoperoxidase method may not be a sensitive technique to demonstrate glial changes in human postmortem material.

Brain↗
PubMed1992

[Endocarditis caused by Brucella melitensis on a mitral valve prosthesis presenting as an ischemic cerebrovascular accident].

A new case of endocarditis by Brucella melitensis on a mitral valve prosthesis in a 15 year old patient, whose first manifestation was an ischemic cerebrovascular accident is reported. The patient presented with daily fever only two months later. Medical treatment alone was not sufficient to avoid valvular failure and substitution of the prosthesis was required. The clinical manifestations and complications of this infrequent condition is discussed. Treatment, which often requires the combination of surgery and antibiotics administered over a prolonged period, is highly recommended.

Adolescent↗
PubMed1991

Covalent binding of inhaled formaldehyde to DNA in the respiratory tract of rhesus monkeys: pharmacokinetics, rat-to-monkey interspecies scaling, and extrapolation to man.

DNA-protein cross-links were formed in the respiratory tract of rhesus monkeys exposed to [14C]formaldehyde (0.7, 2, or 6 ppm; 6 hr). Concentrations of cross-links (pmol/mg DNA) were highest in the mucosa of the middle turbinates; lower concentrations were produced in the anterior lateral wall/septum and nasopharynx. Very low concentrations were found in the larynx/trachea/carina and in the proximal portions of the major bronchi of some monkeys exposed to 6 ppm but not to 0.7 ppm. No cross-links were detected in the maxillary sinuses or lung parenchyma. The pharmacokinetics of cross-link formation in the nose were interpreted using a model in which the rate of formation is proportional to the tissue concentration of formaldehyde. The model includes both saturable and nonsaturable elimination pathways and describes regional differences in DNA binding as having an anatomical rather than a biochemical basis. Using this model, the concentration of cross-links formed in corresponding tissues of different species can be predicted by scaling the pharmacokinetic parameter that depends on minute volume (V) and quantity of nasal mucosal DNA (MDNA). The concentration-response curve for the average rate of cross-link formation in the turbinates, lateral wall, and septum of rhesus monkeys was predicted from that of F-344 rats exposed under similar conditions. There was significant overlap between predicted and fitted curves, implying that V and MDNA are major determinants of the rate of cross-link formation in the nasal mucosa of different species. Concentrations of cross-links that may be produced in the nasal mucosa of adult men were predicted based on experimental data in rats and monkeys. The results suggest that formaldehyde would generate lower concentrations of cross-links in the nasal mucosa of humans than of monkeys, and much lower concentrations in humans than in rats. The rate of formation of DNA-protein cross-links can be regarded as a surrogate for the delivered concentration of formaldehyde. Use of this surrogate should decrease the uncertainty of human cancer risk estimates derived by interspecies extrapolation by providing a more realistic measure of the delivered concentration at critical target sites.

Animals↗
PubMed1991

Identification of germ tube cell wall antigens of Candida albicans.

The reactivity of affinity-purified antibody to two components of germ tube cell wall extracts of Candida albicans showed that the components shared a common determinant(s). Surface expression of at least one of these determinants was demonstrated by indirect immunofluorescence where antibody binding was observed only on the hyphal extension of the organism.

Antigens, Fungal↗
PubMed1991

Cell wall glycoproteins of Candida albicans as released by different methods.

Different methods of extraction frequently used in other studies were used to release glycoproteins from both intact cells and isolated cell walls of yeast and hyphal forms of Candida albicans. Extracts were obtained from whole cells by treatment (i) with 2-mercaptoethanol (beta ME) at pH 8.6 and 37 C degrees and (ii) with zymolyase after treatment with beta ME. Extracts were obtained from isolated and washed cell walls (i) by boiling with beta ME and sodium dodecyl sulphate (SDS), (ii) by boiling with SDS and (iii) by treatment with zymolyase after SDS. The extracts were separated by SDS-polyacrylamide gel electrophoresis and analysed by Western blotting with four reagents. Analysis with concanavalin A (ConA) revealed different glycoprotein populations depending on the treatment. Three possible germ-tube-specific constituents were observed; and 80 kDa component released by beta ME from both intact cells and cell walls, and 47 kDa and 43 kDa moieties released by zymolyase only from intact cells. MAb 4C12, specific for the protein portion of a large germ tube constituent, recognized polydisperse material which just entered the gel in beta ME extracts and in the region extending up from 200 kDa to near the top of the gel in zymolyase extracts. MAb 24.17, specific for a carbohydrate determinant of yeast phase cells, reacted with disperse material in the region from the top of the gel to one-third to two-thirds the distance to the 220 kDa mass marker. Antiserum specific for the serotype A determinant of mannan reacted with large disperse component(s) migrating in the region from the top of the gel to about two-thirds the distance to the 220 kDa mass marker and with a 180 kDa component. The components recognized by MAb 4C12, but not those recognised by MAb 24.17 and serotype A antiserum, were effected by treatment with endo-beta-N-acetylglucosamidase H. The various analyses revealed that the method of extraction affected the composition and size of the constituents recognized by the reagents.

Antibodies, Monoclonal↗
PubMed1991

Antigenic cell wall mannoproteins in Candida albicans isolates and in other Candida species.

Polyclonal antibodies (pAbs) and monoclonal antibodies (mAbs), raised against mannoprotein components from Candida albicans ATCC 26555 (serotype A) blastoconidia and mycelial cell walls, were used to investigate antigenic similarities among wall mannoproteins from other C. albicans serotype A and B strains, and from C. tropicalis and C. guilliermondii. Radioactively labelled walls isolated from cells grown at either 28 degrees C or 37 degrees C were digested with a beta-glucanase complex (Zymolyase 20T) to release cell-wall-bound mannoproteins. Numerous molecular species with different electrophoretic mobilities were released from the various isolates. Differences appeared to be related to both the organism and the growth temperature. Among the major protein components solubilized were mannoproteins larger than 100 kDa (high molecular mass mannoproteins), heterogeneous in size in most cases. Antigenic homology was detected among the cell wall high molecular mass mannoproteins of the two C. albicans serotype A isolates, whereas significant qualitative and quantitative differences were detected between serotype A and serotype B cell-wall-bound antigenic profiles. Moreover, C. tropicalis and C. guilliermondii wall antigenic determinants were not recognized by the preparations of pAbs and mAbs raised against C. albicans walls. A mannoprotein with a molecular mass of 33-34 kDa was present in the enzymic wall digests of all the organisms studied. When probed with pAbs raised against the protein moiety of the 33 kDa cell wall mannoprotein of Saccharomyces cerevisiae, antigenic cross-reactivity was observed in all cases except C. tropicalis. There appear to be significant antigenic differences between the mannoproteins of different isolates of C. albicans, and between those of C. albicans and other Candida species.

Antibodies, Monoclonal↗
PubMed1991

Phosphate-containing proteins and glycoproteins of the cell wall of Candida albicans.

The distribution of phosphate, carbohydrate, and protein in the cell wall components extracted from intact yeast cells of Candida albicans by beta-mercaptoethanol (beta ME) at pH 8.6 was examined by analysis of the material separated by DEAE-cellulose chromatography. All protein peaks did not coincide with peaks of both carbohydrate and phosphate. Subsequent analysis was performed on material obtained from yeast cells and germ tubes which were grown in medium containing [32P]phosphate. Two extracts were obtained by treating cells with beta ME or with zymolyase following beta ME. The extracts were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, followed by autoradiography. beta ME-extracted material contained high-molecular-mass (HMM), greater than or equal to 200 kDa, polydisperse material and a major and minor band of 19 to 20 kDa, Zymolyase extracts contained (i) three components of less than or equal to 40 kDa, one of which may correspond to the major beta ME band; (ii) four bands within the HMM region which may correspond to previously reported bands; and (iii) one band of 100 to 120 kDa. After longer exposures, additional midrange bands were detected in the zymolyase extract. In extracts treated with endo-beta-N-acetylglucosaminidase H, the HMM polydisperse material increased in mobility although retaining sufficient radiolabel for detection. Western immunoblot analysis of extracts with germ tube-specific antiserum and a germ tube-specific monoclonal antibody and concanavalin A showed that not all components contained detectable phosphate, not all glycoproteins contained detectable phosphate, and at least one 19- to 20-kDa protein may be phosphorylated in the absence of carbohydrate.

Acetylglucosaminidase↗
PubMed1991

Characterization of cell wall proteins of yeast and hydrophobic mycelial cells of Candida albicans.

Cell surface hydrophobicity (CSH) of blastoconidia and blastoconidia bearing germ tubes of Candida albicans ATCC 26555 was monitored by assessing attachment of polystyrene microspheres to the cell surface, and we found that mature hyphae were significantly hydrophobic. Treatment of intact cells with low concentrations of beta-glucanase (Zymolyase 20T) or proteases abolished or significantly reduced attachment of latex beads to hyphae. This effect paralleled an obvious reduction in CSH of the entire cell population, as measured by an aqueous-hydrocarbon biphasic partitioning assay. Analysis of the cell wall material released by Zymolyase and adsorbed on polystyrene microspheres indicated that germ tube-specific cell wall proteins and mannoproteins with apparent molecular masses of 20 to 67 kDa may be responsible for the hydrophobicity of hyphae. Zymolyase released from blastoconidia cell walls a different set of proteins and mannoproteins that were able to adsorb to polystyrene microbeads. Such molecular species might in turn be responsible for the CSH exhibited by blastoconidium populations as determined by the biphasic partitioning assay, although these probably hydrophobic components can be masked on the surface of blastoconidia, as the latter had no or very few latex microspheres attached to their surfaces. Treatment of cells of both C. albicans morphologies with 2-mercaptoethanol released qualitatively distinct species of polystyrene-adsorbed proteins and mannoproteins from yeast and mycelial cells. These observations suggested that hydrophobic proteins and mannoproteins that could be associated with CSH are bound to the cell wall structure through diverse types of linkages.

Adsorption↗
PubMed1990

Wall mannoproteins in cells from colonial phenotypic variants of Candida albicans.

Candida albicans ATCC 26555 switched at high frequency (10(-1) to 10(-3)) between several phenotypes identified by colony morphology on a defined mineral amino-acid-containing agar medium supplemented with arginine and zinc (LAZ medium). When cells taken from colonies exhibiting distinct morphologies were plated directly onto LAZ agar, spontaneous conversion to all the variant phenotypes occurred at combined frequencies of 2.1 x 10(-1) to 9.5 x 10(-3). However, when cells taken from the different colonial phenotypes were plated directly onto an undefined medium (yeast extract/peptone/dextrose; YPD medium), or first incubated in liquid YPD medium and then cloned on YPD agar, all colonies observed exhibited the same phenotype (smooth-white). When cells from the smooth-white colonies were plated as clones on LAZ agar, the original switch phenotype reappeared. These results suggest that environmental conditions such as the growth medium (and possibly the temperature) influence switching by suppressing phenotype expression, but have no effect on genotype. The variant colony morphologies also appeared to be associated with differences in the relative proportions of yeast and mycelial cells. Zymolyase digests of wall preparations obtained from cells belonging to different colonial phenotypes were analysed by SDS-PAGE. After blotting to nitrocellulose paper, the mannoproteins were stained with Concanavalin A, with a polyclonal antiserum enriched in antibodies against mycelium-specific wall components, and with a monoclonal antibody raised against a high-molecular-mass mannoprotein band (260 kDa) specific to the walls of mycelial cells. The results suggest that phenotypic switching might be associated with changes in the degree of glycosylation in high-molecular-mass mannoproteins, or in the way these mannoproteins are bound to other cell wall components.

Candida albicans↗
PubMed1990

Fab fragments from a monoclonal antibody against a germ tube mannoprotein block the yeast-to-mycelium transition in Candida albicans.

Fab fragments prepared from the immunoglobulin G monoclonal antibody (MAb) 4C12, which reacts with a determinant expressed on the hyphal extension of germ tubes of Candida albicans, inhibited germ tube formation, but intact MAb 4C12 did not. Indirect immunofluorescence showed a punctate binding pattern on cells incubated with Fab fragments but a confluent binding on cells incubated with intact MAb 4C12.

Antibodies, Monoclonal↗
PubMed1989

Covalent binding of inhaled formaldehyde to DNA in the nasal mucosa of Fischer 344 rats: analysis of formaldehyde and DNA by high-performance liquid chromatography and provisional pharmacokinetic interpretation.

Inhalation of 3HCHO and H14CHO (6 ppm, 6 hr) resulted in the formation of DNA-protein crosslinks in the rat nasal respiratory mucosa. The DNA was extracted and was fractionated into aqueous (AQ) and interfacial (IF) portions. AQ DNA and IF DNA were enzymatically hydrolyzed to deoxyribonucleosides in Tris buffer and analyzed by HPLC with liquid scintillation counting (LSC). HCHO was bound exclusively to the IF DNA, indicating that the HCHO was bound as DNA-protein crosslinks. Hydrolysis of the DNA quantitatively released the HCHO; no evidence was obtained for the formation of hydroxymethyl adducts. An adduct detected previously following incubation of mammalian cells with HCHO, N6-hydroxymethyldeoxyadenosine (hm6dA) [Beland, F.A., Fullerton, N.F., and Heflich, R.H. (1984) J. Chromatogr. 308, 121-131], was shown to be produced by reaction of HCHO with deoxyadenosine (dA) in bis-Tris buffer under conditions similar to those used for hydrolysis of the DNA. This reaction does not occur in Tris buffer. Evidence was obtained that most or all of the hm6dA observed can be explained by this reaction. Based on these results, an improved method to determine the amount of H14CHO bound to DNA was developed: the DNA is hydrolyzed in Tris buffer and analyzed by HPLC, and the released H14CHO is derivatized with dimedone and quantitated by LSC. Rats were exposed to a wide range of H14CHO concentrations (0.3, 0.7, 2, 6, or 10 ppm; 6 hr). DNA-protein crosslinking occurred at all concentrations. The formation of crosslinks was interpreted in terms of a nonlinear pharmacokinetic model incorporating oxidation of inhaled HCHO as a defense mechanism. The slope of the fitted concentration-response curve at 10 ppm is 7.3-fold greater than at 0.3 ppm, and the detoxication pathway is half-saturated at an airborne concentration of 2.6 ppm.

Animals↗
PubMed1989

Identification of wall-specific antigens synthesized during germ tube formation by Candida albicans.

Walls of the two cellular forms (blastoconidia and mycelia) of Candida albicans ATCC 26555 were obtained from cells metabolically labeled (6-h pulse) with 14C-protein hydrolysate and [3H]threonine. Walls were purified by thorough washings with buffered and sodium dodecyl sulfate solutions and digested with Zymolyase 20T. The enzymatic treatment released four major high-molecular-weight mannoproteins (HMWM), with apparent molecular masses of 650, 500, 340, and 200 kilodaltons (HMWM-650, HMWM-500, HMWM-340, and HMWM-200, respectively), from yeast cells, whereas two high-molecular-mass mannoproteins (HMWM-260 and HMWM-180) were solubilized from mycelial cells. Some additional minor low-molecular-weight species were also detected in the enzymatic digests of walls from both types of cell. Single and dual pulse-chase experiments indicated that the HMWM-260 and HMWM-180 species reflect de novo synthesis of new proteins specific for the mycelia and do not represent a topological rearrangement of blastoconidium wall components. Monoclonal antibodies were raised against the HMWM-260 species (quantitatively the predominant component in the mycelial walls), and polyclonal rabbit antibodies were obtained against yeast or mycelial cell walls. Anti-mycelial cell wall polyclonal antibodies were adsorbed to whole killed blastoconidia to remove antibodies against common blastoconidium and mycelial wall antigens. Titration by enzyme-linked immunosorbent assay revealed that the monoclonal antibodies could recognize an epitope of the protein moiety of the HMWM-260 mannoprotein. Immunoblotting and immunofluorescence techniques using these monoclonal and polyclonal antibodies confirmed that the HMWM-260 and HMWM-180 species are specific components of the envelope of the mycelial cell walls.

Animals↗
PubMed1989

[Disorders of bladder emptying following Burch colposuspension].

Forty patients with recurrence urinary stress incontinence (RUSI) were evaluated before and after Burch-colposuspension for voiding difficulties. Thirty-two (80%) patients were cured. Seven females developed an urge incontinence in the postoperative course, one female an urge plus stress incontinence. Residual urine was found in 6 of 7 patients with urge incontinence, in 5 patients a urinary tract infection. Four patients with urge incontinence after colposuspension were insulin dependent diabetics. In 18 patients residual urine was found in the postoperative course, only 6 patients were symptomatic with urge and urinary tract infection. We see a limited indication for Burch colposuspension in RUSI with reduction in vaginal mobility, detrusor hypocontractility, detrusor instability and in diseases predisposing to neurogenic bladder disorders.

Female↗
PubMed1989

[The cochlea and underwater diving].

Internal ear barotrauma are dangerous for cochlea. Out of accidents, long-term scuba diving involves no deafness. A study carries on 272 skin divers of the French Navy shows that only presbyacusis and industrial noise exposure give audiometric damages.

Adult↗