The first measurements of soft x-ray flux from ignition scale Hohlraums at the National Ignition Facility using DANTE (invited)

The first 96 and 192 beam vacuum Hohlraum target experiments have been fielded at the National Ignition Facility demonstrating radiation temperatures up to 340 eV and fluxes of 20 TW/sr as viewed by DANTE representing an ～20?times flux increase over NOVA/Omega scale Hohlraums. The vacuum Hohlraums were irradiated with 2 ns square laser pulses with energies between 150 and 635 kJ. They produced nearly Planckian spectra with about 30±10% more flux than predicted by the preshot radiation hydrodynamic simulations. To validate these results, careful verification of all component calibrations, cable deconvolution, and software analysis routines has been conducted. In addition, a half Hohlraum experiment was conducted using a single 2 ns long axial quad with an irradiance of ～2×10(15)?W/cm(2) for comparison with NIF Early Light experiments completed in 2004. We have also completed a conversion efficiency test using a 128-beam nearly uniformly illuminated gold sphere with intensities kept low (at 1×10(14)?W/cm(2) over 5 ns) to avoid sensitivity to modeling uncertainties for nonlocal heat conduction and nonlinear absorption mechanisms, to compare with similar intensity, 3 ns OMEGA sphere results. The 2004 and 2009 NIF half-Hohlraums agreed to 10% in flux, but more importantly, the 2006 OMEGA Au Sphere, the 2009 NIF Au sphere, and the calculated Au conversion efficiency agree to ±5% in flux, which is estimated to be the absolute calibration accuracy of the DANTEs. Hence we conclude that the 30±10% higher than expected radiation fluxes from the 96 and 192 beam vacuum Hohlraums are attributable to differences in physics of the larger Hohlraums.     

Triple stimulus-responsive polypeptide nanoparticles that enhance intratumoral spatial distribution

To address the limited tumor penetration of nanoparticle drug delivery vehicles, we report the first pH-responsive polypeptide micelle that dissociates at the low extracellular pH of solid tumors. This histidine-rich elastin-like polypeptide block copolymer self-assembles at 37 °C into spherical micelles that are stabilized by Zn(2+) and are disrupted as the pH drops from 7.4 to 6.4. These pH-sensitive micelles demonstrate better in vivo penetration and distribution in tumors than a pH-insensitive control.     

Identification of the tissue inhibitor of metalloproteinases-2 (TIMP-2) binding site on the hemopexin carboxyl domain of human gelatinase A by site-directed mutagenesis. The hierarchical role in binding TIMP-2 of the unique cationic clusters of hemopexin modules III and IV

Cell surface activation of progelatinase A occurs in a quaternary complex with the tissue inhibitor of metalloproteinases-2 (TIMP-2) and two membrane-type matrix metalloproteinases. We have mutated the unique cationic clusters found in hemopexin modules III and IV of the carboxyl domain (C domain) of human gelatinase A to determine their role in binding TIMP-2. Twelve single, double, and triple site-directed mutations were produced that exhibited different TIMP-2 binding properties. Notably, single alanine substitutions at Lys547 and Lys617 reduced TIMP-2 binding by an order of magnitude from that of the recombinant wild-type C domain. Mutations that completely disrupted the C domain.TIMP-2 interaction were K558A/R561A, K610T/K617A, and K566A/K568A/K617A. A triple mutation, K566A/K568A/K575A, having TIMP-2 binding indistinguishable from the wild-type C domain (Kd 3.0 x 10(-8) M), showed that simple reduction of net positive charge does not reduce TIMP-2 affinity. Because the double mutation K566A/K568A also did not alter TIMP-2 binding, these data do not confirm previously reported chimera studies that indicated the importance of the triple lysine cluster at positions 566/567/568 in TIMP-2 binding. Nonetheless, a subtle role in TIMP-2 interaction for the 566/567/568-lysine triad is indicated from the enhanced reduction in TIMP-2 binding that occurs when mutations here were combined with K617A. Thus, these analyses indicate that the TIMP-2 binding surface lies at the junction of hemopexin modules III and IV on the peripheral rim of the gelatinase A C domain. This location implies that considerable molecular movement of the TIMP-2. C domain complex would be needed for the bound TIMP-2 to inhibit in cis the gelatinase A active site.     

Side chains that influence fidelity at the polymerase active site of Escherichia coli DNA polymerase I (Klenow fragment)

To investigate the interactions that determine DNA polymerase accuracy, we have measured the fidelity of 26 mutants with amino acid substitutions in the polymerase domain of a 3'-5'-exonuclease-deficient Klenow fragment. Most of these mutant polymerases synthesized DNA with an apparent fidelity similar to that of the wild-type control, suggesting that fidelity at the polymerase active site depends on highly specific enzyme-substrate interactions and is not easily perturbed. In addition to the previously studied Y766A mutator, four novel base substitution mutators were identified; they are R668A, R682A, E710A, and N845A. Each of these five mutator alleles results from substitution of a highly conserved amino acid side chain located on the exposed surface of the polymerase cleft near the polymerase active site. Analysis of base substitution errors at four template positions indicated that each of the five mutator polymerases has its own characteristic error specificity, suggesting that the Arg-668, Arg-682, Glu-710, Tyr-766, and Asn-845 side chains may contribute to polymerase fidelity in a variety of different ways. We separated the contributions of the nucleotide insertion and mismatch extension steps by using a novel fidelity assay that scores base substitution errors during synthesis to fill a single nucleotide gap (and hence does not require mismatch extension) and by measuring the rates of polymerase-catalyzed mismatch extension reactions. The R682A, E710A, Y766A, and N845A mutations cause decreased fidelity at the nucleotide insertion step, whereas R668A results in lower fidelity in both nucleotide insertion and mismatch extension. Relative to wild type, several Klenow fragment mutants showed substantially more discrimination against extension of a T.G mismatch under the conditions of the fidelity assay, providing one explanation for the anti-mutator phenotypes of mutants such as R754A and Q849A.     

Composite B-cell and T-cell lymphoma arising 24 years after nodular lymphocyte predominant Hodgkin''s disease

Surfactant protein A (SP-A) is the major protein of pulmonary surfactant. This protein is implicated in regulating surfactant secretion, alveolar processing, recycling, and in non-serum-induced immune response. An increasing body of work indicates the importance of cations, particularly calcium, on SP-A function. However, little information exists on the effects of cations on SP-A quaternary structure. Here, the quaternary organisation of bovine surfactant protein A in the presence of cations has been quantitatively and systematically studied by transmission electron microscopy. The conformation of SP-A is altered by the presence of cations, especially calcium, then sodium, and to a small extent, magnesium. There is a transition concentration, unique for each cation, at which a conformational switch occurs. These transition concentrations are: 5 mM for CaCl2, 100 mM for NaCl and 1 mM for MgCl2. Below these concentrations, SP-A exists primarily in an opened form with a large head diameter of 20 nm; above it, SP-A is mostly in a closed form due to a compaction of the headgroups resulting in a head diameter of 11 nm. There is a corresponding increase in particle length from 17 nm for opened SP-A to 20 nm for closed SP-A. The fact that the transition concentrations are within physiological range suggests that cation-mediated conformational changes of SP-A could be operative in vivo.     

Evaluation of enterolithiasis in equids: 900 cases (1973-1996)

In this study we investigated the effect of lesioning the noradrenergic systems on the behavioral effects of (5R, 10S)-(+)-5-Methyl-10,11-dihydro-5H-dibenzo [a, d] cyclohepten-5,10-imine hydrogen maleate--MK-801, in rats. The noradrenergic system was lesioned with N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine hydrochloride--DSP4 (60 mg/kg IP). MK-801 increased the locomotor activity and rearing. DSP4 significantly further increased the hyperlocomotor activity, circling (especially to the left side), sniffing, rolling, and falling that were induced by MK-801. These results showed that destruction of the noradrenergic system increased MK-801-hyperlocomotor activity, ataxia and stereotypy.     

Identification of a calcium binding site in Staphylococcus hyicus lipase: generation of calcium-independent variants

OBJECTIVES: To evaluate the effectiveness and morbidity of salvage brachytherapy for locally recurrent or persistent prostate cancer after radiotherapy failure. METHODS: In this retrospective study, 49 patients of median age 73.3 years (range 52.9 to 86.9) with biopsy-proven localized prostate cancer underwent interactive transperineal fluoroscopic-guided and biplane ultrasound-guided brachytherapy with either iodine 125 or palladium 103 after prior radiotherapy failure. Post-treatment follow-up was conducted for a median of 64.1 months (range 26.6 to 96.8) and included clinical assessment of disease status, assays of serum prostate-specific antigen (PSA) levels, and documentation of treatment-related symptoms and complications. Determination of biochemical treatment failure was based on two successive rising PSA values above the post-treatment PSA nadir value. RESULTS: The actuarial rate of local prostate cancer control was 98% (95% confidence interval [CI] 94% to 99%). Actuarial disease-specific survival at 3 and 5 years was 89% (95% CI 73% to 96%) and 79% (95% CI 58% to 91%), respectively. At 3 and 5 years, actuarial biochemical disease-free survival was 48% (95% CI 32% to 63%) and 34% (95% CI 17% to 51%), respectively. Post-treatment PSA nadir was found to be a significant predictor of biochemical disease-free survival. Actuarial biochemical disease-free survival of patients who achieved a PSA nadir less than 0.5 ng/mL was 77% (95% CI 53% to 90%) and 56% (95% CI 25% to 78%) at 3 and 5 years, respectively. Of 49 patients, 23 (47%) achieved a post-treatment PSA nadir less than 0.5 ng/mL. The incidence of serious complications after salvage brachytherapy, such as incontinence and rectal complications, was lower than that reported after other types of salvage procedures. CONCLUSIONS: Interactive transperineal fluoroscopic-guided and biplane ultrasound-guided brachytherapy is a novel, potentially curative salvage modality for patients in whom prior radiotherapy failed. In a population of patients with poor prognosis, this modality was associated with a high rate of local prostate cancer control and a 34% actuarial rate of biochemical disease-free survival at 5 years. The incidence of major complications after salvage brachytherapy appears to be lower than that after other potentially curative salvage procedures, such as radical prostatectomy and cryoablation. Salvage brachytherapy warrants further investigation.