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Norman Relkin

Publications and source records attributed to Norman Relkin.

17 recordsLinked to original sources
PubMed2007

Cerebrospinal fluid proteomic biomarkers for Alzheimer's disease.

OBJECTIVE: To find a panel of proteins in antemortem cerebrospinal fluid (CSF) that could be used to differentiate between samples from Alzheimer's disease (AD) patients and samples from healthy and neurological control subjects. METHODS: For a test cohort, antemortem CSF proteins from 34 AD and 34 non-AD patients were separated using two-dimensional gel electrophoresis. The resulting protein patterns were analyzed using the random forest multivariate statistical method. Protein spots of interest were identified using tandem time-of-flight mass spectrometry. A validation cohort consisting of CSF from 18 AD patients and 10 non-AD subjects was analyzed in a similar way. RESULTS: Using the test cohort, a panel of 23 spots was identified that could be used to differentiate AD and non-AD gels with a sensitivity of 94%, a specificity of 94%, and a predicted classification error rate of only 5.9%. These proteins are related to the transport of beta-amyloid, the inflammatory response, proteolytic inhibition, and neuronal membrane proteins. The 23 spots separately classified the validation cohort with 90% sensitivity (probable AD subjects), 83% specificity, and a predicted classification error rate of 14% in a blinded analysis. The total observed sensitivity is 93%, the total observed specificity is 90%, and the predicted classification error rate is 8.3%. INTERPRETATION: A panel of possible CSF biomarkers for AD has been identified using proteomic methods.

Alzheimer Disease↗
PubMed2007

Normal pressure hydrocephalus.

Idiopathic normal pressure hydrocephalus (INPH) is a treatable neurological disorder in older adults involving disturbances of gait/balance, control of micturition, and/or cognition in combination with enlargement of the cerebral ventricles. Diagnosis can be challenging due to its varied presentation and overlap with other disorders common in the elderly. Evidence-based consensus guidelines for diagnosis and treatment of INPH have been created that can assist in clinical management. Diagnosis requires clinical documentation of one or more of the characteristic symptoms of INPH in combination with a brain imaging study demonstrating nonobstructive ventricular enlargement disproportionate to cerebral atrophy. Gait and balance disturbances are the most common presenting findings in INPH and may occur alone or together with cognitive and urinary symptoms. Adjunct tests, particularly those involving transient removal of cerebrospinal fluid via lumbar puncture or lumbar drain, can serve the dual purpose of adding to diagnostic certainty and assisting in prognostication about response to treatment. Prognostication is important because neurosurgical treatment by placement of a ventricular shunt, while effective, carries the risk of potentially significant morbidity. Outcome of shunting in INPH is most often successful when patients are accurately diagnosed, suitably evaluated for surgical candidacy, and managed carefully throughout the preoperative, surgical, and postoperative periods.

Brain↗
PubMed2006

Proteomic analysis of cerebrospinal fluid changes related to postmortem interval.

BACKGROUND: The study of proteins with altered production in postmortem cerebrospinal fluid (CSF) compared with antemortem CSF may improve the understanding of biochemical changes that occur immediately after death. METHODS: Two CSF samples (1 antemortem and 1 postmortem) were collected from 7 patients and analyzed by 2-dimensional gel electrophoresis. An analysis was also performed to identify proteins that showed a correlation between concentration change and postmortem interval. Tandem mass spectrometry was used to identify the proteins. RESULTS: Fifty-four protein spots were identified that showed a consistent and significant change in concentration in the postmortem CSF of all 7 patients (>3.5-fold, P <0.01). The proteins in these spots derive from a variety of functional groups, including cytoskeletal proteins, enzymes involved in glycolysis, and proteins that prevent oxidative stress. Fourteen protein spots were found to have an increase in production that correlated with postmortem interval. CONCLUSIONS: Changes in protein production of postmortem vs antemortem CSF were studied. The proteins observed to change production in the postmortem CSF include several proteins previously observed as potential stroke biomarkers.

Aged↗
PubMed2005

The value of supplemental prognostic tests for the preoperative assessment of idiopathic normal-pressure hydrocephalus.

OBJECTIVE: The diagnosis and management of idiopathic normal-pressure hydrocephalus (INPH) remains unclear. Moreover, the value of supplementary tests to predict which patients would benefit from placement of a shunt has not been established. This report develops evidence-based guidelines for the use of supplementary tests as an aid in prognosis. METHODS: MEDLINE searches from 1966 to the present were undertaken by use of the query NPH, normal-pressure hydrocephalus, lumbar drain, CSF [cerebrospinal fluid] tap test, and external CSF drainage in humans. This resulted in 242 articles. To provide a scientific, evidence-based review, we have chosen to restrict our analysis to clinically relevant studies usually consisting of large numbers of shunted NPH patients. Studies that did not specify INPH or secondary NPH were considered in a separate evidentiary table. RESULTS: Evidence-based guidelines for use in supplementary tests have been developed. A positive response to a 40- to 50-ml tap test has a higher degree of certainty for a favorable response to shunt placement than can be obtained by clinical examination. However, the tap test cannot be used as an exclusionary test because of its low sensitivity (26-61%). Determination of the CSF outflow resistance via an infusion test carries a higher sensitivity (57-100%) compared with the tap test and a similar positive predictive value of 75 to 92%. Prolonged external lumbar drainage in excess of 300 ml is associated with high sensitivity (50-100%) and high positive predictive value (80-100%). CONCLUSION: To date, a single standard for the prognostic evaluation of INPH patients is lacking. However, supplemental tests can increase predictive accuracy for prognosis to greater than 90%. Additional multicenter prospective randomized clinical trials are needed.

Cerebrospinal Fluid Shunts↗
PubMed2005

Diagnosing idiopathic normal-pressure hydrocephalus.

OBJECTIVE: The precise incidence and prevalence of idiopathic normal-pressure hydrocephalus (INPH) is not known, and evidence-based clinical diagnostic criteria have not been developed previously. This report contains evidence-based guidelines for clinical diagnosis of INPH that are intended to facilitate future epidemiological studies of INPH, promote earlier and more accurate diagnosis, and ultimately improve treatment outcome. METHODS: The criteria for the diagnosis of INPH are based on evidence from the medical literature, supplemented as necessary by expert opinion. From 1966 to 2003, 653 publications on "normal-pressure hydrocephalus" were cited in MEDLINE, including 29 articles that met the more stringent criteria of including "idiopathic normal-pressure hydrocephalus" in their title. Additional studies were considered that explicitly identified INPH cases and/or specified the criteria for a diagnosis of INPH. Studies were graded according to the class of evidence and results summarized in evidentiary tables. For issues of clinical relevance that lacked substantive evidence from the medical literature, the opinions of consulting experts were considered and contributed to "Options." RESULTS: Evidence-based guidelines for the clinical diagnosis of INPH have been developed. A detailed understanding of the range of clinical manifestations of this disorder and adherence to practice guidelines should improve the timely and accurate recognition of this disorder. CONCLUSION: It is recommended that INPH be classified into probable, possible, and unlikely categories. We hope that these criteria will be widely applied in clinical practice and will promote greater consistency in patient selection in future clinical investigations involving INPH.

Behavioral Symptoms↗
PubMed2005

Surgical management of idiopathic normal-pressure hydrocephalus.

OBJECTIVE: To develop evidence-based guidelines for surgical management of idiopathic normal-pressure hydrocephalus (INPH). Compared with the diagnostic phase, the surgical management of INPH has received less scientific attention. The quality of much of the literature concerning the surgical management has been limited by many factors. These include retrospective analysis, small patient numbers, analysis of a mixed NPH population, and sometimes a lack of detail as to what type of shunt system was used. Many earlier studies predated our current understanding of the hydrodynamics of cerebrospinal fluid shunts, and therefore, the conclusions drawn may no longer be valid. METHODS: A MEDLINE and PubMed search from 1966 to the present was conducted using the following key terms: normal-pressure hydrocephalus and idiopathic adult-onset hydrocephalus. Only English-language literature in peer-reviewed journals was reviewed. The search was further limited to articles that described the method of treatment and outcome selectively for INPH patients. Finally, only studies that included 20 or more INPH patients were considered with respect to formulating the recommendations in these Guidelines (27 articles). RESULTS: For practical reasons, it is important to identify probable shunt responders diagnosed with INPH. If the patient is an acceptable candidate for anesthesia, then an INPH-specific risk-benefit analysis should be determined. In general, patients exhibiting negligible symptoms may not be suitable candidates for surgical management, given the known risks and complications associated with shunting INPH. The choice of valve type and setting should be based on empirical reasoning and a basic understanding of shunt hydrodynamics. The most conservative choice is a valve incorporating an antisiphon device, with the understanding that underdrainage (despite a low opening pressure) may occur in a small percentage of patients because of the antisiphon device. On the basis of retrospective studies, the use of an adjustable valve seems to be beneficial in the management of INPH. CONCLUSION: The treatment of INPH should not be considered lightly, given the seriousness of the potential complications. Within these limitations and the available evidence, guidelines for surgical management were developed.

Cerebrospinal Fluid Shunts↗
PubMed2005

Outcome of shunting in idiopathic normal-pressure hydrocephalus and the value of outcome assessment in shunted patients.

OBJECTIVE: To develop guidelines for assessing shunt outcome in patients with idiopathic normal-pressure hydrocephalus (INPH). To date, the literature available on this topic has been marked by disparate definitions of clinical improvement, varying postoperative follow-up protocols and periods, and substantial differences in the postoperative management. Because specific criteria for defining clinical improvement are seldom reported, conclusions drawn about shunt outcome may be subjective. METHODS: A MEDLINE search back to 1966 was undertaken using the query NPH, normal-pressure hydrocephalus, shunting, shunt treatment, shunt response, outcome, and clinical outcome. The criteria for selection were studies that included INPH from 1966 to the present in which the outcome of INPH was reported in patient groups of 20 or more. RESULTS: To date, there is no standard for outcome assessment of shunt treatment in INPH. The variable improvement rates reported are not only because of different criteria for selection of patients but also because of different postoperative assessment procedures and follow-up intervals. CONCLUSION: Studies that have established fixed protocols for follow-up have shown that short- and long-term periods after shunting are determined by many factors. Whereas short-term results were more likely to be influenced by shunt-associated risks, long-term results were independent of factors inherent to the shunt procedure and shunt complications, i.e., death and morbidity related to concomitant cerebrovascular and vascular diseases. Studies have shown that beyond 1 year after surgery, these factors definitely influence the clinical effect of shunting, making the 1-year postshunt period a potential determinant of the shunt outcome. Guidelines for outcome assessment were developed on the basis of the available evidence and consensus of expert opinion.

Cerebrospinal Fluid Shunts↗
PubMed2005

Development of guidelines for idiopathic normal-pressure hydrocephalus: introduction.

OBJECTIVE: There are no currently accepted evidence-based guidelines for the diagnosis and management of the normal-pressure hydrocephalus (NPH) patient. As a result, an independent study group was assembled to address this issue and determine the feasibility of developing standardized guidelines, which would be acceptable in the United States and abroad and would be based on the available scientific evidence. The guidelines were to encompass value of clinical presentation, value of supplementary diagnostic tests, surgical management, and outcome assessment. METHODS: Initially, a series of 10 questions were formulated in the areas of pathophysiology, diagnosis, and treatment to obtain a consensus by panels of experts (see Acknowledgments) assembled in San Antonio, TX, in September 2000. This workshop provided significant insight into the difficulties in developing NPH guidelines, and a consensus was reached as to those questions involving expert opinion. Subsequently, evidentiary tables were developed on the basis of the available evidence. Only those studies with 20 or more idiopathic NPH (INPH) patients were included. RESULTS: Sensitivity, specificity, and positive and negative predictive values for INPH diagnostic criteria were assessed, and guidelines were developed on the basis of the available evidence. Recommendations for classification of INPH and additional studies were documented. CONCLUSION: The development of the guidelines was made difficult because systematic studies of INPH and patient numbers were few. It was decided to maintain the classification of NPH into two major categories, INPH and those of known cause (secondary NPH). Many studies "mixed" these classifications, and as a result, they could not be used in the evidentiary tables. Despite these problems, evidence-based guidelines were developed, and it is hoped that they will be useful in guiding clinical management of the INPH patient.

Evidence-Based Medicine↗
PubMed2003

Increased plasma levels of matrix metalloproteinase-9 in patients with Alzheimer's disease.

Matrix metalloproteinases (MMPs) may play a role in the pathophysiology of Alzheimer's disease (AD). MMP-9 and tissue inhibitors of metalloproteinases (TIMPs) are elevated in postmortem brain tissue of AD patients. MMPs and TIMPs are found in neurons, microglia, vascular endothelial cells and leukocytes. The aim of this study was to determine whether circulating levels of MMP-2, MMP-9, TIMP-1 and TIMP-2 are elevated in the plasma of AD patients. We compared AD patients to age- and gender-matched controls as well as to Parkinson's disease (PD) and amyotrophic lateral sclerosis (ALS) patients. There was constitutive expression of gelatinase A (MMP-2), and gelatinase B (MMP-9), in all the samples as shown by zymographic analysis. Levels of MMP-9 were significantly (P=0.003) elevated in the plasma of AD patients as compared to controls. Plasma levels of MMP-2, TIMP-1 and TIMP-2 were unchanged. There were no significant changes of MMP-2, MMP-9, TIMP-1 and TIMP-2 levels in PD and ALS samples. TIMP-1 and TIMP-2 were significantly correlated with MMP-9 in the AD patients. ApoE genotyping of plasma samples showed that levels of MMP-2, TIMP-1 and TIMP-2 and MMP-9 were not significantly different between the ApoE subgroups. These findings indicate that circulating levels of MMP-9 are increased in AD and may contribute to disease pathology.

Aged↗
PubMed2003

Increased diffusion in the brain of professional boxers: a preclinical sign of traumatic brain injury?

BACKGROUND AND PURPOSE: Professional boxing is associated with chronic, repetitive head blows that may cause brain injuries. Diffusion-weighted imaging is sensitive to microscopic changes and may be a useful tool to quantify the microstructural integrity of the brain. In this study, we sought to quantify microscopic alterations associated with chronic traumatic brain injury in professional boxers. METHODS: MR and diffusion-weighted imaging were performed in 24 boxers and in 14 age- and sex-matched control subjects with no history of head trauma. Using distribution analysis, the average diffusion constant of the entire brain (BD(av)) and diffusion distribution width (sigma) were calculated for each subject; findings in professional boxers were compared with those of control subjects. In the boxer group, correlations between diffusion changes and boxing history and diffusion changes and MR imaging findings were assessed. RESULTS: The measured diffusion values in the boxer group were significantly higher than those measured in the control group (BD(av), P <.0001; sigma, P <.01). In the boxer group, a robust correlation was found between increased BD(av) and frequency of hospitalization for boxing injuries (r = 0.654, P <.05). The most common MR finding in the boxer group was volume loss inappropriate to age followed by cavum septum pellucidum, subcortical white matter disease, and periventricular white matter disease. CONCLUSION: Boxers had higher diffusion constants than those in control subjects. Our data suggest that microstructural damage of the brain associated with chronic traumatic brain injury may elevate whole-brain diffusion. This global elevation can exist even when routine MR findings are normal.

Adult↗
PubMed2002

Studies of potential cerebrospinal fluid molecular markers for Alzheimer's disease.

There is a need for a reliable, molecular-based ante mortem diagnostic test for Alzheimer's disease (AD). In this study, we examined the use of two-dimensional protein electrophoresis for generating molecular barcodes which may be useful for the clinical differentiation of AD patients from normals. We compared cerebrospinal fluid samples taken from AD patients with confirmed post mortem pathology to comparable specimens from normal volunteers. Using canonical correlation analysis, a panel of nine molecular markers were identified which segregated diseased cases from normal controls. Using the scaled volume image analysis variable, a principal factor analysis was also used to distinguish normal from AD spinal fluid, based on molecular markers identified using a heuristic clustering algorithm. The use of panels of molecular markers derived from proteomic analysis may offer the best prospect for developing molecular diagnostic tests for complex neurodegenerative disorders such as AD.

Adult↗
PubMed2002

Patients with Alzheimer disease have lower levels of serum anti-amyloid peptide antibodies than healthy elderly individuals.

Active immunization with the human amyloid peptide (Abeta42) or passive immunization with anti-Abeta42 antibodies protects mice that express a mutant human amyloid precursor protein (APP) transgene from cerebral amyloid deposits. If anti-Abeta42 antibodies protect APP-transgenic mice, a model of Alzheimer's disease (AD), a high titer of anti-Abeta42 antibodies may protect humans from AD. The titer of anti-Abeta42 antibodies in serum from individuals with and without late onset AD was measured using an ELISA. The titer of Ig (IgM, IgG and IgA) and IgG anti-Abeta42 peptide antibodies was significantly higher in serum from elderly controls than AD patients. Furthermore, IgG but not Ig anti-Abeta42 antibodies distinguished sera from AD patients and elderly controls that did not have the apolipoprotein E4 allele. The low titer of anti-Abeta42 antibodies in AD patients does not reflect the well-established, age-associated defect in the antibody response to most protein antigens, as there was no positive correlation between the serum titer of anti-Abeta42 antibodies and anti-influenza hemagglutinin antibodies induced by influenza vaccine in elderly humans. The lower titer of serum anti-Abeta42 peptide antibodies in AD patients may reflect the reported specific impairment of helper T cell activity for B cells that produce anti-amyloid-beta42 peptide antibodies in APP-transgenic mice.

Aged↗
PubMed2002

Human cerebrospinal fluid apolipoprotein E isoforms are apparently inefficient at complexing with synthetic Alzheimer's amyloid-[beta] peptide (A[beta] 1-40 ) in vitro.

BACKGROUND: Variation at the apolipoprotein E locus on chromosome 19 plays a role in more cases of Alzheimer's disease than does any other identified genetic determinant. We have previously reported the isoform-specific interaction of native human apolipoprotein E (APOE, gene; apoE, protein) epsilon 3 with the amyloid-ss peptide, Ass(1-40), the major component of the cerebral amyloid deposits that appear to cause Alzheimer's disease. MATERIALS AND METHODS: In order to investigate the apoE: A beta interaction further, a modified assay was developed based on co-immunoprecipitation of the complex using an anti-apoE antibody (anti-apoE IP assay). RESULTS: Application of this assay demonstrated that the interaction of Ass(1-40) and apoE can be distinguished into two types: sodium dodecyl sulfate (SDS) -resistant and SDS-releasable. The SDS-resistant interaction between epsilon;3 and Ass(1-40) is apparently maximal at an Ass(1-40) concentration of approximately 75 micro M, and an Ass(1-40) /epsilon 3 molar ratio of about 250:1. The major apoE-isoform-specific difference in interaction with Ass(1-40) is the ability of Ass(1-40) to form SDS- resistant complexes with epsilon 3 but not with epsilon 4. Using the anti-apoE co-IP assay, we found that human cerebrospinal fluid (CSF) epsilon 3 can also form an SDS-resistant complex with Ass(1-40) but human CSF epsilon;4 cannot. However, when compared with apoE epsilon;3 collected from the conditioned medium of APOE epsilon 3-transfected cells, the competence of equal concentrations of CSF apoE epsilon 3 to form SDS-resistant complexes with Ass(1-40) is apparently diminished. A 1:1 mixture of CSF plus apoE epsilon 3-containing conditioned medium is associated with diminished Ass(1-40) /epsilon;3 complex formation to a greater extent than that observed when an identical volume of phosphate-buffered saline is added to apoE epsilon;3 medium. CONCLUSIONS: These results suggest the presence in CSF of factors that interfere with the formation of complexes between synthetic Ass(1-40) and apoE epsilon 3.

Alzheimer Disease↗
PubMedDate not supplied

Reasons for seeking genetic susceptibility testing among first-degree relatives of people with Alzheimer disease.

Advances in genetic research have provided a basis for susceptibility testing for Alzheimer disease (AD). Prior surveys have examined attitudes toward genetic testing for AD in hypothetical scenarios, but it is unclear what reasons would motivate people to seek testing in real-life situations. This study presents data from the first randomized trial to evaluate genetic susceptibility testing for asymptomatic adult children of people with AD. We examined (1) reasons endorsed as motivations for seeking testing, (2) demographic characteristics associated with these reasons, and (3) how these reasons related to the eventual decision to pursue testing. Eligible participants were 206 adult children of people with AD (mean age 53 years; 72% female; 93% white), 77.7% of whom (n = 160) went on to seek testing. Participants endorsed numerous reasons for seeking susceptibility testing (mean 7.2), encompassing a range of motivations. The most commonly endorsed reasons were as follows: (1) to contribute to research (93.9%), (2) to arrange personal affairs (87.4%), and (3) the hope that effective treatment will be developed (86.8%). Women strongly endorsed more reasons for seeking testing than men (p < 0.05). The best predictor of actual pursuit of testing was strong endorsement of the need to prepare family members for AD (odds ratio = 3.3, p < 0.01). Findings suggest that genetic susceptibility testing is of interest to individuals at risk for AD for a variety of reasons, even in the relative absence of available treatments.

Alzheimer Disease↗
PubMedDate not supplied

Estimating risk curves for first-degree relatives of patients with Alzheimer's disease: the REVEAL study.

PURPOSE: The REVEAL study is a randomized, controlled study of the psychological and behavioral impact of APOE disclosure in a risk assessment protocol provided to first degree relatives of patients with Alzheimer's disease. The protocol presents risk information as cumulative incidence curves. This article describes how these curves were estimated. METHODS: Curves were calculated using Bayes' rule to compute the posterior survival curves incorporating APOE information. RESULTS: A combination of survival data from the MIRAGE study and gender- and age-specific APOE odds ratios were used to create risk curves for males and females within each of the 6 APOE genotypes. CONCLUSION: Utilizing comparative genotype relative risk information and survival data from family studies, estimates of gender-, age-, and genotype-specific risk can be generated for use in a risk assessment research study that features genotype disclosure.

Adult↗