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Biomedical subjects

E Grunberg

Publications and source records attributed to E Grunberg.

At least 37 records · Page 2Linked to original sources

Chemotherapeutic activity of 5-fluorocytosine and amphotericin B against Candida albicans in mice.

The effect of treatment with combinations of the two antifungal agents, 5-fluorocytosine (5-FC) and amphotericin B (AB), against systemic Candida albicans infections in mice was investigated. Graded doses of the single substances and of combinations of the drugs were administered daily for 21 days. The 50% curative dose (CD(50)) values were calculated on the basis of the presence or absence of C. albicans in cultures prepared from the kidneys of animals that succumbed during the experimental period or were sacrificed at the termination of the experiments. Overall, when graded doses of AB were administered in the presence of a constant, inactive dose of 5-FC (approximately one-half to one-fourth the CD(50) of 5-FC), the CD(50) values for AB were lower than those for amphotericin B alone. Similarly, the CD(50)s for 5-FC were reduced when AB was administered at a constant dose equal to one-half to one-fourth the CD(50) of AB alone. In no instance was there evidence of antagonism.

Amphotericin B↗

Inactivation of the hemagglutinins of type A influenza viruses by physical and chemical means: an aid to classification.

The effects of temperature and treatment with sodium dodecyl sulfate, Tween 20, dithiothreitol, trypsin, or guanidine on the hemagglutinating capacity of six strains of type A influenza virus (A(0)/PR8/34, A(1)/CAME/46, A(2)/J305/57, A(2)/Bethesda/63, A(2)/HK/Aichi/68, and A(2)/HK/80/68), one strain of swine virus (A/Swine/76/?), and one equine strain (A/Equi-2/63) were determined. The two Hong Kong strains could be readily distinguished from the earlier A(2) strains by the resistance of their hemagglutinins to trypsin treatment and their inability to recover hemagglutinating capacity after removal of dithiothreitol from treated virus preparations. In these respects, the equine strain most closely resembled the Hong Kong variants. The pattern of hemagglutination inactivation also set the swine, PR8, and CAME strains apart from each other as well as from the other five strains. The results suggest that separation of type A viruses into groups by the pattern of inactivation of their hemagglutinins may be a valuable adjunct to standard serology for a more definite classification of these viruses.

Animals↗

Effect of mg and ethylenediaminetetraacetate on the in vitro activity of coumermycin a(1) and novobiocin against gram-negative bacteria.

The effect of Mg(2+) and ethylenediaminetetraacetic acid (EDTA) on the in vitro activity of coumermycin A(1) and novobiocin was determined against Pseudomonas aeruginosa, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis grown in Trypticase Soy Broth or defined synthetic medium. In the presence of EDTA, the activity of coumermycin A(1) was significantly enhanced (8- to 40-fold) against all four organisms in the synthetic medium lacking Mg(2+); novobiocin activity was increased to a lesser extent (4- to 16-fold) against three strains and remained unchanged against P. mirabilis. Addition of 200 mug of Mg(2+) per ml to the synthetic medium containing EDTA completely reversed the enhancement of activity of both antibiotics by EDTA only against P. aeruginosa. The addition of Mg(2+) to the synthetic medium appreciably inhibited the activity of novobiocin (sixfold) but not coumermycin A(1) against E. coli, and had little or no effect on the activity of either antibiotic against the remaining organisms. K. pneumoniae showed the greatest susceptibility to both antibiotics, and addition of EDTA enhanced this activity from 4-fold to 20-fold in all of the media tested. Subinhibitory concentrations of both antibiotics induced filament formation by all four organisms in all media. In addition, lysis of K. pneumoniae cells was observed.

Journal Article↗

Automated technique for the detection of hemagglutinins to sheep erythrocytes.

The Technicon autoanalyzer system used for the detection of homologous human hemagglutinins has been modified for the detection of hemagglutinins to sheep red blood cells. Antibody quantitation was obtained by plotting the optical density (OD) readings of peak heights of a serially diluted reference serum versus the serum dilutions. When the OD of the peak height of an unknown sample fell within the linear portion of the plot, a direct determination of the antibody titer was made. If the OD of the sample fell outside the linear portion, dilutions of the sample were carried out until a direct reading could be made. Assay by this method of at least 140 samples was possible within a day. Titers obtained with the autoanalyzer agreed very closely with those obtained by manual titration.

Animals↗

Efficiency of a multitest system (Enterotube) for rapid identification of Enterobacteriaceae.

Enterotube, a multiple-test system which combines nine biochemical tests useful in the identification of members of the family Enterobacteriaceae, was tested and compared with the PathoTec test system in the identification of gram-negative bacilli isolated from clinical specimens. It was found that both the Enterotube and the PathoTec systems rapidly and accurately defined the position of the organisms in the major groups of the family Enterobacteriaceae. Discrepancies were noted between the results of citrate tests on Simmons' citrate-agar and in the Enterotube, as well as between Simmons' citrate-agar and the PathoTec citrate test. It was concluded that the Enterotube system provides a simple, reliable, and rapid method for the presumptive identification of Enterobacteriaceae. The major advantage of the Enterotube is that all tests are done simultaneously by inoculation from a single isolated colony.

Bacteriological Techniques↗