Δ9-tetrahydrocannabinol (Δ9-THC) exerts a direct neuroprotective effect in a human cell culture model of Parkinson's disease.

AIMS: Δ9-tetrahydrocannabinol (Δ9-THC) is neuroprotective in models of Parkinson's disease (PD). Although CB1 receptors are increased within the basal ganglia of PD patients and animal models, current evidence suggests a role for CB1 receptor-independent mechanisms. Here, we utilized a human neuronal cell culture PD model to further investigate the protective properties of Δ9-THC. METHODS: Differentiated SH-SY5Y neuroblastoma cells were exposed to PD-relevant toxins: 1-methyl-4-phenylpyridinium (MPP+), lactacystin and paraquat. Changes in CB1 receptor level were determined by quantitative polymerase chain reaction and Western blotting. Cannabinoids and modulatory compounds were co-administered with toxins for 48 h and the effects on cell death, viability, apoptosis and oxidative stress assessed. RESULTS: We found CB1 receptor up-regulation in response to MPP+, lactacystin and paraquat and a protective effect of Δ9-THC against all three toxins. This neuroprotective effect was not reproduced by the CB1 receptor agonist WIN55,212-2 or blocked by the CB1 antagonist AM251. Furthermore, the antioxidants α-tocopherol and butylhydroxytoluene as well as the antioxidant cannabinoids, nabilone and cannabidiol were unable to elicit the same neuroprotection as Δ9-THC. However, the peroxisome proliferator-activated receptor-gamma (PPARγ) antagonist T0070907 dose-dependently blocked the neuroprotective, antioxidant and anti-apoptotic effects of Δ9-THC, while the PPARγ agonist pioglitazone resulted in protection from MPP+-induced neurotoxicity. Furthermore, Δ9-THC increased PPARγ expression in MPP+-treated SH-SY5Y cells, another indicator of PPARγ activation. CONCLUSIONS: We have demonstrated up-regulation of the CB1 receptor in direct response to neuronal injury in a human PD cell culture model, and a direct neuronal protective effect of Δ9-THC that may be mediated through PPARγ activation.

The feminisation of British neurology: implications for workforce planning.

As in other hospital specialties, an increasing proportion of neurology trainees are female. To predict the workforce implications it is necessary to determine what life choices future neurologists will make. A questionnaire survey of life choices was administered to neurology consultants and trainees, general medical senior house officers, and medical students. Of the 344 respondents, 3% of specialist registrars (SpRs) and 4.6% of consultants work part time. Eighty-seven per cent of female and 22% of male junior doctors plan to work part time for, on average, 7.5 and 1.5 years respectively. Thirty percent of consultants also plan to work part time. A number of SpRs (14.3%) and consultants (6%) have taken a career break while 37.5% of SpRs and 18.2% of consultants are planning a career break. The changing demands of both sexes will have a greater impact on the neurology workforce than the increasing proportion of women alone. Increased part-time working will require additional trainees to ensure service requirements are met.

Rare variants analysis of cutaneous malignant melanoma genes in Parkinson's disease.

A shared genetic susceptibility between cutaneous malignant melanoma (CMM) and Parkinson's disease (PD) has been suggested. We investigated this by assessing the contribution of rare variants in genes involved in CMM to PD risk. We studied rare variation across 29 CMM risk genes using high-quality genotype data in 6875 PD cases and 6065 controls and sought to replicate findings using whole-exome sequencing data from a second independent cohort totaling 1255 PD cases and 473 controls. No statistically significant enrichment of rare variants across all genes, per gene, or for any individual variant was detected in either cohort. There were nonsignificant trends toward different carrier frequencies between PD cases and controls, under different inheritance models, in the following CMM risk genes: BAP1, DCC, ERBB4, KIT, MAPK2, MITF, PTEN, and TP53. The very rare TYR p.V275F variant, which is a pathogenic allele for recessive albinism, was more common in PD cases than controls in 3 independent cohorts. Tyrosinase, encoded by TYR, is the rate-limiting enzyme for the production of neuromelanin, and has a role in the production of dopamine. These results suggest a possible role for another gene in the dopamine-biosynthetic pathway in susceptibility to neurodegenerative Parkinsonism, but further studies in larger PD cohorts are needed to accurately determine the role of these genes/variants in disease pathogenesis.

Reversal of parkinsonian symptoms in primates by antagonism of excitatory amino acid transmission: potential mechanisms of action.

Parkinsonism is characterised by overactive glutamatergic transmission in the cortico-striatal and subthalamo-medial pallidal pathways. Local blockade of glutamatergic transmission in these pathways can alleviate parkinsonian symptoms. The effectiveness of the treatment, however, is often limited by the simultaneous appearance of unwanted side-effects. These side-effects, including ataxia and dissociative anaesthesia, are particularly problematic when N-methyl-D-aspartate (NMDA) antagonists are used. In an attempt to overcome these problems we have attempted to manipulate excitatory amino acid (EAA)-mediated neurotransmission indirectly by targeting the NMDA receptor associated modulatory sites. We review evidence which demonstrates that antagonists for both the NMDA associated glycine and polyamine sites can reverse parkinsonian symptoms when injected intra-cerebrally in both MPTP-treated and bilateral 6-OHDA lesioned marmosets without eliciting unwanted side-effects. We further review preliminary data which suggest that ifenprodil, a polyamine site antagonist, has striking anti-parkinsonian actions in the marmoset. Potential mechanisms of action underlying these effects are discussed in terms of NMDA receptor subtypes and the neuroanatomical locus of action. The anti-parkinsonian efficacy of intra-striatally administered EAA antagonists leads us to question the view of dopamine acting in the striatum as a simple neuromodulator.

Neurochemical and behavioural investigations of the NMDA receptor-associated glycine site in the rat striatum: functional implications for treatment of parkinsonian symptoms.

The glutamatergic cortico-striatal and subthalamo-entopeduncular pathways are both overactive in parkinsonism. Previous behavioural investigations have shown that intra-entopeduncular injection of either NMDA-site or glycine-site antagonists results in alleviation of parkinsonian symptoms, although injection of the former is associated with the appearance of anaesthetic-like side effects. These behavioural differences may be mediated by action on different NMDA receptor subtypes. Recent neurochemical and molecular pharmacological studies have indicated the existence of NMDA receptor subtypes which display differential modulation by glycine. In the present study, three potential modes of NMDA antagonism were differentiated in vitro by effects on [3H]-glycine binding to striatal sections. Specific [3H]-glycine binding was totally displaced by the glycine partial agonist (R)-HA-966; the NMDA-site antagonist D-CPP had no effect; and the NMDA-site antagonist D-AP5 displaced [3H]-glycine binding in a subpopulation of glycine sites. The anti-parkinsonian effects of (R)-HA-966, D-CPP and D-AP5 were assessed by intra-striatal injection in reserpine-treated rats and 6-OHDA-lesioned rats. Injection of (R)-HA-966 and D-CPP resulted in alleviation of parkinsonian akinesia, although the latter elicited anaesthetic-like side effects; D-AP5 was ineffective as an anti-parkinsonian agent. (R)-HA-966 was also effective as an anti-parkinsonian agent when administered systemically in the reserpine-treated rat. These data suggest that different classes of NMDA antagonist mediate different behavioural responses within the parkinsonian striatum. The behavioural response produced may depend on the exact nature of the conformational change induced by the antagonist and the location of the subtype most sensitive to that class of compound. Selection of a specific mode of NMDA receptor antagonism or targeting of striatal NMDA receptor subtypes may form the basis of a novel therapeutic approach to Parkinson's disease.

Designing clinical trials in older people.

Adequate medical care of the increasingly ageing population requires robust clinical trial data both to inform treatment decisions, and to understand the natural history of diseases which primarily affect the elderly. However, this information is widely lacking, which is likely to have significant clinical consequences. Under-representation of older people in clinical trials is well documented, the reasons including physicians' perception, protocol eligibility criteria, and functional status requirements. Many clinical trial designs remain conservative and there is no established standardised methodology for recruiting more elderly patients with co-morbidities and disability into clinical trials. Designing clinical trials in older people poses a unique set of challenges, particularly regarding recruitment, retention and data analysis. In this review we outline the difficulties encountered in conducting clinical trials in older patients and describe some of the initiatives that can be put in place to counteract them. It is only by addressing these challenges with careful and adequately resourced protocol design that clinical trials may successfully address the therapeutic questions raised by our ageing population.

Changes in iron-regulatory gene expression occur in human cell culture models of Parkinson's disease.

BACKGROUND: Neuronal iron accumulation is thought to be relevant to the pathogenesis of Parkinson's disease (PD), although the mechanism remains elusive. We hypothesized that neuronal iron uptake may be stimulated by functional mitochondrial iron deficiency. OBJECTIVE: To determine firstly whether the mitochondrial toxin, 1-methyl-4-phenylpyridinium iodide (MPP(+)), results in upregulation of iron-import proteins and transporters of iron into the mitochondria, and secondly whether similar changes in expression are induced by toxins with different mechanisms of action. METHODS: We used quantitative PCR and Western blotting to investigate expression of the iron importers, divalent metal transporter, transferrin receptor 1 and 2 (TfR1 and TfR2) and mitoferrin-2 and the iron exporter ferroportin in differentiated SH-SY5Y cells exposed to three different toxins relevant to PD, MPP(+), paraquat (a free radical generator) and lactacystin (an inhibitor of the ubiquitin-proteasome system (UPS)). RESULTS: MPP(+) resulted in increased mRNA and protein levels of genes involved in cellular iron import and transport into the mitochondria. Similar changes occurred following exposure to paraquat, another inducer of oxidative stress. Lactacystin also resulted in increased TfR1 mRNA levels, although the other changes were not found. CONCLUSION: Our results support the hypothesis of a functional mitochondrial iron deficit driving neuronal iron uptake but also suggest that differences exist in neuronal iron handling induced by different toxins.

Quantifying the impact of dyskinesias in PD: the PDYS-26: a patient-based outcome measure.

BACKGROUND: Drug-induced dyskinesias are a common and disabling clinical problem in the long-term management of Parkinson disease (PD). Their management and the development of new treatments rely on rigorous and meaningful dyskinesia measurement. Although clinician-based approaches exist, patient-based measures are limited. METHOD: Potential rating scale items concerning daily activities affected by dyskinesias were generated from patients, literature review, and expert opinion. The resulting 42-item questionnaire was administered to 98 patients known to have problematic dyskinesias; 72 patients were invited to complete it twice for test-retest reliability (trt). Rasch analysis guided scale development. Results were cross-validated using traditional psychometric methods by examining scaling assumptions (item means and variances, item-total correlations), reliability (Cronbach alpha, trt), and validity (factor analysis). External validation was performed against standard dyskinesia measures: blinded video rating using modified Goetz and Abnormal Involuntary Movements Scales (AIMS), and Unified PD Rating Scale (UPDRS) questions 32-34. RESULTS: Response rates were high. Fourteen items were removed because of high missing data. The remaining items were Rasch analyzed. Two items were removed because of misfit. The resulting 26 items formed a clinically and statistically conformable set. Traditional psychometric criteria were satisfied and external validation showed good correlation with the UPDRS items and moderate to good correlation with objective dyskinesia measures. CONCLUSION: The 26-item Parkinson Disease Dyskinesia Scale (PDYS-26) satisfied multiple criteria for reliable and valid measurement. Correlations with objective measures suggest that it captures related but not identical constructs. As a patient-derived scale that generates linear measurements, it could complement existing clinician-based dyskinesia measures.

Association of the H63D polymorphism in the hemochromatosis gene with sporadic ALS.

Iron misregulation promotes oxidative stress and abnormally high iron levels have been found in the spinal cords of patients with ALS. The authors investigated whether HFE gene polymorphisms, linked to hemochromatosis, are associated with ALS using two independent populations of patients with sporadic ALS and controls (totaling 379 patients and 400 controls). They found that the H63D polymorphism is overrepresented in individuals with sporadic ALS (odds ratio 1.85, CI: 1.35 to 2.54).

Reversal of parkinsonian symptoms by intrastriatal and systemic manipulations of excitatory amino acid and dopamine transmission in the bilateral 6-OHDA lesioned marmoset.

We have investigated the potential of alleviating parkinsonian symptoms by manipulating excitatory amino acid (EAA) transmission, by several different pharmacological means, in a novel primate model of parkinsonism. The model is based on a two-stage bilateral 6-hydroxydopamine lesion procedure in marmosets, which produces a stable but marked parkinsonian condition. Parkinsonian symptoms were reversed in a dose-dependent manner by systemic administration of levodopa and intrastriatal injections of apomorphine administered into either the caudate nucleus or the putamen. (R)-HA-966, a partial agonist for the NMDA receptor associated glycine site, also alleviated parkinsonian symptoms when injected intrastriatally but not when injected systemically. Systemic injection of enadoline, a kappa opiate which blocks release of EAAs, reduced parkinsonian symptoms when injected systemically, though it did not restore completely normal motor behaviour. In contrast, ifenprodil, an antagonist for the NMDA receptor-associated polyamine modulatory site, when injected systemically at an optimal dose, resulted in apparently normal motor behaviour. These data suggest that attenuation of EAA transmission could be used to treat parkinsonism.

The pallidotomy debate.

It has been suggested that image-guidance and macro-stimulation alone are not sufficiently accurate to result in safe and effective lesion localization in pallidotomy for Parkinson's disease when compared with micro-electrode recording. This review analyses the data in the series published to date, and compares the safety and efficacy of the two techniques, finding no evidence to support this claim. In addition, evidence regarding the necessary accuracy of lesion placement is reviewed.

Morphea limited to the superficial reticular dermis: an underrecognized histologic phenomenon.

Morphea (localized scleroderma) is a disease of unknown etiology, presenting as circumscribed areas of indurated skin. Histologically, most cases of morphea feature thickened collagen bundles in the deep reticular dermis, sometimes also extending into the superficial dermis or into the subcutis. We present six cases of morphea in which typical histologic features were restricted to the superficial dermis and contrast these with 27 additional biopsies of conventional morphea seen during the same time period. Sections were stained for elastic fibers, and dermal dendritic cells were labeled with antibodies to CD34 and Factor XIIIa. All six cases showed thickened collagen bundles restricted to the superficial dermis, sparing the deep dermis and without associated evidence of lichen sclerosus et atrophicus (LSA). Dermal elastic fibers were not appreciably decreased in number. There was loss of CD34-positive dermal spindle cells in each of our six superficial examples of morphea, which was restricted to the area of altered collagen in four of the six cases. This report highlights the distinctly uncommon phenomenon of morphea presenting solely as alteration of the superficial reticular dermis, without features of LSA. The selective loss of CD34-labeled spindle cells may provide information regarding the role of these putative immune accessory cells in morphea. Recognition of this manifestation of morphea may be helpful diagnostically.

Severely atypical medium-sized congenital nevus with widespread satellitosis and placental deposits in a neonate: the problem of congenital melanoma and its simulants.

We describe a neonate with a highly atypical melanocytic proliferation that arose in a medium-sized congenital nevus, in association with multiple cutaneous satellite lesions and placental deposits. The patient's pathologic findings and benign clinical course to date raise the problem of diagnosis of congenital melanoma and the importance of clinical follow-up to determine the biologic behavior of severely atypical, histologically malignant proliferations in congenital melanocytic nevi.

Numerous eruptive lesions of panniculitis associated with group A streptococcus bacteremia in an immunocompetent child.

A previously healthy 13-month-old boy developed group A beta-hemolytic streptococcus bacteremia coinciding with numerous eruptive subcutaneous lesions primarily on his extremities. Skin biopsy revealed infectious panniculitis; gram-positive cocci were present within both fat lobules and septa. Molecular genetic analysis of an isolate from the patient's blood revealed an emm type 4 organism displaying the emm chromosomal pattern E that is characteristic of opacity factor-producing strains; the organism also harbored the gene encoding for streptococcal pyrogenic exotoxin C (speC). To our knowledge, this clinical presentation has not yet been described in the spectrum of infections directly caused by group A beta-hemolytic streptococci.

Cannabis for dyskinesia in Parkinson disease: a randomized double-blind crossover study.

BACKGROUND: The long-term treatment of Parkinson disease (PD) may be complicated by the development of levodopa-induced dyskinesia. Clinical and animal model data support the view that modulation of cannabinoid function may exert an antidyskinetic effect. The authors conducted a randomized, double-blind, placebo-controlled crossover trial to examine the hypothesis that cannabis may have a beneficial effect on dyskinesia in PD. METHODS: A 4-week dose escalation study was performed to assess the safety and tolerability of cannabis in six PD patients with levodopa-induced dyskinesia. Then a randomized placebo-controlled crossover study (RCT) was performed, in which 19 PD patients were randomized to receive oral cannabis extract followed by placebo or vice versa. Each treatment phase lasted for 4 weeks with an intervening 2-week washout phase. The primary outcome measure was a change in Unified Parkinson's Disease Rating Scale (UPDRS) (items 32 to 34) dyskinesia score. Secondary outcome measures included the Rush scale, Bain scale, tablet arm drawing task, and total UPDRS score following a levodopa challenge, as well as patient-completed measures of a dyskinesia activities of daily living (ADL) scale, the PDQ-39, on-off diaries, and a range of category rating scales. RESULTS: Seventeen patients completed the RCT. Cannabis was well tolerated, and had no pro- or antiparkinsonian action. There was no evidence for a treatment effect on levodopa-induced dyskinesia as assessed by the UPDRS, or any of the secondary outcome measures. CONCLUSIONS: Orally administered cannabis extract resulted in no objective or subjective improvement in dyskinesias or parkinsonism.