Isolation of a peptide inhibitor of human rhinovirus

Cell culture-based transdominant genetic techniques provide new methods for discovering peptide/RNA modulators of cellular pathways. We applied this technology to isolate a peptide inhibitor of human rhinovirus. A green fluorescent protein (GFP)-scaffolded library of cDNA fragments was expressed in HeLa cells from a retroviral vector and screened for inhibitors of rhinovirus-mediated cell killing. A DNA clone, I421, increased cell survival in an HRV14 challenge assay from less than 0.5% to greater than 60%. It encodes a 53-amino-acid C-terminal extension of the GFP scaffold. Particular subclones of Hela cells expressing I421 (exemplified by I421dp3) show a delay in virus production and a 50-fold decrease in viral RNA levels at 6-8 h postinfection. HRV2, HRV14, and HRV16 show a dramatic decrease in plaque-forming ability on I421dp3 while Coxsackievirus B3 showed a small reduction. Levels of ICAM-1, the receptor for the main rhinovirus serotype, are not altered in I421dp3.     

The effects of thermochemotherapy using cyclophosphamide plus hyperthermia on the malignant pleural mesothelioma in vivo

The human malignant pleural mesothelioma is related to the use of asbestos in the majority of cases. Though the use of asbestos has been prohibited since the 1990s, the incidence of pleural mesothelioma is still increasing because of a latency period of at least 20 years. This study investigated the benefit of single therapy with cyclophosphamide or hyperthermia or the combination of both on cells of a human pleural mesothelioma cell line, xenotransplanted subcutaneously in the paw of mice. A CONTROL group received the same volume of physiological saline. The oxygenation of tumours was measured, tumour growth was followed over 3 weeks, immunohistochemical studies and a light and electron microscopic evaluation were performed. Chemotherapy or hyperthermia alone was only temporarily effective. The greatest benefit was achieved using combined thermochemotherapy consisting of cyclophosphamide plus hyperthermia: 50% of this group had partial remissions, and 67% responded to this therapy. After 3 weeks tumours grew again. Superior effects could be achieved by performing additional cycles of chemotherapy or adding another drug or radiation for instance. This study shows promising results in the treatment of malignant pleural mesothelioma.     

Apoptotic cell death in mouse models of GM2 gangliosidosis and observations on human Tay-Sachs and Sandhoff diseases

Tay-Sachs and Sandhoff diseases are autosomal recessive neurodegenerative diseases resulting from the inability to catabolize GM2 ganglioside by beta-hexosaminidase A (Hex A) due to mutations of the alpha subunit (Tay-Sachs disease) or beta subunit (Sandhoff disease) of Hex A. Hex B (beta beta homodimer) is also defective in Sandhoff disease. We previously developed mouse models of both diseases and showed that Hexa-/- (Tay-Sachs) mice remain asymptomatic to at least 1 year of age while Hexb-/- (Sandhoff) mice succumb to a profound neurodegenerative disease by 4-6 months of age. Here we find that neuron death in Hexb-/- mice is associated with apoptosis occurring throughout the CNS, while Hexa-/- mice were minimally involved at the same age. Studies of autopsy samples of brain and spinal cord from human Tay-Sachs and Sandhoff diseases revealed apoptosis in both instances, in keeping with the severe expression of both diseases. We suggest that neuron death is caused by unscheduled apoptosis, implicating accumulated GM2 ganglioside or a derivative in triggering of the apoptotic cascade.      

Mechanisms of enhanced prevalence of asthma and atopy in developed countries

Atopy — a T helper 2 cell driven hypersensitivity to innocuous antigens (allergens) which causes most cases of asthma — is of complex genetic and environmental origins. There is compelling epidemiological evidence for a rise in atopic disease in ‘westernised’ communities. The changing pattern of microbial exposure in early childhood is suggested to be the principal candidate mechanism for this rise.     

Amplification of bovine papillomavirus DNA by N-methyl-N'-nitro-N-nitrosoguanidine, ultraviolet irradiation, or infection with herpes simplex virus

Treatment with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) or irradiation with ultraviolet light (uv254 nm) induces amplification of integrated as well as episomal sequences of bovine papillomavirus (BPV) type 1 DNA in BPV-1-transformed mouse C127 cells (i.e., ID13 cells). This is shown by filter in situ hybridization and Southern blot analysis of cellular DNA. Similarly, infection of ID13 cells with herpes simplex virus (HSV) type 1 which has been shown to be mutagenic for host cell DNA leads to amplification of BPV DNA sequences. In contrast to this induction of DNA amplification by initiators, treatment of ID13 cells with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) does not result in increased synthesis of BPV DNA nor does TPA treatment modulate the initiator-induced DNA amplification. Similar to other cell systems infection with adeno-associated virus (AAV) type 2 inhibits BPV-1 DNA amplification irrespective of the inducing agent. In contrast to initiator-induced DNA amplification, treatment with carcinogen (MNNG) or tumor promoters or combination of MNNG and promoter of C127 cells prior to transformation by BPV-1 does not lead to an increase in the number of transformed foci. The induction of amplification of papillomavirus DNA by initiating agents possibly represents one of the mechanisms by which the observed synergism between papillomavirus infection and initiators in tumorigenesis might occur.     

Preadsorption of polymers on glass and silica to reduce fibrinogen adsorption

Glass and silica beads were precoated with various polymers to obtain steric exclusion chromatography (SEC) supports which are nonadsorbant for hydrophilic macromolecules. The efficiency of this treatment was estimated by subsequent radiolabeled fibrinogen adsorption. The result obtained with a block copolymer was better than with various hydrophilic homopolymers. This ABA type block copolymer, where A is a poly(N-acetylethyleneimine) (PAEI) sequence and B a polyethylene oxide (PEO) sequence was preadsorbed at pH 4.5 and 25 degrees C; the fibrinogen adsorption was reduced to less than 5% of the value observed on untreated solid surfaces. Thus the hemocompatibility of solid supports should be increased by precoating with this block copolymer. Results for nonporous glass beads and porous silica particles were in good correlation.     

« FORSAFE » forceps et capteurs souples bio-inspirés

Living tissues are mainly constituted of soft matter. This so particular state, neither liquid, neither gas, nor solid led to the use, in simulation, of increasingly complicated mathematical models. These tissues are organised in multi-layers, present anisotropic properties and nonlinear behaviour. The evaluation of the interface pressure by traditional rigid sensors leads to errors of measurement. The device FORSAFE performs the measurement of the pressure on the fetal head. It is aimed to limit the risks due to a bad positioning and a too important tightening of the forceps on the head of the new-born, during the childbirth. It is based on an original method bio-inspired reproducing the sense of touch, by micro-palpations. Complications in forceps deliveries are rare but their consequences might be dramatics. This situation could be avoided if the obstetrician knows the information concerning symmetry of the obstetrical forceps position on the fetal head and the related interface pressure. Indeed, forceps delivery is an emergency gesture which is normally not expected. The aims of the FORSAFE device are: first, to prevent instrumented delivery accidents, secondly, to provide a safe training of forceps technique. This paper presents the original method of the interface pressure measurement, the results obtained on a physical model of interface pressure as well as the corrections performed on the probe placed on the forceps.     

Interleukin-12/T cell stimulating factor,a cytokine with multiple effects on T helper type 1 (Th1) but not on Th2 cells

At least two subsets of CD4⁺ T helper cell lymphocytes termed T_h1 and T _h, 2 exist in the mouse and probably in humans. They are characterized by the secretion of different lymphokines and by their functional behavior. Dysregulated expansion of one or the other subset may be one reason for the development of certain diseases. Thus, it is of importance to define the signals involved in the differentiation and activation of the two T_h cell subsets. It is known and has been confirmed in this report that the cytokine interleukin (IL)-1 acts onT_h2 cells but not on T_h1 cells. We now report that a previously identified cytokine which was provisionally termed T cell stimulating factor is identical with IL-12 and exhibits a reciprocal behaviour to IL-1. IL-12 has several effects on T_h1 cells. It can induce the proliferation of certain T_h1 cells in combination with IL-2. Synthesis of interferon (IFN)-γ by T_h1 cells can be triggered by IL-2 plus IL-12. In contrast to the IFN-γ production observed after T cell receptor (TcR) CD3 stimulation of T_h1 cells with lectin Concanavalin A the IFN-γ production induced by IL-12+IL-2 is insensitive to the immunosuppressive drug cyclosporin A. Furthermore, IL-12 enhances the TcR/CD3-induced synthesis of IFN-γ of several T_h1 clones. Finally, IL-12 (+ IL-2) induces homotypic cell aggregation of T_h1 clones. This type of cell aggregation depends on the participation of LFA-1 and ICAM-1 molecules. In all activation systems with T_h1 cells no effect of IL-1 was demonstrable. In contrast, only IL-1 but not IL-12 served as a co-stimulatory signal for several T_h2 cell lines activated via the TcR/CD3 complex.