Guidelines of the Design of Electropyrotechnic Firing Circuit for Unmanned Flight and Ground Test Projects

The NASA Langley Research Center, Engineering Directorate, Electronic System Branch, is responsible for providing pyrotechnic support capabilities to Langley Research Center unmanned flight and ground test projects. These capabilities include device selection, procurement, testing, problem solving, firing system design, fabrication and testing; ground support equipment design, fabrication and testing; checkout procedures and procedure?s training to pyro technicians. This technical memorandum will serve as a guideline for the design, fabrication and testing of electropyrotechnic firing systems. The guidelines will discuss the entire process beginning with requirements definition and ending with development and execution

D₂ Dopamine Receptors Colocalize Regulator of G-Protein Signaling 9-2 (RGS9-2) via the RGS9 DEP Domain, and RGS9 Knock-Out Mice Develop Dyskinesias Associated with Dopamine Pathways

Regulator of G-protein signaling 9-2 (RGS9-2), a member of the RGS family of Gα GTPase accelerating proteins, is expressed specifically in the striatum, which participates in antipsychotic-induced tardive dyskinesia and in levodopa-induced dyskinesia. We report that RGS9 knock-out mice develop abnormal involuntary movements when inhibition of dopaminergic transmission is followed by activation of D₂-like dopamine receptors (DRs). These abnormal movements resemble drug-induced dyskinesia more closely than other rodent models. Recordings from striatal neurons of these mice establish that activation of D₂-like DRs abnormally inhibits glutamate-elicited currents. We show that RGS9-2, via its DEP domain (for Disheveled, EGL-10, Pleckstrin homology), colocalizes with D₂DRs when coexpressed in mammalian cells. Recordings from oocytes coexpressing D₂DR or the m2 muscarinic receptor and G-protein-gated inward rectifier potassium channels show that RGS9-2, via its DEP domain, preferentially accelerates the termination of D₂DR signals. Thus, alterations in RGS9-2 may be a key factor in the pathway leading from D₂DRs to the side effects associated with the treatment both of psychoses and Parkinson's disease

New Insight into Filamentous Hemagglutinin Secretion Reveals a Role for Full-Length FhaB in Bordetella Virulence

ABSTRACTBordetella filamentous hemagglutinin (FHA), a primary component of acellular pertussis vaccines, contributes to virulence, but how it functions mechanistically is unclear. FHA is first synthesized as an ~370-kDa preproprotein called FhaB. Removal of an N-terminal signal peptide and a large C-terminal prodomain (PD) during secretion results in “mature” ~250-kDa FHA, which has been assumed to be the biologically active form of the protein. Deletion of two C-terminal subdomains of FhaB did not affect production of functional FHA, and the mutant strains were indistinguishable from wild-type bacteria for their ability to adhere to the lower respiratory tract and to suppress inflammation in the lungs of mice. However, the mutant strains, which produced altered FhaB molecules, were eliminated from the lower respiratory tract much faster than wild-type B.bronchiseptica, suggesting a defect in resistance to early immune-mediated clearance. Our results revealed, unexpectedly, that full-length FhaB plays a critical role in B.bronchiseptica persistence in the lower respiratory tract.IMPORTANCEThe Bordetella filamentous hemagglutinin (FHA) is a primary component of the acellular pertussis vaccine and an important virulence factor. FHA is initially produced as a large protein that is processed during secretion to the bacterial surface. As with most processed proteins, the mature form of FHA has been assumed to be the functional form of the protein. However, our results indicate that the full-length form plays an essential role in virulence in vivo. Furthermore, we have found that FHA contains intramolecular regulators of processing and that this control of processing is integral to its virulence activities. This report highlights the advantage of studying protein maturation and function simultaneously, as a role for the full-length form of FHA was evident only from in vivo infection studies and not from in vitro studies on the production or maturation of FHA or even from in vitro virulence-associated activity assays

Cooperative Roles for Fimbria and Filamentous Hemagglutinin in Bordetella Adherence and Immune Modulation

ABSTRACTBordetella fimbriae (FIM) are generally considered to function as adhesins despite a lack of experimental evidence supporting this conclusion for Bordetella pertussis and evidence against a requirement for FIM in adherence of Bordetella bronchiseptica to mammalian cell lines. Using B.bronchiseptica and mice, we developed an in vivo adherence assay that revealed that FIM do function as critically important adhesins in the lower respiratory tract. In the first few days postinoculation, FIM-deficient B.bronchiseptica induced a more robust inflammatory response than wild-type bacteria did, suggesting that FIM, like filamentous hemagglutinin (FHA), allow B.bronchiseptica to suppress the innate immune response to infection. Localization analyses indicated that FIM are required for efficient attachment to airway epithelium, as bacteria lacking FIM localized to alveoli. FHA-deficient bacteria, in contrast, localized to airways. Bacteria unable to produce both FIM and FHA localized to alveoli and caused increased inflammation and histopathology identical to that caused by FIM-deficient bacteria, demonstrating that lack of FIM is epistatic to lack of FHA. Coinoculation experiments provided evidence that wild-type B.bronchiseptica suppresses inflammation locally within the respiratory tract and that both FHA and FIM are required for defense against clearance by the innate immune system. Altogether, our data suggest that FIM-mediated adherence to airway epithelium is a critical first step in Bordetella infection that allows FHA-dependent interactions to mediate tight adherence, suppression of inflammation, and resistance to inflammatory cell-mediated clearance. Our results suggest that mucosal antibodies capable of blocking FIM-mediated interactions could prevent bacterial colonization of the lower respiratory tract.IMPORTANCEAlthough fimbriae (FIM) have been shown to be important mediators of adherence for many bacterial pathogens, there is surprisingly little experimental evidence supporting this role for Bordetella fimbria. Our results provide the first demonstration that Bordetella FIM function as adhesins in vivo, specifically to airway epithelium. Furthermore, our results suggest that FIM mediate initial interactions with airway epithelial cells that are followed by tight filamentous hemagglutinin (FHA)-mediated binding and that together, FIM and FHA allow Bordetella to suppress inflammation, leading to prolonged colonization. Given the shortcoming of the current acellular component pertussis (aP) vaccine in preventing colonization, these findings suggest that generation of antibodies capable of blocking FIM-mediated adherence could potentially prevent Bordetella colonization

Bordetella pertussis pathogenesis: current and future challenges

Pertussis, or whooping cough, has recently reemerged as a major public health threat despite high levels of vaccination against the etiological agent, Bordetella pertussis. In this Review, we describe the pathogenesis of this disease, with a focus on recent mechanistic insights into virulence factor function. We also discuss the changing epidemiology of pertussis and the challenges of vaccine development. Despite decades of research, many aspects of B. pertussis physiology and pathogenesis remain poorly understood. We highlight knowledge gaps that must be addressed to develop improved vaccines and therapeutic strategies

Angiographic progression of coronary artery disease and the development of myocardial infarction

AbstractThere are few data on angiographic coronary artery anatomy in patients whose coronary artery disease progresses to myocardial infarction. In this retrospective analysis, progression of coronary artery disease between two cardiac catheterization procedures is described in 38 patients: 23 patients (Group I) who had a myocardial infarction between the two studies and 15 patients (Group II) who presented with one or more new total occlusions at the second study without sustaining an intervening infarction.In Group I the median percent stenosis on the initial angiogram of the artery related to the infarct at restudy was significantly less than the median percent stenosis of lesions that subsequently were the site of a new total occlusion in Group II (48 versus 73.5%, p < 0.05). In the infarctrelated artery in Group I, only 5 (22%) of 23 lesions were initially >70%, whereas in Group II, 11 (61%) of 18 lesions that progressed to total occlusion were initially >70% (p < 0.01). In Group I, patients who developed a Q wave infarction had less severe narrowing at initial angiography in the subsequent infarct-related artery (34%) than did patients who developed a non-Q wave infarction (80%) (p < 0.05). Univariate and multivariate analysis of angiographic and clinical characteristics present at initial angiography in Group I revealed proximal lesion location as the only significant predictor of evolution of lesions ≥ 50% to infarction.This irrespective study suggests that myocardial infarction frequently develops from previously nonsevere lesions. In addition, it is often difficult to predict the location of a subsequent infarct from analysis of the first coronary angiogram. Non-Q wave infarction is usually preceded by a more severe pre-existing stenosis than is a Q wave infarction, perhaps indicating some degree of prior myocardial protection. A prospective evaluation will be necessary to confirm these findings

The Prodomain of the Bordetella Two-Partner Secretion Pathway Protein FhaB Remains Intracellular yet Affects the Conformation of the Mature C-terminal Domain

Two-Partner Secretion (TPS) systems use β-barrel proteins of the Omp85-TpsB superfamily to transport large exoproteins across the outer membranes of Gram-negative bacteria. The Bordetella FHA/FhaC proteins are prototypical of TPS systems in which the exoprotein contains a large C-terminal prodomain that is removed during translocation. Although it is known that the FhaB prodomain is required for FHA function in vivo, its role in FHA maturation has remained mysterious. We show here that the FhaB prodomain is required for the extracellularly-located mature C-terminal domain (MCD) of FHA to achieve its proper conformation. We show that the C-terminus of the prodomain is retained intracellularly and that sequences within the N-terminus of the prodomain are required for this intracellular localization. We also identify sequences at the C-terminus of the MCD that are required for release of mature FHA from the cell surface. Our data support a model in which the intracellularly-located prodomain affects the final conformation of the extracellularly-located MCD, which, we hypothesize, triggers cleavage and degradation of the prodomain

Randomized trial of conventional transseptal needle versus radiofrequency energy needle puncture for left atrial access (the TRAVERSE-LA study).

BackgroundTransseptal puncture is a critical step in achieving left atrial (LA) access for a variety of cardiac procedures. Although the mechanical Brockenbrough needle has historically been used for this procedure, a needle employing radiofrequency (RF) energy has more recently been approved for clinical use. We sought to investigate the comparative effectiveness of an RF versus conventional needle for transseptal LA access.Methods and resultsIn this prospective, single-blinded, controlled trial, 72 patients were randomized in a 1:1 fashion to an RF versus conventional (BRK-1) transseptal needle. In an intention-to-treat analysis, the primary outcome was time required for transseptal LA access. Secondary outcomes included failure of the assigned needle, visible plastic dilator shavings from needle introduction, and any procedural complication. The median transseptal puncture time was 68% shorter using the RF needle compared with the conventional needle (2.3 minutes [interquartile range {IQR}, 1.7 to 3.8 minutes] versus 7.3 minutes [IQR, 2.7 to 14.1 minutes], P = 0.005). Failure to achieve transseptal LA access with the assigned needle was less common using the RF versus conventional needle (0/36 [0%] versus 10/36 [27.8%], P &lt; 0.001). Plastic shavings were grossly visible after needle advancement through the dilator and sheath in 0 (0%) RF needle cases and 12 (33.3%) conventional needle cases (P &lt; 0.001). There were no differences in procedural complications (1/36 [2.8%] versus 1/36 [2.8%]).ConclusionsUse of an RF needle resulted in shorter time to transseptal LA access, less failure in achieving transseptal LA access, and fewer visible plastic shavings

Biodiversity and Ecosystem Function in the Gulf of Maine: Pattern and Role of Zooplankton and Pelagic Nekton

This paper forms part of a broader overview of biodiversity of marine life in the Gulf of Maine area (GoMA), facilitated by the GoMA Census of Marine Life program. It synthesizes current data on species diversity of zooplankton and pelagic nekton, including compilation of observed species and descriptions of seasonal, regional and cross-shelf diversity patterns. Zooplankton diversity in the GoMA is characterized by spatial differences in community composition among the neritic environment, the coastal shelf, and deep offshore waters. Copepod diversity increased with depth on the Scotian Shelf. On the coastal shelf of the western Gulf of Maine, the number of higher-level taxonomic groups declined with distance from shore, reflecting more nearshore meroplankton. Copepod diversity increased in late summer, and interdecadal diversity shifts were observed, including a period of higher diversity in the 1990s. Changes in species diversity were greatest on interannual scales, intermediate on seasonal scales, and smallest across regions, in contrast to abundance patterns, suggesting that zooplankton diversity may be a more sensitive indicator of ecosystem response to interannual climate variation than zooplankton abundance. Local factors such as bathymetry, proximity of the coast, and advection probably drive zooplankton and pelagic nekton diversity patterns in the GoMA, while ocean-basin-scale diversity patterns probably contribute to the increase in diversity at the Scotian Shelf break, a zone of mixing between the cold-temperate community of the shelf and the warm-water community offshore. Pressing research needs include establishment of a comprehensive system for observing change in zooplankton and pelagic nekton diversity, enhanced observations of underknown\u27\u27 but important functional components of the ecosystem, population and metapopulation studies, and development of analytical modeling tools to enhance understanding of diversity patterns and drivers. Ultimately, sustained observations and modeling analysis of biodiversity must be effectively communicated to managers and incorporated into ecosystem approaches for management of GoMA living marine resources

D₂ Dopamine Receptors Colocalize Regulator of G-Protein Signaling 9-2 (RGS9-2) via the RGS9 DEP Domain, and RGS9 Knock-Out Mice Develop Dyskinesias Associated with Dopamine Pathways

Regulator of G-protein signaling 9-2 (RGS9-2), a member of the RGS family of Gα GTPase accelerating proteins, is expressed specifically in the striatum, which participates in antipsychotic-induced tardive dyskinesia and in levodopa-induced dyskinesia. We report that RGS9 knock-out mice develop abnormal involuntary movements when inhibition of dopaminergic transmission is followed by activation of D₂-like dopamine receptors (DRs). These abnormal movements resemble drug-induced dyskinesia more closely than other rodent models. Recordings from striatal neurons of these mice establish that activation of D₂-like DRs abnormally inhibits glutamate-elicited currents. We show that RGS9-2, via its DEP domain (for Disheveled, EGL-10, Pleckstrin homology), colocalizes with D₂DRs when coexpressed in mammalian cells. Recordings from oocytes coexpressing D₂DR or the m2 muscarinic receptor and G-protein-gated inward rectifier potassium channels show that RGS9-2, via its DEP domain, preferentially accelerates the termination of D₂DR signals. Thus, alterations in RGS9-2 may be a key factor in the pathway leading from D₂DRs to the side effects associated with the treatment both of psychoses and Parkinson's disease