Forensic determination of pregnancy hormones in human bloodstains.

When different bloodstains are encountered at the scene of crime, it is possible to discriminate those from a pregnant woman from others. Human chorionic gonadotrophin, human placental lactogen, total oestriol and progesterone in the stains may be determined with radioimmunoassay techniques using commercial kits. Only 1 cm2 of bloodstain is needed for the determination of all four parameters, which gives information about the state of pregnancy. More than 100 stains of blood from women in all stages of pregnancy, normal menstruating women, menopausal and post-menopausal women and male subjects, and of menstrual blood were analysed. Bloodstains from pregnant women were easy to evaluate with the four determinations, only very early pregnancies being undetected. Stains from non-pregnant women were negative or below the cut-off level. Two case examples are also described.     

Detection of low levels of flunitrazepam and its metabolites in blood and bloodstains.

Detection of low levels of flunitrazepam and its metabolites was developed using solid-phase extraction to isolate the drugs from whole liquid blood and dried bloodstains, with subsequent derivatization with pentafluoropropionic anhydride (PFPA) followed by N-(tert-butyldimethyl-silyl)-N-methyl-trifluoroacetamide (MTBSTFA) with 1% TBDMSCI. Analysis was confirmed by gas chromatography/mass spectroscopy using select ion monitoring (sim) in electron impact mode. The limit of detection of this procedure using 1 ml of blood was determined to be 0.1 microgram/dl.     

血痕特异性mRNA标记研究

血痕是案发现场尤其是命案中比较常见的生物物证,而血痕的正确组织来源推断是当前鉴定工作中急需解决的问题。随着法医物证学的不断发展,以mRNA(messenger RNA)为基础的体液斑迹组织来源鉴定技术作为一种不同于传统血痕免疫学检测的新型方法,已经越加显示其独特的优越性。在该技术的基础上,实现共同提取生物物证的RNA与DNA的目标,建立体液斑迹鉴定与DNA分型兼容的方法,有利于现场重建,提高生物物证的证据效力,完善证据链。本研究建立了一个包括血痕总RNA提取、逆转录、荧光特异引物扩增、遗传分析仪电泳检测分析等步骤的血痕来源推断技术平台。实验共采集制备了40份的中国人群(女性)外周血、16份月经血样本,筛选了5个外周血标记:HBA、HBB、GYPA、SPTB、ALAS2,2个月经血标记:MMP7、MMP11,构建了一个囊括外周血、月经血特异标记的荧光复合扩增体系。结果显示mRNA技术为基础的鉴定血痕来源的方法是可行的,并且建立了血痕RNA检验的遗传分析仪结果判读方法。     

Sensitive fluorometric detection of heat-stable alkaline phosphatase from bloodstains for the forensic diagnosis of pregnancy

Sensitive and simple procedures are established for the forensic pregnancy test from bloodstains. This paper describes new techniques based on heat stability of placental alkaline phosphatase. In this study the total and heat-stable alkaline phosphatase activities were determined using 4-methylumbelliferyl-phosphate as substrate. The ratio of heatstable alkaline phosphatase to total alkaline phosphatase was calculated. A more simple screening test which was visible by exposure to UV light is described. These may be helpful in the diagnosis of pregnancy from only a slight bloodstain.     

Determination of the age of bloodstains using immunoelectrophoresis.

The technique of immunoelectrophoresis was used to determine the age of bloodstains. The immunoelectrophoretic patterns (IEP) of bloodstains ranging from 15 days to one year old were obtained by the use of high titer anti-whole human serum. The IEPs revealed gradual disappearance of beta-globulins and gamma-globulin with increase in the age of bloodstains. A comparative study of the IEP of normal human serum with those of the experimental bloodstains showed the absence of some of the corresponding proteins. The absence of a particular serum protein in the IEP of a given bloodstain will indicate the age of that bloodstain.     

SEM analysis of red blood cells in aged human bloodstains.

Mammal red blood cells (RBC) in bloodstains have been previously detected by light microscopy on stone tools from as early as 100,000 +/- 25,000 years ago. In order to evaluate the degree of morphological preservation of erythrocytes in bloodstains, an accidental human blood smear on white chert and several experimental bloodstains on hard substrates (the same stone-white chert; another type of stone-graywacke; a non-stone support-stainless steel), were stored in a room, in non-sterile and fluctuating conditions, for lengths of time ranging from 3 to 18 months. Afterwards, the specimens were coated with gold and examined by a Cambridge Stereoscan 120 scanning electron microscope. Results revealed a high preservation of RBC integrity, with the maintenance of several discocytary shapes, a low tendency to echinocytosis and a frequent appearance of a moon-like erythrocytary shape in the thinner areas of the bloodstains.     

An improved method for subtyping Pi in old bloodstains.

Immunofixation procedures were used for detecting alpha-1 antitrypsin protease inhibitor (Pi) phenotypes in bloodstains. Neuraminidase elution of bloodstains, together with isoelectric focusing, immunofixation, and silver staining techniques, makes possible Pi subtyping in old bloodstains. No extra bands appear when the storage time is no longer than three months.     

Transferrin subtyping of bloodstains and semen using isoelectric focusing and immunoblotting.

Transferrin (TF) subtyping was carried out on bloodstains that had been made on cotton sheeting and stored under a variety of conditions ranging from -20 degrees C to +37 degrees C. The time limit of detection was longer than 54 weeks after dry storage under each condition. Moreover the correlation between isoprotein types of the TF in blood and semen samples from the same individual was determined in 103 men. All three TF common types and two rare types in all semen samples correlated with the type found in the corresponding blood sample. A combination of isoelectric focusing separation and immuno-enzyme-linked detection may prove to be very useful for forensic TF subtyping.     

Human chorionic gonadotropin detection by means of enzyme immunoassay: a useful method in forensic pregnancy diagnosis in bloodstains

This paper reports on human chorionic gonadotropin (HCG) detection in bloodstains using a commercial kit based on enzyme immunoassay. The specificity and sensitivity of the method is tested, as well as HCG stability over time in the samples. Detection of this hormone in bloodstains is of special interest for pregnancy diagnosis in forensic science applications. The experimental series comprises 60 bloodstains prepared in our laboratory and obtained from blood samples taken from 30 pregnant women and 30 healthy, nonpregnant individuals. The bloodstains were studied at different stages of aging over a 6-month period, each sample being stored at 2 different temperatures throughout the process. The experimental evidence proves HCG to be a useful and stable diagnostic indicator of pregnancy in bloodstains. In addition, the technique used is fast, as well as highly sensitive and specific.     

Effects of luminol on the subsequent analysis of bloodstains.

The effects of luminol upon additional presumptive chemical tests, subsequent confirmatory blood tests, species determination by immunoelectrophoresis, ABO typing by absorption elution, and genetic marker analysis by multienzyme system electrophoresis were examined. Results indicate that luminol does not affect additional presumptive chemical tests, confirmatory tests, species determination, or ABO typing, but does affect certain genetic marker systems.     

Phosphoglucomutase (PGM) grouping of bloodstains on silver.

This paper describes a case involving alteration of phosphoglucomutase (PGM) isoenzyme patterns in bloodstains present on silver. The effect could be produced by treating blood samples with silver nitrate solution.