Citations

The cardiovascular responses to sympathomimetic agents, the norepinephrine (NE) content in peripheral tissues, and the tissue content and cardiovascular effects of neuropeptide Y (NPY) were examined in anesthetized adult rats with guanethidine-induced sympathectomy (GuSx). We observed blunted pressor responses to tyramine, exaggerated pressor responses to phenylephrine, and markedly reduced NE contents in the atrium, femoral artery, superior cervical ganglion (SCG), and sciatic and vagus nerves. When tyramine responses were corrected for the NE content in the SCG, GuSx rats were similar to controls. A depletion of NPY levels in tissue resulted in an increased sensitivity to the pressor effects of intravenous NPY administration. GuSx, therefore, reproduces findings of postganglionic adrenergic failure in humans. Responses to the administration of sympathomimetic agents may reflect the degree of noradrenergic denervation. NPY may be a potential marker of chronic postganglionic sympathetic denervation in cardiovascular tissue.

Background: There is growing interest in white matter (WM) imaging with positron emission tomography (PET). Objectives: We studied the association of cognitive function in late multiple sclerosis (MS) with cortical and WM Pittsburgh compound-B PET (PiB-PET) binding. Methods: In the population-based Mayo Clinic Study of Aging, 24 of 4869 participants had MS (12 underwent PiB-PET). Controls were age and sex matched (5:1). We used automated or semi-automated processing for quantitative image analyses and conditional logistic regression for group differences. Results: MS patients had lower memory ( p = 0.03) and language ( p = 0.02) performance; smaller thalamic volumes ( p = 0.003); and thinner temporal ( p = 0.001) and frontal ( p = 0.045) cortices on magnetic resonance imaging (MRI) than controls. There was no difference in global cortical PiB standardized uptake value ratios between MS and controls ( p = 0.35). PiB uptake was lower in areas of WM hyperintensities compared to normal-appearing white matter (NAWM) in MS ( p = 0.0002). Reduced PiB uptake in both the areas of WM hyperintensities ( r = 0.65; p = 0.02) and NAWM ( r = 0.69; p = 0.01) was associated with decreased visuospatial performance in MS. Conclusion: PiB uptake in the cortex in late MS is not different from normal age-matched controls. PiB uptake in the WM in late MS may be a marker of the large network structures’ integrity such as those involved in visuospatial performance.

ABSTRACTIntroduction: Autosomal dominant haploinsufficiency of GATA2 causes monocytopenia and natural killer cell lymphopenia, resulting in predisposition to mycobacterial, fungal, and viral infections. Methods: Herein we report on the clinical, serologic, electrophysiologic, and pathologic evaluations of a 29‐year‐old woman with GATA2 haploinsufficiency and active Epstein–Barr virus (EBV) infection complicated by subacute painful neuropathy. Results: Nerve conduction and electromyography studies showed predominantly demyelinating sensorimotor polyradiculoneuropathy. Lumbar spine MRI showed thickening and enhancement of the cauda equina nerve roots. Serum and cerebrospinal fluid anti‐IgG and IgM EBV capsid and nucleic acid antibodies were positive. Sural nerve biopsy showed microvasculitis and an increased frequency of fibers with segmental demyelination. Intravenous immunoglobulin and steroids improved the patient's neuropathy. Conclusion: GATA2 mutation–related immunodeficiency may predispose to EBV‐associated subacute demyelinating polyradiculoneuropathy by both viral susceptibility and immune dysregulation. In patients who present in this manner, immunodeficiency syndromes should be considered when lymphomatous infiltration is excluded. Immunotherapy can be helpful. Muscle Nerve 57: 150–156, 2018