Biomedical subjects

Alexander Neumann

Publications and source records attributed to Alexander Neumann.

3 recordsLinked to original sources

PubMed2025

Genome-wide association study of adolescent-onset depression.

Adolescent depression is a heritable psychiatric condition with rising global prevalence and severe long-term outcomes, yet its biological underpinnings remain poorly understood. We conducted the first genome-wide association study of adolescent-onset depression, comprising 102,428 cases (diagnosis or clinical symptom thresholds) and 286,911 controls, including diverse ancestries. Cross-ancestry meta-analysis identified 52 independent variants across 17 loci; European-only analysis found 61 variants at 29 loci, with a SNP-based heritability of 9.8%. Comparative analyses revealed two genes unique to adolescent-onset versus lifetime depression, enriched in neuronal subtypes, and two genes as potential drug repurposing targets. Polygenic scores were associated with adolescent-onset depression across ancestries, persistent depression trajectories, more severe outcomes, as well as reduced cortical volume, surface area and white matter integrity. Genetic correlation and Mendelian randomisation analyses support shared genetic liability and causal links with early puberty and modifiable health and behavioural risk factors. These findings uncover novel genetic loci and refine biological pathways underlying adolescent-onset depression, revealing age-specific mechanisms and early intervention opportunities.

Journal Article↗

PubMed2005

[Continuity in personnel--change in contents: German physiologists in National Socialism and in the Federal Republic of Germany].

This paper illustrates how German physiologists during the Second World War succeeded in making a case for the relevance of their research for the war effort. In this way the paper contributes to the recent historical debate about how scientists--in this case the physiologists--could enforce their interests within the National Socialist system and to what extent they were "misused" by the political and military leaders. Most scientists were able to continue their careers in the new political system after 1945, using the old scientific network from the National Socialist era. They successfully changed their research topics, responding quickly to the new challenges in peace. As a typical example the career of the physiologist Hans Schäfer is described in this article.

Biomedical Research↗

PubMed2004

Automated volumetric flow quantification using angle-corrected color Doppler image.

We have developed a fully automated method for measuring volumetric blood flow with angle-corrected blood velocity from a color Doppler image. By computing the blood flow vector through a conduit, the angle of incidence between the direction of ultrasound beam and the direction of blood flow can be measured to correct the underestimated blood velocity. This correction immediately contributes to the improvement of measurement accuracy. The developed method also enhances the conduit identification procedure that is one of the most important factors affecting the accuracy of volumetric measurement. To evaluate the validity of the developed algorithm, experimental studies had been applied to 21 healthy subjects and 10 patients. Volumetric flows were measured from a color Doppler image of the left ventricular outflow track, which were compared with blood volumes that were measured by traditional pulsed-wave (PW)-Doppler technique. The mean stroke volume difference between two methods was -0.45 +/- 11.7 (mean +/- SD). The proposed algorithm is a viable method for determining blood flow volume in an automated fashion.

Blood Flow Velocity↗