A Simple Survival Model for Combined Action of Two Damaging Agents

The aim of this study was mathematical formalization of the development of two damage processes in response to the combined action of two different damaging agents. The model allows to obtain the parametric family of distributions for the life-span when the organism's death is due to joint effect of two damage processes. Differing by their probabilistic meaning the notions of a priori (M (t)) and a posteriori (M(y)) conditional mean contributions of each damage process to the final effect of combined injury are introduced. The formulas permitting to compute the M and M values on the basis of survival data parametric analysis are given.     

Identification of the proteins in direct contact with duck globin mRNA

Proteins in direct contact with translationally active and repressed duck globin mRNA were determined by irradiating blood or lysates with ultraviolet light. Cross-linked proteins from polyribosomes and free mRNP particles were 14C-labeled by reductive methylation and identified on SDS-polyacrylamide gels upon autoradiography. Results indicate that ten cross-linked proteins are common to both polysomal and free mRNP, however, a 44 kDa protein appears to be specific for repressed mRNP particles. Furthermore, the notable lack of cross-linked proteins in the 20-30 kDa range in free mRNP supports the view that the characteristic low molecular mass 'prosomal' proteins, previously found associated with translationally repressed duck globin free mRNP [(1984) EMBO J. 3, 29-34], do not interact directly with the mRNA molecule.     

Expression of antiviral activity and induction of 2',5'-oligoadenylate synthetase by conceptus secretory proteins enriched in bovine trophoblast protein-1

Establishment of pregnancy in cattle has been proposed to depend on production of a conceptus protein, bovine trophoblast protein-1 (bTP-1), which has a high degree of sequence homology with bovine interferon-alpha (bIFN-alpha), especially the alpha II subfamily. A preparation of bovine conceptus secretory proteins enriched for bTP-1 has antiviral and physico-chemical properties similar to other bIFN-alpha. Antiviral activity is initially detectable in uterine flushings on Day 14 of pregnancy, when the conceptus measures 4-5 mm in length, and increases as the conceptus elongates through Day 18. Day 17 conceptuses produce more than 10(6) U antiviral activity during 24 h of culture. All IFNs induce the enzyme 2',5'-oligoadenylate synthetase, which catalyzes production of 2',5'-oligo(A), which in turn is involved in antiviral and growth inhibitory effects of IFNs. This enzyme activity is induced in Madin-Darby bovine kidney cells by the partially purified bTP-1 preparation similarly to IFN-alpha, -beta, and -gamma. Likewise, the partially purified bTP-1 and bIFN-alpha 1 induce 2',5'-oligo(A) synthetase activity in monolayers of endometrial epithelial and stromal cells. Compared to epithelial cells, stromal cells have higher baseline activity of 2'-5'-oligo(A) synthetase activity (p less than 0.01) and show a greater degree of induction in the presence of either the partially purified bTP-1 or bIFN-alpha 1 (p less than 0.01). Also, 2',5'-oligo(A) synthetase of endometrial stromal cells is induced to a greater degree by our enriched bTP-1 preparation than by bIFN-alpha 1 (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)