Hemodynamics of Prefrontal Cortex in Ornithine Transcarbamylase Deficiency: A Twin Case Study

Review of Applications of Near-Infrared Spectroscopy in Two Rare Disorders with Executive and Neurological Dysfunction: UCD and PKU

Studying rare diseases, particularly those with neurological dysfunction, is a challenge to researchers and healthcare professionals due to their complexity and small population with geographical dispersion. Universal and standardized biomarkers generated by tools such as functional neuroimaging have been forged to collect baseline data as well as treatment effects. However, the cost and heavily infrastructural requirement of those technologies have substantially limited their availability. Thus, developing non-invasive, portable, and inexpensive modalities has become a major focus for both researchers and clinicians. When considering neurological disorders and diseases with executive dysfunction, EEG is the most convenient tool to obtain biomarkers which can correlate the objective severity and clinical observation of these conditions. However, studies have also shown that EEG biomarkers and clinical observations alone are not sensitive enough since not all the patients present classical phenotypical features or EEG evidence of dysfunction. This article reviews disorders, including two rare disorders with neurological dysfunction and the usefulness of functional near-infrared spectroscopy (fNIRS) as a non-invasive optical modality to obtain hemodynamic biomarkers of diseases and for screening and monitoring the disease.

The nano delivery systems and applications of mRNA

The current COVID-19 epidemic has greatly accelerated the application of mRNA technology to our real world, and during this battle mRNA has proven it's unique advantages compared to traditional biopharmaceutical and vaccine technology. In order to overcome mRNA instability in human physiological environments, mRNA chemical modifications and nano delivery systems are two key factors for their in vivo applications. In this review, we would like to summarize the challenges for clinical translation of mRNA-based therapeutics, with an emphasis on recent advances in innovative materials and delivery strategies. The nano delivery systems include lipid delivery systems (lipid nanoparticles and liposomes), polymer complexes, micelles, cationic peptides and so on. The similarities and differences of lipid nanoparticles and liposomes are also discussed. In addition, this review also present the applications of mRNA to other areas than COVID-19 vaccine, such as infectious diseases, tumors, and cardiovascular disease, for which a variety of candidate vaccines or drugs have entered clinical trials. Furthermore, mRNA was found that it might be used to treat some genetic disease, overcome the immaturity of the immune system due to the small fetal size in utero, treat some neurological diseases that are difficult to be treated surgically, even be used in advancing the translation of iPSC technology et al. In short, mRNA has a wide range of applications, and its era has just begun.

Neuromonitoring in Rare Disorders of Metabolism

Inborn errors of metabolism (IEM) are a unique class of genetic diseases due to mutations in genes involved in key metabolic pathways. The combined incidence of IEM has been estimated to be as high as 1:1000. Urea Cycle disorders (UCD), one class of IEM, can present with cerebral edema and represent a possible target to explore the utility of different neuromonitoring techniques during an hyperammonemic crisis. The last two decades have brought advances in the early identification and comprehensive management of UCD, including further understanding of neuroimaging patterns associated with neurocognitive function. Nonetheless, very important questions remain about the potential acute neurotoxic effects of hyperammonemia to better understand how to treat and prevent secondary brain injury. In this review, we describe existing neuromonitoring techniques that have been used in rare metabolic disorders to assess and allow amelioration of ongoing brain injury. Directions of future research should be focused on identifying new diagnostic approaches in the management of metabolic crises to optimize care and reduce long term morbidity and mortality in patients with IEM.