University of Duisburg-Essen

About: University of Duisburg-Essen is a education organization based out in Essen, Nordrhein-Westfalen, Germany. It is known for research contribution in the topics: Population & Transplantation. The organization has 16072 authors who have published 39972 publications receiving 1109199 citations.

A solid-state NMR investigation of the structure of nanocrystalline hydroxyapatite.

Abstract: Nanocrystalline hydroxyapatite (HAp) prepared by a precipitation route was investigated. The X-ray diffraction (XRD) powder patterns of the elongated nanocrystals with a typical diameter of about 10 nm and length of 30-50 nm (by transmission electron microscopy (TEM)) revealed the presence of HAp with significantly broadened XRD reflections. However, Ca deficiency was found, as the Ca/P ratio was 1.5 only (so-called calcium-deficient hydroxyapatite (CDHA)), and not 1.67. This Ca deficiency of nanocrystalline HAp is explained using NMR. It is shown unambiguously that (i) the nanocrystals consist of a crystalline core and a (disordered) surface region with a relative phosphate content of about 1:1, (ii) the crystalline core is HAp, and (iii) the surface region is dominated by hydrogen phosphate anions (with no hydroxyapatite-like structural motif) and structural water (hydrate). From the relative phosphate content and taking into account the crystal shape, the thickness of the surface layer along the main crystal axis could be estimated to be about 1 nm, and the average chemical composition of the surface layer has been determined. Finally, a Ca/P ratio of 1.52 was estimated from the NMR data that compares well with the value of 1.51 from chemical analysis. The important consequences are that the surface of nanocrystalline HAp has nothing in common with the bulk composition and that the chemistry of such materials (e.g. the binding of protein molecules to phosphate surfaces) must be reconsidered.

Efficacy and Safety Outcomes in Patients With Advanced Melanoma Who Discontinued Treatment With Nivolumab and Ipilimumab Because of Adverse Events: A Pooled Analysis of Randomized Phase II and III Trials.

Abstract: Purpose Approximately 40% of patients with advanced melanoma who received nivolumab combined with ipilimumab in clinical trials discontinued treatment because of adverse events (AEs). We conducted a retrospective analysis to assess the efficacy and safety of nivolumab plus ipilimumab in patients who discontinued treatment because of AEs. Methods Data were pooled from phase II and III trials of patients who received nivolumab 1 mg/kg plus ipilimumab 3 mg/kg, every 3 weeks for four doses, followed by nivolumab monotherapy 3 mg/kg every 2 weeks (N = 409). Efficacy was assessed in all randomly assigned patients who discontinued because of AEs during the induction phase (n = 96) and in those who did not discontinue because of AEs (n = 233). Safety was assessed in treated patients who discontinued because of AEs (n = 176) at any time and in those who did not discontinue because of AEs (n = 231). Results At a minimum follow-up of 18 months, median progression-free survival was 8.4 months for patients who discontinued treatment because of AEs during the induction phase and 10.8 months for patients who did not discontinue because of AEs ( P = .97). Median overall survival had not been reached in either group ( P = .23). The objective response rate was 58.3% for patients who discontinued because of AEs during the induction phase and 50.2% for patients who did not discontinue. The vast majority of grade 3 or 4 AEs occurred during the induction phase, with most resolving after appropriate management. Conclusion Efficacy outcomes seemed similar between patients who discontinued nivolumab plus ipilimumab treatment because of AEs during the induction phase and those who did not discontinue because of AEs. Therefore, even after discontinuation, many patients may continue to derive benefit from combination therapy.

ERCC1 Isoform Expression and DNA Repair in Non-Small-Cell Lung Cancer

Abstract: Background The excision repair cross-complementation group 1 (ERCC1) protein is a potential prognostic biomarker of the efficacy of cisplatin-based chemotherapy in non–small-cell lung cancer (NSCLC). Although several ongoing trials are evaluating the level of expression of ERCC1, no consensus has been reached regarding a method for evaluation. Methods We used the 8F1 antibody to measure the level of expression of ERCC1 protein by means of immunohistochemical analysis in a validation set of samples obtained from 494 patients in two independent phase 3 trials (the National Cancer Institute of Canada Clinical Trials Group JBR.10 and the Cancer and Leukemia Group B 9633 trial from the Lung Adjuvant Cisplatin Evaluation Biology project). We compared the results of repeated staining of the entire original set of samples obtained from 589 patients in the International Adjuvant Lung Cancer Trial Biology study, which had led to the initial correlation between the absence of ERCC1 expression and platinum response, ...