Detection of saliva traces using test strips

The test strip Rapignost-Amylase (Behring) for the rapid determination of alpha-amylase in the urine is also suitable for the determination of salivary amylase in stains stored up to 6 weeks at room temperature. The stains are extracted with physiological saline (extraction time 30 min), then the application zone of the strip is wetted with the extract. Positive amylase-reaction is recognised as a reddish-violet colouration of the reaction zone. Biological stains with low amylase concentrations (urine semen, vaginal secretion, mucus) react amylase negative. The method is uncomplicated and can be completed within 30 min. The test strips are easily available and stable during storage. Therefore the determination of saliva with test strips should be preferred to the clinical methods if the storage times of the stain are not longer than 4-6 weeks. It is a suitable procedure to determine salivary stains for use in forensic biology.     

The zinc test as an alternative for acid phosphatase spot tests in the primary identification of seminal traces

The value of the acid phosphatase spot test in the primary visualization and identification of seminal traces is hampered by the sensitiveness of the enzyme to biodegradation. An alternative spot test is proposed, based on the high concentration of the more stable zinc metal in seminal plasma. The proposed zinc spot test is simple and suitable for on site investigation. Although the sensitivity in fresh stains is lower than that of the acid phosphatase spot test, this is largely compensated by the lower sensitiveness to biodegradation. The specificity for semen is higher than that of the acid phosphatase spot test. In vaginal swabs it was nevertheless seen, that samples should be taken within 24 h after alleged sexual assault to give reliable results.     

检验人精浆特异蛋白P30免疫胶体金试剂条的研制

目的制备用于检验人精浆特异蛋白P30-主要是来自法医学案件的免疫胶体金层析试剂条.方法选取针对不同抗原决定簇的抗P30单克隆抗体细胞株,并制备其小鼠腹水,分离纯化单克隆抗体.制备胶体金并以纯化抗体包被,制成免疫胶体金,以免疫胶体金浸泡玻璃纤维.选取适宜的硝酸纤维素膜并于其上不同位置以未金标的另一株P30单克隆抗体和羊抗鼠IgG包被.搭建试剂条并检测其灵敏度和特异性.结果所制成的试剂条灵敏度至少可达4ng/ml;对6人份混合的人精液物质在稀释20万倍后仍出阳性结果,且无非特异性反应.结论检验人精浆特异蛋白P30的免疫胶体金试剂条可对嫌疑人精物质做出排查,有利于法医物证检验.     

A more sensitive method for the quantitation of genomic DNA by Alu amplification

Current procedures for human DNA quantitation reach their limit at 150 pg DNA, which is above the limit of the PCR profiling range using Profiler-Plus (Applied Biosystems, CA). This study tested the potential for the use of primate specific Alu sequences in forensic science for the sensitive detection and quantitaion of DNA. A fluorescently labelled primer pair was designed enabling high efficiency amplification of the core Alu sequence within primate DNA. Quantitation was performed by measurement of fluorescence intensity and comparison to a series of standard template DNA amounts via the construction of a standard curve. The new Alu-based quantitation protocol developed has shown its feasibility in more sensitively quantitating (100-2.5 pg) unknown amounts of human DNA for forensic use. The method is compatible with the use and throughput of current forensic procedures.     

Determination of lysergic acid diethylamide in body fluids by high-performance liquid chromatography and fluorescence detection--a more sensitive method suitable for routine use

A new method for determination of lysergic acid diethylamide (LSD) in body fluids by high-performance liquid chromatography and fluorescence detection was developed based on previously published methods. The new method is suitable for confirmation of samples tested positive by immunoassay, avoiding loss of LSD by absorption to surfaces. The reduced loss of LSD results in improved sensitivity. This is achieved by adding ethylene glycol to the samples, which cover glass surfaces. This principle can similarly be used to improve analysis of other drugs. Body fluids for analysis included urine and whole blood. An internal standard was applied for quantification of LSD. The new method offers satisfying precision data and has a detection limit of less than 0.05 ng/nL.     

The LAP test. A new method for identification of seminal stains by a qualitative color reaction of leucine aminopeptidase.

A new simple method for identification of seminal stains is described. It employs a qualitative color reaction based on histochemical technique for demonstration of leucine aminopeptidase (LAP), which is extremely abundant in human semen. The method herein reported (the LAP test) is quite suitable for medicolegal examination of seminal stains as a preliminary test.     

抗人血红蛋白胶体金检测试剂条的研制

目的制备法医学检验所用的确定人血的免疫胶体金层析试剂条。方法选取抗人血红蛋白单克隆细胞株,制备其小鼠腹水,从腹水中纯化出单克隆抗体。制备胶体金并用一纯化的单克隆抗体包被,制成免疫胶体金。取玻璃纤维以免疫胶体金浸泡,烘干。在一硝酸纤维素膜上两个不同位置分别点加另一抗人血红蛋白抗体和羊抗鼠IgG。搭建试剂条并检测其灵敏度和特异性。结果制成的免疫胶体金试剂条可对稀释至20万倍的人血红蛋白溶液显示阳性,对法医学检验常见8种动物的血溶液显示阴性。结论所制备抗人血红蛋白胶体金试剂条可以应用于法医学检验。     

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.     

gamma-Glutamyltransferase test as a new tool for identification of seminal stains

A simple qualitative method for identification of seminal stains based on a high activity of gamma-glutamyltransferase (gamma-GTP) in human semen is described. It employs the release of alpha-naphthylamine from N-gamma-glutamyl-alpha-naphthylamide by the gamma-GTP action: alpha-naphthylamine couples with Fast Garnet GBC salt to produce a strong brownish-red color. The data on its simplicity, specificity, and stability show that the present method is suitable for medicolegal examination of seminal stains as a preliminary test.     

Zinc test as a new tool for identification of human seminal stains

An extremely simple qualitative method for identification of seminal stains based on high levels of zinc in human semen is described. It uses reaction of 1-(2-pyridylazo)-2-naphthol with zinc to develop a deep red color. The data are presented on the sensitivity, stability and specificity of the present method. We can recommend it for identification of human semen especially in old or denatured samples.     

Use of amelogenin test for DNA sex appurtenance in analysis of mixed biological traces

Theoretical and experimental study of amelogenin tests system for identification of DNA sex appurtenance has been performed. In many cases amplification can fail to reflect the true quantitative ratio between the mixture components during typing sex-specific variants of amelogenin gene in DNA preparations of mixed sex appurtenance. In practical studies these properties of the amelogenin system can lead to difficulties and errors in interpretation of the results of forensic medical expert evaluations, and we therefore studied the use of amelogenin DNA test for identification of sex appurtenance of mixed biological traces and compared the characteristics of autosomal PDAF system and amelogenin system for sex identification in analysis of DNA mixtures.     

Comparative study of the sensitivity and specificity of the zinc and acid phosphatase spot tests for the detection of seminal stains

The sensitivity and specificity of a zinc spot test for the detection of semen were compared with those of an acid phosphatase detection method. As screening techniques both tests were found to be very sensitive, but the zinc test was more specific and was more reliable in older and especially in deteriorated specimens. It is concluded that the zinc spot test deserves at least the same place as the acid phosphatase test in the primary investigation of suspected semen stains and might well be the test of choice in older and poorly preserved stains.     

Evaluating the sensitivity,stability, and cross-reactivity of commercial fentanyl immunoassay test strips

Illicit fentanyl has flooded the United States' drug market, increasing the risk of overdose and poisonings throughout the general population and accidental exposure among law enforcement officers confiscating the increasing number of seizures. Fentanyl test strips (FTS) are used to obtain presumptive information about the presence of fentanyl in a suspected sample. However, their adoption by law enforcement personnel and seized-drug analysts has been limited because most products are advertised for urine testing, not for assays using water solutions. This study presents an evaluation of four commercial FTS: Rapid Response from BTNX, Inc.; T-Dip Fentanyl (FTY) Urine Dip Cards obtained from Amazon.com ; Premier BioDip FYL10 from Premier Biotech Inc.; and MobileDetect Fentanyl strips from DetectaChem, Inc. Performance characteristics curves were used to compare the products' sensitivity, showing that all can reliably detect fentanyl in aqueous solutions at concentrations below 1 μg/mL, with some of the tests able to reliably detect the drug at 200 ng/mL. A stability study demonstrates the performance of all four FTS brands was only slightly affected after 30 days of storage at two extreme environmental conditions. Fentanyl-related substances are also evaluated using the Rapid Response FTS, which showed high cross-reactivity with para-fluorofentanyl and acetylfentanyl, but lower with ortho-chlorofentanyl, carfentanil, and 4-ANPP. Users should be aware that FTS may give false-negative results even when potentially dangerous levels of carfentanil are present. When testing other common drugs, adulterants, and diluents frequently encountered in seized tablets, concentration-dependent results were obtained and multiple instances of false positives were recorded.     

An extremely sensitive species-specific ARMS PCR test for the presence of tiger bone DNA

The survival of the tiger (Panthera tigris) is seriously threatened by poaching to provide raw materials for traditional Chinese medicines (TCMs). Most highly prized are the tiger's bones, which are used in combination with other animal and plant derivatives in pills and plasters for the treatment of rheumatism and other ailments. Hundreds of patent remedies have been produced which claim to contain tiger bone, but proof of its presence is needed if legislation prohibiting the trade in endangered species is to be enforced.A highly sensitive tiger-specific real-time PCR assay has been developed to address this problem. Using primers specific to the tiger mitochondrial cytochrome b gene, successful amplification has been reliably achieved from blood, hair and bone as well as from a range of TCMs spiked with 0.5% tiger bone. Although capable of detecting fewer than 10 substrate molecules, the seven varieties of TCM pills and plasters tested showed no detectable trace of tiger DNA before spiking. Furthermore, sequencing several "tiger bone" fragments seized from TCM shops has shown that they actually originated from cattle and pigs. The potential effects of traditional bone preparation methods, evidence that much lower concentrations are used than alleged on TCM packaging, and substitution of bones from other species all suggest a low likelihood of detecting tiger DNA in patent medicines. Despite this, the basic methods have been thoroughly proven and can be readily applied to derivatives from other Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) protected species, providing a rapid and highly sensitive forensic test for species of origin. Potential applications to the monitoring of wild populations are demonstrated by the successful identification of shed hairs and faecal samples.     

An extremely sensitive species-specific ARMs PCR test for the presence of tiger bone DNA

The survival of the tiger (Panthera tigris) is seriously threatened by poaching to provide raw materials for Traditional Chinese Medicines (TCMs). Most highly prized are the tiger's bones, which are used in combination with other animal and plant derivatives in pills and plasters for the treatment of rheumatism and other ailments. Hundreds of patent remedies have been produced which claim to contain tiger bone, but proof of its presence is needed, if legislation prohibiting the trade in endangered species is to be enforced. A highly sensitive tiger-specific real-time PCR assay has been developed to address this problem. Using primers specific to the tiger mitochondrial cytochrome b gene, successful amplification has been reliably achieved from blood, hair and bone as well as from a range of TCMs spiked with 0.5% tiger bone. Although capable of detecting fewer than 10 substrate molecules, the seven varieties of TCM pills and plasters tested showed no detectable trace of tiger DNA before spiking. Furthermore, sequencing several "tiger bone" fragments seized from TCM shops has shown that they actually originated from cattle and pigs. The potential effects of traditional bone preparation methods, evidence that much lower concentrations are used than alleged on TCM packaging, and substitution of bones from other species all suggest a low likelihood of detecting tiger DNA in patent medicines. Despite this, the basic methods have been thoroughly proven and can be readily applied to derivatives from other CITES protected species providing a rapid and highly sensitive forensic test for species of origin. Potential applications to the monitoring of wild populations are demonstrated by the successful identification of shed hairs and faecal samples.     

Evaluation of the modified zinc test and the acid phosphatase test as preliminary screening methods in sexual assault case material.

The modified zinc test and a commercially available acid phosphatase test were compared as to their screening parameters according to the microscopical finding of spermatozoa in cases of alleged sexual assault. The study involved 65 pieces of evidence material. It was found that the modified zinc test has a higher sensitivity and higher predictive values than the acid phosphatase test. However, when both tests are combined in parallel, the sensitivity and the negative predictive value could be raised to 99%. This finding suggests that a negative result obtained from the parallel combination of the modified zinc test and the acid phosphatase test predicts very well that no spermatozoa will be found at microscopical examination. Since the latter technique is the only one to give absolute proof of the seminal origin of stains or traces, the parallel combination of the zinc test and the acid phosphatase test might be useful in sorting out these cases or materials that deserve further investigation by more elaborate techniques.     

A new computer-assisted possibility for evaluating the evidence value of textile fiber traces

This paper deals with the possibility of coding synthetic textile fibers. Using a small data bank the efficiency of a computer aided data search is demonstrated. It is intended to build up a large collection of textile fibers and to determine at least approximately the frequency of a certain fiber type. If this can be achieved the forensic scientist who has to examine textile fibers in case work will be able for the first time to answer the question about the frequency of an incriminating fiber, a question which is often asked in court.