A new method for the early diagnosis of brain edema/brain swelling. An experimental study in rabbits

Kostopoulos, V.; Douzinas, E.; Kypriades, E.M.; Pappas, Y.Z.

doi:10.1016/j.jbiomech.2005.11.001

Cited by 3 publications

(2 citation statements)

References 17 publications

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“…This model was chosen due to the inaccessibility of human tissue and is appropriate for our experiments because the corticosteroid profile resembles that of humans. In addition, this model has been used for a variety of in vivo (18), CSF and intracranial pressure studies (19)(20)(21)(22)(23)(24).…”

mentioning

confidence: 99%

Corticosteroids, 11β‐Hydroxysteroid Dehydrogenase Isozymes and the Rabbit Choroid Plexus

Sinclair¹,

Onyimba²,

Khosla³

et al. 2007

J Neuroendocrinology

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The epithelial cells of the choroid plexus (CP) are responsible for cerebrospinal fluid (CSF) secretion into the ventricles of the brain. The balance between CSF production and drainage, in part, facilitates a normal intracranial pressure. The secretion of Na(+) and anions by the CP creates an osmotic gradient driving water into the ventricles. This is opposite to classical Na(+) transporting tissues, such as the kidney, where Na(+) and water reabsorption is mediated by 11beta-hydroxysteroid dehydrogenase type 2 that protects the mineralocorticoid receptor by abrogating active cortisol to inactive cortisone. In the human ocular ciliary epithelium, Na(+) and water secretion is dependent on a novel mediator of ciliary epithelial Na(+) transport, 11beta-HSD type 1 (11beta-HSD1), that generates intraocular cortisol. In a mechanism analogous to that of the embryologically related ocular ciliary epithelium, we propose that autocrine regulation of intracranial cortisol is dependent on 11beta-HSD1 expression in the CP epithelial cells. By conducting immunolocalisation studies on brains from New Zealand White Albino rabbits, we defined the expression of 11beta-HSD1 in the secretory CP epithelial cells. Enzyme assays performed on intact rabbit CP whole tissue explants confirmed predominant 11beta-HSD1 activity, generating cortisol that was inhibited by glycyrrhetinic acid (an 11beta-HSD inhibitor). Using the real time-polymerase chain reaction, rabbit CP tissue was found to express levels of 11beta-HSD1, glucocorticoid receptor alpha and serum and glucocorticoid-regulated kinase 1 mRNA comparable to that expressed in rabbit ocular ciliary body, thereby highlighting the similarity between these two tissues. Furthermore, an enzyme-linked immunosorbent assay of rabbit CSF revealed a median cortisol concentration of 1.7 nmol/l (range 1.4-4.3 nmol/l, n = 9). Our data have identified a functional 11beta-HSD1 within the CP, mediating intracranial cortisol bioavailability. Expression of 11beta-HSD1 may be fundamental in the regulation of CSF secretion and the local generation of cortisol may represent a pathophysiological mechanism underlying cortisol-dependent neuroendocrine diseases.

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confidence: 99%

Corticosteroids, 11β‐Hydroxysteroid Dehydrogenase Isozymes and the Rabbit Choroid Plexus

Sinclair¹,

Onyimba²,

Khosla³

et al. 2007

J Neuroendocrinology

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“…The (acoustic/vibration) natural resonance frequency (NRF) spectrum and its modal damping characteristics were successfully used to estimate the ICP in an experimental study in rabbits [ 125 ]. An excellent correlation was observed between the best NRF and the inserted CSF volume (r 2 = 0.96) as a surrogate for the ICP.…”

Section: Approaches Of Non-invasive Measurementsmentioning

confidence: 99%

Non-Invasive Intracranial Pressure Monitoring

Müller

Henkes

Gounis³

et al. 2023

JCM

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(1) Background: Intracranial pressure (ICP) monitoring plays a key role in the treatment of patients in intensive care units, as well as during long-term surgeries and interventions. The gold standard is invasive measurement and monitoring via ventricular drainage or a parenchymal probe. In recent decades, numerous methods for non-invasive measurement have been evaluated but none have become established in routine clinical practice. The aim of this study was to reflect on the current state of research and shed light on relevant techniques for future clinical application. (2) Methods: We performed a PubMed search for “non-invasive AND ICP AND (measurement OR monitoring)” and identified 306 results. On the basis of these search results, we conducted an in-depth source analysis to identify additional methods. Studies were analyzed for design, patient type (e.g., infants, adults, and shunt patients), statistical evaluation (correlation, accuracy, and reliability), number of included measurements, and statistical assessment of accuracy and reliability. (3) Results: MRI-ICP and two-depth Doppler showed the most potential (and were the most complex methods). Tympanic membrane temperature, diffuse correlation spectroscopy, natural resonance frequency, and retinal vein approaches were also promising. (4) Conclusions: To date, no convincing evidence supports the use of a particular method for non-invasive intracranial pressure measurement. However, many new approaches are under development.

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Wavelet Analysis of Head Acceleration Response Under Dirac Excitation for Early Oedema Detection

Kostopoulos

Λούτας

Derdas

et al. 2008

Journal of Biomechanical Engineering

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The present work deals with the application of an innovative in-house developed wavelet-based methodology for the analysis of the acceleration responses of a human head complex model as a simulated diffused oedema progresses. The human head complex has been modeled as a structure consisting of three confocal prolate spheroids, whereas the three defined regions by the system of spheroids, from the outside to the inside, represent the scull, the region of cerebrospinal fluid, and the brain tissue. A Dirac-like pulse has been used to excite the human head complex model and the acceleration response of the system has been calculated and analyzed via the wavelet-based methodology. For the purpose of the present analysis, a wave propagation commercial finite element code, LS-DYNA 3D, has been used. The progressive diffused oedema was modeled via consecutive increases in brain volume accompanied by a decrease in brain density. It was shown that even a small increase in brain volume (at the level of 0.5%) can be identified by the effect it has on the vibration characteristics of the human head complex. More precisely, it was found that for some of the wavelet decomposition levels, the energy content changes monotonically as the brain volume increases, thus providing a useful index of monitoring an oncoming brain oedema before any brain damage appears due to uncontrolled intracranial hypertension. For the purpose of the present work and for the levels of brain volume increase considered in the present analysis, no pressure increase was assumed into the cranial vault and, associatively, no brain compliance variation.

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A new method for the early diagnosis of brain edema/brain swelling. An experimental study in rabbits

Cited by 3 publications

References 17 publications

Corticosteroids, 11β‐Hydroxysteroid Dehydrogenase Isozymes and the Rabbit Choroid Plexus

Corticosteroids, 11β‐Hydroxysteroid Dehydrogenase Isozymes and the Rabbit Choroid Plexus

Non-Invasive Intracranial Pressure Monitoring

Wavelet Analysis of Head Acceleration Response Under Dirac Excitation for Early Oedema Detection

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