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Uwe Kierdorf – One of the best experts on this subject based on the ideXlab platform.

  • multiple osteochondromas of the Antlers and cranium in a free ranging white tailed deer odocoileus virginianus
    PLOS ONE, 2017
    Co-Authors: Uwe Kierdorf, Santiago Gomez, Karl V Miller, Stefan Flohr, Horst Kierdorf

    Abstract:

    This paper reports a case of multiple osteochondromas affecting the Antlers and the left zygomatic bone of a free-ranging adult white-tailed buck (Odocoileus virginianus) from Georgia, USA. Along with a few postcranial bones, the antlered cranium of the individual was found in a severely weathered condition and devoid of any soft tissue. The Antlers exhibited five pedunculated exostoses that were composed of cancellous bone and, in their peripheral portions, also mineralized cartilage. The largest of the exostoses, located on the right antler, had a maximum circumference of 55 cm. The exostosis arising from the zygomatic bone was broad-based and much smaller than the exophytic outgrowths on the Antlers. Diagnosis of the exostoses as osteochondromas was based on their overall morphology, the normal bone structure in their stalk regions, and the continuity of their spongiosa and cortex with the respective components of the parent bones. Antleromas, i.e., pathological outgrowths developing on Antlers as a result of insufficient androgen production, were excluded in the differential diagnosis, based on (1) the apparent maturity and, except for the tumors, normal shape of the Antlers and (2) the fact that exostosis formation had also affected the zygomatic bone. Previously only a single case of solitary osteochondroma of an antler has been described in the scientific literature. The case presented here is the first report of multiple osteochondromas in a deer. As Antlers are regularly collected as trophies, and huge numbers of them are critically inspected each year, the fact that thus far only two cases of antler osteochondromas have been reported suggests that these tumors are very rare.

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  • labeling studies on cortical bone formation in the Antlers of red deer cervus elaphus
    Bone, 2013
    Co-Authors: Santiago Gomez, Laureano Gallego, Andrés J. Garcia, Uwe Kierdorf, Horst Kierdorf, Tomas Landetecastillejos, Salvador Luna

    Abstract:

    The formation and mineralization process of Antlers, which constitute the fastest growing bones in vertebrates, is still not fully understood. We used oxytetracycline injections to label different stages of bone formation in Antlers of 14 red deer between days 28 and 156 of antler growth. Results show that initially a trabecular scaffold of woven bone is formed which largely replaces a pre-existing scaffold of mineralized cartilage. Lamellar bone is then deposited and from about day 70 onwards, primary osteons fill in the longitudinal tubes lined by the scaffold in a proximal to distal sequence. Mineral apposition rate (MAR) in early stages of primary osteon formation is very high (average 2.15 μm/d). Lower MARs were recorded for later stages of primary osteon formation (1.56 μm/d) and for the smaller secondary osteons (0.89 μm/d). Results suggest a peak in mineral demand around day 100 when the extent of mineralizing surfaces is maximal. A few secondary osteons were formed in a process of antler modeling rather than remodeling, as it occurred simultaneously with formation of primary osteons. The degree of cortical porosity reflects a reduction in MAR during later stages of osteonal growth, whereas cortical thickness is determined earlier. Injections given when the Antlers were largely or completely clean from velvet produced no labels in antler bone, strongly suggesting that Antlers are dead after velvet shedding. The rapidity of antler mineralization and the short lifespan of Antlers make them an extraordinary model to assess the effects of chemicals impairing or promoting bone mineralization.

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  • deer Antlers a model of mammalian appendage regeneration an extensive review
    Gerontology, 2011
    Co-Authors: Uwe Kierdorf, Horst Kierdorf

    Abstract:

    Background: Compared with other vertebrate taxa, mammals possess a very limited capacity for appendage regeneration. The Antlers of deer are an exception in that they are periodically lost and fully regenerated throughout the life of an individual. Objective: In this paper we compare certain aspects of antler regeneration with regenerative processes in other vertebrates. Methods: Review of the literature. Results: Recent studies suggest that antler regeneration is a stem cell-based process and that these stem cells are located in the pedicle periosteum. There is evidence that signaling pathways known to operate during appendage regeneration in other vertebrates are also activated during antler regeneration. There are, however, also differences between Antlers and other systems of epimorphic regeneration. Thus, contrary to amphibian limb regeneration, signaling from the wound epidermis appears not to be of crucial importance for antler regeneration. Healing of the casting wound typically involves no or only minor scarring, making Antlers interesting subjects for researchers attempting to reduce scar formation during wound healing in humans. The fact that despite their enormous growth rate the Antlers of intact and castrated deer appear to be resistant to malignant transformation furthermore offers research opportunities for cancer biology. Conclusions: Studying antler renewal as an example of mammalian appendage regeneration may provide crucial information for regenerative medicine to achieve its ultimate goal of stimulating limb regeneration in humans. A deeper understanding of the developmental mechanisms involved in antler renewal can also be useful for controlling induced regeneration processes in mammals.

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Laureano Gallego – One of the best experts on this subject based on the ideXlab platform.

  • Effects of public vs. private management on deer antler composition, mechanical and structural variables
    European Journal of Wildlife Research, 2013
    Co-Authors: Tomás Landete-castillejos, José A. Estevez, Francisco Ceacero, Andrés J. Garcia, Laureano Gallego

    Abstract:

    Previous studies have shown that antler mineral composition reflects diet. Thus, management involving diet can influence both the mineral composition and mechanical properties of Antlers. However, it is not known if reducing population density, which increases availability of food, can compensate mineral deficiencies arising from lack of minerals in plants and, ultimately, in the soil. The present study aimed at assessing if private management often involving a balanced food supplementation produced differences in antler properties compared to both public management and reference Antlers from deer farms. We also examined if low population density in a National Park could compensate for mineral deficiencies found in Antlers of other public reserves or else, Antlers still differed in antler characteristics compared to supplemented deer in private game estates. We used 120 Antlers from three public reserves, four private game estates and two deer farms as reference to assess antler composition, mechanical properties, size and structure. Public managed Antlers had shorter length compared to private and reference ones, thinner cortex (CT), were less dense, had lower second moment of area ( I ) and work to fracture ( W ). In addition, they had content in ash, Ca, Mg, Na, S and Zn lower than Antlers from private game estates. In contrast, Antlers from public reserves had greater values of Young’s modulus of elasticity ( E ), Fe, Mn and Si. In most cases, Antlers from private management and reference farms showed similar values. When comparing Antlers from low population density in a National Park with Antlers from private management, differences in antler length, CT, I and ash disappeared, but both differed still in density, E , bending strength, W and content in all minerals mentioned. In conclusion, low density can improve some structural variables, but it cannot compensate for mineral deficiencies whereas food supplementation can.

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  • labeling studies on cortical bone formation in the Antlers of red deer cervus elaphus
    Bone, 2013
    Co-Authors: Santiago Gomez, Laureano Gallego, Andrés J. Garcia, Uwe Kierdorf, Horst Kierdorf, Tomas Landetecastillejos, Salvador Luna

    Abstract:

    The formation and mineralization process of Antlers, which constitute the fastest growing bones in vertebrates, is still not fully understood. We used oxytetracycline injections to label different stages of bone formation in Antlers of 14 red deer between days 28 and 156 of antler growth. Results show that initially a trabecular scaffold of woven bone is formed which largely replaces a pre-existing scaffold of mineralized cartilage. Lamellar bone is then deposited and from about day 70 onwards, primary osteons fill in the longitudinal tubes lined by the scaffold in a proximal to distal sequence. Mineral apposition rate (MAR) in early stages of primary osteon formation is very high (average 2.15 μm/d). Lower MARs were recorded for later stages of primary osteon formation (1.56 μm/d) and for the smaller secondary osteons (0.89 μm/d). Results suggest a peak in mineral demand around day 100 when the extent of mineralizing surfaces is maximal. A few secondary osteons were formed in a process of antler modeling rather than remodeling, as it occurred simultaneously with formation of primary osteons. The degree of cortical porosity reflects a reduction in MAR during later stages of osteonal growth, whereas cortical thickness is determined earlier. Injections given when the Antlers were largely or completely clean from velvet produced no labels in antler bone, strongly suggesting that Antlers are dead after velvet shedding. The rapidity of antler mineralization and the short lifespan of Antlers make them an extraordinary model to assess the effects of chemicals impairing or promoting bone mineralization.

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  • Factors affecting antler investment in Iberian red deer
    Animal Production Science, 2012
    Co-Authors: José Gómez, Tomás Landete-castillejos, Francisco Ceacero, Andrés J. Garcia, E. Gaspar-lópez, Laureano Gallego

    Abstract:

    Antler constitutes such a costly trait that the skeleton of the deer undergoes a process similar to osteoporosis to meet the high demands of mineral deposition in the antler. The allometric relationship between antler and body size is one of the oldest known. However, no study has assessed the proportion that Antlers constitute with regard to the skeleton (from which most of the material is drawn), nor which factors influence this investment. To assess this, we studied 171 males (aged 1-5 years), determined their antler and bodyweights and scored their body condition. Then we calculated antler investment as antler weight relative to estimated skeletal weight. Results showed that antler investment in males 2 years old (i.e. excluding yearlings) depended on age rather than the whole bodyweight or body condition. Antler investment increased from 6% in yearlings to 35% in 5-year-old males, with a mean of 19%. A GLMM showed that in males 2 years old, within age, the heavier the male and the better the body condition at the start of antler growth, the greater the investment in Antlers. In yearlings, antler investment did not depend on bodyweight or body condition. In conclusion, antler weight relative to skeleton weight is a good method to assess antler investment. This investment is influenced by age and, in males 2 years old, also by bodyweight or condition at the start of antler growth.

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Horst Kierdorf – One of the best experts on this subject based on the ideXlab platform.

  • multiple osteochondromas of the Antlers and cranium in a free ranging white tailed deer odocoileus virginianus
    PLOS ONE, 2017
    Co-Authors: Uwe Kierdorf, Santiago Gomez, Karl V Miller, Stefan Flohr, Horst Kierdorf

    Abstract:

    This paper reports a case of multiple osteochondromas affecting the Antlers and the left zygomatic bone of a free-ranging adult white-tailed buck (Odocoileus virginianus) from Georgia, USA. Along with a few postcranial bones, the antlered cranium of the individual was found in a severely weathered condition and devoid of any soft tissue. The Antlers exhibited five pedunculated exostoses that were composed of cancellous bone and, in their peripheral portions, also mineralized cartilage. The largest of the exostoses, located on the right antler, had a maximum circumference of 55 cm. The exostosis arising from the zygomatic bone was broad-based and much smaller than the exophytic outgrowths on the Antlers. Diagnosis of the exostoses as osteochondromas was based on their overall morphology, the normal bone structure in their stalk regions, and the continuity of their spongiosa and cortex with the respective components of the parent bones. Antleromas, i.e., pathological outgrowths developing on Antlers as a result of insufficient androgen production, were excluded in the differential diagnosis, based on (1) the apparent maturity and, except for the tumors, normal shape of the Antlers and (2) the fact that exostosis formation had also affected the zygomatic bone. Previously only a single case of solitary osteochondroma of an antler has been described in the scientific literature. The case presented here is the first report of multiple osteochondromas in a deer. As Antlers are regularly collected as trophies, and huge numbers of them are critically inspected each year, the fact that thus far only two cases of antler osteochondromas have been reported suggests that these tumors are very rare.

    Free Register to Access Article

  • labeling studies on cortical bone formation in the Antlers of red deer cervus elaphus
    Bone, 2013
    Co-Authors: Santiago Gomez, Laureano Gallego, Andrés J. Garcia, Uwe Kierdorf, Horst Kierdorf, Tomas Landetecastillejos, Salvador Luna

    Abstract:

    The formation and mineralization process of Antlers, which constitute the fastest growing bones in vertebrates, is still not fully understood. We used oxytetracycline injections to label different stages of bone formation in Antlers of 14 red deer between days 28 and 156 of antler growth. Results show that initially a trabecular scaffold of woven bone is formed which largely replaces a pre-existing scaffold of mineralized cartilage. Lamellar bone is then deposited and from about day 70 onwards, primary osteons fill in the longitudinal tubes lined by the scaffold in a proximal to distal sequence. Mineral apposition rate (MAR) in early stages of primary osteon formation is very high (average 2.15 μm/d). Lower MARs were recorded for later stages of primary osteon formation (1.56 μm/d) and for the smaller secondary osteons (0.89 μm/d). Results suggest a peak in mineral demand around day 100 when the extent of mineralizing surfaces is maximal. A few secondary osteons were formed in a process of antler modeling rather than remodeling, as it occurred simultaneously with formation of primary osteons. The degree of cortical porosity reflects a reduction in MAR during later stages of osteonal growth, whereas cortical thickness is determined earlier. Injections given when the Antlers were largely or completely clean from velvet produced no labels in antler bone, strongly suggesting that Antlers are dead after velvet shedding. The rapidity of antler mineralization and the short lifespan of Antlers make them an extraordinary model to assess the effects of chemicals impairing or promoting bone mineralization.

    Free Register to Access Article

  • deer Antlers a model of mammalian appendage regeneration an extensive review
    Gerontology, 2011
    Co-Authors: Uwe Kierdorf, Horst Kierdorf

    Abstract:

    Background: Compared with other vertebrate taxa, mammals possess a very limited capacity for appendage regeneration. The Antlers of deer are an exception in that they are periodically lost and fully regenerated throughout the life of an individual. Objective: In this paper we compare certain aspects of antler regeneration with regenerative processes in other vertebrates. Methods: Review of the literature. Results: Recent studies suggest that antler regeneration is a stem cell-based process and that these stem cells are located in the pedicle periosteum. There is evidence that signaling pathways known to operate during appendage regeneration in other vertebrates are also activated during antler regeneration. There are, however, also differences between Antlers and other systems of epimorphic regeneration. Thus, contrary to amphibian limb regeneration, signaling from the wound epidermis appears not to be of crucial importance for antler regeneration. Healing of the casting wound typically involves no or only minor scarring, making Antlers interesting subjects for researchers attempting to reduce scar formation during wound healing in humans. The fact that despite their enormous growth rate the Antlers of intact and castrated deer appear to be resistant to malignant transformation furthermore offers research opportunities for cancer biology. Conclusions: Studying antler renewal as an example of mammalian appendage regeneration may provide crucial information for regenerative medicine to achieve its ultimate goal of stimulating limb regeneration in humans. A deeper understanding of the developmental mechanisms involved in antler renewal can also be useful for controlling induced regeneration processes in mammals.

    Free Register to Access Article