Biomedical subjects

U Finckh

Publications and source records attributed to U Finckh.

35 records · Page 2Linked to original sources

PubMed1998

Genetic association of an alpha2-macroglobulin (Val1000lle) polymorphism and Alzheimer's disease.

alpha2-Macroglobulin (A2M) is a proteinase inhibitor found in association with senile plaques (SP) in Alzheimer's disease (AD). A2M has been implicated biochemically in binding and degradation of the amyloid beta (Abeta) protein which accumulates in SP. We studied the relationship between Alzheimer's disease and a common A2M polymorphism, Val1000 (GTC)/Ile1000 (ATC), which occurs near the thiolester active site of the molecule. In an initial exploratory data set (90 controls and 171 Alzheimer's disease) we noted an increased frequency of the G/G genotype from 0.07 to 0.12. We therefore tested the hypothesis that the G/G genotype is over-represented in Alzheimer's disease in an additional independent data set: a group of 359 controls and 566 Alzheimer's disease patients. In the hypothesis testing cohort, the G/G genotype increased from 0.07 in controls to 0.12 in Alzheimer's disease (P < 0.05, Fisher's exact test). The odds ratio for Alzheimer's disease associated with the G/G genotype was 1.77 (1.16-2.70, P < 0.01) and in combination with APOE4 was 9.68 (95% CI 3.91-24.0, P < 0.001). The presence of the G allele was associated with an increase in Abeta burden in a small series. The A2M receptor, A2M-r/LRP, is a multifunctional receptor whose ligands include apolipoprotein E and the amyloid precursor protein. These four proteins have each been genetically linked to Alzheimer's disease, suggesting that they may participate in a common disease pathway.

Alleles↗

PubMed1998

Simple PCR amplification of the entire glucocerebrosidase gene (GBA) coding region for diagnostic sequence analysis.

Mutations in the human glucocerebrosidase gene (GBA) may lead to Gaucher disease-an autosomal recessive, lysosomal storage disease. In about 15-25% of Caucasian patients with Gaucher disease yet the disease-causing mutations remain to be identified. There exists 16kb downstream from the functional GBA gene (chromosome 1q21) a highly homologous transcribed pseudogene (GBAP) with some sequence differences to GBA. These sequence differences might erroneously imitate a true mutation in the functional gene if an unintentional co-investigation of the pseudogene occurred. We describe a protocol which allows the selective analysis of a PCR-amplified 7.1 kb genomic GBA-fragment encompassing the entire GBA coding region. Direct, nonradioactive double stranded cycle-sequencing procedure of nested PCR fragments from this long range GBA-specific product allowed the sequencing of the coding exons including the flanking splice sites. Several, so far unknown coding mutation were identified in non-Jewish families with Gaucher disease. This protocol allows the rapid detection of new GBA mutations.

Chromosomes, Human, Pair 1↗

PubMed1997

Allelic association of a dopamine transporter gene polymorphism in alcohol dependence with withdrawal seizures or delirium.

Hereditary factors confer susceptibility to alcohol dependence. Alcohol mediates its reinforcing effects by enhancing dopamine activity in the mesolimbic dopamine system. The role of the dopamine transporter in terminating dopaminergic activity in synaptic neurotransmission suggests that variants of the dopamine transporter gene (DAT1) might contribute to individual differences in vulnerability to addictive behavior. Our population-based association study investigated whether variants of DAT1 confer susceptibility to alcohol dependence in 293 alcoholics and clinically more homogeneous subgroups formed by: positive family history, early age-at-onset, delirium, withdrawal seizures, antisocial tendencies, type 1 and 2 alcoholics. Analyzing a VNTR polymorphism in the 3' untranslated region of DAT1, we found a significantly increased prevalence of the nine-repeat allele in 93 alcoholics displaying withdrawal seizures or delirium, compared with 93 ethnically matched nonalcoholic controls (p = 0.003; OR = 2.44; 95% confidence interval: 1.35-4.43). Our data provide evidence that a major genetic determinant of DAT1 influences vulnerability to severe alcohol withdrawal symptoms.

Adult↗

PubMed1997

Mutations in RPE65 cause autosomal recessive childhood-onset severe retinal dystrophy.

Autosomal recessive childhood-onset severe retinal dystrophy (arCSRD) designates a heterogeneous group of disorders affecting rod and cone photoreceptors simultaneously. The most severe cases are termed Leber congenital amaurosis (LCA), while the less aggressive forms are usually considered juvenile retinitis pigmentosa. Recently, mutations in the retinal-specific guanylate cyclase gene were found in patients with LCA. Disease genes implicated in other forms of arCSRD are expected to encode proteins present in the neuroretina or in the retinal pigment epithelium (RPE). The RPE, a monolayer of cells separating the vascular-rich choroid and the neuroretina, is in intimate contact with the outer segments of rods and cones via the microvilli surrounding the photoreceptors. The RPE expresses a tissue-specific and evolutionarily highly conserved 61 kD protein (RPE65) present at high levels in vivo. Although the function of RPE65 is not yet known, an important role in the RPE/photoreceptor vitamin-A cycle is suggested by the fact that RPE65 associates both with serum retinol-binding protein and with the RPE-specific 11-cis retinol dehydrogenase, an enzyme active in the synthesis of the visual pigment chromophore 11-cis retinal. Here we report that the analysis of RPE65 in a collection of about 100 unselected retinal-dystrophy patients of different ethnic origin revealed five that are likely to be pathogenic mutations, including a missense mutation (Pro363Thr), two point mutations affecting splicing (912 + 1G-->T and 65 + 5G-->A) and two small re-arrangements (ins144T and 831del8) on a total of nine alleles of five patients with arCSRD. In contrast to other genes whose defects have been implicated in degenerative retinopathies, RPE65 is the first disease gene in this group of inherited disorders that is expressed exclusively in the RPE, and may play a role in vitamin-A metabolism of the retina.

Age of Onset↗

PubMed1997

Isolation of canine retinal arrestin cDNA and exclusion of three candidate genes for Swedish Briard retinal dystrophy.

PURPOSE: Mutations of genes encoding various retina-specific proteins are known to cause a wide spectrum of inherited retinal dystrophies in different species. In the canine, several types of genetic retinal dystrophies have been described affecting primarily the photoreceptors and/or the retinal pigment epithelium. We are performing a systematic analysis of canine candidate genes for such diseases to identify the one mutated in the retinal dystrophy in Swedish Briard dogs. METHODS: We isolated and characterised the full length cDNA of canine retinal arrestin by the method of rapid amplification of cDNA ends (RACE). RESULTS: The full length cDNA isolated by us is 1,575 base pairs (bp) long and contains a 1,218 bp-long open reading frame. CONCLUSIONS: The homology of the canine arrestin protein is highest with the human analogue (88.9%) and lowest with mouse arrestin (85.3%). The most obvious sequence differences among the different arrestins are in the extreme carboxyl terminus. PCR-SSCP (single strand conformation polymorphism) analysis and direct sequencing of retinal cDNA didn't provide any evidence that mutations in the canine arrestin gene are responsible for the retinal dystrophy seen in the Swedish strain of Briard dogs. Similar data were obtained for the genes encoding rhodopsin and the beta-subunit of photoreceptor-specific phosphodiesterase by segregation analysis.

Amino Acid Sequence↗

PubMed1997

Influence of the dopamine D2 receptor (DRD2) genotype on neuroadaptive effects of alcohol and the clinical outcome of alcoholism.

The present study was performed to test the hypotheses that allelic variants at the human dopamine D2 receptor gene locus (DRD2) confer susceptibility to alcoholism or are associated with clinical subtypes of alcoholism. We investigated an A --> G substitution polymorphism in the 3'-untranslated region of exon 8 (E8) of DRD2 with allele frequencies of f(G) = 0.295 - 0.329. No significant association of the DRD2 genotype or allele frequencies with alcoholism was found in an association study including 283 alcoholics and 146 non-alcoholic controls. However, the frequent homozygous E8 A/A genotype with f(AA) = 0.47 - 0.48 was associated with increased anxiety and depression scores in alcoholics during the follow up after clinical detoxification treatment. In addition, E8 A/A was associated with increased suicide attempts and showed a tendency towards more severe withdrawal symptoms, early relapse and reduced responsiveness to the dopaminergic agonist apomorphine. Regression analysis revealed the DRD2 E8 genotype as the only significant factor determining withdrawal severity in female alcoholics. The findings suggest an influence of the DRD2 genotype on the neuropharmacological effects of chronic alcohol exposure and the clinical course of alcoholism.

Adaptation, Physiological↗

PubMed1997

Absence of angiotensin II type 1 receptor gene mutations in human adrenal tumors.

Regulatory actions of angiotensin II (AngII), which is involved in the pathophysiology of hypertension and also participates in cell proliferation and cell differentiation, are mainly mediated by AngII type 1 (AT1) receptor. Recently, activating mutations of receptors causing hyperfunctioning endocrine diseases have been described in the case of the TSH and LH receptors, implicating that such mutations might occur in other G-protein-coupled receptors. Furthermore it seems to be possible that genetic variations of AT1 receptor have an influence upon the action of AngII. Therefore, we searched by sequence analysis of the coding region of AT1 receptor gene for activating mutations and genetic polymorphisms in 56 human adrenal tumors (16 aldosterone-producing adenomas, 10 cortisol-producing adenomas, 1 aldosterone-producing carcinoma, and 29 incidentalomas). We were not able to identify any activating mutation in the coding region of AT1 receptor gene. We conclude that activating mutations of the AT1 receptor are not a major cause of the development of adrenal adenomas, if at all. In addition, polymorphic subtypes of AT1 receptor do not seem to play a major role in the pathogenesis of these tumors, even though a tendency towards a higher frequency of the polymorphic base substitution at position 573 (T573-->C) in cortisol-producing tumors needs to be further evaluated.

Adenoma↗

PubMed1996

Dopamine D2 receptor gene (DRD2) haplotypes in Caucasians.

The human dopamine D2 receptor gene (DRD2) is considered a candidate gene for neuro-psychiatric diseases. We typed three new DNA sequence variants in DRD2 intron 4, intron 6 and exon 8, in combination with the known TaqI A restriction fragment length polymorphism (RFLP) and exon 7 311Ser/Cys in 106 unrelated psychiatrically healthy Caucasians. Based on the genotypic data we delineated 10 distinct DRD2 haplotypes and their genetic relationship. Our data provide evidence that the Taq A1 allele and the 311Cys variant are components of different groups of haplotypes though both variants have been speculated to be associated with alcoholism or schizophrenia in recent studies. Therefore we conclude that the prior knowledge of the frequencies and genetic relationships of DRD2 haplotypes will lead to the selection of more suitable intragenic markers for future association studies.

Gene Frequency↗

PubMed1996

No association of the structural dopamine D2 receptor (DRD2) variant 311Cys with alcoholism.

The human dopamine D2 receptor (DRD2) has been implied in the vulnerability for alcoholism and/or the modification of its severity. This is supported through animal experimental and pharmacological data. We analyzed the DRD2 311Ser/Cys polymorphism in 312 German alcoholics and 131 ethnically matched controls to investigate the association of genetic DRD2 variants with alcoholism or clinical characteristics of homogeneous subgroups of alcoholics. We observed no association between the 311Cys variant and alcoholism, and none of the clinical characteristics evaluated was significantly associated with 311Cys. The allele frequencies of the 311Cys variant were 0.026 and 0.031 in the alcoholics and controls, respectively. These are the highest reported 311Cys frequencies in Caucasians. The DRD2 TaqI A1/A2 restriction fragment length polymorphism was analyzed simultaneously in our samples. In most cases, the 311Cys allele is associated with the TaqI A2-allele. Data do not suggest a clinical relevance of the 311Cys variant in alcoholism. However, the relevance of this variant in other diseases or the existence of other DRD2 variants with altered receptor function or expression cannot be excluded.

Adult↗

PubMed1996

Lack of allelic association of dopamine D1 and D2 (TaqIA) receptor gene polymorphisms with reduced dopaminergic sensitivity to alcoholism.

Our study tested the hypothesis of whether the sensitivity of central dopamine receptors corresponds to the genotypic constitution of DNA-polymorphisms of the dopamine D1 and D2 receptor (DRD1, DRD2) genes and is associated with poor treatment outcome. Therefore, 97 alcohol-dependent patients were assessed according to their sensitivity of central dopamine receptors (apomorphine-induced secretion of growth hormone), clinical outcome during a 6-month observation period, and genotypic constitution of the TaqIA restriction fragment length polymorphism (RFLP) at the DRD2 locus and of the Bsp1286I RFLP at the DRD1 locus. On the 1st day of detoxification, dopamine receptor hyposensitivity was found in treatment nonresponders, but not in responders. Apomorphine-induced growth hormone release did not differ significantly in alcoholics with different genotypes of the DRD1 and DRD2 RFLPs. Neither did we find a significant allelic association with treatment response. Thus, we did not find evidence for a genetic determination of dopamine receptor hyposensitivity in alcoholics with poor treatment outcome.

Adult↗

PubMed1996

Two new missense mutations in a non-Jewish Caucasian family with type 3 Gaucher disease.

Gaucher disease is an autosomal recessive, lysosomal storage disease caused by a deficiency of the enzyme glucocerebrosidase. The prevalence of this disorder differs significantly among various populations and is highest in some Jewish populations. More than 35 disease-producing mutations of the gene have been reported. The change of the amino acid leucine at position 444 to proline (444Leu-->Pro) is the most common mutation in non-Jewish populations, and a second mutation at amino acid 370 (370Asn-->Ser) is the most common one in Jewish populations. However, most of the mutations have been reported in very few cases or even in only one pedigree. We performed a direct DNA sequencing analysis of the complete functional glucocerebrosidase gene in a 22-year-old neuronopathic non-Jewish patient with Gaucher disease type 3 with myoclonic epilepsy and slight mental disturbances and in most members of his family. After selective amplification of the complete coding region of the patient's functional glucocerebrosidase gene, we identified two hitherto unreported mutations in exon 9 (genomic nucleotide 5224G-->C; 417Val-->Leu) and in exon 11 (genomic nucleotide 6668C-->T; 510Thr-->Ile). Each parent showed one of these mutations. Once we sequenced the complete active gene, we could rule out the existence of further mutations. Data that show that in about 15 to 25% of non-Jewish patients with Gaucher disease no mutations within the glucocerebrosidase gene are found may be due to inappropriate screening methods, mostly used for the genotyping. Until we have precise information about the frequency and distribution of single-point mutations in patients with Gaucher disease, it is necessary to analyze the complete glucocerebrosidase gene.

Adult↗

PubMed1996

Allele-specific PCR for simultaneous amplification of both alleles of a deletion polymorphism in intron 6 of the human dopamine 2 receptor gene (DRD2).

The human dopamine 2 receptor gene (DRD2) is an important candidate gene for drug addiction and alcoholism. So far, no mutations within the coding region of DRD2 have been found to be associated with addiction disorders. To identify sequence polymorphisms for further haplotype analyses and to analyze the importance of possible intron sequence variations of the human DRD2 gene (>260kb) in greater cohorts and in a routine manner we established an optimized methodological procedure for polymerase chain reaction (PCR) amplification and direct non-radioactive sequencing followed by a bidirectional allele-specific PCR protocol; the latter one allows the simultaneous amplification of several alleles in one reaction tube. Overall, the sequences of the DRD2 introns 3-7 are highly conserved. Nevertheless, in each of the analyzed intron sequences we found substitution variants as well as a one base-pair deletion polymorphism in intron 6. The allele-specific PCR allowed the reliable testing of 95 healthy control individuals and 270 alcoholics for analyzing a possible genetic association of this newly characterized polymorphic DRD2 marker with alcoholism in an ethnically and clinically homogenous group of patients. However, the observed allele frequencies for the 1bp deletion polymorphism were 15.9% for the alcoholics and 15.3% for the controls suggesting no association of the deletion to alcoholism.

Alleles↗

PubMed1996

Absence of human T-lymphotrophic virus type I in patients with systemic lupus erythematosus.

The role of the human T-cell lymphotropic/leukaemia virus type I (HTLV-I) in the pathogenesis of autoimmune diseases of unknown cause, such as systemic lupus erythematosus (SLE), multiple sclerosis (MS) or Sjögren's syndrome (SS) has been discussed extensively. We have investigated whether SLE is in any way associated with exogenous HTLV-I. Using enzyme immunoassay (EIA), we found no seroreactivity against HTLV-I antigens in any of 24 SLE patients under investigation. Using a radioimmunoprecipitation assay (RIPA), there was also no expression of retroviral tax-protein demonstrable in 24 individuals with SLE. DNA preparations of peripheral blood cells, as well as isolated CD4- and CD8-positive cells, were examined for HTLV-I sequences (pol-, env-, gag-, LTR- and tax-region) using polymerase chain reaction (PCR). We were unable to demonstrate any specific HTLV-I PCR products in SLE specimens. Our data suggest that exogenous HTLV-I is not involved in the pathogenesis of SLE. Systemic lupus erythematosus (SLE) is a multisystem disease of unknown cause characterized by B-cell hyperactivity with hypergammaglobulinaemia and the formation of pathogenic autoantibodies. Patients may also show altered suppressor/helper T-cell ratios. Abnormalities in T-cell function include T-cell lymphopenia, expression of activation antigens and alteration of responses to mitogens and lymphokines. Human retroviruses are known to cause immune aberrations, such as diminished T-cell function and polyclonal B-cell stimulation, which are observed in patients with leukaemias, lymphomas and the acquired immunodeficiency syndrome (AIDS). Human T-cell lymphotropic/leukaemia (HTLV-I) is aetiologically linked with adult virus type I T-cell leukaemia (ATL) and tropical spastic paraparesis. A common feature of the HTLV family is an LTR encoded protein (tax protein, p40tax) which triggers viral protein production in the early stages of a retroviral infection. Detection of p40tax may indicate transcriptional activity of a provirus. Several investigators have examined the possible involvement of HTLV-I in SLE and have produced conflicting results, especially so far as seroreactivity against HTLV-I antigens is concerned. The discovery of HTLV-I like particles in murine lupus might also indicate an important role of exogenous viruses in SLE. Olsen and colleagues describe a high seropositivity to anti-HTLV-I- and anti-HTLV-III antibodies and evidence of viral replication in patients with SLE. Lin et al. also demonstrated anti-HTLV-I antibodies in SLE patients. However, other authors failed to detect anti-HTLV-I antibodies, proviral structures or viral transcripts in SLE. We investigated whether or not there are any indications of the presence of the exogenous retrovirus, HTLV-I, in patients with SLE, at immunological and genetic levels. We found neither immunological nor molecular biological evidence for the existence of HTLV-I in SLE patients. There were some weak suggestions of the presence of possibly endogenous retroviral sequences.

Antibodies, Viral↗

PubMed1995

Dopamine D1, D2 and D3 receptor genes in alcohol dependence.

Hereditary factors play a substantial role in the etiology of alcohol dependence. Alcohol mediates its reinforcing effects by an activation of the mesolimbic dopamine system. These findings suggest that the genes encoding the dopamine receptor (DR) subtypes represent high-ranking candidates for susceptibility genes to addictive disorders. Our present population-based association study investigated whether sequence variants of the dopamine D1, D2 and D3 receptor genes confer susceptibility to alcohol dependence in 278 alcoholics, and clinically more homogeneous subgroups ascertained through positive family history, early age at onset, delirium, withdrawal seizures and antisocial tendencies. No evidence for an allelic association was found for the PCR-based TaqA RFLP fo the DRD2 gene and a Bsp1286I RFLP of the DRD1 gene. Without correction for multiple testing, we found a significantly increased allele frequency of a common DRD3 gene variant expressing a serine at position 9 in the extracellular N-terminal part of the receptor protein in 55 alcohol-dependent individuals with delirium (chi 2 = 4.1, df = 1, p = 0.042). Further studies have to examine whether this amino acid substitution or a nearby mutation confers genetic susceptibility to at least a subgroup of alcohol-dependent individuals with delirium.

Adult↗

PubMed1995

Clinical evaluation of a Mycobacterium tuberculosis PCR assay.

On the basis of previously published PCR primer sequences, we have designed a sensitive system for detecting DNA of the Mycobacterium tuberculosis complex (MTB) in patient sputum samples which employs a fast and simplified sample preparation method appropriate for routine diagnostic testing. In order to evaluate the accuracy of the PCR assay, we performed a prospective study with 103 patients, comparing PCR results with culture results of samples obtained from a parallel culture assay as well as with subsequent culture results. Using two MTB-specific PCR primer systems, we found 48 of 49 tuberculosis (Tb) patients to be PCR positive (PCR sensitivity, 0.98). Sixteen of 54 presumably non-Tb patients showed amplifiable MTB DNA (specificity, 0.7). The study demonstrates that for diagnostic applications of MTB PCR two MTB-specific primer pairs should be used. MTB infection is extremely unlikely in cases of MTB PCR-negative samples: with our method for the exclusion of active Tb, the validity of one PCR assay seems to be equivalent to those of at least three culturing procedures. Positive PCR results do not necessarily reflect active MTB infection. It remains to be shown whether positive PCR results in Tb-negative patients mean false-positivity, an early laboratory finding which predicts a subsequent reactivation of a prior Tb infection, or whether asymptomatic patients may carry PCR-amplifiable MTB DNA without any clinical relevance. It is important to point out that the validity of PCR results in clinical studies depends on the use of contamination controls parallel to all PCR steps and the simplicity of the DNA extraction method as well as on the specificity of the PCR results.

Base Sequence↗

PubMed1995

Amplification of Mycobacterium tuberculosis from peripheral blood.

To determine the value of the PCR assay of lymphomonocytic blood cells for the diagnosis of pulmonary tuberculosis, we compared, in a prospective study, PCR results with results of conventional diagnostic methods of Mycobacterium tuberculosis detection. Clinical investigators who were unaware of the PCR data classified 162 immunocompetent patients, who had been hospitalized because of suspected pulmonary tuberculosis, in accordance with the recommendations of the American Thoracic Society (ATS). By testing blood samples from these patients for mycobacterial DNA with three different PCR systems, we were able to demonstrate that nonquantitative PCR of peripheral blood leukocytes is of little value for the specific diagnosis of pulmonary tuberculosis. However, semiquantitative PCR assays might have some significance since we found an increasing level of mycobacterial DNA copies in blood from patients classified in ATS groups 2 to 5.

Base Sequence↗

PubMed1991

Producing single-stranded DNA probes with the Taq DNA polymerase: a high yield protocol.

We report an efficient procedure to synthesize either single- or double-stranded probes labeled with biotin-11-dUTP, biotin-21-dUTP or digoxigenin-11-dUTP. To produce the single-stranded probe, only a single primer is utilized in a Taq polymerase amplification of 55 cycles. A cytomegalovirus probe is presented. This procedure allows easy production of nonradioactively labeled pure single-stranded probes of any desired length and specificity.

Base Sequence↗