Neurofilaments are the main cytoskeletal constituents in neuronal cells. They are belived to be important for maintaining the structural integrity and calibre of axons and dendrites thereby influencing the conduction velocity of nerve impulses.The neurofilament chains are divided into three groups according to their molecular size, neurofilament light (NF-L), neurofilament medium (NF-M) and neurofilament heavy (NF-H). The neurofilaments are obligate heteropolymers in vivo in which NF-L forms the backbone to which the heavier chains copolymerize to form the 10 nm neurofilament fibre. Different degenerative processes in the brain raise significant interest owing to the increasing mean age in the western world. Such diseases include amyotrophic lateral sclerosis, vascular dementia, frontal lobe dementia, progressive supra-nuclear paralysis, multiple system atrophy, low pressure hydrocephalus, and multiple sclerosis (MS). We have been able to generate six highly specific monoclonal antibodies for NF-L, and four independent epitopes were elucidated using Biacore and V8 protease degradation. Antibody 2:1 and 47:3 were selected components in a two-site ELISA assay for detection of NF-L in body fluids owing to their outstanding abililty to bind the antigen. The assay has a least detectable dose of 60 ng/l and a standard range of 60 to 64 000 ng/l. The assay was validated on its ability to detect changes of NF-L levels in CSF in patients with different neurological diseases. These were cerebral infarction, amyotrophic lateral sclerosis, relapsing remitting MS, extrapyramidal symptoms, and late onset Alzheimer’s disease. All the patient groups displayed significantly elevated NF-L levels as compared to the controls. We also tested the assay’s ability to monitor the amount of axonal breakdown in an animal model of MS. The NF-L levels were found to be elevated in rodents with chronic experimental autoimmune encephalomyelitis, giving a possible tool for monitoring new treatment strategies for axonal protection in MS. When studying a large population based MS material, we found axonal breakdown to be present early in the disease course and the breakdown was observed both in active relapse and clinically stable disease, indicative of ongoing neurodegeneration. NF-L levels were correlated to progression index, that is, high NF-L levels detected early in disease predict a fast progression of the disease. The amount of glial fibrillary acidic protein, a cytoskeletal protein found in astrocytes, was also quantified and was shown to be a good marker for the more progressive MS subtypes, that is, primary progressive and secondary progressive disease, indicating formation of astrocytic scars and activation of astrocytes. The test dealt with in this thesis has the potential to identify the slow chronic degenerative diseases with progressive disappearance of nerve cells and their large myelinated axons. There is a significant need clinically to be able to quantify such types of cell degeneration in relation to the progressive disappearance of nerve functions and to relate these different conditions to treatment regimens, disease progress, and prognosis.

Alzheimer¡¦s disease (AD) is a neurodegenerative disorder characterized by progressive deterioration of cognitive functions and the presence of intracellular neurofibrillary tangles (NFT) and extraneuronal senile plaques (SP). The major component of NFT is the hyperphosphorylated microtubules-associated protein tau. SP is consistent of extracellular deposition of £]-amyloid (A£]), mainly A£]1-42 peptide (A£]42). Given the need of tools for early and accurate diagnosis and prediction of disease progression and monitoring the efficacy of therapeutic agents for AD, development of cerebrospinal fluid (CSF) biomarkers have become a rapidly growing research field. In our study, patients with AD (n=28), non-AD dementia (n=16), other neurological disorder (OND, n=14) and healthy controls (HC, n=21) were included. Our results revealed that AD patients have significant higher CSF total tau (t-tau) and lower A£]42 levels than HC and OND groups. There is no significant difference of both CSF t-tau and A£]42 levels between AD and non-AD dementia groups. These results suggest that both CSF t-tau and A£]42 are good biomarkers for distinguishing AD from non-dementia control subjects but demonstrate less discriminating power in differentiating AD from non-AD dementia. Moreover, our results show only CSF t-tau level but not A£]42 has an inverse correlation with the score of short-term memory patients with AD (spearman: r = -0.444; p=0.018). These data indicate the higher CSF t-tau level is associated with much NFT pathology and more severe impairment of short-term memory in AD patients. In the study of the moleacular mechanism of tau¡¦s hyperphosphorylation by glycogen synthase kinase 3b (GSK3b), we show that the T231 is the primary phosphorylation site for GSK3b and the tau227-237 (AVVRTPPKSPS) derived from tau containing T231P232 motif is identified as the GSK3b binding site with high affinity of a Kd value 0.82 ¡Ó 0.16 mM. Our results suggest that direct binding and phosphorylation of T231P232 motif by GSK3b induces conformational change of tau and consequentially alters the inhibitory activity of its N-terminus that allows the sequential phosphorylation of C-terminus of tau by GSK3b. Furthermore, hyperphosphorylation reduces tau¡¦s ability to promote tubulin assembly and to form bundles in N18 cells. T231A mutant completely abolishes tau phosphorylation by GSK3b and retains the ability to promote tubulin polymerization and bundle formation. Taken together, these results suggest that phosphorylation of T231 by GSK3b may play an important role in tau¡¦s hyperphosphorylation and functional regulation.

Professional research project (Au.D.)--University of South Florida, 2000. / Title from PDF of title page. / Document formatted into pages; contains 22 pages. / Includes bibliographical references. / Text (Electronic thesis) in PDF format. / ABSTRACT: The purpose of this study was to investigate further the characteristics of hearing loss in ventriculoperitoneal (VP) shunted hydrocephalus. Twelve (VP) shunt treated hydrocephalus children participated in this study. The etiology of the hydrocephalus was either intraventricular hemorrhage or spina bifida. A recent neurological examination reported the shunt to be patent in each child. Audiometric examination included pure tone air conduction thresholds, tympanometry, contralateral and ipsilateral acoustic reflex thresholds and distortion product otoacoustic emissions (DPOAE&softsign;s). A unilateral, high frequency, sensorineural hearing loss was found in the ear ipsilateral to shunt placement in 10 (83%) of the 12 shunt treated hydrocephalic children. No hearing loss was observed the ear contralateral to shunt placement. Based on the pure tone findings coupled with the decrease in DPOAE amplitude in the shunt ear, the hearing loss appears to be cochlear in nature. It is hypothesized that the cochlear hydrodynamics are disrupted as the result of fluid pressure reduction within the perilymph being transmitted via a patent cochlear aqueduct as a reaction to the reduction of CSF via a patent shunt. In addition, a concomitant brainstem involvement is evidenced in the ART pattern possibly produced by the paten shunt draining CSF from the subdural space resulting in cranial base hypoplasia. / System requirements: World Wide Web browser and PDF reader. / Mode of access: World Wide Web.

Hematopoietic stem cell transplantation (HSCT) is a potentially curative treatment for multiple sclerosis (MS) with now more than 600 documented cases in the medical literature. Long-term remission can be achieved with this therapy, but when is it justified to claim that a patient is cured from MS? In attempt to answer this question, the outcome of the Swedish patients is described, mechanisms behind the therapeutic effect are discussed and new tools for demonstration of absence of disease have been developed. In Swedish patients treated with HSCT for aggressive MS, disease free survival was 68 % at five years, and no patient progressed after three years of stable disease. Presence of gadolinium enhancing lesions prior to HSCT was associated with a favorable outcome (disease free survival 79 % vs 46 %, p=0.028). There was no mortality and no patient required intensive care. The immune system of twelve of these patients was investigated further. In most respects HSCT-treated patients were similar to healthy controls, demonstrating normalization. In the presence of a potential antigen, leukocytes from HSCT-treated patients ceased producing pro-inflammatory IL-17 and increased production of the inhibitory cytokine TGF-β1 suggesting restoration of tolerance. Cytokine levels and biomarkers of tissue damage were investigated in cerebrospinal fluid from a cohort of MS patients. The levels were related to clinical and imaging findings. A cytokine signature of patients with relapsing-remitting MS could be identified, characterized by increased levels of CCL22, CXCL10, sCD40L, CXCL1 and CCL5 as well as down-regulation of CCL2. Further, we could demonstrate that active inflammation in relapsing-remitting MS is a tissue damaging process, with increased levels of myelin basic protein and neurofilament light. Importantly, relapsing-remitting MS patients in remission displayed no tissue damage. In secondary progressive MS, moderate tissue damage was present without signs of active inflammation. From a clinical vantage point, it seems that we confidently can claim cure of relapsing-remitting MS patients after five years absence of disease activity. The new tools for evaluation of disease can strengthen this assertion and may enable earlier prediction of outcome.

Idiopathic normal pressure hydrocephalus (iNPH) is a condition with dilated cerebral ventricles but intracranial pressure within normal limits. The symptoms of gait impairment, cognitive decline and urinary incontinence develop gradually. Treatment with shunt insertion results in improvement in eight out of ten patients. The cerebrospinal fluid tap test (CSF TT) and preoperative magnetic resonance imaging (MRI) are methods used to select patients who may benefit from shunt surgery, but they are performed and interpreted differently in different centers throughout the world. The aim of this thesis was to evaluate the performance of the CSF TT and the underlying mechanisms of improvement in gait function after CSF removal, and to investigate the prognostic value of preoperative MRI scans. Improvement in gait and changes in cerebral blood flow (CBF) after a CSF TT were investigated in two prospective studies that included 39 and 20 patients, respectively. Gait assessment and perfusion MRI were done before and several times during the first 24 hours after a CSF TT. Perfusion was investigated with pseudo-continuous arterial spin labeling. At the group level, gait function was significantly improved at all investigation times, but only one-third of individual CSF TT responders were improved at all investigation times. In patients with increased CBF in lateral and frontal white matter after the CSF TT, gait function improved more than it did in patients with decreased CBF in these regions. However, in the whole sample, there was no significant increase in CBF after CSF removal. Preoperative MRI scans were retrospectively evaluated in 109 patients with iNPH who had undergone shunt surgery. The callosal angle was smaller in shunt responders compared with non-responders. The following findings showed the highest association with a positive outcome after shunting: a small callosal angle, wide temporal horns, and occurrence of disproportionally enlarged subarachnoid space hydrocephalus. In conclusion, CBF in white matter close to the lateral ventricles may play a role in the reversibility of symptoms after CSF removal in patients with iNPH. The CSF TT should be reevaluated if the patient does not initially improve, and preoperative MRI investigations can add prognostic information regarding the selection of shunt candidates.

No description available.

Cerebrospinal fluid (CSF) infusion tests can be used to estimate the dynamic properties of the CSF system. Idiopathic normal pressure hydrocephalus (INPH) is a syndrome signified by a disturbance to the CSF system, where the cause is unknown and the diagnosis is difficult to determine. As an aid in identifying patients with INPH who will improve after shunt surgery, infusion tests are commonly used to determine the outflow conductance (Cout), or outflow resistance (Rout=1/Cout), of the CSF system. The tests are also used to determine shunt function in vivo. The general aim of this thesis was to develop and validate CSF infusion methods, to investigate the dynamics of the CSF system. The methods should be applicable to patients with INPH, to aid in the quest to further improve the diagnosis and management of this syndrome. An existing mathematical model describing the dynamics of the CSF system was further developed. The characteristics of the model were verified and the effect of expanding intracranial air on the intracranial pressure (ICP) was simulated. The simulations supported the recommendation to maintain sea-level pressure during air ambulance transportation of patients with suspected intracranial air. A recently developed infusion apparatus was evaluated, on an experimental model as well as on a patient material. The repetitiveness in estimating Cout was found to be good. A statistically significant difference was found between the repeated Cout estimations in the patient group, indicating that there might have been a small physiological change introduced during the infusion test. A parameter, ∆Cout, was proposed and evaluated. It proved to reflect the reliability of individual Cout investigations in a clinically useful way, as well as to provide easily interpreted information. An adaptive algorithm for assessment of Cout was developed and evaluated on a patient group. The new algorithm was shown to reduce the investigation time, from 60 minutes, by 14.3 ± 5.9 minutes (mean ± SD), p<0.01, without reducing the reliability of the estimated Cout below clinically relevant levels. The relationship between ICP and CSF outflow was studied in a group of patients investigated for INPH. It was found that in the range of moderate increase from baseline pressure, the assumption of a pressure independent Rout was confirmed (p=0.5). However, at larger pressure increments, the relationship had a non-linear tendency (p<0.05). This indicates that the traditional view of a pressure independent Rout might have to be questioned in the region where ICP exceeds baseline pressure too much. Infusion tests can be performed in different ways, where three main categories may be distinguished. The bolus infusion method was compared to the constant pressure and constant flow infusion methods, on an experimental model as well as on a patient material. When physiological pressure fluctuations were added to the model, significant differences were found in the determination of Cout in the range of clinical importance, i.e. low Cout (p<0.05). The finding was supported by the patient investigations, the difference was however not significant. With the application of the new methods developed in this thesis, and the increased knowledge concerning relationships between CSF dynamic parameters, the CSF infusion test was further improved with the ability to increase measurement reliability in a reduced time. This constitutes a good basis to perform a large multi-centre study with the main goal to determine the predictive value of the parameter Cout.

Following a head concussion the intracranial pressure increases due to the impact, which cannot be adequately relieved because of the stiffness of the skull. Popular strategies aimed at decompressing the head consist in the administration of osmotic agents and skull removal. The mechanical properties of bone can be affected by the administration of different solutions. If the malleability of skull is influenced by the osmotic agents that are administered to the patient then the pressure and volume in the intracranial cavity can also be modified following the treatment. In this thesis research, we hypothesize that administered osmotic agents can influence the mechanical properties of the skull, which can also impact the volume the cavity can hold and subsequently the pressure in the head. This premise was tested by modifying existing mathematical models compiled through two general MATLAB codes that allow the computation of a non-symbolic differential-algebraic initial value problem. Three main features were changed in comparison to current models: the skull's influence on the pressure and volume modulation was tested (inputs were obtained from skull tested under different solutions); pulsatile flow was accounted for on the creation and movement of cerebrospinal fluid; and the input on the mechanical behavior of the cranial vessels was accounted for through previously published continuum-mechanics vessel-behavior models. To complete the model, materials and mechanical properties were obtained through laboratory experiments as well as data collection from existing literature. From our bone test we were able to conclude that there are different factors that affect the mechanical properties of bone in various degrees. There is a mild statistical correlation (p-value 0.05) between the mechanical properties of bone obtained from different regions of the skull samples (2-14mm) and the DPBS and hDPBS solutions. Additionally there is a strong statistical difference (p-value 0.05) between the mechanical properties obtained from cross head speed (0.02, 0.002, and 0.004 (mm/s)) and solution variation (DI, DPBS and hDPBS). Finally, we were able to see that there seems to be a correlation between the mechanical properties of bone, the solution treatments and hypertension; although more test need to be developed to affirm this premise since our results are preliminary.

Bibliography: leaves 249-283. / xi, 283 leaves : ill. (chiefly col.) ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / This thesis examines the hypothesis that cerebrospinal fluid (CSF) is driven from the subarachnoid space into perivascular spaces and the central canal by arterial pulsations and that this is the driving force for the development of non-communicating syringomyelia. Horseradish peroxidase (HRP) is used as a CSF tracer in rats and sheep. A technique for studying the three-dimensional morphology of the human central canal is also developed. / Thesis (Ph.D.)--University of Adelaide, Dept. of Surgery, 1997?

Diss. (sammanfattning) Uppsala : Sveriges lantbruksuniv. / Härtill 4 uppsatser.