Immunosuppressive factors from human breast carcinoma cell lines that affect initiation of lymphocyte proliferation

Summary Supernatants from two human breast carcinoma cell lines, 734B and 231, have been shown to inhibit lymphocyte activation by mitogens and antigens. This inhibition appears to be specific for lymphocytes or recently stimulated cells, while having no effect on the growth of established cell lines. Studies of the mechanism of inhibition revealed that the factors inhibit lymphocyte activation and that the factors must be present at the initiation of lymphocyte stimulation for inhibition to occur. The supernatants do not inhibit lymphocyte activation by blocking binding of PHA to lymphocytes. Preliminary purification steps have shown that the inhibitory factors present in the tissue culture supernatants are precipitated at 50% ammonium sulfate saturation and their molecular weights are greater than 100 000. The inhibitory capacity of the 734B supernatants was destroyed by heating at 70° C, while the factors present in the 231 supernatants were only partially destroyed by heating to 90° C. The possible mechanism of action of the inhibitory substances released by tumors and their relevance to tumor growth are important to understanding of immune responses to neoplasia.     

Equilibria of the anomeric and ring forms of ammonium 3-deoxy-d-manno-octulosonate in deuterium oxide

The tautomeric composition of a solution of ammonium 3-deoxy-d-manno-octulosonate (KDO, 1a) in D₂O at 28° was assessed by means of ¹³ C-F.t.-n.m.r. spectroscopy. The results revealed the presence of 6?0 and 11 % of the α and β anomers of the pyranose, and 20 and 9 % of the two furanoses, and suggested, but did not unequivocally prove, that the major furanose form is the α anomer. To facilitate interpretation of the spectral results for 1, ammonium 3,5-dideoxy-d-arabino(or ribo)-octulosonate (3a) was prepared by the reaction of 5-deoxy-d-erythro-pentose with sodium oxalacetate at pH 11. A chromatographically homogeneous, noncrystalline sample of 3 was obtained by lyophilization, and characterized as its (4-nitrophenyl)hydrazone (m.p. 162-163°). The ¹³C-n.m.r. spectrum of a solution of 3a in D₂O revealed it to be substantially all in the α-pyranose form. No signals were obtained for the possible 1,4-lactone of 3. As the 1,5-lactone and furanose forms are impossible for 3, it exhibited no signals analogous to those attributed to furanoid 1. On the basis of these results for 3, the two lactone forms of 1 were excluded from consideration, and the three pairs of ¹³C-n.m.r. signals observed at ≈45, 86, and 104 p.p.m. were assigned to the furanose forms of 1.     

A comparative cytopathologic study of noninvasive and invasive squamous cell carcinoma of the lung

Atypical cells and tissue fragments from the sputum of patients with early and advanced stages of squamous cell carcinoma of the bronchus are objectively characterized and quantitatively compared in this paper. Four classes of single-cell features of cytoplasm, nucleus, nucleolus and nuclear-cytoplasmic ratio are analyzed as a function of cell size and tumor development stage. Distinct differences in the cellular patterns are observed which may enhance cytologic discrimination between noninvasive and invasive stages of squamous cell carcinoma of the bronchus. Initial results justify the application of more sensitive measurement techniques (i.e., automated cytology) to an enlarged data base.     

Interaction of DNA with a porphyrin ligand: evidence for intercalation.

The porphyrin photosensitizer, meso-Tetra (4-N-methylpyridyl) porphine tetraperchlorate binds to calf thymus DNA by intercalation and by external electrostatic association. This was concluded from the results of measruements involving Scatchard analysis, viscometry, thermal denaturation, and circular dichroism.     

Interferon Treatment of Ehrlich Ascites Tumor Cells: Effects on Exogenous mRNA Translation and tRNA Inactivation in the Cell Extract

We reported earlier that in cell extracts that were prepared from interferon-treated Ehrlich ascites tumor cells and preincubated and passed through Sephadex G-25 (S30_INT), the translation of exogenous mRNA (viral and host) was impaired and the impairment could be overcome to a large extent by adding a crude tRNA preparation from Ehrlich ascites tumor cells but not from Escherichia coli. We find now that the rate of inactivation of some tRNA's (especially those specific for leucine, lysine, and serine) but not those of many others is faster in S30_INT than in corresponding extracts from control cells. This increased rate of tRNA inactivation may perhaps account for the need for added RNA to overcome at least partially the impairment of translation in S30_INT. The relationship of the increased rate of tRNA inactivation to the antiviral effect of interferon is unclear. So far no significant difference has been detected in the amount of tRNA needed to overcome the impairment of encephalomyocarditis virus RNA translation in S30_INT between tRNA from interferon-treated cells and tRNA from control cells. Furthermore, no difference was found in the rate of inactivation in S30_INT between leucine-specific tRNA's from interferon-treated and from control cells. tRNA's specific for leucine and lysine were not inactivated (unless very slowly) during incubation under our conditions in an extract from interferon-treated (or from control) cells unless the extract had been passed through Sephadex G-25 or dialyzed. The translation of exogenous mRNA was, however, impaired in an extract from interferon-treated cells that had not been passed through Sephadex G-25. This impairment was apparently not overcome by added tRNA.     

Synthesis and degradation of proteins during wheat endosperm development

Synthesis of proteins rich in lysine declines progressively with endosperm development and these proteins appear to be degraded preferentially at later stages. The proteolytic enzymes in extracts of endosperms at a late stage of development release considerably more lysine radioactivity from labelled endosperm proteins as compared with the enzymes in endosperms at an early stage.     

An interactive nonrandom-mating two-sex model whose intrinsic growth rate lies between one-sex rates.

In a recent paper, the author has presented an interactive two-sex model and applied it to the U.S. population, 1940–1971. While the model has removed many inconsistencies in the one-sex models for males and females, it has two major limitations. First, the model assumes random mating of men and women within their reproductive ages. Second, it gives an intrinsic growth rate that is not necessarily intermediate between the male and the female intrinsic growth rates, as obtained from the one-sex models. A new two-sex model is provided in this paper that removes both these limitations. The new model is applied to the U.S. population for the years 1940–1974.