John Lister-James - Academia.edu (original) (raw)

Papers by John Lister-James

Journal of Thoracic Oncology, 2009

Both small cell and non-small cell lung cancer overexpress somatostatin receptors (SSTR). P2045 p... more Both small cell and non-small cell lung cancer overexpress somatostatin receptors (SSTR). P2045 peptide is an 11-amino acid somatostatin analog that binds with high affinity to SSTR and can be labeled with Tc-99m to gauge receptor prevalence or with Re-188 for 2.1 MeV beta radiotherapy. To evaluate the safety of this approach, a phase I dose-escalation study of Re-188 P2045 in SSTR-positive lung cancer was performed. Patients were required to have stage IIIb or IV or recurrent non-small cell lung cancer or extensive stage or recurrent small cell lung cancer, performance status 0 to 1, and normal organ function. There were no limitations on the number of prior therapies. Tumor SSTR was detected with Tc-99m P2045. If positive and projected renal dose of radiation from Re-188 P2045 was less than 20 Gy, treatment with escalating doses of Re-188 P2045 was instituted. Three doses were evaluated 30 mCi/m2, 60 mCi/m2, and 90 mCi/m2. A single dose of Re-188 P2045 was allowed. Dose-limiting toxicity was defined as > or = grade 3 nonhematologic toxicity or grade 4 hematologic toxicity. Fifteen patients were enrolled. The median age was 61 years. Fourteen patients had > or = 2 prior chemotherapy regimens. All were imaged with Tc-99m P2045, eight patients received Re-188 P2045. The most common toxicity was mild lymphopenia. The trial was halted at the 90 mCi/m2 level when three patients were projected to have renal radiation doses above 20 Gy. The monoclonal antibody was not determined, and no responses were seen. Five of the eight patients (62.5%, 95% CI: 24-91%) had stable disease for at least 8 weeks, all of whom entered the study with progressive disease. Median overall survival was 11.5 months. This trial demonstrated that Re-188 P2045 was well tolerated. Tc-99m P2045 imaging allows identification of patients who may benefit from this treatment. Although responses were not seen, survival for these heavily pretreated patients is interesting and merits further research.

Journal of The Chemical Society-perkin Transactions 1, 1982

ABSTRACT 3β-Acetoxy-5α,6β-dichloropregn-16-en-20-one (1), on treatment with elemental fluorine at... more ABSTRACT 3β-Acetoxy-5α,6β-dichloropregn-16-en-20-one (1), on treatment with elemental fluorine at low temperature, gave the 16α,17α-difluoro-adduct (2) and, by rearrangement, the 13α,16α-difluoro-17β-methyl derivative (3). The adduct (2) was subsequently converted via a short, efficient synthetic sequence into 16α,17α-difluoroprogesterone (5). In contrast, fluorination of 21-acetoxypregna-1,4,16-triene-3,11,20-trione (6) afforded the corresponding 16α,17α-difluoro-adduct (8) in low yield. Similarly, androsta-1,4,6-triene-3,17-dione (9) was converted into the 6α,7α-difluoro-adduct (11). Fluorination with CF3OF led to an increased yield of the adduct (11) and also afforded the 6α-trifluoromethoxy-7α-fluoro-adduct (12). Dehydrofluorination of the latter gave 6-trifluoromethoxyandrosta-1,4,6-triene-3,17-dione (13). 21-Acetoxy-11β,17α-dihydroxypregna-1,4,6-triene-3,20-dione (5) was prepared by stepwise dehydrogenation of cortisol acetate (14). Subsequent low temperature treatment with CF3OF resulted in two major products, formulated as the adducts (17) and (18).

Journal of The Chemical Society-perkin Transactions 1, 1982

ABSTRACT Treatment of the N-methylnitrone (1b) of dichlorisone acetate (E–Z-mixture) with toluene... more ABSTRACT Treatment of the N-methylnitrone (1b) of dichlorisone acetate (E–Z-mixture) with toluene-p-sulphonyl chloride in pyridine in the presence of water gave dichlorisone acetate (1a)(88%). In the presence of hydrogen sulphide, however, the nitrone was deoxygenated to give the corresponding imine (1c), which on prolonged reaction with hydrogen sulphide in pyridine afforded the corresponding 1,4-diene-3-thione (1d). Similarly prepared were the unstable imines (2d), (3c), and (4c), which were smoothly converted into the corresponding thiones (2e), (3d), and (4d), respectively. In the absence of strong nucleophiles, dichlorisone acetate nitrone (1b) was treated with toluene-p-sulphonyl chloride in pyridine to give the corresponding trienimine (1g)(45%). Under similar conditions, however, prednisolone-21-propionate nitrone (3b) gave the 2-p-tolylsulphonyloxy-derivative (3e) as the major product. Separate treatment of both Z- and E-isomers of dehydrotestosterone acetate nitrone [(2b) and (2c)] afforded, in both cases, the 2-p-tolylsulphonyloxy-derivative (2g)(25%), whereas betamethasone nitrone (4b) gave a mixture of the 2-p-tolylsulphonyloxy-dienimine (4f) and the trienimine (4h) in low yield.

Nuclear Medicine and Biology, 2007

We report here the results of studies on the in vitro receptor binding affinity, in vivo tumor up... more We report here the results of studies on the in vitro receptor binding affinity, in vivo tumor uptake and biodistribution of two ""re labeled peptides. Methods: Peptides P587 and P829 were synthe sized by N-a-Fmoc peptide chemistry, purified by reversed-phase HPLC and characterized by fast-atom bombardment mass spectrometry. The peptides were labeled with 99mTcby ligand exchange from 99mTc-glucoheptonate. In vitro somatostatin receptors (SSTR)binding affinities of P587, P829 and their oxorhenium complexes, [DTPAJoctreotide and ln-[DTPA]octreotide were determined in an inhibition assay using AR42J rat pancreatic tumor cell membranes and 125l-[Tyr3]somatostatin-14 as the probe. In vivo single-and dual-tracer studies of ""Tc peptides and 111ln-[DTPA]octreotide were carried out using Lewis rats bearing CA20948 rat pancreatic tumor implants. Results: Technetium-99m-P587 and 99rrTc-P829 of high-specific activity (>60 Ci (2.2 TBq)/mmole) were prepared in >90% radiochemical yield. P587 and P829 had a Ki = 2.5 n/Wand 10 n/W, respectively.

The diagnosis of recurrent deep vein thrombosis (DVT) is challenging. Imaging with radiolabeled p... more The diagnosis of recurrent deep vein thrombosis (DVT) is challenging. Imaging with radiolabeled peptides offers a new approach for detecting acute DVT. Technetium Tc 99m ((99m)Tc)-apcitide binds with high affinity and specificity to the glycoprotein IIb/IIIa receptors expressed on activated platelets and, therefore, (99m)Tc-apcitide scintigraphy should be negative with residual abnormalities caused by old, inactive thrombi and positive with new, active thrombi. In a prospective multicenter study, (99m)Tc-apcitide imaging was performed on 38 patients with a newly diagnosed first DVT (group 1) and 40 patients with previous DVT, symptoms of postthrombotic syndrome, and chronic intraluminal abnormalities on ultrasonography (group 2). Images were interpreted in a blinded fashion by 2 experts and by newly trained nuclear medicine physicians. The sensitivity and specificity of (99m)Tc-apcitide were determined by calculating the proportion of scans in group 1 patients that were read as "positive for acute DVT" and the proportion of scans in group 2 patients that were read as "negative for acute DVT," respectively. When read by 2 experts, ( 99m)Tc-apcitide had a sensitivity of 92% for both readers and specificities of 82% and 90%. Agreement between the experts was excellent. However, the accuracy and interreader agreement for newly trained nuclear medicine physicians were lower. Technetium Tc 99m-apcitide scintigraphy has potential utility in suspected recurrent DVT because it detects most acute thrombi and has few false-positive results in patients with previous DVT. However, the accuracy appears to depend on the training and experience of the interpreters.

Journal of Medicinal Chemistry, 1996

Platelet-specific compounds which are radiolabeled with gamma-emitting radionuclides may be parti... more Platelet-specific compounds which are radiolabeled with gamma-emitting radionuclides may be particularly useful for the noninvasive in vivo detection of thrombi. The synthesis of peptides which are potent inhibitors of platelet aggregation and which contain a chelator for the radionuclide technetium-99m are described. The target compounds were designed such that stable, oxotechnetium(V) species could be prepared where the site of metal coordination was well defined. A strategy was employed where the pharmacophore-Arg-Gly-Asp-(RGD), or RGD mimetic, was constrained in a ring which was formed by the S-alkylation of a cysteine residue with an N-terminal chloroacetyl group. Binding affinities were enhanced by the replacement of arginine with the arginine mimetics S-(3-aminopropyl)cysteine and 4-amidinophenylalanine. Further enhancements could be obtained by the synthesis of oligomers which contained two or more rings containing receptor binding regions. The increase in binding affinity seen was more than that expected from a simple stoichiometric increase of pharmacophore. The most potent compounds described had IC50s of approximately 0.03 microM for the inhibition of human platelet aggregation. Two of the more potent peptides (P280 and P748) were labeled with technetium-99m and assessed in a canine thrombosis model. The 99m Tc complexes of the peptides prepared in this work hold promise as thrombus imaging agents due to their high receptor binding affinity, ease of preparation, and expected rapid pharmacokinetics.

Journal of Medicinal Chemistry, 1996

The synthesis of peptides which possess a high affinity for the somatostatin receptor and contain... more The synthesis of peptides which possess a high affinity for the somatostatin receptor and contain a chelator for the radionuclide technetium-99m is described. The target compounds were designed such that they would form stable, oxotechnetium(V) chelate complexes in which the Oxorhenium(V) chelate complexes of these peptides were prepared as nonradioactive surrogates for the technetium complexes. Peptide oxorhenium complexes and Tc-99m complexes eluted closely upon HPLC analysis. The receptor-binding affinities of both the free and rhenium-coordinated species were measured in vitro. The binding affinities of the free peptides (Ki's in the 0.25 - 10 nM range) compared favorably with [DTPA]octreotide (Ki = 1.6 nM), which, as the indium-111 complex, is already approved for somatostatin receptor (SSTR)-expressing tumor imaging in the United States and Europe. Furthermore, the rhenium-coordinated peptides had binding affinities which, in many cases, were higher than those of the corresponding free peptides, with several complexes having a Ki's of 0.1 nM. Some of the more potent SSTR-binding peptides were labeled with technetium-99m and assessed in an in vivo study with tumor-bearing rats. The 99m Tc-labeled peptides prepared in this study should be useful as SSTR-expressing tumor-imaging agents due to their high SSTR-binding affinities, ease of preparation, and, because they are low molecular weight peptides, expected pharmacokinetics characterized by rapid tracer excretion from the body resulting in high-contrast images.

American Journal of Therapeutics, 1995

We have previously shown that after administration of (123)I-SP-4 (a synthetic ApoB peptide fragm... more We have previously shown that after administration of (123)I-SP-4 (a synthetic ApoB peptide fragment) to Watanabe heritable hyperlipidemic (WHHL) rabbits that foci of tracer uptake can be identified by external gamma camera imaging which correspond to regions of the aortas found to contain abundant atherosclerotic lesions at postmortem evaluation. Because (99m)Tc is preferred over (123)I for scintigraphic imaging, we prepared a (99m)Tc-labeled form of the SP-4 peptide, designated (99m)Tc-P199. To assess the feasibility of detecting atherosclerotic lesions using (99m)Tc-P199 and to compare the relative uptake of the (99m)Tc-labeled and radioiodinated peptides by such lesions, an admixture of (99m)Tc-199 and (125)I-SP-4 was administered to 11 WHHL and 2 normal rabbits. These animals were imaged for up to 3 h and were sacrificed 3--4 h after injection. The extent of aortic lesion involvement and radiotracer uptake were quantitatively compared by planimetric analysis of photographs of the endothelial surface, (99m)Tc-P199 ex vivo images and (125)I-SP-4 autoradiograms of the excised aortas. Pairwise correlation coefficients for planimetric analysis were as follows: photographs versus ex vivo images, r = 0.83, p = 0.003; photographs versus autoradiograms, r = 0.87, p = 0.001; ex vivo images versus autoradiograms, r = 0.83, p = 0.003. (99m)Tc-199 in vivo gamma camera images revealed relatively weak focal aortic uptake in 8 of 11 WHHL rabbits manifesting aortic lesions, and focal carotid artery uptake in 4 of 6 WHHL rabbits manifesting carotid lesions. Neither aortic nor carotid foci were visualized in the normal rabbits. We conclude that (99m)Tc-199 localizes specifically in atherosclerotic lesions and may be useful for external imaging of atherosclerosis.

Journal of Medicinal Chemistry, 2007

Somatostatin derivative peptides previously designed for radiodiagnostic purposes (99mTc P829 or ... more Somatostatin derivative peptides previously designed for radiodiagnostic purposes (99mTc P829 or 99mTc depreotide) were reoptimized for radiotherapy of tumors with rhenium radioisotopes. An optimized pharmacophore peptide P1839 was derived by in vitro binding affinity assay to AR42J rat pancreatic tumor cell membranes. Peptides with chelating domains and their oxorhenium(V) complexes were tested in vitro for binding to NCI H69 human SCLC tumor membranes. Further optimization entailed radiolabeling with 99mTc and biodistribution in an AR42J xenograft mouse model. Kidney uptake was decreased substantially by removing positively charged residues. Neutral N3S diamide amine thiol chelators with no adjacent positive charges had the best overall properties. Substituting an aromatic amino acid into the chelator approximately doubled the tumor uptake. The final optimized peptide P2045 (39) radiolabeled with 99mTc exhibited increased tumor uptake ( approximately 25 %ID/g at 1.5 h), lower kidney uptake ( approximately 4.8 %ID/g at 1.5 h), and extensive urinary excretion (59 %ID at 1.5 h). Finally, comparison biodistribution studies between 99mTc and 188Re (39) showed a good correlation between the two metal complexes and demonstrated prolonged tumor retention (> or =24 h).

The objective of this work was the preclinical evaluation of ""Tc-P280, a """Tc-labeled peptide h... more The objective of this work was the preclinical evaluation of ""Tc-P280, a """Tc-labeled peptide having high affinity and specificity for the GPIIb/llla receptor expressed on activated platelets, for use as a thrombus imaging agent. Methods: The affinity and specificity of P280 peptide for the GPIIb/llla receptor was assessed by the inhibition of ADP-stimulated human platelet aggregation, the inhibi tion of the binding of fibrinogen to the GPIIb/llla receptor and the inhibition of the binding of vitronectin to the vitronectin receptor. P280 peptide was radiolabeled with 99mTcby ligand exchange using 99mTc-glucoheptonate. The ability of 99mTc-P280 to detect thrombi in vivo was assessed using a canine venous thrombosis model and the biodistribution of 99mTc-P280 was determined in rats and rabbits. Results: P280 peptide had an IC50 of 79 nM for the inhibition of aggregation of human platelets in platelet rich plasma, an ICgo of 6.8 nM for the inhibition of fibrinogen binding to the GPIIb/llla receptor and an ICso of 13 /nM for the inhibition of vitronectin binding to the vitronectin receptor, showing the high in vitro receptor binding affinity and specificity of the peptide. 99mTc-P280 was readily prepared in >90% radiochemical yield and purity and provided images of femoral vein thrombi in the canine model by 1 hr postinjection (thrombus-to-blood ratio of 4.4 and thrombus-tomuscle ratio of 11 at 4 hr). Dog, rat and rabbit studies all showed rapid clearance of the radiotracer from the blood and rapid renal excretion. Conclusion: The combination of high in vitro receptorbinding affinity and specificity, in vivo thrombus imaging and fast clearance support the evaluation of 99mTc-P280 as a clinical imag ing agent.

surface provides the basis for the successful clinical use of radiolabeled ligands for the in viv... more surface provides the basis for the successful clinical use of radiolabeled ligands for the in vivo localization of tumor sites. We have characterized the in vitro binding properties of the novel SSTR ligand "mTc-P829 using primary human tumors (carcinoids, breast cancers, intestinal adenocarcinomas, pheochromocytomas, small cell and non-small cell lung cancer, and melanomas; n = 28), various tumor cell lines, and COS7 cells transfected with the human SSTR (hSSTR) subtypes 1, 2, 3, 4, and 5. """Tc-P829 bound to primary tumor cells and tumor cell lines with high affinity and high capacity. The dissociation constants (A,,I ranged between 1 and 20 IIM. '"""Tc-1'829 also bound with high affinity to the transfected hSSTR2 (Ka, 2.5 nM), hSSTRS (Ad, 2 nM), and hSSTR3 (K¿,1.5 nM). Binding of "'""Tt-PH29 to hSSTR3 was found to be displaceable by unla-

Journal of The American College of Cardiology, 1995

has considerable potential as a clinical imaging agent for the detection of venous thromboembolism.

Nuclear Medicine Communications, 2000

Bioconjugate Chemistry, 1990

Bifunctional chelators for labeling antibodies with 99mTc based on the N3S core of (mercaptoacety... more Bifunctional chelators for labeling antibodies with 99mTc based on the N3S core of (mercaptoacetyl)-triglycine having ester or amide linking moieties were synthesized and site-specifically attached to the sulfhydryl groups of the Fab' fragment of antimyosin. Protein labeling was quantitative after 15 min; postlabeling purification was not necessary. The radiolabeled conjugates exhibited no loss of immunoreactivity. Under basic conditions, the ester-linked conjugate lost 95% of the radiolabel in the form of the 99mTc complex of (mercaptoacetyl)triglycine as determined by RP-HPLC, while the radioactivity in the amide-linked conjugate remained completely bound to the protein. In a mouse biodistribution study, the ester-linked conjugate showed a 2-fold enhancement in clearance from the kidney when compared to the amide-linked product.

We report here the results of studies on the in vitro receptor binding affinity, in vivo tumor up... more We report here the results of studies on the in vitro receptor binding affinity, in vivo tumor uptake and biodistribution of two ""re labeled peptides. Methods: Peptides P587 and P829 were synthe sized by N-a-Fmoc peptide chemistry, purified by reversed-phase HPLC and characterized by fast-atom bombardment mass spectrometry. The peptides were labeled with 99mTcby ligand exchange from 99mTc-glucoheptonate. In vitro somatostatin receptors (SSTR)binding affinities of P587, P829 and their oxorhenium complexes, [DTPAJoctreotide and ln-[DTPA]octreotide were determined in an inhibition assay using AR42J rat pancreatic tumor cell membranes and 125l-[Tyr3]somatostatin-14 as the probe. In vivo single-and dual-tracer studies of ""Tc peptides and 111ln-[DTPA]octreotide were carried out using Lewis rats bearing CA20948 rat pancreatic tumor implants. Results: Technetium-99m-P587 and 99rrTc-P829 of high-specific activity (>60 Ci (2.2 TBq)/mmole) were prepared in >90% radiochemical yield. P587 and P829 had a Ki = 2.5 n/Wand 10 n/W, respectively.

American Journal of Therapeutics, 1996

I-125 labeled SP4 is a synthetic oligopeptide derived from apolipoprotein B of low-density lipopr... more I-125 labeled SP4 is a synthetic oligopeptide derived from apolipoprotein B of low-density lipoprotein that has been shown to localized in atherosclerotic plaques in experimental animals. However, its biodistribution and mechanism of localization need to be further elucidated. Twenty-four cholesterol-fed (CF) and 20 normal (NL) New Zealand White rabbits were injected with I-125-SP4 and killed 15 to 30 min (6 NL; 6 CF) or 2 h (14 NL; 18 CF) later. We obtained aortic autoradiograms and activity concentrations (% injected dose/gm) in aortic segments and other tissues. The uptake of I-125-SP4 was higher in CF than in NL rabbits in all aortic segments (p < 0.05). I-125-SP4 was cleared rapidly in both CF and NL rabbits with 60 to 70% of the injected dose cleared from the blood by 1 h. No statistically significant differences in radiotracer biodistribution were observed between NL and CF rabbits although activity tended to be higher in the liver, gallbladder, and intestine in NL rabbits and in the kidney and spleen in CF rabbits. Silver grains were distributed mainly on foam cells of the fatty streaks in aortic microautoradiograms from two additional rabbits that had been injected with I-125-SP4. There were 23,518 plus minus 15,878 (SD) grains/mm(2) in fatty plaques but only 14,669 plus minus 11,035 grains/mm(2) in media muscle (p < 0.0001 [9 sections, 17 areas evaluated] in an atherosclerotic animal) in injected animals and 13,439 plus minus 5,565 grains/mm(2) in media muscle (two sections, four areas) in the normal control animals (NS versus media of atherosclerotic animal). I-125-SP4 specifically localizes in aortic atherosclerotic plaques in CF rabbits. There is no significant difference in tissue distribution between normal and CF rabbits except in the aorta. Preliminarily, it appears that the site of tracer uptake is on foam cells and this suggests the possibility of relative specificity for fatty plaque.

European Journal of Nuclear Medicine, 1986

Technetium-99m hexakis (t-butylisonitrile) technetium (I) (99mTc-TBI) is a new myocardial perfusi... more Technetium-99m hexakis (t-butylisonitrile) technetium (I) (99mTc-TBI) is a new myocardial perfusion imaging agent. To determine its potential in the evaluation of myocardial infarction, 15 patients with suspected or confirmed acute infarction were studied by bedside imaging in the coronary care unit. Good-quality planar scintigrams in multiple projections were obtained in 13 patients. Gated perfusion studies were performed in 14 patients, and for comparison 13 of these were restudied 24–72 h later by standard gated equilibrium blood pool radionuclide ventriculography. Conventional and planar scintigraphic criteria for myocardial infarction (acute or old) agreed in 12 (92%) patients (k=0.81, pk=0.49, p99mTc-TBI scintigraphy were in complete agreement for 25 (64%) of 39 left ventricular segments (k=0.35, p99mTc-TBI scintigraphy. Therefore, 99mTc-TBI scintigraphy can readily provide data on regional myocardial perfusion and wall motion, permitting detection and localization of areas of myocardial infarction. The superior imaging properties, ready availability and low cost of 99mTc point to the considerable potential value of 99mTc-TBI in assessing patients with suspected or confirmed myocardial infarction.

Inorganic Chemistry, 1988

The coordination chemistry of amide and thiolate ligands has a strong basis in both biology and c... more The coordination chemistry of amide and thiolate ligands has a strong basis in both biology and chemistry, and reviews have been dedicated to the field. 2 We are particularly interested in this area of chemistry as it pertains to the preparation of new classes of chelate ...

Journal of Thoracic Oncology, 2009

Both small cell and non-small cell lung cancer overexpress somatostatin receptors (SSTR). P2045 p... more Both small cell and non-small cell lung cancer overexpress somatostatin receptors (SSTR). P2045 peptide is an 11-amino acid somatostatin analog that binds with high affinity to SSTR and can be labeled with Tc-99m to gauge receptor prevalence or with Re-188 for 2.1 MeV beta radiotherapy. To evaluate the safety of this approach, a phase I dose-escalation study of Re-188 P2045 in SSTR-positive lung cancer was performed. Patients were required to have stage IIIb or IV or recurrent non-small cell lung cancer or extensive stage or recurrent small cell lung cancer, performance status 0 to 1, and normal organ function. There were no limitations on the number of prior therapies. Tumor SSTR was detected with Tc-99m P2045. If positive and projected renal dose of radiation from Re-188 P2045 was less than 20 Gy, treatment with escalating doses of Re-188 P2045 was instituted. Three doses were evaluated 30 mCi/m2, 60 mCi/m2, and 90 mCi/m2. A single dose of Re-188 P2045 was allowed. Dose-limiting toxicity was defined as > or = grade 3 nonhematologic toxicity or grade 4 hematologic toxicity. Fifteen patients were enrolled. The median age was 61 years. Fourteen patients had > or = 2 prior chemotherapy regimens. All were imaged with Tc-99m P2045, eight patients received Re-188 P2045. The most common toxicity was mild lymphopenia. The trial was halted at the 90 mCi/m2 level when three patients were projected to have renal radiation doses above 20 Gy. The monoclonal antibody was not determined, and no responses were seen. Five of the eight patients (62.5%, 95% CI: 24-91%) had stable disease for at least 8 weeks, all of whom entered the study with progressive disease. Median overall survival was 11.5 months. This trial demonstrated that Re-188 P2045 was well tolerated. Tc-99m P2045 imaging allows identification of patients who may benefit from this treatment. Although responses were not seen, survival for these heavily pretreated patients is interesting and merits further research.

Journal of The Chemical Society-perkin Transactions 1, 1982

ABSTRACT 3β-Acetoxy-5α,6β-dichloropregn-16-en-20-one (1), on treatment with elemental fluorine at... more ABSTRACT 3β-Acetoxy-5α,6β-dichloropregn-16-en-20-one (1), on treatment with elemental fluorine at low temperature, gave the 16α,17α-difluoro-adduct (2) and, by rearrangement, the 13α,16α-difluoro-17β-methyl derivative (3). The adduct (2) was subsequently converted via a short, efficient synthetic sequence into 16α,17α-difluoroprogesterone (5). In contrast, fluorination of 21-acetoxypregna-1,4,16-triene-3,11,20-trione (6) afforded the corresponding 16α,17α-difluoro-adduct (8) in low yield. Similarly, androsta-1,4,6-triene-3,17-dione (9) was converted into the 6α,7α-difluoro-adduct (11). Fluorination with CF3OF led to an increased yield of the adduct (11) and also afforded the 6α-trifluoromethoxy-7α-fluoro-adduct (12). Dehydrofluorination of the latter gave 6-trifluoromethoxyandrosta-1,4,6-triene-3,17-dione (13). 21-Acetoxy-11β,17α-dihydroxypregna-1,4,6-triene-3,20-dione (5) was prepared by stepwise dehydrogenation of cortisol acetate (14). Subsequent low temperature treatment with CF3OF resulted in two major products, formulated as the adducts (17) and (18).

Journal of The Chemical Society-perkin Transactions 1, 1982

ABSTRACT Treatment of the N-methylnitrone (1b) of dichlorisone acetate (E–Z-mixture) with toluene... more ABSTRACT Treatment of the N-methylnitrone (1b) of dichlorisone acetate (E–Z-mixture) with toluene-p-sulphonyl chloride in pyridine in the presence of water gave dichlorisone acetate (1a)(88%). In the presence of hydrogen sulphide, however, the nitrone was deoxygenated to give the corresponding imine (1c), which on prolonged reaction with hydrogen sulphide in pyridine afforded the corresponding 1,4-diene-3-thione (1d). Similarly prepared were the unstable imines (2d), (3c), and (4c), which were smoothly converted into the corresponding thiones (2e), (3d), and (4d), respectively. In the absence of strong nucleophiles, dichlorisone acetate nitrone (1b) was treated with toluene-p-sulphonyl chloride in pyridine to give the corresponding trienimine (1g)(45%). Under similar conditions, however, prednisolone-21-propionate nitrone (3b) gave the 2-p-tolylsulphonyloxy-derivative (3e) as the major product. Separate treatment of both Z- and E-isomers of dehydrotestosterone acetate nitrone [(2b) and (2c)] afforded, in both cases, the 2-p-tolylsulphonyloxy-derivative (2g)(25%), whereas betamethasone nitrone (4b) gave a mixture of the 2-p-tolylsulphonyloxy-dienimine (4f) and the trienimine (4h) in low yield.

Nuclear Medicine and Biology, 2007

We report here the results of studies on the in vitro receptor binding affinity, in vivo tumor up... more We report here the results of studies on the in vitro receptor binding affinity, in vivo tumor uptake and biodistribution of two ""re labeled peptides. Methods: Peptides P587 and P829 were synthe sized by N-a-Fmoc peptide chemistry, purified by reversed-phase HPLC and characterized by fast-atom bombardment mass spectrometry. The peptides were labeled with 99mTcby ligand exchange from 99mTc-glucoheptonate. In vitro somatostatin receptors (SSTR)binding affinities of P587, P829 and their oxorhenium complexes, [DTPAJoctreotide and ln-[DTPA]octreotide were determined in an inhibition assay using AR42J rat pancreatic tumor cell membranes and 125l-[Tyr3]somatostatin-14 as the probe. In vivo single-and dual-tracer studies of ""Tc peptides and 111ln-[DTPA]octreotide were carried out using Lewis rats bearing CA20948 rat pancreatic tumor implants. Results: Technetium-99m-P587 and 99rrTc-P829 of high-specific activity (>60 Ci (2.2 TBq)/mmole) were prepared in >90% radiochemical yield. P587 and P829 had a Ki = 2.5 n/Wand 10 n/W, respectively.

The diagnosis of recurrent deep vein thrombosis (DVT) is challenging. Imaging with radiolabeled p... more The diagnosis of recurrent deep vein thrombosis (DVT) is challenging. Imaging with radiolabeled peptides offers a new approach for detecting acute DVT. Technetium Tc 99m ((99m)Tc)-apcitide binds with high affinity and specificity to the glycoprotein IIb/IIIa receptors expressed on activated platelets and, therefore, (99m)Tc-apcitide scintigraphy should be negative with residual abnormalities caused by old, inactive thrombi and positive with new, active thrombi. In a prospective multicenter study, (99m)Tc-apcitide imaging was performed on 38 patients with a newly diagnosed first DVT (group 1) and 40 patients with previous DVT, symptoms of postthrombotic syndrome, and chronic intraluminal abnormalities on ultrasonography (group 2). Images were interpreted in a blinded fashion by 2 experts and by newly trained nuclear medicine physicians. The sensitivity and specificity of (99m)Tc-apcitide were determined by calculating the proportion of scans in group 1 patients that were read as "positive for acute DVT" and the proportion of scans in group 2 patients that were read as "negative for acute DVT," respectively. When read by 2 experts, ( 99m)Tc-apcitide had a sensitivity of 92% for both readers and specificities of 82% and 90%. Agreement between the experts was excellent. However, the accuracy and interreader agreement for newly trained nuclear medicine physicians were lower. Technetium Tc 99m-apcitide scintigraphy has potential utility in suspected recurrent DVT because it detects most acute thrombi and has few false-positive results in patients with previous DVT. However, the accuracy appears to depend on the training and experience of the interpreters.

Journal of Medicinal Chemistry, 1996

Platelet-specific compounds which are radiolabeled with gamma-emitting radionuclides may be parti... more Platelet-specific compounds which are radiolabeled with gamma-emitting radionuclides may be particularly useful for the noninvasive in vivo detection of thrombi. The synthesis of peptides which are potent inhibitors of platelet aggregation and which contain a chelator for the radionuclide technetium-99m are described. The target compounds were designed such that stable, oxotechnetium(V) species could be prepared where the site of metal coordination was well defined. A strategy was employed where the pharmacophore-Arg-Gly-Asp-(RGD), or RGD mimetic, was constrained in a ring which was formed by the S-alkylation of a cysteine residue with an N-terminal chloroacetyl group. Binding affinities were enhanced by the replacement of arginine with the arginine mimetics S-(3-aminopropyl)cysteine and 4-amidinophenylalanine. Further enhancements could be obtained by the synthesis of oligomers which contained two or more rings containing receptor binding regions. The increase in binding affinity seen was more than that expected from a simple stoichiometric increase of pharmacophore. The most potent compounds described had IC50s of approximately 0.03 microM for the inhibition of human platelet aggregation. Two of the more potent peptides (P280 and P748) were labeled with technetium-99m and assessed in a canine thrombosis model. The 99m Tc complexes of the peptides prepared in this work hold promise as thrombus imaging agents due to their high receptor binding affinity, ease of preparation, and expected rapid pharmacokinetics.

Journal of Medicinal Chemistry, 1996

The synthesis of peptides which possess a high affinity for the somatostatin receptor and contain... more The synthesis of peptides which possess a high affinity for the somatostatin receptor and contain a chelator for the radionuclide technetium-99m is described. The target compounds were designed such that they would form stable, oxotechnetium(V) chelate complexes in which the Oxorhenium(V) chelate complexes of these peptides were prepared as nonradioactive surrogates for the technetium complexes. Peptide oxorhenium complexes and Tc-99m complexes eluted closely upon HPLC analysis. The receptor-binding affinities of both the free and rhenium-coordinated species were measured in vitro. The binding affinities of the free peptides (Ki's in the 0.25 - 10 nM range) compared favorably with [DTPA]octreotide (Ki = 1.6 nM), which, as the indium-111 complex, is already approved for somatostatin receptor (SSTR)-expressing tumor imaging in the United States and Europe. Furthermore, the rhenium-coordinated peptides had binding affinities which, in many cases, were higher than those of the corresponding free peptides, with several complexes having a Ki's of 0.1 nM. Some of the more potent SSTR-binding peptides were labeled with technetium-99m and assessed in an in vivo study with tumor-bearing rats. The 99m Tc-labeled peptides prepared in this study should be useful as SSTR-expressing tumor-imaging agents due to their high SSTR-binding affinities, ease of preparation, and, because they are low molecular weight peptides, expected pharmacokinetics characterized by rapid tracer excretion from the body resulting in high-contrast images.

American Journal of Therapeutics, 1995

We have previously shown that after administration of (123)I-SP-4 (a synthetic ApoB peptide fragm... more We have previously shown that after administration of (123)I-SP-4 (a synthetic ApoB peptide fragment) to Watanabe heritable hyperlipidemic (WHHL) rabbits that foci of tracer uptake can be identified by external gamma camera imaging which correspond to regions of the aortas found to contain abundant atherosclerotic lesions at postmortem evaluation. Because (99m)Tc is preferred over (123)I for scintigraphic imaging, we prepared a (99m)Tc-labeled form of the SP-4 peptide, designated (99m)Tc-P199. To assess the feasibility of detecting atherosclerotic lesions using (99m)Tc-P199 and to compare the relative uptake of the (99m)Tc-labeled and radioiodinated peptides by such lesions, an admixture of (99m)Tc-199 and (125)I-SP-4 was administered to 11 WHHL and 2 normal rabbits. These animals were imaged for up to 3 h and were sacrificed 3--4 h after injection. The extent of aortic lesion involvement and radiotracer uptake were quantitatively compared by planimetric analysis of photographs of the endothelial surface, (99m)Tc-P199 ex vivo images and (125)I-SP-4 autoradiograms of the excised aortas. Pairwise correlation coefficients for planimetric analysis were as follows: photographs versus ex vivo images, r = 0.83, p = 0.003; photographs versus autoradiograms, r = 0.87, p = 0.001; ex vivo images versus autoradiograms, r = 0.83, p = 0.003. (99m)Tc-199 in vivo gamma camera images revealed relatively weak focal aortic uptake in 8 of 11 WHHL rabbits manifesting aortic lesions, and focal carotid artery uptake in 4 of 6 WHHL rabbits manifesting carotid lesions. Neither aortic nor carotid foci were visualized in the normal rabbits. We conclude that (99m)Tc-199 localizes specifically in atherosclerotic lesions and may be useful for external imaging of atherosclerosis.

Journal of Medicinal Chemistry, 2007

Somatostatin derivative peptides previously designed for radiodiagnostic purposes (99mTc P829 or ... more Somatostatin derivative peptides previously designed for radiodiagnostic purposes (99mTc P829 or 99mTc depreotide) were reoptimized for radiotherapy of tumors with rhenium radioisotopes. An optimized pharmacophore peptide P1839 was derived by in vitro binding affinity assay to AR42J rat pancreatic tumor cell membranes. Peptides with chelating domains and their oxorhenium(V) complexes were tested in vitro for binding to NCI H69 human SCLC tumor membranes. Further optimization entailed radiolabeling with 99mTc and biodistribution in an AR42J xenograft mouse model. Kidney uptake was decreased substantially by removing positively charged residues. Neutral N3S diamide amine thiol chelators with no adjacent positive charges had the best overall properties. Substituting an aromatic amino acid into the chelator approximately doubled the tumor uptake. The final optimized peptide P2045 (39) radiolabeled with 99mTc exhibited increased tumor uptake ( approximately 25 %ID/g at 1.5 h), lower kidney uptake ( approximately 4.8 %ID/g at 1.5 h), and extensive urinary excretion (59 %ID at 1.5 h). Finally, comparison biodistribution studies between 99mTc and 188Re (39) showed a good correlation between the two metal complexes and demonstrated prolonged tumor retention (> or =24 h).

The objective of this work was the preclinical evaluation of ""Tc-P280, a """Tc-labeled peptide h... more The objective of this work was the preclinical evaluation of ""Tc-P280, a """Tc-labeled peptide having high affinity and specificity for the GPIIb/llla receptor expressed on activated platelets, for use as a thrombus imaging agent. Methods: The affinity and specificity of P280 peptide for the GPIIb/llla receptor was assessed by the inhibition of ADP-stimulated human platelet aggregation, the inhibi tion of the binding of fibrinogen to the GPIIb/llla receptor and the inhibition of the binding of vitronectin to the vitronectin receptor. P280 peptide was radiolabeled with 99mTcby ligand exchange using 99mTc-glucoheptonate. The ability of 99mTc-P280 to detect thrombi in vivo was assessed using a canine venous thrombosis model and the biodistribution of 99mTc-P280 was determined in rats and rabbits. Results: P280 peptide had an IC50 of 79 nM for the inhibition of aggregation of human platelets in platelet rich plasma, an ICgo of 6.8 nM for the inhibition of fibrinogen binding to the GPIIb/llla receptor and an ICso of 13 /nM for the inhibition of vitronectin binding to the vitronectin receptor, showing the high in vitro receptor binding affinity and specificity of the peptide. 99mTc-P280 was readily prepared in >90% radiochemical yield and purity and provided images of femoral vein thrombi in the canine model by 1 hr postinjection (thrombus-to-blood ratio of 4.4 and thrombus-tomuscle ratio of 11 at 4 hr). Dog, rat and rabbit studies all showed rapid clearance of the radiotracer from the blood and rapid renal excretion. Conclusion: The combination of high in vitro receptorbinding affinity and specificity, in vivo thrombus imaging and fast clearance support the evaluation of 99mTc-P280 as a clinical imag ing agent.

surface provides the basis for the successful clinical use of radiolabeled ligands for the in viv... more surface provides the basis for the successful clinical use of radiolabeled ligands for the in vivo localization of tumor sites. We have characterized the in vitro binding properties of the novel SSTR ligand "mTc-P829 using primary human tumors (carcinoids, breast cancers, intestinal adenocarcinomas, pheochromocytomas, small cell and non-small cell lung cancer, and melanomas; n = 28), various tumor cell lines, and COS7 cells transfected with the human SSTR (hSSTR) subtypes 1, 2, 3, 4, and 5. """Tc-P829 bound to primary tumor cells and tumor cell lines with high affinity and high capacity. The dissociation constants (A,,I ranged between 1 and 20 IIM. '"""Tc-1'829 also bound with high affinity to the transfected hSSTR2 (Ka, 2.5 nM), hSSTRS (Ad, 2 nM), and hSSTR3 (K¿,1.5 nM). Binding of "'""Tt-PH29 to hSSTR3 was found to be displaceable by unla-

Journal of The American College of Cardiology, 1995

has considerable potential as a clinical imaging agent for the detection of venous thromboembolism.

Nuclear Medicine Communications, 2000

Bioconjugate Chemistry, 1990

Bifunctional chelators for labeling antibodies with 99mTc based on the N3S core of (mercaptoacety... more Bifunctional chelators for labeling antibodies with 99mTc based on the N3S core of (mercaptoacetyl)-triglycine having ester or amide linking moieties were synthesized and site-specifically attached to the sulfhydryl groups of the Fab' fragment of antimyosin. Protein labeling was quantitative after 15 min; postlabeling purification was not necessary. The radiolabeled conjugates exhibited no loss of immunoreactivity. Under basic conditions, the ester-linked conjugate lost 95% of the radiolabel in the form of the 99mTc complex of (mercaptoacetyl)triglycine as determined by RP-HPLC, while the radioactivity in the amide-linked conjugate remained completely bound to the protein. In a mouse biodistribution study, the ester-linked conjugate showed a 2-fold enhancement in clearance from the kidney when compared to the amide-linked product.

We report here the results of studies on the in vitro receptor binding affinity, in vivo tumor up... more We report here the results of studies on the in vitro receptor binding affinity, in vivo tumor uptake and biodistribution of two ""re labeled peptides. Methods: Peptides P587 and P829 were synthe sized by N-a-Fmoc peptide chemistry, purified by reversed-phase HPLC and characterized by fast-atom bombardment mass spectrometry. The peptides were labeled with 99mTcby ligand exchange from 99mTc-glucoheptonate. In vitro somatostatin receptors (SSTR)binding affinities of P587, P829 and their oxorhenium complexes, [DTPAJoctreotide and ln-[DTPA]octreotide were determined in an inhibition assay using AR42J rat pancreatic tumor cell membranes and 125l-[Tyr3]somatostatin-14 as the probe. In vivo single-and dual-tracer studies of ""Tc peptides and 111ln-[DTPA]octreotide were carried out using Lewis rats bearing CA20948 rat pancreatic tumor implants. Results: Technetium-99m-P587 and 99rrTc-P829 of high-specific activity (>60 Ci (2.2 TBq)/mmole) were prepared in >90% radiochemical yield. P587 and P829 had a Ki = 2.5 n/Wand 10 n/W, respectively.

American Journal of Therapeutics, 1996

I-125 labeled SP4 is a synthetic oligopeptide derived from apolipoprotein B of low-density lipopr... more I-125 labeled SP4 is a synthetic oligopeptide derived from apolipoprotein B of low-density lipoprotein that has been shown to localized in atherosclerotic plaques in experimental animals. However, its biodistribution and mechanism of localization need to be further elucidated. Twenty-four cholesterol-fed (CF) and 20 normal (NL) New Zealand White rabbits were injected with I-125-SP4 and killed 15 to 30 min (6 NL; 6 CF) or 2 h (14 NL; 18 CF) later. We obtained aortic autoradiograms and activity concentrations (% injected dose/gm) in aortic segments and other tissues. The uptake of I-125-SP4 was higher in CF than in NL rabbits in all aortic segments (p < 0.05). I-125-SP4 was cleared rapidly in both CF and NL rabbits with 60 to 70% of the injected dose cleared from the blood by 1 h. No statistically significant differences in radiotracer biodistribution were observed between NL and CF rabbits although activity tended to be higher in the liver, gallbladder, and intestine in NL rabbits and in the kidney and spleen in CF rabbits. Silver grains were distributed mainly on foam cells of the fatty streaks in aortic microautoradiograms from two additional rabbits that had been injected with I-125-SP4. There were 23,518 plus minus 15,878 (SD) grains/mm(2) in fatty plaques but only 14,669 plus minus 11,035 grains/mm(2) in media muscle (p < 0.0001 [9 sections, 17 areas evaluated] in an atherosclerotic animal) in injected animals and 13,439 plus minus 5,565 grains/mm(2) in media muscle (two sections, four areas) in the normal control animals (NS versus media of atherosclerotic animal). I-125-SP4 specifically localizes in aortic atherosclerotic plaques in CF rabbits. There is no significant difference in tissue distribution between normal and CF rabbits except in the aorta. Preliminarily, it appears that the site of tracer uptake is on foam cells and this suggests the possibility of relative specificity for fatty plaque.

European Journal of Nuclear Medicine, 1986

Technetium-99m hexakis (t-butylisonitrile) technetium (I) (99mTc-TBI) is a new myocardial perfusi... more Technetium-99m hexakis (t-butylisonitrile) technetium (I) (99mTc-TBI) is a new myocardial perfusion imaging agent. To determine its potential in the evaluation of myocardial infarction, 15 patients with suspected or confirmed acute infarction were studied by bedside imaging in the coronary care unit. Good-quality planar scintigrams in multiple projections were obtained in 13 patients. Gated perfusion studies were performed in 14 patients, and for comparison 13 of these were restudied 24–72 h later by standard gated equilibrium blood pool radionuclide ventriculography. Conventional and planar scintigraphic criteria for myocardial infarction (acute or old) agreed in 12 (92%) patients (k=0.81, pk=0.49, p99mTc-TBI scintigraphy were in complete agreement for 25 (64%) of 39 left ventricular segments (k=0.35, p99mTc-TBI scintigraphy. Therefore, 99mTc-TBI scintigraphy can readily provide data on regional myocardial perfusion and wall motion, permitting detection and localization of areas of myocardial infarction. The superior imaging properties, ready availability and low cost of 99mTc point to the considerable potential value of 99mTc-TBI in assessing patients with suspected or confirmed myocardial infarction.

Inorganic Chemistry, 1988

The coordination chemistry of amide and thiolate ligands has a strong basis in both biology and c... more The coordination chemistry of amide and thiolate ligands has a strong basis in both biology and chemistry, and reviews have been dedicated to the field. 2 We are particularly interested in this area of chemistry as it pertains to the preparation of new classes of chelate ...