| 1. |
- Wang, Chao, et al.
(författare)
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The role of pro-inflammatory S100A9 in Alzheimer's disease amyloid-neuroinflammatory cascade
- 2014
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Ingår i: Acta Neuropathologica. - : Springer Science and Business Media LLC. - 0001-6322 .- 1432-0533. ; 127:4, s. 507-522
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Tidskriftsartikel (refereegranskat)abstract
- Pro-inflammatory S100A9 protein is increasingly recognized as an important contributor to inflammation-related neurodegeneration. Here, we provide insights into S100A9 specific mechanisms of action in Alzheimer's disease (AD). Due to its inherent amyloidogenicity S100A9 contributes to amyloid plaque formation together with A beta. In traumatic brain injury (TBI) S100A9 itself rapidly forms amyloid plaques, which were reactive with oligomer-specific antibodies, but not with A beta and amyloid fibrillar antibodies. They may serve as precursor-plaques for AD, implicating TBI as an AD risk factor. S100A9 was observed in some hippocampal and cortical neurons in TBI, AD and non-demented aging. In vitro S100A9 forms neurotoxic linear and annular amyloids resembling A beta protofilaments. S100A9 amyloid cytotoxicity and native S100A9 pro-inflammatory signaling can be mitigated by its co-aggregation with A beta, which results in a variety of micron-scale amyloid complexes. NMR and molecular docking demonstrated transient interactions between native S100A9 and A beta. Thus, abundantly present in AD brain pro-inflammatory S100A9, possessing also intrinsic amyloidogenic properties and ability to modulate A beta aggregation, can serve as a link between the AD amyloid and neuroinflammatory cascades and as a prospective therapeutic target.
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| 2. |
- Carvalho, Alexandra T. P., et al.
(författare)
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Understanding the structural and dynamic consequences of DNA epigenetic modifications : Computational insights into cytosine methylation and hydroxymethylation
- 2014
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Ingår i: Epigenetics. - : Informa UK Limited. - 1559-2294 .- 1559-2308. ; 9:12, s. 1604-1612
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Tidskriftsartikel (refereegranskat)abstract
- We report a series of molecular dynamics (MD) simulations of up to a microsecond combined simulation time designed to probe epigenetically modified DNA sequences. More specifically, by monitoring the effects of methylation and hydroxymethylation of cytosine in different DNA sequences, we show, for the first time, that DNA epigenetic modifications change the molecule's dynamical landscape, increasing the propensity of DNA toward different values of twist and/or roll/tilt angles (in relation to the unmodified DNA) at the modification sites. Moreover, both the extent and position of different modifications have significant effects on the amount of structural variation observed. We propose that these conformational differences, which are dependent on the sequence environment, can provide specificity for protein binding.
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| 3. |
- Abelein, Axel, et al.
(författare)
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The hairpin conformation of the amyloid beta peptide is an important structural motif along the aggregation pathway
- 2014
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Ingår i: Journal of Biological Inorganic Chemistry. - : Springer Science and Business Media LLC. - 0949-8257 .- 1432-1327. ; 19:4-5, s. 623-634
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Forskningsöversikt (refereegranskat)abstract
- The amyloid beta (A beta) peptides are 39-42 residue-long peptides found in the senile plaques in the brains of Alzheimer's disease (AD) patients. These peptides self-aggregate in aqueous solution, going from soluble and mainly unstructured monomers to insoluble ordered fibrils. The aggregation process(es) are strongly influenced by environmental conditions. Several lines of evidence indicate that the neurotoxic species are the intermediate oligomeric states appearing along the aggregation pathways. This minireview summarizes recent findings, mainly based on solution and solid-state NMR experiments and electron microscopy, which investigate the molecular structures and characteristics of the A beta peptides at different stages along the aggregation pathways. We conclude that a hairpin-like conformation constitutes a common motif for the A beta peptides in most of the described structures. There are certain variations in different hairpin conformations, for example regarding H-bonding partners, which could be one reason for the molecular heterogeneity observed in the aggregated systems. Interacting hairpins are the building blocks of the insoluble fibrils, again with variations in how hairpins are organized in the cross-section of the fibril, perpendicular to the fibril axis. The secondary structure propensities can be seen already in peptide monomers in solution. Unfortunately, detailed structural information about the intermediate oligomeric states is presently not available. In the review, special attention is given to metal ion interactions, particularly the binding constants and ligand structures of A beta complexes with Cu(II) and Zn(II), since these ions affect the aggregation process(es) and are considered to be involved in the molecular mechanisms underlying AD pathology.
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| 4. |
- Gingerich, Joseph A. M., et al.
(författare)
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Fluted point manufacture in eastern North America : an assessment of form and technology using traditional metrics and 3D digital morphometrics
- 2014
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Ingår i: World archaeology. - : Informa UK Limited. - 0043-8243 .- 1470-1375. ; 46:1, s. 101-122
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Tidskriftsartikel (refereegranskat)abstract
- Differences in Paleoindian projectile point morphology have previously been used to define technologies, infer colonization patterns, propose chronological and regional boundaries. In this study, we evaluate the effectiveness of traditional linear measurements and ratios, flake scar angles, and 3D model-based flake contours for the statistical differentiation of projectile point type(s) and reduction technique. Sixty-three fluted bifaces from eastern North America and fourteen replicate Clovis points are analyzed. Discriminant analysis shows that 3D model-based Fourier descriptors of flake scar contours are less successful than traditional metrics in correctly differentiating styles, but more successful in identifying individual knappers. Changes in the symmetry of front and back flake scars between Clovis and later fluted point styles indicate a possible shift in reduction techniques. These findings demonstrate the usefulness of both traditional and modern morphometric variables to quantify biface morphology, and address questions about social interaction and technological change in Pleistocene North America.
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| 5. |
- Lindgren, Joel, et al.
(författare)
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Engineered non-fluorescent Affibody molecules facilitate studies of the amyloid-beta (A beta) peptide in monomeric form : Low pH was found to reduce A beta/Cu(II) binding affinity
- 2013
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Ingår i: Journal of Inorganic Biochemistry. - : Elsevier BV. - 0162-0134 .- 1873-3344. ; 120, s. 18-23
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Tidskriftsartikel (refereegranskat)abstract
- Aggregation of amyloid-beta (A beta) peptides into oligomers and amyloid plaques in the human brain is considered a causative factor in Alzheimer's disease (AD). As metal ions are over-represented in AD patient brains, and as distinct A beta aggregation pathways in presence of Cu(II) have been demonstrated, metal binding to A beta likely affects AD progression. A beta aggregation is moreover pH-dependent, and AD appears to involve inflammatory conditions leading to physiological acidosis. Although metal binding specificity to A beta varies at different pH's, metal binding affinity to A beta has so far not been quantitatively investigated at sub-neutral pH levels. This may be explained by the difficulties involved in studying monomeric peptide properties under aggregation-promoting conditions. We have recently devised a modified Affibody molecule, Z(A beta 3)(12-58), that binds A beta with sub-nanomolar affinity, thereby locking the peptide in monomeric form without affecting the N-terminal region where metal ions bind. Here, we introduce non-fluorescent A beta-binding Affibody variants that keep A beta monomeric while only slightly affecting the A beta peptide's metal binding properties. Using fluorescence spectroscopy, we demonstrate that Cu(II)/A beta(1-40) binding is almost two orders of magnitude weaker at pH 5.0 (apparent K-D = 51 mu M) than at pH 7.3 (apparent K-D = 0.86 mu M). This effect is arguably caused by protonation of the histidines involved in the metal ligandation. Our results indicate that engineered variants of Affibody molecules are useful for studying metal-binding and other properties of monomeric A beta under various physiological conditions, which will improve our understanding of the molecular mechanisms involved in AD.
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| 6. |
- Luo, Jinghui, et al.
(författare)
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Cellular Polyamines Promote Amyloid-Beta (A beta) Peptide Fibrillation and Modulate the Aggregation Pathways
- 2013
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Ingår i: ACS Chemical Neuroscience. - : American Chemical Society (ACS). - 1948-7193. ; 4:3, s. 454-462
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Tidskriftsartikel (refereegranskat)abstract
- The cellular polyamines spermine, spermidine, and their metabolic precursor putrescine, have long been associated with cell-growth, tumor-related gene regulations, and Alzheimer's disease. Here, we show by in vitro spectroscopy and AFM imaging, that these molecules promote aggregation of amyloid-beta (A beta) peptides into fibrils and modulate the aggregation pathways. NMR measurements showed that the three polyamines share a similar binding mode to monomeric A beta(1-40) peptide. Kinetic ThT studies showed that already very low polyamine concentrations promote amyloid formation: addition of 10 mu M spermine (normal intracellular concentration is similar to 1 mM) significantly decreased the lag and transition times of the aggregation process. Spermidine and putrescine additions yielded similar but weaker effects. CD measurements demonstrated that the three polyamines induce different aggregation pathways, involving different forms of induced secondary structure. This is supported by AFM images showing that the three polyamines induce A beta(1-40) aggregates with different morphologies. The results reinforce the notion that designing suitable ligands which modulate the aggregation of A beta peptides toward minimally toxic pathways may be a possible therapeutic strategy for Alzheimer's disease.
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| 7. |
- Luo, Jinghui, et al.
(författare)
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Endogenous Polyamines Reduce the Toxicity of Soluble A beta Peptide Aggregates Associated with Alzheimer's Disease
- 2014
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1525-7797 .- 1526-4602. ; 15:6, s. 1985-1991
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Tidskriftsartikel (refereegranskat)abstract
- Polyamines promote the formation of the A beta peptide amyloid fibers that are a hallmark of Alzheimer's disease. Here we show that polyamines interact with nonaggregated A beta peptides, thereby reducing the peptide's hydrophobic surface. We characterized the associated conformational change through NMR titrations and molecular dynamics simulations. We found that even low concentrations of spermine, sperimidine, and putrescine fully protected SH-SY5Y (a neuronal cell model) against the most toxic conformational species of AA even at an A beta oligomer concentration that would otherwise kill half of the cells or even more. These observations lead us to conclude that polyamines interfere with the more toxic prefibrillar conformations and might protect cells by promoting the structural transition of A beta toward its less toxic fibrillar state that we reported previously. Since polyamines are present in brain fluid at the concentrations where we observed all these effects, their activity needs to be taken into account in understanding the molecular processes related to the development of Alzheimer's disease.
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| 8. |
- Luo, Jinghui, et al.
(författare)
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Inhibiting and Reversing Amyloid-β Peptide (1-40) Fibril Formation with Gramicidin S and Engineered Analogues
- 2013
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Ingår i: Chemistry - A European Journal. - : Wiley. - 0947-6539 .- 1521-3765. ; 19:51, s. 17338-17348
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Tidskriftsartikel (refereegranskat)abstract
- In Alzheimer's disease, amyloid-β (Aβ) peptides aggregate into extracellular fibrillar deposits. Although these deposits may not be the prime cause of the neurodegeneration that characterizes this disease, inhibition or dissolution of amyloid fibril formation by Aβ peptides is likely to affect its development. ThT fluorescence measurements and AFM images showed that the natural antibiotic gramicidin S significantly inhibited Aβ amyloid formation in vitro and could dissolve amyloids that had formed in the absence of the antibiotic. In silico docking suggested that gramicidin S, a cyclic decapeptide that adopts a β-sheet conformation, binds to the Aβ peptide hairpin-stacked fibril through β-sheet interactions. This may explain why gramicidin S reduces fibril formation. Analogues of gramicidin S were also tested. An analogue with a potency that was four-times higher than that of the natural product was identified.
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| 9. |
- Luo, Jinghui, et al.
(författare)
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Non-chaperone Proteins Can Inhibit Aggregation and Cytotoxicity of Alzheimer Amyloid beta Peptide
- 2014
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 289:40, s. 27766-27775
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Tidskriftsartikel (refereegranskat)abstract
- Background: A amyloid formation is associated with Alzheimer disease. Results: Non-chaperone proteins prevent amyloid formation and reduce the cytotoxicity of the A peptide. Conclusion: Non-chaperone proteins may affect the onset and development of Alzheimer disease by interfering with A peptide aggregation. Significance: Non-chaperone proteins can function as a chaperone protein to regulate the pathway of the A fibrillation in proteostasis providing a new strategy in the treatment of Alzheimer disease. Many factors are known to influence the oligomerization, fibrillation, and amyloid formation of the A peptide that is associated with Alzheimer disease. Other proteins that are present when A peptides deposit in vivo are likely to have an effect on these aggregation processes. To separate specific versus broad spectrum effects of proteins on A aggregation, we tested a series of proteins not reported to have chaperone activity: catalase, pyruvate kinase, albumin, lysozyme, -lactalbumin, and -lactoglobulin. All tested proteins suppressed the fibrillation of Alzheimer A(1-40) peptide at substoichiometric ratios, albeit some more effectively than others. All proteins bound non-specifically to A, stabilized its random coils, and reduced its cytotoxicity. Surprisingly, pyruvate kinase and catalase were at least as effective as known chaperones in inhibiting A aggregation. We propose general mechanisms for the broad-spectrum inhibition A fibrillation by proteins. The mechanisms we discuss are significant for prognostics and perhaps even for prevention and treatment of Alzheimer disease.
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| 10. |
- Neiß (Neiss), Michael, 1977-, et al.
(författare)
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3D laser scanning as a tool for Viking Age studies
- 2013
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Ingår i: Virtual archaeology: nondestructive methods of prospections, modeling, reconstructions: Proceedings of the First International Conference held at the State Hermitage Museum 4–6 June 2012 St. Petersburg, Russia. - St. Petersburg : The State Hermitage Publishers. - 9785935725167 ; , s. 170-184
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Three-dimensional (3D) laser scanners are becoming increasingly more affordable and user-friendly, making 3D-modeling tools more widely available to researchers in various countries and disciplines. In archaeology, 3D-modeling has the particular advantages of facilitating the documentation and analysis of objects that are fragile, rare, and often difficult to access. We have previously shown that 3D-modeling is a highly useful tool for shape analysis of archaeological bone material, due to the high measurement accuracy inherent in the latest generation of 3D laser scanners (Sholts et al. 2010; 2011). In this work, we explore the utility of 3D-modeling as a tool for Viking Age artefact analysis. To test the usefulness of 3D-modeling when analyzing artefacts with a very complex morphology, we chose highly ornate Viking Age baroque shaped brooches as study objects. These baroque shaped brooches constitute a group of dress ornaments mainly encountered in eastern Viking Age Scandinavia. Due to their large cast and/or attached bosses they obtain an almost baroque appearance, hence their name (cf. Jansson 1984: p. 81). They appear in two major versions, i.e. circular or equal armed, and in two kinds of material, i.e. silver- and copper-based alloys. Because of the position of bronze brooches in burial contexts, it appears they were used to fasten the cape or shawl in the female dress (cf. Jansson 1984: p. 75ff., Aagård 1984: p. 96ff.; Neiß 2006, figs. 3, 4; Capelle 1962: p. 106). For the present work a recently excavated brooch from Denmark was analyzed, together with three Russian brooches with nearly iconic status in the field of Viking Age studies. In the three case studies, we investigated possible uses of 3D-modeling for artefact analysis, artefact reconstruction, and tool mark and motif analysis. Exploring the usefulness of 3D-modeling for these purposes allowed us to draw conclusions regarding how 3D-analysis can be best incorporated into future artefact analysis. In addition, the case studies allowed us to gain new insights about the baroque shaped brooches and their uses.
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| 11. |
- Richman, Michal, et al.
(författare)
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In Vitro and Mechanistic Studies of an Antiamyloidogenic Self-Assembled Cyclic D,L-alpha-Peptide Architecture
- 2013
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Ingår i: Journal of the American Chemical Society. - : American Chemical Society (ACS). - 0002-7863 .- 1520-5126. ; 135:9, s. 3474-3484
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Tidskriftsartikel (refereegranskat)abstract
- Misfolding of the A beta protein and its subsequent aggregation into toxic oligomers are related to Alzheimer's disease. Although peptides of various sequences can self-assemble into amyloid structures, these structures share common three-dimensional features that may promote their cross-reaction. Given the significant similarities between amyloids and the architecture of self-assembled cyclic D,L-alpha-peptide, we hypothesized that the latter may bind and stabilize a nontoxic form of A beta thereby preventing its aggregation into toxic forms. By screening a focused library of six-residue cyclic D,L-alpha-peptides and optimizing the activity of a lead peptide, we found one cyclic D,L-alpha-peptide (CP-2) that interacts strongly with A beta and inhibits its aggregation. In transmission electron microscopy, optimized thioflavin T and cell survival assays, CP-2 inhibits the formation of A beta aggregates, entirely disassembles preformed aggregated and fibrillar A beta, and protects rat pheochromocytoma PC12 cells from A beta toxicity, without inducing any toxicity by itself. Using various immunoassays, circular dichroism spectroscopy, photoinduced cross-linking of unmodified proteins (PICUP) combined with SDS/PAGE, and NMR, we probed the mechanisms underlying CP-2's antiamyloidogenic activity. NMR spectroscopy indicates that CP-2 interacts with A beta through its self-assembled conformation and induces weak secondary structure in A beta. Upon coincubation, CP-2 changes the aggregation pathway of A beta and alters its oligomer distribution by stabilizing small oligomers (1-3 mers). Our results support studies suggesting that toxic early oligomeric states of A beta may be composed of antiparallel beta-peptide structures and that the interaction of A beta with CP-2 promotes formation of more benign parallel beta-structures. Further studies will show whether these kinds of abiotic cyclic D,L-alpha-peptides are also beneficial as an intervention in related in vivo models.
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| 12. |
- Sholts, Sabrina B., et al.
(författare)
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Brief Communication : Additional Cases of Maxillary Canine-First Premolar Transposition in Several Prehistoric Skeletal Assemblages From the Santa Barbara Channel Islands of California
- 2010
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Ingår i: American Journal of Physical Anthropology. - : Wiley. - 0002-9483 .- 1096-8644. ; 143:1, s. 155-160
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Tidskriftsartikel (refereegranskat)abstract
- This article identifies and discusses seven new cases of complete maxillary canine-premolar transposition in ancient populations from the Santa Barbara Channel region of California. A high frequency of this tooth transposition has been previously documented within a single prehistoric cemetery on one of the Channel Islands. A total of 966 crania representing 30 local sites and about 7,000 years of human occupation were examined, revealing an abnormally high prevalence of this transposition trait among islanders during the Early period of southern California prehistory (-,5500-600 B.C.). One of the affected crania is from a cemetery more than 7,000-years-old and constitutes the earliest case of tooth transposition in humans so far reported. The results are consistent with findings by other studies that have indicated inbreeding among the early Channel Islands groups. Together with the normal transposition rates among mainland populations, the decreasing prevalence of maxillary canine-first premolar transposition among island populations across the Holocene suggests that inbreeding on the northern Channel Islands had all but ceased by the end of the first millennium B.C., most likely as a result of increased cross-channel migration and interaction. Am J Phys Anthropol 143:155-160, 2010.
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| 13. |
- Sholts, Sabrina B., et al.
(författare)
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Flake scar patterns of Clovis points analyzed with a new digital morphometrics approach : evidence for direct transmission of technological knowledge across early North America
- 2012
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Ingår i: Journal of Archaeological Science. - : Elsevier BV. - 0305-4403 .- 1095-9238. ; 39:9, s. 3018-3026
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Tidskriftsartikel (refereegranskat)abstract
- Clovis points are the principal diagnostic artifacts of a Clovis complex that spread across North America between ca. 11,050-10,800 radiocarbon years before present. Clovis may be the best documented Paleoamerican culture in North America, but much remains to be learned about the movement and interactions of Clovis peoples. Similarities among Clovis points from geographically diverse locations have led some researchers to suggest that a uniform projectile point technology existed across North America during Clovis times. Others have rejected this idea, proposing local and independent technological adaptations to different regional environments. To investigate these ideas, we used digital morphometrics to analyze 50 Clovis points from nine different contexts. First, 3D surface models of the points were created with a portable laser scanner. Next, these models were digitally cross-sectioned through both faces, yielding two-dimensional isoheight contours of flake scar patterns that reflect the original reduction techniques used to shape the projectile points. In the final step, the contours were transformed with elliptic Fourier analysis into Fourier coefficient series, and patterns of variation and symmetry were explored with principal components analysis. When compared to modern Clovis point replicas made by an expert knapper, the flake scar contours of the ancient Clovis points showed little morphological variation and a large degree of bifacial symmetry. Our results support the existence of a widespread standardized Clovis knapping technique, most likely transmitted through direct interaction between knappers from different groups.
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| 14. |
- Sholts, Sabrina B., et al.
(författare)
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Identification of Group Affinity from Cross-sectional Contours of the Human Midfacial Skeleton Using Digital Morphometrics and 3D Laser Scanning Technology
- 2011
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Ingår i: Journal of Forensic Sciences. - : Wiley. - 0022-1198 .- 1556-4029. ; 56:2, s. 333-338
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Tidskriftsartikel (refereegranskat)abstract
- Identifying group affinity from human crania is a long-standing problem in forensic and physical anthropology. Many craniofacial differences used in forensic skeletal identification are difficult to quantify, although certain measurements of the midfacial skeleton have shown high predictive value for group classifications. This study presents a new method for analyzing midfacial shape variation between different geographic groups. Three-dimensional laser scan models of 90 crania from three populations were used to obtain cross-sectional midfacial contours defined by three standard craniometric landmarks. Elliptic Fourier transforms of the contours were used to extract Fourier coefficients for statistical analysis. After cross-validation, discriminant functions based on the Fourier coefficients provided an average of 86% correct classifications for crania from the three groups. The high rate of accuracy of this method indicates its usefulness for identifying group affinities among human skeletal remains and demonstrates the advantages of digital 3D model-based analysis in forensic research.
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| 15. |
- Sholts, Sabrina B., et al.
(författare)
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Variation in the Measurement of Cranial Volume and Surface Area Using 3D Laser Scanning Technology
- 2010
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Ingår i: Journal of Forensic Sciences. - : Wiley. - 0022-1198 .- 1556-4029. ; 55:4, s. 871-876
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional (3D) laser scanner models of human crania can be used for forensic facial reconstruction, and for obtaining craniometric data useful for estimating age, sex, and population affinity of unidentified human remains. However, the use of computer-generated measurements in a casework setting requires the measurement precision to be known. Here, we assess the repeatability and precision of cranial volume and surface area measurements using 3D laser scanner models created by different operators using different protocols for collecting and processing data. We report intraobserver measurement errors of 0.2% and interobserver errors of 2% of the total area and volume values, suggesting that observer-related errors do not pose major obstacles for sharing, combining, or comparing such measurements. Nevertheless, as no standardized procedure exists for area or volume measurements from 3D models, it is imperative to report the scanning and postscanning protocols employed when such measurements are conducted in a forensic setting.
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| 16. |
- Taqi, Malik Mumtaz, et al.
(författare)
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Conformation Effects of CpG Methylation on Single-Stranded DNA Oligonucleotides : Analysis of the Opioid Peptide Dynorphin-Coding Sequences
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:6, s. e39605-
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Tidskriftsartikel (refereegranskat)abstract
- Single-stranded DNA (ssDNA) is characterized by high conformational flexibility that allows these molecules to adopt a variety of conformations. Here we used native polyacrylamide gel electrophoresis (PAGE), circular dichroism (CD) spectroscopy and nuclear magnetic resonance (NMR) spectroscopy to show that cytosine methylation at CpG sites affects the conformational flexibility of short ssDNA molecules. The CpG containing 37-nucleotide PDYN (prodynorphin) fragments were used as model molecules. The presence of secondary DNA structures was evident from differences in oligonucleotide mobilities on PAGE, from CD spectra, and from formation of A-T, G-C, and non-canonical G-T base pairs observed by NMR spectroscopy. The oligonucleotides displayed secondary structures at 4 degrees C, and some also at 37 degrees C. Methylation at CpG sites prompted sequence-dependent formation of novel conformations, or shifted the equilibrium between different existing ssDNA conformations. The effects of methylation on gel mobility and base pairing were comparable in strength to the effects induced by point mutations in the DNA sequences. The conformational effects of methylation may be relevant for epigenetic regulatory events in a chromatin context, including DNA-protein or DNA-DNA recognition in the course of gene transcription, and DNA replication and recombination when double-stranded DNA is unwinded to ssDNA.
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| 17. |
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| 18. |
- Wärmländer, Sebastian K. T. S., et al.
(författare)
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Could the Health Decline of Prehistoric California Indians be Related to Exposure to Polycyclic Aromatic Hydrocarbons (PAHs) from Natural Bitumen?
- 2011
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Ingår i: Journal of Environmental Health Perspectives. - : Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 119:9, s. 1203-1207
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The negative health effects of polycyclic aromatic hydrocarbons (PAHs) are well established for modern human populations but have so far not been studied in prehistoric contexts. PAHs are the main component of fossil bitumen, a naturally occurring material used by past societies such as the Chumash Indians in California as an adhesive, as a waterproofing agent, and for medicinal purposes. The rich archaeological and ethnohistoric record of the coastal Chumash suggests that they were exposed to multiple uptake pathways of bituminous PAHs, including direct contact, fume inhalation, and oral uptake from contaminated water and seafood. OBJECTIVES: We investigated the possibility that PAHs from natural bitumen compromised the health of the prehistoric Chumash Indians in California. CONCLUSIONS: Exposure of the ancient Chumash Indians to toxic PAHs appears to have gradually increased across a period of 7,500 years because of an increased use of bitumen in the Chumash technology, together with a dietary shift toward PAH-contaminated marine food. Skeletal analysis indicates a concurrent population health decline that may be related to PAH uptake. However, establishing such a connection is virtually impossible without knowing the actual exposure levels experienced by these populations. Future methodological research may provide techniques for determining PAH levels in ancient skeletal material, which would open new avenues for research on the health of prehistoric populations and on the long-term effects of human PAH exposure.
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| 19. |
- Wärmländer, Sebastian K. T. S., et al.
(författare)
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Metallurgical findings from a Viking Age chieftain's farm in Iceland
- 2010
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Ingår i: Journal of Archaeological Science. - : Elsevier BV. - 0305-4403 .- 1095-9238. ; 37:9, s. 2284-2290
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Tidskriftsartikel (refereegranskat)abstract
- The metalworking, metal import, and use of metal in medieval Iceland is still little understood. When the Scandinavian settlers colonized Iceland in the 9th c. AD, the island was found to contain no useful metal deposits save for bog iron, and the deforestation that followed the settlement resulted in a scarcity of wood. Only in the last decades have archaeological excavations begun to unravel how the first Icelanders dealt with this lack of resources. This paper presents the metallurgical findings from a Viking Age chieftain's farmstead at Hrisbru in the Mosfell valley, located just outside Iceland's present-day capital Reykjavik. The excavated metal objects had all been crafted with good workmanship employing technology similar to that used in mainland Scandinavia. However, most excavated metal finds show evidence of re-use, which together with the second-grade metal in some of the objects indicates a shortage of raw material that prompted the Icelandic colonizers to improvise and make do with whatever material was at hand. Even though this chieftain's farm was materially poorer than contemporaneous high-status farms in mainland Scandinavia, it was wealthy by Icelandic standards. The analytical results show that some excavated objects were imported trade goods deriving from both neighboring and far-away localities, proving that the farm was part of the extensive trade network of the Viking world. Most likely, this farm represents the upper limit to what a Viking Age farm in Iceland could afford in terms of material objects and trade goods.
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| 20. |
- Wärmländer, Sebastian K. T. S., et al.
(författare)
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Sampling and statistical considerations for the Suchey-Brooks method for pubic bone age estimation : Implications for regional comparisons
- 2011
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Ingår i: Science & justice. - : Elsevier BV. - 1355-0306 .- 1876-4452. ; 51:3, s. 131-134
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Tidskriftsartikel (refereegranskat)abstract
- Although the Suchey-Brooks (SB) system is currently the most widely used method for age-at-death estimation from the pubic bone, the system continues to evolve through stepwise improvements. Since the system was developed from a pubic bone sample derived mainly from North Americans, it is unclear how well it performs on populations from other continents. During the last decade, studies of the SB system on pubic bone samples from local populations in Europe and Asia have indicated regional differences in the relationship between age and pubic bone development. However, these studies have for the most part followed different research protocols, which make comparisons between their results less meaningful. It would be most useful if future regional analysis of the SB system were done in a rigorous and uniform fashion, following standard procedures. In this paper, sampling and statistical considerations are outlined that hopefully will help to standardize research on the SB system.
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