Effects of Laser Bandwidth in Direct-Drive High-Performance DT-Layered Implosions on the OMEGA Laser.

In direct-drive inertial confinement fusion, the laser bandwidth reduces the laser imprinting seed of hydrodynamic instabilities. The impact of varying bandwidth on the performance of direct-drive DT-layered implosions was studied in targets with different hydrodynamic stability properties. The stability was controlled by changing the shell adiabat from (α_{F}≃5) (more stable) to (α_{F}≃3.5) (less stable). These experiments show that the performance of lower adiabat implosions improves considerably as the bandwidth is raised indicating that further bandwidth increases, beyond the current capabilities of OMEGA, would be greatly beneficial. These results suggest that the future generation of ultra-broadband lasers could enable achieving high convergence and possibly high gains in direct drive ICF.

Dynamics of photoinduced endosomal release of polyplexes.

Endosomal escape is a well-known bottleneck for successful delivery of macromolecular drugs and genes. Photochemical disruption of endosomal membranes is an approach to overcome this bottleneck. In this study, we used the photosensitizer disulphonated meso-tetraphenylporphine with sulfonate groups on adjacent phenyl rings (TPPS(2a)) to investigate photoinduced endosomal release in living cells with high resolution fluorescence wide-field microscopy in real time. We studied the release dynamics of 10 kDa dextran and polyplexes consisting of DNA condensed with the cationic polymers linear polyethyleneimine (LPEI), poly-(L)-lysine (PLL) or poly-(D)-lysine (PDL). By means of dual-color microscopy and the use of double-labeled polyplexes DNA and polymer were imaged simultaneously. We show that the characteristics of the cationic polymer significantly influence the release behavior of the polyplexes. The release of dextran occurred within 100 ms. For LPEI/DNA particles, LPEI quickly spread throughout the cytosol similar to dextran, whereas DNA was released slowly (within 4 s) and remained immobile thereafter. In case of PLL particles, both DNA and polymer showed quick release. PDL particles remained condensed upon photosensitizer activation. In addition, we demonstrate that TPPS(2a) has biological side effects. Besides stop of microtubule dynamics in the dark, the movement of endosomes ceased after photosensitizer activation.

Identification of immunological relevant phenotypes in ENU mutagenized mice.

The immunology screen focuses on the identification of novel gene products involved in the mammalian immune response and on the establishment of mouse models for immunological disorders. For this purpose, high throughput and semi-automated techniques were developed and optimized for low cost per sample and reproducibility. All assays are designed to be nonconsumptive and are based on peripheral blood or direct PCR amplification.

Comet assay as a tool to screen for mouse models with inherited radiation sensitivity.

Recent in vivo and in vitro data of patients analyzed for genetic susceptibility to radiation during cancer therapy have shown structural changes in the chromosomes to be prevalent both in the patients being treated and in their immediate family members. As structural changes in chromosomes frequently lead to activation of proto-oncogenes and elimination of tumor-suppressor genes, they represent important mechanisms for the initiation of DNA repair processes and tumorigenesis. With the exception of rare genetic syndromes such as AT (Ataxia telangiectasia) or NBS (Nijmegen Breakage Syndrome), the background for the inheritance of genetic susceptibility to radiation is unknown. Recently, a large-scale genetic screen of mouse mutants has been established within the German Human Genome Project (Hrabè de Angelis and Balling 1998). The goal of this ENU (ENU: ethylnitrosourea) mutagenesis screen is the generation of mutant mice that will serve as animal models for human diseases and genetic susceptibility. In order to fully utilize the potential of a genetic screen of this magnitude, in which exploration for genes responsible for genomic instability and radiation sensitivity is to occur, it is necessary to establish a simple assay system that is amenable to automation. Hence, we are using the single-cell gel electrophoresis (comet assay) to detect mouse mutants that display a genetic susceptibility to ionizing radiation. We have established the analysis parameters in the comet assay which are currently used to detect radiation-sensitive mouse mutants and to control the variance within the mouse population in the ENU screen. The assay can be used to isolate genes that are responsible for DNA repair and radiation sensitivity in mouse and human.

Mutation in the betaA3/A1-crystallin encoding gene Cryba1 causes a dominant cataract in the mouse.

During the mouse ENU mutagenesis screen, mice were tested for the occurrence of dominant cataracts. One particular mutant was discovered as a progressive opacity (Po). Heterozygotes show opacification of a superficial layer of the fetal nucleus, which progresses and finally forms a nuclear opacity. Since the homozygotes have already developed the total cataract at eye opening, the mode of inheritance is semidominant. Linkage analysis was performed using a set of genome-wide microsatellite markers. The mutation was mapped to chromosome 11 distal of the marker D11Mit242 (9.3 +/- 4.4 cM) and proximal to D11Mit36 (2.3 +/- 2.3 cM). This position makes the betaA3/A1-crystallin encoding gene Cryba1 an excellent candidate gene. Mouse Cryba1 was amplified from lens mRNA. Sequence analysis revealed a mutation of a T to an A at the second base of exon 6, leading to an exchange of Trp by Arg. Computer analysis predicts that the fourth Greek key motif of the affected betaA3/A1-crystallin will not be formed. Moreover, the mutation leads also to an additional splicing signal, to the skipping of the first 3 bp of exon 6, and finally to the deletion of the Trp residue. Both types of mRNA are present in the homozygous mutant lenses. The mutation will be referred to as Cryba1(po1). This particular mouse mutation provides an excellent animal model for a human congenital zonular cataract with suture opacities, which is caused by a mutation in the homologous gene.

Production and characterization of monoclonal antibodies against the hemolysin BL enterotoxin complex produced by Bacillus cereus.

A total of five hybridoma cell lines that produced monoclonal antibodies against the components of the hemolysin BL (HBL) enterotoxin complex and sphingomyelinase produced by Bacillus cereus were established and characterized. Monoclonal antibody 2A3 was specific for the B component, antibodies 1A12 and 8B12 were specific for the L(2) component, and antibody 1C2 was specific for the L(1) protein of the HBL enterotoxin complex. No cross-reactivity with other proteins produced by different strains of B. cereus was observed for monoclonal antibodies 2A3, 1A12, and 8B12, whereas antibody 1C2 cross-reacted with an uncharacterized protein of approximately 93 kDa and with a 39-kDa protein, which possibly represents one component of the nonhemolytic enterotoxin complex. Antibody 2A12 finally showed a distinct reactivity with B. cereus sphingomyelinase. The monoclonal antibodies developed in this study were also successfully applied in indirect enzyme immunoassays for the characterization of the enterotoxic activity of B. cereus strains. About 50% of the strains tested were capable of producing the HBL enterotoxin complex, and it could be demonstrated that all strains producing HBL were also highly cytotoxic.

[Bladder tumors: prognostic value of surface antigens and carcinoembryonic antigens. A retrospective study]. / Tumeurs de vessie: intérêt pronostique des antigènes de surface et de l'antigène carcino-embryonnaire. Etude rétrospective.

Seven patients presenting with recurrent diffuse, non-infiltrating tumors of the bladder were treated for several years by repeated endo-urethral resection, because radical exeresis was not possible. Each operative specimen was subjected to examination of the ABH blood-group antigens, pneumo-14 precursor, and carcino-embryonic antigens. The authors emphasize the prognostic interest of such studies.

Improvement of the demonstration of A, B, H surface antigens in bladder tumors by a simple immunofluorescence technique.

The presence of A, B and H blood group antigens in paraffin-embedded tissue sections was demonstrated with a routine direct and indirect immunofluorescence technique. Natural and human antisera were used for 102 biopsy specimens of the various blood groups, including normal mucosa and vesical tumors. This technique allows a more precise description than the specific red cell adherence reaction of the differentiation pattern of the tumor itself and of the surrounding and distant mucosa. It may prove useful in suggesting a revised classification system, with more diagnostic and prognostic significance.

[Blood group ABO (H) cell surface antigens in bladder tumours invading the chorion. Prognostic value of their determination by immunofluorescence. Retrospective study of one hundred and twenty-five cases]. / Les antigènes de groupe sanguin ABO (H), dans les tumeurs de vessie infiltrant le chorion. Valeur pronostique de leur détermination par immunofluorescence. Etude rétrospective de cent vingt-cinq cas.

The authors have studied 125 stage A bladder tumours with a follow-up period of at least 5 years. The ABH cell surface antigens were collected by a double-layer immunofluorescence technique which has already been described. All the cross sections were read by the same pathologist who knew nothing about the clinical developments. The results were divided into 3 groups : (I) all the tumour cells had retained their surface antigens. (II) Only some cells had retained surface antigens. (III) All cells were negative. Study of the development of the 3 groups shows that : in group I, all the patients (11) are alive 5 years later, and only one has presented with a lesion evolving towards infiltration. In group II (32 patients), only 38 p. cent of the patients are still living 5 years later, and 65 p. cent developed towards muscular infiltration. In group III (77 patients), 27 p. cent are alive after 5 years and 80 p. cent have developed towards muscular infiltration. Homogeneous retention of the surface antigens would therefore seem to be a favourable factor in the prognosis, even in the case of a tumour which has already infiltrated the chorion. The significance of the loss of surface antigens is less clear-cut, but is on the whole adverse. The significance would, however, probably be enhanced by study of the mucosa distal from the lesion, and by marking the substances which determine the blood groups.