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R Dirnhofer

Publications and source records attributed to R Dirnhofer.

At least 37 records · Page 2Linked to original sources
PubMed1999

Swiss Caucasian population data for 13 STR loci using AmpFISTR profiler plus and cofiler PCR amplification kits.

Allele and genotype frequencies for the 13 core STR loci (D3S1358, VWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317, D7S820, THO1, TPOX, CSF1PO, and D16S539) were determined in a Swiss Caucasian population sample (n = 206) using two commercially available multiplex PCR kits (AmpFISTR Profiler Plus and AmpFISTR Cofiler) and subsequent electrophoresis on an ABI PRISM CE 310 Genetic Analyzer instrument. All loci meet Hardy-Weinberg expectations. In addition, there is little evidence for association of alleles among the 13 loci. The allelic frequency data can be used in forensic analyses and paternity tests to estimate the frequency of a multiple STR locus DNA profile in the Swiss population.

Alleles↗
PubMed1999

Evaluation of prostate-specific antigen (PSA) membrane test assays for the forensic identification of seminal fluid.

Prostate specific antigen (PSA, also known as p30), a glycoprotein produced by the prostatic gland and secreted into seminal plasma, is a marker used for demonstrating the presence of seminal fluid. Methods for the detection of PSA include Ouchterlony double diffusion, crossover electrophoresis, rocket immuno-electrophoresis, radial immunodiffusion, and ELISA. The extremely sensitive ELISA technique can detect PSA in concentrations as low as approximately 4 ng/mL. However, all these techniques are cumbersome and time consuming to perform in forensic laboratories, especially when only a few samples per week are processed. Various membrane tests are currently used in clinical settings to screen a patient's serum for the presence of PSA at levels greater than 4 ng/mL. In this study we evaluated three immunochromatographic PSA membrane tests by analyzing semen stains stored at room temperature for up to 30 years, post-coital vaginal swabs taken at different time after intercourse, semen-free vaginal swabs, and various female and male body fluids, including urine. The data demonstrate that PSA membrane test assays offer the same sensitivity as ELISA-based tests and provide a rapid approach for the forensic identification of seminal fluid. Furthermore, when the supernatant from a DNA extraction is used for the assay, there is essentially no DNA consumption for determining the presence of PSA in a forensic sample.

Animals↗
PubMed1998

Detection of designer drugs in human hair by ion mobility spectrometry (IMS).

Since its inception in the early 1970s under the name plasma chromatography, ion mobility spectrometry (IMS) has undergone great changes. It is now utilized more and more in forensic science laboratories where it is used to detect explosives and environmental pollutants [1-4] as well as its use in detecting drugs of abuse [5-8]. Although IMS is known for nearly 30 years now [9], relatively few cases of the application of ion mobility spectrometry to the analysis of human hair have been reported [10-12]. The authors report a new and quick method to rapidly screen and determine MDMA ('ecstasy', 'Adam') and MDEA ('Eve') in human hair. The proposed method using trihexylamine as internal standard resulted in a rapid procedure useful in screening human hair specimens for designer drugs.

3,4-Methylenedioxyamphetamine↗
PubMed1997

Application of ion mobility spectrometry to the rapid screening of methamphetamine incorporated in hair.

Using ion mobility spectrometry (IMS), a simple, sensitive and rapid screening for methamphetamine (MA) incorporated in user's hair has been developed. To completely unbind MA from hair matrix and to achieve its effective vaporization for the IMS detection, the hair sample was digested in 5 M NaOH (methanol-water, 4:1, v/v) solution prior to IMS measurement. MA in hair was semi-quantitatively detected by monitoring the digested hair sample employing dibenzylamine (DBA) as internal standard. The minimum amount of hair sample required was 2 mg and its digested sample was ample for four IMS measurements. The detection limit of MA in hair was 0.5 ng mg(-1). This proposed method was applicable to the semi-quantitative detection of MA in users' hair samples, and to the sectional analysis for MA in a limited amount of user's hair. The IMS results obtained were in good agreement with their GC-MS determination.

Hair↗
PubMed1997

Fatal overdose of clozapine.

An ingestion of an unknown quantity of Leponex (clozapine) tablets in a suicide is described. Although clozapine is known for over 30 years now, relatively few cases of intoxications due to clozapine overdose have been reported. The authors report a new and quick method to analyze and determine the clozapine and N-desmethylclozapine concentration in body fluids. The analytes and an internal standard (zolpidem) were extracted from alkalinized samples into ethyl acetate before GC/NPD analysis. The proposed method resulted in a rapid procedure most useful in cases of deliberate poisoning with the neuroleptic drug Leponex.

Adolescent↗
PubMed1997

Effects of toluidine blue and destaining reagents used in sexual assault examinations on the ability to obtain DNA profiles from postcoital vaginal swabs.

Toluidine blue is an important tool to detect and document genital and perianal injuries following sexual assault. Application of toluidine blue dye and its subsequent removal from unstained areas by means of a destaining reagent, such as diluted acetic acid or a lubricant has been shown to increase the detection rate of posterior fourchette lacerations from 16% to 40% in adult rape victims. Currently, limited information on toluidine blue positive findings in sexually active control groups imposes some limitation on the interpretation of these injuries. Because injuries could otherwise be attributed to improper handling of an examination speculum or the improper insertion of the examining finger, the toluidine blue test should be performed prior to any digital or speculum examination and thus prior to the collection of forensic evidence. For forensic DNA identity testing, it becomes pertinent to determine whether toluidine blue and the destaining reagents used in a sexual assault examination have an adverse effect on the recovery of high molecular weight DNA from postcoital vaginal swabs and thereby have an impact on restriction fragment length polymorphism (RFLP) analysis or PCR-based tests. It is known that some of the lubricants used can have a destructive effect on sperm motility. In order to investigate the potential effects, postcoital vaginal swabs were taken 6 h after sexual intercourse and exposed directly to 1% toluidine blue in aqueous solution, 1-10% acetic acid, and various surgical and vaginal lubricants. Subsequently, the DNA was isolated and DNA identity typing (RFLP and PCR-based) was performed. The results demonstrate, that these reagents have no negative effect on the ability to obtain DNA profiles, either RFLP or PCR-based, from shallow and deep vaginal swabs. The quantity and quality of extractable high molecular weight DNA obtained was comparable with that from uncontaminated postcoital vaginal swabs. RFLP patterns and PCR-based typing results on the D1S80, HUMTH01, TPOX, and CSF1PO loci were consistent with the uncontaminated control swabs and the corresponding whole blood samples of the donors. Therefore, evidentiary material inadvertently contaminated with these reagents can be successfully typed.

Adult↗
PubMed1997

[Treatment failure from the viewpoint of forensic medicine].

It is the nature of a disease that it may not only improve but also deteriorate even when under medical treatment. Medical treatment thus constitutes a high-risk activity. The great advances in medical diagnosis and treatment in recent years have increased this risk still further. The medical profession is becoming increasingly unsettled and worried about claims of treatment errors, not least because-of the increasing pressure from the public and media. This has wrongly led to the development of "defensive medicine" such as has already started to become established in the USA. The medical expert should stand as a mediator between medicine and law, and thus be in a position to clear up misunderstandings between the two disciplines with their different mind sets. For these reasons, a forensic specialist should be appointed as an expert whenever possible; he may be proposed to the examining judge as an additional expert in the field in question to answer special questions put to him. This article discussed the basis on which an expert medical opinion should be provided in relation to an injury arising as a result of a treatment.

Defensive Medicine↗
PubMed1996

HLA-DQA1 subtyping data in the Swiss population.

Allele- and genotype frequencies for the polymerase chain reaction-based DNA genetic marker HLA-DQA1 were determined previously in a Swiss sample population (n = 200). In this study we subtyped the allele 4 in the same Swiss Caucasian population sample (distinguishing the 4.1 allele from the 4.2 and 4.3 alleles) using the AmpliType PM+ DQA1 PCR Amplification and Typing Kit. No deviations from Hardy-Weinberg equilibrium could be observed. The power of discrimination (Pd) of the HLA-DQA1 locus without subtyping the 4 allele for Swiss Caucasians was 0.931, when subtyping the 4 allele the value is 0.938. The frequency data can be used in forensic analyses to estimate the frequency of a HLA-DQA1 profile in the Swiss population.

Alleles↗
PubMed1996

Using multiplex PCR amplification and typing kits for the analysis of DNA evidence in a serial killer case.

Analysis of DNA evidence in a serial killer case was performed using the AmpliType HLA-DQ alpha-, AmpliType PM-, and the GenePrint STR Multiplex System PCR Amplification Kits. In addition, a sex typing procedure using the X-Y homologous gene amelogenin was carried out. DNA profiles from a single hair with attached sheath material, recovered from underneath the seat cover of the suspect's car seat were compared with DNA profiles derived from reference head hairs from a homicide victim. From the evidentiary sample only 9 ng of human DNA could be recovered. In a sample, where the quantity of DNA becomes a critical issue a powerful route is the simultaneous amplification of several loci (multiplex PCR). This is the first report where commercially available multiplex PCR amplification and typing kits have been introduced for the analysis of DNA evidence in a serial killer case and the analysis has been admitted in court.

Adult↗
PubMed1995

Swiss population data and forensic efficiency values on 3 tetrameric short tandem repeat loci-HUMTH01, TPOX, and CSF1PO-derived using a STR multiplex system.

Allele and genotype frequencies for 3 tetrameric short tandem repeat loci were determined in a Swiss population sample (n = 100) using the GenePrint STR Multiplex System, electrophoresis of the PCR products in DNA sequencing gels and subsequent detection of allelic fragments by silver staining. The loci are HUMTH01, TPOX, and CSF1PO. The observed heterozygosities are 83.0%, 60.0%, and 72.0%, respectively. The discrimination power determined for the individual loci is 0.914, 0.780, and 0.860, respectively, and the combined discrimination power for the triplex is 0.997. All loci meet Hardy-Weinberg expectations and after Bonferroni correction there was no evidence that the population sample deviates from expectations of independence. Moreover, independence of alleles at these STR loci with other PCR-based loci derived from the same Swiss population sample, previously reported, were considered. These loci were DQA1, LDLR, GYPA, HBGG, D7S8, GC and D1S80. Again, after Bonferroni correction there was no evidence that the population sample deviates from expectations of independence among alleles at the 10 different PCR-based loci. Thus, the allelic frequency data can be used in human identity testing to estimate the frequency of a multiple PCR-based DNA profile in the Swiss population.

Alleles↗
PubMed1995

A method for the purification and recovery of genomic DNA from an HLA DQA1 amplification product and its subsequent amplification and typing with the AmpliType PM PCR Amplification and Typing Kit.

DNA from plucked single hairs from ten individuals was extracted by two different methods and subsequently amplified and typed using the AmpliType HLA DQ alpha Forensic DNA Amplification and Typing Kit. The remaining untyped portions of the DQA1 amplification products were stored refrigerated or frozen for two weeks and subsequently purified using Centricon 100 microconcentrators. Genomic DNA was recovered from the DQA1 amplification PCR and used again as a template for a subsequent multiplex PCR. Twenty microL of each retentate were amplified and typed with the AmpliType PM PCR Amplification and Typing Kit. All typing results were consistent with DQA1 and PM results of control hairs and reference blood samples from the donors and all results were consistent with those obtained when the samples were typed solely for PM. The DQA1-Centricon 100-PM approach is useful when the genomic DNA from an evidentiary sample has been used completely for HLA-DQA1 typing, so that only the amplified product is remaining. The typing of five more genetic markers can be achieved from a HLA-DQA1 sample, so additional information for identification purposes could be provided. However, genomic DNA as well as the DQA1 product are recovered and the latter will also serve as a template in the subsequent PM amplifications. Therefore there will be more DQA1 product after the PM amplification than would be expected when only genomic DNA was used as a template. Thus certain practices should be considered when reading the types from PM probe strips if this DQA1-Centricon 100-PM approach is used.

DNA↗
PubMed1995

Confirmation of the identity of human skeletal remains using Multiplex PCR Amplification and Typing Kits.

The identify of human skeletal remains found in a wooded area approximately one year after the person was reported missing was provisionally established by routine methods and circumstantial evidence. Multiplex PCR systems--the AmpliType PM PCR Amplification and Typing Kit and the GenePrint STR Triplex Amplification and Typing Kit--were used to confirm the identification. DNA profiles from femur bone from the remains were compared with profiles derived from head hairs from a hairbrush recovered in the missing woman's apartment. In addition, a sex typing procedure using the X-Y homologous gene amelogenin was carried out. This is the first report of a case using commercially available multiplex PCR amplification and typing kits to confirm the identity of skeletal remains.

Bone and Bones↗
PubMed1994

Swiss population data on the loci HLA-DQ alpha, LDLR, GYPA, HBGG, D7S8, Gc and D1S80.

Allele and genotype frequencies for seven polymerase chain reaction-based DNA genetic markers were determined in a Swiss sample population. The loci are D1S80, HLA-DQ alpha, low density lipoprotein receptor, glycophorin A, hemoglobin G gammaglobin, D7S8, and group-specific component. All loci meet Hardy-Weinberg expectations. In addition, there is no detectable association of alleles between loci. The frequency data can be used in forensic analyses and paternity tests to estimate the frequency of a DNA profile in the Swiss population.

DNA↗
PubMed1994

Swiss population data on three tetrameric short tandem repeat loci--VWA, HUMTHO1, and F13A1--derived using multiplex PCR and laser fluorescence detection.

Allele and genotype frequencies for 3 tetrameric short tandem repeat loci VWA, HUMTHO1, and F13A1 were determined in a Swiss population sample using multiplex PCR and subsequent electrophoresis in DNA sequencing gels processed by automated laser fluorescence detection. The technique allows single base pair resolution and rapid typing, with a concomitant reduction in the potential for human transcriptional typing errors. All loci meet Hardy-Weinberg expectations. In addition, there is little evidence for association of alleles among the 3 loci. The allelic frequency data can be used in forensic analyses and paternity tests to estimate the frequency of a multiple STR locus DNA profile in the Swiss population.

Alleles↗
PubMed1993

Effects of nonoxinol-9 on the ability to obtain DNA profiles from postcoital vaginal swabs.

Nonoxinol-9, the active ingredient of many spermicide foams and creams, has been shown to inactivate effectively high titres of HIV in vitro. Therefore the early administration of nonoxinol-9, perhaps by a rape victim herself, has been suggested as a potential prophylactic therapy for prevention of a possible HIV infection. For forensic DNA identity testing, it becomes pertinent to determine whether nonoxinol-9 could have an adverse effect on the recovery of high molecular weight DNA from postcoital vaginal swabs and thereby have an impact on restriction fragment length polymorphism (RFLP) analysis. If high molecular weight DNA can not be recovered, it may still be possible to proceed with analyses using PCR-based tests. In order to investigate the potential effects of nonoxinol-9, inserts, gels, or sponges containing nonoxinol-9 were applied either 15 min pre- or 15 to 60 min post coitus. Postcoital vaginal swabs were taken one and six h after sexual intercourse, the DNA was isolated and DNA identity typing was performed. The results demonstrate that nonoxinol-9 has no negative effect on the ability to obtain DNA profiles, either RFLP or PCR-based, from postcoital vaginal swabs. The quantity of extractable high molecular weight DNA obtained (as determined by slot-blot analysis) was comparable with that from uncontaminated postcoital vaginal swabs. RFLP patterns and PCR-based typing results at the HLA-DQ alpha and D1S80 loci from the nonoxinol-9 treated swabs were consistent with the uncontaminated control swabs and the corresponding whole blood samples of the donors. Therefore an early prophylactic administration of the topical anti-HIV agent nonoxinol-9 is not an impedient for obtaining DNA profiles from evidentiary material.

Coitus↗
PubMed1992

[Population genetic Hae III/RFLP and HLA-DQ-alpha data of a Caucasian population sample in Switzerland].

DNA from unrelated individuals (Caucasians; n = 200-271) from Switzerland were digested with Hae III and successively hybridized to the DNA probes D1S7, D2S44, D4S139, D10S28, D14S13, D17S26 and D17S79. An allele frequency distribution was determined for each locus. Furthermore, from the same individuals (n = 200) after amplification of DNA the allele and genotype frequencies at the HLA-DQ alpha locus were determined. The allele frequency distribution in Swiss Caucasians is statistically similar to American Caucasian population samples. In criminal cases a DNA-profile derived from four single-locus probes always leads to a very high value of discrimination and in paternity testing the probability of paternity always exceeds 99.9% regardless to the reference population used for biostatistical evaluation. Therefore for use in forensic analysis and paternity testing pooled caucasian databases might be used for the determination of the frequency of occurrence of a DNA-profile.

Alleles↗
PubMed1992

[Conversion of forensic paternity determination to DNA analysis].

For many years, the resolution of disputed paternity cases by genetic means relied on laboratory blood tests of red cell antigens and red cell and serum protein electrophoresis. These systems are generally characterized as lacking polymorphism and having low powers of exclusion, therefore it was necessary to use a panel of up to 23 marker systems. Over the past five years, a variety of DNA restriction fragment length polymorphism (RFLP) systems have been developed that characterize individuals at the DNA level. In this paper we describe the implementation of a Hae III RFLP system utilized in our laboratory for the resolution of disputed parentage cases as well as forensic casework. Since the analysis of highly polymorphic VNTR loci has proven to be the most powerful method to date for the determination of biological relatedness the utilization of the conventional methodologies should be completely replaced.

Adult↗