11 research outputs found
Fetal cyclophosphamide exposure induces testicular cancer and reduced spermatogenesis and ovarian follicle numbers in mice
<div><p>Exposure to radiation during fetal development induces testicular germ cell tumors (TGCT) and reduces spermatogenesis in mice. However, whether DNA damaging chemotherapeutic agents elicit these effects in mice remains unclear. Among such agents, cyclophosphamide (CP) is currently used to treat breast cancer in pregnant women, and the effects of fetal exposure to this drug manifested in the offspring must be better understood to offer such patients suitable counseling. The present study was designed to determine whether fetal exposure to CP induces testicular cancer and/or gonadal toxicity in 129 and in 129.MOLF congenic (L1) mice. Exposure to CP on embryonic days 10.5 and 11.5 dramatically increased TGCT incidence to 28% in offspring of 129 mice (control value, 2%) and to 80% in the male offspring of L1 (control value 33%). These increases are similar to those observed in both lines of mice by radiation. <i>In utero</i> exposure to CP also significantly reduced testis weights at 4 weeks of age to ∼70% of control and induced atrophic seminiferous tubules in ∼30% of the testes. When the <i>in utero</i> CP-exposed 129 mice reached adulthood, there were significant reductions in testicular and epididymal sperm counts to 62% and 70%, respectively, of controls. In female offspring, CP caused the loss of 77% of primordial follicles and increased follicle growth activation. The results indicate that i) DNA damage is a common mechanism leading to induction of testicular cancer, ii) increased induction of testis cancer by external agents is proportional to the spontaneous incidence due to inherent genetic susceptibility, and iii) children exposed to radiation or DNA damaging chemotherapeutic agents <i>in utero</i> may have increased risks of developing testis cancer and having reduced spermatogenic potential or diminished reproductive lifespan.</p></div
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A Brief Review of Processing, Structure, Properties, and Sustainability of Artificial Silk Fibers
Silk spinning has evolved many times in nature enabling a variety of organisms to produce fibres boasting exceptional properties, notably high strength and toughness, through energy- and resource-efficient processes. This has motivated scientists to both understand natural silk spinning processes, and replicate such processes or create new processes to produce artificial silks for a range of applications, from biomedicine to engineering. In this literature review, we briefly present some natural silk production processes, and compare these to various approaches to processing artificial silks. The artificial silk processing methods we discuss use natural, recombinant or regenerated silk proteins as dope to then wet, microfluidic, dry, or electro- spin the filaments. We critically evaluate the structure and properties of the resultant artificial silks to natural silks. We then examine the sustainability of artificial silks, in comparison to natural silks, which are model eco-fibres, and other technical fibres, to encourage fore-thinking in the design of artificial silk production processes. A discussion on the future challenges in artificial silk production processes follows. This brief review is for an audience with limited prior knowledge on natural and artificial silks, but with some basic understanding of materials science