PurposeThe purpose of this study is to establish the validity of intracerebral hemorrhage (ICH) diagnoses in the Danish Stroke Registry (DSR) and the Danish National Patient Registry (DNPR).Patients and methodsWe estimated the positive predictive value (PPV) of ICH diagnoses for a sample of 500 patients from the DSR (patients recorded under ICH diagnosis) and DNPR (International Classification of Diseases, version 10, code I61) during 2010–2015, using discharge summaries and brain imaging reports (minimal data). We estimated PPVs for any ICH (a-ICH) and spontaneous ICH (s-ICH) alone. Furthermore, we assessed PPVs according to whether patients were recorded in both or only one of the registries. Finally, in a subsample with ICH diagnoses with access to full medical records and original imaging studies (extensive data, n=100), we compared s-ICH diagnosis and hemorrhage location after use of extensive vs minimal data.ResultsIn the DSR, the PPVs were 94% (95% CI, 91%–96%) for a-ICH and 85% (95% CI, 81%–88%) for s-ICH. In the DNPR, the PPVs were 88% (95% CI, 84%–91%) for a-ICH and 75% (95% CI, 70%–79%) for s-ICH. PPVs for s-ICH for patients recorded in both registries, DSR only, and DNPR only were 86% (95% CI, 82–99), 80% (95%CI, 71–87), and 49% (95%CI, 39–59), respectively. Evaluation of extensive vs minimal data verified s-ICH diagnosis in 98% and hemorrhage location in 94%.ConclusionThe validity of a-ICH diagnoses in DSR and DNPR is sufficiently high to support their use in epidemiologic studies. For s-ICH, validity was high in DSR. In DNPR, s-ICH validity was lower, markedly so for the small subgroup of patients only recorded in this registry. Minimal data including discharge summaries and brain imaging reports were feasible and valid for identifying ICH location.

Parkinson's disease is a neurodegenerative disease resulting in degeneration of midbrain dopaminergic neurons. Exploratory studies using human foetal tissue or predifferentiated stem cells have suggested that intracerebral transplantation of dopaminergic precursor cells may become an effective treatment for patients with Parkinson's disease. However, strategies for dopaminergic stem cell differentiation vary widely in efficiency, and better methods still need to be developed. Hypoxia Inducible Factor 1 (HIF‐1) is a transcription factor involved in the regulation of genes important for cellular adaption to hypoxia and low glucose supply. HIF‐1 is to a large degree regulated by the availability of oxygen as in its presence, the subunit HIF‐1α is degraded by HIF prolyl hydroxylase enzymes (HPHs). Stabilization of HIF‐1α through inhibition of HPHs has been shown to increase dopaminergic differentiation of stem cells and to protect dopaminergic neurons against neurotoxins. This study investigated the effects of noncompetitive (FG‐0041) and competitive (Compound A and JNJ‐42041935) HIF‐1α stabilizing compounds on the dopaminergic differentiation of human neural stem cells. Treatment with all HPH inhibitors at high oxygen tension (20%) resulted in HIF‐1α stabilization as assessed by immunocytochemistry for HIF‐1α and detection of increased levels of vascular endothelial growth factor in the conditioned culture medium. Following 10 days of HIF‐1α stabilization, the cultures displayed a slightly reduced proliferative activity and significantly increased relative levels of tyrosine hydroxylase‐positive dopaminergic neurons. In conclusion, HIF‐1α stabilization may represent a promising strategy for the generation of dopaminergic neurons intended for use in experimental in vitro studies and cell replacement therapies.