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Biomedical subjects

D J Kitz

Publications and source records attributed to D J Kitz.

7 recordsLinked to original sources
PubMed1992

The effect of a mannose binding protein on macrophage interactions with Candida albicans.

A soluble mannose binding protein (MBP), obtained from rabbit serum, was found to inhibit phagocytosis of Candida albicans by bone marrow derived, cultured murine macrophages. During in vitro incubation of yeast with lymphocyte-free macrophage populations uptake of the yeast was significantly reduced at MBP concentrations of 5 micrograms/ml. A similar reduction in yeast phagocytosis was produced by dextrose, d-fucose, l-fucose, d-mannose and alpha-methyl-d-mannoside but required saccharide concentrations of 25-50 mg/ml. Inhibition of phagocytosis of the yeast also resulted from pretreatment of either the macrophages or the yeasts with MBP followed by washing. As expected, the addition of mannan to the assay medium blocked the inhibitory effect of MBP for uptake of C. albicans. These findings suggest that both cell bound and soluble mannose receptors may be important modulators of macrophage-Candida interactions.

Animals↗
PubMed1989

Clindamycin enhances murine delayed-type hypersensitivity and anti-candidal activity.

The contact sensitivity response of mice to dinitrofluorobenzene (DNFB), as determined by an epicutaneous painting and subsequent ear challenge assay, was enhanced by clindamycin administration. The optimal augmentation effect of clindamycin required its simultaneous administration at the time of DNFB skin sensitization. Clindamycin also was found to boost both in-vitro and in-vivo murine response to experimental infection with Candida lusitaniae. Intraperitoneal injection of 1-2 mg of the drug increased the clearance of yeast from organs after intravenous inoculation of mice. Clindamycin at concentrations of as low as 12.5 mg/l also increased the ability of cultured murine macrophages to kill the yeast without an increase in phagocytic activity.

Animals↗
PubMed1984

Growth inhibition of Cryptococcus neoformans by cloned cultured murine macrophages.

Cloned and unselected bone marrow-derived macrophage cell lines were obtained from A/J, AKR/J, BIO.A(5R), CBA/J, DBA/2, HPC, NZW, and [NZB X NZW]F1 mice, and their interactions were studied in vitro with a lightly encapsulated natural serotype A isolate of Cryptococcus neoformans. Growth inhibition of C. neoformans was seen with all of the cell lines, as determined by enumeration of colony-forming units. Inhibition was enhanced by a high concentration (8%) of fresh mouse serum and was the same for serum obtained from AKR/J (C5 deficient) and BIO.A (C5 normal) mice. Macrophage incubation with fresh AKR/J serum which had been absorbed with heat-killed Cryptococcus cells also inhibited C. neoformans growth. Heat-inactivation, EDTA addition or anti-C3 antibody treatment of fresh serum abolished the opsonic activity for C. neoformans, while EGTA addition to fresh serum was without effect on opsonization. In addition, neither IgM nor IgG1 murine monoclonal antibodies specific for C. neoformans enhanced phagocytosis or killing of the yeast by macrophages. These findings are consistent with the interpretation that C3b is an important modulator of interactions between macrophages and C. neoformans.

Animals↗
PubMed1983

The comparative virulence of thermotolerant Mucorales species in mice.

The comparative virulence of thermotolerant Mucorales was determined for cortisone-treated and untreated Swiss mice by intravenous administration of spores. The measure of virulence was based on an LD50 value, calculated after the 30-day observation period. Of the known etiological agents of mucormycosis, Mucor meihei, M. pusillus, Rhizopus arrhizus, R. chinensis, R. cohnii, R. microsporus, R. oryzae, R. rhizopodiformis and Cunninghamella elegans were able to produce fatal infections in mice; whereas, Mucor alternans, M. ramosissimus and Syncephalastrum racemosum were avirulent at dosages of up to 10(5) spores. Of those thermotolerant species which have not been reported to cause mucormycosis in human beings, Radiomyces embreei, R. spectabilis, Rhizopus oligosporus and Thermomucor indicae-seudaticae were found to produce fatal infections in mice; whereas, an isolate of Mycotypha africana was avirulent. Cortisone treatment of mice was found to lower their resistance to infection at a given spore dosage as measured by ET50 values.

Animals↗
PubMed1981

Comparative virulence of Absidia corymbifera strains in mice.

The comparative virulence of six different strains of Absidia corymbifera for cortisone-treated and untreated Swiss mice was determined. Spores of the six strains were inoculated into mice by the intravenous, intraperitoneal, and intranasal routes. All six strains were found to be virulent in cortisone-treated and untreated mice by the intravenous route. Up to a 16-fold difference in strain virulence was observed for cortisone-treated mice and up to a 10-fold difference for untreated mice. When spores were administered by the intraperitoneal route, 50% lethal dose values could be calculated only for the cortisone-treated mice, although a few deaths were seen in untreated mice challenged with 10(7) spores. Each of the six isolates of A. corymbifera, when administered in an intranasal dosage of 10(6) spores, produced death in some cortisone-treated mice. Studies made to determine the viability of spores produced by each strain revealed that germination was 90% or greater on Littman and YpSs agars at an incubation temperature of 40 degrees C in less than 12 h.

Animals↗
PubMed1980

Radiomyces a genus in the Mucorales pathogenic for mice.

The thermotolerant fungi Radiomyces spectabilis and R. embreei were tested for their ability to produce disease when injected intravenously into mice. All three strains of R. embreei tested were able to produce death in normal and cortisone-treated mice. Hyphal invasion was consistently observed in the kidneys of these animals, and involvement of the brain, heart and lungs was often seen at inoculum dosages of 10(4) and 10(5) spores. The single strain of R. spectabilis tested did not produce deaths; although cortisone-treated animals sometimes exhibited unilateral kidney involvement at necropsy.

Animals↗