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ABSTRACT: The objective of this work is to compare the characteristics of various techniques for functional renal imaging, with a focus on nuclear medicine and magnetic resonance imaging. Even with low spatial resolution and rather poor signal-to-noise ratio, classical nuclear medicine has the advantage of linearity and good sensitivity. It remains the gold standard technique for renal relative functional assessment. Technetium-99m ((99m)Tc)-labeled diethylenetriamine penta-acetate remains the reference glomerular tracer. Tubular tracers have been improved: (123)I- or (131)I-hippuran, (99m)Tc-MAG3 and, recently, (99m)Tc-nitrilotriacetic acid. However, advancement in molecular imaging has not produced a groundbreaking tracer. Renal magnetic resonance imaging with classical gadolinated tracers probably has potential in this domain but has a lack of linearity and, therefore, its value still needs evaluation. Moreover, the advent of nephrogenic systemic fibrosis has delayed its expansion. Other developments, such as diffusion or blood oxygen level-dependent imaging, may have a role in the future. The other modalities have a limited role in clinical practice for functional renal imaging.
Seminars in nuclear medicine 01/2011; 41(1):61-72. · 3.96 Impact Factor
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ABSTRACT: Tobacco smoking is responsible for a vast array of diseases, particularly chronic bronchitis and lung cancer. It is still unclear which constituent(s) of the smoke is responsible for its toxicity. The authors decided to focus on carbon dioxide, since its level of concentration in mainstream cigarette smoke is about 200 times higher than in the atmosphere. The authors previously demonstrated that inhalation of carbon dioxide concentrations above 5% has a deleterious effect on lungs. In this study, the authors assessed the inflammatory potential of carbon dioxide contained in cigarette smoke. Mice were exposed to cigarette smoke containing a high or reduced CO(2) level by filtration through a potassium hydroxyde solution. The inflammatory response was evaluated by histological analysis, protein phosphatase 2 A (PP2A) and nuclear factor (NF)-kappaB activation, and proinflammatory cytokine secretion measurements. The data show that the toxicity of cigarette smoke may be largely due to its high level of CO(2). Pulmonary injuries consequent to tobacco smoke inhalation observed by histology were greatly diminished when CO(2) was removed. Cigarette smoke exposure causes an inflammatory response characterized by PP2A and NF-kappaB activation followed by proinflammatory cytokine secretion. This inflammatory response was reduced when the cigarette smoke was filtered through a potassium hydroxide column, and reestablished when CO(2) was injected downstream from the filtration column.Given that there is an extensive literature linking a chronic inflammatory response to the major smoking-related diseases, these data suggest that carbon dioxide may play a key role in the causation of these diseases by tobacco smoking.
Inhalation Toxicology 04/2010; 22(7):543-51. · 1.92 Impact Factor
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ABSTRACT: Neogalactosylated and neolactosylated albumins are currently used as radiopharmaceutical agents for imaging the liver asialoglycoprotein receptors, which allows the quantification of hepatic liver function in various diseases and also in healthy liver transplant donors. We developed an original process for synthesizing a chelating neolactosylated human albumin using maleimidopropyl-lactose and maleimidopropyl-diethylene triamine pentaacetic acid (DTPA) derivatives. The lactosylated protein (LACTAL) conjugate showed excellent liver uptake compared to nonlactosylated protein and a very high signal-to-noise ratio, based on functional assessment of biodistribution in mice using (99m)Tc-scintigraphy.
Bioconjugate Chemistry 03/2010; 21(4):589-96. · 4.93 Impact Factor
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ABSTRACT: Intrapancreatic accessory spleen (IPAS) is ectopic splenic tissue distinct from the main spleen. A 46-year-old man with chronic hepatitis C, presented in 2006 with low right chest pain which led to a diagnosis of tuberculosis pleurisy. CT scan and MRI showed a round, homogenous, well limited mass of 3cm in the pancreas tail. Tc-99m heat-damaged red blood cell scintigraphy with SPECT-CT was performed to confirm the diagnosis of IPAS. Most cases of IPAS described in the literature were diagnosed by pathologists after distal pancreatectomy and splenectomy performed for a suspicion of pancreatic tumor. However, heat-damaged red blood cell scintigraphy remains the most commonly used diagnostic procedure for IPAS, even if superparamagnetic iron oxide MRI contrast agent may be used in the future.
Clinical nuclear medicine 10/2009; 34(9):642-4. · 3.92 Impact Factor
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ABSTRACT: The aim of this study was to assess whether one of the most common poisons of cellular respiration, i.e., carbon dioxide, is proinflammatory. CO(2) is naturally present in the atmosphere at the level of 0.038% and involved in numerous cellular biochemical reactions. We analyzed in vitro the inflammation response induced by exposure to CO(2) for 48 h (0-20% with a constant O(2) concentration of 21%). In vivo mice were submitted to increasing concentrations of CO(2) (0, 5, 10, and 15% with a constant O(2) concentration of 21%) for 1 h. The exposure to concentrations above 5% of CO(2) resulted in the increased transcription (RNase protection assay) and secretion (ELISA) of proinflammatory cytokines [macrophage inflammatory protein-1alpha (MIP-1alpha), MIP-1beta, MIP-2, IL-8, IL-6, monocyte chemoattractant protein-1, and regulated upon activation, normal T cell expressed, and, presumably, secreted (RANTES)] by epithelial cell lines HT-29 or A549 and primary pulmonary cells retrieved from the exposed mice. Lung inflammation was also demonstrated in vivo by mucin 5AC-enhanced production and airway hyperreactivity induction. This response was mostly mediated by the nuclear translocation of p65 NF-kappaB, itself a consequence of protein phosphatase 2A (PP2A) activation. Short inhibiting RNAs (siRNAs) targeted toward PP2Ac reversed the effect of carbon dioxide, i.e., disrupted the NF-kappaB activation and the proinflammatory cytokine secretion. In conclusion, this study strongly suggests that exposure to carbon dioxide may be more toxic than previously thought. This may be relevant for carcinogenic effects of combustion products.
AJP Lung Cellular and Molecular Physiology 02/2009; 296(4):L657-65. · 3.66 Impact Factor
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ABSTRACT: There are several reports suggesting hyperosmotic contents in the feces of patients suffering from inflammatory bowel disease (IBD). Previous works have documented that hyperosmolarity can cause inflammation attributable to methylation of the catalytic subunit of protein phosphatase 2A (PP2A) and subsequent NF-kappaB activation resulting in cytokine secretion. In this study, we demonstrate that dextran sulfate sodium (DSS) induces colitis due to hyperosmolarity and subsequent PP2A activation. Mice were randomized and fed with increased concentrations of DSS (0 mOsm, 175 mOsm, 300 mOsm, and 627 mOsm) for a duration of 3 wk or with hyperosmotic concentrations of DSS (627 mOsm) or mannitol (450 mOsm) for a duration of 12 wk. Long-term oral administration of hyposmotic DSS or mannitol had no demonstrable effect. Hyperosmotic DSS or mannitol produced a significant increase in colonic inflammation, as well as an increase in the weight of sacral lymph nodes and in serum amyloid A protein levels. Similar results were obtained through the ingestion of comparable osmolarities of mannitol. Hyperosmolarity induces the methylation of PP2A, nuclear p65 NF-kappaB activation. and cytokine secretion. The rectal instillation of okadaic acid, a well-known PP2A inhibitor, reverses the IBD. Short inhibiting RNAs (siRNAs) targeted toward PP2Ac reverse the effect of hyperosmotic DSS. The present study strongly suggests that DSS-induced chronic colitis is a consequence of the methylation of PP2Ac induced by hyperosmolarity.
AJP Gastrointestinal and Liver Physiology 09/2008; 295(5):G934-41. · 3.43 Impact Factor
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ABSTRACT: A 2-year-old child underwent liver transplant and was referred for postsurgical abdominal pain. Hepatobiliary scintigraphy with Tc-99m iminodiacetic acid (IDA) was performed and with the help of 24-hour delayed images, the diagnosis of biliary leak at the site of anastomosis was made possible. This case report confirms the value of delayed images to facilitate the diagnosis in unequivocal situations and reminds us of the usefulness of this noninvasive method, especially in pediatrics.
Clinical Nuclear Medicine 02/2008; 33(1):44-5. · 3.67 Impact Factor
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European journal of nuclear medicine and molecular imaging 05/2007; 34(4):606. · 4.99 Impact Factor
