Citations

In the wake of the September 11, 2001, attacks and the subsequent anthrax scare, there is growing concern about the United States' vulnerability to terrorist use of Weapons of Mass Destruction (WMD). As part of ongoing preparation for this terrible reality, many jurisdictions have been conducting simulated terrorist incidents to provide training for the public safety community, hospitals, and public health departments. As an example of this national effort to improve domestic preparedness for such events, a large scale, multi-jurisdictional chemical weapons drill was conducted in Cincinnati, Ohio, on May 20, 2000. This drill depicted the components of the early warning system for hospitals and public health departments, the prehospital medical response to terrorism. Over the course of the exercise, emergency medical services personnel decontaminated, triaged, treated, and transported eighty-five patients. Several important lessons were learned that day that have widespread applicability to health care delivery systems nationwide, especially in the areas of decontamination, triage, on-scene medical care, and victim transportation. As this training exercise helped Cincinnati to prepare for dealing with future large scale WMD incidents, such drills are invaluable preparation for all communities in a world increasingly at risk from terrorist attacks.

We studied the endocytosis of fluorescent glycosphingolipid (GSL) analogs in various cell types using pathway-specific inhibitors and colocalization studies with endocytic markers and DsRed caveolin-1 (cav-1). Based on inhibitor studies, all GSLs tested were internalized predominantly (>80%) by a clathrin-independent, caveolar-related mechanism, regardless of cell type. In addition, fluorescent lactosylceramide (LacCer) colocalized with DsRed-cav-1 in vesicular structures upon endocytosis in rat fibroblasts. The internalization mechanism for GSLs was unaffected by varying the carbohydrate headgroup or sphingosine backbone chain length; however, a fluorescent phosphatidylcholine analog was not internalized via caveolae, suggesting that the GSL ceramide core may be important for caveolar uptake. Internalization of fluorescent LacCer was reduced 80–90% in cell types with low cav-1, but was dramatically stimulated by cav-1 overexpression. However, even in cells with low levels of cav-1, residual LacCer internalization was clathrin independent. In contrast, cholera toxin B subunit (CtxB), which binds endogenous GM1, was internalized via clathrin-independent endocytosis in cells with high cav-1 expression, whereas significant clathrin-dependent uptake occurred in cells with low cav-1. Fluorescent GM1, normally internalized by clathrin-independent endocytosis in HeLa cells with low cav-1, was induced to partially internalize via the clathrin pathway in the presence of CtxB. These results suggest that GSL analogs are selectively internalized via a caveolar-related mechanism in most cell types, whereas CtxB may undergo “pathway switching” when cav-1 levels are low.

Objective— Atherosclerotic renovascular disease (ARVD) aggravates renal scarring more than other causes of renal artery stenosis (RAS), but the underlying pathogenic mechanisms of this potential profibrotic effect remain unclear. We tested the hypothesis that coexistence of atherosclerosis and RAS interferes with renal tissue remodeling. Methods and Results— Single-kidney hemodynamics and function were quantified in vivo with electron-beam computed tomography in 3 groups of pigs (n=7 each): normal pigs, pigs 12 weeks after induction of unilateral RAS (RAS group), and pigs with similar-degree RAS fed a 12-week 2% hypercholesterolemic diet (HC+RAS, simulating early ARVD). Kidneys were studied ex vivo by Western blotting and immunohistochemistry. Renal volume, renal blood flow, and glomerular filtration rate were similarly decreased in RAS and HC+RAS ischemic kidneys, accompanied by similar increased expression of profibrotic factors like transforming growth factor-β, tissue inhibitor of metalloproteinase-1, and plasminogen activator inhibitor-1. Nevertheless, HC+RAS kidneys showed increased intrarenal fibrosis compared with RAS-only kidneys. Furthermore, expression of nuclear factor-κB was increased, expression of extracellular (matrix metalloproteinase-2) and intracellular (ubiquitin) protein degradation systems was decreased, and apoptosis was blunted. Conclusions— Diet-induced HC superimposed on RAS accelerates the development of fibrosis in the stenotic kidney by amplifying profibrotic mechanisms and disrupting tissue remodeling. These alterations might contribute to renal disease progression in ARVD and might account for the increased propensity for end-stage renal disease.

AbstractMyosin modulates the fibrinolytic process as a cofactor of the tissue plasminogen activator and as a substrate of plasmin. We report now that myosin is present in arterial thrombi and it forms reversible noncovalent complexes with fibrinogen and fibrin with equilibrium dissociation constants in the micromolar range (1.70 and 0.94 μM, respectively). Competition studies using a peptide inhibitor of fibrin polymerization (glycl-prolyl-arginyl-proline [GPRP]) indicate that myosin interacts with domains common in fibrinogen and fibrin and this interaction is independent of the GPRP-binding polymerization site in the fibrinogen molecule. An association rate constant of 1.81 × 102 M–1 · s–1 and a dissociation rate constant of 3.07 × 10–4 s–1 are determined for the fibrinogen-myosin interaction. Surface plasmon resonance studies indicate that fibrin serves as a matrix core for myosin aggregation. The fibrin clots equilibrated with myosin are stabilized against dissolution initiated by plasminogen and tissue-type plasminogen activator (tPA) or urokinase (at fibrin monomer-myosin molar ratio as high as 30) and by plasmin under static and flow conditions (at fibrin monomer-myosin molar ratio lower than 15). Myosin exerts similar effects on the tPA-induced dissolution of blood plasma clots. Covalent modification involving factor XIIIa does not contribute to this stabilizing effect; myosin is not covalently attached to the clot by the time of complete cross-linking of fibrin. Thus, our in vitro data suggest that myosin detected in arterial thrombi binds to the polymerized fibrin, in the bound form its tPA-cofactor properties are masked, and the myosinfibrin clot is relatively resistant to plasmin.

Abstract Nonrandom recurrent chromosomal abnormalities are ubiquitous in multiple myeloma (MM) and include, among others, translocations of the immunoglobulin heavy chain locus (IgH). IgH translocations in MM result in the up-regulation of oncogenes, and include more commonly t(11;14)(q13;q32), t(4;14)(p16;q32), and t(14;16)(q32;q23). Based on the recurrent nature of these translocations and their finding since the early stages of the plasma cell (PC) disorders, we hypothesized that they would confer biologic and clinical variability. In addition, deletions of 13q14 and 17p13 have also been associated with a shortened survival. We used cytoplasmic Ig—enhanced interphase fluorescent in situ hybridization to detect deletions (13q14 and 17p13.1), and translocations involving IgH in 351 patients treated with conventional chemotherapy entered into the Eastern Cooperative Oncology Group clinical trial E9486/9487. Translocations were frequently unbalanced with loss of one of the derivative chromosomes. The presence of t(4; 14)(p16;q32) (n = 42; 26 vs 45 months, P < .001), t(14;16)(q32;q23) (n = 15; 16 vs 41 months, P = .003), – 17p13 (n = 37; 23 vs 44 months, P = .005), and – 13q14 (n = 176; 35 vs 51 months, P = .028) were associated with shorter survival. A stratification of patients into 3 distinct categories allowed for prognostication: poor prognosis group (t(4;14)(p16;q32), t(14; 16)(q32;q23), and – 17p13), intermediate prognosis (– 13q14), and good prognosis group (all others), with median survivals of 24.7, 42.3, and 50.5 months, respectively (P < .001). This molecular cytogenetic classification identifies patients into poor, intermediate, and good risk categories. More importantly it provides further compelling evidence that MM is composed of subgroups of patients categorized according to their underlying genomic aberrations.

SUMMARY Precise coupling of spatially separated intracellular ATP-producing and ATP-consuming processes is fundamental to the bioenergetics of living organisms, ensuring a fail-safe operation of the energetic system over a broad range of cellular functional activities. Here, we provide an overview of the role of spatially arranged enzymatic networks, catalyzed by creatine kinase,adenylate kinase, carbonic anhydrase and glycolytic enzymes, in efficient high-energy phosphoryl transfer and signal communication in the cell. Studies of transgenic creatine kinase and adenylate kinase deficient mice, along with pharmacological targeting of individual enzymes, have revealed the importance of near-equilibrium reactions in the dissipation of metabolite gradients and communication of energetic signals to distinct intracellular compartments,including the cell nucleus and membrane metabolic sensors. Enzymatic capacities, isoform distribution and the dynamics of net phosphoryl flux through the integrated phosphotransfer systems tightly correlate with cellular functions, indicating a critical role of such networks in efficient energy transfer and distribution, thereby securing the cellular economy and energetic homeostasis under stress.