Drainage Of Brain Research Articles

Original Research: Feasibility and safety of two surgical techniques for the development of an animal model of jugular vein occlusion.

To date, no studies have explored the effect of abnormal cerebral venous circulation on brain disorders, whereas many studies have investigated neurodegenerative brain anomalies associated with arterial diseases. The aim of our study was to demonstrate the feasibility of different surgical techniques to induce venous obstruction of cerebral brain drainage. Six C57/black mice underwent bilateral occlusion of the external jugular vein (group EJV), six underwent bilateral occlusion of the internal jugular vein (group IJV), and six underwent bilateral occlusion of both the EJV and the IJV (group EJV/IJV). Within each group, the interruption of blood flow was obtained via monopolar electro-coagulation (ME) in three mice and via surgical ligation (SL) in the remaining three mice. A "sham group" of two mice was used as the control. High-frequency ultrasound (HFUS) was used to detect the absence of blood flow in the examined vessel. The ME procedure led to successful results in two of nine (22%) mice, one in the EJV group, one in the EJV/IJV group, and zero in the IJV group, and 4 of 18 (22%) mice when considering individual veins (i.e., total number of EJVs and IJVs occluded). The SL procedure was successful in two of three (67%) mice in the EJV group, in three of three (100%) mice in the IJV and in three of four (75%) mice in the EJV/IJV group. Therefore, the overall success rate was 8/10 (80%) when considering mice, and 20/26 (77%) when considering individual veins. The monopolar electro-coagulation method exhibited a high mortality due to cardiorespiratory arrest, while the results of the bilateral surgical ligation of EJVs and IJVs show that it is technically feasible and safe.

Utilizing IT to Enhance Knowledge Sharing for School Educators in Developing Countries

AbstractKnowledge has been considered a critical factor for any organization's survival however its retention and utilization has remained a challenge to many organizations in developing countries education institutions inclusive. These challenges are mostly attributed to the fact that knowledgeable employees often leave organizations before they could share their valuable knowledge and expertise. In schools of developing countries in particular, educators struggle for subsistence and many leave to seek for greener pastures. Such exodus of educators has led to knowledge loss and has widened the knowledge gap between the schools for the rich and those for the poor. This has been worse especially in the most challenging subjects like Science and Mathematics. Closing this gap, schools need to depend on the knowledge of other experienced educators that are still in the Education system in order to enhance the capabilities of those that are inexperienced. For this reason, leveraging Information Technology (IT) to facilitate the sharing of knowledge, communicate ideas, exchange views and information between educators is paramount. There is a need for schools in developing countries’ to have guidelines of how IT could be utilized for knowledge sharing. The major objective of this paper is therefore to report on the utilization of IT to enhance Knowledge Sharing (KS) among educators in developing countries taking a case of South Africa. The Social Exchange Theory (SET), Theory of Reasoned Action (TRA) and The Unified Theory of Acceptance and Use of Technology (UTAUT) were used to design a conceptual framework for the study. Data was collected from secondary schools’ educators in Tshwane South district of South Africa and was analyzed quantitatively. The results indicated that, knower's attitude is a high significant contributing factor whereas dependence of the knower is the least and insignificant in the utilization of IT to enhance knowledge sharing. Practically, this study could be leveraged by schools and governments to entrench tacit knowledge and to address the brain drainage associated with the continuous exodus of the skilled and experienced educators. Further still, the designed framework could be used by Information Systems scholars to extend research of knowledge sharing and management.

Lymphatic drainage of the brain and CSF: Relevance to neuroimmunology and Alzheimer's disease

Lymphatic drainage of the brain and CSF: Relevance to neuroimmunology and Alzheimer's disease

Complications of Sigmoid Sinus Transvenous Occlusion for the Endovascular Treatment of Dural Arteriovenous Shunts with Emphasis on Inner Ear Dysfunction

Embolization of cranial dural sinus arteriovenous fistulae with transvenous occlusion of the involved sinuses is an established strategy when the collateral brain drainage allows it. We aimed to investigate the frequency and types of complications after endovascular occlusion of the sigmoid sinus. From our database, we detected 52 endovascularly treated consecutive cases of cranial dural arteriovenous shunts involving the sigmoid sinus. The cases treated through the transvenous approach alone or combined with the transarterial one were analyzed retrospectively. Previously reported series and cases were reviewed and critically analyzed. In 15 cases, a transvenous approach was used and in 4 combined a transvenous approach with a transarterial approach. Two patients (13.3%) both treated with the transvenous approach alone presented postoperatively with vertigo and hearing loss. In the first case, the sinus occlusion involved the whole sigmoid sinus, whereas in the second case the occlusion was restricted to a parallel channel posteriorly to the proximal segment of the sigmoid sinus. Magnetic resonance imaging and ear, nose, and throat investigations failed to elucidate the cause and pathomechanism of these symptoms. No other complications occurred. Although the transvenous occlusion of the sigmoid sinus generally is a safe therapeutic option for the treatment of dural arteriovenous fistulae, inner ear dysfunction is still a possible complication. The combined analysis of the reported and our cases did not allow a plausible explanation of this complication and its pathomechanism remains obscure.

An anatomy-based lumped parameter model of cerebrospinal venous circulation: can an extracranial anatomical change impact intracranial hemodynamics?

BackgroundThe relationship between extracranial venous system abnormalities and central nervous system disorders has been recently theorized. In this paper we delve into this hypothesis by modeling the venous drainage in brain and spinal column areas and simulating the intracranial flow changes due to extracranial morphological stenoses.MethodsA lumped parameter model of the cerebro-spinal venous drainage was created based on anatomical knowledge and vessels diameters and lengths taken from literature. Each vein was modeled as a hydraulic resistance, calculated through Poiseuille’s law. The inputs of the model were arterial flow rates of the intracranial, vertebral and lumbar districts. The effects of the obstruction of the main venous outflows were simulated. A database comprising 112 Multiple Sclerosis patients (Male/Female = 42/70; median age ± standard deviation = 43.7 ± 10.5 years) was retrospectively analyzed.ResultsThe flow rate of the main veins estimated with the model was similar to the measures of 21 healthy controls (Male/Female = 10/11; mean age ± standard deviation = 31 ± 11 years), obtained with a 1.5 T Magnetic Resonance scanner. The intracranial reflux topography predicted with the model in cases of internal jugular vein diameter reduction was similar to those observed in the patients with internal jugular vein obstacles.ConclusionsThe proposed model can predict physiological and pathological behaviors with good fidelity. Despite the simplifications introduced in cerebrospinal venous circulation modeling, the key anatomical feature of the lumped parameter model allowed for a detailed analysis of the consequences of extracranial venous impairments on intracranial pressure and hemodynamics.Electronic supplementary materialThe online version of this article (doi:10.1186/s12883-015-0352-y) contains supplementary material, which is available to authorized users.

Toxicokinetics of perfluoroalkyl carboxylic acids with different carbon chain lengths in mice and humans.

Perfluoroalkyl carboxylic acids (PFCAs) consist of analogs with various carbon chain lengths. Their toxicokinetics have remained unexplored except in the case of perfluorooctanoic acid (8 carbon chemicals). This study aimed to investigate the toxicokinetics of PFCAs with six to fourteen carbon atoms (C6 to C14) in mice and humans. We applied a two-compartment model to mice administered PFCAs intravenously or by gavage. The time courses of the serum concentration and tissue distribution and elimination were evaluated for 24 hours after treatment. For human samples, urine from healthy volunteers, bile from patients who underwent biliary drainage, and cerebral spinal fluid (CSF) from brain drainage were collected. The mouse experiment showed that short-chained PFCAs (C6 and C7) were rapidly eliminated in the urine, whereas long-chain PFCAs (C8 to C14) accumulated in the liver and were excreted slowly in feces. Urinary clearance of PFCAs in humans also decreased with increasing alkyl chain lengths, while biliary clearances increased. C9 to C10 had the smallest total clearance for both mice and humans. However, disparities existed in the magnitude of the total clearance between mice and humans. A slightly higher partition ratio (brain/serum) was observed for long-chained PFCAs in mice, but this was not observed in the corresponding partition ratio in humans (CSF/serum). The large sequestration volumes of PFCAs in the liver seem to be attributable to the liver's large binding capacity in both species. This will be useful in evaluating PFCA bioaccumulation in other species.

Lymphatic drainage of the brain in extreme arterial hypertension

In the experiment on rabbits were presents, that experimental arterial hypertension didn’t led to functional failure of lymphatic drainage of brain. On the background of beta-blocker obzidan use failure liquor outflow from brain took place.

More Canadian Brain Drainage

More Canadian Brain Drainage

More Canadian Brain Drainage

More Canadian Brain Drainage

Endocranial Occipito‐Temporal Anatomy of SD‐1219 from the Neandertal El Sidrón Site (Asturias, Spain)

We addressed the brain drainage system as inferred by the endocranial morphology of the occipito-temporal region of the El Sidrón Neandertal specimen SD-1219. Morphological details of the endocranial surface and its anatomical implications were analyzed for the reconstruction of the dural sinus drainage pattern and its comparison with Neandertals and other hominids. The specimen SD-1219 shows a pattern in which the superior sagittal sinus goes into the right transverse sinus. Comparative analyses with a large sample of fossil hominids reveal a pattern of the SD-1219 fossil that is typical for Neandertals. The analysis of the proportions of the occipital lobes prints within the occipital fossae reveals that the left occipital pole projects toward the right. This possibly indicates brain asymmetry (petalia) in this Neandertal individual, similar to that observed in some modern human brains. Conversely, no such asymmetry was observed in the cerebellar fossae. A particular feature of this fossil is the presence of two crests, located at the middle of the left cerebellar fossa that can be related to either an imprinting of a cerebellar fissure or some bone response to mechanical influence on internal bone surface morphology during cerebellar development. Specific aspects of the paleoneurology of Neandertals are discussed. Further quantitative studies on the endocranial morphology of the occipito-temporal and -mastoid region will shed light on the paleoneurological significance of this important anatomical region for the understanding of human evolution.

Patient Positioning and Ultrasound Guidance Are Important in Bilateral Cannulation of Internal Jugular Veins

To the Editor:— We congratulate Stocchetti et al. 1on their interesting case report and the favorable outcome of the patient. We agree with the authors that bilateral cannulation of internal jugular veins may worsen intracranial hypertension. Nevertheless, we wish to make some comments:For internal jugular vein cannulation, their patient’s head and torso were placed in a flat position, and the head was even slightly rotated. All these procedures are known to increase intracranial pressure in patients with reduced intracranial compliance. 2In the context of increased intracranial pressure, we wonder why the internal jugular vein route was preferred for the insertion of the 8-French introducer and Swan-Ganz catheter to the subclavian or external jugular vein route.In our opinion, Doppler or B-mode ultrasound guidance should always be used in these patients. Recently, we were able to demonstrate the safe cannulation even of the internal jugular veins in patients with reduced intracranial compliance under Doppler guidance without the need for change in body position. 3Following the arguments of Stocchetti et al. that the introducer itself was responsible for the obstructed cerebral venous drainage, a B-mode ultrasound image of the left internal jugular vein should have shown a small-sized vessel. With regard to the high thrombogenicity of large-bore catheters in small-sized veins, another access route would have been preferred. 4In this context, we refer to a fatal incident of intracranial hypertension we encountered after tracheostomy. 5During neck extension, the patient experienced brain herniation due to obstruction of the accessory brain drainage pathway (vertebral venous plexus) in the context of unrecognized bilateral internal jugular vein obstruction (left: thrombosis after central venous cannulation; right: hypoplastic vein).Blood drains from the brain by two major routes: the internal jugular veins and the vertebral venous plexus. 6,7Valdueza et al. 8have shown that predominance of the jugular veins in cerebrovenous drainage is limited to the supine position. When outflow through the internal jugular veins is compromised, the vertebral system becomes the major channel for blood leaving the cranium. 6Various clinical implications, such as bilateral neck dissection, or metastatic spread of tumors, including the controversies about head positioning in increased intracranial pressure, underline the importance of a postural influence on cerebrovenous drainage. 8In patients at risk, such as patients with reduced intracranial compliance, central venous access procedures should be performed under ultrasound guidance. 3

Dural Sinus Malformations (DSM) with Giant Lakes, in Neonates and Infants

Abstract: Background and Purpose. Dural Arteriovenous Shunt (DAVS) in children include Dural sinus malformation (DSM), infantile and adult types. They are rare and seldom reported. Our purpose was to highlight the angiographic features of the DSM sub group for prognosis of clinical evolution and outcome and to lay guidelines for management. From a dedicated neurovascular data bank, there were 52 cases of arteriovenous dural shunts in children from 1985 to 2003. Of these, there were 30 patients with DSM, which we analysed the various angioarchitecture, presentation and neurological outcome. Children clinical status was evaluated and scored at admission and follow up. Results. There was an overall male dominance of 2:1. Antenatal diagnosis was obtained in 8/30 (26.7%) cases. Mean age of diagnosis was 5 months. Mean age at first consultation was 8.7 months. No patient was diagnosed during childhood. The most common clinical presentations were macrocrania 76.7%, seizures 23.3% and mental retardation 23.3%. In 14/30 (35.7%) of the patients, the therapeutic decision was to manage conservatively; in 5/14 (30.7%) with predictable favourable evolution and in 9/14 (64.3%) with irreversible poor neurological outcome. In the remaining 16/30 (53.3%) patients, endovascular treatment was performed. In 12/16 (75.0%) patients the neurological outcome was good, 3/16 (18.8%) patients had unfavourable evolution despite embolization. There was no morbidity mortality related to the procedures themselves. 1/16 (6.3%) patient was lost to follow-up. Overall 12/29 (45.8%) patients had an unfavourable neurological outcome with 11 patients dead and 1 with severe neurological deficit. In the surviving group of children, 17/18 (94.4%) have a good neurological outcome; in 10/18 (55.5%) the lesion is morphologically excluded. Conclusion. DSM is rare disease with high mortality. They usually proceed to either total or partial spontaneous thrombosis before the age of 2 thus compromising normal cerebral venous drainage. DSM away from the torcular, good cavernous sinus, cavernous capture of sylvian veins, absence of pial veins, straight sinus or superior sagital sinus (SSS) reflux and absence of jugular bulb dysmaturation represent factors of good prognosis. Such patients will highly benefit for endovascular treatment. In partial endovascular approach the aim being is to separate the brain drainage from DSM drainage. This will be achieved by the transarterial approach to the associated mural arterio-venous shunts (AVS) and by disconnecting the pial reflux by transvenous route.

Health Risks Associated with Inhaled Nasal Toxicants

Health risks of inhaled nasal toxicants were reviewed with emphasis on chemically induced nasal lesions in humans, sensory irritation, olfactory and trigeminal nerve toxicity, nasal immunopathology and carcino-genesis, nasal responses to chemical mixtures, in vitro models, and nasal dosimetry- and metabolism-based extrapolation of nasal data in animals to humans. Conspicuous findings in humans are the effects of outdoor air pollution on the nasal mucosa, and tobacco smoking as a risk factor for sinonasal squamous cell carcinoma. Objective methods in humans to discriminate between sensory irritation and olfactory stimulation and between adaptation and habituation have been introduced successfully, providing more relevant information than sensory irritation studies in animals. Against the background of chemoperception as a dominant window of the brain on the outside world, nasal neurotoxicology is rapidly developing, focusing on olfactory and trigeminal nerve toxicity. Better insight in the processes underlying neurogenic inflammation may increase our knowledge of the causes of the various chemical sensitivity syndromes. Nasal immunotoxicology is extremely complex, which is mainly due to the pivotal role of nasal lymphoid tissue in the defense of the middle ear, eye, and oral cavity against antigenic substances, and the important function of the nasal passages in brain drainage in rats. The crucial role of tissue damage and reactive epithelial hyperproliferation in nasal carcinogenesis has become overwhelmingly clear as demonstrated by the recently developed biologically based model for predicting formaldehyde nasal cancer risk in humans. The evidence of carcinogenicity of inhaled complex mixtures in experimental animals is very limited, while there is ample evidence that occupational exposure to mixtures such as wood, leather, or textile dust or chromium- and nickel-containing materials is associated with increased risk of nasal cancer. It is remarkable that these mixtures are aerosols, suggesting that their “particulate nature” may be a major factor in their potential to induce nasal cancer. Studies in rats have been conducted with defined mixtures of nasal irritants such as aldehydes, using a model for competitive agonism to predict the outcome of such mixed exposures. When exposure levels in a mixture of nasal cytotoxicants were equal to or below the “No- Observed-Adverse-Effect-Levels” (NOAELs) of the individual chemicals, neither additivity nor potentiation was found, indicating that the NOAEL of the “most risky chemical” in the mixture would also be the NOAEL of the mixture. In vitro models are increasingly being used to study mechanisms of nasal toxicity. However, considering the complexity of the nasal cavity and the many factors that contribute to nasal toxicity, it is unlikely that in vitro experiments ever will be substitutes for in vivo inhalation studies. It is widely recognized that a strategic approach should be available for the interpretation of nasal effects in experimental animals with regard to potential human health risk. Mapping of nasal lesions combined with airflow-driven dosimetry and knowledge about local metabolism is a solid basis for extrapolation of animal data to humans. However, more research is needed to better understand factors that determine the susceptibility of human and animal tissues to nasal toxicants, in particular nasal carcinogens.

Viral particles induce Ia antigen expression on astrocytes.

Recent studies have shown that gamma-interferon (IFN-gamma) induces the expression of Ia antigen on astrocytes. This observation is of immunological significance because such activated astrocytes can act as antigen-presenting cells, as demonstrated with myelin basic protein for antigen-specific encephalitogenic T-cell lines. However, the lack of lymphatic drainage in brain and the presence of the so-called blood-brain barrier restricting traffic of cells and macromolecules suggests that IFN-gamma may not be readily available, at least during the initial phases of viral infections. The question therefore arises as to whether astrocytes can be induced to express Ia antigens by other signals directly related to viral infection and possibly independent of IFN-gamma. In the present report we demonstrate that a neurotropic murine hepatitis virus induces expression of Ia antigen on astrocytes in tissue culture without infection, rendering these brain cells competent to participate directly in the immune response to a viral infection.

Cerebrovascular Anatomy and Blood Flow Measurements in the Rabbit

The arterial supply and venous drainage of the rabbit's brain were characterized by intravascular injection of casting material and intra-arterial administration of markers (crystal violet or dissolved hydrogen gas). The internal carotid artery supplies the homolateral cerebral cortex and subcortical structures except for the thalamus and the posterior portion of the nucleus caudatus; it also supplies the homolateral retina and optic nerve. No noncerebral structures are supplied by this artery. The dorsal sagittal sinus drains the dorsal and lateral parts of the frontal and parietal areas of the cerebral cortex, with no detectable extracerebral contamination. Electromagnetic measurement of flow in the internal carotid artery (ICBF), volumetric or H2-clearance measurement of flow in the dorsal sagittal sinus (SSBF), and H2-clearance determination in cerebral cortex yield comparable results on the cerebrovascular response to hyper- and hypocapnia. ICBF and SSBF are reliable and valid estimates of average blood flow through the homolateral cerebral hemisphere and the cerebral cortex, respectively.