Beta Imager

Selected Publications

Neurosciences

Le S, Finn JP, Larijani M, Marino MJ, Schaffhauser H: Detection of low level histamine H(3) receptor occupancy by autoradiography J Neurosci Methods September (2009)

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Le S, Finn JP, Larijani M, Marino MJ, Schaffhauser H: Detection of low level histamine H(3) receptor occupancy by autoradiography J Neurosci Methods September (2009)

Abstract
Histamine H(3) receptor antagonists have been proposed as a novel approach to the treatment of cognitive, attentional, and sleep disorders. It is apparent that H(3) receptor antagonists produce in vivo effects in preclinical animal models of central diseases across a wide dose range. In order to characterize the relationship between efficacy in the preclinical models and H(3) receptor occupancy, a brain slice receptor autoradiography method was used. Brain slice receptor autoradiography requires less in vitro tissue processing, preserves brain structure, and provides anatomical localization of compound in the brain. Consistent with H(3) receptor distribution, in vitro autoradiography experiments demonstrated specific binding of [(3)H]NAMH (N-alpha-methylhistamine) in rat cortex, and other brain regions, but not in cerebellum. Ex vivo H(3)R brain slice autoradiography was able to detect H(3) receptor occupancy by reference antagonists at doses lower than previously found using a homogenate assay format. The method is relatively quick with image acquisition on a beta-imager and is capable of detecting receptor occupancy in different brain regions simultaneously. Furthermore, the increased sensitivity should be useful in providing dosing guidelines for H(3) antagonists in both preclinical and clinical settings.

Kang K, Huang XF, Wang Q, Deng C: Decreased density of serotonin 2A receptors in the superior temporal gyrus in schizophrenia-a postmortem study Prog Neuropsychopharmacol Biol Psychiatry 33(5):867-71 August (2009)

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Abstract
The superior temporal gyrus (STG) is strongly implicated in the pathophysiology of schizophrenia, particularly with regards to auditory hallucinations. In this study, using in situ quantitative autoradiography in postmortem tissue, we investigated the binding of the [3H]ketanserin to 5-HT(2A) receptors and [3H]mesulergine to 5-HT(2C) receptors in the left STG of 8 male schizophrenic patients compared to 8 control subjects. A strong [3H]ketanserin binding was observed in the STG, however there was a very weak [3H]mesulergine binding in the STG. A significant decrease in binding of [(3)H]ketanserin was clearly observed in schizophrenia patients in comparison with control subjects. There were no significant correlations between 5-HT(2A) binding density and age, postmortem intervals, or brain pH. These results suggest that the alterations of the 5-HT(2A) receptors contribute to the pathophysiology of the STG in schizophrenia. Furthermore, there is a clear tendency for a positive correlation between 5-HT(2A) and muscarinic M1 receptor bindings, and for negative correlations between 5-HT(2A) and GABA(A) receptor bindings and between muscarinic M1 and GABA(A) receptor bindings. This provides a possible mechanism of auditory hallucinations through interactions between 5-HT(2A), acetylcholine muscarinic and GABA transmissions in the STG in schizophrenia.

Wang Q, Zengin A, Deng C, Li Y, Newell KA, Yang GY, Lu Y, Wilder-Smith EP, Zhao H, Huang XF: High dose of simvastatin induces hyperlocomotive and anxiolytic-like activities: The association with the up-regulation of NMDA receptor binding in the rat brain Exp Neurol 216(1):132-8 March (2009)

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Abstract
Statins are widely being used for the treatment of a variety of conditions beyond their original indication for lowering cholesterol. We have previously reported that simvastatin affected the dopaminergic system in the rat brain. This study aims to investigate locomotor and anxiety effects along with the regional changes of N-methyl-d-aspartate (NMDA) receptors in the rat brain after 4-week administration of simvastatin. Hyperlocomotive and anxiolytic-like activities in the rat were observed after chronic administration of high dose simvastatin (10 mg/kg/day). Distributions and alterations of NMDA receptors in the post-mortem rat brain were detected by [(3)H] MK-801 binding autoradiography. Simvastatin increased [(3)H] MK-801 binding, predominantly in the prefrontal cortex (20%, p=0.003), primary motor cortex (20%, p<0.001), cingulate cortex (28%, p<0.001), hippocampus (41%, p<0.001), caudate putamen (30%, p=0.029), nucleus accumbens (27%, p=0.035) and amygdala (45%, p<0.001) compared to controls. Significant positive correlations were identified between hyperlocomotive as well as anxiolytic-like activities and the upregulation of NMDA receptors in different brain regions. Our results also provide strong evidence that chronic high dose simvastatin administration is to exhibit NMDA antagonist-like effects, which would partially explain the anxiolytic and hyperlocomotor activities. These findings contribute to a better understanding of the critical roles of simvastatin in modulating psycho-neurodegenerative disorders, via NMDA receptors.

Southam E, Cilia J, Gartlon JE, Woolley ML, Lacroix LP, Jennings CA, Cluderay JE, Reavill C, Rourke C, Wilson DM, Dawson LA, Medhurst AD, Jones DN: Preclinical investigations into the antipsychotic potential of the novel histamine H3 receptor antagonist GSK207040 Psychopharmacology (Berl). 201(4):483-94 January (2009)

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Abstract
OBJECTIVES: To test the novel nonimidazole histamine H3 receptor antagonist 5-[(3-cyclobutyl-2,3,4,5-tetrahydro-1H-3-benzazapin-7-yl)oxy]-N-methyl-2-pyrazinecarboxamide (GSK207040) in a series of behavioral and neurochemical paradigms designed to evaluate its antipsychotic potential. MATERIALS AND METHODS: Acute orally administered GSK207040 was investigated for its capacity to reverse a 24-h-induced deficit in novel object recognition memory, deficits in prepulse inhibition (PPI) induced by isolation rearing, and hyperlocomotor activity induced by amphetamine. The acute neurochemical effects of GSK207040 were explored by analyzing rat anterior cingulate cortex microdialysates for levels of dopamine, noradrenaline, and acetylcholine and by c-fos immunohistochemistry. The potential for interaction with the antipsychotic dopamine D2 receptor antagonist haloperidol was explored behaviorally (spontaneous locomotor activity and catalepsy), biochemically (plasma prolactin), and via ex vivo receptor occupancy determinations. RESULTS: GSK207040 significantly enhanced object recognition memory (3 mg/kg) and attenuated isolation rearing-induced deficits in PPI (1.0 and 3.2 mg/kg) but did not reverse amphetamine-induced increases in locomotor activity. There was no evidence of an interaction of GSK207040 with haloperidol. GSK207040 (3.2 mg/kg) raised extracellular concentrations of dopamine, noradrenaline, and acetylcholine in the anterior cingulate cortex and c-fos expression in the core of the nucleus accumbens was increased at doses of 3.2 and 10.0 mg/kg. CONCLUSIONS: The behavioral and neurochemical profile of GSK207040 supports the potential of histamine H3 receptor antagonism to treat the cognitive and sensory gating deficits of schizophrenia. However, the failure of GSK207040 to reverse amphetamine-induced locomotor hyperactivity suggests that the therapeutic utility of histamine H(3) receptor antagonism versus positive symptoms is less likely, at least following acute administration.

Even N, Cardona A, Soudant M, Corringer PJ, Changeux JP, Cloëz-Tayarani I: Regional differential effects of chronic nicotine on brain alpha 4-containing and alpha 6-containing receptors Neuroreport. 19(15):1545-50 October (2008)

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Abstract
Chronic nicotine upregulates central nicotinic acetylcholine receptors (nAChRs), a plasticity process thought to contribute to its addictive properties. To analyze this process in vivo, we chronically exposed mice to nicotine using minipump delivering nicotine at concentrations close to those found in tobacco smokers. Binding studies show upregulation of high-affinity nAChRs after 21 days of treatment in cortical areas, caudate putamen, nucleus accumbens, hippocampus, ventral tegmental area, and superior colliculi. No upregulation was observed in thalamus and discrete cortical areas. Using wild type and alpha 6-/- mice, we observed a downregulation of alpha 6*-nAChRs in superior colliculi and no effects in other structures. The complex pattern of upregulation/downregulation observed in this study depends on both nAChR composition and regional distribution.

Weston-Green K, Huang XF, Han M, Deng C.: The effects of antipsychotics on the density of cannabinoid receptors in the dorsal vagal complex of rats: implications for olanzapine-induced weight gain Int J Neuropsychopharmacol. 11:827-835 September (2008)

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Abstract
Some atypical antipsychotics clinically used to treat schizophrenia induce weight gain by unknown mechanisms. The dorsal vagal complex (DVC) of the brainstem and the endogenous cannabinoid system are implicated in the regulation of appetite signalling and food intake. We investigated whether antipsychotic drugs alter cannabinoid receptor-binding density in the DVC. Female Spraguewk (short-term) or 120.83, p=0.01). In addition, only chronic olanzapine treatment increased food intake. These results show that olanzapine, an antipsychotic with a high risk of weight gain as a side-effect, significantly decreased cannabinoid receptor binding in the DVC, whilst aripiprazole and haloperidol, antipsychotics with a low risk of weight gain had little or no effect on binding. These results suggest that a mechanism for antipsychotic-induced weight gain may be through the modulation of cannabinoid receptors in the DVC.

Poisnel G, Quentin T, Barré L, Coquerel A, Debruyne D: ompetitive displacement binding assay on rat brain sections and using a beta-imager: application to mu-opioid ligands J Neurosci Methods. 154(1-2), 60-67 June (2006)

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Abstract
A new approach of competitive displacement binding assay using brain sections and a beta-imager is presented to estimate binding parameters such as affinity and selectivity of new compounds or to characterize receptor families or subtypes of receptors in small brain regions. This method includes a preliminary saturation assay intended to define the optimal concentration of displaceable radio-labeled ligand followed by the determination of displacement constants (IC(50) and K(i)) in cerebral regions rich in studied receptor. The technique application was demonstrated in seven rat brain structures, using displacement of the selective tritiated mu-opioid ligand [(3)H]-DAMGO by six opioid ligands: a specific agonist (DAMGO), less specific agonists (morphine, remifentanil), a non-specific antagonist with good affinity for mu receptors (naloxone) and ligands specific of other opioid subtypes (naltrindole, U50.488). Radioactivity counts were collected during 48 h. The assay-validation was performed by measuring intra- and inter-assay variation on determinations and by comparing presently obtained K(i) values with data from recognised methodologies. Both prove the accuracy of the proposed method.

Quentin T, Debruyne D, Lelong-Boulouard V, Poisnel G, Barre L, Coquerel A: Clorazepate affects cell surface regulation of delta and kappa opioid receptors, thereby altering buprenorphine-induced adaptation in the rat brain Brain Res. 1063(1), 84-95 November (2005)

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Abstract
Concomitant abuse of buprenorphine (BPN) and benzodiazepines (BZD) may relate to a pharmacodynamic interaction between the two. The objective of the present work was to investigate the acute and chronic effects of clorazepate (CRZ) alone or in combination with BPN on selective kappa opiate tritiated ligand [3H]-U69 593 and delta opiate radioligand [3H]-deltorphine II binding in the rat brain. Bmax (maximal receptor density) and Kd (the dissociation constant) were directly determined at different brain regions of interest (ROI) selected for high densities of kappa and/or delta receptors in rats treated with BPN and/or CRZ. The agents were administered either once or for 21 consecutive days. Differences in Bmax and Kd (for both specific ligands) were related to drug treatment and receptor location. Globally, single BPN administration induced no changes in kappa or delta opiate receptor binding, whereas repeated BPN administration up-regulated kappa receptor density and decreased delta affinity. At the kappa receptor level, repeated administration of CRZ acted only on Kd, whereas the delta receptor was up-regulated. Repeated addition of CRZ to BPN had no effect on kappa receptor Bmax versus chronic controls. By significantly decreasing Bmax, CRZ nullified the effect of chronic BPN on the kappa receptor. The modifications were strongest in the nucleus accumbens, where both types of receptor occur. Treatments had region-selective effects in some brain areas, such as the amygdala, periaqueductal gray matter, hypothalamus and caudate putamen. Increased mu and delta receptor densities would be expected to provide reinforcement by enhancing reward, and impairment of kappa receptor availability would be expected to decrease aversion. The effects described are likely to influence addictive behavior among people abusing BZD and BPN.

Debruyne D, Quentin T, Poisnel G, Lelong-Boulouard V, Barré L, Coquerel A: Acute and chronic administration of clorazepate modifies the cell surface regulation of mu opioid receptors induced by buprenorphine in specific regions of the rat brain Brain Res. 1052(2):222-31 August (2005)

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Abstract
The aim of the present study was to investigate the acute and chronic effects of clorazepate (CRZ) alone or in combination with buprenorphine (BPN) on binding of the selective mu opiate tritiated ligand [3H]-DAMGO in the rat brain. Using 0.1 to 5 nM [3H]-DAMGO concentrations and a beta-imager, Bmax (maximal receptor density) and K(D) (the dissociation constant) were directly determined at different regions of interest (ROI) in the brains of rats treated with BPN and/or CRZ administered either once or over 21 consecutive days. Differences in Bmax and K(D) were related to both treatment and location. Acute BPN induced a down-regulation (62% mean decrease in Bmax observed on the whole brain) of mu opiate receptors. CRZ induced a mean 39% decrease in Bmax associated with substantially decreased affinity, particularly after acute administration (136% mean K(D) increase). Addition of CRZ to BPN [mean Bmax decreases of 34% (acute) and 29% (chronic)] induced significantly less down-regulation than did BPN alone, while altering affinity. These changes were maximal in the amygdaloid nucleus. Significant and persistent decreases in Bmax and affinity were also detected in the hippocampus, hypothalamus and thalamus. In the thalamus, an opposite regulation of Bmax was observed that was maximal with the combination. As the regions where changes were greatest have been specifically implicated in memory and socio-emotional functions and/or vegetative and endocrine adaptations, there is reason to suspect that the addition of CRZ to BPN may have clinical consequences. On the one hand, it may have some impact on drug abuse and misuse behaviors towards treatments including heroin substitute and BZD, and on the other, amplify the BPN effect-particularly hedonic or toxic-mainly after sporadic BPN-BZD abuses. These pharmacodynamic findings may explain, at least in part, the well-established preference of patients for the BPN-benzodiazepine combination and the toxicity with which it is associated.

Ottico E, Prinetti A, Prioni S, Giannotta C, Basso L, Chigorno V, Sonnino S: Dynamics of membrane lipid domains in neuronal cells differentiated in culture J Lipid Res. 44(11), 2142-2151 August (2003)

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Abstract
Treatment with methyl-beta-cyclodextrin (MCD) induced a time- and dose-dependent efflux of cholesterol, sphingolipids, and phosphatidylcholine (PC) from cerebellar neurons differentiated in culture. With a 'mild' treatment, the loss of cell lipids induced a deep reorganization of the remaining membrane lipids. In fact, the amount of PC associated with a Triton X-100-insoluble membrane fraction (highly enriched in sphingolipids and cholesterol in nontreated cells) was lowered by the treatment. This suggested a reduction of the lipid domain area. However, the cholesterol and sphingolipid enrichment of this fraction remained substantially unchanged, suggesting the existence of dynamic processes aimed at preserving the segregation of cholesterol and sphingolipids in membrane domains. Under these conditions, the lipid membrane domains retained the ability to sort signaling proteins, such as Lyn and c-Src, but cells displayed deep alterations in their membrane permeability. However, normal membrane permeability was restored by loading cells with cholesterol. When MCD treatment was more stringent, a large loss of cell lipids occurred, and the lipid domains were much less enriched in cholesterol and lost the ability to sort specific proteins. The loss of the integrity and properties of lipid domains was accompanied by severe changes in the membrane permeability, distress, and eventually cell death.

Crumeyrolle-Arias M, Medvedev A, Cardona A, Barritault D, Glover V: In situ imaging of specific binding of [3H]isatin in rat brain J Neurochem. 84(3), 618-620 January (2003)

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Crumeyrolle-Arias M, Medvedev A, Cardona A, Barritault D, Glover V: In situ imaging of specific binding of [3H]isatin in rat brain J Neurochem. 84(3), 618-620 January (2003)

Abstract
Isatin is an endogenous indole that influences a range of processes both in vivo and in vitro. It has a distinct and discontinuous distribution in the brain, as well as in other mammalian tissues and body fluids. However, the distribution of isatin binding sites in the brain is not known. Using a real-time beta-imager we have investigated the distribution of [3H]isatin-specific binding in rat brain sections. The highest labeling was found in hypothalamic nuclei and in the cortex, hippocampus, and cerebellum. Administration of the mechanism based monoamine oxidase inhibitor, pargyline, reduced but did not abolish the specific binding of [3H]isatin in the rat brain. The distribution became cortex, cerebellum, hypothalamus > hippocampus > brain stem > thalamus approximately striatum.

Langlois X, te Riele P, Wintmolders C, Leysen JE, Jurzak M: Use of the beta-imager for rapid ex vivo autoradiography exemplified with central nervous system penetrating neurokinin 3 antagonists J Pharmacol Exp Ther. 299(2), 712-717 November (2001)

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Abstract
The neurokinin 3 (NK3) receptor antagonists represent a novel class of pharmacological agents, which are currently under evaluation for the treatment of psychiatric disorders. An efficient brain penetration is one of the main prerequisites to further evaluate compounds displaying high potency to bind the NK3 receptor. The present report describes a method for determining the in vivo occupancy of central NK3 receptors after peripheral administration of drugs. An ex vivo measurement of NK3 receptor occupancy by quantitative autoradiography employing [3H]senktide as the radioligand has been developed. The speed of the method, which is usually considered low due to the time dedicated to film exposure (from weeks to months), has been considerably increased by the use of the beta -imager. The high sensitivity of this new radioimager was used to visualize and quantitatively analyze the [3H]senktide binding sites in brain sections within hours. Using this method, we have demonstrated that the reference NK3 antagonist SR142801 dose dependently occupied the NK3 receptors in the gerbil brain after subcutaneous administration with an ED50 of 0.85 mg/kg. The less active enantiomer SR142806 occupied the NK3 receptors only by 25% at the highest used dose of 10 mg/kg. These values are in accordance with the reported behavioral effects of the compounds. Our results indicate that ex vivo receptor occupancy measurements can be dependently used to predict the central activity of NK3 antagonists. More generally, the combination of ex vivo receptor autoradiography with the beta -imager detection constitutes a new and fast method to evaluate the brain penetration of drug candidates.

Oncology

Destouches D, El Khoury D, Hamma-Kourbali Y, Krust B, Albanese P, Katsoris P, Guichard G, Briand JP, Courty J, Hovanessian A: Suppression of Tumor Growth and Angiogenesis by a Specific Antagonist of the Cell-Surface Expressed Nucleolin PLoS ONE 3(6): e2518 January (2008)

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Abstract
BACKGROUND: Emerging evidences suggest that nucleolin expressed on the cell surface is implicated in growth of tumor cells and angiogenesis. Nucleolin is one of the major proteins of the nucleolus, but it is also expressed on the cell surface where is serves as a binding protein for variety of ligands implicated in cell proliferation, differentiation, adhesion, mitogenesis and angiogenesis. METHODOLOGY/PRINCIPAL FINDINGS: By using a specific antagonist that binds the C-terminal tail of nucleolin, the HB-19 pseudopeptide, here we show that the growth of tumor cells and angiogenesis are suppressed in various in vitro and in vivo experimental models. HB-19 inhibited colony formation in soft agar of tumor cell lines, impaired migration of endothelial cells and formation of capillary-like structures in collagen gel, and reduced blood vessel branching in the chick embryo chorioallantoic membrane. In athymic nude mice, HB-19 treatment markedly suppressed the progression of established human breast tumor cell xenografts in nude mice, and in some cases eliminated measurable tumors while displaying no toxicity to normal tissue. This potent antitumoral effect is attributed to the direct inhibitory action of HB-19 on both tumor and endothelial cells by blocking and down regulating surface nucleolin, but without any apparent effect on nucleolar nucleolin. CONCLUSION/SIGNIFICANCE: Our results illustrate the dual inhibitory action of HB-19 on the tumor development and the neovascularization process, thus validating the cell-surface expressed nucleolin as a strategic target for an effective cancer drug. Consequently, the HB-19 pseudopeptide provides a unique candidate to consider for innovative cancer therapy.

Sancey L, Ardisson V, Riou LM, Ahmadi M, Marti-Batlle D, Boturyn D, Dumy P, Fagret D, Ghezzi C, Vuillez JP: In vivo imaging of tumour angiogenesis in mice with the alpha(v)beta (3) integrin-targeted tracer (99m)Tc-RAFT-RGD Eur J Nucl Med Mol Imaging. 34(12), 2037-2047 August (2007)

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Abstract
PURPOSE: The molecular imaging of tumour neoangiogenesis currently represents a major field of research for the diagnostic and treatment strategy of solid tumours. Endothelial cells from tumour neovessels overexpress the alpha(v)beta(3) integrin, which selectively binds to Arg-Gly-Asp (RGD)-containing peptides. We evaluated the potential of the novel radiotracer (99m)Tc-RAFT-RGD for the non-invasive molecular imaging of alpha(v)beta(3) integrin expression in mice models of tumour development. METHODS: (99m)Tc-RAFT-RGD, (99m)Tc-cRGD (specific control) and (99m)Tc-RAFT-RAD (non-specific control) were injected intravenously to mice bearing B16F0 or TS/A-pc tumours. In vivo whole-body tomographic imaging and post-mortem biodistribution studies were performed 60 min following tracer injection. Adjacent tumour slices were used to compare the localisation of neovessels from immunostaining and the pattern of (99m)Tc-RAFT-RGD uptake from autoradiographic ex vivo imaging. RESULTS: Biodistribution studies indicated that (99m)Tc-RAFT-RGD tumour uptake was significantly higher than that of (99m)Tc-RAFT-RAD in B16F0 (2.4+/-0.5 vs 1.0+/-0.1%ID/g, respectively) and in TS/A-pc tumours (2.7+/-0.8 vs 0.7+/-0.1%ID/g, respectively). Immunohistochemical and autoradiographic studies indicated that (99m)Tc-RAFT-RGD intratumoural uptake preferentially occurred in angiogenic areas. Tomographic imaging allowed tumour visualisation following injection of (99m)Tc-RAFT-RGD and (99m)Tc-cRGD with similar tumour-to-contralateral muscle (T/CM) ratios in B16F0 and in TS/A-pc tumours whereas (99m)Tc-RAFT-RAD T/CM ratios did not allow tumour imaging. In accordance with the higher level of alpha(v)beta(3) integrin expression on TS/A-pc tumours than on B16F0 tumours as determined from western blot and immunoprecipitation analyses, the (99m)Tc-RAFT-RGD T/CM ratio was significantly higher in TS/A-pc than in B16F0 tumours. CONCLUSION: (99m)Tc-RAFT-RGD allowed the in vivo imaging of alpha(v)beta(3) integrin tumour expression.

David A, Steer D, Bregant S, Devel L, Makaritis A, Beau F, Yiotakis A, Dive V: Cross-linking yield variation of a potent matrix metalloproteinase photoaffinity probe and consequences for functional proteomics Angew Chem Int Ed Engl. 46(18), 3275-3277 April (2007)

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Dive V, Andarawewa KL, Boulay A, Matziari M, Beau F, Guerin E, Rousseau B, Yiotakis A, Rio MC: Dosing and scheduling influence the antitumor efficacy of a phosphinic peptide inhibitor of matrix metalloproteinases Int J Cancer. 113(5), 775-781 January (2005)

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Abstract
The in vivo disposition and antitumor efficacy of a newly developed phosphinic matrix metalloproteinase inhibitor (RXP03) were examined. RXP03 potently inhibits MMP-11, MMP-8 and MMP-13, but not MMP-1 and MMP-7. Twenty-four hours after i.p. injection into mice, most of the RXP03 was recovered intact in plasma, feces (biliary excretion) and tumor tissue. Pharmacokinetic parameters indicated that, after an i.p. dose of 100 microg/day, the plasma concentration of RXP03 over 24 hr remained higher than the Ki values determined for MMP-11, MMP-8 and MMP-13. Efficacy of RXP03 on the growth of primary tumors induced by s.c. injection of C(26) colon carcinoma cells in mice was observed to depend both on RXP03 doses and treatment schedules. Tumor volumes in mice treated for 18 days with 50, 100 and 150 microg/day of RXP03 were decreased compared with control tumor volumes, 100 microg/day being the most effective dose. Treatment at higher dose (600 microg/day) did not significantly reduce the tumor size as compared to control. Short treatments with RXP03 100 microg/day, 3 to 7 days after C(26) inoculation, were more effective on tumor growth than continuous treatment over 18 days. Strikingly, RXP03 treatment started 6 days after the C(26) injection and continued until day 18 led to stimulation of tumor growth, as compared to control. These paradoxical effects, depending on the RXP03 treatment schedule, underline the need to define carefully the spatiotemporal function of each MMP at various stages of tumor growth to achieve optimal therapeutic effects by MMP inhibitor treatment.

Microbiology

Zucchi I, Prinetti A, Scotti M, Valsecchi V, Valaperta R, Mento E, Reinbold R, Vezzoni P, Sonnino S, Albertini A, Dulbecco R: Association of rat8 with Fyn protein kinase via lipid rafts is required for rat mammary cell differentiation in vitro Proc Natl Acad Sci USA. 101(7), 1880-1885 February (2004)

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Abstract
We previously identified rat8 in the pathway involved in epithelial cell differentiation that occurs in the rat mammary gland at pregnancy when tubules and alveoli are formed. rat8, which encodes an IFN-inducible membrane protein, is the rat homologue of the mouse gene fragilis. By differential detergent extraction and isopycnic sucrose density gradients, we show that rat8 protein is associated to lipid membrane domains together with Lyn and Fyn, members of the Src tyrosine kinase family. We also show that recruitment of rat8 to lipid membrane domains is a necessary step in mammary epithelial cell differentiation. Immunoprecipitation analysis, performed with an anti-Fyn protein antibody, shows that rat8 was present in the Fyn immunoprecipitate. Antisense oligonucleotides, used to inhibit Fyn protein expression, block mammary cell differentiation. Taken together, these results suggest that the functional interaction, via lipid membrane domains, of rat8 and Fyn proteins is required for mammary cell differentiation. Therefore, rat8, like fragilis, may be involved in developmental decisions and the demarcation of a subset of cells in the mammary gland that cause epithelial cells to develop into a network of tubuloalveolar structures involved in secretion.

Rigothier MC, Khun H, Tavares P, Cardona A, Huerre M, Guillén N: Fate of Entamoeba histolytica during establishment of amoebic liver abscess analyzed by quantitative radioimaging and histology Infect Immun. 70(6), 3208-3215 January (2002)

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Abstract
The protozoan parasite Entamoeba histolytica is the causative agent of amoebiasis, a human disease characterized by dysentery and liver abscess. The physiopathology of hepatic lesions can be satisfactorily reproduced in the hamster animal model by the administration of trophozoites through the portal vein route. Hamsters were infected with radioactively labeled amoebas for analysis of liver abscess establishment and progression. The radioimaging of material from parasite origin and quantification of the number inflammation foci, with or without amoebas, described here provides the first detailed assessment of trophozoite survival and death during liver infection by E. histolytica. The massive death of trophozoites observed in the first hours postinfection correlates with the presence of a majority of inflammatory foci without parasites. A critical point for success of infection is reached after 12 h when the lowest number of trophozoites is observed. The process then enters a commitment phase during which parasites multiply and the size of the infection foci increases fast. The liver shows extensive areas of dead hepatocytes that are surrounded by a peripheral layer of parasites facing inflammatory cells leading to acute inflammation. Our results show that the host response promotes massive parasite death but also suggest also that this is a major contributor to the establishment of inflammation during development of liver abscess.

Krust B, Vienet R, Cardona A, Rougeot C, Jacotot E, Callebaut C, Guichard G, Briand JP, Grognet JM, Hovanessian AG, Edelman L: The anti-HIV pentameric pseudopeptide HB-19 is preferentially taken up in vivo by lymphoid organs where it forms a complex with nucleolin Proc Natl Acad Sci USA. 98(24):14090-14095 November (2001)

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Abstract
The HB-19 pseudopeptide 5[Kpsi(CH(2)N)PR]-TASP, psi(CH(2)N) for reduced peptide bond, is a specific inhibitor of HIV infection in different CD4(+) cell lines and in primary T-lymphocytes and macrophages. It blocks virus-particle attachment to permissive cells by binding and forming a stable complex with nucleolin expressed on the cell surface. Here, we have investigated the tissue distribution of the tritiated HB-19 by using beta-radio imager whole-body mapping in rats. A rapid, selective, and stable distribution and accumulation of the systematically administered HB-19 was demonstrated within the spleen, liver, bone, and kidney as soon as 5 min following its administration. No apparent uptake of HB-19 occurred in the brain and the muscle tissue. Interestingly and despite its rapid clearance from the blood, at 24 h postexposure a significant proportion of HB-19 was still recovered from target organs, of which 16-37% could be accounted for intact pseudopeptide. The elimination of HB-19 mainly occurred by renal glomerular filtration and most of the excreted radioactivity appeared to be HB-19 metabolites. Finally, injection of the biotin-labeled HB-19 pseudopeptide but not its control counterpart allowed the recovery of the HB-19-nucleolin complex from the liver, spleen, thymus, and bone marrow, thus indicating that the in vivo molecular target of HB-19 is surface nucleolin. Our results demonstrate the preferential uptake and stability of HB-19 in lymphoid organs that are the site of HIV propagation.

Vizler C, Bercovici N, Heurtier A, Pardigon N, Goude K, Bailly K, Combadière C, Liblau RS: Relative diabetogenic properties of islet-specific Tc1 and Tc2 cells in immunocompetent hosts J Immunol. 165(11):6314-6321 January (2001)

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Abstract
CD8(+) T cells are important effectors, as well as regulators, of organ-specific autoimmunity. Compared with Tc1-type CD8(+) cells, Tc2 cells have impaired anti-viral and anti-tumor effector functions, although no data are yet available on their pathogenic role in autoimmunity. Our aim was to explore the role of autoreactive Tc1 and Tc2 cells in autoimmune diabetes. We set up an adoptive transfer model in which the recipients were transgenic mice expressing influenza virus hemagglutinin (HA) specifically in their pancreatic ss islet cells (rat insulin promoter-HA mice) and islet-specific Tc1 and Tc2 cells were generated in vitro from HA-specific CD8(+) cells of TCR transgenic mice (CL4-TCR mice). One million Tc1 cells, differentiated in vitro in the presence of IL-12, transferred diabetes in 100% of nonirradiated adult rat insulin promoter-HA recipients; the 50% diabetogenic dose was 5 x 10(5). Highly polarized Tc2 cells generated in the presence of IL-4, IL-10, and anti-IFN-gamma mAb had a relatively low, but definite, diabetogenic potential. Thus, 5 x 10(6) Tc2 cells caused diabetes in 6 of 18 recipients, while the same dose of naive CD8(+) cells did not cause diabetes. Looking for the cause of the different diabetogenic potential of Tc1 and Tc2 cells, we found that Tc2 cells are at least as cytotoxic as Tc1 cells but their accumulation in the pancreas is slower, a possible consequence of differential chemokine receptor expression. The diabetogenicity of autoreactive Tc2 cells, most likely caused by their cytotoxic activity, precludes their therapeutic use as regulators of autoimmunity.

Rougeot C, Vienet R, Cardona A, Le Doledec L, Grognet JM, Rougeon F: Targets for SMR1-pentapeptide suggest a link between the circulating peptide and mineral transport Am J Physiol. 273(4 Pt 2):R1309-20 October (1997)

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Abstract
The submandibular rat 1 protein (SMR1) is selectively processed at pairs of basic amino acid residues in a tissue- and sex-specific manner. We have mapped peripheral targets for the final secretory maturation product of SMR1, the pentapeptide QHNPR, by examining in vivo the tissue distribution of the radiolabeled peptide using beta-radio imager whole body autoradiography. The characteristics of tissue uptake allowed specific binding sites at physiological peptide concentrations to be identified within the renal outer medulla, bone and dental tissue, glandular gastric mucosa, and pancreatic lobules. Direct evidence that pentapeptide binding sites are localized in selective portions of the male rat nephron, within the S3, S2, and S1 segments of the proximal tubules, was obtained. In bone tissue the pentapeptide exclusively accumulates within the trabecular bone remodeling unit, and in dental tissue it concentrates within the tubules of the dentinal rat incisor. In relation to male rat-specific behavioral characteristics, our data suggest that the circulating androgen-regulated SMR1-derived pentapeptide is primarily involved in the modulation of mineral balance between at least four systems: kidney, bone, tooth, and circulation.

Technical publications

Breskin A.: Advances in gas avalanche radiation detectors for biomedical applications Nucl. Instr. Meth A454, 26-39 January (2000)

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Breskin A.: Advances in gas avalanche radiation detectors for biomedical applications Nucl. Instr. Meth A454, 26-39 January (2000)

Abstract
Gas avalanche detectors are instruments of choice for radiation detection and localization in numerous elds of basic and applied research. Recent advances in detection techniques, involving multiplication and detection of single or a few charges deposited in gas media, or emitted from solid converters into gas, are described. The properties of radiation converters and associated advanced gas multipliers are discussed, with an accent on the recently introduced gas avalanche imaging photomultipliers. Applications in the elds of radiation damage studies to DNA, digital mammography and early detection of cancer tumors are presented