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Biomedical subjects

P Wiegand

Publications and source records attributed to P Wiegand.

46 records · Page 3Linked to original sources

pMCT 118 (D1S80): a new allelic ladder and an improved electrophoretic separation lead to the demonstration of 28 alleles.

Population data studies carried out on caucasians from Northwest Germany (n = 218) using the AMPFLP system pMCT 118 (D1S80). The method used in a previous study (Rand et al. 1992) for pMCT 118 could be improved by increasing the electrophoretic separation length from 10 to 20 cm and by using an extended allelic ladder which allowed the distinction of 8 additional alleles (a total of 28 alleles). Out of the 8 additional alleles 5 could be differentiated which differed within the 16 bp repeat sequence. The allele frequencies found were compared to population data from American caucasians, Hispanics and black Americans (Eisenberg and Maha 1991). All populations with the exception or black Americans, showed good agreement.

Alleles↗

DNA investigations on fetal material from paternity cases.

Three paternity cases have been investigated where DNA was extracted from fetuses (age: 8-10 weeks old) after interruption of pregnancy. In each case it was possible to clearly identify the putative father using 5 or 6 single locus probes (SLP's). Fetal bands (SLP) could be clearly identified from mixtures of placental and fetal DNA by comparison with the maternal and paternal bands. However, it was very difficult to resolve the fragment patterns of tissue mixtures with one multi locus probe (MLP), because of band overlap. Another advantage of using SLP's was that biostatistical calculations could be carried out and very informative Essen-Möller values for the probability of paternity were obtained.

Abortion, Therapeutic↗

Problems associated with the DNA analysis of stains.

Selected stain cases are presented which highlight various problems associated with DNA investigations on stain materials, especially risks of artefacts. These cases involve stain materials (blood, semen) which were exposed to different external conditions so that the DNA was partially degraded and of variable quantity. One multi locus probe (MLP) and 4-6 single locus probes (SLP's) were used for individualisation but artefacts such as extra bands, band deficiencies or shifts only occurred with the MLP. In one case where only a few spermatozoa were present in the vaginal swab, DNA extraction was carried out without preferential lysis to avoid loss of sperm DNA. The resulting mixed band pattern could be clearly attributed to the bands from the corresponding blood samples after SLP hybridisation.

Artifacts↗

Population and family data of RFLP's using selected single- and multi-locus systems.

The multi-locus systems (MLS) 33.15 and 33.6 (Jeffreys et al 1985a) and the single-locus systems (SLS) MS 1, MS 8, MS 31 and MS 43 (Wong et al. 1987) were investigated. The number of bands and the rate of band sharing were determined for both multi-locus systems and compared to the results of an English survey. Additionally 73 families were investigated using the multi-locus probes and the results compared to those obtained for the traditional blood grouping systems. The results were in full agreement so that no evidence of new mutations could be found. The fragment distribution was calculated for each of the 4 single-locus systems and compared to the values reported in an English survey (Smith et al. 1990b). Distinct discrepancies were seen in the systems MS 1 and MS 8. Family analyses were carried out for the 4 single-locus systems and compared to English data (Jeffreys et al. 1988) to look for any indications of possible new mutations. Only one isolated exclusion could be demonstrated with MS 1.

Chromosome Mapping↗

[Forensic efficiency of some highly polymorphic single locus systems].

The single locus probes MS 1, MS 8, MS 31 and MS 43 were investigated in combination with the restriction enzyme HINF I. The frequency distribution of fragment sizes detected by the polymorphic probe MS 8 was plotted for individuals from the Münster area and compared with an English survey. Clear discrepancies were found. The heterozygosity for the four systems was calculated and compared to the English figures. Only MS 8 showed a significant difference.

Alleles↗

[Applicability of the Jeffreys 33.15 and 33.6 multi-locus system].

A sample of 73 families which had been investigated by conventional paternity grouping was in addition subjected to DNA analysis using the multi locus systems 33.15 and 33.6. A comparison with the results of a conventional expert's opinion shows complete accordance. In cases showing exclusions in the conventional systems there were also exclusions by the multi locus systems and in cases without exclusions in the conventional systems no exclusions were found using multi locus probes. New mutations were not observed. In stain cases the resulting band patterns were often partially deficient. The problems in assigning such patterns with those observed in fresh samples are discussed.

Autoradiography↗

[Medicamentous sterility as a subterfuge in disputed paternity cases (author's transl)].

During forensic examination of male fertility in disputed paternity cases cheating is possible. There are substances with effects on spermatogenesis; on transport of spermatozoa and on hormonic regulation. Bis-dichloroacetyl-octamethylendiamine seems the most suitable. It has no side-effects, exept for an antabuse-effect. By daily treatment with 200 mg sterility starts after 2--3 months. After stopping the treatment fertility becomes normal after 2 months.

Contraceptive Agents, Male↗