123 research outputs found
Age-related changes in T lymphocytes of patients with head and neck squamous cell carcinoma
Introduction
The number of aging cancer patients has increased continuously and will do so further in the future. The immune system of elderly people experiences critical changes over the time. Therefore, tumor-induced changes in the immune system are believed to differ in young and elderly cancer patients as well.
Methods
The effect of aging on the immune system was measured in peripheral blood lymphocytes (PBL) of healthy volunteers (n = 48, 21–84 yrs.) divided into three different age groups. Seventy years was set as a cut-off for defining subjects as elderly. Results were compared to two groups of adult cancer patients, which donated PBL and tumor infiltrating lymphocytes (TIL): young cancer patients (40–69 yrs.; blood: n = 13; TIL: n = 17) and elderly cancer patients (70–90 yrs.; blood: n = 20; TIL: n = 15) with head and neck squamous cell carcinoma (HNSCC). Frequencies and phenotypes of CD4+ and CD8+ T cells as well as regulatory T cells (Treg) were assessed by flow cytometry.
Results
We observed lower frequencies of CD8+ cytotoxic T cells during aging in both groups. Frequencies of tumor infiltrating regulatory T cells were significantly higher than in the peripheral blood but showed a significant decline in older tumor patients. With increasing age, expression of immunosuppressive CD73 and CCR7 was lower and expression of PD1 elevated on peripheral T cells in healthy volunteers and tumor patients.
Conclusion
Immunosenescence takes place in healthy donors and cancer patients. Our results suggest that in elderly tumor patients, the immune system is impaired and the tumor-induced immune escape is less pronounced. The increased expression of PD1 implies the potential for effective immunotherapies in elderly, as treatment with checkpoint inhibitors could be more beneficial for elderly HNSCC patients
The Sagebrush Steppe Treatment Evaluation Project (SageSTEP): A Test of State-and Transition Theory.
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Seed and seedling traits affecting critical life stage transitions and recruitment outcomes in dryland grasses
1. Seeding native plants is a key management practice to counter land degradation across
the globe, yet the majority of seeding efforts fail, limiting our ability to accelerate ecosystem
recovery.
2. Recruitment requires transitions through several seed and seedling stages, some of which
may have overriding influences on restoration outcomes. We lack, however, a general
framework to understand and predict differences in these critical demographic processes
across species. Functional traits influence fitness, and consequently, trait variation could provide
the basis for a framework to explain and predict variation in life stage transition probabilities.
3. We used seed and seedling traits, and field probabilities of germination, emergence, seedling
establishment, and survival for 47 varieties of drylands grasses under two watering treatments
to identify critical life stage transitions and quantify the effect of traits on cumulative
survival through the first growing season.
4. Variation in germination and emergence probabilities explained over 90% of the variation
in cumulative survival regardless of seedling survival probabilities or watering treatment, with
emergence probability being the strongest predictor of cumulative survival.
5. Coleoptile tissue density and seed mass had significant effects on emergence and germination,
respectively, explaining 10–23% of the variation in transition probabilities.
6. Synthesis and applications: While the majority of functional trait work has centred on linking
leaf and root traits to resource acquisition and utilization, our study demonstrates that
traits associated with germination and emergence may have prevailing influences on restoration
outcomes. A portion of these traits have been examined, but there is substantial opportunity
to identify other key traits driving these demographic processes. These advancements will
underpin our ability to develop trait-based frameworks for overcoming recruitment barriers
and facilitating recovery of degraded systems across the globe.Keywords: seeding, path analysis, seed mass, emergence, functional traits, coleoptile tissue density, germination, hydrothermal time, demograph
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