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Biomedical subjects

C Zander

Publications and source records attributed to C Zander.

28 records · Page 2Linked to original sources
PubMed1996

An expanded CAG repeat sequence in spinocerebellar ataxia type 7.

Expanded CAG repeat sequences have been identified in the coding region of genes mutated in several neurodegenerative disorders, including spinocerebellar ataxia type 1 and Machado-Joseph disease. In all disorders described to date the CAG expansion codes for an elongated polyglutamine chain. An increased polyglutamine chain size leads to a more severe disease, thus correlating with the genetic anticipation seen in repeat expansion disorders. Spinocerebellar ataxia type 7 (SCA7) is an autosomal dominant spinocerebellar ataxia with anticipation and a progressive degeneration of the cerebellar cortex. Using repeat expansion detection (RED), a method in which a thermostable ligase is used to detect repeat expansions directly from genomic DNA, we have analyzed 8 SCA7 families for the presence of CAG repeat expansions. RED products of 150-240 bp were found in all affected individuals and found to cosegregate with the disease (P < 0.000001, n = 66), indicating strongly that a CAG expansion is the cause of SCA7. On the basis of a previously established correlation between RED product sizes and actual repeat sizes in Machado-Joseph disease, we were able to estimate the average expansion size in SCA7 to be 64 CAG copies.

Chromosome Mapping↗
PubMed1996

Mutation detection in Machado-Joseph disease using repeat expansion detection.

BACKGROUND: Several neurological disorders have recently been explained through the discovery of expanded DNA repeat sequences. Among these is Machado-Joseph disease, one of the most common spinocerebellar ataxias (MJD/SCA3), caused by a CAG repeat expansion on chromosome 14. A useful way of detecting repeat sequence mutations is offered by the repeat expansion detection method (RED), in which a thermostable ligase is used to detect repeat expansions directly from genomic DNA. We have used RED to detect CAG expansions in families with either MJD/SCA3 or with previously uncharacterized spinocerebellar ataxia (SCA). MATERIALS AND METHODS: Five MJD/SCA3 families and one SCA family where linkage to SCA1-5 had been excluded were analyzed by RED and polymerase chain reaction (PCR). RESULTS: An expansion represented by RED products of 180-270 bp segregated with MJD/SCA3 (p < 0.00001) in five families (n = 60) and PCR products corresponding to 66-80 repeat copies were observed in all affected individuals. We also detected a 210-bp RED product segregating with disease (p < 0.01) in a non-SCA1-5 family (n = 16), suggesting involvement of a CAG expansion in the pathophysiology. PCR analysis subsequently revealed an elongated MJD/SCA3 allele in all affected family members. CONCLUSIONS: RED products detected in Machado-Joseph disease families correlated with elongated PCR products at the MJD/SCA3 locus. We demonstrate the added usefulness of RED in detecting repeat expansions in disorders where linkage is complicated by phenotyping problems in gradually developing adult-onset disorders, as in the non-SCA1-5 family examined. The RED method is informative without any knowledge of flanking sequences. This is particularly useful when studying diseases where the mutated gene is unknown. We conclude that RED is a reliable method for analyzing expanded repeat sequences in the genome.

Alleles↗
PubMed1995

Detection of expanded CAG repeats in bipolar affective disorder using the repeat expansion detection (RED) method.

Genetic factors are of major aetiological importance in Bipolar Affective Disorder (BPAD type I and II). The exact mode of inheritance of BPAD is unknown, but the recent demonstration of anticipation suggests that dynamic mutations could be involved in the clinical expression of the disease. We have used the repeat expansion detection (RED) method to test whether the anticipation in BPAD could be explained by the presence of expanded trinucleotide repeat sequences. Using a (CTG)10 oligonucleotide a significantly higher number of expanded CAG repeats were found in the genomic DNA of two independent samples of unrelated BPAD patients of Swedish and Belgian ancestry as compared with normal controls. The difference in repeat number was more consistent if data of the two samples of patients was pooled. In this study a CAG trinucleotide repeat expansion was associated for the first time with a major psychiatric disorder. It is possible that the CAG trinucleotide repeat expansion is involved in the clinical expression of BPAD and that it is the molecular basis explaining the phenomenon of anticipation observed in this disorder.

Aged↗
PubMed1995

Multicenter German reference data base for peripheral quantitative computer tomography.

The wide spread use of bone densitometers in Germany and other European countries has required the establishment of a validated reference population data base. A semianthropomorphic forearm cross-calibration phantom (EFP), developed during a concerted research action of the European Union's programme in Biomedical Engineering (COMAC-BME), was used to cross-calibrate the peripheral quantitative computer tomography (pQCT) devices at four German centers participating in the multicenter study. In total, 723 women and 208 men were included in the normal data base. No significant regional differences were found between the data of the different centers. In addition to the manufacturers calibration standard, proper calibration of the pQCT devices could be monitored during collection of the normal female and male data base. As a merit of the COMAC-BME study the measurements obtained with all pQCT devices thus ensured an uniform reference data base for distal radius measurements in Germany.

Adult↗
PubMed1987

[Roentgen diagnosis following knee surgery].

After ventralization of the tibial tuberosity (Bandi-operation) the elevation can be shown. Chip and cortical fractures radiologically are demonstrated. After medialization of the patella ligament (Roux-Hauser operation) the site of excision is seen as a hyperlucent area and the site of apposition as a hyperdense area. After implantation of a sledge prosthesis risk factors indicating future complications can be identified by early postoperative radiography.

Aged↗
PubMed1986

[The cartilage in nuclear magnetic resonance tomography].

Comparison of MRI tomograms with anatomic sections shows that the limits of the joint cartilage do not correspond to the hitherto assumed zone of the more intensive signal. This intensive signal may be caused merely by the surface of the cartilage. Considering its extent, the signal-free zone bordering on this zone should also be cartilage. Since, e.g., in the knee, there is no subchondral substantia corticalis and, as is clearly recognizable in the anatomic section, bone marrow extends as far as the cartilage, this signal-poor zone should also correspond, at least in part, to cartilage. It is conceivable that the boundary areas in the MRI tomogram (in this case the cartilage surface) are demonstrated and that the signal behavior of the hyaline joint cartilage is not uniform and applicable to all sections. This also applies to fibrous cartilage.

Atlanto-Occipital Joint↗
PubMedDate not supplied

Single-molecular detection in solution: a new tool for analytical chemistry.

Single-molecule detection (SMD) is becoming more and more popular in the scientific community and is on the threshold to become a technique for laboratory use. Therefore, conceivable applications as well as optimized conditions for SMD will be discussed. To point out the possibilities of SMD, the signal-to-background ratio and the detection efficiency, in combination with the probability of misclassification, will be contemplated.

Chemistry Techniques, Analytical↗