ABSTRACT
A large proportion of patients who survive cancer are rendered infertile as an unwanted side effect of oncotherapy. Currently accepted approaches for fertility preservation involve banking eggs/sperm/embryos or ovarian/testicular tissue before oncotherapy for future use. Such approaches are invasive, expensive, technically challenging and depend on assisted reproductive technologies (ART). Establishing a gonadal tissue bank (for cancer patients) is also fraught with ethical, legal and safety issues. Most importantly, patients who find it difficult to meet expenses towards cancer treatment will find it difficult to meet expenses towards gonadal tissue banking and ART to achieve parenthood later on. In this review an alternative strategy to regenerate non-functional gonads in cancer survivors by targeting endogenous stem cells that survive oncotherapy is discussed. A novel population of pluripotent stem cells termed very small embryonic-like stem cells (VSELs), developmentally equivalent to late migratory primordial germ cells, exists in adult gonads and survives oncotherapy due to their quiescent nature. However, the stem-cell niche gets compromised by oncotherapy. Transplanting niche cells (Sertoli or mesenchymal cells) can regenerate the non-functional gonads. This approach is safe, has resulted in the birth of fertile offspring in mice and could restore gonadal function early in life to support proper growth and later serve as a source of gametes. This newly emerging understanding on stem cells biology can obviate the need to bank gonadal tissue and fertility may also be restored in existing cancer survivors who were earlier deprived of gonadal tissue banking before oncotherapy.
ABSTRACT
Effective regulation of contents of tobacco products is one of the primary milestones to reduce negative health effects associated with the use of smokeless tobacco (SLT) products. As per the available sources, testing of some SLT products has been done on ad hoc basis, but there is a lack of comprehensive and periodic analysis of these products. In addition, the available results indicate huge variations among the levels of pH, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, N-nitrosonornicotine, benzo[a]pyrene, heavy metals and nicotine within different products as well as within different brands of the same product. This review was aimed to throw light on the variations and gaps in testing of SLT products and emphasize the need for strong policy regulation for monitoring the chemical constituents of these products.