Molecular Imaging of Experimental Abdominal Aortic Aneurysms

Current laboratory research in the field of abdominal aortic aneurysm (AAA) disease often utilizes small animal experimental models induced by genetic manipulation or chemical application. This has led to the use and development of multiple high-resolution molecular imaging modalities capable of tracking disease progression, quantifying the role of inflammation, and evaluating the effects of potential therapeutics. In vivo imaging reduces the number of research animals used, provides molecular and cellular information, and allows for longitudinal studies, a necessity when tracking vessel expansion in a single animal. This review outlines developments of both established and emerging molecular imaging techniques used to study AAA disease. Beyond the typical modalities used for anatomical imaging, which include ultrasound (US) and computed tomography (CT), previous molecular imaging efforts have used magnetic resonance (MR), near-infrared fluorescence (NIRF), bioluminescence, single-photon emission computed tomography (SPECT), and positron emission tomography (PET). Mouse and rat AAA models will hopefully provide insight into potential disease mechanisms, and the development of advanced molecular imaging techniques, if clinically useful, may have translational potential. These efforts could help improve the management of aneurysms and better evaluate the therapeutic potential of new treatments for human AAA disease

A 150-kDa molecule of macrophage membrane stimulates interleukin-2 and interferon-γ production and proliferation of ovalbumin-specific CD4<SUP>+</SUP> T cells

In the present study, we describe the potential co-stimulatory role of a macrophage membrane-associated protein of 150 kDa (M150). The protein was isolated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and was found to be a single molecule on two-dimensional gel electrophoresis. The molecule was re-constituted in phosphatidyl choline vesicles and tested for its ability to promote the proliferation and the secretion of lymphokines from T helper (Th) cells. The reconstituted M150 induced a significant proliferation of anti-CD3 monoclonal antibody (mAb)-stimulated ovalbumin-specific CD4<SUP>+</SUP> T cells. Further, Th cells activated with this molecule in the presence of anti-CD3 mAb mainly secreted interleukin (IL)-2 and interferon- but not IL-4. M150 could not promote the proliferation of Th cells, or lymphokine secretion in the absence of anti-CD3 mAb. These observations suggest that M150 acts by selectively activating a Th1-like immune response

Intravenous urography supplemented with computerised tomography urogram: A pragmatic hybrid imaging approach to hydronephrosis

Background: Image quality in an Intravenous Urogram (IVU) can occasionally be compromised by variables like bowel preparation, renal function and radiographic factors, posing a challenge to all Uroradiologists. The Computerised Tomography Urogram (CTU) yields better diagnostic information than an IVU, due to its inherent superior anatomic delineation and contrast sensitivity, against a trade-off involving radiation dose and cost. Our study was conducted to assess the utility and timing of performing a single-phase CTU, as a problem-solving tool, to clear the diagnostic dilemma in a selected subset of patients, in whom an ongoing IVU could potentially be inconclusive. Material and Methods: Five hundred and twelve patients who underwent IVU studies for urologic referrals at a tertiary care hospital, during the period of January to December 2009, formed the subject of the study, of whom 33 patients with inconclusive IVU findings after the first three radiographs underwent a single-phase CTU, to reach definitive imaging diagnoses. Results: The percentage of inconclusive IVU studies amounted to only 33 / 512 (6.4%), in whom a CTU study revealed definitive diagnoses in 30 patients and no abnormality in three patients, thus conclusively clearing the ambiguities raised on the IVU in all the selected patients. Conclusions: The concept of a CTU limited to a single-phase study to supplement an inconclusive IVU optimizes the contrast and radiation dose to the affected patients. It is a cost-effective, timely, and definitive ′imaging intervention′ and should be considered a viable hybrid technique to be utilized selectively and judiciously

M150 modulates the costimulatory signals delivered by B cells to T cells and enhances their ability to help B cells

There is a prerequirement of at least two sets of signals delivered by the antigen-presenting cell (APC) for the optimal activation of T helper (Th) cells. The First signal is provided by the engagement of T cell receptor with the antigen-MHC class II complex, followed by a second stimulus in the form of costimulatory signals. In the present study, we provide evidence that in a T-dependent antigen-driven system, the signals generated by hapten-specific B cells to stimulate Th cells for the secretion of interleukin-2 (IL-2), interferon-γ (IFN-γ ), and IL-4 were differentially modified by M150, a 150-kDa molecule expressed on the surface of macrophages. When ovalbumin-specific Th cells were cultured in the presence of 2,4,6 trinitrophenol (TNP)-specific B cells, M150 significantly increased the proliferation of Th cells and the secretion of IL-2 and IFN- γ and decreased the production of IL-4. Further, Th cells stimulated with M150 acquired improved ability to help B cells, resulting in an increase in the number of antibody-secreting cells and in the production of TNP-specific IgG2a antibodies. M150 possibly promotes Th1-like cell activity, as evidenced by predominant secretion of IL-2, IFN-γ , and IgG2a but not IL-4 and IgG1