Modification of Biodistribution and Brain Uptake of Copper Bis(thiosemicarbazonato) Complexes by the Incorporation of Amine and Polyamine Functional Groups.

The synthesis of new bis(thiosemicarbazonato)copper(II) complexes featuring polyamine substituents via selective transamination reactions is presented. Polyamines of different lengths, with different ionizable substituent groups, were used to modify and adjust the hydrophilic/lipophilic balance of the copper complexes. The new analogues were radiolabeled with copper-64 and their lipophilicities estimated using distribution coefficients. The cell uptake of the new polyamine complexes was investigated with preliminary in vitro biological studies using a neuroblastoma cancer cell line. The in vivo biodistribution of three of the new analogues was investigated in vivo in mice using positron-emission tomography imaging, and one of the new complexes was compared to [64Cu]Cu(atsm) in an A431 squamous cell carcinoma xenograft model. Modification of the copper complexes with various amine-containing functional groups alters the biodistribution of the complexes in mice. One complex, with a pendent ( N, N-dimethylamino)ethane functional group, displayed tumor uptake similar to that of [64Cu]Cu(atsm) but higher brain uptake, suggesting that this compound has the potential to be of use in the diagnostic brain imaging of tumors and neurodegenerative diseases.

Quantitative and qualitative analysis of [(18)F]FDG and [(18)F]FAZA positron emission tomography of head and neck cancers and associations with HPV status and treatment outcome.

PURPOSE: While methods for imaging tumor hypoxia with positron emission tomography (PET) have been developed, optimal methods for interpreting and utilizing these datasets in the clinic remain unclear. In this study, we analyzed hypoxia PET images of head and neck cancer patients and compared imaging metrics with human papilloma virus (HPV) status and clinical outcome. METHODS: Forty-one patients treated as part of a phase III trial of the hypoxic cytotoxin tirapazamine (TROG 02.02) were imaged with PET using fluorodeoxyglucose (FDG) and fluoroazomycin arabinoside (FAZA). FDG and FAZA PET images were interpreted qualitatively and quantitatively, and compared with tumor T stage, HPV status, and treatment outcome using multivariate statistics. RESULTS: PET signals in the tumor and lymph nodes exhibited significant intra- and inter-patient variability. The FAZA hypoxic volume demonstrated a significant correlation with tumor T stage. PET-hypoxic tumors treated with cisplatin exhibited significantly worse treatment outcomes relative to PET-oxic tumors or PET-hypoxic tumors treated with tirapazamine. CONCLUSION: Quantitative analysis of FAZA PET yielded metrics that correlated with clinical T stage and were capable of stratifying patient outcome. These results encourage further development of this technology, with particular emphasis on establishment of robust quantitative methods.

InterProScan 5: genome-scale protein function classification.

MOTIVATION: Robust large-scale sequence analysis is a major challenge in modern genomic science, where biologists are frequently trying to characterize many millions of sequences. Here, we describe a new Java-based architecture for the widely used protein function prediction software package InterProScan. Developments include improvements and additions to the outputs of the software and the complete reimplementation of the software framework, resulting in a flexible and stable system that is able to use both multiprocessor machines and/or conventional clusters to achieve scalable distributed data analysis. InterProScan is freely available for download from the EMBl-EBI FTP site and the open source code is hosted at Google Code.

Harmonizing FDG PET quantification while maintaining optimal lesion detection: prospective multicentre validation in 517 oncology patients.

PURPOSE: Point-spread function (PSF) or PSF + time-of-flight (TOF) reconstruction may improve lesion detection in oncologic PET, but can alter quantitation resulting in variable standardized uptake values (SUVs) between different PET systems. This study aims to validate a proprietary software tool (EQ.PET) to harmonize SUVs across different PET systems independent of the reconstruction algorithm used. METHODS: NEMA NU2 phantom data were used to calculate the appropriate filter for each PSF or PSF+TOF reconstruction from three different PET systems, in order to obtain EANM compliant recovery coefficients. PET data from 517 oncology patients were reconstructed with a PSF or PSF+TOF reconstruction for optimal tumour detection and an ordered subset expectation maximization (OSEM3D) reconstruction known to fulfil EANM guidelines. Post-reconstruction, the proprietary filter was applied to the PSF or PSF+TOF data (PSFEQ or PSF+TOFEQ). SUVs for PSF or PSF+TOF and PSFEQ or PSF+TOFEQ were compared to SUVs for the OSEM3D reconstruction. The impact of potential confounders on the EQ.PET methodology including lesion and patient characteristics was studied, as was the adherence to imaging guidelines. RESULTS: For the 1380 tumour lesions studied, Bland-Altman analysis showed a mean ratio between PSF or PSF+TOF and OSEM3D of 1.46 (95%CI: 0.86-2.06) and 1.23 (95%CI: 0.95-1.51) for SUVmax and SUVpeak, respectively. Application of the proprietary filter improved these ratios to 1.02 (95%CI: 0.88-1.16) and 1.04 (95%CI: 0.92-1.17) for SUVmax and SUVpeak, respectively. The influence of the different confounding factors studied (lesion size, location, radial offset and patient's BMI) was less than 5%. Adherence to the European Association of Nuclear Medicine (EANM) guidelines for tumour imaging was good. CONCLUSION: These data indicate that it is not necessary to sacrifice the superior lesion detection and image quality achieved by newer reconstruction techniques in the quest for harmonizing quantitative comparability between PET systems.

High-resolution imaging of pulmonary ventilation and perfusion with 68Ga-VQ respiratory gated (4-D) PET/CT.

PURPOSE: Our group has previously reported on the use of (68)Ga-ventilation/perfusion (VQ) PET/CT scanning for the diagnosis of pulmonary embolism. We describe here the acquisition methodology for (68)Ga-VQ respiratory gated (4-D) PET/CT and the effects of respiratory motion on image coregistration in VQ scanning. METHODS: A prospective study was performed in 15 patients with non-small-cell lung cancer. 4-D PET and 4-D CT images were acquired using an infrared marker on the patient's abdomen as a surrogate for breathing motion following inhalation of Galligas and intravenous administration of (68)Ga-macroaggregated albumin. Images were reconstructed with phase-matched attenuation correction. The lungs were contoured on CT and PET VQ images during free-breathing (FB) and at maximum inspiration (Insp) and expiration (Exp). The similarity between PET and CT volumes was measured using the Dice coefficient (DC) comparing the following groups; (1) FB-PET/CT, (2) InspPET/InspCT, (3) ExpPET/Exp CT, and (4) FB-PET/AveCT. A repeated measures one-way ANOVA with multiple comparison Tukey tests were performed to evaluate any difference between the groups. Diaphragmatic motion in the superior-inferior direction on the 4-D CT scan was also measured. RESULTS: 4-D VQ scanning was successful in all patients without additional acquisition time compared to the nongated technique. The highest volume overlap was between ExpPET and ExpCT and between FB-PET and AveCT with a DC of 0.82 and 0.80 for ventilation and perfusion, respectively. This was significantly better than the DC comparing the other groups (0.78-0.79, p < 0.05). These values agreed with a visual inspection of the images with improved image coregistration around the lung bases. The diaphragmatic motion during the 4-D CT scan was highly variable with a range of 0.4-3.4 cm (SD 0.81 cm) in the right lung and 0-2.8 cm (SD 0.83 cm) in the left lung. Right-sided diaphragmatic nerve palsy was observed in 3 of 15 patients. CONCLUSION: (68)Ga-VQ 4-D PET/CT is feasible and the blurring caused by respiratory motion is well corrected with 4-D acquisition, which principally reduces artefact at the lung bases. The images with the highest spatial overlap were the combined expiration phase or FB PET and average CT. With higher resolution than SPECT/CT, the PET/CT technique has a broad range of potential clinical applications including diagnostic algorithms for patients with suspected pulmonary embolism, preoperative evaluation of regional lung function and improving assessment or understanding of pulmonary physiology in the vast range of pulmonary diseases.

InterPro in 2011: new developments in the family and domain prediction database.

InterPro (http://www.ebi.ac.uk/interpro/) is a database that integrates diverse information about protein families, domains and functional sites, and makes it freely available to the public via Web-based interfaces and services. Central to the database are diagnostic models, known as signatures, against which protein sequences can be searched to determine their potential function. InterPro has utility in the large-scale analysis of whole genomes and meta-genomes, as well as in characterizing individual protein sequences. Herein we give an overview of new developments in the database and its associated software since 2009, including updates to database content, curation processes and Web and programmatic interfaces.

Diagnostic imaging agents for Alzheimer's disease: copper radiopharmaceuticals that target Aß plaques.

One of the pathological hallmarks of Alzheimer's disease is the presence of amyloid-ß plaques in the brain and the major constituent of these plaques is aggregated amyloid-ß peptide. New thiosemicarbazone-pyridylhydrazine based ligands that incorporate functional groups designed to bind amyloid-ß plaques have been synthesized. The new ligands form stable four coordinate complexes with a positron-emitting radioactive isotope of copper, (64)Cu. Two of the new Cu(II) complexes include a functionalized styrylpyridine group and these complexes bind to amyloid-ß plaques in samples of post-mortem human brain tissue. Strategies to increase brain uptake by functional group manipulation have led to a (64)Cu complex that effectively crosses the blood-brain barrier in wild-type mice. The new complexes described in this manuscript provide insight into strategies to deliver metal complexes to amyloid-ß plaques.

Hypometabolism precedes limbic atrophy and spontaneous recurrent seizures in a rat model of TLE.

PURPOSE: Temporal hypometabolism on fluorodeoxyglucose positron emission tomography (FDG-PET) is a common finding in patients with drug-resistant temporal lobe epilepsy (TLE). The pathophysiology underlying the hypometabolism, including whether it reflects a primary epileptogenic process, or whether it occurs later as result of limbic atrophy or as a result of chronic seizures, remains unknown. This study aimed to investigate the ontologic relationship among limbic atrophy, histological changes, and hypometabolism in rats. METHODS: Serial in vivo imaging with FDG-PET and volumetric magnetic resonance imaging (MRI) was acquired before and during the process of limbic epileptogenesis resulting from kainic acid-induced status epilepticus in the rat. The imaging data were correlated with histologic measures of cell loss, and markers of astrogliosis (glial fibrillary acid protein [GFAP]), synaptogenesis (synaptophysin), glucose transporter 1 (Glut1) and energy metabolism (cytochrome oxidase C), on brains of the animals following the final imaging point. KEY FINDINGS: Hippocampal hypometabolism on FDG-PET was found to be present 24 h following status epilepticus, tending to lessen by 1 week and then become more marked again following the onset of spontaneous seizures. Atrophy of limbic structures was evident from 7 days post-SE, becoming progressively more marked on serial MRI over subsequent weeks. No relationship was observed between the severity of MRI-detected atrophy or CA1 pyramidal cell loss and the degree of the hypometabolism on FDG-PET. However, an inverse relationship was observed between hypometabolism and increased expression of the Glut1 and synaptophysin in the hippocampus. SIGNIFICANCE: These findings demonstrate that hypometabolism occurs early in the processes of limbic epileptogenesis and is not merely a consequence of pyramidal cell loss or the progressive atrophy of limbic brain structures that follow. The hypometabolism may reflect cellular mechanisms occurring early during epileptogenesis in addition to any effects of the subsequent recurrent spontaneous seizures.

Compliance with PET acquisition protocols for therapeutic monitoring of erlotinib therapy in an international trial for patients with non-small cell lung cancer.

PURPOSE: The Response Evaluation Criteria in Solid Tumors (RECIST) are widely used but have recognized limitations. Molecular imaging assessments, including changes in (18)F-deoxyglucose (FDG) or (18)F-deoxythymidine (FLT) uptake by positron emission tomography (PET), may provide earlier, more robust evaluation of treatment efficacy. METHODS: A prospective trial evaluated on-treatment changes in FDG and FLT PET imaging among patients with relapsed or recurrent non-small cell lung cancer treated with erlotinib to assess the relationship between PET-evaluated response and clinical outcomes. We describe an audit of compliance with the study imaging charter, to establish the feasibility of achieving methodological consistency in a multicentre setting. RESULTS: Patients underwent PET scans at baseline and approximately day 14 and day 56 of treatment (n = 73, 66 and 51 studies, and n = 73, 63 and 50 studies for FDG PET and FLT PET, respectively). Blood glucose levels were within the target range for all FDG PET scans. Charter-specified uptake times were achieved in 86% (63/73) and 89% (65/73) of baseline FDG and FLT scans, respectively. On-treatment scans were less consistent: 72% (84/117) and 68% (77/113), respectively, achieved the target of ±5 min of baseline uptake time. However, 96% (112/117) and 94% (106/113) of FDG and FLT PET studies, respectively, were within ±15 min. Bland-Altman analysis of intra-individual hepatic average standardized uptake value (SUV(ave)), to assess reproducibility, showed only a small difference in physiological uptake (-0.006 ± 0.224 in 118 follow-up FDG scans and 0.09 ± 0.81 in 111 follow-up FLT scans). CONCLUSION: It is possible to achieve high reproducibility of scan acquisition methodology, provided that strict imaging compliance guidelines are mandated in the study protocol.

The GOA database in 2009--an integrated Gene Ontology Annotation resource.

The Gene Ontology Annotation (GOA) project at the EBI (http://www.ebi.ac.uk/goa) provides high-quality electronic and manual associations (annotations) of Gene Ontology (GO) terms to UniProt Knowledgebase (UniProtKB) entries. Annotations created by the project are collated with annotations from external databases to provide an extensive, publicly available GO annotation resource. Currently covering over 160 000 taxa, with greater than 32 million annotations, GOA remains the largest and most comprehensive open-source contributor to the GO Consortium (GOC) project. Over the last five years, the group has augmented the number and coverage of their electronic pipelines and a number of new manual annotation projects and collaborations now further enhance this resource. A range of files facilitate the download of annotations for particular species, and GO term information and associated annotations can also be viewed and downloaded from the newly developed GOA QuickGO tool (http://www.ebi.ac.uk/QuickGO), which allows users to precisely tailor their annotation set.

InterPro: the integrative protein signature database.

The InterPro database (http://www.ebi.ac.uk/interpro/) integrates together predictive models or 'signatures' representing protein domains, families and functional sites from multiple, diverse source databases: Gene3D, PANTHER, Pfam, PIRSF, PRINTS, ProDom, PROSITE, SMART, SUPERFAMILY and TIGRFAMs. Integration is performed manually and approximately half of the total approximately 58,000 signatures available in the source databases belong to an InterPro entry. Recently, we have started to also display the remaining un-integrated signatures via our web interface. Other developments include the provision of non-signature data, such as structural data, in new XML files on our FTP site, as well as the inclusion of matchless UniProtKB proteins in the existing match XML files. The web interface has been extended and now links out to the ADAN predicted protein-protein interaction database and the SPICE and Dasty viewers. The latest public release (v18.0) covers 79.8% of UniProtKB (v14.1) and consists of 16 549 entries. InterPro data may be accessed either via the web address above, via web services, by downloading files by anonymous FTP or by using the InterProScan search software (http://www.ebi.ac.uk/Tools/InterProScan/).

QuickGO: a web-based tool for Gene Ontology searching.

UNLABELLED: QuickGO is a web-based tool that allows easy browsing of the Gene Ontology (GO) and all associated electronic and manual GO annotations provided by the GO Consortium annotation groups QuickGO has been a popular GO browser for many years, but after a recent redevelopment it is now able to offer a greater range of facilities including bulk downloads of GO annotation data which can be extensively filtered by a range of different parameters and GO slim set generation. AVAILABILITY AND IMPLEMENTATION: QuickGO has implemented in JavaScript, Ajax and HTML, with all major browsers supported. It can be queried online at http://www.ebi.ac.uk/QuickGO. The software for QuickGO is freely available under the Apache 2 licence and can be downloaded from http://www.ebi.ac.uk/QuickGO/installation.html

Peptide Receptor Radionuclide Therapy with 67Cu-CuSarTATE Is Highly Efficacious Against a Somatostatin-Positive Neuroendocrine Tumor Model.

Peptide receptor radionuclide therapy (PRRT) using radiolabeled octreotate is an effective treatment for somatostatin receptor 2-expressing neuroendocrine tumors. The diagnostic and therapeutic potential of 64Cu and 67Cu, respectively, offers the possibility of using a single somatostatin receptor-targeted peptide conjugate as a theranostic agent. A sarcophagine cage amine ligand, MeCOSar (5-(8-methyl-3,6,10,13,16,19-hexaaza-bicyclo[6.6.6]icosan-1-ylamino)-5-oxopentanoic acid), conjugated to (Tyr3)-octreotate, called 64Cu-CuSarTATE, was demonstrated to be an imaging agent and potential prospective dosimetry tool in 10 patients with neuroendocrine tumors. This study aimed to explore the antitumor efficacy of 67Cu-CuSarTATE in a preclinical model of neuroendocrine tumors and compare it with the standard PRRT agent, 177Lu-LuDOTA-Tyr3-octreotate (177Lu-LuTATE). Methods: The antitumor efficacy of various doses of 67Cu-CuSarTATE in AR42J (rat pancreatic exocrine) tumor-bearing mice was compared with 177Lu-LuTATE. Results: Seven days after a single administration of 67Cu-CuSarTATE (5 MBq), tumor growth was inhibited by 75% compared with vehicle control. Administration of 177Lu-LuTATE (5 MBq) inhibited tumor growth by 89%. Survival was extended from 12 d in the control group to 21 d after treatment with both 67Cu-CuSarTATE and 177Lu-LuTATE. In a second study, the efficacy of fractionated delivery of PRRT was assessed, comparing the efficacy of 30 MBq of 67Cu-CuSarTATE or 177Lu-LuTATE, either as a single intravenous injection or as two 15-MBq fractions 2 wk apart. Treatment of tumors with 2 fractions significantly improved survival over delivery as a single fraction (67Cu-CuSarTATE: 47 vs. 36 d [P = 0.036]; 177Lu-LuTATE: 46 vs. 29 d [P = 0.040]). Conclusion: This study demonstrates that 67Cu-CuSarTATE is well tolerated in BALB/c nude mice and highly efficacious against AR42J tumors in vivo. Administration of 67Cu-CuSarTATE and 177Lu-LuTATE divided into 2 fractions over 2 wk was more efficacious than administration of a single fraction. The antitumor activity of 67Cu-CuSarTATE in the AR42J tumor model demonstrated the suitability of this novel agent for clinical assessment in the treatment of somatostatin receptor 2-expressing neuroendocrine tumors.

In-vivo imaging characteristics of two fluorinated flumazenil radiotracers in the rat.

PURPOSE: [(11)C]Flumazenil shows promise as a clinical and research PET radiotracer to image changes in GABA(A) central benzodiazepine receptor (cBZR), but its widespread use has been limited by practical limitations of [(11)C]. This study evaluated the imaging characteristics of two fluorinated PET radiotracers in rats in vivo: [(18)F]fluoroflumazenil ([(18)F]FFMZ) and [(18)F]flumazenil ([(18)F]FMZ). METHODS: PET acquisitions were performed on a small-animal scanner following injection of [(18)F]FFMZ in nine rats and [(18)F]FMZ in eight rats. The following treatments were investigated: (1) injection of the tracer dose, (2) presaturation then injection of the tracer dose, and (3) injection of the tracer dose followed by a displacement injection. Unchanged tracer was measured in plasma and brain structures in four animals 10 and 30 min after injection, and ex-vivo autoradiography was also performed. RESULTS: For both [(18)F]FFMZ and [(18)F]FMZ maximal brain activity peaked rapidly, and was highest in the hippocampus (1.12+/-0.06 SUV, 1.24+/-0.10 SUV, respectively), and lowest in the pons (1.00+/-0.07 SUV, 1.03+/-0.09 SUV, respectively). By 50 min after injection, maximal uptake for [(18)F]FFMZ and [(18)F]FMZ had decreased in the hippocampus to 18+/-3% and 80+/-1% (p<0.01), respectively. The presaturation and displacement studies showed a higher nonspecific component for [(18)F]FFMZ than for [(18)F]FMZ. Metabolite studies showed that at 30 min only 10% of the signal was from [(18)F]FFMZ in the brain. This nonspecific binding was apparent on autoradiography. In contrast, [(18)F]FMZ accounted for >70% of the signal in the brain, which resulted in well-defined regional binding on autoradiography. CONCLUSION: These results demonstrate that [(18)F]FMZ is a superior radiotracer to [(18)F]FFMZ for in-vivo PET imaging of the GABA(A)/cBZR, having slower metabolism and leading to lower concentrations of metabolites in the brain that results in a substantially better signal-to-noise ratio.

New developments in the InterPro database.

InterPro is an integrated resource for protein families, domains and functional sites, which integrates the following protein signature databases: PROSITE, PRINTS, ProDom, Pfam, SMART, TIGRFAMs, PIRSF, SUPERFAMILY, Gene3D and PANTHER. The latter two new member databases have been integrated since the last publication in this journal. There have been several new developments in InterPro, including an additional reading field, new database links, extensions to the web interface and additional match XML files. InterPro has always provided matches to UniProtKB proteins on the website and in the match XML file on the FTP site. Additional matches to proteins in UniParc (UniProt archive) are now available for download in the new match XML files only. The latest InterPro release (13.0) contains more than 13 000 entries, covering over 78% of all proteins in UniProtKB. The database is available for text- and sequence-based searches via a webserver (http://www.ebi.ac.uk/interpro), and for download by anonymous FTP (ftp://ftp.ebi.ac.uk/pub/databases/interpro). The InterProScan search tool is now also available via a web service at http://www.ebi.ac.uk/Tools/webservices/WSInterProScan.html.

Automated preparation of clinical grade [68Ga]Ga-DOTA-CP04, a cholecystokinin-2 receptor agonist, using iPHASE MultiSyn synthesis platform.

BACKGROUND: Gallium-68 ([68Ga]Ga) labelled radiopharmaceuticals have become a valuable tool in clinical practice using Positron Emission Tomography (PET). These agents are typically produced on-site owing to the short half-life of [68Ga]Ga (68 min), which hinders distant transportation and often cannot comply with Good Manufacturing Practice (GMP) in hospital environments due to limited resources or infrastructure constraints. Moreover, full blown GMP production of radiopharmaceuticals under development can be prohibitively expensive. [68Ga]Ga-DOTA-CP04 is a promising peptide for imaging neuroendocrine tumors overexpressing the cholecyctokinin-2 receptor. Automation is an integral process in ensuring the radiopharmaceuticals produced under non-GMP conditions are of a uniform quality for routine clinical use. Herein, we describe the development of an automation platform, the iPHASE MultiSyn radiosynthesizer, to produce 68Ga-labelled DOTA-CP04 for routine clinical provision. RESULTS: The use of the MultiSyn module for 68Ga-labelling of DOTA-CP04 was investigated. [68Ga]Ga-DOTA-CP04, was reproducibly prepared in high (> 70%) decay-corrected yields. [68Ga]Ga-DOTA-CP04 passed all predetermined acceptance criteria for human injection. CONCLUSIONS: [68Ga]Ga-DOTA-CP04 was produced effectively using the MultiSyn module in a consistent and reproducible manner suitable for human injection.

The cost-effective use of 18F-FDG PET in the presurgical evaluation of medically refractory focal epilepsy.

UNLABELLED: This study applied decision tree analysis to evaluate the sensitivity, specificity, and cost-effectiveness of clinical algorithms that incorporate 18F-FDG PET. METHODS: A cohort of 176 patients was studied. The localization rate, accuracy, therapeutic impact on the presurgical decision-making process, and correlation with the postsurgical outcome were assessed for the tests commonly performed for seizure localization. Decision tree sensitivity analysis compared 3 imaging strategies with a baseline strategy of medical therapy for all: video-electroencephalography monitoring (VEM)/MRI strategy, in which patients underwent VEM and brain MRI only, and +SPECT and +PET strategies, in which patients with an indeterminate VEM/MRI result underwent ictal SPECT or interictal 18F-FDG PET, respectively. RESULTS: The localization rates for VEM, MRI, 18F-FDG PET, ictal SPECT, and intracranial electroencephalography (EEG) were 62.2%, 35.8%, 75.0%, 60.0%, and 93.8%. The VEM/MRI strategy had the lowest cost per class I/II outcome, but the additional costs per class I/II outcome for the +PET and +SPECT strategies were always below the minimum reported cost savings for a class I/II outcome. There were no valid conditions in which the +SPECT strategy had a lower cost per class I/II outcome than the +PET strategy. Within the range of cost savings estimated to be associated with a class I/II outcome, all decision strategies produced net cost savings; however, these were significantly higher for the +PET and the +SPECT strategies. CONCLUSION: 18F-FDG PET is cost-effective in the presurgical evaluation, particularly when used in patients with a nonlocalizing or nonconcordant VEM or MRI result.

Cold Kit for Prostate-Specific Membrane Antigen (PSMA) PET Imaging: Phase 1 Study of 68Ga-Tris(Hydroxypyridinone)-PSMA PET/CT in Patients with Prostate Cancer.

68Ga-labeled urea-based inhibitors of the prostate-specific membrane antigen (PSMA), such as 68Ga-labeled N,N'-bis(2-hydroxybenzyl)ethylenediamine-N,N'-diacetic acid (HBED)-PSMA-11, are promising small molecules for targeting prostate cancer. A new radiopharmaceutical, 68Ga-labeled tris(hydroxypyridinone) (THP)-PSMA, has a simplified design for single-step kit-based radiolabeling. It features the THP ligand, which forms complexes with 68Ga3+ rapidly at a low concentration, at room temperature, and over a wide pH range, enabling direct elution from a 68Ge/68Ga generator into a lyophilized radiopharmaceutical kit in 1 step without manipulation. The aim of this phase 1 study was to assess the safety and biodistribution of 68Ga-THP-PSMA. Methods: Cohort A comprised 8 patients who had proven prostate cancer and were scheduled to undergo prostatectomy; they had Gleason scores of 7-10 and a mean prostate-specific antigen level of 7.8 µg/L (range, 5.4-10.6 µg/L). They underwent PET/CT after the administration of 68Ga-THP-PSMA. All patients proceeded to prostatectomy (7 with pelvic nodal dissection). Dosimetry from multi-time-point PET imaging was performed with OLINDA/EXM. Cohort B comprised 6 patients who had positive 68Ga-HBED-PSMA-11 PET/CT scanning results and underwent comparative 68Ga-THP-PSMA scanning. All patients were monitored for adverse events. Results: No adverse events occurred. In cohort A, 6 of 8 patients had focal uptake in the prostate (at 2 h: average SUVmax, 5.1; range, 2.4-9.2) and correlative 3+ staining of prostatectomy specimens on PSMA immunohistochemistry. The 2 68Ga-THP-PSMA scans with negative results had only 1+/2+ staining. The mean effective dose was 2.07E-02 mSv/MBq. In cohort B, 68Ga-THP-PSMA had lower physiologic background uptake than 68Ga-HBED-PSMA-11 (in the parotid glands, the mean SUVmax for 68Ga-THP-PSMA was 3.6 [compared with 19.2 for 68Ga-HBED-PSMA-11]; the respective corresponding values in the liver were 2.7 and 6.3, and those in the spleen were 2.7 and 10.5; P < 0.001 for all). In 5 of 6 patients, there was concordance in the number of metastases identified with 68Ga-HBED-PSMA-11 and 68Ga-THP-PSMA. Thirteen of 15 nodal abnormalities were subcentimeter. In 22 malignant lesions, the tumor-to-liver contrast with 68Ga-THP-PSMA was similar to that with 68Ga-HBED-PSMA (4.7 and 5.4, respectively; P = 0.15), despite a higher SUVmax for 68Ga-HBED-PSMA than for 68Ga-THP-PSMA (30.3 and 10.7, respectively; P < 0.01). Conclusion:68Ga-THP-PSMA is safe and has a favorable biodistribution for clinical imaging. Observed focal uptake in the prostate was localized to PSMA-expressing malignant tissue on histopathology. Metastatic PSMA-avid foci were also visualized with 68Ga-THP-PSMA PET. Single-step production from a Good Manufacturing Practice cold kit may enable rapid adoption.

Imaging of tumor hypoxia with [124I]IAZA in comparison with [18F]FMISO and [18F]FAZA--first small animal PET results.

PURPOSE: This study was performed to compare the 2-nitroimidazole derivatives [124I]IAZA, [18F]FAZA and well known [18F]FMISO in visualization of tumor hypoxia in a mouse model of human cancer using small animal PET. METHODS: PET imaging of female Balb/c nude mice bearing A431 tumors on a Phillips Mosaic small animal PET scanner was performed 3 h p.i. for all three tracers. Mice injected with [124I]IAZA were scanned again after 24 h and 48 h. In addition to the mice breathing air, in the case of [18F]FAZA and [124I]IAZA a second group of mice for each tracer was kept in an atmosphere of carbogen gas (5% of CO2 + 95 % of O2; from 1 h before to 3 h after injection) to evaluate the oxygenation dependency on uptake (all experiments n = 4). After the final PET scan animals were sacrificed and biodistribution was studied. RESULTS: Mice injected with [18F]FAZA displayed significantly higher tumor-to background (T/B) ratios (5.19 +/- 0.73) compared to those injected with [18F]FMISO (3.98 +/- 0.66; P $lt; 0.05) or [124I]IAZA (2.06 +/- 0.26; P $lt; 0.001) 3 h p.i. Carbogen breathing mice showed lower ratios ([18F]FAZA: 4.06 +/- 0.59; [124I]IAZA: 2.02 +/- 0.36). The T/B ratios increased for [124I]IAZA with time (24 h: 3.83 +/- 0.61; 48 h: 4.20 +/- 0.80), but after these late time points the absolute whole body activity was very low, as could be seen from the biodistribution data (< 0.1 %ID/g for each investigated organ) and ratios were still lower than for [18F]FAZA 3 h p.i. Due to de-iodination uptake in thyroid was high. Biodistribution data were in good agreement with the PET results. CONCLUSIONS: [18F]FAZA showed superior biokinetics compared to [18F]FMISO and [124I]IAZA in this study. Imaging at later time points that are not possible with the short lived 18F labeled tracers resulted in no advantage for [124I]IAZA, i. e. tumor to normal tissue ratios could not be improved.

InterPro, progress and status in 2005.

InterPro, an integrated documentation resource of protein families, domains and functional sites, was created to integrate the major protein signature databases. Currently, it includes PROSITE, Pfam, PRINTS, ProDom, SMART, TIGRFAMs, PIRSF and SUPERFAMILY. Signatures are manually integrated into InterPro entries that are curated to provide biological and functional information. Annotation is provided in an abstract, Gene Ontology mapping and links to specialized databases. New features of InterPro include extended protein match views, taxonomic range information and protein 3D structure data. One of the new match views is the InterPro Domain Architecture view, which shows the domain composition of protein matches. Two new entry types were introduced to better describe InterPro entries: these are active site and binding site. PIRSF and the structure-based SUPERFAMILY are the latest member databases to join InterPro, and CATH and PANTHER are soon to be integrated. InterPro release 8.0 contains 11 007 entries, representing 2573 domains, 8166 families, 201 repeats, 26 active sites, 21 binding sites and 20 post-translational modification sites. InterPro covers over 78% of all proteins in the Swiss-Prot and TrEMBL components of UniProt. The database is available for text- and sequence-based searches via a webserver (http://www.ebi.ac.uk/interpro), and for download by anonymous FTP (ftp://ftp.ebi.ac.uk/pub/databases/interpro).