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Neurosciences

  • Kühbacher M, Bartel J, Hoppe B, Alber D, Bukalis G, Bräuer AU, Behne D, Kyriakopoulos A: The brain selenoproteome: priorities in the hierarchy and different levels of selenium homeostasis in the brain of selenium-deficient rats J Neurochem. 110(1):133-142 April (2009)

    > Abstract | Link to journal

    • Kühbacher M, Bartel J, Hoppe B, Alber D, Bukalis G, Bräuer AU, Behne D, Kyriakopoulos A: The brain selenoproteome: priorities in the hierarchy and different levels of selenium homeostasis in the brain of selenium-deficient rats J Neurochem. 110(1):133-142 April (2009)

    Abstract
    Abstract The application of radionuclides for the localization of essential trace elements in vivo and the characterization of their binding proteins is a story of intermittently made improvements of the techniques used for their detection. In this study we present the use of neutron activation analysis and different autoradiographic imaging methods including real-time digital autoradiography to reveal new insights in the hierarchy of selenium homeostasis. Selenoproteins containing the essential trace element selenium play important roles in the CNS. Although the CNS does not show the highest selenium concentration in the case of selenium-sufficient supply in comparison with other organs, it shows a high priority for selenium uptake and retention in the case of dietary selenium deficiency. To characterize the hierarchy of selenium supply in the brain, in vivo radiotracer labeling with (75)Se in rats with different selenium status was combined with autoradiographic detection of (75)Se in brain tissue sections and (75)Se-labeled selenoproteins after protein separation by two-dimensional gel electrophoresis. This study demonstrates significant differences in the uptake of (75)Se into the brain of rats with different selenium status. A brain region-specific uptake pattern of the radiotracer (75)Se in selenium-deficient rats could be revealed and the CSF was identified as a key part of the brain selenium homeostasis.

  • Lepagnol-Bestel AM, Maussion G, Boda B, Cardona A, Iwayama Y, Delezoide AL, Moalic JM, Muller D, Dean B, Yoshikawa T, Gorwood P, Buxbaum JD, Ramoz N, Simonneau M: SLC25A12 expression is associated with neurite outgrowth and is upregulated in the prefrontal cortex of autistic subjects Mol Psychiatry. 13(4):385-97 April (2008)

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    • Lepagnol-Bestel AM, Maussion G, Boda B, Cardona A, Iwayama Y, Delezoide AL, Moalic JM, Muller D, Dean B, Yoshikawa T, Gorwood P, Buxbaum JD, Ramoz N, Simonneau M: SLC25A12 expression is associated with neurite outgrowth and is upregulated in the prefrontal cortex of autistic subjects Mol Psychiatry. 13(4):385-97 April (2008)

    Abstract
    Autism is a neurodevelopmental disorder with a strong genetic component, probably involving several genes. Genome screens have provided evidence of linkage to chromosome 2q31-q33, which includes the SLC25A12 gene. Association between autism and single-nucleotide polymorphisms in SLC25A12 has been reported in various studies. SLC25A12 encodes the mitochondrial aspartate/glutamate carrier functionally important in neurons with high-metabolic activity. Neuropathological findings and functional abnormalities in autism have been reported for Brodmann's area (BA) 46 and the cerebellum. We found that SLC25A12 was expressed more strongly in the post-mortem brain tissues of autistic subjects than in those of controls, in the BA46 prefrontal cortex but not in cerebellar granule cells. SLC25A12 expression was not modified in brain subregions of bipolar and schizophrenic patients. SLC25A12 was expressed in developing human neuronal tissues, including neocortical regions containing excitatory neurons and neocortical progenitors and the ganglionic eminences that generate neocortical inhibitory interneurons. At mid-gestation, when gyri and sulci start to develop, SLC25A12 molecular gradients were identified in the lateral prefrontal and ventral temporal cortex. These fetal structures generate regions with abnormal activity in autism, including the dorsolateral prefrontal cortex (BA46), the pars opercularis of the inferior frontal cortex and the fusiform gyrus. SLC25A12 overexpression or silencing in mouse embryonic cortical neurons also modified dendrite length and the mobility of dendritic mitochondria. Our findings suggest that SLC25A12 overexpression may be involved in the pathophysiology of autism, modifying neuronal networks in specific subregions, such as the dorsolateral prefrontal cortex and fusiform gyrus, at both pre- and postnatal stages.

  • Nehlig A, Coles JA: Cellular pathways of energy metabolism in the brain: is glucose used by neurons or astrocytes? Glia 55(12):1238-50 April (2009)

    > Abstract | Link to journal

    • Nehlig A, Coles JA: Cellular pathways of energy metabolism in the brain: is glucose used by neurons or astrocytes? Glia 55(12):1238-50 April (2009)

    Abstract
    Most techniques presently available to measure cerebral activity in humans and animals, i.e. positron emission tomography (PET), autoradiography, and functional magnetic resonance imaging, do not record the activity of neurons directly. Furthermore, they do not allow the investigator to discriminate which cell type is using glucose, the predominant fuel provided to the brain by the blood. Here, we review the experimental approaches aimed at determining the percentage of glucose that is taken up by neurons and by astrocytes. This review is integrated in an overview of the current concepts on compartmentation and substrate trafficking between astrocytes and neurons. In the brain in vivo, about half of the glucose leaving the capillaries crosses the extracellular space and directly enters neurons. The other half is taken up by astrocytes. Calculations suggest that neurons consume more energy than do astrocytes, implying that astrocytes transfer an intermediate substrate to neurons. Experimental approaches in vitro on the honeybee drone retina and on the isolated vagus nerve also point to a continuous transfer of intermediate metabolites from glial cells to neurons in these tissues. Solid direct evidence of such transfer in the mammalian brain in vivo is still lacking. PET using [(18)F]fluorodeoxyglucose reflects in part glucose uptake by astrocytes but does not indicate to which step the glucose taken up is metabolized within this cell type. Finally, the sequence of metabolic changes occurring during a transient increase of electrical activity in specific regions of the brain remains to be clarified.

  • Kanekiyo T, Ban T, Aritake K, Huang ZL, Qu WM, Okazaki I, Mohri I, Murayama S, Ozono K, Taniike M, Goto Y, Urade Y: Lipocalin-type prostaglandin D synthase/Beta-trace is a major amyloid Beta-chaperone in human cerebrospinal fluid Proc Natl Acad Sci U S A. 104(15):6412-7 April (2007)

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    • Kanekiyo T, Ban T, Aritake K, Huang ZL, Qu WM, Okazaki I, Mohri I, Murayama S, Ozono K, Taniike M, Goto Y, Urade Y: Lipocalin-type prostaglandin D synthase/Beta-trace is a major amyloid Beta-chaperone in human cerebrospinal fluid Proc Natl Acad Sci U S A. 104(15):6412-7 April (2007)

    Abstract
    The conformational change in amyloid beta (Abeta) peptide from its monomeric form to aggregates is crucial in the pathogenesis of Alzheimer's disease (AD). In the healthy brain, some unidentified chaperones appear to prevent the aggregation of Abeta. Here we reported that lipocalin-type prostaglandin D synthase (L-PGDS)/beta-trace, the most abundant cerebrospinal fluid (CSF) protein produced in the brain, was localized in amyloid plaques in both AD patients and AD-model Tg2576 mice. Surface plasmon resonance analysis revealed that L-PGDS/beta-trace tightly bound to Abeta monomers and fibrils with high affinity (K(D) = 18-50 nM) and that L-PGDS/beta-trace recognized residues 25-28 in Abeta, which is the key region for its conformational change to a beta-sheet structure. The results of a thioflavin T fluorescence assay to monitor Abeta aggregation disclosed that L-PGDS/beta-trace inhibited the spontaneous aggregation of Abeta (1-40) and Abeta (1-42) within its physiological range (1-5 microM) in CSF. L-PGDS/beta-trace also prevented the seed-dependent aggregation of 50 microM Abeta with K(i) of 0.75 microM. Moreover, the inhibitory activity toward Abeta (1-40) aggregation in human CSF was decreased by 60% when L-PGDS/beta-trace was removed from the CSF by immunoaffinity chromatography. The deposition of Abeta after intraventricular infusion of Abeta (1-42) was 3.5-fold higher in L-PGDS-deficient mice and reduced to 23% in L-PGDS-overexpressing mice as compared with their wild-type levels. These data indicate that L-PGDS/beta-trace is a major endogenous Abeta-chaperone in the brain and suggest that the disturbance of this function may be involved in the onset and progression of AD. Our findings may provide a diagnostic and therapeutic approach for AD.

  • Riad M, Zimmer L, Rbah L, Watkins KC, Hamon M, Descarries L.: Acute treatment with the antidepressant fluoxetine internalizes 5-HT1A autoreceptors and reduces the in vivo binding of the PET radioligand [18F]MPPF in the nucleus raphe dorsalis of rat J Neurosci. 24(23):5420-6 January (2004)

    > Abstract | Link to journal

    • Riad M, Zimmer L, Rbah L, Watkins KC, Hamon M, Descarries L.: Acute treatment with the antidepressant fluoxetine internalizes 5-HT1A autoreceptors and reduces the in vivo binding of the PET radioligand [18F]MPPF in the nucleus raphe dorsalis of rat J Neurosci. 24(23):5420-6 January (2004)

    Abstract
    Because 5-HT1A receptors located on the soma dendrites of serotonin (5-HT) neurons normally mediate an inhibition of 5-HT firing and release, the desensitization of these autoreceptors is essential for obtaining an enhancement of 5-HT transmission after treatment with 5-HT reuptake inhibitors (SSRIs). We have demonstrated previously, using immunoelectron microscopy with specific 5-HT1A antibodies, that an internalization of 5-HT1A autoreceptors is associated with their desensitization in rats given a single dose of the 5-HT1A receptor agonist 8-hydroxy-2-(di-n-propylamino)tetralin. Here, we examined the subcellular distribution of 5-HT1A receptors in dendrites from nucleus raphe dorsalis (NRD) (autoreceptors) and hippocampus (heteroreceptors) after acute treatment with the antidepressant SSRI, fluoxetine (10 mg/kg, i.p.). In parallel experiments, the kinetics of in vivo binding of the 5-HT1A positron emission tomography radioligand 4,2-(methoxyphenyl)-1-[2-(N-2-pyridinyl)-p-fluorobenzamido]ethylpiperazine ([18F]MPPF) was measured in these two brain regions by means of stereotaxically implanted beta microprobes. One hour after treatment, there was a 36% decrease in 5-HT1A immunogold labeling of the plasma membrane of NRD dendrites, and a concomitant increase in their cytoplasmic labeling, without any change in hippocampal dendrites. In vivo binding of [18F]MPPF was reduced by 35% in NRD and unchanged in hippocampus. Both effects were blocked by pretreatment with the 5-HT1A receptor antagonist (N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridinyl) cyclohexane-carboxamide) (1 mg/kg, i.p.). In brain sections of NRD and hippocampus, [18F]MPPF autoradiographic labeling did not differ between fluoxetine- and saline-treated rats. These immunocytochemical results confirmed that internalization of 5-HT1A autoreceptors may account for their desensitization, and the microprobe results suggest that this prerequisite for antidepressant treatment efficacy could be amenable to brain imaging in humans.

  • Zimmer L, Riad M, Rbah L, Belkacem-Kahlouli A, Le Bars D, Renaud B, Descarries L: Toward brain imaging of serotonin 5-HT1A autoreceptor internalization Neuroimage 22(3):1421-6 July (2004)

    > Abstract | Link to journal

    • Zimmer L, Riad M, Rbah L, Belkacem-Kahlouli A, Le Bars D, Renaud B, Descarries L: Toward brain imaging of serotonin 5-HT1A autoreceptor internalization Neuroimage 22(3):1421-6 July (2004)

    Abstract
    Enhancing cerebral serotonin (5-hydroxytryptamine, 5-HT) neurotransmission is a common property of antidepressant treatments and the basis for their efficacy. 5-HT1A receptors located on the cell body and dendrites of 5-HT neurons (autoreceptors) play a key role in this regard. Because they normally mediate an inhibition of neuronal firing, their desensitization is a prerequisite to the delayed enhancement of 5-HT neurotransmission upon treatment with monoamine oxidase (MAOI) inhibitors or specific serotonin reuptake inhibitors (SSRI). Using beta-sensitive microprobes in vivo, we measured a significant decrease (-30%) in binding sites for the 5-HT1A PET radioligand [18F]MPPF associated with an equivalent reduction (-34%) in the cell surface density of 5-HT1A receptor immunoreactivity (internalization), in the nucleus raphe dorsalis (autoreceptors), but not hippocampus (heteroreceptors), of rats given a single dose of the specific 5-HT1A receptor agonist, 8-OH-DPAT (0.5 mg/kg, iv). This effect was completely blocked by pretreatment with the selective 5-HT1A antagonist WAY 100635. Having ruled out that this decreased density of [18F]MPPF binding in the nucleus raphe dorsalis of 8-OH-DPAT-treated rats resulted from a local blood flow effect, we obtained autoradiographic evidence indicating that the total amount of specific binding of [18F]MPPF in tissue sections was unaffected by the 8-OH-DPAT treatment in either NRD or hippocampus. It was therefore concluded that the internalization of 5-HT1A autoreceptors accounted for the decreased binding in vivo of [18F]MPPF in the nucleus raphe dorsalis of rats treated with 8-OH-DPAT. Thus, PET imaging might provide a mean to measure 5-HT1A receptor internalization in human brain and thus assess responsiveness to antidepressant treatment.

  • Véga C, Martiel JL, Drouhault D, Burckhart MF, Coles JA: Uptake of locally applied deoxyglucose, glucose and lactate by axons and Schwann cells of rat vagus nerve J Physiol. 546(Pt 2):551-64 January (2003)

    > Abstract | Link to journal

    • Véga C, Martiel JL, Drouhault D, Burckhart MF, Coles JA: Uptake of locally applied deoxyglucose, glucose and lactate by axons and Schwann cells of rat vagus nerve J Physiol. 546(Pt 2):551-64 January (2003)

    Abstract
    We asked whether, in a steady state, neurons and glial cells both take up glucose sufficient for their energy requirements, or whether glial cells take up a disproportionate amount and transfer metabolic substrate to neurons. A desheathed rat vagus nerve was held crossways in a laminar flow perfusion chamber and stimulated at 2 Hz. (14)C-labelled substrate was applied from a micropipette for 5 min over a < 0.6 mm band of the surface of the nerve. After 10-55 min incubation, the nerve was lyophilized and the longitudinal distribution of radioactivity measured. When the weakly metabolizable analogue of glucose, 2-deoxy-[U-(14)C]D-glucose (*DG), was applied, the profiles of the radioactivity broadened with time, reaching distances several times the mean length of the Schwann cells (0.32 mm; most of the Schwann cells are non-myelinating). The profiles were well fitted by curves calculated for diffusion in a single compartment, the mean diffusion coefficient being 463 +/- 34 microm(2) s(-1) (+/- S.E.M., n = 16). Applications of *DG were repeated in the presence of the gap junction blocker, carbenoxolone (100 microM). The profiles were now narrower and better fitted with two compartments. One compartment had a coefficient not significantly different from that in the absence of the gap junction blocker (axons), the other compartment had a coefficient of 204 +/- 24 microm(2) s(-1), n = 4. Addition of the gap junction blocker 18-alpha-glycyrrhetinic acid, or blocking electrical activity with TTX, also reduced longitudinal diffusion. Ascribing the compartment in which diffusion was reduced by these treatments to non-myelinating Schwann cells, we conclude that 78.0 +/- 3.6 % (n = 9) of the uptake of *DG was into Schwann cells. This suggests that there was transfer of metabolic substrate from Schwann cells to axons. Local application of [(14)C]glucose or [(14)C]lactate led to variable labelling along the length of the nerve, but with both substrates narrow peaks were often present at the application site; these were greatly reduced by subsequent treatment with amylase, a glycogen-degrading enzyme.

  • Bahi N, Friocourt G, Carrié A, Graham ME, Weiss JL, Chafey P, Fauchereau F, Burgoyne RD, Chelly J: IL1 receptor accessory protein like, a protein involved in X-linked mental retardation, interacts with Neuronal Calcium Sensor-1 and regulates exocytosis Hum Mol Genet. 12(12):1415-25 January (2003)

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    • Bahi N, Friocourt G, Carrié A, Graham ME, Weiss JL, Chafey P, Fauchereau F, Burgoyne RD, Chelly J: IL1 receptor accessory protein like, a protein involved in X-linked mental retardation, interacts with Neuronal Calcium Sensor-1 and regulates exocytosis Hum Mol Genet. 12(12):1415-25 January (2003)

    Abstract
    Previously, human genetics-based approaches allowed us to show that mutations in the IL-1 receptor accessory protein-like gene (IL1RAPL) are responsible for a non-specific form of X-linked mental retardation. This gene encodes a predicted protein of 696 amino acids that belongs to a novel class of the IL-1/Toll receptor family. In addition to the extracellular portion consisting of three Ig-like domains and the intracellular TIR domain characteristic of the IL-1/Toll receptor family, IL1RAPL contains a specific 150 amino acid carboxy terminus that has no significant homology with any protein of known function. In order to begin to elucidate the function of this IL-1/Toll receptor-like protein, we have assessed the effect of recombinant IL1RAPL on the binding affinity of type I IL-1R for its ligands IL-1alpha and beta and searched for proteins interacting with the specific carboxy terminus domain of IL1RAPL. Our results show that IL1RAPL is not a protein receptor for IL-1. In addition we present here the identification of Neuronal Calcium Sensor-1 (NCS-1) as an IL1RAPL interactor. Remarkably, although NCS-1 and its non-mammalian homologue, frequenin, are members of a highly conserved EF-hand Ca(2+) binding protein family, our data show that IL1RAPL interacts only with NCS-1 through its specific C-terminal domain. The functional relevance of IL1RAPL activity was further supported by the inhibitory effect on exocytosis in PC12 cells overexpressing IL1RAPL. Taken together, our data suggest that IL1RAPL may regulate calcium-dependent exocytosis and provide insight into the understanding of physiopathological mechanisms underlying cognitive impairment resulting from IL1RAPL dysfunction

  • Vollmayr B, Faust H, Lewicka S, Henn FA: Brain-derived-neurotrophic-factor (BDNF) stress response in rats bred for learned helplessness Mol Psychiatry. 6(4):471-4, 358 January (2001)

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  • Zemni R, Bienvenu T, Vinet MC, Sefiani A, Carrié A, Billuart P, McDonell N, Couvert P, Francis F, Chafey P, Fauchereau F, Friocourt G, des Portes V, Cardona A, Frints S, Meindl A, Brandau O, Ronce N, Moraine C, van Bokhoven H, Ropers HH, Sudbrak R, Kahn A, Fryns JP, Beldjord C, Chelly J: A new gene involved in X-linked mental retardation identified by analysis of an X;2 balanced translocation Nat Genet. 24(2):167-70 February (2000)

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  • Carrié A, Jun L, Bienvenu T, Vinet MC, McDonell N, Couvert P, Zemni R, Cardona A, Van Buggenhout G, Frints S, Hamel B, Moraine C, Ropers HH, Strom T, Howell GR, Whittaker A, Ross MT, Kahn A, Fryns JP, Beldjord C, Marynen P, Chelly J: A new member of the IL-1 receptor family highly expressed in hippocampus and involved in X-linked mental retardation Nat Genet. 23(1):25-31 April (1999)

    > Abstract | Link to journal

    • Oncology

  • Nejjari M, Kryza D, Poncet G, Roche C, Perek N, Chayvialle JA, Le Bars D, Scoazec JY, Janier M, Borson-Chazot F: In vitro and in vivo studies with [18F]fluorocholine on digestive tumoral cell lines and in an animal model of metastasized endocrine tumor Nucl Med Biol. 35(1):123-30 January (2008)

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    • Nejjari M, Kryza D, Poncet G, Roche C, Perek N, Chayvialle JA, Le Bars D, Scoazec JY, Janier M, Borson-Chazot F: In vitro and in vivo studies with [18F]fluorocholine on digestive tumoral cell lines and in an animal model of metastasized endocrine tumor Nucl Med Biol. 35(1):123-30 January (2008)

    Abstract
    PURPOSE: The aim of this study was to investigate (a) in vitro the relationship between [(18)F]fluorocholine ([(18)F]FCH) uptake and cell growth in endocrine cell lines and (b) in vivo the uptake of [(18)F]FCH by tumoral sites in an animal model of metastasized endocrine tumor. METHODS: In vitro studies were conducted on three endocrine and two nonendocrine digestive tumoral cell lines. The proliferative ratio was estimated using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. The uptake of [(18)F]FCH and that of [(18)F]fluorodeoxyglucose ([(18)F]FDG) were measured before and after cytotoxic therapy. [(18)F]FCH biodistribution was studied in nude mice and in an endocrine xenografted mice model. RESULTS: The [(18)F]FCH uptake in tumoral cell lines was related to their proliferative capacities as measured by the MTT assay in basal conditions. After cytotoxic therapy, the IC(50) values calculated with the [(18)F]FCH incorporation test were very close to those determined with the MTT assay. Biodistribution studies showed that [(18)F]FCH was predominantly concentrated in the liver and kidney of nude mice. In the STC-1 xenografted animal model, the uptake of [(18)F]FCH in the primary tumor was only 1.1%. On autoradiography and micro-positron emission tomography, there was no uptake of [(18)F]FCH in liver metastases but there was a significant uptake of [(18)F]FDG. CONCLUSIONS: In vitro studies suggested that the incorporation of [(18)F]FCH in endocrine tumor cell lines was related to their growth capacities; however, in vivo studies conducted in an endocrine xenografted animal model showed an uptake of [(18)F]FCH in hepatic metastases lower than that in normal liver cells. An influence of the microenvironment or a competition phenomenon for [(18)F]FCH uptake between normal liver and endocrine tumor cells cannot be excluded.

  • Drecoll E, Gaertner FC, Miederer M, Blechert B, Vallon M, et al.: Treatment of Peritoneal Carcinomatosis by Targeted Delivery of the Radio-Labeled Tumor Homing Peptide 213Bi-DTPA-[F3]2 into the Nucleus of Tumor Cells PLoS ONE 4(5): e5715 May (2009)

    > Abstract | Link to journal

    • Drecoll E, Gaertner FC, Miederer M, Blechert B, Vallon M, et al.: Treatment of Peritoneal Carcinomatosis by Targeted Delivery of the Radio-Labeled Tumor Homing Peptide 213Bi-DTPA-[F3]2 into the Nucleus of Tumor Cells PLoS ONE 4(5): e5715 May (2009)

    Abstract
    BACKGROUND: Alpha-particle emitting isotopes are effective novel tools in cancer therapy, but targeted delivery into tumors is a prerequisite of their application to avoid toxic side effects. Peritoneal carcinomatosis is a widespread dissemination of tumors throughout the peritoneal cavity. As peritoneal carcinomatosis is fatal in most cases, novel therapies are needed. F3 is a tumor homing peptide which is internalized into the nucleus of tumor cells upon binding to nucleolin on the cell surface. Therefore, F3 may be an appropriate carrier for alpha-particle emitting isotopes facilitating selective tumor therapies. PRINCIPAL FINDINGS: A dimer of the vascular tumor homing peptide F3 was chemically coupled to the alpha-emitter (213)Bi ((213)Bi-DTPA-[F3](2)). We found (213)Bi-DTPA-[F3](2) to accumulate in the nucleus of tumor cells in vitro and in intraperitoneally growing tumors in vivo. To study the anti-tumor activity of (213)Bi-DTPA-[F3](2) we treated mice bearing intraperitoneally growing xenograft tumors with (213)Bi-DTPA-[F3](2). In a tumor prevention study between the days 4-14 after inoculation of tumor cells 6x1.85 MBq (50 microCi) of (213)Bi-DTPA-[F3](2) were injected. In a tumor reduction study between the days 16-26 after inoculation of tumor cells 6x1.85 MBq of (213)Bi-DTPA-[F3](2) were injected. The survival time of the animals was increased from 51 to 93.5 days in the prevention study and from 57 days to 78 days in the tumor reduction study. No toxicity of the treatment was observed. In bio-distribution studies we found (213)Bi-DTPA-[F3](2) to accumulate in tumors but only low activities were found in control organs except for the kidneys, where (213)Bi-DTPA-[F3](2) is found due to renal excretion. CONCLUSIONS/SIGNIFICANCE: In conclusion we report that (213)Bi-DTPA-[F3](2) is a novel tool for the targeted delivery of alpha-emitters into the nucleus of tumor cells that effectively controls peritoneal carcinomatosis in preclinical models and may also be useful in oncology.

  • Kriehuber R, Simkó M: Apoptosis induction and micronucleus formation after exposure to the Auger electron emitter zinc-65 in a human cell line Acta Oncol. 39(6):699-706 January (2000)

    > Abstract

    Kriehuber R, Simkó M: Apoptosis induction and micronucleus formation after exposure to the Auger electron emitter zinc-65 in a human cell line Acta Oncol. 39(6):699-706 January (2000)

    Abstract
    Induction of apoptosis and micronucleus formation has been studied in a transformed human squamous cell carcinoma cell line (SCL-II) after exposure to the Auger electron emitter Zinc-65 (65Zn) and after external low-LET radiation. Exposure to non-radioactive Zn and unirradiated cells served as controls. Studies on the cellular uptake of 65Zn2+ have been carried out in vitro and conventional dosimetric models have been applied to derive the absorbed radiation dose. Auger electrons, generated during decay of 65Zn2+, are strong inducers of micronuclei as well as of apoptosis, in comparison to external low-LET irradiation. The relative biological effectiveness has been determined and was found to be in the range of 1.2-2.7 for the two investigated biological endpoints, depending on which mathematical model for describing the dose-effect curves was used. A non-uniform distribution of intracellular Zn2 + was observed, showing a strong signal in the perinuclear region. We conclude that separate radiation weighting factors for Auger electrons should be established depending on the nuclide and its ability to interact with the DNA (e.g. 65Zn by Zinc-finger proteins).

  • Senekowitsch-Schmidtke R, Schuhmacher C, Becker KF, Nikula TK, Seidl C, Becker I, Miederer M, Apostolidis C, Adam C, Huber R, Kremmer E, Fischer K, Schwaiger M.: Highly specific tumor binding of a 213Bi-labeled monoclonal antibody against mutant E-cadherin suggests its usefulness for locoregional alpha-radioimmunotherapy of diffuse-type gastric cancer. Cancer Res. 61(7):2804-8 January (2001)

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  • Roesch Ely M, Nees M, Karsai S, Mägele I, Bogumil R, Vorderwülbecke S, Ruess A, Dietz A, Schnölzer M, Bosch FX.: Transcript and proteome analysis reveals reduced expression of calgranulins in head and neck squamous cell carcinoma. Eur J Cell Biol. 84(2-3):431-44 March (2005)

    > Abstract

    Roesch Ely M, Nees M, Karsai S, Mägele I, Bogumil R, Vorderwülbecke S, Ruess A, Dietz A, Schnölzer M, Bosch FX.: Transcript and proteome analysis reveals reduced expression of calgranulins in head and neck squamous cell carcinoma. Eur J Cell Biol. 84(2-3):431-44 March (2005)

    Abstract
    The calcium-binding proteins of the S100 and the annexin protein families have been implicated in a variety of important physiological functions including membrane remodeling, calcium-related intracellular signaling, cytoskeleton dynamics, tissue homeostasis, and formation of the cornified envelope in differentiating keratinocytes. Deregulated expression of members of these families has been reported in different types of neoplasia and other diseases, but the results were not consistent. Here we have applied a combination of cDNA microarrays, quantitative reverse transcriptase-PCR (qRT-PCR) and surface enhanced laser desorption ionisation-time of flight mass spectrometry (SELDI-TOF MS) to study differential expression of these genes in head and neck squamous cell carcinoma (HNSCC). The calgranulins A and B and annexins 1 and 2 were found to be down-regulated in HNSCC, compared with normal mucosa, at both the mRNA and protein level. Upon validation of the differential gene expression by tissue microarray immunohistochemistry, we detected novel expression patterns of calgranulins A and B both in normal mucosa as well as in HNSCC. In contrast to squamous cancer of skin and other cancers in which the calgranulins were found to be up-regulated, most HNSCC showed reduced and widely deranged staining patterns including heterogeneous nuclear, cytoplasmic and membranous staining, and even enhanced staining in the tumor stroma. These observations suggest that the normal function of the calgranulins A and B in mucosa might be different from that in skin.

  • Kriehuber R, Riedling M, Simkó M, Weiss DG: Cytotoxicity, genotoxicity and intracellular distribution of the Auger electron emitter (65)Zn in two human cell lines Radiat Environ Biophys. 43(1):15-22 January (2004)

    > Abstract | Link to journal

    • Kriehuber R, Riedling M, Simkó M, Weiss DG: Cytotoxicity, genotoxicity and intracellular distribution of the Auger electron emitter (65)Zn in two human cell lines Radiat Environ Biophys. 43(1):15-22 January (2004)

    Abstract
    Cell survival, induction of apoptosis, and micronucleus formation have been examined in non-transformed human amnion fluid fibroblast-like (AFFL) cells and in a human squameous cell carcinoma (SCL-II) cell line after exposure to the Auger electron emitter (65)Zn and after external low-LET radiation. Cellular uptake and subcellular distribution of (65)Zn(2+) were studied in vitro and the absorbed radiation dose was calculated applying analytical dosimetry models. Auger electrons generated during decay of (65)Zn induced a prominent decrease in cell survival and increased the levels of apoptotic as well as micronucleated cells when compared to external low-LET irradiation. Relative biological effectiveness has been determined for cell survival (RBE approximately 4), micronucleus formation (RBE approximately 2) and apoptosis induction (RBE approximately 5-8) in SCL-II cells and for micronucleus formation (RBE approximately 4-5) and apoptosis induction (RBE approximately 6-10) in AFFL cells, respectively. This demonstrates a general enhanced biological effectiveness of (65)Zn in both investigated cell lines when compared to external low-LET radiation. The distribution pattern of intracellular Zn(2+) was found to be non-uniform, showing enhanced amounts of Zn(2+) in the perinuclear region and low amounts inside the cell nucleus, suggesting a major energy deposition close to the nuclear envelope.

    Marine geochemistry

  • Treude T, Orphan V, Knittel K, Gieseke A, House CH, Boetius A.: Consumption of methane and CO2 by methanotrophic microbial mats from gas seeps of the anoxic Black Sea Appl Environ Microbiol. 73(7):2271-83 April (2007)

    > Abstract | Link to journal

    • Treude T, Orphan V, Knittel K, Gieseke A, House CH, Boetius A.: Consumption of methane and CO2 by methanotrophic microbial mats from gas seeps of the anoxic Black Sea Appl Environ Microbiol. 73(7):2271-83 April (2007)

    Abstract
    The deep anoxic shelf of the northwestern Black Sea has numerous gas seeps, which are populated by methanotrophic microbial mats in and above the seafloor. Above the seafloor, the mats can form tall reef-like structures composed of porous carbonate and microbial biomass. Here, we investigated the spatial patterns of CH(4) and CO(2) assimilation in relation to the distribution of ANME groups and their associated bacteria in mat samples obtained from the surface of a large reef structure. A combination of different methods, including radiotracer incubation, beta microimaging, secondary ion mass spectrometry, and catalyzed reporter deposition fluorescence in situ hybridization, was applied to sections of mat obtained from the large reef structure to locate hot spots of methanotrophy and to identify the responsible microbial consortia. In addition, CO(2) reduction to methane was investigated in the presence or absence of methane, sulfate, and hydrogen. The mat had an average delta(13)C carbon isotopic signature of -67.1 per thousand, indicating that methane was the main carbon source. Regions dominated by ANME-1 had isotope signatures that were significantly heavier (-66.4 per thousand +/- 3.9 per thousand [mean +/- standard deviation; n = 7]) than those of the more central regions dominated by ANME-2 (-72.9 per thousand +/- 2.2 per thousand; n = 7). Incorporation of (14)C from radiolabeled CH(4) or CO(2) revealed one hot spot for methanotrophy and CO(2) fixation close to the surface of the mat and a low assimilation efficiency (1 to 2% of methane oxidized). Replicate incubations of the mat with (14)CH(4) or (14)CO(2) revealed that there was interconversion of CH(4) and CO(2.) The level of CO(2) reduction was about 10% of the level of anaerobic oxidation of methane. However, since considerable methane formation was observed only in the presence of methane and sulfate, the process appeared to be a rereaction of anaerobic oxidation of methane rather than net methanogenesis.

  • Cook PLM, Røy H: Advective relief of CO2 limitation in microphytobenthos in highly productive sandy sediments Limnol. Oceanogr 51(4):1594–1601 January (2006)

    > Abstract | Link to journal

    • Cook PLM, Røy H: Advective relief of CO2 limitation in microphytobenthos in highly productive sandy sediments Limnol. Oceanogr 51(4):1594–1601 January (2006)

    Abstract
    Following field observations of increased photosynthesis at increased rates of sediment flushing in sandy sediments, we conducted a series of laboratory experiments to elucidate the mechanism behind these observations. Column experiments in which water was pumped though sand at rates ranging from 0 to 613 L m22 d21 showed that carbon (C) fixation, as measured using carbon-14 (14C) incorporation, increased from 6.4 to 8.6 mmol m22 h21 with increasing rates of flushing. Bottle incubations showed that the addition of inorganic nutrients [ammonium ion (NHþ4), inorganic phosphate (HPO24), silicic acid Si(OH)4] did not stimulate C fixation over short-term incubations. Microprofiles of pH showed that the pH within the photic zone increased to 8.9, reducing free carbon dioxide (CO2) concentrations to ,0.5 mmol L21. Further bottle incubations, where pH and total inorganic carbon (TCO2) were manipulated, showed that high pH (9.6) did not affect photosynthesis if free CO2 was present at concentrations of 10 mmol L21, suggesting a direct effect of low free CO2 concentrations. 14C fixation profiles at a resolution of 100 mm recorded by b-radiation imaging showed that while the depth specific maximum rates of C fixation were the same under both diffusive and advective (flushed) conditions, the integrated rates of photosynthesis were highest under flushed conditions because of a thickening of the photosynthetic zone. We conclude that advective pore-water transport can enhance benthic photosynthesis in shallow permeable sand sediments by counteracting CO2 limitation.

  • Ludwig R, Al-Horani FA, De Beer D, Jonkers HM: Photosynthesis-controlled calcification in a hypersaline microbial mat Limnology and Oceanography 50(6):1836-1843 November (2005)

    > Abstract | Link to journal

    • Ludwig R, Al-Horani FA, De Beer D, Jonkers HM: Photosynthesis-controlled calcification in a hypersaline microbial mat Limnology and Oceanography 50(6):1836-1843 November (2005)

    Abstract
    We investigated the hypothesis that sulfate reduction rather than oxygenic photosynthesis promotes calcification in a hypersaline microbial mat by increasing the ion concentration product: Ca2+ CO32-. Pore-water calcium concentration profiles directly measured with microsensors show that calcium concentration in the photic zone decreased in illuminated mats and increased slightly in dark mats. High pH values in the photic zone of illuminated mats resulted in higher carbonate concentrations 2.25 mmol/L than in dark mats 0.75 mmol/L although the dissolved inorganic carbon (DIC) pore-water concentration in the former was much lower (5.9 mmol/L) than in the latter 9.9 mmol/L. The pH-induced rise in carbonate concentration in the light was the main factor influencing the ICP, while changes in Ca2+ concentration played a subsidiary role. Sulfate reduction did not result in a net pH increase in these mats, as rates in the photic zone were comparable between illuminated and dark mats (4 and 5 nmol cm-2 h-1, respectively), and pH increased in illuminated mats but not in dark mats. Calcium carbonate precipitation in the photic zone of these hypersaline mats is primarily controlled by photosynthesis-induced pH and carbonate concentration increases. However, heterotrophic bacteria, including sulfate reducers, play an important complementary role in calcification because they maintain high concentrations of DIC in the mat pore water

  • Michaelis W, Seifert R, Nauhaus K, Treude T, Thiel V, Blumenberg M, Knittel K, Gieseke A, Peterknecht K, Pape T, Boetius A, Amann R, Jørgensen BB, Widdel F, Peckmann J, Pimenov NV, Gulin MB: Microbial Reefs in the Black Sea Fueled by Anaerobic Oxidation of Methane Science 297(5583):1013-5 January (2002)

    > Abstract | Link to journal

    • Physiology

  • Reuter S, Schnöckel U, Schröter R, Schober O, Pavenstädt H, Schäfers M, Gabriëls G, Schlatter E: Non-invasive imaging of acute renal allograft rejection in rats using small animal F-FDG-PET PLoS One 4(4):e5296 April (2009)

    > Abstract | Link to journal

    • Reuter S, Schnöckel U, Schröter R, Schober O, Pavenstädt H, Schäfers M, Gabriëls G, Schlatter E: Non-invasive imaging of acute renal allograft rejection in rats using small animal F-FDG-PET PLoS One 4(4):e5296 April (2009)

    Abstract
    BACKGROUND: At present, renal grafts are the most common solid organ transplants world-wide. Given the importance of renal transplantation and the limitation of available donor kidneys, detailed analysis of factors that affect transplant survival are important. Despite the introduction of new and effective immunosuppressive drugs, acute cellular graft rejection (AR) is still a major risk for graft survival. Nowadays, AR can only be definitively by renal biopsy. However, biopsies carry a risk of renal transplant injury and loss. Most important, they can not be performed in patients taking anticoagulant drugs. METHODOLOGY/PRINCIPAL FINDINGS: We present a non-invasive, entirely image-based method to assess AR in an allogeneic rat renal transplantation model using small animal positron emission tomography (PET) and (18)F-fluorodeoxyglucose (FDG). 3 h after i.v. injection of 30 MBq FDG into adult uni-nephrectomized, allogeneically transplanted rats, tissue radioactivity of renal parenchyma was assessed in vivo by a small animal PET-scanner (post operative day (POD) 1,2,4, and 7) and post mortem dissection. The mean radioactivity (cps/mm(3) tissue) as well as the percent injected dose (%ID) was compared between graft and native reference kidney. Results were confirmed by histological and autoradiographic analysis. Healthy rats, rats with acute CSA nephrotoxicity, with acute tubular necrosis, and syngeneically transplanted rats served as controls. FDG-uptake was significantly elevated only in allogeneic grafts from POD 1 on when compared to the native kidney (%ID graft POD 1: 0.54+/-0.06; POD 2: 0.58+/-0.12; POD 4: 0.81+/-0.06; POD 7: 0.77+/-0.1; CTR: 0.22+/-0.01, n = 3-28). Renal FDG-uptake in vivo correlated with the results obtained by micro-autoradiography and the degree of inflammatory infiltrates observed in histology. CONCLUSIONS/SIGNIFICANCE: We propose that graft FDG-PET imaging is a new option to non-invasively, specifically, early detect, and follow-up acute renal rejection. This method is potentially useful to improve post-transplant rejection monitoring.

  • Chollet C, Labrugére C, Durrieu MC: Impact of RGD peptide density grafted onto Poly(ethylene terephthalate) on MC3T3 cell attachment Conf Proc IEEE Eng Med Biol Soc. 5123-6 August (2007)

    > Abstract | Link to journal

  • Lattmann T, Shaw S, Münter K, Vetter W, Barton M.: Anatomically distinct activation of endothelin-3 and the L-arginine/nitric oxide pathway in the kidney with advanced aging Biochem Biophys Res Commun 327(1):234-41 February (2005)

    > Abstract | Link to journal

    • Lattmann T, Shaw S, Münter K, Vetter W, Barton M.: Anatomically distinct activation of endothelin-3 and the L-arginine/nitric oxide pathway in the kidney with advanced aging Biochem Biophys Res Commun 327(1):234-41 February (2005)

    Abstract
    Aging is associated with spontaneous degenerative changes of renal function and structure. The aim of this study was to determine changes of the endothelin (ET) system and NO tissue bioactivity during the physiological aging process. Renal protein expression of ET-1 and ET-3, ETA, and ETB receptor mRNA expression, ET receptor binding and distribution, and tissue NO metabolite content were determined in adult, middle-aged, and senescent normotensive female Wistar rats. In senescent animals, medullary ET-3 content increased 3.4-fold (p<0.05 vs. adult), whereas aging did not affect ET-3 levels in the cortex. Local NO bioavailability, determined by NO metabolite tissue measurements, decreased in the cortex only. ET receptor binding capacity--predominantly due to ETB receptor binding--was lower in medulla than in cortex. Aging had no effect on ET-1 binding capacity or ET receptor distribution, whereas with advanced age gene expression of both receptors decreased. In conclusion, aging causes distinctive expressional changes of the renal endothelin system in otherwise healthy rats. The pronounced increase of endothelin-3 in the renal medulla is associated with preservation of local NO metabolite levels, changes not observed in the cortex. These findings could be important for pathologies and possibly therapy associated with renal aging.

  • Moussy Y, Dungel P, Hersh L: Diffusion of [3H]dexamethasone in rat subcutaneous slices after injection measured by digital autoradiography Biotechnol Prog. 22(6):1715-9 November (2006)

    > Abstract | Link to journal

    • Dermatology

  • Michelet JF, Gautier B, Gaillard O, Bernard BA, Benech F.: Human hair follicle pigmentary unit as a direct target for modulators of melanogenesis, as studied by [14C]-2-Thiouracil incorporation Experimental Dermatology 18(4):414-6 April (2009)

    > Abstract | Link to journal

  • Gautier B, Bernard BA: On the Use of Micro-Imager® to Directly Visualize Drug Distribution in Human Skin Skin Pharmacol Appl Skin Physiol 2001;14(Suppl.1):41-45 January (2001)

    > Abstract | Link to journal

    • Cardiovascular Research

  • Higuchi T, Bengel FM, Seidl S, Watzlowik P, Kessler H, Hegenloh R, Reder S, Nekolla SG, Wester HJ, Schwaiger M: Assessment of {alpha}v{beta}3 integrin expression after myocardial infarction by positron emission tomography Cardiovascular Research 78(2):395-403 May (2008)

    > Abstract | Link to journal

    • Higuchi T, Bengel FM, Seidl S, Watzlowik P, Kessler H, Hegenloh R, Reder S, Nekolla SG, Wester HJ, Schwaiger M: Assessment of {alpha}v{beta}3 integrin expression after myocardial infarction by positron emission tomography Cardiovascular Research 78(2):395-403 May (2008)

    Abstract
    Aims: The purpose of this study was to determine the feasibility of a new positron emission tomography (PET) imaging approach using an 18F-labelled {alpha}vß3 integrin antagonist (18F-Galacto-RGD) to monitor the integrin expression after myocardial infarction. Methods and results: Male Wister rats were subjected to 20 min transient left coronary artery occlusion followed by reperfusion. Autoradiographic analysis and in vivo PET imaging were used to determine myocardial 18F-Galacto-RGD uptake at different time points following reperfusion.
    Results: PET imaging and autoradiography demonstrated no significant focal myocardial 18F-Galacto-RGD uptake in non-operated control rats and at day 1 after reperfusion. However, focal accumulation in the infarct area started at day 3 (uptake ratio = 1.91 ± 0.22 vs. remote myocardium), peaked between 1 (3.43 ± 0.57) and 3 weeks (3.43 ± 0.95), and decreased to 1.96 ± 0.40 at 6 months after reperfusion. Pretreatment with {alpha}vß3 integrin antagonist c(-RGDfV-) significantly decreased tracer uptake, indicating the specificity of tracer uptake. The time course of focal tracer uptake paralleled vascular density as measured by CD31 immunohistochemical analysis.
    Conclusion: Regional 18F-Galacto-RGD accumulation suggests up-regulation of {alpha}vß3 integrin expression after myocardial infarction, which peaks between 1 and 3 weeks and remains detectable until 6 months after reperfusion. This new PET tracer is promising for the monitoring of myocardial repair processes.
    KEYWORDS Angiogenesis; Infarction; Ischaemia; Reperfusion; Endothelial receptors

  • Riou LM, Broisat A, Lartizien C, Toufektsian MC, Maitrejean S, Janier M, Vanzetto G, Fagret D, Ghezzi C: Assessment of non-reperfused and reperfused myocardial infarction using diffusible or deposited radiolabelled perfusion imaging agents Eur J Nucl Med Mol Imaging 34(3):330-7 March (2007)

    > Abstract | Link to journal

    • Riou LM, Broisat A, Lartizien C, Toufektsian MC, Maitrejean S, Janier M, Vanzetto G, Fagret D, Ghezzi C: Assessment of non-reperfused and reperfused myocardial infarction using diffusible or deposited radiolabelled perfusion imaging agents Eur J Nucl Med Mol Imaging 34(3):330-7 March (2007)

    Abstract
    PURPOSE: Incomplete microvascular reperfusion is often observed in patients undergoing thrombolytic therapy or angioplasty for acute myocardial infarction and has important prognostic implications. We compared the myocardial uptake of diffusible ((201)Tl) and deposited ((99m)TcN-NOET) perfusion imaging agents in the setting of experimental infarction. METHODS: Rats were subjected to permanent coronary occlusion (OCC, n=10) or to 45-min occlusion and reperfusion (REP, n=17). Seven days later, the tracers were co-injected and the animals were euthanised 15 min (all ten rats in the OCC group and 12 rats in the REP group) or 120 min (five rats from the REP group, euthanised at this time point to evaluate any redistribution of the tracers: REP-RED group) afterwards. Infarct size determination and (99m)TcN-NOET/(201)Tl ex vivo imaging were performed. Regional flow and tissue oedema were quantified using radioactive microspheres and (99m)Tc-DTPA, respectively. RESULTS: (99m)TcN-NOET and (201)Tl defect magnitudes were similar in OCC animals (0.11+/-0.01 vs 0.13+/-0.01). In REP animals, (201)Tl defect magnitude (0.25+/-0.02) was significantly lower than the magnitude of (99m)TcN-NOET and flow defects (0.14+/-0.03 and 0.17+/-0.01, respectively; p<0.05), despite the lack of (201)Tl redistribution (REP-RED animals). (99m)Tc-DTPA indicated the presence of oedema in the reperfused area. Blood distribution studies showed that, unlike (99m)TcN-NOET, (201)Tl plasma activity was mostly unbound to plasma proteins. CONCLUSION: (99m)TcN-NOET and (201)Tl delineated the non-viable area in chronic non-reperfused and reperfused myocardial infarction. The significantly decreased (201)Tl defect in reperfused infarction was likely due to partial diffusion of the tracer from the plasma into the oedema present in the infarcted area. Deposited perfusion tracers might be better suited than diffusible agents for the assessment of regional flow following reperfusion of myocardial infarction.

  • Maskali F, Poussier S, Marie PY, Tran N, Antunes L, Olivier P, Plenat F, Maîtrejean S, Zannad F, Karcher G: High-resolution simultaneous imaging of SPECT, PET, and MRI tracers on histologic sections of myocardial infarction J Nucl Cardiol 12(2):229-30 March (2005)

    Microbiology

  • Gieseke A, Nielsen JL, Amann R, Nielsen PH, de Beer D: In situ substrate conversion and assimilation by nitrifying bacteria in a model biofilm Environ Microbiol. 7(9):1392-404 September (2005)

    > Abstract | Link to journal

    • Gieseke A, Nielsen JL, Amann R, Nielsen PH, de Beer D: In situ substrate conversion and assimilation by nitrifying bacteria in a model biofilm Environ Microbiol. 7(9):1392-404 September (2005)

    Abstract
    Local nitrification and carbon assimilation activities were studied in situ in a model biofilm to investigate carbon yields and contribution of distinct populations to these activities. Immobilized microcolonies (related to Nitrosomonas europaea/eutropha, Nitrosomonas oligotropha, Nitrospira sp., and to other Bacteria) were incubated with [14C]-bicarbonate under different experimental conditions. Nitrifying activity was measured concomitantly with microsensors (oxygen, ammonium, nitrite, nitrate). Biofilm thin sections were subjected to fluorescence in situ hybridization (FISH), microautoradiography (MAR), and local quantification of [14C]-bicarbonate uptake (beta microimaging). Nitrifying activity and tracer assimilation were restricted to a surface layer of different thickness in the various experiments (substrate or oxygen limitation). Excess oxygen uptake under all conditions revealed heterotrophic activity fuelled by decay or excretion products during active nitrification. Depth limits and intensity of tracer incorporation profiles were in agreement with ammonia-oxidation activity (measured with microsensors), and distribution of incorporated tracer (detected with MAR). Microautoradiography revealed a sharp individual response of distinct populations in terms of in-/activity depending on the (local) environmental conditions within the biofilm. Net in situ carbon yields on N, expressed as e- equivalent ratios, varied between 0.005 and 0.018, and, thus, were in the lower range of data reported for pure cultures of nitrifiers.

  • Gissot M, Refour P, Briquet S, Boschet C, Coupé S, Mazier D, Vaquero C: Transcriptome of 3D7 and its gametocyte-less derivative F12 Plasmodium falciparum clones during erythrocytic development using a gene-specific microarray assigned to gene regulation, cell cycle and transcription factors Gene 341:267-77 October (2004)

    > Abstract | Link to journal

    • Gissot M, Refour P, Briquet S, Boschet C, Coupé S, Mazier D, Vaquero C: Transcriptome of 3D7 and its gametocyte-less derivative F12 Plasmodium falciparum clones during erythrocytic development using a gene-specific microarray assigned to gene regulation, cell cycle and transcription factors Gene 341:267-77 October (2004)

    Abstract
    During the complex life cycle of Plasmodium falciparum, through mosquito and human, the erythrocytic cycle is responsible for malarial disease and transmission. The regulation of events that occur during parasite development, such as proliferation and differentiation, implies a fine control of transcriptional activities that in turn governs the expression profiles of sets of genes. Pathways that underline gametocyte commitment are yet poorly understood even though kinases and transcription factors have been assumed to play a crucial role in this event. In order to understand the molecular mechanisms controlling the variation of gene expression profiles that might participate in early gametocytogenesis, the transcriptome of two clones, 3D7 and its gametocyte-less derivative F12, was compared at five time points of the erythrocytic asexual development. We have used a thematic DNA microarray containing 150 PCR fragments, representative of P. falciparum genes involved in signal transduction, cell cycle and transcriptional regulation. We identified several genes eliciting different expression profiles among which some implicated in gene regulation or encoding putative transcription factors. The differential expression of transcription factor and kinase transcripts observed in the two clones may enlighten genes that might have a role in impairment of the early gametocytogenesis of the F12 clone.

  • Salin H, Vujasinovic T, Mazurie A, Maitrejean S, Menini C, Mallet J, Dumas S: A novel sensitive microarray approach for differential screening using probes labelled with two different radioelements Nucleic Acids Res. 30(4):e17 February (2002)

    > Abstract | Link to journal

    • Salin H, Vujasinovic T, Mazurie A, Maitrejean S, Menini C, Mallet J, Dumas S: A novel sensitive microarray approach for differential screening using probes labelled with two different radioelements Nucleic Acids Res. 30(4):e17 February (2002)

    Abstract
    We have developed a novel microarray approach for differential screening using probes labelled with two different radioelements. The complementary DNAs from the reverse transcription of mRNAs from two different biological samples were labelled with radioelements of significantly different energies (3H and 35S or 33P). Radioactive images corresponding to the expressed genes were acquired with a MicroImager, a real time, high resolution digital autoradiography system. An algorithm was used to process the data such that the initially acquired radioactive image was filtered into two subimages, each representative of the hybridisation result specific for one probe. The simultaneous screening of gene expression in two different biological samples requires <100 ng mRNA without any amplification. In such conditions, the technique is sensitive enough to directly quantify the amount of mRNA even when present in small amounts: 10(7) molecules in the probe as assessed with an added control sequence and 2 x 10(5) molecules with an endogenous tyrosine hydroxylase mRNA. This novel technique of double radioactive labelling on a microarray is thus suitable for the comparison of gene expression in two different biological samples available in only small quantities. Consequently, it has great potential for various biological fields, such as neuroscience.

  • 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):3208-15 June (2002)

    > Abstract | Link to journal

    • 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):3208-15 June (2002)

    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):14090-5 November (2001)

    > Abstract | Link to journal

    • 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):14090-5 November (2001)

    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.

  • Salin H, Maitrejean S, Mallet J, Dumas S: Sensitive and quantitative co-detection of two mRNA species by double radioactive in situ hybridization J Histochem Cytochem. 48(12):1587-92 April (2000)

    > Abstract | Link to journal

    • Developmental biology

  • Al Halabiah H, Delezoide AL, Cardona A, Moalic JM, Simonneau M: Expression pattern of NOGO and NgR genes during human development Gene Expr Patterns 5(4):561-8 April (2005)

    > Abstract | Link to journal

  • Streck RD, Kumpf SW, Ozolins TR, Stedman DB: Rat embryos express transcripts for cyclooxygenase-1 and carbonic anhydrase-4, but not for cyclooxygenase-2, during organogenesis Birth Defects Res B Dev Reprod Toxicol. 68(1):57-69 February (2003)

    > Abstract | Link to journal

    • Streck RD, Kumpf SW, Ozolins TR, Stedman DB: Rat embryos express transcripts for cyclooxygenase-1 and carbonic anhydrase-4, but not for cyclooxygenase-2, during organogenesis Birth Defects Res B Dev Reprod Toxicol. 68(1):57-69 February (2003)

    Abstract
    BACKGROUND: Acetylsalicylic acid (ASA) is a rat teratogen, and exposures on gestational days (GDs) 9 and 10 induce diaphragm, cardiac, and midline defects. ASA inhibits members of the cyclooxygenase (COX) family and potentially members of the carbonic anhydrase (CA) family. The objective of this study was to determine whether the mRNA developmental expression pattern for any COX or CA isoform was consistent with a model in which ASA teratogenicity is mediated through direct interaction with one of these enzymes within embryos or within the adjacent ectoplacental cone (EPC) or yolk sac. METHODS: Staged embryos, over a range (GD 9.5-12) that included ASA-sensitive and ASA-insensitive stages of organogenesis, were assayed for COX and CA mRNA levels by three techniques: microarrays; in situ hybridization quantitated by a micro-imager; and quantitative reverse transcription polymerase chain reaction. ASA- and vehicle-treated embryos also were compared to determine whether inhibition led to upregulated COX or CA mRNA expression. RESULTS: COX-2 mRNA was undetectable in embryos throughout organogenesis by any assay (although it was abundant in EPC). In contrast, COX-1 mRNA was moderately abundant in embryos throughout organogenesis. One CA isoform, CA-4, demonstrated developmentally regulated embryonic mRNA expression that coincided with ASA sensitivity ASA exposure failed to induce upregulation of any of these mRNAs. CONCLUSIONS: Although ASA may affect the embryo indirectly through interaction with COX-2 within EPC, failure to detect embryonic COX-2 mRNA argues against COX-2 functioning as a direct mediator of ASA teratogenic activity in induction of cardiac, diaphragm, and midline defects. Correlation of COX-1 and CA-4 expression with ASA sensitivity suggested that embryonic COX-1 and possibly CA4 are much more likely candidates for mediators of ASA developmental toxicity.

    Vegetal biology

  • Quilliam RS, Swarbrick PJ, Scholes JD, Rolfe SA: Imaging photosynthesis in wounded leaves of Arabidopsis thaliana J Exp Bot 57(1):55-69 April (2006)

    > Abstract | Link to journal

    • Quilliam RS, Swarbrick PJ, Scholes JD, Rolfe SA: Imaging photosynthesis in wounded leaves of Arabidopsis thaliana J Exp Bot 57(1):55-69 April (2006)

    Abstract
    Chlorophyll fluorescence imaging provides a non-invasive and non-destructive means with which to measure photosynthesis. This technique has been used, in combination with 14CO2 feeding, to study the spatial and temporal changes in source–sink relationships which occur in mechanically wounded leaves of Arabidopsis thaliana. Twenty-four hours after wounding, cells proximal to the wound margin showed a rapid induction of {Phi}II upon illumination (a measure of the efficiency of photosystem II photochemistry) whilst cells more distal to the wound margin exhibited a much slower induction of {Phi}II and a large, transient increase in NPQ (a measure of the rate constant for non-photochemical energy dissipation within the light-harvesting antenna). These results are indicative of an increase in sink strength in the vicinity of the wound and this was confirmed by the retention of 14C photosynthate in this region. It has been hypothesized that wound-induced cell wall (apoplastic) invertase (cwINV) activity plays a central role in generating localized increases in sink strength in stressed plant tissue and that hexose sugars generated by the sucrolytic activity of cwINV may act as a signal regulating gene expression. Enzyme activity measurements, quantitative RT-PCR, and T-DNA insertional mutagenesis have been used to determine that expression of AtcwINV1 is responsible for all induced cwINV activity in mechanically wounded leaves. Whilst inactivation of this gene abolished wound-induced cwINV activity, it did not affect localized alterations in source–sink relationships of wounded leaves or wound-regulated gene expression. The signals that may regulate source–sink relationships and signalling in wounded leaves are discussed. Key words: Arabidopsis thaliana, chlorophyll fluorescence imaging, invertase, photosynthesis, source–sink relationships, sugar signalling, wounding



    Books

  • Handbook of neurochemistry and molecular neurobiology Practical neurochemistry methods
    Glen B Baker, Susan Dunn, Abel Lajtha, Andrew Holt
    Springer, 2007