Neural transplantation in Huntington disease: long-term grafts in two patients.

OBJECTIVE: Clinical trials of fetal neural tissue transplantation for Huntington disease (HD) have been conducted with variable clinical results. However, no long-term analysis of graft survival and integration has been published. Here, we report the pathologic findings in two patients with HD who died 74 and 79 months after transplantation. METHODS: Methods used were pathologic examination, histochemistry, and immunohistochemistry. RESULTS: Neostriatum from both patients showed typical neuropathologic changes of advanced HD. Surviving grafts were identified in both patients (6/6 sites and 7/8 sites, respectively) as well-demarcated nests within host neostriatum with associated needle tracts. Grafted neurons adopted either dominant calbindin/parvalbumin or calretinin immunoreactivity (IR). Few neurofilament, MAP-2, DARPP-32, tyrosine hydroxylase, or calbindin IR processes traversed the host parenchyma-graft interface despite minimal junctional gliosis. Immunohistochemistry for CD68 showed microgliosis that was more pronounced in host striatum than graft. Scattered CD45 and CD3 IR cells were present within grafts and host parenchyma. No ubiquitin IR neuronal intranuclear inclusions were identified in graft neurons, although these were prevalent in host cells. CONCLUSIONS: These two autopsies confirm previous findings of neuronal differentiation and survival of transplanted fetal tissue from the ganglionic eminence and also demonstrate viability of neurons from fetal transplants in human neostriatum for more than 6 years. Despite prolonged survival, these grafts had poor integration with host striatum that is likely responsible for lack of clear clinical improvement in these patients.

Parkinson's disease risks associated with dietary iron, manganese, and other nutrient intakes.

BACKGROUND: Dietary influences on oxidative stress have been thought to play important role in the etiology of PD. OBJECTIVE: To examine associations of PD with dietary nutrients, including minerals, vitamins, and fats. METHODS: A population-based case-control study was conducted among newly diagnosed case (n = 250) and control subjects (n = 388) identified between 1992 and 2002 from enrollees of the Group Health Cooperative health maintenance organization in western Washington state. Controls were frequency matched to cases on sex and age. In-person interviews elicited data on food frequency habits during most of adult life. Nutrient intakes were calculated and analyzed by adjusting each person's nutrient intake by their total energy intake (the nutrient density technique). RESULTS: Subjects with an iron intake in the highest quartile compared with those in the lowest quartile had an increased risk of PD (odds ratio = 1.7, 95% CI: 1.0, 2.7, trend p = 0.016). There was an apparent joint effect of iron and manganese; dietary intake above median levels of both together conferred a nearly doubled risk compared with lower intakes of each nutrient (odds ratio = 1.9, 95% CI: 1.2, 2.9). No strong associations were found for either antioxidants or fats. CONCLUSION: A high intake of iron, especially in combination with high manganese intake, may be related to risk for PD.

Genetic polymorphisms of microsomal and soluble epoxide hydrolase and the risk of Parkinson's disease.

Oxidative stress is hypothesized to play a major role in the destruction of dopaminergic neurons, which is associated with Parkinson's disease. Epoxides are potentially reactive intermediates formed through the oxidative metabolism of both exogenous and endogenous substances that contribute to cytotoxic damage mediated by oxidative stress. The microsomal (EPHX1) and soluble (EPHX2) epoxide hydrolases function to regulate the oxidation status of a wide range of xenobiotic- and lipid-derived substrates; therefore, interindividual variation in these pathways may mitigate epoxide-related cellular injury. In this investigation, we examined the potential association between the risk of Parkinson's disease and genetic variation within the EPHX1 and EPHX2 genes. Fluorescent 5' nuclease-based assays were developed to identify the allelic status of individuals with respect to specific single nucleotide polymorphisms in exons 3 and 4 of the EPHX1 gene and exons 8 and 13 of the EPHX2 gene. EPHX1 and EPHX2 genotype data were obtained from 133 idiopathic Parkinson's disease patients and 212 control subjects matched on age, gender and ethnicity. No statistically significant differences were found in the distribution of the reference and variant alleles between Parkinson's disease and control subjects, or when results were stratified by gender. Therefore, common polymorphisms within EPHX1 and EPHX2 do not appear to be important risk factors for Parkinson's disease.

Genetic polymorphisms of superoxide dismutase in Parkinson's disease.

Oxidative stress reactions may contribute to the pathogenesis of Parkinson's disease (PD). The superoxide dismutases potentially play significant roles in PD by detoxifying superoxide radical. We developed genomic DNA and cDNA-based sequencing assays to identify genetic variants in the copper/zinc superoxide dismutase (SOD1) and manganese superoxide dismutase (SOD2) genes. No genetic variants were detected in the gene encoding SOD1 in DNA from 45 idiopathic PD cases and 49 controls from a population-based case-control study. However, we identified a previously described polymorphism of the mitochondrial targeting sequence consisting of a C47T in exon 2 of SOD2, which results in an alanine to valine substitution. We analyzed this SOD2 variant in DNA from 155 cases and 231 controls from the same study, using an allele-specific fluorogenic 5' nuclease assay, and found no differences in the distributions of allelic frequencies. These results indicate that SOD gene variants do not contribute to PD pathogenesis.

A laminated, flex structure for electronic transport and hybridization of DNA.

We have developed the first prototypes of a three-dimensional, electrophoretically driven microlaboratory for the analysis of proteins and DNA. By selecting the appropriate spacing and geometrical configuration, oligonucleotides were transported, in a controlled, rapid fashion, by electrophoresis in free-space. Transport efficiencies over 2 mm distances exceeded 70%. Electrodes of similar design were combined with an electronically addressed DNA hybridization chip to form a fully electrophoretic microlaboratory. In this instance, gold-plated copper electrodes were patterned on a 2 mil thick polyimide substrate. This polyimide layer was stiffened with 20 mil of polyimide to provide support for flip-chip bonding of our standard 100-site Nanochip. This composite structure illustrated three-dimensional transport of target oligonucleotides, through a via in the polyimide, along a series of electrodes and onto the diagnostic chip. Upon reaching the diagnostic chip, electronic hybridization was performed for a competitive reverse dot blot assay. The electronic assay showed a specific to nonspecific ratio in excess of 20:1. These results suggested that this type of structure might be of practical consequence with the development of a microlaboratory for biowarfare applications.

Parkinson's disease, CYP2D6 polymorphism, and age.

OBJECTIVE: PD may be caused by genetic susceptibility to neurotoxins. CYP2D6 is a candidate gene for PD because it regulates drug and toxin metabolism, but association studies have been inconsistent. The aim of this study was to test if the CYP2D6*4 allele (poor metabolizer phenotype) is associated with earlier age at onset. METHODS: Five hundred seventy-six patients with PD and 247 subjects without PD were studied using standard diagnostic, genotyping, and statistical techniques. RESULTS: Surprisingly, mean onset age was significantly later in *4-positive patients. Frequency of *4 was significantly higher in late-onset PD than early-onset PD. When early- and late-onset PD were analyzed separately, *4 had no effect on onset age; hence, the association with delayed onset was likely an artifact of an elevated *4 frequency in late-onset PD. Contrary to a common assumption that CYP2D6 frequencies do not change with age, *4 frequency rose significantly with advancing age, both in patients with PD (from 0.16 at mean age of 56.5 years to 0.21 at mean age of 72) and subjects without PD (from 0.09 at mean age of 45.5 years to 0.21 at mean age of 72). *4 Frequencies in patients with early- and late-onset PD, although different from each other, were in agreement with similarly aged subjects without PD, suggesting the elevated *4 frequency in late-onset PD was likely an age effect, unrelated to PD. CONCLUSION: The CYP2D6*4 allele is not associated with earlier PD onset. *4 May be associated with survival. Inconsistent results from allelic association studies may have been due to an unrecognized age effect.

Mitochondrial ND1 sequence analysis and association of the T4216C mutation with Parkinson's disease.

Mitochondrial dysfunction originating from mutations in Complex I genes may play a role in the pathogenesis of Parkinson's disease (PD). In this study, the entire ND1 coding sequence was sequenced in 84 newly diagnosed PD cases and 127 age/gender-matched controls. Numerous missense mutations were found at low frequency (<5%), whereas a thymidine to cytosine missense mutation at position 4216 that results in the replacement of tyrosine with histidine was found in 25% of the PD case samples and in 18% of the controls. When calculated according to gender, the 4216 mutation was observed in 26% of the male cases versus 16% of male controls (Odds Ratio [OR] = 1.85; 95% CI = 0.79-4.34). In contrast, females exhibited approximately equal frequencies among cases (22.5%) and controls (21%), yielding an OR of 1.08 (95% C.I. = 0.36-3.22). The findings indicate only a weak association of this genetic variant with PD.

Genetic polymorphism of dopamine D2 receptors in Parkinson's disease and interactions with cigarette smoking and MAO-B intron 13 polymorphism.

Genetic polymorphisms of dopamine D2 receptors (DRD2) may be susceptibility factors for Parkinson's disease due to their influence on dopamine response and association with cigarette smoking, which is inversely related to risk of Parkinson's disease. Relations of TaqIA and TaqIB DRD2 genotypes with Parkinson's disease were investigated and tested for interactive effects with smoking and the monoamine oxidase B (MAO-B) intron 13 polymorphism previously found to be related to smoking. Study subjects were 152 cases of idiopathic Parkinson's disease and 231 controls. The smoking history of all genotyped subjects was known. Subjects of genotype B12 were more frequent among cases than controls (27% and 23.8%, respectively), and were more frequent among "ever smokers" than "never smokers", among controls (27.8% and 17.2%, respectively), although these associations were not statistically significant. Neither TaqIA or TaqIB genotypes modified the inverse relation of smoking and Parkinson's disease. When genotypes for DRD2 were considered in combination with genotypes for intron 13 of MAO-B, genotype combinations with high risk of Parkinson's disease were found; although the MAO-B/DRD2 interaction did not reach statistical significance after Bonferroni correction for multiple comparisons, these results are suggestive of a possible synergism between MAOB and DRD2 genes with respect to Parkinson's disease.

The EcoRV genetic polymorphism of human monoamine oxidase type A is not associated with Parkinson's disease and does not modify the effect of smoking on Parkinson's disease.

We previously observed an association with Parkinson's (PD), and modification of the effect of smoking on PD, by a polymorphism of the monoamine oxidase B (MAO-B) gene. The A form of monoamine oxidase (MAO-A) shares with MAO-B many characteristics that could be relevant to PD, especially proneuroxicant bioactivation and dopamine metabolism. MAO-A is also inhibited by tobacco smoke, which bears an apparent protective effect on PD. We investigated the possibility that MAO-A genetic variants may also be involved in predisposition to PD and in modification of the effect of smoking. Three-hundred and seventy-one subjects--145 idiopathic PD cases and 226 age/gender-matched controls--were genotyped for the EcoRV polymorphism of MAO-A gene which has been related to increased enzyme activity. MAO-A EcoRV polymorphism was neither significantly associated with PD nor did it modify the inverse relationship with smoking. These results suggest that the EcoRV polymorphism of MAO-A is not an important biomarker of PD risk.

Dietary factors in Parkinson's disease: the role of food groups and specific foods.

PURPOSE: The association between self-reported past food intake and Parkinson's disease (PD) was investigated in a case-control study of men and women aged 40-89 years. METHODS: Newly diagnosed idiopathic PD cases were ascertained from neurologists, and from outpatient and pharmacy computerized databases, at the Group Health Cooperative (GHC) clinics in the Puget Sound region of Washington state. Control subjects were chosen from the GHC patient roster and had no reported history of diagnosed neurodegenerative disease. Dietary data were obtained from structured questionnaires. RESULTS: An increase in PD risk with increasing intake was noted for foods that contain animal fat and foods containing vitamin D. Intake of fruits, vegetables, meats, bread and cereals, or foods containing vitamins A, C, E, or iron was not significantly related to PD risk. Vitamin use, in general, was also not found to be related to PD risk, although a significant trend of increasing risk of PD was noted for intake of vitamin A supplements. CONCLUSIONS: Although these data support previous findings of no association of past intake with most food groups and PD risk, they confirm an increased risk of PD associated with foods containing animal fat.

A genetic polymorphism of MAO-B modifies the association of cigarette smoking and Parkinson's disease.

In a population-based case-control study, we found a reversal of the association of cigarette smoking with Parkinson's disease (PD) in relation to the monoamine oxidase B intron 13 genetic polymorphism. A reduced PD risk related to pack-years of smoking was detected for persons with the G allele, whereas an opposite effect was found among persons with the A allele. These results indicate an unexplained interaction between cigarette smoking and this genetic polymorphism.

Association of a polymorphism in intron 13 of the monoamine oxidase B gene with Parkinson disease.

Monoamine oxidase B (MAO-B) is an enzyme that has relevance for Parkinson disease (PD) because of its roles in catabolizing dopamine and potentially activating exogenous neurotoxicants. A polymorphism of the gene encoding MAO-B has been identified as a single base change (A or G) in intron 13 of the X chromosome. The A allele was previously associated with an approximately twofold risk of PD. The present study compared A and G allele frequencies between newly diagnosed idiopathic PD cases and a control group free of neurodegenerative diseases. All study subjects were Caucasian. Cases were 37 men and 25 women, age 37-80 years; controls were 50 men and 29 women, age 45-82 years. MAO-B genotype was determined by the allele-specific polymerase chain reaction on DNA extracted from peripheral lymphocytes. In complete contrast to previous studies, elevated risks were detected with the G allele. The age-adjusted odds ratio for the G allele in males was 1.87 ((95% confidence interval) 0.78-4.47). Among females the age-adjusted odds ratios were 5.00 ((95% confidence interval) 1.13-22.1) for the GA genotype and 5.60 ((95% confidence interval) 1.01-30.9) for the GG genotype. These findings, although of limited statistical precision, suggest that the G allele of this MAO-B polymorphism may relate to PD risk.

Selegiline and lymphocyte superoxide dismutase activities in Parkinson's disease.

Superoxide dismutases (SODs) are metalloenzymes that detoxify superoxide radicals, and occur in cytosolic (Cu,Zn-SOD) and mitochondrial (Mn-SOD) forms in multiple tissues, including brain. A neuroprotective effect against oxide stressor exposures may be provided by SOD, although excessive enzyme activity can produce cell injury by formation of hydroxyl radical from hydrogen peroxide. We measured Cu,Zn-SOD and Mn-SOD activities in peripheral lymphocytes of 43 newly diagnosed idiopathic Parkinson's disease (PD) cases and 62 age- and sex-matched controls free of neurodegenerative disorders. Significant excesses of both SOD forms were found among PD cases compared with controls; however, the excesses were found exclusively among PD patients treated with the monoamine oxidase inhibitor selegiline (L-deprenyl). Enzyme-linked immunosorbent assays (ELISAs) confirmed that the activity excesses were due to increased protein rather than more highly reactive enzymes in lymphocytes of PD cases. Our findings clearly indicate the importance of selegiline on measured Cu,Zn-SOD and Mn-SOD activity in peripheral lymphocytes. Characterizing a possible therapeutic value of SOD will require longitudinal assessments of SOD in relation to PD progression.

Diagnosis of inherited metabolic disorders affecting the nervous system.

Knowledge of the molecular causes for genetic diseases that affect the nervous system is rapidly expanding. Especially striking has been the finding in several autosomal dominant neurodegenerative disorders that unstable expansions of trinucleotide repeats are responsible for the genetic disorder and that the length of the repeat can be correlated with the age of onset and the severity of symptoms. Phenotypic heterogeneity in many disorders associated with enzyme deficiencies can often be linked to the amount of residual enzyme activity occurring with different gene mutations. Making a specific diagnosis of a neurological disorder associated with genetically determined metabolic defects requires access to a laboratory that can assist in arranging for appropriate testing to be carried out. In some disorders such as the aminoacidurias diagnostic metabolic studies can be performed in hospital clinical chemistry laboratories. In others, such as the lysosomal storage diseases, a laboratory that carries out special lipid analyses and white blood cell enzyme assays will be necessary. DNA mutational analyses are becoming commercially available for diagnosing many disorders such as mitochondrial diseases and those conditions associated with expanded trinucleotide repeats. It may be necessary to contact individual research laboratories when confronted with a disorder that has been newly discovered or that is very rare. A computerised directory of specialised laboratories that perform disease specific testing for genetic disorders should be useful in choosing the appropriate diagnostic or research laboratory.

Intraventricular fat from a ruptured sacral dermoid cyst: clinical, radiographic, and pathological correlation. Case report.

The authors report a unique case of a dermoid cyst that ruptured into the lumbosacral subarachnoid space following trauma, resulting in dissemination of cyst contents into the ventricles and cerebrospinal subarachnoid spaces. An intraspinous source should be considered when intraventricular fat is identified without a clear intracranial source.

DNA deletion associated with hereditary neuropathy with liability to pressure palsies.

Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal dominant disorder that causes episodes of focal demyelinating neuropathy following minor trauma to peripheral nerves. We assign the HNPP locus to chromosome 17p11.2 and demonstrate the presence of a large interstitial deletion associated with this disorder in three unrelated pedigrees. De novo deletion is documented in one pedigree. The deleted region appears uniform in all pedigrees and includes the gene for peripheral myelin protein 22 (PMP-22), suggesting that underexpression of PMP-22 may cause HNPP. The deletion in HNPP spans approximately 1.5 Mb and includes all markers that are known to map within the Charcot-Marie-Tooth neuropathy type 1A (CMT1A) duplication. Furthermore, the breakpoints in HNPP and CMT1A map to the same intervals in 17p11.2, suggesting that these genetic disorders may be the result of reciprocal products of unequal crossover.