Search PubMed⌕ Search

Biomedical subjects

B Brinkmann

Publications and source records attributed to B Brinkmann.

At least 181 records · Page 10Linked to original sources

Evaluation of an ACTBP2 ladder composed of 26 sequenced alleles.

A total of 90 alleles found in white Caucasians from North-West Germany were sequenced and 26 alleles chosen to construct a uniform and reliable allelic ladder for the STR system ACTBP2 (SE33). In addition 3 new aspects concerning the sequence structure were observed. Population studies were carried out on white Caucasians (n = 278) from North-West Germany using the new improved ladder. A total of 24 alleles and 14 "interalleles" were found and reproducible results obtained. No significant deviation from Hardy-Weinberg-equilibrium could be observed.

Alleles↗

Observation of null alleles apparently due to deletions.

After examining 2 paternity cases in 17 classical, 4 RFLP and 5 PCR-VNTR systems, isolated pseudo-exclusions were observed in the polymorphism D2S44 (YNH24). In both cases the "exclusions" were due to apparent opposite homozygosity. The application of different restriction enzymes, PCR amplification and varying electrophoretic conditions each led to an equivalent result of a 1-band-pattern with a mismatch between both father/child pairs. From these results the authors conclude that a complete or almost complete loss of the alleles is the most probable explanation.

Alleles↗

HumFES/FPS and HumF13B: Turkish and German population data.

The allele distribution of two STRs has been investigated in two populations, i.e. Turks (n = 203/200) and Germans (n = 414/402). The Turkish population showed 11 alleles in HumFES/FPS and 6 alleles in HumF13B while the German population had 9 (FES) and 8 (F13B) alleles respectively. Although the frequency profiles looked quite similar in both populations, there exist significant differences mainly due to alleles 8 and 10 (F13B) and allele 12 (FES). Four variant alleles have been sequenced and are described. Investigation of 368 (FES)/372 (F13B) meioses revealed no new mutations.

DNA↗

Frequency profiles of 3 STRs in a Turkish population.

Population genetic studies were carried out on Caucasians from southern Turkey (n = 204 individuals) using the short tandem repeat (STR) systems HumTHO1, HumVWA and HumACTBP2. After electrophoresis in polyacrylamide gels, 6 alleles could be identified for HumTHOI, 7 alleles for VWA and 26 alleles for ACTBP2. No significant deviations from Hardy-Weinberg equilibrium could be observed.

Belgium↗

Structure of new mutations in 2 STR systems.

Isolated father/child mismatches in cases with a high probability of paternity (W > 99.9%) have been investigated using short tandem repeat (STR) systems. According to the high probability of paternity new mutations could be assumed in these cases. A new mutation could be observed in 3 cases using the STR system HumACTBP2. Two of these cases showed a deletion and 1 case an insertion of 1 repeat (AAAG-motif) which could be verified by sequencing. In another paternity case a new mutation--1-repeat insertion (TCTA-motif)--in the HumVWA system was detected and verified by sequencing. These findings led to a new mutation rate of 0.7% (n = 453 meioses) for HumACTBP2 and 0.2% for HumVWA (n = 484 meioses).

Adult↗

Population genetic study from the Zagreb area using 3 STR systems.

Population genetic studies were carried out on Caucasians from north-west Croatia (Zagreb-area) using the short tandem repeat (STR) systems HumTHO1, HumVWA and HumACTBP2. After electrophoresis in PAG, 6 alleles could be identified for HumTHO1 in a sample size of 100 unrelated individuals and 7 alleles were found for VWA. For ACTBP2, 25 alleles have been identified. No significant deviations from Hardy-Weinberg equilibrium could be observed.

Alleles↗

D1S80 (pMCT118): analysis of 3 ethnic subpopulations living in Brussels.

Population genetic studies were carried out on 3 ethnic subpopulations living in Brussels (119 Belgians, 120 Turks and 137 Moroccans). DNA extraction was performed using the Chelex method. After DNA amplification the DNA fragments were separated electrophoretically in horizontal polyacrylamide gels. A total of 32 alleles (between 21 and 25 alleles in each subpopulation) including 8 "interalleles" could be differentiated. The allele frequencies were compared with population data from a German study and no significant differences could be observed.

Alleles↗

PCR-VNTRs (PCR-Variable Number of Tandem Repeats) in forensic science.

PCR-VNTRs are important markers for the individualization in forensic science. Before their use in routine case work extensive validation studies such as population genetics, mutation rates and experimental sensitivity studies have to be carried out. Different applications of PCR-VNTRs in stain analysis, even with difficult stain material such as hair shafts and only a few sperm cells are demonstrated. The different extent of sequence heterogeneity in STR systems was verified by Taq-cycle-sequencing. STRs can be divided into systems with a constant (HumTH01), variable (HumVWA) and highly variable (HumACTBP2) sequence structure. As a consequence some STR systems are not only characterized by their length polymorphism, but also by a highly variable sequence polymorphism.

Alleles↗

Allelic ladder characterization of the short tandem repeat polymorphism located in the 5' flanking region to the human coagulation factor XIII A subunit gene.

The short tandem repeat (STR) polymorphism present within the 5' untranslated region of the human coagulation factor XIII A subunit gene, HUMF13A01[AAAG]n, was evaluated using an allelic ladder, i.e., a standard size marker consisting of amplified alleles from the locus. The allelic ladder was constructed by pooling 12 polymerase chain reaction (PCR)-amplified alleles identified by their differential migration in denaturing polyacrylamide gel electrophoresis. This standard marker was used to distinguish 14 different alleles observed at this locus. Sequence analyses indicate that 13 of the alleles contain 4 through 16 iterations of the tandemly repeated AAAG sequence, respectively. The remaining allele carries four repeats and displays a deletion of two consecutive nucleotides (GT), one base distal to the repeat region. The allelic ladder was employed to type 326 F13A01 chromosomes rapidly and reliably in representatives of a German Caucasian population. Population data were analyzed with respect to Hardy-Weinberg Equilibrium (HWE) and compared with those of a previously studied Houston, Texas, Caucasian population.

Alleles↗

PCR-amplification of D2S44 alleles.

A strategy for PCR-amplification and sequencing of the flanking regions in the polymorphism D2S44 (YNH24) has been developed based on the investigations of Edwards et al. (1991). The flanking regions of the YNH24 probe were successfully amplified and two distinct PCR products with fragment sizes of 180 and 250 bp obtained. After asymmetric PCR and didesoxy-sequencing 60 bp could be determined for every PCR fragment. D2S44-specific primers were constructed which were located at the transition between the flanking and repeat regions. Amplification conditions were optimized using the YNH24 probe, different nuclease S1 concentrations and incubation times. Optimized conditions were applied to the amplification assay of human D2S44 alleles which had been investigated by RFLP analysis.

Alleles↗

Different types of structural variation in STRs: HumFES/FPS, HumVWA and HumD21S11.

Alleles of the STR systems HumFES/FPS, HumVWA and HumD21S11 were sequenced and analyzed. Sequence data revealed 3 different systems concerning the complexity of their sequence structure. HumFES/FPS belongs to the STR polymorphism with a simple repeat structure. Only 2 subtypes were found with a base substitution in the 5'-flanking region and no variation in the repeat region. In the STR system HumVWA the sequence structure of the repeat region is more complex, because 2 tetranucleotide units TCTA and TCTG were present. Additionally allele 14 revealed a completely different sequence structure leading to a different electrophoretic mobility. The repeat region of HumD21S11 is compound in structure. The possibility of variation at 3 positions leads to the occurrence of microheterogeneities in fragments of apparent length. In the upper allele range alleles arise with an additional incomplete TA-repeat.

Alleles↗

Medico-legal aspects of postmortem pink teeth.

While the phenomenon of pink teeth has been known since 1829, when it was first described by Bell, its application in forensic medicine has been limited. Recently, however, attention was again focused on pink teeth in legal cases. The medico-legal implication was the use of pink teeth as a possible means of evaluating the cause of death. Pink teeth can occur during life and postmortem. Except for very few and poorly documented exceptions, they develop earliest after 1 to 2 weeks postmortem. Their chemical analogy is seepage of hemoglobin or it's derivates into the dentinal tubules. Prerequisites are hyperemia/congestion and erythrocyte extravasation of the pulp capillaries, furthermore autolysis and a humid milieu. Therefore, they are most often associated with water immersion. The intensity of characteristics varies between different cases and also between different teeth in an individual case. Since the ante-mortem prerequisites are non-specific and can be replaced by certain postmortem conditions, there exist until now no specific correlation to the cause of death. The phenomenon is very often seen in victims of drowning where the head usually lies in a head-down position. From this it can be assumed that pink teeth even if not identical to postmortem lividity can, at least to some extent, be considered as analogous. Since, there is no obvious connection between the occurrence of pink teeth and the cause of death, it may be concluded that pink teeth are not pathognomonic for a specific cause of death and this is therefore an unspecific phenomenon.

Cause of Death↗

Locus ACTBP2 (SE33). Sequencing data reveal considerable polymorphism.

A total of 50 different ACTBP2 (human beta-actin related pseudogene) alleles and the cell line K562 were sequenced and analysed. Sequence data revealed not only length polymorphism but also a highly variable sequence polymorphism. 2 different sequence structures were characterised. Type I (223-259bp) contained the known regular 4bp repeat AAAG. Type II (265-309bp) revealed a further hexanucleotide unit AAAAAG in addition to the common AAAG which only occurs once in the repeat region. The position of this insertion showed considerable variation. To obtain a regular spaced allelic ladder 20 of the sequenced alleles were selected. Denaturing gels and high resolution/non-denaturing gels were compared and striking differences could be seen between the 2 gel systems. Separation of the alleles on a 6% denaturing gel and analysis on the ABI 373A Sequencer revealed fragment sizes which corresponded to the sequencing data but were in general 6-10bp longer. In contrast, in non-denaturing gels some alleles showed different electrophoretic mobilities compared to the sequenced allelic ladder which could indicate different fragment length and/or different sequence structure.

Actins↗

Population data and forensic efficiency values for the STR systems HumVWA, HumMBP and HumFABP.

Population studies were carried out on Caucasians from north-west Germany using the short tandem repeat (STR) systems HumVWA (locus: 12p12-12pter), HumMBP (locus: 18q23-pter) and HumFABP (locus: 4q28-q31). After electrophoresis 9 alleles could be identified for HumVWA in a sample size of 321 unrelated individuals and 4 alleles were found for HumFABP in 106 individuals. For HumMBP-A 10 alleles and for HumMBP-B 7 alleles and 1 intermediate allele were determined in a sample size of 143 individuals. No deviations from Hardy-Weinberg equilibrium could be observed. In a small family study (HumVWA-n = 129; HumMBP-n = 59; HumFABP-n = 48) no new mutations could be found for HumMBP-A and HumFABP whereas 2 mutations were found in HumMBP-B and one mutation in HumVWA. Positive results could be obtained from 1 ng-20 pg (HumVWA, HumFABP) and 1 ng-100 pg (HumMBP) template DNA.

Alleles↗

Comparison of different methods for CMV detection.

The submandibular glands were investigated in 77 cases of SIDS using histology, immunohistochemistry (IHC), in situ hybridization (ISH) and PCR to detect cytomegalovirus (CMV) inclusion disease. The aim of the investigation was to establish the detection of CMV by PCR as a model for the detection of other types of virus by PCR, especially for the detection of viruses which affect the respiratory system of babies. In 14 cases the CMV detection was possible. Typical changes of duct cells associated with CMV infection were observed in 9 by histology and in 4 further cases by IHC. In comparison to these methods, ISH showed a higher sensitivity but only one more positive case was found. Theoretically the PCR method is more sensitive than ISH and more convenient from the practical aspect. Detection of CMV by PCR was possible in 10 out of 14 positive cases. All PCR positive cases were cases showing an active disease but not latent infection.

Cytomegalovirus↗

Report of the European DNA profiling group (EDNAP)--towards standardisation of short tandem repeat (STR) loci.

This paper describes a collaborative exercise intended to demonstrate whether uniformity of DNA profiling results could be achieved between European laboratories using short tandem repeat (STR) loci. Two different STRs were chosen--HUMTH01 and the AT-rich HUMACTBP2 (SE33). The former locus has only five common alleles, whereas the latter is complex and has at least 30 alleles. Laboratories were asked to test seven blood stains and to report the results to the coordinating laboratory. The exercise demonstrated that the simple STR systems such as HUMTH01 are more amenable to adoption as standard loci than complex AT-rich systems.

Alleles↗

[Individualized DNA analysis in insurance medicine clarifications].

DNA investigations for the clarification of problems in insurance medicine can be subdivided into 3 groups (1) Traffic accidents (2) identification (3) questionable fraud cases. The development in individualisation by DNA analysis has progressed from the initial restriction fragment length polymorphisms (RFLPs) to the PCR-based polymorphisms. PCR systems are characterised by a very high sensitivity of detection and a high degree of success with highly degraded biological material. The current possibilities for DNA analysis are described and exemplified with special reference to PCR-based polymorphisms.

Accidents, Traffic↗