An elemental analysis of archaeological bone from Sicily as a test of predictability of diagenetic change

Cortical human bone samples from three tightly dated components of a single Sicilian site were chemically analyzed employing the highly sensitive technique of inductively coupled plasma emission spectroscopy. Although the skeletons appeared to be excellently preserved, significant diagenesis was detected. Moreover, a majority of the elements tested showed no constant or linear variation over time, implying that diagenetic change tends not to be a predictable function of duration of interment. Variation among major long bones of a single skeleton was quite high, as was variation across the cortex. The latter may reflect chemical inhomogeneity in bone tissue or may be an artifact of postmortem change. The results demonstrate the hazards of unsuspected and unpredictable diagenesis, which must be controlled before reliable dietary inferences can be drawn.     

Investigation of elemental content distribution in femoral head slice with osteoporosis by SRXRF microprobe

A synchrotron radiation X-ray fluorescence microprobe analysis technique was used to scan a slice of the femoral head from its periphery to its center, via cartilage, compact, and spongy zones in order to determine the distribution and the way inorganic substances are lost in bone tissue. The sample preparation and experimental apparatus are described in detail. The quantitative computerized tomography of elemental distribution, such as Ca, P, K, Fe, Zn, Sr, and Pb in bone slice tissue, including cartilage, substantial compact, and substantial spongy, is investigated. Combined with the correlation among, P, K, Zn, Sr, and Ca, the route of loss of minerals and the physiological functions of some metal elements in bone are also discussed.     

Exploring ocean biogeochemistry by single-cell microprobe analysis of protist elemental composition

The biogeochemical cycles of many elements in the ocean are linked by their simultaneous incorporation into protists. In order to understand these elemental interactions and their implications for global biogeochemical cycles, accurate measures of cellular element stoichiometries are needed. Bulk analysis of size-fractionated particulate material obscures the unique biogeochemical roles of different functional groups such as diatoms, calcifying protists, and diazotrophs. Elemental analysis of individual protist cells can be performed using electron, proton, and synchrotron X-ray microprobes. Here we review the capabilities and limitations of each approach and the application of these advanced techniques to cells collected from natural communities. Particular attention is paid to recent studies of plankton biogeochemistry in low-iron waters of the Southern Ocean. Single-cell analyses have revealed significant inter-taxa differences in phosphorus, iron, and nickel quotas. Differences in the response of autotrophs and heterotrophs to iron fertilization were also observed. Two-dimensional sub-cellular mapping indicates the importance of iron to photosynthetic machinery and of zinc to nuclear organelles. Observed changes in diatom silicification and cytoplasm content following iron fertilization modify our understanding of the relationship between iron availability and silicification. These examples demonstrate the advantages of studying ocean biogeochemistry at the level of individual cells.     

Electron microprobe X-ray analysis of polyphosphate granules in Plesiomonas shigelloides

Electron-dense inclusion bodies were found in most Plesiomonas shigelloides cells, regardless of the incubation time. At the 4-hr incubation period, the size of inclusion bodies was distributed in the range of 50 to 150 nm in diameter, and at the logarithmic phase of growth it increased up to a size visible by light microscope. By an electron microprobe X-ray analysis, phosphorus, potassium, and magnesium were detected in the inclusion bodies which confirms the assumption of Pastian and Bromel (Appl. Environ. Microbiol. 47: 216 (1984] that the inclusion bodies have a very similar elemental composition to the polyphosphate granules of C. diphtheriae.     

The biomechanics of human femurs in axial and torsional loading: comparison of finite element analysis, human cadaveric femurs, and synthetic femurs

To assess the performance of femoral orthopedic implants, they are often attached to cadaveric femurs, and biomechanical testing is performed. To identify areas of high stress, stress shielding, and to facilitate implant redesign, these tests are often accompanied by finite element (FE) models of the bone/implant system. However, cadaveric bone suffers from wide specimen to specimen variability both in terms of bone geometry and mechanical properties, making it virtually impossible for experimental results to be reproduced. An alternative approach is to utilize synthetic femurs of standardized geometry, having material behavior approximating that of human bone, but with very small specimen to specimen variability. This approach allows for repeatable experimental results and a standard geometry for use in accompanying FE models. While the synthetic bones appear to be of appropriate geometry to simulate bone mechanical behavior, it has not, however, been established what bone quality they most resemble, i.e., osteoporotic or osteopenic versus healthy bone. Furthermore, it is also of interest to determine whether FE models of synthetic bones, with appropriate adjustments in input material properties or geometric size, could be used to simulate the mechanical behavior of a wider range of bone quality and size. To shed light on these questions, the axial and torsional stiffness of cadaveric femurs were compared to those measured on synthetic femurs. A FE model, previously validated by the authors to represent the geometry of a synthetic femur, was then used with a range of input material properties and change in geometric size, to establish whether cadaveric results could be simulated. Axial and torsional stiffnesses and rigidities were measured for 25 human cadaveric femurs (simulating poor bone stock) and three synthetic "third generation composite" femurs (3GCF) (simulating normal healthy bone stock) in the midstance orientation. The measured results were compared, under identical loading conditions, to those predicted by a previously validated three-dimensional finite element model of the 3GCF at a variety of Young's modulus values. A smaller FE model of the 3GCF was also created to examine the effects of a simple change in bone size. The 3GCF was found to be significantly stiffer (2.3 times in torsional loading, 1.7 times in axial loading) than the presently utilized cadaveric samples. Nevertheless, the FE model was able to successfully simulate both the behavior of the 3GCF, and a wide range of cadaveric bone data scatter by an appropriate adjustment of Young's modulus or geometric size. The synthetic femur had a significantly higher stiffness than the cadaveric bone samples. The finite element model provided a good estimate of upper and lower bounds for the axial and torsional stiffness of human femurs because it was effective at reproducing the geometric properties of a femur. Cadaveric bone experiments can be used to calibrate FE models' input material properties so that bones of varying quality can be simulated.     

Fate of elemental sulfur in an intertidal sediment

Abstract: Sediment from a tidal flat at Wedderwarden, near the mouth of the Weser estuary, northern Germany, was amended with elemental sulfur, and concentrations of metabolic end products were monitored. The production of both sulfate and sulfide was consistent with disproportionation as the most important fate of the added elemental sulfur. A population of bacteria conducting active elemental sulfur disproportionation was also enriched from the sediment. In the enrichments, containing both elemental sulfur and Fe oxides as a sulfide 'scrub', sulfide and sulfate were produced in a ratio of     , somewhat lower than the predicted ratio of     . The mismatch between predicted and observed production ratios is explained by the channelling of electrons into autotrophic or mixotrophic CO₂ fixation rather than sulfide formation. The production of organic carbon, in the correct amount to explain the observed sulfide to sulfate production ratio, was verified by organic carbon analysis. Finally, rates of sulfate reduction were identical in the elemental sulfur amended sediment, and in control sediment with no added sulfur. Hence, the heterotrophic bacterial community was completely unaffected by an active metabolism conducting elemental sulfur disproportionation.     

Electron microprobe analysis into interactions of a resin-modified glass-ionomer cement and a modified composite with human dentin in vitro

When materials used in restorative dentistry, such as a glass-ionomer cement or a compomer, were applied to dentin, ion exchanges occur between the material and the dentin. This work is based on an assessment in vitro of the ion exchanges occurring over time between (i) a glass-ionomer cement and dentin and (ii) a compomer and dentin. An electron microprobe analysis, technique not previously used for such a study, permitted qualitative and quantitative analysis of the interface and of the peripheral dentin. Analysis of the distribution of the elements in the interface and nearby showed continuous, progressive exchanges between the glass-ionomer cement and the dentin and absence of diffusion between the compomer and the dentin.     

Electron microscopic microprobe analysis of mineralized collagen fibrils and extracollagenous regions in Turkey leg tendon

Summary Bundles of tibia tendon from 19 week-old turkeys were deep frozen, freeze dried and embedded in styrol methacrylate or Epon. In the distal mineralized region, bundles of unmineralized collagen fibrils as well as mineralized regions consisting of round microcompartments with low contrast surrounded by a mineral sheath with high contrast were found. The inner regions with low contrast corresponded to the mineralized collagen fibrils, while the contrast-rich peripheral zones corresponded to the mineralized collagen-free ground substance. Using electron microscopic microprobe analysis, it was shown that the peripheral mineralized region, consisting mainly of closely packed needles, often contained 100% more mineral substance than the central, mineralized collagen zone, which consisted mainly of plate-like crystallites. Possible reasons for this difference in mineral content are discussed on the molecular level.The authors would like to express their gratitude to the Deutsche Forschungsgemeinschaft for financial support and to Fräulein Christine Dörnen for valuable technical assistance     

Electron backscatter diffraction (EBSD) as a tool for detection of coral diagenesis

Fine-scale structures of intact modern and fossil coralline skeletons were analysed to determine alteration to secondary cements and phases using electron backscatter diffraction (EBSD). EBSD analysis revealed secondary aragonite cements in endolithic borings in the modern skeleton and whole dissepiments of the fossil skeleton replaced by calcite, despite X-ray diffraction (XRD) bulk analysis of the general area suggesting only aragonite was present. Non-destructive, in situ screening of coral samples by EBSD analysis provides a valuable tool for assessing the extent of alteration and can determine which areas may produce more reliable climate proxy data. Communicated by Geology Editor Dr. Bernhard Riegl     

The human skeletons of herculaneum

Skeletons of 139 Herculaneans trapped by the vulcanic eruption of Mt. Vesuvius in A.D. 79 were studied by observation, measurement and chemical analysis. A cross section of the population suggests that reproduction may not have been sufficient to maintain population numbers, a hypothesis corroborated by parity statistics as well as contemporaty literature. In general, this population had excellent teeth with few lesions and edge-bite occlusion. Twenty-seven percent had some degree of hypoplastic lines in the dental enamel, suggesting that childhood illnesses were common. The ancient population was taller than modern Neopolitans, but shorter than modern Americans. Also, their children grew at a slower rate than Americans of the same ages. Biochemical analysis suggests that their diet was more dependent on sea fish than on red meat. Lead analysis shows slightly higher values for the adult male population than for the females. Some degree of arthritis was apparent in 42% of the population. Traumata occurred to 22.7% of these people. Signs of healed anemia in any degree are present in 34.1%; etiology could have been nutritional deficiency or heterozygotic thalassemia. Two individuals and their pathologies are presented: one case of congenital bilateral hip dysplasia and the other of healed rickets.     

Electron microprobe analysis of juvenile walleye pollock,Theragra chalcogramma,otoliths from Alaska: a pilot stock separation study

Synopsis The incorporation of dissolved oceanic constituents in the otoliths of fish has potential as a chemical tracer for reconstructing the early life history of marine fish. Wavelength dispersive spectrometers on an electron microprobe were used to measure Na, Mg, P, S, Cl, K, Ca, and Sr concentrations on the outer margins of 57 juvenile walleye pollock, Theragra chalcogramma, otoliths from five locations in the Gulf of Alaska and Bering Sea. Discriminant analyses that used various combinations of Na, P, K, Sr, and fish standard length and/or age showed that 60–80% of the samples could be assigned to the correct capture locality. While the concentrations of some of the measured elements correlated with standard length or age of the fish, there are measurable differences among localities when concentrations are length or age corrected, mainly due to differences in Na and K concentrations. Elemental composition of otoliths potentially could be used to assign fish from a mixed stock fishery to original stocks, information that is greatly needed for the effective management of fish stocks.     

Palaeopathology and genes: Investigating the genetics of infectious diseases in excavated human skeletal remains and mummies from past populations

The aim of this paper is to review the use of genetics in palaeomicrobiology, and to highlight the importance of understanding past diseases. Palaeomicrobiology is the study of disease pathogens in skeletal and mummified remains from archaeological contexts. It has revolutionarised our understanding of health in the past by enabling a deeper knowledge of the origins and evolution of many diseases that have shaped us as a species. Bacterial diseases explored include tuberculosis, leprosy, bubonic plague, typhoid, syphilis, endemic and epidemic typhus, trench fever, and Helicobacter pylori. Viral diseases discussed include influenza, hepatitis B, human papilloma virus (HPV), human T-cell lymphotrophic virus (HTLV-1) and human immunodeficiency virus (HIV). Parasitic diseases investigated include malaria, leishmaniasis, Chagas' disease, roundworm, whipworm, pinworm, Chinese liver fluke, fleas and lice. Through a better understanding of disease origins and their evolution, we can place into context how many infectious diseases are changing over time, and so help us estimate how they may change in the future.     

Immunocytochemical analysis of apoprotein E distribution in human tissues

Localization of apoprotein E (apo E) has been studied in different human tissues. For this aim the immunoperoxidase method and peroxidase-antiperoxidase complex, polyclonal and monoclonal antibodies, to apo E have been used. In every human tissue analysed apo E-containing cells have been revealed. To the latter the following cell types belong: hepatocytes and hepatic sinusoidal cells, macrophages of the spleen, lymph nodes and pulmonary tissues, glial cells and cells in all layers of the adrenals, skin keratinocytes, cells of the glomerular capsule and convoluted tubules of the kidney, spermatocytes and smooth muscle cells of the testis. Besides, apo E is revealed in endothelium of some vessels. As demonstrate the results obtained, apo E is found practically in all human tissues. A suggestion is made that besides its participation in reverse cholesterol transport, this protein performs a number of additional functions, such as regulation of local hormonal homeostasis of an organ.     

Electron microbeam analysis of calcium distribution in the ciliated protozoan, Spirostomum ambiguum.

Electron microprobe analyses of calcium distribution in the ciliated protozoan, Spirostomum ambiguum, indicated several calcium rich sites. One site was an endoplasmic distribution of calcium coincident with phosphorus which corroborates previous findings of hydroxyapatite deposits within Spirostomum. These apatite deposits were distributed throughout the endoplasm, but not within the nuclei or the contractile vacuole. Calcium was also detected within the cortical region. Cortical calcium was in greater concentration in the anterior portion of the organism and decreased towards the posterior end (region containing the contractile vacuole). Phosphorus and potassium were also detected as gradients from the anterior end, whereas magnesium was detected in the same density throughout the cortical region. Line scans of cortical regions suggested (1) distributions of calcium within mitochondria and/or vesicles, and (2) calcium associated with bundles of microfilaments.     

Cellular cadmium distribution in the common winkle,Littorina littorea (L.) determined by X-ray microprobe analysis and histochemistry

Summary Various tissues of common winkles,Littorina littorea (L.), experimentally exposed to cadmium (Cd) chloride were examined using light and electron microscopy and their elemental composition determined by X-ray microanalysis and histochemistry. Membrane granules in gill epithelial cells with paddle cilia contain carbonates, phosphates and sulphides associated with different cations in different types of granules. Traces of Cd have been found only in those granules containing sulphur and iron. Nephrocytes also contain small amounts of this metal in the cytoplasm of excretory cells. X-ray microanalysis reveals that concretions of basophilic cells are minor sites for Cd sequestration while BTAN-ASSG stain for unbound Cd indicates that most of the Cd is located within the lysosomes of digestive cells in association with proteins. Low amounts of the metal have been evidenced in the granules of epithelial mantle cells rich in sulphur. The results also indicate that hemocytes contain granules of calcium phosphate and iron sulphide. Cd is also associated to sulphur rather than to phosphate. These hemocytes may act as Cd carrier from gills to kidney and digestive gland. A hypothetical pathway for Cd accumulation and detoxification is suggested.