A pure fluid-filled intradural cyst associated with intradural disc herniation and possible pathogenesis: a case report

Background contextLumbar intradural disc herniation (IDH) is rare, and intradural cyst associated with IDH is quite rare. Only seven cases of an intradural cyst associated with lumbar disc herniation have been reported, and all were gas-filled cysts. We report the first case, to our knowledge, of a fluid-filled intradural cyst associated with IDH.PurposeTo report an extremely rare case of a fluid-filled intradural cyst associated with lumbar IDH and suggests the possible pathogenesis.Study designCase report.MethodsAn 82-year-old woman presented with right leg pain and motor weakness. Computed tomography and magnetic resonance imaging (MRI) scans showed calcified lumbar disc herniation and an intradural cystic mass at the L1–L2 level. An MRI, which was performed 2 years before admission, showed an IDH without a cyst at the same level.ResultsSurgical resection of the intradural cyst was performed. Intraoperative finding showed a fluid-filled intradural cyst with 1-cm diameter of displacing nerve rootlets. The cyst was connected with extradural cystic components through a ventral dural hole, but the tract was blocked by fibrous septum. Histopathologic examination showed a pseudocyst that consisted of degenerative cartilaginous and fibrous tissues, including degenerative disc materials. We concluded that the cyst was an intradural cyst transformed from the intradural disc fragment.ConclusionsThe current case is the first report to our knowlege of a fluid-filled intradural cyst associated with IDH. The possible mechanism may be focal degeneration and spontaneous absorption of the intradural disc with fluid production. Unlike the gas-filled intradural cysts, the cause of the pure fluid-filled cyst may be disconnection from the intervertebral vacuum because of a calcified disc and septation of the cyst.     

Change of bilateral difference in radial artery pulse morphology with one-side arm movement

Previous studies have demonstrated that the compliance of peripheral artery changes with arm movement. This study aimed to quantify the bilateral difference in radial artery pulse morphology with one-side arm movement. Twenty-four healthy subjects were recruited. Radial artery pulses were synchronously recorded from both arms, with one arm (left or right) at five different positions (90°, 45°, 0°, −45° and −90°) and the other arm at horizontal level (0°) as reference. Two types of indices of arterial pulse morphology were derived from the normalized arterial pulse signals: the waveform width corresponding to the 50%, 60% and 70% pulse amplitude (W₅₀, W₆₀, W₇₀) and the total area of normalized pulse waveform (A_pulse). No matter whether the moving arm was left or right arm, when compared with the other side reference arm, all the waveform widths decreased with arm moving from 90°, 45°, 0°, −45°, and −90°. The bilateral difference of W₅₀, W₆₀ and W₇₀ with the moving arm (either left or right) at 90°, 45° were significantly positive (both p < 0.01) and significantly negative at −90° (both p < 0.05). Meanwhile, no matter whether the moving arm is left or right, A_pulse decreased with arm moving from 90°, 45°, 0°, −45°, and −90°. The bilateral difference of A_pulse with the left moving arm were significantly positive at 45°, 90° (both p < 0.05). Meanwhile, the bilateral difference of A_pulse from the moving right arm was significantly positive at 90° and significantly negative at −45° and −90° (all p < 0.05). In summary, this study quantified the bilateral arterial pulse morphology between arteries with different compliances induced by a simple arm positioning procedure.     

Lead (Pb2+)-induced calcium oxalate crystallization ex vivo is ameliorated via inositol 1,4,5-trisphosphate receptor (InsP3R) knockdown in a Drosophila melanogaster model of nephrolithiasis

Nephrolithiasis causes severe pain and is a highly recurrent pathophysiological state. Calcium-containing stones, specifically calcium oxalate (CaOx), is the most common type accounting for approximately 75 % of stone composition. Genetic predisposition, gender, geographic region, diet, and low fluid intake all contribute to disease pathogenesis. However, exposure to environmental pollutants as a contribution to kidney stone formation remains insufficiently studied. Lead (Pb2+) is of particular interest as epidemiological data indicate that low-level exposure (BLL = 0.48–3.85 μM) confers a 35 % increased risk of developing CaOx nephrolithiasis. However, mechanisms underlying this association have yet to be elucidated. Drosophila melanogaster provide a useful genetic model where major molecular pathophysiological pathways can be efficiently studied. Malpighian tubules (MT) were isolated from either Wild-Type or InsP₃R knockdown flies and treated with oxalate (5 mM) ± Pb²⁺ (2μM) for 1 h. Following exposure, MTs were imaged and crystals quantified. CaOx crystal number and total area were significantly increased (˜5-fold) in Pb²⁺(pre-treatment) + oxalate-exposed MTs when compared to oxalate alone controls. However, CaOx crystal number and total crystal area in Pb²⁺ + oxalate-exposed InsP₃R knockdown MTs were significantly decreased (˜3-fold) indicating the role for principal cell-specific InsP₃R-mediated Ca²⁺ mobilization as a mechanism for Pb²⁺-induced increases in CaOx crystallization inset model of nephrolithiasis.     

Dances with black widow spiders: Dysregulation of glutamate signalling enters centre stage in ADHD

Attention-deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder with impairments across the lifespan. The persistence of ADHD is associated with considerable liability to neuropsychiatric co-morbidity such as depression, anxiety and substance use disorder. The substantial heritability of ADHD is well documented and recent genome-wide analyses for risk genes revealed synaptic adhesion molecules (e.g. latrophilin-3, LPHN3; fibronectin leucine-rich repeat transmembrane protein-3, FLRT3), glutamate receptors (e.g. metabotropic glutamate receptor-5, GRM5) and mediators of intracellular signalling pathways (e.g. nitric oxide synthase-1, NOS1). These genes encode principal components of the molecular machinery that connects pre- and postsynaptic neurons, facilitates glutamatergic transmission, controls synaptic plasticity and empowers intersecting neural circuits to process and refine information. Thus, identification of genetic variation affecting molecules essential for the formation, specification and function of excitatory synapses is refocusing research efforts on ADHD pathogenesis to include the long-neglected glutamate system.     

Higher concentrations of vitamin D in Canadian children with juvenile idiopathic arthritis compared to healthy controls are associated with more frequent use of vitamin D supplements and season of birth

A number of studies have demonstrated that patients with autoimmune disease have lower levels of vitamin D prompting speculation that vitamin D might suppress inflammation and immune responses in children with juvenile idiopathic arthritis (JIA).  The objective of this study was to compare vitamin D levels in children with JIA at disease onset with healthy children. We hypothesized that children and adolescents with JIA have lower vitamin D levels than healthy children and adolescents. Data from a Canadian cohort of children with new-onset JIA (n= 164, data collection 2007-2012) were compared to Canadian Health Measures Survey (CHMS) data (n=4027, data collection 2007-2011). We compared 25-hydroxy vitamin D (25(OH)D) concentrations with measures of inflammation, vitamin D supplement use, milk intake, and season of birth. Mean 25(OH)D level was significantly higher in patients with JIA (79 ± 3.1 nmol/L) than in healthy controls (68 ± 1.8 nmol/L P <.05). Patients with JIA more often used vitamin D containing supplements (50% vs. 7%; P <.05). The prevalence of 25(OH)D deficiency (<30 nmol/L) was 6% for both groups. Children with JIA with 25(OH)D deficiency or insufficiency (<50 nmol/L) had higher C-reactive protein levels. Children with JIA were more often born in the fall and winter compared to healthy children. In contrast to earlier studies, we found vitamin D levels in Canadian children with JIA were higher compared to healthy children and associated with more frequent use of vitamin D supplements. Among children with JIA, low vitamin D levels were associated with indicators of greater inflammation.     

Threshold and non-threshold chemical carcinogens: A survey of the present regulatory landscape

For the proper regulation of a carcinogenic material it is necessary to fully understand its mode of action, and in particular whether it demonstrates a threshold of effect. This paper explores our present understanding of carcinogenicity and the mechanisms underlying the carcinogenic response. The concepts of genotoxic and non-genotoxic and threshold and non-threshold carcinogens are fully described. We provide summary tables of the types of cancer considered to be associated with exposure to a number of carcinogens and the available evidence relating to whether carcinogenicity occurs through a threshold or non-threshold mechanism. In light of these observations we consider how different regulatory bodies approach the question of chemical carcinogenesis, looking in particular at the definitions and methodologies used to derive Occupational Exposure Levels (OELs) for carcinogens. We conclude that unless proper differentiation is made between threshold and non-threshold carcinogens, inappropriate risk management measures may be put in place - and lead also to difficulties in translating carcinogenicity research findings into appropriate health policies. We recommend that clear differentiation between threshold and non-threshold carcinogens should be made by all expert groups and regulatory bodies dealing with carcinogen classification and risk assessment.