Carcinoembryonic antigen (CEA) in non digestive cancerous and normal tissues.

Carcinoembryonic antigen (CEA), immunologically identical to CEA derived from colonic carcinoma, was identified and purified from perchloric acid (PCA) extracts of bronchial and mammary carcinoma. CEA extracted from bronchial and mammary carcinoma was quantitated by single radial immunodiffusion and was found to be in average about 50-75 times less abundant in these tumors than in colonic carcinoma. CEA could also be detected in one normal breast in lactation and at lower concentrations in normal lung (1000-4000 times lower than in colonic carcinoma). The small amounts of CEA present in normal tissues are distinct from the glycoprotein of small mol. wt showing only partial identity with CEA, that we recently identified and extracted in much larger quantities from normal lung and spleen. The demonstration of the presence of CEA in non digestive carcinoma by classical gel precipitation analysis suggests that the CEA detected in the plasma of such patients by radioimmunoassay is also identical to colonic carcinoma CEA. Our comparative study of plasma CEA from bronchial and colonic carcinoma, showing that CEA from both types of patient has the same elution pattern on Sephadex G-200 and gives parallel inhibition curves in the radioimmunoassay, is in favor of this hypothesis. However, it should not be concluded that all positive CEA radioimmunoassay indicate the presence of an antigen identical to colonic carcinoma CEA. A word of warning concerning the interpretation of radioimmunoassay is required by the observation that the addition of mg amounts of PCA extract of normal plasma, cleared of CEA by Sephadex filtration, could interfere in the test and mimic the presence of CEA.

Expression of the alpha 1b-adrenergic receptor and G protein subunits in mammalian cell lines using the Semliki Forest virus expression system.

Semliki Forest virus (SFV) vectors have been efficiently used for rapid high level expression of several G protein-coupled receptors. Here we describe the use of SFV vectors to express the alpha 1b-adrenergic receptor (AR) alone or in the presence of the G protein alpha q and/or beta 2 and gamma 2 subunits. Infection of baby hamster kidney (BHK) cells with recombinant SFV-alpha 1b-AR particles resulted in high specific binding activity of the alpha 1b-AR (24 pmol receptor/mg protein). Time-course studies indicated that the highest level of receptor expression was obtained 30 hours post-infection. The stimulation of BHK cells, with epinephrine led to a 5-fold increase in inositol phosphate (IP) accumulation, confirming the functional coupling of the receptor to G protein-mediated activation of phospholipase C. The SFV expression system represents a rapid and reproducible system to study the pharmacological properties and interactions of G protein coupled receptors and of G protein subunits.

Effects of selection and drift on G matrix evolution in a heterogeneous environment: a multivariate Qst-Fst Test with the freshwater snail Galba truncatula.

Unraveling the effect of selection vs. drift on the evolution of quantitative traits is commonly achieved by one of two methods. Either one contrasts population differentiation estimates for genetic markers and quantitative traits (the Q(st)-F(st) contrast) or multivariate methods are used to study the covariance between sets of traits. In particular, many studies have focused on the genetic variance-covariance matrix (the G matrix). However, both drift and selection can cause changes in G. To understand their joint effects, we recently combined the two methods into a single test (accompanying article by Martin et al.), which we apply here to a network of 16 natural populations of the freshwater snail Galba truncatula. Using this new neutrality test, extended to hierarchical population structures, we studied the multivariate equivalent of the Q(st)-F(st) contrast for several life-history traits of G. truncatula. We found strong evidence of selection acting on multivariate phenotypes. Selection was homogeneous among populations within each habitat and heterogeneous between habitats. We found that the G matrices were relatively stable within each habitat, with proportionality between the among-populations (D) and the within-populations (G) covariance matrices. The effect of habitat heterogeneity is to break this proportionality because of selection for habitat-dependent optima. Individual-based simulations mimicking our empirical system confirmed that these patterns are expected under the selective regime inferred. We show that homogenizing selection can mimic some effect of drift on the G matrix (G and D almost proportional), but that incorporating information from molecular markers (multivariate Q(st)-F(st)) allows disentangling the two effects.

Demyelination in brain cell aggregate cultures, induced by a monoclonal antibody against the myelin/oligodendrocyte glycoprotein (MOG).

Previous work has shown that aggregate cultures prepared from fetal rat telencephalon and grown in a chemically defined medium offer a useful model to study developmental processes such as myelin synthesis. Since compact myelin is formed in these cultures, we investigated the possibility to use this culture system to study demyelinating mechanisms. In particular, we examined the effect of a monoclonal antibody (8-18C5) directed against the myelin/oligodendrocyte glycoprotein (MOG). We found that addition of anti-MOG antibodies and complement to aggregate cultures led to a highly significant decrease in myelin basic protein (MBP) content and 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) specific activity. These results indicate that, in our culture system, anti-MOG antibodies have a strong demyelinating effect.

Evaluation of the anti-arenaviral activity of the subtilisin kexin isozyme-1/site-1 protease inhibitor PF-429242.

The cellular protease subtilisin kexin isozyme-1 (SKI-1)/site-1 protease (S1P) is implicated in the proteolytic processing of the viral envelope glycoprotein precursor (GPC) of arenaviruses, a step strictly required for production of infectious progeny. The small molecule SKI-1/S1P inhibitor PF-429242 was shown to have anti-viral activity against Old World arenaviruses. Here we extended these studies and show that PF-429242 also inhibits GPC processing and productive infection of New World arenaviruses, making PF-429242 a broadly active anti-arenaviral drug. In combination therapy, PF-429242 potentiated the anti-viral activity of ribavirin, indicating a synergism between the two drugs. A hallmark of arenaviruses is their ability to establish persistent infection in vitro and in vivo. Notably, PF-429242 was able to efficiently and rapidly clear persistent infection by arenaviruses. Interruption of drug treatment did not result in re-emergence of infection, indicating that PF-429242 treatment leads to virus extinction.