Cartilage Calcification

The progression of mineral phase deposition in hypertrophic cartilage and periosteal bone matrix was studied in human metacarpals primary ossification centers before vascular invasion began. This study aimed to provide a morphologic/morphometric comparative analysis of the calcification process in cartilage and periosteal osteoid used as models of endochondral ossification. Thin, sequential sections from the same paraffin inclusions of metacarpal anlagen (gestational age between the 20th and 22nd weeks) were examined with light microscopy and scanning electron microscopy, either stained or heat-deproteinated. This process enabled the analysis of corresponding fields using the different methods. From the initial CaPO nucleation in cartilage matrix, calcification progressed increasing the size of focal, globular, randomly distributed deposits (size range 0.5-5 µm), followed by aggregation into polycyclic clusters and finally forming a dense, compact mass of calcified cartilage. At the same time, the early osteoid calcification was characterized by a fine granular pattern (size range 0.1-0.5 µm), which was soon compacted in the layer of the first periosteal lamella. Scanning electron microscopy of heat-deproteinated sections revealed a rod-like hydroxyapatite crystallite pattern, with only size differences between the early globular deposits of the two calcifying matrices. The morphology of the early calcium deposits was similar in both cartilage and osteoid, with variations in size and density only. However, integration of the reported data with the actual hypotheses of the mechanisms of Ca concentration suggested that ion transport was linked to the progression of the chondrocyte maturation cycle (with recall of H O from the matrix) in cartilage, while ions transport was an active process through the cell membrane in osteoid. Other considered factors were the collagen type specificity and the matrix fibrillar texture. Anat Rec, 301:571-580, 2018. © 2017 Wiley Periodicals, Inc.

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Study of Endochondral Ossification in Human Fetalcartilage Anlagen of Metacarpals: Comparative Morphology of Mineral Deposition in Cartilage and in the Periosteal Bone Matrix

Pazzaglia

Reguzzoni

Pagani

et al. 2018

“…The particular texture that denotes the stylohyal of Dinilysia and basal snakes such as “anilioids” and Xenopeltis may indicate an important degree of endochondral calcification that characterizes the stylohyal as a cartilaginous tissue (see Maisano, ), a process that occurs through deposition of granular organic‐inorganic particles in the cartilage matrix (Bonucci and Gómez, ). Although a histological study is necessary to confirm the nature of the stylohyal in Dinilysia and snakes, the homology of this structure with the intercalary cartilage of nonophidian lizards can be invoked as another line of evidence that supports this inference.…”

Section: Discussionmentioning

confidence: 99%

Postnatal Development of the Skull of Dinilysia patagonica (Squamata‐Stem Serpentes)

Scanferla

Bhullar

2014

The snake skull represents a profound transformation of the ancestral squamate cranium in which dermal skull roof bones were integrated with the braincase, in a manner convergent with that which occurred during the origin of mammals. However, the ontogeny of snake characters at the origin of the clade has until now been inaccessible. Here we describe a postnatal ontogenetic series of the Late Cretaceous stem snake Dinilysia patagonica and compare it to that of extant lizards and snakes. Comparative analysis indicates notable ontogenetic changes, including advanced state of ossification, isometric growth of the otic capsule, fusion of the stylohyal to the quadrate, and great posterior elongation of the supratemporal. Of these transformations, the unfused condition of braincase bones and the retention of a large otic capsule in adults are examples of paedomorphic and peramorphic processes, respectively. Some ontogenetic transformations detected, in particular those present in middle ear, skull roof and suspensorium, are strikingly similar to those present in extant snakes. Nevertheless, Dinilysia retains a lizard-like paroccipital process without an epiphyseal extremity, and a calcified epiphysis that caps the sphenoccipital tubercle. Finally, the integration of the dermal skull roof with the braincase is similar to that seen in mammals with regard to the overall closure of the braincase, but the two evolutionary and developmental modules appear less integrated in snakes in that the parietal bone of the dermal skull roof progressively overlaps the supraoccipital of the chondrocranial braincase.

“…It has been demonstrated that the collagen molecules act as templates for mineral deposition (Landis et al, 1996;Landis and Silver, 2002;Doherty, 2010;Bonucci and Gomez, 2012). Thus, mineralization can be inferred by the increase of the areas stained in pink in the cartilage ECM, which indicate an increase in the collagen secretion.…”

Section: Histological and Histochemical Analysesmentioning

confidence: 99%

Further Data on Sesamoid Identity from Two Anuran Species

Vera

Ponssa

Abdala

2015

Considering that the identification of equivalent entities is the basis for any comparative analysis, we compare the histology, histochemistry, shape and dimensions of epiphyses, carpal and sesamoids in two anuran frogs. Our goal was to explore the morphological correspondence among these three skeletal elements in order to clarify the sesamoid identity. We studied the skeletogenesis, contour geometric morphometry and dimensions of forelimb elements of juveniles of two anurans species Leptodactylus bufonius and Rhinella arenarum. Skeletogenesis in anurans present a common trait between carpals and sesamoids: both elements exhibit endochondral ossification. A difference between these elements is the presence of fibrocartilage in the development of sesamoids. The geometric morphometry does not allow us to establish a shape pattern that can be compared either between sesamoids and epiphyses or carpals. With regard to dimensions, our data indicate that bones categorization based on these aspects is ambiguous and therefore is useless to classify of skeletal bones. The data about tissue differentiation of sesamoids provide evidence that support the idea that these elements should be considered part of the typical endowment of the vertebrate skeleton. Anat Rec, 298:1376Rec, 298: -1394Rec, 298: , 2015. V C 2015 Wiley Periodicals, Inc.