2 research outputs found
Time-of-Flight Secondary Ion Mass Spectrometry-Based Molecular Distribution Distinguishing Healthy and Osteoarthritic Human Cartilage
Osteoarthritis (OA) is a pathology that ultimately causes
joint destruction. The cartilage is one of the principal affected
tissues. Alterations in the lipid mediators and an imbalance in the
metabolism of cells that form the cartilage (chondrocytes) have been
described as contributors to the OA development. In this study, we
have studied the distribution of lipids and chemical elements in healthy
and OA human cartilage. Time of flight-secondary ion mass spectrometry
(TOF-SIMS) allows us to study the spatial distribution of molecules
at a high resolution on a tissue section. TOF-SIMS revealed a specific
peak profile that distinguishes healthy from OA cartilages. The spatial
distribution of cholesterol-related peaks exhibited a remarkable difference
between healthy and OA cartilages. A distinctive colocalization of
cholesterol and other lipids in the superficial area of the cartilage
was found. A higher intensity of oleic acid and other fatty acids
in the OA cartilages exhibited a similar localization. On the other
hand, CN<sup>–</sup> was observed with a higher intensity in
the healthy samples. Finally, we observed an accumulation of calcium
and phosphate ions exclusively in areas surrounding the chondrocyte
in OA tissues. To our knowledge, this is the first time that TOF-SIMS
revealed combined changes in the molecular distribution in the OA
human cartilage
“Afterlife Experiment”: Use of MALDI-MS and SIMS Imaging for the Study of the Nitrogen Cycle within Plants
As
part of a project to demonstrate the science of decay, a series
of mass spectrometry imaging experiments were performed. The aim was
to demonstrate that decay and decomposition are only part of the story
and to show pictorially that atoms and molecules from dead plants
and animals are incorporated into new life. Radish plants (Raphanus sativus) were grown hydroponically using
a nutrient system containing <sup>15</sup>N KNO<sub>3</sub> (98% labeled)
as the only source of nitrogen. Plants were cropped and left to ferment
in water for 2 weeks to create a radish “tea”, which
was used as a source of nitrogen for radish grown in a second hydroponics
experiment. After 5 weeks of growth, the radish plants were harvested
and cryosectioned, and sections were imaged by positive-ion MALDI
and SIMS mass spectrometry imaging. The presence of labeled species
in the plants grown using <sup>15</sup>N KNO<sub>3</sub> as nutrient
and those grown from the radish “tea” was readily discernible.
The uptake of <sup>15</sup>N into a number of identifiable metabolites
has been studied by MALDI-MS and SIMS imaging