However, this phenomenon has rarely been observed in vivo without exogenous factors.

Helicobacter pylori infection and NSAIDs are considered the two most important exogenous factors in ulcer disease.

Whereas the effect of exogenous factors has been extensively investigated, endogenous, host-mediated mechanisms have remained largely unexplored.

These characteristics suggest that endogenous and exogenous factors modify disease expression and areas of emphasis for future investigation.

Somatic cell reprogramming by exogenous factors requires cooperation with transcriptional co-activators and co-repressors to effectively remodel the epigenetic environment.

In humans it is difficult to separate changes related to exogenous factors from those directly related to the aging process.

Here we present mice that develop pathology from non-mutant human tau, in the absence of other exogenous factors, including beta-amyloid.

In addition, evidence has accumulated that distinct states of pluripotency can interconvert through the modulation of both cell-intrinsic and exogenous factors.

HIV quantification has increased our knowledge about the natural history of the HIV infection and the influences of exogenous factors on HIV replication.

"Well, we could adjust the model to account for exogenous factors," said the bearded modeler.