Publications by authors named "Simecek J"

The cellular adhesion receptor αvβ6-integrin is highly expressed in many cancers, e.g., pancreatic, lung, head-and-neck, cervical, bladder, and esophageal carcinoma.

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Introduction: Since the start of the Russo-Ukrainian war, most reports have focused on trauma and combat conditions. Trauma care is essential; however, disease and nonbattle injuries (DNBIs) also burden armies and reduce combat effectiveness. Dental emergencies (DEs) account for a substantial portion of DNBI, but there is limited information on Ukrainian military dental readiness.

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In a recent paper in this journal (, 2023, , 2429), we described an unusually strong impact of regiospecific exchange of phenylalanines by tyrosines in 10 gallium-68-labeled trimers of certain cyclic RGD peptides, c[XRGDLAXp(Me)K] (X = F or Y), on non-specific organ uptakes. We found that there was, in part, no correlation of liver uptake with established polarity proxies, such as the octanol-water distribution coefficient (log ). Since this observation could not be explained straightforwardly, we suggested that the symmetry of the compounds had resulted in a synergistic interaction of certain components of the macromolecules.

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Purpose: αvβ6 integrin is exclusively expressed in epithelial cells and is upregulated in many carcinomas, such as pancreatic ductal adenocarcinomas (PDACs) and head and neck squamous cell carcinomas (H&NSCCs). Trivehexin is a recently synthesized trimerized αvβ6 integrin selective nonapeptide, which can be labeled with a positron emitter like 68 Ga. This is a pilot study to assess the potential role of 68 Ga-Trivehexin PET/CT in patients with H&NSCC and PDAC and their correlation with αvβ6 integrin expression by the tumor tissue on immunohistochemistry (IHC).

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Purpose: Ga-Trivehexin is an investigational PET radiopharmaceutical (NCT05799274) targeting αvβ6-integrin for PET imaging of carcinomas. Lu-D0301 is a structurally related therapeutic peptide tetramer. However, it showed considerable kidney uptake in rodents, impeding clinical applicability.

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Introduction: Information from published studies describing dental treatment of nonmilitary personnel in a military theater of operations is sparse. The primary objective of this study is to determine the number of dental emergencies (DEs) and the types of dental treatment rendered on non-U.S.

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Article Synopsis
  • A literature review examined 14 studies on the frequency of medical evacuations (MEDEVAC) for dental emergencies (DE) and oral-maxillofacial (OMF) injuries in both military and civilian contexts.
  • Among military personnel from 1982 to 2013, DE/OMF issues constituted 2-16% of all medical evacuations, while civilian evacuations in oil and gas industries showed a range of 5.3-14.6% due to dental problems, with wilderness expeditions indicating DEs as a common injury type.
  • The review highlights that dental and OMF issues are significant reasons for evacuations but emphasizes the need for further research to assess their impact on healthcare costs due to the limited
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Purpose: Ac-225 labeled with prostate-specific membrane antigen (PSMA-617), a transmembrane glycoprotein which is highly expressed in prostate carcinoma cells, is presently being considered a promising agent of targeted alpha therapy for the treatment of patients suffering from metastatic castration-resistant prostate cancer. In the present study, we report an optimized protocol for the preparation of therapeutic dose of Ac-225 PSMA-617 with high yield and radiochemical purity (RCP).

Methods: Ac-225 PSMA-617 was prepared by adding the peptidic precursor-PSMA-617 (molar ratios, Ac-225: PSMA-617 = 30:1) in 1 ml ascorbate buffer to Ac-225 and heating the reaction mixture at 90°C for 25 min to obtain the radiopeptide with high RCP and yield.

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Because of the excellent ability of α-particles to transfer a high amount of energy over a short tissue range, targeted α-therapy has been attracting rising numbers of nuclear medicine centers. In this study, we estimated the radiation exposure to the occupational workers with pocket dosimeters during handling of the α-emitter Bi, used for targeted α-therapy of neuroendocrine tumor and castration-resistant prostate cancer patients. The dose rates from patients at different distances and time points after injection of the therapy were also evaluated.

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Here, we report on the outcome of the 2nd International Danube Symposium on advanced biomarker development that was held in Vienna, Austria, in early 2018. During the meeting, cross-speciality participants assessed critical aspects of non-invasive, quantitative biomarker development in view of the need to expand our understanding of disease mechanisms and the definition of appropriate strategies both for molecular diagnostics and personalised therapies. More specifically, panelists addressed the main topics, including the current status of disease characterisation by means of non-invasive imaging, histopathology and liquid biopsies as well as strategies of gaining new understanding of disease formation, modulation and plasticity to large-scale molecular imaging as well as integrative multi-platform approaches.

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Article Synopsis
  • There is a significant occurrence of dental emergencies (about 15% annually) among military personnel, highlighting the importance of Dental Readiness as part of their overall medical preparedness.
  • The study reviewed data from 1955 to 2017, analyzing the incidence of dental emergencies and cranio-oral-maxillofacial injuries in deployed US military personnel.
  • Results showed annual dental emergency rates varied widely, with a notable mean rate of 118.2 per 1,000 personnel per year in recent years, while the incidence of maxillofacial injuries stood at around 3.0 per 1,000. *
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Introduction: Computer-aided design/computer-aided manufacturing (CAD/CAM) has gained increasing popularity since the first commercially viable dental system was introduced in the mid-1980s. Digitally milled dental restorations can be fabricated chairside in the course of one dental appointment, reducing time, cost, and manpower when compared with traditional laboratory-fabricated analog restorations. Clinical performance, physical properties, and esthetics of digital restorations have been shown to be comparable to traditional analog restorations.

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Background: The recently growing interest in targeted alpha-therapy (TAT) calls for improvement of the labelling chemistry of the corresponding radionuclides. Bi is a short-lived alpha emitter which emits only one alpha particle in its decay chain. Hence, it might be safer in application than other respective nuclides, such as Ra or Ac, because no alpha-emitting daughters are released upon recoil.

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Background: Few studies have examined the causes or mechanisms of oral-maxillofacial (OMF) injury among deployed military populations. This study reports causes of OMF injuries to U.S.

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Background: Cranial and oral-maxillofacial injuries accounted for 33% of military visits to in-theater (Level III) military treatment facilities for battle injuries during Operation Enduring Freedom (OEF) and Operation Iraqi Freedom (OIF). Even after years of conflict, the size and scope of oral-maxillofacial injuries in military armed conflict is still not fully understood. This study reports U.

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In order to compare the coordination properties of 1,4,7-triazacyclononane (tacn) derivatives bearing varying numbers of phosphinic/carboxylic acid pendant groups towards 68Ga, 1,4,7-triazacyclononane-7-acetic-1,4-bis(methylenephosphinic) acid (NOPA) and 1,4,7- triazacyclononane-4,7-diacetic-1-[methylene(2-carboxyethyl)phosphinic] acid (NO2AP) were synthesized using Mannich reactions with trivalent or pentavalent forms of H-phosphinic acids as phosphorus components. Stepwise protonation constants logK1-3 12.06, 3.

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Background: Due to its high expression in prostate cancer, PSMA (prostate-specific membrane antigen) represents an ideal target for both diagnostic imaging and endoradiotherapeutic approaches. Based on a previously published highly specific PSMA ligand ([(68)Ga]DOTA-FFK(Sub-KuE)), we developed a corresponding metabolically stable 1,4,7,10-tetraazacyclododececane,1-(glutaric acid)-4,7,10-triacetic acid (DOTAGA) construct for theranostic treatment of prostate cancer.

Methods: All ligands were synthesized by a combined solid phase and solution phase synthesis strategy.

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Unlabelled: On the basis of the high and consistent expression of prostate-specific membrane antigen (PSMA) in metastatic prostate cancer (PC), the goal of this study was the development, preclinical evaluation, and first proof-of-concept investigation of a PSMA inhibitor for imaging and therapy (PSMA I&T) for (68)Ga-based PET and (177)Lu-based endoradiotherapeutic treatment in patients with metastatic and castration-resistant disease.

Methods: PSMA I&T was synthesized in a combined solid phase and solution chemistry strategy. The PSMA affinity of (nat)Ga-/(nat)Lu-PSMA I&T was determined in a competitive binding assay using LNCaP cells.

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In the past few years, gallium-68 has demonstrated significant potential as a radioisotope for positron emission tomography (PET), and the optimization of chelators for gallium coordination is a major goal in the development of radiopharmaceuticals. Methylaminotriazacyclononane trimethylphosphinate (MA-NOTMP), a new C-functionalized triazacyclononane derivative with phosphinate pendant arms, presents excellent coordination properties for (68) Ga (low ligand concentration, labelling at low pH even at room temperature). A "ready-to-be-grafted" bifunctional chelating agent (p-NCS-Bz-MA-NOTMP) was prepared to allow (68) Ga labelling of sensitive biological vectors.

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Objectives: The objectives of this study were to (1) quantify the number of intratheater dental Medical evacuations (MEDEVACs) required for French Soldiers in Mali during Operation Serval and (2) determine a Soldier's time away from their unit because of MEDEVAC, dental treatment, and return to unit.

Methods: Data concerning MEDEVACs occurring during Operation Serval were recorded by the Patient Evacuation Coordination Center. MEDEVACs resulting from oral/facial/dental conditions were evaluated for the period from February 15, 2013 to May 15, 2013.

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Background: Recently, an intra-patient comparison demonstrated that the somatostatin (sst) ligand [(68)Ga]HA-DOTATATE ([(68)Ga]DOTA-3-iodo-Tyr(3)-octreotate) provides PET images comparable to or superior to those obtained with [(68)Ga]DOTATATE. To provide a comprehensive basis for nevertheless observed slight differences in tracer biodistribution and dosimetry, the characteristics of [(68)Ga]HA-DOTATATE were investigated in a detailed preclinical study.

Methods: Affinities of (nat)Ga-HA-DOTATATE and (nat)Ga-DOTATATE to sst1-5 were determined using membrane preparations and [(125)I]SST-28 as radioligand.

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Chemokine ligand-receptor interactions play a pivotal role in cell attraction and cellular trafficking, both in normal tissue homeostasis and in disease. In cancer, chemokine receptor-4 (CXCR4) expression is an adverse prognostic factor. Early clinical studies suggest that targeting CXCR4 with suitable high-affinity antagonists might be a novel means for therapy.

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Background: In the past, the U.S. Army Reserve (USAR) and Army National Guard (ARNG) have exhibited lower levels of medical and dental readiness than active duty (AD) Soldiers when activated for deployment.

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