Biomedical subjects

Hermann Katinger

Publications and source records attributed to Hermann Katinger.

76 records · Page 5Linked to original sources

PubMedDate not supplied

Specific effects of synthetic oligopeptides on cultured animal cells.

Synthetic oligopeptides, tri- to pentaglycine and tri- and tetraalanine, were found to enhance viable cell density and culture viability when applied at concentrations higher than milllimolar to the cultures of a model hybridoma line. Oligoalanines, in addition, enhanced monoclonal antibody yields. Oligoglycines promoted solely the cell growth, unless the batch culture was fed with a medium concentrate. Examination of the effects of various tripeptides composed of glycine, alanine, serine, threonine, lysine, and histidine showed that some of the peptides promoted the growth of the culture, while other peptides suppressed the growth and enhanced the monoclonal antibody yield. Determination of the levels of amino acids and peptides in culture media indicated that the observed changes of culture parameters were caused by intact peptide molecules, rather than by amino acids liberated from the peptides by enzymic cleavage.

Animals↗

PubMedDate not supplied

Enhancement of monoclonal antibody production by lysine-containing peptides.

In the search for peptides that could effectively enhance the monoclonal antibody production of a model hybridoma, the performance of five lysine-containing peptides was compared. The capacity of the peptides to enhance the monoclonal antibody yield correlated with their growth-suppressing activity. No correlation of the production-enhancing activity with the character of the distribution of cell-cycle phases could be found. All of the tested peptides, including the negative control peptide Gly-Phe-Gly, altered the cell-cycle phases distribution in favor of the proportion of the S phase. The peptides added to the hybridoma culture were found to be gradually decomposed into dipeptides and free amino acids. Among the set of tested lysine-containing di- to pentapeptides, the best results were obtained with the tripeptide Gly-Lys-Gly. The growth-suppressing and production-enhancing capacity of this peptide supplement was obviously associated with the temporary presence of the intact peptide molecule in the culture media, because the addition of a mixture of free amino acids constituting this peptide, i.e., glycine and lysine, displayed a different effect-a slight promotion of cell growth.

Animals↗

PubMedDate not supplied

Effect of increased expression of protein disulfide isomerase and heavy chain binding protein on antibody secretion in a recombinant CHO cell line.

Previous work has shown that a human-antibody-producing recombinant CHO cell line did not increase its intracellular content of protein disulfide isomerase (PDI) and heavy chain binding protein (BIP) according to the increasing expression of antibody. It was also found that the intracellular assembly of light and heavy chain is a major limiting factor for overall cell specific productivity, as secretion rates improve with higher light chain expression levels and heavy chain accumulates intracellularly when too little light chain is present. As these CHO cells had a significantly lower intracellular PDI content compared to that of hybridoma cells, these results have led us to try to overcome the limitation in the posttranslational assembly in the endoplasmatic reticulum. Recombinant CHO cells were transfected with PDI or BIP alone or in combination, and the effect on intracellular light and heavy chain content and specific production rate was determined. Overexpression of BIP, both alone and in combination with PDI, reduced the specific secretion rate, whereas PDI, when overexpressed alone, caused an increase of product secretion rate.

Animals↗

PubMedDate not supplied

Reepithelialization of experimental scalds effected by topically applied superoxide dismutase: controlled animal studies.

Highly reactive metabolites, such as oxygen free radicals, initiate a cascade of inflammatory processes in thermally damaged skin, leading to enhanced tissue loss and delayed wound healing. The extent of tissue necrosis in the zone of stasis is of prognostic significance in the wound healing process. In this study, the effect of oxygen free radical removal by recombinant human-Cu/Zn-superoxide dismutase, given in three different formulations during the inflammatory postburn phase and wound repair, was examined. Recombinant human superoxide dismutase was either injected directly into the lesions, spread as enzyme-containing gel onto the burned tissue, or encapsulated into liposomes consisting of 1,2 dipalmitoy-sn-glycero-3-phosphocholine, cholesterol and stearylamine, suspended into a hydrophilic gel and administered to burned animals immediately after trauma. Controls were treated with plain gel or kept untreated. Edema formation, size of lesions, deepening of necrosis, and reepithelialization were examined. Results indicate that superoxide dismutase treatment resulted in reduced and faster recruitment of edema formation, smaller wound sizes, and minor tissue necrosis compared to the controls, thus resulting in significantly faster reepithelialization after 3 weeks. These animal studies on the efficacy of liposomal oxygen free radical scavenger showed accelerated wound healing in all parameters tested.

Administration, Topical↗