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Nathan Goodyear

The implication of neuroactive steroids in Tourette syndrome pathogenesis: a ... - 0 views

  • The typical onset of TS occurs at 6–7 years of age and is characterized by the appearance of simple, recurrent motor tics, followed by the manifestation of phonic tics after several months [12]. In most children, TS symptoms undergo a progressive exacerbation, which reaches its zenith at the beginning of puberty (11–12 years of age), and is then followed by a gradual remission in the majority of patients
  • 30–40% of TS-affected children retain their symptoms in adulthood
  • Multiple neurotransmitters have been implicated in TS, including dopamine (DA), serotonin, norepinephrine, acetylcholine, glutamate and γ-amino-butyric acid (GABA)
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  • ample evidence supports the involvement of DAergic dysfunctions in TS
  • male gender is a major risk factor for TS (with a male:female prevalence ratio estimated at ~4:1)
  • the typical age of onset coincides with adrenarche (6–7 years old); symptoms increase in severity until the beginning of puberty (12 years old) and then undergo a spontaneous amelioration, which becomes apparent with the end of puberty (at 18–19 years of age)
  • TS is diagnosed later in females than males
  • female gender may predict greater tic severity in adulthood
  • a number of clinical observations showed that tics in TS patients could be exacerbated by anabolic androgens
  • steroidogenic enzymes and androgen receptors may serve as putative therapeutic targets for this disorder
  • Unlike males, tic severity is typically increased after puberty in females
  • 26% of females were found to experience exacerbation of tics in the estrogenic phase of the menstrual cycle, and this phenomenon was found to be correlated with increased tic severity at menarche
  • biochemical hallmark of adrenarche is the acquisition of 17,20 lyase activity by cytochrome P450 C17 (CYP17A1)
  • increased synthesis of dehydroepiandrosterone (DHEA) and androstenedione, which leads to the growth of axillary and pubic hair as well as enhancement in the oiliness of the skin
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    interesting read on hormones and tourette's.. Proposed that 5 alpha reductase activity is involved in worsening of tics.  This makes sense as Testosterone in men with low T is known to increase dopamine and dopaminergic dysfunction is known to play a role in tourette's;  the clinical presentation of girls vs boys is very different.  The authors of this article propose that 5 alpha reductase activity controls a back door method where by progesterone is converted to androgens.
Nathan Goodyear

Growth Inhibition of Ovarian Tumor-Initiating Cells by Niclosamide | Molecular Cancer T... - 0 views

  • Ovarian cancer is the most lethal gynecologic malignancy and the fifth-most cause of overall cancer death of women in developed countries
  • An increasingly accepted cancer stem cell hypothesis regards tumors as caricatures of normal organs, possessing a hierarchy of cell types, at various stages of aberrant differentiation, descended from precursor tumor-initiating cells (TIC) cells that are highly resistant to conventional cytotoxics
  • Significant changes of gene expression in 2,928 genes were identified after niclosamide treatment for different time periods
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  • uncoupling of mitochondrial oxidative phosphorylation is believed to be its anti-helminthic mechanism of action
  • we hypothesized that niclosamides antagonistic effects on OTICs could, in part, be due to its disruption of metabolism
  • Our results showed that genes participating in protein complexes of oxidative phosphorylation were downregulated
  • niclosamide treatment resulted in a more than 20% increase in reactive oxygen species (ROS) in cultured OTICs
  • niclosamide, which has proved to be safe and effective for the past 2 decades against numerous parasites, inhibited OTIC growth both in vitro and in vivo
  • niclosamide represses metabolic enzymes responsible for bioenergetics, biosynthesis, and redox regulation specifically in OTICs, presumably leading to mitochondrial intrinsic apoptosis pathways, loss of tumor stemness, and growth inhibition
  • Niclosamide is believed to inhibit mitochondrial oxidative phosphorylation
  • Niclosamide was reported to inactivate NF-κB, causing mitochondrial damage and the generation of ROS, leading to apoptosis of leukemic stem cells
  • niclosamide were identified in a screen for mTOR-signaling inhibitors
  • mTOR was reported to maintain stemness properties of HSCs by inhibiting mitochondrial biogenesis and ROS levels (39), implying that mTOR inhibitors (such as niclosamide) may interfere with mitochondria and various metabolic pathways in TICs via disruption of antioxidant responses
  • We observed Wnt hyperactivity in OTICs, in agreement with previous hypotheses of Wnt inhibitor effectiveness as an ovarian cancer therapy
  • niclosamide has now been independently identified in screens for Wnt inhibitors
  • downregulation of the Wnt/β-catenin target oncogenes survivin and c-Myc
  • ovarian carcinogenesis, the cell-to-cell signaling pathway Notch (8), were also suppressed by niclosamide (data not shown). These results agree with another recent niclosamide study in leukemia (49), and it has been widely hypothesized that disruption of Notch signaling may represent a highly effective therapy for ovarian and other solid tumors, via its essentiality to maintaining TIC stemness
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    Niclosamide, common anti-parasitic medication, inhibits cellular metabolism and increases ROS; both of which provide powerful anti-proliferative, anti-cancer treatment mechanism in TICs. Powerful target therapy for cancer stem cells. Also shown to inhibit Wnt stimulated oncogenes survivin and c-Myc, disrupts Notch signaling, inactivates NF-kappaBeta, and inhibits mTOR-signaling.  This has been found in in vitro and in vivo studies.
Nathan Goodyear

Early Thimerosal Exposure and Neuropsychological Outcomes at 7 to 10 Years - NEJM - 0 views

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    Increasing mercury exposure associated with increasing tics in children.
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