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.     

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.     

A new criminologic procedure: study of L-cystine-aminopeptidase activity for the detection of seminal stains

L-Cystine-aminopeptidase (CAP) enzyme cleaves L-cystine-di-beta-naphthylamide substrate to beta-naphthylamine. The final product of this process is a violet azostain. CAP enzyme determination was developed for criminological procedures. CAP shows almost 100 times greater activity in human semen than in other body fluids. Samples taken at different time intervals (1 week, 1-3-6 months, 1 year, and 5-10 years) were investigated; they were dried on cloth and filter paper and then stored at room temperature for various time periods. The enzyme was also shown to be specific in the comparative studies performed with other human secretions (nasal discharge, saliva, vaginal secretion, feces, urine, breast milk) and fruit juices (raspberry, strawberry, apple, pear, plum, tomato, etc.).     

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.     

Detection of amphetamine in bloodstains,semen, seminal stains,saliva, and saliva stains

Low nanogram quantities of amphetamine were detected in 100μl samples of dried bloodstains using radioimmunoassay. Saliva, saliva stains, semen, and seminal stains also contained measurable quantities of the drug.     

Effect of water immersion on seminal stains on cotton cloth

Reports on identification of seminal stains and spermatozoa on washed clothing are available. However, their detection on such clothing seems to depend on the washing material and the procedure adopted. It is reported here that prolonged immersion in water does not affect the detection of stains and spermatozoa.Results of experiments on water-immersed cotton clothing from 12 to 144 hours of water immersion are presented here. It is seen that intact human spermatozoa could be detected on such material even at 120 hours.     

Blind field test evaluation of Raman spectroscopy as a forensic tool

Analytical instrumentation for Raman spectroscopy has advanced rapidly in recent years to the point where commercial field-portable instruments are available. Raman analysis with portable instrumentation is a new capability that can provide emergency response teams with on-site evaluation of hazardous materials. Before Raman analysis is accepted and implemented in the field, realistic studies applied to unknown samples need to be performed to define the reliability of this technique. Studies described herein provide a rigorous blind field test that utilizes two instruments and two operators to analyze a matrix that consists of 58 unknown samples. Samples were searched against a custom hazardous materials reference library (Hazardous Material Response Unit (HMRU) Spectral Library Database). Experimental design included a number of intentionally difficult situations including binary solvent mixtures and a variety of compounds that yield medium-quality spectra that were not contained in the HMRU library. Results showed that over 97% of the samples were correctly identified with no occurrences of false positive identifications (compounds that were not in the library were never identified as library constituents). Statistical analysis indicated equivalent performance for both the operators and instruments. These results indicate a high level of performance that should extrapolate to actual field situations. Implementation of Raman techniques to emergency field situations should proceed with a corresponding level of confidence.     

The use of scanning electron microscopy in the examination of seminal stains

Samples of human seminal stains on fabrics, paper and wood were observed with a scanning electron microscope (S.E.M). It seems a reliable, rapid and simple technique for the routine examination of seminal stains.     

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.     

Development of a radial gel diffusion technique for the identification of urea in urine stains

A radial gel diffusion method utilizing urease and bromthymol blue has been developed for urine stain identification. Urea, present in urine in relatively high concentrations, can be detected from urine stain extracts. This technique provides both qualitative and quantitative results, and is sensitive enough to detect 0.078 micrograms/microliter of urea.     

Dual examinations for identification of urine as being of human origin and for DNA-typing from small stains of human urine

Concurrent methods for identification of urine as being of human origin, and for DNA-typing from small stains of human urine were examined. A urine stain was extracted with phosphate-buffered saline (PBS), and the extract was filtered using a Centricon-100 device. The filtrate was subjected to electrospray ionization liquid chromatography-mass spectrometry (ESI-LC-MS) for identification of human urine and a DNA-typing sample was obtained by dialfiltration of the residue using a DNA purification kit. After the purified residue was treated with an AmpflSTR Profiler PCR amplification kit, the DNA-types were analyzed by capillary electrophoresis using a Genetic Analyzer. It was possible to identify a urine stain as being of human origin, and complete DNA profiles could be successfully obtained from a urine stain which had been created by 50 microL of female urine. Serial analyses of urine stains found at a crime scene provide effective information for forensic investigation. This method is recommended for stain identification and for DNA-typing from a urine stain.     

DNA barcoding as a tool for species identification in three forensic wildlife cases in South Africa

Poaching of wildlife animals for subsistence and commercial purposes has lead to population declines in Africa. In forensic cases, a need exists to identify the species of origin of carcasses, meat or blood. In the study presented here, the mitochondrial COI gene was sequenced to determine the species of unknown samples in three suspect South African forensic wildlife cases. In two cases the unknown samples were identified as originating from domestic cattle (Bos taurus) and in the third case the sample was identified as common reedbuck (Redunca arundinum). This is the first report of the COI sequence of common reedbuck. The study highlights the need for accurate wildlife reference material from each country in order to convict wildlife cases.     

Applicability of two commercially available kits for forensic identification of saliva stains

The RSID-saliva test and the SALIgAE-saliva test are two recently developed forensic saliva detection kits. In this study, we compared the sensitivity and the specificity of the two test kits with the Phadebas amylase test by analyzing amylases from various sources including human, animals, plants, and micro-organism. The data demonstrate that the RSID-saliva test and the SALIgAE-saliva test offer higher sensitivity and specificity for the detection of saliva than the Phadebas amylase test. The detection limits of the RSID-saliva test, the SALIgAE-saliva test, and the Phadebas amylase test equate to 10, 4, and 1000 nL, respectively for human saliva. The RSID-saliva test and the SALIgAE-saliva test were further evaluated by analyzing semen, vaginal secretion, breast milk, blood, urine, sweat, and feces. The results of the two tests are in good agreement. The two tests reacted with urine, breast milk, and feces, but not with semen, vaginal secretion, blood, and sweat.     

The detection of protein p30 in seminal stains by means of thin-layer immunoassay

The detection of p30 by means of an indirect thin-layer immunoassay (TIA) is described. Extracts from 20 samples can be analyzed in approximately 2 h with a detection limit of approximately 50 ng. The p30 protein was detected in seminal stains which had been stored at room temperature for six months and at 130 degrees C for 4 h. Blood, saliva, urine, perspiration, and tears did not interfere with the method. The reliability of the method was demonstrated in a blind study.     

Vegetation dynamics as a tool for detecting clandestine graves

The burial of a body can affect plant communities through mechanical disturbance and nutrient balance alteration. We performed an experimental trial using five swine carcasses buried in an open site in Italy. Vegetation dynamics was monitored recording monthly every plant individual on a regular sampling grid during 1 year on the graves, on an empty control grave, and on an undisturbed plot. Plant species composition and cover were significantly different between the disturbed and the undisturbed plots. Disturbed plots showed the increase in ruderal species and the reduction in stress-tolerant ones. Graves and the control grave could not be distinguished from each other. Disturbance was the main factor affecting plant cover, while the presence of a buried body did not affect vegetation dynamics. However, disturbance could be easily detected; the functional approach seems promising for the identification of dynamic patterns to be used in different biogeographic and ecological contexts.     

A more sensitive modification of the zinc test for seminal traces suitable for stable test paper strips.

A more sensitive modification of the zinc test for semen has been developed, which can be used either as a solution or incorporated into test papers. The latter retain their sensitivity for at least 3 months.     

Determination of questionable suicide as a homicide by studies of criminal stains

In a woman found dead with cuts on both arms in a domestic sauna plastered with blood were assumed next to a bleed to death. The question self-infliction or by a third party of arm injuries could not be decided. By investigation of blood traces only could be clarified the cause of death. The husband had strangled his wife and inflicted several cuts on both arms with a razor blade to simulate suicide. Afterwards, he also inflicted several cuts on himself with a razor blade with the intention of suicide. He survived these injuries.     

A multi-enzyme electrophoretic system for the identification of seminal fluid from postmortem specimens

The screening of autopsy specimens, vaginal, buccal, and rectal swabs, for the presence of seminal fluid in rape homicide investigations utilizing classical techniques can lead to erroneous results. In the absence of spermatozoa, techniques are needed which can help to identify seminal fluid. This report illustrates the use of a multi-enzyme electrophoretic approach identifying seminal acid phosphatase (SAP) and lactic acid dehydrogenase (LDH-X) as an initial screening procedure. Subsequent analyses for the presence of acid and alkaline phosphatase (semiquantitative) yield information which can help identify false-positive SAP's. Additionally, salivary amylase can be tentatively identified using the same multi-enzyme procedure which informs the investigator of possible salivary contamination of the sample and possible erroneous PGM results. Statistics utilizing the multi-enzyme approach in case work are also presented.     

新精神活性物质检验鉴定面临的挑战和对策

新精神活性物质更新快,种类繁多,缺乏国际条约的监管,列入联合国管控目录困难,加之一些国家和国际社会对大麻等毒品管控降低,给我国在新精神活性物质类毒品的监管带来困难.具有成瘾性和社会危害性的新精神活性物质才能成为列管对象,毒物分析技术人员在列管程序中扮演极为重要的角色.我国对新精神活性物质的监管法规规定了相关列管程序,毒...