The Experts below are selected from a list of 507 Experts worldwide ranked by ideXlab platform

Akira Odani - One of the best experts on this subject based on the ideXlab platform.

  • Development and evaluation of a novel radioiodinated vesamicol analog as a sigma receptor imaging agent
    EJNMMI research, 2012
    Co-Authors: Kazuma Ogawa, Kazuhiro Shiba, Hiroya Kanbara, Yoji Kitamura, Takashi Kozaka, Tatsuto Kiwada, Akira Odani
    Abstract:

    Background Sigma receptors are highly expressed in human tumors and should be appropriate targets for developing tumor imaging agents. Previously, we synthesized a vesamicol analog, (+)-2-[4-(4-iodophenyl)piperidino]cyclohexanol ((+)-p IV), with a high affinity for sigma receptors and prepared radioiodinated (+)-p IV. As a result, (+)-[125I]p IV showed high tumor uptake in biodistribution experiments. However, the accumulation of radioactivity in normal tissues, such as the liver, was high. We supposed that some parts of the accumulation of (+)-p IV in the liver should be because of its high lipophilicity, and prepared and evaluated a more hydrophilic radiolabeled vesamicol analog, (+)-4-[1-(2-hydroxycyclohexyl)piperidine-4-yl]-2-Iodophenol ((+)-IV-OH).

  • Development and evaluation of a novel radioiodinated vesamicol analog as a sigma receptor imaging agent
    EJNMMI Research, 2012
    Co-Authors: Kazuma Ogawa, Kazuhiro Shiba, Hiroya Kanbara, Yoji Kitamura, Takashi Kozaka, Tatsuto Kiwada, Akira Odani
    Abstract:

    Background Sigma receptors are highly expressed in human tumors and should be appropriate targets for developing tumor imaging agents. Previously, we synthesized a vesamicol analog, (+)-2-[4-(4-iodophenyl)piperidino]cyclohexanol ((+)- p IV), with a high affinity for sigma receptors and prepared radioiodinated (+)- p IV. As a result, (+)-[^125I] p IV showed high tumor uptake in biodistribution experiments. However, the accumulation of radioactivity in normal tissues, such as the liver, was high. We supposed that some parts of the accumulation of (+)- p IV in the liver should be because of its high lipophilicity, and prepared and evaluated a more hydrophilic radiolabeled vesamicol analog, (+)-4-[1-(2-hydroxycyclohexyl)piperidine-4-yl]-2-Iodophenol ((+)-IV-OH). Methods (+)-[^125I]IV-OH was prepared by the chloramine T method from the precursor. The partition coefficient of (+)-[^125I]IV-OH was measured. Biodistribution experiments were performed by intravenous administration of a mixed solution of (+)-[^125I]IV-OH and (+)-[^131I] p IV into DU-145 tumor-bearing mice. Blocking studies were performed by intravenous injection of (+)-[^125I]IV-OH mixed with an excess amount of ligand into DU-145 tumor-bearing mice. Results The hydrophilicity of (+)-[^125I]IV-OH was much higher than that of (+)-[^125I] p IV. In biodistribution experiments, (+)-[^125I]IV-OH and (+)-[^131I] p IV showed high uptake in tumor tissues at 10-min post-injection. Although (+)-[^131I] p IV tended to be retained in most tissues, (+)-[^125I]IV-OH was cleared from most tissues. In the liver, the radioactivity level of (+)-[^125I]IV-OH was significantly lower at all time points compared to those of (+)-[^131I] p IV. In the blocking studies, co-injection of an excess amount of sigma ligands resulted in significant decreases of tumor/blood uptake ratios after injection of (+)-[^125I]IV-OH. Conclusions The results indicate that radioiodinated (+)-IV-OH holds a potential as a sigma receptor imaging agent.

Kazuma Ogawa - One of the best experts on this subject based on the ideXlab platform.

  • Development and evaluation of a novel radioiodinated vesamicol analog as a sigma receptor imaging agent
    EJNMMI research, 2012
    Co-Authors: Kazuma Ogawa, Kazuhiro Shiba, Hiroya Kanbara, Yoji Kitamura, Takashi Kozaka, Tatsuto Kiwada, Akira Odani
    Abstract:

    Background Sigma receptors are highly expressed in human tumors and should be appropriate targets for developing tumor imaging agents. Previously, we synthesized a vesamicol analog, (+)-2-[4-(4-iodophenyl)piperidino]cyclohexanol ((+)-p IV), with a high affinity for sigma receptors and prepared radioiodinated (+)-p IV. As a result, (+)-[125I]p IV showed high tumor uptake in biodistribution experiments. However, the accumulation of radioactivity in normal tissues, such as the liver, was high. We supposed that some parts of the accumulation of (+)-p IV in the liver should be because of its high lipophilicity, and prepared and evaluated a more hydrophilic radiolabeled vesamicol analog, (+)-4-[1-(2-hydroxycyclohexyl)piperidine-4-yl]-2-Iodophenol ((+)-IV-OH).

  • Development and evaluation of a novel radioiodinated vesamicol analog as a sigma receptor imaging agent
    EJNMMI Research, 2012
    Co-Authors: Kazuma Ogawa, Kazuhiro Shiba, Hiroya Kanbara, Yoji Kitamura, Takashi Kozaka, Tatsuto Kiwada, Akira Odani
    Abstract:

    Background Sigma receptors are highly expressed in human tumors and should be appropriate targets for developing tumor imaging agents. Previously, we synthesized a vesamicol analog, (+)-2-[4-(4-iodophenyl)piperidino]cyclohexanol ((+)- p IV), with a high affinity for sigma receptors and prepared radioiodinated (+)- p IV. As a result, (+)-[^125I] p IV showed high tumor uptake in biodistribution experiments. However, the accumulation of radioactivity in normal tissues, such as the liver, was high. We supposed that some parts of the accumulation of (+)- p IV in the liver should be because of its high lipophilicity, and prepared and evaluated a more hydrophilic radiolabeled vesamicol analog, (+)-4-[1-(2-hydroxycyclohexyl)piperidine-4-yl]-2-Iodophenol ((+)-IV-OH). Methods (+)-[^125I]IV-OH was prepared by the chloramine T method from the precursor. The partition coefficient of (+)-[^125I]IV-OH was measured. Biodistribution experiments were performed by intravenous administration of a mixed solution of (+)-[^125I]IV-OH and (+)-[^131I] p IV into DU-145 tumor-bearing mice. Blocking studies were performed by intravenous injection of (+)-[^125I]IV-OH mixed with an excess amount of ligand into DU-145 tumor-bearing mice. Results The hydrophilicity of (+)-[^125I]IV-OH was much higher than that of (+)-[^125I] p IV. In biodistribution experiments, (+)-[^125I]IV-OH and (+)-[^131I] p IV showed high uptake in tumor tissues at 10-min post-injection. Although (+)-[^131I] p IV tended to be retained in most tissues, (+)-[^125I]IV-OH was cleared from most tissues. In the liver, the radioactivity level of (+)-[^125I]IV-OH was significantly lower at all time points compared to those of (+)-[^131I] p IV. In the blocking studies, co-injection of an excess amount of sigma ligands resulted in significant decreases of tumor/blood uptake ratios after injection of (+)-[^125I]IV-OH. Conclusions The results indicate that radioiodinated (+)-IV-OH holds a potential as a sigma receptor imaging agent.

Frédéric Lamaty - One of the best experts on this subject based on the ideXlab platform.

Kazuhiro Shiba - One of the best experts on this subject based on the ideXlab platform.

  • Development and evaluation of a novel radioiodinated vesamicol analog as a sigma receptor imaging agent
    EJNMMI Research, 2012
    Co-Authors: Kazuma Ogawa, Kazuhiro Shiba, Hiroya Kanbara, Yoji Kitamura, Takashi Kozaka, Tatsuto Kiwada, Akira Odani
    Abstract:

    Background Sigma receptors are highly expressed in human tumors and should be appropriate targets for developing tumor imaging agents. Previously, we synthesized a vesamicol analog, (+)-2-[4-(4-iodophenyl)piperidino]cyclohexanol ((+)- p IV), with a high affinity for sigma receptors and prepared radioiodinated (+)- p IV. As a result, (+)-[^125I] p IV showed high tumor uptake in biodistribution experiments. However, the accumulation of radioactivity in normal tissues, such as the liver, was high. We supposed that some parts of the accumulation of (+)- p IV in the liver should be because of its high lipophilicity, and prepared and evaluated a more hydrophilic radiolabeled vesamicol analog, (+)-4-[1-(2-hydroxycyclohexyl)piperidine-4-yl]-2-Iodophenol ((+)-IV-OH). Methods (+)-[^125I]IV-OH was prepared by the chloramine T method from the precursor. The partition coefficient of (+)-[^125I]IV-OH was measured. Biodistribution experiments were performed by intravenous administration of a mixed solution of (+)-[^125I]IV-OH and (+)-[^131I] p IV into DU-145 tumor-bearing mice. Blocking studies were performed by intravenous injection of (+)-[^125I]IV-OH mixed with an excess amount of ligand into DU-145 tumor-bearing mice. Results The hydrophilicity of (+)-[^125I]IV-OH was much higher than that of (+)-[^125I] p IV. In biodistribution experiments, (+)-[^125I]IV-OH and (+)-[^131I] p IV showed high uptake in tumor tissues at 10-min post-injection. Although (+)-[^131I] p IV tended to be retained in most tissues, (+)-[^125I]IV-OH was cleared from most tissues. In the liver, the radioactivity level of (+)-[^125I]IV-OH was significantly lower at all time points compared to those of (+)-[^131I] p IV. In the blocking studies, co-injection of an excess amount of sigma ligands resulted in significant decreases of tumor/blood uptake ratios after injection of (+)-[^125I]IV-OH. Conclusions The results indicate that radioiodinated (+)-IV-OH holds a potential as a sigma receptor imaging agent.

  • Development and evaluation of a novel radioiodinated vesamicol analog as a sigma receptor imaging agent
    EJNMMI research, 2012
    Co-Authors: Kazuma Ogawa, Kazuhiro Shiba, Hiroya Kanbara, Yoji Kitamura, Takashi Kozaka, Tatsuto Kiwada, Akira Odani
    Abstract:

    Background Sigma receptors are highly expressed in human tumors and should be appropriate targets for developing tumor imaging agents. Previously, we synthesized a vesamicol analog, (+)-2-[4-(4-iodophenyl)piperidino]cyclohexanol ((+)-p IV), with a high affinity for sigma receptors and prepared radioiodinated (+)-p IV. As a result, (+)-[125I]p IV showed high tumor uptake in biodistribution experiments. However, the accumulation of radioactivity in normal tissues, such as the liver, was high. We supposed that some parts of the accumulation of (+)-p IV in the liver should be because of its high lipophilicity, and prepared and evaluated a more hydrophilic radiolabeled vesamicol analog, (+)-4-[1-(2-hydroxycyclohexyl)piperidine-4-yl]-2-Iodophenol ((+)-IV-OH).

  • Radioiodinated (-)-2-[4-(3-iodophenyl) piperidino] cyclohexanol: a potential radioligand for mapping presynaptic cholinergic neurons.
    Nuclear medicine communications, 1996
    Co-Authors: Kazuhiro Shiba, Hirofumi Mori, Akihiro Ichikawa, Hiroshi Matsuda, Norihisa Tonami
    Abstract:

    We synthesized the (-)-enantiomer of radioiodinated 2-[4-(3-iodophenyl)piperidino] cyclohexanol ((-)-[ 125 I]-m-iodovesamicol [(-)-[ 125 I]mIV]) and evaluated its in vivo binding specificity and affinity for the vesamicol receptor in the rat brain. Significant amounts (∼ 3% of the injected dose) of (-)-mIV accumulated and retention was prolonged. The accumulation of (-)-[ 125 I]mIV in the brain was significantly reduced by the pre- and post-administration of unlabelled vesamicol (0.5 μmol kg -1 ). Blocking and displacement studies in vivo showed that the binding affinity of (-)-[ 125 I]mIV for the vesamicol receptor was very high, but that for other receptors was very low. Autoradiographic studies showed that the regional distribution of radioactivity, as revealed by coronal sections of the rat brain, was similar for both (-)-[ 125 I]mIV and (-)-[ 3 H]vesamicol. The results demonstrated that the characteristics of (-)-l 125 I]mIV for binding sites in rat brain were similar in vivo and in vitro. Radioiodinated (-)-mIV may potentially be useful for studying presynaptic cholinergic neurons in the brain.

Yoji Kitamura - One of the best experts on this subject based on the ideXlab platform.

  • Development and evaluation of a novel radioiodinated vesamicol analog as a sigma receptor imaging agent
    EJNMMI research, 2012
    Co-Authors: Kazuma Ogawa, Kazuhiro Shiba, Hiroya Kanbara, Yoji Kitamura, Takashi Kozaka, Tatsuto Kiwada, Akira Odani
    Abstract:

    Background Sigma receptors are highly expressed in human tumors and should be appropriate targets for developing tumor imaging agents. Previously, we synthesized a vesamicol analog, (+)-2-[4-(4-iodophenyl)piperidino]cyclohexanol ((+)-p IV), with a high affinity for sigma receptors and prepared radioiodinated (+)-p IV. As a result, (+)-[125I]p IV showed high tumor uptake in biodistribution experiments. However, the accumulation of radioactivity in normal tissues, such as the liver, was high. We supposed that some parts of the accumulation of (+)-p IV in the liver should be because of its high lipophilicity, and prepared and evaluated a more hydrophilic radiolabeled vesamicol analog, (+)-4-[1-(2-hydroxycyclohexyl)piperidine-4-yl]-2-Iodophenol ((+)-IV-OH).

  • Development and evaluation of a novel radioiodinated vesamicol analog as a sigma receptor imaging agent
    EJNMMI Research, 2012
    Co-Authors: Kazuma Ogawa, Kazuhiro Shiba, Hiroya Kanbara, Yoji Kitamura, Takashi Kozaka, Tatsuto Kiwada, Akira Odani
    Abstract:

    Background Sigma receptors are highly expressed in human tumors and should be appropriate targets for developing tumor imaging agents. Previously, we synthesized a vesamicol analog, (+)-2-[4-(4-iodophenyl)piperidino]cyclohexanol ((+)- p IV), with a high affinity for sigma receptors and prepared radioiodinated (+)- p IV. As a result, (+)-[^125I] p IV showed high tumor uptake in biodistribution experiments. However, the accumulation of radioactivity in normal tissues, such as the liver, was high. We supposed that some parts of the accumulation of (+)- p IV in the liver should be because of its high lipophilicity, and prepared and evaluated a more hydrophilic radiolabeled vesamicol analog, (+)-4-[1-(2-hydroxycyclohexyl)piperidine-4-yl]-2-Iodophenol ((+)-IV-OH). Methods (+)-[^125I]IV-OH was prepared by the chloramine T method from the precursor. The partition coefficient of (+)-[^125I]IV-OH was measured. Biodistribution experiments were performed by intravenous administration of a mixed solution of (+)-[^125I]IV-OH and (+)-[^131I] p IV into DU-145 tumor-bearing mice. Blocking studies were performed by intravenous injection of (+)-[^125I]IV-OH mixed with an excess amount of ligand into DU-145 tumor-bearing mice. Results The hydrophilicity of (+)-[^125I]IV-OH was much higher than that of (+)-[^125I] p IV. In biodistribution experiments, (+)-[^125I]IV-OH and (+)-[^131I] p IV showed high uptake in tumor tissues at 10-min post-injection. Although (+)-[^131I] p IV tended to be retained in most tissues, (+)-[^125I]IV-OH was cleared from most tissues. In the liver, the radioactivity level of (+)-[^125I]IV-OH was significantly lower at all time points compared to those of (+)-[^131I] p IV. In the blocking studies, co-injection of an excess amount of sigma ligands resulted in significant decreases of tumor/blood uptake ratios after injection of (+)-[^125I]IV-OH. Conclusions The results indicate that radioiodinated (+)-IV-OH holds a potential as a sigma receptor imaging agent.