scholarly journals The developmental relationship between teeth and dermal odontodes in the most primitive bony fish Lophosteus

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Donglei Chen ◽  
Henning Blom ◽  
Sophie Sanchez ◽  
Paul Tafforeau ◽  
Tiiu Märss ◽  
...  
Keyword(s):  
Bony Fish ◽  
Ossification Center ◽  
Single System ◽  
Adult Morphology ◽  
Developmental Relationship ◽  
Bony Plate ◽  
Ontogenetic Trajectory ◽  
Sequential Addition ◽  
Synchrotron Microtomography

The ontogenetic trajectory of a marginal jawbone of Lophosteus superbus (Late Silurian, 422 Million years old), the phylogenetically most basal stem osteichthyan, visualized by synchrotron microtomography, reveals a developmental relationship between teeth and dermal odontodes that is not evident from the adult morphology. The earliest odontodes are two longitudinal founder ridges formed at the ossification center. Subsequent odontodes that are added lingually to the ridges turn into conical teeth and undergo cyclic replacement, while those added labially achieve a stellate appearance. Stellate odontodes deposited directly on the bony plate are aligned with the alternate files of teeth, whereas new tooth positions are inserted into the files of sequential addition when a gap appears. Successive teeth and overgrowing odontodes show hybrid morphologies around the oral-dermal boundary, suggesting signal cross-communication. We propose that teeth and dermal odontodes are modifications of a single system, regulated and differentiated by the oral and dermal epithelia.

scholarly journals Dental ontogeny in the most primitive bony fish Lophosteus reveals the developmental relationship between teeth and dermal odontodes

2020 ◽  
Author(s):  
Donglei Chen ◽  
Henning Blom ◽  
Sophie Sanchez ◽  
Paul Tafforeau ◽  
Tiiu Märss ◽  
...  
Keyword(s):  
Bony Fish ◽  
Ossification Center ◽  
Developmental Relationships ◽  
Adult Morphology ◽  
Developmental Relationship ◽  
Bony Plate ◽  
Dental Ontogeny ◽  
Synchrotron Microtomography

AbstractOntogenetic data obtained by synchrotron microtomography of a marginal jawbone of Lophosteus superbus (Late Silurian, 422 Million years old), the phylogenetically basalmost stem osteichthyan, reveal developmental relationships between teeth and ornament that are not obvious from the adult morphology. The earliest odontodes are two longitudinal founder ridges formed at the ossification center. Subsequent odontodes that are added lingually to the ridges turn into conical teeth and undergo cyclic replacement, while those added labially achieve a stellate appearance. The stellate odontodes deposited directly on the bony plate are aligned with the alternate files of the teeth. Successive odontodes overgrowing the labial tooth rows become tooth-like and the replacement teeth near to them are ornament-like. We propose that teeth and ornament are modifications of a single odontode system regulated and differentiated by the oral and dermal signals; signal cross-communication between the two domains can occur around the oral-dermal boundary.

scholarly journals Author response: The developmental relationship between teeth and dermal odontodes in the most primitive bony fish Lophosteus

2020 ◽  
Author(s):  
Donglei Chen ◽  
Henning Blom ◽  
Sophie Sanchez ◽  
Paul Tafforeau ◽  
Tiiu Märss ◽  
...  
Keyword(s):  
Bony Fish ◽  
Author Response ◽  
Developmental Relationship

Langerhans-Zell-Histiozytose (LCH)

2014 ◽  
Vol 14 (04) ◽  
pp. 253-259
Author(s):  
C. Hutter ◽  
L. Ronceray ◽  
K. Lakatos ◽  
M. Minkov ◽  
W. Holter ◽  
...  
Keyword(s):  
Single System

ZusammenfassungDie Langerhans-Zell-Histiozytose (LCH) ist eine seltene histiozytäre Erkrankung (Inzidenz: 0,2–2,0/100 000 Kinder unter 15 Jahren) mit einem sehr heterogenen klinischen Verlauf. Spontane Regressionen werden ebenso beobachtet wie chronische Reaktivierungen. Das klinische Spektrum reicht von einem isolierten Befall des Skeletts oder der Haut, bis hin zur ausgedehnten Multiorganerkrankung mit einem progredienten und lebensbedrohli-chen Verlauf. Das diagnostische und therapeutische Vorgehen konnte durch prospektive internationale Studien der Histiocyte Society standardisiert werden. Dies resultiert in einer Verbesserung von Heilungsrate und Prognose. Je nach Krankheitsausdehnung reicht die Behandlungsstrategie von einer abwartenden Haltung oder dem Einsatz einer lokalen/topischen Therapie bei monosystemischer LCH (single system LCH; SS-LCH) bis hin zur systemischen Chemotherapie bei multi-systemischer LCH (MS-LCH). Auch auf dem Gebiet der Grundlagenforschung konnten in den letzten Jahren große Fortschritte im Hinblick auf ein besseres Verständnis der Biologie und Pathogenese der Erkrankung erzielt werden. Die dabei gewonnenen Informationen werden als Grundlage für neue Therapieansätze dienen.

The Inhibition of Platelet Aggregation by an Aorta Intima Extract

1974 ◽  
Vol 32 (02/03) ◽  
pp. 417-431 ◽  
Author(s):  
A. du P Heyns ◽  
D. J van den Berg ◽  
G. M Potgieter ◽  
F. P Retief
Keyword(s):  
Platelet Aggregation ◽  
Degradation Products ◽  
Adenosine Diphosphate ◽  
Inhibitory Effect ◽  
Protective Role ◽  
Vascular Trauma ◽  
Wear And Tear ◽  
Sequential Addition ◽  
Aggregation Activity

SummaryThe platelet aggregating activity of extracts of different layers of the arterial wall was compared to that of Achilles tendon. Arterial media and tendon extracts, adjusted to equivalent protein content as an index of concentration, aggregated platelets to the same extent but an arterial intima extract did not aggregate platelets. Platelet aggregation induced by collagen could be inhibited by mixing with intima extract, but only to a maximum of about 80%. Pre-mixing adenosine diphosphate (ADP) with intima extracts diminished the platelet aggregation activity of the ADP. Depending on the relationship between ADP and intima extract concentrations aggregating activity could either be completely inhibited or inhibition abolished. Incubation of ADP with intima extract and subsequent separation of degradation products by paper chromatography, demonstrated a time-dependent breakdown of ADP with AMP, adenosine, inosine and hypoxanthine as metabolic products; ADP removal was complete. Collagen, thrombin and adrenaline aggregate platelets mainly by endogenous ADP of the release reaction. Results of experiments comparing inhibition of aggregation caused by premixing aggregating agent with intima extract, before exposure to platelets, and the sequential addition of first the intima extract and then aggregating agent to platelets, suggest that the inhibitory effect of intima extract results from ADP breakdown. It is suggested that this ADP degradation by intima extract may play a protective role in vivo by limiting the size of platelet aggregates forming at the site of minimal “wear and tear” vascular trauma.

The potential of continuous library and information education within the context of the Model Standard of Public Library

2017 ◽  
pp. 83-93 ◽  
Author(s):  
Galina Kuzichkina ◽  
Alexander Mazuritsky
Keyword(s):  
Professional Education ◽  
Reference Point ◽  
Public Libraries ◽  
Public Library ◽  
Single System ◽  
Library And Information Education

The authors discuss the problems of library and information education. The lack of a single system of life-long education in the library industry is stressed. The Model Standard of Public Libraries as a reference point for education reinvention is analyzed. The main vectors of public libraries activities defined in the Model Standard are considered, along with the desirable professional competences. The ratio of the libraries’ main tasks and functionalities and the professional education is examined.

THE CLASSIC GENRE OF THE ORAL TRADITION OF AZERBAIJAN IS "MUGHAM"

2020 ◽  
pp. 6-10
Author(s):  
Mammadov R.
Keyword(s):  
Folk Music ◽  
Oral Tradition ◽  
Single System ◽  
Musical Culture ◽  
Musical Tradition

This article is dedicated to the classical mugham genre. It analyzes the main genres of musical culture in Azerbaijan. The author studies the process of emergence of this genre, as well as its main types. Studies folk and national musical art, analyzes the classification of all genres of the oral musical tradition and combines them into a single system of genres of Azerbaijani folk music.

Apophysites – Revue de la littérature et ­nouvelles directions

2014 ◽  
Vol 62 (3) ◽  
Keyword(s):  
Scientific Evidence ◽  
Ossification Center ◽  
Health Staff ◽  
Optimal Management ◽  
Long Term Effect ◽  
High Incidence ◽  
Youth Athlete ◽  
Pathology Education ◽  
Main Factor

Apophysitis are part of the growth-related diseases within youth athlete population. Despite their high incidence within this growing cohort, many doubts remain. The physiopathology is still debated. Initially, the fragmentation of the ossification center was seen as the main factor of the disease. For few years, this theory has been questioned due to consistent signs of tendon suffering. Apophysitis may have some negative long-term effect on a sporting career. There is currently poor scientific evidence on the optimal management and no treatment has been widely accepted. Prevention remains the most powerful intervention in this particular pathology. Education of the athlete’s sporting entourage (family, coaches and health staff) and the athlete himself is necessary to act quickly and adapt the training load to decrease mechanical stress on the suffering apophysis.

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