The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform
G N Woodruff - One of the best experts on this subject based on the ideXlab platform.
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Different types of bombesin receptors on neurons in the dorsal raphe nucleus and the rostral hypothalamus in rat brain slices in vitro.
Brain research, 1994Co-Authors: R D Pinnock, T Reynolds, G N WoodruffAbstract:The actions of the peptides bombesin (BN), gastrin releasing peptide (GRP), neuromedin C (NMC), Litorin and neuromedin B (NMB) were studied on neurons in slices of rat brain maintained in vitro to determine the BN receptor type present in different brain areas. Intracellular and extracellular recordings were made from hypothalamic neurons on the border of the periventricular nucleus (PVN) and suprachiasmatic nucleus (SCN) and from mesencephalic 5-HT sensitive neurons in the dorsal raphe nucleus. In the region of the brain containing the SCN and PVN, BN and the BN-related peptides excited 31 out of 77 neurons on which they were tested. There was little difference in the potency of the BN-related peptides as excitants of neurons, the EC50 being about 10 nM. The response to the peptides usually lasted between 5 and 15 min with little sign of desensitization. Using NMC, GRP and NMB as agonists, the equilibrium constant for the GRP receptor antagonist [D-Phe6]-BN-(6-13)-ethylamide was approximately 10 nM. The response to the peptides fully recovered on washout of the antagonist. The CCKB/gastrin receptor antagonist CI-988 (1 microM) had no effect on either GRP- or NMC-mediated excitation. In the dorsal nucleus 40 of 75 neurons were sensitive to the BN-related peptides. BN, [Tyr4]-BN, NMB and Litorin, were 10-20 times more potent than GRP and NMC. The responses to the BN-related peptides were not blocked by the selective GRP receptor antagonists [D-Phe6]-BN-(6-13)-methylester, [DF5Phe6][D-Ala11]-BN-(6-13)-methylester and [D-Phe6]-BN-(6-13)- ethylamide.(ABSTRACT TRUNCATED AT 250 WORDS)
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Different types of bombesin receptors on neurons in the dorsal raphe nucleus and the rostral hypothalamus in rat brain slices in vitro.
Brain Research, 1994Co-Authors: R D Pinnock, T Reynolds, G N WoodruffAbstract:The actions of the peptides bombesin (BN), gastrin releasing peptide (GRP), neuromedin C (NMC), Litorin and neuromedin B (NMB) were studied on neurons in slices of rat brain maintained in vitro to determine the BN receptor type present in different brain areas. Intracellular and extracellular recordings were made from hypothalamic neurons on the border of the periventricular nucleus (PVN) and suprachiasmatic nucleus (SCN) and from mesencephalic 5-HT sensitive neurons in the dorsal raphe nucleus. In the region of the brain containing the SCN and PVN, BN and the BN-related peptides excited 31 out of 77 neurons on which they were tested. There was little difference in the potency of the BN-related peptides as excitants of neurons, the EC50 being about 10 nM. The response to the peptides usually lasted between 5 and 15 min with little sign of desensitization. Using NMC, GRP and NMB as agonists, the equilibrium constant for the GRP receptor antagonist [d-Phe6]-BN-(6–13)-ethylamide was ∼ 10 nM. The response to the peptides fully recovered on washout of the antagonist. The CCKB/gastrin receptor antagonist CI-988 (1 μM) had no effect on either GRP- or NMC-mediated excitation. In the dorsal raphe nucleus 40 of 75 neurons were sensitive to the BN-related peptides. BN, [Tyr4]-BN, NMB and Litorin, were 10–20 times more potent than GRP and NMC. The responses to the BN-related peptides were not blocked by the selective GRP receptor antagonists [d-Phe6]-BN-(6–13)-methylester, [DF5Phe6][d-Ala11]-BN-(6–13)-methylester and [d-Phe6]-BN-(6–13)-ethylamide. These results suggest that the PVN and SCN contain a population of neurons expressing GRP receptors whilst in the dorsal raphe the majority of BN receptors expressed are of the NMB subtype.
Fatma Yurt Lambrecht - One of the best experts on this subject based on the ideXlab platform.
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in vitro evaluation of 99mtc edda tricine hynic q Litorin in gastrin releasing peptide receptor positive tumor cell lines
Journal of Drug Targeting, 2013Co-Authors: Fatma Yurt Lambrecht, Kubra Durkan, Aykut Özgür, Cumhur Gündüz, Cigir Biray Avci, Sunde Yilmaz SusluerAbstract:AbstractBombesin and its derivatives exhibit a high affinity for gastrin-releasing peptide receptor (GRPr), which is over-expressed in a variety of human cancers (prostate, pancreatic, lung, etc.). The aim of this study was to investigate the in vitro potential of the hydrazinonicotinamide (HYNIC)-Q-Litorin. 99mTc labeling was performed by using different co-ligands: tricine and ethylenediamine diacetic acid (EDDA). The radiochemical stability of radiolabeled peptide conjugates was checked at room temperature and in cysteine solution up to 24 h. The in vitro cell uptake of 99mTc-EDDA-HYNIC-Q-Litorin and 99mTc-tricine-HYNIC-Q-Litorin were evaluated on pancreatic tumor and control cell lines. Optimum specific activity and incubation time were determined for all the cell lines. The results showed that the cell uptake of the radiolabeled peptide conjugates in tumor cell lines were higher than in the control cell line. The findings of this study indicated the need for further development of in vivo study as a ...
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In vitro evaluation of 99mTc-EDDA/tricine-HYNIC-Q-Litorin in gastrin-releasing peptide receptor positive tumor cell lines
Journal of Drug Targeting, 2013Co-Authors: Fatma Yurt Lambrecht, Kubra Durkan, Aykut Özgür, Cumhur Gündüz, Cigir Biray Avci, Sunde Yilmaz SusluerAbstract:AbstractBombesin and its derivatives exhibit a high affinity for gastrin-releasing peptide receptor (GRPr), which is over-expressed in a variety of human cancers (prostate, pancreatic, lung, etc.). The aim of this study was to investigate the in vitro potential of the hydrazinonicotinamide (HYNIC)-Q-Litorin. 99mTc labeling was performed by using different co-ligands: tricine and ethylenediamine diacetic acid (EDDA). The radiochemical stability of radiolabeled peptide conjugates was checked at room temperature and in cysteine solution up to 24 h. The in vitro cell uptake of 99mTc-EDDA-HYNIC-Q-Litorin and 99mTc-tricine-HYNIC-Q-Litorin were evaluated on pancreatic tumor and control cell lines. Optimum specific activity and incubation time were determined for all the cell lines. The results showed that the cell uptake of the radiolabeled peptide conjugates in tumor cell lines were higher than in the control cell line. The findings of this study indicated the need for further development of in vivo study as a ...
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Radiolabeling of bombesin-like peptide with 99mTc: 99mTc-Litorin and biodistribution in rats.
Bioconjugate chemistry, 2007Co-Authors: Kubra Durkan, Fatma Yurt Lambrecht, Perihan ÜnakAbstract:Bombesin-like peptides are related to several human cancer receptors, including small cell lung, prostate, breast, colon, and pancreatic cancers. Litorin, an amphibian bombesin peptide derivative, is found to stimulate the contraction of smooth muscle, to stimulate gastrin, gastric acid, and pancreatic secretion, and to suppress the nutriment in in vivo experiments. In the present study, Litorin was labeled with 99mTc by the stannous chloride procedure. Labeling yield is 95 ± 1.4%, as determined by radio thin layer chromatography (RTLC) and radio high performance chromatography (RHPLC). Results of in vitro studies demonstrated a high stability in serum and cysteine solutions. In vivo biodistribution was investigated with normal male Albino Wistar rats. Biodistribution data showed fast clearance, low intestinal accumulation, and significant uptake in bombesin/gastrin releasing peptide (BN/GRP) receptor rich tissues such as the pancreas (23.56 ± 0.01 %ID/g 30 min pi). It can be blocked partially by previous...
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radiolabeling of bombesin like peptide with 99mtc 99mtc Litorin and biodistribution in rats
Bioconjugate Chemistry, 2007Co-Authors: Kubra Durkan, Fatma Yurt Lambrecht, Perihan ÜnakAbstract:Bombesin-like peptides are related to several human cancer receptors, including small cell lung, prostate, breast, colon, and pancreatic cancers. Litorin, an amphibian bombesin peptide derivative, is found to stimulate the contraction of smooth muscle, to stimulate gastrin, gastric acid, and pancreatic secretion, and to suppress the nutriment in in vivo experiments. In the present study, Litorin was labeled with 99m Tc by the stannous chloride procedure. Labeling yield is 95 ± 1.4%, as determined by radio thin layer chromatography (RTLC) and radio high performance chromatography (RHPLC). Results of in vitro studies demonstrated a high stability in serum and cysteine solutions. In vivo biodistribution was investigated with normal male Albino Wistar rats. Biodistribution data showed fast clearance, low intestinal accumulation, and significant uptake in bombesin/gastrin releasing peptide (BN/GRP) receptor rich tissues such as the pancreas (23.56 ± 0.01 %ID/g 30 min pi). It can be blocked partially by previous administration of 'cold' Litorin. The results showed specificity of the uptake. As 99m Tc-Litorin displays good radiolabeling and biodistribution, it is a potentially useful radiopharmaceutical for detection of bombesin receptor-expressing cancers.
Sunde Yilmaz Susluer - One of the best experts on this subject based on the ideXlab platform.
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in vitro evaluation of 99mtc edda tricine hynic q Litorin in gastrin releasing peptide receptor positive tumor cell lines
Journal of Drug Targeting, 2013Co-Authors: Fatma Yurt Lambrecht, Kubra Durkan, Aykut Özgür, Cumhur Gündüz, Cigir Biray Avci, Sunde Yilmaz SusluerAbstract:AbstractBombesin and its derivatives exhibit a high affinity for gastrin-releasing peptide receptor (GRPr), which is over-expressed in a variety of human cancers (prostate, pancreatic, lung, etc.). The aim of this study was to investigate the in vitro potential of the hydrazinonicotinamide (HYNIC)-Q-Litorin. 99mTc labeling was performed by using different co-ligands: tricine and ethylenediamine diacetic acid (EDDA). The radiochemical stability of radiolabeled peptide conjugates was checked at room temperature and in cysteine solution up to 24 h. The in vitro cell uptake of 99mTc-EDDA-HYNIC-Q-Litorin and 99mTc-tricine-HYNIC-Q-Litorin were evaluated on pancreatic tumor and control cell lines. Optimum specific activity and incubation time were determined for all the cell lines. The results showed that the cell uptake of the radiolabeled peptide conjugates in tumor cell lines were higher than in the control cell line. The findings of this study indicated the need for further development of in vivo study as a ...
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In vitro evaluation of 99mTc-EDDA/tricine-HYNIC-Q-Litorin in gastrin-releasing peptide receptor positive tumor cell lines
Journal of Drug Targeting, 2013Co-Authors: Fatma Yurt Lambrecht, Kubra Durkan, Aykut Özgür, Cumhur Gündüz, Cigir Biray Avci, Sunde Yilmaz SusluerAbstract:AbstractBombesin and its derivatives exhibit a high affinity for gastrin-releasing peptide receptor (GRPr), which is over-expressed in a variety of human cancers (prostate, pancreatic, lung, etc.). The aim of this study was to investigate the in vitro potential of the hydrazinonicotinamide (HYNIC)-Q-Litorin. 99mTc labeling was performed by using different co-ligands: tricine and ethylenediamine diacetic acid (EDDA). The radiochemical stability of radiolabeled peptide conjugates was checked at room temperature and in cysteine solution up to 24 h. The in vitro cell uptake of 99mTc-EDDA-HYNIC-Q-Litorin and 99mTc-tricine-HYNIC-Q-Litorin were evaluated on pancreatic tumor and control cell lines. Optimum specific activity and incubation time were determined for all the cell lines. The results showed that the cell uptake of the radiolabeled peptide conjugates in tumor cell lines were higher than in the control cell line. The findings of this study indicated the need for further development of in vivo study as a ...
Kubra Durkan - One of the best experts on this subject based on the ideXlab platform.
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in vitro evaluation of 99mtc edda tricine hynic q Litorin in gastrin releasing peptide receptor positive tumor cell lines
Journal of Drug Targeting, 2013Co-Authors: Fatma Yurt Lambrecht, Kubra Durkan, Aykut Özgür, Cumhur Gündüz, Cigir Biray Avci, Sunde Yilmaz SusluerAbstract:AbstractBombesin and its derivatives exhibit a high affinity for gastrin-releasing peptide receptor (GRPr), which is over-expressed in a variety of human cancers (prostate, pancreatic, lung, etc.). The aim of this study was to investigate the in vitro potential of the hydrazinonicotinamide (HYNIC)-Q-Litorin. 99mTc labeling was performed by using different co-ligands: tricine and ethylenediamine diacetic acid (EDDA). The radiochemical stability of radiolabeled peptide conjugates was checked at room temperature and in cysteine solution up to 24 h. The in vitro cell uptake of 99mTc-EDDA-HYNIC-Q-Litorin and 99mTc-tricine-HYNIC-Q-Litorin were evaluated on pancreatic tumor and control cell lines. Optimum specific activity and incubation time were determined for all the cell lines. The results showed that the cell uptake of the radiolabeled peptide conjugates in tumor cell lines were higher than in the control cell line. The findings of this study indicated the need for further development of in vivo study as a ...
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In vitro evaluation of 99mTc-EDDA/tricine-HYNIC-Q-Litorin in gastrin-releasing peptide receptor positive tumor cell lines
Journal of Drug Targeting, 2013Co-Authors: Fatma Yurt Lambrecht, Kubra Durkan, Aykut Özgür, Cumhur Gündüz, Cigir Biray Avci, Sunde Yilmaz SusluerAbstract:AbstractBombesin and its derivatives exhibit a high affinity for gastrin-releasing peptide receptor (GRPr), which is over-expressed in a variety of human cancers (prostate, pancreatic, lung, etc.). The aim of this study was to investigate the in vitro potential of the hydrazinonicotinamide (HYNIC)-Q-Litorin. 99mTc labeling was performed by using different co-ligands: tricine and ethylenediamine diacetic acid (EDDA). The radiochemical stability of radiolabeled peptide conjugates was checked at room temperature and in cysteine solution up to 24 h. The in vitro cell uptake of 99mTc-EDDA-HYNIC-Q-Litorin and 99mTc-tricine-HYNIC-Q-Litorin were evaluated on pancreatic tumor and control cell lines. Optimum specific activity and incubation time were determined for all the cell lines. The results showed that the cell uptake of the radiolabeled peptide conjugates in tumor cell lines were higher than in the control cell line. The findings of this study indicated the need for further development of in vivo study as a ...
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Radiolabeling of bombesin-like peptide with 99mTc: 99mTc-Litorin and biodistribution in rats.
Bioconjugate chemistry, 2007Co-Authors: Kubra Durkan, Fatma Yurt Lambrecht, Perihan ÜnakAbstract:Bombesin-like peptides are related to several human cancer receptors, including small cell lung, prostate, breast, colon, and pancreatic cancers. Litorin, an amphibian bombesin peptide derivative, is found to stimulate the contraction of smooth muscle, to stimulate gastrin, gastric acid, and pancreatic secretion, and to suppress the nutriment in in vivo experiments. In the present study, Litorin was labeled with 99mTc by the stannous chloride procedure. Labeling yield is 95 ± 1.4%, as determined by radio thin layer chromatography (RTLC) and radio high performance chromatography (RHPLC). Results of in vitro studies demonstrated a high stability in serum and cysteine solutions. In vivo biodistribution was investigated with normal male Albino Wistar rats. Biodistribution data showed fast clearance, low intestinal accumulation, and significant uptake in bombesin/gastrin releasing peptide (BN/GRP) receptor rich tissues such as the pancreas (23.56 ± 0.01 %ID/g 30 min pi). It can be blocked partially by previous...
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radiolabeling of bombesin like peptide with 99mtc 99mtc Litorin and biodistribution in rats
Bioconjugate Chemistry, 2007Co-Authors: Kubra Durkan, Fatma Yurt Lambrecht, Perihan ÜnakAbstract:Bombesin-like peptides are related to several human cancer receptors, including small cell lung, prostate, breast, colon, and pancreatic cancers. Litorin, an amphibian bombesin peptide derivative, is found to stimulate the contraction of smooth muscle, to stimulate gastrin, gastric acid, and pancreatic secretion, and to suppress the nutriment in in vivo experiments. In the present study, Litorin was labeled with 99m Tc by the stannous chloride procedure. Labeling yield is 95 ± 1.4%, as determined by radio thin layer chromatography (RTLC) and radio high performance chromatography (RHPLC). Results of in vitro studies demonstrated a high stability in serum and cysteine solutions. In vivo biodistribution was investigated with normal male Albino Wistar rats. Biodistribution data showed fast clearance, low intestinal accumulation, and significant uptake in bombesin/gastrin releasing peptide (BN/GRP) receptor rich tissues such as the pancreas (23.56 ± 0.01 %ID/g 30 min pi). It can be blocked partially by previous administration of 'cold' Litorin. The results showed specificity of the uptake. As 99m Tc-Litorin displays good radiolabeling and biodistribution, it is a potentially useful radiopharmaceutical for detection of bombesin receptor-expressing cancers.
R D Pinnock - One of the best experts on this subject based on the ideXlab platform.
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Different types of bombesin receptors on neurons in the dorsal raphe nucleus and the rostral hypothalamus in rat brain slices in vitro.
Brain research, 1994Co-Authors: R D Pinnock, T Reynolds, G N WoodruffAbstract:The actions of the peptides bombesin (BN), gastrin releasing peptide (GRP), neuromedin C (NMC), Litorin and neuromedin B (NMB) were studied on neurons in slices of rat brain maintained in vitro to determine the BN receptor type present in different brain areas. Intracellular and extracellular recordings were made from hypothalamic neurons on the border of the periventricular nucleus (PVN) and suprachiasmatic nucleus (SCN) and from mesencephalic 5-HT sensitive neurons in the dorsal raphe nucleus. In the region of the brain containing the SCN and PVN, BN and the BN-related peptides excited 31 out of 77 neurons on which they were tested. There was little difference in the potency of the BN-related peptides as excitants of neurons, the EC50 being about 10 nM. The response to the peptides usually lasted between 5 and 15 min with little sign of desensitization. Using NMC, GRP and NMB as agonists, the equilibrium constant for the GRP receptor antagonist [D-Phe6]-BN-(6-13)-ethylamide was approximately 10 nM. The response to the peptides fully recovered on washout of the antagonist. The CCKB/gastrin receptor antagonist CI-988 (1 microM) had no effect on either GRP- or NMC-mediated excitation. In the dorsal nucleus 40 of 75 neurons were sensitive to the BN-related peptides. BN, [Tyr4]-BN, NMB and Litorin, were 10-20 times more potent than GRP and NMC. The responses to the BN-related peptides were not blocked by the selective GRP receptor antagonists [D-Phe6]-BN-(6-13)-methylester, [DF5Phe6][D-Ala11]-BN-(6-13)-methylester and [D-Phe6]-BN-(6-13)- ethylamide.(ABSTRACT TRUNCATED AT 250 WORDS)
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Different types of bombesin receptors on neurons in the dorsal raphe nucleus and the rostral hypothalamus in rat brain slices in vitro.
Brain Research, 1994Co-Authors: R D Pinnock, T Reynolds, G N WoodruffAbstract:The actions of the peptides bombesin (BN), gastrin releasing peptide (GRP), neuromedin C (NMC), Litorin and neuromedin B (NMB) were studied on neurons in slices of rat brain maintained in vitro to determine the BN receptor type present in different brain areas. Intracellular and extracellular recordings were made from hypothalamic neurons on the border of the periventricular nucleus (PVN) and suprachiasmatic nucleus (SCN) and from mesencephalic 5-HT sensitive neurons in the dorsal raphe nucleus. In the region of the brain containing the SCN and PVN, BN and the BN-related peptides excited 31 out of 77 neurons on which they were tested. There was little difference in the potency of the BN-related peptides as excitants of neurons, the EC50 being about 10 nM. The response to the peptides usually lasted between 5 and 15 min with little sign of desensitization. Using NMC, GRP and NMB as agonists, the equilibrium constant for the GRP receptor antagonist [d-Phe6]-BN-(6–13)-ethylamide was ∼ 10 nM. The response to the peptides fully recovered on washout of the antagonist. The CCKB/gastrin receptor antagonist CI-988 (1 μM) had no effect on either GRP- or NMC-mediated excitation. In the dorsal raphe nucleus 40 of 75 neurons were sensitive to the BN-related peptides. BN, [Tyr4]-BN, NMB and Litorin, were 10–20 times more potent than GRP and NMC. The responses to the BN-related peptides were not blocked by the selective GRP receptor antagonists [d-Phe6]-BN-(6–13)-methylester, [DF5Phe6][d-Ala11]-BN-(6–13)-methylester and [d-Phe6]-BN-(6–13)-ethylamide. These results suggest that the PVN and SCN contain a population of neurons expressing GRP receptors whilst in the dorsal raphe the majority of BN receptors expressed are of the NMB subtype.