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Biomedical subjects

M Klintschar

Publications and source records attributed to M Klintschar.

At least 19 recordsLinked to original sources

DNA polymorphisms in the tyrosine hydroxylase and GNB3 genes: association with unexpected death from acute myocardial infarction and increased heart weight.

Sudden and unexpected death from myocardial infarction (MI) is one of the most commonly observed findings in forensic medicine. To investigate the biochemical and genetic background of this disease we investigated the genotypes for two polymorphisms associated with hypertension: TH01, a tetrameric microsatellite in the tyrosine hydroxylase gene and the single nucleotide polymorphism C825T in the GNB3 gene in 116 sudden deaths from MI (78 males, 38 females) and in a control group of 137 deaths from natural causes other than MI (52 males, 85 females). For TH01 no correlation with the prevalence of MI was found. For C825T, results were different. While for the male individuals allelic frequencies and genotype distributions were similar in both groups, T-homozygosity was significantly more common in female fatalities from MI than in the female control group (24% versus 7%; Relative Risk 2.29). Nevertheless, neither for TH01 nor for C825T an association with heart weight was found. Thus our results demonstrate that the C825T polymorphism may play a role in the development of myocardial infarctions, at least in females. They also demonstrate that the genetic component in complex diseases like MI may depend on the gender of the patients. As the influence of this polymorphism on arterial blood pressure appears to be relatively small, and G-proteins are involved in numerous intracellular signal cascades it can be speculated that T-homozygosity at this locus might influence the incidence or mortality of cardiovascular disease via hitherto unknown mechanisms.

Adult↗

Sudden cardiac death in hereditary hemochromatosis: an underestimated cause of death?

Hereditary hemochromatosis (HH) is a frequent autosomal recessive disease which causes iron-overload of various organs. Of all northern European affected individuals, 90-95% show 1 of 3 known point mutations in the HFE gene. Symptoms and organs involved can vary considerably: Only a small fraction of the 200,000-400,000 persons affected in Germany develop the classical picture of liver cirrhosis and/or pancreatic fibrosis. Nevertheless, the life expectancy of persons with moderate or even subclinical symptoms is reduced, in many cases due to myocardial damage leading to cardiomyopathy with greatly increased risk of sudden cardiac death. Although the high prevalence of HH suggests that sudden cardiac death due to cardiac HH is a relatively common cause of death, the forensic literature lacks such reports. We present the case of sudden cardiac death in a young man with histological findings of massive cardial hemochromatosis which is characterized by the fact that none of the three known mutations for HH were found. This case demonstrates that genetic screening alone might not be sufficient to identify all persons at risk to developing HH.

Adult↗

Persisting fetal microchimerism does not interfere with forensic Y-chromosome typing.

Forensic Y-chromosome typing applies Y-chromosomal polymorphisms to the analysis of male/female mixed stains such as vaginal swabs in rape cases. The sensitivity of this approach exceeds that of cytological techniques combined with autosomal DNA typing. Y-chromosome typing is based on the assumption that Y-chromosomal DNA found in tissue or secretions of women must originate from a male individual, usually the perpetrator. Nevertheless, it was shown recently that fetal cells can migrate into the female body during pregnancy and can persist for decades ("persisting fetal microchimerism"). The body of a woman after a pregnancy with a male embryo can thus display a small fraction of fetal cells with Y-chromosomes. Using high sensitivity PCR protocols (reamplification with nested primers and up to 60 PCR cycles) fetal cells were previously identified in a number of maternal tissues including skin, blood, muscle and solid organs. It is, however, not clear at present, whether these cells can occur in vaginal secretions, and whether they are capable of producing false positive results in forensic Y-chromosome typing. To evaluate these questions, 66 blood samples of women with at least one son and nine vaginal swabs of women without sexual intercourse in the last 2 weeks were amplified for a stretch of the SRY gene. Eight thyroid gland tissues with already established male fetal microchimerism were used as positive control samples. Blood samples of 10 young girls without history of pregnancy were used as negative controls. Using a PCR with 10 ng of extracted DNA and 30 PCR cycles ("routine sensitivity assay") none of the samples yielded positive results. However, in a PCR with 200 ng of extracted DNA and 45 PCR cycles ("high sensibility assay"), 14% of the blood samples of mothers and 33% of the vaginal swabs amplified for SRY. Our results thus show that increasing the sensitivity of the PCR method and the amount of template DNA produce positive results while protocols used for routine Y-chromosomal typing with small amounts of DNA (approximately 10 ng of DNA) and with a limited number of PCR cycles (approximately 30) can clearly eliminate this peril.

Case-Control Studies↗

Fatal truck-bicycle accident involving dragging for 45 km.

Vehicle-bicycle accidents with subsequent dragging of the rider over long distances are extremely rare. The case reported here is that of a 16-year-old mentally retarded bike rider who was run over by a truck whose driver failed to notice the accident. The legs of the victim became trapped by the rear axle of the trailer and the body was dragged over 45 km before being discovered under the parked truck. The autopsy revealed that the boy had died from the initial impact and not from the dragging injuries which had caused extensive mutilation. The reports of the technical expert and the forensic pathologist led the prosecutor to drop the case against the truck driver for manslaughter.

Accidents, Traffic↗

D1S1171: a new highly variable short tandem repeat polymorphism.

This study reports the evaluation of the STR locus D1S1171 (GDB: 312934) for forensic purposes, which was investigated by PCR amplification and native polyacrylamide gel electrophoresis in 141 unrelated Austrians. No deviations from Hardy-Weinberg expectations were observed. The mean exclusion chance (MEC) was 0.677, the discriminating power (DP) was 0.951 and the observed heterozygosity rate was 0.853. An allelic ladder consisting of 10 sequenced alleles (96-132 bp) was constructed. Sequence analysis revealed a GAAA repeat motif. According to the number of tetranucleotide repeats the smallest allele was designated 9 and the largest allele 18.

Alleles↗

Significant differences between Yemenite and Egyptian STR profiles and the influence on frequency estimations in Arabs.

A population genetic study was performed on Yemenites using the set of nine short tandem repeat loci (STRs) D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820. Analysis of the data revealed that all loci were in Hardy-Weinberg equilibrium and evidence of linkage equilibrium was found for only 1 out of 36 locus pairs. At seven loci the allelic distributions found in the Yemenite sample were significantly different from those found for an Arab population sample from Egypt. Nevertheless, we assume that the Yemenite database can be used for Arabs of unknown or foreign (non-Yemenite) origin in the absence of population-specific databases without exerting a significant bias on the biostatistical interpretation. In an experimental set-up (ethnic profile frequency ratio test), the impact of calculating multi-locus profile frequencies for foreign Arab individuals (Egyptians) using the Yemenite database instead of a region-specific one was negligible.

Arabs↗

Evidence of fetal microchimerism in Hashimoto's thyroiditis.

Fetal microchimerism, the engraftment of fetal progenitor cells into maternal tissues, has been implicated in the etiology of autoimmune diseases. We used PCR analysis to determine whether microchimerism occurred in the thyroid glands of female patients suffering from Hashimoto's disease and thus may be involved in its etiology. PCR amplification was performed from thyroid gland specimens using primers unique to a Y-chromosomal sequence (SRY gene) and primers for a sequence that is Y/X-chromosomal homologous except for a 6-bp deletion in the X-chromosomal sequence (amelogenin). Microchimerism was detected in 8 of 17 Hashimoto patients, but in only 1 of 25 controls (nodular goiters). Both groups were of similar age and had comparable numbers of pregnancies and numbers of sons. All individuals with microchimerism had given birth to at least 1 son. Our results show that microchimerism is significantly more common in Hashimoto patients than in patients suffering from nodular goiter. We therefore suggest that microchimerism might play a role in the development of Hashimoto's disease, although we cannot completely eliminate the hypothesis that microchimerism is just an "innocent bystander" in a process triggered by other mechanisms.

Adult↗

Evaluation of an alkaline lysis method for the extraction of DNA from whole blood and forensic stains for STR analysis.

A modified alkaline lysis protocol for extracting DNA from forensically relevant specimens is evaluated and compared with the chelex 100 method. For whole blood, bloodstains and sperm stains, both methods yielded comparable results after amplification for a pentameric STR locus (HumCD4). The main advantages of the new method are: only approximately ten minutes and two pipetting steps are necessary and the expenses for the extraction are extremely low as only NaOH, TrisHCl buffer and a single microcentrifuge tube are required. Alkaline lysis also proved to yield DNA suitable for typing longer STRs by using dye-labeled primers and capillary electrophoresis. These advantages should render this protocol especially interesting for high-throughput laboratories in combination with multiplex PCR and fluorescent dye technology, although the storability of the extracts proved to be problematic.

Blood Chemical Analysis↗

Colchicine poisoning by accidental ingestion of meadow saffron (Colchicum autumnale): pathological and medicolegal aspects.

Although intoxications with colchicine, the alkaloid of Colchicum autumnale (meadow saffron), are well known, in most cases the intoxications are evoked by oral or parenteral preparations traditionally used as medication against gout. The accidental ingestion of Colchicum autumnale, on the other hand, is a rare event and has to our knowledge only twice been described in detail. We report a further case in which two persons confused this highly poisonous plant with wild garlic (Allium ursinum), a popular spice in the Central European cuisine. While one person merely complained about a 3-day episode of nausea, vomiting and watery diarrhea, the second person died of multi-organ system derangements 48 h after the ingestion of the colchicum leaves. At autopsy hemorrhagic lung oedema, hypocellular bonemarrow, centrilobular fatty necrosis of the liver and necrosis of the proximal convoluted tubuli of the kidneys were observed. A colchicine concentration of 7.5 micrograms/ml was found in the bile whereas no substance was detected in the postmortem blood.

Accidents↗

Population genetic studies on the tetrameric short tandem repeat loci D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820 in Egypt.

The short tandem repeat loci (STRs) D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820 and a locus allowing for sex-discrimination (amelogenin) can be co-amplified by the polymerase chain reaction using a commercially available kit (AmpFlSTR Profiler plus, Perkin-Elmer Biosystems, San Jose, CA) and subsequently typed using capillary electrophoresis (ABI Prism 310 Genetic analyzer, Perkin Elmer Applied Biosystems, San Jose CA). To establish databases for these loci for an Arab population sample from Egypt, 140 unrelated persons were typed. Analysis of these data revealed that all loci except for VWA were in Hardy-Weinberg equilibrium, that the combined mean paternity exclusion chance (MEC) was 0.999875 and that the combined discriminating power (DP) was 2.635 x 10(-11). The allelic distributions found in the Egyptian sample were significantly different at four loci from those found for an Austrian Caucasian population, at all nine loci from an African-American sample and at six of six loci from a Chinese sample. No evidence of linkage equilibrium between any of the co-amplified loci was found. Our results support that the combination of multiplex PCR and capillary electrophoresis can both save time and yield excellent results for paternity testing and stain analysis.

Alleles↗

Separation of sperm and vaginal cells based on ploidy, MHC class I-, CD45-, and cytokeratin expression for enhancement of DNA typing after sexual assault.

BACKGROUND: Successful DNA typing after rape is limited when only a few sperm and numerous vaginal cells are recovered from a swab, resulting in an extremely unfavorable ratio of male to female DNA. The goal of this study was to develop a protocol involving sperm cell sorting with flow cytometry based on differences in ploidy, major histocompatibility (MHC) class I, CD45 and cytokeratin expression. METHODS: Vaginal lavages were mixed with serially diluted ejaculate. After immunostaining and stoichiometric nuclear staining, spermatocytes were isolated by fluorescence-activated cell sorting. All sorted cells were used for DNA extraction and subsequent quantitative fluorescent multiplex polymerase chain reaction. The preferential lysis was performed for comparison. RESULTS: The sorting procedure was superior to the preferential lysis method within all tested dilutions. One documented case of rape was examined with both procedures and only after cell sorting with flow cytometry was the male DNA identified. CONCLUSIONS: We were able to show that separation of sperm and vaginal cells using cell sorting with flow cytometry may be crucial when there is only a few sperm detectable after rape.

Cell Separation↗

Population genetic studies on nine tetrameric short tandem repeat loci using fluorescence dye-labeled primers and capillary electrophoresis in the Austrian population.

The short tandem repeats (STR) D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820 and a locus allowing sex discrimination (amelogenin) can be coamplified by the polymerase chain reaction using a commercially available kit, and subsequently typed using capillary electrophoresis. To establish databases for these loci for Austrian Caucasians, 115 unrelated persons were typed. All loci were in Hardy-Weinberg equilibrium. The combined mean paternity exclusion chance (MEC) was 0.999891 and the combined discriminating power (DP) was 3.08 x 10(-11). The allelic distributions showed no differences to those found for other Caucasian populations. Our data differed significantly from an Afro-American population at 5 loci and from a Chinese population at 4 loci. Linkage disequilibrium between any of the coamplified loci was not evident. Thus the combination of multiplex PCR and capillary electrophoresis can save time and yield excellent results for paternity testing and stain analysis.

Austria↗

Characterization of a highly variable short tandem repeat polymorphism at the D2S1242 locus.

We report the evaluation of short tandem repeat (STR) locus D2S1242 (GDB ID G00-309-429) for forensic purposes, investigated by polymerase chain reaction (PCR) amplification and both native and denaturating polyacrylamide gel electrophoresis in 147 unrelated Austrians. No deviations from Hardy-Weinberg expectations were observed. The mean exclusion chance (MEC) was 0.669, the discriminating power (DP) was 0.947, and the observed heterozygosity rate was 0.856. An allelic ladder consisting of eight sequenced alleles (141-167 and 175 bp) was constructed. Sequence analysis revealed that the locus comprised two repeat motifs varying in number between alleles GAAA and GAAG. According to the number of tetranucleotide repeats the smallest allele was designated as 10 and the largest allele as 18.

Alleles↗

Modified primers for D12S391 and a modified silver staining technique.

In this paper we describe a new primer pair for the short tandem repeat (STR) D12S391 which makes it possible to obtain considerably shorter amplification fragments (125-173 bp), compared to the previously published primers (205-253 bp). The primers were tested on 70 samples with known genotypes, and no differing results were found. In sensitivity studies, forensic casework samples and DNA quality studies, we proved that the new primers can improve the efficiency of the amplification. Moreover, the resolution of this locus on denaturing PAGE followed by silver staining was dramatically improved. This improvement was found to be most valuable for typing the rare.3 variants known for this locus. We also present and propose a new method for silver staining denaturing acrylamide gels.

Alleles↗

Separation of sperm and vaginal cells with flow cytometry for DNA typing after sexual assault.

BACKGROUND: Successful DNA typing after rape is limited when only a few sperm and numerous vaginal cells are recovered from a swab, resulting in an extremely unfavorable ratio of male to female DNA. The goal of this study was to develop a protocol involving sperm cell sorting with flow cytometry based on differences in ploidy, major histocompatibility class I, CD45, and cytokeratin expression. METHOD: Vaginal lavages were mixed with serially diluted ejaculate. After immunostaining and stoichiometric nuclear staining, spermatocytes were isolated by fluorescence-activated cell sorting. All sorted cells were used for DNA extraction and subsequent quantitative fluorescent multiplex polymerase chain reaction. The preferential lysis was performed for comparison. EXPERIENCE: The sorting procedure was superior to the preferential lysis method within all tested conditions. In unfavorable dilutions, the male DNA could be identified only after cell sorting with flow cytometry. CONCLUSION: We were able to show that separation of sperm and vaginal cells using cell sorting with flow cytometry may be crucial when there are only microtraces of sperm detectable after rape.

Adult↗

Two case studies of chronic idiopathic neutropenia preceding acute myeloid leukaemia.

Chronic idiopathic neutropenia is regarded as a benign disorder without risk of malignant transformation. We present two patients with chronic idiopathic neutropenia who showed disease progression to acute myeloid leukaemia. Sequence analysis of the granulocyte-colony stimulating factor receptor (G-CSFR) gene from leukaemic DNA did not reveal any mutations and microsatellite analysis provided no evidence of microsatellite instability or loss of constitutional heterozygosity. These case studies suggest that chronic idiopathic neutropenia may constitute a preleukaemic condition in some patients. Alterations of the G-CSFR or defective DNA mismatch repair do not appear to be involved in malignant transformation.

Acute Disease↗

Genetic variation at the STR loci D12S391 and CSF1PO in four populations from Austria, Italy, Egypt and Yemen.

The short tandem repeat systems (STRs) D12S391 and CSF1P0 were amplified by the polymerase chain reaction (PCR) on blood samples from 100 to 158 unrelated Austrians, Italians, Yemenians and Egyptians. The samples were analyzed by both native and denaturing electrophoresis and two primer pairs were tested for the CSF1PO locus. Except for the CSF1PO data on the Egyptians, no deviations from the Hardy-Weinberg equilibrium were detected. For D12S391, no significant differences were found between the two Arab populations and between the two European populations, but the differences between both Arab populations and the Italians were significant. For CSF1PO, differences were only observed between the Yemenians and all three other populations. No evidence of linkage disequilibrium between the two STRs was found. The observation of a D12S391 allele consisting of only 14 repeats was confirmed by sequencing.

Alleles↗