While many ancient individuals, known and unknown, contributed to the subject, none equaled the impact of Euclid and his Elements of geometry, a book now 2,300 years old and the object of as much painful and painstaking study as the Bible.
Multiple factors, known and unknown, contribute to human breast cancer.
Notably, acute stress may induce known (eg, hypercapnia) and unknown factors contributing to increased production of endothelial NO.
Studies in our laboratory have suggested that one of the previously unknown factors contributing to breast cancer metastasis is genetic background.
The distinct level and high spread of disease may suggest the presence of regionally specific, as yet unknown, factors contributing to its emergence.
This finding suggests a potential existence of other unknown species contributing to electricity generation through a variety of ways beyond the accepted Geobacter or Shewanella species [ 13].
With the exception of inborn errors of thyroid hormone synthesis, the etiologic mechanism in most cases is unknown, thus contributing to the interest in identifying risk factors for congenital hypothyroidism [ 19].
This indicates 11q22 deletions as part of the explanation to the recurrent decreased YAP1 protein levels in breast cancer, but also supports the possibility of additional unknown mechanisms contributing to YAP1 protein loss in breast cancer [ 25, 31- 33].
Thus, as the fibroblasts and macrophages used in this study were obtained from premenopausal women, and it is unknown what contributing factor estrogens have on mammary macrophage function in this assay, the effects of ectopic estrogen stimulation in the humanization procedure were also investigated.
While some patients have specific, correctable causes of anaemia such as iron deficiency, the exact aetiology of anaemia in most patients with heart failure is unknown, although contributing mechanisms may include renal impairment, inflammation, inadequate production of erythropoietin, and unresponsiveness to erythropoietin.
