Effective thalamic deep brain stimulation for neuropathic tremor in a patient with severe demyelinating neuropathy

Postural and action tremor in peripheral neuropathy is characteristic of Roussy-Levy syndrome. A patient with a severe demyelinating neuropathy and disabling neuropathic tremor successfully treated by deep brain stimulation (DBS) is reported. Disease onset was at age 63 years with sensory symptoms and slight action tremor. Within the following 9 years a severe, drug resistant, postural and action tremor developed rendering the patient unable to feed himself. At age 72 years the patient was treated by bilateral DBS of the ventral intermediate thalamic nucleus, with a useful 30% reduction in tremor. The clinical benefit of the stimulation remained stable over a 1 year postoperative observation period.

Does Contrast Medium Administration in Organ Donors Affect Early Kidney Graft Function?

Since the upper age for organ donors has been raised, a higher incidence of preexistent organ damage and functional impairment is to be expected. Coronary artery sclerosis increases with age. It can only be diagnosed with certainty by coronary angiography. Since contrast medium administration may cause renal damage when risk factors are present, this study sought to establish whether angiography negatively influenced the early postoperative function of kidney grafts. We compared the clinical courses of 36 recipients of kidneys from donors in whom coronary angiography or levography had been performed with 36 recipients of kidneys from donors who had not been subjected to contrast medium. The results showed that the administration of contrast medium had no influence on renal function at 3 or 6 months after transplantation. In conclusion, fears that donor kidneys might be harmed by contrast medium appeared to therefore be unfounded.

Genetic causes of Parkinson's disease: extending the pathway

The functional characterization of identified disease genes in monogenic forms of Parkinson's disease (PD) allows first insights into molecular pathways leading to neurodegeneration and dysfunction of the nigrostriatal system. There is increasing evidence that disturbance of the ubiquitin proteasome pathway is one important feature of this process underscoring the relevance of protein misfolding and accumulation in the neurodegenerative process of PD. Other genes are involved in mitochondrial homeostasis and still others link newly identified signalling pathways to the established paradigm of oxidative stress in PD. Additional factors are posttranslational modifications of key proteins such as phosphorylation. Also, molecular data support the role of altered iron metabolism in PD. Here we describe known genes and novel genetic susceptibility factors and define their role in neurodegeneration.

[Treatment results after surgery for basal cell carcinomas of the head and neck region taking into consideration various reconstruction techniques]

BACKGROUND

Basal cell carcinomas are the most frequently occurring malignant tumors in the white population. They exhibit a multitude of histological/morphological forms.

PATIENTS AND METHOD

All cases of basal cell carcinoma treated at the department for oral and maxillofacial and regional plastic surgery of the HELIOS hospital in Erfurt between 1976 and 2003 were analyzed and partly reexamined in a retrospective study.

RESULTS

A total of 648 patients with 765 basal cell carcinomas were treated. Occurrences in females dominated those in males with a frequency distribution of 1.24:1. The average age was 70.6 years with a significantly larger number of female seniors above 60. In 64% of the cases the basal cell carcinomas were nodular, in 16% infiltrative. Other morphological/histological forms occurred with a frequency of <or=5%. The most frequent localizations were in of the regions of the highest sun exposure such as the nose, midface, and forehead.

DISCUSSION

If an infiltrative basal cell carcinoma is suspected or insufficient radical primary surgery is presumed, plastic reconstruction should be postponed until free margins can be confirmed histologically. The functional and aesthetic quality of reconstruction was better using pedicled flaps (90%) and primary closure (86%) than using free skin transplants (30-54%). Nevertheless, free skin flaps and epitheses were found to be well accepted by the reexamined patients.

The role of alpha-synuclein gene multiplications in early-onset Parkinson's disease and dementia with Lewy bodies

BACKGROUND

A triplication of the alpha-synuclein gene was found to cause autosomal dominant Lewy body disease in two distinct families.

METHOD

We searched for alterations of alpha-synuclein gene dosage and analysed the entire coding region for point mutations in 54 dementia with Lewy body disease (DLB) and in 103 young onset Parkinson's disease (PD) patients from Central Europe.

RESULTS

We could not detect any quantitative alterations in the gene dosage of alpha-synuclein. Mutational screening of the entire coding region of alpha-synuclein revealed only one silent mutation V3V (adenine9guanine) in one case.

CONCLUSIONS

Thus, this phenomenon appears not to be a major cause in the pathogenesis of sporadic DLB and young onset PD in this European population.

Antiapoptotic effects of budipine

Apoptosis is one essential step for neuronal death in the nigrostriatal region in patients with Parkinson's disease. Cytotoxic tumor necrosis factor-alpha (TNF-alpha) and the proinflammatory cytokine interleukin-6 (Il-6) provide a proapoptotic environment. We investigated the influence of the antiparkinsonian compound budipine on the release of TNF-alpha and Il-6 in peripheral blood mononuclear cells (PBMC) and on the degree of cisplatin induced apoptotic cell death in SH-SY 5Y human neuroblastoma cells. 10(-7), 10(-8), 10(-9) mol/l of budipine significantly reduced release of TNF-alpha and Il-6 in PBMC and decreased apoptotic cell death after 50 hours and 74 hours in the SH-SY 5Y cells. Our results suggest, that budipine administration provides an antiapoptotic environment and slows neuronal apoptotic and inflammatory mediated loss of neurons.

Screening for mutations in synaptotagmin XI in Parkinson's disease

Parkinson's disease (PD) is characterized by selective degeneration of neurons in the substantia nigra and subsequent dysfunction of dopaminergic neurotransmission. Genes identified in familial forms of PD encode proteins that are linked to the ubiquitin-proteasome system indicating the pathogenic relevance of disturbed protein degradation in PD. Some of them, i.e. alpha-synuclein, parkin and synphilin-1, have been implicated in presynaptic neurotransmission based on their localization in synaptic vesicles. Synaptotagmin XI is linked to the pathogenesis of PD based on its identification as a substrate of the ubiquitin-E3-ligase parkin. Moreover synaptotagmin XI is involved in the maintainance of synaptic function and represents a component of Lewy bodies (LB) in brains of PD patients. Therefore, we performed a detailed mutation analysis of the synaptotagmin XI gene in a large sample of 393 familial and sporadic PD patients. We did not find any disease causing mutations arguing against a major role of mutations in the synaptotagmin XI gene in the pathogenesis of PD.

Orbital ordering in LaMnO3 investigated by resonance Raman spectroscopy

Orbital ordering leads to an unconventional excitation spectrum that we investigate by resonance Raman scattering using incident photon energies between 1.7 and 5.0 eV. We use spectral ellipsometry to determine the corresponding dielectric function. Our results show resonant behavior of the phonon Raman cross section when the laser frequency is close to the orbiton-excitation energy of 2 eV in LaMnO3. We show an excellent agreement between theoretical calculations based on the Franck-Condon mechanism activating multiphonon Raman scattering in first order of the electron-phonon coupling and the experimental data of phonons with different symmetries.

Giant cavernoma of the brain stem: value of delayed MR imaging after contrast injection

Cavernous angiomas are vascular malformations composed of slowly perfused, sinusoidal vessels which can be located in any part of the central nervous system. Whereas diagnosis is mostly straightforward in typical cases, some lesions may present in unusual locations or with unusual imaging characteristics. Because of the slow perfusion, contrast enhancement is not regarded as a characteristic imaging feature of cavernomas. We report a large brain stem cavernoma with signs of recent bleeding, in which the differential diagnosis against other mass lesions was facilitated by the demonstration of slow, but intense, contrast enhancement on MRI 1 h after contrast injection. We conclude that contrast enhancement in delayed images may contribute to a safe diagnosis of cavernous haemangiomas and should be performed in atypical cases.

Modulation of disease risk according to a cathepsin D / apolipoprotein E genotype in Parkinson's disease

Aspartyl protease Cathepsin D (CTSD) has been suggested to play a role in the pathogenesis of sporadic Alzheimer's disease (AD) due to interference with protein degradation mechanisms. A C224T (A38V) polymorphism in exon 2 of the CTSD gene is reported to be associated with an increased risk for AD. The partially overlapping pathology between AD and Parkinson's disease (PD) led us to investigate the role of this polymorphism in PD. Using association studies in 457 German PD patients and 340 controls we found no evidence for direct association between the CTSD genotype and PD. However, stratification for the apolipoprotein E (APOE) epsilon4 allele suggests a protective effect of the CTSD T-allele in PD (OR = 0.24, p = 0.002). Our findings suggest interference of CTSD and APOE polymorphisms in the pathogenesis of PD, in the sense of modulating disease risk.

Giant cavernoma of the brain stem: value of delayed MR imaging after contrast injection

Cavernous angiomas are vascular malformations composed of slowly perfused, sinusoidal vessels which can be located in any part of the central nervous system. Whereas diagnosis is mostly straightforward in typical cases, some lesions may present in unusual locations or with unusual imaging characteristics. Because of the slow perfusion, contrast enhancement is not regarded as a characteristic imaging feature of cavernomas. We report a large brain stem cavernoma with signs of recent bleeding, in which the differential diagnosis against other mass lesions was facilitated by the demonstration of slow, but intense, contrast enhancement on MRI 1 h after contrast injection. We conclude that contrast enhancement in delayed images may contribute to a safe diagnosis of cavernous haemangiomas and should be performed in atypical cases.

Polymorphisms of the alpha-synuclein promoter: expression analyses and association studies in Parkinson's disease

Mutations of the alpha-synuclein gene have shown to be relevant in some rare families with autosomal dominant Parkinson's disease (PD). Furthermore, alpha-synuclein protein is a major component of the Lewy bodies also in sporadic PD patients. Increased levels of wildtype alpha-synuclein in the cell leads to increased intracellular hydrogen peroxide levels and causes death of dopaminergic neurons in rat primary culture. Subsequently, oxidative stress has been directly linked with alpha-synuclein aggregation in vitro. This raises the question whether increased alpha-synuclein expression might be linked to higher susceptibility to PD and whether alpha-synuclein promoter polymorphisms are associated with PD. Here, two polymorphisms (-116C>G and -668T>C) of the alpha-synuclein promoter defining four haplotypes have been characterized in 315 German PD patients. The influence of the four haplotypes on gene expression was studied by CAT reporter gene assays in neuronal SK-N-AS cells. The -668C/-116G haplotype revealed significant higher CAT expression than the -668T/-116G or the -668T/-116C haplotype, respectively. Although the -668C/-116G haplotype was more common in PD patients, this difference was not significant.

Mutation analysis and association studies of nuclear factor-kappaB1 in sporadic Parkinson's disease patients

Biochemical and morphological studies revealed that oxidative stress and apoptosis play a role in neurodegeneration in Parkinson's disease (PD). Reactive oxygen species may be directly involved in apoptosis or via upregulation of toxic cytokines, i.e. tumor necrosis factor alpha (TNFalpha). We recently demonstrated that the TNFalpha pathway contributes to the pathogenesis of sporadic PD using a genetic approach. These signalling pathways converge to the transcription factor nuclear factor kappaB (NF-kappaB), which has been found activated in affected neurons in PD. We performed a detailed mutation analysis of the p50 subunit of NF-kappaB (NFKB1 gene) in 96 sporadic PD patients. Previously, positive association was demonstrated in this cohort to chromosome 4q21-23 containing the NFKB1 gene. We identified three base exchanges not affecting the amino acid sequence, which were found at similar frequencies in controls. Our study does not support a genetically definable role of NFKB1 in the pathogenesis of sporadic PD.

Analyte incorporation and ionization in matrix-assisted laser desorption/ionization visualized by pH indicator molecular probes

Despite the spreading applications of matrix-assisted laser desorption/ionization (MALDI), its fundamental understanding is still limited and under constant debate. This report focuses on the initial state of the analyte in the host matrix. pH indicator dyes serve as molecular probes since their color directly indicates their (de)protonation state. For a set of matrixes at their intrinsic pH, solution color was maintained, delivering clear proof for analyte incorporation in the solution charge state. Moreover, substantial solvent inclusion is determined by 1H NMR spectroscopy. MALDI mass spectra show a clear correlation to the dye charge state. However, the dominant solution species are not observed exclusively in the mass spectra, pointing to a proton transfer or proton neutralization activity of the matrix.

Evaluation of the gamma-synuclein gene in German Parkinson's disease patients

Mutations in the alpha-synuclein gene are responsible for an autosomal-dominantly inherited form of Parkinson's disease (PD) and alpha-synuclein was found to be the major component of Lewy bodies in PD. Because of the high homology to alpha-synuclein and the abundance in neuronal tissues, we investigated the gamma-synuclein gene in PD. We analyzed 262 German PD patients and 179 healthy German controls via two polymorphisms in the gamma-synuclein gene. No significant differences in the allelic or genotypic distributions of the investigated polymorphisms were observed between patients and controls. In addition no evidence for an increased risk of combined genotypes of polymorphisms in the gamma-synuclein and the alpha-synuclein gene was found. Therefore, our results do not support a major role of the gamma-synuclein gene in PD.

Familial parkinsonism with synuclein pathology: Clinical and PET studies of A30P mutation carriers

BACKGROUND

The authors identified the second known mutation in the alpha-synuclein(SNCA) gene, an alanine-to-proline exchange in amino acid position 30 (A30P), that cosegregates with the disease in one German family with autosomal dominantly inherited parkinsonism (ADP). The authors studied carriers of the A30P mutation to compare the phenotype of this mutation with idiopathic PD (IPD) and to assess nigrostriatal dopaminergic function in symptomatic and preclinical mutation carriers.

METHODS

The pedigree of the A30P family spans five generations with five affected individuals. The authors performed detailed neurologic examinations followed by mutation analysis in 11 living individuals. In three mutation carriers, two individuals with definite PD and one person at risk for PD, they used L-[18]F-fluoro-3,4-dihydroxyphenylalanine (F-DOPA), [11]C-raclopride (RAC), and [18]F-fluorodeoxyglucose (FDG) PET to investigate presynaptic dopaminergic function, dopamine D2 receptors, and cerebral energy metabolism. The authors studied the cognitive functions of carriers of the A30P mutation using neuropsychological screening.

RESULTS

PET studies revealed striatal presynaptic dopaminergic alterations consistent with sporadic IPD in two affected family members and no evidence for nigrostriatal dopaminergic dysfunction in one presymptomatic mutation carrier. Neuropsychological testing in four mutation carriers provided evidence for cognitive impairment as a frequent and early symptom of the A30P mutation; this is also supported by regional cerebral energy metabolism alterations in the clinically presymptomatic subject.

CONCLUSIONS

The phenotype of the A30P mutation in the SNCA gene is similar to that of sporadic IPD, including a high variability of the age at disease onset, ranging from 54 to 76 years. The follow-up of presymptomatic carriers of the A30P mutation may give insight into preclinical disease stages and early manifestations of PD.

Monomer/dimer ratios of replication protein modulate the DNA strand-opening in a replication origin

DNA opening is an essential step in the initiation of replication via the Cairns mode of replication. The opening reaction was investigated in a gamma ori system by using hyperactive variants of plasmid R6K-encoded initiator protein, pi. Reactivity to KMnO4 (indicative of opening) within gamma ori DNA occurred in both strands of a superhelical template upon the combined addition of wt pi, DnaA and integration host factor (IHF), each protein known to specifically bind gamma ori. IHF, examined singly, enhanced reactivity to KMnO4. The IHF-dependent reactive residues, however, are distinct from those dependent on pi (wt and hyperactive variants). Remarkably, the DNA helix opening does not require IHF and/or DnaA when hyperactive variants of pi were used instead of wt protein. We present three lines of evidence consistent with the hypothesis that DNA strand separation is facilitated by pi monomers despite the fact that both monomers and dimers of the protein can bind to iterons (pi binding sites). Taken together, our data suggest that pi elicits its ability to modulate plasmid copy number at the DNA helix-opening step.

Genetic analysis of immunomodulating factors in sporadic Parkinson's disease

Immunomodulating factors have been shown to play a role in the pathogenesis of Parkinson's disease (PD) by biochemical methods. In order to investigate functionally important genes of the tumor necrosis factor alpha (TNFalpha) pathway we studied the frequency of DNA polymorphisms in the interleukin 6 (IL6), the TNFalpha, and the TNFalpha receptor 1 (TNFR1) genes in 264 sporadic German PD patients and in 183 age and sex matched German healthy controls. Analyzing the TNFalpha-308 polymorphism we found heterozygous individuals carrying alleles 1 and 2 more frequently in patients with a relative risk of 1.56 (p = 0.046, p(c) = 0.13, chi2 = 3.98). In contrast, the frequency of the B/2 haplotype described by the TNFR1-609 and TNFRI+36 polymorphisms was significantly decreased in our PD patients group (p = 0.0097, p(c) = 0.048, chi2 = 6.69) with a relative risk reduced to 0.52. Our results suggest an involvement of immunomodulating factors in the pathogenesis of sporadic PD as revealed by a molecular genetic approach.

Extrapyramidal motor signs in degenerative ataxias

BACKGROUND

Extrapyramidal motor signs (EPS) are well-known symptoms of degenerative ataxia. However, little is known about frequency and appearance of EPS in subtypes of ataxia.

METHODS

We characterized 311 patients with ataxia clinically and genetically. Course of the disease and EPS were investigated according to a standardized protocol. Diagnostic and prognostic impact of EPS in subtypes of ataxia was analyzed by Kaplan-Meier plots.

RESULTS

Extrapyramidal motor signs occurred in all forms of ataxia, but frequency and type of EPS varied between genetically and clinically defined subtypes. Postural tremor in hereditary ataxias was typical for spinocerebellar ataxia type 2 (SCA2). Dystonia was generally rare in ataxias, but, if present, suggested SCA3. We observed a parkinsonian variant of SCA3 in which parkinsonism was present in the beginning of the disease and responded well to levodopa therapy, leading to diagnostic confusion. Parkinsonism in SCA3 was independent of CAG repeat length but ran in families, suggesting modifying genes. In idiopathic sporadic cerebellar ataxia (ISCA), EPS are more frequent in late-onset than in early-onset forms. In 50% of ISCA patients with parkinsonism, the diagnosis of multiple system atrophy remained questionable because of normal autonomic function.

CONCLUSIONS

Extrapyramidal motor signs can help to predict the genetic subtype of ataxia. Extrapyramidal motor signs were more frequent in genetic subtypes in which basal ganglia affection has been demonstrated by postmortem studies. However, no type of EPS was specific for an underlying mutation. In ISCA, EPS are an adverse prognostic factor. Parkinsonism is especially associated with a more rapid course of the disease. Arch Neurol. 2000;57:1495-1500

The alpha1-antichymotrypsin A-allele in German Parkinson disease patients

An increased frequency of the A-allele of the alpha-antichymotrypsin (ACT) gene has been recently described in Japanese patients suffering from Parkinson disease (PD). In the present study, we have analyzed 62 German PD patients with regard to their ACT and APOE genotypes and compared them to 53 controls without clinical or pathological evidence of neurodegenerative disease. The A-allele frequency was 47% in PD patients compared to 54% in control cases excluding ACT as a major susceptibility factor for PD in the Caucasian population. Yet, ACT-A allele frequencies were significantly different (p < 0.001) between Japanese and German controls. Therefore, although our data do not suggest that the alpha1-ACT polymorphism is a significant risk factor for the development of PD, a consideration of differences in genetic background seems warranted when evaluating susceptibility factors for neurodegenerative disease.

Genetic analysis of the alpha2-macroglobulin gene in early- and late-onset Parkinson's disease

Recent association studies investigating polymorphisms in the alpha2-macroglobulin (A2M) gene provided evidence for an involvement of this protease inhibitor in the pathogenesis of Alzheimer's disease (AD). The partially overlapping pathology between AD and Parkinson's disease (PD) led us to investigate the role of A2M in PD. We performed association studies in a large sample of 328 German PD patients and 322 closely matched healthy controls. Analyzing the Val1000Ile polymorphism and a pentanucleotide deletion in the 5' splice site of exon 18 of the A2M gene we found an excess of homozygosity for the A2M deletion in early-onset PD (EOPD) patients (age at onset < 50 years) compared to late-onset PD (LOPD) patients (age at onset > 50 years; p = 0.008, p(p)c = 0.064, chi2 = 7.017). Therefore our data might indicate an age at onset modulating effect of the homozygous A2M deletion in PD.

Involvement of alpha-synuclein in Parkinson's disease and other neurodegenerative disorders

A major step in the elucidation of the pathogenesis of neurodegenerative disorders was the identification of a mutation in the alpha-synuclein gene in autosomal dominant Parkinson's disease (PD). Alpha-synuclein is the main component of Lewy bodies (LB), the neuropathological hallmark of PD. Moreover, a fragment of alpha-synuclein (NAC) is the second major component of amyloid plaques in Alzheimer's disease (AD). Recent studies of other neurodegenerative disorders such as dementia with LB (DLB), multiple system atrophy (MSA) and amyotrophic lateral sclerosis (ALS) also revealed intracellular accumulations of alpha-synuclein in affected brain regions. This may indicate that these disorders partially share common pathogenic mechanisms. Recent data provide first insights into the physiological function of alpha-synuclein and support the concept of an essential role of alpha-synuclein in neurodegeneration. Increasing knowledge on the pathogenic molecular mechanisms of neurodegeneration and of the pathophysiological function of alpha-synuclein in particular may influence future development of therapeutic strategies in neurodegenerative disorders.

Mutation analysis and association studies of the UCHL1 gene in German Parkinson's disease patients

Recently, an Ile93Met substitution has been identified in the ubiquitin carboxy-terminal hydrolase L1 (UCHL1) gene in a single German PD family with autosomal dominant inheritance. To determine whether mutations in the UCHL1 gene are causative for Parkinson's disease (PD) a detailed mutation analysis was performed in a large sample of German sporadic and familial PD patients. We found no disease-causing mutation in the coding region of the UCHL1 gene. Direct sequencing revealed six intronic polymorphisms in the UCHL1 gene. Analysis of an S18Y polymorphism in exon 3 of the UCHL1 gene in sporadic PD patients and controls showed carriers of allele 2 (tyrosine) significantly less frequent in patients with a reduced risk of 0.57 (CI = 0.36-0.88; p = 0.012, p(c) = 0.047, chi2 = 6.31). Our study shows that sequence variations in the coding region of UCHL1 are a rare event. A protective effect of a certain UCHL1 variant in the pathogenesis of sporadic PD is suggested, underlining the relevance of UCHL1 in neurodegeneration.

PCR/SSCP detects reliably and efficiently DNA sequence variations in large scale screening projects

A simple and fast method with high reliability is necessary for the identification of mutations, polymorphisms and sequence variants (MPSV) within many genes and many samples, e.g. for clarifying the genetic background of individuals with multifactorial diseases. Here we review our experience with the polymerase chain reaction/single-strand conformation polymorphism (PCR/SSCP) analysis to identify MPSV in a number of genes thought to be involved in the pathogenesis of multifactorial neurological disorders, including autoimmune diseases like multiple sclerosis (MS) and neurodegenerative disorders like Parkinson s disease (PD). The method is based on the property of the DNA that the electrophoretic mobility of single stranded nucleic acids depends not only on their size but also on their sequence. The target sequences were amplified, digested into fragments ranging from 50-240 base pairs (bp), heat-denatured and analysed on native polyacrylamide (PAA) gels of different composition. The analysis of a great number of different PCR products demonstrates that the detection rate of MPSV depends on the fragment lengths, the temperature during electrophoresis and the composition of the gel. In general, the detection of MPSV is neither influenced by their location within the DNA fragment nor by the type of substitution, i.e., transitions or transversions. The standard PCR/SSCP system described here provides high reliability and detection rates. It allows the efficient analysis of a large number of DNA samples and many different genes.

Dimers of pi protein bind the A+T-rich region of the R6K gamma origin near the leading-strand synthesis start sites: regulatory implications

The replication of gamma origin, a minimal replicon derived from plasmid R6K, is controlled by the Rep protein pi. At low intracellular concentrations, pi activates the gamma origin, while it inhibits replication at elevated concentrations. Additionally, pi acts as a transcription factor (auto)repressing its own synthesis. These varied regulatory functions depend on pi binding to reiterated DNA sequences bearing a TGAGNG motif. However, pi also binds to a "non-iteron" site (i.e., not TGAGNG) that resides in the A+T-rich region adjacent to the iterons. This positioning places the non-iteron site near the start sites for leading-strand synthesis that also occur in the A+T-rich region of gamma origin. We have hypothesized that origin activation (at low pi levels) would require the binding of pi monomers to iterons, while the binding of pi dimers to the non-iteron site (at high pi levels) would be required to inhibit priming. Although monomers as well as dimers can bind to an iteron, we demonstrate that only dimers bind to the non-iteron site. Two additional pieces of data support the hypothesis of negative replication control by pi binding to the non-iteron site. First, pi binds to the non-iteron site about eight times less well than it binds to a single iteron. Second, hyperactive variants of pi protein (called copy-up) either do not bind to the non-iteron site or bind to it less well than wild-type pi. We propose a replication control mechanism whereby pi would directly inhibit primer formation.

Genetic influence on the development of Parkinson's disease

In the last few years, the genetic contribution to Parkinson's disease has gained major attention and resulted in the identification of four gene loci in autosomal dominant and autosomal recessive Parkinson's disease. Several mutations in two genes have been shown to be responsible for neuronal cell death in Parkinson's disease. One of the gene products involved, alpha-synuclein, is a major component of Lewy bodies, the neuropathological feature of Parkinson's disease. In contrast, mutations in the parkin gene are associated with parkinsonism without Lewy body pathology. The elucidation of polygenic changes in the dopamine pathway, mitochondrial dysfunction, and of xenobiotic metabolism is technically now possible by means of association and genotype studies. The increasing knowledge of the pathogenesis of Parkinson's disease at a molecular level will have important implications for the development of individual therapeutic strategies to prevent disease progression.

Physiological features of primary cultures and subcultures of human retinal pigment epithelial cells before and after cryopreservation for cell transplantation

BACKGROUND

One striking disadvantage of in vitro culturing of human retinal pigment epithelial (RPE) cells is the loss of epithelial differentiation and specific cell function during culture. This may be one of the main reasons for the failure of RPE cell transplantation. The aim of this study was to evaluate cell culture conditions ensuring the maintenance of differentiation and function of RPE cells after subcultivation and storage in liquid nitrogen.

METHODS

Enzymatically isolated cells were seeded onto coated culture dishes, cultured with a specially formulated improved growth medium until confluence and then cryopreserved in liquid nitrogen for 16-66 months. HLA class I and II typing was performed before cryopreservation and after thawing. Expression of Ca2+ channels in primary, first-passage and cryopreserved RPE cells was studied using the patch-clamp technique.

RESULTS

After cryopreservation no loss of any HLA antigen was detectable in 12 of 14 cell strains studied. Patch-clamp experiments demonstrated that high-threshold L-type Ca2+ channels, which are typical for freshly isolated cells, could be detected in first-passage and cryopreserved RPE cells only when improved culture conditions were employed, not in conventionally cultured cells. The characteristics of these channels showed little change in subcultured cells compared to primary cultures.

CONCLUSION

This is the first study showing the maintenance of adult human RPE-specific cell differentiation and characteristics in vitro after primary culture and after cryopreservation using improved cell culture methods. The optimization and quality control of cell culture is an important prerequisite for successful cell transplantation.

[Structure of a cell bank for transplantation of HLA-typed, cryopreserved human adult retinal pigment epithelial cells]

BACKGROUND

The transplantation of retinal pigment epithelial cells (RPE) in patients with age-related macular degeneration is discussed as a future therapy. A cornea bank can serve as a source for cells that can be isolated, cultivated, HLA-typed and cryopreserved for subsequent tissue-compatible transplantation.

METHODS

RPE cells are isolated enzymatically from donor eyes and are cultured in a specially designed growth medium. After multiplication, one part of the culture is cryopreserved; the other part is subcultured for HLA-typing. Completely typed and morphologically sufficiently well-differentiated cell cultures are registered on a donor list (RPE cell bank) and can be provided for cell transplantations with matching HLA type in patients suffering from RPE degenerative diseases.

RESULTS

A total of 461 cell cultures have been prepared since 1996; 116 fully typed and well-differentiated cell cultures are stored in our cell bank. Since January 1998 patients who agreed to have an RPE transplantation have been registered on a waiting list. Seven transplantations have already been performed.

CONCLUSION

RPE cells can be stored cryopreserved in a cell bank and can be kept available for transplantation for a prolonged period of time.

Parkinson's disease--a multifactorial neurodegenerative disorder

The pathogenesis of idiopathic Parkinson's disease (PD) is not known, but is thought to be multifactorial, deriving from environmental factors acting on genetically predisposed individuals with aging. Association studies of DNA polymorphisms are able to detect a genetic background predisposing to PD. Mechanisms as oxidative stress, xenobiotica toxicity and altered dopamine metabolism might lead to a selective cell death of most vulnerable nerve cells and represent the primary subject to be studied by DNA analysis. Furthermore, protein aggregation is likely to be a major cause for the disease. Recently it has been shown that alpha-synuclein is accumulated in Lewy bodies of sporadic PD and mutated in some rare families with an autosomal dominant trait of the disease (ADPD). The identification of further genes responsible for PD will subsequently lead to first insights into the pathogenesis of one of the most common neurodegenerative disorders in humans.

Analysis of the parkin deletion in sporadic and familial Parkinson's disease. Short communication

Recently a mutation in the parking gene has been identified as the cause for an autosomal-recessively inherited form of early onset Parkinson's disease (EOPD). The disease causing minimal deletion has been defined as a homozygous exon 4 loss in the parkin gene among Japanese patients. We investigated 140 sporadic and familial EOPD patients of German ancestry for the exon 4 deletion in the parkin gene. None of our patients exhibited a homozygous deletion of exon 4, suggesting a minor role of this mutation for EOPD in Caucasians. Nevertheless a detailed mutation analysis is warranted to explore the overall significance of mutations in the parkin gene in EOPD.

Increased susceptibility to sporadic Parkinson's disease by a certain combined alpha-synuclein/apolipoprotein E genotype

Parkinson's disease (PD) is one of the most common neurodegenerative disorders affecting about 1% of Western populations older than age 50. The pathological hallmark of PD are Lewy bodies, that is, intracytoplasmic inclusion bodies in affected neurons of the substantia nigra. Recently, alpha-synuclein (alpha-SYN) has been identified as the main component of Lewy bodies in sporadic PD, suggesting involvement in neurodegeneration via protein accumulation. The partially overlapping pathology of PD and Alzheimer's disease, as well as striking structural similarities of alpha-SYN and apolipoprotein E, which is a major risk factor for late-onset Alzheimer's disease, prompted us to investigate the influence of different alpha-SYN and apolipoprotein E alleles for developing sporadic PD. We performed association studies in 193 German PD patients and 200 healthy control subjects matched for age, sex, and origin. A polymorphism in the promoter region of the alpha-SYN gene (NACP-Rep1) as well as of the closely linked DNA markers D4S1647 and D4S1628 revealed significant differences in the allelic distributions between PD patients and the control group. Furthermore, the Apo epsilon4 allele but not the Th1/E47 promoter polymorphism of the apolipoprotein E gene was significantly more frequent among early-onset PD patients (age at onset, <50 years) than in late-onset PD. Regarding the combination of the Apo epsilon4 allele and allele 1 of the alpha-SYN promoter polymorphism, a highly significant difference between the group of PD patients and control individuals has been found, suggesting interactions or combined actions of these proteins in the pathogenesis of sporadic PD. PD patients harboring this genotype have a 12.8-fold increased relative risk for developing PD during their lives.

Predictors of bone mineral density in patients with eating disorders

OBJECTIVE

The objective of this study was to examine potential clinical predictors of bone density in patients with eating disorders.

METHOD

We studied 137 women with anorexia nervosa, bulimia nervosa, or eating disorder not otherwise specified (NOS) after admission to the hospital. Clinical data of patients were collected by clinical interview and standardized questionnaires. Bone mineral density of the lumbar spine was measured by dual energy x-ray absorptiometry.

RESULTS

Lumbar bone density was significantly correlated to present and past minimum weight even after correction for height and age. Other factors did not reach significance.

CONCLUSION

Normalized present and past weight is the best predictor of lumbar bone density in patients with eating disorders. Factors like reduced caloric intake, binge eating, vomiting, menstrual status, and use of estrogen, laxatives, and nicotine seem to have no independent effect on bone density in this group of patients.