Gastrin and cholecystokinin peptide-based radiopharmaceuticals: an in vivo and in vitro comparison

The development of suitable radioligands for targeting CCK-2 receptor expressing tumors, such as medullary thyroid carcinoma, is of great clinical interest. In the search for the best CCK-2R binding peptides, we have synthesized, evaluated and compared the CCK8 peptide (Asp-Tyr-Met-Gly-Trp-Met-Asp-PheNH(2) ) and two gastrin analogs commonly referred to as MG0 (DGlu-Glu(5)-Ala-Tyr-Gly-Trp-Met-Asp-PheNH(2) ) and MG11 (DGlu(1)-Ala-Tyr-Gly-Trp-Met-Asp-PheNH(2) ). The N-terminal portion of the three peptide sequences was derivatized by introducing the DTPAGlu or DOTA chelators to allow radiolobeling with (111) In(III) and (68) Ga(III), respectively. Saturation binding and cellular internalization experiments were performed on A431 cells overexpressing CCK2R (A431-CCK2R). All compounds showed Kd values in the nM range and were internalized with similar rates in CCK2 receptor overexpressing cells. Biodistribution experiments showed higher specific uptake of both MG0-based compounds compared to conjugates containing the CCK8 and MG11 peptide sequences. The higher retention levels of MG0-based peptides were associated with markedly elevated and undesired kidney uptake compared to the other compounds. Current indications suggest that the 5 Glu N-terminal residues while improving peptide stability and receptor-mediated tumor uptake cause unacceptably high kidney retention. Although displaying lower absolute tumor uptake values, the DOTA-coupled CCK8 peptide provided the best tumor to kidney uptake ratio and appears more suitable as lead compound for improvement of radiopharmaceutical properties

Biophysical and biochemical characterization of a liposarcoma-derived recombinant MnSOD protein acting as an anticancer agent

A recombinant MnSOD (rMnSOD) synthesized by specific cDNA clones derived from a liposarcoma cell line was shown to have the same sequence as the wild-type MnSOD expressed in the human myeloid leukaemia cell line U937, except for the presence of the leader peptide at the N-terminus. These results were fully confirmed by the molecular mass of rMnSOD as evaluated by ES/MS analysis (26662.7 Da) and the nucleotide sequence of the MnSOD cDNA. The role of the leader peptide in rMnSOD was investigated using a fluorescent and/or 68Gallium-labelled synthetic peptide. The labelled peptide permeated MCF-7 cells and uptake could be inhibited in the presence of an excess of oestrogen. In vivo it was taken up by the tumour, suggesting that the molecule can be used for both therapy and diagnosis. The in vitro and in vivo pharmacology tests confirmed that rMnSOD is only oncotoxic for tumour cells expressing oestrogen receptors. Pharmacokinetic studies in animals performed with 125I- and 131I-labelled proteins confirmed that, when administered systemically, rMnSOD selectively reached the tumour, where its presence was unambiguously demonstrated by scintigraphic and PET scans. PCR analysis revealed that Bax gene expression was increased and the Bcl2 gene was down regulated in MCF7 cells treated with rMnSOD, which suggests that the protein induces a pro-apoptotic mechanism

The [Tc(N)(PNP)]2+ metal fragment labeled cholecystokinin-8 (CCK8) peptide for CCK-2 receptors imaging: in vitroand in vivo studies

The radiolabeling of the natural octapeptide CCK8, derivatized with a cysteine residue (Cys-Gly-CCK8), by using the metal fragment [99mTc(N)(PNP3)]2+ (PNP3 = N,N-bis(dimethoxypropylphosphinoethyl)methoxyethylamine) is reported. The [99mTc(N)(NS-Cys-Gly-CCK8)(PNP3)]+ complex was obtained according to two methods (one-step or two-step procedure) that gave the desired compound in high yield. The complex is stable in aqueous solution and in phosphate buffer. In vitro challenge experiments with an excess of cysteine and glutathione indicate that no transchelation reactions occur, confirming the high thermodynamic stability and kinetic inertness of this compound. Stability studies carried out in human and mouse serum, as well as in mouse liver homogenates, show that the radiolabeled compound remains intact for prolonged incubation at 37 degrees C. Binding properties give Kd (19.0 +/- 4.6 nmol/l) and Bmax (approximately 10(6) sites/cell) values in A431 cells overexpressing the CCK2-R. In vivo evaluation of the compound shows rapid and specific targeting to CCK2-R, a fourfold higher accumulation compared to nonreceptor expressing tumors

A study of gas contaminants and interaction with materials in RPC closed loop systems

Resistive Plate Counters (RPC) detectors at the Large Hadron Collider (LHC) experiments use gas recirculation systems to cope with large gas mixture volumes and costs. In this paper a long-term systematic study about gas purifiers, gas contaminants and detector performance is discussed. The study aims at measuring the lifetime of purifiers with unused and used cartridge material along with contaminants release in the gas system. During the data-taking the response of several RPC double-gap detectors was monitored in order to characterize the correlation between dark currents, filter status and gas contaminants

Bombesin peptide antagonist for target-selective delivery of liposomal doxorubicin on cancer cells

Purpose: This study addresses novel peptide modified liposomal doxorubicin to specifically target tissues overexpressing bombesin (BN) receptors. Methods: DOTA-(AEEA)2-peptides containing the [7–14]bombesin and the new BN-AA1 sequence have been synthesized to compare their binding properties and in serum stabilities. The amphiphilic peptide derivative (MonYBN- AA1) containing BN-AA1, a hydrophobic moiety, polyethylenglycole (PEG), and diethylenetriaminepentaacetate (DTPA), has been synthesized. Liposomes have been obtained by mixing of MonY-BN-AA1 with 1,2-distearoylsn-glycero-3-phosphocholine (DSPC). Results: Both 111In labeled peptide derivatives present nanomolar Kd to PC-3 cells. 177Lu labeled peptide DOTA- (AEEA)2-BN-AA1 is very stable (half-life 414.1 h), while DOTA-(AEEA)2-BN, shows a half-life of 15.5 h. In vivo studies on the therapeutic efficacy of DSPC/MonY-BN-AA1/Dox in comparison to DSPC/MonY-BN/Dox, were performed in PC-3 xenograft bearing mice. Both formulations showed similar tumor growth inhibition (TGI) compared to control animals treated with non-targeted DSPC/Dox liposomes or saline solution. For DSPC/MonY-BN-AA1/Dox the maximum effect was observed 19 days after treatment. Conclusions: DSPC/MonY-BN-AA1/Dox nanovectors confirm the ability to selectively target and provide therapeutic efficacy in mice. The lack of receptor activation and possible acute biological side effects provided by using the AA1 antagonist bombesin sequence should provide safe working conditions for further development of this class of drug delivery vehicles

Biopsy confirmation of metastatic sites in breast cancer patients:clinical impact and future perspectives

Determination of hormone receptor (estrogen receptor and progesterone receptor) and human epidermal growth factor receptor 2 status in the primary tumor is clinically relevant to define breast cancer subtypes, clinical outcome,and the choice of therapy. Retrospective and prospective studies suggest that there is substantial discordance in receptor status between primary and recurrent breast cancer. Despite this evidence and current recommendations,the acquisition of tissue from metastatic deposits is not routine practice. As a consequence, therapeutic decisions for treatment in the metastatic setting are based on the features of the primary tumor. Reasons for this attitude include the invasiveness of the procedure and the unreliable outcome of biopsy, in particular for biopsies of lesions at complex visceral sites. Improvements in interventional radiology techniques mean that most metastatic sites are now accessible by minimally invasive methods, including surgery. In our opinion, since biopsies are diagnostic and changes in biological features between the primary and secondary tumors can occur, the routine biopsy of metastatic disease needs to be performed. In this review, we discuss the rationale for biopsy of suspected breast cancer metastases, review issues and caveats surrounding discordance of biomarker status between primary and metastatic tumors, and provide insights for deciding when to perform biopsy of suspected metastases and which one (s) to biopsy. We also speculate on the future translational implications for biopsy of suspected metastatic lesions in the context of clinical trials and the establishment of bio-banks of biopsy material taken from metastatic sites. We believe that such bio-banks will be important for exploring mechanisms of metastasis. In the future,advances in targeted therapy will depend on the availability of metastatic tissue

Assessment Protocol for Cognitive and Auditory Processing Skills for Clients Receiving Neurofeedback Treatment for Traumatic Brain Injury & Concussion: Literature Review

Neurofeedback has become increasingly popular in the medical world and will hopefully become more commonly used in the fields of speech-language pathology and audiology. Currently, there is a lack of a singular, baseline and progression diagnostic tool to measure a client’s cognitive and auditory processing skills once they are referred for neurofeedback treatment

Retrofit assessment of masonry buildings through simplified structural analysis

The current seismic prevention strategy is based on a unitary approach aimed at a risk mitigation, also at territorial level. The Italian guidelines for the assessment and mitigation of seismic risk of cultural heritage provides indications for the seismic analysis of protected cultural heritage, with the aim of specifying a path of knowledge, assessing the level of safety and planning possible improvements. The Italian building heritage is very vast and heterogeneous and was devastated by earthquakes due to its high vulnerability; therefore, the seismic risk mitigation also requires the availability of simple and handy analysis tools. The aim of this paper is the illustration of an easy, although approximate, procedure for the evaluation of the seismic safety index and the optimization of strengthening interventions. The procedure is applied to buildings located in the province of Caserta. The analyses are performed with reference to two types of buildings that are particularly recurrent and representative of the building heritage of this area and placed in areas with different seismic hazard

Evaluating the Effect of a Self-Healing Elastomer on the Self-Healing Properties of Asphalt Cement

Asphalt pavements exhibit an interesting behaviour when the traffic loading is removed. The chemical structure of asphalt cement lends itself to the ability to heal damage and improve the longevity of the pavement. This phenomenon was first discovered in the 1960s and makes up an interesting area of research. The area of self-healing materials has been a growing area of research for materials in general, but recently attempts have been made to improve the natural healing capabilities of asphalt cement. Other branches of science have begun using microcapsules dispersed through the matrix to distribute healing agent upon damage. Styrene Butadiene Styrene (SBS) modification of asphalt cement is already a common technology in the pavement industry, and this has inspired the idea to introduce a polymer that has self-healing properties into asphalt cement. This thesis looks at the effect of traditional elastomeric modification on the healing efficiency of asphalt cement and explore the use of a novel self-healing elastomer (SHE) to modify the asphalt cement healing properties. Data in this thesis indicates that the self-healing elastomer used here was unable to improve the healing efficiency of asphalt cement, while SBS has shown some ability to improve crack healing. SBS has also shown a great ability to improve adhesion, which may influence the cohesive healing ability of asphalt cement