Microwave scan and brain biomarkers to rule out intracranial hemorrhage: study protocol of a planned prospective study (MBI01)

Prediction of clinical progression in nervous system diseases: plasma glial fibrillary acidic protein (GFAP)

Glial fibrillary acidic protein (GFAP), an intracellular type III intermediate filament protein, provides structural support and maintains the mechanical integrity of astrocytes. It is predominantly found in the astrocytes which are the most abundant subtypes of glial cells in the brain and spinal cord. As a marker protein of astrocytes, GFAP may exert a variety of physiological effects in neurological diseases. For example, previous published literatures showed that autoimmune GFAP astrocytopathy is an inflammatory disease of the central nervous system (CNS). Moreover, the studies of GFAP in brain tumors mainly focus on the predictive value of tumor volume. Furthermore, using biomarkers in the early setting will lead to a simplified and standardized way to estimate the poor outcome in traumatic brain injury (TBI) and ischemic stroke. Recently, observational studies revealed that cerebrospinal fluid (CSF) GFAP, as a valuable potential diagnostic biomarker for neurosyphilis, had a sensitivity of 76.60% and specificity of 85.56%. The reason plasma GFAP could serve as a promising biomarker for diagnosis and prediction of Alzheimer's disease (AD) is that it effectively distinguished AD dementia from multiple neurodegenerative diseases and predicted the individual risk of AD progression. In addition, GFAP can be helpful in differentiating relapsing-remitting multiple sclerosis (RRMS) versus progressive MS (PMS). This review article aims to provide an overview of GFAP in the prediction of clinical progression in neuroinflammation, brain tumors, TBI, ischemic stroke, genetic disorders, neurodegeneration and other diseases in the CNS and to explore the potential therapeutic methods.

Complex Permittivity of Ex-Vivo Human, Bovine and Porcine Brain Tissues in the Microwave Frequency Range

Accurate knowledge about the dielectric properties of biological tissues in the microwave frequency range may lead to advancement of biomedical applications based on microwave technology. However, the published data are very scarce, especially for human brain tissues. The aim of this work was to measure and report the complex permittivity of brain white matter, grey matter and cerebellum. Complex permittivity was measured on human, bovine and porcine brain tissues in the microwave frequency range from 0.5 to 18 GHz using an open-ended coaxial probe. The results present a valuable addition to the available data on the brain tissue complex permittivity. Some noticeable variations between the results lead to several conclusions. Complex permittivity variation within the same tissue type of the individual species was comparable to interspecies variation. The difference was prominent between human brains obtained from autopsies, while bovine brains obtained from healthy animals showed very similar complex permittivity. We hypothesize that the difference might have been caused by the basic pathologies of the patients, where the associated therapies could have affected the brain water content. We also examined the effect of excised tissue degradation on its complex permittivity over the course of three days, and the results suggest the gradual dehydration of the samples.