83 research outputs found
Tuberculosis-like respiratory infection in 245-million-year-old marine reptile suggested by bone pathologies
An absence of ancient archaeological and palaeontological evidence of pneumonia contrasts with its recognition in the more recent archaeological record. We document an apparent infection-mediated periosteal reaction affecting the dorsal ribs in a Middle Triassic eosauropterygian historically referred to as ‘Proneusticosaurus’ silesiacus. Highresolution X-ray microtomography and histological studies of the pathologically altered ribs revealed the presence of a continuous solid periosteal reaction with multiple superficial blebs (protrusions) on the visceral surfaces of several ribs. Increased vascularization and uneven lines of arrested growth document that the pathology was the result of a multiseasonal disease. While visceral surface localization of this periosteal reaction represents the earliest identified evidence for pneumonia, the blebs may have an additional implication: they have only been previously recognized in humans with tuberculosis (TB). Along with this diagnosis is the presence of focal vertebral erosions, parsimoniously compared to vertebral manifestation of TB in humans
The oldest record of aquatic amniote congenital scoliosis
We report the first occurrence of congenital scoliosis in an early Permian aquatic parareptile, Stereosternum tumidum from Parana ́ state, Brazil. The spine malformation is caused by a congenital hemivertebra. These observations give insight into the biomechanical aspects of underwater locomotion in an axial skeleton-compromised aquatic amniote. This is the oldest record of a hemivertebra in an aquatic animal
The oldest record of aquatic amniote congenital scoliosis
This research was supported by the National Science Center (Narodowe Centrum Nauki, www.ncn.gov.pl), Poland, project no. 2011/ 01/N/ST10/06989 granted to D. Surmik. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. There was no additional external funding received for this study.We report the first occurrence of congenital scoliosis in an early Permian aquatic parareptile, Stereosternum tumidum from Paraná state, Brazil. The spine malformation is caused by a congenital hemivertebra. These observations give insight into the biomechanical aspects of underwater locomotion in an axial skeleton-compromised aquatic amniote. This is the oldest record of a hemivertebra in an aquatic animal.National Science Center (Narodowe Centrum Nauki, www.ncn.gov.pl
Tuberculosis-like respiratory infection in 245-million-year-old marine reptile suggested by bone pathologies
An absence of ancient archaeological and palaeontological evidence of pneumonia contrasts with its recognition in the more recent archaeological record. We document an apparent infection-mediated periosteal reaction affecting the dorsal ribs in a Middle Triassic eosauropterygian historically referred to as ‘Proneusticosaurus’ silesiacus. High- resolution X-ray microtomography and histological studies of the pathologically altered ribs revealed the presence of a continuous solid periosteal reaction with multiple superficial blebs (protrusions) on the visceral surfaces of several ribs. Increased vascularization and uneven lines of arrested growth document that the pathology was the result of a multi- seasonal disease. While visceral surface localization of this periosteal reaction represents the earliest identified evidence for pneumonia, the blebs may have an additional implication: they have only been previously recognized in humans with tuberculosis (TB). Along with this diagnosis is the presence of focal vertebral erosions, parsimoniously compared to vertebral manifestation of TB in humans
Limb histology of the Triassic stem turtles Proterochersis porebensis Szczygielski & Sulej, 2016 and Proganochelys quenstedtii Baur, 1887 with insights into growth patterns of early turtles
Data on turtle limb bone histology and microstructure are spotty, especially for Mesozoic taxa, despite significant progress made in recent years. Here we provide first detailed information on the stylopodia of the Late Triassic stem turtles Proganochelys quenstedtii Baur, 1887 from Switzerland and Proterochersis porebensis Szczygielski & Sulej, 2016 from Poland. In both taxa we observed large, internal medullary regions filled with endosteal trabeculae and poorly to moderately vascularized parallel-fibered (grading locally to lamellar) periosteal cortices. Primary vasculature is predominantly longitudinal, in Proterochersis porebensis locally with radial inclination. In large specimens, secondary remodeling is significant in the deeper cortex, but it neither completely obliterates the primary tissue nor reaches the external surface of the bone in either taxon. Comparison of histological data, limb morphology, shell and limb lengths as well as proportions reveal differences in growth patterns between the taxa: Proganochelys quenstedtii seems to grow faster during early life stages than Proterochersis porebensis and attained distinctly larger body sizes earlier in ontogeny, even though the asymptotic body size is roughly the same for both species. Overall, the histological and microstructural characteristics of stylopodial bones of Triassic turtles more closely resemble those of more recent representatives of that group than earlier stem turtles
Kinetic Energy and Complementary Kinetic Energy in Gyrodynamics
Fundamental Concepts Following Crandall (1957) and Tabarrok (1981), we adopt the concepts of kinetic energy T, and complementary kinetic energy T*, as analogies to potential energy V and complementary potential energy V*. Using generalized coordinates q, and generalized momenta p, of analytical mechanics, the kinetic energy of a scleronomic (i.e., where the time t does not appear explicitly) system with n-degrees-of-freedom is defined by while its complementary kinetic energy is with / = 1, 2, 3, ..., n. For a point mass m on a straight path q, as an example, Generalized velocities and generalized momenta are obtained by partial differentiation and defined by q T{ p) dp/ Pi = ^-T*(q,q
New tomographic contribution to characterizing mesosaurid congenital scoliosis
The presence of a pathology in the vertebral column of the early Permian mesosaurid specimen
ZPAL R VII/1, being one of the oldest amniotic occurrences of congenital scoliosis
caused by a hemivertebra, was recently recognized. Here we provide CT data to further
characterize the phenomenon. The affected hemivertebra is wedged (incarcerated)
between the preceding and succeeding vertebrae. The neural canal is misshapen but continuous
and the number of dorsal ribs on each side of the specimen corresponds with the
number of the vertebrae, documenting its congenital (homeobox-related) derivation
Matrix Metalloproteinases in Cardioembolic Stroke : From Background to Complications
Matrix metalloproteinases (MMPs) are endopeptidases participating in physiological
processes of the brain, maintaining the blood–brain barrier integrity and playing a critical role in
cerebral ischemia. In the acute phase of stroke activity, the expression of MMPs increase and is
associated with adverse effects, but in the post-stroke phase, MMPs contribute to the process of
healing by remodeling tissue lesions. The imbalance between MMPs and their inhibitors results
in excessive fibrosis associated with the enhanced risk of atrial fibrillation (AF), which is the main
cause of cardioembolic strokes. MMPs activity disturbances were observed in the development of
hypertension, diabetes, heart failure and vascular disease enclosed in CHA2DS2VASc score, the scale
commonly used to evaluate the risk of thromboembolic complications risk in AF patients. MMPs
involved in hemorrhagic complications of stroke and activated by reperfusion therapy may also
worsen the stroke outcome. In the present review, we briefly summarize the role of MMPs in the
ischemic stroke with particular consideration of the cardioembolic stroke and its complications.
Moreover, we discuss the genetic background, regulation pathways, clinical risk factors and impact
of MMPs on the clinical outcome
Dinosaur senescence: a hadrosauroid with age-related diseases brings a new perspective of “old” dinosaurs
Senile vertebrates are extremely rare in the fossil record, making their recognition difficult. Here
we present the largest known representative of the Late Cretaceous hadrosauriform Gobihadros
mongoliensis showing features of cessation of growth indicating attainment of the terminal size.
Moreover, this is the first non-avian dinosaur with an age-related pathology recognized as primary
calcium pyrophosphate deposition disease indicating its advanced age. Because senile dinosaurs
are so rare and thus “senescence” in dinosaurs is unclear, we also propose a new unified definition of
a senile dinosaur: an individual which achieved the terminal size as revealed by the presence of the
external fundamental system and closed transcortical channels, has completely secondary remodeled
weight-bearing bones and possesses non-traumatic, non-contagious bone pathologies correlated with
advanced age
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