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Biomedical subjects

E W Lapa

Publications and source records attributed to E W Lapa.

10 recordsLinked to original sources
PubMed1988

Improved method for azole antifungal susceptibility testing.

A reproducible method is described for the determination of the MICs of ketoconazole, miconazole, fluconazole, and itraconazole with sharp endpoints when employed with either yeasts or molds. A semisolid medium is used with controlled pH and standardized inoculum. The time of reading results is a critical factor in the conduct of this test. The medium is simple to prepare and has a relatively long refrigerator shelf life in a user-ready state, requiring only the addition of a freshly prepared inoculum after restoration to room temperature.

Antifungal Agents↗
PubMed1984

Adherence of digested tissue sections for fungal immunofluorescence.

Specific immunofluorescence (IF) staining is helpful and often decisive in diagnosis of deep mycoses by examination of host tissue sections. Brightness of fluorescence may be significantly enhanced by prior digestion of tissues with trypsin, but the treatment tends to separate sections from slides. This is avoided by replacement of albumin in the process by an inexpensive commercial product, Elmer's Glue-All. The entire IF staining procedure for fungi in tissue sections is reviewed here, with emphasis on adhesion and digestion of sections.

Adhesives↗
PubMed1984

Phialophora parasitica, an emerging pathogen.

Monoconidial cultures derived from 12 clinical and environmental isolates of Phialophora parasitica were compared with respect to morphologic and physiologic characteristics and response to antifungal agents. No yeast cells were seen in 1- and 3-week-old slide culture preparations. Also, not all of the distinguishing characteristics of this species were displayed by all isolates on all media examined. Although the isolates grew on Sabouraud agar with chloramphenicol and cycloheximide, some inhibition was observed. All cultures were strongly urease-positive and hydrolyzed casein and starch; most decomposed tyrosine but not gelatin. All but one environmental isolate grew well at both 23 and 37 degrees C, but none grew at 40 degrees C. In the sensitivity testing the isolates did not vary much in their response to each drug, although some anomalies were observed. Amphotericin B and miconazole had minimum inhibitory concentrations in the low sensitivity range (2.0-8.0 and 2.5-10 micrograms m-1 respectively), for most isolates, and most isolates were resistant to both 5-fluorocytosine and ketoconazole. Limited observations were made on three other Phialophora species which might be confused with P. parasitica.

Amphotericin B↗
PubMed1980

Susceptibility of zoopathogenic fungi to phytoalexins.

Phytoalexins are a group of low-molecular-weight antibiotics produced by higher plants in response to infection by relatively avirulent microorganisms. They are of relatively low toxicity for mammalian cells and have been reported to possess a broad spectrum of antimicrobial activity against bacteria and phytopathogenic fungi. Employing a broth dilution technique, we have found the zoopathogens Petriellidium boydii, Aspergillus flavus, A. fumigatus, Candida albicans, Coccidioides immitis, Cryptococcus neoformans, Histoplasma capsulatum, Rhizopus oryzae, Sporothrix schenckii, and Trichophyton rubrum to be inhibited by one or more of the phytoalexins maackiain, medicarpin, phaseollin, phaseollin isoflavan, pisatin, sativan, and vestitol in concentrations of from 12.5 to 50 microgram/ml. Phaseollin isofalvan was the most effective of these. In agar cup diffusion tests growth of the yeast form of Blastomyces dermatitidis was inhibited by phaseollin at 50 microgram/ml and by phaseollin isoflavan at 25 microgram/ml. Susceptibility of the mycelial form of B. dermatitidis to these two compounds was demonstrated by inhibition of radial extension on agar plates.

Animals↗
PubMed1977

Modified indirect fluorescent-antibody test for aspergillosis.

Diffuse fluorescence in an indirect fluorescent-antibody test for antibody to Aspergillus fumigatus was eliminated by using germlings, rather than hyphae, as antigen. The modified method yielded diagnostic titers larger than or equal to 1:32 in 24 of 25 known cases, was highly specific, and showed good correlation with clinical status and results of immunodiffusion. This technique, which uses the germling antigen, inactivation of test serum at 59 +/- 1 degrees C, and anti-immunoglobulin G conjugate, is a sensitive, specific, and reliable quantitative indicator of aspergillosis and is useful in following the course of the disease.

Antibodies, Fungal↗
PubMed1976

Aspergillus oryzae meningitis.

In a patient with only meningitis, a septate hypha was seen in a Langhans giant cell, and the rarely pathogenic Aspergillus oryzae was cultured from the cerebrospinal fluid. Serologic results confirmed the diagnosis. The patient responded to therapy with amphotericin B and flucytosine.

Adult↗
PubMed1967

Micromorphology of Cryptococcus neoformans.

Fine details of the internal and external morphology of Cryptococcus neoformans as seen in ultrathin sections are described and illustrated with electron micrographs. The capsule characteristic of this species contained microfibrils (30 to 40 A in diameter) that appeared to radiate from the cell wall and to coil and intertwine in various directions. These thin, uniformly structured, electron-dense filaments are believed to represent complex polysaccharide molecules. The internal morphology of C. neoformans was in many ways similar to that of yeasts studied by other authors. The cell was uninucleate with a single nucleolus. The nuclear envelope, a pair of unit membranes interrupted by pores, was typical of that found in eucaryotic organisms. Smooth endoplasmic reticulum, mitochondria, vacuoles, storage granules, and ribosomes were consistent features of the cytoplasm. In addition, C. neoformans presented membranous organelles derived from the plasma membrane and comparable to bacterial mesosomes and mitochondria of an annulate type.

Cell Wall↗
PubMed1966

Durhamycin, a Pentaene Antifungal Antibiotic from Streptomyces durhamensis sp. n.

Durhamycin, derived from a previously undescribed soil isolate, is an apparently new antibiotic active against many of the fungi pathogenic for man and animals. Cultural and morphological characteristics and biochemical reactions of Streptomyces durhamensis are detailed. Methods of extraction of the antibiotic, physicochemical properties, antimicrobial spectrum, and results of mouse toxicity and protection tests are given.

Journal Article↗