Parkinson Disease: Jennings D

Marek K, Jennings D. · Institute for Neurodegenerative Disorders, New Haven, CT, USA. · Neurology. · Pubmed #19221310 No free full text.

Abstract: Pathology and imaging studies have shown that patients with Parkinson disease (PD) have a prolonged period of uncertain duration when vulnerable neuronal populations are degenerating, but typical motor symptoms have not yet developed. This provides both an opportunity-it may be best to test new medications and, ultimately, treat PD patients during this early phase of disease--and a challenge--how to find these premotor PD subjects? Imaging biomarkers targeting the premotor period are critical to elucidate both the onset and progression of premotor PD. Widespread data have demonstrated that dopaminergic imaging can detect PD subjects at the motor symptom threshold. Novel strategies combining dopaminergic imaging with known genetic mutations for PD or early clinical signs and PD-associated symptoms, such as olfactory loss and sleep disturbances like REM behavior disorder, have begun to be used to identify individuals at risk for PD before motor symptoms become manifest. Early studies also have used imaging targeting norepinephrine, serotonin, cholinergic, or other neuronal systems to focus on early cardiac, cognitive, and behavioral symptoms. Imaging of nondopaminergic targets such as inflammation or alpha-synuclein deposition may provide further insight into the etiology of PD. Given the multiple genetic etiologies for PD already identified, the marked variability in the loss of dopaminergic markers measured by imaging at motor symptom onset, and the clear heterogeneity of clinical symptoms at PD onset, it is certain that many imaging biomarkers with a focus ranging from clinical symptoms to PD pathobiology to molecular genetic mechanisms, will be necessary to fully map PD risk.

Seibyl J, Jennings D, Tabamo R, Marek K. · Institute for Neurodegenerative Disorders, New Haven, CT 06510, USA. · Minerva Med. · Pubmed #16227950 No free full text.

Abstract: The development of imaging biomarkers which target specific sites in the brain represents a significant advance in neurodegenerative diseases and Parkinson's disease with the promise of new and improved approaches for the early and accurate diagnosis of disease as well as novel ways to monitor patients and assess treatment. The 3 major applications of imaging may play a role in Parkinson's disease include: 1) the use of neuroimaging as a biomarker of disease in order to improve the accuracy, timeliness, and reliability of diagnosis; 2) objective monitoring of the progression of disease to provide a molecular phenotype of Parkinson's disease which may illuminate some of the sources of clinical variability; 3) the evaluation of so-called ''disease-modifying'' treatments designed to retard the progression of disease by interfering with pathways thought implicated in the ongoing neuronal loss or replace dopamine-producing cells. Each of these areas has shown a numbers of critical clinical investigations which have better defined the utility of the imaging tools to these tasks. Nonetheless, current unresolved issues around the clinical role of neuroimaging in monitoring patients over time and validation of quantitative imaging measures of dopaminergic function are immediate issues for the field and the subject of current research efforts and the extension of the lessons learned in Parkinson's to other neurodegenerative diseases including Alzheimer's dementia.

Seibyl J, Jennings D, Tabamo R, Marek K. · Institute for Neurodegenerative Disorders, 60 Temple Street, New Haven, CT 06510, USA. · Q J Nucl Med Mol Imaging. · Pubmed #16010256 links to  free full text

Abstract: The increasing availability of PET imaging in nuclear medicine expands the armamentarium of clinical and research tools for improving diagnosis and treatment of neuropsychiatric disorders. Nonetheless, the role of SPECT imaging remains critical to both research and clinical practice. The development of rational strategies for guiding the selection of imaging modalities flows from primarily the nature of the clinical or research question and the availability of appropriate radiopharmaceuticals. There has been extensive SPECT and PET work in Parkinson's disease (PD) which highlights the value of both these scintigraphic modalities. Three main areas of interest in PD include imaging for improving diagnostic accuracy, for monitoring the progression of disease, and for assessing the therapeutic efficacy of drugs with neuroprotective potential. The demands of the clinical or research question posed to imaging dictates the selection of radiotracer and imaging modality. Diagnosis of PD represents the easiest challenge with many imaging biomarkers showing high sensitivity for detecting abnormal reduction of dopaminergic function based on qualitative review of images. On the other hand, using imaging to evaluate treatments which purportedly slow the rate of disease progression, indicated by the reduction in the rate of loss in a quantitative imaging signal in patients studied over time, represents the most rigorous requirement of the imaging measure. In each of these applications presynaptic markers of dopaminergic function using SPECT and PET have been extremely valuable. Review of neuroimaging studies of PD provides a useful example of optimized approaches to clinical and research studies in neuropsychiatric disorders.

Seibyl J, Jennings D, Tabamo R, Marek K. · Institute for Neurodegenerative Disorders, IND, 60 Temple St, Suite 8B, New Haven, CT 06510, USA. · J Neurol. · Pubmed #15505753 No free full text.

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Marek K, Jennings D, Seibyl J. · Institute for Neurodegenerative Disorders, New Haven, Connecticut 06510, USA. · Neurology. · Pubmed #14504379 No free full text.

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Marek K, Jennings D, Seibyl J. · Institute for Neurodegenerative Disorders, New Haven, CT 06510, USA. · Ann Neurol. · Pubmed #12666107 No free full text.

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Marek K, Jennings D, Seibyl J. · The Institute for Neurodegenerative Disorders, New Haven, CT 06510, USA. · Eur J Neurol. · Pubmed #12464117 No free full text.

Abstract: During the past decade, in vivo imaging of the nigrostriatal dopaminergic system has been developed as a research tool to monitor progressive dopaminergic neuron loss in Parkinson's disease (PD) and to assess the effect of medication on imaging outcomes. Recently two similar studies compared the effect of initial treatment with a dopamine agonist (pramipexole (CALM-PD CIT) or ropinirole (REAL-PET)) or levodopa on the progression of PD as measured by [123I]beta-CIT or [18F]Dopa imaging. These two clinical imaging studies targeting dopamine function with different imaging ligands and technology both demonstrate slowing in the rate of loss of [123I]beta-CIT or [18F]Dopa uptake in early PD patients treated with dopamine agonists compared with levodopa. The relative reduction in the per cent loss from baseline of [123I]beta-CIT uptake in the pramipexole versus the levodopa group was 47% at 22 months, 44% at 34 months and 37% at 46 months after initiating treatment. The relative reduction of 18F-dopa uptake in the ropinirole group versus the levodopa group was 35% at 24 months. These results should be very cautiously interpreted with regard to the effect of dopamine agonists or levodopa on clinical disease progression. These data highlight the need to compare imaging outcomes of dopamine neuronal loss with multiple meaningful clinical endpoints of disease progression in placebo controlled, larger and long-term studies.

Marek K, Jennings D, Seibyl J. · Department of Neurology, Institute for Neurogenerative Disorders, New Haven, Connecticut, USA. · Adv Neurol. · Pubmed #12442677 No free full text.

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Shoulson I, Penney J, McDermott M, Schwid S, Kayson E, Chase T, Fahn S, Greenamyre JT, Lang A, Siderowf A, Pearson N, Harrison M, Rost E, Colcher A, Lloyd M, Matthews M, Pahwa R, McGuire D, Lew MF, Schuman S, Marek K, Broshjeit S, Factor S, Brown D, Feigin A, Mazurkiewicz J, Ford B, Jennings D, Dilllon S, Comella C, Blasucci L, Janko K, Shulman L, Wiener W, Bateman-Rodriguez D, Carrion A, Suchowersky O, Lafontaine AL, Pantella C, Siemers E, Belden J, Davies R, Lannon M, Grimes D, Gray P, Martin W, Kennedy L, Adler C, Newman S, Hammerstad J, Stone C, Lewitt P, Bardram K, Mistura K, Miyasaki J, Johnston L, Cha JH, Tennis M, Panniset M, Hall J, Tetrud J, Friedlander J, Hauser R, Gauger L, Rodnitzky R, Deleo A, Dobson J, Seeberger L, Dingmann C, Tarsy D, Ryan P, Elmer L, Ruzicka D, Stacy M, Brewer M, Locke B, Baker D, Casaceli C, Day D, Florack M, Hodgeman K, Laroia N, Nobel R, Orme C, Rexo L, Rothenburgh K, Sulimowicz K, Watts A, Wratni E, Tariot P, Cox C, Leventhal C, Alderfer V, Craun AM, Frey J, McCree L, McDermott J, Cooper J, Holdich T, Read B, Anonymous00161. · No affiliation provided · Neurology. · Pubmed #11222787 No free full text.

Abstract: BACKGROUND: Preclinical studies suggest that glutamate antagonists help ameliorate motor fluctuations in patients with PD treated with levodopa. METHODS: In a multicenter, randomized, double-blind, placebo-controlled, parallel-group, dose-ranging study, the authors assessed the safety, tolerability, and efficacy of the glutamate receptor blocker remacemide hydrochloride in 279 patients with motor fluctuations treated with levodopa. The primary objective was to assess the short-term tolerability and safety of four dosage levels of remacemide during 7 weeks of treatment. Patients were also monitored with home diaries and the Unified PD Rating Scale (UPDRS) to collect preliminary data on treatment efficacy. RESULTS: Remacemide was well tolerated up to a dosage of 300 mg/d on a twice daily schedule and 600 mg/d on a four times daily schedule. The most common dosage-related adverse events were dizziness and nausea, as observed in previous studies of remacemide. The percent "on" time and motor UPDRS scores showed trends toward improvement in the patients treated with 150 and 300 mg/d remacemide compared with placebo-treated patients, although these improvements were not significant. CONCLUSION: Remacemide is a safe and tolerable adjunct to dopaminergic therapy for patients with PD and motor fluctuations. Although this study had limited power to detect therapeutic effects, the observed improvement is consistent with studies of non-human primates with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced parkinsonian signs and symptoms. Additional studies are warranted to confirm these results over an extended period of observation, and to explore the potential neuroprotective effects of remacemide in slowing the progression of PD.

Marek K, Jennings D, Tamagnan G, Seibyl J. · Institute for Neurodegenerative Disorders, New Haven, CT, USA. · Ann Neurol. · Pubmed #19127587 No free full text.

Abstract: Reliable and well-validated biomarkers for PD to identify individuals "at risk" before motor symptoms, accurately diagnose individuals at the threshold of clinical PD, and monitor PD progression throughout its course would dramatically accelerate research into both PD cause and therapeutics. Biomarkers offer the potential to provide a window onto disease mechanism, potentially generating therapeutic targets for disease. In particular, biomarkers enable investigation of the premotor period of PD before typical symptoms are manifest, but while degeneration has already begun. Given the multiple genetic causes for PD already identified, the marked variability in the loss of dopaminergic markers measured by imaging at motor symptom onset and the clear heterogeneity of clinical symptoms in PD onset and clinical progression, it is likely many biomarkers with a focus ranging from clinical symptoms to PD pathobiology to molecular genetic mechanisms will be necessary to fully map PD risk and progression. Biomarkers are also critical in new drug development for PD, both in early validation studies to assess drug dosing and to determine drug penetrance into the brain, and in later efficacy studies to complement PD clinical outcomes. During the past two decades, much progress has been made in identifying and assessing PD biomarkers, but as yet, no fully validated biomarker for PD is currently available. Nonetheless, there is increasing evidence that molecular genetics, focused -omic (proteomic, metabolomic, and transcriptomic) assessment of blood and cerebrospinal fluid, and advanced in vivo brain imaging will provide critical clues to assist in the diagnosis and medical management of PD patients.

Siderowf A, Jennings D, Connolly J, Doty RL, Marek K, Stern MB. · Parkinson's Disease and Movement Disorders Center, Department of Neurology, University of Pennsylvania, Philadelphia, Pennsylvania, USA. · Mov Disord. · Pubmed #17876851 No free full text.

Abstract: Our objective was to assess the association between risk factors for Parkinson's disease (PD) and abnormal olfaction in first-degree relatives of patients with PD. Factors including lower cigarette smoking and lower caffeine consumption have been associated with increased risk of PD. Idiopathic hyposmia has also been associated with an increased risk of PD. The relationship between risk factors for PD and impaired olfactory function has not been evaluated in relatives of PD patients. We conducted a mail survey of odor identification ability in 173 first-degree relatives of PD patients using the 40-item University of Pennsylvania Smell Identification Test (UPSIT). Respondents also completed a questionnaire inquiring about risk factors for PD including caffeine consumption, tobacco use, exercise, and exposures to heavy metals, well-water, and pesticides. There was a direct relationship between olfactory performance and lifetime caffeine intake. After adjustment for age, gender, and smoking status, subjects who reported drinking 2 to 3 cups of caffeinated beverages per day (2.6 points higher 95% CI: 0.5, 4.5) and 4 or more cups per day (3.7 points higher, 95% CI: 0.6, 6.7) had significantly better UPSIT scores than those who consumed less than 1 cup per day. There was no significant relationship between olfactory performance and other risk factors. In conclusion, abnormal olfaction is associated with significantly lower lifetime caffeine consumption in first-degree relatives of PD patients. Further research is warranted to determine whether a history of lower caffeine consumption confers additional risk for the development of PD in hyposmic relatives of PD patients.

Zubal IG, Early M, Yuan O, Jennings D, Marek K, Seibyl JP. · Institute for Neurodegenerative Disorders, and Molecular Neuroimaging, LLC, New Haven, Connecticut 06510, USA. · J Nucl Med. · Pubmed #17504864 links to  free full text

Abstract: Reliable quantitative dopamine transporter imaging is critical for early and accurate diagnosis of Parkinson's disease (PD). Image quantitation is made difficult by the variability introduced by manual interventions during the quantitative processing steps. A fully automated objective striatal analysis (OSA) program was applied to dopamine transporter images acquired from PD subjects with early symptoms of suspected parkinsonism and compared with manual analysis by a trained image-processing technologist. METHODS: A total of 101 (123)I-beta-CIT SPECT scans were obtained of subjects recruited to participate in the Query-PD Study. Data were reconstructed and then analyzed according to a package of scripts (OSA) that reorients the SPECT brain volume to the standard geometry of an average scan, automatically locates the striata and occipital structures, locates the caudate and putamen, and calculates the background-subtracted striatal uptake ratio (V3''). The striatal uptake ratio calculated by OSA was compared with manual analysis by a trained image-processing technologist. Several parameters were varied in the automated analysis, including the number of summed transverse slices and the size and separation of the regions of interest applied to the caudate and putamen to determine the optimum OSA analysis. The parameters giving V3'' with the closest correlation to the manual analysis were accepted as optimal. RESULTS: The optimal comparison between the V3'' obtained by the human analyst and that obtained by the automated OSA analysis yielded a correlation coefficient of 0.96. CONCLUSION: Our optimized OSA delivers V3'' evaluations that closely correlate with a similar evaluation manually applied by a highly trained image-processing technologist.

Dahodwala N, Connolly J, Farmer J, Stern MB, Jennings D, Siderowf A. · Department of Neurology, Pennsylvania Hospital, University of Pennsylvania, USA. · Parkinsonism Relat Disord. · Pubmed #17449316 No free full text.

Abstract: As predictive testing for Parkinson's disease (PD) becomes available, it will be important to understand in whom such testing will be used. To address this issue, we conducted a mail survey of 138 first-degree relatives of PD patients. In the absence of treatment, 60% reported that they would either "definitely" or "probably" be interested in predictive testing. In the setting of a clinical trial, this number increased to 71% (p=0.04) and when neuroprotective therapy is available, interest increased to 90% (p<0.001). Interest in predictive testing for PD is moderate in the absence of effective therapy, and goes up significantly when both clinical trial participation and neuroprotective therapy are offered.

Racette BA, Tabbal SD, Jennings D, Good L, Perlmutter JS, Evanoff B. · Department of Neurology, Washington University School of Medicine, 660 S. Euclid Ave., Box 8111, St. Louis, MO 63110, USA. · Neurology. · Pubmed #15668418 No free full text.

Abstract: OBJECTIVE: To estimate the prevalence of parkinsonism in welders in Alabama and to compare this prevalence with that in a general population sample. METHODS: The authors screened 1,423 welders from Alabama who were referred for medical-legal evaluation for Parkinson disease (PD). Standardized videotaped assessments using the Unified Parkinson's Disease Rating Scale motor subsection 3 (UPDRS3) were obtained. Patients provided information regarding exposure to welding fumes and job titles. Job titles were matched with Department of Labor Standard Occupational Codes (SOCs). Diagnoses were assigned based on quantitative criteria for the diagnosis of PD using two thresholds for diagnosis. With use of the number of active welders in this screening with parkinsonism as the numerator and the age-adjusted number of welders in each SOC as the denominator, the prevalence of parkinsonism in Alabama welders was estimated using conservative assumptions and compared with general population data from Copiah County, MS. RESULTS: With use of conservative and liberal case definitions of parkinsonism, the estimated prevalence of parkinsonism among active male welders age 40 to 69 statewide was 977 to 1,336 cases/100,000 population. The prevalence of parkinsonism was higher among welders vs age-standardized data for the general population (prevalence ratio = 10.19, 95% CI 4.43 to 23.43). CONCLUSION: The estimated prevalence of parkinsonism was higher within a sample of male Alabama welders vs the general population of male residents of Copiah County, MS.

Varrone A, Marek KL, Jennings D, Innis RB, Seibyl JP. · Department of Diagnostic Radiology, Yale University School of Medicine, New Haven, Connecticut, USA. · Mov Disord. · Pubmed #11748733 No free full text.

Abstract: In vivo imaging of the dopamine transporter (DAT) with single photon emission computed tomography (SPECT) is a quantitative biomarker for Parkinson's disease (PD) onset and severity. This study has examined and compared the loss of striatal DAT in PD and multiple system atrophy (MSA) using [(123)I]beta-CIT SPECT imaging. One hundred and eighty-three patients (157 PD and 26 MSA) were studied. Clinical rating scales (Hoehn and Yahr stage and Unified Parkinson's Disease Rating Scale [UPDRS] scores) demonstrated that the MSA patients were more severely impaired than the PD patients. The striatal [(123)I]beta-CIT SPECT uptake was markedly reduced in both the PD and MSA groups. In addition, MSA patients showed more symmetric DAT loss compared with the PD patients, consistent with the more symmetric clinical motor dysfunction observed in MSA. While the loss of DAT was significantly reduced in all regions in both MSA and PD, comparison of the relative loss of the DAT did not significantly improve diagnostic accuracy in distinguishing between PD and MSA.