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K Pezzella

Publications and source records attributed to K Pezzella.

7 recordsLinked to original sources
PubMed1989

Flow cytometric analysis of the effect of interleukin-1 administration on bone marrow populations in mice.

We have examined the effect of administration of human interleukin-1 (IL-1) beta on bone marrow populations in mice. The bone marrow population was characterized by flow cytometric analysis of cell volume, right angle light scatter, and cell surface markers. The bone marrow population demonstrated significant alterations following the injection of a single dose of IL-1. The earliest response was a loss of granulocytes, which was followed by an expansion of cells in this population. There was also an accumulation of kappa chain positive B cells 24 h following administration. These cells were lost from the marrow over the next 48 h, accompanied by an expansion of precursor cells. The changes in cell populations were not due to contaminating lipopolysaccharide (LPS), although the effects could be mimicked by injection of high doses of LPS. Significant effects could be detected with single dose administration of 10 micrograms to 10 ng of IL-1 per animal. The effects of a single high dose (10 micrograms) were mimicked with multiple injections of low doses (5 x 10 ng), suggesting that the intensity of the response is related to the pharmacokinetics of IL-1. These results indicate a potent effect of IL-1 administration on murine bone marrow granulocyte and B lymphocyte populations. The studies described offer a means for the analysis of the effects of IL-1 in vivo.

Animals↗
PubMed1987

Muteins of human interleukin-1 that show enhanced bioactivities.

Using recombinant DNA techniques, we have made a series of amino-terminal muteins of human interleukin-1 (IL-1). Two of the muteins demonstrated 4-7-fold increase in bioactivity as compared to that of the native IL-1. The enhanced biological potency coincides with an increase in both receptor binding affinity and in vivo tumor inhibitory activity. By site specific mutagenesis, we have shown that the arginine at the fourth position of IL-1 is one of the key residues in the function of IL-1. Circular dichroism studies of the amino-terminus analogs showed little structural rearrangement. The change in bioactivity might be due to a change in the stability of the muteins, in the side chain interactions with receptors or in the minor change in folding near the receptor binding site.

Amino Acid Sequence↗
PubMed1987

High-level expression in Escherichia coli of a soluble and fully active recombinant interleukin-1 beta.

A complementary DNA sequence encoding monocyte interleukin-1 (IL-1), beta form/pI7, was expressed in Escherichia coli. Recombinant plasmid pDP516 was constructed by cloning and rebuilding the mature IL-1 coding sequence into an E. coli expression vector. Bacteria transformed with pDP516 constitutively produced recombinant IL-1 (r-IL-1) at 15-20% of total E. coli protein. The r-IL-1 was found to be in the soluble fraction of sonicated E. coli Bacterial r-IL-1 (DP516) has been purified to homogeneity by anion exchange and sizing column chromatography, with an apparent molecular weight of 17,500. The identity of the purified r-IL-1 was confirmed by amino acid and DNA sequencing analyses. Purified recombinant IL-1 DP516 exhibits biological activity similar to that of native monocyte IL-1 (3 approximately 4 X 10(7) units/mg). An amino-terminal deletion mutant completely abolishes the biological activity, indicating that the integrity of the IL-1 molecule might be important for its function.

Amino Acid Sequence↗
PubMed1978

Lens structural disorders in the leopard frog (Rana pipiens) supplied to the laboratory from wild populations.

Examination of lenses of 48 leopard frogs, Rana pipiens, from three commercial suppliers disclosed a high incidence of histologic aberrations. Only four of 17 lenses that appeared totally clear under the dissecting microscope were found to be free of discernible abnormalities on histologic examination. Deviations were most common in the area of elongation. Because of these findings, the applicability of frog lenses for cellular investigations was questioned.

Animals↗
PubMed1976

Cellular changes in cultured lenses.

Observations were made on the frog lens epithelium after culture of the entire lens or of capsular explants. General deviations from normal lens structure as well as specific changes in two media were studied. DNA synthesis and mitosis were induced in the central epithelial cells. Disruption of the orderly, single, epithelial layer that is characteristic of normal lenses was accompanied by the appearance of multilayered plaques of epithelial cells and invasion of vacuolated regions of the lens fibers by epithelial cells. Cells that are fibroblast-like in appearance were observed in regions of the capsule depleted of cells and at the free edges of epithelial sheets in cell culture. Epithelial cells were surrounded by capsule-like material even situated in the lens interior. Nuclie derived from central epithelial cells of lenses cultured in L-15 medium and medium 199 had served as donors in previous nuclear transfer experiments in this laboratory. In our current observation of L-15-cultured lenses, cells were sparsely distributed on the capsule and nuclei were abnormally shaped; in 199-cultured lenses, cells were more densely distributed and nuclei resembled those of normal lenses. Medium 199 without serum could better maintain normal lens structure than L-15 medium without serum. In addition, the percentage of epithelial explants demonstrating cellular outgrowth was greater in medium 199. The differences in cellular behavior were shown not to be the result of different sugars, pH, or the presence of CO2. The nuclear transfer results may reflect the structural changes in the epithelium after lens culture in the two media.

Animals↗
PubMed1976

Cellular alterations accompany opacification in the cultured lens.

An examination of frog lenses cultured in specific serum-enriched medium was undertaken in order to determine whether such lenses could serve as in vitro models for studying the role of the lens epithelial cell. Histological analysis after sectioning of the lens revealed multilayered epithelial plaques and epithelial invasion of vacuolated cortical fibres, accompanied by the deposition of capsule-like material. A comparison of the effects of two media, L-15 and 199, indicated a greater incidence of opacification induced by L-15, which may be correlated with changes in lens epithelial cell nuclei.

Animals↗