Clinical perspectives on secular trends of intervertebral foramen diameters in an industrialized European society

Low back pain origins have been a matter of great controversy. While spinal stenosis is now radiologically traceable, the alteration of intervertebral foramen is less clear. The aim of this study was to assess "secular trends” — alterations occurring from one generation to the next — in osseous intervertebral foramina of the major vertebral segments in an industrialized society, and to discuss their possible clinical implication. The macerated "maximum intervertebral foramen width” and "intervertebral foramen height” of all major vertebral levels in 71 nonpathologic Swiss adult skeletons from the nineteenth and early twentieth century, with known individual age and sex and similar geographic and socio-economic background, were measured by sliding caliper at validated landmarks. A secular trend of the increase in "maximum intervertebral foramen width” is found for most levels, with females showing a more prominent alteration. Additionally, the non-pathologic "maximum intervertebral foramen width” does not change with respect to individual age, nor is a significant side difference detectable. "Intervertebral foramen height,” hereby defined as the difference of the dorsal vertebral body height minus pedicle height, demonstrates for most levels, and either sex, an insignificant negative secular trend. Neither stature nor skeletal robustness vary significantly through time within this particular sample. The results of this study, despite obvious inadequacies of methods used, exclude secular narrowing of the "maximum intervertebral foramen width” as the only cause of radiculopathy or spinal stenosis. Furthermore, we found a mild insignificant decrease of the clinically more relevant "intervertebral foramen height.” Nevertheless, the detected short-time variability of the bony intervertebral foramen, independent of individual stature, skeletal robustness or age, argues for an enhanced focus on the understanding of clinically relevant changes of spinal morphology from generation to generatio

X-ray absorption-based imaging and its limitations in the differentiation of ancient mummified tissue

Objectives: Differentiation of ancient tissues is of key importance in the study of paleopathology and in the evolution of human diseases. Currently, the number of imaging facilities for the non-destructive discrimination of dehydrated tissue is limited, and little is known about the role that emerging imaging technologies may play in this field. Therefore, this study investigated the feasibility and quality of dual-energy computed tomography (DECT) for the discrimination of dry and brittle soft tissue. Moreover, this study explored the relationship between morphological changes and image contrast in ancient tissue by using X-ray micro-tomography (micro-CT). Materials and Methods: An Egyptian mummy head and neck was scanned with DECT at tube voltage/current of 140kVp/27mAs (tube A) and 100kVp/120mAs (tube B). The CT attenuation was determined by regions of interest (ROI) measurements of hard and soft tissue of the mummy skull. Finally, two samples from the posterior neck were dissected to acquire micro-CT images of shrunken dehydrated tissue. Results: Dual-energy CT images demonstrated the high contrast resolution of surface structures from mummy skull. Bone density changes in the posterior skull base as well as soft-tissue alterations of the eyes and tongue were assessed. Micro-CT scans allowed the identification of morphological changes and the discrimination of muscle tissue from inorganic material in samples taken from the neck. Conclusions: Significant attenuation differences (p < 0.0007) were observed within 12 of the 15 ancient tissue groups and organic materials using DECT. We detected a correlation between X-ray scattering and image contrast reduction in dehydrated tissue with micro-CT imagin

False positives complicate ancient pathogen identifications using high-throughput shotgun sequencing

Background: Identification of historic pathogens is challenging since false positives and negatives are a serious risk. Environmental non-pathogenic contaminants are ubiquitous. Furthermore, public genetic databases contain limited information regarding these species. High-throughput sequencing may help reliably detect and identify historic pathogens. Results: We shotgun-sequenced 8 16th-century Mixtec individuals from the site of Teposcolula Yucundaa (Oaxaca, Mexico) who are reported to have died from the huey cocoliztli (‘Great Pestilence’ in Nahautl), an unknown disease that decimated native Mexican populations during the Spanish colonial period, in order to identify the pathogen. Comparison of these sequences with those deriving from the surrounding soil and from 4 precontact individuals from the site found a wide variety of contaminant organisms that confounded analyses. Without the comparative sequence data from the precontact individuals and soil, false positives for Yersinia pestis and rickettsiosis could have been reported. Conclusions: False positives and negatives remain problematic in ancient DNA analyses despite the application of high-throughput sequencing. Our results suggest that several studies claiming the discovery of ancient pathogens may need further verification. Additionally, true single molecule sequencing’s short read lengths, inability to sequence through DNA lesions, and limited ancient-DNA-specific technical development hinder its application to palaeopathology

Evolutionary perspectives, heterogeneity and ovarian cancer: a complicated tale from past to present

Ovarian cancer is composed of a complex system of cells best described by features such as clonal evolution, spatial and temporal genetic heterogeneity, and development of drug resistance, thus making it the most lethal gynecologic cancer. Seminal work on cancer as an evolutionary process has a long history; however, recent cost-effective large-scale molecular profiling has started to provide novel insights coupled with the development of mathematical algorithms. In the current review, we have systematically searched for articles that focused on the clonal evolution of ovarian cancer to offer the whole landscape of research that has been done and highlight future research avenues given its characteristic features and connections to evolutionary biology. Keywords: Clonal evolution; Ovarian cancer; Spatial heterogeneity; Survival; Temporal heterogeneit