The HIV-1 Integrase Mutations Y143C/R Are an Alternative Pathway for Resistance to Raltegravir and Impact the Enzyme Functions

Resistance to HIV-1 integrase (IN) inhibitor raltegravir (RAL), is encoded by mutations in the IN region of the pol gene. The emergence of the N155H mutation was replaced by a pattern including the Y143R/C/H mutations in three patients with anti-HIV treatment failure. Cloning analysis of the IN gene showed an independent selection of the mutations at loci 155 and 143. Characterization of the phenotypic evolution showed that the switch from N155H to Y143C/R was linked to an increase in resistance to RAL. Wild-type (WT) IN and IN with mutations Y143C or Y143R were assayed in vitro in 3′end-processing, strand transfer and concerted integration assays. Activities of mutants were moderately impaired for 3′end-processing and severely affected for strand transfer. Concerted integration assay demonstrated a decrease in mutant activities using an uncleaved substrate. With 3′end-processing assay, IC₅₀ were 0.4 µM, 0.9 µM (FC = 2.25) and 1.2 µM (FC = 3) for WT, IN Y143C and IN Y143R, respectively. An FC of 2 was observed only for IN Y143R in the strand transfer assay. In concerted integration, integrases were less sensitive to RAL than in ST or 3′P but mutants were more resistant to RAL than WT.     

Cell types of the pars distalis of the hedgehog (Erinaceus europaeus L.) adenohypophysis: cytological, immunocytochemical and ultrastructural studies. 2. Prolactin cells

Staining and histochemical methods, immunofluorescence, and electron microscopy were used to individualize the prolactin cells in the adenohypophyseal pars distalis of the nonhibernating hedgehog. One cell type was differentiated; their characteristics at the light and electron microscopic levels were presented. Immunofluorescence has confirmed the functional significance of this cell type and the validity of the denomination 'prolactin cells'.     

Requirement for BSF-1 in the induction of antigen-specific B cell proliferation by a thymus-dependent antigen and carrier-reactive T cell line

We report here a role of B cell stimulatory factor 1 (BSF-1) in the induction of antigen-specific proliferation of affinity-purified small B lymphocytes by a thymus-dependent antigen and a carrier-reactive T cell line. By using an ovalbumin-reactive T cell line (designated Hen-1), which does not produce BSF-1 following activation, it was possible to demonstrate that the antigen-specific proliferative response of trinitrophenyl (TNP)-binding B cells to TNP-ovalbumin required exogenous BSF-1 in addition to direct interaction with irradiated Hen-1 T cells. The activation obtained under these conditions was highly efficient, being sensitive to antigen doses as low as 0.001 microgram/ml. The addition of saturating amounts of BSF-1 did not alter the antigen-specificity or the requirements for hapten-carrier linkage or major histocompatibility complex-restricted T-B interaction in this system. The involvement of BSF-1 was confirmed by the ability of 11B11 anti-BSF-1 antibody to specifically suppress the response of TNP-binding B cells to TNP-ovalbumin, BSF-1, and irradiated Hen-1 T cells. Finally, this response was augmented by addition of the monokine interleukin 1. These data indicate that the proliferative response of small B cells to the thymus-dependent antigen and carrier-reactive T cell line used in our experiments can be regulated by the same factors that govern B cell proliferation induced by thymus-independent type 2 antigens or anti-IgM antibodies.     

Correction of mouse ornithine transcarbamylase deficiency by gene transfer into the germ line

The sparse fur with abnormal skin and hair (Spf-ash) mouse is a model for the human X-linked hereditary disorder, ornithine transcarbamylase (OTC) deficiency. In Spf-ash mice, both OTC mRNA and enzyme activity are 5% of control values resulting in hyperammonemia, pronounced orotic aciduria and an abnormal phenotype characterized by growth retardation and sparse fur. Using microinjection, we introduced a construction containing rat OTC cDNA linked to the SV40 early promoter into fertilized eggs of Spf-ash mice. The expression of the transgene resulted in the development of a transgenic mouse whose phenotype and orotic acid excretion are fully normalized. Thus, the possibility of correcting hereditary enzymatic defect by gene transfer of heterologous cDNA coding for the normal enzyme has been demonstrated.     

Cell types of the pars distalis of the hedgehog (Erinaceus europaeus L.) adenohypophysis: cytological, immunocytochemical and ultrastructural studies. 4. Thyrotropic cells

Staining and histochemical methods, immunofluorescence and electron microscopy were used to individualize the thyrotropic cells in the adenohypophysis of the non-hibernating hedgehog. One cell type was differentiated; its characteristics at the light and electron-microscopic levels were presented. Immunofluorescence has confirmed the functional significance of this cell type and the validity of the denomination of 'thyrotropic cells'.     

Occurrence of a microcanalicular system within the ossicles and dermal tissue of Asterias rubens and Marthasterias glacialis (Echinodermata: Asteroidea)

Summary A microcanalicular network is demonstrated within the ossicle stroma and the dermal tissue of two asteroid species. Microcanaliculi are presumed to be mesodermal structures. They consist of convoluted tubular ducts lined by epithelial cells associated with scattered basiepithelial nervous processes. Such a microcanalicular system has not been reported previously from any echinoderm species. Its discovery in asteroids entails some conceptual changes, especially considering the physiology of the body wall.Research assistants of the National Fund for Scientific Research (NFSR, Belgium)