A Physical Model of the Intracranial System for the Study of the Mechanisms of the Cerebral Blood Flow Autoregulation

This paper introduces a novel physical model of the intracranial system, which was built with the specific purpose of gaining a better insight into the fundamental mechanisms involved in the cerebral circulation. Specifically, the phenomena of passive autoregulation of the blood flow and the variation of the intracranial compliance as a function of the mean intracranial pressure have been investigated. The physical model allows to go beyond state-of-the-art mathematical models that are often based on strong assumptions or simplifications on the physical mechanisms governing the cerebral circulation. Indeed, the physical model based on passive components was able to correctly replicate some fundamental mechanisms of the blood flow autoregulation. In particular, it allows to highlight the role of the venous outflow, which behaves as a Starling resistor. The physical model can be employed as a demonstrator for educational purpose and to test the behavior of shunts for the therapy of hydrocephalus

Activated ERK1/2 expression in glioblastoma multiforme and in peritumor tissue

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L'immagine medico-nucleare recettoriale guida la terapia del residuo post-chirurgico degli adenomi ipofisari non secernenti

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Expression of iNOS, CD163 and ARG-1 taken as M1 and M2 markers of microglial polarization in human glioblastoma and the surrounding normal parenchyma

Microglia and macrophages appear to be the most common cells in the GBM microenvironment. In the present study we investigated the status of macrophages/microglia activation in surgical specimens from 41 patients diagnosed with grade IV GBM. For each patient we analyzed both the center of tumor and the parenchyma surrounding the tumor. The specimens were stained for: i) IBA1, a 17-kDa EF hand protein specifically expressed in microglia/macrophages ii) CD163, a cell surface antigen associated with M2 phenotype; iii) iNOS, taken as a functional marker of M1 phenotype, and iv) ARG-I, taken as a functional marker of M2 phenotype. Staining was scored in a double-blinded score on a scale from 0 to 5. Our results suggest that CD163 expression is higher within the tumor than in surrounding periphery in both male and female patients; while iNOS is higher within the tumor in males, no significant difference was found for ARG-1. In addition, analyzing the data in TGCA database, we found that CD163 expression was significantly and inversely correlated with mean survival times, with average survival times ranging from 448 days in patients having low expression, to 319 in mid, and 353 in patients with high CD163 expressing tumors. In contrast, no significant association was found between survival time and ARG-1 or iNOS expression

Storms, hanged pirates, anemia, exsanguination: the contributions of Monro, Kellie and Abercrombie in understanding intracranial blood circulation

The so-called Monro-Kellie doctrine states that with an intact skull, the sum of the volume of the brain plus the cerebrospinal fluid volume plus the intracranial blood volume is constant. Therefore an increase in one should cause a reduction in one or both of the remaining two. The researcher who expressed the doctrine in such a way was indeed Harvey Cushing in 1925, during a lecture in Edinburgh. The original Monro-Kellie doctrine is the result of observations on autopsies and several animal experiments. What the original doctrine states is a dynamic explanation of the intracranial system, aimed at explaining how a pulsatile and continuous perfusion may occur in a closed-non-expandable and fully filled system. During each cardiac cycle the quantity of blood within the head must be the same: during the systole, the brain arteries dilate, and, in the mean time, a quantity of blood, equal to that which is dilating them, is passing out of the head through the veins. During the succeeding diastole, the quantity which dilated the brain arteries passes into the corresponding veins and, at the same time, as much passes from the sinuses out of the head, as enters into the head from the arteries situated between the heart and the head. Monro implicitly states that the blood coming out from the cerebral veins into the sinuses must be pulsatile and (almost) synchronous with the arteries. That is deeply different from the concept of a constant content of a rigid case, as expressed by Cushing

The intracranial system: A new interpretation of the Monro-Kellie doctrine

In this paper we have reported our experience in several years in whom we have studied the phenomena correlated with the intracranial pressure. We have started to study different types of animals during an experimental condition of intracranial hypertension; we have observed many different configurations in spontaneous pathologic&nbsp; humans, and, eventually, in last years we have passed to confirm our ideas modelling an intracranial system in a physical phantom made by a centrifugal pump, stainless steel for base, glass for the wall, elastic tube for the cerebrovascular tree and collapsible tubes for venous drainage.We have noted that there is some confusion about the so-called Monro-Kellie doctrine; the major part of the scientist believe in a sort of static interpretation given by the sum of the compartment which constitute the intracranial system (parenchyma, blood and cerebrospinal fluid). But we believe in a dynamic interpretation in which there is a constant balance between the arterial inflow and venous outflow during each cardiac cycle.In this paper we have focused on the results, obtained in the different preparations, animals, humans and in vitro, all confirming the assumption that there is no difference between arterial inflow and venous outflow.</p

Intracranial-pressure monitoring in traumatic brain injury

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Adult idiopathic occlusion of the foramina of Monro: diagnostic tools and therapy

BACKGROUND AND PURPOSE: The bilateral foramina of Monro occlusion is an extremely rare event in adults. To date, only six cases of adult hydrocephalus due to idiopatic obstruction of the bilateral foramina of Monro (including our patient) have been reported. METHODS: The authors describe the case of a 41-year-old man with a recent onset of motor hindrance which occurred specially while jumping or playing basketball, together with recent memory impairment, deceleration of thought, and asthenia. The patient was studied with fast spin echo (FSE) and steady-state free precession high-resolution 3D sequences (SSFP) together with a ventricular infusion test, and subsequently treated with endoscopic foraminoplasty. RESULTS: The presenting symptoms completely resolved. Follow-up magnetic resonance imaging (MRI) showed the patency of right Monro foramen, with gradually decreasing ventricular size and increase of subarachnoid spaces. CONCLUSIONS: These patients should be accurately studied before treatment. In fact, MRI has made it possible to know what a surgeon will exactly find on the operative field. In that way a correct surgical planning can be achieved

Pattern Electroretinograms and Visual Evoked Potentials in Idiopathic Intracranial Hypertension

A subclinical visual dysfunction can be detected by psycho-physical methods in early-stage papilledema associated with idiopathic intracranial hypertension (IIH). We recorded steady-state pattern electroretinograms (PERGs) and visual evoked potentials (VEPs) to sinusoidal gratings of variable spatial frequency [0.6,1.0,1.4, 2.2 and 4.8 cycles/degree (cpd)] in 18 patients with IIH and early papilledema and in 21 age-matched controls. Spatial frequency selective reductions in the mean PERG (at 1–4.8 cpd) and VEP (at 4.8 cpd) amplitudes were found in patients in comparison with controls. The response functions of amplitude versus spatial frequency of patients' PERG and VEP displayed a low-pass shape, whereas in normal subjects PERG and VEP functions showed a bandpass and a high-pass shape, respectively. PERG and VEP abnormalities were found in 14 (77.7%) and 10 (55.5%) out of 18 patients, respectively. Most of these abnormalities involved only selected spatial frequencies (1.4–4.8 cpd). These results indicate spatial-frequency-dependent functional losses on both PERG and VEP in early papilledema, and suggest a potential value of these responses for detecting subtle visual abnormalities in IIH

Hormonal therapy for fertility and huge meningioma: a purely random association?

Sexual hormones have been related to the growth of meningiomas, also due to the almost constant expression of hormonal receptors by tumoral cells. A case of a woman with previous history of multiple treatment for infertility, harboring a huge meningioma is here described. The tumor was surgically resected and the immunohistochemical examination revealed a high expression of progesterone receptors on tumoral cells surface. A putative role of past progesterone administration in the growth of meningioma has been hypothesized. Particular caution should be paid whenever adopting sexual hormonal therapy, especially for fertility. A radiological examination (ideally MRI) could be advised before starting therapy, in order to rule out any intracranial meningioma