Relapsing Polychondritis with Central Nervous System Involvement: Experience of Three Different Cases in a Single Center

Relapsing polychondritis (RP) is an autoimmune disorder characterized by inflammation in cartilaginous structures including the ears, noses, peripheral joints, and tracheobronchial tree. It rarely involves the central nervous system (CNS) but diagnosis of CNS complication of RP is challenging because it can present with varying clinical features. Herein we report 3 cases of relapsing polychondritis involving CNS with distinct manifestations and clinical courses. The first patient presented with rhombencephalitis resulting in brain edema and death. The second patient had acute cognitive dysfunction due to limbic encephalitis. He was treated with steroid pulse therapy and recovered without sequelae. The third patient suffered aseptic meningitis that presented as dementia, which was refractory to steroid and immune suppressive agents. We also reviewed literature on CNS complications of RP.     

Autophagy in osteoarthritis

Osteoarthritis is characterized by continuous degeneration of articular cartilage resulting in disability. The death of chondrocytes and the loss of the extracellular matrix are the central peculiarities in cartilage degeneration during osteoarthritis pathogenesis. Autophagy is an essential cellular homeostasis mechanism whereby cellular organelles and macromolecules are recycled to maintain cellular metabolism. Autophagy is reported to be cytoprotective effects for articular cartilage, and osteoarthritis is associated with decreased autophagy. While autophagy is known to be cytoprotective to chondrocytes, its role may vary with differing stages and models of osteoarthritis. Therefore, more in-depth studies on autophagy are needed to determine its impact on cell survival and death in articular cartilage under various in vitro and in vivo conditions. Application of autophagy on osteoarthritis therapeutics will be possible after a profound understanding is established on the role of autophagy in osteoarthritis pathogenesis.     

Quantitative assessment of global cerebral metabolic rate of oxygen (CMRO2) in neonates using MRI

The cerebral metabolic rate of oxygen (CMRO₂) is the rate of oxygen consumption by the brain, and is thought to be a direct index of energy homeostasis and brain health. However, in vivo measurement of CMRO₂ is challenging, in particular for the neonatal population, in whom conventional radiotracer methods are not applicable because of safety concerns. In this study, we propose a method to quantify global CMRO₂ in neonates based on arteriovenous differences in oxygen content, and employ separate measurements of oxygenation and cerebral blood flow (CBF) parameters. Specifically, arterial and venous oxygenation levels were determined with pulse oximetry and the novel T₂ relaxation under spin tagging (TRUST) MRI, respectively. Global CBF was measured with phase contrast (PC) flow velocity MRI. The proposed method was implemented on a standard 3‐T MRI scanner without the need for any exogenous tracers, and the total scan duration was less than 5 min. We demonstrated the feasibility of this method in 12 healthy neonates within an age range of 35–42 gestational weeks. CMRO₂ values were successfully obtained from 10 neonates. It was found that the average CMRO₂ in this age range was 38.3 ± 17.7 µmol/100 g/min and was positively correlated with age (p = 0.007; slope, 5.2 µmol/100 g/min per week), although the highest CMRO₂ value in this age range was still less than half of the adult level. Test–retest studies showed a coefficient of variation of 5.8 ± 2.2% between repeated CMRO₂ measurements. In addition, given the highly variable blood flow velocity within this age range, it is recommended that the TRUST labeling thickness and position should be determined on a subject‐by‐subject basis, and an automatic algorithm was developed for this purpose. Although this method provides a global CMRO₂ measure only, the clinical significance of an energy consumption marker and the convenience of this technique may make it a useful tool in the functional assessment of the neonatal population. Copyright © 2014 John Wiley & Sons, Ltd.