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Stem Cell Biology: An Overview
Published in Jyoti Ranjan Rout, Rout George Kerry, Abinash Dutta, Biotechnological Advances for Microbiology, Molecular Biology, and Nanotechnology, 2022
Down’s syndrome is caused by an extra copy of chromosome 21. Briggs et al. (2013) have utilized the IPSCS research to identify the molecular networks associated with the pathogenesis of Down’s syndrome. IPSCS have been utilized in the field of neurogenerative disorders like Parkinson’s disease (PD) in which there occurs a loss of dopaminergic neurons of substantia nigra. The treatment of PD had always been a difficult task because the neurons have already been lost by the time the PD gets clinically manifested. Due to this, the mechanism of this disease has not been explored. Nguyen et al. have used IPSCS and studied G2019S mutation in leucine-rich repeat of kinase 2 (LRRK2) gene, which has been reported in sporadic and familial PD cases. Hence, disease modeling using IPSCS research provides an improved understanding of the molecular mechanisms driving a disease.
Physiological and pathophysiological implications of hydrogen sulfide: a persuasion to change the fate of the dangerous molecule
Published in Journal of the Chinese Advanced Materials Society, 2018
Jan Mohammad Mir, Ram Charitra Maurya
DS, in which chromosome 21 is a trisomy, is a common condition characterized by impaired brain growth and maturation, resulting in mental retardation. Another characteristic of DS is its association with an Alzheimer’s type of dementia in elderly adults. CBS is encoded on chromosome 21 (21q22.3) and the defective enzyme causes homocystinuria, which is characterized by mental retardation, skeletal abnormalities, and vascular thromboembolic complications. Expression of CBS is 12 times greater in myeloblasts of DS children than those of normal individuals, while CBS protein levels in DS brains are approximately three times greater than normal. CBS is localized to astrocytes that surround senile plaques in the brains of DS patients with Alzheimer’s type of dementia. Levels of thiosulfate, a metabolite of H2S, in urine are significantly greater in DS patients compared to normal individuals. It is interesting that a polymorphism of the CBS allele is significantly underrepresented in children with high intelligence quotients, suggesting that increased production of H2S by over expressed CBS in DS patients may be the cause of the neurological impairments.
Fluoride and human health: Systematic appraisal of sources, exposures, metabolism, and toxicity
Published in Critical Reviews in Environmental Science and Technology, 2020
Humayun Kabir, Ashok Kumar Gupta, Subhasish Tripathy
The literature has reported some correlation between maternal serum and umbilical cord blood plasma F− levels, thus suggesting that F− may cross the placenta and incorporate into the developing embryo (Gupta, Seth, Gupta, & Gavane, 1993; Malhotra, Tewari, Chawla, Gauba, & Dhall, 1993). Usually, the umbilical cord blood F− level is nearly 60% that in maternal blood serum (Shimonovitz et al., 1995). Consequently, embryos developing with high maternal F− intake are at high risk of F− toxicity. High F− intake shows an adverse developmental effect in experimental animals, but human studies have been mostly inconclusive (Doull et al., 2006). Researchers have reported three types of developmental disorders from excess F− intake: closed spina bifida, sudden infant death, and Down’s syndrome (Doull et al., 2006). Two studies in India have reported an increased risk of closed spina bifida (abnormal opening in bone) in school-aged children consuming drinking water with F− above the permissible limit (Gupta, Gupta, Seth, & Chaturvedi, 1995). However, further well-controlled, extensive studies are required to make conclusions regarding the risk of spina bifida, occulta, and F− exposure. The literature contains much less data on sudden infant death. Down’s syndrome is a genetic disorder in which three copies of chromosome 21 instead of two are present in the embryo, thus resulting in both physical and mental disorders. Three studies before 1970 reported the relationship between down syndrome and fluoridation but were flawed because of improper methodology (Lilienfeld, 1969; Rapaport, 1956, 1963 as cited in Doull et al., 2006). Later, several other studies were unable to replicate Rapaport’s findings. In 1980, Erickson (1980) analyzed a population of more than 250,000 individuals from 44 cities and was unable to confirm Rapaport’s conclusions. Although an ad hoc (1991) committee rejected Rapaport’s report, they recommended study of developmental toxicity at multiple dosage levels (USPHS, 1991). A recent study has systematically reviewed the incidence of Down’s syndrome and water F− levels, but the results were inconclusive (Whiting, McDonagh, & Kleijnen, 2001).