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1.
Morphological changes in hair subjected to decontamination protocols were evaluated by scanning electron microscopy (SEM) as part of the National Laboratory Certification Program's (NLCP) efforts to develop proficiency testing materials in support of Federal Workplace Drug Testing programs. Hair from five different donors was evaluated. Hair samples were subjected to three decontamination protocols: (1) aqueous phosphate buffer, (2) methanol or (3) methylene chloride as models for aqueous, alcohol and polar organic solvent protocols, respectively. Under these protocols, samples of hair were treated for 225 min (aqueous), 15 min (alcohol), or 15 min (polar organic). After decontamination, hair strands were sputter coated with gold/palladium (AuPd) and observed by SEM. Modest lifting of cuticle scales was observed in hair treated with methanol and methylene chloride consistent with some changes to the cell membrane complex (CMC) between cuticle scales. Damage resulting from aqueous buffer treatment ranged from substantial degradation to apparent complete loss of cuticle scales. Fracture structures consistent with cuticle damage were also observed. Each decontamination protocol had a different impact on the cuticle of the hair shaft.  相似文献   

2.
The author presents the data on microclues in the free edges of hair cuticles of human head: microinjuries, microdefects (cracks, breaks, clefts, large and small waves) in representatives of Asia, Africa, Latin America, and Eastern Europe. The studies were carried out by scanning electron microscopy. Microinjuries of cuticle cells forming during hair combing by different types of combs and as a result of "permanent" curling are described. Scanning electron microscopy at the optimal magnification of x 3000 is a highly informative method for investigating microinjuries to the hair cuticle as additional signs in expert evaluation of the hair.  相似文献   

3.
The morphology of hairs from the head, beard, chest, armpits, and pubis was studied in indigenous population of Sudan, Sierra-Leone, Cote d'Ivoir, Ruanda, Nigeria, Gambia, Kenya, Uganda, Burundi, Zaire, Southern African Republic, Angola, Benin, and Guinea Bissau. A total of 327 hair specimens were examined. A number of new parameters of hairs were determined: thickness, number of cuticle pattern lines per mm, optic edge pattern, cuticle patterns, methods for detecting the cortical and medullar layers, width of hair layers and their transverse sections. The resultant morphological signs are new specific signs for African residents (Negroid) which can be used in forensic medical studies for identifying the race appurtenance of hairs.  相似文献   

4.
人发毛干角蛋白电泳谱型的分析   总被引:2,自引:1,他引:2  
本文用SDS-梯度(5.0~17.0%)聚丙烯酰胺凝胶电泳对150例中国人头发角蛋白组分进行了分析。结果表明,在150例人头发中,有6种不同类型的角蛋白电泳谱型。此1~6型发生频率分别为24%、12%、42%、7.3%、8.0%;及6.7%。用N-(3-芘)马来酰胺标记头发角蛋白巯基,证实人头发不同类型的角蛋白电泳谱型主要区别在低硫蛋白部位。作者认为,人头发角蛋白电泳谱型的差异可为法医学鉴定中的毛发个人识别提供重要的依据。  相似文献   

5.
Dorsal guard hairs of four species of bear (family: Ursidae) found in India were characterized using light microscopy by studying features including colour, hair thickness, cuticle pattern, medulla pattern, medullary index, cross-section and scale count index. The gross cuticular pattern was quite similar for the four species but a distinct difference was observed in the scale count index. Medulla type was narrow and amorphous with a very low medullary index (< 0.15) except for brown bear which showed a comparatively higher medullary index (0.38) and a vacuolated medulla. By combining together the parameters mentioned above it was possible to characterize bear species on the basis of their hair characteristics.  相似文献   

6.
The structure of hairs from the head, chest, armpits, and pubis of residents of Latin America (Bolivia, Salvador, Panama, Ecuador, Chile, Nicaragua, Venezuela, Peru, Brasil, and Mexico) has been studied. New data on macro- and microscopic characteristics of hairs of the population of the above countries were obtained (color, shape, length, thickness of hair; number of cuticle lines; characteristics of hair layers, shapes of transverse sections, etc.).  相似文献   

7.
Abstract:  It is generally accepted that nuclei degrade in developing hair shafts but the point at which such occurs has not been investigated. The fate of mitochondria in the keratinizing hair shaft has been less clear. This study uses transmission electron microscopy to investigate when nuclei and mitochondria are no longer visible in the developing hair shaft. Serial sections were obtained from anagen head hairs absent follicles in order to determine the sequence of degradation of nuclei and mitochondria in the hair shaft by starting at the root bulb and proceeding toward the hair tip. It was demonstrated that nuclei and mitochondria become invisible in the keratinizing hair shaft at about the same time. This was found to occur fairly early in the process at the level of the hair shaft where the hair cuticle becomes permanent.  相似文献   

8.
This paper presents an overview of the most common sectioning patterns utilised in the analysis of hair for drug use; report on the major user groups (sectors) that currently make use of hair analysis in the United Kingdom (UK); present the results for the different drug groups analysed in samples of hair samples analysed at TrichoTech between 2001 and 2005.A total of 186,084 tests on 34,626 hair samples were performed for the commonly requested drug groups. There were 145,799 enzyme-linked Immunosorbent positive screening tests (ELISA), which were subsequently confirmed by gas chromatography equipped with mass spectrometry detection (GC–MS). The two major sectors were the Medico-Legal sector (65%) and Workplace (20%). Police (Forensics), Clinical Monitoring, Schools, Research and Insurance accounted together for the remaining 15% of the samples. Combinations of several sections patterns were requested covering periods from the most recent month up to 24 months. The most common sectioning pattern was one single section measuring 3 cm, to cover the most recent 3 months (44%), which in some cases was complemented by a further 3 cm to cover together 6 months (13%). The second most common sectioning pattern was the analysis of three sections of 1 cm each to cover the most recent 3 months (28%), when a more detailed evaluation of drug use pattern was relevant. Samples collected from other areas of the body such as axilla, pubic, chest, beard and leg, constituted 6% of the samples. The analysis of monthly sections plays an important role in the evaluation and interpretation of drug use, particularly in certain Medico-Legal cases. The sectors with the highest rates of positive results were Police (Forensics) (78%), Medico-Legal (62%) and Clinical (54%). The common drugs in each group were cannabinol (27%), cocaine (25%), morphine (17%), amphetamine (13%) and diazepam (15%). The positive rate for the Workplace sector was 10%. The most common drugs detected in the Workplace samples in each group were: THC (4%), codeine (2%), cocaine (2%), MDMA (0.5%) and diazepam (0.1%). The concentration levels of drugs found in samples from the workplace were lower than in the other sectors (95% of cases). The exceptions were for dihydrocodeine and MDMA, where levels were 170 and 143% higher, respectively. However, the maximum levels detected in the Workplace samples were lower. The Medico-Legal sector is the most prevalent sector using hair analysis in the UK but the rate of Workplace sector use of hair testing is increasing. One in 10 workplace hair tests detected the presence of at least one drug, which is twice the rate of detection using urine, which is a 1 in 20 urine sample. This means that the chances of identifying people on drugs in the workplace by testing hair samples are twice as likely than urine samples.  相似文献   

9.
In this study, the effects of fibre type, hair style, time and fibre persistence on the secondary transfer of mask fibres to pillowcases via head hair were studied. Volunteers with a range of hair styles, and masks consisting of different fibre compositions were used in the study. Fibres from the masks were found to transfer from donor subjects to the pillowcases up to 14 nights after the mask had been worn. On average, the number of secondarily transferred fibres found decreased with time; however, this decrease appeared to be more 'linear' in nature, rather than an exponential decay. The greatest degree of secondary transfer occurred with cotton, then acrylic, then wool. In a primary transfer/persistence experiment with a 50% acrylic/50% wool mask, wool was found to persist in the hair more readily than acrylic. The results also showed that the greatest degree of secondary transfer occurred via short straight and long straight hair, with no clear pattern emerging between medium length hair (both straight and curly) and with long curly hair. The implications of these findings for the assessment and interpretation of casework are considered along with data obtained from related studies.  相似文献   

10.
Data on the form of transversal sections and pattern of pigmental granulations of hair obtained from the inhabitants of some countries of Asia, Africa and Latin America are presented. These hair characteristics were compared to those of hair obtained from the USSR citizens (Russian, Buelorussian, Ukrainian, Georgian, Azerbaijanian people). Possibility of race identification of hair using set of morphological characteristics is stressed.  相似文献   

11.
Most tissues encountered in forensic biology laboratories have been previously characterized with electron microscopy due to their medical importance. Anagen hair root cells, epithelial cells, erythrocytes, neutrophils, osteocytes, and spermatozoa have received considerable research attention at the ultrastructural level. There is no literature indicating that cells attached to removed telogen hair roots have been characterized with transmission electron microscopy. Nonetheless, telogen hairs are a frequent submission item to forensic laboratories for DNA typing. The amount of tissue attached to a telogen hair root usually determines whether that hair is suitable for nuclear DNA typing methods or mitochondrial DNA typing methods. This study used transmission and scanning electron microscopy to characterize the tissues found in three commonly occurring telogen hair root forms. The tissues were found to consist of keratinized remnant follicle, nonnucleated epithelial cells, nucleated epithelial cells, and trichilemmal keratin. These findings were consistent with the known principles of hair follicle regression. The recognition of the root structures that contain these specific tissue types may assist in the DNA typing of telogen hairs inasmuch as the quality of tissue present may be more important than the amounts of tissue present.  相似文献   

12.
Thallium has been responsible for many intoxications since its discovery; however, toxicological profiles for thallium in human fatalities have not been updated recently. Autopsy, microscopic investigations, and toxicological analyses were performed on a married couple who died from thallium sulfate intended homicidal poisoning. The distribution of thallium was established by inductively coupled plasma mass spectrometry with hair samples showing the highest thallium concentration. Electron microscopy revealed a dystrophic condition of hair with disorganized cuticle and atrophy of the hair bulb. Thallium interacts with cells at different levels, with prominent ultrastructural injuries in the mitochondria and endoplasmic reticulum, and high concentration of electron dense granules observed in the cytoplasm and mitochondria of several organs. Alopecia, toxic encephalopathy, and peripheral neuropathy were diagnosed in the victims and suggested to be crucial implications for thallium poisoning. The analytical procedures used in this case are of considerable forensic importance in the diagnosis of thallium poisoning.  相似文献   

13.
Stab wounds upon bone are analyzed to interpret the weapon used and the physical context in which the attack occurred. The literature demonstrates that most research conducted pertaining to wound patterns has been carried out on defleshed and unclothed bone samples, not adequately replicating actual circumstances. For this research, six half pig torsos (Sus scrofa), fleshed (including muscle, fat, epidermis, and dermis layers) and clothed, were stabbed using three knife types, applying both straight and downward thrusts. Analysis conducted macroscopically and through a scanning electron microscope with an environmental secondary electron detector revealed a general lack of consistency in wound pattern and associated secondary effects. Consequently, it was not possible to establish wound pattern per knife type as suggested in previous research or relate it to stab motion. Advantage of microscopic analysis was evident in recognizing wound traits and observation of trace evidence not visible macroscopically.  相似文献   

14.
15.
常染色体STR基因座三带型的观察与分析   总被引:1,自引:1,他引:0  
目的观察亲子鉴定常用STR基因座的三带型现象,分析探讨其特点。方法分析11985例亲子鉴定(含29111个个体)的STR分型数据,筛选三带型事件,统计三带型的频率并分析三带型的特点。结果三带型的检出总频率为0.0721%(21/29111),其中D21Sll检出率最高,为0.0172%(5/29111);D18S51检出率为0.0137%(4/29111);FGA检出率为0.0103%(3/29111)。Typel三带型携带者随机传递一个等位基因给子代,Type2携带者可遗传两个等位基因给子代。结论三带型结果较少见,判读须慎重。  相似文献   

16.
This article discusses the immunoassay screening of pain management drugs, and the mass spectrometric confirmation of fentanyl in human hair. Hair specimens were screened for fentanyl, opiates (including oxycodone), tramadol, propoxyphene, carisoprodol, methadone, and benzodiazepines and any positive results were confirmed using gas chromatography or liquid chromatography with mass spectral detection. The specific focus of the work was the determination of fentanyl in hair, since autopsy specimens were also available for comparison with hair concentrations. Using two-dimensional gas chromatography with electron impact mass spectrometric detection, fentanyl was confirmed in four of nine hair specimens collected at autopsy. The accuracy of the assay at 10 pg/mg was 95.17% and the inter-day and intra-day precision was 5.04 and 13.24%, respectively (n=5). The assay was linear over the range 5-200 pg/mg with a correlation of r(2)>0.99. The equation of the calibration curve forced through the origin was y=0.0053x and the limit of quantitation of the assay was 5 pg/mg. The fentanyl concentrations detected were 12, 17, 490, and 1930 pg/mg and the results were compared with toxicology from routine post-mortem analysis. The screening of pain management drugs in hair is useful in cases where other matrices may not be available, and in routine testing of hair for abused drugs.  相似文献   

17.
Keratin characterization through electrophoretic techniques has been used for species identification in forensic science and in taxonomic studies. In the present work, protein components solubilized from hair of non-human primates were evaluated to investigate whether there is any species-specific pattern in an evolutionary perspective, by grossly comparing hair native keratins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and isoelectric focusing (IEF). Extracted hair keratins for all specimens were separated by SDS-PAGE into 2–3 polypeptide bands with apparent MW in the range 39–54 kDa and into 3–7 polypeptide bands with apparent MW in the range 10–35 kDa. With this technique it was possible to distinguish different suborders, different families of the same suborder, and, sometimes, different genera from the same family. On the contrary, it was not possible to distinguish different species of the same genus and different specimens of the same species. With IEF, extracted hair keratins were separated into about 30 polypeptide bands with pI values in the range of pH 3.9–7.7. IEF discriminates poorly between different samples. Only in specimens from Papio genus did we find an additional polypeptide band. In conclusion, we found that the differences between electrophoretic patterns are largest for animals that are not closely related while specimens of the same species have the same patterns.  相似文献   

18.
We report here a review of the seventh mitochondrial DNA (mtDNA) exercise undertaken by the Spanish and Portuguese working group (GEP) of the International Society for Forensic Genetics (ISFG) corresponding to the period 2003-2004. Five reference bloodstains from five donors (M1-M5), a mixed stain of saliva and semen (M6), and a hair sample (M7) were submitted to each participating laboratory for nuclear DNA (nDNA; autosomal STR and Y-STR) and mtDNA analysis. Laboratories were asked to investigate the contributors of samples M6 and M7 among the reference donors (M1-M5). A total of 34 laboratories reported total or partial mtDNA sequence data from both, the reference bloodstains (M1-M5) and the hair sample (M7) concluding a match between mtDNA profiles of M5 and M7. Autosomal STR and Y-STR profiling was the preferred strategy to investigate the contributors of the semen/saliva mixture (M6). Nuclear DNA profiles were consistent with a mixture of saliva from the donor (female) of M4 and semen from donor M5, being the semen (XY) profile the dominant component of the mixture. Strikingly, and in contradiction to the nuclear DNA analysis, mtDNA sequencing results yield a more simple result: only the saliva contribution (M4) was detected, either after preferential lysis or after complete DNA digestion. Some labs provided with several explanations for this finding and carried out additional experiments to explain this apparent contradictory result. The results pointed to the existence of different relative amounts of nuclear and mtDNAs in saliva and semen. We conclude that this circumstance could strongly influence the interpretation of the mtDNA evidence in unbalanced mixtures and in consequence lead to false exclusions. During the GEP-ISFG annual conference a validation study was planned to progress in the interpretation of mtDNA from different mixtures.  相似文献   

19.
The metabolite-to-parent drug ratios were determined in the hair of 2444 methamphetamine (MA) abusers who had produced MA-positive hair results from 2001 to May 2005 and in the hair of 53 ecstasy abusers who had produced positive methylenedioxymethamphetamine (MDMA) hair results from 2002 to May 2005. For the hair analyses, hair strands were washed, cut into small pieces and extracted for 20 h in 1 mL methanol containing 1% HCl. Drugs in the extract were determined by gas chromatography-mass spectrometry (GC-MS) using selective ion monitoring after derivatization with trifluoroacetic anhydride. The six range groups were divided as follows on the basis of MA concentrations in hair (n = 2389): 0.5-5 ng/mg (n = 950), 5-10 ng/mg (n = 582), 10-20 ng/mg (n = 503), 20-30 ng/mg (n = 160), 30-40 ng/mg (n = 80), more than 40 ng/mg (n = 114) to assess the correlations between MA concentrations and metabolite-to-parent drug ratios. In groups of higher MA concentrations, lower ratios of AP/MA were found, and there was a statistically significant difference among six range groups. Comparisons of age groups (tens, twenties, thirties, forties, fifties, and sixties) and male and female subjects for the ratios of AP/MA showed a statistically significant difference. The detection of metabolites and the parent drug with reasonable ratios was found to be a useful indicator for distinguishing internal drug incorporation from external contamination. In our study, MA users can produce 0.4-116% (mean = 9%) of amphetamine (AP) concentrations in hair, and ecstasy users 1-110% (mean = 12%) of methylenedioxyamphetamine (MDA) in appropriately washed hair samples.  相似文献   

20.
吴延溢 《河北法学》2003,21(6):19-23
人们通常将宪法监督模式在总体上划分为四种典型的类型,即立法机关监督型、司法机关监督型、宪法委员会监督型和宪法法院监督型。不同的国家之所以要选择不同的模式,存在着诸多方面的原因,如理论基础、法律传统、历史际遇、司法体制等。对宪法监督模式差异性的成因进行多角度的考察,对我国宪法监督制度的改革有着十分重要的意义。  相似文献   

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