👤 Jai Jun Choung

Cholinergic dysfunction is a key contributor to cognitive impairment observed in aging and neurodegenerative disorders such as Alzheimer's disease (AD). Although acetylcholinesterase (AChE) inhibitors have been the mainstay of symptomatic treatment for over two decades, their limited efficacy and adverse effects underscore the need for alternative therapeutic approaches. Recent evidence indicates that mechanical stimulation can modulate neuronal and glial signaling through mechanotransduction, suggesting a potential strategy to enhance cognitive function via non-pharmacological means. Here, we developed a head-mounted vibrotactile stimulation system (HVSS) that delivers controlled vibration to the cranium and evaluated its effects in a pharmacological model of acute cholinergic dysfunction induced by scopolamine. To this end, male C57BL/6 mice received scopolamine (1 mg/kg, i.p.; on days 7, 14, and 28) and were exposed to daily vibrotactile stimulation at 20, 40, or 80 Hz for 28 days. Behavioral performance was assessed using passive avoidance and Morris water maze tests, followed by biochemical and histological analyses. HVSS at 40 Hz and 80 Hz significantly improved cognitive performance, enhanced hippocampal cholinergic function, reduced oxidative damage, and upregulated memory-related signaling genes, including BDNF, PI3K, AKt, ERK1/2, CREB, and CAMK4. These findings suggest that high-frequency HVSS improves memory hippocampal cholinergic function via activation of memory-related signaling pathways, highlighting its potential as a safe, non-pharmacological neuromodulatory strategy for cholinergic dysfunction-related cognitive decline. Show less

The pathologic features of membranous lupus nephritis (MLN) are occasionally encountered in secondary membranous nephropathy (sMN) without overt clinical evidence of systemic lupus erythematosus. Moreover, some sMN with lupus-like features (lupus-like membranous nephropathy [LL-MN]) have a clinical presentation more typical of primary membranous nephropathy (pMN). Based on the confounding clinical and pathologic presentation, it is unclear how to categorize and treat these patients. We performed immunohistochemical staining for recently discovered target antigens associated with MN -NELL-1, THSD7A, and EXT1/2 and compared the clinicopathologic presentation of patients with LL-MN to those with pMN and MLN. From 2015 to 2020, there were 21 patients with MLN and 99 with MN, of which 59% were diagnosed pMN and 41% sMN. 44% of sMN patients showed lupus-like features (LL-fx). All LL-MN patients were negative for PLA2R and NELL1, but 12% were positive for EXT1/2. 50% of LL-MN patients had an identifiable systemic disease, of which 56% were autoimmune disease (AD) and 44% infection. Compared to pMN, LL-MN had a higher incidence of underlying AD (p = 0.02). Within pMN, 24% also had LL-fx (LL-pMN), and all but 1 were PLA2R- (78%) or NELL1-positive (15%). Only 5% of pMN patients had an AD, 66% of which showed LL-fx. Most idiopathic LL-MN were treated and behaved clinically similarly to pMN. There were no differences in outcome in terms of progression toward end-stage renal disease or mortality between LL-MN versus pMN and MLN. LL-MN appears to have a significant association with underlying AD and has a subset showing EXT1/2 positivity, whereas most LL-pMN and idiopathic LL-MN likely represent an atypical pathologic presentation of pMN. Show less

A 26year old east African professional athlete presented to the obstetric clinic for a routine visit at 36 weeks gestation. She had a history of Right Ventricular Outflow Tract - Ventricular Tachycardia (RVOT-VT) with an episode of cardiac arrest in the past, and had been treated with ablation 4 years earlier. Her current visit was uneventful, her pregnancy progressing normally. Following the visit she went to a local restaurant where she suffered a cardiac arrest that was unresponsive to therapy. Chest compressions were continued from the time of her collapse until an emergency caesarian section was performed, delivering a healthy female infant. At autopsy a focal area of subtle pallor and myocardial thinning was present at the apex of the right ventricle. Histology showed myocyte degeneration and loss with focal full thickness replacement of myocardium by adipose tissue, consistent with the fatty form of arrhythmogenic right ventricular cardiomyopathy (ARVC). Molecular studies revealed a variant of unknown significance in the MYBPC3 gene, but no variant known to be associated with ARVC. In view of the subtlety of the lesion on gross examination this diagnosis could have been easily missed, emphasizing the importance of performing histologic examination of subtle gross cardiac lesions. Show less