3,354 research outputs found
Surgical Treatment of Benign Spinal Cord Tumors
Benign spinal cord tumors (SCTs) are uncommon neoplasms that can arise within or adjacent to the spinal cord. Depending on their anatomical location, benign SCTs can be categorized as intramedullary, intradural-extramedullary, and extradural. The three most common benign SCTs are meningioma, nerve sheath tumors, and ependymoma. Both meningioma and nerve sheath tumors develop in the intradural-extramedullary compartment, while ependymoma occurs in the intramedullary space. Spinal meningiomas derive from arachnoidal cells and most commonly occur within the thoracic segment of the spine. Nerve sheath tumors, including schwannomas and neurofibromas, are closely associated with spinal nerves. Half of the spinal cord ependymomas arise in the lumbosacral segment or the filum terminale. Surgical treatment of large or symptomatic benign SCTs concentrates on total or subtotal resection of the tumors, which should be cautiously individualized based on the tumor location and histopathology. A curable complete resection should be achieved if possible while preserving the nervous function of the spinal cord and minimizing potential complications. Thoracic spinal roots may be sacrificed to acquire a total resection, yet cervical and lumbar nerve roots should be preserved prudently. Due to the vulnerable and complex anatomic nature of the spinal cord, maximal resection of the tumors can be achieved with the aid of appropriate intraoperative neural monitoring and meanwhile preserve nervous function
Editorial: Natural products and brain energy metabolism: Astrocytes in neurodegenerative diseases Volume II
A New Approach to Black Hole Quasinormal Modes: A Review of the Asymptotic Iteration Method
We discuss an approach to obtaining black hole quasinormal modes (QNMs) using
the asymptotic iteration method (AIM), initially developed to solve second
order ordinary differential equations. We introduce the standard version of
this method and present an improvement more suitable for numerical
implementation. We demonstrate that the AIM can be used to find radial QNMs for
Schwarzschild, Reissner-Nordstrom (RN) and Kerr black holes in a unified way.
An advantage of the AIM over the standard continued fraction method (CFM) is
that for differential equations with more than three regular singular points
Gaussian eliminations are not required. However, the convergence of the AIM
depends on the location of the radial or angular position, choosing the best
such position in general remains an open problem. This review presents for the
first time the spin 0, 1/2 & 2 QNMs of a Kerr black hole and the gravitational
and electromagnetic QNMs of the RN black hole calculated via the AIM, and
confirms results previously obtained using the CFM. We also presents some new
results comparing the AIM to the WKB method. Finally we emphasize that the AIM
is well suited to higher dimensional generalizations and we give an example of
doubly rotating black holes.Comment: RevTeX 4-1, various tables and figures; vz. 2 extra comments and
references added; to appear in Advances in Mathematical Physic
Immunotherapy for Glioblastomas
Glioblastoma (GBM), a WHO grade IV brain tumor, is an aggressive tumor with poor prognosis; even with current standard care of triple therapy, consisting of surgical resection, chemo and radiation therapy, the patients’ median survival time is only approximately 15 months. Recent practice shows that immunotherapy made some progress in some other solid tumors, like melanoma or non-small cell lung cancer. This chapter is going to review some advances in immunotherapy for GBM
Neuroendocrine pathogenesis of perimenopausal depression
With the development of social economics and the increase of working pressure, more and more women are suffering from long-term serious stress and showing symptoms of perimenopausal depression (PMD). The incidence rate of PMD is increasing, and the physical and mental health are seriously affected. However, due to the lack of accurate knowledge of pathophysiology, its diagnosis and treatment cannot be accurately executed. By consulting the relevant literature in recent years, this paper elaborates the neuroendocrine mechanism of perimenopausal depression from the aspects of epigenetic changes, monoamine neurotransmitter and receptor hypothesis, glial cell-induced neuroinflammation, estrogen receptor, interaction between HPA axis and HPG axis, and micro-organism-brain gut axis. The purpose is to probe into new ways of treatment of PMD by providing new knowledge about the neuroendocrine mechanism and treatment of PMD
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