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Biomedical subjects

S Fahn

Publications and source records attributed to S Fahn.

At least 145 records · Page 8Linked to original sources
PubMed1993

Striatal 18F-dopa uptake: absence of an aging effect.

L-[18F]6-Fluoro-DOPA (L-[18F]6-fluoro-3,4-dihydroxyphenylalanine; FDOPA) has been used with quantitative positron emission tomography (PET) to assess presynaptic nigrostriatal dopaminergic function in life. The relationship of estimated kinetic rate constants for striatal FDOPA uptake [Ki(FDOPA)] to the normal aging process has been the subject of conflicting reports. Resolution of this issue has been hampered by methodological differences in previous FDOPA/PET investigations. We studied 19 healthy normal subjects (aged 27-77 years) and measured striatal Ki-(FDOPA) according to each of the earlier methods. While significant correlations (p < 0.005) existed between Ki(FDOPA) values estimated by the various techniques, none correlated with normal aging. We conclude that normal striatal Ki(FDOPA) values estimated using quantitative FDOPA/PET are uncorrelated with the aging process.

Adult↗
PubMed1993

Linkage mapping of dopa-responsive dystonia (DRD) to chromosome 14q.

Dopa-responsive dystonia (DRD) is an autosomal-dominant neurological disorder which appears to result from a genetically determined deficiency of striatal dopamine. Pathological evidence suggests that this may be due to the establishment of a reduced number of dopaminergic nerve terminals in the striatum, or to an excessive reduction (pruning) of these terminals in early development. We have mapped the DRD gene to chromosome 14 by linkage analysis in 3 families with a maximum 2-point lod score of 4.67 at 8.6 centiMorgans from D14S63; maximum multipoint lod scores > 6 were obtained for the intervals D14S47-D14S52 and D14S52-D14S63. The flanking loci D14S47 and D14S63 define a region of about 22 cM as containing the DRD gene.

Chromosome Mapping↗
PubMed1993

Dominantly inherited, early-onset parkinsonism: neuropathology of a new form.

We report postmortem findings in a 46-year-old man with dominantly inherited parkinsonism whose symptoms started at age 28. At least 13 other family members in three generations have been affected, some from early childhood. Dystonia is a prominent feature in several of the youngest patients, but was not present in this patient. After several years of successful treatment with medication, he developed severe on-off fluctuations and dyskinesias. At age 45, the patient underwent stereotaxic implantation of autologous adrenal medullary tissue into the left corpus striatum and lateral ventricle. He improved considerably over the following 6 months, but then developed glioblastoma multiforme and died 1 year after transplantation. There was severe neuronal loss in the pars compacta and pars reticulata of the substantia nigra, with prominent gliosis in the pars reticulata. The nigral neurons remaining in the pars compacta were poorly pigmented. Neither Lewy bodies nor neurofibrillary tangles were present, and we identified no other degenerative neuropathologic changes. This combination of pathologic and clinical features differs from any previously reported case.

Adult↗
PubMed1993

Phenotypic expression of X-linked dystonia-parkinsonism (lubag) in two women.

Lubag (X-linked dystonia-parkinsonism) has been considered a sex-linked recessive trait and has been mapped to the pericentromeric region of the X chromosome. We studied a 54-year-old man with lubag and two of his female first cousins. Genetic typing was carried out using X chromosome markers. Fluorodopa PET was performed on the man and one of the women. The man had moderately severe parkinsonism and dystonia. A 61-year-old female first cousin had mild left-sided dystonia and her 54-year-old sister had mild generalized chorea. Genetic typing data revealed that all three inherited an X chromosome with marker alleles strongly associated with lubag. Cytologic analysis did not reveal evidence of X chromosomal deletion. Fluorodopa PET in both the man and one affected cousin revealed reduced striatal uptake rate constants consistent with nigrostriatal involvement. These observations suggest that lubag may be a codominant disorder and that it is possible for women to be affected.

Alleles↗
PubMed1992

Long-term treatment response and fluorodopa positron emission tomographic scanning of parkinsonism in a family with dopa-responsive dystonia.

Dopa-responsive dystonia (DRD) is one form of childhood-onset idiopathic torsion dystonia. Adult-onset parkinsonism has appeared in several previously unaffected members in families with DRD suggesting that this may be an additional phenotypical expression of the disease. We report a family with DRD in which 2 women and 1 man, unaffected by dystonia, developed tremor-onset parkinsonism after age 50 years. The women continue on a low dosage of levodopa after 9 and 13 years of treatment, with a stable, nearly complete, symptomatic response. This contrasts to the typical long-term treatment complications observed in patients with Parkinson's disease. We assessed nigrostriatal dopaminergic function in the proband, with typical DRD, and the 2 women with parkinsonism using 6-[18F]fluoro-L-dopa positron emission tomography. All 3 had normal striatal 6-[18F]fluoro-L-dopa uptake. These observations provide compelling evidence that "benign" adult-onset parkinsonism may be an expression of the disease in some members of families with DRD and does not support consideration of the DRD gene as a risk factor for development of Parkinson's disease. There may be considerable clinical heterogeneity in DRD depending on the age at onset.

Adult↗
PubMed1992

The oxidant stress hypothesis in Parkinson's disease: evidence supporting it.

Oxidant stress, due to the formation of hydrogen peroxide and oxygen-derived free radicals, can cause cell damage due to chain reactions of membrane lipid peroxidation. Because the substantia nigra is rich in dopamine, which can undergo both enzymatic oxidation via monoamine oxidase and nonenzymatic autoxidation, hydrogen peroxide and oxyradicals (superoxide anion radical and hydroxyl radical) are generated in this midbrain nucleus. Although proof that oxidant stress actually causes the loss of monoaminergic neurons in patients with Parkinson's disease is lacking, there is a considerable body of evidence from studies in both animals and humans that support the concept. (1) Neurotoxins that selectively destroy the dopaminergic neurons in the nigra, such as 6-hydroxydopamine and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), appear to act via oxidant stress. (2) The substantia nigra of patients with Parkinson's disease reveals evidence of oxidant stress by the findings of increased lipid peroxidation and decreased reduced glutathione. (3) Total iron is increased and ferritin is reduced in the substantia nigra pars compacta in patients with Parkinson's disease. This combination suggests that this transition metal is in a low molecular weight form, capable of catalyzing nonenzymatic oxidative reactions, especially the conversion of hydrogen peroxide to hydroxyl radical, which is the most reactive of the oxygen radicals. (4) Neuromelanin, a product of dopamine autoxidation, can serve as a reservoir for iron, promoting the generation of oxyradicals. (5) Antioxidant defense mechanisms appear to be reduced in the parkinsonian substantia nigra with the findings of decreased activities of glutathione peroxidase and catalase.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

A pilot trial of high-dose alpha-tocopherol and ascorbate in early Parkinson's disease.

High dosages of a combination of alpha-tocopherol and ascorbate were administered to patients with early Parkinson's disease as an open-labeled trial and pilot study to test the endogenous toxic hypothesis of the etiology of Parkinson's disease. Patients receiving concomitant amantadine and anticholinergics were allowed to participate, but those receiving levodopa or dopamine agonists were not. The study was begun prior to the availability of deprenyl. The primary end point of the trial was progression of the disease until patients needed treatment with levodopa or a dopamine agonist. The time when levodopa became necessary in the treated patients was compared to another group of patients followed elsewhere who did not receive antioxidants. The time when levodopa became necessary was extended by 2.5 years in the group receiving alpha-tocopherol and ascorbate. Results of this pilot study suggest that the progression of Parkinson's disease may be slowed by administration of these antioxidants. Controlled clinical trials using double-blind randomization techniques are required to confirm these results.

Adult↗
PubMed1992

Neurotoxicity of levodopa on catecholamine-rich neurons.

The human neuroblastoma cells NB69 are a catecholamine-rich cell line with pharmacological properties similar to dopamine neurons. This cell line was used to study the neurotoxicity of levodopa on catecholamine neurons. Levodopa, at 50 x 10(-6) M or higher concentrations, produced a dose- and time-dependent reduction in the number of live cells, [3H]thymidine uptake, levels of protein and DNA, and an enhancement of the quinone formation. This is a specific effect of levodopa since it did not happen in NB69 cells incubated with equimolar concentrations of leucine and tryptophan. Treatment with deprenyl, an inhibitor of monoamine oxidase type B, partially prevented levodopa neurotoxicity, suggesting that the mechanism of toxicity was, at least in part, related to an increase in the metabolism of dopamine catalyzed by monoamine oxidase.

Catecholamines↗
PubMed1992

Baclofen in the treatment of idiopathic dystonia in children.

Baclofen benefits some patients with adult onset dystonia, but few reports document the response to baclofen of children with idiopathic dystonia. Sixteen of 80 patients less than age 21 years with idiopathic dystonia seen by the Movement Disorder Group at Columbia-Presbyterian Medical Center in New York were treated with baclofen. Five had substantial improvement in symptoms, two had moderate improvement, and nine failed to benefit. Three of the improved patients had transient improvement on high dose anticholinergics, but had sustained, dramatic improvement when baclofen was added. At last follow-up, five patients maintained improvement for a mean 3.8 years (19 months-8 years) on a mean 79 mg of baclofen (40-120 mg). Response to baclofen did not correlate with age at onset of dystonia or age at onset of therapy, but did correlate with duration of symptoms before therapy (3 years for those who improved vs 7.8 years for those who did not: p less than .002 by t-test). Baclofen can be an effective treatment for childhood dystonia.

Adolescent↗
PubMed1992

Cerebrospinal fluid antibodies to coronavirus in patients with Parkinson's disease.

The etiology of Parkinson's disease remains unknown, and a search for environmental agents continues. In 1985, Fishman induced infection of the basal ganglia by a coronavirus in mice. Although coronavirus is recognized primarily as a respiratory pathogen in humans, its affinity for the basal ganglia led us to investigate its possible role in human Parkinson's disease. The cerebrospinal fluid of normal controls (CTL) (n = 18), and patients with Parkinson's disease (PD (n = 20) and other neurological disease (OND) (n = 29) was analyzed in a blinded manner by enzyme-linked immunosorbent assay [measurements in optical density (OD) units] for antibody response to four coronavirus antigens: mouse hepatitis virus JHM (J) and A59 (A), and human coronavirus 229E (E) and OC43 (O). When compared with CTL, PD patients had an elevated (p less than 0.05) mean OD response to J (0.0856 vs. 0.0207) and A (0.1722 vs. 0.0636). Response (p greater than 0.05) to O (0.0839 vs. 0.0071) was greater than that to E (0.1261 vs. 0.0743). When compared to OND, PD patients had an elevated mean OD response to J (0.0856 vs. 0.0267, p less than 0.05). Responses (p greater than 0.05) to A (0.1722 vs. 0.0929) and O (0.0839 vs. 0.0446) were greater than that to E (0.1261 vs. 0.0946). These results suggest that there may be an association between coronavirus and PD.

Antibodies, Viral↗
PubMed1992

Implantation of genetically modified mesencephalic fetal cells into the rat striatum.

Transplantation of dopamine (DA) cells into the rat model of hemiparkinsonism induced by intranigral 6-hydroxydopamine (6-OHDA) injections has so far focused mainly on DA replacement via a pump-like mechanism. In the present study, we employed a model of hemiparkinsonism that uses an intrastriatal approach to lesioning the nigrostriatal DA pathway to assess the possibility of using cell transplantation to cause regeneration of that system. Toward that end, we transplanted two types of cells on the side of the 6-OHDA-induced lesions: 1) nonmodified fetal mesencephalic cells and 2) fetal mesencephalic cells that have been infected with a retrovirus vector containing a PKC beta 1 cDNA. Both types of cells cause behavioral improvement although the changes were more prominent and occurred earlier in the PKC-modified groups. Tyrosine hydroxylase (TH) immunocytochemistry revealed significantly cell survival in both groups of animals; in situ hybridization studies confirmed the continuous expression of TH mRNA in both groups. Interestingly, long TH-positive axons were observed only in the striata of animals implanted with PKC-modified cells. More importantly, surviving endogenous nigral TH-positive cell bodies were found only on the lesioned side in the latter group. The observations in these animals were associated with significantly smaller decreases in [3H]mazindol-labeled DA uptake sites in both the striata and substantia nigra pars compacta on the side ipsilateral to the 6-OHDA-induced lesions. Furthermore, immunohistochemical studies revealed increased gliosis in the striata of animals grafted with the PKC-modified cells. When taken together, these results indicate that transplantation of normal fetal mesencephalic cells can cause behavioral improvement by providing DA to the host striata whereas PKC-modified cells can, in addition, prevent the progressive degeneration of or cause regeneration of the dying nigrostriatal DA neurons in this model of hemiparkinsonism. These results are discussed in terms of their support for a role for second messenger systems and glial cells, as well as extracellular matrix molecules in the regeneration of the CNS.

Amphetamine↗