The epidermal growth factor (EGF) receptor is activated by both EGF and transforming growth factor-alpha (TGF-a). Using immunohistochemical and immunoblotting techniques we now report that the EGF receptor, EGF, and TGF-a are found in both pancreatic acini and ducts in the normal human pancreas, and that all three proteins are expressed at higher levels in human pancreatic cancer tissues. Using in situ hybridization techniques, we also report that the mRNA encoding the EGF receptor, EGF, and TGF-a colocalize with their respective proteins. Northern blot analysis of total RNA indicates that, by comparison with the normal pancreas, the pancreatic tumors exhibit a 3-, 15-, and 10-fold increase in the mRNA levels encoding the EGF receptor, EGF, and TGF-a, respectively. Furthermore, by in situ hybridization, there is a marked increase in these mRNA moieties within the tumor mass. These findings suggest that EGF and TGF-a may participate in the regulation of normal pancreatic exocrine function, and that overexpression of the EGF receptor and its two principal ligands may contribute to the pathophysiological processes that occur in human pancreatic cancer. (J. Clin. Invest. 1992Invest. . 90:1352Invest. -1360

Active human visceral leishmaniasis (VL) is characterized by a progressive increase in visceral parasite burden, cachexia, massive splenomegaly, and hypergammaglobulinemia. In contrast, mice infected with Leishmania donovani, the most commonly studied model of VL, do not develop overt, progressive disease. Furthermore, mice control Leishmania infection through the generation of NO, an effector mechanism that does not have a clear role in human macrophage antimicrobial function. Remarkably, infection of the Syrian hamster (Mesocricetus auratus) with L. donovani reproduced the clinicopathological features of human VL, and investigation into the mechanisms of disease in the hamster revealed striking differences from the murine model. Uncontrolled parasite replication in the hamster liver, spleen, and bone marrow occurred despite a strong Th1-like cytokine (IL-2, IFN-γ, and TNF/lymphotoxin) response in these organs, suggesting impairment of macrophage effector function. Indeed, throughout the course of infection, inducible NO synthase (iNOS, NOS2) mRNA or enzyme activity in liver or spleen tissue was not detected. In contrast, NOS2 mRNA and enzyme activity was readily detected in the spleens of infected mice. The impaired hamster NOS2 expression could not be explained by an absence of the NOS2 gene, overproduction of IL-4, defective TNF/lymphotoxin production (a potent second signal for NOS2 induction), or early dominant production of the deactivating cytokines IL-10 and TGF-β. Thus, although a Th1-like cytokine response was prominent, the major antileishmanial effector mechanism that is responsible for control of infection in mice was absent throughout the course of progressive VL in the hamster.

The ability of 20-50 nm nanoparticles to target and modulate the biology of specific types of cells will enable major advancements in cellular imaging and therapy in cancer and atherosclerosis. A key challenge is to load an extremely high degree of targeting, imaging, and therapeutic functionality into small, yet stable particles. Herein we report ~30 nm stable uniformly sized near-infrared (NIR) active, superparamagnetic nanoclusters formed by kinetically controlled self-assembly of goldcoated iron oxide nanoparticles. The controlled assembly of nanocomposite particles into clusters with small primary particle spacings produces collective responses of the electrons that shift the absorbance into the NIR region. The nanoclusters of ~70 iron oxide primary particles with thin gold coatings display intense NIR (700-850 nm) absorbance with a cross section of ~10 −14 m 2 . Because of the thin gold shells with an average thickness of only 2 nm, the r 2 spin-spin magnetic relaxivity is 219 mM −1 s −1 , an order of magnitude larger than observed for typical iron oxide particles with thicker gold shells. Despite only 12% by weight polymeric stabilizer, the particle size and NIR absorbance change very little in deionized water over 8 months. High uptake of the nanoclusters by macrophages is facilitated by the dextran coating, producing intense NIR contrast in dark field and hyperspectral microscopy, both in cell culture and an in vivo rabbit model of atherosclerosis. Small nanoclusters with optical, magnetic, and therapeutic functionality, designed by assembly of *Address correspondence to: kpj@che.utexas.edu, FELDMANM@uthscsa.edu. Supporting Information Available: Reproducibility in nanorose size distribution; porosity of dextran in the shells about the iron oxide particle; estimation of number of particles per nanocluster; average optical density spectra in macrophages labeled with nanorose by hyperspectral microscopy; and laser vaporization of macrophages in vitro. This material is available free of charge via the Internet at http://pubs.acs.org. NIH Public AccessAuthor Manuscript ACS Nano. Author manuscript; available in PMC 2010 September 22. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author Manuscript nanoparticle building blocks, offer broad opportunities for targeted cellular imaging, therapy, and combined imaging and therapy. Keywordsgold; iron oxide; nanocluster; near-infrared; macrophage targeted imaging; MRI; atherosclerosis; cancer Clinical imaging and/or therapy with multifunctional nanoparticles that target specific types of cells has the potential to transform health care in cancer, atherosclerosis, and other diseases. When the nanoparticle diameters are reduced to 20-50 nm, the biological pathways in targeted cells can undergo profound changes. [1][2][3][4][5] Small nanoparticles, the size of small viruses, permeate barriers more rapidly including cell membranes and leaky vasculature in cancers. The efficacy of vaccines may be enhanced with ultrasmall 20 nm nanoparticles that can dif...

Atherosclerosis is considered to be a chronic inflammatory disease characterized by enhanced expression of proinflammatory cytokines, chemokines, and adhesion molecules (1-3). The cross-talk between cytokines, chemokines, and infiltrating immune cells amplifies the inflammatory cascade in the vessel wall, resulting in atherogenesis (1-3).Interleukin-18 (IL-18) 3 is a proinflammatory and proatherogenic cytokine that induces the expression of other proinflammatory cytokines and adhesion molecules (4). IL-18 has been localized to human atherosclerotic lesions (5, 6), and circulating IL-18, which is increased in acute coronary syndromes (7), has been shown to predict future cardiovascular events (7). A positive correlation between serum IL-18 levels and carotid intima-media thickness has been demonstrated (8). Administration of IL-18 aggravates atherosclerosis in mice (9). Moreover, atherogenesis is reduced in IL-18-deficient apoE knock-out mice (10), suggesting a causal role for IL-18 in the development and progression of atherosclerosis.Recently, we demonstrated that IL-18 induces human aortic smooth muscle cell (SMC) proliferation (11). However, it is not known whether IL-18 induces SMC migration. Both migration and proliferation play a role in normal and diseased vessels (1-3). SMC migration contributes to normal angiogenesis. However, SMC migration also plays a causal role in pathological remodeling of the vessel walls during atherosclerosis, arteriosclerosis, and restenosis following angioplasty (1-3).Vessel wall remodeling is characterized by a disruption in the delicate balance between extracellular matrix (ECM) deposition and degradation, with matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of matrix metalloproteinases (TIMPs)) playing a prominent role. MMPs are zinc-dependent proteases and are classified as collagenases, stromelysins, elastases, and gelatinases based on substrate specificity. Their expression is regulated at both the transcriptional and post-transcriptional levels. They are synthesized as proenzymes and are activated following proteolytic cleavage. SMCs express MMP2 (gelatinase A) and MMP9 (gelatinase B), the two gelatinases described so far (12). Excess activation of MMP2 and MMP9, without alteration of TIMP expression and activation, results in destruction of the ECM and can lead to pathological remodeling and vascular restenosis (12-15). Because increased matrix degradation promotes SMC migration (15), we hypothesized that IL-18 induces SMC migration via induction of MMP9. Our novel findings demonstrate that IL-18 promotes SMC