Simple Questionnaires to Improve Pooling Strategies for SARS-CoV-2 Laboratory Testing

Background: Liberal PCR testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is key to contain the coronavirus disease 2019 (COVID-19) pandemic. Combined multi-sample testing in pools instead of single tests might enhance laboratory capacity and reduce costs, especially in low- and middle-income countries. Objective: The purpose of our study was to assess the value of a simple questionnaire to guide and further improve pooling strategies for SARS-CoV-2 laboratory testing. Methods: Pharyngeal swabs for SARS-CoV-2 testing were obtained from healthcare and police staff, hospital inpatients, and nursing home residents in the southwestern part of Germany. We designed a simple questionnaire, which included questions pertaining to a suggestive clinical symptomatology, recent travel history, and contact with confirmed cases to stratify an individual’s pre-test probability of having contracted COVID-19. The questionnaire was adapted repeatedly in face of the unfolding pandemic in response to the evolving epidemiology and observed clinical symptomatology. Based on the response patterns, samples were either tested individually or in multi-sample pools. We compared the pool positivity rate and the number of total PCR tests required to obtain individual results between this questionnaire-based pooling strategy and randomly assembled pools. Findings: Between March 11 and July 5, 2020, we processed 25,978 samples using random pooling (n = 6,012; 23.1%) or questionnaire-based pooling (n = 19,966; 76.9%). The overall prevalence of SARS-CoV-2 was 0.9% (n = 238). Pool positivity (14.6% vs. 1.2%) and individual SARS-CoV-2 prevalence (3.4% vs. 0.1%) were higher in the random pooling group than in the questionnaire group. The average number of PCR tests needed to obtain the individual result for one participant was 0.27 tests in the random pooling group, as compared to 0.09 in the questionnaire-based pooling group, leading to a laboratory capacity increase of 73% and 91%, respectively, as compared to single PCR testing. Conclusions: Strategies that combine pool testing with a questionnaire-based risk stratification can increase laboratory testing capacities for COVID-19 and might be important tools, particularly in resource-constrained settings

Radiopeptidtherapie des Ovarialkarzinoms mit Alphastrahlern: Verbesserte Tumorkontrolle durch Kombination von 213Bi-DTPA-F3 mit Taxol bei irreversiblen Zellzyklusarrest von Ovarialkarzinomzellen in der G2/M-Phase

Ziel: Konjugate des Tumor-homing Peptids F3 mit Alpha-Emittern (213Bi-DTPA-F3) sind in der Behandlung der Peritonealkarzinose in präklinischen Modellen des Ovarialkarzinoms wirksam. Von uns wurde untersucht, ob die Tumorkontrolle durch Kombination mit Taxol verbessert werden kann und welche molekularen Mechanismen einer Wirkungsverstärkung zugrunde liegen. Methoden: 1 x 107 OVCAR3-luc Zellen wurden i.p. in SCID Mäuse injiziert, um Xenograft-Tumore zu erhalten. Therapiebeginn 10 Tage nach Tumorinokulation: A) Kontrollgruppe: 12 i.p. Injektionen mit 100 µl PBS. B) Taxol Monotherapie: 6 i.p. Injektionen mit 300 µg Taxol. C) 213Bi-DTPA-F3 Monotherapie: 6 Injektionen mit 50 µCi 213Bi-DTPA-F3 in zweitägigen Abständen. D) Kombinationstherapie: im täglichen Wechsel je 6 Injektionen 300µg Taxol oder µCi 213Bi-DTPA-F3. Die Therapiekontrolle erfolgte mit optischer Bildgebung und pathologischer Bestimmung der Tumorlast. Zur Bestimmung der anti-Tumor-Aktivität wurden Alamar Blue®- und Kolonie-Bildungs-Assays durchgeführt. Der Zellzyklus wurde flow-zytometrisch quantifiziert. Die Aktivität der Caspase 3 und p21WAF1 wurden im Western-Blot untersucht. Resultate: Die Überlebenszeit in der Kontrollgruppe betrug im Mittel 37 ± 5,9 Tage [25;48], in der Taxol-Gruppe 41,5 ± 8,6 [24; 58], nach 213Bi-DTPA-F3 Therapie 84 ± 1,3 und nach Kombinatinstherapie mit Taxol und 213Bi-DTPA-F3 119,3 ± 13 Tage [56;141]. Die Optische Luminiszenz-Bildgebung zeigte ein deutliches Therapieansprechen in allen Therapiegruppen, am deutlichsten nach Kombinationstherapie. Das optische Signal korrelierte mit der histopathologischen Tumorlast. Kolonie-Bildungs-Assays zeigten, dass die ID50 des 213Bi-DTPA-F3 bei 5 µCi/ml liegt. Durch die Kombinationsbehandlung mit Taxol wurde die Wirkung verstärkt (ID50 auf 2,5 µCi/ml). Im Alamar Blue Assay wurde der Effekt der Kombinationstherapie auf die Zellproliferation untersucht. Sowohl 213Bi-DTPA-F3 als auch Taxol hemmten die Proliferation von OVCAR3-Zellen, am effektivsten war jedoch die Kombinationstherapie. Western-Blots zeigten, dass durch jede der drei Therapien Caspase 3 aktiviert wird; die Caspase-Aktivität wird jedoch durch die Kombinationstherapie nicht weiter verstärkt. In der Zellzyklusanalyse zeigte sich, dass die Zellen in der G2/M-Phase akkumulieren. Nach Monotherapie, nicht jedoch in der Kombinationstherapie nimmt jedoch die Zahl der in der G2/M-Phase arretierten Zellen nach 48 Stunden wieder ab. Parallel kommt nur in der Kombinationstherapie zu vermehrter Expression von p21WAF1 einem Molekül, das Zellzyklusarrest induziert. Schlussfolgerungen: Taxol verstärkt die Wirkung von 213Bi-DTPA-F3 durch eine irreversible p21WAF1 bedingte Blockade des Zellzyklus in der G2/M-Phase und daraus resultierende Hemmung der Proliferation. In zukünftigen klinischen Studien sollte die Kombination von Alpha-Strahlern mit Taxol getestet werden.JRC.E.5-Nuclear chemistr

Somatostatin receptor based PET/CT in patients with the suspicion of cardiac sarcoidosis: an initial comparison to cardiac MRI

Diagnosis of cardiac sarcoidosis is often challenging. Whereas cardiac magnetic resonance imaging (CMR) and positron emission tomography/computed tomography (PET/CT) with $^{18}$F-fluorodeoxyglucose (FDG) are most commonly used to evaluate patients, PET/CT using radiolabeled somatostatin receptor (SSTR) ligands for visualization of inflammation might represent a more specific alternative. This study aimed to investigate the feasibility of SSTR–PET/CT for detecting cardiac sarcoidosis in comparison to CMR. 15 patients (6 males, 9 females) with sarcoidosis and suspicion on cardiac involvement underwent SSTR-PET/CT imaging and CMR. Images were visually scored. The AHA 17-segment model of the left myocardium was used for localization and comparison of inflamed myocardium for both imaging modalities. In semi-quantitative analysis, mean (SUV$_{mean}$) and maximum standardized uptake values (SUV$_{max}$) of affected myocardium were calculated and compared with both remote myocardium and left ventricular (LV) cavity. SSTR-PET was positive in 7/15, CMR in 10/15 patients. Of the 3 CMR+/PET- subjects, one patient with minor involvement (<25% of wall thickness in CMR) was missed by PET. The remaining two CMR+/PET- patients displayed no adverse cardiac events during follow-up. In the 17-segment model, PET/CT yielded 27 and CMR 29 positive segments. Overall concordance of the 2 modalities was 96.1% (245/255 segments analyzed). SUV$_{mean}$ and SUV$_{max}$ in inflamed areas were 2.0±1.2 and 2.6±1.2, respectively. The lesion-to-remote myocardium and lesion-to-LV cavity ratios were 1.8±0.2 and 1.9±0.2 for SUV$_{mean}$ and 2.0±0.3 and 1.7±0.3 for SUV$_{max}$, respectively. Detection of cardiac sarcoidosis by SSTR-PET/CT is feasible. Our data warrant further analysis in larger prospective series

Combined 213Bi-DTPA- F3 and paclitaxel treatment of peritoneal spread of human ovarian carcinoma in a mouse model enhances therapeutic efficacy due to enhanced induction of apoptosis and G2/M phase cell-cycle arrest

Aim: High cytotoxicity of α-emitters is due to a high linear energy transfer resulting in induction of lethal DNA double-strand breaks. Therefore, targeted therapy with alpha-particle emitting radionuclides is a promising option in treatment of peritoneal carcinomatosis. Stable conjugates of the vascular tumor-homing peptide F3 with the α-emitter 213Bi specifically target nucleolin on the surface of proliferating tumor cells. In proliferating cells, nucleolin cycles between the cell surface and the nucleus. The aim of our study was to determine efficacy of combined 213Bi-DTPA-F3 and paclitaxel treatment compared to treatment with either 213Bi-DTPA-F3 or paclitaxel both in vitro and in vivo. Materials and methods: Effects on OVCAR3 ovarian carcinoma cells of treatment with 213Bi-DTPA-F3 and paclitaxel, alone or in combination, respectively, were assayed in terms of cell viability (alamarBlue assay), cell survival (clonogenic assay), cell-cycle arrest and the mode of cell death (flow cytometric analyses). For analysis of therapeutic efficacy SCID mice were injected intraperitoneally with OVCAR3 cells (1x107). Starting at day 10 after tumor cell inoculation animals were treated intraperitoneally six times at intervals of two or three days with PBS (control; n=12), paclitaxel (120 μg; n=6), 213Bi-DTPA-F3 (1.85 MBq; n=6) or combinded paclitaxel and 213Bi-DTPA-F3 (120 μg, 1.85 MBq; n=6). Therapeutic efficacy of the different treatment regimens was monitored non-invasively by bioluminescence imaging and registration of overall survival in combination with histopathologic analyses. Results: Treatment of OVCAR-3 cells in vitro with combined 213Bi-DTPA-F3 and paclitaxel was superior to treatment with either 213Bi-DTPA-F3 or paclitaxel in terms of reduction of cell viability, reduction of cell survival, induction of apoptosis and arrest of cells in G2/M phase. Accordingly, treatment of i.p. xenograft OVCAR-3 tumors was most efficient using combined 213Bi-DTPA-F3 (1.85 MBq) and paclitaxel (120 μg) as demonstrated by non-invasive bioluminescence imaging at different time points after tumor cell inoculation and histophatologic investigation of tumor spread on mesentery of the small and large intestine. Moreover, mean survival of xenograft mice that received combined 213Bi-DTPA-F3 and paclitaxel therapy (119 ± 13 days) was significantly superior to mice treated with either 213Bi-DTPA-F3 (84 ± 1 days) or paclitaxel (42 ± 9 days) or to controls treated with PBS (37 ± 6 days). Conclusion: Combined treatment with 213Bi-DTPA-F3 and paclitaxel significantly increased mean survival of mice with peritoneal carcinomatosis of ovarian origin compared to treatment with either 213Bi-DTPA-F3 or paclitaxel thus favouring future therapeutic application of a combined treatment regimen.JRC.E.5-Nuclear chemistr

Die Alpha-Emitter Radioimmuntherapie des multiplen Myeloms mit 213Bi-CHX-A“-DTPA-anti-CD38 Immunkonjugaten zeigt eine hohe Effizienz im präklinischen Xenograft-Modell

Trotz jüngster Fortschritte in der Behandlung des multiplen Myeloms mit Bortezomib oder Lenalidomid ist diese Tumorerkrankung unheilbar. Ein Zielmolekül für einen neuen Therapieansatz ist das Glykoprotein CD38, das von Myelomzellen meist überexprimiert wird. Es wurden die therapeutische Effizienz von 213Bi-anti-CD38 Immunkonjugaten im Mausmodell und die zugrundeliegenden molekularen Mechanismen untersucht.JRC.E.5-Nuclear chemistr

PIGS or Lambs? The European Sovereign Debt Crisis and the Role of Rating Agencies

Rating agencies, Sovereign debt, Credit risk, Eurozone, Panel data, Debt crisis, G24, H63, F34,