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Biomedical subjects

J Guarro

Publications and source records attributed to J Guarro.

104 records · Page 6Linked to original sources
PubMed1980

Morphological changes in strains of Aspergillus flavus Link ex Fries and Aspergillus parasiticus Speare related with aflatoxin production.

Two strains of Aspergillus flavus Link ex Fr. and two strains of A. parasiticus Speare were cultured on crushed moist wheat (Triticum durum var. Pané no. 257) for aflatoxin production studies in correlation with morphological changes. The toxicogenic strains were adapted to the substratum by means of successive transfers at regular intervals (72 h.) The amount aflatoxins synthesized by the toxicogenic strains decreased gradually after succesive subculturing. The decrease was accompanied by marked morphological changes. One of the strains studied, A. flavus NRRL 3251, lost completely the capacity of aflatoxin synthesis after several subcultures, presenting at the same time strong morphological variations. A. flavus CBS 120.62 also lost its toxicogenicity after six subcultures.

Aflatoxins↗
PubMed1980

Air-borne fungi in Barcelona City (Spain). I. A two-year study (1976-1978).

Quantitative and qualitative studies were made of the fungi of the air in Barcelona City. The genera Cladosporium and Alternaria formed two of the most important components of the fungus population studied during a two-year period running from January 1976 through January 1978. Penicillium species formed the 16.3% of the total colonies while Aspergillus species represented only the 2.8%. The occurrence of the genera was greatly affected by climatic conditions. An attempt was made to summariza the data of various kinds of fungi on a volumetric basis. Most of the fungi reported here have been identified as far as genera.

Air Microbiology↗
PubMed1980

Air-borne fungi in the air of Barcelona (Spain). III. The genus Aspergillus Link.

During a survey on the presence of species of the genus Aspergillus in the air of the city of Barcelona (Spain), the following species were identified: Aspergillus flavus Link, A. niger van Tieghem, A. fumigatus Fresenius, A. clavatus Desmazières, A. terreus Thom, A. chevalieri (Mang.) Thom et Church, A. niveus Bloch, emend. Thom et Church, A. ochraceus Wilhelm, A. versicolor (Vuillemin) Tiraboschi, and A. amstelodami (Mang.) Church et Thom.

Air Microbiology↗
PubMed1980

Airborne fungi in the air of barcelona, Spain. V. The yeasts.

During a two-year survey of the fungal flora present in the air of Barcelona, Spain, the following species of yeasts were isolated: Sporobolomyces roseus Kluyver et van Niel, Candida albicans (Robin) Berkhout, Rhodotorula glutinis (Fres.). Harrison var. glutinis and Rhodotorula minuta (Saito) Harrison. Diurnal and seasonal incidences are presented.

Air Microbiology↗
PubMed1979

Air-borne fungi in the air of Barcelona (Spain). II. The genus alternaria.

The genus Alternaria Nees formed one of the more important components of the fungus population of the air at Barcelone (Spain), during a two-year study, from February 1976 through January 1978. Results were based only on studied of colonies obtained by gravity-exposed plates. The occurrence of this genus was greatly affected by climatic conditions. In general. however, Alternaria appeared to prefer warmer weather. A total of six species of Alternaria was identified, of which, Alternaria alternata (Fries) Keissler was by far the commonest, representing 71.3% of all colonies.

Air Microbiology↗
PubMedDate not supplied

Ultrastructural alterations produced by sertaconazole on several opportunistic pathogenic fungi.

Sertaconazole is a new synthetic antifungal which has shown promising activity against numerous fungi. The morphological changes induced by the drug at two concentrations, the MIC and 10 times the MIC, during 24 and 48 h on the filamentous opportunistic fungi Aspergillus fumigatus, Chaetomium atrobrunneum and Scedosporium prolificans indicated that the intensity of the ultrastructural breakdown depended on the dose and not on the time of exposure. Common severe alterations of many fungal cells, which could be considered beyond repair, were seen at the cell wall, plasmalemma and cytoplasm levels. The results obtained underline the drug efficacy for those fungi and suggest its applicability as therapeutic agent in the human infections produced by them.

Antifungal Agents↗
PubMedDate not supplied

Ultrastructural aspects of hair digestion in black piedra infection.

The ultrastructural pattern of human hair infection by Piedraia hortae in vivo has been studied. The fungus destroyed the cuticular layers of the hair and was able to penetrate deeply into the cortex. The course of destruction of human hair is described and compared with that produced by other fungi. Two well-defined types of cortex digestion were characterized. The slow rate of keratin degradation at the cortex together with the compacted stromatic organization of the nodules are argued as the main reasons that guarantee the long survival of the fungus, and therefore the chronic course of the disease. The data provided in this paper may help to understand the mechanisms that regulate the pathogenicity of this fungus.

Ascomycota↗
PubMedDate not supplied

Study of the invasion of human hair in vitro by Aphanoascus spp.

The course of the destruction of human hair in vitro by three species of the genus Aphanoascus (A. keratinophilus, A. fulvescens and A. verrucosus) was studied with light microscopy, and transmission and scanning electron microscopy. The results obtained show that all the three species develop keratinolytic activity. A. fulvescens and A. verrucosus have similar sequences of degradation, invading the hair through the cuticula, but without the presence of specialized erosive organs. A. keratinophilus, however, shows a different way of invasion, and the keratinolytic activity was mainly located in the cortex and from that point on expanded to the cuticula.

Ascomycota↗
PubMedDate not supplied

Fusarium infections. Criteria for the identification of the responsible species.

The incidence of human infections by Fusarium is increasing in contemporary medicine. Since the recognition of the species involved in such processes is generally difficult for non-specialists, we include here the main criteria that should be used in the identification of the responsible species. The most frequent species are F. verticillioides, F. oxysporum and F. solani, which are illustrated. The differences between Fusarium and Acremonium and Cylindrocarpon, two close genera, are discussed. The latter two are also illustrated. The main morphological characteristics of Fusarium such as sporodochium, conidiophore, conidiogenous cell, phialide, locus, macroconidia, mesoconidia, microconidia and chlamydospores are defined and illustrated. A key to the identification of Fusarium species isolated from human lesions is also included.

Animals↗
PubMedDate not supplied

In vitro susceptibility to itraconazole, clotrimazole, ketoconazole and terbinafine of 100 isolates of Trichophyton rubrum.

BACKGROUND: A reference method for dermatophyte in vitro susceptibility testing is lacking. With the advent of new antimycotics, susceptibility testing has received increasing attention as an important laboratory tool for aiding the selection of appropriate drug therapy. METHODS: One hundred strains of Trichophyton rubrum were tested against four antifungal agents, itraconazole, clotrimazole, ketoconazole and terbinafine, by using a modification of the proposed standard M38-P of the National Committee for Clinical Laboratory Standards and two types of standardized inocula, 1.4 x 10(4) and 5 x 10(3) CFU/ml. RESULTS: Terbinafine was revealed to be the most effective antifungal drug. Of the three azole derivatives tested, clotrimazole showed the highest antifungal activity, while the minimum inhibitory concentrations (MICs) of itraconazole and ketoconazole were similar. Inoculum size did not affect the MIC of any of the antifungal agents tested. CONCLUSION: Our preliminary data provide promising results for the development of a reference method for dermatophyte susceptibility testing based on the microdilution technique, although more dermatophytes should be tested and the method evaluated in different laboratories.

Antifungal Agents↗
PubMedDate not supplied

[Relation between meteorological conditions and the atmospheric microflora of the city of Barcelona].

This work deals with a study of the changes observed throughout the four seasons of the year concerning the number of fungi which can be found in the atmosphere of Barcelona. The results obtained will bring us to the conclusion that during the autumn and winter months the number of conidia per m3 is greater than in spring and summer. This observation would confirm the fact that generally speaking in autumn and winter, temperature decreases and humidity increases, while the opposite occurs in spring and summer. These phenomena would be directly related to our findings where we have established that an increase in temperature implies a reduction on the airborne fungi, while the remaining climatic factors taken into account would indicate an increase in the total fungal population. The same relation - phenomena were observed for the strains of the genus Cladosporium, Penicillium, Aureobasidium, Aspergillus and Alternaria, though with some modifications in the three later.

Air Microbiology↗