1,720,967 research outputs found
Confocal Laser Scanning Microscopy: A Flexible Tool For Simultaneous Polarization And Three-Dimensional Fluorescence Imaging Of Archaeological Compact Bone
No full textWide-field polarized light and epifluorescence microscopy have been used to enhance analysis of archaeological bone tissue, providing information on bone formation, modeling, pathology, preservation, age estimation, and biomechanics. Though valuable, these techniques are limited by their inability to remove out-of-focus light and view multiple levels of a sample, restricting our understanding of the three-dimensional (3-D) microarchitecture of compact bone. Modern technological advances, such as microscopic computerized tomography, allow increasing resolution in 3-D bone imaging, but do not allow fluorescence labeling or polarized-light analysis. Confocal laser scanning microscopy (CLSM) is a valuable tool for 3-D histology. However, its application to the study of compact bone is lacking, especially in archaeological and forensic sciences. The current study investigated CLSM as a tool for fluorescence and polarized-light microscopy of archaeological compact bone in order to demonstrate its advantages. Standard techniques and CLSM are compared in their suitability for imaging well preserved archaeological bones from the Dakhleh Oasis, Egypt. CLSM\u27s high resolution, multi-channel, two- and three-dimensional capabilities augment the flexibility and creativity of compact bone imaging and have the potential to increase the accuracy of quantitative medical and anthropological histomorphometric techniques. CLSM is specifically suggested as a useful tool for the investigation of ancient bone fluorescence caused by the presence of tetracycline and/or other fluorochromes. © 2009 Elsevier Ltd. All rights reserved
Spectral And Photobleaching Analysis Using Confocal Laser Scanning Microscopy: A Comparison Of Modern And Archaeological Bone Fluorescence
No full textSince the 1950s, tetracycline (TC) administration has been used to create fluorescent \u27labels\u27 in bone for histomorphometric analysis. Similar fluorescence discovered in ancient human bone from Egypt and Sudan has been attributed to bacterially contaminated food-stores. It has been suggested that TC from this source could have affected the health of exposed ancient populations. However, no efficient means for the quantitative comparison of fluorescent labels within or between individuals or populations has been proposed. In the current study, confocal laser scanning microscopy (CLSM) was shown to be an effective tool for fluorescence detection and spectral analysis in bone. Well-preserved archaeological bone recovered from the Dakhleh Oasis, Egypt was compared to modern pig bone labeled with tetracycline and stained decalcified dog bone. TC fluorescence, whether archaeological or modern, was accurately identifiable by its spectrum. Photobleaching experiments suggest some difference exists in the photoresilience of archaeological and modern TC labels and that scans of one plane and area of focus can be made for more than an hour without complete loss of signal intensity. Results encourage the use of CLSM imaging and spectral analysis for further study on the nature of fluorescence in ancient and modern bone. © 2006 Elsevier Ltd. All rights reserved
Identification of a distinct histomorphological feature of long bones: Potential applications in paleopathology and bioarchaeology.
No full textIdentification of a distinct histomorphological feature of long bones: Potential applications in paleopathology and bioarchaeology.
No full textTwo perspectives on occupational activity patterns: do examinations of entheses and cross-sectional data result in similar physical activity reconstructions?
No full textTwo perspectives on occupational activity patterns: do examinations of entheses and cross-sectional data result in similar physical activity reconstructions?
No full textCross‐sectional analysis of long bones, occupational activities and long‐distance trade of the Classic Maya from Xcambó—Archaeological and osteological evidence
No full textXcambo is a Classic period Maya site (250-700 AD) situated on the northern coast of Yucatan, Mexico. Archaeological evidence suggests that the site began as a salt production center but adopted a more administrative role as a commercial port in the Late Classic period. Economic growth, depending on its magnitude, could have affected the daily occupations of Xcambo's inhabitants. However, this is difficult to infer from the archaeological record. The aim of this study was to directly evaluate this possibility through skeletal analysis. Since diaphyseal robusticity and shape are predominantly influenced by mechanical loading history, long bone cross-sections can be used to access activity patterns. To this end, humeri and femora of 47 male and 35 female adult specimens from two Xcambo population samples were scrutinized. Our analysis satisfies general archaeological expectations and provides additional information on the population's physical response to economic growth. Decreasing robusticity and femoral anterior-posterior rigidity indicate an overall decrease in physical workload and mobility, concomitant with the site's increasing administrative function. We also observed a significant decrease in sexual dimorphism, possibly attributable to the differential response of male and female physical work spheres during socioeconomic change. In general, our findings suggest even nonsubsistence based socioeconomic change can significantly affect the bone structure of a population, rendering activity analysis an important aspect of the reconstruction of living conditions of past populations
A distinct region of microarchitectural variation in femoral compact bone: Histomorphology of the endosteal lamellar pocket
No full textBone is a dynamic tissue, responding locally to differential mechanical loading and systemically to hormonal stimuli. Although the tendency is to consider compact bone a homogenous tissue, regional variations in microarchitecture are known to have quite different properties relating to processes of growth and mechanical loading. Specifically, we investigated an example of microstructural variation of the human, adult femoral endocortex, referred to here as the endosteal lamellar pocket (ELP). The femoral ELP is characterised as a histomorphological meta-feature, made distinct from general circumferential lamellae by its hemicircumferential lamellar orientation, medial positioning, radially oriented Volkmann's canals and decreased presence of Haversian systems. Our preliminary observations of mid-diaphyseal transverse thin-ground sections demonstrate the ELP as a regular meta-feature of adult human femora unearthed from the Maya archaeological site of Xcambo, Mexico. ELPs were easily identified in 38 of 45 examined individuals. Their size, shape and degree of secondary remodelling were variable. In comparison, ELP lamellae and those originating from the periosteum are divergent, or non-concentric in orientation. This divergence, along with the ELP's medial position, suggest it forms during growth through endosteal modelling drift. Possible considerations for ELP formation and persistence with age are discussed as well as its implications for the study of bone dynamics during growth and activity. Further research is necessary to quantitatively measure the morphology of ELPs and to identify any co-variance between ELP characteristics and age, sex or indicators of mechanical loading. Copyright (c) 2010 John Wiley & Sons, Ltd
Ancient antibiotics : tetracycline in human and animal bone from the Dakhleh Oasis, Egypt
Get PDFTwo decades ago archaeologists in northern Africa discovered evidence that an antibiotic was somehow included in diet of ancient peoples, possibly affecting the health of the population. It has been proposed that the causative organisms are Streptomyces aureofaciens - ubiquitous, mold-like, tetracycline-producing bacteria that could have contaminated grain products. Upon consumption, tetracyclines are incorporated into developing or remodeling bone, remaining observable under ultraviolet light for thousands of years. The current project focuses on an analysis of Roman-Egyptian human and animal bone from the Dakhleh Oasis in southwestern Egypt (100 BC to AD 360). Confocal Laser Scanning Microscopy (CLSM) is used to determine whether or not the population had been exposed to antibiotics, taking advantage of tetracycline\u27s natural fluorescent properties. Results show that, though nearly every sample shows tetracycline fluorescence described in previous literature, bone from the Kellis I and Kellis 2 cemeteries display distinct differences in florescent patterning. CLSM allows three dimensional viewing and high-resolution imaging, lending new perspective and increased accuracy to the analysis. Previously published theories regarding the means of exposure and resulting health affects are reconsidered. Further investigation could have implications that overflow their archaeological context due to the multiple uses modem science has for tetracycline therapy
Confocal Laser Scanning Microscopy As A Tool For The Investigation Of Tetracycline Fluorescence In Archaeologicalhuman Bone
Get PDFFluorochromes such as tetracycline have been used to label bone for histomorphometric analysis, measuring bone formation, growth, maintenance, and pathology. More recently, similar fluorescence has been observed in ancient human bone. Attributed to tetracycline (TC) exposure, this phenomenon could affect various aspects of health during life and/or preservation of remains postmortem. Standard epifluorescence microscopy is the most common tool employed in the analysis of these labels. Though valuable, this technique is limited by its inability to penetrate bone three-dimensionally and its inclusion of out-of-focus light, possibly disrupting accurate analysis. Confocal Laser Scanning Microscopy (CLSM) has been demonstrated as a valuable tool for three-dimensional histology. Its application to the study of compact bone fluorescence has been lacking, especially in archaeological and forensic sciences. In the following two papers, modern TC-controlled bone is compared to well preserved archaeological bone recovered from the Dakhleh Oasis, Egypt, using both standard wide-field and more modern confocal techniques for imaging and analysis. Spectral analysis via CLSM shows that both modern and ancient fluorescent labels in bone share the exact same fluorescence emission peak at 525 nm. Differences in the shape of the spectral curve and photobleaching characteristics are discussed. In addition, CLSM\u27s high-resolution two- and three-dimensional imaging capabilities (in polarized light, scattered light, and fluorescence light) are found to increase the flexibility and creativity of investigations into the occurrence of tetracycline labels in archaeological bone and could have added benefits for modern medical and anatomical experimentation
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