Ioannis Magras

Primary extracerebral meningeal glioblastoma: clinical and pathological analysis.

Primary meningeal gliomas are uncommon tumors in the subarachnoid space, their primary characteristic being the absence of any obvious connection to the brain parenchyma. Rarely, they are quite malignant and assume a bulky, well circumscribed appearance rendering the differential diagnosis from other CNS neoplasms difficult. A 53-year-old man presented with a history of persistent headaches and left sided weakness. Magnetic resonance imaging revealed a temporoparietal mass attached to the dura that strongly resembled a meningioma. At surgery, the outer layer of the dura mater was intact and there was a clear brain-tumor interface without obvious pial disruption. Histological examination showed a biphasic pattern consisting of benign connective tissue intermingled with bundles of what seemed to be a glioblastoma. The mass demonstrated strong positivity for GFAP and the MIB labeling index focally exceeded 20%. The tumor was identified as a primary meningeal glioblastoma. The patient was disease-free for 42 months, after which he developed a recurrence for which he was re-operated. This time, the pathological findings of the tumor were those of a typical glioblastoma multiforme. We discuss the origin of the initial neoplasm and also the differential diagnosis that needs to include meningioma, aggressive glioblastoma infiltrating the dura and a recently recognized bimorphic CNS tumor: the desmoplastic glioblastoma.

Lasting bilateral mydriasis after traumatic brain injury may not always be a lost case

Background: Lasting bilateral mydriasis and absence of pupillary light reflex following severe traumatic brain injury (TBI) are considered signs of irreversible brainstem damage and have been strongly associated with poor outcome. Case Description: A young female patient presented with severe TBI, contusions, and diffuse brain edema. She was initially treated medically, but developed delayed secondary refractory intracranial hypertension and bilaterally dilated, non-reactive pupils for 12 h. Wide decompressive craniectomy and dural incisions were performed. The patient presented gradual improvement in her clinical condition [Glasgow Coma Scale (GCS) 13/15]. Delayed recurring infections lead to the patients death due to sepsis after 3 months. Conclusion: In light of recent studies, lasting bilateral mydriasis may not always be considered a decisive factor for non-escalation of treatment, as variability among TBI patients and outcomes has been demonstrated. Wide decompressive craniectomy is viable for controlling refractory intracranial hypertension in hemodynamically stable patients.

State of the Art and Future Prospects of Nanotechnologies in the Field of Brain-Computer Interfaces

Neuroprosthetic control by individuals suffering from tetraplegia has already been demonstrated using implanted microelectrode arrays over the patients’ motor cortex. Based on the state of the art of such micro & nano-scale technologies, we review current trends and future prospects for the implementation of nanotechnologies in the field of Brain- Computer Interfaces (BCIs), with brief mention of current clinical applications. Micro- and Nano-Electromechanical Systems (MEMS, NEMS) and micro-Electrocorticography now belong to the mainstay of neurophysiology, producing promising results in BCI applications, neurophysiological recordings and research. The miniaturization of recording and stimulation systems and the improvement of reliability and durability, decrease of neural tissue reactivity to implants, as well as increased fidelity of said systems are the current foci of this technology. Novel concepts have also begun to emerge such as nanoscale integrated circuits that communicate with the macroscopic environment, neuronal pattern nano-promotion, multiple biosensors that have been “wired” with piezoelectric nanomechanical resonators, or even “neural dust” consisting of 10-100μm scale independent floating low-powered sensors. Problems that such technologies have to bypass include a minimum size threshold and the increase in power to maintain a high signal-to-noiseratio. Physiological matters such as immunological reactions, neurogloia or neuronal population loss should also be taken into consideration. Progress in scaling down of injectable interfaces to the muscles and peripheral nerves is expected to result in less invasive BCI-controlled actuators (neuroprosthetics in the micro and nano scale). The state-of-the-art of current microtechnologies demonstrate a maturing level of clinical relevance and promising results in terms of neural recording and stimulation. New MEMS and NEMS fabrication techniques and novel design and application concepts hold promise to address current problems with these technologies and lead to less invasive, longer lasting and more reliable BCI systems in the near future.