Biomedical subjects
Publications and source records attributed to Andrew Lees.
We describe a patient with juvenile levodopa-responsive Parkinsonism who reported a dramatic response to cigarette smoking with transient but marked improvement of motor symptoms associated with oculogyric crises and psychotic behavior. His beta-CIT single-photon emission computed tomography scan showed a complete absence of presynaptic dopaminergic nerve terminals.
This article presents the revision process, major innovations, and clinimetric testing program for the Movement Disorder Society (MDS)-sponsored revision of the Unified Parkinson's Disease Rating Scale (UPDRS), known as the MDS-UPDRS. The UPDRS is the most widely used scale for the clinical study of Parkinson's disease (PD). The MDS previously organized a critique of the UPDRS, which cited many strengths, but recommended revision of the scale to accommodate new advances and to resolve problematic areas. An MDS-UPDRS committee prepared the revision using the recommendations of the published critique of the scale. Subcommittees developed new material that was reviewed by the entire committee. A 1-day face-to-face committee meeting was organized to resolve areas of debate and to arrive at a working draft ready for clinimetric testing. The MDS-UPDRS retains the UPDRS structure of four parts with a total summed score, but the parts have been modified to provide a section that integrates nonmotor elements of PD: I, Nonmotor Experiences of Daily Living; II, Motor Experiences of Daily Living; III, Motor Examination; and IV, Motor Complications. All items have five response options with uniform anchors of 0 = normal, 1 = slight, 2 = mild, 3 = moderate, and 4 = severe. Several questions in Part I and all of Part II are written as a patient/caregiver questionnaire, so that the total rater time should remain approximately 30 minutes. Detailed instructions for testing and data acquisition accompany the MDS-UPDRS in order to increase uniform usage. Multiple language editions are planned. A three-part clinimetric program will provide testing of reliability, validity, and responsiveness to interventions. Although the MDS-UPDRS will not be published until it has successfully passed clinimetric testing, explanation of the process, key changes, and clinimetric programs allow clinicians and researchers to understand and participate in the revision process.
Previously we have shown that the H1c haplotype on the background of the H1 clade of haplotypes at the MAPT locus is associated with increased risk for progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and Alzheimer's disease (AD). Here we replicated the association with AD in an additional autopsy confirmed series. We show that this haplotype increases both the expression of total MAPT transcript as well as specifically increasing the proportion of 4 microtubule binding repeat containing transcripts. We discuss these findings both in terms of the problems facing the dissection of the etiologies of complex traits and the pathogenesis of the tauopathies.
Mutations in the LRRK2 gene, coding for dardarin, cause dominantly inherited Parkinson's disease (PD). Dardarin is a large protein, and mutations are found throughout the gene including the kinase domain. However, it is not clear if kinase activity is important for the damaging effects of pathogenic mutations. In this study, we noted two cellular phenotypes associated with mutant dardarin. First, pathogenic mutations increase the tendency of dardarin to form inclusion bodies. Secondly, neurons and neuronal cell lines undergo cell death after expression of mutant protein. Manipulating activity by replacing the kinase domain with a 'kinase-dead' version blocks inclusion body formation and strongly delays cell death. This predicts that kinase inhibitors will be useful therapeutic agents in patients with LRRK2 mutations and, perhaps, in sporadic PD. We also show that dardarin protein is expressed within human midbrain neurons and that C-terminal epitopes are also found in some Lewy bodies.
The pathological distinctions between the various clinical and pathological manifestations of frontotemporal lobar degeneration (FTLD) remain unclear. Using monoclonal antibodies specific for 3- and 4-repeat isoforms of the microtubule associated protein, tau (3R- and 4R-tau), we have performed an immunohistochemical study of the tau pathology present in 14 cases of sporadic forms of FTLD, 12 cases with Pick bodies and two cases without and in 27 cases of familial FTLD associated with 12 different mutations in the tau gene (MAPT), five cases with Pick bodies and 22 cases without. In all 12 cases of sporadic FTLD where Pick bodies were present, these contained only 3R-tau isoforms. Clinically, ten of these cases had frontotemporal dementia and two had progressive apraxia. Only 3R-tau isoforms were present in Pick bodies in those patients with familial FTLD associated with L266V, Q336R, E342V, K369I or G389R MAPT mutations. Patients with familial FTLD associated with exon 10 N279K, N296H or +16 splice site mutations showed tau pathology characterised by neuronal neurofibrillary tangles (NFT) and glial cell tangles that contained only 4R-tau isoforms, as did the NFT in P301L MAPT mutation. With the R406W mutation, NFT contained both 3R- and 4R-tau isoforms. We also observed two patients with sporadic FTLD, but without Pick bodies, in whom the tau pathology comprised only of 4R-tau isoforms. We have therefore shown by immunohistochemistry that different specific tau isoform compositions underlie the various kinds of tau pathology present in sporadic and familial FTLD. The use of such tau isoform specific antibodies may refine pathological criteria underpinning FTLD.
Myelin proteolipid protein (PLP), the major protein of mammalian CNS myelin, is a member of the proteolipid gene family (pgf). It is an evolutionarily conserved polytopic integral membrane protein and a potential autoantigen in multiple sclerosis (MS). To analyze antibody recognition of PLP epitopes in situ, monoclonal antibodies (mAbs) specific for different regions of human PLP (50-69, 100-123, 139-151, 178-191, 200-219, 264-276) were generated and used to immunostain CNS tissues of representative vertebrates. mAbs to each region recognized whole human PLP on Western blots; the anti-100-123 mAb did not recognize DM-20, the PLP isoform that lacks residues 116-150. All of the mAbs stained fixed, permeabilized oligodendrocytes and mammalian and avian CNS tissue myelin. Most of the mAbs also stained amphibian, teleost, and elasmobranch CNS myelin despite greater diversity of their pgf myelin protein sequences. Myelin staining was observed when there was at least 40% identity of the mAb epitope and known pgf myelin proteins of the same or related species. The pgf myelin proteins of teleosts and elasmobranchs lack 116-150; the anti-100-123 mAb did not stain their myelin. In addition to myelin, the anti-178-191 mAb stained many neurons in all species; other mAbs stained distinct neuron subpopulations in different species. Neuronal staining was observed when there was at least approximately 30% identity of the PLP mAb epitope and known pgf neuronal proteins of the same or related species. Thus, anti-human PLP epitope mAbs simultaneously recognize CNS myelin and neurons even without extensive sequence identity. Widespread anti-PLP mAb recognition of neurons suggests a novel potential pathophysiologic mechanism in MS patients, i.e., that anti-PLP antibodies associated with demyelination might simultaneously recognize pgf epitopes in neurons, thereby affecting their functions.
OBJECTIVE: To investigate the significance of PINK1 mutations in sporadic Parkinson's disease (PD). METHODS: We determined the frequency of PINK1 mutations by direct sequencing in a large series of PD patients with apparently sporadic disease (n = 768). RESULTS: Twelve heterozygous mutations were identified, nine in PD patients and three in control subjects. INTERPRETATION: Given the difficulty in interpreting the pathogenic significance of the heterozygous mutations that have already been reported in parkin and DJ-1, we first determined the frequency of heterozygous PINK1 mutations in the general population by sequencing a large number of control subjects (n = 768), then subsequently assessed their functional significance by examining their effects on stress-induced alterations to the mitochondrial membrane potential (DeltaPsim). We demonstrate an enrichment of heterozygous mutations in sporadic PD patients compared with matched control subjects (1.2% in PD vs 0.4% in control subjects). Furthermore, we show that they adversely affect DeltaPsim in a similar way to the familial G309D mutation. Although it remains difficult to conclusively demonstrate the pathogenicity of heterozygous mutations, the results of this study and the previously reported subclinical nigrostriatal dysfunction in carriers of heterozygous PINK1 mutations suggest the possibility that these heterozygous mutations are a significant risk factor in the development of later onset PD.
Piribedil is a D2 dopamine agonist, which has been shown to improve symptoms of Parkinson's disease (PD) when combined with L-dopa. The objective of this study was to compare the efficacy of piribedil monotherapy to placebo in patients with early PD over a 7-month period. Four hundred and five early PD patients were randomized (double-blind) to piribedil (150-300 mg/day) or placebo. L-dopa open-label supplementation was permitted. Unified Parkinson Disease Rating Scale part III (UPDRS III) score as the last observation on monotherapy over 7 months was the primary outcome measure. Secondary outcomes were proportion of responders (UPDRS III improvement > 30%), patients remaining on monotherapy after 7 months, UPDRS III subscores, and UPDRS II. UPDRS III improved on piribedil (-4.9 points) versus a worsening on placebo (2.6 points; estimated effect = 7.26 points; 95% CI = 5.38-9.14; P < 0.0001). The proportion of responders was significantly higher for piribedil (42%) than for placebo (14%) (OR = 4.69; 95% CI = 2.82-7.80; P < 0.001). Piribedil significantly improved several UPDRS III subscores. UPDRS II improved on piribedil by -1.2 points, while it deteriorated by 1.5 points on placebo (estimated effect = 2.71; 95% CI = 1.8-3.62; P < 0.0001). The proportion of patients remaining on monotherapy after 7 months was greater in the piribedil group (OR = 3.72; 95% CI = 2.26-6.11; P < 0.001). Safety was consistent with that reported for other dopamine agonists, gastrointestinal side effects being the most common (22% of patients in piribedil group vs. 14% on placebo). Piribedil is effective and safe as early PD therapy.
In Alzheimer's disease (AD) the accumulation of pathological forms of the beta-amyloid (Abeta) peptide are believed to be causal factors in the neurodegeneration that results in the loss of cognitive function in patients. Anti-Abeta antibodies have been shown to reduce Abeta levels in transgenic mouse models of AD and in AN-1792 clinical trial on AD patients; however, the clinical trial was halted when some patients developed meningoencephalitis. Theories on the cause of the adverse events include proinflammatory "primed patients," a Th1-inducing adjuvant, and Abeta autoreactive T cells. New immunotherapy approaches are being developed to eliminate these putative risk factors. Mannan, which is recognized by pattern recognition receptors of the innate immune system, can be utilized as a molecular adjuvant to promote a Th2-mediated immune response to conjugated B cell epitopes. The N-terminus of Abeta was conjugated to mannan, and used to immunize mice with low concentrations of immunoconjugate, without a conventional adjuvant. Mannan induced a significant and highly polarized toward Th2 phenotype anti-Abeta antibody response not only in BALB/c, but also in B6SJL F1 mice. New preclinical trials in AD mouse models may help to develop novel immunogen-adjuvant configurations with the potential to avoid the adverse immune response that occurred in the first clinical trial.
We report a sporadic tauopathy of 6-year duration in a 76-year-old woman. Her initial symptoms were asymmetrical parkinsonism and muscle weakness, with apraxia appearing 2 years later. The brain showed frontal and temporal cerebral atrophy; severe neuronal loss and gliosis were observed in the precentral cortex (loss of Betz cells was also evident) and premotor area, and in the medial temporal lobe, including the temporal tip, amygdala, and hippocampal CA1-subiculum border zone. The substantia nigra showed moderate neuronal loss and gliosis. In the spinal cord, loss of the anterior horn cells and degeneration of the corticospinal tracts were a characteristic feature. In addition, in the affected regions, the remaining neurons were often found to contain intracytoplasmic inclusions resembling neurofibrillary tangles. Tau immunostaining revealed widespread glial-predominant lesions in the cerebral gray and white matter. In contrast, predominance of neuronal lesions (pretangles/tangles) was a feature in the subcortical gray matter, including the spinal cord. The remaining upper and lower motor neurons were also affected by tau pathology. Accumulated tau in these glial cells and neurons was clearly recognized by a specific antibody against four-repeat (4R) tau. The ultrastructural presence of tau-positive tubular structures was confirmed in the glial cells and neurons (tangles). Immunoblotting of a frozen frontal lobe sample revealed accumulation of 4R-predominant tau isoforms. No mutations were found in the tau gene. These findings indicate that a sporadic 4R tauopathy can cause frontotemporal degeneration, parkinsonism, and motor neuron disease. The present case could represent a new clinicopathological phenotype of non-familial tauopathy.
Applications of oxime chemistry are described for the efficient bioconjugation of proteins and polysaccharides for the preparation of conjugate vaccines. A number of approaches are described in this manuscript to functionalize proteins and polysaccharides with aminooxy (AO) groups and aldehydes which could then be covalently linked to each other via oxime formation, without the need for reduction. By using limiting numbers of active groups on each component, the extent of inter- and intramolecular crosslinking could be controlled. The approaches described are compatible and complementary to a number of chemistries currently used in conjugate vaccine synthesis. Oxime chemistry can be used to both simplify the synthesis of and increase yields of conjugate vaccines. Mice immunized with pneumococcal type 14 conjugates that were made using oxime chemistry mounted significant anti-polysaccharide immune responses. The primary immune response could be boosted, indicating that the polysaccharide conjugate had characteristics of a T cell dependent antigen.
The reason for the high frequency of depression and anxiety in Parkinson's disease is poorly understood. Degeneration of neurotransmitter systems other than dopamine might play a specific role in the occurrence of these affective disorders. We used [11C]RTI-32 PET, an in vivo marker of both dopamine and noradrenaline transporter binding, to localize differences between depressed and non-depressed patients. We studied eight and 12 Parkinson's disease patients with and without a history of depression matched for age, disease duration and doses of antiparkinsonian medication. The depressed Parkinson's disease cohort had lower [11C]RTI-32 binding than non-depressed Parkinson's disease cases in the locus coeruleus and in several regions of the limbic system including the anterior cingulate cortex, the thalamus, the amygdala and the ventral striatum. Exploratory analyses revealed that the severity of anxiety in the Parkinson's disease patients was inversely correlated with the [11C]RTI-32 binding in most of these regions and apathy was inversely correlated with [11C]RTI-32 binding in the ventral striatum. These results suggest that depression and anxiety in Parkinson's disease might be associated with a specific loss of dopamine and noradrenaline innervation in the limbic system.
The effect of pergolide 25 mug twice daily on levodopa initiation was assessed in a randomized, placebo-controlled, parallel group, double-blind multicenter trial in 106 untreated early Parkinson's disease patients. The primary endpoint of mean time until levodopa was 520 days (95% confidence interval [CI], 422-618 days) for pergolide versus 434 days (95% CI, 358-609 days) for placebo. However, this increase of 86 days for pergolide was not statistically significant. The wash-in effect of pergolide was significant at 6 weeks (change in mean Unified Parkinson's Disease Rating Scale [UPDRS] 2 and 3 was -0.1 [95% CI, -1.4 to 1.3] for pergolide vs. 2.2 [95% CI, 1.1-3.3] for placebo). At termination, the change from baseline in mean UPDRS 2 and 3 score was 11.4 (95% CI, 8.8-14) for pergolide and 14.6 (95% CI, 12-17.2) for placebo (P=0.08). There was no significant change in UPDRS 2 and 3 for the 83 patients achieving the planned 4-week washout at termination (pergolide 1.2 [95% CI, -0.8 to 3.2] vs. placebo 0.0 [95% CI, -1.6 to 1.6]. Adverse events were infrequent and occurred equally for pergolide and placebo. The study shows no evidence of a neuroprotective effect but indicates a mild symptomatic benefit from pergolide at a dose normally considered subtherapeutic.
Increasing antibiotic resistance and a rising patient population at risk for infection due to impaired immunity underscore the importance of vaccination against pneumococci. However, available capsular polysaccharide vaccines are often poorly immunogenic in patients at risk for pneumococcal disease. The goal of this study was to explore the potential of peptide mimotopes to function as alternative vaccine antigens to elicit a type-specific antibody response to pneumococci. We used a human monoclonal immunoglobulin A (IgA) antibody (NAD) to type 8 Streptococcus pneumoniae capsular polysaccharide (type 8 PS) to screen a phage display library, and the phage PUB1 displaying the peptide FHLPYNHNWFAL was selected after three rounds of biopanning. Inhibition studies with phage-displayed peptide or the peptide PUB1 and type 8 PS showed that PUB1 is a mimetic of type 8 PS. PUB1 conjugated to tetanus toxoid (PUB1-TT) induced a type 8 PS-specific antibody response in BALB/c mice, further defining it as a mimotope of type 8 PS. The administration of immune sera obtained from PUB1-TT-immunized mice earlier (days 14 and 21) and later (days 87 and 100) after primary and reimmunization resulted in a highly significant prolongation of the survival of naive mice after pneumococcal challenge compared to controls. The survival of PUB1-TT-immunized mice was also prolonged after pneumococcal challenge nearly 4 months after primary immunization. The efficacy of PUB1-TT-induced immune sera provides proof of principle that a mimotope-induced antibody response can protect against pneumococci and suggests that peptide mimotopes selected by type-specific human antibodies could hold promise as immunogens for pneumococci.
BACKGROUND AND METHODS: A Markov model was developed to evaluate the cost-effectiveness of levodopa/carbidopa/entacapone (LCE;Stalevo), in the treatment of patients with Parkinson's disease (PD) and end-of-dose motor fluctuations (wearing-off). LCE, with or without other antiparkinsonian medications, was compared to UK standard care, comprising traditional levodopa/ dopa-decarboxylase inhibitor (DDCI) with other antiparkinsonian medications (e.g. selegiline or dopamine agonists) added as needed. The costs and outcomes of both treatments were projected over a period of 10 years from the perspective (a) of society as a whole and (b) of the UK National Health Service (NHS). Sensitivity analyses, including second-order Monte Carlo simulations, were performed to assess the confidence level of the primary results. RESULTS: Treatment with LCE produced an average gain of +1.04 quality-adjusted life-years (QALYs) per patient (2.57 vs. 1.53) in the base-case analysis (discount rate 3.5%). This gain was accompanied by a reduction in the total 10-year direct cost of care to society of 10198 pounds per patient ( approximately E14800). From the societal perspective, therefore, LCE was dominant, producing better clinical outcomes with lower costs. This dominance was reiterated in all sensitivity analyses of society-focused analysis, including a shortening of the time-frame to 5 years. Although treatment with LCE resulted in an increase in direct costs per patient of 3239 pounds (25756 pounds versus 22517 pounds) to the NHS over the 10-year period analysed, the incremental cost-effectiveness ratio (ICER) of LCE was only 3105 pounds per QALY gained (approximately E4500). All ICERs to the NHS remained below 3800 pounds per QALY gained in univariate sensitivity analyses applying different discount rates. When a shorter, 5-year, time-horizon was analysed, the NHS-related ICER for LCE was 6526 pounds per QALY gained. All these ICERs are within the range usually considered to indicate acceptable or highly acceptable cost effectiveness (defined as < 30000 pounds per QALY gained). The results of the Monte Carlo simulations indicated that the likelihood of LCE being either 'dominant' or more effective at an 'acceptable cost' from either the societal or the NHS perspective was high, exceeding 96% in the base-case sensitivity analysis, and was 93% even when all the uncertainties associated with the model were taken into consideration simultaneously. In particular, compared to standard care, the probability that LCE would provide better outcomes at a lower cost to society as a whole was 77% in the base-case sensitivity analysis and 72% in the scenario involving the highest degree of uncertainty. CONCLUSIONS: In the UK the use of LCE to treat PD patients with wearing-off is beneficial to individual patients and likely to offer money savings to society as a whole, compared with UK standard therapy. The added cost of the medication itself is exceeded by the savings made in other direct costs of PD, mainly those relating to social care or PD-related private expenditures.
Parkinson's disease (PD) is primarily a disease of elderly patients. This article reviews current knowledge and recent developments relating to drugs that can be used as alternatives to levodopa as initial treatment of PD. Synthetic orally acting dopamine agonists have found increasing favour as an option for early PD in relatively young patients. This strategy is based on evidence that this approach may delay the onset of motor fluctuations, at least during the first 5 years of treatment. Subcutaneous apomorphine infusions may attenuate motor fluctuations in late-stage disease, and transdermal rotigotine, a dopamine agonist in development, has also been shown to be efficacious. The greater proclivity for dopamine agonists to cause psychotoxicity has, however, limited their routine use in the elderly. Selective monoamine oxidase type B (MAO-B) inhibitors, used as monotherapy, delay the need for the introduction of levodopa by about 9 months. These agents appear to be less efficacious than dopamine agonists but are better tolerated. Concern has been expressed about the potential of the MAO-B inhibitor selegiline (deprenyl) to induce cardiovascular adverse effects (orthostatic hypotension), either directly or through its amphetamine catabolites. Rasagiline is a new MAO-B inhibitor that is not broken down to amphetamine derivatives and is indicated as both monotherapy in early PD and as adjunctive therapy in PD patients with motor fluctuations. Two older classes of agents have undergone a resurgence of interest in recent years. Amantadine, which enhances dopaminergic transmission and has antiglutamate activity, is occasionally used as monotherapy but has recently been widely used as an antidyskinetic agent in late-stage PD. Anticholinergic drugs, such as benztropine (benzatropine) and orphenadrine also provide control of symptoms when used as monotherapy, but their psychotoxic, cognitive and autonomic adverse events make them inappropriate for the treatment of the elderly. Effective therapy in PD should prevent disease progression and abolish motor and cognitive handicap. Currently, none of the existing drugs meets all these needs.
BACKGROUND: Cholinergic deficits are prominent in patients who have dementia associated with Parkinson's disease. We investigated the effects of the dual cholinesterase inhibitor rivastigmine in such patients. METHODS: Patients in whom mild-to-moderate dementia developed at least 2 years after they received a clinical diagnosis of Parkinson's disease were randomly assigned to receive placebo or 3 to 12 mg of rivastigmine per day for 24 weeks. Primary efficacy variables were the scores for the cognitive subscale of the Alzheimer's Disease Assessment Scale (ADAS-cog) and Alzheimer's Disease Cooperative Study-Clinician's Global Impression of Change (ADCS-CGIC). Secondary clinical outcomes were the scores for the Alzheimer's Disease Cooperative Study-Activities of Daily Living, the 10-item Neuropsychiatric Inventory, the Mini-Mental State Examination, Cognitive Drug Research power of attention tests, the Verbal Fluency test, and the Ten Point Clock-Drawing test. RESULTS: A total of 541 patients were enrolled, and 410 completed the study. The outcomes were better among patients treated with rivastigmine than among those who received placebo; however, the differences between these two groups were moderate and similar to those reported in trials of rivastigmine for Alzheimer's disease. Rivastigmine-treated patients had a mean improvement of 2.1 points in the score for the 70-point ADAS-cog, from a baseline score of 23.8, as compared with a 0.7-point worsening in the placebo group, from a baseline score of 24.3 (P<0.001). Clinically meaningful improvements in the scores for the ADCS-CGIC were observed in 19.8 percent of patients in the rivastigmine group and 14.5 percent of those in the placebo group, and clinically meaningful worsening was observed in 13.0 percent and 23.1 percent, respectively (mean score at 24 weeks, 3.8 and 4.3, respectively; P=0.007). Significantly better outcomes were seen with rivastigmine with respect to all secondary efficacy variables. The most frequent adverse events were nausea (affecting 29.0 percent of patients in the rivastigmine group and 11.2 percent of those in the placebo group, P<0.001), vomiting (16.6 and 1.7 percent, P<0.001), and tremor (10.2 and 3.9 percent, P=0.01). CONCLUSIONS: In this placebo-controlled study, rivastigmine was associated with moderate improvements in dementia associated with Parkinson's disease but also with higher rates of nausea, vomiting, and tremor.
Patients with Parkinson's disease may use Dopamine Replacement Therapy (DRT) in excess of therapeutic need. We investigate whether a group of 10 patients with Parkinson's disease, provisionally diagnosed with "Hedonistic Homeostatic Dysregulation" because of their excessive use of DRT, met established operational psychiatric criteria for substance dependence, compared with 10 patients with Parkinson's disease compliant with prescribed DRT. Using a semi-structured questionnaire designed to distinguish between adaptive therapeutic dependence on DRT and a maladaptive pathological pattern of DRT use, in conjunction with the SCID-1, we found that seven of the patients deemed by their treating physicians to be misusing DRT fulfilled operational criteria for maladaptive dependence in contrast to none of the compliant group. The majority experienced dysphoric "withdrawal" symptoms in the "off" state and increased their dose of DRT in an effort to control their mood. They also continued to use high doses of DRT despite disabling dyskinesias and social difficulties. This study provides preliminary evidence that some patients with Parkinson's disease may become maladaptively dependent on DRT. This finding has both clinical relevance for the treatment of PD and further implicates dopaminergic pathways in the genesis of substance dependence.