Complex Ph1 translocation in chronic myeloid leukemia

This report describes a new case of chronic myeloid leukemia with an unusual Philadelphia chromosome translocation involving chromosomes No. 4,9, and 22; t(4,9,22) (q31;q34;q11).     

Retinoids and spermatogenesis: lessons from mutant mice lacking the plasma retinol binding protein.

Using Rbp4-null mice as models, we have established for the first time the kinetics of the spermatogenetic alterations during vitamin A deficiency (VAD). Our data demonstrate that the VAD-induced testicular degeneration arises through the normal maturation of germ cells in a context of spermatogonia differentiation arrest. They indicate that retinoic acid (RA) appears dispensable for the transition of premeiotic to meiotic spermatocytes, meiosis, and spermiogenesis. They confirm that RA plays critical roles in controlling spermatogonia differentiation, spermatid adhesion to Sertoli cells, and spermiation, and suggest that the VAD-induced arrest of spermatogonia differentiation results from simultaneous blocks in RA-dependent events mediated by RA receptor gamma (RARgamma) in spermatogonia and by RARalpha in Sertoli cells. They also provide evidence that expression of major RA-metabolizing enzymes is increased in mouse Sertoli cells upon VAD and that vitamin A-deficient A spermatogonia differ from their RA-sufficient counterparts by the expression of the Stra8 gene.     

Antifungal coating by biofunctionalized polyelectrolyte multilayered films

The surface of medical devices is a common site of bacterial and fungal adhesion, first step to the constitution of a resistant biofilm leading frequently to chronic infections. In order to prevent such complications, several physical and chemical modifications of the device surface have been proposed. Here, we experiment a new type of topical antifungal coating using the layer-by-layer technique. The nanometric multilayer film obtained by this technique is functionalized by the insertion of a chromogranin A-derived antifungal peptide (CGA 47-66, chromofungin). We show that the embedded peptide keeps its antifungal activity by interacting with the fungal membrane and penetrating into the cell. In vitro studies demonstrate that such an antifungal coating is able to inhibit the growth of yeast Candida albicans by 65% and completely stop the proliferation of filamentous fungus Neurospora crassa. The cytotoxicity of such a coating was also assessed by growing human gingival fibroblasts at its surface. Finally, the antifungal coating of poly(methylmethacrylate), a widely used material for biomedical devices, is successfully tested in an in vivo oral candidiasis rat model. Taken together, these results assessed the functionalized multilayer films containing a new potent antifungal non-toxic peptide, as a novel and promising technique for local antifungal protection.     

Evidence for a glycerol pathway through aquaporin 1 (CHIP28) channels

Permeabilities to glycerol and small non-electrolytes of three Aquaporin 1 CHIP (AQP1) water channels were measured in AQP1 cRNA-injected Xenopus laevis oocytes and in human AQP1 channels reconstituted in proteoliposomes. By an osmotic swelling assay, significant increases of ethylene glycol, glycerol and 1,3-propanediol apparent permeability coefficients (P_solutes) were found in oocytes expressing human, rat and frog AQP1. p-Chloromercuribenzene sulphonate (PCMBS) and CuSO₄ inhibited, by 95% and 58% respectively, apparent glycerol permeability (P _gly) in oocytes expressing human AQP1. pCMBS inhibition was reversed by -mercaptoethanol and CuSO₄ inhibition was partly reversed by the Cu²⁺-binding peptide Gly-Gly-His. Tritiated glycerol uptakes confirmed the augmented P _gly value of AQP1 cRNA-injected oocytes. In contrast, no increases of urea, meso-erythritol, D- or L-threitol, xylitol and mannitol uptakes were detected. Stopped-flow light scattering experiments performed with human AQP1 proteoliposomes also revealed a much greater increase of P _gly than did those with protein-free liposomes; the initial rate of proteoliposomes also swelling was inhibited by 96.2% with HgCl₂ and by 72.5% with CuSO₄. In AQP1 cRNA-injected oocytes and in proteoliposomes, the value of the glycerol reflection coefficient was 0.74–0.80, indicating that water and glycerol share the same pathway. All these results provide strong evidence that water and certain small solutes permeate the AQP1 channels expressed at the surface of X. laevis oocytes or reconstituted in proteoliposomes. The urea exclusion suggests that the selectivity of the AQP1 channels not only depends on the size of the solutes but probably also on their flexibility and their ability to form H-bonds.     

Distribution of Staphylococcus sciuri subspecies among human clinical specimens, and profile of antibiotic resistance

The distribution of three subspecies comprising Staphylococcus sciuri was determined for a collection of 30 clinical isolates originating from Morocco, the United Kingdom, and France. The sources of these isolates were principally wounds, skin, and soft tissue infections. At the species level, the isolates were identified according to biochemical characteristics and at the subspecies level by the ribotyping technique. PCR analysis performed with the 16S-23S ribosomal DNA intergenic spacer was less powerful for subspecies differentiation. S. sciuri subsp. sciuri was the most frequent subspecies (21 isolates) found in the collection, whereas S. sciuri subsp. rodentium (seven isolates) and S. sciuri subsp. carnaticus (two isolates) were less common. mecA or a mecA-related gene was detected by PCR and Southern blot in all 30 S. sciuri isolates, supporting the suggestion that S. sciuri species are the natural reservoir of the mecA gene. While the linA/linA' gene coding for lincomycin resistance was present in five isolates, an uncharacterized gene for this resistance was suspected in seventeen other isolates.     

The atheroprotective effect of 17beta-estradiol depends on complex interactions in adaptive immunity

Estradiol prevents fatty streak formation in chow-fed atherosclerosis-prone apolipoprotein E (ApoE)-deficient mice. We previously reported that fatty streak development of immunodeficient ApoE(-/-)/recombination activating gene 2 (RAG-2(-/-)) double-deficient mice was insensitive to estradiol. In the present work, we demonstrate that the reconstitution of ApoE(-/-)/RAG-2(-/-) with bone marrow from immunocompetent ApoE(-/-)/RAG-2(+/+) mice restores the protective effect of estradiol on fatty streak constitution. We extended this demonstration to the model of low-density lipoprotein receptor-deficient mice, establishing the obligatory role of mature lymphocytes in this process. We then investigated whether the protective effect of estradiol was mediated by a specific lymphocyte subpopulation by studying the hormonal effect on fatty streak constitution in recently developed models of ApoE(-/-) mice deficient in selective T-lymphocyte subsets (either TCRalphabeta+, CD4+, CD8+, or TCRgammadelta+ lymphocytes) or B lymphocytes. In all these specifically immunodeficient mice, estradiol administration to ovariectomized mice conferred protection as in immunocompetent ApoE(-/-) mice, clearly demonstrating that no single lymphocyte subpopulation was specifically required for this effect. These results point to additional lymphocyte-dependent mechanisms such as modulating the interactions among lymphocytes and between lymphocytes and endothelial and/or antigen-presenting cells.     

Detection of circulating Aspergillus fumigatus galactomannan: value and limits of the Platelia test for diagnosing invasive aspergillosis

The effectiveness of galactomannan detection with the Platelia test was evaluated in a prospective study of 3,327 sera from 807 patients. The specificity was 99.6% (748 of 751 cases). For the groups of patients with proven and probable invasive aspergillosis, the sensitivity was 50.0% (17 of 34 cases). The disappointing sensitivity associated with the presence of rare false-positive cases underlines the limits of this test.     

Prominent intrasinusoidal infiltration of the bone marrow by mantle cell lymphoma

Intrasinusoidal infiltration of bone marrow (BM) may accompany several malignant lymphoproliferative disorders. In small B-cell lymphomas, this pattern is considered specific for splenic marginal zone lymphoma (SMZL) when exclusive or prominent, although it may occur in other subtypes of non-Hodgkin's lymphomas (NHLs) as a minor feature. Here we report 2 cases of mantle cell lymphoma (MCL) with a prominent intrasinusoidal BM infiltration pattern. Both patients presented with massive splenomegaly and peripheral blood involvement characterized by markedly atypical lymphocytes, but no lymphadenopathy. The cytological features and the phenotype of the lymphoma cells were diagnostic of MCL. The malignant B cells showed coexpression of B-cell markers (CD20+ and CD79a+), CD5 antigen, and cyclin D1 by immunohistochemistry. We discuss the specificity of an intrasinusoidal growth pattern in the bone marrow, emphasizing the importance of using a broader immunohistochemical panel in the differential diagnosis of intrasinusoidal BM infiltration by NHL.     

Specific-impedance measurements of brain tissues

A technique that allowsin vivo measurements of the specific impedance of brain structures is analysed and implemented. This technique uses the 4-electrode method. The system includes an optically isolated current source and an interchangeable electrode module. Tests on the measuring system, including the electrodes and calibration procedures, are presented. Experiments in media of known resistivity and in cat brains define the present limits of the spatial resolution.