Biomedical subjects

Christina Schmidt

Publications and source records attributed to Christina Schmidt.

4 recordsLinked to original sources

PubMed2025

An atlas of ferroptosis-induced secretomes.

Cells undergoing regulated necrosis systemically communicate with the immune system via the release of protein and non-protein secretomes. Ferroptosis is a recently described iron-dependent type of regulated necrosis driven by massive lipid peroxidation. While membrane rupture occurs during ferroptosis, a comprehensive appraisal of ferroptotic secretomes and their potential biological activity has been lacking. Here, we apply a multi-omics approach to provide an atlas of ferroptosis-induced secretomes and reveal a novel function in macrophage priming. Proteins with assigned DAMP and innate immune system function, such as MIF, heat shock proteins (HSPs), and chaperones, were released from ferroptotic cells. Non-protein secretomes with assigned inflammatory function contained oxylipins as well as TCA- and methionine-cycle metabolites. Interestingly, incubation of bone marrow-derived macrophages (BMDMs) with ferroptotic supernatants induced transcriptional reprogramming consistent with priming. Indeed, exposure to ferroptotic supernatants enhanced LPS-induced cytokine production. These results define a catalog of ferroptosis-induced secretomes and identify a biological activity in macrophage priming with important implications for the fine-tuning of inflammatory processes.

Ferroptosis↗

PubMed2006

Encoding difficulty promotes postlearning changes in sleep spindle activity during napping.

Learning-dependent increases in sleep spindle density have been reported during nocturnal sleep immediately after the learning session. Here, we investigated experience-dependent changes in daytime sleep EEG activity after declarative learning of unrelated word pairs. At weekly intervals, 13 young male volunteers spent three 24 h sessions in the laboratory under carefully controlled homeostatic and circadian conditions. At approximately midday, subjects performed either one of two word-pair learning tasks or a matched nonlearning control task, in a counterbalanced order. The two learning lists differed in the level of concreteness of the words used, resulting in an easier and a more difficult associative encoding condition, as confirmed by performance at immediate cued recall. Subjects were then allowed to sleep for 4 h; afterward, delayed cued recall was tested. Compared with the control condition, sleep EEG spectral activity in the low spindle frequency range and the density of low-frequency sleep spindles (11.25-13.75 Hz) were both significantly increased in the left frontal cortex after the difficult but not after the easy encoding condition. Furthermore, we found positive correlations between these EEG changes during sleep and changes in memory performance between pre-nap and post-nap recall sessions. These results indicate that, like during nocturnal sleep, daytime sleep EEG oscillations including spindle activity are modified after declarative learning of word pairs. Furthermore, we demonstrate here that the nature of the learning material is a determinant factor for sleep-related alterations after declarative learning.

Adult↗

PubMed2005

Octreotide versus octreotide plus interferon-alpha in endocrine gastroenteropancreatic tumors: a randomized trial.

BACKGROUND & AIMS: The effect of octreotide plus interferon-alpha versus octreotide monotherapy on the primary study end points of time to treatment failure (progression, death, stop of study treatment) and long-term survival was investigated in patients with progressive metastatic neuroendocrine foregut (mainly pancreatic) and midgut tumors. METHODS: One hundred nine of 125 registered patients were randomized starting in January 1995, and 105 patients (51 monotherapy, 54 combination treatment) were finally analyzed in March 2000. Tumor growth was assessed at 3-month intervals by computed tomography or magnetic resonance imaging. Long-term survival was studied up to April 2004 in all analyzed patients and in 9 patients not randomized because of stable disease. RESULTS: Partial tumor regression occurred in 2.9%, 1.9%, and 5.7% and stabilization of tumor growth in 44.8%, 27.6%, and 15.2% at 3, 6, and 12 months, respectively, with no significant differences between both treatment arms. In March 2000, 9.5% of patients were in treatment. Time to treatment failure and long-term survival did not differ significantly between the 2 groups, with a median survival of 32 and 54 months for the octreotide and the combination groups, respectively. Survival was longer in patients not randomized because of stable disease (median, 68 months) and in those with low nuclear Ki-67. A trend toward longer survival was shown for patients with slow spontaneous tumor growth before randomization. Patients responding to treatment lived longer than unresponsive patients. CONCLUSIONS: Combination treatment was not superior to monotherapy concerning progression-free and long-term survival. Patients responding to treatment and those with slow spontaneous tumor growth had a survival advantage.

Adolescent↗

PubMed2004

Microarrays for global expression constructed with a low redundancy set of 27,500 sequenced cDNAs representing an array of developmental stages and physiological conditions of the soybean plant.

BACKGROUND: Microarrays are an important tool with which to examine coordinated gene expression. Soybean (Glycine max) is one of the most economically valuable crop species in the world food supply. In order to accelerate both gene discovery as well as hypothesis-driven research in soybean, global expression resources needed to be developed. The applications of microarray for determining patterns of expression in different tissues or during conditional treatments by dual labeling of the mRNAs are unlimited. In addition, discovery of the molecular basis of traits through examination of naturally occurring variation in hundreds of mutant lines could be enhanced by the construction and use of soybean cDNA microarrays. RESULTS: We report the construction and analysis of a low redundancy 'unigene' set of 27,513 clones that represent a variety of soybean cDNA libraries made from a wide array of source tissue and organ systems, developmental stages, and stress or pathogen-challenged plants. The set was assembled from the 5' sequence data of the cDNA clones using cluster analysis programs. The selected clones were then physically reracked and sequenced at the 3' end. In order to increase gene discovery from immature cotyledon libraries that contain abundant mRNAs representing storage protein gene families, we utilized a high density filter normalization approach to preferentially select more weakly expressed cDNAs. All 27,513 cDNA inserts were amplified by polymerase chain reaction. The amplified products, along with some repetitively spotted control or 'choice' clones, were used to produce three 9,728-element microarrays that have been used to examine tissue specific gene expression and global expression in mutant isolines. CONCLUSIONS: Global expression studies will be greatly aided by the availability of the sequence-validated and low redundancy cDNA sets described in this report. These cDNAs and ESTs represent a wide array of developmental stages and physiological conditions of the soybean plant. We also demonstrate that the quality of the data from the soybean cDNA microarrays is sufficiently reliable to examine isogenic lines that differ with respect to a mutant phenotype and thereby to define a small list of candidate genes potentially encoding or modulated by the mutant phenotype.

Cluster Analysis↗