The opisthotonic posture of vertebrate skeletons: postmortem contraction or death throes?

Paleobiology ◽  
2007 ◽  
Vol 33 (2) ◽  
pp. 201-226 ◽  
Author(s):  
Cynthia Marshall Faux ◽  
Kevin Padian
Keyword(s):  
Causes Of Death ◽  
Viral Infections ◽  
Phylogenetic Signal ◽  
Spinal Curvature ◽  
Crown Group ◽  
Rigor Mortis ◽  
Dead Bird ◽  
Clinical Literature ◽  
The Central Nervous System ◽  
Strong Extension

An extreme, dorsally hyperextended posture of the spine (opisthotonus), characterized by the skull and neck recurved over the back, and with strong extension of the tail, is observed in many well-preserved, articulated amniote skeletons (birds and other dinosaurs, pterosaurs, and at least placental mammals). Postmortem water transport may explain some cases of spinal curvature in fossil tetrapods, but we show how these can be distinguished from causes of the opisthotonic posture, which is a biotic syndrome. Traditional biotic explanations nearly all involve postmortem causes, and have included rigor mortis, desiccation, and contraction of tendons and ligaments. However, examination of the process of rigor mortis and experimental observations of drying and salinity in carcasses of extant animals show that these explanations of the “dead bird” (opisthotonic) posture account for few or no cases. Differential contraction of cervical ligaments after death also does not produce the opisthotonic posture. It is not postmortem contraction but perimortem muscle spasms resulting from various afflictions of the central nervous system that cause these extreme postures. That is, the opisthotonic posture is the result of “death throes,” not postmortem processes, and individuals so afflicted assumed the posture before death, not afterward. The clinical literature has long recognized that such afflicted individuals perish from asphyxiation, lack of nourishment or essential nutrients, environmental toxins, or viral infections, among other causes. Accepting the actual causes of the opisthotonic posture as perimortem and not postmortem provides insights into the causes of death of fossilized specimens, and also revises interpretations of paleoenvironmental conditions of many fossil deposits. The opisthotonic posture tells us more about the circumstances surrounding death than about what happened after death. Finally, the opisthotonic posture appears to have a phylogenetic signal: it is so far reported entirely in ornithodiran archosaurs (dinosaurs and pterosaurs) and in crown-group placentals, though the distribution in mammals may expand with further study. It seems important that the opisthotonic posture has been observed extensively only in clades of animals that are known or thought to have high basal metabolic rates: hypoxia and related diseases would be most likely to affect animals with high oxygen use rates.

scholarly journals Neural Stem Cells: What Happens When They Go Viral?

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1468
Author(s):  
Yashika S. Kamte ◽  
Manisha N. Chandwani ◽  
Alexa C. Michaels ◽  
Lauren A. O’Donnell
Keyword(s):  
Stem Cells ◽  
Neural Stem Cells ◽  
Viral Infections ◽  
Wide Spectrum ◽  
Cell Types ◽  
Developmental Abnormalities ◽  
Multipotent Progenitor Cells ◽  
The Central Nervous System ◽  
Simplex Virus ◽  
The Brain

Viruses that infect the central nervous system (CNS) are associated with developmental abnormalities as well as neuropsychiatric and degenerative conditions. Many of these viruses such as Zika virus (ZIKV), cytomegalovirus (CMV), and herpes simplex virus (HSV) demonstrate tropism for neural stem cells (NSCs). NSCs are the multipotent progenitor cells of the brain that have the ability to form neurons, astrocytes, and oligodendrocytes. Viral infections often alter the function of NSCs, with profound impacts on the growth and repair of the brain. There are a wide spectrum of effects on NSCs, which differ by the type of virus, the model system, the cell types studied, and the age of the host. Thus, it is a challenge to predict and define the consequences of interactions between viruses and NSCs. The purpose of this review is to dissect the mechanisms by which viruses can affect survival, proliferation, and differentiation of NSCs. This review also sheds light on the contribution of key antiviral cytokines in the impairment of NSC activity during a viral infection, revealing a complex interplay between NSCs, viruses, and the immune system.

scholarly journals When the Blood Hits Your Brain: The Neurotoxicity of Extravasated Blood

2021 ◽  
Vol 22 (10) ◽  
pp. 5132
Author(s):  
Jesse A. Stokum ◽  
Gregory J. Cannarsa ◽  
Aaron P. Wessell ◽  
Phelan Shea ◽  
Nicole Wenger ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Surgical Intervention ◽  
Aneurysmal Subarachnoid Hemorrhage ◽  
Critical Factor ◽  
Mass Effect ◽  
Direct Role ◽  
Scientific Curiosity ◽  
Clot Removal ◽  
Clinical Literature ◽  
The Central Nervous System

Hemorrhage in the central nervous system (CNS), including intracerebral hemorrhage (ICH), intraventricular hemorrhage (IVH), and aneurysmal subarachnoid hemorrhage (aSAH), remains highly morbid. Trials of medical management for these conditions over recent decades have been largely unsuccessful in improving outcome and reducing mortality. Beyond its role in creating mass effect, the presence of extravasated blood in patients with CNS hemorrhage is generally overlooked. Since trials of surgical intervention to remove CNS hemorrhage have been generally unsuccessful, the potent neurotoxicity of blood is generally viewed as a basic scientific curiosity rather than a clinically meaningful factor. In this review, we evaluate the direct role of blood as a neurotoxin and its subsequent clinical relevance. We first describe the molecular mechanisms of blood neurotoxicity. We then evaluate the clinical literature that directly relates to the evacuation of CNS hemorrhage. We posit that the efficacy of clot removal is a critical factor in outcome following surgical intervention. Future interventions for CNS hemorrhage should be guided by the principle that blood is exquisitely toxic to the brain.

RIGOR MORTIS: PHYSIOLOGY

2021 ◽  
Vol 6 ◽  
Author(s):  
Heron Teixeira
Keyword(s):  
Body Weight ◽  
Causes Of Death ◽  
Natural Course ◽  
Important Task ◽  
Time Of Death ◽  
Post Mortem ◽  
Rigor Mortis ◽  
Intrinsic Factors ◽  
The Subject ◽  
Extrinsic And Intrinsic Factors

Introduction: Estimating the time of death is an important task in day-to-day forensic work and many factors for its designation are understood, one of which is rigor mortis. They can be altered by extrinsic and intrinsic factors, such as temperature location, humidity, heat, age, sex, length and body weight, and can be used as a parameter for approximate identification of the time of death. Objective: To carry out a brief review on the topic in order to promote a better understanding of the subject addressed and fully understand its physiology. Materials and Methods: Pubmed, Scielo and Medline databases were searched without date restrictions for articles published in English and Portuguese using the descriptors rigor mortis, autolysis and changes after death. Results: The theme presents consolidated researches regarding its natural course, being an important tool to estimate the time of death along other signs that appear after death, as well as to estimate some causes of death. Conclusion: Understanding the development of rigor mortis, helps to identify and distinguish processes that may have led to death and the post-mortem time.

Viral Encephalitis In Adults: A Narrative Review

2021 ◽  
Vol 16 ◽  
Author(s):  
Siciliano Valentina ◽  
Rosà Tommaso ◽  
Del Vecchio Pierluigi ◽  
D'Angelillo Anna ◽  
Brigida Mattia ◽  
...  
Keyword(s):  
Viral Encephalitis ◽  
Viral Infections ◽  
Direct Action ◽  
Ventilatory Support ◽  
Signs And Symptoms ◽  
Altered Mental Status ◽  
Poor Quality ◽  
Electrolyte Disorders ◽  
The Central Nervous System

: Viral infections of the central nervous system cause frequent hospitalization. The pathogenesis of viral encephalitis involves both the direct action of invading pathogens and the damage generated by the inflammatory reaction they trigger. The type of signs and symptoms presented by the patient depends on the severity and location of the ongoing inflammatory process. Most of the viral encephalitides are characterized by an acute development, fever, variable alterations in consciousness (confusion, lethargy, even coma), seizures (focal and generalized) and focal neurologic signs. The specific diagnosis of encephalitis is usually based on lumbar puncture. Cerebrospinal fluid examination should be performed in all patients unless absolutely contraindicated. Also, electroencephalogram and neuroimaging play a prominent role in diagnosis. Airway protection, ventilatory support, the management of raised intracranial pressure and correction of electrolyte disorders must be immediately considered in a patient with altered mental status. The only therapy strictly recommended is acyclovir in HSV encephalitis. The use of adjunctive glucocorticoids has poor-quality evidence in HSV, EBV, or VZV encephalitis. The role of antiviral therapy in other types of viral encephalitis is not well defined.

Infections of the Central Nervous System

2013 ◽  
pp. 114-127
Author(s):  
Françoise Gray ◽  
Kum Thong Wong ◽  
Francesco Scaravilli ◽  
Leroy R. Sharer
Keyword(s):  
Human Immunodeficiency Virus ◽  
Viral Infections ◽  
Opportunistic Infections ◽  
Parasitic Infections ◽  
System P ◽  
Immune Mediated ◽  
Wide Range ◽  
Immunodeficiency Virus ◽  
The Central Nervous System ◽  
Specific Agent

This chapter describes and illustrates the different lesions observed in CNS infections. A wide variety of pathogenic infectious organisms may affect the CNS. They can be classified as “pathogenic” (causing disease in every individual) or “opportunistic” (affecting only patients with immunodeficiency). Bacteria may cause pyogenic infections or so-called “specific infections,” in which the morphology of the lesions is suggestive of a specific agent. Mycoses and parasitic infections used to be uncommon, restricted to certain countries; however, due to increasing incidence of immunodeficiency conditions and intercontinental travel, they are now more frequently encountered. Viral infections of the CNS cause nonspecific lesions due to immune-mediated reactions or more specific encephalitides. In AIDS, infection by the human immunodeficiency virus causes a unique encephalitis and immunodeficiency with a wide range of secondary opportunistic infections.

scholarly journals Intranasal Borna Disease Virus (BoDV-1) Infection: Insights into Initial Steps and Potential Contagiosity

2019 ◽  
Vol 20 (6) ◽  
pp. 1318 ◽  
Author(s):  
Alexandra Kupke ◽  
Sabrina Becker ◽  
Konstantin Wewetzer ◽  
Barbara Ahlemeyer ◽  
Markus Eickmann ◽  
...  
Keyword(s):  
Viral Infections ◽  
Cell Types ◽  
Nerve Fibers ◽  
Olfactory Pathway ◽  
Adult Rats ◽  
The Central Nervous System ◽  
Receptor Neurons

Mammalian Bornavirus (BoDV-1) typically causes a fatal neurologic disorder in horses and sheep, and was recently shown to cause fatal encephalitis in humans with and without transplant reception. It has been suggested that BoDV-1 enters the central nervous system (CNS) via the olfactory pathway. However, (I) susceptible cell types that replicate the virus for successful spread, and (II) the role of olfactory ensheathing cells (OECs), remained unclear. To address this, we studied the intranasal infection of adult rats with BoDV-1 in vivo and in vitro, using olfactory mucosal (OM) cell cultures and the cultures of purified OECs. Strikingly, in vitro and in vivo, viral antigen and mRNA were present from four days post infection (dpi) onwards in the olfactory receptor neurons (ORNs), but also in all other cell types of the OM, and constantly in the OECs. In contrast, in vivo, BoDV-1 genomic RNA was only detectable in adult and juvenile ORNs, nerve fibers, and in OECs from 7 dpi on. In vitro, the rate of infection of OECs was significantly higher than that of the OM cells, pointing to a crucial role of OECs for infection via the olfactory pathway. Thus, this study provides important insights into the transmission of neurotropic viral infections with a zoonotic potential.

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