Single Human Hair Research Articles

Induction heating-electrothermal vaporization for direct mercury analysis of a single human hair strand by inductively coupled plasma mass spectrometry

It was demonstrated that a single human hair strand can be analyzed for total mercury using an induction heating-electrothermal vaporizer with ICP-MS detection, achieving a detection limit of 20 pg or 30 ng g−1 (based on a 0.6 mg sample).

Direct detection of mercury in single human hair strands by laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS)

Single shot laser ablation ICP-MS has demonstrated the potential to detect Hg in single human hairs with a resolution corresponding to less than one day of growth and with a detection limit of approximately 0.2 μg g−1.

Symmetrically Tapered <30-μm-thick Quasi-Planar Germanium Waveguides as Chemical Sensors for Microanalysis

Symmetrically tapered planar IR waveguides have been fabricated by starting with a ZnS coated concave piece of single-crystal Ge, embedding it in an epoxide resin as a supporting substrate, and then grinding and polishing a planar surface until the thickness at the taper minimum is <30 μm. Such tapering is expected to enhance a waveguide's sensitivity as an evanescent wave sensor by maximizing the amount of evanescent wave energy present at the thinnest part of the waveguide. As predicted by theory, the surface sensitivity, i.e., the absorbance signal per molecule in contact with the sensing region, increases with decreasing thickness of the tapered region even while the total energy throughput decreases. The signal-to-noise ratio obtained depends very strongly on the quality of the polished surfaces of the waveguides. The surface sensitivity is superior to that obtained with a commercial Ge attenuated total reflection (ATR) accessory for several types of sample, including thin films (<10 ng) and small volumes (<1 μL) of volatile solvents. By using the waveguides, light-induced structural changes in the protein bacteriorhodopsin were observable using samples as small as ∼50 pmol (∼1 μg). In addition, the waveguide sensors can reveal the surface compositions on a single human hair, pointing to their promise as a tool for forensic fiber analysis.

Is the α–β transition of keratin a transition of α-helices to β-pleated sheets. II. Synchrotron investigation for stretched single specimens

This article investigates the fashion of structural development along wool and human hair keratinous fibres during stretching. It is shown that necking phenomenon can be observed for the specimens stretched to yield region. X-ray diffraction investigation was carried out using synchrotron radiation for stretched single human hair and wool keratinous fibres. The results showed that the α–β transition was closely related to the necking deformation. The un-necked segments remained the α-form crystallinity; necking paved way to the α–β transition in later steam setting process. These results are consistent with the structural behaviour observed for polymers, indicating that keratin shares the same structural characteristics with polymers.

Something from nothing

The title is somewhat wrong and should be, more accuratematerial remains; however, a microscope slide bearing a ly, 'something from very little'. Recent years have seen stain extract containing spermatozoa may have been some dramatic advances in forensic science particularly in retained. It is this slide that the officer requests to be found the field of DNA profiling. The 'very little' could be a and if possible DNA profiled. microscope slide bearing some spermatozoa or a plastic bag containing a single human hair. The examination of such by the most recent techniques has had a dramatic impact on some old unsolved crime cases. Many more of these old cold cases could merit a thorough review to seek out forensic opportunities.

Bridging the Digital Divide with Universal Access

No abstract available.

Genes for a range of growth factors and cyclin-dependent kinase inhibitors are expressed by isolated human hair follicles

The mRNA expressions of various growth regulatory molecules in single human anagen hair follicles were analysed by reverse transcription and polymerase chain reaction. Approximately 370 hair follicles were isolated from 20 normal individuals, and 0.90 +/- 0.34 microgram (mean +/- SD) total RNA was extracted per whole hair follicle. The mRNAs of fibroblast growth factor (FGF)-1, FGF-2, FGF-5, FGF-7, transforming growth factor (TGF)-alpha, TGF-beta 1, hepatocyte growth factor, insulin-like growth factor (IGF)-I, tumour suppressor gene p53 and high sulphur protein were detected in most or all of the examined hair follicles per target gene. In contrast, none of the mRNAs of FGF-3, FGF-4, FGF-6, FGF-9 and IGF-II was detected, and those of TGF-beta 2 and TGF-beta 3 were detected in only a limited number of the examined hair follicles. Among cyclin-dependent kinase inhibitors, the mRNAs of p21waf1/cip1 and p27kip1 were expressed in almost all the hair follicles, while those of p15INK4B and p16INK4A were not detected. These results suggest that both positive and negative factors for the proliferation and differentiation of follicular epithelial cells coexist in a human anagen hair follicle.

Isoelectric Focusing of Human Hair Keratins: Correlation with Sodium Dodecyl Sulfate-Polyacrylamide Gel Electrophoresis (SDS-PAGE) Patterns and Effect of Cosmetic Treatments

A new isoelectric focusing (IEF) technique in polyacrylamide gels with 6M urea and 1.5% Nonidet P40 has been developed to characterize human hair samples. The phenotypes demonstrated with this procedure has been correlated with the sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) patterns described by other authors. The method described can be applied in the forensic science analysis of a single human hair. Using the same IEF technique we have studied the changes in electrophoretic patterns of cosmetically treated hair. The characteristics of the modifications observed and its utility in forensic science work are also discussed in this paper.

Polymerase chain reaction: relevance for dermatopathology

Medical knowledge has been significantly expanded by the techniques of molecular genetics. A new technology, the polymerase chain reaction (PCR) (1–6), has produced a quantum leap in the field of molecular genetics. PCR uses an in vitro chemical reaction to amplify impure DNA, either fragmented or intact. A defined DNA fragment can be amplified a millionfold in a relatively brief incubation (a few hours). The ability to amplify minute quantities of crude DNA gives the method extraordinary power and sensitivity, DNA can be amplified from fixed pathologic specimens (7), buccal cells from mouth washes (8), a single human hair (9), and solitary cells (10). Once amplified, large DNA samples can be studied by electrophoresis, Southern and slot blot, and other techniques.

DNA typing from single hairs.

The characterization of genetic variation at the DNA level has generated significant advances in gene and disease mapping, and in the forensic identification of individuals. The most common method of DNA analysis, that of restriction fragment length polymorphism (RFLP), requires microgram amounts of relatively undegraded DNA for multi-locus typing, and hundreds of nanograms for single-locus comparisons. Such DNA frequently cannot be obtained from forensic samples such as single hairs and blood stains, or from anthropological, genetic or zoological samples collected in the field. To detect polymorphic DNA sequences from single human hairs, we have used the polymerase chain reaction (PCR), in which specific short regions of a gene can be greatly amplified in vitro from as little as a single molecule of DNA. We have detected genetically variable mitochondrial and nuclear DNA sequences from the root region of shed, as well as freshly-plucked, single hairs; mitochondrial DNA (mtDNA) sequences have been detected in a sample from a single hair shaft. We have used three different means of DNA typing on these samples: the determination of amplified DNA fragment length differences, hybridization with allele-specific oligonucleotide probes, and direct DNA sequencing.

IR spectral depth profiling using fourier transform photothermal beam deflection

FTIR photothermal beam-deflection spectroscopy (PBDS) was used to make spectral depth-profiling measurements with synthetic bilayer samples of polyethylene/nitrocellulose, with a commercial plastic having surface printing and with a single human hair. A Digilab interferometer modified to operate at several scan speeds was used to record the spectra, without the cell-resonance problems found with photoacoustic spectroscopy (PAS). The utility of spectral depth profiling is discussed; significant S/N improvements seem to be needed and, with either PBDS or PAS, a wider range of modulation frequencies is required for the methods to be useful.

Phosphoglycerate kinase deficiency: biochemical studies on hair follicles.

A fluorimetric procedure for the determination of phosphoglycerate kinase in single human hair follicles is described. Enzyme studies on different parts of hair follicles after dissection show that the distribution of glucose-6-phosphate dehydrogenase matches that of phosphoglycerate kinase. Glucose-6-phosphate dehydrogenase can therefore be used as a reference enzyme to compensate for differences in hair follicle sizes. It was shown that the variation in the values found in individual hair follicles is improved by relating phosphoglycerate kinase to glucose-6-phosphate dehydrogenase activity. In areas of the world where glucose-6-phosphate dehydrogenase deficiency occurs frequently, an autosomally inherited reference enzyme may be preferred. It is shown that 6-phosphogluconate dehydrogenase is useful in this respect. Upon storage a gradual drop in the activity of all three enzymes was observed, but the rate of decrease was about equal: the enzyme activity ratio was, therefore, almost unaffected for a period of one week. This allows the determination of phosphoglycerate kinase even in mailed hair follicles.

Detection of Methamphetamine and Amphetamine in a Single Human Hair by Gas Chromatography/Chemical Ionization Mass Spectrometry

A detailed procedure of an extremely sensitive method for quantitation of methamphetamine and amphetamine in human hair by gas chromatography (GC)/chemical ionization (CI) mass spectrometry (MS) is presented. N-methylbenzylamine was used as an internal standard. The samples, after extraction with an organic solvent, were derivatized with trifluoroacetic anhydride before the GC/MS analysis. Quantitation was made with quasi-molecular ions of the derivatives by selected ion monitoring in the CI mode. The detection limit was about 10 pg in an injected volume. The high sensitivity enabled us to measure both stimulants in a single human hair in actual cases.

Normalization of PIXE measurements along single human hairs by nuclear reaction

In simultaneous (d,p) reaction and deuteron induced X-ray measurements the N/C and S/N ratios were found to be constant along a single hair, therefore the sulphur K X-ray intensity was suggested for normalizing PIXE spectra.

Infrared Spectra of a Single Human Hair

Abstract We have recently shown that it is possible to carry out nondestructive infrared (IR) spectroscopic studies of solid objects which are very large1–4. It is, however, of equal interest to be able to examine objects which are very small. Consequently, we have recorded spectra of a single human hair, using IR Fourier transform photothermal beam deflection spectroscopy (PBDS)1–8.

Measurements of Trace Element Concentration Profiles across the Diameter of Human Hair with Micro-PIXE

Trace element distributions across single human hairs using a proton microbeam has been measured to study the origin of these elements in hair. A new way of concentration assignment for micro PIXE making use of both the Proton Induced characteristic X-rays and the Rutherford Backscattered protons is reported.

The Absorption of Mercuric Ion into Single Human Head Hairs

The concentration patterns of radioactive Hg++, Cu++, and I- in individual hair shafts, after soaking in aqueous solutions of these tracers, were measured nondestructively to permit repeated experiments on a given shaft. The mercury concentrations generally increased from the root end to the distal end of a given shaft less steeply than those of copper, while iodide concentrations generally decreased. Concentration peaks and other pattern features for mercury were also relatively less intense, but there was some correlation of the position of such areas of increased mercury, copper, and iodine adsorption in a given shaft. At equilibrium after more than 100 h of soaking, the amount of mercury taken up at pH 8 by the hair was three to four times that at pH 3. The rate of absorption of mercury was higher at low pH values, and that of desorption higher at high pH values. The relative intensity of pattern features remained constant during absorption or desorption at a given pH, but changed if the pH was changed. These data are discussed in terms of the chemistry of the hair binding sites for cations and anions.

Multiple Enzyme Typing of the Sheath Cells Associated with the Root of a Single Human Head Hair

Multiple-enzyme typing of the cellular material associated with single human head hairs can be achieved quite readily using cut sections of hair, and 60/100 petroleum ether to dissolve the XAM mountant. Both the PGM 1 (IEF) and GLO I systems could be determined from hair sections after 2 months and PGM 1 typing of the sheath cells associated with complete hairs, from some donors, has been achieved after 4 months storage in XAM. EsD activity was lost after storage in XAM and typing was rarely possible even with air storage for periods in excess of 4 weeks.

Absorption Patterns for 32P Phosphate into Single Human and Animal Hairs

Absorption of phosphate into single human and animal hair shafts has been studied by means of 32P radiotracer techniques. Nondestructive radioassay permitted repetitive experiments on the same hair specimen. Phosphate concentration patterns were shown to be complementary to those for zinc absorption and sometimes to exhibit prominent concentration peaks extending over regions of the shaft 10 to 20 mm in length. Appearance of such peaks was shown to be favored by pH decreasing below 7 but not by migration of phosphate along the hair shaft, which was unimportant.

The Absorption of Arsenic into Single Human Head Hairs

Single head hairs from several subjects have been soaked in arsenic radiotracer solution and the arsenic absorbed on 2-mm hair segments has been determined by radioactivity assay. The absorption patterns were characterized for some subjects by regions of high uptake where (in other hairs from the same subject) regions of low uptake of copper and zinc were found, and vice versa. These data have been interpreted in terms of varying densities of binding sites in the hair structure, with specific chemical character. Arsenic absorption patterns for other subjects were highly structured, showing zones of very high and very low absorption. The dangers of interpreting similar patterns for the indigenous arsenic content of hair in terms of the dates on which elevated arsenic ingestion took place have been discussed.