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1.
Forensic Sci Int Genet ; 55: 102598, 2021 11.
Artigo em Inglês | MEDLINE | ID: mdl-34619439

RESUMO

Copper is a metal that is commonly found in many evidence types, such as weapons, and household items, that are often retrieved from crime scenes. We used copper and brass sheets, cartridge cases, and metal décor items as substrates for deposition of blood to study inhibition induced by metals. Another objective was to compare the efficiency of STR profiling following extraction, quantification, amplification, and capillary electrophoresis with a direct amplification method which only requires amplification and capillary electrophoresis. Samples that were designated for extraction, were collected, extracted, and purified using the Qiagen EZ1 DNA Investigator® Kit. Direct amplification was performed using Copan microFLOQ® Direct Swabs to collect minute amount of blood. Complete STR profiles were obtained from 54% of the extracted samples and from 88% of directly amplified samples. Substrate type and amplification method (two-way ANOVA, F(5, 131) = 3.59, p = 4.50 × 10-3) impacted profile completeness but collection time did not (one-way ANOVA, F(1, 131) = 0.017, p = 0.90). Composition of the substrates was determined with scanning electron microscopy (SEM), and inhibition caused by copper was evaluated for each substrate. When substrate composition was analyzed in combination with amplification method, a substrate's copper percent was not associated with increased allelic dropout (one-way ANOVA, F(1, 176) = 0.70, p = 0.40) but amplification alone was statistically significant (one-way ANOVA, F(1, 176) = 40.64, p = 1.56 × 10-9). Using the Copan microFLOQ® Direct Swabs, inhibition induced by metal observed was not as pronounced. In addition, less variability in profile completeness was detected, profiles were generated within a very short period, and only minute amount of bloodstain was needed, allowing for additional analysis of the same samples. Our results directly quantify the effect of copper composition on DNA profiling and suggest that while copper percentage is an observational contributor to allele dropout it is not wholly responsible for these events.


Assuntos
Manchas de Sangue , Repetições de Microssatélites , DNA/genética , Impressões Digitais de DNA , Humanos , Reação em Cadeia da Polimerase
2.
Molecules ; 26(20)2021 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-34684853

RESUMO

Bloodstains found at crime scenes represent a crucial source of information for investigative purposes. However, in forensic practice, no technique is currently used to estimate the time from deposition of bloodstains. This preliminary study focuses on the age estimation of bloodstains by exploiting the color variations over time due to the oxidation of the blood. For this purpose, we used a colorimetric methodology in order to easily obtain objective, univocal and reproducible results. We developed two bloodstain age prediction algorithms: a short-term and a long-term useful model for the first 24h and 60 days, respectively. Both models showed high levels of classification accuracy, particularly for the long-term model. Although a small-scale study, these results improve the potential application of colorimetric analysis in the time-line reconstruction of violent criminal events.


Assuntos
Colorimetria/métodos , Medicina Legal/métodos , Adulto , Algoritmos , Manchas de Sangue , Feminino , Humanos , Masculino , Projetos Piloto
3.
Sud Med Ekspert ; 64(5): 53-56, 2021.
Artigo em Russo | MEDLINE | ID: mdl-34644035

RESUMO

Objective - to present a comparative analysis of the specialized literature on the possibility of using a luminol solution to detect blood traces when examining the scene of an incident. The use of this sample at the incident scene is only preliminary, since its high sensitivity connected with nonspecific properties. Information about the possibility of identifying the species, group and DNA belonging of blood traces after their treatment with a luminol solution is contradictory, therefore, its use at the scene should be careful with the preservation of intact (not treated with luminol) blood traces available for their study by traditional forensic biological methods. The possibility of laboratory determination of the properties of blood after processing its traces with a luminol solution can be proved by a special scientific and experimental forensic biological work.


Assuntos
Manchas de Sangue , Luminol , Medicina Legal
4.
J Forensic Sci ; 66(6): 2424-2437, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34363402

RESUMO

One of the first challenges that crime scene examiners have is determining if a substance is blood before performing analysis. Conventional methods of detecting blood involve the use of chemicals and different wavelengths of light in tandem with digital photography. However, these methods are destructive or provide false positives. Visible wavelength hyperspectral imaging (HSI) is a noncontact blood detection method that has been proven to provide accurate and reliable results. A novel application of this technique has been used for the detection and positive identification of bloodstained footwear marks, of different dilutions ranging from undiluted to 1:50 with distilled water, and on a range of substrates, and colors. Comparisons between HSI and conventional digital photography were made using a grading scale and analyzed using Mann-Whitney U-tests. The HSI technique was able to detect a statistically significant greater amount of tread detail on white tiles, laminate, carpet, and blue tiles compared with the digital photography technique, which was only superior on black tiles. Critically, the HSI technique was also able to determine that the footwear marks were made in blood. These results show that HSI will be useful in forensic investigations, where it is known that the perpetrator has walked through the victim's blood and left a trail of footwear marks at the crime scene. Even if the perpetrator had time to clean up afterward resulting in diluted stains, HSI would still be able to detect bloodstained footwear marks with a greater amount of detail compared with digital photography.


Assuntos
Manchas de Sangue , Imageamento Hiperespectral , Processamento de Imagem Assistida por Computador , Fotografação , Sapatos , Ciências Forenses/métodos , Humanos
5.
Forensic Sci Int ; 325: 110891, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34247141

RESUMO

This study examines the spectral characteristics of blood after being exposed to intense heat within a structural fire. Fire and intense heat have previously been understood to destroy or chemically change bloodstain evidence so that traditional forensic science recovery techniques are rendered ineffectual. Understanding the effects of the denaturation process and physical changes that occur to blood when exposed to heat may develop innovative forensic investigation methods, including the use of reflected infrared photography to enhance the recording of bloodstains. This research revealed that the denaturation of blood, specifically changes to the haemoglobin state from oxyhaemoglobin to methaemoglobin, resulted in the heat affected blood having a more optimal spectral target range within the infrared region when exposed to heat> 200 °C. It was observed both qualitatively and quantitatively using spectrophotometry, that there is a relationship between the appearance, viscosity and infrared absorption properties of blood when exposed to different temperatures as experienced in fire. This result indicated the increased potential for reflected infrared photography to be utilised as an effective tool for crime scene evidence recovery of bloodstains from arson scenes involving fire.


Assuntos
Análise Química do Sangue , Manchas de Sangue , Incêndios , Viscosidade Sanguínea , Cor , Piromania , Humanos , Metemoglobina/análise , Oxiemoglobinas/análise , Espectrofotometria
6.
Forensic Sci Int ; 325: 110876, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34216943

RESUMO

The age estimation of blood traces provides important leads for the chronological assessment of criminal events and their reconstruction. To determine bloodstain age, experimental comparative data from a laboratory environment are used. Under these conditions the utilization of anticoagulants such as EDTA helps to suppress the blood clotting mechanism to allow the examination over a longer time period. This unnatural prevention of blood coagulation is highly questionable when estimating bloodstain age, since the blood's physical and chemical properties are altered. For this reason, the authors determined actual influence of EDTA on blood spectra over time in order to formulate a statement as to whether this effect can be measured. Human and porcine blood samples were aged under controlled conditions. The resulting UV/VIS spectra were separated into their individual components using signal separation techniques, allowing the changes in the ratios of the individual hemoglobin derivatives to be observed over time. The results show a significant influence of EDTA on the conversion of oxyhemoglobin to methemoglobin and a minor influence on the conversion of methemoglobin to hemichrome within the relevant time range of 5-100 h. The use of EDTA thus slows down the aging process of blood spots. To illustrate the great influence of EDTA, spectra of untreated pig blood samples were included as comparison data. These show that the difference between EDTA-treated and untreated blood samples is as great as the difference between human blood and pig blood. As a consequence of our findings experimental comparative data for the age estimation of bloodstains should never result from EDTA-treated blood.


Assuntos
Anticoagulantes/farmacologia , Manchas de Sangue , Ácido Edético/farmacologia , Animais , Feminino , Medicina Legal , Hemeproteínas/análise , Humanos , Masculino , Metemoglobina/análise , Oxiemoglobinas/análise , Espectrofotometria Ultravioleta , Suínos , Fatores de Tempo
7.
J Photochem Photobiol B ; 221: 112251, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34229147

RESUMO

Blood is one of the most common body fluids discovered at crime scenes involving violent actions. It is one of the most important types of forensic evidence since it allows for the identification of the individual providing that there is a match with a known DNA profile. Determining the time since deposition (TSD) can assist investigators in establishing when the crime occurred or if a bloodstain present is actually related to the investigated event. To develop a forensically sound method for determining the TSD of a bloodstain, it is necessary to understand the underlying biochemical mechanisms occurring during aging. As biochemical processes occurring in blood are necessary for the continued survival of living organisms, they are important subjects of human biology and biomedicine and are well understood. However, the biochemistry of bloodstain aging ex vivo is primarily of interest to forensic scientists and has not yet been thoroughly researched. This preliminary study utilizes steady-state fluorescence spectroscopy to probe the changes in fluorescence properties of peripheral and menstrual blood up to 24-h post deposition. Peripheral and menstrual blood exhibited similar kinetic changes over time, assigned to the presence of the fluorophores: tryptophan, nicotinamide adenine dinucleotide (NADH), and flavins in both biological fluids. The biochemical mechanism of blood aging ex vivo is discussed.


Assuntos
Manchas de Sangue , Espectrometria de Fluorescência/métodos , Análise Química do Sangue , Feminino , Flavinas/química , Humanos , Masculino , NAD/química , Oxirredução , Fatores de Tempo , Triptofano/química
8.
Forensic Sci Int ; 325: 110856, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34116402

RESUMO

Although the analysis of bloodstain pattern evidence left at crime scenes relies on the expert opinions of bloodstain pattern analysts, the accuracy and reproducibility of these conclusions have never been rigorously evaluated at a large scale. We investigated conclusions made by 75 practicing bloodstain pattern analysts on 192 bloodstain patterns selected to be broadly representative of operational casework, resulting in 33,005 responses to prompts and 1760 short text responses. Our results show that conclusions were often erroneous and often contradicted other analysts. On samples with known causes, 11.2% of responses were erroneous. The results show limited reproducibility of conclusions: 7.8% of responses contradicted other analysts. The disagreements with respect to the meaning and usage of BPA terminology and classifications suggest a need for improved standards. Both semantic differences and contradictory interpretations contributed to errors and disagreements, which could have serious implications if they occurred in casework.


Assuntos
Manchas de Sangue , Prova Pericial , Variações Dependentes do Observador , Medicina Legal , Humanos , Reprodutibilidade dos Testes
9.
ACS Appl Mater Interfaces ; 13(23): 27419-27429, 2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34080426

RESUMO

Both latent sebaceous and blood fingerprints may provide valuable information for forensic investigation. To detect both types of fingerprints with no need to predistinguish them, a new adaptive developing strategy was proposed. A cationic conjugated polymer with poly[p-(phenylene ethylene)-alt-(thienylene ethynylene)] backbone (PPETE-NMe3+) was synthesized, which was dissolved in N,N-dimethylformamide (DMF) to form the developing solution. Fingerprints were developed by a simple dropping and incubating process without any pre-/post-treatments. Fluorescent photographs of the developed fingerprints on various substrates demonstrated that this developing strategy was effective for both types of fingerprints on nonporous substrates. Gray value analysis further confirmed the enhancement of the legibility of the fingerprint images. The preliminary mechanism exploration suggested that certain weak interactions, such as hydrophobic interaction and electrostatic interaction, may synergistically contribute to the interaction between the polymer and fingerprint components. The molecular design of the polymer combined with an appropriate solvent endowed the developing system the adaptiveness toward different types of fingerprints. This adaptive developing strategy made the fingerprint-developing process more efficient and may be further extended to more practical application scenes.


Assuntos
Manchas de Sangue , Cátions/química , Corantes/química , Dermatoglifia , Fluorescência , Polímeros/química , Glândulas Sebáceas/química , Medicina Legal , Humanos , Interações Hidrofóbicas e Hidrofílicas , Propriedades de Superfície
10.
Sud Med Ekspert ; 64(3): 64-68, 2021.
Artigo em Russo | MEDLINE | ID: mdl-34013700

RESUMO

The historical analysis and the results of research activities of the Department of Forensic Medicine of the Sechenov University on the study of blood stains as important material evidence in forensic medicine and forensic science are presented. The personal contribution to the solution of this problem of outstanding forensic doctors whose life and work was associated with the department was noted.


Assuntos
Manchas de Sangue , Medicina Legal/educação , Ciências Forenses , Humanos , Universidades
11.
Sensors (Basel) ; 21(9)2021 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-33925330

RESUMO

Blood is key evidence to reconstruct crime scenes in forensic sciences. Blood identification can help to confirm a suspect, and for that reason, several chemical methods are used to reconstruct the crime scene however, these methods can affect subsequent DNA analysis. Therefore, this study presents a non-destructive method for bloodstain identification using Hyperspectral Imaging (HSI, 397-1000 nm range). The proposed method is based on the visualization of heme-components bands in the 500-700 nm spectral range. For experimental and validation purposes, a total of 225 blood (different donors) and non-blood (protein-based ketchup, rust acrylic paint, red acrylic paint, brown acrylic paint, red nail polish, rust nail polish, fake blood, and red ink) samples (HSI cubes, each cube is of size 1000 × 512 × 224, in which 1000 × 512 are the spatial dimensions and 224 spectral bands) were deposited on three substrates (white cotton fabric, white tile, and PVC wall sheet). The samples are imaged for up to three days to include aging. Savitzky Golay filtering has been used to highlight the subtle bands of all samples, particularly the aged ones. Based on the derivative spectrum, important spectral bands were selected to train five different classifiers (SVM, ANN, KNN, Random Forest, and Decision Tree). The comparative analysis reveals that the proposed method outperformed several state-of-the-art methods.


Assuntos
Manchas de Sangue , Imageamento Hiperespectral , Ciências Forenses , Têxteis
12.
Forensic Sci Int ; 323: 110774, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-33930825

RESUMO

Matrix Assisted Laser Desorption Ionization Mass Spectrometry Profiling and Imaging (MALDI MSP and MALDI MSI), in combination with bottom up proteomics, have proven to successfully detect and map blood-derived peptide signatures in blood fingermarks, with high specificity and compatibility with a number of blood enhancement techniques (BET). In the present study, the application of MALDI MSP and MSI to blood marks has been investigated further. In particular, the MALDI based detection and visualisation of blood has been explored in tandem with DNA typing. This investigation has been undertaken in a scenario simulating blood fingermarks on painted walls. In the present study, two sets of marks were analysed with each set comprising of a depletion series of four marks deposited on a surface treated to simulate painted walls: Set I - developed with Ninhydrin (NIN) and Set II- developed with Acid Black-1 (AB-1). For both sets, the application of MALDI MSP was successful in detecting haem and human specific haemoglobin peptide markers. MALDI MSI also provided molecular images by visualising haem on the ridge pattern enhanced by BET. The feasibility of successful and subsequent DNA profiling from the recovered fingermarks was also assessed for marks that had undergone enzymatic in situ digestion and MALDI MSI; it was observed that in 73% of the samples analysed, a DNA profile suitable for comparison was obtained. Based on these results, a possible operational workflow has been proposed incorporating the use of a MALDI MS based approach as a confirmatory test for human blood enabling subsequent DNA typing.


Assuntos
Manchas de Sangue , Impressões Digitais de DNA/métodos , DNA/análise , Dermatoglifia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Corantes , Humanos , Indicadores e Reagentes , Ninidrina
13.
Med Sci Law ; 61(4): 292-301, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-33926284

RESUMO

The most important task in a criminal investigation is to detect and identify the recovered biological stains beyond reasonable scientific doubt and preserve the sample for further DNA analysis. In the light of this fact, many presumptive and confirmatory tests are routinely employed in the forensic laboratories to determine the type of body fluid. However, the currently used techniques are specific to one type of body fluid and hence it cannot be utilized to differentiate multiple body fluids. Moreover, these tests consume the samples in due process, and thus it becomes a great limitation especially considering the fact that samples are recovered in minute quantity in forensic cases. Therefore, such limitations necessitate the use of non-destructive techniques that can be applied simultaneously to all types of bodily fluids and allow sample preservation for further analysis. In the current work, attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy has been used to circumvent the aforementioned limitations. The important factors which could influence the detection of blood such as the effect of substrates, washing/chemical treatment, ageing, and dilution limits on the analysis of blood have been analysed. In addition, blood discrimination from non-blood substance (biological and non-biological in nature) has also been studied. Chemometric technique that is PCA-LDA has been used to discriminate blood from other body fluids and it resulted in 100% accurate classification. Furthermore, blood and non-blood substances including fake blood have also been classified into separate clusters with a 100% accuracy, sensitivity, and specificity. All-inclusive, this preliminary study substantiates the potential application of ATR-FTIR spectroscopy for the non-destructive identification of blood traces in simulated forensic casework conditions with 0% rate of false classification.


Assuntos
Manchas de Sangue , Líquidos Corporais , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Adulto , Análise Discriminante , Feminino , Humanos , Masculino , Análise de Componente Principal , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
14.
Sci Rep ; 11(1): 8029, 2021 04 13.
Artigo em Inglês | MEDLINE | ID: mdl-33850175

RESUMO

When detecting DNA profiles from forensic materials, it is pivotal to know the extent of degradation and which DNA marker can be genotyped. Ultraviolet (UV) is one of the common external factors that causes DNA damage, through which, an attempt to reveal cardinal genetic information can be made. In this study, after irradiation with three different UV wavelengths, UV-damaged DNA in the bloodstains was analyzed with long and short TaqMan assays using real-time PCR. In addition, both short tandem repeat (STR) profiles and single nucleotide polymorphisms (SNPs) from the damaged DNA at different stages of UV exposure were also assessed. With increasing in UV irradiation cycles, there was a delay of the amplification curves accompanied with a decrease in the DNA amounts collected. Despite the amplification of STR genotype was not altered after 75 cycles of UVC irradiation, all 12 SNP loci could still be detected. Furthermore, a short-assay line was detected in the absence of an amplification of the evaluation curve. The results indicate that, although the DNA template might not be useful and suitable for analysis of STR profile, this approach is of some values in detecting SNPs.


Assuntos
Manchas de Sangue , Reação em Cadeia da Polimerase , Polimorfismo de Nucleotídeo Único , Marcadores Genéticos , Humanos
15.
Fa Yi Xue Za Zhi ; 37(1): 65-68, 2021 Feb.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-33780187

RESUMO

Abstract: Objective To evaluate the effects of DNA examination of trace bloodstain samples from the scene collected with Trace Biological Evidence Collection kit. Methods Venous blood was made into bloodstains on the ground. The trace bloodstain samples were collected with Trace Biological Evidence Collection kit and common methods, respectively. DNA examination of trace bloodstain samples (50 from each group) was conducted on the constant temperature shaker for 2, 24, 48, 72, and 96 h, respectively, and the examination results of every group were compared. Results When the trace bloodstain samples were placed on the constant temperature shaker for 24, 48, 72, and 96 h, the DNA detection rates in the group which used Trace Biological Evidence Collection kit (100.00%, 100.00%, 100.00%, 96.00%) were significantly higher than those in the group using common methods (62.00%, 26.00%, 10.00%, 0), the differences had statistical significance (P<0.05). When the trace bloodstain samples were placed on the constant temperature shaker for 2 h, the differences of DNA detection rates between the two groups had no statistical significance ( P>0.05). Conclusion The Trace Biological Evidence Collection kit can effectively improve DNA detection rate and extend detection time limit for trace bloodstain samples from the scene that have been stored for a relatively long time.


Assuntos
Manchas de Sangue , DNA , Medicina Legal , Temperatura
16.
ACS Appl Mater Interfaces ; 13(13): 15621-15632, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33780233

RESUMO

Latent blood fingerprints (LBFPs) can provide critical information of foul play and help identify the suspects at violent crime scenes. The current methods for LBFP visualization are still not satisfactory because of the low sensitivity or complicated protocol. This study demonstrates a simple and effective LBFP visualization strategy by integrating a new amphiphilic fluorescent amino-functionalized conjugated polymer with the cotton-pad developing protocol. LBFPs on various substrates are visualized by simply covering them with the polymer solution-soaked cotton pads. The images display clear fingerprint patterns, ridge details, and sweat pores, even on very challenging substrates such as painted wood and multicolored can. The gray value analysis confirms semiquantitatively the enhancement of the contrast between ridges and furrows. Even LBFPs with various contaminations or aged for more than 600 days are effectively developed and visualized. The developed fingerprint images show superior stability over long storage time and against solvent washing. Moreover, the polymer causes no degradation of DNAs in the blood, suggesting the possibility of further DNA profiling and identification after development. The mechanistic investigation suggests that the formation of positive or inverted images can be attributed to the synergistic effects from the affinity between polymer and blood, and the affinity betwen polymer and substrate, as well as the slight quenching of polymer fluorescence by blood. Furthermore, the covalent bonding between the protonated primary amino group and proteins in blood endows the stability of the developed fingerprints. The result rationalizes the molecular design of the fluorescent polymer and sheds new light on the future strategies to effective LBFP visualization in practical applications.


Assuntos
Proteínas Sanguíneas/análise , Dermatoglifia , Corantes Fluorescentes/química , Manchas de Sangue , Ciências Forenses , Humanos , Imagem Óptica/métodos , Polímeros/química
17.
Forensic Sci Int ; 320: 110701, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33581656

RESUMO

The sensitivity of imaging spectroscopy to haemoglobin derivatives makes it a promising tool for detecting blood. However, due to complexity and high dimensionality of hyperspectral images, the development of hyperspectral blood detection algorithms is challenging. To facilitate their development, we present a new hyperspectral blood detection dataset. This dataset, published under an open access license, consists of multiple detection scenarios with varying levels of complexity. It allows to test the performance of Machine Learning methods in relation to different acquisition environments, types of background, age of blood and presence of other blood-like substances. We have explored the dataset with blood detection experiments, for which we have used a hyperspectral target detection algorithm based on the well-known Matched Filter detector. Our results and their discussion highlight the challenges of blood detection in hyperspectral data and form a reference for further works.


Assuntos
Manchas de Sangue , Conjuntos de Dados como Assunto , Ciências Forenses/métodos , Imageamento Hiperespectral , Algoritmos , Humanos , Funções Verossimilhança , Aprendizado de Máquina
18.
Anal Bioanal Chem ; 413(9): 2513-2522, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33580831

RESUMO

Body fluid traces can provide highly valuable clues in forensic investigations. In particular, bloodstains are a common occurrence in criminal investigation, and the discrimination of menstrual and peripheral blood is a crucial step for casework involving rape and sexual assault. Most of the current protocols require the detection of characteristic menstrual blood components using sophisticated procedures that need to be performed in a laboratory. The present study uses attenuated total reflection Fourier transform-infrared (ATR FT-IR) spectroscopy as a nondestructive technique for discriminating menstrual and peripheral blood traces. This method incorporates statistical analysis and was evaluated by internal and external validation testing. A partial least squares discriminant analysis (PLSDA) classification model was created for differentiating the two types of blood in a binary manner. Excellent separation between menstrual and peripheral blood samples was achieved during internal validation. External validation resulted in 100% accuracy for predicting a sample as peripheral or menstrual blood. This study demonstrates that ATR FT-IR spectroscopy combined with chemometrics is a reliable approach for rapid and nondestructive discrimination of menstrual and peripheral bloodstains. It offers a significant advantage to forensic science due to the availability of portable instruments and the potential for bloodstain analysis at a crime scene. Graphical abstract.


Assuntos
Análise Química do Sangue , Manchas de Sangue , Menstruação/sangue , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Líquidos Corporais/química , Análise Discriminante , Feminino , Medicina Legal , Humanos , Análise dos Mínimos Quadrados , Delitos Sexuais
19.
Forensic Sci Int Genet ; 51: 102456, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33444974

RESUMO

The relationship between RNA degradation and the age of a bloodstain has been suggested by the work of several investigators. A prior study from this laboratory described a qPCR assay that was effective at estimating the age of bloodstains stored in an environmentally controlled laboratory for periods of up to one year. In this study, the effect of the environmental conditions on the rate of RNA degradation during storage was analyzed. Bloodstains were prepared on stain cards and stored in one of 9 different environments for periods of up to 24 weeks. At selected times during the storage term, RNA was extracted, reverse transcribed, and the integrity of select transcripts analyzed. Three temperatures (37 °C, 20 °C, and 4 °C) and three relative humidities (rH) (75 %, 35 %, and 10 %) were combined pairwise. The rate of RNA degradation was found to increase 5-10 fold in stains stored at 37 °C versus those stored at 20 °C. The rate of RNA degradation was faster for stains stored at 20 °C compared to 4 °C but differed only 2-4 fold. Multivariate regression analysis suggests elevations in temperature or rH will accelerate RNA degradation and will do so to a similar extent. It is clear from the data that the integrity of the transcriptome in dried bloodstains is better preserved in a cold and dry environment. Investigations are ongoing to develop an approach for the estimation of sample age that incorporates the environmental conditions of a crime scene into the age estimate.


Assuntos
Manchas de Sangue , Estabilidade de RNA , Manejo de Espécimes/métodos , Feminino , Genética Forense , Humanos , Umidade , Masculino , Temperatura
20.
Arch. bronconeumol. (Ed. impr.) ; 57(1): 42-50, ene. 2021. graf, mapas, tab
Artigo em Inglês | IBECS | ID: ibc-200200

RESUMO

INTRODUCTION: The objective of this analysis was the evaluation of a new national circuit used for diagnosing alpha1 antitrypsin deficiency (AATD) based on multiplex technology using online registration and mail posted samples from dried blood spots (DBS) and buccal swabs. METHODS: This is an observational, ongoing study conducted in Spain since March 2018. Samples are coded on a web platform and sent by postal mail to the central laboratory. Allele-specific genotyping for the 14 most common mutations was done with the Luminex 200 Instrument System. Gene sequencing was done if none of the mutations were found and the AAT serum level was < 60 mg/dl, or by request from the clinician in charge. RESULTS: At the time of the present report, 5803 (92.9%) samples were processed, 4984 (85.9%) from buccal swab and 819 (14.1%) from DBS. The prevalence of the frequent allele combinations were: MS 19.0%, MZ 14.4%, SS 2.9%, SZ 3.7%, and ZZ: 1.4%. Globally, Z carriers represented 20.0% and S carriers 26.6% of this population, with differences seen between regions. 209 (3.6%) were identified carrying rare alleles, 12 (0.2%) carrying null alleles and 14 (0.3%) new mutations were described. Respiratory diseases other than COPD, including poorly controlled asthma or bronchiectasis, also presented AATD mutations. CONCLUSIONS: The availability of a diagnostic system based on the simultaneous testing of 14 genetic variants from buccal swabs or DBS sent by postal mail and with web registration has proven to be useful, and the system can improve the timely diagnosis of AATD


INTRODUCCIÓN: El objetivo de este análisis fue la evaluación de un nuevo circuito nacional utilizado para diagnosticar la deficiencia de alfa-1 antitripsina (DAAT) basado en tecnología multiplex con muestras de manchas de sangre seca (DBS, por sus siglas en inglés) y frotis bucales enviados por correo postal tras un registro previo en línea. MÉTODOS: Este es un estudio observacional en curso que se está llevando a cabo en España desde marzo de 2018. Las muestras se codifican en una plataforma web y se envían por correo postal al laboratorio central. El genotipado de un alelo específico buscando las 14 mutaciones más comunes se realizó con el sistema Luminex(R) 200. Se realizó secuenciación génica si no se encontraba ninguna de las mutaciones y el nivel sérico de AAT era < 60mg/dl, o por solicitud del médico responsable. RESULTADOS: En el momento del presente informe se habían procesado 5.803 (92,9%) muestras, 4.984 (85,9%) de frotis bucal y 819 (14,1%) de DBS. La prevalencia de las combinaciones frecuentes de alelos fue: MS 19,0%, MZ 14,4%, SS 2,9%, SZ 3,7% y ZZ 1,4%. Globalmente, los portadores de Z representaron el 20,0% y los portadores de S el 26,6% de esta población, observándose diferencias entre las regiones. Se identificaron 209 (3,6%) portadores de alelos raros, 12 (0,2%) portadores de alelos nulos y se describieron 14 (0,3%) nuevas mutaciones. Otras enfermedades respiratorias que no eran EPOC, incluyendo el asma mal controlado o las bronquiectasias, también presentaron mutaciones DAAT. CONCLUSIONES: La disponibilidad de un sistema de diagnóstico con registro web basado en el análisis simultáneo de 14 variantes genéticas de frotis bucales o DBS enviados por correo postal ha demostrado ser útil, y el sistema puede mejorar el diagnóstico temprano de DAAT


Assuntos
Humanos , Deficiência de alfa 1-Antitripsina/sangue , Deficiência de alfa 1-Antitripsina/diagnóstico , Reação em Cadeia da Polimerase Multiplex/métodos , Manchas de Sangue , Doença Pulmonar Obstrutiva Crônica/epidemiologia , alfa 1-Antitripsina/administração & dosagem , Técnicas de Genotipagem , Testes Genéticos , Doença Pulmonar Obstrutiva Crônica/genética , Frequência do Gene/genética
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