Publications by authors named "U Klemm"

Cyanine derivatives are organic dyes widely used for optical imaging. However, their potential in longitudinal optoacoustic imaging and photothermal therapy remains limited due to challenges such as poor chemical stability, poor photostability, and low photothermal conversion. In this study, we present a new structural modification for cyanine dyes by introducing a strongly electron-withdrawing group (barbiturate), resulting in a new series of barbiturate-cyanine dyes (BC810, BC885, and BC1010) with suppressed fluorescence and enhanced stability.

View Article and Find Full Text PDF

Optoacoustic (or photoacoustic) imaging promises micron-resolution noninvasive bioimaging with much deeper penetration (>cm) than fluorescence. However, optoacoustic imaging of enzyme activity would require loud, photostable, NIR-absorbing molecular contrast agents, which remain unknown. Most organic molecular contrast agents are repurposed fluorophores, with severe shortcomings of photoinstability or phototoxicity under optoacoustic imaging, as consequences of their slow S→S electronic relaxation.

View Article and Find Full Text PDF

Fluorescence molecular endoscopy (FME) is emerging as a "red-flag" technique with potential to deliver earlier, faster, and more personalized detection of disease in the gastrointestinal tract, including cancer, and to gain insights into novel drug distribution, dose finding, and response prediction. However, to date, the performance of FME systems is assessed mainly by endoscopists during a procedure, leading to arbitrary, potentially biased, and heavily subjective assessment. This approach significantly affects the repeatability of the procedures and the interpretation or comparison of the acquired data, representing a major bottleneck towards the clinical translation of the technology.

View Article and Find Full Text PDF
Article Synopsis
  • Hematopoietic stem cells (HSCs) in bone marrow regenerate various blood cell lineages but can be affected by stress, with microRNAs (miRNAs) like miR-221/222 playing a significant role in this process.
  • Research showed that the loss of miR-221/222 in mice led to a drastic reduction in HSC pools and changes in myeloid/erythroid precursor levels, resembling the effects of social stress.
  • Single-cell RNA sequencing identified over 80 genes affected by stress, with specific immediate early genes (IEGs) emerging as potential targets for miR-221/222, linking them to processes that influence blood cell development.
View Article and Find Full Text PDF

In previous studies, Mott cells, an unusual form of plasma cells containing Ig-inclusion bodies, were frequently observed in peripheral lymphoid tissues in our IgM Fc receptor (FcμR)-deficient (KO) mouse strain. Because of discrepancies in the reported phenotypes of different Fcmr KO mouse strains, we here examined two additional available mutant strains and confirmed that such enhanced Mott-cell formation was a general phenomenon associated with FcμR deficiency. Splenic B cells from Fcmr KO mice clearly generated more Mott cells than those from WT mice when stimulated in vitro with LPS alone or a B-1, but not B-2, activation cocktail.

View Article and Find Full Text PDF