Biomedical subjects

D J Sarubbi

Publications and source records attributed to D J Sarubbi.

2 recordsLinked to original sources

PubMed1990

Evaluation of the role of extracellular matrix proteins, polyunsaturated fatty acids and c-myc expression in the inhibition of the serum-free growth of epithelial cells by TGF-beta 1.

Novel or modified serum-free media were developed for the anchorage-dependent growth of nontransformed murine mammary epithelial cells (MMEC) and Balb/MK murine keratinocytes respectively. Growth rates for both cell lines were similar in serum-containing and serum-free media. The serum-free media were used to evaluate potential mechanisms of epithelial cell growth regulation by type 1 transforming growth factor beta (TGF-beta 1). The growth of MMEC and Balb/MK cells was reversibly inhibited 40-65% in a time- and dose-dependent fashion by TGF-beta 1 under both serum-containing and serum-free conditions. Constitutive over-expression of a transfected c-myc oncogene in MMEC did not result in loss of sensitivity to growth inhibition by TGF-beta 1. In addition, Balb/MK and MMEC growth inhibition by TGF-beta 1 was not potentiated by polyunsaturated fatty acids or reversed by vitamin E. Exogenous type V collagen was able to mimic the inhibitory effects of TGF-beta 1 on the serum-free growth of Balb/MK and MMEC. In contrast, collagen types I and IV, fibronectin and laminin did not inhibit the growth of these cells. The type V collagen used was not contaminated with TGF-beta, and subsaturating, but not saturating concentrations of type V collagen and TGF-beta 1 were additive with respect to Balb/MK and MMEC growth inhibition. These results demonstrate that nontransformed epithelial cell growth inhibition by TGF-beta 1 is mediated by mechanisms distinct from those observed with certain carcinoma and melanoma cells. Our results also suggest the possible involvement of type V collagen in Balb/MK and MMEC growth inhibition by TGF-beta 1.

Animals↗

PubMedDate not supplied

pH-dependent microspheres from modified soybean protein hydrolysate.

Soybean hydrolysate is a hydrophilic mixture of amino acids and low molecular peptides which are soluble over the whole pH range. Chemical modification of soybean hydrolysate with aromatic acyl chlorides resulted in a product that yielded pH-dependent microspheres. Investigation into the physiochemical properties of the microsphere forming material indicated that acylation had alerted the hydrophobic/hydrophilic ratio as evidenced by an increased column retention time on reverse phase HPLC. This was further confirmed by analysis of the amino acid composition of the modified material. The data indicated that the hydrophobic/hydrophilic ratio and low molecular were critical factors in the formation of this supramolecular complex. An estimation based on sedimentation rate revealed an average molecular weight of these microspheres as 10(7)-10(8) Daltons. Light scattering experiments indicated that the microspheres have discrete chambers in the interior. Included among the properties of the microspheres that have been determined are the pH range of the phase transition, size distribution and zeta-potential. The physiochemical characteristics of the microspheres prepared from modified soybean protein are similar to the microsphere forming material produced by thermal condensation of amino acids. Formation of microspheres in solution containing either porcine insulin or salmon calcitonin resulted in the encapsulation of nearly 60% of the dissolved proteins. Oral gavage of encapsulated porcine insulin or salmon calcitonin into the stomach of rats resulted in significant titers of either protein in the systematic circulation.

Amino Acids↗