Publications by authors named "Hannah Litwa"

Maternal stress during reproduction can influence how offspring respond to stress later in life. Greater lifetime exposure to glucocorticoid hormones released during stress is linked to greater risks of behavioral disorders, disease susceptibility, and mortality. The immense variation in individual's stress responses is explained, in part, by prenatal glucocorticoid exposure.

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Selective serotonin reuptake inhibitors (SSRIs) are one of the most commonly prescribed antidepressants worldwide and recent data show significant impairment of fracture healing after treatment with the SSRI fluoxetine in mice. Here, we provide evidence that the negative effects of SSRIs can be overcome by administration of the beta-blocker propranolol at the time of fracture. First, in vitro experiments established that propranolol does not affect osteogenic differentiation.

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Hox genes are evolutionarily conserved transcription factors that during embryonic development function as master regulators of positional identity. In postnatal life, the function of Hox proteins is less clear: Hox genes are expressed during tissue repair, but in this context their function(s) are largely unknown. Here we show that Hox genes are expressed in periosteal stem/progenitor cells in a distribution similar to that during embryonic development.

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Aging is associated with impaired tissue regeneration. Stem cell number and function have been identified as potential culprits. We first demonstrate a direct correlation between stem cell number and time to bone fracture union in a human patient cohort.

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Article Synopsis
  • Vertebrates produce glucocorticoids, particularly during stressful times, which can influence the development and phenotypes of their offspring, especially when stress occurs during reproduction.
  • In a study with Japanese quail, researchers injected radioactive corticosterone into eggs to assess how much of it embryos were exposed to at different developmental stages.
  • Results showed that while higher doses initially led to greater radioactivity in the embryos, by day nine, the levels equalized across doses, indicating a potential metabolic process that reduces maternal corticosterone in the egg over time.
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Maintenance of hematopoietic stem cell (HSC) quiescence is critical for self-renewal and differentiation into mature lineages. Therefore, the ability to reliably detect abnormal HSC cycling is essential for experiments that seek to investigate abnormalities of HSC function. The ability to reproducibly evaluate cell cycle status in a rare cell subset requires careful optimization of multiple parameters during cell preparation and sample processing.

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Telomeres are highly conserved regions of DNA that protect the ends of linear chromosomes. The loss of telomeres can signal an irreversible change to a cell's state, including cellular senescence. Senescent cells no longer divide and can damage nearby healthy cells, thus potentially placing them at the crossroads of cancer and ageing.

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