The Experts below are selected from a list of 276 Experts worldwide ranked by ideXlab platform
Niels Lynnerup - One of the best experts on this subject based on the ideXlab platform.
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Petrous Bone diagenesis: a multi-analytical approach
Palaeogeography Palaeoclimatology Palaeoecology, 2019Co-Authors: Ioannis Kontopoulos, Kirsty Penkman, Graeme D. Mcallister, Niels Lynnerup, Peter De Barros Damgaard, Henrik B. Hansen, Morten E. Allentoft, Matthew J. CollinsAbstract:Abstract The discovery of Petrous Bone as an excellent repository for ancient biomolecules has been a turning point in biomolecular archaeology, especially in aDNA research, but excessive and uncontrolled sampling could result in loss of this valuable resource for future research. This study reports on the histological (optical microscopy), physical (FTIR-ATR), elemental (CHN) and biochemical (collagen and DNA analysis) preservation of 15 human Petrous Bones spanning from the c. 2100 BCE to 1850 CE. Through the combined application of a number of diagenetic parameters (general histological index; infrared splitting factor; carbonate/phosphate ratio; amide/phosphate ratio; col wt%; % C, % N and C/N of whole Bone and collagen; % endogenous DNA), we provide new insights into Petrous Bone micromorphological characteristics and diagenesis, and new evidence to enhance screening practices for aDNA and collagen analysis.
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comparing ancient dna preservation in Petrous Bone and tooth cementum
PLOS ONE, 2017Co-Authors: Henrik B. Hansen, Niels Lynnerup, Peter De Barros Damgaard, Ashot Margaryan, Jesper Stenderup, Eske Willerslev, Morten E. AllentoftAbstract:Large-scale genomic analyses of ancient human populations have become feasible partly due to refined sampling methods. The inner part of Petrous Bones and the cementum layer in teeth roots are currently recognized as the best substrates for such research. We present a comparative analysis of DNA preservation in these two substrates obtained from the same human skulls, across a range of different ages and preservation environments. Both substrates display significantly higher endogenous DNA content (average of 16.4% and 40.0% for teeth and Petrous Bones, respectively) than parietal skull Bone (average of 2.2%). Despite sample-to-sample variation, Petrous Bone overall performs better than tooth cementum (p = 0.001). This difference, however, is driven largely by a cluster of viking skeletons from one particular locality, showing relatively poor molecular tooth preservation (<10% endogenous DNA). In the remaining skeletons there is no systematic difference between the two substrates. A crude preservation (good/bad) applied to each sample prior to DNA-extraction predicted the above/below 10% endogenous DNA threshold in 80% of the cases. Interestingly, we observe signficantly higher levels of cytosine to thymine deamination damage and lower proportions of mitochondrial/nuclear DNA in Petrous Bone compared to tooth cementum. Lastly, we show that Petrous Bones from ancient cremated individuals contain no measurable levels of authentic human DNA. Based on these findings we discuss the pros and cons of sampling the different elements.
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the Petrous Bone a new sampling site for identifying early dietary patterns in stable isotopic studies
American Journal of Physical Anthropology, 2009Co-Authors: Marie Louise Jørkov, Jan Heinemeier, Niels LynnerupAbstract:Intraskeletal variation in the composition of carbon (delta(13)C) and nitrogen (delta(15)N) stable isotopes measured in collagen is tested from various human Bones and dentine. Samples were taken from the femur, rib, and Petrous part of the temporal Bone from well-preserved skeletons of both adults (n = 34) and subadults (n = 24). Additional samples of dentine from the root of 1st molars were taken from 16 individuals. The skeletal material is from a medieval cemetery (AD 1200-1573) in Holbaek, Denmark. Our results indicate that the Petrous Bone has an isotopic signal that differs significantly from that of femur and rib within the single skeleton (P < 0.001 and P < 0.001, respectively), with only minor variation seen between femur and rib. On the other hand, there was no significant difference between the Petrous Bone and the 1st molar. The intraskeletal variation may reflect differences in turnover rate among skeletal elements. The inner periosteal layer of the Petrous Bone is formed in uterus and does not undergo any further remodelling after the age of 2 years, whereas the rib and femur have a continuous turnover rate of approximately 5 and 10-20 years, respectively. From the results of this study it is believed the Petrous Bone may be a new useful Bone element and a supplement or a proxy for teeth in the analysis of early dietary patterns as it may reflect diet in fetal stages and early years of life.
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The Petrous Bone—A new sampling site for identifying early dietary patterns in stable isotopic studies
American journal of physical anthropology, 2009Co-Authors: Marie Louise Jørkov, Jan Heinemeier, Niels LynnerupAbstract:Intraskeletal variation in the composition of carbon (delta(13)C) and nitrogen (delta(15)N) stable isotopes measured in collagen is tested from various human Bones and dentine. Samples were taken from the femur, rib, and Petrous part of the temporal Bone from well-preserved skeletons of both adults (n = 34) and subadults (n = 24). Additional samples of dentine from the root of 1st molars were taken from 16 individuals. The skeletal material is from a medieval cemetery (AD 1200-1573) in Holbaek, Denmark. Our results indicate that the Petrous Bone has an isotopic signal that differs significantly from that of femur and rib within the single skeleton (P < 0.001 and P < 0.001, respectively), with only minor variation seen between femur and rib. On the other hand, there was no significant difference between the Petrous Bone and the 1st molar. The intraskeletal variation may reflect differences in turnover rate among skeletal elements. The inner periosteal layer of the Petrous Bone is formed in uterus and does not undergo any further remodelling after the age of 2 years, whereas the rib and femur have a continuous turnover rate of approximately 5 and 10-20 years, respectively. From the results of this study it is believed the Petrous Bone may be a new useful Bone element and a supplement or a proxy for teeth in the analysis of early dietary patterns as it may reflect diet in fetal stages and early years of life.
Jean Régis - One of the best experts on this subject based on the ideXlab platform.
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Decision making for the surgical approach of posterior Petrous Bone meningiomas
Neurosurgical focus, 2011Co-Authors: Pierre-hugues Roche, Vincent Lubrano, Remy Noudel, Anthony Melot, Jean RégisAbstract:Object The authors undertook this study to examine the surgical approaches used to treat posterior Petrous Bone meningiomas at a single institution and retrospectively evaluate their surgical strategy based on a previously published classification. Methods Cases in which craniotomies were performed to treat posterior Petrous Bone meningiomas between 2002 and 2010 were retrospectively reviewed. Data were examined from 57 patients who were treated for 59 tumors. The tumors were classified into 3 types according to the location of their primary dural attachment: Type A, located around the porus trigeminus (33 tumors); Type M, located at the level of the porus of the internal auditory canal (IAC) (12 tumors); and Type P, located laterally to the IAC (14 tumors). The median tumor diameter was 34 mm (range 20–67 mm). Results The choice of the approach was based on tumor location, as the displacement of vascular structures and cranial nerves was primarily determined by the site of dural attachment on the posteri...
Michel Kalamarides - One of the best experts on this subject based on the ideXlab platform.
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posterior Petrous Bone meningiomas surgical experience in 53 patients and literature review
Neurosurgical Review, 2012Co-Authors: Matthieu Peyre, A Bozorggrayeli, Alain Rey, Olivier Sterkers, Michel KalamaridesAbstract:Meningiomas of the posterior fossa represent a heterogeneous group of tumors regarding difficulty of resection and functional outcome. The aim of this review was to focus on tumors located mainly on the posterior surface of the Petrous Bone and threatening hearing and facial functions. An anatomical classification was used to evaluate surgical outcome depending on the relationship of the tumor to the internal auditory meatus. The authors performed a retrospective chart review of 53 consecutive patients operated on for a posterior Petrous Bone meningioma in a tertiary referral center and a literature review. Tumors were classified in four groups according to the modified Desgeorges and Sterkers classification: posterior Petrous (P; 17 tumors), meatus and internal auditory canal (M; 12 tumors), Petrous apex without invasion of the internal auditory canal (A; 9 tumors), and cerebellopontine angle with invasion of the internal auditory canal (AMP; 15 tumors). The facial function was preserved in 100% of P and A tumors, 75% of group M tumors, and 53% of AMP tumors. Hearing preservation was attempted only in P, A, and M groups where rates of serviceable hearing preservation were 82%, 80%, and 66%, respectively. The cumulative rate of hearing preservation for AMP tumors was 45% in our literature review. The increased facial morbidity associated with AMP tumors compared with other groups was also confirmed by the review of the literature. In conclusion, this study shows that among posterior Petrous Bone meningiomas, tumors invading the internal auditory canal present with increased postoperative functional morbidity in spite of a tailored approach regarding dural insertion.
Wolfgang Freysinger - One of the best experts on this subject based on the ideXlab platform.
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Computer-aided surgery in the Petrous Bone.
The Laryngoscope, 1999Co-Authors: Andreas R. Gunkel, Michael Vogele, Arno Martin, Reto Bale, Walter F. Thumfart, Wolfgang FreysingerAbstract:Objectives: We demonstrate that computer-assisted frameless stereotactic navigation with the ISG/ELEKTA Viewing Wand system in the Petrous Bone is routinely possible with sufficient application accuracy. Methods: High-resolution computed tomography imaging is done with a dedicated structure attached to the mouthpiece of the Vogele-Bale-Hohner (VBH) head holder, an integral part of our intraoperative patient fixation. The patient image registration can be reliably performed before surgery in an unsterile environment with the registration structure of the mouthpiece. For intraoperative navigation either the position-sensitive articulated arm or the optical three-dimensional digitizer of the ISG/ELEKTA system is used. Results: In the operations of the Petrous Bone performed so far, i.e., mastoidectomy, cholesteatoma surgery, and lateral skull base revision surgery, the clinical value of three-dimensional navigation was clearly demonstrated with an application accuracy, constant throughout surgery, mostly limited only by the resolution of the computed tomography.
Pierre-hugues Roche - One of the best experts on this subject based on the ideXlab platform.
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Decision making for the surgical approach of posterior Petrous Bone meningiomas
Neurosurgical focus, 2011Co-Authors: Pierre-hugues Roche, Vincent Lubrano, Remy Noudel, Anthony Melot, Jean RégisAbstract:Object The authors undertook this study to examine the surgical approaches used to treat posterior Petrous Bone meningiomas at a single institution and retrospectively evaluate their surgical strategy based on a previously published classification. Methods Cases in which craniotomies were performed to treat posterior Petrous Bone meningiomas between 2002 and 2010 were retrospectively reviewed. Data were examined from 57 patients who were treated for 59 tumors. The tumors were classified into 3 types according to the location of their primary dural attachment: Type A, located around the porus trigeminus (33 tumors); Type M, located at the level of the porus of the internal auditory canal (IAC) (12 tumors); and Type P, located laterally to the IAC (14 tumors). The median tumor diameter was 34 mm (range 20–67 mm). Results The choice of the approach was based on tumor location, as the displacement of vascular structures and cranial nerves was primarily determined by the site of dural attachment on the posteri...