Parkinson's disease (PD) is one of the most common neurodegenerative diseases, which is characterized by progressive degeneration of nigrostriatal dopaminergic neurons. There is a growing consensus that mitochondrial dysfunction and oxidative stress play a crucial role in PD pathogenesis. Sirtuin3 (SIRT3) is the major mitochondria NAD(+)-dependent deacetylase that acts as a regulator of mitochondrial protein function; it is essential for maintaining mitochondrial integrity. Although SIRT3 was reported to have anti-oxidative stress activity in an in vitro study, there is no explicit in vivo evidence for the involvement of SIRT3 in the etiology of PD. The present study shows that SIRT3 null mice do not exhibit motor and non-motor deficits compared with wild-type controls. However, SIRT3 deficiency dramatically exacerbated the degeneration of nigrostriatal dopaminergic neurons in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice. SIRT3 null mice exposed to MPTP also exhibited decreased superoxide dismutase 2, a specific mitochondrial antioxidant enzyme, and reduced glutathione peroxidase expression compared with wild-type controls. Taken together, these findings strongly support that SIRT3 has a possible role in MPTP-induced neurodegeneration via preserving free radical scavenging capacity in mitochondria.
Patient: Male, 60Final Diagnosis: Non-islet cell tumor hypoglycemia (NICTH) associated with gastrointestinal stromal tumor (GIST)Symptoms: HypoglycemiaMedication: —Clinical Procedure:—Specialty: Gastroenterology and HepatologyObjective:Rare diseaseBackground:Non-islet cell tumor hypoglycemia (NICTH) is a newly recognized, but uncommon, paraneoplastic syndrome that is associated with tumors of mesenchymal origin. We report a case of NICTH associated with a gastrointestinal stromal tumor (GIST).Case Report:A 60-year-old man presented to the emergency department of our hospital after being found unconscious in his home. His serum blood glucose on hospital admission was 40 mg/dL. He reported a three-month history of diffuse abdominal pain, fatigue, and blurred vision. Laboratory medicine investigations showed reduced levels of insulin, C-peptide, insulin-like growth factor binding protein (IGFBP)-3, and insulin-like growth factor (IGF)-1, but his IGFBP-2 was increased. Computed tomography (CT) scan of the chest and abdomen showed an abdominal mass that involved the small bowel, mesentery, and omentum, with lesions in the right lung and the left rib. Histopathology of a CT-guided biopsy of the abdominal mass showed a low-grade sarcomatous spindle cell neoplasm that was positive for CD117 using immunohistochemistry and with an exon 11 c-KIT mutation. These findings were consistent with a diagnosis of GIST and treatment with imatinib commenced.Conclusions:This case report has shown that hypoglycemia in the setting of low levels of insulin, C-peptide, IGF-1, and IGFBP-3 is suggestive of a diagnosis of NICTH, which should be investigated for an underlying source, which in this case, was confirmed to be a malignant GIST.
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