10 results on '"Zimmermanns, B"'
Search Results
2. Exhalation of 131I after radioiodine therapy: Dosimetric considerations based on measurements in exhaled air
- Author
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Sudbrock, F., Fischer, Th., Zimmermanns, B., Drzezga, A., and Schomäcker, K.
- Published
- 2017
- Full Text
- View/download PDF
3. Retention efficacy and release of radioiodine in fume hoods
- Author
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Schomäcker, K., Fischer, T., Zimmermanns, B., Bregulla, J., Sudbrock, F., Prante, O., and Drzezga, A.
- Published
- 2017
- Full Text
- View/download PDF
4. Exhalation of I-131 after radioiodine therapy: Dosimetric considerations based on measurements in exhaled air
- Author
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Sudbrock, F., Fischer, Th., Zimmermanns, B., Drzezga, A., Schomaecker, K., Sudbrock, F., Fischer, Th., Zimmermanns, B., Drzezga, A., and Schomaecker, K.
- Abstract
It is well known that a considerable amount of radioiodine is exhaled after radioiodine therapy (RIT) leading to unwanted radiation exposure through inhalation for non-involved persons. This study focuses on the amount of exhalation in the breath-out air of RIT-patients and the dosimetric consequences. Furthermore, the correlation between radioiodine uptake and exhalation was investigated. The radioiodine species were collected in a filter system and quantified over time by measurements with a scintillation counter. The dosimetric implications were then studied for different exposure scenarios. Of the activity administered to the patient, approximately 10(-3)% (50-110 ppm) is exhaled. The radioiodine inhalation taking place following exhalation in the vicinity yields doses of up to 500 mu Sv (children, staying with the patient immediately after application and for the next 8 h). Three days after administration the doses are significantly reduced. This study lays emphasis on previous assumptions that exhalation depends on thyroid storage. Regardless of the type of thyroid disease, the predominant form exhaled is organic radioiodine. The amount of exhaled radioiodine is small but from the point of view of radiation protection, by no means negligible immediately after administration. Radiation doses received by incqrporation of exhaled radioiodine can easily exceed 100 mu Sv soon after administration of radioiodine. Three days after RIT the radioactivity can still be measured in the exhaled air but even at maximum, the annual doses lie far below 10 mu Sv and are thus comparatively low. (C) 2016 Elsevier Ltd. All rights reserved.
- Published
- 2017
5. Retention efficacy and release of radioiodine in fume hoods
- Author
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Schomaecker, K., Fischer, T., Zimmermanns, B., Bregulla, J., Sudbrock, F., Prante, O., Drzezga, A., Schomaecker, K., Fischer, T., Zimmermanns, B., Bregulla, J., Sudbrock, F., Prante, O., and Drzezga, A.
- Abstract
Procedures to determine the release of hazardous gaseous substances including radioactive iodine are covered by different norms such as the European standard EN 14175 and the German national standard DIN 25466. The detection of sulphur hexafluoride (SF6) is required to comply with the prescribed methodology. The detection limit of this test is 4.5.10(-7) mol/m(3) in exhaust air. This detection limit would represent a very high activity in the region of 0.27 TBq/m(3) leading to an unacceptable risk. We therefore developed a test using a filter system, consisting of a combination of filters capable of separating various chemical forms of airborne radioiodine. Air samples were collected directly in front of the fume hood and in the laboratory beside two different fume hoods of a similar construction with a final activated carbon filter for retention of radioiodine. Particular attention was therefore paid to air samples taken after passage over the filters. Significant differences in the degree of retention of iodine were found between the two fume hoods investigated. In one test a malfunction of the fume hood was demonstrated. In this case 0.148 x 10(-3)% of the total released activity per m(3) air was found 1 cm in front of the hood sash. A remarkably high fraction of the activity released in the fume hood (1.3 x 10(-3)%/m(3) air) was measured after the activated carbon filter. In the ambient air, values of up to 8.6 x 10(-6)% pro m(3) laboratory air sampled were measured, despite a 6-8-fold air exchange. The selected procedure is a factor of 10(11) (Schomacker et al., 2001) more sensitive than the standard recommended methods (EN 14175). The standard test prescribed by the DIN/EN failed to reveal any inadequacy in the protective function of the radionuclide hood with respect to radioiodine retention. (C) 2016 Elsevier Ltd. All rights reserved.
- Published
- 2017
6. Tumoricidal Activity and Side Effects of Radiolabeled Anti-NCAM [ 131 I]-Iodine-ERIC1 in Neuroblastoma-Bearing Mice.
- Author
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Fischer T, Dietlein F, Bongartz D, Klehr M, Zimmermanns B, Schmidt M, Mohr A, Mohr F, Sudbrock F, Krapf P, Drzezga A, Dietlein M, and Schomäcker K
- Subjects
- Animals, Mice, Cell Line, Tumor, Neural Cell Adhesion Molecules metabolism, Humans, Mice, SCID, Xenograft Model Antitumor Assays, Immunoconjugates pharmacology, Female, Antibodies, Monoclonal therapeutic use, Antibodies, Monoclonal pharmacology, Neuroblastoma pathology, Neuroblastoma metabolism, Neuroblastoma drug therapy, Iodine Radioisotopes adverse effects
- Abstract
Preliminary studies on a radioactive antibody against the neural cell adhesion molecule (NCAM) demonstrated a significant accumulation of [
131 I]I-ERIC1 in neuroblastoma tumor cells in mice. This study aims to validate the therapeutic efficacy and potential adverse effects of these radioactive immunoconjugates (RICs) in neuroblastoma-bearing mice. To determine the highest tolerated dose, healthy SCID mice received 1 to 22 MBq of [131 I]I-ERIC1, with the survival time measured. Tumor response was evaluated by administering 0.8 to 22 MBq of [131 I]I-ERIC1 to neuroblastoma-bearing mice and assessing tumor size and systemic toxicity through body weight, blood counts, and survival. It was observed that doses up to approximately 3 MBq per animal (150 MBq/kg) were well tolerated, whereas higher doses resulted in systemic toxicity and death. The neuroblastomas exhibited a dose-dependent response, with optimal therapeutic efficacy achieved at 1.8-2.5 MBq per animal (90-125 MBq/kg), significantly extending survival by a factor of five. The antibody ERIC1 is a promising vehicle for the transport of beta emitters into NCAM-positive tumor tissue. An optimal dosage of the [131 I]I-ERIC1 antibody can be established with a balance of tumor-static effects and adverse effects, resulting in a marked extension of survival time.- Published
- 2024
- Full Text
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7. Localization and Tumor Growth Inhibition of I-131-Labeled Monoclonal Antibody ERIC1 in a Subcutaneous Xenograft Model of Small Cell Lung Cancer in SCID Mice.
- Author
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Fischer T, Dietrich C, Dietlein F, Muñoz Vázquez S, Zimmermanns B, Krapf P, Sudbrock F, Drzezga A, Dietlein M, and Schomäcker K
- Subjects
- Animals, Mice, Humans, Cell Line, Tumor, Antibodies, Monoclonal pharmacology, Antibodies, Monoclonal therapeutic use, Female, Tissue Distribution, Small Cell Lung Carcinoma drug therapy, Small Cell Lung Carcinoma pathology, Small Cell Lung Carcinoma metabolism, Xenograft Model Antitumor Assays, Lung Neoplasms drug therapy, Lung Neoplasms pathology, Lung Neoplasms metabolism, Mice, SCID, Iodine Radioisotopes
- Abstract
This study evaluates the efficacy of [
131 I]I-ERIC1 in targeting and inhibiting the growth of SCLC tumors in mice, focusing on tumor accumulation and regression and potential side effects. NCAM-positive NCI-H69 SCLC cells were implanted in CB 17 SCID mice, and [131 I]I-ERIC1 biokinetics were measured in organs and tissues at four post-injection time points (24, 72, 96, and 120 h). The experimental series compared tumor growth, survival, and changes in blood counts among three treatment groups (1, 2, or 3 MBq) and a control group, with treatments initiated either two or five days post implantation. [131 I]I-ERIC1 was synthesized with >95% radiochemical purity and a specific activity of 15 TBq/mmol. Tumor activity peaked at 31.5 ± 6.6% ID/g after four days, demonstrating significant antitumor efficacy, which resulted in sustained remission and extended survival. Hematological toxicity was observed, with the optimal dose identified as 2 MBq per animal administered two days post implantation. [131 I]I-ERIC1 shows promise as a theranostic agent for personalized cancer treatment by effectively targeting SCLC tumors with manageable side effects. However, further studies are required to optimize dosing strategies and minimize toxicity., Competing Interests: The authors declare no conflict of interest.- Published
- 2024
- Full Text
- View/download PDF
8. Myocarditis and pericarditis in association with COVID-19 mRNA-vaccination: cases from a regional pharmacovigilance centre.
- Author
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Istampoulouoglou I, Dimitriou G, Späni S, Christ A, Zimmermanns B, Koechlin S, Stoeckmann O, Winterhalder C, Marono D, Toma V, and Leuppi-Taegtmeyer AB
- Abstract
In this article we summarize suspected adverse events following immunization (AEFI) of pericarditis, myocarditis and perimyocarditis that were reported by our regional pharmacovigilance centre after COVID-19 mRNA-vaccination and discuss their association with these vaccines. Seventeen cases were reported between March and July 2021. Of these, nine had perimyocarditis, five myocarditis and three pericarditis. Twelve patients were male (71%). The median age was 38 years (range 17-88). The most commonly observed presenting symptom was acute chest pain (65%). While 47% of the patients were previously healthy, 53% had at least one pre-existing comorbidity, with hypertension being the most prevalent (24%). The European Society of Cardiology diagnostic criteria for the reported AEFIs were fulfilled in twelve cases (71%). The AEFIs occurred after the first vaccine dose in six cases (35%), after the second vaccine dose in ten cases (59%) and after both doses in one case (6%). The median latency of all AEFIs taken together was 14 days (range 1-28) after the first vaccination and 3 days (range 1-17) after the second one. All patients except one were hospitalized (94%) with a median length of stay of 7.5 days (range 3-13). The majority of patients ( n = 11, 65%) did not experience any complications, and 13 (77%) of the patients had recovered or were recovering at the time of discharge. In 16 of the 17 cases (94%), the association between the AEFI and mRNA-vaccination was considered possible by the pharmacovigilance centre., (Copyright ©2021 The Author(s).)
- Published
- 2021
- Full Text
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9. Cardiovascular adverse effects of lopinavir/ritonavir and hydroxychloroquine in COVID-19 patients: Cases from a single pharmacovigilance centre.
- Author
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Istampoulouoglou I, Zimmermanns B, Grandinetti T, Marzolini C, Harings-Kaim A, Koechlin-Lemke S, Scholz I, Bassetti S, and Leuppi-Taegtmeyer AB
- Abstract
In this article we summarize the cardiovascular adverse events that were observed in three patients during their treatment for COVID-19 and discuss their association with lopinavir/ ritonavir (LPV/r) and hydroxychloroquine (HCQ). The cases were reported to our regional pharmacovigilance centre in April 2020. All three patients were above 75 years in age, male and multimorbid, and had been hospitalized for treatment of COVID-19. As part of their treatment, all of them received a very strictly monitored off-label therapy with LPV/r and HCQ, for which they had given their prior, written, informed consent. In one patient, erythromycin was also administered. All three patients developed a significant QTc time prolongation during or shortly after therapy with the above drugs. On account of this, the treatment had to be discontinued early in each case and QTc time recovered in all three patients., (Copyright ©2021 The Author(s).)
- Published
- 2021
- Full Text
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10. Characterization of SnO2-based (68)Ge/ (68)Ga generators and (68)Ga-DOTATATE preparations: radionuclide purity, radiochemical yield and long-term constancy.
- Author
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Sudbrock F, Fischer T, Zimmermanns B, Guliyev M, Dietlein M, Drzezga A, and Schomäcker K
- Abstract
Background: With the increasing utilization of (68)Ge-(68)Ga radionuclide generators, (68)Ga labelled peptides like DOTATATE are receiving more attention in nuclear medicine. On the one hand, the long half-life of the parent nuclide (68)Ge is an enormous advantage for routine applications, but the question of the long-term stability of the (68)Ge breakthrough arises, which up to now has scarcely been investigated., Method: A sum of 123 eluates from four different (68)Ge-(68)Ga generators (iThemba Labs, Faure, South Africa) and 115 samples of the prepared radiopharmaceutical (68)Ga-DOTATATE were measured first with a dose calibrator and again after decay of the eluted (68)Ga via gamma-ray spectrometry. A complete decay curve was recorded for one sample eluate. A further three eluates were eluted in ten fractions of 0.5 ml in order to obtain detailed information concerning the distribution of the two nuclides within the eluates. The influences of factors such as the amount of DOTATATE, addition of Fe(3+) salts and replacement of HEPES buffer with sodium acetate on the radiochemical synthesis were also tested., Results: The content of long-lived (68)Ge breakthrough increases over the entire period of use to more than 100 ppm. The labelling process with the chelator DOTA removes (68)Ge efficiently. The maximum activity found in the residues of the radiopharmaceuticals investigated in this study was below 10 Bq in nearly all cases. In many cases (12% of the labelled substance), the long-lived parent nuclide could not be identified at all. The labelling process is still viable for reduced amounts of the chelator and with acetate buffer., Conclusion: Effective doses received by the patient from (68)Ge in the injected radiopharmaceutical (68)Ga-DOTATATE are lower than 0.1 μSv and are therefore practically negligible, especially when compared with the contribution of the PET radiopharmaceutical itself. Gamma-ray spectrometry as recommended by the European Pharmacopeia is suitable for quantification of radionuclidic impurities.
- Published
- 2014
- Full Text
- View/download PDF
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